#include "llvm/IR/PatternMatch.h"
#include "llvm/Support/Allocator.h"
#include "llvm/Support/CommandLine.h"
-#include "llvm/Target/TargetLibraryInfo.h"
+#include "llvm/Analysis/TargetLibraryInfo.h"
#include "llvm/Transforms/Utils/BuildLibCalls.h"
+#include "llvm/Transforms/Utils/Local.h"
using namespace llvm;
using namespace PatternMatch;
}
/// \brief Check whether the overloaded unary floating point function
-/// corresponing to \a Ty is available.
+/// corresponding to \a Ty is available.
static bool hasUnaryFloatFn(const TargetLibraryInfo *TLI, Type *Ty,
LibFunc::Func DoubleFn, LibFunc::Func FloatFn,
LibFunc::Func LongDoubleFn) {
/// 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) {
+static bool checkStringCopyLibFuncSignature(Function *F, LibFunc::Func Func) {
+ const DataLayout &DL = F->getParent()->getDataLayout();
FunctionType *FT = F->getFunctionType();
LLVMContext &Context = F->getContext();
Type *PCharTy = Type::getInt8PtrTy(Context);
- Type *SizeTTy = DL ? DL->getIntPtrType(Context) : nullptr;
+ Type *SizeTTy = DL.getIntPtrType(Context);
unsigned NumParams = FT->getNumParams();
// All string libfuncs return the same type as the first parameter.
return true;
}
-//===----------------------------------------------------------------------===//
-// 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;
-}
-
//===----------------------------------------------------------------------===//
// String and Memory Library Call Optimizations
//===----------------------------------------------------------------------===//
if (Len == 0)
return Dst;
- // These optimizations require DataLayout.
- if (!DL)
- return nullptr;
-
return emitStrLenMemCpy(Src, Dst, Len, B);
}
// Now that we have the destination's length, we must index into the
// destination's pointer to get the actual memcpy destination (end of
// the string .. we're concatenating).
- Value *CpyDst = B.CreateGEP(Dst, DstLen, "endptr");
+ Value *CpyDst = B.CreateGEP(B.getInt8Ty(), Dst, DstLen, "endptr");
// We have enough information to now generate the memcpy call to do the
// concatenation for us. Make a memcpy to copy the nul byte with align = 1.
- B.CreateMemCpy(
- CpyDst, Src,
- ConstantInt::get(DL->getIntPtrType(Src->getContext()), Len + 1), 1);
+ B.CreateMemCpy(CpyDst, Src,
+ ConstantInt::get(DL.getIntPtrType(Src->getContext()), Len + 1),
+ 1);
return Dst;
}
if (SrcLen == 0 || Len == 0)
return Dst;
- // These optimizations require DataLayout.
- if (!DL)
- return nullptr;
-
// We don't optimize this case
if (Len < SrcLen)
return nullptr;
// of the input string and turn this into memchr.
ConstantInt *CharC = dyn_cast<ConstantInt>(CI->getArgOperand(1));
if (!CharC) {
- // These optimizations require DataLayout.
- if (!DL)
- return nullptr;
-
uint64_t Len = GetStringLength(SrcStr);
if (Len == 0 || !FT->getParamType(1)->isIntegerTy(32)) // memchr needs i32.
return nullptr;
- return EmitMemChr(
- SrcStr, CI->getArgOperand(1), // include nul.
- ConstantInt::get(DL->getIntPtrType(CI->getContext()), Len), B, DL, TLI);
+ return EmitMemChr(SrcStr, CI->getArgOperand(1), // include nul.
+ ConstantInt::get(DL.getIntPtrType(CI->getContext()), Len),
+ B, DL, TLI);
}
// Otherwise, the character is a constant, see if the first argument is
// a string literal. If so, we can constant fold.
StringRef Str;
if (!getConstantStringInfo(SrcStr, Str)) {
- if (DL && CharC->isZero()) // strchr(p, 0) -> p + strlen(p)
- return B.CreateGEP(SrcStr, EmitStrLen(SrcStr, B, DL, TLI), "strchr");
+ if (CharC->isZero()) // strchr(p, 0) -> p + strlen(p)
+ return B.CreateGEP(B.getInt8Ty(), SrcStr, EmitStrLen(SrcStr, B, DL, TLI), "strchr");
return nullptr;
}
return Constant::getNullValue(CI->getType());
// strchr(s+n,c) -> gep(s+n+i,c)
- return B.CreateGEP(SrcStr, B.getInt64(I), "strchr");
+ return B.CreateGEP(B.getInt8Ty(), SrcStr, B.getInt64(I), "strchr");
}
Value *LibCallSimplifier::optimizeStrRChr(CallInst *CI, IRBuilder<> &B) {
StringRef Str;
if (!getConstantStringInfo(SrcStr, Str)) {
// strrchr(s, 0) -> strchr(s, 0)
- if (DL && CharC->isZero())
- return EmitStrChr(SrcStr, '\0', B, DL, TLI);
+ if (CharC->isZero())
+ return EmitStrChr(SrcStr, '\0', B, TLI);
return nullptr;
}
return Constant::getNullValue(CI->getType());
// strrchr(s+n,c) -> gep(s+n+i,c)
- return B.CreateGEP(SrcStr, B.getInt64(I), "strrchr");
+ return B.CreateGEP(B.getInt8Ty(), SrcStr, B.getInt64(I), "strrchr");
}
Value *LibCallSimplifier::optimizeStrCmp(CallInst *CI, IRBuilder<> &B) {
uint64_t Len1 = GetStringLength(Str1P);
uint64_t Len2 = GetStringLength(Str2P);
if (Len1 && Len2) {
- // These optimizations require DataLayout.
- if (!DL)
- return nullptr;
-
return EmitMemCmp(Str1P, Str2P,
- ConstantInt::get(DL->getIntPtrType(CI->getContext()),
+ ConstantInt::get(DL.getIntPtrType(CI->getContext()),
std::min(Len1, Len2)),
B, DL, TLI);
}
if (Length == 0) // strncmp(x,y,0) -> 0
return ConstantInt::get(CI->getType(), 0);
- if (DL && Length == 1) // strncmp(x,y,1) -> memcmp(x,y,1)
+ if (Length == 1) // strncmp(x,y,1) -> memcmp(x,y,1)
return EmitMemCmp(Str1P, Str2P, CI->getArgOperand(2), B, DL, TLI);
StringRef Str1, Str2;
Value *LibCallSimplifier::optimizeStrCpy(CallInst *CI, IRBuilder<> &B) {
Function *Callee = CI->getCalledFunction();
- if (!checkStringCopyLibFuncSignature(Callee, LibFunc::strcpy, DL))
+ if (!checkStringCopyLibFuncSignature(Callee, LibFunc::strcpy))
return nullptr;
Value *Dst = CI->getArgOperand(0), *Src = CI->getArgOperand(1);
if (Dst == Src) // strcpy(x,x) -> x
return Src;
- // These optimizations require DataLayout.
- if (!DL)
- return nullptr;
-
// See if we can get the length of the input string.
uint64_t Len = GetStringLength(Src);
if (Len == 0)
// We have enough information to now generate the memcpy call to do the
// copy for us. Make a memcpy to copy the nul byte with align = 1.
B.CreateMemCpy(Dst, Src,
- ConstantInt::get(DL->getIntPtrType(CI->getContext()), Len), 1);
+ ConstantInt::get(DL.getIntPtrType(CI->getContext()), Len), 1);
return Dst;
}
// Verify the "stpcpy" function prototype.
FunctionType *FT = Callee->getFunctionType();
- if (!checkStringCopyLibFuncSignature(Callee, LibFunc::stpcpy, DL))
- return nullptr;
-
- // These optimizations require DataLayout.
- if (!DL)
+ if (!checkStringCopyLibFuncSignature(Callee, LibFunc::stpcpy))
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;
+ return StrLen ? B.CreateInBoundsGEP(B.getInt8Ty(), Dst, StrLen) : nullptr;
}
// See if we can get the length of the input string.
return nullptr;
Type *PT = FT->getParamType(0);
- Value *LenV = ConstantInt::get(DL->getIntPtrType(PT), Len);
+ Value *LenV = ConstantInt::get(DL.getIntPtrType(PT), Len);
Value *DstEnd =
- B.CreateGEP(Dst, ConstantInt::get(DL->getIntPtrType(PT), Len - 1));
+ B.CreateGEP(B.getInt8Ty(), Dst, ConstantInt::get(DL.getIntPtrType(PT), Len - 1));
// We have enough information to now generate the memcpy call to do the
// copy for us. Make a memcpy to copy the nul byte with align = 1.
Function *Callee = CI->getCalledFunction();
FunctionType *FT = Callee->getFunctionType();
- if (!checkStringCopyLibFuncSignature(Callee, LibFunc::strncpy, DL))
+ if (!checkStringCopyLibFuncSignature(Callee, LibFunc::strncpy))
return nullptr;
Value *Dst = CI->getArgOperand(0);
if (Len == 0)
return Dst; // strncpy(x, y, 0) -> x
- // These optimizations require DataLayout.
- if (!DL)
- return nullptr;
-
// Let strncpy handle the zero padding
if (Len > SrcLen + 1)
return nullptr;
Type *PT = FT->getParamType(0);
// strncpy(x, s, c) -> memcpy(x, s, c, 1) [s and c are constant]
- B.CreateMemCpy(Dst, Src, ConstantInt::get(DL->getIntPtrType(PT), Len), 1);
+ B.CreateMemCpy(Dst, Src, ConstantInt::get(DL.getIntPtrType(PT), Len), 1);
return Dst;
}
if (I == StringRef::npos) // No match.
return Constant::getNullValue(CI->getType());
- return B.CreateGEP(CI->getArgOperand(0), B.getInt64(I), "strpbrk");
+ return B.CreateGEP(B.getInt8Ty(), CI->getArgOperand(0), B.getInt64(I), "strpbrk");
}
// strpbrk(s, "a") -> strchr(s, 'a')
- if (DL && HasS2 && S2.size() == 1)
- return EmitStrChr(CI->getArgOperand(0), S2[0], B, DL, TLI);
+ if (HasS2 && S2.size() == 1)
+ return EmitStrChr(CI->getArgOperand(0), S2[0], B, TLI);
return nullptr;
}
}
// strcspn(s, "") -> strlen(s)
- if (DL && HasS2 && S2.empty())
+ if (HasS2 && S2.empty())
return EmitStrLen(CI->getArgOperand(0), B, DL, TLI);
return nullptr;
return B.CreateBitCast(CI->getArgOperand(0), CI->getType());
// fold strstr(a, b) == a -> strncmp(a, b, strlen(b)) == 0
- if (DL && isOnlyUsedInEqualityComparison(CI, CI->getArgOperand(0))) {
+ if (isOnlyUsedInEqualityComparison(CI, CI->getArgOperand(0))) {
Value *StrLen = EmitStrLen(CI->getArgOperand(1), B, DL, TLI);
if (!StrLen)
return nullptr;
// fold strstr(x, "y") -> strchr(x, 'y').
if (HasStr2 && ToFindStr.size() == 1) {
- Value *StrChr = EmitStrChr(CI->getArgOperand(0), ToFindStr[0], B, DL, TLI);
+ Value *StrChr = EmitStrChr(CI->getArgOperand(0), ToFindStr[0], B, TLI);
return StrChr ? B.CreateBitCast(StrChr, CI->getType()) : nullptr;
}
return nullptr;
}
+Value *LibCallSimplifier::optimizeMemChr(CallInst *CI, IRBuilder<> &B) {
+ Function *Callee = CI->getCalledFunction();
+ FunctionType *FT = Callee->getFunctionType();
+ if (FT->getNumParams() != 3 || !FT->getParamType(0)->isPointerTy() ||
+ !FT->getParamType(1)->isIntegerTy(32) ||
+ !FT->getParamType(2)->isIntegerTy() ||
+ !FT->getReturnType()->isPointerTy())
+ return nullptr;
+
+ Value *SrcStr = CI->getArgOperand(0);
+ ConstantInt *CharC = dyn_cast<ConstantInt>(CI->getArgOperand(1));
+ ConstantInt *LenC = dyn_cast<ConstantInt>(CI->getArgOperand(2));
+
+ // memchr(x, y, 0) -> null
+ if (LenC && LenC->isNullValue())
+ return Constant::getNullValue(CI->getType());
+
+ // From now on we need at least constant length and string.
+ StringRef Str;
+ if (!LenC || !getConstantStringInfo(SrcStr, Str, 0, /*TrimAtNul=*/false))
+ return nullptr;
+
+ // Truncate the string to LenC. If Str is smaller than LenC we will still only
+ // scan the string, as reading past the end of it is undefined and we can just
+ // return null if we don't find the char.
+ Str = Str.substr(0, LenC->getZExtValue());
+
+ // If the char is variable but the input str and length are not we can turn
+ // this memchr call into a simple bit field test. Of course this only works
+ // when the return value is only checked against null.
+ //
+ // It would be really nice to reuse switch lowering here but we can't change
+ // the CFG at this point.
+ //
+ // memchr("\r\n", C, 2) != nullptr -> (C & ((1 << '\r') | (1 << '\n'))) != 0
+ // after bounds check.
+ if (!CharC && !Str.empty() && isOnlyUsedInZeroEqualityComparison(CI)) {
+ unsigned char Max =
+ *std::max_element(reinterpret_cast<const unsigned char *>(Str.begin()),
+ reinterpret_cast<const unsigned char *>(Str.end()));
+
+ // Make sure the bit field we're about to create fits in a register on the
+ // target.
+ // FIXME: On a 64 bit architecture this prevents us from using the
+ // interesting range of alpha ascii chars. We could do better by emitting
+ // two bitfields or shifting the range by 64 if no lower chars are used.
+ if (!DL.fitsInLegalInteger(Max + 1))
+ return nullptr;
+
+ // For the bit field use a power-of-2 type with at least 8 bits to avoid
+ // creating unnecessary illegal types.
+ unsigned char Width = NextPowerOf2(std::max((unsigned char)7, Max));
+
+ // Now build the bit field.
+ APInt Bitfield(Width, 0);
+ for (char C : Str)
+ Bitfield.setBit((unsigned char)C);
+ Value *BitfieldC = B.getInt(Bitfield);
+
+ // First check that the bit field access is within bounds.
+ Value *C = B.CreateZExtOrTrunc(CI->getArgOperand(1), BitfieldC->getType());
+ Value *Bounds = B.CreateICmp(ICmpInst::ICMP_ULT, C, B.getIntN(Width, Width),
+ "memchr.bounds");
+
+ // Create code that checks if the given bit is set in the field.
+ Value *Shl = B.CreateShl(B.getIntN(Width, 1ULL), C);
+ Value *Bits = B.CreateIsNotNull(B.CreateAnd(Shl, BitfieldC), "memchr.bits");
+
+ // Finally merge both checks and cast to pointer type. The inttoptr
+ // implicitly zexts the i1 to intptr type.
+ return B.CreateIntToPtr(B.CreateAnd(Bounds, Bits, "memchr"), CI->getType());
+ }
+
+ // Check if all arguments are constants. If so, we can constant fold.
+ if (!CharC)
+ return nullptr;
+
+ // Compute the offset.
+ size_t I = Str.find(CharC->getSExtValue() & 0xFF);
+ if (I == StringRef::npos) // Didn't find the char. memchr returns null.
+ return Constant::getNullValue(CI->getType());
+
+ // memchr(s+n,c,l) -> gep(s+n+i,c)
+ return B.CreateGEP(B.getInt8Ty(), SrcStr, B.getInt64(I), "memchr");
+}
+
Value *LibCallSimplifier::optimizeMemCmp(CallInst *CI, IRBuilder<> &B) {
Function *Callee = CI->getCalledFunction();
FunctionType *FT = Callee->getFunctionType();
return B.CreateSub(LHSV, RHSV, "chardiff");
}
+ // memcmp(S1,S2,N/8)==0 -> (*(intN_t*)S1 != *(intN_t*)S2)==0
+ if (DL.isLegalInteger(Len * 8) && isOnlyUsedInZeroEqualityComparison(CI)) {
+
+ IntegerType *IntType = IntegerType::get(CI->getContext(), Len * 8);
+ unsigned PrefAlignment = DL.getPrefTypeAlignment(IntType);
+
+ if (getKnownAlignment(LHS, DL, CI) >= PrefAlignment &&
+ getKnownAlignment(RHS, DL, CI) >= PrefAlignment) {
+
+ Type *LHSPtrTy =
+ IntType->getPointerTo(LHS->getType()->getPointerAddressSpace());
+ Type *RHSPtrTy =
+ IntType->getPointerTo(RHS->getType()->getPointerAddressSpace());
+
+ Value *LHSV = B.CreateLoad(B.CreateBitCast(LHS, LHSPtrTy, "lhsc"), "lhsv");
+ Value *RHSV = B.CreateLoad(B.CreateBitCast(RHS, RHSPtrTy, "rhsc"), "rhsv");
+
+ return B.CreateZExt(B.CreateICmpNE(LHSV, RHSV), CI->getType(), "memcmp");
+ }
+ }
+
// Constant folding: memcmp(x, y, l) -> cnst (all arguments are constant)
StringRef LHSStr, RHSStr;
if (getConstantStringInfo(LHS, LHSStr) &&
Value *LibCallSimplifier::optimizeMemCpy(CallInst *CI, IRBuilder<> &B) {
Function *Callee = CI->getCalledFunction();
- // These optimizations require DataLayout.
- if (!DL)
- return nullptr;
- if (!checkStringCopyLibFuncSignature(Callee, LibFunc::memcpy, DL))
+ if (!checkStringCopyLibFuncSignature(Callee, LibFunc::memcpy))
return nullptr;
// memcpy(x, y, n) -> llvm.memcpy(x, y, n, 1)
Value *LibCallSimplifier::optimizeMemMove(CallInst *CI, IRBuilder<> &B) {
Function *Callee = CI->getCalledFunction();
- // These optimizations require DataLayout.
- if (!DL)
- return nullptr;
- if (!checkStringCopyLibFuncSignature(Callee, LibFunc::memmove, DL))
+ if (!checkStringCopyLibFuncSignature(Callee, LibFunc::memmove))
return nullptr;
// memmove(x, y, n) -> llvm.memmove(x, y, n, 1)
Value *LibCallSimplifier::optimizeMemSet(CallInst *CI, IRBuilder<> &B) {
Function *Callee = CI->getCalledFunction();
- // These optimizations require DataLayout.
- if (!DL)
- return nullptr;
- if (!checkStringCopyLibFuncSignature(Callee, LibFunc::memset, DL))
+ if (!checkStringCopyLibFuncSignature(Callee, LibFunc::memset))
return nullptr;
// memset(p, v, n) -> llvm.memset(p, v, n, 1)
// floor((double)floatval) -> (double)floorf(floatval)
if (Callee->isIntrinsic()) {
Module *M = CI->getParent()->getParent()->getParent();
- Intrinsic::ID IID = (Intrinsic::ID) Callee->getIntrinsicID();
+ Intrinsic::ID IID = Callee->getIntrinsicID();
Function *F = Intrinsic::getDeclaration(M, IID, B.getFloatTy());
V = B.CreateCall(F, V);
} else {
Value *Callee =
M->getOrInsertFunction(TLI->getName(LdExp), Op->getType(),
Op->getType(), B.getInt32Ty(), nullptr);
- CallInst *CI = B.CreateCall2(Callee, One, LdExpArg);
+ CallInst *CI = B.CreateCall(Callee, {One, LdExpArg});
if (const Function *F = dyn_cast<Function>(Callee->stripPointerCasts()))
CI->setCallingConv(F->getCallingConv());
return Ret;
}
+Value *LibCallSimplifier::optimizeFMinFMax(CallInst *CI, IRBuilder<> &B) {
+ // If we can shrink the call to a float function rather than a double
+ // function, do that first.
+ Function *Callee = CI->getCalledFunction();
+ if ((Callee->getName() == "fmin" && TLI->has(LibFunc::fminf)) ||
+ (Callee->getName() == "fmax" && TLI->has(LibFunc::fmaxf))) {
+ Value *Ret = optimizeBinaryDoubleFP(CI, B);
+ if (Ret)
+ return Ret;
+ }
+
+ // Make sure this has 2 arguments of FP type which match the result type.
+ FunctionType *FT = Callee->getFunctionType();
+ if (FT->getNumParams() != 2 || FT->getReturnType() != FT->getParamType(0) ||
+ FT->getParamType(0) != FT->getParamType(1) ||
+ !FT->getParamType(0)->isFloatingPointTy())
+ return nullptr;
+
+ // FIXME: For finer-grain optimization, we need intrinsics to have the same
+ // fast-math flag decorations that are applied to FP instructions. For now,
+ // we have to rely on the function-level attributes to do this optimization
+ // because there's no other way to express that the calls can be relaxed.
+ IRBuilder<>::FastMathFlagGuard Guard(B);
+ FastMathFlags FMF;
+ Function *F = CI->getParent()->getParent();
+ Attribute Attr = F->getFnAttribute("unsafe-fp-math");
+ if (Attr.getValueAsString() == "true") {
+ // Unsafe algebra sets all fast-math-flags to true.
+ FMF.setUnsafeAlgebra();
+ } else {
+ // At a minimum, no-nans-fp-math must be true.
+ Attr = F->getFnAttribute("no-nans-fp-math");
+ if (Attr.getValueAsString() != "true")
+ return nullptr;
+ // No-signed-zeros is implied by the definitions of fmax/fmin themselves:
+ // "Ideally, fmax would be sensitive to the sign of zero, for example
+ // fmax(-0. 0, +0. 0) would return +0; however, implementation in software
+ // might be impractical."
+ FMF.setNoSignedZeros();
+ FMF.setNoNaNs();
+ }
+ B.SetFastMathFlags(FMF);
+
+ // We have a relaxed floating-point environment. We can ignore NaN-handling
+ // and transform to a compare and select. We do not have to consider errno or
+ // exceptions, because fmin/fmax do not have those.
+ Value *Op0 = CI->getArgOperand(0);
+ Value *Op1 = CI->getArgOperand(1);
+ Value *Cmp = Callee->getName().startswith("fmin") ?
+ B.CreateFCmpOLT(Op0, Op1) : B.CreateFCmpOGT(Op0, Op1);
+ return B.CreateSelect(Cmp, Op0, Op1);
+}
+
Value *LibCallSimplifier::optimizeSqrt(CallInst *CI, IRBuilder<> &B) {
Function *Callee = CI->getCalledFunction();
// and multiply.
// FIXME: We're not checking the sqrt because it doesn't have
// fast-math-flags (see earlier comment).
- IRBuilder<true, ConstantFolder,
- IRBuilderDefaultInserter<true> >::FastMathFlagGuard Guard(B);
+ IRBuilder<>::FastMathFlagGuard Guard(B);
B.SetFastMathFlags(I->getFastMathFlags());
// If we found a repeated factor, hoist it out of the square root and
// replace it with the fabs of that factor.
Type *ArgType = Op->getType();
Value *F =
Intrinsic::getDeclaration(Callee->getParent(), Intrinsic::cttz, ArgType);
- Value *V = B.CreateCall2(F, Op, B.getFalse(), "cttz");
+ Value *V = B.CreateCall(F, {Op, B.getTrue()}, "cttz");
V = B.CreateAdd(V, ConstantInt::get(V->getType(), 1));
V = B.CreateIntCast(V, B.getInt32Ty(), false);
// printf("x") -> putchar('x'), even for '%'.
if (FormatStr.size() == 1) {
- Value *Res = EmitPutChar(B.getInt32(FormatStr[0]), B, DL, TLI);
+ Value *Res = EmitPutChar(B.getInt32(FormatStr[0]), B, TLI);
if (CI->use_empty() || !Res)
return Res;
return B.CreateIntCast(Res, CI->getType(), true);
// pass to be run after this pass, to merge duplicate strings.
FormatStr = FormatStr.drop_back();
Value *GV = B.CreateGlobalString(FormatStr, "str");
- Value *NewCI = EmitPutS(GV, B, DL, TLI);
+ Value *NewCI = EmitPutS(GV, B, TLI);
return (CI->use_empty() || !NewCI)
? NewCI
: ConstantInt::get(CI->getType(), FormatStr.size() + 1);
// printf("%c", chr) --> putchar(chr)
if (FormatStr == "%c" && CI->getNumArgOperands() > 1 &&
CI->getArgOperand(1)->getType()->isIntegerTy()) {
- Value *Res = EmitPutChar(CI->getArgOperand(1), B, DL, TLI);
+ Value *Res = EmitPutChar(CI->getArgOperand(1), B, TLI);
if (CI->use_empty() || !Res)
return Res;
// printf("%s\n", str) --> puts(str)
if (FormatStr == "%s\n" && CI->getNumArgOperands() > 1 &&
CI->getArgOperand(1)->getType()->isPointerTy()) {
- return EmitPutS(CI->getArgOperand(1), B, DL, TLI);
+ return EmitPutS(CI->getArgOperand(1), B, TLI);
}
return nullptr;
}
if (FormatStr[i] == '%')
return nullptr; // we found a format specifier, bail out.
- // These optimizations require DataLayout.
- if (!DL)
- return nullptr;
-
// sprintf(str, fmt) -> llvm.memcpy(str, fmt, strlen(fmt)+1, 1)
- B.CreateMemCpy(
- CI->getArgOperand(0), CI->getArgOperand(1),
- ConstantInt::get(DL->getIntPtrType(CI->getContext()),
- FormatStr.size() + 1),
- 1); // Copy the null byte.
+ B.CreateMemCpy(CI->getArgOperand(0), CI->getArgOperand(1),
+ ConstantInt::get(DL.getIntPtrType(CI->getContext()),
+ FormatStr.size() + 1),
+ 1); // Copy the null byte.
return ConstantInt::get(CI->getType(), FormatStr.size());
}
Value *V = B.CreateTrunc(CI->getArgOperand(2), B.getInt8Ty(), "char");
Value *Ptr = CastToCStr(CI->getArgOperand(0), B);
B.CreateStore(V, Ptr);
- Ptr = B.CreateGEP(Ptr, B.getInt32(1), "nul");
+ Ptr = B.CreateGEP(B.getInt8Ty(), Ptr, B.getInt32(1), "nul");
B.CreateStore(B.getInt8(0), Ptr);
return ConstantInt::get(CI->getType(), 1);
}
if (FormatStr[1] == 's') {
- // These optimizations require DataLayout.
- if (!DL)
- return nullptr;
-
// sprintf(dest, "%s", str) -> llvm.memcpy(dest, str, strlen(str)+1, 1)
if (!CI->getArgOperand(2)->getType()->isPointerTy())
return nullptr;
if (FormatStr[i] == '%') // Could handle %% -> % if we cared.
return nullptr; // We found a format specifier.
- // These optimizations require DataLayout.
- if (!DL)
- return nullptr;
-
return EmitFWrite(
CI->getArgOperand(1),
- ConstantInt::get(DL->getIntPtrType(CI->getContext()), FormatStr.size()),
+ ConstantInt::get(DL.getIntPtrType(CI->getContext()), FormatStr.size()),
CI->getArgOperand(0), B, DL, TLI);
}
// fprintf(F, "%c", chr) --> fputc(chr, F)
if (!CI->getArgOperand(2)->getType()->isIntegerTy())
return nullptr;
- return EmitFPutC(CI->getArgOperand(2), CI->getArgOperand(0), B, DL, TLI);
+ return EmitFPutC(CI->getArgOperand(2), CI->getArgOperand(0), B, TLI);
}
if (FormatStr[1] == 's') {
// fprintf(F, "%s", str) --> fputs(str, F)
if (!CI->getArgOperand(2)->getType()->isPointerTy())
return nullptr;
- return EmitFPutS(CI->getArgOperand(2), CI->getArgOperand(0), B, DL, TLI);
+ return EmitFPutS(CI->getArgOperand(2), CI->getArgOperand(0), B, TLI);
}
return nullptr;
}
// This optimisation is only valid, if the return value is unused.
if (Bytes == 1 && CI->use_empty()) { // fwrite(S,1,1,F) -> fputc(S[0],F)
Value *Char = B.CreateLoad(CastToCStr(CI->getArgOperand(0), B), "char");
- Value *NewCI = EmitFPutC(Char, CI->getArgOperand(3), B, DL, TLI);
+ Value *NewCI = EmitFPutC(Char, CI->getArgOperand(3), B, TLI);
return NewCI ? ConstantInt::get(CI->getType(), 1) : nullptr;
}
Function *Callee = CI->getCalledFunction();
- // These optimizations require DataLayout.
- if (!DL)
- return nullptr;
-
// Require two pointers. Also, we can't optimize if return value is used.
FunctionType *FT = Callee->getFunctionType();
if (FT->getNumParams() != 2 || !FT->getParamType(0)->isPointerTy() ||
// Known to have no uses (see above).
return EmitFWrite(
CI->getArgOperand(0),
- ConstantInt::get(DL->getIntPtrType(CI->getContext()), Len - 1),
+ ConstantInt::get(DL.getIntPtrType(CI->getContext()), Len - 1),
CI->getArgOperand(1), B, DL, TLI);
}
if (Str.empty() && CI->use_empty()) {
// puts("") -> putchar('\n')
- Value *Res = EmitPutChar(B.getInt32('\n'), B, DL, TLI);
+ Value *Res = EmitPutChar(B.getInt32('\n'), B, TLI);
if (CI->use_empty() || !Res)
return Res;
return B.CreateIntCast(Res, CI->getType(), true);
return false;
}
-Value *LibCallSimplifier::optimizeCall(CallInst *CI) {
- if (CI->isNoBuiltin())
- return nullptr;
-
+Value *LibCallSimplifier::optimizeStringMemoryLibCall(CallInst *CI,
+ IRBuilder<> &Builder) {
LibFunc::Func Func;
Function *Callee = CI->getCalledFunction();
StringRef FuncName = Callee->getName();
- IRBuilder<> Builder(CI);
- bool isCallingConvC = CI->getCallingConv() == llvm::CallingConv::C;
-
- // Command-line parameter overrides function attribute.
- if (EnableUnsafeFPShrink.getNumOccurrences() > 0)
- UnsafeFPShrink = EnableUnsafeFPShrink;
- else if (Callee->hasFnAttribute("unsafe-fp-math")) {
- // FIXME: This is the same problem as described in optimizeSqrt().
- // If calls gain access to IR-level FMF, then use that instead of a
- // function attribute.
-
- // Check for unsafe-fp-math = true.
- Attribute Attr = Callee->getFnAttribute("unsafe-fp-math");
- if (Attr.getValueAsString() == "true")
- UnsafeFPShrink = true;
- }
-
- // First, check for intrinsics.
- if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(CI)) {
- if (!isCallingConvC)
- return nullptr;
- switch (II->getIntrinsicID()) {
- case Intrinsic::pow:
- return optimizePow(CI, Builder);
- case Intrinsic::exp2:
- return optimizeExp2(CI, Builder);
- case Intrinsic::fabs:
- return optimizeFabs(CI, Builder);
- case Intrinsic::sqrt:
- return optimizeSqrt(CI, Builder);
- default:
- return nullptr;
- }
- }
- // Then check for known library functions.
+ // Check for string/memory library functions.
if (TLI->getLibFunc(FuncName, Func) && TLI->has(Func)) {
- // We never change the calling convention.
- if (!ignoreCallingConv(Func) && !isCallingConvC)
- return nullptr;
+ // Make sure we never change the calling convention.
+ assert((ignoreCallingConv(Func) ||
+ CI->getCallingConv() == llvm::CallingConv::C) &&
+ "Optimizing string/memory libcall would change the calling convention");
switch (Func) {
case LibFunc::strcat:
return optimizeStrCat(CI, Builder);
return optimizeStrCSpn(CI, Builder);
case LibFunc::strstr:
return optimizeStrStr(CI, Builder);
+ case LibFunc::memchr:
+ return optimizeMemChr(CI, Builder);
case LibFunc::memcmp:
return optimizeMemCmp(CI, Builder);
case LibFunc::memcpy:
return optimizeMemMove(CI, Builder);
case LibFunc::memset:
return optimizeMemSet(CI, Builder);
+ default:
+ break;
+ }
+ }
+ return nullptr;
+}
+
+Value *LibCallSimplifier::optimizeCall(CallInst *CI) {
+ if (CI->isNoBuiltin())
+ return nullptr;
+
+ LibFunc::Func Func;
+ Function *Callee = CI->getCalledFunction();
+ StringRef FuncName = Callee->getName();
+ IRBuilder<> Builder(CI);
+ bool isCallingConvC = CI->getCallingConv() == llvm::CallingConv::C;
+
+ // Command-line parameter overrides function attribute.
+ if (EnableUnsafeFPShrink.getNumOccurrences() > 0)
+ UnsafeFPShrink = EnableUnsafeFPShrink;
+ else if (Callee->hasFnAttribute("unsafe-fp-math")) {
+ // FIXME: This is the same problem as described in optimizeSqrt().
+ // If calls gain access to IR-level FMF, then use that instead of a
+ // function attribute.
+
+ // Check for unsafe-fp-math = true.
+ Attribute Attr = Callee->getFnAttribute("unsafe-fp-math");
+ if (Attr.getValueAsString() == "true")
+ UnsafeFPShrink = true;
+ }
+
+ // First, check for intrinsics.
+ if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(CI)) {
+ if (!isCallingConvC)
+ return nullptr;
+ switch (II->getIntrinsicID()) {
+ case Intrinsic::pow:
+ return optimizePow(CI, Builder);
+ case Intrinsic::exp2:
+ return optimizeExp2(CI, Builder);
+ case Intrinsic::fabs:
+ return optimizeFabs(CI, Builder);
+ case Intrinsic::sqrt:
+ return optimizeSqrt(CI, Builder);
+ default:
+ return nullptr;
+ }
+ }
+
+ // Also try to simplify calls to fortified library functions.
+ if (Value *SimplifiedFortifiedCI = FortifiedSimplifier.optimizeCall(CI)) {
+ // Try to further simplify the result.
+ CallInst *SimplifiedCI = dyn_cast<CallInst>(SimplifiedFortifiedCI);
+ if (SimplifiedCI && SimplifiedCI->getCalledFunction())
+ if (Value *V = optimizeStringMemoryLibCall(SimplifiedCI, Builder)) {
+ // If we were able to further simplify, remove the now redundant call.
+ SimplifiedCI->replaceAllUsesWith(V);
+ SimplifiedCI->eraseFromParent();
+ return V;
+ }
+ return SimplifiedFortifiedCI;
+ }
+
+ // Then check for known library functions.
+ if (TLI->getLibFunc(FuncName, Func) && TLI->has(Func)) {
+ // We never change the calling convention.
+ if (!ignoreCallingConv(Func) && !isCallingConvC)
+ return nullptr;
+ if (Value *V = optimizeStringMemoryLibCall(CI, Builder))
+ return V;
+ switch (Func) {
case LibFunc::cosf:
case LibFunc::cos:
case LibFunc::cosl:
return optimizeUnaryDoubleFP(CI, Builder, true);
return nullptr;
case LibFunc::copysign:
- case LibFunc::fmin:
- case LibFunc::fmax:
if (hasFloatVersion(FuncName))
return optimizeBinaryDoubleFP(CI, Builder);
return nullptr;
- case LibFunc::memcpy_chk:
- return optimizeMemCpyChk(CI, Builder);
- case LibFunc::memmove_chk:
- return optimizeMemMoveChk(CI, Builder);
- case LibFunc::memset_chk:
- return optimizeMemSetChk(CI, Builder);
- case LibFunc::strcpy_chk:
- return optimizeStrCpyChk(CI, Builder);
- case LibFunc::stpcpy_chk:
- return optimizeStpCpyChk(CI, Builder);
- case LibFunc::stpncpy_chk:
- case LibFunc::strncpy_chk:
- return optimizeStrNCpyChk(CI, Builder);
+ case LibFunc::fminf:
+ case LibFunc::fmin:
+ case LibFunc::fminl:
+ case LibFunc::fmaxf:
+ case LibFunc::fmax:
+ case LibFunc::fmaxl:
+ return optimizeFMinFMax(CI, Builder);
default:
return nullptr;
}
}
-
return nullptr;
}
-LibCallSimplifier::LibCallSimplifier(const DataLayout *DL,
- const TargetLibraryInfo *TLI) :
- DL(DL),
- TLI(TLI),
- UnsafeFPShrink(false) {
+LibCallSimplifier::LibCallSimplifier(
+ const DataLayout &DL, const TargetLibraryInfo *TLI,
+ function_ref<void(Instruction *, Value *)> Replacer)
+ : FortifiedSimplifier(TLI), DL(DL), TLI(TLI), UnsafeFPShrink(false),
+ Replacer(Replacer) {}
+
+void LibCallSimplifier::replaceAllUsesWith(Instruction *I, Value *With) {
+ // Indirect through the replacer used in this instance.
+ Replacer(I, With);
}
-void LibCallSimplifier::replaceAllUsesWith(Instruction *I, Value *With) const {
+/*static*/ void LibCallSimplifier::replaceAllUsesWithDefault(Instruction *I,
+ Value *With) {
I->replaceAllUsesWith(With);
I->eraseFromParent();
}
// cbrt:
// * cbrt(expN(X)) -> expN(x/3)
// * cbrt(sqrt(x)) -> pow(x,1/6)
-// * cbrt(sqrt(x)) -> pow(x,1/9)
+// * cbrt(cbrt(x)) -> pow(x,1/9)
//
// exp, expf, expl:
// * exp(log(x)) -> x
// * trunc(cnst) -> cnst'
//
//
+
+//===----------------------------------------------------------------------===//
+// Fortified Library Call Optimizations
+//===----------------------------------------------------------------------===//
+
+bool FortifiedLibCallSimplifier::isFortifiedCallFoldable(CallInst *CI,
+ unsigned ObjSizeOp,
+ unsigned SizeOp,
+ bool isString) {
+ if (CI->getArgOperand(ObjSizeOp) == CI->getArgOperand(SizeOp))
+ return true;
+ if (ConstantInt *ObjSizeCI =
+ dyn_cast<ConstantInt>(CI->getArgOperand(ObjSizeOp))) {
+ if (ObjSizeCI->isAllOnesValue())
+ return true;
+ // If the object size wasn't -1 (unknown), bail out if we were asked to.
+ if (OnlyLowerUnknownSize)
+ return false;
+ if (isString) {
+ uint64_t Len = GetStringLength(CI->getArgOperand(SizeOp));
+ // 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 ObjSizeCI->getZExtValue() >= Len;
+ }
+ if (ConstantInt *SizeCI = dyn_cast<ConstantInt>(CI->getArgOperand(SizeOp)))
+ return ObjSizeCI->getZExtValue() >= SizeCI->getZExtValue();
+ }
+ return false;
+}
+
+Value *FortifiedLibCallSimplifier::optimizeMemCpyChk(CallInst *CI, IRBuilder<> &B) {
+ Function *Callee = CI->getCalledFunction();
+
+ if (!checkStringCopyLibFuncSignature(Callee, LibFunc::memcpy_chk))
+ 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 *FortifiedLibCallSimplifier::optimizeMemMoveChk(CallInst *CI, IRBuilder<> &B) {
+ Function *Callee = CI->getCalledFunction();
+
+ if (!checkStringCopyLibFuncSignature(Callee, LibFunc::memmove_chk))
+ 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 *FortifiedLibCallSimplifier::optimizeMemSetChk(CallInst *CI, IRBuilder<> &B) {
+ Function *Callee = CI->getCalledFunction();
+
+ if (!checkStringCopyLibFuncSignature(Callee, LibFunc::memset_chk))
+ 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 *FortifiedLibCallSimplifier::optimizeStrpCpyChk(CallInst *CI,
+ IRBuilder<> &B,
+ LibFunc::Func Func) {
+ Function *Callee = CI->getCalledFunction();
+ StringRef Name = Callee->getName();
+ const DataLayout &DL = CI->getModule()->getDataLayout();
+
+ if (!checkStringCopyLibFuncSignature(Callee, Func))
+ return nullptr;
+
+ Value *Dst = CI->getArgOperand(0), *Src = CI->getArgOperand(1),
+ *ObjSize = CI->getArgOperand(2);
+
+ // __stpcpy_chk(x,x,...) -> x+strlen(x)
+ if (Func == LibFunc::stpcpy_chk && !OnlyLowerUnknownSize && Dst == Src) {
+ Value *StrLen = EmitStrLen(Src, B, DL, TLI);
+ return StrLen ? B.CreateInBoundsGEP(B.getInt8Ty(), 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 st[rp]cpy. Otherwise we'll keep our
+ // st[rp]cpy_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))
+ return EmitStrCpy(Dst, Src, B, TLI, Name.substr(2, 6));
+
+ if (OnlyLowerUnknownSize)
+ return nullptr;
+
+ // Maybe we can stil fold __st[rp]cpy_chk to __memcpy_chk.
+ uint64_t Len = GetStringLength(Src);
+ if (Len == 0)
+ return nullptr;
+
+ Type *SizeTTy = DL.getIntPtrType(CI->getContext());
+ Value *LenV = ConstantInt::get(SizeTTy, Len);
+ Value *Ret = EmitMemCpyChk(Dst, Src, LenV, ObjSize, B, DL, TLI);
+ // If the function was an __stpcpy_chk, and we were able to fold it into
+ // a __memcpy_chk, we still need to return the correct end pointer.
+ if (Ret && Func == LibFunc::stpcpy_chk)
+ return B.CreateGEP(B.getInt8Ty(), Dst, ConstantInt::get(SizeTTy, Len - 1));
+ return Ret;
+}
+
+Value *FortifiedLibCallSimplifier::optimizeStrpNCpyChk(CallInst *CI,
+ IRBuilder<> &B,
+ LibFunc::Func Func) {
+ Function *Callee = CI->getCalledFunction();
+ StringRef Name = Callee->getName();
+
+ if (!checkStringCopyLibFuncSignature(Callee, Func))
+ return nullptr;
+ if (isFortifiedCallFoldable(CI, 3, 2, false)) {
+ Value *Ret = EmitStrNCpy(CI->getArgOperand(0), CI->getArgOperand(1),
+ CI->getArgOperand(2), B, TLI, Name.substr(2, 7));
+ return Ret;
+ }
+ return nullptr;
+}
+
+Value *FortifiedLibCallSimplifier::optimizeCall(CallInst *CI) {
+ // FIXME: We shouldn't be changing "nobuiltin" or TLI unavailable calls here.
+ // Some clang users checked for _chk libcall availability using:
+ // __has_builtin(__builtin___memcpy_chk)
+ // When compiling with -fno-builtin, this is always true.
+ // When passing -ffreestanding/-mkernel, which both imply -fno-builtin, we
+ // end up with fortified libcalls, which isn't acceptable in a freestanding
+ // environment which only provides their non-fortified counterparts.
+ //
+ // Until we change clang and/or teach external users to check for availability
+ // differently, disregard the "nobuiltin" attribute and TLI::has.
+ //
+ // PR23093.
+
+ LibFunc::Func Func;
+ Function *Callee = CI->getCalledFunction();
+ StringRef FuncName = Callee->getName();
+ IRBuilder<> Builder(CI);
+ bool isCallingConvC = CI->getCallingConv() == llvm::CallingConv::C;
+
+ // First, check that this is a known library functions.
+ if (!TLI->getLibFunc(FuncName, Func))
+ return nullptr;
+
+ // We never change the calling convention.
+ if (!ignoreCallingConv(Func) && !isCallingConvC)
+ return nullptr;
+
+ switch (Func) {
+ case LibFunc::memcpy_chk:
+ return optimizeMemCpyChk(CI, Builder);
+ case LibFunc::memmove_chk:
+ return optimizeMemMoveChk(CI, Builder);
+ case LibFunc::memset_chk:
+ return optimizeMemSetChk(CI, Builder);
+ case LibFunc::stpcpy_chk:
+ case LibFunc::strcpy_chk:
+ return optimizeStrpCpyChk(CI, Builder, Func);
+ case LibFunc::stpncpy_chk:
+ case LibFunc::strncpy_chk:
+ return optimizeStrpNCpyChk(CI, Builder, Func);
+ default:
+ break;
+ }
+ return nullptr;
+}
+
+FortifiedLibCallSimplifier::FortifiedLibCallSimplifier(
+ const TargetLibraryInfo *TLI, bool OnlyLowerUnknownSize)
+ : TLI(TLI), OnlyLowerUnknownSize(OnlyLowerUnknownSize) {}
projects / oota-llvm.git / blobdiff