Add 'lock' prefix output support in assembly printer

- Instead of embedding 'lock' into each mnemonic of atomic
  instructions except 'xchg', we teach X86 assembly printer to output 'lock'
  prefix similar to or consistent with code emitter.

llvm-svn: 164659

2 files changed, 14 insertions, 0 deletions

diff --git a/llvm/lib/Target/X86/InstPrinter/X86ATTInstPrinter.cpp b/llvm/lib/Target/X86/InstPrinter/X86ATTInstPrinter.cpp
index 46e72f9f602..b123afa0015 100644
--- a/llvm/lib/Target/X86/InstPrinter/X86ATTInstPrinter.cpp
+++ b/llvm/lib/Target/X86/InstPrinter/X86ATTInstPrinter.cpp
@@ -15,6 +15,7 @@
 #define DEBUG_TYPE "asm-printer"
 #include "X86ATTInstPrinter.h"
 #include "X86InstComments.h"
+#include "MCTargetDesc/X86BaseInfo.h"
 #include "MCTargetDesc/X86MCTargetDesc.h"
 #include "llvm/MC/MCInst.h"
 #include "llvm/MC/MCAsmInfo.h"
@@ -38,6 +39,12 @@ void X86ATTInstPrinter::printRegName(raw_ostream &OS,
 
 void X86ATTInstPrinter::printInst(const MCInst *MI, raw_ostream &OS,
                                   StringRef Annot) {
+  const MCInstrDesc &Desc = MII.get(MI->getOpcode());
+  uint64_t TSFlags = Desc.TSFlags;
+
+  if (TSFlags & X86II::LOCK)
+    OS << "\tlock\n";
+
   // Try to print any aliases first.
   if (!printAliasInstr(MI, OS))
     printInstruction(MI, OS);
diff --git a/llvm/lib/Target/X86/InstPrinter/X86IntelInstPrinter.cpp b/llvm/lib/Target/X86/InstPrinter/X86IntelInstPrinter.cpp
index ad14e34707b..f9bb3be9d73 100644
--- a/llvm/lib/Target/X86/InstPrinter/X86IntelInstPrinter.cpp
+++ b/llvm/lib/Target/X86/InstPrinter/X86IntelInstPrinter.cpp
@@ -15,6 +15,7 @@
 #define DEBUG_TYPE "asm-printer"
 #include "X86IntelInstPrinter.h"
 #include "X86InstComments.h"
+#include "MCTargetDesc/X86BaseInfo.h"
 #include "MCTargetDesc/X86MCTargetDesc.h"
 #include "llvm/MC/MCInst.h"
 #include "llvm/MC/MCExpr.h"
@@ -32,6 +33,12 @@ void X86IntelInstPrinter::printRegName(raw_ostream &OS, unsigned RegNo) const {
 
 void X86IntelInstPrinter::printInst(const MCInst *MI, raw_ostream &OS,
                                     StringRef Annot) {
+  const MCInstrDesc &Desc = MII.get(MI->getOpcode());
+  uint64_t TSFlags = Desc.TSFlags;
+
+  if (TSFlags & X86II::LOCK)
+    OS << "\tlock\n";
+
   printInstruction(MI, OS);
 
   // Next always print the annotation.