LLVM  10.0.0svn
CloneModule.cpp
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1 //===- CloneModule.cpp - Clone an entire module ---------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file implements the CloneModule interface which makes a copy of an
10 // entire module.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "llvm/IR/Constant.h"
15 #include "llvm/IR/DerivedTypes.h"
16 #include "llvm/IR/Module.h"
19 using namespace llvm;
20 
21 static void copyComdat(GlobalObject *Dst, const GlobalObject *Src) {
22  const Comdat *SC = Src->getComdat();
23  if (!SC)
24  return;
25  Comdat *DC = Dst->getParent()->getOrInsertComdat(SC->getName());
27  Dst->setComdat(DC);
28 }
29 
30 /// This is not as easy as it might seem because we have to worry about making
31 /// copies of global variables and functions, and making their (initializers and
32 /// references, respectively) refer to the right globals.
33 ///
34 std::unique_ptr<Module> llvm::CloneModule(const Module &M) {
35  // Create the value map that maps things from the old module over to the new
36  // module.
37  ValueToValueMapTy VMap;
38  return CloneModule(M, VMap);
39 }
40 
41 std::unique_ptr<Module> llvm::CloneModule(const Module &M,
42  ValueToValueMapTy &VMap) {
43  return CloneModule(M, VMap, [](const GlobalValue *GV) { return true; });
44 }
45 
46 std::unique_ptr<Module> llvm::CloneModule(
47  const Module &M, ValueToValueMapTy &VMap,
48  function_ref<bool(const GlobalValue *)> ShouldCloneDefinition) {
49  // First off, we need to create the new module.
50  std::unique_ptr<Module> New =
51  std::make_unique<Module>(M.getModuleIdentifier(), M.getContext());
52  New->setSourceFileName(M.getSourceFileName());
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 =
77  Function::Create(cast<FunctionType>(I.getValueType()), I.getLinkage(),
78  I.getAddressSpace(), I.getName(), New.get());
79  NF->copyAttributesFrom(&I);
80  VMap[&I] = NF;
81  }
82 
83  // Loop over the aliases in the module
84  for (Module::const_alias_iterator I = M.alias_begin(), E = M.alias_end();
85  I != E; ++I) {
86  if (!ShouldCloneDefinition(&*I)) {
87  // An alias cannot act as an external reference, so we need to create
88  // either a function or a global variable depending on the value type.
89  // FIXME: Once pointee types are gone we can probably pick one or the
90  // other.
91  GlobalValue *GV;
92  if (I->getValueType()->isFunctionTy())
93  GV = Function::Create(cast<FunctionType>(I->getValueType()),
95  I->getAddressSpace(), I->getName(), New.get());
96  else
97  GV = new GlobalVariable(
98  *New, I->getValueType(), false, GlobalValue::ExternalLinkage,
99  nullptr, I->getName(), nullptr,
100  I->getThreadLocalMode(), I->getType()->getAddressSpace());
101  VMap[&*I] = GV;
102  // We do not copy attributes (mainly because copying between different
103  // kinds of globals is forbidden), but this is generally not required for
104  // correctness.
105  continue;
106  }
107  auto *GA = GlobalAlias::create(I->getValueType(),
108  I->getType()->getPointerAddressSpace(),
109  I->getLinkage(), I->getName(), New.get());
110  GA->copyAttributesFrom(&*I);
111  VMap[&*I] = GA;
112  }
113 
114  // Now that all of the things that global variable initializer can refer to
115  // have been created, loop through and copy the global variable referrers
116  // over... We also set the attributes on the global now.
117  //
118  for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
119  I != E; ++I) {
120  if (I->isDeclaration())
121  continue;
122 
123  GlobalVariable *GV = cast<GlobalVariable>(VMap[&*I]);
124  if (!ShouldCloneDefinition(&*I)) {
125  // Skip after setting the correct linkage for an external reference.
127  continue;
128  }
129  if (I->hasInitializer())
130  GV->setInitializer(MapValue(I->getInitializer(), VMap));
131 
133  I->getAllMetadata(MDs);
134  for (auto MD : MDs)
135  GV->addMetadata(MD.first,
136  *MapMetadata(MD.second, VMap, RF_MoveDistinctMDs));
137 
138  copyComdat(GV, &*I);
139  }
140 
141  // Similarly, copy over function bodies now...
142  //
143  for (const Function &I : M) {
144  if (I.isDeclaration())
145  continue;
146 
147  Function *F = cast<Function>(VMap[&I]);
148  if (!ShouldCloneDefinition(&I)) {
149  // Skip after setting the correct linkage for an external reference.
151  // Personality function is not valid on a declaration.
152  F->setPersonalityFn(nullptr);
153  continue;
154  }
155 
156  Function::arg_iterator DestI = F->arg_begin();
157  for (Function::const_arg_iterator J = I.arg_begin(); J != I.arg_end();
158  ++J) {
159  DestI->setName(J->getName());
160  VMap[&*J] = &*DestI++;
161  }
162 
163  SmallVector<ReturnInst *, 8> Returns; // Ignore returns cloned.
164  CloneFunctionInto(F, &I, VMap, /*ModuleLevelChanges=*/true, Returns);
165 
166  if (I.hasPersonalityFn())
167  F->setPersonalityFn(MapValue(I.getPersonalityFn(), VMap));
168 
169  copyComdat(F, &I);
170  }
171 
172  // And aliases
173  for (Module::const_alias_iterator I = M.alias_begin(), E = M.alias_end();
174  I != E; ++I) {
175  // We already dealt with undefined aliases above.
176  if (!ShouldCloneDefinition(&*I))
177  continue;
178  GlobalAlias *GA = cast<GlobalAlias>(VMap[&*I]);
179  if (const Constant *C = I->getAliasee())
180  GA->setAliasee(MapValue(C, VMap));
181  }
182 
183  // And named metadata....
184  const auto* LLVM_DBG_CU = M.getNamedMetadata("llvm.dbg.cu");
185  for (Module::const_named_metadata_iterator I = M.named_metadata_begin(),
186  E = M.named_metadata_end();
187  I != E; ++I) {
188  const NamedMDNode &NMD = *I;
189  NamedMDNode *NewNMD = New->getOrInsertNamedMetadata(NMD.getName());
190  if (&NMD == LLVM_DBG_CU) {
191  // Do not insert duplicate operands.
193  for (const auto* Operand : NewNMD->operands())
194  Visited.insert(Operand);
195  for (const auto* Operand : NMD.operands()) {
196  auto* MappedOperand = MapMetadata(Operand, VMap);
197  if (Visited.insert(MappedOperand).second)
198  NewNMD->addOperand(MappedOperand);
199  }
200  } else
201  for (unsigned i = 0, e = NMD.getNumOperands(); i != e; ++i)
202  NewNMD->addOperand(MapMetadata(NMD.getOperand(i), VMap));
203  }
204 
205  return New;
206 }
207 
208 extern "C" {
209 
211  return wrap(CloneModule(*unwrap(M)).release());
212 }
213 
214 }
uint64_t CallInst * C
const std::string & getTargetTriple() const
Get the target triple which is a string describing the target host.
Definition: Module.h:240
This class represents an incoming formal argument to a Function.
Definition: Argument.h:29
MDNode * getOperand(unsigned i) const
Definition: Metadata.cpp:1080
This class represents lattice values for constants.
Definition: AllocatorList.h:23
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:65
void addOperand(MDNode *M)
Definition: Metadata.cpp:1086
An efficient, type-erasing, non-owning reference to a callable.
Definition: STLExtras.h:104
Externally visible function.
Definition: GlobalValue.h:48
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:1325
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:369
static ManagedStatic< DebugCounter > DC
Attribute unwrap(LLVMAttributeRef Attr)
Definition: Attributes.h:204
void setInitializer(Constant *InitVal)
setInitializer - Sets the initializer for this global variable, removing any existing initializer if ...
Definition: Globals.cpp:388
LLVMContext & getContext() const
Get the global data context.
Definition: Module.h:244
unsigned getNumOperands() const
Definition: Metadata.cpp:1076
void setName(const Twine &Name)
Change the name of the value.
Definition: Value.cpp:285
global_iterator global_begin()
Definition: Module.h:581
Instruct the remapper to move distinct metadata instead of duplicating it when there are module-level...
Definition: ValueMapper.h:94
void setComdat(Comdat *C)
Definition: GlobalObject.h:108
iterator_range< op_iterator > operands()
Definition: Metadata.h:1417
const std::string & getSourceFileName() const
Get the module&#39;s original source file name.
Definition: Module.h:221
std::unique_ptr< Module > CloneModule(const Module &M)
Return an exact copy of the specified module.
Definition: CloneModule.cpp:34
StringRef getName() const
Definition: Comdat.cpp:26
static Function * Create(FunctionType *Ty, LinkageTypes Linkage, unsigned AddrSpace, const Twine &N="", Module *M=nullptr)
Definition: Function.h:135
static GCRegistry::Add< CoreCLRGC > E("coreclr", "CoreCLR-compatible GC")
This is an important base class in LLVM.
Definition: Constant.h:41
void copyAttributesFrom(const Function *Src)
copyAttributesFrom - copy all additional attributes (those not needed to create a Function) from the ...
Definition: Function.cpp:497
LLVMModuleRef LLVMCloneModule(LLVMModuleRef M)
Return an exact copy of the specified module.
std::pair< iterator, bool > insert(PtrType Ptr)
Inserts Ptr if and only if there is no element in the container equal to Ptr.
Definition: SmallPtrSet.h:370
constexpr double e
Definition: MathExtras.h:57
arg_iterator arg_begin()
Definition: Function.h:695
static void copyComdat(GlobalObject *Dst, const GlobalObject *Src)
Definition: CloneModule.cpp:21
Comdat * getOrInsertComdat(StringRef Name)
Return the Comdat in the module with the specified name.
Definition: Module.cpp:482
const std::string & getModuleIdentifier() const
Get the module identifier which is, essentially, the name of the module.
Definition: Module.h:210
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:583
Iterator for intrusive lists based on ilist_node.
SmallPtrSet - This class implements a set which is optimized for holding SmallSize or less elements...
Definition: SmallPtrSet.h:417
void setSelectionKind(SelectionKind Val)
Definition: Comdat.h:45
void copyAttributesFrom(const GlobalValue *Src)
This is a &#39;vector&#39; (really, a variable-sized array), optimized for the case when the array is small...
Definition: SmallVector.h:837
Module.h This file contains the declarations for the Module class.
void addMetadata(unsigned KindID, MDNode &MD)
Add a metadata attachment.
Definition: Metadata.cpp:1390
CHAIN = SC CHAIN, Imm128 - System call.
void setLinkage(LinkageTypes LT)
Definition: GlobalValue.h:454
StringRef getName() const
Definition: Metadata.cpp:1097
const Comdat * getComdat() const
Definition: GlobalObject.h:106
LLVMAttributeRef wrap(Attribute Attr)
Definition: Attributes.h:199
void copyAttributesFrom(const GlobalVariable *Src)
copyAttributesFrom - copy all additional attributes (those not needed to create a GlobalVariable) fro...
Definition: Globals.cpp:411
#define I(x, y, z)
Definition: MD5.cpp:58
const std::string & getModuleInlineAsm() const
Get any module-scope inline assembly blocks.
Definition: Module.h:248
Module * getParent()
Get the module that this global value is contained inside of...
Definition: GlobalValue.h:575
void setPersonalityFn(Constant *Fn)
Definition: Function.cpp:1470
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:485
void setAliasee(Constant *Aliasee)
These methods retrieve and set alias target.
Definition: Globals.cpp:522
SelectionKind getSelectionKind() const
Definition: Comdat.h:44