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llvm-6502/lib/Transforms/Scalar/SimplifyLibCalls.cpp
Chandler Carruth 06cb8ed006 Move llvm/Support/IRBuilder.h -> llvm/IRBuilder.h 
This was always part of the VMCore library out of necessity -- it deals
entirely in the IR. The .cpp file in fact was already part of the VMCore
library. This is just a mechanical move.

I've tried to go through and re-apply the coding standard's preferred
header sort, but at 40-ish files, I may have gotten some wrong. Please
let me know if so.

I'll be committing the corresponding updates to Clang and Polly, and
Duncan has DragonEgg.

Thanks to Bill and Eric for giving the green light for this bit of cleanup.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@159421 91177308-0d34-0410-b5e6-96231b3b80d8
2012-06-29 12:38:19 +00:00

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//===- 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;
EmitStrLenMemCpy(Src, Dst, Len, B);
return Dst;
}
void 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);
// 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);
}
};
//===---------------------------------------===//
// '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
EmitStrLenMemCpy(Src, Dst, SrcLen, B);
return Dst;
}
};
//===---------------------------------------===//
// '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);
}
// 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);
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);
}
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);
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);
else
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)
return B.CreateInBoundsGEP(Dst, EmitStrLen(Src, B, TD));
// 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);
else
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);
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);
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);
Value *StrNCmp = EmitStrNCmp(CI->getArgOperand(0), CI->getArgOperand(1),
StrLen, B, TD);
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)
return B.CreateBitCast(EmitStrChr(CI->getArgOperand(0),
ToFindStr[0], B, TD), CI->getType());
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);
if (CI->use_empty()) return CI;
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");
EmitPutS(GV, B, TD);
return CI->use_empty() ? (Value*)CI :
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);
if (CI->use_empty()) return CI;
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()) {
EmitPutS(CI->getArgOperand(1), B, TD);
return CI;
}
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);
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");
EmitFPutC(Char, CI->getArgOperand(3), B, TD);
return ConstantInt::get(CI->getType(), 1);
}
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;
EmitFWrite(CI->getArgOperand(0),
ConstantInt::get(TD->getIntPtrType(*Context), Len-1),
CI->getArgOperand(1), B, TD, TLI);
return CI; // Known to have no uses (see above).
}
};
//===---------------------------------------===//
// '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;
EmitFWrite(CI->getArgOperand(1),
ConstantInt::get(TD->getIntPtrType(*Context),
FormatStr.size()),
CI->getArgOperand(0), B, TD, TLI);
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') {
// fprintf(F, "%c", chr) --> fputc(chr, F)
if (!CI->getArgOperand(2)->getType()->isIntegerTy()) return 0;
EmitFPutC(CI->getArgOperand(2), CI->getArgOperand(0), B, TD);
return ConstantInt::get(CI->getType(), 1);
}
if (FormatStr[1] == 's') {
// fprintf(F, "%s", str) --> fputs(str, F)
if (!CI->getArgOperand(2)->getType()->isPointerTy() || !CI->use_empty())
return 0;
EmitFPutS(CI->getArgOperand(2), CI->getArgOperand(0), B, TD, TLI);
return CI;
}
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);
if (CI->use_empty()) return CI;
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'
//
//
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