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 // ToStr - Simple wrapper function to convert a type to a string.
41 static std::string ToStr(const Type *Ty, const Module *M) {
42 std::ostringstream OS;
43 WriteTypeSymbolic(OS, Ty, M);
48 // Function: ResolveTypes()
51 // Attempt to link the two specified types together.
54 // DestTy - The type to which we wish to resolve.
55 // SrcTy - The original type which we want to resolve.
58 // DestST - The symbol table in which the new type should be placed.
61 // true - There is an error and the types cannot yet be linked.
64 static bool ResolveTypes(const Type *DestTy, const Type *SrcTy) {
65 if (DestTy == SrcTy) return false; // If already equal, noop
66 assert(DestTy && SrcTy && "Can't handle null types");
68 if (const OpaqueType *OT = dyn_cast<OpaqueType>(DestTy)) {
69 // Type _is_ in module, just opaque...
70 const_cast<OpaqueType*>(OT)->refineAbstractTypeTo(SrcTy);
71 } else if (const OpaqueType *OT = dyn_cast<OpaqueType>(SrcTy)) {
72 const_cast<OpaqueType*>(OT)->refineAbstractTypeTo(DestTy);
74 return true; // Cannot link types... not-equal and neither is opaque.
79 /// LinkerTypeMap - This implements a map of types that is stable
80 /// even if types are resolved/refined to other types. This is not a general
81 /// purpose map, it is specific to the linker's use.
83 class LinkerTypeMap : public AbstractTypeUser {
84 typedef DenseMap<const Type*, PATypeHolder> TheMapTy;
87 LinkerTypeMap(const LinkerTypeMap&); // DO NOT IMPLEMENT
88 void operator=(const LinkerTypeMap&); // DO NOT IMPLEMENT
92 for (DenseMap<const Type*, PATypeHolder>::iterator I = TheMap.begin(),
93 E = TheMap.end(); I != E; ++I)
94 I->first->removeAbstractTypeUser(this);
97 /// lookup - Return the value for the specified type or null if it doesn't
99 const Type *lookup(const Type *Ty) const {
100 TheMapTy::const_iterator I = TheMap.find(Ty);
101 if (I != TheMap.end()) return I->second;
105 /// erase - Remove the specified type, returning true if it was in the set.
106 bool erase(const Type *Ty) {
107 if (!TheMap.erase(Ty))
109 if (Ty->isAbstract())
110 Ty->removeAbstractTypeUser(this);
114 /// insert - This returns true if the pointer was new to the set, false if it
115 /// was already in the set.
116 bool insert(const Type *Src, const Type *Dst) {
117 if (!TheMap.insert(std::make_pair(Src, PATypeHolder(Dst))).second)
118 return false; // Already in map.
119 if (Src->isAbstract())
120 Src->addAbstractTypeUser(this);
125 /// refineAbstractType - The callback method invoked when an abstract type is
126 /// resolved to another type. An object must override this method to update
127 /// its internal state to reference NewType instead of OldType.
129 virtual void refineAbstractType(const DerivedType *OldTy,
131 TheMapTy::iterator I = TheMap.find(OldTy);
132 const Type *DstTy = I->second;
135 if (OldTy->isAbstract())
136 OldTy->removeAbstractTypeUser(this);
138 // Don't reinsert into the map if the key is concrete now.
139 if (NewTy->isAbstract())
140 insert(NewTy, DstTy);
143 /// The other case which AbstractTypeUsers must be aware of is when a type
144 /// makes the transition from being abstract (where it has clients on it's
145 /// AbstractTypeUsers list) to concrete (where it does not). This method
146 /// notifies ATU's when this occurs for a type.
147 virtual void typeBecameConcrete(const DerivedType *AbsTy) {
149 AbsTy->removeAbstractTypeUser(this);
153 virtual void dump() const {
154 cerr << "AbstractTypeSet!\n";
160 // RecursiveResolveTypes - This is just like ResolveTypes, except that it
161 // recurses down into derived types, merging the used types if the parent types
163 static bool RecursiveResolveTypesI(const Type *DstTy, const Type *SrcTy,
164 LinkerTypeMap &Pointers) {
165 if (DstTy == SrcTy) return false; // If already equal, noop
167 // If we found our opaque type, resolve it now!
168 if (isa<OpaqueType>(DstTy) || isa<OpaqueType>(SrcTy))
169 return ResolveTypes(DstTy, SrcTy);
171 // Two types cannot be resolved together if they are of different primitive
172 // type. For example, we cannot resolve an int to a float.
173 if (DstTy->getTypeID() != SrcTy->getTypeID()) return true;
175 // If neither type is abstract, then they really are just different types.
176 if (!DstTy->isAbstract() && !SrcTy->isAbstract())
179 // Otherwise, resolve the used type used by this derived type...
180 switch (DstTy->getTypeID()) {
183 case Type::FunctionTyID: {
184 const FunctionType *DstFT = cast<FunctionType>(DstTy);
185 const FunctionType *SrcFT = cast<FunctionType>(SrcTy);
186 if (DstFT->isVarArg() != SrcFT->isVarArg() ||
187 DstFT->getNumContainedTypes() != SrcFT->getNumContainedTypes())
190 // Use TypeHolder's so recursive resolution won't break us.
191 PATypeHolder ST(SrcFT), DT(DstFT);
192 for (unsigned i = 0, e = DstFT->getNumContainedTypes(); i != e; ++i) {
193 const Type *SE = ST->getContainedType(i), *DE = DT->getContainedType(i);
194 if (SE != DE && RecursiveResolveTypesI(DE, SE, Pointers))
199 case Type::StructTyID: {
200 const StructType *DstST = cast<StructType>(DstTy);
201 const StructType *SrcST = cast<StructType>(SrcTy);
202 if (DstST->getNumContainedTypes() != SrcST->getNumContainedTypes())
205 PATypeHolder ST(SrcST), DT(DstST);
206 for (unsigned i = 0, e = DstST->getNumContainedTypes(); i != e; ++i) {
207 const Type *SE = ST->getContainedType(i), *DE = DT->getContainedType(i);
208 if (SE != DE && RecursiveResolveTypesI(DE, SE, Pointers))
213 case Type::ArrayTyID: {
214 const ArrayType *DAT = cast<ArrayType>(DstTy);
215 const ArrayType *SAT = cast<ArrayType>(SrcTy);
216 if (DAT->getNumElements() != SAT->getNumElements()) return true;
217 return RecursiveResolveTypesI(DAT->getElementType(), SAT->getElementType(),
220 case Type::VectorTyID: {
221 const VectorType *DVT = cast<VectorType>(DstTy);
222 const VectorType *SVT = cast<VectorType>(SrcTy);
223 if (DVT->getNumElements() != SVT->getNumElements()) return true;
224 return RecursiveResolveTypesI(DVT->getElementType(), SVT->getElementType(),
227 case Type::PointerTyID: {
228 const PointerType *DstPT = cast<PointerType>(DstTy);
229 const PointerType *SrcPT = cast<PointerType>(SrcTy);
231 if (DstPT->getAddressSpace() != SrcPT->getAddressSpace())
234 // If this is a pointer type, check to see if we have already seen it. If
235 // so, we are in a recursive branch. Cut off the search now. We cannot use
236 // an associative container for this search, because the type pointers (keys
237 // in the container) change whenever types get resolved.
238 if (SrcPT->isAbstract())
239 if (const Type *ExistingDestTy = Pointers.lookup(SrcPT))
240 return ExistingDestTy != DstPT;
242 if (DstPT->isAbstract())
243 if (const Type *ExistingSrcTy = Pointers.lookup(DstPT))
244 return ExistingSrcTy != SrcPT;
245 // Otherwise, add the current pointers to the vector to stop recursion on
247 if (DstPT->isAbstract())
248 Pointers.insert(DstPT, SrcPT);
249 if (SrcPT->isAbstract())
250 Pointers.insert(SrcPT, DstPT);
252 return RecursiveResolveTypesI(DstPT->getElementType(),
253 SrcPT->getElementType(), Pointers);
258 static bool RecursiveResolveTypes(const Type *DestTy, const Type *SrcTy) {
259 LinkerTypeMap PointerTypes;
260 return RecursiveResolveTypesI(DestTy, SrcTy, PointerTypes);
264 // LinkTypes - Go through the symbol table of the Src module and see if any
265 // types are named in the src module that are not named in the Dst module.
266 // Make sure there are no type name conflicts.
267 static bool LinkTypes(Module *Dest, const Module *Src, std::string *Err) {
268 TypeSymbolTable *DestST = &Dest->getTypeSymbolTable();
269 const TypeSymbolTable *SrcST = &Src->getTypeSymbolTable();
271 // Look for a type plane for Type's...
272 TypeSymbolTable::const_iterator TI = SrcST->begin();
273 TypeSymbolTable::const_iterator TE = SrcST->end();
274 if (TI == TE) return false; // No named types, do nothing.
276 // Some types cannot be resolved immediately because they depend on other
277 // types being resolved to each other first. This contains a list of types we
278 // are waiting to recheck.
279 std::vector<std::string> DelayedTypesToResolve;
281 for ( ; TI != TE; ++TI ) {
282 const std::string &Name = TI->first;
283 const Type *RHS = TI->second;
285 // Check to see if this type name is already in the dest module.
286 Type *Entry = DestST->lookup(Name);
288 // If the name is just in the source module, bring it over to the dest.
291 DestST->insert(Name, const_cast<Type*>(RHS));
292 } else if (ResolveTypes(Entry, RHS)) {
293 // They look different, save the types 'till later to resolve.
294 DelayedTypesToResolve.push_back(Name);
298 // Iteratively resolve types while we can...
299 while (!DelayedTypesToResolve.empty()) {
300 // Loop over all of the types, attempting to resolve them if possible...
301 unsigned OldSize = DelayedTypesToResolve.size();
303 // Try direct resolution by name...
304 for (unsigned i = 0; i != DelayedTypesToResolve.size(); ++i) {
305 const std::string &Name = DelayedTypesToResolve[i];
306 Type *T1 = SrcST->lookup(Name);
307 Type *T2 = DestST->lookup(Name);
308 if (!ResolveTypes(T2, T1)) {
309 // We are making progress!
310 DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i);
315 // Did we not eliminate any types?
316 if (DelayedTypesToResolve.size() == OldSize) {
317 // Attempt to resolve subelements of types. This allows us to merge these
318 // two types: { int* } and { opaque* }
319 for (unsigned i = 0, e = DelayedTypesToResolve.size(); i != e; ++i) {
320 const std::string &Name = DelayedTypesToResolve[i];
321 if (!RecursiveResolveTypes(SrcST->lookup(Name), DestST->lookup(Name))) {
322 // We are making progress!
323 DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i);
325 // Go back to the main loop, perhaps we can resolve directly by name
331 // If we STILL cannot resolve the types, then there is something wrong.
332 if (DelayedTypesToResolve.size() == OldSize) {
333 // Remove the symbol name from the destination.
334 DelayedTypesToResolve.pop_back();
343 static void PrintMap(const std::map<const Value*, Value*> &M) {
344 for (std::map<const Value*, Value*>::const_iterator I = M.begin(), E =M.end();
346 cerr << " Fr: " << (void*)I->first << " ";
348 cerr << " To: " << (void*)I->second << " ";
355 // RemapOperand - Use ValueMap to convert constants from one module to another.
356 static Value *RemapOperand(const Value *In,
357 std::map<const Value*, Value*> &ValueMap) {
358 std::map<const Value*,Value*>::const_iterator I = ValueMap.find(In);
359 if (I != ValueMap.end())
362 // Check to see if it's a constant that we are interested in transforming.
364 if (const Constant *CPV = dyn_cast<Constant>(In)) {
365 if ((!isa<DerivedType>(CPV->getType()) && !isa<ConstantExpr>(CPV)) ||
366 isa<ConstantInt>(CPV) || isa<ConstantAggregateZero>(CPV))
367 return const_cast<Constant*>(CPV); // Simple constants stay identical.
369 if (const ConstantArray *CPA = dyn_cast<ConstantArray>(CPV)) {
370 std::vector<Constant*> Operands(CPA->getNumOperands());
371 for (unsigned i = 0, e = CPA->getNumOperands(); i != e; ++i)
372 Operands[i] =cast<Constant>(RemapOperand(CPA->getOperand(i), ValueMap));
373 Result = ConstantArray::get(cast<ArrayType>(CPA->getType()), Operands);
374 } else if (const ConstantStruct *CPS = dyn_cast<ConstantStruct>(CPV)) {
375 std::vector<Constant*> Operands(CPS->getNumOperands());
376 for (unsigned i = 0, e = CPS->getNumOperands(); i != e; ++i)
377 Operands[i] =cast<Constant>(RemapOperand(CPS->getOperand(i), ValueMap));
378 Result = ConstantStruct::get(cast<StructType>(CPS->getType()), Operands);
379 } else if (isa<ConstantPointerNull>(CPV) || isa<UndefValue>(CPV)) {
380 Result = const_cast<Constant*>(CPV);
381 } else if (const ConstantVector *CP = dyn_cast<ConstantVector>(CPV)) {
382 std::vector<Constant*> Operands(CP->getNumOperands());
383 for (unsigned i = 0, e = CP->getNumOperands(); i != e; ++i)
384 Operands[i] = cast<Constant>(RemapOperand(CP->getOperand(i), ValueMap));
385 Result = ConstantVector::get(Operands);
386 } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CPV)) {
387 std::vector<Constant*> Ops;
388 for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i)
389 Ops.push_back(cast<Constant>(RemapOperand(CE->getOperand(i),ValueMap)));
390 Result = CE->getWithOperands(Ops);
391 } else if (isa<GlobalValue>(CPV)) {
392 assert(0 && "Unmapped global?");
394 assert(0 && "Unknown type of derived type constant value!");
396 } else if (isa<InlineAsm>(In)) {
397 Result = const_cast<Value*>(In);
400 // Cache the mapping in our local map structure
402 ValueMap[In] = Result;
407 cerr << "LinkModules ValueMap: \n";
410 cerr << "Couldn't remap value: " << (void*)In << " " << *In << "\n";
411 assert(0 && "Couldn't remap value!");
415 /// ForceRenaming - The LLVM SymbolTable class autorenames globals that conflict
416 /// in the symbol table. This is good for all clients except for us. Go
417 /// through the trouble to force this back.
418 static void ForceRenaming(GlobalValue *GV, const std::string &Name) {
419 assert(GV->getName() != Name && "Can't force rename to self");
420 ValueSymbolTable &ST = GV->getParent()->getValueSymbolTable();
422 // If there is a conflict, rename the conflict.
423 if (GlobalValue *ConflictGV = cast_or_null<GlobalValue>(ST.lookup(Name))) {
424 assert(ConflictGV->hasInternalLinkage() &&
425 "Not conflicting with a static global, should link instead!");
426 GV->takeName(ConflictGV);
427 ConflictGV->setName(Name); // This will cause ConflictGV to get renamed
428 assert(ConflictGV->getName() != Name && "ForceRenaming didn't work");
430 GV->setName(Name); // Force the name back
434 /// CopyGVAttributes - copy additional attributes (those not needed to construct
435 /// a GlobalValue) from the SrcGV to the DestGV.
436 static void CopyGVAttributes(GlobalValue *DestGV, const GlobalValue *SrcGV) {
437 // Use the maximum alignment, rather than just copying the alignment of SrcGV.
438 unsigned Alignment = std::max(DestGV->getAlignment(), SrcGV->getAlignment());
439 DestGV->copyAttributesFrom(SrcGV);
440 DestGV->setAlignment(Alignment);
443 /// GetLinkageResult - This analyzes the two global values and determines what
444 /// the result will look like in the destination module. In particular, it
445 /// computes the resultant linkage type, computes whether the global in the
446 /// source should be copied over to the destination (replacing the existing
447 /// one), and computes whether this linkage is an error or not. It also performs
448 /// visibility checks: we cannot link together two symbols with different
450 static bool GetLinkageResult(GlobalValue *Dest, const GlobalValue *Src,
451 GlobalValue::LinkageTypes <, bool &LinkFromSrc,
453 assert((!Dest || !Src->hasInternalLinkage()) &&
454 "If Src has internal linkage, Dest shouldn't be set!");
456 // Linking something to nothing.
458 LT = Src->getLinkage();
459 } else if (Src->isDeclaration()) {
460 // If Src is external or if both Src & Dest are external.. Just link the
461 // external globals, we aren't adding anything.
462 if (Src->hasDLLImportLinkage()) {
463 // If one of GVs has DLLImport linkage, result should be dllimport'ed.
464 if (Dest->isDeclaration()) {
466 LT = Src->getLinkage();
468 } else if (Dest->hasExternalWeakLinkage()) {
469 //If the Dest is weak, use the source linkage
471 LT = Src->getLinkage();
474 LT = Dest->getLinkage();
476 } else if (Dest->isDeclaration() && !Dest->hasDLLImportLinkage()) {
477 // If Dest is external but Src is not:
479 LT = Src->getLinkage();
480 } else if (Src->hasAppendingLinkage() || Dest->hasAppendingLinkage()) {
481 if (Src->getLinkage() != Dest->getLinkage())
482 return Error(Err, "Linking globals named '" + Src->getName() +
483 "': can only link appending global with another appending global!");
484 LinkFromSrc = true; // Special cased.
485 LT = Src->getLinkage();
486 } else if (Src->isWeakForLinker()) {
487 // At this point we know that Dest has LinkOnce, External*, Weak, Common,
489 if ((Dest->hasLinkOnceLinkage() &&
490 (Src->hasWeakLinkage() || Src->hasCommonLinkage())) ||
491 Dest->hasExternalWeakLinkage()) {
493 LT = Src->getLinkage();
496 LT = Dest->getLinkage();
498 } else if (Dest->isWeakForLinker()) {
499 // At this point we know that Src has External* or DLL* linkage.
500 if (Src->hasExternalWeakLinkage()) {
502 LT = Dest->getLinkage();
505 LT = GlobalValue::ExternalLinkage;
508 assert((Dest->hasExternalLinkage() ||
509 Dest->hasDLLImportLinkage() ||
510 Dest->hasDLLExportLinkage() ||
511 Dest->hasExternalWeakLinkage()) &&
512 (Src->hasExternalLinkage() ||
513 Src->hasDLLImportLinkage() ||
514 Src->hasDLLExportLinkage() ||
515 Src->hasExternalWeakLinkage()) &&
516 "Unexpected linkage type!");
517 return Error(Err, "Linking globals named '" + Src->getName() +
518 "': symbol multiply defined!");
522 if (Dest && Src->getVisibility() != Dest->getVisibility())
523 if (!Src->isDeclaration() && !Dest->isDeclaration())
524 return Error(Err, "Linking globals named '" + Src->getName() +
525 "': symbols have different visibilities!");
529 // LinkGlobals - Loop through the global variables in the src module and merge
530 // them into the dest module.
531 static bool LinkGlobals(Module *Dest, const Module *Src,
532 std::map<const Value*, Value*> &ValueMap,
533 std::multimap<std::string, GlobalVariable *> &AppendingVars,
535 // Loop over all of the globals in the src module, mapping them over as we go
536 for (Module::const_global_iterator I = Src->global_begin(), E = Src->global_end();
538 const GlobalVariable *SGV = I;
539 GlobalValue *DGV = 0;
541 // Check to see if may have to link the global with the global
542 if (SGV->hasName() && !SGV->hasInternalLinkage()) {
543 DGV = Dest->getGlobalVariable(SGV->getName());
544 if (DGV && DGV->getType() != SGV->getType())
545 // If types don't agree due to opaque types, try to resolve them.
546 RecursiveResolveTypes(SGV->getType(), DGV->getType());
549 // Check to see if may have to link the global with the alias
550 if (!DGV && SGV->hasName() && !SGV->hasInternalLinkage()) {
551 DGV = Dest->getNamedAlias(SGV->getName());
552 if (DGV && DGV->getType() != SGV->getType())
553 // If types don't agree due to opaque types, try to resolve them.
554 RecursiveResolveTypes(SGV->getType(), DGV->getType());
557 if (DGV && DGV->hasInternalLinkage())
560 assert((SGV->hasInitializer() || SGV->hasExternalWeakLinkage() ||
561 SGV->hasExternalLinkage() || SGV->hasDLLImportLinkage()) &&
562 "Global must either be external or have an initializer!");
564 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage;
565 bool LinkFromSrc = false;
566 if (GetLinkageResult(DGV, SGV, NewLinkage, LinkFromSrc, Err))
570 // No linking to be performed, simply create an identical version of the
571 // symbol over in the dest module... the initializer will be filled in
572 // later by LinkGlobalInits...
573 GlobalVariable *NewDGV =
574 new GlobalVariable(SGV->getType()->getElementType(),
575 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
576 SGV->getName(), Dest, false,
577 SGV->getType()->getAddressSpace());
578 // Propagate alignment, visibility and section info.
579 CopyGVAttributes(NewDGV, SGV);
581 // If the LLVM runtime renamed the global, but it is an externally visible
582 // symbol, DGV must be an existing global with internal linkage. Rename
584 if (NewDGV->getName() != SGV->getName() && !NewDGV->hasInternalLinkage())
585 ForceRenaming(NewDGV, SGV->getName());
587 // Make sure to remember this mapping...
588 ValueMap[SGV] = NewDGV;
590 if (SGV->hasAppendingLinkage())
591 // Keep track that this is an appending variable...
592 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV));
593 } else 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));
614 } else if (GlobalAlias *DGA = dyn_cast<GlobalAlias>(DGV)) {
615 // SGV is global, but DGV is alias. The only valid mapping is when SGV is
616 // external declaration, which is effectively a no-op. Also make sure
617 // linkage calculation was correct.
618 if (SGV->isDeclaration() && !LinkFromSrc) {
619 // Make sure to remember this mapping...
622 return Error(Err, "Global-Alias Collision on '" + SGV->getName() +
623 "': symbol multiple defined");
624 } else if (GlobalVariable *DGVar = dyn_cast<GlobalVariable>(DGV)) {
625 // Otherwise, perform the global-global mapping as instructed by
628 // Propagate alignment, section, and visibility info.
629 CopyGVAttributes(DGVar, SGV);
631 // If the types don't match, and if we are to link from the source, nuke
632 // DGV and create a new one of the appropriate type.
633 if (SGV->getType() != DGVar->getType()) {
634 GlobalVariable *NewDGV =
635 new GlobalVariable(SGV->getType()->getElementType(),
636 DGVar->isConstant(), DGVar->getLinkage(),
637 /*init*/0, DGVar->getName(), Dest, false,
638 SGV->getType()->getAddressSpace());
639 CopyGVAttributes(NewDGV, DGVar);
640 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDGV,
642 // DGVar will conflict with NewDGV because they both had the same
643 // name. We must erase this now so ForceRenaming doesn't assert
644 // because DGV might not have internal linkage.
645 DGVar->eraseFromParent();
647 // If the symbol table renamed the global, but it is an externally
648 // visible symbol, DGV must be an existing global with internal
649 // linkage. Rename it.
650 if (NewDGV->getName() != SGV->getName() &&
651 !NewDGV->hasInternalLinkage())
652 ForceRenaming(NewDGV, SGV->getName());
657 // Inherit const as appropriate
658 DGVar->setConstant(SGV->isConstant());
660 // Set initializer to zero, so we can link the stuff later
661 DGVar->setInitializer(0);
663 // Special case for const propagation
664 if (DGVar->isDeclaration() && SGV->isConstant() && !DGVar->isConstant())
665 DGVar->setConstant(true);
668 // Set calculated linkage
669 DGVar->setLinkage(NewLinkage);
671 // Make sure to remember this mapping...
672 ValueMap[SGV] = ConstantExpr::getBitCast(DGVar, SGV->getType());
678 static GlobalValue::LinkageTypes
679 CalculateAliasLinkage(const GlobalValue *SGV, const GlobalValue *DGV) {
680 if (SGV->hasExternalLinkage() || DGV->hasExternalLinkage())
681 return GlobalValue::ExternalLinkage;
682 else if (SGV->hasWeakLinkage() || DGV->hasWeakLinkage())
683 return GlobalValue::WeakLinkage;
685 assert(SGV->hasInternalLinkage() && DGV->hasInternalLinkage() &&
686 "Unexpected linkage type");
687 return GlobalValue::InternalLinkage;
691 // LinkAlias - Loop through the alias in the src module and link them into the
692 // dest module. We're assuming, that all functions/global variables were already
694 static bool LinkAlias(Module *Dest, const Module *Src,
695 std::map<const Value*, Value*> &ValueMap,
697 // Loop over all alias in the src module
698 for (Module::const_alias_iterator I = Src->alias_begin(),
699 E = Src->alias_end(); I != E; ++I) {
700 const GlobalAlias *SGA = I;
701 const GlobalValue *SAliasee = SGA->getAliasedGlobal();
702 GlobalAlias *NewGA = NULL;
704 // Globals were already linked, thus we can just query ValueMap for variant
705 // of SAliasee in Dest.
706 std::map<const Value*,Value*>::const_iterator VMI = ValueMap.find(SAliasee);
707 assert(VMI != ValueMap.end() && "Aliasee not linked");
708 GlobalValue* DAliasee = cast<GlobalValue>(VMI->second);
709 GlobalValue* DGV = NULL;
711 // Try to find something 'similar' to SGA in destination module.
712 if (!DGV && !SGA->hasInternalLinkage()) {
713 DGV = Dest->getNamedAlias(SGA->getName());
715 // If types don't agree due to opaque types, try to resolve them.
716 if (DGV && DGV->getType() != SGA->getType())
717 RecursiveResolveTypes(SGA->getType(), DGV->getType());
720 if (!DGV && !SGA->hasInternalLinkage()) {
721 DGV = Dest->getGlobalVariable(SGA->getName());
723 // If types don't agree due to opaque types, try to resolve them.
724 if (DGV && DGV->getType() != SGA->getType())
725 RecursiveResolveTypes(SGA->getType(), DGV->getType());
728 if (!DGV && !SGA->hasInternalLinkage()) {
729 DGV = Dest->getFunction(SGA->getName());
731 // If types don't agree due to opaque types, try to resolve them.
732 if (DGV && DGV->getType() != SGA->getType())
733 RecursiveResolveTypes(SGA->getType(), DGV->getType());
736 // No linking to be performed on internal stuff.
737 if (DGV && DGV->hasInternalLinkage())
740 if (GlobalAlias *DGA = dyn_cast_or_null<GlobalAlias>(DGV)) {
741 // Types are known to be the same, check whether aliasees equal. As
742 // globals are already linked we just need query ValueMap to find the
744 if (DAliasee == DGA->getAliasedGlobal()) {
745 // This is just two copies of the same alias. Propagate linkage, if
747 DGA->setLinkage(CalculateAliasLinkage(SGA, DGA));
750 // Proceed to 'common' steps
752 return Error(Err, "Alias Collision on '" + SGA->getName()+
753 "': aliases have different aliasees");
754 } else if (GlobalVariable *DGVar = dyn_cast_or_null<GlobalVariable>(DGV)) {
755 // The only allowed way is to link alias with external declaration or weak
757 if (DGVar->isDeclaration() || DGVar->isWeakForLinker()) {
758 // But only if aliasee is global too...
759 if (!isa<GlobalVariable>(DAliasee))
760 return Error(Err, "Global-Alias Collision on '" + SGA->getName() +
761 "': aliasee is not global variable");
763 NewGA = new GlobalAlias(SGA->getType(), SGA->getLinkage(),
764 SGA->getName(), DAliasee, Dest);
765 CopyGVAttributes(NewGA, SGA);
767 // Any uses of DGV need to change to NewGA, with cast, if needed.
768 if (SGA->getType() != DGVar->getType())
769 DGVar->replaceAllUsesWith(ConstantExpr::getBitCast(NewGA,
772 DGVar->replaceAllUsesWith(NewGA);
774 // DGVar will conflict with NewGA because they both had the same
775 // name. We must erase this now so ForceRenaming doesn't assert
776 // because DGV might not have internal linkage.
777 DGVar->eraseFromParent();
779 // Proceed to 'common' steps
781 return Error(Err, "Global-Alias Collision on '" + SGA->getName() +
782 "': symbol multiple defined");
783 } else if (Function *DF = dyn_cast_or_null<Function>(DGV)) {
784 // The only allowed way is to link alias with external declaration or weak
786 if (DF->isDeclaration() || DF->isWeakForLinker()) {
787 // But only if aliasee is function too...
788 if (!isa<Function>(DAliasee))
789 return Error(Err, "Function-Alias Collision on '" + SGA->getName() +
790 "': aliasee is not function");
792 NewGA = new GlobalAlias(SGA->getType(), SGA->getLinkage(),
793 SGA->getName(), DAliasee, Dest);
794 CopyGVAttributes(NewGA, SGA);
796 // Any uses of DF need to change to NewGA, with cast, if needed.
797 if (SGA->getType() != DF->getType())
798 DF->replaceAllUsesWith(ConstantExpr::getBitCast(NewGA,
801 DF->replaceAllUsesWith(NewGA);
803 // DF will conflict with NewGA because they both had the same
804 // name. We must erase this now so ForceRenaming doesn't assert
805 // because DF might not have internal linkage.
806 DF->eraseFromParent();
808 // Proceed to 'common' steps
810 return Error(Err, "Function-Alias Collision on '" + SGA->getName() +
811 "': symbol multiple defined");
813 // No linking to be performed, simply create an identical version of the
814 // alias over in the dest module...
816 NewGA = new GlobalAlias(SGA->getType(), SGA->getLinkage(),
817 SGA->getName(), DAliasee, Dest);
818 CopyGVAttributes(NewGA, SGA);
820 // Proceed to 'common' steps
823 assert(NewGA && "No alias was created in destination module!");
825 // If the symbol table renamed the alias, but it is an externally visible
826 // symbol, DGA must be an global value with internal linkage. Rename it.
827 if (NewGA->getName() != SGA->getName() &&
828 !NewGA->hasInternalLinkage())
829 ForceRenaming(NewGA, SGA->getName());
831 // Remember this mapping so uses in the source module get remapped
832 // later by RemapOperand.
833 ValueMap[SGA] = NewGA;
840 // LinkGlobalInits - Update the initializers in the Dest module now that all
841 // globals that may be referenced are in Dest.
842 static bool LinkGlobalInits(Module *Dest, const Module *Src,
843 std::map<const Value*, Value*> &ValueMap,
846 // Loop over all of the globals in the src module, mapping them over as we go
847 for (Module::const_global_iterator I = Src->global_begin(),
848 E = Src->global_end(); I != E; ++I) {
849 const GlobalVariable *SGV = I;
851 if (SGV->hasInitializer()) { // Only process initialized GV's
852 // Figure out what the initializer looks like in the dest module...
854 cast<Constant>(RemapOperand(SGV->getInitializer(), ValueMap));
856 GlobalVariable *DGV =
857 cast<GlobalVariable>(ValueMap[SGV]->stripPointerCasts());
858 if (DGV->hasInitializer()) {
859 if (SGV->hasExternalLinkage()) {
860 if (DGV->getInitializer() != SInit)
861 return Error(Err, "Global Variable Collision on '" + SGV->getName() +
862 "': global variables have different initializers");
863 } else if (DGV->isWeakForLinker()) {
864 // Nothing is required, mapped values will take the new global
866 } else if (SGV->isWeakForLinker()) {
867 // Nothing is required, mapped values will take the new global
869 } else if (DGV->hasAppendingLinkage()) {
870 assert(0 && "Appending linkage unimplemented!");
872 assert(0 && "Unknown linkage!");
875 // Copy the initializer over now...
876 DGV->setInitializer(SInit);
883 // LinkFunctionProtos - Link the functions together between the two modules,
884 // without doing function bodies... this just adds external function prototypes
885 // to the Dest function...
887 static bool LinkFunctionProtos(Module *Dest, const Module *Src,
888 std::map<const Value*, Value*> &ValueMap,
890 // Loop over all of the functions in the src module, mapping them over
891 for (Module::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) {
892 const Function *SF = I; // SrcFunction
894 GlobalValue *DGV = 0;
897 // If this function is internal or has no name, it doesn't participate in
899 if (SF->hasName() && !SF->hasInternalLinkage()) {
900 // Check to see if may have to link the function.
901 DGV = Dest->getFunction(SF->getName());
904 // Check to see if may have to link the function with the alias
905 if (!DGV && SF->hasName() && !SF->hasInternalLinkage()) {
906 DGV = Dest->getNamedAlias(SF->getName());
907 if (DGV && DGV->getType() != SF->getType())
908 // If types don't agree due to opaque types, try to resolve them.
909 RecursiveResolveTypes(SF->getType(), DGV->getType());
912 if (DGV && DGV->hasInternalLinkage())
915 // If there is no linkage to be performed, just bring over SF without
918 // Function does not already exist, simply insert an function signature
919 // identical to SF into the dest module.
920 Function *NewDF = Function::Create(SF->getFunctionType(),
922 SF->getName(), Dest);
923 CopyGVAttributes(NewDF, SF);
925 // If the LLVM runtime renamed the function, but it is an externally
926 // visible symbol, DF must be an existing function with internal linkage.
928 if (!NewDF->hasInternalLinkage() && NewDF->getName() != SF->getName())
929 ForceRenaming(NewDF, SF->getName());
931 // ... and remember this mapping...
932 ValueMap[SF] = NewDF;
934 } else if (GlobalAlias *DGA = dyn_cast<GlobalAlias>(DGV)) {
935 // SF is function, but DF is alias.
936 // The only valid mappings are:
937 // - SF is external declaration, which is effectively a no-op.
938 // - SF is weak, when we just need to throw SF out.
939 if (!SF->isDeclaration() && !SF->isWeakForLinker())
940 return Error(Err, "Function-Alias Collision on '" + SF->getName() +
941 "': symbol multiple defined");
943 // Make sure to remember this mapping...
944 ValueMap[SF] = ConstantExpr::getBitCast(DGA, SF->getType());
948 Function* DF = cast<Function>(DGV);
949 // If types don't agree because of opaque, try to resolve them.
950 if (SF->getType() != DF->getType())
951 RecursiveResolveTypes(SF->getType(), DF->getType());
953 // Check visibility, merging if a definition overrides a prototype.
954 if (SF->getVisibility() != DF->getVisibility()) {
955 // If one is a prototype, ignore its visibility. Prototypes are always
956 // overridden by the definition.
957 if (!SF->isDeclaration() && !DF->isDeclaration())
958 return Error(Err, "Linking functions named '" + SF->getName() +
959 "': symbols have different visibilities!");
961 // Otherwise, replace the visibility of DF if DF is a prototype.
962 if (DF->isDeclaration())
963 DF->setVisibility(SF->getVisibility());
966 if (DF->getType() != SF->getType()) {
967 if (DF->isDeclaration() && !SF->isDeclaration()) {
968 // We have a definition of the same name but different type in the
969 // source module. Copy the prototype to the destination and replace
970 // uses of the destination's prototype with the new prototype.
971 Function *NewDF = Function::Create(SF->getFunctionType(),
973 SF->getName(), Dest);
974 CopyGVAttributes(NewDF, SF);
976 // Any uses of DF need to change to NewDF, with cast
977 DF->replaceAllUsesWith(ConstantExpr::getBitCast(NewDF, DF->getType()));
979 // DF will conflict with NewDF because they both had the same. We must
980 // erase this now so ForceRenaming doesn't assert because DF might
981 // not have internal linkage.
982 DF->eraseFromParent();
984 // If the symbol table renamed the function, but it is an externally
985 // visible symbol, DF must be an existing function with internal
986 // linkage. Rename it.
987 if (NewDF->getName() != SF->getName() && !NewDF->hasInternalLinkage())
988 ForceRenaming(NewDF, SF->getName());
990 // Remember this mapping so uses in the source module get remapped
991 // later by RemapOperand.
992 ValueMap[SF] = NewDF;
995 // We have two functions of the same name but different type. Any use
996 // of the source must be mapped to the destination, with a cast.
997 MappedDF = ConstantExpr::getBitCast(DF, SF->getType());
1003 if (SF->isDeclaration()) {
1004 // If SF is a declaration or if both SF & DF are declarations, just link
1005 // the declarations, we aren't adding anything.
1006 if (SF->hasDLLImportLinkage()) {
1007 if (DF->isDeclaration()) {
1008 ValueMap[SF] = MappedDF;
1009 DF->setLinkage(SF->getLinkage());
1012 ValueMap[SF] = MappedDF;
1017 // If DF is external but SF is not, link the external functions, update
1018 // linkage qualifiers.
1019 if (DF->isDeclaration() && !DF->hasDLLImportLinkage()) {
1020 ValueMap.insert(std::make_pair(SF, MappedDF));
1021 DF->setLinkage(SF->getLinkage());
1025 // At this point we know that DF has LinkOnce, Weak, or External* linkage.
1026 if (SF->isWeakForLinker()) {
1027 ValueMap[SF] = MappedDF;
1029 // Linkonce+Weak = Weak
1030 // *+External Weak = *
1031 if ((DF->hasLinkOnceLinkage() &&
1032 (SF->hasWeakLinkage() || SF->hasCommonLinkage())) ||
1033 DF->hasExternalWeakLinkage())
1034 DF->setLinkage(SF->getLinkage());
1038 if (DF->isWeakForLinker()) {
1039 // At this point we know that SF has LinkOnce or External* linkage.
1040 ValueMap[SF] = MappedDF;
1042 // If the source function has stronger linkage than the destination,
1043 // its body and linkage should override ours.
1044 if (!SF->hasLinkOnceLinkage() && !SF->hasExternalWeakLinkage()) {
1045 // Don't inherit linkonce & external weak linkage.
1046 DF->setLinkage(SF->getLinkage());
1052 if (SF->getLinkage() != DF->getLinkage())
1053 return Error(Err, "Functions named '" + SF->getName() +
1054 "' have different linkage specifiers!");
1056 // The function is defined identically in both modules!
1057 if (SF->hasExternalLinkage())
1058 return Error(Err, "Function '" +
1059 ToStr(SF->getFunctionType(), Src) + "':\"" +
1060 SF->getName() + "\" - Function is already defined!");
1061 assert(0 && "Unknown linkage configuration found!");
1066 // LinkFunctionBody - Copy the source function over into the dest function and
1067 // fix up references to values. At this point we know that Dest is an external
1068 // function, and that Src is not.
1069 static bool LinkFunctionBody(Function *Dest, Function *Src,
1070 std::map<const Value*, Value*> &ValueMap,
1072 assert(Src && Dest && Dest->isDeclaration() && !Src->isDeclaration());
1074 // Go through and convert function arguments over, remembering the mapping.
1075 Function::arg_iterator DI = Dest->arg_begin();
1076 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end();
1077 I != E; ++I, ++DI) {
1078 DI->setName(I->getName()); // Copy the name information over...
1080 // Add a mapping to our local map
1084 // Splice the body of the source function into the dest function.
1085 Dest->getBasicBlockList().splice(Dest->end(), Src->getBasicBlockList());
1087 // At this point, all of the instructions and values of the function are now
1088 // copied over. The only problem is that they are still referencing values in
1089 // the Source function as operands. Loop through all of the operands of the
1090 // functions and patch them up to point to the local versions...
1092 for (Function::iterator BB = Dest->begin(), BE = Dest->end(); BB != BE; ++BB)
1093 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
1094 for (Instruction::op_iterator OI = I->op_begin(), OE = I->op_end();
1096 if (!isa<Instruction>(*OI) && !isa<BasicBlock>(*OI))
1097 *OI = RemapOperand(*OI, ValueMap);
1099 // There is no need to map the arguments anymore.
1100 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end();
1108 // LinkFunctionBodies - Link in the function bodies that are defined in the
1109 // source module into the DestModule. This consists basically of copying the
1110 // function over and fixing up references to values.
1111 static bool LinkFunctionBodies(Module *Dest, Module *Src,
1112 std::map<const Value*, Value*> &ValueMap,
1115 // Loop over all of the functions in the src module, mapping them over as we
1117 for (Module::iterator SF = Src->begin(), E = Src->end(); SF != E; ++SF) {
1118 if (!SF->isDeclaration()) { // No body if function is external
1119 Function *DF = dyn_cast<Function>(ValueMap[SF]); // Destination function
1121 // DF not external SF external?
1122 if (DF && DF->isDeclaration())
1123 // Only provide the function body if there isn't one already.
1124 if (LinkFunctionBody(DF, SF, ValueMap, Err))
1131 // LinkAppendingVars - If there were any appending global variables, link them
1132 // together now. Return true on error.
1133 static bool LinkAppendingVars(Module *M,
1134 std::multimap<std::string, GlobalVariable *> &AppendingVars,
1135 std::string *ErrorMsg) {
1136 if (AppendingVars.empty()) return false; // Nothing to do.
1138 // Loop over the multimap of appending vars, processing any variables with the
1139 // same name, forming a new appending global variable with both of the
1140 // initializers merged together, then rewrite references to the old variables
1142 std::vector<Constant*> Inits;
1143 while (AppendingVars.size() > 1) {
1144 // Get the first two elements in the map...
1145 std::multimap<std::string,
1146 GlobalVariable*>::iterator Second = AppendingVars.begin(), First=Second++;
1148 // If the first two elements are for different names, there is no pair...
1149 // Otherwise there is a pair, so link them together...
1150 if (First->first == Second->first) {
1151 GlobalVariable *G1 = First->second, *G2 = Second->second;
1152 const ArrayType *T1 = cast<ArrayType>(G1->getType()->getElementType());
1153 const ArrayType *T2 = cast<ArrayType>(G2->getType()->getElementType());
1155 // Check to see that they two arrays agree on type...
1156 if (T1->getElementType() != T2->getElementType())
1157 return Error(ErrorMsg,
1158 "Appending variables with different element types need to be linked!");
1159 if (G1->isConstant() != G2->isConstant())
1160 return Error(ErrorMsg,
1161 "Appending variables linked with different const'ness!");
1163 if (G1->getAlignment() != G2->getAlignment())
1164 return Error(ErrorMsg,
1165 "Appending variables with different alignment need to be linked!");
1167 if (G1->getVisibility() != G2->getVisibility())
1168 return Error(ErrorMsg,
1169 "Appending variables with different visibility need to be linked!");
1171 if (G1->getSection() != G2->getSection())
1172 return Error(ErrorMsg,
1173 "Appending variables with different section name need to be linked!");
1175 unsigned NewSize = T1->getNumElements() + T2->getNumElements();
1176 ArrayType *NewType = ArrayType::get(T1->getElementType(), NewSize);
1178 G1->setName(""); // Clear G1's name in case of a conflict!
1180 // Create the new global variable...
1181 GlobalVariable *NG =
1182 new GlobalVariable(NewType, G1->isConstant(), G1->getLinkage(),
1183 /*init*/0, First->first, M, G1->isThreadLocal(),
1184 G1->getType()->getAddressSpace());
1186 // Propagate alignment, visibility and section info.
1187 CopyGVAttributes(NG, G1);
1189 // Merge the initializer...
1190 Inits.reserve(NewSize);
1191 if (ConstantArray *I = dyn_cast<ConstantArray>(G1->getInitializer())) {
1192 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i)
1193 Inits.push_back(I->getOperand(i));
1195 assert(isa<ConstantAggregateZero>(G1->getInitializer()));
1196 Constant *CV = Constant::getNullValue(T1->getElementType());
1197 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i)
1198 Inits.push_back(CV);
1200 if (ConstantArray *I = dyn_cast<ConstantArray>(G2->getInitializer())) {
1201 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i)
1202 Inits.push_back(I->getOperand(i));
1204 assert(isa<ConstantAggregateZero>(G2->getInitializer()));
1205 Constant *CV = Constant::getNullValue(T2->getElementType());
1206 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i)
1207 Inits.push_back(CV);
1209 NG->setInitializer(ConstantArray::get(NewType, Inits));
1212 // Replace any uses of the two global variables with uses of the new
1215 // FIXME: This should rewrite simple/straight-forward uses such as
1216 // getelementptr instructions to not use the Cast!
1217 G1->replaceAllUsesWith(ConstantExpr::getBitCast(NG, G1->getType()));
1218 G2->replaceAllUsesWith(ConstantExpr::getBitCast(NG, G2->getType()));
1220 // Remove the two globals from the module now...
1221 M->getGlobalList().erase(G1);
1222 M->getGlobalList().erase(G2);
1224 // Put the new global into the AppendingVars map so that we can handle
1225 // linking of more than two vars...
1226 Second->second = NG;
1228 AppendingVars.erase(First);
1234 static bool ResolveAliases(Module *Dest) {
1235 for (Module::alias_iterator I = Dest->alias_begin(), E = Dest->alias_end();
1237 if (const GlobalValue *GV = I->resolveAliasedGlobal())
1238 if (!GV->isDeclaration())
1239 I->replaceAllUsesWith(const_cast<GlobalValue*>(GV));
1244 // LinkModules - This function links two modules together, with the resulting
1245 // left module modified to be the composite of the two input modules. If an
1246 // error occurs, true is returned and ErrorMsg (if not null) is set to indicate
1247 // the problem. Upon failure, the Dest module could be in a modified state, and
1248 // shouldn't be relied on to be consistent.
1250 Linker::LinkModules(Module *Dest, Module *Src, std::string *ErrorMsg) {
1251 assert(Dest != 0 && "Invalid Destination module");
1252 assert(Src != 0 && "Invalid Source Module");
1254 if (Dest->getDataLayout().empty()) {
1255 if (!Src->getDataLayout().empty()) {
1256 Dest->setDataLayout(Src->getDataLayout());
1258 std::string DataLayout;
1260 if (Dest->getEndianness() == Module::AnyEndianness) {
1261 if (Src->getEndianness() == Module::BigEndian)
1262 DataLayout.append("E");
1263 else if (Src->getEndianness() == Module::LittleEndian)
1264 DataLayout.append("e");
1267 if (Dest->getPointerSize() == Module::AnyPointerSize) {
1268 if (Src->getPointerSize() == Module::Pointer64)
1269 DataLayout.append(DataLayout.length() == 0 ? "p:64:64" : "-p:64:64");
1270 else if (Src->getPointerSize() == Module::Pointer32)
1271 DataLayout.append(DataLayout.length() == 0 ? "p:32:32" : "-p:32:32");
1273 Dest->setDataLayout(DataLayout);
1277 // Copy the target triple from the source to dest if the dest's is empty.
1278 if (Dest->getTargetTriple().empty() && !Src->getTargetTriple().empty())
1279 Dest->setTargetTriple(Src->getTargetTriple());
1281 if (!Src->getDataLayout().empty() && !Dest->getDataLayout().empty() &&
1282 Src->getDataLayout() != Dest->getDataLayout())
1283 cerr << "WARNING: Linking two modules of different data layouts!\n";
1284 if (!Src->getTargetTriple().empty() &&
1285 Dest->getTargetTriple() != Src->getTargetTriple())
1286 cerr << "WARNING: Linking two modules of different target triples!\n";
1288 // Append the module inline asm string.
1289 if (!Src->getModuleInlineAsm().empty()) {
1290 if (Dest->getModuleInlineAsm().empty())
1291 Dest->setModuleInlineAsm(Src->getModuleInlineAsm());
1293 Dest->setModuleInlineAsm(Dest->getModuleInlineAsm()+"\n"+
1294 Src->getModuleInlineAsm());
1297 // Update the destination module's dependent libraries list with the libraries
1298 // from the source module. There's no opportunity for duplicates here as the
1299 // Module ensures that duplicate insertions are discarded.
1300 for (Module::lib_iterator SI = Src->lib_begin(), SE = Src->lib_end();
1302 Dest->addLibrary(*SI);
1304 // LinkTypes - Go through the symbol table of the Src module and see if any
1305 // types are named in the src module that are not named in the Dst module.
1306 // Make sure there are no type name conflicts.
1307 if (LinkTypes(Dest, Src, ErrorMsg))
1310 // ValueMap - Mapping of values from what they used to be in Src, to what they
1312 std::map<const Value*, Value*> ValueMap;
1314 // AppendingVars - Keep track of global variables in the destination module
1315 // with appending linkage. After the module is linked together, they are
1316 // appended and the module is rewritten.
1317 std::multimap<std::string, GlobalVariable *> AppendingVars;
1318 for (Module::global_iterator I = Dest->global_begin(), E = Dest->global_end();
1320 // Add all of the appending globals already in the Dest module to
1322 if (I->hasAppendingLinkage())
1323 AppendingVars.insert(std::make_pair(I->getName(), I));
1326 // Insert all of the globals in src into the Dest module... without linking
1327 // initializers (which could refer to functions not yet mapped over).
1328 if (LinkGlobals(Dest, Src, ValueMap, AppendingVars, ErrorMsg))
1331 // Link the functions together between the two modules, without doing function
1332 // bodies... this just adds external function prototypes to the Dest
1333 // function... We do this so that when we begin processing function bodies,
1334 // all of the global values that may be referenced are available in our
1336 if (LinkFunctionProtos(Dest, Src, ValueMap, ErrorMsg))
1339 // If there were any alias, link them now. We really need to do this now,
1340 // because all of the aliases that may be referenced need to be available in
1342 if (LinkAlias(Dest, Src, ValueMap, ErrorMsg)) return true;
1344 // Update the initializers in the Dest module now that all globals that may
1345 // be referenced are in Dest.
1346 if (LinkGlobalInits(Dest, Src, ValueMap, ErrorMsg)) return true;
1348 // Link in the function bodies that are defined in the source module into the
1349 // DestModule. This consists basically of copying the function over and
1350 // fixing up references to values.
1351 if (LinkFunctionBodies(Dest, Src, ValueMap, ErrorMsg)) return true;
1353 // If there were any appending global variables, link them together now.
1354 if (LinkAppendingVars(Dest, AppendingVars, ErrorMsg)) return true;
1356 // Resolve all uses of aliases with aliasees
1357 if (ResolveAliases(Dest)) return true;
1359 // If the source library's module id is in the dependent library list of the
1360 // destination library, remove it since that module is now linked in.
1362 modId.set(Src->getModuleIdentifier());
1363 if (!modId.isEmpty())
1364 Dest->removeLibrary(modId.getBasename());