diff options
Diffstat (limited to 'contrib/llvm/lib/Linker/LinkModules.cpp')
| -rw-r--r-- | contrib/llvm/lib/Linker/LinkModules.cpp | 1383 |
1 files changed, 1383 insertions, 0 deletions
diff --git a/contrib/llvm/lib/Linker/LinkModules.cpp b/contrib/llvm/lib/Linker/LinkModules.cpp new file mode 100644 index 0000000..8487c83 --- /dev/null +++ b/contrib/llvm/lib/Linker/LinkModules.cpp @@ -0,0 +1,1383 @@ +//===- 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. +// +// 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/System/Path.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; +} + +/// 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 +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; + } + + /// erase - Remove the specified type, returning true if it was in the set. + bool erase(const Type *Ty) { + if (!TheMap.erase(Ty)) + return false; + if (Ty->isAbstract()) + Ty->removeAbstractTypeUser(this); + return true; + } + + /// 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); + } + + /// 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); + } + + // for debugging... + virtual void dump() const { + dbgs() << "AbstractTypeSet!\n"; + } +}; +} + + +// 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()) + 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()) + 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; + } + 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); + } + case Type::PointerTyID: { + const PointerType *DstPT = cast<PointerType>(DstTy); + const PointerType *SrcPT = cast<PointerType>(SrcTy); + + if (DstPT->getAddressSpace() != SrcPT->getAddressSpace()) + 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); + } + } +} + +static bool RecursiveResolveTypes(const Type *DestTy, const Type *SrcTy) { + LinkerTypeMap PointerTypes; + return RecursiveResolveTypesI(DestTy, SrcTy, PointerTypes); +} + + +// 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); + } + } + + // 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; + } + } + + // 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(); + } + } + } + + + return false; +} + +#ifndef NDEBUG +static void PrintMap(const std::map<const Value*, Value*> &M) { + for (std::map<const Value*, Value*>::const_iterator I = M.begin(), E =M.end(); + I != E; ++I) { + dbgs() << " Fr: " << (void*)I->first << " "; + I->first->dump(); + dbgs() << " To: " << (void*)I->second << " "; + I->second->dump(); + dbgs() << "\n"; + } +} +#endif + + +// RemapOperand - Use ValueMap to convert constants from one module to another. +static Value *RemapOperand(const Value *In, + std::map<const Value*, Value*> &ValueMap) { + std::map<const Value*,Value*>::const_iterator I = ValueMap.find(In); + if (I != ValueMap.end()) + return I->second; + + // Check to see if it's a constant that we are interested in transforming. + Value *Result = 0; + if (const Constant *CPV = dyn_cast<Constant>(In)) { + if ((!isa<DerivedType>(CPV->getType()) && !isa<ConstantExpr>(CPV)) || + isa<ConstantInt>(CPV) || isa<ConstantAggregateZero>(CPV)) + return const_cast<Constant*>(CPV); // Simple constants stay identical. + + if (const ConstantArray *CPA = dyn_cast<ConstantArray>(CPV)) { + std::vector<Constant*> Operands(CPA->getNumOperands()); + for (unsigned i = 0, e = CPA->getNumOperands(); i != e; ++i) + Operands[i] =cast<Constant>(RemapOperand(CPA->getOperand(i), ValueMap)); + Result = ConstantArray::get(cast<ArrayType>(CPA->getType()), Operands); + } else if (const ConstantStruct *CPS = dyn_cast<ConstantStruct>(CPV)) { + std::vector<Constant*> Operands(CPS->getNumOperands()); + for (unsigned i = 0, e = CPS->getNumOperands(); i != e; ++i) + Operands[i] =cast<Constant>(RemapOperand(CPS->getOperand(i), ValueMap)); + Result = ConstantStruct::get(cast<StructType>(CPS->getType()), Operands); + } else if (isa<ConstantPointerNull>(CPV) || isa<UndefValue>(CPV)) { + Result = const_cast<Constant*>(CPV); + } else if (const ConstantVector *CP = dyn_cast<ConstantVector>(CPV)) { + std::vector<Constant*> Operands(CP->getNumOperands()); + for (unsigned i = 0, e = CP->getNumOperands(); i != e; ++i) + Operands[i] = cast<Constant>(RemapOperand(CP->getOperand(i), ValueMap)); + Result = ConstantVector::get(Operands); + } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CPV)) { + std::vector<Constant*> Ops; + for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) + Ops.push_back(cast<Constant>(RemapOperand(CE->getOperand(i),ValueMap))); + Result = CE->getWithOperands(Ops); + } else if (const BlockAddress *CE = dyn_cast<BlockAddress>(CPV)) { + Result = BlockAddress::get( + cast<Function>(RemapOperand(CE->getFunction(), ValueMap)), + CE->getBasicBlock()); + } else { + assert(!isa<GlobalValue>(CPV) && "Unmapped global?"); + llvm_unreachable("Unknown type of derived type constant value!"); + } + } else if (const MDNode *MD = dyn_cast<MDNode>(In)) { + if (MD->isFunctionLocal()) { + SmallVector<Value*, 4> Elts; + for (unsigned i = 0, e = MD->getNumOperands(); i != e; ++i) { + if (MD->getOperand(i)) + Elts.push_back(RemapOperand(MD->getOperand(i), ValueMap)); + else + Elts.push_back(NULL); + } + Result = MDNode::get(In->getContext(), Elts.data(), MD->getNumOperands()); + } else { + Result = const_cast<Value*>(In); + } + } else if (isa<MDString>(In) || isa<InlineAsm>(In) || isa<Instruction>(In)) { + Result = const_cast<Value*>(In); + } + + // Cache the mapping in our local map structure + if (Result) { + ValueMap[In] = Result; + return Result; + } + +#ifndef NDEBUG + dbgs() << "LinkModules ValueMap: \n"; + PrintMap(ValueMap); + + dbgs() << "Couldn't remap value: " << (void*)In << " " << *In << "\n"; + llvm_unreachable("Couldn't remap value!"); +#endif + return 0; +} + +/// 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(); + + // 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!"); + 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); +} + +/// 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()) && + "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()) { + // 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()) { + 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 (Dest->isDeclaration() && !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. + 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 Error(Err, "Linking globals named '" + Src->getName() + + "': symbol multiply defined!"); + } + + // Check visibility + if (Dest && Src->getVisibility() != Dest->getVisibility()) + if (!Src->isDeclaration() && !Dest->isDeclaration()) + return Error(Err, "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) { + 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->getNamedMetadata(SrcNMD->getName()); + if (!DestNMD) + NamedMDNode::Create(SrcNMD, Dest); + else { + // Add Src elements into Dest node. + for (unsigned i = 0, e = SrcNMD->getNumOperands(); i != e; ++i) + DestNMD->addOperand(SrcNMD->getOperand(i)); + } + } +} + +// 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, + std::map<const Value*, Value*> &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!"); + + GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; + bool LinkFromSrc = false; + if (GetLinkageResult(DGV, SGV, NewLinkage, LinkFromSrc, Err)) + return true; + + if (DGV == 0) { + // No linking to be performed, 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(*Dest, SGV->getType()->getElementType(), + SGV->isConstant(), SGV->getLinkage(), /*init*/0, + SGV->getName(), 0, false, + SGV->getType()->getAddressSpace()); + // Propagate alignment, visibility and section info. + CopyGVAttributes(NewDGV, SGV); + + // If the LLVM runtime renamed the global, but it is an externally visible + // symbol, DGV must be an existing global with internal linkage. Rename + // it. + if (!NewDGV->hasLocalLinkage() && NewDGV->getName() != SGV->getName()) + ForceRenaming(NewDGV, SGV->getName()); + + // Make sure to remember this mapping. + ValueMap[SGV] = NewDGV; + + // Keep track that this is an appending variable. + if (SGV->hasAppendingLinkage()) + AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV)); + continue; + } + + // If the visibilities of the symbols disagree and the destination is a + // prototype, take the visibility of its input. + if (DGV->isDeclaration()) + DGV->setVisibility(SGV->getVisibility()); + + if (DGV->hasAppendingLinkage()) { + // No linking is performed yet. Just insert a new copy of the global, and + // keep track of the fact that it is an appending variable in the + // AppendingVars map. The name is cleared out so that no linkage is + // performed. + GlobalVariable *NewDGV = + new GlobalVariable(*Dest, SGV->getType()->getElementType(), + SGV->isConstant(), SGV->getLinkage(), /*init*/0, + "", 0, false, + SGV->getType()->getAddressSpace()); + + // Set alignment allowing CopyGVAttributes merge it with alignment of SGV. + NewDGV->setAlignment(DGV->getAlignment()); + // Propagate alignment, section and visibility info. + CopyGVAttributes(NewDGV, SGV); + + // Make sure to remember this mapping... + ValueMap[SGV] = NewDGV; + + // Keep track that this is an appending variable... + AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV)); + continue; + } + + if (LinkFromSrc) { + if (isa<GlobalAlias>(DGV)) + return Error(Err, "Global-Alias Collision on '" + SGV->getName() + + "': symbol multiple defined"); + + // If the types don't match, and if we are to link from the source, nuke + // DGV and create a new one of the appropriate type. Note that the thing + // we are replacing may be a function (if a prototype, weak, etc) or a + // global variable. + GlobalVariable *NewDGV = + new GlobalVariable(*Dest, SGV->getType()->getElementType(), + SGV->isConstant(), NewLinkage, /*init*/0, + DGV->getName(), 0, false, + SGV->getType()->getAddressSpace()); + + // Propagate alignment, section, and visibility info. + CopyGVAttributes(NewDGV, SGV); + DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDGV, + DGV->getType())); + + // DGV will conflict with NewDGV because they both had the same + // name. We must erase this now so ForceRenaming doesn't assert + // because DGV might not have internal linkage. + if (GlobalVariable *Var = dyn_cast<GlobalVariable>(DGV)) + Var->eraseFromParent(); + else + cast<Function>(DGV)->eraseFromParent(); + + // If the symbol table renamed the global, but it is an externally visible + // symbol, DGV must be an existing global with internal linkage. Rename. + if (NewDGV->getName() != SGV->getName() && !NewDGV->hasLocalLinkage()) + ForceRenaming(NewDGV, SGV->getName()); + + // Inherit const as appropriate. + NewDGV->setConstant(SGV->isConstant()); + + // Make sure to remember this mapping. + ValueMap[SGV] = NewDGV; + continue; + } + + // Not "link from source", keep the one in the DestModule and remap the + // input onto it. + + // Special case for const propagation. + if (GlobalVariable *DGVar = dyn_cast<GlobalVariable>(DGV)) + if (DGVar->isDeclaration() && SGV->isConstant() && !DGVar->isConstant()) + DGVar->setConstant(true); + + // SGV is global, but DGV is alias. + if (isa<GlobalAlias>(DGV)) { + // The only valid mappings are: + // - SGV is external declaration, which is effectively a no-op. + // - SGV is weak, when we just need to throw SGV out. + if (!SGV->isDeclaration() && !SGV->isWeakForLinker()) + return Error(Err, "Global-Alias Collision on '" + SGV->getName() + + "': symbol multiple defined"); + } + + // Set calculated linkage + DGV->setLinkage(NewLinkage); + + // Make sure to remember this mapping... + ValueMap[SGV] = ConstantExpr::getBitCast(DGV, SGV->getType()); + } + return false; +} + +static GlobalValue::LinkageTypes +CalculateAliasLinkage(const GlobalValue *SGV, const GlobalValue *DGV) { + GlobalValue::LinkageTypes SL = SGV->getLinkage(); + GlobalValue::LinkageTypes DL = DGV->getLinkage(); + if (SL == GlobalValue::ExternalLinkage || DL == GlobalValue::ExternalLinkage) + return GlobalValue::ExternalLinkage; + else if (SL == GlobalValue::WeakAnyLinkage || + DL == GlobalValue::WeakAnyLinkage) + return GlobalValue::WeakAnyLinkage; + else if (SL == GlobalValue::WeakODRLinkage || + DL == GlobalValue::WeakODRLinkage) + return GlobalValue::WeakODRLinkage; + else if (SL == GlobalValue::InternalLinkage && + DL == GlobalValue::InternalLinkage) + return GlobalValue::InternalLinkage; + else if (SL == GlobalValue::LinkerPrivateLinkage && + DL == GlobalValue::LinkerPrivateLinkage) + return GlobalValue::LinkerPrivateLinkage; + else { + assert (SL == GlobalValue::PrivateLinkage && + DL == GlobalValue::PrivateLinkage && "Unexpected linkage type"); + return GlobalValue::PrivateLinkage; + } +} + +// LinkAlias - Loop through the alias in the src module and link them into the +// dest module. We're assuming, that all functions/global variables were already +// linked in. +static bool LinkAlias(Module *Dest, const Module *Src, + std::map<const Value*, Value*> &ValueMap, + std::string *Err) { + // Loop over all alias in the src module + for (Module::const_alias_iterator I = Src->alias_begin(), + E = Src->alias_end(); I != E; ++I) { + const GlobalAlias *SGA = I; + const GlobalValue *SAliasee = SGA->getAliasedGlobal(); + GlobalAlias *NewGA = NULL; + + // Globals were already linked, thus we can just query ValueMap for variant + // of SAliasee in Dest. + std::map<const Value*,Value*>::const_iterator VMI = ValueMap.find(SAliasee); + assert(VMI != ValueMap.end() && "Aliasee not linked"); + GlobalValue* DAliasee = cast<GlobalValue>(VMI->second); + GlobalValue* DGV = NULL; + + // Try to find something 'similar' to SGA in destination module. + if (!DGV && !SGA->hasLocalLinkage()) { + DGV = Dest->getNamedAlias(SGA->getName()); + + // If types don't agree due to opaque types, try to resolve them. + if (DGV && DGV->getType() != SGA->getType()) + RecursiveResolveTypes(SGA->getType(), DGV->getType()); + } + + if (!DGV && !SGA->hasLocalLinkage()) { + DGV = Dest->getGlobalVariable(SGA->getName()); + + // If types don't agree due to opaque types, try to resolve them. + if (DGV && DGV->getType() != SGA->getType()) + RecursiveResolveTypes(SGA->getType(), DGV->getType()); + } + + if (!DGV && !SGA->hasLocalLinkage()) { + DGV = Dest->getFunction(SGA->getName()); + + // If types don't agree due to opaque types, try to resolve them. + if (DGV && DGV->getType() != SGA->getType()) + RecursiveResolveTypes(SGA->getType(), DGV->getType()); + } + + // No linking to be performed on internal stuff. + if (DGV && DGV->hasLocalLinkage()) + DGV = NULL; + + if (GlobalAlias *DGA = dyn_cast_or_null<GlobalAlias>(DGV)) { + // Types are known to be the same, check whether aliasees equal. As + // globals are already linked we just need query ValueMap to find the + // mapping. + if (DAliasee == DGA->getAliasedGlobal()) { + // This is just two copies of the same alias. Propagate linkage, if + // necessary. + DGA->setLinkage(CalculateAliasLinkage(SGA, DGA)); + + NewGA = DGA; + // Proceed to 'common' steps + } else + return Error(Err, "Alias Collision on '" + SGA->getName()+ + "': aliases have different aliasees"); + } else if (GlobalVariable *DGVar = dyn_cast_or_null<GlobalVariable>(DGV)) { + // The only allowed way is to link alias with external declaration or weak + // symbol.. + if (DGVar->isDeclaration() || DGVar->isWeakForLinker()) { + // But only if aliasee is global too... + if (!isa<GlobalVariable>(DAliasee)) + return Error(Err, "Global-Alias Collision on '" + SGA->getName() + + "': aliasee is not global variable"); + + NewGA = new GlobalAlias(SGA->getType(), SGA->getLinkage(), + SGA->getName(), DAliasee, Dest); + CopyGVAttributes(NewGA, SGA); + + // Any uses of DGV need to change to NewGA, with cast, if needed. + if (SGA->getType() != DGVar->getType()) + DGVar->replaceAllUsesWith(ConstantExpr::getBitCast(NewGA, + DGVar->getType())); + else + DGVar->replaceAllUsesWith(NewGA); + + // DGVar will conflict with NewGA because they both had the same + // name. We must erase this now so ForceRenaming doesn't assert + // because DGV might not have internal linkage. + DGVar->eraseFromParent(); + + // Proceed to 'common' steps + } else + return Error(Err, "Global-Alias Collision on '" + SGA->getName() + + "': symbol multiple defined"); + } else if (Function *DF = dyn_cast_or_null<Function>(DGV)) { + // The only allowed way is to link alias with external declaration or weak + // symbol... + if (DF->isDeclaration() || DF->isWeakForLinker()) { + // But only if aliasee is function too... + if (!isa<Function>(DAliasee)) + return Error(Err, "Function-Alias Collision on '" + SGA->getName() + + "': aliasee is not function"); + + NewGA = new GlobalAlias(SGA->getType(), SGA->getLinkage(), + SGA->getName(), DAliasee, Dest); + CopyGVAttributes(NewGA, SGA); + + // Any uses of DF need to change to NewGA, with cast, if needed. + if (SGA->getType() != DF->getType()) + DF->replaceAllUsesWith(ConstantExpr::getBitCast(NewGA, + DF->getType())); + else + DF->replaceAllUsesWith(NewGA); + + // DF will conflict with NewGA because they both had the same + // name. We must erase this now so ForceRenaming doesn't assert + // because DF might not have internal linkage. + DF->eraseFromParent(); + + // Proceed to 'common' steps + } else + return Error(Err, "Function-Alias Collision on '" + SGA->getName() + + "': symbol multiple defined"); + } else { + // No linking to be performed, simply create an identical version of the + // alias over in the dest module... + Constant *Aliasee = DAliasee; + // Fixup aliases to bitcasts. Note that aliases to GEPs are still broken + // by this, but aliases to GEPs are broken to a lot of other things, so + // it's less important. + if (SGA->getType() != DAliasee->getType()) + Aliasee = ConstantExpr::getBitCast(DAliasee, SGA->getType()); + NewGA = new GlobalAlias(SGA->getType(), SGA->getLinkage(), + SGA->getName(), Aliasee, Dest); + CopyGVAttributes(NewGA, SGA); + + // Proceed to 'common' steps + } + + assert(NewGA && "No alias was created in destination module!"); + + // If the symbol table renamed the alias, but it is an externally visible + // symbol, DGA must be an global value with internal linkage. Rename it. + if (NewGA->getName() != SGA->getName() && + !NewGA->hasLocalLinkage()) + ForceRenaming(NewGA, SGA->getName()); + + // Remember this mapping so uses in the source module get remapped + // later by RemapOperand. + ValueMap[SGA] = NewGA; + } + + return false; +} + + +// LinkGlobalInits - Update the initializers in the Dest module now that all +// globals that may be referenced are in Dest. +static bool LinkGlobalInits(Module *Dest, const Module *Src, + std::map<const Value*, Value*> &ValueMap, + std::string *Err) { + // 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; + + if (SGV->hasInitializer()) { // Only process initialized GV's + // Figure out what the initializer looks like in the dest module... + Constant *SInit = + cast<Constant>(RemapOperand(SGV->getInitializer(), ValueMap)); + // Grab destination global variable or alias. + GlobalValue *DGV = cast<GlobalValue>(ValueMap[SGV]->stripPointerCasts()); + + // If dest if global variable, check that initializers match. + if (GlobalVariable *DGVar = dyn_cast<GlobalVariable>(DGV)) { + if (DGVar->hasInitializer()) { + if (SGV->hasExternalLinkage()) { + if (DGVar->getInitializer() != SInit) + return Error(Err, "Global Variable Collision on '" + + SGV->getName() + + "': global variables have different initializers"); + } else if (DGVar->isWeakForLinker()) { + // Nothing is required, mapped values will take the new global + // automatically. + } else if (SGV->isWeakForLinker()) { + // Nothing is required, mapped values will take the new global + // automatically. + } else if (DGVar->hasAppendingLinkage()) { + llvm_unreachable("Appending linkage unimplemented!"); + } else { + llvm_unreachable("Unknown linkage!"); + } + } else { + // Copy the initializer over now... + DGVar->setInitializer(SInit); + } + } else { + // Destination is alias, the only valid situation is when source is + // weak. Also, note, that we already checked linkage in LinkGlobals(), + // thus we assert here. + // FIXME: Should we weaken this assumption, 'dereference' alias and + // check for initializer of aliasee? + assert(SGV->isWeakForLinker()); + } + } + } + return false; +} + +// LinkFunctionProtos - Link the functions together between the two modules, +// without doing function bodies... this just adds external function prototypes +// to the Dest function... +// +static bool LinkFunctionProtos(Module *Dest, const Module *Src, + std::map<const Value*, Value*> &ValueMap, + std::string *Err) { + ValueSymbolTable &DestSymTab = Dest->getValueSymbolTable(); + + // Loop over all of the functions in the src module, mapping them over + for (Module::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) { + const Function *SF = I; // SrcFunction + GlobalValue *DGV = 0; + + // Check to see if may have to link the function with the global, alias or + // function. + if (SF->hasName() && !SF->hasLocalLinkage()) + DGV = cast_or_null<GlobalValue>(DestSymTab.lookup(SF->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() != SF->getType()) + RecursiveResolveTypes(SF->getType(), DGV->getType()); + + GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; + bool LinkFromSrc = false; + if (GetLinkageResult(DGV, SF, NewLinkage, LinkFromSrc, Err)) + return true; + + // If there is no linkage to be performed, just bring over SF without + // modifying it. + if (DGV == 0) { + // Function does not already exist, simply insert an function signature + // identical to SF into the dest module. + Function *NewDF = Function::Create(SF->getFunctionType(), + SF->getLinkage(), + SF->getName(), Dest); + CopyGVAttributes(NewDF, SF); + + // If the LLVM runtime renamed the function, but it is an externally + // visible symbol, DF must be an existing function with internal linkage. + // Rename it. + if (!NewDF->hasLocalLinkage() && NewDF->getName() != SF->getName()) + ForceRenaming(NewDF, SF->getName()); + + // ... and remember this mapping... + ValueMap[SF] = NewDF; + continue; + } + + // If the visibilities of the symbols disagree and the destination is a + // prototype, take the visibility of its input. + if (DGV->isDeclaration()) + DGV->setVisibility(SF->getVisibility()); + + if (LinkFromSrc) { + if (isa<GlobalAlias>(DGV)) + return Error(Err, "Function-Alias Collision on '" + SF->getName() + + "': symbol multiple defined"); + + // We have a definition of the same name but different type in the + // source module. Copy the prototype to the destination and replace + // uses of the destination's prototype with the new prototype. + Function *NewDF = Function::Create(SF->getFunctionType(), NewLinkage, + SF->getName(), Dest); + CopyGVAttributes(NewDF, SF); + + // Any uses of DF need to change to NewDF, with cast + DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDF, + DGV->getType())); + + // DF will conflict with NewDF because they both had the same. We must + // erase this now so ForceRenaming doesn't assert because DF might + // not have internal linkage. + if (GlobalVariable *Var = dyn_cast<GlobalVariable>(DGV)) + Var->eraseFromParent(); + else + cast<Function>(DGV)->eraseFromParent(); + + // If the symbol table renamed the function, but it is an externally + // visible symbol, DF must be an existing function with internal + // linkage. Rename it. + if (NewDF->getName() != SF->getName() && !NewDF->hasLocalLinkage()) + ForceRenaming(NewDF, SF->getName()); + + // Remember this mapping so uses in the source module get remapped + // later by RemapOperand. + ValueMap[SF] = NewDF; + continue; + } + + // Not "link from source", keep the one in the DestModule and remap the + // input onto it. + + if (isa<GlobalAlias>(DGV)) { + // The only valid mappings are: + // - SF is external declaration, which is effectively a no-op. + // - SF is weak, when we just need to throw SF out. + if (!SF->isDeclaration() && !SF->isWeakForLinker()) + return Error(Err, "Function-Alias Collision on '" + SF->getName() + + "': symbol multiple defined"); + } + + // Set calculated linkage + DGV->setLinkage(NewLinkage); + + // Make sure to remember this mapping. + ValueMap[SF] = ConstantExpr::getBitCast(DGV, SF->getType()); + } + return false; +} + +// 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. +static bool LinkFunctionBody(Function *Dest, Function *Src, + std::map<const Value*, Value*> &ValueMap, + std::string *Err) { + assert(Src && Dest && Dest->isDeclaration() && !Src->isDeclaration()); + + // Go through and convert function arguments over, remembering the mapping. + Function::arg_iterator DI = Dest->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 information over... + + // Add a mapping to our local map + ValueMap[I] = DI; + } + + // Splice the body of the source function into the dest function. + Dest->getBasicBlockList().splice(Dest->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 = Dest->begin(), BE = Dest->end(); BB != BE; ++BB) + for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) + for (Instruction::op_iterator OI = I->op_begin(), OE = I->op_end(); + OI != OE; ++OI) + if (!isa<Instruction>(*OI) && !isa<BasicBlock>(*OI)) + *OI = RemapOperand(*OI, ValueMap); + + // 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); + + return false; +} + + +// LinkFunctionBodies - Link in the function bodies that are defined in the +// source module into the DestModule. This consists basically of copying the +// function over and fixing up references to values. +static bool LinkFunctionBodies(Module *Dest, Module *Src, + std::map<const Value*, Value*> &ValueMap, + std::string *Err) { + + // Loop over all of the functions in the src module, mapping them over as we + // go + for (Module::iterator SF = Src->begin(), E = Src->end(); SF != E; ++SF) { + if (!SF->isDeclaration()) { // No body if function is external + Function *DF = dyn_cast<Function>(ValueMap[SF]); // Destination function + + // DF not external SF external? + if (DF && DF->isDeclaration()) + // Only provide the function body if there isn't one already. + if (LinkFunctionBody(DF, SF, ValueMap, Err)) + return true; + } + } + return false; +} + +// LinkAppendingVars - If there were any appending global variables, link them +// together now. Return true on error. +static bool LinkAppendingVars(Module *M, + std::multimap<std::string, GlobalVariable *> &AppendingVars, + std::string *ErrorMsg) { + if (AppendingVars.empty()) return false; // Nothing to do. + + // Loop over the multimap of appending vars, processing any variables with the + // same name, forming a new appending global variable with both of the + // initializers merged together, then rewrite references to the old variables + // and delete them. + std::vector<Constant*> Inits; + while (AppendingVars.size() > 1) { + // Get the first two elements in the map... + std::multimap<std::string, + GlobalVariable*>::iterator Second = AppendingVars.begin(), First=Second++; + + // If the first two elements are for different names, there is no pair... + // Otherwise there is a pair, so link them together... + if (First->first == Second->first) { + GlobalVariable *G1 = First->second, *G2 = Second->second; + const ArrayType *T1 = cast<ArrayType>(G1->getType()->getElementType()); + const ArrayType *T2 = cast<ArrayType>(G2->getType()->getElementType()); + + // Check to see that they two arrays agree on type... + if (T1->getElementType() != T2->getElementType()) + return Error(ErrorMsg, + "Appending variables with different element types need to be linked!"); + if (G1->isConstant() != G2->isConstant()) + return Error(ErrorMsg, + "Appending variables linked with different const'ness!"); + + if (G1->getAlignment() != G2->getAlignment()) + return Error(ErrorMsg, + "Appending variables with different alignment need to be linked!"); + + if (G1->getVisibility() != G2->getVisibility()) + return Error(ErrorMsg, + "Appending variables with different visibility need to be linked!"); + + if (G1->getSection() != G2->getSection()) + return Error(ErrorMsg, + "Appending variables with different section name need to be linked!"); + + unsigned NewSize = T1->getNumElements() + T2->getNumElements(); + ArrayType *NewType = ArrayType::get(T1->getElementType(), + NewSize); + + G1->setName(""); // Clear G1's name in case of a conflict! + + // Create the new global variable... + GlobalVariable *NG = + new GlobalVariable(*M, NewType, G1->isConstant(), G1->getLinkage(), + /*init*/0, First->first, 0, G1->isThreadLocal(), + G1->getType()->getAddressSpace()); + + // Propagate alignment, visibility and section info. + CopyGVAttributes(NG, G1); + + // Merge the initializer... + Inits.reserve(NewSize); + if (ConstantArray *I = dyn_cast<ConstantArray>(G1->getInitializer())) { + for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i) + Inits.push_back(I->getOperand(i)); + } else { + assert(isa<ConstantAggregateZero>(G1->getInitializer())); + Constant *CV = Constant::getNullValue(T1->getElementType()); + for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i) + Inits.push_back(CV); + } + if (ConstantArray *I = dyn_cast<ConstantArray>(G2->getInitializer())) { + for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i) + Inits.push_back(I->getOperand(i)); + } else { + assert(isa<ConstantAggregateZero>(G2->getInitializer())); + Constant *CV = Constant::getNullValue(T2->getElementType()); + for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i) + Inits.push_back(CV); + } + NG->setInitializer(ConstantArray::get(NewType, Inits)); + Inits.clear(); + + // Replace any uses of the two global variables with uses of the new + // global... + + // FIXME: This should rewrite simple/straight-forward uses such as + // getelementptr instructions to not use the Cast! + G1->replaceAllUsesWith(ConstantExpr::getBitCast(NG, + G1->getType())); + G2->replaceAllUsesWith(ConstantExpr::getBitCast(NG, + G2->getType())); + + // Remove the two globals from the module now... + M->getGlobalList().erase(G1); + M->getGlobalList().erase(G2); + + // Put the new global into the AppendingVars map so that we can handle + // linking of more than two vars... + Second->second = NG; + } + AppendingVars.erase(First); + } + + return false; +} + +static bool ResolveAliases(Module *Dest) { + for (Module::alias_iterator I = Dest->alias_begin(), E = Dest->alias_end(); + I != E; ++I) + // We can't sue resolveGlobalAlias here because we need to preserve + // bitcasts and GEPs. + if (const Constant *C = I->getAliasee()) { + while (dyn_cast<GlobalAlias>(C)) + C = cast<GlobalAlias>(C)->getAliasee(); + const GlobalValue *GV = dyn_cast<GlobalValue>(C); + if (C != I && !(GV && GV->isDeclaration())) + I->replaceAllUsesWith(const_cast<Constant*>(C)); + } + + return false; +} + +// 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, std::string *ErrorMsg) { + assert(Dest != 0 && "Invalid Destination module"); + assert(Src != 0 && "Invalid Source Module"); + + if (Dest->getDataLayout().empty()) { + if (!Src->getDataLayout().empty()) { + Dest->setDataLayout(Src->getDataLayout()); + } else { + std::string DataLayout; + + if (Dest->getEndianness() == Module::AnyEndianness) { + if (Src->getEndianness() == Module::BigEndian) + DataLayout.append("E"); + else if (Src->getEndianness() == Module::LittleEndian) + DataLayout.append("e"); + } + + if (Dest->getPointerSize() == Module::AnyPointerSize) { + if (Src->getPointerSize() == Module::Pointer64) + DataLayout.append(DataLayout.length() == 0 ? "p:64:64" : "-p:64:64"); + else if (Src->getPointerSize() == Module::Pointer32) + DataLayout.append(DataLayout.length() == 0 ? "p:32:32" : "-p:32:32"); + } + Dest->setDataLayout(DataLayout); + } + } + + // Copy the target triple from the source to dest if the dest's is empty. + if (Dest->getTargetTriple().empty() && !Src->getTargetTriple().empty()) + Dest->setTargetTriple(Src->getTargetTriple()); + + if (!Src->getDataLayout().empty() && !Dest->getDataLayout().empty() && + Src->getDataLayout() != Dest->getDataLayout()) + errs() << "WARNING: Linking two modules of different data layouts!\n"; + if (!Src->getTargetTriple().empty() && + Dest->getTargetTriple() != Src->getTargetTriple()) + errs() << "WARNING: Linking two modules of different target triples!\n"; + + // Append the module inline asm string. + if (!Src->getModuleInlineAsm().empty()) { + if (Dest->getModuleInlineAsm().empty()) + Dest->setModuleInlineAsm(Src->getModuleInlineAsm()); + else + Dest->setModuleInlineAsm(Dest->getModuleInlineAsm()+"\n"+ + Src->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 = Src->lib_begin(), SE = Src->lib_end(); + SI != SE; ++SI) + Dest->addLibrary(*SI); + + // 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. + if (LinkTypes(Dest, Src, ErrorMsg)) + return true; + + // ValueMap - Mapping of values from what they used to be in Src, to what they + // are now in Dest. + std::map<const Value*, Value*> ValueMap; + + // AppendingVars - Keep track of global variables in the destination module + // with appending linkage. After the module is linked together, they are + // appended and the module is rewritten. + std::multimap<std::string, GlobalVariable *> AppendingVars; + for (Module::global_iterator I = Dest->global_begin(), E = Dest->global_end(); + I != E; ++I) { + // Add all of the appending globals already in the Dest module to + // AppendingVars. + if (I->hasAppendingLinkage()) + AppendingVars.insert(std::make_pair(I->getName(), I)); + } + + // Insert all of the named mdnoes in Src into the Dest module. + LinkNamedMDNodes(Dest, Src); + + // Insert all of the globals in src into the Dest module... without linking + // initializers (which could refer to functions not yet mapped over). + if (LinkGlobals(Dest, Src, ValueMap, AppendingVars, ErrorMsg)) + return true; + + // Link the functions together between the two modules, without doing function + // bodies... this just adds external function prototypes to the Dest + // 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. + if (LinkFunctionProtos(Dest, Src, ValueMap, ErrorMsg)) + return true; + + // If there were any alias, link them now. We really need to do this now, + // because all of the aliases that may be referenced need to be available in + // ValueMap + if (LinkAlias(Dest, Src, ValueMap, ErrorMsg)) return true; + + // Update the initializers in the Dest module now that all globals that may + // be referenced are in Dest. + if (LinkGlobalInits(Dest, Src, ValueMap, ErrorMsg)) return true; + + // Link in the function bodies that are defined in the source module into the + // DestModule. This consists basically of copying the function over and + // fixing up references to values. + if (LinkFunctionBodies(Dest, Src, ValueMap, ErrorMsg)) return true; + + // If there were any appending global variables, link them together now. + if (LinkAppendingVars(Dest, AppendingVars, ErrorMsg)) return true; + + // Resolve all uses of aliases with aliasees + if (ResolveAliases(Dest)) return true; + + // 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. + sys::Path modId; + modId.set(Src->getModuleIdentifier()); + if (!modId.isEmpty()) + Dest->removeLibrary(modId.getBasename()); + + return false; +} + +// vim: sw=2 |
