[ARM] Move MCStreamer::emitThumbFunc to ARMTargetStreamer

MCStreamer should not declare arch-specific functions. Such functions
should go to MCTargetStreamer.

Move MCMachOStreamer::emitThumbFunc to ARMTargetMachOStreamer, which is
a new subclass of ARMTargetStreamer. (The new class is just placed in
ARMMachObjectWriter.cpp. The conventional split like
ARMELFObjectWriter.cpp/ARMELFObjectWriter.cpp is overkill.)

`emitCFILabel`, called by ARMWinCOFFStreamer.cpp, has to be made public.

Pull Request: llvm#126199

llvm/include/llvm/MC/MCELFStreamer.h

@@ -54,7 +54,6 @@ class MCELFStreamer : public MCObjectStreamer {
   void emitLabelAtPos(MCSymbol *Symbol, SMLoc Loc, MCDataFragment &F,
                       uint64_t Offset) override;
   void emitAssemblerFlag(MCAssemblerFlag Flag) override;
-  void emitThumbFunc(MCSymbol *Func) override;
   void emitWeakReference(MCSymbol *Alias, const MCSymbol *Symbol) override;
   bool emitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute) override;
   void emitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) override;

llvm/include/llvm/MC/MCObjectStreamer.h

@@ -63,7 +63,6 @@ class MCObjectStreamer : public MCStreamer {
   virtual void emitInstToData(const MCInst &Inst, const MCSubtargetInfo&) = 0;
   void emitCFIStartProcImpl(MCDwarfFrameInfo &Frame) override;
   void emitCFIEndProcImpl(MCDwarfFrameInfo &Frame) override;
-  MCSymbol *emitCFILabel() override;
   void emitInstructionImpl(const MCInst &Inst, const MCSubtargetInfo &STI);
   void resolvePendingFixups();
 
@@ -81,6 +80,7 @@ class MCObjectStreamer : public MCStreamer {
   bool isIntegratedAssemblerRequired() const override { return true; }
 
   void emitFrames(MCAsmBackend *MAB);
+  MCSymbol *emitCFILabel() override;
   void emitCFISections(bool EH, bool Debug) override;
 
   void insert(MCFragment *F) {

llvm/include/llvm/MC/MCStreamer.h

@@ -168,6 +168,8 @@ class ARMTargetStreamer : public MCTargetStreamer {
 
   virtual void annotateTLSDescriptorSequence(const MCSymbolRefExpr *SRE);
 
+  // Note in the output that the specified \p Symbol is a Thumb mode function.
+  virtual void emitThumbFunc(MCSymbol *Symbol);
   virtual void emitThumbSet(MCSymbol *Symbol, const MCExpr *Value);
 
   void emitConstantPools() override;
@@ -501,10 +503,6 @@ class MCStreamer {
                             const Triple *DarwinTargetVariantTriple,
                             const VersionTuple &DarwinTargetVariantSDKVersion);
 
-  /// Note in the output that the specified \p Func is a Thumb mode
-  /// function (ARM target only).
-  virtual void emitThumbFunc(MCSymbol *Func);
-
   /// Emit an assignment of \p Value to \p Symbol.
   ///
   /// This corresponds to an assembler statement such as:

llvm/include/llvm/MC/MCWasmStreamer.h

@@ -45,7 +45,6 @@ class MCWasmStreamer : public MCObjectStreamer {
   void emitLabelAtPos(MCSymbol *Symbol, SMLoc Loc, MCDataFragment &F,
                       uint64_t Offset) override;
   void emitAssemblerFlag(MCAssemblerFlag Flag) override;
-  void emitThumbFunc(MCSymbol *Func) override;
   void emitWeakReference(MCSymbol *Alias, const MCSymbol *Symbol) override;
   bool emitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute) override;
   void emitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) override;

llvm/include/llvm/MC/MCWinCOFFStreamer.h

@@ -46,7 +46,6 @@ class MCWinCOFFStreamer : public MCObjectStreamer {
   void changeSection(MCSection *Section, uint32_t Subsection = 0) override;
   void emitLabel(MCSymbol *Symbol, SMLoc Loc = SMLoc()) override;
   void emitAssemblerFlag(MCAssemblerFlag Flag) override;
-  void emitThumbFunc(MCSymbol *Func) override;
   bool emitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute) override;
   void emitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) override;
   void beginCOFFSymbolDef(MCSymbol const *Symbol) override;

llvm/lib/MC/MCAsmStreamer.cpp

@@ -191,7 +191,6 @@ class MCAsmStreamer final : public MCStreamer {
   void emitDarwinTargetVariantBuildVersion(unsigned Platform, unsigned Major,
                                            unsigned Minor, unsigned Update,
                                            VersionTuple SDKVersion) override;
-  void emitThumbFunc(MCSymbol *Func) override;
 
   void emitAssignment(MCSymbol *Symbol, const MCExpr *Value) override;
   void emitConditionalAssignment(MCSymbol *Symbol,
@@ -697,18 +696,6 @@ void MCAsmStreamer::emitDarwinTargetVariantBuildVersion(
   emitBuildVersion(Platform, Major, Minor, Update, SDKVersion);
 }
 
-void MCAsmStreamer::emitThumbFunc(MCSymbol *Func) {
-  // This needs to emit to a temporary string to get properly quoted
-  // MCSymbols when they have spaces in them.
-  OS << "\t.thumb_func";
-  // Only Mach-O hasSubsectionsViaSymbols()
-  if (MAI->hasSubsectionsViaSymbols()) {
-    OS << '\t';
-    Func->print(OS, MAI);
-  }
-  EmitEOL();
-}
-
 void MCAsmStreamer::emitAssignment(MCSymbol *Symbol, const MCExpr *Value) {
   // Do not emit a .set on inlined target assignments.
   bool EmitSet = true;

llvm/lib/MC/MCELFStreamer.cpp

@@ -616,10 +616,6 @@ void MCELFStreamer::finishImpl() {
   this->MCObjectStreamer::finishImpl();
 }
 
-void MCELFStreamer::emitThumbFunc(MCSymbol *Func) {
-  llvm_unreachable("Generic ELF doesn't support this directive");
-}
-
 void MCELFStreamer::emitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {
   llvm_unreachable("ELF doesn't support this directive");
 }

llvm/lib/MC/MCMachOStreamer.cpp

@@ -99,7 +99,6 @@ class MCMachOStreamer : public MCObjectStreamer {
   void emitDarwinTargetVariantBuildVersion(unsigned Platform, unsigned Major,
                                            unsigned Minor, unsigned Update,
                                            VersionTuple SDKVersion) override;
-  void emitThumbFunc(MCSymbol *Func) override;
   bool emitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute) override;
   void emitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) override;
   void emitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
@@ -269,13 +268,6 @@ void MCMachOStreamer::emitDarwinTargetVariantBuildVersion(
                                            Minor, Update, SDKVersion);
 }
 
-void MCMachOStreamer::emitThumbFunc(MCSymbol *Symbol) {
-  // Remember that the function is a thumb function. Fixup and relocation
-  // values will need adjusted.
-  getAssembler().setIsThumbFunc(Symbol);
-  cast<MCSymbolMachO>(Symbol)->setThumbFunc();
-}
-
 bool MCMachOStreamer::emitSymbolAttribute(MCSymbol *Sym,
                                           MCSymbolAttr Attribute) {
   MCSymbolMachO *Symbol = cast<MCSymbolMachO>(Sym);

llvm/lib/MC/MCStreamer.cpp

@@ -1229,7 +1229,6 @@ void MCStreamer::emitAbsoluteSymbolDiffAsULEB128(const MCSymbol *Hi,
 }
 
 void MCStreamer::emitAssemblerFlag(MCAssemblerFlag Flag) {}
-void MCStreamer::emitThumbFunc(MCSymbol *Func) {}
 void MCStreamer::emitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {}
 void MCStreamer::beginCOFFSymbolDef(const MCSymbol *Symbol) {
   llvm_unreachable("this directive only supported on COFF targets");

llvm/lib/MC/MCWasmStreamer.cpp

@@ -238,10 +238,6 @@ void MCWasmStreamer::fixSymbolsInTLSFixups(const MCExpr *expr) {
   }
 }
 
-void MCWasmStreamer::emitThumbFunc(MCSymbol *Func) {
-  llvm_unreachable("Generic Wasm doesn't support this directive");
-}
-
 void MCWasmStreamer::emitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {
   llvm_unreachable("Wasm doesn't support this directive");
 }

llvm/lib/MC/MCWinCOFFStreamer.cpp

@@ -208,10 +208,6 @@ void MCWinCOFFStreamer::emitAssemblerFlag(MCAssemblerFlag Flag) {
   }
 }
 
-void MCWinCOFFStreamer::emitThumbFunc(MCSymbol *Func) {
-  llvm_unreachable("not implemented");
-}
-
 bool MCWinCOFFStreamer::emitSymbolAttribute(MCSymbol *S,
                                             MCSymbolAttr Attribute) {
   auto *Symbol = cast<MCSymbolCOFF>(S);

llvm/lib/Target/ARM/ARMAsmPrinter.cpp

@@ -63,9 +63,11 @@ void ARMAsmPrinter::emitFunctionBodyEnd() {
 }
 
 void ARMAsmPrinter::emitFunctionEntryLabel() {
+  auto &TS =
+      static_cast<ARMTargetStreamer &>(*OutStreamer->getTargetStreamer());
   if (AFI->isThumbFunction()) {
     OutStreamer->emitAssemblerFlag(MCAF_Code16);
-    OutStreamer->emitThumbFunc(CurrentFnSym);
+    TS.emitThumbFunc(CurrentFnSym);
   } else {
     OutStreamer->emitAssemblerFlag(MCAF_Code32);
   }

llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp

@@ -11712,7 +11712,7 @@ void ARMAsmParser::doBeforeLabelEmit(MCSymbol *Symbol, SMLoc IDLoc) {
 
 void ARMAsmParser::onLabelParsed(MCSymbol *Symbol) {
   if (NextSymbolIsThumb) {
-    getParser().getStreamer().emitThumbFunc(Symbol);
+    getTargetStreamer().emitThumbFunc(Symbol);
     NextSymbolIsThumb = false;
   }
 }
@@ -11732,7 +11732,7 @@ bool ARMAsmParser::parseDirectiveThumbFunc(SMLoc L) {
         Parser.getTok().is(AsmToken::String)) {
       MCSymbol *Func = getParser().getContext().getOrCreateSymbol(
           Parser.getTok().getIdentifier());
-      getParser().getStreamer().emitThumbFunc(Func);
+      getTargetStreamer().emitThumbFunc(Func);
       Parser.Lex();
       if (parseEOL())
         return true;

llvm/lib/Target/ARM/MCTargetDesc/ARMELFStreamer.cpp

@@ -100,6 +100,7 @@ class ARMTargetAsmStreamer : public ARMTargetStreamer {
   void finishAttributeSection() override;
 
   void annotateTLSDescriptorSequence(const MCSymbolRefExpr *SRE) override;
+  void emitThumbFunc(MCSymbol *Symbol) override;
   void emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) override;
 
   void emitARMWinCFIAllocStack(unsigned Size, bool Wide) override;
@@ -260,6 +261,17 @@ void ARMTargetAsmStreamer::annotateTLSDescriptorSequence(
   OS << "\t.tlsdescseq\t" << S->getSymbol().getName() << "\n";
 }
 
+void ARMTargetAsmStreamer::emitThumbFunc(MCSymbol *Symbol) {
+  const MCAsmInfo *MAI = Streamer.getContext().getAsmInfo();
+  OS << "\t.thumb_func";
+  // Only Mach-O hasSubsectionsViaSymbols()
+  if (MAI->hasSubsectionsViaSymbols()) {
+    OS << '\t';
+    Symbol->print(OS, MAI);
+  }
+  OS << '\n';
+}
+
 void ARMTargetAsmStreamer::emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) {
   const MCAsmInfo *MAI = Streamer.getContext().getAsmInfo();
 
@@ -422,6 +434,7 @@ class ARMTargetELFStreamer : public ARMTargetStreamer {
   void emitLabel(MCSymbol *Symbol) override;
 
   void annotateTLSDescriptorSequence(const MCSymbolRefExpr *SRE) override;
+  void emitThumbFunc(MCSymbol *Symbol) override;
   void emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) override;
 
   // Reset state between object emissions
@@ -686,11 +699,6 @@ class ARMELFStreamer : public MCELFStreamer {
     Symbol->setBinding(ELF::STB_LOCAL);
   }
 
-  void emitThumbFunc(MCSymbol *Func) override {
-    getAssembler().setIsThumbFunc(Func);
-    emitSymbolAttribute(Func, MCSA_ELF_TypeFunction);
-  }
-
   // Helper functions for ARM exception handling directives
   void EHReset();
 
@@ -1089,14 +1097,19 @@ void ARMTargetELFStreamer::emitLabel(MCSymbol *Symbol) {
   Streamer.getAssembler().registerSymbol(*Symbol);
   unsigned Type = cast<MCSymbolELF>(Symbol)->getType();
   if (Type == ELF::STT_FUNC || Type == ELF::STT_GNU_IFUNC)
-    Streamer.emitThumbFunc(Symbol);
+    emitThumbFunc(Symbol);
 }
 
 void ARMTargetELFStreamer::annotateTLSDescriptorSequence(
     const MCSymbolRefExpr *S) {
   getStreamer().EmitFixup(S, FK_Data_4);
 }
 
+void ARMTargetELFStreamer::emitThumbFunc(MCSymbol *Symbol) {
+  getStreamer().getAssembler().setIsThumbFunc(Symbol);
+  getStreamer().emitSymbolAttribute(Symbol, MCSA_ELF_TypeFunction);
+}
+
 void ARMTargetELFStreamer::emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) {
   if (const MCSymbolRefExpr *SRE = dyn_cast<MCSymbolRefExpr>(Value)) {
     const MCSymbol &Sym = SRE->getSymbol();
@@ -1106,7 +1119,7 @@ void ARMTargetELFStreamer::emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) {
     }
   }
 
-  getStreamer().emitThumbFunc(Symbol);
+  emitThumbFunc(Symbol);
   getStreamer().emitAssignment(Symbol, Value);
 }
 

llvm/lib/Target/ARM/MCTargetDesc/ARMMCTargetDesc.h

@@ -71,6 +71,7 @@ MCTargetStreamer *createARMTargetAsmStreamer(MCStreamer &S,
 MCTargetStreamer *createARMObjectTargetStreamer(MCStreamer &S,
                                                 const MCSubtargetInfo &STI);
 MCTargetStreamer *createARMObjectTargetELFStreamer(MCStreamer &S);
+MCTargetStreamer *createARMObjectTargetMachOStreamer(MCStreamer &S);
 MCTargetStreamer *createARMObjectTargetWinCOFFStreamer(MCStreamer &S);
 
 MCCodeEmitter *createARMLEMCCodeEmitter(const MCInstrInfo &MCII,

llvm/lib/Target/ARM/MCTargetDesc/ARMMachObjectWriter.cpp

@@ -16,8 +16,11 @@
 #include "llvm/MC/MCExpr.h"
 #include "llvm/MC/MCFixup.h"
 #include "llvm/MC/MCMachObjectWriter.h"
+#include "llvm/MC/MCObjectStreamer.h"
 #include "llvm/MC/MCSection.h"
+#include "llvm/MC/MCSymbolMachO.h"
 #include "llvm/MC/MCValue.h"
+#include "llvm/Support/Casting.h"
 #include "llvm/Support/ErrorHandling.h"
 
 using namespace llvm;
@@ -489,3 +492,23 @@ llvm::createARMMachObjectWriter(bool Is64Bit, uint32_t CPUType,
                                 uint32_t CPUSubtype) {
   return std::make_unique<ARMMachObjectWriter>(Is64Bit, CPUType, CPUSubtype);
 }
+
+namespace {
+class ARMTargetMachOStreamer : public ARMTargetStreamer {
+public:
+  ARMTargetMachOStreamer(MCStreamer &S) : ARMTargetStreamer(S) {}
+  MCObjectStreamer &getStreamer() {
+    return static_cast<MCObjectStreamer &>(Streamer);
+  }
+  void emitThumbFunc(MCSymbol *Symbol) override {
+    // Remember that the function is a thumb function. Fixup and relocation
+    // values will need adjusted.
+    getStreamer().getAssembler().setIsThumbFunc(Symbol);
+    cast<MCSymbolMachO>(Symbol)->setThumbFunc();
+  }
+};
+} // namespace
+
+MCTargetStreamer *llvm::createARMObjectTargetMachOStreamer(MCStreamer &S) {
+  return new ARMTargetMachOStreamer(S);
+}

llvm/lib/Target/ARM/MCTargetDesc/ARMTargetStreamer.cpp

@@ -115,6 +115,7 @@ void ARMTargetStreamer::emitFPU(ARM::FPUKind FPU) {}
 void ARMTargetStreamer::finishAttributeSection() {}
 void ARMTargetStreamer::annotateTLSDescriptorSequence(
     const MCSymbolRefExpr *SRE) {}
+void ARMTargetStreamer::emitThumbFunc(MCSymbol *Symbol) {}
 void ARMTargetStreamer::emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) {}
 
 void ARMTargetStreamer::emitARMWinCFIAllocStack(unsigned Size, bool Wide) {}
@@ -329,5 +330,7 @@ llvm::createARMObjectTargetStreamer(MCStreamer &S, const MCSubtargetInfo &STI) {
     return createARMObjectTargetELFStreamer(S);
   if (TT.isOSBinFormatCOFF())
     return createARMObjectTargetWinCOFFStreamer(S);
+  if (TT.isOSBinFormatMachO())
+    return createARMObjectTargetMachOStreamer(S);
   return new ARMTargetStreamer(S);
 }

llvm/lib/Target/ARM/MCTargetDesc/ARMWinCOFFStreamer.cpp

@@ -31,7 +31,6 @@ class ARMWinCOFFStreamer : public MCWinCOFFStreamer {
   void emitWindowsUnwindTables() override;
   void emitWindowsUnwindTables(WinEH::FrameInfo *Frame) override;
 
-  void emitThumbFunc(MCSymbol *Symbol) override;
   void finishImpl() override;
 };
 
@@ -54,10 +53,6 @@ void ARMWinCOFFStreamer::emitWindowsUnwindTables() {
   EHStreamer.Emit(*this);
 }
 
-void ARMWinCOFFStreamer::emitThumbFunc(MCSymbol *Symbol) {
-  getAssembler().setIsThumbFunc(Symbol);
-}
-
 void ARMWinCOFFStreamer::finishImpl() {
   emitFrames(nullptr);
   emitWindowsUnwindTables();
@@ -80,6 +75,11 @@ class ARMTargetWinCOFFStreamer : public llvm::ARMTargetStreamer {
 public:
   ARMTargetWinCOFFStreamer(llvm::MCStreamer &S) : ARMTargetStreamer(S) {}
 
+  ARMWinCOFFStreamer &getStreamer() {
+    return static_cast<ARMWinCOFFStreamer &>(Streamer);
+  }
+  void emitThumbFunc(MCSymbol *Symbol) override;
+
   // The unwind codes on ARM Windows are documented at
   // https://docs.microsoft.com/en-us/cpp/build/arm-exception-handling
   void emitARMWinCFIAllocStack(unsigned Size, bool Wide) override;
@@ -97,6 +97,10 @@ class ARMTargetWinCOFFStreamer : public llvm::ARMTargetStreamer {
   void emitARMWinUnwindCode(unsigned UnwindCode, int Reg, int Offset);
 };
 
+void ARMTargetWinCOFFStreamer::emitThumbFunc(MCSymbol *Symbol) {
+  getStreamer().getAssembler().setIsThumbFunc(Symbol);
+}
+
 // Helper function to common out unwind code setup for those codes that can
 // belong to both prolog and epilog.
 void ARMTargetWinCOFFStreamer::emitARMWinUnwindCode(unsigned UnwindCode,