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      1 //===- CloneModule.cpp - Clone an entire module ---------------------------===//
      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 implements the CloneModule interface which makes a copy of an
     11 // entire module.
     12 //
     13 //===----------------------------------------------------------------------===//
     14 
     15 #include "llvm/Transforms/Utils/Cloning.h"
     16 #include "llvm/IR/Constant.h"
     17 #include "llvm/IR/DerivedTypes.h"
     18 #include "llvm/IR/Module.h"
     19 #include "llvm/Transforms/Utils/ValueMapper.h"
     20 using namespace llvm;
     21 
     22 /// CloneModule - Return an exact copy of the specified module.  This is not as
     23 /// easy as it might seem because we have to worry about making copies of global
     24 /// variables and functions, and making their (initializers and references,
     25 /// respectively) refer to the right globals.
     26 ///
     27 Module *llvm::CloneModule(const Module *M) {
     28   // Create the value map that maps things from the old module over to the new
     29   // module.
     30   ValueToValueMapTy VMap;
     31   return CloneModule(M, VMap);
     32 }
     33 
     34 Module *llvm::CloneModule(const Module *M, ValueToValueMapTy &VMap) {
     35   // First off, we need to create the new module.
     36   Module *New = new Module(M->getModuleIdentifier(), M->getContext());
     37   New->setDataLayout(M->getDataLayout());
     38   New->setTargetTriple(M->getTargetTriple());
     39   New->setModuleInlineAsm(M->getModuleInlineAsm());
     40 
     41   // Loop over all of the global variables, making corresponding globals in the
     42   // new module.  Here we add them to the VMap and to the new Module.  We
     43   // don't worry about attributes or initializers, they will come later.
     44   //
     45   for (Module::const_global_iterator I = M->global_begin(), E = M->global_end();
     46        I != E; ++I) {
     47     GlobalVariable *GV = new GlobalVariable(*New,
     48                                             I->getType()->getElementType(),
     49                                             I->isConstant(), I->getLinkage(),
     50                                             (Constant*) 0, I->getName(),
     51                                             (GlobalVariable*) 0,
     52                                             I->getThreadLocalMode(),
     53                                             I->getType()->getAddressSpace());
     54     GV->copyAttributesFrom(I);
     55     VMap[I] = GV;
     56   }
     57 
     58   // Loop over the functions in the module, making external functions as before
     59   for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I) {
     60     Function *NF =
     61       Function::Create(cast<FunctionType>(I->getType()->getElementType()),
     62                        I->getLinkage(), I->getName(), New);
     63     NF->copyAttributesFrom(I);
     64     VMap[I] = NF;
     65   }
     66 
     67   // Loop over the aliases in the module
     68   for (Module::const_alias_iterator I = M->alias_begin(), E = M->alias_end();
     69        I != E; ++I) {
     70     GlobalAlias *GA = new GlobalAlias(I->getType(), I->getLinkage(),
     71                                       I->getName(), NULL, New);
     72     GA->copyAttributesFrom(I);
     73     VMap[I] = GA;
     74   }
     75 
     76   // Now that all of the things that global variable initializer can refer to
     77   // have been created, loop through and copy the global variable referrers
     78   // over...  We also set the attributes on the global now.
     79   //
     80   for (Module::const_global_iterator I = M->global_begin(), E = M->global_end();
     81        I != E; ++I) {
     82     GlobalVariable *GV = cast<GlobalVariable>(VMap[I]);
     83     if (I->hasInitializer())
     84       GV->setInitializer(MapValue(I->getInitializer(), VMap));
     85   }
     86 
     87   // Similarly, copy over function bodies now...
     88   //
     89   for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I) {
     90     Function *F = cast<Function>(VMap[I]);
     91     if (!I->isDeclaration()) {
     92       Function::arg_iterator DestI = F->arg_begin();
     93       for (Function::const_arg_iterator J = I->arg_begin(); J != I->arg_end();
     94            ++J) {
     95         DestI->setName(J->getName());
     96         VMap[J] = DestI++;
     97       }
     98 
     99       SmallVector<ReturnInst*, 8> Returns;  // Ignore returns cloned.
    100       CloneFunctionInto(F, I, VMap, /*ModuleLevelChanges=*/true, Returns);
    101     }
    102   }
    103 
    104   // And aliases
    105   for (Module::const_alias_iterator I = M->alias_begin(), E = M->alias_end();
    106        I != E; ++I) {
    107     GlobalAlias *GA = cast<GlobalAlias>(VMap[I]);
    108     if (const Constant *C = I->getAliasee())
    109       GA->setAliasee(MapValue(C, VMap));
    110   }
    111 
    112   // And named metadata....
    113   for (Module::const_named_metadata_iterator I = M->named_metadata_begin(),
    114          E = M->named_metadata_end(); I != E; ++I) {
    115     const NamedMDNode &NMD = *I;
    116     NamedMDNode *NewNMD = New->getOrInsertNamedMetadata(NMD.getName());
    117     for (unsigned i = 0, e = NMD.getNumOperands(); i != e; ++i)
    118       NewNMD->addOperand(MapValue(NMD.getOperand(i), VMap));
    119   }
    120 
    121   return New;
    122 }
    123