//
//===----------------------------------------------------------------------===//
-#define DEBUG_TYPE "stack-protector"
+#include "llvm/CodeGen/StackProtector.h"
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/Analysis/BranchProbabilityInfo.h"
+#include "llvm/Analysis/ValueTracking.h"
+#include "llvm/CodeGen/Analysis.h"
#include "llvm/CodeGen/Passes.h"
-#include "llvm/Constants.h"
-#include "llvm/DerivedTypes.h"
-#include "llvm/Function.h"
-#include "llvm/Instructions.h"
-#include "llvm/Intrinsics.h"
-#include "llvm/Module.h"
-#include "llvm/Pass.h"
+#include "llvm/IR/Attributes.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/DerivedTypes.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/GlobalValue.h"
+#include "llvm/IR/GlobalVariable.h"
+#include "llvm/IR/IRBuilder.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/IntrinsicInst.h"
+#include "llvm/IR/Intrinsics.h"
+#include "llvm/IR/MDBuilder.h"
+#include "llvm/IR/Module.h"
#include "llvm/Support/CommandLine.h"
-#include "llvm/Target/TargetData.h"
-#include "llvm/Target/TargetLowering.h"
+#include "llvm/Target/TargetSubtargetInfo.h"
+#include <cstdlib>
using namespace llvm;
-// SSPBufferSize - The lower bound for a buffer to be considered for stack
-// smashing protection.
-static cl::opt<unsigned>
-SSPBufferSize("stack-protector-buffer-size", cl::init(8),
- cl::desc("The lower bound for a buffer to be considered for "
- "stack smashing protection."));
-
-namespace {
- class VISIBILITY_HIDDEN StackProtector : public FunctionPass {
- /// Level - The level of stack protection.
- SSP::StackProtectorLevel Level;
-
- /// TLI - Keep a pointer of a TargetLowering to consult for determining
- /// target type sizes.
- const TargetLowering *TLI;
-
- Function *F;
- Module *M;
-
- /// InsertStackProtectors - Insert code into the prologue and epilogue of
- /// the function.
- ///
- /// - The prologue code loads and stores the stack guard onto the stack.
- /// - The epilogue checks the value stored in the prologue against the
- /// original value. It calls __stack_chk_fail if they differ.
- bool InsertStackProtectors();
-
- /// CreateFailBB - Create a basic block to jump to when the stack protector
- /// check fails.
- BasicBlock *CreateFailBB();
-
- /// RequiresStackProtector - Check whether or not this function needs a
- /// stack protector based upon the stack protector level.
- bool RequiresStackProtector() const;
- public:
- static char ID; // Pass identification, replacement for typeid.
- StackProtector() : FunctionPass(&ID), Level(SSP::OFF), TLI(0) {}
- StackProtector(SSP::StackProtectorLevel lvl, const TargetLowering *tli)
- : FunctionPass(&ID), Level(lvl), TLI(tli) {}
-
- virtual bool runOnFunction(Function &Fn);
- };
-} // end anonymous namespace
+#define DEBUG_TYPE "stack-protector"
+
+STATISTIC(NumFunProtected, "Number of functions protected");
+STATISTIC(NumAddrTaken, "Number of local variables that have their address"
+ " taken.");
+
+static cl::opt<bool> EnableSelectionDAGSP("enable-selectiondag-sp",
+ cl::init(true), cl::Hidden);
char StackProtector::ID = 0;
-static RegisterPass<StackProtector>
-X("stack-protector", "Insert stack protectors");
+INITIALIZE_PASS(StackProtector, "stack-protector", "Insert stack protectors",
+ false, true)
+
+FunctionPass *llvm::createStackProtectorPass(const TargetMachine *TM) {
+ return new StackProtector(TM);
+}
-FunctionPass *llvm::createStackProtectorPass(SSP::StackProtectorLevel lvl,
- const TargetLowering *tli) {
- return new StackProtector(lvl, tli);
+StackProtector::SSPLayoutKind
+StackProtector::getSSPLayout(const AllocaInst *AI) const {
+ return AI ? Layout.lookup(AI) : SSPLK_None;
+}
+
+void StackProtector::adjustForColoring(const AllocaInst *From,
+ const AllocaInst *To) {
+ // When coloring replaces one alloca with another, transfer the SSPLayoutKind
+ // tag from the remapped to the target alloca. The remapped alloca should
+ // have a size smaller than or equal to the replacement alloca.
+ SSPLayoutMap::iterator I = Layout.find(From);
+ if (I != Layout.end()) {
+ SSPLayoutKind Kind = I->second;
+ Layout.erase(I);
+
+ // Transfer the tag, but make sure that SSPLK_AddrOf does not overwrite
+ // SSPLK_SmallArray or SSPLK_LargeArray, and make sure that
+ // SSPLK_SmallArray does not overwrite SSPLK_LargeArray.
+ I = Layout.find(To);
+ if (I == Layout.end())
+ Layout.insert(std::make_pair(To, Kind));
+ else if (I->second != SSPLK_LargeArray && Kind != SSPLK_AddrOf)
+ I->second = Kind;
+ }
}
bool StackProtector::runOnFunction(Function &Fn) {
F = &Fn;
M = F->getParent();
+ DominatorTreeWrapperPass *DTWP =
+ getAnalysisIfAvailable<DominatorTreeWrapperPass>();
+ DT = DTWP ? &DTWP->getDomTree() : nullptr;
+ TLI = TM->getSubtargetImpl(Fn)->getTargetLowering();
- if (!RequiresStackProtector()) return false;
-
+ Attribute Attr = Fn.getFnAttribute("stack-protector-buffer-size");
+ if (Attr.isStringAttribute() &&
+ Attr.getValueAsString().getAsInteger(10, SSPBufferSize))
+ return false; // Invalid integer string
+
+ if (!RequiresStackProtector())
+ return false;
+
+ ++NumFunProtected;
return InsertStackProtectors();
}
+/// \param [out] IsLarge is set to true if a protectable array is found and
+/// it is "large" ( >= ssp-buffer-size). In the case of a structure with
+/// multiple arrays, this gets set if any of them is large.
+bool StackProtector::ContainsProtectableArray(Type *Ty, bool &IsLarge,
+ bool Strong,
+ bool InStruct) const {
+ if (!Ty)
+ return false;
+ if (ArrayType *AT = dyn_cast<ArrayType>(Ty)) {
+ if (!AT->getElementType()->isIntegerTy(8)) {
+ // If we're on a non-Darwin platform or we're inside of a structure, don't
+ // add stack protectors unless the array is a character array.
+ // However, in strong mode any array, regardless of type and size,
+ // triggers a protector.
+ if (!Strong && (InStruct || !Trip.isOSDarwin()))
+ return false;
+ }
+
+ // If an array has more than SSPBufferSize bytes of allocated space, then we
+ // emit stack protectors.
+ if (SSPBufferSize <= M->getDataLayout().getTypeAllocSize(AT)) {
+ IsLarge = true;
+ return true;
+ }
+
+ if (Strong)
+ // Require a protector for all arrays in strong mode
+ return true;
+ }
+
+ const StructType *ST = dyn_cast<StructType>(Ty);
+ if (!ST)
+ return false;
+
+ bool NeedsProtector = false;
+ for (StructType::element_iterator I = ST->element_begin(),
+ E = ST->element_end();
+ I != E; ++I)
+ if (ContainsProtectableArray(*I, IsLarge, Strong, true)) {
+ // If the element is a protectable array and is large (>= SSPBufferSize)
+ // then we are done. If the protectable array is not large, then
+ // keep looking in case a subsequent element is a large array.
+ if (IsLarge)
+ return true;
+ NeedsProtector = true;
+ }
+
+ return NeedsProtector;
+}
+
+bool StackProtector::HasAddressTaken(const Instruction *AI) {
+ for (const User *U : AI->users()) {
+ if (const StoreInst *SI = dyn_cast<StoreInst>(U)) {
+ if (AI == SI->getValueOperand())
+ return true;
+ } else if (const PtrToIntInst *SI = dyn_cast<PtrToIntInst>(U)) {
+ if (AI == SI->getOperand(0))
+ return true;
+ } else if (isa<CallInst>(U)) {
+ return true;
+ } else if (isa<InvokeInst>(U)) {
+ return true;
+ } else if (const SelectInst *SI = dyn_cast<SelectInst>(U)) {
+ if (HasAddressTaken(SI))
+ return true;
+ } else if (const PHINode *PN = dyn_cast<PHINode>(U)) {
+ // Keep track of what PHI nodes we have already visited to ensure
+ // they are only visited once.
+ if (VisitedPHIs.insert(PN).second)
+ if (HasAddressTaken(PN))
+ return true;
+ } else if (const GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(U)) {
+ if (HasAddressTaken(GEP))
+ return true;
+ } else if (const BitCastInst *BI = dyn_cast<BitCastInst>(U)) {
+ if (HasAddressTaken(BI))
+ return true;
+ }
+ }
+ return false;
+}
+
+/// \brief Check whether or not this function needs a stack protector based
+/// upon the stack protector level.
+///
+/// We use two heuristics: a standard (ssp) and strong (sspstrong).
+/// The standard heuristic which will add a guard variable to functions that
+/// call alloca with a either a variable size or a size >= SSPBufferSize,
+/// functions with character buffers larger than SSPBufferSize, and functions
+/// with aggregates containing character buffers larger than SSPBufferSize. The
+/// strong heuristic will add a guard variables to functions that call alloca
+/// regardless of size, functions with any buffer regardless of type and size,
+/// functions with aggregates that contain any buffer regardless of type and
+/// size, and functions that contain stack-based variables that have had their
+/// address taken.
+bool StackProtector::RequiresStackProtector() {
+ bool Strong = false;
+ bool NeedsProtector = false;
+ if (F->hasFnAttribute(Attribute::StackProtectReq)) {
+ NeedsProtector = true;
+ Strong = true; // Use the same heuristic as strong to determine SSPLayout
+ } else if (F->hasFnAttribute(Attribute::StackProtectStrong))
+ Strong = true;
+ else if (!F->hasFnAttribute(Attribute::StackProtect))
+ return false;
+
+ for (const BasicBlock &BB : *F) {
+ for (const Instruction &I : BB) {
+ if (const AllocaInst *AI = dyn_cast<AllocaInst>(&I)) {
+ if (AI->isArrayAllocation()) {
+ // SSP-Strong: Enable protectors for any call to alloca, regardless
+ // of size.
+ if (Strong)
+ return true;
+
+ if (const auto *CI = dyn_cast<ConstantInt>(AI->getArraySize())) {
+ if (CI->getLimitedValue(SSPBufferSize) >= SSPBufferSize) {
+ // A call to alloca with size >= SSPBufferSize requires
+ // stack protectors.
+ Layout.insert(std::make_pair(AI, SSPLK_LargeArray));
+ NeedsProtector = true;
+ } else if (Strong) {
+ // Require protectors for all alloca calls in strong mode.
+ Layout.insert(std::make_pair(AI, SSPLK_SmallArray));
+ NeedsProtector = true;
+ }
+ } else {
+ // A call to alloca with a variable size requires protectors.
+ Layout.insert(std::make_pair(AI, SSPLK_LargeArray));
+ NeedsProtector = true;
+ }
+ continue;
+ }
+
+ bool IsLarge = false;
+ if (ContainsProtectableArray(AI->getAllocatedType(), IsLarge, Strong)) {
+ Layout.insert(std::make_pair(AI, IsLarge ? SSPLK_LargeArray
+ : SSPLK_SmallArray));
+ NeedsProtector = true;
+ continue;
+ }
+
+ if (Strong && HasAddressTaken(AI)) {
+ ++NumAddrTaken;
+ Layout.insert(std::make_pair(AI, SSPLK_AddrOf));
+ NeedsProtector = true;
+ }
+ }
+ }
+ }
+
+ return NeedsProtector;
+}
+
+static bool InstructionWillNotHaveChain(const Instruction *I) {
+ return !I->mayHaveSideEffects() && !I->mayReadFromMemory() &&
+ isSafeToSpeculativelyExecute(I);
+}
+
+/// Identify if RI has a previous instruction in the "Tail Position" and return
+/// it. Otherwise return 0.
+///
+/// This is based off of the code in llvm::isInTailCallPosition. The difference
+/// is that it inverts the first part of llvm::isInTailCallPosition since
+/// isInTailCallPosition is checking if a call is in a tail call position, and
+/// we are searching for an unknown tail call that might be in the tail call
+/// position. Once we find the call though, the code uses the same refactored
+/// code, returnTypeIsEligibleForTailCall.
+static CallInst *FindPotentialTailCall(BasicBlock *BB, ReturnInst *RI,
+ const TargetLoweringBase *TLI) {
+ // Establish a reasonable upper bound on the maximum amount of instructions we
+ // will look through to find a tail call.
+ unsigned SearchCounter = 0;
+ const unsigned MaxSearch = 4;
+ bool NoInterposingChain = true;
+
+ for (BasicBlock::reverse_iterator I = std::next(BB->rbegin()), E = BB->rend();
+ I != E && SearchCounter < MaxSearch; ++I) {
+ Instruction *Inst = &*I;
+
+ // Skip over debug intrinsics and do not allow them to affect our MaxSearch
+ // counter.
+ if (isa<DbgInfoIntrinsic>(Inst))
+ continue;
+
+ // If we find a call and the following conditions are satisifed, then we
+ // have found a tail call that satisfies at least the target independent
+ // requirements of a tail call:
+ //
+ // 1. The call site has the tail marker.
+ //
+ // 2. The call site either will not cause the creation of a chain or if a
+ // chain is necessary there are no instructions in between the callsite and
+ // the call which would create an interposing chain.
+ //
+ // 3. The return type of the function does not impede tail call
+ // optimization.
+ if (CallInst *CI = dyn_cast<CallInst>(Inst)) {
+ if (CI->isTailCall() &&
+ (InstructionWillNotHaveChain(CI) || NoInterposingChain) &&
+ returnTypeIsEligibleForTailCall(BB->getParent(), CI, RI, *TLI))
+ return CI;
+ }
+
+ // If we did not find a call see if we have an instruction that may create
+ // an interposing chain.
+ NoInterposingChain =
+ NoInterposingChain && InstructionWillNotHaveChain(Inst);
+
+ // Increment max search.
+ SearchCounter++;
+ }
+
+ return nullptr;
+}
+
+/// Insert code into the entry block that stores the __stack_chk_guard
+/// variable onto the stack:
+///
+/// entry:
+/// StackGuardSlot = alloca i8*
+/// StackGuard = load __stack_chk_guard
+/// call void @llvm.stackprotect.create(StackGuard, StackGuardSlot)
+///
+/// Returns true if the platform/triple supports the stackprotectorcreate pseudo
+/// node.
+static bool CreatePrologue(Function *F, Module *M, ReturnInst *RI,
+ const TargetLoweringBase *TLI, const Triple &TT,
+ AllocaInst *&AI, Value *&StackGuardVar) {
+ bool SupportsSelectionDAGSP = false;
+ PointerType *PtrTy = Type::getInt8PtrTy(RI->getContext());
+ unsigned AddressSpace, Offset;
+ if (TLI->getStackCookieLocation(AddressSpace, Offset)) {
+ Constant *OffsetVal =
+ ConstantInt::get(Type::getInt32Ty(RI->getContext()), Offset);
+
+ StackGuardVar =
+ ConstantExpr::getIntToPtr(OffsetVal, PointerType::get(PtrTy,
+ AddressSpace));
+ } else if (TT.isOSOpenBSD()) {
+ StackGuardVar = M->getOrInsertGlobal("__guard_local", PtrTy);
+ cast<GlobalValue>(StackGuardVar)
+ ->setVisibility(GlobalValue::HiddenVisibility);
+ } else {
+ SupportsSelectionDAGSP = true;
+ StackGuardVar = M->getOrInsertGlobal("__stack_chk_guard", PtrTy);
+ }
+
+ IRBuilder<> B(&F->getEntryBlock().front());
+ AI = B.CreateAlloca(PtrTy, nullptr, "StackGuardSlot");
+ LoadInst *LI = B.CreateLoad(StackGuardVar, "StackGuard");
+ B.CreateCall(Intrinsic::getDeclaration(M, Intrinsic::stackprotector),
+ {LI, AI});
+
+ return SupportsSelectionDAGSP;
+}
+
/// InsertStackProtectors - Insert code into the prologue and epilogue of the
/// function.
///
/// - The epilogue checks the value stored in the prologue against the original
/// value. It calls __stack_chk_fail if they differ.
bool StackProtector::InsertStackProtectors() {
- // Loop through the basic blocks that have return instructions. Convert this:
- //
- // return:
- // ...
- // ret ...
- //
- // into this:
- //
- // return:
- // ...
- // %1 = load __stack_chk_guard
- // %2 = load <stored stack guard>
- // %3 = cmp i1 %1, %2
- // br i1 %3, label %SP_return, label %CallStackCheckFailBlk
- //
- // SP_return:
- // ret ...
- //
- // CallStackCheckFailBlk:
- // call void @__stack_chk_fail()
- // unreachable
- //
- BasicBlock *FailBB = 0; // The basic block to jump to if check fails.
- AllocaInst *AI = 0; // Place on stack that stores the stack guard.
- Constant *StackGuardVar = 0; // The stack guard variable.
-
- for (Function::iterator I = F->begin(), E = F->end(); I != E; ) {
- BasicBlock *BB = I;
-
- if (ReturnInst *RI = dyn_cast<ReturnInst>(BB->getTerminator())) {
- if (!FailBB) {
- // Insert code into the entry block that stores the __stack_chk_guard
- // variable onto the stack.
- PointerType *PtrTy = PointerType::getUnqual(Type::Int8Ty);
- StackGuardVar = M->getOrInsertGlobal("__stack_chk_guard", PtrTy);
-
- BasicBlock &Entry = F->getEntryBlock();
- Instruction *InsPt = &Entry.front();
-
- AI = new AllocaInst(PtrTy, "StackGuardSlot", InsPt);
- LoadInst *LI = new LoadInst(StackGuardVar, "StackGuard", false, InsPt);
-
- Value *Args[] = { LI, AI };
- CallInst::
- Create(Intrinsic::getDeclaration(M, Intrinsic::stackprotector_create),
- &Args[0], array_endof(Args), "", InsPt);
-
- // Create the basic block to jump to when the guard check fails.
- FailBB = CreateFailBB();
+ bool HasPrologue = false;
+ bool SupportsSelectionDAGSP =
+ EnableSelectionDAGSP && !TM->Options.EnableFastISel;
+ AllocaInst *AI = nullptr; // Place on stack that stores the stack guard.
+ Value *StackGuardVar = nullptr; // The stack guard variable.
+
+ for (Function::iterator I = F->begin(), E = F->end(); I != E;) {
+ BasicBlock *BB = I++;
+ ReturnInst *RI = dyn_cast<ReturnInst>(BB->getTerminator());
+ if (!RI)
+ continue;
+
+ if (!HasPrologue) {
+ HasPrologue = true;
+ SupportsSelectionDAGSP &=
+ CreatePrologue(F, M, RI, TLI, Trip, AI, StackGuardVar);
+ }
+
+ if (SupportsSelectionDAGSP) {
+ // Since we have a potential tail call, insert the special stack check
+ // intrinsic.
+ Instruction *InsertionPt = nullptr;
+ if (CallInst *CI = FindPotentialTailCall(BB, RI, TLI)) {
+ InsertionPt = CI;
+ } else {
+ InsertionPt = RI;
+ // At this point we know that BB has a return statement so it *DOES*
+ // have a terminator.
+ assert(InsertionPt != nullptr &&
+ "BB must have a terminator instruction at this point.");
}
- ++I; // Skip to the next block so that we don't resplit the return block.
+ Function *Intrinsic =
+ Intrinsic::getDeclaration(M, Intrinsic::stackprotectorcheck);
+ CallInst::Create(Intrinsic, StackGuardVar, "", InsertionPt);
+ } else {
+ // If we do not support SelectionDAG based tail calls, generate IR level
+ // tail calls.
+ //
+ // For each block with a return instruction, convert this:
+ //
+ // return:
+ // ...
+ // ret ...
+ //
+ // into this:
+ //
+ // return:
+ // ...
+ // %1 = load __stack_chk_guard
+ // %2 = load StackGuardSlot
+ // %3 = cmp i1 %1, %2
+ // br i1 %3, label %SP_return, label %CallStackCheckFailBlk
+ //
+ // SP_return:
+ // ret ...
+ //
+ // CallStackCheckFailBlk:
+ // call void @__stack_chk_fail()
+ // unreachable
+
+ // Create the FailBB. We duplicate the BB every time since the MI tail
+ // merge pass will merge together all of the various BB into one including
+ // fail BB generated by the stack protector pseudo instruction.
+ BasicBlock *FailBB = CreateFailBB();
// Split the basic block before the return instruction.
BasicBlock *NewBB = BB->splitBasicBlock(RI, "SP_return");
+ // Update the dominator tree if we need to.
+ if (DT && DT->isReachableFromEntry(BB)) {
+ DT->addNewBlock(NewBB, BB);
+ DT->addNewBlock(FailBB, BB);
+ }
+
+ // Remove default branch instruction to the new BB.
+ BB->getTerminator()->eraseFromParent();
+
// Move the newly created basic block to the point right after the old
// basic block so that it's in the "fall through" position.
- NewBB->removeFromParent();
- F->getBasicBlockList().insert(I, NewBB);
+ NewBB->moveAfter(BB);
// Generate the stack protector instructions in the old basic block.
- LoadInst *LI1 = new LoadInst(StackGuardVar, "", false, BB);
- CallInst *CI = CallInst::
- Create(Intrinsic::getDeclaration(M, Intrinsic::stackprotector_check),
- AI, "", BB);
- ICmpInst *Cmp = new ICmpInst(CmpInst::ICMP_EQ, CI, LI1, "", BB);
- BranchInst::Create(NewBB, FailBB, Cmp, BB);
- } else {
- ++I;
+ IRBuilder<> B(BB);
+ LoadInst *LI1 = B.CreateLoad(StackGuardVar);
+ LoadInst *LI2 = B.CreateLoad(AI);
+ Value *Cmp = B.CreateICmpEQ(LI1, LI2);
+ unsigned SuccessWeight =
+ BranchProbabilityInfo::getBranchWeightStackProtector(true);
+ unsigned FailureWeight =
+ BranchProbabilityInfo::getBranchWeightStackProtector(false);
+ MDNode *Weights = MDBuilder(F->getContext())
+ .createBranchWeights(SuccessWeight, FailureWeight);
+ B.CreateCondBr(Cmp, NewBB, FailBB, Weights);
}
}
- // Return if we didn't modify any basic blocks. I.e., there are no return
+ // Return if we didn't modify any basic blocks. i.e., there are no return
// statements in the function.
- if (!FailBB) return false;
+ if (!HasPrologue)
+ return false;
return true;
}
/// CreateFailBB - Create a basic block to jump to when the stack protector
/// check fails.
BasicBlock *StackProtector::CreateFailBB() {
- BasicBlock *FailBB = BasicBlock::Create("CallStackCheckFailBlk", F);
- Constant *StackChkFail =
- M->getOrInsertFunction("__stack_chk_fail", Type::VoidTy, NULL);
- CallInst::Create(StackChkFail, "", FailBB);
- new UnreachableInst(FailBB);
- return FailBB;
-}
-
-/// RequiresStackProtector - Check whether or not this function needs a stack
-/// protector based upon the stack protector level. The heuristic we use is to
-/// add a guard variable to functions that call alloca, and functions with
-/// buffers larger than 8 bytes.
-bool StackProtector::RequiresStackProtector() const {
- switch (Level) {
- default: return false;
- case SSP::ALL: return true;
- case SSP::SOME: {
- const TargetData *TD = TLI->getTargetData();
-
- for (Function::iterator I = F->begin(), E = F->end(); I != E; ++I) {
- BasicBlock *BB = I;
-
- for (BasicBlock::iterator
- II = BB->begin(), IE = BB->end(); II != IE; ++II)
- if (AllocaInst *AI = dyn_cast<AllocaInst>(II)) {
- if (AI->isArrayAllocation())
- // This is a call to alloca with a variable size. Emit stack
- // protectors.
- return true;
-
- if (const ArrayType *AT = dyn_cast<ArrayType>(AI->getAllocatedType()))
- // If an array has more than 8 bytes of allocated space, then we
- // emit stack protectors.
- if (SSPBufferSize <= TD->getABITypeSize(AT))
- return true;
- }
- }
-
- return false;
- }
+ LLVMContext &Context = F->getContext();
+ BasicBlock *FailBB = BasicBlock::Create(Context, "CallStackCheckFailBlk", F);
+ IRBuilder<> B(FailBB);
+ if (Trip.isOSOpenBSD()) {
+ Constant *StackChkFail =
+ M->getOrInsertFunction("__stack_smash_handler",
+ Type::getVoidTy(Context),
+ Type::getInt8PtrTy(Context), nullptr);
+
+ B.CreateCall(StackChkFail, B.CreateGlobalStringPtr(F->getName(), "SSH"));
+ } else {
+ Constant *StackChkFail =
+ M->getOrInsertFunction("__stack_chk_fail", Type::getVoidTy(Context),
+ nullptr);
+ B.CreateCall(StackChkFail, {});
}
+ B.CreateUnreachable();
+ return FailBB;
}
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