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/Module.h"
23 #include "llvm/TypeSymbolTable.h"
24 #include "llvm/ValueSymbolTable.h"
25 #include "llvm/Instructions.h"
26 #include "llvm/Assembly/Writer.h"
27 #include "llvm/Support/Streams.h"
28 #include "llvm/System/Path.h"
32 // Error - Simple wrapper function to conditionally assign to E and return true.
33 // This just makes error return conditions a little bit simpler...
34 static inline bool Error(std::string *E, const std::string &Message) {
39 // ToStr - Simple wrapper function to convert a type to a string.
40 static std::string ToStr(const Type *Ty, const Module *M) {
41 std::ostringstream OS;
42 WriteTypeSymbolic(OS, Ty, M);
47 // Function: ResolveTypes()
50 // Attempt to link the two specified types together.
53 // DestTy - The type to which we wish to resolve.
54 // SrcTy - The original type which we want to resolve.
57 // DestST - The symbol table in which the new type should be placed.
60 // true - There is an error and the types cannot yet be linked.
63 static bool ResolveTypes(const Type *DestTy, const Type *SrcTy) {
64 if (DestTy == SrcTy) return false; // If already equal, noop
65 assert(DestTy && SrcTy && "Can't handle null types");
67 if (const OpaqueType *OT = dyn_cast<OpaqueType>(DestTy)) {
68 // Type _is_ in module, just opaque...
69 const_cast<OpaqueType*>(OT)->refineAbstractTypeTo(SrcTy);
70 } else if (const OpaqueType *OT = dyn_cast<OpaqueType>(SrcTy)) {
71 const_cast<OpaqueType*>(OT)->refineAbstractTypeTo(DestTy);
73 return true; // Cannot link types... not-equal and neither is opaque.
78 static const FunctionType *getFT(const PATypeHolder &TH) {
79 return cast<FunctionType>(TH.get());
81 static const StructType *getST(const PATypeHolder &TH) {
82 return cast<StructType>(TH.get());
85 // RecursiveResolveTypes - This is just like ResolveTypes, except that it
86 // recurses down into derived types, merging the used types if the parent types
88 static bool RecursiveResolveTypesI(const PATypeHolder &DestTy,
89 const PATypeHolder &SrcTy,
90 std::vector<std::pair<PATypeHolder, PATypeHolder> > &Pointers) {
91 const Type *SrcTyT = SrcTy.get();
92 const Type *DestTyT = DestTy.get();
93 if (DestTyT == SrcTyT) return false; // If already equal, noop
95 // If we found our opaque type, resolve it now!
96 if (isa<OpaqueType>(DestTyT) || isa<OpaqueType>(SrcTyT))
97 return ResolveTypes(DestTyT, SrcTyT);
99 // Two types cannot be resolved together if they are of different primitive
100 // type. For example, we cannot resolve an int to a float.
101 if (DestTyT->getTypeID() != SrcTyT->getTypeID()) return true;
103 // Otherwise, resolve the used type used by this derived type...
104 switch (DestTyT->getTypeID()) {
107 case Type::FunctionTyID: {
108 if (cast<FunctionType>(DestTyT)->isVarArg() !=
109 cast<FunctionType>(SrcTyT)->isVarArg() ||
110 cast<FunctionType>(DestTyT)->getNumContainedTypes() !=
111 cast<FunctionType>(SrcTyT)->getNumContainedTypes())
113 for (unsigned i = 0, e = getFT(DestTy)->getNumContainedTypes(); i != e; ++i)
114 if (RecursiveResolveTypesI(getFT(DestTy)->getContainedType(i),
115 getFT(SrcTy)->getContainedType(i), Pointers))
119 case Type::StructTyID: {
120 if (getST(DestTy)->getNumContainedTypes() !=
121 getST(SrcTy)->getNumContainedTypes())
123 for (unsigned i = 0, e = getST(DestTy)->getNumContainedTypes(); i != e; ++i)
124 if (RecursiveResolveTypesI(getST(DestTy)->getContainedType(i),
125 getST(SrcTy)->getContainedType(i), Pointers))
129 case Type::ArrayTyID: {
130 const ArrayType *DAT = cast<ArrayType>(DestTy.get());
131 const ArrayType *SAT = cast<ArrayType>(SrcTy.get());
132 if (DAT->getNumElements() != SAT->getNumElements()) return true;
133 return RecursiveResolveTypesI(DAT->getElementType(), SAT->getElementType(),
136 case Type::VectorTyID: {
137 const VectorType *DVT = cast<VectorType>(DestTy.get());
138 const VectorType *SVT = cast<VectorType>(SrcTy.get());
139 if (DVT->getNumElements() != SVT->getNumElements()) return true;
140 return RecursiveResolveTypesI(DVT->getElementType(), SVT->getElementType(),
143 case Type::PointerTyID: {
144 // If this is a pointer type, check to see if we have already seen it. If
145 // so, we are in a recursive branch. Cut off the search now. We cannot use
146 // an associative container for this search, because the type pointers (keys
147 // in the container) change whenever types get resolved...
148 for (unsigned i = 0, e = Pointers.size(); i != e; ++i)
149 if (Pointers[i].first == DestTy)
150 return Pointers[i].second != SrcTy;
152 // Otherwise, add the current pointers to the vector to stop recursion on
154 Pointers.push_back(std::make_pair(DestTyT, SrcTyT));
156 RecursiveResolveTypesI(cast<PointerType>(DestTy.get())->getElementType(),
157 cast<PointerType>(SrcTy.get())->getElementType(),
164 static bool RecursiveResolveTypes(const PATypeHolder &DestTy,
165 const PATypeHolder &SrcTy) {
166 std::vector<std::pair<PATypeHolder, PATypeHolder> > PointerTypes;
167 return RecursiveResolveTypesI(DestTy, SrcTy, PointerTypes);
171 // LinkTypes - Go through the symbol table of the Src module and see if any
172 // types are named in the src module that are not named in the Dst module.
173 // Make sure there are no type name conflicts.
174 static bool LinkTypes(Module *Dest, const Module *Src, std::string *Err) {
175 TypeSymbolTable *DestST = &Dest->getTypeSymbolTable();
176 const TypeSymbolTable *SrcST = &Src->getTypeSymbolTable();
178 // Look for a type plane for Type's...
179 TypeSymbolTable::const_iterator TI = SrcST->begin();
180 TypeSymbolTable::const_iterator TE = SrcST->end();
181 if (TI == TE) return false; // No named types, do nothing.
183 // Some types cannot be resolved immediately because they depend on other
184 // types being resolved to each other first. This contains a list of types we
185 // are waiting to recheck.
186 std::vector<std::string> DelayedTypesToResolve;
188 for ( ; TI != TE; ++TI ) {
189 const std::string &Name = TI->first;
190 const Type *RHS = TI->second;
192 // Check to see if this type name is already in the dest module.
193 Type *Entry = DestST->lookup(Name);
195 // If the name is just in the source module, bring it over to the dest.
198 DestST->insert(Name, const_cast<Type*>(RHS));
199 } else if (ResolveTypes(Entry, RHS)) {
200 // They look different, save the types 'till later to resolve.
201 DelayedTypesToResolve.push_back(Name);
205 // Iteratively resolve types while we can...
206 while (!DelayedTypesToResolve.empty()) {
207 // Loop over all of the types, attempting to resolve them if possible...
208 unsigned OldSize = DelayedTypesToResolve.size();
210 // Try direct resolution by name...
211 for (unsigned i = 0; i != DelayedTypesToResolve.size(); ++i) {
212 const std::string &Name = DelayedTypesToResolve[i];
213 Type *T1 = SrcST->lookup(Name);
214 Type *T2 = DestST->lookup(Name);
215 if (!ResolveTypes(T2, T1)) {
216 // We are making progress!
217 DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i);
222 // Did we not eliminate any types?
223 if (DelayedTypesToResolve.size() == OldSize) {
224 // Attempt to resolve subelements of types. This allows us to merge these
225 // two types: { int* } and { opaque* }
226 for (unsigned i = 0, e = DelayedTypesToResolve.size(); i != e; ++i) {
227 const std::string &Name = DelayedTypesToResolve[i];
228 PATypeHolder T1(SrcST->lookup(Name));
229 PATypeHolder T2(DestST->lookup(Name));
231 if (!RecursiveResolveTypes(T2, T1)) {
232 // We are making progress!
233 DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i);
235 // Go back to the main loop, perhaps we can resolve directly by name
241 // If we STILL cannot resolve the types, then there is something wrong.
242 if (DelayedTypesToResolve.size() == OldSize) {
243 // Remove the symbol name from the destination.
244 DelayedTypesToResolve.pop_back();
253 static void PrintMap(const std::map<const Value*, Value*> &M) {
254 for (std::map<const Value*, Value*>::const_iterator I = M.begin(), E =M.end();
256 cerr << " Fr: " << (void*)I->first << " ";
258 cerr << " To: " << (void*)I->second << " ";
265 // RemapOperand - Use ValueMap to convert constants from one module to another.
266 static Value *RemapOperand(const Value *In,
267 std::map<const Value*, Value*> &ValueMap) {
268 std::map<const Value*,Value*>::const_iterator I = ValueMap.find(In);
269 if (I != ValueMap.end())
272 // Check to see if it's a constant that we are interested in transforming.
274 if (const Constant *CPV = dyn_cast<Constant>(In)) {
275 if ((!isa<DerivedType>(CPV->getType()) && !isa<ConstantExpr>(CPV)) ||
276 isa<ConstantInt>(CPV) || isa<ConstantAggregateZero>(CPV))
277 return const_cast<Constant*>(CPV); // Simple constants stay identical.
279 if (const ConstantArray *CPA = dyn_cast<ConstantArray>(CPV)) {
280 std::vector<Constant*> Operands(CPA->getNumOperands());
281 for (unsigned i = 0, e = CPA->getNumOperands(); i != e; ++i)
282 Operands[i] =cast<Constant>(RemapOperand(CPA->getOperand(i), ValueMap));
283 Result = ConstantArray::get(cast<ArrayType>(CPA->getType()), Operands);
284 } else if (const ConstantStruct *CPS = dyn_cast<ConstantStruct>(CPV)) {
285 std::vector<Constant*> Operands(CPS->getNumOperands());
286 for (unsigned i = 0, e = CPS->getNumOperands(); i != e; ++i)
287 Operands[i] =cast<Constant>(RemapOperand(CPS->getOperand(i), ValueMap));
288 Result = ConstantStruct::get(cast<StructType>(CPS->getType()), Operands);
289 } else if (isa<ConstantPointerNull>(CPV) || isa<UndefValue>(CPV)) {
290 Result = const_cast<Constant*>(CPV);
291 } else if (const ConstantVector *CP = dyn_cast<ConstantVector>(CPV)) {
292 std::vector<Constant*> Operands(CP->getNumOperands());
293 for (unsigned i = 0, e = CP->getNumOperands(); i != e; ++i)
294 Operands[i] = cast<Constant>(RemapOperand(CP->getOperand(i), ValueMap));
295 Result = ConstantVector::get(Operands);
296 } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CPV)) {
297 std::vector<Constant*> Ops;
298 for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i)
299 Ops.push_back(cast<Constant>(RemapOperand(CE->getOperand(i),ValueMap)));
300 Result = CE->getWithOperands(Ops);
301 } else if (isa<GlobalValue>(CPV)) {
302 assert(0 && "Unmapped global?");
304 assert(0 && "Unknown type of derived type constant value!");
306 } else if (isa<InlineAsm>(In)) {
307 Result = const_cast<Value*>(In);
310 // Cache the mapping in our local map structure
312 ValueMap[In] = Result;
317 cerr << "LinkModules ValueMap: \n";
320 cerr << "Couldn't remap value: " << (void*)In << " " << *In << "\n";
321 assert(0 && "Couldn't remap value!");
325 /// ForceRenaming - The LLVM SymbolTable class autorenames globals that conflict
326 /// in the symbol table. This is good for all clients except for us. Go
327 /// through the trouble to force this back.
328 static void ForceRenaming(GlobalValue *GV, const std::string &Name) {
329 assert(GV->getName() != Name && "Can't force rename to self");
330 ValueSymbolTable &ST = GV->getParent()->getValueSymbolTable();
332 // If there is a conflict, rename the conflict.
333 if (GlobalValue *ConflictGV = cast_or_null<GlobalValue>(ST.lookup(Name))) {
334 assert(ConflictGV->hasInternalLinkage() &&
335 "Not conflicting with a static global, should link instead!");
336 GV->takeName(ConflictGV);
337 ConflictGV->setName(Name); // This will cause ConflictGV to get renamed
338 assert(ConflictGV->getName() != Name && "ForceRenaming didn't work");
340 GV->setName(Name); // Force the name back
344 /// CopyGVAttributes - copy additional attributes (those not needed to construct
345 /// a GlobalValue) from the SrcGV to the DestGV.
346 static void CopyGVAttributes(GlobalValue *DestGV, const GlobalValue *SrcGV) {
347 // Use the maximum alignment, rather than just copying the alignment of SrcGV.
348 unsigned Alignment = std::max(DestGV->getAlignment(), SrcGV->getAlignment());
349 DestGV->copyAttributesFrom(SrcGV);
350 DestGV->setAlignment(Alignment);
353 /// GetLinkageResult - This analyzes the two global values and determines what
354 /// the result will look like in the destination module. In particular, it
355 /// computes the resultant linkage type, computes whether the global in the
356 /// source should be copied over to the destination (replacing the existing
357 /// one), and computes whether this linkage is an error or not. It also performs
358 /// visibility checks: we cannot link together two symbols with different
360 static bool GetLinkageResult(GlobalValue *Dest, const GlobalValue *Src,
361 GlobalValue::LinkageTypes <, bool &LinkFromSrc,
363 assert((!Dest || !Src->hasInternalLinkage()) &&
364 "If Src has internal linkage, Dest shouldn't be set!");
366 // Linking something to nothing.
368 LT = Src->getLinkage();
369 } else if (Src->isDeclaration()) {
370 // If Src is external or if both Src & Dest are external.. Just link the
371 // external globals, we aren't adding anything.
372 if (Src->hasDLLImportLinkage()) {
373 // If one of GVs has DLLImport linkage, result should be dllimport'ed.
374 if (Dest->isDeclaration()) {
376 LT = Src->getLinkage();
378 } else if (Dest->hasExternalWeakLinkage()) {
379 //If the Dest is weak, use the source linkage
381 LT = Src->getLinkage();
384 LT = Dest->getLinkage();
386 } else if (Dest->isDeclaration() && !Dest->hasDLLImportLinkage()) {
387 // If Dest is external but Src is not:
389 LT = Src->getLinkage();
390 } else if (Src->hasAppendingLinkage() || Dest->hasAppendingLinkage()) {
391 if (Src->getLinkage() != Dest->getLinkage())
392 return Error(Err, "Linking globals named '" + Src->getName() +
393 "': can only link appending global with another appending global!");
394 LinkFromSrc = true; // Special cased.
395 LT = Src->getLinkage();
396 } else if (Src->hasWeakLinkage() || Src->hasLinkOnceLinkage() ||
397 Src->hasCommonLinkage()) {
398 // At this point we know that Dest has LinkOnce, External*, Weak, Common,
400 if ((Dest->hasLinkOnceLinkage() &&
401 (Src->hasWeakLinkage() || Src->hasCommonLinkage())) ||
402 Dest->hasExternalWeakLinkage()) {
404 LT = Src->getLinkage();
407 LT = Dest->getLinkage();
409 } else if (Dest->hasWeakLinkage() || Dest->hasLinkOnceLinkage() ||
410 Dest->hasCommonLinkage()) {
411 // At this point we know that Src has External* or DLL* linkage.
412 if (Src->hasExternalWeakLinkage()) {
414 LT = Dest->getLinkage();
417 LT = GlobalValue::ExternalLinkage;
420 assert((Dest->hasExternalLinkage() ||
421 Dest->hasDLLImportLinkage() ||
422 Dest->hasDLLExportLinkage() ||
423 Dest->hasExternalWeakLinkage()) &&
424 (Src->hasExternalLinkage() ||
425 Src->hasDLLImportLinkage() ||
426 Src->hasDLLExportLinkage() ||
427 Src->hasExternalWeakLinkage()) &&
428 "Unexpected linkage type!");
429 return Error(Err, "Linking globals named '" + Src->getName() +
430 "': symbol multiply defined!");
434 if (Dest && Src->getVisibility() != Dest->getVisibility())
435 if (!Src->isDeclaration() && !Dest->isDeclaration())
436 return Error(Err, "Linking globals named '" + Src->getName() +
437 "': symbols have different visibilities!");
441 // LinkGlobals - Loop through the global variables in the src module and merge
442 // them into the dest module.
443 static bool LinkGlobals(Module *Dest, const Module *Src,
444 std::map<const Value*, Value*> &ValueMap,
445 std::multimap<std::string, GlobalVariable *> &AppendingVars,
447 // Loop over all of the globals in the src module, mapping them over as we go
448 for (Module::const_global_iterator I = Src->global_begin(), E = Src->global_end();
450 const GlobalVariable *SGV = I;
451 GlobalValue *DGV = 0;
453 // Check to see if may have to link the global with the global
454 if (SGV->hasName() && !SGV->hasInternalLinkage()) {
455 DGV = Dest->getGlobalVariable(SGV->getName());
456 if (DGV && DGV->getType() != SGV->getType())
457 // If types don't agree due to opaque types, try to resolve them.
458 RecursiveResolveTypes(SGV->getType(), DGV->getType());
461 // Check to see if may have to link the global with the alias
462 if (!DGV && SGV->hasName() && !SGV->hasInternalLinkage()) {
463 DGV = Dest->getNamedAlias(SGV->getName());
464 if (DGV && DGV->getType() != SGV->getType())
465 // If types don't agree due to opaque types, try to resolve them.
466 RecursiveResolveTypes(SGV->getType(), DGV->getType());
469 if (DGV && DGV->hasInternalLinkage())
472 assert((SGV->hasInitializer() || SGV->hasExternalWeakLinkage() ||
473 SGV->hasExternalLinkage() || SGV->hasDLLImportLinkage()) &&
474 "Global must either be external or have an initializer!");
476 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage;
477 bool LinkFromSrc = false;
478 if (GetLinkageResult(DGV, SGV, NewLinkage, LinkFromSrc, Err))
482 // No linking to be performed, simply create an identical version of the
483 // symbol over in the dest module... the initializer will be filled in
484 // later by LinkGlobalInits...
485 GlobalVariable *NewDGV =
486 new GlobalVariable(SGV->getType()->getElementType(),
487 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
488 SGV->getName(), Dest);
489 // Propagate alignment, visibility and section info.
490 CopyGVAttributes(NewDGV, SGV);
492 // If the LLVM runtime renamed the global, but it is an externally visible
493 // symbol, DGV must be an existing global with internal linkage. Rename
495 if (NewDGV->getName() != SGV->getName() && !NewDGV->hasInternalLinkage())
496 ForceRenaming(NewDGV, SGV->getName());
498 // Make sure to remember this mapping...
499 ValueMap[SGV] = NewDGV;
501 if (SGV->hasAppendingLinkage())
502 // Keep track that this is an appending variable...
503 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV));
504 } else if (DGV->hasAppendingLinkage()) {
505 // No linking is performed yet. Just insert a new copy of the global, and
506 // keep track of the fact that it is an appending variable in the
507 // AppendingVars map. The name is cleared out so that no linkage is
509 GlobalVariable *NewDGV =
510 new GlobalVariable(SGV->getType()->getElementType(),
511 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
514 // Set alignment allowing CopyGVAttributes merge it with alignment of SGV.
515 NewDGV->setAlignment(DGV->getAlignment());
516 // Propagate alignment, section and visibility info.
517 CopyGVAttributes(NewDGV, SGV);
519 // Make sure to remember this mapping...
520 ValueMap[SGV] = NewDGV;
522 // Keep track that this is an appending variable...
523 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV));
524 } else if (GlobalAlias *DGA = dyn_cast<GlobalAlias>(DGV)) {
525 // SGV is global, but DGV is alias. The only valid mapping is when SGV is
526 // external declaration, which is effectively a no-op. Also make sure
527 // linkage calculation was correct.
528 if (SGV->isDeclaration() && !LinkFromSrc) {
529 // Make sure to remember this mapping...
532 return Error(Err, "Global-Alias Collision on '" + SGV->getName() +
533 "': symbol multiple defined");
534 } else if (GlobalVariable *DGVar = dyn_cast<GlobalVariable>(DGV)) {
535 // Otherwise, perform the global-global mapping as instructed by
538 // Propagate alignment, section, and visibility info.
539 CopyGVAttributes(DGVar, SGV);
541 // If the types don't match, and if we are to link from the source, nuke
542 // DGV and create a new one of the appropriate type.
543 if (SGV->getType() != DGVar->getType()) {
544 GlobalVariable *NewDGV =
545 new GlobalVariable(SGV->getType()->getElementType(),
546 DGVar->isConstant(), DGVar->getLinkage(),
547 /*init*/0, DGVar->getName(), Dest);
548 CopyGVAttributes(NewDGV, DGVar);
549 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDGV,
551 // DGVar will conflict with NewDGV because they both had the same
552 // name. We must erase this now so ForceRenaming doesn't assert
553 // because DGV might not have internal linkage.
554 DGVar->eraseFromParent();
556 // If the symbol table renamed the global, but it is an externally
557 // visible symbol, DGV must be an existing global with internal
558 // linkage. Rename it.
559 if (NewDGV->getName() != SGV->getName() &&
560 !NewDGV->hasInternalLinkage())
561 ForceRenaming(NewDGV, SGV->getName());
566 // Inherit const as appropriate
567 DGVar->setConstant(SGV->isConstant());
569 // Set initializer to zero, so we can link the stuff later
570 DGVar->setInitializer(0);
572 // Special case for const propagation
573 if (DGVar->isDeclaration() && SGV->isConstant() && !DGVar->isConstant())
574 DGVar->setConstant(true);
577 // Set calculated linkage
578 DGVar->setLinkage(NewLinkage);
580 // Make sure to remember this mapping...
581 ValueMap[SGV] = ConstantExpr::getBitCast(DGVar, SGV->getType());
587 static GlobalValue::LinkageTypes
588 CalculateAliasLinkage(const GlobalValue *SGV, const GlobalValue *DGV) {
589 if (SGV->hasExternalLinkage() || DGV->hasExternalLinkage())
590 return GlobalValue::ExternalLinkage;
591 else if (SGV->hasWeakLinkage() || DGV->hasWeakLinkage())
592 return GlobalValue::WeakLinkage;
594 assert(SGV->hasInternalLinkage() && DGV->hasInternalLinkage() &&
595 "Unexpected linkage type");
596 return GlobalValue::InternalLinkage;
600 // LinkAlias - Loop through the alias in the src module and link them into the
601 // dest module. We're assuming, that all functions/global variables were already
603 static bool LinkAlias(Module *Dest, const Module *Src,
604 std::map<const Value*, Value*> &ValueMap,
606 // Loop over all alias in the src module
607 for (Module::const_alias_iterator I = Src->alias_begin(),
608 E = Src->alias_end(); I != E; ++I) {
609 const GlobalAlias *SGA = I;
610 const GlobalValue *SAliasee = SGA->getAliasedGlobal();
611 GlobalAlias *NewGA = NULL;
613 // Globals were already linked, thus we can just query ValueMap for variant
614 // of SAliasee in Dest.
615 std::map<const Value*,Value*>::const_iterator VMI = ValueMap.find(SAliasee);
616 assert(VMI != ValueMap.end() && "Aliasee not linked");
617 GlobalValue* DAliasee = cast<GlobalValue>(VMI->second);
618 GlobalValue* DGV = NULL;
620 // Try to find something 'similar' to SGA in destination module.
621 if (!DGV && !SGA->hasInternalLinkage()) {
622 DGV = Dest->getNamedAlias(SGA->getName());
624 // If types don't agree due to opaque types, try to resolve them.
625 if (DGV && DGV->getType() != SGA->getType())
626 if (RecursiveResolveTypes(SGA->getType(), DGV->getType()))
627 return Error(Err, "Alias Collision on '" + SGA->getName()+
628 "': aliases have different types");
631 if (!DGV && !SGA->hasInternalLinkage()) {
632 DGV = Dest->getGlobalVariable(SGA->getName());
634 // If types don't agree due to opaque types, try to resolve them.
635 if (DGV && DGV->getType() != SGA->getType())
636 if (RecursiveResolveTypes(SGA->getType(), DGV->getType()))
637 return Error(Err, "Alias Collision on '" + SGA->getName()+
638 "': aliases have different types");
641 if (!DGV && !SGA->hasInternalLinkage()) {
642 DGV = Dest->getFunction(SGA->getName());
644 // If types don't agree due to opaque types, try to resolve them.
645 if (DGV && DGV->getType() != SGA->getType())
646 if (RecursiveResolveTypes(SGA->getType(), DGV->getType()))
647 return Error(Err, "Alias Collision on '" + SGA->getName()+
648 "': aliases have different types");
651 // No linking to be performed on internal stuff.
652 if (DGV && DGV->hasInternalLinkage())
655 if (GlobalAlias *DGA = dyn_cast_or_null<GlobalAlias>(DGV)) {
656 // Types are known to be the same, check whether aliasees equal. As
657 // globals are already linked we just need query ValueMap to find the
659 if (DAliasee == DGA->getAliasedGlobal()) {
660 // This is just two copies of the same alias. Propagate linkage, if
662 DGA->setLinkage(CalculateAliasLinkage(SGA, DGA));
665 // Proceed to 'common' steps
667 return Error(Err, "Alias Collision on '" + SGA->getName()+
668 "': aliases have different aliasees");
669 } else if (GlobalVariable *DGVar = dyn_cast_or_null<GlobalVariable>(DGV)) {
670 // The only allowed way is to link alias with external declaration.
671 if (DGVar->isDeclaration()) {
672 // But only if aliasee is global too...
673 if (!isa<GlobalVariable>(DAliasee))
674 return Error(Err, "Global-Alias Collision on '" + SGA->getName() +
675 "': aliasee is not global variable");
677 NewGA = new GlobalAlias(SGA->getType(), SGA->getLinkage(),
678 SGA->getName(), DAliasee, Dest);
679 CopyGVAttributes(NewGA, SGA);
681 // Any uses of DGV need to change to NewGA, with cast, if needed.
682 if (SGA->getType() != DGVar->getType())
683 DGVar->replaceAllUsesWith(ConstantExpr::getBitCast(NewGA,
686 DGVar->replaceAllUsesWith(NewGA);
688 // DGVar will conflict with NewGA because they both had the same
689 // name. We must erase this now so ForceRenaming doesn't assert
690 // because DGV might not have internal linkage.
691 DGVar->eraseFromParent();
693 // Proceed to 'common' steps
695 return Error(Err, "Global-Alias Collision on '" + SGA->getName() +
696 "': symbol multiple defined");
697 } else if (Function *DF = dyn_cast_or_null<Function>(DGV)) {
698 // The only allowed way is to link alias with external declaration.
699 if (DF->isDeclaration()) {
700 // But only if aliasee is function too...
701 if (!isa<Function>(DAliasee))
702 return Error(Err, "Function-Alias Collision on '" + SGA->getName() +
703 "': aliasee is not function");
705 NewGA = new GlobalAlias(SGA->getType(), SGA->getLinkage(),
706 SGA->getName(), DAliasee, Dest);
707 CopyGVAttributes(NewGA, SGA);
709 // Any uses of DF need to change to NewGA, with cast, if needed.
710 if (SGA->getType() != DF->getType())
711 DF->replaceAllUsesWith(ConstantExpr::getBitCast(NewGA,
714 DF->replaceAllUsesWith(NewGA);
716 // DF will conflict with NewGA because they both had the same
717 // name. We must erase this now so ForceRenaming doesn't assert
718 // because DF might not have internal linkage.
719 DF->eraseFromParent();
721 // Proceed to 'common' steps
723 return Error(Err, "Function-Alias Collision on '" + SGA->getName() +
724 "': symbol multiple defined");
726 // No linking to be performed, simply create an identical version of the
727 // alias over in the dest module...
729 NewGA = new GlobalAlias(SGA->getType(), SGA->getLinkage(),
730 SGA->getName(), DAliasee, Dest);
731 CopyGVAttributes(NewGA, SGA);
733 // Proceed to 'common' steps
736 assert(NewGA && "No alias was created in destination module!");
738 // If the symbol table renamed the alias, but it is an externally visible
739 // symbol, DGA must be an global value with internal linkage. Rename it.
740 if (NewGA->getName() != SGA->getName() &&
741 !NewGA->hasInternalLinkage())
742 ForceRenaming(NewGA, SGA->getName());
744 // Remember this mapping so uses in the source module get remapped
745 // later by RemapOperand.
746 ValueMap[SGA] = NewGA;
753 // LinkGlobalInits - Update the initializers in the Dest module now that all
754 // globals that may be referenced are in Dest.
755 static bool LinkGlobalInits(Module *Dest, const Module *Src,
756 std::map<const Value*, Value*> &ValueMap,
759 // Loop over all of the globals in the src module, mapping them over as we go
760 for (Module::const_global_iterator I = Src->global_begin(),
761 E = Src->global_end(); I != E; ++I) {
762 const GlobalVariable *SGV = I;
764 if (SGV->hasInitializer()) { // Only process initialized GV's
765 // Figure out what the initializer looks like in the dest module...
767 cast<Constant>(RemapOperand(SGV->getInitializer(), ValueMap));
769 GlobalVariable *DGV =
770 cast<GlobalVariable>(ValueMap[SGV]->stripPointerCasts());
771 if (DGV->hasInitializer()) {
772 if (SGV->hasExternalLinkage()) {
773 if (DGV->getInitializer() != SInit)
774 return Error(Err, "Global Variable Collision on '" + SGV->getName() +
775 "': global variables have different initializers");
776 } else if (DGV->hasLinkOnceLinkage() || DGV->hasWeakLinkage() ||
777 DGV->hasCommonLinkage()) {
778 // Nothing is required, mapped values will take the new global
780 } else if (SGV->hasLinkOnceLinkage() || SGV->hasWeakLinkage() ||
781 SGV->hasCommonLinkage()) {
782 // Nothing is required, mapped values will take the new global
784 } else if (DGV->hasAppendingLinkage()) {
785 assert(0 && "Appending linkage unimplemented!");
787 assert(0 && "Unknown linkage!");
790 // Copy the initializer over now...
791 DGV->setInitializer(SInit);
798 // LinkFunctionProtos - Link the functions together between the two modules,
799 // without doing function bodies... this just adds external function prototypes
800 // to the Dest function...
802 static bool LinkFunctionProtos(Module *Dest, const Module *Src,
803 std::map<const Value*, Value*> &ValueMap,
805 // Loop over all of the functions in the src module, mapping them over
806 for (Module::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) {
807 const Function *SF = I; // SrcFunction
811 // If this function is internal or has no name, it doesn't participate in
813 if (SF->hasName() && !SF->hasInternalLinkage()) {
814 // Check to see if may have to link the function.
815 DF = Dest->getFunction(SF->getName());
816 if (DF && DF->hasInternalLinkage())
820 // If there is no linkage to be performed, just bring over SF without
823 // Function does not already exist, simply insert an function signature
824 // identical to SF into the dest module.
825 Function *NewDF = Function::Create(SF->getFunctionType(),
827 SF->getName(), Dest);
828 CopyGVAttributes(NewDF, SF);
830 // If the LLVM runtime renamed the function, but it is an externally
831 // visible symbol, DF must be an existing function with internal linkage.
833 if (!NewDF->hasInternalLinkage() && NewDF->getName() != SF->getName())
834 ForceRenaming(NewDF, SF->getName());
836 // ... and remember this mapping...
837 ValueMap[SF] = NewDF;
842 // If types don't agree because of opaque, try to resolve them.
843 if (SF->getType() != DF->getType())
844 RecursiveResolveTypes(SF->getType(), DF->getType());
846 // Check visibility, merging if a definition overrides a prototype.
847 if (SF->getVisibility() != DF->getVisibility()) {
848 // If one is a prototype, ignore its visibility. Prototypes are always
849 // overridden by the definition.
850 if (!SF->isDeclaration() && !DF->isDeclaration())
851 return Error(Err, "Linking functions named '" + SF->getName() +
852 "': symbols have different visibilities!");
854 // Otherwise, replace the visibility of DF if DF is a prototype.
855 if (DF->isDeclaration())
856 DF->setVisibility(SF->getVisibility());
859 if (DF->getType() != SF->getType()) {
860 if (DF->isDeclaration() && !SF->isDeclaration()) {
861 // We have a definition of the same name but different type in the
862 // source module. Copy the prototype to the destination and replace
863 // uses of the destination's prototype with the new prototype.
864 Function *NewDF = Function::Create(SF->getFunctionType(),
866 SF->getName(), Dest);
867 CopyGVAttributes(NewDF, SF);
869 // Any uses of DF need to change to NewDF, with cast
870 DF->replaceAllUsesWith(ConstantExpr::getBitCast(NewDF, DF->getType()));
872 // DF will conflict with NewDF because they both had the same. We must
873 // erase this now so ForceRenaming doesn't assert because DF might
874 // not have internal linkage.
875 DF->eraseFromParent();
877 // If the symbol table renamed the function, but it is an externally
878 // visible symbol, DF must be an existing function with internal
879 // linkage. Rename it.
880 if (NewDF->getName() != SF->getName() && !NewDF->hasInternalLinkage())
881 ForceRenaming(NewDF, SF->getName());
883 // Remember this mapping so uses in the source module get remapped
884 // later by RemapOperand.
885 ValueMap[SF] = NewDF;
886 } else if (SF->isDeclaration()) {
887 // We have two functions of the same name but different type and the
888 // source is a declaration while the destination is not. Any use of
889 // the source must be mapped to the destination, with a cast.
890 ValueMap[SF] = ConstantExpr::getBitCast(DF, SF->getType());
892 // We have two functions of the same name but different types and they
893 // are both definitions. This is an error.
894 return Error(Err, "Function '" + DF->getName() + "' defined as both '" +
895 ToStr(SF->getFunctionType(), Src) + "' and '" +
896 ToStr(DF->getFunctionType(), Dest) + "'");
901 if (SF->isDeclaration()) {
902 // If SF is a declaration or if both SF & DF are declarations, just link
903 // the declarations, we aren't adding anything.
904 if (SF->hasDLLImportLinkage()) {
905 if (DF->isDeclaration()) {
907 DF->setLinkage(SF->getLinkage());
915 // If DF is external but SF is not, link the external functions, update
916 // linkage qualifiers.
917 if (DF->isDeclaration() && !DF->hasDLLImportLinkage()) {
918 ValueMap.insert(std::make_pair(SF, DF));
919 DF->setLinkage(SF->getLinkage());
923 // At this point we know that DF has LinkOnce, Weak, or External* linkage.
924 if (SF->hasWeakLinkage() || SF->hasLinkOnceLinkage() ||
925 SF->hasCommonLinkage()) {
928 // Linkonce+Weak = Weak
929 // *+External Weak = *
930 if ((DF->hasLinkOnceLinkage() &&
931 (SF->hasWeakLinkage() || SF->hasCommonLinkage())) ||
932 DF->hasExternalWeakLinkage())
933 DF->setLinkage(SF->getLinkage());
937 if (DF->hasWeakLinkage() || DF->hasLinkOnceLinkage() ||
938 DF->hasCommonLinkage()) {
939 // At this point we know that SF has LinkOnce or External* linkage.
942 // If the source function has stronger linkage than the destination,
943 // its body and linkage should override ours.
944 if (!SF->hasLinkOnceLinkage() && !SF->hasExternalWeakLinkage()) {
945 // Don't inherit linkonce & external weak linkage.
946 DF->setLinkage(SF->getLinkage());
952 if (SF->getLinkage() != DF->getLinkage())
953 return Error(Err, "Functions named '" + SF->getName() +
954 "' have different linkage specifiers!");
956 // The function is defined identically in both modules!
957 if (SF->hasExternalLinkage())
958 return Error(Err, "Function '" +
959 ToStr(SF->getFunctionType(), Src) + "':\"" +
960 SF->getName() + "\" - Function is already defined!");
961 assert(0 && "Unknown linkage configuration found!");
966 // LinkFunctionBody - Copy the source function over into the dest function and
967 // fix up references to values. At this point we know that Dest is an external
968 // function, and that Src is not.
969 static bool LinkFunctionBody(Function *Dest, Function *Src,
970 std::map<const Value*, Value*> &ValueMap,
972 assert(Src && Dest && Dest->isDeclaration() && !Src->isDeclaration());
974 // Go through and convert function arguments over, remembering the mapping.
975 Function::arg_iterator DI = Dest->arg_begin();
976 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end();
978 DI->setName(I->getName()); // Copy the name information over...
980 // Add a mapping to our local map
984 // Splice the body of the source function into the dest function.
985 Dest->getBasicBlockList().splice(Dest->end(), Src->getBasicBlockList());
987 // At this point, all of the instructions and values of the function are now
988 // copied over. The only problem is that they are still referencing values in
989 // the Source function as operands. Loop through all of the operands of the
990 // functions and patch them up to point to the local versions...
992 for (Function::iterator BB = Dest->begin(), BE = Dest->end(); BB != BE; ++BB)
993 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
994 for (Instruction::op_iterator OI = I->op_begin(), OE = I->op_end();
996 if (!isa<Instruction>(*OI) && !isa<BasicBlock>(*OI))
997 *OI = RemapOperand(*OI, ValueMap);
999 // There is no need to map the arguments anymore.
1000 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end();
1008 // LinkFunctionBodies - Link in the function bodies that are defined in the
1009 // source module into the DestModule. This consists basically of copying the
1010 // function over and fixing up references to values.
1011 static bool LinkFunctionBodies(Module *Dest, Module *Src,
1012 std::map<const Value*, Value*> &ValueMap,
1015 // Loop over all of the functions in the src module, mapping them over as we
1017 for (Module::iterator SF = Src->begin(), E = Src->end(); SF != E; ++SF) {
1018 if (!SF->isDeclaration()) { // No body if function is external
1019 Function *DF = cast<Function>(ValueMap[SF]); // Destination function
1021 // DF not external SF external?
1022 if (DF->isDeclaration())
1023 // Only provide the function body if there isn't one already.
1024 if (LinkFunctionBody(DF, SF, ValueMap, Err))
1031 // LinkAppendingVars - If there were any appending global variables, link them
1032 // together now. Return true on error.
1033 static bool LinkAppendingVars(Module *M,
1034 std::multimap<std::string, GlobalVariable *> &AppendingVars,
1035 std::string *ErrorMsg) {
1036 if (AppendingVars.empty()) return false; // Nothing to do.
1038 // Loop over the multimap of appending vars, processing any variables with the
1039 // same name, forming a new appending global variable with both of the
1040 // initializers merged together, then rewrite references to the old variables
1042 std::vector<Constant*> Inits;
1043 while (AppendingVars.size() > 1) {
1044 // Get the first two elements in the map...
1045 std::multimap<std::string,
1046 GlobalVariable*>::iterator Second = AppendingVars.begin(), First=Second++;
1048 // If the first two elements are for different names, there is no pair...
1049 // Otherwise there is a pair, so link them together...
1050 if (First->first == Second->first) {
1051 GlobalVariable *G1 = First->second, *G2 = Second->second;
1052 const ArrayType *T1 = cast<ArrayType>(G1->getType()->getElementType());
1053 const ArrayType *T2 = cast<ArrayType>(G2->getType()->getElementType());
1055 // Check to see that they two arrays agree on type...
1056 if (T1->getElementType() != T2->getElementType())
1057 return Error(ErrorMsg,
1058 "Appending variables with different element types need to be linked!");
1059 if (G1->isConstant() != G2->isConstant())
1060 return Error(ErrorMsg,
1061 "Appending variables linked with different const'ness!");
1063 if (G1->getAlignment() != G2->getAlignment())
1064 return Error(ErrorMsg,
1065 "Appending variables with different alignment need to be linked!");
1067 if (G1->getVisibility() != G2->getVisibility())
1068 return Error(ErrorMsg,
1069 "Appending variables with different visibility need to be linked!");
1071 if (G1->getSection() != G2->getSection())
1072 return Error(ErrorMsg,
1073 "Appending variables with different section name need to be linked!");
1075 unsigned NewSize = T1->getNumElements() + T2->getNumElements();
1076 ArrayType *NewType = ArrayType::get(T1->getElementType(), NewSize);
1078 G1->setName(""); // Clear G1's name in case of a conflict!
1080 // Create the new global variable...
1081 GlobalVariable *NG =
1082 new GlobalVariable(NewType, G1->isConstant(), G1->getLinkage(),
1083 /*init*/0, First->first, M, G1->isThreadLocal());
1085 // Propagate alignment, visibility and section info.
1086 CopyGVAttributes(NG, G1);
1088 // Merge the initializer...
1089 Inits.reserve(NewSize);
1090 if (ConstantArray *I = dyn_cast<ConstantArray>(G1->getInitializer())) {
1091 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i)
1092 Inits.push_back(I->getOperand(i));
1094 assert(isa<ConstantAggregateZero>(G1->getInitializer()));
1095 Constant *CV = Constant::getNullValue(T1->getElementType());
1096 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i)
1097 Inits.push_back(CV);
1099 if (ConstantArray *I = dyn_cast<ConstantArray>(G2->getInitializer())) {
1100 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i)
1101 Inits.push_back(I->getOperand(i));
1103 assert(isa<ConstantAggregateZero>(G2->getInitializer()));
1104 Constant *CV = Constant::getNullValue(T2->getElementType());
1105 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i)
1106 Inits.push_back(CV);
1108 NG->setInitializer(ConstantArray::get(NewType, Inits));
1111 // Replace any uses of the two global variables with uses of the new
1114 // FIXME: This should rewrite simple/straight-forward uses such as
1115 // getelementptr instructions to not use the Cast!
1116 G1->replaceAllUsesWith(ConstantExpr::getBitCast(NG, G1->getType()));
1117 G2->replaceAllUsesWith(ConstantExpr::getBitCast(NG, G2->getType()));
1119 // Remove the two globals from the module now...
1120 M->getGlobalList().erase(G1);
1121 M->getGlobalList().erase(G2);
1123 // Put the new global into the AppendingVars map so that we can handle
1124 // linking of more than two vars...
1125 Second->second = NG;
1127 AppendingVars.erase(First);
1133 static bool ResolveAliases(Module *Dest) {
1134 for (Module::alias_iterator I = Dest->alias_begin(), E = Dest->alias_end();
1136 if (const GlobalValue *GV = I->resolveAliasedGlobal())
1137 if (!GV->isDeclaration())
1138 I->replaceAllUsesWith(const_cast<GlobalValue*>(GV));
1143 // LinkModules - This function links two modules together, with the resulting
1144 // left module modified to be the composite of the two input modules. If an
1145 // error occurs, true is returned and ErrorMsg (if not null) is set to indicate
1146 // the problem. Upon failure, the Dest module could be in a modified state, and
1147 // shouldn't be relied on to be consistent.
1149 Linker::LinkModules(Module *Dest, Module *Src, std::string *ErrorMsg) {
1150 assert(Dest != 0 && "Invalid Destination module");
1151 assert(Src != 0 && "Invalid Source Module");
1153 if (Dest->getDataLayout().empty()) {
1154 if (!Src->getDataLayout().empty()) {
1155 Dest->setDataLayout(Src->getDataLayout());
1157 std::string DataLayout;
1159 if (Dest->getEndianness() == Module::AnyEndianness) {
1160 if (Src->getEndianness() == Module::BigEndian)
1161 DataLayout.append("E");
1162 else if (Src->getEndianness() == Module::LittleEndian)
1163 DataLayout.append("e");
1166 if (Dest->getPointerSize() == Module::AnyPointerSize) {
1167 if (Src->getPointerSize() == Module::Pointer64)
1168 DataLayout.append(DataLayout.length() == 0 ? "p:64:64" : "-p:64:64");
1169 else if (Src->getPointerSize() == Module::Pointer32)
1170 DataLayout.append(DataLayout.length() == 0 ? "p:32:32" : "-p:32:32");
1172 Dest->setDataLayout(DataLayout);
1176 // Copy the target triple from the source to dest if the dest's is empty.
1177 if (Dest->getTargetTriple().empty() && !Src->getTargetTriple().empty())
1178 Dest->setTargetTriple(Src->getTargetTriple());
1180 if (!Src->getDataLayout().empty() && !Dest->getDataLayout().empty() &&
1181 Src->getDataLayout() != Dest->getDataLayout())
1182 cerr << "WARNING: Linking two modules of different data layouts!\n";
1183 if (!Src->getTargetTriple().empty() &&
1184 Dest->getTargetTriple() != Src->getTargetTriple())
1185 cerr << "WARNING: Linking two modules of different target triples!\n";
1187 // Append the module inline asm string.
1188 if (!Src->getModuleInlineAsm().empty()) {
1189 if (Dest->getModuleInlineAsm().empty())
1190 Dest->setModuleInlineAsm(Src->getModuleInlineAsm());
1192 Dest->setModuleInlineAsm(Dest->getModuleInlineAsm()+"\n"+
1193 Src->getModuleInlineAsm());
1196 // Update the destination module's dependent libraries list with the libraries
1197 // from the source module. There's no opportunity for duplicates here as the
1198 // Module ensures that duplicate insertions are discarded.
1199 for (Module::lib_iterator SI = Src->lib_begin(), SE = Src->lib_end();
1201 Dest->addLibrary(*SI);
1203 // LinkTypes - Go through the symbol table of the Src module and see if any
1204 // types are named in the src module that are not named in the Dst module.
1205 // Make sure there are no type name conflicts.
1206 if (LinkTypes(Dest, Src, ErrorMsg))
1209 // ValueMap - Mapping of values from what they used to be in Src, to what they
1211 std::map<const Value*, Value*> ValueMap;
1213 // AppendingVars - Keep track of global variables in the destination module
1214 // with appending linkage. After the module is linked together, they are
1215 // appended and the module is rewritten.
1216 std::multimap<std::string, GlobalVariable *> AppendingVars;
1217 for (Module::global_iterator I = Dest->global_begin(), E = Dest->global_end();
1219 // Add all of the appending globals already in the Dest module to
1221 if (I->hasAppendingLinkage())
1222 AppendingVars.insert(std::make_pair(I->getName(), I));
1225 // Insert all of the globals in src into the Dest module... without linking
1226 // initializers (which could refer to functions not yet mapped over).
1227 if (LinkGlobals(Dest, Src, ValueMap, AppendingVars, ErrorMsg))
1230 // Link the functions together between the two modules, without doing function
1231 // bodies... this just adds external function prototypes to the Dest
1232 // function... We do this so that when we begin processing function bodies,
1233 // all of the global values that may be referenced are available in our
1235 if (LinkFunctionProtos(Dest, Src, ValueMap, ErrorMsg))
1238 // If there were any alias, link them now. We really need to do this now,
1239 // because all of the aliases that may be referenced need to be available in
1241 if (LinkAlias(Dest, Src, ValueMap, ErrorMsg)) return true;
1243 // Update the initializers in the Dest module now that all globals that may
1244 // be referenced are in Dest.
1245 if (LinkGlobalInits(Dest, Src, ValueMap, ErrorMsg)) return true;
1247 // Link in the function bodies that are defined in the source module into the
1248 // DestModule. This consists basically of copying the function over and
1249 // fixing up references to values.
1250 if (LinkFunctionBodies(Dest, Src, ValueMap, ErrorMsg)) return true;
1252 // If there were any appending global variables, link them together now.
1253 if (LinkAppendingVars(Dest, AppendingVars, ErrorMsg)) return true;
1255 // Resolve all uses of aliases with aliasees
1256 if (ResolveAliases(Dest)) return true;
1258 // If the source library's module id is in the dependent library list of the
1259 // destination library, remove it since that module is now linked in.
1261 modId.set(Src->getModuleIdentifier());
1262 if (!modId.isEmpty())
1263 Dest->removeLibrary(modId.getBasename());