LLVM  8.0.0svn
Cloning.h
Go to the documentation of this file.
1 //===- Cloning.h - Clone various parts of LLVM programs ---------*- C++ -*-===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
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
14 // formation, etc.
15 //
16 //===----------------------------------------------------------------------===//
17 
18 #ifndef LLVM_TRANSFORMS_UTILS_CLONING_H
19 #define LLVM_TRANSFORMS_UTILS_CLONING_H
20 
21 #include "llvm/ADT/SmallVector.h"
22 #include "llvm/ADT/Twine.h"
26 #include "llvm/IR/CallSite.h"
27 #include "llvm/IR/ValueHandle.h"
29 #include <functional>
30 #include <memory>
31 #include <vector>
32 
33 namespace llvm {
34 
35 class AllocaInst;
36 class BasicBlock;
37 class BlockFrequencyInfo;
38 class CallInst;
39 class CallGraph;
40 class DebugInfoFinder;
41 class DominatorTree;
42 class Function;
43 class Instruction;
44 class InvokeInst;
45 class Loop;
46 class LoopInfo;
47 class Module;
48 class ProfileSummaryInfo;
49 class ReturnInst;
50 
51 /// Return an exact copy of the specified module
52 ///
53 std::unique_ptr<Module> CloneModule(const Module &M);
54 std::unique_ptr<Module> CloneModule(const Module &M, ValueToValueMapTy &VMap);
55 
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  function_ref<bool(const GlobalValue *)> ShouldCloneDefinition);
63 
64 /// ClonedCodeInfo - This struct can be used to capture information about code
65 /// being cloned, while it is being cloned.
67  /// ContainsCalls - This is set to true if the cloned code contains a normal
68  /// call instruction.
69  bool ContainsCalls = false;
70 
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
74  /// size.
75  bool ContainsDynamicAllocas = false;
76 
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<WeakTrackingVH> OperandBundleCallSites;
81 
82  ClonedCodeInfo() = default;
83 };
84 
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).
91 ///
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
98 /// incoming edges.
99 ///
100 /// The correlation between instructions in the source and result basic blocks
101 /// is recorded in the VMap map.
102 ///
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.
105 ///
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.
108 ///
109 /// If you would like to collect additional information about the cloned
110 /// function, you can specify a ClonedCodeInfo object with the optional fifth
111 /// parameter.
112 ///
114  const Twine &NameSuffix = "", Function *F = nullptr,
115  ClonedCodeInfo *CodeInfo = nullptr,
116  DebugInfoFinder *DIFinder = nullptr);
117 
118 /// CloneFunction - Return a copy of the specified function and add it to that
119 /// function's module. Also, any references specified in the VMap are changed
120 /// to refer to their mapped value instead of the original one. If any of the
121 /// arguments to the function are in the VMap, the arguments are deleted from
122 /// the resultant function. The VMap is updated to include mappings from all of
123 /// the instructions and basicblocks in the function from their old to new
124 /// values. The final argument captures information about the cloned code if
125 /// non-null.
126 ///
127 /// VMap contains no non-identity GlobalValue mappings and debug info metadata
128 /// will not be cloned.
129 ///
131  ClonedCodeInfo *CodeInfo = nullptr);
132 
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.
138 ///
139 /// If ModuleLevelChanges is false, VMap contains no non-identity GlobalValue
140 /// mappings.
141 ///
142 void CloneFunctionInto(Function *NewFunc, const Function *OldFunc,
143  ValueToValueMapTy &VMap, bool ModuleLevelChanges,
145  const char *NameSuffix = "",
146  ClonedCodeInfo *CodeInfo = nullptr,
147  ValueMapTypeRemapper *TypeMapper = nullptr,
148  ValueMaterializer *Materializer = nullptr);
149 
150 void CloneAndPruneIntoFromInst(Function *NewFunc, const Function *OldFunc,
151  const Instruction *StartingInst,
152  ValueToValueMapTy &VMap, bool ModuleLevelChanges,
154  const char *NameSuffix = "",
155  ClonedCodeInfo *CodeInfo = nullptr);
156 
157 /// CloneAndPruneFunctionInto - This works exactly like CloneFunctionInto,
158 /// except that it does some simple constant prop and DCE on the fly. The
159 /// effect of this is to copy significantly less code in cases where (for
160 /// example) a function call with constant arguments is inlined, and those
161 /// constant arguments cause a significant amount of code in the callee to be
162 /// dead. Since this doesn't produce an exactly copy of the input, it can't be
163 /// used for things like CloneFunction or CloneModule.
164 ///
165 /// If ModuleLevelChanges is false, VMap contains no non-identity GlobalValue
166 /// mappings.
167 ///
168 void CloneAndPruneFunctionInto(Function *NewFunc, const Function *OldFunc,
169  ValueToValueMapTy &VMap, bool ModuleLevelChanges,
171  const char *NameSuffix = "",
172  ClonedCodeInfo *CodeInfo = nullptr,
173  Instruction *TheCall = nullptr);
174 
175 /// InlineFunctionInfo - This class captures the data input to the
176 /// InlineFunction call, and records the auxiliary results produced by it.
178 public:
179  explicit InlineFunctionInfo(CallGraph *cg = nullptr,
181  *GetAssumptionCache = nullptr,
182  ProfileSummaryInfo *PSI = nullptr,
183  BlockFrequencyInfo *CallerBFI = nullptr,
184  BlockFrequencyInfo *CalleeBFI = nullptr)
185  : CG(cg), GetAssumptionCache(GetAssumptionCache), PSI(PSI),
186  CallerBFI(CallerBFI), CalleeBFI(CalleeBFI) {}
187 
188  /// CG - If non-null, InlineFunction will update the callgraph to reflect the
189  /// changes it makes.
191  std::function<AssumptionCache &(Function &)> *GetAssumptionCache;
194 
195  /// StaticAllocas - InlineFunction fills this in with all static allocas that
196  /// get copied into the caller.
198 
199  /// InlinedCalls - InlineFunction fills this in with callsites that were
200  /// inlined from the callee. This is only filled in if CG is non-null.
202 
203  /// All of the new call sites inlined into the caller.
204  ///
205  /// 'InlineFunction' fills this in by scanning the inlined instructions, and
206  /// only if CG is null. If CG is non-null, instead the value handle
207  /// `InlinedCalls` above is used.
209 
210  void reset() {
211  StaticAllocas.clear();
212  InlinedCalls.clear();
213  InlinedCallSites.clear();
214  }
215 };
216 
217 /// InlineFunction - This function inlines the called function into the basic
218 /// block of the caller. This returns false if it is not possible to inline
219 /// this call. The program is still in a well defined state if this occurs
220 /// though.
221 ///
222 /// Note that this only does one level of inlining. For example, if the
223 /// instruction 'call B' is inlined, and 'B' calls 'C', then the call to 'C' now
224 /// exists in the instruction stream. Similarly this will inline a recursive
225 /// function by one level.
226 ///
227 /// Note that while this routine is allowed to cleanup and optimize the
228 /// *inlined* code to minimize the actual inserted code, it must not delete
229 /// code in the caller as users of this routine may have pointers to
230 /// instructions in the caller that need to remain stable.
231 ///
232 /// If ForwardVarArgsTo is passed, inlining a function with varargs is allowed
233 /// and all varargs at the callsite will be passed to any calls to
234 /// ForwardVarArgsTo. The caller of InlineFunction has to make sure any varargs
235 /// are only used by ForwardVarArgsTo.
237  AAResults *CalleeAAR = nullptr,
238  bool InsertLifetime = true);
240  AAResults *CalleeAAR = nullptr,
241  bool InsertLifetime = true);
243  AAResults *CalleeAAR = nullptr,
244  bool InsertLifetime = true,
245  Function *ForwardVarArgsTo = nullptr);
246 
247 /// Clones a loop \p OrigLoop. Returns the loop and the blocks in \p
248 /// Blocks.
249 ///
250 /// Updates LoopInfo and DominatorTree assuming the loop is dominated by block
251 /// \p LoopDomBB. Insert the new blocks before block specified in \p Before.
252 /// Note: Only innermost loops are supported.
253 Loop *cloneLoopWithPreheader(BasicBlock *Before, BasicBlock *LoopDomBB,
254  Loop *OrigLoop, ValueToValueMapTy &VMap,
255  const Twine &NameSuffix, LoopInfo *LI,
256  DominatorTree *DT,
258 
259 /// Remaps instructions in \p Blocks using the mapping in \p VMap.
261  ValueToValueMapTy &VMap);
262 
263 /// Split edge between BB and PredBB and duplicate all non-Phi instructions
264 /// from BB between its beginning and the StopAt instruction into the split
265 /// block. Phi nodes are not duplicated, but their uses are handled correctly:
266 /// we replace them with the uses of corresponding Phi inputs. ValueMapping
267 /// is used to map the original instructions from BB to their newly-created
268 /// copies. Returns the split block.
269 BasicBlock *
271  Instruction *StopAt,
273  DominatorTree *DT = nullptr);
274 } // end namespace llvm
275 
276 #endif // LLVM_TRANSFORMS_UTILS_CLONING_H
uint64_t CallInst * C
Compute iterated dominance frontiers using a linear time algorithm.
Definition: AllocatorList.h:24
CallGraph * CG
CG - If non-null, InlineFunction will update the callgraph to reflect the changes it makes...
Definition: Cloning.h:190
Various leaf nodes.
Definition: ISDOpcodes.h:60
std::function< AssumptionCache &(Function &)> * GetAssumptionCache
Definition: Cloning.h:191
BasicBlock * DuplicateInstructionsInSplitBetween(BasicBlock *BB, BasicBlock *PredBB, Instruction *StopAt, ValueToValueMapTy &ValueMapping, DominatorTree *DT=nullptr)
Split edge between BB and PredBB and duplicate all non-Phi instructions from BB between its beginning...
Analysis providing profile information.
This class represents a function call, abstracting a target machine&#39;s calling convention.
Function * CloneFunction(Function *F, ValueToValueMapTy &VMap, ClonedCodeInfo *CodeInfo=nullptr)
CloneFunction - Return a copy of the specified function and add it to that function&#39;s module...
A cache of @llvm.assume calls within a function.
F(f)
InlineResult InlineFunction(CallInst *C, InlineFunctionInfo &IFI, AAResults *CalleeAAR=nullptr, bool InsertLifetime=true)
InlineFunction - This function inlines the called function into the basic block of the caller...
InlineFunctionInfo - This class captures the data input to the InlineFunction call, and records the auxiliary results produced by it.
Definition: Cloning.h:177
void CloneFunctionInto(Function *NewFunc, const Function *OldFunc, ValueToValueMapTy &VMap, bool ModuleLevelChanges, SmallVectorImpl< ReturnInst *> &Returns, const char *NameSuffix="", ClonedCodeInfo *CodeInfo=nullptr, ValueMapTypeRemapper *TypeMapper=nullptr, ValueMaterializer *Materializer=nullptr)
Clone OldFunc into NewFunc, transforming the old arguments into references to VMap values...
Twine - A lightweight data structure for efficiently representing the concatenation of temporary valu...
Definition: Twine.h:81
This class consists of common code factored out of the SmallVector class to reduce code duplication b...
Definition: APFloat.h:42
Utility to find all debug info in a module.
Definition: DebugInfo.h:65
void CloneAndPruneFunctionInto(Function *NewFunc, const Function *OldFunc, ValueToValueMapTy &VMap, bool ModuleLevelChanges, SmallVectorImpl< ReturnInst *> &Returns, const char *NameSuffix="", ClonedCodeInfo *CodeInfo=nullptr, Instruction *TheCall=nullptr)
CloneAndPruneFunctionInto - This works exactly like CloneFunctionInto, except that it does some simpl...
std::vector< WeakTrackingVH > OperandBundleCallSites
All cloned call sites that have operand bundles attached are appended to this vector.
Definition: Cloning.h:80
InlineResult is basically true or false.
Definition: InlineCost.h:137
Concrete subclass of DominatorTreeBase that is used to compute a normal dominator tree...
Definition: Dominators.h:145
ClonedCodeInfo()=default
std::unique_ptr< Module > CloneModule(const Module &M)
Return an exact copy of the specified module.
Definition: CloneModule.cpp:35
BlockFrequencyInfo pass uses BlockFrequencyInfoImpl implementation to estimate IR basic block frequen...
This is a class that can be implemented by clients to materialize Values on demand.
Definition: ValueMapper.h:51
SmallVector< CallSite, 8 > InlinedCallSites
All of the new call sites inlined into the caller.
Definition: Cloning.h:208
ValueMap< const Value *, WeakTrackingVH > ValueToValueMapTy
LLVM Basic Block Representation.
Definition: BasicBlock.h:58
ProfileSummaryInfo * PSI
Definition: Cloning.h:192
void CloneAndPruneIntoFromInst(Function *NewFunc, const Function *OldFunc, const Instruction *StartingInst, ValueToValueMapTy &VMap, bool ModuleLevelChanges, SmallVectorImpl< ReturnInst *> &Returns, const char *NameSuffix="", ClonedCodeInfo *CodeInfo=nullptr)
This works like CloneAndPruneFunctionInto, except that it does not clone the entire function...
InlineFunctionInfo(CallGraph *cg=nullptr, std::function< AssumptionCache &(Function &)> *GetAssumptionCache=nullptr, ProfileSummaryInfo *PSI=nullptr, BlockFrequencyInfo *CallerBFI=nullptr, BlockFrequencyInfo *CalleeBFI=nullptr)
Definition: Cloning.h:179
This is a &#39;vector&#39; (really, a variable-sized array), optimized for the case when the array is small...
Definition: SmallVector.h:847
BasicBlock * CloneBasicBlock(const BasicBlock *BB, ValueToValueMapTy &VMap, const Twine &NameSuffix="", Function *F=nullptr, ClonedCodeInfo *CodeInfo=nullptr, DebugInfoFinder *DIFinder=nullptr)
CloneBasicBlock - Return a copy of the specified basic block, but without embedding the block into a ...
This is a class that can be implemented by clients to remap types when cloning constants and instruct...
Definition: ValueMapper.h:38
bool ContainsCalls
ContainsCalls - This is set to true if the cloned code contains a normal call instruction.
Definition: Cloning.h:69
SmallVector< AllocaInst *, 4 > StaticAllocas
StaticAllocas - InlineFunction fills this in with all static allocas that get copied into the caller...
Definition: Cloning.h:197
The basic data container for the call graph of a Module of IR.
Definition: CallGraph.h:74
SmallVector< WeakTrackingVH, 8 > InlinedCalls
InlinedCalls - InlineFunction fills this in with callsites that were inlined from the callee...
Definition: Cloning.h:201
Represents a single loop in the control flow graph.
Definition: LoopInfo.h:459
ClonedCodeInfo - This struct can be used to capture information about code being cloned, while it is being cloned.
Definition: Cloning.h:66
Helper struct that represents how a value is mapped through different register banks.
BlockFrequencyInfo * CallerBFI
Definition: Cloning.h:193
bool ContainsDynamicAllocas
ContainsDynamicAllocas - This is set to true if the cloned code contains a &#39;dynamic&#39; alloca...
Definition: Cloning.h:75
Loop * cloneLoopWithPreheader(BasicBlock *Before, BasicBlock *LoopDomBB, Loop *OrigLoop, ValueToValueMapTy &VMap, const Twine &NameSuffix, LoopInfo *LI, DominatorTree *DT, SmallVectorImpl< BasicBlock *> &Blocks)
Clones a loop OrigLoop.
Invoke instruction.
print Print MemDeps of function
void remapInstructionsInBlocks(const SmallVectorImpl< BasicBlock *> &Blocks, ValueToValueMapTy &VMap)
Remaps instructions in Blocks using the mapping in VMap.