LinkModules.cpp revision aad2deb17c3e624cae4ebc1ed51fc5264fa1c0b8
1//===- Linker.cpp - Module Linker Implementation --------------------------===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file was developed by the LLVM research group and is distributed under 6// the University of Illinois Open Source 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/Support/Linker.h" 20#include "llvm/Constants.h" 21#include "llvm/DerivedTypes.h" 22#include "llvm/Module.h" 23#include "llvm/SymbolTable.h" 24#include "llvm/Instructions.h" 25#include "llvm/Assembly/Writer.h" 26#include <iostream> 27using namespace llvm; 28 29// Error - Simple wrapper function to conditionally assign to E and return true. 30// This just makes error return conditions a little bit simpler... 31// 32static inline bool Error(std::string *E, const std::string &Message) { 33 if (E) *E = Message; 34 return true; 35} 36 37// 38// Function: ResolveTypes() 39// 40// Description: 41// Attempt to link the two specified types together. 42// 43// Inputs: 44// DestTy - The type to which we wish to resolve. 45// SrcTy - The original type which we want to resolve. 46// Name - The name of the type. 47// 48// Outputs: 49// DestST - The symbol table in which the new type should be placed. 50// 51// Return value: 52// true - There is an error and the types cannot yet be linked. 53// false - No errors. 54// 55static bool ResolveTypes(const Type *DestTy, const Type *SrcTy, 56 SymbolTable *DestST, const std::string &Name) { 57 if (DestTy == SrcTy) return false; // If already equal, noop 58 59 // Does the type already exist in the module? 60 if (DestTy && !isa<OpaqueType>(DestTy)) { // Yup, the type already exists... 61 if (const OpaqueType *OT = dyn_cast<OpaqueType>(SrcTy)) { 62 const_cast<OpaqueType*>(OT)->refineAbstractTypeTo(DestTy); 63 } else { 64 return true; // Cannot link types... neither is opaque and not-equal 65 } 66 } else { // Type not in dest module. Add it now. 67 if (DestTy) // Type _is_ in module, just opaque... 68 const_cast<OpaqueType*>(cast<OpaqueType>(DestTy)) 69 ->refineAbstractTypeTo(SrcTy); 70 else if (!Name.empty()) 71 DestST->insert(Name, const_cast<Type*>(SrcTy)); 72 } 73 return false; 74} 75 76static const FunctionType *getFT(const PATypeHolder &TH) { 77 return cast<FunctionType>(TH.get()); 78} 79static const StructType *getST(const PATypeHolder &TH) { 80 return cast<StructType>(TH.get()); 81} 82 83// RecursiveResolveTypes - This is just like ResolveTypes, except that it 84// recurses down into derived types, merging the used types if the parent types 85// are compatible. 86// 87static bool RecursiveResolveTypesI(const PATypeHolder &DestTy, 88 const PATypeHolder &SrcTy, 89 SymbolTable *DestST, const std::string &Name, 90 std::vector<std::pair<PATypeHolder, PATypeHolder> > &Pointers) { 91 const Type *SrcTyT = SrcTy.get(); 92 const Type *DestTyT = DestTy.get(); 93 if (DestTyT == SrcTyT) return false; // If already equal, noop 94 95 // If we found our opaque type, resolve it now! 96 if (isa<OpaqueType>(DestTyT) || isa<OpaqueType>(SrcTyT)) 97 return ResolveTypes(DestTyT, SrcTyT, DestST, Name); 98 99 // Two types cannot be resolved together if they are of different primitive 100 // type. For example, we cannot resolve an int to a float. 101 if (DestTyT->getTypeID() != SrcTyT->getTypeID()) return true; 102 103 // Otherwise, resolve the used type used by this derived type... 104 switch (DestTyT->getTypeID()) { 105 case Type::FunctionTyID: { 106 if (cast<FunctionType>(DestTyT)->isVarArg() != 107 cast<FunctionType>(SrcTyT)->isVarArg() || 108 cast<FunctionType>(DestTyT)->getNumContainedTypes() != 109 cast<FunctionType>(SrcTyT)->getNumContainedTypes()) 110 return true; 111 for (unsigned i = 0, e = getFT(DestTy)->getNumContainedTypes(); i != e; ++i) 112 if (RecursiveResolveTypesI(getFT(DestTy)->getContainedType(i), 113 getFT(SrcTy)->getContainedType(i), DestST, "", 114 Pointers)) 115 return true; 116 return false; 117 } 118 case Type::StructTyID: { 119 if (getST(DestTy)->getNumContainedTypes() != 120 getST(SrcTy)->getNumContainedTypes()) return 1; 121 for (unsigned i = 0, e = getST(DestTy)->getNumContainedTypes(); i != e; ++i) 122 if (RecursiveResolveTypesI(getST(DestTy)->getContainedType(i), 123 getST(SrcTy)->getContainedType(i), DestST, "", 124 Pointers)) 125 return true; 126 return false; 127 } 128 case Type::ArrayTyID: { 129 const ArrayType *DAT = cast<ArrayType>(DestTy.get()); 130 const ArrayType *SAT = cast<ArrayType>(SrcTy.get()); 131 if (DAT->getNumElements() != SAT->getNumElements()) return true; 132 return RecursiveResolveTypesI(DAT->getElementType(), SAT->getElementType(), 133 DestST, "", Pointers); 134 } 135 case Type::PointerTyID: { 136 // If this is a pointer type, check to see if we have already seen it. If 137 // so, we are in a recursive branch. Cut off the search now. We cannot use 138 // an associative container for this search, because the type pointers (keys 139 // in the container) change whenever types get resolved... 140 // 141 for (unsigned i = 0, e = Pointers.size(); i != e; ++i) 142 if (Pointers[i].first == DestTy) 143 return Pointers[i].second != SrcTy; 144 145 // Otherwise, add the current pointers to the vector to stop recursion on 146 // this pair. 147 Pointers.push_back(std::make_pair(DestTyT, SrcTyT)); 148 bool Result = 149 RecursiveResolveTypesI(cast<PointerType>(DestTy.get())->getElementType(), 150 cast<PointerType>(SrcTy.get())->getElementType(), 151 DestST, "", Pointers); 152 Pointers.pop_back(); 153 return Result; 154 } 155 default: assert(0 && "Unexpected type!"); return true; 156 } 157} 158 159static bool RecursiveResolveTypes(const PATypeHolder &DestTy, 160 const PATypeHolder &SrcTy, 161 SymbolTable *DestST, const std::string &Name){ 162 std::vector<std::pair<PATypeHolder, PATypeHolder> > PointerTypes; 163 return RecursiveResolveTypesI(DestTy, SrcTy, DestST, Name, PointerTypes); 164} 165 166 167// LinkTypes - Go through the symbol table of the Src module and see if any 168// types are named in the src module that are not named in the Dst module. 169// Make sure there are no type name conflicts. 170// 171static bool LinkTypes(Module *Dest, const Module *Src, std::string *Err) { 172 SymbolTable *DestST = &Dest->getSymbolTable(); 173 const SymbolTable *SrcST = &Src->getSymbolTable(); 174 175 // Look for a type plane for Type's... 176 SymbolTable::type_const_iterator TI = SrcST->type_begin(); 177 SymbolTable::type_const_iterator TE = SrcST->type_end(); 178 if (TI == TE) return false; // No named types, do nothing. 179 180 // Some types cannot be resolved immediately because they depend on other 181 // types being resolved to each other first. This contains a list of types we 182 // are waiting to recheck. 183 std::vector<std::string> DelayedTypesToResolve; 184 185 for ( ; TI != TE; ++TI ) { 186 const std::string &Name = TI->first; 187 const Type *RHS = TI->second; 188 189 // Check to see if this type name is already in the dest module... 190 Type *Entry = DestST->lookupType(Name); 191 192 if (ResolveTypes(Entry, RHS, DestST, Name)) { 193 // They look different, save the types 'till later to resolve. 194 DelayedTypesToResolve.push_back(Name); 195 } 196 } 197 198 // Iteratively resolve types while we can... 199 while (!DelayedTypesToResolve.empty()) { 200 // Loop over all of the types, attempting to resolve them if possible... 201 unsigned OldSize = DelayedTypesToResolve.size(); 202 203 // Try direct resolution by name... 204 for (unsigned i = 0; i != DelayedTypesToResolve.size(); ++i) { 205 const std::string &Name = DelayedTypesToResolve[i]; 206 Type *T1 = SrcST->lookupType(Name); 207 Type *T2 = DestST->lookupType(Name); 208 if (!ResolveTypes(T2, T1, DestST, Name)) { 209 // We are making progress! 210 DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i); 211 --i; 212 } 213 } 214 215 // Did we not eliminate any types? 216 if (DelayedTypesToResolve.size() == OldSize) { 217 // Attempt to resolve subelements of types. This allows us to merge these 218 // two types: { int* } and { opaque* } 219 for (unsigned i = 0, e = DelayedTypesToResolve.size(); i != e; ++i) { 220 const std::string &Name = DelayedTypesToResolve[i]; 221 PATypeHolder T1(SrcST->lookupType(Name)); 222 PATypeHolder T2(DestST->lookupType(Name)); 223 224 if (!RecursiveResolveTypes(T2, T1, DestST, Name)) { 225 // We are making progress! 226 DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i); 227 228 // Go back to the main loop, perhaps we can resolve directly by name 229 // now... 230 break; 231 } 232 } 233 234 // If we STILL cannot resolve the types, then there is something wrong. 235 // Report the warning and delete one of the names. 236 if (DelayedTypesToResolve.size() == OldSize) { 237 const std::string &Name = DelayedTypesToResolve.back(); 238 239 const Type *T1 = SrcST->lookupType(Name); 240 const Type *T2 = DestST->lookupType(Name); 241 std::cerr << "WARNING: Type conflict between types named '" << Name 242 << "'.\n Src='"; 243 WriteTypeSymbolic(std::cerr, T1, Src); 244 std::cerr << "'.\n Dest='"; 245 WriteTypeSymbolic(std::cerr, T2, Dest); 246 std::cerr << "'\n"; 247 248 // Remove the symbol name from the destination. 249 DelayedTypesToResolve.pop_back(); 250 } 251 } 252 } 253 254 255 return false; 256} 257 258static void PrintMap(const std::map<const Value*, Value*> &M) { 259 for (std::map<const Value*, Value*>::const_iterator I = M.begin(), E =M.end(); 260 I != E; ++I) { 261 std::cerr << " Fr: " << (void*)I->first << " "; 262 I->first->dump(); 263 std::cerr << " To: " << (void*)I->second << " "; 264 I->second->dump(); 265 std::cerr << "\n"; 266 } 267} 268 269 270// RemapOperand - Use LocalMap and GlobalMap to convert references from one 271// module to another. This is somewhat sophisticated in that it can 272// automatically handle constant references correctly as well... 273// 274static Value *RemapOperand(const Value *In, 275 std::map<const Value*, Value*> &LocalMap, 276 std::map<const Value*, Value*> *GlobalMap) { 277 std::map<const Value*,Value*>::const_iterator I = LocalMap.find(In); 278 if (I != LocalMap.end()) return I->second; 279 280 if (GlobalMap) { 281 I = GlobalMap->find(In); 282 if (I != GlobalMap->end()) return I->second; 283 } 284 285 // Check to see if it's a constant that we are interesting in transforming... 286 if (const Constant *CPV = dyn_cast<Constant>(In)) { 287 if ((!isa<DerivedType>(CPV->getType()) && !isa<ConstantExpr>(CPV)) || 288 isa<ConstantAggregateZero>(CPV)) 289 return const_cast<Constant*>(CPV); // Simple constants stay identical... 290 291 Constant *Result = 0; 292 293 if (const ConstantArray *CPA = dyn_cast<ConstantArray>(CPV)) { 294 std::vector<Constant*> Operands(CPA->getNumOperands()); 295 for (unsigned i = 0, e = CPA->getNumOperands(); i != e; ++i) 296 Operands[i] = 297 cast<Constant>(RemapOperand(CPA->getOperand(i), LocalMap, GlobalMap)); 298 Result = ConstantArray::get(cast<ArrayType>(CPA->getType()), Operands); 299 } else if (const ConstantStruct *CPS = dyn_cast<ConstantStruct>(CPV)) { 300 std::vector<Constant*> Operands(CPS->getNumOperands()); 301 for (unsigned i = 0, e = CPS->getNumOperands(); i != e; ++i) 302 Operands[i] = 303 cast<Constant>(RemapOperand(CPS->getOperand(i), LocalMap, GlobalMap)); 304 Result = ConstantStruct::get(cast<StructType>(CPS->getType()), Operands); 305 } else if (isa<ConstantPointerNull>(CPV)) { 306 Result = const_cast<Constant*>(CPV); 307 } else if (isa<GlobalValue>(CPV)) { 308 Result = cast<Constant>(RemapOperand(CPV, LocalMap, GlobalMap)); 309 } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CPV)) { 310 if (CE->getOpcode() == Instruction::GetElementPtr) { 311 Value *Ptr = RemapOperand(CE->getOperand(0), LocalMap, GlobalMap); 312 std::vector<Constant*> Indices; 313 Indices.reserve(CE->getNumOperands()-1); 314 for (unsigned i = 1, e = CE->getNumOperands(); i != e; ++i) 315 Indices.push_back(cast<Constant>(RemapOperand(CE->getOperand(i), 316 LocalMap, GlobalMap))); 317 318 Result = ConstantExpr::getGetElementPtr(cast<Constant>(Ptr), Indices); 319 } else if (CE->getNumOperands() == 1) { 320 // Cast instruction 321 assert(CE->getOpcode() == Instruction::Cast); 322 Value *V = RemapOperand(CE->getOperand(0), LocalMap, GlobalMap); 323 Result = ConstantExpr::getCast(cast<Constant>(V), CE->getType()); 324 } else if (CE->getNumOperands() == 3) { 325 // Select instruction 326 assert(CE->getOpcode() == Instruction::Select); 327 Value *V1 = RemapOperand(CE->getOperand(0), LocalMap, GlobalMap); 328 Value *V2 = RemapOperand(CE->getOperand(1), LocalMap, GlobalMap); 329 Value *V3 = RemapOperand(CE->getOperand(2), LocalMap, GlobalMap); 330 Result = ConstantExpr::getSelect(cast<Constant>(V1), cast<Constant>(V2), 331 cast<Constant>(V3)); 332 } else if (CE->getNumOperands() == 2) { 333 // Binary operator... 334 Value *V1 = RemapOperand(CE->getOperand(0), LocalMap, GlobalMap); 335 Value *V2 = RemapOperand(CE->getOperand(1), LocalMap, GlobalMap); 336 337 Result = ConstantExpr::get(CE->getOpcode(), cast<Constant>(V1), 338 cast<Constant>(V2)); 339 } else { 340 assert(0 && "Unknown constant expr type!"); 341 } 342 343 } else { 344 assert(0 && "Unknown type of derived type constant value!"); 345 } 346 347 // Cache the mapping in our local map structure... 348 if (GlobalMap) 349 GlobalMap->insert(std::make_pair(In, Result)); 350 else 351 LocalMap.insert(std::make_pair(In, Result)); 352 return Result; 353 } 354 355 std::cerr << "XXX LocalMap: \n"; 356 PrintMap(LocalMap); 357 358 if (GlobalMap) { 359 std::cerr << "XXX GlobalMap: \n"; 360 PrintMap(*GlobalMap); 361 } 362 363 std::cerr << "Couldn't remap value: " << (void*)In << " " << *In << "\n"; 364 assert(0 && "Couldn't remap value!"); 365 return 0; 366} 367 368/// ForceRenaming - The LLVM SymbolTable class autorenames globals that conflict 369/// in the symbol table. This is good for all clients except for us. Go 370/// through the trouble to force this back. 371static void ForceRenaming(GlobalValue *GV, const std::string &Name) { 372 assert(GV->getName() != Name && "Can't force rename to self"); 373 SymbolTable &ST = GV->getParent()->getSymbolTable(); 374 375 // If there is a conflict, rename the conflict. 376 Value *ConflictVal = ST.lookup(GV->getType(), Name); 377 assert(ConflictVal&&"Why do we have to force rename if there is no conflic?"); 378 GlobalValue *ConflictGV = cast<GlobalValue>(ConflictVal); 379 assert(ConflictGV->hasInternalLinkage() && 380 "Not conflicting with a static global, should link instead!"); 381 382 ConflictGV->setName(""); // Eliminate the conflict 383 GV->setName(Name); // Force the name back 384 ConflictGV->setName(Name); // This will cause ConflictGV to get renamed 385 assert(GV->getName() == Name && ConflictGV->getName() != Name && 386 "ForceRenaming didn't work"); 387} 388 389 390// LinkGlobals - Loop through the global variables in the src module and merge 391// them into the dest module. 392// 393static bool LinkGlobals(Module *Dest, const Module *Src, 394 std::map<const Value*, Value*> &ValueMap, 395 std::multimap<std::string, GlobalVariable *> &AppendingVars, 396 std::map<std::string, GlobalValue*> &GlobalsByName, 397 std::string *Err) { 398 // We will need a module level symbol table if the src module has a module 399 // level symbol table... 400 SymbolTable *ST = (SymbolTable*)&Dest->getSymbolTable(); 401 402 // Loop over all of the globals in the src module, mapping them over as we go 403 // 404 for (Module::const_giterator I = Src->gbegin(), E = Src->gend(); I != E; ++I){ 405 const GlobalVariable *SGV = I; 406 GlobalVariable *DGV = 0; 407 // Check to see if may have to link the global. 408 if (SGV->hasName() && !SGV->hasInternalLinkage()) 409 if (!(DGV = Dest->getGlobalVariable(SGV->getName(), 410 SGV->getType()->getElementType()))) { 411 std::map<std::string, GlobalValue*>::iterator EGV = 412 GlobalsByName.find(SGV->getName()); 413 if (EGV != GlobalsByName.end()) 414 DGV = dyn_cast<GlobalVariable>(EGV->second); 415 if (DGV && RecursiveResolveTypes(SGV->getType(), DGV->getType(), ST, "")) 416 DGV = 0; // FIXME: gross. 417 } 418 419 assert(SGV->hasInitializer() || SGV->hasExternalLinkage() && 420 "Global must either be external or have an initializer!"); 421 422 bool SGExtern = SGV->isExternal(); 423 bool DGExtern = DGV ? DGV->isExternal() : false; 424 425 if (!DGV || DGV->hasInternalLinkage() || SGV->hasInternalLinkage()) { 426 // No linking to be performed, simply create an identical version of the 427 // symbol over in the dest module... the initializer will be filled in 428 // later by LinkGlobalInits... 429 // 430 GlobalVariable *NewDGV = 431 new GlobalVariable(SGV->getType()->getElementType(), 432 SGV->isConstant(), SGV->getLinkage(), /*init*/0, 433 SGV->getName(), Dest); 434 435 // If the LLVM runtime renamed the global, but it is an externally visible 436 // symbol, DGV must be an existing global with internal linkage. Rename 437 // it. 438 if (NewDGV->getName() != SGV->getName() && !NewDGV->hasInternalLinkage()) 439 ForceRenaming(NewDGV, SGV->getName()); 440 441 // Make sure to remember this mapping... 442 ValueMap.insert(std::make_pair(SGV, NewDGV)); 443 if (SGV->hasAppendingLinkage()) 444 // Keep track that this is an appending variable... 445 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV)); 446 447 } else if (SGV->isExternal()) { 448 // If SGV is external or if both SGV & DGV are external.. Just link the 449 // external globals, we aren't adding anything. 450 ValueMap.insert(std::make_pair(SGV, DGV)); 451 452 } else if (DGV->isExternal()) { // If DGV is external but SGV is not... 453 ValueMap.insert(std::make_pair(SGV, DGV)); 454 DGV->setLinkage(SGV->getLinkage()); // Inherit linkage! 455 } else if (SGV->hasWeakLinkage() || SGV->hasLinkOnceLinkage()) { 456 // At this point we know that DGV has LinkOnce, Appending, Weak, or 457 // External linkage. If DGV is Appending, this is an error. 458 if (DGV->hasAppendingLinkage()) 459 return Error(Err, "Linking globals named '" + SGV->getName() + 460 " ' with 'weak' and 'appending' linkage is not allowed!"); 461 462 if (SGV->isConstant() != DGV->isConstant()) 463 return Error(Err, "Global Variable Collision on '" + 464 SGV->getType()->getDescription() + " %" + SGV->getName() + 465 "' - Global variables differ in const'ness"); 466 467 // Otherwise, just perform the link. 468 ValueMap.insert(std::make_pair(SGV, DGV)); 469 470 // Linkonce+Weak = Weak 471 if (DGV->hasLinkOnceLinkage() && SGV->hasWeakLinkage()) 472 DGV->setLinkage(SGV->getLinkage()); 473 474 } else if (DGV->hasWeakLinkage() || DGV->hasLinkOnceLinkage()) { 475 // At this point we know that SGV has LinkOnce, Appending, or External 476 // linkage. If SGV is Appending, this is an error. 477 if (SGV->hasAppendingLinkage()) 478 return Error(Err, "Linking globals named '" + SGV->getName() + 479 " ' with 'weak' and 'appending' linkage is not allowed!"); 480 481 if (SGV->isConstant() != DGV->isConstant()) 482 return Error(Err, "Global Variable Collision on '" + 483 SGV->getType()->getDescription() + " %" + SGV->getName() + 484 "' - Global variables differ in const'ness"); 485 486 if (!SGV->hasLinkOnceLinkage()) 487 DGV->setLinkage(SGV->getLinkage()); // Inherit linkage! 488 ValueMap.insert(std::make_pair(SGV, DGV)); 489 490 } else if (SGV->getLinkage() != DGV->getLinkage()) { 491 return Error(Err, "Global variables named '" + SGV->getName() + 492 "' have different linkage specifiers!"); 493 } else if (SGV->hasExternalLinkage()) { 494 // Allow linking two exactly identical external global variables... 495 if (SGV->isConstant() != DGV->isConstant()) 496 return Error(Err, "Global Variable Collision on '" + 497 SGV->getType()->getDescription() + " %" + SGV->getName() + 498 "' - Global variables differ in const'ness"); 499 500 if (SGV->getInitializer() != DGV->getInitializer()) 501 return Error(Err, "Global Variable Collision on '" + 502 SGV->getType()->getDescription() + " %" + SGV->getName() + 503 "' - External linkage globals have different initializers"); 504 505 ValueMap.insert(std::make_pair(SGV, DGV)); 506 } else if (SGV->hasAppendingLinkage()) { 507 // No linking is performed yet. Just insert a new copy of the global, and 508 // keep track of the fact that it is an appending variable in the 509 // AppendingVars map. The name is cleared out so that no linkage is 510 // performed. 511 GlobalVariable *NewDGV = 512 new GlobalVariable(SGV->getType()->getElementType(), 513 SGV->isConstant(), SGV->getLinkage(), /*init*/0, 514 "", Dest); 515 516 // Make sure to remember this mapping... 517 ValueMap.insert(std::make_pair(SGV, NewDGV)); 518 519 // Keep track that this is an appending variable... 520 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV)); 521 } else { 522 assert(0 && "Unknown linkage!"); 523 } 524 } 525 return false; 526} 527 528 529// LinkGlobalInits - Update the initializers in the Dest module now that all 530// globals that may be referenced are in Dest. 531// 532static bool LinkGlobalInits(Module *Dest, const Module *Src, 533 std::map<const Value*, Value*> &ValueMap, 534 std::string *Err) { 535 536 // Loop over all of the globals in the src module, mapping them over as we go 537 // 538 for (Module::const_giterator I = Src->gbegin(), E = Src->gend(); I != E; ++I){ 539 const GlobalVariable *SGV = I; 540 541 if (SGV->hasInitializer()) { // Only process initialized GV's 542 // Figure out what the initializer looks like in the dest module... 543 Constant *SInit = 544 cast<Constant>(RemapOperand(SGV->getInitializer(), ValueMap, 0)); 545 546 GlobalVariable *DGV = cast<GlobalVariable>(ValueMap[SGV]); 547 if (DGV->hasInitializer()) { 548 if (SGV->hasExternalLinkage()) { 549 if (DGV->getInitializer() != SInit) 550 return Error(Err, "Global Variable Collision on '" + 551 SGV->getType()->getDescription() +"':%"+SGV->getName()+ 552 " - Global variables have different initializers"); 553 } else if (DGV->hasLinkOnceLinkage() || DGV->hasWeakLinkage()) { 554 // Nothing is required, mapped values will take the new global 555 // automatically. 556 } else if (SGV->hasLinkOnceLinkage() || SGV->hasWeakLinkage()) { 557 // Nothing is required, mapped values will take the new global 558 // automatically. 559 } else if (DGV->hasAppendingLinkage()) { 560 assert(0 && "Appending linkage unimplemented!"); 561 } else { 562 assert(0 && "Unknown linkage!"); 563 } 564 } else { 565 // Copy the initializer over now... 566 DGV->setInitializer(SInit); 567 } 568 } 569 } 570 return false; 571} 572 573// LinkFunctionProtos - Link the functions together between the two modules, 574// without doing function bodies... this just adds external function prototypes 575// to the Dest function... 576// 577static bool LinkFunctionProtos(Module *Dest, const Module *Src, 578 std::map<const Value*, Value*> &ValueMap, 579 std::map<std::string, GlobalValue*> &GlobalsByName, 580 std::string *Err) { 581 SymbolTable *ST = (SymbolTable*)&Dest->getSymbolTable(); 582 583 // Loop over all of the functions in the src module, mapping them over as we 584 // go 585 // 586 for (Module::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) { 587 const Function *SF = I; // SrcFunction 588 Function *DF = 0; 589 if (SF->hasName() && !SF->hasInternalLinkage()) { 590 // Check to see if may have to link the function. 591 if (!(DF = Dest->getFunction(SF->getName(), SF->getFunctionType()))) { 592 std::map<std::string, GlobalValue*>::iterator EF = 593 GlobalsByName.find(SF->getName()); 594 if (EF != GlobalsByName.end()) 595 DF = dyn_cast<Function>(EF->second); 596 if (DF && RecursiveResolveTypes(SF->getType(), DF->getType(), ST, "")) 597 DF = 0; // FIXME: gross. 598 } 599 } 600 601 if (!DF || SF->hasInternalLinkage() || DF->hasInternalLinkage()) { 602 // Function does not already exist, simply insert an function signature 603 // identical to SF into the dest module... 604 Function *NewDF = new Function(SF->getFunctionType(), SF->getLinkage(), 605 SF->getName(), Dest); 606 607 // If the LLVM runtime renamed the function, but it is an externally 608 // visible symbol, DF must be an existing function with internal linkage. 609 // Rename it. 610 if (NewDF->getName() != SF->getName() && !NewDF->hasInternalLinkage()) 611 ForceRenaming(NewDF, SF->getName()); 612 613 // ... and remember this mapping... 614 ValueMap.insert(std::make_pair(SF, NewDF)); 615 } else if (SF->isExternal()) { 616 // If SF is external or if both SF & DF are external.. Just link the 617 // external functions, we aren't adding anything. 618 ValueMap.insert(std::make_pair(SF, DF)); 619 } else if (DF->isExternal()) { // If DF is external but SF is not... 620 // Link the external functions, update linkage qualifiers 621 ValueMap.insert(std::make_pair(SF, DF)); 622 DF->setLinkage(SF->getLinkage()); 623 624 } else if (SF->hasWeakLinkage() || SF->hasLinkOnceLinkage()) { 625 // At this point we know that DF has LinkOnce, Weak, or External linkage. 626 ValueMap.insert(std::make_pair(SF, DF)); 627 628 // Linkonce+Weak = Weak 629 if (DF->hasLinkOnceLinkage() && SF->hasWeakLinkage()) 630 DF->setLinkage(SF->getLinkage()); 631 632 } else if (DF->hasWeakLinkage() || DF->hasLinkOnceLinkage()) { 633 // At this point we know that SF has LinkOnce or External linkage. 634 ValueMap.insert(std::make_pair(SF, DF)); 635 if (!SF->hasLinkOnceLinkage()) // Don't inherit linkonce linkage 636 DF->setLinkage(SF->getLinkage()); 637 638 } else if (SF->getLinkage() != DF->getLinkage()) { 639 return Error(Err, "Functions named '" + SF->getName() + 640 "' have different linkage specifiers!"); 641 } else if (SF->hasExternalLinkage()) { 642 // The function is defined in both modules!! 643 return Error(Err, "Function '" + 644 SF->getFunctionType()->getDescription() + "':\"" + 645 SF->getName() + "\" - Function is already defined!"); 646 } else { 647 assert(0 && "Unknown linkage configuration found!"); 648 } 649 } 650 return false; 651} 652 653// LinkFunctionBody - Copy the source function over into the dest function and 654// fix up references to values. At this point we know that Dest is an external 655// function, and that Src is not. 656// 657static bool LinkFunctionBody(Function *Dest, const Function *Src, 658 std::map<const Value*, Value*> &GlobalMap, 659 std::string *Err) { 660 assert(Src && Dest && Dest->isExternal() && !Src->isExternal()); 661 std::map<const Value*, Value*> LocalMap; // Map for function local values 662 663 // Go through and convert function arguments over... 664 Function::aiterator DI = Dest->abegin(); 665 for (Function::const_aiterator I = Src->abegin(), E = Src->aend(); 666 I != E; ++I, ++DI) { 667 DI->setName(I->getName()); // Copy the name information over... 668 669 // Add a mapping to our local map 670 LocalMap.insert(std::make_pair(I, DI)); 671 } 672 673 // Loop over all of the basic blocks, copying the instructions over... 674 // 675 for (Function::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) { 676 // Create new basic block and add to mapping and the Dest function... 677 BasicBlock *DBB = new BasicBlock(I->getName(), Dest); 678 LocalMap.insert(std::make_pair(I, DBB)); 679 680 // Loop over all of the instructions in the src basic block, copying them 681 // over. Note that this is broken in a strict sense because the cloned 682 // instructions will still be referencing values in the Src module, not 683 // the remapped values. In our case, however, we will not get caught and 684 // so we can delay patching the values up until later... 685 // 686 for (BasicBlock::const_iterator II = I->begin(), IE = I->end(); 687 II != IE; ++II) { 688 Instruction *DI = II->clone(); 689 DI->setName(II->getName()); 690 DBB->getInstList().push_back(DI); 691 LocalMap.insert(std::make_pair(II, DI)); 692 } 693 } 694 695 // At this point, all of the instructions and values of the function are now 696 // copied over. The only problem is that they are still referencing values in 697 // the Source function as operands. Loop through all of the operands of the 698 // functions and patch them up to point to the local versions... 699 // 700 for (Function::iterator BB = Dest->begin(), BE = Dest->end(); BB != BE; ++BB) 701 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) 702 for (Instruction::op_iterator OI = I->op_begin(), OE = I->op_end(); 703 OI != OE; ++OI) 704 *OI = RemapOperand(*OI, LocalMap, &GlobalMap); 705 706 return false; 707} 708 709 710// LinkFunctionBodies - Link in the function bodies that are defined in the 711// source module into the DestModule. This consists basically of copying the 712// function over and fixing up references to values. 713// 714static bool LinkFunctionBodies(Module *Dest, const Module *Src, 715 std::map<const Value*, Value*> &ValueMap, 716 std::string *Err) { 717 718 // Loop over all of the functions in the src module, mapping them over as we 719 // go 720 // 721 for (Module::const_iterator SF = Src->begin(), E = Src->end(); SF != E; ++SF){ 722 if (!SF->isExternal()) { // No body if function is external 723 Function *DF = cast<Function>(ValueMap[SF]); // Destination function 724 725 // DF not external SF external? 726 if (DF->isExternal()) { 727 // Only provide the function body if there isn't one already. 728 if (LinkFunctionBody(DF, SF, ValueMap, Err)) 729 return true; 730 } 731 } 732 } 733 return false; 734} 735 736// LinkAppendingVars - If there were any appending global variables, link them 737// together now. Return true on error. 738// 739static bool LinkAppendingVars(Module *M, 740 std::multimap<std::string, GlobalVariable *> &AppendingVars, 741 std::string *ErrorMsg) { 742 if (AppendingVars.empty()) return false; // Nothing to do. 743 744 // Loop over the multimap of appending vars, processing any variables with the 745 // same name, forming a new appending global variable with both of the 746 // initializers merged together, then rewrite references to the old variables 747 // and delete them. 748 // 749 std::vector<Constant*> Inits; 750 while (AppendingVars.size() > 1) { 751 // Get the first two elements in the map... 752 std::multimap<std::string, 753 GlobalVariable*>::iterator Second = AppendingVars.begin(), First=Second++; 754 755 // If the first two elements are for different names, there is no pair... 756 // Otherwise there is a pair, so link them together... 757 if (First->first == Second->first) { 758 GlobalVariable *G1 = First->second, *G2 = Second->second; 759 const ArrayType *T1 = cast<ArrayType>(G1->getType()->getElementType()); 760 const ArrayType *T2 = cast<ArrayType>(G2->getType()->getElementType()); 761 762 // Check to see that they two arrays agree on type... 763 if (T1->getElementType() != T2->getElementType()) 764 return Error(ErrorMsg, 765 "Appending variables with different element types need to be linked!"); 766 if (G1->isConstant() != G2->isConstant()) 767 return Error(ErrorMsg, 768 "Appending variables linked with different const'ness!"); 769 770 unsigned NewSize = T1->getNumElements() + T2->getNumElements(); 771 ArrayType *NewType = ArrayType::get(T1->getElementType(), NewSize); 772 773 // Create the new global variable... 774 GlobalVariable *NG = 775 new GlobalVariable(NewType, G1->isConstant(), G1->getLinkage(), 776 /*init*/0, First->first, M); 777 778 // Merge the initializer... 779 Inits.reserve(NewSize); 780 if (ConstantArray *I = dyn_cast<ConstantArray>(G1->getInitializer())) { 781 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i) 782 Inits.push_back(I->getOperand(i)); 783 } else { 784 assert(isa<ConstantAggregateZero>(G1->getInitializer())); 785 Constant *CV = Constant::getNullValue(T1->getElementType()); 786 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i) 787 Inits.push_back(CV); 788 } 789 if (ConstantArray *I = dyn_cast<ConstantArray>(G2->getInitializer())) { 790 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i) 791 Inits.push_back(I->getOperand(i)); 792 } else { 793 assert(isa<ConstantAggregateZero>(G2->getInitializer())); 794 Constant *CV = Constant::getNullValue(T2->getElementType()); 795 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i) 796 Inits.push_back(CV); 797 } 798 NG->setInitializer(ConstantArray::get(NewType, Inits)); 799 Inits.clear(); 800 801 // Replace any uses of the two global variables with uses of the new 802 // global... 803 804 // FIXME: This should rewrite simple/straight-forward uses such as 805 // getelementptr instructions to not use the Cast! 806 G1->replaceAllUsesWith(ConstantExpr::getCast(NG, G1->getType())); 807 G2->replaceAllUsesWith(ConstantExpr::getCast(NG, G2->getType())); 808 809 // Remove the two globals from the module now... 810 M->getGlobalList().erase(G1); 811 M->getGlobalList().erase(G2); 812 813 // Put the new global into the AppendingVars map so that we can handle 814 // linking of more than two vars... 815 Second->second = NG; 816 } 817 AppendingVars.erase(First); 818 } 819 820 return false; 821} 822 823 824// LinkModules - This function links two modules together, with the resulting 825// left module modified to be the composite of the two input modules. If an 826// error occurs, true is returned and ErrorMsg (if not null) is set to indicate 827// the problem. Upon failure, the Dest module could be in a modified state, and 828// shouldn't be relied on to be consistent. 829// 830bool llvm::LinkModules(Module *Dest, const Module *Src, std::string *ErrorMsg) { 831 if (Dest->getEndianness() == Module::AnyEndianness) 832 Dest->setEndianness(Src->getEndianness()); 833 if (Dest->getPointerSize() == Module::AnyPointerSize) 834 Dest->setPointerSize(Src->getPointerSize()); 835 836 if (Src->getEndianness() != Module::AnyEndianness && 837 Dest->getEndianness() != Src->getEndianness()) 838 std::cerr << "WARNING: Linking two modules of different endianness!\n"; 839 if (Src->getPointerSize() != Module::AnyPointerSize && 840 Dest->getPointerSize() != Src->getPointerSize()) 841 std::cerr << "WARNING: Linking two modules of different pointer size!\n"; 842 843 // LinkTypes - Go through the symbol table of the Src module and see if any 844 // types are named in the src module that are not named in the Dst module. 845 // Make sure there are no type name conflicts. 846 // 847 if (LinkTypes(Dest, Src, ErrorMsg)) return true; 848 849 // ValueMap - Mapping of values from what they used to be in Src, to what they 850 // are now in Dest. 851 // 852 std::map<const Value*, Value*> ValueMap; 853 854 // AppendingVars - Keep track of global variables in the destination module 855 // with appending linkage. After the module is linked together, they are 856 // appended and the module is rewritten. 857 // 858 std::multimap<std::string, GlobalVariable *> AppendingVars; 859 860 // GlobalsByName - The LLVM SymbolTable class fights our best efforts at 861 // linking by separating globals by type. Until PR411 is fixed, we replicate 862 // it's functionality here. 863 std::map<std::string, GlobalValue*> GlobalsByName; 864 865 for (Module::giterator I = Dest->gbegin(), E = Dest->gend(); I != E; ++I) { 866 // Add all of the appending globals already in the Dest module to 867 // AppendingVars. 868 if (I->hasAppendingLinkage()) 869 AppendingVars.insert(std::make_pair(I->getName(), I)); 870 871 // Keep track of all globals by name. 872 if (!I->hasInternalLinkage() && I->hasName()) 873 GlobalsByName[I->getName()] = I; 874 } 875 876 // Keep track of all globals by name. 877 for (Module::iterator I = Dest->begin(), E = Dest->end(); I != E; ++I) 878 if (!I->hasInternalLinkage() && I->hasName()) 879 GlobalsByName[I->getName()] = I; 880 881 // Insert all of the globals in src into the Dest module... without linking 882 // initializers (which could refer to functions not yet mapped over). 883 // 884 if (LinkGlobals(Dest, Src, ValueMap, AppendingVars, GlobalsByName, ErrorMsg)) 885 return true; 886 887 // Link the functions together between the two modules, without doing function 888 // bodies... this just adds external function prototypes to the Dest 889 // function... We do this so that when we begin processing function bodies, 890 // all of the global values that may be referenced are available in our 891 // ValueMap. 892 // 893 if (LinkFunctionProtos(Dest, Src, ValueMap, GlobalsByName, ErrorMsg)) 894 return true; 895 896 // Update the initializers in the Dest module now that all globals that may 897 // be referenced are in Dest. 898 // 899 if (LinkGlobalInits(Dest, Src, ValueMap, ErrorMsg)) return true; 900 901 // Link in the function bodies that are defined in the source module into the 902 // DestModule. This consists basically of copying the function over and 903 // fixing up references to values. 904 // 905 if (LinkFunctionBodies(Dest, Src, ValueMap, ErrorMsg)) return true; 906 907 // If there were any appending global variables, link them together now. 908 // 909 if (LinkAppendingVars(Dest, AppendingVars, ErrorMsg)) return true; 910 911 return false; 912} 913 914// vim: sw=2 915