diff options
Diffstat (limited to 'contrib/llvm/lib/CodeGen/StackProtector.cpp')
-rw-r--r-- | contrib/llvm/lib/CodeGen/StackProtector.cpp | 63 |
1 files changed, 42 insertions, 21 deletions
diff --git a/contrib/llvm/lib/CodeGen/StackProtector.cpp b/contrib/llvm/lib/CodeGen/StackProtector.cpp index 9020449..accfe7b 100644 --- a/contrib/llvm/lib/CodeGen/StackProtector.cpp +++ b/contrib/llvm/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" @@ -38,6 +36,8 @@ #include <cstdlib> 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."); @@ -58,19 +58,43 @@ 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<DominatorTree>(); + DominatorTreeWrapperPass *DTWP = + getAnalysisIfAvailable<DominatorTreeWrapperPass>(); + DT = DTWP ? &DTWP->getDomTree() : nullptr; 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); + if (Attr.isStringAttribute() && + Attr.getValueAsString().getAsInteger(10, SSPBufferSize)) + return false; // Invalid integer string + + if (!RequiresStackProtector()) + return false; ++NumFunProtected; return InsertStackProtectors(); @@ -127,9 +151,7 @@ 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<StoreInst>(U)) { if (AI == SI->getValueOperand()) return true; @@ -261,8 +283,7 @@ 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; @@ -299,7 +320,7 @@ static CallInst *FindPotentialTailCall(BasicBlock *BB, ReturnInst *RI, SearchCounter++; } - return 0; + return nullptr; } /// Insert code into the entry block that stores the __stack_chk_guard @@ -334,7 +355,7 @@ static bool CreatePrologue(Function *F, Module *M, ReturnInst *RI, } 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); @@ -352,8 +373,8 @@ 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. + 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++; @@ -370,14 +391,14 @@ bool StackProtector::InsertStackProtectors() { 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 " + assert(InsertionPt != nullptr && "BB must have a terminator instruction at " "this point."); } |