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/Linker.h"
15 #include "llvm-c/Linker.h"
16 #include "llvm/ADT/Hashing.h"
17 #include "llvm/ADT/Optional.h"
18 #include "llvm/ADT/SetVector.h"
19 #include "llvm/ADT/SmallString.h"
20 #include "llvm/ADT/Statistic.h"
21 #include "llvm/IR/Constants.h"
22 #include "llvm/IR/DiagnosticInfo.h"
23 #include "llvm/IR/DiagnosticPrinter.h"
24 #include "llvm/IR/LLVMContext.h"
25 #include "llvm/IR/Module.h"
26 #include "llvm/IR/TypeFinder.h"
27 #include "llvm/Support/CommandLine.h"
28 #include "llvm/Support/Debug.h"
29 #include "llvm/Support/raw_ostream.h"
30 #include "llvm/Transforms/Utils/Cloning.h"
36 //===----------------------------------------------------------------------===//
37 // TypeMap implementation.
38 //===----------------------------------------------------------------------===//
41 class TypeMapTy : public ValueMapTypeRemapper {
42 /// This is a mapping from a source type to a destination type to use.
43 DenseMap<Type*, Type*> MappedTypes;
45 /// When checking to see if two subgraphs are isomorphic, we speculatively
46 /// add types to MappedTypes, but keep track of them here in case we need to
48 SmallVector<Type*, 16> SpeculativeTypes;
50 SmallVector<StructType*, 16> SpeculativeDstOpaqueTypes;
52 /// This is a list of non-opaque structs in the source module that are mapped
53 /// to an opaque struct in the destination module.
54 SmallVector<StructType*, 16> SrcDefinitionsToResolve;
56 /// This is the set of opaque types in the destination modules who are
57 /// getting a body from the source module.
58 SmallPtrSet<StructType*, 16> DstResolvedOpaqueTypes;
61 TypeMapTy(Linker::IdentifiedStructTypeSet &DstStructTypesSet)
62 : DstStructTypesSet(DstStructTypesSet) {}
64 Linker::IdentifiedStructTypeSet &DstStructTypesSet;
65 /// Indicate that the specified type in the destination module is conceptually
66 /// equivalent to the specified type in the source module.
67 void addTypeMapping(Type *DstTy, Type *SrcTy);
69 /// Produce a body for an opaque type in the dest module from a type
70 /// definition in the source module.
71 void linkDefinedTypeBodies();
73 /// Return the mapped type to use for the specified input type from the
75 Type *get(Type *SrcTy);
76 Type *get(Type *SrcTy, SmallPtrSet<StructType *, 8> &Visited);
78 void finishType(StructType *DTy, StructType *STy, ArrayRef<Type *> ETypes);
80 FunctionType *get(FunctionType *T) {
81 return cast<FunctionType>(get((Type *)T));
84 /// Dump out the type map for debugging purposes.
86 for (auto &Pair : MappedTypes) {
87 dbgs() << "TypeMap: ";
88 Pair.first->print(dbgs());
90 Pair.second->print(dbgs());
96 Type *remapType(Type *SrcTy) override { return get(SrcTy); }
98 bool areTypesIsomorphic(Type *DstTy, Type *SrcTy);
102 void TypeMapTy::addTypeMapping(Type *DstTy, Type *SrcTy) {
103 assert(SpeculativeTypes.empty());
104 assert(SpeculativeDstOpaqueTypes.empty());
106 // Check to see if these types are recursively isomorphic and establish a
107 // mapping between them if so.
108 if (!areTypesIsomorphic(DstTy, SrcTy)) {
109 // Oops, they aren't isomorphic. Just discard this request by rolling out
110 // any speculative mappings we've established.
111 for (Type *Ty : SpeculativeTypes)
112 MappedTypes.erase(Ty);
114 SrcDefinitionsToResolve.resize(SrcDefinitionsToResolve.size() -
115 SpeculativeDstOpaqueTypes.size());
116 for (StructType *Ty : SpeculativeDstOpaqueTypes)
117 DstResolvedOpaqueTypes.erase(Ty);
119 for (Type *Ty : SpeculativeTypes)
120 if (auto *STy = dyn_cast<StructType>(Ty))
124 SpeculativeTypes.clear();
125 SpeculativeDstOpaqueTypes.clear();
128 /// Recursively walk this pair of types, returning true if they are isomorphic,
129 /// false if they are not.
130 bool TypeMapTy::areTypesIsomorphic(Type *DstTy, Type *SrcTy) {
131 // Two types with differing kinds are clearly not isomorphic.
132 if (DstTy->getTypeID() != SrcTy->getTypeID())
135 // If we have an entry in the MappedTypes table, then we have our answer.
136 Type *&Entry = MappedTypes[SrcTy];
138 return Entry == DstTy;
140 // Two identical types are clearly isomorphic. Remember this
141 // non-speculatively.
142 if (DstTy == SrcTy) {
147 // Okay, we have two types with identical kinds that we haven't seen before.
149 // If this is an opaque struct type, special case it.
150 if (StructType *SSTy = dyn_cast<StructType>(SrcTy)) {
151 // Mapping an opaque type to any struct, just keep the dest struct.
152 if (SSTy->isOpaque()) {
154 SpeculativeTypes.push_back(SrcTy);
158 // Mapping a non-opaque source type to an opaque dest. If this is the first
159 // type that we're mapping onto this destination type then we succeed. Keep
160 // the dest, but fill it in later. If this is the second (different) type
161 // that we're trying to map onto the same opaque type then we fail.
162 if (cast<StructType>(DstTy)->isOpaque()) {
163 // We can only map one source type onto the opaque destination type.
164 if (!DstResolvedOpaqueTypes.insert(cast<StructType>(DstTy)).second)
166 SrcDefinitionsToResolve.push_back(SSTy);
167 SpeculativeTypes.push_back(SrcTy);
168 SpeculativeDstOpaqueTypes.push_back(cast<StructType>(DstTy));
174 // If the number of subtypes disagree between the two types, then we fail.
175 if (SrcTy->getNumContainedTypes() != DstTy->getNumContainedTypes())
178 // Fail if any of the extra properties (e.g. array size) of the type disagree.
179 if (isa<IntegerType>(DstTy))
180 return false; // bitwidth disagrees.
181 if (PointerType *PT = dyn_cast<PointerType>(DstTy)) {
182 if (PT->getAddressSpace() != cast<PointerType>(SrcTy)->getAddressSpace())
185 } else if (FunctionType *FT = dyn_cast<FunctionType>(DstTy)) {
186 if (FT->isVarArg() != cast<FunctionType>(SrcTy)->isVarArg())
188 } else if (StructType *DSTy = dyn_cast<StructType>(DstTy)) {
189 StructType *SSTy = cast<StructType>(SrcTy);
190 if (DSTy->isLiteral() != SSTy->isLiteral() ||
191 DSTy->isPacked() != SSTy->isPacked())
193 } else if (ArrayType *DATy = dyn_cast<ArrayType>(DstTy)) {
194 if (DATy->getNumElements() != cast<ArrayType>(SrcTy)->getNumElements())
196 } else if (VectorType *DVTy = dyn_cast<VectorType>(DstTy)) {
197 if (DVTy->getNumElements() != cast<VectorType>(SrcTy)->getNumElements())
201 // Otherwise, we speculate that these two types will line up and recursively
202 // check the subelements.
204 SpeculativeTypes.push_back(SrcTy);
206 for (unsigned I = 0, E = SrcTy->getNumContainedTypes(); I != E; ++I)
207 if (!areTypesIsomorphic(DstTy->getContainedType(I),
208 SrcTy->getContainedType(I)))
211 // If everything seems to have lined up, then everything is great.
215 void TypeMapTy::linkDefinedTypeBodies() {
216 SmallVector<Type*, 16> Elements;
217 for (StructType *SrcSTy : SrcDefinitionsToResolve) {
218 StructType *DstSTy = cast<StructType>(MappedTypes[SrcSTy]);
219 assert(DstSTy->isOpaque());
221 // Map the body of the source type over to a new body for the dest type.
222 Elements.resize(SrcSTy->getNumElements());
223 for (unsigned I = 0, E = Elements.size(); I != E; ++I)
224 Elements[I] = get(SrcSTy->getElementType(I));
226 DstSTy->setBody(Elements, SrcSTy->isPacked());
228 SrcDefinitionsToResolve.clear();
229 DstResolvedOpaqueTypes.clear();
232 void TypeMapTy::finishType(StructType *DTy, StructType *STy,
233 ArrayRef<Type *> ETypes) {
234 DTy->setBody(ETypes, STy->isPacked());
237 if (STy->hasName()) {
238 SmallString<16> TmpName = STy->getName();
240 DTy->setName(TmpName);
243 DstStructTypesSet.addNonOpaque(DTy);
246 Type *TypeMapTy::get(Type *Ty) {
247 SmallPtrSet<StructType *, 8> Visited;
248 return get(Ty, Visited);
251 Type *TypeMapTy::get(Type *Ty, SmallPtrSet<StructType *, 8> &Visited) {
252 // If we already have an entry for this type, return it.
253 Type **Entry = &MappedTypes[Ty];
257 // These are types that LLVM itself will unique.
258 bool IsUniqued = !isa<StructType>(Ty) || cast<StructType>(Ty)->isLiteral();
262 for (auto &Pair : MappedTypes) {
263 assert(!(Pair.first != Ty && Pair.second == Ty) &&
264 "mapping to a source type");
269 if (!IsUniqued && !Visited.insert(cast<StructType>(Ty)).second) {
270 StructType *DTy = StructType::create(Ty->getContext());
274 // If this is not a recursive type, then just map all of the elements and
275 // then rebuild the type from inside out.
276 SmallVector<Type *, 4> ElementTypes;
278 // If there are no element types to map, then the type is itself. This is
279 // true for the anonymous {} struct, things like 'float', integers, etc.
280 if (Ty->getNumContainedTypes() == 0 && IsUniqued)
283 // Remap all of the elements, keeping track of whether any of them change.
284 bool AnyChange = false;
285 ElementTypes.resize(Ty->getNumContainedTypes());
286 for (unsigned I = 0, E = Ty->getNumContainedTypes(); I != E; ++I) {
287 ElementTypes[I] = get(Ty->getContainedType(I), Visited);
288 AnyChange |= ElementTypes[I] != Ty->getContainedType(I);
291 // If we found our type while recursively processing stuff, just use it.
292 Entry = &MappedTypes[Ty];
294 if (auto *DTy = dyn_cast<StructType>(*Entry)) {
295 if (DTy->isOpaque()) {
296 auto *STy = cast<StructType>(Ty);
297 finishType(DTy, STy, ElementTypes);
303 // If all of the element types mapped directly over and the type is not
304 // a nomed struct, then the type is usable as-is.
305 if (!AnyChange && IsUniqued)
308 // Otherwise, rebuild a modified type.
309 switch (Ty->getTypeID()) {
311 llvm_unreachable("unknown derived type to remap");
312 case Type::ArrayTyID:
313 return *Entry = ArrayType::get(ElementTypes[0],
314 cast<ArrayType>(Ty)->getNumElements());
315 case Type::VectorTyID:
316 return *Entry = VectorType::get(ElementTypes[0],
317 cast<VectorType>(Ty)->getNumElements());
318 case Type::PointerTyID:
319 return *Entry = PointerType::get(ElementTypes[0],
320 cast<PointerType>(Ty)->getAddressSpace());
321 case Type::FunctionTyID:
322 return *Entry = FunctionType::get(ElementTypes[0],
323 makeArrayRef(ElementTypes).slice(1),
324 cast<FunctionType>(Ty)->isVarArg());
325 case Type::StructTyID: {
326 auto *STy = cast<StructType>(Ty);
327 bool IsPacked = STy->isPacked();
329 return *Entry = StructType::get(Ty->getContext(), ElementTypes, IsPacked);
331 // If the type is opaque, we can just use it directly.
332 if (STy->isOpaque()) {
333 DstStructTypesSet.addOpaque(STy);
337 if (StructType *OldT =
338 DstStructTypesSet.findNonOpaque(ElementTypes, IsPacked)) {
340 return *Entry = OldT;
344 DstStructTypesSet.addNonOpaque(STy);
348 StructType *DTy = StructType::create(Ty->getContext());
349 finishType(DTy, STy, ElementTypes);
355 //===----------------------------------------------------------------------===//
356 // ModuleLinker implementation.
357 //===----------------------------------------------------------------------===//
362 /// Creates prototypes for functions that are lazily linked on the fly. This
363 /// speeds up linking for modules with many/ lazily linked functions of which
365 class ValueMaterializerTy : public ValueMaterializer {
368 std::vector<Function *> &LazilyLinkFunctions;
371 ValueMaterializerTy(TypeMapTy &TypeMap, Module *DstM,
372 std::vector<Function *> &LazilyLinkFunctions)
373 : ValueMaterializer(), TypeMap(TypeMap), DstM(DstM),
374 LazilyLinkFunctions(LazilyLinkFunctions) {}
376 Value *materializeValueFor(Value *V) override;
379 class LinkDiagnosticInfo : public DiagnosticInfo {
383 LinkDiagnosticInfo(DiagnosticSeverity Severity, const Twine &Msg);
384 void print(DiagnosticPrinter &DP) const override;
386 LinkDiagnosticInfo::LinkDiagnosticInfo(DiagnosticSeverity Severity,
388 : DiagnosticInfo(DK_Linker, Severity), Msg(Msg) {}
389 void LinkDiagnosticInfo::print(DiagnosticPrinter &DP) const { DP << Msg; }
391 /// This is an implementation class for the LinkModules function, which is the
392 /// entrypoint for this file.
397 ValueMaterializerTy ValMaterializer;
399 /// Mapping of values from what they used to be in Src, to what they are now
400 /// in DstM. ValueToValueMapTy is a ValueMap, which involves some overhead
401 /// due to the use of Value handles which the Linker doesn't actually need,
402 /// but this allows us to reuse the ValueMapper code.
403 ValueToValueMapTy ValueMap;
405 struct AppendingVarInfo {
406 GlobalVariable *NewGV; // New aggregate global in dest module.
407 const Constant *DstInit; // Old initializer from dest module.
408 const Constant *SrcInit; // Old initializer from src module.
411 std::vector<AppendingVarInfo> AppendingVars;
413 // Set of items not to link in from source.
414 SmallPtrSet<const Value *, 16> DoNotLinkFromSource;
416 // Vector of functions to lazily link in.
417 std::vector<Function *> LazilyLinkFunctions;
419 Linker::DiagnosticHandlerFunction DiagnosticHandler;
422 ModuleLinker(Module *dstM, Linker::IdentifiedStructTypeSet &Set, Module *srcM,
423 Linker::DiagnosticHandlerFunction DiagnosticHandler)
424 : DstM(dstM), SrcM(srcM), TypeMap(Set),
425 ValMaterializer(TypeMap, DstM, LazilyLinkFunctions),
426 DiagnosticHandler(DiagnosticHandler) {}
431 bool shouldLinkFromSource(bool &LinkFromSrc, const GlobalValue &Dest,
432 const GlobalValue &Src);
434 /// Helper method for setting a message and returning an error code.
435 bool emitError(const Twine &Message) {
436 DiagnosticHandler(LinkDiagnosticInfo(DS_Error, Message));
440 void emitWarning(const Twine &Message) {
441 DiagnosticHandler(LinkDiagnosticInfo(DS_Warning, Message));
444 bool getComdatLeader(Module *M, StringRef ComdatName,
445 const GlobalVariable *&GVar);
446 bool computeResultingSelectionKind(StringRef ComdatName,
447 Comdat::SelectionKind Src,
448 Comdat::SelectionKind Dst,
449 Comdat::SelectionKind &Result,
451 std::map<const Comdat *, std::pair<Comdat::SelectionKind, bool>>
453 bool getComdatResult(const Comdat *SrcC, Comdat::SelectionKind &SK,
456 /// Given a global in the source module, return the global in the
457 /// destination module that is being linked to, if any.
458 GlobalValue *getLinkedToGlobal(const GlobalValue *SrcGV) {
459 // If the source has no name it can't link. If it has local linkage,
460 // there is no name match-up going on.
461 if (!SrcGV->hasName() || SrcGV->hasLocalLinkage())
464 // Otherwise see if we have a match in the destination module's symtab.
465 GlobalValue *DGV = DstM->getNamedValue(SrcGV->getName());
469 // If we found a global with the same name in the dest module, but it has
470 // internal linkage, we are really not doing any linkage here.
471 if (DGV->hasLocalLinkage())
474 // Otherwise, we do in fact link to the destination global.
478 void computeTypeMapping();
480 void upgradeMismatchedGlobalArray(StringRef Name);
481 void upgradeMismatchedGlobals();
483 bool linkAppendingVarProto(GlobalVariable *DstGV,
484 const GlobalVariable *SrcGV);
486 bool linkGlobalValueProto(GlobalValue *GV);
487 GlobalValue *linkGlobalVariableProto(const GlobalVariable *SGVar);
488 GlobalValue *linkFunctionProto(const Function *SF, GlobalValue *DGV);
489 GlobalValue *linkGlobalAliasProto(const GlobalAlias *SGA);
491 bool linkModuleFlagsMetadata();
493 void linkAppendingVarInit(const AppendingVarInfo &AVI);
494 void linkGlobalInits();
495 void linkFunctionBody(Function *Dst, Function *Src);
496 void linkAliasBodies();
497 void linkNamedMDNodes();
501 /// The LLVM SymbolTable class autorenames globals that conflict in the symbol
502 /// table. This is good for all clients except for us. Go through the trouble
503 /// to force this back.
504 static void forceRenaming(GlobalValue *GV, StringRef Name) {
505 // If the global doesn't force its name or if it already has the right name,
506 // there is nothing for us to do.
507 if (GV->hasLocalLinkage() || GV->getName() == Name)
510 Module *M = GV->getParent();
512 // If there is a conflict, rename the conflict.
513 if (GlobalValue *ConflictGV = M->getNamedValue(Name)) {
514 GV->takeName(ConflictGV);
515 ConflictGV->setName(Name); // This will cause ConflictGV to get renamed
516 assert(ConflictGV->getName() != Name && "forceRenaming didn't work");
518 GV->setName(Name); // Force the name back
522 /// copy additional attributes (those not needed to construct a GlobalValue)
523 /// from the SrcGV to the DestGV.
524 static void copyGVAttributes(GlobalValue *DestGV, const GlobalValue *SrcGV) {
525 DestGV->copyAttributesFrom(SrcGV);
526 forceRenaming(DestGV, SrcGV->getName());
529 static bool isLessConstraining(GlobalValue::VisibilityTypes a,
530 GlobalValue::VisibilityTypes b) {
531 if (a == GlobalValue::HiddenVisibility)
533 if (b == GlobalValue::HiddenVisibility)
535 if (a == GlobalValue::ProtectedVisibility)
537 if (b == GlobalValue::ProtectedVisibility)
542 Value *ValueMaterializerTy::materializeValueFor(Value *V) {
543 Function *SF = dyn_cast<Function>(V);
547 Function *DF = Function::Create(TypeMap.get(SF->getFunctionType()),
548 SF->getLinkage(), SF->getName(), DstM);
549 copyGVAttributes(DF, SF);
551 if (Comdat *SC = SF->getComdat()) {
552 Comdat *DC = DstM->getOrInsertComdat(SC->getName());
556 LazilyLinkFunctions.push_back(SF);
560 bool ModuleLinker::getComdatLeader(Module *M, StringRef ComdatName,
561 const GlobalVariable *&GVar) {
562 const GlobalValue *GVal = M->getNamedValue(ComdatName);
563 if (const auto *GA = dyn_cast_or_null<GlobalAlias>(GVal)) {
564 GVal = GA->getBaseObject();
566 // We cannot resolve the size of the aliasee yet.
567 return emitError("Linking COMDATs named '" + ComdatName +
568 "': COMDAT key involves incomputable alias size.");
571 GVar = dyn_cast_or_null<GlobalVariable>(GVal);
574 "Linking COMDATs named '" + ComdatName +
575 "': GlobalVariable required for data dependent selection!");
580 bool ModuleLinker::computeResultingSelectionKind(StringRef ComdatName,
581 Comdat::SelectionKind Src,
582 Comdat::SelectionKind Dst,
583 Comdat::SelectionKind &Result,
585 // The ability to mix Comdat::SelectionKind::Any with
586 // Comdat::SelectionKind::Largest is a behavior that comes from COFF.
587 bool DstAnyOrLargest = Dst == Comdat::SelectionKind::Any ||
588 Dst == Comdat::SelectionKind::Largest;
589 bool SrcAnyOrLargest = Src == Comdat::SelectionKind::Any ||
590 Src == Comdat::SelectionKind::Largest;
591 if (DstAnyOrLargest && SrcAnyOrLargest) {
592 if (Dst == Comdat::SelectionKind::Largest ||
593 Src == Comdat::SelectionKind::Largest)
594 Result = Comdat::SelectionKind::Largest;
596 Result = Comdat::SelectionKind::Any;
597 } else if (Src == Dst) {
600 return emitError("Linking COMDATs named '" + ComdatName +
601 "': invalid selection kinds!");
605 case Comdat::SelectionKind::Any:
609 case Comdat::SelectionKind::NoDuplicates:
610 return emitError("Linking COMDATs named '" + ComdatName +
611 "': noduplicates has been violated!");
612 case Comdat::SelectionKind::ExactMatch:
613 case Comdat::SelectionKind::Largest:
614 case Comdat::SelectionKind::SameSize: {
615 const GlobalVariable *DstGV;
616 const GlobalVariable *SrcGV;
617 if (getComdatLeader(DstM, ComdatName, DstGV) ||
618 getComdatLeader(SrcM, ComdatName, SrcGV))
621 const DataLayout *DstDL = DstM->getDataLayout();
622 const DataLayout *SrcDL = SrcM->getDataLayout();
623 if (!DstDL || !SrcDL) {
625 "Linking COMDATs named '" + ComdatName +
626 "': can't do size dependent selection without DataLayout!");
629 DstDL->getTypeAllocSize(DstGV->getType()->getPointerElementType());
631 SrcDL->getTypeAllocSize(SrcGV->getType()->getPointerElementType());
632 if (Result == Comdat::SelectionKind::ExactMatch) {
633 if (SrcGV->getInitializer() != DstGV->getInitializer())
634 return emitError("Linking COMDATs named '" + ComdatName +
635 "': ExactMatch violated!");
637 } else if (Result == Comdat::SelectionKind::Largest) {
638 LinkFromSrc = SrcSize > DstSize;
639 } else if (Result == Comdat::SelectionKind::SameSize) {
640 if (SrcSize != DstSize)
641 return emitError("Linking COMDATs named '" + ComdatName +
642 "': SameSize violated!");
645 llvm_unreachable("unknown selection kind");
654 bool ModuleLinker::getComdatResult(const Comdat *SrcC,
655 Comdat::SelectionKind &Result,
657 Comdat::SelectionKind SSK = SrcC->getSelectionKind();
658 StringRef ComdatName = SrcC->getName();
659 Module::ComdatSymTabType &ComdatSymTab = DstM->getComdatSymbolTable();
660 Module::ComdatSymTabType::iterator DstCI = ComdatSymTab.find(ComdatName);
662 if (DstCI == ComdatSymTab.end()) {
663 // Use the comdat if it is only available in one of the modules.
669 const Comdat *DstC = &DstCI->second;
670 Comdat::SelectionKind DSK = DstC->getSelectionKind();
671 return computeResultingSelectionKind(ComdatName, SSK, DSK, Result,
675 bool ModuleLinker::shouldLinkFromSource(bool &LinkFromSrc,
676 const GlobalValue &Dest,
677 const GlobalValue &Src) {
678 // We always have to add Src if it has appending linkage.
679 if (Src.hasAppendingLinkage()) {
684 bool SrcIsDeclaration = Src.isDeclarationForLinker();
685 bool DestIsDeclaration = Dest.isDeclarationForLinker();
687 if (SrcIsDeclaration) {
688 // If Src is external or if both Src & Dest are external.. Just link the
689 // external globals, we aren't adding anything.
690 if (Src.hasDLLImportStorageClass()) {
691 // If one of GVs is marked as DLLImport, result should be dllimport'ed.
692 LinkFromSrc = DestIsDeclaration;
695 // If the Dest is weak, use the source linkage.
696 LinkFromSrc = Dest.hasExternalWeakLinkage();
700 if (DestIsDeclaration) {
701 // If Dest is external but Src is not:
706 if (Src.hasCommonLinkage()) {
707 if (Dest.hasLinkOnceLinkage() || Dest.hasWeakLinkage()) {
712 if (!Dest.hasCommonLinkage()) {
717 // FIXME: Make datalayout mandatory and just use getDataLayout().
718 DataLayout DL(Dest.getParent());
720 uint64_t DestSize = DL.getTypeAllocSize(Dest.getType()->getElementType());
721 uint64_t SrcSize = DL.getTypeAllocSize(Src.getType()->getElementType());
722 LinkFromSrc = SrcSize > DestSize;
726 if (Src.isWeakForLinker()) {
727 assert(!Dest.hasExternalWeakLinkage());
728 assert(!Dest.hasAvailableExternallyLinkage());
730 if (Dest.hasLinkOnceLinkage() && Src.hasWeakLinkage()) {
739 if (Dest.isWeakForLinker()) {
740 assert(Src.hasExternalLinkage());
745 assert(!Src.hasExternalWeakLinkage());
746 assert(!Dest.hasExternalWeakLinkage());
747 assert(Dest.hasExternalLinkage() && Src.hasExternalLinkage() &&
748 "Unexpected linkage type!");
749 return emitError("Linking globals named '" + Src.getName() +
750 "': symbol multiply defined!");
753 /// Loop over all of the linked values to compute type mappings. For example,
754 /// if we link "extern Foo *x" and "Foo *x = NULL", then we have two struct
755 /// types 'Foo' but one got renamed when the module was loaded into the same
757 void ModuleLinker::computeTypeMapping() {
758 for (GlobalValue &SGV : SrcM->globals()) {
759 GlobalValue *DGV = getLinkedToGlobal(&SGV);
763 if (!DGV->hasAppendingLinkage() || !SGV.hasAppendingLinkage()) {
764 TypeMap.addTypeMapping(DGV->getType(), SGV.getType());
768 // Unify the element type of appending arrays.
769 ArrayType *DAT = cast<ArrayType>(DGV->getType()->getElementType());
770 ArrayType *SAT = cast<ArrayType>(SGV.getType()->getElementType());
771 TypeMap.addTypeMapping(DAT->getElementType(), SAT->getElementType());
774 for (GlobalValue &SGV : *SrcM) {
775 if (GlobalValue *DGV = getLinkedToGlobal(&SGV))
776 TypeMap.addTypeMapping(DGV->getType(), SGV.getType());
779 for (GlobalValue &SGV : SrcM->aliases()) {
780 if (GlobalValue *DGV = getLinkedToGlobal(&SGV))
781 TypeMap.addTypeMapping(DGV->getType(), SGV.getType());
784 // Incorporate types by name, scanning all the types in the source module.
785 // At this point, the destination module may have a type "%foo = { i32 }" for
786 // example. When the source module got loaded into the same LLVMContext, if
787 // it had the same type, it would have been renamed to "%foo.42 = { i32 }".
788 std::vector<StructType *> Types = SrcM->getIdentifiedStructTypes();
789 for (StructType *ST : Types) {
793 // Check to see if there is a dot in the name followed by a digit.
794 size_t DotPos = ST->getName().rfind('.');
795 if (DotPos == 0 || DotPos == StringRef::npos ||
796 ST->getName().back() == '.' ||
797 !isdigit(static_cast<unsigned char>(ST->getName()[DotPos + 1])))
800 // Check to see if the destination module has a struct with the prefix name.
801 StructType *DST = DstM->getTypeByName(ST->getName().substr(0, DotPos));
805 // Don't use it if this actually came from the source module. They're in
806 // the same LLVMContext after all. Also don't use it unless the type is
807 // actually used in the destination module. This can happen in situations
812 // %Z = type { %A } %B = type { %C.1 }
813 // %A = type { %B.1, [7 x i8] } %C.1 = type { i8* }
814 // %B.1 = type { %C } %A.2 = type { %B.3, [5 x i8] }
815 // %C = type { i8* } %B.3 = type { %C.1 }
817 // When we link Module B with Module A, the '%B' in Module B is
818 // used. However, that would then use '%C.1'. But when we process '%C.1',
819 // we prefer to take the '%C' version. So we are then left with both
820 // '%C.1' and '%C' being used for the same types. This leads to some
821 // variables using one type and some using the other.
822 if (TypeMap.DstStructTypesSet.hasType(DST))
823 TypeMap.addTypeMapping(DST, ST);
826 // Now that we have discovered all of the type equivalences, get a body for
827 // any 'opaque' types in the dest module that are now resolved.
828 TypeMap.linkDefinedTypeBodies();
831 static void upgradeGlobalArray(GlobalVariable *GV) {
832 ArrayType *ATy = cast<ArrayType>(GV->getType()->getElementType());
833 StructType *OldTy = cast<StructType>(ATy->getElementType());
834 assert(OldTy->getNumElements() == 2 && "Expected to upgrade from 2 elements");
836 // Get the upgraded 3 element type.
837 PointerType *VoidPtrTy = Type::getInt8Ty(GV->getContext())->getPointerTo();
838 Type *Tys[3] = {OldTy->getElementType(0), OldTy->getElementType(1),
840 StructType *NewTy = StructType::get(GV->getContext(), Tys, false);
842 // Build new constants with a null third field filled in.
843 Constant *OldInitC = GV->getInitializer();
844 ConstantArray *OldInit = dyn_cast<ConstantArray>(OldInitC);
845 if (!OldInit && !isa<ConstantAggregateZero>(OldInitC))
846 // Invalid initializer; give up.
848 std::vector<Constant *> Initializers;
849 if (OldInit && OldInit->getNumOperands()) {
850 Value *Null = Constant::getNullValue(VoidPtrTy);
851 for (Use &U : OldInit->operands()) {
852 ConstantStruct *Init = cast<ConstantStruct>(U.get());
853 Initializers.push_back(ConstantStruct::get(
854 NewTy, Init->getOperand(0), Init->getOperand(1), Null, nullptr));
857 assert(Initializers.size() == ATy->getNumElements() &&
858 "Failed to copy all array elements");
860 // Replace the old GV with a new one.
861 ATy = ArrayType::get(NewTy, Initializers.size());
862 Constant *NewInit = ConstantArray::get(ATy, Initializers);
863 GlobalVariable *NewGV = new GlobalVariable(
864 *GV->getParent(), ATy, GV->isConstant(), GV->getLinkage(), NewInit, "",
865 GV, GV->getThreadLocalMode(), GV->getType()->getAddressSpace(),
866 GV->isExternallyInitialized());
867 NewGV->copyAttributesFrom(GV);
869 assert(GV->use_empty() && "program cannot use initializer list");
870 GV->eraseFromParent();
873 void ModuleLinker::upgradeMismatchedGlobalArray(StringRef Name) {
874 // Look for the global arrays.
875 auto *DstGV = dyn_cast_or_null<GlobalVariable>(DstM->getNamedValue(Name));
878 auto *SrcGV = dyn_cast_or_null<GlobalVariable>(SrcM->getNamedValue(Name));
882 // Check if the types already match.
883 auto *DstTy = cast<ArrayType>(DstGV->getType()->getElementType());
885 cast<ArrayType>(TypeMap.get(SrcGV->getType()->getElementType()));
889 // Grab the element types. We can only upgrade an array of a two-field
890 // struct. Only bother if the other one has three-fields.
891 auto *DstEltTy = cast<StructType>(DstTy->getElementType());
892 auto *SrcEltTy = cast<StructType>(SrcTy->getElementType());
893 if (DstEltTy->getNumElements() == 2 && SrcEltTy->getNumElements() == 3) {
894 upgradeGlobalArray(DstGV);
897 if (DstEltTy->getNumElements() == 3 && SrcEltTy->getNumElements() == 2)
898 upgradeGlobalArray(SrcGV);
900 // We can't upgrade any other differences.
903 void ModuleLinker::upgradeMismatchedGlobals() {
904 upgradeMismatchedGlobalArray("llvm.global_ctors");
905 upgradeMismatchedGlobalArray("llvm.global_dtors");
908 /// If there were any appending global variables, link them together now.
909 /// Return true on error.
910 bool ModuleLinker::linkAppendingVarProto(GlobalVariable *DstGV,
911 const GlobalVariable *SrcGV) {
913 if (!SrcGV->hasAppendingLinkage() || !DstGV->hasAppendingLinkage())
914 return emitError("Linking globals named '" + SrcGV->getName() +
915 "': can only link appending global with another appending global!");
917 ArrayType *DstTy = cast<ArrayType>(DstGV->getType()->getElementType());
919 cast<ArrayType>(TypeMap.get(SrcGV->getType()->getElementType()));
920 Type *EltTy = DstTy->getElementType();
922 // Check to see that they two arrays agree on type.
923 if (EltTy != SrcTy->getElementType())
924 return emitError("Appending variables with different element types!");
925 if (DstGV->isConstant() != SrcGV->isConstant())
926 return emitError("Appending variables linked with different const'ness!");
928 if (DstGV->getAlignment() != SrcGV->getAlignment())
930 "Appending variables with different alignment need to be linked!");
932 if (DstGV->getVisibility() != SrcGV->getVisibility())
934 "Appending variables with different visibility need to be linked!");
936 if (DstGV->hasUnnamedAddr() != SrcGV->hasUnnamedAddr())
938 "Appending variables with different unnamed_addr need to be linked!");
940 if (StringRef(DstGV->getSection()) != SrcGV->getSection())
942 "Appending variables with different section name need to be linked!");
944 uint64_t NewSize = DstTy->getNumElements() + SrcTy->getNumElements();
945 ArrayType *NewType = ArrayType::get(EltTy, NewSize);
947 // Create the new global variable.
949 new GlobalVariable(*DstGV->getParent(), NewType, SrcGV->isConstant(),
950 DstGV->getLinkage(), /*init*/nullptr, /*name*/"", DstGV,
951 DstGV->getThreadLocalMode(),
952 DstGV->getType()->getAddressSpace());
954 // Propagate alignment, visibility and section info.
955 copyGVAttributes(NG, DstGV);
957 AppendingVarInfo AVI;
959 AVI.DstInit = DstGV->getInitializer();
960 AVI.SrcInit = SrcGV->getInitializer();
961 AppendingVars.push_back(AVI);
963 // Replace any uses of the two global variables with uses of the new
965 ValueMap[SrcGV] = ConstantExpr::getBitCast(NG, TypeMap.get(SrcGV->getType()));
967 DstGV->replaceAllUsesWith(ConstantExpr::getBitCast(NG, DstGV->getType()));
968 DstGV->eraseFromParent();
970 // Track the source variable so we don't try to link it.
971 DoNotLinkFromSource.insert(SrcGV);
976 bool ModuleLinker::linkGlobalValueProto(GlobalValue *SGV) {
977 GlobalValue *DGV = getLinkedToGlobal(SGV);
979 // Handle the ultra special appending linkage case first.
980 if (DGV && DGV->hasAppendingLinkage())
981 return linkAppendingVarProto(cast<GlobalVariable>(DGV),
982 cast<GlobalVariable>(SGV));
984 bool LinkFromSrc = true;
986 GlobalValue::VisibilityTypes Visibility = SGV->getVisibility();
987 bool HasUnnamedAddr = SGV->hasUnnamedAddr();
989 if (const Comdat *SC = SGV->getComdat()) {
990 Comdat::SelectionKind SK;
991 std::tie(SK, LinkFromSrc) = ComdatsChosen[SC];
992 C = DstM->getOrInsertComdat(SC->getName());
993 C->setSelectionKind(SK);
995 if (shouldLinkFromSource(LinkFromSrc, *DGV, *SGV))
1000 // Track the source global so that we don't attempt to copy it over when
1001 // processing global initializers.
1002 DoNotLinkFromSource.insert(SGV);
1005 // Make sure to remember this mapping.
1007 ConstantExpr::getBitCast(DGV, TypeMap.get(SGV->getType()));
1011 Visibility = isLessConstraining(Visibility, DGV->getVisibility())
1012 ? DGV->getVisibility()
1014 HasUnnamedAddr = HasUnnamedAddr && DGV->hasUnnamedAddr();
1017 if (!LinkFromSrc && !DGV)
1024 if (auto *SGVar = dyn_cast<GlobalVariable>(SGV))
1025 NewGV = linkGlobalVariableProto(SGVar);
1026 else if (auto *SF = dyn_cast<Function>(SGV))
1027 NewGV = linkFunctionProto(SF, DGV);
1029 NewGV = linkGlobalAliasProto(cast<GlobalAlias>(SGV));
1036 copyGVAttributes(NewGV, SGV);
1038 NewGV->setUnnamedAddr(HasUnnamedAddr);
1039 NewGV->setVisibility(Visibility);
1041 if (auto *NewGO = dyn_cast<GlobalObject>(NewGV)) {
1043 NewGO->setComdat(C);
1045 if (DGV && DGV->hasCommonLinkage() && SGV->hasCommonLinkage())
1046 NewGO->setAlignment(std::max(DGV->getAlignment(), SGV->getAlignment()));
1049 if (auto *NewGVar = dyn_cast<GlobalVariable>(NewGV)) {
1050 auto *DGVar = dyn_cast_or_null<GlobalVariable>(DGV);
1051 auto *SGVar = dyn_cast<GlobalVariable>(SGV);
1052 if (DGVar && SGVar && DGVar->isDeclaration() && SGVar->isDeclaration() &&
1053 (!DGVar->isConstant() || !SGVar->isConstant()))
1054 NewGVar->setConstant(false);
1057 // Make sure to remember this mapping.
1060 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewGV, DGV->getType()));
1061 DGV->eraseFromParent();
1063 ValueMap[SGV] = NewGV;
1069 /// Loop through the global variables in the src module and merge them into the
1072 ModuleLinker::linkGlobalVariableProto(const GlobalVariable *SGVar) {
1073 // No linking to be performed or linking from the source: simply create an
1074 // identical version of the symbol over in the dest module... the
1075 // initializer will be filled in later by LinkGlobalInits.
1076 GlobalVariable *NewDGV = new GlobalVariable(
1077 *DstM, TypeMap.get(SGVar->getType()->getElementType()),
1078 SGVar->isConstant(), SGVar->getLinkage(), /*init*/ nullptr,
1079 SGVar->getName(), /*insertbefore*/ nullptr, SGVar->getThreadLocalMode(),
1080 SGVar->getType()->getAddressSpace());
1085 /// Link the function in the source module into the destination module if
1086 /// needed, setting up mapping information.
1087 GlobalValue *ModuleLinker::linkFunctionProto(const Function *SF,
1089 // If the function is to be lazily linked, don't create it just yet.
1090 // The ValueMaterializerTy will deal with creating it if it's used.
1091 if (!DGV && (SF->hasLocalLinkage() || SF->hasLinkOnceLinkage() ||
1092 SF->hasAvailableExternallyLinkage())) {
1093 DoNotLinkFromSource.insert(SF);
1097 // If there is no linkage to be performed or we are linking from the source,
1099 return Function::Create(TypeMap.get(SF->getFunctionType()), SF->getLinkage(),
1100 SF->getName(), DstM);
1103 /// Set up prototypes for any aliases that come over from the source module.
1104 GlobalValue *ModuleLinker::linkGlobalAliasProto(const GlobalAlias *SGA) {
1105 // If there is no linkage to be performed or we're linking from the source,
1107 auto *PTy = cast<PointerType>(TypeMap.get(SGA->getType()));
1108 return GlobalAlias::create(PTy->getElementType(), PTy->getAddressSpace(),
1109 SGA->getLinkage(), SGA->getName(), DstM);
1112 static void getArrayElements(const Constant *C,
1113 SmallVectorImpl<Constant *> &Dest) {
1114 unsigned NumElements = cast<ArrayType>(C->getType())->getNumElements();
1116 for (unsigned i = 0; i != NumElements; ++i)
1117 Dest.push_back(C->getAggregateElement(i));
1120 void ModuleLinker::linkAppendingVarInit(const AppendingVarInfo &AVI) {
1121 // Merge the initializer.
1122 SmallVector<Constant *, 16> DstElements;
1123 getArrayElements(AVI.DstInit, DstElements);
1125 SmallVector<Constant *, 16> SrcElements;
1126 getArrayElements(AVI.SrcInit, SrcElements);
1128 ArrayType *NewType = cast<ArrayType>(AVI.NewGV->getType()->getElementType());
1130 StringRef Name = AVI.NewGV->getName();
1131 bool IsNewStructor =
1132 (Name == "llvm.global_ctors" || Name == "llvm.global_dtors") &&
1133 cast<StructType>(NewType->getElementType())->getNumElements() == 3;
1135 for (auto *V : SrcElements) {
1136 if (IsNewStructor) {
1137 Constant *Key = V->getAggregateElement(2);
1138 if (DoNotLinkFromSource.count(Key))
1141 DstElements.push_back(
1142 MapValue(V, ValueMap, RF_None, &TypeMap, &ValMaterializer));
1144 if (IsNewStructor) {
1145 NewType = ArrayType::get(NewType->getElementType(), DstElements.size());
1146 AVI.NewGV->mutateType(PointerType::get(NewType, 0));
1149 AVI.NewGV->setInitializer(ConstantArray::get(NewType, DstElements));
1152 /// Update the initializers in the Dest module now that all globals that may be
1153 /// referenced are in Dest.
1154 void ModuleLinker::linkGlobalInits() {
1155 // Loop over all of the globals in the src module, mapping them over as we go
1156 for (Module::const_global_iterator I = SrcM->global_begin(),
1157 E = SrcM->global_end(); I != E; ++I) {
1159 // Only process initialized GV's or ones not already in dest.
1160 if (!I->hasInitializer() || DoNotLinkFromSource.count(I)) continue;
1162 // Grab destination global variable.
1163 GlobalVariable *DGV = cast<GlobalVariable>(ValueMap[I]);
1164 // Figure out what the initializer looks like in the dest module.
1165 DGV->setInitializer(MapValue(I->getInitializer(), ValueMap,
1166 RF_None, &TypeMap, &ValMaterializer));
1170 /// Copy the source function over into the dest function and fix up references
1171 /// to values. At this point we know that Dest is an external function, and
1172 /// that Src is not.
1173 void ModuleLinker::linkFunctionBody(Function *Dst, Function *Src) {
1174 assert(Src && Dst && Dst->isDeclaration() && !Src->isDeclaration());
1176 // Go through and convert function arguments over, remembering the mapping.
1177 Function::arg_iterator DI = Dst->arg_begin();
1178 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end();
1179 I != E; ++I, ++DI) {
1180 DI->setName(I->getName()); // Copy the name over.
1182 // Add a mapping to our mapping.
1186 // Splice the body of the source function into the dest function.
1187 Dst->getBasicBlockList().splice(Dst->end(), Src->getBasicBlockList());
1189 // At this point, all of the instructions and values of the function are now
1190 // copied over. The only problem is that they are still referencing values in
1191 // the Source function as operands. Loop through all of the operands of the
1192 // functions and patch them up to point to the local versions.
1193 for (Function::iterator BB = Dst->begin(), BE = Dst->end(); BB != BE; ++BB)
1194 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
1195 RemapInstruction(I, ValueMap, RF_IgnoreMissingEntries, &TypeMap,
1198 // There is no need to map the arguments anymore.
1199 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end();
1205 /// Insert all of the aliases in Src into the Dest module.
1206 void ModuleLinker::linkAliasBodies() {
1207 for (Module::alias_iterator I = SrcM->alias_begin(), E = SrcM->alias_end();
1209 if (DoNotLinkFromSource.count(I))
1211 if (Constant *Aliasee = I->getAliasee()) {
1212 GlobalAlias *DA = cast<GlobalAlias>(ValueMap[I]);
1214 MapValue(Aliasee, ValueMap, RF_None, &TypeMap, &ValMaterializer);
1215 DA->setAliasee(Val);
1220 /// Insert all of the named MDNodes in Src into the Dest module.
1221 void ModuleLinker::linkNamedMDNodes() {
1222 const NamedMDNode *SrcModFlags = SrcM->getModuleFlagsMetadata();
1223 for (Module::const_named_metadata_iterator I = SrcM->named_metadata_begin(),
1224 E = SrcM->named_metadata_end(); I != E; ++I) {
1225 // Don't link module flags here. Do them separately.
1226 if (&*I == SrcModFlags) continue;
1227 NamedMDNode *DestNMD = DstM->getOrInsertNamedMetadata(I->getName());
1228 // Add Src elements into Dest node.
1229 for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i)
1230 DestNMD->addOperand(MapValue(I->getOperand(i), ValueMap,
1231 RF_None, &TypeMap, &ValMaterializer));
1235 /// Merge the linker flags in Src into the Dest module.
1236 bool ModuleLinker::linkModuleFlagsMetadata() {
1237 // If the source module has no module flags, we are done.
1238 const NamedMDNode *SrcModFlags = SrcM->getModuleFlagsMetadata();
1239 if (!SrcModFlags) return false;
1241 // If the destination module doesn't have module flags yet, then just copy
1242 // over the source module's flags.
1243 NamedMDNode *DstModFlags = DstM->getOrInsertModuleFlagsMetadata();
1244 if (DstModFlags->getNumOperands() == 0) {
1245 for (unsigned I = 0, E = SrcModFlags->getNumOperands(); I != E; ++I)
1246 DstModFlags->addOperand(SrcModFlags->getOperand(I));
1251 // First build a map of the existing module flags and requirements.
1252 DenseMap<MDString*, MDNode*> Flags;
1253 SmallSetVector<MDNode*, 16> Requirements;
1254 for (unsigned I = 0, E = DstModFlags->getNumOperands(); I != E; ++I) {
1255 MDNode *Op = DstModFlags->getOperand(I);
1256 ConstantInt *Behavior = cast<ConstantInt>(Op->getOperand(0));
1257 MDString *ID = cast<MDString>(Op->getOperand(1));
1259 if (Behavior->getZExtValue() == Module::Require) {
1260 Requirements.insert(cast<MDNode>(Op->getOperand(2)));
1266 // Merge in the flags from the source module, and also collect its set of
1268 bool HasErr = false;
1269 for (unsigned I = 0, E = SrcModFlags->getNumOperands(); I != E; ++I) {
1270 MDNode *SrcOp = SrcModFlags->getOperand(I);
1271 ConstantInt *SrcBehavior = cast<ConstantInt>(SrcOp->getOperand(0));
1272 MDString *ID = cast<MDString>(SrcOp->getOperand(1));
1273 MDNode *DstOp = Flags.lookup(ID);
1274 unsigned SrcBehaviorValue = SrcBehavior->getZExtValue();
1276 // If this is a requirement, add it and continue.
1277 if (SrcBehaviorValue == Module::Require) {
1278 // If the destination module does not already have this requirement, add
1280 if (Requirements.insert(cast<MDNode>(SrcOp->getOperand(2)))) {
1281 DstModFlags->addOperand(SrcOp);
1286 // If there is no existing flag with this ID, just add it.
1289 DstModFlags->addOperand(SrcOp);
1293 // Otherwise, perform a merge.
1294 ConstantInt *DstBehavior = cast<ConstantInt>(DstOp->getOperand(0));
1295 unsigned DstBehaviorValue = DstBehavior->getZExtValue();
1297 // If either flag has override behavior, handle it first.
1298 if (DstBehaviorValue == Module::Override) {
1299 // Diagnose inconsistent flags which both have override behavior.
1300 if (SrcBehaviorValue == Module::Override &&
1301 SrcOp->getOperand(2) != DstOp->getOperand(2)) {
1302 HasErr |= emitError("linking module flags '" + ID->getString() +
1303 "': IDs have conflicting override values");
1306 } else if (SrcBehaviorValue == Module::Override) {
1307 // Update the destination flag to that of the source.
1308 DstOp->replaceOperandWith(0, SrcBehavior);
1309 DstOp->replaceOperandWith(2, SrcOp->getOperand(2));
1313 // Diagnose inconsistent merge behavior types.
1314 if (SrcBehaviorValue != DstBehaviorValue) {
1315 HasErr |= emitError("linking module flags '" + ID->getString() +
1316 "': IDs have conflicting behaviors");
1320 // Perform the merge for standard behavior types.
1321 switch (SrcBehaviorValue) {
1322 case Module::Require:
1323 case Module::Override: llvm_unreachable("not possible");
1324 case Module::Error: {
1325 // Emit an error if the values differ.
1326 if (SrcOp->getOperand(2) != DstOp->getOperand(2)) {
1327 HasErr |= emitError("linking module flags '" + ID->getString() +
1328 "': IDs have conflicting values");
1332 case Module::Warning: {
1333 // Emit a warning if the values differ.
1334 if (SrcOp->getOperand(2) != DstOp->getOperand(2)) {
1335 emitWarning("linking module flags '" + ID->getString() +
1336 "': IDs have conflicting values");
1340 case Module::Append: {
1341 MDNode *DstValue = cast<MDNode>(DstOp->getOperand(2));
1342 MDNode *SrcValue = cast<MDNode>(SrcOp->getOperand(2));
1343 unsigned NumOps = DstValue->getNumOperands() + SrcValue->getNumOperands();
1344 Value **VP, **Values = VP = new Value*[NumOps];
1345 for (unsigned i = 0, e = DstValue->getNumOperands(); i != e; ++i, ++VP)
1346 *VP = DstValue->getOperand(i);
1347 for (unsigned i = 0, e = SrcValue->getNumOperands(); i != e; ++i, ++VP)
1348 *VP = SrcValue->getOperand(i);
1349 DstOp->replaceOperandWith(2, MDNode::get(DstM->getContext(),
1350 ArrayRef<Value*>(Values,
1355 case Module::AppendUnique: {
1356 SmallSetVector<Value*, 16> Elts;
1357 MDNode *DstValue = cast<MDNode>(DstOp->getOperand(2));
1358 MDNode *SrcValue = cast<MDNode>(SrcOp->getOperand(2));
1359 for (unsigned i = 0, e = DstValue->getNumOperands(); i != e; ++i)
1360 Elts.insert(DstValue->getOperand(i));
1361 for (unsigned i = 0, e = SrcValue->getNumOperands(); i != e; ++i)
1362 Elts.insert(SrcValue->getOperand(i));
1363 DstOp->replaceOperandWith(2, MDNode::get(DstM->getContext(),
1364 ArrayRef<Value*>(Elts.begin(),
1371 // Check all of the requirements.
1372 for (unsigned I = 0, E = Requirements.size(); I != E; ++I) {
1373 MDNode *Requirement = Requirements[I];
1374 MDString *Flag = cast<MDString>(Requirement->getOperand(0));
1375 Value *ReqValue = Requirement->getOperand(1);
1377 MDNode *Op = Flags[Flag];
1378 if (!Op || Op->getOperand(2) != ReqValue) {
1379 HasErr |= emitError("linking module flags '" + Flag->getString() +
1380 "': does not have the required value");
1388 bool ModuleLinker::run() {
1389 assert(DstM && "Null destination module");
1390 assert(SrcM && "Null source module");
1392 // Inherit the target data from the source module if the destination module
1393 // doesn't have one already.
1394 if (!DstM->getDataLayout() && SrcM->getDataLayout())
1395 DstM->setDataLayout(SrcM->getDataLayout());
1397 // Copy the target triple from the source to dest if the dest's is empty.
1398 if (DstM->getTargetTriple().empty() && !SrcM->getTargetTriple().empty())
1399 DstM->setTargetTriple(SrcM->getTargetTriple());
1401 if (SrcM->getDataLayout() && DstM->getDataLayout() &&
1402 *SrcM->getDataLayout() != *DstM->getDataLayout()) {
1403 emitWarning("Linking two modules of different data layouts: '" +
1404 SrcM->getModuleIdentifier() + "' is '" +
1405 SrcM->getDataLayoutStr() + "' whereas '" +
1406 DstM->getModuleIdentifier() + "' is '" +
1407 DstM->getDataLayoutStr() + "'\n");
1409 if (!SrcM->getTargetTriple().empty() &&
1410 DstM->getTargetTriple() != SrcM->getTargetTriple()) {
1411 emitWarning("Linking two modules of different target triples: " +
1412 SrcM->getModuleIdentifier() + "' is '" +
1413 SrcM->getTargetTriple() + "' whereas '" +
1414 DstM->getModuleIdentifier() + "' is '" +
1415 DstM->getTargetTriple() + "'\n");
1418 // Append the module inline asm string.
1419 if (!SrcM->getModuleInlineAsm().empty()) {
1420 if (DstM->getModuleInlineAsm().empty())
1421 DstM->setModuleInlineAsm(SrcM->getModuleInlineAsm());
1423 DstM->setModuleInlineAsm(DstM->getModuleInlineAsm()+"\n"+
1424 SrcM->getModuleInlineAsm());
1427 // Loop over all of the linked values to compute type mappings.
1428 computeTypeMapping();
1430 ComdatsChosen.clear();
1431 for (const auto &SMEC : SrcM->getComdatSymbolTable()) {
1432 const Comdat &C = SMEC.getValue();
1433 if (ComdatsChosen.count(&C))
1435 Comdat::SelectionKind SK;
1437 if (getComdatResult(&C, SK, LinkFromSrc))
1439 ComdatsChosen[&C] = std::make_pair(SK, LinkFromSrc);
1442 // Upgrade mismatched global arrays.
1443 upgradeMismatchedGlobals();
1445 // Insert all of the globals in src into the DstM module... without linking
1446 // initializers (which could refer to functions not yet mapped over).
1447 for (Module::global_iterator I = SrcM->global_begin(),
1448 E = SrcM->global_end(); I != E; ++I)
1449 if (linkGlobalValueProto(I))
1452 // Link the functions together between the two modules, without doing function
1453 // bodies... this just adds external function prototypes to the DstM
1454 // function... We do this so that when we begin processing function bodies,
1455 // all of the global values that may be referenced are available in our
1457 for (Module::iterator I = SrcM->begin(), E = SrcM->end(); I != E; ++I)
1458 if (linkGlobalValueProto(I))
1461 // If there were any aliases, link them now.
1462 for (Module::alias_iterator I = SrcM->alias_begin(),
1463 E = SrcM->alias_end(); I != E; ++I)
1464 if (linkGlobalValueProto(I))
1467 for (unsigned i = 0, e = AppendingVars.size(); i != e; ++i)
1468 linkAppendingVarInit(AppendingVars[i]);
1470 // Link in the function bodies that are defined in the source module into
1472 for (Module::iterator SF = SrcM->begin(), E = SrcM->end(); SF != E; ++SF) {
1473 // Skip if not linking from source.
1474 if (DoNotLinkFromSource.count(SF)) continue;
1476 Function *DF = cast<Function>(ValueMap[SF]);
1478 // Link in the prefix data.
1479 if (SF->hasPrefixData())
1480 DF->setPrefixData(MapValue(
1481 SF->getPrefixData(), ValueMap, RF_None, &TypeMap, &ValMaterializer));
1483 // Link in the prologue data.
1484 if (SF->hasPrologueData())
1485 DF->setPrologueData(MapValue(
1486 SF->getPrologueData(), ValueMap, RF_None, &TypeMap, &ValMaterializer));
1488 // Materialize if needed.
1489 if (std::error_code EC = SF->materialize())
1490 return emitError(EC.message());
1492 // Skip if no body (function is external).
1493 if (SF->isDeclaration())
1496 linkFunctionBody(DF, SF);
1497 SF->Dematerialize();
1500 // Resolve all uses of aliases with aliasees.
1503 // Remap all of the named MDNodes in Src into the DstM module. We do this
1504 // after linking GlobalValues so that MDNodes that reference GlobalValues
1505 // are properly remapped.
1508 // Merge the module flags into the DstM module.
1509 if (linkModuleFlagsMetadata())
1512 // Update the initializers in the DstM module now that all globals that may
1513 // be referenced are in DstM.
1516 // Process vector of lazily linked in functions.
1517 bool LinkedInAnyFunctions;
1519 LinkedInAnyFunctions = false;
1521 for(std::vector<Function*>::iterator I = LazilyLinkFunctions.begin(),
1522 E = LazilyLinkFunctions.end(); I != E; ++I) {
1527 Function *DF = cast<Function>(ValueMap[SF]);
1528 if (SF->hasPrefixData()) {
1529 // Link in the prefix data.
1530 DF->setPrefixData(MapValue(SF->getPrefixData(),
1537 // Materialize if needed.
1538 if (std::error_code EC = SF->materialize())
1539 return emitError(EC.message());
1541 // Skip if no body (function is external).
1542 if (SF->isDeclaration())
1545 // Erase from vector *before* the function body is linked - linkFunctionBody could
1547 LazilyLinkFunctions.erase(I);
1549 // Link in function body.
1550 linkFunctionBody(DF, SF);
1551 SF->Dematerialize();
1553 // Set flag to indicate we may have more functions to lazily link in
1554 // since we linked in a function.
1555 LinkedInAnyFunctions = true;
1558 } while (LinkedInAnyFunctions);
1563 Linker::StructTypeKeyInfo::KeyTy::KeyTy(ArrayRef<Type *> E, bool P)
1564 : ETypes(E), IsPacked(P) {}
1566 Linker::StructTypeKeyInfo::KeyTy::KeyTy(const StructType *ST)
1567 : ETypes(ST->elements()), IsPacked(ST->isPacked()) {}
1569 bool Linker::StructTypeKeyInfo::KeyTy::operator==(const KeyTy &That) const {
1570 if (IsPacked != That.IsPacked)
1572 if (ETypes != That.ETypes)
1577 bool Linker::StructTypeKeyInfo::KeyTy::operator!=(const KeyTy &That) const {
1578 return !this->operator==(That);
1581 StructType *Linker::StructTypeKeyInfo::getEmptyKey() {
1582 return DenseMapInfo<StructType *>::getEmptyKey();
1585 StructType *Linker::StructTypeKeyInfo::getTombstoneKey() {
1586 return DenseMapInfo<StructType *>::getTombstoneKey();
1589 unsigned Linker::StructTypeKeyInfo::getHashValue(const KeyTy &Key) {
1590 return hash_combine(hash_combine_range(Key.ETypes.begin(), Key.ETypes.end()),
1594 unsigned Linker::StructTypeKeyInfo::getHashValue(const StructType *ST) {
1595 return getHashValue(KeyTy(ST));
1598 bool Linker::StructTypeKeyInfo::isEqual(const KeyTy &LHS,
1599 const StructType *RHS) {
1600 if (RHS == getEmptyKey() || RHS == getTombstoneKey())
1602 return LHS == KeyTy(RHS);
1605 bool Linker::StructTypeKeyInfo::isEqual(const StructType *LHS,
1606 const StructType *RHS) {
1607 if (RHS == getEmptyKey())
1608 return LHS == getEmptyKey();
1610 if (RHS == getTombstoneKey())
1611 return LHS == getTombstoneKey();
1613 return KeyTy(LHS) == KeyTy(RHS);
1616 void Linker::IdentifiedStructTypeSet::addNonOpaque(StructType *Ty) {
1617 assert(!Ty->isOpaque());
1618 bool &Entry = NonOpaqueStructTypes[Ty];
1622 void Linker::IdentifiedStructTypeSet::addOpaque(StructType *Ty) {
1623 assert(Ty->isOpaque());
1624 OpaqueStructTypes.insert(Ty);
1628 Linker::IdentifiedStructTypeSet::findNonOpaque(ArrayRef<Type *> ETypes,
1630 Linker::StructTypeKeyInfo::KeyTy Key(ETypes, IsPacked);
1631 auto I = NonOpaqueStructTypes.find_as(Key);
1632 if (I == NonOpaqueStructTypes.end())
1637 bool Linker::IdentifiedStructTypeSet::hasType(StructType *Ty) {
1639 return OpaqueStructTypes.count(Ty);
1640 auto I = NonOpaqueStructTypes.find(Ty);
1641 if (I == NonOpaqueStructTypes.end())
1643 return I->first == Ty;
1646 void Linker::init(Module *M, DiagnosticHandlerFunction DiagnosticHandler) {
1647 this->Composite = M;
1648 this->DiagnosticHandler = DiagnosticHandler;
1650 TypeFinder StructTypes;
1651 StructTypes.run(*M, true);
1652 for (StructType *Ty : StructTypes) {
1654 IdentifiedStructTypes.addOpaque(Ty);
1656 IdentifiedStructTypes.addNonOpaque(Ty);
1660 Linker::Linker(Module *M, DiagnosticHandlerFunction DiagnosticHandler) {
1661 init(M, DiagnosticHandler);
1664 Linker::Linker(Module *M) {
1665 init(M, [this](const DiagnosticInfo &DI) {
1666 Composite->getContext().diagnose(DI);
1673 void Linker::deleteModule() {
1675 Composite = nullptr;
1678 bool Linker::linkInModule(Module *Src) {
1679 ModuleLinker TheLinker(Composite, IdentifiedStructTypes, Src,
1681 return TheLinker.run();
1684 //===----------------------------------------------------------------------===//
1685 // LinkModules entrypoint.
1686 //===----------------------------------------------------------------------===//
1688 /// This function links two modules together, with the resulting Dest module
1689 /// modified to be the composite of the two input modules. If an error occurs,
1690 /// true is returned and ErrorMsg (if not null) is set to indicate the problem.
1691 /// Upon failure, the Dest module could be in a modified state, and shouldn't be
1692 /// relied on to be consistent.
1693 bool Linker::LinkModules(Module *Dest, Module *Src,
1694 DiagnosticHandlerFunction DiagnosticHandler) {
1695 Linker L(Dest, DiagnosticHandler);
1696 return L.linkInModule(Src);
1699 bool Linker::LinkModules(Module *Dest, Module *Src) {
1701 return L.linkInModule(Src);
1704 //===----------------------------------------------------------------------===//
1706 //===----------------------------------------------------------------------===//
1708 LLVMBool LLVMLinkModules(LLVMModuleRef Dest, LLVMModuleRef Src,
1709 LLVMLinkerMode Mode, char **OutMessages) {
1710 Module *D = unwrap(Dest);
1711 std::string Message;
1712 raw_string_ostream Stream(Message);
1713 DiagnosticPrinterRawOStream DP(Stream);
1715 LLVMBool Result = Linker::LinkModules(
1716 D, unwrap(Src), [&](const DiagnosticInfo &DI) { DI.print(DP); });
1718 if (OutMessages && Result)
1719 *OutMessages = strdup(Message.c_str());