LLVM  12.0.0git
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());
26  DC->setSelectionKind(SC->getSelectionKind());
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  //
61  for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
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  GlobalVariable *GV = cast<GlobalVariable>(VMap[&*I]);
121 
123  I->getAllMetadata(MDs);
124  for (auto MD : MDs)
125  GV->addMetadata(MD.first,
126  *MapMetadata(MD.second, VMap, RF_MoveDistinctMDs));
127 
128  if (I->isDeclaration())
129  continue;
130 
131  if (!ShouldCloneDefinition(&*I)) {
132  // Skip after setting the correct linkage for an external reference.
134  continue;
135  }
136  if (I->hasInitializer())
137  GV->setInitializer(MapValue(I->getInitializer(), VMap));
138 
139  copyComdat(GV, &*I);
140  }
141 
142  // Similarly, copy over function bodies now...
143  //
144  for (const Function &I : M) {
145  if (I.isDeclaration())
146  continue;
147 
148  Function *F = cast<Function>(VMap[&I]);
149  if (!ShouldCloneDefinition(&I)) {
150  // Skip after setting the correct linkage for an external reference.
151  F->setLinkage(GlobalValue::ExternalLinkage);
152  // Personality function is not valid on a declaration.
153  F->setPersonalityFn(nullptr);
154  continue;
155  }
156 
157  Function::arg_iterator DestI = F->arg_begin();
158  for (Function::const_arg_iterator J = I.arg_begin(); J != I.arg_end();
159  ++J) {
160  DestI->setName(J->getName());
161  VMap[&*J] = &*DestI++;
162  }
163 
164  SmallVector<ReturnInst *, 8> Returns; // Ignore returns cloned.
165  CloneFunctionInto(F, &I, VMap, /*ModuleLevelChanges=*/true, Returns);
166 
167  if (I.hasPersonalityFn())
168  F->setPersonalityFn(MapValue(I.getPersonalityFn(), VMap));
169 
170  copyComdat(F, &I);
171  }
172 
173  // And aliases
174  for (Module::const_alias_iterator I = M.alias_begin(), E = M.alias_end();
175  I != E; ++I) {
176  // We already dealt with undefined aliases above.
177  if (!ShouldCloneDefinition(&*I))
178  continue;
179  GlobalAlias *GA = cast<GlobalAlias>(VMap[&*I]);
180  if (const Constant *C = I->getAliasee())
181  GA->setAliasee(MapValue(C, VMap));
182  }
183 
184  // And named metadata....
185  const auto* LLVM_DBG_CU = M.getNamedMetadata("llvm.dbg.cu");
186  for (Module::const_named_metadata_iterator I = M.named_metadata_begin(),
187  E = M.named_metadata_end();
188  I != E; ++I) {
189  const NamedMDNode &NMD = *I;
190  NamedMDNode *NewNMD = New->getOrInsertNamedMetadata(NMD.getName());
191  if (&NMD == LLVM_DBG_CU) {
192  // Do not insert duplicate operands.
194  for (const auto* Operand : NewNMD->operands())
195  Visited.insert(Operand);
196  for (const auto* Operand : NMD.operands()) {
197  auto* MappedOperand = MapMetadata(Operand, VMap);
198  if (Visited.insert(MappedOperand).second)
199  NewNMD->addOperand(MappedOperand);
200  }
201  } else
202  for (unsigned i = 0, e = NMD.getNumOperands(); i != e; ++i)
203  NewNMD->addOperand(MapMetadata(NMD.getOperand(i), VMap));
204  }
205 
206  return New;
207 }
208 
209 extern "C" {
210 
212  return wrap(CloneModule(*unwrap(M)).release());
213 }
214 
215 }
uint64_t CallInst * C
This class represents an incoming formal argument to a Function.
Definition: Argument.h:29
MDNode * getOperand(unsigned i) const
Definition: Metadata.cpp:1105
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:61
A Module instance is used to store all the information related to an LLVM module.
Definition: Module.h:67
void addOperand(MDNode *M)
Definition: Metadata.cpp:1111
An efficient, type-erasing, non-owning reference to a callable.
Definition: STLExtras.h:176
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:1350
static ManagedStatic< DebugCounter > DC
Attribute unwrap(LLVMAttributeRef Attr)
Definition: Attributes.h:229
void setInitializer(Constant *InitVal)
setInitializer - Sets the initializer for this global variable, removing any existing initializer if ...
Definition: Globals.cpp:389
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.
unsigned getNumOperands() const
Definition: Metadata.cpp:1101
void setName(const Twine &Name)
Change the name of the value.
Definition: Value.cpp:367
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:127
iterator_range< op_iterator > operands()
Definition: Metadata.h:1442
std::unique_ptr< Module > CloneModule(const Module &M)
Return an exact copy of the specified module.
Definition: CloneModule.cpp:34
static Function * Create(FunctionType *Ty, LinkageTypes Linkage, unsigned AddrSpace, const Twine &N="", Module *M=nullptr)
Definition: Function.h:137
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:621
LLVMModuleRef LLVMCloneModule(LLVMModuleRef M)
Return an exact copy of the specified module.
void addMetadata(unsigned KindID, MDNode &MD)
Add a metadata attachment.
Definition: Metadata.cpp:1249
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:364
constexpr double e
Definition: MathExtras.h:58
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:526
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
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:442
void copyAttributesFrom(const GlobalValue *Src)
This is a 'vector' (really, a variable-sized array), optimized for the case when the array is small.
Definition: SmallVector.h:1116
Module.h This file contains the declarations for the Module class.
CHAIN = SC CHAIN, Imm128 - System call.
void setLinkage(LinkageTypes LT)
Definition: GlobalValue.h:454
StringRef getName() const
Definition: Metadata.cpp:1122
const Comdat * getComdat() const
Definition: GlobalObject.h:125
LLVMAttributeRef wrap(Attribute Attr)
Definition: Attributes.h:224
void copyAttributesFrom(const GlobalVariable *Src)
copyAttributesFrom - copy all additional attributes (those not needed to create a GlobalVariable) fro...
Definition: Globals.cpp:412
#define I(x, y, z)
Definition: MD5.cpp:59
Module * getParent()
Get the module that this global value is contained inside of...
Definition: GlobalValue.h:572
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