//===- SimplifyLibCalls.h - Library call simplifier -------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file exposes an interface to build some C language libcalls for
// optimization passes that need to call the various functions.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_TRANSFORMS_UTILS_SIMPLIFYLIBCALLS_H
#define LLVM_TRANSFORMS_UTILS_SIMPLIFYLIBCALLS_H
#include "llvm/ADT/STLFunctionalExtras.h"
#include "llvm/Analysis/TargetLibraryInfo.h"
namespace llvm {
class StringRef;
class Value;
class CallInst;
class DataLayout;
class Instruction;
class IRBuilderBase;
class Function;
class OptimizationRemarkEmitter;
class BlockFrequencyInfo;
class ProfileSummaryInfo;
/// This class implements simplifications for calls to fortified library
/// functions (__st*cpy_chk, __memcpy_chk, __memmove_chk, __memset_chk), to,
/// when possible, replace them with their non-checking counterparts.
/// Other optimizations can also be done, but it's possible to disable them and
/// only simplify needless use of the checking versions (when the object size
/// is unknown) by passing true for OnlyLowerUnknownSize.
class FortifiedLibCallSimplifier {
private:
const TargetLibraryInfo *TLI;
bool OnlyLowerUnknownSize;
public:
FortifiedLibCallSimplifier(const TargetLibraryInfo *TLI,
bool OnlyLowerUnknownSize = false);
/// Take the given call instruction and return a more
/// optimal value to replace the instruction with or 0 if a more
/// optimal form can't be found.
/// The call must not be an indirect call.
Value *optimizeCall(CallInst *CI, IRBuilderBase &B);
private:
Value *optimizeMemCpyChk(CallInst *CI, IRBuilderBase &B);
Value *optimizeMemMoveChk(CallInst *CI, IRBuilderBase &B);
Value *optimizeMemSetChk(CallInst *CI, IRBuilderBase &B);
/// Str/Stp cpy are similar enough to be handled in the same functions.
Value *optimizeStrpCpyChk(CallInst *CI, IRBuilderBase &B, LibFunc Func);
Value *optimizeStrpNCpyChk(CallInst *CI, IRBuilderBase &B, LibFunc Func);
Value *optimizeStrLenChk(CallInst *CI, IRBuilderBase &B);
Value *optimizeMemPCpyChk(CallInst *CI, IRBuilderBase &B);
Value *optimizeMemCCpyChk(CallInst *CI, IRBuilderBase &B);
Value *optimizeSNPrintfChk(CallInst *CI, IRBuilderBase &B);
Value *optimizeSPrintfChk(CallInst *CI,IRBuilderBase &B);
Value *optimizeStrCatChk(CallInst *CI, IRBuilderBase &B);
Value *optimizeStrLCat(CallInst *CI, IRBuilderBase &B);
Value *optimizeStrNCatChk(CallInst *CI, IRBuilderBase &B);
Value *optimizeStrLCpyChk(CallInst *CI, IRBuilderBase &B);
Value *optimizeVSNPrintfChk(CallInst *CI, IRBuilderBase &B);
Value *optimizeVSPrintfChk(CallInst *CI, IRBuilderBase &B);
/// Checks whether the call \p CI to a fortified libcall is foldable
/// to the non-fortified version.
///
/// \param CI the call to the fortified libcall.
///
/// \param ObjSizeOp the index of the object size parameter of this chk
/// function. Not optional since this is mandatory.
///
/// \param SizeOp optionally set to the parameter index of an explicit buffer
/// size argument. For instance, set to '2' for __strncpy_chk.
///
/// \param StrOp optionally set to the parameter index of the source string
/// parameter to strcpy-like functions, where only the strlen of the source
/// will be writtin into the destination.
///
/// \param FlagsOp optionally set to the parameter index of a 'flags'
/// parameter. These are used by an implementation to opt-into stricter
/// checking.
bool isFortifiedCallFoldable(CallInst *CI, unsigned ObjSizeOp,
std::optional<unsigned> SizeOp = std::nullopt,
std::optional<unsigned> StrOp = std::nullopt,
std::optional<unsigned> FlagsOp = std::nullopt);
};
/// LibCallSimplifier - This class implements a collection of optimizations
/// that replace well formed calls to library functions with a more optimal
/// form. For example, replacing 'printf("Hello!")' with 'puts("Hello!")'.
class LibCallSimplifier {
private:
FortifiedLibCallSimplifier FortifiedSimplifier;
const DataLayout &DL;
const TargetLibraryInfo *TLI;
OptimizationRemarkEmitter &ORE;
BlockFrequencyInfo *BFI;
ProfileSummaryInfo *PSI;
bool UnsafeFPShrink = false;
function_ref<void(Instruction *, Value *)> Replacer;
function_ref<void(Instruction *)> Eraser;
/// Internal wrapper for RAUW that is the default implementation.
///
/// Other users may provide an alternate function with this signature instead
/// of this one.
static void replaceAllUsesWithDefault(Instruction *I, Value *With) {
I->replaceAllUsesWith(With);
}
/// Internal wrapper for eraseFromParent that is the default implementation.
static void eraseFromParentDefault(Instruction *I) { I->eraseFromParent(); }
/// Replace an instruction's uses with a value using our replacer.
void replaceAllUsesWith(Instruction *I, Value *With);
/// Erase an instruction from its parent with our eraser.
void eraseFromParent(Instruction *I);
/// Replace an instruction with a value and erase it from its parent.
void substituteInParent(Instruction *I, Value *With) {
replaceAllUsesWith(I, With);
eraseFromParent(I);
}
public:
LibCallSimplifier(
const DataLayout &DL, const TargetLibraryInfo *TLI,
OptimizationRemarkEmitter &ORE,
BlockFrequencyInfo *BFI, ProfileSummaryInfo *PSI,
function_ref<void(Instruction *, Value *)> Replacer =
&replaceAllUsesWithDefault,
function_ref<void(Instruction *)> Eraser = &eraseFromParentDefault);
/// optimizeCall - Take the given call instruction and return a more
/// optimal value to replace the instruction with or 0 if a more
/// optimal form can't be found. Note that the returned value may
/// be equal to the instruction being optimized. In this case all
/// other instructions that use the given instruction were modified
/// and the given instruction is dead.
/// The call must not be an indirect call.
Value *optimizeCall(CallInst *CI, IRBuilderBase &B);
private:
// String and Memory Library Call Optimizations
Value *optimizeStrCat(CallInst *CI, IRBuilderBase &B);
Value *optimizeStrNCat(CallInst *CI, IRBuilderBase &B);
Value *optimizeStrChr(CallInst *CI, IRBuilderBase &B);
Value *optimizeStrRChr(CallInst *CI, IRBuilderBase &B);
Value *optimizeStrCmp(CallInst *CI, IRBuilderBase &B);
Value *optimizeStrNCmp(CallInst *CI, IRBuilderBase &B);
Value *optimizeStrNDup(CallInst *CI, IRBuilderBase &B);
Value *optimizeStrCpy(CallInst *CI, IRBuilderBase &B);
Value *optimizeStpCpy(CallInst *CI, IRBuilderBase &B);
Value *optimizeStrLCpy(CallInst *CI, IRBuilderBase &B);
Value *optimizeStrNCpy(CallInst *CI, IRBuilderBase &B);
Value *optimizeStrLen(CallInst *CI, IRBuilderBase &B);
Value *optimizeStrNLen(CallInst *CI, IRBuilderBase &B);
Value *optimizeStrPBrk(CallInst *CI, IRBuilderBase &B);
Value *optimizeStrTo(CallInst *CI, IRBuilderBase &B);
Value *optimizeStrSpn(CallInst *CI, IRBuilderBase &B);
Value *optimizeStrCSpn(CallInst *CI, IRBuilderBase &B);
Value *optimizeStrStr(CallInst *CI, IRBuilderBase &B);
Value *optimizeMemChr(CallInst *CI, IRBuilderBase &B);
Value *optimizeMemRChr(CallInst *CI, IRBuilderBase &B);
Value *optimizeMemCmp(CallInst *CI, IRBuilderBase &B);
Value *optimizeBCmp(CallInst *CI, IRBuilderBase &B);
Value *optimizeMemCmpBCmpCommon(CallInst *CI, IRBuilderBase &B);
Value *optimizeMemCCpy(CallInst *CI, IRBuilderBase &B);
Value *optimizeMemPCpy(CallInst *CI, IRBuilderBase &B);
Value *optimizeMemCpy(CallInst *CI, IRBuilderBase &B);
Value *optimizeMemMove(CallInst *CI, IRBuilderBase &B);
Value *optimizeMemSet(CallInst *CI, IRBuilderBase &B);
Value *optimizeRealloc(CallInst *CI, IRBuilderBase &B);
Value *optimizeWcslen(CallInst *CI, IRBuilderBase &B);
Value *optimizeBCopy(CallInst *CI, IRBuilderBase &B);
// Helper to optimize stpncpy and strncpy.
Value *optimizeStringNCpy(CallInst *CI, bool RetEnd, IRBuilderBase &B);
// Wrapper for all String/Memory Library Call Optimizations
Value *optimizeStringMemoryLibCall(CallInst *CI, IRBuilderBase &B);
// Math Library Optimizations
Value *optimizeCAbs(CallInst *CI, IRBuilderBase &B);
Value *optimizePow(CallInst *CI, IRBuilderBase &B);
Value *replacePowWithExp(CallInst *Pow, IRBuilderBase &B);
Value *replacePowWithSqrt(CallInst *Pow, IRBuilderBase &B);
Value *optimizeExp2(CallInst *CI, IRBuilderBase &B);
Value *optimizeFMinFMax(CallInst *CI, IRBuilderBase &B);
Value *optimizeLog(CallInst *CI, IRBuilderBase &B);
Value *optimizeSqrt(CallInst *CI, IRBuilderBase &B);
Value *optimizeSinCosPi(CallInst *CI, IRBuilderBase &B);
Value *optimizeTan(CallInst *CI, IRBuilderBase &B);
// Wrapper for all floating point library call optimizations
Value *optimizeFloatingPointLibCall(CallInst *CI, LibFunc Func,
IRBuilderBase &B);
// Integer Library Call Optimizations
Value *optimizeFFS(CallInst *CI, IRBuilderBase &B);
Value *optimizeFls(CallInst *CI, IRBuilderBase &B);
Value *optimizeAbs(CallInst *CI, IRBuilderBase &B);
Value *optimizeIsDigit(CallInst *CI, IRBuilderBase &B);
Value *optimizeIsAscii(CallInst *CI, IRBuilderBase &B);
Value *optimizeToAscii(CallInst *CI, IRBuilderBase &B);
Value *optimizeAtoi(CallInst *CI, IRBuilderBase &B);
Value *optimizeStrToInt(CallInst *CI, IRBuilderBase &B, bool AsSigned);
// Formatting and IO Library Call Optimizations
Value *optimizeErrorReporting(CallInst *CI, IRBuilderBase &B,
int StreamArg = -1);
Value *optimizePrintF(CallInst *CI, IRBuilderBase &B);
Value *optimizeSPrintF(CallInst *CI, IRBuilderBase &B);
Value *optimizeSnPrintF(CallInst *CI, IRBuilderBase &B);
Value *optimizeFPrintF(CallInst *CI, IRBuilderBase &B);
Value *optimizeFWrite(CallInst *CI, IRBuilderBase &B);
Value *optimizeFPuts(CallInst *CI, IRBuilderBase &B);
Value *optimizePuts(CallInst *CI, IRBuilderBase &B);
// Helper methods
Value* emitSnPrintfMemCpy(CallInst *CI, Value *StrArg, StringRef Str,
uint64_t N, IRBuilderBase &B);
Value *emitStrLenMemCpy(Value *Src, Value *Dst, uint64_t Len,
IRBuilderBase &B);
void classifyArgUse(Value *Val, Function *F, bool IsFloat,
SmallVectorImpl<CallInst *> &SinCalls,
SmallVectorImpl<CallInst *> &CosCalls,
SmallVectorImpl<CallInst *> &SinCosCalls);
Value *optimizePrintFString(CallInst *CI, IRBuilderBase &B);
Value *optimizeSPrintFString(CallInst *CI, IRBuilderBase &B);
Value *optimizeSnPrintFString(CallInst *CI, IRBuilderBase &B);
Value *optimizeFPrintFString(CallInst *CI, IRBuilderBase &B);
/// hasFloatVersion - Checks if there is a float version of the specified
/// function by checking for an existing function with name FuncName + f
bool hasFloatVersion(const Module *M, StringRef FuncName);
/// Shared code to optimize strlen+wcslen and strnlen+wcsnlen.
Value *optimizeStringLength(CallInst *CI, IRBuilderBase &B, unsigned CharSize,
Value *Bound = nullptr);
};
} // End llvm namespace
#endif