X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FLinker%2FLinkModules.cpp;h=edee55a1f9f65fc50ea54142bce1f7d010da37d2;hb=36d161829490a6e8655db29b13bb247ea4717800;hp=de62c3b94d05809a0075bf4b7e4900d8de1d988b;hpb=9423af6b706c3a40c0c51d6ef757e752dd6454e2;p=oota-llvm.git diff --git a/lib/Linker/LinkModules.cpp b/lib/Linker/LinkModules.cpp index de62c3b94d0..edee55a1f9f 100644 --- a/lib/Linker/LinkModules.cpp +++ b/lib/Linker/LinkModules.cpp @@ -18,7 +18,9 @@ #include "llvm/ADT/SetVector.h" #include "llvm/ADT/SmallString.h" #include "llvm/ADT/Statistic.h" +#include "llvm/ADT/Triple.h" #include "llvm/IR/Constants.h" +#include "llvm/IR/DebugInfo.h" #include "llvm/IR/DiagnosticInfo.h" #include "llvm/IR/DiagnosticPrinter.h" #include "llvm/IR/LLVMContext.h" @@ -224,6 +226,7 @@ void TypeMapTy::linkDefinedTypeBodies() { Elements[I] = get(SrcSTy->getElementType(I)); DstSTy->setBody(Elements, SrcSTy->isPacked()); + DstStructTypesSet.switchToNonOpaque(DstSTy); } SrcDefinitionsToResolve.clear(); DstResolvedOpaqueTypes.clear(); @@ -362,18 +365,14 @@ class ModuleLinker; /// Creates prototypes for functions that are lazily linked on the fly. This /// speeds up linking for modules with many/ lazily linked functions of which /// few get used. -class ValueMaterializerTy : public ValueMaterializer { - TypeMapTy &TypeMap; - Module *DstM; - std::vector &LazilyLinkFunctions; +class ValueMaterializerTy final : public ValueMaterializer { + ModuleLinker *ModLinker; public: - ValueMaterializerTy(TypeMapTy &TypeMap, Module *DstM, - std::vector &LazilyLinkFunctions) - : ValueMaterializer(), TypeMap(TypeMap), DstM(DstM), - LazilyLinkFunctions(LazilyLinkFunctions) {} + ValueMaterializerTy(ModuleLinker *ModLinker) : ModLinker(ModLinker) {} - Value *materializeValueFor(Value *V) override; + Value *materializeDeclFor(Value *V) override; + void materializeInitFor(GlobalValue *New, GlobalValue *Old) override; }; class LinkDiagnosticInfo : public DiagnosticInfo { @@ -411,29 +410,82 @@ class ModuleLinker { std::vector AppendingVars; // Set of items not to link in from source. - SmallPtrSet DoNotLinkFromSource; + SmallPtrSet DoNotLinkFromSource; - // Vector of functions to lazily link in. - std::vector LazilyLinkFunctions; + DiagnosticHandlerFunction DiagnosticHandler; - Linker::DiagnosticHandlerFunction DiagnosticHandler; + /// For symbol clashes, prefer those from Src. + unsigned Flags; + + /// Function index passed into ModuleLinker for using in function + /// importing/exporting handling. + const FunctionInfoIndex *ImportIndex; + + /// Function to import from source module, all other functions are + /// imported as declarations instead of definitions. + Function *ImportFunction; + + /// Set to true if the given FunctionInfoIndex contains any functions + /// from this source module, in which case we must conservatively assume + /// that any of its functions may be imported into another module + /// as part of a different backend compilation process. + bool HasExportedFunctions; + + /// Set to true when all global value body linking is complete (including + /// lazy linking). Used to prevent metadata linking from creating new + /// references. + bool DoneLinkingBodies; + + bool HasError = false; public: ModuleLinker(Module *dstM, Linker::IdentifiedStructTypeSet &Set, Module *srcM, - Linker::DiagnosticHandlerFunction DiagnosticHandler) - : DstM(dstM), SrcM(srcM), TypeMap(Set), - ValMaterializer(TypeMap, DstM, LazilyLinkFunctions), - DiagnosticHandler(DiagnosticHandler) {} + DiagnosticHandlerFunction DiagnosticHandler, unsigned Flags, + const FunctionInfoIndex *Index = nullptr, + Function *FuncToImport = nullptr) + : DstM(dstM), SrcM(srcM), TypeMap(Set), ValMaterializer(this), + DiagnosticHandler(DiagnosticHandler), Flags(Flags), ImportIndex(Index), + ImportFunction(FuncToImport), HasExportedFunctions(false), + DoneLinkingBodies(false) { + assert((ImportIndex || !ImportFunction) && + "Expect a FunctionInfoIndex when importing"); + // If we have a FunctionInfoIndex but no function to import, + // then this is the primary module being compiled in a ThinLTO + // backend compilation, and we need to see if it has functions that + // may be exported to another backend compilation. + if (ImportIndex && !ImportFunction) + HasExportedFunctions = ImportIndex->hasExportedFunctions(SrcM); + } bool run(); + Value *materializeDeclFor(Value *V); + void materializeInitFor(GlobalValue *New, GlobalValue *Old); private: + bool shouldOverrideFromSrc() { return Flags & Linker::OverrideFromSrc; } + bool shouldLinkOnlyNeeded() { return Flags & Linker::LinkOnlyNeeded; } + bool shouldInternalizeLinkedSymbols() { + return Flags & Linker::InternalizeLinkedSymbols; + } + + /// Handles cloning of a global values from the source module into + /// the destination module, including setting the attributes and visibility. + GlobalValue *copyGlobalValueProto(TypeMapTy &TypeMap, const GlobalValue *SGV, + const GlobalValue *DGV = nullptr); + + /// Check if we should promote the given local value to global scope. + bool doPromoteLocalToGlobal(const GlobalValue *SGV); + + /// Check if all global value body linking is complete. + bool doneLinkingBodies() { return DoneLinkingBodies; } + bool shouldLinkFromSource(bool &LinkFromSrc, const GlobalValue &Dest, const GlobalValue &Src); /// Helper method for setting a message and returning an error code. bool emitError(const Twine &Message) { DiagnosticHandler(LinkDiagnosticInfo(DS_Error, Message)); + HasError = true; return true; } @@ -452,17 +504,19 @@ private: ComdatsChosen; bool getComdatResult(const Comdat *SrcC, Comdat::SelectionKind &SK, bool &LinkFromSrc); + // Keep track of the global value members of each comdat in source. + DenseMap> ComdatMembers; /// Given a global in the source module, return the global in the /// destination module that is being linked to, if any. GlobalValue *getLinkedToGlobal(const GlobalValue *SrcGV) { // If the source has no name it can't link. If it has local linkage, // there is no name match-up going on. - if (!SrcGV->hasName() || SrcGV->hasLocalLinkage()) + if (!SrcGV->hasName() || GlobalValue::isLocalLinkage(getLinkage(SrcGV))) return nullptr; // Otherwise see if we have a match in the destination module's symtab. - GlobalValue *DGV = DstM->getNamedValue(SrcGV->getName()); + GlobalValue *DGV = DstM->getNamedValue(getName(SrcGV)); if (!DGV) return nullptr; @@ -480,20 +534,56 @@ private: void upgradeMismatchedGlobalArray(StringRef Name); void upgradeMismatchedGlobals(); + bool linkIfNeeded(GlobalValue &GV); bool linkAppendingVarProto(GlobalVariable *DstGV, const GlobalVariable *SrcGV); bool linkGlobalValueProto(GlobalValue *GV); - GlobalValue *linkGlobalVariableProto(const GlobalVariable *SGVar); - GlobalValue *linkFunctionProto(const Function *SF, GlobalValue *DGV); - GlobalValue *linkGlobalAliasProto(const GlobalAlias *SGA); - bool linkModuleFlagsMetadata(); - void linkAppendingVarInit(const AppendingVarInfo &AVI); - void linkGlobalInits(); - void linkFunctionBody(Function *Dst, Function *Src); - void linkAliasBodies(); + void linkAppendingVarInit(AppendingVarInfo &AVI); + + void linkGlobalInit(GlobalVariable &Dst, GlobalVariable &Src); + bool linkFunctionBody(Function &Dst, Function &Src); + void linkAliasBody(GlobalAlias &Dst, GlobalAlias &Src); + bool linkGlobalValueBody(GlobalValue &Src); + + /// Functions that take care of cloning a specific global value type + /// into the destination module. + GlobalVariable *copyGlobalVariableProto(TypeMapTy &TypeMap, + const GlobalVariable *SGVar); + Function *copyFunctionProto(TypeMapTy &TypeMap, const Function *SF); + GlobalValue *copyGlobalAliasProto(TypeMapTy &TypeMap, const GlobalAlias *SGA); + + /// Helper methods to check if we are importing from or potentially + /// exporting from the current source module. + bool isPerformingImport() { return ImportFunction != nullptr; } + bool isModuleExporting() { return HasExportedFunctions; } + + /// If we are importing from the source module, checks if we should + /// import SGV as a definition, otherwise import as a declaration. + bool doImportAsDefinition(const GlobalValue *SGV); + + /// Get the name for SGV that should be used in the linked destination + /// module. Specifically, this handles the case where we need to rename + /// a local that is being promoted to global scope. + std::string getName(const GlobalValue *SGV); + + /// Get the new linkage for SGV that should be used in the linked destination + /// module. Specifically, for ThinLTO importing or exporting it may need + /// to be adjusted. + GlobalValue::LinkageTypes getLinkage(const GlobalValue *SGV); + + /// Copies the necessary global value attributes and name from the source + /// to the newly cloned global value. + void copyGVAttributes(GlobalValue *NewGV, const GlobalValue *SrcGV); + + /// Updates the visibility for the new global cloned from the source + /// and, if applicable, linked with an existing destination global. + /// Handles visibility change required for promoted locals. + void setVisibility(GlobalValue *NewGV, const GlobalValue *SGV, + const GlobalValue *DGV = nullptr); + void linkNamedMDNodes(); }; } @@ -504,6 +594,9 @@ private: static void forceRenaming(GlobalValue *GV, StringRef Name) { // If the global doesn't force its name or if it already has the right name, // there is nothing for us to do. + // Note that any required local to global promotion should already be done, + // so promoted locals will not skip this handling as their linkage is no + // longer local. if (GV->hasLocalLinkage() || GV->getName() == Name) return; @@ -521,40 +614,336 @@ static void forceRenaming(GlobalValue *GV, StringRef Name) { /// copy additional attributes (those not needed to construct a GlobalValue) /// from the SrcGV to the DestGV. -static void copyGVAttributes(GlobalValue *DestGV, const GlobalValue *SrcGV) { - DestGV->copyAttributesFrom(SrcGV); - forceRenaming(DestGV, SrcGV->getName()); +void ModuleLinker::copyGVAttributes(GlobalValue *NewGV, + const GlobalValue *SrcGV) { + auto *GA = dyn_cast(SrcGV); + // Check for the special case of converting an alias (definition) to a + // non-alias (declaration). This can happen when we are importing and + // encounter a weak_any alias (weak_any defs may not be imported, see + // comments in ModuleLinker::getLinkage) or an alias whose base object is + // being imported as a declaration. In that case copy the attributes from the + // base object. + if (GA && !dyn_cast(NewGV)) { + assert(isPerformingImport() && !doImportAsDefinition(GA)); + NewGV->copyAttributesFrom(GA->getBaseObject()); + } else + NewGV->copyAttributesFrom(SrcGV); + forceRenaming(NewGV, getName(SrcGV)); } -static bool isLessConstraining(GlobalValue::VisibilityTypes a, - GlobalValue::VisibilityTypes b) { - if (a == GlobalValue::HiddenVisibility) +bool ModuleLinker::doImportAsDefinition(const GlobalValue *SGV) { + if (!isPerformingImport()) return false; - if (b == GlobalValue::HiddenVisibility) + auto *GA = dyn_cast(SGV); + if (GA) { + if (GA->hasWeakAnyLinkage()) + return false; + const GlobalObject *GO = GA->getBaseObject(); + if (!GO->hasLinkOnceODRLinkage()) + return false; + return doImportAsDefinition(GO); + } + // Always import GlobalVariable definitions, except for the special + // case of WeakAny which are imported as ExternalWeak declarations + // (see comments in ModuleLinker::getLinkage). The linkage changes + // described in ModuleLinker::getLinkage ensure the correct behavior (e.g. + // global variables with external linkage are transformed to + // available_externally definitions, which are ultimately turned into + // declarations after the EliminateAvailableExternally pass). + if (isa(SGV) && !SGV->isDeclaration() && + !SGV->hasWeakAnyLinkage()) return true; - if (a == GlobalValue::ProtectedVisibility) - return false; - if (b == GlobalValue::ProtectedVisibility) + // Only import the function requested for importing. + auto *SF = dyn_cast(SGV); + if (SF && SF == ImportFunction) return true; + // Otherwise no. return false; } -Value *ValueMaterializerTy::materializeValueFor(Value *V) { - Function *SF = dyn_cast(V); - if (!SF) +bool ModuleLinker::doPromoteLocalToGlobal(const GlobalValue *SGV) { + assert(SGV->hasLocalLinkage()); + // Both the imported references and the original local variable must + // be promoted. + if (!isPerformingImport() && !isModuleExporting()) + return false; + + // Local const variables never need to be promoted unless they are address + // taken. The imported uses can simply use the clone created in this module. + // For now we are conservative in determining which variables are not + // address taken by checking the unnamed addr flag. To be more aggressive, + // the address taken information must be checked earlier during parsing + // of the module and recorded in the function index for use when importing + // from that module. + auto *GVar = dyn_cast(SGV); + if (GVar && GVar->isConstant() && GVar->hasUnnamedAddr()) + return false; + + // Eventually we only need to promote functions in the exporting module that + // are referenced by a potentially exported function (i.e. one that is in the + // function index). + return true; +} + +std::string ModuleLinker::getName(const GlobalValue *SGV) { + // For locals that must be promoted to global scope, ensure that + // the promoted name uniquely identifies the copy in the original module, + // using the ID assigned during combined index creation. When importing, + // we rename all locals (not just those that are promoted) in order to + // avoid naming conflicts between locals imported from different modules. + if (SGV->hasLocalLinkage() && + (doPromoteLocalToGlobal(SGV) || isPerformingImport())) + return FunctionInfoIndex::getGlobalNameForLocal( + SGV->getName(), + ImportIndex->getModuleId(SGV->getParent()->getModuleIdentifier())); + return SGV->getName(); +} + +GlobalValue::LinkageTypes ModuleLinker::getLinkage(const GlobalValue *SGV) { + // Any local variable that is referenced by an exported function needs + // to be promoted to global scope. Since we don't currently know which + // functions reference which local variables/functions, we must treat + // all as potentially exported if this module is exporting anything. + if (isModuleExporting()) { + if (SGV->hasLocalLinkage() && doPromoteLocalToGlobal(SGV)) + return GlobalValue::ExternalLinkage; + return SGV->getLinkage(); + } + + // Otherwise, if we aren't importing, no linkage change is needed. + if (!isPerformingImport()) + return SGV->getLinkage(); + + switch (SGV->getLinkage()) { + case GlobalValue::ExternalLinkage: + // External defnitions are converted to available_externally + // definitions upon import, so that they are available for inlining + // and/or optimization, but are turned into declarations later + // during the EliminateAvailableExternally pass. + if (doImportAsDefinition(SGV) && !dyn_cast(SGV)) + return GlobalValue::AvailableExternallyLinkage; + // An imported external declaration stays external. + return SGV->getLinkage(); + + case GlobalValue::AvailableExternallyLinkage: + // An imported available_externally definition converts + // to external if imported as a declaration. + if (!doImportAsDefinition(SGV)) + return GlobalValue::ExternalLinkage; + // An imported available_externally declaration stays that way. + return SGV->getLinkage(); + + case GlobalValue::LinkOnceAnyLinkage: + case GlobalValue::LinkOnceODRLinkage: + // These both stay the same when importing the definition. + // The ThinLTO pass will eventually force-import their definitions. + return SGV->getLinkage(); + + case GlobalValue::WeakAnyLinkage: + // Can't import weak_any definitions correctly, or we might change the + // program semantics, since the linker will pick the first weak_any + // definition and importing would change the order they are seen by the + // linker. The module linking caller needs to enforce this. + assert(!doImportAsDefinition(SGV)); + // If imported as a declaration, it becomes external_weak. + return GlobalValue::ExternalWeakLinkage; + + case GlobalValue::WeakODRLinkage: + // For weak_odr linkage, there is a guarantee that all copies will be + // equivalent, so the issue described above for weak_any does not exist, + // and the definition can be imported. It can be treated similarly + // to an imported externally visible global value. + if (doImportAsDefinition(SGV) && !dyn_cast(SGV)) + return GlobalValue::AvailableExternallyLinkage; + else + return GlobalValue::ExternalLinkage; + + case GlobalValue::AppendingLinkage: + // It would be incorrect to import an appending linkage variable, + // since it would cause global constructors/destructors to be + // executed multiple times. This should have already been handled + // by linkGlobalValueProto. + llvm_unreachable("Cannot import appending linkage variable"); + + case GlobalValue::InternalLinkage: + case GlobalValue::PrivateLinkage: + // If we are promoting the local to global scope, it is handled + // similarly to a normal externally visible global. + if (doPromoteLocalToGlobal(SGV)) { + if (doImportAsDefinition(SGV) && !dyn_cast(SGV)) + return GlobalValue::AvailableExternallyLinkage; + else + return GlobalValue::ExternalLinkage; + } + // A non-promoted imported local definition stays local. + // The ThinLTO pass will eventually force-import their definitions. + return SGV->getLinkage(); + + case GlobalValue::ExternalWeakLinkage: + // External weak doesn't apply to definitions, must be a declaration. + assert(!doImportAsDefinition(SGV)); + // Linkage stays external_weak. + return SGV->getLinkage(); + + case GlobalValue::CommonLinkage: + // Linkage stays common on definitions. + // The ThinLTO pass will eventually force-import their definitions. + return SGV->getLinkage(); + } + + llvm_unreachable("unknown linkage type"); +} + +/// Loop through the global variables in the src module and merge them into the +/// dest module. +GlobalVariable * +ModuleLinker::copyGlobalVariableProto(TypeMapTy &TypeMap, + const GlobalVariable *SGVar) { + // No linking to be performed or linking from the source: simply create an + // identical version of the symbol over in the dest module... the + // initializer will be filled in later by LinkGlobalInits. + GlobalVariable *NewDGV = new GlobalVariable( + *DstM, TypeMap.get(SGVar->getType()->getElementType()), + SGVar->isConstant(), getLinkage(SGVar), /*init*/ nullptr, getName(SGVar), + /*insertbefore*/ nullptr, SGVar->getThreadLocalMode(), + SGVar->getType()->getAddressSpace()); + + return NewDGV; +} + +/// Link the function in the source module into the destination module if +/// needed, setting up mapping information. +Function *ModuleLinker::copyFunctionProto(TypeMapTy &TypeMap, + const Function *SF) { + // If there is no linkage to be performed or we are linking from the source, + // bring SF over. + return Function::Create(TypeMap.get(SF->getFunctionType()), getLinkage(SF), + getName(SF), DstM); +} + +/// Set up prototypes for any aliases that come over from the source module. +GlobalValue *ModuleLinker::copyGlobalAliasProto(TypeMapTy &TypeMap, + const GlobalAlias *SGA) { + // If we are importing and encounter a weak_any alias, or an alias to + // an object being imported as a declaration, we must import the alias + // as a declaration as well, which involves converting it to a non-alias. + // See comments in ModuleLinker::getLinkage for why we cannot import + // weak_any defintions. + if (isPerformingImport() && !doImportAsDefinition(SGA)) { + // Need to convert to declaration. All aliases must be definitions. + const GlobalValue *GVal = SGA->getBaseObject(); + GlobalValue *NewGV; + if (auto *GVar = dyn_cast(GVal)) + NewGV = copyGlobalVariableProto(TypeMap, GVar); + else { + auto *F = dyn_cast(GVal); + assert(F); + NewGV = copyFunctionProto(TypeMap, F); + } + // Set the linkage to External or ExternalWeak (see comments in + // ModuleLinker::getLinkage for why WeakAny is converted to ExternalWeak). + if (SGA->hasWeakAnyLinkage()) + NewGV->setLinkage(GlobalValue::ExternalWeakLinkage); + else + NewGV->setLinkage(GlobalValue::ExternalLinkage); + return NewGV; + } + // If there is no linkage to be performed or we're linking from the source, + // bring over SGA. + auto *Ty = TypeMap.get(SGA->getValueType()); + return GlobalAlias::create(Ty, SGA->getType()->getPointerAddressSpace(), + getLinkage(SGA), getName(SGA), DstM); +} + +static GlobalValue::VisibilityTypes +getMinVisibility(GlobalValue::VisibilityTypes A, + GlobalValue::VisibilityTypes B) { + if (A == GlobalValue::HiddenVisibility || B == GlobalValue::HiddenVisibility) + return GlobalValue::HiddenVisibility; + if (A == GlobalValue::ProtectedVisibility || + B == GlobalValue::ProtectedVisibility) + return GlobalValue::ProtectedVisibility; + return GlobalValue::DefaultVisibility; +} + +void ModuleLinker::setVisibility(GlobalValue *NewGV, const GlobalValue *SGV, + const GlobalValue *DGV) { + GlobalValue::VisibilityTypes Visibility = SGV->getVisibility(); + if (DGV) + Visibility = getMinVisibility(DGV->getVisibility(), Visibility); + // For promoted locals, mark them hidden so that they can later be + // stripped from the symbol table to reduce bloat. + if (SGV->hasLocalLinkage() && doPromoteLocalToGlobal(SGV)) + Visibility = GlobalValue::HiddenVisibility; + NewGV->setVisibility(Visibility); +} + +GlobalValue *ModuleLinker::copyGlobalValueProto(TypeMapTy &TypeMap, + const GlobalValue *SGV, + const GlobalValue *DGV) { + GlobalValue *NewGV; + if (auto *SGVar = dyn_cast(SGV)) + NewGV = copyGlobalVariableProto(TypeMap, SGVar); + else if (auto *SF = dyn_cast(SGV)) + NewGV = copyFunctionProto(TypeMap, SF); + else + NewGV = copyGlobalAliasProto(TypeMap, cast(SGV)); + copyGVAttributes(NewGV, SGV); + setVisibility(NewGV, SGV, DGV); + return NewGV; +} + +Value *ValueMaterializerTy::materializeDeclFor(Value *V) { + return ModLinker->materializeDeclFor(V); +} + +Value *ModuleLinker::materializeDeclFor(Value *V) { + auto *SGV = dyn_cast(V); + if (!SGV) return nullptr; - Function *DF = Function::Create(TypeMap.get(SF->getFunctionType()), - SF->getLinkage(), SF->getName(), DstM); - copyGVAttributes(DF, SF); + // If we are done linking global value bodies (i.e. we are performing + // metadata linking), don't link in the global value due to this + // reference, simply map it to null. + if (doneLinkingBodies()) + return nullptr; - if (Comdat *SC = SF->getComdat()) { - Comdat *DC = DstM->getOrInsertComdat(SC->getName()); - DF->setComdat(DC); + linkGlobalValueProto(SGV); + if (HasError) + return nullptr; + Value *Ret = ValueMap[SGV]; + assert(Ret); + return Ret; +} + +void ValueMaterializerTy::materializeInitFor(GlobalValue *New, + GlobalValue *Old) { + return ModLinker->materializeInitFor(New, Old); +} + +void ModuleLinker::materializeInitFor(GlobalValue *New, GlobalValue *Old) { + if (auto *F = dyn_cast(New)) { + if (!F->isDeclaration()) + return; + } else if (auto *V = dyn_cast(New)) { + if (V->hasInitializer()) + return; + } else { + auto *A = cast(New); + if (A->getAliasee()) + return; } - LazilyLinkFunctions.push_back(SF); - return DF; + if (Old->isDeclaration()) + return; + + if (isPerformingImport() && !doImportAsDefinition(Old)) + return; + + if (DoNotLinkFromSource.count(Old)) + return; + + linkGlobalValueBody(*Old); } bool ModuleLinker::getComdatLeader(Module *M, StringRef ComdatName, @@ -618,17 +1007,12 @@ bool ModuleLinker::computeResultingSelectionKind(StringRef ComdatName, getComdatLeader(SrcM, ComdatName, SrcGV)) return true; - const DataLayout *DstDL = DstM->getDataLayout(); - const DataLayout *SrcDL = SrcM->getDataLayout(); - if (!DstDL || !SrcDL) { - return emitError( - "Linking COMDATs named '" + ComdatName + - "': can't do size dependent selection without DataLayout!"); - } + const DataLayout &DstDL = DstM->getDataLayout(); + const DataLayout &SrcDL = SrcM->getDataLayout(); uint64_t DstSize = - DstDL->getTypeAllocSize(DstGV->getType()->getPointerElementType()); + DstDL.getTypeAllocSize(DstGV->getType()->getPointerElementType()); uint64_t SrcSize = - SrcDL->getTypeAllocSize(SrcGV->getType()->getPointerElementType()); + SrcDL.getTypeAllocSize(SrcGV->getType()->getPointerElementType()); if (Result == Comdat::SelectionKind::ExactMatch) { if (SrcGV->getInitializer() != DstGV->getInitializer()) return emitError("Linking COMDATs named '" + ComdatName + @@ -675,8 +1059,17 @@ bool ModuleLinker::getComdatResult(const Comdat *SrcC, bool ModuleLinker::shouldLinkFromSource(bool &LinkFromSrc, const GlobalValue &Dest, const GlobalValue &Src) { + // Should we unconditionally use the Src? + if (shouldOverrideFromSrc()) { + LinkFromSrc = true; + return false; + } + // We always have to add Src if it has appending linkage. if (Src.hasAppendingLinkage()) { + // Caller should have already determined that we can't link from source + // when importing (see comments in linkGlobalValueProto). + assert(!isPerformingImport()); LinkFromSrc = true; return false; } @@ -684,6 +1077,28 @@ bool ModuleLinker::shouldLinkFromSource(bool &LinkFromSrc, bool SrcIsDeclaration = Src.isDeclarationForLinker(); bool DestIsDeclaration = Dest.isDeclarationForLinker(); + if (isPerformingImport()) { + if (isa(&Src)) { + // For functions, LinkFromSrc iff this is the function requested + // for importing. For variables, decide below normally. + LinkFromSrc = (&Src == ImportFunction); + return false; + } + + // Check if this is an alias with an already existing definition + // in Dest, which must have come from a prior importing pass from + // the same Src module. Unlike imported function and variable + // definitions, which are imported as available_externally and are + // not definitions for the linker, that is not a valid linkage for + // imported aliases which must be definitions. Simply use the existing + // Dest copy. + if (isa(&Src) && !DestIsDeclaration) { + assert(isa(&Dest)); + LinkFromSrc = false; + return false; + } + } + if (SrcIsDeclaration) { // If Src is external or if both Src & Dest are external.. Just link the // external globals, we aren't adding anything. @@ -714,9 +1129,7 @@ bool ModuleLinker::shouldLinkFromSource(bool &LinkFromSrc, return false; } - // FIXME: Make datalayout mandatory and just use getDataLayout(). - DataLayout DL(Dest.getParent()); - + const DataLayout &DL = Dest.getParent()->getDataLayout(); uint64_t DestSize = DL.getTypeAllocSize(Dest.getType()->getElementType()); uint64_t SrcSize = DL.getTypeAllocSize(Src.getType()->getElementType()); LinkFromSrc = SrcSize > DestSize; @@ -909,54 +1322,57 @@ void ModuleLinker::upgradeMismatchedGlobals() { /// Return true on error. bool ModuleLinker::linkAppendingVarProto(GlobalVariable *DstGV, const GlobalVariable *SrcGV) { + ArrayType *SrcTy = + cast(TypeMap.get(SrcGV->getType()->getElementType())); + Type *EltTy = SrcTy->getElementType(); - if (!SrcGV->hasAppendingLinkage() || !DstGV->hasAppendingLinkage()) - return emitError("Linking globals named '" + SrcGV->getName() + - "': can only link appending global with another appending global!"); + uint64_t NewSize = SrcTy->getNumElements(); + if (DstGV) { + ArrayType *DstTy = cast(DstGV->getType()->getElementType()); + NewSize += DstTy->getNumElements(); - ArrayType *DstTy = cast(DstGV->getType()->getElementType()); - ArrayType *SrcTy = - cast(TypeMap.get(SrcGV->getType()->getElementType())); - Type *EltTy = DstTy->getElementType(); + if (!SrcGV->hasAppendingLinkage() || !DstGV->hasAppendingLinkage()) + return emitError( + "Linking globals named '" + SrcGV->getName() + + "': can only link appending global with another appending global!"); - // Check to see that they two arrays agree on type. - if (EltTy != SrcTy->getElementType()) - return emitError("Appending variables with different element types!"); - if (DstGV->isConstant() != SrcGV->isConstant()) - return emitError("Appending variables linked with different const'ness!"); + // Check to see that they two arrays agree on type. + if (EltTy != DstTy->getElementType()) + return emitError("Appending variables with different element types!"); + if (DstGV->isConstant() != SrcGV->isConstant()) + return emitError("Appending variables linked with different const'ness!"); - if (DstGV->getAlignment() != SrcGV->getAlignment()) - return emitError( - "Appending variables with different alignment need to be linked!"); + if (DstGV->getAlignment() != SrcGV->getAlignment()) + return emitError( + "Appending variables with different alignment need to be linked!"); - if (DstGV->getVisibility() != SrcGV->getVisibility()) - return emitError( - "Appending variables with different visibility need to be linked!"); + if (DstGV->getVisibility() != SrcGV->getVisibility()) + return emitError( + "Appending variables with different visibility need to be linked!"); - if (DstGV->hasUnnamedAddr() != SrcGV->hasUnnamedAddr()) - return emitError( - "Appending variables with different unnamed_addr need to be linked!"); + if (DstGV->hasUnnamedAddr() != SrcGV->hasUnnamedAddr()) + return emitError( + "Appending variables with different unnamed_addr need to be linked!"); - if (StringRef(DstGV->getSection()) != SrcGV->getSection()) - return emitError( + if (StringRef(DstGV->getSection()) != SrcGV->getSection()) + return emitError( "Appending variables with different section name need to be linked!"); + } - uint64_t NewSize = DstTy->getNumElements() + SrcTy->getNumElements(); ArrayType *NewType = ArrayType::get(EltTy, NewSize); // Create the new global variable. - GlobalVariable *NG = - new GlobalVariable(*DstGV->getParent(), NewType, SrcGV->isConstant(), - DstGV->getLinkage(), /*init*/nullptr, /*name*/"", DstGV, - DstGV->getThreadLocalMode(), - DstGV->getType()->getAddressSpace()); + GlobalVariable *NG = new GlobalVariable( + *DstM, NewType, SrcGV->isConstant(), SrcGV->getLinkage(), + /*init*/ nullptr, /*name*/ "", DstGV, SrcGV->getThreadLocalMode(), + SrcGV->getType()->getAddressSpace()); // Propagate alignment, visibility and section info. - copyGVAttributes(NG, DstGV); + copyGVAttributes(NG, SrcGV); AppendingVarInfo AVI; AVI.NewGV = NG; - AVI.DstInit = DstGV->getInitializer(); + AVI.DstInit = DstGV ? DstGV->getInitializer() : nullptr; AVI.SrcInit = SrcGV->getInitializer(); AppendingVars.push_back(AVI); @@ -964,8 +1380,10 @@ bool ModuleLinker::linkAppendingVarProto(GlobalVariable *DstGV, // global. ValueMap[SrcGV] = ConstantExpr::getBitCast(NG, TypeMap.get(SrcGV->getType())); - DstGV->replaceAllUsesWith(ConstantExpr::getBitCast(NG, DstGV->getType())); - DstGV->eraseFromParent(); + if (DstGV) { + DstGV->replaceAllUsesWith(ConstantExpr::getBitCast(NG, DstGV->getType())); + DstGV->eraseFromParent(); + } // Track the source variable so we don't try to link it. DoNotLinkFromSource.insert(SrcGV); @@ -977,13 +1395,21 @@ bool ModuleLinker::linkGlobalValueProto(GlobalValue *SGV) { GlobalValue *DGV = getLinkedToGlobal(SGV); // Handle the ultra special appending linkage case first. - if (DGV && DGV->hasAppendingLinkage()) - return linkAppendingVarProto(cast(DGV), + assert(!DGV || SGV->hasAppendingLinkage() == DGV->hasAppendingLinkage()); + if (SGV->hasAppendingLinkage() && isPerformingImport()) { + // Don't want to append to global_ctors list, for example, when we + // are importing for ThinLTO, otherwise the global ctors and dtors + // get executed multiple times for local variables (the latter causing + // double frees). + DoNotLinkFromSource.insert(SGV); + return false; + } + if (SGV->hasAppendingLinkage()) + return linkAppendingVarProto(cast_or_null(DGV), cast(SGV)); bool LinkFromSrc = true; Comdat *C = nullptr; - GlobalValue::VisibilityTypes Visibility = SGV->getVisibility(); bool HasUnnamedAddr = SGV->hasUnnamedAddr(); if (const Comdat *SC = SGV->getComdat()) { @@ -1007,39 +1433,25 @@ bool ModuleLinker::linkGlobalValueProto(GlobalValue *SGV) { ConstantExpr::getBitCast(DGV, TypeMap.get(SGV->getType())); } - if (DGV) { - Visibility = isLessConstraining(Visibility, DGV->getVisibility()) - ? DGV->getVisibility() - : Visibility; + if (DGV) HasUnnamedAddr = HasUnnamedAddr && DGV->hasUnnamedAddr(); - } - - if (!LinkFromSrc && !DGV) - return false; GlobalValue *NewGV; - if (!LinkFromSrc) { + if (!LinkFromSrc && DGV) { NewGV = DGV; + // When linking from source we setVisibility from copyGlobalValueProto. + setVisibility(NewGV, SGV, DGV); } else { - if (auto *SGVar = dyn_cast(SGV)) - NewGV = linkGlobalVariableProto(SGVar); - else if (auto *SF = dyn_cast(SGV)) - NewGV = linkFunctionProto(SF, DGV); - else - NewGV = linkGlobalAliasProto(cast(SGV)); - } - - if (!NewGV) - return false; + NewGV = copyGlobalValueProto(TypeMap, SGV, DGV); - if (NewGV != DGV) - copyGVAttributes(NewGV, SGV); + if (isPerformingImport() && !doImportAsDefinition(SGV)) + DoNotLinkFromSource.insert(SGV); + } NewGV->setUnnamedAddr(HasUnnamedAddr); - NewGV->setVisibility(Visibility); if (auto *NewGO = dyn_cast(NewGV)) { - if (C) + if (C && LinkFromSrc) NewGO->setComdat(C); if (DGV && DGV->hasCommonLinkage() && SGV->hasCommonLinkage()) @@ -1066,49 +1478,6 @@ bool ModuleLinker::linkGlobalValueProto(GlobalValue *SGV) { return false; } -/// Loop through the global variables in the src module and merge them into the -/// dest module. -GlobalValue * -ModuleLinker::linkGlobalVariableProto(const GlobalVariable *SGVar) { - // No linking to be performed or linking from the source: simply create an - // identical version of the symbol over in the dest module... the - // initializer will be filled in later by LinkGlobalInits. - GlobalVariable *NewDGV = new GlobalVariable( - *DstM, TypeMap.get(SGVar->getType()->getElementType()), - SGVar->isConstant(), SGVar->getLinkage(), /*init*/ nullptr, - SGVar->getName(), /*insertbefore*/ nullptr, SGVar->getThreadLocalMode(), - SGVar->getType()->getAddressSpace()); - - return NewDGV; -} - -/// Link the function in the source module into the destination module if -/// needed, setting up mapping information. -GlobalValue *ModuleLinker::linkFunctionProto(const Function *SF, - GlobalValue *DGV) { - // If the function is to be lazily linked, don't create it just yet. - // The ValueMaterializerTy will deal with creating it if it's used. - if (!DGV && (SF->hasLocalLinkage() || SF->hasLinkOnceLinkage() || - SF->hasAvailableExternallyLinkage())) { - DoNotLinkFromSource.insert(SF); - return nullptr; - } - - // If there is no linkage to be performed or we are linking from the source, - // bring SF over. - return Function::Create(TypeMap.get(SF->getFunctionType()), SF->getLinkage(), - SF->getName(), DstM); -} - -/// Set up prototypes for any aliases that come over from the source module. -GlobalValue *ModuleLinker::linkGlobalAliasProto(const GlobalAlias *SGA) { - // If there is no linkage to be performed or we're linking from the source, - // bring over SGA. - auto *PTy = cast(TypeMap.get(SGA->getType())); - return GlobalAlias::create(PTy->getElementType(), PTy->getAddressSpace(), - SGA->getLinkage(), SGA->getName(), DstM); -} - static void getArrayElements(const Constant *C, SmallVectorImpl &Dest) { unsigned NumElements = cast(C->getType())->getNumElements(); @@ -1117,10 +1486,11 @@ static void getArrayElements(const Constant *C, Dest.push_back(C->getAggregateElement(i)); } -void ModuleLinker::linkAppendingVarInit(const AppendingVarInfo &AVI) { +void ModuleLinker::linkAppendingVarInit(AppendingVarInfo &AVI) { // Merge the initializer. SmallVector DstElements; - getArrayElements(AVI.DstInit, DstElements); + if (AVI.DstInit) + getArrayElements(AVI.DstInit, DstElements); SmallVector SrcElements; getArrayElements(AVI.SrcInit, SrcElements); @@ -1134,16 +1504,26 @@ void ModuleLinker::linkAppendingVarInit(const AppendingVarInfo &AVI) { for (auto *V : SrcElements) { if (IsNewStructor) { - Constant *Key = V->getAggregateElement(2); + auto *Key = + dyn_cast(V->getAggregateElement(2)->stripPointerCasts()); if (DoNotLinkFromSource.count(Key)) continue; } DstElements.push_back( - MapValue(V, ValueMap, RF_None, &TypeMap, &ValMaterializer)); + MapValue(V, ValueMap, RF_MoveDistinctMDs, &TypeMap, &ValMaterializer)); } - if (IsNewStructor) { + if (DstElements.size() != NewType->getNumElements()) { NewType = ArrayType::get(NewType->getElementType(), DstElements.size()); - AVI.NewGV->mutateType(PointerType::get(NewType, 0)); + GlobalVariable *Old = AVI.NewGV; + GlobalVariable *NG = new GlobalVariable( + *DstM, NewType, Old->isConstant(), Old->getLinkage(), /*init*/ nullptr, + /*name*/ "", Old, Old->getThreadLocalMode(), + Old->getType()->getAddressSpace()); + copyGVAttributes(NG, Old); + AVI.NewGV->replaceAllUsesWith( + ConstantExpr::getBitCast(NG, AVI.NewGV->getType())); + AVI.NewGV->eraseFromParent(); + AVI.NewGV = NG; } AVI.NewGV->setInitializer(ConstantArray::get(NewType, DstElements)); @@ -1151,84 +1531,126 @@ void ModuleLinker::linkAppendingVarInit(const AppendingVarInfo &AVI) { /// Update the initializers in the Dest module now that all globals that may be /// referenced are in Dest. -void ModuleLinker::linkGlobalInits() { - // Loop over all of the globals in the src module, mapping them over as we go - for (Module::const_global_iterator I = SrcM->global_begin(), - E = SrcM->global_end(); I != E; ++I) { - - // Only process initialized GV's or ones not already in dest. - if (!I->hasInitializer() || DoNotLinkFromSource.count(I)) continue; - - // Grab destination global variable. - GlobalVariable *DGV = cast(ValueMap[I]); - // Figure out what the initializer looks like in the dest module. - DGV->setInitializer(MapValue(I->getInitializer(), ValueMap, - RF_None, &TypeMap, &ValMaterializer)); - } +void ModuleLinker::linkGlobalInit(GlobalVariable &Dst, GlobalVariable &Src) { + // Figure out what the initializer looks like in the dest module. + Dst.setInitializer(MapValue(Src.getInitializer(), ValueMap, + RF_MoveDistinctMDs, &TypeMap, &ValMaterializer)); } /// Copy the source function over into the dest function and fix up references /// to values. At this point we know that Dest is an external function, and /// that Src is not. -void ModuleLinker::linkFunctionBody(Function *Dst, Function *Src) { - assert(Src && Dst && Dst->isDeclaration() && !Src->isDeclaration()); +bool ModuleLinker::linkFunctionBody(Function &Dst, Function &Src) { + assert(Dst.isDeclaration() && !Src.isDeclaration()); + + // Materialize if needed. + if (std::error_code EC = Src.materialize()) + return emitError(EC.message()); + + // Link in the prefix data. + if (Src.hasPrefixData()) + Dst.setPrefixData(MapValue(Src.getPrefixData(), ValueMap, + RF_MoveDistinctMDs, &TypeMap, &ValMaterializer)); + + // Link in the prologue data. + if (Src.hasPrologueData()) + Dst.setPrologueData(MapValue(Src.getPrologueData(), ValueMap, + RF_MoveDistinctMDs, &TypeMap, + &ValMaterializer)); + + // Link in the personality function. + if (Src.hasPersonalityFn()) + Dst.setPersonalityFn(MapValue(Src.getPersonalityFn(), ValueMap, + RF_MoveDistinctMDs, &TypeMap, + &ValMaterializer)); // Go through and convert function arguments over, remembering the mapping. - Function::arg_iterator DI = Dst->arg_begin(); - for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end(); - I != E; ++I, ++DI) { - DI->setName(I->getName()); // Copy the name over. + Function::arg_iterator DI = Dst.arg_begin(); + for (Argument &Arg : Src.args()) { + DI->setName(Arg.getName()); // Copy the name over. // Add a mapping to our mapping. - ValueMap[I] = DI; + ValueMap[&Arg] = &*DI; + ++DI; } + // Copy over the metadata attachments. + SmallVector, 8> MDs; + Src.getAllMetadata(MDs); + for (const auto &I : MDs) + Dst.setMetadata(I.first, MapMetadata(I.second, ValueMap, RF_MoveDistinctMDs, + &TypeMap, &ValMaterializer)); + // Splice the body of the source function into the dest function. - Dst->getBasicBlockList().splice(Dst->end(), Src->getBasicBlockList()); + Dst.getBasicBlockList().splice(Dst.end(), Src.getBasicBlockList()); // At this point, all of the instructions and values of the function are now // copied over. The only problem is that they are still referencing values in // the Source function as operands. Loop through all of the operands of the // functions and patch them up to point to the local versions. - for (Function::iterator BB = Dst->begin(), BE = Dst->end(); BB != BE; ++BB) - for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) - RemapInstruction(I, ValueMap, RF_IgnoreMissingEntries, &TypeMap, + for (BasicBlock &BB : Dst) + for (Instruction &I : BB) + RemapInstruction(&I, ValueMap, + RF_IgnoreMissingEntries | RF_MoveDistinctMDs, &TypeMap, &ValMaterializer); // There is no need to map the arguments anymore. - for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end(); - I != E; ++I) - ValueMap.erase(I); + for (Argument &Arg : Src.args()) + ValueMap.erase(&Arg); + Src.dematerialize(); + return false; } -/// Insert all of the aliases in Src into the Dest module. -void ModuleLinker::linkAliasBodies() { - for (Module::alias_iterator I = SrcM->alias_begin(), E = SrcM->alias_end(); - I != E; ++I) { - if (DoNotLinkFromSource.count(I)) - continue; - if (Constant *Aliasee = I->getAliasee()) { - GlobalAlias *DA = cast(ValueMap[I]); - Constant *Val = - MapValue(Aliasee, ValueMap, RF_None, &TypeMap, &ValMaterializer); - DA->setAliasee(Val); +void ModuleLinker::linkAliasBody(GlobalAlias &Dst, GlobalAlias &Src) { + Constant *Aliasee = Src.getAliasee(); + Constant *Val = MapValue(Aliasee, ValueMap, RF_MoveDistinctMDs, &TypeMap, + &ValMaterializer); + Dst.setAliasee(Val); +} + +bool ModuleLinker::linkGlobalValueBody(GlobalValue &Src) { + Value *Dst = ValueMap[&Src]; + assert(Dst); + if (const Comdat *SC = Src.getComdat()) { + // To ensure that we don't generate an incomplete comdat group, + // we must materialize and map in any other members that are not + // yet materialized in Dst, which also ensures their definitions + // are linked in. Otherwise, linkonce and other lazy linked GVs will + // not be materialized if they aren't referenced. + for (auto *SGV : ComdatMembers[SC]) { + auto *DGV = cast_or_null(ValueMap[SGV]); + if (DGV && !DGV->isDeclaration()) + continue; + MapValue(SGV, ValueMap, RF_MoveDistinctMDs, &TypeMap, &ValMaterializer); } } + if (shouldInternalizeLinkedSymbols()) + if (auto *DGV = dyn_cast(Dst)) + DGV->setLinkage(GlobalValue::InternalLinkage); + if (auto *F = dyn_cast(&Src)) + return linkFunctionBody(cast(*Dst), *F); + if (auto *GVar = dyn_cast(&Src)) { + linkGlobalInit(cast(*Dst), *GVar); + return false; + } + linkAliasBody(cast(*Dst), cast(Src)); + return false; } /// Insert all of the named MDNodes in Src into the Dest module. void ModuleLinker::linkNamedMDNodes() { const NamedMDNode *SrcModFlags = SrcM->getModuleFlagsMetadata(); - for (Module::const_named_metadata_iterator I = SrcM->named_metadata_begin(), - E = SrcM->named_metadata_end(); I != E; ++I) { + for (const NamedMDNode &NMD : SrcM->named_metadata()) { // Don't link module flags here. Do them separately. - if (&*I == SrcModFlags) continue; - NamedMDNode *DestNMD = DstM->getOrInsertNamedMetadata(I->getName()); + if (&NMD == SrcModFlags) + continue; + NamedMDNode *DestNMD = DstM->getOrInsertNamedMetadata(NMD.getName()); // Add Src elements into Dest node. - for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) - DestNMD->addOperand(MapValue(I->getOperand(i), ValueMap, - RF_None, &TypeMap, &ValMaterializer)); + for (const MDNode *op : NMD.operands()) + DestNMD->addOperand(MapMetadata( + op, ValueMap, RF_MoveDistinctMDs | RF_NullMapMissingGlobalValues, + &TypeMap, &ValMaterializer)); } } @@ -1249,17 +1671,17 @@ bool ModuleLinker::linkModuleFlagsMetadata() { } // First build a map of the existing module flags and requirements. - DenseMap Flags; + DenseMap> Flags; SmallSetVector Requirements; for (unsigned I = 0, E = DstModFlags->getNumOperands(); I != E; ++I) { MDNode *Op = DstModFlags->getOperand(I); - ConstantInt *Behavior = cast(Op->getOperand(0)); + ConstantInt *Behavior = mdconst::extract(Op->getOperand(0)); MDString *ID = cast(Op->getOperand(1)); if (Behavior->getZExtValue() == Module::Require) { Requirements.insert(cast(Op->getOperand(2))); } else { - Flags[ID] = Op; + Flags[ID] = std::make_pair(Op, I); } } @@ -1268,9 +1690,12 @@ bool ModuleLinker::linkModuleFlagsMetadata() { bool HasErr = false; for (unsigned I = 0, E = SrcModFlags->getNumOperands(); I != E; ++I) { MDNode *SrcOp = SrcModFlags->getOperand(I); - ConstantInt *SrcBehavior = cast(SrcOp->getOperand(0)); + ConstantInt *SrcBehavior = + mdconst::extract(SrcOp->getOperand(0)); MDString *ID = cast(SrcOp->getOperand(1)); - MDNode *DstOp = Flags.lookup(ID); + MDNode *DstOp; + unsigned DstIndex; + std::tie(DstOp, DstIndex) = Flags.lookup(ID); unsigned SrcBehaviorValue = SrcBehavior->getZExtValue(); // If this is a requirement, add it and continue. @@ -1285,13 +1710,14 @@ bool ModuleLinker::linkModuleFlagsMetadata() { // If there is no existing flag with this ID, just add it. if (!DstOp) { - Flags[ID] = SrcOp; + Flags[ID] = std::make_pair(SrcOp, DstModFlags->getNumOperands()); DstModFlags->addOperand(SrcOp); continue; } // Otherwise, perform a merge. - ConstantInt *DstBehavior = cast(DstOp->getOperand(0)); + ConstantInt *DstBehavior = + mdconst::extract(DstOp->getOperand(0)); unsigned DstBehaviorValue = DstBehavior->getZExtValue(); // If either flag has override behavior, handle it first. @@ -1305,8 +1731,8 @@ bool ModuleLinker::linkModuleFlagsMetadata() { continue; } else if (SrcBehaviorValue == Module::Override) { // Update the destination flag to that of the source. - DstOp->replaceOperandWith(0, SrcBehavior); - DstOp->replaceOperandWith(2, SrcOp->getOperand(2)); + DstModFlags->setOperand(DstIndex, SrcOp); + Flags[ID].first = SrcOp; continue; } @@ -1317,6 +1743,13 @@ bool ModuleLinker::linkModuleFlagsMetadata() { continue; } + auto replaceDstValue = [&](MDNode *New) { + Metadata *FlagOps[] = {DstOp->getOperand(0), ID, New}; + MDNode *Flag = MDNode::get(DstM->getContext(), FlagOps); + DstModFlags->setOperand(DstIndex, Flag); + Flags[ID].first = Flag; + }; + // Perform the merge for standard behavior types. switch (SrcBehaviorValue) { case Module::Require: @@ -1340,29 +1773,23 @@ bool ModuleLinker::linkModuleFlagsMetadata() { case Module::Append: { MDNode *DstValue = cast(DstOp->getOperand(2)); MDNode *SrcValue = cast(SrcOp->getOperand(2)); - unsigned NumOps = DstValue->getNumOperands() + SrcValue->getNumOperands(); - Value **VP, **Values = VP = new Value*[NumOps]; - for (unsigned i = 0, e = DstValue->getNumOperands(); i != e; ++i, ++VP) - *VP = DstValue->getOperand(i); - for (unsigned i = 0, e = SrcValue->getNumOperands(); i != e; ++i, ++VP) - *VP = SrcValue->getOperand(i); - DstOp->replaceOperandWith(2, MDNode::get(DstM->getContext(), - ArrayRef(Values, - NumOps))); - delete[] Values; + SmallVector MDs; + MDs.reserve(DstValue->getNumOperands() + SrcValue->getNumOperands()); + MDs.append(DstValue->op_begin(), DstValue->op_end()); + MDs.append(SrcValue->op_begin(), SrcValue->op_end()); + + replaceDstValue(MDNode::get(DstM->getContext(), MDs)); break; } case Module::AppendUnique: { - SmallSetVector Elts; + SmallSetVector Elts; MDNode *DstValue = cast(DstOp->getOperand(2)); MDNode *SrcValue = cast(SrcOp->getOperand(2)); - for (unsigned i = 0, e = DstValue->getNumOperands(); i != e; ++i) - Elts.insert(DstValue->getOperand(i)); - for (unsigned i = 0, e = SrcValue->getNumOperands(); i != e; ++i) - Elts.insert(SrcValue->getOperand(i)); - DstOp->replaceOperandWith(2, MDNode::get(DstM->getContext(), - ArrayRef(Elts.begin(), - Elts.end()))); + Elts.insert(DstValue->op_begin(), DstValue->op_end()); + Elts.insert(SrcValue->op_begin(), SrcValue->op_end()); + + replaceDstValue(MDNode::get(DstM->getContext(), + makeArrayRef(Elts.begin(), Elts.end()))); break; } } @@ -1372,9 +1799,9 @@ bool ModuleLinker::linkModuleFlagsMetadata() { for (unsigned I = 0, E = Requirements.size(); I != E; ++I) { MDNode *Requirement = Requirements[I]; MDString *Flag = cast(Requirement->getOperand(0)); - Value *ReqValue = Requirement->getOperand(1); + Metadata *ReqValue = Requirement->getOperand(1); - MDNode *Op = Flags[Flag]; + MDNode *Op = Flags[Flag].first; if (!Op || Op->getOperand(2) != ReqValue) { HasErr |= emitError("linking module flags '" + Flag->getString() + "': does not have the required value"); @@ -1385,35 +1812,91 @@ bool ModuleLinker::linkModuleFlagsMetadata() { return HasErr; } +// This function returns true if the triples match. +static bool triplesMatch(const Triple &T0, const Triple &T1) { + // If vendor is apple, ignore the version number. + if (T0.getVendor() == Triple::Apple) + return T0.getArch() == T1.getArch() && + T0.getSubArch() == T1.getSubArch() && + T0.getVendor() == T1.getVendor() && + T0.getOS() == T1.getOS(); + + return T0 == T1; +} + +// This function returns the merged triple. +static std::string mergeTriples(const Triple &SrcTriple, const Triple &DstTriple) { + // If vendor is apple, pick the triple with the larger version number. + if (SrcTriple.getVendor() == Triple::Apple) + if (DstTriple.isOSVersionLT(SrcTriple)) + return SrcTriple.str(); + + return DstTriple.str(); +} + +bool ModuleLinker::linkIfNeeded(GlobalValue &GV) { + GlobalValue *DGV = getLinkedToGlobal(&GV); + + if (shouldLinkOnlyNeeded() && !(DGV && DGV->isDeclaration())) + return false; + + if (DGV && !GV.hasLocalLinkage()) { + GlobalValue::VisibilityTypes Visibility = + getMinVisibility(DGV->getVisibility(), GV.getVisibility()); + DGV->setVisibility(Visibility); + GV.setVisibility(Visibility); + } + + if (const Comdat *SC = GV.getComdat()) { + bool LinkFromSrc; + Comdat::SelectionKind SK; + std::tie(SK, LinkFromSrc) = ComdatsChosen[SC]; + if (!LinkFromSrc) { + DoNotLinkFromSource.insert(&GV); + return false; + } + } + + if (!DGV && !shouldOverrideFromSrc() && + (GV.hasLocalLinkage() || GV.hasLinkOnceLinkage() || + GV.hasAvailableExternallyLinkage())) { + return false; + } + MapValue(&GV, ValueMap, RF_MoveDistinctMDs, &TypeMap, &ValMaterializer); + return HasError; +} + bool ModuleLinker::run() { assert(DstM && "Null destination module"); assert(SrcM && "Null source module"); // Inherit the target data from the source module if the destination module // doesn't have one already. - if (!DstM->getDataLayout() && SrcM->getDataLayout()) + if (DstM->getDataLayout().isDefault()) DstM->setDataLayout(SrcM->getDataLayout()); - // Copy the target triple from the source to dest if the dest's is empty. - if (DstM->getTargetTriple().empty() && !SrcM->getTargetTriple().empty()) - DstM->setTargetTriple(SrcM->getTargetTriple()); - - if (SrcM->getDataLayout() && DstM->getDataLayout() && - *SrcM->getDataLayout() != *DstM->getDataLayout()) { + if (SrcM->getDataLayout() != DstM->getDataLayout()) { emitWarning("Linking two modules of different data layouts: '" + SrcM->getModuleIdentifier() + "' is '" + SrcM->getDataLayoutStr() + "' whereas '" + DstM->getModuleIdentifier() + "' is '" + DstM->getDataLayoutStr() + "'\n"); } - if (!SrcM->getTargetTriple().empty() && - DstM->getTargetTriple() != SrcM->getTargetTriple()) { + + // Copy the target triple from the source to dest if the dest's is empty. + if (DstM->getTargetTriple().empty() && !SrcM->getTargetTriple().empty()) + DstM->setTargetTriple(SrcM->getTargetTriple()); + + Triple SrcTriple(SrcM->getTargetTriple()), DstTriple(DstM->getTargetTriple()); + + if (!SrcM->getTargetTriple().empty() && !triplesMatch(SrcTriple, DstTriple)) emitWarning("Linking two modules of different target triples: " + SrcM->getModuleIdentifier() + "' is '" + SrcM->getTargetTriple() + "' whereas '" + DstM->getModuleIdentifier() + "' is '" + DstM->getTargetTriple() + "'\n"); - } + + DstM->setTargetTriple(mergeTriples(SrcTriple, DstTriple)); // Append the module inline asm string. if (!SrcM->getModuleInlineAsm().empty()) { @@ -1442,63 +1925,47 @@ bool ModuleLinker::run() { // Upgrade mismatched global arrays. upgradeMismatchedGlobals(); + for (GlobalVariable &GV : SrcM->globals()) + if (const Comdat *SC = GV.getComdat()) + ComdatMembers[SC].push_back(&GV); + + for (Function &SF : *SrcM) + if (const Comdat *SC = SF.getComdat()) + ComdatMembers[SC].push_back(&SF); + + for (GlobalAlias &GA : SrcM->aliases()) + if (const Comdat *SC = GA.getComdat()) + ComdatMembers[SC].push_back(&GA); + // Insert all of the globals in src into the DstM module... without linking // initializers (which could refer to functions not yet mapped over). - for (Module::global_iterator I = SrcM->global_begin(), - E = SrcM->global_end(); I != E; ++I) - if (linkGlobalValueProto(I)) + for (GlobalVariable &GV : SrcM->globals()) + if (linkIfNeeded(GV)) return true; - // Link the functions together between the two modules, without doing function - // bodies... this just adds external function prototypes to the DstM - // function... We do this so that when we begin processing function bodies, - // all of the global values that may be referenced are available in our - // ValueMap. - for (Module::iterator I = SrcM->begin(), E = SrcM->end(); I != E; ++I) - if (linkGlobalValueProto(I)) + for (Function &SF : *SrcM) + if (linkIfNeeded(SF)) return true; - // If there were any aliases, link them now. - for (Module::alias_iterator I = SrcM->alias_begin(), - E = SrcM->alias_end(); I != E; ++I) - if (linkGlobalValueProto(I)) + for (GlobalAlias &GA : SrcM->aliases()) + if (linkIfNeeded(GA)) return true; - for (unsigned i = 0, e = AppendingVars.size(); i != e; ++i) - linkAppendingVarInit(AppendingVars[i]); + for (AppendingVarInfo &AppendingVar : AppendingVars) + linkAppendingVarInit(AppendingVar); - // Link in the function bodies that are defined in the source module into - // DstM. - for (Module::iterator SF = SrcM->begin(), E = SrcM->end(); SF != E; ++SF) { - // Skip if not linking from source. - if (DoNotLinkFromSource.count(SF)) continue; - - Function *DF = cast(ValueMap[SF]); - - // Link in the prefix data. - if (SF->hasPrefixData()) - DF->setPrefixData(MapValue( - SF->getPrefixData(), ValueMap, RF_None, &TypeMap, &ValMaterializer)); - - // Link in the prologue data. - if (SF->hasPrologueData()) - DF->setPrologueData(MapValue( - SF->getPrologueData(), ValueMap, RF_None, &TypeMap, &ValMaterializer)); - - // Materialize if needed. - if (std::error_code EC = SF->materialize()) - return emitError(EC.message()); - - // Skip if no body (function is external). - if (SF->isDeclaration()) + for (const auto &Entry : DstM->getComdatSymbolTable()) { + const Comdat &C = Entry.getValue(); + if (C.getSelectionKind() == Comdat::Any) continue; - - linkFunctionBody(DF, SF); - SF->Dematerialize(); + const GlobalValue *GV = SrcM->getNamedValue(C.getName()); + if (GV) + MapValue(GV, ValueMap, RF_MoveDistinctMDs, &TypeMap, &ValMaterializer); } - // Resolve all uses of aliases with aliasees. - linkAliasBodies(); + // Note that we are done linking global value bodies. This prevents + // metadata linking from creating new references. + DoneLinkingBodies = true; // Remap all of the named MDNodes in Src into the DstM module. We do this // after linking GlobalValues so that MDNodes that reference GlobalValues @@ -1509,32 +1976,6 @@ bool ModuleLinker::run() { if (linkModuleFlagsMetadata()) return true; - // Update the initializers in the DstM module now that all globals that may - // be referenced are in DstM. - linkGlobalInits(); - - // Process vector of lazily linked in functions. - while (!LazilyLinkFunctions.empty()) { - Function *SF = LazilyLinkFunctions.back(); - LazilyLinkFunctions.pop_back(); - - Function *DF = cast(ValueMap[SF]); - if (SF->hasPrefixData()) { - // Link in the prefix data. - DF->setPrefixData(MapValue(SF->getPrefixData(), ValueMap, RF_None, - &TypeMap, &ValMaterializer)); - } - - // Materialize if needed. - if (std::error_code EC = SF->materialize()) - return emitError(EC.message()); - - // Link in function body. - assert(!SF->isDeclaration()); - linkFunctionBody(DF, SF); - SF->Dematerialize(); - } - return false; } @@ -1593,8 +2034,15 @@ bool Linker::StructTypeKeyInfo::isEqual(const StructType *LHS, void Linker::IdentifiedStructTypeSet::addNonOpaque(StructType *Ty) { assert(!Ty->isOpaque()); - bool &Entry = NonOpaqueStructTypes[Ty]; - Entry = true; + NonOpaqueStructTypes.insert(Ty); +} + +void Linker::IdentifiedStructTypeSet::switchToNonOpaque(StructType *Ty) { + assert(!Ty->isOpaque()); + NonOpaqueStructTypes.insert(Ty); + bool Removed = OpaqueStructTypes.erase(Ty); + (void)Removed; + assert(Removed); } void Linker::IdentifiedStructTypeSet::addOpaque(StructType *Ty) { @@ -1609,7 +2057,7 @@ Linker::IdentifiedStructTypeSet::findNonOpaque(ArrayRef ETypes, auto I = NonOpaqueStructTypes.find_as(Key); if (I == NonOpaqueStructTypes.end()) return nullptr; - return I->first; + return *I; } bool Linker::IdentifiedStructTypeSet::hasType(StructType *Ty) { @@ -1618,7 +2066,7 @@ bool Linker::IdentifiedStructTypeSet::hasType(StructType *Ty) { auto I = NonOpaqueStructTypes.find(Ty); if (I == NonOpaqueStructTypes.end()) return false; - return I->first == Ty; + return *I == Ty; } void Linker::init(Module *M, DiagnosticHandlerFunction DiagnosticHandler) { @@ -1645,18 +2093,23 @@ Linker::Linker(Module *M) { }); } -Linker::~Linker() { -} - void Linker::deleteModule() { delete Composite; Composite = nullptr; } -bool Linker::linkInModule(Module *Src) { +bool Linker::linkInModule(Module *Src, unsigned Flags, + const FunctionInfoIndex *Index, + Function *FuncToImport) { ModuleLinker TheLinker(Composite, IdentifiedStructTypes, Src, - DiagnosticHandler); - return TheLinker.run(); + DiagnosticHandler, Flags, Index, FuncToImport); + bool RetCode = TheLinker.run(); + Composite->dropTriviallyDeadConstantArrays(); + return RetCode; +} + +void Linker::setModule(Module *Dst) { + init(Dst, DiagnosticHandler); } //===----------------------------------------------------------------------===// @@ -1669,14 +2122,15 @@ bool Linker::linkInModule(Module *Src) { /// Upon failure, the Dest module could be in a modified state, and shouldn't be /// relied on to be consistent. bool Linker::LinkModules(Module *Dest, Module *Src, - DiagnosticHandlerFunction DiagnosticHandler) { + DiagnosticHandlerFunction DiagnosticHandler, + unsigned Flags) { Linker L(Dest, DiagnosticHandler); - return L.linkInModule(Src); + return L.linkInModule(Src, Flags); } -bool Linker::LinkModules(Module *Dest, Module *Src) { +bool Linker::LinkModules(Module *Dest, Module *Src, unsigned Flags) { Linker L(Dest); - return L.linkInModule(Src); + return L.linkInModule(Src, Flags); } //===----------------------------------------------------------------------===// @@ -1684,7 +2138,7 @@ bool Linker::LinkModules(Module *Dest, Module *Src) { //===----------------------------------------------------------------------===// LLVMBool LLVMLinkModules(LLVMModuleRef Dest, LLVMModuleRef Src, - LLVMLinkerMode Mode, char **OutMessages) { + LLVMLinkerMode Unused, char **OutMessages) { Module *D = unwrap(Dest); std::string Message; raw_string_ostream Stream(Message); @@ -1693,7 +2147,9 @@ LLVMBool LLVMLinkModules(LLVMModuleRef Dest, LLVMModuleRef Src, LLVMBool Result = Linker::LinkModules( D, unwrap(Src), [&](const DiagnosticInfo &DI) { DI.print(DP); }); - if (OutMessages && Result) + if (OutMessages && Result) { + Stream.flush(); *OutMessages = strdup(Message.c_str()); + } return Result; }