text: //===- Cloning.h - Clone various parts of LLVM programs ---------*- C++ -*-===//
  //
  //                     The LLVM Compiler Infrastructure
  //
  // This file is distributed under the University of Illinois Open Source
  // License. See LICENSE.TXT for details.
  //
  //===----------------------------------------------------------------------===//
  //
  // This file defines various functions that are used to clone chunks of LLVM
  // code for various purposes.  This varies from copying whole modules into new
  // modules, to cloning functions with different arguments, to inlining
  // functions, to copying basic blocks to support loop unrolling or superblock
  // formation, etc.
  //
  //===----------------------------------------------------------------------===//
  
  #ifndef LLVM_TRANSFORMS_UTILS_CLONING_H
  #define LLVM_TRANSFORMS_UTILS_CLONING_H
  
  #include "llvm/ADT/ValueMap.h"
  #include "llvm/ADT/SmallVector.h"
  #include "llvm/ADT/Twine.h"
  #include "llvm/Support/ValueHandle.h"
  #include "llvm/Transforms/Utils/ValueMapper.h"
  
  namespace llvm {
  
  class Module;
  class Function;
  class Instruction;
  class Pass;
  class LPPassManager;
  class BasicBlock;
  class Value;
  class CallInst;
  class InvokeInst;
  class ReturnInst;
  class CallSite;
  class Trace;
  class CallGraph;
  class TargetData;
  class Loop;
  class LoopInfo;
  class AllocaInst;
  
  /// CloneModule - Return an exact copy of the specified module
  ///
  Module *CloneModule(const Module *M);
  Module *CloneModule(const Module *M, ValueToValueMapTy &VMap);
  
  /// ClonedCodeInfo - This struct can be used to capture information about code
  /// being cloned, while it is being cloned.
  struct ClonedCodeInfo {
    /// ContainsCalls - This is set to true if the cloned code contains a normal
    /// call instruction.
    bool ContainsCalls;
    
    /// ContainsDynamicAllocas - This is set to true if the cloned code contains
    /// a 'dynamic' alloca.  Dynamic allocas are allocas that are either not in
    /// the entry block or they are in the entry block but are not a constant
    /// size.
    bool ContainsDynamicAllocas;
    
    ClonedCodeInfo() : ContainsCalls(false), ContainsDynamicAllocas(false) {}
  };
  
  
  /// CloneBasicBlock - Return a copy of the specified basic block, but without
  /// embedding the block into a particular function.  The block returned is an
  /// exact copy of the specified basic block, without any remapping having been
  /// performed.  Because of this, this is only suitable for applications where
  /// the basic block will be inserted into the same function that it was cloned
  /// from (loop unrolling would use this, for example).
  ///
  /// Also, note that this function makes a direct copy of the basic block, and
  /// can thus produce illegal LLVM code.  In particular, it will copy any PHI
  /// nodes from the original block, even though there are no predecessors for the
  /// newly cloned block (thus, phi nodes will have to be updated).  Also, this
  /// block will branch to the old successors of the original block: these
  /// successors will have to have any PHI nodes updated to account for the new
  /// incoming edges.
  ///
  /// The correlation between instructions in the source and result basic blocks
  /// is recorded in the VMap map.
  ///
  /// If you have a particular suffix you'd like to use to add to any cloned
  /// names, specify it as the optional third parameter.
  ///
  /// If you would like the basic block to be auto-inserted into the end of a
  /// function, you can specify it as the optional fourth parameter.
  ///
  /// If you would like to collect additional information about the cloned
  /// function, you can specify a ClonedCodeInfo object with the optional fifth
  /// parameter.
  ///
  BasicBlock *CloneBasicBlock(const BasicBlock *BB,
                              ValueToValueMapTy &VMap,
                              const Twine &NameSuffix = "", Function *F = 0,
                              ClonedCodeInfo *CodeInfo = 0);
  
  /// CloneFunction - Return a copy of the specified function, but without
  /// embedding the function into another module.  Also, any references specified
  /// in the VMap are changed to refer to their mapped value instead of the
  /// original one.  If any of the arguments to the function are in the VMap,
  /// the arguments are deleted from the resultant function.  The VMap is
  /// updated to include mappings from all of the instructions and basicblocks in
  /// the function from their old to new values.  The final argument captures
  /// information about the cloned code if non-null.
  ///
  /// If ModuleLevelChanges is false, VMap contains no non-identity GlobalValue
  /// mappings.
  ///
  Function *CloneFunction(const Function *F,
                          ValueToValueMapTy &VMap,
                          bool ModuleLevelChanges,
                          ClonedCodeInfo *CodeInfo = 0);
  
  /// CloneFunction - Version of the function that doesn't need the VMap.
  ///
  inline Function *CloneFunction(const Function *F, ClonedCodeInfo *CodeInfo = 0){
    ValueToValueMapTy VMap;
    return CloneFunction(F, VMap, CodeInfo);
  }
  
  /// Clone OldFunc into NewFunc, transforming the old arguments into references
  /// to VMap values.  Note that if NewFunc already has basic blocks, the ones
  /// cloned into it will be added to the end of the function.  This function
  /// fills in a list of return instructions, and can optionally remap types
  /// and/or append the specified suffix to all values cloned.
  ///
  /// If ModuleLevelChanges is false, VMap contains no non-identity GlobalValue
  /// mappings.
  ///
  void CloneFunctionInto(Function *NewFunc, const Function *OldFunc,
                         ValueToValueMapTy &VMap,
                         bool ModuleLevelChanges,
                         SmallVectorImpl<ReturnInst*> &Returns,
                         const char *NameSuffix = "", 
                         ClonedCodeInfo *CodeInfo = 0,
                         ValueMapTypeRemapper *TypeMapper = 0);
  
  /// CloneAndPruneFunctionInto - This works exactly like CloneFunctionInto,
  /// except that it does some simple constant prop and DCE on the fly.  The
  /// effect of this is to copy significantly less code in cases where (for
  /// example) a function call with constant arguments is inlined, and those
  /// constant arguments cause a significant amount of code in the callee to be
  /// dead.  Since this doesn't produce an exactly copy of the input, it can't be
  /// used for things like CloneFunction or CloneModule.
  ///
  /// If ModuleLevelChanges is false, VMap contains no non-identity GlobalValue
  /// mappings.
  ///
  void CloneAndPruneFunctionInto(Function *NewFunc, const Function *OldFunc,
                                 ValueToValueMapTy &VMap,
                                 bool ModuleLevelChanges,
                                 SmallVectorImpl<ReturnInst*> &Returns,
                                 const char *NameSuffix = "", 
                                 ClonedCodeInfo *CodeInfo = 0,
                                 const TargetData *TD = 0,
                                 Instruction *TheCall = 0);
  
    
  /// InlineFunctionInfo - This class captures the data input to the
  /// InlineFunction call, and records the auxiliary results produced by it. 
  class InlineFunctionInfo {
  public:
    explicit InlineFunctionInfo(CallGraph *cg = 0, const TargetData *td = 0)
      : CG(cg), TD(td) {}
    
    /// CG - If non-null, InlineFunction will update the callgraph to reflect the
    /// changes it makes.
    CallGraph *CG;
    const TargetData *TD;
  
    /// StaticAllocas - InlineFunction fills this in with all static allocas that
    /// get copied into the caller.
    SmallVector<AllocaInst*, 4> StaticAllocas;
  
    /// InlinedCalls - InlineFunction fills this in with callsites that were
    /// inlined from the callee.  This is only filled in if CG is non-null.
    SmallVector<WeakVH, 8> InlinedCalls;
    
    void reset() {
      StaticAllocas.clear();
      InlinedCalls.clear();
    }
  };
    
  /// InlineFunction - This function inlines the called function into the basic
  /// block of the caller.  This returns false if it is not possible to inline
  /// this call.  The program is still in a well defined state if this occurs
  /// though.
  ///
  /// Note that this only does one level of inlining.  For example, if the
  /// instruction 'call B' is inlined, and 'B' calls 'C', then the call to 'C' now
  /// exists in the instruction stream.  Similarly this will inline a recursive
  /// function by one level.
  ///
  bool InlineFunction(CallInst *C, InlineFunctionInfo &IFI, bool InsertLifetime = true);
  bool InlineFunction(InvokeInst *II, InlineFunctionInfo &IFI, bool InsertLifetime = true);
  bool InlineFunction(CallSite CS, InlineFunctionInfo &IFI, bool InsertLifetime = true);
  
  } // End llvm namespace
  
  #endif
  