/Users/buildslave/jenkins/workspace/clang-stage2-coverage-R/llvm/include/llvm/Transforms/Utils/Cloning.h
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1 | | //===- Cloning.h - Clone various parts of LLVM programs ---------*- C++ -*-===// |
2 | | // |
3 | | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
4 | | // See https://llvm.org/LICENSE.txt for license information. |
5 | | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
6 | | // |
7 | | //===----------------------------------------------------------------------===// |
8 | | // |
9 | | // This file defines various functions that are used to clone chunks of LLVM |
10 | | // code for various purposes. This varies from copying whole modules into new |
11 | | // modules, to cloning functions with different arguments, to inlining |
12 | | // functions, to copying basic blocks to support loop unrolling or superblock |
13 | | // formation, etc. |
14 | | // |
15 | | //===----------------------------------------------------------------------===// |
16 | | |
17 | | #ifndef LLVM_TRANSFORMS_UTILS_CLONING_H |
18 | | #define LLVM_TRANSFORMS_UTILS_CLONING_H |
19 | | |
20 | | #include "llvm/ADT/SmallVector.h" |
21 | | #include "llvm/ADT/Twine.h" |
22 | | #include "llvm/Analysis/AliasAnalysis.h" |
23 | | #include "llvm/Analysis/AssumptionCache.h" |
24 | | #include "llvm/Analysis/InlineCost.h" |
25 | | #include "llvm/IR/CallSite.h" |
26 | | #include "llvm/IR/ValueHandle.h" |
27 | | #include "llvm/Transforms/Utils/ValueMapper.h" |
28 | | #include <functional> |
29 | | #include <memory> |
30 | | #include <vector> |
31 | | |
32 | | namespace llvm { |
33 | | |
34 | | class AllocaInst; |
35 | | class BasicBlock; |
36 | | class BlockFrequencyInfo; |
37 | | class CallInst; |
38 | | class CallGraph; |
39 | | class DebugInfoFinder; |
40 | | class DominatorTree; |
41 | | class Function; |
42 | | class Instruction; |
43 | | class InvokeInst; |
44 | | class Loop; |
45 | | class LoopInfo; |
46 | | class Module; |
47 | | class ProfileSummaryInfo; |
48 | | class ReturnInst; |
49 | | class DomTreeUpdater; |
50 | | |
51 | | /// Return an exact copy of the specified module |
52 | | std::unique_ptr<Module> CloneModule(const Module &M); |
53 | | std::unique_ptr<Module> CloneModule(const Module &M, ValueToValueMapTy &VMap); |
54 | | |
55 | | /// Return a copy of the specified module. The ShouldCloneDefinition function |
56 | | /// controls whether a specific GlobalValue's definition is cloned. If the |
57 | | /// function returns false, the module copy will contain an external reference |
58 | | /// in place of the global definition. |
59 | | std::unique_ptr<Module> |
60 | | CloneModule(const Module &M, ValueToValueMapTy &VMap, |
61 | | function_ref<bool(const GlobalValue *)> ShouldCloneDefinition); |
62 | | |
63 | | /// This struct can be used to capture information about code |
64 | | /// being cloned, while it is being cloned. |
65 | | struct ClonedCodeInfo { |
66 | | /// This is set to true if the cloned code contains a normal call instruction. |
67 | | bool ContainsCalls = false; |
68 | | |
69 | | /// This is set to true if the cloned code contains a 'dynamic' alloca. |
70 | | /// Dynamic allocas are allocas that are either not in the entry block or they |
71 | | /// are in the entry block but are not a constant size. |
72 | | bool ContainsDynamicAllocas = false; |
73 | | |
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; |
78 | | |
79 | 541k | ClonedCodeInfo() = default; |
80 | | }; |
81 | | |
82 | | /// 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). |
88 | | /// |
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 |
95 | | /// incoming edges. |
96 | | /// |
97 | | /// The correlation between instructions in the source and result basic blocks |
98 | | /// is recorded in the VMap map. |
99 | | /// |
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. |
102 | | /// |
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. |
105 | | /// |
106 | | /// If you would like to collect additional information about the cloned |
107 | | /// function, you can specify a ClonedCodeInfo object with the optional fifth |
108 | | /// parameter. |
109 | | BasicBlock *CloneBasicBlock(const BasicBlock *BB, ValueToValueMapTy &VMap, |
110 | | const Twine &NameSuffix = "", Function *F = nullptr, |
111 | | ClonedCodeInfo *CodeInfo = nullptr, |
112 | | DebugInfoFinder *DIFinder = nullptr); |
113 | | |
114 | | /// 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 |
121 | | /// non-null. |
122 | | /// |
123 | | /// VMap contains no non-identity GlobalValue mappings and debug info metadata |
124 | | /// will not be cloned. |
125 | | /// |
126 | | Function *CloneFunction(Function *F, ValueToValueMapTy &VMap, |
127 | | ClonedCodeInfo *CodeInfo = nullptr); |
128 | | |
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. |
134 | | /// |
135 | | /// If ModuleLevelChanges is false, VMap contains no non-identity GlobalValue |
136 | | /// mappings. |
137 | | /// |
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); |
145 | | |
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); |
152 | | |
153 | | /// 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. |
160 | | /// |
161 | | /// If ModuleLevelChanges is false, VMap contains no non-identity GlobalValue |
162 | | /// mappings. |
163 | | /// |
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); |
170 | | |
171 | | /// This class captures the data input to the InlineFunction call, and records |
172 | | /// the auxiliary results produced by it. |
173 | | class InlineFunctionInfo { |
174 | | public: |
175 | | explicit InlineFunctionInfo(CallGraph *cg = nullptr, |
176 | | std::function<AssumptionCache &(Function &)> |
177 | | *GetAssumptionCache = nullptr, |
178 | | ProfileSummaryInfo *PSI = nullptr, |
179 | | BlockFrequencyInfo *CallerBFI = nullptr, |
180 | | BlockFrequencyInfo *CalleeBFI = nullptr) |
181 | | : CG(cg), GetAssumptionCache(GetAssumptionCache), PSI(PSI), |
182 | 345k | CallerBFI(CallerBFI), CalleeBFI(CalleeBFI) {} |
183 | | |
184 | | /// If non-null, InlineFunction will update the callgraph to reflect the |
185 | | /// changes it makes. |
186 | | CallGraph *CG; |
187 | | std::function<AssumptionCache &(Function &)> *GetAssumptionCache; |
188 | | ProfileSummaryInfo *PSI; |
189 | | BlockFrequencyInfo *CallerBFI, *CalleeBFI; |
190 | | |
191 | | /// InlineFunction fills this in with all static allocas that get copied into |
192 | | /// the caller. |
193 | | SmallVector<AllocaInst *, 4> StaticAllocas; |
194 | | |
195 | | /// InlineFunction fills this in with callsites that were inlined from the |
196 | | /// callee. This is only filled in if CG is non-null. |
197 | | SmallVector<WeakTrackingVH, 8> InlinedCalls; |
198 | | |
199 | | /// All of the new call sites inlined into the caller. |
200 | | /// |
201 | | /// 'InlineFunction' fills this in by scanning the inlined instructions, and |
202 | | /// only if CG is null. If CG is non-null, instead the value handle |
203 | | /// `InlinedCalls` above is used. |
204 | | SmallVector<CallSite, 8> InlinedCallSites; |
205 | | |
206 | 541k | void reset() { |
207 | 541k | StaticAllocas.clear(); |
208 | 541k | InlinedCalls.clear(); |
209 | 541k | InlinedCallSites.clear(); |
210 | 541k | } |
211 | | }; |
212 | | |
213 | | /// This function inlines the called function into the basic |
214 | | /// block of the caller. This returns false if it is not possible to inline |
215 | | /// this call. The program is still in a well defined state if this occurs |
216 | | /// though. |
217 | | /// |
218 | | /// Note that this only does one level of inlining. For example, if the |
219 | | /// instruction 'call B' is inlined, and 'B' calls 'C', then the call to 'C' now |
220 | | /// exists in the instruction stream. Similarly this will inline a recursive |
221 | | /// function by one level. |
222 | | /// |
223 | | /// Note that while this routine is allowed to cleanup and optimize the |
224 | | /// *inlined* code to minimize the actual inserted code, it must not delete |
225 | | /// code in the caller as users of this routine may have pointers to |
226 | | /// instructions in the caller that need to remain stable. |
227 | | /// |
228 | | /// If ForwardVarArgsTo is passed, inlining a function with varargs is allowed |
229 | | /// and all varargs at the callsite will be passed to any calls to |
230 | | /// ForwardVarArgsTo. The caller of InlineFunction has to make sure any varargs |
231 | | /// are only used by ForwardVarArgsTo. |
232 | | InlineResult InlineFunction(CallBase *CB, InlineFunctionInfo &IFI, |
233 | | AAResults *CalleeAAR = nullptr, |
234 | | bool InsertLifetime = true); |
235 | | InlineResult InlineFunction(CallSite CS, InlineFunctionInfo &IFI, |
236 | | AAResults *CalleeAAR = nullptr, |
237 | | bool InsertLifetime = true, |
238 | | Function *ForwardVarArgsTo = nullptr); |
239 | | |
240 | | /// Clones a loop \p OrigLoop. Returns the loop and the blocks in \p |
241 | | /// Blocks. |
242 | | /// |
243 | | /// Updates LoopInfo and DominatorTree assuming the loop is dominated by block |
244 | | /// \p LoopDomBB. Insert the new blocks before block specified in \p Before. |
245 | | /// Note: Only innermost loops are supported. |
246 | | Loop *cloneLoopWithPreheader(BasicBlock *Before, BasicBlock *LoopDomBB, |
247 | | Loop *OrigLoop, ValueToValueMapTy &VMap, |
248 | | const Twine &NameSuffix, LoopInfo *LI, |
249 | | DominatorTree *DT, |
250 | | SmallVectorImpl<BasicBlock *> &Blocks); |
251 | | |
252 | | /// Remaps instructions in \p Blocks using the mapping in \p VMap. |
253 | | void remapInstructionsInBlocks(const SmallVectorImpl<BasicBlock *> &Blocks, |
254 | | ValueToValueMapTy &VMap); |
255 | | |
256 | | /// Split edge between BB and PredBB and duplicate all non-Phi instructions |
257 | | /// from BB between its beginning and the StopAt instruction into the split |
258 | | /// block. Phi nodes are not duplicated, but their uses are handled correctly: |
259 | | /// we replace them with the uses of corresponding Phi inputs. ValueMapping |
260 | | /// is used to map the original instructions from BB to their newly-created |
261 | | /// copies. Returns the split block. |
262 | | BasicBlock *DuplicateInstructionsInSplitBetween(BasicBlock *BB, |
263 | | BasicBlock *PredBB, |
264 | | Instruction *StopAt, |
265 | | ValueToValueMapTy &ValueMapping, |
266 | | DomTreeUpdater &DTU); |
267 | | |
268 | | /// Updates profile information by adjusting the entry count by adding |
269 | | /// entryDelta then scaling callsite information by the new count divided by the |
270 | | /// old count. VMap is used during inlinng to also update the new clone |
271 | | void updateProfileCallee( |
272 | | Function *Callee, int64_t entryDelta, |
273 | | const ValueMap<const Value *, WeakTrackingVH> *VMap = nullptr); |
274 | | |
275 | | } // end namespace llvm |
276 | | |
277 | | #endif // LLVM_TRANSFORMS_UTILS_CLONING_H |