quantum created this revision.
quantum added reviewers: tlively, aheejin.
Herald added subscribers: llvm-commits, cfe-commits, sunfish, hiraditya,
jgravelle-google, sbc100, dschuff.
Herald added projects: clang, LLVM.
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.
A symbol __global_base is added so that code may know where the shadow
memory ends and real memory begins.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D63742
Files:
clang/lib/Driver/ToolChains/WebAssembly.cpp
clang/test/Driver/wasm-toolchain.c
lld/test/wasm/global-base.ll
lld/wasm/Driver.cpp
lld/wasm/Symbols.cpp
lld/wasm/Symbols.h
lld/wasm/Writer.cpp
llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
Index: llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
===================================================================
--- llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
+++ llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
@@ -112,6 +112,7 @@
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;
@@ -437,6 +438,7 @@
bool IsWindows = TargetTriple.isOSWindows();
bool IsFuchsia = TargetTriple.isOSFuchsia();
bool IsMyriad = TargetTriple.getVendor() == llvm::Triple::Myriad;
+ bool IsEmscripten = TargetTriple.isOSEmscripten();
ShadowMapping Mapping;
@@ -459,6 +461,8 @@
Mapping.Offset = IsX86 ? kIOSSimShadowOffset32 : kIOSShadowOffset32;
else if (IsWindows)
Mapping.Offset = kWindowsShadowOffset32;
+ else if (IsEmscripten)
+ Mapping.Offset = kEmscriptenShadowOffset;
else if (IsMyriad) {
uint64_t ShadowOffset = (kMyriadMemoryOffset32 + kMyriadMemorySize32 -
(kMyriadMemorySize32 >> Mapping.Scale));
Index: lld/wasm/Writer.cpp
===================================================================
--- lld/wasm/Writer.cpp
+++ lld/wasm/Writer.cpp
@@ -224,6 +224,9 @@
log("mem: global base = " + Twine(Config->GlobalBase));
}
+ if (WasmSym::GlobalBase)
+ WasmSym::GlobalBase->setVirtualAddress(Config->GlobalBase);
+
uint32_t DataStart = MemoryPtr;
// Arbitrarily set __dso_handle handle to point to the start of the data
Index: lld/wasm/Symbols.h
===================================================================
--- lld/wasm/Symbols.h
+++ lld/wasm/Symbols.h
@@ -415,6 +415,10 @@
// linker-generated symbols
struct WasmSym {
+ // __global_base
+ // Symbol marking the start of the global section.
+ static DefinedData *GlobalBase;
+
// __stack_pointer
// Global that holds the address of the top of the explicit value stack in
// linear memory.
Index: lld/wasm/Symbols.cpp
===================================================================
--- lld/wasm/Symbols.cpp
+++ lld/wasm/Symbols.cpp
@@ -28,6 +28,7 @@
DefinedFunction *WasmSym::ApplyRelocs;
DefinedData *WasmSym::DsoHandle;
DefinedData *WasmSym::DataEnd;
+DefinedData *WasmSym::GlobalBase;
DefinedData *WasmSym::HeapBase;
GlobalSymbol *WasmSym::StackPointer;
UndefinedGlobal *WasmSym::TableBase;
Index: lld/wasm/Driver.cpp
===================================================================
--- lld/wasm/Driver.cpp
+++ lld/wasm/Driver.cpp
@@ -482,6 +482,7 @@
WasmSym::StackPointer = Symtab->addSyntheticGlobal(
"__stack_pointer", WASM_SYMBOL_VISIBILITY_HIDDEN, StackPointer);
WasmSym::DataEnd = Symtab->addOptionalDataSymbol("__data_end");
+ WasmSym::GlobalBase = Symtab->addOptionalDataSymbol("__global_base");
WasmSym::HeapBase = Symtab->addOptionalDataSymbol("__heap_base");
}
Index: lld/test/wasm/global-base.ll
===================================================================
--- /dev/null
+++ lld/test/wasm/global-base.ll
@@ -0,0 +1,73 @@
+; RUN: llc -filetype=obj %s -o %t.o
+
+target triple = "wasm32-unknown-unknown"
+
+; RUN: wasm-ld -no-gc-sections --export=__global_base --export=__data_end --allow-undefined --no-entry -o %t.wasm %t.o
+; RUN: obj2yaml %t.wasm | FileCheck %s -check-prefix=CHECK-1024
+; CHECK-1024: - Type: GLOBAL
+; CHECK-1024-NEXT: Globals:
+; CHECK-1024-NEXT: - Index: 0
+; CHECK-1024-NEXT: Type: I32
+; CHECK-1024-NEXT: Mutable: true
+; CHECK-1024-NEXT: InitExpr:
+; CHECK-1024-NEXT: Opcode: I32_CONST
+; CHECK-1024-NEXT: Value: 66560
+; CHECK-1024-NEXT: - Index: 1
+; CHECK-1024-NEXT: Type: I32
+; CHECK-1024-NEXT: Mutable: false
+; CHECK-1024-NEXT: InitExpr:
+; CHECK-1024-NEXT: Opcode: I32_CONST
+; CHECK-1024-NEXT: Value: 1024
+; CHECK-1024-NEXT: - Index: 2
+; CHECK-1024-NEXT: Type: I32
+; CHECK-1024-NEXT: Mutable: false
+; CHECK-1024-NEXT: InitExpr:
+; CHECK-1024-NEXT: Opcode: I32_CONST
+; CHECK-1024-NEXT: Value: 1024
+
+; CHECK-1024: - Type: EXPORT
+; CHECK-1024-NEXT: Exports:
+; CHECK-1024-NEXT: - Name: memory
+; CHECK-1024-NEXT: Kind: MEMORY
+; CHECK-1024-NEXT: Index: 0
+; CHECK-1024-NEXT: - Name: __data_end
+; CHECK-1024-NEXT: Kind: GLOBAL
+; CHECK-1024-NEXT: Index: 1
+; CHECK-1024-NEXT: - Name: __global_base
+; CHECK-1024-NEXT: Kind: GLOBAL
+; CHECK-1024-NEXT: Index: 2
+
+; RUN: wasm-ld -no-gc-sections --export=__global_base --export=__data_end --allow-undefined --global-base=16777216 --no-entry -o %t.wasm %t.o
+; RUN: obj2yaml %t.wasm | FileCheck %s -check-prefix=CHECK-16777216
+; CHECK-16777216: - Type: GLOBAL
+; CHECK-16777216-NEXT: Globals:
+; CHECK-16777216-NEXT: - Index: 0
+; CHECK-16777216-NEXT: Type: I32
+; CHECK-16777216-NEXT: Mutable: true
+; CHECK-16777216-NEXT: InitExpr:
+; CHECK-16777216-NEXT: Opcode: I32_CONST
+; CHECK-16777216-NEXT: Value: 16842752
+; CHECK-16777216-NEXT: - Index: 1
+; CHECK-16777216-NEXT: Type: I32
+; CHECK-16777216-NEXT: Mutable: false
+; CHECK-16777216-NEXT: InitExpr:
+; CHECK-16777216-NEXT: Opcode: I32_CONST
+; CHECK-16777216-NEXT: Value: 16777216
+; CHECK-16777216-NEXT: - Index: 2
+; CHECK-16777216-NEXT: Type: I32
+; CHECK-16777216-NEXT: Mutable: false
+; CHECK-16777216-NEXT: InitExpr:
+; CHECK-16777216-NEXT: Opcode: I32_CONST
+; CHECK-16777216-NEXT: Value: 16777216
+
+; CHECK-16777216: - Type: EXPORT
+; CHECK-16777216-NEXT: Exports:
+; CHECK-16777216-NEXT: - Name: memory
+; CHECK-16777216-NEXT: Kind: MEMORY
+; CHECK-16777216-NEXT: Index: 0
+; CHECK-16777216-NEXT: - Name: __data_end
+; CHECK-16777216-NEXT: Kind: GLOBAL
+; CHECK-16777216-NEXT: Index: 1
+; CHECK-16777216-NEXT: - Name: __global_base
+; CHECK-16777216-NEXT: Kind: GLOBAL
+; CHECK-16777216-NEXT: Index: 2
Index: clang/test/Driver/wasm-toolchain.c
===================================================================
--- clang/test/Driver/wasm-toolchain.c
+++ clang/test/Driver/wasm-toolchain.c
@@ -49,3 +49,7 @@
// '-pthread' not allowed with '-mno-atomics'
// RUN: %clang -### -no-canonical-prefixes -target wasm32-unknown-unknown --sysroot=/foo %s -pthread -mno-atomics 2>&1 | 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"
Index: clang/lib/Driver/ToolChains/WebAssembly.cpp
===================================================================
--- clang/lib/Driver/ToolChains/WebAssembly.cpp
+++ clang/lib/Driver/ToolChains/WebAssembly.cpp
@@ -211,7 +211,7 @@
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;
}
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