Cloning.h revision 263508 
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"
23#include "llvm/ADT/ValueMap.h"
24#include "llvm/Support/ValueHandle.h"
25#include "llvm/Transforms/Utils/ValueMapper.h"
26
27namespace llvm {
28
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;
46
47/// CloneModule - Return an exact copy of the specified module
48///
49Module *CloneModule(const Module *M);
50Module *CloneModule(const Module *M, ValueToValueMapTy &VMap);
51
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;
58
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;
64
65  ClonedCodeInfo() : ContainsCalls(false), ContainsDynamicAllocas(false) {}
66};
67
68
69/// CloneBasicBlock - Return a copy of the specified basic block, but without
70/// embedding the block into a particular function.  The block returned is an
71/// exact copy of the specified basic block, without any remapping having been
72/// performed.  Because of this, this is only suitable for applications where
73/// the basic block will be inserted into the same function that it was cloned
74/// from (loop unrolling would use this, for example).
75///
76/// Also, note that this function makes a direct copy of the basic block, and
77/// can thus produce illegal LLVM code.  In particular, it will copy any PHI
78/// nodes from the original block, even though there are no predecessors for the
79/// newly cloned block (thus, phi nodes will have to be updated).  Also, this
80/// block will branch to the old successors of the original block: these
81/// successors will have to have any PHI nodes updated to account for the new
82/// incoming edges.
83///
84/// The correlation between instructions in the source and result basic blocks
85/// is recorded in the VMap map.
86///
87/// If you have a particular suffix you'd like to use to add to any cloned
88/// names, specify it as the optional third parameter.
89///
90/// If you would like the basic block to be auto-inserted into the end of a
91/// function, you can specify it as the optional fourth parameter.
92///
93/// If you would like to collect additional information about the cloned
94/// function, you can specify a ClonedCodeInfo object with the optional fifth
95/// parameter.
96///
97BasicBlock *CloneBasicBlock(const BasicBlock *BB,
98                            ValueToValueMapTy &VMap,
99                            const Twine &NameSuffix = "", Function *F = 0,
100                            ClonedCodeInfo *CodeInfo = 0);
101
102/// CloneFunction - Return a copy of the specified function, but without
103/// embedding the function into another module.  Also, any references specified
104/// in the VMap are changed to refer to their mapped value instead of the
105/// original one.  If any of the arguments to the function are in the VMap,
106/// the arguments are deleted from the resultant function.  The VMap is
107/// updated to include mappings from all of the instructions and basicblocks in
108/// the function from their old to new values.  The final argument captures
109/// information about the cloned code if non-null.
110///
111/// If ModuleLevelChanges is false, VMap contains no non-identity GlobalValue
112/// mappings.
113///
114Function *CloneFunction(const Function *F,
115                        ValueToValueMapTy &VMap,
116                        bool ModuleLevelChanges,
117                        ClonedCodeInfo *CodeInfo = 0);
118
119/// Clone OldFunc into NewFunc, transforming the old arguments into references
120/// to VMap values.  Note that if NewFunc already has basic blocks, the ones
121/// cloned into it will be added to the end of the function.  This function
122/// fills in a list of return instructions, and can optionally remap types
123/// and/or append the specified suffix to all values cloned.
124///
125/// If ModuleLevelChanges is false, VMap contains no non-identity GlobalValue
126/// mappings.
127///
128void CloneFunctionInto(Function *NewFunc, const Function *OldFunc,
129                       ValueToValueMapTy &VMap,
130                       bool ModuleLevelChanges,
131                       SmallVectorImpl<ReturnInst*> &Returns,
132                       const char *NameSuffix = "",
133                       ClonedCodeInfo *CodeInfo = 0,
134                       ValueMapTypeRemapper *TypeMapper = 0,
135                       ValueMaterializer *Materializer = 0);
136
137/// CloneAndPruneFunctionInto - This works exactly like CloneFunctionInto,
138/// except that it does some simple constant prop and DCE on the fly.  The
139/// effect of this is to copy significantly less code in cases where (for
140/// example) a function call with constant arguments is inlined, and those
141/// constant arguments cause a significant amount of code in the callee to be
142/// dead.  Since this doesn't produce an exactly copy of the input, it can't be
143/// used for things like CloneFunction or CloneModule.
144///
145/// If ModuleLevelChanges is false, VMap contains no non-identity GlobalValue
146/// mappings.
147///
148void CloneAndPruneFunctionInto(Function *NewFunc, const Function *OldFunc,
149                               ValueToValueMapTy &VMap,
150                               bool ModuleLevelChanges,
151                               SmallVectorImpl<ReturnInst*> &Returns,
152                               const char *NameSuffix = "",
153                               ClonedCodeInfo *CodeInfo = 0,
154                               const DataLayout *TD = 0,
155                               Instruction *TheCall = 0);
156
157
158/// InlineFunctionInfo - This class captures the data input to the
159/// InlineFunction call, and records the auxiliary results produced by it.
160class InlineFunctionInfo {
161public:
162  explicit InlineFunctionInfo(CallGraph *cg = 0, const DataLayout *td = 0)
163    : CG(cg), TD(td) {}
164
165  /// CG - If non-null, InlineFunction will update the callgraph to reflect the
166  /// changes it makes.
167  CallGraph *CG;
168  const DataLayout *TD;
169
170  /// StaticAllocas - InlineFunction fills this in with all static allocas that
171  /// get copied into the caller.
172  SmallVector<AllocaInst*, 4> StaticAllocas;
173
174  /// InlinedCalls - InlineFunction fills this in with callsites that were
175  /// inlined from the callee.  This is only filled in if CG is non-null.
176  SmallVector<WeakVH, 8> InlinedCalls;
177
178  void reset() {
179    StaticAllocas.clear();
180    InlinedCalls.clear();
181  }
182};
183
184/// InlineFunction - This function inlines the called function into the basic
185/// block of the caller.  This returns false if it is not possible to inline
186/// this call.  The program is still in a well defined state if this occurs
187/// though.
188///
189/// Note that this only does one level of inlining.  For example, if the
190/// instruction 'call B' is inlined, and 'B' calls 'C', then the call to 'C' now
191/// exists in the instruction stream.  Similarly this will inline a recursive
192/// function by one level.
193///
194bool InlineFunction(CallInst *C, InlineFunctionInfo &IFI, bool InsertLifetime = true);
195bool InlineFunction(InvokeInst *II, InlineFunctionInfo &IFI, bool InsertLifetime = true);
196bool InlineFunction(CallSite CS, InlineFunctionInfo &IFI, bool InsertLifetime = true);
197
198} // End llvm namespace
199
200#endif
201