llvm/lib/Transforms/Utils/CloneModule.cpp

//===- CloneModule.cpp - Clone an entire module ---------------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the CloneModule interface which makes a copy of an
// entire module.
//
//===----------------------------------------------------------------------===//

#include "llvm/Transforms/Utils/Cloning.h"
#include "llvm/Module.h"
#include "llvm/DerivedTypes.h"
#include "llvm/SymbolTable.h"
#include "llvm/Constant.h"
#include "ValueMapper.h"
using namespace llvm;

/// CloneModule - Return an exact copy of the specified module.  This is not as
/// easy as it might seem because we have to worry about making copies of global
/// variables and functions, and making their (initializers and references,
/// respectively) refer to the right globals.
///
Module *llvm::CloneModule(const Module *M) {
  // First off, we need to create the new module...
  Module *New = new Module(M->getModuleIdentifier());
  New->setEndianness(M->getEndianness());
  New->setPointerSize(M->getPointerSize());
  New->setTargetTriple(M->getTargetTriple());
  New->setModuleInlineAsm(M->getModuleInlineAsm());

  // Copy all of the type symbol table entries over.
  const SymbolTable &SymTab = M->getSymbolTable();
  SymbolTable::type_const_iterator TypeI = SymTab.type_begin();
  SymbolTable::type_const_iterator TypeE = SymTab.type_end();
  for (; TypeI != TypeE; ++TypeI)
    New->addTypeName(TypeI->first, TypeI->second);
  
  // Copy all of the dependent libraries over.
  for (Module::lib_iterator I = M->lib_begin(), E = M->lib_end(); I != E; ++I)
    New->addLibrary(*I);

  // Create the value map that maps things from the old module over to the new
  // module.
  std::map<const Value*, Value*> ValueMap;

  // Loop over all of the global variables, making corresponding globals in the
  // new module.  Here we add them to the ValueMap and to the new Module.  We
  // don't worry about attributes or initializers, they will come later.
  //
  for (Module::const_global_iterator I = M->global_begin(), E = M->global_end();
       I != E; ++I)
    ValueMap[I] = new GlobalVariable(I->getType()->getElementType(), false,
                                     GlobalValue::ExternalLinkage, 0,
                                     I->getName(), New);

  // Loop over the functions in the module, making external functions as before
  for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I) {
    Function *NF =
      new Function(cast<FunctionType>(I->getType()->getElementType()),
                   GlobalValue::ExternalLinkage, I->getName(), New);
    NF->setCallingConv(I->getCallingConv());
    ValueMap[I]= NF;
  }

  // Now that all of the things that global variable initializer can refer to
  // have been created, loop through and copy the global variable referrers
  // over...  We also set the attributes on the global now.
  //
  for (Module::const_global_iterator I = M->global_begin(), E = M->global_end();
       I != E; ++I) {
    GlobalVariable *GV = cast<GlobalVariable>(ValueMap[I]);
    if (I->hasInitializer())
      GV->setInitializer(cast<Constant>(MapValue(I->getInitializer(),
                                                 ValueMap)));
    GV->setLinkage(I->getLinkage());
  }

  // Similarly, copy over function bodies now...
  //
  for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I) {
    Function *F = cast<Function>(ValueMap[I]);
    if (!I->isExternal()) {
      Function::arg_iterator DestI = F->arg_begin();
      for (Function::const_arg_iterator J = I->arg_begin(); J != I->arg_end();
           ++J) {
        DestI->setName(J->getName());
        ValueMap[J] = DestI++;
      }

      std::vector<ReturnInst*> Returns;  // Ignore returns cloned...
      CloneFunctionInto(F, I, ValueMap, Returns);
    }

    F->setLinkage(I->getLinkage());
  }

  return New;
}

// vim: sw=2