1//===- SimplifyLibCalls.h - Library call simplifier -------------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file exposes an interface to build some C language libcalls for
10// optimization passes that need to call the various functions.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_TRANSFORMS_UTILS_SIMPLIFYLIBCALLS_H
15#define LLVM_TRANSFORMS_UTILS_SIMPLIFYLIBCALLS_H
16
17#include "llvm/ADT/STLFunctionalExtras.h"
18#include "llvm/Analysis/TargetLibraryInfo.h"
19
20namespace llvm {
21class AssumptionCache;
22class StringRef;
23class Value;
24class CallInst;
25class DataLayout;
26class Instruction;
27class IRBuilderBase;
28class Function;
29class OptimizationRemarkEmitter;
30class BlockFrequencyInfo;
31class ProfileSummaryInfo;
32
33/// This class implements simplifications for calls to fortified library
34/// functions (__st*cpy_chk, __memcpy_chk, __memmove_chk, __memset_chk), to,
35/// when possible, replace them with their non-checking counterparts.
36/// Other optimizations can also be done, but it's possible to disable them and
37/// only simplify needless use of the checking versions (when the object size
38/// is unknown) by passing true for OnlyLowerUnknownSize.
39class FortifiedLibCallSimplifier {
40private:
41 const TargetLibraryInfo *TLI;
42 bool OnlyLowerUnknownSize;
43
44public:
45 FortifiedLibCallSimplifier(const TargetLibraryInfo *TLI,
46 bool OnlyLowerUnknownSize = false);
47
48 /// Take the given call instruction and return a more
49 /// optimal value to replace the instruction with or 0 if a more
50 /// optimal form can't be found.
51 /// The call must not be an indirect call.
52 Value *optimizeCall(CallInst *CI, IRBuilderBase &B);
53
54private:
55 Value *optimizeMemCpyChk(CallInst *CI, IRBuilderBase &B);
56 Value *optimizeMemMoveChk(CallInst *CI, IRBuilderBase &B);
57 Value *optimizeMemSetChk(CallInst *CI, IRBuilderBase &B);
58
59 /// Str/Stp cpy are similar enough to be handled in the same functions.
60 Value *optimizeStrpCpyChk(CallInst *CI, IRBuilderBase &B, LibFunc Func);
61 Value *optimizeStrpNCpyChk(CallInst *CI, IRBuilderBase &B, LibFunc Func);
62 Value *optimizeStrLenChk(CallInst *CI, IRBuilderBase &B);
63 Value *optimizeMemPCpyChk(CallInst *CI, IRBuilderBase &B);
64 Value *optimizeMemCCpyChk(CallInst *CI, IRBuilderBase &B);
65 Value *optimizeSNPrintfChk(CallInst *CI, IRBuilderBase &B);
66 Value *optimizeSPrintfChk(CallInst *CI,IRBuilderBase &B);
67 Value *optimizeStrCatChk(CallInst *CI, IRBuilderBase &B);
68 Value *optimizeStrLCat(CallInst *CI, IRBuilderBase &B);
69 Value *optimizeStrNCatChk(CallInst *CI, IRBuilderBase &B);
70 Value *optimizeStrLCpyChk(CallInst *CI, IRBuilderBase &B);
71 Value *optimizeVSNPrintfChk(CallInst *CI, IRBuilderBase &B);
72 Value *optimizeVSPrintfChk(CallInst *CI, IRBuilderBase &B);
73
74 /// Checks whether the call \p CI to a fortified libcall is foldable
75 /// to the non-fortified version.
76 ///
77 /// \param CI the call to the fortified libcall.
78 ///
79 /// \param ObjSizeOp the index of the object size parameter of this chk
80 /// function. Not optional since this is mandatory.
81 ///
82 /// \param SizeOp optionally set to the parameter index of an explicit buffer
83 /// size argument. For instance, set to '2' for __strncpy_chk.
84 ///
85 /// \param StrOp optionally set to the parameter index of the source string
86 /// parameter to strcpy-like functions, where only the strlen of the source
87 /// will be writtin into the destination.
88 ///
89 /// \param FlagsOp optionally set to the parameter index of a 'flags'
90 /// parameter. These are used by an implementation to opt-into stricter
91 /// checking.
92 bool isFortifiedCallFoldable(CallInst *CI, unsigned ObjSizeOp,
93 std::optional<unsigned> SizeOp = std::nullopt,
94 std::optional<unsigned> StrOp = std::nullopt,
95 std::optional<unsigned> FlagsOp = std::nullopt);
96};
97
98/// LibCallSimplifier - This class implements a collection of optimizations
99/// that replace well formed calls to library functions with a more optimal
100/// form. For example, replacing 'printf("Hello!")' with 'puts("Hello!")'.
101class LibCallSimplifier {
102private:
103 FortifiedLibCallSimplifier FortifiedSimplifier;
104 const DataLayout &DL;
105 const TargetLibraryInfo *TLI;
106 AssumptionCache *AC;
107 OptimizationRemarkEmitter &ORE;
108 BlockFrequencyInfo *BFI;
109 ProfileSummaryInfo *PSI;
110 bool UnsafeFPShrink = false;
111 function_ref<void(Instruction *, Value *)> Replacer;
112 function_ref<void(Instruction *)> Eraser;
113
114 /// Internal wrapper for RAUW that is the default implementation.
115 ///
116 /// Other users may provide an alternate function with this signature instead
117 /// of this one.
118 static void replaceAllUsesWithDefault(Instruction *I, Value *With) {
119 I->replaceAllUsesWith(V: With);
120 }
121
122 /// Internal wrapper for eraseFromParent that is the default implementation.
123 static void eraseFromParentDefault(Instruction *I) { I->eraseFromParent(); }
124
125 /// Replace an instruction's uses with a value using our replacer.
126 void replaceAllUsesWith(Instruction *I, Value *With);
127
128 /// Erase an instruction from its parent with our eraser.
129 void eraseFromParent(Instruction *I);
130
131 /// Replace an instruction with a value and erase it from its parent.
132 void substituteInParent(Instruction *I, Value *With) {
133 replaceAllUsesWith(I, With);
134 eraseFromParent(I);
135 }
136
137public:
138 LibCallSimplifier(
139 const DataLayout &DL, const TargetLibraryInfo *TLI, AssumptionCache *AC,
140 OptimizationRemarkEmitter &ORE, BlockFrequencyInfo *BFI,
141 ProfileSummaryInfo *PSI,
142 function_ref<void(Instruction *, Value *)> Replacer =
143 &replaceAllUsesWithDefault,
144 function_ref<void(Instruction *)> Eraser = &eraseFromParentDefault);
145
146 /// optimizeCall - Take the given call instruction and return a more
147 /// optimal value to replace the instruction with or 0 if a more
148 /// optimal form can't be found. Note that the returned value may
149 /// be equal to the instruction being optimized. In this case all
150 /// other instructions that use the given instruction were modified
151 /// and the given instruction is dead.
152 /// The call must not be an indirect call.
153 Value *optimizeCall(CallInst *CI, IRBuilderBase &B);
154
155private:
156 // String and Memory Library Call Optimizations
157 Value *optimizeStrCat(CallInst *CI, IRBuilderBase &B);
158 Value *optimizeStrNCat(CallInst *CI, IRBuilderBase &B);
159 Value *optimizeStrChr(CallInst *CI, IRBuilderBase &B);
160 Value *optimizeStrRChr(CallInst *CI, IRBuilderBase &B);
161 Value *optimizeStrCmp(CallInst *CI, IRBuilderBase &B);
162 Value *optimizeStrNCmp(CallInst *CI, IRBuilderBase &B);
163 Value *optimizeStrNDup(CallInst *CI, IRBuilderBase &B);
164 Value *optimizeStrCpy(CallInst *CI, IRBuilderBase &B);
165 Value *optimizeStpCpy(CallInst *CI, IRBuilderBase &B);
166 Value *optimizeStrLCpy(CallInst *CI, IRBuilderBase &B);
167 Value *optimizeStrNCpy(CallInst *CI, IRBuilderBase &B);
168 Value *optimizeStrLen(CallInst *CI, IRBuilderBase &B);
169 Value *optimizeStrNLen(CallInst *CI, IRBuilderBase &B);
170 Value *optimizeStrPBrk(CallInst *CI, IRBuilderBase &B);
171 Value *optimizeStrTo(CallInst *CI, IRBuilderBase &B);
172 Value *optimizeStrSpn(CallInst *CI, IRBuilderBase &B);
173 Value *optimizeStrCSpn(CallInst *CI, IRBuilderBase &B);
174 Value *optimizeStrStr(CallInst *CI, IRBuilderBase &B);
175 Value *optimizeMemChr(CallInst *CI, IRBuilderBase &B);
176 Value *optimizeMemRChr(CallInst *CI, IRBuilderBase &B);
177 Value *optimizeMemCmp(CallInst *CI, IRBuilderBase &B);
178 Value *optimizeBCmp(CallInst *CI, IRBuilderBase &B);
179 Value *optimizeMemCmpBCmpCommon(CallInst *CI, IRBuilderBase &B);
180 Value *optimizeMemCCpy(CallInst *CI, IRBuilderBase &B);
181 Value *optimizeMemPCpy(CallInst *CI, IRBuilderBase &B);
182 Value *optimizeMemCpy(CallInst *CI, IRBuilderBase &B);
183 Value *optimizeMemMove(CallInst *CI, IRBuilderBase &B);
184 Value *optimizeMemSet(CallInst *CI, IRBuilderBase &B);
185 Value *optimizeRealloc(CallInst *CI, IRBuilderBase &B);
186 Value *optimizeNew(CallInst *CI, IRBuilderBase &B, LibFunc &Func);
187 Value *optimizeWcslen(CallInst *CI, IRBuilderBase &B);
188 Value *optimizeBCopy(CallInst *CI, IRBuilderBase &B);
189
190 // Helper to optimize stpncpy and strncpy.
191 Value *optimizeStringNCpy(CallInst *CI, bool RetEnd, IRBuilderBase &B);
192 // Wrapper for all String/Memory Library Call Optimizations
193 Value *optimizeStringMemoryLibCall(CallInst *CI, IRBuilderBase &B);
194
195 // Math Library Optimizations
196 Value *optimizeCAbs(CallInst *CI, IRBuilderBase &B);
197 Value *optimizePow(CallInst *CI, IRBuilderBase &B);
198 Value *replacePowWithExp(CallInst *Pow, IRBuilderBase &B);
199 Value *replacePowWithSqrt(CallInst *Pow, IRBuilderBase &B);
200 Value *optimizeExp2(CallInst *CI, IRBuilderBase &B);
201 Value *optimizeFMinFMax(CallInst *CI, IRBuilderBase &B);
202 Value *optimizeLog(CallInst *CI, IRBuilderBase &B);
203 Value *optimizeSqrt(CallInst *CI, IRBuilderBase &B);
204 Value *mergeSqrtToExp(CallInst *CI, IRBuilderBase &B);
205 Value *optimizeSinCosPi(CallInst *CI, bool IsSin, IRBuilderBase &B);
206 Value *optimizeTrigInversionPairs(CallInst *CI, IRBuilderBase &B);
207 Value *optimizeSymmetric(CallInst *CI, LibFunc Func, IRBuilderBase &B);
208 // Wrapper for all floating point library call optimizations
209 Value *optimizeFloatingPointLibCall(CallInst *CI, LibFunc Func,
210 IRBuilderBase &B);
211
212 // Integer Library Call Optimizations
213 Value *optimizeFFS(CallInst *CI, IRBuilderBase &B);
214 Value *optimizeFls(CallInst *CI, IRBuilderBase &B);
215 Value *optimizeAbs(CallInst *CI, IRBuilderBase &B);
216 Value *optimizeIsDigit(CallInst *CI, IRBuilderBase &B);
217 Value *optimizeIsAscii(CallInst *CI, IRBuilderBase &B);
218 Value *optimizeToAscii(CallInst *CI, IRBuilderBase &B);
219 Value *optimizeAtoi(CallInst *CI, IRBuilderBase &B);
220 Value *optimizeStrToInt(CallInst *CI, IRBuilderBase &B, bool AsSigned);
221
222 // Formatting and IO Library Call Optimizations
223 Value *optimizeErrorReporting(CallInst *CI, IRBuilderBase &B,
224 int StreamArg = -1);
225 Value *optimizePrintF(CallInst *CI, IRBuilderBase &B);
226 Value *optimizeSPrintF(CallInst *CI, IRBuilderBase &B);
227 Value *optimizeSnPrintF(CallInst *CI, IRBuilderBase &B);
228 Value *optimizeFPrintF(CallInst *CI, IRBuilderBase &B);
229 Value *optimizeFWrite(CallInst *CI, IRBuilderBase &B);
230 Value *optimizeFPuts(CallInst *CI, IRBuilderBase &B);
231 Value *optimizePuts(CallInst *CI, IRBuilderBase &B);
232
233 // Helper methods
234 Value* emitSnPrintfMemCpy(CallInst *CI, Value *StrArg, StringRef Str,
235 uint64_t N, IRBuilderBase &B);
236 Value *emitStrLenMemCpy(Value *Src, Value *Dst, uint64_t Len,
237 IRBuilderBase &B);
238 void classifyArgUse(Value *Val, Function *F, bool IsFloat,
239 SmallVectorImpl<CallInst *> &SinCalls,
240 SmallVectorImpl<CallInst *> &CosCalls,
241 SmallVectorImpl<CallInst *> &SinCosCalls);
242 Value *optimizePrintFString(CallInst *CI, IRBuilderBase &B);
243 Value *optimizeSPrintFString(CallInst *CI, IRBuilderBase &B);
244 Value *optimizeSnPrintFString(CallInst *CI, IRBuilderBase &B);
245 Value *optimizeFPrintFString(CallInst *CI, IRBuilderBase &B);
246
247 /// hasFloatVersion - Checks if there is a float version of the specified
248 /// function by checking for an existing function with name FuncName + f
249 bool hasFloatVersion(const Module *M, StringRef FuncName);
250
251 /// Shared code to optimize strlen+wcslen and strnlen+wcsnlen.
252 Value *optimizeStringLength(CallInst *CI, IRBuilderBase &B, unsigned CharSize,
253 Value *Bound = nullptr);
254};
255} // End llvm namespace
256
257#endif
258