[WebAssembly] Implement Address Sanitizer for Emscripten

Summary:
This diff enables address sanitizer on Emscripten.

On Emscripten, real memory starts at the value passed to --global-base.

All memory before this is used as shadow memory, and thus the shadow mapping
function is simply dividing by 8.

Reviewers: tlively, aheejin, sbc100

Reviewed By: sbc100

Subscribers: dschuff, sbc100, jgravelle-google, hiraditya, sunfish, cfe-commits, llvm-commits

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D63742

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@364468 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/Instrumentation/AddressSanitizer.cpp b/lib/Transforms/Instrumentation/AddressSanitizer.cpp
index 3190060..6821e21 100644 (file)
--- a/lib/Transforms/Instrumentation/AddressSanitizer.cpp
+++ b/lib/Transforms/Instrumentation/AddressSanitizer.cpp
@@ -109,6 +109,7 @@ static const uint64_t kNetBSD_ShadowOffset64 = 1ULL << 46;
 static const uint64_t kNetBSDKasan_ShadowOffset64 = 0xdfff900000000000;
 static const uint64_t kPS4CPU_ShadowOffset64 = 1ULL << 40;
 static const uint64_t kWindowsShadowOffset32 = 3ULL << 28;
+static const uint64_t kEmscriptenShadowOffset = 0;
 
 static const uint64_t kMyriadShadowScale = 5;
 static const uint64_t kMyriadMemoryOffset32 = 0x80000000ULL;
@@ -433,6 +434,7 @@ static ShadowMapping getShadowMapping(Triple &TargetTriple, int LongSize,
   bool IsWindows = TargetTriple.isOSWindows();
   bool IsFuchsia = TargetTriple.isOSFuchsia();
   bool IsMyriad = TargetTriple.getVendor() == llvm::Triple::Myriad;
+  bool IsEmscripten = TargetTriple.isOSEmscripten();
 
   ShadowMapping Mapping;
 
@@ -454,6 +456,8 @@ static ShadowMapping getShadowMapping(Triple &TargetTriple, int LongSize,
       Mapping.Offset = kDynamicShadowSentinel;
     else if (IsWindows)
       Mapping.Offset = kWindowsShadowOffset32;
+    else if (IsEmscripten)
+      Mapping.Offset = kEmscriptenShadowOffset;
     else if (IsMyriad) {
       uint64_t ShadowOffset = (kMyriadMemoryOffset32 + kMyriadMemorySize32 -
                                (kMyriadMemorySize32 >> Mapping.Scale));