Cloning.h revision d24397a9319a41e80169f572ad274a711f41d64e 
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/ValueMap.h"
22#include "llvm/ADT/SmallVector.h"
23#include "llvm/ADT/Twine.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 TargetData;
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  /// ContainsUnwinds - This is set to true if the cloned code contains an
60  /// unwind instruction.
61  bool ContainsUnwinds;
62
63  /// ContainsDynamicAllocas - This is set to true if the cloned code contains
64  /// a 'dynamic' alloca.  Dynamic allocas are allocas that are either not in
65  /// the entry block or they are in the entry block but are not a constant
66  /// size.
67  bool ContainsDynamicAllocas;
68
69  ClonedCodeInfo() {
70    ContainsCalls = false;
71    ContainsUnwinds = false;
72    ContainsDynamicAllocas = false;
73  }
74};
75
76
77/// CloneBasicBlock - Return a copy of the specified basic block, but without
78/// embedding the block into a particular function.  The block returned is an
79/// exact copy of the specified basic block, without any remapping having been
80/// performed.  Because of this, this is only suitable for applications where
81/// the basic block will be inserted into the same function that it was cloned
82/// from (loop unrolling would use this, for example).
83///
84/// Also, note that this function makes a direct copy of the basic block, and
85/// can thus produce illegal LLVM code.  In particular, it will copy any PHI
86/// nodes from the original block, even though there are no predecessors for the
87/// newly cloned block (thus, phi nodes will have to be updated).  Also, this
88/// block will branch to the old successors of the original block: these
89/// successors will have to have any PHI nodes updated to account for the new
90/// incoming edges.
91///
92/// The correlation between instructions in the source and result basic blocks
93/// is recorded in the VMap map.
94///
95/// If you have a particular suffix you'd like to use to add to any cloned
96/// names, specify it as the optional third parameter.
97///
98/// If you would like the basic block to be auto-inserted into the end of a
99/// function, you can specify it as the optional fourth parameter.
100///
101/// If you would like to collect additional information about the cloned
102/// function, you can specify a ClonedCodeInfo object with the optional fifth
103/// parameter.
104///
105BasicBlock *CloneBasicBlock(const BasicBlock *BB,
106                            ValueToValueMapTy &VMap,
107                            const Twine &NameSuffix = "", Function *F = 0,
108                            ClonedCodeInfo *CodeInfo = 0);
109
110/// CloneFunction - Return a copy of the specified function, but without
111/// embedding the function into another module.  Also, any references specified
112/// in the VMap are changed to refer to their mapped value instead of the
113/// original one.  If any of the arguments to the function are in the VMap,
114/// the arguments are deleted from the resultant function.  The VMap is
115/// updated to include mappings from all of the instructions and basicblocks in
116/// the function from their old to new values.  The final argument captures
117/// information about the cloned code if non-null.
118///
119/// If ModuleLevelChanges is false, VMap contains no non-identity GlobalValue
120/// mappings.
121///
122Function *CloneFunction(const Function *F,
123                        ValueToValueMapTy &VMap,
124                        bool ModuleLevelChanges,
125                        ClonedCodeInfo *CodeInfo = 0);
126
127/// CloneFunction - Version of the function that doesn't need the VMap.
128///
129inline Function *CloneFunction(const Function *F, ClonedCodeInfo *CodeInfo = 0){
130  ValueToValueMapTy VMap;
131  return CloneFunction(F, VMap, CodeInfo);
132}
133
134/// Clone OldFunc into NewFunc, transforming the old arguments into references
135/// to VMap values.  Note that if NewFunc already has basic blocks, the ones
136/// cloned into it will be added to the end of the function.  This function
137/// fills in a list of return instructions, and can optionally remap types
138/// and/or append the specified suffix to all values cloned.
139///
140/// If ModuleLevelChanges is false, VMap contains no non-identity GlobalValue
141/// mappings.
142///
143void CloneFunctionInto(Function *NewFunc, const Function *OldFunc,
144                       ValueToValueMapTy &VMap,
145                       bool ModuleLevelChanges,
146                       SmallVectorImpl<ReturnInst*> &Returns,
147                       const char *NameSuffix = "",
148                       ClonedCodeInfo *CodeInfo = 0,
149                       ValueMapTypeRemapper *TypeMapper = 0);
150
151/// CloneAndPruneFunctionInto - This works exactly like CloneFunctionInto,
152/// except that it does some simple constant prop and DCE on the fly.  The
153/// effect of this is to copy significantly less code in cases where (for
154/// example) a function call with constant arguments is inlined, and those
155/// constant arguments cause a significant amount of code in the callee to be
156/// dead.  Since this doesn't produce an exactly copy of the input, it can't be
157/// used for things like CloneFunction or CloneModule.
158///
159/// If ModuleLevelChanges is false, VMap contains no non-identity GlobalValue
160/// mappings.
161///
162void CloneAndPruneFunctionInto(Function *NewFunc, const Function *OldFunc,
163                               ValueToValueMapTy &VMap,
164                               bool ModuleLevelChanges,
165                               SmallVectorImpl<ReturnInst*> &Returns,
166                               const char *NameSuffix = "",
167                               ClonedCodeInfo *CodeInfo = 0,
168                               const TargetData *TD = 0,
169                               Instruction *TheCall = 0);
170
171
172/// InlineFunctionInfo - This class captures the data input to the
173/// InlineFunction call, and records the auxiliary results produced by it.
174class InlineFunctionInfo {
175public:
176  explicit InlineFunctionInfo(CallGraph *cg = 0, const TargetData *td = 0)
177    : CG(cg), TD(td) {}
178
179  /// CG - If non-null, InlineFunction will update the callgraph to reflect the
180  /// changes it makes.
181  CallGraph *CG;
182  const TargetData *TD;
183
184  /// StaticAllocas - InlineFunction fills this in with all static allocas that
185  /// get copied into the caller.
186  SmallVector<AllocaInst*, 4> StaticAllocas;
187
188  /// InlinedCalls - InlineFunction fills this in with callsites that were
189  /// inlined from the callee.  This is only filled in if CG is non-null.
190  SmallVector<WeakVH, 8> InlinedCalls;
191
192  void reset() {
193    StaticAllocas.clear();
194    InlinedCalls.clear();
195  }
196};
197
198/// InlineFunction - This function inlines the called function into the basic
199/// block of the caller.  This returns false if it is not possible to inline
200/// this call.  The program is still in a well defined state if this occurs
201/// though.
202///
203/// Note that this only does one level of inlining.  For example, if the
204/// instruction 'call B' is inlined, and 'B' calls 'C', then the call to 'C' now
205/// exists in the instruction stream.  Similarly this will inline a recursive
206/// function by one level.
207///
208bool InlineFunction(CallInst *C, InlineFunctionInfo &IFI);
209bool InlineFunction(InvokeInst *II, InlineFunctionInfo &IFI);
210bool InlineFunction(CallSite CS, InlineFunctionInfo &IFI);
211
212} // End llvm namespace
213
214#endif
215