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.
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.
21#include "llvm/ADT/SmallVector.h"
22#include "llvm/ADT/Twine.h"
23#include "llvm/IR/ValueHandle.h"
24#include "llvm/IR/ValueMap.h"
25#include "llvm/Transforms/Utils/ValueMapper.h"
27namespace llvm {
29class Module;
30class Function;
31class Instruction;
32class Pass;
33class LPPassManager;
34class BasicBlock;
35class Value;
36class CallInst;
37class InvokeInst;
38class ReturnInst;
39class CallSite;
40class Trace;
41class CallGraph;
42class DataLayout;
43class Loop;
44class LoopInfo;
45class AllocaInst;
47/// CloneModule - Return an exact copy of the specified module
49Module *CloneModule(const Module *M);
50Module *CloneModule(const Module *M, ValueToValueMapTy &VMap);
52/// ClonedCodeInfo - This struct can be used to capture information about code
53/// being cloned, while it is being cloned.
54struct ClonedCodeInfo {
55  /// ContainsCalls - This is set to true if the cloned code contains a normal
56  /// call instruction.
57  bool ContainsCalls;
59  /// ContainsDynamicAllocas - This is set to true if the cloned code contains
60  /// a 'dynamic' alloca.  Dynamic allocas are allocas that are either not in
61  /// the entry block or they are in the entry block but are not a constant
62  /// size.
63  bool ContainsDynamicAllocas;
65  ClonedCodeInfo() : ContainsCalls(false), ContainsDynamicAllocas(false) {}
68/// CloneBasicBlock - Return a copy of the specified basic block, but without
69/// embedding the block into a particular function.  The block returned is an
70/// exact copy of the specified basic block, without any remapping having been
71/// performed.  Because of this, this is only suitable for applications where
72/// the basic block will be inserted into the same function that it was cloned
73/// from (loop unrolling would use this, for example).
75/// Also, note that this function makes a direct copy of the basic block, and
76/// can thus produce illegal LLVM code.  In particular, it will copy any PHI
77/// nodes from the original block, even though there are no predecessors for the
78/// newly cloned block (thus, phi nodes will have to be updated).  Also, this
79/// block will branch to the old successors of the original block: these
80/// successors will have to have any PHI nodes updated to account for the new
81/// incoming edges.
83/// The correlation between instructions in the source and result basic blocks
84/// is recorded in the VMap map.
86/// If you have a particular suffix you'd like to use to add to any cloned
87/// names, specify it as the optional third parameter.
89/// If you would like the basic block to be auto-inserted into the end of a
90/// function, you can specify it as the optional fourth parameter.
92/// If you would like to collect additional information about the cloned
93/// function, you can specify a ClonedCodeInfo object with the optional fifth
94/// parameter.
96BasicBlock *CloneBasicBlock(const BasicBlock *BB,
97                            ValueToValueMapTy &VMap,
98                            const Twine &NameSuffix = "", Function *F = nullptr,
99                            ClonedCodeInfo *CodeInfo = nullptr);
101/// CloneFunction - Return a copy of the specified function, but without
102/// embedding the function into another module.  Also, any references specified
103/// in the VMap are changed to refer to their mapped value instead of the
104/// original one.  If any of the arguments to the function are in the VMap,
105/// the arguments are deleted from the resultant function.  The VMap is
106/// updated to include mappings from all of the instructions and basicblocks in
107/// the function from their old to new values.  The final argument captures
108/// information about the cloned code if non-null.
110/// If ModuleLevelChanges is false, VMap contains no non-identity GlobalValue
111/// mappings, and debug info metadata will not be cloned.
113Function *CloneFunction(const Function *F,
114                        ValueToValueMapTy &VMap,
115                        bool ModuleLevelChanges,
116                        ClonedCodeInfo *CodeInfo = nullptr);
118/// Clone OldFunc into NewFunc, transforming the old arguments into references
119/// to VMap values.  Note that if NewFunc already has basic blocks, the ones
120/// cloned into it will be added to the end of the function.  This function
121/// fills in a list of return instructions, and can optionally remap types
122/// and/or append the specified suffix to all values cloned.
124/// If ModuleLevelChanges is false, VMap contains no non-identity GlobalValue
125/// mappings.
127void CloneFunctionInto(Function *NewFunc, const Function *OldFunc,
128                       ValueToValueMapTy &VMap,
129                       bool ModuleLevelChanges,
130                       SmallVectorImpl<ReturnInst*> &Returns,
131                       const char *NameSuffix = "",
132                       ClonedCodeInfo *CodeInfo = nullptr,
133                       ValueMapTypeRemapper *TypeMapper = nullptr,
134                       ValueMaterializer *Materializer = nullptr);
136/// CloneAndPruneFunctionInto - This works exactly like CloneFunctionInto,
137/// except that it does some simple constant prop and DCE on the fly.  The
138/// effect of this is to copy significantly less code in cases where (for
139/// example) a function call with constant arguments is inlined, and those
140/// constant arguments cause a significant amount of code in the callee to be
141/// dead.  Since this doesn't produce an exactly copy of the input, it can't be
142/// used for things like CloneFunction or CloneModule.
144/// If ModuleLevelChanges is false, VMap contains no non-identity GlobalValue
145/// mappings.
147void CloneAndPruneFunctionInto(Function *NewFunc, const Function *OldFunc,
148                               ValueToValueMapTy &VMap,
149                               bool ModuleLevelChanges,
150                               SmallVectorImpl<ReturnInst*> &Returns,
151                               const char *NameSuffix = "",
152                               ClonedCodeInfo *CodeInfo = nullptr,
153                               const DataLayout *DL = nullptr,
154                               Instruction *TheCall = nullptr);
156/// InlineFunctionInfo - This class captures the data input to the
157/// InlineFunction call, and records the auxiliary results produced by it.
158class InlineFunctionInfo {
160  explicit InlineFunctionInfo(CallGraph *cg = nullptr, const DataLayout *DL = nullptr)
161    : CG(cg), DL(DL) {}
163  /// CG - If non-null, InlineFunction will update the callgraph to reflect the
164  /// changes it makes.
165  CallGraph *CG;
166  const DataLayout *DL;
168  /// StaticAllocas - InlineFunction fills this in with all static allocas that
169  /// get copied into the caller.
170  SmallVector<AllocaInst*, 4> StaticAllocas;
172  /// InlinedCalls - InlineFunction fills this in with callsites that were
173  /// inlined from the callee.  This is only filled in if CG is non-null.
174  SmallVector<WeakVH, 8> InlinedCalls;
176  void reset() {
177    StaticAllocas.clear();
178    InlinedCalls.clear();
179  }
182/// InlineFunction - This function inlines the called function into the basic
183/// block of the caller.  This returns false if it is not possible to inline
184/// this call.  The program is still in a well defined state if this occurs
185/// though.
187/// Note that this only does one level of inlining.  For example, if the
188/// instruction 'call B' is inlined, and 'B' calls 'C', then the call to 'C' now
189/// exists in the instruction stream.  Similarly this will inline a recursive
190/// function by one level.
192bool InlineFunction(CallInst *C, InlineFunctionInfo &IFI, bool InsertLifetime = true);
193bool InlineFunction(InvokeInst *II, InlineFunctionInfo &IFI, bool InsertLifetime = true);
194bool InlineFunction(CallSite CS, InlineFunctionInfo &IFI, bool InsertLifetime = true);
196} // End llvm namespace