LinkModules.cpp revision e3092c94ad2e3af96f37a0a8186149acbbd9700a
1//===- Linker.cpp - Module Linker Implementation --------------------------===// 2// 3// This file implements the LLVM module linker. 4// 5// Specifically, this: 6// * Merges global variables between the two modules 7// * Uninit + Uninit = Init, Init + Uninit = Init, Init + Init = Error if != 8// * Merges functions between two modules 9// 10//===----------------------------------------------------------------------===// 11 12#include "llvm/Transforms/Utils/Linker.h" 13#include "llvm/Module.h" 14#include "llvm/SymbolTable.h" 15#include "llvm/DerivedTypes.h" 16#include "llvm/iOther.h" 17#include "llvm/Constants.h" 18 19// Error - Simple wrapper function to conditionally assign to E and return true. 20// This just makes error return conditions a little bit simpler... 21// 22static inline bool Error(std::string *E, const std::string &Message) { 23 if (E) *E = Message; 24 return true; 25} 26 27// ResolveTypes - Attempt to link the two specified types together. Return true 28// if there is an error and they cannot yet be linked. 29// 30static bool ResolveTypes(const Type *DestTy, const Type *SrcTy, 31 SymbolTable *DestST, const std::string &Name) { 32 if (DestTy == SrcTy) return false; // If already equal, noop 33 34 // Does the type already exist in the module? 35 if (DestTy && !isa<OpaqueType>(DestTy)) { // Yup, the type already exists... 36 if (const OpaqueType *OT = dyn_cast<OpaqueType>(SrcTy)) { 37 const_cast<OpaqueType*>(OT)->refineAbstractTypeTo(DestTy); 38 } else { 39 return true; // Cannot link types... neither is opaque and not-equal 40 } 41 } else { // Type not in dest module. Add it now. 42 if (DestTy) // Type _is_ in module, just opaque... 43 const_cast<OpaqueType*>(cast<OpaqueType>(DestTy)) 44 ->refineAbstractTypeTo(SrcTy); 45 else if (!Name.empty()) 46 DestST->insert(Name, const_cast<Type*>(SrcTy)); 47 } 48 return false; 49} 50 51static const FunctionType *getFT(const PATypeHolder &TH) { 52 return cast<FunctionType>(TH.get()); 53} 54static const StructType *getST(const PATypeHolder &TH) { 55 return cast<StructType>(TH.get()); 56} 57 58// RecursiveResolveTypes - This is just like ResolveTypes, except that it 59// recurses down into derived types, merging the used types if the parent types 60// are compatible. 61// 62static bool RecursiveResolveTypesI(const PATypeHolder &DestTy, 63 const PATypeHolder &SrcTy, 64 SymbolTable *DestST, const std::string &Name, 65 std::vector<std::pair<PATypeHolder, PATypeHolder> > &Pointers) { 66 const Type *SrcTyT = SrcTy.get(); 67 const Type *DestTyT = DestTy.get(); 68 if (DestTyT == SrcTyT) return false; // If already equal, noop 69 70 // If we found our opaque type, resolve it now! 71 if (isa<OpaqueType>(DestTyT) || isa<OpaqueType>(SrcTyT)) 72 return ResolveTypes(DestTyT, SrcTyT, DestST, Name); 73 74 // Two types cannot be resolved together if they are of different primitive 75 // type. For example, we cannot resolve an int to a float. 76 if (DestTyT->getPrimitiveID() != SrcTyT->getPrimitiveID()) return true; 77 78 // Otherwise, resolve the used type used by this derived type... 79 switch (DestTyT->getPrimitiveID()) { 80 case Type::FunctionTyID: { 81 if (cast<FunctionType>(DestTyT)->isVarArg() != 82 cast<FunctionType>(SrcTyT)->isVarArg()) 83 return true; 84 for (unsigned i = 0, e = getFT(DestTy)->getNumContainedTypes(); i != e; ++i) 85 if (RecursiveResolveTypesI(getFT(DestTy)->getContainedType(i), 86 getFT(SrcTy)->getContainedType(i), DestST, "", 87 Pointers)) 88 return true; 89 return false; 90 } 91 case Type::StructTyID: { 92 if (getST(DestTy)->getNumContainedTypes() != 93 getST(SrcTy)->getNumContainedTypes()) return 1; 94 for (unsigned i = 0, e = getST(DestTy)->getNumContainedTypes(); i != e; ++i) 95 if (RecursiveResolveTypesI(getST(DestTy)->getContainedType(i), 96 getST(SrcTy)->getContainedType(i), DestST, "", 97 Pointers)) 98 return true; 99 return false; 100 } 101 case Type::ArrayTyID: { 102 const ArrayType *DAT = cast<ArrayType>(DestTy.get()); 103 const ArrayType *SAT = cast<ArrayType>(SrcTy.get()); 104 if (DAT->getNumElements() != SAT->getNumElements()) return true; 105 return RecursiveResolveTypesI(DAT->getElementType(), SAT->getElementType(), 106 DestST, "", Pointers); 107 } 108 case Type::PointerTyID: { 109 // If this is a pointer type, check to see if we have already seen it. If 110 // so, we are in a recursive branch. Cut off the search now. We cannot use 111 // an associative container for this search, because the type pointers (keys 112 // in the container) change whenever types get resolved... 113 // 114 for (unsigned i = 0, e = Pointers.size(); i != e; ++i) 115 if (Pointers[i].first == DestTy) 116 return Pointers[i].second != SrcTy; 117 118 // Otherwise, add the current pointers to the vector to stop recursion on 119 // this pair. 120 Pointers.push_back(std::make_pair(DestTyT, SrcTyT)); 121 bool Result = 122 RecursiveResolveTypesI(cast<PointerType>(DestTy.get())->getElementType(), 123 cast<PointerType>(SrcTy.get())->getElementType(), 124 DestST, "", Pointers); 125 Pointers.pop_back(); 126 return Result; 127 } 128 default: assert(0 && "Unexpected type!"); return true; 129 } 130} 131 132static bool RecursiveResolveTypes(const PATypeHolder &DestTy, 133 const PATypeHolder &SrcTy, 134 SymbolTable *DestST, const std::string &Name){ 135 std::vector<std::pair<PATypeHolder, PATypeHolder> > PointerTypes; 136 return RecursiveResolveTypesI(DestTy, SrcTy, DestST, Name, PointerTypes); 137} 138 139 140// LinkTypes - Go through the symbol table of the Src module and see if any 141// types are named in the src module that are not named in the Dst module. 142// Make sure there are no type name conflicts. 143// 144static bool LinkTypes(Module *Dest, const Module *Src, std::string *Err) { 145 SymbolTable *DestST = &Dest->getSymbolTable(); 146 const SymbolTable *SrcST = &Src->getSymbolTable(); 147 148 // Look for a type plane for Type's... 149 SymbolTable::const_iterator PI = SrcST->find(Type::TypeTy); 150 if (PI == SrcST->end()) return false; // No named types, do nothing. 151 152 // Some types cannot be resolved immediately becuse they depend on other types 153 // being resolved to each other first. This contains a list of types we are 154 // waiting to recheck. 155 std::vector<std::string> DelayedTypesToResolve; 156 157 const SymbolTable::VarMap &VM = PI->second; 158 for (SymbolTable::type_const_iterator I = VM.begin(), E = VM.end(); 159 I != E; ++I) { 160 const std::string &Name = I->first; 161 Type *RHS = cast<Type>(I->second); 162 163 // Check to see if this type name is already in the dest module... 164 Type *Entry = cast_or_null<Type>(DestST->lookup(Type::TypeTy, Name)); 165 166 if (ResolveTypes(Entry, RHS, DestST, Name)) { 167 // They look different, save the types 'till later to resolve. 168 DelayedTypesToResolve.push_back(Name); 169 } 170 } 171 172 // Iteratively resolve types while we can... 173 while (!DelayedTypesToResolve.empty()) { 174 // Loop over all of the types, attempting to resolve them if possible... 175 unsigned OldSize = DelayedTypesToResolve.size(); 176 177 // Try direct resolution by name... 178 for (unsigned i = 0; i != DelayedTypesToResolve.size(); ++i) { 179 const std::string &Name = DelayedTypesToResolve[i]; 180 Type *T1 = cast<Type>(VM.find(Name)->second); 181 Type *T2 = cast<Type>(DestST->lookup(Type::TypeTy, Name)); 182 if (!ResolveTypes(T2, T1, DestST, Name)) { 183 // We are making progress! 184 DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i); 185 --i; 186 } 187 } 188 189 // Did we not eliminate any types? 190 if (DelayedTypesToResolve.size() == OldSize) { 191 // Attempt to resolve subelements of types. This allows us to merge these 192 // two types: { int* } and { opaque* } 193 for (unsigned i = 0, e = DelayedTypesToResolve.size(); i != e; ++i) { 194 const std::string &Name = DelayedTypesToResolve[i]; 195 PATypeHolder T1(cast<Type>(VM.find(Name)->second)); 196 PATypeHolder T2(cast<Type>(DestST->lookup(Type::TypeTy, Name))); 197 198 if (!RecursiveResolveTypes(T2, T1, DestST, Name)) { 199 // We are making progress! 200 DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i); 201 202 // Go back to the main loop, perhaps we can resolve directly by name 203 // now... 204 break; 205 } 206 } 207 208 // If we STILL cannot resolve the types, then there is something wrong. 209 // Report the error. 210 if (DelayedTypesToResolve.size() == OldSize) { 211 // Build up an error message of all of the mismatched types. 212 std::string ErrorMessage; 213 for (unsigned i = 0, e = DelayedTypesToResolve.size(); i != e; ++i) { 214 const std::string &Name = DelayedTypesToResolve[i]; 215 const Type *T1 = cast<Type>(VM.find(Name)->second); 216 const Type *T2 = cast<Type>(DestST->lookup(Type::TypeTy, Name)); 217 ErrorMessage += " Type named '" + Name + 218 "' conflicts.\n Src='" + T1->getDescription() + 219 "'.\n Dest='" + T2->getDescription() + "'\n"; 220 } 221 return Error(Err, "Type conflict between types in modules:\n" + 222 ErrorMessage); 223 } 224 } 225 } 226 227 228 return false; 229} 230 231static void PrintMap(const std::map<const Value*, Value*> &M) { 232 for (std::map<const Value*, Value*>::const_iterator I = M.begin(), E =M.end(); 233 I != E; ++I) { 234 std::cerr << " Fr: " << (void*)I->first << " "; 235 I->first->dump(); 236 std::cerr << " To: " << (void*)I->second << " "; 237 I->second->dump(); 238 std::cerr << "\n"; 239 } 240} 241 242 243// RemapOperand - Use LocalMap and GlobalMap to convert references from one 244// module to another. This is somewhat sophisticated in that it can 245// automatically handle constant references correctly as well... 246// 247static Value *RemapOperand(const Value *In, 248 std::map<const Value*, Value*> &LocalMap, 249 std::map<const Value*, Value*> *GlobalMap) { 250 std::map<const Value*,Value*>::const_iterator I = LocalMap.find(In); 251 if (I != LocalMap.end()) return I->second; 252 253 if (GlobalMap) { 254 I = GlobalMap->find(In); 255 if (I != GlobalMap->end()) return I->second; 256 } 257 258 // Check to see if it's a constant that we are interesting in transforming... 259 if (const Constant *CPV = dyn_cast<Constant>(In)) { 260 if (!isa<DerivedType>(CPV->getType()) && !isa<ConstantExpr>(CPV)) 261 return const_cast<Constant*>(CPV); // Simple constants stay identical... 262 263 Constant *Result = 0; 264 265 if (const ConstantArray *CPA = dyn_cast<ConstantArray>(CPV)) { 266 const std::vector<Use> &Ops = CPA->getValues(); 267 std::vector<Constant*> Operands(Ops.size()); 268 for (unsigned i = 0, e = Ops.size(); i != e; ++i) 269 Operands[i] = 270 cast<Constant>(RemapOperand(Ops[i], LocalMap, GlobalMap)); 271 Result = ConstantArray::get(cast<ArrayType>(CPA->getType()), Operands); 272 } else if (const ConstantStruct *CPS = dyn_cast<ConstantStruct>(CPV)) { 273 const std::vector<Use> &Ops = CPS->getValues(); 274 std::vector<Constant*> Operands(Ops.size()); 275 for (unsigned i = 0; i < Ops.size(); ++i) 276 Operands[i] = 277 cast<Constant>(RemapOperand(Ops[i], LocalMap, GlobalMap)); 278 Result = ConstantStruct::get(cast<StructType>(CPS->getType()), Operands); 279 } else if (isa<ConstantPointerNull>(CPV)) { 280 Result = const_cast<Constant*>(CPV); 281 } else if (const ConstantPointerRef *CPR = 282 dyn_cast<ConstantPointerRef>(CPV)) { 283 Value *V = RemapOperand(CPR->getValue(), LocalMap, GlobalMap); 284 Result = ConstantPointerRef::get(cast<GlobalValue>(V)); 285 } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CPV)) { 286 if (CE->getOpcode() == Instruction::GetElementPtr) { 287 Value *Ptr = RemapOperand(CE->getOperand(0), LocalMap, GlobalMap); 288 std::vector<Constant*> Indices; 289 Indices.reserve(CE->getNumOperands()-1); 290 for (unsigned i = 1, e = CE->getNumOperands(); i != e; ++i) 291 Indices.push_back(cast<Constant>(RemapOperand(CE->getOperand(i), 292 LocalMap, GlobalMap))); 293 294 Result = ConstantExpr::getGetElementPtr(cast<Constant>(Ptr), Indices); 295 } else if (CE->getNumOperands() == 1) { 296 // Cast instruction 297 assert(CE->getOpcode() == Instruction::Cast); 298 Value *V = RemapOperand(CE->getOperand(0), LocalMap, GlobalMap); 299 Result = ConstantExpr::getCast(cast<Constant>(V), CE->getType()); 300 } else if (CE->getNumOperands() == 2) { 301 // Binary operator... 302 Value *V1 = RemapOperand(CE->getOperand(0), LocalMap, GlobalMap); 303 Value *V2 = RemapOperand(CE->getOperand(1), LocalMap, GlobalMap); 304 305 Result = ConstantExpr::get(CE->getOpcode(), cast<Constant>(V1), 306 cast<Constant>(V2)); 307 } else { 308 assert(0 && "Unknown constant expr type!"); 309 } 310 311 } else { 312 assert(0 && "Unknown type of derived type constant value!"); 313 } 314 315 // Cache the mapping in our local map structure... 316 if (GlobalMap) 317 GlobalMap->insert(std::make_pair(In, Result)); 318 else 319 LocalMap.insert(std::make_pair(In, Result)); 320 return Result; 321 } 322 323 std::cerr << "XXX LocalMap: \n"; 324 PrintMap(LocalMap); 325 326 if (GlobalMap) { 327 std::cerr << "XXX GlobalMap: \n"; 328 PrintMap(*GlobalMap); 329 } 330 331 std::cerr << "Couldn't remap value: " << (void*)In << " " << *In << "\n"; 332 assert(0 && "Couldn't remap value!"); 333 return 0; 334} 335 336/// FindGlobalNamed - Look in the specified symbol table for a global with the 337/// specified name and type. If an exactly matching global does not exist, see 338/// if there is a global which is "type compatible" with the specified 339/// name/type. This allows us to resolve things like '%x = global int*' with 340/// '%x = global opaque*'. 341/// 342static GlobalValue *FindGlobalNamed(const std::string &Name, const Type *Ty, 343 SymbolTable *ST) { 344 // See if an exact match exists in the symbol table... 345 if (Value *V = ST->lookup(Ty, Name)) return cast<GlobalValue>(V); 346 347 // It doesn't exist exactly, scan through all of the type planes in the symbol 348 // table, checking each of them for a type-compatible version. 349 // 350 for (SymbolTable::iterator I = ST->begin(), E = ST->end(); I != E; ++I) { 351 SymbolTable::VarMap &VM = I->second; 352 // Does this type plane contain an entry with the specified name? 353 SymbolTable::type_iterator TI = VM.find(Name); 354 if (TI != VM.end()) { 355 // Determine whether we can fold the two types together, resolving them. 356 // If so, we can use this value. 357 if (!RecursiveResolveTypes(Ty, I->first, ST, "")) 358 return cast<GlobalValue>(TI->second); 359 } 360 } 361 return 0; // Otherwise, nothing could be found. 362} 363 364 365// LinkGlobals - Loop through the global variables in the src module and merge 366// them into the dest module. 367// 368static bool LinkGlobals(Module *Dest, const Module *Src, 369 std::map<const Value*, Value*> &ValueMap, 370 std::multimap<std::string, GlobalVariable *> &AppendingVars, 371 std::string *Err) { 372 // We will need a module level symbol table if the src module has a module 373 // level symbol table... 374 SymbolTable *ST = (SymbolTable*)&Dest->getSymbolTable(); 375 376 // Loop over all of the globals in the src module, mapping them over as we go 377 // 378 for (Module::const_giterator I = Src->gbegin(), E = Src->gend(); I != E; ++I){ 379 const GlobalVariable *SGV = I; 380 GlobalVariable *DGV = 0; 381 if (SGV->hasName()) { 382 // A same named thing is a global variable, because the only two things 383 // that may be in a module level symbol table are Global Vars and 384 // Functions, and they both have distinct, nonoverlapping, possible types. 385 // 386 DGV = cast_or_null<GlobalVariable>(FindGlobalNamed(SGV->getName(), 387 SGV->getType(), ST)); 388 } 389 390 assert(SGV->hasInitializer() || SGV->hasExternalLinkage() && 391 "Global must either be external or have an initializer!"); 392 393 bool SGExtern = SGV->isExternal(); 394 bool DGExtern = DGV ? DGV->isExternal() : false; 395 396 if (!DGV || DGV->hasInternalLinkage() || SGV->hasInternalLinkage()) { 397 // No linking to be performed, simply create an identical version of the 398 // symbol over in the dest module... the initializer will be filled in 399 // later by LinkGlobalInits... 400 // 401 GlobalVariable *NewDGV = 402 new GlobalVariable(SGV->getType()->getElementType(), 403 SGV->isConstant(), SGV->getLinkage(), /*init*/0, 404 SGV->getName(), Dest); 405 406 // If the LLVM runtime renamed the global, but it is an externally visible 407 // symbol, DGV must be an existing global with internal linkage. Rename 408 // it. 409 if (NewDGV->getName() != SGV->getName() && !NewDGV->hasInternalLinkage()){ 410 assert(DGV && DGV->getName() == SGV->getName() && 411 DGV->hasInternalLinkage()); 412 DGV->setName(""); 413 NewDGV->setName(SGV->getName()); // Force the name back 414 DGV->setName(SGV->getName()); // This will cause a renaming 415 assert(NewDGV->getName() == SGV->getName() && 416 DGV->getName() != SGV->getName()); 417 } 418 419 // Make sure to remember this mapping... 420 ValueMap.insert(std::make_pair(SGV, NewDGV)); 421 if (SGV->hasAppendingLinkage()) 422 // Keep track that this is an appending variable... 423 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV)); 424 425 } else if (SGV->isExternal()) { 426 // If SGV is external or if both SGV & DGV are external.. Just link the 427 // external globals, we aren't adding anything. 428 ValueMap.insert(std::make_pair(SGV, DGV)); 429 430 } else if (DGV->isExternal()) { // If DGV is external but SGV is not... 431 ValueMap.insert(std::make_pair(SGV, DGV)); 432 DGV->setLinkage(SGV->getLinkage()); // Inherit linkage! 433 } else if (SGV->getLinkage() != DGV->getLinkage()) { 434 return Error(Err, "Global variables named '" + SGV->getName() + 435 "' have different linkage specifiers!"); 436 } else if (SGV->hasExternalLinkage()) { 437 // Allow linking two exactly identical external global variables... 438 if (SGV->isConstant() != DGV->isConstant() || 439 SGV->getInitializer() != DGV->getInitializer()) 440 return Error(Err, "Global Variable Collision on '" + 441 SGV->getType()->getDescription() + " %" + SGV->getName() + 442 "' - Global variables differ in const'ness"); 443 ValueMap.insert(std::make_pair(SGV, DGV)); 444 } else if (SGV->hasLinkOnceLinkage()) { 445 // If the global variable has a name, and that name is already in use in 446 // the Dest module, make sure that the name is a compatible global 447 // variable... 448 // 449 // Check to see if the two GV's have the same Const'ness... 450 if (SGV->isConstant() != DGV->isConstant()) 451 return Error(Err, "Global Variable Collision on '" + 452 SGV->getType()->getDescription() + " %" + SGV->getName() + 453 "' - Global variables differ in const'ness"); 454 455 // Okay, everything is cool, remember the mapping... 456 ValueMap.insert(std::make_pair(SGV, DGV)); 457 } else if (SGV->hasAppendingLinkage()) { 458 // No linking is performed yet. Just insert a new copy of the global, and 459 // keep track of the fact that it is an appending variable in the 460 // AppendingVars map. The name is cleared out so that no linkage is 461 // performed. 462 GlobalVariable *NewDGV = 463 new GlobalVariable(SGV->getType()->getElementType(), 464 SGV->isConstant(), SGV->getLinkage(), /*init*/0, 465 "", Dest); 466 467 // Make sure to remember this mapping... 468 ValueMap.insert(std::make_pair(SGV, NewDGV)); 469 470 // Keep track that this is an appending variable... 471 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV)); 472 } else { 473 assert(0 && "Unknown linkage!"); 474 } 475 } 476 return false; 477} 478 479 480// LinkGlobalInits - Update the initializers in the Dest module now that all 481// globals that may be referenced are in Dest. 482// 483static bool LinkGlobalInits(Module *Dest, const Module *Src, 484 std::map<const Value*, Value*> &ValueMap, 485 std::string *Err) { 486 487 // Loop over all of the globals in the src module, mapping them over as we go 488 // 489 for (Module::const_giterator I = Src->gbegin(), E = Src->gend(); I != E; ++I){ 490 const GlobalVariable *SGV = I; 491 492 if (SGV->hasInitializer()) { // Only process initialized GV's 493 // Figure out what the initializer looks like in the dest module... 494 Constant *SInit = 495 cast<Constant>(RemapOperand(SGV->getInitializer(), ValueMap, 0)); 496 497 GlobalVariable *DGV = cast<GlobalVariable>(ValueMap[SGV]); 498 if (DGV->hasInitializer()) { 499 assert(SGV->getLinkage() == DGV->getLinkage()); 500 if (SGV->hasExternalLinkage()) { 501 if (DGV->getInitializer() != SInit) 502 return Error(Err, "Global Variable Collision on '" + 503 SGV->getType()->getDescription() +"':%"+SGV->getName()+ 504 " - Global variables have different initializers"); 505 } else if (DGV->hasLinkOnceLinkage()) { 506 // Nothing is required, mapped values will take the new global 507 // automatically. 508 } else if (DGV->hasAppendingLinkage()) { 509 assert(0 && "Appending linkage unimplemented!"); 510 } else { 511 assert(0 && "Unknown linkage!"); 512 } 513 } else { 514 // Copy the initializer over now... 515 DGV->setInitializer(SInit); 516 } 517 } 518 } 519 return false; 520} 521 522// LinkFunctionProtos - Link the functions together between the two modules, 523// without doing function bodies... this just adds external function prototypes 524// to the Dest function... 525// 526static bool LinkFunctionProtos(Module *Dest, const Module *Src, 527 std::map<const Value*, Value*> &ValueMap, 528 std::string *Err) { 529 SymbolTable *ST = (SymbolTable*)&Dest->getSymbolTable(); 530 531 // Loop over all of the functions in the src module, mapping them over as we 532 // go 533 // 534 for (Module::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) { 535 const Function *SF = I; // SrcFunction 536 Function *DF = 0; 537 if (SF->hasName()) 538 // The same named thing is a Function, because the only two things 539 // that may be in a module level symbol table are Global Vars and 540 // Functions, and they both have distinct, nonoverlapping, possible types. 541 // 542 DF = cast_or_null<Function>(FindGlobalNamed(SF->getName(), SF->getType(), 543 ST)); 544 545 if (!DF || SF->hasInternalLinkage() || DF->hasInternalLinkage()) { 546 // Function does not already exist, simply insert an function signature 547 // identical to SF into the dest module... 548 Function *NewDF = new Function(SF->getFunctionType(), SF->getLinkage(), 549 SF->getName(), Dest); 550 551 // If the LLVM runtime renamed the function, but it is an externally 552 // visible symbol, DF must be an existing function with internal linkage. 553 // Rename it. 554 if (NewDF->getName() != SF->getName() && !NewDF->hasInternalLinkage()) { 555 assert(DF && DF->getName() == SF->getName() &&DF->hasInternalLinkage()); 556 DF->setName(""); 557 NewDF->setName(SF->getName()); // Force the name back 558 DF->setName(SF->getName()); // This will cause a renaming 559 assert(NewDF->getName() == SF->getName() && 560 DF->getName() != SF->getName()); 561 } 562 563 // ... and remember this mapping... 564 ValueMap.insert(std::make_pair(SF, NewDF)); 565 } else if (SF->isExternal()) { 566 // If SF is external or if both SF & DF are external.. Just link the 567 // external functions, we aren't adding anything. 568 ValueMap.insert(std::make_pair(SF, DF)); 569 } else if (DF->isExternal()) { // If DF is external but SF is not... 570 // Link the external functions, update linkage qualifiers 571 ValueMap.insert(std::make_pair(SF, DF)); 572 DF->setLinkage(SF->getLinkage()); 573 574 } else if (SF->getLinkage() != DF->getLinkage()) { 575 return Error(Err, "Functions named '" + SF->getName() + 576 "' have different linkage specifiers!"); 577 } else if (SF->hasExternalLinkage()) { 578 // The function is defined in both modules!! 579 return Error(Err, "Function '" + 580 SF->getFunctionType()->getDescription() + "':\"" + 581 SF->getName() + "\" - Function is already defined!"); 582 } else if (SF->hasLinkOnceLinkage()) { 583 // Completely ignore the source function. 584 ValueMap.insert(std::make_pair(SF, DF)); 585 } else { 586 assert(0 && "Unknown linkage configuration found!"); 587 } 588 } 589 return false; 590} 591 592// LinkFunctionBody - Copy the source function over into the dest function and 593// fix up references to values. At this point we know that Dest is an external 594// function, and that Src is not. 595// 596static bool LinkFunctionBody(Function *Dest, const Function *Src, 597 std::map<const Value*, Value*> &GlobalMap, 598 std::string *Err) { 599 assert(Src && Dest && Dest->isExternal() && !Src->isExternal()); 600 std::map<const Value*, Value*> LocalMap; // Map for function local values 601 602 // Go through and convert function arguments over... 603 Function::aiterator DI = Dest->abegin(); 604 for (Function::const_aiterator I = Src->abegin(), E = Src->aend(); 605 I != E; ++I, ++DI) { 606 DI->setName(I->getName()); // Copy the name information over... 607 608 // Add a mapping to our local map 609 LocalMap.insert(std::make_pair(I, DI)); 610 } 611 612 // Loop over all of the basic blocks, copying the instructions over... 613 // 614 for (Function::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) { 615 // Create new basic block and add to mapping and the Dest function... 616 BasicBlock *DBB = new BasicBlock(I->getName(), Dest); 617 LocalMap.insert(std::make_pair(I, DBB)); 618 619 // Loop over all of the instructions in the src basic block, copying them 620 // over. Note that this is broken in a strict sense because the cloned 621 // instructions will still be referencing values in the Src module, not 622 // the remapped values. In our case, however, we will not get caught and 623 // so we can delay patching the values up until later... 624 // 625 for (BasicBlock::const_iterator II = I->begin(), IE = I->end(); 626 II != IE; ++II) { 627 Instruction *DI = II->clone(); 628 DI->setName(II->getName()); 629 DBB->getInstList().push_back(DI); 630 LocalMap.insert(std::make_pair(II, DI)); 631 } 632 } 633 634 // At this point, all of the instructions and values of the function are now 635 // copied over. The only problem is that they are still referencing values in 636 // the Source function as operands. Loop through all of the operands of the 637 // functions and patch them up to point to the local versions... 638 // 639 for (Function::iterator BB = Dest->begin(), BE = Dest->end(); BB != BE; ++BB) 640 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) 641 for (Instruction::op_iterator OI = I->op_begin(), OE = I->op_end(); 642 OI != OE; ++OI) 643 *OI = RemapOperand(*OI, LocalMap, &GlobalMap); 644 645 return false; 646} 647 648 649// LinkFunctionBodies - Link in the function bodies that are defined in the 650// source module into the DestModule. This consists basically of copying the 651// function over and fixing up references to values. 652// 653static bool LinkFunctionBodies(Module *Dest, const Module *Src, 654 std::map<const Value*, Value*> &ValueMap, 655 std::string *Err) { 656 657 // Loop over all of the functions in the src module, mapping them over as we 658 // go 659 // 660 for (Module::const_iterator SF = Src->begin(), E = Src->end(); SF != E; ++SF){ 661 if (!SF->isExternal()) { // No body if function is external 662 Function *DF = cast<Function>(ValueMap[SF]); // Destination function 663 664 // DF not external SF external? 665 if (!DF->isExternal()) { 666 if (DF->hasLinkOnceLinkage()) continue; // No relinkage for link-once! 667 if (Err) 668 *Err = "Function '" + (SF->hasName() ? SF->getName() :std::string("")) 669 + "' body multiply defined!"; 670 return true; 671 } 672 673 if (LinkFunctionBody(DF, SF, ValueMap, Err)) return true; 674 } 675 } 676 return false; 677} 678 679// LinkAppendingVars - If there were any appending global variables, link them 680// together now. Return true on error. 681// 682static bool LinkAppendingVars(Module *M, 683 std::multimap<std::string, GlobalVariable *> &AppendingVars, 684 std::string *ErrorMsg) { 685 if (AppendingVars.empty()) return false; // Nothing to do. 686 687 // Loop over the multimap of appending vars, processing any variables with the 688 // same name, forming a new appending global variable with both of the 689 // initializers merged together, then rewrite references to the old variables 690 // and delete them. 691 // 692 std::vector<Constant*> Inits; 693 while (AppendingVars.size() > 1) { 694 // Get the first two elements in the map... 695 std::multimap<std::string, 696 GlobalVariable*>::iterator Second = AppendingVars.begin(), First=Second++; 697 698 // If the first two elements are for different names, there is no pair... 699 // Otherwise there is a pair, so link them together... 700 if (First->first == Second->first) { 701 GlobalVariable *G1 = First->second, *G2 = Second->second; 702 const ArrayType *T1 = cast<ArrayType>(G1->getType()->getElementType()); 703 const ArrayType *T2 = cast<ArrayType>(G2->getType()->getElementType()); 704 705 // Check to see that they two arrays agree on type... 706 if (T1->getElementType() != T2->getElementType()) 707 return Error(ErrorMsg, 708 "Appending variables with different element types need to be linked!"); 709 if (G1->isConstant() != G2->isConstant()) 710 return Error(ErrorMsg, 711 "Appending variables linked with different const'ness!"); 712 713 unsigned NewSize = T1->getNumElements() + T2->getNumElements(); 714 ArrayType *NewType = ArrayType::get(T1->getElementType(), NewSize); 715 716 // Create the new global variable... 717 GlobalVariable *NG = 718 new GlobalVariable(NewType, G1->isConstant(), G1->getLinkage(), 719 /*init*/0, First->first, M); 720 721 // Merge the initializer... 722 Inits.reserve(NewSize); 723 ConstantArray *I = cast<ConstantArray>(G1->getInitializer()); 724 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i) 725 Inits.push_back(cast<Constant>(I->getValues()[i])); 726 I = cast<ConstantArray>(G2->getInitializer()); 727 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i) 728 Inits.push_back(cast<Constant>(I->getValues()[i])); 729 NG->setInitializer(ConstantArray::get(NewType, Inits)); 730 Inits.clear(); 731 732 // Replace any uses of the two global variables with uses of the new 733 // global... 734 735 // FIXME: This should rewrite simple/straight-forward uses such as 736 // getelementptr instructions to not use the Cast! 737 ConstantPointerRef *NGCP = ConstantPointerRef::get(NG); 738 G1->replaceAllUsesWith(ConstantExpr::getCast(NGCP, G1->getType())); 739 G2->replaceAllUsesWith(ConstantExpr::getCast(NGCP, G2->getType())); 740 741 // Remove the two globals from the module now... 742 M->getGlobalList().erase(G1); 743 M->getGlobalList().erase(G2); 744 745 // Put the new global into the AppendingVars map so that we can handle 746 // linking of more than two vars... 747 Second->second = NG; 748 } 749 AppendingVars.erase(First); 750 } 751 752 return false; 753} 754 755 756// LinkModules - This function links two modules together, with the resulting 757// left module modified to be the composite of the two input modules. If an 758// error occurs, true is returned and ErrorMsg (if not null) is set to indicate 759// the problem. Upon failure, the Dest module could be in a modified state, and 760// shouldn't be relied on to be consistent. 761// 762bool LinkModules(Module *Dest, const Module *Src, std::string *ErrorMsg) { 763 if (Dest->getEndianness() != Src->getEndianness()) 764 std::cerr << "WARNING: Linking two modules of different endianness!\n"; 765 if (Dest->getPointerSize() != Src->getPointerSize()) 766 std::cerr << "WARNING: Linking two modules of different pointer size!\n"; 767 768 // LinkTypes - Go through the symbol table of the Src module and see if any 769 // types are named in the src module that are not named in the Dst module. 770 // Make sure there are no type name conflicts. 771 // 772 if (LinkTypes(Dest, Src, ErrorMsg)) return true; 773 774 // ValueMap - Mapping of values from what they used to be in Src, to what they 775 // are now in Dest. 776 // 777 std::map<const Value*, Value*> ValueMap; 778 779 // AppendingVars - Keep track of global variables in the destination module 780 // with appending linkage. After the module is linked together, they are 781 // appended and the module is rewritten. 782 // 783 std::multimap<std::string, GlobalVariable *> AppendingVars; 784 785 // Add all of the appending globals already in the Dest module to 786 // AppendingVars. 787 for (Module::giterator I = Dest->gbegin(), E = Dest->gend(); I != E; ++I) 788 if (I->hasAppendingLinkage()) 789 AppendingVars.insert(std::make_pair(I->getName(), I)); 790 791 // Insert all of the globals in src into the Dest module... without linking 792 // initializers (which could refer to functions not yet mapped over). 793 // 794 if (LinkGlobals(Dest, Src, ValueMap, AppendingVars, ErrorMsg)) return true; 795 796 // Link the functions together between the two modules, without doing function 797 // bodies... this just adds external function prototypes to the Dest 798 // function... We do this so that when we begin processing function bodies, 799 // all of the global values that may be referenced are available in our 800 // ValueMap. 801 // 802 if (LinkFunctionProtos(Dest, Src, ValueMap, ErrorMsg)) return true; 803 804 // Update the initializers in the Dest module now that all globals that may 805 // be referenced are in Dest. 806 // 807 if (LinkGlobalInits(Dest, Src, ValueMap, ErrorMsg)) return true; 808 809 // Link in the function bodies that are defined in the source module into the 810 // DestModule. This consists basically of copying the function over and 811 // fixing up references to values. 812 // 813 if (LinkFunctionBodies(Dest, Src, ValueMap, ErrorMsg)) return true; 814 815 // If there were any appending global variables, link them together now. 816 // 817 if (LinkAppendingVars(Dest, AppendingVars, ErrorMsg)) return true; 818 819 return false; 820} 821 822