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Diffstat (limited to 'contrib/llvm/lib/Linker/LinkModules.cpp')
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diff --git a/contrib/llvm/lib/Linker/LinkModules.cpp b/contrib/llvm/lib/Linker/LinkModules.cpp new file mode 100644 index 0000000..03a962e --- /dev/null +++ b/contrib/llvm/lib/Linker/LinkModules.cpp @@ -0,0 +1,1002 @@ +//===- lib/Linker/LinkModules.cpp - Module Linker Implementation ----------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file implements the LLVM module linker. +// +//===----------------------------------------------------------------------===// + +#include "llvm/Linker.h" +#include "llvm/Constants.h" +#include "llvm/DerivedTypes.h" +#include "llvm/Instructions.h" +#include "llvm/Module.h" +#include "llvm/ADT/SmallPtrSet.h" +#include "llvm/Support/raw_ostream.h" +#include "llvm/Support/Path.h" +#include "llvm/Transforms/Utils/Cloning.h" +#include "llvm/Transforms/Utils/ValueMapper.h" +using namespace llvm; + +//===----------------------------------------------------------------------===// +// TypeMap implementation. +//===----------------------------------------------------------------------===// + +namespace { +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: + + /// 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); +}; +} + +void TypeMapTy::addTypeMapping(Type *DstTy, Type *SrcTy) { + Type *&Entry = MappedTypes[SrcTy]; + if (Entry) return; + + if (DstTy == SrcTy) { + Entry = DstTy; + return; + } + + // 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(); +} + +/// 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; + } + + // 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; + } + + // 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; + } + } + + // 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->isLiteral() != SSTy->isLiteral() || + 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; + } + + // 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; +} + +/// 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(); + } + } +} + + +/// 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; +} + +/// 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)->isLiteral()) { + // 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], + makeArrayRef(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()); + } + } + + // 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::create(STy->getContext()); +} + + + +//===----------------------------------------------------------------------===// +// ModuleLinker implementation. +//===----------------------------------------------------------------------===// + +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; + + unsigned Mode; // Mode to treat source module. + + // Set of items not to link in from source. + SmallPtrSet<const Value*, 16> DoNotLinkFromSource; + + public: + std::string ErrorMsg; + + ModuleLinker(Module *dstM, Module *srcM, unsigned mode) + : DstM(dstM), SrcM(srcM), Mode(mode) { } + + 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 +/// 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, 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 = M->getNamedValue(Name)) { + GV->takeName(ConflictGV); + ConflictGV->setName(Name); // This will cause ConflictGV to get renamed + assert(ConflictGV->getName() != Name && "forceRenaming didn't work"); + } else { + GV->setName(Name); // Force the name back + } +} + +/// CopyGVAttributes - copy additional attributes (those not needed to construct +/// a GlobalValue) from the SrcGV to the DestGV. +static void CopyGVAttributes(GlobalValue *DestGV, const GlobalValue *SrcGV) { + // Use the maximum alignment, rather than just copying the alignment of 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 +/// 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. +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!"); + + bool SrcIsDeclaration = Src->isDeclaration(); + bool DestIsDeclaration = Dest->isDeclaration(); + + 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 (DestIsDeclaration) { + LinkFromSrc = true; + LT = Src->getLinkage(); + } + } else if (Dest->hasExternalWeakLinkage()) { + // If the Dest is weak, use the source linkage. + LinkFromSrc = true; + LT = Src->getLinkage(); + } else { + LinkFromSrc = false; + LT = Dest->getLinkage(); + } + } else if (DestIsDeclaration && !Dest->hasDLLImportLinkage()) { + // If Dest is external but Src is not: + LinkFromSrc = true; + LT = Src->getLinkage(); + } else if (Src->isWeakForLinker()) { + // At this point we know that Dest has LinkOnce, External*, Weak, Common, + // or DLL* linkage. + if (Dest->hasExternalWeakLinkage() || + Dest->hasAvailableExternallyLinkage() || + (Dest->hasLinkOnceLinkage() && + (Src->hasWeakLinkage() || Src->hasCommonLinkage()))) { + LinkFromSrc = true; + LT = Src->getLinkage(); + } else { + LinkFromSrc = false; + LT = Dest->getLinkage(); + } + } else if (Dest->isWeakForLinker()) { + // At this point we know that Src has External* or DLL* linkage. + if (Src->hasExternalWeakLinkage()) { + LinkFromSrc = false; + LT = Dest->getLinkage(); + } else { + LinkFromSrc = true; + LT = GlobalValue::ExternalLinkage; + } + } else { + assert((Dest->hasExternalLinkage() || Dest->hasDLLImportLinkage() || + Dest->hasDLLExportLinkage() || Dest->hasExternalWeakLinkage()) && + (Src->hasExternalLinkage() || Src->hasDLLImportLinkage() || + Src->hasDLLExportLinkage() || Src->hasExternalWeakLinkage()) && + "Unexpected linkage type!"); + return emitError("Linking globals named '" + Src->getName() + + "': symbol multiply defined!"); + } + + // Check visibility + if (Src->getVisibility() != Dest->getVisibility() && + !SrcIsDeclaration && !DestIsDeclaration && + !Src->hasAvailableExternallyLinkage() && + !Dest->hasAvailableExternallyLinkage()) + return emitError("Linking globals named '" + Src->getName() + + "': symbols have different visibilities!"); + return false; +} + +/// 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(); +} + +/// 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())); + Type *EltTy = DstTy->getElementType(); + + // 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!"); + + 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->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*/0, /*name*/"", DstGV, + DstGV->isThreadLocal(), + DstGV->getType()->getAddressSpace()); + + // Propagate alignment, visibility and section info. + CopyGVAttributes(NG, DstGV); + + AppendingVarInfo AVI; + AVI.NewGV = NG; + AVI.DstInit = DstGV->getInitializer(); + AVI.SrcInit = SrcGV->getInitializer(); + AppendingVars.push_back(AVI); + + // Replace any uses of the two global variables with uses of the new + // global. + ValueMap[SrcGV] = ConstantExpr::getBitCast(NG, TypeMap.get(SrcGV->getType())); + + DstGV->replaceAllUsesWith(ConstantExpr::getBitCast(NG, DstGV->getType())); + DstGV->eraseFromParent(); + + // Track the source variable so we don't try to link it. + DoNotLinkFromSource.insert(SrcGV); + + return false; +} + +/// linkGlobalProto - Loop through the global variables in the src module and +/// merge them into the dest module. +bool ModuleLinker::linkGlobalProto(GlobalVariable *SGV) { + GlobalValue *DGV = getLinkedToGlobal(SGV); + + if (DGV) { + // Concatenation of appending linkage variables is magic and handled later. + if (DGV->hasAppendingLinkage() || SGV->hasAppendingLinkage()) + return linkAppendingVarProto(cast<GlobalVariable>(DGV), SGV); + + // Determine whether linkage of these two globals follows the source + // module's definition or the destination module's definition. + GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; + bool LinkFromSrc = false; + if (getLinkageResult(DGV, SGV, NewLinkage, LinkFromSrc)) + return true; + + // If we're not linking from the source, then keep the definition that we + // have. + if (!LinkFromSrc) { + // Special case for const propagation. + if (GlobalVariable *DGVar = dyn_cast<GlobalVariable>(DGV)) + if (DGVar->isDeclaration() && SGV->isConstant() && !DGVar->isConstant()) + DGVar->setConstant(true); + + // Set calculated linkage. + DGV->setLinkage(NewLinkage); + + // Make sure to remember this mapping. + ValueMap[SGV] = ConstantExpr::getBitCast(DGV,TypeMap.get(SGV->getType())); + + // Track the source global so that we don't attempt to copy it over when + // processing global initializers. + DoNotLinkFromSource.insert(SGV); + + return false; + } + } + + // 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(SGV->getType()->getElementType()), + SGV->isConstant(), SGV->getLinkage(), /*init*/0, + SGV->getName(), /*insertbefore*/0, + SGV->isThreadLocal(), + SGV->getType()->getAddressSpace()); + // Propagate alignment, visibility and section info. + CopyGVAttributes(NewDGV, SGV); + + if (DGV) { + DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDGV, DGV->getType())); + DGV->eraseFromParent(); + } + + // Make sure to remember this mapping. + ValueMap[SGV] = NewDGV; + return false; +} + +/// linkFunctionProto - Link the function in the source module into the +/// destination module if needed, setting up mapping information. +bool ModuleLinker::linkFunctionProto(Function *SF) { + GlobalValue *DGV = getLinkedToGlobal(SF); + + if (DGV) { + GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; + bool LinkFromSrc = false; + if (getLinkageResult(DGV, SF, NewLinkage, LinkFromSrc)) + return true; + + if (!LinkFromSrc) { + // Set calculated linkage + DGV->setLinkage(NewLinkage); + + // Make sure to remember this mapping. + ValueMap[SF] = ConstantExpr::getBitCast(DGV, TypeMap.get(SF->getType())); + + // Track the function from the source module so we don't attempt to remap + // it. + DoNotLinkFromSource.insert(SF); + + return false; + } + } + + // If there is no linkage to be performed or we are linking from the source, + // bring SF over. + Function *NewDF = Function::Create(TypeMap.get(SF->getFunctionType()), + SF->getLinkage(), SF->getName(), DstM); + CopyGVAttributes(NewDF, SF); + + if (DGV) { + // Any uses of DF need to change to NewDF, with cast. + DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDF, DGV->getType())); + DGV->eraseFromParent(); + } + + ValueMap[SF] = NewDF; + return false; +} + +/// LinkAliasProto - Set up prototypes for any aliases that come over from the +/// source module. +bool ModuleLinker::linkAliasProto(GlobalAlias *SGA) { + GlobalValue *DGV = getLinkedToGlobal(SGA); + + if (DGV) { + GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; + bool LinkFromSrc = false; + if (getLinkageResult(DGV, SGA, NewLinkage, LinkFromSrc)) + return true; + + if (!LinkFromSrc) { + // Set calculated linkage. + DGV->setLinkage(NewLinkage); + + // Make sure to remember this mapping. + ValueMap[SGA] = ConstantExpr::getBitCast(DGV,TypeMap.get(SGA->getType())); + + // Track the alias from the source module so we don't attempt to remap it. + DoNotLinkFromSource.insert(SGA); + + return false; + } + } + + // If there is no linkage to be performed or we're linking from the source, + // bring over SGA. + GlobalAlias *NewDA = new GlobalAlias(TypeMap.get(SGA->getType()), + SGA->getLinkage(), SGA->getName(), + /*aliasee*/0, DstM); + CopyGVAttributes(NewDA, SGA); + + if (DGV) { + // Any uses of DGV need to change to NewDA, with cast. + DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDA, DGV->getType())); + DGV->eraseFromParent(); + } + + ValueMap[SGA] = NewDA; + return false; +} + +void ModuleLinker::linkAppendingVarInit(const AppendingVarInfo &AVI) { + // Merge the initializer. + SmallVector<Constant*, 16> Elements; + if (ConstantArray *I = dyn_cast<ConstantArray>(AVI.DstInit)) { + for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) + Elements.push_back(I->getOperand(i)); + } else { + assert(isa<ConstantAggregateZero>(AVI.DstInit)); + ArrayType *DstAT = cast<ArrayType>(AVI.DstInit->getType()); + Type *EltTy = DstAT->getElementType(); + Elements.append(DstAT->getNumElements(), Constant::getNullValue(EltTy)); + } + + Constant *SrcInit = MapValue(AVI.SrcInit, ValueMap, RF_None, &TypeMap); + if (const ConstantArray *I = dyn_cast<ConstantArray>(SrcInit)) { + for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) + Elements.push_back(I->getOperand(i)); + } else { + assert(isa<ConstantAggregateZero>(SrcInit)); + ArrayType *SrcAT = cast<ArrayType>(SrcInit->getType()); + Type *EltTy = SrcAT->getElementType(); + Elements.append(SrcAT->getNumElements(), Constant::getNullValue(EltTy)); + } + ArrayType *NewType = cast<ArrayType>(AVI.NewGV->getType()->getElementType()); + AVI.NewGV->setInitializer(ConstantArray::get(NewType, Elements)); +} + + +// linkGlobalInits - 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<GlobalVariable>(ValueMap[I]); + // Figure out what the initializer looks like in the dest module. + DGV->setInitializer(MapValue(I->getInitializer(), ValueMap, + RF_None, &TypeMap)); + } +} + +// linkFunctionBody - 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()); + + // 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. + + // Add a mapping to our mapping. + ValueMap[I] = DI; + } + + if (Mode == Linker::DestroySource) { + // Splice the body of the source function into the dest function. + 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); + + } else { + // Clone the body of the function into the dest function. + SmallVector<ReturnInst*, 8> Returns; // Ignore returns. + CloneFunctionInto(Dst, Src, ValueMap, false, Returns); + } + + // 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); + +} + + +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<GlobalAlias>(ValueMap[I]); + DA->setAliasee(MapValue(Aliasee, ValueMap, RF_None, &TypeMap)); + } + } +} + +/// linkNamedMDNodes - Insert all of the named mdnodes in Src into the Dest +/// module. +void ModuleLinker::linkNamedMDNodes() { + for (Module::const_named_metadata_iterator I = SrcM->named_metadata_begin(), + E = SrcM->named_metadata_end(); I != E; ++I) { + NamedMDNode *DestNMD = DstM->getOrInsertNamedMetadata(I->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)); + } +} + +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().empty() && !SrcM->getDataLayout().empty()) + 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().empty() && !DstM->getDataLayout().empty() && + SrcM->getDataLayout() != DstM->getDataLayout()) + errs() << "WARNING: Linking two modules of different data layouts!\n"; + if (!SrcM->getTargetTriple().empty() && + DstM->getTargetTriple() != SrcM->getTargetTriple()) { + errs() << "WARNING: Linking two modules of different target triples: "; + if (!SrcM->getModuleIdentifier().empty()) + errs() << SrcM->getModuleIdentifier() << ": "; + errs() << "'" << SrcM->getTargetTriple() << "' and '" + << DstM->getTargetTriple() << "'\n"; + } + + // Append the module inline asm string. + if (!SrcM->getModuleInlineAsm().empty()) { + if (DstM->getModuleInlineAsm().empty()) + DstM->setModuleInlineAsm(SrcM->getModuleInlineAsm()); + else + DstM->setModuleInlineAsm(DstM->getModuleInlineAsm()+"\n"+ + SrcM->getModuleInlineAsm()); + } + + // Update the destination module's dependent libraries list with the libraries + // from the source module. There's no opportunity for duplicates here as the + // Module ensures that duplicate insertions are discarded. + for (Module::lib_iterator SI = SrcM->lib_begin(), SE = SrcM->lib_end(); + SI != SE; ++SI) + DstM->addLibrary(*SI); + + // If the source library's module id is in the dependent library list of the + // destination library, remove it since that module is now linked in. + StringRef ModuleId = SrcM->getModuleIdentifier(); + if (!ModuleId.empty()) + DstM->removeLibrary(sys::path::stem(ModuleId)); + + // Loop over all of the linked values to compute type mappings. + computeTypeMapping(); + + // 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 (linkGlobalProto(I)) + 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 (linkFunctionProto(I)) + 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 (linkAliasProto(I)) + return true; + + for (unsigned i = 0, e = AppendingVars.size(); i != e; ++i) + linkAppendingVarInit(AppendingVars[i]); + + // Update the initializers in the DstM module now that all globals that may + // be referenced are in DstM. + linkGlobalInits(); + + // 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; + + // Skip if no body (function is external) or materialize. + if (SF->isDeclaration()) { + if (!SF->isMaterializable()) + continue; + if (SF->Materialize(&ErrorMsg)) + return true; + } + + linkFunctionBody(cast<Function>(ValueMap[SF]), SF); + } + + // Resolve all uses of aliases with aliasees. + linkAliasBodies(); + + // Remap all of the named mdnoes in Src into the DstM module. We do this + // after linking GlobalValues so that MDNodes that reference GlobalValues + // are properly remapped. + linkNamedMDNodes(); + + // Now that all of the types from the source are used, resolve any structs + // copied over to the dest that didn't exist there. + TypeMap.linkDefinedTypeBodies(); + + return false; +} + +//===----------------------------------------------------------------------===// +// LinkModules entrypoint. +//===----------------------------------------------------------------------===// + +// LinkModules - This function links two modules together, with the resulting +// left module modified to be the composite of the two input modules. If an +// error occurs, true is returned and ErrorMsg (if not null) is set to indicate +// the problem. 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, unsigned Mode, + std::string *ErrorMsg) { + ModuleLinker TheLinker(Dest, Src, Mode); + if (TheLinker.run()) { + if (ErrorMsg) *ErrorMsg = TheLinker.ErrorMsg; + return true; + } + + return false; +} |
