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 // Specifically, this:
13 // * Merges global variables between the two modules
14 // * Uninit + Uninit = Init, Init + Uninit = Init, Init + Init = Error if !=
15 // * Merges functions between two modules
17 //===----------------------------------------------------------------------===//
19 #include "llvm/Linker.h"
20 #include "llvm/Constants.h"
21 #include "llvm/DerivedTypes.h"
22 #include "llvm/LLVMContext.h"
23 #include "llvm/Module.h"
24 #include "llvm/TypeSymbolTable.h"
25 #include "llvm/ValueSymbolTable.h"
26 #include "llvm/Instructions.h"
27 #include "llvm/Assembly/Writer.h"
28 #include "llvm/Support/Streams.h"
29 #include "llvm/Support/ErrorHandling.h"
30 #include "llvm/System/Path.h"
31 #include "llvm/ADT/DenseMap.h"
35 // Error - Simple wrapper function to conditionally assign to E and return true.
36 // This just makes error return conditions a little bit simpler...
37 static inline bool Error(std::string *E, const Twine &Message) {
38 if (E) *E = Message.str();
42 // Function: ResolveTypes()
45 // Attempt to link the two specified types together.
48 // DestTy - The type to which we wish to resolve.
49 // SrcTy - The original type which we want to resolve.
52 // DestST - The symbol table in which the new type should be placed.
55 // true - There is an error and the types cannot yet be linked.
58 static bool ResolveTypes(const Type *DestTy, const Type *SrcTy) {
59 if (DestTy == SrcTy) return false; // If already equal, noop
60 assert(DestTy && SrcTy && "Can't handle null types");
62 if (const OpaqueType *OT = dyn_cast<OpaqueType>(DestTy)) {
63 // Type _is_ in module, just opaque...
64 const_cast<OpaqueType*>(OT)->refineAbstractTypeTo(SrcTy);
65 } else if (const OpaqueType *OT = dyn_cast<OpaqueType>(SrcTy)) {
66 const_cast<OpaqueType*>(OT)->refineAbstractTypeTo(DestTy);
68 return true; // Cannot link types... not-equal and neither is opaque.
73 /// LinkerTypeMap - This implements a map of types that is stable
74 /// even if types are resolved/refined to other types. This is not a general
75 /// purpose map, it is specific to the linker's use.
77 class LinkerTypeMap : public AbstractTypeUser {
78 typedef DenseMap<const Type*, PATypeHolder> TheMapTy;
81 LinkerTypeMap(const LinkerTypeMap&); // DO NOT IMPLEMENT
82 void operator=(const LinkerTypeMap&); // DO NOT IMPLEMENT
86 for (DenseMap<const Type*, PATypeHolder>::iterator I = TheMap.begin(),
87 E = TheMap.end(); I != E; ++I)
88 I->first->removeAbstractTypeUser(this);
91 /// lookup - Return the value for the specified type or null if it doesn't
93 const Type *lookup(const Type *Ty) const {
94 TheMapTy::const_iterator I = TheMap.find(Ty);
95 if (I != TheMap.end()) return I->second;
99 /// erase - Remove the specified type, returning true if it was in the set.
100 bool erase(const Type *Ty) {
101 if (!TheMap.erase(Ty))
103 if (Ty->isAbstract())
104 Ty->removeAbstractTypeUser(this);
108 /// insert - This returns true if the pointer was new to the set, false if it
109 /// was already in the set.
110 bool insert(const Type *Src, const Type *Dst) {
111 if (!TheMap.insert(std::make_pair(Src, PATypeHolder(Dst))).second)
112 return false; // Already in map.
113 if (Src->isAbstract())
114 Src->addAbstractTypeUser(this);
119 /// refineAbstractType - The callback method invoked when an abstract type is
120 /// resolved to another type. An object must override this method to update
121 /// its internal state to reference NewType instead of OldType.
123 virtual void refineAbstractType(const DerivedType *OldTy,
125 TheMapTy::iterator I = TheMap.find(OldTy);
126 const Type *DstTy = I->second;
129 if (OldTy->isAbstract())
130 OldTy->removeAbstractTypeUser(this);
132 // Don't reinsert into the map if the key is concrete now.
133 if (NewTy->isAbstract())
134 insert(NewTy, DstTy);
137 /// The other case which AbstractTypeUsers must be aware of is when a type
138 /// makes the transition from being abstract (where it has clients on it's
139 /// AbstractTypeUsers list) to concrete (where it does not). This method
140 /// notifies ATU's when this occurs for a type.
141 virtual void typeBecameConcrete(const DerivedType *AbsTy) {
143 AbsTy->removeAbstractTypeUser(this);
147 virtual void dump() const {
148 cerr << "AbstractTypeSet!\n";
154 // RecursiveResolveTypes - This is just like ResolveTypes, except that it
155 // recurses down into derived types, merging the used types if the parent types
157 static bool RecursiveResolveTypesI(const Type *DstTy, const Type *SrcTy,
158 LinkerTypeMap &Pointers) {
159 if (DstTy == SrcTy) return false; // If already equal, noop
161 // If we found our opaque type, resolve it now!
162 if (isa<OpaqueType>(DstTy) || isa<OpaqueType>(SrcTy))
163 return ResolveTypes(DstTy, SrcTy);
165 // Two types cannot be resolved together if they are of different primitive
166 // type. For example, we cannot resolve an int to a float.
167 if (DstTy->getTypeID() != SrcTy->getTypeID()) return true;
169 // If neither type is abstract, then they really are just different types.
170 if (!DstTy->isAbstract() && !SrcTy->isAbstract())
173 // Otherwise, resolve the used type used by this derived type...
174 switch (DstTy->getTypeID()) {
177 case Type::FunctionTyID: {
178 const FunctionType *DstFT = cast<FunctionType>(DstTy);
179 const FunctionType *SrcFT = cast<FunctionType>(SrcTy);
180 if (DstFT->isVarArg() != SrcFT->isVarArg() ||
181 DstFT->getNumContainedTypes() != SrcFT->getNumContainedTypes())
184 // Use TypeHolder's so recursive resolution won't break us.
185 PATypeHolder ST(SrcFT), DT(DstFT);
186 for (unsigned i = 0, e = DstFT->getNumContainedTypes(); i != e; ++i) {
187 const Type *SE = ST->getContainedType(i), *DE = DT->getContainedType(i);
188 if (SE != DE && RecursiveResolveTypesI(DE, SE, Pointers))
193 case Type::StructTyID: {
194 const StructType *DstST = cast<StructType>(DstTy);
195 const StructType *SrcST = cast<StructType>(SrcTy);
196 if (DstST->getNumContainedTypes() != SrcST->getNumContainedTypes())
199 PATypeHolder ST(SrcST), DT(DstST);
200 for (unsigned i = 0, e = DstST->getNumContainedTypes(); i != e; ++i) {
201 const Type *SE = ST->getContainedType(i), *DE = DT->getContainedType(i);
202 if (SE != DE && RecursiveResolveTypesI(DE, SE, Pointers))
207 case Type::ArrayTyID: {
208 const ArrayType *DAT = cast<ArrayType>(DstTy);
209 const ArrayType *SAT = cast<ArrayType>(SrcTy);
210 if (DAT->getNumElements() != SAT->getNumElements()) return true;
211 return RecursiveResolveTypesI(DAT->getElementType(), SAT->getElementType(),
214 case Type::VectorTyID: {
215 const VectorType *DVT = cast<VectorType>(DstTy);
216 const VectorType *SVT = cast<VectorType>(SrcTy);
217 if (DVT->getNumElements() != SVT->getNumElements()) return true;
218 return RecursiveResolveTypesI(DVT->getElementType(), SVT->getElementType(),
221 case Type::PointerTyID: {
222 const PointerType *DstPT = cast<PointerType>(DstTy);
223 const PointerType *SrcPT = cast<PointerType>(SrcTy);
225 if (DstPT->getAddressSpace() != SrcPT->getAddressSpace())
228 // If this is a pointer type, check to see if we have already seen it. If
229 // so, we are in a recursive branch. Cut off the search now. We cannot use
230 // an associative container for this search, because the type pointers (keys
231 // in the container) change whenever types get resolved.
232 if (SrcPT->isAbstract())
233 if (const Type *ExistingDestTy = Pointers.lookup(SrcPT))
234 return ExistingDestTy != DstPT;
236 if (DstPT->isAbstract())
237 if (const Type *ExistingSrcTy = Pointers.lookup(DstPT))
238 return ExistingSrcTy != SrcPT;
239 // Otherwise, add the current pointers to the vector to stop recursion on
241 if (DstPT->isAbstract())
242 Pointers.insert(DstPT, SrcPT);
243 if (SrcPT->isAbstract())
244 Pointers.insert(SrcPT, DstPT);
246 return RecursiveResolveTypesI(DstPT->getElementType(),
247 SrcPT->getElementType(), Pointers);
252 static bool RecursiveResolveTypes(const Type *DestTy, const Type *SrcTy) {
253 LinkerTypeMap PointerTypes;
254 return RecursiveResolveTypesI(DestTy, SrcTy, PointerTypes);
258 // LinkTypes - Go through the symbol table of the Src module and see if any
259 // types are named in the src module that are not named in the Dst module.
260 // Make sure there are no type name conflicts.
261 static bool LinkTypes(Module *Dest, const Module *Src, std::string *Err) {
262 TypeSymbolTable *DestST = &Dest->getTypeSymbolTable();
263 const TypeSymbolTable *SrcST = &Src->getTypeSymbolTable();
265 // Look for a type plane for Type's...
266 TypeSymbolTable::const_iterator TI = SrcST->begin();
267 TypeSymbolTable::const_iterator TE = SrcST->end();
268 if (TI == TE) return false; // No named types, do nothing.
270 // Some types cannot be resolved immediately because they depend on other
271 // types being resolved to each other first. This contains a list of types we
272 // are waiting to recheck.
273 std::vector<std::string> DelayedTypesToResolve;
275 for ( ; TI != TE; ++TI ) {
276 const std::string &Name = TI->first;
277 const Type *RHS = TI->second;
279 // Check to see if this type name is already in the dest module.
280 Type *Entry = DestST->lookup(Name);
282 // If the name is just in the source module, bring it over to the dest.
285 DestST->insert(Name, const_cast<Type*>(RHS));
286 } else if (ResolveTypes(Entry, RHS)) {
287 // They look different, save the types 'till later to resolve.
288 DelayedTypesToResolve.push_back(Name);
292 // Iteratively resolve types while we can...
293 while (!DelayedTypesToResolve.empty()) {
294 // Loop over all of the types, attempting to resolve them if possible...
295 unsigned OldSize = DelayedTypesToResolve.size();
297 // Try direct resolution by name...
298 for (unsigned i = 0; i != DelayedTypesToResolve.size(); ++i) {
299 const std::string &Name = DelayedTypesToResolve[i];
300 Type *T1 = SrcST->lookup(Name);
301 Type *T2 = DestST->lookup(Name);
302 if (!ResolveTypes(T2, T1)) {
303 // We are making progress!
304 DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i);
309 // Did we not eliminate any types?
310 if (DelayedTypesToResolve.size() == OldSize) {
311 // Attempt to resolve subelements of types. This allows us to merge these
312 // two types: { int* } and { opaque* }
313 for (unsigned i = 0, e = DelayedTypesToResolve.size(); i != e; ++i) {
314 const std::string &Name = DelayedTypesToResolve[i];
315 if (!RecursiveResolveTypes(SrcST->lookup(Name), DestST->lookup(Name))) {
316 // We are making progress!
317 DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i);
319 // Go back to the main loop, perhaps we can resolve directly by name
325 // If we STILL cannot resolve the types, then there is something wrong.
326 if (DelayedTypesToResolve.size() == OldSize) {
327 // Remove the symbol name from the destination.
328 DelayedTypesToResolve.pop_back();
338 static void PrintMap(const std::map<const Value*, Value*> &M) {
339 for (std::map<const Value*, Value*>::const_iterator I = M.begin(), E =M.end();
341 cerr << " Fr: " << (void*)I->first << " ";
343 cerr << " To: " << (void*)I->second << " ";
351 // RemapOperand - Use ValueMap to convert constants from one module to another.
352 static Value *RemapOperand(const Value *In,
353 std::map<const Value*, Value*> &ValueMap,
354 LLVMContext &Context) {
355 std::map<const Value*,Value*>::const_iterator I = ValueMap.find(In);
356 if (I != ValueMap.end())
359 // Check to see if it's a constant that we are interested in transforming.
361 if (const Constant *CPV = dyn_cast<Constant>(In)) {
362 if ((!isa<DerivedType>(CPV->getType()) && !isa<ConstantExpr>(CPV)) ||
363 isa<ConstantInt>(CPV) || isa<ConstantAggregateZero>(CPV))
364 return const_cast<Constant*>(CPV); // Simple constants stay identical.
366 if (const ConstantArray *CPA = dyn_cast<ConstantArray>(CPV)) {
367 std::vector<Constant*> Operands(CPA->getNumOperands());
368 for (unsigned i = 0, e = CPA->getNumOperands(); i != e; ++i)
369 Operands[i] =cast<Constant>(RemapOperand(CPA->getOperand(i), ValueMap,
372 ConstantArray::get(cast<ArrayType>(CPA->getType()), Operands);
373 } else if (const ConstantStruct *CPS = dyn_cast<ConstantStruct>(CPV)) {
374 std::vector<Constant*> Operands(CPS->getNumOperands());
375 for (unsigned i = 0, e = CPS->getNumOperands(); i != e; ++i)
376 Operands[i] =cast<Constant>(RemapOperand(CPS->getOperand(i), ValueMap,
379 ConstantStruct::get(cast<StructType>(CPS->getType()), Operands);
380 } else if (isa<ConstantPointerNull>(CPV) || isa<UndefValue>(CPV)) {
381 Result = const_cast<Constant*>(CPV);
382 } else if (const ConstantVector *CP = dyn_cast<ConstantVector>(CPV)) {
383 std::vector<Constant*> Operands(CP->getNumOperands());
384 for (unsigned i = 0, e = CP->getNumOperands(); i != e; ++i)
385 Operands[i] = cast<Constant>(RemapOperand(CP->getOperand(i), ValueMap,
387 Result = ConstantVector::get(Operands);
388 } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CPV)) {
389 std::vector<Constant*> Ops;
390 for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i)
391 Ops.push_back(cast<Constant>(RemapOperand(CE->getOperand(i),ValueMap,
393 Result = CE->getWithOperands(Ops);
395 assert(!isa<GlobalValue>(CPV) && "Unmapped global?");
396 llvm_unreachable("Unknown type of derived type constant value!");
398 } else if (isa<InlineAsm>(In)) {
399 Result = const_cast<Value*>(In);
402 // Cache the mapping in our local map structure
404 ValueMap[In] = Result;
409 cerr << "LinkModules ValueMap: \n";
412 cerr << "Couldn't remap value: " << (void*)In << " " << *In << "\n";
413 llvm_unreachable("Couldn't remap value!");
418 /// ForceRenaming - The LLVM SymbolTable class autorenames globals that conflict
419 /// in the symbol table. This is good for all clients except for us. Go
420 /// through the trouble to force this back.
421 static void ForceRenaming(GlobalValue *GV, const std::string &Name) {
422 assert(GV->getName() != Name && "Can't force rename to self");
423 ValueSymbolTable &ST = GV->getParent()->getValueSymbolTable();
425 // If there is a conflict, rename the conflict.
426 if (GlobalValue *ConflictGV = cast_or_null<GlobalValue>(ST.lookup(Name))) {
427 assert(ConflictGV->hasLocalLinkage() &&
428 "Not conflicting with a static global, should link instead!");
429 GV->takeName(ConflictGV);
430 ConflictGV->setName(Name); // This will cause ConflictGV to get renamed
431 assert(ConflictGV->getName() != Name && "ForceRenaming didn't work");
433 GV->setName(Name); // Force the name back
437 /// CopyGVAttributes - copy additional attributes (those not needed to construct
438 /// a GlobalValue) from the SrcGV to the DestGV.
439 static void CopyGVAttributes(GlobalValue *DestGV, const GlobalValue *SrcGV) {
440 // Use the maximum alignment, rather than just copying the alignment of SrcGV.
441 unsigned Alignment = std::max(DestGV->getAlignment(), SrcGV->getAlignment());
442 DestGV->copyAttributesFrom(SrcGV);
443 DestGV->setAlignment(Alignment);
446 /// GetLinkageResult - This analyzes the two global values and determines what
447 /// the result will look like in the destination module. In particular, it
448 /// computes the resultant linkage type, computes whether the global in the
449 /// source should be copied over to the destination (replacing the existing
450 /// one), and computes whether this linkage is an error or not. It also performs
451 /// visibility checks: we cannot link together two symbols with different
453 static bool GetLinkageResult(GlobalValue *Dest, const GlobalValue *Src,
454 GlobalValue::LinkageTypes <, bool &LinkFromSrc,
456 assert((!Dest || !Src->hasLocalLinkage()) &&
457 "If Src has internal linkage, Dest shouldn't be set!");
459 // Linking something to nothing.
461 LT = Src->getLinkage();
462 } else if (Src->isDeclaration()) {
463 // If Src is external or if both Src & Dest are external.. Just link the
464 // external globals, we aren't adding anything.
465 if (Src->hasDLLImportLinkage()) {
466 // If one of GVs has DLLImport linkage, result should be dllimport'ed.
467 if (Dest->isDeclaration()) {
469 LT = Src->getLinkage();
471 } else if (Dest->hasExternalWeakLinkage()) {
472 // If the Dest is weak, use the source linkage.
474 LT = Src->getLinkage();
477 LT = Dest->getLinkage();
479 } else if (Dest->isDeclaration() && !Dest->hasDLLImportLinkage()) {
480 // If Dest is external but Src is not:
482 LT = Src->getLinkage();
483 } else if (Src->hasAppendingLinkage() || Dest->hasAppendingLinkage()) {
484 if (Src->getLinkage() != Dest->getLinkage())
485 return Error(Err, "Linking globals named '" + Src->getName() +
486 "': can only link appending global with another appending global!");
487 LinkFromSrc = true; // Special cased.
488 LT = Src->getLinkage();
489 } else if (Src->isWeakForLinker()) {
490 // At this point we know that Dest has LinkOnce, External*, Weak, Common,
492 if (Dest->hasExternalWeakLinkage() ||
493 Dest->hasAvailableExternallyLinkage() ||
494 (Dest->hasLinkOnceLinkage() &&
495 (Src->hasWeakLinkage() || Src->hasCommonLinkage()))) {
497 LT = Src->getLinkage();
500 LT = Dest->getLinkage();
502 } else if (Dest->isWeakForLinker()) {
503 // At this point we know that Src has External* or DLL* linkage.
504 if (Src->hasExternalWeakLinkage()) {
506 LT = Dest->getLinkage();
509 LT = GlobalValue::ExternalLinkage;
512 assert((Dest->hasExternalLinkage() ||
513 Dest->hasDLLImportLinkage() ||
514 Dest->hasDLLExportLinkage() ||
515 Dest->hasExternalWeakLinkage()) &&
516 (Src->hasExternalLinkage() ||
517 Src->hasDLLImportLinkage() ||
518 Src->hasDLLExportLinkage() ||
519 Src->hasExternalWeakLinkage()) &&
520 "Unexpected linkage type!");
521 return Error(Err, "Linking globals named '" + Src->getName() +
522 "': symbol multiply defined!");
526 if (Dest && Src->getVisibility() != Dest->getVisibility())
527 if (!Src->isDeclaration() && !Dest->isDeclaration())
528 return Error(Err, "Linking globals named '" + Src->getName() +
529 "': symbols have different visibilities!");
533 // LinkGlobals - Loop through the global variables in the src module and merge
534 // them into the dest module.
535 static bool LinkGlobals(Module *Dest, const Module *Src,
536 std::map<const Value*, Value*> &ValueMap,
537 std::multimap<std::string, GlobalVariable *> &AppendingVars,
539 ValueSymbolTable &DestSymTab = Dest->getValueSymbolTable();
540 LLVMContext &Context = Dest->getContext();
542 // Loop over all of the globals in the src module, mapping them over as we go
543 for (Module::const_global_iterator I = Src->global_begin(),
544 E = Src->global_end(); I != E; ++I) {
545 const GlobalVariable *SGV = I;
546 GlobalValue *DGV = 0;
548 // Check to see if may have to link the global with the global, alias or
550 if (SGV->hasName() && !SGV->hasLocalLinkage())
551 DGV = cast_or_null<GlobalValue>(DestSymTab.lookup(SGV->getName()));
553 // If we found a global with the same name in the dest module, but it has
554 // internal linkage, we are really not doing any linkage here.
555 if (DGV && DGV->hasLocalLinkage())
558 // If types don't agree due to opaque types, try to resolve them.
559 if (DGV && DGV->getType() != SGV->getType())
560 RecursiveResolveTypes(SGV->getType(), DGV->getType());
562 assert((SGV->hasInitializer() || SGV->hasExternalWeakLinkage() ||
563 SGV->hasExternalLinkage() || SGV->hasDLLImportLinkage()) &&
564 "Global must either be external or have an initializer!");
566 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage;
567 bool LinkFromSrc = false;
568 if (GetLinkageResult(DGV, SGV, NewLinkage, LinkFromSrc, Err))
572 // No linking to be performed, simply create an identical version of the
573 // symbol over in the dest module... the initializer will be filled in
574 // later by LinkGlobalInits.
575 GlobalVariable *NewDGV =
576 new GlobalVariable(*Dest, SGV->getType()->getElementType(),
577 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
578 SGV->getName(), 0, false,
579 SGV->getType()->getAddressSpace());
580 // Propagate alignment, visibility and section info.
581 CopyGVAttributes(NewDGV, SGV);
583 // If the LLVM runtime renamed the global, but it is an externally visible
584 // symbol, DGV must be an existing global with internal linkage. Rename
586 if (!NewDGV->hasLocalLinkage() && NewDGV->getName() != SGV->getName())
587 ForceRenaming(NewDGV, SGV->getName());
589 // Make sure to remember this mapping.
590 ValueMap[SGV] = NewDGV;
592 // Keep track that this is an appending variable.
593 if (SGV->hasAppendingLinkage())
594 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV));
598 // If the visibilities of the symbols disagree and the destination is a
599 // prototype, take the visibility of its input.
600 if (DGV->isDeclaration())
601 DGV->setVisibility(SGV->getVisibility());
603 if (DGV->hasAppendingLinkage()) {
604 // No linking is performed yet. Just insert a new copy of the global, and
605 // keep track of the fact that it is an appending variable in the
606 // AppendingVars map. The name is cleared out so that no linkage is
608 GlobalVariable *NewDGV =
609 new GlobalVariable(*Dest, SGV->getType()->getElementType(),
610 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
612 SGV->getType()->getAddressSpace());
614 // Set alignment allowing CopyGVAttributes merge it with alignment of SGV.
615 NewDGV->setAlignment(DGV->getAlignment());
616 // Propagate alignment, section and visibility info.
617 CopyGVAttributes(NewDGV, SGV);
619 // Make sure to remember this mapping...
620 ValueMap[SGV] = NewDGV;
622 // Keep track that this is an appending variable...
623 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV));
628 if (isa<GlobalAlias>(DGV))
629 return Error(Err, "Global-Alias Collision on '" + SGV->getName() +
630 "': symbol multiple defined");
632 // If the types don't match, and if we are to link from the source, nuke
633 // DGV and create a new one of the appropriate type. Note that the thing
634 // we are replacing may be a function (if a prototype, weak, etc) or a
636 GlobalVariable *NewDGV =
637 new GlobalVariable(*Dest, SGV->getType()->getElementType(),
638 SGV->isConstant(), NewLinkage, /*init*/0,
639 DGV->getName(), 0, false,
640 SGV->getType()->getAddressSpace());
642 // Propagate alignment, section, and visibility info.
643 CopyGVAttributes(NewDGV, SGV);
644 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDGV,
647 // DGV will conflict with NewDGV because they both had the same
648 // name. We must erase this now so ForceRenaming doesn't assert
649 // because DGV might not have internal linkage.
650 if (GlobalVariable *Var = dyn_cast<GlobalVariable>(DGV))
651 Var->eraseFromParent();
653 cast<Function>(DGV)->eraseFromParent();
656 // If the symbol table renamed the global, but it is an externally visible
657 // symbol, DGV must be an existing global with internal linkage. Rename.
658 if (NewDGV->getName() != SGV->getName() && !NewDGV->hasLocalLinkage())
659 ForceRenaming(NewDGV, SGV->getName());
661 // Inherit const as appropriate.
662 NewDGV->setConstant(SGV->isConstant());
664 // Make sure to remember this mapping.
665 ValueMap[SGV] = NewDGV;
669 // Not "link from source", keep the one in the DestModule and remap the
672 // Special case for const propagation.
673 if (GlobalVariable *DGVar = dyn_cast<GlobalVariable>(DGV))
674 if (DGVar->isDeclaration() && SGV->isConstant() && !DGVar->isConstant())
675 DGVar->setConstant(true);
677 // SGV is global, but DGV is alias.
678 if (isa<GlobalAlias>(DGV)) {
679 // The only valid mappings are:
680 // - SGV is external declaration, which is effectively a no-op.
681 // - SGV is weak, when we just need to throw SGV out.
682 if (!SGV->isDeclaration() && !SGV->isWeakForLinker())
683 return Error(Err, "Global-Alias Collision on '" + SGV->getName() +
684 "': symbol multiple defined");
687 // Set calculated linkage
688 DGV->setLinkage(NewLinkage);
690 // Make sure to remember this mapping...
691 ValueMap[SGV] = ConstantExpr::getBitCast(DGV, SGV->getType());
696 static GlobalValue::LinkageTypes
697 CalculateAliasLinkage(const GlobalValue *SGV, const GlobalValue *DGV) {
698 GlobalValue::LinkageTypes SL = SGV->getLinkage();
699 GlobalValue::LinkageTypes DL = DGV->getLinkage();
700 if (SL == GlobalValue::ExternalLinkage || DL == GlobalValue::ExternalLinkage)
701 return GlobalValue::ExternalLinkage;
702 else if (SL == GlobalValue::WeakAnyLinkage ||
703 DL == GlobalValue::WeakAnyLinkage)
704 return GlobalValue::WeakAnyLinkage;
705 else if (SL == GlobalValue::WeakODRLinkage ||
706 DL == GlobalValue::WeakODRLinkage)
707 return GlobalValue::WeakODRLinkage;
708 else if (SL == GlobalValue::InternalLinkage &&
709 DL == GlobalValue::InternalLinkage)
710 return GlobalValue::InternalLinkage;
711 else if (SL == GlobalValue::LinkerPrivateLinkage &&
712 DL == GlobalValue::LinkerPrivateLinkage)
713 return GlobalValue::LinkerPrivateLinkage;
715 assert (SL == GlobalValue::PrivateLinkage &&
716 DL == GlobalValue::PrivateLinkage && "Unexpected linkage type");
717 return GlobalValue::PrivateLinkage;
721 // LinkAlias - Loop through the alias in the src module and link them into the
722 // dest module. We're assuming, that all functions/global variables were already
724 static bool LinkAlias(Module *Dest, const Module *Src,
725 std::map<const Value*, Value*> &ValueMap,
727 LLVMContext &Context = Dest->getContext();
729 // Loop over all alias in the src module
730 for (Module::const_alias_iterator I = Src->alias_begin(),
731 E = Src->alias_end(); I != E; ++I) {
732 const GlobalAlias *SGA = I;
733 const GlobalValue *SAliasee = SGA->getAliasedGlobal();
734 GlobalAlias *NewGA = NULL;
736 // Globals were already linked, thus we can just query ValueMap for variant
737 // of SAliasee in Dest.
738 std::map<const Value*,Value*>::const_iterator VMI = ValueMap.find(SAliasee);
739 assert(VMI != ValueMap.end() && "Aliasee not linked");
740 GlobalValue* DAliasee = cast<GlobalValue>(VMI->second);
741 GlobalValue* DGV = NULL;
743 // Try to find something 'similar' to SGA in destination module.
744 if (!DGV && !SGA->hasLocalLinkage()) {
745 DGV = Dest->getNamedAlias(SGA->getName());
747 // If types don't agree due to opaque types, try to resolve them.
748 if (DGV && DGV->getType() != SGA->getType())
749 RecursiveResolveTypes(SGA->getType(), DGV->getType());
752 if (!DGV && !SGA->hasLocalLinkage()) {
753 DGV = Dest->getGlobalVariable(SGA->getName());
755 // If types don't agree due to opaque types, try to resolve them.
756 if (DGV && DGV->getType() != SGA->getType())
757 RecursiveResolveTypes(SGA->getType(), DGV->getType());
760 if (!DGV && !SGA->hasLocalLinkage()) {
761 DGV = Dest->getFunction(SGA->getName());
763 // If types don't agree due to opaque types, try to resolve them.
764 if (DGV && DGV->getType() != SGA->getType())
765 RecursiveResolveTypes(SGA->getType(), DGV->getType());
768 // No linking to be performed on internal stuff.
769 if (DGV && DGV->hasLocalLinkage())
772 if (GlobalAlias *DGA = dyn_cast_or_null<GlobalAlias>(DGV)) {
773 // Types are known to be the same, check whether aliasees equal. As
774 // globals are already linked we just need query ValueMap to find the
776 if (DAliasee == DGA->getAliasedGlobal()) {
777 // This is just two copies of the same alias. Propagate linkage, if
779 DGA->setLinkage(CalculateAliasLinkage(SGA, DGA));
782 // Proceed to 'common' steps
784 return Error(Err, "Alias Collision on '" + SGA->getName()+
785 "': aliases have different aliasees");
786 } else if (GlobalVariable *DGVar = dyn_cast_or_null<GlobalVariable>(DGV)) {
787 // The only allowed way is to link alias with external declaration or weak
789 if (DGVar->isDeclaration() || DGVar->isWeakForLinker()) {
790 // But only if aliasee is global too...
791 if (!isa<GlobalVariable>(DAliasee))
792 return Error(Err, "Global-Alias Collision on '" + SGA->getName() +
793 "': aliasee is not global variable");
795 NewGA = new GlobalAlias(SGA->getType(), SGA->getLinkage(),
796 SGA->getName(), DAliasee, Dest);
797 CopyGVAttributes(NewGA, SGA);
799 // Any uses of DGV need to change to NewGA, with cast, if needed.
800 if (SGA->getType() != DGVar->getType())
801 DGVar->replaceAllUsesWith(ConstantExpr::getBitCast(NewGA,
804 DGVar->replaceAllUsesWith(NewGA);
806 // DGVar will conflict with NewGA because they both had the same
807 // name. We must erase this now so ForceRenaming doesn't assert
808 // because DGV might not have internal linkage.
809 DGVar->eraseFromParent();
811 // Proceed to 'common' steps
813 return Error(Err, "Global-Alias Collision on '" + SGA->getName() +
814 "': symbol multiple defined");
815 } else if (Function *DF = dyn_cast_or_null<Function>(DGV)) {
816 // The only allowed way is to link alias with external declaration or weak
818 if (DF->isDeclaration() || DF->isWeakForLinker()) {
819 // But only if aliasee is function too...
820 if (!isa<Function>(DAliasee))
821 return Error(Err, "Function-Alias Collision on '" + SGA->getName() +
822 "': aliasee is not function");
824 NewGA = new GlobalAlias(SGA->getType(), SGA->getLinkage(),
825 SGA->getName(), DAliasee, Dest);
826 CopyGVAttributes(NewGA, SGA);
828 // Any uses of DF need to change to NewGA, with cast, if needed.
829 if (SGA->getType() != DF->getType())
830 DF->replaceAllUsesWith(ConstantExpr::getBitCast(NewGA,
833 DF->replaceAllUsesWith(NewGA);
835 // DF will conflict with NewGA because they both had the same
836 // name. We must erase this now so ForceRenaming doesn't assert
837 // because DF might not have internal linkage.
838 DF->eraseFromParent();
840 // Proceed to 'common' steps
842 return Error(Err, "Function-Alias Collision on '" + SGA->getName() +
843 "': symbol multiple defined");
845 // No linking to be performed, simply create an identical version of the
846 // alias over in the dest module...
848 NewGA = new GlobalAlias(SGA->getType(), SGA->getLinkage(),
849 SGA->getName(), DAliasee, Dest);
850 CopyGVAttributes(NewGA, SGA);
852 // Proceed to 'common' steps
855 assert(NewGA && "No alias was created in destination module!");
857 // If the symbol table renamed the alias, but it is an externally visible
858 // symbol, DGA must be an global value with internal linkage. Rename it.
859 if (NewGA->getName() != SGA->getName() &&
860 !NewGA->hasLocalLinkage())
861 ForceRenaming(NewGA, SGA->getName());
863 // Remember this mapping so uses in the source module get remapped
864 // later by RemapOperand.
865 ValueMap[SGA] = NewGA;
872 // LinkGlobalInits - Update the initializers in the Dest module now that all
873 // globals that may be referenced are in Dest.
874 static bool LinkGlobalInits(Module *Dest, const Module *Src,
875 std::map<const Value*, Value*> &ValueMap,
877 // Loop over all of the globals in the src module, mapping them over as we go
878 for (Module::const_global_iterator I = Src->global_begin(),
879 E = Src->global_end(); I != E; ++I) {
880 const GlobalVariable *SGV = I;
882 if (SGV->hasInitializer()) { // Only process initialized GV's
883 // Figure out what the initializer looks like in the dest module...
885 cast<Constant>(RemapOperand(SGV->getInitializer(), ValueMap,
886 Dest->getContext()));
887 // Grab destination global variable or alias.
888 GlobalValue *DGV = cast<GlobalValue>(ValueMap[SGV]->stripPointerCasts());
890 // If dest if global variable, check that initializers match.
891 if (GlobalVariable *DGVar = dyn_cast<GlobalVariable>(DGV)) {
892 if (DGVar->hasInitializer()) {
893 if (SGV->hasExternalLinkage()) {
894 if (DGVar->getInitializer() != SInit)
895 return Error(Err, "Global Variable Collision on '" +
897 "': global variables have different initializers");
898 } else if (DGVar->isWeakForLinker()) {
899 // Nothing is required, mapped values will take the new global
901 } else if (SGV->isWeakForLinker()) {
902 // Nothing is required, mapped values will take the new global
904 } else if (DGVar->hasAppendingLinkage()) {
905 llvm_unreachable("Appending linkage unimplemented!");
907 llvm_unreachable("Unknown linkage!");
910 // Copy the initializer over now...
911 DGVar->setInitializer(SInit);
914 // Destination is alias, the only valid situation is when source is
915 // weak. Also, note, that we already checked linkage in LinkGlobals(),
916 // thus we assert here.
917 // FIXME: Should we weaken this assumption, 'dereference' alias and
918 // check for initializer of aliasee?
919 assert(SGV->isWeakForLinker());
926 // LinkFunctionProtos - Link the functions together between the two modules,
927 // without doing function bodies... this just adds external function prototypes
928 // to the Dest function...
930 static bool LinkFunctionProtos(Module *Dest, const Module *Src,
931 std::map<const Value*, Value*> &ValueMap,
933 ValueSymbolTable &DestSymTab = Dest->getValueSymbolTable();
934 LLVMContext &Context = Dest->getContext();
936 // Loop over all of the functions in the src module, mapping them over
937 for (Module::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) {
938 const Function *SF = I; // SrcFunction
939 GlobalValue *DGV = 0;
941 // Check to see if may have to link the function with the global, alias or
943 if (SF->hasName() && !SF->hasLocalLinkage())
944 DGV = cast_or_null<GlobalValue>(DestSymTab.lookup(SF->getName()));
946 // If we found a global with the same name in the dest module, but it has
947 // internal linkage, we are really not doing any linkage here.
948 if (DGV && DGV->hasLocalLinkage())
951 // If types don't agree due to opaque types, try to resolve them.
952 if (DGV && DGV->getType() != SF->getType())
953 RecursiveResolveTypes(SF->getType(), DGV->getType());
955 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage;
956 bool LinkFromSrc = false;
957 if (GetLinkageResult(DGV, SF, NewLinkage, LinkFromSrc, Err))
960 // If there is no linkage to be performed, just bring over SF without
963 // Function does not already exist, simply insert an function signature
964 // identical to SF into the dest module.
965 Function *NewDF = Function::Create(SF->getFunctionType(),
967 SF->getName(), Dest);
968 CopyGVAttributes(NewDF, SF);
970 // If the LLVM runtime renamed the function, but it is an externally
971 // visible symbol, DF must be an existing function with internal linkage.
973 if (!NewDF->hasLocalLinkage() && NewDF->getName() != SF->getName())
974 ForceRenaming(NewDF, SF->getName());
976 // ... and remember this mapping...
977 ValueMap[SF] = NewDF;
981 // If the visibilities of the symbols disagree and the destination is a
982 // prototype, take the visibility of its input.
983 if (DGV->isDeclaration())
984 DGV->setVisibility(SF->getVisibility());
987 if (isa<GlobalAlias>(DGV))
988 return Error(Err, "Function-Alias Collision on '" + SF->getName() +
989 "': symbol multiple defined");
991 // We have a definition of the same name but different type in the
992 // source module. Copy the prototype to the destination and replace
993 // uses of the destination's prototype with the new prototype.
994 Function *NewDF = Function::Create(SF->getFunctionType(), NewLinkage,
995 SF->getName(), Dest);
996 CopyGVAttributes(NewDF, SF);
998 // Any uses of DF need to change to NewDF, with cast
999 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDF,
1002 // DF will conflict with NewDF because they both had the same. We must
1003 // erase this now so ForceRenaming doesn't assert because DF might
1004 // not have internal linkage.
1005 if (GlobalVariable *Var = dyn_cast<GlobalVariable>(DGV))
1006 Var->eraseFromParent();
1008 cast<Function>(DGV)->eraseFromParent();
1010 // If the symbol table renamed the function, but it is an externally
1011 // visible symbol, DF must be an existing function with internal
1012 // linkage. Rename it.
1013 if (NewDF->getName() != SF->getName() && !NewDF->hasLocalLinkage())
1014 ForceRenaming(NewDF, SF->getName());
1016 // Remember this mapping so uses in the source module get remapped
1017 // later by RemapOperand.
1018 ValueMap[SF] = NewDF;
1022 // Not "link from source", keep the one in the DestModule and remap the
1025 if (isa<GlobalAlias>(DGV)) {
1026 // The only valid mappings are:
1027 // - SF is external declaration, which is effectively a no-op.
1028 // - SF is weak, when we just need to throw SF out.
1029 if (!SF->isDeclaration() && !SF->isWeakForLinker())
1030 return Error(Err, "Function-Alias Collision on '" + SF->getName() +
1031 "': symbol multiple defined");
1034 // Set calculated linkage
1035 DGV->setLinkage(NewLinkage);
1037 // Make sure to remember this mapping.
1038 ValueMap[SF] = ConstantExpr::getBitCast(DGV, SF->getType());
1043 // LinkFunctionBody - Copy the source function over into the dest function and
1044 // fix up references to values. At this point we know that Dest is an external
1045 // function, and that Src is not.
1046 static bool LinkFunctionBody(Function *Dest, Function *Src,
1047 std::map<const Value*, Value*> &ValueMap,
1049 assert(Src && Dest && Dest->isDeclaration() && !Src->isDeclaration());
1051 // Go through and convert function arguments over, remembering the mapping.
1052 Function::arg_iterator DI = Dest->arg_begin();
1053 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end();
1054 I != E; ++I, ++DI) {
1055 DI->setName(I->getName()); // Copy the name information over...
1057 // Add a mapping to our local map
1061 // Splice the body of the source function into the dest function.
1062 Dest->getBasicBlockList().splice(Dest->end(), Src->getBasicBlockList());
1064 // At this point, all of the instructions and values of the function are now
1065 // copied over. The only problem is that they are still referencing values in
1066 // the Source function as operands. Loop through all of the operands of the
1067 // functions and patch them up to point to the local versions...
1069 for (Function::iterator BB = Dest->begin(), BE = Dest->end(); BB != BE; ++BB)
1070 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
1071 for (Instruction::op_iterator OI = I->op_begin(), OE = I->op_end();
1073 if (!isa<Instruction>(*OI) && !isa<BasicBlock>(*OI))
1074 *OI = RemapOperand(*OI, ValueMap, Dest->getContext());
1076 // There is no need to map the arguments anymore.
1077 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end();
1085 // LinkFunctionBodies - Link in the function bodies that are defined in the
1086 // source module into the DestModule. This consists basically of copying the
1087 // function over and fixing up references to values.
1088 static bool LinkFunctionBodies(Module *Dest, Module *Src,
1089 std::map<const Value*, Value*> &ValueMap,
1092 // Loop over all of the functions in the src module, mapping them over as we
1094 for (Module::iterator SF = Src->begin(), E = Src->end(); SF != E; ++SF) {
1095 if (!SF->isDeclaration()) { // No body if function is external
1096 Function *DF = dyn_cast<Function>(ValueMap[SF]); // Destination function
1098 // DF not external SF external?
1099 if (DF && DF->isDeclaration())
1100 // Only provide the function body if there isn't one already.
1101 if (LinkFunctionBody(DF, SF, ValueMap, Err))
1108 // LinkAppendingVars - If there were any appending global variables, link them
1109 // together now. Return true on error.
1110 static bool LinkAppendingVars(Module *M,
1111 std::multimap<std::string, GlobalVariable *> &AppendingVars,
1112 std::string *ErrorMsg) {
1113 if (AppendingVars.empty()) return false; // Nothing to do.
1115 LLVMContext &Context = M->getContext();
1117 // Loop over the multimap of appending vars, processing any variables with the
1118 // same name, forming a new appending global variable with both of the
1119 // initializers merged together, then rewrite references to the old variables
1121 std::vector<Constant*> Inits;
1122 while (AppendingVars.size() > 1) {
1123 // Get the first two elements in the map...
1124 std::multimap<std::string,
1125 GlobalVariable*>::iterator Second = AppendingVars.begin(), First=Second++;
1127 // If the first two elements are for different names, there is no pair...
1128 // Otherwise there is a pair, so link them together...
1129 if (First->first == Second->first) {
1130 GlobalVariable *G1 = First->second, *G2 = Second->second;
1131 const ArrayType *T1 = cast<ArrayType>(G1->getType()->getElementType());
1132 const ArrayType *T2 = cast<ArrayType>(G2->getType()->getElementType());
1134 // Check to see that they two arrays agree on type...
1135 if (T1->getElementType() != T2->getElementType())
1136 return Error(ErrorMsg,
1137 "Appending variables with different element types need to be linked!");
1138 if (G1->isConstant() != G2->isConstant())
1139 return Error(ErrorMsg,
1140 "Appending variables linked with different const'ness!");
1142 if (G1->getAlignment() != G2->getAlignment())
1143 return Error(ErrorMsg,
1144 "Appending variables with different alignment need to be linked!");
1146 if (G1->getVisibility() != G2->getVisibility())
1147 return Error(ErrorMsg,
1148 "Appending variables with different visibility need to be linked!");
1150 if (G1->getSection() != G2->getSection())
1151 return Error(ErrorMsg,
1152 "Appending variables with different section name need to be linked!");
1154 unsigned NewSize = T1->getNumElements() + T2->getNumElements();
1155 ArrayType *NewType = Context.getArrayType(T1->getElementType(),
1158 G1->setName(""); // Clear G1's name in case of a conflict!
1160 // Create the new global variable...
1161 GlobalVariable *NG =
1162 new GlobalVariable(*M, NewType, G1->isConstant(), G1->getLinkage(),
1163 /*init*/0, First->first, 0, G1->isThreadLocal(),
1164 G1->getType()->getAddressSpace());
1166 // Propagate alignment, visibility and section info.
1167 CopyGVAttributes(NG, G1);
1169 // Merge the initializer...
1170 Inits.reserve(NewSize);
1171 if (ConstantArray *I = dyn_cast<ConstantArray>(G1->getInitializer())) {
1172 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i)
1173 Inits.push_back(I->getOperand(i));
1175 assert(isa<ConstantAggregateZero>(G1->getInitializer()));
1176 Constant *CV = Context.getNullValue(T1->getElementType());
1177 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i)
1178 Inits.push_back(CV);
1180 if (ConstantArray *I = dyn_cast<ConstantArray>(G2->getInitializer())) {
1181 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i)
1182 Inits.push_back(I->getOperand(i));
1184 assert(isa<ConstantAggregateZero>(G2->getInitializer()));
1185 Constant *CV = Context.getNullValue(T2->getElementType());
1186 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i)
1187 Inits.push_back(CV);
1189 NG->setInitializer(ConstantArray::get(NewType, Inits));
1192 // Replace any uses of the two global variables with uses of the new
1195 // FIXME: This should rewrite simple/straight-forward uses such as
1196 // getelementptr instructions to not use the Cast!
1197 G1->replaceAllUsesWith(ConstantExpr::getBitCast(NG,
1199 G2->replaceAllUsesWith(ConstantExpr::getBitCast(NG,
1202 // Remove the two globals from the module now...
1203 M->getGlobalList().erase(G1);
1204 M->getGlobalList().erase(G2);
1206 // Put the new global into the AppendingVars map so that we can handle
1207 // linking of more than two vars...
1208 Second->second = NG;
1210 AppendingVars.erase(First);
1216 static bool ResolveAliases(Module *Dest) {
1217 for (Module::alias_iterator I = Dest->alias_begin(), E = Dest->alias_end();
1219 if (const GlobalValue *GV = I->resolveAliasedGlobal())
1220 if (GV != I && !GV->isDeclaration())
1221 I->replaceAllUsesWith(const_cast<GlobalValue*>(GV));
1226 // LinkModules - This function links two modules together, with the resulting
1227 // left module modified to be the composite of the two input modules. If an
1228 // error occurs, true is returned and ErrorMsg (if not null) is set to indicate
1229 // the problem. Upon failure, the Dest module could be in a modified state, and
1230 // shouldn't be relied on to be consistent.
1232 Linker::LinkModules(Module *Dest, Module *Src, std::string *ErrorMsg) {
1233 assert(Dest != 0 && "Invalid Destination module");
1234 assert(Src != 0 && "Invalid Source Module");
1236 if (Dest->getDataLayout().empty()) {
1237 if (!Src->getDataLayout().empty()) {
1238 Dest->setDataLayout(Src->getDataLayout());
1240 std::string DataLayout;
1242 if (Dest->getEndianness() == Module::AnyEndianness) {
1243 if (Src->getEndianness() == Module::BigEndian)
1244 DataLayout.append("E");
1245 else if (Src->getEndianness() == Module::LittleEndian)
1246 DataLayout.append("e");
1249 if (Dest->getPointerSize() == Module::AnyPointerSize) {
1250 if (Src->getPointerSize() == Module::Pointer64)
1251 DataLayout.append(DataLayout.length() == 0 ? "p:64:64" : "-p:64:64");
1252 else if (Src->getPointerSize() == Module::Pointer32)
1253 DataLayout.append(DataLayout.length() == 0 ? "p:32:32" : "-p:32:32");
1255 Dest->setDataLayout(DataLayout);
1259 // Copy the target triple from the source to dest if the dest's is empty.
1260 if (Dest->getTargetTriple().empty() && !Src->getTargetTriple().empty())
1261 Dest->setTargetTriple(Src->getTargetTriple());
1263 if (!Src->getDataLayout().empty() && !Dest->getDataLayout().empty() &&
1264 Src->getDataLayout() != Dest->getDataLayout())
1265 cerr << "WARNING: Linking two modules of different data layouts!\n";
1266 if (!Src->getTargetTriple().empty() &&
1267 Dest->getTargetTriple() != Src->getTargetTriple())
1268 cerr << "WARNING: Linking two modules of different target triples!\n";
1270 // Append the module inline asm string.
1271 if (!Src->getModuleInlineAsm().empty()) {
1272 if (Dest->getModuleInlineAsm().empty())
1273 Dest->setModuleInlineAsm(Src->getModuleInlineAsm());
1275 Dest->setModuleInlineAsm(Dest->getModuleInlineAsm()+"\n"+
1276 Src->getModuleInlineAsm());
1279 // Update the destination module's dependent libraries list with the libraries
1280 // from the source module. There's no opportunity for duplicates here as the
1281 // Module ensures that duplicate insertions are discarded.
1282 for (Module::lib_iterator SI = Src->lib_begin(), SE = Src->lib_end();
1284 Dest->addLibrary(*SI);
1286 // LinkTypes - Go through the symbol table of the Src module and see if any
1287 // types are named in the src module that are not named in the Dst module.
1288 // Make sure there are no type name conflicts.
1289 if (LinkTypes(Dest, Src, ErrorMsg))
1292 // ValueMap - Mapping of values from what they used to be in Src, to what they
1294 std::map<const Value*, Value*> ValueMap;
1296 // AppendingVars - Keep track of global variables in the destination module
1297 // with appending linkage. After the module is linked together, they are
1298 // appended and the module is rewritten.
1299 std::multimap<std::string, GlobalVariable *> AppendingVars;
1300 for (Module::global_iterator I = Dest->global_begin(), E = Dest->global_end();
1302 // Add all of the appending globals already in the Dest module to
1304 if (I->hasAppendingLinkage())
1305 AppendingVars.insert(std::make_pair(I->getName(), I));
1308 // Insert all of the globals in src into the Dest module... without linking
1309 // initializers (which could refer to functions not yet mapped over).
1310 if (LinkGlobals(Dest, Src, ValueMap, AppendingVars, ErrorMsg))
1313 // Link the functions together between the two modules, without doing function
1314 // bodies... this just adds external function prototypes to the Dest
1315 // function... We do this so that when we begin processing function bodies,
1316 // all of the global values that may be referenced are available in our
1318 if (LinkFunctionProtos(Dest, Src, ValueMap, ErrorMsg))
1321 // If there were any alias, link them now. We really need to do this now,
1322 // because all of the aliases that may be referenced need to be available in
1324 if (LinkAlias(Dest, Src, ValueMap, ErrorMsg)) return true;
1326 // Update the initializers in the Dest module now that all globals that may
1327 // be referenced are in Dest.
1328 if (LinkGlobalInits(Dest, Src, ValueMap, ErrorMsg)) return true;
1330 // Link in the function bodies that are defined in the source module into the
1331 // DestModule. This consists basically of copying the function over and
1332 // fixing up references to values.
1333 if (LinkFunctionBodies(Dest, Src, ValueMap, ErrorMsg)) return true;
1335 // If there were any appending global variables, link them together now.
1336 if (LinkAppendingVars(Dest, AppendingVars, ErrorMsg)) return true;
1338 // Resolve all uses of aliases with aliasees
1339 if (ResolveAliases(Dest)) return true;
1341 // If the source library's module id is in the dependent library list of the
1342 // destination library, remove it since that module is now linked in.
1344 modId.set(Src->getModuleIdentifier());
1345 if (!modId.isEmpty())
1346 Dest->removeLibrary(modId.getBasename());