Update the minimum external LLVM to 16.

.github/workflows/ci.yml

@@ -56,7 +56,7 @@ jobs:
           - name: mingw-check-tidy
             os: ubuntu-20.04-4core-16gb
             env: {}
-          - name: x86_64-gnu-llvm-15
+          - name: x86_64-gnu-llvm-16
             env:
               ENABLE_GCC_CODEGEN: "1"
             os: ubuntu-20.04-16core-64gb
@@ -302,10 +302,6 @@ jobs:
             env:
               RUST_BACKTRACE: 1
             os: ubuntu-20.04-8core-32gb
-          - name: x86_64-gnu-llvm-15
-            env:
-              RUST_BACKTRACE: 1
-            os: ubuntu-20.04-8core-32gb
           - name: x86_64-gnu-nopt
             os: ubuntu-20.04-4core-16gb
             env: {}

compiler/rustc_codegen_llvm/src/context.rs

@@ -134,18 +134,6 @@ pub unsafe fn create_module<'ll>(
 
     let mut target_data_layout = sess.target.data_layout.to_string();
     let llvm_version = llvm_util::get_version();
-    if llvm_version < (16, 0, 0) {
-        if sess.target.arch == "s390x" {
-            // LLVM 16 data layout changed to always set 64-bit vector alignment,
-            // which is conditional in earlier LLVM versions.
-            // https://reviews.llvm.org/D131158 for the discussion.
-            target_data_layout = target_data_layout.replace("-v128:64", "");
-        } else if sess.target.arch == "riscv64" {
-            // LLVM 16 introduced this change so as to produce more efficient code.
-            // See https://reviews.llvm.org/D116735 for the discussion.
-            target_data_layout = target_data_layout.replace("-n32:64-", "-n64-");
-        }
-    }
     if llvm_version < (17, 0, 0) {
         if sess.target.arch.starts_with("powerpc") {
             // LLVM 17 specifies function pointer alignment for ppc:

compiler/rustc_llvm/llvm-wrapper/LLVMWrapper.h

@@ -42,11 +42,7 @@
 #include "llvm/IR/IRPrintingPasses.h"
 #include "llvm/Linker/Linker.h"
 
-#if LLVM_VERSION_GE(16, 0)
 #include "llvm/TargetParser/Triple.h"
-#else
-#include "llvm/ADT/Triple.h"
-#endif
 
 extern "C" void LLVMRustSetLastError(const char *);
 

compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp

@@ -204,11 +204,7 @@ enum class LLVMRustCodeModel {
   None,
 };
 
-#if LLVM_VERSION_LT(16, 0)
-static Optional<CodeModel::Model>
-#else
 static std::optional<CodeModel::Model>
-#endif
 fromRust(LLVMRustCodeModel Model) {
   switch (Model) {
   case LLVMRustCodeModel::Tiny:
@@ -222,11 +218,7 @@ fromRust(LLVMRustCodeModel Model) {
   case LLVMRustCodeModel::Large:
     return CodeModel::Large;
   case LLVMRustCodeModel::None:
-#if LLVM_VERSION_LT(16, 0)
-    return None;
-#else
     return std::nullopt;
-#endif
   default:
     report_fatal_error("Bad CodeModel.");
   }
@@ -452,15 +444,13 @@ extern "C" LLVMTargetMachineRef LLVMRustCreateTargetMachine(
   if (OutputObjFile) {
       Options.ObjectFilenameForDebug = OutputObjFile;
   }
-#if LLVM_VERSION_GE(16, 0)
   if (!strcmp("zlib", DebugInfoCompression) && llvm::compression::zlib::isAvailable()) {
     Options.CompressDebugSections = DebugCompressionType::Zlib;
   } else if (!strcmp("zstd", DebugInfoCompression) && llvm::compression::zstd::isAvailable()) {
     Options.CompressDebugSections = DebugCompressionType::Zstd;
   } else if (!strcmp("none", DebugInfoCompression)) {
     Options.CompressDebugSections = DebugCompressionType::None;
   }
-#endif
 
   Options.RelaxELFRelocations = RelaxELFRelocations;
   Options.UseInitArray = UseInitArray;
@@ -734,22 +724,14 @@ LLVMRustOptimize(
   bool DebugPassManager = false;
 
   PassInstrumentationCallbacks PIC;
-#if LLVM_VERSION_LT(16, 0)
-  StandardInstrumentations SI(DebugPassManager);
-#else
   StandardInstrumentations SI(TheModule->getContext(), DebugPassManager);
-#endif
   SI.registerCallbacks(PIC);
 
   if (LlvmSelfProfiler){
     LLVMSelfProfileInitializeCallbacks(PIC,LlvmSelfProfiler,BeforePassCallback,AfterPassCallback);
   }
 
-#if LLVM_VERSION_LT(16, 0)
-  Optional<PGOOptions> PGOOpt;
-#else
   std::optional<PGOOptions> PGOOpt;
-#endif
 #if LLVM_VERSION_GE(17, 0)
   auto FS = vfs::getRealFileSystem();
 #endif
@@ -882,12 +864,7 @@ LLVMRustOptimize(
           /*EagerChecks=*/true);
       OptimizerLastEPCallbacks.push_back(
         [Options](ModulePassManager &MPM, OptimizationLevel Level) {
-#if LLVM_VERSION_LT(16, 0)
-          MPM.addPass(ModuleMemorySanitizerPass(Options));
-          MPM.addPass(createModuleToFunctionPassAdaptor(MemorySanitizerPass(Options)));
-#else
           MPM.addPass(MemorySanitizerPass(Options));
-#endif
         }
       );
     }
@@ -912,11 +889,7 @@ LLVMRustOptimize(
             /*UseAfterScope=*/true,
             AsanDetectStackUseAfterReturnMode::Runtime,
           };
-#if LLVM_VERSION_LT(16, 0)
-          MPM.addPass(ModuleAddressSanitizerPass(opts));
-#else
           MPM.addPass(AddressSanitizerPass(opts));
-#endif
         }
       );
     }

compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp

@@ -14,18 +14,13 @@
 #include "llvm/Remarks/RemarkSerializer.h"
 #include "llvm/Remarks/RemarkFormat.h"
 #include "llvm/Support/ToolOutputFile.h"
-#if LLVM_VERSION_GE(16, 0)
 #include "llvm/Support/ModRef.h"
-#endif
 #include "llvm/Object/Archive.h"
 #include "llvm/Object/COFFImportFile.h"
 #include "llvm/Object/ObjectFile.h"
 #include "llvm/Pass.h"
 #include "llvm/Bitcode/BitcodeWriter.h"
 #include "llvm/Support/Signals.h"
-#if LLVM_VERSION_LT(16, 0)
-#include "llvm/ADT/Optional.h"
-#endif
 
 #include <iostream>
 
@@ -347,13 +342,7 @@ extern "C" LLVMAttributeRef LLVMRustCreateUWTableAttr(LLVMContextRef C, bool Asy
 }
 
 extern "C" LLVMAttributeRef LLVMRustCreateAllocSizeAttr(LLVMContextRef C, uint32_t ElementSizeArg) {
-  return wrap(Attribute::getWithAllocSizeArgs(*unwrap(C), ElementSizeArg,
-#if LLVM_VERSION_LT(16, 0)
-                                              None
-#else
-                                              std::nullopt
-#endif
-                                              ));
+  return wrap(Attribute::getWithAllocSizeArgs(*unwrap(C), ElementSizeArg, std::nullopt));
 }
 
 // These values **must** match ffi::AllocKindFlags.
@@ -416,7 +405,6 @@ enum class LLVMRustMemoryEffects {
 
 extern "C" LLVMAttributeRef LLVMRustCreateMemoryEffectsAttr(LLVMContextRef C,
                                                             LLVMRustMemoryEffects Effects) {
-#if LLVM_VERSION_GE(16, 0)
   switch (Effects) {
     case LLVMRustMemoryEffects::None:
       return wrap(Attribute::getWithMemoryEffects(*unwrap(C), MemoryEffects::none()));
@@ -428,18 +416,6 @@ extern "C" LLVMAttributeRef LLVMRustCreateMemoryEffectsAttr(LLVMContextRef C,
     default:
       report_fatal_error("bad MemoryEffects.");
   }
-#else
-  switch (Effects) {
-    case LLVMRustMemoryEffects::None:
-      return wrap(Attribute::get(*unwrap(C), Attribute::ReadNone));
-    case LLVMRustMemoryEffects::ReadOnly:
-      return wrap(Attribute::get(*unwrap(C), Attribute::ReadOnly));
-    case LLVMRustMemoryEffects::InaccessibleMemOnly:
-      return wrap(Attribute::get(*unwrap(C), Attribute::InaccessibleMemOnly));
-    default:
-      report_fatal_error("bad MemoryEffects.");
-  }
-#endif
 }
 
 // Enable a fast-math flag
@@ -726,18 +702,10 @@ enum class LLVMRustChecksumKind {
   SHA256,
 };
 
-#if LLVM_VERSION_LT(16, 0)
-static Optional<DIFile::ChecksumKind> fromRust(LLVMRustChecksumKind Kind) {
-#else
 static std::optional<DIFile::ChecksumKind> fromRust(LLVMRustChecksumKind Kind) {
-#endif
   switch (Kind) {
   case LLVMRustChecksumKind::None:
-#if LLVM_VERSION_LT(16, 0)
-    return None;
-#else
     return std::nullopt;
-#endif
   case LLVMRustChecksumKind::MD5:
     return DIFile::ChecksumKind::CSK_MD5;
   case LLVMRustChecksumKind::SHA1:
@@ -810,17 +778,8 @@ extern "C" LLVMMetadataRef LLVMRustDIBuilderCreateFile(
     const char *Directory, size_t DirectoryLen, LLVMRustChecksumKind CSKind,
     const char *Checksum, size_t ChecksumLen) {
 
-#if LLVM_VERSION_LT(16, 0)
-  Optional<DIFile::ChecksumKind> llvmCSKind = fromRust(CSKind);
-#else
   std::optional<DIFile::ChecksumKind> llvmCSKind = fromRust(CSKind);
-#endif
-
-#if LLVM_VERSION_LT(16, 0)
-  Optional<DIFile::ChecksumInfo<StringRef>> CSInfo{};
-#else
   std::optional<DIFile::ChecksumInfo<StringRef>> CSInfo{};
-#endif
   if (llvmCSKind)
     CSInfo.emplace(*llvmCSKind, StringRef{Checksum, ChecksumLen});
   return wrap(Builder->createFile(StringRef(Filename, FilenameLen),
@@ -2053,17 +2012,9 @@ extern "C" bool LLVMRustIsNonGVFunctionPointerTy(LLVMValueRef V) {
 }
 
 extern "C" bool LLVMRustLLVMHasZlibCompressionForDebugSymbols() {
-#if LLVM_VERSION_GE(16, 0)
   return llvm::compression::zlib::isAvailable();
-#else
-  return false;
-#endif
 }
 
 extern "C" bool LLVMRustLLVMHasZstdCompressionForDebugSymbols() {
-#if LLVM_VERSION_GE(16, 0)
   return llvm::compression::zstd::isAvailable();
-#else
-  return false;
-#endif
 }

compiler/rustc_target/src/spec/mod.rs

@@ -1155,10 +1155,6 @@ pub enum StackProbeType {
 }
 
 impl StackProbeType {
-    // LLVM X86 targets (ix86 and x86_64) can use inline-asm stack probes starting with LLVM 16.
-    // Notable past issues were rust#83139 (fixed in 14) and rust#84667 (fixed in 16).
-    const X86: Self = Self::InlineOrCall { min_llvm_version_for_inline: (16, 0, 0) };
-
     fn from_json(json: &Json) -> Result<Self, String> {
         let object = json.as_object().ok_or_else(|| "expected a JSON object")?;
         let kind = object

compiler/rustc_target/src/spec/targets/i386_apple_ios.rs

@@ -16,7 +16,7 @@ pub fn target() -> Target {
         arch: arch.target_arch(),
         options: TargetOptions {
             max_atomic_width: Some(64),
-            stack_probes: StackProbeType::X86,
+            stack_probes: StackProbeType::Inline,
             ..opts("ios", arch)
         },
     }

compiler/rustc_target/src/spec/targets/i586_pc_nto_qnx700.rs

@@ -16,7 +16,7 @@ pub fn target() -> Target {
                 &["-Vgcc_ntox86_cxx"],
             ),
             env: "nto70".into(),
-            stack_probes: StackProbeType::X86,
+            stack_probes: StackProbeType::Inline,
             ..base::nto_qnx::opts()
         },
     }

compiler/rustc_target/src/spec/targets/i686_apple_darwin.rs

@@ -7,7 +7,7 @@ pub fn target() -> Target {
     let mut base = opts("macos", arch);
     base.max_atomic_width = Some(64);
     base.add_pre_link_args(LinkerFlavor::Darwin(Cc::Yes, Lld::No), &["-m32"]);
-    base.stack_probes = StackProbeType::X86;
+    base.stack_probes = StackProbeType::Inline;
     base.frame_pointer = FramePointer::Always;
 
     Target {

compiler/rustc_target/src/spec/targets/i686_linux_android.rs

@@ -11,7 +11,7 @@ pub fn target() -> Target {
     // https://developer.android.com/ndk/guides/abis.html#x86
     base.cpu = "pentiumpro".into();
     base.features = "+mmx,+sse,+sse2,+sse3,+ssse3".into();
-    base.stack_probes = StackProbeType::X86;
+    base.stack_probes = StackProbeType::Inline;
 
     Target {
         llvm_target: "i686-linux-android".into(),

compiler/rustc_target/src/spec/targets/i686_unknown_freebsd.rs

@@ -5,7 +5,7 @@ pub fn target() -> Target {
     base.cpu = "pentium4".into();
     base.max_atomic_width = Some(64);
     base.add_pre_link_args(LinkerFlavor::Gnu(Cc::Yes, Lld::No), &["-m32", "-Wl,-znotext"]);
-    base.stack_probes = StackProbeType::X86;
+    base.stack_probes = StackProbeType::Inline;
 
     Target {
         llvm_target: "i686-unknown-freebsd".into(),

compiler/rustc_target/src/spec/targets/i686_unknown_haiku.rs

@@ -5,7 +5,7 @@ pub fn target() -> Target {
     base.cpu = "pentium4".into();
     base.max_atomic_width = Some(64);
     base.add_pre_link_args(LinkerFlavor::Gnu(Cc::Yes, Lld::No), &["-m32"]);
-    base.stack_probes = StackProbeType::X86;
+    base.stack_probes = StackProbeType::Inline;
 
     Target {
         llvm_target: "i686-unknown-haiku".into(),

compiler/rustc_target/src/spec/targets/i686_unknown_linux_gnu.rs

@@ -6,7 +6,7 @@ pub fn target() -> Target {
     base.max_atomic_width = Some(64);
     base.supported_sanitizers = SanitizerSet::ADDRESS;
     base.add_pre_link_args(LinkerFlavor::Gnu(Cc::Yes, Lld::No), &["-m32"]);
-    base.stack_probes = StackProbeType::X86;
+    base.stack_probes = StackProbeType::Inline;
 
     Target {
         llvm_target: "i686-unknown-linux-gnu".into(),

compiler/rustc_target/src/spec/targets/i686_unknown_linux_musl.rs

@@ -5,7 +5,7 @@ pub fn target() -> Target {
     base.cpu = "pentium4".into();
     base.max_atomic_width = Some(64);
     base.add_pre_link_args(LinkerFlavor::Gnu(Cc::Yes, Lld::No), &["-m32", "-Wl,-melf_i386"]);
-    base.stack_probes = StackProbeType::X86;
+    base.stack_probes = StackProbeType::Inline;
 
     // The unwinder used by i686-unknown-linux-musl, the LLVM libunwind
     // implementation, apparently relies on frame pointers existing... somehow.

compiler/rustc_target/src/spec/targets/i686_unknown_netbsd.rs

@@ -5,7 +5,7 @@ pub fn target() -> Target {
     base.cpu = "pentium4".into();
     base.max_atomic_width = Some(64);
     base.add_pre_link_args(LinkerFlavor::Gnu(Cc::Yes, Lld::No), &["-m32"]);
-    base.stack_probes = StackProbeType::X86;
+    base.stack_probes = StackProbeType::Inline;
 
     Target {
         llvm_target: "i686-unknown-netbsdelf".into(),

compiler/rustc_target/src/spec/targets/i686_unknown_openbsd.rs

@@ -5,7 +5,7 @@ pub fn target() -> Target {
     base.cpu = "pentium4".into();
     base.max_atomic_width = Some(64);
     base.add_pre_link_args(LinkerFlavor::Gnu(Cc::Yes, Lld::No), &["-m32", "-fuse-ld=lld"]);
-    base.stack_probes = StackProbeType::X86;
+    base.stack_probes = StackProbeType::Inline;
 
     Target {
         llvm_target: "i686-unknown-openbsd".into(),

compiler/rustc_target/src/spec/targets/i686_wrs_vxworks.rs

@@ -5,7 +5,7 @@ pub fn target() -> Target {
     base.cpu = "pentium4".into();
     base.max_atomic_width = Some(64);
     base.add_pre_link_args(LinkerFlavor::Gnu(Cc::Yes, Lld::No), &["-m32"]);
-    base.stack_probes = StackProbeType::X86;
+    base.stack_probes = StackProbeType::Inline;
 
     Target {
         llvm_target: "i686-unknown-linux-gnu".into(),

compiler/rustc_target/src/spec/targets/x86_64_apple_darwin.rs

@@ -8,7 +8,7 @@ pub fn target() -> Target {
     base.max_atomic_width = Some(128); // penryn+ supports cmpxchg16b
     base.frame_pointer = FramePointer::Always;
     base.add_pre_link_args(LinkerFlavor::Darwin(Cc::Yes, Lld::No), &["-m64"]);
-    base.stack_probes = StackProbeType::X86;
+    base.stack_probes = StackProbeType::Inline;
     base.supported_sanitizers =
         SanitizerSet::ADDRESS | SanitizerSet::CFI | SanitizerSet::LEAK | SanitizerSet::THREAD;
 

compiler/rustc_target/src/spec/targets/x86_64_apple_ios.rs

@@ -14,7 +14,7 @@ pub fn target() -> Target {
         arch: arch.target_arch(),
         options: TargetOptions {
             max_atomic_width: Some(128),
-            stack_probes: StackProbeType::X86,
+            stack_probes: StackProbeType::Inline,
             ..base
         },
     }

compiler/rustc_target/src/spec/targets/x86_64_apple_ios_macabi.rs

@@ -17,7 +17,7 @@ pub fn target() -> Target {
         arch: arch.target_arch(),
         options: TargetOptions {
             max_atomic_width: Some(128),
-            stack_probes: StackProbeType::X86,
+            stack_probes: StackProbeType::Inline,
             ..base
         },
     }