LinkModules.cpp revision 5df3186f598163258fabf3448d9372843804d1ab
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// Function: ResolveTypes() 41// 42// Description: 43// Attempt to link the two specified types together. 44// 45// Inputs: 46// DestTy - The type to which we wish to resolve. 47// SrcTy - The original type which we want to resolve. 48// 49// Outputs: 50// DestST - The symbol table in which the new type should be placed. 51// 52// Return value: 53// true - There is an error and the types cannot yet be linked. 54// false - No errors. 55// 56static bool ResolveTypes(const Type *DestTy, const Type *SrcTy) { 57 if (DestTy == SrcTy) return false; // If already equal, noop 58 assert(DestTy && SrcTy && "Can't handle null types"); 59 60 if (const OpaqueType *OT = dyn_cast<OpaqueType>(DestTy)) { 61 // Type _is_ in module, just opaque... 62 const_cast<OpaqueType*>(OT)->refineAbstractTypeTo(SrcTy); 63 } else if (const OpaqueType *OT = dyn_cast<OpaqueType>(SrcTy)) { 64 const_cast<OpaqueType*>(OT)->refineAbstractTypeTo(DestTy); 65 } else { 66 return true; // Cannot link types... not-equal and neither is opaque. 67 } 68 return false; 69} 70 71/// LinkerTypeMap - This implements a map of types that is stable 72/// even if types are resolved/refined to other types. This is not a general 73/// purpose map, it is specific to the linker's use. 74namespace { 75class LinkerTypeMap : public AbstractTypeUser { 76 typedef DenseMap<const Type*, PATypeHolder> TheMapTy; 77 TheMapTy TheMap; 78 79 LinkerTypeMap(const LinkerTypeMap&); // DO NOT IMPLEMENT 80 void operator=(const LinkerTypeMap&); // DO NOT IMPLEMENT 81public: 82 LinkerTypeMap() {} 83 ~LinkerTypeMap() { 84 for (DenseMap<const Type*, PATypeHolder>::iterator I = TheMap.begin(), 85 E = TheMap.end(); I != E; ++I) 86 I->first->removeAbstractTypeUser(this); 87 } 88 89 /// lookup - Return the value for the specified type or null if it doesn't 90 /// exist. 91 const Type *lookup(const Type *Ty) const { 92 TheMapTy::const_iterator I = TheMap.find(Ty); 93 if (I != TheMap.end()) return I->second; 94 return 0; 95 } 96 97 /// erase - Remove the specified type, returning true if it was in the set. 98 bool erase(const Type *Ty) { 99 if (!TheMap.erase(Ty)) 100 return false; 101 if (Ty->isAbstract()) 102 Ty->removeAbstractTypeUser(this); 103 return true; 104 } 105 106 /// insert - This returns true if the pointer was new to the set, false if it 107 /// was already in the set. 108 bool insert(const Type *Src, const Type *Dst) { 109 if (!TheMap.insert(std::make_pair(Src, PATypeHolder(Dst))).second) 110 return false; // Already in map. 111 if (Src->isAbstract()) 112 Src->addAbstractTypeUser(this); 113 return true; 114 } 115 116protected: 117 /// refineAbstractType - The callback method invoked when an abstract type is 118 /// resolved to another type. An object must override this method to update 119 /// its internal state to reference NewType instead of OldType. 120 /// 121 virtual void refineAbstractType(const DerivedType *OldTy, 122 const Type *NewTy) { 123 TheMapTy::iterator I = TheMap.find(OldTy); 124 const Type *DstTy = I->second; 125 126 TheMap.erase(I); 127 if (OldTy->isAbstract()) 128 OldTy->removeAbstractTypeUser(this); 129 130 // Don't reinsert into the map if the key is concrete now. 131 if (NewTy->isAbstract()) 132 insert(NewTy, DstTy); 133 } 134 135 /// The other case which AbstractTypeUsers must be aware of is when a type 136 /// makes the transition from being abstract (where it has clients on it's 137 /// AbstractTypeUsers list) to concrete (where it does not). This method 138 /// notifies ATU's when this occurs for a type. 139 virtual void typeBecameConcrete(const DerivedType *AbsTy) { 140 TheMap.erase(AbsTy); 141 AbsTy->removeAbstractTypeUser(this); 142 } 143 144 // for debugging... 145 virtual void dump() const { 146 cerr << "AbstractTypeSet!\n"; 147 } 148}; 149} 150 151 152// RecursiveResolveTypes - This is just like ResolveTypes, except that it 153// recurses down into derived types, merging the used types if the parent types 154// are compatible. 155static bool RecursiveResolveTypesI(const Type *DstTy, const Type *SrcTy, 156 LinkerTypeMap &Pointers) { 157 if (DstTy == SrcTy) return false; // If already equal, noop 158 159 // If we found our opaque type, resolve it now! 160 if (isa<OpaqueType>(DstTy) || isa<OpaqueType>(SrcTy)) 161 return ResolveTypes(DstTy, SrcTy); 162 163 // Two types cannot be resolved together if they are of different primitive 164 // type. For example, we cannot resolve an int to a float. 165 if (DstTy->getTypeID() != SrcTy->getTypeID()) return true; 166 167 // If neither type is abstract, then they really are just different types. 168 if (!DstTy->isAbstract() && !SrcTy->isAbstract()) 169 return true; 170 171 // Otherwise, resolve the used type used by this derived type... 172 switch (DstTy->getTypeID()) { 173 default: 174 return true; 175 case Type::FunctionTyID: { 176 const FunctionType *DstFT = cast<FunctionType>(DstTy); 177 const FunctionType *SrcFT = cast<FunctionType>(SrcTy); 178 if (DstFT->isVarArg() != SrcFT->isVarArg() || 179 DstFT->getNumContainedTypes() != SrcFT->getNumContainedTypes()) 180 return true; 181 182 // Use TypeHolder's so recursive resolution won't break us. 183 PATypeHolder ST(SrcFT), DT(DstFT); 184 for (unsigned i = 0, e = DstFT->getNumContainedTypes(); i != e; ++i) { 185 const Type *SE = ST->getContainedType(i), *DE = DT->getContainedType(i); 186 if (SE != DE && RecursiveResolveTypesI(DE, SE, Pointers)) 187 return true; 188 } 189 return false; 190 } 191 case Type::StructTyID: { 192 const StructType *DstST = cast<StructType>(DstTy); 193 const StructType *SrcST = cast<StructType>(SrcTy); 194 if (DstST->getNumContainedTypes() != SrcST->getNumContainedTypes()) 195 return true; 196 197 PATypeHolder ST(SrcST), DT(DstST); 198 for (unsigned i = 0, e = DstST->getNumContainedTypes(); i != e; ++i) { 199 const Type *SE = ST->getContainedType(i), *DE = DT->getContainedType(i); 200 if (SE != DE && RecursiveResolveTypesI(DE, SE, Pointers)) 201 return true; 202 } 203 return false; 204 } 205 case Type::ArrayTyID: { 206 const ArrayType *DAT = cast<ArrayType>(DstTy); 207 const ArrayType *SAT = cast<ArrayType>(SrcTy); 208 if (DAT->getNumElements() != SAT->getNumElements()) return true; 209 return RecursiveResolveTypesI(DAT->getElementType(), SAT->getElementType(), 210 Pointers); 211 } 212 case Type::VectorTyID: { 213 const VectorType *DVT = cast<VectorType>(DstTy); 214 const VectorType *SVT = cast<VectorType>(SrcTy); 215 if (DVT->getNumElements() != SVT->getNumElements()) return true; 216 return RecursiveResolveTypesI(DVT->getElementType(), SVT->getElementType(), 217 Pointers); 218 } 219 case Type::PointerTyID: { 220 const PointerType *DstPT = cast<PointerType>(DstTy); 221 const PointerType *SrcPT = cast<PointerType>(SrcTy); 222 223 if (DstPT->getAddressSpace() != SrcPT->getAddressSpace()) 224 return true; 225 226 // If this is a pointer type, check to see if we have already seen it. If 227 // so, we are in a recursive branch. Cut off the search now. We cannot use 228 // an associative container for this search, because the type pointers (keys 229 // in the container) change whenever types get resolved. 230 if (SrcPT->isAbstract()) 231 if (const Type *ExistingDestTy = Pointers.lookup(SrcPT)) 232 return ExistingDestTy != DstPT; 233 234 if (DstPT->isAbstract()) 235 if (const Type *ExistingSrcTy = Pointers.lookup(DstPT)) 236 return ExistingSrcTy != SrcPT; 237 // Otherwise, add the current pointers to the vector to stop recursion on 238 // this pair. 239 if (DstPT->isAbstract()) 240 Pointers.insert(DstPT, SrcPT); 241 if (SrcPT->isAbstract()) 242 Pointers.insert(SrcPT, DstPT); 243 244 return RecursiveResolveTypesI(DstPT->getElementType(), 245 SrcPT->getElementType(), Pointers); 246 } 247 } 248} 249 250static bool RecursiveResolveTypes(const Type *DestTy, const Type *SrcTy) { 251 LinkerTypeMap PointerTypes; 252 return RecursiveResolveTypesI(DestTy, SrcTy, PointerTypes); 253} 254 255 256// LinkTypes - Go through the symbol table of the Src module and see if any 257// types are named in the src module that are not named in the Dst module. 258// Make sure there are no type name conflicts. 259static bool LinkTypes(Module *Dest, const Module *Src, std::string *Err) { 260 TypeSymbolTable *DestST = &Dest->getTypeSymbolTable(); 261 const TypeSymbolTable *SrcST = &Src->getTypeSymbolTable(); 262 263 // Look for a type plane for Type's... 264 TypeSymbolTable::const_iterator TI = SrcST->begin(); 265 TypeSymbolTable::const_iterator TE = SrcST->end(); 266 if (TI == TE) return false; // No named types, do nothing. 267 268 // Some types cannot be resolved immediately because they depend on other 269 // types being resolved to each other first. This contains a list of types we 270 // are waiting to recheck. 271 std::vector<std::string> DelayedTypesToResolve; 272 273 for ( ; TI != TE; ++TI ) { 274 const std::string &Name = TI->first; 275 const Type *RHS = TI->second; 276 277 // Check to see if this type name is already in the dest module. 278 Type *Entry = DestST->lookup(Name); 279 280 // If the name is just in the source module, bring it over to the dest. 281 if (Entry == 0) { 282 if (!Name.empty()) 283 DestST->insert(Name, const_cast<Type*>(RHS)); 284 } else if (ResolveTypes(Entry, RHS)) { 285 // They look different, save the types 'till later to resolve. 286 DelayedTypesToResolve.push_back(Name); 287 } 288 } 289 290 // Iteratively resolve types while we can... 291 while (!DelayedTypesToResolve.empty()) { 292 // Loop over all of the types, attempting to resolve them if possible... 293 unsigned OldSize = DelayedTypesToResolve.size(); 294 295 // Try direct resolution by name... 296 for (unsigned i = 0; i != DelayedTypesToResolve.size(); ++i) { 297 const std::string &Name = DelayedTypesToResolve[i]; 298 Type *T1 = SrcST->lookup(Name); 299 Type *T2 = DestST->lookup(Name); 300 if (!ResolveTypes(T2, T1)) { 301 // We are making progress! 302 DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i); 303 --i; 304 } 305 } 306 307 // Did we not eliminate any types? 308 if (DelayedTypesToResolve.size() == OldSize) { 309 // Attempt to resolve subelements of types. This allows us to merge these 310 // two types: { int* } and { opaque* } 311 for (unsigned i = 0, e = DelayedTypesToResolve.size(); i != e; ++i) { 312 const std::string &Name = DelayedTypesToResolve[i]; 313 if (!RecursiveResolveTypes(SrcST->lookup(Name), DestST->lookup(Name))) { 314 // We are making progress! 315 DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i); 316 317 // Go back to the main loop, perhaps we can resolve directly by name 318 // now... 319 break; 320 } 321 } 322 323 // If we STILL cannot resolve the types, then there is something wrong. 324 if (DelayedTypesToResolve.size() == OldSize) { 325 // Remove the symbol name from the destination. 326 DelayedTypesToResolve.pop_back(); 327 } 328 } 329 } 330 331 332 return false; 333} 334 335#ifndef NDEBUG 336static void PrintMap(const std::map<const Value*, Value*> &M) { 337 for (std::map<const Value*, Value*>::const_iterator I = M.begin(), E =M.end(); 338 I != E; ++I) { 339 cerr << " Fr: " << (void*)I->first << " "; 340 I->first->dump(); 341 cerr << " To: " << (void*)I->second << " "; 342 I->second->dump(); 343 cerr << "\n"; 344 } 345} 346#endif 347 348 349// RemapOperand - Use ValueMap to convert constants from one module to another. 350static Value *RemapOperand(const Value *In, 351 std::map<const Value*, Value*> &ValueMap) { 352 std::map<const Value*,Value*>::const_iterator I = ValueMap.find(In); 353 if (I != ValueMap.end()) 354 return I->second; 355 356 // Check to see if it's a constant that we are interested in transforming. 357 Value *Result = 0; 358 if (const Constant *CPV = dyn_cast<Constant>(In)) { 359 if ((!isa<DerivedType>(CPV->getType()) && !isa<ConstantExpr>(CPV)) || 360 isa<ConstantInt>(CPV) || isa<ConstantAggregateZero>(CPV)) 361 return const_cast<Constant*>(CPV); // Simple constants stay identical. 362 363 if (const ConstantArray *CPA = dyn_cast<ConstantArray>(CPV)) { 364 std::vector<Constant*> Operands(CPA->getNumOperands()); 365 for (unsigned i = 0, e = CPA->getNumOperands(); i != e; ++i) 366 Operands[i] =cast<Constant>(RemapOperand(CPA->getOperand(i), ValueMap)); 367 Result = ConstantArray::get(cast<ArrayType>(CPA->getType()), Operands); 368 } else if (const ConstantStruct *CPS = dyn_cast<ConstantStruct>(CPV)) { 369 std::vector<Constant*> Operands(CPS->getNumOperands()); 370 for (unsigned i = 0, e = CPS->getNumOperands(); i != e; ++i) 371 Operands[i] =cast<Constant>(RemapOperand(CPS->getOperand(i), ValueMap)); 372 Result = ConstantStruct::get(cast<StructType>(CPS->getType()), Operands); 373 } else if (isa<ConstantPointerNull>(CPV) || isa<UndefValue>(CPV)) { 374 Result = const_cast<Constant*>(CPV); 375 } else if (const ConstantVector *CP = dyn_cast<ConstantVector>(CPV)) { 376 std::vector<Constant*> Operands(CP->getNumOperands()); 377 for (unsigned i = 0, e = CP->getNumOperands(); i != e; ++i) 378 Operands[i] = cast<Constant>(RemapOperand(CP->getOperand(i), ValueMap)); 379 Result = ConstantVector::get(Operands); 380 } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CPV)) { 381 std::vector<Constant*> Ops; 382 for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) 383 Ops.push_back(cast<Constant>(RemapOperand(CE->getOperand(i),ValueMap))); 384 Result = CE->getWithOperands(Ops); 385 } else { 386 assert(!isa<GlobalValue>(CPV) && "Unmapped global?"); 387 assert(0 && "Unknown type of derived type constant value!"); 388 } 389 } else if (isa<InlineAsm>(In)) { 390 Result = const_cast<Value*>(In); 391 } 392 393 // Cache the mapping in our local map structure 394 if (Result) { 395 ValueMap[In] = Result; 396 return Result; 397 } 398 399#ifndef NDEBUG 400 cerr << "LinkModules ValueMap: \n"; 401 PrintMap(ValueMap); 402 403 cerr << "Couldn't remap value: " << (void*)In << " " << *In << "\n"; 404 assert(0 && "Couldn't remap value!"); 405#endif 406 return 0; 407} 408 409/// ForceRenaming - The LLVM SymbolTable class autorenames globals that conflict 410/// in the symbol table. This is good for all clients except for us. Go 411/// through the trouble to force this back. 412static void ForceRenaming(GlobalValue *GV, const std::string &Name) { 413 assert(GV->getName() != Name && "Can't force rename to self"); 414 ValueSymbolTable &ST = GV->getParent()->getValueSymbolTable(); 415 416 // If there is a conflict, rename the conflict. 417 if (GlobalValue *ConflictGV = cast_or_null<GlobalValue>(ST.lookup(Name))) { 418 assert(ConflictGV->hasInternalLinkage() && 419 "Not conflicting with a static global, should link instead!"); 420 GV->takeName(ConflictGV); 421 ConflictGV->setName(Name); // This will cause ConflictGV to get renamed 422 assert(ConflictGV->getName() != Name && "ForceRenaming didn't work"); 423 } else { 424 GV->setName(Name); // Force the name back 425 } 426} 427 428/// CopyGVAttributes - copy additional attributes (those not needed to construct 429/// a GlobalValue) from the SrcGV to the DestGV. 430static void CopyGVAttributes(GlobalValue *DestGV, const GlobalValue *SrcGV) { 431 // Use the maximum alignment, rather than just copying the alignment of SrcGV. 432 unsigned Alignment = std::max(DestGV->getAlignment(), SrcGV->getAlignment()); 433 DestGV->copyAttributesFrom(SrcGV); 434 DestGV->setAlignment(Alignment); 435} 436 437/// GetLinkageResult - This analyzes the two global values and determines what 438/// the result will look like in the destination module. In particular, it 439/// computes the resultant linkage type, computes whether the global in the 440/// source should be copied over to the destination (replacing the existing 441/// one), and computes whether this linkage is an error or not. It also performs 442/// visibility checks: we cannot link together two symbols with different 443/// visibilities. 444static bool GetLinkageResult(GlobalValue *Dest, const GlobalValue *Src, 445 GlobalValue::LinkageTypes <, bool &LinkFromSrc, 446 std::string *Err) { 447 assert((!Dest || !Src->hasInternalLinkage()) && 448 "If Src has internal linkage, Dest shouldn't be set!"); 449 if (!Dest) { 450 // Linking something to nothing. 451 LinkFromSrc = true; 452 LT = Src->getLinkage(); 453 } else if (Src->isDeclaration()) { 454 // If Src is external or if both Src & Dest are external.. Just link the 455 // external globals, we aren't adding anything. 456 if (Src->hasDLLImportLinkage()) { 457 // If one of GVs has DLLImport linkage, result should be dllimport'ed. 458 if (Dest->isDeclaration()) { 459 LinkFromSrc = true; 460 LT = Src->getLinkage(); 461 } 462 } else if (Dest->hasExternalWeakLinkage()) { 463 //If the Dest is weak, use the source linkage 464 LinkFromSrc = true; 465 LT = Src->getLinkage(); 466 } else { 467 LinkFromSrc = false; 468 LT = Dest->getLinkage(); 469 } 470 } else if (Dest->isDeclaration() && !Dest->hasDLLImportLinkage()) { 471 // If Dest is external but Src is not: 472 LinkFromSrc = true; 473 LT = Src->getLinkage(); 474 } else if (Src->hasAppendingLinkage() || Dest->hasAppendingLinkage()) { 475 if (Src->getLinkage() != Dest->getLinkage()) 476 return Error(Err, "Linking globals named '" + Src->getName() + 477 "': can only link appending global with another appending global!"); 478 LinkFromSrc = true; // Special cased. 479 LT = Src->getLinkage(); 480 } else if (Src->mayBeOverridden()) { 481 // At this point we know that Dest has LinkOnce, External*, Weak, Common, 482 // or DLL* linkage. 483 if ((Dest->hasLinkOnceLinkage() && 484 (Src->hasWeakLinkage() || Src->hasCommonLinkage())) || 485 Dest->hasExternalWeakLinkage()) { 486 LinkFromSrc = true; 487 LT = Src->getLinkage(); 488 } else { 489 LinkFromSrc = false; 490 LT = Dest->getLinkage(); 491 } 492 } else if (Dest->mayBeOverridden()) { 493 // At this point we know that Src has External* or DLL* linkage. 494 if (Src->hasExternalWeakLinkage()) { 495 LinkFromSrc = false; 496 LT = Dest->getLinkage(); 497 } else { 498 LinkFromSrc = true; 499 LT = GlobalValue::ExternalLinkage; 500 } 501 } else { 502 assert((Dest->hasExternalLinkage() || 503 Dest->hasDLLImportLinkage() || 504 Dest->hasDLLExportLinkage() || 505 Dest->hasExternalWeakLinkage()) && 506 (Src->hasExternalLinkage() || 507 Src->hasDLLImportLinkage() || 508 Src->hasDLLExportLinkage() || 509 Src->hasExternalWeakLinkage()) && 510 "Unexpected linkage type!"); 511 return Error(Err, "Linking globals named '" + Src->getName() + 512 "': symbol multiply defined!"); 513 } 514 515 // Check visibility 516 if (Dest && Src->getVisibility() != Dest->getVisibility()) 517 if (!Src->isDeclaration() && !Dest->isDeclaration()) 518 return Error(Err, "Linking globals named '" + Src->getName() + 519 "': symbols have different visibilities!"); 520 return false; 521} 522 523// LinkGlobals - Loop through the global variables in the src module and merge 524// them into the dest module. 525static bool LinkGlobals(Module *Dest, const Module *Src, 526 std::map<const Value*, Value*> &ValueMap, 527 std::multimap<std::string, GlobalVariable *> &AppendingVars, 528 std::string *Err) { 529 ValueSymbolTable &DestSymTab = Dest->getValueSymbolTable(); 530 531 // Loop over all of the globals in the src module, mapping them over as we go 532 for (Module::const_global_iterator I = Src->global_begin(), 533 E = Src->global_end(); I != E; ++I) { 534 const GlobalVariable *SGV = I; 535 GlobalValue *DGV = 0; 536 537 // Check to see if may have to link the global with the global, alias or 538 // function. 539 if (SGV->hasName() && !SGV->hasInternalLinkage()) 540 DGV = cast_or_null<GlobalValue>(DestSymTab.lookup(SGV->getNameStart(), 541 SGV->getNameEnd())); 542 543 // If we found a global with the same name in the dest module, but it has 544 // internal linkage, we are really not doing any linkage here. 545 if (DGV && DGV->hasInternalLinkage()) 546 DGV = 0; 547 548 // If types don't agree due to opaque types, try to resolve them. 549 if (DGV && DGV->getType() != SGV->getType()) 550 RecursiveResolveTypes(SGV->getType(), DGV->getType()); 551 552 assert((SGV->hasInitializer() || SGV->hasExternalWeakLinkage() || 553 SGV->hasExternalLinkage() || SGV->hasDLLImportLinkage()) && 554 "Global must either be external or have an initializer!"); 555 556 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; 557 bool LinkFromSrc = false; 558 if (GetLinkageResult(DGV, SGV, NewLinkage, LinkFromSrc, Err)) 559 return true; 560 561 if (DGV == 0) { 562 // No linking to be performed, simply create an identical version of the 563 // symbol over in the dest module... the initializer will be filled in 564 // later by LinkGlobalInits. 565 GlobalVariable *NewDGV = 566 new GlobalVariable(SGV->getType()->getElementType(), 567 SGV->isConstant(), SGV->getLinkage(), /*init*/0, 568 SGV->getName(), Dest, false, 569 SGV->getType()->getAddressSpace()); 570 // Propagate alignment, visibility and section info. 571 CopyGVAttributes(NewDGV, SGV); 572 573 // If the LLVM runtime renamed the global, but it is an externally visible 574 // symbol, DGV must be an existing global with internal linkage. Rename 575 // it. 576 if (!NewDGV->hasInternalLinkage() && NewDGV->getName() != SGV->getName()) 577 ForceRenaming(NewDGV, SGV->getName()); 578 579 // Make sure to remember this mapping. 580 ValueMap[SGV] = NewDGV; 581 582 // Keep track that this is an appending variable. 583 if (SGV->hasAppendingLinkage()) 584 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV)); 585 continue; 586 } 587 588 // If the visibilities of the symbols disagree and the destination is a 589 // prototype, take the visibility of its input. 590 if (DGV->isDeclaration()) 591 DGV->setVisibility(SGV->getVisibility()); 592 593 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 continue; 615 } 616 617 if (LinkFromSrc) { 618 if (isa<GlobalAlias>(DGV)) 619 return Error(Err, "Global-Alias Collision on '" + SGV->getName() + 620 "': symbol multiple defined"); 621 622 // If the types don't match, and if we are to link from the source, nuke 623 // DGV and create a new one of the appropriate type. Note that the thing 624 // we are replacing may be a function (if a prototype, weak, etc) or a 625 // global variable. 626 GlobalVariable *NewDGV = 627 new GlobalVariable(SGV->getType()->getElementType(), SGV->isConstant(), 628 NewLinkage, /*init*/0, DGV->getName(), Dest, false, 629 SGV->getType()->getAddressSpace()); 630 631 // Propagate alignment, section, and visibility info. 632 CopyGVAttributes(NewDGV, SGV); 633 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDGV, DGV->getType())); 634 635 // DGV will conflict with NewDGV because they both had the same 636 // name. We must erase this now so ForceRenaming doesn't assert 637 // because DGV might not have internal linkage. 638 if (GlobalVariable *Var = dyn_cast<GlobalVariable>(DGV)) 639 Var->eraseFromParent(); 640 else 641 cast<Function>(DGV)->eraseFromParent(); 642 DGV = NewDGV; 643 644 // If the symbol table renamed the global, but it is an externally visible 645 // symbol, DGV must be an existing global with internal linkage. Rename. 646 if (NewDGV->getName() != SGV->getName() && !NewDGV->hasInternalLinkage()) 647 ForceRenaming(NewDGV, SGV->getName()); 648 649 // Inherit const as appropriate. 650 NewDGV->setConstant(SGV->isConstant()); 651 652 // Make sure to remember this mapping. 653 ValueMap[SGV] = NewDGV; 654 continue; 655 } 656 657 // Not "link from source", keep the one in the DestModule and remap the 658 // input onto it. 659 660 // Special case for const propagation. 661 if (GlobalVariable *DGVar = dyn_cast<GlobalVariable>(DGV)) 662 if (DGVar->isDeclaration() && SGV->isConstant() && !DGVar->isConstant()) 663 DGVar->setConstant(true); 664 665 // SGV is global, but DGV is alias. The only valid mapping is when SGV is 666 // external declaration, which is effectively a no-op. Also make sure 667 // linkage calculation was correct. 668 if (isa<GlobalAlias>(DGV) && !SGV->isDeclaration()) 669 return Error(Err, "Global-Alias Collision on '" + SGV->getName() + 670 "': symbol multiple defined"); 671 672 // Set calculated linkage 673 DGV->setLinkage(NewLinkage); 674 675 // Make sure to remember this mapping... 676 ValueMap[SGV] = ConstantExpr::getBitCast(DGV, SGV->getType()); 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->mayBeOverridden()) { 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->mayBeOverridden()) { 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->mayBeOverridden()) { 866 // Nothing is required, mapped values will take the new global 867 // automatically. 868 } else if (SGV->mayBeOverridden()) { 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; 898 899 // Check to see if may have to link the function with the global, alias or 900 // function. 901 if (SF->hasName() && !SF->hasInternalLinkage()) 902 DGV = cast_or_null<GlobalValue>(DestSymTab.lookup(SF->getNameStart(), 903 SF->getNameEnd())); 904 905 // If we found a global with the same name in the dest module, but it has 906 // internal linkage, we are really not doing any linkage here. 907 if (DGV && DGV->hasInternalLinkage()) 908 DGV = 0; 909 910 // If types don't agree due to opaque types, try to resolve them. 911 if (DGV && DGV->getType() != SF->getType()) 912 RecursiveResolveTypes(SF->getType(), DGV->getType()); 913 914 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; 915 bool LinkFromSrc = false; 916 if (GetLinkageResult(DGV, SF, NewLinkage, LinkFromSrc, Err)) 917 return true; 918 919 // If there is no linkage to be performed, just bring over SF without 920 // modifying it. 921 if (DGV == 0) { 922 // Function does not already exist, simply insert an function signature 923 // identical to SF into the dest module. 924 Function *NewDF = Function::Create(SF->getFunctionType(), 925 SF->getLinkage(), 926 SF->getName(), Dest); 927 CopyGVAttributes(NewDF, SF); 928 929 // If the LLVM runtime renamed the function, but it is an externally 930 // visible symbol, DF must be an existing function with internal linkage. 931 // Rename it. 932 if (!NewDF->hasInternalLinkage() && NewDF->getName() != SF->getName()) 933 ForceRenaming(NewDF, SF->getName()); 934 935 // ... and remember this mapping... 936 ValueMap[SF] = NewDF; 937 continue; 938 } 939 940 // If the visibilities of the symbols disagree and the destination is a 941 // prototype, take the visibility of its input. 942 if (DGV->isDeclaration()) 943 DGV->setVisibility(SF->getVisibility()); 944 945 if (LinkFromSrc) { 946 if (isa<GlobalAlias>(DGV)) 947 return Error(Err, "Function-Alias Collision on '" + SF->getName() + 948 "': symbol multiple defined"); 949 950 // We have a definition of the same name but different type in the 951 // source module. Copy the prototype to the destination and replace 952 // uses of the destination's prototype with the new prototype. 953 Function *NewDF = Function::Create(SF->getFunctionType(), NewLinkage, 954 SF->getName(), Dest); 955 CopyGVAttributes(NewDF, SF); 956 957 // Any uses of DF need to change to NewDF, with cast 958 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDF, DGV->getType())); 959 960 // DF will conflict with NewDF because they both had the same. We must 961 // erase this now so ForceRenaming doesn't assert because DF might 962 // not have internal linkage. 963 if (GlobalVariable *Var = dyn_cast<GlobalVariable>(DGV)) 964 Var->eraseFromParent(); 965 else 966 cast<Function>(DGV)->eraseFromParent(); 967 968 // If the symbol table renamed the function, but it is an externally 969 // visible symbol, DF must be an existing function with internal 970 // linkage. Rename it. 971 if (NewDF->getName() != SF->getName() && !NewDF->hasInternalLinkage()) 972 ForceRenaming(NewDF, SF->getName()); 973 974 // Remember this mapping so uses in the source module get remapped 975 // later by RemapOperand. 976 ValueMap[SF] = NewDF; 977 continue; 978 } 979 980 // Not "link from source", keep the one in the DestModule and remap the 981 // input onto it. 982 983 if (isa<GlobalAlias>(DGV)) { 984 // The only valid mappings are: 985 // - SF is external declaration, which is effectively a no-op. 986 // - SF is weak, when we just need to throw SF out. 987 if (!SF->isDeclaration()) 988 return Error(Err, "Function-Alias Collision on '" + SF->getName() + 989 "': symbol multiple defined"); 990 } 991 992 // Set calculated linkage 993 DGV->setLinkage(NewLinkage); 994 995 // Make sure to remember this mapping. 996 ValueMap[SF] = ConstantExpr::getBitCast(DGV, SF->getType()); 997 } 998 return false; 999} 1000 1001// LinkFunctionBody - Copy the source function over into the dest function and 1002// fix up references to values. At this point we know that Dest is an external 1003// function, and that Src is not. 1004static bool LinkFunctionBody(Function *Dest, Function *Src, 1005 std::map<const Value*, Value*> &ValueMap, 1006 std::string *Err) { 1007 assert(Src && Dest && Dest->isDeclaration() && !Src->isDeclaration()); 1008 1009 // Go through and convert function arguments over, remembering the mapping. 1010 Function::arg_iterator DI = Dest->arg_begin(); 1011 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end(); 1012 I != E; ++I, ++DI) { 1013 DI->setName(I->getName()); // Copy the name information over... 1014 1015 // Add a mapping to our local map 1016 ValueMap[I] = DI; 1017 } 1018 1019 // Splice the body of the source function into the dest function. 1020 Dest->getBasicBlockList().splice(Dest->end(), Src->getBasicBlockList()); 1021 1022 // At this point, all of the instructions and values of the function are now 1023 // copied over. The only problem is that they are still referencing values in 1024 // the Source function as operands. Loop through all of the operands of the 1025 // functions and patch them up to point to the local versions... 1026 // 1027 for (Function::iterator BB = Dest->begin(), BE = Dest->end(); BB != BE; ++BB) 1028 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) 1029 for (Instruction::op_iterator OI = I->op_begin(), OE = I->op_end(); 1030 OI != OE; ++OI) 1031 if (!isa<Instruction>(*OI) && !isa<BasicBlock>(*OI)) 1032 *OI = RemapOperand(*OI, ValueMap); 1033 1034 // There is no need to map the arguments anymore. 1035 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end(); 1036 I != E; ++I) 1037 ValueMap.erase(I); 1038 1039 return false; 1040} 1041 1042 1043// LinkFunctionBodies - Link in the function bodies that are defined in the 1044// source module into the DestModule. This consists basically of copying the 1045// function over and fixing up references to values. 1046static bool LinkFunctionBodies(Module *Dest, Module *Src, 1047 std::map<const Value*, Value*> &ValueMap, 1048 std::string *Err) { 1049 1050 // Loop over all of the functions in the src module, mapping them over as we 1051 // go 1052 for (Module::iterator SF = Src->begin(), E = Src->end(); SF != E; ++SF) { 1053 if (!SF->isDeclaration()) { // No body if function is external 1054 Function *DF = dyn_cast<Function>(ValueMap[SF]); // Destination function 1055 1056 // DF not external SF external? 1057 if (DF && DF->isDeclaration()) 1058 // Only provide the function body if there isn't one already. 1059 if (LinkFunctionBody(DF, SF, ValueMap, Err)) 1060 return true; 1061 } 1062 } 1063 return false; 1064} 1065 1066// LinkAppendingVars - If there were any appending global variables, link them 1067// together now. Return true on error. 1068static bool LinkAppendingVars(Module *M, 1069 std::multimap<std::string, GlobalVariable *> &AppendingVars, 1070 std::string *ErrorMsg) { 1071 if (AppendingVars.empty()) return false; // Nothing to do. 1072 1073 // Loop over the multimap of appending vars, processing any variables with the 1074 // same name, forming a new appending global variable with both of the 1075 // initializers merged together, then rewrite references to the old variables 1076 // and delete them. 1077 std::vector<Constant*> Inits; 1078 while (AppendingVars.size() > 1) { 1079 // Get the first two elements in the map... 1080 std::multimap<std::string, 1081 GlobalVariable*>::iterator Second = AppendingVars.begin(), First=Second++; 1082 1083 // If the first two elements are for different names, there is no pair... 1084 // Otherwise there is a pair, so link them together... 1085 if (First->first == Second->first) { 1086 GlobalVariable *G1 = First->second, *G2 = Second->second; 1087 const ArrayType *T1 = cast<ArrayType>(G1->getType()->getElementType()); 1088 const ArrayType *T2 = cast<ArrayType>(G2->getType()->getElementType()); 1089 1090 // Check to see that they two arrays agree on type... 1091 if (T1->getElementType() != T2->getElementType()) 1092 return Error(ErrorMsg, 1093 "Appending variables with different element types need to be linked!"); 1094 if (G1->isConstant() != G2->isConstant()) 1095 return Error(ErrorMsg, 1096 "Appending variables linked with different const'ness!"); 1097 1098 if (G1->getAlignment() != G2->getAlignment()) 1099 return Error(ErrorMsg, 1100 "Appending variables with different alignment need to be linked!"); 1101 1102 if (G1->getVisibility() != G2->getVisibility()) 1103 return Error(ErrorMsg, 1104 "Appending variables with different visibility need to be linked!"); 1105 1106 if (G1->getSection() != G2->getSection()) 1107 return Error(ErrorMsg, 1108 "Appending variables with different section name need to be linked!"); 1109 1110 unsigned NewSize = T1->getNumElements() + T2->getNumElements(); 1111 ArrayType *NewType = ArrayType::get(T1->getElementType(), NewSize); 1112 1113 G1->setName(""); // Clear G1's name in case of a conflict! 1114 1115 // Create the new global variable... 1116 GlobalVariable *NG = 1117 new GlobalVariable(NewType, G1->isConstant(), G1->getLinkage(), 1118 /*init*/0, First->first, M, G1->isThreadLocal(), 1119 G1->getType()->getAddressSpace()); 1120 1121 // Propagate alignment, visibility and section info. 1122 CopyGVAttributes(NG, G1); 1123 1124 // Merge the initializer... 1125 Inits.reserve(NewSize); 1126 if (ConstantArray *I = dyn_cast<ConstantArray>(G1->getInitializer())) { 1127 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i) 1128 Inits.push_back(I->getOperand(i)); 1129 } else { 1130 assert(isa<ConstantAggregateZero>(G1->getInitializer())); 1131 Constant *CV = Constant::getNullValue(T1->getElementType()); 1132 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i) 1133 Inits.push_back(CV); 1134 } 1135 if (ConstantArray *I = dyn_cast<ConstantArray>(G2->getInitializer())) { 1136 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i) 1137 Inits.push_back(I->getOperand(i)); 1138 } else { 1139 assert(isa<ConstantAggregateZero>(G2->getInitializer())); 1140 Constant *CV = Constant::getNullValue(T2->getElementType()); 1141 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i) 1142 Inits.push_back(CV); 1143 } 1144 NG->setInitializer(ConstantArray::get(NewType, Inits)); 1145 Inits.clear(); 1146 1147 // Replace any uses of the two global variables with uses of the new 1148 // global... 1149 1150 // FIXME: This should rewrite simple/straight-forward uses such as 1151 // getelementptr instructions to not use the Cast! 1152 G1->replaceAllUsesWith(ConstantExpr::getBitCast(NG, G1->getType())); 1153 G2->replaceAllUsesWith(ConstantExpr::getBitCast(NG, G2->getType())); 1154 1155 // Remove the two globals from the module now... 1156 M->getGlobalList().erase(G1); 1157 M->getGlobalList().erase(G2); 1158 1159 // Put the new global into the AppendingVars map so that we can handle 1160 // linking of more than two vars... 1161 Second->second = NG; 1162 } 1163 AppendingVars.erase(First); 1164 } 1165 1166 return false; 1167} 1168 1169static bool ResolveAliases(Module *Dest) { 1170 for (Module::alias_iterator I = Dest->alias_begin(), E = Dest->alias_end(); 1171 I != E; ++I) 1172 if (const GlobalValue *GV = I->resolveAliasedGlobal()) 1173 if (GV != I && !GV->isDeclaration()) 1174 I->replaceAllUsesWith(const_cast<GlobalValue*>(GV)); 1175 1176 return false; 1177} 1178 1179// LinkModules - This function links two modules together, with the resulting 1180// left module modified to be the composite of the two input modules. If an 1181// error occurs, true is returned and ErrorMsg (if not null) is set to indicate 1182// the problem. Upon failure, the Dest module could be in a modified state, and 1183// shouldn't be relied on to be consistent. 1184bool 1185Linker::LinkModules(Module *Dest, Module *Src, std::string *ErrorMsg) { 1186 assert(Dest != 0 && "Invalid Destination module"); 1187 assert(Src != 0 && "Invalid Source Module"); 1188 1189 if (Dest->getDataLayout().empty()) { 1190 if (!Src->getDataLayout().empty()) { 1191 Dest->setDataLayout(Src->getDataLayout()); 1192 } else { 1193 std::string DataLayout; 1194 1195 if (Dest->getEndianness() == Module::AnyEndianness) { 1196 if (Src->getEndianness() == Module::BigEndian) 1197 DataLayout.append("E"); 1198 else if (Src->getEndianness() == Module::LittleEndian) 1199 DataLayout.append("e"); 1200 } 1201 1202 if (Dest->getPointerSize() == Module::AnyPointerSize) { 1203 if (Src->getPointerSize() == Module::Pointer64) 1204 DataLayout.append(DataLayout.length() == 0 ? "p:64:64" : "-p:64:64"); 1205 else if (Src->getPointerSize() == Module::Pointer32) 1206 DataLayout.append(DataLayout.length() == 0 ? "p:32:32" : "-p:32:32"); 1207 } 1208 Dest->setDataLayout(DataLayout); 1209 } 1210 } 1211 1212 // Copy the target triple from the source to dest if the dest's is empty. 1213 if (Dest->getTargetTriple().empty() && !Src->getTargetTriple().empty()) 1214 Dest->setTargetTriple(Src->getTargetTriple()); 1215 1216 if (!Src->getDataLayout().empty() && !Dest->getDataLayout().empty() && 1217 Src->getDataLayout() != Dest->getDataLayout()) 1218 cerr << "WARNING: Linking two modules of different data layouts!\n"; 1219 if (!Src->getTargetTriple().empty() && 1220 Dest->getTargetTriple() != Src->getTargetTriple()) 1221 cerr << "WARNING: Linking two modules of different target triples!\n"; 1222 1223 // Append the module inline asm string. 1224 if (!Src->getModuleInlineAsm().empty()) { 1225 if (Dest->getModuleInlineAsm().empty()) 1226 Dest->setModuleInlineAsm(Src->getModuleInlineAsm()); 1227 else 1228 Dest->setModuleInlineAsm(Dest->getModuleInlineAsm()+"\n"+ 1229 Src->getModuleInlineAsm()); 1230 } 1231 1232 // Update the destination module's dependent libraries list with the libraries 1233 // from the source module. There's no opportunity for duplicates here as the 1234 // Module ensures that duplicate insertions are discarded. 1235 for (Module::lib_iterator SI = Src->lib_begin(), SE = Src->lib_end(); 1236 SI != SE; ++SI) 1237 Dest->addLibrary(*SI); 1238 1239 // LinkTypes - Go through the symbol table of the Src module and see if any 1240 // types are named in the src module that are not named in the Dst module. 1241 // Make sure there are no type name conflicts. 1242 if (LinkTypes(Dest, Src, ErrorMsg)) 1243 return true; 1244 1245 // ValueMap - Mapping of values from what they used to be in Src, to what they 1246 // are now in Dest. 1247 std::map<const Value*, Value*> ValueMap; 1248 1249 // AppendingVars - Keep track of global variables in the destination module 1250 // with appending linkage. After the module is linked together, they are 1251 // appended and the module is rewritten. 1252 std::multimap<std::string, GlobalVariable *> AppendingVars; 1253 for (Module::global_iterator I = Dest->global_begin(), E = Dest->global_end(); 1254 I != E; ++I) { 1255 // Add all of the appending globals already in the Dest module to 1256 // AppendingVars. 1257 if (I->hasAppendingLinkage()) 1258 AppendingVars.insert(std::make_pair(I->getName(), I)); 1259 } 1260 1261 // Insert all of the globals in src into the Dest module... without linking 1262 // initializers (which could refer to functions not yet mapped over). 1263 if (LinkGlobals(Dest, Src, ValueMap, AppendingVars, ErrorMsg)) 1264 return true; 1265 1266 // Link the functions together between the two modules, without doing function 1267 // bodies... this just adds external function prototypes to the Dest 1268 // function... We do this so that when we begin processing function bodies, 1269 // all of the global values that may be referenced are available in our 1270 // ValueMap. 1271 if (LinkFunctionProtos(Dest, Src, ValueMap, ErrorMsg)) 1272 return true; 1273 1274 // If there were any alias, link them now. We really need to do this now, 1275 // because all of the aliases that may be referenced need to be available in 1276 // ValueMap 1277 if (LinkAlias(Dest, Src, ValueMap, ErrorMsg)) return true; 1278 1279 // Update the initializers in the Dest module now that all globals that may 1280 // be referenced are in Dest. 1281 if (LinkGlobalInits(Dest, Src, ValueMap, ErrorMsg)) return true; 1282 1283 // Link in the function bodies that are defined in the source module into the 1284 // DestModule. This consists basically of copying the function over and 1285 // fixing up references to values. 1286 if (LinkFunctionBodies(Dest, Src, ValueMap, ErrorMsg)) return true; 1287 1288 // If there were any appending global variables, link them together now. 1289 if (LinkAppendingVars(Dest, AppendingVars, ErrorMsg)) return true; 1290 1291 // Resolve all uses of aliases with aliasees 1292 if (ResolveAliases(Dest)) return true; 1293 1294 // If the source library's module id is in the dependent library list of the 1295 // destination library, remove it since that module is now linked in. 1296 sys::Path modId; 1297 modId.set(Src->getModuleIdentifier()); 1298 if (!modId.isEmpty()) 1299 Dest->removeLibrary(modId.getBasename()); 1300 1301 return false; 1302} 1303 1304// vim: sw=2 1305