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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/Intrinsics.h"
+#include "llvm/LLVMContext.h"
+#include "llvm/Module.h"
+#include "llvm/Pass.h"
+#include "llvm/Support/IRBuilder.h"
+#include "llvm/Analysis/ValueTracking.h"
+#include "llvm/Target/TargetData.h"
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/ADT/StringMap.h"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Config/config.h"
+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;
+ 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, IRBuilder<> &B) {
+ Caller = CI->getParent()->getParent();
+ this->TD = TD;
+ if (CI->getCalledFunction())
+ Context = &CI->getCalledFunction()->getContext();
+ 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;
+}
+
+//===----------------------------------------------------------------------===//
+// 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.
+ const FunctionType *FT = Callee->getFunctionType();
+ if (FT->getNumParams() != 2 ||
+ FT->getReturnType() != Type::getInt8PtrTy(*Context) ||
+ FT->getParamType(0) != FT->getReturnType() ||
+ FT->getParamType(1) != FT->getReturnType())
+ return 0;
+
+ // Extract some information from the instruction
+ Value *Dst = CI->getOperand(1);
+ Value *Src = CI->getOperand(2);
+
+ // 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.
+ EmitMemCpy(CpyDst, Src,
+ ConstantInt::get(TD->getIntPtrType(*Context), Len+1),
+ 1, false, B, TD);
+ }
+};
+
+//===---------------------------------------===//
+// 'strncat' Optimizations
+
+struct StrNCatOpt : public StrCatOpt {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
+ // Verify the "strncat" function prototype.
+ const FunctionType *FT = Callee->getFunctionType();
+ if (FT->getNumParams() != 3 ||
+ FT->getReturnType() != Type::getInt8PtrTy(*Context) ||
+ 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->getOperand(1);
+ Value *Src = CI->getOperand(2);
+ uint64_t Len;
+
+ // We don't do anything if length is not constant
+ if (ConstantInt *LengthArg = dyn_cast<ConstantInt>(CI->getOperand(3)))
+ 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.
+ const FunctionType *FT = Callee->getFunctionType();
+ if (FT->getNumParams() != 2 ||
+ FT->getReturnType() != Type::getInt8PtrTy(*Context) ||
+ FT->getParamType(0) != FT->getReturnType())
+ return 0;
+
+ Value *SrcStr = CI->getOperand(1);
+
+ // 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->getOperand(2));
+ 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->getOperand(2), // 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.
+ std::string Str;
+ if (!GetConstantStringInfo(SrcStr, Str))
+ return 0;
+
+ // strchr can find the nul character.
+ Str += '\0';
+ char CharValue = CharC->getSExtValue();
+
+ // Compute the offset.
+ uint64_t i = 0;
+ while (1) {
+ if (i == Str.size()) // Didn't find the char. strchr returns null.
+ return Constant::getNullValue(CI->getType());
+ // Did we find our match?
+ if (Str[i] == CharValue)
+ break;
+ ++i;
+ }
+
+ // strchr(s+n,c) -> gep(s+n+i,c)
+ Value *Idx = ConstantInt::get(Type::getInt64Ty(*Context), i);
+ return B.CreateGEP(SrcStr, Idx, "strchr");
+ }
+};
+
+//===---------------------------------------===//
+// 'strcmp' Optimizations
+
+struct StrCmpOpt : public LibCallOptimization {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
+ // Verify the "strcmp" function prototype.
+ const FunctionType *FT = Callee->getFunctionType();
+ if (FT->getNumParams() != 2 ||
+ !FT->getReturnType()->isIntegerTy(32) ||
+ FT->getParamType(0) != FT->getParamType(1) ||
+ FT->getParamType(0) != Type::getInt8PtrTy(*Context))
+ return 0;
+
+ Value *Str1P = CI->getOperand(1), *Str2P = CI->getOperand(2);
+ if (Str1P == Str2P) // strcmp(x,x) -> 0
+ return ConstantInt::get(CI->getType(), 0);
+
+ std::string Str1, Str2;
+ bool HasStr1 = GetConstantStringInfo(Str1P, Str1);
+ bool HasStr2 = GetConstantStringInfo(Str2P, Str2);
+
+ if (HasStr1 && Str1.empty()) // strcmp("", x) -> *x
+ return 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(x, y) -> cnst (if both x and y are constant strings)
+ if (HasStr1 && HasStr2)
+ return ConstantInt::get(CI->getType(),
+ strcmp(Str1.c_str(),Str2.c_str()));
+
+ // 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.
+ const FunctionType *FT = Callee->getFunctionType();
+ if (FT->getNumParams() != 3 ||
+ !FT->getReturnType()->isIntegerTy(32) ||
+ FT->getParamType(0) != FT->getParamType(1) ||
+ FT->getParamType(0) != Type::getInt8PtrTy(*Context) ||
+ !FT->getParamType(2)->isIntegerTy())
+ return 0;
+
+ Value *Str1P = CI->getOperand(1), *Str2P = CI->getOperand(2);
+ 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->getOperand(3)))
+ Length = LengthArg->getZExtValue();
+ else
+ return 0;
+
+ if (Length == 0) // strncmp(x,y,0) -> 0
+ return ConstantInt::get(CI->getType(), 0);
+
+ std::string Str1, Str2;
+ bool HasStr1 = GetConstantStringInfo(Str1P, Str1);
+ bool HasStr2 = GetConstantStringInfo(Str2P, Str2);
+
+ if (HasStr1 && Str1.empty()) // strncmp("", x, n) -> *x
+ return 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());
+
+ // strncmp(x, y) -> cnst (if both x and y are constant strings)
+ if (HasStr1 && HasStr2)
+ return ConstantInt::get(CI->getType(),
+ strncmp(Str1.c_str(), Str2.c_str(), Length));
+ 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;
+ const FunctionType *FT = Callee->getFunctionType();
+ if (FT->getNumParams() != NumParams ||
+ FT->getReturnType() != FT->getParamType(0) ||
+ FT->getParamType(0) != FT->getParamType(1) ||
+ FT->getParamType(0) != Type::getInt8PtrTy(*Context))
+ return 0;
+
+ Value *Dst = CI->getOperand(1), *Src = CI->getOperand(2);
+ 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->getOperand(3), B, TD);
+ else
+ EmitMemCpy(Dst, Src,
+ ConstantInt::get(TD->getIntPtrType(*Context), Len),
+ 1, false, B, TD);
+ return Dst;
+ }
+};
+
+//===---------------------------------------===//
+// 'strncpy' Optimizations
+
+struct StrNCpyOpt : public LibCallOptimization {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
+ const FunctionType *FT = Callee->getFunctionType();
+ if (FT->getNumParams() != 3 || FT->getReturnType() != FT->getParamType(0) ||
+ FT->getParamType(0) != FT->getParamType(1) ||
+ FT->getParamType(0) != Type::getInt8PtrTy(*Context) ||
+ !FT->getParamType(2)->isIntegerTy())
+ return 0;
+
+ Value *Dst = CI->getOperand(1);
+ Value *Src = CI->getOperand(2);
+ Value *LenOp = CI->getOperand(3);
+
+ // 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)
+ EmitMemSet(Dst, ConstantInt::get(Type::getInt8Ty(*Context), '\0'),
+ LenOp, false, B, TD);
+ 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]
+ EmitMemCpy(Dst, Src,
+ ConstantInt::get(TD->getIntPtrType(*Context), Len),
+ 1, false, B, TD);
+
+ return Dst;
+ }
+};
+
+//===---------------------------------------===//
+// 'strlen' Optimizations
+
+struct StrLenOpt : public LibCallOptimization {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
+ const FunctionType *FT = Callee->getFunctionType();
+ if (FT->getNumParams() != 1 ||
+ FT->getParamType(0) != Type::getInt8PtrTy(*Context) ||
+ !FT->getReturnType()->isIntegerTy())
+ return 0;
+
+ Value *Src = CI->getOperand(1);
+
+ // 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;
+ }
+};
+
+//===---------------------------------------===//
+// 'strto*' Optimizations. This handles strtol, strtod, strtof, strtoul, etc.
+
+struct StrToOpt : public LibCallOptimization {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
+ const FunctionType *FT = Callee->getFunctionType();
+ if ((FT->getNumParams() != 2 && FT->getNumParams() != 3) ||
+ !FT->getParamType(0)->isPointerTy() ||
+ !FT->getParamType(1)->isPointerTy())
+ return 0;
+
+ Value *EndPtr = CI->getOperand(2);
+ if (isa<ConstantPointerNull>(EndPtr)) {
+ CI->setOnlyReadsMemory();
+ CI->addAttribute(1, Attribute::NoCapture);
+ }
+
+ return 0;
+ }
+};
+
+//===---------------------------------------===//
+// 'strstr' Optimizations
+
+struct StrStrOpt : public LibCallOptimization {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
+ const 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->getOperand(1) == CI->getOperand(2))
+ return B.CreateBitCast(CI->getOperand(1), CI->getType());
+
+ // See if either input string is a constant string.
+ std::string SearchStr, ToFindStr;
+ bool HasStr1 = GetConstantStringInfo(CI->getOperand(1), SearchStr);
+ bool HasStr2 = GetConstantStringInfo(CI->getOperand(2), ToFindStr);
+
+ // fold strstr(x, "") -> x.
+ if (HasStr2 && ToFindStr.empty())
+ return B.CreateBitCast(CI->getOperand(1), CI->getType());
+
+ // If both strings are known, constant fold it.
+ if (HasStr1 && HasStr2) {
+ std::string::size_type Offset = SearchStr.find(ToFindStr);
+
+ if (Offset == std::string::npos) // strstr("foo", "bar") -> null
+ return Constant::getNullValue(CI->getType());
+
+ // strstr("abcd", "bc") -> gep((char*)"abcd", 1)
+ Value *Result = CastToCStr(CI->getOperand(1), 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->getOperand(1), ToFindStr[0], B, TD),
+ CI->getType());
+ return 0;
+ }
+};
+
+
+//===---------------------------------------===//
+// 'memcmp' Optimizations
+
+struct MemCmpOpt : public LibCallOptimization {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
+ const 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->getOperand(1), *RHS = CI->getOperand(2);
+
+ 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->getOperand(3));
+ 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)
+ std::string LHSStr, RHSStr;
+ if (GetConstantStringInfo(LHS, LHSStr) &&
+ GetConstantStringInfo(RHS, RHSStr)) {
+ // Make sure we're not reading out-of-bounds memory.
+ if (Len > LHSStr.length() || Len > RHSStr.length())
+ 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;
+
+ const 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)
+ EmitMemCpy(CI->getOperand(1), CI->getOperand(2),
+ CI->getOperand(3), 1, false, B, TD);
+ return CI->getOperand(1);
+ }
+};
+
+//===---------------------------------------===//
+// 'memmove' Optimizations
+
+struct MemMoveOpt : public LibCallOptimization {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
+ // These optimizations require TargetData.
+ if (!TD) return 0;
+
+ const 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)
+ EmitMemMove(CI->getOperand(1), CI->getOperand(2),
+ CI->getOperand(3), 1, false, B, TD);
+ return CI->getOperand(1);
+ }
+};
+
+//===---------------------------------------===//
+// 'memset' Optimizations
+
+struct MemSetOpt : public LibCallOptimization {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
+ // These optimizations require TargetData.
+ if (!TD) return 0;
+
+ const 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->getOperand(2), Type::getInt8Ty(*Context),
+ false);
+ EmitMemSet(CI->getOperand(1), Val, CI->getOperand(3), false, B, TD);
+ return CI->getOperand(1);
+ }
+};
+
+//===----------------------------------------------------------------------===//
+// Math Library Optimizations
+//===----------------------------------------------------------------------===//
+
+//===---------------------------------------===//
+// 'pow*' Optimizations
+
+struct PowOpt : public LibCallOptimization {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
+ const 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->getOperand(1), *Op2 = CI->getOperand(2);
+ 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 infinite 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, "tmp");
+ Value *Sel = B.CreateSelect(FCmp, Inf, FAbs, "tmp");
+ 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) {
+ const 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->getOperand(1);
+ // 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),
+ Type::getInt32Ty(*Context), "tmp");
+ } else if (UIToFPInst *OpC = dyn_cast<UIToFPInst>(Op)) {
+ if (OpC->getOperand(0)->getType()->getPrimitiveSizeInBits() < 32)
+ LdExpArg = B.CreateZExt(OpC->getOperand(0),
+ Type::getInt32Ty(*Context), "tmp");
+ }
+
+ 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(),
+ Type::getInt32Ty(*Context),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) {
+ const 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->getOperand(1));
+ 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().data(), B,
+ Callee->getAttributes());
+ return B.CreateFPExt(V, Type::getDoubleTy(*Context));
+ }
+};
+
+//===----------------------------------------------------------------------===//
+// Integer Optimizations
+//===----------------------------------------------------------------------===//
+
+//===---------------------------------------===//
+// 'ffs*' Optimizations
+
+struct FFSOpt : public LibCallOptimization {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
+ const 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->getOperand(1);
+
+ // Constant fold.
+ if (ConstantInt *CI = dyn_cast<ConstantInt>(Op)) {
+ if (CI->getValue() == 0) // ffs(0) -> 0.
+ return Constant::getNullValue(CI->getType());
+ return ConstantInt::get(Type::getInt32Ty(*Context), // ffs(c) -> cttz(c)+1
+ CI->getValue().countTrailingZeros()+1);
+ }
+
+ // ffs(x) -> x != 0 ? (i32)llvm.cttz(x)+1 : 0
+ const Type *ArgType = Op->getType();
+ Value *F = Intrinsic::getDeclaration(Callee->getParent(),
+ Intrinsic::cttz, &ArgType, 1);
+ Value *V = B.CreateCall(F, Op, "cttz");
+ V = B.CreateAdd(V, ConstantInt::get(V->getType(), 1), "tmp");
+ V = B.CreateIntCast(V, Type::getInt32Ty(*Context), false, "tmp");
+
+ Value *Cond = B.CreateICmpNE(Op, Constant::getNullValue(ArgType), "tmp");
+ return B.CreateSelect(Cond, V,
+ ConstantInt::get(Type::getInt32Ty(*Context), 0));
+ }
+};
+
+//===---------------------------------------===//
+// 'isdigit' Optimizations
+
+struct IsDigitOpt : public LibCallOptimization {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
+ const 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->getOperand(1);
+ Op = B.CreateSub(Op, ConstantInt::get(Type::getInt32Ty(*Context), '0'),
+ "isdigittmp");
+ Op = B.CreateICmpULT(Op, ConstantInt::get(Type::getInt32Ty(*Context), 10),
+ "isdigit");
+ return B.CreateZExt(Op, CI->getType());
+ }
+};
+
+//===---------------------------------------===//
+// 'isascii' Optimizations
+
+struct IsAsciiOpt : public LibCallOptimization {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
+ const 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->getOperand(1);
+ Op = B.CreateICmpULT(Op, ConstantInt::get(Type::getInt32Ty(*Context), 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) {
+ const 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->getOperand(1);
+ 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) {
+ const 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->getOperand(1),
+ ConstantInt::get(CI->getType(),0x7F));
+ }
+};
+
+//===----------------------------------------------------------------------===//
+// Formatting and IO Optimizations
+//===----------------------------------------------------------------------===//
+
+//===---------------------------------------===//
+// 'printf' Optimizations
+
+struct PrintFOpt : public LibCallOptimization {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
+ // Require one fixed pointer argument and an integer/void result.
+ const FunctionType *FT = Callee->getFunctionType();
+ if (FT->getNumParams() < 1 || !FT->getParamType(0)->isPointerTy() ||
+ !(FT->getReturnType()->isIntegerTy() ||
+ FT->getReturnType()->isVoidTy()))
+ return 0;
+
+ // Check for a fixed format string.
+ std::string FormatStr;
+ if (!GetConstantStringInfo(CI->getOperand(1), 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);
+
+ // printf("x") -> putchar('x'), even for '%'. Return the result of putchar
+ // in case there is an error writing to stdout.
+ if (FormatStr.size() == 1) {
+ Value *Res = EmitPutChar(ConstantInt::get(Type::getInt32Ty(*Context),
+ 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.erase(FormatStr.end()-1);
+ Constant *C = ConstantArray::get(*Context, FormatStr, true);
+ C = new GlobalVariable(*Callee->getParent(), C->getType(), true,
+ GlobalVariable::InternalLinkage, C, "str");
+ EmitPutS(C, B, TD);
+ return CI->use_empty() ? (Value*)CI :
+ ConstantInt::get(CI->getType(), FormatStr.size()+1);
+ }
+
+ // Optimize specific format strings.
+ // printf("%c", chr) --> putchar(*(i8*)dst)
+ if (FormatStr == "%c" && CI->getNumOperands() > 2 &&
+ CI->getOperand(2)->getType()->isIntegerTy()) {
+ Value *Res = EmitPutChar(CI->getOperand(2), 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->getNumOperands() > 2 &&
+ CI->getOperand(2)->getType()->isPointerTy() &&
+ CI->use_empty()) {
+ EmitPutS(CI->getOperand(2), B, TD);
+ return CI;
+ }
+ return 0;
+ }
+};
+
+//===---------------------------------------===//
+// 'sprintf' Optimizations
+
+struct SPrintFOpt : public LibCallOptimization {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
+ // Require two fixed pointer arguments and an integer result.
+ const FunctionType *FT = Callee->getFunctionType();
+ if (FT->getNumParams() != 2 || !FT->getParamType(0)->isPointerTy() ||
+ !FT->getParamType(1)->isPointerTy() ||
+ !FT->getReturnType()->isIntegerTy())
+ return 0;
+
+ // Check for a fixed format string.
+ std::string FormatStr;
+ if (!GetConstantStringInfo(CI->getOperand(2), FormatStr))
+ return 0;
+
+ // If we just have a format string (nothing else crazy) transform it.
+ if (CI->getNumOperands() == 3) {
+ // 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)
+ EmitMemCpy(CI->getOperand(1), CI->getOperand(2), // Copy the nul byte.
+ ConstantInt::get(TD->getIntPtrType(*Context),
+ FormatStr.size()+1), 1, false, B, TD);
+ 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->getNumOperands() <4)
+ 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->getOperand(3)->getType()->isIntegerTy()) return 0;
+ Value *V = B.CreateTrunc(CI->getOperand(3),
+ Type::getInt8Ty(*Context), "char");
+ Value *Ptr = CastToCStr(CI->getOperand(1), B);
+ B.CreateStore(V, Ptr);
+ Ptr = B.CreateGEP(Ptr, ConstantInt::get(Type::getInt32Ty(*Context), 1),
+ "nul");
+ B.CreateStore(Constant::getNullValue(Type::getInt8Ty(*Context)), 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->getOperand(3)->getType()->isPointerTy()) return 0;
+
+ Value *Len = EmitStrLen(CI->getOperand(3), B, TD);
+ Value *IncLen = B.CreateAdd(Len,
+ ConstantInt::get(Len->getType(), 1),
+ "leninc");
+ EmitMemCpy(CI->getOperand(1), CI->getOperand(3), IncLen, 1, false, B, TD);
+
+ // The sprintf result is the unincremented number of bytes in the string.
+ return B.CreateIntCast(Len, CI->getType(), false);
+ }
+ 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.
+ const 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->getOperand(2));
+ ConstantInt *CountC = dyn_cast<ConstantInt>(CI->getOperand(3));
+ 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.
+ if (Bytes == 1) { // fwrite(S,1,1,F) -> fputc(S[0],F)
+ Value *Char = B.CreateLoad(CastToCStr(CI->getOperand(1), B), "char");
+ EmitFPutC(Char, CI->getOperand(4), 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.
+ const 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->getOperand(1));
+ if (!Len) return 0;
+ EmitFWrite(CI->getOperand(1),
+ ConstantInt::get(TD->getIntPtrType(*Context), Len-1),
+ CI->getOperand(2), B, TD);
+ return CI; // Known to have no uses (see above).
+ }
+};
+
+//===---------------------------------------===//
+// 'fprintf' Optimizations
+
+struct FPrintFOpt : public LibCallOptimization {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
+ // Require two fixed paramters as pointers and integer result.
+ const FunctionType *FT = Callee->getFunctionType();
+ if (FT->getNumParams() != 2 || !FT->getParamType(0)->isPointerTy() ||
+ !FT->getParamType(1)->isPointerTy() ||
+ !FT->getReturnType()->isIntegerTy())
+ return 0;
+
+ // All the optimizations depend on the format string.
+ std::string FormatStr;
+ if (!GetConstantStringInfo(CI->getOperand(2), FormatStr))
+ return 0;
+
+ // fprintf(F, "foo") --> fwrite("foo", 3, 1, F)
+ if (CI->getNumOperands() == 3) {
+ 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->getOperand(2),
+ ConstantInt::get(TD->getIntPtrType(*Context),
+ FormatStr.size()),
+ CI->getOperand(1), B, TD);
+ 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->getNumOperands() <4)
+ return 0;
+
+ // Decode the second character of the format string.
+ if (FormatStr[1] == 'c') {
+ // fprintf(F, "%c", chr) --> *(i8*)dst = chr
+ if (!CI->getOperand(3)->getType()->isIntegerTy()) return 0;
+ EmitFPutC(CI->getOperand(3), CI->getOperand(1), B, TD);
+ return ConstantInt::get(CI->getType(), 1);
+ }
+
+ if (FormatStr[1] == 's') {
+ // fprintf(F, "%s", str) -> fputs(str, F)
+ if (!CI->getOperand(3)->getType()->isPointerTy() || !CI->use_empty())
+ return 0;
+ EmitFPutS(CI->getOperand(3), CI->getOperand(1), B, TD);
+ return CI;
+ }
+ return 0;
+ }
+};
+
+} // end anonymous namespace.
+
+//===----------------------------------------------------------------------===//
+// SimplifyLibCalls Pass Implementation
+//===----------------------------------------------------------------------===//
+
+namespace {
+ /// This pass optimizes well known library functions from libc and libm.
+ ///
+ class SimplifyLibCalls : public FunctionPass {
+ StringMap<LibCallOptimization*> Optimizations;
+ // String and Memory LibCall Optimizations
+ StrCatOpt StrCat; StrNCatOpt StrNCat; StrChrOpt StrChr; StrCmpOpt StrCmp;
+ StrNCmpOpt StrNCmp; StrCpyOpt StrCpy; StrCpyOpt StrCpyChk;
+ StrNCpyOpt StrNCpy; StrLenOpt StrLen;
+ StrToOpt StrTo; StrStrOpt StrStr;
+ MemCmpOpt MemCmp; MemCpyOpt MemCpy; MemMoveOpt MemMove; MemSetOpt MemSet;
+ // Math Library Optimizations
+ 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;
+
+ bool Modified; // This is only used by doInitialization.
+ public:
+ static char ID; // Pass identification
+ SimplifyLibCalls() : FunctionPass(&ID), StrCpy(false), StrCpyChk(true) {}
+ 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);
+
+ virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+ }
+ };
+ char SimplifyLibCalls::ID = 0;
+} // end anonymous namespace.
+
+static RegisterPass<SimplifyLibCalls>
+X("simplify-libcalls", "Simplify well-known library calls");
+
+// Public interface to the Simplify LibCalls pass.
+FunctionPass *llvm::createSimplifyLibCallsPass() {
+ return new SimplifyLibCalls();
+}
+
+/// 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["strcmp"] = &StrCmp;
+ Optimizations["strncmp"] = &StrNCmp;
+ Optimizations["strcpy"] = &StrCpy;
+ Optimizations["strncpy"] = &StrNCpy;
+ Optimizations["strlen"] = &StrLen;
+ Optimizations["strtol"] = &StrTo;
+ Optimizations["strtod"] = &StrTo;
+ Optimizations["strtof"] = &StrTo;
+ Optimizations["strtoul"] = &StrTo;
+ Optimizations["strtoll"] = &StrTo;
+ Optimizations["strtold"] = &StrTo;
+ Optimizations["strtoull"] = &StrTo;
+ Optimizations["strstr"] = &StrStr;
+ Optimizations["memcmp"] = &MemCmp;
+ Optimizations["memcpy"] = &MemCpy;
+ Optimizations["memmove"] = &MemMove;
+ Optimizations["memset"] = &MemSet;
+
+ // _chk variants of String and Memory LibCall Optimizations.
+ Optimizations["__strcpy_chk"] = &StrCpyChk;
+
+ // Math Library Optimizations
+ 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;
+
+#ifdef HAVE_FLOORF
+ Optimizations["floor"] = &UnaryDoubleFP;
+#endif
+#ifdef HAVE_CEILF
+ Optimizations["ceil"] = &UnaryDoubleFP;
+#endif
+#ifdef HAVE_ROUNDF
+ Optimizations["round"] = &UnaryDoubleFP;
+#endif
+#ifdef HAVE_RINTF
+ Optimizations["rint"] = &UnaryDoubleFP;
+#endif
+#ifdef HAVE_NEARBYINTF
+ Optimizations["nearbyint"] = &UnaryDoubleFP;
+#endif
+
+ // 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;
+ Optimizations["fwrite"] = &FWrite;
+ Optimizations["fputs"] = &FPuts;
+ Optimizations["fprintf"] = &FPrintF;
+}
+
+
+/// runOnFunction - Top level algorithm.
+///
+bool SimplifyLibCalls::runOnFunction(Function &F) {
+ 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);
+
+ // Try to optimize this call.
+ Value *Result = LCO->OptimizeCall(CI, TD, 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;
+ }
+}
+
+/// 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())
+ continue;
+
+ if (!F.hasName())
+ continue;
+
+ const FunctionType *FTy = F.getFunctionType();
+
+ StringRef Name = F.getName();
+ switch (Name[0]) {
+ case 's':
+ if (Name == "strlen") {
+ if (FTy->getNumParams() != 1 ||
+ !FTy->getParamType(0)->isPointerTy())
+ continue;
+ 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())
+ continue;
+ 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 == "strtoull") {
+ if (FTy->getNumParams() < 2 ||
+ !FTy->getParamType(1)->isPointerTy())
+ continue;
+ setDoesNotThrow(F);
+ setDoesNotCapture(F, 2);
+ } else if (Name == "strxfrm") {
+ if (FTy->getNumParams() != 3 ||
+ !FTy->getParamType(0)->isPointerTy() ||
+ !FTy->getParamType(1)->isPointerTy())
+ continue;
+ 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())
+ continue;
+ setOnlyReadsMemory(F);
+ setDoesNotThrow(F);
+ setDoesNotCapture(F, 1);
+ setDoesNotCapture(F, 2);
+ } else if (Name == "strstr" ||
+ Name == "strpbrk") {
+ if (FTy->getNumParams() != 2 ||
+ !FTy->getParamType(1)->isPointerTy())
+ continue;
+ setOnlyReadsMemory(F);
+ setDoesNotThrow(F);
+ setDoesNotCapture(F, 2);
+ } else if (Name == "strtok" ||
+ Name == "strtok_r") {
+ if (FTy->getNumParams() < 2 ||
+ !FTy->getParamType(1)->isPointerTy())
+ continue;
+ setDoesNotThrow(F);
+ setDoesNotCapture(F, 2);
+ } else if (Name == "scanf" ||
+ Name == "setbuf" ||
+ Name == "setvbuf") {
+ if (FTy->getNumParams() < 1 ||
+ !FTy->getParamType(0)->isPointerTy())
+ continue;
+ setDoesNotThrow(F);
+ setDoesNotCapture(F, 1);
+ } else if (Name == "strdup" ||
+ Name == "strndup") {
+ if (FTy->getNumParams() < 1 ||
+ !FTy->getReturnType()->isPointerTy() ||
+ !FTy->getParamType(0)->isPointerTy())
+ continue;
+ 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())
+ continue;
+ setDoesNotThrow(F);
+ setDoesNotCapture(F, 1);
+ setDoesNotCapture(F, 2);
+ } else if (Name == "snprintf") {
+ if (FTy->getNumParams() != 3 ||
+ !FTy->getParamType(0)->isPointerTy() ||
+ !FTy->getParamType(2)->isPointerTy())
+ continue;
+ setDoesNotThrow(F);
+ setDoesNotCapture(F, 1);
+ setDoesNotCapture(F, 3);
+ } else if (Name == "setitimer") {
+ if (FTy->getNumParams() != 3 ||
+ !FTy->getParamType(1)->isPointerTy() ||
+ !FTy->getParamType(2)->isPointerTy())
+ continue;
+ setDoesNotThrow(F);
+ setDoesNotCapture(F, 2);
+ setDoesNotCapture(F, 3);
+ } else if (Name == "system") {
+ if (FTy->getNumParams() != 1 ||
+ !FTy->getParamType(0)->isPointerTy())
+ continue;
+ // 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())
+ continue;
+ setDoesNotThrow(F);
+ setDoesNotAlias(F, 0);
+ } else if (Name == "memcmp") {
+ if (FTy->getNumParams() != 3 ||
+ !FTy->getParamType(0)->isPointerTy() ||
+ !FTy->getParamType(1)->isPointerTy())
+ continue;
+ setOnlyReadsMemory(F);
+ setDoesNotThrow(F);
+ setDoesNotCapture(F, 1);
+ setDoesNotCapture(F, 2);
+ } else if (Name == "memchr" ||
+ Name == "memrchr") {
+ if (FTy->getNumParams() != 3)
+ continue;
+ 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())
+ continue;
+ setDoesNotThrow(F);
+ setDoesNotCapture(F, 2);
+ } else if (Name == "memalign") {
+ if (!FTy->getReturnType()->isPointerTy())
+ continue;
+ setDoesNotAlias(F, 0);
+ } else if (Name == "mkdir" ||
+ Name == "mktime") {
+ if (FTy->getNumParams() == 0 ||
+ !FTy->getParamType(0)->isPointerTy())
+ continue;
+ setDoesNotThrow(F);
+ setDoesNotCapture(F, 1);
+ }
+ break;
+ case 'r':
+ if (Name == "realloc") {
+ if (FTy->getNumParams() != 2 ||
+ !FTy->getParamType(0)->isPointerTy() ||
+ !FTy->getReturnType()->isPointerTy())
+ continue;
+ setDoesNotThrow(F);
+ setDoesNotAlias(F, 0);
+ setDoesNotCapture(F, 1);
+ } else if (Name == "read") {
+ if (FTy->getNumParams() != 3 ||
+ !FTy->getParamType(1)->isPointerTy())
+ continue;
+ // 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())
+ continue;
+ setDoesNotThrow(F);
+ setDoesNotCapture(F, 1);
+ } else if (Name == "rename" ||
+ Name == "readlink") {
+ if (FTy->getNumParams() < 2 ||
+ !FTy->getParamType(0)->isPointerTy() ||
+ !FTy->getParamType(1)->isPointerTy())
+ continue;
+ setDoesNotThrow(F);
+ setDoesNotCapture(F, 1);
+ setDoesNotCapture(F, 2);
+ }
+ break;
+ case 'w':
+ if (Name == "write") {
+ if (FTy->getNumParams() != 3 ||
+ !FTy->getParamType(1)->isPointerTy())
+ continue;
+ // 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())
+ continue;
+ setDoesNotThrow(F);
+ setDoesNotCapture(F, 1);
+ setDoesNotCapture(F, 2);
+ } else if (Name == "bcmp") {
+ if (FTy->getNumParams() != 3 ||
+ !FTy->getParamType(0)->isPointerTy() ||
+ !FTy->getParamType(1)->isPointerTy())
+ continue;
+ setDoesNotThrow(F);
+ setOnlyReadsMemory(F);
+ setDoesNotCapture(F, 1);
+ setDoesNotCapture(F, 2);
+ } else if (Name == "bzero") {
+ if (FTy->getNumParams() != 2 ||
+ !FTy->getParamType(0)->isPointerTy())
+ continue;
+ setDoesNotThrow(F);
+ setDoesNotCapture(F, 1);
+ }
+ break;
+ case 'c':
+ if (Name == "calloc") {
+ if (FTy->getNumParams() != 2 ||
+ !FTy->getReturnType()->isPointerTy())
+ continue;
+ 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())
+ continue;
+ 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())
+ continue;
+ setDoesNotThrow(F);
+ setOnlyReadsMemory(F);
+ setDoesNotCapture(F, 1);
+ } else if (Name == "access") {
+ if (FTy->getNumParams() != 2 ||
+ !FTy->getParamType(0)->isPointerTy())
+ continue;
+ 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())
+ continue;
+ 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())
+ continue;
+ 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())
+ continue;
+ setDoesNotThrow(F);
+ setDoesNotCapture(F, 1);
+ } else if (Name == "ferror") {
+ if (FTy->getNumParams() != 1 ||
+ !FTy->getParamType(0)->isPointerTy())
+ continue;
+ 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())
+ continue;
+ setDoesNotThrow(F);
+ setDoesNotCapture(F, 2);
+ } else if (Name == "fgets") {
+ if (FTy->getNumParams() != 3 ||
+ !FTy->getParamType(0)->isPointerTy() ||
+ !FTy->getParamType(2)->isPointerTy())
+ continue;
+ setDoesNotThrow(F);
+ setDoesNotCapture(F, 3);
+ } else if (Name == "fread" ||
+ Name == "fwrite") {
+ if (FTy->getNumParams() != 4 ||
+ !FTy->getParamType(0)->isPointerTy() ||
+ !FTy->getParamType(3)->isPointerTy())
+ continue;
+ 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())
+ continue;
+ 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())
+ continue;
+ setDoesNotThrow(F);
+ setDoesNotCapture(F, 1);
+ } else if (Name == "getenv") {
+ if (FTy->getNumParams() != 1 ||
+ !FTy->getParamType(0)->isPointerTy())
+ continue;
+ 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())
+ continue;
+ setDoesNotThrow(F);
+ setDoesNotCapture(F, 2);
+ } else if (Name == "getpwnam") {
+ if (FTy->getNumParams() != 1 ||
+ !FTy->getParamType(0)->isPointerTy())
+ continue;
+ setDoesNotThrow(F);
+ setDoesNotCapture(F, 1);
+ }
+ break;
+ case 'u':
+ if (Name == "ungetc") {
+ if (FTy->getNumParams() != 2 ||
+ !FTy->getParamType(1)->isPointerTy())
+ continue;
+ setDoesNotThrow(F);
+ setDoesNotCapture(F, 2);
+ } else if (Name == "uname" ||
+ Name == "unlink" ||
+ Name == "unsetenv") {
+ if (FTy->getNumParams() != 1 ||
+ !FTy->getParamType(0)->isPointerTy())
+ continue;
+ setDoesNotThrow(F);
+ setDoesNotCapture(F, 1);
+ } else if (Name == "utime" ||
+ Name == "utimes") {
+ if (FTy->getNumParams() != 2 ||
+ !FTy->getParamType(0)->isPointerTy() ||
+ !FTy->getParamType(1)->isPointerTy())
+ continue;
+ setDoesNotThrow(F);
+ setDoesNotCapture(F, 1);
+ setDoesNotCapture(F, 2);
+ }
+ break;
+ case 'p':
+ if (Name == "putc") {
+ if (FTy->getNumParams() != 2 ||
+ !FTy->getParamType(1)->isPointerTy())
+ continue;
+ setDoesNotThrow(F);
+ setDoesNotCapture(F, 2);
+ } else if (Name == "puts" ||
+ Name == "printf" ||
+ Name == "perror") {
+ if (FTy->getNumParams() != 1 ||
+ !FTy->getParamType(0)->isPointerTy())
+ continue;
+ setDoesNotThrow(F);
+ setDoesNotCapture(F, 1);
+ } else if (Name == "pread" ||
+ Name == "pwrite") {
+ if (FTy->getNumParams() != 4 ||
+ !FTy->getParamType(1)->isPointerTy())
+ continue;
+ // 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())
+ continue;
+ setDoesNotThrow(F);
+ setDoesNotAlias(F, 0);
+ setDoesNotCapture(F, 1);
+ setDoesNotCapture(F, 2);
+ } else if (Name == "pclose") {
+ if (FTy->getNumParams() != 1 ||
+ !FTy->getParamType(0)->isPointerTy())
+ continue;
+ setDoesNotThrow(F);
+ setDoesNotCapture(F, 1);
+ }
+ break;
+ case 'v':
+ if (Name == "vscanf") {
+ if (FTy->getNumParams() != 2 ||
+ !FTy->getParamType(1)->isPointerTy())
+ continue;
+ setDoesNotThrow(F);
+ setDoesNotCapture(F, 1);
+ } else if (Name == "vsscanf" ||
+ Name == "vfscanf") {
+ if (FTy->getNumParams() != 3 ||
+ !FTy->getParamType(1)->isPointerTy() ||
+ !FTy->getParamType(2)->isPointerTy())
+ continue;
+ setDoesNotThrow(F);
+ setDoesNotCapture(F, 1);
+ setDoesNotCapture(F, 2);
+ } else if (Name == "valloc") {
+ if (!FTy->getReturnType()->isPointerTy())
+ continue;
+ setDoesNotThrow(F);
+ setDoesNotAlias(F, 0);
+ } else if (Name == "vprintf") {
+ if (FTy->getNumParams() != 2 ||
+ !FTy->getParamType(0)->isPointerTy())
+ continue;
+ setDoesNotThrow(F);
+ setDoesNotCapture(F, 1);
+ } else if (Name == "vfprintf" ||
+ Name == "vsprintf") {
+ if (FTy->getNumParams() != 3 ||
+ !FTy->getParamType(0)->isPointerTy() ||
+ !FTy->getParamType(1)->isPointerTy())
+ continue;
+ setDoesNotThrow(F);
+ setDoesNotCapture(F, 1);
+ setDoesNotCapture(F, 2);
+ } else if (Name == "vsnprintf") {
+ if (FTy->getNumParams() != 4 ||
+ !FTy->getParamType(0)->isPointerTy() ||
+ !FTy->getParamType(2)->isPointerTy())
+ continue;
+ setDoesNotThrow(F);
+ setDoesNotCapture(F, 1);
+ setDoesNotCapture(F, 3);
+ }
+ break;
+ case 'o':
+ if (Name == "open") {
+ if (FTy->getNumParams() < 2 ||
+ !FTy->getParamType(0)->isPointerTy())
+ continue;
+ // 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())
+ continue;
+ setDoesNotThrow(F);
+ setDoesNotAlias(F, 0);
+ setDoesNotCapture(F, 1);
+ }
+ break;
+ case 't':
+ if (Name == "tmpfile") {
+ if (!FTy->getReturnType()->isPointerTy())
+ continue;
+ setDoesNotThrow(F);
+ setDoesNotAlias(F, 0);
+ } else if (Name == "times") {
+ if (FTy->getNumParams() != 1 ||
+ !FTy->getParamType(0)->isPointerTy())
+ continue;
+ 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())
+ continue;
+ setDoesNotThrow(F);
+ setDoesNotCapture(F, 1);
+ setDoesNotCapture(F, 2);
+ } else if (Name == "lchown") {
+ if (FTy->getNumParams() != 3 ||
+ !FTy->getParamType(0)->isPointerTy())
+ continue;
+ setDoesNotThrow(F);
+ setDoesNotCapture(F, 1);
+ }
+ break;
+ case 'q':
+ if (Name == "qsort") {
+ if (FTy->getNumParams() != 4 ||
+ !FTy->getParamType(3)->isPointerTy())
+ continue;
+ // 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())
+ continue;
+ setDoesNotThrow(F);
+ setDoesNotAlias(F, 0);
+ setDoesNotCapture(F, 1);
+ } else if (Name == "__strtok_r") {
+ if (FTy->getNumParams() != 3 ||
+ !FTy->getParamType(1)->isPointerTy())
+ continue;
+ setDoesNotThrow(F);
+ setDoesNotCapture(F, 2);
+ } else if (Name == "_IO_getc") {
+ if (FTy->getNumParams() != 1 ||
+ !FTy->getParamType(0)->isPointerTy())
+ continue;
+ setDoesNotThrow(F);
+ setDoesNotCapture(F, 1);
+ } else if (Name == "_IO_putc") {
+ if (FTy->getNumParams() != 2 ||
+ !FTy->getParamType(1)->isPointerTy())
+ continue;
+ setDoesNotThrow(F);
+ setDoesNotCapture(F, 2);
+ }
+ break;
+ case 1:
+ if (Name == "\1__isoc99_scanf") {
+ if (FTy->getNumParams() < 1 ||
+ !FTy->getParamType(0)->isPointerTy())
+ continue;
+ 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())
+ continue;
+ 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())
+ continue;
+ 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())
+ continue;
+ setDoesNotThrow(F);
+ setDoesNotCapture(F, 1);
+ } else if (Name == "\1tmpfile64") {
+ if (!FTy->getReturnType()->isPointerTy())
+ continue;
+ setDoesNotThrow(F);
+ setDoesNotAlias(F, 0);
+ } else if (Name == "\1fstat64" ||
+ Name == "\1fstatvfs64") {
+ if (FTy->getNumParams() != 2 ||
+ !FTy->getParamType(1)->isPointerTy())
+ continue;
+ setDoesNotThrow(F);
+ setDoesNotCapture(F, 2);
+ } else if (Name == "\1open64") {
+ if (FTy->getNumParams() < 2 ||
+ !FTy->getParamType(0)->isPointerTy())
+ continue;
+ // May throw; "open" is a valid pthread cancellation point.
+ setDoesNotCapture(F, 1);
+ }
+ break;
+ }
+ }
+ 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)
+//
+// cos, cosf, cosl:
+// * cos(-x) -> cos(x)
+//
+// 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)
+//
+// puts:
+// * puts("") -> putchar("\n")
+//
+// 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)
+//
+// stpcpy:
+// * stpcpy(str, "literal") ->
+// llvm.memcpy(str,"literal",strlen("literal")+1,1)
+// strrchr:
+// * strrchr(s,c) -> reverse_offset_of_in(c,s)
+// (if c is a constant integer and s is a constant string)
+// * strrchr(s1,0) -> strchr(s1,0)
+//
+// strpbrk:
+// * strpbrk(s,a) -> offset_in_for(s,a)
+// (if s and a are both constant strings)
+// * strpbrk(s,"") -> 0
+// * strpbrk(s,a) -> strchr(s,a[0]) (if a is constant string of length 1)
+//
+// strspn, strcspn:
+// * strspn(s,a) -> const_int (if both args are constant)
+// * strspn("",a) -> 0
+// * strspn(s,"") -> 0
+// * strcspn(s,a) -> const_int (if both args are constant)
+// * strcspn("",a) -> 0
+// * strcspn(s,"") -> strlen(a)
+//
+// tan, tanf, tanl:
+// * tan(atan(x)) -> x
+//
+// trunc, truncf, truncl:
+// * trunc(cnst) -> cnst'
+//
+//
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