//===- 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/Module.h" #include "llvm/TypeSymbolTable.h" #include "llvm/ValueSymbolTable.h" #include "llvm/Instructions.h" #include "llvm/Assembly/Writer.h" #include "llvm/Support/Streams.h" #include "llvm/System/Path.h" #include 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 std::string &Message) { if (E) *E = Message; return true; } // ToStr - Simple wrapper function to convert a type to a string. static std::string ToStr(const Type *Ty, const Module *M) { std::ostringstream OS; WriteTypeSymbolic(OS, Ty, M); return OS.str(); } // // 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. // Name - The name of the type. // // 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, TypeSymbolTable *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, TypeSymbolTable *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->getTypeID() != SrcTyT->getTypeID()) return true; // Otherwise, resolve the used type used by this derived type... switch (DestTyT->getTypeID()) { case Type::IntegerTyID: { if (cast(DestTyT)->getBitWidth() != cast(SrcTyT)->getBitWidth()) return true; return false; } case Type::FunctionTyID: { if (cast(DestTyT)->isVarArg() != cast(SrcTyT)->isVarArg() || cast(DestTyT)->getNumContainedTypes() != cast(SrcTyT)->getNumContainedTypes()) 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, TypeSymbolTable *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) { 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 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 (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 = SrcST->lookup(Name); Type *T2 = DestST->lookup(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(SrcST->lookup(Name)); PATypeHolder T2(DestST->lookup(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. if (DelayedTypesToResolve.size() == OldSize) { // Remove the symbol name from the destination. DelayedTypesToResolve.pop_back(); } } } return false; } static void PrintMap(const std::map &M) { for (std::map::const_iterator I = M.begin(), E =M.end(); I != E; ++I) { cerr << " Fr: " << (void*)I->first << " "; I->first->dump(); cerr << " To: " << (void*)I->second << " "; I->second->dump(); cerr << "\n"; } } // RemapOperand - Use ValueMap to convert constants from one module to another. static Value *RemapOperand(const Value *In, std::map &ValueMap) { std::map::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(In)) { if ((!isa(CPV->getType()) && !isa(CPV)) || isa(CPV) || isa(CPV)) return const_cast(CPV); // Simple constants stay identical. if (const ConstantArray *CPA = dyn_cast(CPV)) { std::vector Operands(CPA->getNumOperands()); for (unsigned i = 0, e = CPA->getNumOperands(); i != e; ++i) Operands[i] =cast(RemapOperand(CPA->getOperand(i), ValueMap)); Result = ConstantArray::get(cast(CPA->getType()), Operands); } else if (const ConstantStruct *CPS = dyn_cast(CPV)) { std::vector Operands(CPS->getNumOperands()); for (unsigned i = 0, e = CPS->getNumOperands(); i != e; ++i) Operands[i] =cast(RemapOperand(CPS->getOperand(i), ValueMap)); Result = ConstantStruct::get(cast(CPS->getType()), Operands); } else if (isa(CPV) || isa(CPV)) { Result = const_cast(CPV); } else if (const ConstantVector *CP = dyn_cast(CPV)) { std::vector Operands(CP->getNumOperands()); for (unsigned i = 0, e = CP->getNumOperands(); i != e; ++i) Operands[i] = cast(RemapOperand(CP->getOperand(i), ValueMap)); Result = ConstantVector::get(Operands); } else if (const ConstantExpr *CE = dyn_cast(CPV)) { std::vector Ops; for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) Ops.push_back(cast(RemapOperand(CE->getOperand(i),ValueMap))); Result = CE->getWithOperands(Ops); } else if (isa(CPV)) { assert(0 && "Unmapped global?"); } else { assert(0 && "Unknown type of derived type constant value!"); } } else if (isa(In)) { Result = const_cast(In); } // Cache the mapping in our local map structure if (Result) { ValueMap[In] = Result; return Result; } cerr << "LinkModules ValueMap: \n"; PrintMap(ValueMap); cerr << "Couldn't remap value: " << (void*)In << " " << *In << "\n"; assert(0 && "Couldn't remap value!"); 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(ST.lookup(Name))) { assert(ConflictGV->hasInternalLinkage() && "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) { // Propagate alignment, visibility and section info. DestGV->setAlignment(std::max(DestGV->getAlignment(), SrcGV->getAlignment())); DestGV->setSection(SrcGV->getSection()); DestGV->setVisibility(SrcGV->getVisibility()); if (const Function *SrcF = dyn_cast(SrcGV)) { Function *DestF = cast(DestGV); DestF->setCallingConv(SrcF->getCallingConv()); DestF->setParamAttrs(SrcF->getParamAttrs()); if (SrcF->hasCollector()) DestF->setCollector(SrcF->getCollector()); } else if (const GlobalVariable *SrcVar = dyn_cast(SrcGV)) { GlobalVariable *DestVar = cast(DestGV); DestVar->setThreadLocal(SrcVar->isThreadLocal()); } } /// 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->hasInternalLinkage()) && "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->hasWeakLinkage() || Src->hasLinkOnceLinkage()) { // At this point we know that Dest has LinkOnce, External*, Weak, or // DLL* linkage. if ((Dest->hasLinkOnceLinkage() && Src->hasWeakLinkage()) || Dest->hasExternalWeakLinkage()) { LinkFromSrc = true; LT = Src->getLinkage(); } else { LinkFromSrc = false; LT = Dest->getLinkage(); } } else if (Dest->hasWeakLinkage() || Dest->hasLinkOnceLinkage()) { // 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; } // 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) { // 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 if (SGV->hasName() && !SGV->hasInternalLinkage()) { DGV = Dest->getGlobalVariable(SGV->getName()); if (DGV && DGV->getType() != SGV->getType()) // If types don't agree due to opaque types, try to resolve them. RecursiveResolveTypes(SGV->getType(), DGV->getType(), &Dest->getTypeSymbolTable(), ""); } // Check to see if may have to link the global with the alias if (!DGV && SGV->hasName() && !SGV->hasInternalLinkage()) { DGV = Dest->getNamedAlias(SGV->getName()); if (DGV && DGV->getType() != SGV->getType()) // If types don't agree due to opaque types, try to resolve them. RecursiveResolveTypes(SGV->getType(), DGV->getType(), &Dest->getTypeSymbolTable(), ""); } if (DGV && DGV->hasInternalLinkage()) DGV = 0; 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) { // 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); // 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->getName() != SGV->getName() && !NewDGV->hasInternalLinkage()) ForceRenaming(NewDGV, SGV->getName()); // Make sure to remember this mapping... ValueMap[SGV] = NewDGV; if (SGV->hasAppendingLinkage()) // Keep track that this is an appending variable... AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV)); } else 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(SGV->getType()->getElementType(), SGV->isConstant(), SGV->getLinkage(), /*init*/0, "", Dest); // 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)); } else if (GlobalAlias *DGA = dyn_cast(DGV)) { // SGV is global, but DGV is alias. The only valid mapping is when SGV is // external declaration, which is effectively a no-op. Also make sure // linkage calculation was correct. if (SGV->isDeclaration() && !LinkFromSrc) { // Make sure to remember this mapping... ValueMap[SGV] = DGA; } else return Error(Err, "Global-Alias Collision on '" + SGV->getName() + "': symbol multiple defined"); } else if (GlobalVariable *DGVar = dyn_cast(DGV)) { // Otherwise, perform the global-global mapping as instructed by // GetLinkageResult. if (LinkFromSrc) { // Propagate alignment, section, and visibility info. CopyGVAttributes(DGVar, SGV); // 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. if (SGV->getType() != DGVar->getType()) { GlobalVariable *NewDGV = new GlobalVariable(SGV->getType()->getElementType(), DGVar->isConstant(), DGVar->getLinkage(), /*init*/0, DGVar->getName(), Dest); CopyGVAttributes(NewDGV, DGVar); DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDGV, DGVar->getType())); // DGVar 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. DGVar->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 it. if (NewDGV->getName() != SGV->getName() && !NewDGV->hasInternalLinkage()) ForceRenaming(NewDGV, SGV->getName()); DGVar = NewDGV; } // Inherit const as appropriate DGVar->setConstant(SGV->isConstant()); // Set initializer to zero, so we can link the stuff later DGVar->setInitializer(0); } else { // Special case for const propagation if (DGVar->isDeclaration() && SGV->isConstant() && !DGVar->isConstant()) DGVar->setConstant(true); } // Set calculated linkage DGVar->setLinkage(NewLinkage); // Make sure to remember this mapping... ValueMap[SGV] = ConstantExpr::getBitCast(DGVar, SGV->getType()); } } return false; } static GlobalValue::LinkageTypes CalculateAliasLinkage(const GlobalValue *SGV, const GlobalValue *DGV) { if (SGV->hasExternalLinkage() || DGV->hasExternalLinkage()) return GlobalValue::ExternalLinkage; else if (SGV->hasWeakLinkage() || DGV->hasWeakLinkage()) return GlobalValue::WeakLinkage; else { assert(SGV->hasInternalLinkage() && DGV->hasInternalLinkage() && "Unexpected linkage type"); return GlobalValue::InternalLinkage; } } // 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 &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_iterator VMI = ValueMap.find(SAliasee); assert(VMI != ValueMap.end() && "Aliasee not linked"); GlobalValue* DAliasee = cast(VMI->second); // Try to find something 'similar' to SGA in destination module. if (GlobalAlias *DGA = Dest->getNamedAlias(SGA->getName())) { // If types don't agree due to opaque types, try to resolve them. if (RecursiveResolveTypes(SGA->getType(), DGA->getType(), &Dest->getTypeSymbolTable(), "")) return Error(Err, "Alias Collision on '" + SGA->getName()+ "': aliases have different types"); // Now 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 *DGV = Dest->getGlobalVariable(SGA->getName())) { RecursiveResolveTypes(SGA->getType(), DGV->getType(), &Dest->getTypeSymbolTable(), ""); // The only allowed way is to link alias with external declaration. if (DGV->isDeclaration()) { 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() != DGV->getType()) DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewGA, DGV->getType())); else DGV->replaceAllUsesWith(NewGA); // DGV 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. DGV->eraseFromParent(); // Proceed to 'common' steps } else return Error(Err, "Global-Alias Collision on '" + SGA->getName() + "': symbol multiple defined"); } else if (Function *DF = Dest->getFunction(SGA->getName())) { RecursiveResolveTypes(SGA->getType(), DF->getType(), &Dest->getTypeSymbolTable(), ""); // The only allowed way is to link alias with external declaration. if (DF->isDeclaration()) { 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 { // Nothing similar found, just copy alias into destination module. NewGA = new GlobalAlias(SGA->getType(), SGA->getLinkage(), SGA->getName(), DAliasee, 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, DGV must be an global value with internal linkage. Rename it. if (NewGA->getName() != SGA->getName() && !NewGA->hasInternalLinkage()) 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 &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(RemapOperand(SGV->getInitializer(), ValueMap)); GlobalVariable *DGV = cast(ValueMap[SGV]); if (DGV->hasInitializer()) { if (SGV->hasExternalLinkage()) { if (DGV->getInitializer() != SInit) return Error(Err, "Global Variable Collision on '" + SGV->getName() + "': global variables have different initializers"); } else if (DGV->hasLinkOnceLinkage() || DGV->hasWeakLinkage()) { // Nothing is required, mapped values will take the new global // automatically. } else if (SGV->hasLinkOnceLinkage() || SGV->hasWeakLinkage()) { // 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) { // 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 Function *DF = 0; if (SF->hasName() && !SF->hasInternalLinkage()) { // Check to see if may have to link the function. DF = Dest->getFunction(SF->getName()); if (DF && SF->getType() != DF->getType()) // If types don't agree because of opaque, try to resolve them RecursiveResolveTypes(SF->getType(), DF->getType(), &Dest->getTypeSymbolTable(), ""); } // Check visibility if (DF && !DF->hasInternalLinkage() && SF->getVisibility() != DF->getVisibility()) { // If one is a prototype, ignore its visibility. Prototypes are always // overridden by the definition. if (!SF->isDeclaration() && !DF->isDeclaration()) return Error(Err, "Linking functions named '" + SF->getName() + "': symbols have different visibilities!"); } if (DF && DF->hasInternalLinkage()) DF = NULL; if (DF && DF->getType() != SF->getType()) { if (DF->isDeclaration() && !SF->isDeclaration()) { // 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 = new Function(SF->getFunctionType(), SF->getLinkage(), SF->getName(), Dest); CopyGVAttributes(NewDF, SF); // Any uses of DF need to change to NewDF, with cast DF->replaceAllUsesWith(ConstantExpr::getBitCast(NewDF, DF->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. DF->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->hasInternalLinkage()) ForceRenaming(NewDF, SF->getName()); // Remember this mapping so uses in the source module get remapped // later by RemapOperand. ValueMap[SF] = NewDF; } else if (SF->isDeclaration()) { // We have two functions of the same name but different type and the // source is a declaration while the destination is not. Any use of // the source must be mapped to the destination, with a cast. ValueMap[SF] = ConstantExpr::getBitCast(DF, SF->getType()); } else { // We have two functions of the same name but different types and they // are both definitions. This is an error. return Error(Err, "Function '" + DF->getName() + "' defined as both '" + ToStr(SF->getFunctionType(), Src) + "' and '" + ToStr(DF->getFunctionType(), Dest) + "'"); } } else 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); 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->getName() != SF->getName() && !NewDF->hasInternalLinkage()) ForceRenaming(NewDF, SF->getName()); // ... and remember this mapping... ValueMap[SF] = NewDF; } else if (SF->isDeclaration()) { // If SF is a declaration or if both SF & DF are declarations, just link // the declarations, we aren't adding anything. if (SF->hasDLLImportLinkage()) { if (DF->isDeclaration()) { ValueMap.insert(std::make_pair(SF, DF)); DF->setLinkage(SF->getLinkage()); } } else { ValueMap[SF] = DF; } } else if (DF->isDeclaration() && !DF->hasDLLImportLinkage()) { // 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()); // Visibility of prototype is overridden by vis of definition. DF->setVisibility(SF->getVisibility()); } else if (SF->hasWeakLinkage() || SF->hasLinkOnceLinkage()) { // At this point we know that DF has LinkOnce, Weak, or External* linkage. ValueMap[SF] = DF; // Linkonce+Weak = Weak // *+External Weak = * if ((DF->hasLinkOnceLinkage() && SF->hasWeakLinkage()) || DF->hasExternalWeakLinkage()) DF->setLinkage(SF->getLinkage()); } else if (DF->hasWeakLinkage() || DF->hasLinkOnceLinkage()) { // At this point we know that SF has LinkOnce or External* linkage. ValueMap[SF] = DF; if (!SF->hasLinkOnceLinkage() && !SF->hasExternalWeakLinkage()) // Don't inherit linkonce & external weak linkage 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 identically in both modules!! return Error(Err, "Function '" + ToStr(SF->getFunctionType(), Src) + "':\"" + SF->getName() + "\" - Function is already defined!"); } 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, Function *Src, std::map &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(*OI) && !isa(*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 &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 = cast(ValueMap[SF]); // Destination function // DF not external SF external? if (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 &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!"); 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(NewType, G1->isConstant(), G1->getLinkage(), /*init*/0, First->first, M, G1->isThreadLocal()); // Propagate alignment, visibility and section info. CopyGVAttributes(NG, G1); // Merge the initializer... Inits.reserve(NewSize); if (ConstantArray *I = dyn_cast(G1->getInitializer())) { for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i) Inits.push_back(I->getOperand(i)); } else { assert(isa(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(G2->getInitializer())) { for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i) Inits.push_back(I->getOperand(i)); } else { assert(isa(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) { GlobalValue* GV = const_cast(I->getAliasedGlobal()); if (!GV->isDeclaration()) I->replaceAllUsesWith(GV); } 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()) cerr << "WARNING: Linking two modules of different data layouts!\n"; if (!Src->getTargetTriple().empty() && Dest->getTargetTriple() != Src->getTargetTriple()) cerr << "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 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; 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 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