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-c/Linker.h"
16 #include "llvm/ADT/Optional.h"
17 #include "llvm/ADT/SetVector.h"
18 #include "llvm/ADT/SmallString.h"
19 #include "llvm/IR/Constants.h"
20 #include "llvm/IR/Module.h"
21 #include "llvm/IR/TypeFinder.h"
22 #include "llvm/Support/Debug.h"
23 #include "llvm/Support/raw_ostream.h"
24 #include "llvm/Transforms/Utils/Cloning.h"
27 //===----------------------------------------------------------------------===//
28 // TypeMap implementation.
29 //===----------------------------------------------------------------------===//
32 typedef SmallPtrSet<StructType*, 32> TypeSet;
34 class TypeMapTy : public ValueMapTypeRemapper {
35 /// MappedTypes - This is a mapping from a source type to a destination type
37 DenseMap<Type*, Type*> MappedTypes;
39 /// SpeculativeTypes - When checking to see if two subgraphs are isomorphic,
40 /// we speculatively add types to MappedTypes, but keep track of them here in
41 /// case we need to roll back.
42 SmallVector<Type*, 16> SpeculativeTypes;
44 /// SrcDefinitionsToResolve - This is a list of non-opaque structs in the
45 /// source module that are mapped to an opaque struct in the destination
47 SmallVector<StructType*, 16> SrcDefinitionsToResolve;
49 /// DstResolvedOpaqueTypes - This is the set of opaque types in the
50 /// destination modules who are getting a body from the source module.
51 SmallPtrSet<StructType*, 16> DstResolvedOpaqueTypes;
54 TypeMapTy(TypeSet &Set) : DstStructTypesSet(Set) {}
56 TypeSet &DstStructTypesSet;
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<VectorType>(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.
333 if (STy->isOpaque()) {
334 // A named structure type from src module is used. Add it to the Set of
335 // identified structs in the destination module.
336 DstStructTypesSet.insert(STy);
340 // Otherwise we create a new type and resolve its body later. This will be
341 // resolved by the top level of get().
342 SrcDefinitionsToResolve.push_back(STy);
343 StructType *DTy = StructType::create(STy->getContext());
344 // A new identified structure type was created. Add it to the set of
345 // identified structs in the destination module.
346 DstStructTypesSet.insert(DTy);
347 DstResolvedOpaqueTypes.insert(DTy);
351 //===----------------------------------------------------------------------===//
352 // ModuleLinker implementation.
353 //===----------------------------------------------------------------------===//
356 /// ModuleLinker - This is an implementation class for the LinkModules
357 /// function, which is the entrypoint for this file.
363 /// ValueMap - Mapping of values from what they used to be in Src, to what
364 /// they are now in DstM. ValueToValueMapTy is a ValueMap, which involves
365 /// some overhead due to the use of Value handles which the Linker doesn't
366 /// actually need, but this allows us to reuse the ValueMapper code.
367 ValueToValueMapTy ValueMap;
369 struct AppendingVarInfo {
370 GlobalVariable *NewGV; // New aggregate global in dest module.
371 Constant *DstInit; // Old initializer from dest module.
372 Constant *SrcInit; // Old initializer from src module.
375 std::vector<AppendingVarInfo> AppendingVars;
377 unsigned Mode; // Mode to treat source module.
379 // Set of items not to link in from source.
380 SmallPtrSet<const Value*, 16> DoNotLinkFromSource;
382 // Vector of functions to lazily link in.
383 std::vector<Function*> LazilyLinkFunctions;
386 std::string ErrorMsg;
388 ModuleLinker(Module *dstM, TypeSet &Set, Module *srcM, unsigned mode)
389 : DstM(dstM), SrcM(srcM), TypeMap(Set), Mode(mode) { }
394 /// emitError - Helper method for setting a message and returning an error
396 bool emitError(const Twine &Message) {
397 ErrorMsg = Message.str();
401 /// getLinkageResult - This analyzes the two global values and determines
402 /// what the result will look like in the destination module.
403 bool getLinkageResult(GlobalValue *Dest, const GlobalValue *Src,
404 GlobalValue::LinkageTypes <,
405 GlobalValue::VisibilityTypes &Vis,
408 /// getLinkedToGlobal - Given a global in the source module, return the
409 /// global in the destination module that is being linked to, if any.
410 GlobalValue *getLinkedToGlobal(GlobalValue *SrcGV) {
411 // If the source has no name it can't link. If it has local linkage,
412 // there is no name match-up going on.
413 if (!SrcGV->hasName() || SrcGV->hasLocalLinkage())
416 // Otherwise see if we have a match in the destination module's symtab.
417 GlobalValue *DGV = DstM->getNamedValue(SrcGV->getName());
418 if (DGV == 0) return 0;
420 // If we found a global with the same name in the dest module, but it has
421 // internal linkage, we are really not doing any linkage here.
422 if (DGV->hasLocalLinkage())
425 // Otherwise, we do in fact link to the destination global.
429 void computeTypeMapping();
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 TypeFinder SrcStructTypes;
599 SrcStructTypes.run(*SrcM, true);
600 SmallPtrSet<StructType*, 32> SrcStructTypesSet(SrcStructTypes.begin(),
601 SrcStructTypes.end());
603 for (unsigned i = 0, e = SrcStructTypes.size(); i != e; ++i) {
604 StructType *ST = SrcStructTypes[i];
605 if (!ST->hasName()) continue;
607 // Check to see if there is a dot in the name followed by a digit.
608 size_t DotPos = ST->getName().rfind('.');
609 if (DotPos == 0 || DotPos == StringRef::npos ||
610 ST->getName().back() == '.' ||
611 !isdigit(static_cast<unsigned char>(ST->getName()[DotPos+1])))
614 // Check to see if the destination module has a struct with the prefix name.
615 if (StructType *DST = DstM->getTypeByName(ST->getName().substr(0, DotPos)))
616 // Don't use it if this actually came from the source module. They're in
617 // the same LLVMContext after all. Also don't use it unless the type is
618 // actually used in the destination module. This can happen in situations
623 // %Z = type { %A } %B = type { %C.1 }
624 // %A = type { %B.1, [7 x i8] } %C.1 = type { i8* }
625 // %B.1 = type { %C } %A.2 = type { %B.3, [5 x i8] }
626 // %C = type { i8* } %B.3 = type { %C.1 }
628 // When we link Module B with Module A, the '%B' in Module B is
629 // used. However, that would then use '%C.1'. But when we process '%C.1',
630 // we prefer to take the '%C' version. So we are then left with both
631 // '%C.1' and '%C' being used for the same types. This leads to some
632 // variables using one type and some using the other.
633 if (!SrcStructTypesSet.count(DST) && TypeMap.DstStructTypesSet.count(DST))
634 TypeMap.addTypeMapping(DST, ST);
637 // Don't bother incorporating aliases, they aren't generally typed well.
639 // Now that we have discovered all of the type equivalences, get a body for
640 // any 'opaque' types in the dest module that are now resolved.
641 TypeMap.linkDefinedTypeBodies();
644 /// linkAppendingVarProto - If there were any appending global variables, link
645 /// them together now. Return true on error.
646 bool ModuleLinker::linkAppendingVarProto(GlobalVariable *DstGV,
647 GlobalVariable *SrcGV) {
649 if (!SrcGV->hasAppendingLinkage() || !DstGV->hasAppendingLinkage())
650 return emitError("Linking globals named '" + SrcGV->getName() +
651 "': can only link appending global with another appending global!");
653 ArrayType *DstTy = cast<ArrayType>(DstGV->getType()->getElementType());
655 cast<ArrayType>(TypeMap.get(SrcGV->getType()->getElementType()));
656 Type *EltTy = DstTy->getElementType();
658 // Check to see that they two arrays agree on type.
659 if (EltTy != SrcTy->getElementType())
660 return emitError("Appending variables with different element types!");
661 if (DstGV->isConstant() != SrcGV->isConstant())
662 return emitError("Appending variables linked with different const'ness!");
664 if (DstGV->getAlignment() != SrcGV->getAlignment())
666 "Appending variables with different alignment need to be linked!");
668 if (DstGV->getVisibility() != SrcGV->getVisibility())
670 "Appending variables with different visibility need to be linked!");
672 if (DstGV->getSection() != SrcGV->getSection())
674 "Appending variables with different section name need to be linked!");
676 uint64_t NewSize = DstTy->getNumElements() + SrcTy->getNumElements();
677 ArrayType *NewType = ArrayType::get(EltTy, NewSize);
679 // Create the new global variable.
681 new GlobalVariable(*DstGV->getParent(), NewType, SrcGV->isConstant(),
682 DstGV->getLinkage(), /*init*/0, /*name*/"", DstGV,
683 DstGV->getThreadLocalMode(),
684 DstGV->getType()->getAddressSpace());
686 // Propagate alignment, visibility and section info.
687 copyGVAttributes(NG, DstGV);
689 AppendingVarInfo AVI;
691 AVI.DstInit = DstGV->getInitializer();
692 AVI.SrcInit = SrcGV->getInitializer();
693 AppendingVars.push_back(AVI);
695 // Replace any uses of the two global variables with uses of the new
697 ValueMap[SrcGV] = ConstantExpr::getBitCast(NG, TypeMap.get(SrcGV->getType()));
699 DstGV->replaceAllUsesWith(ConstantExpr::getBitCast(NG, DstGV->getType()));
700 DstGV->eraseFromParent();
702 // Track the source variable so we don't try to link it.
703 DoNotLinkFromSource.insert(SrcGV);
708 /// linkGlobalProto - Loop through the global variables in the src module and
709 /// merge them into the dest module.
710 bool ModuleLinker::linkGlobalProto(GlobalVariable *SGV) {
711 GlobalValue *DGV = getLinkedToGlobal(SGV);
712 llvm::Optional<GlobalValue::VisibilityTypes> NewVisibility;
715 // Concatenation of appending linkage variables is magic and handled later.
716 if (DGV->hasAppendingLinkage() || SGV->hasAppendingLinkage())
717 return linkAppendingVarProto(cast<GlobalVariable>(DGV), SGV);
719 // Determine whether linkage of these two globals follows the source
720 // module's definition or the destination module's definition.
721 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage;
722 GlobalValue::VisibilityTypes NV;
723 bool LinkFromSrc = false;
724 if (getLinkageResult(DGV, SGV, NewLinkage, NV, LinkFromSrc))
728 // If we're not linking from the source, then keep the definition that we
731 // Special case for const propagation.
732 if (GlobalVariable *DGVar = dyn_cast<GlobalVariable>(DGV))
733 if (DGVar->isDeclaration() && SGV->isConstant() && !DGVar->isConstant())
734 DGVar->setConstant(true);
736 // Set calculated linkage and visibility.
737 DGV->setLinkage(NewLinkage);
738 DGV->setVisibility(*NewVisibility);
740 // Make sure to remember this mapping.
741 ValueMap[SGV] = ConstantExpr::getBitCast(DGV,TypeMap.get(SGV->getType()));
743 // Track the source global so that we don't attempt to copy it over when
744 // processing global initializers.
745 DoNotLinkFromSource.insert(SGV);
751 // No linking to be performed or linking from the source: simply create an
752 // identical version of the symbol over in the dest module... the
753 // initializer will be filled in later by LinkGlobalInits.
754 GlobalVariable *NewDGV =
755 new GlobalVariable(*DstM, TypeMap.get(SGV->getType()->getElementType()),
756 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
757 SGV->getName(), /*insertbefore*/0,
758 SGV->getThreadLocalMode(),
759 SGV->getType()->getAddressSpace());
760 // Propagate alignment, visibility and section info.
761 copyGVAttributes(NewDGV, SGV);
763 NewDGV->setVisibility(*NewVisibility);
766 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDGV, DGV->getType()));
767 DGV->eraseFromParent();
770 // Make sure to remember this mapping.
771 ValueMap[SGV] = NewDGV;
775 /// linkFunctionProto - Link the function in the source module into the
776 /// destination module if needed, setting up mapping information.
777 bool ModuleLinker::linkFunctionProto(Function *SF) {
778 GlobalValue *DGV = getLinkedToGlobal(SF);
779 llvm::Optional<GlobalValue::VisibilityTypes> NewVisibility;
782 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage;
783 bool LinkFromSrc = false;
784 GlobalValue::VisibilityTypes NV;
785 if (getLinkageResult(DGV, SF, NewLinkage, NV, LinkFromSrc))
790 // Set calculated linkage
791 DGV->setLinkage(NewLinkage);
792 DGV->setVisibility(*NewVisibility);
794 // Make sure to remember this mapping.
795 ValueMap[SF] = ConstantExpr::getBitCast(DGV, TypeMap.get(SF->getType()));
797 // Track the function from the source module so we don't attempt to remap
799 DoNotLinkFromSource.insert(SF);
805 // If there is no linkage to be performed or we are linking from the source,
807 Function *NewDF = Function::Create(TypeMap.get(SF->getFunctionType()),
808 SF->getLinkage(), SF->getName(), DstM);
809 copyGVAttributes(NewDF, SF);
811 NewDF->setVisibility(*NewVisibility);
814 // Any uses of DF need to change to NewDF, with cast.
815 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDF, DGV->getType()));
816 DGV->eraseFromParent();
818 // Internal, LO_ODR, or LO linkage - stick in set to ignore and lazily link.
819 if (SF->hasLocalLinkage() || SF->hasLinkOnceLinkage() ||
820 SF->hasAvailableExternallyLinkage()) {
821 DoNotLinkFromSource.insert(SF);
822 LazilyLinkFunctions.push_back(SF);
826 ValueMap[SF] = NewDF;
830 /// LinkAliasProto - Set up prototypes for any aliases that come over from the
832 bool ModuleLinker::linkAliasProto(GlobalAlias *SGA) {
833 GlobalValue *DGV = getLinkedToGlobal(SGA);
834 llvm::Optional<GlobalValue::VisibilityTypes> NewVisibility;
837 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage;
838 GlobalValue::VisibilityTypes NV;
839 bool LinkFromSrc = false;
840 if (getLinkageResult(DGV, SGA, NewLinkage, NV, LinkFromSrc))
845 // Set calculated linkage.
846 DGV->setLinkage(NewLinkage);
847 DGV->setVisibility(*NewVisibility);
849 // Make sure to remember this mapping.
850 ValueMap[SGA] = ConstantExpr::getBitCast(DGV,TypeMap.get(SGA->getType()));
852 // Track the alias from the source module so we don't attempt to remap it.
853 DoNotLinkFromSource.insert(SGA);
859 // If there is no linkage to be performed or we're linking from the source,
861 GlobalAlias *NewDA = new GlobalAlias(TypeMap.get(SGA->getType()),
862 SGA->getLinkage(), SGA->getName(),
864 copyGVAttributes(NewDA, SGA);
866 NewDA->setVisibility(*NewVisibility);
869 // Any uses of DGV need to change to NewDA, with cast.
870 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDA, DGV->getType()));
871 DGV->eraseFromParent();
874 ValueMap[SGA] = NewDA;
878 static void getArrayElements(Constant *C, SmallVectorImpl<Constant*> &Dest) {
879 unsigned NumElements = cast<ArrayType>(C->getType())->getNumElements();
881 for (unsigned i = 0; i != NumElements; ++i)
882 Dest.push_back(C->getAggregateElement(i));
885 void ModuleLinker::linkAppendingVarInit(const AppendingVarInfo &AVI) {
886 // Merge the initializer.
887 SmallVector<Constant*, 16> Elements;
888 getArrayElements(AVI.DstInit, Elements);
890 Constant *SrcInit = MapValue(AVI.SrcInit, ValueMap, RF_None, &TypeMap);
891 getArrayElements(SrcInit, Elements);
893 ArrayType *NewType = cast<ArrayType>(AVI.NewGV->getType()->getElementType());
894 AVI.NewGV->setInitializer(ConstantArray::get(NewType, Elements));
897 /// linkGlobalInits - Update the initializers in the Dest module now that all
898 /// globals that may be referenced are in Dest.
899 void ModuleLinker::linkGlobalInits() {
900 // Loop over all of the globals in the src module, mapping them over as we go
901 for (Module::const_global_iterator I = SrcM->global_begin(),
902 E = SrcM->global_end(); I != E; ++I) {
904 // Only process initialized GV's or ones not already in dest.
905 if (!I->hasInitializer() || DoNotLinkFromSource.count(I)) continue;
907 // Grab destination global variable.
908 GlobalVariable *DGV = cast<GlobalVariable>(ValueMap[I]);
909 // Figure out what the initializer looks like in the dest module.
910 DGV->setInitializer(MapValue(I->getInitializer(), ValueMap,
915 /// linkFunctionBody - Copy the source function over into the dest function and
916 /// fix up references to values. At this point we know that Dest is an external
917 /// function, and that Src is not.
918 void ModuleLinker::linkFunctionBody(Function *Dst, Function *Src) {
919 assert(Src && Dst && Dst->isDeclaration() && !Src->isDeclaration());
921 // Go through and convert function arguments over, remembering the mapping.
922 Function::arg_iterator DI = Dst->arg_begin();
923 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end();
925 DI->setName(I->getName()); // Copy the name over.
927 // Add a mapping to our mapping.
931 if (Mode == Linker::DestroySource) {
932 // Splice the body of the source function into the dest function.
933 Dst->getBasicBlockList().splice(Dst->end(), Src->getBasicBlockList());
935 // At this point, all of the instructions and values of the function are now
936 // copied over. The only problem is that they are still referencing values in
937 // the Source function as operands. Loop through all of the operands of the
938 // functions and patch them up to point to the local versions.
939 for (Function::iterator BB = Dst->begin(), BE = Dst->end(); BB != BE; ++BB)
940 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
941 RemapInstruction(I, ValueMap, RF_IgnoreMissingEntries, &TypeMap);
944 // Clone the body of the function into the dest function.
945 SmallVector<ReturnInst*, 8> Returns; // Ignore returns.
946 CloneFunctionInto(Dst, Src, ValueMap, false, Returns, "", NULL, &TypeMap);
949 // There is no need to map the arguments anymore.
950 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end();
956 /// linkAliasBodies - Insert all of the aliases in Src into the Dest module.
957 void ModuleLinker::linkAliasBodies() {
958 for (Module::alias_iterator I = SrcM->alias_begin(), E = SrcM->alias_end();
960 if (DoNotLinkFromSource.count(I))
962 if (Constant *Aliasee = I->getAliasee()) {
963 GlobalAlias *DA = cast<GlobalAlias>(ValueMap[I]);
964 DA->setAliasee(MapValue(Aliasee, ValueMap, RF_None, &TypeMap));
969 /// linkNamedMDNodes - Insert all of the named MDNodes in Src into the Dest
971 void ModuleLinker::linkNamedMDNodes() {
972 const NamedMDNode *SrcModFlags = SrcM->getModuleFlagsMetadata();
973 for (Module::const_named_metadata_iterator I = SrcM->named_metadata_begin(),
974 E = SrcM->named_metadata_end(); I != E; ++I) {
975 // Don't link module flags here. Do them separately.
976 if (&*I == SrcModFlags) continue;
977 NamedMDNode *DestNMD = DstM->getOrInsertNamedMetadata(I->getName());
978 // Add Src elements into Dest node.
979 for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i)
980 DestNMD->addOperand(MapValue(I->getOperand(i), ValueMap,
985 /// linkModuleFlagsMetadata - Merge the linker flags in Src into the Dest
987 bool ModuleLinker::linkModuleFlagsMetadata() {
988 // If the source module has no module flags, we are done.
989 const NamedMDNode *SrcModFlags = SrcM->getModuleFlagsMetadata();
990 if (!SrcModFlags) return false;
992 // If the destination module doesn't have module flags yet, then just copy
993 // over the source module's flags.
994 NamedMDNode *DstModFlags = DstM->getOrInsertModuleFlagsMetadata();
995 if (DstModFlags->getNumOperands() == 0) {
996 for (unsigned I = 0, E = SrcModFlags->getNumOperands(); I != E; ++I)
997 DstModFlags->addOperand(SrcModFlags->getOperand(I));
1002 // First build a map of the existing module flags and requirements.
1003 DenseMap<MDString*, MDNode*> Flags;
1004 SmallSetVector<MDNode*, 16> Requirements;
1005 for (unsigned I = 0, E = DstModFlags->getNumOperands(); I != E; ++I) {
1006 MDNode *Op = DstModFlags->getOperand(I);
1007 ConstantInt *Behavior = cast<ConstantInt>(Op->getOperand(0));
1008 MDString *ID = cast<MDString>(Op->getOperand(1));
1010 if (Behavior->getZExtValue() == Module::Require) {
1011 Requirements.insert(cast<MDNode>(Op->getOperand(2)));
1017 // Merge in the flags from the source module, and also collect its set of
1019 bool HasErr = false;
1020 for (unsigned I = 0, E = SrcModFlags->getNumOperands(); I != E; ++I) {
1021 MDNode *SrcOp = SrcModFlags->getOperand(I);
1022 ConstantInt *SrcBehavior = cast<ConstantInt>(SrcOp->getOperand(0));
1023 MDString *ID = cast<MDString>(SrcOp->getOperand(1));
1024 MDNode *DstOp = Flags.lookup(ID);
1025 unsigned SrcBehaviorValue = SrcBehavior->getZExtValue();
1027 // If this is a requirement, add it and continue.
1028 if (SrcBehaviorValue == Module::Require) {
1029 // If the destination module does not already have this requirement, add
1031 if (Requirements.insert(cast<MDNode>(SrcOp->getOperand(2)))) {
1032 DstModFlags->addOperand(SrcOp);
1037 // If there is no existing flag with this ID, just add it.
1040 DstModFlags->addOperand(SrcOp);
1044 // Otherwise, perform a merge.
1045 ConstantInt *DstBehavior = cast<ConstantInt>(DstOp->getOperand(0));
1046 unsigned DstBehaviorValue = DstBehavior->getZExtValue();
1048 // If either flag has override behavior, handle it first.
1049 if (DstBehaviorValue == Module::Override) {
1050 // Diagnose inconsistent flags which both have override behavior.
1051 if (SrcBehaviorValue == Module::Override &&
1052 SrcOp->getOperand(2) != DstOp->getOperand(2)) {
1053 HasErr |= emitError("linking module flags '" + ID->getString() +
1054 "': IDs have conflicting override values");
1057 } else if (SrcBehaviorValue == Module::Override) {
1058 // Update the destination flag to that of the source.
1059 DstOp->replaceOperandWith(0, SrcBehavior);
1060 DstOp->replaceOperandWith(2, SrcOp->getOperand(2));
1064 // Diagnose inconsistent merge behavior types.
1065 if (SrcBehaviorValue != DstBehaviorValue) {
1066 HasErr |= emitError("linking module flags '" + ID->getString() +
1067 "': IDs have conflicting behaviors");
1071 // Perform the merge for standard behavior types.
1072 switch (SrcBehaviorValue) {
1073 case Module::Require:
1074 case Module::Override: assert(0 && "not possible"); break;
1075 case Module::Error: {
1076 // Emit an error if the values differ.
1077 if (SrcOp->getOperand(2) != DstOp->getOperand(2)) {
1078 HasErr |= emitError("linking module flags '" + ID->getString() +
1079 "': IDs have conflicting values");
1083 case Module::Warning: {
1084 // Emit a warning if the values differ.
1085 if (SrcOp->getOperand(2) != DstOp->getOperand(2)) {
1086 errs() << "WARNING: linking module flags '" << ID->getString()
1087 << "': IDs have conflicting values";
1091 case Module::Append: {
1092 MDNode *DstValue = cast<MDNode>(DstOp->getOperand(2));
1093 MDNode *SrcValue = cast<MDNode>(SrcOp->getOperand(2));
1094 unsigned NumOps = DstValue->getNumOperands() + SrcValue->getNumOperands();
1095 Value **VP, **Values = VP = new Value*[NumOps];
1096 for (unsigned i = 0, e = DstValue->getNumOperands(); i != e; ++i, ++VP)
1097 *VP = DstValue->getOperand(i);
1098 for (unsigned i = 0, e = SrcValue->getNumOperands(); i != e; ++i, ++VP)
1099 *VP = SrcValue->getOperand(i);
1100 DstOp->replaceOperandWith(2, MDNode::get(DstM->getContext(),
1101 ArrayRef<Value*>(Values,
1106 case Module::AppendUnique: {
1107 SmallSetVector<Value*, 16> Elts;
1108 MDNode *DstValue = cast<MDNode>(DstOp->getOperand(2));
1109 MDNode *SrcValue = cast<MDNode>(SrcOp->getOperand(2));
1110 for (unsigned i = 0, e = DstValue->getNumOperands(); i != e; ++i)
1111 Elts.insert(DstValue->getOperand(i));
1112 for (unsigned i = 0, e = SrcValue->getNumOperands(); i != e; ++i)
1113 Elts.insert(SrcValue->getOperand(i));
1114 DstOp->replaceOperandWith(2, MDNode::get(DstM->getContext(),
1115 ArrayRef<Value*>(Elts.begin(),
1122 // Check all of the requirements.
1123 for (unsigned I = 0, E = Requirements.size(); I != E; ++I) {
1124 MDNode *Requirement = Requirements[I];
1125 MDString *Flag = cast<MDString>(Requirement->getOperand(0));
1126 Value *ReqValue = Requirement->getOperand(1);
1128 MDNode *Op = Flags[Flag];
1129 if (!Op || Op->getOperand(2) != ReqValue) {
1130 HasErr |= emitError("linking module flags '" + Flag->getString() +
1131 "': does not have the required value");
1139 bool ModuleLinker::run() {
1140 assert(DstM && "Null destination module");
1141 assert(SrcM && "Null source module");
1143 // Inherit the target data from the source module if the destination module
1144 // doesn't have one already.
1145 if (DstM->getDataLayout().empty() && !SrcM->getDataLayout().empty())
1146 DstM->setDataLayout(SrcM->getDataLayout());
1148 // Copy the target triple from the source to dest if the dest's is empty.
1149 if (DstM->getTargetTriple().empty() && !SrcM->getTargetTriple().empty())
1150 DstM->setTargetTriple(SrcM->getTargetTriple());
1152 if (!SrcM->getDataLayout().empty() && !DstM->getDataLayout().empty() &&
1153 SrcM->getDataLayout() != DstM->getDataLayout())
1154 errs() << "WARNING: Linking two modules of different data layouts!\n";
1155 if (!SrcM->getTargetTriple().empty() &&
1156 DstM->getTargetTriple() != SrcM->getTargetTriple()) {
1157 errs() << "WARNING: Linking two modules of different target triples: ";
1158 if (!SrcM->getModuleIdentifier().empty())
1159 errs() << SrcM->getModuleIdentifier() << ": ";
1160 errs() << "'" << SrcM->getTargetTriple() << "' and '"
1161 << DstM->getTargetTriple() << "'\n";
1164 // Append the module inline asm string.
1165 if (!SrcM->getModuleInlineAsm().empty()) {
1166 if (DstM->getModuleInlineAsm().empty())
1167 DstM->setModuleInlineAsm(SrcM->getModuleInlineAsm());
1169 DstM->setModuleInlineAsm(DstM->getModuleInlineAsm()+"\n"+
1170 SrcM->getModuleInlineAsm());
1173 // Loop over all of the linked values to compute type mappings.
1174 computeTypeMapping();
1176 // Insert all of the globals in src into the DstM module... without linking
1177 // initializers (which could refer to functions not yet mapped over).
1178 for (Module::global_iterator I = SrcM->global_begin(),
1179 E = SrcM->global_end(); I != E; ++I)
1180 if (linkGlobalProto(I))
1183 // Link the functions together between the two modules, without doing function
1184 // bodies... this just adds external function prototypes to the DstM
1185 // function... We do this so that when we begin processing function bodies,
1186 // all of the global values that may be referenced are available in our
1188 for (Module::iterator I = SrcM->begin(), E = SrcM->end(); I != E; ++I)
1189 if (linkFunctionProto(I))
1192 // If there were any aliases, link them now.
1193 for (Module::alias_iterator I = SrcM->alias_begin(),
1194 E = SrcM->alias_end(); I != E; ++I)
1195 if (linkAliasProto(I))
1198 for (unsigned i = 0, e = AppendingVars.size(); i != e; ++i)
1199 linkAppendingVarInit(AppendingVars[i]);
1201 // Update the initializers in the DstM module now that all globals that may
1202 // be referenced are in DstM.
1205 // Link in the function bodies that are defined in the source module into
1207 for (Module::iterator SF = SrcM->begin(), E = SrcM->end(); SF != E; ++SF) {
1208 // Skip if not linking from source.
1209 if (DoNotLinkFromSource.count(SF)) continue;
1211 // Skip if no body (function is external) or materialize.
1212 if (SF->isDeclaration()) {
1213 if (!SF->isMaterializable())
1215 if (SF->Materialize(&ErrorMsg))
1219 linkFunctionBody(cast<Function>(ValueMap[SF]), SF);
1220 SF->Dematerialize();
1223 // Resolve all uses of aliases with aliasees.
1226 // Remap all of the named MDNodes in Src into the DstM module. We do this
1227 // after linking GlobalValues so that MDNodes that reference GlobalValues
1228 // are properly remapped.
1231 // Merge the module flags into the DstM module.
1232 if (linkModuleFlagsMetadata())
1235 // Process vector of lazily linked in functions.
1236 bool LinkedInAnyFunctions;
1238 LinkedInAnyFunctions = false;
1240 for(std::vector<Function*>::iterator I = LazilyLinkFunctions.begin(),
1241 E = LazilyLinkFunctions.end(); I != E; ++I) {
1246 Function *DF = cast<Function>(ValueMap[SF]);
1248 if (!DF->use_empty()) {
1250 // Materialize if necessary.
1251 if (SF->isDeclaration()) {
1252 if (!SF->isMaterializable())
1254 if (SF->Materialize(&ErrorMsg))
1258 // Link in function body.
1259 linkFunctionBody(DF, SF);
1260 SF->Dematerialize();
1262 // "Remove" from vector by setting the element to 0.
1265 // Set flag to indicate we may have more functions to lazily link in
1266 // since we linked in a function.
1267 LinkedInAnyFunctions = true;
1270 } while (LinkedInAnyFunctions);
1272 // Remove any prototypes of functions that were not actually linked in.
1273 for(std::vector<Function*>::iterator I = LazilyLinkFunctions.begin(),
1274 E = LazilyLinkFunctions.end(); I != E; ++I) {
1279 Function *DF = cast<Function>(ValueMap[SF]);
1280 if (DF->use_empty())
1281 DF->eraseFromParent();
1284 // Now that all of the types from the source are used, resolve any structs
1285 // copied over to the dest that didn't exist there.
1286 TypeMap.linkDefinedTypeBodies();
1291 Linker::Linker(Module *M) : Composite(M) {
1292 TypeFinder StructTypes;
1293 StructTypes.run(*M, true);
1294 IdentifiedStructTypes.insert(StructTypes.begin(), StructTypes.end());
1300 bool Linker::linkInModule(Module *Src, unsigned Mode, std::string *ErrorMsg) {
1301 ModuleLinker TheLinker(Composite, IdentifiedStructTypes, Src, Mode);
1302 if (TheLinker.run()) {
1304 *ErrorMsg = TheLinker.ErrorMsg;
1310 //===----------------------------------------------------------------------===//
1311 // LinkModules entrypoint.
1312 //===----------------------------------------------------------------------===//
1314 /// LinkModules - This function links two modules together, with the resulting
1315 /// Dest module modified to be the composite of the two input modules. If an
1316 /// error occurs, true is returned and ErrorMsg (if not null) is set to indicate
1317 /// the problem. Upon failure, the Dest module could be in a modified state,
1318 /// and shouldn't be relied on to be consistent.
1319 bool Linker::LinkModules(Module *Dest, Module *Src, unsigned Mode,
1320 std::string *ErrorMsg) {
1322 return L.linkInModule(Src, Mode, ErrorMsg);
1325 //===----------------------------------------------------------------------===//
1327 //===----------------------------------------------------------------------===//
1329 LLVMBool LLVMLinkModules(LLVMModuleRef Dest, LLVMModuleRef Src,
1330 LLVMLinkerMode Mode, char **OutMessages) {
1331 std::string Messages;
1332 LLVMBool Result = Linker::LinkModules(unwrap(Dest), unwrap(Src),
1333 Mode, OutMessages? &Messages : 0);
1335 *OutMessages = strdup(Messages.c_str());