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/Analysis/AssumptionCache.h"
25 #include "llvm/IR/CallSite.h"
26 #include "llvm/IR/ValueHandle.h"
27 #include "llvm/Transforms/Utils/ValueMapper.h"
36 class BlockFrequencyInfo;
48 /// Return an exact copy of the specified module
50 std::unique_ptr<Module> CloneModule(const Module *M);
51 std::unique_ptr<Module> CloneModule(const Module *M, ValueToValueMapTy &VMap);
53 /// Return a copy of the specified module. The ShouldCloneDefinition function
54 /// controls whether a specific GlobalValue's definition is cloned. If the
55 /// function returns false, the module copy will contain an external reference
56 /// in place of the global definition.
57 std::unique_ptr<Module>
58 CloneModule(const Module *M, ValueToValueMapTy &VMap,
59 function_ref<bool(const GlobalValue *)> ShouldCloneDefinition);
61 /// ClonedCodeInfo - This struct can be used to capture information about code
62 /// being cloned, while it is being cloned.
63 struct ClonedCodeInfo {
64 /// ContainsCalls - This is set to true if the cloned code contains a normal
66 bool ContainsCalls = false;
68 /// ContainsDynamicAllocas - This is set to true if the cloned code contains
69 /// a 'dynamic' alloca. Dynamic allocas are allocas that are either not in
70 /// the entry block or they are in the entry block but are not a constant
72 bool ContainsDynamicAllocas = false;
74 /// All cloned call sites that have operand bundles attached are appended to
75 /// this vector. This vector may contain nulls or undefs if some of the
76 /// originally inserted callsites were DCE'ed after they were cloned.
77 std::vector<WeakTrackingVH> OperandBundleCallSites;
79 ClonedCodeInfo() = default;
82 /// CloneBasicBlock - Return a copy of the specified basic block, but without
83 /// embedding the block into a particular function. The block returned is an
84 /// exact copy of the specified basic block, without any remapping having been
85 /// performed. Because of this, this is only suitable for applications where
86 /// the basic block will be inserted into the same function that it was cloned
87 /// from (loop unrolling would use this, for example).
89 /// Also, note that this function makes a direct copy of the basic block, and
90 /// can thus produce illegal LLVM code. In particular, it will copy any PHI
91 /// nodes from the original block, even though there are no predecessors for the
92 /// newly cloned block (thus, phi nodes will have to be updated). Also, this
93 /// block will branch to the old successors of the original block: these
94 /// successors will have to have any PHI nodes updated to account for the new
97 /// The correlation between instructions in the source and result basic blocks
98 /// is recorded in the VMap map.
100 /// If you have a particular suffix you'd like to use to add to any cloned
101 /// names, specify it as the optional third parameter.
103 /// If you would like the basic block to be auto-inserted into the end of a
104 /// function, you can specify it as the optional fourth parameter.
106 /// If you would like to collect additional information about the cloned
107 /// function, you can specify a ClonedCodeInfo object with the optional fifth
110 BasicBlock *CloneBasicBlock(const BasicBlock *BB, ValueToValueMapTy &VMap,
111 const Twine &NameSuffix = "", Function *F = nullptr,
112 ClonedCodeInfo *CodeInfo = nullptr);
114 /// CloneFunction - Return a copy of the specified function and add it to that
115 /// function's module. Also, any references specified in the VMap are changed
116 /// to refer to their mapped value instead of the original one. If any of the
117 /// arguments to the function are in the VMap, the arguments are deleted from
118 /// the resultant function. The VMap is updated to include mappings from all of
119 /// the instructions and basicblocks in the function from their old to new
120 /// values. The final argument captures information about the cloned code if
123 /// VMap contains no non-identity GlobalValue mappings and debug info metadata
124 /// will not be cloned.
126 Function *CloneFunction(Function *F, ValueToValueMapTy &VMap,
127 ClonedCodeInfo *CodeInfo = nullptr);
129 /// Clone OldFunc into NewFunc, transforming the old arguments into references
130 /// to VMap values. Note that if NewFunc already has basic blocks, the ones
131 /// cloned into it will be added to the end of the function. This function
132 /// fills in a list of return instructions, and can optionally remap types
133 /// and/or append the specified suffix to all values cloned.
135 /// If ModuleLevelChanges is false, VMap contains no non-identity GlobalValue
138 void CloneFunctionInto(Function *NewFunc, const Function *OldFunc,
139 ValueToValueMapTy &VMap, bool ModuleLevelChanges,
140 SmallVectorImpl<ReturnInst*> &Returns,
141 const char *NameSuffix = "",
142 ClonedCodeInfo *CodeInfo = nullptr,
143 ValueMapTypeRemapper *TypeMapper = nullptr,
144 ValueMaterializer *Materializer = nullptr);
146 void CloneAndPruneIntoFromInst(Function *NewFunc, const Function *OldFunc,
147 const Instruction *StartingInst,
148 ValueToValueMapTy &VMap, bool ModuleLevelChanges,
149 SmallVectorImpl<ReturnInst *> &Returns,
150 const char *NameSuffix = "",
151 ClonedCodeInfo *CodeInfo = nullptr);
153 /// CloneAndPruneFunctionInto - This works exactly like CloneFunctionInto,
154 /// except that it does some simple constant prop and DCE on the fly. The
155 /// effect of this is to copy significantly less code in cases where (for
156 /// example) a function call with constant arguments is inlined, and those
157 /// constant arguments cause a significant amount of code in the callee to be
158 /// dead. Since this doesn't produce an exactly copy of the input, it can't be
159 /// used for things like CloneFunction or CloneModule.
161 /// If ModuleLevelChanges is false, VMap contains no non-identity GlobalValue
164 void CloneAndPruneFunctionInto(Function *NewFunc, const Function *OldFunc,
165 ValueToValueMapTy &VMap, bool ModuleLevelChanges,
166 SmallVectorImpl<ReturnInst*> &Returns,
167 const char *NameSuffix = "",
168 ClonedCodeInfo *CodeInfo = nullptr,
169 Instruction *TheCall = nullptr);
171 /// InlineFunctionInfo - This class captures the data input to the
172 /// InlineFunction call, and records the auxiliary results produced by it.
173 class InlineFunctionInfo {
175 explicit InlineFunctionInfo(CallGraph *cg = nullptr,
176 std::function<AssumptionCache &(Function &)>
177 *GetAssumptionCache = nullptr,
178 BlockFrequencyInfo *CallerBFI = nullptr,
179 BlockFrequencyInfo *CalleeBFI = nullptr)
180 : CG(cg), GetAssumptionCache(GetAssumptionCache), CallerBFI(CallerBFI),
181 CalleeBFI(CalleeBFI) {}
183 /// CG - If non-null, InlineFunction will update the callgraph to reflect the
184 /// changes it makes.
186 std::function<AssumptionCache &(Function &)> *GetAssumptionCache;
187 BlockFrequencyInfo *CallerBFI, *CalleeBFI;
189 /// StaticAllocas - InlineFunction fills this in with all static allocas that
190 /// get copied into the caller.
191 SmallVector<AllocaInst *, 4> StaticAllocas;
193 /// InlinedCalls - InlineFunction fills this in with callsites that were
194 /// inlined from the callee. This is only filled in if CG is non-null.
195 SmallVector<WeakTrackingVH, 8> InlinedCalls;
197 /// All of the new call sites inlined into the caller.
199 /// 'InlineFunction' fills this in by scanning the inlined instructions, and
200 /// only if CG is null. If CG is non-null, instead the value handle
201 /// `InlinedCalls` above is used.
202 SmallVector<CallSite, 8> InlinedCallSites;
205 StaticAllocas.clear();
206 InlinedCalls.clear();
207 InlinedCallSites.clear();
211 /// InlineFunction - This function inlines the called function into the basic
212 /// block of the caller. This returns false if it is not possible to inline
213 /// this call. The program is still in a well defined state if this occurs
216 /// Note that this only does one level of inlining. For example, if the
217 /// instruction 'call B' is inlined, and 'B' calls 'C', then the call to 'C' now
218 /// exists in the instruction stream. Similarly this will inline a recursive
219 /// function by one level.
221 /// Note that while this routine is allowed to cleanup and optimize the
222 /// *inlined* code to minimize the actual inserted code, it must not delete
223 /// code in the caller as users of this routine may have pointers to
224 /// instructions in the caller that need to remain stable.
225 bool InlineFunction(CallInst *C, InlineFunctionInfo &IFI,
226 AAResults *CalleeAAR = nullptr, bool InsertLifetime = true);
227 bool InlineFunction(InvokeInst *II, InlineFunctionInfo &IFI,
228 AAResults *CalleeAAR = nullptr, bool InsertLifetime = true);
229 bool InlineFunction(CallSite CS, InlineFunctionInfo &IFI,
230 AAResults *CalleeAAR = nullptr, bool InsertLifetime = true);
232 /// \brief Clones a loop \p OrigLoop. Returns the loop and the blocks in \p
235 /// Updates LoopInfo and DominatorTree assuming the loop is dominated by block
236 /// \p LoopDomBB. Insert the new blocks before block specified in \p Before.
237 /// Note: Only innermost loops are supported.
238 Loop *cloneLoopWithPreheader(BasicBlock *Before, BasicBlock *LoopDomBB,
239 Loop *OrigLoop, ValueToValueMapTy &VMap,
240 const Twine &NameSuffix, LoopInfo *LI,
242 SmallVectorImpl<BasicBlock *> &Blocks);
244 /// \brief Remaps instructions in \p Blocks using the mapping in \p VMap.
245 void remapInstructionsInBlocks(const SmallVectorImpl<BasicBlock *> &Blocks,
246 ValueToValueMapTy &VMap);
248 /// Split edge between BB and PredBB and duplicate all non-Phi instructions
249 /// from BB between its beginning and the StopAt instruction into the split
250 /// block. Phi nodes are not duplicated, but their uses are handled correctly:
251 /// we replace them with the uses of corresponding Phi inputs. ValueMapping
252 /// is used to map the original instructions from BB to their newly-created
253 /// copies. Returns the split block.
255 DuplicateInstructionsInSplitBetween(BasicBlock *BB, BasicBlock *PredBB,
257 ValueToValueMapTy &ValueMapping);
258 } // end namespace llvm
260 #endif // LLVM_TRANSFORMS_UTILS_CLONING_H