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 bool linkAppendingVarProto(GlobalVariable *DstGV,
517 const GlobalVariable *SrcGV);
519 bool 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 linkGlobalValueProto(SGV);
860 return ValueMap[SGV];
863 void ValueMaterializerTy::materializeInitFor(GlobalValue *New,
865 return ModLinker->materializeInitFor(New, Old);
868 static bool shouldLazyLink(const GlobalValue &GV) {
869 return GV.hasLocalLinkage() || GV.hasLinkOnceLinkage() ||
870 GV.hasAvailableExternallyLinkage();
873 void ModuleLinker::materializeInitFor(GlobalValue *New, GlobalValue *Old) {
874 if (auto *F = dyn_cast<Function>(New)) {
875 if (!F->isDeclaration())
877 } else if (auto *V = dyn_cast<GlobalVariable>(New)) {
878 if (V->hasInitializer())
881 auto *A = cast<GlobalAlias>(New);
886 if (Old->isDeclaration())
889 if (isPerformingImport() && !doImportAsDefinition(Old))
892 if (!ValuesToLink.count(Old) && !shouldLazyLink(*Old))
895 linkGlobalValueBody(*New, *Old);
898 bool ModuleLinker::getComdatLeader(Module &M, StringRef ComdatName,
899 const GlobalVariable *&GVar) {
900 const GlobalValue *GVal = M.getNamedValue(ComdatName);
901 if (const auto *GA = dyn_cast_or_null<GlobalAlias>(GVal)) {
902 GVal = GA->getBaseObject();
904 // We cannot resolve the size of the aliasee yet.
905 return emitError("Linking COMDATs named '" + ComdatName +
906 "': COMDAT key involves incomputable alias size.");
909 GVar = dyn_cast_or_null<GlobalVariable>(GVal);
912 "Linking COMDATs named '" + ComdatName +
913 "': GlobalVariable required for data dependent selection!");
918 bool ModuleLinker::computeResultingSelectionKind(StringRef ComdatName,
919 Comdat::SelectionKind Src,
920 Comdat::SelectionKind Dst,
921 Comdat::SelectionKind &Result,
923 // The ability to mix Comdat::SelectionKind::Any with
924 // Comdat::SelectionKind::Largest is a behavior that comes from COFF.
925 bool DstAnyOrLargest = Dst == Comdat::SelectionKind::Any ||
926 Dst == Comdat::SelectionKind::Largest;
927 bool SrcAnyOrLargest = Src == Comdat::SelectionKind::Any ||
928 Src == Comdat::SelectionKind::Largest;
929 if (DstAnyOrLargest && SrcAnyOrLargest) {
930 if (Dst == Comdat::SelectionKind::Largest ||
931 Src == Comdat::SelectionKind::Largest)
932 Result = Comdat::SelectionKind::Largest;
934 Result = Comdat::SelectionKind::Any;
935 } else if (Src == Dst) {
938 return emitError("Linking COMDATs named '" + ComdatName +
939 "': invalid selection kinds!");
943 case Comdat::SelectionKind::Any:
947 case Comdat::SelectionKind::NoDuplicates:
948 return emitError("Linking COMDATs named '" + ComdatName +
949 "': noduplicates has been violated!");
950 case Comdat::SelectionKind::ExactMatch:
951 case Comdat::SelectionKind::Largest:
952 case Comdat::SelectionKind::SameSize: {
953 const GlobalVariable *DstGV;
954 const GlobalVariable *SrcGV;
955 if (getComdatLeader(DstM, ComdatName, DstGV) ||
956 getComdatLeader(SrcM, ComdatName, SrcGV))
959 const DataLayout &DstDL = DstM.getDataLayout();
960 const DataLayout &SrcDL = SrcM.getDataLayout();
962 DstDL.getTypeAllocSize(DstGV->getType()->getPointerElementType());
964 SrcDL.getTypeAllocSize(SrcGV->getType()->getPointerElementType());
965 if (Result == Comdat::SelectionKind::ExactMatch) {
966 if (SrcGV->getInitializer() != DstGV->getInitializer())
967 return emitError("Linking COMDATs named '" + ComdatName +
968 "': ExactMatch violated!");
970 } else if (Result == Comdat::SelectionKind::Largest) {
971 LinkFromSrc = SrcSize > DstSize;
972 } else if (Result == Comdat::SelectionKind::SameSize) {
973 if (SrcSize != DstSize)
974 return emitError("Linking COMDATs named '" + ComdatName +
975 "': SameSize violated!");
978 llvm_unreachable("unknown selection kind");
987 bool ModuleLinker::getComdatResult(const Comdat *SrcC,
988 Comdat::SelectionKind &Result,
990 Comdat::SelectionKind SSK = SrcC->getSelectionKind();
991 StringRef ComdatName = SrcC->getName();
992 Module::ComdatSymTabType &ComdatSymTab = DstM.getComdatSymbolTable();
993 Module::ComdatSymTabType::iterator DstCI = ComdatSymTab.find(ComdatName);
995 if (DstCI == ComdatSymTab.end()) {
996 // Use the comdat if it is only available in one of the modules.
1002 const Comdat *DstC = &DstCI->second;
1003 Comdat::SelectionKind DSK = DstC->getSelectionKind();
1004 return computeResultingSelectionKind(ComdatName, SSK, DSK, Result,
1008 bool ModuleLinker::shouldLinkFromSource(bool &LinkFromSrc,
1009 const GlobalValue &Dest,
1010 const GlobalValue &Src) {
1011 // Should we unconditionally use the Src?
1012 if (shouldOverrideFromSrc()) {
1017 // We always have to add Src if it has appending linkage.
1018 if (Src.hasAppendingLinkage()) {
1019 // Caller should have already determined that we can't link from source
1020 // when importing (see comments in linkGlobalValueProto).
1021 assert(!isPerformingImport());
1026 bool SrcIsDeclaration = Src.isDeclarationForLinker();
1027 bool DestIsDeclaration = Dest.isDeclarationForLinker();
1029 if (isPerformingImport()) {
1030 if (isa<Function>(&Src)) {
1031 // For functions, LinkFromSrc iff this is the function requested
1032 // for importing. For variables, decide below normally.
1033 LinkFromSrc = ImportFunction->count(&Src);
1037 // Check if this is an alias with an already existing definition
1038 // in Dest, which must have come from a prior importing pass from
1039 // the same Src module. Unlike imported function and variable
1040 // definitions, which are imported as available_externally and are
1041 // not definitions for the linker, that is not a valid linkage for
1042 // imported aliases which must be definitions. Simply use the existing
1044 if (isa<GlobalAlias>(&Src) && !DestIsDeclaration) {
1045 assert(isa<GlobalAlias>(&Dest));
1046 LinkFromSrc = false;
1051 if (SrcIsDeclaration) {
1052 // If Src is external or if both Src & Dest are external.. Just link the
1053 // external globals, we aren't adding anything.
1054 if (Src.hasDLLImportStorageClass()) {
1055 // If one of GVs is marked as DLLImport, result should be dllimport'ed.
1056 LinkFromSrc = DestIsDeclaration;
1059 // If the Dest is weak, use the source linkage.
1060 LinkFromSrc = Dest.hasExternalWeakLinkage();
1064 if (DestIsDeclaration) {
1065 // If Dest is external but Src is not:
1070 if (Src.hasCommonLinkage()) {
1071 if (Dest.hasLinkOnceLinkage() || Dest.hasWeakLinkage()) {
1076 if (!Dest.hasCommonLinkage()) {
1077 LinkFromSrc = false;
1081 const DataLayout &DL = Dest.getParent()->getDataLayout();
1082 uint64_t DestSize = DL.getTypeAllocSize(Dest.getType()->getElementType());
1083 uint64_t SrcSize = DL.getTypeAllocSize(Src.getType()->getElementType());
1084 LinkFromSrc = SrcSize > DestSize;
1088 if (Src.isWeakForLinker()) {
1089 assert(!Dest.hasExternalWeakLinkage());
1090 assert(!Dest.hasAvailableExternallyLinkage());
1092 if (Dest.hasLinkOnceLinkage() && Src.hasWeakLinkage()) {
1097 LinkFromSrc = false;
1101 if (Dest.isWeakForLinker()) {
1102 assert(Src.hasExternalLinkage());
1107 assert(!Src.hasExternalWeakLinkage());
1108 assert(!Dest.hasExternalWeakLinkage());
1109 assert(Dest.hasExternalLinkage() && Src.hasExternalLinkage() &&
1110 "Unexpected linkage type!");
1111 return emitError("Linking globals named '" + Src.getName() +
1112 "': symbol multiply defined!");
1115 /// Loop over all of the linked values to compute type mappings. For example,
1116 /// if we link "extern Foo *x" and "Foo *x = NULL", then we have two struct
1117 /// types 'Foo' but one got renamed when the module was loaded into the same
1119 void ModuleLinker::computeTypeMapping() {
1120 for (GlobalValue &SGV : SrcM.globals()) {
1121 GlobalValue *DGV = getLinkedToGlobal(&SGV);
1125 if (!DGV->hasAppendingLinkage() || !SGV.hasAppendingLinkage()) {
1126 TypeMap.addTypeMapping(DGV->getType(), SGV.getType());
1130 // Unify the element type of appending arrays.
1131 ArrayType *DAT = cast<ArrayType>(DGV->getType()->getElementType());
1132 ArrayType *SAT = cast<ArrayType>(SGV.getType()->getElementType());
1133 TypeMap.addTypeMapping(DAT->getElementType(), SAT->getElementType());
1136 for (GlobalValue &SGV : SrcM) {
1137 if (GlobalValue *DGV = getLinkedToGlobal(&SGV))
1138 TypeMap.addTypeMapping(DGV->getType(), SGV.getType());
1141 for (GlobalValue &SGV : SrcM.aliases()) {
1142 if (GlobalValue *DGV = getLinkedToGlobal(&SGV))
1143 TypeMap.addTypeMapping(DGV->getType(), SGV.getType());
1146 // Incorporate types by name, scanning all the types in the source module.
1147 // At this point, the destination module may have a type "%foo = { i32 }" for
1148 // example. When the source module got loaded into the same LLVMContext, if
1149 // it had the same type, it would have been renamed to "%foo.42 = { i32 }".
1150 std::vector<StructType *> Types = SrcM.getIdentifiedStructTypes();
1151 for (StructType *ST : Types) {
1155 // Check to see if there is a dot in the name followed by a digit.
1156 size_t DotPos = ST->getName().rfind('.');
1157 if (DotPos == 0 || DotPos == StringRef::npos ||
1158 ST->getName().back() == '.' ||
1159 !isdigit(static_cast<unsigned char>(ST->getName()[DotPos + 1])))
1162 // Check to see if the destination module has a struct with the prefix name.
1163 StructType *DST = DstM.getTypeByName(ST->getName().substr(0, DotPos));
1167 // Don't use it if this actually came from the source module. They're in
1168 // the same LLVMContext after all. Also don't use it unless the type is
1169 // actually used in the destination module. This can happen in situations
1172 // Module A Module B
1173 // -------- --------
1174 // %Z = type { %A } %B = type { %C.1 }
1175 // %A = type { %B.1, [7 x i8] } %C.1 = type { i8* }
1176 // %B.1 = type { %C } %A.2 = type { %B.3, [5 x i8] }
1177 // %C = type { i8* } %B.3 = type { %C.1 }
1179 // When we link Module B with Module A, the '%B' in Module B is
1180 // used. However, that would then use '%C.1'. But when we process '%C.1',
1181 // we prefer to take the '%C' version. So we are then left with both
1182 // '%C.1' and '%C' being used for the same types. This leads to some
1183 // variables using one type and some using the other.
1184 if (TypeMap.DstStructTypesSet.hasType(DST))
1185 TypeMap.addTypeMapping(DST, ST);
1188 // Now that we have discovered all of the type equivalences, get a body for
1189 // any 'opaque' types in the dest module that are now resolved.
1190 TypeMap.linkDefinedTypeBodies();
1193 static void upgradeGlobalArray(GlobalVariable *GV) {
1194 ArrayType *ATy = cast<ArrayType>(GV->getType()->getElementType());
1195 StructType *OldTy = cast<StructType>(ATy->getElementType());
1196 assert(OldTy->getNumElements() == 2 && "Expected to upgrade from 2 elements");
1198 // Get the upgraded 3 element type.
1199 PointerType *VoidPtrTy = Type::getInt8Ty(GV->getContext())->getPointerTo();
1200 Type *Tys[3] = {OldTy->getElementType(0), OldTy->getElementType(1),
1202 StructType *NewTy = StructType::get(GV->getContext(), Tys, false);
1204 // Build new constants with a null third field filled in.
1205 Constant *OldInitC = GV->getInitializer();
1206 ConstantArray *OldInit = dyn_cast<ConstantArray>(OldInitC);
1207 if (!OldInit && !isa<ConstantAggregateZero>(OldInitC))
1208 // Invalid initializer; give up.
1210 std::vector<Constant *> Initializers;
1211 if (OldInit && OldInit->getNumOperands()) {
1212 Value *Null = Constant::getNullValue(VoidPtrTy);
1213 for (Use &U : OldInit->operands()) {
1214 ConstantStruct *Init = cast<ConstantStruct>(U.get());
1215 Initializers.push_back(ConstantStruct::get(
1216 NewTy, Init->getOperand(0), Init->getOperand(1), Null, nullptr));
1219 assert(Initializers.size() == ATy->getNumElements() &&
1220 "Failed to copy all array elements");
1222 // Replace the old GV with a new one.
1223 ATy = ArrayType::get(NewTy, Initializers.size());
1224 Constant *NewInit = ConstantArray::get(ATy, Initializers);
1225 GlobalVariable *NewGV = new GlobalVariable(
1226 *GV->getParent(), ATy, GV->isConstant(), GV->getLinkage(), NewInit, "",
1227 GV, GV->getThreadLocalMode(), GV->getType()->getAddressSpace(),
1228 GV->isExternallyInitialized());
1229 NewGV->copyAttributesFrom(GV);
1230 NewGV->takeName(GV);
1231 assert(GV->use_empty() && "program cannot use initializer list");
1232 GV->eraseFromParent();
1235 void ModuleLinker::upgradeMismatchedGlobalArray(StringRef Name) {
1236 // Look for the global arrays.
1237 auto *DstGV = dyn_cast_or_null<GlobalVariable>(DstM.getNamedValue(Name));
1240 auto *SrcGV = dyn_cast_or_null<GlobalVariable>(SrcM.getNamedValue(Name));
1244 // Check if the types already match.
1245 auto *DstTy = cast<ArrayType>(DstGV->getType()->getElementType());
1247 cast<ArrayType>(TypeMap.get(SrcGV->getType()->getElementType()));
1251 // Grab the element types. We can only upgrade an array of a two-field
1252 // struct. Only bother if the other one has three-fields.
1253 auto *DstEltTy = cast<StructType>(DstTy->getElementType());
1254 auto *SrcEltTy = cast<StructType>(SrcTy->getElementType());
1255 if (DstEltTy->getNumElements() == 2 && SrcEltTy->getNumElements() == 3) {
1256 upgradeGlobalArray(DstGV);
1259 if (DstEltTy->getNumElements() == 3 && SrcEltTy->getNumElements() == 2)
1260 upgradeGlobalArray(SrcGV);
1262 // We can't upgrade any other differences.
1265 void ModuleLinker::upgradeMismatchedGlobals() {
1266 upgradeMismatchedGlobalArray("llvm.global_ctors");
1267 upgradeMismatchedGlobalArray("llvm.global_dtors");
1270 static void getArrayElements(const Constant *C,
1271 SmallVectorImpl<Constant *> &Dest) {
1272 unsigned NumElements = cast<ArrayType>(C->getType())->getNumElements();
1274 for (unsigned i = 0; i != NumElements; ++i)
1275 Dest.push_back(C->getAggregateElement(i));
1278 /// If there were any appending global variables, link them together now.
1279 /// Return true on error.
1280 bool ModuleLinker::linkAppendingVarProto(GlobalVariable *DstGV,
1281 const GlobalVariable *SrcGV) {
1283 cast<ArrayType>(TypeMap.get(SrcGV->getType()->getElementType()));
1284 Type *EltTy = SrcTy->getElementType();
1287 ArrayType *DstTy = cast<ArrayType>(DstGV->getType()->getElementType());
1289 if (!SrcGV->hasAppendingLinkage() || !DstGV->hasAppendingLinkage())
1291 "Linking globals named '" + SrcGV->getName() +
1292 "': can only link appending global with another appending global!");
1294 // Check to see that they two arrays agree on type.
1295 if (EltTy != DstTy->getElementType())
1296 return emitError("Appending variables with different element types!");
1297 if (DstGV->isConstant() != SrcGV->isConstant())
1298 return emitError("Appending variables linked with different const'ness!");
1300 if (DstGV->getAlignment() != SrcGV->getAlignment())
1302 "Appending variables with different alignment need to be linked!");
1304 if (DstGV->getVisibility() != SrcGV->getVisibility())
1306 "Appending variables with different visibility need to be linked!");
1308 if (DstGV->hasUnnamedAddr() != SrcGV->hasUnnamedAddr())
1310 "Appending variables with different unnamed_addr need to be linked!");
1312 if (StringRef(DstGV->getSection()) != SrcGV->getSection())
1314 "Appending variables with different section name need to be linked!");
1317 SmallVector<Constant *, 16> DstElements;
1319 getArrayElements(DstGV->getInitializer(), DstElements);
1321 SmallVector<Constant *, 16> SrcElements;
1322 getArrayElements(SrcGV->getInitializer(), SrcElements);
1324 StringRef Name = SrcGV->getName();
1325 bool IsNewStructor =
1326 (Name == "llvm.global_ctors" || Name == "llvm.global_dtors") &&
1327 cast<StructType>(EltTy)->getNumElements() == 3;
1330 std::remove_if(SrcElements.begin(), SrcElements.end(),
1331 [this](Constant *E) {
1332 auto *Key = dyn_cast<GlobalValue>(
1333 E->getAggregateElement(2)->stripPointerCasts());
1334 return Key && !ValuesToLink.count(Key) &&
1335 !shouldLazyLink(*Key);
1338 uint64_t NewSize = DstElements.size() + SrcElements.size();
1339 ArrayType *NewType = ArrayType::get(EltTy, NewSize);
1341 // Create the new global variable.
1342 GlobalVariable *NG = new GlobalVariable(
1343 DstM, NewType, SrcGV->isConstant(), SrcGV->getLinkage(),
1344 /*init*/ nullptr, /*name*/ "", DstGV, SrcGV->getThreadLocalMode(),
1345 SrcGV->getType()->getAddressSpace());
1347 // Propagate alignment, visibility and section info.
1348 copyGVAttributes(NG, SrcGV);
1350 // Replace any uses of the two global variables with uses of the new
1352 ValueMap[SrcGV] = ConstantExpr::getBitCast(NG, TypeMap.get(SrcGV->getType()));
1354 for (auto *V : SrcElements) {
1355 DstElements.push_back(
1356 MapValue(V, ValueMap, RF_MoveDistinctMDs, &TypeMap, &ValMaterializer));
1359 NG->setInitializer(ConstantArray::get(NewType, DstElements));
1362 DstGV->replaceAllUsesWith(ConstantExpr::getBitCast(NG, DstGV->getType()));
1363 DstGV->eraseFromParent();
1369 bool ModuleLinker::linkGlobalValueProto(GlobalValue *SGV) {
1370 GlobalValue *DGV = getLinkedToGlobal(SGV);
1372 // Handle the ultra special appending linkage case first.
1373 assert(!DGV || SGV->hasAppendingLinkage() == DGV->hasAppendingLinkage());
1374 if (SGV->hasAppendingLinkage())
1375 return linkAppendingVarProto(cast_or_null<GlobalVariable>(DGV),
1376 cast<GlobalVariable>(SGV));
1378 bool LinkFromSrc = true;
1379 Comdat *C = nullptr;
1380 bool HasUnnamedAddr = SGV->hasUnnamedAddr();
1382 if (isPerformingImport() && !doImportAsDefinition(SGV)) {
1383 LinkFromSrc = false;
1384 } else if (const Comdat *SC = SGV->getComdat()) {
1385 Comdat::SelectionKind SK;
1386 std::tie(SK, LinkFromSrc) = ComdatsChosen[SC];
1387 C = DstM.getOrInsertComdat(SC->getName());
1388 C->setSelectionKind(SK);
1389 if (SGV->hasLocalLinkage())
1392 if (shouldLinkFromSource(LinkFromSrc, *DGV, *SGV))
1396 if (!LinkFromSrc && DGV) {
1397 // Make sure to remember this mapping.
1398 ValueMap[SGV] = ConstantExpr::getBitCast(DGV, TypeMap.get(SGV->getType()));
1402 HasUnnamedAddr = HasUnnamedAddr && DGV->hasUnnamedAddr();
1405 if (!LinkFromSrc && DGV) {
1407 // When linking from source we setVisibility from copyGlobalValueProto.
1408 setVisibility(NewGV, SGV, DGV);
1410 // If we are done linking global value bodies (i.e. we are performing
1411 // metadata linking), don't link in the global value due to this
1412 // reference, simply map it to null.
1413 if (DoneLinkingBodies)
1416 NewGV = copyGlobalValueProto(SGV, DGV, LinkFromSrc);
1419 NewGV->setUnnamedAddr(HasUnnamedAddr);
1421 if (auto *NewGO = dyn_cast<GlobalObject>(NewGV)) {
1422 if (C && LinkFromSrc)
1423 NewGO->setComdat(C);
1425 if (DGV && DGV->hasCommonLinkage() && SGV->hasCommonLinkage())
1426 NewGO->setAlignment(std::max(DGV->getAlignment(), SGV->getAlignment()));
1429 if (auto *NewGVar = dyn_cast<GlobalVariable>(NewGV)) {
1430 auto *DGVar = dyn_cast_or_null<GlobalVariable>(DGV);
1431 auto *SGVar = dyn_cast<GlobalVariable>(SGV);
1432 if (DGVar && SGVar && DGVar->isDeclaration() && SGVar->isDeclaration() &&
1433 (!DGVar->isConstant() || !SGVar->isConstant()))
1434 NewGVar->setConstant(false);
1437 // Make sure to remember this mapping.
1440 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewGV, DGV->getType()));
1441 DGV->eraseFromParent();
1443 ValueMap[SGV] = NewGV;
1449 /// Update the initializers in the Dest module now that all globals that may be
1450 /// referenced are in Dest.
1451 void ModuleLinker::linkGlobalInit(GlobalVariable &Dst, GlobalVariable &Src) {
1452 // Figure out what the initializer looks like in the dest module.
1453 Dst.setInitializer(MapValue(Src.getInitializer(), ValueMap,
1454 RF_MoveDistinctMDs, &TypeMap, &ValMaterializer));
1457 /// Copy the source function over into the dest function and fix up references
1458 /// to values. At this point we know that Dest is an external function, and
1459 /// that Src is not.
1460 bool ModuleLinker::linkFunctionBody(Function &Dst, Function &Src) {
1461 assert(Dst.isDeclaration() && !Src.isDeclaration());
1463 // Materialize if needed.
1464 if (std::error_code EC = Src.materialize())
1465 return emitError(EC.message());
1467 // Link in the prefix data.
1468 if (Src.hasPrefixData())
1469 Dst.setPrefixData(MapValue(Src.getPrefixData(), ValueMap,
1470 RF_MoveDistinctMDs, &TypeMap, &ValMaterializer));
1472 // Link in the prologue data.
1473 if (Src.hasPrologueData())
1474 Dst.setPrologueData(MapValue(Src.getPrologueData(), ValueMap,
1475 RF_MoveDistinctMDs, &TypeMap,
1478 // Link in the personality function.
1479 if (Src.hasPersonalityFn())
1480 Dst.setPersonalityFn(MapValue(Src.getPersonalityFn(), ValueMap,
1481 RF_MoveDistinctMDs, &TypeMap,
1484 // Go through and convert function arguments over, remembering the mapping.
1485 Function::arg_iterator DI = Dst.arg_begin();
1486 for (Argument &Arg : Src.args()) {
1487 DI->setName(Arg.getName()); // Copy the name over.
1489 // Add a mapping to our mapping.
1490 ValueMap[&Arg] = &*DI;
1494 // Copy over the metadata attachments.
1495 SmallVector<std::pair<unsigned, MDNode *>, 8> MDs;
1496 Src.getAllMetadata(MDs);
1497 for (const auto &I : MDs)
1498 Dst.setMetadata(I.first, MapMetadata(I.second, ValueMap, RF_MoveDistinctMDs,
1499 &TypeMap, &ValMaterializer));
1501 // Splice the body of the source function into the dest function.
1502 Dst.getBasicBlockList().splice(Dst.end(), Src.getBasicBlockList());
1504 // At this point, all of the instructions and values of the function are now
1505 // copied over. The only problem is that they are still referencing values in
1506 // the Source function as operands. Loop through all of the operands of the
1507 // functions and patch them up to point to the local versions.
1508 for (BasicBlock &BB : Dst)
1509 for (Instruction &I : BB)
1510 RemapInstruction(&I, ValueMap,
1511 RF_IgnoreMissingEntries | RF_MoveDistinctMDs, &TypeMap,
1514 // There is no need to map the arguments anymore.
1515 for (Argument &Arg : Src.args())
1516 ValueMap.erase(&Arg);
1518 Src.dematerialize();
1522 void ModuleLinker::linkAliasBody(GlobalAlias &Dst, GlobalAlias &Src) {
1523 Constant *Aliasee = Src.getAliasee();
1524 Constant *Val = MapValue(Aliasee, ValueMap, RF_MoveDistinctMDs, &TypeMap,
1526 Dst.setAliasee(Val);
1529 bool ModuleLinker::linkGlobalValueBody(GlobalValue &Dst, GlobalValue &Src) {
1530 if (const Comdat *SC = Src.getComdat()) {
1531 // To ensure that we don't generate an incomplete comdat group,
1532 // we must materialize and map in any other members that are not
1533 // yet materialized in Dst, which also ensures their definitions
1534 // are linked in. Otherwise, linkonce and other lazy linked GVs will
1535 // not be materialized if they aren't referenced.
1536 for (auto *SGV : ComdatMembers[SC]) {
1537 auto *DGV = cast_or_null<GlobalValue>(ValueMap[SGV]);
1538 if (DGV && !DGV->isDeclaration())
1540 MapValue(SGV, ValueMap, RF_MoveDistinctMDs, &TypeMap, &ValMaterializer);
1543 if (shouldInternalizeLinkedSymbols())
1544 if (auto *DGV = dyn_cast<GlobalValue>(&Dst))
1545 DGV->setLinkage(GlobalValue::InternalLinkage);
1546 if (auto *F = dyn_cast<Function>(&Src))
1547 return linkFunctionBody(cast<Function>(Dst), *F);
1548 if (auto *GVar = dyn_cast<GlobalVariable>(&Src)) {
1549 linkGlobalInit(cast<GlobalVariable>(Dst), *GVar);
1552 linkAliasBody(cast<GlobalAlias>(Dst), cast<GlobalAlias>(Src));
1556 /// Insert all of the named MDNodes in Src into the Dest module.
1557 void ModuleLinker::linkNamedMDNodes() {
1558 const NamedMDNode *SrcModFlags = SrcM.getModuleFlagsMetadata();
1559 for (const NamedMDNode &NMD : SrcM.named_metadata()) {
1560 // Don't link module flags here. Do them separately.
1561 if (&NMD == SrcModFlags)
1563 NamedMDNode *DestNMD = DstM.getOrInsertNamedMetadata(NMD.getName());
1564 // Add Src elements into Dest node.
1565 for (const MDNode *op : NMD.operands())
1566 DestNMD->addOperand(MapMetadata(
1567 op, ValueMap, RF_MoveDistinctMDs | RF_NullMapMissingGlobalValues,
1568 &TypeMap, &ValMaterializer));
1572 /// Merge the linker flags in Src into the Dest module.
1573 bool ModuleLinker::linkModuleFlagsMetadata() {
1574 // If the source module has no module flags, we are done.
1575 const NamedMDNode *SrcModFlags = SrcM.getModuleFlagsMetadata();
1579 // If the destination module doesn't have module flags yet, then just copy
1580 // over the source module's flags.
1581 NamedMDNode *DstModFlags = DstM.getOrInsertModuleFlagsMetadata();
1582 if (DstModFlags->getNumOperands() == 0) {
1583 for (unsigned I = 0, E = SrcModFlags->getNumOperands(); I != E; ++I)
1584 DstModFlags->addOperand(SrcModFlags->getOperand(I));
1589 // First build a map of the existing module flags and requirements.
1590 DenseMap<MDString *, std::pair<MDNode *, unsigned>> Flags;
1591 SmallSetVector<MDNode *, 16> Requirements;
1592 for (unsigned I = 0, E = DstModFlags->getNumOperands(); I != E; ++I) {
1593 MDNode *Op = DstModFlags->getOperand(I);
1594 ConstantInt *Behavior = mdconst::extract<ConstantInt>(Op->getOperand(0));
1595 MDString *ID = cast<MDString>(Op->getOperand(1));
1597 if (Behavior->getZExtValue() == Module::Require) {
1598 Requirements.insert(cast<MDNode>(Op->getOperand(2)));
1600 Flags[ID] = std::make_pair(Op, I);
1604 // Merge in the flags from the source module, and also collect its set of
1606 bool HasErr = false;
1607 for (unsigned I = 0, E = SrcModFlags->getNumOperands(); I != E; ++I) {
1608 MDNode *SrcOp = SrcModFlags->getOperand(I);
1609 ConstantInt *SrcBehavior =
1610 mdconst::extract<ConstantInt>(SrcOp->getOperand(0));
1611 MDString *ID = cast<MDString>(SrcOp->getOperand(1));
1614 std::tie(DstOp, DstIndex) = Flags.lookup(ID);
1615 unsigned SrcBehaviorValue = SrcBehavior->getZExtValue();
1617 // If this is a requirement, add it and continue.
1618 if (SrcBehaviorValue == Module::Require) {
1619 // If the destination module does not already have this requirement, add
1621 if (Requirements.insert(cast<MDNode>(SrcOp->getOperand(2)))) {
1622 DstModFlags->addOperand(SrcOp);
1627 // If there is no existing flag with this ID, just add it.
1629 Flags[ID] = std::make_pair(SrcOp, DstModFlags->getNumOperands());
1630 DstModFlags->addOperand(SrcOp);
1634 // Otherwise, perform a merge.
1635 ConstantInt *DstBehavior =
1636 mdconst::extract<ConstantInt>(DstOp->getOperand(0));
1637 unsigned DstBehaviorValue = DstBehavior->getZExtValue();
1639 // If either flag has override behavior, handle it first.
1640 if (DstBehaviorValue == Module::Override) {
1641 // Diagnose inconsistent flags which both have override behavior.
1642 if (SrcBehaviorValue == Module::Override &&
1643 SrcOp->getOperand(2) != DstOp->getOperand(2)) {
1644 HasErr |= emitError("linking module flags '" + ID->getString() +
1645 "': IDs have conflicting override values");
1648 } else if (SrcBehaviorValue == Module::Override) {
1649 // Update the destination flag to that of the source.
1650 DstModFlags->setOperand(DstIndex, SrcOp);
1651 Flags[ID].first = SrcOp;
1655 // Diagnose inconsistent merge behavior types.
1656 if (SrcBehaviorValue != DstBehaviorValue) {
1657 HasErr |= emitError("linking module flags '" + ID->getString() +
1658 "': IDs have conflicting behaviors");
1662 auto replaceDstValue = [&](MDNode *New) {
1663 Metadata *FlagOps[] = {DstOp->getOperand(0), ID, New};
1664 MDNode *Flag = MDNode::get(DstM.getContext(), FlagOps);
1665 DstModFlags->setOperand(DstIndex, Flag);
1666 Flags[ID].first = Flag;
1669 // Perform the merge for standard behavior types.
1670 switch (SrcBehaviorValue) {
1671 case Module::Require:
1672 case Module::Override:
1673 llvm_unreachable("not possible");
1674 case Module::Error: {
1675 // Emit an error if the values differ.
1676 if (SrcOp->getOperand(2) != DstOp->getOperand(2)) {
1677 HasErr |= emitError("linking module flags '" + ID->getString() +
1678 "': IDs have conflicting values");
1682 case Module::Warning: {
1683 // Emit a warning if the values differ.
1684 if (SrcOp->getOperand(2) != DstOp->getOperand(2)) {
1685 emitWarning("linking module flags '" + ID->getString() +
1686 "': IDs have conflicting values");
1690 case Module::Append: {
1691 MDNode *DstValue = cast<MDNode>(DstOp->getOperand(2));
1692 MDNode *SrcValue = cast<MDNode>(SrcOp->getOperand(2));
1693 SmallVector<Metadata *, 8> MDs;
1694 MDs.reserve(DstValue->getNumOperands() + SrcValue->getNumOperands());
1695 MDs.append(DstValue->op_begin(), DstValue->op_end());
1696 MDs.append(SrcValue->op_begin(), SrcValue->op_end());
1698 replaceDstValue(MDNode::get(DstM.getContext(), MDs));
1701 case Module::AppendUnique: {
1702 SmallSetVector<Metadata *, 16> Elts;
1703 MDNode *DstValue = cast<MDNode>(DstOp->getOperand(2));
1704 MDNode *SrcValue = cast<MDNode>(SrcOp->getOperand(2));
1705 Elts.insert(DstValue->op_begin(), DstValue->op_end());
1706 Elts.insert(SrcValue->op_begin(), SrcValue->op_end());
1708 replaceDstValue(MDNode::get(DstM.getContext(),
1709 makeArrayRef(Elts.begin(), Elts.end())));
1715 // Check all of the requirements.
1716 for (unsigned I = 0, E = Requirements.size(); I != E; ++I) {
1717 MDNode *Requirement = Requirements[I];
1718 MDString *Flag = cast<MDString>(Requirement->getOperand(0));
1719 Metadata *ReqValue = Requirement->getOperand(1);
1721 MDNode *Op = Flags[Flag].first;
1722 if (!Op || Op->getOperand(2) != ReqValue) {
1723 HasErr |= emitError("linking module flags '" + Flag->getString() +
1724 "': does not have the required value");
1732 // This function returns true if the triples match.
1733 static bool triplesMatch(const Triple &T0, const Triple &T1) {
1734 // If vendor is apple, ignore the version number.
1735 if (T0.getVendor() == Triple::Apple)
1736 return T0.getArch() == T1.getArch() && T0.getSubArch() == T1.getSubArch() &&
1737 T0.getVendor() == T1.getVendor() && T0.getOS() == T1.getOS();
1742 // This function returns the merged triple.
1743 static std::string mergeTriples(const Triple &SrcTriple,
1744 const Triple &DstTriple) {
1745 // If vendor is apple, pick the triple with the larger version number.
1746 if (SrcTriple.getVendor() == Triple::Apple)
1747 if (DstTriple.isOSVersionLT(SrcTriple))
1748 return SrcTriple.str();
1750 return DstTriple.str();
1753 bool ModuleLinker::linkIfNeeded(GlobalValue &GV) {
1754 GlobalValue *DGV = getLinkedToGlobal(&GV);
1756 if (shouldLinkOnlyNeeded() && !(DGV && DGV->isDeclaration()))
1759 if (DGV && !GV.hasLocalLinkage() && !GV.hasAppendingLinkage()) {
1760 auto *DGVar = dyn_cast<GlobalVariable>(DGV);
1761 auto *SGVar = dyn_cast<GlobalVariable>(&GV);
1762 if (DGVar && SGVar) {
1763 if (DGVar->isDeclaration() && SGVar->isDeclaration() &&
1764 (!DGVar->isConstant() || !SGVar->isConstant())) {
1765 DGVar->setConstant(false);
1766 SGVar->setConstant(false);
1768 if (DGVar->hasCommonLinkage() && SGVar->hasCommonLinkage()) {
1769 unsigned Align = std::max(DGVar->getAlignment(), SGVar->getAlignment());
1770 SGVar->setAlignment(Align);
1771 DGVar->setAlignment(Align);
1775 GlobalValue::VisibilityTypes Visibility =
1776 getMinVisibility(DGV->getVisibility(), GV.getVisibility());
1777 DGV->setVisibility(Visibility);
1778 GV.setVisibility(Visibility);
1780 bool HasUnnamedAddr = GV.hasUnnamedAddr() && DGV->hasUnnamedAddr();
1781 DGV->setUnnamedAddr(HasUnnamedAddr);
1782 GV.setUnnamedAddr(HasUnnamedAddr);
1785 // Don't want to append to global_ctors list, for example, when we
1786 // are importing for ThinLTO, otherwise the global ctors and dtors
1787 // get executed multiple times for local variables (the latter causing
1789 if (GV.hasAppendingLinkage() && isPerformingImport())
1792 if (isPerformingImport() && !doImportAsDefinition(&GV))
1795 if (!DGV && !shouldOverrideFromSrc() &&
1796 (GV.hasLocalLinkage() || GV.hasLinkOnceLinkage() ||
1797 GV.hasAvailableExternallyLinkage()))
1800 if (const Comdat *SC = GV.getComdat()) {
1802 Comdat::SelectionKind SK;
1803 std::tie(SK, LinkFromSrc) = ComdatsChosen[SC];
1805 ValuesToLink.insert(&GV);
1809 bool LinkFromSrc = true;
1810 if (DGV && shouldLinkFromSource(LinkFromSrc, *DGV, GV))
1813 ValuesToLink.insert(&GV);
1817 bool ModuleLinker::run() {
1818 // Inherit the target data from the source module if the destination module
1819 // doesn't have one already.
1820 if (DstM.getDataLayout().isDefault())
1821 DstM.setDataLayout(SrcM.getDataLayout());
1823 if (SrcM.getDataLayout() != DstM.getDataLayout()) {
1824 emitWarning("Linking two modules of different data layouts: '" +
1825 SrcM.getModuleIdentifier() + "' is '" +
1826 SrcM.getDataLayoutStr() + "' whereas '" +
1827 DstM.getModuleIdentifier() + "' is '" +
1828 DstM.getDataLayoutStr() + "'\n");
1831 // Copy the target triple from the source to dest if the dest's is empty.
1832 if (DstM.getTargetTriple().empty() && !SrcM.getTargetTriple().empty())
1833 DstM.setTargetTriple(SrcM.getTargetTriple());
1835 Triple SrcTriple(SrcM.getTargetTriple()), DstTriple(DstM.getTargetTriple());
1837 if (!SrcM.getTargetTriple().empty() && !triplesMatch(SrcTriple, DstTriple))
1838 emitWarning("Linking two modules of different target triples: " +
1839 SrcM.getModuleIdentifier() + "' is '" + SrcM.getTargetTriple() +
1840 "' whereas '" + DstM.getModuleIdentifier() + "' is '" +
1841 DstM.getTargetTriple() + "'\n");
1843 DstM.setTargetTriple(mergeTriples(SrcTriple, DstTriple));
1845 // Append the module inline asm string.
1846 if (!SrcM.getModuleInlineAsm().empty()) {
1847 if (DstM.getModuleInlineAsm().empty())
1848 DstM.setModuleInlineAsm(SrcM.getModuleInlineAsm());
1850 DstM.setModuleInlineAsm(DstM.getModuleInlineAsm() + "\n" +
1851 SrcM.getModuleInlineAsm());
1854 // Loop over all of the linked values to compute type mappings.
1855 computeTypeMapping();
1857 ComdatsChosen.clear();
1858 for (const auto &SMEC : SrcM.getComdatSymbolTable()) {
1859 const Comdat &C = SMEC.getValue();
1860 if (ComdatsChosen.count(&C))
1862 Comdat::SelectionKind SK;
1864 if (getComdatResult(&C, SK, LinkFromSrc))
1866 ComdatsChosen[&C] = std::make_pair(SK, LinkFromSrc);
1869 // Upgrade mismatched global arrays.
1870 upgradeMismatchedGlobals();
1872 for (GlobalVariable &GV : SrcM.globals())
1873 if (const Comdat *SC = GV.getComdat())
1874 ComdatMembers[SC].push_back(&GV);
1876 for (Function &SF : SrcM)
1877 if (const Comdat *SC = SF.getComdat())
1878 ComdatMembers[SC].push_back(&SF);
1880 for (GlobalAlias &GA : SrcM.aliases())
1881 if (const Comdat *SC = GA.getComdat())
1882 ComdatMembers[SC].push_back(&GA);
1884 // Insert all of the globals in src into the DstM module... without linking
1885 // initializers (which could refer to functions not yet mapped over).
1886 for (GlobalVariable &GV : SrcM.globals())
1887 if (linkIfNeeded(GV))
1890 for (Function &SF : SrcM)
1891 if (linkIfNeeded(SF))
1894 for (GlobalAlias &GA : SrcM.aliases())
1895 if (linkIfNeeded(GA))
1898 for (GlobalValue *GV : ValuesToLink) {
1899 MapValue(GV, ValueMap, RF_MoveDistinctMDs, &TypeMap, &ValMaterializer);
1904 // Note that we are done linking global value bodies. This prevents
1905 // metadata linking from creating new references.
1906 DoneLinkingBodies = true;
1908 // Remap all of the named MDNodes in Src into the DstM module. We do this
1909 // after linking GlobalValues so that MDNodes that reference GlobalValues
1910 // are properly remapped.
1913 // Merge the module flags into the DstM module.
1914 if (linkModuleFlagsMetadata())
1920 Linker::StructTypeKeyInfo::KeyTy::KeyTy(ArrayRef<Type *> E, bool P)
1921 : ETypes(E), IsPacked(P) {}
1923 Linker::StructTypeKeyInfo::KeyTy::KeyTy(const StructType *ST)
1924 : ETypes(ST->elements()), IsPacked(ST->isPacked()) {}
1926 bool Linker::StructTypeKeyInfo::KeyTy::operator==(const KeyTy &That) const {
1927 if (IsPacked != That.IsPacked)
1929 if (ETypes != That.ETypes)
1934 bool Linker::StructTypeKeyInfo::KeyTy::operator!=(const KeyTy &That) const {
1935 return !this->operator==(That);
1938 StructType *Linker::StructTypeKeyInfo::getEmptyKey() {
1939 return DenseMapInfo<StructType *>::getEmptyKey();
1942 StructType *Linker::StructTypeKeyInfo::getTombstoneKey() {
1943 return DenseMapInfo<StructType *>::getTombstoneKey();
1946 unsigned Linker::StructTypeKeyInfo::getHashValue(const KeyTy &Key) {
1947 return hash_combine(hash_combine_range(Key.ETypes.begin(), Key.ETypes.end()),
1951 unsigned Linker::StructTypeKeyInfo::getHashValue(const StructType *ST) {
1952 return getHashValue(KeyTy(ST));
1955 bool Linker::StructTypeKeyInfo::isEqual(const KeyTy &LHS,
1956 const StructType *RHS) {
1957 if (RHS == getEmptyKey() || RHS == getTombstoneKey())
1959 return LHS == KeyTy(RHS);
1962 bool Linker::StructTypeKeyInfo::isEqual(const StructType *LHS,
1963 const StructType *RHS) {
1964 if (RHS == getEmptyKey())
1965 return LHS == getEmptyKey();
1967 if (RHS == getTombstoneKey())
1968 return LHS == getTombstoneKey();
1970 return KeyTy(LHS) == KeyTy(RHS);
1973 void Linker::IdentifiedStructTypeSet::addNonOpaque(StructType *Ty) {
1974 assert(!Ty->isOpaque());
1975 NonOpaqueStructTypes.insert(Ty);
1978 void Linker::IdentifiedStructTypeSet::switchToNonOpaque(StructType *Ty) {
1979 assert(!Ty->isOpaque());
1980 NonOpaqueStructTypes.insert(Ty);
1981 bool Removed = OpaqueStructTypes.erase(Ty);
1986 void Linker::IdentifiedStructTypeSet::addOpaque(StructType *Ty) {
1987 assert(Ty->isOpaque());
1988 OpaqueStructTypes.insert(Ty);
1992 Linker::IdentifiedStructTypeSet::findNonOpaque(ArrayRef<Type *> ETypes,
1994 Linker::StructTypeKeyInfo::KeyTy Key(ETypes, IsPacked);
1995 auto I = NonOpaqueStructTypes.find_as(Key);
1996 if (I == NonOpaqueStructTypes.end())
2001 bool Linker::IdentifiedStructTypeSet::hasType(StructType *Ty) {
2003 return OpaqueStructTypes.count(Ty);
2004 auto I = NonOpaqueStructTypes.find(Ty);
2005 if (I == NonOpaqueStructTypes.end())
2010 Linker::Linker(Module &M, DiagnosticHandlerFunction DiagnosticHandler)
2011 : Composite(M), DiagnosticHandler(DiagnosticHandler) {
2012 TypeFinder StructTypes;
2013 StructTypes.run(M, true);
2014 for (StructType *Ty : StructTypes) {
2016 IdentifiedStructTypes.addOpaque(Ty);
2018 IdentifiedStructTypes.addNonOpaque(Ty);
2022 Linker::Linker(Module &M)
2023 : Linker(M, [this](const DiagnosticInfo &DI) {
2024 Composite.getContext().diagnose(DI);
2027 bool Linker::linkInModule(Module &Src, unsigned Flags,
2028 const FunctionInfoIndex *Index,
2029 DenseSet<const GlobalValue *> *FunctionsToImport) {
2030 ModuleLinker TheLinker(Composite, IdentifiedStructTypes, Src,
2031 DiagnosticHandler, Flags, Index, FunctionsToImport);
2032 bool RetCode = TheLinker.run();
2033 Composite.dropTriviallyDeadConstantArrays();
2037 //===----------------------------------------------------------------------===//
2038 // LinkModules entrypoint.
2039 //===----------------------------------------------------------------------===//
2041 /// This function links two modules together, with the resulting Dest module
2042 /// modified to be the composite of the two input modules. If an error occurs,
2043 /// true is returned and ErrorMsg (if not null) is set to indicate the problem.
2044 /// Upon failure, the Dest module could be in a modified state, and shouldn't be
2045 /// relied on to be consistent.
2046 bool Linker::linkModules(Module &Dest, Module &Src,
2047 DiagnosticHandlerFunction DiagnosticHandler,
2049 Linker L(Dest, DiagnosticHandler);
2050 return L.linkInModule(Src, Flags);
2053 bool Linker::linkModules(Module &Dest, Module &Src, unsigned Flags) {
2055 return L.linkInModule(Src, Flags);
2058 //===----------------------------------------------------------------------===//
2060 //===----------------------------------------------------------------------===//
2062 LLVMBool LLVMLinkModules(LLVMModuleRef Dest, LLVMModuleRef Src,
2063 LLVMLinkerMode Unused, char **OutMessages) {
2064 Module *D = unwrap(Dest);
2065 std::string Message;
2066 raw_string_ostream Stream(Message);
2067 DiagnosticPrinterRawOStream DP(Stream);
2069 LLVMBool Result = Linker::linkModules(
2070 *D, *unwrap(Src), [&](const DiagnosticInfo &DI) { DI.print(DP); });
2072 if (OutMessages && Result) {
2074 *OutMessages = strdup(Message.c_str());