[llvm] r174964 - [ASan] Do not use kDefaultShort64bitShadowOffset on Mac, where the binaries may get mapped at 0x100000000+ and thus may interleave with the shadow.

[Bill Wendling]

On Feb 12, 2013, at 4:41 AM, Alexander Potapenko <glider at google.com> wrote:

> Author: glider
> Date: Tue Feb 12 06:41:12 2013
> New Revision: 174964
> 
> URL: http://llvm.org/viewvc/llvm-project?rev=174964&view=rev
> Log:
> [ASan] Do not use kDefaultShort64bitShadowOffset on Mac, where the binaries may get mapped at 0x100000000+ and thus may interleave with the shadow.
> 
> Modified:
>    llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp
> 
> Modified: llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp?rev=174964&r1=174963&r2=174964&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp (original)
> +++ llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp Tue Feb 12 06:41:12 2013
> @@ -202,6 +202,7 @@ static ShadowMapping getShadowMapping(co
>                                       bool ZeroBaseShadow) {
>   llvm::Triple TargetTriple(M.getTargetTriple());
>   bool IsAndroid = TargetTriple.getEnvironment() == llvm::Triple::Android;
> +  bool IsMacOSX = TargetTriple.getOS() == llvm::Triple::MacOSX;
>   bool IsPPC64 = TargetTriple.getArch() == llvm::Triple::ppc64;
>   bool IsX86_64 = TargetTriple.getArch() == llvm::Triple::x86_64;
> 
> @@ -215,7 +216,7 @@ static ShadowMapping getShadowMapping(co
>   Mapping.Offset = (IsAndroid || ZeroBaseShadow) ? 0 :
>       (LongSize == 32 ? kDefaultShadowOffset32 :
>        IsPPC64 ? kPPC64_ShadowOffset64 : kDefaultShadowOffset64);
> -  if (!ZeroBaseShadow && ClShort64BitOffset && IsX86_64) {
> +  if (!ZeroBaseShadow && ClShort64BitOffset && IsX86_64 && !IsMacOSX) {
>     assert(LongSize == 64);
>     Mapping.Offset = kDefaultShort64bitShadowOffset;
>   } if (!ZeroBaseShadow && ClMappingOffsetLog >= 0) {
> 
This 'if' here is on the same line as the previous '}'. Is that intended? or is there a missing 'else' here?

-bw