1 //===- lib/Linker/IRMover.cpp ---------------------------------------------===//
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7 //===----------------------------------------------------------------------===//
9 #include "llvm/Linker/IRMover.h"
10 #include "LinkDiagnosticInfo.h"
11 #include "llvm/ADT/SetVector.h"
12 #include "llvm/ADT/SmallString.h"
13 #include "llvm/ADT/Triple.h"
14 #include "llvm/IR/Constants.h"
15 #include "llvm/IR/DebugInfo.h"
16 #include "llvm/IR/DiagnosticPrinter.h"
17 #include "llvm/IR/GVMaterializer.h"
18 #include "llvm/IR/Intrinsics.h"
19 #include "llvm/IR/TypeFinder.h"
20 #include "llvm/Support/Error.h"
21 #include "llvm/Transforms/Utils/Cloning.h"
25 //===----------------------------------------------------------------------===//
26 // TypeMap implementation.
27 //===----------------------------------------------------------------------===//
30 class TypeMapTy : public ValueMapTypeRemapper {
31 /// This is a mapping from a source type to a destination type to use.
32 DenseMap<Type *, Type *> MappedTypes;
34 /// When checking to see if two subgraphs are isomorphic, we speculatively
35 /// add types to MappedTypes, but keep track of them here in case we need to
37 SmallVector<Type *, 16> SpeculativeTypes;
39 SmallVector<StructType *, 16> SpeculativeDstOpaqueTypes;
41 /// This is a list of non-opaque structs in the source module that are mapped
42 /// to an opaque struct in the destination module.
43 SmallVector<StructType *, 16> SrcDefinitionsToResolve;
45 /// This is the set of opaque types in the destination modules who are
46 /// getting a body from the source module.
47 SmallPtrSet<StructType *, 16> DstResolvedOpaqueTypes;
50 TypeMapTy(IRMover::IdentifiedStructTypeSet &DstStructTypesSet)
51 : DstStructTypesSet(DstStructTypesSet) {}
53 IRMover::IdentifiedStructTypeSet &DstStructTypesSet;
54 /// Indicate that the specified type in the destination module is conceptually
55 /// equivalent to the specified type in the source module.
56 void addTypeMapping(Type *DstTy, Type *SrcTy);
58 /// Produce a body for an opaque type in the dest module from a type
59 /// definition in the source module.
60 void linkDefinedTypeBodies();
62 /// Return the mapped type to use for the specified input type from the
64 Type *get(Type *SrcTy);
65 Type *get(Type *SrcTy, SmallPtrSet<StructType *, 8> &Visited);
67 void finishType(StructType *DTy, StructType *STy, ArrayRef<Type *> ETypes);
69 FunctionType *get(FunctionType *T) {
70 return cast<FunctionType>(get((Type *)T));
74 Type *remapType(Type *SrcTy) override { return get(SrcTy); }
76 bool areTypesIsomorphic(Type *DstTy, Type *SrcTy);
80 void TypeMapTy::addTypeMapping(Type *DstTy, Type *SrcTy) {
81 assert(SpeculativeTypes.empty());
82 assert(SpeculativeDstOpaqueTypes.empty());
84 // Check to see if these types are recursively isomorphic and establish a
85 // mapping between them if so.
86 if (!areTypesIsomorphic(DstTy, SrcTy)) {
87 // Oops, they aren't isomorphic. Just discard this request by rolling out
88 // any speculative mappings we've established.
89 for (Type *Ty : SpeculativeTypes)
90 MappedTypes.erase(Ty);
92 SrcDefinitionsToResolve.resize(SrcDefinitionsToResolve.size() -
93 SpeculativeDstOpaqueTypes.size());
94 for (StructType *Ty : SpeculativeDstOpaqueTypes)
95 DstResolvedOpaqueTypes.erase(Ty);
97 // SrcTy and DstTy are recursively ismorphic. We clear names of SrcTy
98 // and all its descendants to lower amount of renaming in LLVM context
99 // Renaming occurs because we load all source modules to the same context
100 // and declaration with existing name gets renamed (i.e Foo -> Foo.42).
101 // As a result we may get several different types in the destination
102 // module, which are in fact the same.
103 for (Type *Ty : SpeculativeTypes)
104 if (auto *STy = dyn_cast<StructType>(Ty))
108 SpeculativeTypes.clear();
109 SpeculativeDstOpaqueTypes.clear();
112 /// Recursively walk this pair of types, returning true if they are isomorphic,
113 /// false if they are not.
114 bool TypeMapTy::areTypesIsomorphic(Type *DstTy, Type *SrcTy) {
115 // Two types with differing kinds are clearly not isomorphic.
116 if (DstTy->getTypeID() != SrcTy->getTypeID())
119 // If we have an entry in the MappedTypes table, then we have our answer.
120 Type *&Entry = MappedTypes[SrcTy];
122 return Entry == DstTy;
124 // Two identical types are clearly isomorphic. Remember this
125 // non-speculatively.
126 if (DstTy == SrcTy) {
131 // Okay, we have two types with identical kinds that we haven't seen before.
133 // If this is an opaque struct type, special case it.
134 if (StructType *SSTy = dyn_cast<StructType>(SrcTy)) {
135 // Mapping an opaque type to any struct, just keep the dest struct.
136 if (SSTy->isOpaque()) {
138 SpeculativeTypes.push_back(SrcTy);
142 // Mapping a non-opaque source type to an opaque dest. If this is the first
143 // type that we're mapping onto this destination type then we succeed. Keep
144 // the dest, but fill it in later. If this is the second (different) type
145 // that we're trying to map onto the same opaque type then we fail.
146 if (cast<StructType>(DstTy)->isOpaque()) {
147 // We can only map one source type onto the opaque destination type.
148 if (!DstResolvedOpaqueTypes.insert(cast<StructType>(DstTy)).second)
150 SrcDefinitionsToResolve.push_back(SSTy);
151 SpeculativeTypes.push_back(SrcTy);
152 SpeculativeDstOpaqueTypes.push_back(cast<StructType>(DstTy));
158 // If the number of subtypes disagree between the two types, then we fail.
159 if (SrcTy->getNumContainedTypes() != DstTy->getNumContainedTypes())
162 // Fail if any of the extra properties (e.g. array size) of the type disagree.
163 if (isa<IntegerType>(DstTy))
164 return false; // bitwidth disagrees.
165 if (PointerType *PT = dyn_cast<PointerType>(DstTy)) {
166 if (PT->getAddressSpace() != cast<PointerType>(SrcTy)->getAddressSpace())
168 } else if (FunctionType *FT = dyn_cast<FunctionType>(DstTy)) {
169 if (FT->isVarArg() != cast<FunctionType>(SrcTy)->isVarArg())
171 } else if (StructType *DSTy = dyn_cast<StructType>(DstTy)) {
172 StructType *SSTy = cast<StructType>(SrcTy);
173 if (DSTy->isLiteral() != SSTy->isLiteral() ||
174 DSTy->isPacked() != SSTy->isPacked())
176 } else if (auto *DSeqTy = dyn_cast<SequentialType>(DstTy)) {
177 if (DSeqTy->getNumElements() !=
178 cast<SequentialType>(SrcTy)->getNumElements())
182 // Otherwise, we speculate that these two types will line up and recursively
183 // check the subelements.
185 SpeculativeTypes.push_back(SrcTy);
187 for (unsigned I = 0, E = SrcTy->getNumContainedTypes(); I != E; ++I)
188 if (!areTypesIsomorphic(DstTy->getContainedType(I),
189 SrcTy->getContainedType(I)))
192 // If everything seems to have lined up, then everything is great.
196 void TypeMapTy::linkDefinedTypeBodies() {
197 SmallVector<Type *, 16> Elements;
198 for (StructType *SrcSTy : SrcDefinitionsToResolve) {
199 StructType *DstSTy = cast<StructType>(MappedTypes[SrcSTy]);
200 assert(DstSTy->isOpaque());
202 // Map the body of the source type over to a new body for the dest type.
203 Elements.resize(SrcSTy->getNumElements());
204 for (unsigned I = 0, E = Elements.size(); I != E; ++I)
205 Elements[I] = get(SrcSTy->getElementType(I));
207 DstSTy->setBody(Elements, SrcSTy->isPacked());
208 DstStructTypesSet.switchToNonOpaque(DstSTy);
210 SrcDefinitionsToResolve.clear();
211 DstResolvedOpaqueTypes.clear();
214 void TypeMapTy::finishType(StructType *DTy, StructType *STy,
215 ArrayRef<Type *> ETypes) {
216 DTy->setBody(ETypes, STy->isPacked());
219 if (STy->hasName()) {
220 SmallString<16> TmpName = STy->getName();
222 DTy->setName(TmpName);
225 DstStructTypesSet.addNonOpaque(DTy);
228 Type *TypeMapTy::get(Type *Ty) {
229 SmallPtrSet<StructType *, 8> Visited;
230 return get(Ty, Visited);
233 Type *TypeMapTy::get(Type *Ty, SmallPtrSet<StructType *, 8> &Visited) {
234 // If we already have an entry for this type, return it.
235 Type **Entry = &MappedTypes[Ty];
239 // These are types that LLVM itself will unique.
240 bool IsUniqued = !isa<StructType>(Ty) || cast<StructType>(Ty)->isLiteral();
243 StructType *STy = cast<StructType>(Ty);
244 // This is actually a type from the destination module, this can be reached
245 // when this type is loaded in another module, added to DstStructTypesSet,
246 // and then we reach the same type in another module where it has not been
247 // added to MappedTypes. (PR37684)
248 if (STy->getContext().isODRUniquingDebugTypes() && !STy->isOpaque() &&
249 DstStructTypesSet.hasType(STy))
253 for (auto &Pair : MappedTypes) {
254 assert(!(Pair.first != Ty && Pair.second == Ty) &&
255 "mapping to a source type");
259 if (!Visited.insert(STy).second) {
260 StructType *DTy = StructType::create(Ty->getContext());
265 // If this is not a recursive type, then just map all of the elements and
266 // then rebuild the type from inside out.
267 SmallVector<Type *, 4> ElementTypes;
269 // If there are no element types to map, then the type is itself. This is
270 // true for the anonymous {} struct, things like 'float', integers, etc.
271 if (Ty->getNumContainedTypes() == 0 && IsUniqued)
274 // Remap all of the elements, keeping track of whether any of them change.
275 bool AnyChange = false;
276 ElementTypes.resize(Ty->getNumContainedTypes());
277 for (unsigned I = 0, E = Ty->getNumContainedTypes(); I != E; ++I) {
278 ElementTypes[I] = get(Ty->getContainedType(I), Visited);
279 AnyChange |= ElementTypes[I] != Ty->getContainedType(I);
282 // If we found our type while recursively processing stuff, just use it.
283 Entry = &MappedTypes[Ty];
285 if (auto *DTy = dyn_cast<StructType>(*Entry)) {
286 if (DTy->isOpaque()) {
287 auto *STy = cast<StructType>(Ty);
288 finishType(DTy, STy, ElementTypes);
294 // If all of the element types mapped directly over and the type is not
295 // a named struct, then the type is usable as-is.
296 if (!AnyChange && IsUniqued)
299 // Otherwise, rebuild a modified type.
300 switch (Ty->getTypeID()) {
302 llvm_unreachable("unknown derived type to remap");
303 case Type::ArrayTyID:
304 return *Entry = ArrayType::get(ElementTypes[0],
305 cast<ArrayType>(Ty)->getNumElements());
306 case Type::VectorTyID:
307 return *Entry = VectorType::get(ElementTypes[0],
308 cast<VectorType>(Ty)->getNumElements());
309 case Type::PointerTyID:
310 return *Entry = PointerType::get(ElementTypes[0],
311 cast<PointerType>(Ty)->getAddressSpace());
312 case Type::FunctionTyID:
313 return *Entry = FunctionType::get(ElementTypes[0],
314 makeArrayRef(ElementTypes).slice(1),
315 cast<FunctionType>(Ty)->isVarArg());
316 case Type::StructTyID: {
317 auto *STy = cast<StructType>(Ty);
318 bool IsPacked = STy->isPacked();
320 return *Entry = StructType::get(Ty->getContext(), ElementTypes, IsPacked);
322 // If the type is opaque, we can just use it directly.
323 if (STy->isOpaque()) {
324 DstStructTypesSet.addOpaque(STy);
328 if (StructType *OldT =
329 DstStructTypesSet.findNonOpaque(ElementTypes, IsPacked)) {
331 return *Entry = OldT;
335 DstStructTypesSet.addNonOpaque(STy);
339 StructType *DTy = StructType::create(Ty->getContext());
340 finishType(DTy, STy, ElementTypes);
346 LinkDiagnosticInfo::LinkDiagnosticInfo(DiagnosticSeverity Severity,
348 : DiagnosticInfo(DK_Linker, Severity), Msg(Msg) {}
349 void LinkDiagnosticInfo::print(DiagnosticPrinter &DP) const { DP << Msg; }
351 //===----------------------------------------------------------------------===//
352 // IRLinker implementation.
353 //===----------------------------------------------------------------------===//
358 /// Creates prototypes for functions that are lazily linked on the fly. This
359 /// speeds up linking for modules with many/ lazily linked functions of which
361 class GlobalValueMaterializer final : public ValueMaterializer {
362 IRLinker &TheIRLinker;
365 GlobalValueMaterializer(IRLinker &TheIRLinker) : TheIRLinker(TheIRLinker) {}
366 Value *materialize(Value *V) override;
369 class LocalValueMaterializer final : public ValueMaterializer {
370 IRLinker &TheIRLinker;
373 LocalValueMaterializer(IRLinker &TheIRLinker) : TheIRLinker(TheIRLinker) {}
374 Value *materialize(Value *V) override;
377 /// Type of the Metadata map in \a ValueToValueMapTy.
378 typedef DenseMap<const Metadata *, TrackingMDRef> MDMapT;
380 /// This is responsible for keeping track of the state used for moving data
381 /// from SrcM to DstM.
384 std::unique_ptr<Module> SrcM;
386 /// See IRMover::move().
387 std::function<void(GlobalValue &, IRMover::ValueAdder)> AddLazyFor;
390 GlobalValueMaterializer GValMaterializer;
391 LocalValueMaterializer LValMaterializer;
393 /// A metadata map that's shared between IRLinker instances.
396 /// Mapping of values from what they used to be in Src, to what they are now
397 /// in DstM. ValueToValueMapTy is a ValueMap, which involves some overhead
398 /// due to the use of Value handles which the Linker doesn't actually need,
399 /// but this allows us to reuse the ValueMapper code.
400 ValueToValueMapTy ValueMap;
401 ValueToValueMapTy IndirectSymbolValueMap;
403 DenseSet<GlobalValue *> ValuesToLink;
404 std::vector<GlobalValue *> Worklist;
405 std::vector<std::pair<GlobalValue *, Value*>> RAUWWorklist;
407 void maybeAdd(GlobalValue *GV) {
408 if (ValuesToLink.insert(GV).second)
409 Worklist.push_back(GV);
412 /// Whether we are importing globals for ThinLTO, as opposed to linking the
413 /// source module. If this flag is set, it means that we can rely on some
414 /// other object file to define any non-GlobalValue entities defined by the
415 /// source module. This currently causes us to not link retained types in
416 /// debug info metadata and module inline asm.
417 bool IsPerformingImport;
419 /// Set to true when all global value body linking is complete (including
420 /// lazy linking). Used to prevent metadata linking from creating new
422 bool DoneLinkingBodies = false;
424 /// The Error encountered during materialization. We use an Optional here to
425 /// avoid needing to manage an unconsumed success value.
426 Optional<Error> FoundError;
427 void setError(Error E) {
429 FoundError = std::move(E);
432 /// Most of the errors produced by this module are inconvertible StringErrors.
433 /// This convenience function lets us return one of those more easily.
434 Error stringErr(const Twine &T) {
435 return make_error<StringError>(T, inconvertibleErrorCode());
438 /// Entry point for mapping values and alternate context for mapping aliases.
440 unsigned IndirectSymbolMCID;
442 /// Handles cloning of a global values from the source module into
443 /// the destination module, including setting the attributes and visibility.
444 GlobalValue *copyGlobalValueProto(const GlobalValue *SGV, bool ForDefinition);
446 void emitWarning(const Twine &Message) {
447 SrcM->getContext().diagnose(LinkDiagnosticInfo(DS_Warning, Message));
450 /// Given a global in the source module, return the global in the
451 /// destination module that is being linked to, if any.
452 GlobalValue *getLinkedToGlobal(const GlobalValue *SrcGV) {
453 // If the source has no name it can't link. If it has local linkage,
454 // there is no name match-up going on.
455 if (!SrcGV->hasName() || SrcGV->hasLocalLinkage())
458 // Otherwise see if we have a match in the destination module's symtab.
459 GlobalValue *DGV = DstM.getNamedValue(SrcGV->getName());
463 // If we found a global with the same name in the dest module, but it has
464 // internal linkage, we are really not doing any linkage here.
465 if (DGV->hasLocalLinkage())
468 // Otherwise, we do in fact link to the destination global.
472 void computeTypeMapping();
474 Expected<Constant *> linkAppendingVarProto(GlobalVariable *DstGV,
475 const GlobalVariable *SrcGV);
477 /// Given the GlobaValue \p SGV in the source module, and the matching
478 /// GlobalValue \p DGV (if any), return true if the linker will pull \p SGV
479 /// into the destination module.
481 /// Note this code may call the client-provided \p AddLazyFor.
482 bool shouldLink(GlobalValue *DGV, GlobalValue &SGV);
483 Expected<Constant *> linkGlobalValueProto(GlobalValue *GV,
484 bool ForIndirectSymbol);
486 Error linkModuleFlagsMetadata();
488 void linkGlobalVariable(GlobalVariable &Dst, GlobalVariable &Src);
489 Error linkFunctionBody(Function &Dst, Function &Src);
490 void linkIndirectSymbolBody(GlobalIndirectSymbol &Dst,
491 GlobalIndirectSymbol &Src);
492 Error linkGlobalValueBody(GlobalValue &Dst, GlobalValue &Src);
494 /// Replace all types in the source AttributeList with the
495 /// corresponding destination type.
496 AttributeList mapAttributeTypes(LLVMContext &C, AttributeList Attrs);
498 /// Functions that take care of cloning a specific global value type
499 /// into the destination module.
500 GlobalVariable *copyGlobalVariableProto(const GlobalVariable *SGVar);
501 Function *copyFunctionProto(const Function *SF);
502 GlobalValue *copyGlobalIndirectSymbolProto(const GlobalIndirectSymbol *SGIS);
504 /// Perform "replace all uses with" operations. These work items need to be
505 /// performed as part of materialization, but we postpone them to happen after
506 /// materialization is done. The materializer called by ValueMapper is not
507 /// expected to delete constants, as ValueMapper is holding pointers to some
508 /// of them, but constant destruction may be indirectly triggered by RAUW.
509 /// Hence, the need to move this out of the materialization call chain.
510 void flushRAUWWorklist();
512 /// When importing for ThinLTO, prevent importing of types listed on
513 /// the DICompileUnit that we don't need a copy of in the importing
515 void prepareCompileUnitsForImport();
516 void linkNamedMDNodes();
519 IRLinker(Module &DstM, MDMapT &SharedMDs,
520 IRMover::IdentifiedStructTypeSet &Set, std::unique_ptr<Module> SrcM,
521 ArrayRef<GlobalValue *> ValuesToLink,
522 std::function<void(GlobalValue &, IRMover::ValueAdder)> AddLazyFor,
523 bool IsPerformingImport)
524 : DstM(DstM), SrcM(std::move(SrcM)), AddLazyFor(std::move(AddLazyFor)),
525 TypeMap(Set), GValMaterializer(*this), LValMaterializer(*this),
526 SharedMDs(SharedMDs), IsPerformingImport(IsPerformingImport),
527 Mapper(ValueMap, RF_MoveDistinctMDs | RF_IgnoreMissingLocals, &TypeMap,
529 IndirectSymbolMCID(Mapper.registerAlternateMappingContext(
530 IndirectSymbolValueMap, &LValMaterializer)) {
531 ValueMap.getMDMap() = std::move(SharedMDs);
532 for (GlobalValue *GV : ValuesToLink)
534 if (IsPerformingImport)
535 prepareCompileUnitsForImport();
537 ~IRLinker() { SharedMDs = std::move(*ValueMap.getMDMap()); }
540 Value *materialize(Value *V, bool ForIndirectSymbol);
544 /// The LLVM SymbolTable class autorenames globals that conflict in the symbol
545 /// table. This is good for all clients except for us. Go through the trouble
546 /// to force this back.
547 static void forceRenaming(GlobalValue *GV, StringRef Name) {
548 // If the global doesn't force its name or if it already has the right name,
549 // there is nothing for us to do.
550 if (GV->hasLocalLinkage() || GV->getName() == Name)
553 Module *M = GV->getParent();
555 // If there is a conflict, rename the conflict.
556 if (GlobalValue *ConflictGV = M->getNamedValue(Name)) {
557 GV->takeName(ConflictGV);
558 ConflictGV->setName(Name); // This will cause ConflictGV to get renamed
559 assert(ConflictGV->getName() != Name && "forceRenaming didn't work");
561 GV->setName(Name); // Force the name back
565 Value *GlobalValueMaterializer::materialize(Value *SGV) {
566 return TheIRLinker.materialize(SGV, false);
569 Value *LocalValueMaterializer::materialize(Value *SGV) {
570 return TheIRLinker.materialize(SGV, true);
573 Value *IRLinker::materialize(Value *V, bool ForIndirectSymbol) {
574 auto *SGV = dyn_cast<GlobalValue>(V);
578 Expected<Constant *> NewProto = linkGlobalValueProto(SGV, ForIndirectSymbol);
580 setError(NewProto.takeError());
586 GlobalValue *New = dyn_cast<GlobalValue>(*NewProto);
590 // If we already created the body, just return.
591 if (auto *F = dyn_cast<Function>(New)) {
592 if (!F->isDeclaration())
594 } else if (auto *V = dyn_cast<GlobalVariable>(New)) {
595 if (V->hasInitializer() || V->hasAppendingLinkage())
598 auto *IS = cast<GlobalIndirectSymbol>(New);
599 if (IS->getIndirectSymbol())
603 // When linking a global for an indirect symbol, it will always be linked.
604 // However we need to check if it was not already scheduled to satisfy a
605 // reference from a regular global value initializer. We know if it has been
606 // schedule if the "New" GlobalValue that is mapped here for the indirect
607 // symbol is the same as the one already mapped. If there is an entry in the
608 // ValueMap but the value is different, it means that the value already had a
609 // definition in the destination module (linkonce for instance), but we need a
610 // new definition for the indirect symbol ("New" will be different.
611 if (ForIndirectSymbol && ValueMap.lookup(SGV) == New)
614 if (ForIndirectSymbol || shouldLink(New, *SGV))
615 setError(linkGlobalValueBody(*New, *SGV));
620 /// Loop through the global variables in the src module and merge them into the
622 GlobalVariable *IRLinker::copyGlobalVariableProto(const GlobalVariable *SGVar) {
623 // No linking to be performed or linking from the source: simply create an
624 // identical version of the symbol over in the dest module... the
625 // initializer will be filled in later by LinkGlobalInits.
626 GlobalVariable *NewDGV =
627 new GlobalVariable(DstM, TypeMap.get(SGVar->getValueType()),
628 SGVar->isConstant(), GlobalValue::ExternalLinkage,
629 /*init*/ nullptr, SGVar->getName(),
630 /*insertbefore*/ nullptr, SGVar->getThreadLocalMode(),
631 SGVar->getAddressSpace());
632 NewDGV->setAlignment(MaybeAlign(SGVar->getAlignment()));
633 NewDGV->copyAttributesFrom(SGVar);
637 AttributeList IRLinker::mapAttributeTypes(LLVMContext &C, AttributeList Attrs) {
638 for (unsigned i = 0; i < Attrs.getNumAttrSets(); ++i) {
639 if (Attrs.hasAttribute(i, Attribute::ByVal)) {
640 Type *Ty = Attrs.getAttribute(i, Attribute::ByVal).getValueAsType();
644 Attrs = Attrs.removeAttribute(C, i, Attribute::ByVal);
645 Attrs = Attrs.addAttribute(
646 C, i, Attribute::getWithByValType(C, TypeMap.get(Ty)));
652 /// Link the function in the source module into the destination module if
653 /// needed, setting up mapping information.
654 Function *IRLinker::copyFunctionProto(const Function *SF) {
655 // If there is no linkage to be performed or we are linking from the source,
657 auto *F = Function::Create(TypeMap.get(SF->getFunctionType()),
658 GlobalValue::ExternalLinkage,
659 SF->getAddressSpace(), SF->getName(), &DstM);
660 F->copyAttributesFrom(SF);
661 F->setAttributes(mapAttributeTypes(F->getContext(), F->getAttributes()));
665 /// Set up prototypes for any indirect symbols that come over from the source
668 IRLinker::copyGlobalIndirectSymbolProto(const GlobalIndirectSymbol *SGIS) {
669 // If there is no linkage to be performed or we're linking from the source,
671 auto *Ty = TypeMap.get(SGIS->getValueType());
672 GlobalIndirectSymbol *GIS;
673 if (isa<GlobalAlias>(SGIS))
674 GIS = GlobalAlias::create(Ty, SGIS->getAddressSpace(),
675 GlobalValue::ExternalLinkage, SGIS->getName(),
678 GIS = GlobalIFunc::create(Ty, SGIS->getAddressSpace(),
679 GlobalValue::ExternalLinkage, SGIS->getName(),
681 GIS->copyAttributesFrom(SGIS);
685 GlobalValue *IRLinker::copyGlobalValueProto(const GlobalValue *SGV,
686 bool ForDefinition) {
688 if (auto *SGVar = dyn_cast<GlobalVariable>(SGV)) {
689 NewGV = copyGlobalVariableProto(SGVar);
690 } else if (auto *SF = dyn_cast<Function>(SGV)) {
691 NewGV = copyFunctionProto(SF);
694 NewGV = copyGlobalIndirectSymbolProto(cast<GlobalIndirectSymbol>(SGV));
695 else if (SGV->getValueType()->isFunctionTy())
697 Function::Create(cast<FunctionType>(TypeMap.get(SGV->getValueType())),
698 GlobalValue::ExternalLinkage, SGV->getAddressSpace(),
699 SGV->getName(), &DstM);
702 new GlobalVariable(DstM, TypeMap.get(SGV->getValueType()),
703 /*isConstant*/ false, GlobalValue::ExternalLinkage,
704 /*init*/ nullptr, SGV->getName(),
705 /*insertbefore*/ nullptr,
706 SGV->getThreadLocalMode(), SGV->getAddressSpace());
710 NewGV->setLinkage(SGV->getLinkage());
711 else if (SGV->hasExternalWeakLinkage())
712 NewGV->setLinkage(GlobalValue::ExternalWeakLinkage);
714 if (auto *NewGO = dyn_cast<GlobalObject>(NewGV)) {
715 // Metadata for global variables and function declarations is copied eagerly.
716 if (isa<GlobalVariable>(SGV) || SGV->isDeclaration())
717 NewGO->copyMetadata(cast<GlobalObject>(SGV), 0);
720 // Remove these copied constants in case this stays a declaration, since
721 // they point to the source module. If the def is linked the values will
722 // be mapped in during linkFunctionBody.
723 if (auto *NewF = dyn_cast<Function>(NewGV)) {
724 NewF->setPersonalityFn(nullptr);
725 NewF->setPrefixData(nullptr);
726 NewF->setPrologueData(nullptr);
732 static StringRef getTypeNamePrefix(StringRef Name) {
733 size_t DotPos = Name.rfind('.');
734 return (DotPos == 0 || DotPos == StringRef::npos || Name.back() == '.' ||
735 !isdigit(static_cast<unsigned char>(Name[DotPos + 1])))
737 : Name.substr(0, DotPos);
740 /// Loop over all of the linked values to compute type mappings. For example,
741 /// if we link "extern Foo *x" and "Foo *x = NULL", then we have two struct
742 /// types 'Foo' but one got renamed when the module was loaded into the same
744 void IRLinker::computeTypeMapping() {
745 for (GlobalValue &SGV : SrcM->globals()) {
746 GlobalValue *DGV = getLinkedToGlobal(&SGV);
750 if (!DGV->hasAppendingLinkage() || !SGV.hasAppendingLinkage()) {
751 TypeMap.addTypeMapping(DGV->getType(), SGV.getType());
755 // Unify the element type of appending arrays.
756 ArrayType *DAT = cast<ArrayType>(DGV->getValueType());
757 ArrayType *SAT = cast<ArrayType>(SGV.getValueType());
758 TypeMap.addTypeMapping(DAT->getElementType(), SAT->getElementType());
761 for (GlobalValue &SGV : *SrcM)
762 if (GlobalValue *DGV = getLinkedToGlobal(&SGV)) {
763 if (DGV->getType() == SGV.getType()) {
764 // If the types of DGV and SGV are the same, it means that DGV is from
765 // the source module and got added to DstM from a shared metadata. We
766 // shouldn't map this type to itself in case the type's components get
767 // remapped to a new type from DstM (for instance, during the loop over
768 // SrcM->getIdentifiedStructTypes() below).
772 TypeMap.addTypeMapping(DGV->getType(), SGV.getType());
775 for (GlobalValue &SGV : SrcM->aliases())
776 if (GlobalValue *DGV = getLinkedToGlobal(&SGV))
777 TypeMap.addTypeMapping(DGV->getType(), SGV.getType());
779 // Incorporate types by name, scanning all the types in the source module.
780 // At this point, the destination module may have a type "%foo = { i32 }" for
781 // example. When the source module got loaded into the same LLVMContext, if
782 // it had the same type, it would have been renamed to "%foo.42 = { i32 }".
783 std::vector<StructType *> Types = SrcM->getIdentifiedStructTypes();
784 for (StructType *ST : Types) {
788 if (TypeMap.DstStructTypesSet.hasType(ST)) {
789 // This is actually a type from the destination module.
790 // getIdentifiedStructTypes() can have found it by walking debug info
791 // metadata nodes, some of which get linked by name when ODR Type Uniquing
792 // is enabled on the Context, from the source to the destination module.
796 auto STTypePrefix = getTypeNamePrefix(ST->getName());
797 if (STTypePrefix.size()== ST->getName().size())
800 // Check to see if the destination module has a struct with the prefix name.
801 StructType *DST = DstM.getTypeByName(STTypePrefix);
805 // Don't use it if this actually came from the source module. They're in
806 // the same LLVMContext after all. Also don't use it unless the type is
807 // actually used in the destination module. This can happen in situations
812 // %Z = type { %A } %B = type { %C.1 }
813 // %A = type { %B.1, [7 x i8] } %C.1 = type { i8* }
814 // %B.1 = type { %C } %A.2 = type { %B.3, [5 x i8] }
815 // %C = type { i8* } %B.3 = type { %C.1 }
817 // When we link Module B with Module A, the '%B' in Module B is
818 // used. However, that would then use '%C.1'. But when we process '%C.1',
819 // we prefer to take the '%C' version. So we are then left with both
820 // '%C.1' and '%C' being used for the same types. This leads to some
821 // variables using one type and some using the other.
822 if (TypeMap.DstStructTypesSet.hasType(DST))
823 TypeMap.addTypeMapping(DST, ST);
826 // Now that we have discovered all of the type equivalences, get a body for
827 // any 'opaque' types in the dest module that are now resolved.
828 TypeMap.linkDefinedTypeBodies();
831 static void getArrayElements(const Constant *C,
832 SmallVectorImpl<Constant *> &Dest) {
833 unsigned NumElements = cast<ArrayType>(C->getType())->getNumElements();
835 for (unsigned i = 0; i != NumElements; ++i)
836 Dest.push_back(C->getAggregateElement(i));
839 /// If there were any appending global variables, link them together now.
841 IRLinker::linkAppendingVarProto(GlobalVariable *DstGV,
842 const GlobalVariable *SrcGV) {
843 Type *EltTy = cast<ArrayType>(TypeMap.get(SrcGV->getValueType()))
846 // FIXME: This upgrade is done during linking to support the C API. Once the
847 // old form is deprecated, we should move this upgrade to
848 // llvm::UpgradeGlobalVariable() and simplify the logic here and in
849 // Mapper::mapAppendingVariable() in ValueMapper.cpp.
850 StringRef Name = SrcGV->getName();
851 bool IsNewStructor = false;
852 bool IsOldStructor = false;
853 if (Name == "llvm.global_ctors" || Name == "llvm.global_dtors") {
854 if (cast<StructType>(EltTy)->getNumElements() == 3)
855 IsNewStructor = true;
857 IsOldStructor = true;
860 PointerType *VoidPtrTy = Type::getInt8Ty(SrcGV->getContext())->getPointerTo();
862 auto &ST = *cast<StructType>(EltTy);
863 Type *Tys[3] = {ST.getElementType(0), ST.getElementType(1), VoidPtrTy};
864 EltTy = StructType::get(SrcGV->getContext(), Tys, false);
867 uint64_t DstNumElements = 0;
869 ArrayType *DstTy = cast<ArrayType>(DstGV->getValueType());
870 DstNumElements = DstTy->getNumElements();
872 if (!SrcGV->hasAppendingLinkage() || !DstGV->hasAppendingLinkage())
874 "Linking globals named '" + SrcGV->getName() +
875 "': can only link appending global with another appending "
878 // Check to see that they two arrays agree on type.
879 if (EltTy != DstTy->getElementType())
880 return stringErr("Appending variables with different element types!");
881 if (DstGV->isConstant() != SrcGV->isConstant())
882 return stringErr("Appending variables linked with different const'ness!");
884 if (DstGV->getAlignment() != SrcGV->getAlignment())
886 "Appending variables with different alignment need to be linked!");
888 if (DstGV->getVisibility() != SrcGV->getVisibility())
890 "Appending variables with different visibility need to be linked!");
892 if (DstGV->hasGlobalUnnamedAddr() != SrcGV->hasGlobalUnnamedAddr())
894 "Appending variables with different unnamed_addr need to be linked!");
896 if (DstGV->getSection() != SrcGV->getSection())
898 "Appending variables with different section name need to be linked!");
901 SmallVector<Constant *, 16> SrcElements;
902 getArrayElements(SrcGV->getInitializer(), SrcElements);
905 auto It = remove_if(SrcElements, [this](Constant *E) {
907 dyn_cast<GlobalValue>(E->getAggregateElement(2)->stripPointerCasts());
910 GlobalValue *DGV = getLinkedToGlobal(Key);
911 return !shouldLink(DGV, *Key);
913 SrcElements.erase(It, SrcElements.end());
915 uint64_t NewSize = DstNumElements + SrcElements.size();
916 ArrayType *NewType = ArrayType::get(EltTy, NewSize);
918 // Create the new global variable.
919 GlobalVariable *NG = new GlobalVariable(
920 DstM, NewType, SrcGV->isConstant(), SrcGV->getLinkage(),
921 /*init*/ nullptr, /*name*/ "", DstGV, SrcGV->getThreadLocalMode(),
922 SrcGV->getAddressSpace());
924 NG->copyAttributesFrom(SrcGV);
925 forceRenaming(NG, SrcGV->getName());
927 Constant *Ret = ConstantExpr::getBitCast(NG, TypeMap.get(SrcGV->getType()));
929 Mapper.scheduleMapAppendingVariable(*NG,
930 DstGV ? DstGV->getInitializer() : nullptr,
931 IsOldStructor, SrcElements);
933 // Replace any uses of the two global variables with uses of the new
936 RAUWWorklist.push_back(
937 std::make_pair(DstGV, ConstantExpr::getBitCast(NG, DstGV->getType())));
943 bool IRLinker::shouldLink(GlobalValue *DGV, GlobalValue &SGV) {
944 if (ValuesToLink.count(&SGV) || SGV.hasLocalLinkage())
947 if (DGV && !DGV->isDeclarationForLinker())
950 if (SGV.isDeclaration() || DoneLinkingBodies)
953 // Callback to the client to give a chance to lazily add the Global to the
954 // list of value to link.
955 bool LazilyAdded = false;
956 AddLazyFor(SGV, [this, &LazilyAdded](GlobalValue &GV) {
963 Expected<Constant *> IRLinker::linkGlobalValueProto(GlobalValue *SGV,
964 bool ForIndirectSymbol) {
965 GlobalValue *DGV = getLinkedToGlobal(SGV);
967 bool ShouldLink = shouldLink(DGV, *SGV);
969 // just missing from map
971 auto I = ValueMap.find(SGV);
972 if (I != ValueMap.end())
973 return cast<Constant>(I->second);
975 I = IndirectSymbolValueMap.find(SGV);
976 if (I != IndirectSymbolValueMap.end())
977 return cast<Constant>(I->second);
980 if (!ShouldLink && ForIndirectSymbol)
983 // Handle the ultra special appending linkage case first.
984 assert(!DGV || SGV->hasAppendingLinkage() == DGV->hasAppendingLinkage());
985 if (SGV->hasAppendingLinkage())
986 return linkAppendingVarProto(cast_or_null<GlobalVariable>(DGV),
987 cast<GlobalVariable>(SGV));
990 if (DGV && !ShouldLink) {
993 // If we are done linking global value bodies (i.e. we are performing
994 // metadata linking), don't link in the global value due to this
995 // reference, simply map it to null.
996 if (DoneLinkingBodies)
999 NewGV = copyGlobalValueProto(SGV, ShouldLink || ForIndirectSymbol);
1000 if (ShouldLink || !ForIndirectSymbol)
1001 forceRenaming(NewGV, SGV->getName());
1004 // Overloaded intrinsics have overloaded types names as part of their
1005 // names. If we renamed overloaded types we should rename the intrinsic
1007 if (Function *F = dyn_cast<Function>(NewGV))
1008 if (auto Remangled = Intrinsic::remangleIntrinsicFunction(F))
1009 NewGV = Remangled.getValue();
1011 if (ShouldLink || ForIndirectSymbol) {
1012 if (const Comdat *SC = SGV->getComdat()) {
1013 if (auto *GO = dyn_cast<GlobalObject>(NewGV)) {
1014 Comdat *DC = DstM.getOrInsertComdat(SC->getName());
1015 DC->setSelectionKind(SC->getSelectionKind());
1021 if (!ShouldLink && ForIndirectSymbol)
1022 NewGV->setLinkage(GlobalValue::InternalLinkage);
1024 Constant *C = NewGV;
1025 // Only create a bitcast if necessary. In particular, with
1026 // DebugTypeODRUniquing we may reach metadata in the destination module
1027 // containing a GV from the source module, in which case SGV will be
1028 // the same as DGV and NewGV, and TypeMap.get() will assert since it
1029 // assumes it is being invoked on a type in the source module.
1030 if (DGV && NewGV != SGV) {
1031 C = ConstantExpr::getPointerBitCastOrAddrSpaceCast(
1032 NewGV, TypeMap.get(SGV->getType()));
1035 if (DGV && NewGV != DGV) {
1036 // Schedule "replace all uses with" to happen after materializing is
1037 // done. It is not safe to do it now, since ValueMapper may be holding
1038 // pointers to constants that will get deleted if RAUW runs.
1039 RAUWWorklist.push_back(std::make_pair(
1041 ConstantExpr::getPointerBitCastOrAddrSpaceCast(NewGV, DGV->getType())));
1047 /// Update the initializers in the Dest module now that all globals that may be
1048 /// referenced are in Dest.
1049 void IRLinker::linkGlobalVariable(GlobalVariable &Dst, GlobalVariable &Src) {
1050 // Figure out what the initializer looks like in the dest module.
1051 Mapper.scheduleMapGlobalInitializer(Dst, *Src.getInitializer());
1054 /// Copy the source function over into the dest function and fix up references
1055 /// to values. At this point we know that Dest is an external function, and
1056 /// that Src is not.
1057 Error IRLinker::linkFunctionBody(Function &Dst, Function &Src) {
1058 assert(Dst.isDeclaration() && !Src.isDeclaration());
1060 // Materialize if needed.
1061 if (Error Err = Src.materialize())
1064 // Link in the operands without remapping.
1065 if (Src.hasPrefixData())
1066 Dst.setPrefixData(Src.getPrefixData());
1067 if (Src.hasPrologueData())
1068 Dst.setPrologueData(Src.getPrologueData());
1069 if (Src.hasPersonalityFn())
1070 Dst.setPersonalityFn(Src.getPersonalityFn());
1072 // Copy over the metadata attachments without remapping.
1073 Dst.copyMetadata(&Src, 0);
1075 // Steal arguments and splice the body of Src into Dst.
1076 Dst.stealArgumentListFrom(Src);
1077 Dst.getBasicBlockList().splice(Dst.end(), Src.getBasicBlockList());
1079 // Everything has been moved over. Remap it.
1080 Mapper.scheduleRemapFunction(Dst);
1081 return Error::success();
1084 void IRLinker::linkIndirectSymbolBody(GlobalIndirectSymbol &Dst,
1085 GlobalIndirectSymbol &Src) {
1086 Mapper.scheduleMapGlobalIndirectSymbol(Dst, *Src.getIndirectSymbol(),
1087 IndirectSymbolMCID);
1090 Error IRLinker::linkGlobalValueBody(GlobalValue &Dst, GlobalValue &Src) {
1091 if (auto *F = dyn_cast<Function>(&Src))
1092 return linkFunctionBody(cast<Function>(Dst), *F);
1093 if (auto *GVar = dyn_cast<GlobalVariable>(&Src)) {
1094 linkGlobalVariable(cast<GlobalVariable>(Dst), *GVar);
1095 return Error::success();
1097 linkIndirectSymbolBody(cast<GlobalIndirectSymbol>(Dst), cast<GlobalIndirectSymbol>(Src));
1098 return Error::success();
1101 void IRLinker::flushRAUWWorklist() {
1102 for (const auto &Elem : RAUWWorklist) {
1105 std::tie(Old, New) = Elem;
1107 Old->replaceAllUsesWith(New);
1108 Old->eraseFromParent();
1110 RAUWWorklist.clear();
1113 void IRLinker::prepareCompileUnitsForImport() {
1114 NamedMDNode *SrcCompileUnits = SrcM->getNamedMetadata("llvm.dbg.cu");
1115 if (!SrcCompileUnits)
1117 // When importing for ThinLTO, prevent importing of types listed on
1118 // the DICompileUnit that we don't need a copy of in the importing
1119 // module. They will be emitted by the originating module.
1120 for (unsigned I = 0, E = SrcCompileUnits->getNumOperands(); I != E; ++I) {
1121 auto *CU = cast<DICompileUnit>(SrcCompileUnits->getOperand(I));
1122 assert(CU && "Expected valid compile unit");
1123 // Enums, macros, and retained types don't need to be listed on the
1124 // imported DICompileUnit. This means they will only be imported
1125 // if reached from the mapped IR. Do this by setting their value map
1126 // entries to nullptr, which will automatically prevent their importing
1127 // when reached from the DICompileUnit during metadata mapping.
1128 ValueMap.MD()[CU->getRawEnumTypes()].reset(nullptr);
1129 ValueMap.MD()[CU->getRawMacros()].reset(nullptr);
1130 ValueMap.MD()[CU->getRawRetainedTypes()].reset(nullptr);
1131 // The original definition (or at least its debug info - if the variable is
1132 // internalized an optimized away) will remain in the source module, so
1133 // there's no need to import them.
1134 // If LLVM ever does more advanced optimizations on global variables
1135 // (removing/localizing write operations, for instance) that can track
1136 // through debug info, this decision may need to be revisited - but do so
1137 // with care when it comes to debug info size. Emitting small CUs containing
1138 // only a few imported entities into every destination module may be very
1139 // size inefficient.
1140 ValueMap.MD()[CU->getRawGlobalVariables()].reset(nullptr);
1142 // Imported entities only need to be mapped in if they have local
1143 // scope, as those might correspond to an imported entity inside a
1144 // function being imported (any locally scoped imported entities that
1145 // don't end up referenced by an imported function will not be emitted
1146 // into the object). Imported entities not in a local scope
1147 // (e.g. on the namespace) only need to be emitted by the originating
1148 // module. Create a list of the locally scoped imported entities, and
1149 // replace the source CUs imported entity list with the new list, so
1150 // only those are mapped in.
1151 // FIXME: Locally-scoped imported entities could be moved to the
1152 // functions they are local to instead of listing them on the CU, and
1153 // we would naturally only link in those needed by function importing.
1154 SmallVector<TrackingMDNodeRef, 4> AllImportedModules;
1155 bool ReplaceImportedEntities = false;
1156 for (auto *IE : CU->getImportedEntities()) {
1157 DIScope *Scope = IE->getScope();
1158 assert(Scope && "Invalid Scope encoding!");
1159 if (isa<DILocalScope>(Scope))
1160 AllImportedModules.emplace_back(IE);
1162 ReplaceImportedEntities = true;
1164 if (ReplaceImportedEntities) {
1165 if (!AllImportedModules.empty())
1166 CU->replaceImportedEntities(MDTuple::get(
1168 SmallVector<Metadata *, 16>(AllImportedModules.begin(),
1169 AllImportedModules.end())));
1171 // If there were no local scope imported entities, we can map
1172 // the whole list to nullptr.
1173 ValueMap.MD()[CU->getRawImportedEntities()].reset(nullptr);
1178 /// Insert all of the named MDNodes in Src into the Dest module.
1179 void IRLinker::linkNamedMDNodes() {
1180 const NamedMDNode *SrcModFlags = SrcM->getModuleFlagsMetadata();
1181 for (const NamedMDNode &NMD : SrcM->named_metadata()) {
1182 // Don't link module flags here. Do them separately.
1183 if (&NMD == SrcModFlags)
1185 NamedMDNode *DestNMD = DstM.getOrInsertNamedMetadata(NMD.getName());
1186 // Add Src elements into Dest node.
1187 for (const MDNode *Op : NMD.operands())
1188 DestNMD->addOperand(Mapper.mapMDNode(*Op));
1192 /// Merge the linker flags in Src into the Dest module.
1193 Error IRLinker::linkModuleFlagsMetadata() {
1194 // If the source module has no module flags, we are done.
1195 const NamedMDNode *SrcModFlags = SrcM->getModuleFlagsMetadata();
1197 return Error::success();
1199 // If the destination module doesn't have module flags yet, then just copy
1200 // over the source module's flags.
1201 NamedMDNode *DstModFlags = DstM.getOrInsertModuleFlagsMetadata();
1202 if (DstModFlags->getNumOperands() == 0) {
1203 for (unsigned I = 0, E = SrcModFlags->getNumOperands(); I != E; ++I)
1204 DstModFlags->addOperand(SrcModFlags->getOperand(I));
1206 return Error::success();
1209 // First build a map of the existing module flags and requirements.
1210 DenseMap<MDString *, std::pair<MDNode *, unsigned>> Flags;
1211 SmallSetVector<MDNode *, 16> Requirements;
1212 for (unsigned I = 0, E = DstModFlags->getNumOperands(); I != E; ++I) {
1213 MDNode *Op = DstModFlags->getOperand(I);
1214 ConstantInt *Behavior = mdconst::extract<ConstantInt>(Op->getOperand(0));
1215 MDString *ID = cast<MDString>(Op->getOperand(1));
1217 if (Behavior->getZExtValue() == Module::Require) {
1218 Requirements.insert(cast<MDNode>(Op->getOperand(2)));
1220 Flags[ID] = std::make_pair(Op, I);
1224 // Merge in the flags from the source module, and also collect its set of
1226 for (unsigned I = 0, E = SrcModFlags->getNumOperands(); I != E; ++I) {
1227 MDNode *SrcOp = SrcModFlags->getOperand(I);
1228 ConstantInt *SrcBehavior =
1229 mdconst::extract<ConstantInt>(SrcOp->getOperand(0));
1230 MDString *ID = cast<MDString>(SrcOp->getOperand(1));
1233 std::tie(DstOp, DstIndex) = Flags.lookup(ID);
1234 unsigned SrcBehaviorValue = SrcBehavior->getZExtValue();
1236 // If this is a requirement, add it and continue.
1237 if (SrcBehaviorValue == Module::Require) {
1238 // If the destination module does not already have this requirement, add
1240 if (Requirements.insert(cast<MDNode>(SrcOp->getOperand(2)))) {
1241 DstModFlags->addOperand(SrcOp);
1246 // If there is no existing flag with this ID, just add it.
1248 Flags[ID] = std::make_pair(SrcOp, DstModFlags->getNumOperands());
1249 DstModFlags->addOperand(SrcOp);
1253 // Otherwise, perform a merge.
1254 ConstantInt *DstBehavior =
1255 mdconst::extract<ConstantInt>(DstOp->getOperand(0));
1256 unsigned DstBehaviorValue = DstBehavior->getZExtValue();
1258 auto overrideDstValue = [&]() {
1259 DstModFlags->setOperand(DstIndex, SrcOp);
1260 Flags[ID].first = SrcOp;
1263 // If either flag has override behavior, handle it first.
1264 if (DstBehaviorValue == Module::Override) {
1265 // Diagnose inconsistent flags which both have override behavior.
1266 if (SrcBehaviorValue == Module::Override &&
1267 SrcOp->getOperand(2) != DstOp->getOperand(2))
1268 return stringErr("linking module flags '" + ID->getString() +
1269 "': IDs have conflicting override values in '" +
1270 SrcM->getModuleIdentifier() + "' and '" +
1271 DstM.getModuleIdentifier() + "'");
1273 } else if (SrcBehaviorValue == Module::Override) {
1274 // Update the destination flag to that of the source.
1279 // Diagnose inconsistent merge behavior types.
1280 if (SrcBehaviorValue != DstBehaviorValue) {
1281 bool MaxAndWarn = (SrcBehaviorValue == Module::Max &&
1282 DstBehaviorValue == Module::Warning) ||
1283 (DstBehaviorValue == Module::Max &&
1284 SrcBehaviorValue == Module::Warning);
1286 return stringErr("linking module flags '" + ID->getString() +
1287 "': IDs have conflicting behaviors in '" +
1288 SrcM->getModuleIdentifier() + "' and '" +
1289 DstM.getModuleIdentifier() + "'");
1292 auto replaceDstValue = [&](MDNode *New) {
1293 Metadata *FlagOps[] = {DstOp->getOperand(0), ID, New};
1294 MDNode *Flag = MDNode::get(DstM.getContext(), FlagOps);
1295 DstModFlags->setOperand(DstIndex, Flag);
1296 Flags[ID].first = Flag;
1299 // Emit a warning if the values differ and either source or destination
1300 // request Warning behavior.
1301 if ((DstBehaviorValue == Module::Warning ||
1302 SrcBehaviorValue == Module::Warning) &&
1303 SrcOp->getOperand(2) != DstOp->getOperand(2)) {
1305 raw_string_ostream(Str)
1306 << "linking module flags '" << ID->getString()
1307 << "': IDs have conflicting values ('" << *SrcOp->getOperand(2)
1308 << "' from " << SrcM->getModuleIdentifier() << " with '"
1309 << *DstOp->getOperand(2) << "' from " << DstM.getModuleIdentifier()
1314 // Choose the maximum if either source or destination request Max behavior.
1315 if (DstBehaviorValue == Module::Max || SrcBehaviorValue == Module::Max) {
1316 ConstantInt *DstValue =
1317 mdconst::extract<ConstantInt>(DstOp->getOperand(2));
1318 ConstantInt *SrcValue =
1319 mdconst::extract<ConstantInt>(SrcOp->getOperand(2));
1321 // The resulting flag should have a Max behavior, and contain the maximum
1322 // value from between the source and destination values.
1323 Metadata *FlagOps[] = {
1324 (DstBehaviorValue != Module::Max ? SrcOp : DstOp)->getOperand(0), ID,
1325 (SrcValue->getZExtValue() > DstValue->getZExtValue() ? SrcOp : DstOp)
1327 MDNode *Flag = MDNode::get(DstM.getContext(), FlagOps);
1328 DstModFlags->setOperand(DstIndex, Flag);
1329 Flags[ID].first = Flag;
1333 // Perform the merge for standard behavior types.
1334 switch (SrcBehaviorValue) {
1335 case Module::Require:
1336 case Module::Override:
1337 llvm_unreachable("not possible");
1338 case Module::Error: {
1339 // Emit an error if the values differ.
1340 if (SrcOp->getOperand(2) != DstOp->getOperand(2))
1341 return stringErr("linking module flags '" + ID->getString() +
1342 "': IDs have conflicting values in '" +
1343 SrcM->getModuleIdentifier() + "' and '" +
1344 DstM.getModuleIdentifier() + "'");
1347 case Module::Warning: {
1353 case Module::Append: {
1354 MDNode *DstValue = cast<MDNode>(DstOp->getOperand(2));
1355 MDNode *SrcValue = cast<MDNode>(SrcOp->getOperand(2));
1356 SmallVector<Metadata *, 8> MDs;
1357 MDs.reserve(DstValue->getNumOperands() + SrcValue->getNumOperands());
1358 MDs.append(DstValue->op_begin(), DstValue->op_end());
1359 MDs.append(SrcValue->op_begin(), SrcValue->op_end());
1361 replaceDstValue(MDNode::get(DstM.getContext(), MDs));
1364 case Module::AppendUnique: {
1365 SmallSetVector<Metadata *, 16> Elts;
1366 MDNode *DstValue = cast<MDNode>(DstOp->getOperand(2));
1367 MDNode *SrcValue = cast<MDNode>(SrcOp->getOperand(2));
1368 Elts.insert(DstValue->op_begin(), DstValue->op_end());
1369 Elts.insert(SrcValue->op_begin(), SrcValue->op_end());
1371 replaceDstValue(MDNode::get(DstM.getContext(),
1372 makeArrayRef(Elts.begin(), Elts.end())));
1379 // Check all of the requirements.
1380 for (unsigned I = 0, E = Requirements.size(); I != E; ++I) {
1381 MDNode *Requirement = Requirements[I];
1382 MDString *Flag = cast<MDString>(Requirement->getOperand(0));
1383 Metadata *ReqValue = Requirement->getOperand(1);
1385 MDNode *Op = Flags[Flag].first;
1386 if (!Op || Op->getOperand(2) != ReqValue)
1387 return stringErr("linking module flags '" + Flag->getString() +
1388 "': does not have the required value");
1390 return Error::success();
1393 /// Return InlineAsm adjusted with target-specific directives if required.
1394 /// For ARM and Thumb, we have to add directives to select the appropriate ISA
1395 /// to support mixing module-level inline assembly from ARM and Thumb modules.
1396 static std::string adjustInlineAsm(const std::string &InlineAsm,
1397 const Triple &Triple) {
1398 if (Triple.getArch() == Triple::thumb || Triple.getArch() == Triple::thumbeb)
1399 return ".text\n.balign 2\n.thumb\n" + InlineAsm;
1400 if (Triple.getArch() == Triple::arm || Triple.getArch() == Triple::armeb)
1401 return ".text\n.balign 4\n.arm\n" + InlineAsm;
1405 Error IRLinker::run() {
1406 // Ensure metadata materialized before value mapping.
1407 if (SrcM->getMaterializer())
1408 if (Error Err = SrcM->getMaterializer()->materializeMetadata())
1411 // Inherit the target data from the source module if the destination module
1412 // doesn't have one already.
1413 if (DstM.getDataLayout().isDefault())
1414 DstM.setDataLayout(SrcM->getDataLayout());
1416 if (SrcM->getDataLayout() != DstM.getDataLayout()) {
1417 emitWarning("Linking two modules of different data layouts: '" +
1418 SrcM->getModuleIdentifier() + "' is '" +
1419 SrcM->getDataLayoutStr() + "' whereas '" +
1420 DstM.getModuleIdentifier() + "' is '" +
1421 DstM.getDataLayoutStr() + "'\n");
1424 // Copy the target triple from the source to dest if the dest's is empty.
1425 if (DstM.getTargetTriple().empty() && !SrcM->getTargetTriple().empty())
1426 DstM.setTargetTriple(SrcM->getTargetTriple());
1428 Triple SrcTriple(SrcM->getTargetTriple()), DstTriple(DstM.getTargetTriple());
1430 if (!SrcM->getTargetTriple().empty()&&
1431 !SrcTriple.isCompatibleWith(DstTriple))
1432 emitWarning("Linking two modules of different target triples: " +
1433 SrcM->getModuleIdentifier() + "' is '" +
1434 SrcM->getTargetTriple() + "' whereas '" +
1435 DstM.getModuleIdentifier() + "' is '" + DstM.getTargetTriple() +
1438 DstM.setTargetTriple(SrcTriple.merge(DstTriple));
1440 // Append the module inline asm string.
1441 if (!IsPerformingImport && !SrcM->getModuleInlineAsm().empty()) {
1442 std::string SrcModuleInlineAsm = adjustInlineAsm(SrcM->getModuleInlineAsm(),
1444 if (DstM.getModuleInlineAsm().empty())
1445 DstM.setModuleInlineAsm(SrcModuleInlineAsm);
1447 DstM.setModuleInlineAsm(DstM.getModuleInlineAsm() + "\n" +
1448 SrcModuleInlineAsm);
1451 // Loop over all of the linked values to compute type mappings.
1452 computeTypeMapping();
1454 std::reverse(Worklist.begin(), Worklist.end());
1455 while (!Worklist.empty()) {
1456 GlobalValue *GV = Worklist.back();
1457 Worklist.pop_back();
1460 if (ValueMap.find(GV) != ValueMap.end() ||
1461 IndirectSymbolValueMap.find(GV) != IndirectSymbolValueMap.end())
1464 assert(!GV->isDeclaration());
1465 Mapper.mapValue(*GV);
1467 return std::move(*FoundError);
1468 flushRAUWWorklist();
1471 // Note that we are done linking global value bodies. This prevents
1472 // metadata linking from creating new references.
1473 DoneLinkingBodies = true;
1474 Mapper.addFlags(RF_NullMapMissingGlobalValues);
1476 // Remap all of the named MDNodes in Src into the DstM module. We do this
1477 // after linking GlobalValues so that MDNodes that reference GlobalValues
1478 // are properly remapped.
1481 // Merge the module flags into the DstM module.
1482 return linkModuleFlagsMetadata();
1485 IRMover::StructTypeKeyInfo::KeyTy::KeyTy(ArrayRef<Type *> E, bool P)
1486 : ETypes(E), IsPacked(P) {}
1488 IRMover::StructTypeKeyInfo::KeyTy::KeyTy(const StructType *ST)
1489 : ETypes(ST->elements()), IsPacked(ST->isPacked()) {}
1491 bool IRMover::StructTypeKeyInfo::KeyTy::operator==(const KeyTy &That) const {
1492 return IsPacked == That.IsPacked && ETypes == That.ETypes;
1495 bool IRMover::StructTypeKeyInfo::KeyTy::operator!=(const KeyTy &That) const {
1496 return !this->operator==(That);
1499 StructType *IRMover::StructTypeKeyInfo::getEmptyKey() {
1500 return DenseMapInfo<StructType *>::getEmptyKey();
1503 StructType *IRMover::StructTypeKeyInfo::getTombstoneKey() {
1504 return DenseMapInfo<StructType *>::getTombstoneKey();
1507 unsigned IRMover::StructTypeKeyInfo::getHashValue(const KeyTy &Key) {
1508 return hash_combine(hash_combine_range(Key.ETypes.begin(), Key.ETypes.end()),
1512 unsigned IRMover::StructTypeKeyInfo::getHashValue(const StructType *ST) {
1513 return getHashValue(KeyTy(ST));
1516 bool IRMover::StructTypeKeyInfo::isEqual(const KeyTy &LHS,
1517 const StructType *RHS) {
1518 if (RHS == getEmptyKey() || RHS == getTombstoneKey())
1520 return LHS == KeyTy(RHS);
1523 bool IRMover::StructTypeKeyInfo::isEqual(const StructType *LHS,
1524 const StructType *RHS) {
1525 if (RHS == getEmptyKey() || RHS == getTombstoneKey())
1527 return KeyTy(LHS) == KeyTy(RHS);
1530 void IRMover::IdentifiedStructTypeSet::addNonOpaque(StructType *Ty) {
1531 assert(!Ty->isOpaque());
1532 NonOpaqueStructTypes.insert(Ty);
1535 void IRMover::IdentifiedStructTypeSet::switchToNonOpaque(StructType *Ty) {
1536 assert(!Ty->isOpaque());
1537 NonOpaqueStructTypes.insert(Ty);
1538 bool Removed = OpaqueStructTypes.erase(Ty);
1543 void IRMover::IdentifiedStructTypeSet::addOpaque(StructType *Ty) {
1544 assert(Ty->isOpaque());
1545 OpaqueStructTypes.insert(Ty);
1549 IRMover::IdentifiedStructTypeSet::findNonOpaque(ArrayRef<Type *> ETypes,
1551 IRMover::StructTypeKeyInfo::KeyTy Key(ETypes, IsPacked);
1552 auto I = NonOpaqueStructTypes.find_as(Key);
1553 return I == NonOpaqueStructTypes.end() ? nullptr : *I;
1556 bool IRMover::IdentifiedStructTypeSet::hasType(StructType *Ty) {
1558 return OpaqueStructTypes.count(Ty);
1559 auto I = NonOpaqueStructTypes.find(Ty);
1560 return I == NonOpaqueStructTypes.end() ? false : *I == Ty;
1563 IRMover::IRMover(Module &M) : Composite(M) {
1564 TypeFinder StructTypes;
1565 StructTypes.run(M, /* OnlyNamed */ false);
1566 for (StructType *Ty : StructTypes) {
1568 IdentifiedStructTypes.addOpaque(Ty);
1570 IdentifiedStructTypes.addNonOpaque(Ty);
1572 // Self-map metadatas in the destination module. This is needed when
1573 // DebugTypeODRUniquing is enabled on the LLVMContext, since metadata in the
1574 // destination module may be reached from the source module.
1575 for (auto *MD : StructTypes.getVisitedMetadata()) {
1576 SharedMDs[MD].reset(const_cast<MDNode *>(MD));
1580 Error IRMover::move(
1581 std::unique_ptr<Module> Src, ArrayRef<GlobalValue *> ValuesToLink,
1582 std::function<void(GlobalValue &, ValueAdder Add)> AddLazyFor,
1583 bool IsPerformingImport) {
1584 IRLinker TheIRLinker(Composite, SharedMDs, IdentifiedStructTypes,
1585 std::move(Src), ValuesToLink, std::move(AddLazyFor),
1586 IsPerformingImport);
1587 Error E = TheIRLinker.run();
1588 Composite.dropTriviallyDeadConstantArrays();