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"
28 //===----------------------------------------------------------------------===//
29 // TypeMap implementation.
30 //===----------------------------------------------------------------------===//
33 typedef SmallPtrSet<StructType*, 32> TypeSet;
35 class TypeMapTy : public ValueMapTypeRemapper {
36 /// MappedTypes - This is a mapping from a source type to a destination type
38 DenseMap<Type*, Type*> MappedTypes;
40 /// SpeculativeTypes - When checking to see if two subgraphs are isomorphic,
41 /// we speculatively add types to MappedTypes, but keep track of them here in
42 /// case we need to roll back.
43 SmallVector<Type*, 16> SpeculativeTypes;
45 /// SrcDefinitionsToResolve - This is a list of non-opaque structs in the
46 /// source module that are mapped to an opaque struct in the destination
48 SmallVector<StructType*, 16> SrcDefinitionsToResolve;
50 /// DstResolvedOpaqueTypes - This is the set of opaque types in the
51 /// destination modules who are getting a body from the source module.
52 SmallPtrSet<StructType*, 16> DstResolvedOpaqueTypes;
55 TypeMapTy(TypeSet &Set) : DstStructTypesSet(Set) {}
57 TypeSet &DstStructTypesSet;
58 /// addTypeMapping - Indicate that the specified type in the destination
59 /// module is conceptually equivalent to the specified type in the source
61 void addTypeMapping(Type *DstTy, Type *SrcTy);
63 /// linkDefinedTypeBodies - Produce a body for an opaque type in the dest
64 /// module from a type definition in the source module.
65 void linkDefinedTypeBodies();
67 /// get - Return the mapped type to use for the specified input type from the
69 Type *get(Type *SrcTy);
71 FunctionType *get(FunctionType *T) {return cast<FunctionType>(get((Type*)T));}
73 /// dump - Dump out the type map for debugging purposes.
75 for (DenseMap<Type*, Type*>::const_iterator
76 I = MappedTypes.begin(), E = MappedTypes.end(); I != E; ++I) {
77 dbgs() << "TypeMap: ";
86 Type *getImpl(Type *T);
87 /// remapType - Implement the ValueMapTypeRemapper interface.
88 Type *remapType(Type *SrcTy) {
92 bool areTypesIsomorphic(Type *DstTy, Type *SrcTy);
96 void TypeMapTy::addTypeMapping(Type *DstTy, Type *SrcTy) {
97 Type *&Entry = MappedTypes[SrcTy];
100 if (DstTy == SrcTy) {
105 // Check to see if these types are recursively isomorphic and establish a
106 // mapping between them if so.
107 if (!areTypesIsomorphic(DstTy, SrcTy)) {
108 // Oops, they aren't isomorphic. Just discard this request by rolling out
109 // any speculative mappings we've established.
110 for (unsigned i = 0, e = SpeculativeTypes.size(); i != e; ++i)
111 MappedTypes.erase(SpeculativeTypes[i]);
113 SpeculativeTypes.clear();
116 /// areTypesIsomorphic - Recursively walk this pair of types, returning true
117 /// if they are isomorphic, false if they are not.
118 bool TypeMapTy::areTypesIsomorphic(Type *DstTy, Type *SrcTy) {
119 // Two types with differing kinds are clearly not isomorphic.
120 if (DstTy->getTypeID() != SrcTy->getTypeID()) return false;
122 // If we have an entry in the MappedTypes table, then we have our answer.
123 Type *&Entry = MappedTypes[SrcTy];
125 return Entry == DstTy;
127 // Two identical types are clearly isomorphic. Remember this
128 // non-speculatively.
129 if (DstTy == SrcTy) {
134 // Okay, we have two types with identical kinds that we haven't seen before.
136 // If this is an opaque struct type, special case it.
137 if (StructType *SSTy = dyn_cast<StructType>(SrcTy)) {
138 // Mapping an opaque type to any struct, just keep the dest struct.
139 if (SSTy->isOpaque()) {
141 SpeculativeTypes.push_back(SrcTy);
145 // Mapping a non-opaque source type to an opaque dest. If this is the first
146 // type that we're mapping onto this destination type then we succeed. Keep
147 // the dest, but fill it in later. This doesn't need to be speculative. If
148 // this is the second (different) type that we're trying to map onto the
149 // same opaque type then we fail.
150 if (cast<StructType>(DstTy)->isOpaque()) {
151 // We can only map one source type onto the opaque destination type.
152 if (!DstResolvedOpaqueTypes.insert(cast<StructType>(DstTy)))
154 SrcDefinitionsToResolve.push_back(SSTy);
160 // If the number of subtypes disagree between the two types, then we fail.
161 if (SrcTy->getNumContainedTypes() != DstTy->getNumContainedTypes())
164 // Fail if any of the extra properties (e.g. array size) of the type disagree.
165 if (isa<IntegerType>(DstTy))
166 return false; // bitwidth disagrees.
167 if (PointerType *PT = dyn_cast<PointerType>(DstTy)) {
168 if (PT->getAddressSpace() != cast<PointerType>(SrcTy)->getAddressSpace())
171 } else if (FunctionType *FT = dyn_cast<FunctionType>(DstTy)) {
172 if (FT->isVarArg() != cast<FunctionType>(SrcTy)->isVarArg())
174 } else if (StructType *DSTy = dyn_cast<StructType>(DstTy)) {
175 StructType *SSTy = cast<StructType>(SrcTy);
176 if (DSTy->isLiteral() != SSTy->isLiteral() ||
177 DSTy->isPacked() != SSTy->isPacked())
179 } else if (ArrayType *DATy = dyn_cast<ArrayType>(DstTy)) {
180 if (DATy->getNumElements() != cast<ArrayType>(SrcTy)->getNumElements())
182 } else if (VectorType *DVTy = dyn_cast<VectorType>(DstTy)) {
183 if (DVTy->getNumElements() != cast<VectorType>(SrcTy)->getNumElements())
187 // Otherwise, we speculate that these two types will line up and recursively
188 // check the subelements.
190 SpeculativeTypes.push_back(SrcTy);
192 for (unsigned i = 0, e = SrcTy->getNumContainedTypes(); i != e; ++i)
193 if (!areTypesIsomorphic(DstTy->getContainedType(i),
194 SrcTy->getContainedType(i)))
197 // If everything seems to have lined up, then everything is great.
201 /// linkDefinedTypeBodies - Produce a body for an opaque type in the dest
202 /// module from a type definition in the source module.
203 void TypeMapTy::linkDefinedTypeBodies() {
204 SmallVector<Type*, 16> Elements;
205 SmallString<16> TmpName;
207 // Note that processing entries in this loop (calling 'get') can add new
208 // entries to the SrcDefinitionsToResolve vector.
209 while (!SrcDefinitionsToResolve.empty()) {
210 StructType *SrcSTy = SrcDefinitionsToResolve.pop_back_val();
211 StructType *DstSTy = cast<StructType>(MappedTypes[SrcSTy]);
213 // TypeMap is a many-to-one mapping, if there were multiple types that
214 // provide a body for DstSTy then previous iterations of this loop may have
215 // already handled it. Just ignore this case.
216 if (!DstSTy->isOpaque()) continue;
217 assert(!SrcSTy->isOpaque() && "Not resolving a definition?");
219 // Map the body of the source type over to a new body for the dest type.
220 Elements.resize(SrcSTy->getNumElements());
221 for (unsigned i = 0, e = Elements.size(); i != e; ++i)
222 Elements[i] = getImpl(SrcSTy->getElementType(i));
224 DstSTy->setBody(Elements, SrcSTy->isPacked());
226 // If DstSTy has no name or has a longer name than STy, then viciously steal
228 if (!SrcSTy->hasName()) continue;
229 StringRef SrcName = SrcSTy->getName();
231 if (!DstSTy->hasName() || DstSTy->getName().size() > SrcName.size()) {
232 TmpName.insert(TmpName.end(), SrcName.begin(), SrcName.end());
234 DstSTy->setName(TmpName.str());
239 DstResolvedOpaqueTypes.clear();
242 /// get - Return the mapped type to use for the specified input type from the
244 Type *TypeMapTy::get(Type *Ty) {
245 Type *Result = getImpl(Ty);
247 // If this caused a reference to any struct type, resolve it before returning.
248 if (!SrcDefinitionsToResolve.empty())
249 linkDefinedTypeBodies();
253 /// getImpl - This is the recursive version of get().
254 Type *TypeMapTy::getImpl(Type *Ty) {
255 // If we already have an entry for this type, return it.
256 Type **Entry = &MappedTypes[Ty];
257 if (*Entry) return *Entry;
259 // If this is not a named struct type, then just map all of the elements and
260 // then rebuild the type from inside out.
261 if (!isa<StructType>(Ty) || cast<StructType>(Ty)->isLiteral()) {
262 // If there are no element types to map, then the type is itself. This is
263 // true for the anonymous {} struct, things like 'float', integers, etc.
264 if (Ty->getNumContainedTypes() == 0)
267 // Remap all of the elements, keeping track of whether any of them change.
268 bool AnyChange = false;
269 SmallVector<Type*, 4> ElementTypes;
270 ElementTypes.resize(Ty->getNumContainedTypes());
271 for (unsigned i = 0, e = Ty->getNumContainedTypes(); i != e; ++i) {
272 ElementTypes[i] = getImpl(Ty->getContainedType(i));
273 AnyChange |= ElementTypes[i] != Ty->getContainedType(i);
276 // If we found our type while recursively processing stuff, just use it.
277 Entry = &MappedTypes[Ty];
278 if (*Entry) return *Entry;
280 // If all of the element types mapped directly over, then the type is usable
285 // Otherwise, rebuild a modified type.
286 switch (Ty->getTypeID()) {
287 default: llvm_unreachable("unknown derived type to remap");
288 case Type::ArrayTyID:
289 return *Entry = ArrayType::get(ElementTypes[0],
290 cast<ArrayType>(Ty)->getNumElements());
291 case Type::VectorTyID:
292 return *Entry = VectorType::get(ElementTypes[0],
293 cast<VectorType>(Ty)->getNumElements());
294 case Type::PointerTyID:
295 return *Entry = PointerType::get(ElementTypes[0],
296 cast<PointerType>(Ty)->getAddressSpace());
297 case Type::FunctionTyID:
298 return *Entry = FunctionType::get(ElementTypes[0],
299 makeArrayRef(ElementTypes).slice(1),
300 cast<FunctionType>(Ty)->isVarArg());
301 case Type::StructTyID:
302 // Note that this is only reached for anonymous structs.
303 return *Entry = StructType::get(Ty->getContext(), ElementTypes,
304 cast<StructType>(Ty)->isPacked());
308 // Otherwise, this is an unmapped named struct. If the struct can be directly
309 // mapped over, just use it as-is. This happens in a case when the linked-in
310 // module has something like:
311 // %T = type {%T*, i32}
312 // @GV = global %T* null
313 // where T does not exist at all in the destination module.
315 // The other case we watch for is when the type is not in the destination
316 // module, but that it has to be rebuilt because it refers to something that
317 // is already mapped. For example, if the destination module has:
319 // and the source module has something like
320 // %A' = type { i32 }
321 // %B = type { %A'* }
322 // @GV = global %B* null
323 // then we want to create a new type: "%B = type { %A*}" and have it take the
324 // pristine "%B" name from the source module.
326 // To determine which case this is, we have to recursively walk the type graph
327 // speculating that we'll be able to reuse it unmodified. Only if this is
328 // safe would we map the entire thing over. Because this is an optimization,
329 // and is not required for the prettiness of the linked module, we just skip
330 // it and always rebuild a type here.
331 StructType *STy = cast<StructType>(Ty);
333 // If the type is opaque, we can just use it directly.
334 if (STy->isOpaque()) {
335 // A named structure type from src module is used. Add it to the Set of
336 // identified structs in the destination module.
337 DstStructTypesSet.insert(STy);
341 // Otherwise we create a new type and resolve its body later. This will be
342 // resolved by the top level of get().
343 SrcDefinitionsToResolve.push_back(STy);
344 StructType *DTy = StructType::create(STy->getContext());
345 // A new identified structure type was created. Add it to the set of
346 // identified structs in the destination module.
347 DstStructTypesSet.insert(DTy);
348 DstResolvedOpaqueTypes.insert(DTy);
352 //===----------------------------------------------------------------------===//
353 // ModuleLinker implementation.
354 //===----------------------------------------------------------------------===//
359 /// ValueMaterializerTy - Creates prototypes for functions that are lazily
360 /// linked on the fly. This speeds up linking for modules with many
361 /// lazily linked functions of which few get used.
362 class ValueMaterializerTy : public ValueMaterializer {
365 std::vector<Function*> &LazilyLinkFunctions;
367 ValueMaterializerTy(TypeMapTy &TypeMap, Module *DstM,
368 std::vector<Function*> &LazilyLinkFunctions) :
369 ValueMaterializer(), TypeMap(TypeMap), DstM(DstM),
370 LazilyLinkFunctions(LazilyLinkFunctions) {
373 virtual Value *materializeValueFor(Value *V);
376 /// ModuleLinker - This is an implementation class for the LinkModules
377 /// function, which is the entrypoint for this file.
382 ValueMaterializerTy ValMaterializer;
384 /// ValueMap - Mapping of values from what they used to be in Src, to what
385 /// they are now in DstM. ValueToValueMapTy is a ValueMap, which involves
386 /// some overhead due to the use of Value handles which the Linker doesn't
387 /// actually need, but this allows us to reuse the ValueMapper code.
388 ValueToValueMapTy ValueMap;
390 struct AppendingVarInfo {
391 GlobalVariable *NewGV; // New aggregate global in dest module.
392 Constant *DstInit; // Old initializer from dest module.
393 Constant *SrcInit; // Old initializer from src module.
396 std::vector<AppendingVarInfo> AppendingVars;
398 unsigned Mode; // Mode to treat source module.
400 // Set of items not to link in from source.
401 SmallPtrSet<const Value*, 16> DoNotLinkFromSource;
403 // Vector of functions to lazily link in.
404 std::vector<Function*> LazilyLinkFunctions;
407 std::string ErrorMsg;
409 ModuleLinker(Module *dstM, TypeSet &Set, Module *srcM, unsigned mode)
410 : DstM(dstM), SrcM(srcM), TypeMap(Set),
411 ValMaterializer(TypeMap, DstM, LazilyLinkFunctions),
417 /// emitError - Helper method for setting a message and returning an error
419 bool emitError(const Twine &Message) {
420 ErrorMsg = Message.str();
424 /// getLinkageResult - This analyzes the two global values and determines
425 /// what the result will look like in the destination module.
426 bool getLinkageResult(GlobalValue *Dest, const GlobalValue *Src,
427 GlobalValue::LinkageTypes <,
428 GlobalValue::VisibilityTypes &Vis,
431 /// getLinkedToGlobal - Given a global in the source module, return the
432 /// global in the destination module that is being linked to, if any.
433 GlobalValue *getLinkedToGlobal(GlobalValue *SrcGV) {
434 // If the source has no name it can't link. If it has local linkage,
435 // there is no name match-up going on.
436 if (!SrcGV->hasName() || SrcGV->hasLocalLinkage())
439 // Otherwise see if we have a match in the destination module's symtab.
440 GlobalValue *DGV = DstM->getNamedValue(SrcGV->getName());
441 if (DGV == 0) return 0;
443 // If we found a global with the same name in the dest module, but it has
444 // internal linkage, we are really not doing any linkage here.
445 if (DGV->hasLocalLinkage())
448 // Otherwise, we do in fact link to the destination global.
452 void computeTypeMapping();
454 bool linkAppendingVarProto(GlobalVariable *DstGV, GlobalVariable *SrcGV);
455 bool linkGlobalProto(GlobalVariable *SrcGV);
456 bool linkFunctionProto(Function *SrcF);
457 bool linkAliasProto(GlobalAlias *SrcA);
458 bool linkModuleFlagsMetadata();
460 void linkAppendingVarInit(const AppendingVarInfo &AVI);
461 void linkGlobalInits();
462 void linkFunctionBody(Function *Dst, Function *Src);
463 void linkAliasBodies();
464 void linkNamedMDNodes();
468 /// forceRenaming - The LLVM SymbolTable class autorenames globals that conflict
469 /// in the symbol table. This is good for all clients except for us. Go
470 /// through the trouble to force this back.
471 static void forceRenaming(GlobalValue *GV, StringRef Name) {
472 // If the global doesn't force its name or if it already has the right name,
473 // there is nothing for us to do.
474 if (GV->hasLocalLinkage() || GV->getName() == Name)
477 Module *M = GV->getParent();
479 // If there is a conflict, rename the conflict.
480 if (GlobalValue *ConflictGV = M->getNamedValue(Name)) {
481 GV->takeName(ConflictGV);
482 ConflictGV->setName(Name); // This will cause ConflictGV to get renamed
483 assert(ConflictGV->getName() != Name && "forceRenaming didn't work");
485 GV->setName(Name); // Force the name back
489 /// copyGVAttributes - copy additional attributes (those not needed to construct
490 /// a GlobalValue) from the SrcGV to the DestGV.
491 static void copyGVAttributes(GlobalValue *DestGV, const GlobalValue *SrcGV) {
492 // Use the maximum alignment, rather than just copying the alignment of SrcGV.
493 unsigned Alignment = std::max(DestGV->getAlignment(), SrcGV->getAlignment());
494 DestGV->copyAttributesFrom(SrcGV);
495 DestGV->setAlignment(Alignment);
497 forceRenaming(DestGV, SrcGV->getName());
500 static bool isLessConstraining(GlobalValue::VisibilityTypes a,
501 GlobalValue::VisibilityTypes b) {
502 if (a == GlobalValue::HiddenVisibility)
504 if (b == GlobalValue::HiddenVisibility)
506 if (a == GlobalValue::ProtectedVisibility)
508 if (b == GlobalValue::ProtectedVisibility)
513 Value *ValueMaterializerTy::materializeValueFor(Value *V) {
514 Function *SF = dyn_cast<Function>(V);
518 Function *DF = Function::Create(TypeMap.get(SF->getFunctionType()),
519 SF->getLinkage(), SF->getName(), DstM);
520 copyGVAttributes(DF, SF);
522 LazilyLinkFunctions.push_back(SF);
527 /// getLinkageResult - This analyzes the two global values and determines what
528 /// the result will look like in the destination module. In particular, it
529 /// computes the resultant linkage type and visibility, computes whether the
530 /// global in the source should be copied over to the destination (replacing
531 /// the existing one), and computes whether this linkage is an error or not.
532 bool ModuleLinker::getLinkageResult(GlobalValue *Dest, const GlobalValue *Src,
533 GlobalValue::LinkageTypes <,
534 GlobalValue::VisibilityTypes &Vis,
536 assert(Dest && "Must have two globals being queried");
537 assert(!Src->hasLocalLinkage() &&
538 "If Src has internal linkage, Dest shouldn't be set!");
540 bool SrcIsDeclaration = Src->isDeclaration() && !Src->isMaterializable();
541 bool DestIsDeclaration = Dest->isDeclaration();
543 if (SrcIsDeclaration) {
544 // If Src is external or if both Src & Dest are external.. Just link the
545 // external globals, we aren't adding anything.
546 if (Src->hasDLLImportStorageClass()) {
547 // If one of GVs is marked as DLLImport, result should be dllimport'ed.
548 if (DestIsDeclaration) {
550 LT = Src->getLinkage();
552 } else if (Dest->hasExternalWeakLinkage()) {
553 // If the Dest is weak, use the source linkage.
555 LT = Src->getLinkage();
558 LT = Dest->getLinkage();
560 } else if (DestIsDeclaration && !Dest->hasDLLImportStorageClass()) {
561 // If Dest is external but Src is not:
563 LT = Src->getLinkage();
564 } else if (Src->isWeakForLinker()) {
565 // At this point we know that Dest has LinkOnce, External*, Weak, Common,
567 if (Dest->hasExternalWeakLinkage() ||
568 Dest->hasAvailableExternallyLinkage() ||
569 (Dest->hasLinkOnceLinkage() &&
570 (Src->hasWeakLinkage() || Src->hasCommonLinkage()))) {
572 LT = Src->getLinkage();
575 LT = Dest->getLinkage();
577 } else if (Dest->isWeakForLinker()) {
578 // At this point we know that Src has External* or DLL* linkage.
579 if (Src->hasExternalWeakLinkage()) {
581 LT = Dest->getLinkage();
584 LT = GlobalValue::ExternalLinkage;
587 assert((Dest->hasExternalLinkage() || Dest->hasExternalWeakLinkage()) &&
588 (Src->hasExternalLinkage() || Src->hasExternalWeakLinkage()) &&
589 "Unexpected linkage type!");
590 return emitError("Linking globals named '" + Src->getName() +
591 "': symbol multiply defined!");
594 // Compute the visibility. We follow the rules in the System V Application
596 Vis = isLessConstraining(Src->getVisibility(), Dest->getVisibility()) ?
597 Dest->getVisibility() : Src->getVisibility();
601 /// computeTypeMapping - Loop over all of the linked values to compute type
602 /// mappings. For example, if we link "extern Foo *x" and "Foo *x = NULL", then
603 /// we have two struct types 'Foo' but one got renamed when the module was
604 /// loaded into the same LLVMContext.
605 void ModuleLinker::computeTypeMapping() {
606 // Incorporate globals.
607 for (Module::global_iterator I = SrcM->global_begin(),
608 E = SrcM->global_end(); I != E; ++I) {
609 GlobalValue *DGV = getLinkedToGlobal(I);
610 if (DGV == 0) continue;
612 if (!DGV->hasAppendingLinkage() || !I->hasAppendingLinkage()) {
613 TypeMap.addTypeMapping(DGV->getType(), I->getType());
617 // Unify the element type of appending arrays.
618 ArrayType *DAT = cast<ArrayType>(DGV->getType()->getElementType());
619 ArrayType *SAT = cast<ArrayType>(I->getType()->getElementType());
620 TypeMap.addTypeMapping(DAT->getElementType(), SAT->getElementType());
623 // Incorporate functions.
624 for (Module::iterator I = SrcM->begin(), E = SrcM->end(); I != E; ++I) {
625 if (GlobalValue *DGV = getLinkedToGlobal(I))
626 TypeMap.addTypeMapping(DGV->getType(), I->getType());
629 // Incorporate types by name, scanning all the types in the source module.
630 // At this point, the destination module may have a type "%foo = { i32 }" for
631 // example. When the source module got loaded into the same LLVMContext, if
632 // it had the same type, it would have been renamed to "%foo.42 = { i32 }".
633 TypeFinder SrcStructTypes;
634 SrcStructTypes.run(*SrcM, true);
635 SmallPtrSet<StructType*, 32> SrcStructTypesSet(SrcStructTypes.begin(),
636 SrcStructTypes.end());
638 for (unsigned i = 0, e = SrcStructTypes.size(); i != e; ++i) {
639 StructType *ST = SrcStructTypes[i];
640 if (!ST->hasName()) continue;
642 // Check to see if there is a dot in the name followed by a digit.
643 size_t DotPos = ST->getName().rfind('.');
644 if (DotPos == 0 || DotPos == StringRef::npos ||
645 ST->getName().back() == '.' ||
646 !isdigit(static_cast<unsigned char>(ST->getName()[DotPos+1])))
649 // Check to see if the destination module has a struct with the prefix name.
650 if (StructType *DST = DstM->getTypeByName(ST->getName().substr(0, DotPos)))
651 // Don't use it if this actually came from the source module. They're in
652 // the same LLVMContext after all. Also don't use it unless the type is
653 // actually used in the destination module. This can happen in situations
658 // %Z = type { %A } %B = type { %C.1 }
659 // %A = type { %B.1, [7 x i8] } %C.1 = type { i8* }
660 // %B.1 = type { %C } %A.2 = type { %B.3, [5 x i8] }
661 // %C = type { i8* } %B.3 = type { %C.1 }
663 // When we link Module B with Module A, the '%B' in Module B is
664 // used. However, that would then use '%C.1'. But when we process '%C.1',
665 // we prefer to take the '%C' version. So we are then left with both
666 // '%C.1' and '%C' being used for the same types. This leads to some
667 // variables using one type and some using the other.
668 if (!SrcStructTypesSet.count(DST) && TypeMap.DstStructTypesSet.count(DST))
669 TypeMap.addTypeMapping(DST, ST);
672 // Don't bother incorporating aliases, they aren't generally typed well.
674 // Now that we have discovered all of the type equivalences, get a body for
675 // any 'opaque' types in the dest module that are now resolved.
676 TypeMap.linkDefinedTypeBodies();
679 /// linkAppendingVarProto - If there were any appending global variables, link
680 /// them together now. Return true on error.
681 bool ModuleLinker::linkAppendingVarProto(GlobalVariable *DstGV,
682 GlobalVariable *SrcGV) {
684 if (!SrcGV->hasAppendingLinkage() || !DstGV->hasAppendingLinkage())
685 return emitError("Linking globals named '" + SrcGV->getName() +
686 "': can only link appending global with another appending global!");
688 ArrayType *DstTy = cast<ArrayType>(DstGV->getType()->getElementType());
690 cast<ArrayType>(TypeMap.get(SrcGV->getType()->getElementType()));
691 Type *EltTy = DstTy->getElementType();
693 // Check to see that they two arrays agree on type.
694 if (EltTy != SrcTy->getElementType())
695 return emitError("Appending variables with different element types!");
696 if (DstGV->isConstant() != SrcGV->isConstant())
697 return emitError("Appending variables linked with different const'ness!");
699 if (DstGV->getAlignment() != SrcGV->getAlignment())
701 "Appending variables with different alignment need to be linked!");
703 if (DstGV->getVisibility() != SrcGV->getVisibility())
705 "Appending variables with different visibility need to be linked!");
707 if (DstGV->hasUnnamedAddr() != SrcGV->hasUnnamedAddr())
709 "Appending variables with different unnamed_addr need to be linked!");
711 if (DstGV->getSection() != SrcGV->getSection())
713 "Appending variables with different section name need to be linked!");
715 uint64_t NewSize = DstTy->getNumElements() + SrcTy->getNumElements();
716 ArrayType *NewType = ArrayType::get(EltTy, NewSize);
718 // Create the new global variable.
720 new GlobalVariable(*DstGV->getParent(), NewType, SrcGV->isConstant(),
721 DstGV->getLinkage(), /*init*/0, /*name*/"", DstGV,
722 DstGV->getThreadLocalMode(),
723 DstGV->getType()->getAddressSpace());
725 // Propagate alignment, visibility and section info.
726 copyGVAttributes(NG, DstGV);
728 AppendingVarInfo AVI;
730 AVI.DstInit = DstGV->getInitializer();
731 AVI.SrcInit = SrcGV->getInitializer();
732 AppendingVars.push_back(AVI);
734 // Replace any uses of the two global variables with uses of the new
736 ValueMap[SrcGV] = ConstantExpr::getBitCast(NG, TypeMap.get(SrcGV->getType()));
738 DstGV->replaceAllUsesWith(ConstantExpr::getBitCast(NG, DstGV->getType()));
739 DstGV->eraseFromParent();
741 // Track the source variable so we don't try to link it.
742 DoNotLinkFromSource.insert(SrcGV);
747 /// linkGlobalProto - Loop through the global variables in the src module and
748 /// merge them into the dest module.
749 bool ModuleLinker::linkGlobalProto(GlobalVariable *SGV) {
750 GlobalValue *DGV = getLinkedToGlobal(SGV);
751 llvm::Optional<GlobalValue::VisibilityTypes> NewVisibility;
752 bool HasUnnamedAddr = SGV->hasUnnamedAddr();
755 // Concatenation of appending linkage variables is magic and handled later.
756 if (DGV->hasAppendingLinkage() || SGV->hasAppendingLinkage())
757 return linkAppendingVarProto(cast<GlobalVariable>(DGV), SGV);
759 // Determine whether linkage of these two globals follows the source
760 // module's definition or the destination module's definition.
761 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage;
762 GlobalValue::VisibilityTypes NV;
763 bool LinkFromSrc = false;
764 if (getLinkageResult(DGV, SGV, NewLinkage, NV, LinkFromSrc))
767 HasUnnamedAddr = HasUnnamedAddr && DGV->hasUnnamedAddr();
769 // If we're not linking from the source, then keep the definition that we
772 // Special case for const propagation.
773 if (GlobalVariable *DGVar = dyn_cast<GlobalVariable>(DGV))
774 if (DGVar->isDeclaration() && SGV->isConstant() && !DGVar->isConstant())
775 DGVar->setConstant(true);
777 // Set calculated linkage, visibility and unnamed_addr.
778 DGV->setLinkage(NewLinkage);
779 DGV->setVisibility(*NewVisibility);
780 DGV->setUnnamedAddr(HasUnnamedAddr);
782 // Make sure to remember this mapping.
783 ValueMap[SGV] = ConstantExpr::getBitCast(DGV,TypeMap.get(SGV->getType()));
785 // Track the source global so that we don't attempt to copy it over when
786 // processing global initializers.
787 DoNotLinkFromSource.insert(SGV);
793 // No linking to be performed or linking from the source: simply create an
794 // identical version of the symbol over in the dest module... the
795 // initializer will be filled in later by LinkGlobalInits.
796 GlobalVariable *NewDGV =
797 new GlobalVariable(*DstM, TypeMap.get(SGV->getType()->getElementType()),
798 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
799 SGV->getName(), /*insertbefore*/0,
800 SGV->getThreadLocalMode(),
801 SGV->getType()->getAddressSpace());
802 // Propagate alignment, visibility and section info.
803 copyGVAttributes(NewDGV, SGV);
805 NewDGV->setVisibility(*NewVisibility);
806 NewDGV->setUnnamedAddr(HasUnnamedAddr);
809 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDGV, DGV->getType()));
810 DGV->eraseFromParent();
813 // Make sure to remember this mapping.
814 ValueMap[SGV] = NewDGV;
818 /// linkFunctionProto - Link the function in the source module into the
819 /// destination module if needed, setting up mapping information.
820 bool ModuleLinker::linkFunctionProto(Function *SF) {
821 GlobalValue *DGV = getLinkedToGlobal(SF);
822 llvm::Optional<GlobalValue::VisibilityTypes> NewVisibility;
823 bool HasUnnamedAddr = SF->hasUnnamedAddr();
826 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage;
827 bool LinkFromSrc = false;
828 GlobalValue::VisibilityTypes NV;
829 if (getLinkageResult(DGV, SF, NewLinkage, NV, LinkFromSrc))
832 HasUnnamedAddr = HasUnnamedAddr && DGV->hasUnnamedAddr();
835 // Set calculated linkage
836 DGV->setLinkage(NewLinkage);
837 DGV->setVisibility(*NewVisibility);
838 DGV->setUnnamedAddr(HasUnnamedAddr);
840 // Make sure to remember this mapping.
841 ValueMap[SF] = ConstantExpr::getBitCast(DGV, TypeMap.get(SF->getType()));
843 // Track the function from the source module so we don't attempt to remap
845 DoNotLinkFromSource.insert(SF);
851 // If the function is to be lazily linked, don't create it just yet.
852 // The ValueMaterializerTy will deal with creating it if it's used.
853 if (!DGV && (SF->hasLocalLinkage() || SF->hasLinkOnceLinkage() ||
854 SF->hasAvailableExternallyLinkage())) {
855 DoNotLinkFromSource.insert(SF);
859 // If there is no linkage to be performed or we are linking from the source,
861 Function *NewDF = Function::Create(TypeMap.get(SF->getFunctionType()),
862 SF->getLinkage(), SF->getName(), DstM);
863 copyGVAttributes(NewDF, SF);
865 NewDF->setVisibility(*NewVisibility);
866 NewDF->setUnnamedAddr(HasUnnamedAddr);
869 // Any uses of DF need to change to NewDF, with cast.
870 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDF, DGV->getType()));
871 DGV->eraseFromParent();
874 ValueMap[SF] = NewDF;
878 /// LinkAliasProto - Set up prototypes for any aliases that come over from the
880 bool ModuleLinker::linkAliasProto(GlobalAlias *SGA) {
881 GlobalValue *DGV = getLinkedToGlobal(SGA);
882 llvm::Optional<GlobalValue::VisibilityTypes> NewVisibility;
885 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage;
886 GlobalValue::VisibilityTypes NV;
887 bool LinkFromSrc = false;
888 if (getLinkageResult(DGV, SGA, NewLinkage, NV, LinkFromSrc))
893 // Set calculated linkage.
894 DGV->setLinkage(NewLinkage);
895 DGV->setVisibility(*NewVisibility);
897 // Make sure to remember this mapping.
898 ValueMap[SGA] = ConstantExpr::getBitCast(DGV,TypeMap.get(SGA->getType()));
900 // Track the alias from the source module so we don't attempt to remap it.
901 DoNotLinkFromSource.insert(SGA);
907 // If there is no linkage to be performed or we're linking from the source,
909 GlobalAlias *NewDA = new GlobalAlias(TypeMap.get(SGA->getType()),
910 SGA->getLinkage(), SGA->getName(),
912 copyGVAttributes(NewDA, SGA);
914 NewDA->setVisibility(*NewVisibility);
917 // Any uses of DGV need to change to NewDA, with cast.
918 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDA, DGV->getType()));
919 DGV->eraseFromParent();
922 ValueMap[SGA] = NewDA;
926 static void getArrayElements(Constant *C, SmallVectorImpl<Constant*> &Dest) {
927 unsigned NumElements = cast<ArrayType>(C->getType())->getNumElements();
929 for (unsigned i = 0; i != NumElements; ++i)
930 Dest.push_back(C->getAggregateElement(i));
933 void ModuleLinker::linkAppendingVarInit(const AppendingVarInfo &AVI) {
934 // Merge the initializer.
935 SmallVector<Constant*, 16> Elements;
936 getArrayElements(AVI.DstInit, Elements);
938 Constant *SrcInit = MapValue(AVI.SrcInit, ValueMap, RF_None, &TypeMap, &ValMaterializer);
939 getArrayElements(SrcInit, Elements);
941 ArrayType *NewType = cast<ArrayType>(AVI.NewGV->getType()->getElementType());
942 AVI.NewGV->setInitializer(ConstantArray::get(NewType, Elements));
945 /// linkGlobalInits - Update the initializers in the Dest module now that all
946 /// globals that may be referenced are in Dest.
947 void ModuleLinker::linkGlobalInits() {
948 // Loop over all of the globals in the src module, mapping them over as we go
949 for (Module::const_global_iterator I = SrcM->global_begin(),
950 E = SrcM->global_end(); I != E; ++I) {
952 // Only process initialized GV's or ones not already in dest.
953 if (!I->hasInitializer() || DoNotLinkFromSource.count(I)) continue;
955 // Grab destination global variable.
956 GlobalVariable *DGV = cast<GlobalVariable>(ValueMap[I]);
957 // Figure out what the initializer looks like in the dest module.
958 DGV->setInitializer(MapValue(I->getInitializer(), ValueMap,
959 RF_None, &TypeMap, &ValMaterializer));
963 /// linkFunctionBody - Copy the source function over into the dest function and
964 /// fix up references to values. At this point we know that Dest is an external
965 /// function, and that Src is not.
966 void ModuleLinker::linkFunctionBody(Function *Dst, Function *Src) {
967 assert(Src && Dst && Dst->isDeclaration() && !Src->isDeclaration());
969 // Go through and convert function arguments over, remembering the mapping.
970 Function::arg_iterator DI = Dst->arg_begin();
971 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end();
973 DI->setName(I->getName()); // Copy the name over.
975 // Add a mapping to our mapping.
979 if (Mode == Linker::DestroySource) {
980 // Splice the body of the source function into the dest function.
981 Dst->getBasicBlockList().splice(Dst->end(), Src->getBasicBlockList());
983 // At this point, all of the instructions and values of the function are now
984 // copied over. The only problem is that they are still referencing values in
985 // the Source function as operands. Loop through all of the operands of the
986 // functions and patch them up to point to the local versions.
987 for (Function::iterator BB = Dst->begin(), BE = Dst->end(); BB != BE; ++BB)
988 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
989 RemapInstruction(I, ValueMap, RF_IgnoreMissingEntries,
990 &TypeMap, &ValMaterializer);
993 // Clone the body of the function into the dest function.
994 SmallVector<ReturnInst*, 8> Returns; // Ignore returns.
995 CloneFunctionInto(Dst, Src, ValueMap, false, Returns, "", NULL,
996 &TypeMap, &ValMaterializer);
999 // There is no need to map the arguments anymore.
1000 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end();
1006 /// linkAliasBodies - Insert all of the aliases in Src into the Dest module.
1007 void ModuleLinker::linkAliasBodies() {
1008 for (Module::alias_iterator I = SrcM->alias_begin(), E = SrcM->alias_end();
1010 if (DoNotLinkFromSource.count(I))
1012 if (Constant *Aliasee = I->getAliasee()) {
1013 GlobalAlias *DA = cast<GlobalAlias>(ValueMap[I]);
1014 DA->setAliasee(MapValue(Aliasee, ValueMap, RF_None,
1015 &TypeMap, &ValMaterializer));
1020 /// linkNamedMDNodes - Insert all of the named MDNodes in Src into the Dest
1022 void ModuleLinker::linkNamedMDNodes() {
1023 const NamedMDNode *SrcModFlags = SrcM->getModuleFlagsMetadata();
1024 for (Module::const_named_metadata_iterator I = SrcM->named_metadata_begin(),
1025 E = SrcM->named_metadata_end(); I != E; ++I) {
1026 // Don't link module flags here. Do them separately.
1027 if (&*I == SrcModFlags) continue;
1028 NamedMDNode *DestNMD = DstM->getOrInsertNamedMetadata(I->getName());
1029 // Add Src elements into Dest node.
1030 for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i)
1031 DestNMD->addOperand(MapValue(I->getOperand(i), ValueMap,
1032 RF_None, &TypeMap, &ValMaterializer));
1036 /// linkModuleFlagsMetadata - Merge the linker flags in Src into the Dest
1038 bool ModuleLinker::linkModuleFlagsMetadata() {
1039 // If the source module has no module flags, we are done.
1040 const NamedMDNode *SrcModFlags = SrcM->getModuleFlagsMetadata();
1041 if (!SrcModFlags) return false;
1043 // If the destination module doesn't have module flags yet, then just copy
1044 // over the source module's flags.
1045 NamedMDNode *DstModFlags = DstM->getOrInsertModuleFlagsMetadata();
1046 if (DstModFlags->getNumOperands() == 0) {
1047 for (unsigned I = 0, E = SrcModFlags->getNumOperands(); I != E; ++I)
1048 DstModFlags->addOperand(SrcModFlags->getOperand(I));
1053 // First build a map of the existing module flags and requirements.
1054 DenseMap<MDString*, MDNode*> Flags;
1055 SmallSetVector<MDNode*, 16> Requirements;
1056 for (unsigned I = 0, E = DstModFlags->getNumOperands(); I != E; ++I) {
1057 MDNode *Op = DstModFlags->getOperand(I);
1058 ConstantInt *Behavior = cast<ConstantInt>(Op->getOperand(0));
1059 MDString *ID = cast<MDString>(Op->getOperand(1));
1061 if (Behavior->getZExtValue() == Module::Require) {
1062 Requirements.insert(cast<MDNode>(Op->getOperand(2)));
1068 // Merge in the flags from the source module, and also collect its set of
1070 bool HasErr = false;
1071 for (unsigned I = 0, E = SrcModFlags->getNumOperands(); I != E; ++I) {
1072 MDNode *SrcOp = SrcModFlags->getOperand(I);
1073 ConstantInt *SrcBehavior = cast<ConstantInt>(SrcOp->getOperand(0));
1074 MDString *ID = cast<MDString>(SrcOp->getOperand(1));
1075 MDNode *DstOp = Flags.lookup(ID);
1076 unsigned SrcBehaviorValue = SrcBehavior->getZExtValue();
1078 // If this is a requirement, add it and continue.
1079 if (SrcBehaviorValue == Module::Require) {
1080 // If the destination module does not already have this requirement, add
1082 if (Requirements.insert(cast<MDNode>(SrcOp->getOperand(2)))) {
1083 DstModFlags->addOperand(SrcOp);
1088 // If there is no existing flag with this ID, just add it.
1091 DstModFlags->addOperand(SrcOp);
1095 // Otherwise, perform a merge.
1096 ConstantInt *DstBehavior = cast<ConstantInt>(DstOp->getOperand(0));
1097 unsigned DstBehaviorValue = DstBehavior->getZExtValue();
1099 // If either flag has override behavior, handle it first.
1100 if (DstBehaviorValue == Module::Override) {
1101 // Diagnose inconsistent flags which both have override behavior.
1102 if (SrcBehaviorValue == Module::Override &&
1103 SrcOp->getOperand(2) != DstOp->getOperand(2)) {
1104 HasErr |= emitError("linking module flags '" + ID->getString() +
1105 "': IDs have conflicting override values");
1108 } else if (SrcBehaviorValue == Module::Override) {
1109 // Update the destination flag to that of the source.
1110 DstOp->replaceOperandWith(0, SrcBehavior);
1111 DstOp->replaceOperandWith(2, SrcOp->getOperand(2));
1115 // Diagnose inconsistent merge behavior types.
1116 if (SrcBehaviorValue != DstBehaviorValue) {
1117 HasErr |= emitError("linking module flags '" + ID->getString() +
1118 "': IDs have conflicting behaviors");
1122 // Perform the merge for standard behavior types.
1123 switch (SrcBehaviorValue) {
1124 case Module::Require:
1125 case Module::Override: assert(0 && "not possible"); break;
1126 case Module::Error: {
1127 // Emit an error if the values differ.
1128 if (SrcOp->getOperand(2) != DstOp->getOperand(2)) {
1129 HasErr |= emitError("linking module flags '" + ID->getString() +
1130 "': IDs have conflicting values");
1134 case Module::Warning: {
1135 // Emit a warning if the values differ.
1136 if (SrcOp->getOperand(2) != DstOp->getOperand(2)) {
1137 errs() << "WARNING: linking module flags '" << ID->getString()
1138 << "': IDs have conflicting values";
1142 case Module::Append: {
1143 MDNode *DstValue = cast<MDNode>(DstOp->getOperand(2));
1144 MDNode *SrcValue = cast<MDNode>(SrcOp->getOperand(2));
1145 unsigned NumOps = DstValue->getNumOperands() + SrcValue->getNumOperands();
1146 Value **VP, **Values = VP = new Value*[NumOps];
1147 for (unsigned i = 0, e = DstValue->getNumOperands(); i != e; ++i, ++VP)
1148 *VP = DstValue->getOperand(i);
1149 for (unsigned i = 0, e = SrcValue->getNumOperands(); i != e; ++i, ++VP)
1150 *VP = SrcValue->getOperand(i);
1151 DstOp->replaceOperandWith(2, MDNode::get(DstM->getContext(),
1152 ArrayRef<Value*>(Values,
1157 case Module::AppendUnique: {
1158 SmallSetVector<Value*, 16> Elts;
1159 MDNode *DstValue = cast<MDNode>(DstOp->getOperand(2));
1160 MDNode *SrcValue = cast<MDNode>(SrcOp->getOperand(2));
1161 for (unsigned i = 0, e = DstValue->getNumOperands(); i != e; ++i)
1162 Elts.insert(DstValue->getOperand(i));
1163 for (unsigned i = 0, e = SrcValue->getNumOperands(); i != e; ++i)
1164 Elts.insert(SrcValue->getOperand(i));
1165 DstOp->replaceOperandWith(2, MDNode::get(DstM->getContext(),
1166 ArrayRef<Value*>(Elts.begin(),
1173 // Check all of the requirements.
1174 for (unsigned I = 0, E = Requirements.size(); I != E; ++I) {
1175 MDNode *Requirement = Requirements[I];
1176 MDString *Flag = cast<MDString>(Requirement->getOperand(0));
1177 Value *ReqValue = Requirement->getOperand(1);
1179 MDNode *Op = Flags[Flag];
1180 if (!Op || Op->getOperand(2) != ReqValue) {
1181 HasErr |= emitError("linking module flags '" + Flag->getString() +
1182 "': does not have the required value");
1190 bool ModuleLinker::run() {
1191 assert(DstM && "Null destination module");
1192 assert(SrcM && "Null source module");
1194 // Inherit the target data from the source module if the destination module
1195 // doesn't have one already.
1196 if (DstM->getDataLayout().empty() && !SrcM->getDataLayout().empty())
1197 DstM->setDataLayout(SrcM->getDataLayout());
1199 // Copy the target triple from the source to dest if the dest's is empty.
1200 if (DstM->getTargetTriple().empty() && !SrcM->getTargetTriple().empty())
1201 DstM->setTargetTriple(SrcM->getTargetTriple());
1203 if (!SrcM->getDataLayout().empty() && !DstM->getDataLayout().empty() &&
1204 SrcM->getDataLayout() != DstM->getDataLayout())
1205 errs() << "WARNING: Linking two modules of different data layouts!\n";
1206 if (!SrcM->getTargetTriple().empty() &&
1207 DstM->getTargetTriple() != SrcM->getTargetTriple()) {
1208 errs() << "WARNING: Linking two modules of different target triples: ";
1209 if (!SrcM->getModuleIdentifier().empty())
1210 errs() << SrcM->getModuleIdentifier() << ": ";
1211 errs() << "'" << SrcM->getTargetTriple() << "' and '"
1212 << DstM->getTargetTriple() << "'\n";
1215 // Append the module inline asm string.
1216 if (!SrcM->getModuleInlineAsm().empty()) {
1217 if (DstM->getModuleInlineAsm().empty())
1218 DstM->setModuleInlineAsm(SrcM->getModuleInlineAsm());
1220 DstM->setModuleInlineAsm(DstM->getModuleInlineAsm()+"\n"+
1221 SrcM->getModuleInlineAsm());
1224 // Loop over all of the linked values to compute type mappings.
1225 computeTypeMapping();
1227 // Insert all of the globals in src into the DstM module... without linking
1228 // initializers (which could refer to functions not yet mapped over).
1229 for (Module::global_iterator I = SrcM->global_begin(),
1230 E = SrcM->global_end(); I != E; ++I)
1231 if (linkGlobalProto(I))
1234 // Link the functions together between the two modules, without doing function
1235 // bodies... this just adds external function prototypes to the DstM
1236 // function... We do this so that when we begin processing function bodies,
1237 // all of the global values that may be referenced are available in our
1239 for (Module::iterator I = SrcM->begin(), E = SrcM->end(); I != E; ++I)
1240 if (linkFunctionProto(I))
1243 // If there were any aliases, link them now.
1244 for (Module::alias_iterator I = SrcM->alias_begin(),
1245 E = SrcM->alias_end(); I != E; ++I)
1246 if (linkAliasProto(I))
1249 for (unsigned i = 0, e = AppendingVars.size(); i != e; ++i)
1250 linkAppendingVarInit(AppendingVars[i]);
1252 // Link in the function bodies that are defined in the source module into
1254 for (Module::iterator SF = SrcM->begin(), E = SrcM->end(); SF != E; ++SF) {
1255 // Skip if not linking from source.
1256 if (DoNotLinkFromSource.count(SF)) continue;
1258 Function *DF = cast<Function>(ValueMap[SF]);
1259 if (SF->hasPrefixData()) {
1260 // Link in the prefix data.
1261 DF->setPrefixData(MapValue(
1262 SF->getPrefixData(), ValueMap, RF_None, &TypeMap, &ValMaterializer));
1265 // Skip if no body (function is external) or materialize.
1266 if (SF->isDeclaration()) {
1267 if (!SF->isMaterializable())
1269 if (SF->Materialize(&ErrorMsg))
1273 linkFunctionBody(DF, SF);
1274 SF->Dematerialize();
1277 // Resolve all uses of aliases with aliasees.
1280 // Remap all of the named MDNodes in Src into the DstM module. We do this
1281 // after linking GlobalValues so that MDNodes that reference GlobalValues
1282 // are properly remapped.
1285 // Merge the module flags into the DstM module.
1286 if (linkModuleFlagsMetadata())
1289 // Update the initializers in the DstM module now that all globals that may
1290 // be referenced are in DstM.
1293 // Process vector of lazily linked in functions.
1294 bool LinkedInAnyFunctions;
1296 LinkedInAnyFunctions = false;
1298 for(std::vector<Function*>::iterator I = LazilyLinkFunctions.begin(),
1299 E = LazilyLinkFunctions.end(); I != E; ++I) {
1304 Function *DF = cast<Function>(ValueMap[SF]);
1305 if (SF->hasPrefixData()) {
1306 // Link in the prefix data.
1307 DF->setPrefixData(MapValue(SF->getPrefixData(),
1314 // Materialize if necessary.
1315 if (SF->isDeclaration()) {
1316 if (!SF->isMaterializable())
1318 if (SF->Materialize(&ErrorMsg))
1322 // Erase from vector *before* the function body is linked - linkFunctionBody could
1324 LazilyLinkFunctions.erase(I);
1326 // Link in function body.
1327 linkFunctionBody(DF, SF);
1328 SF->Dematerialize();
1330 // Set flag to indicate we may have more functions to lazily link in
1331 // since we linked in a function.
1332 LinkedInAnyFunctions = true;
1335 } while (LinkedInAnyFunctions);
1337 // Now that all of the types from the source are used, resolve any structs
1338 // copied over to the dest that didn't exist there.
1339 TypeMap.linkDefinedTypeBodies();
1344 Linker::Linker(Module *M) : Composite(M) {
1345 TypeFinder StructTypes;
1346 StructTypes.run(*M, true);
1347 IdentifiedStructTypes.insert(StructTypes.begin(), StructTypes.end());
1353 void Linker::deleteModule() {
1358 bool Linker::linkInModule(Module *Src, unsigned Mode, std::string *ErrorMsg) {
1359 ModuleLinker TheLinker(Composite, IdentifiedStructTypes, Src, Mode);
1360 if (TheLinker.run()) {
1362 *ErrorMsg = TheLinker.ErrorMsg;
1368 //===----------------------------------------------------------------------===//
1369 // LinkModules entrypoint.
1370 //===----------------------------------------------------------------------===//
1372 /// LinkModules - This function links two modules together, with the resulting
1373 /// Dest module modified to be the composite of the two input modules. If an
1374 /// error occurs, true is returned and ErrorMsg (if not null) is set to indicate
1375 /// the problem. Upon failure, the Dest module could be in a modified state,
1376 /// and shouldn't be relied on to be consistent.
1377 bool Linker::LinkModules(Module *Dest, Module *Src, unsigned Mode,
1378 std::string *ErrorMsg) {
1380 return L.linkInModule(Src, Mode, ErrorMsg);
1383 //===----------------------------------------------------------------------===//
1385 //===----------------------------------------------------------------------===//
1387 LLVMBool LLVMLinkModules(LLVMModuleRef Dest, LLVMModuleRef Src,
1388 LLVMLinkerMode Mode, char **OutMessages) {
1389 std::string Messages;
1390 LLVMBool Result = Linker::LinkModules(unwrap(Dest), unwrap(Src),
1391 Mode, OutMessages? &Messages : 0);
1393 *OutMessages = strdup(Messages.c_str());