LLVM API Documentation

Cloning.h

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00001 //===- Cloning.h - Clone various parts of LLVM programs ---------*- C++ -*-===//
00002 //
00003 //                     The LLVM Compiler Infrastructure
00004 //
00005 // This file was developed by the LLVM research group and is distributed under
00006 // the University of Illinois Open Source License. See LICENSE.TXT for details.
00007 //
00008 //===----------------------------------------------------------------------===//
00009 //
00010 // This file defines various functions that are used to clone chunks of LLVM
00011 // code for various purposes.  This varies from copying whole modules into new
00012 // modules, to cloning functions with different arguments, to inlining
00013 // functions, to copying basic blocks to support loop unrolling or superblock
00014 // formation, etc.
00015 //
00016 //===----------------------------------------------------------------------===//
00017 
00018 #ifndef LLVM_TRANSFORMS_UTILS_CLONING_H
00019 #define LLVM_TRANSFORMS_UTILS_CLONING_H
00020 
00021 #include <vector>
00022 #include <map>
00023 
00024 namespace llvm {
00025 
00026 class Module;
00027 class Function;
00028 class BasicBlock;
00029 class Value;
00030 class CallInst;
00031 class InvokeInst;
00032 class ReturnInst;
00033 class CallSite;
00034 class Trace;
00035 class CallGraph;
00036 
00037 /// CloneModule - Return an exact copy of the specified module
00038 ///
00039 Module *CloneModule(const Module *M);
00040 
00041 /// ClonedCodeInfo - This struct can be used to capture information about code
00042 /// being cloned, while it is being cloned.
00043 struct ClonedCodeInfo {
00044   /// ContainsCalls - This is set to true if the cloned code contains a normal
00045   /// call instruction.
00046   bool ContainsCalls;
00047   
00048   /// ContainsUnwinds - This is set to true if the cloned code contains an
00049   /// unwind instruction.
00050   bool ContainsUnwinds;
00051   
00052   /// ContainsDynamicAllocas - This is set to true if the cloned code contains
00053   /// a 'dynamic' alloca.  Dynamic allocas are allocas that are either not in
00054   /// the entry block or they are in the entry block but are not a constant
00055   /// size.
00056   bool ContainsDynamicAllocas;
00057   
00058   ClonedCodeInfo() {
00059     ContainsCalls = false;
00060     ContainsUnwinds = false;
00061     ContainsDynamicAllocas = false;
00062   }
00063 };
00064 
00065 
00066 /// CloneBasicBlock - Return a copy of the specified basic block, but without
00067 /// embedding the block into a particular function.  The block returned is an
00068 /// exact copy of the specified basic block, without any remapping having been
00069 /// performed.  Because of this, this is only suitable for applications where
00070 /// the basic block will be inserted into the same function that it was cloned
00071 /// from (loop unrolling would use this, for example).
00072 ///
00073 /// Also, note that this function makes a direct copy of the basic block, and
00074 /// can thus produce illegal LLVM code.  In particular, it will copy any PHI
00075 /// nodes from the original block, even though there are no predecessors for the
00076 /// newly cloned block (thus, phi nodes will have to be updated).  Also, this
00077 /// block will branch to the old successors of the original block: these
00078 /// successors will have to have any PHI nodes updated to account for the new
00079 /// incoming edges.
00080 ///
00081 /// The correlation between instructions in the source and result basic blocks
00082 /// is recorded in the ValueMap map.
00083 ///
00084 /// If you have a particular suffix you'd like to use to add to any cloned
00085 /// names, specify it as the optional third parameter.
00086 ///
00087 /// If you would like the basic block to be auto-inserted into the end of a
00088 /// function, you can specify it as the optional fourth parameter.
00089 ///
00090 /// If you would like to collect additional information about the cloned
00091 /// function, you can specify a ClonedCodeInfo object with the optional fifth
00092 /// parameter.
00093 ///
00094 BasicBlock *CloneBasicBlock(const BasicBlock *BB,
00095                             std::map<const Value*, Value*> &ValueMap,
00096                             const char *NameSuffix = "", Function *F = 0,
00097                             ClonedCodeInfo *CodeInfo = 0);
00098 
00099 
00100 /// CloneFunction - Return a copy of the specified function, but without
00101 /// embedding the function into another module.  Also, any references specified
00102 /// in the ValueMap are changed to refer to their mapped value instead of the
00103 /// original one.  If any of the arguments to the function are in the ValueMap,
00104 /// the arguments are deleted from the resultant function.  The ValueMap is
00105 /// updated to include mappings from all of the instructions and basicblocks in
00106 /// the function from their old to new values.  The final argument captures
00107 /// information about the cloned code if non-null.
00108 ///
00109 Function *CloneFunction(const Function *F,
00110                         std::map<const Value*, Value*> &ValueMap,
00111                         ClonedCodeInfo *CodeInfo = 0);
00112 
00113 /// CloneFunction - Version of the function that doesn't need the ValueMap.
00114 ///
00115 inline Function *CloneFunction(const Function *F, ClonedCodeInfo *CodeInfo = 0){
00116   std::map<const Value*, Value*> ValueMap;
00117   return CloneFunction(F, ValueMap, CodeInfo);
00118 }
00119 
00120 /// Clone OldFunc into NewFunc, transforming the old arguments into references
00121 /// to ArgMap values.  Note that if NewFunc already has basic blocks, the ones
00122 /// cloned into it will be added to the end of the function.  This function
00123 /// fills in a list of return instructions, and can optionally append the
00124 /// specified suffix to all values cloned.
00125 ///
00126 void CloneFunctionInto(Function *NewFunc, const Function *OldFunc,
00127                        std::map<const Value*, Value*> &ValueMap,
00128                        std::vector<ReturnInst*> &Returns,
00129                        const char *NameSuffix = "", 
00130                        ClonedCodeInfo *CodeInfo = 0);
00131 
00132 
00133 /// CloneTraceInto - Clone T into NewFunc. Original<->clone mapping is
00134 /// saved in ValueMap.
00135 ///
00136 void CloneTraceInto(Function *NewFunc, Trace &T,
00137                     std::map<const Value*, Value*> &ValueMap,
00138                     const char *NameSuffix);
00139 
00140 /// CloneTrace - Returns a copy of the specified trace.
00141 /// It takes a vector of basic blocks clones the basic blocks, removes internal
00142 /// phi nodes, adds it to the same function as the original (although there is
00143 /// no jump to it) and returns the new vector of basic blocks.
00144 std::vector<BasicBlock *> CloneTrace(const std::vector<BasicBlock*> &origTrace);
00145 
00146 /// InlineFunction - This function inlines the called function into the basic
00147 /// block of the caller.  This returns false if it is not possible to inline
00148 /// this call.  The program is still in a well defined state if this occurs
00149 /// though.
00150 ///
00151 /// Note that this only does one level of inlining.  For example, if the
00152 /// instruction 'call B' is inlined, and 'B' calls 'C', then the call to 'C' now
00153 /// exists in the instruction stream.  Similiarly this will inline a recursive
00154 /// function by one level.
00155 ///
00156 /// If a non-null callgraph pointer is provided, these functions update the
00157 /// CallGraph to represent the program after inlining.
00158 ///
00159 bool InlineFunction(CallInst *C, CallGraph *CG = 0);
00160 bool InlineFunction(InvokeInst *II, CallGraph *CG = 0);
00161 bool InlineFunction(CallSite CS, CallGraph *CG = 0);
00162 
00163 } // End llvm namespace
00164 
00165 #endif