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/STLExtras.h"
18#include "llvm/Analysis/TargetLibraryInfo.h"
19
20namespace llvm {
21class StringRef;
22class Value;
23class CallInst;
24class DataLayout;
25class Instruction;
26class IRBuilderBase;
27class Function;
28class OptimizationRemarkEmitter;
29class BlockFrequencyInfo;
30class ProfileSummaryInfo;
31
32/// This class implements simplifications for calls to fortified library
33/// functions (__st*cpy_chk, __memcpy_chk, __memmove_chk, __memset_chk), to,
34/// when possible, replace them with their non-checking counterparts.
35/// Other optimizations can also be done, but it's possible to disable them and
36/// only simplify needless use of the checking versions (when the object size
37/// is unknown) by passing true for OnlyLowerUnknownSize.
38class FortifiedLibCallSimplifier {
39private:
40 const TargetLibraryInfo *TLI;
41 bool OnlyLowerUnknownSize;
42
43public:
44 FortifiedLibCallSimplifier(const TargetLibraryInfo *TLI,
45 bool OnlyLowerUnknownSize = false);
46
47 /// Take the given call instruction and return a more
48 /// optimal value to replace the instruction with or 0 if a more
49 /// optimal form can't be found.
50 /// The call must not be an indirect call.
51 Value *optimizeCall(CallInst *CI, IRBuilderBase &B);
52
53private:
54 Value *optimizeMemCpyChk(CallInst *CI, IRBuilderBase &B);
55 Value *optimizeMemMoveChk(CallInst *CI, IRBuilderBase &B);
56 Value *optimizeMemSetChk(CallInst *CI, IRBuilderBase &B);
57
58 /// Str/Stp cpy are similar enough to be handled in the same functions.
59 Value *optimizeStrpCpyChk(CallInst *CI, IRBuilderBase &B, LibFunc Func);
60 Value *optimizeStrpNCpyChk(CallInst *CI, IRBuilderBase &B, LibFunc Func);
61 Value *optimizeStrLenChk(CallInst *CI, IRBuilderBase &B);
62 Value *optimizeMemPCpyChk(CallInst *CI, IRBuilderBase &B);
63 Value *optimizeMemCCpyChk(CallInst *CI, IRBuilderBase &B);
64 Value *optimizeSNPrintfChk(CallInst *CI, IRBuilderBase &B);
65 Value *optimizeSPrintfChk(CallInst *CI,IRBuilderBase &B);
66 Value *optimizeStrCatChk(CallInst *CI, IRBuilderBase &B);
67 Value *optimizeStrLCat(CallInst *CI, IRBuilderBase &B);
68 Value *optimizeStrNCatChk(CallInst *CI, IRBuilderBase &B);
69 Value *optimizeStrLCpyChk(CallInst *CI, IRBuilderBase &B);
70 Value *optimizeVSNPrintfChk(CallInst *CI, IRBuilderBase &B);
71 Value *optimizeVSPrintfChk(CallInst *CI, IRBuilderBase &B);
72
73 /// Checks whether the call \p CI to a fortified libcall is foldable
74 /// to the non-fortified version.
75 ///
76 /// \param CI the call to the fortified libcall.
77 ///
78 /// \param ObjSizeOp the index of the object size parameter of this chk
79 /// function. Not optional since this is mandatory.
80 ///
81 /// \param SizeOp optionally set to the parameter index of an explicit buffer
82 /// size argument. For instance, set to '2' for __strncpy_chk.
83 ///
84 /// \param StrOp optionally set to the parameter index of the source string
85 /// parameter to strcpy-like functions, where only the strlen of the source
86 /// will be writtin into the destination.
87 ///
88 /// \param FlagsOp optionally set to the parameter index of a 'flags'
89 /// parameter. These are used by an implementation to opt-into stricter
90 /// checking.
91 bool isFortifiedCallFoldable(CallInst *CI, unsigned ObjSizeOp,
92 Optional<unsigned> SizeOp = None,
93 Optional<unsigned> StrOp = None,
94 Optional<unsigned> FlagsOp = None);
95};
96
97/// LibCallSimplifier - This class implements a collection of optimizations
98/// that replace well formed calls to library functions with a more optimal
99/// form. For example, replacing 'printf("Hello!")' with 'puts("Hello!")'.
100class LibCallSimplifier {
101private:
102 FortifiedLibCallSimplifier FortifiedSimplifier;
103 const DataLayout &DL;
104 const TargetLibraryInfo *TLI;
105 OptimizationRemarkEmitter &ORE;
106 BlockFrequencyInfo *BFI;
107 ProfileSummaryInfo *PSI;
108 bool UnsafeFPShrink;
109 function_ref<void(Instruction *, Value *)> Replacer;
110 function_ref<void(Instruction *)> Eraser;
111
112 /// Internal wrapper for RAUW that is the default implementation.
113 ///
114 /// Other users may provide an alternate function with this signature instead
115 /// of this one.
116 static void replaceAllUsesWithDefault(Instruction *I, Value *With) {
117 I->replaceAllUsesWith(With);
118 }
119
120 /// Internal wrapper for eraseFromParent that is the default implementation.
121 static void eraseFromParentDefault(Instruction *I) { I->eraseFromParent(); }
122
123 /// Replace an instruction's uses with a value using our replacer.
124 void replaceAllUsesWith(Instruction *I, Value *With);
125
126 /// Erase an instruction from its parent with our eraser.
127 void eraseFromParent(Instruction *I);
128
129 /// Replace an instruction with a value and erase it from its parent.
130 void substituteInParent(Instruction *I, Value *With) {
131 replaceAllUsesWith(I, With);
132 eraseFromParent(I);
133 }
134
135 Value *foldMallocMemset(CallInst *Memset, IRBuilderBase &B);
136
137public:
138 LibCallSimplifier(
139 const DataLayout &DL, const TargetLibraryInfo *TLI,
140 OptimizationRemarkEmitter &ORE,
141 BlockFrequencyInfo *BFI, 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 *optimizeStrNCpy(CallInst *CI, IRBuilderBase &B);
167 Value *optimizeStrLen(CallInst *CI, IRBuilderBase &B);
168 Value *optimizeStrPBrk(CallInst *CI, IRBuilderBase &B);
169 Value *optimizeStrTo(CallInst *CI, IRBuilderBase &B);
170 Value *optimizeStrSpn(CallInst *CI, IRBuilderBase &B);
171 Value *optimizeStrCSpn(CallInst *CI, IRBuilderBase &B);
172 Value *optimizeStrStr(CallInst *CI, IRBuilderBase &B);
173 Value *optimizeMemChr(CallInst *CI, IRBuilderBase &B);
174 Value *optimizeMemRChr(CallInst *CI, IRBuilderBase &B);
175 Value *optimizeMemCmp(CallInst *CI, IRBuilderBase &B);
176 Value *optimizeBCmp(CallInst *CI, IRBuilderBase &B);
177 Value *optimizeMemCmpBCmpCommon(CallInst *CI, IRBuilderBase &B);
178 Value *optimizeMemCCpy(CallInst *CI, IRBuilderBase &B);
179 Value *optimizeMemPCpy(CallInst *CI, IRBuilderBase &B);
180 Value *optimizeMemCpy(CallInst *CI, IRBuilderBase &B);
181 Value *optimizeMemMove(CallInst *CI, IRBuilderBase &B);
182 Value *optimizeMemSet(CallInst *CI, IRBuilderBase &B);
183 Value *optimizeRealloc(CallInst *CI, IRBuilderBase &B);
184 Value *optimizeWcslen(CallInst *CI, IRBuilderBase &B);
185 Value *optimizeBCopy(CallInst *CI, IRBuilderBase &B);
186 // Wrapper for all String/Memory Library Call Optimizations
187 Value *optimizeStringMemoryLibCall(CallInst *CI, IRBuilderBase &B);
188
189 // Math Library Optimizations
190 Value *optimizeCAbs(CallInst *CI, IRBuilderBase &B);
191 Value *optimizePow(CallInst *CI, IRBuilderBase &B);
192 Value *replacePowWithExp(CallInst *Pow, IRBuilderBase &B);
193 Value *replacePowWithSqrt(CallInst *Pow, IRBuilderBase &B);
194 Value *optimizeExp2(CallInst *CI, IRBuilderBase &B);
195 Value *optimizeFMinFMax(CallInst *CI, IRBuilderBase &B);
196 Value *optimizeLog(CallInst *CI, IRBuilderBase &B);
197 Value *optimizeSqrt(CallInst *CI, IRBuilderBase &B);
198 Value *optimizeSinCosPi(CallInst *CI, IRBuilderBase &B);
199 Value *optimizeTan(CallInst *CI, IRBuilderBase &B);
200 // Wrapper for all floating point library call optimizations
201 Value *optimizeFloatingPointLibCall(CallInst *CI, LibFunc Func,
202 IRBuilderBase &B);
203
204 // Integer Library Call Optimizations
205 Value *optimizeFFS(CallInst *CI, IRBuilderBase &B);
206 Value *optimizeFls(CallInst *CI, IRBuilderBase &B);
207 Value *optimizeAbs(CallInst *CI, IRBuilderBase &B);
208 Value *optimizeIsDigit(CallInst *CI, IRBuilderBase &B);
209 Value *optimizeIsAscii(CallInst *CI, IRBuilderBase &B);
210 Value *optimizeToAscii(CallInst *CI, IRBuilderBase &B);
211 Value *optimizeAtoi(CallInst *CI, IRBuilderBase &B);
212 Value *optimizeStrtol(CallInst *CI, IRBuilderBase &B);
213
214 // Formatting and IO Library Call Optimizations
215 Value *optimizeErrorReporting(CallInst *CI, IRBuilderBase &B,
216 int StreamArg = -1);
217 Value *optimizePrintF(CallInst *CI, IRBuilderBase &B);
218 Value *optimizeSPrintF(CallInst *CI, IRBuilderBase &B);
219 Value *optimizeSnPrintF(CallInst *CI, IRBuilderBase &B);
220 Value *optimizeFPrintF(CallInst *CI, IRBuilderBase &B);
221 Value *optimizeFWrite(CallInst *CI, IRBuilderBase &B);
222 Value *optimizeFPuts(CallInst *CI, IRBuilderBase &B);
223 Value *optimizePuts(CallInst *CI, IRBuilderBase &B);
224
225 // Helper methods
226 Value *emitStrLenMemCpy(Value *Src, Value *Dst, uint64_t Len,
227 IRBuilderBase &B);
228 void classifyArgUse(Value *Val, Function *F, bool IsFloat,
229 SmallVectorImpl<CallInst *> &SinCalls,
230 SmallVectorImpl<CallInst *> &CosCalls,
231 SmallVectorImpl<CallInst *> &SinCosCalls);
232 Value *optimizePrintFString(CallInst *CI, IRBuilderBase &B);
233 Value *optimizeSPrintFString(CallInst *CI, IRBuilderBase &B);
234 Value *optimizeSnPrintFString(CallInst *CI, IRBuilderBase &B);
235 Value *optimizeFPrintFString(CallInst *CI, IRBuilderBase &B);
236
237 /// hasFloatVersion - Checks if there is a float version of the specified
238 /// function by checking for an existing function with name FuncName + f
239 bool hasFloatVersion(StringRef FuncName);
240
241 /// Shared code to optimize strlen+wcslen.
242 Value *optimizeStringLength(CallInst *CI, IRBuilderBase &B, unsigned CharSize);
243};
244} // End llvm namespace
245
246#endif
247