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[ASan] Collect unmangled names of global variables in Clang to print them in error reports.

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Currently ASan instrumentation pass creates a string with global name
for each instrumented global (to include global names in the error report). Global
name is already mangled at this point, and we may not be able to demangle it
at runtime (e.g. there is no __cxa_demangle on Android).

Instead, create a string with fully qualified global name in Clang, and pass it
to ASan instrumentation pass in llvm.asan.globals metadata. If there is no metadata
for some global, ASan will use the original algorithm.

This fixes https://code.google.com/p/address-sanitizer/issues/detail?id=264.

llvm-svn: 212872
This commit is contained in:
Alexey Samsonov
2014-07-12 00:42:52 +00:00
parent fc31efe95a
commit 15c9669615
9 changed files with 86 additions and 47 deletions
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42
clang/lib/CodeGen/CodeGenModule.cpp
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@@ -1952,7 +1952,7 @@ void CodeGenModule::EmitGlobalVarDefinition(const VarDecl *D) {
if (NeedsGlobalCtor || NeedsGlobalDtor)
EmitCXXGlobalVarDeclInitFunc(D, GV, NeedsGlobalCtor);
reportGlobalToASan(GV, D->getLocation(), NeedsGlobalCtor);
reportGlobalToASan(GV, *D, NeedsGlobalCtor);
// Emit global variable debug information.
if (CGDebugInfo *DI = getModuleDebugInfo())
@@ -1961,24 +1961,25 @@ void CodeGenModule::EmitGlobalVarDefinition(const VarDecl *D) {
}
void CodeGenModule::reportGlobalToASan(llvm::GlobalVariable *GV,
SourceLocation Loc, bool IsDynInit) {
SourceLocation Loc, StringRef Name,
bool IsDynInit) {
if (!LangOpts.Sanitize.Address)
return;
IsDynInit &= !SanitizerBL.isIn(*GV, "init");
bool IsBlacklisted = SanitizerBL.isIn(*GV);
llvm::LLVMContext &LLVMCtx = TheModule.getContext();
llvm::GlobalVariable *LocDescr = nullptr;
llvm::GlobalVariable *GlobalName = nullptr;
if (!IsBlacklisted) {
// Don't generate source location if a global is blacklisted - it won't
// be instrumented anyway.
// Don't generate source location and global name if it is blacklisted -
// it won't be instrumented anyway.
PresumedLoc PLoc = Context.getSourceManager().getPresumedLoc(Loc);
if (PLoc.isValid()) {
llvm::Constant *LocData[] = {
GetAddrOfConstantCString(PLoc.getFilename()),
llvm::ConstantInt::get(llvm::Type::getInt32Ty(LLVMCtx), PLoc.getLine()),
llvm::ConstantInt::get(llvm::Type::getInt32Ty(LLVMCtx),
llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext),
PLoc.getLine()),
llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext),
PLoc.getColumn()),
};
auto LocStruct = llvm::ConstantStruct::getAnon(LocData);
@@ -1990,14 +1991,17 @@ void CodeGenModule::reportGlobalToASan(llvm::GlobalVariable *GV,
// the optimizer before the ASan instrumentation pass.
addCompilerUsedGlobal(LocDescr);
}
if (!Name.empty()) {
GlobalName = GetAddrOfConstantCString(Name);
// GlobalName shouldn't be removed by the optimizer.
addCompilerUsedGlobal(GlobalName);
}
}
llvm::Value *GlobalMetadata[] = {
GV,
LocDescr,
llvm::ConstantInt::get(llvm::Type::getInt1Ty(LLVMCtx), IsDynInit),
llvm::ConstantInt::get(llvm::Type::getInt1Ty(LLVMCtx), IsBlacklisted)
};
GV, LocDescr, GlobalName,
llvm::ConstantInt::get(llvm::Type::getInt1Ty(VMContext), IsDynInit),
llvm::ConstantInt::get(llvm::Type::getInt1Ty(VMContext), IsBlacklisted)};
llvm::MDNode *ThisGlobal = llvm::MDNode::get(VMContext, GlobalMetadata);
llvm::NamedMDNode *AsanGlobals =
@@ -2005,6 +2009,16 @@ void CodeGenModule::reportGlobalToASan(llvm::GlobalVariable *GV,
AsanGlobals->addOperand(ThisGlobal);
}
void CodeGenModule::reportGlobalToASan(llvm::GlobalVariable *GV,
const VarDecl &D, bool IsDynInit) {
if (!LangOpts.Sanitize.Address)
return;
std::string QualName;
llvm::raw_string_ostream OS(QualName);
D.printQualifiedName(OS);
reportGlobalToASan(GV, D.getLocation(), OS.str(), IsDynInit);
}
static bool isVarDeclStrongDefinition(const VarDecl *D, bool NoCommon) {
// Don't give variables common linkage if -fno-common was specified unless it
// was overridden by a NoCommon attribute.
@@ -2810,7 +2824,7 @@ CodeGenModule::GetAddrOfConstantStringFromLiteral(const StringLiteral *S) {
if (Entry)
Entry->setValue(GV);
reportGlobalToASan(GV, S->getStrTokenLoc(0));
reportGlobalToASan(GV, S->getStrTokenLoc(0), "<string literal>");
return GV;
}