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;
50 /// CloneModule - Return an exact copy of the specified module
52 Module *CloneModule(const Module *M);
53 Module *CloneModule(const Module *M, ValueToValueMapTy &VMap);
55 /// ClonedCodeInfo - This struct can be used to capture information about code
56 /// being cloned, while it is being cloned.
57 struct ClonedCodeInfo {
58 /// ContainsCalls - This is set to true if the cloned code contains a normal
62 /// ContainsDynamicAllocas - This is set to true if the cloned code contains
63 /// a 'dynamic' alloca. Dynamic allocas are allocas that are either not in
64 /// the entry block or they are in the entry block but are not a constant
66 bool ContainsDynamicAllocas;
68 ClonedCodeInfo() : ContainsCalls(false), ContainsDynamicAllocas(false) {}
71 /// CloneBasicBlock - Return a copy of the specified basic block, but without
72 /// embedding the block into a particular function. The block returned is an
73 /// exact copy of the specified basic block, without any remapping having been
74 /// performed. Because of this, this is only suitable for applications where
75 /// the basic block will be inserted into the same function that it was cloned
76 /// from (loop unrolling would use this, for example).
78 /// Also, note that this function makes a direct copy of the basic block, and
79 /// can thus produce illegal LLVM code. In particular, it will copy any PHI
80 /// nodes from the original block, even though there are no predecessors for the
81 /// newly cloned block (thus, phi nodes will have to be updated). Also, this
82 /// block will branch to the old successors of the original block: these
83 /// successors will have to have any PHI nodes updated to account for the new
86 /// The correlation between instructions in the source and result basic blocks
87 /// is recorded in the VMap map.
89 /// If you have a particular suffix you'd like to use to add to any cloned
90 /// names, specify it as the optional third parameter.
92 /// If you would like the basic block to be auto-inserted into the end of a
93 /// function, you can specify it as the optional fourth parameter.
95 /// If you would like to collect additional information about the cloned
96 /// function, you can specify a ClonedCodeInfo object with the optional fifth
99 BasicBlock *CloneBasicBlock(const BasicBlock *BB, ValueToValueMapTy &VMap,
100 const Twine &NameSuffix = "", Function *F = nullptr,
101 ClonedCodeInfo *CodeInfo = nullptr);
103 /// CloneFunction - Return a copy of the specified function, but without
104 /// embedding the function into another module. Also, any references specified
105 /// in the VMap are changed to refer to their mapped value instead of the
106 /// original one. If any of the arguments to the function are in the VMap,
107 /// the arguments are deleted from the resultant function. The VMap is
108 /// updated to include mappings from all of the instructions and basicblocks in
109 /// the function from their old to new values. The final argument captures
110 /// information about the cloned code if non-null.
112 /// If ModuleLevelChanges is false, VMap contains no non-identity GlobalValue
113 /// mappings, and debug info metadata will not be cloned.
115 Function *CloneFunction(const Function *F, ValueToValueMapTy &VMap,
116 bool ModuleLevelChanges,
117 ClonedCodeInfo *CodeInfo = nullptr);
119 /// Clone OldFunc into NewFunc, transforming the old arguments into references
120 /// to VMap values. Note that if NewFunc already has basic blocks, the ones
121 /// cloned into it will be added to the end of the function. This function
122 /// fills in a list of return instructions, and can optionally remap types
123 /// and/or append the specified suffix to all values cloned.
125 /// If ModuleLevelChanges is false, VMap contains no non-identity GlobalValue
128 void CloneFunctionInto(Function *NewFunc, const Function *OldFunc,
129 ValueToValueMapTy &VMap, bool ModuleLevelChanges,
130 SmallVectorImpl<ReturnInst*> &Returns,
131 const char *NameSuffix = "",
132 ClonedCodeInfo *CodeInfo = nullptr,
133 ValueMapTypeRemapper *TypeMapper = nullptr,
134 ValueMaterializer *Materializer = nullptr);
136 /// A helper class used with CloneAndPruneIntoFromInst to change the default
137 /// behavior while instructions are being cloned.
138 class CloningDirector {
140 /// This enumeration describes the way CloneAndPruneIntoFromInst should
141 /// proceed after the CloningDirector has examined an instruction.
143 ///< Continue cloning the instruction (default behavior).
145 ///< Skip this instruction but continue cloning the current basic block.
147 ///< Skip this instruction and stop cloning the current basic block.
149 ///< Don't clone the terminator but clone the current block's successors.
153 virtual ~CloningDirector() {}
155 /// Subclasses must override this function to customize cloning behavior.
156 virtual CloningAction handleInstruction(ValueToValueMapTy &VMap,
157 const Instruction *Inst,
158 BasicBlock *NewBB) = 0;
160 virtual ValueMapTypeRemapper *getTypeRemapper() { return nullptr; }
161 virtual ValueMaterializer *getValueMaterializer() { return nullptr; }
164 void CloneAndPruneIntoFromInst(Function *NewFunc, const Function *OldFunc,
165 const Instruction *StartingInst,
166 ValueToValueMapTy &VMap, bool ModuleLevelChanges,
167 SmallVectorImpl<ReturnInst*> &Returns,
168 const char *NameSuffix = "",
169 ClonedCodeInfo *CodeInfo = nullptr,
170 CloningDirector *Director = nullptr);
173 /// CloneAndPruneFunctionInto - This works exactly like CloneFunctionInto,
174 /// except that it does some simple constant prop and DCE on the fly. The
175 /// effect of this is to copy significantly less code in cases where (for
176 /// example) a function call with constant arguments is inlined, and those
177 /// constant arguments cause a significant amount of code in the callee to be
178 /// dead. Since this doesn't produce an exactly copy of the input, it can't be
179 /// used for things like CloneFunction or CloneModule.
181 /// If ModuleLevelChanges is false, VMap contains no non-identity GlobalValue
184 void CloneAndPruneFunctionInto(Function *NewFunc, const Function *OldFunc,
185 ValueToValueMapTy &VMap, bool ModuleLevelChanges,
186 SmallVectorImpl<ReturnInst*> &Returns,
187 const char *NameSuffix = "",
188 ClonedCodeInfo *CodeInfo = nullptr,
189 Instruction *TheCall = nullptr);
191 /// InlineFunctionInfo - This class captures the data input to the
192 /// InlineFunction call, and records the auxiliary results produced by it.
193 class InlineFunctionInfo {
195 explicit InlineFunctionInfo(CallGraph *cg = nullptr,
196 AliasAnalysis *AA = nullptr,
197 AssumptionCacheTracker *ACT = nullptr)
198 : CG(cg), AA(AA), ACT(ACT) {}
200 /// CG - If non-null, InlineFunction will update the callgraph to reflect the
201 /// changes it makes.
204 AssumptionCacheTracker *ACT;
206 /// StaticAllocas - InlineFunction fills this in with all static allocas that
207 /// get copied into the caller.
208 SmallVector<AllocaInst *, 4> StaticAllocas;
210 /// InlinedCalls - InlineFunction fills this in with callsites that were
211 /// inlined from the callee. This is only filled in if CG is non-null.
212 SmallVector<WeakVH, 8> InlinedCalls;
215 StaticAllocas.clear();
216 InlinedCalls.clear();
220 /// InlineFunction - This function inlines the called function into the basic
221 /// block of the caller. This returns false if it is not possible to inline
222 /// this call. The program is still in a well defined state if this occurs
225 /// Note that this only does one level of inlining. For example, if the
226 /// instruction 'call B' is inlined, and 'B' calls 'C', then the call to 'C' now
227 /// exists in the instruction stream. Similarly this will inline a recursive
228 /// function by one level.
230 bool InlineFunction(CallInst *C, InlineFunctionInfo &IFI,
231 bool InsertLifetime = true);
232 bool InlineFunction(InvokeInst *II, InlineFunctionInfo &IFI,
233 bool InsertLifetime = true);
234 bool InlineFunction(CallSite CS, InlineFunctionInfo &IFI,
235 bool InsertLifetime = true);
237 /// \brief Clones a loop \p OrigLoop. Returns the loop and the blocks in \p
240 /// Updates LoopInfo and DominatorTree assuming the loop is dominated by block
241 /// \p LoopDomBB. Insert the new blocks before block specified in \p Before.
242 Loop *cloneLoopWithPreheader(BasicBlock *Before, BasicBlock *LoopDomBB,
243 Loop *OrigLoop, ValueToValueMapTy &VMap,
244 const Twine &NameSuffix, LoopInfo *LI,
246 SmallVectorImpl<BasicBlock *> &Blocks);
248 /// \brief Remaps instructions in \p Blocks using the mapping in \p VMap.
249 void remapInstructionsInBlocks(const SmallVectorImpl<BasicBlock *> &Blocks,
250 ValueToValueMapTy &VMap);
252 } // End llvm namespace