diff options
Diffstat (limited to 'lib/CodeGen/StackProtector.cpp')
| -rw-r--r-- | lib/CodeGen/StackProtector.cpp | 58 |
1 files changed, 47 insertions, 11 deletions
diff --git a/lib/CodeGen/StackProtector.cpp b/lib/CodeGen/StackProtector.cpp index c2c010a29d44..a8aafe78748d 100644 --- a/lib/CodeGen/StackProtector.cpp +++ b/lib/CodeGen/StackProtector.cpp @@ -1,4 +1,4 @@ -//===-- StackProtector.cpp - Stack Protector Insertion --------------------===// +//===- StackProtector.cpp - Stack Protector Insertion ---------------------===// // // The LLVM Compiler Infrastructure // @@ -14,30 +14,38 @@ // //===----------------------------------------------------------------------===// -#include "llvm/CodeGen/StackProtector.h" #include "llvm/ADT/SmallPtrSet.h" #include "llvm/ADT/Statistic.h" #include "llvm/Analysis/BranchProbabilityInfo.h" #include "llvm/Analysis/EHPersonalities.h" -#include "llvm/Analysis/ValueTracking.h" +#include "llvm/Analysis/OptimizationDiagnosticInfo.h" #include "llvm/CodeGen/Passes.h" +#include "llvm/CodeGen/StackProtector.h" #include "llvm/IR/Attributes.h" +#include "llvm/IR/BasicBlock.h" #include "llvm/IR/Constants.h" #include "llvm/IR/DataLayout.h" #include "llvm/IR/DebugInfo.h" +#include "llvm/IR/DebugLoc.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/Instruction.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/IR/Type.h" +#include "llvm/IR/User.h" +#include "llvm/Pass.h" +#include "llvm/Support/Casting.h" #include "llvm/Support/CommandLine.h" +#include "llvm/Target/TargetLowering.h" +#include "llvm/Target/TargetMachine.h" +#include "llvm/Target/TargetOptions.h" #include "llvm/Target/TargetSubtargetInfo.h" -#include <cstdlib> +#include <utility> + using namespace llvm; #define DEBUG_TYPE "stack-protector" @@ -51,7 +59,7 @@ static cl::opt<bool> EnableSelectionDAGSP("enable-selectiondag-sp", char StackProtector::ID = 0; INITIALIZE_TM_PASS(StackProtector, "stack-protector", "Insert stack protectors", - false, true) + false, true) FunctionPass *llvm::createStackProtectorPass(const TargetMachine *TM) { return new StackProtector(TM); @@ -222,7 +230,16 @@ bool StackProtector::RequiresStackProtector() { if (F->hasFnAttribute(Attribute::SafeStack)) return false; + // We are constructing the OptimizationRemarkEmitter on the fly rather than + // using the analysis pass to avoid building DominatorTree and LoopInfo which + // are not available this late in the IR pipeline. + OptimizationRemarkEmitter ORE(F); + if (F->hasFnAttribute(Attribute::StackProtectReq)) { + ORE.emit(OptimizationRemark(DEBUG_TYPE, "StackProtectorRequested", F) + << "Stack protection applied to function " + << ore::NV("Function", F) + << " due to a function attribute or command-line switch"); NeedsProtector = true; Strong = true; // Use the same heuristic as strong to determine SSPLayout } else if (F->hasFnAttribute(Attribute::StackProtectStrong)) @@ -236,20 +253,29 @@ bool StackProtector::RequiresStackProtector() { for (const Instruction &I : BB) { if (const AllocaInst *AI = dyn_cast<AllocaInst>(&I)) { if (AI->isArrayAllocation()) { + OptimizationRemark Remark(DEBUG_TYPE, "StackProtectorAllocaOrArray", + &I); + Remark + << "Stack protection applied to function " + << ore::NV("Function", F) + << " due to a call to alloca or use of a variable length array"; 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)); + ORE.emit(Remark); NeedsProtector = true; } else if (Strong) { // Require protectors for all alloca calls in strong mode. Layout.insert(std::make_pair(AI, SSPLK_SmallArray)); + ORE.emit(Remark); NeedsProtector = true; } } else { // A call to alloca with a variable size requires protectors. Layout.insert(std::make_pair(AI, SSPLK_LargeArray)); + ORE.emit(Remark); NeedsProtector = true; } continue; @@ -259,6 +285,11 @@ bool StackProtector::RequiresStackProtector() { if (ContainsProtectableArray(AI->getAllocatedType(), IsLarge, Strong)) { Layout.insert(std::make_pair(AI, IsLarge ? SSPLK_LargeArray : SSPLK_SmallArray)); + ORE.emit(OptimizationRemark(DEBUG_TYPE, "StackProtectorBuffer", &I) + << "Stack protection applied to function " + << ore::NV("Function", F) + << " due to a stack allocated buffer or struct containing a " + "buffer"); NeedsProtector = true; continue; } @@ -266,6 +297,11 @@ bool StackProtector::RequiresStackProtector() { if (Strong && HasAddressTaken(AI)) { ++NumAddrTaken; Layout.insert(std::make_pair(AI, SSPLK_AddrOf)); + ORE.emit( + OptimizationRemark(DEBUG_TYPE, "StackProtectorAddressTaken", &I) + << "Stack protection applied to function " + << ore::NV("Function", F) + << " due to the address of a local variable being taken"); NeedsProtector = true; } } @@ -448,13 +484,13 @@ BasicBlock *StackProtector::CreateFailBB() { Constant *StackChkFail = M->getOrInsertFunction("__stack_smash_handler", Type::getVoidTy(Context), - Type::getInt8PtrTy(Context), nullptr); + Type::getInt8PtrTy(Context)); B.CreateCall(StackChkFail, B.CreateGlobalStringPtr(F->getName(), "SSH")); } else { Constant *StackChkFail = - M->getOrInsertFunction("__stack_chk_fail", Type::getVoidTy(Context), - nullptr); + M->getOrInsertFunction("__stack_chk_fail", Type::getVoidTy(Context)); + B.CreateCall(StackChkFail, {}); } B.CreateUnreachable(); |