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 // RecursiveResolveTypes - This is just like ResolveTypes, except that it
79 // recurses down into derived types, merging the used types if the parent types
81 static bool RecursiveResolveTypesI(const PATypeHolder &DestTy,
82 const PATypeHolder &SrcTy,
83 std::vector<std::pair<PATypeHolder, PATypeHolder> > &Pointers) {
84 const Type *SrcTyT = SrcTy.get();
85 const Type *DestTyT = DestTy.get();
86 if (DestTyT == SrcTyT) return false; // If already equal, noop
88 // If we found our opaque type, resolve it now!
89 if (isa<OpaqueType>(DestTyT) || isa<OpaqueType>(SrcTyT))
90 return ResolveTypes(DestTyT, SrcTyT);
92 // Two types cannot be resolved together if they are of different primitive
93 // type. For example, we cannot resolve an int to a float.
94 if (DestTyT->getTypeID() != SrcTyT->getTypeID()) return true;
96 // If neither type is abstract, then they really are just different types.
97 if (!DestTyT->isAbstract() && !SrcTyT->isAbstract())
100 // Otherwise, resolve the used type used by this derived type...
101 switch (DestTyT->getTypeID()) {
104 case Type::FunctionTyID: {
105 const FunctionType *DstFT = cast<FunctionType>(DestTyT);
106 const FunctionType *SrcFT = cast<FunctionType>(SrcTyT);
107 if (DstFT->isVarArg() != SrcFT->isVarArg() ||
108 DstFT->getNumContainedTypes() != SrcFT->getNumContainedTypes())
110 for (unsigned i = 0, e = DstFT->getNumContainedTypes(); i != e; ++i)
111 if (RecursiveResolveTypesI(DstFT->getContainedType(i),
112 SrcFT->getContainedType(i), Pointers))
116 case Type::StructTyID: {
117 const StructType *DstST = cast<StructType>(DestTyT);
118 const StructType *SrcST = cast<StructType>(SrcTyT);
119 if (DstST->getNumContainedTypes() != SrcST->getNumContainedTypes())
121 for (unsigned i = 0, e = DstST->getNumContainedTypes(); i != e; ++i)
122 if (RecursiveResolveTypesI(DstST->getContainedType(i),
123 SrcST->getContainedType(i), Pointers))
127 case Type::ArrayTyID: {
128 const ArrayType *DAT = cast<ArrayType>(DestTy.get());
129 const ArrayType *SAT = cast<ArrayType>(SrcTy.get());
130 if (DAT->getNumElements() != SAT->getNumElements()) return true;
131 return RecursiveResolveTypesI(DAT->getElementType(), SAT->getElementType(),
134 case Type::VectorTyID: {
135 const VectorType *DVT = cast<VectorType>(DestTy.get());
136 const VectorType *SVT = cast<VectorType>(SrcTy.get());
137 if (DVT->getNumElements() != SVT->getNumElements()) return true;
138 return RecursiveResolveTypesI(DVT->getElementType(), SVT->getElementType(),
141 case Type::PointerTyID: {
142 const PointerType *DstPT = cast<PointerType>(DestTy.get());
143 const PointerType *SrcPT = cast<PointerType>(SrcTy.get());
145 if (DstPT->getAddressSpace() != SrcPT->getAddressSpace())
148 // If this is a pointer type, check to see if we have already seen it. If
149 // so, we are in a recursive branch. Cut off the search now. We cannot use
150 // an associative container for this search, because the type pointers (keys
151 // in the container) change whenever types get resolved...
152 for (unsigned i = 0, e = Pointers.size(); i != e; ++i)
153 if (Pointers[i].first == DestTy)
154 return Pointers[i].second != SrcTy;
156 // Otherwise, add the current pointers to the vector to stop recursion on
158 Pointers.push_back(std::make_pair(DestTyT, SrcTyT));
159 return RecursiveResolveTypesI(DstPT->getElementType(),
160 SrcPT->getElementType(), Pointers);
165 static bool RecursiveResolveTypes(const PATypeHolder &DestTy,
166 const PATypeHolder &SrcTy) {
167 std::vector<std::pair<PATypeHolder, PATypeHolder> > PointerTypes;
168 return RecursiveResolveTypesI(DestTy, SrcTy, PointerTypes);
172 // LinkTypes - Go through the symbol table of the Src module and see if any
173 // types are named in the src module that are not named in the Dst module.
174 // Make sure there are no type name conflicts.
175 static bool LinkTypes(Module *Dest, const Module *Src, std::string *Err) {
176 TypeSymbolTable *DestST = &Dest->getTypeSymbolTable();
177 const TypeSymbolTable *SrcST = &Src->getTypeSymbolTable();
179 // Look for a type plane for Type's...
180 TypeSymbolTable::const_iterator TI = SrcST->begin();
181 TypeSymbolTable::const_iterator TE = SrcST->end();
182 if (TI == TE) return false; // No named types, do nothing.
184 // Some types cannot be resolved immediately because they depend on other
185 // types being resolved to each other first. This contains a list of types we
186 // are waiting to recheck.
187 std::vector<std::string> DelayedTypesToResolve;
189 for ( ; TI != TE; ++TI ) {
190 const std::string &Name = TI->first;
191 const Type *RHS = TI->second;
193 // Check to see if this type name is already in the dest module.
194 Type *Entry = DestST->lookup(Name);
196 // If the name is just in the source module, bring it over to the dest.
199 DestST->insert(Name, const_cast<Type*>(RHS));
200 } else if (ResolveTypes(Entry, RHS)) {
201 // They look different, save the types 'till later to resolve.
202 DelayedTypesToResolve.push_back(Name);
206 // Iteratively resolve types while we can...
207 while (!DelayedTypesToResolve.empty()) {
208 // Loop over all of the types, attempting to resolve them if possible...
209 unsigned OldSize = DelayedTypesToResolve.size();
211 // Try direct resolution by name...
212 for (unsigned i = 0; i != DelayedTypesToResolve.size(); ++i) {
213 const std::string &Name = DelayedTypesToResolve[i];
214 Type *T1 = SrcST->lookup(Name);
215 Type *T2 = DestST->lookup(Name);
216 if (!ResolveTypes(T2, T1)) {
217 // We are making progress!
218 DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i);
223 // Did we not eliminate any types?
224 if (DelayedTypesToResolve.size() == OldSize) {
225 // Attempt to resolve subelements of types. This allows us to merge these
226 // two types: { int* } and { opaque* }
227 for (unsigned i = 0, e = DelayedTypesToResolve.size(); i != e; ++i) {
228 const std::string &Name = DelayedTypesToResolve[i];
229 PATypeHolder T1(SrcST->lookup(Name));
230 PATypeHolder T2(DestST->lookup(Name));
232 if (!RecursiveResolveTypes(T2, T1)) {
233 // We are making progress!
234 DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i);
236 // Go back to the main loop, perhaps we can resolve directly by name
242 // If we STILL cannot resolve the types, then there is something wrong.
243 if (DelayedTypesToResolve.size() == OldSize) {
244 // Remove the symbol name from the destination.
245 DelayedTypesToResolve.pop_back();
254 static void PrintMap(const std::map<const Value*, Value*> &M) {
255 for (std::map<const Value*, Value*>::const_iterator I = M.begin(), E =M.end();
257 cerr << " Fr: " << (void*)I->first << " ";
259 cerr << " To: " << (void*)I->second << " ";
266 // RemapOperand - Use ValueMap to convert constants from one module to another.
267 static Value *RemapOperand(const Value *In,
268 std::map<const Value*, Value*> &ValueMap) {
269 std::map<const Value*,Value*>::const_iterator I = ValueMap.find(In);
270 if (I != ValueMap.end())
273 // Check to see if it's a constant that we are interested in transforming.
275 if (const Constant *CPV = dyn_cast<Constant>(In)) {
276 if ((!isa<DerivedType>(CPV->getType()) && !isa<ConstantExpr>(CPV)) ||
277 isa<ConstantInt>(CPV) || isa<ConstantAggregateZero>(CPV))
278 return const_cast<Constant*>(CPV); // Simple constants stay identical.
280 if (const ConstantArray *CPA = dyn_cast<ConstantArray>(CPV)) {
281 std::vector<Constant*> Operands(CPA->getNumOperands());
282 for (unsigned i = 0, e = CPA->getNumOperands(); i != e; ++i)
283 Operands[i] =cast<Constant>(RemapOperand(CPA->getOperand(i), ValueMap));
284 Result = ConstantArray::get(cast<ArrayType>(CPA->getType()), Operands);
285 } else if (const ConstantStruct *CPS = dyn_cast<ConstantStruct>(CPV)) {
286 std::vector<Constant*> Operands(CPS->getNumOperands());
287 for (unsigned i = 0, e = CPS->getNumOperands(); i != e; ++i)
288 Operands[i] =cast<Constant>(RemapOperand(CPS->getOperand(i), ValueMap));
289 Result = ConstantStruct::get(cast<StructType>(CPS->getType()), Operands);
290 } else if (isa<ConstantPointerNull>(CPV) || isa<UndefValue>(CPV)) {
291 Result = const_cast<Constant*>(CPV);
292 } else if (const ConstantVector *CP = dyn_cast<ConstantVector>(CPV)) {
293 std::vector<Constant*> Operands(CP->getNumOperands());
294 for (unsigned i = 0, e = CP->getNumOperands(); i != e; ++i)
295 Operands[i] = cast<Constant>(RemapOperand(CP->getOperand(i), ValueMap));
296 Result = ConstantVector::get(Operands);
297 } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CPV)) {
298 std::vector<Constant*> Ops;
299 for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i)
300 Ops.push_back(cast<Constant>(RemapOperand(CE->getOperand(i),ValueMap)));
301 Result = CE->getWithOperands(Ops);
302 } else if (isa<GlobalValue>(CPV)) {
303 assert(0 && "Unmapped global?");
305 assert(0 && "Unknown type of derived type constant value!");
307 } else if (isa<InlineAsm>(In)) {
308 Result = const_cast<Value*>(In);
311 // Cache the mapping in our local map structure
313 ValueMap[In] = Result;
318 cerr << "LinkModules ValueMap: \n";
321 cerr << "Couldn't remap value: " << (void*)In << " " << *In << "\n";
322 assert(0 && "Couldn't remap value!");
326 /// ForceRenaming - The LLVM SymbolTable class autorenames globals that conflict
327 /// in the symbol table. This is good for all clients except for us. Go
328 /// through the trouble to force this back.
329 static void ForceRenaming(GlobalValue *GV, const std::string &Name) {
330 assert(GV->getName() != Name && "Can't force rename to self");
331 ValueSymbolTable &ST = GV->getParent()->getValueSymbolTable();
333 // If there is a conflict, rename the conflict.
334 if (GlobalValue *ConflictGV = cast_or_null<GlobalValue>(ST.lookup(Name))) {
335 assert(ConflictGV->hasInternalLinkage() &&
336 "Not conflicting with a static global, should link instead!");
337 GV->takeName(ConflictGV);
338 ConflictGV->setName(Name); // This will cause ConflictGV to get renamed
339 assert(ConflictGV->getName() != Name && "ForceRenaming didn't work");
341 GV->setName(Name); // Force the name back
345 /// CopyGVAttributes - copy additional attributes (those not needed to construct
346 /// a GlobalValue) from the SrcGV to the DestGV.
347 static void CopyGVAttributes(GlobalValue *DestGV, const GlobalValue *SrcGV) {
348 // Use the maximum alignment, rather than just copying the alignment of SrcGV.
349 unsigned Alignment = std::max(DestGV->getAlignment(), SrcGV->getAlignment());
350 DestGV->copyAttributesFrom(SrcGV);
351 DestGV->setAlignment(Alignment);
354 /// GetLinkageResult - This analyzes the two global values and determines what
355 /// the result will look like in the destination module. In particular, it
356 /// computes the resultant linkage type, computes whether the global in the
357 /// source should be copied over to the destination (replacing the existing
358 /// one), and computes whether this linkage is an error or not. It also performs
359 /// visibility checks: we cannot link together two symbols with different
361 static bool GetLinkageResult(GlobalValue *Dest, const GlobalValue *Src,
362 GlobalValue::LinkageTypes <, bool &LinkFromSrc,
364 assert((!Dest || !Src->hasInternalLinkage()) &&
365 "If Src has internal linkage, Dest shouldn't be set!");
367 // Linking something to nothing.
369 LT = Src->getLinkage();
370 } else if (Src->isDeclaration()) {
371 // If Src is external or if both Src & Dest are external.. Just link the
372 // external globals, we aren't adding anything.
373 if (Src->hasDLLImportLinkage()) {
374 // If one of GVs has DLLImport linkage, result should be dllimport'ed.
375 if (Dest->isDeclaration()) {
377 LT = Src->getLinkage();
379 } else if (Dest->hasExternalWeakLinkage()) {
380 //If the Dest is weak, use the source linkage
382 LT = Src->getLinkage();
385 LT = Dest->getLinkage();
387 } else if (Dest->isDeclaration() && !Dest->hasDLLImportLinkage()) {
388 // If Dest is external but Src is not:
390 LT = Src->getLinkage();
391 } else if (Src->hasAppendingLinkage() || Dest->hasAppendingLinkage()) {
392 if (Src->getLinkage() != Dest->getLinkage())
393 return Error(Err, "Linking globals named '" + Src->getName() +
394 "': can only link appending global with another appending global!");
395 LinkFromSrc = true; // Special cased.
396 LT = Src->getLinkage();
397 } else if (Src->hasWeakLinkage() || Src->hasLinkOnceLinkage() ||
398 Src->hasCommonLinkage()) {
399 // At this point we know that Dest has LinkOnce, External*, Weak, Common,
401 if ((Dest->hasLinkOnceLinkage() &&
402 (Src->hasWeakLinkage() || Src->hasCommonLinkage())) ||
403 Dest->hasExternalWeakLinkage()) {
405 LT = Src->getLinkage();
408 LT = Dest->getLinkage();
410 } else if (Dest->hasWeakLinkage() || Dest->hasLinkOnceLinkage() ||
411 Dest->hasCommonLinkage()) {
412 // At this point we know that Src has External* or DLL* linkage.
413 if (Src->hasExternalWeakLinkage()) {
415 LT = Dest->getLinkage();
418 LT = GlobalValue::ExternalLinkage;
421 assert((Dest->hasExternalLinkage() ||
422 Dest->hasDLLImportLinkage() ||
423 Dest->hasDLLExportLinkage() ||
424 Dest->hasExternalWeakLinkage()) &&
425 (Src->hasExternalLinkage() ||
426 Src->hasDLLImportLinkage() ||
427 Src->hasDLLExportLinkage() ||
428 Src->hasExternalWeakLinkage()) &&
429 "Unexpected linkage type!");
430 return Error(Err, "Linking globals named '" + Src->getName() +
431 "': symbol multiply defined!");
435 if (Dest && Src->getVisibility() != Dest->getVisibility())
436 if (!Src->isDeclaration() && !Dest->isDeclaration())
437 return Error(Err, "Linking globals named '" + Src->getName() +
438 "': symbols have different visibilities!");
442 // LinkGlobals - Loop through the global variables in the src module and merge
443 // them into the dest module.
444 static bool LinkGlobals(Module *Dest, const Module *Src,
445 std::map<const Value*, Value*> &ValueMap,
446 std::multimap<std::string, GlobalVariable *> &AppendingVars,
448 // Loop over all of the globals in the src module, mapping them over as we go
449 for (Module::const_global_iterator I = Src->global_begin(), E = Src->global_end();
451 const GlobalVariable *SGV = I;
452 GlobalValue *DGV = 0;
454 // Check to see if may have to link the global with the global
455 if (SGV->hasName() && !SGV->hasInternalLinkage()) {
456 DGV = Dest->getGlobalVariable(SGV->getName());
457 if (DGV && DGV->getType() != SGV->getType())
458 // If types don't agree due to opaque types, try to resolve them.
459 RecursiveResolveTypes(SGV->getType(), DGV->getType());
462 // Check to see if may have to link the global with the alias
463 if (!DGV && SGV->hasName() && !SGV->hasInternalLinkage()) {
464 DGV = Dest->getNamedAlias(SGV->getName());
465 if (DGV && DGV->getType() != SGV->getType())
466 // If types don't agree due to opaque types, try to resolve them.
467 RecursiveResolveTypes(SGV->getType(), DGV->getType());
470 if (DGV && DGV->hasInternalLinkage())
473 assert((SGV->hasInitializer() || SGV->hasExternalWeakLinkage() ||
474 SGV->hasExternalLinkage() || SGV->hasDLLImportLinkage()) &&
475 "Global must either be external or have an initializer!");
477 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage;
478 bool LinkFromSrc = false;
479 if (GetLinkageResult(DGV, SGV, NewLinkage, LinkFromSrc, Err))
483 // No linking to be performed, simply create an identical version of the
484 // symbol over in the dest module... the initializer will be filled in
485 // later by LinkGlobalInits...
486 GlobalVariable *NewDGV =
487 new GlobalVariable(SGV->getType()->getElementType(),
488 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
489 SGV->getName(), Dest);
490 // Propagate alignment, visibility and section info.
491 CopyGVAttributes(NewDGV, SGV);
493 // If the LLVM runtime renamed the global, but it is an externally visible
494 // symbol, DGV must be an existing global with internal linkage. Rename
496 if (NewDGV->getName() != SGV->getName() && !NewDGV->hasInternalLinkage())
497 ForceRenaming(NewDGV, SGV->getName());
499 // Make sure to remember this mapping...
500 ValueMap[SGV] = NewDGV;
502 if (SGV->hasAppendingLinkage())
503 // Keep track that this is an appending variable...
504 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV));
505 } else if (DGV->hasAppendingLinkage()) {
506 // No linking is performed yet. Just insert a new copy of the global, and
507 // keep track of the fact that it is an appending variable in the
508 // AppendingVars map. The name is cleared out so that no linkage is
510 GlobalVariable *NewDGV =
511 new GlobalVariable(SGV->getType()->getElementType(),
512 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
515 // Set alignment allowing CopyGVAttributes merge it with alignment of SGV.
516 NewDGV->setAlignment(DGV->getAlignment());
517 // Propagate alignment, section and visibility info.
518 CopyGVAttributes(NewDGV, SGV);
520 // Make sure to remember this mapping...
521 ValueMap[SGV] = NewDGV;
523 // Keep track that this is an appending variable...
524 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV));
525 } else if (GlobalAlias *DGA = dyn_cast<GlobalAlias>(DGV)) {
526 // SGV is global, but DGV is alias. The only valid mapping is when SGV is
527 // external declaration, which is effectively a no-op. Also make sure
528 // linkage calculation was correct.
529 if (SGV->isDeclaration() && !LinkFromSrc) {
530 // Make sure to remember this mapping...
533 return Error(Err, "Global-Alias Collision on '" + SGV->getName() +
534 "': symbol multiple defined");
535 } else if (GlobalVariable *DGVar = dyn_cast<GlobalVariable>(DGV)) {
536 // Otherwise, perform the global-global mapping as instructed by
539 // Propagate alignment, section, and visibility info.
540 CopyGVAttributes(DGVar, SGV);
542 // If the types don't match, and if we are to link from the source, nuke
543 // DGV and create a new one of the appropriate type.
544 if (SGV->getType() != DGVar->getType()) {
545 GlobalVariable *NewDGV =
546 new GlobalVariable(SGV->getType()->getElementType(),
547 DGVar->isConstant(), DGVar->getLinkage(),
548 /*init*/0, DGVar->getName(), Dest);
549 CopyGVAttributes(NewDGV, DGVar);
550 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDGV,
552 // DGVar will conflict with NewDGV because they both had the same
553 // name. We must erase this now so ForceRenaming doesn't assert
554 // because DGV might not have internal linkage.
555 DGVar->eraseFromParent();
557 // If the symbol table renamed the global, but it is an externally
558 // visible symbol, DGV must be an existing global with internal
559 // linkage. Rename it.
560 if (NewDGV->getName() != SGV->getName() &&
561 !NewDGV->hasInternalLinkage())
562 ForceRenaming(NewDGV, SGV->getName());
567 // Inherit const as appropriate
568 DGVar->setConstant(SGV->isConstant());
570 // Set initializer to zero, so we can link the stuff later
571 DGVar->setInitializer(0);
573 // Special case for const propagation
574 if (DGVar->isDeclaration() && SGV->isConstant() && !DGVar->isConstant())
575 DGVar->setConstant(true);
578 // Set calculated linkage
579 DGVar->setLinkage(NewLinkage);
581 // Make sure to remember this mapping...
582 ValueMap[SGV] = ConstantExpr::getBitCast(DGVar, SGV->getType());
588 static GlobalValue::LinkageTypes
589 CalculateAliasLinkage(const GlobalValue *SGV, const GlobalValue *DGV) {
590 if (SGV->hasExternalLinkage() || DGV->hasExternalLinkage())
591 return GlobalValue::ExternalLinkage;
592 else if (SGV->hasWeakLinkage() || DGV->hasWeakLinkage())
593 return GlobalValue::WeakLinkage;
595 assert(SGV->hasInternalLinkage() && DGV->hasInternalLinkage() &&
596 "Unexpected linkage type");
597 return GlobalValue::InternalLinkage;
601 // LinkAlias - Loop through the alias in the src module and link them into the
602 // dest module. We're assuming, that all functions/global variables were already
604 static bool LinkAlias(Module *Dest, const Module *Src,
605 std::map<const Value*, Value*> &ValueMap,
607 // Loop over all alias in the src module
608 for (Module::const_alias_iterator I = Src->alias_begin(),
609 E = Src->alias_end(); I != E; ++I) {
610 const GlobalAlias *SGA = I;
611 const GlobalValue *SAliasee = SGA->getAliasedGlobal();
612 GlobalAlias *NewGA = NULL;
614 // Globals were already linked, thus we can just query ValueMap for variant
615 // of SAliasee in Dest.
616 std::map<const Value*,Value*>::const_iterator VMI = ValueMap.find(SAliasee);
617 assert(VMI != ValueMap.end() && "Aliasee not linked");
618 GlobalValue* DAliasee = cast<GlobalValue>(VMI->second);
619 GlobalValue* DGV = NULL;
621 // Try to find something 'similar' to SGA in destination module.
622 if (!DGV && !SGA->hasInternalLinkage()) {
623 DGV = Dest->getNamedAlias(SGA->getName());
625 // If types don't agree due to opaque types, try to resolve them.
626 if (DGV && DGV->getType() != SGA->getType())
627 if (RecursiveResolveTypes(SGA->getType(), DGV->getType()))
628 return Error(Err, "Alias Collision on '" + SGA->getName()+
629 "': aliases have different types");
632 if (!DGV && !SGA->hasInternalLinkage()) {
633 DGV = Dest->getGlobalVariable(SGA->getName());
635 // If types don't agree due to opaque types, try to resolve them.
636 if (DGV && DGV->getType() != SGA->getType())
637 if (RecursiveResolveTypes(SGA->getType(), DGV->getType()))
638 return Error(Err, "Alias Collision on '" + SGA->getName()+
639 "': aliases have different types");
642 if (!DGV && !SGA->hasInternalLinkage()) {
643 DGV = Dest->getFunction(SGA->getName());
645 // If types don't agree due to opaque types, try to resolve them.
646 if (DGV && DGV->getType() != SGA->getType())
647 if (RecursiveResolveTypes(SGA->getType(), DGV->getType()))
648 return Error(Err, "Alias Collision on '" + SGA->getName()+
649 "': aliases have different types");
652 // No linking to be performed on internal stuff.
653 if (DGV && DGV->hasInternalLinkage())
656 if (GlobalAlias *DGA = dyn_cast_or_null<GlobalAlias>(DGV)) {
657 // Types are known to be the same, check whether aliasees equal. As
658 // globals are already linked we just need query ValueMap to find the
660 if (DAliasee == DGA->getAliasedGlobal()) {
661 // This is just two copies of the same alias. Propagate linkage, if
663 DGA->setLinkage(CalculateAliasLinkage(SGA, DGA));
666 // Proceed to 'common' steps
668 return Error(Err, "Alias Collision on '" + SGA->getName()+
669 "': aliases have different aliasees");
670 } else if (GlobalVariable *DGVar = dyn_cast_or_null<GlobalVariable>(DGV)) {
671 // The only allowed way is to link alias with external declaration.
672 if (DGVar->isDeclaration()) {
673 // But only if aliasee is global too...
674 if (!isa<GlobalVariable>(DAliasee))
675 return Error(Err, "Global-Alias Collision on '" + SGA->getName() +
676 "': aliasee is not global variable");
678 NewGA = new GlobalAlias(SGA->getType(), SGA->getLinkage(),
679 SGA->getName(), DAliasee, Dest);
680 CopyGVAttributes(NewGA, SGA);
682 // Any uses of DGV need to change to NewGA, with cast, if needed.
683 if (SGA->getType() != DGVar->getType())
684 DGVar->replaceAllUsesWith(ConstantExpr::getBitCast(NewGA,
687 DGVar->replaceAllUsesWith(NewGA);
689 // DGVar will conflict with NewGA because they both had the same
690 // name. We must erase this now so ForceRenaming doesn't assert
691 // because DGV might not have internal linkage.
692 DGVar->eraseFromParent();
694 // Proceed to 'common' steps
696 return Error(Err, "Global-Alias Collision on '" + SGA->getName() +
697 "': symbol multiple defined");
698 } else if (Function *DF = dyn_cast_or_null<Function>(DGV)) {
699 // The only allowed way is to link alias with external declaration.
700 if (DF->isDeclaration()) {
701 // But only if aliasee is function too...
702 if (!isa<Function>(DAliasee))
703 return Error(Err, "Function-Alias Collision on '" + SGA->getName() +
704 "': aliasee is not function");
706 NewGA = new GlobalAlias(SGA->getType(), SGA->getLinkage(),
707 SGA->getName(), DAliasee, Dest);
708 CopyGVAttributes(NewGA, SGA);
710 // Any uses of DF need to change to NewGA, with cast, if needed.
711 if (SGA->getType() != DF->getType())
712 DF->replaceAllUsesWith(ConstantExpr::getBitCast(NewGA,
715 DF->replaceAllUsesWith(NewGA);
717 // DF will conflict with NewGA because they both had the same
718 // name. We must erase this now so ForceRenaming doesn't assert
719 // because DF might not have internal linkage.
720 DF->eraseFromParent();
722 // Proceed to 'common' steps
724 return Error(Err, "Function-Alias Collision on '" + SGA->getName() +
725 "': symbol multiple defined");
727 // No linking to be performed, simply create an identical version of the
728 // alias over in the dest module...
730 NewGA = new GlobalAlias(SGA->getType(), SGA->getLinkage(),
731 SGA->getName(), DAliasee, Dest);
732 CopyGVAttributes(NewGA, SGA);
734 // Proceed to 'common' steps
737 assert(NewGA && "No alias was created in destination module!");
739 // If the symbol table renamed the alias, but it is an externally visible
740 // symbol, DGA must be an global value with internal linkage. Rename it.
741 if (NewGA->getName() != SGA->getName() &&
742 !NewGA->hasInternalLinkage())
743 ForceRenaming(NewGA, SGA->getName());
745 // Remember this mapping so uses in the source module get remapped
746 // later by RemapOperand.
747 ValueMap[SGA] = NewGA;
754 // LinkGlobalInits - Update the initializers in the Dest module now that all
755 // globals that may be referenced are in Dest.
756 static bool LinkGlobalInits(Module *Dest, const Module *Src,
757 std::map<const Value*, Value*> &ValueMap,
760 // Loop over all of the globals in the src module, mapping them over as we go
761 for (Module::const_global_iterator I = Src->global_begin(),
762 E = Src->global_end(); I != E; ++I) {
763 const GlobalVariable *SGV = I;
765 if (SGV->hasInitializer()) { // Only process initialized GV's
766 // Figure out what the initializer looks like in the dest module...
768 cast<Constant>(RemapOperand(SGV->getInitializer(), ValueMap));
770 GlobalVariable *DGV =
771 cast<GlobalVariable>(ValueMap[SGV]->stripPointerCasts());
772 if (DGV->hasInitializer()) {
773 if (SGV->hasExternalLinkage()) {
774 if (DGV->getInitializer() != SInit)
775 return Error(Err, "Global Variable Collision on '" + SGV->getName() +
776 "': global variables have different initializers");
777 } else if (DGV->hasLinkOnceLinkage() || DGV->hasWeakLinkage() ||
778 DGV->hasCommonLinkage()) {
779 // Nothing is required, mapped values will take the new global
781 } else if (SGV->hasLinkOnceLinkage() || SGV->hasWeakLinkage() ||
782 SGV->hasCommonLinkage()) {
783 // Nothing is required, mapped values will take the new global
785 } else if (DGV->hasAppendingLinkage()) {
786 assert(0 && "Appending linkage unimplemented!");
788 assert(0 && "Unknown linkage!");
791 // Copy the initializer over now...
792 DGV->setInitializer(SInit);
799 // LinkFunctionProtos - Link the functions together between the two modules,
800 // without doing function bodies... this just adds external function prototypes
801 // to the Dest function...
803 static bool LinkFunctionProtos(Module *Dest, const Module *Src,
804 std::map<const Value*, Value*> &ValueMap,
806 // Loop over all of the functions in the src module, mapping them over
807 for (Module::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) {
808 const Function *SF = I; // SrcFunction
812 // If this function is internal or has no name, it doesn't participate in
814 if (SF->hasName() && !SF->hasInternalLinkage()) {
815 // Check to see if may have to link the function.
816 DF = Dest->getFunction(SF->getName());
817 if (DF && DF->hasInternalLinkage())
821 // If there is no linkage to be performed, just bring over SF without
824 // Function does not already exist, simply insert an function signature
825 // identical to SF into the dest module.
826 Function *NewDF = Function::Create(SF->getFunctionType(),
828 SF->getName(), Dest);
829 CopyGVAttributes(NewDF, SF);
831 // If the LLVM runtime renamed the function, but it is an externally
832 // visible symbol, DF must be an existing function with internal linkage.
834 if (!NewDF->hasInternalLinkage() && NewDF->getName() != SF->getName())
835 ForceRenaming(NewDF, SF->getName());
837 // ... and remember this mapping...
838 ValueMap[SF] = NewDF;
843 // If types don't agree because of opaque, try to resolve them.
844 if (SF->getType() != DF->getType())
845 RecursiveResolveTypes(SF->getType(), DF->getType());
847 // Check visibility, merging if a definition overrides a prototype.
848 if (SF->getVisibility() != DF->getVisibility()) {
849 // If one is a prototype, ignore its visibility. Prototypes are always
850 // overridden by the definition.
851 if (!SF->isDeclaration() && !DF->isDeclaration())
852 return Error(Err, "Linking functions named '" + SF->getName() +
853 "': symbols have different visibilities!");
855 // Otherwise, replace the visibility of DF if DF is a prototype.
856 if (DF->isDeclaration())
857 DF->setVisibility(SF->getVisibility());
860 if (DF->getType() != SF->getType()) {
861 if (DF->isDeclaration() && !SF->isDeclaration()) {
862 // We have a definition of the same name but different type in the
863 // source module. Copy the prototype to the destination and replace
864 // uses of the destination's prototype with the new prototype.
865 Function *NewDF = Function::Create(SF->getFunctionType(),
867 SF->getName(), Dest);
868 CopyGVAttributes(NewDF, SF);
870 // Any uses of DF need to change to NewDF, with cast
871 DF->replaceAllUsesWith(ConstantExpr::getBitCast(NewDF, DF->getType()));
873 // DF will conflict with NewDF because they both had the same. We must
874 // erase this now so ForceRenaming doesn't assert because DF might
875 // not have internal linkage.
876 DF->eraseFromParent();
878 // If the symbol table renamed the function, but it is an externally
879 // visible symbol, DF must be an existing function with internal
880 // linkage. Rename it.
881 if (NewDF->getName() != SF->getName() && !NewDF->hasInternalLinkage())
882 ForceRenaming(NewDF, SF->getName());
884 // Remember this mapping so uses in the source module get remapped
885 // later by RemapOperand.
886 ValueMap[SF] = NewDF;
887 } else if (SF->isDeclaration()) {
888 // We have two functions of the same name but different type and the
889 // source is a declaration while the destination is not. Any use of
890 // the source must be mapped to the destination, with a cast.
891 ValueMap[SF] = ConstantExpr::getBitCast(DF, SF->getType());
893 // We have two functions of the same name but different types and they
894 // are both definitions. This is an error.
895 return Error(Err, "Function '" + DF->getName() + "' defined as both '" +
896 ToStr(SF->getFunctionType(), Src) + "' and '" +
897 ToStr(DF->getFunctionType(), Dest) + "'");
902 if (SF->isDeclaration()) {
903 // If SF is a declaration or if both SF & DF are declarations, just link
904 // the declarations, we aren't adding anything.
905 if (SF->hasDLLImportLinkage()) {
906 if (DF->isDeclaration()) {
908 DF->setLinkage(SF->getLinkage());
916 // If DF is external but SF is not, link the external functions, update
917 // linkage qualifiers.
918 if (DF->isDeclaration() && !DF->hasDLLImportLinkage()) {
919 ValueMap.insert(std::make_pair(SF, DF));
920 DF->setLinkage(SF->getLinkage());
924 // At this point we know that DF has LinkOnce, Weak, or External* linkage.
925 if (SF->hasWeakLinkage() || SF->hasLinkOnceLinkage() ||
926 SF->hasCommonLinkage()) {
929 // Linkonce+Weak = Weak
930 // *+External Weak = *
931 if ((DF->hasLinkOnceLinkage() &&
932 (SF->hasWeakLinkage() || SF->hasCommonLinkage())) ||
933 DF->hasExternalWeakLinkage())
934 DF->setLinkage(SF->getLinkage());
938 if (DF->hasWeakLinkage() || DF->hasLinkOnceLinkage() ||
939 DF->hasCommonLinkage()) {
940 // At this point we know that SF has LinkOnce or External* linkage.
943 // If the source function has stronger linkage than the destination,
944 // its body and linkage should override ours.
945 if (!SF->hasLinkOnceLinkage() && !SF->hasExternalWeakLinkage()) {
946 // Don't inherit linkonce & external weak linkage.
947 DF->setLinkage(SF->getLinkage());
953 if (SF->getLinkage() != DF->getLinkage())
954 return Error(Err, "Functions named '" + SF->getName() +
955 "' have different linkage specifiers!");
957 // The function is defined identically in both modules!
958 if (SF->hasExternalLinkage())
959 return Error(Err, "Function '" +
960 ToStr(SF->getFunctionType(), Src) + "':\"" +
961 SF->getName() + "\" - Function is already defined!");
962 assert(0 && "Unknown linkage configuration found!");
967 // LinkFunctionBody - Copy the source function over into the dest function and
968 // fix up references to values. At this point we know that Dest is an external
969 // function, and that Src is not.
970 static bool LinkFunctionBody(Function *Dest, Function *Src,
971 std::map<const Value*, Value*> &ValueMap,
973 assert(Src && Dest && Dest->isDeclaration() && !Src->isDeclaration());
975 // Go through and convert function arguments over, remembering the mapping.
976 Function::arg_iterator DI = Dest->arg_begin();
977 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end();
979 DI->setName(I->getName()); // Copy the name information over...
981 // Add a mapping to our local map
985 // Splice the body of the source function into the dest function.
986 Dest->getBasicBlockList().splice(Dest->end(), Src->getBasicBlockList());
988 // At this point, all of the instructions and values of the function are now
989 // copied over. The only problem is that they are still referencing values in
990 // the Source function as operands. Loop through all of the operands of the
991 // functions and patch them up to point to the local versions...
993 for (Function::iterator BB = Dest->begin(), BE = Dest->end(); BB != BE; ++BB)
994 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
995 for (Instruction::op_iterator OI = I->op_begin(), OE = I->op_end();
997 if (!isa<Instruction>(*OI) && !isa<BasicBlock>(*OI))
998 *OI = RemapOperand(*OI, ValueMap);
1000 // There is no need to map the arguments anymore.
1001 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end();
1009 // LinkFunctionBodies - Link in the function bodies that are defined in the
1010 // source module into the DestModule. This consists basically of copying the
1011 // function over and fixing up references to values.
1012 static bool LinkFunctionBodies(Module *Dest, Module *Src,
1013 std::map<const Value*, Value*> &ValueMap,
1016 // Loop over all of the functions in the src module, mapping them over as we
1018 for (Module::iterator SF = Src->begin(), E = Src->end(); SF != E; ++SF) {
1019 if (!SF->isDeclaration()) { // No body if function is external
1020 Function *DF = cast<Function>(ValueMap[SF]); // Destination function
1022 // DF not external SF external?
1023 if (DF->isDeclaration())
1024 // Only provide the function body if there isn't one already.
1025 if (LinkFunctionBody(DF, SF, ValueMap, Err))
1032 // LinkAppendingVars - If there were any appending global variables, link them
1033 // together now. Return true on error.
1034 static bool LinkAppendingVars(Module *M,
1035 std::multimap<std::string, GlobalVariable *> &AppendingVars,
1036 std::string *ErrorMsg) {
1037 if (AppendingVars.empty()) return false; // Nothing to do.
1039 // Loop over the multimap of appending vars, processing any variables with the
1040 // same name, forming a new appending global variable with both of the
1041 // initializers merged together, then rewrite references to the old variables
1043 std::vector<Constant*> Inits;
1044 while (AppendingVars.size() > 1) {
1045 // Get the first two elements in the map...
1046 std::multimap<std::string,
1047 GlobalVariable*>::iterator Second = AppendingVars.begin(), First=Second++;
1049 // If the first two elements are for different names, there is no pair...
1050 // Otherwise there is a pair, so link them together...
1051 if (First->first == Second->first) {
1052 GlobalVariable *G1 = First->second, *G2 = Second->second;
1053 const ArrayType *T1 = cast<ArrayType>(G1->getType()->getElementType());
1054 const ArrayType *T2 = cast<ArrayType>(G2->getType()->getElementType());
1056 // Check to see that they two arrays agree on type...
1057 if (T1->getElementType() != T2->getElementType())
1058 return Error(ErrorMsg,
1059 "Appending variables with different element types need to be linked!");
1060 if (G1->isConstant() != G2->isConstant())
1061 return Error(ErrorMsg,
1062 "Appending variables linked with different const'ness!");
1064 if (G1->getAlignment() != G2->getAlignment())
1065 return Error(ErrorMsg,
1066 "Appending variables with different alignment need to be linked!");
1068 if (G1->getVisibility() != G2->getVisibility())
1069 return Error(ErrorMsg,
1070 "Appending variables with different visibility need to be linked!");
1072 if (G1->getSection() != G2->getSection())
1073 return Error(ErrorMsg,
1074 "Appending variables with different section name need to be linked!");
1076 unsigned NewSize = T1->getNumElements() + T2->getNumElements();
1077 ArrayType *NewType = ArrayType::get(T1->getElementType(), NewSize);
1079 G1->setName(""); // Clear G1's name in case of a conflict!
1081 // Create the new global variable...
1082 GlobalVariable *NG =
1083 new GlobalVariable(NewType, G1->isConstant(), G1->getLinkage(),
1084 /*init*/0, First->first, M, G1->isThreadLocal());
1086 // Propagate alignment, visibility and section info.
1087 CopyGVAttributes(NG, G1);
1089 // Merge the initializer...
1090 Inits.reserve(NewSize);
1091 if (ConstantArray *I = dyn_cast<ConstantArray>(G1->getInitializer())) {
1092 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i)
1093 Inits.push_back(I->getOperand(i));
1095 assert(isa<ConstantAggregateZero>(G1->getInitializer()));
1096 Constant *CV = Constant::getNullValue(T1->getElementType());
1097 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i)
1098 Inits.push_back(CV);
1100 if (ConstantArray *I = dyn_cast<ConstantArray>(G2->getInitializer())) {
1101 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i)
1102 Inits.push_back(I->getOperand(i));
1104 assert(isa<ConstantAggregateZero>(G2->getInitializer()));
1105 Constant *CV = Constant::getNullValue(T2->getElementType());
1106 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i)
1107 Inits.push_back(CV);
1109 NG->setInitializer(ConstantArray::get(NewType, Inits));
1112 // Replace any uses of the two global variables with uses of the new
1115 // FIXME: This should rewrite simple/straight-forward uses such as
1116 // getelementptr instructions to not use the Cast!
1117 G1->replaceAllUsesWith(ConstantExpr::getBitCast(NG, G1->getType()));
1118 G2->replaceAllUsesWith(ConstantExpr::getBitCast(NG, G2->getType()));
1120 // Remove the two globals from the module now...
1121 M->getGlobalList().erase(G1);
1122 M->getGlobalList().erase(G2);
1124 // Put the new global into the AppendingVars map so that we can handle
1125 // linking of more than two vars...
1126 Second->second = NG;
1128 AppendingVars.erase(First);
1134 static bool ResolveAliases(Module *Dest) {
1135 for (Module::alias_iterator I = Dest->alias_begin(), E = Dest->alias_end();
1137 if (const GlobalValue *GV = I->resolveAliasedGlobal())
1138 if (!GV->isDeclaration())
1139 I->replaceAllUsesWith(const_cast<GlobalValue*>(GV));
1144 // LinkModules - This function links two modules together, with the resulting
1145 // left module modified to be the composite of the two input modules. If an
1146 // error occurs, true is returned and ErrorMsg (if not null) is set to indicate
1147 // the problem. Upon failure, the Dest module could be in a modified state, and
1148 // shouldn't be relied on to be consistent.
1150 Linker::LinkModules(Module *Dest, Module *Src, std::string *ErrorMsg) {
1151 assert(Dest != 0 && "Invalid Destination module");
1152 assert(Src != 0 && "Invalid Source Module");
1154 if (Dest->getDataLayout().empty()) {
1155 if (!Src->getDataLayout().empty()) {
1156 Dest->setDataLayout(Src->getDataLayout());
1158 std::string DataLayout;
1160 if (Dest->getEndianness() == Module::AnyEndianness) {
1161 if (Src->getEndianness() == Module::BigEndian)
1162 DataLayout.append("E");
1163 else if (Src->getEndianness() == Module::LittleEndian)
1164 DataLayout.append("e");
1167 if (Dest->getPointerSize() == Module::AnyPointerSize) {
1168 if (Src->getPointerSize() == Module::Pointer64)
1169 DataLayout.append(DataLayout.length() == 0 ? "p:64:64" : "-p:64:64");
1170 else if (Src->getPointerSize() == Module::Pointer32)
1171 DataLayout.append(DataLayout.length() == 0 ? "p:32:32" : "-p:32:32");
1173 Dest->setDataLayout(DataLayout);
1177 // Copy the target triple from the source to dest if the dest's is empty.
1178 if (Dest->getTargetTriple().empty() && !Src->getTargetTriple().empty())
1179 Dest->setTargetTriple(Src->getTargetTriple());
1181 if (!Src->getDataLayout().empty() && !Dest->getDataLayout().empty() &&
1182 Src->getDataLayout() != Dest->getDataLayout())
1183 cerr << "WARNING: Linking two modules of different data layouts!\n";
1184 if (!Src->getTargetTriple().empty() &&
1185 Dest->getTargetTriple() != Src->getTargetTriple())
1186 cerr << "WARNING: Linking two modules of different target triples!\n";
1188 // Append the module inline asm string.
1189 if (!Src->getModuleInlineAsm().empty()) {
1190 if (Dest->getModuleInlineAsm().empty())
1191 Dest->setModuleInlineAsm(Src->getModuleInlineAsm());
1193 Dest->setModuleInlineAsm(Dest->getModuleInlineAsm()+"\n"+
1194 Src->getModuleInlineAsm());
1197 // Update the destination module's dependent libraries list with the libraries
1198 // from the source module. There's no opportunity for duplicates here as the
1199 // Module ensures that duplicate insertions are discarded.
1200 for (Module::lib_iterator SI = Src->lib_begin(), SE = Src->lib_end();
1202 Dest->addLibrary(*SI);
1204 // LinkTypes - Go through the symbol table of the Src module and see if any
1205 // types are named in the src module that are not named in the Dst module.
1206 // Make sure there are no type name conflicts.
1207 if (LinkTypes(Dest, Src, ErrorMsg))
1210 // ValueMap - Mapping of values from what they used to be in Src, to what they
1212 std::map<const Value*, Value*> ValueMap;
1214 // AppendingVars - Keep track of global variables in the destination module
1215 // with appending linkage. After the module is linked together, they are
1216 // appended and the module is rewritten.
1217 std::multimap<std::string, GlobalVariable *> AppendingVars;
1218 for (Module::global_iterator I = Dest->global_begin(), E = Dest->global_end();
1220 // Add all of the appending globals already in the Dest module to
1222 if (I->hasAppendingLinkage())
1223 AppendingVars.insert(std::make_pair(I->getName(), I));
1226 // Insert all of the globals in src into the Dest module... without linking
1227 // initializers (which could refer to functions not yet mapped over).
1228 if (LinkGlobals(Dest, Src, ValueMap, AppendingVars, ErrorMsg))
1231 // Link the functions together between the two modules, without doing function
1232 // bodies... this just adds external function prototypes to the Dest
1233 // function... We do this so that when we begin processing function bodies,
1234 // all of the global values that may be referenced are available in our
1236 if (LinkFunctionProtos(Dest, Src, ValueMap, ErrorMsg))
1239 // If there were any alias, link them now. We really need to do this now,
1240 // because all of the aliases that may be referenced need to be available in
1242 if (LinkAlias(Dest, Src, ValueMap, ErrorMsg)) return true;
1244 // Update the initializers in the Dest module now that all globals that may
1245 // be referenced are in Dest.
1246 if (LinkGlobalInits(Dest, Src, ValueMap, ErrorMsg)) return true;
1248 // Link in the function bodies that are defined in the source module into the
1249 // DestModule. This consists basically of copying the function over and
1250 // fixing up references to values.
1251 if (LinkFunctionBodies(Dest, Src, ValueMap, ErrorMsg)) return true;
1253 // If there were any appending global variables, link them together now.
1254 if (LinkAppendingVars(Dest, AppendingVars, ErrorMsg)) return true;
1256 // Resolve all uses of aliases with aliasees
1257 if (ResolveAliases(Dest)) return true;
1259 // If the source library's module id is in the dependent library list of the
1260 // destination library, remove it since that module is now linked in.
1262 modId.set(Src->getModuleIdentifier());
1263 if (!modId.isEmpty())
1264 Dest->removeLibrary(modId.getBasename());