This patch adds a flag in MCAsmInfo that indicates whether dwarf register

numbers should be printed instead of symbolic register names in
MCAsmStreamer::EmitRegisterName. This is necessary because some versions of
GNU assembler won't accept code in which symbolic register names are used in
cfi directives. There is no change in behavior unless the flag is explicitly
set to true by a backend.

llvm-svn: 134635

llvm/include/llvm/MC/MCAsmInfo.h

@@ -284,6 +284,10 @@ namespace llvm {
     // use EmitLabelOffsetDifference.
     bool DwarfUsesLabelOffsetForRanges;
 
+    /// DwarfRegNumForCFI - True if dwarf register numbers are printed
+    /// instead of symbolic register names in .cfi_* directives.
+    bool DwarfRegNumForCFI;  // Defaults to false;
+
     //===--- CBE Asm Translation Table -----------------------------------===//
 
     const char *const *AsmTransCBE;          // Defaults to empty
@@ -475,6 +479,9 @@ namespace llvm {
     bool doesDwarfUsesLabelOffsetForRanges() const {
       return DwarfUsesLabelOffsetForRanges;
     }
+    bool useDwarfRegNumForCFI() const {
+      return DwarfRegNumForCFI;
+    }
     const char *const *getAsmCBE() const {
       return AsmTransCBE;
     }

llvm/lib/MC/MCAsmInfo.cpp

@@ -78,6 +78,7 @@ MCAsmInfo::MCAsmInfo() {
   DwarfRequiresRelocationForSectionOffset = true;
   DwarfSectionOffsetDirective = 0;
   DwarfUsesLabelOffsetForRanges = true;
+  DwarfRegNumForCFI = false;
   HasMicrosoftFastStdCallMangling = false;
 
   AsmTransCBE = 0;

llvm/lib/MC/MCAsmStreamer.cpp

@@ -825,7 +825,7 @@ void MCAsmStreamer::EmitCFIEndProc() {
 }
 
 void MCAsmStreamer::EmitRegisterName(int64_t Register) {
-  if (InstPrinter) {
+  if (InstPrinter && !MAI.useDwarfRegNumForCFI()) {
     const TargetAsmInfo &asmInfo = getContext().getTargetAsmInfo();
     unsigned LLVMRegister = asmInfo.getLLVMRegNum(Register, true);
     InstPrinter->printRegName(OS, LLVMRegister);