LinkModules.cpp revision ae1132d2b8ae07afd2fe9a7cb434d849f884bfa0
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/Module.h" 23#include "llvm/TypeSymbolTable.h" 24#include "llvm/ValueSymbolTable.h" 25#include "llvm/Instructions.h" 26#include "llvm/Assembly/Writer.h" 27#include "llvm/Support/Streams.h" 28#include "llvm/System/Path.h" 29#include "llvm/ADT/DenseMap.h" 30#include <sstream> 31using namespace llvm; 32 33// Error - Simple wrapper function to conditionally assign to E and return true. 34// This just makes error return conditions a little bit simpler... 35static inline bool Error(std::string *E, const std::string &Message) { 36 if (E) *E = Message; 37 return true; 38} 39 40// ToStr - Simple wrapper function to convert a type to a string. 41static std::string ToStr(const Type *Ty, const Module *M) { 42 std::ostringstream OS; 43 WriteTypeSymbolic(OS, Ty, M); 44 return OS.str(); 45} 46 47// 48// Function: ResolveTypes() 49// 50// Description: 51// Attempt to link the two specified types together. 52// 53// Inputs: 54// DestTy - The type to which we wish to resolve. 55// SrcTy - The original type which we want to resolve. 56// 57// Outputs: 58// DestST - The symbol table in which the new type should be placed. 59// 60// Return value: 61// true - There is an error and the types cannot yet be linked. 62// false - No errors. 63// 64static bool ResolveTypes(const Type *DestTy, const Type *SrcTy) { 65 if (DestTy == SrcTy) return false; // If already equal, noop 66 assert(DestTy && SrcTy && "Can't handle null types"); 67 68 if (const OpaqueType *OT = dyn_cast<OpaqueType>(DestTy)) { 69 // Type _is_ in module, just opaque... 70 const_cast<OpaqueType*>(OT)->refineAbstractTypeTo(SrcTy); 71 } else if (const OpaqueType *OT = dyn_cast<OpaqueType>(SrcTy)) { 72 const_cast<OpaqueType*>(OT)->refineAbstractTypeTo(DestTy); 73 } else { 74 return true; // Cannot link types... not-equal and neither is opaque. 75 } 76 return false; 77} 78 79/// LinkerTypeMap - This implements a map of types that is stable 80/// even if types are resolved/refined to other types. This is not a general 81/// purpose map, it is specific to the linker's use. 82namespace { 83class LinkerTypeMap : public AbstractTypeUser { 84 typedef DenseMap<const Type*, PATypeHolder> TheMapTy; 85 TheMapTy TheMap; 86 87 LinkerTypeMap(const LinkerTypeMap&); // DO NOT IMPLEMENT 88 void operator=(const LinkerTypeMap&); // DO NOT IMPLEMENT 89public: 90 LinkerTypeMap() {} 91 ~LinkerTypeMap() { 92 for (DenseMap<const Type*, PATypeHolder>::iterator I = TheMap.begin(), 93 E = TheMap.end(); I != E; ++I) 94 I->first->removeAbstractTypeUser(this); 95 } 96 97 /// lookup - Return the value for the specified type or null if it doesn't 98 /// exist. 99 const Type *lookup(const Type *Ty) const { 100 TheMapTy::const_iterator I = TheMap.find(Ty); 101 if (I != TheMap.end()) return I->second; 102 return 0; 103 } 104 105 /// erase - Remove the specified type, returning true if it was in the set. 106 bool erase(const Type *Ty) { 107 if (!TheMap.erase(Ty)) 108 return false; 109 if (Ty->isAbstract()) 110 Ty->removeAbstractTypeUser(this); 111 return true; 112 } 113 114 /// insert - This returns true if the pointer was new to the set, false if it 115 /// was already in the set. 116 bool insert(const Type *Src, const Type *Dst) { 117 if (!TheMap.insert(std::make_pair(Src, PATypeHolder(Dst))).second) 118 return false; // Already in map. 119 if (Src->isAbstract()) 120 Src->addAbstractTypeUser(this); 121 return true; 122 } 123 124protected: 125 /// refineAbstractType - The callback method invoked when an abstract type is 126 /// resolved to another type. An object must override this method to update 127 /// its internal state to reference NewType instead of OldType. 128 /// 129 virtual void refineAbstractType(const DerivedType *OldTy, 130 const Type *NewTy) { 131 TheMapTy::iterator I = TheMap.find(OldTy); 132 const Type *DstTy = I->second; 133 134 TheMap.erase(I); 135 if (OldTy->isAbstract()) 136 OldTy->removeAbstractTypeUser(this); 137 138 // Don't reinsert into the map if the key is concrete now. 139 if (NewTy->isAbstract()) 140 insert(NewTy, DstTy); 141 } 142 143 /// The other case which AbstractTypeUsers must be aware of is when a type 144 /// makes the transition from being abstract (where it has clients on it's 145 /// AbstractTypeUsers list) to concrete (where it does not). This method 146 /// notifies ATU's when this occurs for a type. 147 virtual void typeBecameConcrete(const DerivedType *AbsTy) { 148 TheMap.erase(AbsTy); 149 AbsTy->removeAbstractTypeUser(this); 150 } 151 152 // for debugging... 153 virtual void dump() const { 154 cerr << "AbstractTypeSet!\n"; 155 } 156}; 157} 158 159 160// RecursiveResolveTypes - This is just like ResolveTypes, except that it 161// recurses down into derived types, merging the used types if the parent types 162// are compatible. 163static bool RecursiveResolveTypesI(const Type *DstTy, const Type *SrcTy, 164 LinkerTypeMap &Pointers) { 165 if (DstTy == SrcTy) return false; // If already equal, noop 166 167 // If we found our opaque type, resolve it now! 168 if (isa<OpaqueType>(DstTy) || isa<OpaqueType>(SrcTy)) 169 return ResolveTypes(DstTy, SrcTy); 170 171 // Two types cannot be resolved together if they are of different primitive 172 // type. For example, we cannot resolve an int to a float. 173 if (DstTy->getTypeID() != SrcTy->getTypeID()) return true; 174 175 // If neither type is abstract, then they really are just different types. 176 if (!DstTy->isAbstract() && !SrcTy->isAbstract()) 177 return true; 178 179 // Otherwise, resolve the used type used by this derived type... 180 switch (DstTy->getTypeID()) { 181 default: 182 return true; 183 case Type::FunctionTyID: { 184 const FunctionType *DstFT = cast<FunctionType>(DstTy); 185 const FunctionType *SrcFT = cast<FunctionType>(SrcTy); 186 if (DstFT->isVarArg() != SrcFT->isVarArg() || 187 DstFT->getNumContainedTypes() != SrcFT->getNumContainedTypes()) 188 return true; 189 190 // Use TypeHolder's so recursive resolution won't break us. 191 PATypeHolder ST(SrcFT), DT(DstFT); 192 for (unsigned i = 0, e = DstFT->getNumContainedTypes(); i != e; ++i) { 193 const Type *SE = ST->getContainedType(i), *DE = DT->getContainedType(i); 194 if (SE != DE && RecursiveResolveTypesI(DE, SE, Pointers)) 195 return true; 196 } 197 return false; 198 } 199 case Type::StructTyID: { 200 const StructType *DstST = cast<StructType>(DstTy); 201 const StructType *SrcST = cast<StructType>(SrcTy); 202 if (DstST->getNumContainedTypes() != SrcST->getNumContainedTypes()) 203 return true; 204 205 PATypeHolder ST(SrcST), DT(DstST); 206 for (unsigned i = 0, e = DstST->getNumContainedTypes(); i != e; ++i) { 207 const Type *SE = ST->getContainedType(i), *DE = DT->getContainedType(i); 208 if (SE != DE && RecursiveResolveTypesI(DE, SE, Pointers)) 209 return true; 210 } 211 return false; 212 } 213 case Type::ArrayTyID: { 214 const ArrayType *DAT = cast<ArrayType>(DstTy); 215 const ArrayType *SAT = cast<ArrayType>(SrcTy); 216 if (DAT->getNumElements() != SAT->getNumElements()) return true; 217 return RecursiveResolveTypesI(DAT->getElementType(), SAT->getElementType(), 218 Pointers); 219 } 220 case Type::VectorTyID: { 221 const VectorType *DVT = cast<VectorType>(DstTy); 222 const VectorType *SVT = cast<VectorType>(SrcTy); 223 if (DVT->getNumElements() != SVT->getNumElements()) return true; 224 return RecursiveResolveTypesI(DVT->getElementType(), SVT->getElementType(), 225 Pointers); 226 } 227 case Type::PointerTyID: { 228 const PointerType *DstPT = cast<PointerType>(DstTy); 229 const PointerType *SrcPT = cast<PointerType>(SrcTy); 230 231 if (DstPT->getAddressSpace() != SrcPT->getAddressSpace()) 232 return true; 233 234 // If this is a pointer type, check to see if we have already seen it. If 235 // so, we are in a recursive branch. Cut off the search now. We cannot use 236 // an associative container for this search, because the type pointers (keys 237 // in the container) change whenever types get resolved. 238 if (SrcPT->isAbstract()) 239 if (const Type *ExistingDestTy = Pointers.lookup(SrcPT)) 240 return ExistingDestTy != DstPT; 241 242 if (DstPT->isAbstract()) 243 if (const Type *ExistingSrcTy = Pointers.lookup(DstPT)) 244 return ExistingSrcTy != SrcPT; 245 // Otherwise, add the current pointers to the vector to stop recursion on 246 // this pair. 247 if (DstPT->isAbstract()) 248 Pointers.insert(DstPT, SrcPT); 249 if (SrcPT->isAbstract()) 250 Pointers.insert(SrcPT, DstPT); 251 252 return RecursiveResolveTypesI(DstPT->getElementType(), 253 SrcPT->getElementType(), Pointers); 254 } 255 } 256} 257 258static bool RecursiveResolveTypes(const Type *DestTy, const Type *SrcTy) { 259 LinkerTypeMap PointerTypes; 260 return RecursiveResolveTypesI(DestTy, SrcTy, PointerTypes); 261} 262 263 264// LinkTypes - Go through the symbol table of the Src module and see if any 265// types are named in the src module that are not named in the Dst module. 266// Make sure there are no type name conflicts. 267static bool LinkTypes(Module *Dest, const Module *Src, std::string *Err) { 268 TypeSymbolTable *DestST = &Dest->getTypeSymbolTable(); 269 const TypeSymbolTable *SrcST = &Src->getTypeSymbolTable(); 270 271 // Look for a type plane for Type's... 272 TypeSymbolTable::const_iterator TI = SrcST->begin(); 273 TypeSymbolTable::const_iterator TE = SrcST->end(); 274 if (TI == TE) return false; // No named types, do nothing. 275 276 // Some types cannot be resolved immediately because they depend on other 277 // types being resolved to each other first. This contains a list of types we 278 // are waiting to recheck. 279 std::vector<std::string> DelayedTypesToResolve; 280 281 for ( ; TI != TE; ++TI ) { 282 const std::string &Name = TI->first; 283 const Type *RHS = TI->second; 284 285 // Check to see if this type name is already in the dest module. 286 Type *Entry = DestST->lookup(Name); 287 288 // If the name is just in the source module, bring it over to the dest. 289 if (Entry == 0) { 290 if (!Name.empty()) 291 DestST->insert(Name, const_cast<Type*>(RHS)); 292 } else if (ResolveTypes(Entry, RHS)) { 293 // They look different, save the types 'till later to resolve. 294 DelayedTypesToResolve.push_back(Name); 295 } 296 } 297 298 // Iteratively resolve types while we can... 299 while (!DelayedTypesToResolve.empty()) { 300 // Loop over all of the types, attempting to resolve them if possible... 301 unsigned OldSize = DelayedTypesToResolve.size(); 302 303 // Try direct resolution by name... 304 for (unsigned i = 0; i != DelayedTypesToResolve.size(); ++i) { 305 const std::string &Name = DelayedTypesToResolve[i]; 306 Type *T1 = SrcST->lookup(Name); 307 Type *T2 = DestST->lookup(Name); 308 if (!ResolveTypes(T2, T1)) { 309 // We are making progress! 310 DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i); 311 --i; 312 } 313 } 314 315 // Did we not eliminate any types? 316 if (DelayedTypesToResolve.size() == OldSize) { 317 // Attempt to resolve subelements of types. This allows us to merge these 318 // two types: { int* } and { opaque* } 319 for (unsigned i = 0, e = DelayedTypesToResolve.size(); i != e; ++i) { 320 const std::string &Name = DelayedTypesToResolve[i]; 321 if (!RecursiveResolveTypes(SrcST->lookup(Name), DestST->lookup(Name))) { 322 // We are making progress! 323 DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i); 324 325 // Go back to the main loop, perhaps we can resolve directly by name 326 // now... 327 break; 328 } 329 } 330 331 // If we STILL cannot resolve the types, then there is something wrong. 332 if (DelayedTypesToResolve.size() == OldSize) { 333 // Remove the symbol name from the destination. 334 DelayedTypesToResolve.pop_back(); 335 } 336 } 337 } 338 339 340 return false; 341} 342 343#ifndef NDEBUG 344static void PrintMap(const std::map<const Value*, Value*> &M) { 345 for (std::map<const Value*, Value*>::const_iterator I = M.begin(), E =M.end(); 346 I != E; ++I) { 347 cerr << " Fr: " << (void*)I->first << " "; 348 I->first->dump(); 349 cerr << " To: " << (void*)I->second << " "; 350 I->second->dump(); 351 cerr << "\n"; 352 } 353} 354#endif 355 356 357// RemapOperand - Use ValueMap to convert constants from one module to another. 358static Value *RemapOperand(const Value *In, 359 std::map<const Value*, Value*> &ValueMap) { 360 std::map<const Value*,Value*>::const_iterator I = ValueMap.find(In); 361 if (I != ValueMap.end()) 362 return I->second; 363 364 // Check to see if it's a constant that we are interested in transforming. 365 Value *Result = 0; 366 if (const Constant *CPV = dyn_cast<Constant>(In)) { 367 if ((!isa<DerivedType>(CPV->getType()) && !isa<ConstantExpr>(CPV)) || 368 isa<ConstantInt>(CPV) || isa<ConstantAggregateZero>(CPV)) 369 return const_cast<Constant*>(CPV); // Simple constants stay identical. 370 371 if (const ConstantArray *CPA = dyn_cast<ConstantArray>(CPV)) { 372 std::vector<Constant*> Operands(CPA->getNumOperands()); 373 for (unsigned i = 0, e = CPA->getNumOperands(); i != e; ++i) 374 Operands[i] =cast<Constant>(RemapOperand(CPA->getOperand(i), ValueMap)); 375 Result = ConstantArray::get(cast<ArrayType>(CPA->getType()), Operands); 376 } else if (const ConstantStruct *CPS = dyn_cast<ConstantStruct>(CPV)) { 377 std::vector<Constant*> Operands(CPS->getNumOperands()); 378 for (unsigned i = 0, e = CPS->getNumOperands(); i != e; ++i) 379 Operands[i] =cast<Constant>(RemapOperand(CPS->getOperand(i), ValueMap)); 380 Result = ConstantStruct::get(cast<StructType>(CPS->getType()), Operands); 381 } else if (isa<ConstantPointerNull>(CPV) || isa<UndefValue>(CPV)) { 382 Result = const_cast<Constant*>(CPV); 383 } else if (const ConstantVector *CP = dyn_cast<ConstantVector>(CPV)) { 384 std::vector<Constant*> Operands(CP->getNumOperands()); 385 for (unsigned i = 0, e = CP->getNumOperands(); i != e; ++i) 386 Operands[i] = cast<Constant>(RemapOperand(CP->getOperand(i), ValueMap)); 387 Result = ConstantVector::get(Operands); 388 } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CPV)) { 389 std::vector<Constant*> Ops; 390 for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) 391 Ops.push_back(cast<Constant>(RemapOperand(CE->getOperand(i),ValueMap))); 392 Result = CE->getWithOperands(Ops); 393 } else { 394 assert(!isa<GlobalValue>(CPV) && "Unmapped global?"); 395 assert(0 && "Unknown type of derived type constant value!"); 396 } 397 } else if (isa<InlineAsm>(In)) { 398 Result = const_cast<Value*>(In); 399 } 400 401 // Cache the mapping in our local map structure 402 if (Result) { 403 ValueMap[In] = Result; 404 return Result; 405 } 406 407#ifndef NDEBUG 408 cerr << "LinkModules ValueMap: \n"; 409 PrintMap(ValueMap); 410 411 cerr << "Couldn't remap value: " << (void*)In << " " << *In << "\n"; 412 assert(0 && "Couldn't remap value!"); 413#endif 414 return 0; 415} 416 417/// ForceRenaming - The LLVM SymbolTable class autorenames globals that conflict 418/// in the symbol table. This is good for all clients except for us. Go 419/// through the trouble to force this back. 420static void ForceRenaming(GlobalValue *GV, const std::string &Name) { 421 assert(GV->getName() != Name && "Can't force rename to self"); 422 ValueSymbolTable &ST = GV->getParent()->getValueSymbolTable(); 423 424 // If there is a conflict, rename the conflict. 425 if (GlobalValue *ConflictGV = cast_or_null<GlobalValue>(ST.lookup(Name))) { 426 assert(ConflictGV->hasInternalLinkage() && 427 "Not conflicting with a static global, should link instead!"); 428 GV->takeName(ConflictGV); 429 ConflictGV->setName(Name); // This will cause ConflictGV to get renamed 430 assert(ConflictGV->getName() != Name && "ForceRenaming didn't work"); 431 } else { 432 GV->setName(Name); // Force the name back 433 } 434} 435 436/// CopyGVAttributes - copy additional attributes (those not needed to construct 437/// a GlobalValue) from the SrcGV to the DestGV. 438static void CopyGVAttributes(GlobalValue *DestGV, const GlobalValue *SrcGV) { 439 // Use the maximum alignment, rather than just copying the alignment of SrcGV. 440 unsigned Alignment = std::max(DestGV->getAlignment(), SrcGV->getAlignment()); 441 DestGV->copyAttributesFrom(SrcGV); 442 DestGV->setAlignment(Alignment); 443} 444 445/// GetLinkageResult - This analyzes the two global values and determines what 446/// the result will look like in the destination module. In particular, it 447/// computes the resultant linkage type, computes whether the global in the 448/// source should be copied over to the destination (replacing the existing 449/// one), and computes whether this linkage is an error or not. It also performs 450/// visibility checks: we cannot link together two symbols with different 451/// visibilities. 452static bool GetLinkageResult(GlobalValue *Dest, const GlobalValue *Src, 453 GlobalValue::LinkageTypes <, bool &LinkFromSrc, 454 std::string *Err) { 455 assert((!Dest || !Src->hasInternalLinkage()) && 456 "If Src has internal linkage, Dest shouldn't be set!"); 457 if (!Dest) { 458 // Linking something to nothing. 459 LinkFromSrc = true; 460 LT = Src->getLinkage(); 461 } else if (Src->isDeclaration()) { 462 // If Src is external or if both Src & Dest are external.. Just link the 463 // external globals, we aren't adding anything. 464 if (Src->hasDLLImportLinkage()) { 465 // If one of GVs has DLLImport linkage, result should be dllimport'ed. 466 if (Dest->isDeclaration()) { 467 LinkFromSrc = true; 468 LT = Src->getLinkage(); 469 } 470 } else if (Dest->hasExternalWeakLinkage()) { 471 //If the Dest is weak, use the source linkage 472 LinkFromSrc = true; 473 LT = Src->getLinkage(); 474 } else { 475 LinkFromSrc = false; 476 LT = Dest->getLinkage(); 477 } 478 } else if (Dest->isDeclaration() && !Dest->hasDLLImportLinkage()) { 479 // If Dest is external but Src is not: 480 LinkFromSrc = true; 481 LT = Src->getLinkage(); 482 } else if (Src->hasAppendingLinkage() || Dest->hasAppendingLinkage()) { 483 if (Src->getLinkage() != Dest->getLinkage()) 484 return Error(Err, "Linking globals named '" + Src->getName() + 485 "': can only link appending global with another appending global!"); 486 LinkFromSrc = true; // Special cased. 487 LT = Src->getLinkage(); 488 } else if (Src->isWeakForLinker()) { 489 // At this point we know that Dest has LinkOnce, External*, Weak, Common, 490 // or DLL* linkage. 491 if ((Dest->hasLinkOnceLinkage() && 492 (Src->hasWeakLinkage() || Src->hasCommonLinkage())) || 493 Dest->hasExternalWeakLinkage()) { 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// LinkGlobals - Loop through the global variables in the src module and merge 532// them into the dest module. 533static bool LinkGlobals(Module *Dest, const Module *Src, 534 std::map<const Value*, Value*> &ValueMap, 535 std::multimap<std::string, GlobalVariable *> &AppendingVars, 536 std::string *Err) { 537 ValueSymbolTable &DestSymTab = Dest->getValueSymbolTable(); 538 539 // Loop over all of the globals in the src module, mapping them over as we go 540 for (Module::const_global_iterator I = Src->global_begin(), 541 E = Src->global_end(); I != E; ++I) { 542 const GlobalVariable *SGV = I; 543 GlobalValue *DGV = 0; 544 545 // Check to see if may have to link the global with the global, alias or 546 // function. 547 if (SGV->hasName() && !SGV->hasInternalLinkage()) 548 DGV = cast_or_null<GlobalValue>(DestSymTab.lookup(SGV->getNameStart(), 549 SGV->getNameEnd())); 550 551 // If we found a global with the same name in the dest module, but it has 552 // internal linkage, we are really not doing any linkage here. 553 if (DGV && DGV->hasInternalLinkage()) 554 DGV = 0; 555 556 // If types don't agree due to opaque types, try to resolve them. 557 if (DGV && DGV->getType() != SGV->getType()) 558 RecursiveResolveTypes(SGV->getType(), DGV->getType()); 559 560 assert((SGV->hasInitializer() || SGV->hasExternalWeakLinkage() || 561 SGV->hasExternalLinkage() || SGV->hasDLLImportLinkage()) && 562 "Global must either be external or have an initializer!"); 563 564 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; 565 bool LinkFromSrc = false; 566 if (GetLinkageResult(DGV, SGV, NewLinkage, LinkFromSrc, Err)) 567 return true; 568 569 if (!DGV) { 570 // No linking to be performed, simply create an identical version of the 571 // symbol over in the dest module... the initializer will be filled in 572 // later by LinkGlobalInits. 573 GlobalVariable *NewDGV = 574 new GlobalVariable(SGV->getType()->getElementType(), 575 SGV->isConstant(), SGV->getLinkage(), /*init*/0, 576 SGV->getName(), Dest, false, 577 SGV->getType()->getAddressSpace()); 578 // Propagate alignment, visibility and section info. 579 CopyGVAttributes(NewDGV, SGV); 580 581 // If the LLVM runtime renamed the global, but it is an externally visible 582 // symbol, DGV must be an existing global with internal linkage. Rename 583 // it. 584 if (NewDGV->getName() != SGV->getName() && !NewDGV->hasInternalLinkage()) 585 ForceRenaming(NewDGV, SGV->getName()); 586 587 // Make sure to remember this mapping... 588 ValueMap[SGV] = NewDGV; 589 590 // Keep track that this is an appending variable. 591 if (SGV->hasAppendingLinkage()) 592 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV)); 593 } else if (DGV->hasAppendingLinkage()) { 594 // No linking is performed yet. Just insert a new copy of the global, and 595 // keep track of the fact that it is an appending variable in the 596 // AppendingVars map. The name is cleared out so that no linkage is 597 // performed. 598 GlobalVariable *NewDGV = 599 new GlobalVariable(SGV->getType()->getElementType(), 600 SGV->isConstant(), SGV->getLinkage(), /*init*/0, 601 "", Dest, false, 602 SGV->getType()->getAddressSpace()); 603 604 // Set alignment allowing CopyGVAttributes merge it with alignment of SGV. 605 NewDGV->setAlignment(DGV->getAlignment()); 606 // Propagate alignment, section and visibility info. 607 CopyGVAttributes(NewDGV, SGV); 608 609 // Make sure to remember this mapping... 610 ValueMap[SGV] = NewDGV; 611 612 // Keep track that this is an appending variable... 613 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV)); 614 } else if (GlobalAlias *DGA = dyn_cast<GlobalAlias>(DGV)) { 615 // SGV is global, but DGV is alias. The only valid mapping is when SGV is 616 // external declaration, which is effectively a no-op. Also make sure 617 // linkage calculation was correct. 618 if (!SGV->isDeclaration() || LinkFromSrc) 619 return Error(Err, "Global-Alias Collision on '" + SGV->getName() + 620 "': symbol multiple defined"); 621 622 // Make sure to remember this mapping. 623 ValueMap[SGV] = DGA; 624 } else if (LinkFromSrc) { 625 // If the types don't match, and if we are to link from the source, nuke 626 // DGV and create a new one of the appropriate type. Note that the thing 627 // we are replacing may be a function (if a prototype, weak, etc) or a 628 // global variable. 629 GlobalVariable *NewDGV = 630 new GlobalVariable(SGV->getType()->getElementType(), 631 SGV->isConstant(), SGV->getLinkage(), 632 /*init*/0, DGV->getName(), Dest, false, 633 SGV->getType()->getAddressSpace()); 634 635 // Propagate alignment, section, and visibility info. 636 CopyGVAttributes(NewDGV, SGV); 637 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDGV, DGV->getType())); 638 639 // DGV will conflict with NewDGV because they both had the same 640 // name. We must erase this now so ForceRenaming doesn't assert 641 // because DGV might not have internal linkage. 642 if (GlobalVariable *Var = dyn_cast<GlobalVariable>(DGV)) 643 Var->eraseFromParent(); 644 else 645 cast<Function>(DGV)->eraseFromParent(); 646 DGV = NewDGV; 647 648 // If the symbol table renamed the global, but it is an externally visible 649 // symbol, DGV must be an existing global with internal linkage. Rename. 650 if (NewDGV->getValueName() != SGV->getValueName() && 651 !NewDGV->hasInternalLinkage()) 652 ForceRenaming(NewDGV, SGV->getName()); 653 654 // Inherit const as appropriate 655 NewDGV->setConstant(SGV->isConstant()); 656 657 // Set calculated linkage 658 NewDGV->setLinkage(NewLinkage); 659 660 // Make sure to remember this mapping... 661 ValueMap[SGV] = ConstantExpr::getBitCast(NewDGV, SGV->getType()); 662 } else { 663 // Not "link from source", keep the one in the DestModule and remap the 664 // input onto it. 665 666 // Special case for const propagation. 667 if (GlobalVariable *DGVar = dyn_cast<GlobalVariable>(DGV)) 668 if (DGVar->isDeclaration() && SGV->isConstant() && !DGVar->isConstant()) 669 DGVar->setConstant(true); 670 671 // Set calculated linkage 672 DGV->setLinkage(NewLinkage); 673 674 // Make sure to remember this mapping... 675 ValueMap[SGV] = ConstantExpr::getBitCast(DGV, SGV->getType()); 676 } 677 } 678 return false; 679} 680 681static GlobalValue::LinkageTypes 682CalculateAliasLinkage(const GlobalValue *SGV, const GlobalValue *DGV) { 683 if (SGV->hasExternalLinkage() || DGV->hasExternalLinkage()) 684 return GlobalValue::ExternalLinkage; 685 else if (SGV->hasWeakLinkage() || DGV->hasWeakLinkage()) 686 return GlobalValue::WeakLinkage; 687 else { 688 assert(SGV->hasInternalLinkage() && DGV->hasInternalLinkage() && 689 "Unexpected linkage type"); 690 return GlobalValue::InternalLinkage; 691 } 692} 693 694// LinkAlias - Loop through the alias in the src module and link them into the 695// dest module. We're assuming, that all functions/global variables were already 696// linked in. 697static bool LinkAlias(Module *Dest, const Module *Src, 698 std::map<const Value*, Value*> &ValueMap, 699 std::string *Err) { 700 // Loop over all alias in the src module 701 for (Module::const_alias_iterator I = Src->alias_begin(), 702 E = Src->alias_end(); I != E; ++I) { 703 const GlobalAlias *SGA = I; 704 const GlobalValue *SAliasee = SGA->getAliasedGlobal(); 705 GlobalAlias *NewGA = NULL; 706 707 // Globals were already linked, thus we can just query ValueMap for variant 708 // of SAliasee in Dest. 709 std::map<const Value*,Value*>::const_iterator VMI = ValueMap.find(SAliasee); 710 assert(VMI != ValueMap.end() && "Aliasee not linked"); 711 GlobalValue* DAliasee = cast<GlobalValue>(VMI->second); 712 GlobalValue* DGV = NULL; 713 714 // Try to find something 'similar' to SGA in destination module. 715 if (!DGV && !SGA->hasInternalLinkage()) { 716 DGV = Dest->getNamedAlias(SGA->getName()); 717 718 // If types don't agree due to opaque types, try to resolve them. 719 if (DGV && DGV->getType() != SGA->getType()) 720 RecursiveResolveTypes(SGA->getType(), DGV->getType()); 721 } 722 723 if (!DGV && !SGA->hasInternalLinkage()) { 724 DGV = Dest->getGlobalVariable(SGA->getName()); 725 726 // If types don't agree due to opaque types, try to resolve them. 727 if (DGV && DGV->getType() != SGA->getType()) 728 RecursiveResolveTypes(SGA->getType(), DGV->getType()); 729 } 730 731 if (!DGV && !SGA->hasInternalLinkage()) { 732 DGV = Dest->getFunction(SGA->getName()); 733 734 // If types don't agree due to opaque types, try to resolve them. 735 if (DGV && DGV->getType() != SGA->getType()) 736 RecursiveResolveTypes(SGA->getType(), DGV->getType()); 737 } 738 739 // No linking to be performed on internal stuff. 740 if (DGV && DGV->hasInternalLinkage()) 741 DGV = NULL; 742 743 if (GlobalAlias *DGA = dyn_cast_or_null<GlobalAlias>(DGV)) { 744 // Types are known to be the same, check whether aliasees equal. As 745 // globals are already linked we just need query ValueMap to find the 746 // mapping. 747 if (DAliasee == DGA->getAliasedGlobal()) { 748 // This is just two copies of the same alias. Propagate linkage, if 749 // necessary. 750 DGA->setLinkage(CalculateAliasLinkage(SGA, DGA)); 751 752 NewGA = DGA; 753 // Proceed to 'common' steps 754 } else 755 return Error(Err, "Alias Collision on '" + SGA->getName()+ 756 "': aliases have different aliasees"); 757 } else if (GlobalVariable *DGVar = dyn_cast_or_null<GlobalVariable>(DGV)) { 758 // The only allowed way is to link alias with external declaration or weak 759 // symbol.. 760 if (DGVar->isDeclaration() || DGVar->isWeakForLinker()) { 761 // But only if aliasee is global too... 762 if (!isa<GlobalVariable>(DAliasee)) 763 return Error(Err, "Global-Alias Collision on '" + SGA->getName() + 764 "': aliasee is not global variable"); 765 766 NewGA = new GlobalAlias(SGA->getType(), SGA->getLinkage(), 767 SGA->getName(), DAliasee, Dest); 768 CopyGVAttributes(NewGA, SGA); 769 770 // Any uses of DGV need to change to NewGA, with cast, if needed. 771 if (SGA->getType() != DGVar->getType()) 772 DGVar->replaceAllUsesWith(ConstantExpr::getBitCast(NewGA, 773 DGVar->getType())); 774 else 775 DGVar->replaceAllUsesWith(NewGA); 776 777 // DGVar will conflict with NewGA because they both had the same 778 // name. We must erase this now so ForceRenaming doesn't assert 779 // because DGV might not have internal linkage. 780 DGVar->eraseFromParent(); 781 782 // Proceed to 'common' steps 783 } else 784 return Error(Err, "Global-Alias Collision on '" + SGA->getName() + 785 "': symbol multiple defined"); 786 } else if (Function *DF = dyn_cast_or_null<Function>(DGV)) { 787 // The only allowed way is to link alias with external declaration or weak 788 // symbol... 789 if (DF->isDeclaration() || DF->isWeakForLinker()) { 790 // But only if aliasee is function too... 791 if (!isa<Function>(DAliasee)) 792 return Error(Err, "Function-Alias Collision on '" + SGA->getName() + 793 "': aliasee is not function"); 794 795 NewGA = new GlobalAlias(SGA->getType(), SGA->getLinkage(), 796 SGA->getName(), DAliasee, Dest); 797 CopyGVAttributes(NewGA, SGA); 798 799 // Any uses of DF need to change to NewGA, with cast, if needed. 800 if (SGA->getType() != DF->getType()) 801 DF->replaceAllUsesWith(ConstantExpr::getBitCast(NewGA, 802 DF->getType())); 803 else 804 DF->replaceAllUsesWith(NewGA); 805 806 // DF will conflict with NewGA because they both had the same 807 // name. We must erase this now so ForceRenaming doesn't assert 808 // because DF might not have internal linkage. 809 DF->eraseFromParent(); 810 811 // Proceed to 'common' steps 812 } else 813 return Error(Err, "Function-Alias Collision on '" + SGA->getName() + 814 "': symbol multiple defined"); 815 } else { 816 // No linking to be performed, simply create an identical version of the 817 // alias over in the dest module... 818 819 NewGA = new GlobalAlias(SGA->getType(), SGA->getLinkage(), 820 SGA->getName(), DAliasee, Dest); 821 CopyGVAttributes(NewGA, SGA); 822 823 // Proceed to 'common' steps 824 } 825 826 assert(NewGA && "No alias was created in destination module!"); 827 828 // If the symbol table renamed the alias, but it is an externally visible 829 // symbol, DGA must be an global value with internal linkage. Rename it. 830 if (NewGA->getName() != SGA->getName() && 831 !NewGA->hasInternalLinkage()) 832 ForceRenaming(NewGA, SGA->getName()); 833 834 // Remember this mapping so uses in the source module get remapped 835 // later by RemapOperand. 836 ValueMap[SGA] = NewGA; 837 } 838 839 return false; 840} 841 842 843// LinkGlobalInits - Update the initializers in the Dest module now that all 844// globals that may be referenced are in Dest. 845static bool LinkGlobalInits(Module *Dest, const Module *Src, 846 std::map<const Value*, Value*> &ValueMap, 847 std::string *Err) { 848 // Loop over all of the globals in the src module, mapping them over as we go 849 for (Module::const_global_iterator I = Src->global_begin(), 850 E = Src->global_end(); I != E; ++I) { 851 const GlobalVariable *SGV = I; 852 853 if (SGV->hasInitializer()) { // Only process initialized GV's 854 // Figure out what the initializer looks like in the dest module... 855 Constant *SInit = 856 cast<Constant>(RemapOperand(SGV->getInitializer(), ValueMap)); 857 858 GlobalVariable *DGV = 859 cast<GlobalVariable>(ValueMap[SGV]->stripPointerCasts()); 860 if (DGV->hasInitializer()) { 861 if (SGV->hasExternalLinkage()) { 862 if (DGV->getInitializer() != SInit) 863 return Error(Err, "Global Variable Collision on '" + SGV->getName() + 864 "': global variables have different initializers"); 865 } else if (DGV->isWeakForLinker()) { 866 // Nothing is required, mapped values will take the new global 867 // automatically. 868 } else if (SGV->isWeakForLinker()) { 869 // Nothing is required, mapped values will take the new global 870 // automatically. 871 } else if (DGV->hasAppendingLinkage()) { 872 assert(0 && "Appending linkage unimplemented!"); 873 } else { 874 assert(0 && "Unknown linkage!"); 875 } 876 } else { 877 // Copy the initializer over now... 878 DGV->setInitializer(SInit); 879 } 880 } 881 } 882 return false; 883} 884 885// LinkFunctionProtos - Link the functions together between the two modules, 886// without doing function bodies... this just adds external function prototypes 887// to the Dest function... 888// 889static bool LinkFunctionProtos(Module *Dest, const Module *Src, 890 std::map<const Value*, Value*> &ValueMap, 891 std::string *Err) { 892 ValueSymbolTable &DestSymTab = Dest->getValueSymbolTable(); 893 894 // Loop over all of the functions in the src module, mapping them over 895 for (Module::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) { 896 const Function *SF = I; // SrcFunction 897 GlobalValue *DGV = 0; 898 Value *MappedDF; 899 900 // Check to see if may have to link the function with the global, alias or 901 // function. 902 if (SF->hasName() && !SF->hasInternalLinkage()) 903 DGV = cast_or_null<GlobalValue>(DestSymTab.lookup(SF->getNameStart(), 904 SF->getNameEnd())); 905 906 // If we found a global with the same name in the dest module, but it has 907 // internal linkage, we are really not doing any linkage here. 908 if (DGV && DGV->hasInternalLinkage()) 909 DGV = 0; 910 911 // If types don't agree due to opaque types, try to resolve them. 912 if (DGV && DGV->getType() != SF->getType()) 913 RecursiveResolveTypes(SF->getType(), DGV->getType()); 914 915 // If there is no linkage to be performed, just bring over SF without 916 // modifying it. 917 if (DGV == 0) { 918 // Function does not already exist, simply insert an function signature 919 // identical to SF into the dest module. 920 Function *NewDF = Function::Create(SF->getFunctionType(), 921 SF->getLinkage(), 922 SF->getName(), Dest); 923 CopyGVAttributes(NewDF, SF); 924 925 // If the LLVM runtime renamed the function, but it is an externally 926 // visible symbol, DF must be an existing function with internal linkage. 927 // Rename it. 928 if (!NewDF->hasInternalLinkage() && NewDF->getName() != SF->getName()) 929 ForceRenaming(NewDF, SF->getName()); 930 931 // ... and remember this mapping... 932 ValueMap[SF] = NewDF; 933 continue; 934 } else if (GlobalAlias *DGA = dyn_cast<GlobalAlias>(DGV)) { 935 // SF is function, but DF is alias. 936 // The only valid mappings are: 937 // - SF is external declaration, which is effectively a no-op. 938 // - SF is weak, when we just need to throw SF out. 939 if (!SF->isDeclaration() && !SF->isWeakForLinker()) 940 return Error(Err, "Function-Alias Collision on '" + SF->getName() + 941 "': symbol multiple defined"); 942 943 // Make sure to remember this mapping... 944 ValueMap[SF] = ConstantExpr::getBitCast(DGA, SF->getType()); 945 continue; 946 } 947 948 Function* DF = cast<Function>(DGV); 949 // If types don't agree because of opaque, try to resolve them. 950 if (SF->getType() != DF->getType()) 951 RecursiveResolveTypes(SF->getType(), DF->getType()); 952 953 // Check visibility, merging if a definition overrides a prototype. 954 if (SF->getVisibility() != DF->getVisibility()) { 955 // If one is a prototype, ignore its visibility. Prototypes are always 956 // overridden by the definition. 957 if (!SF->isDeclaration() && !DF->isDeclaration()) 958 return Error(Err, "Linking functions named '" + SF->getName() + 959 "': symbols have different visibilities!"); 960 961 // Otherwise, replace the visibility of DF if DF is a prototype. 962 if (DF->isDeclaration()) 963 DF->setVisibility(SF->getVisibility()); 964 } 965 966 if (DF->getType() != SF->getType()) { 967 if (DF->isDeclaration() && !SF->isDeclaration()) { 968 // We have a definition of the same name but different type in the 969 // source module. Copy the prototype to the destination and replace 970 // uses of the destination's prototype with the new prototype. 971 Function *NewDF = Function::Create(SF->getFunctionType(), 972 SF->getLinkage(), 973 SF->getName(), Dest); 974 CopyGVAttributes(NewDF, SF); 975 976 // Any uses of DF need to change to NewDF, with cast 977 DF->replaceAllUsesWith(ConstantExpr::getBitCast(NewDF, DF->getType())); 978 979 // DF will conflict with NewDF because they both had the same. We must 980 // erase this now so ForceRenaming doesn't assert because DF might 981 // not have internal linkage. 982 DF->eraseFromParent(); 983 984 // If the symbol table renamed the function, but it is an externally 985 // visible symbol, DF must be an existing function with internal 986 // linkage. Rename it. 987 if (NewDF->getName() != SF->getName() && !NewDF->hasInternalLinkage()) 988 ForceRenaming(NewDF, SF->getName()); 989 990 // Remember this mapping so uses in the source module get remapped 991 // later by RemapOperand. 992 ValueMap[SF] = NewDF; 993 continue; 994 } else { 995 // We have two functions of the same name but different type. Any use 996 // of the source must be mapped to the destination, with a cast. 997 MappedDF = ConstantExpr::getBitCast(DF, SF->getType()); 998 } 999 } else { 1000 MappedDF = DF; 1001 } 1002 1003 if (SF->isDeclaration()) { 1004 // If SF is a declaration or if both SF & DF are declarations, just link 1005 // the declarations, we aren't adding anything. 1006 if (SF->hasDLLImportLinkage()) { 1007 if (DF->isDeclaration()) { 1008 ValueMap[SF] = MappedDF; 1009 DF->setLinkage(SF->getLinkage()); 1010 } 1011 } else { 1012 ValueMap[SF] = MappedDF; 1013 } 1014 continue; 1015 } 1016 1017 // If DF is external but SF is not, link the external functions, update 1018 // linkage qualifiers. 1019 if (DF->isDeclaration() && !DF->hasDLLImportLinkage()) { 1020 ValueMap.insert(std::make_pair(SF, MappedDF)); 1021 DF->setLinkage(SF->getLinkage()); 1022 continue; 1023 } 1024 1025 // At this point we know that DF has LinkOnce, Weak, or External* linkage. 1026 if (SF->isWeakForLinker()) { 1027 ValueMap[SF] = MappedDF; 1028 1029 // Linkonce+Weak = Weak 1030 // *+External Weak = * 1031 if ((DF->hasLinkOnceLinkage() && 1032 (SF->hasWeakLinkage() || SF->hasCommonLinkage())) || 1033 DF->hasExternalWeakLinkage()) 1034 DF->setLinkage(SF->getLinkage()); 1035 continue; 1036 } 1037 1038 if (DF->isWeakForLinker()) { 1039 // At this point we know that SF has LinkOnce or External* linkage. 1040 ValueMap[SF] = MappedDF; 1041 1042 // If the source function has stronger linkage than the destination, 1043 // its body and linkage should override ours. 1044 if (!SF->hasLinkOnceLinkage() && !SF->hasExternalWeakLinkage()) { 1045 // Don't inherit linkonce & external weak linkage. 1046 DF->setLinkage(SF->getLinkage()); 1047 DF->deleteBody(); 1048 } 1049 continue; 1050 } 1051 1052 if (SF->getLinkage() != DF->getLinkage()) 1053 return Error(Err, "Functions named '" + SF->getName() + 1054 "' have different linkage specifiers!"); 1055 1056 // The function is defined identically in both modules! 1057 if (SF->hasExternalLinkage()) 1058 return Error(Err, "Function '" + 1059 ToStr(SF->getFunctionType(), Src) + "':\"" + 1060 SF->getName() + "\" - Function is already defined!"); 1061 assert(0 && "Unknown linkage configuration found!"); 1062 } 1063 return false; 1064} 1065 1066// LinkFunctionBody - Copy the source function over into the dest function and 1067// fix up references to values. At this point we know that Dest is an external 1068// function, and that Src is not. 1069static bool LinkFunctionBody(Function *Dest, Function *Src, 1070 std::map<const Value*, Value*> &ValueMap, 1071 std::string *Err) { 1072 assert(Src && Dest && Dest->isDeclaration() && !Src->isDeclaration()); 1073 1074 // Go through and convert function arguments over, remembering the mapping. 1075 Function::arg_iterator DI = Dest->arg_begin(); 1076 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end(); 1077 I != E; ++I, ++DI) { 1078 DI->setName(I->getName()); // Copy the name information over... 1079 1080 // Add a mapping to our local map 1081 ValueMap[I] = DI; 1082 } 1083 1084 // Splice the body of the source function into the dest function. 1085 Dest->getBasicBlockList().splice(Dest->end(), Src->getBasicBlockList()); 1086 1087 // At this point, all of the instructions and values of the function are now 1088 // copied over. The only problem is that they are still referencing values in 1089 // the Source function as operands. Loop through all of the operands of the 1090 // functions and patch them up to point to the local versions... 1091 // 1092 for (Function::iterator BB = Dest->begin(), BE = Dest->end(); BB != BE; ++BB) 1093 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) 1094 for (Instruction::op_iterator OI = I->op_begin(), OE = I->op_end(); 1095 OI != OE; ++OI) 1096 if (!isa<Instruction>(*OI) && !isa<BasicBlock>(*OI)) 1097 *OI = RemapOperand(*OI, ValueMap); 1098 1099 // There is no need to map the arguments anymore. 1100 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end(); 1101 I != E; ++I) 1102 ValueMap.erase(I); 1103 1104 return false; 1105} 1106 1107 1108// LinkFunctionBodies - Link in the function bodies that are defined in the 1109// source module into the DestModule. This consists basically of copying the 1110// function over and fixing up references to values. 1111static bool LinkFunctionBodies(Module *Dest, Module *Src, 1112 std::map<const Value*, Value*> &ValueMap, 1113 std::string *Err) { 1114 1115 // Loop over all of the functions in the src module, mapping them over as we 1116 // go 1117 for (Module::iterator SF = Src->begin(), E = Src->end(); SF != E; ++SF) { 1118 if (!SF->isDeclaration()) { // No body if function is external 1119 Function *DF = dyn_cast<Function>(ValueMap[SF]); // Destination function 1120 1121 // DF not external SF external? 1122 if (DF && DF->isDeclaration()) 1123 // Only provide the function body if there isn't one already. 1124 if (LinkFunctionBody(DF, SF, ValueMap, Err)) 1125 return true; 1126 } 1127 } 1128 return false; 1129} 1130 1131// LinkAppendingVars - If there were any appending global variables, link them 1132// together now. Return true on error. 1133static bool LinkAppendingVars(Module *M, 1134 std::multimap<std::string, GlobalVariable *> &AppendingVars, 1135 std::string *ErrorMsg) { 1136 if (AppendingVars.empty()) return false; // Nothing to do. 1137 1138 // Loop over the multimap of appending vars, processing any variables with the 1139 // same name, forming a new appending global variable with both of the 1140 // initializers merged together, then rewrite references to the old variables 1141 // and delete them. 1142 std::vector<Constant*> Inits; 1143 while (AppendingVars.size() > 1) { 1144 // Get the first two elements in the map... 1145 std::multimap<std::string, 1146 GlobalVariable*>::iterator Second = AppendingVars.begin(), First=Second++; 1147 1148 // If the first two elements are for different names, there is no pair... 1149 // Otherwise there is a pair, so link them together... 1150 if (First->first == Second->first) { 1151 GlobalVariable *G1 = First->second, *G2 = Second->second; 1152 const ArrayType *T1 = cast<ArrayType>(G1->getType()->getElementType()); 1153 const ArrayType *T2 = cast<ArrayType>(G2->getType()->getElementType()); 1154 1155 // Check to see that they two arrays agree on type... 1156 if (T1->getElementType() != T2->getElementType()) 1157 return Error(ErrorMsg, 1158 "Appending variables with different element types need to be linked!"); 1159 if (G1->isConstant() != G2->isConstant()) 1160 return Error(ErrorMsg, 1161 "Appending variables linked with different const'ness!"); 1162 1163 if (G1->getAlignment() != G2->getAlignment()) 1164 return Error(ErrorMsg, 1165 "Appending variables with different alignment need to be linked!"); 1166 1167 if (G1->getVisibility() != G2->getVisibility()) 1168 return Error(ErrorMsg, 1169 "Appending variables with different visibility need to be linked!"); 1170 1171 if (G1->getSection() != G2->getSection()) 1172 return Error(ErrorMsg, 1173 "Appending variables with different section name need to be linked!"); 1174 1175 unsigned NewSize = T1->getNumElements() + T2->getNumElements(); 1176 ArrayType *NewType = ArrayType::get(T1->getElementType(), NewSize); 1177 1178 G1->setName(""); // Clear G1's name in case of a conflict! 1179 1180 // Create the new global variable... 1181 GlobalVariable *NG = 1182 new GlobalVariable(NewType, G1->isConstant(), G1->getLinkage(), 1183 /*init*/0, First->first, M, G1->isThreadLocal(), 1184 G1->getType()->getAddressSpace()); 1185 1186 // Propagate alignment, visibility and section info. 1187 CopyGVAttributes(NG, G1); 1188 1189 // Merge the initializer... 1190 Inits.reserve(NewSize); 1191 if (ConstantArray *I = dyn_cast<ConstantArray>(G1->getInitializer())) { 1192 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i) 1193 Inits.push_back(I->getOperand(i)); 1194 } else { 1195 assert(isa<ConstantAggregateZero>(G1->getInitializer())); 1196 Constant *CV = Constant::getNullValue(T1->getElementType()); 1197 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i) 1198 Inits.push_back(CV); 1199 } 1200 if (ConstantArray *I = dyn_cast<ConstantArray>(G2->getInitializer())) { 1201 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i) 1202 Inits.push_back(I->getOperand(i)); 1203 } else { 1204 assert(isa<ConstantAggregateZero>(G2->getInitializer())); 1205 Constant *CV = Constant::getNullValue(T2->getElementType()); 1206 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i) 1207 Inits.push_back(CV); 1208 } 1209 NG->setInitializer(ConstantArray::get(NewType, Inits)); 1210 Inits.clear(); 1211 1212 // Replace any uses of the two global variables with uses of the new 1213 // global... 1214 1215 // FIXME: This should rewrite simple/straight-forward uses such as 1216 // getelementptr instructions to not use the Cast! 1217 G1->replaceAllUsesWith(ConstantExpr::getBitCast(NG, G1->getType())); 1218 G2->replaceAllUsesWith(ConstantExpr::getBitCast(NG, G2->getType())); 1219 1220 // Remove the two globals from the module now... 1221 M->getGlobalList().erase(G1); 1222 M->getGlobalList().erase(G2); 1223 1224 // Put the new global into the AppendingVars map so that we can handle 1225 // linking of more than two vars... 1226 Second->second = NG; 1227 } 1228 AppendingVars.erase(First); 1229 } 1230 1231 return false; 1232} 1233 1234static bool ResolveAliases(Module *Dest) { 1235 for (Module::alias_iterator I = Dest->alias_begin(), E = Dest->alias_end(); 1236 I != E; ++I) 1237 if (const GlobalValue *GV = I->resolveAliasedGlobal()) 1238 if (!GV->isDeclaration()) 1239 I->replaceAllUsesWith(const_cast<GlobalValue*>(GV)); 1240 1241 return false; 1242} 1243 1244// LinkModules - This function links two modules together, with the resulting 1245// left module modified to be the composite of the two input modules. If an 1246// error occurs, true is returned and ErrorMsg (if not null) is set to indicate 1247// the problem. Upon failure, the Dest module could be in a modified state, and 1248// shouldn't be relied on to be consistent. 1249bool 1250Linker::LinkModules(Module *Dest, Module *Src, std::string *ErrorMsg) { 1251 assert(Dest != 0 && "Invalid Destination module"); 1252 assert(Src != 0 && "Invalid Source Module"); 1253 1254 if (Dest->getDataLayout().empty()) { 1255 if (!Src->getDataLayout().empty()) { 1256 Dest->setDataLayout(Src->getDataLayout()); 1257 } else { 1258 std::string DataLayout; 1259 1260 if (Dest->getEndianness() == Module::AnyEndianness) { 1261 if (Src->getEndianness() == Module::BigEndian) 1262 DataLayout.append("E"); 1263 else if (Src->getEndianness() == Module::LittleEndian) 1264 DataLayout.append("e"); 1265 } 1266 1267 if (Dest->getPointerSize() == Module::AnyPointerSize) { 1268 if (Src->getPointerSize() == Module::Pointer64) 1269 DataLayout.append(DataLayout.length() == 0 ? "p:64:64" : "-p:64:64"); 1270 else if (Src->getPointerSize() == Module::Pointer32) 1271 DataLayout.append(DataLayout.length() == 0 ? "p:32:32" : "-p:32:32"); 1272 } 1273 Dest->setDataLayout(DataLayout); 1274 } 1275 } 1276 1277 // Copy the target triple from the source to dest if the dest's is empty. 1278 if (Dest->getTargetTriple().empty() && !Src->getTargetTriple().empty()) 1279 Dest->setTargetTriple(Src->getTargetTriple()); 1280 1281 if (!Src->getDataLayout().empty() && !Dest->getDataLayout().empty() && 1282 Src->getDataLayout() != Dest->getDataLayout()) 1283 cerr << "WARNING: Linking two modules of different data layouts!\n"; 1284 if (!Src->getTargetTriple().empty() && 1285 Dest->getTargetTriple() != Src->getTargetTriple()) 1286 cerr << "WARNING: Linking two modules of different target triples!\n"; 1287 1288 // Append the module inline asm string. 1289 if (!Src->getModuleInlineAsm().empty()) { 1290 if (Dest->getModuleInlineAsm().empty()) 1291 Dest->setModuleInlineAsm(Src->getModuleInlineAsm()); 1292 else 1293 Dest->setModuleInlineAsm(Dest->getModuleInlineAsm()+"\n"+ 1294 Src->getModuleInlineAsm()); 1295 } 1296 1297 // Update the destination module's dependent libraries list with the libraries 1298 // from the source module. There's no opportunity for duplicates here as the 1299 // Module ensures that duplicate insertions are discarded. 1300 for (Module::lib_iterator SI = Src->lib_begin(), SE = Src->lib_end(); 1301 SI != SE; ++SI) 1302 Dest->addLibrary(*SI); 1303 1304 // LinkTypes - Go through the symbol table of the Src module and see if any 1305 // types are named in the src module that are not named in the Dst module. 1306 // Make sure there are no type name conflicts. 1307 if (LinkTypes(Dest, Src, ErrorMsg)) 1308 return true; 1309 1310 // ValueMap - Mapping of values from what they used to be in Src, to what they 1311 // are now in Dest. 1312 std::map<const Value*, Value*> ValueMap; 1313 1314 // AppendingVars - Keep track of global variables in the destination module 1315 // with appending linkage. After the module is linked together, they are 1316 // appended and the module is rewritten. 1317 std::multimap<std::string, GlobalVariable *> AppendingVars; 1318 for (Module::global_iterator I = Dest->global_begin(), E = Dest->global_end(); 1319 I != E; ++I) { 1320 // Add all of the appending globals already in the Dest module to 1321 // AppendingVars. 1322 if (I->hasAppendingLinkage()) 1323 AppendingVars.insert(std::make_pair(I->getName(), I)); 1324 } 1325 1326 // Insert all of the globals in src into the Dest module... without linking 1327 // initializers (which could refer to functions not yet mapped over). 1328 if (LinkGlobals(Dest, Src, ValueMap, AppendingVars, ErrorMsg)) 1329 return true; 1330 1331 // Link the functions together between the two modules, without doing function 1332 // bodies... this just adds external function prototypes to the Dest 1333 // function... We do this so that when we begin processing function bodies, 1334 // all of the global values that may be referenced are available in our 1335 // ValueMap. 1336 if (LinkFunctionProtos(Dest, Src, ValueMap, ErrorMsg)) 1337 return true; 1338 1339 // If there were any alias, link them now. We really need to do this now, 1340 // because all of the aliases that may be referenced need to be available in 1341 // ValueMap 1342 if (LinkAlias(Dest, Src, ValueMap, ErrorMsg)) return true; 1343 1344 // Update the initializers in the Dest module now that all globals that may 1345 // be referenced are in Dest. 1346 if (LinkGlobalInits(Dest, Src, ValueMap, ErrorMsg)) return true; 1347 1348 // Link in the function bodies that are defined in the source module into the 1349 // DestModule. This consists basically of copying the function over and 1350 // fixing up references to values. 1351 if (LinkFunctionBodies(Dest, Src, ValueMap, ErrorMsg)) return true; 1352 1353 // If there were any appending global variables, link them together now. 1354 if (LinkAppendingVars(Dest, AppendingVars, ErrorMsg)) return true; 1355 1356 // Resolve all uses of aliases with aliasees 1357 if (ResolveAliases(Dest)) return true; 1358 1359 // If the source library's module id is in the dependent library list of the 1360 // destination library, remove it since that module is now linked in. 1361 sys::Path modId; 1362 modId.set(Src->getModuleIdentifier()); 1363 if (!modId.isEmpty()) 1364 Dest->removeLibrary(modId.getBasename()); 1365 1366 return false; 1367} 1368 1369// vim: sw=2 1370