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-rw-r--r--compiler/rustc_codegen_llvm/src/context.rs1107
1 files changed, 1107 insertions, 0 deletions
diff --git a/compiler/rustc_codegen_llvm/src/context.rs b/compiler/rustc_codegen_llvm/src/context.rs
new file mode 100644
index 00000000000..7d92888feee
--- /dev/null
+++ b/compiler/rustc_codegen_llvm/src/context.rs
@@ -0,0 +1,1107 @@
+use crate::attributes;
+use crate::back::write::to_llvm_code_model;
+use crate::callee::get_fn;
+use crate::coverageinfo;
+use crate::debuginfo;
+use crate::llvm;
+use crate::llvm_util;
+use crate::type_::Type;
+use crate::value::Value;
+
+use rustc_codegen_ssa::base::{wants_msvc_seh, wants_wasm_eh};
+use rustc_codegen_ssa::errors as ssa_errors;
+use rustc_codegen_ssa::traits::*;
+use rustc_data_structures::base_n::ToBaseN;
+use rustc_data_structures::base_n::ALPHANUMERIC_ONLY;
+use rustc_data_structures::fx::FxHashMap;
+use rustc_data_structures::small_c_str::SmallCStr;
+use rustc_hir::def_id::DefId;
+use rustc_middle::mir::mono::CodegenUnit;
+use rustc_middle::ty::layout::{
+    FnAbiError, FnAbiOfHelpers, FnAbiRequest, HasParamEnv, LayoutError, LayoutOfHelpers,
+    TyAndLayout,
+};
+use rustc_middle::ty::{self, Instance, Ty, TyCtxt};
+use rustc_middle::{bug, span_bug};
+use rustc_session::config::{BranchProtection, CFGuard, CFProtection};
+use rustc_session::config::{CrateType, DebugInfo, PAuthKey, PacRet};
+use rustc_session::Session;
+use rustc_span::source_map::Spanned;
+use rustc_span::Span;
+use rustc_target::abi::{call::FnAbi, HasDataLayout, TargetDataLayout, VariantIdx};
+use rustc_target::spec::{HasTargetSpec, RelocModel, Target, TlsModel};
+use smallvec::SmallVec;
+
+use libc::c_uint;
+use std::borrow::Borrow;
+use std::cell::{Cell, RefCell};
+use std::ffi::CStr;
+use std::str;
+
+/// There is one `CodegenCx` per compilation unit. Each one has its own LLVM
+/// `llvm::Context` so that several compilation units may be optimized in parallel.
+/// All other LLVM data structures in the `CodegenCx` are tied to that `llvm::Context`.
+pub struct CodegenCx<'ll, 'tcx> {
+    pub tcx: TyCtxt<'tcx>,
+    pub check_overflow: bool,
+    pub use_dll_storage_attrs: bool,
+    pub tls_model: llvm::ThreadLocalMode,
+
+    pub llmod: &'ll llvm::Module,
+    pub llcx: &'ll llvm::Context,
+    pub codegen_unit: &'tcx CodegenUnit<'tcx>,
+
+    /// Cache instances of monomorphic and polymorphic items
+    pub instances: RefCell<FxHashMap<Instance<'tcx>, &'ll Value>>,
+    /// Cache generated vtables
+    pub vtables:
+        RefCell<FxHashMap<(Ty<'tcx>, Option<ty::PolyExistentialTraitRef<'tcx>>), &'ll Value>>,
+    /// Cache of constant strings,
+    pub const_str_cache: RefCell<FxHashMap<String, &'ll Value>>,
+
+    /// Cache of emitted const globals (value -> global)
+    pub const_globals: RefCell<FxHashMap<&'ll Value, &'ll Value>>,
+
+    /// List of globals for static variables which need to be passed to the
+    /// LLVM function ReplaceAllUsesWith (RAUW) when codegen is complete.
+    /// (We have to make sure we don't invalidate any Values referring
+    /// to constants.)
+    pub statics_to_rauw: RefCell<Vec<(&'ll Value, &'ll Value)>>,
+
+    /// Statics that will be placed in the llvm.used variable
+    /// See <https://llvm.org/docs/LangRef.html#the-llvm-used-global-variable> for details
+    pub used_statics: RefCell<Vec<&'ll Value>>,
+
+    /// Statics that will be placed in the llvm.compiler.used variable
+    /// See <https://llvm.org/docs/LangRef.html#the-llvm-compiler-used-global-variable> for details
+    pub compiler_used_statics: RefCell<Vec<&'ll Value>>,
+
+    /// Mapping of non-scalar types to llvm types.
+    pub type_lowering: RefCell<FxHashMap<(Ty<'tcx>, Option<VariantIdx>), &'ll Type>>,
+
+    /// Mapping of scalar types to llvm types.
+    pub scalar_lltypes: RefCell<FxHashMap<Ty<'tcx>, &'ll Type>>,
+
+    pub isize_ty: &'ll Type,
+
+    pub coverage_cx: Option<coverageinfo::CrateCoverageContext<'ll, 'tcx>>,
+    pub dbg_cx: Option<debuginfo::CodegenUnitDebugContext<'ll, 'tcx>>,
+
+    eh_personality: Cell<Option<&'ll Value>>,
+    eh_catch_typeinfo: Cell<Option<&'ll Value>>,
+    pub rust_try_fn: Cell<Option<(&'ll Type, &'ll Value)>>,
+
+    intrinsics: RefCell<FxHashMap<&'static str, (&'ll Type, &'ll Value)>>,
+
+    /// A counter that is used for generating local symbol names
+    local_gen_sym_counter: Cell<usize>,
+
+    /// `codegen_static` will sometimes create a second global variable with a
+    /// different type and clear the symbol name of the original global.
+    /// `global_asm!` needs to be able to find this new global so that it can
+    /// compute the correct mangled symbol name to insert into the asm.
+    pub renamed_statics: RefCell<FxHashMap<DefId, &'ll Value>>,
+}
+
+fn to_llvm_tls_model(tls_model: TlsModel) -> llvm::ThreadLocalMode {
+    match tls_model {
+        TlsModel::GeneralDynamic => llvm::ThreadLocalMode::GeneralDynamic,
+        TlsModel::LocalDynamic => llvm::ThreadLocalMode::LocalDynamic,
+        TlsModel::InitialExec => llvm::ThreadLocalMode::InitialExec,
+        TlsModel::LocalExec => llvm::ThreadLocalMode::LocalExec,
+        TlsModel::Emulated => llvm::ThreadLocalMode::GeneralDynamic,
+    }
+}
+
+pub unsafe fn create_module<'ll>(
+    tcx: TyCtxt<'_>,
+    llcx: &'ll llvm::Context,
+    mod_name: &str,
+) -> &'ll llvm::Module {
+    let sess = tcx.sess;
+    let mod_name = SmallCStr::new(mod_name);
+    let llmod = llvm::LLVMModuleCreateWithNameInContext(mod_name.as_ptr(), llcx);
+
+    let mut target_data_layout = sess.target.data_layout.to_string();
+    let llvm_version = llvm_util::get_version();
+    if llvm_version < (18, 0, 0) {
+        if sess.target.arch == "x86" || sess.target.arch == "x86_64" {
+            // LLVM 18 adjusts i128 to be 128-bit aligned on x86 variants.
+            // Earlier LLVMs leave this as default alignment, so remove it.
+            // See https://reviews.llvm.org/D86310
+            target_data_layout = target_data_layout.replace("-i128:128", "");
+        }
+    }
+
+    if llvm_version < (19, 0, 0) {
+        if sess.target.arch == "aarch64" || sess.target.arch.starts_with("arm64") {
+            // LLVM 19 sets -Fn32 in its data layout string for 64-bit ARM
+            // Earlier LLVMs leave this default, so remove it.
+            // See https://github.com/llvm/llvm-project/pull/90702
+            target_data_layout = target_data_layout.replace("-Fn32", "");
+        }
+    }
+
+    if llvm_version < (19, 0, 0) {
+        if sess.target.arch == "loongarch64" {
+            // LLVM 19 updates the LoongArch64 data layout.
+            // See https://github.com/llvm/llvm-project/pull/93814
+            target_data_layout = target_data_layout.replace("-n32:64", "-n64");
+        }
+    }
+
+    // Ensure the data-layout values hardcoded remain the defaults.
+    {
+        let tm = crate::back::write::create_informational_target_machine(tcx.sess);
+        llvm::LLVMRustSetDataLayoutFromTargetMachine(llmod, &tm);
+
+        let llvm_data_layout = llvm::LLVMGetDataLayoutStr(llmod);
+        let llvm_data_layout = str::from_utf8(CStr::from_ptr(llvm_data_layout).to_bytes())
+            .expect("got a non-UTF8 data-layout from LLVM");
+
+        if target_data_layout != llvm_data_layout {
+            tcx.dcx().emit_err(crate::errors::MismatchedDataLayout {
+                rustc_target: sess.opts.target_triple.to_string().as_str(),
+                rustc_layout: target_data_layout.as_str(),
+                llvm_target: sess.target.llvm_target.borrow(),
+                llvm_layout: llvm_data_layout,
+            });
+        }
+    }
+
+    let data_layout = SmallCStr::new(&target_data_layout);
+    llvm::LLVMSetDataLayout(llmod, data_layout.as_ptr());
+
+    let llvm_target = SmallCStr::new(&sess.target.llvm_target);
+    llvm::LLVMRustSetNormalizedTarget(llmod, llvm_target.as_ptr());
+
+    let reloc_model = sess.relocation_model();
+    if matches!(reloc_model, RelocModel::Pic | RelocModel::Pie) {
+        llvm::LLVMRustSetModulePICLevel(llmod);
+        // PIE is potentially more effective than PIC, but can only be used in executables.
+        // If all our outputs are executables, then we can relax PIC to PIE.
+        if reloc_model == RelocModel::Pie
+            || tcx.crate_types().iter().all(|ty| *ty == CrateType::Executable)
+        {
+            llvm::LLVMRustSetModulePIELevel(llmod);
+        }
+    }
+
+    // Linking object files with different code models is undefined behavior
+    // because the compiler would have to generate additional code (to span
+    // longer jumps) if a larger code model is used with a smaller one.
+    //
+    // See https://reviews.llvm.org/D52322 and https://reviews.llvm.org/D52323.
+    llvm::LLVMRustSetModuleCodeModel(llmod, to_llvm_code_model(sess.code_model()));
+
+    // If skipping the PLT is enabled, we need to add some module metadata
+    // to ensure intrinsic calls don't use it.
+    if !sess.needs_plt() {
+        let avoid_plt = c"RtLibUseGOT".as_ptr().cast();
+        llvm::LLVMRustAddModuleFlagU32(llmod, llvm::LLVMModFlagBehavior::Warning, avoid_plt, 1);
+    }
+
+    // Enable canonical jump tables if CFI is enabled. (See https://reviews.llvm.org/D65629.)
+    if sess.is_sanitizer_cfi_canonical_jump_tables_enabled() && sess.is_sanitizer_cfi_enabled() {
+        let canonical_jump_tables = c"CFI Canonical Jump Tables".as_ptr().cast();
+        llvm::LLVMRustAddModuleFlagU32(
+            llmod,
+            llvm::LLVMModFlagBehavior::Override,
+            canonical_jump_tables,
+            1,
+        );
+    }
+
+    // Enable LTO unit splitting if specified or if CFI is enabled. (See https://reviews.llvm.org/D53891.)
+    if sess.is_split_lto_unit_enabled() || sess.is_sanitizer_cfi_enabled() {
+        let enable_split_lto_unit = c"EnableSplitLTOUnit".as_ptr().cast();
+        llvm::LLVMRustAddModuleFlagU32(
+            llmod,
+            llvm::LLVMModFlagBehavior::Override,
+            enable_split_lto_unit,
+            1,
+        );
+    }
+
+    // Add "kcfi" module flag if KCFI is enabled. (See https://reviews.llvm.org/D119296.)
+    if sess.is_sanitizer_kcfi_enabled() {
+        let kcfi = c"kcfi".as_ptr().cast();
+        llvm::LLVMRustAddModuleFlagU32(llmod, llvm::LLVMModFlagBehavior::Override, kcfi, 1);
+    }
+
+    // Control Flow Guard is currently only supported by the MSVC linker on Windows.
+    if sess.target.is_like_msvc {
+        match sess.opts.cg.control_flow_guard {
+            CFGuard::Disabled => {}
+            CFGuard::NoChecks => {
+                // Set `cfguard=1` module flag to emit metadata only.
+                llvm::LLVMRustAddModuleFlagU32(
+                    llmod,
+                    llvm::LLVMModFlagBehavior::Warning,
+                    c"cfguard".as_ptr() as *const _,
+                    1,
+                )
+            }
+            CFGuard::Checks => {
+                // Set `cfguard=2` module flag to emit metadata and checks.
+                llvm::LLVMRustAddModuleFlagU32(
+                    llmod,
+                    llvm::LLVMModFlagBehavior::Warning,
+                    c"cfguard".as_ptr() as *const _,
+                    2,
+                )
+            }
+        }
+    }
+
+    if let Some(BranchProtection { bti, pac_ret }) = sess.opts.unstable_opts.branch_protection {
+        if sess.target.arch == "aarch64" {
+            llvm::LLVMRustAddModuleFlagU32(
+                llmod,
+                llvm::LLVMModFlagBehavior::Min,
+                c"branch-target-enforcement".as_ptr().cast(),
+                bti.into(),
+            );
+            llvm::LLVMRustAddModuleFlagU32(
+                llmod,
+                llvm::LLVMModFlagBehavior::Min,
+                c"sign-return-address".as_ptr().cast(),
+                pac_ret.is_some().into(),
+            );
+            let pac_opts = pac_ret.unwrap_or(PacRet { leaf: false, key: PAuthKey::A });
+            llvm::LLVMRustAddModuleFlagU32(
+                llmod,
+                llvm::LLVMModFlagBehavior::Min,
+                c"sign-return-address-all".as_ptr().cast(),
+                pac_opts.leaf.into(),
+            );
+            llvm::LLVMRustAddModuleFlagU32(
+                llmod,
+                llvm::LLVMModFlagBehavior::Min,
+                c"sign-return-address-with-bkey".as_ptr().cast(),
+                u32::from(pac_opts.key == PAuthKey::B),
+            );
+        } else {
+            bug!(
+                "branch-protection used on non-AArch64 target; \
+                  this should be checked in rustc_session."
+            );
+        }
+    }
+
+    // Pass on the control-flow protection flags to LLVM (equivalent to `-fcf-protection` in Clang).
+    if let CFProtection::Branch | CFProtection::Full = sess.opts.unstable_opts.cf_protection {
+        llvm::LLVMRustAddModuleFlagU32(
+            llmod,
+            llvm::LLVMModFlagBehavior::Override,
+            c"cf-protection-branch".as_ptr().cast(),
+            1,
+        )
+    }
+    if let CFProtection::Return | CFProtection::Full = sess.opts.unstable_opts.cf_protection {
+        llvm::LLVMRustAddModuleFlagU32(
+            llmod,
+            llvm::LLVMModFlagBehavior::Override,
+            c"cf-protection-return".as_ptr().cast(),
+            1,
+        )
+    }
+
+    if sess.opts.unstable_opts.virtual_function_elimination {
+        llvm::LLVMRustAddModuleFlagU32(
+            llmod,
+            llvm::LLVMModFlagBehavior::Error,
+            c"Virtual Function Elim".as_ptr().cast(),
+            1,
+        );
+    }
+
+    // Set module flag to enable Windows EHCont Guard (/guard:ehcont).
+    if sess.opts.unstable_opts.ehcont_guard {
+        llvm::LLVMRustAddModuleFlagU32(
+            llmod,
+            llvm::LLVMModFlagBehavior::Warning,
+            c"ehcontguard".as_ptr() as *const _,
+            1,
+        )
+    }
+
+    // Insert `llvm.ident` metadata.
+    //
+    // On the wasm targets it will get hooked up to the "producer" sections
+    // `processed-by` information.
+    #[allow(clippy::option_env_unwrap)]
+    let rustc_producer =
+        format!("rustc version {}", option_env!("CFG_VERSION").expect("CFG_VERSION"));
+    let name_metadata = llvm::LLVMMDStringInContext(
+        llcx,
+        rustc_producer.as_ptr().cast(),
+        rustc_producer.as_bytes().len() as c_uint,
+    );
+    llvm::LLVMAddNamedMetadataOperand(
+        llmod,
+        c"llvm.ident".as_ptr(),
+        llvm::LLVMMDNodeInContext(llcx, &name_metadata, 1),
+    );
+
+    // Emit RISC-V specific target-abi metadata
+    // to workaround lld as the LTO plugin not
+    // correctly setting target-abi for the LTO object
+    // FIXME: https://github.com/llvm/llvm-project/issues/50591
+    // If llvm_abiname is empty, emit nothing.
+    let llvm_abiname = &sess.target.options.llvm_abiname;
+    if matches!(sess.target.arch.as_ref(), "riscv32" | "riscv64") && !llvm_abiname.is_empty() {
+        llvm::LLVMRustAddModuleFlagString(
+            llmod,
+            llvm::LLVMModFlagBehavior::Error,
+            c"target-abi".as_ptr(),
+            llvm_abiname.as_ptr().cast(),
+            llvm_abiname.len(),
+        );
+    }
+
+    // Add module flags specified via -Z llvm_module_flag
+    for (key, value, behavior) in &sess.opts.unstable_opts.llvm_module_flag {
+        let key = format!("{key}\0");
+        let behavior = match behavior.as_str() {
+            "error" => llvm::LLVMModFlagBehavior::Error,
+            "warning" => llvm::LLVMModFlagBehavior::Warning,
+            "require" => llvm::LLVMModFlagBehavior::Require,
+            "override" => llvm::LLVMModFlagBehavior::Override,
+            "append" => llvm::LLVMModFlagBehavior::Append,
+            "appendunique" => llvm::LLVMModFlagBehavior::AppendUnique,
+            "max" => llvm::LLVMModFlagBehavior::Max,
+            "min" => llvm::LLVMModFlagBehavior::Min,
+            // We already checked this during option parsing
+            _ => unreachable!(),
+        };
+        llvm::LLVMRustAddModuleFlagU32(llmod, behavior, key.as_ptr().cast(), *value)
+    }
+
+    llmod
+}
+
+impl<'ll, 'tcx> CodegenCx<'ll, 'tcx> {
+    pub(crate) fn new(
+        tcx: TyCtxt<'tcx>,
+        codegen_unit: &'tcx CodegenUnit<'tcx>,
+        llvm_module: &'ll crate::ModuleLlvm,
+    ) -> Self {
+        // An interesting part of Windows which MSVC forces our hand on (and
+        // apparently MinGW didn't) is the usage of `dllimport` and `dllexport`
+        // attributes in LLVM IR as well as native dependencies (in C these
+        // correspond to `__declspec(dllimport)`).
+        //
+        // LD (BFD) in MinGW mode can often correctly guess `dllexport` but
+        // relying on that can result in issues like #50176.
+        // LLD won't support that and expects symbols with proper attributes.
+        // Because of that we make MinGW target emit dllexport just like MSVC.
+        // When it comes to dllimport we use it for constants but for functions
+        // rely on the linker to do the right thing. Opposed to dllexport this
+        // task is easy for them (both LD and LLD) and allows us to easily use
+        // symbols from static libraries in shared libraries.
+        //
+        // Whenever a dynamic library is built on Windows it must have its public
+        // interface specified by functions tagged with `dllexport` or otherwise
+        // they're not available to be linked against. This poses a few problems
+        // for the compiler, some of which are somewhat fundamental, but we use
+        // the `use_dll_storage_attrs` variable below to attach the `dllexport`
+        // attribute to all LLVM functions that are exported e.g., they're
+        // already tagged with external linkage). This is suboptimal for a few
+        // reasons:
+        //
+        // * If an object file will never be included in a dynamic library,
+        //   there's no need to attach the dllexport attribute. Most object
+        //   files in Rust are not destined to become part of a dll as binaries
+        //   are statically linked by default.
+        // * If the compiler is emitting both an rlib and a dylib, the same
+        //   source object file is currently used but with MSVC this may be less
+        //   feasible. The compiler may be able to get around this, but it may
+        //   involve some invasive changes to deal with this.
+        //
+        // The flip side of this situation is that whenever you link to a dll and
+        // you import a function from it, the import should be tagged with
+        // `dllimport`. At this time, however, the compiler does not emit
+        // `dllimport` for any declarations other than constants (where it is
+        // required), which is again suboptimal for even more reasons!
+        //
+        // * Calling a function imported from another dll without using
+        //   `dllimport` causes the linker/compiler to have extra overhead (one
+        //   `jmp` instruction on x86) when calling the function.
+        // * The same object file may be used in different circumstances, so a
+        //   function may be imported from a dll if the object is linked into a
+        //   dll, but it may be just linked against if linked into an rlib.
+        // * The compiler has no knowledge about whether native functions should
+        //   be tagged dllimport or not.
+        //
+        // For now the compiler takes the perf hit (I do not have any numbers to
+        // this effect) by marking very little as `dllimport` and praying the
+        // linker will take care of everything. Fixing this problem will likely
+        // require adding a few attributes to Rust itself (feature gated at the
+        // start) and then strongly recommending static linkage on Windows!
+        let use_dll_storage_attrs = tcx.sess.target.is_like_windows;
+
+        let check_overflow = tcx.sess.overflow_checks();
+
+        let tls_model = to_llvm_tls_model(tcx.sess.tls_model());
+
+        let (llcx, llmod) = (&*llvm_module.llcx, llvm_module.llmod());
+
+        let coverage_cx =
+            tcx.sess.instrument_coverage().then(coverageinfo::CrateCoverageContext::new);
+
+        let dbg_cx = if tcx.sess.opts.debuginfo != DebugInfo::None {
+            let dctx = debuginfo::CodegenUnitDebugContext::new(llmod);
+            debuginfo::metadata::build_compile_unit_di_node(
+                tcx,
+                codegen_unit.name().as_str(),
+                &dctx,
+            );
+            Some(dctx)
+        } else {
+            None
+        };
+
+        let isize_ty = Type::ix_llcx(llcx, tcx.data_layout.pointer_size.bits());
+
+        CodegenCx {
+            tcx,
+            check_overflow,
+            use_dll_storage_attrs,
+            tls_model,
+            llmod,
+            llcx,
+            codegen_unit,
+            instances: Default::default(),
+            vtables: Default::default(),
+            const_str_cache: Default::default(),
+            const_globals: Default::default(),
+            statics_to_rauw: RefCell::new(Vec::new()),
+            used_statics: RefCell::new(Vec::new()),
+            compiler_used_statics: RefCell::new(Vec::new()),
+            type_lowering: Default::default(),
+            scalar_lltypes: Default::default(),
+            isize_ty,
+            coverage_cx,
+            dbg_cx,
+            eh_personality: Cell::new(None),
+            eh_catch_typeinfo: Cell::new(None),
+            rust_try_fn: Cell::new(None),
+            intrinsics: Default::default(),
+            local_gen_sym_counter: Cell::new(0),
+            renamed_statics: Default::default(),
+        }
+    }
+
+    pub(crate) fn statics_to_rauw(&self) -> &RefCell<Vec<(&'ll Value, &'ll Value)>> {
+        &self.statics_to_rauw
+    }
+
+    #[inline]
+    pub fn coverage_context(&self) -> Option<&coverageinfo::CrateCoverageContext<'ll, 'tcx>> {
+        self.coverage_cx.as_ref()
+    }
+
+    pub(crate) fn create_used_variable_impl(&self, name: &'static CStr, values: &[&'ll Value]) {
+        let array = self.const_array(self.type_ptr(), values);
+
+        unsafe {
+            let g = llvm::LLVMAddGlobal(self.llmod, self.val_ty(array), name.as_ptr());
+            llvm::LLVMSetInitializer(g, array);
+            llvm::LLVMRustSetLinkage(g, llvm::Linkage::AppendingLinkage);
+            llvm::LLVMSetSection(g, c"llvm.metadata".as_ptr());
+        }
+    }
+}
+
+impl<'ll, 'tcx> MiscMethods<'tcx> for CodegenCx<'ll, 'tcx> {
+    fn vtables(
+        &self,
+    ) -> &RefCell<FxHashMap<(Ty<'tcx>, Option<ty::PolyExistentialTraitRef<'tcx>>), &'ll Value>>
+    {
+        &self.vtables
+    }
+
+    fn get_fn(&self, instance: Instance<'tcx>) -> &'ll Value {
+        get_fn(self, instance)
+    }
+
+    fn get_fn_addr(&self, instance: Instance<'tcx>) -> &'ll Value {
+        get_fn(self, instance)
+    }
+
+    fn eh_personality(&self) -> &'ll Value {
+        // The exception handling personality function.
+        //
+        // If our compilation unit has the `eh_personality` lang item somewhere
+        // within it, then we just need to codegen that. Otherwise, we're
+        // building an rlib which will depend on some upstream implementation of
+        // this function, so we just codegen a generic reference to it. We don't
+        // specify any of the types for the function, we just make it a symbol
+        // that LLVM can later use.
+        //
+        // Note that MSVC is a little special here in that we don't use the
+        // `eh_personality` lang item at all. Currently LLVM has support for
+        // both Dwarf and SEH unwind mechanisms for MSVC targets and uses the
+        // *name of the personality function* to decide what kind of unwind side
+        // tables/landing pads to emit. It looks like Dwarf is used by default,
+        // injecting a dependency on the `_Unwind_Resume` symbol for resuming
+        // an "exception", but for MSVC we want to force SEH. This means that we
+        // can't actually have the personality function be our standard
+        // `rust_eh_personality` function, but rather we wired it up to the
+        // CRT's custom personality function, which forces LLVM to consider
+        // landing pads as "landing pads for SEH".
+        if let Some(llpersonality) = self.eh_personality.get() {
+            return llpersonality;
+        }
+
+        let name = if wants_msvc_seh(self.sess()) {
+            Some("__CxxFrameHandler3")
+        } else if wants_wasm_eh(self.sess()) {
+            // LLVM specifically tests for the name of the personality function
+            // There is no need for this function to exist anywhere, it will
+            // not be called. However, its name has to be "__gxx_wasm_personality_v0"
+            // for native wasm exceptions.
+            Some("__gxx_wasm_personality_v0")
+        } else {
+            None
+        };
+
+        let tcx = self.tcx;
+        let llfn = match tcx.lang_items().eh_personality() {
+            Some(def_id) if name.is_none() => self.get_fn_addr(ty::Instance::expect_resolve(
+                tcx,
+                ty::ParamEnv::reveal_all(),
+                def_id,
+                ty::List::empty(),
+            )),
+            _ => {
+                let name = name.unwrap_or("rust_eh_personality");
+                if let Some(llfn) = self.get_declared_value(name) {
+                    llfn
+                } else {
+                    let fty = self.type_variadic_func(&[], self.type_i32());
+                    let llfn = self.declare_cfn(name, llvm::UnnamedAddr::Global, fty);
+                    let target_cpu = attributes::target_cpu_attr(self);
+                    attributes::apply_to_llfn(llfn, llvm::AttributePlace::Function, &[target_cpu]);
+                    llfn
+                }
+            }
+        };
+        self.eh_personality.set(Some(llfn));
+        llfn
+    }
+
+    fn sess(&self) -> &Session {
+        self.tcx.sess
+    }
+
+    fn check_overflow(&self) -> bool {
+        self.check_overflow
+    }
+
+    fn codegen_unit(&self) -> &'tcx CodegenUnit<'tcx> {
+        self.codegen_unit
+    }
+
+    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]);
+        }
+    }
+
+    fn apply_target_cpu_attr(&self, llfn: &'ll Value) {
+        let mut attrs = SmallVec::<[_; 2]>::new();
+        attrs.push(attributes::target_cpu_attr(self));
+        attrs.extend(attributes::tune_cpu_attr(self));
+        attributes::apply_to_llfn(llfn, llvm::AttributePlace::Function, &attrs);
+    }
+
+    fn declare_c_main(&self, fn_type: Self::Type) -> Option<Self::Function> {
+        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(..) {..}
+            // instead of #[start]
+            None
+        }
+    }
+}
+
+impl<'ll> CodegenCx<'ll, '_> {
+    pub(crate) fn get_intrinsic(&self, key: &str) -> (&'ll Type, &'ll Value) {
+        if let Some(v) = self.intrinsics.borrow().get(key).cloned() {
+            return v;
+        }
+
+        self.declare_intrinsic(key).unwrap_or_else(|| bug!("unknown intrinsic '{}'", key))
+    }
+
+    fn insert_intrinsic(
+        &self,
+        name: &'static str,
+        args: Option<&[&'ll llvm::Type]>,
+        ret: &'ll llvm::Type,
+    ) -> (&'ll llvm::Type, &'ll llvm::Value) {
+        let fn_ty = if let Some(args) = args {
+            self.type_func(args, ret)
+        } else {
+            self.type_variadic_func(&[], ret)
+        };
+        let f = self.declare_cfn(name, llvm::UnnamedAddr::No, fn_ty);
+        self.intrinsics.borrow_mut().insert(name, (fn_ty, f));
+        (fn_ty, f)
+    }
+
+    fn declare_intrinsic(&self, key: &str) -> Option<(&'ll Type, &'ll Value)> {
+        macro_rules! ifn {
+            ($name:expr, fn() -> $ret:expr) => (
+                if key == $name {
+                    return Some(self.insert_intrinsic($name, Some(&[]), $ret));
+                }
+            );
+            ($name:expr, fn(...) -> $ret:expr) => (
+                if key == $name {
+                    return Some(self.insert_intrinsic($name, None, $ret));
+                }
+            );
+            ($name:expr, fn($($arg:expr),*) -> $ret:expr) => (
+                if key == $name {
+                    return Some(self.insert_intrinsic($name, Some(&[$($arg),*]), $ret));
+                }
+            );
+        }
+        macro_rules! mk_struct {
+            ($($field_ty:expr),*) => (self.type_struct( &[$($field_ty),*], false))
+        }
+
+        let ptr = self.type_ptr();
+        let void = self.type_void();
+        let i1 = self.type_i1();
+        let t_i8 = self.type_i8();
+        let t_i16 = self.type_i16();
+        let t_i32 = self.type_i32();
+        let t_i64 = self.type_i64();
+        let t_i128 = self.type_i128();
+        let t_isize = self.type_isize();
+        let t_f16 = self.type_f16();
+        let t_f32 = self.type_f32();
+        let t_f64 = self.type_f64();
+        let t_f128 = self.type_f128();
+        let t_metadata = self.type_metadata();
+        let t_token = self.type_token();
+
+        ifn!("llvm.wasm.get.exception", fn(t_token) -> ptr);
+        ifn!("llvm.wasm.get.ehselector", fn(t_token) -> t_i32);
+
+        ifn!("llvm.wasm.trunc.unsigned.i32.f32", fn(t_f32) -> t_i32);
+        ifn!("llvm.wasm.trunc.unsigned.i32.f64", fn(t_f64) -> t_i32);
+        ifn!("llvm.wasm.trunc.unsigned.i64.f32", fn(t_f32) -> t_i64);
+        ifn!("llvm.wasm.trunc.unsigned.i64.f64", fn(t_f64) -> t_i64);
+        ifn!("llvm.wasm.trunc.signed.i32.f32", fn(t_f32) -> t_i32);
+        ifn!("llvm.wasm.trunc.signed.i32.f64", fn(t_f64) -> t_i32);
+        ifn!("llvm.wasm.trunc.signed.i64.f32", fn(t_f32) -> t_i64);
+        ifn!("llvm.wasm.trunc.signed.i64.f64", fn(t_f64) -> t_i64);
+
+        ifn!("llvm.fptosi.sat.i8.f32", fn(t_f32) -> t_i8);
+        ifn!("llvm.fptosi.sat.i16.f32", fn(t_f32) -> t_i16);
+        ifn!("llvm.fptosi.sat.i32.f32", fn(t_f32) -> t_i32);
+        ifn!("llvm.fptosi.sat.i64.f32", fn(t_f32) -> t_i64);
+        ifn!("llvm.fptosi.sat.i128.f32", fn(t_f32) -> t_i128);
+        ifn!("llvm.fptosi.sat.i8.f64", fn(t_f64) -> t_i8);
+        ifn!("llvm.fptosi.sat.i16.f64", fn(t_f64) -> t_i16);
+        ifn!("llvm.fptosi.sat.i32.f64", fn(t_f64) -> t_i32);
+        ifn!("llvm.fptosi.sat.i64.f64", fn(t_f64) -> t_i64);
+        ifn!("llvm.fptosi.sat.i128.f64", fn(t_f64) -> t_i128);
+
+        ifn!("llvm.fptoui.sat.i8.f32", fn(t_f32) -> t_i8);
+        ifn!("llvm.fptoui.sat.i16.f32", fn(t_f32) -> t_i16);
+        ifn!("llvm.fptoui.sat.i32.f32", fn(t_f32) -> t_i32);
+        ifn!("llvm.fptoui.sat.i64.f32", fn(t_f32) -> t_i64);
+        ifn!("llvm.fptoui.sat.i128.f32", fn(t_f32) -> t_i128);
+        ifn!("llvm.fptoui.sat.i8.f64", fn(t_f64) -> t_i8);
+        ifn!("llvm.fptoui.sat.i16.f64", fn(t_f64) -> t_i16);
+        ifn!("llvm.fptoui.sat.i32.f64", fn(t_f64) -> t_i32);
+        ifn!("llvm.fptoui.sat.i64.f64", fn(t_f64) -> t_i64);
+        ifn!("llvm.fptoui.sat.i128.f64", fn(t_f64) -> t_i128);
+
+        ifn!("llvm.trap", fn() -> void);
+        ifn!("llvm.debugtrap", fn() -> void);
+        ifn!("llvm.frameaddress", fn(t_i32) -> ptr);
+
+        ifn!("llvm.powi.f16", fn(t_f16, t_i32) -> t_f16);
+        ifn!("llvm.powi.f32", fn(t_f32, t_i32) -> t_f32);
+        ifn!("llvm.powi.f64", fn(t_f64, t_i32) -> t_f64);
+        ifn!("llvm.powi.f128", fn(t_f128, t_i32) -> t_f128);
+
+        ifn!("llvm.pow.f16", fn(t_f16, t_f16) -> t_f16);
+        ifn!("llvm.pow.f32", fn(t_f32, t_f32) -> t_f32);
+        ifn!("llvm.pow.f64", fn(t_f64, t_f64) -> t_f64);
+        ifn!("llvm.pow.f128", fn(t_f128, t_f128) -> t_f128);
+
+        ifn!("llvm.sqrt.f16", fn(t_f16) -> t_f16);
+        ifn!("llvm.sqrt.f32", fn(t_f32) -> t_f32);
+        ifn!("llvm.sqrt.f64", fn(t_f64) -> t_f64);
+        ifn!("llvm.sqrt.f128", fn(t_f128) -> t_f128);
+
+        ifn!("llvm.sin.f16", fn(t_f16) -> t_f16);
+        ifn!("llvm.sin.f32", fn(t_f32) -> t_f32);
+        ifn!("llvm.sin.f64", fn(t_f64) -> t_f64);
+        ifn!("llvm.sin.f128", fn(t_f128) -> t_f128);
+
+        ifn!("llvm.cos.f16", fn(t_f16) -> t_f16);
+        ifn!("llvm.cos.f32", fn(t_f32) -> t_f32);
+        ifn!("llvm.cos.f64", fn(t_f64) -> t_f64);
+        ifn!("llvm.cos.f128", fn(t_f128) -> t_f128);
+
+        ifn!("llvm.exp.f16", fn(t_f16) -> t_f16);
+        ifn!("llvm.exp.f32", fn(t_f32) -> t_f32);
+        ifn!("llvm.exp.f64", fn(t_f64) -> t_f64);
+        ifn!("llvm.exp.f128", fn(t_f128) -> t_f128);
+
+        ifn!("llvm.exp2.f16", fn(t_f16) -> t_f16);
+        ifn!("llvm.exp2.f32", fn(t_f32) -> t_f32);
+        ifn!("llvm.exp2.f64", fn(t_f64) -> t_f64);
+        ifn!("llvm.exp2.f128", fn(t_f128) -> t_f128);
+
+        ifn!("llvm.log.f16", fn(t_f16) -> t_f16);
+        ifn!("llvm.log.f32", fn(t_f32) -> t_f32);
+        ifn!("llvm.log.f64", fn(t_f64) -> t_f64);
+        ifn!("llvm.log.f128", fn(t_f128) -> t_f128);
+
+        ifn!("llvm.log10.f16", fn(t_f16) -> t_f16);
+        ifn!("llvm.log10.f32", fn(t_f32) -> t_f32);
+        ifn!("llvm.log10.f64", fn(t_f64) -> t_f64);
+        ifn!("llvm.log10.f128", fn(t_f128) -> t_f128);
+
+        ifn!("llvm.log2.f16", fn(t_f16) -> t_f16);
+        ifn!("llvm.log2.f32", fn(t_f32) -> t_f32);
+        ifn!("llvm.log2.f64", fn(t_f64) -> t_f64);
+        ifn!("llvm.log2.f128", fn(t_f128) -> t_f128);
+
+        ifn!("llvm.fma.f16", fn(t_f16, t_f16, t_f16) -> t_f16);
+        ifn!("llvm.fma.f32", fn(t_f32, t_f32, t_f32) -> t_f32);
+        ifn!("llvm.fma.f64", fn(t_f64, t_f64, t_f64) -> t_f64);
+        ifn!("llvm.fma.f128", fn(t_f128, t_f128, t_f128) -> t_f128);
+
+        ifn!("llvm.fabs.f16", fn(t_f16) -> t_f16);
+        ifn!("llvm.fabs.f32", fn(t_f32) -> t_f32);
+        ifn!("llvm.fabs.f64", fn(t_f64) -> t_f64);
+        ifn!("llvm.fabs.f128", fn(t_f128) -> t_f128);
+
+        ifn!("llvm.minnum.f16", fn(t_f16, t_f16) -> t_f16);
+        ifn!("llvm.minnum.f32", fn(t_f32, t_f32) -> t_f32);
+        ifn!("llvm.minnum.f64", fn(t_f64, t_f64) -> t_f64);
+        ifn!("llvm.minnum.f128", fn(t_f128, t_f128) -> t_f128);
+
+        ifn!("llvm.maxnum.f16", fn(t_f16, t_f16) -> t_f16);
+        ifn!("llvm.maxnum.f32", fn(t_f32, t_f32) -> t_f32);
+        ifn!("llvm.maxnum.f64", fn(t_f64, t_f64) -> t_f64);
+        ifn!("llvm.maxnum.f128", fn(t_f128, t_f128) -> t_f128);
+
+        ifn!("llvm.floor.f16", fn(t_f16) -> t_f16);
+        ifn!("llvm.floor.f32", fn(t_f32) -> t_f32);
+        ifn!("llvm.floor.f64", fn(t_f64) -> t_f64);
+        ifn!("llvm.floor.f128", fn(t_f128) -> t_f128);
+
+        ifn!("llvm.ceil.f16", fn(t_f16) -> t_f16);
+        ifn!("llvm.ceil.f32", fn(t_f32) -> t_f32);
+        ifn!("llvm.ceil.f64", fn(t_f64) -> t_f64);
+        ifn!("llvm.ceil.f128", fn(t_f128) -> t_f128);
+
+        ifn!("llvm.trunc.f16", fn(t_f16) -> t_f16);
+        ifn!("llvm.trunc.f32", fn(t_f32) -> t_f32);
+        ifn!("llvm.trunc.f64", fn(t_f64) -> t_f64);
+        ifn!("llvm.trunc.f128", fn(t_f128) -> t_f128);
+
+        ifn!("llvm.copysign.f16", fn(t_f16, t_f16) -> t_f16);
+        ifn!("llvm.copysign.f32", fn(t_f32, t_f32) -> t_f32);
+        ifn!("llvm.copysign.f64", fn(t_f64, t_f64) -> t_f64);
+        ifn!("llvm.copysign.f128", fn(t_f128, t_f128) -> t_f128);
+
+        ifn!("llvm.round.f16", fn(t_f16) -> t_f16);
+        ifn!("llvm.round.f32", fn(t_f32) -> t_f32);
+        ifn!("llvm.round.f64", fn(t_f64) -> t_f64);
+        ifn!("llvm.round.f128", fn(t_f128) -> t_f128);
+
+        ifn!("llvm.roundeven.f16", fn(t_f16) -> t_f16);
+        ifn!("llvm.roundeven.f32", fn(t_f32) -> t_f32);
+        ifn!("llvm.roundeven.f64", fn(t_f64) -> t_f64);
+        ifn!("llvm.roundeven.f128", fn(t_f128) -> t_f128);
+
+        ifn!("llvm.rint.f16", fn(t_f16) -> t_f16);
+        ifn!("llvm.rint.f32", fn(t_f32) -> t_f32);
+        ifn!("llvm.rint.f64", fn(t_f64) -> t_f64);
+        ifn!("llvm.rint.f128", fn(t_f128) -> t_f128);
+
+        ifn!("llvm.nearbyint.f16", fn(t_f16) -> t_f16);
+        ifn!("llvm.nearbyint.f32", fn(t_f32) -> t_f32);
+        ifn!("llvm.nearbyint.f64", fn(t_f64) -> t_f64);
+        ifn!("llvm.nearbyint.f128", fn(t_f128) -> t_f128);
+
+        ifn!("llvm.ctpop.i8", fn(t_i8) -> t_i8);
+        ifn!("llvm.ctpop.i16", fn(t_i16) -> t_i16);
+        ifn!("llvm.ctpop.i32", fn(t_i32) -> t_i32);
+        ifn!("llvm.ctpop.i64", fn(t_i64) -> t_i64);
+        ifn!("llvm.ctpop.i128", fn(t_i128) -> t_i128);
+
+        ifn!("llvm.ctlz.i8", fn(t_i8, i1) -> t_i8);
+        ifn!("llvm.ctlz.i16", fn(t_i16, i1) -> t_i16);
+        ifn!("llvm.ctlz.i32", fn(t_i32, i1) -> t_i32);
+        ifn!("llvm.ctlz.i64", fn(t_i64, i1) -> t_i64);
+        ifn!("llvm.ctlz.i128", fn(t_i128, i1) -> t_i128);
+
+        ifn!("llvm.cttz.i8", fn(t_i8, i1) -> t_i8);
+        ifn!("llvm.cttz.i16", fn(t_i16, i1) -> t_i16);
+        ifn!("llvm.cttz.i32", fn(t_i32, i1) -> t_i32);
+        ifn!("llvm.cttz.i64", fn(t_i64, i1) -> t_i64);
+        ifn!("llvm.cttz.i128", fn(t_i128, i1) -> t_i128);
+
+        ifn!("llvm.bswap.i16", fn(t_i16) -> t_i16);
+        ifn!("llvm.bswap.i32", fn(t_i32) -> t_i32);
+        ifn!("llvm.bswap.i64", fn(t_i64) -> t_i64);
+        ifn!("llvm.bswap.i128", fn(t_i128) -> t_i128);
+
+        ifn!("llvm.bitreverse.i8", fn(t_i8) -> t_i8);
+        ifn!("llvm.bitreverse.i16", fn(t_i16) -> t_i16);
+        ifn!("llvm.bitreverse.i32", fn(t_i32) -> t_i32);
+        ifn!("llvm.bitreverse.i64", fn(t_i64) -> t_i64);
+        ifn!("llvm.bitreverse.i128", fn(t_i128) -> t_i128);
+
+        ifn!("llvm.fshl.i8", fn(t_i8, t_i8, t_i8) -> t_i8);
+        ifn!("llvm.fshl.i16", fn(t_i16, t_i16, t_i16) -> t_i16);
+        ifn!("llvm.fshl.i32", fn(t_i32, t_i32, t_i32) -> t_i32);
+        ifn!("llvm.fshl.i64", fn(t_i64, t_i64, t_i64) -> t_i64);
+        ifn!("llvm.fshl.i128", fn(t_i128, t_i128, t_i128) -> t_i128);
+
+        ifn!("llvm.fshr.i8", fn(t_i8, t_i8, t_i8) -> t_i8);
+        ifn!("llvm.fshr.i16", fn(t_i16, t_i16, t_i16) -> t_i16);
+        ifn!("llvm.fshr.i32", fn(t_i32, t_i32, t_i32) -> t_i32);
+        ifn!("llvm.fshr.i64", fn(t_i64, t_i64, t_i64) -> t_i64);
+        ifn!("llvm.fshr.i128", fn(t_i128, t_i128, t_i128) -> t_i128);
+
+        ifn!("llvm.sadd.with.overflow.i8", fn(t_i8, t_i8) -> mk_struct! {t_i8, i1});
+        ifn!("llvm.sadd.with.overflow.i16", fn(t_i16, t_i16) -> mk_struct! {t_i16, i1});
+        ifn!("llvm.sadd.with.overflow.i32", fn(t_i32, t_i32) -> mk_struct! {t_i32, i1});
+        ifn!("llvm.sadd.with.overflow.i64", fn(t_i64, t_i64) -> mk_struct! {t_i64, i1});
+        ifn!("llvm.sadd.with.overflow.i128", fn(t_i128, t_i128) -> mk_struct! {t_i128, i1});
+
+        ifn!("llvm.uadd.with.overflow.i8", fn(t_i8, t_i8) -> mk_struct! {t_i8, i1});
+        ifn!("llvm.uadd.with.overflow.i16", fn(t_i16, t_i16) -> mk_struct! {t_i16, i1});
+        ifn!("llvm.uadd.with.overflow.i32", fn(t_i32, t_i32) -> mk_struct! {t_i32, i1});
+        ifn!("llvm.uadd.with.overflow.i64", fn(t_i64, t_i64) -> mk_struct! {t_i64, i1});
+        ifn!("llvm.uadd.with.overflow.i128", fn(t_i128, t_i128) -> mk_struct! {t_i128, i1});
+
+        ifn!("llvm.ssub.with.overflow.i8", fn(t_i8, t_i8) -> mk_struct! {t_i8, i1});
+        ifn!("llvm.ssub.with.overflow.i16", fn(t_i16, t_i16) -> mk_struct! {t_i16, i1});
+        ifn!("llvm.ssub.with.overflow.i32", fn(t_i32, t_i32) -> mk_struct! {t_i32, i1});
+        ifn!("llvm.ssub.with.overflow.i64", fn(t_i64, t_i64) -> mk_struct! {t_i64, i1});
+        ifn!("llvm.ssub.with.overflow.i128", fn(t_i128, t_i128) -> mk_struct! {t_i128, i1});
+
+        ifn!("llvm.usub.with.overflow.i8", fn(t_i8, t_i8) -> mk_struct! {t_i8, i1});
+        ifn!("llvm.usub.with.overflow.i16", fn(t_i16, t_i16) -> mk_struct! {t_i16, i1});
+        ifn!("llvm.usub.with.overflow.i32", fn(t_i32, t_i32) -> mk_struct! {t_i32, i1});
+        ifn!("llvm.usub.with.overflow.i64", fn(t_i64, t_i64) -> mk_struct! {t_i64, i1});
+        ifn!("llvm.usub.with.overflow.i128", fn(t_i128, t_i128) -> mk_struct! {t_i128, i1});
+
+        ifn!("llvm.smul.with.overflow.i8", fn(t_i8, t_i8) -> mk_struct! {t_i8, i1});
+        ifn!("llvm.smul.with.overflow.i16", fn(t_i16, t_i16) -> mk_struct! {t_i16, i1});
+        ifn!("llvm.smul.with.overflow.i32", fn(t_i32, t_i32) -> mk_struct! {t_i32, i1});
+        ifn!("llvm.smul.with.overflow.i64", fn(t_i64, t_i64) -> mk_struct! {t_i64, i1});
+        ifn!("llvm.smul.with.overflow.i128", fn(t_i128, t_i128) -> mk_struct! {t_i128, i1});
+
+        ifn!("llvm.umul.with.overflow.i8", fn(t_i8, t_i8) -> mk_struct! {t_i8, i1});
+        ifn!("llvm.umul.with.overflow.i16", fn(t_i16, t_i16) -> mk_struct! {t_i16, i1});
+        ifn!("llvm.umul.with.overflow.i32", fn(t_i32, t_i32) -> mk_struct! {t_i32, i1});
+        ifn!("llvm.umul.with.overflow.i64", fn(t_i64, t_i64) -> mk_struct! {t_i64, i1});
+        ifn!("llvm.umul.with.overflow.i128", fn(t_i128, t_i128) -> mk_struct! {t_i128, i1});
+
+        ifn!("llvm.sadd.sat.i8", fn(t_i8, t_i8) -> t_i8);
+        ifn!("llvm.sadd.sat.i16", fn(t_i16, t_i16) -> t_i16);
+        ifn!("llvm.sadd.sat.i32", fn(t_i32, t_i32) -> t_i32);
+        ifn!("llvm.sadd.sat.i64", fn(t_i64, t_i64) -> t_i64);
+        ifn!("llvm.sadd.sat.i128", fn(t_i128, t_i128) -> t_i128);
+
+        ifn!("llvm.uadd.sat.i8", fn(t_i8, t_i8) -> t_i8);
+        ifn!("llvm.uadd.sat.i16", fn(t_i16, t_i16) -> t_i16);
+        ifn!("llvm.uadd.sat.i32", fn(t_i32, t_i32) -> t_i32);
+        ifn!("llvm.uadd.sat.i64", fn(t_i64, t_i64) -> t_i64);
+        ifn!("llvm.uadd.sat.i128", fn(t_i128, t_i128) -> t_i128);
+
+        ifn!("llvm.ssub.sat.i8", fn(t_i8, t_i8) -> t_i8);
+        ifn!("llvm.ssub.sat.i16", fn(t_i16, t_i16) -> t_i16);
+        ifn!("llvm.ssub.sat.i32", fn(t_i32, t_i32) -> t_i32);
+        ifn!("llvm.ssub.sat.i64", fn(t_i64, t_i64) -> t_i64);
+        ifn!("llvm.ssub.sat.i128", fn(t_i128, t_i128) -> t_i128);
+
+        ifn!("llvm.usub.sat.i8", fn(t_i8, t_i8) -> t_i8);
+        ifn!("llvm.usub.sat.i16", fn(t_i16, t_i16) -> t_i16);
+        ifn!("llvm.usub.sat.i32", fn(t_i32, t_i32) -> t_i32);
+        ifn!("llvm.usub.sat.i64", fn(t_i64, t_i64) -> t_i64);
+        ifn!("llvm.usub.sat.i128", fn(t_i128, t_i128) -> t_i128);
+
+        ifn!("llvm.lifetime.start.p0i8", fn(t_i64, ptr) -> void);
+        ifn!("llvm.lifetime.end.p0i8", fn(t_i64, ptr) -> void);
+
+        // FIXME: This is an infinitesimally small portion of the types you can
+        // pass to this intrinsic, if we can ever lazily register intrinsics we
+        // should register these when they're used, that way any type can be
+        // passed.
+        ifn!("llvm.is.constant.i1", fn(i1) -> i1);
+        ifn!("llvm.is.constant.i8", fn(t_i8) -> i1);
+        ifn!("llvm.is.constant.i16", fn(t_i16) -> i1);
+        ifn!("llvm.is.constant.i32", fn(t_i32) -> i1);
+        ifn!("llvm.is.constant.i64", fn(t_i64) -> i1);
+        ifn!("llvm.is.constant.i128", fn(t_i128) -> i1);
+        ifn!("llvm.is.constant.isize", fn(t_isize) -> i1);
+        ifn!("llvm.is.constant.f32", fn(t_f32) -> i1);
+        ifn!("llvm.is.constant.f64", fn(t_f64) -> i1);
+        ifn!("llvm.is.constant.ptr", fn(ptr) -> i1);
+
+        ifn!("llvm.expect.i1", fn(i1, i1) -> i1);
+        ifn!("llvm.eh.typeid.for", fn(ptr) -> t_i32);
+        ifn!("llvm.localescape", fn(...) -> void);
+        ifn!("llvm.localrecover", fn(ptr, ptr, t_i32) -> ptr);
+        ifn!("llvm.x86.seh.recoverfp", fn(ptr, ptr) -> ptr);
+
+        ifn!("llvm.assume", fn(i1) -> void);
+        ifn!("llvm.prefetch", fn(ptr, t_i32, t_i32, t_i32) -> void);
+
+        // This isn't an "LLVM intrinsic", but LLVM's optimization passes
+        // recognize it like one (including turning it into `bcmp` sometimes)
+        // and we use it to implement intrinsics like `raw_eq` and `compare_bytes`
+        match self.sess().target.arch.as_ref() {
+            "avr" | "msp430" => ifn!("memcmp", fn(ptr, ptr, t_isize) -> t_i16),
+            _ => ifn!("memcmp", fn(ptr, ptr, t_isize) -> t_i32),
+        }
+
+        // variadic intrinsics
+        ifn!("llvm.va_start", fn(ptr) -> void);
+        ifn!("llvm.va_end", fn(ptr) -> void);
+        ifn!("llvm.va_copy", fn(ptr, ptr) -> void);
+
+        if self.sess().instrument_coverage() {
+            ifn!("llvm.instrprof.increment", fn(ptr, t_i64, t_i32, t_i32) -> void);
+        }
+
+        ifn!("llvm.type.test", fn(ptr, t_metadata) -> i1);
+        ifn!("llvm.type.checked.load", fn(ptr, t_i32, t_metadata) -> mk_struct! {ptr, i1});
+
+        if self.sess().opts.debuginfo != DebugInfo::None {
+            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(ptr, t_isize) -> ptr);
+
+        None
+    }
+
+    pub(crate) fn eh_catch_typeinfo(&self) -> &'ll Value {
+        if let Some(eh_catch_typeinfo) = self.eh_catch_typeinfo.get() {
+            return eh_catch_typeinfo;
+        }
+        let tcx = self.tcx;
+        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),
+            _ => {
+                let ty = self.type_struct(&[self.type_ptr(), self.type_ptr()], false);
+                self.declare_global("rust_eh_catch_typeinfo", ty)
+            }
+        };
+        self.eh_catch_typeinfo.set(Some(eh_catch_typeinfo));
+        eh_catch_typeinfo
+    }
+}
+
+impl CodegenCx<'_, '_> {
+    /// Generates a new symbol name with the given prefix. This symbol name must
+    /// only be used for definitions with `internal` or `private` linkage.
+    pub fn generate_local_symbol_name(&self, prefix: &str) -> String {
+        let idx = self.local_gen_sym_counter.get();
+        self.local_gen_sym_counter.set(idx + 1);
+        // Include a '.' character, so there can be no accidental conflicts with
+        // user defined names
+        let mut name = String::with_capacity(prefix.len() + 6);
+        name.push_str(prefix);
+        name.push('.');
+        name.push_str(&(idx as u64).to_base(ALPHANUMERIC_ONLY));
+        name
+    }
+}
+
+impl HasDataLayout for CodegenCx<'_, '_> {
+    #[inline]
+    fn data_layout(&self) -> &TargetDataLayout {
+        &self.tcx.data_layout
+    }
+}
+
+impl HasTargetSpec for CodegenCx<'_, '_> {
+    #[inline]
+    fn target_spec(&self) -> &Target {
+        &self.tcx.sess.target
+    }
+}
+
+impl<'tcx> ty::layout::HasTyCtxt<'tcx> for CodegenCx<'_, 'tcx> {
+    #[inline]
+    fn tcx(&self) -> TyCtxt<'tcx> {
+        self.tcx
+    }
+}
+
+impl<'tcx, 'll> HasParamEnv<'tcx> for CodegenCx<'ll, 'tcx> {
+    fn param_env(&self) -> ty::ParamEnv<'tcx> {
+        ty::ParamEnv::reveal_all()
+    }
+}
+
+impl<'tcx> LayoutOfHelpers<'tcx> for CodegenCx<'_, 'tcx> {
+    type LayoutOfResult = TyAndLayout<'tcx>;
+
+    #[inline]
+    fn handle_layout_err(&self, err: LayoutError<'tcx>, span: Span, ty: Ty<'tcx>) -> ! {
+        if let LayoutError::SizeOverflow(_) | LayoutError::ReferencesError(_) = err {
+            self.tcx.dcx().emit_fatal(Spanned { span, node: err.into_diagnostic() })
+        } else {
+            self.tcx.dcx().emit_fatal(ssa_errors::FailedToGetLayout { span, ty, err })
+        }
+    }
+}
+
+impl<'tcx> FnAbiOfHelpers<'tcx> for CodegenCx<'_, 'tcx> {
+    type FnAbiOfResult = &'tcx FnAbi<'tcx, Ty<'tcx>>;
+
+    #[inline]
+    fn handle_fn_abi_err(
+        &self,
+        err: FnAbiError<'tcx>,
+        span: Span,
+        fn_abi_request: FnAbiRequest<'tcx>,
+    ) -> ! {
+        if let FnAbiError::Layout(LayoutError::SizeOverflow(_)) = err {
+            self.tcx.dcx().emit_fatal(Spanned { span, node: err })
+        } else {
+            match fn_abi_request {
+                FnAbiRequest::OfFnPtr { sig, extra_args } => {
+                    span_bug!(span, "`fn_abi_of_fn_ptr({sig}, {extra_args:?})` failed: {err:?}",);
+                }
+                FnAbiRequest::OfInstance { instance, extra_args } => {
+                    span_bug!(
+                        span,
+                        "`fn_abi_of_instance({instance}, {extra_args:?})` failed: {err:?}",
+                    );
+                }
+            }
+        }
+    }
+}