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 SetVector<GlobalValue *> ValuesToLink;
397 DiagnosticHandlerFunction DiagnosticHandler;
399 /// For symbol clashes, prefer those from Src.
402 /// Function index passed into ModuleLinker for using in function
403 /// importing/exporting handling.
404 const FunctionInfoIndex *ImportIndex;
406 /// Function to import from source module, all other functions are
407 /// imported as declarations instead of definitions.
408 DenseSet<const GlobalValue *> *ImportFunction;
410 /// Set to true if the given FunctionInfoIndex contains any functions
411 /// from this source module, in which case we must conservatively assume
412 /// that any of its functions may be imported into another module
413 /// as part of a different backend compilation process.
414 bool HasExportedFunctions = false;
416 /// Set to true when all global value body linking is complete (including
417 /// lazy linking). Used to prevent metadata linking from creating new
419 bool DoneLinkingBodies = false;
421 bool HasError = false;
424 ModuleLinker(Module &DstM, Linker::IdentifiedStructTypeSet &Set, Module &SrcM,
425 DiagnosticHandlerFunction DiagnosticHandler, unsigned Flags,
426 const FunctionInfoIndex *Index = nullptr,
427 DenseSet<const GlobalValue *> *FunctionsToImport = nullptr)
428 : DstM(DstM), SrcM(SrcM), TypeMap(Set), ValMaterializer(this),
429 DiagnosticHandler(DiagnosticHandler), Flags(Flags), ImportIndex(Index),
430 ImportFunction(FunctionsToImport) {
431 assert((ImportIndex || !ImportFunction) &&
432 "Expect a FunctionInfoIndex when importing");
433 // If we have a FunctionInfoIndex but no function to import,
434 // then this is the primary module being compiled in a ThinLTO
435 // backend compilation, and we need to see if it has functions that
436 // may be exported to another backend compilation.
437 if (ImportIndex && !ImportFunction)
438 HasExportedFunctions = ImportIndex->hasExportedFunctions(SrcM);
442 Value *materializeDeclFor(Value *V);
443 void materializeInitFor(GlobalValue *New, GlobalValue *Old);
446 bool shouldOverrideFromSrc() { return Flags & Linker::OverrideFromSrc; }
447 bool shouldLinkOnlyNeeded() { return Flags & Linker::LinkOnlyNeeded; }
448 bool shouldInternalizeLinkedSymbols() {
449 return Flags & Linker::InternalizeLinkedSymbols;
452 /// Handles cloning of a global values from the source module into
453 /// the destination module, including setting the attributes and visibility.
454 GlobalValue *copyGlobalValueProto(const GlobalValue *SGV,
455 const GlobalValue *DGV, bool ForDefinition);
457 /// Check if we should promote the given local value to global scope.
458 bool doPromoteLocalToGlobal(const GlobalValue *SGV);
460 bool shouldLinkFromSource(bool &LinkFromSrc, const GlobalValue &Dest,
461 const GlobalValue &Src);
463 /// Helper method for setting a message and returning an error code.
464 bool emitError(const Twine &Message) {
465 DiagnosticHandler(LinkDiagnosticInfo(DS_Error, Message));
470 void emitWarning(const Twine &Message) {
471 DiagnosticHandler(LinkDiagnosticInfo(DS_Warning, Message));
474 bool getComdatLeader(Module &M, StringRef ComdatName,
475 const GlobalVariable *&GVar);
476 bool computeResultingSelectionKind(StringRef ComdatName,
477 Comdat::SelectionKind Src,
478 Comdat::SelectionKind Dst,
479 Comdat::SelectionKind &Result,
481 std::map<const Comdat *, std::pair<Comdat::SelectionKind, bool>>
483 bool getComdatResult(const Comdat *SrcC, Comdat::SelectionKind &SK,
485 // Keep track of the global value members of each comdat in source.
486 DenseMap<const Comdat *, std::vector<GlobalValue *>> ComdatMembers;
488 /// Given a global in the source module, return the global in the
489 /// destination module that is being linked to, if any.
490 GlobalValue *getLinkedToGlobal(const GlobalValue *SrcGV) {
491 // If the source has no name it can't link. If it has local linkage,
492 // there is no name match-up going on.
493 if (!SrcGV->hasName() || GlobalValue::isLocalLinkage(getLinkage(SrcGV)))
496 // Otherwise see if we have a match in the destination module's symtab.
497 GlobalValue *DGV = DstM.getNamedValue(getName(SrcGV));
501 // If we found a global with the same name in the dest module, but it has
502 // internal linkage, we are really not doing any linkage here.
503 if (DGV->hasLocalLinkage())
506 // Otherwise, we do in fact link to the destination global.
510 void computeTypeMapping();
512 void upgradeMismatchedGlobalArray(StringRef Name);
513 void upgradeMismatchedGlobals();
515 bool linkIfNeeded(GlobalValue &GV);
516 Constant *linkAppendingVarProto(GlobalVariable *DstGV,
517 const GlobalVariable *SrcGV);
519 Constant *linkGlobalValueProto(GlobalValue *GV);
520 bool linkModuleFlagsMetadata();
522 void linkGlobalInit(GlobalVariable &Dst, GlobalVariable &Src);
523 bool linkFunctionBody(Function &Dst, Function &Src);
524 void linkAliasBody(GlobalAlias &Dst, GlobalAlias &Src);
525 bool linkGlobalValueBody(GlobalValue &Dst, GlobalValue &Src);
527 /// Functions that take care of cloning a specific global value type
528 /// into the destination module.
529 GlobalVariable *copyGlobalVariableProto(const GlobalVariable *SGVar);
530 Function *copyFunctionProto(const Function *SF);
531 GlobalValue *copyGlobalAliasProto(const GlobalAlias *SGA);
533 /// Helper methods to check if we are importing from or potentially
534 /// exporting from the current source module.
535 bool isPerformingImport() { return ImportFunction != nullptr; }
536 bool isModuleExporting() { return HasExportedFunctions; }
538 /// If we are importing from the source module, checks if we should
539 /// import SGV as a definition, otherwise import as a declaration.
540 bool doImportAsDefinition(const GlobalValue *SGV);
542 /// Get the name for SGV that should be used in the linked destination
543 /// module. Specifically, this handles the case where we need to rename
544 /// a local that is being promoted to global scope.
545 std::string getName(const GlobalValue *SGV);
547 /// Get the new linkage for SGV that should be used in the linked destination
548 /// module. Specifically, for ThinLTO importing or exporting it may need
550 GlobalValue::LinkageTypes getLinkage(const GlobalValue *SGV);
552 /// Copies the necessary global value attributes and name from the source
553 /// to the newly cloned global value.
554 void copyGVAttributes(GlobalValue *NewGV, const GlobalValue *SrcGV);
556 /// Updates the visibility for the new global cloned from the source
557 /// and, if applicable, linked with an existing destination global.
558 /// Handles visibility change required for promoted locals.
559 void setVisibility(GlobalValue *NewGV, const GlobalValue *SGV,
560 const GlobalValue *DGV = nullptr);
562 void linkNamedMDNodes();
566 /// The LLVM SymbolTable class autorenames globals that conflict in the symbol
567 /// table. This is good for all clients except for us. Go through the trouble
568 /// to force this back.
569 static void forceRenaming(GlobalValue *GV, StringRef Name) {
570 // If the global doesn't force its name or if it already has the right name,
571 // there is nothing for us to do.
572 // Note that any required local to global promotion should already be done,
573 // so promoted locals will not skip this handling as their linkage is no
575 if (GV->hasLocalLinkage() || GV->getName() == Name)
578 Module *M = GV->getParent();
580 // If there is a conflict, rename the conflict.
581 if (GlobalValue *ConflictGV = M->getNamedValue(Name)) {
582 GV->takeName(ConflictGV);
583 ConflictGV->setName(Name); // This will cause ConflictGV to get renamed
584 assert(ConflictGV->getName() != Name && "forceRenaming didn't work");
586 GV->setName(Name); // Force the name back
590 /// copy additional attributes (those not needed to construct a GlobalValue)
591 /// from the SrcGV to the DestGV.
592 void ModuleLinker::copyGVAttributes(GlobalValue *NewGV,
593 const GlobalValue *SrcGV) {
594 NewGV->copyAttributesFrom(SrcGV);
595 forceRenaming(NewGV, getName(SrcGV));
598 bool ModuleLinker::doImportAsDefinition(const GlobalValue *SGV) {
599 if (!isPerformingImport())
601 auto *GA = dyn_cast<GlobalAlias>(SGV);
603 if (GA->hasWeakAnyLinkage())
605 const GlobalObject *GO = GA->getBaseObject();
606 if (!GO->hasLinkOnceODRLinkage())
608 return doImportAsDefinition(GO);
610 // Always import GlobalVariable definitions, except for the special
611 // case of WeakAny which are imported as ExternalWeak declarations
612 // (see comments in ModuleLinker::getLinkage). The linkage changes
613 // described in ModuleLinker::getLinkage ensure the correct behavior (e.g.
614 // global variables with external linkage are transformed to
615 // available_externally definitions, which are ultimately turned into
616 // declarations after the EliminateAvailableExternally pass).
617 if (isa<GlobalVariable>(SGV) && !SGV->isDeclaration() &&
618 !SGV->hasWeakAnyLinkage())
620 // Only import the function requested for importing.
621 auto *SF = dyn_cast<Function>(SGV);
622 if (SF && ImportFunction->count(SF))
628 bool ModuleLinker::doPromoteLocalToGlobal(const GlobalValue *SGV) {
629 assert(SGV->hasLocalLinkage());
630 // Both the imported references and the original local variable must
632 if (!isPerformingImport() && !isModuleExporting())
635 // Local const variables never need to be promoted unless they are address
636 // taken. The imported uses can simply use the clone created in this module.
637 // For now we are conservative in determining which variables are not
638 // address taken by checking the unnamed addr flag. To be more aggressive,
639 // the address taken information must be checked earlier during parsing
640 // of the module and recorded in the function index for use when importing
642 auto *GVar = dyn_cast<GlobalVariable>(SGV);
643 if (GVar && GVar->isConstant() && GVar->hasUnnamedAddr())
646 // Eventually we only need to promote functions in the exporting module that
647 // are referenced by a potentially exported function (i.e. one that is in the
652 std::string ModuleLinker::getName(const GlobalValue *SGV) {
653 // For locals that must be promoted to global scope, ensure that
654 // the promoted name uniquely identifies the copy in the original module,
655 // using the ID assigned during combined index creation. When importing,
656 // we rename all locals (not just those that are promoted) in order to
657 // avoid naming conflicts between locals imported from different modules.
658 if (SGV->hasLocalLinkage() &&
659 (doPromoteLocalToGlobal(SGV) || isPerformingImport()))
660 return FunctionInfoIndex::getGlobalNameForLocal(
662 ImportIndex->getModuleId(SGV->getParent()->getModuleIdentifier()));
663 return SGV->getName();
666 GlobalValue::LinkageTypes ModuleLinker::getLinkage(const GlobalValue *SGV) {
667 // Any local variable that is referenced by an exported function needs
668 // to be promoted to global scope. Since we don't currently know which
669 // functions reference which local variables/functions, we must treat
670 // all as potentially exported if this module is exporting anything.
671 if (isModuleExporting()) {
672 if (SGV->hasLocalLinkage() && doPromoteLocalToGlobal(SGV))
673 return GlobalValue::ExternalLinkage;
674 return SGV->getLinkage();
677 // Otherwise, if we aren't importing, no linkage change is needed.
678 if (!isPerformingImport())
679 return SGV->getLinkage();
681 switch (SGV->getLinkage()) {
682 case GlobalValue::ExternalLinkage:
683 // External defnitions are converted to available_externally
684 // definitions upon import, so that they are available for inlining
685 // and/or optimization, but are turned into declarations later
686 // during the EliminateAvailableExternally pass.
687 if (doImportAsDefinition(SGV) && !dyn_cast<GlobalAlias>(SGV))
688 return GlobalValue::AvailableExternallyLinkage;
689 // An imported external declaration stays external.
690 return SGV->getLinkage();
692 case GlobalValue::AvailableExternallyLinkage:
693 // An imported available_externally definition converts
694 // to external if imported as a declaration.
695 if (!doImportAsDefinition(SGV))
696 return GlobalValue::ExternalLinkage;
697 // An imported available_externally declaration stays that way.
698 return SGV->getLinkage();
700 case GlobalValue::LinkOnceAnyLinkage:
701 case GlobalValue::LinkOnceODRLinkage:
702 // These both stay the same when importing the definition.
703 // The ThinLTO pass will eventually force-import their definitions.
704 return SGV->getLinkage();
706 case GlobalValue::WeakAnyLinkage:
707 // Can't import weak_any definitions correctly, or we might change the
708 // program semantics, since the linker will pick the first weak_any
709 // definition and importing would change the order they are seen by the
710 // linker. The module linking caller needs to enforce this.
711 assert(!doImportAsDefinition(SGV));
712 // If imported as a declaration, it becomes external_weak.
713 return GlobalValue::ExternalWeakLinkage;
715 case GlobalValue::WeakODRLinkage:
716 // For weak_odr linkage, there is a guarantee that all copies will be
717 // equivalent, so the issue described above for weak_any does not exist,
718 // and the definition can be imported. It can be treated similarly
719 // to an imported externally visible global value.
720 if (doImportAsDefinition(SGV) && !dyn_cast<GlobalAlias>(SGV))
721 return GlobalValue::AvailableExternallyLinkage;
723 return GlobalValue::ExternalLinkage;
725 case GlobalValue::AppendingLinkage:
726 // It would be incorrect to import an appending linkage variable,
727 // since it would cause global constructors/destructors to be
728 // executed multiple times. This should have already been handled
729 // by linkGlobalValueProto.
730 llvm_unreachable("Cannot import appending linkage variable");
732 case GlobalValue::InternalLinkage:
733 case GlobalValue::PrivateLinkage:
734 // If we are promoting the local to global scope, it is handled
735 // similarly to a normal externally visible global.
736 if (doPromoteLocalToGlobal(SGV)) {
737 if (doImportAsDefinition(SGV) && !dyn_cast<GlobalAlias>(SGV))
738 return GlobalValue::AvailableExternallyLinkage;
740 return GlobalValue::ExternalLinkage;
742 // A non-promoted imported local definition stays local.
743 // The ThinLTO pass will eventually force-import their definitions.
744 return SGV->getLinkage();
746 case GlobalValue::ExternalWeakLinkage:
747 // External weak doesn't apply to definitions, must be a declaration.
748 assert(!doImportAsDefinition(SGV));
749 // Linkage stays external_weak.
750 return SGV->getLinkage();
752 case GlobalValue::CommonLinkage:
753 // Linkage stays common on definitions.
754 // The ThinLTO pass will eventually force-import their definitions.
755 return SGV->getLinkage();
758 llvm_unreachable("unknown linkage type");
761 /// Loop through the global variables in the src module and merge them into the
764 ModuleLinker::copyGlobalVariableProto(const GlobalVariable *SGVar) {
765 // No linking to be performed or linking from the source: simply create an
766 // identical version of the symbol over in the dest module... the
767 // initializer will be filled in later by LinkGlobalInits.
768 GlobalVariable *NewDGV =
769 new GlobalVariable(DstM, TypeMap.get(SGVar->getType()->getElementType()),
770 SGVar->isConstant(), GlobalValue::ExternalLinkage,
771 /*init*/ nullptr, getName(SGVar),
772 /*insertbefore*/ nullptr, SGVar->getThreadLocalMode(),
773 SGVar->getType()->getAddressSpace());
778 /// Link the function in the source module into the destination module if
779 /// needed, setting up mapping information.
780 Function *ModuleLinker::copyFunctionProto(const Function *SF) {
781 // If there is no linkage to be performed or we are linking from the source,
783 return Function::Create(TypeMap.get(SF->getFunctionType()),
784 GlobalValue::ExternalLinkage, getName(SF), &DstM);
787 /// Set up prototypes for any aliases that come over from the source module.
788 GlobalValue *ModuleLinker::copyGlobalAliasProto(const GlobalAlias *SGA) {
789 // If there is no linkage to be performed or we're linking from the source,
791 auto *Ty = TypeMap.get(SGA->getValueType());
792 return GlobalAlias::create(Ty, SGA->getType()->getPointerAddressSpace(),
793 GlobalValue::ExternalLinkage, getName(SGA), &DstM);
796 static GlobalValue::VisibilityTypes
797 getMinVisibility(GlobalValue::VisibilityTypes A,
798 GlobalValue::VisibilityTypes B) {
799 if (A == GlobalValue::HiddenVisibility || B == GlobalValue::HiddenVisibility)
800 return GlobalValue::HiddenVisibility;
801 if (A == GlobalValue::ProtectedVisibility ||
802 B == GlobalValue::ProtectedVisibility)
803 return GlobalValue::ProtectedVisibility;
804 return GlobalValue::DefaultVisibility;
807 void ModuleLinker::setVisibility(GlobalValue *NewGV, const GlobalValue *SGV,
808 const GlobalValue *DGV) {
809 GlobalValue::VisibilityTypes Visibility = SGV->getVisibility();
811 Visibility = getMinVisibility(DGV->getVisibility(), Visibility);
812 // For promoted locals, mark them hidden so that they can later be
813 // stripped from the symbol table to reduce bloat.
814 if (SGV->hasLocalLinkage() && doPromoteLocalToGlobal(SGV))
815 Visibility = GlobalValue::HiddenVisibility;
816 NewGV->setVisibility(Visibility);
819 GlobalValue *ModuleLinker::copyGlobalValueProto(const GlobalValue *SGV,
820 const GlobalValue *DGV,
821 bool ForDefinition) {
823 if (auto *SGVar = dyn_cast<GlobalVariable>(SGV)) {
824 NewGV = copyGlobalVariableProto(SGVar);
825 } else if (auto *SF = dyn_cast<Function>(SGV)) {
826 NewGV = copyFunctionProto(SF);
829 NewGV = copyGlobalAliasProto(cast<GlobalAlias>(SGV));
831 NewGV = new GlobalVariable(
832 DstM, TypeMap.get(SGV->getType()->getElementType()),
833 /*isConstant*/ false, GlobalValue::ExternalLinkage,
834 /*init*/ nullptr, getName(SGV),
835 /*insertbefore*/ nullptr, SGV->getThreadLocalMode(),
836 SGV->getType()->getAddressSpace());
840 NewGV->setLinkage(getLinkage(SGV));
841 else if (SGV->hasAvailableExternallyLinkage() || SGV->hasWeakLinkage() ||
842 SGV->hasLinkOnceLinkage())
843 NewGV->setLinkage(GlobalValue::ExternalWeakLinkage);
845 copyGVAttributes(NewGV, SGV);
846 setVisibility(NewGV, SGV, DGV);
850 Value *ValueMaterializerTy::materializeDeclFor(Value *V) {
851 return ModLinker->materializeDeclFor(V);
854 Value *ModuleLinker::materializeDeclFor(Value *V) {
855 auto *SGV = dyn_cast<GlobalValue>(V);
859 return linkGlobalValueProto(SGV);
862 void ValueMaterializerTy::materializeInitFor(GlobalValue *New,
864 return ModLinker->materializeInitFor(New, Old);
867 static bool shouldLazyLink(const GlobalValue &GV) {
868 return GV.hasLocalLinkage() || GV.hasLinkOnceLinkage() ||
869 GV.hasAvailableExternallyLinkage();
872 void ModuleLinker::materializeInitFor(GlobalValue *New, GlobalValue *Old) {
873 if (auto *F = dyn_cast<Function>(New)) {
874 if (!F->isDeclaration())
876 } else if (auto *V = dyn_cast<GlobalVariable>(New)) {
877 if (V->hasInitializer())
880 auto *A = cast<GlobalAlias>(New);
885 if (Old->isDeclaration())
888 if (isPerformingImport() && !doImportAsDefinition(Old))
891 if (!ValuesToLink.count(Old) && !shouldLazyLink(*Old))
894 linkGlobalValueBody(*New, *Old);
897 bool ModuleLinker::getComdatLeader(Module &M, StringRef ComdatName,
898 const GlobalVariable *&GVar) {
899 const GlobalValue *GVal = M.getNamedValue(ComdatName);
900 if (const auto *GA = dyn_cast_or_null<GlobalAlias>(GVal)) {
901 GVal = GA->getBaseObject();
903 // We cannot resolve the size of the aliasee yet.
904 return emitError("Linking COMDATs named '" + ComdatName +
905 "': COMDAT key involves incomputable alias size.");
908 GVar = dyn_cast_or_null<GlobalVariable>(GVal);
911 "Linking COMDATs named '" + ComdatName +
912 "': GlobalVariable required for data dependent selection!");
917 bool ModuleLinker::computeResultingSelectionKind(StringRef ComdatName,
918 Comdat::SelectionKind Src,
919 Comdat::SelectionKind Dst,
920 Comdat::SelectionKind &Result,
922 // The ability to mix Comdat::SelectionKind::Any with
923 // Comdat::SelectionKind::Largest is a behavior that comes from COFF.
924 bool DstAnyOrLargest = Dst == Comdat::SelectionKind::Any ||
925 Dst == Comdat::SelectionKind::Largest;
926 bool SrcAnyOrLargest = Src == Comdat::SelectionKind::Any ||
927 Src == Comdat::SelectionKind::Largest;
928 if (DstAnyOrLargest && SrcAnyOrLargest) {
929 if (Dst == Comdat::SelectionKind::Largest ||
930 Src == Comdat::SelectionKind::Largest)
931 Result = Comdat::SelectionKind::Largest;
933 Result = Comdat::SelectionKind::Any;
934 } else if (Src == Dst) {
937 return emitError("Linking COMDATs named '" + ComdatName +
938 "': invalid selection kinds!");
942 case Comdat::SelectionKind::Any:
946 case Comdat::SelectionKind::NoDuplicates:
947 return emitError("Linking COMDATs named '" + ComdatName +
948 "': noduplicates has been violated!");
949 case Comdat::SelectionKind::ExactMatch:
950 case Comdat::SelectionKind::Largest:
951 case Comdat::SelectionKind::SameSize: {
952 const GlobalVariable *DstGV;
953 const GlobalVariable *SrcGV;
954 if (getComdatLeader(DstM, ComdatName, DstGV) ||
955 getComdatLeader(SrcM, ComdatName, SrcGV))
958 const DataLayout &DstDL = DstM.getDataLayout();
959 const DataLayout &SrcDL = SrcM.getDataLayout();
961 DstDL.getTypeAllocSize(DstGV->getType()->getPointerElementType());
963 SrcDL.getTypeAllocSize(SrcGV->getType()->getPointerElementType());
964 if (Result == Comdat::SelectionKind::ExactMatch) {
965 if (SrcGV->getInitializer() != DstGV->getInitializer())
966 return emitError("Linking COMDATs named '" + ComdatName +
967 "': ExactMatch violated!");
969 } else if (Result == Comdat::SelectionKind::Largest) {
970 LinkFromSrc = SrcSize > DstSize;
971 } else if (Result == Comdat::SelectionKind::SameSize) {
972 if (SrcSize != DstSize)
973 return emitError("Linking COMDATs named '" + ComdatName +
974 "': SameSize violated!");
977 llvm_unreachable("unknown selection kind");
986 bool ModuleLinker::getComdatResult(const Comdat *SrcC,
987 Comdat::SelectionKind &Result,
989 Comdat::SelectionKind SSK = SrcC->getSelectionKind();
990 StringRef ComdatName = SrcC->getName();
991 Module::ComdatSymTabType &ComdatSymTab = DstM.getComdatSymbolTable();
992 Module::ComdatSymTabType::iterator DstCI = ComdatSymTab.find(ComdatName);
994 if (DstCI == ComdatSymTab.end()) {
995 // Use the comdat if it is only available in one of the modules.
1001 const Comdat *DstC = &DstCI->second;
1002 Comdat::SelectionKind DSK = DstC->getSelectionKind();
1003 return computeResultingSelectionKind(ComdatName, SSK, DSK, Result,
1007 bool ModuleLinker::shouldLinkFromSource(bool &LinkFromSrc,
1008 const GlobalValue &Dest,
1009 const GlobalValue &Src) {
1010 // Should we unconditionally use the Src?
1011 if (shouldOverrideFromSrc()) {
1016 // We always have to add Src if it has appending linkage.
1017 if (Src.hasAppendingLinkage()) {
1018 // Caller should have already determined that we can't link from source
1019 // when importing (see comments in linkGlobalValueProto).
1020 assert(!isPerformingImport());
1025 bool SrcIsDeclaration = Src.isDeclarationForLinker();
1026 bool DestIsDeclaration = Dest.isDeclarationForLinker();
1028 if (isPerformingImport()) {
1029 if (isa<Function>(&Src)) {
1030 // For functions, LinkFromSrc iff this is the function requested
1031 // for importing. For variables, decide below normally.
1032 LinkFromSrc = ImportFunction->count(&Src);
1036 // Check if this is an alias with an already existing definition
1037 // in Dest, which must have come from a prior importing pass from
1038 // the same Src module. Unlike imported function and variable
1039 // definitions, which are imported as available_externally and are
1040 // not definitions for the linker, that is not a valid linkage for
1041 // imported aliases which must be definitions. Simply use the existing
1043 if (isa<GlobalAlias>(&Src) && !DestIsDeclaration) {
1044 assert(isa<GlobalAlias>(&Dest));
1045 LinkFromSrc = false;
1050 if (SrcIsDeclaration) {
1051 // If Src is external or if both Src & Dest are external.. Just link the
1052 // external globals, we aren't adding anything.
1053 if (Src.hasDLLImportStorageClass()) {
1054 // If one of GVs is marked as DLLImport, result should be dllimport'ed.
1055 LinkFromSrc = DestIsDeclaration;
1058 // If the Dest is weak, use the source linkage.
1059 LinkFromSrc = Dest.hasExternalWeakLinkage();
1063 if (DestIsDeclaration) {
1064 // If Dest is external but Src is not:
1069 if (Src.hasCommonLinkage()) {
1070 if (Dest.hasLinkOnceLinkage() || Dest.hasWeakLinkage()) {
1075 if (!Dest.hasCommonLinkage()) {
1076 LinkFromSrc = false;
1080 const DataLayout &DL = Dest.getParent()->getDataLayout();
1081 uint64_t DestSize = DL.getTypeAllocSize(Dest.getType()->getElementType());
1082 uint64_t SrcSize = DL.getTypeAllocSize(Src.getType()->getElementType());
1083 LinkFromSrc = SrcSize > DestSize;
1087 if (Src.isWeakForLinker()) {
1088 assert(!Dest.hasExternalWeakLinkage());
1089 assert(!Dest.hasAvailableExternallyLinkage());
1091 if (Dest.hasLinkOnceLinkage() && Src.hasWeakLinkage()) {
1096 LinkFromSrc = false;
1100 if (Dest.isWeakForLinker()) {
1101 assert(Src.hasExternalLinkage());
1106 assert(!Src.hasExternalWeakLinkage());
1107 assert(!Dest.hasExternalWeakLinkage());
1108 assert(Dest.hasExternalLinkage() && Src.hasExternalLinkage() &&
1109 "Unexpected linkage type!");
1110 return emitError("Linking globals named '" + Src.getName() +
1111 "': symbol multiply defined!");
1114 /// Loop over all of the linked values to compute type mappings. For example,
1115 /// if we link "extern Foo *x" and "Foo *x = NULL", then we have two struct
1116 /// types 'Foo' but one got renamed when the module was loaded into the same
1118 void ModuleLinker::computeTypeMapping() {
1119 for (GlobalValue &SGV : SrcM.globals()) {
1120 GlobalValue *DGV = getLinkedToGlobal(&SGV);
1124 if (!DGV->hasAppendingLinkage() || !SGV.hasAppendingLinkage()) {
1125 TypeMap.addTypeMapping(DGV->getType(), SGV.getType());
1129 // Unify the element type of appending arrays.
1130 ArrayType *DAT = cast<ArrayType>(DGV->getType()->getElementType());
1131 ArrayType *SAT = cast<ArrayType>(SGV.getType()->getElementType());
1132 TypeMap.addTypeMapping(DAT->getElementType(), SAT->getElementType());
1135 for (GlobalValue &SGV : SrcM) {
1136 if (GlobalValue *DGV = getLinkedToGlobal(&SGV))
1137 TypeMap.addTypeMapping(DGV->getType(), SGV.getType());
1140 for (GlobalValue &SGV : SrcM.aliases()) {
1141 if (GlobalValue *DGV = getLinkedToGlobal(&SGV))
1142 TypeMap.addTypeMapping(DGV->getType(), SGV.getType());
1145 // Incorporate types by name, scanning all the types in the source module.
1146 // At this point, the destination module may have a type "%foo = { i32 }" for
1147 // example. When the source module got loaded into the same LLVMContext, if
1148 // it had the same type, it would have been renamed to "%foo.42 = { i32 }".
1149 std::vector<StructType *> Types = SrcM.getIdentifiedStructTypes();
1150 for (StructType *ST : Types) {
1154 // Check to see if there is a dot in the name followed by a digit.
1155 size_t DotPos = ST->getName().rfind('.');
1156 if (DotPos == 0 || DotPos == StringRef::npos ||
1157 ST->getName().back() == '.' ||
1158 !isdigit(static_cast<unsigned char>(ST->getName()[DotPos + 1])))
1161 // Check to see if the destination module has a struct with the prefix name.
1162 StructType *DST = DstM.getTypeByName(ST->getName().substr(0, DotPos));
1166 // Don't use it if this actually came from the source module. They're in
1167 // the same LLVMContext after all. Also don't use it unless the type is
1168 // actually used in the destination module. This can happen in situations
1171 // Module A Module B
1172 // -------- --------
1173 // %Z = type { %A } %B = type { %C.1 }
1174 // %A = type { %B.1, [7 x i8] } %C.1 = type { i8* }
1175 // %B.1 = type { %C } %A.2 = type { %B.3, [5 x i8] }
1176 // %C = type { i8* } %B.3 = type { %C.1 }
1178 // When we link Module B with Module A, the '%B' in Module B is
1179 // used. However, that would then use '%C.1'. But when we process '%C.1',
1180 // we prefer to take the '%C' version. So we are then left with both
1181 // '%C.1' and '%C' being used for the same types. This leads to some
1182 // variables using one type and some using the other.
1183 if (TypeMap.DstStructTypesSet.hasType(DST))
1184 TypeMap.addTypeMapping(DST, ST);
1187 // Now that we have discovered all of the type equivalences, get a body for
1188 // any 'opaque' types in the dest module that are now resolved.
1189 TypeMap.linkDefinedTypeBodies();
1192 static void upgradeGlobalArray(GlobalVariable *GV) {
1193 ArrayType *ATy = cast<ArrayType>(GV->getType()->getElementType());
1194 StructType *OldTy = cast<StructType>(ATy->getElementType());
1195 assert(OldTy->getNumElements() == 2 && "Expected to upgrade from 2 elements");
1197 // Get the upgraded 3 element type.
1198 PointerType *VoidPtrTy = Type::getInt8Ty(GV->getContext())->getPointerTo();
1199 Type *Tys[3] = {OldTy->getElementType(0), OldTy->getElementType(1),
1201 StructType *NewTy = StructType::get(GV->getContext(), Tys, false);
1203 // Build new constants with a null third field filled in.
1204 Constant *OldInitC = GV->getInitializer();
1205 ConstantArray *OldInit = dyn_cast<ConstantArray>(OldInitC);
1206 if (!OldInit && !isa<ConstantAggregateZero>(OldInitC))
1207 // Invalid initializer; give up.
1209 std::vector<Constant *> Initializers;
1210 if (OldInit && OldInit->getNumOperands()) {
1211 Value *Null = Constant::getNullValue(VoidPtrTy);
1212 for (Use &U : OldInit->operands()) {
1213 ConstantStruct *Init = cast<ConstantStruct>(U.get());
1214 Initializers.push_back(ConstantStruct::get(
1215 NewTy, Init->getOperand(0), Init->getOperand(1), Null, nullptr));
1218 assert(Initializers.size() == ATy->getNumElements() &&
1219 "Failed to copy all array elements");
1221 // Replace the old GV with a new one.
1222 ATy = ArrayType::get(NewTy, Initializers.size());
1223 Constant *NewInit = ConstantArray::get(ATy, Initializers);
1224 GlobalVariable *NewGV = new GlobalVariable(
1225 *GV->getParent(), ATy, GV->isConstant(), GV->getLinkage(), NewInit, "",
1226 GV, GV->getThreadLocalMode(), GV->getType()->getAddressSpace(),
1227 GV->isExternallyInitialized());
1228 NewGV->copyAttributesFrom(GV);
1229 NewGV->takeName(GV);
1230 assert(GV->use_empty() && "program cannot use initializer list");
1231 GV->eraseFromParent();
1234 void ModuleLinker::upgradeMismatchedGlobalArray(StringRef Name) {
1235 // Look for the global arrays.
1236 auto *DstGV = dyn_cast_or_null<GlobalVariable>(DstM.getNamedValue(Name));
1239 auto *SrcGV = dyn_cast_or_null<GlobalVariable>(SrcM.getNamedValue(Name));
1243 // Check if the types already match.
1244 auto *DstTy = cast<ArrayType>(DstGV->getType()->getElementType());
1246 cast<ArrayType>(TypeMap.get(SrcGV->getType()->getElementType()));
1250 // Grab the element types. We can only upgrade an array of a two-field
1251 // struct. Only bother if the other one has three-fields.
1252 auto *DstEltTy = cast<StructType>(DstTy->getElementType());
1253 auto *SrcEltTy = cast<StructType>(SrcTy->getElementType());
1254 if (DstEltTy->getNumElements() == 2 && SrcEltTy->getNumElements() == 3) {
1255 upgradeGlobalArray(DstGV);
1258 if (DstEltTy->getNumElements() == 3 && SrcEltTy->getNumElements() == 2)
1259 upgradeGlobalArray(SrcGV);
1261 // We can't upgrade any other differences.
1264 void ModuleLinker::upgradeMismatchedGlobals() {
1265 upgradeMismatchedGlobalArray("llvm.global_ctors");
1266 upgradeMismatchedGlobalArray("llvm.global_dtors");
1269 static void getArrayElements(const Constant *C,
1270 SmallVectorImpl<Constant *> &Dest) {
1271 unsigned NumElements = cast<ArrayType>(C->getType())->getNumElements();
1273 for (unsigned i = 0; i != NumElements; ++i)
1274 Dest.push_back(C->getAggregateElement(i));
1277 /// If there were any appending global variables, link them together now.
1278 /// Return true on error.
1279 Constant *ModuleLinker::linkAppendingVarProto(GlobalVariable *DstGV,
1280 const GlobalVariable *SrcGV) {
1282 cast<ArrayType>(TypeMap.get(SrcGV->getType()->getElementType()));
1283 Type *EltTy = SrcTy->getElementType();
1286 ArrayType *DstTy = cast<ArrayType>(DstGV->getType()->getElementType());
1288 if (!SrcGV->hasAppendingLinkage() || !DstGV->hasAppendingLinkage()) {
1290 "Linking globals named '" + SrcGV->getName() +
1291 "': can only link appending global with another appending global!");
1295 // Check to see that they two arrays agree on type.
1296 if (EltTy != DstTy->getElementType()) {
1297 emitError("Appending variables with different element types!");
1300 if (DstGV->isConstant() != SrcGV->isConstant()) {
1301 emitError("Appending variables linked with different const'ness!");
1305 if (DstGV->getAlignment() != SrcGV->getAlignment()) {
1307 "Appending variables with different alignment need to be linked!");
1311 if (DstGV->getVisibility() != SrcGV->getVisibility()) {
1313 "Appending variables with different visibility need to be linked!");
1317 if (DstGV->hasUnnamedAddr() != SrcGV->hasUnnamedAddr()) {
1319 "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!");
1330 SmallVector<Constant *, 16> DstElements;
1332 getArrayElements(DstGV->getInitializer(), DstElements);
1334 SmallVector<Constant *, 16> SrcElements;
1335 getArrayElements(SrcGV->getInitializer(), SrcElements);
1337 StringRef Name = SrcGV->getName();
1338 bool IsNewStructor =
1339 (Name == "llvm.global_ctors" || Name == "llvm.global_dtors") &&
1340 cast<StructType>(EltTy)->getNumElements() == 3;
1343 std::remove_if(SrcElements.begin(), SrcElements.end(),
1344 [this](Constant *E) {
1345 auto *Key = dyn_cast<GlobalValue>(
1346 E->getAggregateElement(2)->stripPointerCasts());
1347 return Key && !ValuesToLink.count(Key) &&
1348 !shouldLazyLink(*Key);
1351 uint64_t NewSize = DstElements.size() + SrcElements.size();
1352 ArrayType *NewType = ArrayType::get(EltTy, NewSize);
1354 // Create the new global variable.
1355 GlobalVariable *NG = new GlobalVariable(
1356 DstM, NewType, SrcGV->isConstant(), SrcGV->getLinkage(),
1357 /*init*/ nullptr, /*name*/ "", DstGV, SrcGV->getThreadLocalMode(),
1358 SrcGV->getType()->getAddressSpace());
1360 // Propagate alignment, visibility and section info.
1361 copyGVAttributes(NG, SrcGV);
1363 Constant *Ret = ConstantExpr::getBitCast(NG, TypeMap.get(SrcGV->getType()));
1366 ValueMap[SrcGV] = Ret;
1368 for (auto *V : SrcElements) {
1369 DstElements.push_back(
1370 MapValue(V, ValueMap, RF_MoveDistinctMDs, &TypeMap, &ValMaterializer));
1373 NG->setInitializer(ConstantArray::get(NewType, DstElements));
1375 // Replace any uses of the two global variables with uses of the new
1378 DstGV->replaceAllUsesWith(ConstantExpr::getBitCast(NG, DstGV->getType()));
1379 DstGV->eraseFromParent();
1385 Constant *ModuleLinker::linkGlobalValueProto(GlobalValue *SGV) {
1386 GlobalValue *DGV = getLinkedToGlobal(SGV);
1388 // Handle the ultra special appending linkage case first.
1389 assert(!DGV || SGV->hasAppendingLinkage() == DGV->hasAppendingLinkage());
1390 if (SGV->hasAppendingLinkage())
1391 return linkAppendingVarProto(cast_or_null<GlobalVariable>(DGV),
1392 cast<GlobalVariable>(SGV));
1394 bool LinkFromSrc = true;
1395 Comdat *C = nullptr;
1396 bool HasUnnamedAddr = SGV->hasUnnamedAddr();
1398 if (isPerformingImport() && !doImportAsDefinition(SGV)) {
1399 LinkFromSrc = false;
1400 } else if (const Comdat *SC = SGV->getComdat()) {
1401 Comdat::SelectionKind SK;
1402 std::tie(SK, LinkFromSrc) = ComdatsChosen[SC];
1403 C = DstM.getOrInsertComdat(SC->getName());
1404 C->setSelectionKind(SK);
1405 if (SGV->hasLocalLinkage())
1408 if (shouldLinkFromSource(LinkFromSrc, *DGV, *SGV))
1413 HasUnnamedAddr = HasUnnamedAddr && DGV->hasUnnamedAddr();
1416 if (!LinkFromSrc && DGV) {
1418 // When linking from source we setVisibility from copyGlobalValueProto.
1419 setVisibility(NewGV, SGV, DGV);
1421 // If we are done linking global value bodies (i.e. we are performing
1422 // metadata linking), don't link in the global value due to this
1423 // reference, simply map it to null.
1424 if (DoneLinkingBodies)
1427 NewGV = copyGlobalValueProto(SGV, DGV, LinkFromSrc);
1430 NewGV->setUnnamedAddr(HasUnnamedAddr);
1432 if (auto *NewGO = dyn_cast<GlobalObject>(NewGV)) {
1433 if (C && LinkFromSrc)
1434 NewGO->setComdat(C);
1436 if (DGV && DGV->hasCommonLinkage() && SGV->hasCommonLinkage())
1437 NewGO->setAlignment(std::max(DGV->getAlignment(), SGV->getAlignment()));
1440 if (auto *NewGVar = dyn_cast<GlobalVariable>(NewGV)) {
1441 auto *DGVar = dyn_cast_or_null<GlobalVariable>(DGV);
1442 auto *SGVar = dyn_cast<GlobalVariable>(SGV);
1443 if (DGVar && SGVar && DGVar->isDeclaration() && SGVar->isDeclaration() &&
1444 (!DGVar->isConstant() || !SGVar->isConstant()))
1445 NewGVar->setConstant(false);
1448 if (NewGV != DGV && DGV) {
1449 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewGV, DGV->getType()));
1450 DGV->eraseFromParent();
1453 return ConstantExpr::getBitCast(NewGV, TypeMap.get(SGV->getType()));
1456 /// Update the initializers in the Dest module now that all globals that may be
1457 /// referenced are in Dest.
1458 void ModuleLinker::linkGlobalInit(GlobalVariable &Dst, GlobalVariable &Src) {
1459 // Figure out what the initializer looks like in the dest module.
1460 Dst.setInitializer(MapValue(Src.getInitializer(), ValueMap,
1461 RF_MoveDistinctMDs, &TypeMap, &ValMaterializer));
1464 /// Copy the source function over into the dest function and fix up references
1465 /// to values. At this point we know that Dest is an external function, and
1466 /// that Src is not.
1467 bool ModuleLinker::linkFunctionBody(Function &Dst, Function &Src) {
1468 assert(Dst.isDeclaration() && !Src.isDeclaration());
1470 // Materialize if needed.
1471 if (std::error_code EC = Src.materialize())
1472 return emitError(EC.message());
1474 // Link in the prefix data.
1475 if (Src.hasPrefixData())
1476 Dst.setPrefixData(MapValue(Src.getPrefixData(), ValueMap,
1477 RF_MoveDistinctMDs, &TypeMap, &ValMaterializer));
1479 // Link in the prologue data.
1480 if (Src.hasPrologueData())
1481 Dst.setPrologueData(MapValue(Src.getPrologueData(), ValueMap,
1482 RF_MoveDistinctMDs, &TypeMap,
1485 // Link in the personality function.
1486 if (Src.hasPersonalityFn())
1487 Dst.setPersonalityFn(MapValue(Src.getPersonalityFn(), ValueMap,
1488 RF_MoveDistinctMDs, &TypeMap,
1491 // Go through and convert function arguments over, remembering the mapping.
1492 Function::arg_iterator DI = Dst.arg_begin();
1493 for (Argument &Arg : Src.args()) {
1494 DI->setName(Arg.getName()); // Copy the name over.
1496 // Add a mapping to our mapping.
1497 ValueMap[&Arg] = &*DI;
1501 // Copy over the metadata attachments.
1502 SmallVector<std::pair<unsigned, MDNode *>, 8> MDs;
1503 Src.getAllMetadata(MDs);
1504 for (const auto &I : MDs)
1505 Dst.setMetadata(I.first, MapMetadata(I.second, ValueMap, RF_MoveDistinctMDs,
1506 &TypeMap, &ValMaterializer));
1508 // Splice the body of the source function into the dest function.
1509 Dst.getBasicBlockList().splice(Dst.end(), Src.getBasicBlockList());
1511 // At this point, all of the instructions and values of the function are now
1512 // copied over. The only problem is that they are still referencing values in
1513 // the Source function as operands. Loop through all of the operands of the
1514 // functions and patch them up to point to the local versions.
1515 for (BasicBlock &BB : Dst)
1516 for (Instruction &I : BB)
1517 RemapInstruction(&I, ValueMap,
1518 RF_IgnoreMissingEntries | RF_MoveDistinctMDs, &TypeMap,
1521 // There is no need to map the arguments anymore.
1522 for (Argument &Arg : Src.args())
1523 ValueMap.erase(&Arg);
1525 Src.dematerialize();
1529 void ModuleLinker::linkAliasBody(GlobalAlias &Dst, GlobalAlias &Src) {
1530 Constant *Aliasee = Src.getAliasee();
1531 Constant *Val = MapValue(Aliasee, ValueMap, RF_MoveDistinctMDs, &TypeMap,
1533 Dst.setAliasee(Val);
1536 bool ModuleLinker::linkGlobalValueBody(GlobalValue &Dst, GlobalValue &Src) {
1537 if (const Comdat *SC = Src.getComdat()) {
1538 // To ensure that we don't generate an incomplete comdat group,
1539 // we must materialize and map in any other members that are not
1540 // yet materialized in Dst, which also ensures their definitions
1541 // are linked in. Otherwise, linkonce and other lazy linked GVs will
1542 // not be materialized if they aren't referenced.
1543 for (auto *SGV : ComdatMembers[SC]) {
1544 auto *DGV = cast_or_null<GlobalValue>(ValueMap.lookup(SGV));
1545 if (DGV && !DGV->isDeclaration())
1547 MapValue(SGV, ValueMap, RF_MoveDistinctMDs, &TypeMap, &ValMaterializer);
1550 if (shouldInternalizeLinkedSymbols())
1551 if (auto *DGV = dyn_cast<GlobalValue>(&Dst))
1552 DGV->setLinkage(GlobalValue::InternalLinkage);
1553 if (auto *F = dyn_cast<Function>(&Src))
1554 return linkFunctionBody(cast<Function>(Dst), *F);
1555 if (auto *GVar = dyn_cast<GlobalVariable>(&Src)) {
1556 linkGlobalInit(cast<GlobalVariable>(Dst), *GVar);
1559 linkAliasBody(cast<GlobalAlias>(Dst), cast<GlobalAlias>(Src));
1563 /// Insert all of the named MDNodes in Src into the Dest module.
1564 void ModuleLinker::linkNamedMDNodes() {
1565 const NamedMDNode *SrcModFlags = SrcM.getModuleFlagsMetadata();
1566 for (const NamedMDNode &NMD : SrcM.named_metadata()) {
1567 // Don't link module flags here. Do them separately.
1568 if (&NMD == SrcModFlags)
1570 NamedMDNode *DestNMD = DstM.getOrInsertNamedMetadata(NMD.getName());
1571 // Add Src elements into Dest node.
1572 for (const MDNode *op : NMD.operands())
1573 DestNMD->addOperand(MapMetadata(
1574 op, ValueMap, RF_MoveDistinctMDs | RF_NullMapMissingGlobalValues,
1575 &TypeMap, &ValMaterializer));
1579 /// Merge the linker flags in Src into the Dest module.
1580 bool ModuleLinker::linkModuleFlagsMetadata() {
1581 // If the source module has no module flags, we are done.
1582 const NamedMDNode *SrcModFlags = SrcM.getModuleFlagsMetadata();
1586 // If the destination module doesn't have module flags yet, then just copy
1587 // over the source module's flags.
1588 NamedMDNode *DstModFlags = DstM.getOrInsertModuleFlagsMetadata();
1589 if (DstModFlags->getNumOperands() == 0) {
1590 for (unsigned I = 0, E = SrcModFlags->getNumOperands(); I != E; ++I)
1591 DstModFlags->addOperand(SrcModFlags->getOperand(I));
1596 // First build a map of the existing module flags and requirements.
1597 DenseMap<MDString *, std::pair<MDNode *, unsigned>> Flags;
1598 SmallSetVector<MDNode *, 16> Requirements;
1599 for (unsigned I = 0, E = DstModFlags->getNumOperands(); I != E; ++I) {
1600 MDNode *Op = DstModFlags->getOperand(I);
1601 ConstantInt *Behavior = mdconst::extract<ConstantInt>(Op->getOperand(0));
1602 MDString *ID = cast<MDString>(Op->getOperand(1));
1604 if (Behavior->getZExtValue() == Module::Require) {
1605 Requirements.insert(cast<MDNode>(Op->getOperand(2)));
1607 Flags[ID] = std::make_pair(Op, I);
1611 // Merge in the flags from the source module, and also collect its set of
1613 bool HasErr = false;
1614 for (unsigned I = 0, E = SrcModFlags->getNumOperands(); I != E; ++I) {
1615 MDNode *SrcOp = SrcModFlags->getOperand(I);
1616 ConstantInt *SrcBehavior =
1617 mdconst::extract<ConstantInt>(SrcOp->getOperand(0));
1618 MDString *ID = cast<MDString>(SrcOp->getOperand(1));
1621 std::tie(DstOp, DstIndex) = Flags.lookup(ID);
1622 unsigned SrcBehaviorValue = SrcBehavior->getZExtValue();
1624 // If this is a requirement, add it and continue.
1625 if (SrcBehaviorValue == Module::Require) {
1626 // If the destination module does not already have this requirement, add
1628 if (Requirements.insert(cast<MDNode>(SrcOp->getOperand(2)))) {
1629 DstModFlags->addOperand(SrcOp);
1634 // If there is no existing flag with this ID, just add it.
1636 Flags[ID] = std::make_pair(SrcOp, DstModFlags->getNumOperands());
1637 DstModFlags->addOperand(SrcOp);
1641 // Otherwise, perform a merge.
1642 ConstantInt *DstBehavior =
1643 mdconst::extract<ConstantInt>(DstOp->getOperand(0));
1644 unsigned DstBehaviorValue = DstBehavior->getZExtValue();
1646 // If either flag has override behavior, handle it first.
1647 if (DstBehaviorValue == Module::Override) {
1648 // Diagnose inconsistent flags which both have override behavior.
1649 if (SrcBehaviorValue == Module::Override &&
1650 SrcOp->getOperand(2) != DstOp->getOperand(2)) {
1651 HasErr |= emitError("linking module flags '" + ID->getString() +
1652 "': IDs have conflicting override values");
1655 } else if (SrcBehaviorValue == Module::Override) {
1656 // Update the destination flag to that of the source.
1657 DstModFlags->setOperand(DstIndex, SrcOp);
1658 Flags[ID].first = SrcOp;
1662 // Diagnose inconsistent merge behavior types.
1663 if (SrcBehaviorValue != DstBehaviorValue) {
1664 HasErr |= emitError("linking module flags '" + ID->getString() +
1665 "': IDs have conflicting behaviors");
1669 auto replaceDstValue = [&](MDNode *New) {
1670 Metadata *FlagOps[] = {DstOp->getOperand(0), ID, New};
1671 MDNode *Flag = MDNode::get(DstM.getContext(), FlagOps);
1672 DstModFlags->setOperand(DstIndex, Flag);
1673 Flags[ID].first = Flag;
1676 // Perform the merge for standard behavior types.
1677 switch (SrcBehaviorValue) {
1678 case Module::Require:
1679 case Module::Override:
1680 llvm_unreachable("not possible");
1681 case Module::Error: {
1682 // Emit an error if the values differ.
1683 if (SrcOp->getOperand(2) != DstOp->getOperand(2)) {
1684 HasErr |= emitError("linking module flags '" + ID->getString() +
1685 "': IDs have conflicting values");
1689 case Module::Warning: {
1690 // Emit a warning if the values differ.
1691 if (SrcOp->getOperand(2) != DstOp->getOperand(2)) {
1692 emitWarning("linking module flags '" + ID->getString() +
1693 "': IDs have conflicting values");
1697 case Module::Append: {
1698 MDNode *DstValue = cast<MDNode>(DstOp->getOperand(2));
1699 MDNode *SrcValue = cast<MDNode>(SrcOp->getOperand(2));
1700 SmallVector<Metadata *, 8> MDs;
1701 MDs.reserve(DstValue->getNumOperands() + SrcValue->getNumOperands());
1702 MDs.append(DstValue->op_begin(), DstValue->op_end());
1703 MDs.append(SrcValue->op_begin(), SrcValue->op_end());
1705 replaceDstValue(MDNode::get(DstM.getContext(), MDs));
1708 case Module::AppendUnique: {
1709 SmallSetVector<Metadata *, 16> Elts;
1710 MDNode *DstValue = cast<MDNode>(DstOp->getOperand(2));
1711 MDNode *SrcValue = cast<MDNode>(SrcOp->getOperand(2));
1712 Elts.insert(DstValue->op_begin(), DstValue->op_end());
1713 Elts.insert(SrcValue->op_begin(), SrcValue->op_end());
1715 replaceDstValue(MDNode::get(DstM.getContext(),
1716 makeArrayRef(Elts.begin(), Elts.end())));
1722 // Check all of the requirements.
1723 for (unsigned I = 0, E = Requirements.size(); I != E; ++I) {
1724 MDNode *Requirement = Requirements[I];
1725 MDString *Flag = cast<MDString>(Requirement->getOperand(0));
1726 Metadata *ReqValue = Requirement->getOperand(1);
1728 MDNode *Op = Flags[Flag].first;
1729 if (!Op || Op->getOperand(2) != ReqValue) {
1730 HasErr |= emitError("linking module flags '" + Flag->getString() +
1731 "': does not have the required value");
1739 // This function returns true if the triples match.
1740 static bool triplesMatch(const Triple &T0, const Triple &T1) {
1741 // If vendor is apple, ignore the version number.
1742 if (T0.getVendor() == Triple::Apple)
1743 return T0.getArch() == T1.getArch() && T0.getSubArch() == T1.getSubArch() &&
1744 T0.getVendor() == T1.getVendor() && T0.getOS() == T1.getOS();
1749 // This function returns the merged triple.
1750 static std::string mergeTriples(const Triple &SrcTriple,
1751 const Triple &DstTriple) {
1752 // If vendor is apple, pick the triple with the larger version number.
1753 if (SrcTriple.getVendor() == Triple::Apple)
1754 if (DstTriple.isOSVersionLT(SrcTriple))
1755 return SrcTriple.str();
1757 return DstTriple.str();
1760 bool ModuleLinker::linkIfNeeded(GlobalValue &GV) {
1761 GlobalValue *DGV = getLinkedToGlobal(&GV);
1763 if (shouldLinkOnlyNeeded() && !(DGV && DGV->isDeclaration()))
1766 if (DGV && !GV.hasLocalLinkage() && !GV.hasAppendingLinkage()) {
1767 auto *DGVar = dyn_cast<GlobalVariable>(DGV);
1768 auto *SGVar = dyn_cast<GlobalVariable>(&GV);
1769 if (DGVar && SGVar) {
1770 if (DGVar->isDeclaration() && SGVar->isDeclaration() &&
1771 (!DGVar->isConstant() || !SGVar->isConstant())) {
1772 DGVar->setConstant(false);
1773 SGVar->setConstant(false);
1775 if (DGVar->hasCommonLinkage() && SGVar->hasCommonLinkage()) {
1776 unsigned Align = std::max(DGVar->getAlignment(), SGVar->getAlignment());
1777 SGVar->setAlignment(Align);
1778 DGVar->setAlignment(Align);
1782 GlobalValue::VisibilityTypes Visibility =
1783 getMinVisibility(DGV->getVisibility(), GV.getVisibility());
1784 DGV->setVisibility(Visibility);
1785 GV.setVisibility(Visibility);
1787 bool HasUnnamedAddr = GV.hasUnnamedAddr() && DGV->hasUnnamedAddr();
1788 DGV->setUnnamedAddr(HasUnnamedAddr);
1789 GV.setUnnamedAddr(HasUnnamedAddr);
1792 // Don't want to append to global_ctors list, for example, when we
1793 // are importing for ThinLTO, otherwise the global ctors and dtors
1794 // get executed multiple times for local variables (the latter causing
1796 if (GV.hasAppendingLinkage() && isPerformingImport())
1799 if (isPerformingImport() && !doImportAsDefinition(&GV))
1802 if (!DGV && !shouldOverrideFromSrc() &&
1803 (GV.hasLocalLinkage() || GV.hasLinkOnceLinkage() ||
1804 GV.hasAvailableExternallyLinkage()))
1807 if (const Comdat *SC = GV.getComdat()) {
1809 Comdat::SelectionKind SK;
1810 std::tie(SK, LinkFromSrc) = ComdatsChosen[SC];
1812 ValuesToLink.insert(&GV);
1816 bool LinkFromSrc = true;
1817 if (DGV && shouldLinkFromSource(LinkFromSrc, *DGV, GV))
1820 ValuesToLink.insert(&GV);
1824 bool ModuleLinker::run() {
1825 // Inherit the target data from the source module if the destination module
1826 // doesn't have one already.
1827 if (DstM.getDataLayout().isDefault())
1828 DstM.setDataLayout(SrcM.getDataLayout());
1830 if (SrcM.getDataLayout() != DstM.getDataLayout()) {
1831 emitWarning("Linking two modules of different data layouts: '" +
1832 SrcM.getModuleIdentifier() + "' is '" +
1833 SrcM.getDataLayoutStr() + "' whereas '" +
1834 DstM.getModuleIdentifier() + "' is '" +
1835 DstM.getDataLayoutStr() + "'\n");
1838 // Copy the target triple from the source to dest if the dest's is empty.
1839 if (DstM.getTargetTriple().empty() && !SrcM.getTargetTriple().empty())
1840 DstM.setTargetTriple(SrcM.getTargetTriple());
1842 Triple SrcTriple(SrcM.getTargetTriple()), DstTriple(DstM.getTargetTriple());
1844 if (!SrcM.getTargetTriple().empty() && !triplesMatch(SrcTriple, DstTriple))
1845 emitWarning("Linking two modules of different target triples: " +
1846 SrcM.getModuleIdentifier() + "' is '" + SrcM.getTargetTriple() +
1847 "' whereas '" + DstM.getModuleIdentifier() + "' is '" +
1848 DstM.getTargetTriple() + "'\n");
1850 DstM.setTargetTriple(mergeTriples(SrcTriple, DstTriple));
1852 // Append the module inline asm string.
1853 if (!SrcM.getModuleInlineAsm().empty()) {
1854 if (DstM.getModuleInlineAsm().empty())
1855 DstM.setModuleInlineAsm(SrcM.getModuleInlineAsm());
1857 DstM.setModuleInlineAsm(DstM.getModuleInlineAsm() + "\n" +
1858 SrcM.getModuleInlineAsm());
1861 // Loop over all of the linked values to compute type mappings.
1862 computeTypeMapping();
1864 ComdatsChosen.clear();
1865 for (const auto &SMEC : SrcM.getComdatSymbolTable()) {
1866 const Comdat &C = SMEC.getValue();
1867 if (ComdatsChosen.count(&C))
1869 Comdat::SelectionKind SK;
1871 if (getComdatResult(&C, SK, LinkFromSrc))
1873 ComdatsChosen[&C] = std::make_pair(SK, LinkFromSrc);
1876 // Upgrade mismatched global arrays.
1877 upgradeMismatchedGlobals();
1879 for (GlobalVariable &GV : SrcM.globals())
1880 if (const Comdat *SC = GV.getComdat())
1881 ComdatMembers[SC].push_back(&GV);
1883 for (Function &SF : SrcM)
1884 if (const Comdat *SC = SF.getComdat())
1885 ComdatMembers[SC].push_back(&SF);
1887 for (GlobalAlias &GA : SrcM.aliases())
1888 if (const Comdat *SC = GA.getComdat())
1889 ComdatMembers[SC].push_back(&GA);
1891 // Insert all of the globals in src into the DstM module... without linking
1892 // initializers (which could refer to functions not yet mapped over).
1893 for (GlobalVariable &GV : SrcM.globals())
1894 if (linkIfNeeded(GV))
1897 for (Function &SF : SrcM)
1898 if (linkIfNeeded(SF))
1901 for (GlobalAlias &GA : SrcM.aliases())
1902 if (linkIfNeeded(GA))
1905 for (GlobalValue *GV : ValuesToLink) {
1906 MapValue(GV, ValueMap, RF_MoveDistinctMDs, &TypeMap, &ValMaterializer);
1911 // Note that we are done linking global value bodies. This prevents
1912 // metadata linking from creating new references.
1913 DoneLinkingBodies = true;
1915 // Remap all of the named MDNodes in Src into the DstM module. We do this
1916 // after linking GlobalValues so that MDNodes that reference GlobalValues
1917 // are properly remapped.
1920 // Merge the module flags into the DstM module.
1921 if (linkModuleFlagsMetadata())
1927 Linker::StructTypeKeyInfo::KeyTy::KeyTy(ArrayRef<Type *> E, bool P)
1928 : ETypes(E), IsPacked(P) {}
1930 Linker::StructTypeKeyInfo::KeyTy::KeyTy(const StructType *ST)
1931 : ETypes(ST->elements()), IsPacked(ST->isPacked()) {}
1933 bool Linker::StructTypeKeyInfo::KeyTy::operator==(const KeyTy &That) const {
1934 if (IsPacked != That.IsPacked)
1936 if (ETypes != That.ETypes)
1941 bool Linker::StructTypeKeyInfo::KeyTy::operator!=(const KeyTy &That) const {
1942 return !this->operator==(That);
1945 StructType *Linker::StructTypeKeyInfo::getEmptyKey() {
1946 return DenseMapInfo<StructType *>::getEmptyKey();
1949 StructType *Linker::StructTypeKeyInfo::getTombstoneKey() {
1950 return DenseMapInfo<StructType *>::getTombstoneKey();
1953 unsigned Linker::StructTypeKeyInfo::getHashValue(const KeyTy &Key) {
1954 return hash_combine(hash_combine_range(Key.ETypes.begin(), Key.ETypes.end()),
1958 unsigned Linker::StructTypeKeyInfo::getHashValue(const StructType *ST) {
1959 return getHashValue(KeyTy(ST));
1962 bool Linker::StructTypeKeyInfo::isEqual(const KeyTy &LHS,
1963 const StructType *RHS) {
1964 if (RHS == getEmptyKey() || RHS == getTombstoneKey())
1966 return LHS == KeyTy(RHS);
1969 bool Linker::StructTypeKeyInfo::isEqual(const StructType *LHS,
1970 const StructType *RHS) {
1971 if (RHS == getEmptyKey())
1972 return LHS == getEmptyKey();
1974 if (RHS == getTombstoneKey())
1975 return LHS == getTombstoneKey();
1977 return KeyTy(LHS) == KeyTy(RHS);
1980 void Linker::IdentifiedStructTypeSet::addNonOpaque(StructType *Ty) {
1981 assert(!Ty->isOpaque());
1982 NonOpaqueStructTypes.insert(Ty);
1985 void Linker::IdentifiedStructTypeSet::switchToNonOpaque(StructType *Ty) {
1986 assert(!Ty->isOpaque());
1987 NonOpaqueStructTypes.insert(Ty);
1988 bool Removed = OpaqueStructTypes.erase(Ty);
1993 void Linker::IdentifiedStructTypeSet::addOpaque(StructType *Ty) {
1994 assert(Ty->isOpaque());
1995 OpaqueStructTypes.insert(Ty);
1999 Linker::IdentifiedStructTypeSet::findNonOpaque(ArrayRef<Type *> ETypes,
2001 Linker::StructTypeKeyInfo::KeyTy Key(ETypes, IsPacked);
2002 auto I = NonOpaqueStructTypes.find_as(Key);
2003 if (I == NonOpaqueStructTypes.end())
2008 bool Linker::IdentifiedStructTypeSet::hasType(StructType *Ty) {
2010 return OpaqueStructTypes.count(Ty);
2011 auto I = NonOpaqueStructTypes.find(Ty);
2012 if (I == NonOpaqueStructTypes.end())
2017 Linker::Linker(Module &M, DiagnosticHandlerFunction DiagnosticHandler)
2018 : Composite(M), DiagnosticHandler(DiagnosticHandler) {
2019 TypeFinder StructTypes;
2020 StructTypes.run(M, true);
2021 for (StructType *Ty : StructTypes) {
2023 IdentifiedStructTypes.addOpaque(Ty);
2025 IdentifiedStructTypes.addNonOpaque(Ty);
2029 Linker::Linker(Module &M)
2030 : Linker(M, [this](const DiagnosticInfo &DI) {
2031 Composite.getContext().diagnose(DI);
2034 bool Linker::linkInModule(Module &Src, unsigned Flags,
2035 const FunctionInfoIndex *Index,
2036 DenseSet<const GlobalValue *> *FunctionsToImport) {
2037 ModuleLinker TheLinker(Composite, IdentifiedStructTypes, Src,
2038 DiagnosticHandler, Flags, Index, FunctionsToImport);
2039 bool RetCode = TheLinker.run();
2040 Composite.dropTriviallyDeadConstantArrays();
2044 //===----------------------------------------------------------------------===//
2045 // LinkModules entrypoint.
2046 //===----------------------------------------------------------------------===//
2048 /// This function links two modules together, with the resulting Dest module
2049 /// modified to be the composite of the two input modules. If an error occurs,
2050 /// true is returned and ErrorMsg (if not null) is set to indicate the problem.
2051 /// Upon failure, the Dest module could be in a modified state, and shouldn't be
2052 /// relied on to be consistent.
2053 bool Linker::linkModules(Module &Dest, Module &Src,
2054 DiagnosticHandlerFunction DiagnosticHandler,
2056 Linker L(Dest, DiagnosticHandler);
2057 return L.linkInModule(Src, Flags);
2060 bool Linker::linkModules(Module &Dest, Module &Src, unsigned Flags) {
2062 return L.linkInModule(Src, Flags);
2065 //===----------------------------------------------------------------------===//
2067 //===----------------------------------------------------------------------===//
2069 LLVMBool LLVMLinkModules(LLVMModuleRef Dest, LLVMModuleRef Src,
2070 LLVMLinkerMode Unused, char **OutMessages) {
2071 Module *D = unwrap(Dest);
2072 std::string Message;
2073 raw_string_ostream Stream(Message);
2074 DiagnosticPrinterRawOStream DP(Stream);
2076 LLVMBool Result = Linker::linkModules(
2077 *D, *unwrap(Src), [&](const DiagnosticInfo &DI) { DI.print(DP); });
2079 if (OutMessages && Result) {
2081 *OutMessages = strdup(Message.c_str());