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"
29 #include "llvm/ADT/DenseMap.h"
33 // Error - Simple wrapper function to conditionally assign to E and return true.
34 // This just makes error return conditions a little bit simpler...
35 static inline bool Error(std::string *E, const std::string &Message) {
40 // Function: ResolveTypes()
43 // Attempt to link the two specified types together.
46 // DestTy - The type to which we wish to resolve.
47 // SrcTy - The original type which we want to resolve.
50 // DestST - The symbol table in which the new type should be placed.
53 // true - There is an error and the types cannot yet be linked.
56 static bool ResolveTypes(const Type *DestTy, const Type *SrcTy) {
57 if (DestTy == SrcTy) return false; // If already equal, noop
58 assert(DestTy && SrcTy && "Can't handle null types");
60 if (const OpaqueType *OT = dyn_cast<OpaqueType>(DestTy)) {
61 // Type _is_ in module, just opaque...
62 const_cast<OpaqueType*>(OT)->refineAbstractTypeTo(SrcTy);
63 } else if (const OpaqueType *OT = dyn_cast<OpaqueType>(SrcTy)) {
64 const_cast<OpaqueType*>(OT)->refineAbstractTypeTo(DestTy);
66 return true; // Cannot link types... not-equal and neither is opaque.
71 /// LinkerTypeMap - This implements a map of types that is stable
72 /// even if types are resolved/refined to other types. This is not a general
73 /// purpose map, it is specific to the linker's use.
75 class LinkerTypeMap : public AbstractTypeUser {
76 typedef DenseMap<const Type*, PATypeHolder> TheMapTy;
79 LinkerTypeMap(const LinkerTypeMap&); // DO NOT IMPLEMENT
80 void operator=(const LinkerTypeMap&); // DO NOT IMPLEMENT
84 for (DenseMap<const Type*, PATypeHolder>::iterator I = TheMap.begin(),
85 E = TheMap.end(); I != E; ++I)
86 I->first->removeAbstractTypeUser(this);
89 /// lookup - Return the value for the specified type or null if it doesn't
91 const Type *lookup(const Type *Ty) const {
92 TheMapTy::const_iterator I = TheMap.find(Ty);
93 if (I != TheMap.end()) return I->second;
97 /// erase - Remove the specified type, returning true if it was in the set.
98 bool erase(const Type *Ty) {
99 if (!TheMap.erase(Ty))
101 if (Ty->isAbstract())
102 Ty->removeAbstractTypeUser(this);
106 /// insert - This returns true if the pointer was new to the set, false if it
107 /// was already in the set.
108 bool insert(const Type *Src, const Type *Dst) {
109 if (!TheMap.insert(std::make_pair(Src, PATypeHolder(Dst))).second)
110 return false; // Already in map.
111 if (Src->isAbstract())
112 Src->addAbstractTypeUser(this);
117 /// refineAbstractType - The callback method invoked when an abstract type is
118 /// resolved to another type. An object must override this method to update
119 /// its internal state to reference NewType instead of OldType.
121 virtual void refineAbstractType(const DerivedType *OldTy,
123 TheMapTy::iterator I = TheMap.find(OldTy);
124 const Type *DstTy = I->second;
127 if (OldTy->isAbstract())
128 OldTy->removeAbstractTypeUser(this);
130 // Don't reinsert into the map if the key is concrete now.
131 if (NewTy->isAbstract())
132 insert(NewTy, DstTy);
135 /// The other case which AbstractTypeUsers must be aware of is when a type
136 /// makes the transition from being abstract (where it has clients on it's
137 /// AbstractTypeUsers list) to concrete (where it does not). This method
138 /// notifies ATU's when this occurs for a type.
139 virtual void typeBecameConcrete(const DerivedType *AbsTy) {
141 AbsTy->removeAbstractTypeUser(this);
145 virtual void dump() const {
146 cerr << "AbstractTypeSet!\n";
152 // RecursiveResolveTypes - This is just like ResolveTypes, except that it
153 // recurses down into derived types, merging the used types if the parent types
155 static bool RecursiveResolveTypesI(const Type *DstTy, const Type *SrcTy,
156 LinkerTypeMap &Pointers) {
157 if (DstTy == SrcTy) return false; // If already equal, noop
159 // If we found our opaque type, resolve it now!
160 if (isa<OpaqueType>(DstTy) || isa<OpaqueType>(SrcTy))
161 return ResolveTypes(DstTy, SrcTy);
163 // Two types cannot be resolved together if they are of different primitive
164 // type. For example, we cannot resolve an int to a float.
165 if (DstTy->getTypeID() != SrcTy->getTypeID()) return true;
167 // If neither type is abstract, then they really are just different types.
168 if (!DstTy->isAbstract() && !SrcTy->isAbstract())
171 // Otherwise, resolve the used type used by this derived type...
172 switch (DstTy->getTypeID()) {
175 case Type::FunctionTyID: {
176 const FunctionType *DstFT = cast<FunctionType>(DstTy);
177 const FunctionType *SrcFT = cast<FunctionType>(SrcTy);
178 if (DstFT->isVarArg() != SrcFT->isVarArg() ||
179 DstFT->getNumContainedTypes() != SrcFT->getNumContainedTypes())
182 // Use TypeHolder's so recursive resolution won't break us.
183 PATypeHolder ST(SrcFT), DT(DstFT);
184 for (unsigned i = 0, e = DstFT->getNumContainedTypes(); i != e; ++i) {
185 const Type *SE = ST->getContainedType(i), *DE = DT->getContainedType(i);
186 if (SE != DE && RecursiveResolveTypesI(DE, SE, Pointers))
191 case Type::StructTyID: {
192 const StructType *DstST = cast<StructType>(DstTy);
193 const StructType *SrcST = cast<StructType>(SrcTy);
194 if (DstST->getNumContainedTypes() != SrcST->getNumContainedTypes())
197 PATypeHolder ST(SrcST), DT(DstST);
198 for (unsigned i = 0, e = DstST->getNumContainedTypes(); i != e; ++i) {
199 const Type *SE = ST->getContainedType(i), *DE = DT->getContainedType(i);
200 if (SE != DE && RecursiveResolveTypesI(DE, SE, Pointers))
205 case Type::ArrayTyID: {
206 const ArrayType *DAT = cast<ArrayType>(DstTy);
207 const ArrayType *SAT = cast<ArrayType>(SrcTy);
208 if (DAT->getNumElements() != SAT->getNumElements()) return true;
209 return RecursiveResolveTypesI(DAT->getElementType(), SAT->getElementType(),
212 case Type::VectorTyID: {
213 const VectorType *DVT = cast<VectorType>(DstTy);
214 const VectorType *SVT = cast<VectorType>(SrcTy);
215 if (DVT->getNumElements() != SVT->getNumElements()) return true;
216 return RecursiveResolveTypesI(DVT->getElementType(), SVT->getElementType(),
219 case Type::PointerTyID: {
220 const PointerType *DstPT = cast<PointerType>(DstTy);
221 const PointerType *SrcPT = cast<PointerType>(SrcTy);
223 if (DstPT->getAddressSpace() != SrcPT->getAddressSpace())
226 // If this is a pointer type, check to see if we have already seen it. If
227 // so, we are in a recursive branch. Cut off the search now. We cannot use
228 // an associative container for this search, because the type pointers (keys
229 // in the container) change whenever types get resolved.
230 if (SrcPT->isAbstract())
231 if (const Type *ExistingDestTy = Pointers.lookup(SrcPT))
232 return ExistingDestTy != DstPT;
234 if (DstPT->isAbstract())
235 if (const Type *ExistingSrcTy = Pointers.lookup(DstPT))
236 return ExistingSrcTy != SrcPT;
237 // Otherwise, add the current pointers to the vector to stop recursion on
239 if (DstPT->isAbstract())
240 Pointers.insert(DstPT, SrcPT);
241 if (SrcPT->isAbstract())
242 Pointers.insert(SrcPT, DstPT);
244 return RecursiveResolveTypesI(DstPT->getElementType(),
245 SrcPT->getElementType(), Pointers);
250 static bool RecursiveResolveTypes(const Type *DestTy, const Type *SrcTy) {
251 LinkerTypeMap PointerTypes;
252 return RecursiveResolveTypesI(DestTy, SrcTy, PointerTypes);
256 // LinkTypes - Go through the symbol table of the Src module and see if any
257 // types are named in the src module that are not named in the Dst module.
258 // Make sure there are no type name conflicts.
259 static bool LinkTypes(Module *Dest, const Module *Src, std::string *Err) {
260 TypeSymbolTable *DestST = &Dest->getTypeSymbolTable();
261 const TypeSymbolTable *SrcST = &Src->getTypeSymbolTable();
263 // Look for a type plane for Type's...
264 TypeSymbolTable::const_iterator TI = SrcST->begin();
265 TypeSymbolTable::const_iterator TE = SrcST->end();
266 if (TI == TE) return false; // No named types, do nothing.
268 // Some types cannot be resolved immediately because they depend on other
269 // types being resolved to each other first. This contains a list of types we
270 // are waiting to recheck.
271 std::vector<std::string> DelayedTypesToResolve;
273 for ( ; TI != TE; ++TI ) {
274 const std::string &Name = TI->first;
275 const Type *RHS = TI->second;
277 // Check to see if this type name is already in the dest module.
278 Type *Entry = DestST->lookup(Name);
280 // If the name is just in the source module, bring it over to the dest.
283 DestST->insert(Name, const_cast<Type*>(RHS));
284 } else if (ResolveTypes(Entry, RHS)) {
285 // They look different, save the types 'till later to resolve.
286 DelayedTypesToResolve.push_back(Name);
290 // Iteratively resolve types while we can...
291 while (!DelayedTypesToResolve.empty()) {
292 // Loop over all of the types, attempting to resolve them if possible...
293 unsigned OldSize = DelayedTypesToResolve.size();
295 // Try direct resolution by name...
296 for (unsigned i = 0; i != DelayedTypesToResolve.size(); ++i) {
297 const std::string &Name = DelayedTypesToResolve[i];
298 Type *T1 = SrcST->lookup(Name);
299 Type *T2 = DestST->lookup(Name);
300 if (!ResolveTypes(T2, T1)) {
301 // We are making progress!
302 DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i);
307 // Did we not eliminate any types?
308 if (DelayedTypesToResolve.size() == OldSize) {
309 // Attempt to resolve subelements of types. This allows us to merge these
310 // two types: { int* } and { opaque* }
311 for (unsigned i = 0, e = DelayedTypesToResolve.size(); i != e; ++i) {
312 const std::string &Name = DelayedTypesToResolve[i];
313 if (!RecursiveResolveTypes(SrcST->lookup(Name), DestST->lookup(Name))) {
314 // We are making progress!
315 DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i);
317 // Go back to the main loop, perhaps we can resolve directly by name
323 // If we STILL cannot resolve the types, then there is something wrong.
324 if (DelayedTypesToResolve.size() == OldSize) {
325 // Remove the symbol name from the destination.
326 DelayedTypesToResolve.pop_back();
336 static void PrintMap(const std::map<const Value*, Value*> &M) {
337 for (std::map<const Value*, Value*>::const_iterator I = M.begin(), E =M.end();
339 cerr << " Fr: " << (void*)I->first << " ";
341 cerr << " To: " << (void*)I->second << " ";
349 // RemapOperand - Use ValueMap to convert constants from one module to another.
350 static Value *RemapOperand(const Value *In,
351 std::map<const Value*, Value*> &ValueMap) {
352 std::map<const Value*,Value*>::const_iterator I = ValueMap.find(In);
353 if (I != ValueMap.end())
356 // Check to see if it's a constant that we are interested in transforming.
358 if (const Constant *CPV = dyn_cast<Constant>(In)) {
359 if ((!isa<DerivedType>(CPV->getType()) && !isa<ConstantExpr>(CPV)) ||
360 isa<ConstantInt>(CPV) || isa<ConstantAggregateZero>(CPV))
361 return const_cast<Constant*>(CPV); // Simple constants stay identical.
363 if (const ConstantArray *CPA = dyn_cast<ConstantArray>(CPV)) {
364 std::vector<Constant*> Operands(CPA->getNumOperands());
365 for (unsigned i = 0, e = CPA->getNumOperands(); i != e; ++i)
366 Operands[i] =cast<Constant>(RemapOperand(CPA->getOperand(i), ValueMap));
367 Result = ConstantArray::get(cast<ArrayType>(CPA->getType()), Operands);
368 } else if (const ConstantStruct *CPS = dyn_cast<ConstantStruct>(CPV)) {
369 std::vector<Constant*> Operands(CPS->getNumOperands());
370 for (unsigned i = 0, e = CPS->getNumOperands(); i != e; ++i)
371 Operands[i] =cast<Constant>(RemapOperand(CPS->getOperand(i), ValueMap));
372 Result = ConstantStruct::get(cast<StructType>(CPS->getType()), Operands);
373 } else if (isa<ConstantPointerNull>(CPV) || isa<UndefValue>(CPV)) {
374 Result = const_cast<Constant*>(CPV);
375 } else if (const ConstantVector *CP = dyn_cast<ConstantVector>(CPV)) {
376 std::vector<Constant*> Operands(CP->getNumOperands());
377 for (unsigned i = 0, e = CP->getNumOperands(); i != e; ++i)
378 Operands[i] = cast<Constant>(RemapOperand(CP->getOperand(i), ValueMap));
379 Result = ConstantVector::get(Operands);
380 } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CPV)) {
381 std::vector<Constant*> Ops;
382 for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i)
383 Ops.push_back(cast<Constant>(RemapOperand(CE->getOperand(i),ValueMap)));
384 Result = CE->getWithOperands(Ops);
386 assert(!isa<GlobalValue>(CPV) && "Unmapped global?");
387 assert(0 && "Unknown type of derived type constant value!");
389 } else if (isa<InlineAsm>(In)) {
390 Result = const_cast<Value*>(In);
393 // Cache the mapping in our local map structure
395 ValueMap[In] = Result;
400 cerr << "LinkModules ValueMap: \n";
403 cerr << "Couldn't remap value: " << (void*)In << " " << *In << "\n";
404 assert(0 && "Couldn't remap value!");
409 /// ForceRenaming - The LLVM SymbolTable class autorenames globals that conflict
410 /// in the symbol table. This is good for all clients except for us. Go
411 /// through the trouble to force this back.
412 static void ForceRenaming(GlobalValue *GV, const std::string &Name) {
413 assert(GV->getName() != Name && "Can't force rename to self");
414 ValueSymbolTable &ST = GV->getParent()->getValueSymbolTable();
416 // If there is a conflict, rename the conflict.
417 if (GlobalValue *ConflictGV = cast_or_null<GlobalValue>(ST.lookup(Name))) {
418 assert(ConflictGV->hasLocalLinkage() &&
419 "Not conflicting with a static global, should link instead!");
420 GV->takeName(ConflictGV);
421 ConflictGV->setName(Name); // This will cause ConflictGV to get renamed
422 assert(ConflictGV->getName() != Name && "ForceRenaming didn't work");
424 GV->setName(Name); // Force the name back
428 /// CopyGVAttributes - copy additional attributes (those not needed to construct
429 /// a GlobalValue) from the SrcGV to the DestGV.
430 static void CopyGVAttributes(GlobalValue *DestGV, const GlobalValue *SrcGV) {
431 // Use the maximum alignment, rather than just copying the alignment of SrcGV.
432 unsigned Alignment = std::max(DestGV->getAlignment(), SrcGV->getAlignment());
433 DestGV->copyAttributesFrom(SrcGV);
434 DestGV->setAlignment(Alignment);
437 /// GetLinkageResult - This analyzes the two global values and determines what
438 /// the result will look like in the destination module. In particular, it
439 /// computes the resultant linkage type, computes whether the global in the
440 /// source should be copied over to the destination (replacing the existing
441 /// one), and computes whether this linkage is an error or not. It also performs
442 /// visibility checks: we cannot link together two symbols with different
444 static bool GetLinkageResult(GlobalValue *Dest, const GlobalValue *Src,
445 GlobalValue::LinkageTypes <, bool &LinkFromSrc,
447 assert((!Dest || !Src->hasLocalLinkage()) &&
448 "If Src has internal linkage, Dest shouldn't be set!");
450 // Linking something to nothing.
452 LT = Src->getLinkage();
453 } else if (Src->isDeclaration()) {
454 // If Src is external or if both Src & Dest are external.. Just link the
455 // external globals, we aren't adding anything.
456 if (Src->hasDLLImportLinkage()) {
457 // If one of GVs has DLLImport linkage, result should be dllimport'ed.
458 if (Dest->isDeclaration()) {
460 LT = Src->getLinkage();
462 } else if (Dest->hasExternalWeakLinkage()) {
463 // If the Dest is weak, use the source linkage.
465 LT = Src->getLinkage();
468 LT = Dest->getLinkage();
470 } else if (Dest->isDeclaration() && !Dest->hasDLLImportLinkage()) {
471 // If Dest is external but Src is not:
473 LT = Src->getLinkage();
474 } else if (Src->hasAppendingLinkage() || Dest->hasAppendingLinkage()) {
475 if (Src->getLinkage() != Dest->getLinkage())
476 return Error(Err, "Linking globals named '" + Src->getName() +
477 "': can only link appending global with another appending global!");
478 LinkFromSrc = true; // Special cased.
479 LT = Src->getLinkage();
480 } else if (Src->isWeakForLinker()) {
481 // At this point we know that Dest has LinkOnce, External*, Weak, Common,
483 if ((Dest->hasLinkOnceLinkage() &&
484 (Src->hasWeakLinkage() || Src->hasCommonLinkage())) ||
485 Dest->hasExternalWeakLinkage()) {
487 LT = Src->getLinkage();
490 LT = Dest->getLinkage();
492 } else if (Dest->isWeakForLinker()) {
493 // At this point we know that Src has External* or DLL* linkage.
494 if (Src->hasExternalWeakLinkage()) {
496 LT = Dest->getLinkage();
499 LT = GlobalValue::ExternalLinkage;
502 assert((Dest->hasExternalLinkage() ||
503 Dest->hasDLLImportLinkage() ||
504 Dest->hasDLLExportLinkage() ||
505 Dest->hasExternalWeakLinkage()) &&
506 (Src->hasExternalLinkage() ||
507 Src->hasDLLImportLinkage() ||
508 Src->hasDLLExportLinkage() ||
509 Src->hasExternalWeakLinkage()) &&
510 "Unexpected linkage type!");
511 return Error(Err, "Linking globals named '" + Src->getName() +
512 "': symbol multiply defined!");
516 if (Dest && Src->getVisibility() != Dest->getVisibility())
517 if (!Src->isDeclaration() && !Dest->isDeclaration())
518 return Error(Err, "Linking globals named '" + Src->getName() +
519 "': symbols have different visibilities!");
523 // LinkGlobals - Loop through the global variables in the src module and merge
524 // them into the dest module.
525 static bool LinkGlobals(Module *Dest, const Module *Src,
526 std::map<const Value*, Value*> &ValueMap,
527 std::multimap<std::string, GlobalVariable *> &AppendingVars,
529 ValueSymbolTable &DestSymTab = Dest->getValueSymbolTable();
531 // Loop over all of the globals in the src module, mapping them over as we go
532 for (Module::const_global_iterator I = Src->global_begin(),
533 E = Src->global_end(); I != E; ++I) {
534 const GlobalVariable *SGV = I;
535 GlobalValue *DGV = 0;
537 // Check to see if may have to link the global with the global, alias or
539 if (SGV->hasName() && !SGV->hasLocalLinkage())
540 DGV = cast_or_null<GlobalValue>(DestSymTab.lookup(SGV->getNameStart(),
543 // If we found a global with the same name in the dest module, but it has
544 // internal linkage, we are really not doing any linkage here.
545 if (DGV && DGV->hasLocalLinkage())
548 // If types don't agree due to opaque types, try to resolve them.
549 if (DGV && DGV->getType() != SGV->getType())
550 RecursiveResolveTypes(SGV->getType(), DGV->getType());
552 assert((SGV->hasInitializer() || SGV->hasExternalWeakLinkage() ||
553 SGV->hasExternalLinkage() || SGV->hasDLLImportLinkage()) &&
554 "Global must either be external or have an initializer!");
556 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage;
557 bool LinkFromSrc = false;
558 if (GetLinkageResult(DGV, SGV, NewLinkage, LinkFromSrc, Err))
562 // No linking to be performed, simply create an identical version of the
563 // symbol over in the dest module... the initializer will be filled in
564 // later by LinkGlobalInits.
565 GlobalVariable *NewDGV =
566 new GlobalVariable(SGV->getType()->getElementType(),
567 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
568 SGV->getName(), Dest, false,
569 SGV->getType()->getAddressSpace());
570 // Propagate alignment, visibility and section info.
571 CopyGVAttributes(NewDGV, SGV);
573 // If the LLVM runtime renamed the global, but it is an externally visible
574 // symbol, DGV must be an existing global with internal linkage. Rename
576 if (!NewDGV->hasLocalLinkage() && NewDGV->getName() != SGV->getName())
577 ForceRenaming(NewDGV, SGV->getName());
579 // Make sure to remember this mapping.
580 ValueMap[SGV] = NewDGV;
582 // Keep track that this is an appending variable.
583 if (SGV->hasAppendingLinkage())
584 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV));
588 // If the visibilities of the symbols disagree and the destination is a
589 // prototype, take the visibility of its input.
590 if (DGV->isDeclaration())
591 DGV->setVisibility(SGV->getVisibility());
593 if (DGV->hasAppendingLinkage()) {
594 // No linking is performed yet. Just insert a new copy of the global, and
595 // keep track of the fact that it is an appending variable in the
596 // AppendingVars map. The name is cleared out so that no linkage is
598 GlobalVariable *NewDGV =
599 new GlobalVariable(SGV->getType()->getElementType(),
600 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
602 SGV->getType()->getAddressSpace());
604 // Set alignment allowing CopyGVAttributes merge it with alignment of SGV.
605 NewDGV->setAlignment(DGV->getAlignment());
606 // Propagate alignment, section and visibility info.
607 CopyGVAttributes(NewDGV, SGV);
609 // Make sure to remember this mapping...
610 ValueMap[SGV] = NewDGV;
612 // Keep track that this is an appending variable...
613 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV));
618 if (isa<GlobalAlias>(DGV))
619 return Error(Err, "Global-Alias Collision on '" + SGV->getName() +
620 "': symbol multiple defined");
622 // If the types don't match, and if we are to link from the source, nuke
623 // DGV and create a new one of the appropriate type. Note that the thing
624 // we are replacing may be a function (if a prototype, weak, etc) or a
626 GlobalVariable *NewDGV =
627 new GlobalVariable(SGV->getType()->getElementType(), SGV->isConstant(),
628 NewLinkage, /*init*/0, DGV->getName(), Dest, false,
629 SGV->getType()->getAddressSpace());
631 // Propagate alignment, section, and visibility info.
632 CopyGVAttributes(NewDGV, SGV);
633 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDGV, DGV->getType()));
635 // DGV will conflict with NewDGV because they both had the same
636 // name. We must erase this now so ForceRenaming doesn't assert
637 // because DGV might not have internal linkage.
638 if (GlobalVariable *Var = dyn_cast<GlobalVariable>(DGV))
639 Var->eraseFromParent();
641 cast<Function>(DGV)->eraseFromParent();
644 // If the symbol table renamed the global, but it is an externally visible
645 // symbol, DGV must be an existing global with internal linkage. Rename.
646 if (NewDGV->getName() != SGV->getName() && !NewDGV->hasLocalLinkage())
647 ForceRenaming(NewDGV, SGV->getName());
649 // Inherit const as appropriate.
650 NewDGV->setConstant(SGV->isConstant());
652 // Make sure to remember this mapping.
653 ValueMap[SGV] = NewDGV;
657 // Not "link from source", keep the one in the DestModule and remap the
660 // Special case for const propagation.
661 if (GlobalVariable *DGVar = dyn_cast<GlobalVariable>(DGV))
662 if (DGVar->isDeclaration() && SGV->isConstant() && !DGVar->isConstant())
663 DGVar->setConstant(true);
665 // SGV is global, but DGV is alias.
666 if (isa<GlobalAlias>(DGV)) {
667 // The only valid mappings are:
668 // - SGV is external declaration, which is effectively a no-op.
669 // - SGV is weak, when we just need to throw SGV out.
670 if (!SGV->isDeclaration() && !SGV->isWeakForLinker())
671 return Error(Err, "Global-Alias Collision on '" + SGV->getName() +
672 "': symbol multiple defined");
675 // Set calculated linkage
676 DGV->setLinkage(NewLinkage);
678 // Make sure to remember this mapping...
679 ValueMap[SGV] = ConstantExpr::getBitCast(DGV, SGV->getType());
684 static GlobalValue::LinkageTypes
685 CalculateAliasLinkage(const GlobalValue *SGV, const GlobalValue *DGV) {
686 GlobalValue::LinkageTypes SL = SGV->getLinkage();
687 GlobalValue::LinkageTypes DL = DGV->getLinkage();
688 if (SL == GlobalValue::ExternalLinkage || DL == GlobalValue::ExternalLinkage)
689 return GlobalValue::ExternalLinkage;
690 else if (SL == GlobalValue::WeakAnyLinkage ||
691 DL == GlobalValue::WeakAnyLinkage)
692 return GlobalValue::WeakAnyLinkage;
693 else if (SL == GlobalValue::WeakODRLinkage ||
694 DL == GlobalValue::WeakODRLinkage)
695 return GlobalValue::WeakODRLinkage;
696 else if (SL == GlobalValue::InternalLinkage &&
697 DL == GlobalValue::InternalLinkage)
698 return GlobalValue::InternalLinkage;
700 assert (SL == GlobalValue::PrivateLinkage &&
701 DL == GlobalValue::PrivateLinkage && "Unexpected linkage type");
702 return GlobalValue::PrivateLinkage;
706 // LinkAlias - Loop through the alias in the src module and link them into the
707 // dest module. We're assuming, that all functions/global variables were already
709 static bool LinkAlias(Module *Dest, const Module *Src,
710 std::map<const Value*, Value*> &ValueMap,
712 // Loop over all alias in the src module
713 for (Module::const_alias_iterator I = Src->alias_begin(),
714 E = Src->alias_end(); I != E; ++I) {
715 const GlobalAlias *SGA = I;
716 const GlobalValue *SAliasee = SGA->getAliasedGlobal();
717 GlobalAlias *NewGA = NULL;
719 // Globals were already linked, thus we can just query ValueMap for variant
720 // of SAliasee in Dest.
721 std::map<const Value*,Value*>::const_iterator VMI = ValueMap.find(SAliasee);
722 assert(VMI != ValueMap.end() && "Aliasee not linked");
723 GlobalValue* DAliasee = cast<GlobalValue>(VMI->second);
724 GlobalValue* DGV = NULL;
726 // Try to find something 'similar' to SGA in destination module.
727 if (!DGV && !SGA->hasLocalLinkage()) {
728 DGV = Dest->getNamedAlias(SGA->getName());
730 // If types don't agree due to opaque types, try to resolve them.
731 if (DGV && DGV->getType() != SGA->getType())
732 RecursiveResolveTypes(SGA->getType(), DGV->getType());
735 if (!DGV && !SGA->hasLocalLinkage()) {
736 DGV = Dest->getGlobalVariable(SGA->getName());
738 // If types don't agree due to opaque types, try to resolve them.
739 if (DGV && DGV->getType() != SGA->getType())
740 RecursiveResolveTypes(SGA->getType(), DGV->getType());
743 if (!DGV && !SGA->hasLocalLinkage()) {
744 DGV = Dest->getFunction(SGA->getName());
746 // If types don't agree due to opaque types, try to resolve them.
747 if (DGV && DGV->getType() != SGA->getType())
748 RecursiveResolveTypes(SGA->getType(), DGV->getType());
751 // No linking to be performed on internal stuff.
752 if (DGV && DGV->hasLocalLinkage())
755 if (GlobalAlias *DGA = dyn_cast_or_null<GlobalAlias>(DGV)) {
756 // Types are known to be the same, check whether aliasees equal. As
757 // globals are already linked we just need query ValueMap to find the
759 if (DAliasee == DGA->getAliasedGlobal()) {
760 // This is just two copies of the same alias. Propagate linkage, if
762 DGA->setLinkage(CalculateAliasLinkage(SGA, DGA));
765 // Proceed to 'common' steps
767 return Error(Err, "Alias Collision on '" + SGA->getName()+
768 "': aliases have different aliasees");
769 } else if (GlobalVariable *DGVar = dyn_cast_or_null<GlobalVariable>(DGV)) {
770 // The only allowed way is to link alias with external declaration or weak
772 if (DGVar->isDeclaration() || DGVar->isWeakForLinker()) {
773 // But only if aliasee is global too...
774 if (!isa<GlobalVariable>(DAliasee))
775 return Error(Err, "Global-Alias Collision on '" + SGA->getName() +
776 "': aliasee is not global variable");
778 NewGA = new GlobalAlias(SGA->getType(), SGA->getLinkage(),
779 SGA->getName(), DAliasee, Dest);
780 CopyGVAttributes(NewGA, SGA);
782 // Any uses of DGV need to change to NewGA, with cast, if needed.
783 if (SGA->getType() != DGVar->getType())
784 DGVar->replaceAllUsesWith(ConstantExpr::getBitCast(NewGA,
787 DGVar->replaceAllUsesWith(NewGA);
789 // DGVar will conflict with NewGA because they both had the same
790 // name. We must erase this now so ForceRenaming doesn't assert
791 // because DGV might not have internal linkage.
792 DGVar->eraseFromParent();
794 // Proceed to 'common' steps
796 return Error(Err, "Global-Alias Collision on '" + SGA->getName() +
797 "': symbol multiple defined");
798 } else if (Function *DF = dyn_cast_or_null<Function>(DGV)) {
799 // The only allowed way is to link alias with external declaration or weak
801 if (DF->isDeclaration() || DF->isWeakForLinker()) {
802 // But only if aliasee is function too...
803 if (!isa<Function>(DAliasee))
804 return Error(Err, "Function-Alias Collision on '" + SGA->getName() +
805 "': aliasee is not function");
807 NewGA = new GlobalAlias(SGA->getType(), SGA->getLinkage(),
808 SGA->getName(), DAliasee, Dest);
809 CopyGVAttributes(NewGA, SGA);
811 // Any uses of DF need to change to NewGA, with cast, if needed.
812 if (SGA->getType() != DF->getType())
813 DF->replaceAllUsesWith(ConstantExpr::getBitCast(NewGA,
816 DF->replaceAllUsesWith(NewGA);
818 // DF will conflict with NewGA because they both had the same
819 // name. We must erase this now so ForceRenaming doesn't assert
820 // because DF might not have internal linkage.
821 DF->eraseFromParent();
823 // Proceed to 'common' steps
825 return Error(Err, "Function-Alias Collision on '" + SGA->getName() +
826 "': symbol multiple defined");
828 // No linking to be performed, simply create an identical version of the
829 // alias over in the dest module...
831 NewGA = new GlobalAlias(SGA->getType(), SGA->getLinkage(),
832 SGA->getName(), DAliasee, Dest);
833 CopyGVAttributes(NewGA, SGA);
835 // Proceed to 'common' steps
838 assert(NewGA && "No alias was created in destination module!");
840 // If the symbol table renamed the alias, but it is an externally visible
841 // symbol, DGA must be an global value with internal linkage. Rename it.
842 if (NewGA->getName() != SGA->getName() &&
843 !NewGA->hasLocalLinkage())
844 ForceRenaming(NewGA, SGA->getName());
846 // Remember this mapping so uses in the source module get remapped
847 // later by RemapOperand.
848 ValueMap[SGA] = NewGA;
855 // LinkGlobalInits - Update the initializers in the Dest module now that all
856 // globals that may be referenced are in Dest.
857 static bool LinkGlobalInits(Module *Dest, const Module *Src,
858 std::map<const Value*, Value*> &ValueMap,
860 // Loop over all of the globals in the src module, mapping them over as we go
861 for (Module::const_global_iterator I = Src->global_begin(),
862 E = Src->global_end(); I != E; ++I) {
863 const GlobalVariable *SGV = I;
865 if (SGV->hasInitializer()) { // Only process initialized GV's
866 // Figure out what the initializer looks like in the dest module...
868 cast<Constant>(RemapOperand(SGV->getInitializer(), ValueMap));
869 // Grab destination global variable or alias.
870 GlobalValue *DGV = cast<GlobalValue>(ValueMap[SGV]->stripPointerCasts());
872 // If dest if global variable, check that initializers match.
873 if (GlobalVariable *DGVar = dyn_cast<GlobalVariable>(DGV)) {
874 if (DGVar->hasInitializer()) {
875 if (SGV->hasExternalLinkage()) {
876 if (DGVar->getInitializer() != SInit)
877 return Error(Err, "Global Variable Collision on '" +
879 "': global variables have different initializers");
880 } else if (DGVar->isWeakForLinker()) {
881 // Nothing is required, mapped values will take the new global
883 } else if (SGV->isWeakForLinker()) {
884 // Nothing is required, mapped values will take the new global
886 } else if (DGVar->hasAppendingLinkage()) {
887 assert(0 && "Appending linkage unimplemented!");
889 assert(0 && "Unknown linkage!");
892 // Copy the initializer over now...
893 DGVar->setInitializer(SInit);
896 // Destination is alias, the only valid situation is when source is
897 // weak. Also, note, that we already checked linkage in LinkGlobals(),
898 // thus we assert here.
899 // FIXME: Should we weaken this assumption, 'dereference' alias and
900 // check for initializer of aliasee?
901 assert(SGV->isWeakForLinker());
908 // LinkFunctionProtos - Link the functions together between the two modules,
909 // without doing function bodies... this just adds external function prototypes
910 // to the Dest function...
912 static bool LinkFunctionProtos(Module *Dest, const Module *Src,
913 std::map<const Value*, Value*> &ValueMap,
915 ValueSymbolTable &DestSymTab = Dest->getValueSymbolTable();
917 // Loop over all of the functions in the src module, mapping them over
918 for (Module::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) {
919 const Function *SF = I; // SrcFunction
920 GlobalValue *DGV = 0;
922 // Check to see if may have to link the function with the global, alias or
924 if (SF->hasName() && !SF->hasLocalLinkage())
925 DGV = cast_or_null<GlobalValue>(DestSymTab.lookup(SF->getNameStart(),
928 // If we found a global with the same name in the dest module, but it has
929 // internal linkage, we are really not doing any linkage here.
930 if (DGV && DGV->hasLocalLinkage())
933 // If types don't agree due to opaque types, try to resolve them.
934 if (DGV && DGV->getType() != SF->getType())
935 RecursiveResolveTypes(SF->getType(), DGV->getType());
937 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage;
938 bool LinkFromSrc = false;
939 if (GetLinkageResult(DGV, SF, NewLinkage, LinkFromSrc, Err))
942 // If there is no linkage to be performed, just bring over SF without
945 // Function does not already exist, simply insert an function signature
946 // identical to SF into the dest module.
947 Function *NewDF = Function::Create(SF->getFunctionType(),
949 SF->getName(), Dest);
950 CopyGVAttributes(NewDF, SF);
952 // If the LLVM runtime renamed the function, but it is an externally
953 // visible symbol, DF must be an existing function with internal linkage.
955 if (!NewDF->hasLocalLinkage() && NewDF->getName() != SF->getName())
956 ForceRenaming(NewDF, SF->getName());
958 // ... and remember this mapping...
959 ValueMap[SF] = NewDF;
963 // If the visibilities of the symbols disagree and the destination is a
964 // prototype, take the visibility of its input.
965 if (DGV->isDeclaration())
966 DGV->setVisibility(SF->getVisibility());
969 if (isa<GlobalAlias>(DGV))
970 return Error(Err, "Function-Alias Collision on '" + SF->getName() +
971 "': symbol multiple defined");
973 // We have a definition of the same name but different type in the
974 // source module. Copy the prototype to the destination and replace
975 // uses of the destination's prototype with the new prototype.
976 Function *NewDF = Function::Create(SF->getFunctionType(), NewLinkage,
977 SF->getName(), Dest);
978 CopyGVAttributes(NewDF, SF);
980 // Any uses of DF need to change to NewDF, with cast
981 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDF, DGV->getType()));
983 // DF will conflict with NewDF because they both had the same. We must
984 // erase this now so ForceRenaming doesn't assert because DF might
985 // not have internal linkage.
986 if (GlobalVariable *Var = dyn_cast<GlobalVariable>(DGV))
987 Var->eraseFromParent();
989 cast<Function>(DGV)->eraseFromParent();
991 // If the symbol table renamed the function, but it is an externally
992 // visible symbol, DF must be an existing function with internal
993 // linkage. Rename it.
994 if (NewDF->getName() != SF->getName() && !NewDF->hasLocalLinkage())
995 ForceRenaming(NewDF, SF->getName());
997 // Remember this mapping so uses in the source module get remapped
998 // later by RemapOperand.
999 ValueMap[SF] = NewDF;
1003 // Not "link from source", keep the one in the DestModule and remap the
1006 if (isa<GlobalAlias>(DGV)) {
1007 // The only valid mappings are:
1008 // - SF is external declaration, which is effectively a no-op.
1009 // - SF is weak, when we just need to throw SF out.
1010 if (!SF->isDeclaration() && !SF->isWeakForLinker())
1011 return Error(Err, "Function-Alias Collision on '" + SF->getName() +
1012 "': symbol multiple defined");
1015 // Set calculated linkage
1016 DGV->setLinkage(NewLinkage);
1018 // Make sure to remember this mapping.
1019 ValueMap[SF] = ConstantExpr::getBitCast(DGV, SF->getType());
1024 // LinkFunctionBody - Copy the source function over into the dest function and
1025 // fix up references to values. At this point we know that Dest is an external
1026 // function, and that Src is not.
1027 static bool LinkFunctionBody(Function *Dest, Function *Src,
1028 std::map<const Value*, Value*> &ValueMap,
1030 assert(Src && Dest && Dest->isDeclaration() && !Src->isDeclaration());
1032 // Go through and convert function arguments over, remembering the mapping.
1033 Function::arg_iterator DI = Dest->arg_begin();
1034 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end();
1035 I != E; ++I, ++DI) {
1036 DI->setName(I->getName()); // Copy the name information over...
1038 // Add a mapping to our local map
1042 // Splice the body of the source function into the dest function.
1043 Dest->getBasicBlockList().splice(Dest->end(), Src->getBasicBlockList());
1045 // At this point, all of the instructions and values of the function are now
1046 // copied over. The only problem is that they are still referencing values in
1047 // the Source function as operands. Loop through all of the operands of the
1048 // functions and patch them up to point to the local versions...
1050 for (Function::iterator BB = Dest->begin(), BE = Dest->end(); BB != BE; ++BB)
1051 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
1052 for (Instruction::op_iterator OI = I->op_begin(), OE = I->op_end();
1054 if (!isa<Instruction>(*OI) && !isa<BasicBlock>(*OI))
1055 *OI = RemapOperand(*OI, ValueMap);
1057 // There is no need to map the arguments anymore.
1058 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end();
1066 // LinkFunctionBodies - Link in the function bodies that are defined in the
1067 // source module into the DestModule. This consists basically of copying the
1068 // function over and fixing up references to values.
1069 static bool LinkFunctionBodies(Module *Dest, Module *Src,
1070 std::map<const Value*, Value*> &ValueMap,
1073 // Loop over all of the functions in the src module, mapping them over as we
1075 for (Module::iterator SF = Src->begin(), E = Src->end(); SF != E; ++SF) {
1076 if (!SF->isDeclaration()) { // No body if function is external
1077 Function *DF = dyn_cast<Function>(ValueMap[SF]); // Destination function
1079 // DF not external SF external?
1080 if (DF && DF->isDeclaration())
1081 // Only provide the function body if there isn't one already.
1082 if (LinkFunctionBody(DF, SF, ValueMap, Err))
1089 // LinkAppendingVars - If there were any appending global variables, link them
1090 // together now. Return true on error.
1091 static bool LinkAppendingVars(Module *M,
1092 std::multimap<std::string, GlobalVariable *> &AppendingVars,
1093 std::string *ErrorMsg) {
1094 if (AppendingVars.empty()) return false; // Nothing to do.
1096 // Loop over the multimap of appending vars, processing any variables with the
1097 // same name, forming a new appending global variable with both of the
1098 // initializers merged together, then rewrite references to the old variables
1100 std::vector<Constant*> Inits;
1101 while (AppendingVars.size() > 1) {
1102 // Get the first two elements in the map...
1103 std::multimap<std::string,
1104 GlobalVariable*>::iterator Second = AppendingVars.begin(), First=Second++;
1106 // If the first two elements are for different names, there is no pair...
1107 // Otherwise there is a pair, so link them together...
1108 if (First->first == Second->first) {
1109 GlobalVariable *G1 = First->second, *G2 = Second->second;
1110 const ArrayType *T1 = cast<ArrayType>(G1->getType()->getElementType());
1111 const ArrayType *T2 = cast<ArrayType>(G2->getType()->getElementType());
1113 // Check to see that they two arrays agree on type...
1114 if (T1->getElementType() != T2->getElementType())
1115 return Error(ErrorMsg,
1116 "Appending variables with different element types need to be linked!");
1117 if (G1->isConstant() != G2->isConstant())
1118 return Error(ErrorMsg,
1119 "Appending variables linked with different const'ness!");
1121 if (G1->getAlignment() != G2->getAlignment())
1122 return Error(ErrorMsg,
1123 "Appending variables with different alignment need to be linked!");
1125 if (G1->getVisibility() != G2->getVisibility())
1126 return Error(ErrorMsg,
1127 "Appending variables with different visibility need to be linked!");
1129 if (G1->getSection() != G2->getSection())
1130 return Error(ErrorMsg,
1131 "Appending variables with different section name need to be linked!");
1133 unsigned NewSize = T1->getNumElements() + T2->getNumElements();
1134 ArrayType *NewType = ArrayType::get(T1->getElementType(), NewSize);
1136 G1->setName(""); // Clear G1's name in case of a conflict!
1138 // Create the new global variable...
1139 GlobalVariable *NG =
1140 new GlobalVariable(NewType, G1->isConstant(), G1->getLinkage(),
1141 /*init*/0, First->first, M, G1->isThreadLocal(),
1142 G1->getType()->getAddressSpace());
1144 // Propagate alignment, visibility and section info.
1145 CopyGVAttributes(NG, G1);
1147 // Merge the initializer...
1148 Inits.reserve(NewSize);
1149 if (ConstantArray *I = dyn_cast<ConstantArray>(G1->getInitializer())) {
1150 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i)
1151 Inits.push_back(I->getOperand(i));
1153 assert(isa<ConstantAggregateZero>(G1->getInitializer()));
1154 Constant *CV = Constant::getNullValue(T1->getElementType());
1155 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i)
1156 Inits.push_back(CV);
1158 if (ConstantArray *I = dyn_cast<ConstantArray>(G2->getInitializer())) {
1159 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i)
1160 Inits.push_back(I->getOperand(i));
1162 assert(isa<ConstantAggregateZero>(G2->getInitializer()));
1163 Constant *CV = Constant::getNullValue(T2->getElementType());
1164 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i)
1165 Inits.push_back(CV);
1167 NG->setInitializer(ConstantArray::get(NewType, Inits));
1170 // Replace any uses of the two global variables with uses of the new
1173 // FIXME: This should rewrite simple/straight-forward uses such as
1174 // getelementptr instructions to not use the Cast!
1175 G1->replaceAllUsesWith(ConstantExpr::getBitCast(NG, G1->getType()));
1176 G2->replaceAllUsesWith(ConstantExpr::getBitCast(NG, G2->getType()));
1178 // Remove the two globals from the module now...
1179 M->getGlobalList().erase(G1);
1180 M->getGlobalList().erase(G2);
1182 // Put the new global into the AppendingVars map so that we can handle
1183 // linking of more than two vars...
1184 Second->second = NG;
1186 AppendingVars.erase(First);
1192 static bool ResolveAliases(Module *Dest) {
1193 for (Module::alias_iterator I = Dest->alias_begin(), E = Dest->alias_end();
1195 if (const GlobalValue *GV = I->resolveAliasedGlobal())
1196 if (GV != I && !GV->isDeclaration())
1197 I->replaceAllUsesWith(const_cast<GlobalValue*>(GV));
1202 // LinkModules - This function links two modules together, with the resulting
1203 // left module modified to be the composite of the two input modules. If an
1204 // error occurs, true is returned and ErrorMsg (if not null) is set to indicate
1205 // the problem. Upon failure, the Dest module could be in a modified state, and
1206 // shouldn't be relied on to be consistent.
1208 Linker::LinkModules(Module *Dest, Module *Src, std::string *ErrorMsg) {
1209 assert(Dest != 0 && "Invalid Destination module");
1210 assert(Src != 0 && "Invalid Source Module");
1212 if (Dest->getDataLayout().empty()) {
1213 if (!Src->getDataLayout().empty()) {
1214 Dest->setDataLayout(Src->getDataLayout());
1216 std::string DataLayout;
1218 if (Dest->getEndianness() == Module::AnyEndianness) {
1219 if (Src->getEndianness() == Module::BigEndian)
1220 DataLayout.append("E");
1221 else if (Src->getEndianness() == Module::LittleEndian)
1222 DataLayout.append("e");
1225 if (Dest->getPointerSize() == Module::AnyPointerSize) {
1226 if (Src->getPointerSize() == Module::Pointer64)
1227 DataLayout.append(DataLayout.length() == 0 ? "p:64:64" : "-p:64:64");
1228 else if (Src->getPointerSize() == Module::Pointer32)
1229 DataLayout.append(DataLayout.length() == 0 ? "p:32:32" : "-p:32:32");
1231 Dest->setDataLayout(DataLayout);
1235 // Copy the target triple from the source to dest if the dest's is empty.
1236 if (Dest->getTargetTriple().empty() && !Src->getTargetTriple().empty())
1237 Dest->setTargetTriple(Src->getTargetTriple());
1239 if (!Src->getDataLayout().empty() && !Dest->getDataLayout().empty() &&
1240 Src->getDataLayout() != Dest->getDataLayout())
1241 cerr << "WARNING: Linking two modules of different data layouts!\n";
1242 if (!Src->getTargetTriple().empty() &&
1243 Dest->getTargetTriple() != Src->getTargetTriple())
1244 cerr << "WARNING: Linking two modules of different target triples!\n";
1246 // Append the module inline asm string.
1247 if (!Src->getModuleInlineAsm().empty()) {
1248 if (Dest->getModuleInlineAsm().empty())
1249 Dest->setModuleInlineAsm(Src->getModuleInlineAsm());
1251 Dest->setModuleInlineAsm(Dest->getModuleInlineAsm()+"\n"+
1252 Src->getModuleInlineAsm());
1255 // Update the destination module's dependent libraries list with the libraries
1256 // from the source module. There's no opportunity for duplicates here as the
1257 // Module ensures that duplicate insertions are discarded.
1258 for (Module::lib_iterator SI = Src->lib_begin(), SE = Src->lib_end();
1260 Dest->addLibrary(*SI);
1262 // LinkTypes - Go through the symbol table of the Src module and see if any
1263 // types are named in the src module that are not named in the Dst module.
1264 // Make sure there are no type name conflicts.
1265 if (LinkTypes(Dest, Src, ErrorMsg))
1268 // ValueMap - Mapping of values from what they used to be in Src, to what they
1270 std::map<const Value*, Value*> ValueMap;
1272 // AppendingVars - Keep track of global variables in the destination module
1273 // with appending linkage. After the module is linked together, they are
1274 // appended and the module is rewritten.
1275 std::multimap<std::string, GlobalVariable *> AppendingVars;
1276 for (Module::global_iterator I = Dest->global_begin(), E = Dest->global_end();
1278 // Add all of the appending globals already in the Dest module to
1280 if (I->hasAppendingLinkage())
1281 AppendingVars.insert(std::make_pair(I->getName(), I));
1284 // Insert all of the globals in src into the Dest module... without linking
1285 // initializers (which could refer to functions not yet mapped over).
1286 if (LinkGlobals(Dest, Src, ValueMap, AppendingVars, ErrorMsg))
1289 // Link the functions together between the two modules, without doing function
1290 // bodies... this just adds external function prototypes to the Dest
1291 // function... We do this so that when we begin processing function bodies,
1292 // all of the global values that may be referenced are available in our
1294 if (LinkFunctionProtos(Dest, Src, ValueMap, ErrorMsg))
1297 // If there were any alias, link them now. We really need to do this now,
1298 // because all of the aliases that may be referenced need to be available in
1300 if (LinkAlias(Dest, Src, ValueMap, ErrorMsg)) return true;
1302 // Update the initializers in the Dest module now that all globals that may
1303 // be referenced are in Dest.
1304 if (LinkGlobalInits(Dest, Src, ValueMap, ErrorMsg)) return true;
1306 // Link in the function bodies that are defined in the source module into the
1307 // DestModule. This consists basically of copying the function over and
1308 // fixing up references to values.
1309 if (LinkFunctionBodies(Dest, Src, ValueMap, ErrorMsg)) return true;
1311 // If there were any appending global variables, link them together now.
1312 if (LinkAppendingVars(Dest, AppendingVars, ErrorMsg)) return true;
1314 // Resolve all uses of aliases with aliasees
1315 if (ResolveAliases(Dest)) return true;
1317 // If the source library's module id is in the dependent library list of the
1318 // destination library, remove it since that module is now linked in.
1320 modId.set(Src->getModuleIdentifier());
1321 if (!modId.isEmpty())
1322 Dest->removeLibrary(modId.getBasename());