Allow target to specify prefix for labels

Use the MCAsmInfo instead of the DataLayout, and allow
specifying a custom prefix for labels specifically. HSAIL
requires that labels begin with @, but global symbols with &.

llvm-svn: 223323

Author: arsenm

llvm/include/llvm/MC/MCAsmInfo.h

@@ -123,6 +123,10 @@ class MCAsmInfo {
   /// file.  Defaults to "L"
   const char *PrivateGlobalPrefix;
 
+  /// This prefix is used for labels for basic blocks. Defaults to the same as
+  /// PrivateGlobalPrefix.
+  const char *PrivateLabelPrefix;
+
   /// This prefix is used for symbols that should be passed through the
   /// assembler but be removed by the linker.  This is 'l' on Darwin, currently
   /// used for some ObjC metadata.  The default of "" meast that for this system
@@ -418,6 +422,7 @@ class MCAsmInfo {
 
   bool useAssignmentForEHBegin() const { return UseAssignmentForEHBegin; }
   const char *getPrivateGlobalPrefix() const { return PrivateGlobalPrefix; }
+  const char *getPrivateLabelPrefix() const { return PrivateLabelPrefix; }
   bool hasLinkerPrivateGlobalPrefix() const {
     return LinkerPrivateGlobalPrefix[0] != '\0';
   }

llvm/lib/CodeGen/MachineBasicBlock.cpp

@@ -54,9 +54,7 @@ MCSymbol *MachineBasicBlock::getSymbol() const {
   if (!CachedMCSymbol) {
     const MachineFunction *MF = getParent();
     MCContext &Ctx = MF->getContext();
-    const TargetMachine &TM = MF->getTarget();
-    const char *Prefix =
-        TM.getSubtargetImpl()->getDataLayout()->getPrivateGlobalPrefix();
+    const char *Prefix = Ctx.getAsmInfo()->getPrivateLabelPrefix();
     CachedMCSymbol = Ctx.GetOrCreateSymbol(Twine(Prefix) + "BB" +
                                            Twine(MF->getFunctionNumber()) +
                                            "_" + Twine(getNumber()));

llvm/lib/MC/MCAsmInfo.cpp

@@ -40,6 +40,7 @@ MCAsmInfo::MCAsmInfo() {
   LabelSuffix = ":";
   UseAssignmentForEHBegin = false;
   PrivateGlobalPrefix = "L";
+  PrivateLabelPrefix = PrivateGlobalPrefix;
   LinkerPrivateGlobalPrefix = "";
   InlineAsmStart = "APP";
   InlineAsmEnd = "NO_APP";

llvm/lib/MC/MCAsmInfoELF.cpp

@@ -30,4 +30,5 @@ MCAsmInfoELF::MCAsmInfoELF() {
   HasIdentDirective = true;
   WeakRefDirective = "\t.weak\t";
   PrivateGlobalPrefix = ".L";
+  PrivateLabelPrefix = ".L";
 }

llvm/lib/MC/MCParser/AsmParser.cpp

@@ -4662,7 +4662,7 @@ bool AsmParser::parseMSInlineAsm(
       OS << "$$";
       break;
     case AOK_Label:
-      OS << Ctx.getAsmInfo()->getPrivateGlobalPrefix() << AR.Label;
+      OS << Ctx.getAsmInfo()->getPrivateLabelPrefix() << AR.Label;
       break;
     case AOK_Input:
       OS << '$' << InputIdx++;

llvm/lib/Target/AArch64/MCTargetDesc/AArch64MCAsmInfo.cpp

@@ -37,6 +37,7 @@ AArch64MCAsmInfoDarwin::AArch64MCAsmInfoDarwin() {
   AssemblerDialect = AsmWriterVariant == Default ? 1 : AsmWriterVariant;
 
   PrivateGlobalPrefix = "L";
+  PrivateLabelPrefix = "L";
   SeparatorString = "%%";
   CommentString = ";";
   PointerSize = CalleeSaveStackSlotSize = 8;
@@ -79,6 +80,7 @@ AArch64MCAsmInfoELF::AArch64MCAsmInfoELF(StringRef TT) {
 
   CommentString = "//";
   PrivateGlobalPrefix = ".L";
+  PrivateLabelPrefix = ".L";
   Code32Directive = ".code\t32";
 
   Data16bitsDirective = "\t.hword\t";

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

@@ -89,6 +89,7 @@ ARMCOFFMCAsmInfoMicrosoft::ARMCOFFMCAsmInfoMicrosoft() {
   AlignmentIsInBytes = false;
 
   PrivateGlobalPrefix = "$M";
+  PrivateLabelPrefix = "$M";
 }
 
 void ARMCOFFMCAsmInfoGNU::anchor() { }
@@ -101,6 +102,7 @@ ARMCOFFMCAsmInfoGNU::ARMCOFFMCAsmInfoGNU() {
   Code16Directive = ".code\t16";
   Code32Directive = ".code\t32";
   PrivateGlobalPrefix = ".L";
+  PrivateLabelPrefix = ".L";
 
   SupportsDebugInformation = true;
   ExceptionsType = ExceptionHandling::None;

llvm/lib/Target/Mips/MCTargetDesc/MipsMCAsmInfo.cpp

@@ -34,6 +34,7 @@ MipsMCAsmInfo::MipsMCAsmInfo(StringRef TT) {
   Data32bitsDirective         = "\t.4byte\t";
   Data64bitsDirective         = "\t.8byte\t";
   PrivateGlobalPrefix         = "$";
+  PrivateLabelPrefix          = "$";
   CommentString               = "#";
   ZeroDirective               = "\t.space\t";
   GPRel32Directive            = "\t.gpword\t";

llvm/lib/Target/R600/MCTargetDesc/AMDGPUMCAsmInfo.cpp

@@ -17,6 +17,8 @@ AMDGPUMCAsmInfo::AMDGPUMCAsmInfo(StringRef &TT) : MCAsmInfoELF() {
   MaxInstLength = 16;
   SeparatorString = "\n";
   CommentString = ";";
+  PrivateGlobalPrefix = "";
+  PrivateLabelPrefix = "";
   InlineAsmStart = ";#ASMSTART";
   InlineAsmEnd = ";#ASMEND";
 

llvm/lib/Target/X86/MCTargetDesc/X86MCAsmInfo.cpp

@@ -134,6 +134,7 @@ void X86MCAsmInfoMicrosoft::anchor() { }
 X86MCAsmInfoMicrosoft::X86MCAsmInfoMicrosoft(const Triple &Triple) {
   if (Triple.getArch() == Triple::x86_64) {
     PrivateGlobalPrefix = ".L";
+    PrivateLabelPrefix = ".L";
     PointerSize = 8;
     WinEHEncodingType = WinEH::EncodingType::Itanium;
     ExceptionsType = ExceptionHandling::ItaniumWinEH;
@@ -154,6 +155,7 @@ X86MCAsmInfoGNUCOFF::X86MCAsmInfoGNUCOFF(const Triple &Triple) {
   assert(Triple.isOSWindows() && "Windows is the only supported COFF target");
   if (Triple.getArch() == Triple::x86_64) {
     PrivateGlobalPrefix = ".L";
+    PrivateLabelPrefix = ".L";
     PointerSize = 8;
     WinEHEncodingType = WinEH::EncodingType::Itanium;
     ExceptionsType = ExceptionHandling::ItaniumWinEH;