CloneModule.cpp revision cd81d94322a39503e4a3e87b6ee03d4fcb3465fb 
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"
20using 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///
27Module *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
34Module *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*) nullptr, I->getName(),
51                                            (GlobalVariable*) nullptr,
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    auto *PTy = cast<PointerType>(I->getType());
71    auto *GA =
72        GlobalAlias::create(PTy->getElementType(), PTy->getAddressSpace(),
73                            I->getLinkage(), I->getName(), New);
74    GA->copyAttributesFrom(I);
75    VMap[I] = GA;
76  }
77
78  // Now that all of the things that global variable initializer can refer to
79  // have been created, loop through and copy the global variable referrers
80  // over...  We also set the attributes on the global now.
81  //
82  for (Module::const_global_iterator I = M->global_begin(), E = M->global_end();
83       I != E; ++I) {
84    GlobalVariable *GV = cast<GlobalVariable>(VMap[I]);
85    if (I->hasInitializer())
86      GV->setInitializer(MapValue(I->getInitializer(), VMap));
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
106  // And aliases
107  for (Module::const_alias_iterator I = M->alias_begin(), E = M->alias_end();
108       I != E; ++I) {
109    GlobalAlias *GA = cast<GlobalAlias>(VMap[I]);
110    if (const Constant *C = I->getAliasee())
111      GA->setAliasee(cast<GlobalObject>(MapValue(C, VMap)));
112  }
113
114  // And named metadata....
115  for (Module::const_named_metadata_iterator I = M->named_metadata_begin(),
116         E = M->named_metadata_end(); I != E; ++I) {
117    const NamedMDNode &NMD = *I;
118    NamedMDNode *NewNMD = New->getOrInsertNamedMetadata(NMD.getName());
119    for (unsigned i = 0, e = NMD.getNumOperands(); i != e; ++i)
120      NewNMD->addOperand(MapValue(NMD.getOperand(i), VMap));
121  }
122
123  return New;
124}
125