//===- Linker.cpp - Module Linker Implementation --------------------------===// // // 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/Transforms/Utils/Linker.h" #include "llvm/Module.h" #include "llvm/SymbolTable.h" #include "llvm/DerivedTypes.h" #include "llvm/iOther.h" #include "llvm/Constants.h" // 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 std::string &Message) { if (E) *E = Message; return true; } // ResolveTypes - Attempt to link the two specified types together. Return true // if there is an error and they cannot yet be linked. // static bool ResolveTypes(const Type *DestTy, const Type *SrcTy, SymbolTable *DestST, const std::string &Name) { if (DestTy == SrcTy) return false; // If already equal, noop // Does the type already exist in the module? if (DestTy && !isa(DestTy)) { // Yup, the type already exists... if (const OpaqueType *OT = dyn_cast(SrcTy)) { const_cast(OT)->refineAbstractTypeTo(DestTy); } else { return true; // Cannot link types... neither is opaque and not-equal } } else { // Type not in dest module. Add it now. if (DestTy) // Type _is_ in module, just opaque... const_cast(cast(DestTy)) ->refineAbstractTypeTo(SrcTy); else if (!Name.empty()) DestST->insert(Name, const_cast(SrcTy)); } return false; } static const FunctionType *getFT(const PATypeHolder &TH) { return cast(TH.get()); } static const StructType *getST(const PATypeHolder &TH) { return cast(TH.get()); } // 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 PATypeHolder &DestTy, const PATypeHolder &SrcTy, SymbolTable *DestST, const std::string &Name, std::vector > &Pointers) { const Type *SrcTyT = SrcTy.get(); const Type *DestTyT = DestTy.get(); if (DestTyT == SrcTyT) return false; // If already equal, noop // If we found our opaque type, resolve it now! if (isa(DestTyT) || isa(SrcTyT)) return ResolveTypes(DestTyT, SrcTyT, DestST, Name); // Two types cannot be resolved together if they are of different primitive // type. For example, we cannot resolve an int to a float. if (DestTyT->getPrimitiveID() != SrcTyT->getPrimitiveID()) return true; // Otherwise, resolve the used type used by this derived type... switch (DestTyT->getPrimitiveID()) { case Type::FunctionTyID: { if (cast(DestTyT)->isVarArg() != cast(SrcTyT)->isVarArg()) return true; for (unsigned i = 0, e = getFT(DestTy)->getNumContainedTypes(); i != e; ++i) if (RecursiveResolveTypesI(getFT(DestTy)->getContainedType(i), getFT(SrcTy)->getContainedType(i), DestST, "", Pointers)) return true; return false; } case Type::StructTyID: { if (getST(DestTy)->getNumContainedTypes() != getST(SrcTy)->getNumContainedTypes()) return 1; for (unsigned i = 0, e = getST(DestTy)->getNumContainedTypes(); i != e; ++i) if (RecursiveResolveTypesI(getST(DestTy)->getContainedType(i), getST(SrcTy)->getContainedType(i), DestST, "", Pointers)) return true; return false; } case Type::ArrayTyID: { const ArrayType *DAT = cast(DestTy.get()); const ArrayType *SAT = cast(SrcTy.get()); if (DAT->getNumElements() != SAT->getNumElements()) return true; return RecursiveResolveTypesI(DAT->getElementType(), SAT->getElementType(), DestST, "", Pointers); } case Type::PointerTyID: { // 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... // for (unsigned i = 0, e = Pointers.size(); i != e; ++i) if (Pointers[i].first == DestTy) return Pointers[i].second != SrcTy; // Otherwise, add the current pointers to the vector to stop recursion on // this pair. Pointers.push_back(std::make_pair(DestTyT, SrcTyT)); bool Result = RecursiveResolveTypesI(cast(DestTy.get())->getElementType(), cast(SrcTy.get())->getElementType(), DestST, "", Pointers); Pointers.pop_back(); return Result; } default: assert(0 && "Unexpected type!"); return true; } } static bool RecursiveResolveTypes(const PATypeHolder &DestTy, const PATypeHolder &SrcTy, SymbolTable *DestST, const std::string &Name){ std::vector > PointerTypes; return RecursiveResolveTypesI(DestTy, SrcTy, DestST, Name, 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) { SymbolTable *DestST = &Dest->getSymbolTable(); const SymbolTable *SrcST = &Src->getSymbolTable(); // Look for a type plane for Type's... SymbolTable::const_iterator PI = SrcST->find(Type::TypeTy); if (PI == SrcST->end()) return false; // No named types, do nothing. // Some types cannot be resolved immediately becuse they depend on other types // being resolved to each other first. This contains a list of types we are // waiting to recheck. std::vector DelayedTypesToResolve; const SymbolTable::VarMap &VM = PI->second; for (SymbolTable::type_const_iterator I = VM.begin(), E = VM.end(); I != E; ++I) { const std::string &Name = I->first; Type *RHS = cast(I->second); // Check to see if this type name is already in the dest module... Type *Entry = cast_or_null(DestST->lookup(Type::TypeTy, Name)); if (ResolveTypes(Entry, RHS, DestST, Name)) { // 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 = cast(VM.find(Name)->second); Type *T2 = cast(DestST->lookup(Type::TypeTy, Name)); if (!ResolveTypes(T2, T1, DestST, Name)) { // 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]; PATypeHolder T1(cast(VM.find(Name)->second)); PATypeHolder T2(cast(DestST->lookup(Type::TypeTy, Name))); if (!RecursiveResolveTypes(T2, T1, DestST, 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. // Report the error. if (DelayedTypesToResolve.size() == OldSize) { // Build up an error message of all of the mismatched types. std::string ErrorMessage; for (unsigned i = 0, e = DelayedTypesToResolve.size(); i != e; ++i) { const std::string &Name = DelayedTypesToResolve[i]; const Type *T1 = cast(VM.find(Name)->second); const Type *T2 = cast(DestST->lookup(Type::TypeTy, Name)); ErrorMessage += " Type named '" + Name + "' conflicts.\n Src='" + T1->getDescription() + "'.\n Dest='" + T2->getDescription() + "'\n"; } return Error(Err, "Type conflict between types in modules:\n" + ErrorMessage); } } } return false; } static void PrintMap(const std::map &M) { for (std::map::const_iterator I = M.begin(), E =M.end(); I != E; ++I) { std::cerr << " Fr: " << (void*)I->first << " "; I->first->dump(); std::cerr << " To: " << (void*)I->second << " "; I->second->dump(); std::cerr << "\n"; } } // RemapOperand - Use LocalMap and GlobalMap to convert references from one // module to another. This is somewhat sophisticated in that it can // automatically handle constant references correctly as well... // static Value *RemapOperand(const Value *In, std::map &LocalMap, std::map *GlobalMap) { std::map::const_iterator I = LocalMap.find(In); if (I != LocalMap.end()) return I->second; if (GlobalMap) { I = GlobalMap->find(In); if (I != GlobalMap->end()) return I->second; } // Check to see if it's a constant that we are interesting in transforming... if (const Constant *CPV = dyn_cast(In)) { if (!isa(CPV->getType()) && !isa(CPV)) return const_cast(CPV); // Simple constants stay identical... Constant *Result = 0; if (const ConstantArray *CPA = dyn_cast(CPV)) { const std::vector &Ops = CPA->getValues(); std::vector Operands(Ops.size()); for (unsigned i = 0, e = Ops.size(); i != e; ++i) Operands[i] = cast(RemapOperand(Ops[i], LocalMap, GlobalMap)); Result = ConstantArray::get(cast(CPA->getType()), Operands); } else if (const ConstantStruct *CPS = dyn_cast(CPV)) { const std::vector &Ops = CPS->getValues(); std::vector Operands(Ops.size()); for (unsigned i = 0; i < Ops.size(); ++i) Operands[i] = cast(RemapOperand(Ops[i], LocalMap, GlobalMap)); Result = ConstantStruct::get(cast(CPS->getType()), Operands); } else if (isa(CPV)) { Result = const_cast(CPV); } else if (const ConstantPointerRef *CPR = dyn_cast(CPV)) { Value *V = RemapOperand(CPR->getValue(), LocalMap, GlobalMap); Result = ConstantPointerRef::get(cast(V)); } else if (const ConstantExpr *CE = dyn_cast(CPV)) { if (CE->getOpcode() == Instruction::GetElementPtr) { Value *Ptr = RemapOperand(CE->getOperand(0), LocalMap, GlobalMap); std::vector Indices; Indices.reserve(CE->getNumOperands()-1); for (unsigned i = 1, e = CE->getNumOperands(); i != e; ++i) Indices.push_back(cast(RemapOperand(CE->getOperand(i), LocalMap, GlobalMap))); Result = ConstantExpr::getGetElementPtr(cast(Ptr), Indices); } else if (CE->getNumOperands() == 1) { // Cast instruction assert(CE->getOpcode() == Instruction::Cast); Value *V = RemapOperand(CE->getOperand(0), LocalMap, GlobalMap); Result = ConstantExpr::getCast(cast(V), CE->getType()); } else if (CE->getNumOperands() == 2) { // Binary operator... Value *V1 = RemapOperand(CE->getOperand(0), LocalMap, GlobalMap); Value *V2 = RemapOperand(CE->getOperand(1), LocalMap, GlobalMap); Result = ConstantExpr::get(CE->getOpcode(), cast(V1), cast(V2)); } else { assert(0 && "Unknown constant expr type!"); } } else { assert(0 && "Unknown type of derived type constant value!"); } // Cache the mapping in our local map structure... if (GlobalMap) GlobalMap->insert(std::make_pair(In, Result)); else LocalMap.insert(std::make_pair(In, Result)); return Result; } std::cerr << "XXX LocalMap: \n"; PrintMap(LocalMap); if (GlobalMap) { std::cerr << "XXX GlobalMap: \n"; PrintMap(*GlobalMap); } std::cerr << "Couldn't remap value: " << (void*)In << " " << *In << "\n"; assert(0 && "Couldn't remap value!"); return 0; } /// FindGlobalNamed - Look in the specified symbol table for a global with the /// specified name and type. If an exactly matching global does not exist, see /// if there is a global which is "type compatible" with the specified /// name/type. This allows us to resolve things like '%x = global int*' with /// '%x = global opaque*'. /// static GlobalValue *FindGlobalNamed(const std::string &Name, const Type *Ty, SymbolTable *ST) { // See if an exact match exists in the symbol table... if (Value *V = ST->lookup(Ty, Name)) return cast(V); // It doesn't exist exactly, scan through all of the type planes in the symbol // table, checking each of them for a type-compatible version. // for (SymbolTable::iterator I = ST->begin(), E = ST->end(); I != E; ++I) if (I->first != Type::TypeTy) { SymbolTable::VarMap &VM = I->second; // Does this type plane contain an entry with the specified name? SymbolTable::type_iterator TI = VM.find(Name); if (TI != VM.end()) { // Determine whether we can fold the two types together, resolving them. // If so, we can use this value. if (!RecursiveResolveTypes(Ty, I->first, ST, "")) return cast(TI->second); } } return 0; // Otherwise, nothing could be found. } // 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 &ValueMap, std::multimap &AppendingVars, std::string *Err) { // We will need a module level symbol table if the src module has a module // level symbol table... SymbolTable *ST = (SymbolTable*)&Dest->getSymbolTable(); // Loop over all of the globals in the src module, mapping them over as we go // for (Module::const_giterator I = Src->gbegin(), E = Src->gend(); I != E; ++I){ const GlobalVariable *SGV = I; GlobalVariable *DGV = 0; if (SGV->hasName()) { // A same named thing is a global variable, because the only two things // that may be in a module level symbol table are Global Vars and // Functions, and they both have distinct, nonoverlapping, possible types. // DGV = cast_or_null(FindGlobalNamed(SGV->getName(), SGV->getType(), ST)); } assert(SGV->hasInitializer() || SGV->hasExternalLinkage() && "Global must either be external or have an initializer!"); bool SGExtern = SGV->isExternal(); bool DGExtern = DGV ? DGV->isExternal() : false; if (!DGV || DGV->hasInternalLinkage() || SGV->hasInternalLinkage()) { // 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(SGV->getType()->getElementType(), SGV->isConstant(), SGV->getLinkage(), /*init*/0, SGV->getName(), Dest); // 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->getName() != SGV->getName() && !NewDGV->hasInternalLinkage()){ assert(DGV && DGV->getName() == SGV->getName() && DGV->hasInternalLinkage()); DGV->setName(""); NewDGV->setName(SGV->getName()); // Force the name back DGV->setName(SGV->getName()); // This will cause a renaming assert(NewDGV->getName() == SGV->getName() && DGV->getName() != SGV->getName()); } // Make sure to remember this mapping... ValueMap.insert(std::make_pair(SGV, NewDGV)); if (SGV->hasAppendingLinkage()) // Keep track that this is an appending variable... AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV)); } else if (SGV->isExternal()) { // If SGV is external or if both SGV & DGV are external.. Just link the // external globals, we aren't adding anything. ValueMap.insert(std::make_pair(SGV, DGV)); } else if (DGV->isExternal()) { // If DGV is external but SGV is not... ValueMap.insert(std::make_pair(SGV, DGV)); DGV->setLinkage(SGV->getLinkage()); // Inherit linkage! } else if (SGV->getLinkage() != DGV->getLinkage()) { return Error(Err, "Global variables named '" + SGV->getName() + "' have different linkage specifiers!"); } else if (SGV->hasExternalLinkage()) { // Allow linking two exactly identical external global variables... if (SGV->isConstant() != DGV->isConstant() || SGV->getInitializer() != DGV->getInitializer()) return Error(Err, "Global Variable Collision on '" + SGV->getType()->getDescription() + " %" + SGV->getName() + "' - Global variables differ in const'ness"); ValueMap.insert(std::make_pair(SGV, DGV)); } else if (SGV->hasLinkOnceLinkage()) { // If the global variable has a name, and that name is already in use in // the Dest module, make sure that the name is a compatible global // variable... // // Check to see if the two GV's have the same Const'ness... if (SGV->isConstant() != DGV->isConstant()) return Error(Err, "Global Variable Collision on '" + SGV->getType()->getDescription() + " %" + SGV->getName() + "' - Global variables differ in const'ness"); // Okay, everything is cool, remember the mapping... ValueMap.insert(std::make_pair(SGV, DGV)); } else if (SGV->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(SGV->getType()->getElementType(), SGV->isConstant(), SGV->getLinkage(), /*init*/0, "", Dest); // Make sure to remember this mapping... ValueMap.insert(std::make_pair(SGV, NewDGV)); // Keep track that this is an appending variable... AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV)); } else { assert(0 && "Unknown linkage!"); } } 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 &ValueMap, std::string *Err) { // Loop over all of the globals in the src module, mapping them over as we go // for (Module::const_giterator I = Src->gbegin(), E = Src->gend(); 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(RemapOperand(SGV->getInitializer(), ValueMap, 0)); GlobalVariable *DGV = cast(ValueMap[SGV]); if (DGV->hasInitializer()) { assert(SGV->getLinkage() == DGV->getLinkage()); if (SGV->hasExternalLinkage()) { if (DGV->getInitializer() != SInit) return Error(Err, "Global Variable Collision on '" + SGV->getType()->getDescription() +"':%"+SGV->getName()+ " - Global variables have different initializers"); } else if (DGV->hasLinkOnceLinkage()) { // Nothing is required, mapped values will take the new global // automatically. } else if (DGV->hasAppendingLinkage()) { assert(0 && "Appending linkage unimplemented!"); } else { assert(0 && "Unknown linkage!"); } } else { // Copy the initializer over now... DGV->setInitializer(SInit); } } } 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 &ValueMap, std::string *Err) { SymbolTable *ST = (SymbolTable*)&Dest->getSymbolTable(); // Loop over all of the functions in the src module, mapping them over as we // go // for (Module::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) { const Function *SF = I; // SrcFunction Function *DF = 0; if (SF->hasName()) // The same named thing is a Function, because the only two things // that may be in a module level symbol table are Global Vars and // Functions, and they both have distinct, nonoverlapping, possible types. // DF = cast_or_null(FindGlobalNamed(SF->getName(), SF->getType(), ST)); if (!DF || SF->hasInternalLinkage() || DF->hasInternalLinkage()) { // Function does not already exist, simply insert an function signature // identical to SF into the dest module... Function *NewDF = new Function(SF->getFunctionType(), SF->getLinkage(), SF->getName(), Dest); // 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->getName() != SF->getName() && !NewDF->hasInternalLinkage()) { assert(DF && DF->getName() == SF->getName() &&DF->hasInternalLinkage()); DF->setName(""); NewDF->setName(SF->getName()); // Force the name back DF->setName(SF->getName()); // This will cause a renaming assert(NewDF->getName() == SF->getName() && DF->getName() != SF->getName()); } // ... and remember this mapping... ValueMap.insert(std::make_pair(SF, NewDF)); } else if (SF->isExternal()) { // If SF is external or if both SF & DF are external.. Just link the // external functions, we aren't adding anything. ValueMap.insert(std::make_pair(SF, DF)); } else if (DF->isExternal()) { // If DF is external but SF is not... // Link the external functions, update linkage qualifiers ValueMap.insert(std::make_pair(SF, DF)); DF->setLinkage(SF->getLinkage()); } else if (SF->getLinkage() != DF->getLinkage()) { return Error(Err, "Functions named '" + SF->getName() + "' have different linkage specifiers!"); } else if (SF->hasExternalLinkage()) { // The function is defined in both modules!! return Error(Err, "Function '" + SF->getFunctionType()->getDescription() + "':\"" + SF->getName() + "\" - Function is already defined!"); } else if (SF->hasLinkOnceLinkage()) { // Completely ignore the source function. ValueMap.insert(std::make_pair(SF, DF)); } else { assert(0 && "Unknown linkage configuration found!"); } } 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, const Function *Src, std::map &GlobalMap, std::string *Err) { assert(Src && Dest && Dest->isExternal() && !Src->isExternal()); std::map LocalMap; // Map for function local values // Go through and convert function arguments over... Function::aiterator DI = Dest->abegin(); for (Function::const_aiterator I = Src->abegin(), E = Src->aend(); I != E; ++I, ++DI) { DI->setName(I->getName()); // Copy the name information over... // Add a mapping to our local map LocalMap.insert(std::make_pair(I, DI)); } // Loop over all of the basic blocks, copying the instructions over... // for (Function::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) { // Create new basic block and add to mapping and the Dest function... BasicBlock *DBB = new BasicBlock(I->getName(), Dest); LocalMap.insert(std::make_pair(I, DBB)); // Loop over all of the instructions in the src basic block, copying them // over. Note that this is broken in a strict sense because the cloned // instructions will still be referencing values in the Src module, not // the remapped values. In our case, however, we will not get caught and // so we can delay patching the values up until later... // for (BasicBlock::const_iterator II = I->begin(), IE = I->end(); II != IE; ++II) { Instruction *DI = II->clone(); DI->setName(II->getName()); DBB->getInstList().push_back(DI); LocalMap.insert(std::make_pair(II, DI)); } } // 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) *OI = RemapOperand(*OI, LocalMap, &GlobalMap); 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, const Module *Src, std::map &ValueMap, std::string *Err) { // Loop over all of the functions in the src module, mapping them over as we // go // for (Module::const_iterator SF = Src->begin(), E = Src->end(); SF != E; ++SF){ if (!SF->isExternal()) { // No body if function is external Function *DF = cast(ValueMap[SF]); // Destination function // DF not external SF external? if (!DF->isExternal()) { if (DF->hasLinkOnceLinkage()) continue; // No relinkage for link-once! if (Err) *Err = "Function '" + (SF->hasName() ? SF->getName() :std::string("")) + "' body multiply defined!"; return true; } 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 &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 Inits; while (AppendingVars.size() > 1) { // Get the first two elements in the map... std::multimap::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(G1->getType()->getElementType()); const ArrayType *T2 = cast(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!"); unsigned NewSize = T1->getNumElements() + T2->getNumElements(); ArrayType *NewType = ArrayType::get(T1->getElementType(), NewSize); // Create the new global variable... GlobalVariable *NG = new GlobalVariable(NewType, G1->isConstant(), G1->getLinkage(), /*init*/0, First->first, M); // Merge the initializer... Inits.reserve(NewSize); ConstantArray *I = cast(G1->getInitializer()); for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i) Inits.push_back(cast(I->getValues()[i])); I = cast(G2->getInitializer()); for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i) Inits.push_back(cast(I->getValues()[i])); 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! ConstantPointerRef *NGCP = ConstantPointerRef::get(NG); G1->replaceAllUsesWith(ConstantExpr::getCast(NGCP, G1->getType())); G2->replaceAllUsesWith(ConstantExpr::getCast(NGCP, 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; } // 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 LinkModules(Module *Dest, const Module *Src, std::string *ErrorMsg) { if (Dest->getEndianness() == Module::AnyEndianness) Dest->setEndianness(Src->getEndianness()); if (Dest->getPointerSize() == Module::AnyPointerSize) Dest->setPointerSize(Src->getPointerSize()); if (Src->getEndianness() != Module::AnyEndianness && Dest->getEndianness() != Src->getEndianness()) std::cerr << "WARNING: Linking two modules of different endianness!\n"; if (Src->getPointerSize() != Module::AnyPointerSize && Dest->getPointerSize() != Src->getPointerSize()) std::cerr << "WARNING: Linking two modules of different pointer size!\n"; // 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 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 AppendingVars; // Add all of the appending globals already in the Dest module to // AppendingVars. for (Module::giterator I = Dest->gbegin(), E = Dest->gend(); I != E; ++I) if (I->hasAppendingLinkage()) AppendingVars.insert(std::make_pair(I->getName(), I)); // 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; // 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; return false; }