diff options
Diffstat (limited to 'lib/Linker/LinkModules.cpp')
| -rw-r--r-- | lib/Linker/LinkModules.cpp | 1816 |
1 files changed, 742 insertions, 1074 deletions
diff --git a/lib/Linker/LinkModules.cpp b/lib/Linker/LinkModules.cpp index f372db2403..d77062772e 100644 --- a/lib/Linker/LinkModules.cpp +++ b/lib/Linker/LinkModules.cpp @@ -9,337 +9,404 @@ // // This file implements the LLVM module linker. // -// Specifically, this: -// * Merges global variables between the two modules -// * Uninit + Uninit = Init, Init + Uninit = Init, Init + Init = Error if != -// * Merges functions between two modules -// //===----------------------------------------------------------------------===// #include "llvm/Linker.h" #include "llvm/Constants.h" #include "llvm/DerivedTypes.h" -#include "llvm/LLVMContext.h" #include "llvm/Module.h" -#include "llvm/TypeSymbolTable.h" -#include "llvm/ValueSymbolTable.h" -#include "llvm/Instructions.h" -#include "llvm/Assembly/Writer.h" -#include "llvm/Support/Debug.h" -#include "llvm/Support/ErrorHandling.h" #include "llvm/Support/raw_ostream.h" #include "llvm/Support/Path.h" #include "llvm/Transforms/Utils/ValueMapper.h" -#include "llvm/ADT/DenseMap.h" using namespace llvm; -// Error - Simple wrapper function to conditionally assign to E and return true. -// This just makes error return conditions a little bit simpler... -static inline bool Error(std::string *E, const Twine &Message) { - if (E) *E = Message.str(); - return true; -} - -// Function: ResolveTypes() -// -// Description: -// Attempt to link the two specified types together. -// -// Inputs: -// DestTy - The type to which we wish to resolve. -// SrcTy - The original type which we want to resolve. -// -// Outputs: -// DestST - The symbol table in which the new type should be placed. -// -// Return value: -// true - There is an error and the types cannot yet be linked. -// false - No errors. -// -static bool ResolveTypes(const Type *DestTy, const Type *SrcTy) { - if (DestTy == SrcTy) return false; // If already equal, noop - assert(DestTy && SrcTy && "Can't handle null types"); - - if (const OpaqueType *OT = dyn_cast<OpaqueType>(DestTy)) { - // Type _is_ in module, just opaque... - const_cast<OpaqueType*>(OT)->refineAbstractTypeTo(SrcTy); - } else if (const OpaqueType *OT = dyn_cast<OpaqueType>(SrcTy)) { - const_cast<OpaqueType*>(OT)->refineAbstractTypeTo(DestTy); - } else { - return true; // Cannot link types... not-equal and neither is opaque. - } - return false; -} +//===----------------------------------------------------------------------===// +// TypeMap implementation. +//===----------------------------------------------------------------------===// -/// LinkerTypeMap - This implements a map of types that is stable -/// even if types are resolved/refined to other types. This is not a general -/// purpose map, it is specific to the linker's use. namespace { -class LinkerTypeMap : public AbstractTypeUser { - typedef DenseMap<const Type*, PATypeHolder> TheMapTy; - TheMapTy TheMap; - - LinkerTypeMap(const LinkerTypeMap&); // DO NOT IMPLEMENT - void operator=(const LinkerTypeMap&); // DO NOT IMPLEMENT +class TypeMapTy : public ValueMapTypeRemapper { + /// MappedTypes - This is a mapping from a source type to a destination type + /// to use. + DenseMap<Type*, Type*> MappedTypes; + + /// SpeculativeTypes - When checking to see if two subgraphs are isomorphic, + /// we speculatively add types to MappedTypes, but keep track of them here in + /// case we need to roll back. + SmallVector<Type*, 16> SpeculativeTypes; + + /// DefinitionsToResolve - This is a list of non-opaque structs in the source + /// module that are mapped to an opaque struct in the destination module. + SmallVector<StructType*, 16> DefinitionsToResolve; public: - LinkerTypeMap() {} - ~LinkerTypeMap() { - for (DenseMap<const Type*, PATypeHolder>::iterator I = TheMap.begin(), - E = TheMap.end(); I != E; ++I) - I->first->removeAbstractTypeUser(this); - } - - /// lookup - Return the value for the specified type or null if it doesn't - /// exist. - const Type *lookup(const Type *Ty) const { - TheMapTy::const_iterator I = TheMap.find(Ty); - if (I != TheMap.end()) return I->second; - return 0; - } - - /// insert - This returns true if the pointer was new to the set, false if it - /// was already in the set. - bool insert(const Type *Src, const Type *Dst) { - if (!TheMap.insert(std::make_pair(Src, PATypeHolder(Dst))).second) - return false; // Already in map. - if (Src->isAbstract()) - Src->addAbstractTypeUser(this); - return true; - } - -protected: - /// refineAbstractType - The callback method invoked when an abstract type is - /// resolved to another type. An object must override this method to update - /// its internal state to reference NewType instead of OldType. - /// - virtual void refineAbstractType(const DerivedType *OldTy, - const Type *NewTy) { - TheMapTy::iterator I = TheMap.find(OldTy); - const Type *DstTy = I->second; - - TheMap.erase(I); - if (OldTy->isAbstract()) - OldTy->removeAbstractTypeUser(this); - - // Don't reinsert into the map if the key is concrete now. - if (NewTy->isAbstract()) - insert(NewTy, DstTy); + + /// addTypeMapping - Indicate that the specified type in the destination + /// module is conceptually equivalent to the specified type in the source + /// module. + void addTypeMapping(Type *DstTy, Type *SrcTy); + + /// linkDefinedTypeBodies - Produce a body for an opaque type in the dest + /// module from a type definition in the source module. + void linkDefinedTypeBodies(); + + /// get - Return the mapped type to use for the specified input type from the + /// source module. + Type *get(Type *SrcTy); + + FunctionType *get(FunctionType *T) {return cast<FunctionType>(get((Type*)T));} + +private: + Type *getImpl(Type *T); + /// remapType - Implement the ValueMapTypeRemapper interface. + Type *remapType(Type *SrcTy) { + return get(SrcTy); } + + bool areTypesIsomorphic(Type *DstTy, Type *SrcTy); +}; +} - /// The other case which AbstractTypeUsers must be aware of is when a type - /// makes the transition from being abstract (where it has clients on it's - /// AbstractTypeUsers list) to concrete (where it does not). This method - /// notifies ATU's when this occurs for a type. - virtual void typeBecameConcrete(const DerivedType *AbsTy) { - TheMap.erase(AbsTy); - AbsTy->removeAbstractTypeUser(this); +void TypeMapTy::addTypeMapping(Type *DstTy, Type *SrcTy) { + Type *&Entry = MappedTypes[SrcTy]; + if (Entry) return; + + if (DstTy == SrcTy) { + Entry = DstTy; + return; } - - // for debugging... - virtual void dump() const { - dbgs() << "AbstractTypeSet!\n"; + + // Check to see if these types are recursively isomorphic and establish a + // mapping between them if so. + if (!areTypesIsomorphic(DstTy, SrcTy)) { + // Oops, they aren't isomorphic. Just discard this request by rolling out + // any speculative mappings we've established. + for (unsigned i = 0, e = SpeculativeTypes.size(); i != e; ++i) + MappedTypes.erase(SpeculativeTypes[i]); } -}; + SpeculativeTypes.clear(); } - -// RecursiveResolveTypes - This is just like ResolveTypes, except that it -// recurses down into derived types, merging the used types if the parent types -// are compatible. -static bool RecursiveResolveTypesI(const Type *DstTy, const Type *SrcTy, - LinkerTypeMap &Pointers) { - if (DstTy == SrcTy) return false; // If already equal, noop - - // If we found our opaque type, resolve it now! - if (DstTy->isOpaqueTy() || SrcTy->isOpaqueTy()) - return ResolveTypes(DstTy, SrcTy); - - // Two types cannot be resolved together if they are of different primitive - // type. For example, we cannot resolve an int to a float. - if (DstTy->getTypeID() != SrcTy->getTypeID()) return true; - - // If neither type is abstract, then they really are just different types. - if (!DstTy->isAbstract() && !SrcTy->isAbstract()) +/// areTypesIsomorphic - Recursively walk this pair of types, returning true +/// if they are isomorphic, false if they are not. +bool TypeMapTy::areTypesIsomorphic(Type *DstTy, Type *SrcTy) { + // Two types with differing kinds are clearly not isomorphic. + if (DstTy->getTypeID() != SrcTy->getTypeID()) return false; + + // If we have an entry in the MappedTypes table, then we have our answer. + Type *&Entry = MappedTypes[SrcTy]; + if (Entry) + return Entry == DstTy; + + // Two identical types are clearly isomorphic. Remember this + // non-speculatively. + if (DstTy == SrcTy) { + Entry = DstTy; return true; - - // Otherwise, resolve the used type used by this derived type... - switch (DstTy->getTypeID()) { - default: - return true; - case Type::FunctionTyID: { - const FunctionType *DstFT = cast<FunctionType>(DstTy); - const FunctionType *SrcFT = cast<FunctionType>(SrcTy); - if (DstFT->isVarArg() != SrcFT->isVarArg() || - DstFT->getNumContainedTypes() != SrcFT->getNumContainedTypes()) - return true; - - // Use TypeHolder's so recursive resolution won't break us. - PATypeHolder ST(SrcFT), DT(DstFT); - for (unsigned i = 0, e = DstFT->getNumContainedTypes(); i != e; ++i) { - const Type *SE = ST->getContainedType(i), *DE = DT->getContainedType(i); - if (SE != DE && RecursiveResolveTypesI(DE, SE, Pointers)) - return true; - } - return false; } - case Type::StructTyID: { - const StructType *DstST = cast<StructType>(DstTy); - const StructType *SrcST = cast<StructType>(SrcTy); - if (DstST->getNumContainedTypes() != SrcST->getNumContainedTypes()) + + // Okay, we have two types with identical kinds that we haven't seen before. + + // If this is an opaque struct type, special case it. + if (StructType *SSTy = dyn_cast<StructType>(SrcTy)) { + // Mapping an opaque type to any struct, just keep the dest struct. + if (SSTy->isOpaque()) { + Entry = DstTy; + SpeculativeTypes.push_back(SrcTy); return true; + } - PATypeHolder ST(SrcST), DT(DstST); - for (unsigned i = 0, e = DstST->getNumContainedTypes(); i != e; ++i) { - const Type *SE = ST->getContainedType(i), *DE = DT->getContainedType(i); - if (SE != DE && RecursiveResolveTypesI(DE, SE, Pointers)) - return true; + // Mapping a non-opaque source type to an opaque dest. Keep the dest, but + // fill it in later. This doesn't need to be speculative. + if (cast<StructType>(DstTy)->isOpaque()) { + Entry = DstTy; + DefinitionsToResolve.push_back(SSTy); + return true; } - return false; - } - case Type::ArrayTyID: { - const ArrayType *DAT = cast<ArrayType>(DstTy); - const ArrayType *SAT = cast<ArrayType>(SrcTy); - if (DAT->getNumElements() != SAT->getNumElements()) return true; - return RecursiveResolveTypesI(DAT->getElementType(), SAT->getElementType(), - Pointers); } - case Type::VectorTyID: { - const VectorType *DVT = cast<VectorType>(DstTy); - const VectorType *SVT = cast<VectorType>(SrcTy); - if (DVT->getNumElements() != SVT->getNumElements()) return true; - return RecursiveResolveTypesI(DVT->getElementType(), SVT->getElementType(), - Pointers); + + // If the number of subtypes disagree between the two types, then we fail. + if (SrcTy->getNumContainedTypes() != DstTy->getNumContainedTypes()) + return false; + + // Fail if any of the extra properties (e.g. array size) of the type disagree. + if (isa<IntegerType>(DstTy)) + return false; // bitwidth disagrees. + if (PointerType *PT = dyn_cast<PointerType>(DstTy)) { + if (PT->getAddressSpace() != cast<PointerType>(SrcTy)->getAddressSpace()) + return false; + } else if (FunctionType *FT = dyn_cast<FunctionType>(DstTy)) { + if (FT->isVarArg() != cast<FunctionType>(SrcTy)->isVarArg()) + return false; + } else if (StructType *DSTy = dyn_cast<StructType>(DstTy)) { + StructType *SSTy = cast<StructType>(SrcTy); + if (DSTy->isAnonymous() != SSTy->isAnonymous() || + DSTy->isPacked() != SSTy->isPacked()) + return false; + } else if (ArrayType *DATy = dyn_cast<ArrayType>(DstTy)) { + if (DATy->getNumElements() != cast<ArrayType>(SrcTy)->getNumElements()) + return false; + } else if (VectorType *DVTy = dyn_cast<VectorType>(DstTy)) { + if (DVTy->getNumElements() != cast<ArrayType>(SrcTy)->getNumElements()) + return false; } - case Type::PointerTyID: { - const PointerType *DstPT = cast<PointerType>(DstTy); - const PointerType *SrcPT = cast<PointerType>(SrcTy); - if (DstPT->getAddressSpace() != SrcPT->getAddressSpace()) - return true; + // Otherwise, we speculate that these two types will line up and recursively + // check the subelements. + Entry = DstTy; + SpeculativeTypes.push_back(SrcTy); + + for (unsigned i = 0, e = SrcTy->getNumContainedTypes(); i != e; ++i) + if (!areTypesIsomorphic(DstTy->getContainedType(i), + SrcTy->getContainedType(i))) + return false; + + // If everything seems to have lined up, then everything is great. + return true; +} - // If this is a pointer type, check to see if we have already seen it. If - // so, we are in a recursive branch. Cut off the search now. We cannot use - // an associative container for this search, because the type pointers (keys - // in the container) change whenever types get resolved. - if (SrcPT->isAbstract()) - if (const Type *ExistingDestTy = Pointers.lookup(SrcPT)) - return ExistingDestTy != DstPT; - - if (DstPT->isAbstract()) - if (const Type *ExistingSrcTy = Pointers.lookup(DstPT)) - return ExistingSrcTy != SrcPT; - // Otherwise, add the current pointers to the vector to stop recursion on - // this pair. - if (DstPT->isAbstract()) - Pointers.insert(DstPT, SrcPT); - if (SrcPT->isAbstract()) - Pointers.insert(SrcPT, DstPT); - - return RecursiveResolveTypesI(DstPT->getElementType(), - SrcPT->getElementType(), Pointers); - } +/// linkDefinedTypeBodies - Produce a body for an opaque type in the dest +/// module from a type definition in the source module. +void TypeMapTy::linkDefinedTypeBodies() { + SmallVector<Type*, 16> Elements; + SmallString<16> TmpName; + + // Note that processing entries in this loop (calling 'get') can add new + // entries to the DefinitionsToResolve vector. + while (!DefinitionsToResolve.empty()) { + StructType *SrcSTy = DefinitionsToResolve.pop_back_val(); + StructType *DstSTy = cast<StructType>(MappedTypes[SrcSTy]); + + // TypeMap is a many-to-one mapping, if there were multiple types that + // provide a body for DstSTy then previous iterations of this loop may have + // already handled it. Just ignore this case. + if (!DstSTy->isOpaque()) continue; + assert(!SrcSTy->isOpaque() && "Not resolving a definition?"); + + // Map the body of the source type over to a new body for the dest type. + Elements.resize(SrcSTy->getNumElements()); + for (unsigned i = 0, e = Elements.size(); i != e; ++i) + Elements[i] = getImpl(SrcSTy->getElementType(i)); + + DstSTy->setBody(Elements, SrcSTy->isPacked()); + + // If DstSTy has no name or has a longer name than STy, then viciously steal + // STy's name. + if (!SrcSTy->hasName()) continue; + StringRef SrcName = SrcSTy->getName(); + + if (!DstSTy->hasName() || DstSTy->getName().size() > SrcName.size()) { + TmpName.insert(TmpName.end(), SrcName.begin(), SrcName.end()); + SrcSTy->setName(""); + DstSTy->setName(TmpName.str()); + TmpName.clear(); + } } } -static bool RecursiveResolveTypes(const Type *DestTy, const Type *SrcTy) { - LinkerTypeMap PointerTypes; - return RecursiveResolveTypesI(DestTy, SrcTy, PointerTypes); -} +/// get - Return the mapped type to use for the specified input type from the +/// source module. +Type *TypeMapTy::get(Type *Ty) { + Type *Result = getImpl(Ty); + + // If this caused a reference to any struct type, resolve it before returning. + if (!DefinitionsToResolve.empty()) + linkDefinedTypeBodies(); + return Result; +} -// LinkTypes - Go through the symbol table of the Src module and see if any -// types are named in the src module that are not named in the Dst module. -// Make sure there are no type name conflicts. -static bool LinkTypes(Module *Dest, const Module *Src, std::string *Err) { - TypeSymbolTable *DestST = &Dest->getTypeSymbolTable(); - const TypeSymbolTable *SrcST = &Src->getTypeSymbolTable(); - - // Look for a type plane for Type's... - TypeSymbolTable::const_iterator TI = SrcST->begin(); - TypeSymbolTable::const_iterator TE = SrcST->end(); - if (TI == TE) return false; // No named types, do nothing. - - // Some types cannot be resolved immediately because they depend on other - // types being resolved to each other first. This contains a list of types we - // are waiting to recheck. - std::vector<std::string> DelayedTypesToResolve; - - for ( ; TI != TE; ++TI ) { - const std::string &Name = TI->first; - const Type *RHS = TI->second; - - // Check to see if this type name is already in the dest module. - Type *Entry = DestST->lookup(Name); - - // If the name is just in the source module, bring it over to the dest. - if (Entry == 0) { - if (!Name.empty()) - DestST->insert(Name, const_cast<Type*>(RHS)); - } else if (ResolveTypes(Entry, RHS)) { - // They look different, save the types 'till later to resolve. - DelayedTypesToResolve.push_back(Name); +/// getImpl - This is the recursive version of get(). +Type *TypeMapTy::getImpl(Type *Ty) { + // If we already have an entry for this type, return it. + Type **Entry = &MappedTypes[Ty]; + if (*Entry) return *Entry; + + // If this is not a named struct type, then just map all of the elements and + // then rebuild the type from inside out. + if (!isa<StructType>(Ty) || cast<StructType>(Ty)->isAnonymous()) { + // If there are no element types to map, then the type is itself. This is + // true for the anonymous {} struct, things like 'float', integers, etc. + if (Ty->getNumContainedTypes() == 0) + return *Entry = Ty; + + // Remap all of the elements, keeping track of whether any of them change. + bool AnyChange = false; + SmallVector<Type*, 4> ElementTypes; + ElementTypes.resize(Ty->getNumContainedTypes()); + for (unsigned i = 0, e = Ty->getNumContainedTypes(); i != e; ++i) { + ElementTypes[i] = getImpl(Ty->getContainedType(i)); + AnyChange |= ElementTypes[i] != Ty->getContainedType(i); + } + + // If we found our type while recursively processing stuff, just use it. + Entry = &MappedTypes[Ty]; + if (*Entry) return *Entry; + + // If all of the element types mapped directly over, then the type is usable + // as-is. + if (!AnyChange) + return *Entry = Ty; + + // Otherwise, rebuild a modified type. + switch (Ty->getTypeID()) { + default: assert(0 && "unknown derived type to remap"); + case Type::ArrayTyID: + return *Entry = ArrayType::get(ElementTypes[0], + cast<ArrayType>(Ty)->getNumElements()); + case Type::VectorTyID: + return *Entry = VectorType::get(ElementTypes[0], + cast<VectorType>(Ty)->getNumElements()); + case Type::PointerTyID: + return *Entry = PointerType::get(ElementTypes[0], + cast<PointerType>(Ty)->getAddressSpace()); + case Type::FunctionTyID: + return *Entry = FunctionType::get(ElementTypes[0], + ArrayRef<Type*>(ElementTypes).slice(1), + cast<FunctionType>(Ty)->isVarArg()); + case Type::StructTyID: + // Note that this is only reached for anonymous structs. + return *Entry = StructType::get(Ty->getContext(), ElementTypes, + cast<StructType>(Ty)->isPacked()); } } - // Iteratively resolve types while we can... - while (!DelayedTypesToResolve.empty()) { - // Loop over all of the types, attempting to resolve them if possible... - unsigned OldSize = DelayedTypesToResolve.size(); - - // Try direct resolution by name... - for (unsigned i = 0; i != DelayedTypesToResolve.size(); ++i) { - const std::string &Name = DelayedTypesToResolve[i]; - Type *T1 = SrcST->lookup(Name); - Type *T2 = DestST->lookup(Name); - if (!ResolveTypes(T2, T1)) { - // We are making progress! - DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i); - --i; - } - } + // Otherwise, this is an unmapped named struct. If the struct can be directly + // mapped over, just use it as-is. This happens in a case when the linked-in + // module has something like: + // %T = type {%T*, i32} + // @GV = global %T* null + // where T does not exist at all in the destination module. + // + // The other case we watch for is when the type is not in the destination + // module, but that it has to be rebuilt because it refers to something that + // is already mapped. For example, if the destination module has: + // %A = type { i32 } + // and the source module has something like + // %A' = type { i32 } + // %B = type { %A'* } + // @GV = global %B* null + // then we want to create a new type: "%B = type { %A*}" and have it take the + // pristine "%B" name from the source module. + // + // To determine which case this is, we have to recursively walk the type graph + // speculating that we'll be able to reuse it unmodified. Only if this is + // safe would we map the entire thing over. Because this is an optimization, + // and is not required for the prettiness of the linked module, we just skip + // it and always rebuild a type here. + StructType *STy = cast<StructType>(Ty); + + // If the type is opaque, we can just use it directly. + if (STy->isOpaque()) + return *Entry = STy; + + // Otherwise we create a new type and resolve its body later. This will be + // resolved by the top level of get(). + DefinitionsToResolve.push_back(STy); + return *Entry = StructType::createNamed(STy->getContext(), ""); +} - // Did we not eliminate any types? - if (DelayedTypesToResolve.size() == OldSize) { - // Attempt to resolve subelements of types. This allows us to merge these - // two types: { int* } and { opaque* } - for (unsigned i = 0, e = DelayedTypesToResolve.size(); i != e; ++i) { - const std::string &Name = DelayedTypesToResolve[i]; - if (!RecursiveResolveTypes(SrcST->lookup(Name), DestST->lookup(Name))) { - // We are making progress! - DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i); - - // Go back to the main loop, perhaps we can resolve directly by name - // now... - break; - } - } - // If we STILL cannot resolve the types, then there is something wrong. - if (DelayedTypesToResolve.size() == OldSize) { - // Remove the symbol name from the destination. - DelayedTypesToResolve.pop_back(); - } - } - } +//===----------------------------------------------------------------------===// +// ModuleLinker implementation. +//===----------------------------------------------------------------------===// - return false; +namespace { + /// ModuleLinker - This is an implementation class for the LinkModules + /// function, which is the entrypoint for this file. + class ModuleLinker { + Module *DstM, *SrcM; + + TypeMapTy TypeMap; + + /// ValueMap - Mapping of values from what they used to be in Src, to what + /// they are now in DstM. ValueToValueMapTy is a ValueMap, which involves + /// some overhead due to the use of Value handles which the Linker doesn't + /// actually need, but this allows us to reuse the ValueMapper code. + ValueToValueMapTy ValueMap; + + struct AppendingVarInfo { + GlobalVariable *NewGV; // New aggregate global in dest module. + Constant *DstInit; // Old initializer from dest module. + Constant *SrcInit; // Old initializer from src module. + }; + + std::vector<AppendingVarInfo> AppendingVars; + + public: + std::string ErrorMsg; + + ModuleLinker(Module *dstM, Module *srcM) : DstM(dstM), SrcM(srcM) { } + + bool run(); + + private: + /// emitError - Helper method for setting a message and returning an error + /// code. + bool emitError(const Twine &Message) { + ErrorMsg = Message.str(); + return true; + } + + /// getLinkageResult - This analyzes the two global values and determines + /// what the result will look like in the destination module. + bool getLinkageResult(GlobalValue *Dest, const GlobalValue *Src, + GlobalValue::LinkageTypes <, bool &LinkFromSrc); + + /// getLinkedToGlobal - Given a global in the source module, return the + /// global in the destination module that is being linked to, if any. + GlobalValue *getLinkedToGlobal(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()) + return 0; + + // Otherwise see if we have a match in the destination module's symtab. + GlobalValue *DGV = DstM->getNamedValue(SrcGV->getName()); + if (DGV == 0) return 0; + + // If we found a global with the same name in the dest module, but it has + // internal linkage, we are really not doing any linkage here. + if (DGV->hasLocalLinkage()) + return 0; + + // Otherwise, we do in fact link to the destination global. + return DGV; + } + + void computeTypeMapping(); + + bool linkAppendingVarProto(GlobalVariable *DstGV, GlobalVariable *SrcGV); + bool linkGlobalProto(GlobalVariable *SrcGV); + bool linkFunctionProto(Function *SrcF); + bool linkAliasProto(GlobalAlias *SrcA); + + void linkAppendingVarInit(const AppendingVarInfo &AVI); + void linkGlobalInits(); + void linkFunctionBody(Function *Dst, Function *Src); + void linkAliasBodies(); + void linkNamedMDNodes(); + }; } -/// ForceRenaming - The LLVM SymbolTable class autorenames globals that conflict + + +/// forceRenaming - The LLVM SymbolTable class autorenames globals that conflict /// in the symbol table. This is good for all clients except for us. Go /// through the trouble to force this back. -static void ForceRenaming(GlobalValue *GV, const std::string &Name) { - assert(GV->getName() != Name && "Can't force rename to self"); - ValueSymbolTable &ST = GV->getParent()->getValueSymbolTable(); +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. + if (GV->hasLocalLinkage() || GV->getName() == Name) + return; + + Module *M = GV->getParent(); // If there is a conflict, rename the conflict. - if (GlobalValue *ConflictGV = cast_or_null<GlobalValue>(ST.lookup(Name))) { - assert(ConflictGV->hasLocalLinkage() && - "Not conflicting with a static global, should link instead!"); + if (GlobalValue *ConflictGV = M->getNamedValue(Name)) { GV->takeName(ConflictGV); ConflictGV->setName(Name); // This will cause ConflictGV to get renamed - assert(ConflictGV->getName() != Name && "ForceRenaming didn't work"); + assert(ConflictGV->getName() != Name && "forceRenaming didn't work"); } else { GV->setName(Name); // Force the name back } @@ -352,30 +419,35 @@ static void CopyGVAttributes(GlobalValue *DestGV, const GlobalValue *SrcGV) { unsigned Alignment = std::max(DestGV->getAlignment(), SrcGV->getAlignment()); DestGV->copyAttributesFrom(SrcGV); DestGV->setAlignment(Alignment); + + forceRenaming(DestGV, SrcGV->getName()); } -/// GetLinkageResult - This analyzes the two global values and determines what +/// getLinkageResult - This analyzes the two global values and determines what /// the result will look like in the destination module. In particular, it /// computes the resultant linkage type, computes whether the global in the /// source should be copied over to the destination (replacing the existing /// one), and computes whether this linkage is an error or not. It also performs /// visibility checks: we cannot link together two symbols with different /// visibilities. -static bool GetLinkageResult(GlobalValue *Dest, const GlobalValue *Src, - GlobalValue::LinkageTypes <, bool &LinkFromSrc, - std::string *Err) { - assert((!Dest || !Src->hasLocalLinkage()) && +bool ModuleLinker::getLinkageResult(GlobalValue *Dest, const GlobalValue *Src, + GlobalValue::LinkageTypes <, + bool &LinkFromSrc) { + assert(Dest && "Must have two globals being queried"); + assert(!Src->hasLocalLinkage() && "If Src has internal linkage, Dest shouldn't be set!"); - if (!Dest) { - // Linking something to nothing. - LinkFromSrc = true; - LT = Src->getLinkage(); - } else if (Src->isDeclaration()) { + + // FIXME: GlobalAlias::isDeclaration is broken, should always be + // false. + bool SrcIsDeclaration = Src->isDeclaration() && !isa<GlobalAlias>(Src); + bool DestIsDeclaration = Dest->isDeclaration() && !isa<GlobalAlias>(Dest); + + if (SrcIsDeclaration) { // If Src is external or if both Src & Dest are external.. Just link the // external globals, we aren't adding anything. if (Src->hasDLLImportLinkage()) { // If one of GVs has DLLImport linkage, result should be dllimport'ed. - if (Dest->isDeclaration()) { + if (DestIsDeclaration) { LinkFromSrc = true; LT = Src->getLinkage(); } @@ -387,16 +459,10 @@ static bool GetLinkageResult(GlobalValue *Dest, const GlobalValue *Src, LinkFromSrc = false; LT = Dest->getLinkage(); } - } else if (Dest->isDeclaration() && !Dest->hasDLLImportLinkage()) { + } else if (DestIsDeclaration && !Dest->hasDLLImportLinkage()) { // If Dest is external but Src is not: LinkFromSrc = true; LT = Src->getLinkage(); - } else if (Src->hasAppendingLinkage() || Dest->hasAppendingLinkage()) { - if (Src->getLinkage() != Dest->getLinkage()) - return Error(Err, "Linking globals named '" + Src->getName() + - "': can only link appending global with another appending global!"); - LinkFromSrc = true; // Special cased. - LT = Src->getLinkage(); } else if (Src->isWeakForLinker()) { // At this point we know that Dest has LinkOnce, External*, Weak, Common, // or DLL* linkage. @@ -420,883 +486,485 @@ static bool GetLinkageResult(GlobalValue *Dest, const GlobalValue *Src, LT = GlobalValue::ExternalLinkage; } } else { - assert((Dest->hasExternalLinkage() || - Dest->hasDLLImportLinkage() || - Dest->hasDLLExportLinkage() || - Dest->hasExternalWeakLinkage()) && - (Src->hasExternalLinkage() || - Src->hasDLLImportLinkage() || - Src->hasDLLExportLinkage() || - Src->hasExternalWeakLinkage()) && + assert((Dest->hasExternalLinkage() || Dest->hasDLLImportLinkage() || + Dest->hasDLLExportLinkage() || Dest->hasExternalWeakLinkage()) && + (Src->hasExternalLinkage() || Src->hasDLLImportLinkage() || + Src->hasDLLExportLinkage() || Src->hasExternalWeakLinkage()) && "Unexpected linkage type!"); - return Error(Err, "Linking globals named '" + Src->getName() + + return emitError("Linking globals named '" + Src->getName() + "': symbol multiply defined!"); } // Check visibility - if (Dest && Src->getVisibility() != Dest->getVisibility() && - !Src->isDeclaration() && !Dest->isDeclaration() && + if (Src->getVisibility() != Dest->getVisibility() && + !SrcIsDeclaration && !DestIsDeclaration && !Src->hasAvailableExternallyLinkage() && !Dest->hasAvailableExternallyLinkage()) - return Error(Err, "Linking globals named '" + Src->getName() + + return emitError("Linking globals named '" + Src->getName() + "': symbols have different visibilities!"); return false; } -// Insert all of the named mdnoes in Src into the Dest module. -static void LinkNamedMDNodes(Module *Dest, Module *Src, - ValueToValueMapTy &ValueMap) { - for (Module::const_named_metadata_iterator I = Src->named_metadata_begin(), - E = Src->named_metadata_end(); I != E; ++I) { - const NamedMDNode *SrcNMD = I; - NamedMDNode *DestNMD = Dest->getOrInsertNamedMetadata(SrcNMD->getName()); - // Add Src elements into Dest node. - for (unsigned i = 0, e = SrcNMD->getNumOperands(); i != e; ++i) - DestNMD->addOperand(cast<MDNode>(MapValue(SrcNMD->getOperand(i), - ValueMap))); +/// computeTypeMapping - Loop over all of the linked values to compute type +/// mappings. For example, if we link "extern Foo *x" and "Foo *x = NULL", then +/// we have two struct types 'Foo' but one got renamed when the module was +/// loaded into the same LLVMContext. +void ModuleLinker::computeTypeMapping() { + // Incorporate globals. + for (Module::global_iterator I = SrcM->global_begin(), + E = SrcM->global_end(); I != E; ++I) { + GlobalValue *DGV = getLinkedToGlobal(I); + if (DGV == 0) continue; + + if (!DGV->hasAppendingLinkage() || !I->hasAppendingLinkage()) { + TypeMap.addTypeMapping(DGV->getType(), I->getType()); + continue; + } + + // Unify the element type of appending arrays. + ArrayType *DAT = cast<ArrayType>(DGV->getType()->getElementType()); + ArrayType *SAT = cast<ArrayType>(I->getType()->getElementType()); + TypeMap.addTypeMapping(DAT->getElementType(), SAT->getElementType()); } + + // Incorporate functions. + for (Module::iterator I = SrcM->begin(), E = SrcM->end(); I != E; ++I) { + if (GlobalValue *DGV = getLinkedToGlobal(I)) + TypeMap.addTypeMapping(DGV->getType(), I->getType()); + } + + // Don't bother incorporating aliases, they aren't generally typed well. + + // Now that we have discovered all of the type equivalences, get a body for + // any 'opaque' types in the dest module that are now resolved. + TypeMap.linkDefinedTypeBodies(); } -// LinkGlobals - Loop through the global variables in the src module and merge -// them into the dest module. -static bool LinkGlobals(Module *Dest, const Module *Src, - ValueToValueMapTy &ValueMap, - std::multimap<std::string, GlobalVariable *> &AppendingVars, - std::string *Err) { - ValueSymbolTable &DestSymTab = Dest->getValueSymbolTable(); - - // Loop over all of the globals in the src module, mapping them over as we go - for (Module::const_global_iterator I = Src->global_begin(), - E = Src->global_end(); I != E; ++I) { - const GlobalVariable *SGV = I; - GlobalValue *DGV = 0; - - // Check to see if may have to link the global with the global, alias or - // function. - if (SGV->hasName() && !SGV->hasLocalLinkage()) - DGV = cast_or_null<GlobalValue>(DestSymTab.lookup(SGV->getName())); - - // If we found a global with the same name in the dest module, but it has - // internal linkage, we are really not doing any linkage here. - if (DGV && DGV->hasLocalLinkage()) - DGV = 0; - - // If types don't agree due to opaque types, try to resolve them. - if (DGV && DGV->getType() != SGV->getType()) - RecursiveResolveTypes(SGV->getType(), DGV->getType()); - - assert((SGV->hasInitializer() || SGV->hasExternalWeakLinkage() || - SGV->hasExternalLinkage() || SGV->hasDLLImportLinkage()) && - "Global must either be external or have an initializer!"); +/// linkAppendingVarProto - If there were any appending global variables, link +/// them together now. Return true on error. +bool ModuleLinker::linkAppendingVarProto(GlobalVariable *DstGV, + GlobalVariable *SrcGV) { + + if (!SrcGV->hasAppendingLinkage() || !DstGV->hasAppendingLinkage()) + return emitError("Linking globals named '" + SrcGV->getName() + + "': can only link appending global with another appending global!"); + + ArrayType *DstTy = cast<ArrayType>(DstGV->getType()->getElementType()); + ArrayType *SrcTy = + cast<ArrayType>(TypeMap.get(SrcGV->getType()->getElementType())); |