-//===----------------------------------------------------------------------===//
-// Fortified Library Call Optimizations
-//===----------------------------------------------------------------------===//
-
-static bool isFortifiedCallFoldable(CallInst *CI, unsigned SizeCIOp, unsigned SizeArgOp,
- bool isString) {
- if (CI->getArgOperand(SizeCIOp) == CI->getArgOperand(SizeArgOp))
- return true;
- if (ConstantInt *SizeCI =
- dyn_cast<ConstantInt>(CI->getArgOperand(SizeCIOp))) {
- if (SizeCI->isAllOnesValue())
- return true;
- if (isString) {
- uint64_t Len = GetStringLength(CI->getArgOperand(SizeArgOp));
- // If the length is 0 we don't know how long it is and so we can't
- // remove the check.
- if (Len == 0)
- return false;
- return SizeCI->getZExtValue() >= Len;
- }
- if (ConstantInt *Arg = dyn_cast<ConstantInt>(CI->getArgOperand(SizeArgOp)))
- return SizeCI->getZExtValue() >= Arg->getZExtValue();
- }
- return false;
-}
-
-Value *LibCallSimplifier::optimizeMemCpyChk(CallInst *CI, IRBuilder<> &B) {
- Function *Callee = CI->getCalledFunction();
- FunctionType *FT = Callee->getFunctionType();
- LLVMContext &Context = CI->getContext();
-
- // Check if this has the right signature.
- if (FT->getNumParams() != 4 || FT->getReturnType() != FT->getParamType(0) ||
- !FT->getParamType(0)->isPointerTy() ||
- !FT->getParamType(1)->isPointerTy() ||
- FT->getParamType(2) != DL->getIntPtrType(Context) ||
- FT->getParamType(3) != DL->getIntPtrType(Context))
- return nullptr;
-
- if (isFortifiedCallFoldable(CI, 3, 2, false)) {
- B.CreateMemCpy(CI->getArgOperand(0), CI->getArgOperand(1),
- CI->getArgOperand(2), 1);
- return CI->getArgOperand(0);
- }
- return nullptr;
-}
-
-Value *LibCallSimplifier::optimizeMemMoveChk(CallInst *CI, IRBuilder<> &B) {
- Function *Callee = CI->getCalledFunction();
- FunctionType *FT = Callee->getFunctionType();
- LLVMContext &Context = CI->getContext();
-
- // Check if this has the right signature.
- if (FT->getNumParams() != 4 || FT->getReturnType() != FT->getParamType(0) ||
- !FT->getParamType(0)->isPointerTy() ||
- !FT->getParamType(1)->isPointerTy() ||
- FT->getParamType(2) != DL->getIntPtrType(Context) ||
- FT->getParamType(3) != DL->getIntPtrType(Context))
- return nullptr;
-
- if (isFortifiedCallFoldable(CI, 3, 2, false)) {
- B.CreateMemMove(CI->getArgOperand(0), CI->getArgOperand(1),
- CI->getArgOperand(2), 1);
- return CI->getArgOperand(0);
- }
- return nullptr;
-}
-
-Value *LibCallSimplifier::optimizeMemSetChk(CallInst *CI, IRBuilder<> &B) {
- Function *Callee = CI->getCalledFunction();
- FunctionType *FT = Callee->getFunctionType();
- LLVMContext &Context = CI->getContext();
-
- // Check if this has the right signature.
- if (FT->getNumParams() != 4 || FT->getReturnType() != FT->getParamType(0) ||
- !FT->getParamType(0)->isPointerTy() ||
- !FT->getParamType(1)->isIntegerTy() ||
- FT->getParamType(2) != DL->getIntPtrType(Context) ||
- FT->getParamType(3) != DL->getIntPtrType(Context))
- return nullptr;
-
- if (isFortifiedCallFoldable(CI, 3, 2, false)) {
- Value *Val = B.CreateIntCast(CI->getArgOperand(1), B.getInt8Ty(), false);
- B.CreateMemSet(CI->getArgOperand(0), Val, CI->getArgOperand(2), 1);
- return CI->getArgOperand(0);
- }
- return nullptr;
-}
-
-Value *LibCallSimplifier::optimizeStrCpyChk(CallInst *CI, IRBuilder<> &B) {
- Function *Callee = CI->getCalledFunction();
- StringRef Name = Callee->getName();
- FunctionType *FT = Callee->getFunctionType();
- LLVMContext &Context = CI->getContext();
-
- // Check if this has the right signature.
- if (FT->getNumParams() != 3 || FT->getReturnType() != FT->getParamType(0) ||
- FT->getParamType(0) != FT->getParamType(1) ||
- FT->getParamType(0) != Type::getInt8PtrTy(Context) ||
- FT->getParamType(2) != DL->getIntPtrType(Context))
- return nullptr;
-
- Value *Dst = CI->getArgOperand(0), *Src = CI->getArgOperand(1);
- if (Dst == Src) // __strcpy_chk(x,x) -> x
- return Src;
-
- // If a) we don't have any length information, or b) we know this will
- // fit then just lower to a plain strcpy. Otherwise we'll keep our
- // strcpy_chk call which may fail at runtime if the size is too long.
- // TODO: It might be nice to get a maximum length out of the possible
- // string lengths for varying.
- if (isFortifiedCallFoldable(CI, 2, 1, true)) {
- Value *Ret = EmitStrCpy(Dst, Src, B, DL, TLI, Name.substr(2, 6));
- return Ret;
- } else {
- // Maybe we can stil fold __strcpy_chk to __memcpy_chk.
- uint64_t Len = GetStringLength(Src);
- if (Len == 0)
- return nullptr;
-
- // This optimization require DataLayout.
- if (!DL)
- return nullptr;
-
- Value *Ret = EmitMemCpyChk(
- Dst, Src, ConstantInt::get(DL->getIntPtrType(Context), Len),
- CI->getArgOperand(2), B, DL, TLI);
- return Ret;
- }
- return nullptr;
-}
-
-Value *LibCallSimplifier::optimizeStpCpyChk(CallInst *CI, IRBuilder<> &B) {
- Function *Callee = CI->getCalledFunction();
- StringRef Name = Callee->getName();
- FunctionType *FT = Callee->getFunctionType();
- LLVMContext &Context = CI->getContext();
-
- // Check if this has the right signature.
- if (FT->getNumParams() != 3 || FT->getReturnType() != FT->getParamType(0) ||
- FT->getParamType(0) != FT->getParamType(1) ||
- FT->getParamType(0) != Type::getInt8PtrTy(Context) ||
- FT->getParamType(2) != DL->getIntPtrType(FT->getParamType(0)))
- return nullptr;
-
- Value *Dst = CI->getArgOperand(0), *Src = CI->getArgOperand(1);
- if (Dst == Src) { // stpcpy(x,x) -> x+strlen(x)
- Value *StrLen = EmitStrLen(Src, B, DL, TLI);
- return StrLen ? B.CreateInBoundsGEP(Dst, StrLen) : nullptr;
- }
-
- // If a) we don't have any length information, or b) we know this will
- // fit then just lower to a plain stpcpy. Otherwise we'll keep our
- // stpcpy_chk call which may fail at runtime if the size is too long.
- // TODO: It might be nice to get a maximum length out of the possible
- // string lengths for varying.
- if (isFortifiedCallFoldable(CI, 2, 1, true)) {
- Value *Ret = EmitStrCpy(Dst, Src, B, DL, TLI, Name.substr(2, 6));
- return Ret;
- } else {
- // Maybe we can stil fold __stpcpy_chk to __memcpy_chk.
- uint64_t Len = GetStringLength(Src);
- if (Len == 0)
- return nullptr;
-
- // This optimization require DataLayout.
- if (!DL)
- return nullptr;
-
- Type *PT = FT->getParamType(0);
- Value *LenV = ConstantInt::get(DL->getIntPtrType(PT), Len);
- Value *DstEnd =
- B.CreateGEP(Dst, ConstantInt::get(DL->getIntPtrType(PT), Len - 1));
- if (!EmitMemCpyChk(Dst, Src, LenV, CI->getArgOperand(2), B, DL, TLI))
- return nullptr;
- return DstEnd;
- }
- return nullptr;
-}
-
-Value *LibCallSimplifier::optimizeStrNCpyChk(CallInst *CI, IRBuilder<> &B) {
- Function *Callee = CI->getCalledFunction();
- StringRef Name = Callee->getName();
- FunctionType *FT = Callee->getFunctionType();
- LLVMContext &Context = CI->getContext();
-
- // Check if this has the right signature.
- if (FT->getNumParams() != 4 || FT->getReturnType() != FT->getParamType(0) ||
- FT->getParamType(0) != FT->getParamType(1) ||
- FT->getParamType(0) != Type::getInt8PtrTy(Context) ||
- !FT->getParamType(2)->isIntegerTy() ||
- FT->getParamType(3) != DL->getIntPtrType(Context))
- return nullptr;
-
- if (isFortifiedCallFoldable(CI, 3, 2, false)) {
- Value *Ret =
- EmitStrNCpy(CI->getArgOperand(0), CI->getArgOperand(1),
- CI->getArgOperand(2), B, DL, TLI, Name.substr(2, 7));
- return Ret;
- }
- return nullptr;
-}
-