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 //===----------------------------------------------------------------------===//
14 #include "llvm/Linker.h"
15 #include "llvm/Constants.h"
16 #include "llvm/DerivedTypes.h"
17 #include "llvm/Instructions.h"
18 #include "llvm/Module.h"
19 #include "llvm/ADT/DenseSet.h"
20 #include "llvm/ADT/Optional.h"
21 #include "llvm/ADT/SetVector.h"
22 #include "llvm/ADT/SmallPtrSet.h"
23 #include "llvm/Support/Debug.h"
24 #include "llvm/Support/Path.h"
25 #include "llvm/Support/raw_ostream.h"
26 #include "llvm/Transforms/Utils/Cloning.h"
27 #include "llvm/Transforms/Utils/ValueMapper.h"
28 #include "llvm-c/Linker.h"
32 //===----------------------------------------------------------------------===//
33 // TypeMap implementation.
34 //===----------------------------------------------------------------------===//
37 class TypeMapTy : public ValueMapTypeRemapper {
38 /// MappedTypes - This is a mapping from a source type to a destination type
40 DenseMap<Type*, Type*> MappedTypes;
42 /// SpeculativeTypes - When checking to see if two subgraphs are isomorphic,
43 /// we speculatively add types to MappedTypes, but keep track of them here in
44 /// case we need to roll back.
45 SmallVector<Type*, 16> SpeculativeTypes;
47 /// SrcDefinitionsToResolve - This is a list of non-opaque structs in the
48 /// source module that are mapped to an opaque struct in the destination
50 SmallVector<StructType*, 16> SrcDefinitionsToResolve;
52 /// DstResolvedOpaqueTypes - This is the set of opaque types in the
53 /// destination modules who are getting a body from the source module.
54 SmallPtrSet<StructType*, 16> DstResolvedOpaqueTypes;
57 /// addTypeMapping - Indicate that the specified type in the destination
58 /// module is conceptually equivalent to the specified type in the source
60 void addTypeMapping(Type *DstTy, Type *SrcTy);
62 /// linkDefinedTypeBodies - Produce a body for an opaque type in the dest
63 /// module from a type definition in the source module.
64 void linkDefinedTypeBodies();
66 /// get - Return the mapped type to use for the specified input type from the
68 Type *get(Type *SrcTy);
70 FunctionType *get(FunctionType *T) {return cast<FunctionType>(get((Type*)T));}
72 /// dump - Dump out the type map for debugging purposes.
74 for (DenseMap<Type*, Type*>::const_iterator
75 I = MappedTypes.begin(), E = MappedTypes.end(); I != E; ++I) {
76 dbgs() << "TypeMap: ";
85 Type *getImpl(Type *T);
86 /// remapType - Implement the ValueMapTypeRemapper interface.
87 Type *remapType(Type *SrcTy) {
91 bool areTypesIsomorphic(Type *DstTy, Type *SrcTy);
95 void TypeMapTy::addTypeMapping(Type *DstTy, Type *SrcTy) {
96 Type *&Entry = MappedTypes[SrcTy];
104 // Check to see if these types are recursively isomorphic and establish a
105 // mapping between them if so.
106 if (!areTypesIsomorphic(DstTy, SrcTy)) {
107 // Oops, they aren't isomorphic. Just discard this request by rolling out
108 // any speculative mappings we've established.
109 for (unsigned i = 0, e = SpeculativeTypes.size(); i != e; ++i)
110 MappedTypes.erase(SpeculativeTypes[i]);
112 SpeculativeTypes.clear();
115 /// areTypesIsomorphic - Recursively walk this pair of types, returning true
116 /// if they are isomorphic, false if they are not.
117 bool TypeMapTy::areTypesIsomorphic(Type *DstTy, Type *SrcTy) {
118 // Two types with differing kinds are clearly not isomorphic.
119 if (DstTy->getTypeID() != SrcTy->getTypeID()) return false;
121 // If we have an entry in the MappedTypes table, then we have our answer.
122 Type *&Entry = MappedTypes[SrcTy];
124 return Entry == DstTy;
126 // Two identical types are clearly isomorphic. Remember this
127 // non-speculatively.
128 if (DstTy == SrcTy) {
133 // Okay, we have two types with identical kinds that we haven't seen before.
135 // If this is an opaque struct type, special case it.
136 if (StructType *SSTy = dyn_cast<StructType>(SrcTy)) {
137 // Mapping an opaque type to any struct, just keep the dest struct.
138 if (SSTy->isOpaque()) {
140 SpeculativeTypes.push_back(SrcTy);
144 // Mapping a non-opaque source type to an opaque dest. If this is the first
145 // type that we're mapping onto this destination type then we succeed. Keep
146 // the dest, but fill it in later. This doesn't need to be speculative. If
147 // this is the second (different) type that we're trying to map onto the
148 // same opaque type then we fail.
149 if (cast<StructType>(DstTy)->isOpaque()) {
150 // We can only map one source type onto the opaque destination type.
151 if (!DstResolvedOpaqueTypes.insert(cast<StructType>(DstTy)))
153 SrcDefinitionsToResolve.push_back(SSTy);
159 // If the number of subtypes disagree between the two types, then we fail.
160 if (SrcTy->getNumContainedTypes() != DstTy->getNumContainedTypes())
163 // Fail if any of the extra properties (e.g. array size) of the type disagree.
164 if (isa<IntegerType>(DstTy))
165 return false; // bitwidth disagrees.
166 if (PointerType *PT = dyn_cast<PointerType>(DstTy)) {
167 if (PT->getAddressSpace() != cast<PointerType>(SrcTy)->getAddressSpace())
170 } else if (FunctionType *FT = dyn_cast<FunctionType>(DstTy)) {
171 if (FT->isVarArg() != cast<FunctionType>(SrcTy)->isVarArg())
173 } else if (StructType *DSTy = dyn_cast<StructType>(DstTy)) {
174 StructType *SSTy = cast<StructType>(SrcTy);
175 if (DSTy->isLiteral() != SSTy->isLiteral() ||
176 DSTy->isPacked() != SSTy->isPacked())
178 } else if (ArrayType *DATy = dyn_cast<ArrayType>(DstTy)) {
179 if (DATy->getNumElements() != cast<ArrayType>(SrcTy)->getNumElements())
181 } else if (VectorType *DVTy = dyn_cast<VectorType>(DstTy)) {
182 if (DVTy->getNumElements() != cast<ArrayType>(SrcTy)->getNumElements())
186 // Otherwise, we speculate that these two types will line up and recursively
187 // check the subelements.
189 SpeculativeTypes.push_back(SrcTy);
191 for (unsigned i = 0, e = SrcTy->getNumContainedTypes(); i != e; ++i)
192 if (!areTypesIsomorphic(DstTy->getContainedType(i),
193 SrcTy->getContainedType(i)))
196 // If everything seems to have lined up, then everything is great.
200 /// linkDefinedTypeBodies - Produce a body for an opaque type in the dest
201 /// module from a type definition in the source module.
202 void TypeMapTy::linkDefinedTypeBodies() {
203 SmallVector<Type*, 16> Elements;
204 SmallString<16> TmpName;
206 // Note that processing entries in this loop (calling 'get') can add new
207 // entries to the SrcDefinitionsToResolve vector.
208 while (!SrcDefinitionsToResolve.empty()) {
209 StructType *SrcSTy = SrcDefinitionsToResolve.pop_back_val();
210 StructType *DstSTy = cast<StructType>(MappedTypes[SrcSTy]);
212 // TypeMap is a many-to-one mapping, if there were multiple types that
213 // provide a body for DstSTy then previous iterations of this loop may have
214 // already handled it. Just ignore this case.
215 if (!DstSTy->isOpaque()) continue;
216 assert(!SrcSTy->isOpaque() && "Not resolving a definition?");
218 // Map the body of the source type over to a new body for the dest type.
219 Elements.resize(SrcSTy->getNumElements());
220 for (unsigned i = 0, e = Elements.size(); i != e; ++i)
221 Elements[i] = getImpl(SrcSTy->getElementType(i));
223 DstSTy->setBody(Elements, SrcSTy->isPacked());
225 // If DstSTy has no name or has a longer name than STy, then viciously steal
227 if (!SrcSTy->hasName()) continue;
228 StringRef SrcName = SrcSTy->getName();
230 if (!DstSTy->hasName() || DstSTy->getName().size() > SrcName.size()) {
231 TmpName.insert(TmpName.end(), SrcName.begin(), SrcName.end());
233 DstSTy->setName(TmpName.str());
238 DstResolvedOpaqueTypes.clear();
241 /// get - Return the mapped type to use for the specified input type from the
243 Type *TypeMapTy::get(Type *Ty) {
244 Type *Result = getImpl(Ty);
246 // If this caused a reference to any struct type, resolve it before returning.
247 if (!SrcDefinitionsToResolve.empty())
248 linkDefinedTypeBodies();
252 /// getImpl - This is the recursive version of get().
253 Type *TypeMapTy::getImpl(Type *Ty) {
254 // If we already have an entry for this type, return it.
255 Type **Entry = &MappedTypes[Ty];
256 if (*Entry) return *Entry;
258 // If this is not a named struct type, then just map all of the elements and
259 // then rebuild the type from inside out.
260 if (!isa<StructType>(Ty) || cast<StructType>(Ty)->isLiteral()) {
261 // If there are no element types to map, then the type is itself. This is
262 // true for the anonymous {} struct, things like 'float', integers, etc.
263 if (Ty->getNumContainedTypes() == 0)
266 // Remap all of the elements, keeping track of whether any of them change.
267 bool AnyChange = false;
268 SmallVector<Type*, 4> ElementTypes;
269 ElementTypes.resize(Ty->getNumContainedTypes());
270 for (unsigned i = 0, e = Ty->getNumContainedTypes(); i != e; ++i) {
271 ElementTypes[i] = getImpl(Ty->getContainedType(i));
272 AnyChange |= ElementTypes[i] != Ty->getContainedType(i);
275 // If we found our type while recursively processing stuff, just use it.
276 Entry = &MappedTypes[Ty];
277 if (*Entry) return *Entry;
279 // If all of the element types mapped directly over, then the type is usable
284 // Otherwise, rebuild a modified type.
285 switch (Ty->getTypeID()) {
286 default: llvm_unreachable("unknown derived type to remap");
287 case Type::ArrayTyID:
288 return *Entry = ArrayType::get(ElementTypes[0],
289 cast<ArrayType>(Ty)->getNumElements());
290 case Type::VectorTyID:
291 return *Entry = VectorType::get(ElementTypes[0],
292 cast<VectorType>(Ty)->getNumElements());
293 case Type::PointerTyID:
294 return *Entry = PointerType::get(ElementTypes[0],
295 cast<PointerType>(Ty)->getAddressSpace());
296 case Type::FunctionTyID:
297 return *Entry = FunctionType::get(ElementTypes[0],
298 makeArrayRef(ElementTypes).slice(1),
299 cast<FunctionType>(Ty)->isVarArg());
300 case Type::StructTyID:
301 // Note that this is only reached for anonymous structs.
302 return *Entry = StructType::get(Ty->getContext(), ElementTypes,
303 cast<StructType>(Ty)->isPacked());
307 // Otherwise, this is an unmapped named struct. If the struct can be directly
308 // mapped over, just use it as-is. This happens in a case when the linked-in
309 // module has something like:
310 // %T = type {%T*, i32}
311 // @GV = global %T* null
312 // where T does not exist at all in the destination module.
314 // The other case we watch for is when the type is not in the destination
315 // module, but that it has to be rebuilt because it refers to something that
316 // is already mapped. For example, if the destination module has:
318 // and the source module has something like
319 // %A' = type { i32 }
320 // %B = type { %A'* }
321 // @GV = global %B* null
322 // then we want to create a new type: "%B = type { %A*}" and have it take the
323 // pristine "%B" name from the source module.
325 // To determine which case this is, we have to recursively walk the type graph
326 // speculating that we'll be able to reuse it unmodified. Only if this is
327 // safe would we map the entire thing over. Because this is an optimization,
328 // and is not required for the prettiness of the linked module, we just skip
329 // it and always rebuild a type here.
330 StructType *STy = cast<StructType>(Ty);
332 // If the type is opaque, we can just use it directly.
336 // Otherwise we create a new type and resolve its body later. This will be
337 // resolved by the top level of get().
338 SrcDefinitionsToResolve.push_back(STy);
339 StructType *DTy = StructType::create(STy->getContext());
340 DstResolvedOpaqueTypes.insert(DTy);
344 //===----------------------------------------------------------------------===//
345 // ModuleLinker implementation.
346 //===----------------------------------------------------------------------===//
349 /// ModuleLinker - This is an implementation class for the LinkModules
350 /// function, which is the entrypoint for this file.
356 /// ValueMap - Mapping of values from what they used to be in Src, to what
357 /// they are now in DstM. ValueToValueMapTy is a ValueMap, which involves
358 /// some overhead due to the use of Value handles which the Linker doesn't
359 /// actually need, but this allows us to reuse the ValueMapper code.
360 ValueToValueMapTy ValueMap;
362 struct AppendingVarInfo {
363 GlobalVariable *NewGV; // New aggregate global in dest module.
364 Constant *DstInit; // Old initializer from dest module.
365 Constant *SrcInit; // Old initializer from src module.
368 std::vector<AppendingVarInfo> AppendingVars;
370 unsigned Mode; // Mode to treat source module.
372 // Set of items not to link in from source.
373 SmallPtrSet<const Value*, 16> DoNotLinkFromSource;
375 // Vector of functions to lazily link in.
376 std::vector<Function*> LazilyLinkFunctions;
379 std::string ErrorMsg;
381 ModuleLinker(Module *dstM, Module *srcM, unsigned mode)
382 : DstM(dstM), SrcM(srcM), Mode(mode) { }
387 /// emitError - Helper method for setting a message and returning an error
389 bool emitError(const Twine &Message) {
390 ErrorMsg = Message.str();
394 /// getLinkageResult - This analyzes the two global values and determines
395 /// what the result will look like in the destination module.
396 bool getLinkageResult(GlobalValue *Dest, const GlobalValue *Src,
397 GlobalValue::LinkageTypes <,
398 GlobalValue::VisibilityTypes &Vis,
401 /// getLinkedToGlobal - Given a global in the source module, return the
402 /// global in the destination module that is being linked to, if any.
403 GlobalValue *getLinkedToGlobal(GlobalValue *SrcGV) {
404 // If the source has no name it can't link. If it has local linkage,
405 // there is no name match-up going on.
406 if (!SrcGV->hasName() || SrcGV->hasLocalLinkage())
409 // Otherwise see if we have a match in the destination module's symtab.
410 GlobalValue *DGV = DstM->getNamedValue(SrcGV->getName());
411 if (DGV == 0) return 0;
413 // If we found a global with the same name in the dest module, but it has
414 // internal linkage, we are really not doing any linkage here.
415 if (DGV->hasLocalLinkage())
418 // Otherwise, we do in fact link to the destination global.
422 void computeTypeMapping();
423 bool categorizeModuleFlagNodes(const NamedMDNode *ModFlags,
424 DenseMap<MDString*, MDNode*> &ErrorNode,
425 DenseMap<MDString*, MDNode*> &WarningNode,
426 DenseMap<MDString*, MDNode*> &OverrideNode,
428 SmallSetVector<MDNode*, 8> > &RequireNodes,
429 SmallSetVector<MDString*, 16> &SeenIDs);
431 bool linkAppendingVarProto(GlobalVariable *DstGV, GlobalVariable *SrcGV);
432 bool linkGlobalProto(GlobalVariable *SrcGV);
433 bool linkFunctionProto(Function *SrcF);
434 bool linkAliasProto(GlobalAlias *SrcA);
435 bool linkModuleFlagsMetadata();
437 void linkAppendingVarInit(const AppendingVarInfo &AVI);
438 void linkGlobalInits();
439 void linkFunctionBody(Function *Dst, Function *Src);
440 void linkAliasBodies();
441 void linkNamedMDNodes();
445 /// forceRenaming - The LLVM SymbolTable class autorenames globals that conflict
446 /// in the symbol table. This is good for all clients except for us. Go
447 /// through the trouble to force this back.
448 static void forceRenaming(GlobalValue *GV, StringRef Name) {
449 // If the global doesn't force its name or if it already has the right name,
450 // there is nothing for us to do.
451 if (GV->hasLocalLinkage() || GV->getName() == Name)
454 Module *M = GV->getParent();
456 // If there is a conflict, rename the conflict.
457 if (GlobalValue *ConflictGV = M->getNamedValue(Name)) {
458 GV->takeName(ConflictGV);
459 ConflictGV->setName(Name); // This will cause ConflictGV to get renamed
460 assert(ConflictGV->getName() != Name && "forceRenaming didn't work");
462 GV->setName(Name); // Force the name back
466 /// copyGVAttributes - copy additional attributes (those not needed to construct
467 /// a GlobalValue) from the SrcGV to the DestGV.
468 static void copyGVAttributes(GlobalValue *DestGV, const GlobalValue *SrcGV) {
469 // Use the maximum alignment, rather than just copying the alignment of SrcGV.
470 unsigned Alignment = std::max(DestGV->getAlignment(), SrcGV->getAlignment());
471 DestGV->copyAttributesFrom(SrcGV);
472 DestGV->setAlignment(Alignment);
474 forceRenaming(DestGV, SrcGV->getName());
477 static bool isLessConstraining(GlobalValue::VisibilityTypes a,
478 GlobalValue::VisibilityTypes b) {
479 if (a == GlobalValue::HiddenVisibility)
481 if (b == GlobalValue::HiddenVisibility)
483 if (a == GlobalValue::ProtectedVisibility)
485 if (b == GlobalValue::ProtectedVisibility)
490 /// getLinkageResult - This analyzes the two global values and determines what
491 /// the result will look like in the destination module. In particular, it
492 /// computes the resultant linkage type and visibility, computes whether the
493 /// global in the source should be copied over to the destination (replacing
494 /// the existing one), and computes whether this linkage is an error or not.
495 bool ModuleLinker::getLinkageResult(GlobalValue *Dest, const GlobalValue *Src,
496 GlobalValue::LinkageTypes <,
497 GlobalValue::VisibilityTypes &Vis,
499 assert(Dest && "Must have two globals being queried");
500 assert(!Src->hasLocalLinkage() &&
501 "If Src has internal linkage, Dest shouldn't be set!");
503 bool SrcIsDeclaration = Src->isDeclaration() && !Src->isMaterializable();
504 bool DestIsDeclaration = Dest->isDeclaration();
506 if (SrcIsDeclaration) {
507 // If Src is external or if both Src & Dest are external.. Just link the
508 // external globals, we aren't adding anything.
509 if (Src->hasDLLImportLinkage()) {
510 // If one of GVs has DLLImport linkage, result should be dllimport'ed.
511 if (DestIsDeclaration) {
513 LT = Src->getLinkage();
515 } else if (Dest->hasExternalWeakLinkage()) {
516 // If the Dest is weak, use the source linkage.
518 LT = Src->getLinkage();
521 LT = Dest->getLinkage();
523 } else if (DestIsDeclaration && !Dest->hasDLLImportLinkage()) {
524 // If Dest is external but Src is not:
526 LT = Src->getLinkage();
527 } else if (Src->isWeakForLinker()) {
528 // At this point we know that Dest has LinkOnce, External*, Weak, Common,
530 if (Dest->hasExternalWeakLinkage() ||
531 Dest->hasAvailableExternallyLinkage() ||
532 (Dest->hasLinkOnceLinkage() &&
533 (Src->hasWeakLinkage() || Src->hasCommonLinkage()))) {
535 LT = Src->getLinkage();
538 LT = Dest->getLinkage();
540 } else if (Dest->isWeakForLinker()) {
541 // At this point we know that Src has External* or DLL* linkage.
542 if (Src->hasExternalWeakLinkage()) {
544 LT = Dest->getLinkage();
547 LT = GlobalValue::ExternalLinkage;
550 assert((Dest->hasExternalLinkage() || Dest->hasDLLImportLinkage() ||
551 Dest->hasDLLExportLinkage() || Dest->hasExternalWeakLinkage()) &&
552 (Src->hasExternalLinkage() || Src->hasDLLImportLinkage() ||
553 Src->hasDLLExportLinkage() || Src->hasExternalWeakLinkage()) &&
554 "Unexpected linkage type!");
555 return emitError("Linking globals named '" + Src->getName() +
556 "': symbol multiply defined!");
559 // Compute the visibility. We follow the rules in the System V Application
561 Vis = isLessConstraining(Src->getVisibility(), Dest->getVisibility()) ?
562 Dest->getVisibility() : Src->getVisibility();
566 /// computeTypeMapping - Loop over all of the linked values to compute type
567 /// mappings. For example, if we link "extern Foo *x" and "Foo *x = NULL", then
568 /// we have two struct types 'Foo' but one got renamed when the module was
569 /// loaded into the same LLVMContext.
570 void ModuleLinker::computeTypeMapping() {
571 // Incorporate globals.
572 for (Module::global_iterator I = SrcM->global_begin(),
573 E = SrcM->global_end(); I != E; ++I) {
574 GlobalValue *DGV = getLinkedToGlobal(I);
575 if (DGV == 0) continue;
577 if (!DGV->hasAppendingLinkage() || !I->hasAppendingLinkage()) {
578 TypeMap.addTypeMapping(DGV->getType(), I->getType());
582 // Unify the element type of appending arrays.
583 ArrayType *DAT = cast<ArrayType>(DGV->getType()->getElementType());
584 ArrayType *SAT = cast<ArrayType>(I->getType()->getElementType());
585 TypeMap.addTypeMapping(DAT->getElementType(), SAT->getElementType());
588 // Incorporate functions.
589 for (Module::iterator I = SrcM->begin(), E = SrcM->end(); I != E; ++I) {
590 if (GlobalValue *DGV = getLinkedToGlobal(I))
591 TypeMap.addTypeMapping(DGV->getType(), I->getType());
594 // Incorporate types by name, scanning all the types in the source module.
595 // At this point, the destination module may have a type "%foo = { i32 }" for
596 // example. When the source module got loaded into the same LLVMContext, if
597 // it had the same type, it would have been renamed to "%foo.42 = { i32 }".
598 std::vector<StructType*> SrcStructTypes;
599 SrcM->findUsedStructTypes(SrcStructTypes, true);
600 SmallPtrSet<StructType*, 32> SrcStructTypesSet(SrcStructTypes.begin(),
601 SrcStructTypes.end());
603 std::vector<StructType*> DstStructTypes;
604 DstM->findUsedStructTypes(DstStructTypes, true);
605 SmallPtrSet<StructType*, 32> DstStructTypesSet(DstStructTypes.begin(),
606 DstStructTypes.end());
608 for (unsigned i = 0, e = SrcStructTypes.size(); i != e; ++i) {
609 StructType *ST = SrcStructTypes[i];
610 if (!ST->hasName()) continue;
612 // Check to see if there is a dot in the name followed by a digit.
613 size_t DotPos = ST->getName().rfind('.');
614 if (DotPos == 0 || DotPos == StringRef::npos ||
615 ST->getName().back() == '.' || !isdigit(ST->getName()[DotPos+1]))
618 // Check to see if the destination module has a struct with the prefix name.
619 if (StructType *DST = DstM->getTypeByName(ST->getName().substr(0, DotPos)))
620 // Don't use it if this actually came from the source module. They're in
621 // the same LLVMContext after all. Also don't use it unless the type is
622 // actually used in the destination module. This can happen in situations
627 // %Z = type { %A } %B = type { %C.1 }
628 // %A = type { %B.1, [7 x i8] } %C.1 = type { i8* }
629 // %B.1 = type { %C } %A.2 = type { %B.3, [5 x i8] }
630 // %C = type { i8* } %B.3 = type { %C.1 }
632 // When we link Module B with Module A, the '%B' in Module B is
633 // used. However, that would then use '%C.1'. But when we process '%C.1',
634 // we prefer to take the '%C' version. So we are then left with both
635 // '%C.1' and '%C' being used for the same types. This leads to some
636 // variables using one type and some using the other.
637 if (!SrcStructTypesSet.count(DST) && DstStructTypesSet.count(DST))
638 TypeMap.addTypeMapping(DST, ST);
641 // Don't bother incorporating aliases, they aren't generally typed well.
643 // Now that we have discovered all of the type equivalences, get a body for
644 // any 'opaque' types in the dest module that are now resolved.
645 TypeMap.linkDefinedTypeBodies();
648 /// linkAppendingVarProto - If there were any appending global variables, link
649 /// them together now. Return true on error.
650 bool ModuleLinker::linkAppendingVarProto(GlobalVariable *DstGV,
651 GlobalVariable *SrcGV) {
653 if (!SrcGV->hasAppendingLinkage() || !DstGV->hasAppendingLinkage())
654 return emitError("Linking globals named '" + SrcGV->getName() +
655 "': can only link appending global with another appending global!");
657 ArrayType *DstTy = cast<ArrayType>(DstGV->getType()->getElementType());
659 cast<ArrayType>(TypeMap.get(SrcGV->getType()->getElementType()));
660 Type *EltTy = DstTy->getElementType();
662 // Check to see that they two arrays agree on type.
663 if (EltTy != SrcTy->getElementType())
664 return emitError("Appending variables with different element types!");
665 if (DstGV->isConstant() != SrcGV->isConstant())
666 return emitError("Appending variables linked with different const'ness!");
668 if (DstGV->getAlignment() != SrcGV->getAlignment())
670 "Appending variables with different alignment need to be linked!");
672 if (DstGV->getVisibility() != SrcGV->getVisibility())
674 "Appending variables with different visibility need to be linked!");
676 if (DstGV->getSection() != SrcGV->getSection())
678 "Appending variables with different section name need to be linked!");
680 uint64_t NewSize = DstTy->getNumElements() + SrcTy->getNumElements();
681 ArrayType *NewType = ArrayType::get(EltTy, NewSize);
683 // Create the new global variable.
685 new GlobalVariable(*DstGV->getParent(), NewType, SrcGV->isConstant(),
686 DstGV->getLinkage(), /*init*/0, /*name*/"", DstGV,
687 DstGV->isThreadLocal(),
688 DstGV->getType()->getAddressSpace());
690 // Propagate alignment, visibility and section info.
691 copyGVAttributes(NG, DstGV);
693 AppendingVarInfo AVI;
695 AVI.DstInit = DstGV->getInitializer();
696 AVI.SrcInit = SrcGV->getInitializer();
697 AppendingVars.push_back(AVI);
699 // Replace any uses of the two global variables with uses of the new
701 ValueMap[SrcGV] = ConstantExpr::getBitCast(NG, TypeMap.get(SrcGV->getType()));
703 DstGV->replaceAllUsesWith(ConstantExpr::getBitCast(NG, DstGV->getType()));
704 DstGV->eraseFromParent();
706 // Track the source variable so we don't try to link it.
707 DoNotLinkFromSource.insert(SrcGV);
712 /// linkGlobalProto - Loop through the global variables in the src module and
713 /// merge them into the dest module.
714 bool ModuleLinker::linkGlobalProto(GlobalVariable *SGV) {
715 GlobalValue *DGV = getLinkedToGlobal(SGV);
716 llvm::Optional<GlobalValue::VisibilityTypes> NewVisibility;
719 // Concatenation of appending linkage variables is magic and handled later.
720 if (DGV->hasAppendingLinkage() || SGV->hasAppendingLinkage())
721 return linkAppendingVarProto(cast<GlobalVariable>(DGV), SGV);
723 // Determine whether linkage of these two globals follows the source
724 // module's definition or the destination module's definition.
725 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage;
726 GlobalValue::VisibilityTypes NV;
727 bool LinkFromSrc = false;
728 if (getLinkageResult(DGV, SGV, NewLinkage, NV, LinkFromSrc))
732 // If we're not linking from the source, then keep the definition that we
735 // Special case for const propagation.
736 if (GlobalVariable *DGVar = dyn_cast<GlobalVariable>(DGV))
737 if (DGVar->isDeclaration() && SGV->isConstant() && !DGVar->isConstant())
738 DGVar->setConstant(true);
740 // Set calculated linkage and visibility.
741 DGV->setLinkage(NewLinkage);
742 DGV->setVisibility(*NewVisibility);
744 // Make sure to remember this mapping.
745 ValueMap[SGV] = ConstantExpr::getBitCast(DGV,TypeMap.get(SGV->getType()));
747 // Track the source global so that we don't attempt to copy it over when
748 // processing global initializers.
749 DoNotLinkFromSource.insert(SGV);
755 // No linking to be performed or linking from the source: simply create an
756 // identical version of the symbol over in the dest module... the
757 // initializer will be filled in later by LinkGlobalInits.
758 GlobalVariable *NewDGV =
759 new GlobalVariable(*DstM, TypeMap.get(SGV->getType()->getElementType()),
760 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
761 SGV->getName(), /*insertbefore*/0,
762 SGV->isThreadLocal(),
763 SGV->getType()->getAddressSpace());
764 // Propagate alignment, visibility and section info.
765 copyGVAttributes(NewDGV, SGV);
767 NewDGV->setVisibility(*NewVisibility);
770 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDGV, DGV->getType()));
771 DGV->eraseFromParent();
774 // Make sure to remember this mapping.
775 ValueMap[SGV] = NewDGV;
779 /// linkFunctionProto - Link the function in the source module into the
780 /// destination module if needed, setting up mapping information.
781 bool ModuleLinker::linkFunctionProto(Function *SF) {
782 GlobalValue *DGV = getLinkedToGlobal(SF);
783 llvm::Optional<GlobalValue::VisibilityTypes> NewVisibility;
786 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage;
787 bool LinkFromSrc = false;
788 GlobalValue::VisibilityTypes NV;
789 if (getLinkageResult(DGV, SF, NewLinkage, NV, LinkFromSrc))
794 // Set calculated linkage
795 DGV->setLinkage(NewLinkage);
796 DGV->setVisibility(*NewVisibility);
798 // Make sure to remember this mapping.
799 ValueMap[SF] = ConstantExpr::getBitCast(DGV, TypeMap.get(SF->getType()));
801 // Track the function from the source module so we don't attempt to remap
803 DoNotLinkFromSource.insert(SF);
809 // If there is no linkage to be performed or we are linking from the source,
811 Function *NewDF = Function::Create(TypeMap.get(SF->getFunctionType()),
812 SF->getLinkage(), SF->getName(), DstM);
813 copyGVAttributes(NewDF, SF);
815 NewDF->setVisibility(*NewVisibility);
818 // Any uses of DF need to change to NewDF, with cast.
819 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDF, DGV->getType()));
820 DGV->eraseFromParent();
822 // Internal, LO_ODR, or LO linkage - stick in set to ignore and lazily link.
823 if (SF->hasLocalLinkage() || SF->hasLinkOnceLinkage() ||
824 SF->hasAvailableExternallyLinkage()) {
825 DoNotLinkFromSource.insert(SF);
826 LazilyLinkFunctions.push_back(SF);
830 ValueMap[SF] = NewDF;
834 /// LinkAliasProto - Set up prototypes for any aliases that come over from the
836 bool ModuleLinker::linkAliasProto(GlobalAlias *SGA) {
837 GlobalValue *DGV = getLinkedToGlobal(SGA);
838 llvm::Optional<GlobalValue::VisibilityTypes> NewVisibility;
841 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage;
842 GlobalValue::VisibilityTypes NV;
843 bool LinkFromSrc = false;
844 if (getLinkageResult(DGV, SGA, NewLinkage, NV, LinkFromSrc))
849 // Set calculated linkage.
850 DGV->setLinkage(NewLinkage);
851 DGV->setVisibility(*NewVisibility);
853 // Make sure to remember this mapping.
854 ValueMap[SGA] = ConstantExpr::getBitCast(DGV,TypeMap.get(SGA->getType()));
856 // Track the alias from the source module so we don't attempt to remap it.
857 DoNotLinkFromSource.insert(SGA);
863 // If there is no linkage to be performed or we're linking from the source,
865 GlobalAlias *NewDA = new GlobalAlias(TypeMap.get(SGA->getType()),
866 SGA->getLinkage(), SGA->getName(),
868 copyGVAttributes(NewDA, SGA);
870 NewDA->setVisibility(*NewVisibility);
873 // Any uses of DGV need to change to NewDA, with cast.
874 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDA, DGV->getType()));
875 DGV->eraseFromParent();
878 ValueMap[SGA] = NewDA;
882 static void getArrayElements(Constant *C, SmallVectorImpl<Constant*> &Dest) {
883 unsigned NumElements = cast<ArrayType>(C->getType())->getNumElements();
885 for (unsigned i = 0; i != NumElements; ++i)
886 Dest.push_back(C->getAggregateElement(i));
889 void ModuleLinker::linkAppendingVarInit(const AppendingVarInfo &AVI) {
890 // Merge the initializer.
891 SmallVector<Constant*, 16> Elements;
892 getArrayElements(AVI.DstInit, Elements);
894 Constant *SrcInit = MapValue(AVI.SrcInit, ValueMap, RF_None, &TypeMap);
895 getArrayElements(SrcInit, Elements);
897 ArrayType *NewType = cast<ArrayType>(AVI.NewGV->getType()->getElementType());
898 AVI.NewGV->setInitializer(ConstantArray::get(NewType, Elements));
901 /// linkGlobalInits - Update the initializers in the Dest module now that all
902 /// globals that may be referenced are in Dest.
903 void ModuleLinker::linkGlobalInits() {
904 // Loop over all of the globals in the src module, mapping them over as we go
905 for (Module::const_global_iterator I = SrcM->global_begin(),
906 E = SrcM->global_end(); I != E; ++I) {
908 // Only process initialized GV's or ones not already in dest.
909 if (!I->hasInitializer() || DoNotLinkFromSource.count(I)) continue;
911 // Grab destination global variable.
912 GlobalVariable *DGV = cast<GlobalVariable>(ValueMap[I]);
913 // Figure out what the initializer looks like in the dest module.
914 DGV->setInitializer(MapValue(I->getInitializer(), ValueMap,
919 /// linkFunctionBody - Copy the source function over into the dest function and
920 /// fix up references to values. At this point we know that Dest is an external
921 /// function, and that Src is not.
922 void ModuleLinker::linkFunctionBody(Function *Dst, Function *Src) {
923 assert(Src && Dst && Dst->isDeclaration() && !Src->isDeclaration());
925 // Go through and convert function arguments over, remembering the mapping.
926 Function::arg_iterator DI = Dst->arg_begin();
927 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end();
929 DI->setName(I->getName()); // Copy the name over.
931 // Add a mapping to our mapping.
935 if (Mode == Linker::DestroySource) {
936 // Splice the body of the source function into the dest function.
937 Dst->getBasicBlockList().splice(Dst->end(), Src->getBasicBlockList());
939 // At this point, all of the instructions and values of the function are now
940 // copied over. The only problem is that they are still referencing values in
941 // the Source function as operands. Loop through all of the operands of the
942 // functions and patch them up to point to the local versions.
943 for (Function::iterator BB = Dst->begin(), BE = Dst->end(); BB != BE; ++BB)
944 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
945 RemapInstruction(I, ValueMap, RF_IgnoreMissingEntries, &TypeMap);
948 // Clone the body of the function into the dest function.
949 SmallVector<ReturnInst*, 8> Returns; // Ignore returns.
950 CloneFunctionInto(Dst, Src, ValueMap, false, Returns, "", NULL, &TypeMap);
953 // There is no need to map the arguments anymore.
954 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end();
960 /// linkAliasBodies - Insert all of the aliases in Src into the Dest module.
961 void ModuleLinker::linkAliasBodies() {
962 for (Module::alias_iterator I = SrcM->alias_begin(), E = SrcM->alias_end();
964 if (DoNotLinkFromSource.count(I))
966 if (Constant *Aliasee = I->getAliasee()) {
967 GlobalAlias *DA = cast<GlobalAlias>(ValueMap[I]);
968 DA->setAliasee(MapValue(Aliasee, ValueMap, RF_None, &TypeMap));
973 /// linkNamedMDNodes - Insert all of the named MDNodes in Src into the Dest
975 void ModuleLinker::linkNamedMDNodes() {
976 const NamedMDNode *SrcModFlags = SrcM->getModuleFlagsMetadata();
977 for (Module::const_named_metadata_iterator I = SrcM->named_metadata_begin(),
978 E = SrcM->named_metadata_end(); I != E; ++I) {
979 // Don't link module flags here. Do them separately.
980 if (&*I == SrcModFlags) continue;
981 NamedMDNode *DestNMD = DstM->getOrInsertNamedMetadata(I->getName());
982 // Add Src elements into Dest node.
983 for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i)
984 DestNMD->addOperand(MapValue(I->getOperand(i), ValueMap,
989 /// categorizeModuleFlagNodes - Categorize the module flags according to their
990 /// type: Error, Warning, Override, and Require.
992 categorizeModuleFlagNodes(const NamedMDNode *ModFlags,
993 DenseMap<MDString*, MDNode*> &ErrorNode,
994 DenseMap<MDString*, MDNode*> &WarningNode,
995 DenseMap<MDString*, MDNode*> &OverrideNode,
997 SmallSetVector<MDNode*, 8> > &RequireNodes,
998 SmallSetVector<MDString*, 16> &SeenIDs) {
1001 for (unsigned I = 0, E = ModFlags->getNumOperands(); I != E; ++I) {
1002 MDNode *Op = ModFlags->getOperand(I);
1003 assert(Op->getNumOperands() == 3 && "Invalid module flag metadata!");
1004 assert(isa<ConstantInt>(Op->getOperand(0)) &&
1005 "Module flag's first operand must be an integer!");
1006 assert(isa<MDString>(Op->getOperand(1)) &&
1007 "Module flag's second operand must be an MDString!");
1009 ConstantInt *Behavior = cast<ConstantInt>(Op->getOperand(0));
1010 MDString *ID = cast<MDString>(Op->getOperand(1));
1011 Value *Val = Op->getOperand(2);
1012 switch (Behavior->getZExtValue()) {
1014 assert(false && "Invalid behavior in module flag metadata!");
1016 case Module::Error: {
1017 MDNode *&ErrNode = ErrorNode[ID];
1018 if (!ErrNode) ErrNode = Op;
1019 if (ErrNode->getOperand(2) != Val)
1020 HasErr = emitError("linking module flags '" + ID->getString() +
1021 "': IDs have conflicting values");
1024 case Module::Warning: {
1025 MDNode *&WarnNode = WarningNode[ID];
1026 if (!WarnNode) WarnNode = Op;
1027 if (WarnNode->getOperand(2) != Val)
1028 errs() << "WARNING: linking module flags '" << ID->getString()
1029 << "': IDs have conflicting values";
1032 case Module::Require: RequireNodes[ID].insert(Op); break;
1033 case Module::Override: {
1034 MDNode *&OvrNode = OverrideNode[ID];
1035 if (!OvrNode) OvrNode = Op;
1036 if (OvrNode->getOperand(2) != Val)
1037 HasErr = emitError("linking module flags '" + ID->getString() +
1038 "': IDs have conflicting override values");
1049 /// linkModuleFlagsMetadata - Merge the linker flags in Src into the Dest
1051 bool ModuleLinker::linkModuleFlagsMetadata() {
1052 const NamedMDNode *SrcModFlags = SrcM->getModuleFlagsMetadata();
1053 if (!SrcModFlags) return false;
1055 NamedMDNode *DstModFlags = DstM->getOrInsertModuleFlagsMetadata();
1057 // If the destination module doesn't have module flags yet, then just copy
1058 // over the source module's flags.
1059 if (DstModFlags->getNumOperands() == 0) {
1060 for (unsigned I = 0, E = SrcModFlags->getNumOperands(); I != E; ++I)
1061 DstModFlags->addOperand(SrcModFlags->getOperand(I));
1066 bool HasErr = false;
1068 // Otherwise, we have to merge them based on their behaviors. First,
1069 // categorize all of the nodes in the modules' module flags. If an error or
1070 // warning occurs, then emit the appropriate message(s).
1071 DenseMap<MDString*, MDNode*> ErrorNode;
1072 DenseMap<MDString*, MDNode*> WarningNode;
1073 DenseMap<MDString*, MDNode*> OverrideNode;
1074 DenseMap<MDString*, SmallSetVector<MDNode*, 8> > RequireNodes;
1075 SmallSetVector<MDString*, 16> SeenIDs;
1077 HasErr |= categorizeModuleFlagNodes(SrcModFlags, ErrorNode, WarningNode,
1078 OverrideNode, RequireNodes, SeenIDs);
1079 HasErr |= categorizeModuleFlagNodes(DstModFlags, ErrorNode, WarningNode,
1080 OverrideNode, RequireNodes, SeenIDs);
1082 // Check that there isn't both an error and warning node for a flag.
1083 for (SmallSetVector<MDString*, 16>::iterator
1084 I = SeenIDs.begin(), E = SeenIDs.end(); I != E; ++I) {
1086 if (ErrorNode[ID] && WarningNode[ID])
1087 HasErr = emitError("linking module flags '" + ID->getString() +
1088 "': IDs have conflicting behaviors");
1091 // Early exit if we had an error.
1092 if (HasErr) return true;
1094 // Get the destination's module flags ready for new operands.
1095 DstModFlags->dropAllReferences();
1097 // Add all of the module flags to the destination module.
1098 DenseMap<MDString*, SmallVector<MDNode*, 4> > AddedNodes;
1099 for (SmallSetVector<MDString*, 16>::iterator
1100 I = SeenIDs.begin(), E = SeenIDs.end(); I != E; ++I) {
1102 if (OverrideNode[ID]) {
1103 DstModFlags->addOperand(OverrideNode[ID]);
1104 AddedNodes[ID].push_back(OverrideNode[ID]);
1105 } else if (ErrorNode[ID]) {
1106 DstModFlags->addOperand(ErrorNode[ID]);
1107 AddedNodes[ID].push_back(ErrorNode[ID]);
1108 } else if (WarningNode[ID]) {
1109 DstModFlags->addOperand(WarningNode[ID]);
1110 AddedNodes[ID].push_back(WarningNode[ID]);
1113 for (SmallSetVector<MDNode*, 8>::iterator
1114 II = RequireNodes[ID].begin(), IE = RequireNodes[ID].end();
1116 DstModFlags->addOperand(*II);
1119 // Now check that all of the requirements have been satisfied.
1120 for (SmallSetVector<MDString*, 16>::iterator
1121 I = SeenIDs.begin(), E = SeenIDs.end(); I != E; ++I) {
1123 SmallSetVector<MDNode*, 8> &Set = RequireNodes[ID];
1125 for (SmallSetVector<MDNode*, 8>::iterator
1126 II = Set.begin(), IE = Set.end(); II != IE; ++II) {
1128 assert(isa<MDNode>(Node->getOperand(2)) &&
1129 "Module flag's third operand must be an MDNode!");
1130 MDNode *Val = cast<MDNode>(Node->getOperand(2));
1132 MDString *ReqID = cast<MDString>(Val->getOperand(0));
1133 Value *ReqVal = Val->getOperand(1);
1135 bool HasValue = false;
1136 for (SmallVectorImpl<MDNode*>::iterator
1137 RI = AddedNodes[ReqID].begin(), RE = AddedNodes[ReqID].end();
1139 MDNode *ReqNode = *RI;
1140 if (ReqNode->getOperand(2) == ReqVal) {
1147 HasErr = emitError("linking module flags '" + ReqID->getString() +
1148 "': does not have the required value");
1155 bool ModuleLinker::run() {
1156 assert(DstM && "Null destination module");
1157 assert(SrcM && "Null source module");
1159 // Inherit the target data from the source module if the destination module
1160 // doesn't have one already.
1161 if (DstM->getDataLayout().empty() && !SrcM->getDataLayout().empty())
1162 DstM->setDataLayout(SrcM->getDataLayout());
1164 // Copy the target triple from the source to dest if the dest's is empty.
1165 if (DstM->getTargetTriple().empty() && !SrcM->getTargetTriple().empty())
1166 DstM->setTargetTriple(SrcM->getTargetTriple());
1168 if (!SrcM->getDataLayout().empty() && !DstM->getDataLayout().empty() &&
1169 SrcM->getDataLayout() != DstM->getDataLayout())
1170 errs() << "WARNING: Linking two modules of different data layouts!\n";
1171 if (!SrcM->getTargetTriple().empty() &&
1172 DstM->getTargetTriple() != SrcM->getTargetTriple()) {
1173 errs() << "WARNING: Linking two modules of different target triples: ";
1174 if (!SrcM->getModuleIdentifier().empty())
1175 errs() << SrcM->getModuleIdentifier() << ": ";
1176 errs() << "'" << SrcM->getTargetTriple() << "' and '"
1177 << DstM->getTargetTriple() << "'\n";
1180 // Append the module inline asm string.
1181 if (!SrcM->getModuleInlineAsm().empty()) {
1182 if (DstM->getModuleInlineAsm().empty())
1183 DstM->setModuleInlineAsm(SrcM->getModuleInlineAsm());
1185 DstM->setModuleInlineAsm(DstM->getModuleInlineAsm()+"\n"+
1186 SrcM->getModuleInlineAsm());
1189 // Update the destination module's dependent libraries list with the libraries
1190 // from the source module. There's no opportunity for duplicates here as the
1191 // Module ensures that duplicate insertions are discarded.
1192 for (Module::lib_iterator SI = SrcM->lib_begin(), SE = SrcM->lib_end();
1194 DstM->addLibrary(*SI);
1196 // If the source library's module id is in the dependent library list of the
1197 // destination library, remove it since that module is now linked in.
1198 StringRef ModuleId = SrcM->getModuleIdentifier();
1199 if (!ModuleId.empty())
1200 DstM->removeLibrary(sys::path::stem(ModuleId));
1202 // Loop over all of the linked values to compute type mappings.
1203 computeTypeMapping();
1205 // Insert all of the globals in src into the DstM module... without linking
1206 // initializers (which could refer to functions not yet mapped over).
1207 for (Module::global_iterator I = SrcM->global_begin(),
1208 E = SrcM->global_end(); I != E; ++I)
1209 if (linkGlobalProto(I))
1212 // Link the functions together between the two modules, without doing function
1213 // bodies... this just adds external function prototypes to the DstM
1214 // function... We do this so that when we begin processing function bodies,
1215 // all of the global values that may be referenced are available in our
1217 for (Module::iterator I = SrcM->begin(), E = SrcM->end(); I != E; ++I)
1218 if (linkFunctionProto(I))
1221 // If there were any aliases, link them now.
1222 for (Module::alias_iterator I = SrcM->alias_begin(),
1223 E = SrcM->alias_end(); I != E; ++I)
1224 if (linkAliasProto(I))
1227 for (unsigned i = 0, e = AppendingVars.size(); i != e; ++i)
1228 linkAppendingVarInit(AppendingVars[i]);
1230 // Update the initializers in the DstM module now that all globals that may
1231 // be referenced are in DstM.
1234 // Link in the function bodies that are defined in the source module into
1236 for (Module::iterator SF = SrcM->begin(), E = SrcM->end(); SF != E; ++SF) {
1237 // Skip if not linking from source.
1238 if (DoNotLinkFromSource.count(SF)) continue;
1240 // Skip if no body (function is external) or materialize.
1241 if (SF->isDeclaration()) {
1242 if (!SF->isMaterializable())
1244 if (SF->Materialize(&ErrorMsg))
1248 linkFunctionBody(cast<Function>(ValueMap[SF]), SF);
1249 SF->Dematerialize();
1252 // Resolve all uses of aliases with aliasees.
1255 // Remap all of the named MDNodes in Src into the DstM module. We do this
1256 // after linking GlobalValues so that MDNodes that reference GlobalValues
1257 // are properly remapped.
1260 // Merge the module flags into the DstM module.
1261 if (linkModuleFlagsMetadata())
1264 // Process vector of lazily linked in functions.
1265 bool LinkedInAnyFunctions;
1267 LinkedInAnyFunctions = false;
1269 for(std::vector<Function*>::iterator I = LazilyLinkFunctions.begin(),
1270 E = LazilyLinkFunctions.end(); I != E; ++I) {
1275 Function *DF = cast<Function>(ValueMap[SF]);
1277 if (!DF->use_empty()) {
1279 // Materialize if necessary.
1280 if (SF->isDeclaration()) {
1281 if (!SF->isMaterializable())
1283 if (SF->Materialize(&ErrorMsg))
1287 // Link in function body.
1288 linkFunctionBody(DF, SF);
1289 SF->Dematerialize();
1291 // "Remove" from vector by setting the element to 0.
1294 // Set flag to indicate we may have more functions to lazily link in
1295 // since we linked in a function.
1296 LinkedInAnyFunctions = true;
1299 } while (LinkedInAnyFunctions);
1301 // Remove any prototypes of functions that were not actually linked in.
1302 for(std::vector<Function*>::iterator I = LazilyLinkFunctions.begin(),
1303 E = LazilyLinkFunctions.end(); I != E; ++I) {
1308 Function *DF = cast<Function>(ValueMap[SF]);
1309 if (DF->use_empty())
1310 DF->eraseFromParent();
1313 // Now that all of the types from the source are used, resolve any structs
1314 // copied over to the dest that didn't exist there.
1315 TypeMap.linkDefinedTypeBodies();
1320 //===----------------------------------------------------------------------===//
1321 // LinkModules entrypoint.
1322 //===----------------------------------------------------------------------===//
1324 /// LinkModules - This function links two modules together, with the resulting
1325 /// left module modified to be the composite of the two input modules. If an
1326 /// error occurs, true is returned and ErrorMsg (if not null) is set to indicate
1327 /// the problem. Upon failure, the Dest module could be in a modified state,
1328 /// and shouldn't be relied on to be consistent.
1329 bool Linker::LinkModules(Module *Dest, Module *Src, unsigned Mode,
1330 std::string *ErrorMsg) {
1331 ModuleLinker TheLinker(Dest, Src, Mode);
1332 if (TheLinker.run()) {
1333 if (ErrorMsg) *ErrorMsg = TheLinker.ErrorMsg;
1340 //===----------------------------------------------------------------------===//
1342 //===----------------------------------------------------------------------===//
1344 LLVMBool LLVMLinkModules(LLVMModuleRef Dest, LLVMModuleRef Src,
1345 LLVMLinkerMode Mode, char **OutMessages) {
1346 std::string Messages;
1347 LLVMBool Result = Linker::LinkModules(unwrap(Dest), unwrap(Src),
1348 Mode, OutMessages? &Messages : 0);
1350 *OutMessages = strdup(Messages.c_str());