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/SetVector.h"
17 #include "llvm/ADT/SmallString.h"
18 #include "llvm/ADT/Triple.h"
19 #include "llvm/IR/Constants.h"
20 #include "llvm/IR/DiagnosticInfo.h"
21 #include "llvm/IR/DiagnosticPrinter.h"
22 #include "llvm/IR/LLVMContext.h"
23 #include "llvm/IR/Module.h"
24 #include "llvm/IR/TypeFinder.h"
25 #include "llvm/Transforms/Utils/Cloning.h"
28 //===----------------------------------------------------------------------===//
29 // TypeMap implementation.
30 //===----------------------------------------------------------------------===//
33 class TypeMapTy : public ValueMapTypeRemapper {
34 /// This is a mapping from a source type to a destination type to use.
35 DenseMap<Type *, Type *> MappedTypes;
37 /// When checking to see if two subgraphs are isomorphic, we speculatively
38 /// add types to MappedTypes, but keep track of them here in case we need to
40 SmallVector<Type *, 16> SpeculativeTypes;
42 SmallVector<StructType *, 16> SpeculativeDstOpaqueTypes;
44 /// This is a list of non-opaque structs in the source module that are mapped
45 /// to an opaque struct in the destination module.
46 SmallVector<StructType *, 16> SrcDefinitionsToResolve;
48 /// This is the set of opaque types in the destination modules who are
49 /// getting a body from the source module.
50 SmallPtrSet<StructType *, 16> DstResolvedOpaqueTypes;
53 TypeMapTy(Linker::IdentifiedStructTypeSet &DstStructTypesSet)
54 : DstStructTypesSet(DstStructTypesSet) {}
56 Linker::IdentifiedStructTypeSet &DstStructTypesSet;
57 /// Indicate that the specified type in the destination module is conceptually
58 /// equivalent to the specified type in the source module.
59 void addTypeMapping(Type *DstTy, Type *SrcTy);
61 /// Produce a body for an opaque type in the dest module from a type
62 /// definition in the source module.
63 void linkDefinedTypeBodies();
65 /// Return the mapped type to use for the specified input type from the
67 Type *get(Type *SrcTy);
68 Type *get(Type *SrcTy, SmallPtrSet<StructType *, 8> &Visited);
70 void finishType(StructType *DTy, StructType *STy, ArrayRef<Type *> ETypes);
72 FunctionType *get(FunctionType *T) {
73 return cast<FunctionType>(get((Type *)T));
76 /// Dump out the type map for debugging purposes.
78 for (auto &Pair : MappedTypes) {
79 dbgs() << "TypeMap: ";
80 Pair.first->print(dbgs());
82 Pair.second->print(dbgs());
88 Type *remapType(Type *SrcTy) override { return get(SrcTy); }
90 bool areTypesIsomorphic(Type *DstTy, Type *SrcTy);
94 void TypeMapTy::addTypeMapping(Type *DstTy, Type *SrcTy) {
95 assert(SpeculativeTypes.empty());
96 assert(SpeculativeDstOpaqueTypes.empty());
98 // Check to see if these types are recursively isomorphic and establish a
99 // mapping between them if so.
100 if (!areTypesIsomorphic(DstTy, SrcTy)) {
101 // Oops, they aren't isomorphic. Just discard this request by rolling out
102 // any speculative mappings we've established.
103 for (Type *Ty : SpeculativeTypes)
104 MappedTypes.erase(Ty);
106 SrcDefinitionsToResolve.resize(SrcDefinitionsToResolve.size() -
107 SpeculativeDstOpaqueTypes.size());
108 for (StructType *Ty : SpeculativeDstOpaqueTypes)
109 DstResolvedOpaqueTypes.erase(Ty);
111 for (Type *Ty : SpeculativeTypes)
112 if (auto *STy = dyn_cast<StructType>(Ty))
116 SpeculativeTypes.clear();
117 SpeculativeDstOpaqueTypes.clear();
120 /// Recursively walk this pair of types, returning true if they are isomorphic,
121 /// false if they are not.
122 bool TypeMapTy::areTypesIsomorphic(Type *DstTy, Type *SrcTy) {
123 // Two types with differing kinds are clearly not isomorphic.
124 if (DstTy->getTypeID() != SrcTy->getTypeID())
127 // If we have an entry in the MappedTypes table, then we have our answer.
128 Type *&Entry = MappedTypes[SrcTy];
130 return Entry == DstTy;
132 // Two identical types are clearly isomorphic. Remember this
133 // non-speculatively.
134 if (DstTy == SrcTy) {
139 // Okay, we have two types with identical kinds that we haven't seen before.
141 // If this is an opaque struct type, special case it.
142 if (StructType *SSTy = dyn_cast<StructType>(SrcTy)) {
143 // Mapping an opaque type to any struct, just keep the dest struct.
144 if (SSTy->isOpaque()) {
146 SpeculativeTypes.push_back(SrcTy);
150 // Mapping a non-opaque source type to an opaque dest. If this is the first
151 // type that we're mapping onto this destination type then we succeed. Keep
152 // the dest, but fill it in later. If this is the second (different) type
153 // that we're trying to map onto the same opaque type then we fail.
154 if (cast<StructType>(DstTy)->isOpaque()) {
155 // We can only map one source type onto the opaque destination type.
156 if (!DstResolvedOpaqueTypes.insert(cast<StructType>(DstTy)).second)
158 SrcDefinitionsToResolve.push_back(SSTy);
159 SpeculativeTypes.push_back(SrcTy);
160 SpeculativeDstOpaqueTypes.push_back(cast<StructType>(DstTy));
166 // If the number of subtypes disagree between the two types, then we fail.
167 if (SrcTy->getNumContainedTypes() != DstTy->getNumContainedTypes())
170 // Fail if any of the extra properties (e.g. array size) of the type disagree.
171 if (isa<IntegerType>(DstTy))
172 return false; // bitwidth disagrees.
173 if (PointerType *PT = dyn_cast<PointerType>(DstTy)) {
174 if (PT->getAddressSpace() != cast<PointerType>(SrcTy)->getAddressSpace())
177 } else if (FunctionType *FT = dyn_cast<FunctionType>(DstTy)) {
178 if (FT->isVarArg() != cast<FunctionType>(SrcTy)->isVarArg())
180 } else if (StructType *DSTy = dyn_cast<StructType>(DstTy)) {
181 StructType *SSTy = cast<StructType>(SrcTy);
182 if (DSTy->isLiteral() != SSTy->isLiteral() ||
183 DSTy->isPacked() != SSTy->isPacked())
185 } else if (ArrayType *DATy = dyn_cast<ArrayType>(DstTy)) {
186 if (DATy->getNumElements() != cast<ArrayType>(SrcTy)->getNumElements())
188 } else if (VectorType *DVTy = dyn_cast<VectorType>(DstTy)) {
189 if (DVTy->getNumElements() != cast<VectorType>(SrcTy)->getNumElements())
193 // Otherwise, we speculate that these two types will line up and recursively
194 // check the subelements.
196 SpeculativeTypes.push_back(SrcTy);
198 for (unsigned I = 0, E = SrcTy->getNumContainedTypes(); I != E; ++I)
199 if (!areTypesIsomorphic(DstTy->getContainedType(I),
200 SrcTy->getContainedType(I)))
203 // If everything seems to have lined up, then everything is great.
207 void TypeMapTy::linkDefinedTypeBodies() {
208 SmallVector<Type *, 16> Elements;
209 for (StructType *SrcSTy : SrcDefinitionsToResolve) {
210 StructType *DstSTy = cast<StructType>(MappedTypes[SrcSTy]);
211 assert(DstSTy->isOpaque());
213 // Map the body of the source type over to a new body for the dest type.
214 Elements.resize(SrcSTy->getNumElements());
215 for (unsigned I = 0, E = Elements.size(); I != E; ++I)
216 Elements[I] = get(SrcSTy->getElementType(I));
218 DstSTy->setBody(Elements, SrcSTy->isPacked());
219 DstStructTypesSet.switchToNonOpaque(DstSTy);
221 SrcDefinitionsToResolve.clear();
222 DstResolvedOpaqueTypes.clear();
225 void TypeMapTy::finishType(StructType *DTy, StructType *STy,
226 ArrayRef<Type *> ETypes) {
227 DTy->setBody(ETypes, STy->isPacked());
230 if (STy->hasName()) {
231 SmallString<16> TmpName = STy->getName();
233 DTy->setName(TmpName);
236 DstStructTypesSet.addNonOpaque(DTy);
239 Type *TypeMapTy::get(Type *Ty) {
240 SmallPtrSet<StructType *, 8> Visited;
241 return get(Ty, Visited);
244 Type *TypeMapTy::get(Type *Ty, SmallPtrSet<StructType *, 8> &Visited) {
245 // If we already have an entry for this type, return it.
246 Type **Entry = &MappedTypes[Ty];
250 // These are types that LLVM itself will unique.
251 bool IsUniqued = !isa<StructType>(Ty) || cast<StructType>(Ty)->isLiteral();
255 for (auto &Pair : MappedTypes) {
256 assert(!(Pair.first != Ty && Pair.second == Ty) &&
257 "mapping to a source type");
262 if (!IsUniqued && !Visited.insert(cast<StructType>(Ty)).second) {
263 StructType *DTy = StructType::create(Ty->getContext());
267 // If this is not a recursive type, then just map all of the elements and
268 // then rebuild the type from inside out.
269 SmallVector<Type *, 4> ElementTypes;
271 // If there are no element types to map, then the type is itself. This is
272 // true for the anonymous {} struct, things like 'float', integers, etc.
273 if (Ty->getNumContainedTypes() == 0 && IsUniqued)
276 // Remap all of the elements, keeping track of whether any of them change.
277 bool AnyChange = false;
278 ElementTypes.resize(Ty->getNumContainedTypes());
279 for (unsigned I = 0, E = Ty->getNumContainedTypes(); I != E; ++I) {
280 ElementTypes[I] = get(Ty->getContainedType(I), Visited);
281 AnyChange |= ElementTypes[I] != Ty->getContainedType(I);
284 // If we found our type while recursively processing stuff, just use it.
285 Entry = &MappedTypes[Ty];
287 if (auto *DTy = dyn_cast<StructType>(*Entry)) {
288 if (DTy->isOpaque()) {
289 auto *STy = cast<StructType>(Ty);
290 finishType(DTy, STy, ElementTypes);
296 // If all of the element types mapped directly over and the type is not
297 // a nomed struct, then the type is usable as-is.
298 if (!AnyChange && IsUniqued)
301 // Otherwise, rebuild a modified type.
302 switch (Ty->getTypeID()) {
304 llvm_unreachable("unknown derived type to remap");
305 case Type::ArrayTyID:
306 return *Entry = ArrayType::get(ElementTypes[0],
307 cast<ArrayType>(Ty)->getNumElements());
308 case Type::VectorTyID:
309 return *Entry = VectorType::get(ElementTypes[0],
310 cast<VectorType>(Ty)->getNumElements());
311 case Type::PointerTyID:
312 return *Entry = PointerType::get(ElementTypes[0],
313 cast<PointerType>(Ty)->getAddressSpace());
314 case Type::FunctionTyID:
315 return *Entry = FunctionType::get(ElementTypes[0],
316 makeArrayRef(ElementTypes).slice(1),
317 cast<FunctionType>(Ty)->isVarArg());
318 case Type::StructTyID: {
319 auto *STy = cast<StructType>(Ty);
320 bool IsPacked = STy->isPacked();
322 return *Entry = StructType::get(Ty->getContext(), ElementTypes, IsPacked);
324 // If the type is opaque, we can just use it directly.
325 if (STy->isOpaque()) {
326 DstStructTypesSet.addOpaque(STy);
330 if (StructType *OldT =
331 DstStructTypesSet.findNonOpaque(ElementTypes, IsPacked)) {
333 return *Entry = OldT;
337 DstStructTypesSet.addNonOpaque(STy);
341 StructType *DTy = StructType::create(Ty->getContext());
342 finishType(DTy, STy, ElementTypes);
348 //===----------------------------------------------------------------------===//
349 // ModuleLinker implementation.
350 //===----------------------------------------------------------------------===//
355 /// Creates prototypes for functions that are lazily linked on the fly. This
356 /// speeds up linking for modules with many/ lazily linked functions of which
358 class ValueMaterializerTy final : public ValueMaterializer {
359 ModuleLinker *ModLinker;
362 ValueMaterializerTy(ModuleLinker *ModLinker) : ModLinker(ModLinker) {}
364 Value *materializeDeclFor(Value *V) override;
365 void materializeInitFor(GlobalValue *New, GlobalValue *Old) override;
368 class LinkDiagnosticInfo : public DiagnosticInfo {
372 LinkDiagnosticInfo(DiagnosticSeverity Severity, const Twine &Msg);
373 void print(DiagnosticPrinter &DP) const override;
375 LinkDiagnosticInfo::LinkDiagnosticInfo(DiagnosticSeverity Severity,
377 : DiagnosticInfo(DK_Linker, Severity), Msg(Msg) {}
378 void LinkDiagnosticInfo::print(DiagnosticPrinter &DP) const { DP << Msg; }
380 /// This is an implementation class for the LinkModules function, which is the
381 /// entrypoint for this file.
387 ValueMaterializerTy ValMaterializer;
389 /// Mapping of values from what they used to be in Src, to what they are now
390 /// in DstM. ValueToValueMapTy is a ValueMap, which involves some overhead
391 /// due to the use of Value handles which the Linker doesn't actually need,
392 /// but this allows us to reuse the ValueMapper code.
393 ValueToValueMapTy ValueMap;
395 // Set of items not to link in from source.
396 SmallPtrSet<const GlobalValue *, 16> DoNotLinkFromSource;
398 DiagnosticHandlerFunction DiagnosticHandler;
400 /// For symbol clashes, prefer those from Src.
403 /// Function index passed into ModuleLinker for using in function
404 /// importing/exporting handling.
405 const FunctionInfoIndex *ImportIndex;
407 /// Function to import from source module, all other functions are
408 /// imported as declarations instead of definitions.
409 DenseSet<const GlobalValue *> *ImportFunction;
411 /// Set to true if the given FunctionInfoIndex contains any functions
412 /// from this source module, in which case we must conservatively assume
413 /// that any of its functions may be imported into another module
414 /// as part of a different backend compilation process.
415 bool HasExportedFunctions = false;
417 /// Set to true when all global value body linking is complete (including
418 /// lazy linking). Used to prevent metadata linking from creating new
420 bool DoneLinkingBodies = false;
422 bool HasError = false;
425 ModuleLinker(Module &DstM, Linker::IdentifiedStructTypeSet &Set, Module &SrcM,
426 DiagnosticHandlerFunction DiagnosticHandler, unsigned Flags,
427 const FunctionInfoIndex *Index = nullptr,
428 DenseSet<const GlobalValue *> *FuncToImport = nullptr)
429 : DstM(DstM), SrcM(SrcM), TypeMap(Set), ValMaterializer(this),
430 DiagnosticHandler(DiagnosticHandler), Flags(Flags), ImportIndex(Index),
431 ImportFunction(FuncToImport) {
432 assert((ImportIndex || !ImportFunction) &&
433 "Expect a FunctionInfoIndex when importing");
434 // If we have a FunctionInfoIndex but no function to import,
435 // then this is the primary module being compiled in a ThinLTO
436 // backend compilation, and we need to see if it has functions that
437 // may be exported to another backend compilation.
438 if (ImportIndex && !ImportFunction)
439 HasExportedFunctions = ImportIndex->hasExportedFunctions(&SrcM);
443 Value *materializeDeclFor(Value *V);
444 void materializeInitFor(GlobalValue *New, GlobalValue *Old);
447 bool shouldOverrideFromSrc() { return Flags & Linker::OverrideFromSrc; }
448 bool shouldLinkOnlyNeeded() { return Flags & Linker::LinkOnlyNeeded; }
449 bool shouldInternalizeLinkedSymbols() {
450 return Flags & Linker::InternalizeLinkedSymbols;
453 /// Handles cloning of a global values from the source module into
454 /// the destination module, including setting the attributes and visibility.
455 GlobalValue *copyGlobalValueProto(TypeMapTy &TypeMap, const GlobalValue *SGV,
456 const GlobalValue *DGV, bool ForDefinition);
458 /// Check if we should promote the given local value to global scope.
459 bool doPromoteLocalToGlobal(const GlobalValue *SGV);
461 bool shouldLinkFromSource(bool &LinkFromSrc, const GlobalValue &Dest,
462 const GlobalValue &Src);
464 /// Helper method for setting a message and returning an error code.
465 bool emitError(const Twine &Message) {
466 DiagnosticHandler(LinkDiagnosticInfo(DS_Error, Message));
471 void emitWarning(const Twine &Message) {
472 DiagnosticHandler(LinkDiagnosticInfo(DS_Warning, Message));
475 bool getComdatLeader(Module &M, StringRef ComdatName,
476 const GlobalVariable *&GVar);
477 bool computeResultingSelectionKind(StringRef ComdatName,
478 Comdat::SelectionKind Src,
479 Comdat::SelectionKind Dst,
480 Comdat::SelectionKind &Result,
482 std::map<const Comdat *, std::pair<Comdat::SelectionKind, bool>>
484 bool getComdatResult(const Comdat *SrcC, Comdat::SelectionKind &SK,
486 // Keep track of the global value members of each comdat in source.
487 DenseMap<const Comdat *, std::vector<GlobalValue *>> ComdatMembers;
489 /// Given a global in the source module, return the global in the
490 /// destination module that is being linked to, if any.
491 GlobalValue *getLinkedToGlobal(const GlobalValue *SrcGV) {
492 // If the source has no name it can't link. If it has local linkage,
493 // there is no name match-up going on.
494 if (!SrcGV->hasName() || GlobalValue::isLocalLinkage(getLinkage(SrcGV)))
497 // Otherwise see if we have a match in the destination module's symtab.
498 GlobalValue *DGV = DstM.getNamedValue(getName(SrcGV));
502 // If we found a global with the same name in the dest module, but it has
503 // internal linkage, we are really not doing any linkage here.
504 if (DGV->hasLocalLinkage())
507 // Otherwise, we do in fact link to the destination global.
511 void computeTypeMapping();
513 void upgradeMismatchedGlobalArray(StringRef Name);
514 void upgradeMismatchedGlobals();
516 bool linkIfNeeded(GlobalValue &GV);
517 bool linkAppendingVarProto(GlobalVariable *DstGV,
518 const GlobalVariable *SrcGV);
520 bool linkGlobalValueProto(GlobalValue *GV);
521 bool linkModuleFlagsMetadata();
523 void linkGlobalInit(GlobalVariable &Dst, GlobalVariable &Src);
524 bool linkFunctionBody(Function &Dst, Function &Src);
525 void linkAliasBody(GlobalAlias &Dst, GlobalAlias &Src);
526 bool linkGlobalValueBody(GlobalValue &Dst, GlobalValue &Src);
528 /// Functions that take care of cloning a specific global value type
529 /// into the destination module.
530 GlobalVariable *copyGlobalVariableProto(TypeMapTy &TypeMap,
531 const GlobalVariable *SGVar);
532 Function *copyFunctionProto(TypeMapTy &TypeMap, const Function *SF);
533 GlobalValue *copyGlobalAliasProto(TypeMapTy &TypeMap, const GlobalAlias *SGA);
535 /// Helper methods to check if we are importing from or potentially
536 /// exporting from the current source module.
537 bool isPerformingImport() { return ImportFunction != nullptr; }
538 bool isModuleExporting() { return HasExportedFunctions; }
540 /// If we are importing from the source module, checks if we should
541 /// import SGV as a definition, otherwise import as a declaration.
542 bool doImportAsDefinition(const GlobalValue *SGV);
544 /// Get the name for SGV that should be used in the linked destination
545 /// module. Specifically, this handles the case where we need to rename
546 /// a local that is being promoted to global scope.
547 std::string getName(const GlobalValue *SGV);
549 /// Get the new linkage for SGV that should be used in the linked destination
550 /// module. Specifically, for ThinLTO importing or exporting it may need
552 GlobalValue::LinkageTypes getLinkage(const GlobalValue *SGV);
554 /// Copies the necessary global value attributes and name from the source
555 /// to the newly cloned global value.
556 void copyGVAttributes(GlobalValue *NewGV, const GlobalValue *SrcGV);
558 /// Updates the visibility for the new global cloned from the source
559 /// and, if applicable, linked with an existing destination global.
560 /// Handles visibility change required for promoted locals.
561 void setVisibility(GlobalValue *NewGV, const GlobalValue *SGV,
562 const GlobalValue *DGV = nullptr);
564 void linkNamedMDNodes();
568 /// The LLVM SymbolTable class autorenames globals that conflict in the symbol
569 /// table. This is good for all clients except for us. Go through the trouble
570 /// to force this back.
571 static void forceRenaming(GlobalValue *GV, StringRef Name) {
572 // If the global doesn't force its name or if it already has the right name,
573 // there is nothing for us to do.
574 // Note that any required local to global promotion should already be done,
575 // so promoted locals will not skip this handling as their linkage is no
577 if (GV->hasLocalLinkage() || GV->getName() == Name)
580 Module *M = GV->getParent();
582 // If there is a conflict, rename the conflict.
583 if (GlobalValue *ConflictGV = M->getNamedValue(Name)) {
584 GV->takeName(ConflictGV);
585 ConflictGV->setName(Name); // This will cause ConflictGV to get renamed
586 assert(ConflictGV->getName() != Name && "forceRenaming didn't work");
588 GV->setName(Name); // Force the name back
592 /// copy additional attributes (those not needed to construct a GlobalValue)
593 /// from the SrcGV to the DestGV.
594 void ModuleLinker::copyGVAttributes(GlobalValue *NewGV,
595 const GlobalValue *SrcGV) {
596 NewGV->copyAttributesFrom(SrcGV);
597 forceRenaming(NewGV, getName(SrcGV));
600 bool ModuleLinker::doImportAsDefinition(const GlobalValue *SGV) {
601 if (!isPerformingImport())
603 auto *GA = dyn_cast<GlobalAlias>(SGV);
605 if (GA->hasWeakAnyLinkage())
607 const GlobalObject *GO = GA->getBaseObject();
608 if (!GO->hasLinkOnceODRLinkage())
610 return doImportAsDefinition(GO);
612 // Always import GlobalVariable definitions, except for the special
613 // case of WeakAny which are imported as ExternalWeak declarations
614 // (see comments in ModuleLinker::getLinkage). The linkage changes
615 // described in ModuleLinker::getLinkage ensure the correct behavior (e.g.
616 // global variables with external linkage are transformed to
617 // available_externally definitions, which are ultimately turned into
618 // declarations after the EliminateAvailableExternally pass).
619 if (isa<GlobalVariable>(SGV) && !SGV->isDeclaration() &&
620 !SGV->hasWeakAnyLinkage())
622 // Only import the function requested for importing.
623 auto *SF = dyn_cast<Function>(SGV);
624 if (SF && ImportFunction->count(SF))
630 bool ModuleLinker::doPromoteLocalToGlobal(const GlobalValue *SGV) {
631 assert(SGV->hasLocalLinkage());
632 // Both the imported references and the original local variable must
634 if (!isPerformingImport() && !isModuleExporting())
637 // Local const variables never need to be promoted unless they are address
638 // taken. The imported uses can simply use the clone created in this module.
639 // For now we are conservative in determining which variables are not
640 // address taken by checking the unnamed addr flag. To be more aggressive,
641 // the address taken information must be checked earlier during parsing
642 // of the module and recorded in the function index for use when importing
644 auto *GVar = dyn_cast<GlobalVariable>(SGV);
645 if (GVar && GVar->isConstant() && GVar->hasUnnamedAddr())
648 // Eventually we only need to promote functions in the exporting module that
649 // are referenced by a potentially exported function (i.e. one that is in the
654 std::string ModuleLinker::getName(const GlobalValue *SGV) {
655 // For locals that must be promoted to global scope, ensure that
656 // the promoted name uniquely identifies the copy in the original module,
657 // using the ID assigned during combined index creation. When importing,
658 // we rename all locals (not just those that are promoted) in order to
659 // avoid naming conflicts between locals imported from different modules.
660 if (SGV->hasLocalLinkage() &&
661 (doPromoteLocalToGlobal(SGV) || isPerformingImport()))
662 return FunctionInfoIndex::getGlobalNameForLocal(
664 ImportIndex->getModuleId(SGV->getParent()->getModuleIdentifier()));
665 return SGV->getName();
668 GlobalValue::LinkageTypes ModuleLinker::getLinkage(const GlobalValue *SGV) {
669 // Any local variable that is referenced by an exported function needs
670 // to be promoted to global scope. Since we don't currently know which
671 // functions reference which local variables/functions, we must treat
672 // all as potentially exported if this module is exporting anything.
673 if (isModuleExporting()) {
674 if (SGV->hasLocalLinkage() && doPromoteLocalToGlobal(SGV))
675 return GlobalValue::ExternalLinkage;
676 return SGV->getLinkage();
679 // Otherwise, if we aren't importing, no linkage change is needed.
680 if (!isPerformingImport())
681 return SGV->getLinkage();
683 switch (SGV->getLinkage()) {
684 case GlobalValue::ExternalLinkage:
685 // External defnitions are converted to available_externally
686 // definitions upon import, so that they are available for inlining
687 // and/or optimization, but are turned into declarations later
688 // during the EliminateAvailableExternally pass.
689 if (doImportAsDefinition(SGV) && !dyn_cast<GlobalAlias>(SGV))
690 return GlobalValue::AvailableExternallyLinkage;
691 // An imported external declaration stays external.
692 return SGV->getLinkage();
694 case GlobalValue::AvailableExternallyLinkage:
695 // An imported available_externally definition converts
696 // to external if imported as a declaration.
697 if (!doImportAsDefinition(SGV))
698 return GlobalValue::ExternalLinkage;
699 // An imported available_externally declaration stays that way.
700 return SGV->getLinkage();
702 case GlobalValue::LinkOnceAnyLinkage:
703 case GlobalValue::LinkOnceODRLinkage:
704 // These both stay the same when importing the definition.
705 // The ThinLTO pass will eventually force-import their definitions.
706 return SGV->getLinkage();
708 case GlobalValue::WeakAnyLinkage:
709 // Can't import weak_any definitions correctly, or we might change the
710 // program semantics, since the linker will pick the first weak_any
711 // definition and importing would change the order they are seen by the
712 // linker. The module linking caller needs to enforce this.
713 assert(!doImportAsDefinition(SGV));
714 // If imported as a declaration, it becomes external_weak.
715 return GlobalValue::ExternalWeakLinkage;
717 case GlobalValue::WeakODRLinkage:
718 // For weak_odr linkage, there is a guarantee that all copies will be
719 // equivalent, so the issue described above for weak_any does not exist,
720 // and the definition can be imported. It can be treated similarly
721 // to an imported externally visible global value.
722 if (doImportAsDefinition(SGV) && !dyn_cast<GlobalAlias>(SGV))
723 return GlobalValue::AvailableExternallyLinkage;
725 return GlobalValue::ExternalLinkage;
727 case GlobalValue::AppendingLinkage:
728 // It would be incorrect to import an appending linkage variable,
729 // since it would cause global constructors/destructors to be
730 // executed multiple times. This should have already been handled
731 // by linkGlobalValueProto.
732 llvm_unreachable("Cannot import appending linkage variable");
734 case GlobalValue::InternalLinkage:
735 case GlobalValue::PrivateLinkage:
736 // If we are promoting the local to global scope, it is handled
737 // similarly to a normal externally visible global.
738 if (doPromoteLocalToGlobal(SGV)) {
739 if (doImportAsDefinition(SGV) && !dyn_cast<GlobalAlias>(SGV))
740 return GlobalValue::AvailableExternallyLinkage;
742 return GlobalValue::ExternalLinkage;
744 // A non-promoted imported local definition stays local.
745 // The ThinLTO pass will eventually force-import their definitions.
746 return SGV->getLinkage();
748 case GlobalValue::ExternalWeakLinkage:
749 // External weak doesn't apply to definitions, must be a declaration.
750 assert(!doImportAsDefinition(SGV));
751 // Linkage stays external_weak.
752 return SGV->getLinkage();
754 case GlobalValue::CommonLinkage:
755 // Linkage stays common on definitions.
756 // The ThinLTO pass will eventually force-import their definitions.
757 return SGV->getLinkage();
760 llvm_unreachable("unknown linkage type");
763 /// Loop through the global variables in the src module and merge them into the
766 ModuleLinker::copyGlobalVariableProto(TypeMapTy &TypeMap,
767 const GlobalVariable *SGVar) {
768 // No linking to be performed or linking from the source: simply create an
769 // identical version of the symbol over in the dest module... the
770 // initializer will be filled in later by LinkGlobalInits.
771 GlobalVariable *NewDGV =
772 new GlobalVariable(DstM, TypeMap.get(SGVar->getType()->getElementType()),
773 SGVar->isConstant(), GlobalValue::ExternalLinkage,
774 /*init*/ nullptr, getName(SGVar),
775 /*insertbefore*/ nullptr, SGVar->getThreadLocalMode(),
776 SGVar->getType()->getAddressSpace());
781 /// Link the function in the source module into the destination module if
782 /// needed, setting up mapping information.
783 Function *ModuleLinker::copyFunctionProto(TypeMapTy &TypeMap,
784 const Function *SF) {
785 // If there is no linkage to be performed or we are linking from the source,
787 return Function::Create(TypeMap.get(SF->getFunctionType()),
788 GlobalValue::ExternalLinkage, getName(SF), &DstM);
791 /// Set up prototypes for any aliases that come over from the source module.
792 GlobalValue *ModuleLinker::copyGlobalAliasProto(TypeMapTy &TypeMap,
793 const GlobalAlias *SGA) {
794 // If there is no linkage to be performed or we're linking from the source,
796 auto *Ty = TypeMap.get(SGA->getValueType());
797 return GlobalAlias::create(Ty, SGA->getType()->getPointerAddressSpace(),
798 GlobalValue::ExternalLinkage, getName(SGA), &DstM);
801 static GlobalValue::VisibilityTypes
802 getMinVisibility(GlobalValue::VisibilityTypes A,
803 GlobalValue::VisibilityTypes B) {
804 if (A == GlobalValue::HiddenVisibility || B == GlobalValue::HiddenVisibility)
805 return GlobalValue::HiddenVisibility;
806 if (A == GlobalValue::ProtectedVisibility ||
807 B == GlobalValue::ProtectedVisibility)
808 return GlobalValue::ProtectedVisibility;
809 return GlobalValue::DefaultVisibility;
812 void ModuleLinker::setVisibility(GlobalValue *NewGV, const GlobalValue *SGV,
813 const GlobalValue *DGV) {
814 GlobalValue::VisibilityTypes Visibility = SGV->getVisibility();
816 Visibility = getMinVisibility(DGV->getVisibility(), Visibility);
817 // For promoted locals, mark them hidden so that they can later be
818 // stripped from the symbol table to reduce bloat.
819 if (SGV->hasLocalLinkage() && doPromoteLocalToGlobal(SGV))
820 Visibility = GlobalValue::HiddenVisibility;
821 NewGV->setVisibility(Visibility);
824 GlobalValue *ModuleLinker::copyGlobalValueProto(TypeMapTy &TypeMap,
825 const GlobalValue *SGV,
826 const GlobalValue *DGV,
827 bool ForDefinition) {
829 if (auto *SGVar = dyn_cast<GlobalVariable>(SGV)) {
830 NewGV = copyGlobalVariableProto(TypeMap, SGVar);
831 } else if (auto *SF = dyn_cast<Function>(SGV)) {
832 NewGV = copyFunctionProto(TypeMap, SF);
835 NewGV = copyGlobalAliasProto(TypeMap, cast<GlobalAlias>(SGV));
837 NewGV = new GlobalVariable(
838 DstM, TypeMap.get(SGV->getType()->getElementType()),
839 /*isConstant*/ false, GlobalValue::ExternalLinkage,
840 /*init*/ nullptr, getName(SGV),
841 /*insertbefore*/ nullptr, SGV->getThreadLocalMode(),
842 SGV->getType()->getAddressSpace());
846 NewGV->setLinkage(getLinkage(SGV));
847 else if (SGV->hasAvailableExternallyLinkage() || SGV->hasWeakLinkage() ||
848 SGV->hasLinkOnceLinkage())
849 NewGV->setLinkage(GlobalValue::ExternalWeakLinkage);
851 copyGVAttributes(NewGV, SGV);
852 setVisibility(NewGV, SGV, DGV);
856 Value *ValueMaterializerTy::materializeDeclFor(Value *V) {
857 return ModLinker->materializeDeclFor(V);
860 Value *ModuleLinker::materializeDeclFor(Value *V) {
861 auto *SGV = dyn_cast<GlobalValue>(V);
865 // If we are done linking global value bodies (i.e. we are performing
866 // metadata linking), don't link in the global value due to this
867 // reference, simply map it to null.
868 if (DoneLinkingBodies)
871 linkGlobalValueProto(SGV);
874 Value *Ret = ValueMap[SGV];
879 void ValueMaterializerTy::materializeInitFor(GlobalValue *New,
881 return ModLinker->materializeInitFor(New, Old);
884 void ModuleLinker::materializeInitFor(GlobalValue *New, GlobalValue *Old) {
885 if (auto *F = dyn_cast<Function>(New)) {
886 if (!F->isDeclaration())
888 } else if (auto *V = dyn_cast<GlobalVariable>(New)) {
889 if (V->hasInitializer())
892 auto *A = cast<GlobalAlias>(New);
897 if (Old->isDeclaration())
900 if (isPerformingImport() && !doImportAsDefinition(Old))
903 if (!New->hasLocalLinkage() && DoNotLinkFromSource.count(Old))
906 linkGlobalValueBody(*New, *Old);
909 bool ModuleLinker::getComdatLeader(Module &M, StringRef ComdatName,
910 const GlobalVariable *&GVar) {
911 const GlobalValue *GVal = M.getNamedValue(ComdatName);
912 if (const auto *GA = dyn_cast_or_null<GlobalAlias>(GVal)) {
913 GVal = GA->getBaseObject();
915 // We cannot resolve the size of the aliasee yet.
916 return emitError("Linking COMDATs named '" + ComdatName +
917 "': COMDAT key involves incomputable alias size.");
920 GVar = dyn_cast_or_null<GlobalVariable>(GVal);
923 "Linking COMDATs named '" + ComdatName +
924 "': GlobalVariable required for data dependent selection!");
929 bool ModuleLinker::computeResultingSelectionKind(StringRef ComdatName,
930 Comdat::SelectionKind Src,
931 Comdat::SelectionKind Dst,
932 Comdat::SelectionKind &Result,
934 // The ability to mix Comdat::SelectionKind::Any with
935 // Comdat::SelectionKind::Largest is a behavior that comes from COFF.
936 bool DstAnyOrLargest = Dst == Comdat::SelectionKind::Any ||
937 Dst == Comdat::SelectionKind::Largest;
938 bool SrcAnyOrLargest = Src == Comdat::SelectionKind::Any ||
939 Src == Comdat::SelectionKind::Largest;
940 if (DstAnyOrLargest && SrcAnyOrLargest) {
941 if (Dst == Comdat::SelectionKind::Largest ||
942 Src == Comdat::SelectionKind::Largest)
943 Result = Comdat::SelectionKind::Largest;
945 Result = Comdat::SelectionKind::Any;
946 } else if (Src == Dst) {
949 return emitError("Linking COMDATs named '" + ComdatName +
950 "': invalid selection kinds!");
954 case Comdat::SelectionKind::Any:
958 case Comdat::SelectionKind::NoDuplicates:
959 return emitError("Linking COMDATs named '" + ComdatName +
960 "': noduplicates has been violated!");
961 case Comdat::SelectionKind::ExactMatch:
962 case Comdat::SelectionKind::Largest:
963 case Comdat::SelectionKind::SameSize: {
964 const GlobalVariable *DstGV;
965 const GlobalVariable *SrcGV;
966 if (getComdatLeader(DstM, ComdatName, DstGV) ||
967 getComdatLeader(SrcM, ComdatName, SrcGV))
970 const DataLayout &DstDL = DstM.getDataLayout();
971 const DataLayout &SrcDL = SrcM.getDataLayout();
973 DstDL.getTypeAllocSize(DstGV->getType()->getPointerElementType());
975 SrcDL.getTypeAllocSize(SrcGV->getType()->getPointerElementType());
976 if (Result == Comdat::SelectionKind::ExactMatch) {
977 if (SrcGV->getInitializer() != DstGV->getInitializer())
978 return emitError("Linking COMDATs named '" + ComdatName +
979 "': ExactMatch violated!");
981 } else if (Result == Comdat::SelectionKind::Largest) {
982 LinkFromSrc = SrcSize > DstSize;
983 } else if (Result == Comdat::SelectionKind::SameSize) {
984 if (SrcSize != DstSize)
985 return emitError("Linking COMDATs named '" + ComdatName +
986 "': SameSize violated!");
989 llvm_unreachable("unknown selection kind");
998 bool ModuleLinker::getComdatResult(const Comdat *SrcC,
999 Comdat::SelectionKind &Result,
1000 bool &LinkFromSrc) {
1001 Comdat::SelectionKind SSK = SrcC->getSelectionKind();
1002 StringRef ComdatName = SrcC->getName();
1003 Module::ComdatSymTabType &ComdatSymTab = DstM.getComdatSymbolTable();
1004 Module::ComdatSymTabType::iterator DstCI = ComdatSymTab.find(ComdatName);
1006 if (DstCI == ComdatSymTab.end()) {
1007 // Use the comdat if it is only available in one of the modules.
1013 const Comdat *DstC = &DstCI->second;
1014 Comdat::SelectionKind DSK = DstC->getSelectionKind();
1015 return computeResultingSelectionKind(ComdatName, SSK, DSK, Result,
1019 bool ModuleLinker::shouldLinkFromSource(bool &LinkFromSrc,
1020 const GlobalValue &Dest,
1021 const GlobalValue &Src) {
1022 // Should we unconditionally use the Src?
1023 if (shouldOverrideFromSrc()) {
1028 // We always have to add Src if it has appending linkage.
1029 if (Src.hasAppendingLinkage()) {
1030 // Caller should have already determined that we can't link from source
1031 // when importing (see comments in linkGlobalValueProto).
1032 assert(!isPerformingImport());
1037 bool SrcIsDeclaration = Src.isDeclarationForLinker();
1038 bool DestIsDeclaration = Dest.isDeclarationForLinker();
1040 if (isPerformingImport()) {
1041 if (isa<Function>(&Src)) {
1042 // For functions, LinkFromSrc iff this is the function requested
1043 // for importing. For variables, decide below normally.
1044 LinkFromSrc = ImportFunction->count(&Src);
1048 // Check if this is an alias with an already existing definition
1049 // in Dest, which must have come from a prior importing pass from
1050 // the same Src module. Unlike imported function and variable
1051 // definitions, which are imported as available_externally and are
1052 // not definitions for the linker, that is not a valid linkage for
1053 // imported aliases which must be definitions. Simply use the existing
1055 if (isa<GlobalAlias>(&Src) && !DestIsDeclaration) {
1056 assert(isa<GlobalAlias>(&Dest));
1057 LinkFromSrc = false;
1062 if (SrcIsDeclaration) {
1063 // If Src is external or if both Src & Dest are external.. Just link the
1064 // external globals, we aren't adding anything.
1065 if (Src.hasDLLImportStorageClass()) {
1066 // If one of GVs is marked as DLLImport, result should be dllimport'ed.
1067 LinkFromSrc = DestIsDeclaration;
1070 // If the Dest is weak, use the source linkage.
1071 LinkFromSrc = Dest.hasExternalWeakLinkage();
1075 if (DestIsDeclaration) {
1076 // If Dest is external but Src is not:
1081 if (Src.hasCommonLinkage()) {
1082 if (Dest.hasLinkOnceLinkage() || Dest.hasWeakLinkage()) {
1087 if (!Dest.hasCommonLinkage()) {
1088 LinkFromSrc = false;
1092 const DataLayout &DL = Dest.getParent()->getDataLayout();
1093 uint64_t DestSize = DL.getTypeAllocSize(Dest.getType()->getElementType());
1094 uint64_t SrcSize = DL.getTypeAllocSize(Src.getType()->getElementType());
1095 LinkFromSrc = SrcSize > DestSize;
1099 if (Src.isWeakForLinker()) {
1100 assert(!Dest.hasExternalWeakLinkage());
1101 assert(!Dest.hasAvailableExternallyLinkage());
1103 if (Dest.hasLinkOnceLinkage() && Src.hasWeakLinkage()) {
1108 LinkFromSrc = false;
1112 if (Dest.isWeakForLinker()) {
1113 assert(Src.hasExternalLinkage());
1118 assert(!Src.hasExternalWeakLinkage());
1119 assert(!Dest.hasExternalWeakLinkage());
1120 assert(Dest.hasExternalLinkage() && Src.hasExternalLinkage() &&
1121 "Unexpected linkage type!");
1122 return emitError("Linking globals named '" + Src.getName() +
1123 "': symbol multiply defined!");
1126 /// Loop over all of the linked values to compute type mappings. For example,
1127 /// if we link "extern Foo *x" and "Foo *x = NULL", then we have two struct
1128 /// types 'Foo' but one got renamed when the module was loaded into the same
1130 void ModuleLinker::computeTypeMapping() {
1131 for (GlobalValue &SGV : SrcM.globals()) {
1132 GlobalValue *DGV = getLinkedToGlobal(&SGV);
1136 if (!DGV->hasAppendingLinkage() || !SGV.hasAppendingLinkage()) {
1137 TypeMap.addTypeMapping(DGV->getType(), SGV.getType());
1141 // Unify the element type of appending arrays.
1142 ArrayType *DAT = cast<ArrayType>(DGV->getType()->getElementType());
1143 ArrayType *SAT = cast<ArrayType>(SGV.getType()->getElementType());
1144 TypeMap.addTypeMapping(DAT->getElementType(), SAT->getElementType());
1147 for (GlobalValue &SGV : SrcM) {
1148 if (GlobalValue *DGV = getLinkedToGlobal(&SGV))
1149 TypeMap.addTypeMapping(DGV->getType(), SGV.getType());
1152 for (GlobalValue &SGV : SrcM.aliases()) {
1153 if (GlobalValue *DGV = getLinkedToGlobal(&SGV))
1154 TypeMap.addTypeMapping(DGV->getType(), SGV.getType());
1157 // Incorporate types by name, scanning all the types in the source module.
1158 // At this point, the destination module may have a type "%foo = { i32 }" for
1159 // example. When the source module got loaded into the same LLVMContext, if
1160 // it had the same type, it would have been renamed to "%foo.42 = { i32 }".
1161 std::vector<StructType *> Types = SrcM.getIdentifiedStructTypes();
1162 for (StructType *ST : Types) {
1166 // Check to see if there is a dot in the name followed by a digit.
1167 size_t DotPos = ST->getName().rfind('.');
1168 if (DotPos == 0 || DotPos == StringRef::npos ||
1169 ST->getName().back() == '.' ||
1170 !isdigit(static_cast<unsigned char>(ST->getName()[DotPos + 1])))
1173 // Check to see if the destination module has a struct with the prefix name.
1174 StructType *DST = DstM.getTypeByName(ST->getName().substr(0, DotPos));
1178 // Don't use it if this actually came from the source module. They're in
1179 // the same LLVMContext after all. Also don't use it unless the type is
1180 // actually used in the destination module. This can happen in situations
1183 // Module A Module B
1184 // -------- --------
1185 // %Z = type { %A } %B = type { %C.1 }
1186 // %A = type { %B.1, [7 x i8] } %C.1 = type { i8* }
1187 // %B.1 = type { %C } %A.2 = type { %B.3, [5 x i8] }
1188 // %C = type { i8* } %B.3 = type { %C.1 }
1190 // When we link Module B with Module A, the '%B' in Module B is
1191 // used. However, that would then use '%C.1'. But when we process '%C.1',
1192 // we prefer to take the '%C' version. So we are then left with both
1193 // '%C.1' and '%C' being used for the same types. This leads to some
1194 // variables using one type and some using the other.
1195 if (TypeMap.DstStructTypesSet.hasType(DST))
1196 TypeMap.addTypeMapping(DST, ST);
1199 // Now that we have discovered all of the type equivalences, get a body for
1200 // any 'opaque' types in the dest module that are now resolved.
1201 TypeMap.linkDefinedTypeBodies();
1204 static void upgradeGlobalArray(GlobalVariable *GV) {
1205 ArrayType *ATy = cast<ArrayType>(GV->getType()->getElementType());
1206 StructType *OldTy = cast<StructType>(ATy->getElementType());
1207 assert(OldTy->getNumElements() == 2 && "Expected to upgrade from 2 elements");
1209 // Get the upgraded 3 element type.
1210 PointerType *VoidPtrTy = Type::getInt8Ty(GV->getContext())->getPointerTo();
1211 Type *Tys[3] = {OldTy->getElementType(0), OldTy->getElementType(1),
1213 StructType *NewTy = StructType::get(GV->getContext(), Tys, false);
1215 // Build new constants with a null third field filled in.
1216 Constant *OldInitC = GV->getInitializer();
1217 ConstantArray *OldInit = dyn_cast<ConstantArray>(OldInitC);
1218 if (!OldInit && !isa<ConstantAggregateZero>(OldInitC))
1219 // Invalid initializer; give up.
1221 std::vector<Constant *> Initializers;
1222 if (OldInit && OldInit->getNumOperands()) {
1223 Value *Null = Constant::getNullValue(VoidPtrTy);
1224 for (Use &U : OldInit->operands()) {
1225 ConstantStruct *Init = cast<ConstantStruct>(U.get());
1226 Initializers.push_back(ConstantStruct::get(
1227 NewTy, Init->getOperand(0), Init->getOperand(1), Null, nullptr));
1230 assert(Initializers.size() == ATy->getNumElements() &&
1231 "Failed to copy all array elements");
1233 // Replace the old GV with a new one.
1234 ATy = ArrayType::get(NewTy, Initializers.size());
1235 Constant *NewInit = ConstantArray::get(ATy, Initializers);
1236 GlobalVariable *NewGV = new GlobalVariable(
1237 *GV->getParent(), ATy, GV->isConstant(), GV->getLinkage(), NewInit, "",
1238 GV, GV->getThreadLocalMode(), GV->getType()->getAddressSpace(),
1239 GV->isExternallyInitialized());
1240 NewGV->copyAttributesFrom(GV);
1241 NewGV->takeName(GV);
1242 assert(GV->use_empty() && "program cannot use initializer list");
1243 GV->eraseFromParent();
1246 void ModuleLinker::upgradeMismatchedGlobalArray(StringRef Name) {
1247 // Look for the global arrays.
1248 auto *DstGV = dyn_cast_or_null<GlobalVariable>(DstM.getNamedValue(Name));
1251 auto *SrcGV = dyn_cast_or_null<GlobalVariable>(SrcM.getNamedValue(Name));
1255 // Check if the types already match.
1256 auto *DstTy = cast<ArrayType>(DstGV->getType()->getElementType());
1258 cast<ArrayType>(TypeMap.get(SrcGV->getType()->getElementType()));
1262 // Grab the element types. We can only upgrade an array of a two-field
1263 // struct. Only bother if the other one has three-fields.
1264 auto *DstEltTy = cast<StructType>(DstTy->getElementType());
1265 auto *SrcEltTy = cast<StructType>(SrcTy->getElementType());
1266 if (DstEltTy->getNumElements() == 2 && SrcEltTy->getNumElements() == 3) {
1267 upgradeGlobalArray(DstGV);
1270 if (DstEltTy->getNumElements() == 3 && SrcEltTy->getNumElements() == 2)
1271 upgradeGlobalArray(SrcGV);
1273 // We can't upgrade any other differences.
1276 void ModuleLinker::upgradeMismatchedGlobals() {
1277 upgradeMismatchedGlobalArray("llvm.global_ctors");
1278 upgradeMismatchedGlobalArray("llvm.global_dtors");
1281 static void getArrayElements(const Constant *C,
1282 SmallVectorImpl<Constant *> &Dest) {
1283 unsigned NumElements = cast<ArrayType>(C->getType())->getNumElements();
1285 for (unsigned i = 0; i != NumElements; ++i)
1286 Dest.push_back(C->getAggregateElement(i));
1289 /// If there were any appending global variables, link them together now.
1290 /// Return true on error.
1291 bool ModuleLinker::linkAppendingVarProto(GlobalVariable *DstGV,
1292 const GlobalVariable *SrcGV) {
1294 cast<ArrayType>(TypeMap.get(SrcGV->getType()->getElementType()));
1295 Type *EltTy = SrcTy->getElementType();
1298 ArrayType *DstTy = cast<ArrayType>(DstGV->getType()->getElementType());
1300 if (!SrcGV->hasAppendingLinkage() || !DstGV->hasAppendingLinkage())
1302 "Linking globals named '" + SrcGV->getName() +
1303 "': can only link appending global with another appending global!");
1305 // Check to see that they two arrays agree on type.
1306 if (EltTy != DstTy->getElementType())
1307 return emitError("Appending variables with different element types!");
1308 if (DstGV->isConstant() != SrcGV->isConstant())
1309 return emitError("Appending variables linked with different const'ness!");
1311 if (DstGV->getAlignment() != SrcGV->getAlignment())
1313 "Appending variables with different alignment need to be linked!");
1315 if (DstGV->getVisibility() != SrcGV->getVisibility())
1317 "Appending variables with different visibility need to be linked!");
1319 if (DstGV->hasUnnamedAddr() != SrcGV->hasUnnamedAddr())
1321 "Appending variables with different unnamed_addr need to be linked!");
1323 if (StringRef(DstGV->getSection()) != SrcGV->getSection())
1325 "Appending variables with different section name need to be linked!");
1328 SmallVector<Constant *, 16> DstElements;
1330 getArrayElements(DstGV->getInitializer(), DstElements);
1332 SmallVector<Constant *, 16> SrcElements;
1333 getArrayElements(SrcGV->getInitializer(), SrcElements);
1335 StringRef Name = SrcGV->getName();
1336 bool IsNewStructor =
1337 (Name == "llvm.global_ctors" || Name == "llvm.global_dtors") &&
1338 cast<StructType>(EltTy)->getNumElements() == 3;
1341 std::remove_if(SrcElements.begin(), SrcElements.end(),
1342 [this](Constant *E) {
1343 auto *Key = dyn_cast<GlobalValue>(
1344 E->getAggregateElement(2)->stripPointerCasts());
1345 return DoNotLinkFromSource.count(Key);
1348 uint64_t NewSize = DstElements.size() + SrcElements.size();
1349 ArrayType *NewType = ArrayType::get(EltTy, NewSize);
1351 // Create the new global variable.
1352 GlobalVariable *NG = new GlobalVariable(
1353 DstM, NewType, SrcGV->isConstant(), SrcGV->getLinkage(),
1354 /*init*/ nullptr, /*name*/ "", DstGV, SrcGV->getThreadLocalMode(),
1355 SrcGV->getType()->getAddressSpace());
1357 // Propagate alignment, visibility and section info.
1358 copyGVAttributes(NG, SrcGV);
1360 // Replace any uses of the two global variables with uses of the new
1362 ValueMap[SrcGV] = ConstantExpr::getBitCast(NG, TypeMap.get(SrcGV->getType()));
1364 for (auto *V : SrcElements) {
1365 DstElements.push_back(
1366 MapValue(V, ValueMap, RF_MoveDistinctMDs, &TypeMap, &ValMaterializer));
1369 NG->setInitializer(ConstantArray::get(NewType, DstElements));
1372 DstGV->replaceAllUsesWith(ConstantExpr::getBitCast(NG, DstGV->getType()));
1373 DstGV->eraseFromParent();
1379 bool ModuleLinker::linkGlobalValueProto(GlobalValue *SGV) {
1380 GlobalValue *DGV = getLinkedToGlobal(SGV);
1382 // Handle the ultra special appending linkage case first.
1383 assert(!DGV || SGV->hasAppendingLinkage() == DGV->hasAppendingLinkage());
1384 if (SGV->hasAppendingLinkage() && isPerformingImport()) {
1385 // Don't want to append to global_ctors list, for example, when we
1386 // are importing for ThinLTO, otherwise the global ctors and dtors
1387 // get executed multiple times for local variables (the latter causing
1389 DoNotLinkFromSource.insert(SGV);
1392 if (SGV->hasAppendingLinkage())
1393 return linkAppendingVarProto(cast_or_null<GlobalVariable>(DGV),
1394 cast<GlobalVariable>(SGV));
1396 bool LinkFromSrc = true;
1397 Comdat *C = nullptr;
1398 bool HasUnnamedAddr = SGV->hasUnnamedAddr();
1400 if (isPerformingImport() && !doImportAsDefinition(SGV)) {
1401 LinkFromSrc = false;
1402 } else if (const Comdat *SC = SGV->getComdat()) {
1403 Comdat::SelectionKind SK;
1404 std::tie(SK, LinkFromSrc) = ComdatsChosen[SC];
1405 C = DstM.getOrInsertComdat(SC->getName());
1406 C->setSelectionKind(SK);
1407 if (SGV->hasLocalLinkage())
1410 if (shouldLinkFromSource(LinkFromSrc, *DGV, *SGV))
1415 // Track the source global so that we don't attempt to copy it over when
1416 // processing global initializers.
1417 DoNotLinkFromSource.insert(SGV);
1420 // Make sure to remember this mapping.
1422 ConstantExpr::getBitCast(DGV, TypeMap.get(SGV->getType()));
1426 HasUnnamedAddr = HasUnnamedAddr && DGV->hasUnnamedAddr();
1429 if (!LinkFromSrc && DGV) {
1431 // When linking from source we setVisibility from copyGlobalValueProto.
1432 setVisibility(NewGV, SGV, DGV);
1434 NewGV = copyGlobalValueProto(TypeMap, SGV, DGV, LinkFromSrc);
1437 NewGV->setUnnamedAddr(HasUnnamedAddr);
1439 if (auto *NewGO = dyn_cast<GlobalObject>(NewGV)) {
1440 if (C && LinkFromSrc)
1441 NewGO->setComdat(C);
1443 if (DGV && DGV->hasCommonLinkage() && SGV->hasCommonLinkage())
1444 NewGO->setAlignment(std::max(DGV->getAlignment(), SGV->getAlignment()));
1447 if (auto *NewGVar = dyn_cast<GlobalVariable>(NewGV)) {
1448 auto *DGVar = dyn_cast_or_null<GlobalVariable>(DGV);
1449 auto *SGVar = dyn_cast<GlobalVariable>(SGV);
1450 if (DGVar && SGVar && DGVar->isDeclaration() && SGVar->isDeclaration() &&
1451 (!DGVar->isConstant() || !SGVar->isConstant()))
1452 NewGVar->setConstant(false);
1455 // Make sure to remember this mapping.
1458 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewGV, DGV->getType()));
1459 DGV->eraseFromParent();
1461 ValueMap[SGV] = NewGV;
1467 /// Update the initializers in the Dest module now that all globals that may be
1468 /// referenced are in Dest.
1469 void ModuleLinker::linkGlobalInit(GlobalVariable &Dst, GlobalVariable &Src) {
1470 // Figure out what the initializer looks like in the dest module.
1471 Dst.setInitializer(MapValue(Src.getInitializer(), ValueMap,
1472 RF_MoveDistinctMDs, &TypeMap, &ValMaterializer));
1475 /// Copy the source function over into the dest function and fix up references
1476 /// to values. At this point we know that Dest is an external function, and
1477 /// that Src is not.
1478 bool ModuleLinker::linkFunctionBody(Function &Dst, Function &Src) {
1479 assert(Dst.isDeclaration() && !Src.isDeclaration());
1481 // Materialize if needed.
1482 if (std::error_code EC = Src.materialize())
1483 return emitError(EC.message());
1485 // Link in the prefix data.
1486 if (Src.hasPrefixData())
1487 Dst.setPrefixData(MapValue(Src.getPrefixData(), ValueMap,
1488 RF_MoveDistinctMDs, &TypeMap, &ValMaterializer));
1490 // Link in the prologue data.
1491 if (Src.hasPrologueData())
1492 Dst.setPrologueData(MapValue(Src.getPrologueData(), ValueMap,
1493 RF_MoveDistinctMDs, &TypeMap,
1496 // Link in the personality function.
1497 if (Src.hasPersonalityFn())
1498 Dst.setPersonalityFn(MapValue(Src.getPersonalityFn(), ValueMap,
1499 RF_MoveDistinctMDs, &TypeMap,
1502 // Go through and convert function arguments over, remembering the mapping.
1503 Function::arg_iterator DI = Dst.arg_begin();
1504 for (Argument &Arg : Src.args()) {
1505 DI->setName(Arg.getName()); // Copy the name over.
1507 // Add a mapping to our mapping.
1508 ValueMap[&Arg] = &*DI;
1512 // Copy over the metadata attachments.
1513 SmallVector<std::pair<unsigned, MDNode *>, 8> MDs;
1514 Src.getAllMetadata(MDs);
1515 for (const auto &I : MDs)
1516 Dst.setMetadata(I.first, MapMetadata(I.second, ValueMap, RF_MoveDistinctMDs,
1517 &TypeMap, &ValMaterializer));
1519 // Splice the body of the source function into the dest function.
1520 Dst.getBasicBlockList().splice(Dst.end(), Src.getBasicBlockList());
1522 // At this point, all of the instructions and values of the function are now
1523 // copied over. The only problem is that they are still referencing values in
1524 // the Source function as operands. Loop through all of the operands of the
1525 // functions and patch them up to point to the local versions.
1526 for (BasicBlock &BB : Dst)
1527 for (Instruction &I : BB)
1528 RemapInstruction(&I, ValueMap,
1529 RF_IgnoreMissingEntries | RF_MoveDistinctMDs, &TypeMap,
1532 // There is no need to map the arguments anymore.
1533 for (Argument &Arg : Src.args())
1534 ValueMap.erase(&Arg);
1536 Src.dematerialize();
1540 void ModuleLinker::linkAliasBody(GlobalAlias &Dst, GlobalAlias &Src) {
1541 Constant *Aliasee = Src.getAliasee();
1542 Constant *Val = MapValue(Aliasee, ValueMap, RF_MoveDistinctMDs, &TypeMap,
1544 Dst.setAliasee(Val);
1547 bool ModuleLinker::linkGlobalValueBody(GlobalValue &Dst, GlobalValue &Src) {
1548 if (const Comdat *SC = Src.getComdat()) {
1549 // To ensure that we don't generate an incomplete comdat group,
1550 // we must materialize and map in any other members that are not
1551 // yet materialized in Dst, which also ensures their definitions
1552 // are linked in. Otherwise, linkonce and other lazy linked GVs will
1553 // not be materialized if they aren't referenced.
1554 for (auto *SGV : ComdatMembers[SC]) {
1555 auto *DGV = cast_or_null<GlobalValue>(ValueMap[SGV]);
1556 if (DGV && !DGV->isDeclaration())
1558 MapValue(SGV, ValueMap, RF_MoveDistinctMDs, &TypeMap, &ValMaterializer);
1561 if (shouldInternalizeLinkedSymbols())
1562 if (auto *DGV = dyn_cast<GlobalValue>(&Dst))
1563 DGV->setLinkage(GlobalValue::InternalLinkage);
1564 if (auto *F = dyn_cast<Function>(&Src))
1565 return linkFunctionBody(cast<Function>(Dst), *F);
1566 if (auto *GVar = dyn_cast<GlobalVariable>(&Src)) {
1567 linkGlobalInit(cast<GlobalVariable>(Dst), *GVar);
1570 linkAliasBody(cast<GlobalAlias>(Dst), cast<GlobalAlias>(Src));
1574 /// Insert all of the named MDNodes in Src into the Dest module.
1575 void ModuleLinker::linkNamedMDNodes() {
1576 const NamedMDNode *SrcModFlags = SrcM.getModuleFlagsMetadata();
1577 for (const NamedMDNode &NMD : SrcM.named_metadata()) {
1578 // Don't link module flags here. Do them separately.
1579 if (&NMD == SrcModFlags)
1581 NamedMDNode *DestNMD = DstM.getOrInsertNamedMetadata(NMD.getName());
1582 // Add Src elements into Dest node.
1583 for (const MDNode *op : NMD.operands())
1584 DestNMD->addOperand(MapMetadata(
1585 op, ValueMap, RF_MoveDistinctMDs | RF_NullMapMissingGlobalValues,
1586 &TypeMap, &ValMaterializer));
1590 /// Merge the linker flags in Src into the Dest module.
1591 bool ModuleLinker::linkModuleFlagsMetadata() {
1592 // If the source module has no module flags, we are done.
1593 const NamedMDNode *SrcModFlags = SrcM.getModuleFlagsMetadata();
1597 // If the destination module doesn't have module flags yet, then just copy
1598 // over the source module's flags.
1599 NamedMDNode *DstModFlags = DstM.getOrInsertModuleFlagsMetadata();
1600 if (DstModFlags->getNumOperands() == 0) {
1601 for (unsigned I = 0, E = SrcModFlags->getNumOperands(); I != E; ++I)
1602 DstModFlags->addOperand(SrcModFlags->getOperand(I));
1607 // First build a map of the existing module flags and requirements.
1608 DenseMap<MDString *, std::pair<MDNode *, unsigned>> Flags;
1609 SmallSetVector<MDNode *, 16> Requirements;
1610 for (unsigned I = 0, E = DstModFlags->getNumOperands(); I != E; ++I) {
1611 MDNode *Op = DstModFlags->getOperand(I);
1612 ConstantInt *Behavior = mdconst::extract<ConstantInt>(Op->getOperand(0));
1613 MDString *ID = cast<MDString>(Op->getOperand(1));
1615 if (Behavior->getZExtValue() == Module::Require) {
1616 Requirements.insert(cast<MDNode>(Op->getOperand(2)));
1618 Flags[ID] = std::make_pair(Op, I);
1622 // Merge in the flags from the source module, and also collect its set of
1624 bool HasErr = false;
1625 for (unsigned I = 0, E = SrcModFlags->getNumOperands(); I != E; ++I) {
1626 MDNode *SrcOp = SrcModFlags->getOperand(I);
1627 ConstantInt *SrcBehavior =
1628 mdconst::extract<ConstantInt>(SrcOp->getOperand(0));
1629 MDString *ID = cast<MDString>(SrcOp->getOperand(1));
1632 std::tie(DstOp, DstIndex) = Flags.lookup(ID);
1633 unsigned SrcBehaviorValue = SrcBehavior->getZExtValue();
1635 // If this is a requirement, add it and continue.
1636 if (SrcBehaviorValue == Module::Require) {
1637 // If the destination module does not already have this requirement, add
1639 if (Requirements.insert(cast<MDNode>(SrcOp->getOperand(2)))) {
1640 DstModFlags->addOperand(SrcOp);
1645 // If there is no existing flag with this ID, just add it.
1647 Flags[ID] = std::make_pair(SrcOp, DstModFlags->getNumOperands());
1648 DstModFlags->addOperand(SrcOp);
1652 // Otherwise, perform a merge.
1653 ConstantInt *DstBehavior =
1654 mdconst::extract<ConstantInt>(DstOp->getOperand(0));
1655 unsigned DstBehaviorValue = DstBehavior->getZExtValue();
1657 // If either flag has override behavior, handle it first.
1658 if (DstBehaviorValue == Module::Override) {
1659 // Diagnose inconsistent flags which both have override behavior.
1660 if (SrcBehaviorValue == Module::Override &&
1661 SrcOp->getOperand(2) != DstOp->getOperand(2)) {
1662 HasErr |= emitError("linking module flags '" + ID->getString() +
1663 "': IDs have conflicting override values");
1666 } else if (SrcBehaviorValue == Module::Override) {
1667 // Update the destination flag to that of the source.
1668 DstModFlags->setOperand(DstIndex, SrcOp);
1669 Flags[ID].first = SrcOp;
1673 // Diagnose inconsistent merge behavior types.
1674 if (SrcBehaviorValue != DstBehaviorValue) {
1675 HasErr |= emitError("linking module flags '" + ID->getString() +
1676 "': IDs have conflicting behaviors");
1680 auto replaceDstValue = [&](MDNode *New) {
1681 Metadata *FlagOps[] = {DstOp->getOperand(0), ID, New};
1682 MDNode *Flag = MDNode::get(DstM.getContext(), FlagOps);
1683 DstModFlags->setOperand(DstIndex, Flag);
1684 Flags[ID].first = Flag;
1687 // Perform the merge for standard behavior types.
1688 switch (SrcBehaviorValue) {
1689 case Module::Require:
1690 case Module::Override:
1691 llvm_unreachable("not possible");
1692 case Module::Error: {
1693 // Emit an error if the values differ.
1694 if (SrcOp->getOperand(2) != DstOp->getOperand(2)) {
1695 HasErr |= emitError("linking module flags '" + ID->getString() +
1696 "': IDs have conflicting values");
1700 case Module::Warning: {
1701 // Emit a warning if the values differ.
1702 if (SrcOp->getOperand(2) != DstOp->getOperand(2)) {
1703 emitWarning("linking module flags '" + ID->getString() +
1704 "': IDs have conflicting values");
1708 case Module::Append: {
1709 MDNode *DstValue = cast<MDNode>(DstOp->getOperand(2));
1710 MDNode *SrcValue = cast<MDNode>(SrcOp->getOperand(2));
1711 SmallVector<Metadata *, 8> MDs;
1712 MDs.reserve(DstValue->getNumOperands() + SrcValue->getNumOperands());
1713 MDs.append(DstValue->op_begin(), DstValue->op_end());
1714 MDs.append(SrcValue->op_begin(), SrcValue->op_end());
1716 replaceDstValue(MDNode::get(DstM.getContext(), MDs));
1719 case Module::AppendUnique: {
1720 SmallSetVector<Metadata *, 16> Elts;
1721 MDNode *DstValue = cast<MDNode>(DstOp->getOperand(2));
1722 MDNode *SrcValue = cast<MDNode>(SrcOp->getOperand(2));
1723 Elts.insert(DstValue->op_begin(), DstValue->op_end());
1724 Elts.insert(SrcValue->op_begin(), SrcValue->op_end());
1726 replaceDstValue(MDNode::get(DstM.getContext(),
1727 makeArrayRef(Elts.begin(), Elts.end())));
1733 // Check all of the requirements.
1734 for (unsigned I = 0, E = Requirements.size(); I != E; ++I) {
1735 MDNode *Requirement = Requirements[I];
1736 MDString *Flag = cast<MDString>(Requirement->getOperand(0));
1737 Metadata *ReqValue = Requirement->getOperand(1);
1739 MDNode *Op = Flags[Flag].first;
1740 if (!Op || Op->getOperand(2) != ReqValue) {
1741 HasErr |= emitError("linking module flags '" + Flag->getString() +
1742 "': does not have the required value");
1750 // This function returns true if the triples match.
1751 static bool triplesMatch(const Triple &T0, const Triple &T1) {
1752 // If vendor is apple, ignore the version number.
1753 if (T0.getVendor() == Triple::Apple)
1754 return T0.getArch() == T1.getArch() && T0.getSubArch() == T1.getSubArch() &&
1755 T0.getVendor() == T1.getVendor() && T0.getOS() == T1.getOS();
1760 // This function returns the merged triple.
1761 static std::string mergeTriples(const Triple &SrcTriple,
1762 const Triple &DstTriple) {
1763 // If vendor is apple, pick the triple with the larger version number.
1764 if (SrcTriple.getVendor() == Triple::Apple)
1765 if (DstTriple.isOSVersionLT(SrcTriple))
1766 return SrcTriple.str();
1768 return DstTriple.str();
1771 bool ModuleLinker::linkIfNeeded(GlobalValue &GV) {
1772 GlobalValue *DGV = getLinkedToGlobal(&GV);
1774 if (shouldLinkOnlyNeeded() && !(DGV && DGV->isDeclaration()))
1777 if (DGV && !GV.hasLocalLinkage()) {
1778 GlobalValue::VisibilityTypes Visibility =
1779 getMinVisibility(DGV->getVisibility(), GV.getVisibility());
1780 DGV->setVisibility(Visibility);
1781 GV.setVisibility(Visibility);
1784 if (const Comdat *SC = GV.getComdat()) {
1786 Comdat::SelectionKind SK;
1787 std::tie(SK, LinkFromSrc) = ComdatsChosen[SC];
1789 DoNotLinkFromSource.insert(&GV);
1794 if (!DGV && !shouldOverrideFromSrc() &&
1795 (GV.hasLocalLinkage() || GV.hasLinkOnceLinkage() ||
1796 GV.hasAvailableExternallyLinkage())) {
1799 MapValue(&GV, ValueMap, RF_MoveDistinctMDs, &TypeMap, &ValMaterializer);
1803 bool ModuleLinker::run() {
1804 // Inherit the target data from the source module if the destination module
1805 // doesn't have one already.
1806 if (DstM.getDataLayout().isDefault())
1807 DstM.setDataLayout(SrcM.getDataLayout());
1809 if (SrcM.getDataLayout() != DstM.getDataLayout()) {
1810 emitWarning("Linking two modules of different data layouts: '" +
1811 SrcM.getModuleIdentifier() + "' is '" +
1812 SrcM.getDataLayoutStr() + "' whereas '" +
1813 DstM.getModuleIdentifier() + "' is '" +
1814 DstM.getDataLayoutStr() + "'\n");
1817 // Copy the target triple from the source to dest if the dest's is empty.
1818 if (DstM.getTargetTriple().empty() && !SrcM.getTargetTriple().empty())
1819 DstM.setTargetTriple(SrcM.getTargetTriple());
1821 Triple SrcTriple(SrcM.getTargetTriple()), DstTriple(DstM.getTargetTriple());
1823 if (!SrcM.getTargetTriple().empty() && !triplesMatch(SrcTriple, DstTriple))
1824 emitWarning("Linking two modules of different target triples: " +
1825 SrcM.getModuleIdentifier() + "' is '" + SrcM.getTargetTriple() +
1826 "' whereas '" + DstM.getModuleIdentifier() + "' is '" +
1827 DstM.getTargetTriple() + "'\n");
1829 DstM.setTargetTriple(mergeTriples(SrcTriple, DstTriple));
1831 // Append the module inline asm string.
1832 if (!SrcM.getModuleInlineAsm().empty()) {
1833 if (DstM.getModuleInlineAsm().empty())
1834 DstM.setModuleInlineAsm(SrcM.getModuleInlineAsm());
1836 DstM.setModuleInlineAsm(DstM.getModuleInlineAsm() + "\n" +
1837 SrcM.getModuleInlineAsm());
1840 // Loop over all of the linked values to compute type mappings.
1841 computeTypeMapping();
1843 ComdatsChosen.clear();
1844 for (const auto &SMEC : SrcM.getComdatSymbolTable()) {
1845 const Comdat &C = SMEC.getValue();
1846 if (ComdatsChosen.count(&C))
1848 Comdat::SelectionKind SK;
1850 if (getComdatResult(&C, SK, LinkFromSrc))
1852 ComdatsChosen[&C] = std::make_pair(SK, LinkFromSrc);
1855 // Upgrade mismatched global arrays.
1856 upgradeMismatchedGlobals();
1858 for (GlobalVariable &GV : SrcM.globals())
1859 if (const Comdat *SC = GV.getComdat())
1860 ComdatMembers[SC].push_back(&GV);
1862 for (Function &SF : SrcM)
1863 if (const Comdat *SC = SF.getComdat())
1864 ComdatMembers[SC].push_back(&SF);
1866 for (GlobalAlias &GA : SrcM.aliases())
1867 if (const Comdat *SC = GA.getComdat())
1868 ComdatMembers[SC].push_back(&GA);
1870 // Insert all of the globals in src into the DstM module... without linking
1871 // initializers (which could refer to functions not yet mapped over).
1872 for (GlobalVariable &GV : SrcM.globals())
1873 if (linkIfNeeded(GV))
1876 for (Function &SF : SrcM)
1877 if (linkIfNeeded(SF))
1880 for (GlobalAlias &GA : SrcM.aliases())
1881 if (linkIfNeeded(GA))
1884 for (const auto &Entry : DstM.getComdatSymbolTable()) {
1885 const Comdat &C = Entry.getValue();
1886 if (C.getSelectionKind() == Comdat::Any)
1888 const GlobalValue *GV = SrcM.getNamedValue(C.getName());
1890 MapValue(GV, ValueMap, RF_MoveDistinctMDs, &TypeMap, &ValMaterializer);
1893 // Note that we are done linking global value bodies. This prevents
1894 // metadata linking from creating new references.
1895 DoneLinkingBodies = true;
1897 // Remap all of the named MDNodes in Src into the DstM module. We do this
1898 // after linking GlobalValues so that MDNodes that reference GlobalValues
1899 // are properly remapped.
1902 // Merge the module flags into the DstM module.
1903 if (linkModuleFlagsMetadata())
1909 Linker::StructTypeKeyInfo::KeyTy::KeyTy(ArrayRef<Type *> E, bool P)
1910 : ETypes(E), IsPacked(P) {}
1912 Linker::StructTypeKeyInfo::KeyTy::KeyTy(const StructType *ST)
1913 : ETypes(ST->elements()), IsPacked(ST->isPacked()) {}
1915 bool Linker::StructTypeKeyInfo::KeyTy::operator==(const KeyTy &That) const {
1916 if (IsPacked != That.IsPacked)
1918 if (ETypes != That.ETypes)
1923 bool Linker::StructTypeKeyInfo::KeyTy::operator!=(const KeyTy &That) const {
1924 return !this->operator==(That);
1927 StructType *Linker::StructTypeKeyInfo::getEmptyKey() {
1928 return DenseMapInfo<StructType *>::getEmptyKey();
1931 StructType *Linker::StructTypeKeyInfo::getTombstoneKey() {
1932 return DenseMapInfo<StructType *>::getTombstoneKey();
1935 unsigned Linker::StructTypeKeyInfo::getHashValue(const KeyTy &Key) {
1936 return hash_combine(hash_combine_range(Key.ETypes.begin(), Key.ETypes.end()),
1940 unsigned Linker::StructTypeKeyInfo::getHashValue(const StructType *ST) {
1941 return getHashValue(KeyTy(ST));
1944 bool Linker::StructTypeKeyInfo::isEqual(const KeyTy &LHS,
1945 const StructType *RHS) {
1946 if (RHS == getEmptyKey() || RHS == getTombstoneKey())
1948 return LHS == KeyTy(RHS);
1951 bool Linker::StructTypeKeyInfo::isEqual(const StructType *LHS,
1952 const StructType *RHS) {
1953 if (RHS == getEmptyKey())
1954 return LHS == getEmptyKey();
1956 if (RHS == getTombstoneKey())
1957 return LHS == getTombstoneKey();
1959 return KeyTy(LHS) == KeyTy(RHS);
1962 void Linker::IdentifiedStructTypeSet::addNonOpaque(StructType *Ty) {
1963 assert(!Ty->isOpaque());
1964 NonOpaqueStructTypes.insert(Ty);
1967 void Linker::IdentifiedStructTypeSet::switchToNonOpaque(StructType *Ty) {
1968 assert(!Ty->isOpaque());
1969 NonOpaqueStructTypes.insert(Ty);
1970 bool Removed = OpaqueStructTypes.erase(Ty);
1975 void Linker::IdentifiedStructTypeSet::addOpaque(StructType *Ty) {
1976 assert(Ty->isOpaque());
1977 OpaqueStructTypes.insert(Ty);
1981 Linker::IdentifiedStructTypeSet::findNonOpaque(ArrayRef<Type *> ETypes,
1983 Linker::StructTypeKeyInfo::KeyTy Key(ETypes, IsPacked);
1984 auto I = NonOpaqueStructTypes.find_as(Key);
1985 if (I == NonOpaqueStructTypes.end())
1990 bool Linker::IdentifiedStructTypeSet::hasType(StructType *Ty) {
1992 return OpaqueStructTypes.count(Ty);
1993 auto I = NonOpaqueStructTypes.find(Ty);
1994 if (I == NonOpaqueStructTypes.end())
1999 Linker::Linker(Module &M, DiagnosticHandlerFunction DiagnosticHandler)
2000 : Composite(M), DiagnosticHandler(DiagnosticHandler) {
2001 TypeFinder StructTypes;
2002 StructTypes.run(M, true);
2003 for (StructType *Ty : StructTypes) {
2005 IdentifiedStructTypes.addOpaque(Ty);
2007 IdentifiedStructTypes.addNonOpaque(Ty);
2011 Linker::Linker(Module &M)
2012 : Linker(M, [this](const DiagnosticInfo &DI) {
2013 Composite.getContext().diagnose(DI);
2016 bool Linker::linkInModule(Module &Src, unsigned Flags,
2017 const FunctionInfoIndex *Index,
2018 DenseSet<const GlobalValue *> *FuncToImport) {
2019 ModuleLinker TheLinker(Composite, IdentifiedStructTypes, Src,
2020 DiagnosticHandler, Flags, Index, FuncToImport);
2021 bool RetCode = TheLinker.run();
2022 Composite.dropTriviallyDeadConstantArrays();
2026 //===----------------------------------------------------------------------===//
2027 // LinkModules entrypoint.
2028 //===----------------------------------------------------------------------===//
2030 /// This function links two modules together, with the resulting Dest module
2031 /// modified to be the composite of the two input modules. If an error occurs,
2032 /// true is returned and ErrorMsg (if not null) is set to indicate the problem.
2033 /// Upon failure, the Dest module could be in a modified state, and shouldn't be
2034 /// relied on to be consistent.
2035 bool Linker::linkModules(Module &Dest, Module &Src,
2036 DiagnosticHandlerFunction DiagnosticHandler,
2038 Linker L(Dest, DiagnosticHandler);
2039 return L.linkInModule(Src, Flags);
2042 bool Linker::linkModules(Module &Dest, Module &Src, unsigned Flags) {
2044 return L.linkInModule(Src, Flags);
2047 //===----------------------------------------------------------------------===//
2049 //===----------------------------------------------------------------------===//
2051 LLVMBool LLVMLinkModules(LLVMModuleRef Dest, LLVMModuleRef Src,
2052 LLVMLinkerMode Unused, char **OutMessages) {
2053 Module *D = unwrap(Dest);
2054 std::string Message;
2055 raw_string_ostream Stream(Message);
2056 DiagnosticPrinterRawOStream DP(Stream);
2058 LLVMBool Result = Linker::linkModules(
2059 *D, *unwrap(Src), [&](const DiagnosticInfo &DI) { DI.print(DP); });
2061 if (OutMessages && Result) {
2063 *OutMessages = strdup(Message.c_str());