X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FCodeGen%2FStackProtector.cpp;h=e478f31d54552f33eba9ece7c6cd26a1c864fff5;hb=9f92467a5348cecdc5513ba9805add6c67e504c2;hp=d2d87b2c961b0f9c814d4190bd3f119897b28980;hpb=4598b40ce62dceb5ff96bbb7caeebd1ca57ae3fe;p=oota-llvm.git diff --git a/lib/CodeGen/StackProtector.cpp b/lib/CodeGen/StackProtector.cpp index d2d87b2c961..e478f31d545 100644 --- a/lib/CodeGen/StackProtector.cpp +++ b/lib/CodeGen/StackProtector.cpp @@ -14,14 +14,12 @@ // //===----------------------------------------------------------------------===// -#define DEBUG_TYPE "stack-protector" #include "llvm/CodeGen/StackProtector.h" -#include "llvm/CodeGen/Analysis.h" -#include "llvm/CodeGen/Passes.h" #include "llvm/ADT/SmallPtrSet.h" #include "llvm/ADT/Statistic.h" -#include "llvm/Analysis/Dominators.h" #include "llvm/Analysis/ValueTracking.h" +#include "llvm/CodeGen/Analysis.h" +#include "llvm/CodeGen/Passes.h" #include "llvm/IR/Attributes.h" #include "llvm/IR/Constants.h" #include "llvm/IR/DataLayout.h" @@ -35,43 +33,69 @@ #include "llvm/IR/Intrinsics.h" #include "llvm/IR/Module.h" #include "llvm/Support/CommandLine.h" +#include "llvm/Target/TargetSubtargetInfo.h" #include using namespace llvm; +#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 -EnableSelectionDAGSP("enable-selectiondag-sp", cl::init(true), - cl::Hidden); +static cl::opt EnableSelectionDAGSP("enable-selectiondag-sp", + cl::init(true), cl::Hidden); char StackProtector::ID = 0; -INITIALIZE_PASS(StackProtector, "stack-protector", - "Insert stack protectors", false, true) +INITIALIZE_PASS(StackProtector, "stack-protector", "Insert stack protectors", + false, true) FunctionPass *llvm::createStackProtectorPass(const TargetMachine *TM) { return new StackProtector(TM); } -StackProtector::SSPLayoutKind StackProtector::getSSPLayout(const AllocaInst *AI) - const { +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(); - DT = getAnalysisIfAvailable(); - TLI = TM->getTargetLowering(); - - if (!RequiresStackProtector()) return false; - - Attribute Attr = - Fn.getAttributes().getAttribute(AttributeSet::FunctionIndex, - "stack-protector-buffer-size"); - if (Attr.isStringAttribute()) - Attr.getValueAsString().getAsInteger(10, SSPBufferSize); + DominatorTreeWrapperPass *DTWP = + getAnalysisIfAvailable(); + DT = DTWP ? &DTWP->getDomTree() : nullptr; + TLI = TM->getSubtargetImpl()->getTargetLowering(); + + Attribute Attr = Fn.getAttributes().getAttribute( + AttributeSet::FunctionIndex, "stack-protector-buffer-size"); + if (Attr.isStringAttribute() && + Attr.getValueAsString().getAsInteger(10, SSPBufferSize)) + return false; // Invalid integer string + + if (!RequiresStackProtector()) + return false; ++NumFunProtected; return InsertStackProtectors(); @@ -81,9 +105,10 @@ bool StackProtector::runOnFunction(Function &Fn) { /// 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; + bool Strong, + bool InStruct) const { + if (!Ty) + return false; if (ArrayType *AT = dyn_cast(Ty)) { if (!AT->getElementType()->isIntegerTy(8)) { // If we're on a non-Darwin platform or we're inside of a structure, don't @@ -99,7 +124,7 @@ bool StackProtector::ContainsProtectableArray(Type *Ty, bool &IsLarge, if (SSPBufferSize <= TLI->getDataLayout()->getTypeAllocSize(AT)) { IsLarge = true; return true; - } + } if (Strong) // Require a protector for all arrays in strong mode @@ -107,11 +132,13 @@ bool StackProtector::ContainsProtectableArray(Type *Ty, bool &IsLarge, } const StructType *ST = dyn_cast(Ty); - if (!ST) return false; + if (!ST) + return false; bool NeedsProtector = false; for (StructType::element_iterator I = ST->element_begin(), - E = ST->element_end(); I != E; ++I) + 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 @@ -125,9 +152,7 @@ bool StackProtector::ContainsProtectableArray(Type *Ty, bool &IsLarge, } bool StackProtector::HasAddressTaken(const Instruction *AI) { - for (Value::const_use_iterator UI = AI->use_begin(), UE = AI->use_end(); - UI != UE; ++UI) { - const User *U = *UI; + for (const User *U : AI->users()) { if (const StoreInst *SI = dyn_cast(U)) { if (AI == SI->getValueOperand()) return true; @@ -188,8 +213,8 @@ bool StackProtector::RequiresStackProtector() { 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) { + for (BasicBlock::iterator II = BB->begin(), IE = BB->end(); II != IE; + ++II) { if (AllocaInst *AI = dyn_cast(II)) { if (AI->isArrayAllocation()) { // SSP-Strong: Enable protectors for any call to alloca, regardless @@ -198,7 +223,7 @@ bool StackProtector::RequiresStackProtector() { return true; if (const ConstantInt *CI = - dyn_cast(AI->getArraySize())) { + dyn_cast(AI->getArraySize())) { if (CI->getLimitedValue(SSPBufferSize) >= SSPBufferSize) { // A call to alloca with size >= SSPBufferSize requires // stack protectors. @@ -239,7 +264,7 @@ bool StackProtector::RequiresStackProtector() { static bool InstructionWillNotHaveChain(const Instruction *I) { return !I->mayHaveSideEffects() && !I->mayReadFromMemory() && - isSafeToSpeculativelyExecute(I); + isSafeToSpeculativelyExecute(I); } /// Identify if RI has a previous instruction in the "Tail Position" and return @@ -259,7 +284,7 @@ static CallInst *FindPotentialTailCall(BasicBlock *BB, ReturnInst *RI, const unsigned MaxSearch = 4; bool NoInterposingChain = true; - for (BasicBlock::reverse_iterator I = llvm::next(BB->rbegin()), E = BB->rend(); + for (BasicBlock::reverse_iterator I = std::next(BB->rbegin()), E = BB->rend(); I != E && SearchCounter < MaxSearch; ++I) { Instruction *Inst = &*I; @@ -289,13 +314,14 @@ static CallInst *FindPotentialTailCall(BasicBlock *BB, ReturnInst *RI, // If we did not find a call see if we have an instruction that may create // an interposing chain. - NoInterposingChain = NoInterposingChain && InstructionWillNotHaveChain(Inst); + NoInterposingChain = + NoInterposingChain && InstructionWillNotHaveChain(Inst); // Increment max search. SearchCounter++; } - return 0; + return nullptr; } /// Insert code into the entry block that stores the __stack_chk_guard @@ -316,22 +342,21 @@ static bool CreatePrologue(Function *F, Module *M, ReturnInst *RI, unsigned AddressSpace, Offset; if (TLI->getStackCookieLocation(AddressSpace, Offset)) { Constant *OffsetVal = - ConstantInt::get(Type::getInt32Ty(RI->getContext()), Offset); + ConstantInt::get(Type::getInt32Ty(RI->getContext()), Offset); - StackGuardVar = ConstantExpr::getIntToPtr(OffsetVal, - PointerType::get(PtrTy, - AddressSpace)); + StackGuardVar = ConstantExpr::getIntToPtr( + OffsetVal, PointerType::get(PtrTy, AddressSpace)); } else if (Trip.getOS() == llvm::Triple::OpenBSD) { StackGuardVar = M->getOrInsertGlobal("__guard_local", PtrTy); cast(StackGuardVar) - ->setVisibility(GlobalValue::HiddenVisibility); + ->setVisibility(GlobalValue::HiddenVisibility); } else { SupportsSelectionDAGSP = true; StackGuardVar = M->getOrInsertGlobal("__stack_chk_guard", PtrTy); } IRBuilder<> B(&F->getEntryBlock().front()); - AI = B.CreateAlloca(PtrTy, 0, "StackGuardSlot"); + AI = B.CreateAlloca(PtrTy, nullptr, "StackGuardSlot"); LoadInst *LI = B.CreateLoad(StackGuardVar, "StackGuard"); B.CreateCall2(Intrinsic::getDeclaration(M, Intrinsic::stackprotector), LI, AI); @@ -348,11 +373,11 @@ static bool CreatePrologue(Function *F, Module *M, ReturnInst *RI, bool StackProtector::InsertStackProtectors() { bool HasPrologue = false; bool SupportsSelectionDAGSP = - EnableSelectionDAGSP && !TM->Options.EnableFastISel; - AllocaInst *AI = 0; // Place on stack that stores the stack guard. - Value *StackGuardVar = 0; // The stack guard variable. + 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; ) { + for (Function::iterator I = F->begin(), E = F->end(); I != E;) { BasicBlock *BB = I++; ReturnInst *RI = dyn_cast(BB->getTerminator()); if (!RI) @@ -360,26 +385,26 @@ bool StackProtector::InsertStackProtectors() { if (!HasPrologue) { HasPrologue = true; - SupportsSelectionDAGSP &= CreatePrologue(F, M, RI, TLI, Trip, AI, - StackGuardVar); + 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 = 0; + 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 != 0 && "BB must have a terminator instruction at " - "this point."); + assert(InsertionPt != nullptr && "BB must have a terminator instruction at " + "this point."); } Function *Intrinsic = - Intrinsic::getDeclaration(M, Intrinsic::stackprotectorcheck); + Intrinsic::getDeclaration(M, Intrinsic::stackprotectorcheck); CallInst::Create(Intrinsic, StackGuardVar, "", InsertionPt); } else {