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-rw-r--r--lib/Transforms/Instrumentation/AddressSanitizer.cpp334
1 files changed, 189 insertions, 145 deletions
diff --git a/lib/Transforms/Instrumentation/AddressSanitizer.cpp b/lib/Transforms/Instrumentation/AddressSanitizer.cpp
index 9c4b417e35e1..ffd518e52968 100644
--- a/lib/Transforms/Instrumentation/AddressSanitizer.cpp
+++ b/lib/Transforms/Instrumentation/AddressSanitizer.cpp
@@ -600,6 +600,22 @@ private:
void initializeCallbacks(Module &M);
bool InstrumentGlobals(IRBuilder<> &IRB, Module &M);
+ void InstrumentGlobalsCOFF(IRBuilder<> &IRB, Module &M,
+ ArrayRef<GlobalVariable *> ExtendedGlobals,
+ ArrayRef<Constant *> MetadataInitializers);
+ void InstrumentGlobalsMachO(IRBuilder<> &IRB, Module &M,
+ ArrayRef<GlobalVariable *> ExtendedGlobals,
+ ArrayRef<Constant *> MetadataInitializers);
+ void
+ InstrumentGlobalsWithMetadataArray(IRBuilder<> &IRB, Module &M,
+ ArrayRef<GlobalVariable *> ExtendedGlobals,
+ ArrayRef<Constant *> MetadataInitializers);
+
+ GlobalVariable *CreateMetadataGlobal(Module &M, Constant *Initializer,
+ StringRef OriginalName);
+ void SetComdatForGlobalMetadata(GlobalVariable *G, GlobalVariable *Metadata);
+ IRBuilder<> CreateAsanModuleDtor(Module &M);
+
bool ShouldInstrumentGlobal(GlobalVariable *G);
bool ShouldUseMachOGlobalsSection() const;
StringRef getGlobalMetadataSection() const;
@@ -1553,17 +1569,173 @@ void AddressSanitizerModule::initializeCallbacks(Module &M) {
// Declare the functions that find globals in a shared object and then invoke
// the (un)register function on them.
- AsanRegisterImageGlobals = checkSanitizerInterfaceFunction(
- M.getOrInsertFunction(kAsanRegisterImageGlobalsName,
- IRB.getVoidTy(), IntptrTy, nullptr));
+ AsanRegisterImageGlobals =
+ checkSanitizerInterfaceFunction(M.getOrInsertFunction(
+ kAsanRegisterImageGlobalsName, IRB.getVoidTy(), IntptrTy, nullptr));
AsanRegisterImageGlobals->setLinkage(Function::ExternalLinkage);
- AsanUnregisterImageGlobals = checkSanitizerInterfaceFunction(
- M.getOrInsertFunction(kAsanUnregisterImageGlobalsName,
- IRB.getVoidTy(), IntptrTy, nullptr));
+ AsanUnregisterImageGlobals =
+ checkSanitizerInterfaceFunction(M.getOrInsertFunction(
+ kAsanUnregisterImageGlobalsName, IRB.getVoidTy(), IntptrTy, nullptr));
AsanUnregisterImageGlobals->setLinkage(Function::ExternalLinkage);
}
+// Put the metadata and the instrumented global in the same group. This ensures
+// that the metadata is discarded if the instrumented global is discarded.
+void AddressSanitizerModule::SetComdatForGlobalMetadata(
+ GlobalVariable *G, GlobalVariable *Metadata) {
+ Module &M = *G->getParent();
+ Comdat *C = G->getComdat();
+ if (!C) {
+ if (!G->hasName()) {
+ // If G is unnamed, it must be internal. Give it an artificial name
+ // so we can put it in a comdat.
+ assert(G->hasLocalLinkage());
+ G->setName(Twine(kAsanGenPrefix) + "_anon_global");
+ }
+ C = M.getOrInsertComdat(G->getName());
+ // Make this IMAGE_COMDAT_SELECT_NODUPLICATES on COFF.
+ if (TargetTriple.isOSBinFormatCOFF())
+ C->setSelectionKind(Comdat::NoDuplicates);
+ G->setComdat(C);
+ }
+
+ assert(G->hasComdat());
+ Metadata->setComdat(G->getComdat());
+}
+
+// Create a separate metadata global and put it in the appropriate ASan
+// global registration section.
+GlobalVariable *
+AddressSanitizerModule::CreateMetadataGlobal(Module &M, Constant *Initializer,
+ StringRef OriginalName) {
+ GlobalVariable *Metadata =
+ new GlobalVariable(M, Initializer->getType(), false,
+ GlobalVariable::InternalLinkage, Initializer,
+ Twine("__asan_global_") +
+ GlobalValue::getRealLinkageName(OriginalName));
+ Metadata->setSection(getGlobalMetadataSection());
+ return Metadata;
+}
+
+IRBuilder<> AddressSanitizerModule::CreateAsanModuleDtor(Module &M) {
+ Function *AsanDtorFunction =
+ Function::Create(FunctionType::get(Type::getVoidTy(*C), false),
+ GlobalValue::InternalLinkage, kAsanModuleDtorName, &M);
+ BasicBlock *AsanDtorBB = BasicBlock::Create(*C, "", AsanDtorFunction);
+ appendToGlobalDtors(M, AsanDtorFunction, kAsanCtorAndDtorPriority);
+
+ return IRBuilder<>(ReturnInst::Create(*C, AsanDtorBB));
+}
+
+void AddressSanitizerModule::InstrumentGlobalsCOFF(
+ IRBuilder<> &IRB, Module &M, ArrayRef<GlobalVariable *> ExtendedGlobals,
+ ArrayRef<Constant *> MetadataInitializers) {
+ assert(ExtendedGlobals.size() == MetadataInitializers.size());
+ auto &DL = M.getDataLayout();
+
+ for (size_t i = 0; i < ExtendedGlobals.size(); i++) {
+ Constant *Initializer = MetadataInitializers[i];
+ GlobalVariable *G = ExtendedGlobals[i];
+ GlobalVariable *Metadata =
+ CreateMetadataGlobal(M, Initializer, G->getName());
+
+ // The MSVC linker always inserts padding when linking incrementally. We
+ // cope with that by aligning each struct to its size, which must be a power
+ // of two.
+ unsigned SizeOfGlobalStruct = DL.getTypeAllocSize(Initializer->getType());
+ assert(isPowerOf2_32(SizeOfGlobalStruct) &&
+ "global metadata will not be padded appropriately");
+ Metadata->setAlignment(SizeOfGlobalStruct);
+
+ SetComdatForGlobalMetadata(G, Metadata);
+ }
+}
+
+void AddressSanitizerModule::InstrumentGlobalsMachO(
+ IRBuilder<> &IRB, Module &M, ArrayRef<GlobalVariable *> ExtendedGlobals,
+ ArrayRef<Constant *> MetadataInitializers) {
+ assert(ExtendedGlobals.size() == MetadataInitializers.size());
+
+ // On recent Mach-O platforms, use a structure which binds the liveness of
+ // the global variable to the metadata struct. Keep the list of "Liveness" GV
+ // created to be added to llvm.compiler.used
+ StructType *LivenessTy = StructType::get(IntptrTy, IntptrTy, nullptr);
+ SmallVector<GlobalValue *, 16> LivenessGlobals(ExtendedGlobals.size());
+
+ for (size_t i = 0; i < ExtendedGlobals.size(); i++) {
+ Constant *Initializer = MetadataInitializers[i];
+ GlobalVariable *G = ExtendedGlobals[i];
+ GlobalVariable *Metadata =
+ CreateMetadataGlobal(M, Initializer, G->getName());
+
+ // On recent Mach-O platforms, we emit the global metadata in a way that
+ // allows the linker to properly strip dead globals.
+ auto LivenessBinder = ConstantStruct::get(
+ LivenessTy, Initializer->getAggregateElement(0u),
+ ConstantExpr::getPointerCast(Metadata, IntptrTy), nullptr);
+ GlobalVariable *Liveness = new GlobalVariable(
+ M, LivenessTy, false, GlobalVariable::InternalLinkage, LivenessBinder,
+ Twine("__asan_binder_") + G->getName());
+ Liveness->setSection("__DATA,__asan_liveness,regular,live_support");
+ LivenessGlobals[i] = Liveness;
+ }
+
+ // Update llvm.compiler.used, adding the new liveness globals. This is
+ // needed so that during LTO these variables stay alive. The alternative
+ // would be to have the linker handling the LTO symbols, but libLTO
+ // current API does not expose access to the section for each symbol.
+ if (!LivenessGlobals.empty())
+ appendToCompilerUsed(M, LivenessGlobals);
+
+ // RegisteredFlag serves two purposes. First, we can pass it to dladdr()
+ // to look up the loaded image that contains it. Second, we can store in it
+ // whether registration has already occurred, to prevent duplicate
+ // registration.
+ //
+ // common linkage ensures that there is only one global per shared library.
+ GlobalVariable *RegisteredFlag = new GlobalVariable(
+ M, IntptrTy, false, GlobalVariable::CommonLinkage,
+ ConstantInt::get(IntptrTy, 0), kAsanGlobalsRegisteredFlagName);
+ RegisteredFlag->setVisibility(GlobalVariable::HiddenVisibility);
+
+ IRB.CreateCall(AsanRegisterImageGlobals,
+ {IRB.CreatePointerCast(RegisteredFlag, IntptrTy)});
+
+ // We also need to unregister globals at the end, e.g., when a shared library
+ // gets closed.
+ IRBuilder<> IRB_Dtor = CreateAsanModuleDtor(M);
+ IRB_Dtor.CreateCall(AsanUnregisterImageGlobals,
+ {IRB.CreatePointerCast(RegisteredFlag, IntptrTy)});
+}
+
+void AddressSanitizerModule::InstrumentGlobalsWithMetadataArray(
+ IRBuilder<> &IRB, Module &M, ArrayRef<GlobalVariable *> ExtendedGlobals,
+ ArrayRef<Constant *> MetadataInitializers) {
+ assert(ExtendedGlobals.size() == MetadataInitializers.size());
+ unsigned N = ExtendedGlobals.size();
+ assert(N > 0);
+
+ // On platforms that don't have a custom metadata section, we emit an array
+ // of global metadata structures.
+ ArrayType *ArrayOfGlobalStructTy =
+ ArrayType::get(MetadataInitializers[0]->getType(), N);
+ auto AllGlobals = new GlobalVariable(
+ M, ArrayOfGlobalStructTy, false, GlobalVariable::InternalLinkage,
+ ConstantArray::get(ArrayOfGlobalStructTy, MetadataInitializers), "");
+
+ IRB.CreateCall(AsanRegisterGlobals,
+ {IRB.CreatePointerCast(AllGlobals, IntptrTy),
+ ConstantInt::get(IntptrTy, N)});
+
+ // We also need to unregister globals at the end, e.g., when a shared library
+ // gets closed.
+ IRBuilder<> IRB_Dtor = CreateAsanModuleDtor(M);
+ IRB_Dtor.CreateCall(AsanUnregisterGlobals,
+ {IRB.CreatePointerCast(AllGlobals, IntptrTy),
+ ConstantInt::get(IntptrTy, N)});
+}
+
// This function replaces all global variables with new variables that have
// trailing redzones. It also creates a function that poisons
// redzones and inserts this function into llvm.global_ctors.
@@ -1580,9 +1752,6 @@ bool AddressSanitizerModule::InstrumentGlobals(IRBuilder<> &IRB, Module &M) {
if (n == 0) return false;
auto &DL = M.getDataLayout();
- bool UseComdatMetadata = TargetTriple.isOSBinFormatCOFF();
- bool UseMachOGlobalsSection = ShouldUseMachOGlobalsSection();
- bool UseMetadataArray = !(UseComdatMetadata || UseMachOGlobalsSection);
// A global is described by a structure
// size_t beg;
@@ -1597,19 +1766,8 @@ bool AddressSanitizerModule::InstrumentGlobals(IRBuilder<> &IRB, Module &M) {
StructType *GlobalStructTy =
StructType::get(IntptrTy, IntptrTy, IntptrTy, IntptrTy, IntptrTy,
IntptrTy, IntptrTy, IntptrTy, nullptr);
- unsigned SizeOfGlobalStruct = DL.getTypeAllocSize(GlobalStructTy);
- assert(isPowerOf2_32(SizeOfGlobalStruct) &&
- "global metadata will not be padded appropriately");
- SmallVector<Constant *, 16> Initializers(UseMetadataArray ? n : 0);
-
- // On recent Mach-O platforms, use a structure which binds the liveness of
- // the global variable to the metadata struct. Keep the list of "Liveness" GV
- // created to be added to llvm.compiler.used
- StructType *LivenessTy = nullptr;
- if (UseMachOGlobalsSection)
- LivenessTy = StructType::get(IntptrTy, IntptrTy, nullptr);
- SmallVector<GlobalValue *, 16> LivenessGlobals(
- UseMachOGlobalsSection ? n : 0);
+ SmallVector<GlobalVariable *, 16> NewGlobals(n);
+ SmallVector<Constant *, 16> Initializers(n);
bool HasDynamicallyInitializedGlobals = false;
@@ -1681,25 +1839,7 @@ bool AddressSanitizerModule::InstrumentGlobals(IRBuilder<> &IRB, Module &M) {
ConstantExpr::getGetElementPtr(NewTy, NewGlobal, Indices2, true));
NewGlobal->takeName(G);
G->eraseFromParent();
- G = NewGlobal;
-
- if (UseComdatMetadata) {
- // Get or create a COMDAT for G so that we can use it with our metadata.
- Comdat *C = G->getComdat();
- if (!C) {
- if (!G->hasName()) {
- // If G is unnamed, it must be internal. Give it an artificial name
- // so we can put it in a comdat.
- assert(G->hasLocalLinkage());
- G->setName(Twine(kAsanGenPrefix) + "_anon_global");
- }
- C = M.getOrInsertComdat(G->getName());
- // Make this IMAGE_COMDAT_SELECT_NODUPLICATES on COFF.
- if (TargetTriple.isOSBinFormatCOFF())
- C->setSelectionKind(Comdat::NoDuplicates);
- G->setComdat(C);
- }
- }
+ NewGlobals[i] = NewGlobal;
Constant *SourceLoc;
if (!MD.SourceLoc.empty()) {
@@ -1750,117 +1890,21 @@ bool AddressSanitizerModule::InstrumentGlobals(IRBuilder<> &IRB, Module &M) {
DEBUG(dbgs() << "NEW GLOBAL: " << *NewGlobal << "\n");
- // If we aren't using separate metadata globals, add it to the initializer
- // list and continue.
- if (UseMetadataArray) {
- Initializers[i] = Initializer;
- continue;
- }
-
- // Create a separate metadata global and put it in the appropriate ASan
- // global registration section.
- GlobalVariable *Metadata = new GlobalVariable(
- M, GlobalStructTy, false, GlobalVariable::InternalLinkage,
- Initializer, Twine("__asan_global_") +
- GlobalValue::getRealLinkageName(G->getName()));
- Metadata->setSection(getGlobalMetadataSection());
-
- // We don't want any padding, but we also need a reasonable alignment.
- // The MSVC linker always inserts padding when linking incrementally. We
- // cope with that by aligning each struct to its size, which must be a power
- // of two.
- Metadata->setAlignment(SizeOfGlobalStruct);
-
- // On platforms that support comdats, put the metadata and the
- // instrumented global in the same group. This ensures that the metadata
- // is discarded if the instrumented global is discarded.
- if (UseComdatMetadata) {
- assert(G->hasComdat());
- Metadata->setComdat(G->getComdat());
- continue;
- }
- assert(UseMachOGlobalsSection);
+ Initializers[i] = Initializer;
+ }
- // On recent Mach-O platforms, we emit the global metadata in a way that
- // allows the linker to properly strip dead globals.
- auto LivenessBinder = ConstantStruct::get(
- LivenessTy, Initializer->getAggregateElement(0u),
- ConstantExpr::getPointerCast(Metadata, IntptrTy), nullptr);
- GlobalVariable *Liveness = new GlobalVariable(
- M, LivenessTy, false, GlobalVariable::InternalLinkage, LivenessBinder,
- Twine("__asan_binder_") + G->getName());
- Liveness->setSection("__DATA,__asan_liveness,regular,live_support");
- LivenessGlobals[i] = Liveness;
+ if (TargetTriple.isOSBinFormatCOFF()) {
+ InstrumentGlobalsCOFF(IRB, M, NewGlobals, Initializers);
+ } else if (ShouldUseMachOGlobalsSection()) {
+ InstrumentGlobalsMachO(IRB, M, NewGlobals, Initializers);
+ } else {
+ InstrumentGlobalsWithMetadataArray(IRB, M, NewGlobals, Initializers);
}
// Create calls for poisoning before initializers run and unpoisoning after.
if (HasDynamicallyInitializedGlobals)
createInitializerPoisonCalls(M, ModuleName);
- // Platforms with a dedicated metadata section don't need to emit any more
- // code.
- if (UseComdatMetadata)
- return true;
-
- GlobalVariable *AllGlobals = nullptr;
- GlobalVariable *RegisteredFlag = nullptr;
-
- if (UseMachOGlobalsSection) {
- // RegisteredFlag serves two purposes. First, we can pass it to dladdr()
- // to look up the loaded image that contains it. Second, we can store in it
- // whether registration has already occurred, to prevent duplicate
- // registration.
- //
- // common linkage ensures that there is only one global per shared library.
- RegisteredFlag = new GlobalVariable(
- M, IntptrTy, false, GlobalVariable::CommonLinkage,
- ConstantInt::get(IntptrTy, 0), kAsanGlobalsRegisteredFlagName);
- RegisteredFlag->setVisibility(GlobalVariable::HiddenVisibility);
-
- // Update llvm.compiler.used, adding the new liveness globals. This is
- // needed so that during LTO these variables stay alive. The alternative
- // would be to have the linker handling the LTO symbols, but libLTO
- // current API does not expose access to the section for each symbol.
- if (!LivenessGlobals.empty())
- appendToCompilerUsed(M, LivenessGlobals);
- } else if (UseMetadataArray) {
- // On platforms that don't have a custom metadata section, we emit an array
- // of global metadata structures.
- ArrayType *ArrayOfGlobalStructTy = ArrayType::get(GlobalStructTy, n);
- AllGlobals = new GlobalVariable(
- M, ArrayOfGlobalStructTy, false, GlobalVariable::InternalLinkage,
- ConstantArray::get(ArrayOfGlobalStructTy, Initializers), "");
- }
-
- // Create a call to register the globals with the runtime.
- if (UseMachOGlobalsSection) {
- IRB.CreateCall(AsanRegisterImageGlobals,
- {IRB.CreatePointerCast(RegisteredFlag, IntptrTy)});
- } else {
- IRB.CreateCall(AsanRegisterGlobals,
- {IRB.CreatePointerCast(AllGlobals, IntptrTy),
- ConstantInt::get(IntptrTy, n)});
- }
-
- // We also need to unregister globals at the end, e.g., when a shared library
- // gets closed.
- Function *AsanDtorFunction =
- Function::Create(FunctionType::get(Type::getVoidTy(*C), false),
- GlobalValue::InternalLinkage, kAsanModuleDtorName, &M);
- BasicBlock *AsanDtorBB = BasicBlock::Create(*C, "", AsanDtorFunction);
- IRBuilder<> IRB_Dtor(ReturnInst::Create(*C, AsanDtorBB));
-
- if (UseMachOGlobalsSection) {
- IRB_Dtor.CreateCall(AsanUnregisterImageGlobals,
- {IRB.CreatePointerCast(RegisteredFlag, IntptrTy)});
- } else {
- IRB_Dtor.CreateCall(AsanUnregisterGlobals,
- {IRB.CreatePointerCast(AllGlobals, IntptrTy),
- ConstantInt::get(IntptrTy, n)});
- }
-
- appendToGlobalDtors(M, AsanDtorFunction, kAsanCtorAndDtorPriority);
-
DEBUG(dbgs() << M);
return true;
}
generated by cgit v1.2.3 (git 2.25.1) at 2025-08-06 12:53:12 +0000