Print a=b as an assignment.

In assembly the expression a=b is parsed as an assignment, so it should be
printed as one.

This remove a truly horrible hack for producing a label with "a=.". It would
be used by codegen but would never be reached by the asm parser. Sorry I
missed this when it was first committed.

llvm-svn: 211639

include/llvm/MC/MCAsmInfo.h

@@ -116,8 +116,8 @@ protected:
   /// This is appended to emitted labels.  Defaults to ":"
   const char *LabelSuffix;
 
-  /// This is appended to emitted labels.  Defaults to ":"
-  const char *DebugLabelSuffix;
+  // Print the EH begin symbol with an assignment. Defaults to false.
+  bool UseAssignmentForEHBegin;
 
   /// This prefix is used for globals like constant pool entries that are
   /// completely private to the .s file and should not have names in the .o
@@ -415,7 +415,7 @@ public:
   const char *getCommentString() const { return CommentString; }
   const char *getLabelSuffix() const { return LabelSuffix; }
 
-  const char *getDebugLabelSuffix() const { return DebugLabelSuffix; }
+  bool useAssignmentForEHBegin() const { return UseAssignmentForEHBegin; }
   const char *getPrivateGlobalPrefix() const { return PrivateGlobalPrefix; }
   bool hasLinkerPrivateGlobalPrefix() const {
     return LinkerPrivateGlobalPrefix[0] != '\0';

include/llvm/MC/MCELFStreamer.h

@@ -48,7 +48,6 @@ public:
   void ChangeSection(const MCSection *Section,
                      const MCExpr *Subsection) override;
   void EmitLabel(MCSymbol *Symbol) override;
-  void EmitDebugLabel(MCSymbol *Symbol) override;
   void EmitAssemblerFlag(MCAssemblerFlag Flag) override;
   void EmitThumbFunc(MCSymbol *Func) override;
   void EmitWeakReference(MCSymbol *Alias, const MCSymbol *Symbol) override;

include/llvm/MC/MCObjectStreamer.h

@@ -87,7 +87,6 @@ public:
   /// @{
 
   void EmitLabel(MCSymbol *Symbol) override;
-  void EmitDebugLabel(MCSymbol *Symbol) override;
   void EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) override;
   void EmitValueImpl(const MCExpr *Value, unsigned Size,
                      const SMLoc &Loc = SMLoc()) override;

include/llvm/MC/MCStreamer.h

@@ -393,8 +393,6 @@ public:
   // add the section we're emitting it to later.
   virtual void EmitLabel(MCSymbol *Symbol);
 
-  virtual void EmitDebugLabel(MCSymbol *Symbol);
-
   virtual void EmitEHSymAttributes(const MCSymbol *Symbol, MCSymbol *EHSymbol);
 
   /// EmitAssemblerFlag - Note in the output the specified @p Flag.

include/llvm/MC/MCWinCOFFStreamer.h

@@ -35,7 +35,6 @@ public:
 
   void InitSections() override;
   void EmitLabel(MCSymbol *Symbol) override;
-  void EmitDebugLabel(MCSymbol *Symbol) override;
   void EmitAssemblerFlag(MCAssemblerFlag Flag) override;
   void EmitThumbFunc(MCSymbol *Func) override;
   bool EmitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute) override;

lib/CodeGen/AsmPrinter/DwarfCFIException.cpp

@@ -112,9 +112,17 @@ void DwarfCFIException::beginFunction(const MachineFunction *MF) {
       TLOF.getCFIPersonalitySymbol(Per, *Asm->Mang, Asm->TM, MMI);
   Asm->OutStreamer.EmitCFIPersonality(Sym, PerEncoding);
 
-  Asm->OutStreamer.EmitDebugLabel
-    (Asm->GetTempSymbol("eh_func_begin",
-                        Asm->getFunctionNumber()));
+  MCSymbol *EHBegin =
+      Asm->GetTempSymbol("eh_func_begin", Asm->getFunctionNumber());
+  if (Asm->MAI->useAssignmentForEHBegin()) {
+    MCContext &Ctx = Asm->OutContext;
+    MCSymbol *CurPos = Ctx.CreateTempSymbol();
+    Asm->OutStreamer.EmitLabel(CurPos);
+    Asm->OutStreamer.EmitAssignment(EHBegin,
+                                    MCSymbolRefExpr::Create(CurPos, Ctx));
+  } else {
+    Asm->OutStreamer.EmitLabel(EHBegin);
+  }
 
   // Provide LSDA information.
   if (!shouldEmitLSDA)

lib/LTO/LTOModule.cpp

@@ -656,9 +656,6 @@ namespace {
       Symbol->setSection(*getCurrentSection().first);
       markDefined(*Symbol);
     }
-    void EmitDebugLabel(MCSymbol *Symbol) override {
-      EmitLabel(Symbol);
-    }
     void EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) override {
       // FIXME: should we handle aliases?
       markDefined(*Symbol);

lib/MC/MCAsmInfo.cpp

@@ -39,7 +39,7 @@ MCAsmInfo::MCAsmInfo() {
   SeparatorString = ";";
   CommentString = "#";
   LabelSuffix = ":";
-  DebugLabelSuffix = ":";
+  UseAssignmentForEHBegin = false;
   PrivateGlobalPrefix = "L";
   LinkerPrivateGlobalPrefix = "";
   InlineAsmStart = "APP";

lib/MC/MCAsmStreamer.cpp

@@ -120,7 +120,6 @@ public:
 
   void EmitLOHDirective(MCLOHType Kind, const MCLOHArgs &Args) override;
   void EmitLabel(MCSymbol *Symbol) override;
-  void EmitDebugLabel(MCSymbol *Symbol) override;
 
   void EmitAssemblerFlag(MCAssemblerFlag Flag) override;
   void EmitLinkerOptions(ArrayRef<std::string> Options) override;
@@ -334,14 +333,6 @@ void MCAsmStreamer::EmitLOHDirective(MCLOHType Kind, const MCLOHArgs &Args) {
   EmitEOL();
 }
 
-void MCAsmStreamer::EmitDebugLabel(MCSymbol *Symbol) {
-  assert(Symbol->isUndefined() && "Cannot define a symbol twice!");
-  MCStreamer::EmitDebugLabel(Symbol);
-
-  OS << *Symbol << MAI->getDebugLabelSuffix();
-  EmitEOL();
-}
-
 void MCAsmStreamer::EmitAssemblerFlag(MCAssemblerFlag Flag) {
   switch (Flag) {
   case MCAF_SyntaxUnified:         OS << "\t.syntax unified"; break;

lib/MC/MCELFStreamer.cpp

@@ -65,10 +65,6 @@ void MCELFStreamer::EmitLabel(MCSymbol *Symbol) {
     MCELF::SetType(SD, ELF::STT_TLS);
 }
 
-void MCELFStreamer::EmitDebugLabel(MCSymbol *Symbol) {
-  EmitLabel(Symbol);
-}
-
 void MCELFStreamer::EmitAssemblerFlag(MCAssemblerFlag Flag) {
   // Let the target do whatever target specific stuff it needs to do.
   getAssembler().getBackend().handleAssemblerFlag(Flag);

lib/MC/MCMachOStreamer.cpp

@@ -60,7 +60,6 @@ public:
 
   void ChangeSection(const MCSection *Sect, const MCExpr *Subsect) override;
   void EmitLabel(MCSymbol *Symbol) override;
-  void EmitDebugLabel(MCSymbol *Symbol) override;
   void EmitEHSymAttributes(const MCSymbol *Symbol, MCSymbol *EHSymbol) override;
   void EmitAssemblerFlag(MCAssemblerFlag Flag) override;
   void EmitLinkerOptions(ArrayRef<std::string> Options) override;
@@ -162,9 +161,6 @@ void MCMachOStreamer::EmitLabel(MCSymbol *Symbol) {
   SD.setFlags(SD.getFlags() & ~SF_ReferenceTypeMask);
 }
 
-void MCMachOStreamer::EmitDebugLabel(MCSymbol *Symbol) {
-  EmitLabel(Symbol);
-}
 void MCMachOStreamer::EmitDataRegion(DataRegionData::KindTy Kind) {
   if (!getAssembler().getBackend().hasDataInCodeSupport())
     return;

lib/MC/MCNullStreamer.cpp

@@ -33,9 +33,6 @@ namespace {
       assert(getCurrentSection().first &&"Cannot emit before setting section!");
       AssignSection(Symbol, getCurrentSection().first);
     }
-    void EmitDebugLabel(MCSymbol *Symbol) override {
-      EmitLabel(Symbol);
-    }
     void EmitAssemblerFlag(MCAssemblerFlag Flag) override {}
     void EmitThumbFunc(MCSymbol *Func) override {}
 

lib/MC/MCObjectStreamer.cpp

@@ -158,10 +158,6 @@ void MCObjectStreamer::EmitLabel(MCSymbol *Symbol) {
   SD.setOffset(F->getContents().size());
 }
 
-void MCObjectStreamer::EmitDebugLabel(MCSymbol *Symbol) {
-  EmitLabel(Symbol);
-}
-
 void MCObjectStreamer::EmitULEB128Value(const MCExpr *Value) {
   int64_t IntValue;
   if (Value->EvaluateAsAbsolute(IntValue, getAssembler())) {

lib/MC/MCStreamer.cpp

@@ -239,12 +239,6 @@ void MCStreamer::EmitLabel(MCSymbol *Symbol) {
     TS->emitLabel(Symbol);
 }
 
-void MCStreamer::EmitDebugLabel(MCSymbol *Symbol) {
-  assert(!Symbol->isVariable() && "Cannot emit a variable symbol!");
-  assert(getCurrentSection().first && "Cannot emit before setting section!");
-  AssignSection(Symbol, getCurrentSection().first);
-}
-
 void MCStreamer::EmitCompactUnwindEncoding(uint32_t CompactUnwindEncoding) {
   EnsureValidFrame();
   MCDwarfFrameInfo *CurFrame = getCurrentFrameInfo();

lib/MC/WinCOFFStreamer.cpp

@@ -82,10 +82,6 @@ void MCWinCOFFStreamer::EmitLabel(MCSymbol *Symbol) {
   MCObjectStreamer::EmitLabel(Symbol);
 }
 
-void MCWinCOFFStreamer::EmitDebugLabel(MCSymbol *Symbol) {
-  EmitLabel(Symbol);
-}
-
 void MCWinCOFFStreamer::EmitAssemblerFlag(MCAssemblerFlag Flag) {
   llvm_unreachable("not implemented");
 }

lib/Target/Mips/MCTargetDesc/MipsMCAsmInfo.cpp

@@ -38,7 +38,7 @@ MipsMCAsmInfo::MipsMCAsmInfo(StringRef TT) {
   ZeroDirective               = "\t.space\t";
   GPRel32Directive            = "\t.gpword\t";
   GPRel64Directive            = "\t.gpdword\t";
-  DebugLabelSuffix            = "=.";
+  UseAssignmentForEHBegin = true;
   SupportsDebugInformation = true;
   ExceptionsType = ExceptionHandling::DwarfCFI;
   HasLEB128 = true;

test/CodeGen/Mips/mips16ex.ll

@@ -1,6 +1,8 @@
 ; RUN: llc  -march=mipsel -mcpu=mips16 -relocation-model=pic -O3 < %s | FileCheck %s -check-prefix=16
 
-;16: $eh_func_begin0=.
+;16: .cfi_personality
+;16-NEXT: [[TMP:.*]]:
+;16-NEXT: $eh_func_begin0 = ([[TMP]])
 @.str = private unnamed_addr constant [7 x i8] c"hello\0A\00", align 1
 @_ZTIi = external constant i8*
 @.str1 = private unnamed_addr constant [15 x i8] c"exception %i \0A\00", align 1