[asan] Add a flag to control asm instrumentation.

With this change, asm instrumentation is disabled by default.

llvm-svn: 208167

1 files changed, 8 insertions, 1 deletions

diff --git a/llvm/lib/Target/X86/AsmParser/X86AsmInstrumentation.cpp b/llvm/lib/Target/X86/AsmParser/X86AsmInstrumentation.cpp
index c8b541f3af6..95e4ccccb9d 100644
--- a/llvm/lib/Target/X86/AsmParser/X86AsmInstrumentation.cpp
+++ b/llvm/lib/Target/X86/AsmParser/X86AsmInstrumentation.cpp
@@ -21,10 +21,16 @@
 #include "llvm/MC/MCStreamer.h"
 #include "llvm/MC/MCSubtargetInfo.h"
 #include "llvm/MC/MCTargetOptions.h"
+#include "llvm/Support/CommandLine.h"
 
 namespace llvm {
 namespace {
 
+static cl::opt<bool> ClAsanInstrumentAssembly(
+    "asan-instrument-assembly",
+    cl::desc("instrument assembly with AddressSanitizer checks"), cl::Hidden,
+    cl::init(false));
+
 bool IsStackReg(unsigned Reg) {
   return Reg == X86::RSP || Reg == X86::ESP || Reg == X86::SP;
 }
@@ -212,7 +218,8 @@ CreateX86AsmInstrumentation(const MCTargetOptions &MCOptions,
                             const MCContext &Ctx, const MCSubtargetInfo &STI) {
   Triple T(STI.getTargetTriple());
   const bool hasCompilerRTSupport = T.isOSLinux();
-  if (hasCompilerRTSupport && MCOptions.SanitizeAddress) {
+  if (ClAsanInstrumentAssembly && hasCompilerRTSupport &&
+      MCOptions.SanitizeAddress) {
     if ((STI.getFeatureBits() & X86::Mode32Bit) != 0)
       return new X86AddressSanitizer32(STI);
     if ((STI.getFeatureBits() & X86::Mode64Bit) != 0)