1 //===- Cloning.h - Clone various parts of LLVM programs ---------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines various functions that are used to clone chunks of LLVM
11 // code for various purposes. This varies from copying whole modules into new
12 // modules, to cloning functions with different arguments, to inlining
13 // functions, to copying basic blocks to support loop unrolling or superblock
16 //===----------------------------------------------------------------------===//
18 #ifndef LLVM_TRANSFORMS_UTILS_CLONING_H
19 #define LLVM_TRANSFORMS_UTILS_CLONING_H
21 #include "llvm/ADT/SmallVector.h"
22 #include "llvm/ADT/Twine.h"
23 #include "llvm/IR/ValueHandle.h"
24 #include "llvm/IR/ValueMap.h"
25 #include "llvm/Transforms/Utils/ValueMapper.h"
47 class AssumptionCacheTracker;
49 /// CloneModule - Return an exact copy of the specified module
51 Module *CloneModule(const Module *M);
52 Module *CloneModule(const Module *M, ValueToValueMapTy &VMap);
54 /// ClonedCodeInfo - This struct can be used to capture information about code
55 /// being cloned, while it is being cloned.
56 struct ClonedCodeInfo {
57 /// ContainsCalls - This is set to true if the cloned code contains a normal
61 /// ContainsDynamicAllocas - This is set to true if the cloned code contains
62 /// a 'dynamic' alloca. Dynamic allocas are allocas that are either not in
63 /// the entry block or they are in the entry block but are not a constant
65 bool ContainsDynamicAllocas;
67 ClonedCodeInfo() : ContainsCalls(false), ContainsDynamicAllocas(false) {}
70 /// CloneBasicBlock - Return a copy of the specified basic block, but without
71 /// embedding the block into a particular function. The block returned is an
72 /// exact copy of the specified basic block, without any remapping having been
73 /// performed. Because of this, this is only suitable for applications where
74 /// the basic block will be inserted into the same function that it was cloned
75 /// from (loop unrolling would use this, for example).
77 /// Also, note that this function makes a direct copy of the basic block, and
78 /// can thus produce illegal LLVM code. In particular, it will copy any PHI
79 /// nodes from the original block, even though there are no predecessors for the
80 /// newly cloned block (thus, phi nodes will have to be updated). Also, this
81 /// block will branch to the old successors of the original block: these
82 /// successors will have to have any PHI nodes updated to account for the new
85 /// The correlation between instructions in the source and result basic blocks
86 /// is recorded in the VMap map.
88 /// If you have a particular suffix you'd like to use to add to any cloned
89 /// names, specify it as the optional third parameter.
91 /// If you would like the basic block to be auto-inserted into the end of a
92 /// function, you can specify it as the optional fourth parameter.
94 /// If you would like to collect additional information about the cloned
95 /// function, you can specify a ClonedCodeInfo object with the optional fifth
98 BasicBlock *CloneBasicBlock(const BasicBlock *BB, ValueToValueMapTy &VMap,
99 const Twine &NameSuffix = "", Function *F = nullptr,
100 ClonedCodeInfo *CodeInfo = nullptr);
102 /// CloneFunction - Return a copy of the specified function, but without
103 /// embedding the function into another module. Also, any references specified
104 /// in the VMap are changed to refer to their mapped value instead of the
105 /// original one. If any of the arguments to the function are in the VMap,
106 /// the arguments are deleted from the resultant function. The VMap is
107 /// updated to include mappings from all of the instructions and basicblocks in
108 /// the function from their old to new values. The final argument captures
109 /// information about the cloned code if non-null.
111 /// If ModuleLevelChanges is false, VMap contains no non-identity GlobalValue
112 /// mappings, and debug info metadata will not be cloned.
114 Function *CloneFunction(const Function *F, ValueToValueMapTy &VMap,
115 bool ModuleLevelChanges,
116 ClonedCodeInfo *CodeInfo = nullptr);
118 /// Clone OldFunc into NewFunc, transforming the old arguments into references
119 /// to VMap values. Note that if NewFunc already has basic blocks, the ones
120 /// cloned into it will be added to the end of the function. This function
121 /// fills in a list of return instructions, and can optionally remap types
122 /// and/or append the specified suffix to all values cloned.
124 /// If ModuleLevelChanges is false, VMap contains no non-identity GlobalValue
127 void CloneFunctionInto(Function *NewFunc, const Function *OldFunc,
128 ValueToValueMapTy &VMap, bool ModuleLevelChanges,
129 SmallVectorImpl<ReturnInst*> &Returns,
130 const char *NameSuffix = "",
131 ClonedCodeInfo *CodeInfo = nullptr,
132 ValueMapTypeRemapper *TypeMapper = nullptr,
133 ValueMaterializer *Materializer = nullptr);
135 /// A helper class used with CloneAndPruneIntoFromInst to change the default
136 /// behavior while instructions are being cloned.
137 class CloningDirector {
139 /// This enumeration describes the way CloneAndPruneIntoFromInst should
140 /// proceed after the CloningDirector has examined an instruction.
142 ///< Continue cloning the instruction (default behavior).
144 ///< Skip this instruction but continue cloning the current basic block.
146 ///< Skip this instruction and stop cloning the current basic block.
150 virtual ~CloningDirector() = default;
152 /// Subclasses must override this function to customize cloning behavior.
153 virtual CloningAction handleInstruction(ValueToValueMapTy &VMap,
154 const Instruction *Inst,
155 BasicBlock *NewBB) = 0;
157 virtual ValueMapTypeRemapper *getTypeRemapper() { return nullptr; }
158 virtual ValueMaterializer *getValueMaterializer() { return nullptr; }
161 void CloneAndPruneIntoFromInst(Function *NewFunc, const Function *OldFunc,
162 const Instruction *StartingInst,
163 ValueToValueMapTy &VMap, bool ModuleLevelChanges,
164 SmallVectorImpl<ReturnInst*> &Returns,
165 const char *NameSuffix = "",
166 ClonedCodeInfo *CodeInfo = nullptr,
167 const DataLayout *DL = nullptr,
168 CloningDirector *Director = nullptr);
171 /// CloneAndPruneFunctionInto - This works exactly like CloneFunctionInto,
172 /// except that it does some simple constant prop and DCE on the fly. The
173 /// effect of this is to copy significantly less code in cases where (for
174 /// example) a function call with constant arguments is inlined, and those
175 /// constant arguments cause a significant amount of code in the callee to be
176 /// dead. Since this doesn't produce an exactly copy of the input, it can't be
177 /// used for things like CloneFunction or CloneModule.
179 /// If ModuleLevelChanges is false, VMap contains no non-identity GlobalValue
182 void CloneAndPruneFunctionInto(Function *NewFunc, const Function *OldFunc,
183 ValueToValueMapTy &VMap, bool ModuleLevelChanges,
184 SmallVectorImpl<ReturnInst*> &Returns,
185 const char *NameSuffix = "",
186 ClonedCodeInfo *CodeInfo = nullptr,
187 const DataLayout *DL = nullptr,
188 Instruction *TheCall = nullptr);
190 /// InlineFunctionInfo - This class captures the data input to the
191 /// InlineFunction call, and records the auxiliary results produced by it.
192 class InlineFunctionInfo {
194 explicit InlineFunctionInfo(CallGraph *cg = nullptr,
195 const DataLayout *DL = nullptr,
196 AliasAnalysis *AA = nullptr,
197 AssumptionCacheTracker *ACT = nullptr)
198 : CG(cg), DL(DL), AA(AA), ACT(ACT) {}
200 /// CG - If non-null, InlineFunction will update the callgraph to reflect the
201 /// changes it makes.
203 const DataLayout *DL;
205 AssumptionCacheTracker *ACT;
207 /// StaticAllocas - InlineFunction fills this in with all static allocas that
208 /// get copied into the caller.
209 SmallVector<AllocaInst *, 4> StaticAllocas;
211 /// InlinedCalls - InlineFunction fills this in with callsites that were
212 /// inlined from the callee. This is only filled in if CG is non-null.
213 SmallVector<WeakVH, 8> InlinedCalls;
216 StaticAllocas.clear();
217 InlinedCalls.clear();
221 /// InlineFunction - This function inlines the called function into the basic
222 /// block of the caller. This returns false if it is not possible to inline
223 /// this call. The program is still in a well defined state if this occurs
226 /// Note that this only does one level of inlining. For example, if the
227 /// instruction 'call B' is inlined, and 'B' calls 'C', then the call to 'C' now
228 /// exists in the instruction stream. Similarly this will inline a recursive
229 /// function by one level.
231 bool InlineFunction(CallInst *C, InlineFunctionInfo &IFI,
232 bool InsertLifetime = true);
233 bool InlineFunction(InvokeInst *II, InlineFunctionInfo &IFI,
234 bool InsertLifetime = true);
235 bool InlineFunction(CallSite CS, InlineFunctionInfo &IFI,
236 bool InsertLifetime = true);
238 } // End llvm namespace