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-rw-r--r--compiler/rustc_codegen_llvm/src/abi.rs167
-rw-r--r--compiler/rustc_codegen_llvm/src/allocator.rs7
-rw-r--r--compiler/rustc_codegen_llvm/src/asm.rs93
-rw-r--r--compiler/rustc_codegen_llvm/src/attributes.rs110
-rw-r--r--compiler/rustc_codegen_llvm/src/back/archive.rs295
-rw-r--r--compiler/rustc_codegen_llvm/src/back/lto.rs140
-rw-r--r--compiler/rustc_codegen_llvm/src/back/write.rs319
-rw-r--r--compiler/rustc_codegen_llvm/src/base.rs13
-rw-r--r--compiler/rustc_codegen_llvm/src/builder.rs182
-rw-r--r--compiler/rustc_codegen_llvm/src/callee.rs31
-rw-r--r--compiler/rustc_codegen_llvm/src/common.rs138
-rw-r--r--compiler/rustc_codegen_llvm/src/consts.rs110
-rw-r--r--compiler/rustc_codegen_llvm/src/context.rs75
-rw-r--r--compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs9
-rw-r--r--compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs3
-rw-r--r--compiler/rustc_codegen_llvm/src/debuginfo/gdb.rs2
-rw-r--r--compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs33
-rw-r--r--compiler/rustc_codegen_llvm/src/debuginfo/metadata/enums/cpp_like.rs740
-rw-r--r--compiler/rustc_codegen_llvm/src/debuginfo/metadata/enums/mod.rs104
-rw-r--r--compiler/rustc_codegen_llvm/src/debuginfo/metadata/enums/native.rs12
-rw-r--r--compiler/rustc_codegen_llvm/src/debuginfo/metadata/type_map.rs22
-rw-r--r--compiler/rustc_codegen_llvm/src/debuginfo/mod.rs44
-rw-r--r--compiler/rustc_codegen_llvm/src/debuginfo/utils.rs4
-rw-r--r--compiler/rustc_codegen_llvm/src/declare.rs43
-rw-r--r--compiler/rustc_codegen_llvm/src/errors.rs120
-rw-r--r--compiler/rustc_codegen_llvm/src/intrinsic.rs167
-rw-r--r--compiler/rustc_codegen_llvm/src/lib.rs31
-rw-r--r--compiler/rustc_codegen_llvm/src/llvm/archive_ro.rs11
-rw-r--r--compiler/rustc_codegen_llvm/src/llvm/diagnostic.rs13
-rw-r--r--compiler/rustc_codegen_llvm/src/llvm/ffi.rs234
-rw-r--r--compiler/rustc_codegen_llvm/src/llvm/mod.rs21
-rw-r--r--compiler/rustc_codegen_llvm/src/llvm_util.rs189
-rw-r--r--compiler/rustc_codegen_llvm/src/mono_item.rs10
-rw-r--r--compiler/rustc_codegen_llvm/src/type_.rs40
-rw-r--r--compiler/rustc_codegen_llvm/src/type_of.rs5
35 files changed, 2049 insertions, 1488 deletions
diff --git a/compiler/rustc_codegen_llvm/src/abi.rs b/compiler/rustc_codegen_llvm/src/abi.rs
index cc8b3a1a4e4..a6fd2a7de6b 100644
--- a/compiler/rustc_codegen_llvm/src/abi.rs
+++ b/compiler/rustc_codegen_llvm/src/abi.rs
@@ -19,6 +19,7 @@ use rustc_target::abi::call::ArgAbi;
 pub use rustc_target::abi::call::*;
 use rustc_target::abi::{self, HasDataLayout, Int};
 pub use rustc_target::spec::abi::Abi;
+use rustc_target::spec::SanitizerSet;
 
 use libc::c_uint;
 use smallvec::SmallVec;
@@ -37,7 +38,7 @@ fn should_use_mutable_noalias(cx: &CodegenCx<'_, '_>) -> bool {
     // LLVM prior to version 12 had known miscompiles in the presence of
     // noalias attributes (see #54878), but we don't support earlier
     // versions at all anymore. We now enable mutable noalias by default.
-    cx.tcx.sess.opts.debugging_opts.mutable_noalias.unwrap_or(true)
+    cx.tcx.sess.opts.unstable_opts.mutable_noalias.unwrap_or(true)
 }
 
 const ABI_AFFECTING_ATTRIBUTES: [(ArgAttribute, llvm::AttributeKind); 1] =
@@ -90,6 +91,13 @@ fn get_attrs<'ll>(this: &ArgAttributes, cx: &CodegenCx<'ll, '_>) -> SmallVec<[&'
         if regular.contains(ArgAttribute::NoAliasMutRef) && should_use_mutable_noalias(cx) {
             attrs.push(llvm::AttributeKind::NoAlias.create_attr(cx.llcx));
         }
+    } else if cx.tcx.sess.opts.unstable_opts.sanitizer.contains(SanitizerSet::MEMORY) {
+        // If we're not optimising, *but* memory sanitizer is on, emit noundef, since it affects
+        // memory sanitizer's behavior.
+
+        if regular.contains(ArgAttribute::NoUndef) {
+            attrs.push(llvm::AttributeKind::NoUndef.create_attr(cx.llcx));
+        }
     }
 
     attrs
@@ -213,7 +221,7 @@ impl<'ll, 'tcx> ArgAbiExt<'ll, 'tcx> for ArgAbi<'tcx, Ty<'tcx>> {
             OperandValue::Ref(val, None, self.layout.align.abi).store(bx, dst)
         } else if self.is_unsized_indirect() {
             bug!("unsized `ArgAbi` must be handled through `store_fn_arg`");
-        } else if let PassMode::Cast(cast) = self.mode {
+        } else if let PassMode::Cast(cast, _) = &self.mode {
             // FIXME(eddyb): Figure out when the simpler Store is safe, clang
             // uses it for i16 -> {i8, i8}, but not for i24 -> {i8, i8, i8}.
             let can_store_through_cast_ptr = false;
@@ -283,7 +291,7 @@ impl<'ll, 'tcx> ArgAbiExt<'ll, 'tcx> for ArgAbi<'tcx, Ty<'tcx>> {
             }
             PassMode::Direct(_)
             | PassMode::Indirect { attrs: _, extra_attrs: None, on_stack: _ }
-            | PassMode::Cast(_) => {
+            | PassMode::Cast(..) => {
                 let next_arg = next();
                 self.store(bx, next_arg, dst);
             }
@@ -325,20 +333,18 @@ impl<'ll, 'tcx> FnAbiLlvmExt<'ll, 'tcx> for FnAbi<'tcx, Ty<'tcx>> {
     fn llvm_type(&self, cx: &CodegenCx<'ll, 'tcx>) -> &'ll Type {
         // Ignore "extra" args from the call site for C variadic functions.
         // Only the "fixed" args are part of the LLVM function signature.
-        let args = if self.c_variadic { &self.args[..self.fixed_count] } else { &self.args };
+        let args =
+            if self.c_variadic { &self.args[..self.fixed_count as usize] } else { &self.args };
 
-        let args_capacity: usize = args.iter().map(|arg|
-            if arg.pad.is_some() { 1 } else { 0 } +
-            if let PassMode::Pair(_, _) = arg.mode { 2 } else { 1 }
-        ).sum();
+        // This capacity calculation is approximate.
         let mut llargument_tys = Vec::with_capacity(
-            if let PassMode::Indirect { .. } = self.ret.mode { 1 } else { 0 } + args_capacity,
+            self.args.len() + if let PassMode::Indirect { .. } = self.ret.mode { 1 } else { 0 },
         );
 
-        let llreturn_ty = match self.ret.mode {
+        let llreturn_ty = match &self.ret.mode {
             PassMode::Ignore => cx.type_void(),
             PassMode::Direct(_) | PassMode::Pair(..) => self.ret.layout.immediate_llvm_type(cx),
-            PassMode::Cast(cast) => cast.llvm_type(cx),
+            PassMode::Cast(cast, _) => cast.llvm_type(cx),
             PassMode::Indirect { .. } => {
                 llargument_tys.push(cx.type_ptr_to(self.ret.memory_ty(cx)));
                 cx.type_void()
@@ -346,12 +352,7 @@ impl<'ll, 'tcx> FnAbiLlvmExt<'ll, 'tcx> for FnAbi<'tcx, Ty<'tcx>> {
         };
 
         for arg in args {
-            // add padding
-            if let Some(ty) = arg.pad {
-                llargument_tys.push(ty.llvm_type(cx));
-            }
-
-            let llarg_ty = match arg.mode {
+            let llarg_ty = match &arg.mode {
                 PassMode::Ignore => continue,
                 PassMode::Direct(_) => arg.layout.immediate_llvm_type(cx),
                 PassMode::Pair(..) => {
@@ -366,7 +367,13 @@ impl<'ll, 'tcx> FnAbiLlvmExt<'ll, 'tcx> for FnAbi<'tcx, Ty<'tcx>> {
                     llargument_tys.push(ptr_layout.scalar_pair_element_llvm_type(cx, 1, true));
                     continue;
                 }
-                PassMode::Cast(cast) => cast.llvm_type(cx),
+                PassMode::Cast(cast, pad_i32) => {
+                    // add padding
+                    if *pad_i32 {
+                        llargument_tys.push(Reg::i32().llvm_type(cx));
+                    }
+                    cast.llvm_type(cx)
+                }
                 PassMode::Indirect { attrs: _, extra_attrs: None, on_stack: _ } => {
                     cx.type_ptr_to(arg.memory_ty(cx))
                 }
@@ -391,23 +398,7 @@ impl<'ll, 'tcx> FnAbiLlvmExt<'ll, 'tcx> for FnAbi<'tcx, Ty<'tcx>> {
     }
 
     fn llvm_cconv(&self) -> llvm::CallConv {
-        match self.conv {
-            Conv::C | Conv::Rust | Conv::CCmseNonSecureCall => llvm::CCallConv,
-            Conv::RustCold => llvm::ColdCallConv,
-            Conv::AmdGpuKernel => llvm::AmdGpuKernel,
-            Conv::AvrInterrupt => llvm::AvrInterrupt,
-            Conv::AvrNonBlockingInterrupt => llvm::AvrNonBlockingInterrupt,
-            Conv::ArmAapcs => llvm::ArmAapcsCallConv,
-            Conv::Msp430Intr => llvm::Msp430Intr,
-            Conv::PtxKernel => llvm::PtxKernel,
-            Conv::X86Fastcall => llvm::X86FastcallCallConv,
-            Conv::X86Intr => llvm::X86_Intr,
-            Conv::X86Stdcall => llvm::X86StdcallCallConv,
-            Conv::X86ThisCall => llvm::X86_ThisCall,
-            Conv::X86VectorCall => llvm::X86_VectorCall,
-            Conv::X86_64SysV => llvm::X86_64_SysV,
-            Conv::X86_64Win64 => llvm::X86_64_Win64,
-        }
+        self.conv.into()
     }
 
     fn apply_attrs_llfn(&self, cx: &CodegenCx<'ll, 'tcx>, llfn: &'ll Value) {
@@ -426,46 +417,46 @@ impl<'ll, 'tcx> FnAbiLlvmExt<'ll, 'tcx> for FnAbi<'tcx, Ty<'tcx>> {
             i += 1;
             i - 1
         };
-        match self.ret.mode {
-            PassMode::Direct(ref attrs) => {
+        match &self.ret.mode {
+            PassMode::Direct(attrs) => {
                 attrs.apply_attrs_to_llfn(llvm::AttributePlace::ReturnValue, cx, llfn);
             }
-            PassMode::Indirect { ref attrs, extra_attrs: _, on_stack } => {
+            PassMode::Indirect { attrs, extra_attrs: _, on_stack } => {
                 assert!(!on_stack);
                 let i = apply(attrs);
                 let sret = llvm::CreateStructRetAttr(cx.llcx, self.ret.layout.llvm_type(cx));
                 attributes::apply_to_llfn(llfn, llvm::AttributePlace::Argument(i), &[sret]);
             }
-            PassMode::Cast(cast) => {
+            PassMode::Cast(cast, _) => {
                 cast.attrs.apply_attrs_to_llfn(llvm::AttributePlace::ReturnValue, cx, llfn);
             }
             _ => {}
         }
-        for arg in &self.args {
-            if arg.pad.is_some() {
-                apply(&ArgAttributes::new());
-            }
-            match arg.mode {
+        for arg in self.args.iter() {
+            match &arg.mode {
                 PassMode::Ignore => {}
-                PassMode::Indirect { ref attrs, extra_attrs: None, on_stack: true } => {
+                PassMode::Indirect { attrs, extra_attrs: None, on_stack: true } => {
                     let i = apply(attrs);
                     let byval = llvm::CreateByValAttr(cx.llcx, arg.layout.llvm_type(cx));
                     attributes::apply_to_llfn(llfn, llvm::AttributePlace::Argument(i), &[byval]);
                 }
-                PassMode::Direct(ref attrs)
-                | PassMode::Indirect { ref attrs, extra_attrs: None, on_stack: false } => {
+                PassMode::Direct(attrs)
+                | PassMode::Indirect { attrs, extra_attrs: None, on_stack: false } => {
                     apply(attrs);
                 }
-                PassMode::Indirect { ref attrs, extra_attrs: Some(ref extra_attrs), on_stack } => {
+                PassMode::Indirect { attrs, extra_attrs: Some(extra_attrs), on_stack } => {
                     assert!(!on_stack);
                     apply(attrs);
                     apply(extra_attrs);
                 }
-                PassMode::Pair(ref a, ref b) => {
+                PassMode::Pair(a, b) => {
                     apply(a);
                     apply(b);
                 }
-                PassMode::Cast(cast) => {
+                PassMode::Cast(cast, pad_i32) => {
+                    if *pad_i32 {
+                        apply(&ArgAttributes::new());
+                    }
                     apply(&cast.attrs);
                 }
             }
@@ -488,17 +479,17 @@ impl<'ll, 'tcx> FnAbiLlvmExt<'ll, 'tcx> for FnAbi<'tcx, Ty<'tcx>> {
             i += 1;
             i - 1
         };
-        match self.ret.mode {
-            PassMode::Direct(ref attrs) => {
+        match &self.ret.mode {
+            PassMode::Direct(attrs) => {
                 attrs.apply_attrs_to_callsite(llvm::AttributePlace::ReturnValue, bx.cx, callsite);
             }
-            PassMode::Indirect { ref attrs, extra_attrs: _, on_stack } => {
+            PassMode::Indirect { attrs, extra_attrs: _, on_stack } => {
                 assert!(!on_stack);
                 let i = apply(bx.cx, attrs);
                 let sret = llvm::CreateStructRetAttr(bx.cx.llcx, self.ret.layout.llvm_type(bx));
                 attributes::apply_to_callsite(callsite, llvm::AttributePlace::Argument(i), &[sret]);
             }
-            PassMode::Cast(cast) => {
+            PassMode::Cast(cast, _) => {
                 cast.attrs.apply_attrs_to_callsite(
                     llvm::AttributePlace::ReturnValue,
                     &bx.cx,
@@ -517,13 +508,10 @@ impl<'ll, 'tcx> FnAbiLlvmExt<'ll, 'tcx> for FnAbi<'tcx, Ty<'tcx>> {
                 }
             }
         }
-        for arg in &self.args {
-            if arg.pad.is_some() {
-                apply(bx.cx, &ArgAttributes::new());
-            }
-            match arg.mode {
+        for arg in self.args.iter() {
+            match &arg.mode {
                 PassMode::Ignore => {}
-                PassMode::Indirect { ref attrs, extra_attrs: None, on_stack: true } => {
+                PassMode::Indirect { attrs, extra_attrs: None, on_stack: true } => {
                     let i = apply(bx.cx, attrs);
                     let byval = llvm::CreateByValAttr(bx.cx.llcx, arg.layout.llvm_type(bx));
                     attributes::apply_to_callsite(
@@ -532,23 +520,22 @@ impl<'ll, 'tcx> FnAbiLlvmExt<'ll, 'tcx> for FnAbi<'tcx, Ty<'tcx>> {
                         &[byval],
                     );
                 }
-                PassMode::Direct(ref attrs)
-                | PassMode::Indirect { ref attrs, extra_attrs: None, on_stack: false } => {
+                PassMode::Direct(attrs)
+                | PassMode::Indirect { attrs, extra_attrs: None, on_stack: false } => {
                     apply(bx.cx, attrs);
                 }
-                PassMode::Indirect {
-                    ref attrs,
-                    extra_attrs: Some(ref extra_attrs),
-                    on_stack: _,
-                } => {
+                PassMode::Indirect { attrs, extra_attrs: Some(extra_attrs), on_stack: _ } => {
                     apply(bx.cx, attrs);
                     apply(bx.cx, extra_attrs);
                 }
-                PassMode::Pair(ref a, ref b) => {
+                PassMode::Pair(a, b) => {
                     apply(bx.cx, a);
                     apply(bx.cx, b);
                 }
-                PassMode::Cast(cast) => {
+                PassMode::Cast(cast, pad_i32) => {
+                    if *pad_i32 {
+                        apply(bx.cx, &ArgAttributes::new());
+                    }
                     apply(bx.cx, &cast.attrs);
                 }
             }
@@ -569,15 +556,49 @@ impl<'ll, 'tcx> FnAbiLlvmExt<'ll, 'tcx> for FnAbi<'tcx, Ty<'tcx>> {
                 &[cmse_nonsecure_call],
             );
         }
+
+        // Some intrinsics require that an elementtype attribute (with the pointee type of a
+        // pointer argument) is added to the callsite.
+        let element_type_index = unsafe { llvm::LLVMRustGetElementTypeArgIndex(callsite) };
+        if element_type_index >= 0 {
+            let arg_ty = self.args[element_type_index as usize].layout.ty;
+            let pointee_ty = arg_ty.builtin_deref(true).expect("Must be pointer argument").ty;
+            let element_type_attr = unsafe {
+                llvm::LLVMRustCreateElementTypeAttr(bx.llcx, bx.layout_of(pointee_ty).llvm_type(bx))
+            };
+            attributes::apply_to_callsite(
+                callsite,
+                llvm::AttributePlace::Argument(element_type_index as u32),
+                &[element_type_attr],
+            );
+        }
     }
 }
 
 impl<'tcx> AbiBuilderMethods<'tcx> for Builder<'_, '_, 'tcx> {
-    fn apply_attrs_callsite(&mut self, fn_abi: &FnAbi<'tcx, Ty<'tcx>>, callsite: Self::Value) {
-        fn_abi.apply_attrs_callsite(self, callsite)
-    }
-
     fn get_param(&mut self, index: usize) -> Self::Value {
         llvm::get_param(self.llfn(), index as c_uint)
     }
 }
+
+impl From<Conv> for llvm::CallConv {
+    fn from(conv: Conv) -> Self {
+        match conv {
+            Conv::C | Conv::Rust | Conv::CCmseNonSecureCall => llvm::CCallConv,
+            Conv::RustCold => llvm::ColdCallConv,
+            Conv::AmdGpuKernel => llvm::AmdGpuKernel,
+            Conv::AvrInterrupt => llvm::AvrInterrupt,
+            Conv::AvrNonBlockingInterrupt => llvm::AvrNonBlockingInterrupt,
+            Conv::ArmAapcs => llvm::ArmAapcsCallConv,
+            Conv::Msp430Intr => llvm::Msp430Intr,
+            Conv::PtxKernel => llvm::PtxKernel,
+            Conv::X86Fastcall => llvm::X86FastcallCallConv,
+            Conv::X86Intr => llvm::X86_Intr,
+            Conv::X86Stdcall => llvm::X86StdcallCallConv,
+            Conv::X86ThisCall => llvm::X86_ThisCall,
+            Conv::X86VectorCall => llvm::X86_VectorCall,
+            Conv::X86_64SysV => llvm::X86_64_SysV,
+            Conv::X86_64Win64 => llvm::X86_64_Win64,
+        }
+    }
+}
diff --git a/compiler/rustc_codegen_llvm/src/allocator.rs b/compiler/rustc_codegen_llvm/src/allocator.rs
index f935acb1a7e..fed56cdd438 100644
--- a/compiler/rustc_codegen_llvm/src/allocator.rs
+++ b/compiler/rustc_codegen_llvm/src/allocator.rs
@@ -15,7 +15,7 @@ pub(crate) unsafe fn codegen(
     module_llvm: &mut ModuleLlvm,
     module_name: &str,
     kind: AllocatorKind,
-    has_alloc_error_handler: bool,
+    alloc_error_handler_kind: AllocatorKind,
 ) {
     let llcx = &*module_llvm.llcx;
     let llmod = module_llvm.llmod();
@@ -117,8 +117,7 @@ pub(crate) unsafe fn codegen(
         attributes::apply_to_llfn(llfn, llvm::AttributePlace::Function, &[uwtable]);
     }
 
-    let kind = if has_alloc_error_handler { AllocatorKind::Global } else { AllocatorKind::Default };
-    let callee = kind.fn_name(sym::oom);
+    let callee = alloc_error_handler_kind.fn_name(sym::oom);
     let callee = llvm::LLVMRustGetOrInsertFunction(llmod, callee.as_ptr().cast(), callee.len(), ty);
     // -> ! DIFlagNoReturn
     attributes::apply_to_llfn(callee, llvm::AttributePlace::Function, &[no_return]);
@@ -145,7 +144,7 @@ pub(crate) unsafe fn codegen(
     if tcx.sess.target.default_hidden_visibility {
         llvm::LLVMRustSetVisibility(ll_g, llvm::Visibility::Hidden);
     }
-    let val = tcx.sess.opts.debugging_opts.oom.should_panic();
+    let val = tcx.sess.opts.unstable_opts.oom.should_panic();
     let llval = llvm::LLVMConstInt(i8, val as u64, False);
     llvm::LLVMSetInitializer(ll_g, llval);
 
diff --git a/compiler/rustc_codegen_llvm/src/asm.rs b/compiler/rustc_codegen_llvm/src/asm.rs
index a53946995ee..219a4f8fa89 100644
--- a/compiler/rustc_codegen_llvm/src/asm.rs
+++ b/compiler/rustc_codegen_llvm/src/asm.rs
@@ -3,7 +3,6 @@ use crate::builder::Builder;
 use crate::common::Funclet;
 use crate::context::CodegenCx;
 use crate::llvm;
-use crate::llvm_util;
 use crate::type_::Type;
 use crate::type_of::LayoutLlvmExt;
 use crate::value::Value;
@@ -20,7 +19,6 @@ use rustc_target::asm::*;
 
 use libc::{c_char, c_uint};
 use smallvec::SmallVec;
-use tracing::debug;
 
 impl<'ll, 'tcx> AsmBuilderMethods<'tcx> for Builder<'_, 'll, 'tcx> {
     fn codegen_inline_asm(
@@ -132,7 +130,7 @@ impl<'ll, 'tcx> AsmBuilderMethods<'tcx> for Builder<'_, 'll, 'tcx> {
                     op_idx.insert(idx, constraints.len());
                     constraints.push(reg_to_llvm(reg, Some(&value.layout)));
                 }
-                InlineAsmOperandRef::InOut { reg, late: _, in_value, out_place: _ } => {
+                InlineAsmOperandRef::InOut { reg, late, in_value, out_place: _ } => {
                     let value = llvm_fixup_input(
                         self,
                         in_value.immediate(),
@@ -140,7 +138,16 @@ impl<'ll, 'tcx> AsmBuilderMethods<'tcx> for Builder<'_, 'll, 'tcx> {
                         &in_value.layout,
                     );
                     inputs.push(value);
-                    constraints.push(format!("{}", op_idx[&idx]));
+
+                    // In the case of fixed registers, we have the choice of
+                    // either using a tied operand or duplicating the constraint.
+                    // We prefer the latter because it matches the behavior of
+                    // Clang.
+                    if late && matches!(reg, InlineAsmRegOrRegClass::Reg(_)) {
+                        constraints.push(format!("{}", reg_to_llvm(reg, Some(&in_value.layout))));
+                    } else {
+                        constraints.push(format!("{}", op_idx[&idx]));
+                    }
                 }
                 InlineAsmOperandRef::SymFn { instance } => {
                     inputs.push(self.cx.get_fn(instance));
@@ -278,13 +285,13 @@ impl<'ll, 'tcx> AsmBuilderMethods<'tcx> for Builder<'_, 'll, 'tcx> {
         let mut attrs = SmallVec::<[_; 2]>::new();
         if options.contains(InlineAsmOptions::PURE) {
             if options.contains(InlineAsmOptions::NOMEM) {
-                attrs.push(llvm::AttributeKind::ReadNone.create_attr(self.cx.llcx));
+                attrs.push(llvm::MemoryEffects::None.create_attr(self.cx.llcx));
             } else if options.contains(InlineAsmOptions::READONLY) {
-                attrs.push(llvm::AttributeKind::ReadOnly.create_attr(self.cx.llcx));
+                attrs.push(llvm::MemoryEffects::ReadOnly.create_attr(self.cx.llcx));
             }
             attrs.push(llvm::AttributeKind::WillReturn.create_attr(self.cx.llcx));
         } else if options.contains(InlineAsmOptions::NOMEM) {
-            attrs.push(llvm::AttributeKind::InaccessibleMemOnly.create_attr(self.cx.llcx));
+            attrs.push(llvm::MemoryEffects::InaccessibleMemOnly.create_attr(self.cx.llcx));
         } else {
             // LLVM doesn't have an attribute to represent ReadOnly + SideEffect
         }
@@ -419,13 +426,6 @@ pub(crate) fn inline_asm_call<'ll>(
         let constraints_ok = llvm::LLVMRustInlineAsmVerify(fty, cons.as_ptr().cast(), cons.len());
         debug!("constraint verification result: {:?}", constraints_ok);
         if constraints_ok {
-            if unwind && llvm_util::get_version() < (13, 0, 0) {
-                bx.cx.sess().span_fatal(
-                    line_spans[0],
-                    "unwinding from inline assembly is only supported on llvm >= 13.",
-                );
-            }
-
             let v = llvm::LLVMRustInlineAsm(
                 fty,
                 asm.as_ptr().cast(),
@@ -439,9 +439,9 @@ pub(crate) fn inline_asm_call<'ll>(
             );
 
             let call = if let Some((dest, catch, funclet)) = dest_catch_funclet {
-                bx.invoke(fty, v, inputs, dest, catch, funclet)
+                bx.invoke(fty, None, v, inputs, dest, catch, funclet)
             } else {
-                bx.call(fty, v, inputs, None)
+                bx.call(fty, None, v, inputs, None)
             };
 
             // Store mark in a metadata node so we can map LLVM errors
@@ -505,6 +505,44 @@ fn xmm_reg_index(reg: InlineAsmReg) -> Option<u32> {
     }
 }
 
+/// If the register is an AArch64 integer register then return its index.
+fn a64_reg_index(reg: InlineAsmReg) -> Option<u32> {
+    match reg {
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x0) => Some(0),
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x1) => Some(1),
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x2) => Some(2),
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x3) => Some(3),
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x4) => Some(4),
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x5) => Some(5),
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x6) => Some(6),
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x7) => Some(7),
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x8) => Some(8),
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x9) => Some(9),
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x10) => Some(10),
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x11) => Some(11),
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x12) => Some(12),
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x13) => Some(13),
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x14) => Some(14),
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x15) => Some(15),
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x16) => Some(16),
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x17) => Some(17),
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x18) => Some(18),
+        // x19 is reserved
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x20) => Some(20),
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x21) => Some(21),
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x22) => Some(22),
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x23) => Some(23),
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x24) => Some(24),
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x25) => Some(25),
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x26) => Some(26),
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x27) => Some(27),
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x28) => Some(28),
+        // x29 is reserved
+        InlineAsmReg::AArch64(AArch64InlineAsmReg::x30) => Some(30),
+        _ => None,
+    }
+}
+
 /// If the register is an AArch64 vector register then return its index.
 fn a64_vreg_index(reg: InlineAsmReg) -> Option<u32> {
     match reg {
@@ -535,6 +573,22 @@ fn reg_to_llvm(reg: InlineAsmRegOrRegClass, layout: Option<&TyAndLayout<'_>>) ->
                     'x'
                 };
                 format!("{{{}mm{}}}", class, idx)
+            } else if let Some(idx) = a64_reg_index(reg) {
+                let class = if let Some(layout) = layout {
+                    match layout.size.bytes() {
+                        8 => 'x',
+                        _ => 'w',
+                    }
+                } else {
+                    // We use i32 as the type for discarded outputs
+                    'w'
+                };
+                if class == 'x' && reg == InlineAsmReg::AArch64(AArch64InlineAsmReg::x30) {
+                    // LLVM doesn't recognize x30. use lr instead.
+                    "{lr}".to_string()
+                } else {
+                    format!("{{{}{}}}", class, idx)
+                }
             } else if let Some(idx) = a64_vreg_index(reg) {
                 let class = if let Some(layout) = layout {
                     match layout.size.bytes() {
@@ -550,9 +604,6 @@ fn reg_to_llvm(reg: InlineAsmRegOrRegClass, layout: Option<&TyAndLayout<'_>>) ->
                     'q'
                 };
                 format!("{{{}{}}}", class, idx)
-            } else if reg == InlineAsmReg::AArch64(AArch64InlineAsmReg::x30) {
-                // LLVM doesn't recognize x30
-                "{lr}".to_string()
             } else if reg == InlineAsmReg::Arm(ArmInlineAsmReg::r14) {
                 // LLVM doesn't recognize r14
                 "{lr}".to_string()
@@ -560,6 +611,8 @@ fn reg_to_llvm(reg: InlineAsmRegOrRegClass, layout: Option<&TyAndLayout<'_>>) ->
                 format!("{{{}}}", reg.name())
             }
         }
+        // The constraints can be retrieved from
+        // https://llvm.org/docs/LangRef.html#supported-constraint-code-list
         InlineAsmRegOrRegClass::RegClass(reg) => match reg {
             InlineAsmRegClass::AArch64(AArch64InlineAsmRegClass::reg) => "r",
             InlineAsmRegClass::AArch64(AArch64InlineAsmRegClass::vreg) => "w",
@@ -633,6 +686,8 @@ fn modifier_to_llvm(
     reg: InlineAsmRegClass,
     modifier: Option<char>,
 ) -> Option<char> {
+    // The modifiers can be retrieved from
+    // https://llvm.org/docs/LangRef.html#asm-template-argument-modifiers
     match reg {
         InlineAsmRegClass::AArch64(AArch64InlineAsmRegClass::reg) => modifier,
         InlineAsmRegClass::AArch64(AArch64InlineAsmRegClass::vreg)
diff --git a/compiler/rustc_codegen_llvm/src/attributes.rs b/compiler/rustc_codegen_llvm/src/attributes.rs
index 9394d60134f..f3bdacf6085 100644
--- a/compiler/rustc_codegen_llvm/src/attributes.rs
+++ b/compiler/rustc_codegen_llvm/src/attributes.rs
@@ -12,8 +12,9 @@ use rustc_target::spec::{FramePointer, SanitizerSet, StackProbeType, StackProtec
 use smallvec::SmallVec;
 
 use crate::attributes;
+use crate::errors::{MissingFeatures, SanitizerMemtagRequiresMte, TargetFeatureDisableOrEnable};
 use crate::llvm::AttributePlace::Function;
-use crate::llvm::{self, Attribute, AttributeKind, AttributePlace};
+use crate::llvm::{self, AllocKindFlags, Attribute, AttributeKind, AttributePlace, MemoryEffects};
 use crate::llvm_util;
 pub use rustc_attr::{InlineAttr, InstructionSetAttr, OptimizeAttr};
 
@@ -35,6 +36,10 @@ pub fn apply_to_callsite(callsite: &Value, idx: AttributePlace, attrs: &[&Attrib
 /// Get LLVM attribute for the provided inline heuristic.
 #[inline]
 fn inline_attr<'ll>(cx: &CodegenCx<'ll, '_>, inline: InlineAttr) -> Option<&'ll Attribute> {
+    if !cx.tcx.sess.opts.unstable_opts.inline_llvm {
+        // disable LLVM inlining
+        return Some(AttributeKind::NoInline.create_attr(cx.llcx));
+    }
     match inline {
         InlineAttr::Hint => Some(AttributeKind::InlineHint.create_attr(cx.llcx)),
         InlineAttr::Always => Some(AttributeKind::AlwaysInline.create_attr(cx.llcx)),
@@ -56,7 +61,7 @@ pub fn sanitize_attrs<'ll>(
     no_sanitize: SanitizerSet,
 ) -> SmallVec<[&'ll Attribute; 4]> {
     let mut attrs = SmallVec::new();
-    let enabled = cx.tcx.sess.opts.debugging_opts.sanitizer - no_sanitize;
+    let enabled = cx.tcx.sess.opts.unstable_opts.sanitizer - no_sanitize;
     if enabled.contains(SanitizerSet::ADDRESS) {
         attrs.push(llvm::AttributeKind::SanitizeAddress.create_attr(cx.llcx));
     }
@@ -69,13 +74,16 @@ pub fn sanitize_attrs<'ll>(
     if enabled.contains(SanitizerSet::HWADDRESS) {
         attrs.push(llvm::AttributeKind::SanitizeHWAddress.create_attr(cx.llcx));
     }
+    if enabled.contains(SanitizerSet::SHADOWCALLSTACK) {
+        attrs.push(llvm::AttributeKind::ShadowCallStack.create_attr(cx.llcx));
+    }
     if enabled.contains(SanitizerSet::MEMTAG) {
         // Check to make sure the mte target feature is actually enabled.
         let features = cx.tcx.global_backend_features(());
         let mte_feature =
             features.iter().map(|s| &s[..]).rfind(|n| ["+mte", "-mte"].contains(&&n[..]));
         if let None | Some("-mte") = mte_feature {
-            cx.tcx.sess.err("`-Zsanitizer=memtag` requires `-Ctarget-feature=+mte`");
+            cx.tcx.sess.emit_err(SanitizerMemtagRequiresMte);
         }
 
         attrs.push(llvm::AttributeKind::SanitizeMemTag.create_attr(cx.llcx));
@@ -136,7 +144,7 @@ fn probestack_attr<'ll>(cx: &CodegenCx<'ll, '_>) -> Option<&'ll Attribute> {
     if cx
         .sess()
         .opts
-        .debugging_opts
+        .unstable_opts
         .sanitizer
         .intersects(SanitizerSet::ADDRESS | SanitizerSet::THREAD)
     {
@@ -149,7 +157,7 @@ fn probestack_attr<'ll>(cx: &CodegenCx<'ll, '_>) -> Option<&'ll Attribute> {
     }
 
     // probestack doesn't play nice either with gcov profiling.
-    if cx.sess().opts.debugging_opts.profile {
+    if cx.sess().opts.unstable_opts.profile {
         return None;
     }
 
@@ -224,6 +232,10 @@ pub(crate) fn default_optimisation_attrs<'ll>(
     attrs
 }
 
+fn create_alloc_family_attr(llcx: &llvm::Context) -> &llvm::Attribute {
+    llvm::CreateAttrStringValue(llcx, "alloc-family", "__rust_alloc")
+}
+
 /// Composite function which sets LLVM attributes for function depending on its AST (`#[attribute]`)
 /// attributes.
 pub fn from_fn_attrs<'ll, 'tcx>(
@@ -246,13 +258,12 @@ pub fn from_fn_attrs<'ll, 'tcx>(
         OptimizeAttr::Speed => {}
     }
 
-    let inline = if codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::NAKED) {
-        InlineAttr::Never
-    } else if codegen_fn_attrs.inline == InlineAttr::None && instance.def.requires_inline(cx.tcx) {
-        InlineAttr::Hint
-    } else {
-        codegen_fn_attrs.inline
-    };
+    let inline =
+        if codegen_fn_attrs.inline == InlineAttr::None && instance.def.requires_inline(cx.tcx) {
+            InlineAttr::Hint
+        } else {
+            codegen_fn_attrs.inline
+        };
     to_add.extend(inline_attr(cx, inline));
 
     // The `uwtable` attribute according to LLVM is:
@@ -275,7 +286,7 @@ pub fn from_fn_attrs<'ll, 'tcx>(
         to_add.push(uwtable_attr(cx.llcx));
     }
 
-    if cx.sess().opts.debugging_opts.profile_sample_use.is_some() {
+    if cx.sess().opts.unstable_opts.profile_sample_use.is_some() {
         to_add.push(llvm::CreateAttrString(cx.llcx, "use-sample-profile"));
     }
 
@@ -292,19 +303,68 @@ pub fn from_fn_attrs<'ll, 'tcx>(
         to_add.push(AttributeKind::ReturnsTwice.create_attr(cx.llcx));
     }
     if codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::FFI_PURE) {
-        to_add.push(AttributeKind::ReadOnly.create_attr(cx.llcx));
+        to_add.push(MemoryEffects::ReadOnly.create_attr(cx.llcx));
     }
     if codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::FFI_CONST) {
-        to_add.push(AttributeKind::ReadNone.create_attr(cx.llcx));
+        to_add.push(MemoryEffects::None.create_attr(cx.llcx));
     }
     if codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::NAKED) {
         to_add.push(AttributeKind::Naked.create_attr(cx.llcx));
+        // HACK(jubilee): "indirect branch tracking" works by attaching prologues to functions.
+        // And it is a module-level attribute, so the alternative is pulling naked functions into new LLVM modules.
+        // Otherwise LLVM's "naked" functions come with endbr prefixes per https://github.com/rust-lang/rust/issues/98768
+        to_add.push(AttributeKind::NoCfCheck.create_attr(cx.llcx));
+        // Need this for AArch64.
+        to_add.push(llvm::CreateAttrStringValue(cx.llcx, "branch-target-enforcement", "false"));
     }
-    if codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::ALLOCATOR) {
+    if codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::ALLOCATOR)
+        || codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::ALLOCATOR_ZEROED)
+    {
+        if llvm_util::get_version() >= (15, 0, 0) {
+            to_add.push(create_alloc_family_attr(cx.llcx));
+            // apply to argument place instead of function
+            let alloc_align = AttributeKind::AllocAlign.create_attr(cx.llcx);
+            attributes::apply_to_llfn(llfn, AttributePlace::Argument(1), &[alloc_align]);
+            to_add.push(llvm::CreateAllocSizeAttr(cx.llcx, 0));
+            let mut flags = AllocKindFlags::Alloc | AllocKindFlags::Aligned;
+            if codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::ALLOCATOR) {
+                flags |= AllocKindFlags::Uninitialized;
+            } else {
+                flags |= AllocKindFlags::Zeroed;
+            }
+            to_add.push(llvm::CreateAllocKindAttr(cx.llcx, flags));
+        }
         // apply to return place instead of function (unlike all other attributes applied in this function)
         let no_alias = AttributeKind::NoAlias.create_attr(cx.llcx);
         attributes::apply_to_llfn(llfn, AttributePlace::ReturnValue, &[no_alias]);
     }
+    if codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::REALLOCATOR) {
+        if llvm_util::get_version() >= (15, 0, 0) {
+            to_add.push(create_alloc_family_attr(cx.llcx));
+            to_add.push(llvm::CreateAllocKindAttr(
+                cx.llcx,
+                AllocKindFlags::Realloc | AllocKindFlags::Aligned,
+            ));
+            // applies to argument place instead of function place
+            let allocated_pointer = AttributeKind::AllocatedPointer.create_attr(cx.llcx);
+            attributes::apply_to_llfn(llfn, AttributePlace::Argument(0), &[allocated_pointer]);
+            // apply to argument place instead of function
+            let alloc_align = AttributeKind::AllocAlign.create_attr(cx.llcx);
+            attributes::apply_to_llfn(llfn, AttributePlace::Argument(2), &[alloc_align]);
+            to_add.push(llvm::CreateAllocSizeAttr(cx.llcx, 3));
+        }
+        let no_alias = AttributeKind::NoAlias.create_attr(cx.llcx);
+        attributes::apply_to_llfn(llfn, AttributePlace::ReturnValue, &[no_alias]);
+    }
+    if codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::DEALLOCATOR) {
+        if llvm_util::get_version() >= (15, 0, 0) {
+            to_add.push(create_alloc_family_attr(cx.llcx));
+            to_add.push(llvm::CreateAllocKindAttr(cx.llcx, AllocKindFlags::Free));
+            // applies to argument place instead of function place
+            let allocated_pointer = AttributeKind::AllocatedPointer.create_attr(cx.llcx);
+            attributes::apply_to_llfn(llfn, AttributePlace::Argument(0), &[allocated_pointer]);
+        }
+    }
     if codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::CMSE_NONSECURE_ENTRY) {
         to_add.push(llvm::CreateAttrString(cx.llcx, "cmse_nonsecure_entry"));
     }
@@ -330,15 +390,17 @@ pub fn from_fn_attrs<'ll, 'tcx>(
     ) {
         let span = cx
             .tcx
-            .get_attr(instance.def_id(), sym::target_feature)
+            .get_attrs(instance.def_id(), sym::target_feature)
+            .next()
             .map_or_else(|| cx.tcx.def_span(instance.def_id()), |a| a.span);
-        let msg = format!(
-            "the target features {} must all be either enabled or disabled together",
-            f.join(", ")
-        );
-        let mut err = cx.tcx.sess.struct_span_err(span, &msg);
-        err.help("add the missing features in a `target_feature` attribute");
-        err.emit();
+        cx.tcx
+            .sess
+            .create_err(TargetFeatureDisableOrEnable {
+                features: f,
+                span: Some(span),
+                missing_features: Some(MissingFeatures),
+            })
+            .emit();
         return;
     }
 
diff --git a/compiler/rustc_codegen_llvm/src/back/archive.rs b/compiler/rustc_codegen_llvm/src/back/archive.rs
index 8f6438e85ad..0aee1a1439b 100644
--- a/compiler/rustc_codegen_llvm/src/back/archive.rs
+++ b/compiler/rustc_codegen_llvm/src/back/archive.rs
@@ -1,33 +1,32 @@
 //! A helper class for dealing with static archives
 
 use std::env;
-use std::ffi::{CStr, CString, OsString};
+use std::ffi::{c_char, c_void, CStr, CString, OsString};
 use std::io;
 use std::mem;
 use std::path::{Path, PathBuf};
 use std::ptr;
 use std::str;
 
+use crate::common;
+use crate::errors::{
+    DlltoolFailImportLibrary, ErrorCallingDllTool, ErrorCreatingImportLibrary, ErrorWritingDEFFile,
+};
 use crate::llvm::archive_ro::{ArchiveRO, Child};
 use crate::llvm::{self, ArchiveKind, LLVMMachineType, LLVMRustCOFFShortExport};
-use rustc_codegen_ssa::back::archive::ArchiveBuilder;
-use rustc_data_structures::temp_dir::MaybeTempDir;
-use rustc_session::cstore::{DllCallingConvention, DllImport};
-use rustc_session::Session;
+use rustc_codegen_ssa::back::archive::{
+    get_native_object_symbols, try_extract_macho_fat_archive, ArArchiveBuilder,
+    ArchiveBuildFailure, ArchiveBuilder, ArchiveBuilderBuilder, UnknownArchiveKind,
+};
 
-struct ArchiveConfig<'a> {
-    pub sess: &'a Session,
-    pub dst: PathBuf,
-    pub src: Option<PathBuf>,
-}
+use rustc_session::cstore::DllImport;
+use rustc_session::Session;
 
 /// Helper for adding many files to an archive.
 #[must_use = "must call build() to finish building the archive"]
-pub struct LlvmArchiveBuilder<'a> {
-    config: ArchiveConfig<'a>,
-    removals: Vec<String>,
+pub(crate) struct LlvmArchiveBuilder<'a> {
+    sess: &'a Session,
     additions: Vec<Addition>,
-    src_archive: Option<Option<ArchiveRO>>,
 }
 
 enum Addition {
@@ -50,10 +49,6 @@ fn is_relevant_child(c: &Child<'_>) -> bool {
     }
 }
 
-fn archive_config<'a>(sess: &'a Session, output: &Path, input: Option<&Path>) -> ArchiveConfig<'a> {
-    ArchiveConfig { sess, dst: output.to_path_buf(), src: input.map(|p| p.to_path_buf()) }
-}
-
 /// Map machine type strings to values of LLVM's MachineTypes enum.
 fn llvm_machine_type(cpu: &str) -> LLVMMachineType {
     match cpu {
@@ -66,46 +61,18 @@ fn llvm_machine_type(cpu: &str) -> LLVMMachineType {
 }
 
 impl<'a> ArchiveBuilder<'a> for LlvmArchiveBuilder<'a> {
-    /// Creates a new static archive, ready for modifying the archive specified
-    /// by `config`.
-    fn new(sess: &'a Session, output: &Path, input: Option<&Path>) -> LlvmArchiveBuilder<'a> {
-        let config = archive_config(sess, output, input);
-        LlvmArchiveBuilder {
-            config,
-            removals: Vec::new(),
-            additions: Vec::new(),
-            src_archive: None,
-        }
-    }
-
-    /// Removes a file from this archive
-    fn remove_file(&mut self, file: &str) {
-        self.removals.push(file.to_string());
-    }
-
-    /// Lists all files in an archive
-    fn src_files(&mut self) -> Vec<String> {
-        if self.src_archive().is_none() {
-            return Vec::new();
+    fn add_archive(
+        &mut self,
+        archive: &Path,
+        skip: Box<dyn FnMut(&str) -> bool + 'static>,
+    ) -> io::Result<()> {
+        let mut archive = archive.to_path_buf();
+        if self.sess.target.llvm_target.contains("-apple-macosx") {
+            if let Some(new_archive) = try_extract_macho_fat_archive(&self.sess, &archive)? {
+                archive = new_archive
+            }
         }
-
-        let archive = self.src_archive.as_ref().unwrap().as_ref().unwrap();
-
-        archive
-            .iter()
-            .filter_map(|child| child.ok())
-            .filter(is_relevant_child)
-            .filter_map(|child| child.name())
-            .filter(|name| !self.removals.iter().any(|x| x == name))
-            .map(|name| name.to_owned())
-            .collect()
-    }
-
-    fn add_archive<F>(&mut self, archive: &Path, skip: F) -> io::Result<()>
-    where
-        F: FnMut(&str) -> bool + 'static,
-    {
-        let archive_ro = match ArchiveRO::open(archive) {
+        let archive_ro = match ArchiveRO::open(&archive) {
             Ok(ar) => ar,
             Err(e) => return Err(io::Error::new(io::ErrorKind::Other, e)),
         };
@@ -113,7 +80,7 @@ impl<'a> ArchiveBuilder<'a> for LlvmArchiveBuilder<'a> {
             return Ok(());
         }
         self.additions.push(Addition::Archive {
-            path: archive.to_path_buf(),
+            path: archive,
             archive: archive_ro,
             skip: Box::new(skip),
         });
@@ -129,44 +96,53 @@ impl<'a> ArchiveBuilder<'a> for LlvmArchiveBuilder<'a> {
 
     /// Combine the provided files, rlibs, and native libraries into a single
     /// `Archive`.
-    fn build(mut self) {
-        let kind = self.llvm_archive_kind().unwrap_or_else(|kind| {
-            self.config.sess.fatal(&format!("Don't know how to build archive of type: {}", kind))
-        });
+    fn build(mut self: Box<Self>, output: &Path) -> bool {
+        match self.build_with_llvm(output) {
+            Ok(any_members) => any_members,
+            Err(e) => self.sess.emit_fatal(ArchiveBuildFailure { error: e }),
+        }
+    }
+}
+
+pub struct LlvmArchiveBuilderBuilder;
 
-        if let Err(e) = self.build_with_llvm(kind) {
-            self.config.sess.fatal(&format!("failed to build archive: {}", e));
+impl ArchiveBuilderBuilder for LlvmArchiveBuilderBuilder {
+    fn new_archive_builder<'a>(&self, sess: &'a Session) -> Box<dyn ArchiveBuilder<'a> + 'a> {
+        if sess.target.arch == "wasm32" || sess.target.arch == "wasm64" {
+            Box::new(LlvmArchiveBuilder { sess, additions: Vec::new() })
+        } else {
+            Box::new(ArArchiveBuilder::new(sess, get_llvm_object_symbols))
         }
     }
 
-    fn inject_dll_import_lib(
-        &mut self,
+    fn create_dll_import_lib(
+        &self,
+        sess: &Session,
         lib_name: &str,
         dll_imports: &[DllImport],
-        tmpdir: &MaybeTempDir,
-    ) {
+        tmpdir: &Path,
+        is_direct_dependency: bool,
+    ) -> PathBuf {
+        let name_suffix = if is_direct_dependency { "_imports" } else { "_imports_indirect" };
         let output_path = {
-            let mut output_path: PathBuf = tmpdir.as_ref().to_path_buf();
-            output_path.push(format!("{}_imports", lib_name));
+            let mut output_path: PathBuf = tmpdir.to_path_buf();
+            output_path.push(format!("{}{}", lib_name, name_suffix));
             output_path.with_extension("lib")
         };
 
-        let target = &self.config.sess.target;
-        let mingw_gnu_toolchain = target.vendor == "pc"
-            && target.os == "windows"
-            && target.env == "gnu"
-            && target.abi.is_empty();
+        let target = &sess.target;
+        let mingw_gnu_toolchain = common::is_mingw_gnu_toolchain(target);
 
         let import_name_and_ordinal_vector: Vec<(String, Option<u16>)> = dll_imports
             .iter()
             .map(|import: &DllImport| {
-                if self.config.sess.target.arch == "x86" {
+                if sess.target.arch == "x86" {
                     (
-                        LlvmArchiveBuilder::i686_decorated_name(import, mingw_gnu_toolchain),
-                        import.ordinal,
+                        common::i686_decorated_name(import, mingw_gnu_toolchain, false),
+                        import.ordinal(),
                     )
                 } else {
-                    (import.name.to_string(), import.ordinal)
+                    (import.name.to_string(), import.ordinal())
                 }
             })
             .collect();
@@ -178,7 +154,7 @@ impl<'a> ArchiveBuilder<'a> for LlvmArchiveBuilder<'a> {
             // functions.  Therefore, use binutils to create the import library instead,
             // by writing a .DEF file to the temp dir and calling binutils's dlltool.
             let def_file_path =
-                tmpdir.as_ref().join(format!("{}_imports", lib_name)).with_extension("def");
+                tmpdir.join(format!("{}{}", lib_name, name_suffix)).with_extension("def");
 
             let def_file_content = format!(
                 "EXPORTS\n{}",
@@ -197,11 +173,14 @@ impl<'a> ArchiveBuilder<'a> for LlvmArchiveBuilder<'a> {
             match std::fs::write(&def_file_path, def_file_content) {
                 Ok(_) => {}
                 Err(e) => {
-                    self.config.sess.fatal(&format!("Error writing .DEF file: {}", e));
+                    sess.emit_fatal(ErrorWritingDEFFile { error: e });
                 }
             };
 
-            let dlltool = find_binutils_dlltool(self.config.sess);
+            // --no-leading-underscore: For the `import_name_type` feature to work, we need to be
+            // able to control the *exact* spelling of each of the symbols that are being imported:
+            // hence we don't want `dlltool` adding leading underscores automatically.
+            let dlltool = find_binutils_dlltool(sess);
             let result = std::process::Command::new(dlltool)
                 .args([
                     "-d",
@@ -210,18 +189,20 @@ impl<'a> ArchiveBuilder<'a> for LlvmArchiveBuilder<'a> {
                     lib_name,
                     "-l",
                     output_path.to_str().unwrap(),
+                    "--no-leading-underscore",
                 ])
                 .output();
 
             match result {
                 Err(e) => {
-                    self.config.sess.fatal(&format!("Error calling dlltool: {}", e));
+                    sess.emit_fatal(ErrorCallingDllTool { error: e });
+                }
+                Ok(output) if !output.status.success() => {
+                    sess.emit_fatal(DlltoolFailImportLibrary {
+                        stdout: String::from_utf8_lossy(&output.stdout),
+                        stderr: String::from_utf8_lossy(&output.stderr),
+                    })
                 }
-                Ok(output) if !output.status.success() => self.config.sess.fatal(&format!(
-                    "Dlltool could not create import library: {}\n{}",
-                    String::from_utf8_lossy(&output.stdout),
-                    String::from_utf8_lossy(&output.stderr)
-                )),
                 _ => {}
             }
         } else {
@@ -230,10 +211,10 @@ impl<'a> ArchiveBuilder<'a> for LlvmArchiveBuilder<'a> {
 
             let output_path_z = rustc_fs_util::path_to_c_string(&output_path);
 
-            tracing::trace!("invoking LLVMRustWriteImportLibrary");
-            tracing::trace!("  dll_name {:#?}", dll_name_z);
-            tracing::trace!("  output_path {}", output_path.display());
-            tracing::trace!(
+            trace!("invoking LLVMRustWriteImportLibrary");
+            trace!("  dll_name {:#?}", dll_name_z);
+            trace!("  output_path {}", output_path.display());
+            trace!(
                 "  import names: {}",
                 dll_imports
                     .iter()
@@ -263,71 +244,93 @@ impl<'a> ArchiveBuilder<'a> for LlvmArchiveBuilder<'a> {
                     output_path_z.as_ptr(),
                     ffi_exports.as_ptr(),
                     ffi_exports.len(),
-                    llvm_machine_type(&self.config.sess.target.arch) as u16,
-                    !self.config.sess.target.is_like_msvc,
+                    llvm_machine_type(&sess.target.arch) as u16,
+                    !sess.target.is_like_msvc,
                 )
             };
 
             if result == crate::llvm::LLVMRustResult::Failure {
-                self.config.sess.fatal(&format!(
-                    "Error creating import library for {}: {}",
+                sess.emit_fatal(ErrorCreatingImportLibrary {
                     lib_name,
-                    llvm::last_error().unwrap_or("unknown LLVM error".to_string())
-                ));
+                    error: llvm::last_error().unwrap_or("unknown LLVM error".to_string()),
+                });
             }
         };
 
-        self.add_archive(&output_path, |_| false).unwrap_or_else(|e| {
-            self.config.sess.fatal(&format!(
-                "failed to add native library {}: {}",
-                output_path.display(),
-                e
-            ));
-        });
+        output_path
     }
 }
 
-impl<'a> LlvmArchiveBuilder<'a> {
-    fn src_archive(&mut self) -> Option<&ArchiveRO> {
-        if let Some(ref a) = self.src_archive {
-            return a.as_ref();
+// The object crate doesn't know how to get symbols for LLVM bitcode and COFF bigobj files.
+// As such we need to use LLVM for them.
+#[deny(unsafe_op_in_unsafe_fn)]
+fn get_llvm_object_symbols(
+    buf: &[u8],
+    f: &mut dyn FnMut(&[u8]) -> io::Result<()>,
+) -> io::Result<bool> {
+    let is_bitcode = unsafe { llvm::LLVMRustIsBitcode(buf.as_ptr(), buf.len()) };
+
+    // COFF bigobj file, msvc LTO file or import library. See
+    // https://github.com/llvm/llvm-project/blob/453f27bc9/llvm/lib/BinaryFormat/Magic.cpp#L38-L51
+    let is_unsupported_windows_obj_file = buf.get(0..4) == Some(b"\0\0\xFF\xFF");
+
+    if is_bitcode || is_unsupported_windows_obj_file {
+        let mut state = Box::new(f);
+
+        let err = unsafe {
+            llvm::LLVMRustGetSymbols(
+                buf.as_ptr(),
+                buf.len(),
+                &mut *state as *mut &mut _ as *mut c_void,
+                callback,
+                error_callback,
+            )
+        };
+
+        if err.is_null() {
+            return Ok(true);
+        } else {
+            return Err(unsafe { *Box::from_raw(err as *mut io::Error) });
         }
-        let src = self.config.src.as_ref()?;
-        self.src_archive = Some(ArchiveRO::open(src).ok());
-        self.src_archive.as_ref().unwrap().as_ref()
-    }
 
-    fn llvm_archive_kind(&self) -> Result<ArchiveKind, &str> {
-        let kind = &*self.config.sess.target.archive_format;
-        kind.parse().map_err(|_| kind)
+        unsafe extern "C" fn callback(
+            state: *mut c_void,
+            symbol_name: *const c_char,
+        ) -> *mut c_void {
+            let f = unsafe { &mut *(state as *mut &mut dyn FnMut(&[u8]) -> io::Result<()>) };
+            match f(unsafe { CStr::from_ptr(symbol_name) }.to_bytes()) {
+                Ok(()) => std::ptr::null_mut(),
+                Err(err) => Box::into_raw(Box::new(err)) as *mut c_void,
+            }
+        }
+
+        unsafe extern "C" fn error_callback(error: *const c_char) -> *mut c_void {
+            let error = unsafe { CStr::from_ptr(error) };
+            Box::into_raw(Box::new(io::Error::new(
+                io::ErrorKind::Other,
+                format!("LLVM error: {}", error.to_string_lossy()),
+            ))) as *mut c_void
+        }
+    } else {
+        get_native_object_symbols(buf, f)
     }
+}
+
+impl<'a> LlvmArchiveBuilder<'a> {
+    fn build_with_llvm(&mut self, output: &Path) -> io::Result<bool> {
+        let kind = &*self.sess.target.archive_format;
+        let kind = kind
+            .parse::<ArchiveKind>()
+            .map_err(|_| kind)
+            .unwrap_or_else(|kind| self.sess.emit_fatal(UnknownArchiveKind { kind }));
 
-    fn build_with_llvm(&mut self, kind: ArchiveKind) -> io::Result<()> {
-        let removals = mem::take(&mut self.removals);
         let mut additions = mem::take(&mut self.additions);
         let mut strings = Vec::new();
         let mut members = Vec::new();
 
-        let dst = CString::new(self.config.dst.to_str().unwrap())?;
+        let dst = CString::new(output.to_str().unwrap())?;
 
         unsafe {
-            if let Some(archive) = self.src_archive() {
-                for child in archive.iter() {
-                    let child = child.map_err(string_to_io_error)?;
-                    let Some(child_name) = child.name() else { continue };
-                    if removals.iter().any(|r| r == child_name) {
-                        continue;
-                    }
-
-                    let name = CString::new(child_name)?;
-                    members.push(llvm::LLVMRustArchiveMemberNew(
-                        ptr::null(),
-                        name.as_ptr(),
-                        Some(child.raw),
-                    ));
-                    strings.push(name);
-                }
-            }
             for addition in &mut additions {
                 match addition {
                     Addition::File { path, name_in_archive } => {
@@ -389,7 +392,7 @@ impl<'a> LlvmArchiveBuilder<'a> {
                 };
                 Err(io::Error::new(io::ErrorKind::Other, msg))
             } else {
-                Ok(())
+                Ok(!members.is_empty())
             };
             for member in members {
                 llvm::LLVMRustArchiveMemberFree(member);
@@ -397,22 +400,6 @@ impl<'a> LlvmArchiveBuilder<'a> {
             ret
         }
     }
-
-    fn i686_decorated_name(import: &DllImport, mingw: bool) -> String {
-        let name = import.name;
-        let prefix = if mingw { "" } else { "_" };
-
-        match import.calling_convention {
-            DllCallingConvention::C => format!("{}{}", prefix, name),
-            DllCallingConvention::Stdcall(arg_list_size) => {
-                format!("{}{}@{}", prefix, name, arg_list_size)
-            }
-            DllCallingConvention::Fastcall(arg_list_size) => format!("@{}@{}", name, arg_list_size),
-            DllCallingConvention::Vectorcall(arg_list_size) => {
-                format!("{}@@{}", name, arg_list_size)
-            }
-        }
-    }
 }
 
 fn string_to_io_error(s: String) -> io::Error {
@@ -421,7 +408,7 @@ fn string_to_io_error(s: String) -> io::Error {
 
 fn find_binutils_dlltool(sess: &Session) -> OsString {
     assert!(sess.target.options.is_like_windows && !sess.target.options.is_like_msvc);
-    if let Some(dlltool_path) = &sess.opts.debugging_opts.dlltool {
+    if let Some(dlltool_path) = &sess.opts.unstable_opts.dlltool {
         return dlltool_path.clone().into_os_string();
     }
 
diff --git a/compiler/rustc_codegen_llvm/src/back/lto.rs b/compiler/rustc_codegen_llvm/src/back/lto.rs
index 38402e04313..3fa21355b7f 100644
--- a/compiler/rustc_codegen_llvm/src/back/lto.rs
+++ b/compiler/rustc_codegen_llvm/src/back/lto.rs
@@ -1,15 +1,15 @@
-use crate::back::write::{
-    self, save_temp_bitcode, to_llvm_opt_settings, with_llvm_pmb, DiagnosticHandlers,
-};
-use crate::llvm::archive_ro::ArchiveRO;
-use crate::llvm::{self, build_string, False, True};
-use crate::{llvm_util, LlvmCodegenBackend, ModuleLlvm};
+use crate::back::write::{self, save_temp_bitcode, DiagnosticHandlers};
+use crate::errors::DynamicLinkingWithLTO;
+use crate::llvm::{self, build_string};
+use crate::{LlvmCodegenBackend, ModuleLlvm};
+use object::read::archive::ArchiveFile;
 use rustc_codegen_ssa::back::lto::{LtoModuleCodegen, SerializedModule, ThinModule, ThinShared};
 use rustc_codegen_ssa::back::symbol_export;
 use rustc_codegen_ssa::back::write::{CodegenContext, FatLTOInput, TargetMachineFactoryConfig};
 use rustc_codegen_ssa::traits::*;
 use rustc_codegen_ssa::{looks_like_rust_object_file, ModuleCodegen, ModuleKind};
 use rustc_data_structures::fx::FxHashMap;
+use rustc_data_structures::memmap::Mmap;
 use rustc_errors::{FatalError, Handler};
 use rustc_hir::def_id::LOCAL_CRATE;
 use rustc_middle::bug;
@@ -17,7 +17,6 @@ use rustc_middle::dep_graph::WorkProduct;
 use rustc_middle::middle::exported_symbols::{SymbolExportInfo, SymbolExportLevel};
 use rustc_session::cgu_reuse_tracker::CguReuse;
 use rustc_session::config::{self, CrateType, Lto};
-use tracing::{debug, info};
 
 use std::ffi::{CStr, CString};
 use std::fs::File;
@@ -34,8 +33,8 @@ pub const THIN_LTO_KEYS_INCR_COMP_FILE_NAME: &str = "thin-lto-past-keys.bin";
 
 pub fn crate_type_allows_lto(crate_type: CrateType) -> bool {
     match crate_type {
-        CrateType::Executable | CrateType::Staticlib | CrateType::Cdylib => true,
-        CrateType::Dylib | CrateType::Rlib | CrateType::ProcMacro => false,
+        CrateType::Executable | CrateType::Dylib | CrateType::Staticlib | CrateType::Cdylib => true,
+        CrateType::Rlib | CrateType::ProcMacro => false,
     }
 }
 
@@ -75,17 +74,6 @@ fn prepare_lto(
     // with either fat or thin LTO
     let mut upstream_modules = Vec::new();
     if cgcx.lto != Lto::ThinLocal {
-        if cgcx.opts.cg.prefer_dynamic {
-            diag_handler
-                .struct_err("cannot prefer dynamic linking when performing LTO")
-                .note(
-                    "only 'staticlib', 'bin', and 'cdylib' outputs are \
-                               supported with LTO",
-                )
-                .emit();
-            return Err(FatalError);
-        }
-
         // Make sure we actually can run LTO
         for crate_type in cgcx.crate_types.iter() {
             if !crate_type_allows_lto(*crate_type) {
@@ -94,9 +82,19 @@ fn prepare_lto(
                                             static library outputs",
                 );
                 return Err(e);
+            } else if *crate_type == CrateType::Dylib {
+                if !cgcx.opts.unstable_opts.dylib_lto {
+                    return Err(diag_handler
+                        .fatal("lto cannot be used for `dylib` crate type without `-Zdylib-lto`"));
+                }
             }
         }
 
+        if cgcx.opts.cg.prefer_dynamic && !cgcx.opts.unstable_opts.dylib_lto {
+            diag_handler.emit_err(DynamicLinkingWithLTO);
+            return Err(FatalError);
+        }
+
         for &(cnum, ref path) in cgcx.each_linked_rlib_for_lto.iter() {
             let exported_symbols =
                 cgcx.exported_symbols.as_ref().expect("needs exported symbols for LTO");
@@ -107,14 +105,24 @@ fn prepare_lto(
                     .extend(exported_symbols[&cnum].iter().filter_map(symbol_filter));
             }
 
-            let archive = ArchiveRO::open(path).expect("wanted an rlib");
+            let archive_data = unsafe {
+                Mmap::map(std::fs::File::open(&path).expect("couldn't open rlib"))
+                    .expect("couldn't map rlib")
+            };
+            let archive = ArchiveFile::parse(&*archive_data).expect("wanted an rlib");
             let obj_files = archive
-                .iter()
-                .filter_map(|child| child.ok().and_then(|c| c.name().map(|name| (name, c))))
+                .members()
+                .filter_map(|child| {
+                    child.ok().and_then(|c| {
+                        std::str::from_utf8(c.name()).ok().map(|name| (name.trim(), c))
+                    })
+                })
                 .filter(|&(name, _)| looks_like_rust_object_file(name));
             for (name, child) in obj_files {
                 info!("adding bitcode from {}", name);
-                match get_bitcode_slice_from_object_data(child.data()) {
+                match get_bitcode_slice_from_object_data(
+                    child.data(&*archive_data).expect("corrupt rlib"),
+                ) {
                     Ok(data) => {
                         let module = SerializedModule::FromRlib(data.to_vec());
                         upstream_modules.push((module, CString::new(name).unwrap()));
@@ -199,7 +207,7 @@ pub(crate) fn run_thin(
 
 pub(crate) fn prepare_thin(module: ModuleCodegen<ModuleLlvm>) -> (String, ThinBuffer) {
     let name = module.name.clone();
-    let buffer = ThinBuffer::new(module.module_llvm.llmod());
+    let buffer = ThinBuffer::new(module.module_llvm.llmod(), true);
     (name, buffer)
 }
 
@@ -325,20 +333,6 @@ fn fat_lto(
         drop(linker);
         save_temp_bitcode(cgcx, &module, "lto.input");
 
-        // Fat LTO also suffers from the invalid DWARF issue similar to Thin LTO.
-        // Here we rewrite all `DICompileUnit` pointers if there is only one `DICompileUnit`.
-        // This only works around the problem when codegen-units = 1.
-        // Refer to the comments in the `optimize_thin_module` function for more details.
-        let mut cu1 = ptr::null_mut();
-        let mut cu2 = ptr::null_mut();
-        unsafe { llvm::LLVMRustLTOGetDICompileUnit(llmod, &mut cu1, &mut cu2) };
-        if !cu2.is_null() {
-            let _timer =
-                cgcx.prof.generic_activity_with_arg("LLVM_fat_lto_patch_debuginfo", &*module.name);
-            unsafe { llvm::LLVMRustLTOPatchDICompileUnit(llmod, cu1) };
-            save_temp_bitcode(cgcx, &module, "fat-lto-after-patch");
-        }
-
         // Internalize everything below threshold to help strip out more modules and such.
         unsafe {
             let ptr = symbols_below_threshold.as_ptr();
@@ -579,7 +573,7 @@ pub(crate) fn run_pass_manager(
     module: &mut ModuleCodegen<ModuleLlvm>,
     thin: bool,
 ) -> Result<(), FatalError> {
-    let _timer = cgcx.prof.extra_verbose_generic_activity("LLVM_lto_optimize", &*module.name);
+    let _timer = cgcx.prof.verbose_generic_activity_with_arg("LLVM_lto_optimize", &*module.name);
     let config = cgcx.config(module.kind);
 
     // Now we have one massive module inside of llmod. Time to run the
@@ -601,61 +595,9 @@ pub(crate) fn run_pass_manager(
                 1,
             );
         }
-        if llvm_util::should_use_new_llvm_pass_manager(
-            &config.new_llvm_pass_manager,
-            &cgcx.target_arch,
-        ) {
-            let opt_stage = if thin { llvm::OptStage::ThinLTO } else { llvm::OptStage::FatLTO };
-            let opt_level = config.opt_level.unwrap_or(config::OptLevel::No);
-            write::optimize_with_new_llvm_pass_manager(
-                cgcx,
-                diag_handler,
-                module,
-                config,
-                opt_level,
-                opt_stage,
-            )?;
-            debug!("lto done");
-            return Ok(());
-        }
-
-        let pm = llvm::LLVMCreatePassManager();
-        llvm::LLVMAddAnalysisPasses(module.module_llvm.tm, pm);
-
-        if config.verify_llvm_ir {
-            let pass = llvm::LLVMRustFindAndCreatePass("verify\0".as_ptr().cast());
-            llvm::LLVMRustAddPass(pm, pass.unwrap());
-        }
-
-        let opt_level = config
-            .opt_level
-            .map(|x| to_llvm_opt_settings(x).0)
-            .unwrap_or(llvm::CodeGenOptLevel::None);
-        with_llvm_pmb(module.module_llvm.llmod(), config, opt_level, false, &mut |b| {
-            if thin {
-                llvm::LLVMRustPassManagerBuilderPopulateThinLTOPassManager(b, pm);
-            } else {
-                llvm::LLVMRustPassManagerBuilderPopulateLTOPassManager(
-                    b, pm, /* Internalize = */ False, /* RunInliner = */ True,
-                );
-            }
-        });
-
-        // We always generate bitcode through ThinLTOBuffers,
-        // which do not support anonymous globals
-        if config.bitcode_needed() {
-            let pass = llvm::LLVMRustFindAndCreatePass("name-anon-globals\0".as_ptr().cast());
-            llvm::LLVMRustAddPass(pm, pass.unwrap());
-        }
-
-        if config.verify_llvm_ir {
-            let pass = llvm::LLVMRustFindAndCreatePass("verify\0".as_ptr().cast());
-            llvm::LLVMRustAddPass(pm, pass.unwrap());
-        }
-
-        llvm::LLVMRunPassManager(pm, module.module_llvm.llmod());
-
-        llvm::LLVMDisposePassManager(pm);
+        let opt_stage = if thin { llvm::OptStage::ThinLTO } else { llvm::OptStage::FatLTO };
+        let opt_level = config.opt_level.unwrap_or(config::OptLevel::No);
+        write::llvm_optimize(cgcx, diag_handler, module, config, opt_level, opt_stage)?;
     }
     debug!("lto done");
     Ok(())
@@ -709,9 +651,9 @@ unsafe impl Send for ThinBuffer {}
 unsafe impl Sync for ThinBuffer {}
 
 impl ThinBuffer {
-    pub fn new(m: &llvm::Module) -> ThinBuffer {
+    pub fn new(m: &llvm::Module, is_thin: bool) -> ThinBuffer {
         unsafe {
-            let buffer = llvm::LLVMRustThinLTOBufferCreate(m);
+            let buffer = llvm::LLVMRustThinLTOBufferCreate(m, is_thin);
             ThinBuffer(buffer)
         }
     }
@@ -769,7 +711,7 @@ pub unsafe fn optimize_thin_module(
         // an error.
         let mut cu1 = ptr::null_mut();
         let mut cu2 = ptr::null_mut();
-        llvm::LLVMRustLTOGetDICompileUnit(llmod, &mut cu1, &mut cu2);
+        llvm::LLVMRustThinLTOGetDICompileUnit(llmod, &mut cu1, &mut cu2);
         if !cu2.is_null() {
             let msg = "multiple source DICompileUnits found";
             return Err(write::llvm_err(&diag_handler, msg));
@@ -858,7 +800,7 @@ pub unsafe fn optimize_thin_module(
             let _timer = cgcx
                 .prof
                 .generic_activity_with_arg("LLVM_thin_lto_patch_debuginfo", thin_module.name());
-            llvm::LLVMRustLTOPatchDICompileUnit(llmod, cu1);
+            llvm::LLVMRustThinLTOPatchDICompileUnit(llmod, cu1);
             save_temp_bitcode(cgcx, &module, "thin-lto-after-patch");
         }
 
diff --git a/compiler/rustc_codegen_llvm/src/back/write.rs b/compiler/rustc_codegen_llvm/src/back/write.rs
index ab8874d796d..97d0de47b3a 100644
--- a/compiler/rustc_codegen_llvm/src/back/write.rs
+++ b/compiler/rustc_codegen_llvm/src/back/write.rs
@@ -5,7 +5,7 @@ use crate::back::profiling::{
 use crate::base;
 use crate::common;
 use crate::consts;
-use crate::llvm::{self, DiagnosticInfo, PassManager, SMDiagnostic};
+use crate::llvm::{self, DiagnosticInfo, PassManager};
 use crate::llvm_util;
 use crate::type_::Type;
 use crate::LlvmCodegenBackend;
@@ -21,14 +21,12 @@ use rustc_data_structures::profiling::SelfProfilerRef;
 use rustc_data_structures::small_c_str::SmallCStr;
 use rustc_errors::{FatalError, Handler, Level};
 use rustc_fs_util::{link_or_copy, path_to_c_string};
-use rustc_middle::bug;
 use rustc_middle::ty::TyCtxt;
 use rustc_session::config::{self, Lto, OutputType, Passes, SplitDwarfKind, SwitchWithOptPath};
 use rustc_session::Session;
 use rustc_span::symbol::sym;
 use rustc_span::InnerSpan;
 use rustc_target::spec::{CodeModel, RelocModel, SanitizerSet, SplitDebuginfo};
-use tracing::debug;
 
 use libc::{c_char, c_int, c_uint, c_void, size_t};
 use std::ffi::CString;
@@ -107,7 +105,7 @@ pub fn create_target_machine(tcx: TyCtxt<'_>, mod_name: &str) -> &'static mut ll
     let split_dwarf_file = if tcx.sess.target_can_use_split_dwarf() {
         tcx.output_filenames(()).split_dwarf_path(
             tcx.sess.split_debuginfo(),
-            tcx.sess.opts.debugging_opts.split_dwarf_kind,
+            tcx.sess.opts.unstable_opts.split_dwarf_kind,
             Some(mod_name),
         )
     } else {
@@ -182,9 +180,9 @@ pub fn target_machine_factory(
     let use_softfp = sess.opts.cg.soft_float;
 
     let ffunction_sections =
-        sess.opts.debugging_opts.function_sections.unwrap_or(sess.target.function_sections);
+        sess.opts.unstable_opts.function_sections.unwrap_or(sess.target.function_sections);
     let fdata_sections = ffunction_sections;
-    let funique_section_names = !sess.opts.debugging_opts.no_unique_section_names;
+    let funique_section_names = !sess.opts.unstable_opts.no_unique_section_names;
 
     let code_model = to_llvm_code_model(sess.code_model());
 
@@ -202,15 +200,15 @@ pub fn target_machine_factory(
     let features = CString::new(target_features.join(",")).unwrap();
     let abi = SmallCStr::new(&sess.target.llvm_abiname);
     let trap_unreachable =
-        sess.opts.debugging_opts.trap_unreachable.unwrap_or(sess.target.trap_unreachable);
-    let emit_stack_size_section = sess.opts.debugging_opts.emit_stack_sizes;
+        sess.opts.unstable_opts.trap_unreachable.unwrap_or(sess.target.trap_unreachable);
+    let emit_stack_size_section = sess.opts.unstable_opts.emit_stack_sizes;
 
     let asm_comments = sess.asm_comments();
     let relax_elf_relocations =
-        sess.opts.debugging_opts.relax_elf_relocations.unwrap_or(sess.target.relax_elf_relocations);
+        sess.opts.unstable_opts.relax_elf_relocations.unwrap_or(sess.target.relax_elf_relocations);
 
     let use_init_array =
-        !sess.opts.debugging_opts.use_ctors_section.unwrap_or(sess.target.use_ctors_section);
+        !sess.opts.unstable_opts.use_ctors_section.unwrap_or(sess.target.use_ctors_section);
 
     let path_mapping = sess.source_map().path_mapping().clone();
 
@@ -304,7 +302,6 @@ impl<'a> DiagnosticHandlers<'a> {
                 remark_passes.as_ptr(),
                 remark_passes.len(),
             );
-            llvm::LLVMRustSetInlineAsmDiagnosticHandler(llcx, inline_asm_handler, data.cast());
             DiagnosticHandlers { data, llcx, old_handler }
         }
     }
@@ -312,9 +309,7 @@ impl<'a> DiagnosticHandlers<'a> {
 
 impl<'a> Drop for DiagnosticHandlers<'a> {
     fn drop(&mut self) {
-        use std::ptr::null_mut;
         unsafe {
-            llvm::LLVMRustSetInlineAsmDiagnosticHandler(self.llcx, inline_asm_handler, null_mut());
             llvm::LLVMRustContextSetDiagnosticHandler(self.llcx, self.old_handler);
             drop(Box::from_raw(self.data));
         }
@@ -342,16 +337,6 @@ fn report_inline_asm(
     cgcx.diag_emitter.inline_asm_error(cookie as u32, msg, level, source);
 }
 
-unsafe extern "C" fn inline_asm_handler(diag: &SMDiagnostic, user: *const c_void, cookie: c_uint) {
-    if user.is_null() {
-        return;
-    }
-    let (cgcx, _) = *(user as *const (&CodegenContext<LlvmCodegenBackend>, &Handler));
-
-    let smdiag = llvm::diagnostic::SrcMgrDiagnostic::unpack(diag);
-    report_inline_asm(cgcx, smdiag.message, smdiag.level, cookie, smdiag.source);
-}
-
 unsafe extern "C" fn diagnostic_handler(info: &DiagnosticInfo, user: *mut c_void) {
     if user.is_null() {
         return;
@@ -423,7 +408,15 @@ fn get_pgo_sample_use_path(config: &ModuleConfig) -> Option<CString> {
         .map(|path_buf| CString::new(path_buf.to_string_lossy().as_bytes()).unwrap())
 }
 
-pub(crate) unsafe fn optimize_with_new_llvm_pass_manager(
+fn get_instr_profile_output_path(config: &ModuleConfig) -> Option<CString> {
+    if config.instrument_coverage {
+        Some(CString::new("default_%m_%p.profraw").unwrap())
+    } else {
+        None
+    }
+}
+
+pub(crate) unsafe fn llvm_optimize(
     cgcx: &CodegenContext<LlvmCodegenBackend>,
     diag_handler: &Handler,
     module: &ModuleCodegen<ModuleLlvm>,
@@ -438,6 +431,7 @@ pub(crate) unsafe fn optimize_with_new_llvm_pass_manager(
     let pgo_use_path = get_pgo_use_path(config);
     let pgo_sample_use_path = get_pgo_sample_use_path(config);
     let is_lto = opt_stage == llvm::OptStage::ThinLTO || opt_stage == llvm::OptStage::FatLTO;
+    let instr_profile_output_path = get_instr_profile_output_path(config);
     // Sanitizer instrumentation is only inserted during the pre-link optimization stage.
     let sanitizer_options = if !is_lto {
         Some(llvm::SanitizerOptions {
@@ -470,7 +464,7 @@ pub(crate) unsafe fn optimize_with_new_llvm_pass_manager(
     // FIXME: NewPM doesn't provide a facility to pass custom InlineParams.
     // We would have to add upstream support for this first, before we can support
     // config.inline_threshold and our more aggressive default thresholds.
-    let result = llvm::LLVMRustOptimizeWithNewPassManager(
+    let result = llvm::LLVMRustOptimize(
         module.module_llvm.llmod(),
         &*module.module_llvm.tm,
         to_pass_builder_opt_level(opt_level),
@@ -488,6 +482,7 @@ pub(crate) unsafe fn optimize_with_new_llvm_pass_manager(
         pgo_gen_path.as_ref().map_or(std::ptr::null(), |s| s.as_ptr()),
         pgo_use_path.as_ref().map_or(std::ptr::null(), |s| s.as_ptr()),
         config.instrument_coverage,
+        instr_profile_output_path.as_ref().map_or(std::ptr::null(), |s| s.as_ptr()),
         config.instrument_gcov,
         pgo_sample_use_path.as_ref().map_or(std::ptr::null(), |s| s.as_ptr()),
         config.debug_info_for_profiling,
@@ -513,18 +508,11 @@ pub(crate) unsafe fn optimize(
 
     let llmod = module.module_llvm.llmod();
     let llcx = &*module.module_llvm.llcx;
-    let tm = &*module.module_llvm.tm;
     let _handlers = DiagnosticHandlers::new(cgcx, diag_handler, llcx);
 
     let module_name = module.name.clone();
     let module_name = Some(&module_name[..]);
 
-    if let Some(false) = config.new_llvm_pass_manager && llvm_util::get_version() >= (15, 0, 0) {
-        diag_handler.warn(
-            "ignoring `-Z new-llvm-pass-manager=no`, which is no longer supported with LLVM 15",
-        );
-    }
-
     if config.emit_no_opt_bc {
         let out = cgcx.output_filenames.temp_path_ext("no-opt.bc", module_name);
         let out = path_to_c_string(&out);
@@ -532,191 +520,24 @@ pub(crate) unsafe fn optimize(
     }
 
     if let Some(opt_level) = config.opt_level {
-        if llvm_util::should_use_new_llvm_pass_manager(
-            &config.new_llvm_pass_manager,
-            &cgcx.target_arch,
-        ) {
-            let opt_stage = match cgcx.lto {
-                Lto::Fat => llvm::OptStage::PreLinkFatLTO,
-                Lto::Thin | Lto::ThinLocal => llvm::OptStage::PreLinkThinLTO,
-                _ if cgcx.opts.cg.linker_plugin_lto.enabled() => llvm::OptStage::PreLinkThinLTO,
-                _ => llvm::OptStage::PreLinkNoLTO,
-            };
-            return optimize_with_new_llvm_pass_manager(
-                cgcx,
-                diag_handler,
-                module,
-                config,
-                opt_level,
-                opt_stage,
-            );
-        }
-
-        if cgcx.prof.llvm_recording_enabled() {
-            diag_handler
-                .warn("`-Z self-profile-events = llvm` requires `-Z new-llvm-pass-manager`");
-        }
-
-        // Create the two optimizing pass managers. These mirror what clang
-        // does, and are by populated by LLVM's default PassManagerBuilder.
-        // Each manager has a different set of passes, but they also share
-        // some common passes.
-        let fpm = llvm::LLVMCreateFunctionPassManagerForModule(llmod);
-        let mpm = llvm::LLVMCreatePassManager();
-
-        {
-            let find_pass = |pass_name: &str| {
-                let pass_name = SmallCStr::new(pass_name);
-                llvm::LLVMRustFindAndCreatePass(pass_name.as_ptr())
-            };
-
-            if config.verify_llvm_ir {
-                // Verification should run as the very first pass.
-                llvm::LLVMRustAddPass(fpm, find_pass("verify").unwrap());
-            }
-
-            let mut extra_passes = Vec::new();
-            let mut have_name_anon_globals_pass = false;
-
-            for pass_name in &config.passes {
-                if pass_name == "lint" {
-                    // Linting should also be performed early, directly on the generated IR.
-                    llvm::LLVMRustAddPass(fpm, find_pass("lint").unwrap());
-                    continue;
-                }
-
-                if let Some(pass) = find_pass(pass_name) {
-                    extra_passes.push(pass);
-                } else {
-                    diag_handler.warn(&format!("unknown pass `{}`, ignoring", pass_name));
-                }
-
-                if pass_name == "name-anon-globals" {
-                    have_name_anon_globals_pass = true;
-                }
-            }
-
-            // Instrumentation must be inserted before optimization,
-            // otherwise LLVM may optimize some functions away which
-            // breaks llvm-cov.
-            //
-            // This mirrors what Clang does in lib/CodeGen/BackendUtil.cpp.
-            if config.instrument_gcov {
-                llvm::LLVMRustAddPass(mpm, find_pass("insert-gcov-profiling").unwrap());
-            }
-            if config.instrument_coverage {
-                llvm::LLVMRustAddPass(mpm, find_pass("instrprof").unwrap());
-            }
-            if config.debug_info_for_profiling {
-                llvm::LLVMRustAddPass(mpm, find_pass("add-discriminators").unwrap());
-            }
-
-            add_sanitizer_passes(config, &mut extra_passes);
-
-            // Some options cause LLVM bitcode to be emitted, which uses ThinLTOBuffers, so we need
-            // to make sure we run LLVM's NameAnonGlobals pass when emitting bitcode; otherwise
-            // we'll get errors in LLVM.
-            let using_thin_buffers = config.bitcode_needed();
-            if !config.no_prepopulate_passes {
-                llvm::LLVMAddAnalysisPasses(tm, fpm);
-                llvm::LLVMAddAnalysisPasses(tm, mpm);
-                let opt_level = to_llvm_opt_settings(opt_level).0;
-                let prepare_for_thin_lto = cgcx.lto == Lto::Thin
-                    || cgcx.lto == Lto::ThinLocal
-                    || (cgcx.lto != Lto::Fat && cgcx.opts.cg.linker_plugin_lto.enabled());
-                with_llvm_pmb(llmod, config, opt_level, prepare_for_thin_lto, &mut |b| {
-                    llvm::LLVMRustAddLastExtensionPasses(
-                        b,
-                        extra_passes.as_ptr(),
-                        extra_passes.len() as size_t,
-                    );
-                    llvm::LLVMRustPassManagerBuilderPopulateFunctionPassManager(b, fpm);
-                    llvm::LLVMRustPassManagerBuilderPopulateModulePassManager(b, mpm);
-                });
-
-                have_name_anon_globals_pass = have_name_anon_globals_pass || prepare_for_thin_lto;
-                if using_thin_buffers && !prepare_for_thin_lto {
-                    llvm::LLVMRustAddPass(mpm, find_pass("name-anon-globals").unwrap());
-                    have_name_anon_globals_pass = true;
-                }
-            } else {
-                // If we don't use the standard pipeline, directly populate the MPM
-                // with the extra passes.
-                for pass in extra_passes {
-                    llvm::LLVMRustAddPass(mpm, pass);
-                }
-            }
-
-            if using_thin_buffers && !have_name_anon_globals_pass {
-                // As described above, this will probably cause an error in LLVM
-                if config.no_prepopulate_passes {
-                    diag_handler.err(
-                        "The current compilation is going to use thin LTO buffers \
-                                      without running LLVM's NameAnonGlobals pass. \
-                                      This will likely cause errors in LLVM. Consider adding \
-                                      -C passes=name-anon-globals to the compiler command line.",
-                    );
-                } else {
-                    bug!(
-                        "We are using thin LTO buffers without running the NameAnonGlobals pass. \
-                          This will likely cause errors in LLVM and should never happen."
-                    );
-                }
-            }
-        }
-
-        diag_handler.abort_if_errors();
-
-        // Finally, run the actual optimization passes
-        {
-            let _timer = cgcx.prof.extra_verbose_generic_activity(
-                "LLVM_module_optimize_function_passes",
-                &*module.name,
-            );
-            llvm::LLVMRustRunFunctionPassManager(fpm, llmod);
-        }
-        {
-            let _timer = cgcx.prof.extra_verbose_generic_activity(
-                "LLVM_module_optimize_module_passes",
-                &*module.name,
-            );
-            llvm::LLVMRunPassManager(mpm, llmod);
-        }
-
-        // Deallocate managers that we're now done with
-        llvm::LLVMDisposePassManager(fpm);
-        llvm::LLVMDisposePassManager(mpm);
+        let opt_stage = match cgcx.lto {
+            Lto::Fat => llvm::OptStage::PreLinkFatLTO,
+            Lto::Thin | Lto::ThinLocal => llvm::OptStage::PreLinkThinLTO,
+            _ if cgcx.opts.cg.linker_plugin_lto.enabled() => llvm::OptStage::PreLinkThinLTO,
+            _ => llvm::OptStage::PreLinkNoLTO,
+        };
+        return llvm_optimize(cgcx, diag_handler, module, config, opt_level, opt_stage);
     }
     Ok(())
 }
 
-unsafe fn add_sanitizer_passes(config: &ModuleConfig, passes: &mut Vec<&'static mut llvm::Pass>) {
-    if config.sanitizer.contains(SanitizerSet::ADDRESS) {
-        let recover = config.sanitizer_recover.contains(SanitizerSet::ADDRESS);
-        passes.push(llvm::LLVMRustCreateAddressSanitizerFunctionPass(recover));
-        passes.push(llvm::LLVMRustCreateModuleAddressSanitizerPass(recover));
-    }
-    if config.sanitizer.contains(SanitizerSet::MEMORY) {
-        let track_origins = config.sanitizer_memory_track_origins as c_int;
-        let recover = config.sanitizer_recover.contains(SanitizerSet::MEMORY);
-        passes.push(llvm::LLVMRustCreateMemorySanitizerPass(track_origins, recover));
-    }
-    if config.sanitizer.contains(SanitizerSet::THREAD) {
-        passes.push(llvm::LLVMRustCreateThreadSanitizerPass());
-    }
-    if config.sanitizer.contains(SanitizerSet::HWADDRESS) {
-        let recover = config.sanitizer_recover.contains(SanitizerSet::HWADDRESS);
-        passes.push(llvm::LLVMRustCreateHWAddressSanitizerPass(recover));
-    }
-}
-
 pub(crate) fn link(
     cgcx: &CodegenContext<LlvmCodegenBackend>,
     diag_handler: &Handler,
     mut modules: Vec<ModuleCodegen<ModuleLlvm>>,
 ) -> Result<ModuleCodegen<ModuleLlvm>, FatalError> {
     use super::lto::{Linker, ModuleBuffer};
-    // Sort the modules by name to ensure to ensure deterministic behavior.
+    // Sort the modules by name to ensure deterministic behavior.
     modules.sort_by(|a, b| a.name.cmp(&b.name));
     let (first, elements) =
         modules.split_first().expect("Bug! modules must contain at least one module.");
@@ -790,7 +611,7 @@ pub(crate) unsafe fn codegen(
             let _timer = cgcx
                 .prof
                 .generic_activity_with_arg("LLVM_module_codegen_make_bitcode", &*module.name);
-            let thin = ThinBuffer::new(llmod);
+            let thin = ThinBuffer::new(llmod, config.emit_thin_lto);
             let data = thin.data();
 
             if let Some(bitcode_filename) = bc_out.file_name() {
@@ -944,11 +765,21 @@ pub(crate) unsafe fn codegen(
         drop(handlers);
     }
 
+    // `.dwo` files are only emitted if:
+    //
+    // - Object files are being emitted (i.e. bitcode only or metadata only compilations will not
+    //   produce dwarf objects, even if otherwise enabled)
+    // - Target supports Split DWARF
+    // - Split debuginfo is enabled
+    // - Split DWARF kind is `split` (i.e. debuginfo is split into `.dwo` files, not different
+    //   sections in the `.o` files).
+    let dwarf_object_emitted = matches!(config.emit_obj, EmitObj::ObjectCode(_))
+        && cgcx.target_can_use_split_dwarf
+        && cgcx.split_debuginfo != SplitDebuginfo::Off
+        && cgcx.split_dwarf_kind == SplitDwarfKind::Split;
     Ok(module.into_compiled_module(
         config.emit_obj != EmitObj::None,
-        cgcx.target_can_use_split_dwarf
-            && cgcx.split_debuginfo != SplitDebuginfo::Off
-            && cgcx.split_dwarf_kind == SplitDwarfKind::Split,
+        dwarf_object_emitted,
         config.emit_bc,
         &cgcx.output_filenames,
     ))
@@ -1076,72 +907,6 @@ unsafe fn embed_bitcode(
     }
 }
 
-pub unsafe fn with_llvm_pmb(
-    llmod: &llvm::Module,
-    config: &ModuleConfig,
-    opt_level: llvm::CodeGenOptLevel,
-    prepare_for_thin_lto: bool,
-    f: &mut dyn FnMut(&llvm::PassManagerBuilder),
-) {
-    use std::ptr;
-
-    // Create the PassManagerBuilder for LLVM. We configure it with
-    // reasonable defaults and prepare it to actually populate the pass
-    // manager.
-    let builder = llvm::LLVMRustPassManagerBuilderCreate();
-    let opt_size = config.opt_size.map_or(llvm::CodeGenOptSizeNone, |x| to_llvm_opt_settings(x).1);
-    let inline_threshold = config.inline_threshold;
-    let pgo_gen_path = get_pgo_gen_path(config);
-    let pgo_use_path = get_pgo_use_path(config);
-    let pgo_sample_use_path = get_pgo_sample_use_path(config);
-
-    llvm::LLVMRustConfigurePassManagerBuilder(
-        builder,
-        opt_level,
-        config.merge_functions,
-        config.vectorize_slp,
-        config.vectorize_loop,
-        prepare_for_thin_lto,
-        pgo_gen_path.as_ref().map_or(ptr::null(), |s| s.as_ptr()),
-        pgo_use_path.as_ref().map_or(ptr::null(), |s| s.as_ptr()),
-        pgo_sample_use_path.as_ref().map_or(ptr::null(), |s| s.as_ptr()),
-        opt_size as c_int,
-    );
-
-    llvm::LLVMRustAddBuilderLibraryInfo(builder, llmod, config.no_builtins);
-
-    // Here we match what clang does (kinda). For O0 we only inline
-    // always-inline functions (but don't add lifetime intrinsics), at O1 we
-    // inline with lifetime intrinsics, and O2+ we add an inliner with a
-    // thresholds copied from clang.
-    match (opt_level, opt_size, inline_threshold) {
-        (.., Some(t)) => {
-            llvm::LLVMRustPassManagerBuilderUseInlinerWithThreshold(builder, t);
-        }
-        (llvm::CodeGenOptLevel::Aggressive, ..) => {
-            llvm::LLVMRustPassManagerBuilderUseInlinerWithThreshold(builder, 275);
-        }
-        (_, llvm::CodeGenOptSizeDefault, _) => {
-            llvm::LLVMRustPassManagerBuilderUseInlinerWithThreshold(builder, 75);
-        }
-        (_, llvm::CodeGenOptSizeAggressive, _) => {
-            llvm::LLVMRustPassManagerBuilderUseInlinerWithThreshold(builder, 25);
-        }
-        (llvm::CodeGenOptLevel::None, ..) => {
-            llvm::LLVMRustAddAlwaysInlinePass(builder, config.emit_lifetime_markers);
-        }
-        (llvm::CodeGenOptLevel::Less, ..) => {
-            llvm::LLVMRustAddAlwaysInlinePass(builder, config.emit_lifetime_markers);
-        }
-        (llvm::CodeGenOptLevel::Default, ..) => {
-            llvm::LLVMRustPassManagerBuilderUseInlinerWithThreshold(builder, 225);
-        }
-    }
-
-    f(builder);
-    llvm::LLVMRustPassManagerBuilderDispose(builder);
-}
-
 // Create a `__imp_<symbol> = &symbol` global for every public static `symbol`.
 // This is required to satisfy `dllimport` references to static data in .rlibs
 // when using MSVC linker.  We do this only for data, as linker can fix up
diff --git a/compiler/rustc_codegen_llvm/src/base.rs b/compiler/rustc_codegen_llvm/src/base.rs
index 86f92dc0239..5b2bbdb4bde 100644
--- a/compiler/rustc_codegen_llvm/src/base.rs
+++ b/compiler/rustc_codegen_llvm/src/base.rs
@@ -19,6 +19,8 @@ use crate::context::CodegenCx;
 use crate::llvm;
 use crate::value::Value;
 
+use cstr::cstr;
+
 use rustc_codegen_ssa::base::maybe_create_entry_wrapper;
 use rustc_codegen_ssa::mono_item::MonoItemExt;
 use rustc_codegen_ssa::traits::*;
@@ -107,11 +109,14 @@ pub fn compile_codegen_unit(tcx: TyCtxt<'_>, cgu_name: Symbol) -> (ModuleCodegen
             }
 
             // Create the llvm.used and llvm.compiler.used variables.
-            if !cx.used_statics().borrow().is_empty() {
-                cx.create_used_variable()
+            if !cx.used_statics.borrow().is_empty() {
+                cx.create_used_variable_impl(cstr!("llvm.used"), &*cx.used_statics.borrow());
             }
-            if !cx.compiler_used_statics().borrow().is_empty() {
-                cx.create_compiler_used_variable()
+            if !cx.compiler_used_statics.borrow().is_empty() {
+                cx.create_used_variable_impl(
+                    cstr!("llvm.compiler.used"),
+                    &*cx.compiler_used_statics.borrow(),
+                );
             }
 
             // Run replace-all-uses-with for statics that need it. This must
diff --git a/compiler/rustc_codegen_llvm/src/builder.rs b/compiler/rustc_codegen_llvm/src/builder.rs
index c41a41980eb..77dd15ef4d8 100644
--- a/compiler/rustc_codegen_llvm/src/builder.rs
+++ b/compiler/rustc_codegen_llvm/src/builder.rs
@@ -1,15 +1,14 @@
+use crate::abi::FnAbiLlvmExt;
 use crate::attributes;
 use crate::common::Funclet;
 use crate::context::CodegenCx;
-use crate::llvm::{self, BasicBlock, False};
-use crate::llvm::{AtomicOrdering, AtomicRmwBinOp, SynchronizationScope};
-use crate::llvm_util;
+use crate::llvm::{self, AtomicOrdering, AtomicRmwBinOp, BasicBlock};
 use crate::type_::Type;
 use crate::type_of::LayoutLlvmExt;
 use crate::value::Value;
 use cstr::cstr;
 use libc::{c_char, c_uint};
-use rustc_codegen_ssa::common::{IntPredicate, RealPredicate, TypeKind};
+use rustc_codegen_ssa::common::{IntPredicate, RealPredicate, SynchronizationScope, TypeKind};
 use rustc_codegen_ssa::mir::operand::{OperandRef, OperandValue};
 use rustc_codegen_ssa::mir::place::PlaceRef;
 use rustc_codegen_ssa::traits::*;
@@ -28,7 +27,6 @@ use std::ffi::CStr;
 use std::iter;
 use std::ops::Deref;
 use std::ptr;
-use tracing::debug;
 
 // All Builders must have an llfn associated with them
 #[must_use]
@@ -217,6 +215,7 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
     fn invoke(
         &mut self,
         llty: &'ll Type,
+        fn_abi: Option<&FnAbi<'tcx, Ty<'tcx>>>,
         llfn: &'ll Value,
         args: &[&'ll Value],
         then: &'ll BasicBlock,
@@ -229,7 +228,7 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
         let bundle = funclet.map(|funclet| funclet.bundle());
         let bundle = bundle.as_ref().map(|b| &*b.raw);
 
-        unsafe {
+        let invoke = unsafe {
             llvm::LLVMRustBuildInvoke(
                 self.llbuilder,
                 llty,
@@ -241,7 +240,11 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
                 bundle,
                 UNNAMED,
             )
+        };
+        if let Some(fn_abi) = fn_abi {
+            fn_abi.apply_attrs_callsite(self, invoke);
         }
+        invoke
     }
 
     fn unreachable(&mut self) {
@@ -362,11 +365,14 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
                 Int(I64) => "llvm.ssub.with.overflow.i64",
                 Int(I128) => "llvm.ssub.with.overflow.i128",
 
-                Uint(U8) => "llvm.usub.with.overflow.i8",
-                Uint(U16) => "llvm.usub.with.overflow.i16",
-                Uint(U32) => "llvm.usub.with.overflow.i32",
-                Uint(U64) => "llvm.usub.with.overflow.i64",
-                Uint(U128) => "llvm.usub.with.overflow.i128",
+                Uint(_) => {
+                    // Emit sub and icmp instead of llvm.usub.with.overflow. LLVM considers these
+                    // to be the canonical form. It will attempt to reform llvm.usub.with.overflow
+                    // in the backend if profitable.
+                    let sub = self.sub(lhs, rhs);
+                    let cmp = self.icmp(IntPredicate::IntULT, lhs, rhs);
+                    return (sub, cmp);
+                }
 
                 _ => unreachable!(),
             },
@@ -408,20 +414,17 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
     fn alloca(&mut self, ty: &'ll Type, align: Align) -> &'ll Value {
         let mut bx = Builder::with_cx(self.cx);
         bx.position_at_start(unsafe { llvm::LLVMGetFirstBasicBlock(self.llfn()) });
-        bx.dynamic_alloca(ty, align)
-    }
-
-    fn dynamic_alloca(&mut self, ty: &'ll Type, align: Align) -> &'ll Value {
         unsafe {
-            let alloca = llvm::LLVMBuildAlloca(self.llbuilder, ty, UNNAMED);
+            let alloca = llvm::LLVMBuildAlloca(bx.llbuilder, ty, UNNAMED);
             llvm::LLVMSetAlignment(alloca, align.bytes() as c_uint);
             alloca
         }
     }
 
-    fn array_alloca(&mut self, ty: &'ll Type, len: &'ll Value, align: Align) -> &'ll Value {
+    fn byte_array_alloca(&mut self, len: &'ll Value, align: Align) -> &'ll Value {
         unsafe {
-            let alloca = llvm::LLVMBuildArrayAlloca(self.llbuilder, ty, len, UNNAMED);
+            let alloca =
+                llvm::LLVMBuildArrayAlloca(self.llbuilder, self.cx().type_i8(), len, UNNAMED);
             llvm::LLVMSetAlignment(alloca, align.bytes() as c_uint);
             alloca
         }
@@ -464,15 +467,15 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
         }
     }
 
+    #[instrument(level = "trace", skip(self))]
     fn load_operand(&mut self, place: PlaceRef<'tcx, &'ll Value>) -> OperandRef<'tcx, &'ll Value> {
-        debug!("PlaceRef::load: {:?}", place);
-
         assert_eq!(place.llextra.is_some(), place.layout.is_unsized());
 
         if place.layout.is_zst() {
             return OperandRef::new_zst(self, place.layout);
         }
 
+        #[instrument(level = "trace", skip(bx))]
         fn scalar_load_metadata<'a, 'll, 'tcx>(
             bx: &mut Builder<'a, 'll, 'tcx>,
             load: &'ll Value,
@@ -553,15 +556,15 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
     }
 
     fn write_operand_repeatedly(
-        mut self,
+        &mut self,
         cg_elem: OperandRef<'tcx, &'ll Value>,
         count: u64,
         dest: PlaceRef<'tcx, &'ll Value>,
-    ) -> Self {
+    ) {
         let zero = self.const_usize(0);
         let count = self.const_usize(count);
-        let start = dest.project_index(&mut self, zero).llval;
-        let end = dest.project_index(&mut self, count).llval;
+        let start = dest.project_index(self, zero).llval;
+        let end = dest.project_index(self, count).llval;
 
         let header_bb = self.append_sibling_block("repeat_loop_header");
         let body_bb = self.append_sibling_block("repeat_loop_body");
@@ -589,7 +592,7 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
         body_bx.br(header_bb);
         header_bx.add_incoming_to_phi(current, next, body_bb);
 
-        Self::build(self.cx, next_bb)
+        *self = Self::build(self.cx, next_bb);
     }
 
     fn range_metadata(&mut self, load: &'ll Value, range: WrappingRange) {
@@ -626,32 +629,6 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
         }
     }
 
-    fn type_metadata(&mut self, function: &'ll Value, typeid: String) {
-        let typeid_metadata = self.typeid_metadata(typeid);
-        let v = [self.const_usize(0), typeid_metadata];
-        unsafe {
-            llvm::LLVMGlobalSetMetadata(
-                function,
-                llvm::MD_type as c_uint,
-                llvm::LLVMValueAsMetadata(llvm::LLVMMDNodeInContext(
-                    self.cx.llcx,
-                    v.as_ptr(),
-                    v.len() as c_uint,
-                )),
-            )
-        }
-    }
-
-    fn typeid_metadata(&mut self, typeid: String) -> Self::Value {
-        unsafe {
-            llvm::LLVMMDStringInContext(
-                self.cx.llcx,
-                typeid.as_ptr() as *const c_char,
-                typeid.as_bytes().len() as c_uint,
-            )
-        }
-    }
-
     fn store(&mut self, val: &'ll Value, ptr: &'ll Value, align: Align) -> &'ll Value {
         self.store_with_flags(val, ptr, align, MemFlags::empty())
     }
@@ -752,11 +729,11 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
         unsafe { llvm::LLVMBuildSExt(self.llbuilder, val, dest_ty, UNNAMED) }
     }
 
-    fn fptoui_sat(&mut self, val: &'ll Value, dest_ty: &'ll Type) -> Option<&'ll Value> {
+    fn fptoui_sat(&mut self, val: &'ll Value, dest_ty: &'ll Type) -> &'ll Value {
         self.fptoint_sat(false, val, dest_ty)
     }
 
-    fn fptosi_sat(&mut self, val: &'ll Value, dest_ty: &'ll Type) -> Option<&'ll Value> {
+    fn fptosi_sat(&mut self, val: &'ll Value, dest_ty: &'ll Type) -> &'ll Value {
         self.fptoint_sat(true, val, dest_ty)
     }
 
@@ -1070,15 +1047,17 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
     ) -> &'ll Value {
         let weak = if weak { llvm::True } else { llvm::False };
         unsafe {
-            llvm::LLVMRustBuildAtomicCmpXchg(
+            let value = llvm::LLVMBuildAtomicCmpXchg(
                 self.llbuilder,
                 dst,
                 cmp,
                 src,
                 AtomicOrdering::from_generic(order),
                 AtomicOrdering::from_generic(failure_order),
-                weak,
-            )
+                llvm::False, // SingleThreaded
+            );
+            llvm::LLVMSetWeak(value, weak);
+            value
         }
     }
     fn atomic_rmw(
@@ -1095,7 +1074,7 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
                 dst,
                 src,
                 AtomicOrdering::from_generic(order),
-                False,
+                llvm::False, // SingleThreaded
             )
         }
     }
@@ -1103,13 +1082,18 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
     fn atomic_fence(
         &mut self,
         order: rustc_codegen_ssa::common::AtomicOrdering,
-        scope: rustc_codegen_ssa::common::SynchronizationScope,
+        scope: SynchronizationScope,
     ) {
+        let single_threaded = match scope {
+            SynchronizationScope::SingleThread => llvm::True,
+            SynchronizationScope::CrossThread => llvm::False,
+        };
         unsafe {
-            llvm::LLVMRustBuildAtomicFence(
+            llvm::LLVMBuildFence(
                 self.llbuilder,
                 AtomicOrdering::from_generic(order),
-                SynchronizationScope::from_generic(scope),
+                single_threaded,
+                UNNAMED,
             );
         }
     }
@@ -1167,6 +1151,7 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
     fn call(
         &mut self,
         llty: &'ll Type,
+        fn_abi: Option<&FnAbi<'tcx, Ty<'tcx>>>,
         llfn: &'ll Value,
         args: &[&'ll Value],
         funclet: Option<&Funclet<'ll>>,
@@ -1177,7 +1162,7 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
         let bundle = funclet.map(|funclet| funclet.bundle());
         let bundle = bundle.as_ref().map(|b| &*b.raw);
 
-        unsafe {
+        let call = unsafe {
             llvm::LLVMRustBuildCall(
                 self.llbuilder,
                 llty,
@@ -1186,7 +1171,11 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
                 args.len() as c_uint,
                 bundle,
             )
+        };
+        if let Some(fn_abi) = fn_abi {
+            fn_abi.apply_attrs_callsite(self, call);
         }
+        call
     }
 
     fn zext(&mut self, val: &'ll Value, dest_ty: &'ll Type) -> &'ll Value {
@@ -1419,7 +1408,7 @@ impl<'a, 'll, 'tcx> Builder<'a, 'll, 'tcx> {
 
     pub(crate) fn call_intrinsic(&mut self, intrinsic: &str, args: &[&'ll Value]) -> &'ll Value {
         let (ty, f) = self.cx.get_intrinsic(intrinsic);
-        self.call(ty, f, args, None)
+        self.call(ty, None, f, args, None)
     }
 
     fn call_lifetime_intrinsic(&mut self, intrinsic: &str, ptr: &'ll Value, size: Size) {
@@ -1456,51 +1445,32 @@ impl<'a, 'll, 'tcx> Builder<'a, 'll, 'tcx> {
         }
     }
 
-    fn fptoint_sat_broken_in_llvm(&self) -> bool {
-        match self.tcx.sess.target.arch.as_ref() {
-            // FIXME - https://bugs.llvm.org/show_bug.cgi?id=50083
-            "riscv64" => llvm_util::get_version() < (13, 0, 0),
-            _ => false,
-        }
-    }
-
-    fn fptoint_sat(
-        &mut self,
-        signed: bool,
-        val: &'ll Value,
-        dest_ty: &'ll Type,
-    ) -> Option<&'ll Value> {
-        if !self.fptoint_sat_broken_in_llvm() {
-            let src_ty = self.cx.val_ty(val);
-            let (float_ty, int_ty, vector_length) = if self.cx.type_kind(src_ty) == TypeKind::Vector
-            {
-                assert_eq!(self.cx.vector_length(src_ty), self.cx.vector_length(dest_ty));
-                (
-                    self.cx.element_type(src_ty),
-                    self.cx.element_type(dest_ty),
-                    Some(self.cx.vector_length(src_ty)),
-                )
-            } else {
-                (src_ty, dest_ty, None)
-            };
-            let float_width = self.cx.float_width(float_ty);
-            let int_width = self.cx.int_width(int_ty);
-
-            let instr = if signed { "fptosi" } else { "fptoui" };
-            let name = if let Some(vector_length) = vector_length {
-                format!(
-                    "llvm.{}.sat.v{}i{}.v{}f{}",
-                    instr, vector_length, int_width, vector_length, float_width
-                )
-            } else {
-                format!("llvm.{}.sat.i{}.f{}", instr, int_width, float_width)
-            };
-            let f =
-                self.declare_cfn(&name, llvm::UnnamedAddr::No, self.type_func(&[src_ty], dest_ty));
-            Some(self.call(self.type_func(&[src_ty], dest_ty), f, &[val], None))
+    fn fptoint_sat(&mut self, signed: bool, val: &'ll Value, dest_ty: &'ll Type) -> &'ll Value {
+        let src_ty = self.cx.val_ty(val);
+        let (float_ty, int_ty, vector_length) = if self.cx.type_kind(src_ty) == TypeKind::Vector {
+            assert_eq!(self.cx.vector_length(src_ty), self.cx.vector_length(dest_ty));
+            (
+                self.cx.element_type(src_ty),
+                self.cx.element_type(dest_ty),
+                Some(self.cx.vector_length(src_ty)),
+            )
         } else {
-            None
-        }
+            (src_ty, dest_ty, None)
+        };
+        let float_width = self.cx.float_width(float_ty);
+        let int_width = self.cx.int_width(int_ty);
+
+        let instr = if signed { "fptosi" } else { "fptoui" };
+        let name = if let Some(vector_length) = vector_length {
+            format!(
+                "llvm.{}.sat.v{}i{}.v{}f{}",
+                instr, vector_length, int_width, vector_length, float_width
+            )
+        } else {
+            format!("llvm.{}.sat.i{}.f{}", instr, int_width, float_width)
+        };
+        let f = self.declare_cfn(&name, llvm::UnnamedAddr::No, self.type_func(&[src_ty], dest_ty));
+        self.call(self.type_func(&[src_ty], dest_ty), None, f, &[val], None)
     }
 
     pub(crate) fn landing_pad(
diff --git a/compiler/rustc_codegen_llvm/src/callee.rs b/compiler/rustc_codegen_llvm/src/callee.rs
index ac423a22703..70ff5c9617b 100644
--- a/compiler/rustc_codegen_llvm/src/callee.rs
+++ b/compiler/rustc_codegen_llvm/src/callee.rs
@@ -6,14 +6,14 @@
 
 use crate::abi::FnAbiLlvmExt;
 use crate::attributes;
+use crate::common;
 use crate::context::CodegenCx;
 use crate::llvm;
 use crate::value::Value;
 use rustc_codegen_ssa::traits::*;
-use tracing::debug;
 
 use rustc_middle::ty::layout::{FnAbiOf, HasTyCtxt};
-use rustc_middle::ty::{self, Instance, TypeFoldable};
+use rustc_middle::ty::{self, Instance, TypeVisitable};
 
 /// Codegens a reference to a fn/method item, monomorphizing and
 /// inlining as it goes.
@@ -79,13 +79,31 @@ pub fn get_fn<'ll, 'tcx>(cx: &CodegenCx<'ll, 'tcx>, instance: Instance<'tcx>) ->
             llfn
         }
     } else {
-        let llfn = cx.declare_fn(sym, fn_abi);
+        let instance_def_id = instance.def_id();
+        let llfn = if tcx.sess.target.arch == "x86" &&
+            let Some(dllimport) = common::get_dllimport(tcx, instance_def_id, sym)
+        {
+            // Fix for https://github.com/rust-lang/rust/issues/104453
+            // On x86 Windows, LLVM uses 'L' as the prefix for any private
+            // global symbols, so when we create an undecorated function symbol
+            // that begins with an 'L' LLVM misinterprets that as a private
+            // global symbol that it created and so fails the compilation at a
+            // later stage since such a symbol must have a definition.
+            //
+            // To avoid this, we set the Storage Class to "DllImport" so that
+            // LLVM will prefix the name with `__imp_`. Ideally, we'd like the
+            // existing logic below to set the Storage Class, but it has an
+            // exemption for MinGW for backwards compatability.
+            let llfn = cx.declare_fn(&common::i686_decorated_name(&dllimport, common::is_mingw_gnu_toolchain(&tcx.sess.target), true), fn_abi);
+            unsafe { llvm::LLVMSetDLLStorageClass(llfn, llvm::DLLStorageClass::DllImport); }
+            llfn
+        } else {
+            cx.declare_fn(sym, fn_abi)
+        };
         debug!("get_fn: not casting pointer!");
 
         attributes::from_fn_attrs(cx, llfn, instance);
 
-        let instance_def_id = instance.def_id();
-
         // Apply an appropriate linkage/visibility value to our item that we
         // just declared.
         //
@@ -174,7 +192,8 @@ pub fn get_fn<'ll, 'tcx>(cx: &CodegenCx<'ll, 'tcx>, instance: Instance<'tcx>) ->
             // MinGW: For backward compatibility we rely on the linker to decide whether it
             // should use dllimport for functions.
             if cx.use_dll_storage_attrs
-                && tcx.is_dllimport_foreign_item(instance_def_id)
+                && let Some(library) = tcx.native_library(instance_def_id)
+                && library.kind.is_dllimport()
                 && !matches!(tcx.sess.target.env.as_ref(), "gnu" | "uclibc")
             {
                 llvm::LLVMSetDLLStorageClass(llfn, llvm::DLLStorageClass::DllImport);
diff --git a/compiler/rustc_codegen_llvm/src/common.rs b/compiler/rustc_codegen_llvm/src/common.rs
index b69d7a000ee..acee9134fb9 100644
--- a/compiler/rustc_codegen_llvm/src/common.rs
+++ b/compiler/rustc_codegen_llvm/src/common.rs
@@ -10,15 +10,17 @@ use crate::value::Value;
 use rustc_ast::Mutability;
 use rustc_codegen_ssa::mir::place::PlaceRef;
 use rustc_codegen_ssa::traits::*;
+use rustc_hir::def_id::DefId;
 use rustc_middle::bug;
 use rustc_middle::mir::interpret::{ConstAllocation, GlobalAlloc, Scalar};
 use rustc_middle::ty::layout::{LayoutOf, TyAndLayout};
-use rustc_middle::ty::ScalarInt;
-use rustc_span::symbol::Symbol;
+use rustc_middle::ty::TyCtxt;
+use rustc_session::cstore::{DllCallingConvention, DllImport, PeImportNameType};
 use rustc_target::abi::{self, AddressSpace, HasDataLayout, Pointer, Size};
+use rustc_target::spec::Target;
 
 use libc::{c_char, c_uint};
-use tracing::debug;
+use std::fmt::Write;
 
 /*
 * A note on nomenclature of linking: "extern", "foreign", and "upcall".
@@ -109,8 +111,7 @@ impl<'ll> CodegenCx<'ll, '_> {
     pub fn const_get_elt(&self, v: &'ll Value, idx: u64) -> &'ll Value {
         unsafe {
             assert_eq!(idx as c_uint as u64, idx);
-            let us = &[idx as c_uint];
-            let r = llvm::LLVMConstExtractValue(v, us.as_ptr(), us.len() as c_uint);
+            let r = llvm::LLVMGetAggregateElement(v, idx as c_uint).unwrap();
 
             debug!("const_get_elt(v={:?}, idx={}, r={:?})", v, idx, r);
 
@@ -181,22 +182,27 @@ impl<'ll, 'tcx> ConstMethods<'tcx> for CodegenCx<'ll, 'tcx> {
         unsafe { llvm::LLVMConstReal(t, val) }
     }
 
-    fn const_str(&self, s: Symbol) -> (&'ll Value, &'ll Value) {
-        let s_str = s.as_str();
-        let str_global = *self.const_str_cache.borrow_mut().entry(s).or_insert_with(|| {
-            let sc = self.const_bytes(s_str.as_bytes());
-            let sym = self.generate_local_symbol_name("str");
-            let g = self.define_global(&sym, self.val_ty(sc)).unwrap_or_else(|| {
-                bug!("symbol `{}` is already defined", sym);
-            });
-            unsafe {
-                llvm::LLVMSetInitializer(g, sc);
-                llvm::LLVMSetGlobalConstant(g, True);
-                llvm::LLVMRustSetLinkage(g, llvm::Linkage::InternalLinkage);
-            }
-            g
-        });
-        let len = s_str.len();
+    fn const_str(&self, s: &str) -> (&'ll Value, &'ll Value) {
+        let str_global = *self
+            .const_str_cache
+            .borrow_mut()
+            .raw_entry_mut()
+            .from_key(s)
+            .or_insert_with(|| {
+                let sc = self.const_bytes(s.as_bytes());
+                let sym = self.generate_local_symbol_name("str");
+                let g = self.define_global(&sym, self.val_ty(sc)).unwrap_or_else(|| {
+                    bug!("symbol `{}` is already defined", sym);
+                });
+                unsafe {
+                    llvm::LLVMSetInitializer(g, sc);
+                    llvm::LLVMSetGlobalConstant(g, True);
+                    llvm::LLVMRustSetLinkage(g, llvm::Linkage::InternalLinkage);
+                }
+                (s.to_owned(), g)
+            })
+            .1;
+        let len = s.len();
         let cs = consts::ptrcast(
             str_global,
             self.type_ptr_to(self.layout_of(self.tcx.types.str_).llvm_type(self)),
@@ -209,7 +215,11 @@ impl<'ll, 'tcx> ConstMethods<'tcx> for CodegenCx<'ll, 'tcx> {
     }
 
     fn const_to_opt_uint(&self, v: &'ll Value) -> Option<u64> {
-        try_as_const_integral(v).map(|v| unsafe { llvm::LLVMConstIntGetZExtValue(v) })
+        try_as_const_integral(v).and_then(|v| unsafe {
+            let mut i = 0u64;
+            let success = llvm::LLVMRustConstIntGetZExtValue(v, &mut i);
+            success.then_some(i)
+        })
     }
 
     fn const_to_opt_u128(&self, v: &'ll Value, sign_ext: bool) -> Option<u128> {
@@ -223,10 +233,6 @@ impl<'ll, 'tcx> ConstMethods<'tcx> for CodegenCx<'ll, 'tcx> {
     fn scalar_to_backend(&self, cv: Scalar, layout: abi::Scalar, llty: &'ll Type) -> &'ll Value {
         let bitsize = if layout.is_bool() { 1 } else { layout.size(self).bits() };
         match cv {
-            Scalar::Int(ScalarInt::ZST) => {
-                assert_eq!(0, layout.size(self).bytes());
-                self.const_undef(self.type_ix(0))
-            }
             Scalar::Int(int) => {
                 let data = int.assert_bits(layout.size(self));
                 let llval = self.const_uint_big(self.type_ix(bitsize), data);
@@ -255,6 +261,15 @@ impl<'ll, 'tcx> ConstMethods<'tcx> for CodegenCx<'ll, 'tcx> {
                         self.get_fn_addr(fn_instance.polymorphize(self.tcx)),
                         self.data_layout().instruction_address_space,
                     ),
+                    GlobalAlloc::VTable(ty, trait_ref) => {
+                        let alloc = self
+                            .tcx
+                            .global_alloc(self.tcx.vtable_allocation((ty, trait_ref)))
+                            .unwrap_memory();
+                        let init = const_alloc_to_llvm(self, alloc);
+                        let value = self.static_addr_of(init, alloc.inner().align, None);
+                        (value, AddressSpace::DATA)
+                    }
                     GlobalAlloc::Static(def_id) => {
                         assert!(self.tcx.is_static(def_id));
                         assert!(!self.tcx.is_thread_local_static(def_id));
@@ -346,3 +361,74 @@ fn hi_lo_to_u128(lo: u64, hi: u64) -> u128 {
 fn try_as_const_integral(v: &Value) -> Option<&ConstantInt> {
     unsafe { llvm::LLVMIsAConstantInt(v) }
 }
+
+pub(crate) fn get_dllimport<'tcx>(
+    tcx: TyCtxt<'tcx>,
+    id: DefId,
+    name: &str,
+) -> Option<&'tcx DllImport> {
+    tcx.native_library(id)
+        .map(|lib| lib.dll_imports.iter().find(|di| di.name.as_str() == name))
+        .flatten()
+}
+
+pub(crate) fn is_mingw_gnu_toolchain(target: &Target) -> bool {
+    target.vendor == "pc" && target.os == "windows" && target.env == "gnu" && target.abi.is_empty()
+}
+
+pub(crate) fn i686_decorated_name(
+    dll_import: &DllImport,
+    mingw: bool,
+    disable_name_mangling: bool,
+) -> String {
+    let name = dll_import.name.as_str();
+
+    let (add_prefix, add_suffix) = match dll_import.import_name_type {
+        Some(PeImportNameType::NoPrefix) => (false, true),
+        Some(PeImportNameType::Undecorated) => (false, false),
+        _ => (true, true),
+    };
+
+    // Worst case: +1 for disable name mangling, +1 for prefix, +4 for suffix (@@__).
+    let mut decorated_name = String::with_capacity(name.len() + 6);
+
+    if disable_name_mangling {
+        // LLVM uses a binary 1 ('\x01') prefix to a name to indicate that mangling needs to be disabled.
+        decorated_name.push('\x01');
+    }
+
+    let prefix = if add_prefix && dll_import.is_fn {
+        match dll_import.calling_convention {
+            DllCallingConvention::C | DllCallingConvention::Vectorcall(_) => None,
+            DllCallingConvention::Stdcall(_) => (!mingw
+                || dll_import.import_name_type == Some(PeImportNameType::Decorated))
+            .then_some('_'),
+            DllCallingConvention::Fastcall(_) => Some('@'),
+        }
+    } else if !dll_import.is_fn && !mingw {
+        // For static variables, prefix with '_' on MSVC.
+        Some('_')
+    } else {
+        None
+    };
+    if let Some(prefix) = prefix {
+        decorated_name.push(prefix);
+    }
+
+    decorated_name.push_str(name);
+
+    if add_suffix && dll_import.is_fn {
+        match dll_import.calling_convention {
+            DllCallingConvention::C => {}
+            DllCallingConvention::Stdcall(arg_list_size)
+            | DllCallingConvention::Fastcall(arg_list_size) => {
+                write!(&mut decorated_name, "@{}", arg_list_size).unwrap();
+            }
+            DllCallingConvention::Vectorcall(arg_list_size) => {
+                write!(&mut decorated_name, "@@{}", arg_list_size).unwrap();
+            }
+        }
+    }
+
+    decorated_name
+}
diff --git a/compiler/rustc_codegen_llvm/src/consts.rs b/compiler/rustc_codegen_llvm/src/consts.rs
index 5bbbfe9a4ab..3626aa901c0 100644
--- a/compiler/rustc_codegen_llvm/src/consts.rs
+++ b/compiler/rustc_codegen_llvm/src/consts.rs
@@ -1,6 +1,7 @@
 use crate::base;
-use crate::common::CodegenCx;
+use crate::common::{self, CodegenCx};
 use crate::debuginfo;
+use crate::errors::{InvalidMinimumAlignment, SymbolAlreadyDefined};
 use crate::llvm::{self, True};
 use crate::llvm_util;
 use crate::type_::Type;
@@ -19,29 +20,27 @@ use rustc_middle::mir::mono::MonoItem;
 use rustc_middle::ty::layout::LayoutOf;
 use rustc_middle::ty::{self, Instance, Ty};
 use rustc_middle::{bug, span_bug};
+use rustc_session::config::Lto;
 use rustc_target::abi::{
     AddressSpace, Align, HasDataLayout, Primitive, Scalar, Size, WrappingRange,
 };
 use std::ops::Range;
-use tracing::debug;
 
 pub fn const_alloc_to_llvm<'ll>(cx: &CodegenCx<'ll, '_>, alloc: ConstAllocation<'_>) -> &'ll Value {
     let alloc = alloc.inner();
-    let mut llvals = Vec::with_capacity(alloc.relocations().len() + 1);
+    let mut llvals = Vec::with_capacity(alloc.provenance().ptrs().len() + 1);
     let dl = cx.data_layout();
     let pointer_size = dl.pointer_size.bytes() as usize;
 
-    // Note: this function may call `inspect_with_uninit_and_ptr_outside_interpreter`,
-    // so `range` must be within the bounds of `alloc` and not contain or overlap a relocation.
+    // Note: this function may call `inspect_with_uninit_and_ptr_outside_interpreter`, so `range`
+    // must be within the bounds of `alloc` and not contain or overlap a pointer provenance.
     fn append_chunks_of_init_and_uninit_bytes<'ll, 'a, 'b>(
         llvals: &mut Vec<&'ll Value>,
         cx: &'a CodegenCx<'ll, 'b>,
         alloc: &'a Allocation,
         range: Range<usize>,
     ) {
-        let chunks = alloc
-            .init_mask()
-            .range_as_init_chunks(Size::from_bytes(range.start), Size::from_bytes(range.end));
+        let chunks = alloc.init_mask().range_as_init_chunks(range.clone().into());
 
         let chunk_to_llval = move |chunk| match chunk {
             InitChunk::Init(range) => {
@@ -64,7 +63,7 @@ pub fn const_alloc_to_llvm<'ll>(cx: &CodegenCx<'ll, '_>, alloc: ConstAllocation<
             // See https://github.com/rust-lang/rust/issues/84565.
             1
         } else {
-            cx.sess().opts.debugging_opts.uninit_const_chunk_threshold
+            cx.sess().opts.unstable_opts.uninit_const_chunk_threshold
         };
         let allow_uninit_chunks = chunks.clone().take(max.saturating_add(1)).count() <= max;
 
@@ -79,12 +78,12 @@ pub fn const_alloc_to_llvm<'ll>(cx: &CodegenCx<'ll, '_>, alloc: ConstAllocation<
     }
 
     let mut next_offset = 0;
-    for &(offset, alloc_id) in alloc.relocations().iter() {
+    for &(offset, alloc_id) in alloc.provenance().ptrs().iter() {
         let offset = offset.bytes();
         assert_eq!(offset as usize as u64, offset);
         let offset = offset as usize;
         if offset > next_offset {
-            // This `inspect` is okay since we have checked that it is not within a relocation, it
+            // This `inspect` is okay since we have checked that there is no provenance, it
             // is within the bounds of the allocation, and it doesn't affect interpreter execution
             // (we inspect the result after interpreter execution).
             append_chunks_of_init_and_uninit_bytes(&mut llvals, cx, alloc, next_offset..offset);
@@ -93,7 +92,7 @@ pub fn const_alloc_to_llvm<'ll>(cx: &CodegenCx<'ll, '_>, alloc: ConstAllocation<
             dl.endian,
             // This `inspect` is okay since it is within the bounds of the allocation, it doesn't
             // affect interpreter execution (we inspect the result after interpreter execution),
-            // and we properly interpret the relocation as a relocation pointer offset.
+            // and we properly interpret the provenance as a relocation pointer offset.
             alloc.inspect_with_uninit_and_ptr_outside_interpreter(offset..(offset + pointer_size)),
         )
         .expect("const_alloc_to_llvm: could not read relocation pointer")
@@ -101,7 +100,9 @@ pub fn const_alloc_to_llvm<'ll>(cx: &CodegenCx<'ll, '_>, alloc: ConstAllocation<
 
         let address_space = match cx.tcx.global_alloc(alloc_id) {
             GlobalAlloc::Function(..) => cx.data_layout().instruction_address_space,
-            GlobalAlloc::Static(..) | GlobalAlloc::Memory(..) => AddressSpace::DATA,
+            GlobalAlloc::Static(..) | GlobalAlloc::Memory(..) | GlobalAlloc::VTable(..) => {
+                AddressSpace::DATA
+            }
         };
 
         llvals.push(cx.scalar_to_backend(
@@ -119,7 +120,7 @@ pub fn const_alloc_to_llvm<'ll>(cx: &CodegenCx<'ll, '_>, alloc: ConstAllocation<
     }
     if alloc.len() >= next_offset {
         let range = next_offset..alloc.len();
-        // This `inspect` is okay since we have check that it is after all relocations, it is
+        // This `inspect` is okay since we have check that it is after all provenance, it is
         // within the bounds of the allocation, and it doesn't affect interpreter execution (we
         // inspect the result after interpreter execution).
         append_chunks_of_init_and_uninit_bytes(&mut llvals, cx, alloc, range);
@@ -144,7 +145,7 @@ fn set_global_alignment<'ll>(cx: &CodegenCx<'ll, '_>, gv: &'ll Value, mut align:
         match Align::from_bits(min) {
             Ok(min) => align = align.max(min),
             Err(err) => {
-                cx.sess().err(&format!("invalid minimum global alignment: {}", err));
+                cx.sess().emit_err(InvalidMinimumAlignment { err });
             }
         }
     }
@@ -158,28 +159,15 @@ fn check_and_apply_linkage<'ll, 'tcx>(
     attrs: &CodegenFnAttrs,
     ty: Ty<'tcx>,
     sym: &str,
-    span_def_id: DefId,
+    def_id: DefId,
 ) -> &'ll Value {
     let llty = cx.layout_of(ty).llvm_type(cx);
-    if let Some(linkage) = attrs.linkage {
+    if let Some(linkage) = attrs.import_linkage {
         debug!("get_static: sym={} linkage={:?}", sym, linkage);
 
-        // If this is a static with a linkage specified, then we need to handle
-        // it a little specially. The typesystem prevents things like &T and
-        // extern "C" fn() from being non-null, so we can't just declare a
-        // static and call it a day. Some linkages (like weak) will make it such
-        // that the static actually has a null value.
-        let llty2 = if let ty::RawPtr(ref mt) = ty.kind() {
-            cx.layout_of(mt.ty).llvm_type(cx)
-        } else {
-            cx.sess().span_fatal(
-                cx.tcx.def_span(span_def_id),
-                "must have type `*const T` or `*mut T` due to `#[linkage]` attribute",
-            )
-        };
         unsafe {
             // Declare a symbol `foo` with the desired linkage.
-            let g1 = cx.declare_global(sym, llty2);
+            let g1 = cx.declare_global(sym, cx.type_i8());
             llvm::LLVMRustSetLinkage(g1, base::linkage_to_llvm(linkage));
 
             // Declare an internal global `extern_with_linkage_foo` which
@@ -191,15 +179,19 @@ fn check_and_apply_linkage<'ll, 'tcx>(
             let mut real_name = "_rust_extern_with_linkage_".to_string();
             real_name.push_str(sym);
             let g2 = cx.define_global(&real_name, llty).unwrap_or_else(|| {
-                cx.sess().span_fatal(
-                    cx.tcx.def_span(span_def_id),
-                    &format!("symbol `{}` is already defined", &sym),
-                )
+                cx.sess().emit_fatal(SymbolAlreadyDefined {
+                    span: cx.tcx.def_span(def_id),
+                    symbol_name: sym,
+                })
             });
             llvm::LLVMRustSetLinkage(g2, llvm::Linkage::InternalLinkage);
-            llvm::LLVMSetInitializer(g2, g1);
+            llvm::LLVMSetInitializer(g2, cx.const_ptrcast(g1, llty));
             g2
         }
+    } else if cx.tcx.sess.target.arch == "x86" &&
+        let Some(dllimport) = common::get_dllimport(cx.tcx, def_id, sym)
+    {
+        cx.declare_global(&common::i686_decorated_name(&dllimport, common::is_mingw_gnu_toolchain(&cx.tcx.sess.target), true), llty)
     } else {
         // Generate an external declaration.
         // FIXME(nagisa): investigate whether it can be changed into define_global
@@ -293,12 +285,23 @@ impl<'ll> CodegenCx<'ll, '_> {
             llvm::set_thread_local_mode(g, self.tls_model);
         }
 
+        let dso_local = unsafe { self.should_assume_dso_local(g, true) };
+        if dso_local {
+            unsafe {
+                llvm::LLVMRustSetDSOLocal(g, true);
+            }
+        }
+
         if !def_id.is_local() {
             let needs_dll_storage_attr = self.use_dll_storage_attrs && !self.tcx.is_foreign_item(def_id) &&
+                // Local definitions can never be imported, so we must not apply
+                // the DLLImport annotation.
+                !dso_local &&
                 // ThinLTO can't handle this workaround in all cases, so we don't
                 // emit the attrs. Instead we make them unnecessary by disallowing
                 // dynamic linking when linker plugin based LTO is enabled.
-                !self.tcx.sess.opts.cg.linker_plugin_lto.enabled();
+                !self.tcx.sess.opts.cg.linker_plugin_lto.enabled() &&
+                self.tcx.sess.lto() != Lto::Thin;
 
             // If this assertion triggers, there's something wrong with commandline
             // argument validation.
@@ -327,19 +330,16 @@ impl<'ll> CodegenCx<'ll, '_> {
             }
         }
 
-        if self.use_dll_storage_attrs && self.tcx.is_dllimport_foreign_item(def_id) {
+        if self.use_dll_storage_attrs
+            && let Some(library) = self.tcx.native_library(def_id)
+            && library.kind.is_dllimport()
+        {
             // For foreign (native) libs we know the exact storage type to use.
             unsafe {
                 llvm::LLVMSetDLLStorageClass(g, llvm::DLLStorageClass::DllImport);
             }
         }
 
-        unsafe {
-            if self.should_assume_dso_local(g, true) {
-                llvm::LLVMRustSetDSOLocal(g, true);
-            }
-        }
-
         self.instances.borrow_mut().insert(instance, g);
         g
     }
@@ -473,7 +473,7 @@ impl<'ll> StaticMethods for CodegenCx<'ll, '_> {
                 //
                 // We could remove this hack whenever we decide to drop macOS 10.10 support.
                 if self.tcx.sess.target.is_like_osx {
-                    // The `inspect` method is okay here because we checked relocations, and
+                    // The `inspect` method is okay here because we checked for provenance, and
                     // because we are doing this access to inspect the final interpreter state
                     // (not as part of the interpreter execution).
                     //
@@ -481,7 +481,7 @@ impl<'ll> StaticMethods for CodegenCx<'ll, '_> {
                     // happens to be zero. Instead, we should only check the value of defined bytes
                     // and set all undefined bytes to zero if this allocation is headed for the
                     // BSS.
-                    let all_bytes_are_zero = alloc.relocations().is_empty()
+                    let all_bytes_are_zero = alloc.provenance().ptrs().is_empty()
                         && alloc
                             .inspect_with_uninit_and_ptr_outside_interpreter(0..alloc.len())
                             .iter()
@@ -505,9 +505,9 @@ impl<'ll> StaticMethods for CodegenCx<'ll, '_> {
                         section.as_str().as_ptr().cast(),
                         section.as_str().len() as c_uint,
                     );
-                    assert!(alloc.relocations().is_empty());
+                    assert!(alloc.provenance().ptrs().is_empty());
 
-                    // The `inspect` method is okay here because we checked relocations, and
+                    // The `inspect` method is okay here because we checked for provenance, and
                     // because we are doing this access to inspect the final interpreter state (not
                     // as part of the interpreter execution).
                     let bytes =
@@ -535,10 +535,20 @@ impl<'ll> StaticMethods for CodegenCx<'ll, '_> {
 
                 // The semantics of #[used] in Rust only require the symbol to make it into the
                 // object file. It is explicitly allowed for the linker to strip the symbol if it
-                // is dead. As such, use llvm.compiler.used instead of llvm.used.
+                // is dead, which means we are allowed use `llvm.compiler.used` instead of
+                // `llvm.used` here.
+                //
                 // Additionally, https://reviews.llvm.org/D97448 in LLVM 13 started emitting unique
                 // sections with SHF_GNU_RETAIN flag for llvm.used symbols, which may trigger bugs
-                // in some versions of the gold linker.
+                // in the handling of `.init_array` (the static constructor list) in versions of
+                // the gold linker (prior to the one released with binutils 2.36).
+                //
+                // That said, we only ever emit these when compiling for ELF targets, unless
+                // `#[used(compiler)]` is explicitly requested. This is to avoid similar breakage
+                // on other targets, in particular MachO targets have *their* static constructor
+                // lists broken if `llvm.compiler.used` is emitted rather than llvm.used. However,
+                // that check happens when assigning the `CodegenFnAttrFlags` in `rustc_hir_analysis`,
+                // so we don't need to take care of it here.
                 self.add_compiler_used_global(g);
             }
             if attrs.flags.contains(CodegenFnAttrFlags::USED_LINKER) {
diff --git a/compiler/rustc_codegen_llvm/src/context.rs b/compiler/rustc_codegen_llvm/src/context.rs
index b5c31fcebe0..4dcc7cd5447 100644
--- a/compiler/rustc_codegen_llvm/src/context.rs
+++ b/compiler/rustc_codegen_llvm/src/context.rs
@@ -3,6 +3,7 @@ use crate::back::write::to_llvm_code_model;
 use crate::callee::get_fn;
 use crate::coverageinfo;
 use crate::debuginfo;
+use crate::errors::BranchProtectionRequiresAArch64;
 use crate::llvm;
 use crate::llvm_util;
 use crate::type_::Type;
@@ -26,7 +27,7 @@ use rustc_session::config::{BranchProtection, CFGuard, CFProtection};
 use rustc_session::config::{CrateType, DebugInfo, PAuthKey, PacRet};
 use rustc_session::Session;
 use rustc_span::source_map::Span;
-use rustc_span::symbol::Symbol;
+use rustc_span::source_map::Spanned;
 use rustc_target::abi::{
     call::FnAbi, HasDataLayout, PointeeInfo, Size, TargetDataLayout, VariantIdx,
 };
@@ -56,7 +57,7 @@ pub struct CodegenCx<'ll, 'tcx> {
     pub vtables:
         RefCell<FxHashMap<(Ty<'tcx>, Option<ty::PolyExistentialTraitRef<'tcx>>), &'ll Value>>,
     /// Cache of constant strings,
-    pub const_str_cache: RefCell<FxHashMap<Symbol, &'ll Value>>,
+    pub const_str_cache: RefCell<FxHashMap<String, &'ll Value>>,
 
     /// Reverse-direction for const ptrs cast from globals.
     ///
@@ -143,17 +144,6 @@ pub unsafe fn create_module<'ll>(
 
     let mut target_data_layout = sess.target.data_layout.to_string();
     let llvm_version = llvm_util::get_version();
-    if llvm_version < (13, 0, 0) {
-        if sess.target.arch == "powerpc64" {
-            target_data_layout = target_data_layout.replace("-S128", "");
-        }
-        if sess.target.arch == "wasm32" {
-            target_data_layout = "e-m:e-p:32:32-i64:64-n32:64-S128".to_string();
-        }
-        if sess.target.arch == "wasm64" {
-            target_data_layout = "e-m:e-p:64:64-i64:64-n32:64-S128".to_string();
-        }
-    }
     if llvm_version < (14, 0, 0) {
         if sess.target.llvm_target == "i686-pc-windows-msvc"
             || sess.target.llvm_target == "i586-pc-windows-msvc"
@@ -166,6 +156,15 @@ pub unsafe fn create_module<'ll>(
             target_data_layout = target_data_layout.replace("-p10:8:8-p20:8:8", "");
         }
     }
+    if llvm_version < (16, 0, 0) {
+        if sess.target.arch == "s390x" {
+            target_data_layout = target_data_layout.replace("-v128:64", "");
+        }
+
+        if sess.target.arch == "riscv64" {
+            target_data_layout = target_data_layout.replace("-n32:64-", "-n64-");
+        }
+    }
 
     // Ensure the data-layout values hardcoded remain the defaults.
     if sess.target.is_builtin {
@@ -276,9 +275,9 @@ pub unsafe fn create_module<'ll>(
         }
     }
 
-    if let Some(BranchProtection { bti, pac_ret }) = sess.opts.debugging_opts.branch_protection {
+    if let Some(BranchProtection { bti, pac_ret }) = sess.opts.unstable_opts.branch_protection {
         if sess.target.arch != "aarch64" {
-            sess.err("-Zbranch-protection is only supported on aarch64");
+            sess.emit_err(BranchProtectionRequiresAArch64);
         } else {
             llvm::LLVMRustAddModuleFlag(
                 llmod,
@@ -309,7 +308,7 @@ pub unsafe fn create_module<'ll>(
     }
 
     // Pass on the control-flow protection flags to LLVM (equivalent to `-fcf-protection` in Clang).
-    if let CFProtection::Branch | CFProtection::Full = sess.opts.debugging_opts.cf_protection {
+    if let CFProtection::Branch | CFProtection::Full = sess.opts.unstable_opts.cf_protection {
         llvm::LLVMRustAddModuleFlag(
             llmod,
             llvm::LLVMModFlagBehavior::Override,
@@ -317,7 +316,7 @@ pub unsafe fn create_module<'ll>(
             1,
         )
     }
-    if let CFProtection::Return | CFProtection::Full = sess.opts.debugging_opts.cf_protection {
+    if let CFProtection::Return | CFProtection::Full = sess.opts.unstable_opts.cf_protection {
         llvm::LLVMRustAddModuleFlag(
             llmod,
             llvm::LLVMModFlagBehavior::Override,
@@ -326,7 +325,7 @@ pub unsafe fn create_module<'ll>(
         )
     }
 
-    if sess.opts.debugging_opts.virtual_function_elimination {
+    if sess.opts.unstable_opts.virtual_function_elimination {
         llvm::LLVMRustAddModuleFlag(
             llmod,
             llvm::LLVMModFlagBehavior::Error,
@@ -465,7 +464,7 @@ impl<'ll, 'tcx> CodegenCx<'ll, 'tcx> {
         self.coverage_cx.as_ref()
     }
 
-    fn create_used_variable_impl(&self, name: &'static CStr, values: &[&'ll Value]) {
+    pub(crate) fn create_used_variable_impl(&self, name: &'static CStr, values: &[&'ll Value]) {
         let section = cstr!("llvm.metadata");
         let array = self.const_array(self.type_ptr_to(self.type_i8()), values);
 
@@ -563,14 +562,6 @@ impl<'ll, 'tcx> MiscMethods<'tcx> for CodegenCx<'ll, 'tcx> {
         self.codegen_unit
     }
 
-    fn used_statics(&self) -> &RefCell<Vec<&'ll Value>> {
-        &self.used_statics
-    }
-
-    fn compiler_used_statics(&self) -> &RefCell<Vec<&'ll Value>> {
-        &self.compiler_used_statics
-    }
-
     fn set_frame_pointer_type(&self, llfn: &'ll Value) {
         if let Some(attr) = attributes::frame_pointer_type_attr(self) {
             attributes::apply_to_llfn(llfn, llvm::AttributePlace::Function, &[attr]);
@@ -584,20 +575,15 @@ impl<'ll, 'tcx> MiscMethods<'tcx> for CodegenCx<'ll, 'tcx> {
         attributes::apply_to_llfn(llfn, llvm::AttributePlace::Function, &attrs);
     }
 
-    fn create_used_variable(&self) {
-        self.create_used_variable_impl(cstr!("llvm.used"), &*self.used_statics.borrow());
-    }
-
-    fn create_compiler_used_variable(&self) {
-        self.create_used_variable_impl(
-            cstr!("llvm.compiler.used"),
-            &*self.compiler_used_statics.borrow(),
-        );
-    }
-
     fn declare_c_main(&self, fn_type: Self::Type) -> Option<Self::Function> {
-        if self.get_declared_value("main").is_none() {
-            Some(self.declare_cfn("main", llvm::UnnamedAddr::Global, fn_type))
+        let entry_name = self.sess().target.entry_name.as_ref();
+        if self.get_declared_value(entry_name).is_none() {
+            Some(self.declare_entry_fn(
+                entry_name,
+                self.sess().target.entry_abi.into(),
+                llvm::UnnamedAddr::Global,
+                fn_type,
+            ))
         } else {
             // If the symbol already exists, it is an error: for example, the user wrote
             // #[no_mangle] extern "C" fn main(..) {..}
@@ -898,6 +884,9 @@ impl<'ll> CodegenCx<'ll, '_> {
             ifn!("llvm.dbg.declare", fn(t_metadata, t_metadata) -> void);
             ifn!("llvm.dbg.value", fn(t_metadata, t_i64, t_metadata) -> void);
         }
+
+        ifn!("llvm.ptrmask", fn(i8p, t_isize) -> i8p);
+
         None
     }
 
@@ -906,7 +895,7 @@ impl<'ll> CodegenCx<'ll, '_> {
             return eh_catch_typeinfo;
         }
         let tcx = self.tcx;
-        assert!(self.sess().target.is_like_emscripten);
+        assert!(self.sess().target.os == "emscripten");
         let eh_catch_typeinfo = match tcx.lang_items().eh_catch_typeinfo() {
             Some(def_id) => self.get_static(def_id),
             _ => {
@@ -970,7 +959,7 @@ impl<'tcx> LayoutOfHelpers<'tcx> for CodegenCx<'_, 'tcx> {
     #[inline]
     fn handle_layout_err(&self, err: LayoutError<'tcx>, span: Span, ty: Ty<'tcx>) -> ! {
         if let LayoutError::SizeOverflow(_) = err {
-            self.sess().span_fatal(span, &err.to_string())
+            self.sess().emit_fatal(Spanned { span, node: err })
         } else {
             span_bug!(span, "failed to get layout for `{}`: {}", ty, err)
         }
@@ -988,7 +977,7 @@ impl<'tcx> FnAbiOfHelpers<'tcx> for CodegenCx<'_, 'tcx> {
         fn_abi_request: FnAbiRequest<'tcx>,
     ) -> ! {
         if let FnAbiError::Layout(LayoutError::SizeOverflow(_)) = err {
-            self.sess().span_fatal(span, &err.to_string())
+            self.sess().emit_fatal(Spanned { span, node: err })
         } else {
             match fn_abi_request {
                 FnAbiRequest::OfFnPtr { sig, extra_args } => {
diff --git a/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs b/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs
index 58f391692c4..86580d05d41 100644
--- a/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs
+++ b/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs
@@ -1,5 +1,6 @@
 use crate::common::CodegenCx;
 use crate::coverageinfo;
+use crate::errors::InstrumentCoverageRequiresLLVM12;
 use crate::llvm;
 
 use llvm::coverageinfo::CounterMappingRegion;
@@ -16,8 +17,6 @@ use rustc_middle::ty::TyCtxt;
 
 use std::ffi::CString;
 
-use tracing::debug;
-
 /// Generates and exports the Coverage Map.
 ///
 /// Rust Coverage Map generation supports LLVM Coverage Mapping Format versions
@@ -39,7 +38,7 @@ pub fn finalize<'ll, 'tcx>(cx: &CodegenCx<'ll, 'tcx>) {
     // LLVM 12.
     let version = coverageinfo::mapping_version();
     if version < 4 {
-        tcx.sess.fatal("rustc option `-C instrument-coverage` requires LLVM 12 or higher.");
+        tcx.sess.emit_fatal(InstrumentCoverageRequiresLLVM12);
     }
 
     debug!("Generating coverage map for CodegenUnit: `{}`", cx.codegen_unit.name());
@@ -131,7 +130,7 @@ impl CoverageMapGenerator {
             // LLVM Coverage Mapping Format version 6 (zero-based encoded as 5)
             // requires setting the first filename to the compilation directory.
             // Since rustc generates coverage maps with relative paths, the
-            // compilation directory can be combined with the the relative paths
+            // compilation directory can be combined with the relative paths
             // to get absolute paths, if needed.
             let working_dir = tcx
                 .sess
@@ -175,7 +174,7 @@ impl CoverageMapGenerator {
         counter_regions.sort_unstable_by_key(|(_counter, region)| *region);
         for (counter, region) in counter_regions {
             let CodeRegion { file_name, start_line, start_col, end_line, end_col } = *region;
-            let same_file = current_file_name.as_ref().map_or(false, |p| *p == file_name);
+            let same_file = current_file_name.map_or(false, |p| p == file_name);
             if !same_file {
                 if current_file_name.is_some() {
                     current_file_id += 1;
diff --git a/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs b/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs
index 98ba38356a4..ace15cfb024 100644
--- a/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs
+++ b/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs
@@ -28,7 +28,6 @@ use std::cell::RefCell;
 use std::ffi::CString;
 
 use std::iter;
-use tracing::debug;
 
 pub mod mapgen;
 
@@ -38,7 +37,7 @@ const VAR_ALIGN_BYTES: usize = 8;
 
 /// A context object for maintaining all state needed by the coverageinfo module.
 pub struct CrateCoverageContext<'ll, 'tcx> {
-    // Coverage data for each instrumented function identified by DefId.
+    /// Coverage data for each instrumented function identified by DefId.
     pub(crate) function_coverage_map: RefCell<FxHashMap<Instance<'tcx>, FunctionCoverage<'tcx>>>,
     pub(crate) pgo_func_name_var_map: RefCell<FxHashMap<Instance<'tcx>, &'ll llvm::Value>>,
 }
diff --git a/compiler/rustc_codegen_llvm/src/debuginfo/gdb.rs b/compiler/rustc_codegen_llvm/src/debuginfo/gdb.rs
index 5186aee57fb..80fd9726fc7 100644
--- a/compiler/rustc_codegen_llvm/src/debuginfo/gdb.rs
+++ b/compiler/rustc_codegen_llvm/src/debuginfo/gdb.rs
@@ -55,7 +55,7 @@ pub fn get_or_insert_gdb_debug_scripts_section_global<'ll>(cx: &CodegenCx<'ll, '
             // The initial byte `4` instructs GDB that the following pretty printer
             // is defined inline as opposed to in a standalone file.
             section_contents.extend_from_slice(b"\x04");
-            let vis_name = format!("pretty-printer-{}-{}\n", crate_name.as_str(), index);
+            let vis_name = format!("pretty-printer-{}-{}\n", crate_name, index);
             section_contents.extend_from_slice(vis_name.as_bytes());
             section_contents.extend_from_slice(&visualizer.src);
 
diff --git a/compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs b/compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs
index d5f39a45670..d87117dffdc 100644
--- a/compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs
+++ b/compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs
@@ -42,7 +42,6 @@ use rustc_span::{self, FileNameDisplayPreference, SourceFile};
 use rustc_symbol_mangling::typeid_for_trait_ref;
 use rustc_target::abi::{Align, Size};
 use smallvec::smallvec;
-use tracing::debug;
 
 use libc::{c_char, c_longlong, c_uint};
 use std::borrow::Cow;
@@ -51,7 +50,6 @@ use std::hash::{Hash, Hasher};
 use std::iter;
 use std::path::{Path, PathBuf};
 use std::ptr;
-use tracing::instrument;
 
 impl PartialEq for llvm::Metadata {
     fn eq(&self, other: &Self) -> bool {
@@ -114,6 +112,7 @@ macro_rules! return_if_di_node_created_in_meantime {
 }
 
 /// Extract size and alignment from a TyAndLayout.
+#[inline]
 fn size_and_align_of<'tcx>(ty_and_layout: TyAndLayout<'tcx>) -> (Size, Align) {
     (ty_and_layout.size, ty_and_layout.align.abi)
 }
@@ -824,7 +823,7 @@ pub fn build_compile_unit_di_node<'ll, 'tcx>(
         output_filenames
             .split_dwarf_path(
                 tcx.sess.split_debuginfo(),
-                tcx.sess.opts.debugging_opts.split_dwarf_kind,
+                tcx.sess.opts.unstable_opts.split_dwarf_kind,
                 Some(codegen_unit_name),
             )
             // We get a path relative to the working directory from split_dwarf_path
@@ -881,15 +880,15 @@ pub fn build_compile_unit_di_node<'ll, 'tcx>(
             split_name.len(),
             kind,
             0,
-            tcx.sess.opts.debugging_opts.split_dwarf_inlining,
+            tcx.sess.opts.unstable_opts.split_dwarf_inlining,
         );
 
-        if tcx.sess.opts.debugging_opts.profile {
+        if tcx.sess.opts.unstable_opts.profile {
             let cu_desc_metadata =
                 llvm::LLVMRustMetadataAsValue(debug_context.llcontext, unit_metadata);
             let default_gcda_path = &output_filenames.with_extension("gcda");
             let gcda_path =
-                tcx.sess.opts.debugging_opts.profile_emit.as_ref().unwrap_or(default_gcda_path);
+                tcx.sess.opts.unstable_opts.profile_emit.as_ref().unwrap_or(default_gcda_path);
 
             let gcov_cu_info = [
                 path_to_mdstring(debug_context.llcontext, &output_filenames.with_extension("gcno")),
@@ -999,7 +998,7 @@ fn build_struct_type_di_node<'ll, 'tcx>(
                 .iter()
                 .enumerate()
                 .map(|(i, f)| {
-                    let field_name = if variant_def.ctor_kind == CtorKind::Fn {
+                    let field_name = if variant_def.ctor_kind() == Some(CtorKind::Fn) {
                         // This is a tuple struct
                         tuple_field_name(i)
                     } else {
@@ -1420,7 +1419,7 @@ fn build_vtable_type_di_node<'ll, 'tcx>(
         cx,
         type_map::stub(
             cx,
-            Stub::VtableTy { vtable_holder },
+            Stub::VTableTy { vtable_holder },
             unique_type_id,
             &vtable_type_name,
             (size, pointer_align),
@@ -1499,24 +1498,18 @@ fn vcall_visibility_metadata<'ll, 'tcx>(
         // If there is not LTO and the visibility in public, we have to assume that the vtable can
         // be seen from anywhere. With multiple CGUs, the vtable is quasi-public.
         (Lto::No | Lto::ThinLocal, Visibility::Public, _)
-        | (Lto::No, Visibility::Restricted(_) | Visibility::Invisible, false) => {
-            VCallVisibility::Public
-        }
+        | (Lto::No, Visibility::Restricted(_), false) => VCallVisibility::Public,
         // With LTO and a quasi-public visibility, the usages of the functions of the vtable are
         // all known by the `LinkageUnit`.
         // FIXME: LLVM only supports this optimization for `Lto::Fat` currently. Once it also
         // supports `Lto::Thin` the `VCallVisibility` may have to be adjusted for those.
         (Lto::Fat | Lto::Thin, Visibility::Public, _)
-        | (
-            Lto::ThinLocal | Lto::Thin | Lto::Fat,
-            Visibility::Restricted(_) | Visibility::Invisible,
-            false,
-        ) => VCallVisibility::LinkageUnit,
+        | (Lto::ThinLocal | Lto::Thin | Lto::Fat, Visibility::Restricted(_), false) => {
+            VCallVisibility::LinkageUnit
+        }
         // If there is only one CGU, private vtables can only be seen by that CGU/translation unit
         // and therefore we know of all usages of functions in the vtable.
-        (_, Visibility::Restricted(_) | Visibility::Invisible, true) => {
-            VCallVisibility::TranslationUnit
-        }
+        (_, Visibility::Restricted(_), true) => VCallVisibility::TranslationUnit,
     };
 
     let trait_ref_typeid = typeid_for_trait_ref(cx.tcx, trait_ref);
@@ -1559,7 +1552,7 @@ pub fn create_vtable_di_node<'ll, 'tcx>(
 ) {
     // FIXME(flip1995): The virtual function elimination optimization only works with full LTO in
     // LLVM at the moment.
-    if cx.sess().opts.debugging_opts.virtual_function_elimination && cx.sess().lto() == Lto::Fat {
+    if cx.sess().opts.unstable_opts.virtual_function_elimination && cx.sess().lto() == Lto::Fat {
         vcall_visibility_metadata(cx, ty, poly_trait_ref, vtable);
     }
 
diff --git a/compiler/rustc_codegen_llvm/src/debuginfo/metadata/enums/cpp_like.rs b/compiler/rustc_codegen_llvm/src/debuginfo/metadata/enums/cpp_like.rs
index d6e2c8ccdf4..53e8a291d1e 100644
--- a/compiler/rustc_codegen_llvm/src/debuginfo/metadata/enums/cpp_like.rs
+++ b/compiler/rustc_codegen_llvm/src/debuginfo/metadata/enums/cpp_like.rs
@@ -1,19 +1,21 @@
 use std::borrow::Cow;
 
 use libc::c_uint;
-use rustc_codegen_ssa::debuginfo::{
-    type_names::compute_debuginfo_type_name, wants_c_like_enum_debuginfo,
+use rustc_codegen_ssa::{
+    debuginfo::{type_names::compute_debuginfo_type_name, wants_c_like_enum_debuginfo},
+    traits::ConstMethods,
 };
+
+use rustc_index::vec::IndexVec;
 use rustc_middle::{
     bug,
     ty::{
         self,
         layout::{LayoutOf, TyAndLayout},
-        util::Discr,
-        AdtDef, GeneratorSubsts,
+        AdtDef, GeneratorSubsts, Ty,
     },
 };
-use rustc_target::abi::{Size, TagEncoding, VariantIdx, Variants};
+use rustc_target::abi::{Align, Endian, Size, TagEncoding, VariantIdx, Variants};
 use smallvec::smallvec;
 
 use crate::{
@@ -21,9 +23,9 @@ use crate::{
     debuginfo::{
         metadata::{
             build_field_di_node, closure_saved_names_of_captured_variables,
-            enums::tag_base_type,
-            file_metadata, generator_layout_and_saved_local_names, size_and_align_of,
-            type_map::{self, UniqueTypeId},
+            enums::{tag_base_type, DiscrResult},
+            file_metadata, generator_layout_and_saved_local_names, size_and_align_of, type_di_node,
+            type_map::{self, Stub, UniqueTypeId},
             unknown_file_metadata, DINodeCreationResult, SmallVec, NO_GENERICS, NO_SCOPE_METADATA,
             UNKNOWN_LINE_NUMBER,
         },
@@ -35,59 +37,161 @@ use crate::{
     },
 };
 
-/// In CPP-like mode, we generate a union of structs for each variant and an
-/// explicit discriminant field roughly equivalent to the following C/C++ code:
+// The names of the associated constants in each variant wrapper struct.
+// These have to match up with the names being used in `intrinsic.natvis`.
+const ASSOC_CONST_DISCR_NAME: &str = "NAME";
+const ASSOC_CONST_DISCR_EXACT: &str = "DISCR_EXACT";
+const ASSOC_CONST_DISCR_BEGIN: &str = "DISCR_BEGIN";
+const ASSOC_CONST_DISCR_END: &str = "DISCR_END";
+
+const ASSOC_CONST_DISCR128_EXACT_LO: &str = "DISCR128_EXACT_LO";
+const ASSOC_CONST_DISCR128_EXACT_HI: &str = "DISCR128_EXACT_HI";
+const ASSOC_CONST_DISCR128_BEGIN_LO: &str = "DISCR128_BEGIN_LO";
+const ASSOC_CONST_DISCR128_BEGIN_HI: &str = "DISCR128_BEGIN_HI";
+const ASSOC_CONST_DISCR128_END_LO: &str = "DISCR128_END_LO";
+const ASSOC_CONST_DISCR128_END_HI: &str = "DISCR128_END_HI";
+
+// The name of the tag field in the top-level union
+const TAG_FIELD_NAME: &str = "tag";
+const TAG_FIELD_NAME_128_LO: &str = "tag128_lo";
+const TAG_FIELD_NAME_128_HI: &str = "tag128_hi";
+
+// We assign a "virtual" discriminant value to the sole variant of
+// a single-variant enum.
+const SINGLE_VARIANT_VIRTUAL_DISR: u64 = 0;
+
+/// In CPP-like mode, we generate a union with a field for each variant and an
+/// explicit tag field. The field of each variant has a struct type
+/// that encodes the discrimiant of the variant and it's data layout.
+/// The union also has a nested enumeration type that is only used for encoding
+/// variant names in an efficient way. Its enumerator values do _not_ correspond
+/// to the enum's discriminant values.
+/// It's roughly equivalent to the following C/C++ code:
 ///
 /// ```c
-/// union enum$<{fully-qualified-name}> {
-///   struct {variant 0 name} {
-///     <variant 0 fields>
+/// union enum2$<{fully-qualified-name}> {
+///   struct Variant0 {
+///     struct {name-of-variant-0} {
+///        <variant 0 fields>
+///     } value;
+///
+///     static VariantNames NAME = {name-of-variant-0};
+///     static int_type DISCR_EXACT = {discriminant-of-variant-0};
 ///   } variant0;
+///
 ///   <other variant structs>
-///   {name} discriminant;
+///
+///   int_type tag;
+///
+///   enum VariantNames {
+///      <name-of-variant-0> = 0, // The numeric values are variant index,
+///      <name-of-variant-1> = 1, // not discriminant values.
+///      <name-of-variant-2> = 2,
+///      ...
+///   }
 /// }
 /// ```
 ///
-/// As you can see, the type name is wrapped `enum$`. This way we can have a
-/// single NatVis rule for handling all enums.
+/// As you can see, the type name is wrapped in `enum2$<_>`. This way we can
+/// have a single NatVis rule for handling all enums. The `2` in `enum2$<_>`
+/// is an encoding version tag, so that debuggers can decide to decode this
+/// differently than the previous `enum$<_>` encoding emitted by earlier
+/// compiler versions.
 ///
-/// At the LLVM IR level this looks like
+/// Niche-tag enums have one special variant, usually called the
+/// "untagged variant". This variant has a field that
+/// doubles as the tag of the enum. The variant is active when the value of
+/// that field is within a pre-defined range. Therefore the variant struct
+/// has a `DISCR_BEGIN` and `DISCR_END` field instead of `DISCR_EXACT` in
+/// that case. Both `DISCR_BEGIN` and `DISCR_END` are inclusive bounds.
+/// Note that these ranges can wrap around, so that `DISCR_END < DISCR_BEGIN`.
 ///
-/// ```txt
-///       DW_TAG_union_type              (top-level type for enum)
-///         DW_TAG_member                    (member for variant 1)
-///         DW_TAG_member                    (member for variant 2)
-///         DW_TAG_member                    (member for variant 3)
-///         DW_TAG_structure_type            (type of variant 1)
-///         DW_TAG_structure_type            (type of variant 2)
-///         DW_TAG_structure_type            (type of variant 3)
-///         DW_TAG_enumeration_type          (type of tag)
-/// ```
+/// Single-variant enums don't actually have a tag field. In this case we
+/// emit a static tag field (that always has the value 0) so we can use the
+/// same representation (and NatVis).
 ///
-/// The above encoding applies for enums with a direct tag. For niche-tag we have to do things
-/// differently in order to allow a NatVis visualizer to extract all the information needed:
-/// We generate a union of two fields, one for the dataful variant
-/// and one that just points to the discriminant (which is some field within the dataful variant).
-/// We also create a DW_TAG_enumeration_type DIE that contains tag values for the non-dataful
-/// variants and make the discriminant field that type. We then use NatVis to render the enum type
-/// correctly in Windbg/VS. This will generate debuginfo roughly equivalent to the following C:
+/// For niche-layout enums it's possible to have a 128-bit tag. NatVis, VS, and
+/// WinDbg (the main targets for CPP-like debuginfo at the moment) don't support
+/// 128-bit integers, so all values involved get split into two 64-bit fields.
+/// Instead of the `tag` field, we generate two fields `tag128_lo` and `tag128_hi`,
+/// Instead of `DISCR_EXACT`, we generate `DISCR128_EXACT_LO` and `DISCR128_EXACT_HI`,
+/// and so on.
 ///
-/// ```c
-/// union enum$<{name}, {min niche}, {max niche}, {dataful variant name}> {
-///   struct <dataful variant name> {
-///     <fields in dataful variant>
-///   } dataful_variant;
-///   enum Discriminant$ {
-///     <non-dataful variants>
-///   } discriminant;
+///
+/// The following pseudocode shows how to decode an enum value in a debugger:
+///
+/// ```text
+///
+/// fn find_active_variant(enum_value) -> (VariantName, VariantValue) {
+///     let is_128_bit = enum_value.has_field("tag128_lo");
+///
+///     if !is_128_bit {
+///         // Note: `tag` can be a static field for enums with only one
+///         //       inhabited variant.
+///         let tag = enum_value.field("tag").value;
+///
+///         // For each variant, check if it is a match. Only one of them will match,
+///         // so if we find it we can return it immediately.
+///         for variant_field in enum_value.fields().filter(|f| f.name.starts_with("variant")) {
+///             if variant_field.has_field("DISCR_EXACT") {
+///                 // This variant corresponds to a single tag value
+///                 if variant_field.field("DISCR_EXACT").value == tag {
+///                     return (variant_field.field("NAME"), variant_field.value);
+///                 }
+///             } else {
+///                 // This is a range variant
+///                 let begin = variant_field.field("DISCR_BEGIN");
+///                 let end = variant_field.field("DISCR_END");
+///
+///                 if is_in_range(tag, begin, end) {
+///                     return (variant_field.field("NAME"), variant_field.value);
+///                 }
+///             }
+///         }
+///     } else {
+///         // Basically the same as with smaller tags, we just have to
+///         // stitch the values together.
+///         let tag: u128 = (enum_value.field("tag128_lo").value as u128) |
+///                         (enum_value.field("tag128_hi").value as u128 << 64);
+///
+///         for variant_field in enum_value.fields().filter(|f| f.name.starts_with("variant")) {
+///             if variant_field.has_field("DISCR128_EXACT_LO") {
+///                 let discr_exact = (variant_field.field("DISCR128_EXACT_LO" as u128) |
+///                                   (variant_field.field("DISCR128_EXACT_HI") as u128 << 64);
+///
+///                 // This variant corresponds to a single tag value
+///                 if discr_exact.value == tag {
+///                     return (variant_field.field("NAME"), variant_field.value);
+///                 }
+///             } else {
+///                 // This is a range variant
+///                 let begin = (variant_field.field("DISCR128_BEGIN_LO").value as u128) |
+///                             (variant_field.field("DISCR128_BEGIN_HI").value as u128 << 64);
+///                 let end = (variant_field.field("DISCR128_END_LO").value as u128) |
+///                           (variant_field.field("DISCR128_END_HI").value as u128 << 64);
+///
+///                 if is_in_range(tag, begin, end) {
+///                     return (variant_field.field("NAME"), variant_field.value);
+///                 }
+///             }
+///         }
+///     }
+///
+///     // We should have found an active variant at this point.
+///     unreachable!();
 /// }
-/// ```
 ///
-/// The NatVis in `intrinsic.natvis` matches on the type name `enum$<*, *, *, *>`
-/// and evaluates `this.discriminant`. If the value is between the min niche and max
-/// niche, then the enum is in the dataful variant and `this.dataful_variant` is
-/// rendered. Otherwise, the enum is in one of the non-dataful variants. In that
-/// case, we just need to render the name of the `this.discriminant` enum.
+/// // Check if a value is within the given range
+/// // (where the range might wrap around the value space)
+/// fn is_in_range(value, start, end) -> bool {
+///     if start < end {
+///         value >= start && value <= end
+///     } else {
+///         value >= start || value <= end
+///     }
+/// }
+///
+/// ```
 pub(super) fn build_enum_type_di_node<'ll, 'tcx>(
     cx: &CodegenCx<'ll, 'tcx>,
     unique_type_id: UniqueTypeId<'tcx>,
@@ -135,27 +239,28 @@ pub(super) fn build_enum_type_di_node<'ll, 'tcx>(
                     ref variants,
                     tag_field,
                     ..
-                } => build_union_fields_for_direct_tag_enum(
+                } => build_union_fields_for_enum(
                     cx,
                     enum_adt_def,
                     enum_type_and_layout,
                     enum_type_di_node,
-                    &mut variants.indices(),
+                    variants.indices(),
                     tag_field,
+                    None,
                 ),
                 Variants::Multiple {
-                    tag_encoding: TagEncoding::Niche { dataful_variant, .. },
+                    tag_encoding: TagEncoding::Niche { untagged_variant, .. },
                     ref variants,
                     tag_field,
                     ..
-                } => build_union_fields_for_niche_tag_enum(
+                } => build_union_fields_for_enum(
                     cx,
                     enum_adt_def,
                     enum_type_and_layout,
                     enum_type_di_node,
-                    dataful_variant,
-                    &mut variants.indices(),
+                    variants.indices(),
                     tag_field,
+                    Some(untagged_variant),
                 ),
             }
         },
@@ -217,137 +322,344 @@ fn build_single_variant_union_fields<'ll, 'tcx>(
     let variant_layout = enum_type_and_layout.for_variant(cx, variant_index);
     let variant_struct_type_di_node = super::build_enum_variant_struct_type_di_node(
         cx,
-        enum_type_and_layout.ty,
+        enum_type_and_layout,
         enum_type_di_node,
         variant_index,
         enum_adt_def.variant(variant_index),
         variant_layout,
     );
 
-    // NOTE: The field name of the union is the same as the variant name, not "variant0".
-    let variant_name = enum_adt_def.variant(variant_index).name.as_str();
+    let tag_base_type = cx.tcx.types.u32;
+    let tag_base_type_di_node = type_di_node(cx, tag_base_type);
+    let tag_base_type_align = cx.align_of(tag_base_type);
+
+    let variant_names_type_di_node = build_variant_names_type_di_node(
+        cx,
+        enum_type_di_node,
+        std::iter::once((
+            variant_index,
+            Cow::from(enum_adt_def.variant(variant_index).name.as_str()),
+        )),
+    );
 
-    smallvec![build_field_di_node(
+    let variant_struct_type_wrapper_di_node = build_variant_struct_wrapper_type_di_node(
         cx,
+        enum_type_and_layout,
         enum_type_di_node,
-        variant_name,
-        // NOTE: We use the size and align of the entire type, not from variant_layout
-        //       since the later is sometimes smaller (if it has fewer fields).
-        size_and_align_of(enum_type_and_layout),
-        Size::ZERO,
-        DIFlags::FlagZero,
+        variant_index,
+        None,
         variant_struct_type_di_node,
-    )]
+        variant_names_type_di_node,
+        tag_base_type_di_node,
+        tag_base_type,
+        DiscrResult::NoDiscriminant,
+    );
+
+    smallvec![
+        build_field_di_node(
+            cx,
+            enum_type_di_node,
+            &variant_union_field_name(variant_index),
+            // NOTE: We use the size and align of the entire type, not from variant_layout
+            //       since the later is sometimes smaller (if it has fewer fields).
+            size_and_align_of(enum_type_and_layout),
+            Size::ZERO,
+            DIFlags::FlagZero,
+            variant_struct_type_wrapper_di_node,
+        ),
+        unsafe {
+            llvm::LLVMRustDIBuilderCreateStaticMemberType(
+                DIB(cx),
+                enum_type_di_node,
+                TAG_FIELD_NAME.as_ptr().cast(),
+                TAG_FIELD_NAME.len(),
+                unknown_file_metadata(cx),
+                UNKNOWN_LINE_NUMBER,
+                variant_names_type_di_node,
+                DIFlags::FlagZero,
+                Some(cx.const_u64(SINGLE_VARIANT_VIRTUAL_DISR)),
+                tag_base_type_align.bits() as u32,
+            )
+        }
+    ]
 }
 
-fn build_union_fields_for_direct_tag_enum<'ll, 'tcx>(
+fn build_union_fields_for_enum<'ll, 'tcx>(
     cx: &CodegenCx<'ll, 'tcx>,
     enum_adt_def: AdtDef<'tcx>,
     enum_type_and_layout: TyAndLayout<'tcx>,
     enum_type_di_node: &'ll DIType,
-    variant_indices: &mut dyn Iterator<Item = VariantIdx>,
+    variant_indices: impl Iterator<Item = VariantIdx> + Clone,
     tag_field: usize,
+    untagged_variant_index: Option<VariantIdx>,
 ) -> SmallVec<&'ll DIType> {
+    let tag_base_type = super::tag_base_type(cx, enum_type_and_layout);
+
+    let variant_names_type_di_node = build_variant_names_type_di_node(
+        cx,
+        enum_type_di_node,
+        variant_indices.clone().map(|variant_index| {
+            let variant_name = Cow::from(enum_adt_def.variant(variant_index).name.as_str());
+            (variant_index, variant_name)
+        }),
+    );
+
     let variant_field_infos: SmallVec<VariantFieldInfo<'ll>> = variant_indices
         .map(|variant_index| {
             let variant_layout = enum_type_and_layout.for_variant(cx, variant_index);
 
+            let variant_def = enum_adt_def.variant(variant_index);
+
+            let variant_struct_type_di_node = super::build_enum_variant_struct_type_di_node(
+                cx,
+                enum_type_and_layout,
+                enum_type_di_node,
+                variant_index,
+                variant_def,
+                variant_layout,
+            );
+
             VariantFieldInfo {
                 variant_index,
-                variant_struct_type_di_node: super::build_enum_variant_struct_type_di_node(
-                    cx,
-                    enum_type_and_layout.ty,
-                    enum_type_di_node,
-                    variant_index,
-                    enum_adt_def.variant(variant_index),
-                    variant_layout,
-                ),
+                variant_struct_type_di_node,
                 source_info: None,
+                discr: super::compute_discriminant_value(cx, enum_type_and_layout, variant_index),
             }
         })
         .collect();
 
-    let discr_type_name = cx.tcx.item_name(enum_adt_def.did());
-    let tag_base_type = super::tag_base_type(cx, enum_type_and_layout);
-    let discr_type_di_node = super::build_enumeration_type_di_node(
-        cx,
-        discr_type_name.as_str(),
-        tag_base_type,
-        &mut enum_adt_def.discriminants(cx.tcx).map(|(variant_index, discr)| {
-            (discr, Cow::from(enum_adt_def.variant(variant_index).name.as_str()))
-        }),
-        enum_type_di_node,
-    );
-
     build_union_fields_for_direct_tag_enum_or_generator(
         cx,
         enum_type_and_layout,
         enum_type_di_node,
         &variant_field_infos,
-        discr_type_di_node,
+        variant_names_type_di_node,
+        tag_base_type,
         tag_field,
+        untagged_variant_index,
     )
 }
 
-fn build_union_fields_for_niche_tag_enum<'ll, 'tcx>(
+// The base type of the VariantNames DW_AT_enumeration_type is always the same.
+// It has nothing to do with the tag of the enum and just has to be big enough
+// to hold all variant names.
+fn variant_names_enum_base_type<'ll, 'tcx>(cx: &CodegenCx<'ll, 'tcx>) -> Ty<'tcx> {
+    cx.tcx.types.u32
+}
+
+/// This function builds a DW_AT_enumeration_type that contains an entry for
+/// each variant. Note that this has nothing to do with the discriminant. The
+/// numeric value of each enumerator corresponds to the variant index. The
+/// type is only used for efficiently encoding the name of each variant in
+/// debuginfo.
+fn build_variant_names_type_di_node<'ll, 'tcx>(
     cx: &CodegenCx<'ll, 'tcx>,
-    enum_adt_def: AdtDef<'tcx>,
-    enum_type_and_layout: TyAndLayout<'tcx>,
-    enum_type_di_node: &'ll DIType,
-    dataful_variant_index: VariantIdx,
-    variant_indices: &mut dyn Iterator<Item = VariantIdx>,
-    tag_field: usize,
-) -> SmallVec<&'ll DIType> {
-    let dataful_variant_struct_type_di_node = super::build_enum_variant_struct_type_di_node(
+    containing_scope: &'ll DIType,
+    variants: impl Iterator<Item = (VariantIdx, Cow<'tcx, str>)>,
+) -> &'ll DIType {
+    // Create an enumerator for each variant.
+    super::build_enumeration_type_di_node(
         cx,
-        enum_type_and_layout.ty,
-        enum_type_di_node,
-        dataful_variant_index,
-        &enum_adt_def.variant(dataful_variant_index),
-        enum_type_and_layout.for_variant(cx, dataful_variant_index),
-    );
+        "VariantNames",
+        variant_names_enum_base_type(cx),
+        variants.map(|(variant_index, variant_name)| (variant_name, variant_index.as_u32().into())),
+        containing_scope,
+    )
+}
 
-    let tag_base_type = super::tag_base_type(cx, enum_type_and_layout);
-    // Create an DW_TAG_enumerator for each variant except the dataful one.
-    let discr_type_di_node = super::build_enumeration_type_di_node(
+fn build_variant_struct_wrapper_type_di_node<'ll, 'tcx>(
+    cx: &CodegenCx<'ll, 'tcx>,
+    enum_or_generator_type_and_layout: TyAndLayout<'tcx>,
+    enum_or_generator_type_di_node: &'ll DIType,
+    variant_index: VariantIdx,
+    untagged_variant_index: Option<VariantIdx>,
+    variant_struct_type_di_node: &'ll DIType,
+    variant_names_type_di_node: &'ll DIType,
+    tag_base_type_di_node: &'ll DIType,
+    tag_base_type: Ty<'tcx>,
+    discr: DiscrResult,
+) -> &'ll DIType {
+    type_map::build_type_with_children(
         cx,
-        "Discriminant$",
-        tag_base_type,
-        &mut variant_indices.filter_map(|variant_index| {
-            if let Some(discr_val) =
-                super::compute_discriminant_value(cx, enum_type_and_layout, variant_index)
-            {
-                let discr = Discr { val: discr_val as u128, ty: tag_base_type };
-                let variant_name = Cow::from(enum_adt_def.variant(variant_index).name.as_str());
-                Some((discr, variant_name))
-            } else {
-                debug_assert_eq!(variant_index, dataful_variant_index);
-                None
-            }
-        }),
-        enum_type_di_node,
-    );
-
-    smallvec![
-        build_field_di_node(
-            cx,
-            enum_type_di_node,
-            "dataful_variant",
-            size_and_align_of(enum_type_and_layout),
-            Size::ZERO,
-            DIFlags::FlagZero,
-            dataful_variant_struct_type_di_node,
-        ),
-        build_field_di_node(
+        type_map::stub(
             cx,
-            enum_type_di_node,
-            "discriminant",
-            cx.size_and_align_of(tag_base_type),
-            enum_type_and_layout.fields.offset(tag_field),
+            Stub::Struct,
+            UniqueTypeId::for_enum_variant_struct_type_wrapper(
+                cx.tcx,
+                enum_or_generator_type_and_layout.ty,
+                variant_index,
+            ),
+            &variant_struct_wrapper_type_name(variant_index),
+            // NOTE: We use size and align of enum_type, not from variant_layout:
+            size_and_align_of(enum_or_generator_type_and_layout),
+            Some(enum_or_generator_type_di_node),
             DIFlags::FlagZero,
-            discr_type_di_node,
         ),
-    ]
+        |cx, wrapper_struct_type_di_node| {
+            enum DiscrKind {
+                Exact(u64),
+                Exact128(u128),
+                Range(u64, u64),
+                Range128(u128, u128),
+            }
+
+            let (tag_base_type_size, tag_base_type_align) = cx.size_and_align_of(tag_base_type);
+            let is_128_bits = tag_base_type_size.bits() > 64;
+
+            let discr = match discr {
+                DiscrResult::NoDiscriminant => DiscrKind::Exact(SINGLE_VARIANT_VIRTUAL_DISR),
+                DiscrResult::Value(discr_val) => {
+                    if is_128_bits {
+                        DiscrKind::Exact128(discr_val)
+                    } else {
+                        debug_assert_eq!(discr_val, discr_val as u64 as u128);
+                        DiscrKind::Exact(discr_val as u64)
+                    }
+                }
+                DiscrResult::Range(min, max) => {
+                    assert_eq!(Some(variant_index), untagged_variant_index);
+                    if is_128_bits {
+                        DiscrKind::Range128(min, max)
+                    } else {
+                        debug_assert_eq!(min, min as u64 as u128);
+                        debug_assert_eq!(max, max as u64 as u128);
+                        DiscrKind::Range(min as u64, max as u64)
+                    }
+                }
+            };
+
+            let mut fields = SmallVec::new();
+
+            // We always have a field for the value
+            fields.push(build_field_di_node(
+                cx,
+                wrapper_struct_type_di_node,
+                "value",
+                size_and_align_of(enum_or_generator_type_and_layout),
+                Size::ZERO,
+                DIFlags::FlagZero,
+                variant_struct_type_di_node,
+            ));
+
+            let build_assoc_const =
+                |name: &str, type_di_node: &'ll DIType, value: u64, align: Align| unsafe {
+                    llvm::LLVMRustDIBuilderCreateStaticMemberType(
+                        DIB(cx),
+                        wrapper_struct_type_di_node,
+                        name.as_ptr().cast(),
+                        name.len(),
+                        unknown_file_metadata(cx),
+                        UNKNOWN_LINE_NUMBER,
+                        type_di_node,
+                        DIFlags::FlagZero,
+                        Some(cx.const_u64(value)),
+                        align.bits() as u32,
+                    )
+                };
+
+            // We also always have an associated constant for the discriminant value
+            // of the variant.
+            fields.push(build_assoc_const(
+                ASSOC_CONST_DISCR_NAME,
+                variant_names_type_di_node,
+                variant_index.as_u32() as u64,
+                cx.align_of(variant_names_enum_base_type(cx)),
+            ));
+
+            // Emit the discriminant value (or range) corresponding to the variant.
+            match discr {
+                DiscrKind::Exact(discr_val) => {
+                    fields.push(build_assoc_const(
+                        ASSOC_CONST_DISCR_EXACT,
+                        tag_base_type_di_node,
+                        discr_val,
+                        tag_base_type_align,
+                    ));
+                }
+                DiscrKind::Exact128(discr_val) => {
+                    let align = cx.align_of(cx.tcx.types.u64);
+                    let type_di_node = type_di_node(cx, cx.tcx.types.u64);
+                    let Split128 { hi, lo } = split_128(discr_val);
+
+                    fields.push(build_assoc_const(
+                        ASSOC_CONST_DISCR128_EXACT_LO,
+                        type_di_node,
+                        lo,
+                        align,
+                    ));
+
+                    fields.push(build_assoc_const(
+                        ASSOC_CONST_DISCR128_EXACT_HI,
+                        type_di_node,
+                        hi,
+                        align,
+                    ));
+                }
+                DiscrKind::Range(begin, end) => {
+                    fields.push(build_assoc_const(
+                        ASSOC_CONST_DISCR_BEGIN,
+                        tag_base_type_di_node,
+                        begin,
+                        tag_base_type_align,
+                    ));
+
+                    fields.push(build_assoc_const(
+                        ASSOC_CONST_DISCR_END,
+                        tag_base_type_di_node,
+                        end,
+                        tag_base_type_align,
+                    ));
+                }
+                DiscrKind::Range128(begin, end) => {
+                    let align = cx.align_of(cx.tcx.types.u64);
+                    let type_di_node = type_di_node(cx, cx.tcx.types.u64);
+                    let Split128 { hi: begin_hi, lo: begin_lo } = split_128(begin);
+                    let Split128 { hi: end_hi, lo: end_lo } = split_128(end);
+
+                    fields.push(build_assoc_const(
+                        ASSOC_CONST_DISCR128_BEGIN_HI,
+                        type_di_node,
+                        begin_hi,
+                        align,
+                    ));
+
+                    fields.push(build_assoc_const(
+                        ASSOC_CONST_DISCR128_BEGIN_LO,
+                        type_di_node,
+                        begin_lo,
+                        align,
+                    ));
+
+                    fields.push(build_assoc_const(
+                        ASSOC_CONST_DISCR128_END_HI,
+                        type_di_node,
+                        end_hi,
+                        align,
+                    ));
+
+                    fields.push(build_assoc_const(
+                        ASSOC_CONST_DISCR128_END_LO,
+                        type_di_node,
+                        end_lo,
+                        align,
+                    ));
+                }
+            }
+
+            fields
+        },
+        NO_GENERICS,
+    )
+    .di_node
+}
+
+struct Split128 {
+    hi: u64,
+    lo: u64,
+}
+
+fn split_128(value: u128) -> Split128 {
+    Split128 { hi: (value >> 64) as u64, lo: value as u64 }
 }
 
 fn build_union_fields_for_direct_tag_generator<'ll, 'tcx>(
@@ -369,6 +681,29 @@ fn build_union_fields_for_direct_tag_generator<'ll, 'tcx>(
 
     let common_upvar_names = closure_saved_names_of_captured_variables(cx.tcx, generator_def_id);
     let variant_range = generator_substs.variant_range(generator_def_id, cx.tcx);
+    let variant_count = (variant_range.start.as_u32()..variant_range.end.as_u32()).len();
+
+    let tag_base_type = tag_base_type(cx, generator_type_and_layout);
+
+    let variant_names_type_di_node = build_variant_names_type_di_node(
+        cx,
+        generator_type_di_node,
+        variant_range
+            .clone()
+            .map(|variant_index| (variant_index, GeneratorSubsts::variant_name(variant_index))),
+    );
+
+    let discriminants: IndexVec<VariantIdx, DiscrResult> = {
+        let discriminants_iter = generator_substs.discriminants(generator_def_id, cx.tcx);
+        let mut discriminants: IndexVec<VariantIdx, DiscrResult> =
+            IndexVec::with_capacity(variant_count);
+        for (variant_index, discr) in discriminants_iter {
+            // Assert that the index in the IndexMap matches up with the given VariantIdx.
+            assert_eq!(variant_index, discriminants.next_index());
+            discriminants.push(DiscrResult::Value(discr.val));
+        }
+        discriminants
+    };
 
     // Build the type node for each field.
     let variant_field_infos: SmallVec<VariantFieldInfo<'ll>> = variant_range
@@ -391,29 +726,24 @@ fn build_union_fields_for_direct_tag_generator<'ll, 'tcx>(
                 None
             };
 
-            VariantFieldInfo { variant_index, variant_struct_type_di_node, source_info }
+            VariantFieldInfo {
+                variant_index,
+                variant_struct_type_di_node,
+                source_info,
+                discr: discriminants[variant_index],
+            }
         })
         .collect();
 
-    let tag_base_type = tag_base_type(cx, generator_type_and_layout);
-    let discr_type_name = "Discriminant$";
-    let discr_type_di_node = super::build_enumeration_type_di_node(
-        cx,
-        discr_type_name,
-        tag_base_type,
-        &mut generator_substs
-            .discriminants(generator_def_id, cx.tcx)
-            .map(|(variant_index, discr)| (discr, GeneratorSubsts::variant_name(variant_index))),
-        generator_type_di_node,
-    );
-
     build_union_fields_for_direct_tag_enum_or_generator(
         cx,
         generator_type_and_layout,
         generator_type_di_node,
         &variant_field_infos[..],
-        discr_type_di_node,
+        variant_names_type_di_node,
+        tag_base_type,
         tag_field,
+        None,
     )
 }
 
@@ -425,8 +755,11 @@ fn build_union_fields_for_direct_tag_enum_or_generator<'ll, 'tcx>(
     enum_type_di_node: &'ll DIType,
     variant_field_infos: &[VariantFieldInfo<'ll>],
     discr_type_di_node: &'ll DIType,
+    tag_base_type: Ty<'tcx>,
     tag_field: usize,
+    untagged_variant_index: Option<VariantIdx>,
 ) -> SmallVec<&'ll DIType> {
+    let tag_base_type_di_node = type_di_node(cx, tag_base_type);
     let mut unions_fields = SmallVec::with_capacity(variant_field_infos.len() + 1);
 
     // We create a field in the union for each variant ...
@@ -438,6 +771,19 @@ fn build_union_fields_for_direct_tag_enum_or_generator<'ll, 'tcx>(
         let field_name = variant_union_field_name(variant_member_info.variant_index);
         let (size, align) = size_and_align_of(enum_type_and_layout);
 
+        let variant_struct_type_wrapper = build_variant_struct_wrapper_type_di_node(
+            cx,
+            enum_type_and_layout,
+            enum_type_di_node,
+            variant_member_info.variant_index,
+            untagged_variant_index,
+            variant_member_info.variant_struct_type_di_node,
+            discr_type_di_node,
+            tag_base_type_di_node,
+            tag_base_type,
+            variant_member_info.discr,
+        );
+
         // We use LLVMRustDIBuilderCreateMemberType() member type directly because
         // the build_field_di_node() function does not support specifying a source location,
         // which is something that we don't do anywhere else.
@@ -456,7 +802,7 @@ fn build_union_fields_for_direct_tag_enum_or_generator<'ll, 'tcx>(
                 // Union fields are always at offset zero
                 Size::ZERO.bits(),
                 DIFlags::FlagZero,
-                variant_member_info.variant_struct_type_di_node,
+                variant_struct_type_wrapper,
             )
         }
     }));
@@ -466,16 +812,53 @@ fn build_union_fields_for_direct_tag_enum_or_generator<'ll, 'tcx>(
         cx.size_and_align_of(super::tag_base_type(cx, enum_type_and_layout))
     );
 
-    // ... and a field for the discriminant.
-    unions_fields.push(build_field_di_node(
-        cx,
-        enum_type_di_node,
-        "discriminant",
-        cx.size_and_align_of(enum_type_and_layout.field(cx, tag_field).ty),
-        enum_type_and_layout.fields.offset(tag_field),
-        DIFlags::FlagZero,
-        discr_type_di_node,
-    ));
+    // ... and a field for the tag. If the tag is 128 bits wide, this will actually
+    // be two 64-bit fields.
+    let is_128_bits = cx.size_of(tag_base_type).bits() > 64;
+
+    if is_128_bits {
+        let type_di_node = type_di_node(cx, cx.tcx.types.u64);
+        let size_and_align = cx.size_and_align_of(cx.tcx.types.u64);
+
+        let (lo_offset, hi_offset) = match cx.tcx.data_layout.endian {
+            Endian::Little => (0, 8),
+            Endian::Big => (8, 0),
+        };
+
+        let tag_field_offset = enum_type_and_layout.fields.offset(tag_field).bytes();
+        let lo_offset = Size::from_bytes(tag_field_offset + lo_offset);
+        let hi_offset = Size::from_bytes(tag_field_offset + hi_offset);
+
+        unions_fields.push(build_field_di_node(
+            cx,
+            enum_type_di_node,
+            TAG_FIELD_NAME_128_LO,
+            size_and_align,
+            lo_offset,
+            DIFlags::FlagZero,
+            type_di_node,
+        ));
+
+        unions_fields.push(build_field_di_node(
+            cx,
+            enum_type_di_node,
+            TAG_FIELD_NAME_128_HI,
+            size_and_align,
+            hi_offset,
+            DIFlags::FlagZero,
+            type_di_node,
+        ));
+    } else {
+        unions_fields.push(build_field_di_node(
+            cx,
+            enum_type_di_node,
+            TAG_FIELD_NAME,
+            cx.size_and_align_of(enum_type_and_layout.field(cx, tag_field).ty),
+            enum_type_and_layout.fields.offset(tag_field),
+            DIFlags::FlagZero,
+            tag_base_type_di_node,
+        ));
+    }
 
     unions_fields
 }
@@ -485,6 +868,7 @@ struct VariantFieldInfo<'ll> {
     variant_index: VariantIdx,
     variant_struct_type_di_node: &'ll DIType,
     source_info: Option<(&'ll DIFile, c_uint)>,
+    discr: DiscrResult,
 }
 
 fn variant_union_field_name(variant_index: VariantIdx) -> Cow<'static, str> {
@@ -512,3 +896,29 @@ fn variant_union_field_name(variant_index: VariantIdx) -> Cow<'static, str> {
         .map(|&s| Cow::from(s))
         .unwrap_or_else(|| format!("variant{}", variant_index.as_usize()).into())
 }
+
+fn variant_struct_wrapper_type_name(variant_index: VariantIdx) -> Cow<'static, str> {
+    const PRE_ALLOCATED: [&str; 16] = [
+        "Variant0",
+        "Variant1",
+        "Variant2",
+        "Variant3",
+        "Variant4",
+        "Variant5",
+        "Variant6",
+        "Variant7",
+        "Variant8",
+        "Variant9",
+        "Variant10",
+        "Variant11",
+        "Variant12",
+        "Variant13",
+        "Variant14",
+        "Variant15",
+    ];
+
+    PRE_ALLOCATED
+        .get(variant_index.as_usize())
+        .map(|&s| Cow::from(s))
+        .unwrap_or_else(|| format!("Variant{}", variant_index.as_usize()).into())
+}
diff --git a/compiler/rustc_codegen_llvm/src/debuginfo/metadata/enums/mod.rs b/compiler/rustc_codegen_llvm/src/debuginfo/metadata/enums/mod.rs
index 73e01d0453b..564ab351bd4 100644
--- a/compiler/rustc_codegen_llvm/src/debuginfo/metadata/enums/mod.rs
+++ b/compiler/rustc_codegen_llvm/src/debuginfo/metadata/enums/mod.rs
@@ -10,7 +10,6 @@ use rustc_middle::{
     ty::{
         self,
         layout::{IntegerExt, LayoutOf, PrimitiveExt, TyAndLayout},
-        util::Discr,
         AdtDef, GeneratorSubsts, Ty, VariantDef,
     },
 };
@@ -90,8 +89,9 @@ fn build_c_style_enum_di_node<'ll, 'tcx>(
             cx,
             &compute_debuginfo_type_name(cx.tcx, enum_type_and_layout.ty, false),
             tag_base_type(cx, enum_type_and_layout),
-            &mut enum_adt_def.discriminants(cx.tcx).map(|(variant_index, discr)| {
-                (discr, Cow::from(enum_adt_def.variant(variant_index).name.as_str()))
+            enum_adt_def.discriminants(cx.tcx).map(|(variant_index, discr)| {
+                let name = Cow::from(enum_adt_def.variant(variant_index).name.as_str());
+                (name, discr.val)
             }),
             containing_scope,
         ),
@@ -145,14 +145,11 @@ fn tag_base_type<'ll, 'tcx>(
 /// This is a helper function and does not register anything in the type map by itself.
 ///
 /// `variants` is an iterator of (discr-value, variant-name).
-///
-// NOTE: Handling of discriminant values is somewhat inconsistent. They can appear as u128,
-//       u64, and i64. Here everything gets mapped to i64 because that's what LLVM's API expects.
 fn build_enumeration_type_di_node<'ll, 'tcx>(
     cx: &CodegenCx<'ll, 'tcx>,
     type_name: &str,
     base_type: Ty<'tcx>,
-    variants: &mut dyn Iterator<Item = (Discr<'tcx>, Cow<'tcx, str>)>,
+    enumerators: impl Iterator<Item = (Cow<'tcx, str>, u128)>,
     containing_scope: &'ll DIType,
 ) -> &'ll DIType {
     let is_unsigned = match base_type.kind() {
@@ -160,24 +157,22 @@ fn build_enumeration_type_di_node<'ll, 'tcx>(
         ty::Uint(_) => true,
         _ => bug!("build_enumeration_type_di_node() called with non-integer tag type."),
     };
+    let (size, align) = cx.size_and_align_of(base_type);
 
-    let enumerator_di_nodes: SmallVec<Option<&'ll DIType>> = variants
-        .map(|(discr, variant_name)| {
-            unsafe {
-                Some(llvm::LLVMRustDIBuilderCreateEnumerator(
-                    DIB(cx),
-                    variant_name.as_ptr().cast(),
-                    variant_name.len(),
-                    // FIXME: what if enumeration has i128 discriminant?
-                    discr.val as i64,
-                    is_unsigned,
-                ))
-            }
+    let enumerator_di_nodes: SmallVec<Option<&'ll DIType>> = enumerators
+        .map(|(name, value)| unsafe {
+            let value = [value as u64, (value >> 64) as u64];
+            Some(llvm::LLVMRustDIBuilderCreateEnumerator(
+                DIB(cx),
+                name.as_ptr().cast(),
+                name.len(),
+                value.as_ptr(),
+                size.bits() as libc::c_uint,
+                is_unsigned,
+            ))
         })
         .collect();
 
-    let (size, align) = cx.size_and_align_of(base_type);
-
     unsafe {
         llvm::LLVMRustDIBuilderCreateEnumerationType(
             DIB(cx),
@@ -247,30 +242,34 @@ fn build_enumeration_type_di_node<'ll, 'tcx>(
 /// and a DW_TAG_member for each field (but not the discriminant).
 fn build_enum_variant_struct_type_di_node<'ll, 'tcx>(
     cx: &CodegenCx<'ll, 'tcx>,
-    enum_type: Ty<'tcx>,
+    enum_type_and_layout: TyAndLayout<'tcx>,
     enum_type_di_node: &'ll DIType,
     variant_index: VariantIdx,
     variant_def: &VariantDef,
     variant_layout: TyAndLayout<'tcx>,
 ) -> &'ll DIType {
-    debug_assert_eq!(variant_layout.ty, enum_type);
+    debug_assert_eq!(variant_layout.ty, enum_type_and_layout.ty);
 
     type_map::build_type_with_children(
         cx,
         type_map::stub(
             cx,
             Stub::Struct,
-            UniqueTypeId::for_enum_variant_struct_type(cx.tcx, enum_type, variant_index),
+            UniqueTypeId::for_enum_variant_struct_type(
+                cx.tcx,
+                enum_type_and_layout.ty,
+                variant_index,
+            ),
             variant_def.name.as_str(),
             // NOTE: We use size and align of enum_type, not from variant_layout:
-            cx.size_and_align_of(enum_type),
+            size_and_align_of(enum_type_and_layout),
             Some(enum_type_di_node),
             DIFlags::FlagZero,
         ),
         |cx, struct_type_di_node| {
             (0..variant_layout.fields.count())
                 .map(|field_index| {
-                    let field_name = if variant_def.ctor_kind != CtorKind::Fn {
+                    let field_name = if variant_def.ctor_kind() != Some(CtorKind::Fn) {
                         // Fields have names
                         Cow::from(variant_def.fields[field_index].name.as_str())
                     } else {
@@ -290,9 +289,9 @@ fn build_enum_variant_struct_type_di_node<'ll, 'tcx>(
                         type_di_node(cx, field_layout.ty),
                     )
                 })
-                .collect()
+                .collect::<SmallVec<_>>()
         },
-        |cx| build_generic_type_param_di_nodes(cx, enum_type),
+        |cx| build_generic_type_param_di_nodes(cx, enum_type_and_layout.ty),
     )
     .di_node
 }
@@ -398,39 +397,60 @@ pub fn build_generator_variant_struct_type_di_node<'ll, 'tcx>(
     .di_node
 }
 
+#[derive(Copy, Clone)]
+enum DiscrResult {
+    NoDiscriminant,
+    Value(u128),
+    Range(u128, u128),
+}
+
+impl DiscrResult {
+    fn opt_single_val(&self) -> Option<u128> {
+        if let Self::Value(d) = *self { Some(d) } else { None }
+    }
+}
+
 /// Returns the discriminant value corresponding to the variant index.
 ///
 /// Will return `None` if there is less than two variants (because then the enum won't have)
-/// a tag, and if this is the dataful variant of a niche-layout enum (because then there is no
+/// a tag, and if this is the untagged variant of a niche-layout enum (because then there is no
 /// single discriminant value).
 fn compute_discriminant_value<'ll, 'tcx>(
     cx: &CodegenCx<'ll, 'tcx>,
     enum_type_and_layout: TyAndLayout<'tcx>,
     variant_index: VariantIdx,
-) -> Option<u64> {
+) -> DiscrResult {
     match enum_type_and_layout.layout.variants() {
-        &Variants::Single { .. } => None,
-        &Variants::Multiple { tag_encoding: TagEncoding::Direct, .. } => Some(
-            enum_type_and_layout.ty.discriminant_for_variant(cx.tcx, variant_index).unwrap().val
-                as u64,
+        &Variants::Single { .. } => DiscrResult::NoDiscriminant,
+        &Variants::Multiple { tag_encoding: TagEncoding::Direct, .. } => DiscrResult::Value(
+            enum_type_and_layout.ty.discriminant_for_variant(cx.tcx, variant_index).unwrap().val,
         ),
         &Variants::Multiple {
-            tag_encoding: TagEncoding::Niche { ref niche_variants, niche_start, dataful_variant },
+            tag_encoding: TagEncoding::Niche { ref niche_variants, niche_start, untagged_variant },
             tag,
             ..
         } => {
-            if variant_index == dataful_variant {
-                None
+            if variant_index == untagged_variant {
+                let valid_range = enum_type_and_layout
+                    .for_variant(cx, variant_index)
+                    .largest_niche
+                    .as_ref()
+                    .unwrap()
+                    .valid_range;
+
+                let min = valid_range.start.min(valid_range.end);
+                let min = tag.size(cx).truncate(min);
+
+                let max = valid_range.start.max(valid_range.end);
+                let max = tag.size(cx).truncate(max);
+
+                DiscrResult::Range(min, max)
             } else {
                 let value = (variant_index.as_u32() as u128)
                     .wrapping_sub(niche_variants.start().as_u32() as u128)
                     .wrapping_add(niche_start);
                 let value = tag.size(cx).truncate(value);
-                // NOTE(eddyb) do *NOT* remove this assert, until
-                // we pass the full 128-bit value to LLVM, otherwise
-                // truncation will be silent and remain undetected.
-                assert_eq!(value as u64 as u128, value);
-                Some(value as u64)
+                DiscrResult::Value(value)
             }
         }
     }
diff --git a/compiler/rustc_codegen_llvm/src/debuginfo/metadata/enums/native.rs b/compiler/rustc_codegen_llvm/src/debuginfo/metadata/enums/native.rs
index f1935e0ec31..becbccc434d 100644
--- a/compiler/rustc_codegen_llvm/src/debuginfo/metadata/enums/native.rs
+++ b/compiler/rustc_codegen_llvm/src/debuginfo/metadata/enums/native.rs
@@ -88,7 +88,7 @@ pub(super) fn build_enum_type_di_node<'ll, 'tcx>(
                     variant_name: Cow::from(enum_adt_def.variant(variant_index).name.as_str()),
                     variant_struct_type_di_node: super::build_enum_variant_struct_type_di_node(
                         cx,
-                        enum_type,
+                        enum_type_and_layout,
                         enum_type_di_node,
                         variant_index,
                         enum_adt_def.variant(variant_index),
@@ -378,7 +378,7 @@ fn build_discr_member_di_node<'ll, 'tcx>(
 ///
 /// The DW_AT_discr_value is optional, and is omitted if
 ///   - This is the only variant of a univariant enum (i.e. their is no discriminant)
-///   - This is the "dataful" variant of a niche-layout enum
+///   - This is the "untagged" variant of a niche-layout enum
 ///     (where only the other variants are identified by a single value)
 ///
 /// There is only ever a single member, the type of which is a struct that describes the
@@ -413,7 +413,13 @@ fn build_enum_variant_member_di_node<'ll, 'tcx>(
             enum_type_and_layout.size.bits(),
             enum_type_and_layout.align.abi.bits() as u32,
             Size::ZERO.bits(),
-            discr_value.map(|v| cx.const_u64(v)),
+            discr_value.opt_single_val().map(|value| {
+                // NOTE(eddyb) do *NOT* remove this assert, until
+                // we pass the full 128-bit value to LLVM, otherwise
+                // truncation will be silent and remain undetected.
+                assert_eq!(value as u64 as u128, value);
+                cx.const_u64(value as u64)
+            }),
             DIFlags::FlagZero,
             variant_member_info.variant_struct_type_di_node,
         )
diff --git a/compiler/rustc_codegen_llvm/src/debuginfo/metadata/type_map.rs b/compiler/rustc_codegen_llvm/src/debuginfo/metadata/type_map.rs
index 87fbb737ea8..e30622cbdce 100644
--- a/compiler/rustc_codegen_llvm/src/debuginfo/metadata/type_map.rs
+++ b/compiler/rustc_codegen_llvm/src/debuginfo/metadata/type_map.rs
@@ -47,6 +47,8 @@ pub(super) enum UniqueTypeId<'tcx> {
     VariantPart(Ty<'tcx>, private::HiddenZst),
     /// The ID for the artificial struct type describing a single enum variant.
     VariantStructType(Ty<'tcx>, VariantIdx, private::HiddenZst),
+    /// The ID for the additional wrapper struct type describing an enum variant in CPP-like mode.
+    VariantStructTypeCppLikeWrapper(Ty<'tcx>, VariantIdx, private::HiddenZst),
     /// The ID of the artificial type we create for VTables.
     VTableTy(Ty<'tcx>, Option<PolyExistentialTraitRef<'tcx>>, private::HiddenZst),
 }
@@ -71,6 +73,15 @@ impl<'tcx> UniqueTypeId<'tcx> {
         UniqueTypeId::VariantStructType(enum_ty, variant_idx, private::HiddenZst)
     }
 
+    pub fn for_enum_variant_struct_type_wrapper(
+        tcx: TyCtxt<'tcx>,
+        enum_ty: Ty<'tcx>,
+        variant_idx: VariantIdx,
+    ) -> Self {
+        debug_assert_eq!(enum_ty, tcx.normalize_erasing_regions(ParamEnv::reveal_all(), enum_ty));
+        UniqueTypeId::VariantStructTypeCppLikeWrapper(enum_ty, variant_idx, private::HiddenZst)
+    }
+
     pub fn for_vtable_ty(
         tcx: TyCtxt<'tcx>,
         self_type: Ty<'tcx>,
@@ -93,8 +104,9 @@ impl<'tcx> UniqueTypeId<'tcx> {
     /// Right now this takes the form of a hex-encoded opaque hash value.
     pub fn generate_unique_id_string(self, tcx: TyCtxt<'tcx>) -> String {
         let mut hasher = StableHasher::new();
-        let mut hcx = tcx.create_stable_hashing_context();
-        hcx.while_hashing_spans(false, |hcx| self.hash_stable(hcx, &mut hasher));
+        tcx.with_stable_hashing_context(|mut hcx| {
+            hcx.while_hashing_spans(false, |hcx| self.hash_stable(hcx, &mut hasher))
+        });
         hasher.finish::<Fingerprint>().to_hex()
     }
 
@@ -145,7 +157,7 @@ impl<'ll> DINodeCreationResult<'ll> {
 pub enum Stub<'ll> {
     Struct,
     Union,
-    VtableTy { vtable_holder: &'ll DIType },
+    VTableTy { vtable_holder: &'ll DIType },
 }
 
 pub struct StubInfo<'ll, 'tcx> {
@@ -179,9 +191,9 @@ pub(super) fn stub<'ll, 'tcx>(
     let unique_type_id_str = unique_type_id.generate_unique_id_string(cx.tcx);
 
     let metadata = match kind {
-        Stub::Struct | Stub::VtableTy { .. } => {
+        Stub::Struct | Stub::VTableTy { .. } => {
             let vtable_holder = match kind {
-                Stub::VtableTy { vtable_holder } => Some(vtable_holder),
+                Stub::VTableTy { vtable_holder } => Some(vtable_holder),
                 _ => None,
             };
             unsafe {
diff --git a/compiler/rustc_codegen_llvm/src/debuginfo/mod.rs b/compiler/rustc_codegen_llvm/src/debuginfo/mod.rs
index 71699b5cf38..ca7a07d8391 100644
--- a/compiler/rustc_codegen_llvm/src/debuginfo/mod.rs
+++ b/compiler/rustc_codegen_llvm/src/debuginfo/mod.rs
@@ -27,7 +27,7 @@ use rustc_index::vec::IndexVec;
 use rustc_middle::mir;
 use rustc_middle::ty::layout::LayoutOf;
 use rustc_middle::ty::subst::{GenericArgKind, SubstsRef};
-use rustc_middle::ty::{self, Instance, ParamEnv, Ty, TypeFoldable};
+use rustc_middle::ty::{self, Instance, ParamEnv, Ty, TypeVisitable};
 use rustc_session::config::{self, DebugInfo};
 use rustc_session::Session;
 use rustc_span::symbol::Symbol;
@@ -39,7 +39,7 @@ use smallvec::SmallVec;
 use std::cell::OnceCell;
 use std::cell::RefCell;
 use std::iter;
-use tracing::debug;
+use std::ops::Range;
 
 mod create_scope_map;
 pub mod gdb;
@@ -97,23 +97,26 @@ impl<'ll, 'tcx> CodegenUnitDebugContext<'ll, 'tcx> {
         unsafe {
             llvm::LLVMRustDIBuilderFinalize(self.builder);
 
-            // Debuginfo generation in LLVM by default uses a higher
-            // version of dwarf than macOS currently understands. We can
-            // instruct LLVM to emit an older version of dwarf, however,
-            // for macOS to understand. For more info see #11352
-            // This can be overridden using --llvm-opts -dwarf-version,N.
-            // Android has the same issue (#22398)
-            if let Some(version) = sess.target.dwarf_version {
+            if !sess.target.is_like_msvc {
+                // Debuginfo generation in LLVM by default uses a higher
+                // version of dwarf than macOS currently understands. We can
+                // instruct LLVM to emit an older version of dwarf, however,
+                // for macOS to understand. For more info see #11352
+                // This can be overridden using --llvm-opts -dwarf-version,N.
+                // Android has the same issue (#22398)
+                let dwarf_version = sess
+                    .opts
+                    .unstable_opts
+                    .dwarf_version
+                    .unwrap_or(sess.target.default_dwarf_version);
                 llvm::LLVMRustAddModuleFlag(
                     self.llmod,
                     llvm::LLVMModFlagBehavior::Warning,
                     "Dwarf Version\0".as_ptr().cast(),
-                    version,
-                )
-            }
-
-            // Indicate that we want CodeView debug information on MSVC
-            if sess.target.is_like_msvc {
+                    dwarf_version,
+                );
+            } else {
+                // Indicate that we want CodeView debug information on MSVC
                 llvm::LLVMRustAddModuleFlag(
                     self.llmod,
                     llvm::LLVMModFlagBehavior::Warning,
@@ -161,12 +164,14 @@ impl<'ll> DebugInfoBuilderMethods for Builder<'_, 'll, '_> {
         variable_alloca: Self::Value,
         direct_offset: Size,
         indirect_offsets: &[Size],
+        fragment: Option<Range<Size>>,
     ) {
-        // Convert the direct and indirect offsets to address ops.
+        // Convert the direct and indirect offsets and fragment byte range to address ops.
         // FIXME(eddyb) use `const`s instead of getting the values via FFI,
         // the values should match the ones in the DWARF standard anyway.
         let op_deref = || unsafe { llvm::LLVMRustDIBuilderCreateOpDeref() };
         let op_plus_uconst = || unsafe { llvm::LLVMRustDIBuilderCreateOpPlusUconst() };
+        let op_llvm_fragment = || unsafe { llvm::LLVMRustDIBuilderCreateOpLLVMFragment() };
         let mut addr_ops = SmallVec::<[u64; 8]>::new();
 
         if direct_offset.bytes() > 0 {
@@ -180,6 +185,13 @@ impl<'ll> DebugInfoBuilderMethods for Builder<'_, 'll, '_> {
                 addr_ops.push(offset.bytes() as u64);
             }
         }
+        if let Some(fragment) = fragment {
+            // `DW_OP_LLVM_fragment` takes as arguments the fragment's
+            // offset and size, both of them in bits.
+            addr_ops.push(op_llvm_fragment());
+            addr_ops.push(fragment.start.bits() as u64);
+            addr_ops.push((fragment.end - fragment.start).bits() as u64);
+        }
 
         unsafe {
             // FIXME(eddyb) replace `llvm.dbg.declare` with `llvm.dbg.addr`.
diff --git a/compiler/rustc_codegen_llvm/src/debuginfo/utils.rs b/compiler/rustc_codegen_llvm/src/debuginfo/utils.rs
index 8f243673907..5cd0e1cb63a 100644
--- a/compiler/rustc_codegen_llvm/src/debuginfo/utils.rs
+++ b/compiler/rustc_codegen_llvm/src/debuginfo/utils.rs
@@ -6,7 +6,7 @@ use super::CodegenUnitDebugContext;
 use rustc_hir::def_id::DefId;
 use rustc_middle::ty::layout::{HasParamEnv, LayoutOf};
 use rustc_middle::ty::{self, DefIdTree, Ty};
-use tracing::trace;
+use trace;
 
 use crate::common::CodegenCx;
 use crate::llvm;
@@ -72,7 +72,7 @@ pub(crate) fn fat_pointer_kind<'ll, 'tcx>(
         layout.is_unsized()
     );
 
-    if !layout.is_unsized() {
+    if layout.is_sized() {
         return None;
     }
 
diff --git a/compiler/rustc_codegen_llvm/src/declare.rs b/compiler/rustc_codegen_llvm/src/declare.rs
index 5a5c4f7f860..dc21a02cec4 100644
--- a/compiler/rustc_codegen_llvm/src/declare.rs
+++ b/compiler/rustc_codegen_llvm/src/declare.rs
@@ -18,9 +18,10 @@ use crate::llvm;
 use crate::llvm::AttributePlace::Function;
 use crate::type_::Type;
 use crate::value::Value;
+use rustc_codegen_ssa::traits::TypeMembershipMethods;
 use rustc_middle::ty::Ty;
+use rustc_symbol_mangling::typeid::typeid_for_fnabi;
 use smallvec::SmallVec;
-use tracing::debug;
 
 /// Declare a function.
 ///
@@ -31,6 +32,7 @@ fn declare_raw_fn<'ll>(
     name: &str,
     callconv: llvm::CallConv,
     unnamed: llvm::UnnamedAddr,
+    visibility: llvm::Visibility,
     ty: &'ll Type,
 ) -> &'ll Value {
     debug!("declare_raw_fn(name={:?}, ty={:?})", name, ty);
@@ -40,6 +42,7 @@ fn declare_raw_fn<'ll>(
 
     llvm::SetFunctionCallConv(llfn, callconv);
     llvm::SetUnnamedAddress(llfn, unnamed);
+    llvm::set_visibility(llfn, visibility);
 
     let mut attrs = SmallVec::<[_; 4]>::new();
 
@@ -77,7 +80,36 @@ impl<'ll, 'tcx> CodegenCx<'ll, 'tcx> {
         unnamed: llvm::UnnamedAddr,
         fn_type: &'ll Type,
     ) -> &'ll Value {
-        declare_raw_fn(self, name, llvm::CCallConv, unnamed, fn_type)
+        // Declare C ABI functions with the visibility used by C by default.
+        let visibility = if self.tcx.sess.target.default_hidden_visibility {
+            llvm::Visibility::Hidden
+        } else {
+            llvm::Visibility::Default
+        };
+
+        declare_raw_fn(self, name, llvm::CCallConv, unnamed, visibility, fn_type)
+    }
+
+    /// Declare an entry Function
+    ///
+    /// The ABI of this function can change depending on the target (although for now the same as
+    /// `declare_cfn`)
+    ///
+    /// If there’s a value with the same name already declared, the function will
+    /// update the declaration and return existing Value instead.
+    pub fn declare_entry_fn(
+        &self,
+        name: &str,
+        callconv: llvm::CallConv,
+        unnamed: llvm::UnnamedAddr,
+        fn_type: &'ll Type,
+    ) -> &'ll Value {
+        let visibility = if self.tcx.sess.target.default_hidden_visibility {
+            llvm::Visibility::Hidden
+        } else {
+            llvm::Visibility::Default
+        };
+        declare_raw_fn(self, name, callconv, unnamed, visibility, fn_type)
     }
 
     /// Declare a Rust function.
@@ -94,9 +126,16 @@ impl<'ll, 'tcx> CodegenCx<'ll, 'tcx> {
             name,
             fn_abi.llvm_cconv(),
             llvm::UnnamedAddr::Global,
+            llvm::Visibility::Default,
             fn_abi.llvm_type(self),
         );
         fn_abi.apply_attrs_llfn(self, llfn);
+
+        if self.tcx.sess.is_sanitizer_cfi_enabled() {
+            let typeid = typeid_for_fnabi(self.tcx, fn_abi);
+            self.set_type_metadata(llfn, typeid);
+        }
+
         llfn
     }
 
diff --git a/compiler/rustc_codegen_llvm/src/errors.rs b/compiler/rustc_codegen_llvm/src/errors.rs
new file mode 100644
index 00000000000..af9f31fc324
--- /dev/null
+++ b/compiler/rustc_codegen_llvm/src/errors.rs
@@ -0,0 +1,120 @@
+use std::borrow::Cow;
+
+use rustc_errors::fluent;
+use rustc_errors::DiagnosticBuilder;
+use rustc_errors::ErrorGuaranteed;
+use rustc_errors::Handler;
+use rustc_errors::IntoDiagnostic;
+use rustc_macros::{Diagnostic, Subdiagnostic};
+use rustc_span::Span;
+
+#[derive(Diagnostic)]
+#[diag(codegen_llvm_unknown_ctarget_feature_prefix)]
+#[note]
+pub(crate) struct UnknownCTargetFeaturePrefix<'a> {
+    pub feature: &'a str,
+}
+
+#[derive(Diagnostic)]
+#[diag(codegen_llvm_unknown_ctarget_feature)]
+#[note]
+pub(crate) struct UnknownCTargetFeature<'a> {
+    pub feature: &'a str,
+    #[subdiagnostic]
+    pub rust_feature: PossibleFeature<'a>,
+}
+
+#[derive(Subdiagnostic)]
+pub(crate) enum PossibleFeature<'a> {
+    #[help(possible_feature)]
+    Some { rust_feature: &'a str },
+    #[help(consider_filing_feature_request)]
+    None,
+}
+
+#[derive(Diagnostic)]
+#[diag(codegen_llvm_error_creating_import_library)]
+pub(crate) struct ErrorCreatingImportLibrary<'a> {
+    pub lib_name: &'a str,
+    pub error: String,
+}
+
+#[derive(Diagnostic)]
+#[diag(codegen_llvm_instrument_coverage_requires_llvm_12)]
+pub(crate) struct InstrumentCoverageRequiresLLVM12;
+
+#[derive(Diagnostic)]
+#[diag(codegen_llvm_symbol_already_defined)]
+pub(crate) struct SymbolAlreadyDefined<'a> {
+    #[primary_span]
+    pub span: Span,
+    pub symbol_name: &'a str,
+}
+
+#[derive(Diagnostic)]
+#[diag(codegen_llvm_branch_protection_requires_aarch64)]
+pub(crate) struct BranchProtectionRequiresAArch64;
+
+#[derive(Diagnostic)]
+#[diag(codegen_llvm_invalid_minimum_alignment)]
+pub(crate) struct InvalidMinimumAlignment {
+    pub err: String,
+}
+
+#[derive(Diagnostic)]
+#[diag(codegen_llvm_sanitizer_memtag_requires_mte)]
+pub(crate) struct SanitizerMemtagRequiresMte;
+
+#[derive(Diagnostic)]
+#[diag(codegen_llvm_error_writing_def_file)]
+pub(crate) struct ErrorWritingDEFFile {
+    pub error: std::io::Error,
+}
+
+#[derive(Diagnostic)]
+#[diag(codegen_llvm_error_calling_dlltool)]
+pub(crate) struct ErrorCallingDllTool {
+    pub error: std::io::Error,
+}
+
+#[derive(Diagnostic)]
+#[diag(codegen_llvm_dlltool_fail_import_library)]
+pub(crate) struct DlltoolFailImportLibrary<'a> {
+    pub stdout: Cow<'a, str>,
+    pub stderr: Cow<'a, str>,
+}
+
+#[derive(Diagnostic)]
+#[diag(codegen_llvm_dynamic_linking_with_lto)]
+#[note]
+pub(crate) struct DynamicLinkingWithLTO;
+
+#[derive(Diagnostic)]
+#[diag(codegen_llvm_fail_parsing_target_machine_config_to_target_machine)]
+pub(crate) struct FailParsingTargetMachineConfigToTargetMachine {
+    pub error: String,
+}
+
+pub(crate) struct TargetFeatureDisableOrEnable<'a> {
+    pub features: &'a [&'a str],
+    pub span: Option<Span>,
+    pub missing_features: Option<MissingFeatures>,
+}
+
+#[derive(Subdiagnostic)]
+#[help(codegen_llvm_missing_features)]
+pub(crate) struct MissingFeatures;
+
+impl IntoDiagnostic<'_, ErrorGuaranteed> for TargetFeatureDisableOrEnable<'_> {
+    fn into_diagnostic(self, sess: &'_ Handler) -> DiagnosticBuilder<'_, ErrorGuaranteed> {
+        let mut diag = sess.struct_err(fluent::codegen_llvm_target_feature_disable_or_enable);
+        if let Some(span) = self.span {
+            diag.set_span(span);
+        };
+        if let Some(missing_features) = self.missing_features {
+            diag.subdiagnostic(missing_features);
+        }
+        diag.set_arg("features", self.features.join(", "));
+        diag
+    }
+}
diff --git a/compiler/rustc_codegen_llvm/src/intrinsic.rs b/compiler/rustc_codegen_llvm/src/intrinsic.rs
index a18f5b9dd7f..2f5dd519b26 100644
--- a/compiler/rustc_codegen_llvm/src/intrinsic.rs
+++ b/compiler/rustc_codegen_llvm/src/intrinsic.rs
@@ -71,6 +71,7 @@ fn get_simple_intrinsic<'ll>(
         sym::nearbyintf64 => "llvm.nearbyint.f64",
         sym::roundf32 => "llvm.round.f32",
         sym::roundf64 => "llvm.round.f64",
+        sym::ptr_mask => "llvm.ptrmask",
         _ => return None,
     };
     Some(cx.get_intrinsic(llvm_name))
@@ -107,6 +108,7 @@ impl<'ll, 'tcx> IntrinsicCallMethods<'tcx> for Builder<'_, 'll, 'tcx> {
                 let (simple_ty, simple_fn) = simple.unwrap();
                 self.call(
                     simple_ty,
+                    None,
                     simple_fn,
                     &args.iter().map(|arg| arg.immediate()).collect::<Vec<_>>(),
                     None,
@@ -161,7 +163,7 @@ impl<'ll, 'tcx> IntrinsicCallMethods<'tcx> for Builder<'_, 'll, 'tcx> {
             sym::volatile_load | sym::unaligned_volatile_load => {
                 let tp_ty = substs.type_at(0);
                 let ptr = args[0].immediate();
-                let load = if let PassMode::Cast(ty) = fn_abi.ret.mode {
+                let load = if let PassMode::Cast(ty, _) = &fn_abi.ret.mode {
                     let llty = ty.llvm_type(self);
                     let ptr = self.pointercast(ptr, self.type_ptr_to(llty));
                     self.volatile_load(llty, ptr)
@@ -338,17 +340,26 @@ impl<'ll, 'tcx> IntrinsicCallMethods<'tcx> for Builder<'_, 'll, 'tcx> {
 
             sym::black_box => {
                 args[0].val.store(self, result);
-
+                let result_val_span = [result.llval];
                 // We need to "use" the argument in some way LLVM can't introspect, and on
                 // targets that support it we can typically leverage inline assembly to do
                 // this. LLVM's interpretation of inline assembly is that it's, well, a black
                 // box. This isn't the greatest implementation since it probably deoptimizes
                 // more than we want, but it's so far good enough.
+                //
+                // For zero-sized types, the location pointed to by the result may be
+                // uninitialized. Do not "use" the result in this case; instead just clobber
+                // the memory.
+                let (constraint, inputs): (&str, &[_]) = if result.layout.is_zst() {
+                    ("~{memory}", &[])
+                } else {
+                    ("r,~{memory}", &result_val_span)
+                };
                 crate::asm::inline_asm_call(
                     self,
                     "",
-                    "r,~{memory}",
-                    &[result.llval],
+                    constraint,
+                    inputs,
                     self.type_void(),
                     true,
                     false,
@@ -374,7 +385,7 @@ impl<'ll, 'tcx> IntrinsicCallMethods<'tcx> for Builder<'_, 'll, 'tcx> {
         };
 
         if !fn_abi.ret.is_ignore() {
-            if let PassMode::Cast(ty) = fn_abi.ret.mode {
+            if let PassMode::Cast(ty, _) = &fn_abi.ret.mode {
                 let ptr_llty = self.type_ptr_to(ty.llvm_type(self));
                 let ptr = self.pointercast(result.llval, ptr_llty);
                 self.store(llval, ptr, result.align);
@@ -434,14 +445,14 @@ fn try_intrinsic<'ll>(
 ) {
     if bx.sess().panic_strategy() == PanicStrategy::Abort {
         let try_func_ty = bx.type_func(&[bx.type_i8p()], bx.type_void());
-        bx.call(try_func_ty, try_func, &[data], None);
+        bx.call(try_func_ty, None, try_func, &[data], None);
         // Return 0 unconditionally from the intrinsic call;
         // we can never unwind.
         let ret_align = bx.tcx().data_layout.i32_align.abi;
         bx.store(bx.const_i32(0), dest, ret_align);
     } else if wants_msvc_seh(bx.sess()) {
         codegen_msvc_try(bx, try_func, data, catch_func, dest);
-    } else if bx.sess().target.is_like_emscripten {
+    } else if bx.sess().target.os == "emscripten" {
         codegen_emcc_try(bx, try_func, data, catch_func, dest);
     } else {
         codegen_gnu_try(bx, try_func, data, catch_func, dest);
@@ -533,7 +544,7 @@ fn codegen_msvc_try<'ll>(
         let ptr_align = bx.tcx().data_layout.pointer_align.abi;
         let slot = bx.alloca(bx.type_i8p(), ptr_align);
         let try_func_ty = bx.type_func(&[bx.type_i8p()], bx.type_void());
-        bx.invoke(try_func_ty, try_func, &[data], normal, catchswitch, None);
+        bx.invoke(try_func_ty, None, try_func, &[data], normal, catchswitch, None);
 
         bx.switch_to_block(normal);
         bx.ret(bx.const_i32(0));
@@ -577,7 +588,7 @@ fn codegen_msvc_try<'ll>(
         let funclet = bx.catch_pad(cs, &[tydesc, flags, slot]);
         let ptr = bx.load(bx.type_i8p(), slot, ptr_align);
         let catch_ty = bx.type_func(&[bx.type_i8p(), bx.type_i8p()], bx.type_void());
-        bx.call(catch_ty, catch_func, &[data, ptr], Some(&funclet));
+        bx.call(catch_ty, None, catch_func, &[data, ptr], Some(&funclet));
         bx.catch_ret(&funclet, caught);
 
         // The flag value of 64 indicates a "catch-all".
@@ -585,7 +596,7 @@ fn codegen_msvc_try<'ll>(
         let flags = bx.const_i32(64);
         let null = bx.const_null(bx.type_i8p());
         let funclet = bx.catch_pad(cs, &[null, flags, null]);
-        bx.call(catch_ty, catch_func, &[data, null], Some(&funclet));
+        bx.call(catch_ty, None, catch_func, &[data, null], Some(&funclet));
         bx.catch_ret(&funclet, caught);
 
         bx.switch_to_block(caught);
@@ -594,7 +605,7 @@ fn codegen_msvc_try<'ll>(
 
     // Note that no invoke is used here because by definition this function
     // can't panic (that's what it's catching).
-    let ret = bx.call(llty, llfn, &[try_func, data, catch_func], None);
+    let ret = bx.call(llty, None, llfn, &[try_func, data, catch_func], None);
     let i32_align = bx.tcx().data_layout.i32_align.abi;
     bx.store(ret, dest, i32_align);
 }
@@ -637,7 +648,7 @@ fn codegen_gnu_try<'ll>(
         let data = llvm::get_param(bx.llfn(), 1);
         let catch_func = llvm::get_param(bx.llfn(), 2);
         let try_func_ty = bx.type_func(&[bx.type_i8p()], bx.type_void());
-        bx.invoke(try_func_ty, try_func, &[data], then, catch, None);
+        bx.invoke(try_func_ty, None, try_func, &[data], then, catch, None);
 
         bx.switch_to_block(then);
         bx.ret(bx.const_i32(0));
@@ -655,13 +666,13 @@ fn codegen_gnu_try<'ll>(
         bx.add_clause(vals, tydesc);
         let ptr = bx.extract_value(vals, 0);
         let catch_ty = bx.type_func(&[bx.type_i8p(), bx.type_i8p()], bx.type_void());
-        bx.call(catch_ty, catch_func, &[data, ptr], None);
+        bx.call(catch_ty, None, catch_func, &[data, ptr], None);
         bx.ret(bx.const_i32(1));
     });
 
     // Note that no invoke is used here because by definition this function
     // can't panic (that's what it's catching).
-    let ret = bx.call(llty, llfn, &[try_func, data, catch_func], None);
+    let ret = bx.call(llty, None, llfn, &[try_func, data, catch_func], None);
     let i32_align = bx.tcx().data_layout.i32_align.abi;
     bx.store(ret, dest, i32_align);
 }
@@ -701,7 +712,7 @@ fn codegen_emcc_try<'ll>(
         let data = llvm::get_param(bx.llfn(), 1);
         let catch_func = llvm::get_param(bx.llfn(), 2);
         let try_func_ty = bx.type_func(&[bx.type_i8p()], bx.type_void());
-        bx.invoke(try_func_ty, try_func, &[data], then, catch, None);
+        bx.invoke(try_func_ty, None, try_func, &[data], then, catch, None);
 
         bx.switch_to_block(then);
         bx.ret(bx.const_i32(0));
@@ -740,13 +751,13 @@ fn codegen_emcc_try<'ll>(
         let catch_data = bx.bitcast(catch_data, bx.type_i8p());
 
         let catch_ty = bx.type_func(&[bx.type_i8p(), bx.type_i8p()], bx.type_void());
-        bx.call(catch_ty, catch_func, &[data, catch_data], None);
+        bx.call(catch_ty, None, catch_func, &[data, catch_data], None);
         bx.ret(bx.const_i32(1));
     });
 
     // Note that no invoke is used here because by definition this function
     // can't panic (that's what it's catching).
-    let ret = bx.call(llty, llfn, &[try_func, data, catch_func], None);
+    let ret = bx.call(llty, None, llfn, &[try_func, data, catch_func], None);
     let i32_align = bx.tcx().data_layout.i32_align.abi;
     bx.store(ret, dest, i32_align);
 }
@@ -1216,8 +1227,13 @@ fn generic_simd_intrinsic<'ll, 'tcx>(
         };
         let llvm_name = &format!("llvm.{0}.v{1}{2}", intr_name, in_len, elem_ty_str);
         let f = bx.declare_cfn(llvm_name, llvm::UnnamedAddr::No, fn_ty);
-        let c =
-            bx.call(fn_ty, f, &args.iter().map(|arg| arg.immediate()).collect::<Vec<_>>(), None);
+        let c = bx.call(
+            fn_ty,
+            None,
+            f,
+            &args.iter().map(|arg| arg.immediate()).collect::<Vec<_>>(),
+            None,
+        );
         Ok(c)
     }
 
@@ -1416,8 +1432,13 @@ fn generic_simd_intrinsic<'ll, 'tcx>(
             llvm_elem_vec_ty,
         );
         let f = bx.declare_cfn(&llvm_intrinsic, llvm::UnnamedAddr::No, fn_ty);
-        let v =
-            bx.call(fn_ty, f, &[args[1].immediate(), alignment, mask, args[0].immediate()], None);
+        let v = bx.call(
+            fn_ty,
+            None,
+            f,
+            &[args[1].immediate(), alignment, mask, args[0].immediate()],
+            None,
+        );
         return Ok(v);
     }
 
@@ -1479,7 +1500,7 @@ fn generic_simd_intrinsic<'ll, 'tcx>(
         let (_, element_ty1) = arg_tys[1].simd_size_and_type(bx.tcx());
         let (_, element_ty2) = arg_tys[2].simd_size_and_type(bx.tcx());
         let (pointer_count, underlying_ty) = match element_ty1.kind() {
-            ty::RawPtr(p) if p.ty == in_elem && p.mutbl == hir::Mutability::Mut => {
+            ty::RawPtr(p) if p.ty == in_elem && p.mutbl.is_mut() => {
                 (ptr_count(element_ty1), non_ptr(element_ty1))
             }
             _ => {
@@ -1542,8 +1563,13 @@ fn generic_simd_intrinsic<'ll, 'tcx>(
         let fn_ty =
             bx.type_func(&[llvm_elem_vec_ty, llvm_pointer_vec_ty, alignment_ty, mask_ty], ret_t);
         let f = bx.declare_cfn(&llvm_intrinsic, llvm::UnnamedAddr::No, fn_ty);
-        let v =
-            bx.call(fn_ty, f, &[args[0].immediate(), args[1].immediate(), alignment, mask], None);
+        let v = bx.call(
+            fn_ty,
+            None,
+            f,
+            &[args[0].immediate(), args[1].immediate(), alignment, mask],
+            None,
+        );
         return Ok(v);
     }
 
@@ -1704,6 +1730,97 @@ unsupported {} from `{}` with element `{}` of size `{}` to `{}`"#,
     bitwise_red!(simd_reduce_all: vector_reduce_and, true);
     bitwise_red!(simd_reduce_any: vector_reduce_or, true);
 
+    if name == sym::simd_cast_ptr {
+        require_simd!(ret_ty, "return");
+        let (out_len, out_elem) = ret_ty.simd_size_and_type(bx.tcx());
+        require!(
+            in_len == out_len,
+            "expected return type with length {} (same as input type `{}`), \
+                  found `{}` with length {}",
+            in_len,
+            in_ty,
+            ret_ty,
+            out_len
+        );
+
+        match in_elem.kind() {
+            ty::RawPtr(p) => {
+                let (metadata, check_sized) = p.ty.ptr_metadata_ty(bx.tcx, |ty| {
+                    bx.tcx.normalize_erasing_regions(ty::ParamEnv::reveal_all(), ty)
+                });
+                assert!(!check_sized); // we are in codegen, so we shouldn't see these types
+                require!(metadata.is_unit(), "cannot cast fat pointer `{}`", in_elem)
+            }
+            _ => return_error!("expected pointer, got `{}`", in_elem),
+        }
+        match out_elem.kind() {
+            ty::RawPtr(p) => {
+                let (metadata, check_sized) = p.ty.ptr_metadata_ty(bx.tcx, |ty| {
+                    bx.tcx.normalize_erasing_regions(ty::ParamEnv::reveal_all(), ty)
+                });
+                assert!(!check_sized); // we are in codegen, so we shouldn't see these types
+                require!(metadata.is_unit(), "cannot cast to fat pointer `{}`", out_elem)
+            }
+            _ => return_error!("expected pointer, got `{}`", out_elem),
+        }
+
+        if in_elem == out_elem {
+            return Ok(args[0].immediate());
+        } else {
+            return Ok(bx.pointercast(args[0].immediate(), llret_ty));
+        }
+    }
+
+    if name == sym::simd_expose_addr {
+        require_simd!(ret_ty, "return");
+        let (out_len, out_elem) = ret_ty.simd_size_and_type(bx.tcx());
+        require!(
+            in_len == out_len,
+            "expected return type with length {} (same as input type `{}`), \
+                  found `{}` with length {}",
+            in_len,
+            in_ty,
+            ret_ty,
+            out_len
+        );
+
+        match in_elem.kind() {
+            ty::RawPtr(_) => {}
+            _ => return_error!("expected pointer, got `{}`", in_elem),
+        }
+        match out_elem.kind() {
+            ty::Uint(ty::UintTy::Usize) => {}
+            _ => return_error!("expected `usize`, got `{}`", out_elem),
+        }
+
+        return Ok(bx.ptrtoint(args[0].immediate(), llret_ty));
+    }
+
+    if name == sym::simd_from_exposed_addr {
+        require_simd!(ret_ty, "return");
+        let (out_len, out_elem) = ret_ty.simd_size_and_type(bx.tcx());
+        require!(
+            in_len == out_len,
+            "expected return type with length {} (same as input type `{}`), \
+                  found `{}` with length {}",
+            in_len,
+            in_ty,
+            ret_ty,
+            out_len
+        );
+
+        match in_elem.kind() {
+            ty::Uint(ty::UintTy::Usize) => {}
+            _ => return_error!("expected `usize`, got `{}`", in_elem),
+        }
+        match out_elem.kind() {
+            ty::RawPtr(_) => {}
+            _ => return_error!("expected pointer, got `{}`", out_elem),
+        }
+
+        return Ok(bx.inttoptr(args[0].immediate(), llret_ty));
+    }
+
     if name == sym::simd_cast || name == sym::simd_as {
         require_simd!(ret_ty, "return");
         let (out_len, out_elem) = ret_ty.simd_size_and_type(bx.tcx());
@@ -1900,7 +2017,7 @@ unsupported {} from `{}` with element `{}` of size `{}` to `{}`"#,
 
         let fn_ty = bx.type_func(&[vec_ty, vec_ty], vec_ty);
         let f = bx.declare_cfn(llvm_intrinsic, llvm::UnnamedAddr::No, fn_ty);
-        let v = bx.call(fn_ty, f, &[lhs, rhs], None);
+        let v = bx.call(fn_ty, None, f, &[lhs, rhs], None);
         return Ok(v);
     }
 
diff --git a/compiler/rustc_codegen_llvm/src/lib.rs b/compiler/rustc_codegen_llvm/src/lib.rs
index 6713a756735..246e82545c8 100644
--- a/compiler/rustc_codegen_llvm/src/lib.rs
+++ b/compiler/rustc_codegen_llvm/src/lib.rs
@@ -5,19 +5,24 @@
 //! This API is completely unstable and subject to change.
 
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
+#![feature(hash_raw_entry)]
 #![feature(let_chains)]
-#![feature(let_else)]
 #![feature(extern_types)]
 #![feature(once_cell)]
 #![feature(iter_intersperse)]
 #![recursion_limit = "256"]
 #![allow(rustc::potential_query_instability)]
+#![deny(rustc::untranslatable_diagnostic)]
+#![deny(rustc::diagnostic_outside_of_impl)]
 
 #[macro_use]
 extern crate rustc_macros;
+#[macro_use]
+extern crate tracing;
 
 use back::write::{create_informational_target_machine, create_target_machine};
 
+use errors::FailParsingTargetMachineConfigToTargetMachine;
 pub use llvm_util::target_features;
 use rustc_ast::expand::allocator::AllocatorKind;
 use rustc_codegen_ssa::back::lto::{LtoModuleCodegen, SerializedModule, ThinModule};
@@ -60,6 +65,7 @@ mod context;
 mod coverageinfo;
 mod debuginfo;
 mod declare;
+mod errors;
 mod intrinsic;
 
 // The following is a work around that replaces `pub mod llvm;` and that fixes issue 53912.
@@ -106,11 +112,11 @@ impl ExtraBackendMethods for LlvmCodegenBackend {
         tcx: TyCtxt<'tcx>,
         module_name: &str,
         kind: AllocatorKind,
-        has_alloc_error_handler: bool,
+        alloc_error_handler_kind: AllocatorKind,
     ) -> ModuleLlvm {
         let mut module_llvm = ModuleLlvm::new_metadata(tcx, module_name);
         unsafe {
-            allocator::codegen(tcx, &mut module_llvm, module_name, kind, has_alloc_error_handler);
+            allocator::codegen(tcx, &mut module_llvm, module_name, kind, alloc_error_handler_kind);
         }
         module_llvm
     }
@@ -129,12 +135,6 @@ impl ExtraBackendMethods for LlvmCodegenBackend {
     ) -> TargetMachineFactoryFn<Self> {
         back::write::target_machine_factory(sess, optlvl, target_features)
     }
-    fn target_cpu<'b>(&self, sess: &'b Session) -> &'b str {
-        llvm_util::target_cpu(sess)
-    }
-    fn tune_cpu<'b>(&self, sess: &'b Session) -> Option<&'b str> {
-        llvm_util::tune_cpu(sess)
-    }
 
     fn spawn_thread<F, T>(time_trace: bool, f: F) -> std::thread::JoinHandle<T>
     where
@@ -168,7 +168,6 @@ impl ExtraBackendMethods for LlvmCodegenBackend {
 impl WriteBackendMethods for LlvmCodegenBackend {
     type Module = ModuleLlvm;
     type ModuleBuffer = back::lto::ModuleBuffer;
-    type Context = llvm::Context;
     type TargetMachine = &'static mut llvm::TargetMachine;
     type ThinData = back::lto::ThinData;
     type ThinBuffer = back::lto::ThinBuffer;
@@ -323,8 +322,8 @@ impl CodegenBackend for LlvmCodegenBackend {
         llvm_util::print_version();
     }
 
-    fn target_features(&self, sess: &Session) -> Vec<Symbol> {
-        target_features(sess)
+    fn target_features(&self, sess: &Session, allow_unstable: bool) -> Vec<Symbol> {
+        target_features(sess, allow_unstable)
     }
 
     fn codegen_crate<'tcx>(
@@ -354,7 +353,7 @@ impl CodegenBackend for LlvmCodegenBackend {
             .join(sess);
 
         sess.time("llvm_dump_timing_file", || {
-            if sess.opts.debugging_opts.llvm_time_trace {
+            if sess.opts.unstable_opts.llvm_time_trace {
                 let file_name = outputs.with_extension("llvm_timings.json");
                 llvm_util::time_trace_profiler_finish(&file_name);
             }
@@ -369,12 +368,12 @@ impl CodegenBackend for LlvmCodegenBackend {
         codegen_results: CodegenResults,
         outputs: &OutputFilenames,
     ) -> Result<(), ErrorGuaranteed> {
-        use crate::back::archive::LlvmArchiveBuilder;
+        use crate::back::archive::LlvmArchiveBuilderBuilder;
         use rustc_codegen_ssa::back::link::link_binary;
 
         // Run the linker on any artifacts that resulted from the LLVM run.
         // This should produce either a finished executable or library.
-        link_binary::<LlvmArchiveBuilder<'_>>(sess, &codegen_results, outputs)
+        link_binary(sess, &LlvmArchiveBuilderBuilder, &codegen_results, outputs)
     }
 }
 
@@ -417,7 +416,7 @@ impl ModuleLlvm {
             let tm = match (cgcx.tm_factory)(tm_factory_config) {
                 Ok(m) => m,
                 Err(e) => {
-                    handler.struct_err(&e).emit();
+                    handler.emit_err(FailParsingTargetMachineConfigToTargetMachine { error: e });
                     return Err(FatalError);
                 }
             };
diff --git a/compiler/rustc_codegen_llvm/src/llvm/archive_ro.rs b/compiler/rustc_codegen_llvm/src/llvm/archive_ro.rs
index 64db4f7462d..7d948970223 100644
--- a/compiler/rustc_codegen_llvm/src/llvm/archive_ro.rs
+++ b/compiler/rustc_codegen_llvm/src/llvm/archive_ro.rs
@@ -83,17 +83,6 @@ impl<'a> Child<'a> {
             }
         }
     }
-
-    pub fn data(&self) -> &'a [u8] {
-        unsafe {
-            let mut data_len = 0;
-            let data_ptr = super::LLVMRustArchiveChildData(self.raw, &mut data_len);
-            if data_ptr.is_null() {
-                panic!("failed to read data from archive child");
-            }
-            slice::from_raw_parts(data_ptr as *const u8, data_len as usize)
-        }
-    }
 }
 
 impl<'a> Drop for Child<'a> {
diff --git a/compiler/rustc_codegen_llvm/src/llvm/diagnostic.rs b/compiler/rustc_codegen_llvm/src/llvm/diagnostic.rs
index e2fa5e488ed..45de284d22a 100644
--- a/compiler/rustc_codegen_llvm/src/llvm/diagnostic.rs
+++ b/compiler/rustc_codegen_llvm/src/llvm/diagnostic.rs
@@ -20,19 +20,6 @@ pub enum OptimizationDiagnosticKind {
     OptimizationRemarkOther,
 }
 
-impl OptimizationDiagnosticKind {
-    pub fn describe(self) -> &'static str {
-        match self {
-            OptimizationRemark | OptimizationRemarkOther => "remark",
-            OptimizationMissed => "missed",
-            OptimizationAnalysis => "analysis",
-            OptimizationAnalysisFPCommute => "floating-point",
-            OptimizationAnalysisAliasing => "aliasing",
-            OptimizationFailure => "failure",
-        }
-    }
-}
-
 pub struct OptimizationDiagnostic<'ll> {
     pub kind: OptimizationDiagnosticKind,
     pub pass_name: String,
diff --git a/compiler/rustc_codegen_llvm/src/llvm/ffi.rs b/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
index b831423994f..8a9392255b8 100644
--- a/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
+++ b/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
@@ -35,7 +35,7 @@ pub enum LLVMRustResult {
 pub struct LLVMRustCOFFShortExport {
     pub name: *const c_char,
     pub ordinal_present: bool,
-    // value of `ordinal` only important when `ordinal_present` is true
+    /// value of `ordinal` only important when `ordinal_present` is true
     pub ordinal: u16,
 }
 
@@ -183,7 +183,6 @@ pub enum AttributeKind {
     OptimizeNone = 24,
     ReturnsTwice = 25,
     ReadNone = 26,
-    InaccessibleMemOnly = 27,
     SanitizeHWAddress = 28,
     WillReturn = 29,
     StackProtectReq = 30,
@@ -191,6 +190,11 @@ pub enum AttributeKind {
     StackProtect = 32,
     NoUndef = 33,
     SanitizeMemTag = 34,
+    NoCfCheck = 35,
+    ShadowCallStack = 36,
+    AllocSize = 37,
+    AllocatedPointer = 38,
+    AllocAlign = 39,
 }
 
 /// LLVMIntPredicate
@@ -395,27 +399,6 @@ impl AtomicOrdering {
     }
 }
 
-/// LLVMRustSynchronizationScope
-#[derive(Copy, Clone)]
-#[repr(C)]
-pub enum SynchronizationScope {
-    SingleThread,
-    CrossThread,
-}
-
-impl SynchronizationScope {
-    pub fn from_generic(sc: rustc_codegen_ssa::common::SynchronizationScope) -> Self {
-        match sc {
-            rustc_codegen_ssa::common::SynchronizationScope::SingleThread => {
-                SynchronizationScope::SingleThread
-            }
-            rustc_codegen_ssa::common::SynchronizationScope::CrossThread => {
-                SynchronizationScope::CrossThread
-            }
-        }
-    }
-}
-
 /// LLVMRustFileType
 #[derive(Copy, Clone)]
 #[repr(C)]
@@ -567,16 +550,6 @@ pub enum ArchiveKind {
     K_COFF,
 }
 
-/// LLVMRustPassKind
-#[derive(Copy, Clone, PartialEq, Debug)]
-#[repr(C)]
-#[allow(dead_code)] // Variants constructed by C++.
-pub enum PassKind {
-    Other,
-    Function,
-    Module,
-}
-
 // LLVMRustThinLTOData
 extern "C" {
     pub type ThinLTOData;
@@ -587,10 +560,6 @@ extern "C" {
     pub type ThinLTOBuffer;
 }
 
-// LLVMRustModuleNameCallback
-pub type ThinLTOModuleNameCallback =
-    unsafe extern "C" fn(*mut c_void, *const c_char, *const c_char);
-
 /// LLVMRustThinLTOModule
 #[repr(C)]
 pub struct ThinLTOModule {
@@ -620,6 +589,15 @@ pub enum ChecksumKind {
     SHA256,
 }
 
+/// LLVMRustMemoryEffects
+#[derive(Copy, Clone)]
+#[repr(C)]
+pub enum MemoryEffects {
+    None,
+    ReadOnly,
+    InaccessibleMemOnly,
+}
+
 extern "C" {
     type Opaque;
 }
@@ -656,9 +634,6 @@ extern "C" {
 }
 #[repr(C)]
 pub struct Builder<'a>(InvariantOpaque<'a>);
-extern "C" {
-    pub type MemoryBuffer;
-}
 #[repr(C)]
 pub struct PassManager<'a>(InvariantOpaque<'a>);
 extern "C" {
@@ -984,6 +959,22 @@ pub mod debuginfo {
     }
 }
 
+use bitflags::bitflags;
+// These values **must** match with LLVMRustAllocKindFlags
+bitflags! {
+    #[repr(transparent)]
+    #[derive(Default)]
+    pub struct AllocKindFlags : u64 {
+        const Unknown = 0;
+        const Alloc = 1;
+        const Realloc = 1 << 1;
+        const Free = 1 << 2;
+        const Uninitialized = 1 << 3;
+        const Zeroed = 1 << 4;
+        const Aligned = 1 << 5;
+    }
+}
+
 extern "C" {
     pub type ModuleBuffer;
 }
@@ -992,6 +983,9 @@ pub type SelfProfileBeforePassCallback =
     unsafe extern "C" fn(*mut c_void, *const c_char, *const c_char);
 pub type SelfProfileAfterPassCallback = unsafe extern "C" fn(*mut c_void);
 
+pub type GetSymbolsCallback = unsafe extern "C" fn(*mut c_void, *const c_char) -> *mut c_void;
+pub type GetSymbolsErrorCallback = unsafe extern "C" fn(*const c_char) -> *mut c_void;
+
 extern "C" {
     pub fn LLVMRustInstallFatalErrorHandler();
     pub fn LLVMRustDisableSystemDialogsOnCrash();
@@ -1011,7 +1005,6 @@ extern "C" {
     pub fn LLVMSetDataLayout(M: &Module, Triple: *const c_char);
 
     /// See Module::setModuleInlineAsm.
-    pub fn LLVMSetModuleInlineAsm2(M: &Module, Asm: *const c_char, AsmLen: size_t);
     pub fn LLVMRustAppendModuleInlineAsm(M: &Module, Asm: *const c_char, AsmLen: size_t);
 
     /// See llvm::LLVMTypeKind::getTypeID.
@@ -1093,7 +1086,7 @@ extern "C" {
     pub fn LLVMConstInt(IntTy: &Type, N: c_ulonglong, SignExtend: Bool) -> &Value;
     pub fn LLVMConstIntOfArbitraryPrecision(IntTy: &Type, Wn: c_uint, Ws: *const u64) -> &Value;
     pub fn LLVMConstReal(RealTy: &Type, N: f64) -> &Value;
-    pub fn LLVMConstIntGetZExtValue(ConstantVal: &ConstantInt) -> c_ulonglong;
+    pub fn LLVMRustConstIntGetZExtValue(ConstantVal: &ConstantInt, Value: &mut u64) -> bool;
     pub fn LLVMRustConstInt128Get(
         ConstantVal: &ConstantInt,
         SExt: bool,
@@ -1134,11 +1127,7 @@ extern "C" {
     pub fn LLVMConstIntToPtr<'a>(ConstantVal: &'a Value, ToType: &'a Type) -> &'a Value;
     pub fn LLVMConstBitCast<'a>(ConstantVal: &'a Value, ToType: &'a Type) -> &'a Value;
     pub fn LLVMConstPointerCast<'a>(ConstantVal: &'a Value, ToType: &'a Type) -> &'a Value;
-    pub fn LLVMConstExtractValue(
-        AggConstant: &Value,
-        IdxList: *const c_uint,
-        NumIdx: c_uint,
-    ) -> &Value;
+    pub fn LLVMGetAggregateElement(ConstantVal: &Value, Idx: c_uint) -> Option<&Value>;
 
     // Operations on global variables, functions, and aliases (globals)
     pub fn LLVMIsDeclaration(Global: &Value) -> Bool;
@@ -1169,7 +1158,6 @@ extern "C" {
     pub fn LLVMGetInitializer(GlobalVar: &Value) -> Option<&Value>;
     pub fn LLVMSetInitializer<'a>(GlobalVar: &'a Value, ConstantVal: &'a Value);
     pub fn LLVMIsThreadLocal(GlobalVar: &Value) -> Bool;
-    pub fn LLVMSetThreadLocal(GlobalVar: &Value, IsThreadLocal: Bool);
     pub fn LLVMSetThreadLocalMode(GlobalVar: &Value, Mode: ThreadLocalMode);
     pub fn LLVMIsGlobalConstant(GlobalVar: &Value) -> Bool;
     pub fn LLVMSetGlobalConstant(GlobalVar: &Value, IsConstant: Bool);
@@ -1194,7 +1182,11 @@ extern "C" {
     pub fn LLVMRustCreateDereferenceableOrNullAttr(C: &Context, bytes: u64) -> &Attribute;
     pub fn LLVMRustCreateByValAttr<'a>(C: &'a Context, ty: &'a Type) -> &'a Attribute;
     pub fn LLVMRustCreateStructRetAttr<'a>(C: &'a Context, ty: &'a Type) -> &'a Attribute;
+    pub fn LLVMRustCreateElementTypeAttr<'a>(C: &'a Context, ty: &'a Type) -> &'a Attribute;
     pub fn LLVMRustCreateUWTableAttr(C: &Context, async_: bool) -> &Attribute;
+    pub fn LLVMRustCreateAllocSizeAttr(C: &Context, size_arg: u32) -> &Attribute;
+    pub fn LLVMRustCreateAllocKindAttr(C: &Context, size_arg: u64) -> &Attribute;
+    pub fn LLVMRustCreateMemoryEffectsAttr(C: &Context, effects: MemoryEffects) -> &Attribute;
 
     // Operations on functions
     pub fn LLVMRustGetOrInsertFunction<'a>(
@@ -1623,7 +1615,7 @@ extern "C" {
         B: &Builder<'a>,
         Val: &'a Value,
         DestTy: &'a Type,
-        IsSized: bool,
+        IsSigned: bool,
     ) -> &'a Value;
 
     // Comparisons
@@ -1781,16 +1773,18 @@ extern "C" {
         Order: AtomicOrdering,
     ) -> &'a Value;
 
-    pub fn LLVMRustBuildAtomicCmpXchg<'a>(
+    pub fn LLVMBuildAtomicCmpXchg<'a>(
         B: &Builder<'a>,
         LHS: &'a Value,
         CMP: &'a Value,
         RHS: &'a Value,
         Order: AtomicOrdering,
         FailureOrder: AtomicOrdering,
-        Weak: Bool,
+        SingleThreaded: Bool,
     ) -> &'a Value;
 
+    pub fn LLVMSetWeak(CmpXchgInst: &Value, IsWeak: Bool);
+
     pub fn LLVMBuildAtomicRMW<'a>(
         B: &Builder<'a>,
         Op: AtomicRmwBinOp,
@@ -1800,27 +1794,19 @@ extern "C" {
         SingleThreaded: Bool,
     ) -> &'a Value;
 
-    pub fn LLVMRustBuildAtomicFence(
-        B: &Builder<'_>,
+    pub fn LLVMBuildFence<'a>(
+        B: &Builder<'a>,
         Order: AtomicOrdering,
-        Scope: SynchronizationScope,
-    );
+        SingleThreaded: Bool,
+        Name: *const c_char,
+    ) -> &'a Value;
 
     /// Writes a module to the specified path. Returns 0 on success.
     pub fn LLVMWriteBitcodeToFile(M: &Module, Path: *const c_char) -> c_int;
 
-    /// Creates a pass manager.
+    /// Creates a legacy pass manager -- only used for final codegen.
     pub fn LLVMCreatePassManager<'a>() -> &'a mut PassManager<'a>;
 
-    /// Creates a function-by-function pass manager
-    pub fn LLVMCreateFunctionPassManagerForModule(M: &Module) -> &mut PassManager<'_>;
-
-    /// Disposes a pass manager.
-    pub fn LLVMDisposePassManager<'a>(PM: &'a mut PassManager<'a>);
-
-    /// Runs a pass manager on a module.
-    pub fn LLVMRunPassManager<'a>(PM: &PassManager<'a>, M: &'a Module) -> Bool;
-
     pub fn LLVMInitializePasses();
 
     pub fn LLVMTimeTraceProfilerInitialize();
@@ -1831,32 +1817,6 @@ extern "C" {
 
     pub fn LLVMAddAnalysisPasses<'a>(T: &'a TargetMachine, PM: &PassManager<'a>);
 
-    pub fn LLVMRustPassManagerBuilderCreate() -> &'static mut PassManagerBuilder;
-    pub fn LLVMRustPassManagerBuilderDispose(PMB: &'static mut PassManagerBuilder);
-    pub fn LLVMRustPassManagerBuilderUseInlinerWithThreshold(
-        PMB: &PassManagerBuilder,
-        threshold: c_uint,
-    );
-    pub fn LLVMRustPassManagerBuilderPopulateModulePassManager(
-        PMB: &PassManagerBuilder,
-        PM: &PassManager<'_>,
-    );
-
-    pub fn LLVMRustPassManagerBuilderPopulateFunctionPassManager(
-        PMB: &PassManagerBuilder,
-        PM: &PassManager<'_>,
-    );
-    pub fn LLVMRustPassManagerBuilderPopulateLTOPassManager(
-        PMB: &PassManagerBuilder,
-        PM: &PassManager<'_>,
-        Internalize: Bool,
-        RunInliner: Bool,
-    );
-    pub fn LLVMRustPassManagerBuilderPopulateThinLTOPassManager(
-        PMB: &PassManagerBuilder,
-        PM: &PassManager<'_>,
-    );
-
     pub fn LLVMGetHostCPUFeatures() -> *mut c_char;
 
     pub fn LLVMDisposeMessage(message: *mut c_char);
@@ -2078,6 +2038,19 @@ extern "C" {
         Ty: &'a DIType,
     ) -> &'a DIType;
 
+    pub fn LLVMRustDIBuilderCreateStaticMemberType<'a>(
+        Builder: &DIBuilder<'a>,
+        Scope: &'a DIDescriptor,
+        Name: *const c_char,
+        NameLen: size_t,
+        File: &'a DIFile,
+        LineNo: c_uint,
+        Ty: &'a DIType,
+        Flags: DIFlags,
+        val: Option<&'a Value>,
+        AlignInBits: u32,
+    ) -> &'a DIDerivedType;
+
     pub fn LLVMRustDIBuilderCreateLexicalBlock<'a>(
         Builder: &DIBuilder<'a>,
         Scope: &'a DIScope,
@@ -2157,7 +2130,8 @@ extern "C" {
         Builder: &DIBuilder<'a>,
         Name: *const c_char,
         NameLen: size_t,
-        Value: i64,
+        Value: *const u64,
+        SizeInBits: c_uint,
         IsUnsigned: bool,
     ) -> &'a DIEnumerator;
 
@@ -2240,6 +2214,7 @@ extern "C" {
     ) -> &'a DILocation;
     pub fn LLVMRustDIBuilderCreateOpDeref() -> u64;
     pub fn LLVMRustDIBuilderCreateOpPlusUconst() -> u64;
+    pub fn LLVMRustDIBuilderCreateOpLLVMFragment() -> u64;
 
     #[allow(improper_ctypes)]
     pub fn LLVMRustWriteTypeToString(Type: &Type, s: &RustString);
@@ -2248,23 +2223,6 @@ extern "C" {
 
     pub fn LLVMIsAConstantInt(value_ref: &Value) -> Option<&ConstantInt>;
 
-    pub fn LLVMRustPassKind(Pass: &Pass) -> PassKind;
-    pub fn LLVMRustFindAndCreatePass(Pass: *const c_char) -> Option<&'static mut Pass>;
-    pub fn LLVMRustCreateAddressSanitizerFunctionPass(Recover: bool) -> &'static mut Pass;
-    pub fn LLVMRustCreateModuleAddressSanitizerPass(Recover: bool) -> &'static mut Pass;
-    pub fn LLVMRustCreateMemorySanitizerPass(
-        TrackOrigins: c_int,
-        Recover: bool,
-    ) -> &'static mut Pass;
-    pub fn LLVMRustCreateThreadSanitizerPass() -> &'static mut Pass;
-    pub fn LLVMRustCreateHWAddressSanitizerPass(Recover: bool) -> &'static mut Pass;
-    pub fn LLVMRustAddPass(PM: &PassManager<'_>, Pass: &'static mut Pass);
-    pub fn LLVMRustAddLastExtensionPasses(
-        PMB: &PassManagerBuilder,
-        Passes: *const &'static mut Pass,
-        NumPasses: size_t,
-    );
-
     pub fn LLVMRustHasFeature(T: &TargetMachine, s: *const c_char) -> bool;
 
     pub fn LLVMRustPrintTargetCPUs(T: &TargetMachine);
@@ -2298,29 +2256,11 @@ extern "C" {
         SplitDwarfFile: *const c_char,
     ) -> Option<&'static mut TargetMachine>;
     pub fn LLVMRustDisposeTargetMachine(T: &'static mut TargetMachine);
-    pub fn LLVMRustAddBuilderLibraryInfo<'a>(
-        PMB: &'a PassManagerBuilder,
-        M: &'a Module,
-        DisableSimplifyLibCalls: bool,
-    );
-    pub fn LLVMRustConfigurePassManagerBuilder(
-        PMB: &PassManagerBuilder,
-        OptLevel: CodeGenOptLevel,
-        MergeFunctions: bool,
-        SLPVectorize: bool,
-        LoopVectorize: bool,
-        PrepareForThinLTO: bool,
-        PGOGenPath: *const c_char,
-        PGOUsePath: *const c_char,
-        PGOSampleUsePath: *const c_char,
-        SizeLevel: c_int,
-    );
     pub fn LLVMRustAddLibraryInfo<'a>(
         PM: &PassManager<'a>,
         M: &'a Module,
         DisableSimplifyLibCalls: bool,
     );
-    pub fn LLVMRustRunFunctionPassManager<'a>(PM: &PassManager<'a>, M: &'a Module);
     pub fn LLVMRustWriteOutputFile<'a>(
         T: &'a TargetMachine,
         PM: &PassManager<'a>,
@@ -2329,7 +2269,7 @@ extern "C" {
         DwoOutput: *const c_char,
         FileType: FileType,
     ) -> LLVMRustResult;
-    pub fn LLVMRustOptimizeWithNewPassManager<'a>(
+    pub fn LLVMRustOptimize<'a>(
         M: &'a Module,
         TM: &'a TargetMachine,
         OptLevel: PassBuilderOptLevel,
@@ -2347,6 +2287,7 @@ extern "C" {
         PGOGenPath: *const c_char,
         PGOUsePath: *const c_char,
         InstrumentCoverage: bool,
+        InstrProfileOutput: *const c_char,
         InstrumentGCOV: bool,
         PGOSampleUsePath: *const c_char,
         DebugInfoForProfiling: bool,
@@ -2365,9 +2306,7 @@ extern "C" {
     ) -> LLVMRustResult;
     pub fn LLVMRustSetLLVMOptions(Argc: c_int, Argv: *const *const c_char);
     pub fn LLVMRustPrintPasses();
-    pub fn LLVMRustGetInstructionCount(M: &Module) -> u32;
     pub fn LLVMRustSetNormalizedTarget(M: &Module, triple: *const c_char);
-    pub fn LLVMRustAddAlwaysInlinePass(P: &PassManagerBuilder, AddLifetimes: bool);
     pub fn LLVMRustRunRestrictionPass(M: &Module, syms: *const *const c_char, len: size_t);
 
     pub fn LLVMRustOpenArchive(path: *const c_char) -> Option<&'static mut Archive>;
@@ -2376,7 +2315,6 @@ extern "C" {
         AIR: &ArchiveIterator<'a>,
     ) -> Option<&'a mut ArchiveChild<'a>>;
     pub fn LLVMRustArchiveChildName(ACR: &ArchiveChild<'_>, size: &mut size_t) -> *const c_char;
-    pub fn LLVMRustArchiveChildData(ACR: &ArchiveChild<'_>, size: &mut size_t) -> *const c_char;
     pub fn LLVMRustArchiveChildFree<'a>(ACR: &'a mut ArchiveChild<'a>);
     pub fn LLVMRustArchiveIteratorFree<'a>(AIR: &'a mut ArchiveIterator<'a>);
     pub fn LLVMRustDestroyArchive(AR: &'static mut Archive);
@@ -2411,12 +2349,6 @@ extern "C" {
         cookie_out: &mut c_uint,
     ) -> &'a SMDiagnostic;
 
-    pub fn LLVMRustSetInlineAsmDiagnosticHandler(
-        C: &Context,
-        H: InlineAsmDiagHandlerTy,
-        CX: *mut c_void,
-    );
-
     #[allow(improper_ctypes)]
     pub fn LLVMRustUnpackSMDiagnostic(
         d: &SMDiagnostic,
@@ -2463,7 +2395,6 @@ extern "C" {
     pub fn LLVMRustPositionBuilderAtStart<'a>(B: &Builder<'a>, BB: &'a BasicBlock);
 
     pub fn LLVMRustSetComdat<'a>(M: &'a Module, V: &'a Value, Name: *const c_char, NameLen: size_t);
-    pub fn LLVMRustUnsetComdat(V: &Value);
     pub fn LLVMRustSetModulePICLevel(M: &Module);
     pub fn LLVMRustSetModulePIELevel(M: &Module);
     pub fn LLVMRustSetModuleCodeModel(M: &Module, Model: CodeModel);
@@ -2473,7 +2404,7 @@ extern "C" {
     pub fn LLVMRustModuleBufferFree(p: &'static mut ModuleBuffer);
     pub fn LLVMRustModuleCost(M: &Module) -> u64;
 
-    pub fn LLVMRustThinLTOBufferCreate(M: &Module) -> &'static mut ThinLTOBuffer;
+    pub fn LLVMRustThinLTOBufferCreate(M: &Module, is_thin: bool) -> &'static mut ThinLTOBuffer;
     pub fn LLVMRustThinLTOBufferFree(M: &'static mut ThinLTOBuffer);
     pub fn LLVMRustThinLTOBufferPtr(M: &ThinLTOBuffer) -> *const c_char;
     pub fn LLVMRustThinLTOBufferLen(M: &ThinLTOBuffer) -> size_t;
@@ -2495,11 +2426,6 @@ extern "C" {
         Module: &Module,
         Target: &TargetMachine,
     ) -> bool;
-    pub fn LLVMRustGetThinLTOModuleImports(
-        Data: *const ThinLTOData,
-        ModuleNameCallback: ThinLTOModuleNameCallback,
-        CallbackPayload: *mut c_void,
-    );
     pub fn LLVMRustFreeThinLTOData(Data: &'static mut ThinLTOData);
     pub fn LLVMRustParseBitcodeForLTO(
         Context: &Context,
@@ -2512,8 +2438,12 @@ extern "C" {
         len: usize,
         out_len: &mut usize,
     ) -> *const u8;
-    pub fn LLVMRustLTOGetDICompileUnit(M: &Module, CU1: &mut *mut c_void, CU2: &mut *mut c_void);
-    pub fn LLVMRustLTOPatchDICompileUnit(M: &Module, CU: *mut c_void);
+    pub fn LLVMRustThinLTOGetDICompileUnit(
+        M: &Module,
+        CU1: &mut *mut c_void,
+        CU2: &mut *mut c_void,
+    );
+    pub fn LLVMRustThinLTOPatchDICompileUnit(M: &Module, CU: *mut c_void);
 
     pub fn LLVMRustLinkerNew(M: &Module) -> &mut Linker<'_>;
     pub fn LLVMRustLinkerAdd(
@@ -2545,4 +2475,16 @@ extern "C" {
 
     #[allow(improper_ctypes)]
     pub fn LLVMRustGetMangledName(V: &Value, out: &RustString);
+
+    pub fn LLVMRustGetElementTypeArgIndex(CallSite: &Value) -> i32;
+
+    pub fn LLVMRustIsBitcode(ptr: *const u8, len: usize) -> bool;
+
+    pub fn LLVMRustGetSymbols(
+        buf_ptr: *const u8,
+        buf_len: usize,
+        state: *mut c_void,
+        callback: GetSymbolsCallback,
+        error_callback: GetSymbolsErrorCallback,
+    ) -> *mut c_void;
 }
diff --git a/compiler/rustc_codegen_llvm/src/llvm/mod.rs b/compiler/rustc_codegen_llvm/src/llvm/mod.rs
index 48fbc1de8ee..f820e752371 100644
--- a/compiler/rustc_codegen_llvm/src/llvm/mod.rs
+++ b/compiler/rustc_codegen_llvm/src/llvm/mod.rs
@@ -95,6 +95,14 @@ pub fn CreateUWTableAttr(llcx: &Context, async_: bool) -> &Attribute {
     unsafe { LLVMRustCreateUWTableAttr(llcx, async_) }
 }
 
+pub fn CreateAllocSizeAttr(llcx: &Context, size_arg: u32) -> &Attribute {
+    unsafe { LLVMRustCreateAllocSizeAttr(llcx, size_arg) }
+}
+
+pub fn CreateAllocKindAttr(llcx: &Context, kind_arg: AllocKindFlags) -> &Attribute {
+    unsafe { LLVMRustCreateAllocKindAttr(llcx, kind_arg.bits()) }
+}
+
 #[derive(Copy, Clone)]
 pub enum AttributePlace {
     ReturnValue,
@@ -158,12 +166,6 @@ pub fn SetUniqueComdat(llmod: &Module, val: &Value) {
     }
 }
 
-pub fn UnsetComdat(val: &Value) {
-    unsafe {
-        LLVMRustUnsetComdat(val);
-    }
-}
-
 pub fn SetUnnamedAddress(global: &Value, unnamed: UnnamedAddr) {
     unsafe {
         LLVMSetUnnamedAddress(global, unnamed);
@@ -183,6 +185,13 @@ impl AttributeKind {
     }
 }
 
+impl MemoryEffects {
+    /// Create an LLVM Attribute with these memory effects.
+    pub fn create_attr(self, llcx: &Context) -> &Attribute {
+        unsafe { LLVMRustCreateMemoryEffectsAttr(llcx, self) }
+    }
+}
+
 pub fn set_section(llglobal: &Value, section_name: &str) {
     let section_name_cstr = CString::new(section_name).expect("unexpected CString error");
     unsafe {
diff --git a/compiler/rustc_codegen_llvm/src/llvm_util.rs b/compiler/rustc_codegen_llvm/src/llvm_util.rs
index ce6c6e3215c..2fa602520dc 100644
--- a/compiler/rustc_codegen_llvm/src/llvm_util.rs
+++ b/compiler/rustc_codegen_llvm/src/llvm_util.rs
@@ -1,7 +1,10 @@
 use crate::back::write::create_informational_target_machine;
-use crate::{llvm, llvm_util};
+use crate::errors::{
+    PossibleFeature, TargetFeatureDisableOrEnable, UnknownCTargetFeature,
+    UnknownCTargetFeaturePrefix,
+};
+use crate::llvm;
 use libc::c_int;
-use libloading::Library;
 use rustc_codegen_ssa::target_features::{
     supported_target_features, tied_target_features, RUSTC_SPECIFIC_FEATURES,
 };
@@ -15,9 +18,7 @@ use rustc_span::symbol::Symbol;
 use rustc_target::spec::{MergeFunctions, PanicStrategy};
 use smallvec::{smallvec, SmallVec};
 use std::ffi::{CStr, CString};
-use tracing::debug;
 
-use std::mem;
 use std::path::Path;
 use std::ptr;
 use std::slice;
@@ -87,22 +88,12 @@ unsafe fn configure_llvm(sess: &Session) {
             add("-debug-pass=Structure", false);
         }
         if sess.target.generate_arange_section
-            && !sess.opts.debugging_opts.no_generate_arange_section
+            && !sess.opts.unstable_opts.no_generate_arange_section
         {
             add("-generate-arange-section", false);
         }
 
-        // Disable the machine outliner by default in LLVM versions 11 and LLVM
-        // version 12, where it leads to miscompilation.
-        //
-        // Ref:
-        // - https://github.com/rust-lang/rust/issues/85351
-        // - https://reviews.llvm.org/D103167
-        if llvm_util::get_version() < (13, 0, 0) {
-            add("-enable-machine-outliner=never", false);
-        }
-
-        match sess.opts.debugging_opts.merge_functions.unwrap_or(sess.target.merge_functions) {
+        match sess.opts.unstable_opts.merge_functions.unwrap_or(sess.target.merge_functions) {
             MergeFunctions::Disabled | MergeFunctions::Trampolines => {}
             MergeFunctions::Aliases => {
                 add("-mergefunc-use-aliases", false);
@@ -125,28 +116,12 @@ unsafe fn configure_llvm(sess: &Session) {
         }
     }
 
-    if sess.opts.debugging_opts.llvm_time_trace {
+    if sess.opts.unstable_opts.llvm_time_trace {
         llvm::LLVMTimeTraceProfilerInitialize();
     }
 
     llvm::LLVMInitializePasses();
 
-    // Use the legacy plugin registration if we don't use the new pass manager
-    if !should_use_new_llvm_pass_manager(
-        &sess.opts.debugging_opts.new_llvm_pass_manager,
-        &sess.target.arch,
-    ) {
-        // Register LLVM plugins by loading them into the compiler process.
-        for plugin in &sess.opts.debugging_opts.llvm_plugins {
-            let lib = Library::new(plugin).unwrap_or_else(|e| bug!("couldn't load plugin: {}", e));
-            debug!("LLVM plugin loaded successfully {:?} ({})", lib, plugin);
-
-            // Intentionally leak the dynamic library. We can't ever unload it
-            // since the library can make things that will live arbitrarily long.
-            mem::forget(lib);
-        }
-    }
-
     rustc_llvm::initialize_available_targets();
 
     llvm::LLVMRustSetLLVMOptions(llvm_args.len() as c_int, llvm_args.as_ptr());
@@ -165,6 +140,10 @@ pub fn time_trace_profiler_finish(file_name: &Path) {
 //
 // To find a list of LLVM's names, check llvm-project/llvm/include/llvm/Support/*TargetParser.def
 // where the * matches the architecture's name
+//
+// For targets not present in the above location, see llvm-project/llvm/lib/Target/{ARCH}/*.td
+// where `{ARCH}` is the architecture name. Look for instances of `SubtargetFeature`.
+//
 // Beware to not use the llvm github project for this, but check the git submodule
 // found in src/llvm-project
 // Though note that Rust can also be build with an external precompiled version of LLVM
@@ -184,6 +163,9 @@ pub fn to_llvm_features<'a>(sess: &Session, s: &'a str) -> SmallVec<[&'a str; 2]
         ("x86", "rdrand") => smallvec!["rdrnd"],
         ("x86", "bmi1") => smallvec!["bmi"],
         ("x86", "cmpxchg16b") => smallvec!["cx16"],
+        // FIXME: These aliases are misleading, and should be removed before avx512_target_feature is
+        // stabilized. They must remain until std::arch switches off them.
+        // rust#100752
         ("x86", "avx512vaes") => smallvec!["vaes"],
         ("x86", "avx512gfni") => smallvec!["gfni"],
         ("x86", "avx512vpclmulqdq") => smallvec!["vpclmulqdq"],
@@ -212,8 +194,8 @@ pub fn to_llvm_features<'a>(sess: &Session, s: &'a str) -> SmallVec<[&'a str; 2]
     }
 }
 
-// Given a map from target_features to whether they are enabled or disabled,
-// ensure only valid combinations are allowed.
+/// Given a map from target_features to whether they are enabled or disabled,
+/// ensure only valid combinations are allowed.
 pub fn check_tied_features(
     sess: &Session,
     features: &FxHashMap<&str, bool>,
@@ -231,28 +213,31 @@ pub fn check_tied_features(
     return None;
 }
 
-// Used to generate cfg variables and apply features
-// Must express features in the way Rust understands them
-pub fn target_features(sess: &Session) -> Vec<Symbol> {
+/// Used to generate cfg variables and apply features
+/// Must express features in the way Rust understands them
+pub fn target_features(sess: &Session, allow_unstable: bool) -> Vec<Symbol> {
     let target_machine = create_informational_target_machine(sess);
-    let mut features: Vec<Symbol> =
-        supported_target_features(sess)
-            .iter()
-            .filter_map(|&(feature, gate)| {
-                if sess.is_nightly_build() || gate.is_none() { Some(feature) } else { None }
-            })
-            .filter(|feature| {
-                // check that all features in a given smallvec are enabled
-                for llvm_feature in to_llvm_features(sess, feature) {
-                    let cstr = SmallCStr::new(llvm_feature);
-                    if !unsafe { llvm::LLVMRustHasFeature(target_machine, cstr.as_ptr()) } {
-                        return false;
-                    }
+    let mut features: Vec<Symbol> = supported_target_features(sess)
+        .iter()
+        .filter_map(|&(feature, gate)| {
+            if sess.is_nightly_build() || allow_unstable || gate.is_none() {
+                Some(feature)
+            } else {
+                None
+            }
+        })
+        .filter(|feature| {
+            // check that all features in a given smallvec are enabled
+            for llvm_feature in to_llvm_features(sess, feature) {
+                let cstr = SmallCStr::new(llvm_feature);
+                if !unsafe { llvm::LLVMRustHasFeature(target_machine, cstr.as_ptr()) } {
+                    return false;
                 }
-                true
-            })
-            .map(|feature| Symbol::intern(feature))
-            .collect();
+            }
+            true
+        })
+        .map(|feature| Symbol::intern(feature))
+        .collect();
 
     // LLVM 14 changed the ABI for i128 arguments to __float/__fix builtins on Win64
     // (see https://reviews.llvm.org/D110413). This unstable target feature is intended for use
@@ -307,30 +292,33 @@ fn llvm_target_features(tm: &llvm::TargetMachine) -> Vec<(&str, &str)> {
 }
 
 fn print_target_features(sess: &Session, tm: &llvm::TargetMachine) {
-    let mut target_features = llvm_target_features(tm);
+    let mut llvm_target_features = llvm_target_features(tm);
+    let mut known_llvm_target_features = FxHashSet::<&'static str>::default();
     let mut rustc_target_features = supported_target_features(sess)
         .iter()
-        .filter_map(|(feature, _gate)| {
-            for llvm_feature in to_llvm_features(sess, *feature) {
+        .map(|(feature, _gate)| {
+            let desc = if let Some(llvm_feature) = to_llvm_features(sess, *feature).first() {
                 // LLVM asserts that these are sorted. LLVM and Rust both use byte comparison for these strings.
-                match target_features.binary_search_by_key(&llvm_feature, |(f, _d)| f).ok().map(
-                    |index| {
-                        let (_f, desc) = target_features.remove(index);
-                        (*feature, desc)
-                    },
-                ) {
-                    Some(v) => return Some(v),
-                    None => {}
+                match llvm_target_features.binary_search_by_key(&llvm_feature, |(f, _d)| f).ok() {
+                    Some(index) => {
+                        known_llvm_target_features.insert(llvm_feature);
+                        llvm_target_features[index].1
+                    }
+                    None => "",
                 }
-            }
-            None
+            } else {
+                ""
+            };
+            (*feature, desc)
         })
         .collect::<Vec<_>>();
     rustc_target_features.extend_from_slice(&[(
         "crt-static",
         "Enables C Run-time Libraries to be statically linked",
     )]);
-    let max_feature_len = target_features
+    llvm_target_features.retain(|(f, _d)| !known_llvm_target_features.contains(f));
+
+    let max_feature_len = llvm_target_features
         .iter()
         .chain(rustc_target_features.iter())
         .map(|(feature, _desc)| feature.len())
@@ -342,10 +330,10 @@ fn print_target_features(sess: &Session, tm: &llvm::TargetMachine) {
         println!("    {1:0$} - {2}.", max_feature_len, feature, desc);
     }
     println!("\nCode-generation features supported by LLVM for this target:");
-    for (feature, desc) in &target_features {
+    for (feature, desc) in &llvm_target_features {
         println!("    {1:0$} - {2}.", max_feature_len, feature, desc);
     }
-    if target_features.is_empty() {
+    if llvm_target_features.is_empty() {
         println!("    Target features listing is not supported by this LLVM version.");
     }
     println!("\nUse +feature to enable a feature, or -feature to disable it.");
@@ -437,6 +425,8 @@ pub(crate) fn global_llvm_features(sess: &Session, diagnostics: bool) -> Vec<Str
             .features
             .split(',')
             .filter(|v| !v.is_empty() && backend_feature_name(v).is_some())
+            // Drop +atomics-32 feature introduced in LLVM 15.
+            .filter(|v| *v != "+atomics-32" || get_version() >= (15, 0, 0))
             .map(String::from),
     );
 
@@ -454,12 +444,7 @@ pub(crate) fn global_llvm_features(sess: &Session, diagnostics: bool) -> Vec<Str
                 Some(c @ '+' | c @ '-') => c,
                 Some(_) => {
                     if diagnostics {
-                        let mut diag = sess.struct_warn(&format!(
-                            "unknown feature specified for `-Ctarget-feature`: `{}`",
-                            s
-                        ));
-                        diag.note("features must begin with a `+` to enable or `-` to disable it");
-                        diag.emit();
+                        sess.emit_warning(UnknownCTargetFeaturePrefix { feature: s });
                     }
                     return None;
                 }
@@ -476,17 +461,15 @@ pub(crate) fn global_llvm_features(sess: &Session, diagnostics: bool) -> Vec<Str
                         None
                     }
                 });
-                let mut diag = sess.struct_warn(&format!(
-                    "unknown feature specified for `-Ctarget-feature`: `{}`",
-                    feature
-                ));
-                diag.note("it is still passed through to the codegen backend");
-                if let Some(rust_feature) = rust_feature {
-                    diag.help(&format!("you might have meant: `{}`", rust_feature));
+                let unknown_feature = if let Some(rust_feature) = rust_feature {
+                    UnknownCTargetFeature {
+                        feature,
+                        rust_feature: PossibleFeature::Some { rust_feature },
+                    }
                 } else {
-                    diag.note("consider filing a feature request");
-                }
-                diag.emit();
+                    UnknownCTargetFeature { feature, rust_feature: PossibleFeature::None }
+                };
+                sess.emit_warning(unknown_feature);
             }
 
             if diagnostics {
@@ -511,11 +494,17 @@ pub(crate) fn global_llvm_features(sess: &Session, diagnostics: bool) -> Vec<Str
         .flatten();
     features.extend(feats);
 
+    // FIXME: Move v8a to target definition list when earliest supported LLVM is 14.
+    if get_version() >= (14, 0, 0) && sess.target.arch == "aarch64" {
+        features.push("+v8a".into());
+    }
+
     if diagnostics && let Some(f) = check_tied_features(sess, &featsmap) {
-        sess.err(&format!(
-            "target features {} must all be enabled or disabled together",
-            f.join(", ")
-        ));
+        sess.emit_err(TargetFeatureDisableOrEnable {
+            features: f,
+            span: None,
+            missing_features: None,
+        });
     }
 
     features
@@ -538,22 +527,6 @@ fn backend_feature_name(s: &str) -> Option<&str> {
 }
 
 pub fn tune_cpu(sess: &Session) -> Option<&str> {
-    let name = sess.opts.debugging_opts.tune_cpu.as_ref()?;
+    let name = sess.opts.unstable_opts.tune_cpu.as_ref()?;
     Some(handle_native(name))
 }
-
-pub(crate) fn should_use_new_llvm_pass_manager(user_opt: &Option<bool>, target_arch: &str) -> bool {
-    // The new pass manager is enabled by default for LLVM >= 13.
-    // This matches Clang, which also enables it since Clang 13.
-
-    // Since LLVM 15, the legacy pass manager is no longer supported.
-    if llvm_util::get_version() >= (15, 0, 0) {
-        return true;
-    }
-
-    // There are some perf issues with the new pass manager when targeting
-    // s390x with LLVM 13, so enable the new pass manager only with LLVM 14.
-    // See https://github.com/rust-lang/rust/issues/89609.
-    let min_version = if target_arch == "s390x" { 14 } else { 13 };
-    user_opt.unwrap_or_else(|| llvm_util::get_version() >= (min_version, 0, 0))
-}
diff --git a/compiler/rustc_codegen_llvm/src/mono_item.rs b/compiler/rustc_codegen_llvm/src/mono_item.rs
index a3053742aad..76f692b2016 100644
--- a/compiler/rustc_codegen_llvm/src/mono_item.rs
+++ b/compiler/rustc_codegen_llvm/src/mono_item.rs
@@ -1,6 +1,7 @@
 use crate::attributes;
 use crate::base;
 use crate::context::CodegenCx;
+use crate::errors::SymbolAlreadyDefined;
 use crate::llvm;
 use crate::type_of::LayoutLlvmExt;
 use rustc_codegen_ssa::traits::*;
@@ -8,10 +9,9 @@ use rustc_hir::def_id::{DefId, LOCAL_CRATE};
 pub use rustc_middle::mir::mono::MonoItem;
 use rustc_middle::mir::mono::{Linkage, Visibility};
 use rustc_middle::ty::layout::{FnAbiOf, LayoutOf};
-use rustc_middle::ty::{self, Instance, TypeFoldable};
+use rustc_middle::ty::{self, Instance, TypeVisitable};
 use rustc_session::config::CrateType;
 use rustc_target::spec::RelocModel;
-use tracing::debug;
 
 impl<'tcx> PreDefineMethods<'tcx> for CodegenCx<'_, 'tcx> {
     fn predefine_static(
@@ -26,10 +26,8 @@ impl<'tcx> PreDefineMethods<'tcx> for CodegenCx<'_, 'tcx> {
         let llty = self.layout_of(ty).llvm_type(self);
 
         let g = self.define_global(symbol_name, llty).unwrap_or_else(|| {
-            self.sess().span_fatal(
-                self.tcx.def_span(def_id),
-                &format!("symbol `{}` is already defined", symbol_name),
-            )
+            self.sess()
+                .emit_fatal(SymbolAlreadyDefined { span: self.tcx.def_span(def_id), symbol_name })
         });
 
         unsafe {
diff --git a/compiler/rustc_codegen_llvm/src/type_.rs b/compiler/rustc_codegen_llvm/src/type_.rs
index cf2d3c423c3..5772b7e1d81 100644
--- a/compiler/rustc_codegen_llvm/src/type_.rs
+++ b/compiler/rustc_codegen_llvm/src/type_.rs
@@ -19,7 +19,7 @@ use rustc_target::abi::{AddressSpace, Align, Integer, Size};
 use std::fmt;
 use std::ptr;
 
-use libc::c_uint;
+use libc::{c_char, c_uint};
 
 impl PartialEq for Type {
     fn eq(&self, other: &Self) -> bool {
@@ -127,10 +127,6 @@ impl<'ll> CodegenCx<'ll, '_> {
     pub(crate) fn type_variadic_func(&self, args: &[&'ll Type], ret: &'ll Type) -> &'ll Type {
         unsafe { llvm::LLVMFunctionType(ret, args.as_ptr(), args.len() as c_uint, True) }
     }
-
-    pub(crate) fn type_array(&self, ty: &'ll Type, len: u64) -> &'ll Type {
-        unsafe { llvm::LLVMRustArrayType(ty, len) }
-    }
 }
 
 impl<'ll, 'tcx> BaseTypeMethods<'tcx> for CodegenCx<'ll, 'tcx> {
@@ -231,6 +227,10 @@ impl<'ll, 'tcx> BaseTypeMethods<'tcx> for CodegenCx<'ll, 'tcx> {
     fn val_ty(&self, v: &'ll Value) -> &'ll Type {
         common::val_ty(v)
     }
+
+    fn type_array(&self, ty: &'ll Type, len: u64) -> &'ll Type {
+        unsafe { llvm::LLVMRustArrayType(ty, len) }
+    }
 }
 
 impl Type {
@@ -238,7 +238,7 @@ impl Type {
         unsafe { llvm::LLVMInt8TypeInContext(llcx) }
     }
 
-    // Creates an integer type with the given number of bits, e.g., i24
+    /// Creates an integer type with the given number of bits, e.g., i24
     pub fn ix_llcx(llcx: &llvm::Context, num_bits: u64) -> &Type {
         unsafe { llvm::LLVMIntTypeInContext(llcx, num_bits as c_uint) }
     }
@@ -289,3 +289,31 @@ impl<'ll, 'tcx> LayoutTypeMethods<'tcx> for CodegenCx<'ll, 'tcx> {
         ty.llvm_type(self)
     }
 }
+
+impl<'ll, 'tcx> TypeMembershipMethods<'tcx> for CodegenCx<'ll, 'tcx> {
+    fn set_type_metadata(&self, function: &'ll Value, typeid: String) {
+        let typeid_metadata = self.typeid_metadata(typeid);
+        let v = [self.const_usize(0), typeid_metadata];
+        unsafe {
+            llvm::LLVMGlobalSetMetadata(
+                function,
+                llvm::MD_type as c_uint,
+                llvm::LLVMValueAsMetadata(llvm::LLVMMDNodeInContext(
+                    self.llcx,
+                    v.as_ptr(),
+                    v.len() as c_uint,
+                )),
+            )
+        }
+    }
+
+    fn typeid_metadata(&self, typeid: String) -> &'ll Value {
+        unsafe {
+            llvm::LLVMMDStringInContext(
+                self.llcx,
+                typeid.as_ptr() as *const c_char,
+                typeid.len() as c_uint,
+            )
+        }
+    }
+}
diff --git a/compiler/rustc_codegen_llvm/src/type_of.rs b/compiler/rustc_codegen_llvm/src/type_of.rs
index 86280523631..182adf81785 100644
--- a/compiler/rustc_codegen_llvm/src/type_of.rs
+++ b/compiler/rustc_codegen_llvm/src/type_of.rs
@@ -6,12 +6,11 @@ use rustc_codegen_ssa::traits::*;
 use rustc_middle::bug;
 use rustc_middle::ty::layout::{FnAbiOf, LayoutOf, TyAndLayout};
 use rustc_middle::ty::print::{with_no_trimmed_paths, with_no_visible_paths};
-use rustc_middle::ty::{self, Ty, TypeFoldable};
+use rustc_middle::ty::{self, Ty, TypeVisitable};
 use rustc_target::abi::{Abi, AddressSpace, Align, FieldsShape};
 use rustc_target::abi::{Int, Pointer, F32, F64};
 use rustc_target::abi::{PointeeInfo, Scalar, Size, TyAbiInterface, Variants};
 use smallvec::{smallvec, SmallVec};
-use tracing::debug;
 
 use std::fmt::Write;
 
@@ -141,7 +140,7 @@ fn struct_llfields<'a, 'tcx>(
         prev_effective_align = effective_field_align;
     }
     let padding_used = result.len() > field_count;
-    if !layout.is_unsized() && field_count > 0 {
+    if layout.is_sized() && field_count > 0 {
         if offset > layout.size {
             bug!("layout: {:#?} stride: {:?} offset: {:?}", layout, layout.size, offset);
         }