1 //===- lib/Linker/LinkModules.cpp - Module Linker Implementation ----------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements the LLVM module linker.
12 //===----------------------------------------------------------------------===//
14 #include "llvm/Linker.h"
15 #include "llvm/Constants.h"
16 #include "llvm/DerivedTypes.h"
17 #include "llvm/Instructions.h"
18 #include "llvm/Module.h"
19 #include "llvm/ADT/SmallPtrSet.h"
20 #include "llvm/Support/raw_ostream.h"
21 #include "llvm/Support/Path.h"
22 #include "llvm/Transforms/Utils/Cloning.h"
23 #include "llvm/Transforms/Utils/ValueMapper.h"
26 //===----------------------------------------------------------------------===//
27 // TypeMap implementation.
28 //===----------------------------------------------------------------------===//
31 class TypeMapTy : public ValueMapTypeRemapper {
32 /// MappedTypes - This is a mapping from a source type to a destination type
34 DenseMap<Type*, Type*> MappedTypes;
36 /// SpeculativeTypes - When checking to see if two subgraphs are isomorphic,
37 /// we speculatively add types to MappedTypes, but keep track of them here in
38 /// case we need to roll back.
39 SmallVector<Type*, 16> SpeculativeTypes;
41 /// SrcDefinitionsToResolve - This is a list of non-opaque structs in the
42 /// source module that are mapped to an opaque struct in the destination
44 SmallVector<StructType*, 16> SrcDefinitionsToResolve;
46 /// DstResolvedOpaqueTypes - This is the set of opaque types in the
47 /// destination modules who are getting a body from the source module.
48 SmallPtrSet<StructType*, 16> DstResolvedOpaqueTypes;
51 /// addTypeMapping - Indicate that the specified type in the destination
52 /// module is conceptually equivalent to the specified type in the source
54 void addTypeMapping(Type *DstTy, Type *SrcTy);
56 /// linkDefinedTypeBodies - Produce a body for an opaque type in the dest
57 /// module from a type definition in the source module.
58 void linkDefinedTypeBodies();
60 /// get - Return the mapped type to use for the specified input type from the
62 Type *get(Type *SrcTy);
64 FunctionType *get(FunctionType *T) {return cast<FunctionType>(get((Type*)T));}
67 Type *getImpl(Type *T);
68 /// remapType - Implement the ValueMapTypeRemapper interface.
69 Type *remapType(Type *SrcTy) {
73 bool areTypesIsomorphic(Type *DstTy, Type *SrcTy);
77 void TypeMapTy::addTypeMapping(Type *DstTy, Type *SrcTy) {
78 Type *&Entry = MappedTypes[SrcTy];
86 // Check to see if these types are recursively isomorphic and establish a
87 // mapping between them if so.
88 if (!areTypesIsomorphic(DstTy, SrcTy)) {
89 // Oops, they aren't isomorphic. Just discard this request by rolling out
90 // any speculative mappings we've established.
91 for (unsigned i = 0, e = SpeculativeTypes.size(); i != e; ++i)
92 MappedTypes.erase(SpeculativeTypes[i]);
94 SpeculativeTypes.clear();
97 /// areTypesIsomorphic - Recursively walk this pair of types, returning true
98 /// if they are isomorphic, false if they are not.
99 bool TypeMapTy::areTypesIsomorphic(Type *DstTy, Type *SrcTy) {
100 // Two types with differing kinds are clearly not isomorphic.
101 if (DstTy->getTypeID() != SrcTy->getTypeID()) return false;
103 // If we have an entry in the MappedTypes table, then we have our answer.
104 Type *&Entry = MappedTypes[SrcTy];
106 return Entry == DstTy;
108 // Two identical types are clearly isomorphic. Remember this
109 // non-speculatively.
110 if (DstTy == SrcTy) {
115 // Okay, we have two types with identical kinds that we haven't seen before.
117 // If this is an opaque struct type, special case it.
118 if (StructType *SSTy = dyn_cast<StructType>(SrcTy)) {
119 // Mapping an opaque type to any struct, just keep the dest struct.
120 if (SSTy->isOpaque()) {
122 SpeculativeTypes.push_back(SrcTy);
126 // Mapping a non-opaque source type to an opaque dest. If this is the first
127 // type that we're mapping onto this destination type then we succeed. Keep
128 // the dest, but fill it in later. This doesn't need to be speculative. If
129 // this is the second (different) type that we're trying to map onto the
130 // same opaque type then we fail.
131 if (cast<StructType>(DstTy)->isOpaque()) {
132 // We can only map one source type onto the opaque destination type.
133 if (!DstResolvedOpaqueTypes.insert(cast<StructType>(DstTy)))
135 SrcDefinitionsToResolve.push_back(SSTy);
141 // If the number of subtypes disagree between the two types, then we fail.
142 if (SrcTy->getNumContainedTypes() != DstTy->getNumContainedTypes())
145 // Fail if any of the extra properties (e.g. array size) of the type disagree.
146 if (isa<IntegerType>(DstTy))
147 return false; // bitwidth disagrees.
148 if (PointerType *PT = dyn_cast<PointerType>(DstTy)) {
149 if (PT->getAddressSpace() != cast<PointerType>(SrcTy)->getAddressSpace())
152 } else if (FunctionType *FT = dyn_cast<FunctionType>(DstTy)) {
153 if (FT->isVarArg() != cast<FunctionType>(SrcTy)->isVarArg())
155 } else if (StructType *DSTy = dyn_cast<StructType>(DstTy)) {
156 StructType *SSTy = cast<StructType>(SrcTy);
157 if (DSTy->isLiteral() != SSTy->isLiteral() ||
158 DSTy->isPacked() != SSTy->isPacked())
160 } else if (ArrayType *DATy = dyn_cast<ArrayType>(DstTy)) {
161 if (DATy->getNumElements() != cast<ArrayType>(SrcTy)->getNumElements())
163 } else if (VectorType *DVTy = dyn_cast<VectorType>(DstTy)) {
164 if (DVTy->getNumElements() != cast<ArrayType>(SrcTy)->getNumElements())
168 // Otherwise, we speculate that these two types will line up and recursively
169 // check the subelements.
171 SpeculativeTypes.push_back(SrcTy);
173 for (unsigned i = 0, e = SrcTy->getNumContainedTypes(); i != e; ++i)
174 if (!areTypesIsomorphic(DstTy->getContainedType(i),
175 SrcTy->getContainedType(i)))
178 // If everything seems to have lined up, then everything is great.
182 /// linkDefinedTypeBodies - Produce a body for an opaque type in the dest
183 /// module from a type definition in the source module.
184 void TypeMapTy::linkDefinedTypeBodies() {
185 SmallVector<Type*, 16> Elements;
186 SmallString<16> TmpName;
188 // Note that processing entries in this loop (calling 'get') can add new
189 // entries to the SrcDefinitionsToResolve vector.
190 while (!SrcDefinitionsToResolve.empty()) {
191 StructType *SrcSTy = SrcDefinitionsToResolve.pop_back_val();
192 StructType *DstSTy = cast<StructType>(MappedTypes[SrcSTy]);
194 // TypeMap is a many-to-one mapping, if there were multiple types that
195 // provide a body for DstSTy then previous iterations of this loop may have
196 // already handled it. Just ignore this case.
197 if (!DstSTy->isOpaque()) continue;
198 assert(!SrcSTy->isOpaque() && "Not resolving a definition?");
200 // Map the body of the source type over to a new body for the dest type.
201 Elements.resize(SrcSTy->getNumElements());
202 for (unsigned i = 0, e = Elements.size(); i != e; ++i)
203 Elements[i] = getImpl(SrcSTy->getElementType(i));
205 DstSTy->setBody(Elements, SrcSTy->isPacked());
207 // If DstSTy has no name or has a longer name than STy, then viciously steal
209 if (!SrcSTy->hasName()) continue;
210 StringRef SrcName = SrcSTy->getName();
212 if (!DstSTy->hasName() || DstSTy->getName().size() > SrcName.size()) {
213 TmpName.insert(TmpName.end(), SrcName.begin(), SrcName.end());
215 DstSTy->setName(TmpName.str());
220 DstResolvedOpaqueTypes.clear();
224 /// get - Return the mapped type to use for the specified input type from the
226 Type *TypeMapTy::get(Type *Ty) {
227 Type *Result = getImpl(Ty);
229 // If this caused a reference to any struct type, resolve it before returning.
230 if (!SrcDefinitionsToResolve.empty())
231 linkDefinedTypeBodies();
235 /// getImpl - This is the recursive version of get().
236 Type *TypeMapTy::getImpl(Type *Ty) {
237 // If we already have an entry for this type, return it.
238 Type **Entry = &MappedTypes[Ty];
239 if (*Entry) return *Entry;
241 // If this is not a named struct type, then just map all of the elements and
242 // then rebuild the type from inside out.
243 if (!isa<StructType>(Ty) || cast<StructType>(Ty)->isLiteral()) {
244 // If there are no element types to map, then the type is itself. This is
245 // true for the anonymous {} struct, things like 'float', integers, etc.
246 if (Ty->getNumContainedTypes() == 0)
249 // Remap all of the elements, keeping track of whether any of them change.
250 bool AnyChange = false;
251 SmallVector<Type*, 4> ElementTypes;
252 ElementTypes.resize(Ty->getNumContainedTypes());
253 for (unsigned i = 0, e = Ty->getNumContainedTypes(); i != e; ++i) {
254 ElementTypes[i] = getImpl(Ty->getContainedType(i));
255 AnyChange |= ElementTypes[i] != Ty->getContainedType(i);
258 // If we found our type while recursively processing stuff, just use it.
259 Entry = &MappedTypes[Ty];
260 if (*Entry) return *Entry;
262 // If all of the element types mapped directly over, then the type is usable
267 // Otherwise, rebuild a modified type.
268 switch (Ty->getTypeID()) {
269 default: assert(0 && "unknown derived type to remap");
270 case Type::ArrayTyID:
271 return *Entry = ArrayType::get(ElementTypes[0],
272 cast<ArrayType>(Ty)->getNumElements());
273 case Type::VectorTyID:
274 return *Entry = VectorType::get(ElementTypes[0],
275 cast<VectorType>(Ty)->getNumElements());
276 case Type::PointerTyID:
277 return *Entry = PointerType::get(ElementTypes[0],
278 cast<PointerType>(Ty)->getAddressSpace());
279 case Type::FunctionTyID:
280 return *Entry = FunctionType::get(ElementTypes[0],
281 makeArrayRef(ElementTypes).slice(1),
282 cast<FunctionType>(Ty)->isVarArg());
283 case Type::StructTyID:
284 // Note that this is only reached for anonymous structs.
285 return *Entry = StructType::get(Ty->getContext(), ElementTypes,
286 cast<StructType>(Ty)->isPacked());
290 // Otherwise, this is an unmapped named struct. If the struct can be directly
291 // mapped over, just use it as-is. This happens in a case when the linked-in
292 // module has something like:
293 // %T = type {%T*, i32}
294 // @GV = global %T* null
295 // where T does not exist at all in the destination module.
297 // The other case we watch for is when the type is not in the destination
298 // module, but that it has to be rebuilt because it refers to something that
299 // is already mapped. For example, if the destination module has:
301 // and the source module has something like
302 // %A' = type { i32 }
303 // %B = type { %A'* }
304 // @GV = global %B* null
305 // then we want to create a new type: "%B = type { %A*}" and have it take the
306 // pristine "%B" name from the source module.
308 // To determine which case this is, we have to recursively walk the type graph
309 // speculating that we'll be able to reuse it unmodified. Only if this is
310 // safe would we map the entire thing over. Because this is an optimization,
311 // and is not required for the prettiness of the linked module, we just skip
312 // it and always rebuild a type here.
313 StructType *STy = cast<StructType>(Ty);
315 // If the type is opaque, we can just use it directly.
319 // Otherwise we create a new type and resolve its body later. This will be
320 // resolved by the top level of get().
321 SrcDefinitionsToResolve.push_back(STy);
322 StructType *DTy = StructType::create(STy->getContext());
323 DstResolvedOpaqueTypes.insert(DTy);
329 //===----------------------------------------------------------------------===//
330 // ModuleLinker implementation.
331 //===----------------------------------------------------------------------===//
334 /// ModuleLinker - This is an implementation class for the LinkModules
335 /// function, which is the entrypoint for this file.
341 /// ValueMap - Mapping of values from what they used to be in Src, to what
342 /// they are now in DstM. ValueToValueMapTy is a ValueMap, which involves
343 /// some overhead due to the use of Value handles which the Linker doesn't
344 /// actually need, but this allows us to reuse the ValueMapper code.
345 ValueToValueMapTy ValueMap;
347 struct AppendingVarInfo {
348 GlobalVariable *NewGV; // New aggregate global in dest module.
349 Constant *DstInit; // Old initializer from dest module.
350 Constant *SrcInit; // Old initializer from src module.
353 std::vector<AppendingVarInfo> AppendingVars;
355 unsigned Mode; // Mode to treat source module.
357 // Set of items not to link in from source.
358 SmallPtrSet<const Value*, 16> DoNotLinkFromSource;
360 // Vector of functions to lazily link in.
361 std::vector<Function*> LazilyLinkFunctions;
364 std::string ErrorMsg;
366 ModuleLinker(Module *dstM, Module *srcM, unsigned mode)
367 : DstM(dstM), SrcM(srcM), Mode(mode) { }
372 /// emitError - Helper method for setting a message and returning an error
374 bool emitError(const Twine &Message) {
375 ErrorMsg = Message.str();
379 /// getLinkageResult - This analyzes the two global values and determines
380 /// what the result will look like in the destination module.
381 bool getLinkageResult(GlobalValue *Dest, const GlobalValue *Src,
382 GlobalValue::LinkageTypes <, bool &LinkFromSrc);
384 /// getLinkedToGlobal - Given a global in the source module, return the
385 /// global in the destination module that is being linked to, if any.
386 GlobalValue *getLinkedToGlobal(GlobalValue *SrcGV) {
387 // If the source has no name it can't link. If it has local linkage,
388 // there is no name match-up going on.
389 if (!SrcGV->hasName() || SrcGV->hasLocalLinkage())
392 // Otherwise see if we have a match in the destination module's symtab.
393 GlobalValue *DGV = DstM->getNamedValue(SrcGV->getName());
394 if (DGV == 0) return 0;
396 // If we found a global with the same name in the dest module, but it has
397 // internal linkage, we are really not doing any linkage here.
398 if (DGV->hasLocalLinkage())
401 // Otherwise, we do in fact link to the destination global.
405 void computeTypeMapping();
407 bool linkAppendingVarProto(GlobalVariable *DstGV, GlobalVariable *SrcGV);
408 bool linkGlobalProto(GlobalVariable *SrcGV);
409 bool linkFunctionProto(Function *SrcF);
410 bool linkAliasProto(GlobalAlias *SrcA);
412 void linkAppendingVarInit(const AppendingVarInfo &AVI);
413 void linkGlobalInits();
414 void linkFunctionBody(Function *Dst, Function *Src);
415 void linkAliasBodies();
416 void linkNamedMDNodes();
422 /// forceRenaming - The LLVM SymbolTable class autorenames globals that conflict
423 /// in the symbol table. This is good for all clients except for us. Go
424 /// through the trouble to force this back.
425 static void forceRenaming(GlobalValue *GV, StringRef Name) {
426 // If the global doesn't force its name or if it already has the right name,
427 // there is nothing for us to do.
428 if (GV->hasLocalLinkage() || GV->getName() == Name)
431 Module *M = GV->getParent();
433 // If there is a conflict, rename the conflict.
434 if (GlobalValue *ConflictGV = M->getNamedValue(Name)) {
435 GV->takeName(ConflictGV);
436 ConflictGV->setName(Name); // This will cause ConflictGV to get renamed
437 assert(ConflictGV->getName() != Name && "forceRenaming didn't work");
439 GV->setName(Name); // Force the name back
443 /// CopyGVAttributes - copy additional attributes (those not needed to construct
444 /// a GlobalValue) from the SrcGV to the DestGV.
445 static void CopyGVAttributes(GlobalValue *DestGV, const GlobalValue *SrcGV) {
446 // Use the maximum alignment, rather than just copying the alignment of SrcGV.
447 unsigned Alignment = std::max(DestGV->getAlignment(), SrcGV->getAlignment());
448 DestGV->copyAttributesFrom(SrcGV);
449 DestGV->setAlignment(Alignment);
451 forceRenaming(DestGV, SrcGV->getName());
454 /// getLinkageResult - This analyzes the two global values and determines what
455 /// the result will look like in the destination module. In particular, it
456 /// computes the resultant linkage type, computes whether the global in the
457 /// source should be copied over to the destination (replacing the existing
458 /// one), and computes whether this linkage is an error or not. It also performs
459 /// visibility checks: we cannot link together two symbols with different
461 bool ModuleLinker::getLinkageResult(GlobalValue *Dest, const GlobalValue *Src,
462 GlobalValue::LinkageTypes <,
464 assert(Dest && "Must have two globals being queried");
465 assert(!Src->hasLocalLinkage() &&
466 "If Src has internal linkage, Dest shouldn't be set!");
468 bool SrcIsDeclaration = Src->isDeclaration() && !Src->isMaterializable();
469 bool DestIsDeclaration = Dest->isDeclaration();
471 if (SrcIsDeclaration) {
472 // If Src is external or if both Src & Dest are external.. Just link the
473 // external globals, we aren't adding anything.
474 if (Src->hasDLLImportLinkage()) {
475 // If one of GVs has DLLImport linkage, result should be dllimport'ed.
476 if (DestIsDeclaration) {
478 LT = Src->getLinkage();
480 } else if (Dest->hasExternalWeakLinkage()) {
481 // If the Dest is weak, use the source linkage.
483 LT = Src->getLinkage();
486 LT = Dest->getLinkage();
488 } else if (DestIsDeclaration && !Dest->hasDLLImportLinkage()) {
489 // If Dest is external but Src is not:
491 LT = Src->getLinkage();
492 } else if (Src->isWeakForLinker()) {
493 // At this point we know that Dest has LinkOnce, External*, Weak, Common,
495 if (Dest->hasExternalWeakLinkage() ||
496 Dest->hasAvailableExternallyLinkage() ||
497 (Dest->hasLinkOnceLinkage() &&
498 (Src->hasWeakLinkage() || Src->hasCommonLinkage()))) {
500 LT = Src->getLinkage();
503 LT = Dest->getLinkage();
505 } else if (Dest->isWeakForLinker()) {
506 // At this point we know that Src has External* or DLL* linkage.
507 if (Src->hasExternalWeakLinkage()) {
509 LT = Dest->getLinkage();
512 LT = GlobalValue::ExternalLinkage;
515 assert((Dest->hasExternalLinkage() || Dest->hasDLLImportLinkage() ||
516 Dest->hasDLLExportLinkage() || Dest->hasExternalWeakLinkage()) &&
517 (Src->hasExternalLinkage() || Src->hasDLLImportLinkage() ||
518 Src->hasDLLExportLinkage() || Src->hasExternalWeakLinkage()) &&
519 "Unexpected linkage type!");
520 return emitError("Linking globals named '" + Src->getName() +
521 "': symbol multiply defined!");
525 if (Src->getVisibility() != Dest->getVisibility() &&
526 !SrcIsDeclaration && !DestIsDeclaration &&
527 !Src->hasAvailableExternallyLinkage() &&
528 !Dest->hasAvailableExternallyLinkage())
529 return emitError("Linking globals named '" + Src->getName() +
530 "': symbols have different visibilities!");
534 /// computeTypeMapping - Loop over all of the linked values to compute type
535 /// mappings. For example, if we link "extern Foo *x" and "Foo *x = NULL", then
536 /// we have two struct types 'Foo' but one got renamed when the module was
537 /// loaded into the same LLVMContext.
538 void ModuleLinker::computeTypeMapping() {
539 // Incorporate globals.
540 for (Module::global_iterator I = SrcM->global_begin(),
541 E = SrcM->global_end(); I != E; ++I) {
542 GlobalValue *DGV = getLinkedToGlobal(I);
543 if (DGV == 0) continue;
545 if (!DGV->hasAppendingLinkage() || !I->hasAppendingLinkage()) {
546 TypeMap.addTypeMapping(DGV->getType(), I->getType());
550 // Unify the element type of appending arrays.
551 ArrayType *DAT = cast<ArrayType>(DGV->getType()->getElementType());
552 ArrayType *SAT = cast<ArrayType>(I->getType()->getElementType());
553 TypeMap.addTypeMapping(DAT->getElementType(), SAT->getElementType());
556 // Incorporate functions.
557 for (Module::iterator I = SrcM->begin(), E = SrcM->end(); I != E; ++I) {
558 if (GlobalValue *DGV = getLinkedToGlobal(I))
559 TypeMap.addTypeMapping(DGV->getType(), I->getType());
562 // Incorporate types by name, scanning all the types in the source module.
563 // At this point, the destination module may have a type "%foo = { i32 }" for
564 // example. When the source module got loaded into the same LLVMContext, if
565 // it had the same type, it would have been renamed to "%foo.42 = { i32 }".
566 // Though it isn't required for correctness, attempt to link these up to clean
568 std::vector<StructType*> SrcStructTypes;
569 SrcM->findUsedStructTypes(SrcStructTypes);
571 SmallPtrSet<StructType*, 32> SrcStructTypesSet(SrcStructTypes.begin(),
572 SrcStructTypes.end());
574 for (unsigned i = 0, e = SrcStructTypes.size(); i != e; ++i) {
575 StructType *ST = SrcStructTypes[i];
576 if (!ST->hasName()) continue;
578 // Check to see if there is a dot in the name followed by a digit.
579 size_t DotPos = ST->getName().rfind('.');
580 if (DotPos == 0 || DotPos == StringRef::npos ||
581 ST->getName().back() == '.' || !isdigit(ST->getName()[DotPos+1]))
584 // Check to see if the destination module has a struct with the prefix name.
585 if (StructType *DST = DstM->getTypeByName(ST->getName().substr(0, DotPos)))
586 // Don't use it if this actually came from the source module. They're in
587 // the same LLVMContext after all.
588 if (!SrcStructTypesSet.count(DST))
589 TypeMap.addTypeMapping(DST, ST);
593 // Don't bother incorporating aliases, they aren't generally typed well.
595 // Now that we have discovered all of the type equivalences, get a body for
596 // any 'opaque' types in the dest module that are now resolved.
597 TypeMap.linkDefinedTypeBodies();
600 /// linkAppendingVarProto - If there were any appending global variables, link
601 /// them together now. Return true on error.
602 bool ModuleLinker::linkAppendingVarProto(GlobalVariable *DstGV,
603 GlobalVariable *SrcGV) {
605 if (!SrcGV->hasAppendingLinkage() || !DstGV->hasAppendingLinkage())
606 return emitError("Linking globals named '" + SrcGV->getName() +
607 "': can only link appending global with another appending global!");
609 ArrayType *DstTy = cast<ArrayType>(DstGV->getType()->getElementType());
611 cast<ArrayType>(TypeMap.get(SrcGV->getType()->getElementType()));
612 Type *EltTy = DstTy->getElementType();
614 // Check to see that they two arrays agree on type.
615 if (EltTy != SrcTy->getElementType())
616 return emitError("Appending variables with different element types!");
617 if (DstGV->isConstant() != SrcGV->isConstant())
618 return emitError("Appending variables linked with different const'ness!");
620 if (DstGV->getAlignment() != SrcGV->getAlignment())
622 "Appending variables with different alignment need to be linked!");
624 if (DstGV->getVisibility() != SrcGV->getVisibility())
626 "Appending variables with different visibility need to be linked!");
628 if (DstGV->getSection() != SrcGV->getSection())
630 "Appending variables with different section name need to be linked!");
632 uint64_t NewSize = DstTy->getNumElements() + SrcTy->getNumElements();
633 ArrayType *NewType = ArrayType::get(EltTy, NewSize);
635 // Create the new global variable.
637 new GlobalVariable(*DstGV->getParent(), NewType, SrcGV->isConstant(),
638 DstGV->getLinkage(), /*init*/0, /*name*/"", DstGV,
639 DstGV->isThreadLocal(),
640 DstGV->getType()->getAddressSpace());
642 // Propagate alignment, visibility and section info.
643 CopyGVAttributes(NG, DstGV);
645 AppendingVarInfo AVI;
647 AVI.DstInit = DstGV->getInitializer();
648 AVI.SrcInit = SrcGV->getInitializer();
649 AppendingVars.push_back(AVI);
651 // Replace any uses of the two global variables with uses of the new
653 ValueMap[SrcGV] = ConstantExpr::getBitCast(NG, TypeMap.get(SrcGV->getType()));
655 DstGV->replaceAllUsesWith(ConstantExpr::getBitCast(NG, DstGV->getType()));
656 DstGV->eraseFromParent();
658 // Track the source variable so we don't try to link it.
659 DoNotLinkFromSource.insert(SrcGV);
664 /// linkGlobalProto - Loop through the global variables in the src module and
665 /// merge them into the dest module.
666 bool ModuleLinker::linkGlobalProto(GlobalVariable *SGV) {
667 GlobalValue *DGV = getLinkedToGlobal(SGV);
670 // Concatenation of appending linkage variables is magic and handled later.
671 if (DGV->hasAppendingLinkage() || SGV->hasAppendingLinkage())
672 return linkAppendingVarProto(cast<GlobalVariable>(DGV), SGV);
674 // Determine whether linkage of these two globals follows the source
675 // module's definition or the destination module's definition.
676 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage;
677 bool LinkFromSrc = false;
678 if (getLinkageResult(DGV, SGV, NewLinkage, LinkFromSrc))
681 // If we're not linking from the source, then keep the definition that we
684 // Special case for const propagation.
685 if (GlobalVariable *DGVar = dyn_cast<GlobalVariable>(DGV))
686 if (DGVar->isDeclaration() && SGV->isConstant() && !DGVar->isConstant())
687 DGVar->setConstant(true);
689 // Set calculated linkage.
690 DGV->setLinkage(NewLinkage);
692 // Make sure to remember this mapping.
693 ValueMap[SGV] = ConstantExpr::getBitCast(DGV,TypeMap.get(SGV->getType()));
695 // Track the source global so that we don't attempt to copy it over when
696 // processing global initializers.
697 DoNotLinkFromSource.insert(SGV);
703 // No linking to be performed or linking from the source: simply create an
704 // identical version of the symbol over in the dest module... the
705 // initializer will be filled in later by LinkGlobalInits.
706 GlobalVariable *NewDGV =
707 new GlobalVariable(*DstM, TypeMap.get(SGV->getType()->getElementType()),
708 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
709 SGV->getName(), /*insertbefore*/0,
710 SGV->isThreadLocal(),
711 SGV->getType()->getAddressSpace());
712 // Propagate alignment, visibility and section info.
713 CopyGVAttributes(NewDGV, SGV);
716 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDGV, DGV->getType()));
717 DGV->eraseFromParent();
720 // Make sure to remember this mapping.
721 ValueMap[SGV] = NewDGV;
725 /// linkFunctionProto - Link the function in the source module into the
726 /// destination module if needed, setting up mapping information.
727 bool ModuleLinker::linkFunctionProto(Function *SF) {
728 GlobalValue *DGV = getLinkedToGlobal(SF);
731 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage;
732 bool LinkFromSrc = false;
733 if (getLinkageResult(DGV, SF, NewLinkage, LinkFromSrc))
737 // Set calculated linkage
738 DGV->setLinkage(NewLinkage);
740 // Make sure to remember this mapping.
741 ValueMap[SF] = ConstantExpr::getBitCast(DGV, TypeMap.get(SF->getType()));
743 // Track the function from the source module so we don't attempt to remap
745 DoNotLinkFromSource.insert(SF);
751 // If there is no linkage to be performed or we are linking from the source,
753 Function *NewDF = Function::Create(TypeMap.get(SF->getFunctionType()),
754 SF->getLinkage(), SF->getName(), DstM);
755 CopyGVAttributes(NewDF, SF);
758 // Any uses of DF need to change to NewDF, with cast.
759 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDF, DGV->getType()));
760 DGV->eraseFromParent();
762 // Internal, LO_ODR, or LO linkage - stick in set to ignore and lazily link.
763 if (SF->hasLocalLinkage() || SF->hasLinkOnceLinkage() ||
764 SF->hasAvailableExternallyLinkage()) {
765 DoNotLinkFromSource.insert(SF);
766 LazilyLinkFunctions.push_back(SF);
770 ValueMap[SF] = NewDF;
774 /// LinkAliasProto - Set up prototypes for any aliases that come over from the
776 bool ModuleLinker::linkAliasProto(GlobalAlias *SGA) {
777 GlobalValue *DGV = getLinkedToGlobal(SGA);
780 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage;
781 bool LinkFromSrc = false;
782 if (getLinkageResult(DGV, SGA, NewLinkage, LinkFromSrc))
786 // Set calculated linkage.
787 DGV->setLinkage(NewLinkage);
789 // Make sure to remember this mapping.
790 ValueMap[SGA] = ConstantExpr::getBitCast(DGV,TypeMap.get(SGA->getType()));
792 // Track the alias from the source module so we don't attempt to remap it.
793 DoNotLinkFromSource.insert(SGA);
799 // If there is no linkage to be performed or we're linking from the source,
801 GlobalAlias *NewDA = new GlobalAlias(TypeMap.get(SGA->getType()),
802 SGA->getLinkage(), SGA->getName(),
804 CopyGVAttributes(NewDA, SGA);
807 // Any uses of DGV need to change to NewDA, with cast.
808 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDA, DGV->getType()));
809 DGV->eraseFromParent();
812 ValueMap[SGA] = NewDA;
816 void ModuleLinker::linkAppendingVarInit(const AppendingVarInfo &AVI) {
817 // Merge the initializer.
818 SmallVector<Constant*, 16> Elements;
819 if (ConstantArray *I = dyn_cast<ConstantArray>(AVI.DstInit)) {
820 for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i)
821 Elements.push_back(I->getOperand(i));
823 assert(isa<ConstantAggregateZero>(AVI.DstInit));
824 ArrayType *DstAT = cast<ArrayType>(AVI.DstInit->getType());
825 Type *EltTy = DstAT->getElementType();
826 Elements.append(DstAT->getNumElements(), Constant::getNullValue(EltTy));
829 Constant *SrcInit = MapValue(AVI.SrcInit, ValueMap, RF_None, &TypeMap);
830 if (const ConstantArray *I = dyn_cast<ConstantArray>(SrcInit)) {
831 for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i)
832 Elements.push_back(I->getOperand(i));
834 assert(isa<ConstantAggregateZero>(SrcInit));
835 ArrayType *SrcAT = cast<ArrayType>(SrcInit->getType());
836 Type *EltTy = SrcAT->getElementType();
837 Elements.append(SrcAT->getNumElements(), Constant::getNullValue(EltTy));
839 ArrayType *NewType = cast<ArrayType>(AVI.NewGV->getType()->getElementType());
840 AVI.NewGV->setInitializer(ConstantArray::get(NewType, Elements));
844 // linkGlobalInits - Update the initializers in the Dest module now that all
845 // globals that may be referenced are in Dest.
846 void ModuleLinker::linkGlobalInits() {
847 // Loop over all of the globals in the src module, mapping them over as we go
848 for (Module::const_global_iterator I = SrcM->global_begin(),
849 E = SrcM->global_end(); I != E; ++I) {
851 // Only process initialized GV's or ones not already in dest.
852 if (!I->hasInitializer() || DoNotLinkFromSource.count(I)) continue;
854 // Grab destination global variable.
855 GlobalVariable *DGV = cast<GlobalVariable>(ValueMap[I]);
856 // Figure out what the initializer looks like in the dest module.
857 DGV->setInitializer(MapValue(I->getInitializer(), ValueMap,
862 // linkFunctionBody - Copy the source function over into the dest function and
863 // fix up references to values. At this point we know that Dest is an external
864 // function, and that Src is not.
865 void ModuleLinker::linkFunctionBody(Function *Dst, Function *Src) {
866 assert(Src && Dst && Dst->isDeclaration() && !Src->isDeclaration());
868 // Go through and convert function arguments over, remembering the mapping.
869 Function::arg_iterator DI = Dst->arg_begin();
870 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end();
872 DI->setName(I->getName()); // Copy the name over.
874 // Add a mapping to our mapping.
878 if (Mode == Linker::DestroySource) {
879 // Splice the body of the source function into the dest function.
880 Dst->getBasicBlockList().splice(Dst->end(), Src->getBasicBlockList());
882 // At this point, all of the instructions and values of the function are now
883 // copied over. The only problem is that they are still referencing values in
884 // the Source function as operands. Loop through all of the operands of the
885 // functions and patch them up to point to the local versions.
886 for (Function::iterator BB = Dst->begin(), BE = Dst->end(); BB != BE; ++BB)
887 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
888 RemapInstruction(I, ValueMap, RF_IgnoreMissingEntries, &TypeMap);
891 // Clone the body of the function into the dest function.
892 SmallVector<ReturnInst*, 8> Returns; // Ignore returns.
893 CloneFunctionInto(Dst, Src, ValueMap, false, Returns);
896 // There is no need to map the arguments anymore.
897 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end();
904 void ModuleLinker::linkAliasBodies() {
905 for (Module::alias_iterator I = SrcM->alias_begin(), E = SrcM->alias_end();
907 if (DoNotLinkFromSource.count(I))
909 if (Constant *Aliasee = I->getAliasee()) {
910 GlobalAlias *DA = cast<GlobalAlias>(ValueMap[I]);
911 DA->setAliasee(MapValue(Aliasee, ValueMap, RF_None, &TypeMap));
916 /// linkNamedMDNodes - Insert all of the named mdnodes in Src into the Dest
918 void ModuleLinker::linkNamedMDNodes() {
919 for (Module::const_named_metadata_iterator I = SrcM->named_metadata_begin(),
920 E = SrcM->named_metadata_end(); I != E; ++I) {
921 NamedMDNode *DestNMD = DstM->getOrInsertNamedMetadata(I->getName());
922 // Add Src elements into Dest node.
923 for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i)
924 DestNMD->addOperand(MapValue(I->getOperand(i), ValueMap,
929 bool ModuleLinker::run() {
930 assert(DstM && "Null Destination module");
931 assert(SrcM && "Null Source Module");
933 // Inherit the target data from the source module if the destination module
934 // doesn't have one already.
935 if (DstM->getDataLayout().empty() && !SrcM->getDataLayout().empty())
936 DstM->setDataLayout(SrcM->getDataLayout());
938 // Copy the target triple from the source to dest if the dest's is empty.
939 if (DstM->getTargetTriple().empty() && !SrcM->getTargetTriple().empty())
940 DstM->setTargetTriple(SrcM->getTargetTriple());
942 if (!SrcM->getDataLayout().empty() && !DstM->getDataLayout().empty() &&
943 SrcM->getDataLayout() != DstM->getDataLayout())
944 errs() << "WARNING: Linking two modules of different data layouts!\n";
945 if (!SrcM->getTargetTriple().empty() &&
946 DstM->getTargetTriple() != SrcM->getTargetTriple()) {
947 errs() << "WARNING: Linking two modules of different target triples: ";
948 if (!SrcM->getModuleIdentifier().empty())
949 errs() << SrcM->getModuleIdentifier() << ": ";
950 errs() << "'" << SrcM->getTargetTriple() << "' and '"
951 << DstM->getTargetTriple() << "'\n";
954 // Append the module inline asm string.
955 if (!SrcM->getModuleInlineAsm().empty()) {
956 if (DstM->getModuleInlineAsm().empty())
957 DstM->setModuleInlineAsm(SrcM->getModuleInlineAsm());
959 DstM->setModuleInlineAsm(DstM->getModuleInlineAsm()+"\n"+
960 SrcM->getModuleInlineAsm());
963 // Update the destination module's dependent libraries list with the libraries
964 // from the source module. There's no opportunity for duplicates here as the
965 // Module ensures that duplicate insertions are discarded.
966 for (Module::lib_iterator SI = SrcM->lib_begin(), SE = SrcM->lib_end();
968 DstM->addLibrary(*SI);
970 // If the source library's module id is in the dependent library list of the
971 // destination library, remove it since that module is now linked in.
972 StringRef ModuleId = SrcM->getModuleIdentifier();
973 if (!ModuleId.empty())
974 DstM->removeLibrary(sys::path::stem(ModuleId));
976 // Loop over all of the linked values to compute type mappings.
977 computeTypeMapping();
979 // Insert all of the globals in src into the DstM module... without linking
980 // initializers (which could refer to functions not yet mapped over).
981 for (Module::global_iterator I = SrcM->global_begin(),
982 E = SrcM->global_end(); I != E; ++I)
983 if (linkGlobalProto(I))
986 // Link the functions together between the two modules, without doing function
987 // bodies... this just adds external function prototypes to the DstM
988 // function... We do this so that when we begin processing function bodies,
989 // all of the global values that may be referenced are available in our
991 for (Module::iterator I = SrcM->begin(), E = SrcM->end(); I != E; ++I)
992 if (linkFunctionProto(I))
995 // If there were any aliases, link them now.
996 for (Module::alias_iterator I = SrcM->alias_begin(),
997 E = SrcM->alias_end(); I != E; ++I)
998 if (linkAliasProto(I))
1001 for (unsigned i = 0, e = AppendingVars.size(); i != e; ++i)
1002 linkAppendingVarInit(AppendingVars[i]);
1004 // Update the initializers in the DstM module now that all globals that may
1005 // be referenced are in DstM.
1008 // Link in the function bodies that are defined in the source module into
1010 for (Module::iterator SF = SrcM->begin(), E = SrcM->end(); SF != E; ++SF) {
1012 // Skip if not linking from source.
1013 if (DoNotLinkFromSource.count(SF)) continue;
1015 // Skip if no body (function is external) or materialize.
1016 if (SF->isDeclaration()) {
1017 if (!SF->isMaterializable())
1019 if (SF->Materialize(&ErrorMsg))
1023 linkFunctionBody(cast<Function>(ValueMap[SF]), SF);
1026 // Resolve all uses of aliases with aliasees.
1029 // Remap all of the named mdnoes in Src into the DstM module. We do this
1030 // after linking GlobalValues so that MDNodes that reference GlobalValues
1031 // are properly remapped.
1034 // Process vector of lazily linked in functions.
1035 bool LinkedInAnyFunctions;
1037 LinkedInAnyFunctions = false;
1039 for(std::vector<Function*>::iterator I = LazilyLinkFunctions.begin(),
1040 E = LazilyLinkFunctions.end(); I != E; ++I) {
1045 Function *DF = cast<Function>(ValueMap[SF]);
1047 if (!DF->use_empty()) {
1049 // Materialize if necessary.
1050 if (SF->isDeclaration()) {
1051 if (!SF->isMaterializable())
1053 if (SF->Materialize(&ErrorMsg))
1057 // Link in function body.
1058 linkFunctionBody(DF, SF);
1060 // "Remove" from vector by setting the element to 0.
1063 // Set flag to indicate we may have more functions to lazily link in
1064 // since we linked in a function.
1065 LinkedInAnyFunctions = true;
1068 } while (LinkedInAnyFunctions);
1070 // Remove any prototypes of functions that were not actually linked in.
1071 for(std::vector<Function*>::iterator I = LazilyLinkFunctions.begin(),
1072 E = LazilyLinkFunctions.end(); I != E; ++I) {
1077 Function *DF = cast<Function>(ValueMap[SF]);
1078 if (DF->use_empty())
1079 DF->eraseFromParent();
1082 // Now that all of the types from the source are used, resolve any structs
1083 // copied over to the dest that didn't exist there.
1084 TypeMap.linkDefinedTypeBodies();
1089 //===----------------------------------------------------------------------===//
1090 // LinkModules entrypoint.
1091 //===----------------------------------------------------------------------===//
1093 // LinkModules - This function links two modules together, with the resulting
1094 // left module modified to be the composite of the two input modules. If an
1095 // error occurs, true is returned and ErrorMsg (if not null) is set to indicate
1096 // the problem. Upon failure, the Dest module could be in a modified state, and
1097 // shouldn't be relied on to be consistent.
1098 bool Linker::LinkModules(Module *Dest, Module *Src, unsigned Mode,
1099 std::string *ErrorMsg) {
1100 ModuleLinker TheLinker(Dest, Src, Mode);
1101 if (TheLinker.run()) {
1102 if (ErrorMsg) *ErrorMsg = TheLinker.ErrorMsg;