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/Analysis/AliasAnalysis.h"
24 #include "llvm/IR/ValueHandle.h"
25 #include "llvm/IR/ValueMap.h"
26 #include "llvm/Transforms/Utils/ValueMapper.h"
48 class AssumptionCacheTracker;
51 /// Return an exact copy of the specified module
53 std::unique_ptr<Module> CloneModule(const Module *M);
54 std::unique_ptr<Module> CloneModule(const Module *M, ValueToValueMapTy &VMap);
56 /// Return a copy of the specified module. The ShouldCloneDefinition function
57 /// controls whether a specific GlobalValue's definition is cloned. If the
58 /// function returns false, the module copy will contain an external reference
59 /// in place of the global definition.
60 std::unique_ptr<Module>
61 CloneModule(const Module *M, ValueToValueMapTy &VMap,
62 std::function<bool(const GlobalValue *)> ShouldCloneDefinition);
64 /// ClonedCodeInfo - This struct can be used to capture information about code
65 /// being cloned, while it is being cloned.
66 struct ClonedCodeInfo {
67 /// ContainsCalls - This is set to true if the cloned code contains a normal
71 /// ContainsDynamicAllocas - This is set to true if the cloned code contains
72 /// a 'dynamic' alloca. Dynamic allocas are allocas that are either not in
73 /// the entry block or they are in the entry block but are not a constant
75 bool ContainsDynamicAllocas;
77 /// All cloned call sites that have operand bundles attached are appended to
78 /// this vector. This vector may contain nulls or undefs if some of the
79 /// originally inserted callsites were DCE'ed after they were cloned.
80 std::vector<WeakVH> OperandBundleCallSites;
82 ClonedCodeInfo() : ContainsCalls(false), ContainsDynamicAllocas(false) {}
85 /// CloneBasicBlock - Return a copy of the specified basic block, but without
86 /// embedding the block into a particular function. The block returned is an
87 /// exact copy of the specified basic block, without any remapping having been
88 /// performed. Because of this, this is only suitable for applications where
89 /// the basic block will be inserted into the same function that it was cloned
90 /// from (loop unrolling would use this, for example).
92 /// Also, note that this function makes a direct copy of the basic block, and
93 /// can thus produce illegal LLVM code. In particular, it will copy any PHI
94 /// nodes from the original block, even though there are no predecessors for the
95 /// newly cloned block (thus, phi nodes will have to be updated). Also, this
96 /// block will branch to the old successors of the original block: these
97 /// successors will have to have any PHI nodes updated to account for the new
100 /// The correlation between instructions in the source and result basic blocks
101 /// is recorded in the VMap map.
103 /// If you have a particular suffix you'd like to use to add to any cloned
104 /// names, specify it as the optional third parameter.
106 /// If you would like the basic block to be auto-inserted into the end of a
107 /// function, you can specify it as the optional fourth parameter.
109 /// If you would like to collect additional information about the cloned
110 /// function, you can specify a ClonedCodeInfo object with the optional fifth
113 BasicBlock *CloneBasicBlock(const BasicBlock *BB, ValueToValueMapTy &VMap,
114 const Twine &NameSuffix = "", Function *F = nullptr,
115 ClonedCodeInfo *CodeInfo = nullptr);
117 /// CloneFunction - Return a copy of the specified function, but without
118 /// embedding the function into another module. Also, any references specified
119 /// in the VMap are changed to refer to their mapped value instead of the
120 /// original one. If any of the arguments to the function are in the VMap,
121 /// the arguments are deleted from the resultant function. The VMap is
122 /// updated to include mappings from all of the instructions and basicblocks in
123 /// the function from their old to new values. The final argument captures
124 /// information about the cloned code if non-null.
126 /// If ModuleLevelChanges is false, VMap contains no non-identity GlobalValue
127 /// mappings, and debug info metadata will not be cloned.
129 Function *CloneFunction(const Function *F, ValueToValueMapTy &VMap,
130 bool ModuleLevelChanges,
131 ClonedCodeInfo *CodeInfo = nullptr);
133 /// Clone OldFunc into NewFunc, transforming the old arguments into references
134 /// to VMap values. Note that if NewFunc already has basic blocks, the ones
135 /// cloned into it will be added to the end of the function. This function
136 /// fills in a list of return instructions, and can optionally remap types
137 /// and/or append the specified suffix to all values cloned.
139 /// If ModuleLevelChanges is false, VMap contains no non-identity GlobalValue
142 void CloneFunctionInto(Function *NewFunc, const Function *OldFunc,
143 ValueToValueMapTy &VMap, bool ModuleLevelChanges,
144 SmallVectorImpl<ReturnInst*> &Returns,
145 const char *NameSuffix = "",
146 ClonedCodeInfo *CodeInfo = nullptr,
147 ValueMapTypeRemapper *TypeMapper = nullptr,
148 ValueMaterializer *Materializer = nullptr);
150 /// A helper class used with CloneAndPruneIntoFromInst to change the default
151 /// behavior while instructions are being cloned.
152 class CloningDirector {
154 /// This enumeration describes the way CloneAndPruneIntoFromInst should
155 /// proceed after the CloningDirector has examined an instruction.
157 ///< Continue cloning the instruction (default behavior).
159 ///< Skip this instruction but continue cloning the current basic block.
161 ///< Skip this instruction and stop cloning the current basic block.
163 ///< Don't clone the terminator but clone the current block's successors.
167 virtual ~CloningDirector() {}
169 /// Subclasses must override this function to customize cloning behavior.
170 virtual CloningAction handleInstruction(ValueToValueMapTy &VMap,
171 const Instruction *Inst,
172 BasicBlock *NewBB) = 0;
174 virtual ValueMapTypeRemapper *getTypeRemapper() { return nullptr; }
175 virtual ValueMaterializer *getValueMaterializer() { return nullptr; }
178 void CloneAndPruneIntoFromInst(Function *NewFunc, const Function *OldFunc,
179 const Instruction *StartingInst,
180 ValueToValueMapTy &VMap, bool ModuleLevelChanges,
181 SmallVectorImpl<ReturnInst*> &Returns,
182 const char *NameSuffix = "",
183 ClonedCodeInfo *CodeInfo = nullptr,
184 CloningDirector *Director = nullptr);
187 /// CloneAndPruneFunctionInto - This works exactly like CloneFunctionInto,
188 /// except that it does some simple constant prop and DCE on the fly. The
189 /// effect of this is to copy significantly less code in cases where (for
190 /// example) a function call with constant arguments is inlined, and those
191 /// constant arguments cause a significant amount of code in the callee to be
192 /// dead. Since this doesn't produce an exactly copy of the input, it can't be
193 /// used for things like CloneFunction or CloneModule.
195 /// If ModuleLevelChanges is false, VMap contains no non-identity GlobalValue
198 void CloneAndPruneFunctionInto(Function *NewFunc, const Function *OldFunc,
199 ValueToValueMapTy &VMap, bool ModuleLevelChanges,
200 SmallVectorImpl<ReturnInst*> &Returns,
201 const char *NameSuffix = "",
202 ClonedCodeInfo *CodeInfo = nullptr,
203 Instruction *TheCall = nullptr);
205 /// InlineFunctionInfo - This class captures the data input to the
206 /// InlineFunction call, and records the auxiliary results produced by it.
207 class InlineFunctionInfo {
209 explicit InlineFunctionInfo(CallGraph *cg = nullptr,
210 AssumptionCacheTracker *ACT = nullptr)
211 : CG(cg), ACT(ACT) {}
213 /// CG - If non-null, InlineFunction will update the callgraph to reflect the
214 /// changes it makes.
216 AssumptionCacheTracker *ACT;
218 /// StaticAllocas - InlineFunction fills this in with all static allocas that
219 /// get copied into the caller.
220 SmallVector<AllocaInst *, 4> StaticAllocas;
222 /// InlinedCalls - InlineFunction fills this in with callsites that were
223 /// inlined from the callee. This is only filled in if CG is non-null.
224 SmallVector<WeakVH, 8> InlinedCalls;
227 StaticAllocas.clear();
228 InlinedCalls.clear();
232 /// InlineFunction - This function inlines the called function into the basic
233 /// block of the caller. This returns false if it is not possible to inline
234 /// this call. The program is still in a well defined state if this occurs
237 /// Note that this only does one level of inlining. For example, if the
238 /// instruction 'call B' is inlined, and 'B' calls 'C', then the call to 'C' now
239 /// exists in the instruction stream. Similarly this will inline a recursive
240 /// function by one level.
242 bool InlineFunction(CallInst *C, InlineFunctionInfo &IFI,
243 AAResults *CalleeAAR = nullptr, bool InsertLifetime = true);
244 bool InlineFunction(InvokeInst *II, InlineFunctionInfo &IFI,
245 AAResults *CalleeAAR = nullptr, bool InsertLifetime = true);
246 bool InlineFunction(CallSite CS, InlineFunctionInfo &IFI,
247 AAResults *CalleeAAR = nullptr, bool InsertLifetime = true);
249 /// \brief Clones a loop \p OrigLoop. Returns the loop and the blocks in \p
252 /// Updates LoopInfo and DominatorTree assuming the loop is dominated by block
253 /// \p LoopDomBB. Insert the new blocks before block specified in \p Before.
254 Loop *cloneLoopWithPreheader(BasicBlock *Before, BasicBlock *LoopDomBB,
255 Loop *OrigLoop, ValueToValueMapTy &VMap,
256 const Twine &NameSuffix, LoopInfo *LI,
258 SmallVectorImpl<BasicBlock *> &Blocks);
260 /// \brief Remaps instructions in \p Blocks using the mapping in \p VMap.
261 void remapInstructionsInBlocks(const SmallVectorImpl<BasicBlock *> &Blocks,
262 ValueToValueMapTy &VMap);
264 } // End llvm namespace