LinkModules.cpp revision 0e65857392c8661b7df689bb184dde4b9e17a2f8
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->hasLocalLinkage() && 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->hasLocalLinkage()) && 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->hasLocalLinkage()) 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->hasLocalLinkage()) 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->hasLocalLinkage() && 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->hasLocalLinkage()) 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. 666 if (isa<GlobalAlias>(DGV)) { 667 // The only valid mappings are: 668 // - SGV is external declaration, which is effectively a no-op. 669 // - SGV is weak, when we just need to throw SGV out. 670 if (!SGV->isDeclaration() && !SGV->mayBeOverridden()) 671 return Error(Err, "Global-Alias Collision on '" + SGV->getName() + 672 "': symbol multiple defined"); 673 } 674 675 // Set calculated linkage 676 DGV->setLinkage(NewLinkage); 677 678 // Make sure to remember this mapping... 679 ValueMap[SGV] = ConstantExpr::getBitCast(DGV, SGV->getType()); 680 } 681 return false; 682} 683 684static GlobalValue::LinkageTypes 685CalculateAliasLinkage(const GlobalValue *SGV, const GlobalValue *DGV) { 686 if (SGV->hasExternalLinkage() || DGV->hasExternalLinkage()) 687 return GlobalValue::ExternalLinkage; 688 else if (SGV->hasWeakLinkage() || DGV->hasWeakLinkage()) 689 return GlobalValue::WeakLinkage; 690 else if (SGV->hasInternalLinkage() && DGV->hasInternalLinkage()) 691 return GlobalValue::InternalLinkage; 692 else { 693 assert (SGV->hasPrivateLinkage() && DGV->hasPrivateLinkage() && 694 "Unexpected linkage type"); 695 return GlobalValue::PrivateLinkage; 696 } 697} 698 699// LinkAlias - Loop through the alias in the src module and link them into the 700// dest module. We're assuming, that all functions/global variables were already 701// linked in. 702static bool LinkAlias(Module *Dest, const Module *Src, 703 std::map<const Value*, Value*> &ValueMap, 704 std::string *Err) { 705 // Loop over all alias in the src module 706 for (Module::const_alias_iterator I = Src->alias_begin(), 707 E = Src->alias_end(); I != E; ++I) { 708 const GlobalAlias *SGA = I; 709 const GlobalValue *SAliasee = SGA->getAliasedGlobal(); 710 GlobalAlias *NewGA = NULL; 711 712 // Globals were already linked, thus we can just query ValueMap for variant 713 // of SAliasee in Dest. 714 std::map<const Value*,Value*>::const_iterator VMI = ValueMap.find(SAliasee); 715 assert(VMI != ValueMap.end() && "Aliasee not linked"); 716 GlobalValue* DAliasee = cast<GlobalValue>(VMI->second); 717 GlobalValue* DGV = NULL; 718 719 // Try to find something 'similar' to SGA in destination module. 720 if (!DGV && !SGA->hasLocalLinkage()) { 721 DGV = Dest->getNamedAlias(SGA->getName()); 722 723 // If types don't agree due to opaque types, try to resolve them. 724 if (DGV && DGV->getType() != SGA->getType()) 725 RecursiveResolveTypes(SGA->getType(), DGV->getType()); 726 } 727 728 if (!DGV && !SGA->hasLocalLinkage()) { 729 DGV = Dest->getGlobalVariable(SGA->getName()); 730 731 // If types don't agree due to opaque types, try to resolve them. 732 if (DGV && DGV->getType() != SGA->getType()) 733 RecursiveResolveTypes(SGA->getType(), DGV->getType()); 734 } 735 736 if (!DGV && !SGA->hasLocalLinkage()) { 737 DGV = Dest->getFunction(SGA->getName()); 738 739 // If types don't agree due to opaque types, try to resolve them. 740 if (DGV && DGV->getType() != SGA->getType()) 741 RecursiveResolveTypes(SGA->getType(), DGV->getType()); 742 } 743 744 // No linking to be performed on internal stuff. 745 if (DGV && DGV->hasLocalLinkage()) 746 DGV = NULL; 747 748 if (GlobalAlias *DGA = dyn_cast_or_null<GlobalAlias>(DGV)) { 749 // Types are known to be the same, check whether aliasees equal. As 750 // globals are already linked we just need query ValueMap to find the 751 // mapping. 752 if (DAliasee == DGA->getAliasedGlobal()) { 753 // This is just two copies of the same alias. Propagate linkage, if 754 // necessary. 755 DGA->setLinkage(CalculateAliasLinkage(SGA, DGA)); 756 757 NewGA = DGA; 758 // Proceed to 'common' steps 759 } else 760 return Error(Err, "Alias Collision on '" + SGA->getName()+ 761 "': aliases have different aliasees"); 762 } else if (GlobalVariable *DGVar = dyn_cast_or_null<GlobalVariable>(DGV)) { 763 // The only allowed way is to link alias with external declaration or weak 764 // symbol.. 765 if (DGVar->isDeclaration() || DGVar->mayBeOverridden()) { 766 // But only if aliasee is global too... 767 if (!isa<GlobalVariable>(DAliasee)) 768 return Error(Err, "Global-Alias Collision on '" + SGA->getName() + 769 "': aliasee is not global variable"); 770 771 NewGA = new GlobalAlias(SGA->getType(), SGA->getLinkage(), 772 SGA->getName(), DAliasee, Dest); 773 CopyGVAttributes(NewGA, SGA); 774 775 // Any uses of DGV need to change to NewGA, with cast, if needed. 776 if (SGA->getType() != DGVar->getType()) 777 DGVar->replaceAllUsesWith(ConstantExpr::getBitCast(NewGA, 778 DGVar->getType())); 779 else 780 DGVar->replaceAllUsesWith(NewGA); 781 782 // DGVar will conflict with NewGA because they both had the same 783 // name. We must erase this now so ForceRenaming doesn't assert 784 // because DGV might not have internal linkage. 785 DGVar->eraseFromParent(); 786 787 // Proceed to 'common' steps 788 } else 789 return Error(Err, "Global-Alias Collision on '" + SGA->getName() + 790 "': symbol multiple defined"); 791 } else if (Function *DF = dyn_cast_or_null<Function>(DGV)) { 792 // The only allowed way is to link alias with external declaration or weak 793 // symbol... 794 if (DF->isDeclaration() || DF->mayBeOverridden()) { 795 // But only if aliasee is function too... 796 if (!isa<Function>(DAliasee)) 797 return Error(Err, "Function-Alias Collision on '" + SGA->getName() + 798 "': aliasee is not function"); 799 800 NewGA = new GlobalAlias(SGA->getType(), SGA->getLinkage(), 801 SGA->getName(), DAliasee, Dest); 802 CopyGVAttributes(NewGA, SGA); 803 804 // Any uses of DF need to change to NewGA, with cast, if needed. 805 if (SGA->getType() != DF->getType()) 806 DF->replaceAllUsesWith(ConstantExpr::getBitCast(NewGA, 807 DF->getType())); 808 else 809 DF->replaceAllUsesWith(NewGA); 810 811 // DF will conflict with NewGA because they both had the same 812 // name. We must erase this now so ForceRenaming doesn't assert 813 // because DF might not have internal linkage. 814 DF->eraseFromParent(); 815 816 // Proceed to 'common' steps 817 } else 818 return Error(Err, "Function-Alias Collision on '" + SGA->getName() + 819 "': symbol multiple defined"); 820 } else { 821 // No linking to be performed, simply create an identical version of the 822 // alias over in the dest module... 823 824 NewGA = new GlobalAlias(SGA->getType(), SGA->getLinkage(), 825 SGA->getName(), DAliasee, Dest); 826 CopyGVAttributes(NewGA, SGA); 827 828 // Proceed to 'common' steps 829 } 830 831 assert(NewGA && "No alias was created in destination module!"); 832 833 // If the symbol table renamed the alias, but it is an externally visible 834 // symbol, DGA must be an global value with internal linkage. Rename it. 835 if (NewGA->getName() != SGA->getName() && 836 !NewGA->hasLocalLinkage()) 837 ForceRenaming(NewGA, SGA->getName()); 838 839 // Remember this mapping so uses in the source module get remapped 840 // later by RemapOperand. 841 ValueMap[SGA] = NewGA; 842 } 843 844 return false; 845} 846 847 848// LinkGlobalInits - Update the initializers in the Dest module now that all 849// globals that may be referenced are in Dest. 850static bool LinkGlobalInits(Module *Dest, const Module *Src, 851 std::map<const Value*, Value*> &ValueMap, 852 std::string *Err) { 853 // Loop over all of the globals in the src module, mapping them over as we go 854 for (Module::const_global_iterator I = Src->global_begin(), 855 E = Src->global_end(); I != E; ++I) { 856 const GlobalVariable *SGV = I; 857 858 if (SGV->hasInitializer()) { // Only process initialized GV's 859 // Figure out what the initializer looks like in the dest module... 860 Constant *SInit = 861 cast<Constant>(RemapOperand(SGV->getInitializer(), ValueMap)); 862 // Grab destination global variable or alias. 863 GlobalValue *DGV = cast<GlobalValue>(ValueMap[SGV]->stripPointerCasts()); 864 865 // If dest if global variable, check that initializers match. 866 if (GlobalVariable *DGVar = dyn_cast<GlobalVariable>(DGV)) { 867 if (DGVar->hasInitializer()) { 868 if (SGV->hasExternalLinkage()) { 869 if (DGVar->getInitializer() != SInit) 870 return Error(Err, "Global Variable Collision on '" + 871 SGV->getName() + 872 "': global variables have different initializers"); 873 } else if (DGVar->mayBeOverridden()) { 874 // Nothing is required, mapped values will take the new global 875 // automatically. 876 } else if (SGV->mayBeOverridden()) { 877 // Nothing is required, mapped values will take the new global 878 // automatically. 879 } else if (DGVar->hasAppendingLinkage()) { 880 assert(0 && "Appending linkage unimplemented!"); 881 } else { 882 assert(0 && "Unknown linkage!"); 883 } 884 } else { 885 // Copy the initializer over now... 886 DGVar->setInitializer(SInit); 887 } 888 } else { 889 // Destination is alias, the only valid situation is when source is 890 // weak. Also, note, that we already checked linkage in LinkGlobals(), 891 // thus we assert here. 892 // FIXME: Should we weaken this assumption, 'dereference' alias and 893 // check for initializer of aliasee? 894 assert(SGV->mayBeOverridden()); 895 } 896 } 897 } 898 return false; 899} 900 901// LinkFunctionProtos - Link the functions together between the two modules, 902// without doing function bodies... this just adds external function prototypes 903// to the Dest function... 904// 905static bool LinkFunctionProtos(Module *Dest, const Module *Src, 906 std::map<const Value*, Value*> &ValueMap, 907 std::string *Err) { 908 ValueSymbolTable &DestSymTab = Dest->getValueSymbolTable(); 909 910 // Loop over all of the functions in the src module, mapping them over 911 for (Module::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) { 912 const Function *SF = I; // SrcFunction 913 GlobalValue *DGV = 0; 914 915 // Check to see if may have to link the function with the global, alias or 916 // function. 917 if (SF->hasName() && !SF->hasLocalLinkage()) 918 DGV = cast_or_null<GlobalValue>(DestSymTab.lookup(SF->getNameStart(), 919 SF->getNameEnd())); 920 921 // If we found a global with the same name in the dest module, but it has 922 // internal linkage, we are really not doing any linkage here. 923 if (DGV && DGV->hasLocalLinkage()) 924 DGV = 0; 925 926 // If types don't agree due to opaque types, try to resolve them. 927 if (DGV && DGV->getType() != SF->getType()) 928 RecursiveResolveTypes(SF->getType(), DGV->getType()); 929 930 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; 931 bool LinkFromSrc = false; 932 if (GetLinkageResult(DGV, SF, NewLinkage, LinkFromSrc, Err)) 933 return true; 934 935 // If there is no linkage to be performed, just bring over SF without 936 // modifying it. 937 if (DGV == 0) { 938 // Function does not already exist, simply insert an function signature 939 // identical to SF into the dest module. 940 Function *NewDF = Function::Create(SF->getFunctionType(), 941 SF->getLinkage(), 942 SF->getName(), Dest); 943 CopyGVAttributes(NewDF, SF); 944 945 // If the LLVM runtime renamed the function, but it is an externally 946 // visible symbol, DF must be an existing function with internal linkage. 947 // Rename it. 948 if (!NewDF->hasLocalLinkage() && NewDF->getName() != SF->getName()) 949 ForceRenaming(NewDF, SF->getName()); 950 951 // ... and remember this mapping... 952 ValueMap[SF] = NewDF; 953 continue; 954 } 955 956 // If the visibilities of the symbols disagree and the destination is a 957 // prototype, take the visibility of its input. 958 if (DGV->isDeclaration()) 959 DGV->setVisibility(SF->getVisibility()); 960 961 if (LinkFromSrc) { 962 if (isa<GlobalAlias>(DGV)) 963 return Error(Err, "Function-Alias Collision on '" + SF->getName() + 964 "': symbol multiple defined"); 965 966 // We have a definition of the same name but different type in the 967 // source module. Copy the prototype to the destination and replace 968 // uses of the destination's prototype with the new prototype. 969 Function *NewDF = Function::Create(SF->getFunctionType(), NewLinkage, 970 SF->getName(), Dest); 971 CopyGVAttributes(NewDF, SF); 972 973 // Any uses of DF need to change to NewDF, with cast 974 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDF, DGV->getType())); 975 976 // DF will conflict with NewDF because they both had the same. We must 977 // erase this now so ForceRenaming doesn't assert because DF might 978 // not have internal linkage. 979 if (GlobalVariable *Var = dyn_cast<GlobalVariable>(DGV)) 980 Var->eraseFromParent(); 981 else 982 cast<Function>(DGV)->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->hasLocalLinkage()) 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 } 995 996 // Not "link from source", keep the one in the DestModule and remap the 997 // input onto it. 998 999 if (isa<GlobalAlias>(DGV)) { 1000 // The only valid mappings are: 1001 // - SF is external declaration, which is effectively a no-op. 1002 // - SF is weak, when we just need to throw SF out. 1003 if (!SF->isDeclaration() && !SF->mayBeOverridden()) 1004 return Error(Err, "Function-Alias Collision on '" + SF->getName() + 1005 "': symbol multiple defined"); 1006 } 1007 1008 // Set calculated linkage 1009 DGV->setLinkage(NewLinkage); 1010 1011 // Make sure to remember this mapping. 1012 ValueMap[SF] = ConstantExpr::getBitCast(DGV, SF->getType()); 1013 } 1014 return false; 1015} 1016 1017// LinkFunctionBody - Copy the source function over into the dest function and 1018// fix up references to values. At this point we know that Dest is an external 1019// function, and that Src is not. 1020static bool LinkFunctionBody(Function *Dest, Function *Src, 1021 std::map<const Value*, Value*> &ValueMap, 1022 std::string *Err) { 1023 assert(Src && Dest && Dest->isDeclaration() && !Src->isDeclaration()); 1024 1025 // Go through and convert function arguments over, remembering the mapping. 1026 Function::arg_iterator DI = Dest->arg_begin(); 1027 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end(); 1028 I != E; ++I, ++DI) { 1029 DI->setName(I->getName()); // Copy the name information over... 1030 1031 // Add a mapping to our local map 1032 ValueMap[I] = DI; 1033 } 1034 1035 // Splice the body of the source function into the dest function. 1036 Dest->getBasicBlockList().splice(Dest->end(), Src->getBasicBlockList()); 1037 1038 // At this point, all of the instructions and values of the function are now 1039 // copied over. The only problem is that they are still referencing values in 1040 // the Source function as operands. Loop through all of the operands of the 1041 // functions and patch them up to point to the local versions... 1042 // 1043 for (Function::iterator BB = Dest->begin(), BE = Dest->end(); BB != BE; ++BB) 1044 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) 1045 for (Instruction::op_iterator OI = I->op_begin(), OE = I->op_end(); 1046 OI != OE; ++OI) 1047 if (!isa<Instruction>(*OI) && !isa<BasicBlock>(*OI)) 1048 *OI = RemapOperand(*OI, ValueMap); 1049 1050 // There is no need to map the arguments anymore. 1051 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end(); 1052 I != E; ++I) 1053 ValueMap.erase(I); 1054 1055 return false; 1056} 1057 1058 1059// LinkFunctionBodies - Link in the function bodies that are defined in the 1060// source module into the DestModule. This consists basically of copying the 1061// function over and fixing up references to values. 1062static bool LinkFunctionBodies(Module *Dest, Module *Src, 1063 std::map<const Value*, Value*> &ValueMap, 1064 std::string *Err) { 1065 1066 // Loop over all of the functions in the src module, mapping them over as we 1067 // go 1068 for (Module::iterator SF = Src->begin(), E = Src->end(); SF != E; ++SF) { 1069 if (!SF->isDeclaration()) { // No body if function is external 1070 Function *DF = dyn_cast<Function>(ValueMap[SF]); // Destination function 1071 1072 // DF not external SF external? 1073 if (DF && DF->isDeclaration()) 1074 // Only provide the function body if there isn't one already. 1075 if (LinkFunctionBody(DF, SF, ValueMap, Err)) 1076 return true; 1077 } 1078 } 1079 return false; 1080} 1081 1082// LinkAppendingVars - If there were any appending global variables, link them 1083// together now. Return true on error. 1084static bool LinkAppendingVars(Module *M, 1085 std::multimap<std::string, GlobalVariable *> &AppendingVars, 1086 std::string *ErrorMsg) { 1087 if (AppendingVars.empty()) return false; // Nothing to do. 1088 1089 // Loop over the multimap of appending vars, processing any variables with the 1090 // same name, forming a new appending global variable with both of the 1091 // initializers merged together, then rewrite references to the old variables 1092 // and delete them. 1093 std::vector<Constant*> Inits; 1094 while (AppendingVars.size() > 1) { 1095 // Get the first two elements in the map... 1096 std::multimap<std::string, 1097 GlobalVariable*>::iterator Second = AppendingVars.begin(), First=Second++; 1098 1099 // If the first two elements are for different names, there is no pair... 1100 // Otherwise there is a pair, so link them together... 1101 if (First->first == Second->first) { 1102 GlobalVariable *G1 = First->second, *G2 = Second->second; 1103 const ArrayType *T1 = cast<ArrayType>(G1->getType()->getElementType()); 1104 const ArrayType *T2 = cast<ArrayType>(G2->getType()->getElementType()); 1105 1106 // Check to see that they two arrays agree on type... 1107 if (T1->getElementType() != T2->getElementType()) 1108 return Error(ErrorMsg, 1109 "Appending variables with different element types need to be linked!"); 1110 if (G1->isConstant() != G2->isConstant()) 1111 return Error(ErrorMsg, 1112 "Appending variables linked with different const'ness!"); 1113 1114 if (G1->getAlignment() != G2->getAlignment()) 1115 return Error(ErrorMsg, 1116 "Appending variables with different alignment need to be linked!"); 1117 1118 if (G1->getVisibility() != G2->getVisibility()) 1119 return Error(ErrorMsg, 1120 "Appending variables with different visibility need to be linked!"); 1121 1122 if (G1->getSection() != G2->getSection()) 1123 return Error(ErrorMsg, 1124 "Appending variables with different section name need to be linked!"); 1125 1126 unsigned NewSize = T1->getNumElements() + T2->getNumElements(); 1127 ArrayType *NewType = ArrayType::get(T1->getElementType(), NewSize); 1128 1129 G1->setName(""); // Clear G1's name in case of a conflict! 1130 1131 // Create the new global variable... 1132 GlobalVariable *NG = 1133 new GlobalVariable(NewType, G1->isConstant(), G1->getLinkage(), 1134 /*init*/0, First->first, M, G1->isThreadLocal(), 1135 G1->getType()->getAddressSpace()); 1136 1137 // Propagate alignment, visibility and section info. 1138 CopyGVAttributes(NG, G1); 1139 1140 // Merge the initializer... 1141 Inits.reserve(NewSize); 1142 if (ConstantArray *I = dyn_cast<ConstantArray>(G1->getInitializer())) { 1143 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i) 1144 Inits.push_back(I->getOperand(i)); 1145 } else { 1146 assert(isa<ConstantAggregateZero>(G1->getInitializer())); 1147 Constant *CV = Constant::getNullValue(T1->getElementType()); 1148 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i) 1149 Inits.push_back(CV); 1150 } 1151 if (ConstantArray *I = dyn_cast<ConstantArray>(G2->getInitializer())) { 1152 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i) 1153 Inits.push_back(I->getOperand(i)); 1154 } else { 1155 assert(isa<ConstantAggregateZero>(G2->getInitializer())); 1156 Constant *CV = Constant::getNullValue(T2->getElementType()); 1157 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i) 1158 Inits.push_back(CV); 1159 } 1160 NG->setInitializer(ConstantArray::get(NewType, Inits)); 1161 Inits.clear(); 1162 1163 // Replace any uses of the two global variables with uses of the new 1164 // global... 1165 1166 // FIXME: This should rewrite simple/straight-forward uses such as 1167 // getelementptr instructions to not use the Cast! 1168 G1->replaceAllUsesWith(ConstantExpr::getBitCast(NG, G1->getType())); 1169 G2->replaceAllUsesWith(ConstantExpr::getBitCast(NG, G2->getType())); 1170 1171 // Remove the two globals from the module now... 1172 M->getGlobalList().erase(G1); 1173 M->getGlobalList().erase(G2); 1174 1175 // Put the new global into the AppendingVars map so that we can handle 1176 // linking of more than two vars... 1177 Second->second = NG; 1178 } 1179 AppendingVars.erase(First); 1180 } 1181 1182 return false; 1183} 1184 1185static bool ResolveAliases(Module *Dest) { 1186 for (Module::alias_iterator I = Dest->alias_begin(), E = Dest->alias_end(); 1187 I != E; ++I) 1188 if (const GlobalValue *GV = I->resolveAliasedGlobal()) 1189 if (GV != I && !GV->isDeclaration()) 1190 I->replaceAllUsesWith(const_cast<GlobalValue*>(GV)); 1191 1192 return false; 1193} 1194 1195// LinkModules - This function links two modules together, with the resulting 1196// left module modified to be the composite of the two input modules. If an 1197// error occurs, true is returned and ErrorMsg (if not null) is set to indicate 1198// the problem. Upon failure, the Dest module could be in a modified state, and 1199// shouldn't be relied on to be consistent. 1200bool 1201Linker::LinkModules(Module *Dest, Module *Src, std::string *ErrorMsg) { 1202 assert(Dest != 0 && "Invalid Destination module"); 1203 assert(Src != 0 && "Invalid Source Module"); 1204 1205 if (Dest->getDataLayout().empty()) { 1206 if (!Src->getDataLayout().empty()) { 1207 Dest->setDataLayout(Src->getDataLayout()); 1208 } else { 1209 std::string DataLayout; 1210 1211 if (Dest->getEndianness() == Module::AnyEndianness) { 1212 if (Src->getEndianness() == Module::BigEndian) 1213 DataLayout.append("E"); 1214 else if (Src->getEndianness() == Module::LittleEndian) 1215 DataLayout.append("e"); 1216 } 1217 1218 if (Dest->getPointerSize() == Module::AnyPointerSize) { 1219 if (Src->getPointerSize() == Module::Pointer64) 1220 DataLayout.append(DataLayout.length() == 0 ? "p:64:64" : "-p:64:64"); 1221 else if (Src->getPointerSize() == Module::Pointer32) 1222 DataLayout.append(DataLayout.length() == 0 ? "p:32:32" : "-p:32:32"); 1223 } 1224 Dest->setDataLayout(DataLayout); 1225 } 1226 } 1227 1228 // Copy the target triple from the source to dest if the dest's is empty. 1229 if (Dest->getTargetTriple().empty() && !Src->getTargetTriple().empty()) 1230 Dest->setTargetTriple(Src->getTargetTriple()); 1231 1232 if (!Src->getDataLayout().empty() && !Dest->getDataLayout().empty() && 1233 Src->getDataLayout() != Dest->getDataLayout()) 1234 cerr << "WARNING: Linking two modules of different data layouts!\n"; 1235 if (!Src->getTargetTriple().empty() && 1236 Dest->getTargetTriple() != Src->getTargetTriple()) 1237 cerr << "WARNING: Linking two modules of different target triples!\n"; 1238 1239 // Append the module inline asm string. 1240 if (!Src->getModuleInlineAsm().empty()) { 1241 if (Dest->getModuleInlineAsm().empty()) 1242 Dest->setModuleInlineAsm(Src->getModuleInlineAsm()); 1243 else 1244 Dest->setModuleInlineAsm(Dest->getModuleInlineAsm()+"\n"+ 1245 Src->getModuleInlineAsm()); 1246 } 1247 1248 // Update the destination module's dependent libraries list with the libraries 1249 // from the source module. There's no opportunity for duplicates here as the 1250 // Module ensures that duplicate insertions are discarded. 1251 for (Module::lib_iterator SI = Src->lib_begin(), SE = Src->lib_end(); 1252 SI != SE; ++SI) 1253 Dest->addLibrary(*SI); 1254 1255 // LinkTypes - Go through the symbol table of the Src module and see if any 1256 // types are named in the src module that are not named in the Dst module. 1257 // Make sure there are no type name conflicts. 1258 if (LinkTypes(Dest, Src, ErrorMsg)) 1259 return true; 1260 1261 // ValueMap - Mapping of values from what they used to be in Src, to what they 1262 // are now in Dest. 1263 std::map<const Value*, Value*> ValueMap; 1264 1265 // AppendingVars - Keep track of global variables in the destination module 1266 // with appending linkage. After the module is linked together, they are 1267 // appended and the module is rewritten. 1268 std::multimap<std::string, GlobalVariable *> AppendingVars; 1269 for (Module::global_iterator I = Dest->global_begin(), E = Dest->global_end(); 1270 I != E; ++I) { 1271 // Add all of the appending globals already in the Dest module to 1272 // AppendingVars. 1273 if (I->hasAppendingLinkage()) 1274 AppendingVars.insert(std::make_pair(I->getName(), I)); 1275 } 1276 1277 // Insert all of the globals in src into the Dest module... without linking 1278 // initializers (which could refer to functions not yet mapped over). 1279 if (LinkGlobals(Dest, Src, ValueMap, AppendingVars, ErrorMsg)) 1280 return true; 1281 1282 // Link the functions together between the two modules, without doing function 1283 // bodies... this just adds external function prototypes to the Dest 1284 // function... We do this so that when we begin processing function bodies, 1285 // all of the global values that may be referenced are available in our 1286 // ValueMap. 1287 if (LinkFunctionProtos(Dest, Src, ValueMap, ErrorMsg)) 1288 return true; 1289 1290 // If there were any alias, link them now. We really need to do this now, 1291 // because all of the aliases that may be referenced need to be available in 1292 // ValueMap 1293 if (LinkAlias(Dest, Src, ValueMap, ErrorMsg)) return true; 1294 1295 // Update the initializers in the Dest module now that all globals that may 1296 // be referenced are in Dest. 1297 if (LinkGlobalInits(Dest, Src, ValueMap, ErrorMsg)) return true; 1298 1299 // Link in the function bodies that are defined in the source module into the 1300 // DestModule. This consists basically of copying the function over and 1301 // fixing up references to values. 1302 if (LinkFunctionBodies(Dest, Src, ValueMap, ErrorMsg)) return true; 1303 1304 // If there were any appending global variables, link them together now. 1305 if (LinkAppendingVars(Dest, AppendingVars, ErrorMsg)) return true; 1306 1307 // Resolve all uses of aliases with aliasees 1308 if (ResolveAliases(Dest)) return true; 1309 1310 // If the source library's module id is in the dependent library list of the 1311 // destination library, remove it since that module is now linked in. 1312 sys::Path modId; 1313 modId.set(Src->getModuleIdentifier()); 1314 if (!modId.isEmpty()) 1315 Dest->removeLibrary(modId.getBasename()); 1316 1317 return false; 1318} 1319 1320// vim: sw=2 1321