[MC] Move CompressDebugSections/RelaxELFRelocations from TargetOptions/MCAsmInfo to MCTargetOptions

The convention is for such MC-specific options to reside in
MCTargetOptions. However, CompressDebugSections/RelaxELFRelocations do
not follow the convention: `CompressDebugSections` is defined in both
TargetOptions and MCAsmInfo and there is forwarding complexity.

Move the option to MCTargetOptions and hereby simplify the code. Rename
the misleading RelaxELFRelocations to X86RelaxRelocations. llvm-mc
-relax-relocations and llc -x86-relax-relocations can now be unified.

Author: MaskRay

clang/lib/CodeGen/BackendUtil.cpp

@@ -356,8 +356,6 @@ static bool initTargetOptions(DiagnosticsEngine &Diags,
       llvm::TargetMachine::parseBinutilsVersion(CodeGenOpts.BinutilsVersion);
   Options.UseInitArray = CodeGenOpts.UseInitArray;
   Options.DisableIntegratedAS = CodeGenOpts.DisableIntegratedAS;
-  Options.CompressDebugSections = CodeGenOpts.getCompressDebugSections();
-  Options.RelaxELFRelocations = CodeGenOpts.RelaxELFRelocations;
 
   // Set EABI version.
   Options.EABIVersion = TargetOpts.EABIVersion;
@@ -460,6 +458,9 @@ static bool initTargetOptions(DiagnosticsEngine &Diags,
   Options.MCOptions.AsmVerbose = CodeGenOpts.AsmVerbose;
   Options.MCOptions.Dwarf64 = CodeGenOpts.Dwarf64;
   Options.MCOptions.PreserveAsmComments = CodeGenOpts.PreserveAsmComments;
+  Options.MCOptions.X86RelaxRelocations = CodeGenOpts.RelaxELFRelocations;
+  Options.MCOptions.CompressDebugSections =
+      CodeGenOpts.getCompressDebugSections();
   Options.MCOptions.ABIName = TargetOpts.ABI;
   for (const auto &Entry : HSOpts.UserEntries)
     if (!Entry.IsFramework &&

clang/tools/driver/cc1as_main.cpp

@@ -428,6 +428,8 @@ static bool ExecuteAssemblerImpl(AssemblerInvocation &Opts,
   MCTargetOptions MCOptions;
   MCOptions.EmitDwarfUnwind = Opts.EmitDwarfUnwind;
   MCOptions.EmitCompactUnwindNonCanonical = Opts.EmitCompactUnwindNonCanonical;
+  MCOptions.X86RelaxRelocations = Opts.RelaxELFRelocations;
+  MCOptions.CompressDebugSections = Opts.CompressDebugSections;
   MCOptions.AsSecureLogFile = Opts.AsSecureLogFile;
 
   std::unique_ptr<MCAsmInfo> MAI(
@@ -436,9 +438,7 @@ static bool ExecuteAssemblerImpl(AssemblerInvocation &Opts,
 
   // Ensure MCAsmInfo initialization occurs before any use, otherwise sections
   // may be created with a combination of default and explicit settings.
-  MAI->setCompressDebugSections(Opts.CompressDebugSections);
 
-  MAI->setRelaxELFRelocations(Opts.RelaxELFRelocations);
 
   bool IsBinary = Opts.OutputType == AssemblerInvocation::FT_Obj;
   if (Opts.OutputPath.empty())

lld/test/ELF/weak-undef-got-pie.s

@@ -1,7 +1,7 @@
 # REQUIRES: x86
 # RUN: llvm-mc -filetype=obj -triple=x86_64 %p/Inputs/dummy-shared.s -o %t1.o
 # RUN: ld.lld %t1.o -shared -o %t1.so
-# RUN: llvm-mc -filetype=obj -relax-relocations=false -triple=x86_64 %s -o %t.o
+# RUN: llvm-mc -filetype=obj -x86-relax-relocations=false -triple=x86_64 %s -o %t.o
 
 # RUN: ld.lld -pie %t.o %t1.so -o %t
 # RUN: llvm-readobj -r %t | FileCheck --check-prefix=RELOCS %s

llvm/include/llvm/CodeGen/CommandFlags.h

@@ -98,8 +98,6 @@ bool getUseCtors();
 
 bool getDisableIntegratedAS();
 
-bool getRelaxELFRelocations();
-
 bool getDataSections();
 std::optional<bool> getExplicitDataSections();
 

llvm/include/llvm/MC/MCAsmInfo.h

@@ -524,17 +524,10 @@ class MCAsmInfo {
   /// Preserve Comments in assembly
   bool PreserveAsmComments;
 
-  /// Compress DWARF debug sections. Defaults to no compression.
-  DebugCompressionType CompressDebugSections = DebugCompressionType::None;
-
   /// True if the integrated assembler should interpret 'a >> b' constant
   /// expressions as logical rather than arithmetic.
   bool UseLogicalShr = true;
 
-  // If true, emit GOTPCRELX/REX_GOTPCRELX instead of GOTPCREL, on
-  // X86_64 ELF.
-  bool RelaxELFRelocations = true;
-
   // If true, then the lexer and expression parser will support %neg(),
   // %hi(), and similar unary operators.
   bool HasMipsExpressions = false;
@@ -875,18 +868,9 @@ class MCAsmInfo {
     PreserveAsmComments = Value;
   }
 
-  DebugCompressionType compressDebugSections() const {
-    return CompressDebugSections;
-  }
-
-  void setCompressDebugSections(DebugCompressionType CompressDebugSections) {
-    this->CompressDebugSections = CompressDebugSections;
-  }
 
   bool shouldUseLogicalShr() const { return UseLogicalShr; }
 
-  bool canRelaxRelocations() const { return RelaxELFRelocations; }
-  void setRelaxELFRelocations(bool V) { RelaxELFRelocations = V; }
   bool hasMipsExpressions() const { return HasMipsExpressions; }
   bool needsFunctionDescriptors() const { return NeedsFunctionDescriptors; }
   bool shouldUseMotorolaIntegers() const { return UseMotorolaIntegers; }

llvm/include/llvm/MC/MCContext.h

@@ -451,6 +451,8 @@ class MCContext {
 
   const MCSubtargetInfo *getSubtargetInfo() const { return MSTI; }
 
+  const MCTargetOptions *getTargetOptions() const { return TargetOptions; }
+
   CodeViewContext &getCVContext();
 
   void setAllowTemporaryLabels(bool Value) { AllowTemporaryLabels = Value; }

llvm/include/llvm/MC/MCTargetOptions.h

@@ -61,6 +61,10 @@ class MCTargetOptions {
 
   bool Dwarf64 : 1;
 
+  // If true, prefer R_X86_64_[REX_]GOTPCRELX to R_X86_64_GOTPCREL on x86-64
+  // ELF.
+  bool X86RelaxRelocations = true;
+
   EmitDwarfUnwindType EmitDwarfUnwind;
 
   int DwarfVersion = 0;
@@ -76,6 +80,9 @@ class MCTargetOptions {
   };
   DwarfDirectory MCUseDwarfDirectory;
 
+  // Whether to compress DWARF debug sections.
+  DebugCompressionType CompressDebugSections = DebugCompressionType::None;
+
   std::string ABIName;
   std::string AssemblyLanguage;
   std::string SplitDwarfFile;

llvm/include/llvm/MC/MCTargetOptionsCommandFlags.h

@@ -49,6 +49,8 @@ bool getNoDeprecatedWarn();
 
 bool getNoTypeCheck();
 
+bool getX86RelaxRelocations();
+
 std::string getABIName();
 
 std::string getAsSecureLogFile();

llvm/include/llvm/Target/TargetOptions.h

@@ -141,18 +141,18 @@ namespace llvm {
           HonorSignDependentRoundingFPMathOption(false), NoZerosInBSS(false),
           GuaranteedTailCallOpt(false), StackSymbolOrdering(true),
           EnableFastISel(false), EnableGlobalISel(false), UseInitArray(false),
-          DisableIntegratedAS(false), RelaxELFRelocations(true),
-          FunctionSections(false), DataSections(false),
-          IgnoreXCOFFVisibility(false), XCOFFTracebackTable(true),
-          UniqueSectionNames(true), UniqueBasicBlockSectionNames(false),
-          TrapUnreachable(false), NoTrapAfterNoreturn(false), TLSSize(0),
-          EmulatedTLS(false), EnableTLSDESC(false), EnableIPRA(false),
-          EmitStackSizeSection(false), EnableMachineOutliner(false),
-          EnableMachineFunctionSplitter(false), SupportsDefaultOutlining(false),
-          EmitAddrsig(false), BBAddrMap(false), EmitCallSiteInfo(false),
-          SupportsDebugEntryValues(false), EnableDebugEntryValues(false),
-          ValueTrackingVariableLocations(false), ForceDwarfFrameSection(false),
-          XRayFunctionIndex(true), DebugStrictDwarf(false), Hotpatch(false),
+          DisableIntegratedAS(false), FunctionSections(false),
+          DataSections(false), IgnoreXCOFFVisibility(false),
+          XCOFFTracebackTable(true), UniqueSectionNames(true),
+          UniqueBasicBlockSectionNames(false), TrapUnreachable(false),
+          NoTrapAfterNoreturn(false), TLSSize(0), EmulatedTLS(false),
+          EnableTLSDESC(false), EnableIPRA(false), EmitStackSizeSection(false),
+          EnableMachineOutliner(false), EnableMachineFunctionSplitter(false),
+          SupportsDefaultOutlining(false), EmitAddrsig(false), BBAddrMap(false),
+          EmitCallSiteInfo(false), SupportsDebugEntryValues(false),
+          EnableDebugEntryValues(false), ValueTrackingVariableLocations(false),
+          ForceDwarfFrameSection(false), XRayFunctionIndex(true),
+          DebugStrictDwarf(false), Hotpatch(false),
           PPCGenScalarMASSEntries(false), JMCInstrument(false),
           EnableCFIFixup(false), MisExpect(false), XCOFFReadOnlyPointers(false),
           FPDenormalMode(DenormalMode::IEEE, DenormalMode::IEEE) {}
@@ -260,11 +260,6 @@ namespace llvm {
     /// Disable the integrated assembler.
     unsigned DisableIntegratedAS : 1;
 
-    /// Compress DWARF debug sections.
-    DebugCompressionType CompressDebugSections = DebugCompressionType::None;
-
-    unsigned RelaxELFRelocations : 1;
-
     /// Emit functions into separate sections.
     unsigned FunctionSections : 1;
 

llvm/lib/CodeGen/CommandFlags.cpp

@@ -85,7 +85,6 @@ CGOPT(bool, StackRealign)
 CGOPT(std::string, TrapFuncName)
 CGOPT(bool, UseCtors)
 CGOPT(bool, DisableIntegratedAS)
-CGOPT(bool, RelaxELFRelocations)
 CGOPT_EXP(bool, DataSections)
 CGOPT_EXP(bool, FunctionSections)
 CGOPT(bool, IgnoreXCOFFVisibility)
@@ -362,13 +361,6 @@ codegen::RegisterCodeGenFlags::RegisterCodeGenFlags() {
                                 cl::init(false));
   CGBINDOPT(UseCtors);
 
-  static cl::opt<bool> RelaxELFRelocations(
-      "x86-relax-relocations",
-      cl::desc(
-          "Emit GOTPCRELX/REX_GOTPCRELX instead of GOTPCREL on x86-64 ELF"),
-      cl::init(true));
-  CGBINDOPT(RelaxELFRelocations);
-
   static cl::opt<bool> DataSections(
       "data-sections", cl::desc("Emit data into separate sections"),
       cl::init(false));
@@ -568,7 +560,6 @@ codegen::InitTargetOptionsFromCodeGenFlags(const Triple &TheTriple) {
   Options.StackSymbolOrdering = getStackSymbolOrdering();
   Options.UseInitArray = !getUseCtors();
   Options.DisableIntegratedAS = getDisableIntegratedAS();
-  Options.RelaxELFRelocations = getRelaxELFRelocations();
   Options.DataSections =
       getExplicitDataSections().value_or(TheTriple.hasDefaultDataSections());
   Options.FunctionSections = getFunctionSections();

llvm/lib/CodeGen/LLVMTargetMachine.cpp

@@ -77,10 +77,6 @@ void LLVMTargetMachine::initAsmInfo() {
 
   TmpAsmInfo->setPreserveAsmComments(Options.MCOptions.PreserveAsmComments);
 
-  TmpAsmInfo->setCompressDebugSections(Options.CompressDebugSections);
-
-  TmpAsmInfo->setRelaxELFRelocations(Options.RelaxELFRelocations);
-
   TmpAsmInfo->setFullRegisterNames(Options.MCOptions.PPCUseFullRegisterNames);
 
   if (Options.ExceptionModel != ExceptionHandling::None)

llvm/lib/LTO/LTO.cpp

@@ -124,9 +124,9 @@ void llvm::computeLTOCacheKey(
   AddString(Conf.CPU);
   // FIXME: Hash more of Options. For now all clients initialize Options from
   // command-line flags (which is unsupported in production), but may set
-  // RelaxELFRelocations. The clang driver can also pass FunctionSections,
+  // X86RelaxRelocations. The clang driver can also pass FunctionSections,
   // DataSections and DebuggerTuning via command line flags.
-  AddUnsigned(Conf.Options.RelaxELFRelocations);
+  AddUnsigned(Conf.Options.MCOptions.X86RelaxRelocations);
   AddUnsigned(Conf.Options.FunctionSections);
   AddUnsigned(Conf.Options.DataSections);
   AddUnsigned((unsigned)Conf.Options.DebuggerTuning);

llvm/lib/MC/ELFObjectWriter.cpp

@@ -875,11 +875,10 @@ void ELFWriter::writeSectionData(const MCAssembler &Asm, MCSection &Sec,
                                  const MCAsmLayout &Layout) {
   MCSectionELF &Section = static_cast<MCSectionELF &>(Sec);
   StringRef SectionName = Section.getName();
-
-  auto &MC = Asm.getContext();
-  const auto &MAI = MC.getAsmInfo();
-
-  const DebugCompressionType CompressionType = MAI->compressDebugSections();
+  auto &Ctx = Asm.getContext();
+  const DebugCompressionType CompressionType =
+      Ctx.getTargetOptions() ? Ctx.getTargetOptions()->CompressDebugSections
+                             : DebugCompressionType::None;
   if (CompressionType == DebugCompressionType::None ||
       !SectionName.starts_with(".debug_")) {
     Asm.writeSectionData(W.OS, &Section, Layout);

llvm/lib/MC/MCTargetOptionsCommandFlags.cpp

@@ -46,6 +46,7 @@ MCOPT(bool, FatalWarnings)
 MCOPT(bool, NoWarn)
 MCOPT(bool, NoDeprecatedWarn)
 MCOPT(bool, NoTypeCheck)
+MCOPT(bool, X86RelaxRelocations)
 MCOPT(std::string, ABIName)
 MCOPT(std::string, AsSecureLogFile)
 
@@ -122,6 +123,13 @@ llvm::mc::RegisterMCTargetOptionsFlags::RegisterMCTargetOptionsFlags() {
       "no-type-check", cl::desc("Suppress type errors (Wasm)"));
   MCBINDOPT(NoTypeCheck);
 
+  static cl::opt<bool> X86RelaxRelocations(
+      "x86-relax-relocations",
+      cl::desc(
+          "Emit GOTPCRELX/REX_GOTPCRELX instead of GOTPCREL on x86-64 ELF"),
+      cl::init(true));
+  MCBINDOPT(X86RelaxRelocations);
+
   static cl::opt<std::string> ABIName(
       "target-abi", cl::Hidden,
       cl::desc("The name of the ABI to be targeted from the backend."),
@@ -148,6 +156,7 @@ MCTargetOptions llvm::mc::InitMCTargetOptionsFromFlags() {
   Options.MCNoWarn = getNoWarn();
   Options.MCNoDeprecatedWarn = getNoDeprecatedWarn();
   Options.MCNoTypeCheck = getNoTypeCheck();
+  Options.X86RelaxRelocations = getX86RelaxRelocations();
   Options.EmitDwarfUnwind = getEmitDwarfUnwind();
   Options.EmitCompactUnwindNonCanonical = getEmitCompactUnwindNonCanonical();
   Options.AsSecureLogFile = getAsSecureLogFile();

llvm/lib/Target/X86/MCTargetDesc/X86ELFObjectWriter.cpp

@@ -207,7 +207,7 @@ static unsigned getRelocType64(MCContext &Ctx, SMLoc Loc,
     // Older versions of ld.bfd/ld.gold/lld
     // do not support GOTPCRELX/REX_GOTPCRELX,
     // and we want to keep back-compatibility.
-    if (!Ctx.getAsmInfo()->canRelaxRelocations())
+    if (!Ctx.getTargetOptions()->X86RelaxRelocations)
       return ELF::R_X86_64_GOTPCREL;
     switch (unsigned(Kind)) {
     default:
@@ -259,7 +259,7 @@ static unsigned getRelocType32(MCContext &Ctx, SMLoc Loc,
       return ELF::R_386_GOTPC;
     // Older versions of ld.bfd/ld.gold/lld do not support R_386_GOT32X and we
     // want to maintain compatibility.
-    if (!Ctx.getAsmInfo()->canRelaxRelocations())
+    if (!Ctx.getTargetOptions()->X86RelaxRelocations)
       return ELF::R_386_GOT32;
 
     return Kind == MCFixupKind(X86::reloc_signed_4byte_relax)

llvm/lib/Target/X86/X86MCInstLower.cpp

@@ -546,13 +546,13 @@ void X86AsmPrinter::LowerTlsAddr(X86MCInstLower &MCInstLowering,
   const MCSymbolRefExpr *Sym = MCSymbolRefExpr::create(
       MCInstLowering.GetSymbolFromOperand(MI.getOperand(3)), SRVK, Ctx);
 
-  // As of binutils 2.32, ld has a bogus TLS relaxation error when the GD/LD
+  // Before binutils 2.41, ld has a bogus TLS relaxation error when the GD/LD
   // code sequence using R_X86_64_GOTPCREL (instead of R_X86_64_GOTPCRELX) is
   // attempted to be relaxed to IE/LE (binutils PR24784). Work around the bug by
   // only using GOT when GOTPCRELX is enabled.
-  // TODO Delete the workaround when GOTPCRELX becomes commonplace.
+  // TODO Delete the workaround when rustc no longer relies on the hack
   bool UseGot = MMI->getModule()->getRtLibUseGOT() &&
-                Ctx.getAsmInfo()->canRelaxRelocations();
+                Ctx.getTargetOptions()->X86RelaxRelocations;
 
   if (Is64Bits) {
     bool NeedsPadding = SRVK == MCSymbolRefExpr::VK_TLSGD;

llvm/test/ExecutionEngine/JITLink/AArch64/ELF_minimal.s

@@ -1,5 +1,5 @@
 # RUN: rm -rf %t && mkdir -p %t
-# RUN: llvm-mc -triple=aarch64-unknown-linux-gnu -relax-relocations=false \
+# RUN: llvm-mc -triple=aarch64-unknown-linux-gnu -x86-relax-relocations=false \
 # RUN:   -position-independent -filetype=obj -o %t/elf_minimal.o %s
 # RUN: llvm-jitlink -noexec %t/elf_minimal.o
 

llvm/test/ExecutionEngine/JITLink/AArch64/ELF_relocations.s

@@ -1,5 +1,5 @@
 # RUN: rm -rf %t && mkdir -p %t
-# RUN: llvm-mc -triple=aarch64-unknown-linux-gnu -relax-relocations=false \
+# RUN: llvm-mc -triple=aarch64-unknown-linux-gnu -x86-relax-relocations=false \
 # RUN:   -position-independent -filetype=obj -o %t/elf_reloc.o %s
 # RUN: llvm-jitlink -noexec \
 # RUN:              -abs external_data=0xdeadbeef \

llvm/test/ExecutionEngine/JITLink/x86-64/COFF_small_pic_relocations.s

@@ -1,5 +1,5 @@
 # RUN: rm -rf %t && mkdir -p %t
-# RUN: llvm-mc -triple=x86_64-windows-msvc -relax-relocations=false \
+# RUN: llvm-mc -triple=x86_64-windows-msvc -x86-relax-relocations=false \
 # RUN:   -position-independent -filetype=obj -o %t/coff_sm_reloc.o %s
 # RUN: llvm-jitlink -noexec \
 # RUN:              -slab-allocate 100Kb -slab-address 0xfff00000 -slab-page-size 4096 \

llvm/test/ExecutionEngine/JITLink/x86-64/ELF_common_var.s

@@ -1,5 +1,5 @@
 # RUN: rm -rf %t && mkdir -p %t
-# RUN: llvm-mc -triple=x86_64-unknown-linux -relax-relocations=false -position-independent -filetype=obj -o %t/elf_common.o %s
+# RUN: llvm-mc -triple=x86_64-unknown-linux -x86-relax-relocations=false -position-independent -filetype=obj -o %t/elf_common.o %s
 # RUN: llvm-jitlink -entry=load_common -noexec -check %s %t/elf_common.o
 #
 # Check that common variable GOT entry is synthesized correctly.

llvm/test/MC/ELF/got-relaxed-i386.s

@@ -1,5 +1,5 @@
 // RUN: llvm-mc -filetype=obj -triple i386-pc-linux %s -o - | llvm-readobj -r - | FileCheck %s
-// RUN: llvm-mc -filetype=obj -relax-relocations=false -triple i386-pc-linux %s -o - | llvm-readobj -r - | FileCheck --check-prefix=OLD %s
+// RUN: llvm-mc -filetype=obj -x86-relax-relocations=false -triple i386-pc-linux %s -o - | llvm-readobj -r - | FileCheck --check-prefix=OLD %s
 
         movl mov@GOT(%ebx), %eax
         mull mul@GOT(%ebx)

llvm/test/MC/ELF/relocation-386.s

@@ -1,5 +1,5 @@
-// RUN: llvm-mc -filetype=obj -triple i386-pc-linux-gnu %s -relax-relocations=false -o - | llvm-readobj -r  - | FileCheck  %s --check-prefix=CHECK --check-prefix=I386
-// RUN: llvm-mc -filetype=obj -triple i386-pc-elfiamcu %s -relax-relocations=false  -o - | llvm-readobj -r  - | FileCheck  %s --check-prefix=CHECK --check-prefix=IAMCU
+// RUN: llvm-mc -filetype=obj -triple i386-pc-linux-gnu %s -x86-relax-relocations=false -o - | llvm-readobj -r  - | FileCheck  %s --check-prefix=CHECK --check-prefix=I386
+// RUN: llvm-mc -filetype=obj -triple i386-pc-elfiamcu %s -x86-relax-relocations=false  -o - | llvm-readobj -r  - | FileCheck  %s --check-prefix=CHECK --check-prefix=IAMCU
 // RUN: not llvm-mc -filetype=obj -triple=i686 --defsym ERR=1 %s -o /dev/null 2>&1 | FileCheck %s --check-prefix=ERR --implicit-check-not=error:
 
 // Test that we produce the correct relocation types and that the relocations

llvm/test/MC/X86/gotpcrelx.s

@@ -1,6 +1,6 @@
 # RUN: llvm-mc -filetype=obj -triple=x86_64 %s -o %t.o
 # RUN: llvm-readobj -r %t.o | FileCheck %s --check-prefixes=CHECK,COMMON
-# RUN: llvm-mc -filetype=obj -triple=x86_64 -relax-relocations=false %s -o %t1.o
+# RUN: llvm-mc -filetype=obj -triple=x86_64 -x86-relax-relocations=false %s -o %t1.o
 # RUN: llvm-readobj -r %t1.o | FileCheck %s --check-prefixes=NORELAX,COMMON
 
 # COMMON:     Relocations [

llvm/tools/gold/gold-plugin.cpp

@@ -857,7 +857,7 @@ static std::unique_ptr<LTO> createLTO(IndexWriteCallback OnIndexWrite,
 
   // Disable the new X86 relax relocations since gold might not support them.
   // FIXME: Check the gold version or add a new option to enable them.
-  Conf.Options.RelaxELFRelocations = false;
+  Conf.Options.MCOptions.X86RelaxRelocations = false;
 
   // Toggle function/data sections.
   if (!codegen::getExplicitFunctionSections())