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Diffstat (limited to 'contrib/llvm/lib/Transforms/Scalar/SimplifyLibCalls.cpp')
| -rw-r--r-- | contrib/llvm/lib/Transforms/Scalar/SimplifyLibCalls.cpp | 2476 |
1 files changed, 2476 insertions, 0 deletions
diff --git a/contrib/llvm/lib/Transforms/Scalar/SimplifyLibCalls.cpp b/contrib/llvm/lib/Transforms/Scalar/SimplifyLibCalls.cpp new file mode 100644 index 0000000..f110320 --- /dev/null +++ b/contrib/llvm/lib/Transforms/Scalar/SimplifyLibCalls.cpp @@ -0,0 +1,2476 @@ +//===- SimplifyLibCalls.cpp - Optimize specific well-known library calls --===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file implements a simple pass that applies a variety of small +// optimizations for calls to specific well-known function calls (e.g. runtime +// library functions). Any optimization that takes the very simple form +// "replace call to library function with simpler code that provides the same +// result" belongs in this file. +// +//===----------------------------------------------------------------------===// + +#define DEBUG_TYPE "simplify-libcalls" +#include "llvm/Transforms/Scalar.h" +#include "llvm/Transforms/Utils/BuildLibCalls.h" +#include "llvm/IRBuilder.h" +#include "llvm/Intrinsics.h" +#include "llvm/LLVMContext.h" +#include "llvm/Module.h" +#include "llvm/Pass.h" +#include "llvm/ADT/STLExtras.h" +#include "llvm/ADT/SmallPtrSet.h" +#include "llvm/ADT/Statistic.h" +#include "llvm/ADT/StringMap.h" +#include "llvm/Analysis/ValueTracking.h" +#include "llvm/Support/Debug.h" +#include "llvm/Support/raw_ostream.h" +#include "llvm/Target/TargetData.h" +#include "llvm/Target/TargetLibraryInfo.h" +#include "llvm/Config/config.h" // FIXME: Shouldn't depend on host! +using namespace llvm; + +STATISTIC(NumSimplified, "Number of library calls simplified"); +STATISTIC(NumAnnotated, "Number of attributes added to library functions"); + +//===----------------------------------------------------------------------===// +// Optimizer Base Class +//===----------------------------------------------------------------------===// + +/// This class is the abstract base class for the set of optimizations that +/// corresponds to one library call. +namespace { +class LibCallOptimization { +protected: + Function *Caller; + const TargetData *TD; + const TargetLibraryInfo *TLI; + LLVMContext* Context; +public: + LibCallOptimization() { } + virtual ~LibCallOptimization() {} + + /// CallOptimizer - This pure virtual method is implemented by base classes to + /// do various optimizations. If this returns null then no transformation was + /// performed. If it returns CI, then it transformed the call and CI is to be + /// deleted. If it returns something else, replace CI with the new value and + /// delete CI. + virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) + =0; + + Value *OptimizeCall(CallInst *CI, const TargetData *TD, + const TargetLibraryInfo *TLI, IRBuilder<> &B) { + Caller = CI->getParent()->getParent(); + this->TD = TD; + this->TLI = TLI; + if (CI->getCalledFunction()) + Context = &CI->getCalledFunction()->getContext(); + + // We never change the calling convention. + if (CI->getCallingConv() != llvm::CallingConv::C) + return NULL; + + return CallOptimizer(CI->getCalledFunction(), CI, B); + } +}; +} // End anonymous namespace. + + +//===----------------------------------------------------------------------===// +// Helper Functions +//===----------------------------------------------------------------------===// + +/// IsOnlyUsedInZeroEqualityComparison - Return true if it only matters that the +/// value is equal or not-equal to zero. +static bool IsOnlyUsedInZeroEqualityComparison(Value *V) { + for (Value::use_iterator UI = V->use_begin(), E = V->use_end(); + UI != E; ++UI) { + if (ICmpInst *IC = dyn_cast<ICmpInst>(*UI)) + if (IC->isEquality()) + if (Constant *C = dyn_cast<Constant>(IC->getOperand(1))) + if (C->isNullValue()) + continue; + // Unknown instruction. + return false; + } + return true; +} + +static bool CallHasFloatingPointArgument(const CallInst *CI) { + for (CallInst::const_op_iterator it = CI->op_begin(), e = CI->op_end(); + it != e; ++it) { + if ((*it)->getType()->isFloatingPointTy()) + return true; + } + return false; +} + +/// IsOnlyUsedInEqualityComparison - Return true if it is only used in equality +/// comparisons with With. +static bool IsOnlyUsedInEqualityComparison(Value *V, Value *With) { + for (Value::use_iterator UI = V->use_begin(), E = V->use_end(); + UI != E; ++UI) { + if (ICmpInst *IC = dyn_cast<ICmpInst>(*UI)) + if (IC->isEquality() && IC->getOperand(1) == With) + continue; + // Unknown instruction. + return false; + } + return true; +} + +//===----------------------------------------------------------------------===// +// String and Memory LibCall Optimizations +//===----------------------------------------------------------------------===// + +//===---------------------------------------===// +// 'strcat' Optimizations +namespace { +struct StrCatOpt : public LibCallOptimization { + virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) { + // Verify the "strcat" function prototype. + FunctionType *FT = Callee->getFunctionType(); + if (FT->getNumParams() != 2 || + FT->getReturnType() != B.getInt8PtrTy() || + FT->getParamType(0) != FT->getReturnType() || + FT->getParamType(1) != FT->getReturnType()) + return 0; + + // Extract some information from the instruction + Value *Dst = CI->getArgOperand(0); + Value *Src = CI->getArgOperand(1); + + // See if we can get the length of the input string. + uint64_t Len = GetStringLength(Src); + if (Len == 0) return 0; + --Len; // Unbias length. + + // Handle the simple, do-nothing case: strcat(x, "") -> x + if (Len == 0) + return Dst; + + // These optimizations require TargetData. + if (!TD) return 0; + + return EmitStrLenMemCpy(Src, Dst, Len, B); + } + + Value *EmitStrLenMemCpy(Value *Src, Value *Dst, uint64_t Len, IRBuilder<> &B) { + // We need to find the end of the destination string. That's where the + // memory is to be moved to. We just generate a call to strlen. + Value *DstLen = EmitStrLen(Dst, B, TD, TLI); + if (!DstLen) + return 0; + + // 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"); + + // 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(TD->getIntPtrType(*Context), Len + 1), 1); + return Dst; + } +}; + +//===---------------------------------------===// +// 'strncat' Optimizations + +struct StrNCatOpt : public StrCatOpt { + virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) { + // Verify the "strncat" function prototype. + FunctionType *FT = Callee->getFunctionType(); + if (FT->getNumParams() != 3 || + FT->getReturnType() != B.getInt8PtrTy() || + FT->getParamType(0) != FT->getReturnType() || + FT->getParamType(1) != FT->getReturnType() || + !FT->getParamType(2)->isIntegerTy()) + return 0; + + // Extract some information from the instruction + Value *Dst = CI->getArgOperand(0); + Value *Src = CI->getArgOperand(1); + uint64_t Len; + + // We don't do anything if length is not constant + if (ConstantInt *LengthArg = dyn_cast<ConstantInt>(CI->getArgOperand(2))) + Len = LengthArg->getZExtValue(); + else + return 0; + + // See if we can get the length of the input string. + uint64_t SrcLen = GetStringLength(Src); + if (SrcLen == 0) return 0; + --SrcLen; // Unbias length. + + // Handle the simple, do-nothing cases: + // strncat(x, "", c) -> x + // strncat(x, c, 0) -> x + if (SrcLen == 0 || Len == 0) return Dst; + + // These optimizations require TargetData. + if (!TD) return 0; + + // We don't optimize this case + if (Len < SrcLen) return 0; + + // strncat(x, s, c) -> strcat(x, s) + // s is constant so the strcat can be optimized further + return EmitStrLenMemCpy(Src, Dst, SrcLen, B); + } +}; + +//===---------------------------------------===// +// 'strchr' Optimizations + +struct StrChrOpt : public LibCallOptimization { + virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) { + // Verify the "strchr" function prototype. + FunctionType *FT = Callee->getFunctionType(); + if (FT->getNumParams() != 2 || + FT->getReturnType() != B.getInt8PtrTy() || + FT->getParamType(0) != FT->getReturnType() || + !FT->getParamType(1)->isIntegerTy(32)) + return 0; + + Value *SrcStr = CI->getArgOperand(0); + + // If the second operand is non-constant, see if we can compute the length + // of the input string and turn this into memchr. + ConstantInt *CharC = dyn_cast<ConstantInt>(CI->getArgOperand(1)); + if (CharC == 0) { + // These optimizations require TargetData. + if (!TD) return 0; + + uint64_t Len = GetStringLength(SrcStr); + if (Len == 0 || !FT->getParamType(1)->isIntegerTy(32))// memchr needs i32. + return 0; + + return EmitMemChr(SrcStr, CI->getArgOperand(1), // include nul. + ConstantInt::get(TD->getIntPtrType(*Context), Len), + B, TD, 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)) + return 0; + + // Compute the offset, make sure to handle the case when we're searching for + // zero (a weird way to spell strlen). + size_t I = CharC->getSExtValue() == 0 ? + Str.size() : Str.find(CharC->getSExtValue()); + if (I == StringRef::npos) // Didn't find the char. strchr returns null. + return Constant::getNullValue(CI->getType()); + + // strchr(s+n,c) -> gep(s+n+i,c) + return B.CreateGEP(SrcStr, B.getInt64(I), "strchr"); + } +}; + +//===---------------------------------------===// +// 'strrchr' Optimizations + +struct StrRChrOpt : public LibCallOptimization { + virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) { + // Verify the "strrchr" function prototype. + FunctionType *FT = Callee->getFunctionType(); + if (FT->getNumParams() != 2 || + FT->getReturnType() != B.getInt8PtrTy() || + FT->getParamType(0) != FT->getReturnType() || + !FT->getParamType(1)->isIntegerTy(32)) + return 0; + + Value *SrcStr = CI->getArgOperand(0); + ConstantInt *CharC = dyn_cast<ConstantInt>(CI->getArgOperand(1)); + + // Cannot fold anything if we're not looking for a constant. + if (!CharC) + return 0; + + StringRef Str; + if (!getConstantStringInfo(SrcStr, Str)) { + // strrchr(s, 0) -> strchr(s, 0) + if (TD && CharC->isZero()) + return EmitStrChr(SrcStr, '\0', B, TD, TLI); + return 0; + } + + // Compute the offset. + size_t I = CharC->getSExtValue() == 0 ? + Str.size() : Str.rfind(CharC->getSExtValue()); + if (I == StringRef::npos) // Didn't find the char. Return null. + return Constant::getNullValue(CI->getType()); + + // strrchr(s+n,c) -> gep(s+n+i,c) + return B.CreateGEP(SrcStr, B.getInt64(I), "strrchr"); + } +}; + +//===---------------------------------------===// +// 'strcmp' Optimizations + +struct StrCmpOpt : public LibCallOptimization { + virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) { + // Verify the "strcmp" function prototype. + FunctionType *FT = Callee->getFunctionType(); + if (FT->getNumParams() != 2 || + !FT->getReturnType()->isIntegerTy(32) || + FT->getParamType(0) != FT->getParamType(1) || + FT->getParamType(0) != B.getInt8PtrTy()) + return 0; + + Value *Str1P = CI->getArgOperand(0), *Str2P = CI->getArgOperand(1); + if (Str1P == Str2P) // strcmp(x,x) -> 0 + return ConstantInt::get(CI->getType(), 0); + + StringRef Str1, Str2; + bool HasStr1 = getConstantStringInfo(Str1P, Str1); + bool HasStr2 = getConstantStringInfo(Str2P, Str2); + + // strcmp(x, y) -> cnst (if both x and y are constant strings) + if (HasStr1 && HasStr2) + return ConstantInt::get(CI->getType(), Str1.compare(Str2)); + + if (HasStr1 && Str1.empty()) // strcmp("", x) -> -*x + return B.CreateNeg(B.CreateZExt(B.CreateLoad(Str2P, "strcmpload"), + CI->getType())); + + if (HasStr2 && Str2.empty()) // strcmp(x,"") -> *x + return B.CreateZExt(B.CreateLoad(Str1P, "strcmpload"), CI->getType()); + + // strcmp(P, "x") -> memcmp(P, "x", 2) + uint64_t Len1 = GetStringLength(Str1P); + uint64_t Len2 = GetStringLength(Str2P); + if (Len1 && Len2) { + // These optimizations require TargetData. + if (!TD) return 0; + + return EmitMemCmp(Str1P, Str2P, + ConstantInt::get(TD->getIntPtrType(*Context), + std::min(Len1, Len2)), B, TD, TLI); + } + + return 0; + } +}; + +//===---------------------------------------===// +// 'strncmp' Optimizations + +struct StrNCmpOpt : public LibCallOptimization { + virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) { + // Verify the "strncmp" function prototype. + FunctionType *FT = Callee->getFunctionType(); + if (FT->getNumParams() != 3 || + !FT->getReturnType()->isIntegerTy(32) || + FT->getParamType(0) != FT->getParamType(1) || + FT->getParamType(0) != B.getInt8PtrTy() || + !FT->getParamType(2)->isIntegerTy()) + return 0; + + Value *Str1P = CI->getArgOperand(0), *Str2P = CI->getArgOperand(1); + if (Str1P == Str2P) // strncmp(x,x,n) -> 0 + return ConstantInt::get(CI->getType(), 0); + + // Get the length argument if it is constant. + uint64_t Length; + if (ConstantInt *LengthArg = dyn_cast<ConstantInt>(CI->getArgOperand(2))) + Length = LengthArg->getZExtValue(); + else + return 0; + + if (Length == 0) // strncmp(x,y,0) -> 0 + return ConstantInt::get(CI->getType(), 0); + + if (TD && Length == 1) // strncmp(x,y,1) -> memcmp(x,y,1) + return EmitMemCmp(Str1P, Str2P, CI->getArgOperand(2), B, TD, TLI); + + StringRef Str1, Str2; + bool HasStr1 = getConstantStringInfo(Str1P, Str1); + bool HasStr2 = getConstantStringInfo(Str2P, Str2); + + // strncmp(x, y) -> cnst (if both x and y are constant strings) + if (HasStr1 && HasStr2) { + StringRef SubStr1 = Str1.substr(0, Length); + StringRef SubStr2 = Str2.substr(0, Length); + return ConstantInt::get(CI->getType(), SubStr1.compare(SubStr2)); + } + + if (HasStr1 && Str1.empty()) // strncmp("", x, n) -> -*x + return B.CreateNeg(B.CreateZExt(B.CreateLoad(Str2P, "strcmpload"), + CI->getType())); + + if (HasStr2 && Str2.empty()) // strncmp(x, "", n) -> *x + return B.CreateZExt(B.CreateLoad(Str1P, "strcmpload"), CI->getType()); + + return 0; + } +}; + + +//===---------------------------------------===// +// 'strcpy' Optimizations + +struct StrCpyOpt : public LibCallOptimization { + bool OptChkCall; // True if it's optimizing a __strcpy_chk libcall. + + StrCpyOpt(bool c) : OptChkCall(c) {} + + virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) { + // Verify the "strcpy" function prototype. + unsigned NumParams = OptChkCall ? 3 : 2; + FunctionType *FT = Callee->getFunctionType(); + if (FT->getNumParams() != NumParams || + FT->getReturnType() != FT->getParamType(0) || + FT->getParamType(0) != FT->getParamType(1) || + FT->getParamType(0) != B.getInt8PtrTy()) + return 0; + + Value *Dst = CI->getArgOperand(0), *Src = CI->getArgOperand(1); + if (Dst == Src) // strcpy(x,x) -> x + return Src; + + // These optimizations require TargetData. + if (!TD) return 0; + + // See if we can get the length of the input string. + uint64_t Len = GetStringLength(Src); + if (Len == 0) return 0; + + // 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. + if (!OptChkCall || + !EmitMemCpyChk(Dst, Src, + ConstantInt::get(TD->getIntPtrType(*Context), Len), + CI->getArgOperand(2), B, TD, TLI)) + B.CreateMemCpy(Dst, Src, + ConstantInt::get(TD->getIntPtrType(*Context), Len), 1); + return Dst; + } +}; + +//===---------------------------------------===// +// 'stpcpy' Optimizations + +struct StpCpyOpt: public LibCallOptimization { + bool OptChkCall; // True if it's optimizing a __stpcpy_chk libcall. + + StpCpyOpt(bool c) : OptChkCall(c) {} + + virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) { + // Verify the "stpcpy" function prototype. + unsigned NumParams = OptChkCall ? 3 : 2; + FunctionType *FT = Callee->getFunctionType(); + if (FT->getNumParams() != NumParams || + FT->getReturnType() != FT->getParamType(0) || + FT->getParamType(0) != FT->getParamType(1) || + FT->getParamType(0) != B.getInt8PtrTy()) + return 0; + + // These optimizations require TargetData. + if (!TD) return 0; + + Value *Dst = CI->getArgOperand(0), *Src = CI->getArgOperand(1); + if (Dst == Src) { // stpcpy(x,x) -> x+strlen(x) + Value *StrLen = EmitStrLen(Src, B, TD, TLI); + return StrLen ? B.CreateInBoundsGEP(Dst, StrLen) : 0; + } + + // See if we can get the length of the input string. + uint64_t Len = GetStringLength(Src); + if (Len == 0) return 0; + + Value *LenV = ConstantInt::get(TD->getIntPtrType(*Context), Len); + Value *DstEnd = B.CreateGEP(Dst, + ConstantInt::get(TD->getIntPtrType(*Context), + 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. + if (!OptChkCall || !EmitMemCpyChk(Dst, Src, LenV, CI->getArgOperand(2), B, + TD, TLI)) + B.CreateMemCpy(Dst, Src, LenV, 1); + return DstEnd; + } +}; + +//===---------------------------------------===// +// 'strncpy' Optimizations + +struct StrNCpyOpt : public LibCallOptimization { + virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) { + 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()) + return 0; + + Value *Dst = CI->getArgOperand(0); + Value *Src = CI->getArgOperand(1); + Value *LenOp = CI->getArgOperand(2); + + // See if we can get the length of the input string. + uint64_t SrcLen = GetStringLength(Src); + if (SrcLen == 0) return 0; + --SrcLen; + + if (SrcLen == 0) { + // strncpy(x, "", y) -> memset(x, '\0', y, 1) + B.CreateMemSet(Dst, B.getInt8('\0'), LenOp, 1); + return Dst; + } + + uint64_t Len; + if (ConstantInt *LengthArg = dyn_cast<ConstantInt>(LenOp)) + Len = LengthArg->getZExtValue(); + else + return 0; + + if (Len == 0) return Dst; // strncpy(x, y, 0) -> x + + // These optimizations require TargetData. + if (!TD) return 0; + + // Let strncpy handle the zero padding + if (Len > SrcLen+1) return 0; + + // strncpy(x, s, c) -> memcpy(x, s, c, 1) [s and c are constant] + B.CreateMemCpy(Dst, Src, + ConstantInt::get(TD->getIntPtrType(*Context), Len), 1); + + return Dst; + } +}; + +//===---------------------------------------===// +// 'strlen' Optimizations + +struct StrLenOpt : public LibCallOptimization { + virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) { + FunctionType *FT = Callee->getFunctionType(); + if (FT->getNumParams() != 1 || + FT->getParamType(0) != B.getInt8PtrTy() || + !FT->getReturnType()->isIntegerTy()) + return 0; + + Value *Src = CI->getArgOperand(0); + + // Constant folding: strlen("xyz") -> 3 + if (uint64_t Len = GetStringLength(Src)) + return ConstantInt::get(CI->getType(), Len-1); + + // strlen(x) != 0 --> *x != 0 + // strlen(x) == 0 --> *x == 0 + if (IsOnlyUsedInZeroEqualityComparison(CI)) + return B.CreateZExt(B.CreateLoad(Src, "strlenfirst"), CI->getType()); + return 0; + } +}; + + +//===---------------------------------------===// +// 'strpbrk' Optimizations + +struct StrPBrkOpt : public LibCallOptimization { + virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) { + FunctionType *FT = Callee->getFunctionType(); + if (FT->getNumParams() != 2 || + FT->getParamType(0) != B.getInt8PtrTy() || + FT->getParamType(1) != FT->getParamType(0) || + FT->getReturnType() != FT->getParamType(0)) + return 0; + + StringRef S1, S2; + bool HasS1 = getConstantStringInfo(CI->getArgOperand(0), S1); + bool HasS2 = getConstantStringInfo(CI->getArgOperand(1), S2); + + // strpbrk(s, "") -> NULL + // strpbrk("", s) -> NULL + if ((HasS1 && S1.empty()) || (HasS2 && S2.empty())) + return Constant::getNullValue(CI->getType()); + + // Constant folding. + if (HasS1 && HasS2) { + size_t I = S1.find_first_of(S2); + if (I == std::string::npos) // No match. + return Constant::getNullValue(CI->getType()); + + return B.CreateGEP(CI->getArgOperand(0), B.getInt64(I), "strpbrk"); + } + + // strpbrk(s, "a") -> strchr(s, 'a') + if (TD && HasS2 && S2.size() == 1) + return EmitStrChr(CI->getArgOperand(0), S2[0], B, TD, TLI); + + return 0; + } +}; + +//===---------------------------------------===// +// 'strto*' Optimizations. This handles strtol, strtod, strtof, strtoul, etc. + +struct StrToOpt : public LibCallOptimization { + virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) { + FunctionType *FT = Callee->getFunctionType(); + if ((FT->getNumParams() != 2 && FT->getNumParams() != 3) || + !FT->getParamType(0)->isPointerTy() || + !FT->getParamType(1)->isPointerTy()) + return 0; + + Value *EndPtr = CI->getArgOperand(1); + if (isa<ConstantPointerNull>(EndPtr)) { + // With a null EndPtr, this function won't capture the main argument. + // It would be readonly too, except that it still may write to errno. + CI->addAttribute(1, Attribute::NoCapture); + } + + return 0; + } +}; + +//===---------------------------------------===// +// 'strspn' Optimizations + +struct StrSpnOpt : public LibCallOptimization { + virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) { + FunctionType *FT = Callee->getFunctionType(); + if (FT->getNumParams() != 2 || + FT->getParamType(0) != B.getInt8PtrTy() || + FT->getParamType(1) != FT->getParamType(0) || + !FT->getReturnType()->isIntegerTy()) + return 0; + + StringRef S1, S2; + bool HasS1 = getConstantStringInfo(CI->getArgOperand(0), S1); + bool HasS2 = getConstantStringInfo(CI->getArgOperand(1), S2); + + // strspn(s, "") -> 0 + // strspn("", s) -> 0 + if ((HasS1 && S1.empty()) || (HasS2 && S2.empty())) + return Constant::getNullValue(CI->getType()); + + // Constant folding. + if (HasS1 && HasS2) { + size_t Pos = S1.find_first_not_of(S2); + if (Pos == StringRef::npos) Pos = S1.size(); + return ConstantInt::get(CI->getType(), Pos); + } + + return 0; + } +}; + +//===---------------------------------------===// +// 'strcspn' Optimizations + +struct StrCSpnOpt : public LibCallOptimization { + virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) { + FunctionType *FT = Callee->getFunctionType(); + if (FT->getNumParams() != 2 || + FT->getParamType(0) != B.getInt8PtrTy() || + FT->getParamType(1) != FT->getParamType(0) || + !FT->getReturnType()->isIntegerTy()) + return 0; + + StringRef S1, S2; + bool HasS1 = getConstantStringInfo(CI->getArgOperand(0), S1); + bool HasS2 = getConstantStringInfo(CI->getArgOperand(1), S2); + + // strcspn("", s) -> 0 + if (HasS1 && S1.empty()) + return Constant::getNullValue(CI->getType()); + + // Constant folding. + if (HasS1 && HasS2) { + size_t Pos = S1.find_first_of(S2); + if (Pos == StringRef::npos) Pos = S1.size(); + return ConstantInt::get(CI->getType(), Pos); + } + + // strcspn(s, "") -> strlen(s) + if (TD && HasS2 && S2.empty()) + return EmitStrLen(CI->getArgOperand(0), B, TD, TLI); + + return 0; + } +}; + +//===---------------------------------------===// +// 'strstr' Optimizations + +struct StrStrOpt : public LibCallOptimization { + virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) { + FunctionType *FT = Callee->getFunctionType(); + if (FT->getNumParams() != 2 || + !FT->getParamType(0)->isPointerTy() || + !FT->getParamType(1)->isPointerTy() || + !FT->getReturnType()->isPointerTy()) + return 0; + + // fold strstr(x, x) -> x. + if (CI->getArgOperand(0) == CI->getArgOperand(1)) + return B.CreateBitCast(CI->getArgOperand(0), CI->getType()); + + // fold strstr(a, b) == a -> strncmp(a, b, strlen(b)) == 0 + if (TD && IsOnlyUsedInEqualityComparison(CI, CI->getArgOperand(0))) { + Value *StrLen = EmitStrLen(CI->getArgOperand(1), B, TD, TLI); + if (!StrLen) + return 0; + Value *StrNCmp = EmitStrNCmp(CI->getArgOperand(0), CI->getArgOperand(1), + StrLen, B, TD, TLI); + if (!StrNCmp) + return 0; + for (Value::use_iterator UI = CI->use_begin(), UE = CI->use_end(); + UI != UE; ) { + ICmpInst *Old = cast<ICmpInst>(*UI++); + Value *Cmp = B.CreateICmp(Old->getPredicate(), StrNCmp, + ConstantInt::getNullValue(StrNCmp->getType()), + "cmp"); + Old->replaceAllUsesWith(Cmp); + Old->eraseFromParent(); + } + return CI; + } + + // See if either input string is a constant string. + StringRef SearchStr, ToFindStr; + bool HasStr1 = getConstantStringInfo(CI->getArgOperand(0), SearchStr); + bool HasStr2 = getConstantStringInfo(CI->getArgOperand(1), ToFindStr); + + // fold strstr(x, "") -> x. + if (HasStr2 && ToFindStr.empty()) + return B.CreateBitCast(CI->getArgOperand(0), CI->getType()); + + // If both strings are known, constant fold it. + if (HasStr1 && HasStr2) { + std::string::size_type Offset = SearchStr.find(ToFindStr); + + if (Offset == StringRef::npos) // strstr("foo", "bar") -> null + return Constant::getNullValue(CI->getType()); + + // strstr("abcd", "bc") -> gep((char*)"abcd", 1) + Value *Result = CastToCStr(CI->getArgOperand(0), B); + Result = B.CreateConstInBoundsGEP1_64(Result, Offset, "strstr"); + return B.CreateBitCast(Result, CI->getType()); + } + + // fold strstr(x, "y") -> strchr(x, 'y'). + if (HasStr2 && ToFindStr.size() == 1) { + Value *StrChr= EmitStrChr(CI->getArgOperand(0), ToFindStr[0], B, TD, TLI); + return StrChr ? B.CreateBitCast(StrChr, CI->getType()) : 0; + } + return 0; + } +}; + + +//===---------------------------------------===// +// 'memcmp' Optimizations + +struct MemCmpOpt : public LibCallOptimization { + virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) { + FunctionType *FT = Callee->getFunctionType(); + if (FT->getNumParams() != 3 || !FT->getParamType(0)->isPointerTy() || + !FT->getParamType(1)->isPointerTy() || + !FT->getReturnType()->isIntegerTy(32)) + return 0; + + Value *LHS = CI->getArgOperand(0), *RHS = CI->getArgOperand(1); + + if (LHS == RHS) // memcmp(s,s,x) -> 0 + return Constant::getNullValue(CI->getType()); + + // Make sure we have a constant length. + ConstantInt *LenC = dyn_cast<ConstantInt>(CI->getArgOperand(2)); + if (!LenC) return 0; + uint64_t Len = LenC->getZExtValue(); + + if (Len == 0) // memcmp(s1,s2,0) -> 0 + return Constant::getNullValue(CI->getType()); + + // memcmp(S1,S2,1) -> *(unsigned char*)LHS - *(unsigned char*)RHS + if (Len == 1) { + Value *LHSV = B.CreateZExt(B.CreateLoad(CastToCStr(LHS, B), "lhsc"), + CI->getType(), "lhsv"); + Value *RHSV = B.CreateZExt(B.CreateLoad(CastToCStr(RHS, B), "rhsc"), + CI->getType(), "rhsv"); + return B.CreateSub(LHSV, RHSV, "chardiff"); + } + + // Constant folding: memcmp(x, y, l) -> cnst (all arguments are constant) + StringRef LHSStr, RHSStr; + if (getConstantStringInfo(LHS, LHSStr) && + getConstantStringInfo(RHS, RHSStr)) { + // Make sure we're not reading out-of-bounds memory. + if (Len > LHSStr.size() || Len > RHSStr.size()) + return 0; + uint64_t Ret = memcmp(LHSStr.data(), RHSStr.data(), Len); + return ConstantInt::get(CI->getType(), Ret); + } + + return 0; + } +}; + +//===---------------------------------------===// +// 'memcpy' Optimizations + +struct MemCpyOpt : public LibCallOptimization { + virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) { + // These optimizations require TargetData. + if (!TD) return 0; + + FunctionType *FT = Callee->getFunctionType(); + if (FT->getNumParams() != 3 || FT->getReturnType() != FT->getParamType(0) || + !FT->getParamType(0)->isPointerTy() || + !FT->getParamType(1)->isPointerTy() || + FT->getParamType(2) != TD->getIntPtrType(*Context)) + return 0; + + // memcpy(x, y, n) -> llvm.memcpy(x, y, n, 1) + B.CreateMemCpy(CI->getArgOperand(0), CI->getArgOperand(1), + CI->getArgOperand(2), 1); + return CI->getArgOperand(0); + } +}; + +//===---------------------------------------===// +// 'memmove' Optimizations + +struct MemMoveOpt : public LibCallOptimization { + virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) { + // These optimizations require TargetData. + if (!TD) return 0; + + FunctionType *FT = Callee->getFunctionType(); + if (FT->getNumParams() != 3 || FT->getReturnType() != FT->getParamType(0) || + !FT->getParamType(0)->isPointerTy() || + !FT->getParamType(1)->isPointerTy() || + FT->getParamType(2) != TD->getIntPtrType(*Context)) + return 0; + + // memmove(x, y, n) -> llvm.memmove(x, y, n, 1) + B.CreateMemMove(CI->getArgOperand(0), CI->getArgOperand(1), + CI->getArgOperand(2), 1); + return CI->getArgOperand(0); + } +}; + +//===---------------------------------------===// +// 'memset' Optimizations + +struct MemSetOpt : public LibCallOptimization { + virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) { + // These optimizations require TargetData. + if (!TD) return 0; + + FunctionType *FT = Callee->getFunctionType(); + if (FT->getNumParams() != 3 || FT->getReturnType() != FT->getParamType(0) || + !FT->getParamType(0)->isPointerTy() || + !FT->getParamType(1)->isIntegerTy() || + FT->getParamType(2) != TD->getIntPtrType(*Context)) + return 0; + + // memset(p, v, n) -> llvm.memset(p, v, n, 1) + Value *Val = B.CreateIntCast(CI->getArgOperand(1), B.getInt8Ty(), false); + B.CreateMemSet(CI->getArgOperand(0), Val, CI->getArgOperand(2), 1); + return CI->getArgOperand(0); + } +}; + +//===----------------------------------------------------------------------===// +// Math Library Optimizations +//===----------------------------------------------------------------------===// + +//===---------------------------------------===// +// 'cos*' Optimizations + +struct CosOpt : public LibCallOptimization { + virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) { + FunctionType *FT = Callee->getFunctionType(); + // Just make sure this has 1 argument of FP type, which matches the + // result type. + if (FT->getNumParams() != 1 || FT->getReturnType() != FT->getParamType(0) || + !FT->getParamType(0)->isFloatingPointTy()) + return 0; + + // cos(-x) -> cos(x) + Value *Op1 = CI->getArgOperand(0); + if (BinaryOperator::isFNeg(Op1)) { + BinaryOperator *BinExpr = cast<BinaryOperator>(Op1); + return B.CreateCall(Callee, BinExpr->getOperand(1), "cos"); + } + return 0; + } +}; + +//===---------------------------------------===// +// 'pow*' Optimizations + +struct PowOpt : public LibCallOptimization { + virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) { + FunctionType *FT = Callee->getFunctionType(); + // Just make sure this has 2 arguments of the same FP type, which match the + // result type. + if (FT->getNumParams() != 2 || FT->getReturnType() != FT->getParamType(0) || + FT->getParamType(0) != FT->getParamType(1) || + !FT->getParamType(0)->isFloatingPointTy()) + return 0; + + Value *Op1 = CI->getArgOperand(0), *Op2 = CI->getArgOperand(1); + if (ConstantFP *Op1C = dyn_cast<ConstantFP>(Op1)) { + if (Op1C->isExactlyValue(1.0)) // pow(1.0, x) -> 1.0 + return Op1C; + if (Op1C->isExactlyValue(2.0)) // pow(2.0, x) -> exp2(x) + return EmitUnaryFloatFnCall(Op2, "exp2", B, Callee->getAttributes()); + } + + ConstantFP *Op2C = dyn_cast<ConstantFP>(Op2); + if (Op2C == 0) return 0; + + if (Op2C->getValueAPF().isZero()) // pow(x, 0.0) -> 1.0 + return ConstantFP::get(CI->getType(), 1.0); + + if (Op2C->isExactlyValue(0.5)) { + // Expand pow(x, 0.5) to (x == -infinity ? +infinity : fabs(sqrt(x))). + // This is faster than calling pow, and still handles negative zero + // and negative infinity correctly. + // TODO: In fast-math mode, this could be just sqrt(x). + // TODO: In finite-only mode, this could be just fabs(sqrt(x)). + Value *Inf = ConstantFP::getInfinity(CI->getType()); + Value *NegInf = ConstantFP::getInfinity(CI->getType(), true); + Value *Sqrt = EmitUnaryFloatFnCall(Op1, "sqrt", B, + Callee->getAttributes()); + Value *FAbs = EmitUnaryFloatFnCall(Sqrt, "fabs", B, + Callee->getAttributes()); + Value *FCmp = B.CreateFCmpOEQ(Op1, NegInf); + Value *Sel = B.CreateSelect(FCmp, Inf, FAbs); + return Sel; + } + + if (Op2C->isExactlyValue(1.0)) // pow(x, 1.0) -> x + return Op1; + if (Op2C->isExactlyValue(2.0)) // pow(x, 2.0) -> x*x + return B.CreateFMul(Op1, Op1, "pow2"); + if (Op2C->isExactlyValue(-1.0)) // pow(x, -1.0) -> 1.0/x + return B.CreateFDiv(ConstantFP::get(CI->getType(), 1.0), + Op1, "powrecip"); + return 0; + } +}; + +//===---------------------------------------===// +// 'exp2' Optimizations + +struct Exp2Opt : public LibCallOptimization { + virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) { + FunctionType *FT = Callee->getFunctionType(); + // Just make sure this has 1 argument of FP type, which matches the + // result type. + if (FT->getNumParams() != 1 || FT->getReturnType() != FT->getParamType(0) || + !FT->getParamType(0)->isFloatingPointTy()) + return 0; + + Value *Op = CI->getArgOperand(0); + // Turn exp2(sitofp(x)) -> ldexp(1.0, sext(x)) if sizeof(x) <= 32 + // Turn exp2(uitofp(x)) -> ldexp(1.0, zext(x)) if sizeof(x) < 32 + Value *LdExpArg = 0; + if (SIToFPInst *OpC = dyn_cast<SIToFPInst>(Op)) { + if (OpC->getOperand(0)->getType()->getPrimitiveSizeInBits() <= 32) + LdExpArg = B.CreateSExt(OpC->getOperand(0), B.getInt32Ty()); + } else if (UIToFPInst *OpC = dyn_cast<UIToFPInst>(Op)) { + if (OpC->getOperand(0)->getType()->getPrimitiveSizeInBits() < 32) + LdExpArg = B.CreateZExt(OpC->getOperand(0), B.getInt32Ty()); + } + + if (LdExpArg) { + const char *Name; + if (Op->getType()->isFloatTy()) + Name = "ldexpf"; + else if (Op->getType()->isDoubleTy()) + Name = "ldexp"; + else + Name = "ldexpl"; + + Constant *One = ConstantFP::get(*Context, APFloat(1.0f)); + if (!Op->getType()->isFloatTy()) + One = ConstantExpr::getFPExtend(One, Op->getType()); + + Module *M = Caller->getParent(); + Value *Callee = M->getOrInsertFunction(Name, Op->getType(), + Op->getType(), + B.getInt32Ty(), NULL); + CallInst *CI = B.CreateCall2(Callee, One, LdExpArg); + if (const Function *F = dyn_cast<Function>(Callee->stripPointerCasts())) + CI->setCallingConv(F->getCallingConv()); + + return CI; + } + return 0; + } +}; + +//===---------------------------------------===// +// Double -> Float Shrinking Optimizations for Unary Functions like 'floor' + +struct UnaryDoubleFPOpt : public LibCallOptimization { + virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) { + FunctionType *FT = Callee->getFunctionType(); + if (FT->getNumParams() != 1 || !FT->getReturnType()->isDoubleTy() || + !FT->getParamType(0)->isDoubleTy()) + return 0; + + // If this is something like 'floor((double)floatval)', convert to floorf. + FPExtInst *Cast = dyn_cast<FPExtInst>(CI->getArgOperand(0)); + if (Cast == 0 || !Cast->getOperand(0)->getType()->isFloatTy()) + return 0; + + // floor((double)floatval) -> (double)floorf(floatval) + Value *V = Cast->getOperand(0); + V = EmitUnaryFloatFnCall(V, Callee->getName(), B, Callee->getAttributes()); + return B.CreateFPExt(V, B.getDoubleTy()); + } +}; + +//===----------------------------------------------------------------------===// +// Integer Optimizations +//===----------------------------------------------------------------------===// + +//===---------------------------------------===// +// 'ffs*' Optimizations + +struct FFSOpt : public LibCallOptimization { + virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) { + FunctionType *FT = Callee->getFunctionType(); + // Just make sure this has 2 arguments of the same FP type, which match the + // result type. + if (FT->getNumParams() != 1 || + !FT->getReturnType()->isIntegerTy(32) || + !FT->getParamType(0)->isIntegerTy()) + return 0; + + Value *Op = CI->getArgOperand(0); + + // Constant fold. + if (ConstantInt *CI = dyn_cast<ConstantInt>(Op)) { + if (CI->getValue() == 0) // ffs(0) -> 0. + return Constant::getNullValue(CI->getType()); + // ffs(c) -> cttz(c)+1 + return B.getInt32(CI->getValue().countTrailingZeros() + 1); + } + + // ffs(x) -> x != 0 ? (i32)llvm.cttz(x)+1 : 0 + Type *ArgType = Op->getType(); + Value *F = Intrinsic::getDeclaration(Callee->getParent(), + Intrinsic::cttz, ArgType); + Value *V = B.CreateCall2(F, Op, B.getFalse(), "cttz"); + V = B.CreateAdd(V, ConstantInt::get(V->getType(), 1)); + V = B.CreateIntCast(V, B.getInt32Ty(), false); + + Value *Cond = B.CreateICmpNE(Op, Constant::getNullValue(ArgType)); + return B.CreateSelect(Cond, V, B.getInt32(0)); + } +}; + +//===---------------------------------------===// +// 'isdigit' Optimizations + +struct IsDigitOpt : public LibCallOptimization { + virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) { + FunctionType *FT = Callee->getFunctionType(); + // We require integer(i32) + if (FT->getNumParams() != 1 || !FT->getReturnType()->isIntegerTy() || + !FT->getParamType(0)->isIntegerTy(32)) + return 0; + + // isdigit(c) -> (c-'0') <u 10 + Value *Op = CI->getArgOperand(0); + Op = B.CreateSub(Op, B.getInt32('0'), "isdigittmp"); + Op = B.CreateICmpULT(Op, B.getInt32(10), "isdigit"); + return B.CreateZExt(Op, CI->getType()); + } +}; + +//===---------------------------------------===// +// 'isascii' Optimizations + +struct IsAsciiOpt : public LibCallOptimization { + virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) { + FunctionType *FT = Callee->getFunctionType(); + // We require integer(i32) + if (FT->getNumParams() != 1 || !FT->getReturnType()->isIntegerTy() || + !FT->getParamType(0)->isIntegerTy(32)) + return 0; + + // isascii(c) -> c <u 128 + Value *Op = CI->getArgOperand(0); + Op = B.CreateICmpULT(Op, B.getInt32(128), "isascii"); + return B.CreateZExt(Op, CI->getType()); + } +}; + +//===---------------------------------------===// +// 'abs', 'labs', 'llabs' Optimizations + +struct AbsOpt : public LibCallOptimization { + virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) { + FunctionType *FT = Callee->getFunctionType(); + // We require integer(integer) where the types agree. + if (FT->getNumParams() != 1 || !FT->getReturnType()->isIntegerTy() || + FT->getParamType(0) != FT->getReturnType()) + return 0; + + // abs(x) -> x >s -1 ? x : -x + Value *Op = CI->getArgOperand(0); + Value *Pos = B.CreateICmpSGT(Op, Constant::getAllOnesValue(Op->getType()), + "ispos"); + Value *Neg = B.CreateNeg(Op, "neg"); + return B.CreateSelect(Pos, Op, Neg); + } +}; + + +//===---------------------------------------===// +// 'toascii' Optimizations + +struct ToAsciiOpt : public LibCallOptimization { + virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) { + FunctionType *FT = Callee->getFunctionType(); + // We require i32(i32) + if (FT->getNumParams() != 1 || FT->getReturnType() != FT->getParamType(0) || + !FT->getParamType(0)->isIntegerTy(32)) + return 0; + + // isascii(c) -> c & 0x7f + return B.CreateAnd(CI->getArgOperand(0), + ConstantInt::get(CI->getType(),0x7F)); + } +}; + +//===----------------------------------------------------------------------===// +// Formatting and IO Optimizations +//===----------------------------------------------------------------------===// + +//===---------------------------------------===// +// 'printf' Optimizations + +struct PrintFOpt : public LibCallOptimization { + Value *OptimizeFixedFormatString(Function *Callee, CallInst *CI, + IRBuilder<> &B) { + // Check for a fixed format string. + StringRef FormatStr; + if (!getConstantStringInfo(CI->getArgOperand(0), FormatStr)) + return 0; + + // Empty format string -> noop. + if (FormatStr.empty()) // Tolerate printf's declared void. + return CI->use_empty() ? (Value*)CI : + ConstantInt::get(CI->getType(), 0); + + // Do not do any of the following transformations if the printf return value + // is used, in general the printf return value is not compatible with either + // putchar() or puts(). + if (!CI->use_empty()) + return 0; + + // printf("x") -> putchar('x'), even for '%'. + if (FormatStr.size() == 1) { + Value *Res = EmitPutChar(B.getInt32(FormatStr[0]), B, TD, TLI); + if (CI->use_empty() || !Res) return Res; + return B.CreateIntCast(Res, CI->getType(), true); + } + + // printf("foo\n") --> puts("foo") + if (FormatStr[FormatStr.size()-1] == '\n' && + FormatStr.find('%') == std::string::npos) { // no format characters. + // Create a string literal with no \n on it. We expect the constant merge + // 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, TD, TLI); + return (CI->use_empty() || !NewCI) ? + NewCI : + ConstantInt::get(CI->getType(), FormatStr.size()+1); + } + + // Optimize specific format strings. + // printf("%c", chr) --> putchar(chr) + if (FormatStr == "%c" && CI->getNumArgOperands() > 1 && + CI->getArgOperand(1)->getType()->isIntegerTy()) { + Value *Res = EmitPutChar(CI->getArgOperand(1), B, TD, TLI); + + if (CI->use_empty() || !Res) return Res; + return B.CreateIntCast(Res, CI->getType(), true); + } + + // printf("%s\n", str) --> puts(str) + if (FormatStr == "%s\n" && CI->getNumArgOperands() > 1 && + CI->getArgOperand(1)->getType()->isPointerTy()) { + return EmitPutS(CI->getArgOperand(1), B, TD, TLI); + } + return 0; + } + + virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) { + // Require one fixed pointer argument and an integer/void result. + FunctionType *FT = Callee->getFunctionType(); + if (FT->getNumParams() < 1 || !FT->getParamType(0)->isPointerTy() || + !(FT->getReturnType()->isIntegerTy() || + FT->getReturnType()->isVoidTy())) + return 0; + + if (Value *V = OptimizeFixedFormatString(Callee, CI, B)) { + return V; + } + + // printf(format, ...) -> iprintf(format, ...) if no floating point + // arguments. + if (TLI->has(LibFunc::iprintf) && !CallHasFloatingPointArgument(CI)) { + Module *M = B.GetInsertBlock()->getParent()->getParent(); + Constant *IPrintFFn = + M->getOrInsertFunction("iprintf", FT, Callee->getAttributes()); + CallInst *New = cast<CallInst>(CI->clone()); + New->setCalledFunction(IPrintFFn); + B.Insert(New); + return New; + } + return 0; + } +}; + +//===---------------------------------------===// +// 'sprintf' Optimizations + +struct SPrintFOpt : public LibCallOptimization { + Value *OptimizeFixedFormatString(Function *Callee, CallInst *CI, + IRBuilder<> &B) { + // Check for a fixed format string. + StringRef FormatStr; + if (!getConstantStringInfo(CI->getArgOperand(1), FormatStr)) + return 0; + + // If we just have a format string (nothing else crazy) transform it. + if (CI->getNumArgOperands() == 2) { + // Make sure there's no % in the constant array. We could try to handle + // %% -> % in the future if we cared. + for (unsigned i = 0, e = FormatStr.size(); i != e; ++i) + if (FormatStr[i] == '%') + return 0; // we found a format specifier, bail out. + + // These optimizations require TargetData. + if (!TD) return 0; + + // sprintf(str, fmt) -> llvm.memcpy(str, fmt, strlen(fmt)+1, 1) + B.CreateMemCpy(CI->getArgOperand(0), CI->getArgOperand(1), + ConstantInt::get(TD->getIntPtrType(*Context), // Copy the + FormatStr.size() + 1), 1); // nul byte. + return ConstantInt::get(CI->getType(), FormatStr.size()); + } + + // The remaining optimizations require the format string to be "%s" or "%c" + // and have an extra operand. + if (FormatStr.size() != 2 || FormatStr[0] != '%' || + CI->getNumArgOperands() < 3) + return 0; + + // Decode the second character of the format string. + if (FormatStr[1] == 'c') { + // sprintf(dst, "%c", chr) --> *(i8*)dst = chr; *((i8*)dst+1) = 0 + if (!CI->getArgOperand(2)->getType()->isIntegerTy()) return 0; + 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"); + B.CreateStore(B.getInt8(0), Ptr); + + return ConstantInt::get(CI->getType(), 1); + } + + if (FormatStr[1] == 's') { + // These optimizations require TargetData. + if (!TD) return 0; + + // sprintf(dest, "%s", str) -> llvm.memcpy(dest, str, strlen(str)+1, 1) + if (!CI->getArgOperand(2)->getType()->isPointerTy()) return 0; + + Value *Len = EmitStrLen(CI->getArgOperand(2), B, TD, TLI); + if (!Len) + return 0; + Value *IncLen = B.CreateAdd(Len, + ConstantInt::get(Len->getType(), 1), + "leninc"); + B.CreateMemCpy(CI->getArgOperand(0), CI->getArgOperand(2), IncLen, 1); + + // The sprintf result is the unincremented number of bytes in the string. + return B.CreateIntCast(Len, CI->getType(), false); + } + return 0; + } + + virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) { + // Require two fixed pointer arguments and an integer result. + FunctionType *FT = Callee->getFunctionType(); + if (FT->getNumParams() != 2 || !FT->getParamType(0)->isPointerTy() || + !FT->getParamType(1)->isPointerTy() || + !FT->getReturnType()->isIntegerTy()) + return 0; + + if (Value *V = OptimizeFixedFormatString(Callee, CI, B)) { + return V; + } + + // sprintf(str, format, ...) -> siprintf(str, format, ...) if no floating + // point arguments. + if (TLI->has(LibFunc::siprintf) && !CallHasFloatingPointArgument(CI)) { + Module *M = B.GetInsertBlock()->getParent()->getParent(); + Constant *SIPrintFFn = + M->getOrInsertFunction("siprintf", FT, Callee->getAttributes()); + CallInst *New = cast<CallInst>(CI->clone()); + New->setCalledFunction(SIPrintFFn); + B.Insert(New); + return New; + } + return 0; + } +}; + +//===---------------------------------------===// +// 'fwrite' Optimizations + +struct FWriteOpt : public LibCallOptimization { + virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) { + // Require a pointer, an integer, an integer, a pointer, returning integer. + FunctionType *FT = Callee->getFunctionType(); + if (FT->getNumParams() != 4 || !FT->getParamType(0)->isPointerTy() || + !FT->getParamType(1)->isIntegerTy() || + !FT->getParamType(2)->isIntegerTy() || + !FT->getParamType(3)->isPointerTy() || + !FT->getReturnType()->isIntegerTy()) + return 0; + + // Get the element size and count. + ConstantInt *SizeC = dyn_cast<ConstantInt>(CI->getArgOperand(1)); + ConstantInt *CountC = dyn_cast<ConstantInt>(CI->getArgOperand(2)); + if (!SizeC || !CountC) return 0; + uint64_t Bytes = SizeC->getZExtValue()*CountC->getZExtValue(); + + // If this is writing zero records, remove the call (it's a noop). + if (Bytes == 0) + return ConstantInt::get(CI->getType(), 0); + + // If this is writing one byte, turn it into fputc. + // 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, TD, TLI); + return NewCI ? ConstantInt::get(CI->getType(), 1) : 0; + } + + return 0; + } +}; + +//===---------------------------------------===// +// 'fputs' Optimizations + +struct FPutsOpt : public LibCallOptimization { + virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) { + // These optimizations require TargetData. + if (!TD) return 0; + + // 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() || + !FT->getParamType(1)->isPointerTy() || + !CI->use_empty()) + return 0; + + // fputs(s,F) --> fwrite(s,1,strlen(s),F) + uint64_t Len = GetStringLength(CI->getArgOperand(0)); + if (!Len) return 0; + // Known to have no uses (see above). + return EmitFWrite(CI->getArgOperand(0), + ConstantInt::get(TD->getIntPtrType(*Context), Len-1), + CI->getArgOperand(1), B, TD, TLI); + } +}; + +//===---------------------------------------===// +// 'fprintf' Optimizations + +struct FPrintFOpt : public LibCallOptimization { + Value *OptimizeFixedFormatString(Function *Callee, CallInst *CI, + IRBuilder<> &B) { + // All the optimizations depend on the format string. + StringRef FormatStr; + if (!getConstantStringInfo(CI->getArgOperand(1), FormatStr)) + return 0; + + // fprintf(F, "foo") --> fwrite("foo", 3, 1, F) + if (CI->getNumArgOperands() == 2) { + for (unsigned i = 0, e = FormatStr.size(); i != e; ++i) + if (FormatStr[i] == '%') // Could handle %% -> % if we cared. + return 0; // We found a format specifier. + + // These optimizations require TargetData. + if (!TD) return 0; + + Value *NewCI = EmitFWrite(CI->getArgOperand(1), + ConstantInt::get(TD->getIntPtrType(*Context), + FormatStr.size()), + CI->getArgOperand(0), B, TD, TLI); + return NewCI ? ConstantInt::get(CI->getType(), FormatStr.size()) : 0; + } + + // The remaining optimizations require the format string to be "%s" or "%c" + // and have an extra operand. + if (FormatStr.size() != 2 || FormatStr[0] != '%' || + CI->getNumArgOperands() < 3) + return 0; + + // Decode the second character of the format string. + if (FormatStr[1] == 'c') { + // fprintf(F, "%c", chr) --> fputc(chr, F) + if (!CI->getArgOperand(2)->getType()->isIntegerTy()) return 0; + Value *NewCI = EmitFPutC(CI->getArgOperand(2), CI->getArgOperand(0), B, + TD, TLI); + return NewCI ? ConstantInt::get(CI->getType(), 1) : 0; + } + + if (FormatStr[1] == 's') { + // fprintf(F, "%s", str) --> fputs(str, F) + if (!CI->getArgOperand(2)->getType()->isPointerTy() || !CI->use_empty()) + return 0; + return EmitFPutS(CI->getArgOperand(2), CI->getArgOperand(0), B, TD, TLI); + } + return 0; + } + + virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) { + // Require two fixed paramters as pointers and integer result. + FunctionType *FT = Callee->getFunctionType(); + if (FT->getNumParams() != 2 || !FT->getParamType(0)->isPointerTy() || + !FT->getParamType(1)->isPointerTy() || + !FT->getReturnType()->isIntegerTy()) + return 0; + + if (Value *V = OptimizeFixedFormatString(Callee, CI, B)) { + return V; + } + + // fprintf(stream, format, ...) -> fiprintf(stream, format, ...) if no + // floating point arguments. + if (TLI->has(LibFunc::fiprintf) && !CallHasFloatingPointArgument(CI)) { + Module *M = B.GetInsertBlock()->getParent()->getParent(); + Constant *FIPrintFFn = + M->getOrInsertFunction("fiprintf", FT, Callee->getAttributes()); + CallInst *New = cast<CallInst>(CI->clone()); + New->setCalledFunction(FIPrintFFn); + B.Insert(New); + return New; + } + return 0; + } +}; + +//===---------------------------------------===// +// 'puts' Optimizations + +struct PutsOpt : public LibCallOptimization { + virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) { + // Require one fixed pointer argument and an integer/void result. + FunctionType *FT = Callee->getFunctionType(); + if (FT->getNumParams() < 1 || !FT->getParamType(0)->isPointerTy() || + !(FT->getReturnType()->isIntegerTy() || + FT->getReturnType()->isVoidTy())) + return 0; + + // Check for a constant string. + StringRef Str; + if (!getConstantStringInfo(CI->getArgOperand(0), Str)) + return 0; + + if (Str.empty() && CI->use_empty()) { + // puts("") -> putchar('\n') + Value *Res = EmitPutChar(B.getInt32('\n'), B, TD, TLI); + if (CI->use_empty() || !Res) return Res; + return B.CreateIntCast(Res, CI->getType(), true); + } + + return 0; + } +}; + +} // end anonymous namespace. + +//===----------------------------------------------------------------------===// +// SimplifyLibCalls Pass Implementation +//===----------------------------------------------------------------------===// + +namespace { + /// This pass optimizes well known library functions from libc and libm. + /// + class SimplifyLibCalls : public FunctionPass { + TargetLibraryInfo *TLI; + + StringMap<LibCallOptimization*> Optimizations; + // String and Memory LibCall Optimizations + StrCatOpt StrCat; StrNCatOpt StrNCat; StrChrOpt StrChr; StrRChrOpt StrRChr; + StrCmpOpt StrCmp; StrNCmpOpt StrNCmp; + StrCpyOpt StrCpy; StrCpyOpt StrCpyChk; + StpCpyOpt StpCpy; StpCpyOpt StpCpyChk; + StrNCpyOpt StrNCpy; + StrLenOpt StrLen; StrPBrkOpt StrPBrk; + StrToOpt StrTo; StrSpnOpt StrSpn; StrCSpnOpt StrCSpn; StrStrOpt StrStr; + MemCmpOpt MemCmp; MemCpyOpt MemCpy; MemMoveOpt MemMove; MemSetOpt MemSet; + // Math Library Optimizations + CosOpt Cos; PowOpt Pow; Exp2Opt Exp2; UnaryDoubleFPOpt UnaryDoubleFP; + // Integer Optimizations + FFSOpt FFS; AbsOpt Abs; IsDigitOpt IsDigit; IsAsciiOpt IsAscii; + ToAsciiOpt ToAscii; + // Formatting and IO Optimizations + SPrintFOpt SPrintF; PrintFOpt PrintF; + FWriteOpt FWrite; FPutsOpt FPuts; FPrintFOpt FPrintF; + PutsOpt Puts; + + bool Modified; // This is only used by doInitialization. + public: + static char ID; // Pass identification + SimplifyLibCalls() : FunctionPass(ID), StrCpy(false), StrCpyChk(true), + StpCpy(false), StpCpyChk(true) { + initializeSimplifyLibCallsPass(*PassRegistry::getPassRegistry()); + } + void AddOpt(LibFunc::Func F, LibCallOptimization* Opt); + void InitOptimizations(); + bool runOnFunction(Function &F); + + void setDoesNotAccessMemory(Function &F); + void setOnlyReadsMemory(Function &F); + void setDoesNotThrow(Function &F); + void setDoesNotCapture(Function &F, unsigned n); + void setDoesNotAlias(Function &F, unsigned n); + bool doInitialization(Module &M); + + void inferPrototypeAttributes(Function &F); + virtual void getAnalysisUsage(AnalysisUsage &AU) const { + AU.addRequired<TargetLibraryInfo>(); + } + }; +} // end anonymous namespace. + +char SimplifyLibCalls::ID = 0; + +INITIALIZE_PASS_BEGIN(SimplifyLibCalls, "simplify-libcalls", + "Simplify well-known library calls", false, false) +INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfo) +INITIALIZE_PASS_END(SimplifyLibCalls, "simplify-libcalls", + "Simplify well-known library calls", false, false) + +// Public interface to the Simplify LibCalls pass. +FunctionPass *llvm::createSimplifyLibCallsPass() { + return new SimplifyLibCalls(); +} + +void SimplifyLibCalls::AddOpt(LibFunc::Func F, LibCallOptimization* Opt) { + if (TLI->has(F)) + Optimizations[TLI->getName(F)] = Opt; +} + +/// Optimizations - Populate the Optimizations map with all the optimizations +/// we know. +void SimplifyLibCalls::InitOptimizations() { + // String and Memory LibCall Optimizations + Optimizations["strcat"] = &StrCat; + Optimizations["strncat"] = &StrNCat; + Optimizations["strchr"] = &StrChr; + Optimizations["strrchr"] = &StrRChr; + Optimizations["strcmp"] = &StrCmp; + Optimizations["strncmp"] = &StrNCmp; + Optimizations["strcpy"] = &StrCpy; + Optimizations["strncpy"] = &StrNCpy; + Optimizations["stpcpy"] = &StpCpy; + Optimizations["strlen"] = &StrLen; + Optimizations["strpbrk"] = &StrPBrk; + Optimizations["strtol"] = &StrTo; + Optimizations["strtod"] = &StrTo; + Optimizations["strtof"] = &StrTo; + Optimizations["strtoul"] = &StrTo; + Optimizations["strtoll"] = &StrTo; + Optimizations["strtold"] = &StrTo; + Optimizations["strtoull"] = &StrTo; + Optimizations["strspn"] = &StrSpn; + Optimizations["strcspn"] = &StrCSpn; + Optimizations["strstr"] = &StrStr; + Optimizations["memcmp"] = &MemCmp; + AddOpt(LibFunc::memcpy, &MemCpy); + Optimizations["memmove"] = &MemMove; + AddOpt(LibFunc::memset, &MemSet); + + // _chk variants of String and Memory LibCall Optimizations. + Optimizations["__strcpy_chk"] = &StrCpyChk; + Optimizations["__stpcpy_chk"] = &StpCpyChk; + + // Math Library Optimizations + Optimizations["cosf"] = &Cos; + Optimizations["cos"] = &Cos; + Optimizations["cosl"] = &Cos; + Optimizations["powf"] = &Pow; + Optimizations["pow"] = &Pow; + Optimizations["powl"] = &Pow; + Optimizations["llvm.pow.f32"] = &Pow; + Optimizations["llvm.pow.f64"] = &Pow; + Optimizations["llvm.pow.f80"] = &Pow; + Optimizations["llvm.pow.f128"] = &Pow; + Optimizations["llvm.pow.ppcf128"] = &Pow; + Optimizations["exp2l"] = &Exp2; + Optimizations["exp2"] = &Exp2; + Optimizations["exp2f"] = &Exp2; + Optimizations["llvm.exp2.ppcf128"] = &Exp2; + Optimizations["llvm.exp2.f128"] = &Exp2; + Optimizations["llvm.exp2.f80"] = &Exp2; + Optimizations["llvm.exp2.f64"] = &Exp2; + Optimizations["llvm.exp2.f32"] = &Exp2; + + if (TLI->has(LibFunc::floor) && TLI->has(LibFunc::floorf)) + Optimizations["floor"] = &UnaryDoubleFP; + if (TLI->has(LibFunc::ceil) && TLI->has(LibFunc::ceilf)) + Optimizations["ceil"] = &UnaryDoubleFP; + if (TLI->has(LibFunc::round) && TLI->has(LibFunc::roundf)) + Optimizations["round"] = &UnaryDoubleFP; + if (TLI->has(LibFunc::rint) && TLI->has(LibFunc::rintf)) + Optimizations["rint"] = &UnaryDoubleFP; + if (TLI->has(LibFunc::nearbyint) && TLI->has(LibFunc::nearbyintf)) + Optimizations["nearbyint"] = &UnaryDoubleFP; + + // Integer Optimizations + Optimizations["ffs"] = &FFS; + Optimizations["ffsl"] = &FFS; + Optimizations["ffsll"] = &FFS; + Optimizations["abs"] = &Abs; + Optimizations["labs"] = &Abs; + Optimizations["llabs"] = &Abs; + Optimizations["isdigit"] = &IsDigit; + Optimizations["isascii"] = &IsAscii; + Optimizations["toascii"] = &ToAscii; + + // Formatting and IO Optimizations + Optimizations["sprintf"] = &SPrintF; + Optimizations["printf"] = &PrintF; + AddOpt(LibFunc::fwrite, &FWrite); + AddOpt(LibFunc::fputs, &FPuts); + Optimizations["fprintf"] = &FPrintF; + Optimizations["puts"] = &Puts; +} + + +/// runOnFunction - Top level algorithm. +/// +bool SimplifyLibCalls::runOnFunction(Function &F) { + TLI = &getAnalysis<TargetLibraryInfo>(); + + if (Optimizations.empty()) + InitOptimizations(); + + const TargetData *TD = getAnalysisIfAvailable<TargetData>(); + + IRBuilder<> Builder(F.getContext()); + + bool Changed = false; + for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB) { + for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ) { + // Ignore non-calls. + CallInst *CI = dyn_cast<CallInst>(I++); + if (!CI) continue; + + // Ignore indirect calls and calls to non-external functions. + Function *Callee = CI->getCalledFunction(); + if (Callee == 0 || !Callee->isDeclaration() || + !(Callee->hasExternalLinkage() || Callee->hasDLLImportLinkage())) + continue; + + // Ignore unknown calls. + LibCallOptimization *LCO = Optimizations.lookup(Callee->getName()); + if (!LCO) continue; + + // Set the builder to the instruction after the call. + Builder.SetInsertPoint(BB, I); + + // Use debug location of CI for all new instructions. + Builder.SetCurrentDebugLocation(CI->getDebugLoc()); + + // Try to optimize this call. + Value *Result = LCO->OptimizeCall(CI, TD, TLI, Builder); + if (Result == 0) continue; + + DEBUG(dbgs() << "SimplifyLibCalls simplified: " << *CI; + dbgs() << " into: " << *Result << "\n"); + + // Something changed! + Changed = true; + ++NumSimplified; + + // Inspect the instruction after the call (which was potentially just + // added) next. + I = CI; ++I; + + if (CI != Result && !CI->use_empty()) { + CI->replaceAllUsesWith(Result); + if (!Result->hasName()) + Result->takeName(CI); + } + CI->eraseFromParent(); + } + } + return Changed; +} + +// Utility methods for doInitialization. + +void SimplifyLibCalls::setDoesNotAccessMemory(Function &F) { + if (!F.doesNotAccessMemory()) { + F.setDoesNotAccessMemory(); + ++NumAnnotated; + Modified = true; + } +} +void SimplifyLibCalls::setOnlyReadsMemory(Function &F) { + if (!F.onlyReadsMemory()) { + F.setOnlyReadsMemory(); + ++NumAnnotated; + Modified = true; + } +} +void SimplifyLibCalls::setDoesNotThrow(Function &F) { + if (!F.doesNotThrow()) { + F.setDoesNotThrow(); + ++NumAnnotated; + Modified = true; + } +} +void SimplifyLibCalls::setDoesNotCapture(Function &F, unsigned n) { + if (!F.doesNotCapture(n)) { + F.setDoesNotCapture(n); + ++NumAnnotated; + Modified = true; + } +} +void SimplifyLibCalls::setDoesNotAlias(Function &F, unsigned n) { + if (!F.doesNotAlias(n)) { + F.setDoesNotAlias(n); + ++NumAnnotated; + Modified = true; + } +} + + +void SimplifyLibCalls::inferPrototypeAttributes(Function &F) { + FunctionType *FTy = F.getFunctionType(); + + StringRef Name = F.getName(); + switch (Name[0]) { + case 's': + if (Name == "strlen") { + if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy()) + return; + setOnlyReadsMemory(F); + setDoesNotThrow(F); + setDoesNotCapture(F, 1); + } else if (Name == "strchr" || + Name == "strrchr") { + if (FTy->getNumParams() != 2 || + !FTy->getParamType(0)->isPointerTy() || + !FTy->getParamType(1)->isIntegerTy()) + return; + setOnlyReadsMemory(F); + setDoesNotThrow(F); + } else if (Name == "strcpy" || + Name == "stpcpy" || + Name == "strcat" || + Name == "strtol" || + Name == "strtod" || + Name == "strtof" || + Name == "strtoul" || + Name == "strtoll" || + Name == "strtold" || + Name == "strncat" || + Name == "strncpy" || + Name == "stpncpy" || + Name == "strtoull") { + if (FTy->getNumParams() < 2 || + !FTy->getParamType(1)->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotCapture(F, 2); + } else if (Name == "strxfrm") { + if (FTy->getNumParams() != 3 || + !FTy->getParamType(0)->isPointerTy() || + !FTy->getParamType(1)->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotCapture(F, 1); + setDoesNotCapture(F, 2); + } else if (Name == "strcmp" || + Name == "strspn" || + Name == "strncmp" || + Name == "strcspn" || + Name == "strcoll" || + Name == "strcasecmp" || + Name == "strncasecmp") { + if (FTy->getNumParams() < 2 || + !FTy->getParamType(0)->isPointerTy() || + !FTy->getParamType(1)->isPointerTy()) + return; + setOnlyReadsMemory(F); + setDoesNotThrow(F); + setDoesNotCapture(F, 1); + setDoesNotCapture(F, 2); + } else if (Name == "strstr" || + Name == "strpbrk") { + if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy()) + return; + setOnlyReadsMemory(F); + setDoesNotThrow(F); + setDoesNotCapture(F, 2); + } else if (Name == "strtok" || + Name == "strtok_r") { + if (FTy->getNumParams() < 2 || !FTy->getParamType(1)->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotCapture(F, 2); + } else if (Name == "scanf" || + Name == "setbuf" || + Name == "setvbuf") { + if (FTy->getNumParams() < 1 || !FTy->getParamType(0)->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotCapture(F, 1); + } else if (Name == "strdup" || + Name == "strndup") { + if (FTy->getNumParams() < 1 || !FTy->getReturnType()->isPointerTy() || + !FTy->getParamType(0)->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotAlias(F, 0); + setDoesNotCapture(F, 1); + } else if (Name == "stat" || + Name == "sscanf" || + Name == "sprintf" || + Name == "statvfs") { + if (FTy->getNumParams() < 2 || + !FTy->getParamType(0)->isPointerTy() || + !FTy->getParamType(1)->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotCapture(F, 1); + setDoesNotCapture(F, 2); + } else if (Name == "snprintf") { + if (FTy->getNumParams() != 3 || + !FTy->getParamType(0)->isPointerTy() || + !FTy->getParamType(2)->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotCapture(F, 1); + setDoesNotCapture(F, 3); + } else if (Name == "setitimer") { + if (FTy->getNumParams() != 3 || + !FTy->getParamType(1)->isPointerTy() || + !FTy->getParamType(2)->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotCapture(F, 2); + setDoesNotCapture(F, 3); + } else if (Name == "system") { + if (FTy->getNumParams() != 1 || + !FTy->getParamType(0)->isPointerTy()) + return; + // May throw; "system" is a valid pthread cancellation point. + setDoesNotCapture(F, 1); + } + break; + case 'm': + if (Name == "malloc") { + if (FTy->getNumParams() != 1 || + !FTy->getReturnType()->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotAlias(F, 0); + } else if (Name == "memcmp") { + if (FTy->getNumParams() != 3 || + !FTy->getParamType(0)->isPointerTy() || + !FTy->getParamType(1)->isPointerTy()) + return; + setOnlyReadsMemory(F); + setDoesNotThrow(F); + setDoesNotCapture(F, 1); + setDoesNotCapture(F, 2); + } else if (Name == "memchr" || + Name == "memrchr") { + if (FTy->getNumParams() != 3) + return; + setOnlyReadsMemory(F); + setDoesNotThrow(F); + } else if (Name == "modf" || + Name == "modff" || + Name == "modfl" || + Name == "memcpy" || + Name == "memccpy" || + Name == "memmove") { + if (FTy->getNumParams() < 2 || + !FTy->getParamType(1)->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotCapture(F, 2); + } else if (Name == "memalign") { + if (!FTy->getReturnType()->isPointerTy()) + return; + setDoesNotAlias(F, 0); + } else if (Name == "mkdir" || + Name == "mktime") { + if (FTy->getNumParams() == 0 || + !FTy->getParamType(0)->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotCapture(F, 1); + } + break; + case 'r': + if (Name == "realloc") { + if (FTy->getNumParams() != 2 || + !FTy->getParamType(0)->isPointerTy() || + !FTy->getReturnType()->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotAlias(F, 0); + setDoesNotCapture(F, 1); + } else if (Name == "read") { + if (FTy->getNumParams() != 3 || + !FTy->getParamType(1)->isPointerTy()) + return; + // May throw; "read" is a valid pthread cancellation point. + setDoesNotCapture(F, 2); + } else if (Name == "rmdir" || + Name == "rewind" || + Name == "remove" || + Name == "realpath") { + if (FTy->getNumParams() < 1 || + !FTy->getParamType(0)->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotCapture(F, 1); + } else if (Name == "rename" || + Name == "readlink") { + if (FTy->getNumParams() < 2 || + !FTy->getParamType(0)->isPointerTy() || + !FTy->getParamType(1)->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotCapture(F, 1); + setDoesNotCapture(F, 2); + } + break; + case 'w': + if (Name == "write") { + if (FTy->getNumParams() != 3 || !FTy->getParamType(1)->isPointerTy()) + return; + // May throw; "write" is a valid pthread cancellation point. + setDoesNotCapture(F, 2); + } + break; + case 'b': + if (Name == "bcopy") { + if (FTy->getNumParams() != 3 || + !FTy->getParamType(0)->isPointerTy() || + !FTy->getParamType(1)->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotCapture(F, 1); + setDoesNotCapture(F, 2); + } else if (Name == "bcmp") { + if (FTy->getNumParams() != 3 || + !FTy->getParamType(0)->isPointerTy() || + !FTy->getParamType(1)->isPointerTy()) + return; + setDoesNotThrow(F); + setOnlyReadsMemory(F); + setDoesNotCapture(F, 1); + setDoesNotCapture(F, 2); + } else if (Name == "bzero") { + if (FTy->getNumParams() != 2 || !FTy->getParamType(0)->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotCapture(F, 1); + } + break; + case 'c': + if (Name == "calloc") { + if (FTy->getNumParams() != 2 || + !FTy->getReturnType()->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotAlias(F, 0); + } else if (Name == "chmod" || + Name == "chown" || + Name == "ctermid" || + Name == "clearerr" || + Name == "closedir") { + if (FTy->getNumParams() == 0 || !FTy->getParamType(0)->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotCapture(F, 1); + } + break; + case 'a': + if (Name == "atoi" || + Name == "atol" || + Name == "atof" || + Name == "atoll") { + if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy()) + return; + setDoesNotThrow(F); + setOnlyReadsMemory(F); + setDoesNotCapture(F, 1); + } else if (Name == "access") { + if (FTy->getNumParams() != 2 || !FTy->getParamType(0)->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotCapture(F, 1); + } + break; + case 'f': + if (Name == "fopen") { + if (FTy->getNumParams() != 2 || + !FTy->getReturnType()->isPointerTy() || + !FTy->getParamType(0)->isPointerTy() || + !FTy->getParamType(1)->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotAlias(F, 0); + setDoesNotCapture(F, 1); + setDoesNotCapture(F, 2); + } else if (Name == "fdopen") { + if (FTy->getNumParams() != 2 || + !FTy->getReturnType()->isPointerTy() || + !FTy->getParamType(1)->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotAlias(F, 0); + setDoesNotCapture(F, 2); + } else if (Name == "feof" || + Name == "free" || + Name == "fseek" || + Name == "ftell" || + Name == "fgetc" || + Name == "fseeko" || + Name == "ftello" || + Name == "fileno" || + Name == "fflush" || + Name == "fclose" || + Name == "fsetpos" || + Name == "flockfile" || + Name == "funlockfile" || + Name == "ftrylockfile") { + if (FTy->getNumParams() == 0 || !FTy->getParamType(0)->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotCapture(F, 1); + } else if (Name == "ferror") { + if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotCapture(F, 1); + setOnlyReadsMemory(F); + } else if (Name == "fputc" || + Name == "fstat" || + Name == "frexp" || + Name == "frexpf" || + Name == "frexpl" || + Name == "fstatvfs") { + if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotCapture(F, 2); + } else if (Name == "fgets") { + if (FTy->getNumParams() != 3 || + !FTy->getParamType(0)->isPointerTy() || + !FTy->getParamType(2)->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotCapture(F, 3); + } else if (Name == "fread" || + Name == "fwrite") { + if (FTy->getNumParams() != 4 || + !FTy->getParamType(0)->isPointerTy() || + !FTy->getParamType(3)->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotCapture(F, 1); + setDoesNotCapture(F, 4); + } else if (Name == "fputs" || + Name == "fscanf" || + Name == "fprintf" || + Name == "fgetpos") { + if (FTy->getNumParams() < 2 || + !FTy->getParamType(0)->isPointerTy() || + !FTy->getParamType(1)->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotCapture(F, 1); + setDoesNotCapture(F, 2); + } + break; + case 'g': + if (Name == "getc" || + Name == "getlogin_r" || + Name == "getc_unlocked") { + if (FTy->getNumParams() == 0 || !FTy->getParamType(0)->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotCapture(F, 1); + } else if (Name == "getenv") { + if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy()) + return; + setDoesNotThrow(F); + setOnlyReadsMemory(F); + setDoesNotCapture(F, 1); + } else if (Name == "gets" || + Name == "getchar") { + setDoesNotThrow(F); + } else if (Name == "getitimer") { + if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotCapture(F, 2); + } else if (Name == "getpwnam") { + if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotCapture(F, 1); + } + break; + case 'u': + if (Name == "ungetc") { + if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotCapture(F, 2); + } else if (Name == "uname" || + Name == "unlink" || + Name == "unsetenv") { + if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotCapture(F, 1); + } else if (Name == "utime" || + Name == "utimes") { + if (FTy->getNumParams() != 2 || + !FTy->getParamType(0)->isPointerTy() || + !FTy->getParamType(1)->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotCapture(F, 1); + setDoesNotCapture(F, 2); + } + break; + case 'p': + if (Name == "putc") { + if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotCapture(F, 2); + } else if (Name == "puts" || + Name == "printf" || + Name == "perror") { + if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotCapture(F, 1); + } else if (Name == "pread" || + Name == "pwrite") { + if (FTy->getNumParams() != 4 || !FTy->getParamType(1)->isPointerTy()) + return; + // May throw; these are valid pthread cancellation points. + setDoesNotCapture(F, 2); + } else if (Name == "putchar") { + setDoesNotThrow(F); + } else if (Name == "popen") { + if (FTy->getNumParams() != 2 || + !FTy->getReturnType()->isPointerTy() || + !FTy->getParamType(0)->isPointerTy() || + !FTy->getParamType(1)->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotAlias(F, 0); + setDoesNotCapture(F, 1); + setDoesNotCapture(F, 2); + } else if (Name == "pclose") { + if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotCapture(F, 1); + } + break; + case 'v': + if (Name == "vscanf") { + if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotCapture(F, 1); + } else if (Name == "vsscanf" || + Name == "vfscanf") { + if (FTy->getNumParams() != 3 || + !FTy->getParamType(1)->isPointerTy() || + !FTy->getParamType(2)->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotCapture(F, 1); + setDoesNotCapture(F, 2); + } else if (Name == "valloc") { + if (!FTy->getReturnType()->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotAlias(F, 0); + } else if (Name == "vprintf") { + if (FTy->getNumParams() != 2 || !FTy->getParamType(0)->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotCapture(F, 1); + } else if (Name == "vfprintf" || + Name == "vsprintf") { + if (FTy->getNumParams() != 3 || + !FTy->getParamType(0)->isPointerTy() || + !FTy->getParamType(1)->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotCapture(F, 1); + setDoesNotCapture(F, 2); + } else if (Name == "vsnprintf") { + if (FTy->getNumParams() != 4 || + !FTy->getParamType(0)->isPointerTy() || + !FTy->getParamType(2)->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotCapture(F, 1); + setDoesNotCapture(F, 3); + } + break; + case 'o': + if (Name == "open") { + if (FTy->getNumParams() < 2 || !FTy->getParamType(0)->isPointerTy()) + return; + // May throw; "open" is a valid pthread cancellation point. + setDoesNotCapture(F, 1); + } else if (Name == "opendir") { + if (FTy->getNumParams() != 1 || + !FTy->getReturnType()->isPointerTy() || + !FTy->getParamType(0)->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotAlias(F, 0); + setDoesNotCapture(F, 1); + } + break; + case 't': + if (Name == "tmpfile") { + if (!FTy->getReturnType()->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotAlias(F, 0); + } else if (Name == "times") { + if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotCapture(F, 1); + } + break; + case 'h': + if (Name == "htonl" || + Name == "htons") { + setDoesNotThrow(F); + setDoesNotAccessMemory(F); + } + break; + case 'n': + if (Name == "ntohl" || + Name == "ntohs") { + setDoesNotThrow(F); + setDoesNotAccessMemory(F); + } + break; + case 'l': + if (Name == "lstat") { + if (FTy->getNumParams() != 2 || + !FTy->getParamType(0)->isPointerTy() || + !FTy->getParamType(1)->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotCapture(F, 1); + setDoesNotCapture(F, 2); + } else if (Name == "lchown") { + if (FTy->getNumParams() != 3 || !FTy->getParamType(0)->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotCapture(F, 1); + } + break; + case 'q': + if (Name == "qsort") { + if (FTy->getNumParams() != 4 || !FTy->getParamType(3)->isPointerTy()) + return; + // May throw; places call through function pointer. + setDoesNotCapture(F, 4); + } + break; + case '_': + if (Name == "__strdup" || + Name == "__strndup") { + if (FTy->getNumParams() < 1 || + !FTy->getReturnType()->isPointerTy() || + !FTy->getParamType(0)->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotAlias(F, 0); + setDoesNotCapture(F, 1); + } else if (Name == "__strtok_r") { + if (FTy->getNumParams() != 3 || + !FTy->getParamType(1)->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotCapture(F, 2); + } else if (Name == "_IO_getc") { + if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotCapture(F, 1); + } else if (Name == "_IO_putc") { + if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotCapture(F, 2); + } + break; + case 1: + if (Name == "\1__isoc99_scanf") { + if (FTy->getNumParams() < 1 || + !FTy->getParamType(0)->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotCapture(F, 1); + } else if (Name == "\1stat64" || + Name == "\1lstat64" || + Name == "\1statvfs64" || + Name == "\1__isoc99_sscanf") { + if (FTy->getNumParams() < 1 || + !FTy->getParamType(0)->isPointerTy() || + !FTy->getParamType(1)->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotCapture(F, 1); + setDoesNotCapture(F, 2); + } else if (Name == "\1fopen64") { + if (FTy->getNumParams() != 2 || + !FTy->getReturnType()->isPointerTy() || + !FTy->getParamType(0)->isPointerTy() || + !FTy->getParamType(1)->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotAlias(F, 0); + setDoesNotCapture(F, 1); + setDoesNotCapture(F, 2); + } else if (Name == "\1fseeko64" || + Name == "\1ftello64") { + if (FTy->getNumParams() == 0 || !FTy->getParamType(0)->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotCapture(F, 1); + } else if (Name == "\1tmpfile64") { + if (!FTy->getReturnType()->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotAlias(F, 0); + } else if (Name == "\1fstat64" || + Name == "\1fstatvfs64") { + if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy()) + return; + setDoesNotThrow(F); + setDoesNotCapture(F, 2); + } else if (Name == "\1open64") { + if (FTy->getNumParams() < 2 || !FTy->getParamType(0)->isPointerTy()) + return; + // May throw; "open" is a valid pthread cancellation point. + setDoesNotCapture(F, 1); + } + break; + } +} + +/// doInitialization - Add attributes to well-known functions. +/// +bool SimplifyLibCalls::doInitialization(Module &M) { + Modified = false; + for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I) { + Function &F = *I; + if (F.isDeclaration() && F.hasName()) + inferPrototypeAttributes(F); + } + return Modified; +} + +// TODO: +// Additional cases that we need to add to this file: +// +// cbrt: +// * cbrt(expN(X)) -> expN(x/3) +// * cbrt(sqrt(x)) -> pow(x,1/6) +// * cbrt(sqrt(x)) -> pow(x,1/9) +// +// exp, expf, expl: +// * exp(log(x)) -> x +// +// log, logf, logl: +// * log(exp(x)) -> x +// * log(x**y) -> y*log(x) +// * log(exp(y)) -> y*log(e) +// * log(exp2(y)) -> y*log(2) +// * log(exp10(y)) -> y*log(10) +// * log(sqrt(x)) -> 0.5*log(x) +// * log(pow(x,y)) -> y*log(x) +// +// lround, lroundf, lroundl: +// * lround(cnst) -> cnst' +// +// pow, powf, powl: +// * pow(exp(x),y) -> exp(x*y) +// * pow(sqrt(x),y) -> pow(x,y*0.5) +// * pow(pow(x,y),z)-> pow(x,y*z) +// +// round, roundf, roundl: +// * round(cnst) -> cnst' +// +// signbit: +// * signbit(cnst) -> cnst' +// * signbit(nncst) -> 0 (if pstv is a non-negative constant) +// +// sqrt, sqrtf, sqrtl: +// * sqrt(expN(x)) -> expN(x*0.5) +// * sqrt(Nroot(x)) -> pow(x,1/(2*N)) +// * sqrt(pow(x,y)) -> pow(|x|,y*0.5) +// +// strchr: +// * strchr(p, 0) -> strlen(p) +// tan, tanf, tanl: +// * tan(atan(x)) -> x +// +// trunc, truncf, truncl: +// * trunc(cnst) -> cnst' +// +// |
