LLVM  6.0.0svn
Cloning.h
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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"
25 #include "llvm/IR/CallSite.h"
26 #include "llvm/IR/ValueHandle.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 
50 /// Return an exact copy of the specified module
51 ///
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 /// ClonedCodeInfo - This struct can be used to capture information about code
64 /// being cloned, while it is being cloned.
66  /// ContainsCalls - This is set to true if the cloned code contains a normal
67  /// call instruction.
68  bool ContainsCalls = false;
69 
70  /// ContainsDynamicAllocas - This is set to true if the cloned code contains
71  /// a 'dynamic' alloca. Dynamic allocas are allocas that are either not in
72  /// the entry block or they are in the entry block but are not a constant
73  /// size.
74  bool ContainsDynamicAllocas = false;
75 
76  /// All cloned call sites that have operand bundles attached are appended to
77  /// this vector. This vector may contain nulls or undefs if some of the
78  /// originally inserted callsites were DCE'ed after they were cloned.
79  std::vector<WeakTrackingVH> OperandBundleCallSites;
80 
81  ClonedCodeInfo() = default;
82 };
83 
84 /// CloneBasicBlock - Return a copy of the specified basic block, but without
85 /// embedding the block into a particular function. The block returned is an
86 /// exact copy of the specified basic block, without any remapping having been
87 /// performed. Because of this, this is only suitable for applications where
88 /// the basic block will be inserted into the same function that it was cloned
89 /// from (loop unrolling would use this, for example).
90 ///
91 /// Also, note that this function makes a direct copy of the basic block, and
92 /// can thus produce illegal LLVM code. In particular, it will copy any PHI
93 /// nodes from the original block, even though there are no predecessors for the
94 /// newly cloned block (thus, phi nodes will have to be updated). Also, this
95 /// block will branch to the old successors of the original block: these
96 /// successors will have to have any PHI nodes updated to account for the new
97 /// incoming edges.
98 ///
99 /// The correlation between instructions in the source and result basic blocks
100 /// is recorded in the VMap map.
101 ///
102 /// If you have a particular suffix you'd like to use to add to any cloned
103 /// names, specify it as the optional third parameter.
104 ///
105 /// If you would like the basic block to be auto-inserted into the end of a
106 /// function, you can specify it as the optional fourth parameter.
107 ///
108 /// If you would like to collect additional information about the cloned
109 /// function, you can specify a ClonedCodeInfo object with the optional fifth
110 /// parameter.
111 ///
113  const Twine &NameSuffix = "", Function *F = nullptr,
114  ClonedCodeInfo *CodeInfo = nullptr,
115  DebugInfoFinder *DIFinder = nullptr);
116 
117 /// CloneFunction - Return a copy of the specified function and add it to that
118 /// function's module. Also, any references specified in the VMap are changed
119 /// to refer to their mapped value instead of the original one. If any of the
120 /// arguments to the function are in the VMap, the arguments are deleted from
121 /// the resultant function. The VMap is updated to include mappings from all of
122 /// the instructions and basicblocks in the function from their old to new
123 /// values. The final argument captures information about the cloned code if
124 /// non-null.
125 ///
126 /// VMap contains no non-identity GlobalValue mappings and debug info metadata
127 /// will not be cloned.
128 ///
130  ClonedCodeInfo *CodeInfo = nullptr);
131 
132 /// Clone OldFunc into NewFunc, transforming the old arguments into references
133 /// to VMap values. Note that if NewFunc already has basic blocks, the ones
134 /// cloned into it will be added to the end of the function. This function
135 /// fills in a list of return instructions, and can optionally remap types
136 /// and/or append the specified suffix to all values cloned.
137 ///
138 /// If ModuleLevelChanges is false, VMap contains no non-identity GlobalValue
139 /// mappings.
140 ///
141 void CloneFunctionInto(Function *NewFunc, const Function *OldFunc,
142  ValueToValueMapTy &VMap, bool ModuleLevelChanges,
144  const char *NameSuffix = "",
145  ClonedCodeInfo *CodeInfo = nullptr,
146  ValueMapTypeRemapper *TypeMapper = nullptr,
147  ValueMaterializer *Materializer = nullptr);
148 
149 void CloneAndPruneIntoFromInst(Function *NewFunc, const Function *OldFunc,
150  const Instruction *StartingInst,
151  ValueToValueMapTy &VMap, bool ModuleLevelChanges,
153  const char *NameSuffix = "",
154  ClonedCodeInfo *CodeInfo = nullptr);
155 
156 /// CloneAndPruneFunctionInto - This works exactly like CloneFunctionInto,
157 /// except that it does some simple constant prop and DCE on the fly. The
158 /// effect of this is to copy significantly less code in cases where (for
159 /// example) a function call with constant arguments is inlined, and those
160 /// constant arguments cause a significant amount of code in the callee to be
161 /// dead. Since this doesn't produce an exactly copy of the input, it can't be
162 /// used for things like CloneFunction or CloneModule.
163 ///
164 /// If ModuleLevelChanges is false, VMap contains no non-identity GlobalValue
165 /// mappings.
166 ///
167 void CloneAndPruneFunctionInto(Function *NewFunc, const Function *OldFunc,
168  ValueToValueMapTy &VMap, bool ModuleLevelChanges,
170  const char *NameSuffix = "",
171  ClonedCodeInfo *CodeInfo = nullptr,
172  Instruction *TheCall = nullptr);
173 
174 /// InlineFunctionInfo - This class captures the data input to the
175 /// InlineFunction call, and records the auxiliary results produced by it.
177 public:
178  explicit InlineFunctionInfo(CallGraph *cg = nullptr,
180  *GetAssumptionCache = nullptr,
181  ProfileSummaryInfo *PSI = nullptr,
182  BlockFrequencyInfo *CallerBFI = nullptr,
183  BlockFrequencyInfo *CalleeBFI = nullptr)
184  : CG(cg), GetAssumptionCache(GetAssumptionCache), PSI(PSI),
185  CallerBFI(CallerBFI), CalleeBFI(CalleeBFI) {}
186 
187  /// CG - If non-null, InlineFunction will update the callgraph to reflect the
188  /// changes it makes.
190  std::function<AssumptionCache &(Function &)> *GetAssumptionCache;
193 
194  /// StaticAllocas - InlineFunction fills this in with all static allocas that
195  /// get copied into the caller.
197 
198  /// InlinedCalls - InlineFunction fills this in with callsites that were
199  /// inlined from the callee. This is only filled in if CG is non-null.
201 
202  /// All of the new call sites inlined into the caller.
203  ///
204  /// 'InlineFunction' fills this in by scanning the inlined instructions, and
205  /// only if CG is null. If CG is non-null, instead the value handle
206  /// `InlinedCalls` above is used.
208 
209  void reset() {
210  StaticAllocas.clear();
211  InlinedCalls.clear();
212  InlinedCallSites.clear();
213  }
214 };
215 
216 /// InlineFunction - This function inlines the called function into the basic
217 /// block of the caller. This returns false if it is not possible to inline
218 /// this call. The program is still in a well defined state if this occurs
219 /// though.
220 ///
221 /// Note that this only does one level of inlining. For example, if the
222 /// instruction 'call B' is inlined, and 'B' calls 'C', then the call to 'C' now
223 /// exists in the instruction stream. Similarly this will inline a recursive
224 /// function by one level.
225 ///
226 /// Note that while this routine is allowed to cleanup and optimize the
227 /// *inlined* code to minimize the actual inserted code, it must not delete
228 /// code in the caller as users of this routine may have pointers to
229 /// instructions in the caller that need to remain stable.
230 ///
231 /// If ForwardVarArgsTo is passed, inlining a function with varargs is allowed
232 /// and all varargs at the callsite will be passed to any calls to
233 /// ForwardVarArgsTo. The caller of InlineFunction has to make sure any varargs
234 /// are only used by ForwardVarArgsTo.
236  AAResults *CalleeAAR = nullptr, bool InsertLifetime = true);
238  AAResults *CalleeAAR = nullptr, bool InsertLifetime = true);
240  AAResults *CalleeAAR = nullptr, bool InsertLifetime = true,
241  Function *ForwardVarArgsTo = nullptr);
242 
243 /// \brief Clones a loop \p OrigLoop. Returns the loop and the blocks in \p
244 /// Blocks.
245 ///
246 /// Updates LoopInfo and DominatorTree assuming the loop is dominated by block
247 /// \p LoopDomBB. Insert the new blocks before block specified in \p Before.
248 /// Note: Only innermost loops are supported.
249 Loop *cloneLoopWithPreheader(BasicBlock *Before, BasicBlock *LoopDomBB,
250  Loop *OrigLoop, ValueToValueMapTy &VMap,
251  const Twine &NameSuffix, LoopInfo *LI,
252  DominatorTree *DT,
254 
255 /// \brief Remaps instructions in \p Blocks using the mapping in \p VMap.
257  ValueToValueMapTy &VMap);
258 
259 /// Split edge between BB and PredBB and duplicate all non-Phi instructions
260 /// from BB between its beginning and the StopAt instruction into the split
261 /// block. Phi nodes are not duplicated, but their uses are handled correctly:
262 /// we replace them with the uses of corresponding Phi inputs. ValueMapping
263 /// is used to map the original instructions from BB to their newly-created
264 /// copies. Returns the split block.
265 BasicBlock *
267  Instruction *StopAt,
269 } // end namespace llvm
270 
271 #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:189
Various leaf nodes.
Definition: ISDOpcodes.h:60
std::function< AssumptionCache &(Function &)> * GetAssumptionCache
Definition: Cloning.h:190
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 .assume calls within a function.
F(f)
InlineFunctionInfo - This class captures the data input to the InlineFunction call, and records the auxiliary results produced by it.
Definition: Cloning.h:176
bool 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...
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:79
Concrete subclass of DominatorTreeBase that is used to compute a normal dominator tree...
Definition: Dominators.h:140
ClonedCodeInfo()=default
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:207
LLVM Basic Block Representation.
Definition: BasicBlock.h:59
ProfileSummaryInfo * PSI
Definition: Cloning.h:191
std::unique_ptr< Module > CloneModule(const Module *M)
Return an exact copy of the specified module.
Definition: CloneModule.cpp:36
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...
ValueMap< const Value *, WeakTrackingVH > ValueToValueMapTy
Definition: ValueMapper.h:34
InlineFunctionInfo(CallGraph *cg=nullptr, std::function< AssumptionCache &(Function &)> *GetAssumptionCache=nullptr, ProfileSummaryInfo *PSI=nullptr, BlockFrequencyInfo *CallerBFI=nullptr, BlockFrequencyInfo *CalleeBFI=nullptr)
Definition: Cloning.h:178
This is a &#39;vector&#39; (really, a variable-sized array), optimized for the case when the array is small...
Definition: SmallVector.h:864
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 ...
BasicBlock * DuplicateInstructionsInSplitBetween(BasicBlock *BB, BasicBlock *PredBB, Instruction *StopAt, ValueToValueMapTy &ValueMapping)
Split edge between BB and PredBB and duplicate all non-Phi instructions from BB between its beginning...
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:68
SmallVector< AllocaInst *, 4 > StaticAllocas
StaticAllocas - InlineFunction fills this in with all static allocas that get copied into the caller...
Definition: Cloning.h:196
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:200
Represents a single loop in the control flow graph.
Definition: LoopInfo.h:439
ClonedCodeInfo - This struct can be used to capture information about code being cloned, while it is being cloned.
Definition: Cloning.h:65
Helper struct that represents how a value is mapped through different register banks.
BlockFrequencyInfo * CallerBFI
Definition: Cloning.h:192
bool ContainsDynamicAllocas
ContainsDynamicAllocas - This is set to true if the cloned code contains a &#39;dynamic&#39; alloca...
Definition: Cloning.h:74
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.