1 //===- lib/Linker/LinkModules.cpp - Module Linker Implementation ----------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements the LLVM module linker.
12 // Specifically, this:
13 // * Merges global variables between the two modules
14 // * Uninit + Uninit = Init, Init + Uninit = Init, Init + Init = Error if !=
15 // * Merges functions between two modules
17 //===----------------------------------------------------------------------===//
19 #include "llvm/Linker.h"
20 #include "llvm/Constants.h"
21 #include "llvm/DerivedTypes.h"
22 #include "llvm/LLVMContext.h"
23 #include "llvm/Module.h"
24 #include "llvm/TypeSymbolTable.h"
25 #include "llvm/ValueSymbolTable.h"
26 #include "llvm/Instructions.h"
27 #include "llvm/Assembly/Writer.h"
28 #include "llvm/Support/ErrorHandling.h"
29 #include "llvm/Support/raw_ostream.h"
30 #include "llvm/System/Path.h"
31 #include "llvm/ADT/DenseMap.h"
34 // Error - Simple wrapper function to conditionally assign to E and return true.
35 // This just makes error return conditions a little bit simpler...
36 static inline bool Error(std::string *E, const Twine &Message) {
37 if (E) *E = Message.str();
41 // Function: ResolveTypes()
44 // Attempt to link the two specified types together.
47 // DestTy - The type to which we wish to resolve.
48 // SrcTy - The original type which we want to resolve.
51 // DestST - The symbol table in which the new type should be placed.
54 // true - There is an error and the types cannot yet be linked.
57 static bool ResolveTypes(const Type *DestTy, const Type *SrcTy) {
58 if (DestTy == SrcTy) return false; // If already equal, noop
59 assert(DestTy && SrcTy && "Can't handle null types");
61 if (const OpaqueType *OT = dyn_cast<OpaqueType>(DestTy)) {
62 // Type _is_ in module, just opaque...
63 const_cast<OpaqueType*>(OT)->refineAbstractTypeTo(SrcTy);
64 } else if (const OpaqueType *OT = dyn_cast<OpaqueType>(SrcTy)) {
65 const_cast<OpaqueType*>(OT)->refineAbstractTypeTo(DestTy);
67 return true; // Cannot link types... not-equal and neither is opaque.
72 /// LinkerTypeMap - This implements a map of types that is stable
73 /// even if types are resolved/refined to other types. This is not a general
74 /// purpose map, it is specific to the linker's use.
76 class LinkerTypeMap : public AbstractTypeUser {
77 typedef DenseMap<const Type*, PATypeHolder> TheMapTy;
80 LinkerTypeMap(const LinkerTypeMap&); // DO NOT IMPLEMENT
81 void operator=(const LinkerTypeMap&); // DO NOT IMPLEMENT
85 for (DenseMap<const Type*, PATypeHolder>::iterator I = TheMap.begin(),
86 E = TheMap.end(); I != E; ++I)
87 I->first->removeAbstractTypeUser(this);
90 /// lookup - Return the value for the specified type or null if it doesn't
92 const Type *lookup(const Type *Ty) const {
93 TheMapTy::const_iterator I = TheMap.find(Ty);
94 if (I != TheMap.end()) return I->second;
98 /// erase - Remove the specified type, returning true if it was in the set.
99 bool erase(const Type *Ty) {
100 if (!TheMap.erase(Ty))
102 if (Ty->isAbstract())
103 Ty->removeAbstractTypeUser(this);
107 /// insert - This returns true if the pointer was new to the set, false if it
108 /// was already in the set.
109 bool insert(const Type *Src, const Type *Dst) {
110 if (!TheMap.insert(std::make_pair(Src, PATypeHolder(Dst))).second)
111 return false; // Already in map.
112 if (Src->isAbstract())
113 Src->addAbstractTypeUser(this);
118 /// refineAbstractType - The callback method invoked when an abstract type is
119 /// resolved to another type. An object must override this method to update
120 /// its internal state to reference NewType instead of OldType.
122 virtual void refineAbstractType(const DerivedType *OldTy,
124 TheMapTy::iterator I = TheMap.find(OldTy);
125 const Type *DstTy = I->second;
128 if (OldTy->isAbstract())
129 OldTy->removeAbstractTypeUser(this);
131 // Don't reinsert into the map if the key is concrete now.
132 if (NewTy->isAbstract())
133 insert(NewTy, DstTy);
136 /// The other case which AbstractTypeUsers must be aware of is when a type
137 /// makes the transition from being abstract (where it has clients on it's
138 /// AbstractTypeUsers list) to concrete (where it does not). This method
139 /// notifies ATU's when this occurs for a type.
140 virtual void typeBecameConcrete(const DerivedType *AbsTy) {
142 AbsTy->removeAbstractTypeUser(this);
146 virtual void dump() const {
147 errs() << "AbstractTypeSet!\n";
153 // RecursiveResolveTypes - This is just like ResolveTypes, except that it
154 // recurses down into derived types, merging the used types if the parent types
156 static bool RecursiveResolveTypesI(const Type *DstTy, const Type *SrcTy,
157 LinkerTypeMap &Pointers) {
158 if (DstTy == SrcTy) return false; // If already equal, noop
160 // If we found our opaque type, resolve it now!
161 if (isa<OpaqueType>(DstTy) || isa<OpaqueType>(SrcTy))
162 return ResolveTypes(DstTy, SrcTy);
164 // Two types cannot be resolved together if they are of different primitive
165 // type. For example, we cannot resolve an int to a float.
166 if (DstTy->getTypeID() != SrcTy->getTypeID()) return true;
168 // If neither type is abstract, then they really are just different types.
169 if (!DstTy->isAbstract() && !SrcTy->isAbstract())
172 // Otherwise, resolve the used type used by this derived type...
173 switch (DstTy->getTypeID()) {
176 case Type::FunctionTyID: {
177 const FunctionType *DstFT = cast<FunctionType>(DstTy);
178 const FunctionType *SrcFT = cast<FunctionType>(SrcTy);
179 if (DstFT->isVarArg() != SrcFT->isVarArg() ||
180 DstFT->getNumContainedTypes() != SrcFT->getNumContainedTypes())
183 // Use TypeHolder's so recursive resolution won't break us.
184 PATypeHolder ST(SrcFT), DT(DstFT);
185 for (unsigned i = 0, e = DstFT->getNumContainedTypes(); i != e; ++i) {
186 const Type *SE = ST->getContainedType(i), *DE = DT->getContainedType(i);
187 if (SE != DE && RecursiveResolveTypesI(DE, SE, Pointers))
192 case Type::StructTyID: {
193 const StructType *DstST = cast<StructType>(DstTy);
194 const StructType *SrcST = cast<StructType>(SrcTy);
195 if (DstST->getNumContainedTypes() != SrcST->getNumContainedTypes())
198 PATypeHolder ST(SrcST), DT(DstST);
199 for (unsigned i = 0, e = DstST->getNumContainedTypes(); i != e; ++i) {
200 const Type *SE = ST->getContainedType(i), *DE = DT->getContainedType(i);
201 if (SE != DE && RecursiveResolveTypesI(DE, SE, Pointers))
206 case Type::ArrayTyID: {
207 const ArrayType *DAT = cast<ArrayType>(DstTy);
208 const ArrayType *SAT = cast<ArrayType>(SrcTy);
209 if (DAT->getNumElements() != SAT->getNumElements()) return true;
210 return RecursiveResolveTypesI(DAT->getElementType(), SAT->getElementType(),
213 case Type::VectorTyID: {
214 const VectorType *DVT = cast<VectorType>(DstTy);
215 const VectorType *SVT = cast<VectorType>(SrcTy);
216 if (DVT->getNumElements() != SVT->getNumElements()) return true;
217 return RecursiveResolveTypesI(DVT->getElementType(), SVT->getElementType(),
220 case Type::PointerTyID: {
221 const PointerType *DstPT = cast<PointerType>(DstTy);
222 const PointerType *SrcPT = cast<PointerType>(SrcTy);
224 if (DstPT->getAddressSpace() != SrcPT->getAddressSpace())
227 // If this is a pointer type, check to see if we have already seen it. If
228 // so, we are in a recursive branch. Cut off the search now. We cannot use
229 // an associative container for this search, because the type pointers (keys
230 // in the container) change whenever types get resolved.
231 if (SrcPT->isAbstract())
232 if (const Type *ExistingDestTy = Pointers.lookup(SrcPT))
233 return ExistingDestTy != DstPT;
235 if (DstPT->isAbstract())
236 if (const Type *ExistingSrcTy = Pointers.lookup(DstPT))
237 return ExistingSrcTy != SrcPT;
238 // Otherwise, add the current pointers to the vector to stop recursion on
240 if (DstPT->isAbstract())
241 Pointers.insert(DstPT, SrcPT);
242 if (SrcPT->isAbstract())
243 Pointers.insert(SrcPT, DstPT);
245 return RecursiveResolveTypesI(DstPT->getElementType(),
246 SrcPT->getElementType(), Pointers);
251 static bool RecursiveResolveTypes(const Type *DestTy, const Type *SrcTy) {
252 LinkerTypeMap PointerTypes;
253 return RecursiveResolveTypesI(DestTy, SrcTy, PointerTypes);
257 // LinkTypes - Go through the symbol table of the Src module and see if any
258 // types are named in the src module that are not named in the Dst module.
259 // Make sure there are no type name conflicts.
260 static bool LinkTypes(Module *Dest, const Module *Src, std::string *Err) {
261 TypeSymbolTable *DestST = &Dest->getTypeSymbolTable();
262 const TypeSymbolTable *SrcST = &Src->getTypeSymbolTable();
264 // Look for a type plane for Type's...
265 TypeSymbolTable::const_iterator TI = SrcST->begin();
266 TypeSymbolTable::const_iterator TE = SrcST->end();
267 if (TI == TE) return false; // No named types, do nothing.
269 // Some types cannot be resolved immediately because they depend on other
270 // types being resolved to each other first. This contains a list of types we
271 // are waiting to recheck.
272 std::vector<std::string> DelayedTypesToResolve;
274 for ( ; TI != TE; ++TI ) {
275 const std::string &Name = TI->first;
276 const Type *RHS = TI->second;
278 // Check to see if this type name is already in the dest module.
279 Type *Entry = DestST->lookup(Name);
281 // If the name is just in the source module, bring it over to the dest.
284 DestST->insert(Name, const_cast<Type*>(RHS));
285 } else if (ResolveTypes(Entry, RHS)) {
286 // They look different, save the types 'till later to resolve.
287 DelayedTypesToResolve.push_back(Name);
291 // Iteratively resolve types while we can...
292 while (!DelayedTypesToResolve.empty()) {
293 // Loop over all of the types, attempting to resolve them if possible...
294 unsigned OldSize = DelayedTypesToResolve.size();
296 // Try direct resolution by name...
297 for (unsigned i = 0; i != DelayedTypesToResolve.size(); ++i) {
298 const std::string &Name = DelayedTypesToResolve[i];
299 Type *T1 = SrcST->lookup(Name);
300 Type *T2 = DestST->lookup(Name);
301 if (!ResolveTypes(T2, T1)) {
302 // We are making progress!
303 DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i);
308 // Did we not eliminate any types?
309 if (DelayedTypesToResolve.size() == OldSize) {
310 // Attempt to resolve subelements of types. This allows us to merge these
311 // two types: { int* } and { opaque* }
312 for (unsigned i = 0, e = DelayedTypesToResolve.size(); i != e; ++i) {
313 const std::string &Name = DelayedTypesToResolve[i];
314 if (!RecursiveResolveTypes(SrcST->lookup(Name), DestST->lookup(Name))) {
315 // We are making progress!
316 DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i);
318 // Go back to the main loop, perhaps we can resolve directly by name
324 // If we STILL cannot resolve the types, then there is something wrong.
325 if (DelayedTypesToResolve.size() == OldSize) {
326 // Remove the symbol name from the destination.
327 DelayedTypesToResolve.pop_back();
337 static void PrintMap(const std::map<const Value*, Value*> &M) {
338 for (std::map<const Value*, Value*>::const_iterator I = M.begin(), E =M.end();
340 errs() << " Fr: " << (void*)I->first << " ";
342 errs() << " To: " << (void*)I->second << " ";
350 // RemapOperand - Use ValueMap to convert constants from one module to another.
351 static Value *RemapOperand(const Value *In,
352 std::map<const Value*, Value*> &ValueMap) {
353 std::map<const Value*,Value*>::const_iterator I = ValueMap.find(In);
354 if (I != ValueMap.end())
357 // Check to see if it's a constant that we are interested in transforming.
359 if (const Constant *CPV = dyn_cast<Constant>(In)) {
360 if ((!isa<DerivedType>(CPV->getType()) && !isa<ConstantExpr>(CPV)) ||
361 isa<ConstantInt>(CPV) || isa<ConstantAggregateZero>(CPV))
362 return const_cast<Constant*>(CPV); // Simple constants stay identical.
364 if (const ConstantArray *CPA = dyn_cast<ConstantArray>(CPV)) {
365 std::vector<Constant*> Operands(CPA->getNumOperands());
366 for (unsigned i = 0, e = CPA->getNumOperands(); i != e; ++i)
367 Operands[i] =cast<Constant>(RemapOperand(CPA->getOperand(i), ValueMap));
368 Result = ConstantArray::get(cast<ArrayType>(CPA->getType()), Operands);
369 } else if (const ConstantStruct *CPS = dyn_cast<ConstantStruct>(CPV)) {
370 std::vector<Constant*> Operands(CPS->getNumOperands());
371 for (unsigned i = 0, e = CPS->getNumOperands(); i != e; ++i)
372 Operands[i] =cast<Constant>(RemapOperand(CPS->getOperand(i), ValueMap));
373 Result = ConstantStruct::get(cast<StructType>(CPS->getType()), Operands);
374 } else if (isa<ConstantPointerNull>(CPV) || isa<UndefValue>(CPV)) {
375 Result = const_cast<Constant*>(CPV);
376 } else if (const ConstantVector *CP = dyn_cast<ConstantVector>(CPV)) {
377 std::vector<Constant*> Operands(CP->getNumOperands());
378 for (unsigned i = 0, e = CP->getNumOperands(); i != e; ++i)
379 Operands[i] = cast<Constant>(RemapOperand(CP->getOperand(i), ValueMap));
380 Result = ConstantVector::get(Operands);
381 } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CPV)) {
382 std::vector<Constant*> Ops;
383 for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i)
384 Ops.push_back(cast<Constant>(RemapOperand(CE->getOperand(i),ValueMap)));
385 Result = CE->getWithOperands(Ops);
386 } else if (const BlockAddress *CE = dyn_cast<BlockAddress>(CPV)) {
387 Result = BlockAddress::get(
388 cast<Function>(RemapOperand(CE->getFunction(), ValueMap)),
389 CE->getBasicBlock());
391 assert(!isa<GlobalValue>(CPV) && "Unmapped global?");
392 llvm_unreachable("Unknown type of derived type constant value!");
394 } else if (isa<MetadataBase>(In)) {
395 Result = const_cast<Value*>(In);
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 errs() << "LinkModules ValueMap: \n";
410 errs() << "Couldn't remap value: " << (void*)In << " " << *In << "\n";
411 llvm_unreachable("Couldn't remap value!");
416 /// ForceRenaming - The LLVM SymbolTable class autorenames globals that conflict
417 /// in the symbol table. This is good for all clients except for us. Go
418 /// through the trouble to force this back.
419 static void ForceRenaming(GlobalValue *GV, const std::string &Name) {
420 assert(GV->getName() != Name && "Can't force rename to self");
421 ValueSymbolTable &ST = GV->getParent()->getValueSymbolTable();
423 // If there is a conflict, rename the conflict.
424 if (GlobalValue *ConflictGV = cast_or_null<GlobalValue>(ST.lookup(Name))) {
425 assert(ConflictGV->hasLocalLinkage() &&
426 "Not conflicting with a static global, should link instead!");
427 GV->takeName(ConflictGV);
428 ConflictGV->setName(Name); // This will cause ConflictGV to get renamed
429 assert(ConflictGV->getName() != Name && "ForceRenaming didn't work");
431 GV->setName(Name); // Force the name back
435 /// CopyGVAttributes - copy additional attributes (those not needed to construct
436 /// a GlobalValue) from the SrcGV to the DestGV.
437 static void CopyGVAttributes(GlobalValue *DestGV, const GlobalValue *SrcGV) {
438 // Use the maximum alignment, rather than just copying the alignment of SrcGV.
439 unsigned Alignment = std::max(DestGV->getAlignment(), SrcGV->getAlignment());
440 DestGV->copyAttributesFrom(SrcGV);
441 DestGV->setAlignment(Alignment);
444 /// GetLinkageResult - This analyzes the two global values and determines what
445 /// the result will look like in the destination module. In particular, it
446 /// computes the resultant linkage type, computes whether the global in the
447 /// source should be copied over to the destination (replacing the existing
448 /// one), and computes whether this linkage is an error or not. It also performs
449 /// visibility checks: we cannot link together two symbols with different
451 static bool GetLinkageResult(GlobalValue *Dest, const GlobalValue *Src,
452 GlobalValue::LinkageTypes <, bool &LinkFromSrc,
454 assert((!Dest || !Src->hasLocalLinkage()) &&
455 "If Src has internal linkage, Dest shouldn't be set!");
457 // Linking something to nothing.
459 LT = Src->getLinkage();
460 } else if (Src->isDeclaration()) {
461 // If Src is external or if both Src & Dest are external.. Just link the
462 // external globals, we aren't adding anything.
463 if (Src->hasDLLImportLinkage()) {
464 // If one of GVs has DLLImport linkage, result should be dllimport'ed.
465 if (Dest->isDeclaration()) {
467 LT = Src->getLinkage();
469 } else if (Dest->hasExternalWeakLinkage()) {
470 // If the Dest is weak, use the source linkage.
472 LT = Src->getLinkage();
475 LT = Dest->getLinkage();
477 } else if (Dest->isDeclaration() && !Dest->hasDLLImportLinkage()) {
478 // If Dest is external but Src is not:
480 LT = Src->getLinkage();
481 } else if (Src->hasAppendingLinkage() || Dest->hasAppendingLinkage()) {
482 if (Src->getLinkage() != Dest->getLinkage())
483 return Error(Err, "Linking globals named '" + Src->getName() +
484 "': can only link appending global with another appending global!");
485 LinkFromSrc = true; // Special cased.
486 LT = Src->getLinkage();
487 } else if (Src->isWeakForLinker()) {
488 // At this point we know that Dest has LinkOnce, External*, Weak, Common,
490 if (Dest->hasExternalWeakLinkage() ||
491 Dest->hasAvailableExternallyLinkage() ||
492 (Dest->hasLinkOnceLinkage() &&
493 (Src->hasWeakLinkage() || Src->hasCommonLinkage()))) {
495 LT = Src->getLinkage();
498 LT = Dest->getLinkage();
500 } else if (Dest->isWeakForLinker()) {
501 // At this point we know that Src has External* or DLL* linkage.
502 if (Src->hasExternalWeakLinkage()) {
504 LT = Dest->getLinkage();
507 LT = GlobalValue::ExternalLinkage;
510 assert((Dest->hasExternalLinkage() ||
511 Dest->hasDLLImportLinkage() ||
512 Dest->hasDLLExportLinkage() ||
513 Dest->hasExternalWeakLinkage()) &&
514 (Src->hasExternalLinkage() ||
515 Src->hasDLLImportLinkage() ||
516 Src->hasDLLExportLinkage() ||
517 Src->hasExternalWeakLinkage()) &&
518 "Unexpected linkage type!");
519 return Error(Err, "Linking globals named '" + Src->getName() +
520 "': symbol multiply defined!");
524 if (Dest && Src->getVisibility() != Dest->getVisibility())
525 if (!Src->isDeclaration() && !Dest->isDeclaration())
526 return Error(Err, "Linking globals named '" + Src->getName() +
527 "': symbols have different visibilities!");
531 // Insert all of the named mdnoes in Src into the Dest module.
532 static void LinkNamedMDNodes(Module *Dest, Module *Src) {
533 for (Module::const_named_metadata_iterator I = Src->named_metadata_begin(),
534 E = Src->named_metadata_end(); I != E; ++I) {
535 const NamedMDNode *SrcNMD = I;
536 NamedMDNode *DestNMD = Dest->getNamedMetadata(SrcNMD->getName());
538 NamedMDNode::Create(SrcNMD, Dest);
540 // Add Src elements into Dest node.
541 for (unsigned i = 0, e = SrcNMD->getNumElements(); i != e; ++i)
542 DestNMD->addElement(SrcNMD->getElement(i));
547 // LinkGlobals - Loop through the global variables in the src module and merge
548 // them into the dest module.
549 static bool LinkGlobals(Module *Dest, const Module *Src,
550 std::map<const Value*, Value*> &ValueMap,
551 std::multimap<std::string, GlobalVariable *> &AppendingVars,
553 ValueSymbolTable &DestSymTab = Dest->getValueSymbolTable();
555 // Loop over all of the globals in the src module, mapping them over as we go
556 for (Module::const_global_iterator I = Src->global_begin(),
557 E = Src->global_end(); I != E; ++I) {
558 const GlobalVariable *SGV = I;
559 GlobalValue *DGV = 0;
561 // Check to see if may have to link the global with the global, alias or
563 if (SGV->hasName() && !SGV->hasLocalLinkage())
564 DGV = cast_or_null<GlobalValue>(DestSymTab.lookup(SGV->getName()));
566 // If we found a global with the same name in the dest module, but it has
567 // internal linkage, we are really not doing any linkage here.
568 if (DGV && DGV->hasLocalLinkage())
571 // If types don't agree due to opaque types, try to resolve them.
572 if (DGV && DGV->getType() != SGV->getType())
573 RecursiveResolveTypes(SGV->getType(), DGV->getType());
575 assert((SGV->hasInitializer() || SGV->hasExternalWeakLinkage() ||
576 SGV->hasExternalLinkage() || SGV->hasDLLImportLinkage()) &&
577 "Global must either be external or have an initializer!");
579 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage;
580 bool LinkFromSrc = false;
581 if (GetLinkageResult(DGV, SGV, NewLinkage, LinkFromSrc, Err))
585 // No linking to be performed, simply create an identical version of the
586 // symbol over in the dest module... the initializer will be filled in
587 // later by LinkGlobalInits.
588 GlobalVariable *NewDGV =
589 new GlobalVariable(*Dest, SGV->getType()->getElementType(),
590 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
591 SGV->getName(), 0, false,
592 SGV->getType()->getAddressSpace());
593 // Propagate alignment, visibility and section info.
594 CopyGVAttributes(NewDGV, SGV);
596 // If the LLVM runtime renamed the global, but it is an externally visible
597 // symbol, DGV must be an existing global with internal linkage. Rename
599 if (!NewDGV->hasLocalLinkage() && NewDGV->getName() != SGV->getName())
600 ForceRenaming(NewDGV, SGV->getName());
602 // Make sure to remember this mapping.
603 ValueMap[SGV] = NewDGV;
605 // Keep track that this is an appending variable.
606 if (SGV->hasAppendingLinkage())
607 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV));
611 // If the visibilities of the symbols disagree and the destination is a
612 // prototype, take the visibility of its input.
613 if (DGV->isDeclaration())
614 DGV->setVisibility(SGV->getVisibility());
616 if (DGV->hasAppendingLinkage()) {
617 // No linking is performed yet. Just insert a new copy of the global, and
618 // keep track of the fact that it is an appending variable in the
619 // AppendingVars map. The name is cleared out so that no linkage is
621 GlobalVariable *NewDGV =
622 new GlobalVariable(*Dest, SGV->getType()->getElementType(),
623 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
625 SGV->getType()->getAddressSpace());
627 // Set alignment allowing CopyGVAttributes merge it with alignment of SGV.
628 NewDGV->setAlignment(DGV->getAlignment());
629 // Propagate alignment, section and visibility info.
630 CopyGVAttributes(NewDGV, SGV);
632 // Make sure to remember this mapping...
633 ValueMap[SGV] = NewDGV;
635 // Keep track that this is an appending variable...
636 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV));
641 if (isa<GlobalAlias>(DGV))
642 return Error(Err, "Global-Alias Collision on '" + SGV->getName() +
643 "': symbol multiple defined");
645 // If the types don't match, and if we are to link from the source, nuke
646 // DGV and create a new one of the appropriate type. Note that the thing
647 // we are replacing may be a function (if a prototype, weak, etc) or a
649 GlobalVariable *NewDGV =
650 new GlobalVariable(*Dest, SGV->getType()->getElementType(),
651 SGV->isConstant(), NewLinkage, /*init*/0,
652 DGV->getName(), 0, false,
653 SGV->getType()->getAddressSpace());
655 // Propagate alignment, section, and visibility info.
656 CopyGVAttributes(NewDGV, SGV);
657 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDGV,
660 // DGV will conflict with NewDGV because they both had the same
661 // name. We must erase this now so ForceRenaming doesn't assert
662 // because DGV might not have internal linkage.
663 if (GlobalVariable *Var = dyn_cast<GlobalVariable>(DGV))
664 Var->eraseFromParent();
666 cast<Function>(DGV)->eraseFromParent();
669 // If the symbol table renamed the global, but it is an externally visible
670 // symbol, DGV must be an existing global with internal linkage. Rename.
671 if (NewDGV->getName() != SGV->getName() && !NewDGV->hasLocalLinkage())
672 ForceRenaming(NewDGV, SGV->getName());
674 // Inherit const as appropriate.
675 NewDGV->setConstant(SGV->isConstant());
677 // Make sure to remember this mapping.
678 ValueMap[SGV] = NewDGV;
682 // Not "link from source", keep the one in the DestModule and remap the
685 // Special case for const propagation.
686 if (GlobalVariable *DGVar = dyn_cast<GlobalVariable>(DGV))
687 if (DGVar->isDeclaration() && SGV->isConstant() && !DGVar->isConstant())
688 DGVar->setConstant(true);
690 // SGV is global, but DGV is alias.
691 if (isa<GlobalAlias>(DGV)) {
692 // The only valid mappings are:
693 // - SGV is external declaration, which is effectively a no-op.
694 // - SGV is weak, when we just need to throw SGV out.
695 if (!SGV->isDeclaration() && !SGV->isWeakForLinker())
696 return Error(Err, "Global-Alias Collision on '" + SGV->getName() +
697 "': symbol multiple defined");
700 // Set calculated linkage
701 DGV->setLinkage(NewLinkage);
703 // Make sure to remember this mapping...
704 ValueMap[SGV] = ConstantExpr::getBitCast(DGV, SGV->getType());
709 static GlobalValue::LinkageTypes
710 CalculateAliasLinkage(const GlobalValue *SGV, const GlobalValue *DGV) {
711 GlobalValue::LinkageTypes SL = SGV->getLinkage();
712 GlobalValue::LinkageTypes DL = DGV->getLinkage();
713 if (SL == GlobalValue::ExternalLinkage || DL == GlobalValue::ExternalLinkage)
714 return GlobalValue::ExternalLinkage;
715 else if (SL == GlobalValue::WeakAnyLinkage ||
716 DL == GlobalValue::WeakAnyLinkage)
717 return GlobalValue::WeakAnyLinkage;
718 else if (SL == GlobalValue::WeakODRLinkage ||
719 DL == GlobalValue::WeakODRLinkage)
720 return GlobalValue::WeakODRLinkage;
721 else if (SL == GlobalValue::InternalLinkage &&
722 DL == GlobalValue::InternalLinkage)
723 return GlobalValue::InternalLinkage;
724 else if (SL == GlobalValue::LinkerPrivateLinkage &&
725 DL == GlobalValue::LinkerPrivateLinkage)
726 return GlobalValue::LinkerPrivateLinkage;
728 assert (SL == GlobalValue::PrivateLinkage &&
729 DL == GlobalValue::PrivateLinkage && "Unexpected linkage type");
730 return GlobalValue::PrivateLinkage;
734 // LinkAlias - Loop through the alias in the src module and link them into the
735 // dest module. We're assuming, that all functions/global variables were already
737 static bool LinkAlias(Module *Dest, const Module *Src,
738 std::map<const Value*, Value*> &ValueMap,
740 // Loop over all alias in the src module
741 for (Module::const_alias_iterator I = Src->alias_begin(),
742 E = Src->alias_end(); I != E; ++I) {
743 const GlobalAlias *SGA = I;
744 const GlobalValue *SAliasee = SGA->getAliasedGlobal();
745 GlobalAlias *NewGA = NULL;
747 // Globals were already linked, thus we can just query ValueMap for variant
748 // of SAliasee in Dest.
749 std::map<const Value*,Value*>::const_iterator VMI = ValueMap.find(SAliasee);
750 assert(VMI != ValueMap.end() && "Aliasee not linked");
751 GlobalValue* DAliasee = cast<GlobalValue>(VMI->second);
752 GlobalValue* DGV = NULL;
754 // Try to find something 'similar' to SGA in destination module.
755 if (!DGV && !SGA->hasLocalLinkage()) {
756 DGV = Dest->getNamedAlias(SGA->getName());
758 // If types don't agree due to opaque types, try to resolve them.
759 if (DGV && DGV->getType() != SGA->getType())
760 RecursiveResolveTypes(SGA->getType(), DGV->getType());
763 if (!DGV && !SGA->hasLocalLinkage()) {
764 DGV = Dest->getGlobalVariable(SGA->getName());
766 // If types don't agree due to opaque types, try to resolve them.
767 if (DGV && DGV->getType() != SGA->getType())
768 RecursiveResolveTypes(SGA->getType(), DGV->getType());
771 if (!DGV && !SGA->hasLocalLinkage()) {
772 DGV = Dest->getFunction(SGA->getName());
774 // If types don't agree due to opaque types, try to resolve them.
775 if (DGV && DGV->getType() != SGA->getType())
776 RecursiveResolveTypes(SGA->getType(), DGV->getType());
779 // No linking to be performed on internal stuff.
780 if (DGV && DGV->hasLocalLinkage())
783 if (GlobalAlias *DGA = dyn_cast_or_null<GlobalAlias>(DGV)) {
784 // Types are known to be the same, check whether aliasees equal. As
785 // globals are already linked we just need query ValueMap to find the
787 if (DAliasee == DGA->getAliasedGlobal()) {
788 // This is just two copies of the same alias. Propagate linkage, if
790 DGA->setLinkage(CalculateAliasLinkage(SGA, DGA));
793 // Proceed to 'common' steps
795 return Error(Err, "Alias Collision on '" + SGA->getName()+
796 "': aliases have different aliasees");
797 } else if (GlobalVariable *DGVar = dyn_cast_or_null<GlobalVariable>(DGV)) {
798 // The only allowed way is to link alias with external declaration or weak
800 if (DGVar->isDeclaration() || DGVar->isWeakForLinker()) {
801 // But only if aliasee is global too...
802 if (!isa<GlobalVariable>(DAliasee))
803 return Error(Err, "Global-Alias Collision on '" + SGA->getName() +
804 "': aliasee is not global variable");
806 NewGA = new GlobalAlias(SGA->getType(), SGA->getLinkage(),
807 SGA->getName(), DAliasee, Dest);
808 CopyGVAttributes(NewGA, SGA);
810 // Any uses of DGV need to change to NewGA, with cast, if needed.
811 if (SGA->getType() != DGVar->getType())
812 DGVar->replaceAllUsesWith(ConstantExpr::getBitCast(NewGA,
815 DGVar->replaceAllUsesWith(NewGA);
817 // DGVar will conflict with NewGA because they both had the same
818 // name. We must erase this now so ForceRenaming doesn't assert
819 // because DGV might not have internal linkage.
820 DGVar->eraseFromParent();
822 // Proceed to 'common' steps
824 return Error(Err, "Global-Alias Collision on '" + SGA->getName() +
825 "': symbol multiple defined");
826 } else if (Function *DF = dyn_cast_or_null<Function>(DGV)) {
827 // The only allowed way is to link alias with external declaration or weak
829 if (DF->isDeclaration() || DF->isWeakForLinker()) {
830 // But only if aliasee is function too...
831 if (!isa<Function>(DAliasee))
832 return Error(Err, "Function-Alias Collision on '" + SGA->getName() +
833 "': aliasee is not function");
835 NewGA = new GlobalAlias(SGA->getType(), SGA->getLinkage(),
836 SGA->getName(), DAliasee, Dest);
837 CopyGVAttributes(NewGA, SGA);
839 // Any uses of DF need to change to NewGA, with cast, if needed.
840 if (SGA->getType() != DF->getType())
841 DF->replaceAllUsesWith(ConstantExpr::getBitCast(NewGA,
844 DF->replaceAllUsesWith(NewGA);
846 // DF will conflict with NewGA because they both had the same
847 // name. We must erase this now so ForceRenaming doesn't assert
848 // because DF might not have internal linkage.
849 DF->eraseFromParent();
851 // Proceed to 'common' steps
853 return Error(Err, "Function-Alias Collision on '" + SGA->getName() +
854 "': symbol multiple defined");
856 // No linking to be performed, simply create an identical version of the
857 // alias over in the dest module...
859 NewGA = new GlobalAlias(SGA->getType(), SGA->getLinkage(),
860 SGA->getName(), DAliasee, Dest);
861 CopyGVAttributes(NewGA, SGA);
863 // Proceed to 'common' steps
866 assert(NewGA && "No alias was created in destination module!");
868 // If the symbol table renamed the alias, but it is an externally visible
869 // symbol, DGA must be an global value with internal linkage. Rename it.
870 if (NewGA->getName() != SGA->getName() &&
871 !NewGA->hasLocalLinkage())
872 ForceRenaming(NewGA, SGA->getName());
874 // Remember this mapping so uses in the source module get remapped
875 // later by RemapOperand.
876 ValueMap[SGA] = NewGA;
883 // LinkGlobalInits - Update the initializers in the Dest module now that all
884 // globals that may be referenced are in Dest.
885 static bool LinkGlobalInits(Module *Dest, const Module *Src,
886 std::map<const Value*, Value*> &ValueMap,
888 // Loop over all of the globals in the src module, mapping them over as we go
889 for (Module::const_global_iterator I = Src->global_begin(),
890 E = Src->global_end(); I != E; ++I) {
891 const GlobalVariable *SGV = I;
893 if (SGV->hasInitializer()) { // Only process initialized GV's
894 // Figure out what the initializer looks like in the dest module...
896 cast<Constant>(RemapOperand(SGV->getInitializer(), ValueMap));
897 // Grab destination global variable or alias.
898 GlobalValue *DGV = cast<GlobalValue>(ValueMap[SGV]->stripPointerCasts());
900 // If dest if global variable, check that initializers match.
901 if (GlobalVariable *DGVar = dyn_cast<GlobalVariable>(DGV)) {
902 if (DGVar->hasInitializer()) {
903 if (SGV->hasExternalLinkage()) {
904 if (DGVar->getInitializer() != SInit)
905 return Error(Err, "Global Variable Collision on '" +
907 "': global variables have different initializers");
908 } else if (DGVar->isWeakForLinker()) {
909 // Nothing is required, mapped values will take the new global
911 } else if (SGV->isWeakForLinker()) {
912 // Nothing is required, mapped values will take the new global
914 } else if (DGVar->hasAppendingLinkage()) {
915 llvm_unreachable("Appending linkage unimplemented!");
917 llvm_unreachable("Unknown linkage!");
920 // Copy the initializer over now...
921 DGVar->setInitializer(SInit);
924 // Destination is alias, the only valid situation is when source is
925 // weak. Also, note, that we already checked linkage in LinkGlobals(),
926 // thus we assert here.
927 // FIXME: Should we weaken this assumption, 'dereference' alias and
928 // check for initializer of aliasee?
929 assert(SGV->isWeakForLinker());
936 // LinkFunctionProtos - Link the functions together between the two modules,
937 // without doing function bodies... this just adds external function prototypes
938 // to the Dest function...
940 static bool LinkFunctionProtos(Module *Dest, const Module *Src,
941 std::map<const Value*, Value*> &ValueMap,
943 ValueSymbolTable &DestSymTab = Dest->getValueSymbolTable();
945 // Loop over all of the functions in the src module, mapping them over
946 for (Module::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) {
947 const Function *SF = I; // SrcFunction
948 GlobalValue *DGV = 0;
950 // Check to see if may have to link the function with the global, alias or
952 if (SF->hasName() && !SF->hasLocalLinkage())
953 DGV = cast_or_null<GlobalValue>(DestSymTab.lookup(SF->getName()));
955 // If we found a global with the same name in the dest module, but it has
956 // internal linkage, we are really not doing any linkage here.
957 if (DGV && DGV->hasLocalLinkage())
960 // If types don't agree due to opaque types, try to resolve them.
961 if (DGV && DGV->getType() != SF->getType())
962 RecursiveResolveTypes(SF->getType(), DGV->getType());
964 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage;
965 bool LinkFromSrc = false;
966 if (GetLinkageResult(DGV, SF, NewLinkage, LinkFromSrc, Err))
969 // If there is no linkage to be performed, just bring over SF without
972 // Function does not already exist, simply insert an function signature
973 // identical to SF into the dest module.
974 Function *NewDF = Function::Create(SF->getFunctionType(),
976 SF->getName(), Dest);
977 CopyGVAttributes(NewDF, SF);
979 // If the LLVM runtime renamed the function, but it is an externally
980 // visible symbol, DF must be an existing function with internal linkage.
982 if (!NewDF->hasLocalLinkage() && NewDF->getName() != SF->getName())
983 ForceRenaming(NewDF, SF->getName());
985 // ... and remember this mapping...
986 ValueMap[SF] = NewDF;
990 // If the visibilities of the symbols disagree and the destination is a
991 // prototype, take the visibility of its input.
992 if (DGV->isDeclaration())
993 DGV->setVisibility(SF->getVisibility());
996 if (isa<GlobalAlias>(DGV))
997 return Error(Err, "Function-Alias Collision on '" + SF->getName() +
998 "': symbol multiple defined");
1000 // We have a definition of the same name but different type in the
1001 // source module. Copy the prototype to the destination and replace
1002 // uses of the destination's prototype with the new prototype.
1003 Function *NewDF = Function::Create(SF->getFunctionType(), NewLinkage,
1004 SF->getName(), Dest);
1005 CopyGVAttributes(NewDF, SF);
1007 // Any uses of DF need to change to NewDF, with cast
1008 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDF,
1011 // DF will conflict with NewDF because they both had the same. We must
1012 // erase this now so ForceRenaming doesn't assert because DF might
1013 // not have internal linkage.
1014 if (GlobalVariable *Var = dyn_cast<GlobalVariable>(DGV))
1015 Var->eraseFromParent();
1017 cast<Function>(DGV)->eraseFromParent();
1019 // If the symbol table renamed the function, but it is an externally
1020 // visible symbol, DF must be an existing function with internal
1021 // linkage. Rename it.
1022 if (NewDF->getName() != SF->getName() && !NewDF->hasLocalLinkage())
1023 ForceRenaming(NewDF, SF->getName());
1025 // Remember this mapping so uses in the source module get remapped
1026 // later by RemapOperand.
1027 ValueMap[SF] = NewDF;
1031 // Not "link from source", keep the one in the DestModule and remap the
1034 if (isa<GlobalAlias>(DGV)) {
1035 // The only valid mappings are:
1036 // - SF is external declaration, which is effectively a no-op.
1037 // - SF is weak, when we just need to throw SF out.
1038 if (!SF->isDeclaration() && !SF->isWeakForLinker())
1039 return Error(Err, "Function-Alias Collision on '" + SF->getName() +
1040 "': symbol multiple defined");
1043 // Set calculated linkage
1044 DGV->setLinkage(NewLinkage);
1046 // Make sure to remember this mapping.
1047 ValueMap[SF] = ConstantExpr::getBitCast(DGV, SF->getType());
1052 // LinkFunctionBody - Copy the source function over into the dest function and
1053 // fix up references to values. At this point we know that Dest is an external
1054 // function, and that Src is not.
1055 static bool LinkFunctionBody(Function *Dest, Function *Src,
1056 std::map<const Value*, Value*> &ValueMap,
1058 assert(Src && Dest && Dest->isDeclaration() && !Src->isDeclaration());
1060 // Go through and convert function arguments over, remembering the mapping.
1061 Function::arg_iterator DI = Dest->arg_begin();
1062 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end();
1063 I != E; ++I, ++DI) {
1064 DI->setName(I->getName()); // Copy the name information over...
1066 // Add a mapping to our local map
1070 // Splice the body of the source function into the dest function.
1071 Dest->getBasicBlockList().splice(Dest->end(), Src->getBasicBlockList());
1073 // At this point, all of the instructions and values of the function are now
1074 // copied over. The only problem is that they are still referencing values in
1075 // the Source function as operands. Loop through all of the operands of the
1076 // functions and patch them up to point to the local versions...
1078 for (Function::iterator BB = Dest->begin(), BE = Dest->end(); BB != BE; ++BB)
1079 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
1080 for (Instruction::op_iterator OI = I->op_begin(), OE = I->op_end();
1082 if (!isa<Instruction>(*OI) && !isa<BasicBlock>(*OI))
1083 *OI = RemapOperand(*OI, ValueMap);
1085 // There is no need to map the arguments anymore.
1086 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end();
1094 // LinkFunctionBodies - Link in the function bodies that are defined in the
1095 // source module into the DestModule. This consists basically of copying the
1096 // function over and fixing up references to values.
1097 static bool LinkFunctionBodies(Module *Dest, Module *Src,
1098 std::map<const Value*, Value*> &ValueMap,
1101 // Loop over all of the functions in the src module, mapping them over as we
1103 for (Module::iterator SF = Src->begin(), E = Src->end(); SF != E; ++SF) {
1104 if (!SF->isDeclaration()) { // No body if function is external
1105 Function *DF = dyn_cast<Function>(ValueMap[SF]); // Destination function
1107 // DF not external SF external?
1108 if (DF && DF->isDeclaration())
1109 // Only provide the function body if there isn't one already.
1110 if (LinkFunctionBody(DF, SF, ValueMap, Err))
1117 // LinkAppendingVars - If there were any appending global variables, link them
1118 // together now. Return true on error.
1119 static bool LinkAppendingVars(Module *M,
1120 std::multimap<std::string, GlobalVariable *> &AppendingVars,
1121 std::string *ErrorMsg) {
1122 if (AppendingVars.empty()) return false; // Nothing to do.
1124 // Loop over the multimap of appending vars, processing any variables with the
1125 // same name, forming a new appending global variable with both of the
1126 // initializers merged together, then rewrite references to the old variables
1128 std::vector<Constant*> Inits;
1129 while (AppendingVars.size() > 1) {
1130 // Get the first two elements in the map...
1131 std::multimap<std::string,
1132 GlobalVariable*>::iterator Second = AppendingVars.begin(), First=Second++;
1134 // If the first two elements are for different names, there is no pair...
1135 // Otherwise there is a pair, so link them together...
1136 if (First->first == Second->first) {
1137 GlobalVariable *G1 = First->second, *G2 = Second->second;
1138 const ArrayType *T1 = cast<ArrayType>(G1->getType()->getElementType());
1139 const ArrayType *T2 = cast<ArrayType>(G2->getType()->getElementType());
1141 // Check to see that they two arrays agree on type...
1142 if (T1->getElementType() != T2->getElementType())
1143 return Error(ErrorMsg,
1144 "Appending variables with different element types need to be linked!");
1145 if (G1->isConstant() != G2->isConstant())
1146 return Error(ErrorMsg,
1147 "Appending variables linked with different const'ness!");
1149 if (G1->getAlignment() != G2->getAlignment())
1150 return Error(ErrorMsg,
1151 "Appending variables with different alignment need to be linked!");
1153 if (G1->getVisibility() != G2->getVisibility())
1154 return Error(ErrorMsg,
1155 "Appending variables with different visibility need to be linked!");
1157 if (G1->getSection() != G2->getSection())
1158 return Error(ErrorMsg,
1159 "Appending variables with different section name need to be linked!");
1161 unsigned NewSize = T1->getNumElements() + T2->getNumElements();
1162 ArrayType *NewType = ArrayType::get(T1->getElementType(),
1165 G1->setName(""); // Clear G1's name in case of a conflict!
1167 // Create the new global variable...
1168 GlobalVariable *NG =
1169 new GlobalVariable(*M, NewType, G1->isConstant(), G1->getLinkage(),
1170 /*init*/0, First->first, 0, G1->isThreadLocal(),
1171 G1->getType()->getAddressSpace());
1173 // Propagate alignment, visibility and section info.
1174 CopyGVAttributes(NG, G1);
1176 // Merge the initializer...
1177 Inits.reserve(NewSize);
1178 if (ConstantArray *I = dyn_cast<ConstantArray>(G1->getInitializer())) {
1179 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i)
1180 Inits.push_back(I->getOperand(i));
1182 assert(isa<ConstantAggregateZero>(G1->getInitializer()));
1183 Constant *CV = Constant::getNullValue(T1->getElementType());
1184 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i)
1185 Inits.push_back(CV);
1187 if (ConstantArray *I = dyn_cast<ConstantArray>(G2->getInitializer())) {
1188 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i)
1189 Inits.push_back(I->getOperand(i));
1191 assert(isa<ConstantAggregateZero>(G2->getInitializer()));
1192 Constant *CV = Constant::getNullValue(T2->getElementType());
1193 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i)
1194 Inits.push_back(CV);
1196 NG->setInitializer(ConstantArray::get(NewType, Inits));
1199 // Replace any uses of the two global variables with uses of the new
1202 // FIXME: This should rewrite simple/straight-forward uses such as
1203 // getelementptr instructions to not use the Cast!
1204 G1->replaceAllUsesWith(ConstantExpr::getBitCast(NG,
1206 G2->replaceAllUsesWith(ConstantExpr::getBitCast(NG,
1209 // Remove the two globals from the module now...
1210 M->getGlobalList().erase(G1);
1211 M->getGlobalList().erase(G2);
1213 // Put the new global into the AppendingVars map so that we can handle
1214 // linking of more than two vars...
1215 Second->second = NG;
1217 AppendingVars.erase(First);
1223 static bool ResolveAliases(Module *Dest) {
1224 for (Module::alias_iterator I = Dest->alias_begin(), E = Dest->alias_end();
1226 if (const GlobalValue *GV = I->resolveAliasedGlobal())
1227 if (GV != I && !GV->isDeclaration())
1228 I->replaceAllUsesWith(const_cast<GlobalValue*>(GV));
1233 // LinkModules - This function links two modules together, with the resulting
1234 // left module modified to be the composite of the two input modules. If an
1235 // error occurs, true is returned and ErrorMsg (if not null) is set to indicate
1236 // the problem. Upon failure, the Dest module could be in a modified state, and
1237 // shouldn't be relied on to be consistent.
1239 Linker::LinkModules(Module *Dest, Module *Src, std::string *ErrorMsg) {
1240 assert(Dest != 0 && "Invalid Destination module");
1241 assert(Src != 0 && "Invalid Source Module");
1243 if (Dest->getDataLayout().empty()) {
1244 if (!Src->getDataLayout().empty()) {
1245 Dest->setDataLayout(Src->getDataLayout());
1247 std::string DataLayout;
1249 if (Dest->getEndianness() == Module::AnyEndianness) {
1250 if (Src->getEndianness() == Module::BigEndian)
1251 DataLayout.append("E");
1252 else if (Src->getEndianness() == Module::LittleEndian)
1253 DataLayout.append("e");
1256 if (Dest->getPointerSize() == Module::AnyPointerSize) {
1257 if (Src->getPointerSize() == Module::Pointer64)
1258 DataLayout.append(DataLayout.length() == 0 ? "p:64:64" : "-p:64:64");
1259 else if (Src->getPointerSize() == Module::Pointer32)
1260 DataLayout.append(DataLayout.length() == 0 ? "p:32:32" : "-p:32:32");
1262 Dest->setDataLayout(DataLayout);
1266 // Copy the target triple from the source to dest if the dest's is empty.
1267 if (Dest->getTargetTriple().empty() && !Src->getTargetTriple().empty())
1268 Dest->setTargetTriple(Src->getTargetTriple());
1270 if (!Src->getDataLayout().empty() && !Dest->getDataLayout().empty() &&
1271 Src->getDataLayout() != Dest->getDataLayout())
1272 errs() << "WARNING: Linking two modules of different data layouts!\n";
1273 if (!Src->getTargetTriple().empty() &&
1274 Dest->getTargetTriple() != Src->getTargetTriple())
1275 errs() << "WARNING: Linking two modules of different target triples!\n";
1277 // Append the module inline asm string.
1278 if (!Src->getModuleInlineAsm().empty()) {
1279 if (Dest->getModuleInlineAsm().empty())
1280 Dest->setModuleInlineAsm(Src->getModuleInlineAsm());
1282 Dest->setModuleInlineAsm(Dest->getModuleInlineAsm()+"\n"+
1283 Src->getModuleInlineAsm());
1286 // Update the destination module's dependent libraries list with the libraries
1287 // from the source module. There's no opportunity for duplicates here as the
1288 // Module ensures that duplicate insertions are discarded.
1289 for (Module::lib_iterator SI = Src->lib_begin(), SE = Src->lib_end();
1291 Dest->addLibrary(*SI);
1293 // LinkTypes - Go through the symbol table of the Src module and see if any
1294 // types are named in the src module that are not named in the Dst module.
1295 // Make sure there are no type name conflicts.
1296 if (LinkTypes(Dest, Src, ErrorMsg))
1299 // ValueMap - Mapping of values from what they used to be in Src, to what they
1301 std::map<const Value*, Value*> ValueMap;
1303 // AppendingVars - Keep track of global variables in the destination module
1304 // with appending linkage. After the module is linked together, they are
1305 // appended and the module is rewritten.
1306 std::multimap<std::string, GlobalVariable *> AppendingVars;
1307 for (Module::global_iterator I = Dest->global_begin(), E = Dest->global_end();
1309 // Add all of the appending globals already in the Dest module to
1311 if (I->hasAppendingLinkage())
1312 AppendingVars.insert(std::make_pair(I->getName(), I));
1315 // Insert all of the named mdnoes in Src into the Dest module.
1316 LinkNamedMDNodes(Dest, Src);
1318 // Insert all of the globals in src into the Dest module... without linking
1319 // initializers (which could refer to functions not yet mapped over).
1320 if (LinkGlobals(Dest, Src, ValueMap, AppendingVars, ErrorMsg))
1323 // Link the functions together between the two modules, without doing function
1324 // bodies... this just adds external function prototypes to the Dest
1325 // function... We do this so that when we begin processing function bodies,
1326 // all of the global values that may be referenced are available in our
1328 if (LinkFunctionProtos(Dest, Src, ValueMap, ErrorMsg))
1331 // If there were any alias, link them now. We really need to do this now,
1332 // because all of the aliases that may be referenced need to be available in
1334 if (LinkAlias(Dest, Src, ValueMap, ErrorMsg)) return true;
1336 // Update the initializers in the Dest module now that all globals that may
1337 // be referenced are in Dest.
1338 if (LinkGlobalInits(Dest, Src, ValueMap, ErrorMsg)) return true;
1340 // Link in the function bodies that are defined in the source module into the
1341 // DestModule. This consists basically of copying the function over and
1342 // fixing up references to values.
1343 if (LinkFunctionBodies(Dest, Src, ValueMap, ErrorMsg)) return true;
1345 // If there were any appending global variables, link them together now.
1346 if (LinkAppendingVars(Dest, AppendingVars, ErrorMsg)) return true;
1348 // Resolve all uses of aliases with aliasees
1349 if (ResolveAliases(Dest)) return true;
1351 // If the source library's module id is in the dependent library list of the
1352 // destination library, remove it since that module is now linked in.
1354 modId.set(Src->getModuleIdentifier());
1355 if (!modId.isEmpty())
1356 Dest->removeLibrary(modId.getBasename());