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[SimplifyLibCalls] Factor out signature checks for fortifiable libcalls. 

The checks are the same for fortified counterparts to the libcalls, so
we might as well do them in a single place.

Differential Revision: http://reviews.llvm.org/D6539

llvm-svn: 225638
This commit is contained in:
Ahmed Bougacha 2015-01-12 17:18:19 +00:00
parent 3f2e761826
commit b7d8afb6c5
1 changed files with 73 additions and 27 deletions
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100
llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
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@ -116,6 +116,70 @@ static bool hasUnaryFloatFn(const TargetLibraryInfo *TLI, Type *Ty,
}
}
/// \brief Returns whether \p F matches the signature expected for the
/// string/memory copying library function \p Func.
/// Acceptable functions are st[rp][n]?cpy, memove, memcpy, and memset.
/// Their fortified (_chk) counterparts are also accepted.
static bool checkStringCopyLibFuncSignature(Function *F, LibFunc::Func Func,
const DataLayout *DL) {
FunctionType *FT = F->getFunctionType();
LLVMContext &Context = F->getContext();
Type *PCharTy = Type::getInt8PtrTy(Context);
Type *SizeTTy = DL ? DL->getIntPtrType(Context) : nullptr;
unsigned NumParams = FT->getNumParams();
// All string libfuncs return the same type as the first parameter.
if (FT->getReturnType() != FT->getParamType(0))
return false;
switch (Func) {
default:
llvm_unreachable("Can't check signature for non-string-copy libfunc.");
case LibFunc::stpncpy_chk:
case LibFunc::strncpy_chk:
--NumParams; // fallthrough
case LibFunc::stpncpy:
case LibFunc::strncpy: {
if (NumParams != 3 || FT->getParamType(0) != FT->getParamType(1) ||
FT->getParamType(0) != PCharTy || !FT->getParamType(2)->isIntegerTy())
return false;
break;
}
case LibFunc::strcpy_chk:
case LibFunc::stpcpy_chk:
--NumParams; // fallthrough
case LibFunc::stpcpy:
case LibFunc::strcpy: {
if (NumParams != 2 || FT->getParamType(0) != FT->getParamType(1) ||
FT->getParamType(0) != PCharTy)
return false;
break;
}
case LibFunc::memmove_chk:
case LibFunc::memcpy_chk:
--NumParams; // fallthrough
case LibFunc::memmove:
case LibFunc::memcpy: {
if (NumParams != 3 || !FT->getParamType(0)->isPointerTy() ||
!FT->getParamType(1)->isPointerTy() || FT->getParamType(2) != SizeTTy)
return false;
break;
}
case LibFunc::memset_chk:
--NumParams; // fallthrough
case LibFunc::memset: {
if (NumParams != 3 || !FT->getParamType(0)->isPointerTy() ||
!FT->getParamType(1)->isIntegerTy() || FT->getParamType(2) != SizeTTy)
return false;
break;
}
}
// If this is a fortified libcall, the last parameter is a size_t.
if (NumParams == FT->getNumParams() - 1)
return FT->getParamType(FT->getNumParams() - 1) == SizeTTy;
return true;
}
//===----------------------------------------------------------------------===//
// Fortified Library Call Optimizations
//===----------------------------------------------------------------------===//
@ -600,11 +664,8 @@ Value *LibCallSimplifier::optimizeStrNCmp(CallInst *CI, IRBuilder<> &B) {
Value *LibCallSimplifier::optimizeStrCpy(CallInst *CI, IRBuilder<> &B) {
Function *Callee = CI->getCalledFunction();
// Verify the "strcpy" function prototype.
FunctionType *FT = Callee->getFunctionType();
if (FT->getNumParams() != 2 || FT->getReturnType() != FT->getParamType(0) ||
FT->getParamType(0) != FT->getParamType(1) ||
FT->getParamType(0) != B.getInt8PtrTy())
if (!checkStringCopyLibFuncSignature(Callee, LibFunc::strcpy, DL))
return nullptr;
Value *Dst = CI->getArgOperand(0), *Src = CI->getArgOperand(1);
@ -631,9 +692,8 @@ Value *LibCallSimplifier::optimizeStpCpy(CallInst *CI, IRBuilder<> &B) {
Function *Callee = CI->getCalledFunction();
// Verify the "stpcpy" function prototype.
FunctionType *FT = Callee->getFunctionType();
if (FT->getNumParams() != 2 || FT->getReturnType() != FT->getParamType(0) ||
FT->getParamType(0) != FT->getParamType(1) ||
FT->getParamType(0) != B.getInt8PtrTy())
if (!checkStringCopyLibFuncSignature(Callee, LibFunc::stpcpy, DL))
return nullptr;
// These optimizations require DataLayout.
@ -665,10 +725,8 @@ Value *LibCallSimplifier::optimizeStpCpy(CallInst *CI, IRBuilder<> &B) {
Value *LibCallSimplifier::optimizeStrNCpy(CallInst *CI, IRBuilder<> &B) {
Function *Callee = CI->getCalledFunction();
FunctionType *FT = Callee->getFunctionType();
if (FT->getNumParams() != 3 || FT->getReturnType() != FT->getParamType(0) ||
FT->getParamType(0) != FT->getParamType(1) ||
FT->getParamType(0) != B.getInt8PtrTy() ||
!FT->getParamType(2)->isIntegerTy())
if (!checkStringCopyLibFuncSignature(Callee, LibFunc::strncpy, DL))
return nullptr;
Value *Dst = CI->getArgOperand(0);
@ -976,11 +1034,7 @@ Value *LibCallSimplifier::optimizeMemCpy(CallInst *CI, IRBuilder<> &B) {
if (!DL)
return nullptr;
FunctionType *FT = Callee->getFunctionType();
if (FT->getNumParams() != 3 || FT->getReturnType() != FT->getParamType(0) ||
!FT->getParamType(0)->isPointerTy() ||
!FT->getParamType(1)->isPointerTy() ||
FT->getParamType(2) != DL->getIntPtrType(CI->getContext()))
if (!checkStringCopyLibFuncSignature(Callee, LibFunc::memcpy, DL))
return nullptr;
// memcpy(x, y, n) -> llvm.memcpy(x, y, n, 1)
@ -995,11 +1049,7 @@ Value *LibCallSimplifier::optimizeMemMove(CallInst *CI, IRBuilder<> &B) {
if (!DL)
return nullptr;
FunctionType *FT = Callee->getFunctionType();
if (FT->getNumParams() != 3 || FT->getReturnType() != FT->getParamType(0) ||
!FT->getParamType(0)->isPointerTy() ||
!FT->getParamType(1)->isPointerTy() ||
FT->getParamType(2) != DL->getIntPtrType(CI->getContext()))
if (!checkStringCopyLibFuncSignature(Callee, LibFunc::memmove, DL))
return nullptr;
// memmove(x, y, n) -> llvm.memmove(x, y, n, 1)
@ -1014,11 +1064,7 @@ Value *LibCallSimplifier::optimizeMemSet(CallInst *CI, IRBuilder<> &B) {
if (!DL)
return nullptr;
FunctionType *FT = Callee->getFunctionType();
if (FT->getNumParams() != 3 || FT->getReturnType() != FT->getParamType(0) ||
!FT->getParamType(0)->isPointerTy() ||
!FT->getParamType(1)->isIntegerTy() ||
FT->getParamType(2) != DL->getIntPtrType(FT->getParamType(0)))
if (!checkStringCopyLibFuncSignature(Callee, LibFunc::memset, DL))
return nullptr;
// memset(p, v, n) -> llvm.memset(p, v, n, 1)