LLVM  8.0.0svn
SimplifyLibCalls.h
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1 //===- SimplifyLibCalls.h - Library call simplifier -------------*- C++ -*-===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file exposes an interface to build some C language libcalls for
11 // optimization passes that need to call the various functions.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #ifndef LLVM_TRANSFORMS_UTILS_SIMPLIFYLIBCALLS_H
16 #define LLVM_TRANSFORMS_UTILS_SIMPLIFYLIBCALLS_H
17 
18 #include "llvm/ADT/STLExtras.h"
20 #include "llvm/IR/IRBuilder.h"
21 
22 namespace llvm {
23 class StringRef;
24 class Value;
25 class CallInst;
26 class DataLayout;
27 class Instruction;
28 class TargetLibraryInfo;
29 class BasicBlock;
30 class Function;
31 class OptimizationRemarkEmitter;
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.
40 private:
41  const TargetLibraryInfo *TLI;
42  bool OnlyLowerUnknownSize;
43 
44 public:
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.
53 
54 private:
55  Value *optimizeMemCpyChk(CallInst *CI, IRBuilder<> &B);
56  Value *optimizeMemMoveChk(CallInst *CI, IRBuilder<> &B);
57  Value *optimizeMemSetChk(CallInst *CI, IRBuilder<> &B);
58 
59  // Str/Stp cpy are similar enough to be handled in the same functions.
60  Value *optimizeStrpCpyChk(CallInst *CI, IRBuilder<> &B, LibFunc Func);
61  Value *optimizeStrpNCpyChk(CallInst *CI, IRBuilder<> &B, LibFunc Func);
62 
63  /// Checks whether the call \p CI to a fortified libcall is foldable
64  /// to the non-fortified version.
65  bool isFortifiedCallFoldable(CallInst *CI, unsigned ObjSizeOp,
66  unsigned SizeOp, bool isString);
67 };
68 
69 /// LibCallSimplifier - This class implements a collection of optimizations
70 /// that replace well formed calls to library functions with a more optimal
71 /// form. For example, replacing 'printf("Hello!")' with 'puts("Hello!")'.
73 private:
74  FortifiedLibCallSimplifier FortifiedSimplifier;
75  const DataLayout &DL;
76  const TargetLibraryInfo *TLI;
78  bool UnsafeFPShrink;
81 
82  /// Internal wrapper for RAUW that is the default implementation.
83  ///
84  /// Other users may provide an alternate function with this signature instead
85  /// of this one.
86  static void replaceAllUsesWithDefault(Instruction *I, Value *With) {
87  I->replaceAllUsesWith(With);
88  }
89 
90  /// Internal wrapper for eraseFromParent that is the default implementation.
91  static void eraseFromParentDefault(Instruction *I) { I->eraseFromParent(); }
92 
93  /// Replace an instruction's uses with a value using our replacer.
94  void replaceAllUsesWith(Instruction *I, Value *With);
95 
96  /// Erase an instruction from its parent with our eraser.
97  void eraseFromParent(Instruction *I);
98 
99  Value *foldMallocMemset(CallInst *Memset, IRBuilder<> &B);
100 
101 public:
103  const DataLayout &DL, const TargetLibraryInfo *TLI,
105  function_ref<void(Instruction *, Value *)> Replacer =
106  &replaceAllUsesWithDefault,
107  function_ref<void(Instruction *)> Eraser = &eraseFromParentDefault);
108 
109  /// optimizeCall - Take the given call instruction and return a more
110  /// optimal value to replace the instruction with or 0 if a more
111  /// optimal form can't be found. Note that the returned value may
112  /// be equal to the instruction being optimized. In this case all
113  /// other instructions that use the given instruction were modified
114  /// and the given instruction is dead.
115  /// The call must not be an indirect call.
117 
118 private:
119  // String and Memory Library Call Optimizations
120  Value *optimizeStrCat(CallInst *CI, IRBuilder<> &B);
121  Value *optimizeStrNCat(CallInst *CI, IRBuilder<> &B);
122  Value *optimizeStrChr(CallInst *CI, IRBuilder<> &B);
123  Value *optimizeStrRChr(CallInst *CI, IRBuilder<> &B);
124  Value *optimizeStrCmp(CallInst *CI, IRBuilder<> &B);
125  Value *optimizeStrNCmp(CallInst *CI, IRBuilder<> &B);
126  Value *optimizeStrCpy(CallInst *CI, IRBuilder<> &B);
127  Value *optimizeStpCpy(CallInst *CI, IRBuilder<> &B);
128  Value *optimizeStrNCpy(CallInst *CI, IRBuilder<> &B);
129  Value *optimizeStrLen(CallInst *CI, IRBuilder<> &B);
130  Value *optimizeStrPBrk(CallInst *CI, IRBuilder<> &B);
131  Value *optimizeStrTo(CallInst *CI, IRBuilder<> &B);
132  Value *optimizeStrSpn(CallInst *CI, IRBuilder<> &B);
133  Value *optimizeStrCSpn(CallInst *CI, IRBuilder<> &B);
134  Value *optimizeStrStr(CallInst *CI, IRBuilder<> &B);
135  Value *optimizeMemChr(CallInst *CI, IRBuilder<> &B);
136  Value *optimizeMemCmp(CallInst *CI, IRBuilder<> &B);
137  Value *optimizeMemCpy(CallInst *CI, IRBuilder<> &B);
138  Value *optimizeMemMove(CallInst *CI, IRBuilder<> &B);
139  Value *optimizeMemSet(CallInst *CI, IRBuilder<> &B);
140  Value *optimizeRealloc(CallInst *CI, IRBuilder<> &B);
141  Value *optimizeWcslen(CallInst *CI, IRBuilder<> &B);
142  // Wrapper for all String/Memory Library Call Optimizations
143  Value *optimizeStringMemoryLibCall(CallInst *CI, IRBuilder<> &B);
144 
145  // Math Library Optimizations
146  Value *optimizeCAbs(CallInst *CI, IRBuilder<> &B);
147  Value *optimizePow(CallInst *CI, IRBuilder<> &B);
148  Value *replacePowWithExp(CallInst *Pow, IRBuilder<> &B);
149  Value *replacePowWithSqrt(CallInst *Pow, IRBuilder<> &B);
150  Value *optimizeExp2(CallInst *CI, IRBuilder<> &B);
151  Value *optimizeFMinFMax(CallInst *CI, IRBuilder<> &B);
152  Value *optimizeLog(CallInst *CI, IRBuilder<> &B);
153  Value *optimizeSqrt(CallInst *CI, IRBuilder<> &B);
154  Value *optimizeSinCosPi(CallInst *CI, IRBuilder<> &B);
155  Value *optimizeTan(CallInst *CI, IRBuilder<> &B);
156  // Wrapper for all floating point library call optimizations
157  Value *optimizeFloatingPointLibCall(CallInst *CI, LibFunc Func,
158  IRBuilder<> &B);
159 
160  // Integer Library Call Optimizations
161  Value *optimizeFFS(CallInst *CI, IRBuilder<> &B);
162  Value *optimizeFls(CallInst *CI, IRBuilder<> &B);
163  Value *optimizeAbs(CallInst *CI, IRBuilder<> &B);
164  Value *optimizeIsDigit(CallInst *CI, IRBuilder<> &B);
165  Value *optimizeIsAscii(CallInst *CI, IRBuilder<> &B);
166  Value *optimizeToAscii(CallInst *CI, IRBuilder<> &B);
167  Value *optimizeAtoi(CallInst *CI, IRBuilder<> &B);
168  Value *optimizeStrtol(CallInst *CI, IRBuilder<> &B);
169 
170  // Formatting and IO Library Call Optimizations
171  Value *optimizeErrorReporting(CallInst *CI, IRBuilder<> &B,
172  int StreamArg = -1);
173  Value *optimizePrintF(CallInst *CI, IRBuilder<> &B);
174  Value *optimizeSPrintF(CallInst *CI, IRBuilder<> &B);
175  Value *optimizeSnPrintF(CallInst *CI, IRBuilder<> &B);
176  Value *optimizeFPrintF(CallInst *CI, IRBuilder<> &B);
177  Value *optimizeFWrite(CallInst *CI, IRBuilder<> &B);
178  Value *optimizeFRead(CallInst *CI, IRBuilder<> &B);
179  Value *optimizeFPuts(CallInst *CI, IRBuilder<> &B);
180  Value *optimizeFGets(CallInst *CI, IRBuilder<> &B);
181  Value *optimizeFPutc(CallInst *CI, IRBuilder<> &B);
182  Value *optimizeFGetc(CallInst *CI, IRBuilder<> &B);
183  Value *optimizePuts(CallInst *CI, IRBuilder<> &B);
184 
185  // Helper methods
186  Value *emitStrLenMemCpy(Value *Src, Value *Dst, uint64_t Len, IRBuilder<> &B);
187  void classifyArgUse(Value *Val, Function *F, bool IsFloat,
188  SmallVectorImpl<CallInst *> &SinCalls,
189  SmallVectorImpl<CallInst *> &CosCalls,
190  SmallVectorImpl<CallInst *> &SinCosCalls);
191  Value *optimizePrintFString(CallInst *CI, IRBuilder<> &B);
192  Value *optimizeSPrintFString(CallInst *CI, IRBuilder<> &B);
193  Value *optimizeSnPrintFString(CallInst *CI, IRBuilder<> &B);
194  Value *optimizeFPrintFString(CallInst *CI, IRBuilder<> &B);
195 
196  /// hasFloatVersion - Checks if there is a float version of the specified
197  /// function by checking for an existing function with name FuncName + f
198  bool hasFloatVersion(StringRef FuncName);
199 
200  /// Shared code to optimize strlen+wcslen.
201  Value *optimizeStringLength(CallInst *CI, IRBuilder<> &B, unsigned CharSize);
202 };
203 } // End llvm namespace
204 
205 #endif
LibCallSimplifier - This class implements a collection of optimizations that replace well formed call...
SymbolTableList< Instruction >::iterator eraseFromParent()
This method unlinks &#39;this&#39; from the containing basic block and deletes it.
Definition: Instruction.cpp:68
A parsed version of the target data layout string in and methods for querying it. ...
Definition: DataLayout.h:111
This class represents lattice values for constants.
Definition: AllocatorList.h:24
Various leaf nodes.
Definition: ISDOpcodes.h:60
Value * optimizeCall(CallInst *CI)
Take the given call instruction and return a more optimal value to replace the instruction with or 0 ...
This class represents a function call, abstracting a target machine&#39;s calling convention.
An efficient, type-erasing, non-owning reference to a callable.
Definition: STLExtras.h:111
F(f)
FortifiedLibCallSimplifier(const TargetLibraryInfo *TLI, bool OnlyLowerUnknownSize=false)
This provides a uniform API for creating instructions and inserting them into a basic block: either a...
Definition: IRBuilder.h:743
void replaceAllUsesWith(Value *V)
Change all uses of this to point to a new Value.
Definition: Value.cpp:430
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.
static GCRegistry::Add< OcamlGC > B("ocaml", "ocaml 3.10-compatible GC")
Provides information about what library functions are available for the current target.
#define I(x, y, z)
Definition: MD5.cpp:58
LLVM Value Representation.
Definition: Value.h:73
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:49
The optimization diagnostic interface.