//
//===----------------------------------------------------------------------===//
-#define DEBUG_TYPE "shadowstackgc"
#include "llvm/CodeGen/GCs.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/CodeGen/GCStrategy.h"
-#include "llvm/IntrinsicInst.h"
-#include "llvm/Module.h"
-#include "llvm/Support/IRBuilder.h"
+#include "llvm/IR/CallSite.h"
+#include "llvm/IR/IRBuilder.h"
+#include "llvm/IR/IntrinsicInst.h"
+#include "llvm/IR/Module.h"
using namespace llvm;
+#define DEBUG_TYPE "shadowstackgc"
+
namespace {
class ShadowStackGC : public GCStrategy {
/// StackEntryTy - Abstract type of a link in the shadow stack.
///
- const StructType *StackEntryTy;
+ StructType *StackEntryTy;
+ StructType *FrameMapTy;
/// Roots - GC roots in the current function. Each is a pair of the
/// intrinsic call and its corresponding alloca.
public:
ShadowStackGC();
- bool initializeCustomLowering(Module &M);
- bool performCustomLowering(Function &F);
+ bool initializeCustomLowering(Module &M) override;
+ bool performCustomLowering(Function &F) override;
private:
bool IsNullValue(Value *V);
Constant *GetFrameMap(Function &F);
- const Type* GetConcreteStackEntryType(Function &F);
+ Type* GetConcreteStackEntryType(Function &F);
void CollectRoots(Function &F);
static GetElementPtrInst *CreateGEP(LLVMContext &Context,
IRBuilder<> &B, Value *BasePtr,
IRBuilder<> *Next() {
switch (State) {
default:
- return 0;
+ return nullptr;
case 0:
StateBB = F.begin();
State = 1;
case 1:
- // Find all 'return' and 'unwind' instructions.
+ // Find all 'return', 'resume', and 'unwind' instructions.
while (StateBB != StateE) {
BasicBlock *CurBB = StateBB++;
- // Branches and invokes do not escape, only unwind and return do.
+ // Branches and invokes do not escape, only unwind, resume, and return
+ // do.
TerminatorInst *TI = CurBB->getTerminator();
- if (!isa<UnwindInst>(TI) && !isa<ReturnInst>(TI))
+ if (!isa<ReturnInst>(TI) && !isa<ResumeInst>(TI))
continue;
Builder.SetInsertPoint(TI->getParent(), TI);
Calls.push_back(CI);
if (Calls.empty())
- return 0;
+ return nullptr;
// Create a cleanup block.
- BasicBlock *CleanupBB = BasicBlock::Create(F.getContext(),
- CleanupBBName, &F);
- UnwindInst *UI = new UnwindInst(F.getContext(), CleanupBB);
+ LLVMContext &C = F.getContext();
+ BasicBlock *CleanupBB = BasicBlock::Create(C, CleanupBBName, &F);
+ Type *ExnTy = StructType::get(Type::getInt8PtrTy(C),
+ Type::getInt32Ty(C), NULL);
+ Constant *PersFn =
+ F.getParent()->
+ getOrInsertFunction("__gcc_personality_v0",
+ FunctionType::get(Type::getInt32Ty(C), true));
+ LandingPadInst *LPad = LandingPadInst::Create(ExnTy, PersFn, 1,
+ "cleanup.lpad",
+ CleanupBB);
+ LPad->setCleanup(true);
+ ResumeInst *RI = ResumeInst::Create(LPad, CleanupBB);
// Transform the 'call' instructions into 'invoke's branching to the
// cleanup block. Go in reverse order to make prettier BB names.
// Create a new invoke instruction.
Args.clear();
- Args.append(CI->op_begin(), CI->op_end() - 1);
+ CallSite CS(CI);
+ Args.append(CS.arg_begin(), CS.arg_end());
InvokeInst *II = InvokeInst::Create(CI->getCalledValue(),
NewBB, CleanupBB,
- Args.begin(), Args.end(),
- CI->getName(), CallBB);
+ Args, CI->getName(), CallBB);
II->setCallingConv(CI->getCallingConv());
II->setAttributes(CI->getAttributes());
CI->replaceAllUsesWith(II);
delete CI;
}
- Builder.SetInsertPoint(UI->getParent(), UI);
+ Builder.SetInsertPoint(RI->getParent(), RI);
return &Builder;
}
}
void llvm::linkShadowStackGC() { }
-ShadowStackGC::ShadowStackGC() : Head(0), StackEntryTy(0) {
+ShadowStackGC::ShadowStackGC() : Head(nullptr), StackEntryTy(nullptr) {
InitRoots = true;
CustomRoots = true;
}
Constant *ShadowStackGC::GetFrameMap(Function &F) {
// doInitialization creates the abstract type of this value.
- const Type *VoidPtr = Type::getInt8PtrTy(F.getContext());
+ Type *VoidPtr = Type::getInt8PtrTy(F.getContext());
// Truncate the ShadowStackDescriptor if some metadata is null.
unsigned NumMeta = 0;
- SmallVector<Constant*,16> Metadata;
+ SmallVector<Constant*, 16> Metadata;
for (unsigned I = 0; I != Roots.size(); ++I) {
- Constant *C = cast<Constant>(Roots[I].first->getOperand(1));
+ Constant *C = cast<Constant>(Roots[I].first->getArgOperand(1));
if (!C->isNullValue())
NumMeta = I + 1;
Metadata.push_back(ConstantExpr::getBitCast(C, VoidPtr));
}
+ Metadata.resize(NumMeta);
+ Type *Int32Ty = Type::getInt32Ty(F.getContext());
+
Constant *BaseElts[] = {
- ConstantInt::get(Type::getInt32Ty(F.getContext()), Roots.size(), false),
- ConstantInt::get(Type::getInt32Ty(F.getContext()), NumMeta, false),
+ ConstantInt::get(Int32Ty, Roots.size(), false),
+ ConstantInt::get(Int32Ty, NumMeta, false),
};
Constant *DescriptorElts[] = {
- ConstantStruct::get(F.getContext(), BaseElts, 2, false),
- ConstantArray::get(ArrayType::get(VoidPtr, NumMeta),
- Metadata.begin(), NumMeta)
+ ConstantStruct::get(FrameMapTy, BaseElts),
+ ConstantArray::get(ArrayType::get(VoidPtr, NumMeta), Metadata)
};
- Constant *FrameMap = ConstantStruct::get(F.getContext(), DescriptorElts, 2,
- false);
-
- std::string TypeName("gc_map.");
- TypeName += utostr(NumMeta);
- F.getParent()->addTypeName(TypeName, FrameMap->getType());
+ Type *EltTys[] = { DescriptorElts[0]->getType(),DescriptorElts[1]->getType()};
+ StructType *STy = StructType::create(EltTys, "gc_map."+utostr(NumMeta));
+
+ Constant *FrameMap = ConstantStruct::get(STy, DescriptorElts);
// FIXME: Is this actually dangerous as WritingAnLLVMPass.html claims? Seems
// that, short of multithreaded LLVM, it should be safe; all that is
ConstantInt::get(Type::getInt32Ty(F.getContext()), 0),
ConstantInt::get(Type::getInt32Ty(F.getContext()), 0)
};
- return ConstantExpr::getGetElementPtr(GV, GEPIndices, 2);
+ return ConstantExpr::getGetElementPtr(GV, GEPIndices);
}
-const Type* ShadowStackGC::GetConcreteStackEntryType(Function &F) {
+Type* ShadowStackGC::GetConcreteStackEntryType(Function &F) {
// doInitialization creates the generic version of this type.
- std::vector<const Type*> EltTys;
+ std::vector<Type*> EltTys;
EltTys.push_back(StackEntryTy);
for (size_t I = 0; I != Roots.size(); I++)
EltTys.push_back(Roots[I].second->getAllocatedType());
- Type *Ty = StructType::get(F.getContext(), EltTys);
-
- std::string TypeName("gc_stackentry.");
- TypeName += F.getName();
- F.getParent()->addTypeName(TypeName, Ty);
-
- return Ty;
+
+ return StructType::create(EltTys, "gc_stackentry."+F.getName().str());
}
/// doInitialization - If this module uses the GC intrinsics, find them now. If
// int32_t NumMeta; // Number of metadata descriptors. May be < NumRoots.
// void *Meta[]; // May be absent for roots without metadata.
// };
- std::vector<const Type*> EltTys;
+ std::vector<Type*> EltTys;
// 32 bits is ok up to a 32GB stack frame. :)
EltTys.push_back(Type::getInt32Ty(M.getContext()));
// Specifies length of variable length array.
EltTys.push_back(Type::getInt32Ty(M.getContext()));
- StructType *FrameMapTy = StructType::get(M.getContext(), EltTys);
- M.addTypeName("gc_map", FrameMapTy);
+ FrameMapTy = StructType::create(EltTys, "gc_map");
PointerType *FrameMapPtrTy = PointerType::getUnqual(FrameMapTy);
// struct StackEntry {
// FrameMap *Map; // Pointer to constant FrameMap.
// void *Roots[]; // Stack roots (in-place array, so we pretend).
// };
- OpaqueType *RecursiveTy = OpaqueType::get(M.getContext());
-
+
+ StackEntryTy = StructType::create(M.getContext(), "gc_stackentry");
+
EltTys.clear();
- EltTys.push_back(PointerType::getUnqual(RecursiveTy));
+ EltTys.push_back(PointerType::getUnqual(StackEntryTy));
EltTys.push_back(FrameMapPtrTy);
- PATypeHolder LinkTyH = StructType::get(M.getContext(), EltTys);
-
- RecursiveTy->refineAbstractTypeTo(LinkTyH.get());
- StackEntryTy = cast<StructType>(LinkTyH.get());
- const PointerType *StackEntryPtrTy = PointerType::getUnqual(StackEntryTy);
- M.addTypeName("gc_stackentry", LinkTyH.get()); // FIXME: Is this safe from
- // a FunctionPass?
+ StackEntryTy->setBody(EltTys);
+ PointerType *StackEntryPtrTy = PointerType::getUnqual(StackEntryTy);
// Get the root chain if it already exists.
Head = M.getGlobalVariable("llvm_gc_root_chain");
assert(Roots.empty() && "Not cleaned up?");
- SmallVector<std::pair<CallInst*, AllocaInst*>,16> MetaRoots;
+ SmallVector<std::pair<CallInst*, AllocaInst*>, 16> MetaRoots;
for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
for (BasicBlock::iterator II = BB->begin(), E = BB->end(); II != E;)
if (Function *F = CI->getCalledFunction())
if (F->getIntrinsicID() == Intrinsic::gcroot) {
std::pair<CallInst*, AllocaInst*> Pair = std::make_pair(
- CI, cast<AllocaInst>(CI->getOperand(0)->stripPointerCasts()));
- if (IsNullValue(CI->getOperand(1)))
+ CI, cast<AllocaInst>(CI->getArgOperand(0)->stripPointerCasts()));
+ if (IsNullValue(CI->getArgOperand(1)))
Roots.push_back(Pair);
else
MetaRoots.push_back(Pair);
Value *Indices[] = { ConstantInt::get(Type::getInt32Ty(Context), 0),
ConstantInt::get(Type::getInt32Ty(Context), Idx),
ConstantInt::get(Type::getInt32Ty(Context), Idx2) };
- Value* Val = B.CreateGEP(BasePtr, Indices, Indices + 3, Name);
+ Value* Val = B.CreateGEP(BasePtr, Indices, Name);
assert(isa<GetElementPtrInst>(Val) && "Unexpected folded constant");
int Idx, const char *Name) {
Value *Indices[] = { ConstantInt::get(Type::getInt32Ty(Context), 0),
ConstantInt::get(Type::getInt32Ty(Context), Idx) };
- Value *Val = B.CreateGEP(BasePtr, Indices, Indices + 2, Name);
+ Value *Val = B.CreateGEP(BasePtr, Indices, Name);
assert(isa<GetElementPtrInst>(Val) && "Unexpected folded constant");
// Build the constant map and figure the type of the shadow stack entry.
Value *FrameMap = GetFrameMap(F);
- const Type *ConcreteStackEntryTy = GetConcreteStackEntryType(F);
+ Type *ConcreteStackEntryTy = GetConcreteStackEntryType(F);
// Build the shadow stack entry at the very start of the function.
BasicBlock::iterator IP = F.getEntryBlock().begin();
IRBuilder<> AtEntry(IP->getParent(), IP);
- Instruction *StackEntry = AtEntry.CreateAlloca(ConcreteStackEntryTy, 0,
- "gc_frame");
+ Instruction *StackEntry = AtEntry.CreateAlloca(ConcreteStackEntryTy, nullptr,
+ "gc_frame");
while (isa<AllocaInst>(IP)) ++IP;
AtEntry.SetInsertPoint(IP->getParent(), IP);
Instruction *CurrentHead = AtEntry.CreateLoad(Head, "gc_currhead");
Instruction *EntryMapPtr = CreateGEP(Context, AtEntry, StackEntry,
0,1,"gc_frame.map");
- AtEntry.CreateStore(FrameMap, EntryMapPtr);
+ AtEntry.CreateStore(FrameMap, EntryMapPtr);
// After all the allocas...
for (unsigned I = 0, E = Roots.size(); I != E; ++I) {