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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/Module.h"
     17 #include "llvm/DerivedTypes.h"
     18 #include "llvm/Constant.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   // Copy all of the dependent libraries over.
     42   for (Module::lib_iterator I = M->lib_begin(), E = M->lib_end(); I != E; ++I)
     43     New->addLibrary(*I);
     44 
     45   // Loop over all of the global variables, making corresponding globals in the
     46   // new module.  Here we add them to the VMap and to the new Module.  We
     47   // don't worry about attributes or initializers, they will come later.
     48   //
     49   for (Module::const_global_iterator I = M->global_begin(), E = M->global_end();
     50        I != E; ++I) {
     51     GlobalVariable *GV = new GlobalVariable(*New,
     52                                             I->getType()->getElementType(),
     53                                             false,
     54                                             GlobalValue::ExternalLinkage, 0,
     55                                             I->getName());
     56     GV->setAlignment(I->getAlignment());
     57     VMap[I] = GV;
     58   }
     59 
     60   // Loop over the functions in the module, making external functions as before
     61   for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I) {
     62     Function *NF =
     63       Function::Create(cast<FunctionType>(I->getType()->getElementType()),
     64                        GlobalValue::ExternalLinkage, I->getName(), New);
     65     NF->copyAttributesFrom(I);
     66     VMap[I] = NF;
     67   }
     68 
     69   // Loop over the aliases in the module
     70   for (Module::const_alias_iterator I = M->alias_begin(), E = M->alias_end();
     71        I != E; ++I)
     72     VMap[I] = new GlobalAlias(I->getType(), GlobalAlias::ExternalLinkage,
     73                                   I->getName(), NULL, New);
     74 
     75   // Now that all of the things that global variable initializer can refer to
     76   // have been created, loop through and copy the global variable referrers
     77   // over...  We also set the attributes on the global now.
     78   //
     79   for (Module::const_global_iterator I = M->global_begin(), E = M->global_end();
     80        I != E; ++I) {
     81     GlobalVariable *GV = cast<GlobalVariable>(VMap[I]);
     82     if (I->hasInitializer())
     83       GV->setInitializer(MapValue(I->getInitializer(), VMap));
     84     GV->setLinkage(I->getLinkage());
     85     GV->setThreadLocal(I->isThreadLocal());
     86     GV->setConstant(I->isConstant());
     87   }
     88 
     89   // Similarly, copy over function bodies now...
     90   //
     91   for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I) {
     92     Function *F = cast<Function>(VMap[I]);
     93     if (!I->isDeclaration()) {
     94       Function::arg_iterator DestI = F->arg_begin();
     95       for (Function::const_arg_iterator J = I->arg_begin(); J != I->arg_end();
     96            ++J) {
     97         DestI->setName(J->getName());
     98         VMap[J] = DestI++;
     99       }
    100 
    101       SmallVector<ReturnInst*, 8> Returns;  // Ignore returns cloned.
    102       CloneFunctionInto(F, I, VMap, /*ModuleLevelChanges=*/true, Returns);
    103     }
    104 
    105     F->setLinkage(I->getLinkage());
    106   }
    107 
    108   // And aliases
    109   for (Module::const_alias_iterator I = M->alias_begin(), E = M->alias_end();
    110        I != E; ++I) {
    111     GlobalAlias *GA = cast<GlobalAlias>(VMap[I]);
    112     GA->setLinkage(I->getLinkage());
    113     if (const Constant *C = I->getAliasee())
    114       GA->setAliasee(MapValue(C, VMap));
    115   }
    116 
    117   // And named metadata....
    118   for (Module::const_named_metadata_iterator I = M->named_metadata_begin(),
    119          E = M->named_metadata_end(); I != E; ++I) {
    120     const NamedMDNode &NMD = *I;
    121     NamedMDNode *NewNMD = New->getOrInsertNamedMetadata(NMD.getName());
    122     for (unsigned i = 0, e = NMD.getNumOperands(); i != e; ++i)
    123       NewNMD->addOperand(MapValue(NMD.getOperand(i), VMap));
    124   }
    125 
    126   return New;
    127 }
    128