lib/Transforms/Utils/CloneModule.cpp

   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 }