[WebAssembly] Implement Address Sanitizer for Emscripten

quantum5 · quantum5 · commit 9aad997a5aae · 2019-06-26T20:16:14.000Z
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 llvm-svn: 364468
diff --git a/clang/lib/Driver/ToolChains/WebAssembly.cpp b/clang/lib/Driver/ToolChains/WebAssembly.cpp
@@ -238,7 +238,7 @@ void WebAssembly::AddCXXStdlibLibArgs(const llvm::opt::ArgList &Args,
 SanitizerMask WebAssembly::getSupportedSanitizers() const {
   SanitizerMask Res = ToolChain::getSupportedSanitizers();
   if (getTriple().isOSEmscripten()) {
-    Res |= SanitizerKind::Vptr | SanitizerKind::Leak;
+    Res |= SanitizerKind::Vptr | SanitizerKind::Leak | SanitizerKind::Address;
   }
   return Res;
 }
diff --git a/clang/test/Driver/wasm-toolchain.c b/clang/test/Driver/wasm-toolchain.c
@@ -60,3 +60,7 @@
 // RUN:     --sysroot=/foo %s -pthread -mno-atomics 2>&1 \
 // RUN:   | FileCheck -check-prefix=PTHREAD_NO_ATOMICS %s
 // PTHREAD_NO_ATOMICS: invalid argument '-pthread' not allowed with '-mno-atomics'
+
+// RUN: %clang %s -### -fsanitize=address -target wasm32-unknown-emscripten 2>&1 | FileCheck -check-prefix=CHECK-ASAN-EMSCRIPTEN %s
+// CHECK-ASAN-EMSCRIPTEN: "-fsanitize=address"
+// CHECK-ASAN-EMSCRIPTEN: "-fsanitize-address-globals-dead-stripping"
diff --git a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp b/llvm/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));

Original file line number	Diff line number	Diff line change
`@@ -238,7 +238,7 @@ void WebAssembly::AddCXXStdlibLibArgs(const llvm::opt::ArgList &Args,`
`238`	`238`	`SanitizerMask WebAssembly::getSupportedSanitizers() const {`
`239`	`239`	`SanitizerMask Res = ToolChain::getSupportedSanitizers();`
`240`	`240`	`if (getTriple().isOSEmscripten()) {`
`241`		`- Res \|= SanitizerKind::Vptr \| SanitizerKind::Leak;`
	`241`	`+ Res \|= SanitizerKind::Vptr \| SanitizerKind::Leak \| SanitizerKind::Address;`
`242`	`242`	`}`
`243`	`243`	`return Res;`
`244`	`244`	`}`