LinkModules.cpp revision ece76b00b4343749f7d3fcf16ce9437248d7aff5
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->getNumOperands(); i != e; ++i) 542 DestNMD->addOperand(SrcNMD->getOperand(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(); 667 668 // If the symbol table renamed the global, but it is an externally visible 669 // symbol, DGV must be an existing global with internal linkage. Rename. 670 if (NewDGV->getName() != SGV->getName() && !NewDGV->hasLocalLinkage()) 671 ForceRenaming(NewDGV, SGV->getName()); 672 673 // Inherit const as appropriate. 674 NewDGV->setConstant(SGV->isConstant()); 675 676 // Make sure to remember this mapping. 677 ValueMap[SGV] = NewDGV; 678 continue; 679 } 680 681 // Not "link from source", keep the one in the DestModule and remap the 682 // input onto it. 683 684 // Special case for const propagation. 685 if (GlobalVariable *DGVar = dyn_cast<GlobalVariable>(DGV)) 686 if (DGVar->isDeclaration() && SGV->isConstant() && !DGVar->isConstant()) 687 DGVar->setConstant(true); 688 689 // SGV is global, but DGV is alias. 690 if (isa<GlobalAlias>(DGV)) { 691 // The only valid mappings are: 692 // - SGV is external declaration, which is effectively a no-op. 693 // - SGV is weak, when we just need to throw SGV out. 694 if (!SGV->isDeclaration() && !SGV->isWeakForLinker()) 695 return Error(Err, "Global-Alias Collision on '" + SGV->getName() + 696 "': symbol multiple defined"); 697 } 698 699 // Set calculated linkage 700 DGV->setLinkage(NewLinkage); 701 702 // Make sure to remember this mapping... 703 ValueMap[SGV] = ConstantExpr::getBitCast(DGV, SGV->getType()); 704 } 705 return false; 706} 707 708static GlobalValue::LinkageTypes 709CalculateAliasLinkage(const GlobalValue *SGV, const GlobalValue *DGV) { 710 GlobalValue::LinkageTypes SL = SGV->getLinkage(); 711 GlobalValue::LinkageTypes DL = DGV->getLinkage(); 712 if (SL == GlobalValue::ExternalLinkage || DL == GlobalValue::ExternalLinkage) 713 return GlobalValue::ExternalLinkage; 714 else if (SL == GlobalValue::WeakAnyLinkage || 715 DL == GlobalValue::WeakAnyLinkage) 716 return GlobalValue::WeakAnyLinkage; 717 else if (SL == GlobalValue::WeakODRLinkage || 718 DL == GlobalValue::WeakODRLinkage) 719 return GlobalValue::WeakODRLinkage; 720 else if (SL == GlobalValue::InternalLinkage && 721 DL == GlobalValue::InternalLinkage) 722 return GlobalValue::InternalLinkage; 723 else if (SL == GlobalValue::LinkerPrivateLinkage && 724 DL == GlobalValue::LinkerPrivateLinkage) 725 return GlobalValue::LinkerPrivateLinkage; 726 else { 727 assert (SL == GlobalValue::PrivateLinkage && 728 DL == GlobalValue::PrivateLinkage && "Unexpected linkage type"); 729 return GlobalValue::PrivateLinkage; 730 } 731} 732 733// LinkAlias - Loop through the alias in the src module and link them into the 734// dest module. We're assuming, that all functions/global variables were already 735// linked in. 736static bool LinkAlias(Module *Dest, const Module *Src, 737 std::map<const Value*, Value*> &ValueMap, 738 std::string *Err) { 739 // Loop over all alias in the src module 740 for (Module::const_alias_iterator I = Src->alias_begin(), 741 E = Src->alias_end(); I != E; ++I) { 742 const GlobalAlias *SGA = I; 743 const GlobalValue *SAliasee = SGA->getAliasedGlobal(); 744 GlobalAlias *NewGA = NULL; 745 746 // Globals were already linked, thus we can just query ValueMap for variant 747 // of SAliasee in Dest. 748 std::map<const Value*,Value*>::const_iterator VMI = ValueMap.find(SAliasee); 749 assert(VMI != ValueMap.end() && "Aliasee not linked"); 750 GlobalValue* DAliasee = cast<GlobalValue>(VMI->second); 751 GlobalValue* DGV = NULL; 752 753 // Try to find something 'similar' to SGA in destination module. 754 if (!DGV && !SGA->hasLocalLinkage()) { 755 DGV = Dest->getNamedAlias(SGA->getName()); 756 757 // If types don't agree due to opaque types, try to resolve them. 758 if (DGV && DGV->getType() != SGA->getType()) 759 RecursiveResolveTypes(SGA->getType(), DGV->getType()); 760 } 761 762 if (!DGV && !SGA->hasLocalLinkage()) { 763 DGV = Dest->getGlobalVariable(SGA->getName()); 764 765 // If types don't agree due to opaque types, try to resolve them. 766 if (DGV && DGV->getType() != SGA->getType()) 767 RecursiveResolveTypes(SGA->getType(), DGV->getType()); 768 } 769 770 if (!DGV && !SGA->hasLocalLinkage()) { 771 DGV = Dest->getFunction(SGA->getName()); 772 773 // If types don't agree due to opaque types, try to resolve them. 774 if (DGV && DGV->getType() != SGA->getType()) 775 RecursiveResolveTypes(SGA->getType(), DGV->getType()); 776 } 777 778 // No linking to be performed on internal stuff. 779 if (DGV && DGV->hasLocalLinkage()) 780 DGV = NULL; 781 782 if (GlobalAlias *DGA = dyn_cast_or_null<GlobalAlias>(DGV)) { 783 // Types are known to be the same, check whether aliasees equal. As 784 // globals are already linked we just need query ValueMap to find the 785 // mapping. 786 if (DAliasee == DGA->getAliasedGlobal()) { 787 // This is just two copies of the same alias. Propagate linkage, if 788 // necessary. 789 DGA->setLinkage(CalculateAliasLinkage(SGA, DGA)); 790 791 NewGA = DGA; 792 // Proceed to 'common' steps 793 } else 794 return Error(Err, "Alias Collision on '" + SGA->getName()+ 795 "': aliases have different aliasees"); 796 } else if (GlobalVariable *DGVar = dyn_cast_or_null<GlobalVariable>(DGV)) { 797 // The only allowed way is to link alias with external declaration or weak 798 // symbol.. 799 if (DGVar->isDeclaration() || DGVar->isWeakForLinker()) { 800 // But only if aliasee is global too... 801 if (!isa<GlobalVariable>(DAliasee)) 802 return Error(Err, "Global-Alias Collision on '" + SGA->getName() + 803 "': aliasee is not global variable"); 804 805 NewGA = new GlobalAlias(SGA->getType(), SGA->getLinkage(), 806 SGA->getName(), DAliasee, Dest); 807 CopyGVAttributes(NewGA, SGA); 808 809 // Any uses of DGV need to change to NewGA, with cast, if needed. 810 if (SGA->getType() != DGVar->getType()) 811 DGVar->replaceAllUsesWith(ConstantExpr::getBitCast(NewGA, 812 DGVar->getType())); 813 else 814 DGVar->replaceAllUsesWith(NewGA); 815 816 // DGVar will conflict with NewGA because they both had the same 817 // name. We must erase this now so ForceRenaming doesn't assert 818 // because DGV might not have internal linkage. 819 DGVar->eraseFromParent(); 820 821 // Proceed to 'common' steps 822 } else 823 return Error(Err, "Global-Alias Collision on '" + SGA->getName() + 824 "': symbol multiple defined"); 825 } else if (Function *DF = dyn_cast_or_null<Function>(DGV)) { 826 // The only allowed way is to link alias with external declaration or weak 827 // symbol... 828 if (DF->isDeclaration() || DF->isWeakForLinker()) { 829 // But only if aliasee is function too... 830 if (!isa<Function>(DAliasee)) 831 return Error(Err, "Function-Alias Collision on '" + SGA->getName() + 832 "': aliasee is not function"); 833 834 NewGA = new GlobalAlias(SGA->getType(), SGA->getLinkage(), 835 SGA->getName(), DAliasee, Dest); 836 CopyGVAttributes(NewGA, SGA); 837 838 // Any uses of DF need to change to NewGA, with cast, if needed. 839 if (SGA->getType() != DF->getType()) 840 DF->replaceAllUsesWith(ConstantExpr::getBitCast(NewGA, 841 DF->getType())); 842 else 843 DF->replaceAllUsesWith(NewGA); 844 845 // DF will conflict with NewGA because they both had the same 846 // name. We must erase this now so ForceRenaming doesn't assert 847 // because DF might not have internal linkage. 848 DF->eraseFromParent(); 849 850 // Proceed to 'common' steps 851 } else 852 return Error(Err, "Function-Alias Collision on '" + SGA->getName() + 853 "': symbol multiple defined"); 854 } else { 855 // No linking to be performed, simply create an identical version of the 856 // alias over in the dest module... 857 858 NewGA = new GlobalAlias(SGA->getType(), SGA->getLinkage(), 859 SGA->getName(), DAliasee, Dest); 860 CopyGVAttributes(NewGA, SGA); 861 862 // Proceed to 'common' steps 863 } 864 865 assert(NewGA && "No alias was created in destination module!"); 866 867 // If the symbol table renamed the alias, but it is an externally visible 868 // symbol, DGA must be an global value with internal linkage. Rename it. 869 if (NewGA->getName() != SGA->getName() && 870 !NewGA->hasLocalLinkage()) 871 ForceRenaming(NewGA, SGA->getName()); 872 873 // Remember this mapping so uses in the source module get remapped 874 // later by RemapOperand. 875 ValueMap[SGA] = NewGA; 876 } 877 878 return false; 879} 880 881 882// LinkGlobalInits - Update the initializers in the Dest module now that all 883// globals that may be referenced are in Dest. 884static bool LinkGlobalInits(Module *Dest, const Module *Src, 885 std::map<const Value*, Value*> &ValueMap, 886 std::string *Err) { 887 // Loop over all of the globals in the src module, mapping them over as we go 888 for (Module::const_global_iterator I = Src->global_begin(), 889 E = Src->global_end(); I != E; ++I) { 890 const GlobalVariable *SGV = I; 891 892 if (SGV->hasInitializer()) { // Only process initialized GV's 893 // Figure out what the initializer looks like in the dest module... 894 Constant *SInit = 895 cast<Constant>(RemapOperand(SGV->getInitializer(), ValueMap)); 896 // Grab destination global variable or alias. 897 GlobalValue *DGV = cast<GlobalValue>(ValueMap[SGV]->stripPointerCasts()); 898 899 // If dest if global variable, check that initializers match. 900 if (GlobalVariable *DGVar = dyn_cast<GlobalVariable>(DGV)) { 901 if (DGVar->hasInitializer()) { 902 if (SGV->hasExternalLinkage()) { 903 if (DGVar->getInitializer() != SInit) 904 return Error(Err, "Global Variable Collision on '" + 905 SGV->getName() + 906 "': global variables have different initializers"); 907 } else if (DGVar->isWeakForLinker()) { 908 // Nothing is required, mapped values will take the new global 909 // automatically. 910 } else if (SGV->isWeakForLinker()) { 911 // Nothing is required, mapped values will take the new global 912 // automatically. 913 } else if (DGVar->hasAppendingLinkage()) { 914 llvm_unreachable("Appending linkage unimplemented!"); 915 } else { 916 llvm_unreachable("Unknown linkage!"); 917 } 918 } else { 919 // Copy the initializer over now... 920 DGVar->setInitializer(SInit); 921 } 922 } else { 923 // Destination is alias, the only valid situation is when source is 924 // weak. Also, note, that we already checked linkage in LinkGlobals(), 925 // thus we assert here. 926 // FIXME: Should we weaken this assumption, 'dereference' alias and 927 // check for initializer of aliasee? 928 assert(SGV->isWeakForLinker()); 929 } 930 } 931 } 932 return false; 933} 934 935// LinkFunctionProtos - Link the functions together between the two modules, 936// without doing function bodies... this just adds external function prototypes 937// to the Dest function... 938// 939static bool LinkFunctionProtos(Module *Dest, const Module *Src, 940 std::map<const Value*, Value*> &ValueMap, 941 std::string *Err) { 942 ValueSymbolTable &DestSymTab = Dest->getValueSymbolTable(); 943 944 // Loop over all of the functions in the src module, mapping them over 945 for (Module::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) { 946 const Function *SF = I; // SrcFunction 947 GlobalValue *DGV = 0; 948 949 // Check to see if may have to link the function with the global, alias or 950 // function. 951 if (SF->hasName() && !SF->hasLocalLinkage()) 952 DGV = cast_or_null<GlobalValue>(DestSymTab.lookup(SF->getName())); 953 954 // If we found a global with the same name in the dest module, but it has 955 // internal linkage, we are really not doing any linkage here. 956 if (DGV && DGV->hasLocalLinkage()) 957 DGV = 0; 958 959 // If types don't agree due to opaque types, try to resolve them. 960 if (DGV && DGV->getType() != SF->getType()) 961 RecursiveResolveTypes(SF->getType(), DGV->getType()); 962 963 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; 964 bool LinkFromSrc = false; 965 if (GetLinkageResult(DGV, SF, NewLinkage, LinkFromSrc, Err)) 966 return true; 967 968 // If there is no linkage to be performed, just bring over SF without 969 // modifying it. 970 if (DGV == 0) { 971 // Function does not already exist, simply insert an function signature 972 // identical to SF into the dest module. 973 Function *NewDF = Function::Create(SF->getFunctionType(), 974 SF->getLinkage(), 975 SF->getName(), Dest); 976 CopyGVAttributes(NewDF, SF); 977 978 // If the LLVM runtime renamed the function, but it is an externally 979 // visible symbol, DF must be an existing function with internal linkage. 980 // Rename it. 981 if (!NewDF->hasLocalLinkage() && NewDF->getName() != SF->getName()) 982 ForceRenaming(NewDF, SF->getName()); 983 984 // ... and remember this mapping... 985 ValueMap[SF] = NewDF; 986 continue; 987 } 988 989 // If the visibilities of the symbols disagree and the destination is a 990 // prototype, take the visibility of its input. 991 if (DGV->isDeclaration()) 992 DGV->setVisibility(SF->getVisibility()); 993 994 if (LinkFromSrc) { 995 if (isa<GlobalAlias>(DGV)) 996 return Error(Err, "Function-Alias Collision on '" + SF->getName() + 997 "': symbol multiple defined"); 998 999 // We have a definition of the same name but different type in the 1000 // source module. Copy the prototype to the destination and replace 1001 // uses of the destination's prototype with the new prototype. 1002 Function *NewDF = Function::Create(SF->getFunctionType(), NewLinkage, 1003 SF->getName(), Dest); 1004 CopyGVAttributes(NewDF, SF); 1005 1006 // Any uses of DF need to change to NewDF, with cast 1007 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDF, 1008 DGV->getType())); 1009 1010 // DF will conflict with NewDF because they both had the same. We must 1011 // erase this now so ForceRenaming doesn't assert because DF might 1012 // not have internal linkage. 1013 if (GlobalVariable *Var = dyn_cast<GlobalVariable>(DGV)) 1014 Var->eraseFromParent(); 1015 else 1016 cast<Function>(DGV)->eraseFromParent(); 1017 1018 // If the symbol table renamed the function, but it is an externally 1019 // visible symbol, DF must be an existing function with internal 1020 // linkage. Rename it. 1021 if (NewDF->getName() != SF->getName() && !NewDF->hasLocalLinkage()) 1022 ForceRenaming(NewDF, SF->getName()); 1023 1024 // Remember this mapping so uses in the source module get remapped 1025 // later by RemapOperand. 1026 ValueMap[SF] = NewDF; 1027 continue; 1028 } 1029 1030 // Not "link from source", keep the one in the DestModule and remap the 1031 // input onto it. 1032 1033 if (isa<GlobalAlias>(DGV)) { 1034 // The only valid mappings are: 1035 // - SF is external declaration, which is effectively a no-op. 1036 // - SF is weak, when we just need to throw SF out. 1037 if (!SF->isDeclaration() && !SF->isWeakForLinker()) 1038 return Error(Err, "Function-Alias Collision on '" + SF->getName() + 1039 "': symbol multiple defined"); 1040 } 1041 1042 // Set calculated linkage 1043 DGV->setLinkage(NewLinkage); 1044 1045 // Make sure to remember this mapping. 1046 ValueMap[SF] = ConstantExpr::getBitCast(DGV, SF->getType()); 1047 } 1048 return false; 1049} 1050 1051// LinkFunctionBody - Copy the source function over into the dest function and 1052// fix up references to values. At this point we know that Dest is an external 1053// function, and that Src is not. 1054static bool LinkFunctionBody(Function *Dest, Function *Src, 1055 std::map<const Value*, Value*> &ValueMap, 1056 std::string *Err) { 1057 assert(Src && Dest && Dest->isDeclaration() && !Src->isDeclaration()); 1058 1059 // Go through and convert function arguments over, remembering the mapping. 1060 Function::arg_iterator DI = Dest->arg_begin(); 1061 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end(); 1062 I != E; ++I, ++DI) { 1063 DI->setName(I->getName()); // Copy the name information over... 1064 1065 // Add a mapping to our local map 1066 ValueMap[I] = DI; 1067 } 1068 1069 // Splice the body of the source function into the dest function. 1070 Dest->getBasicBlockList().splice(Dest->end(), Src->getBasicBlockList()); 1071 1072 // At this point, all of the instructions and values of the function are now 1073 // copied over. The only problem is that they are still referencing values in 1074 // the Source function as operands. Loop through all of the operands of the 1075 // functions and patch them up to point to the local versions... 1076 // 1077 for (Function::iterator BB = Dest->begin(), BE = Dest->end(); BB != BE; ++BB) 1078 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) 1079 for (Instruction::op_iterator OI = I->op_begin(), OE = I->op_end(); 1080 OI != OE; ++OI) 1081 if (!isa<Instruction>(*OI) && !isa<BasicBlock>(*OI)) 1082 *OI = RemapOperand(*OI, ValueMap); 1083 1084 // There is no need to map the arguments anymore. 1085 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end(); 1086 I != E; ++I) 1087 ValueMap.erase(I); 1088 1089 return false; 1090} 1091 1092 1093// LinkFunctionBodies - Link in the function bodies that are defined in the 1094// source module into the DestModule. This consists basically of copying the 1095// function over and fixing up references to values. 1096static bool LinkFunctionBodies(Module *Dest, Module *Src, 1097 std::map<const Value*, Value*> &ValueMap, 1098 std::string *Err) { 1099 1100 // Loop over all of the functions in the src module, mapping them over as we 1101 // go 1102 for (Module::iterator SF = Src->begin(), E = Src->end(); SF != E; ++SF) { 1103 if (!SF->isDeclaration()) { // No body if function is external 1104 Function *DF = dyn_cast<Function>(ValueMap[SF]); // Destination function 1105 1106 // DF not external SF external? 1107 if (DF && DF->isDeclaration()) 1108 // Only provide the function body if there isn't one already. 1109 if (LinkFunctionBody(DF, SF, ValueMap, Err)) 1110 return true; 1111 } 1112 } 1113 return false; 1114} 1115 1116// LinkAppendingVars - If there were any appending global variables, link them 1117// together now. Return true on error. 1118static bool LinkAppendingVars(Module *M, 1119 std::multimap<std::string, GlobalVariable *> &AppendingVars, 1120 std::string *ErrorMsg) { 1121 if (AppendingVars.empty()) return false; // Nothing to do. 1122 1123 // Loop over the multimap of appending vars, processing any variables with the 1124 // same name, forming a new appending global variable with both of the 1125 // initializers merged together, then rewrite references to the old variables 1126 // and delete them. 1127 std::vector<Constant*> Inits; 1128 while (AppendingVars.size() > 1) { 1129 // Get the first two elements in the map... 1130 std::multimap<std::string, 1131 GlobalVariable*>::iterator Second = AppendingVars.begin(), First=Second++; 1132 1133 // If the first two elements are for different names, there is no pair... 1134 // Otherwise there is a pair, so link them together... 1135 if (First->first == Second->first) { 1136 GlobalVariable *G1 = First->second, *G2 = Second->second; 1137 const ArrayType *T1 = cast<ArrayType>(G1->getType()->getElementType()); 1138 const ArrayType *T2 = cast<ArrayType>(G2->getType()->getElementType()); 1139 1140 // Check to see that they two arrays agree on type... 1141 if (T1->getElementType() != T2->getElementType()) 1142 return Error(ErrorMsg, 1143 "Appending variables with different element types need to be linked!"); 1144 if (G1->isConstant() != G2->isConstant()) 1145 return Error(ErrorMsg, 1146 "Appending variables linked with different const'ness!"); 1147 1148 if (G1->getAlignment() != G2->getAlignment()) 1149 return Error(ErrorMsg, 1150 "Appending variables with different alignment need to be linked!"); 1151 1152 if (G1->getVisibility() != G2->getVisibility()) 1153 return Error(ErrorMsg, 1154 "Appending variables with different visibility need to be linked!"); 1155 1156 if (G1->getSection() != G2->getSection()) 1157 return Error(ErrorMsg, 1158 "Appending variables with different section name need to be linked!"); 1159 1160 unsigned NewSize = T1->getNumElements() + T2->getNumElements(); 1161 ArrayType *NewType = ArrayType::get(T1->getElementType(), 1162 NewSize); 1163 1164 G1->setName(""); // Clear G1's name in case of a conflict! 1165 1166 // Create the new global variable... 1167 GlobalVariable *NG = 1168 new GlobalVariable(*M, NewType, G1->isConstant(), G1->getLinkage(), 1169 /*init*/0, First->first, 0, G1->isThreadLocal(), 1170 G1->getType()->getAddressSpace()); 1171 1172 // Propagate alignment, visibility and section info. 1173 CopyGVAttributes(NG, G1); 1174 1175 // Merge the initializer... 1176 Inits.reserve(NewSize); 1177 if (ConstantArray *I = dyn_cast<ConstantArray>(G1->getInitializer())) { 1178 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i) 1179 Inits.push_back(I->getOperand(i)); 1180 } else { 1181 assert(isa<ConstantAggregateZero>(G1->getInitializer())); 1182 Constant *CV = Constant::getNullValue(T1->getElementType()); 1183 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i) 1184 Inits.push_back(CV); 1185 } 1186 if (ConstantArray *I = dyn_cast<ConstantArray>(G2->getInitializer())) { 1187 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i) 1188 Inits.push_back(I->getOperand(i)); 1189 } else { 1190 assert(isa<ConstantAggregateZero>(G2->getInitializer())); 1191 Constant *CV = Constant::getNullValue(T2->getElementType()); 1192 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i) 1193 Inits.push_back(CV); 1194 } 1195 NG->setInitializer(ConstantArray::get(NewType, Inits)); 1196 Inits.clear(); 1197 1198 // Replace any uses of the two global variables with uses of the new 1199 // global... 1200 1201 // FIXME: This should rewrite simple/straight-forward uses such as 1202 // getelementptr instructions to not use the Cast! 1203 G1->replaceAllUsesWith(ConstantExpr::getBitCast(NG, 1204 G1->getType())); 1205 G2->replaceAllUsesWith(ConstantExpr::getBitCast(NG, 1206 G2->getType())); 1207 1208 // Remove the two globals from the module now... 1209 M->getGlobalList().erase(G1); 1210 M->getGlobalList().erase(G2); 1211 1212 // Put the new global into the AppendingVars map so that we can handle 1213 // linking of more than two vars... 1214 Second->second = NG; 1215 } 1216 AppendingVars.erase(First); 1217 } 1218 1219 return false; 1220} 1221 1222static bool ResolveAliases(Module *Dest) { 1223 for (Module::alias_iterator I = Dest->alias_begin(), E = Dest->alias_end(); 1224 I != E; ++I) 1225 if (const GlobalValue *GV = I->resolveAliasedGlobal()) 1226 if (GV != I && !GV->isDeclaration()) 1227 I->replaceAllUsesWith(const_cast<GlobalValue*>(GV)); 1228 1229 return false; 1230} 1231 1232// LinkModules - This function links two modules together, with the resulting 1233// left module modified to be the composite of the two input modules. If an 1234// error occurs, true is returned and ErrorMsg (if not null) is set to indicate 1235// the problem. Upon failure, the Dest module could be in a modified state, and 1236// shouldn't be relied on to be consistent. 1237bool 1238Linker::LinkModules(Module *Dest, Module *Src, std::string *ErrorMsg) { 1239 assert(Dest != 0 && "Invalid Destination module"); 1240 assert(Src != 0 && "Invalid Source Module"); 1241 1242 if (Dest->getDataLayout().empty()) { 1243 if (!Src->getDataLayout().empty()) { 1244 Dest->setDataLayout(Src->getDataLayout()); 1245 } else { 1246 std::string DataLayout; 1247 1248 if (Dest->getEndianness() == Module::AnyEndianness) { 1249 if (Src->getEndianness() == Module::BigEndian) 1250 DataLayout.append("E"); 1251 else if (Src->getEndianness() == Module::LittleEndian) 1252 DataLayout.append("e"); 1253 } 1254 1255 if (Dest->getPointerSize() == Module::AnyPointerSize) { 1256 if (Src->getPointerSize() == Module::Pointer64) 1257 DataLayout.append(DataLayout.length() == 0 ? "p:64:64" : "-p:64:64"); 1258 else if (Src->getPointerSize() == Module::Pointer32) 1259 DataLayout.append(DataLayout.length() == 0 ? "p:32:32" : "-p:32:32"); 1260 } 1261 Dest->setDataLayout(DataLayout); 1262 } 1263 } 1264 1265 // Copy the target triple from the source to dest if the dest's is empty. 1266 if (Dest->getTargetTriple().empty() && !Src->getTargetTriple().empty()) 1267 Dest->setTargetTriple(Src->getTargetTriple()); 1268 1269 if (!Src->getDataLayout().empty() && !Dest->getDataLayout().empty() && 1270 Src->getDataLayout() != Dest->getDataLayout()) 1271 errs() << "WARNING: Linking two modules of different data layouts!\n"; 1272 if (!Src->getTargetTriple().empty() && 1273 Dest->getTargetTriple() != Src->getTargetTriple()) 1274 errs() << "WARNING: Linking two modules of different target triples!\n"; 1275 1276 // Append the module inline asm string. 1277 if (!Src->getModuleInlineAsm().empty()) { 1278 if (Dest->getModuleInlineAsm().empty()) 1279 Dest->setModuleInlineAsm(Src->getModuleInlineAsm()); 1280 else 1281 Dest->setModuleInlineAsm(Dest->getModuleInlineAsm()+"\n"+ 1282 Src->getModuleInlineAsm()); 1283 } 1284 1285 // Update the destination module's dependent libraries list with the libraries 1286 // from the source module. There's no opportunity for duplicates here as the 1287 // Module ensures that duplicate insertions are discarded. 1288 for (Module::lib_iterator SI = Src->lib_begin(), SE = Src->lib_end(); 1289 SI != SE; ++SI) 1290 Dest->addLibrary(*SI); 1291 1292 // LinkTypes - Go through the symbol table of the Src module and see if any 1293 // types are named in the src module that are not named in the Dst module. 1294 // Make sure there are no type name conflicts. 1295 if (LinkTypes(Dest, Src, ErrorMsg)) 1296 return true; 1297 1298 // ValueMap - Mapping of values from what they used to be in Src, to what they 1299 // are now in Dest. 1300 std::map<const Value*, Value*> ValueMap; 1301 1302 // AppendingVars - Keep track of global variables in the destination module 1303 // with appending linkage. After the module is linked together, they are 1304 // appended and the module is rewritten. 1305 std::multimap<std::string, GlobalVariable *> AppendingVars; 1306 for (Module::global_iterator I = Dest->global_begin(), E = Dest->global_end(); 1307 I != E; ++I) { 1308 // Add all of the appending globals already in the Dest module to 1309 // AppendingVars. 1310 if (I->hasAppendingLinkage()) 1311 AppendingVars.insert(std::make_pair(I->getName(), I)); 1312 } 1313 1314 // Insert all of the named mdnoes in Src into the Dest module. 1315 LinkNamedMDNodes(Dest, Src); 1316 1317 // Insert all of the globals in src into the Dest module... without linking 1318 // initializers (which could refer to functions not yet mapped over). 1319 if (LinkGlobals(Dest, Src, ValueMap, AppendingVars, ErrorMsg)) 1320 return true; 1321 1322 // Link the functions together between the two modules, without doing function 1323 // bodies... this just adds external function prototypes to the Dest 1324 // function... We do this so that when we begin processing function bodies, 1325 // all of the global values that may be referenced are available in our 1326 // ValueMap. 1327 if (LinkFunctionProtos(Dest, Src, ValueMap, ErrorMsg)) 1328 return true; 1329 1330 // If there were any alias, link them now. We really need to do this now, 1331 // because all of the aliases that may be referenced need to be available in 1332 // ValueMap 1333 if (LinkAlias(Dest, Src, ValueMap, ErrorMsg)) return true; 1334 1335 // Update the initializers in the Dest module now that all globals that may 1336 // be referenced are in Dest. 1337 if (LinkGlobalInits(Dest, Src, ValueMap, ErrorMsg)) return true; 1338 1339 // Link in the function bodies that are defined in the source module into the 1340 // DestModule. This consists basically of copying the function over and 1341 // fixing up references to values. 1342 if (LinkFunctionBodies(Dest, Src, ValueMap, ErrorMsg)) return true; 1343 1344 // If there were any appending global variables, link them together now. 1345 if (LinkAppendingVars(Dest, AppendingVars, ErrorMsg)) return true; 1346 1347 // Resolve all uses of aliases with aliasees 1348 if (ResolveAliases(Dest)) return true; 1349 1350 // If the source library's module id is in the dependent library list of the 1351 // destination library, remove it since that module is now linked in. 1352 sys::Path modId; 1353 modId.set(Src->getModuleIdentifier()); 1354 if (!modId.isEmpty()) 1355 Dest->removeLibrary(modId.getBasename()); 1356 1357 return false; 1358} 1359 1360// vim: sw=2 1361