LinkModules.cpp revision 2a749d36475bda8964e996725ea101aec3ee15cf
1//===- lib/Linker/LinkModules.cpp - Module Linker Implementation ----------===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file implements the LLVM module linker. 11// 12// Specifically, this: 13// * Merges global variables between the two modules 14// * Uninit + Uninit = Init, Init + Uninit = Init, Init + Init = Error if != 15// * Merges functions between two modules 16// 17//===----------------------------------------------------------------------===// 18 19#include "llvm/Linker.h" 20#include "llvm/Constants.h" 21#include "llvm/DerivedTypes.h" 22#include "llvm/LLVMContext.h" 23#include "llvm/Module.h" 24#include "llvm/TypeSymbolTable.h" 25#include "llvm/ValueSymbolTable.h" 26#include "llvm/Instructions.h" 27#include "llvm/Assembly/Writer.h" 28#include "llvm/Support/ErrorHandling.h" 29#include "llvm/Support/raw_ostream.h" 30#include "llvm/System/Path.h" 31#include "llvm/ADT/DenseMap.h" 32using namespace llvm; 33 34// Error - Simple wrapper function to conditionally assign to E and return true. 35// This just makes error return conditions a little bit simpler... 36static inline bool Error(std::string *E, const Twine &Message) { 37 if (E) *E = Message.str(); 38 return true; 39} 40 41// Function: ResolveTypes() 42// 43// Description: 44// Attempt to link the two specified types together. 45// 46// Inputs: 47// DestTy - The type to which we wish to resolve. 48// SrcTy - The original type which we want to resolve. 49// 50// Outputs: 51// DestST - The symbol table in which the new type should be placed. 52// 53// Return value: 54// true - There is an error and the types cannot yet be linked. 55// false - No errors. 56// 57static bool ResolveTypes(const Type *DestTy, const Type *SrcTy) { 58 if (DestTy == SrcTy) return false; // If already equal, noop 59 assert(DestTy && SrcTy && "Can't handle null types"); 60 61 if (const OpaqueType *OT = dyn_cast<OpaqueType>(DestTy)) { 62 // Type _is_ in module, just opaque... 63 const_cast<OpaqueType*>(OT)->refineAbstractTypeTo(SrcTy); 64 } else if (const OpaqueType *OT = dyn_cast<OpaqueType>(SrcTy)) { 65 const_cast<OpaqueType*>(OT)->refineAbstractTypeTo(DestTy); 66 } else { 67 return true; // Cannot link types... not-equal and neither is opaque. 68 } 69 return false; 70} 71 72/// LinkerTypeMap - This implements a map of types that is stable 73/// even if types are resolved/refined to other types. This is not a general 74/// purpose map, it is specific to the linker's use. 75namespace { 76class LinkerTypeMap : public AbstractTypeUser { 77 typedef DenseMap<const Type*, PATypeHolder> TheMapTy; 78 TheMapTy TheMap; 79 80 LinkerTypeMap(const LinkerTypeMap&); // DO NOT IMPLEMENT 81 void operator=(const LinkerTypeMap&); // DO NOT IMPLEMENT 82public: 83 LinkerTypeMap() {} 84 ~LinkerTypeMap() { 85 for (DenseMap<const Type*, PATypeHolder>::iterator I = TheMap.begin(), 86 E = TheMap.end(); I != E; ++I) 87 I->first->removeAbstractTypeUser(this); 88 } 89 90 /// lookup - Return the value for the specified type or null if it doesn't 91 /// exist. 92 const Type *lookup(const Type *Ty) const { 93 TheMapTy::const_iterator I = TheMap.find(Ty); 94 if (I != TheMap.end()) return I->second; 95 return 0; 96 } 97 98 /// erase - Remove the specified type, returning true if it was in the set. 99 bool erase(const Type *Ty) { 100 if (!TheMap.erase(Ty)) 101 return false; 102 if (Ty->isAbstract()) 103 Ty->removeAbstractTypeUser(this); 104 return true; 105 } 106 107 /// insert - This returns true if the pointer was new to the set, false if it 108 /// was already in the set. 109 bool insert(const Type *Src, const Type *Dst) { 110 if (!TheMap.insert(std::make_pair(Src, PATypeHolder(Dst))).second) 111 return false; // Already in map. 112 if (Src->isAbstract()) 113 Src->addAbstractTypeUser(this); 114 return true; 115 } 116 117protected: 118 /// refineAbstractType - The callback method invoked when an abstract type is 119 /// resolved to another type. An object must override this method to update 120 /// its internal state to reference NewType instead of OldType. 121 /// 122 virtual void refineAbstractType(const DerivedType *OldTy, 123 const Type *NewTy) { 124 TheMapTy::iterator I = TheMap.find(OldTy); 125 const Type *DstTy = I->second; 126 127 TheMap.erase(I); 128 if (OldTy->isAbstract()) 129 OldTy->removeAbstractTypeUser(this); 130 131 // Don't reinsert into the map if the key is concrete now. 132 if (NewTy->isAbstract()) 133 insert(NewTy, DstTy); 134 } 135 136 /// The other case which AbstractTypeUsers must be aware of is when a type 137 /// makes the transition from being abstract (where it has clients on it's 138 /// AbstractTypeUsers list) to concrete (where it does not). This method 139 /// notifies ATU's when this occurs for a type. 140 virtual void typeBecameConcrete(const DerivedType *AbsTy) { 141 TheMap.erase(AbsTy); 142 AbsTy->removeAbstractTypeUser(this); 143 } 144 145 // for debugging... 146 virtual void dump() const { 147 errs() << "AbstractTypeSet!\n"; 148 } 149}; 150} 151 152 153// RecursiveResolveTypes - This is just like ResolveTypes, except that it 154// recurses down into derived types, merging the used types if the parent types 155// are compatible. 156static bool RecursiveResolveTypesI(const Type *DstTy, const Type *SrcTy, 157 LinkerTypeMap &Pointers) { 158 if (DstTy == SrcTy) return false; // If already equal, noop 159 160 // If we found our opaque type, resolve it now! 161 if (isa<OpaqueType>(DstTy) || isa<OpaqueType>(SrcTy)) 162 return ResolveTypes(DstTy, SrcTy); 163 164 // Two types cannot be resolved together if they are of different primitive 165 // type. For example, we cannot resolve an int to a float. 166 if (DstTy->getTypeID() != SrcTy->getTypeID()) return true; 167 168 // If neither type is abstract, then they really are just different types. 169 if (!DstTy->isAbstract() && !SrcTy->isAbstract()) 170 return true; 171 172 // Otherwise, resolve the used type used by this derived type... 173 switch (DstTy->getTypeID()) { 174 default: 175 return true; 176 case Type::FunctionTyID: { 177 const FunctionType *DstFT = cast<FunctionType>(DstTy); 178 const FunctionType *SrcFT = cast<FunctionType>(SrcTy); 179 if (DstFT->isVarArg() != SrcFT->isVarArg() || 180 DstFT->getNumContainedTypes() != SrcFT->getNumContainedTypes()) 181 return true; 182 183 // Use TypeHolder's so recursive resolution won't break us. 184 PATypeHolder ST(SrcFT), DT(DstFT); 185 for (unsigned i = 0, e = DstFT->getNumContainedTypes(); i != e; ++i) { 186 const Type *SE = ST->getContainedType(i), *DE = DT->getContainedType(i); 187 if (SE != DE && RecursiveResolveTypesI(DE, SE, Pointers)) 188 return true; 189 } 190 return false; 191 } 192 case Type::StructTyID: { 193 const StructType *DstST = cast<StructType>(DstTy); 194 const StructType *SrcST = cast<StructType>(SrcTy); 195 if (DstST->getNumContainedTypes() != SrcST->getNumContainedTypes()) 196 return true; 197 198 PATypeHolder ST(SrcST), DT(DstST); 199 for (unsigned i = 0, e = DstST->getNumContainedTypes(); i != e; ++i) { 200 const Type *SE = ST->getContainedType(i), *DE = DT->getContainedType(i); 201 if (SE != DE && RecursiveResolveTypesI(DE, SE, Pointers)) 202 return true; 203 } 204 return false; 205 } 206 case Type::ArrayTyID: { 207 const ArrayType *DAT = cast<ArrayType>(DstTy); 208 const ArrayType *SAT = cast<ArrayType>(SrcTy); 209 if (DAT->getNumElements() != SAT->getNumElements()) return true; 210 return RecursiveResolveTypesI(DAT->getElementType(), SAT->getElementType(), 211 Pointers); 212 } 213 case Type::VectorTyID: { 214 const VectorType *DVT = cast<VectorType>(DstTy); 215 const VectorType *SVT = cast<VectorType>(SrcTy); 216 if (DVT->getNumElements() != SVT->getNumElements()) return true; 217 return RecursiveResolveTypesI(DVT->getElementType(), SVT->getElementType(), 218 Pointers); 219 } 220 case Type::PointerTyID: { 221 const PointerType *DstPT = cast<PointerType>(DstTy); 222 const PointerType *SrcPT = cast<PointerType>(SrcTy); 223 224 if (DstPT->getAddressSpace() != SrcPT->getAddressSpace()) 225 return true; 226 227 // If this is a pointer type, check to see if we have already seen it. If 228 // so, we are in a recursive branch. Cut off the search now. We cannot use 229 // an associative container for this search, because the type pointers (keys 230 // in the container) change whenever types get resolved. 231 if (SrcPT->isAbstract()) 232 if (const Type *ExistingDestTy = Pointers.lookup(SrcPT)) 233 return ExistingDestTy != DstPT; 234 235 if (DstPT->isAbstract()) 236 if (const Type *ExistingSrcTy = Pointers.lookup(DstPT)) 237 return ExistingSrcTy != SrcPT; 238 // Otherwise, add the current pointers to the vector to stop recursion on 239 // this pair. 240 if (DstPT->isAbstract()) 241 Pointers.insert(DstPT, SrcPT); 242 if (SrcPT->isAbstract()) 243 Pointers.insert(SrcPT, DstPT); 244 245 return RecursiveResolveTypesI(DstPT->getElementType(), 246 SrcPT->getElementType(), Pointers); 247 } 248 } 249} 250 251static bool RecursiveResolveTypes(const Type *DestTy, const Type *SrcTy) { 252 LinkerTypeMap PointerTypes; 253 return RecursiveResolveTypesI(DestTy, SrcTy, PointerTypes); 254} 255 256 257// LinkTypes - Go through the symbol table of the Src module and see if any 258// types are named in the src module that are not named in the Dst module. 259// Make sure there are no type name conflicts. 260static bool LinkTypes(Module *Dest, const Module *Src, std::string *Err) { 261 TypeSymbolTable *DestST = &Dest->getTypeSymbolTable(); 262 const TypeSymbolTable *SrcST = &Src->getTypeSymbolTable(); 263 264 // Look for a type plane for Type's... 265 TypeSymbolTable::const_iterator TI = SrcST->begin(); 266 TypeSymbolTable::const_iterator TE = SrcST->end(); 267 if (TI == TE) return false; // No named types, do nothing. 268 269 // Some types cannot be resolved immediately because they depend on other 270 // types being resolved to each other first. This contains a list of types we 271 // are waiting to recheck. 272 std::vector<std::string> DelayedTypesToResolve; 273 274 for ( ; TI != TE; ++TI ) { 275 const std::string &Name = TI->first; 276 const Type *RHS = TI->second; 277 278 // Check to see if this type name is already in the dest module. 279 Type *Entry = DestST->lookup(Name); 280 281 // If the name is just in the source module, bring it over to the dest. 282 if (Entry == 0) { 283 if (!Name.empty()) 284 DestST->insert(Name, const_cast<Type*>(RHS)); 285 } else if (ResolveTypes(Entry, RHS)) { 286 // They look different, save the types 'till later to resolve. 287 DelayedTypesToResolve.push_back(Name); 288 } 289 } 290 291 // Iteratively resolve types while we can... 292 while (!DelayedTypesToResolve.empty()) { 293 // Loop over all of the types, attempting to resolve them if possible... 294 unsigned OldSize = DelayedTypesToResolve.size(); 295 296 // Try direct resolution by name... 297 for (unsigned i = 0; i != DelayedTypesToResolve.size(); ++i) { 298 const std::string &Name = DelayedTypesToResolve[i]; 299 Type *T1 = SrcST->lookup(Name); 300 Type *T2 = DestST->lookup(Name); 301 if (!ResolveTypes(T2, T1)) { 302 // We are making progress! 303 DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i); 304 --i; 305 } 306 } 307 308 // Did we not eliminate any types? 309 if (DelayedTypesToResolve.size() == OldSize) { 310 // Attempt to resolve subelements of types. This allows us to merge these 311 // two types: { int* } and { opaque* } 312 for (unsigned i = 0, e = DelayedTypesToResolve.size(); i != e; ++i) { 313 const std::string &Name = DelayedTypesToResolve[i]; 314 if (!RecursiveResolveTypes(SrcST->lookup(Name), DestST->lookup(Name))) { 315 // We are making progress! 316 DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i); 317 318 // Go back to the main loop, perhaps we can resolve directly by name 319 // now... 320 break; 321 } 322 } 323 324 // If we STILL cannot resolve the types, then there is something wrong. 325 if (DelayedTypesToResolve.size() == OldSize) { 326 // Remove the symbol name from the destination. 327 DelayedTypesToResolve.pop_back(); 328 } 329 } 330 } 331 332 333 return false; 334} 335 336#ifndef NDEBUG 337static void PrintMap(const std::map<const Value*, Value*> &M) { 338 for (std::map<const Value*, Value*>::const_iterator I = M.begin(), E =M.end(); 339 I != E; ++I) { 340 errs() << " Fr: " << (void*)I->first << " "; 341 I->first->dump(); 342 errs() << " To: " << (void*)I->second << " "; 343 I->second->dump(); 344 errs() << "\n"; 345 } 346} 347#endif 348 349 350// RemapOperand - Use ValueMap to convert constants from one module to another. 351static Value *RemapOperand(const Value *In, 352 std::map<const Value*, Value*> &ValueMap) { 353 std::map<const Value*,Value*>::const_iterator I = ValueMap.find(In); 354 if (I != ValueMap.end()) 355 return I->second; 356 357 // Check to see if it's a constant that we are interested in transforming. 358 Value *Result = 0; 359 if (const Constant *CPV = dyn_cast<Constant>(In)) { 360 if ((!isa<DerivedType>(CPV->getType()) && !isa<ConstantExpr>(CPV)) || 361 isa<ConstantInt>(CPV) || isa<ConstantAggregateZero>(CPV)) 362 return const_cast<Constant*>(CPV); // Simple constants stay identical. 363 364 if (const ConstantArray *CPA = dyn_cast<ConstantArray>(CPV)) { 365 std::vector<Constant*> Operands(CPA->getNumOperands()); 366 for (unsigned i = 0, e = CPA->getNumOperands(); i != e; ++i) 367 Operands[i] =cast<Constant>(RemapOperand(CPA->getOperand(i), ValueMap)); 368 Result = ConstantArray::get(cast<ArrayType>(CPA->getType()), Operands); 369 } else if (const ConstantStruct *CPS = dyn_cast<ConstantStruct>(CPV)) { 370 std::vector<Constant*> Operands(CPS->getNumOperands()); 371 for (unsigned i = 0, e = CPS->getNumOperands(); i != e; ++i) 372 Operands[i] =cast<Constant>(RemapOperand(CPS->getOperand(i), ValueMap)); 373 Result = ConstantStruct::get(cast<StructType>(CPS->getType()), Operands); 374 } else if (isa<ConstantPointerNull>(CPV) || isa<UndefValue>(CPV)) { 375 Result = const_cast<Constant*>(CPV); 376 } else if (const ConstantVector *CP = dyn_cast<ConstantVector>(CPV)) { 377 std::vector<Constant*> Operands(CP->getNumOperands()); 378 for (unsigned i = 0, e = CP->getNumOperands(); i != e; ++i) 379 Operands[i] = cast<Constant>(RemapOperand(CP->getOperand(i), ValueMap)); 380 Result = ConstantVector::get(Operands); 381 } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CPV)) { 382 std::vector<Constant*> Ops; 383 for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) 384 Ops.push_back(cast<Constant>(RemapOperand(CE->getOperand(i),ValueMap))); 385 Result = CE->getWithOperands(Ops); 386 } else if (const BlockAddress *CE = dyn_cast<BlockAddress>(CPV)) { 387 Result = BlockAddress::get( 388 cast<Function>(RemapOperand(CE->getFunction(), ValueMap)), 389 CE->getBasicBlock()); 390 } else { 391 assert(!isa<GlobalValue>(CPV) && "Unmapped global?"); 392 llvm_unreachable("Unknown type of derived type constant value!"); 393 } 394 } else if (isa<MetadataBase>(In)) { 395 Result = const_cast<Value*>(In); 396 } else if (isa<InlineAsm>(In)) { 397 Result = const_cast<Value*>(In); 398 } 399 400 // Cache the mapping in our local map structure 401 if (Result) { 402 ValueMap[In] = Result; 403 return Result; 404 } 405 406#ifndef NDEBUG 407 errs() << "LinkModules ValueMap: \n"; 408 PrintMap(ValueMap); 409 410 errs() << "Couldn't remap value: " << (void*)In << " " << *In << "\n"; 411 llvm_unreachable("Couldn't remap value!"); 412#endif 413 return 0; 414} 415 416/// ForceRenaming - The LLVM SymbolTable class autorenames globals that conflict 417/// in the symbol table. This is good for all clients except for us. Go 418/// through the trouble to force this back. 419static void ForceRenaming(GlobalValue *GV, const std::string &Name) { 420 assert(GV->getName() != Name && "Can't force rename to self"); 421 ValueSymbolTable &ST = GV->getParent()->getValueSymbolTable(); 422 423 // If there is a conflict, rename the conflict. 424 if (GlobalValue *ConflictGV = cast_or_null<GlobalValue>(ST.lookup(Name))) { 425 assert(ConflictGV->hasLocalLinkage() && 426 "Not conflicting with a static global, should link instead!"); 427 GV->takeName(ConflictGV); 428 ConflictGV->setName(Name); // This will cause ConflictGV to get renamed 429 assert(ConflictGV->getName() != Name && "ForceRenaming didn't work"); 430 } else { 431 GV->setName(Name); // Force the name back 432 } 433} 434 435/// CopyGVAttributes - copy additional attributes (those not needed to construct 436/// a GlobalValue) from the SrcGV to the DestGV. 437static void CopyGVAttributes(GlobalValue *DestGV, const GlobalValue *SrcGV) { 438 // Use the maximum alignment, rather than just copying the alignment of SrcGV. 439 unsigned Alignment = std::max(DestGV->getAlignment(), SrcGV->getAlignment()); 440 DestGV->copyAttributesFrom(SrcGV); 441 DestGV->setAlignment(Alignment); 442} 443 444/// GetLinkageResult - This analyzes the two global values and determines what 445/// the result will look like in the destination module. In particular, it 446/// computes the resultant linkage type, computes whether the global in the 447/// source should be copied over to the destination (replacing the existing 448/// one), and computes whether this linkage is an error or not. It also performs 449/// visibility checks: we cannot link together two symbols with different 450/// visibilities. 451static bool GetLinkageResult(GlobalValue *Dest, const GlobalValue *Src, 452 GlobalValue::LinkageTypes <, bool &LinkFromSrc, 453 std::string *Err) { 454 assert((!Dest || !Src->hasLocalLinkage()) && 455 "If Src has internal linkage, Dest shouldn't be set!"); 456 if (!Dest) { 457 // Linking something to nothing. 458 LinkFromSrc = true; 459 LT = Src->getLinkage(); 460 } else if (Src->isDeclaration()) { 461 // If Src is external or if both Src & Dest are external.. Just link the 462 // external globals, we aren't adding anything. 463 if (Src->hasDLLImportLinkage()) { 464 // If one of GVs has DLLImport linkage, result should be dllimport'ed. 465 if (Dest->isDeclaration()) { 466 LinkFromSrc = true; 467 LT = Src->getLinkage(); 468 } 469 } else if (Dest->hasExternalWeakLinkage()) { 470 // If the Dest is weak, use the source linkage. 471 LinkFromSrc = true; 472 LT = Src->getLinkage(); 473 } else { 474 LinkFromSrc = false; 475 LT = Dest->getLinkage(); 476 } 477 } else if (Dest->isDeclaration() && !Dest->hasDLLImportLinkage()) { 478 // If Dest is external but Src is not: 479 LinkFromSrc = true; 480 LT = Src->getLinkage(); 481 } else if (Src->hasAppendingLinkage() || Dest->hasAppendingLinkage()) { 482 if (Src->getLinkage() != Dest->getLinkage()) 483 return Error(Err, "Linking globals named '" + Src->getName() + 484 "': can only link appending global with another appending global!"); 485 LinkFromSrc = true; // Special cased. 486 LT = Src->getLinkage(); 487 } else if (Src->isWeakForLinker()) { 488 // At this point we know that Dest has LinkOnce, External*, Weak, Common, 489 // or DLL* linkage. 490 if (Dest->hasExternalWeakLinkage() || 491 Dest->hasAvailableExternallyLinkage() || 492 (Dest->hasLinkOnceLinkage() && 493 (Src->hasWeakLinkage() || Src->hasCommonLinkage()))) { 494 LinkFromSrc = true; 495 LT = Src->getLinkage(); 496 } else { 497 LinkFromSrc = false; 498 LT = Dest->getLinkage(); 499 } 500 } else if (Dest->isWeakForLinker()) { 501 // At this point we know that Src has External* or DLL* linkage. 502 if (Src->hasExternalWeakLinkage()) { 503 LinkFromSrc = false; 504 LT = Dest->getLinkage(); 505 } else { 506 LinkFromSrc = true; 507 LT = GlobalValue::ExternalLinkage; 508 } 509 } else { 510 assert((Dest->hasExternalLinkage() || 511 Dest->hasDLLImportLinkage() || 512 Dest->hasDLLExportLinkage() || 513 Dest->hasExternalWeakLinkage()) && 514 (Src->hasExternalLinkage() || 515 Src->hasDLLImportLinkage() || 516 Src->hasDLLExportLinkage() || 517 Src->hasExternalWeakLinkage()) && 518 "Unexpected linkage type!"); 519 return Error(Err, "Linking globals named '" + Src->getName() + 520 "': symbol multiply defined!"); 521 } 522 523 // Check visibility 524 if (Dest && Src->getVisibility() != Dest->getVisibility()) 525 if (!Src->isDeclaration() && !Dest->isDeclaration()) 526 return Error(Err, "Linking globals named '" + Src->getName() + 527 "': symbols have different visibilities!"); 528 return false; 529} 530 531// Insert all of the named mdnoes in Src into the Dest module. 532static void LinkNamedMDNodes(Module *Dest, Module *Src) { 533 for (Module::const_named_metadata_iterator I = Src->named_metadata_begin(), 534 E = Src->named_metadata_end(); I != E; ++I) { 535 const NamedMDNode *SrcNMD = I; 536 NamedMDNode *DestNMD = Dest->getNamedMetadata(SrcNMD->getName()); 537 if (!DestNMD) 538 NamedMDNode::Create(SrcNMD, Dest); 539 else { 540 // Add Src elements into Dest node. 541 for (unsigned i = 0, e = SrcNMD->getNumElements(); i != e; ++i) 542 DestNMD->addElement(SrcNMD->getElement(i)); 543 } 544 } 545} 546 547// LinkGlobals - Loop through the global variables in the src module and merge 548// them into the dest module. 549static bool LinkGlobals(Module *Dest, const Module *Src, 550 std::map<const Value*, Value*> &ValueMap, 551 std::multimap<std::string, GlobalVariable *> &AppendingVars, 552 std::string *Err) { 553 ValueSymbolTable &DestSymTab = Dest->getValueSymbolTable(); 554 555 // Loop over all of the globals in the src module, mapping them over as we go 556 for (Module::const_global_iterator I = Src->global_begin(), 557 E = Src->global_end(); I != E; ++I) { 558 const GlobalVariable *SGV = I; 559 GlobalValue *DGV = 0; 560 561 // Check to see if may have to link the global with the global, alias or 562 // function. 563 if (SGV->hasName() && !SGV->hasLocalLinkage()) 564 DGV = cast_or_null<GlobalValue>(DestSymTab.lookup(SGV->getName())); 565 566 // If we found a global with the same name in the dest module, but it has 567 // internal linkage, we are really not doing any linkage here. 568 if (DGV && DGV->hasLocalLinkage()) 569 DGV = 0; 570 571 // If types don't agree due to opaque types, try to resolve them. 572 if (DGV && DGV->getType() != SGV->getType()) 573 RecursiveResolveTypes(SGV->getType(), DGV->getType()); 574 575 assert((SGV->hasInitializer() || SGV->hasExternalWeakLinkage() || 576 SGV->hasExternalLinkage() || SGV->hasDLLImportLinkage()) && 577 "Global must either be external or have an initializer!"); 578 579 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; 580 bool LinkFromSrc = false; 581 if (GetLinkageResult(DGV, SGV, NewLinkage, LinkFromSrc, Err)) 582 return true; 583 584 if (DGV == 0) { 585 // No linking to be performed, simply create an identical version of the 586 // symbol over in the dest module... the initializer will be filled in 587 // later by LinkGlobalInits. 588 GlobalVariable *NewDGV = 589 new GlobalVariable(*Dest, SGV->getType()->getElementType(), 590 SGV->isConstant(), SGV->getLinkage(), /*init*/0, 591 SGV->getName(), 0, false, 592 SGV->getType()->getAddressSpace()); 593 // Propagate alignment, visibility and section info. 594 CopyGVAttributes(NewDGV, SGV); 595 596 // If the LLVM runtime renamed the global, but it is an externally visible 597 // symbol, DGV must be an existing global with internal linkage. Rename 598 // it. 599 if (!NewDGV->hasLocalLinkage() && NewDGV->getName() != SGV->getName()) 600 ForceRenaming(NewDGV, SGV->getName()); 601 602 // Make sure to remember this mapping. 603 ValueMap[SGV] = NewDGV; 604 605 // Keep track that this is an appending variable. 606 if (SGV->hasAppendingLinkage()) 607 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV)); 608 continue; 609 } 610 611 // If the visibilities of the symbols disagree and the destination is a 612 // prototype, take the visibility of its input. 613 if (DGV->isDeclaration()) 614 DGV->setVisibility(SGV->getVisibility()); 615 616 if (DGV->hasAppendingLinkage()) { 617 // No linking is performed yet. Just insert a new copy of the global, and 618 // keep track of the fact that it is an appending variable in the 619 // AppendingVars map. The name is cleared out so that no linkage is 620 // performed. 621 GlobalVariable *NewDGV = 622 new GlobalVariable(*Dest, SGV->getType()->getElementType(), 623 SGV->isConstant(), SGV->getLinkage(), /*init*/0, 624 "", 0, false, 625 SGV->getType()->getAddressSpace()); 626 627 // Set alignment allowing CopyGVAttributes merge it with alignment of SGV. 628 NewDGV->setAlignment(DGV->getAlignment()); 629 // Propagate alignment, section and visibility info. 630 CopyGVAttributes(NewDGV, SGV); 631 632 // Make sure to remember this mapping... 633 ValueMap[SGV] = NewDGV; 634 635 // Keep track that this is an appending variable... 636 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV)); 637 continue; 638 } 639 640 if (LinkFromSrc) { 641 if (isa<GlobalAlias>(DGV)) 642 return Error(Err, "Global-Alias Collision on '" + SGV->getName() + 643 "': symbol multiple defined"); 644 645 // If the types don't match, and if we are to link from the source, nuke 646 // DGV and create a new one of the appropriate type. Note that the thing 647 // we are replacing may be a function (if a prototype, weak, etc) or a 648 // global variable. 649 GlobalVariable *NewDGV = 650 new GlobalVariable(*Dest, SGV->getType()->getElementType(), 651 SGV->isConstant(), NewLinkage, /*init*/0, 652 DGV->getName(), 0, false, 653 SGV->getType()->getAddressSpace()); 654 655 // Propagate alignment, section, and visibility info. 656 CopyGVAttributes(NewDGV, SGV); 657 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDGV, 658 DGV->getType())); 659 660 // DGV will conflict with NewDGV because they both had the same 661 // name. We must erase this now so ForceRenaming doesn't assert 662 // because DGV might not have internal linkage. 663 if (GlobalVariable *Var = dyn_cast<GlobalVariable>(DGV)) 664 Var->eraseFromParent(); 665 else 666 cast<Function>(DGV)->eraseFromParent(); 667 DGV = NewDGV; 668 669 // If the symbol table renamed the global, but it is an externally visible 670 // symbol, DGV must be an existing global with internal linkage. Rename. 671 if (NewDGV->getName() != SGV->getName() && !NewDGV->hasLocalLinkage()) 672 ForceRenaming(NewDGV, SGV->getName()); 673 674 // Inherit const as appropriate. 675 NewDGV->setConstant(SGV->isConstant()); 676 677 // Make sure to remember this mapping. 678 ValueMap[SGV] = NewDGV; 679 continue; 680 } 681 682 // Not "link from source", keep the one in the DestModule and remap the 683 // input onto it. 684 685 // Special case for const propagation. 686 if (GlobalVariable *DGVar = dyn_cast<GlobalVariable>(DGV)) 687 if (DGVar->isDeclaration() && SGV->isConstant() && !DGVar->isConstant()) 688 DGVar->setConstant(true); 689 690 // SGV is global, but DGV is alias. 691 if (isa<GlobalAlias>(DGV)) { 692 // The only valid mappings are: 693 // - SGV is external declaration, which is effectively a no-op. 694 // - SGV is weak, when we just need to throw SGV out. 695 if (!SGV->isDeclaration() && !SGV->isWeakForLinker()) 696 return Error(Err, "Global-Alias Collision on '" + SGV->getName() + 697 "': symbol multiple defined"); 698 } 699 700 // Set calculated linkage 701 DGV->setLinkage(NewLinkage); 702 703 // Make sure to remember this mapping... 704 ValueMap[SGV] = ConstantExpr::getBitCast(DGV, SGV->getType()); 705 } 706 return false; 707} 708 709static GlobalValue::LinkageTypes 710CalculateAliasLinkage(const GlobalValue *SGV, const GlobalValue *DGV) { 711 GlobalValue::LinkageTypes SL = SGV->getLinkage(); 712 GlobalValue::LinkageTypes DL = DGV->getLinkage(); 713 if (SL == GlobalValue::ExternalLinkage || DL == GlobalValue::ExternalLinkage) 714 return GlobalValue::ExternalLinkage; 715 else if (SL == GlobalValue::WeakAnyLinkage || 716 DL == GlobalValue::WeakAnyLinkage) 717 return GlobalValue::WeakAnyLinkage; 718 else if (SL == GlobalValue::WeakODRLinkage || 719 DL == GlobalValue::WeakODRLinkage) 720 return GlobalValue::WeakODRLinkage; 721 else if (SL == GlobalValue::InternalLinkage && 722 DL == GlobalValue::InternalLinkage) 723 return GlobalValue::InternalLinkage; 724 else if (SL == GlobalValue::LinkerPrivateLinkage && 725 DL == GlobalValue::LinkerPrivateLinkage) 726 return GlobalValue::LinkerPrivateLinkage; 727 else { 728 assert (SL == GlobalValue::PrivateLinkage && 729 DL == GlobalValue::PrivateLinkage && "Unexpected linkage type"); 730 return GlobalValue::PrivateLinkage; 731 } 732} 733 734// LinkAlias - Loop through the alias in the src module and link them into the 735// dest module. We're assuming, that all functions/global variables were already 736// linked in. 737static bool LinkAlias(Module *Dest, const Module *Src, 738 std::map<const Value*, Value*> &ValueMap, 739 std::string *Err) { 740 // Loop over all alias in the src module 741 for (Module::const_alias_iterator I = Src->alias_begin(), 742 E = Src->alias_end(); I != E; ++I) { 743 const GlobalAlias *SGA = I; 744 const GlobalValue *SAliasee = SGA->getAliasedGlobal(); 745 GlobalAlias *NewGA = NULL; 746 747 // Globals were already linked, thus we can just query ValueMap for variant 748 // of SAliasee in Dest. 749 std::map<const Value*,Value*>::const_iterator VMI = ValueMap.find(SAliasee); 750 assert(VMI != ValueMap.end() && "Aliasee not linked"); 751 GlobalValue* DAliasee = cast<GlobalValue>(VMI->second); 752 GlobalValue* DGV = NULL; 753 754 // Try to find something 'similar' to SGA in destination module. 755 if (!DGV && !SGA->hasLocalLinkage()) { 756 DGV = Dest->getNamedAlias(SGA->getName()); 757 758 // If types don't agree due to opaque types, try to resolve them. 759 if (DGV && DGV->getType() != SGA->getType()) 760 RecursiveResolveTypes(SGA->getType(), DGV->getType()); 761 } 762 763 if (!DGV && !SGA->hasLocalLinkage()) { 764 DGV = Dest->getGlobalVariable(SGA->getName()); 765 766 // If types don't agree due to opaque types, try to resolve them. 767 if (DGV && DGV->getType() != SGA->getType()) 768 RecursiveResolveTypes(SGA->getType(), DGV->getType()); 769 } 770 771 if (!DGV && !SGA->hasLocalLinkage()) { 772 DGV = Dest->getFunction(SGA->getName()); 773 774 // If types don't agree due to opaque types, try to resolve them. 775 if (DGV && DGV->getType() != SGA->getType()) 776 RecursiveResolveTypes(SGA->getType(), DGV->getType()); 777 } 778 779 // No linking to be performed on internal stuff. 780 if (DGV && DGV->hasLocalLinkage()) 781 DGV = NULL; 782 783 if (GlobalAlias *DGA = dyn_cast_or_null<GlobalAlias>(DGV)) { 784 // Types are known to be the same, check whether aliasees equal. As 785 // globals are already linked we just need query ValueMap to find the 786 // mapping. 787 if (DAliasee == DGA->getAliasedGlobal()) { 788 // This is just two copies of the same alias. Propagate linkage, if 789 // necessary. 790 DGA->setLinkage(CalculateAliasLinkage(SGA, DGA)); 791 792 NewGA = DGA; 793 // Proceed to 'common' steps 794 } else 795 return Error(Err, "Alias Collision on '" + SGA->getName()+ 796 "': aliases have different aliasees"); 797 } else if (GlobalVariable *DGVar = dyn_cast_or_null<GlobalVariable>(DGV)) { 798 // The only allowed way is to link alias with external declaration or weak 799 // symbol.. 800 if (DGVar->isDeclaration() || DGVar->isWeakForLinker()) { 801 // But only if aliasee is global too... 802 if (!isa<GlobalVariable>(DAliasee)) 803 return Error(Err, "Global-Alias Collision on '" + SGA->getName() + 804 "': aliasee is not global variable"); 805 806 NewGA = new GlobalAlias(SGA->getType(), SGA->getLinkage(), 807 SGA->getName(), DAliasee, Dest); 808 CopyGVAttributes(NewGA, SGA); 809 810 // Any uses of DGV need to change to NewGA, with cast, if needed. 811 if (SGA->getType() != DGVar->getType()) 812 DGVar->replaceAllUsesWith(ConstantExpr::getBitCast(NewGA, 813 DGVar->getType())); 814 else 815 DGVar->replaceAllUsesWith(NewGA); 816 817 // DGVar will conflict with NewGA because they both had the same 818 // name. We must erase this now so ForceRenaming doesn't assert 819 // because DGV might not have internal linkage. 820 DGVar->eraseFromParent(); 821 822 // Proceed to 'common' steps 823 } else 824 return Error(Err, "Global-Alias Collision on '" + SGA->getName() + 825 "': symbol multiple defined"); 826 } else if (Function *DF = dyn_cast_or_null<Function>(DGV)) { 827 // The only allowed way is to link alias with external declaration or weak 828 // symbol... 829 if (DF->isDeclaration() || DF->isWeakForLinker()) { 830 // But only if aliasee is function too... 831 if (!isa<Function>(DAliasee)) 832 return Error(Err, "Function-Alias Collision on '" + SGA->getName() + 833 "': aliasee is not function"); 834 835 NewGA = new GlobalAlias(SGA->getType(), SGA->getLinkage(), 836 SGA->getName(), DAliasee, Dest); 837 CopyGVAttributes(NewGA, SGA); 838 839 // Any uses of DF need to change to NewGA, with cast, if needed. 840 if (SGA->getType() != DF->getType()) 841 DF->replaceAllUsesWith(ConstantExpr::getBitCast(NewGA, 842 DF->getType())); 843 else 844 DF->replaceAllUsesWith(NewGA); 845 846 // DF will conflict with NewGA because they both had the same 847 // name. We must erase this now so ForceRenaming doesn't assert 848 // because DF might not have internal linkage. 849 DF->eraseFromParent(); 850 851 // Proceed to 'common' steps 852 } else 853 return Error(Err, "Function-Alias Collision on '" + SGA->getName() + 854 "': symbol multiple defined"); 855 } else { 856 // No linking to be performed, simply create an identical version of the 857 // alias over in the dest module... 858 859 NewGA = new GlobalAlias(SGA->getType(), SGA->getLinkage(), 860 SGA->getName(), DAliasee, Dest); 861 CopyGVAttributes(NewGA, SGA); 862 863 // Proceed to 'common' steps 864 } 865 866 assert(NewGA && "No alias was created in destination module!"); 867 868 // If the symbol table renamed the alias, but it is an externally visible 869 // symbol, DGA must be an global value with internal linkage. Rename it. 870 if (NewGA->getName() != SGA->getName() && 871 !NewGA->hasLocalLinkage()) 872 ForceRenaming(NewGA, SGA->getName()); 873 874 // Remember this mapping so uses in the source module get remapped 875 // later by RemapOperand. 876 ValueMap[SGA] = NewGA; 877 } 878 879 return false; 880} 881 882 883// LinkGlobalInits - Update the initializers in the Dest module now that all 884// globals that may be referenced are in Dest. 885static bool LinkGlobalInits(Module *Dest, const Module *Src, 886 std::map<const Value*, Value*> &ValueMap, 887 std::string *Err) { 888 // Loop over all of the globals in the src module, mapping them over as we go 889 for (Module::const_global_iterator I = Src->global_begin(), 890 E = Src->global_end(); I != E; ++I) { 891 const GlobalVariable *SGV = I; 892 893 if (SGV->hasInitializer()) { // Only process initialized GV's 894 // Figure out what the initializer looks like in the dest module... 895 Constant *SInit = 896 cast<Constant>(RemapOperand(SGV->getInitializer(), ValueMap)); 897 // Grab destination global variable or alias. 898 GlobalValue *DGV = cast<GlobalValue>(ValueMap[SGV]->stripPointerCasts()); 899 900 // If dest if global variable, check that initializers match. 901 if (GlobalVariable *DGVar = dyn_cast<GlobalVariable>(DGV)) { 902 if (DGVar->hasInitializer()) { 903 if (SGV->hasExternalLinkage()) { 904 if (DGVar->getInitializer() != SInit) 905 return Error(Err, "Global Variable Collision on '" + 906 SGV->getName() + 907 "': global variables have different initializers"); 908 } else if (DGVar->isWeakForLinker()) { 909 // Nothing is required, mapped values will take the new global 910 // automatically. 911 } else if (SGV->isWeakForLinker()) { 912 // Nothing is required, mapped values will take the new global 913 // automatically. 914 } else if (DGVar->hasAppendingLinkage()) { 915 llvm_unreachable("Appending linkage unimplemented!"); 916 } else { 917 llvm_unreachable("Unknown linkage!"); 918 } 919 } else { 920 // Copy the initializer over now... 921 DGVar->setInitializer(SInit); 922 } 923 } else { 924 // Destination is alias, the only valid situation is when source is 925 // weak. Also, note, that we already checked linkage in LinkGlobals(), 926 // thus we assert here. 927 // FIXME: Should we weaken this assumption, 'dereference' alias and 928 // check for initializer of aliasee? 929 assert(SGV->isWeakForLinker()); 930 } 931 } 932 } 933 return false; 934} 935 936// LinkFunctionProtos - Link the functions together between the two modules, 937// without doing function bodies... this just adds external function prototypes 938// to the Dest function... 939// 940static bool LinkFunctionProtos(Module *Dest, const Module *Src, 941 std::map<const Value*, Value*> &ValueMap, 942 std::string *Err) { 943 ValueSymbolTable &DestSymTab = Dest->getValueSymbolTable(); 944 945 // Loop over all of the functions in the src module, mapping them over 946 for (Module::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) { 947 const Function *SF = I; // SrcFunction 948 GlobalValue *DGV = 0; 949 950 // Check to see if may have to link the function with the global, alias or 951 // function. 952 if (SF->hasName() && !SF->hasLocalLinkage()) 953 DGV = cast_or_null<GlobalValue>(DestSymTab.lookup(SF->getName())); 954 955 // If we found a global with the same name in the dest module, but it has 956 // internal linkage, we are really not doing any linkage here. 957 if (DGV && DGV->hasLocalLinkage()) 958 DGV = 0; 959 960 // If types don't agree due to opaque types, try to resolve them. 961 if (DGV && DGV->getType() != SF->getType()) 962 RecursiveResolveTypes(SF->getType(), DGV->getType()); 963 964 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; 965 bool LinkFromSrc = false; 966 if (GetLinkageResult(DGV, SF, NewLinkage, LinkFromSrc, Err)) 967 return true; 968 969 // If there is no linkage to be performed, just bring over SF without 970 // modifying it. 971 if (DGV == 0) { 972 // Function does not already exist, simply insert an function signature 973 // identical to SF into the dest module. 974 Function *NewDF = Function::Create(SF->getFunctionType(), 975 SF->getLinkage(), 976 SF->getName(), Dest); 977 CopyGVAttributes(NewDF, SF); 978 979 // If the LLVM runtime renamed the function, but it is an externally 980 // visible symbol, DF must be an existing function with internal linkage. 981 // Rename it. 982 if (!NewDF->hasLocalLinkage() && NewDF->getName() != SF->getName()) 983 ForceRenaming(NewDF, SF->getName()); 984 985 // ... and remember this mapping... 986 ValueMap[SF] = NewDF; 987 continue; 988 } 989 990 // If the visibilities of the symbols disagree and the destination is a 991 // prototype, take the visibility of its input. 992 if (DGV->isDeclaration()) 993 DGV->setVisibility(SF->getVisibility()); 994 995 if (LinkFromSrc) { 996 if (isa<GlobalAlias>(DGV)) 997 return Error(Err, "Function-Alias Collision on '" + SF->getName() + 998 "': symbol multiple defined"); 999 1000 // We have a definition of the same name but different type in the 1001 // source module. Copy the prototype to the destination and replace 1002 // uses of the destination's prototype with the new prototype. 1003 Function *NewDF = Function::Create(SF->getFunctionType(), NewLinkage, 1004 SF->getName(), Dest); 1005 CopyGVAttributes(NewDF, SF); 1006 1007 // Any uses of DF need to change to NewDF, with cast 1008 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDF, 1009 DGV->getType())); 1010 1011 // DF will conflict with NewDF because they both had the same. We must 1012 // erase this now so ForceRenaming doesn't assert because DF might 1013 // not have internal linkage. 1014 if (GlobalVariable *Var = dyn_cast<GlobalVariable>(DGV)) 1015 Var->eraseFromParent(); 1016 else 1017 cast<Function>(DGV)->eraseFromParent(); 1018 1019 // If the symbol table renamed the function, but it is an externally 1020 // visible symbol, DF must be an existing function with internal 1021 // linkage. Rename it. 1022 if (NewDF->getName() != SF->getName() && !NewDF->hasLocalLinkage()) 1023 ForceRenaming(NewDF, SF->getName()); 1024 1025 // Remember this mapping so uses in the source module get remapped 1026 // later by RemapOperand. 1027 ValueMap[SF] = NewDF; 1028 continue; 1029 } 1030 1031 // Not "link from source", keep the one in the DestModule and remap the 1032 // input onto it. 1033 1034 if (isa<GlobalAlias>(DGV)) { 1035 // The only valid mappings are: 1036 // - SF is external declaration, which is effectively a no-op. 1037 // - SF is weak, when we just need to throw SF out. 1038 if (!SF->isDeclaration() && !SF->isWeakForLinker()) 1039 return Error(Err, "Function-Alias Collision on '" + SF->getName() + 1040 "': symbol multiple defined"); 1041 } 1042 1043 // Set calculated linkage 1044 DGV->setLinkage(NewLinkage); 1045 1046 // Make sure to remember this mapping. 1047 ValueMap[SF] = ConstantExpr::getBitCast(DGV, SF->getType()); 1048 } 1049 return false; 1050} 1051 1052// LinkFunctionBody - Copy the source function over into the dest function and 1053// fix up references to values. At this point we know that Dest is an external 1054// function, and that Src is not. 1055static bool LinkFunctionBody(Function *Dest, Function *Src, 1056 std::map<const Value*, Value*> &ValueMap, 1057 std::string *Err) { 1058 assert(Src && Dest && Dest->isDeclaration() && !Src->isDeclaration()); 1059 1060 // Go through and convert function arguments over, remembering the mapping. 1061 Function::arg_iterator DI = Dest->arg_begin(); 1062 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end(); 1063 I != E; ++I, ++DI) { 1064 DI->setName(I->getName()); // Copy the name information over... 1065 1066 // Add a mapping to our local map 1067 ValueMap[I] = DI; 1068 } 1069 1070 // Splice the body of the source function into the dest function. 1071 Dest->getBasicBlockList().splice(Dest->end(), Src->getBasicBlockList()); 1072 1073 // At this point, all of the instructions and values of the function are now 1074 // copied over. The only problem is that they are still referencing values in 1075 // the Source function as operands. Loop through all of the operands of the 1076 // functions and patch them up to point to the local versions... 1077 // 1078 for (Function::iterator BB = Dest->begin(), BE = Dest->end(); BB != BE; ++BB) 1079 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) 1080 for (Instruction::op_iterator OI = I->op_begin(), OE = I->op_end(); 1081 OI != OE; ++OI) 1082 if (!isa<Instruction>(*OI) && !isa<BasicBlock>(*OI)) 1083 *OI = RemapOperand(*OI, ValueMap); 1084 1085 // There is no need to map the arguments anymore. 1086 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end(); 1087 I != E; ++I) 1088 ValueMap.erase(I); 1089 1090 return false; 1091} 1092 1093 1094// LinkFunctionBodies - Link in the function bodies that are defined in the 1095// source module into the DestModule. This consists basically of copying the 1096// function over and fixing up references to values. 1097static bool LinkFunctionBodies(Module *Dest, Module *Src, 1098 std::map<const Value*, Value*> &ValueMap, 1099 std::string *Err) { 1100 1101 // Loop over all of the functions in the src module, mapping them over as we 1102 // go 1103 for (Module::iterator SF = Src->begin(), E = Src->end(); SF != E; ++SF) { 1104 if (!SF->isDeclaration()) { // No body if function is external 1105 Function *DF = dyn_cast<Function>(ValueMap[SF]); // Destination function 1106 1107 // DF not external SF external? 1108 if (DF && DF->isDeclaration()) 1109 // Only provide the function body if there isn't one already. 1110 if (LinkFunctionBody(DF, SF, ValueMap, Err)) 1111 return true; 1112 } 1113 } 1114 return false; 1115} 1116 1117// LinkAppendingVars - If there were any appending global variables, link them 1118// together now. Return true on error. 1119static bool LinkAppendingVars(Module *M, 1120 std::multimap<std::string, GlobalVariable *> &AppendingVars, 1121 std::string *ErrorMsg) { 1122 if (AppendingVars.empty()) return false; // Nothing to do. 1123 1124 // Loop over the multimap of appending vars, processing any variables with the 1125 // same name, forming a new appending global variable with both of the 1126 // initializers merged together, then rewrite references to the old variables 1127 // and delete them. 1128 std::vector<Constant*> Inits; 1129 while (AppendingVars.size() > 1) { 1130 // Get the first two elements in the map... 1131 std::multimap<std::string, 1132 GlobalVariable*>::iterator Second = AppendingVars.begin(), First=Second++; 1133 1134 // If the first two elements are for different names, there is no pair... 1135 // Otherwise there is a pair, so link them together... 1136 if (First->first == Second->first) { 1137 GlobalVariable *G1 = First->second, *G2 = Second->second; 1138 const ArrayType *T1 = cast<ArrayType>(G1->getType()->getElementType()); 1139 const ArrayType *T2 = cast<ArrayType>(G2->getType()->getElementType()); 1140 1141 // Check to see that they two arrays agree on type... 1142 if (T1->getElementType() != T2->getElementType()) 1143 return Error(ErrorMsg, 1144 "Appending variables with different element types need to be linked!"); 1145 if (G1->isConstant() != G2->isConstant()) 1146 return Error(ErrorMsg, 1147 "Appending variables linked with different const'ness!"); 1148 1149 if (G1->getAlignment() != G2->getAlignment()) 1150 return Error(ErrorMsg, 1151 "Appending variables with different alignment need to be linked!"); 1152 1153 if (G1->getVisibility() != G2->getVisibility()) 1154 return Error(ErrorMsg, 1155 "Appending variables with different visibility need to be linked!"); 1156 1157 if (G1->getSection() != G2->getSection()) 1158 return Error(ErrorMsg, 1159 "Appending variables with different section name need to be linked!"); 1160 1161 unsigned NewSize = T1->getNumElements() + T2->getNumElements(); 1162 ArrayType *NewType = ArrayType::get(T1->getElementType(), 1163 NewSize); 1164 1165 G1->setName(""); // Clear G1's name in case of a conflict! 1166 1167 // Create the new global variable... 1168 GlobalVariable *NG = 1169 new GlobalVariable(*M, NewType, G1->isConstant(), G1->getLinkage(), 1170 /*init*/0, First->first, 0, G1->isThreadLocal(), 1171 G1->getType()->getAddressSpace()); 1172 1173 // Propagate alignment, visibility and section info. 1174 CopyGVAttributes(NG, G1); 1175 1176 // Merge the initializer... 1177 Inits.reserve(NewSize); 1178 if (ConstantArray *I = dyn_cast<ConstantArray>(G1->getInitializer())) { 1179 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i) 1180 Inits.push_back(I->getOperand(i)); 1181 } else { 1182 assert(isa<ConstantAggregateZero>(G1->getInitializer())); 1183 Constant *CV = Constant::getNullValue(T1->getElementType()); 1184 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i) 1185 Inits.push_back(CV); 1186 } 1187 if (ConstantArray *I = dyn_cast<ConstantArray>(G2->getInitializer())) { 1188 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i) 1189 Inits.push_back(I->getOperand(i)); 1190 } else { 1191 assert(isa<ConstantAggregateZero>(G2->getInitializer())); 1192 Constant *CV = Constant::getNullValue(T2->getElementType()); 1193 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i) 1194 Inits.push_back(CV); 1195 } 1196 NG->setInitializer(ConstantArray::get(NewType, Inits)); 1197 Inits.clear(); 1198 1199 // Replace any uses of the two global variables with uses of the new 1200 // global... 1201 1202 // FIXME: This should rewrite simple/straight-forward uses such as 1203 // getelementptr instructions to not use the Cast! 1204 G1->replaceAllUsesWith(ConstantExpr::getBitCast(NG, 1205 G1->getType())); 1206 G2->replaceAllUsesWith(ConstantExpr::getBitCast(NG, 1207 G2->getType())); 1208 1209 // Remove the two globals from the module now... 1210 M->getGlobalList().erase(G1); 1211 M->getGlobalList().erase(G2); 1212 1213 // Put the new global into the AppendingVars map so that we can handle 1214 // linking of more than two vars... 1215 Second->second = NG; 1216 } 1217 AppendingVars.erase(First); 1218 } 1219 1220 return false; 1221} 1222 1223static bool ResolveAliases(Module *Dest) { 1224 for (Module::alias_iterator I = Dest->alias_begin(), E = Dest->alias_end(); 1225 I != E; ++I) 1226 if (const GlobalValue *GV = I->resolveAliasedGlobal()) 1227 if (GV != I && !GV->isDeclaration()) 1228 I->replaceAllUsesWith(const_cast<GlobalValue*>(GV)); 1229 1230 return false; 1231} 1232 1233// LinkModules - This function links two modules together, with the resulting 1234// left module modified to be the composite of the two input modules. If an 1235// error occurs, true is returned and ErrorMsg (if not null) is set to indicate 1236// the problem. Upon failure, the Dest module could be in a modified state, and 1237// shouldn't be relied on to be consistent. 1238bool 1239Linker::LinkModules(Module *Dest, Module *Src, std::string *ErrorMsg) { 1240 assert(Dest != 0 && "Invalid Destination module"); 1241 assert(Src != 0 && "Invalid Source Module"); 1242 1243 if (Dest->getDataLayout().empty()) { 1244 if (!Src->getDataLayout().empty()) { 1245 Dest->setDataLayout(Src->getDataLayout()); 1246 } else { 1247 std::string DataLayout; 1248 1249 if (Dest->getEndianness() == Module::AnyEndianness) { 1250 if (Src->getEndianness() == Module::BigEndian) 1251 DataLayout.append("E"); 1252 else if (Src->getEndianness() == Module::LittleEndian) 1253 DataLayout.append("e"); 1254 } 1255 1256 if (Dest->getPointerSize() == Module::AnyPointerSize) { 1257 if (Src->getPointerSize() == Module::Pointer64) 1258 DataLayout.append(DataLayout.length() == 0 ? "p:64:64" : "-p:64:64"); 1259 else if (Src->getPointerSize() == Module::Pointer32) 1260 DataLayout.append(DataLayout.length() == 0 ? "p:32:32" : "-p:32:32"); 1261 } 1262 Dest->setDataLayout(DataLayout); 1263 } 1264 } 1265 1266 // Copy the target triple from the source to dest if the dest's is empty. 1267 if (Dest->getTargetTriple().empty() && !Src->getTargetTriple().empty()) 1268 Dest->setTargetTriple(Src->getTargetTriple()); 1269 1270 if (!Src->getDataLayout().empty() && !Dest->getDataLayout().empty() && 1271 Src->getDataLayout() != Dest->getDataLayout()) 1272 errs() << "WARNING: Linking two modules of different data layouts!\n"; 1273 if (!Src->getTargetTriple().empty() && 1274 Dest->getTargetTriple() != Src->getTargetTriple()) 1275 errs() << "WARNING: Linking two modules of different target triples!\n"; 1276 1277 // Append the module inline asm string. 1278 if (!Src->getModuleInlineAsm().empty()) { 1279 if (Dest->getModuleInlineAsm().empty()) 1280 Dest->setModuleInlineAsm(Src->getModuleInlineAsm()); 1281 else 1282 Dest->setModuleInlineAsm(Dest->getModuleInlineAsm()+"\n"+ 1283 Src->getModuleInlineAsm()); 1284 } 1285 1286 // Update the destination module's dependent libraries list with the libraries 1287 // from the source module. There's no opportunity for duplicates here as the 1288 // Module ensures that duplicate insertions are discarded. 1289 for (Module::lib_iterator SI = Src->lib_begin(), SE = Src->lib_end(); 1290 SI != SE; ++SI) 1291 Dest->addLibrary(*SI); 1292 1293 // LinkTypes - Go through the symbol table of the Src module and see if any 1294 // types are named in the src module that are not named in the Dst module. 1295 // Make sure there are no type name conflicts. 1296 if (LinkTypes(Dest, Src, ErrorMsg)) 1297 return true; 1298 1299 // ValueMap - Mapping of values from what they used to be in Src, to what they 1300 // are now in Dest. 1301 std::map<const Value*, Value*> ValueMap; 1302 1303 // AppendingVars - Keep track of global variables in the destination module 1304 // with appending linkage. After the module is linked together, they are 1305 // appended and the module is rewritten. 1306 std::multimap<std::string, GlobalVariable *> AppendingVars; 1307 for (Module::global_iterator I = Dest->global_begin(), E = Dest->global_end(); 1308 I != E; ++I) { 1309 // Add all of the appending globals already in the Dest module to 1310 // AppendingVars. 1311 if (I->hasAppendingLinkage()) 1312 AppendingVars.insert(std::make_pair(I->getName(), I)); 1313 } 1314 1315 // Insert all of the named mdnoes in Src into the Dest module. 1316 LinkNamedMDNodes(Dest, Src); 1317 1318 // Insert all of the globals in src into the Dest module... without linking 1319 // initializers (which could refer to functions not yet mapped over). 1320 if (LinkGlobals(Dest, Src, ValueMap, AppendingVars, ErrorMsg)) 1321 return true; 1322 1323 // Link the functions together between the two modules, without doing function 1324 // bodies... this just adds external function prototypes to the Dest 1325 // function... We do this so that when we begin processing function bodies, 1326 // all of the global values that may be referenced are available in our 1327 // ValueMap. 1328 if (LinkFunctionProtos(Dest, Src, ValueMap, ErrorMsg)) 1329 return true; 1330 1331 // If there were any alias, link them now. We really need to do this now, 1332 // because all of the aliases that may be referenced need to be available in 1333 // ValueMap 1334 if (LinkAlias(Dest, Src, ValueMap, ErrorMsg)) return true; 1335 1336 // Update the initializers in the Dest module now that all globals that may 1337 // be referenced are in Dest. 1338 if (LinkGlobalInits(Dest, Src, ValueMap, ErrorMsg)) return true; 1339 1340 // Link in the function bodies that are defined in the source module into the 1341 // DestModule. This consists basically of copying the function over and 1342 // fixing up references to values. 1343 if (LinkFunctionBodies(Dest, Src, ValueMap, ErrorMsg)) return true; 1344 1345 // If there were any appending global variables, link them together now. 1346 if (LinkAppendingVars(Dest, AppendingVars, ErrorMsg)) return true; 1347 1348 // Resolve all uses of aliases with aliasees 1349 if (ResolveAliases(Dest)) return true; 1350 1351 // If the source library's module id is in the dependent library list of the 1352 // destination library, remove it since that module is now linked in. 1353 sys::Path modId; 1354 modId.set(Src->getModuleIdentifier()); 1355 if (!modId.isEmpty()) 1356 Dest->removeLibrary(modId.getBasename()); 1357 1358 return false; 1359} 1360 1361// vim: sw=2 1362