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/TypeSymbolTable.h"
  19 #include "llvm/Constant.h"
  20 #include "llvm/Transforms/Utils/ValueMapper.h"
  21 using namespace llvm;
  22
  23 /// CloneModule - Return an exact copy of the specified module.  This is not as
  24 /// easy as it might seem because we have to worry about making copies of global
  25 /// variables and functions, and making their (initializers and references,
  26 /// respectively) refer to the right globals.
  27 ///
  28 Module *llvm::CloneModule(const Module *M) {
  29   // Create the value map that maps things from the old module over to the new
  30   // module.
  31   DenseMap<const Value*, Value*> ValueMap;
  32   return CloneModule(M, ValueMap);
  33 }
  34
  35 Module *llvm::CloneModule(const Module *M,
  36                           DenseMap<const Value*, Value*> &ValueMap) {
  37   // First off, we need to create the new module...
  38   Module *New = new Module(M->getModuleIdentifier(), M->getContext());
  39   New->setDataLayout(M->getDataLayout());
  40   New->setTargetTriple(M->getTargetTriple());
  41   New->setModuleInlineAsm(M->getModuleInlineAsm());
  42
  43   // Copy all of the type symbol table entries over.
  44   const TypeSymbolTable &TST = M->getTypeSymbolTable();
  45   for (TypeSymbolTable::const_iterator TI = TST.begin(), TE = TST.end();
  46        TI != TE; ++TI)
  47     New->addTypeName(TI->first, TI->second);
  48
  49   // Copy all of the dependent libraries over.
  50   for (Module::lib_iterator I = M->lib_begin(), E = M->lib_end(); I != E; ++I)
  51     New->addLibrary(*I);
  52
  53   // Loop over all of the global variables, making corresponding globals in the
  54   // new module.  Here we add them to the ValueMap and to the new Module.  We
  55   // don't worry about attributes or initializers, they will come later.
  56   //
  57   for (Module::const_global_iterator I = M->global_begin(), E = M->global_end();
  58        I != E; ++I) {
  59     GlobalVariable *GV = new GlobalVariable(*New,
  60                                             I->getType()->getElementType(),
  61                                             false,
  62                                             GlobalValue::ExternalLinkage, 0,
  63                                             I->getName());
  64     GV->setAlignment(I->getAlignment());
  65     ValueMap[I] = GV;
  66   }
  67
  68   // Loop over the functions in the module, making external functions as before
  69   for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I) {
  70     Function *NF =
  71       Function::Create(cast<FunctionType>(I->getType()->getElementType()),
  72                        GlobalValue::ExternalLinkage, I->getName(), New);
  73     NF->copyAttributesFrom(I);
  74     ValueMap[I] = NF;
  75   }
  76
  77   // Loop over the aliases in the module
  78   for (Module::const_alias_iterator I = M->alias_begin(), E = M->alias_end();
  79        I != E; ++I)
  80     ValueMap[I] = new GlobalAlias(I->getType(), GlobalAlias::ExternalLinkage,
  81                                   I->getName(), NULL, New);
  82
  83   // Now that all of the things that global variable initializer can refer to
  84   // have been created, loop through and copy the global variable referrers
  85   // over...  We also set the attributes on the global now.
  86   //
  87   for (Module::const_global_iterator I = M->global_begin(), E = M->global_end();
  88        I != E; ++I) {
  89     GlobalVariable *GV = cast<GlobalVariable>(ValueMap[I]);
  90     if (I->hasInitializer())
  91       GV->setInitializer(cast<Constant>(MapValue(I->getInitializer(),
  92                                                  ValueMap,
  93                                                  M->getContext())));
  94     GV->setLinkage(I->getLinkage());
  95     GV->setThreadLocal(I->isThreadLocal());
  96     GV->setConstant(I->isConstant());
  97   }
  98
  99   // Similarly, copy over function bodies now...
 100   //
 101   for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I) {
 102     Function *F = cast<Function>(ValueMap[I]);
 103     if (!I->isDeclaration()) {
 104       Function::arg_iterator DestI = F->arg_begin();
 105       for (Function::const_arg_iterator J = I->arg_begin(); J != I->arg_end();
 106            ++J) {
 107         DestI->setName(J->getName());
 108         ValueMap[J] = DestI++;
 109       }
 110
 111       SmallVector<ReturnInst*, 8> Returns;  // Ignore returns cloned.
 112       CloneFunctionInto(F, I, ValueMap, Returns);
 113     }
 114
 115     F->setLinkage(I->getLinkage());
 116   }
 117
 118   // And aliases
 119   for (Module::const_alias_iterator I = M->alias_begin(), E = M->alias_end();
 120        I != E; ++I) {
 121     GlobalAlias *GA = cast<GlobalAlias>(ValueMap[I]);
 122     GA->setLinkage(I->getLinkage());
 123     if (const Constant* C = I->getAliasee())
 124       GA->setAliasee(cast<Constant>(MapValue(C, ValueMap, M->getContext())));
 125   }
 126
 127   return New;
 128 }