Auto merge of #81451 - nikic:llvm-12, r=nagisa

Upgrade to LLVM 12

This implements the necessary adjustments to make rustc work with LLVM 12. I didn't encounter any major issues so far.

r? `@cuviper`

57 files changed, 401 insertions, 100 deletions

diff --git a/.gitmodules b/.gitmodules
index 40e6fc2c19d..8618f61f04a 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -37,7 +37,7 @@
 [submodule "src/llvm-project"]
 	path = src/llvm-project
 	url = https://github.com/rust-lang/llvm-project.git
-	branch = rustc/11.0-2021-01-05
+	branch = rustc/12.0-2021-02-03
 [submodule "src/doc/embedded-book"]
 	path = src/doc/embedded-book
 	url = https://github.com/rust-embedded/book.git
diff --git a/compiler/rustc_codegen_llvm/src/abi.rs b/compiler/rustc_codegen_llvm/src/abi.rs
index d714ff1fe9b..d9393ffe534 100644
--- a/compiler/rustc_codegen_llvm/src/abi.rs
+++ b/compiler/rustc_codegen_llvm/src/abi.rs
@@ -430,7 +430,13 @@ impl<'tcx> FnAbiLlvmExt<'tcx> for FnAbi<'tcx, Ty<'tcx>> {
             PassMode::Indirect { ref attrs, extra_attrs: _, on_stack } => {
                 assert!(!on_stack);
                 let i = apply(attrs);
-                llvm::Attribute::StructRet.apply_llfn(llvm::AttributePlace::Argument(i), llfn);
+                unsafe {
+                    llvm::LLVMRustAddStructRetAttr(
+                        llfn,
+                        llvm::AttributePlace::Argument(i).as_uint(),
+                        self.ret.layout.llvm_type(cx),
+                    );
+                }
             }
             _ => {}
         }
@@ -486,8 +492,13 @@ impl<'tcx> FnAbiLlvmExt<'tcx> for FnAbi<'tcx, Ty<'tcx>> {
             PassMode::Indirect { ref attrs, extra_attrs: _, on_stack } => {
                 assert!(!on_stack);
                 let i = apply(attrs);
-                llvm::Attribute::StructRet
-                    .apply_callsite(llvm::AttributePlace::Argument(i), callsite);
+                unsafe {
+                    llvm::LLVMRustAddStructRetCallSiteAttr(
+                        callsite,
+                        llvm::AttributePlace::Argument(i).as_uint(),
+                        self.ret.layout.llvm_type(bx),
+                    );
+                }
             }
             _ => {}
         }
diff --git a/compiler/rustc_codegen_llvm/src/asm.rs b/compiler/rustc_codegen_llvm/src/asm.rs
index 26815de403f..38c8ae711a4 100644
--- a/compiler/rustc_codegen_llvm/src/asm.rs
+++ b/compiler/rustc_codegen_llvm/src/asm.rs
@@ -304,6 +304,7 @@ impl AsmBuilderMethods<'tcx> for Builder<'a, 'll, 'tcx> {
             } else if options.contains(InlineAsmOptions::READONLY) {
                 llvm::Attribute::ReadOnly.apply_callsite(llvm::AttributePlace::Function, result);
             }
+            llvm::Attribute::WillReturn.apply_callsite(llvm::AttributePlace::Function, result);
         } else if options.contains(InlineAsmOptions::NOMEM) {
             llvm::Attribute::InaccessibleMemOnly
                 .apply_callsite(llvm::AttributePlace::Function, result);
diff --git a/compiler/rustc_codegen_llvm/src/context.rs b/compiler/rustc_codegen_llvm/src/context.rs
index 3ddc7424202..9f6a2ae3ca1 100644
--- a/compiler/rustc_codegen_llvm/src/context.rs
+++ b/compiler/rustc_codegen_llvm/src/context.rs
@@ -104,6 +104,10 @@ fn strip_x86_address_spaces(data_layout: String) -> String {
     data_layout.replace("-p270:32:32-p271:32:32-p272:64:64-", "-")
 }
 
+fn strip_powerpc64_vectors(data_layout: String) -> String {
+    data_layout.replace("-v256:256:256-v512:512:512", "")
+}
+
 pub unsafe fn create_module(
     tcx: TyCtxt<'_>,
     llcx: &'ll llvm::Context,
@@ -119,6 +123,9 @@ pub unsafe fn create_module(
     {
         target_data_layout = strip_x86_address_spaces(target_data_layout);
     }
+    if llvm_util::get_version() < (12, 0, 0) && sess.target.arch == "powerpc64" {
+        target_data_layout = strip_powerpc64_vectors(target_data_layout);
+    }
 
     // Ensure the data-layout values hardcoded remain the defaults.
     if sess.target.is_builtin {
diff --git a/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs b/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs
index e777f363eb0..e47b8fde40f 100644
--- a/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs
+++ b/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs
@@ -162,7 +162,7 @@ pub(crate) fn write_filenames_section_to_buffer<'a>(
 pub(crate) fn write_mapping_to_buffer(
     virtual_file_mapping: Vec<u32>,
     expressions: Vec<CounterExpression>,
-    mut mapping_regions: Vec<CounterMappingRegion>,
+    mapping_regions: Vec<CounterMappingRegion>,
     buffer: &RustString,
 ) {
     unsafe {
@@ -171,7 +171,7 @@ pub(crate) fn write_mapping_to_buffer(
             virtual_file_mapping.len() as c_uint,
             expressions.as_ptr(),
             expressions.len() as c_uint,
-            mapping_regions.as_mut_ptr(),
+            mapping_regions.as_ptr(),
             mapping_regions.len() as c_uint,
             buffer,
         );
diff --git a/compiler/rustc_codegen_llvm/src/llvm/ffi.rs b/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
index 8c1740d8f25..e6d60044c84 100644
--- a/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
+++ b/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
@@ -132,6 +132,7 @@ pub enum Attribute {
     ReadNone = 26,
     InaccessibleMemOnly = 27,
     SanitizeHWAddress = 28,
+    WillReturn = 29,
 }
 
 /// LLVMIntPredicate
@@ -239,6 +240,7 @@ pub enum TypeKind {
     Token = 16,
     ScalableVector = 17,
     BFloat = 18,
+    X86_AMX = 19,
 }
 
 impl TypeKind {
@@ -263,6 +265,7 @@ impl TypeKind {
             TypeKind::Token => rustc_codegen_ssa::common::TypeKind::Token,
             TypeKind::ScalableVector => rustc_codegen_ssa::common::TypeKind::ScalableVector,
             TypeKind::BFloat => rustc_codegen_ssa::common::TypeKind::BFloat,
+            TypeKind::X86_AMX => rustc_codegen_ssa::common::TypeKind::X86_AMX,
         }
     }
 }
@@ -674,9 +677,7 @@ pub mod coverageinfo {
     /// array", encoded separately), and source location (start and end positions of the represented
     /// code region).
     ///
-    /// Aligns with [llvm::coverage::CounterMappingRegion](https://github.com/rust-lang/llvm-project/blob/rustc/11.0-2020-10-12/llvm/include/llvm/ProfileData/Coverage/CoverageMapping.h#L224-L227)
-    /// Important: The Rust struct layout (order and types of fields) must match its C++
-    /// counterpart.
+    /// Matches LLVMRustCounterMappingRegion.
     #[derive(Copy, Clone, Debug)]
     #[repr(C)]
     pub struct CounterMappingRegion {
@@ -1073,6 +1074,7 @@ extern "C" {
     pub fn LLVMRustAddDereferenceableAttr(Fn: &Value, index: c_uint, bytes: u64);
     pub fn LLVMRustAddDereferenceableOrNullAttr(Fn: &Value, index: c_uint, bytes: u64);
     pub fn LLVMRustAddByValAttr(Fn: &Value, index: c_uint, ty: &Type);
+    pub fn LLVMRustAddStructRetAttr(Fn: &Value, index: c_uint, ty: &Type);
     pub fn LLVMRustAddFunctionAttribute(Fn: &Value, index: c_uint, attr: Attribute);
     pub fn LLVMRustAddFunctionAttrStringValue(
         Fn: &Value,
@@ -1108,6 +1110,7 @@ extern "C" {
     pub fn LLVMRustAddDereferenceableCallSiteAttr(Instr: &Value, index: c_uint, bytes: u64);
     pub fn LLVMRustAddDereferenceableOrNullCallSiteAttr(Instr: &Value, index: c_uint, bytes: u64);
     pub fn LLVMRustAddByValCallSiteAttr(Instr: &Value, index: c_uint, ty: &Type);
+    pub fn LLVMRustAddStructRetCallSiteAttr(Instr: &Value, index: c_uint, ty: &Type);
 
     // Operations on load/store instructions (only)
     pub fn LLVMSetVolatile(MemoryAccessInst: &Value, volatile: Bool);
@@ -1792,7 +1795,7 @@ extern "C" {
         NumVirtualFileMappingIDs: c_uint,
         Expressions: *const coverage_map::CounterExpression,
         NumExpressions: c_uint,
-        MappingRegions: *mut coverageinfo::CounterMappingRegion,
+        MappingRegions: *const coverageinfo::CounterMappingRegion,
         NumMappingRegions: c_uint,
         BufferOut: &RustString,
     );
diff --git a/compiler/rustc_codegen_ssa/src/common.rs b/compiler/rustc_codegen_ssa/src/common.rs
index 780b1d2cd94..afd83bfcb56 100644
--- a/compiler/rustc_codegen_ssa/src/common.rs
+++ b/compiler/rustc_codegen_ssa/src/common.rs
@@ -95,6 +95,7 @@ pub enum TypeKind {
     Token,
     ScalableVector,
     BFloat,
+    X86_AMX,
 }
 
 // FIXME(mw): Anything that is produced via DepGraph::with_task() must implement
diff --git a/compiler/rustc_llvm/llvm-wrapper/CoverageMappingWrapper.cpp b/compiler/rustc_llvm/llvm-wrapper/CoverageMappingWrapper.cpp
index 25badc3f4e1..e97d96e3a4e 100644
--- a/compiler/rustc_llvm/llvm-wrapper/CoverageMappingWrapper.cpp
+++ b/compiler/rustc_llvm/llvm-wrapper/CoverageMappingWrapper.cpp
@@ -8,6 +8,17 @@
 
 using namespace llvm;
 
+struct LLVMRustCounterMappingRegion {
+  coverage::Counter Count;
+  uint32_t FileID;
+  uint32_t ExpandedFileID;
+  uint32_t LineStart;
+  uint32_t ColumnStart;
+  uint32_t LineEnd;
+  uint32_t ColumnEnd;
+  coverage::CounterMappingRegion::RegionKind Kind;
+};
+
 extern "C" void LLVMRustCoverageWriteFilenamesSectionToBuffer(
     const char* const Filenames[],
     size_t FilenamesLen,
@@ -27,13 +38,22 @@ extern "C" void LLVMRustCoverageWriteMappingToBuffer(
     unsigned NumVirtualFileMappingIDs,
     const coverage::CounterExpression *Expressions,
     unsigned NumExpressions,
-    coverage::CounterMappingRegion *MappingRegions,
+    LLVMRustCounterMappingRegion *RustMappingRegions,
     unsigned NumMappingRegions,
     RustStringRef BufferOut) {
+  // Convert from FFI representation to LLVM representation.
+  SmallVector<coverage::CounterMappingRegion, 0> MappingRegions;
+  MappingRegions.reserve(NumMappingRegions);
+  for (const auto &Region : makeArrayRef(RustMappingRegions, NumMappingRegions)) {
+    MappingRegions.emplace_back(
+        Region.Count, Region.FileID, Region.ExpandedFileID,
+        Region.LineStart, Region.ColumnStart, Region.LineEnd, Region.ColumnEnd,
+        Region.Kind);
+  }
   auto CoverageMappingWriter = coverage::CoverageMappingWriter(
       makeArrayRef(VirtualFileMappingIDs, NumVirtualFileMappingIDs),
       makeArrayRef(Expressions, NumExpressions),
-      makeMutableArrayRef(MappingRegions, NumMappingRegions));
+      MappingRegions);
   RawRustStringOstream OS(BufferOut);
   CoverageMappingWriter.write(OS);
 }
diff --git a/compiler/rustc_llvm/llvm-wrapper/LLVMWrapper.h b/compiler/rustc_llvm/llvm-wrapper/LLVMWrapper.h
index 0e3bf5615af..f67e06706ea 100644
--- a/compiler/rustc_llvm/llvm-wrapper/LLVMWrapper.h
+++ b/compiler/rustc_llvm/llvm-wrapper/LLVMWrapper.h
@@ -86,6 +86,7 @@ enum LLVMRustAttribute {
   ReadNone = 26,
   InaccessibleMemOnly = 27,
   SanitizeHWAddress = 28,
+  WillReturn = 29,
 };
 
 typedef struct OpaqueRustString *RustStringRef;
diff --git a/compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp b/compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp
index 5263d5dcf3e..2f28162f908 100644
--- a/compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp
+++ b/compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp
@@ -5,6 +5,7 @@
 
 #include "LLVMWrapper.h"
 
+#include "llvm/Analysis/AliasAnalysis.h"
 #include "llvm/Analysis/TargetLibraryInfo.h"
 #include "llvm/Analysis/TargetTransformInfo.h"
 #include "llvm/CodeGen/TargetSubtargetInfo.h"
@@ -683,6 +684,25 @@ void LLVMSelfProfileInitializeCallbacks(
     PassInstrumentationCallbacks& PIC, void* LlvmSelfProfiler,
     LLVMRustSelfProfileBeforePassCallback BeforePassCallback,
     LLVMRustSelfProfileAfterPassCallback AfterPassCallback) {
+#if LLVM_VERSION_GE(12, 0)
+  PIC.registerBeforeNonSkippedPassCallback([LlvmSelfProfiler, BeforePassCallback](
+                                           StringRef Pass, llvm::Any Ir) {
+    std::string PassName = Pass.str();
+    std::string IrName = LLVMRustwrappedIrGetName(Ir);
+    BeforePassCallback(LlvmSelfProfiler, PassName.c_str(), IrName.c_str());
+  });
+
+  PIC.registerAfterPassCallback(
+      [LlvmSelfProfiler, AfterPassCallback](StringRef Pass, llvm::Any IR,
+                                            const PreservedAnalyses &Preserved) {
+        AfterPassCallback(LlvmSelfProfiler);
+      });
+
+  PIC.registerAfterPassInvalidatedCallback(
+      [LlvmSelfProfiler, AfterPassCallback](StringRef Pass, const PreservedAnalyses &Preserved) {
+        AfterPassCallback(LlvmSelfProfiler);
+      });
+#else
   PIC.registerBeforePassCallback([LlvmSelfProfiler, BeforePassCallback](
                                      StringRef Pass, llvm::Any Ir) {
     std::string PassName = Pass.str();
@@ -700,6 +720,7 @@ void LLVMSelfProfileInitializeCallbacks(
       [LlvmSelfProfiler, AfterPassCallback](StringRef Pass) {
         AfterPassCallback(LlvmSelfProfiler);
       });
+#endif
 
   PIC.registerBeforeAnalysisCallback([LlvmSelfProfiler, BeforePassCallback](
                                          StringRef Pass, llvm::Any Ir) {
@@ -760,8 +781,15 @@ LLVMRustOptimizeWithNewPassManager(
   PTO.LoopVectorization = LoopVectorize;
   PTO.SLPVectorization = SLPVectorize;
 
+  // FIXME: We may want to expose this as an option.
+  bool DebugPassManager = false;
+
   PassInstrumentationCallbacks PIC;
+#if LLVM_VERSION_GE(12, 0)
+  StandardInstrumentations SI(DebugPassManager);
+#else
   StandardInstrumentations SI;
+#endif
   SI.registerCallbacks(PIC);
 
   if (LlvmSelfProfiler){
@@ -777,10 +805,12 @@ LLVMRustOptimizeWithNewPassManager(
     PGOOpt = PGOOptions(PGOUsePath, "", "", PGOOptions::IRUse);
   }
 
+#if LLVM_VERSION_GE(12, 0)
+  PassBuilder PB(DebugPassManager, TM, PTO, PGOOpt, &PIC);
+#else
   PassBuilder PB(TM, PTO, PGOOpt, &PIC);
+#endif
 
-  // FIXME: We may want to expose this as an option.
-  bool DebugPassManager = false;
   LoopAnalysisManager LAM(DebugPassManager);
   FunctionAnalysisManager FAM(DebugPassManager);
   CGSCCAnalysisManager CGAM(DebugPassManager);
@@ -802,7 +832,8 @@ LLVMRustOptimizeWithNewPassManager(
 
   // We manually collect pipeline callbacks so we can apply them at O0, where the
   // PassBuilder does not create a pipeline.
-  std::vector<std::function<void(ModulePassManager &)>> PipelineStartEPCallbacks;
+  std::vector<std::function<void(ModulePassManager &, PassBuilder::OptimizationLevel)>>
+      PipelineStartEPCallbacks;
 #if LLVM_VERSION_GE(11, 0)
   std::vector<std::function<void(ModulePassManager &, PassBuilder::OptimizationLevel)>>
       OptimizerLastEPCallbacks;
@@ -812,9 +843,11 @@ LLVMRustOptimizeWithNewPassManager(
 #endif
 
   if (VerifyIR) {
-    PipelineStartEPCallbacks.push_back([VerifyIR](ModulePassManager &MPM) {
+    PipelineStartEPCallbacks.push_back(
+      [VerifyIR](ModulePassManager &MPM, PassBuilder::OptimizationLevel Level) {
         MPM.addPass(VerifierPass());
-    });
+      }
+    );
   }
 
   if (SanitizerOptions) {
@@ -832,9 +865,11 @@ LLVMRustOptimizeWithNewPassManager(
       );
 #else
 #if LLVM_VERSION_GE(10, 0)
-      PipelineStartEPCallbacks.push_back([Options](ModulePassManager &MPM) {
-        MPM.addPass(MemorySanitizerPass(Options));
-      });
+      PipelineStartEPCallbacks.push_back(
+        [Options](ModulePassManager &MPM, PassBuilder::OptimizationLevel Level) {
+          MPM.addPass(MemorySanitizerPass(Options));
+        }
+      );
 #endif
       OptimizerLastEPCallbacks.push_back(
         [Options](FunctionPassManager &FPM, PassBuilder::OptimizationLevel Level) {
@@ -854,9 +889,11 @@ LLVMRustOptimizeWithNewPassManager(
       );
 #else
 #if LLVM_VERSION_GE(10, 0)
-      PipelineStartEPCallbacks.push_back([](ModulePassManager &MPM) {
-        MPM.addPass(ThreadSanitizerPass());
-      });
+      PipelineStartEPCallbacks.push_back(
+        [](ModulePassManager &MPM, PassBuilder::OptimizationLevel Level) {
+          MPM.addPass(ThreadSanitizerPass());
+        }
+      );
 #endif
       OptimizerLastEPCallbacks.push_back(
         [](FunctionPassManager &FPM, PassBuilder::OptimizationLevel Level) {
@@ -879,9 +916,11 @@ LLVMRustOptimizeWithNewPassManager(
         }
       );
 #else
-      PipelineStartEPCallbacks.push_back([&](ModulePassManager &MPM) {
-        MPM.addPass(RequireAnalysisPass<ASanGlobalsMetadataAnalysis, Module>());
-      });
+      PipelineStartEPCallbacks.push_back(
+        [&](ModulePassManager &MPM, PassBuilder::OptimizationLevel Level) {
+          MPM.addPass(RequireAnalysisPass<ASanGlobalsMetadataAnalysis, Module>());
+        }
+      );
       OptimizerLastEPCallbacks.push_back(
         [SanitizerOptions](FunctionPassManager &FPM, PassBuilder::OptimizationLevel Level) {
           FPM.addPass(AddressSanitizerPass(
@@ -890,7 +929,7 @@ LLVMRustOptimizeWithNewPassManager(
         }
       );
       PipelineStartEPCallbacks.push_back(
-        [SanitizerOptions](ModulePassManager &MPM) {
+        [SanitizerOptions](ModulePassManager &MPM, PassBuilder::OptimizationLevel Level) {
           MPM.addPass(ModuleAddressSanitizerPass(
               /*CompileKernel=*/false, SanitizerOptions->SanitizeAddressRecover));
         }
@@ -907,7 +946,7 @@ LLVMRustOptimizeWithNewPassManager(
       );
 #else
       PipelineStartEPCallbacks.push_back(
-        [SanitizerOptions](ModulePassManager &MPM) {
+        [SanitizerOptions](ModulePassManager &MPM, PassBuilder::OptimizationLevel Level) {
           MPM.addPass(HWAddressSanitizerPass(
               /*CompileKernel=*/false, SanitizerOptions->SanitizeHWAddressRecover));
         }
@@ -917,35 +956,53 @@ LLVMRustOptimizeWithNewPassManager(
   }
 
   ModulePassManager MPM(DebugPassManager);
+  bool NeedThinLTOBufferPasses = UseThinLTOBuffers;
   if (!NoPrepopulatePasses) {
     if (OptLevel == PassBuilder::OptimizationLevel::O0) {
+#if LLVM_VERSION_GE(12, 0)
       for (const auto &C : PipelineStartEPCallbacks)
-        C(MPM);
+        PB.registerPipelineStartEPCallback(C);
+      for (const auto &C : OptimizerLastEPCallbacks)
+        PB.registerOptimizerLastEPCallback(C);
 
-#if LLVM_VERSION_GE(11, 0)
+      // Pass false as we manually schedule ThinLTOBufferPasses below.
+      MPM = PB.buildO0DefaultPipeline(OptLevel, /* PreLinkLTO */ false);
+#else
+      for (const auto &C : PipelineStartEPCallbacks)
+        C(MPM, OptLevel);
+
+# if LLVM_VERSION_GE(11, 0)
       for (const auto &C : OptimizerLastEPCallbacks)
         C(MPM, OptLevel);
-#else
+# else
       if (!OptimizerLastEPCallbacks.empty()) {
         FunctionPassManager FPM(DebugPassManager);
         for (const auto &C : OptimizerLastEPCallbacks)
           C(FPM, OptLevel);
         MPM.addPass(createModuleToFunctionPassAdaptor(std::move(FPM)));
       }
-#endif
+# endif
 
       MPM.addPass(AlwaysInlinerPass(EmitLifetimeMarkers));
 
-#if LLVM_VERSION_GE(10, 0)
+# if LLVM_VERSION_GE(10, 0)
       if (PGOOpt) {
         PB.addPGOInstrPassesForO0(
             MPM, DebugPassManager, PGOOpt->Action == PGOOptions::IRInstr,
             /*IsCS=*/false, PGOOpt->ProfileFile, PGOOpt->ProfileRemappingFile);
       }
+# endif
 #endif
     } else {
+#if LLVM_VERSION_GE(12, 0)
       for (const auto &C : PipelineStartEPCallbacks)
         PB.registerPipelineStartEPCallback(C);
+#else
+      for (const auto &C : PipelineStartEPCallbacks)
+        PB.registerPipelineStartEPCallback([C, OptLevel](ModulePassManager &MPM) {
+          C(MPM, OptLevel);
+        });
+#endif
       if (OptStage != LLVMRustOptStage::PreLinkThinLTO) {
         for (const auto &C : OptimizerLastEPCallbacks)
           PB.registerOptimizerLastEPCallback(C);
@@ -956,7 +1013,17 @@ LLVMRustOptimizeWithNewPassManager(
         MPM = PB.buildPerModuleDefaultPipeline(OptLevel, DebugPassManager);
         break;
       case LLVMRustOptStage::PreLinkThinLTO:
+#if LLVM_VERSION_GE(12, 0)
+        MPM = PB.buildThinLTOPreLinkDefaultPipeline(OptLevel);
+        // The ThinLTOPreLink pipeline already includes ThinLTOBuffer passes. However, callback
+        // passes may still run afterwards. This means we need to run the buffer passes again.
+        // FIXME: In LLVM 13, the ThinLTOPreLink pipeline also runs OptimizerLastEPCallbacks
+        // before the RequiredLTOPreLinkPasses, in which case we can remove these hacks.
+        if (OptimizerLastEPCallbacks.empty())
+          NeedThinLTOBufferPasses = false;
+#else
         MPM = PB.buildThinLTOPreLinkDefaultPipeline(OptLevel, DebugPassManager);
+#endif
 #if LLVM_VERSION_GE(11, 0)
         for (const auto &C : OptimizerLastEPCallbacks)
           C(MPM, OptLevel);
@@ -970,21 +1037,34 @@ LLVMRustOptimizeWithNewPassManager(
 #endif
         break;
       case LLVMRustOptStage::PreLinkFatLTO:
+#if LLVM_VERSION_GE(12, 0)
+        MPM = PB.buildLTOPreLinkDefaultPipeline(OptLevel);
+        NeedThinLTOBufferPasses = false;
+#else
         MPM = PB.buildLTOPreLinkDefaultPipeline(OptLevel, DebugPassManager);
+#endif
         break;
       case LLVMRustOptStage::ThinLTO:
         // FIXME: Does it make sense to pass the ModuleSummaryIndex?
         // It only seems to be needed for C++ specific optimizations.
+#if LLVM_VERSION_GE(12, 0)
+        MPM = PB.buildThinLTODefaultPipeline(OptLevel, nullptr);
+#else
         MPM = PB.buildThinLTODefaultPipeline(OptLevel, DebugPassManager, nullptr);
+#endif
         break;
       case LLVMRustOptStage::FatLTO:
+#if LLVM_VERSION_GE(12, 0)
+        MPM = PB.buildLTODefaultPipeline(OptLevel, nullptr);
+#else
         MPM = PB.buildLTODefaultPipeline(OptLevel, DebugPassManager, nullptr);
+#endif
         break;
       }
     }
   }
 
-  if (UseThinLTOBuffers) {
+  if (NeedThinLTOBufferPasses) {
     MPM.addPass(CanonicalizeAliasesPass());
     MPM.addPass(NameAnonGlobalPass());
   }
diff --git a/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp b/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp
index 45835990cec..a8536595404 100644
--- a/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp
+++ b/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp
@@ -207,6 +207,8 @@ static Attribute::AttrKind fromRust(LLVMRustAttribute Kind) {
     return Attribute::InaccessibleMemOnly;
   case SanitizeHWAddress:
     return Attribute::SanitizeHWAddress;
+  case WillReturn:
+    return Attribute::WillReturn;
   }
   report_fatal_error("bad AttributeKind");
 }
@@ -263,6 +265,17 @@ extern "C" void LLVMRustAddByValCallSiteAttr(LLVMValueRef Instr, unsigned Index,
   Call->addAttribute(Index, Attr);
 }
 
+extern "C" void LLVMRustAddStructRetCallSiteAttr(LLVMValueRef Instr, unsigned Index,
+                                                 LLVMTypeRef Ty) {
+  CallBase *Call = unwrap<CallBase>(Instr);
+#if LLVM_VERSION_GE(12, 0)
+  Attribute Attr = Attribute::getWithStructRetType(Call->getContext(), unwrap(Ty));
+#else
+  Attribute Attr = Attribute::get(Call->getContext(), Attribute::StructRet);
+#endif
+  Call->addAttribute(Index, Attr);
+}
+
 extern "C" void LLVMRustAddFunctionAttribute(LLVMValueRef Fn, unsigned Index,
                                              LLVMRustAttribute RustAttr) {
   Function *A = unwrap<Function>(Fn);
@@ -304,6 +317,17 @@ extern "C" void LLVMRustAddByValAttr(LLVMValueRef Fn, unsigned Index,
   F->addAttribute(Index, Attr);
 }
 
+extern "C" void LLVMRustAddStructRetAttr(LLVMValueRef Fn, unsigned Index,
+                                         LLVMTypeRef Ty) {
+  Function *F = unwrap<Function>(Fn);
+#if LLVM_VERSION_GE(12, 0)
+  Attribute Attr = Attribute::getWithStructRetType(F->getContext(), unwrap(Ty));
+#else
+  Attribute Attr = Attribute::get(F->getContext(), Attribute::StructRet);
+#endif
+  F->addAttribute(Index, Attr);
+}
+
 extern "C" void LLVMRustAddFunctionAttrStringValue(LLVMValueRef Fn,
                                                    unsigned Index,
                                                    const char *Name,
@@ -1007,12 +1031,19 @@ LLVMRustDICompositeTypeReplaceArrays(LLVMRustDIBuilderRef Builder,
 
 extern "C" LLVMMetadataRef
 LLVMRustDIBuilderCreateDebugLocation(unsigned Line, unsigned Column,
-                                     LLVMMetadataRef Scope,
+                                     LLVMMetadataRef ScopeRef,
                                      LLVMMetadataRef InlinedAt) {
-  DebugLoc debug_loc = DebugLoc::get(Line, Column, unwrapDIPtr<MDNode>(Scope),
+#if LLVM_VERSION_GE(12, 0)
+  MDNode *Scope = unwrapDIPtr<MDNode>(ScopeRef);
+  DILocation *Loc = DILocation::get(
+      Scope->getContext(), Line, Column, Scope,
+      unwrapDIPtr<MDNode>(InlinedAt));
+  return wrap(Loc);
+#else
+  DebugLoc debug_loc = DebugLoc::get(Line, Column, unwrapDIPtr<MDNode>(ScopeRef),
                                      unwrapDIPtr<MDNode>(InlinedAt));
-
   return wrap(debug_loc.getAsMDNode());
+#endif
 }
 
 extern "C" int64_t LLVMRustDIBuilderCreateOpDeref() {
@@ -1263,6 +1294,10 @@ extern "C" LLVMTypeKind LLVMRustGetTypeKind(LLVMTypeRef Ty) {
   case Type::BFloatTyID:
     return LLVMBFloatTypeKind;
 #endif
+#if LLVM_VERSION_GE(12, 0)
+  case Type::X86_AMXTyID:
+    return LLVMX86_AMXTypeKind;
+#endif
   }
   report_fatal_error("Unhandled TypeID.");
 }
@@ -1708,11 +1743,23 @@ LLVMRustBuildVectorReduceMax(LLVMBuilderRef B, LLVMValueRef Src, bool IsSigned)
 }
 extern "C" LLVMValueRef
 LLVMRustBuildVectorReduceFMin(LLVMBuilderRef B, LLVMValueRef Src, bool NoNaN) {
-   return wrap(unwrap(B)->CreateFPMinReduce(unwrap(Src), NoNaN));
+#if LLVM_VERSION_GE(12, 0)
+  Instruction *I = unwrap(B)->CreateFPMinReduce(unwrap(Src));
+  I->setHasNoNaNs(NoNaN);
+  return wrap(I);
+#else
+  return wrap(unwrap(B)->CreateFPMinReduce(unwrap(Src), NoNaN));
+#endif
 }
 extern "C" LLVMValueRef
 LLVMRustBuildVectorReduceFMax(LLVMBuilderRef B, LLVMValueRef Src, bool NoNaN) {
+#if LLVM_VERSION_GE(12, 0)
+  Instruction *I = unwrap(B)->CreateFPMaxReduce(unwrap(Src));
+  I->setHasNoNaNs(NoNaN);
+  return wrap(I);
+#else
   return wrap(unwrap(B)->CreateFPMaxReduce(unwrap(Src), NoNaN));
+#endif
 }
 
 extern "C" LLVMValueRef
diff --git a/compiler/rustc_target/src/abi/call/mod.rs b/compiler/rustc_target/src/abi/call/mod.rs
index 9c49922c286..0deb1186b0f 100644
--- a/compiler/rustc_target/src/abi/call/mod.rs
+++ b/compiler/rustc_target/src/abi/call/mod.rs
@@ -603,6 +603,13 @@ impl<'a, Ty> FnAbi<'a, Ty> {
         Ty: TyAndLayoutMethods<'a, C> + Copy,
         C: LayoutOf<Ty = Ty, TyAndLayout = TyAndLayout<'a, Ty>> + HasDataLayout + HasTargetSpec,
     {
+        if abi == spec::abi::Abi::X86Interrupt {
+            if let Some(arg) = self.args.first_mut() {
+                arg.make_indirect_byval();
+            }
+            return Ok(());
+        }
+
         match &cx.target_spec().arch[..] {
             "x86" => {
                 let flavor = if abi == spec::abi::Abi::Fastcall {
diff --git a/compiler/rustc_target/src/spec/powerpc64_unknown_linux_gnu.rs b/compiler/rustc_target/src/spec/powerpc64_unknown_linux_gnu.rs
index 751022c124b..9db880b0e53 100644
--- a/compiler/rustc_target/src/spec/powerpc64_unknown_linux_gnu.rs
+++ b/compiler/rustc_target/src/spec/powerpc64_unknown_linux_gnu.rs
@@ -14,7 +14,7 @@ pub fn target() -> Target {
     Target {
         llvm_target: "powerpc64-unknown-linux-gnu".to_string(),
         pointer_width: 64,
-        data_layout: "E-m:e-i64:64-n32:64".to_string(),
+        data_layout: "E-m:e-i64:64-n32:64-v256:256:256-v512:512:512".to_string(),
         arch: "powerpc64".to_string(),
         options: TargetOptions { endian: Endian::Big, mcount: "_mcount".to_string(), ..base },
     }
diff --git a/compiler/rustc_target/src/spec/powerpc64_unknown_linux_musl.rs b/compiler/rustc_target/src/spec/powerpc64_unknown_linux_musl.rs
index 546dfbab6c7..8767f86b00b 100644
--- a/compiler/rustc_target/src/spec/powerpc64_unknown_linux_musl.rs
+++ b/compiler/rustc_target/src/spec/powerpc64_unknown_linux_musl.rs
@@ -10,7 +10,7 @@ pub fn target() -> Target {
     Target {
         llvm_target: "powerpc64-unknown-linux-musl".to_string(),
         pointer_width: 64,
-        data_layout: "E-m:e-i64:64-n32:64".to_string(),
+        data_layout: "E-m:e-i64:64-n32:64-v256:256:256-v512:512:512".to_string(),
         arch: "powerpc64".to_string(),
         options: TargetOptions { endian: Endian::Big, mcount: "_mcount".to_string(), ..base },
     }
diff --git a/compiler/rustc_target/src/spec/powerpc64_wrs_vxworks.rs b/compiler/rustc_target/src/spec/powerpc64_wrs_vxworks.rs
index bb55872109c..2f28a856247 100644
--- a/compiler/rustc_target/src/spec/powerpc64_wrs_vxworks.rs
+++ b/compiler/rustc_target/src/spec/powerpc64_wrs_vxworks.rs
@@ -10,7 +10,7 @@ pub fn target() -> Target {
     Target {
         llvm_target: "powerpc64-unknown-linux-gnu".to_string(),
         pointer_width: 64,
-        data_layout: "E-m:e-i64:64-n32:64".to_string(),
+        data_layout: "E-m:e-i64:64-n32:64-v256:256:256-v512:512:512".to_string(),
         arch: "powerpc64".to_string(),
         options: TargetOptions { endian: Endian::Big, ..base },
     }
diff --git a/compiler/rustc_target/src/spec/powerpc64le_unknown_linux_gnu.rs b/compiler/rustc_target/src/spec/powerpc64le_unknown_linux_gnu.rs
index 07e0bf81bc7..4cbd9976508 100644
--- a/compiler/rustc_target/src/spec/powerpc64le_unknown_linux_gnu.rs
+++ b/compiler/rustc_target/src/spec/powerpc64le_unknown_linux_gnu.rs
@@ -9,7 +9,7 @@ pub fn target() -> Target {
     Target {
         llvm_target: "powerpc64le-unknown-linux-gnu".to_string(),
         pointer_width: 64,
-        data_layout: "e-m:e-i64:64-n32:64".to_string(),
+        data_layout: "e-m:e-i64:64-n32:64-v256:256:256-v512:512:512".to_string(),
         arch: "powerpc64".to_string(),
         options: TargetOptions { mcount: "_mcount".to_string(), ..base },
     }
diff --git a/compiler/rustc_target/src/spec/powerpc64le_unknown_linux_musl.rs b/compiler/rustc_target/src/spec/powerpc64le_unknown_linux_musl.rs
index 41c78a5f276..efdc9ad7517 100644
--- a/compiler/rustc_target/src/spec/powerpc64le_unknown_linux_musl.rs
+++ b/compiler/rustc_target/src/spec/powerpc64le_unknown_linux_musl.rs
@@ -9,7 +9,7 @@ pub fn target() -> Target {
     Target {
         llvm_target: "powerpc64le-unknown-linux-musl".to_string(),
         pointer_width: 64,
-        data_layout: "e-m:e-i64:64-n32:64".to_string(),
+        data_layout: "e-m:e-i64:64-n32:64-v256:256:256-v512:512:512".to_string(),
         arch: "powerpc64".to_string(),
         options: TargetOptions { mcount: "_mcount".to_string(), ..base },
     }
diff --git a/library/profiler_builtins/build.rs b/library/profiler_builtins/build.rs
index 7d5c601df53..2de6db762b2 100644
--- a/library/profiler_builtins/build.rs
+++ b/library/profiler_builtins/build.rs
@@ -26,6 +26,7 @@ fn main() {
         "InstrProfilingPlatformWindows.c",
         "InstrProfilingUtil.c",
         "InstrProfilingValue.c",
+        "InstrProfilingVersionVar.c",
         "InstrProfilingWriter.c",
         // This file was renamed in LLVM 10.
         "InstrProfilingRuntime.cc",
diff --git a/src/bootstrap/native.rs b/src/bootstrap/native.rs
index b5a8b694c94..fb5127bac54 100644
--- a/src/bootstrap/native.rs
+++ b/src/bootstrap/native.rs
@@ -383,6 +383,8 @@ fn configure_cmake(
             cfg.define("CMAKE_SYSTEM_NAME", "Windows");
         } else if target.contains("haiku") {
             cfg.define("CMAKE_SYSTEM_NAME", "Haiku");
+        } else if target.contains("solaris") || target.contains("illumos") {
+            cfg.define("CMAKE_SYSTEM_NAME", "SunOS");
         }
         // When cross-compiling we should also set CMAKE_SYSTEM_VERSION, but in
         // that case like CMake we cannot easily determine system version either.
diff --git a/src/ci/docker/host-x86_64/arm-android/Dockerfile b/src/ci/docker/host-x86_64/arm-android/Dockerfile
index f675252fb16..43cdbbe92e3 100644
--- a/src/ci/docker/host-x86_64/arm-android/Dockerfile
+++ b/src/ci/docker/host-x86_64/arm-android/Dockerfile
@@ -36,5 +36,8 @@ ENV SCRIPT python3 ../x.py --stage 2 test --host='' --target $TARGETS
 COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh
 
+COPY scripts/cmake.sh /scripts/
+RUN /scripts/cmake.sh
+
 COPY scripts/android-start-emulator.sh /scripts/
 ENTRYPOINT ["/scripts/android-start-emulator.sh"]
diff --git a/src/ci/docker/host-x86_64/dist-aarch64-linux/Dockerfile b/src/ci/docker/host-x86_64/dist-aarch64-linux/Dockerfile
index 95c54ca1abc..e6b6b6e53b9 100644
--- a/src/ci/docker/host-x86_64/dist-aarch64-linux/Dockerfile
+++ b/src/ci/docker/host-x86_64/dist-aarch64-linux/Dockerfile
@@ -24,6 +24,9 @@ USER root
 COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh
 
+COPY scripts/cmake.sh /scripts/
+RUN /scripts/cmake.sh
+
 ENV PATH=$PATH:/x-tools/aarch64-unknown-linux-gnueabi/bin
 
 ENV CC_aarch64_unknown_linux_gnu=aarch64-unknown-linux-gnueabi-gcc \
diff --git a/src/ci/docker/host-x86_64/dist-android/Dockerfile b/src/ci/docker/host-x86_64/dist-android/Dockerfile
index 258dcea06e6..ee727359f39 100644
--- a/src/ci/docker/host-x86_64/dist-android/Dockerfile
+++ b/src/ci/docker/host-x86_64/dist-android/Dockerfile
@@ -36,3 +36,6 @@ ENV SCRIPT python3 ../x.py dist --host='' --target $TARGETS
 
 COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh
+
+COPY scripts/cmake.sh /scripts/
+RUN /scripts/cmake.sh
diff --git a/src/ci/docker/host-x86_64/dist-arm-linux/Dockerfile b/src/ci/docker/host-x86_64/dist-arm-linux/Dockerfile
index 88b13eab2d0..1be3fecd88f 100644
--- a/src/ci/docker/host-x86_64/dist-arm-linux/Dockerfile
+++ b/src/ci/docker/host-x86_64/dist-arm-linux/Dockerfile
@@ -27,6 +27,9 @@ USER root
 COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh
 
+COPY scripts/cmake.sh /scripts/
+RUN /scripts/cmake.sh
+
 ENV PATH=$PATH:/x-tools/arm-unknown-linux-gnueabi/bin
 
 ENV CC_arm_unknown_linux_gnueabi=arm-unknown-linux-gnueabi-gcc \
diff --git a/src/ci/docker/host-x86_64/dist-armhf-linux/Dockerfile b/src/ci/docker/host-x86_64/dist-armhf-linux/Dockerfile
index 977ef08c274..66eb4137a87 100644
--- a/src/ci/docker/host-x86_64/dist-armhf-linux/Dockerfile
+++ b/src/ci/docker/host-x86_64/dist-armhf-linux/Dockerfile
@@ -19,6 +19,9 @@ USER root
 COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh
 
+COPY scripts/cmake.sh /scripts/
+RUN /scripts/cmake.sh
+
 ENV PATH=$PATH:/x-tools/arm-unknown-linux-gnueabihf/bin
 
 ENV CC_arm_unknown_linux_gnueabihf=arm-unknown-linux-gnueabihf-gcc \
diff --git a/src/ci/docker/host-x86_64/dist-armv7-linux/Dockerfile b/src/ci/docker/host-x86_64/dist-armv7-linux/Dockerfile
index 65d713359d9..c13f63911f8 100644
--- a/src/ci/docker/host-x86_64/dist-armv7-linux/Dockerfile
+++ b/src/ci/docker/host-x86_64/dist-armv7-linux/Dockerfile
@@ -19,6 +19,9 @@ USER root
 COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh
 
+COPY scripts/cmake.sh /scripts/
+RUN /scripts/cmake.sh
+
 ENV PATH=$PATH:/x-tools/armv7-unknown-linux-gnueabihf/bin
 
 ENV CC_armv7_unknown_linux_gnueabihf=armv7-unknown-linux-gnueabihf-gcc \
diff --git a/src/ci/docker/host-x86_64/dist-i586-gnu-i586-i686-musl/Dockerfile b/src/ci/docker/host-x86_64/dist-i586-gnu-i586-i686-musl/Dockerfile
index c734202eef6..c98fc7dcfff 100644
--- a/src/ci/docker/host-x86_64/dist-i586-gnu-i586-i686-musl/Dockerfile
+++ b/src/ci/docker/host-x86_64/dist-i586-gnu-i586-i686-musl/Dockerfile
@@ -30,6 +30,9 @@ RUN CC=gcc CFLAGS="-m32 -Wa,-mrelax-relocations=no" \
 COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh
 
+COPY scripts/cmake.sh /scripts/
+RUN /scripts/cmake.sh
+
 ENV RUST_CONFIGURE_ARGS \
       --musl-root-i586=/musl-i586 \
       --musl-root-i686=/musl-i686 \
diff --git a/src/ci/docker/host-x86_64/dist-i686-linux/Dockerfile b/src/ci/docker/host-x86_64/dist-i686-linux/Dockerfile
index 22d7cbb0d14..247b539652b 100644
--- a/src/ci/docker/host-x86_64/dist-i686-linux/Dockerfile
+++ b/src/ci/docker/host-x86_64/dist-i686-linux/Dockerfile
@@ -68,11 +68,13 @@ RUN ./build-binutils.sh
 COPY host-x86_64/dist-x86_64-linux/build-gcc.sh /tmp/
 RUN ./build-gcc.sh && apt-get remove -y gcc g++
 
-# Debian 6 has Python 2.6 by default, but LLVM needs 2.7+
 COPY host-x86_64/dist-x86_64-linux/build-python.sh /tmp/
-RUN ./build-python.sh
+# Build Python 2.7 needed for Clang 10.
+RUN ./build-python.sh 2.7.12
+# Build Python 3 needed for LLVM 12.
+RUN ./build-python.sh 3.9.1
 
-# LLVM needs cmake 3.4.3 or higher, and is planning to raise to 3.13.4.
+# LLVM needs cmake 3.13.4 or higher.
 COPY host-x86_64/dist-x86_64-linux/build-cmake.sh /tmp/
 RUN ./build-cmake.sh
 
diff --git a/src/ci/docker/host-x86_64/dist-mips-linux/Dockerfile b/src/ci/docker/host-x86_64/dist-mips-linux/Dockerfile
index cb5c17c25ab..b0f06569a9c 100644
--- a/src/ci/docker/host-x86_64/dist-mips-linux/Dockerfile
+++ b/src/ci/docker/host-x86_64/dist-mips-linux/Dockerfile
@@ -21,6 +21,9 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
 COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh
 
+COPY scripts/cmake.sh /scripts/
+RUN /scripts/cmake.sh
+
 ENV HOSTS=mips-unknown-linux-gnu
 
 ENV RUST_CONFIGURE_ARGS --enable-extended --disable-docs
diff --git a/src/ci/docker/host-x86_64/dist-mips64-linux/Dockerfile b/src/ci/docker/host-x86_64/dist-mips64-linux/Dockerfile
index 31146e3ead4..245c28e1fa3 100644
--- a/src/ci/docker/host-x86_64/dist-mips64-linux/Dockerfile
+++ b/src/ci/docker/host-x86_64/dist-mips64-linux/Dockerfile
@@ -20,6 +20,9 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
 COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh
 
+COPY scripts/cmake.sh /scripts/
+RUN /scripts/cmake.sh
+
 ENV HOSTS=mips64-unknown-linux-gnuabi64
 
 ENV RUST_CONFIGURE_ARGS --enable-extended --disable-docs
diff --git a/src/ci/docker/host-x86_64/dist-mips64el-linux/Dockerfile b/src/ci/docker/host-x86_64/dist-mips64el-linux/Dockerfile
index dadd50a7e66..03998c8880a 100644
--- a/src/ci/docker/host-x86_64/dist-mips64el-linux/Dockerfile
+++ b/src/ci/docker/host-x86_64/dist-mips64el-linux/Dockerfile
@@ -21,6 +21,9 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
 COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh
 
+COPY scripts/cmake.sh /scripts/
+RUN /scripts/cmake.sh
+
 ENV HOSTS=mips64el-unknown-linux-gnuabi64
 
 ENV RUST_CONFIGURE_ARGS --enable-extended --disable-docs
diff --git a/src/ci/docker/host-x86_64/dist-mipsel-linux/Dockerfile b/src/ci/docker/host-x86_64/dist-mipsel-linux/Dockerfile
index d2d65565b10..58617270621 100644
--- a/src/ci/docker/host-x86_64/dist-mipsel-linux/Dockerfile
+++ b/src/ci/docker/host-x86_64/dist-mipsel-linux/Dockerfile
@@ -20,6 +20,9 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
 COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh
 
+COPY scripts/cmake.sh /scripts/
+RUN /scripts/cmake.sh
+
 ENV HOSTS=mipsel-unknown-linux-gnu
 
 ENV RUST_CONFIGURE_ARGS --enable-extended --disable-docs
diff --git a/src/ci/docker/host-x86_64/dist-powerpc-linux/Dockerfile b/src/ci/docker/host-x86_64/dist-powerpc-linux/Dockerfile
index 651daac8613..ecaa495e97a 100644
--- a/src/ci/docker/host-x86_64/dist-powerpc-linux/Dockerfile
+++ b/src/ci/docker/host-x86_64/dist-powerpc-linux/Dockerfile
@@ -25,6 +25,9 @@ USER root
 COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh
 
+COPY scripts/cmake.sh /scripts/
+RUN /scripts/cmake.sh
+
 ENV PATH=$PATH:/x-tools/powerpc-unknown-linux-gnu/bin
 
 ENV \
diff --git a/src/ci/docker/host-x86_64/dist-powerpc64-linux/Dockerfile b/src/ci/docker/host-x86_64/dist-powerpc64-linux/Dockerfile
index 6ff4d787212..a22d9a7553e 100644
--- a/src/ci/docker/host-x86_64/dist-powerpc64-linux/Dockerfile
+++ b/src/ci/docker/host-x86_64/dist-powerpc64-linux/Dockerfile
@@ -26,6 +26,9 @@ USER root
 COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh
 
+COPY scripts/cmake.sh /scripts/
+RUN /scripts/cmake.sh
+
 ENV PATH=$PATH:/x-tools/powerpc64-unknown-linux-gnu/bin
 
 ENV \
diff --git a/src/ci/docker/host-x86_64/dist-powerpc64le-linux/Dockerfile b/src/ci/docker/host-x86_64/dist-powerpc64le-linux/Dockerfile
index c1a621ff105..5157dd4c79b 100644
--- a/src/ci/docker/host-x86_64/dist-powerpc64le-linux/Dockerfile
+++ b/src/ci/docker/host-x86_64/dist-powerpc64le-linux/Dockerfile
@@ -25,6 +25,9 @@ RUN ./build-powerpc64le-toolchain.sh
 COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh
 
+COPY scripts/cmake.sh /scripts/
+RUN /scripts/cmake.sh
+
 ENV \
     AR_powerpc64le_unknown_linux_gnu=powerpc64le-linux-gnu-ar \
     CC_powerpc64le_unknown_linux_gnu=powerpc64le-linux-gnu-gcc \
diff --git a/src/ci/docker/host-x86_64/dist-riscv64-linux/Dockerfile b/src/ci/docker/host-x86_64/dist-riscv64-linux/Dockerfile
index dff7c475157..80b7793cb7e 100644
--- a/src/ci/docker/host-x86_64/dist-riscv64-linux/Dockerfile
+++ b/src/ci/docker/host-x86_64/dist-riscv64-linux/Dockerfile
@@ -19,6 +19,9 @@ USER root
 COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh
 
+COPY scripts/cmake.sh /scripts/
+RUN /scripts/cmake.sh
+
 ENV PATH=$PATH:/x-tools/riscv64-unknown-linux-gnu/bin
 
 ENV CC_riscv64gc_unknown_linux_gnu=riscv64-unknown-linux-gnu-gcc \
diff --git a/src/ci/docker/host-x86_64/dist-s390x-linux/Dockerfile b/src/ci/docker/host-x86_64/dist-s390x-linux/Dockerfile
index 1b261993cfc..5e626243952 100644
--- a/src/ci/docker/host-x86_64/dist-s390x-linux/Dockerfile
+++ b/src/ci/docker/host-x86_64/dist-s390x-linux/Dockerfile
@@ -25,6 +25,9 @@ USER root
 COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh
 
+COPY scripts/cmake.sh /scripts/
+RUN /scripts/cmake.sh
+
 ENV PATH=$PATH:/x-tools/s390x-ibm-linux-gnu/bin
 
 ENV \
diff --git a/src/ci/docker/host-x86_64/dist-x86_64-freebsd/Dockerfile b/src/ci/docker/host-x86_64/dist-x86_64-freebsd/Dockerfile
index 8413d775ac4..121dd3f455a 100644
--- a/src/ci/docker/host-x86_64/dist-x86_64-freebsd/Dockerfile
+++ b/src/ci/docker/host-x86_64/dist-x86_64-freebsd/Dockerfile
@@ -23,6 +23,9 @@ RUN /tmp/freebsd-toolchain.sh x86_64
 COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh
 
+COPY scripts/cmake.sh /scripts/
+RUN /scripts/cmake.sh
+
 ENV \
     AR_x86_64_unknown_freebsd=x86_64-unknown-freebsd11-ar \
     CC_x86_64_unknown_freebsd=x86_64-unknown-freebsd11-clang \
diff --git a/src/ci/docker/host-x86_64/dist-x86_64-illumos/Dockerfile b/src/ci/docker/host-x86_64/dist-x86_64-illumos/Dockerfile
index 2a0f6a39c57..c2e44ead51e 100644
--- a/src/ci/docker/host-x86_64/dist-x86_64-illumos/Dockerfile
+++ b/src/ci/docker/host-x86_64/dist-x86_64-illumos/Dockerfile
@@ -22,6 +22,9 @@ RUN bash /tmp/illumos-toolchain.sh x86_64 gcc
 COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh
 
+COPY scripts/cmake.sh /scripts/
+RUN /scripts/cmake.sh
+
 ENV \
     AR_x86_64_unknown_illumos=x86_64-illumos-ar \
     CC_x86_64_unknown_illumos=x86_64-illumos-gcc \
diff --git a/src/ci/docker/host-x86_64/dist-x86_64-linux/Dockerfile b/src/ci/docker/host-x86_64/dist-x86_64-linux/Dockerfile
index d1b4bbf7fff..4dd4378f196 100644
--- a/src/ci/docker/host-x86_64/dist-x86_64-linux/Dockerfile
+++ b/src/ci/docker/host-x86_64/dist-x86_64-linux/Dockerfile
@@ -68,11 +68,13 @@ RUN ./build-binutils.sh
 COPY host-x86_64/dist-x86_64-linux/build-gcc.sh /tmp/
 RUN ./build-gcc.sh && apt-get remove -y gcc g++
 
-# Debian 6 has Python 2.6 by default, but LLVM needs 2.7+
 COPY host-x86_64/dist-x86_64-linux/build-python.sh /tmp/
-RUN ./build-python.sh
+# Build Python 2.7 needed for Clang 10.
+RUN ./build-python.sh 2.7.12
+# Build Python 3 needed for LLVM 12.
+RUN ./build-python.sh 3.9.1
 
-# LLVM needs cmake 3.4.3 or higher, and is planning to raise to 3.13.4.
+# LLVM needs cmake 3.13.4 or higher.
 COPY host-x86_64/dist-x86_64-linux/build-cmake.sh /tmp/
 RUN ./build-cmake.sh
 
diff --git a/src/ci/docker/host-x86_64/dist-x86_64-linux/build-python.sh b/src/ci/docker/host-x86_64/dist-x86_64-linux/build-python.sh
index c172b978112..970d67b6db3 100755
--- a/src/ci/docker/host-x86_64/dist-x86_64-linux/build-python.sh
+++ b/src/ci/docker/host-x86_64/dist-x86_64-linux/build-python.sh
@@ -3,7 +3,8 @@
 set -ex
 source shared.sh
 
-curl https://www.python.org/ftp/python/2.7.12/Python-2.7.12.tgz | \
+VERSION=$1
+curl https://www.python.org/ftp/python/$VERSION/Python-$VERSION.tgz | \
   tar xzf -
 
 mkdir python-build
@@ -12,10 +13,10 @@ cd python-build
 # Gotta do some hackery to tell python about our custom OpenSSL build, but other
 # than that fairly normal.
 CFLAGS='-I /rustroot/include' LDFLAGS='-L /rustroot/lib -L /rustroot/lib64' \
-    hide_output ../Python-2.7.12/configure --prefix=/rustroot
+    hide_output ../Python-$VERSION/configure --prefix=/rustroot
 hide_output make -j10
 hide_output make install
 
 cd ..
 rm -rf python-build
-rm -rf Python-2.7.12
+rm -rf Python-$VERSION
diff --git a/src/ci/docker/host-x86_64/dist-x86_64-musl/Dockerfile b/src/ci/docker/host-x86_64/dist-x86_64-musl/Dockerfile
index 904ee64db3b..08f07eb8284 100644
--- a/src/ci/docker/host-x86_64/dist-x86_64-musl/Dockerfile
+++ b/src/ci/docker/host-x86_64/dist-x86_64-musl/Dockerfile
@@ -20,6 +20,10 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
 
 WORKDIR /build/
 
+# Build cmake before musl toolchain, as we replace the compiler during that step.
+COPY scripts/cmake.sh /scripts/
+RUN /scripts/cmake.sh
+
 COPY scripts/musl-toolchain.sh /build/
 # We need to mitigate rust-lang/rust#34978 when compiling musl itself as well
 RUN CFLAGS="-Wa,-mrelax-relocations=no -Wa,--compress-debug-sections=none -Wl,--compress-debug-sections=none" \
diff --git a/src/ci/docker/host-x86_64/dist-x86_64-netbsd/Dockerfile b/src/ci/docker/host-x86_64/dist-x86_64-netbsd/Dockerfile
index f3f7255f154..92bdc9811fd 100644
--- a/src/ci/docker/host-x86_64/dist-x86_64-netbsd/Dockerfile
+++ b/src/ci/docker/host-x86_64/dist-x86_64-netbsd/Dockerfile
@@ -9,6 +9,9 @@ RUN /tmp/build-netbsd-toolchain.sh
 COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh
 
+COPY scripts/cmake.sh /scripts/
+RUN /scripts/cmake.sh
+
 ENV PATH=$PATH:/x-tools/x86_64-unknown-netbsd/bin
 
 ENV \
diff --git a/src/ci/docker/host-x86_64/i686-gnu-nopt/Dockerfile b/src/ci/docker/host-x86_64/i686-gnu-nopt/Dockerfile
index 0e28ea9668f..0182ebb8b59 100644
--- a/src/ci/docker/host-x86_64/i686-gnu-nopt/Dockerfile
+++ b/src/ci/docker/host-x86_64/i686-gnu-nopt/Dockerfile
@@ -20,6 +20,9 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
 COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh
 
+COPY scripts/cmake.sh /scripts/
+RUN /scripts/cmake.sh
+
 RUN mkdir -p /config
 RUN echo "[rust]" > /config/nopt-std-config.toml
 RUN echo "optimize = false" >> /config/nopt-std-config.toml
diff --git a/src/ci/docker/host-x86_64/i686-gnu/Dockerfile b/src/ci/docker/host-x86_64/i686-gnu/Dockerfile
index 195601755f3..feaab819bdd 100644
--- a/src/ci/docker/host-x86_64/i686-gnu/Dockerfile
+++ b/src/ci/docker/host-x86_64/i686-gnu/Dockerfile
@@ -20,6 +20,9 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
 COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh
 
+COPY scripts/cmake.sh /scripts/
+RUN /scripts/cmake.sh
+
 ENV RUST_CONFIGURE_ARGS --build=i686-unknown-linux-gnu
 # Exclude some tests that are unlikely to be platform specific, to speed up
 # this slow job.
diff --git a/src/ci/docker/host-x86_64/x86_64-gnu-aux/Dockerfile b/src/ci/docker/host-x86_64/x86_64-gnu-aux/Dockerfile
index a5bedadc05b..00ad7b0a710 100644
--- a/src/ci/docker/host-x86_64/x86_64-gnu-aux/Dockerfile
+++ b/src/ci/docker/host-x86_64/x86_64-gnu-aux/Dockerfile
@@ -42,5 +42,8 @@ RUN npm install browser-ui-test -g --unsafe-perm=true
 COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh
 
+COPY scripts/cmake.sh /scripts/
+RUN /scripts/cmake.sh
+
 ENV RUST_CONFIGURE_ARGS --build=x86_64-unknown-linux-gnu
 ENV RUST_CHECK_TARGET check-aux-and-gui
diff --git a/src/ci/docker/host-x86_64/x86_64-gnu-distcheck/Dockerfile b/src/ci/docker/host-x86_64/x86_64-gnu-distcheck/Dockerfile
index 5faa0ccab56..09d9cda02bd 100644
--- a/src/ci/docker/host-x86_64/x86_64-gnu-distcheck/Dockerfile
+++ b/src/ci/docker/host-x86_64/x86_64-gnu-distcheck/Dockerfile
@@ -19,6 +19,9 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
 COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh
 
+COPY scripts/cmake.sh /scripts/
+RUN /scripts/cmake.sh
+
 ENV RUST_CONFIGURE_ARGS --build=x86_64-unknown-linux-gnu --set rust.ignore-git=false
 ENV SCRIPT python3 ../x.py --stage 2 test distcheck
 ENV DIST_SRC 1
diff --git a/src/ci/docker/host-x86_64/x86_64-gnu-tools/Dockerfile b/src/ci/docker/host-x86_64/x86_64-gnu-tools/Dockerfile
index 89171a6f215..d4838c0d6f8 100644
--- a/src/ci/docker/host-x86_64/x86_64-gnu-tools/Dockerfile
+++ b/src/ci/docker/host-x86_64/x86_64-gnu-tools/Dockerfile
@@ -18,6 +18,9 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
 COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh
 
+COPY scripts/cmake.sh /scripts/
+RUN /scripts/cmake.sh
+
 COPY host-x86_64/x86_64-gnu-tools/checktools.sh /tmp/
 
 ENV RUST_CONFIGURE_ARGS \
diff --git a/src/ci/docker/scripts/cmake.sh b/src/ci/docker/scripts/cmake.sh
new file mode 100755
index 00000000000..70096173403
--- /dev/null
+++ b/src/ci/docker/scripts/cmake.sh
@@ -0,0 +1,34 @@
+#!/bin/bash
+set -ex
+
+hide_output() {
+  set +x
+  on_err="
+echo ERROR: An error was encountered with the build.
+cat /tmp/build.log
+exit 1
+"
+  trap "$on_err" ERR
+  bash -c "while true; do sleep 30; echo \$(date) - building ...; done" &
+  PING_LOOP_PID=$!
+  "$@" &> /tmp/build.log
+  trap - ERR
+  kill $PING_LOOP_PID
+  rm /tmp/build.log
+  set -x
+}
+
+# LLVM 12 requires CMake 3.13.4 or higher.
+# This script is not necessary for images using Ubuntu 20.04 or newer.
+CMAKE=3.13.4
+curl -L https://github.com/Kitware/CMake/releases/download/v$CMAKE/cmake-$CMAKE.tar.gz | tar xzf -
+
+mkdir cmake-build
+cd cmake-build
+hide_output ../cmake-$CMAKE/configure
+hide_output make -j$(nproc)
+hide_output make install
+
+cd ..
+rm -rf cmake-build
+rm -rf cmake-$CMAKE
diff --git a/src/llvm-project b/src/llvm-project
-Subproject 96ae8953e4938d39c4173dd189f268459fff8c0
+Subproject 40618a2340ac2939b3dc320a9fe1133fa5caa34
diff --git a/src/test/assembly/asm/riscv-types.rs b/src/test/assembly/asm/riscv-types.rs
index 67dda1024fc..47518cdcf16 100644
--- a/src/test/assembly/asm/riscv-types.rs
+++ b/src/test/assembly/asm/riscv-types.rs
@@ -5,6 +5,7 @@
 //[riscv32] compile-flags: --target riscv32imac-unknown-none-elf
 // compile-flags: -C target-feature=+d
 // needs-llvm-components: riscv
+// min-system-llvm-version: 12.0
 
 #![feature(no_core, lang_items, rustc_attrs)]
 #![crate_type = "rlib"]
@@ -99,45 +100,45 @@ macro_rules! check_reg {
 
 // CHECK-LABEL: reg_i8:
 // CHECK: #APP
-// CHECK: add {{[a-z0-9]+}}, zero, {{[a-z0-9]+}}
+// CHECK: mv {{[a-z0-9]+}}, {{[a-z0-9]+}}
 // CHECK: #NO_APP
 check!(reg_i8 i8 reg "mv");
 
 // CHECK-LABEL: reg_i16:
 // CHECK: #APP
-// CHECK: add {{[a-z0-9]+}}, zero, {{[a-z0-9]+}}
+// CHECK: mv {{[a-z0-9]+}}, {{[a-z0-9]+}}
 // CHECK: #NO_APP
 check!(reg_i16 i16 reg "mv");
 
 // CHECK-LABEL: reg_i32:
 // CHECK: #APP
-// CHECK: add {{[a-z0-9]+}}, zero, {{[a-z0-9]+}}
+// CHECK: mv {{[a-z0-9]+}}, {{[a-z0-9]+}}
 // CHECK: #NO_APP
 check!(reg_i32 i32 reg "mv");
 
 // CHECK-LABEL: reg_f32:
 // CHECK: #APP
-// CHECK: add {{[a-z0-9]+}}, zero, {{[a-z0-9]+}}
+// CHECK: mv {{[a-z0-9]+}}, {{[a-z0-9]+}}
 // CHECK: #NO_APP
 check!(reg_f32 f32 reg "mv");
 
 // riscv64-LABEL: reg_i64:
 // riscv64: #APP
-// riscv64: add {{[a-z0-9]+}}, zero, {{[a-z0-9]+}}
+// riscv64: mv {{[a-z0-9]+}}, {{[a-z0-9]+}}
 // riscv64: #NO_APP
 #[cfg(riscv64)]
 check!(reg_i64 i64 reg "mv");
 
 // riscv64-LABEL: reg_f64:
 // riscv64: #APP
-// riscv64: add {{[a-z0-9]+}}, zero, {{[a-z0-9]+}}
+// riscv64: mv {{[a-z0-9]+}}, {{[a-z0-9]+}}
 // riscv64: #NO_APP
 #[cfg(riscv64)]
 check!(reg_f64 f64 reg "mv");
 
 // CHECK-LABEL: reg_ptr:
 // CHECK: #APP
-// CHECK: add {{[a-z0-9]+}}, zero, {{[a-z0-9]+}}
+// CHECK: mv {{[a-z0-9]+}}, {{[a-z0-9]+}}
 // CHECK: #NO_APP
 check!(reg_ptr ptr reg "mv");
 
@@ -155,45 +156,45 @@ check!(freg_f64 f64 freg "fmv.d");
 
 // CHECK-LABEL: a0_i8:
 // CHECK: #APP
-// CHECK: add a0, zero, a0
+// CHECK: mv a0, a0
 // CHECK: #NO_APP
 check_reg!(a0_i8 i8 "a0" "mv");
 
 // CHECK-LABEL: a0_i16:
 // CHECK: #APP
-// CHECK: add a0, zero, a0
+// CHECK: mv a0, a0
 // CHECK: #NO_APP
 check_reg!(a0_i16 i16 "a0" "mv");
 
 // CHECK-LABEL: a0_i32:
 // CHECK: #APP
-// CHECK: add a0, zero, a0
+// CHECK: mv a0, a0
 // CHECK: #NO_APP
 check_reg!(a0_i32 i32 "a0" "mv");
 
 // CHECK-LABEL: a0_f32:
 // CHECK: #APP
-// CHECK: add a0, zero, a0
+// CHECK: mv a0, a0
 // CHECK: #NO_APP
 check_reg!(a0_f32 f32 "a0" "mv");
 
 // riscv64-LABEL: a0_i64:
 // riscv64: #APP
-// riscv64: add a0, zero, a0
+// riscv64: mv a0, a0
 // riscv64: #NO_APP
 #[cfg(riscv64)]
 check_reg!(a0_i64 i64 "a0" "mv");
 
 // riscv64-LABEL: a0_f64:
 // riscv64: #APP
-// riscv64: add a0, zero, a0
+// riscv64: mv a0, a0
 // riscv64: #NO_APP
 #[cfg(riscv64)]
 check_reg!(a0_f64 f64 "a0" "mv");
 
 // CHECK-LABEL: a0_ptr:
 // CHECK: #APP
-// CHECK: add a0, zero, a0
+// CHECK: mv a0, a0
 // CHECK: #NO_APP
 check_reg!(a0_ptr ptr "a0" "mv");
 
diff --git a/src/test/codegen/function-arguments.rs b/src/test/codegen/function-arguments.rs
index 3511c7c5185..a1da4faf5d8 100644
--- a/src/test/codegen/function-arguments.rs
+++ b/src/test/codegen/function-arguments.rs
@@ -1,5 +1,6 @@
 // compile-flags: -C no-prepopulate-passes
 // ignore-tidy-linelength
+// min-system-llvm-version: 12.0
 
 #![crate_type = "lib"]
 #![feature(rustc_attrs)]
@@ -73,7 +74,7 @@ pub fn _box(x: Box<i32>) -> Box<i32> {
   x
 }
 
-// CHECK: @struct_return(%S* noalias nocapture sret dereferenceable(32){{( %0)?}})
+// CHECK: @struct_return(%S* noalias nocapture sret(%S) dereferenceable(32){{( %0)?}})
 #[no_mangle]
 pub fn struct_return() -> S {
   S {
diff --git a/src/test/codegen/packed.rs b/src/test/codegen/packed.rs
index f3f5202206c..c31e8457dcd 100644
--- a/src/test/codegen/packed.rs
+++ b/src/test/codegen/packed.rs
@@ -52,7 +52,7 @@ pub struct BigPacked2 {
 #[no_mangle]
 pub fn call_pkd1(f: fn() -> Array) -> BigPacked1 {
 // CHECK: [[ALLOCA:%[_a-z0-9]+]] = alloca %Array
-// CHECK: call void %{{.*}}(%Array* noalias nocapture sret dereferenceable(32) [[ALLOCA]])
+// CHECK: call void %{{.*}}(%Array* noalias nocapture sret{{.*}} dereferenceable(32) [[ALLOCA]])
 // CHECK: call void @llvm.memcpy.{{.*}}(i8* align 1 %{{.*}}, i8* align 4 %{{.*}}, i{{[0-9]+}} 32, i1 false)
     // check that calls whose destination is a field of a packed struct
     // go through an alloca rather than calling the function with an
@@ -64,7 +64,7 @@ pub fn call_pkd1(f: fn() -> Array) -> BigPacked1 {
 #[no_mangle]
 pub fn call_pkd2(f: fn() -> Array) -> BigPacked2 {
 // CHECK: [[ALLOCA:%[_a-z0-9]+]] = alloca %Array
-// CHECK: call void %{{.*}}(%Array* noalias nocapture sret dereferenceable(32) [[ALLOCA]])
+// CHECK: call void %{{.*}}(%Array* noalias nocapture sret{{.*}} dereferenceable(32) [[ALLOCA]])
 // CHECK: call void @llvm.memcpy.{{.*}}(i8* align 2 %{{.*}}, i8* align 4 %{{.*}}, i{{[0-9]+}} 32, i1 false)
     // check that calls whose destination is a field of a packed struct
     // go through an alloca rather than calling the function with an
diff --git a/src/test/codegen/repr-transparent-aggregates-1.rs b/src/test/codegen/repr-transparent-aggregates-1.rs
index 2b8d3c8bc1d..847b94fac78 100644
--- a/src/test/codegen/repr-transparent-aggregates-1.rs
+++ b/src/test/codegen/repr-transparent-aggregates-1.rs
@@ -1,7 +1,7 @@
 // compile-flags: -C no-prepopulate-passes
 // ignore-tidy-linelength
 
-// min-system-llvm-version: 9.0
+// min-system-llvm-version: 12.0
 // ignore-arm
 // ignore-aarch64
 // ignore-mips
@@ -34,19 +34,19 @@ pub enum TeBigS {
     Variant(BigS),
 }
 
-// CHECK: define void @test_BigS(%BigS* [[BIGS_RET_ATTRS:.*]], %BigS* [[BIGS_ARG_ATTRS1:.*]] byval(%BigS) [[BIGS_ARG_ATTRS2:.*]])
+// CHECK: define void @test_BigS(%BigS* [[BIGS_RET_ATTRS1:.*]] sret(%BigS) [[BIGS_RET_ATTRS2:.*]], %BigS* [[BIGS_ARG_ATTRS1:.*]] byval(%BigS) [[BIGS_ARG_ATTRS2:.*]])
 #[no_mangle]
 pub extern "C" fn test_BigS(_: BigS) -> BigS { loop {} }
 
-// CHECK: define void @test_TsBigS(%TsBigS* [[BIGS_RET_ATTRS]], %TsBigS* [[BIGS_ARG_ATTRS1]] byval(%TsBigS) [[BIGS_ARG_ATTRS2:.*]])
+// CHECK: define void @test_TsBigS(%TsBigS* [[BIGS_RET_ATTRS1]] sret(%TsBigS) [[BIGS_RET_ATTRS2]], %TsBigS* [[BIGS_ARG_ATTRS1]] byval(%TsBigS) [[BIGS_ARG_ATTRS2:.*]])
 #[no_mangle]
 pub extern "C" fn test_TsBigS(_: TsBigS) -> TsBigS { loop {} }
 
-// CHECK: define void @test_TuBigS(%TuBigS* [[BIGS_RET_ATTRS]], %TuBigS* [[BIGS_ARG_ATTRS1]] byval(%TuBigS) [[BIGS_ARG_ATTRS2:.*]])
+// CHECK: define void @test_TuBigS(%TuBigS* [[BIGS_RET_ATTRS1]] sret(%TuBigS) [[BIGS_RET_ATTRS2]], %TuBigS* [[BIGS_ARG_ATTRS1]] byval(%TuBigS) [[BIGS_ARG_ATTRS2:.*]])
 #[no_mangle]
 pub extern "C" fn test_TuBigS(_: TuBigS) -> TuBigS { loop {} }
 
-// CHECK: define void @test_TeBigS(%"TeBigS::Variant"* [[BIGS_RET_ATTRS]], %"TeBigS::Variant"* [[BIGS_ARG_ATTRS1]] byval(%"TeBigS::Variant") [[BIGS_ARG_ATTRS2]])
+// CHECK: define void @test_TeBigS(%"TeBigS::Variant"* [[BIGS_RET_ATTRS1]] sret(%"TeBigS::Variant") [[BIGS_RET_ATTRS2]], %"TeBigS::Variant"* [[BIGS_ARG_ATTRS1]] byval(%"TeBigS::Variant") [[BIGS_ARG_ATTRS2]])
 #[no_mangle]
 pub extern "C" fn test_TeBigS(_: TeBigS) -> TeBigS { loop {} }
 
@@ -70,18 +70,18 @@ pub enum TeBigU {
     Variant(BigU),
 }
 
-// CHECK: define void @test_BigU(%BigU* [[BIGU_RET_ATTRS:.*]], %BigU* [[BIGU_ARG_ATTRS1:.*]] byval(%BigU) [[BIGU_ARG_ATTRS2:.*]])
+// CHECK: define void @test_BigU(%BigU* [[BIGU_RET_ATTRS1:.*]] sret(%BigU) [[BIGU_RET_ATTRS2:.*]], %BigU* [[BIGU_ARG_ATTRS1:.*]] byval(%BigU) [[BIGU_ARG_ATTRS2:.*]])
 #[no_mangle]
 pub extern "C" fn test_BigU(_: BigU) -> BigU { loop {} }
 
-// CHECK: define void @test_TsBigU(%TsBigU* [[BIGU_RET_ATTRS:.*]], %TsBigU* [[BIGU_ARG_ATTRS1]] byval(%TsBigU) [[BIGU_ARG_ATTRS2]])
+// CHECK: define void @test_TsBigU(%TsBigU* [[BIGU_RET_ATTRS1:.*]] sret(%TsBigU) [[BIGU_RET_ATTRS2:.*]], %TsBigU* [[BIGU_ARG_ATTRS1]] byval(%TsBigU) [[BIGU_ARG_ATTRS2]])
 #[no_mangle]
 pub extern "C" fn test_TsBigU(_: TsBigU) -> TsBigU { loop {} }
 
-// CHECK: define void @test_TuBigU(%TuBigU* [[BIGU_RET_ATTRS]], %TuBigU* [[BIGU_ARG_ATTRS1]] byval(%TuBigU) [[BIGU_ARG_ATTRS2]])
+// CHECK: define void @test_TuBigU(%TuBigU* [[BIGU_RET_ATTRS1]] sret(%TuBigU) [[BIGU_RET_ATTRS2:.*]], %TuBigU* [[BIGU_ARG_ATTRS1]] byval(%TuBigU) [[BIGU_ARG_ATTRS2]])
 #[no_mangle]
 pub extern "C" fn test_TuBigU(_: TuBigU) -> TuBigU { loop {} }
 
-// CHECK: define void @test_TeBigU(%"TeBigU::Variant"* [[BIGU_RET_ATTRS]], %"TeBigU::Variant"* [[BIGU_ARG_ATTRS1]] byval(%"TeBigU::Variant") [[BIGU_ARG_ATTRS2]])
+// CHECK: define void @test_TeBigU(%"TeBigU::Variant"* [[BIGU_RET_ATTRS1]] sret(%"TeBigU::Variant") [[BIGU_RET_ATTRS2:.*]], %"TeBigU::Variant"* [[BIGU_ARG_ATTRS1]] byval(%"TeBigU::Variant") [[BIGU_ARG_ATTRS2]])
 #[no_mangle]
 pub extern "C" fn test_TeBigU(_: TeBigU) -> TeBigU { loop {} }
diff --git a/src/test/codegen/repr-transparent-aggregates-2.rs b/src/test/codegen/repr-transparent-aggregates-2.rs
index 07e5af11f35..1fb12d92bd1 100644
--- a/src/test/codegen/repr-transparent-aggregates-2.rs
+++ b/src/test/codegen/repr-transparent-aggregates-2.rs
@@ -1,5 +1,7 @@
 // compile-flags: -C no-prepopulate-passes
+// ignore-tidy-linelength
 
+// min-system-llvm-version: 12.0
 // ignore-aarch64
 // ignore-emscripten
 // ignore-mips64
@@ -36,19 +38,19 @@ pub enum TeBigS {
     Variant(BigS),
 }
 
-// CHECK: define void @test_BigS(%BigS* [[BIGS_RET_ATTRS:.*]], [16 x i32]
+// CHECK: define void @test_BigS(%BigS* [[BIGS_RET_ATTRS1:.*]] sret(%BigS) [[BIGS_RET_ATTRS2:.*]], [16 x i32]
 #[no_mangle]
 pub extern fn test_BigS(_: BigS) -> BigS { loop {} }
 
-// CHECK: define void @test_TsBigS(%TsBigS* [[BIGS_RET_ATTRS]], [16 x i32]
+// CHECK: define void @test_TsBigS(%TsBigS* [[BIGS_RET_ATTRS1]] sret(%TsBigS) [[BIGS_RET_ATTRS2]], [16 x i32]
 #[no_mangle]
 pub extern fn test_TsBigS(_: TsBigS) -> TsBigS { loop {} }
 
-// CHECK: define void @test_TuBigS(%TuBigS* [[BIGS_RET_ATTRS]], [16 x i32]
+// CHECK: define void @test_TuBigS(%TuBigS* [[BIGS_RET_ATTRS1]] sret(%TuBigS) [[BIGS_RET_ATTRS2]], [16 x i32]
 #[no_mangle]
 pub extern fn test_TuBigS(_: TuBigS) -> TuBigS { loop {} }
 
-// CHECK: define void @test_TeBigS(%"TeBigS::Variant"* [[BIGS_RET_ATTRS]], [16 x i32]
+// CHECK: define void @test_TeBigS(%"TeBigS::Variant"* [[BIGS_RET_ATTRS1]] sret(%"TeBigS::Variant") [[BIGS_RET_ATTRS2]], [16 x i32]
 #[no_mangle]
 pub extern fn test_TeBigS(_: TeBigS) -> TeBigS { loop {} }
 
@@ -72,18 +74,18 @@ pub enum TeBigU {
     Variant(BigU),
 }
 
-// CHECK: define void @test_BigU(%BigU* [[BIGU_RET_ATTRS:.*]], [16 x i32]
+// CHECK: define void @test_BigU(%BigU* [[BIGU_RET_ATTRS1:.*]] sret(%BigU) [[BIGU_RET_ATTRS2:.*]], [16 x i32]
 #[no_mangle]
 pub extern fn test_BigU(_: BigU) -> BigU { loop {} }
 
-// CHECK: define void @test_TsBigU(%TsBigU* [[BIGU_RET_ATTRS:.*]], [16 x i32]
+// CHECK: define void @test_TsBigU(%TsBigU* [[BIGU_RET_ATTRS1]] sret(%TsBigU) [[BIGU_RET_ATTRS2]], [16 x i32]
 #[no_mangle]
 pub extern fn test_TsBigU(_: TsBigU) -> TsBigU { loop {} }
 
-// CHECK: define void @test_TuBigU(%TuBigU* [[BIGU_RET_ATTRS]], [16 x i32]
+// CHECK: define void @test_TuBigU(%TuBigU* [[BIGU_RET_ATTRS1]] sret(%TuBigU) [[BIGU_RET_ATTRS2]], [16 x i32]
 #[no_mangle]
 pub extern fn test_TuBigU(_: TuBigU) -> TuBigU { loop {} }
 
-// CHECK: define void @test_TeBigU(%"TeBigU::Variant"* [[BIGU_RET_ATTRS]], [16 x i32]
+// CHECK: define void @test_TeBigU(%"TeBigU::Variant"* [[BIGU_RET_ATTRS1]] sret(%"TeBigU::Variant") [[BIGU_RET_ATTRS2]], [16 x i32]
 #[no_mangle]
 pub extern fn test_TeBigU(_: TeBigU) -> TeBigU { loop {} }
diff --git a/src/test/codegen/repr-transparent-aggregates-3.rs b/src/test/codegen/repr-transparent-aggregates-3.rs
index e538be68780..3381764bfc8 100644
--- a/src/test/codegen/repr-transparent-aggregates-3.rs
+++ b/src/test/codegen/repr-transparent-aggregates-3.rs
@@ -1,5 +1,7 @@
 // compile-flags: -C no-prepopulate-passes
+// ignore-tidy-linelength
 
+// min-system-llvm-version: 12.0
 // only-mips64
 // See repr-transparent.rs
 
@@ -25,19 +27,19 @@ pub enum TeBigS {
     Variant(BigS),
 }
 
-// CHECK: define void @test_BigS(%BigS* [[BIGS_RET_ATTRS:.*]], [8 x i64]
+// CHECK: define void @test_BigS(%BigS* [[BIGS_RET_ATTRS1:.*]] sret(%BigS) [[BIGS_RET_ATTRS2:.*]], [8 x i64]
 #[no_mangle]
 pub extern fn test_BigS(_: BigS) -> BigS { loop {} }
 
-// CHECK: define void @test_TsBigS(%TsBigS* [[BIGS_RET_ATTRS]], [8 x i64]
+// CHECK: define void @test_TsBigS(%TsBigS* [[BIGS_RET_ATTRS1]] sret(%TsBigS) [[BIGS_RET_ATTRS2]], [8 x i64]
 #[no_mangle]
 pub extern fn test_TsBigS(_: TsBigS) -> TsBigS { loop {} }
 
-// CHECK: define void @test_TuBigS(%TuBigS* [[BIGS_RET_ATTRS]], [8 x i64]
+// CHECK: define void @test_TuBigS(%TuBigS* [[BIGS_RET_ATTRS1]] sret(%TuBigS) [[BIGS_RET_ATTRS2]], [8 x i64]
 #[no_mangle]
 pub extern fn test_TuBigS(_: TuBigS) -> TuBigS { loop {} }
 
-// CHECK: define void @test_TeBigS(%"TeBigS::Variant"* [[BIGS_RET_ATTRS]], [8 x i64]
+// CHECK: define void @test_TeBigS(%"TeBigS::Variant"* [[BIGS_RET_ATTRS1]] sret(%"TeBigS::Variant") [[BIGS_RET_ATTRS2]], [8 x i64]
 #[no_mangle]
 pub extern fn test_TeBigS(_: TeBigS) -> TeBigS { loop {} }
 
@@ -61,18 +63,18 @@ pub enum TeBigU {
     Variant(BigU),
 }
 
-// CHECK: define void @test_BigU(%BigU* [[BIGU_RET_ATTRS:.*]], [8 x i64]
+// CHECK: define void @test_BigU(%BigU* [[BIGU_RET_ATTRS1:.*]] sret(%BigU) [[BIGU_RET_ATTRS2:.*]], [8 x i64]
 #[no_mangle]
 pub extern fn test_BigU(_: BigU) -> BigU { loop {} }
 
-// CHECK: define void @test_TsBigU(%TsBigU* [[BIGU_RET_ATTRS:.*]], [8 x i64]
+// CHECK: define void @test_TsBigU(%TsBigU* [[BIGU_RET_ATTRS1]] sret(%TsBigU) [[BIGU_RET_ATTRS2]], [8 x i64]
 #[no_mangle]
 pub extern fn test_TsBigU(_: TsBigU) -> TsBigU { loop {} }
 
-// CHECK: define void @test_TuBigU(%TuBigU* [[BIGU_RET_ATTRS]], [8 x i64]
+// CHECK: define void @test_TuBigU(%TuBigU* [[BIGU_RET_ATTRS1]] sret(%TuBigU) [[BIGU_RET_ATTRS2]], [8 x i64]
 #[no_mangle]
 pub extern fn test_TuBigU(_: TuBigU) -> TuBigU { loop {} }
 
-// CHECK: define void @test_TeBigU(%"TeBigU::Variant"* [[BIGU_RET_ATTRS]], [8 x i64]
+// CHECK: define void @test_TeBigU(%"TeBigU::Variant"* [[BIGU_RET_ATTRS1]] sret(%"TeBigU::Variant") [[BIGU_RET_ATTRS2]], [8 x i64]
 #[no_mangle]
 pub extern fn test_TeBigU(_: TeBigU) -> TeBigU { loop {} }
diff --git a/src/test/run-make-fulldeps/pgo-use/Makefile b/src/test/run-make-fulldeps/pgo-use/Makefile
index cb5e9e9a455..01bc211df16 100644
--- a/src/test/run-make-fulldeps/pgo-use/Makefile
+++ b/src/test/run-make-fulldeps/pgo-use/Makefile
@@ -12,12 +12,11 @@
 # `else` branch. Accordingly, we expect the function that is never called to
 # be marked as cold.
 #
-# The program is compiled with `-Copt-level=s` because this setting disables
-# LLVM's pre-inlining pass (i.e. a pass that does some inlining before it adds
-# the profiling instrumentation). Disabling this pass leads to rather
-# predictable IR which we need for this test to be stable.
+# Disable the pre-inlining pass (i.e. a pass that does some inlining before
+# it adds the profiling instrumentation). Disabling this pass leads to
+# rather predictable IR which we need for this test to be stable.
 
-COMMON_FLAGS=-Copt-level=s -Ccodegen-units=1
+COMMON_FLAGS=-Copt-level=2 -Ccodegen-units=1 -Cllvm-args=-disable-preinline
 
 # LLVM doesn't support instrumenting binaries that use SEH:
 # https://github.com/rust-lang/rust/issues/61002
diff --git a/src/test/run-make-fulldeps/split-dwarf/Makefile b/src/test/run-make-fulldeps/split-dwarf/Makefile
index e89cc1b2ede..f56b4168b2d 100644
--- a/src/test/run-make-fulldeps/split-dwarf/Makefile
+++ b/src/test/run-make-fulldeps/split-dwarf/Makefile
@@ -4,6 +4,6 @@
 # min-llvm-version: 11.0
 
 all:
-	$(RUSTC) -Z unstable-options -C split-debuginfo=packed foo.rs -g
+	$(RUSTC) -Z unstable-options -C split-debuginfo=packed -C debuginfo=2 foo.rs -g
 	rm $(TMPDIR)/foo.dwp
 	rm $(TMPDIR)/$(call BIN,foo)