LLVM  7.0.0svn
CloneModule.cpp
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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/IR/Constant.h"
16 #include "llvm/IR/DerivedTypes.h"
17 #include "llvm/IR/Module.h"
20 using namespace llvm;
21 
22 static void copyComdat(GlobalObject *Dst, const GlobalObject *Src) {
23  const Comdat *SC = Src->getComdat();
24  if (!SC)
25  return;
26  Comdat *DC = Dst->getParent()->getOrInsertComdat(SC->getName());
28  Dst->setComdat(DC);
29 }
30 
31 /// This is not as easy as it might seem because we have to worry about making
32 /// copies of global variables and functions, and making their (initializers and
33 /// references, respectively) refer to the right globals.
34 ///
35 std::unique_ptr<Module> llvm::CloneModule(const Module *M) {
36  // Create the value map that maps things from the old module over to the new
37  // module.
38  ValueToValueMapTy VMap;
39  return CloneModule(M, VMap);
40 }
41 
42 std::unique_ptr<Module> llvm::CloneModule(const Module *M,
43  ValueToValueMapTy &VMap) {
44  return CloneModule(M, VMap, [](const GlobalValue *GV) { return true; });
45 }
46 
47 std::unique_ptr<Module> llvm::CloneModule(
48  const Module *M, ValueToValueMapTy &VMap,
49  function_ref<bool(const GlobalValue *)> ShouldCloneDefinition) {
50  // First off, we need to create the new module.
51  std::unique_ptr<Module> New =
52  llvm::make_unique<Module>(M->getModuleIdentifier(), M->getContext());
53  New->setDataLayout(M->getDataLayout());
54  New->setTargetTriple(M->getTargetTriple());
55  New->setModuleInlineAsm(M->getModuleInlineAsm());
56 
57  // Loop over all of the global variables, making corresponding globals in the
58  // new module. Here we add them to the VMap and to the new Module. We
59  // don't worry about attributes or initializers, they will come later.
60  //
62  I != E; ++I) {
63  GlobalVariable *GV = new GlobalVariable(*New,
64  I->getValueType(),
65  I->isConstant(), I->getLinkage(),
66  (Constant*) nullptr, I->getName(),
67  (GlobalVariable*) nullptr,
68  I->getThreadLocalMode(),
69  I->getType()->getAddressSpace());
70  GV->copyAttributesFrom(&*I);
71  VMap[&*I] = GV;
72  }
73 
74  // Loop over the functions in the module, making external functions as before
75  for (const Function &I : *M) {
76  Function *NF = Function::Create(cast<FunctionType>(I.getValueType()),
77  I.getLinkage(), I.getName(), New.get());
78  NF->copyAttributesFrom(&I);
79  VMap[&I] = NF;
80  }
81 
82  // Loop over the aliases in the module
83  for (Module::const_alias_iterator I = M->alias_begin(), E = M->alias_end();
84  I != E; ++I) {
85  if (!ShouldCloneDefinition(&*I)) {
86  // An alias cannot act as an external reference, so we need to create
87  // either a function or a global variable depending on the value type.
88  // FIXME: Once pointee types are gone we can probably pick one or the
89  // other.
90  GlobalValue *GV;
91  if (I->getValueType()->isFunctionTy())
92  GV = Function::Create(cast<FunctionType>(I->getValueType()),
93  GlobalValue::ExternalLinkage, I->getName(),
94  New.get());
95  else
96  GV = new GlobalVariable(
97  *New, I->getValueType(), false, GlobalValue::ExternalLinkage,
98  nullptr, I->getName(), nullptr,
99  I->getThreadLocalMode(), I->getType()->getAddressSpace());
100  VMap[&*I] = GV;
101  // We do not copy attributes (mainly because copying between different
102  // kinds of globals is forbidden), but this is generally not required for
103  // correctness.
104  continue;
105  }
106  auto *GA = GlobalAlias::create(I->getValueType(),
107  I->getType()->getPointerAddressSpace(),
108  I->getLinkage(), I->getName(), New.get());
109  GA->copyAttributesFrom(&*I);
110  VMap[&*I] = GA;
111  }
112 
113  // Now that all of the things that global variable initializer can refer to
114  // have been created, loop through and copy the global variable referrers
115  // over... We also set the attributes on the global now.
116  //
117  for (Module::const_global_iterator I = M->global_begin(), E = M->global_end();
118  I != E; ++I) {
119  if (I->isDeclaration())
120  continue;
121 
122  GlobalVariable *GV = cast<GlobalVariable>(VMap[&*I]);
123  if (!ShouldCloneDefinition(&*I)) {
124  // Skip after setting the correct linkage for an external reference.
126  continue;
127  }
128  if (I->hasInitializer())
129  GV->setInitializer(MapValue(I->getInitializer(), VMap));
130 
132  I->getAllMetadata(MDs);
133  for (auto MD : MDs)
134  GV->addMetadata(MD.first,
135  *MapMetadata(MD.second, VMap, RF_MoveDistinctMDs));
136 
137  copyComdat(GV, &*I);
138  }
139 
140  // Similarly, copy over function bodies now...
141  //
142  for (const Function &I : *M) {
143  if (I.isDeclaration())
144  continue;
145 
146  Function *F = cast<Function>(VMap[&I]);
147  if (!ShouldCloneDefinition(&I)) {
148  // Skip after setting the correct linkage for an external reference.
150  // Personality function is not valid on a declaration.
151  F->setPersonalityFn(nullptr);
152  continue;
153  }
154 
155  Function::arg_iterator DestI = F->arg_begin();
156  for (Function::const_arg_iterator J = I.arg_begin(); J != I.arg_end();
157  ++J) {
158  DestI->setName(J->getName());
159  VMap[&*J] = &*DestI++;
160  }
161 
162  SmallVector<ReturnInst *, 8> Returns; // Ignore returns cloned.
163  CloneFunctionInto(F, &I, VMap, /*ModuleLevelChanges=*/true, Returns);
164 
165  if (I.hasPersonalityFn())
166  F->setPersonalityFn(MapValue(I.getPersonalityFn(), VMap));
167 
168  copyComdat(F, &I);
169  }
170 
171  // And aliases
172  for (Module::const_alias_iterator I = M->alias_begin(), E = M->alias_end();
173  I != E; ++I) {
174  // We already dealt with undefined aliases above.
175  if (!ShouldCloneDefinition(&*I))
176  continue;
177  GlobalAlias *GA = cast<GlobalAlias>(VMap[&*I]);
178  if (const Constant *C = I->getAliasee())
179  GA->setAliasee(MapValue(C, VMap));
180  }
181 
182  // And named metadata....
183  for (Module::const_named_metadata_iterator I = M->named_metadata_begin(),
184  E = M->named_metadata_end(); I != E; ++I) {
185  const NamedMDNode &NMD = *I;
186  NamedMDNode *NewNMD = New->getOrInsertNamedMetadata(NMD.getName());
187  for (unsigned i = 0, e = NMD.getNumOperands(); i != e; ++i)
188  NewNMD->addOperand(MapMetadata(NMD.getOperand(i), VMap));
189  }
190 
191  return New;
192 }
193 
194 extern "C" {
195 
197  return wrap(CloneModule(unwrap(M)).release());
198 }
199 
200 }
uint64_t CallInst * C
const std::string & getTargetTriple() const
Get the target triple which is a string describing the target host.
Definition: Module.h:233
This class represents an incoming formal argument to a Function.
Definition: Argument.h:30
MDNode * getOperand(unsigned i) const
Definition: Metadata.cpp:1073
Compute iterated dominance frontiers using a linear time algorithm.
Definition: AllocatorList.h:24
struct LLVMOpaqueModule * LLVMModuleRef
The top-level container for all other LLVM Intermediate Representation (IR) objects.
Definition: Types.h:62
A Module instance is used to store all the information related to an LLVM module. ...
Definition: Module.h:63
void addOperand(MDNode *M)
Definition: Metadata.cpp:1079
An efficient, type-erasing, non-owning reference to a callable.
Definition: STLExtras.h:89
Externally visible function.
Definition: GlobalValue.h:49
F(f)
Metadata * MapMetadata(const Metadata *MD, ValueToValueMapTy &VM, RemapFlags Flags=RF_None, ValueMapTypeRemapper *TypeMapper=nullptr, ValueMaterializer *Materializer=nullptr)
Lookup or compute a mapping for a piece of metadata.
Definition: ValueMapper.h:228
A tuple of MDNodes.
Definition: Metadata.h:1323
void CloneFunctionInto(Function *NewFunc, const Function *OldFunc, ValueToValueMapTy &VMap, bool ModuleLevelChanges, SmallVectorImpl< ReturnInst *> &Returns, const char *NameSuffix="", ClonedCodeInfo *CodeInfo=nullptr, ValueMapTypeRemapper *TypeMapper=nullptr, ValueMaterializer *Materializer=nullptr)
Clone OldFunc into NewFunc, transforming the old arguments into references to VMap values...
const DataLayout & getDataLayout() const
Get the data layout for the module&#39;s target platform.
Definition: Module.cpp:361
static ManagedStatic< DebugCounter > DC
Attribute unwrap(LLVMAttributeRef Attr)
Definition: Attributes.h:195
void copyAttributesFrom(const GlobalValue *Src)
Definition: GlobalAlias.h:62
void setInitializer(Constant *InitVal)
setInitializer - Sets the initializer for this global variable, removing any existing initializer if ...
Definition: Globals.cpp:340
LLVMContext & getContext() const
Get the global data context.
Definition: Module.h:237
unsigned getNumOperands() const
Definition: Metadata.cpp:1069
void setName(const Twine &Name)
Change the name of the value.
Definition: Value.cpp:295
global_iterator global_begin()
Definition: Module.h:555
Instruct the remapper to move distinct metadata instead of duplicating it when there are module-level...
Definition: ValueMapper.h:95
void setComdat(Comdat *C)
Definition: GlobalObject.h:103
StringRef getName() const
Definition: Comdat.cpp:24
static GCRegistry::Add< CoreCLRGC > E("coreclr", "CoreCLR-compatible GC")
This is an important base class in LLVM.
Definition: Constant.h:42
void copyAttributesFrom(const Function *Src)
copyAttributesFrom - copy all additional attributes (those not needed to create a Function) from the ...
Definition: Function.cpp:463
LLVMModuleRef LLVMCloneModule(LLVMModuleRef M)
Return an exact copy of the specified module.
arg_iterator arg_begin()
Definition: Function.h:649
static void copyComdat(GlobalObject *Dst, const GlobalObject *Src)
Definition: CloneModule.cpp:22
std::unique_ptr< Module > CloneModule(const Module *M)
Return an exact copy of the specified module.
Definition: CloneModule.cpp:35
Comdat * getOrInsertComdat(StringRef Name)
Return the Comdat in the module with the specified name.
Definition: Module.cpp:467
const std::string & getModuleIdentifier() const
Get the module identifier which is, essentially, the name of the module.
Definition: Module.h:208
Value * MapValue(const Value *V, ValueToValueMapTy &VM, RemapFlags Flags=RF_None, ValueMapTypeRemapper *TypeMapper=nullptr, ValueMaterializer *Materializer=nullptr)
Look up or compute a value in the value map.
Definition: ValueMapper.h:206
global_iterator global_end()
Definition: Module.h:557
Iterator for intrusive lists based on ilist_node.
void setSelectionKind(SelectionKind Val)
Definition: Comdat.h:43
This is a &#39;vector&#39; (really, a variable-sized array), optimized for the case when the array is small...
Definition: SmallVector.h:862
Module.h This file contains the declarations for the Module class.
void addMetadata(unsigned KindID, MDNode &MD)
Add a metadata attachment.
Definition: Metadata.cpp:1382
CHAIN = SC CHAIN, Imm128 - System call.
void setLinkage(LinkageTypes LT)
Definition: GlobalValue.h:439
StringRef getName() const
Definition: Metadata.cpp:1090
const Comdat * getComdat() const
Definition: GlobalObject.h:101
LLVMAttributeRef wrap(Attribute Attr)
Definition: Attributes.h:190
void copyAttributesFrom(const GlobalVariable *Src)
copyAttributesFrom - copy all additional attributes (those not needed to create a GlobalVariable) fro...
Definition: Globals.cpp:363
#define I(x, y, z)
Definition: MD5.cpp:58
const std::string & getModuleInlineAsm() const
Get any module-scope inline assembly blocks.
Definition: Module.h:241
Module * getParent()
Get the module that this global value is contained inside of...
Definition: GlobalValue.h:561
static Function * Create(FunctionType *Ty, LinkageTypes Linkage, const Twine &N="", Module *M=nullptr)
Definition: Function.h:136
void setPersonalityFn(Constant *Fn)
Definition: Function.cpp:1265
static GlobalAlias * create(Type *Ty, unsigned AddressSpace, LinkageTypes Linkage, const Twine &Name, Constant *Aliasee, Module *Parent)
If a parent module is specified, the alias is automatically inserted into the end of the specified mo...
Definition: Globals.cpp:400
void setAliasee(Constant *Aliasee)
These methods retrieve and set alias target.
Definition: Globals.cpp:437
SelectionKind getSelectionKind() const
Definition: Comdat.h:42