LinkModules.cpp revision 72cf7df6a364c213a94d01e1f0f8d918940c8416
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> 27#include <sstream> 28using namespace llvm; 29 30// Error - Simple wrapper function to conditionally assign to E and return true. 31// This just makes error return conditions a little bit simpler... 32// 33static inline bool Error(std::string *E, const std::string &Message) { 34 if (E) *E = Message; 35 return true; 36} 37 38static std::string ToStr(const Type *Ty, const Module *M) { 39 std::ostringstream OS; 40 WriteTypeSymbolic(OS, Ty, M); 41 return OS.str(); 42} 43 44// 45// Function: ResolveTypes() 46// 47// Description: 48// Attempt to link the two specified types together. 49// 50// Inputs: 51// DestTy - The type to which we wish to resolve. 52// SrcTy - The original type which we want to resolve. 53// Name - The name of the type. 54// 55// Outputs: 56// DestST - The symbol table in which the new type should be placed. 57// 58// Return value: 59// true - There is an error and the types cannot yet be linked. 60// false - No errors. 61// 62static bool ResolveTypes(const Type *DestTy, const Type *SrcTy, 63 SymbolTable *DestST, const std::string &Name) { 64 if (DestTy == SrcTy) return false; // If already equal, noop 65 66 // Does the type already exist in the module? 67 if (DestTy && !isa<OpaqueType>(DestTy)) { // Yup, the type already exists... 68 if (const OpaqueType *OT = dyn_cast<OpaqueType>(SrcTy)) { 69 const_cast<OpaqueType*>(OT)->refineAbstractTypeTo(DestTy); 70 } else { 71 return true; // Cannot link types... neither is opaque and not-equal 72 } 73 } else { // Type not in dest module. Add it now. 74 if (DestTy) // Type _is_ in module, just opaque... 75 const_cast<OpaqueType*>(cast<OpaqueType>(DestTy)) 76 ->refineAbstractTypeTo(SrcTy); 77 else if (!Name.empty()) 78 DestST->insert(Name, const_cast<Type*>(SrcTy)); 79 } 80 return false; 81} 82 83static const FunctionType *getFT(const PATypeHolder &TH) { 84 return cast<FunctionType>(TH.get()); 85} 86static const StructType *getST(const PATypeHolder &TH) { 87 return cast<StructType>(TH.get()); 88} 89 90// RecursiveResolveTypes - This is just like ResolveTypes, except that it 91// recurses down into derived types, merging the used types if the parent types 92// are compatible. 93// 94static bool RecursiveResolveTypesI(const PATypeHolder &DestTy, 95 const PATypeHolder &SrcTy, 96 SymbolTable *DestST, const std::string &Name, 97 std::vector<std::pair<PATypeHolder, PATypeHolder> > &Pointers) { 98 const Type *SrcTyT = SrcTy.get(); 99 const Type *DestTyT = DestTy.get(); 100 if (DestTyT == SrcTyT) return false; // If already equal, noop 101 102 // If we found our opaque type, resolve it now! 103 if (isa<OpaqueType>(DestTyT) || isa<OpaqueType>(SrcTyT)) 104 return ResolveTypes(DestTyT, SrcTyT, DestST, Name); 105 106 // Two types cannot be resolved together if they are of different primitive 107 // type. For example, we cannot resolve an int to a float. 108 if (DestTyT->getTypeID() != SrcTyT->getTypeID()) return true; 109 110 // Otherwise, resolve the used type used by this derived type... 111 switch (DestTyT->getTypeID()) { 112 case Type::FunctionTyID: { 113 if (cast<FunctionType>(DestTyT)->isVarArg() != 114 cast<FunctionType>(SrcTyT)->isVarArg() || 115 cast<FunctionType>(DestTyT)->getNumContainedTypes() != 116 cast<FunctionType>(SrcTyT)->getNumContainedTypes()) 117 return true; 118 for (unsigned i = 0, e = getFT(DestTy)->getNumContainedTypes(); i != e; ++i) 119 if (RecursiveResolveTypesI(getFT(DestTy)->getContainedType(i), 120 getFT(SrcTy)->getContainedType(i), DestST, "", 121 Pointers)) 122 return true; 123 return false; 124 } 125 case Type::StructTyID: { 126 if (getST(DestTy)->getNumContainedTypes() != 127 getST(SrcTy)->getNumContainedTypes()) return 1; 128 for (unsigned i = 0, e = getST(DestTy)->getNumContainedTypes(); i != e; ++i) 129 if (RecursiveResolveTypesI(getST(DestTy)->getContainedType(i), 130 getST(SrcTy)->getContainedType(i), DestST, "", 131 Pointers)) 132 return true; 133 return false; 134 } 135 case Type::ArrayTyID: { 136 const ArrayType *DAT = cast<ArrayType>(DestTy.get()); 137 const ArrayType *SAT = cast<ArrayType>(SrcTy.get()); 138 if (DAT->getNumElements() != SAT->getNumElements()) return true; 139 return RecursiveResolveTypesI(DAT->getElementType(), SAT->getElementType(), 140 DestST, "", Pointers); 141 } 142 case Type::PointerTyID: { 143 // If this is a pointer type, check to see if we have already seen it. If 144 // so, we are in a recursive branch. Cut off the search now. We cannot use 145 // an associative container for this search, because the type pointers (keys 146 // in the container) change whenever types get resolved... 147 // 148 for (unsigned i = 0, e = Pointers.size(); i != e; ++i) 149 if (Pointers[i].first == DestTy) 150 return Pointers[i].second != SrcTy; 151 152 // Otherwise, add the current pointers to the vector to stop recursion on 153 // this pair. 154 Pointers.push_back(std::make_pair(DestTyT, SrcTyT)); 155 bool Result = 156 RecursiveResolveTypesI(cast<PointerType>(DestTy.get())->getElementType(), 157 cast<PointerType>(SrcTy.get())->getElementType(), 158 DestST, "", Pointers); 159 Pointers.pop_back(); 160 return Result; 161 } 162 default: assert(0 && "Unexpected type!"); return true; 163 } 164} 165 166static bool RecursiveResolveTypes(const PATypeHolder &DestTy, 167 const PATypeHolder &SrcTy, 168 SymbolTable *DestST, const std::string &Name){ 169 std::vector<std::pair<PATypeHolder, PATypeHolder> > PointerTypes; 170 return RecursiveResolveTypesI(DestTy, SrcTy, DestST, Name, PointerTypes); 171} 172 173 174// LinkTypes - Go through the symbol table of the Src module and see if any 175// types are named in the src module that are not named in the Dst module. 176// Make sure there are no type name conflicts. 177// 178static bool LinkTypes(Module *Dest, const Module *Src, std::string *Err) { 179 SymbolTable *DestST = &Dest->getSymbolTable(); 180 const SymbolTable *SrcST = &Src->getSymbolTable(); 181 182 // Look for a type plane for Type's... 183 SymbolTable::type_const_iterator TI = SrcST->type_begin(); 184 SymbolTable::type_const_iterator TE = SrcST->type_end(); 185 if (TI == TE) return false; // No named types, do nothing. 186 187 // Some types cannot be resolved immediately because they depend on other 188 // types being resolved to each other first. This contains a list of types we 189 // are waiting to recheck. 190 std::vector<std::string> DelayedTypesToResolve; 191 192 for ( ; TI != TE; ++TI ) { 193 const std::string &Name = TI->first; 194 const Type *RHS = TI->second; 195 196 // Check to see if this type name is already in the dest module... 197 Type *Entry = DestST->lookupType(Name); 198 199 if (ResolveTypes(Entry, RHS, DestST, Name)) { 200 // They look different, save the types 'till later to resolve. 201 DelayedTypesToResolve.push_back(Name); 202 } 203 } 204 205 // Iteratively resolve types while we can... 206 while (!DelayedTypesToResolve.empty()) { 207 // Loop over all of the types, attempting to resolve them if possible... 208 unsigned OldSize = DelayedTypesToResolve.size(); 209 210 // Try direct resolution by name... 211 for (unsigned i = 0; i != DelayedTypesToResolve.size(); ++i) { 212 const std::string &Name = DelayedTypesToResolve[i]; 213 Type *T1 = SrcST->lookupType(Name); 214 Type *T2 = DestST->lookupType(Name); 215 if (!ResolveTypes(T2, T1, DestST, Name)) { 216 // We are making progress! 217 DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i); 218 --i; 219 } 220 } 221 222 // Did we not eliminate any types? 223 if (DelayedTypesToResolve.size() == OldSize) { 224 // Attempt to resolve subelements of types. This allows us to merge these 225 // two types: { int* } and { opaque* } 226 for (unsigned i = 0, e = DelayedTypesToResolve.size(); i != e; ++i) { 227 const std::string &Name = DelayedTypesToResolve[i]; 228 PATypeHolder T1(SrcST->lookupType(Name)); 229 PATypeHolder T2(DestST->lookupType(Name)); 230 231 if (!RecursiveResolveTypes(T2, T1, DestST, Name)) { 232 // We are making progress! 233 DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i); 234 235 // Go back to the main loop, perhaps we can resolve directly by name 236 // now... 237 break; 238 } 239 } 240 241 // If we STILL cannot resolve the types, then there is something wrong. 242 // Report the warning and delete one of the names. 243 if (DelayedTypesToResolve.size() == OldSize) { 244 const std::string &Name = DelayedTypesToResolve.back(); 245 246 const Type *T1 = SrcST->lookupType(Name); 247 const Type *T2 = DestST->lookupType(Name); 248 std::cerr << "WARNING: Type conflict between types named '" << Name 249 << "'.\n Src='"; 250 WriteTypeSymbolic(std::cerr, T1, Src); 251 std::cerr << "'.\n Dest='"; 252 WriteTypeSymbolic(std::cerr, T2, Dest); 253 std::cerr << "'\n"; 254 255 // Remove the symbol name from the destination. 256 DelayedTypesToResolve.pop_back(); 257 } 258 } 259 } 260 261 262 return false; 263} 264 265static void PrintMap(const std::map<const Value*, Value*> &M) { 266 for (std::map<const Value*, Value*>::const_iterator I = M.begin(), E =M.end(); 267 I != E; ++I) { 268 std::cerr << " Fr: " << (void*)I->first << " "; 269 I->first->dump(); 270 std::cerr << " To: " << (void*)I->second << " "; 271 I->second->dump(); 272 std::cerr << "\n"; 273 } 274} 275 276 277// RemapOperand - Use LocalMap and GlobalMap to convert references from one 278// module to another. This is somewhat sophisticated in that it can 279// automatically handle constant references correctly as well... 280// 281static Value *RemapOperand(const Value *In, 282 std::map<const Value*, Value*> &LocalMap, 283 std::map<const Value*, Value*> *GlobalMap) { 284 std::map<const Value*,Value*>::const_iterator I = LocalMap.find(In); 285 if (I != LocalMap.end()) return I->second; 286 287 if (GlobalMap) { 288 I = GlobalMap->find(In); 289 if (I != GlobalMap->end()) return I->second; 290 } 291 292 // Check to see if it's a constant that we are interesting in transforming... 293 if (const Constant *CPV = dyn_cast<Constant>(In)) { 294 if ((!isa<DerivedType>(CPV->getType()) && !isa<ConstantExpr>(CPV)) || 295 isa<ConstantAggregateZero>(CPV)) 296 return const_cast<Constant*>(CPV); // Simple constants stay identical... 297 298 Constant *Result = 0; 299 300 if (const ConstantArray *CPA = dyn_cast<ConstantArray>(CPV)) { 301 std::vector<Constant*> Operands(CPA->getNumOperands()); 302 for (unsigned i = 0, e = CPA->getNumOperands(); i != e; ++i) 303 Operands[i] = 304 cast<Constant>(RemapOperand(CPA->getOperand(i), LocalMap, GlobalMap)); 305 Result = ConstantArray::get(cast<ArrayType>(CPA->getType()), Operands); 306 } else if (const ConstantStruct *CPS = dyn_cast<ConstantStruct>(CPV)) { 307 std::vector<Constant*> Operands(CPS->getNumOperands()); 308 for (unsigned i = 0, e = CPS->getNumOperands(); i != e; ++i) 309 Operands[i] = 310 cast<Constant>(RemapOperand(CPS->getOperand(i), LocalMap, GlobalMap)); 311 Result = ConstantStruct::get(cast<StructType>(CPS->getType()), Operands); 312 } else if (isa<ConstantPointerNull>(CPV)) { 313 Result = const_cast<Constant*>(CPV); 314 } else if (isa<GlobalValue>(CPV)) { 315 Result = cast<Constant>(RemapOperand(CPV, LocalMap, GlobalMap)); 316 } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CPV)) { 317 if (CE->getOpcode() == Instruction::GetElementPtr) { 318 Value *Ptr = RemapOperand(CE->getOperand(0), LocalMap, GlobalMap); 319 std::vector<Constant*> Indices; 320 Indices.reserve(CE->getNumOperands()-1); 321 for (unsigned i = 1, e = CE->getNumOperands(); i != e; ++i) 322 Indices.push_back(cast<Constant>(RemapOperand(CE->getOperand(i), 323 LocalMap, GlobalMap))); 324 325 Result = ConstantExpr::getGetElementPtr(cast<Constant>(Ptr), Indices); 326 } else if (CE->getNumOperands() == 1) { 327 // Cast instruction 328 assert(CE->getOpcode() == Instruction::Cast); 329 Value *V = RemapOperand(CE->getOperand(0), LocalMap, GlobalMap); 330 Result = ConstantExpr::getCast(cast<Constant>(V), CE->getType()); 331 } else if (CE->getNumOperands() == 3) { 332 // Select instruction 333 assert(CE->getOpcode() == Instruction::Select); 334 Value *V1 = RemapOperand(CE->getOperand(0), LocalMap, GlobalMap); 335 Value *V2 = RemapOperand(CE->getOperand(1), LocalMap, GlobalMap); 336 Value *V3 = RemapOperand(CE->getOperand(2), LocalMap, GlobalMap); 337 Result = ConstantExpr::getSelect(cast<Constant>(V1), cast<Constant>(V2), 338 cast<Constant>(V3)); 339 } else if (CE->getNumOperands() == 2) { 340 // Binary operator... 341 Value *V1 = RemapOperand(CE->getOperand(0), LocalMap, GlobalMap); 342 Value *V2 = RemapOperand(CE->getOperand(1), LocalMap, GlobalMap); 343 344 Result = ConstantExpr::get(CE->getOpcode(), cast<Constant>(V1), 345 cast<Constant>(V2)); 346 } else { 347 assert(0 && "Unknown constant expr type!"); 348 } 349 350 } else { 351 assert(0 && "Unknown type of derived type constant value!"); 352 } 353 354 // Cache the mapping in our local map structure... 355 if (GlobalMap) 356 GlobalMap->insert(std::make_pair(In, Result)); 357 else 358 LocalMap.insert(std::make_pair(In, Result)); 359 return Result; 360 } 361 362 std::cerr << "XXX LocalMap: \n"; 363 PrintMap(LocalMap); 364 365 if (GlobalMap) { 366 std::cerr << "XXX GlobalMap: \n"; 367 PrintMap(*GlobalMap); 368 } 369 370 std::cerr << "Couldn't remap value: " << (void*)In << " " << *In << "\n"; 371 assert(0 && "Couldn't remap value!"); 372 return 0; 373} 374 375/// ForceRenaming - The LLVM SymbolTable class autorenames globals that conflict 376/// in the symbol table. This is good for all clients except for us. Go 377/// through the trouble to force this back. 378static void ForceRenaming(GlobalValue *GV, const std::string &Name) { 379 assert(GV->getName() != Name && "Can't force rename to self"); 380 SymbolTable &ST = GV->getParent()->getSymbolTable(); 381 382 // If there is a conflict, rename the conflict. 383 Value *ConflictVal = ST.lookup(GV->getType(), Name); 384 assert(ConflictVal&&"Why do we have to force rename if there is no conflic?"); 385 GlobalValue *ConflictGV = cast<GlobalValue>(ConflictVal); 386 assert(ConflictGV->hasInternalLinkage() && 387 "Not conflicting with a static global, should link instead!"); 388 389 ConflictGV->setName(""); // Eliminate the conflict 390 GV->setName(Name); // Force the name back 391 ConflictGV->setName(Name); // This will cause ConflictGV to get renamed 392 assert(GV->getName() == Name && ConflictGV->getName() != Name && 393 "ForceRenaming didn't work"); 394} 395 396 397// LinkGlobals - Loop through the global variables in the src module and merge 398// them into the dest module. 399// 400static bool LinkGlobals(Module *Dest, const Module *Src, 401 std::map<const Value*, Value*> &ValueMap, 402 std::multimap<std::string, GlobalVariable *> &AppendingVars, 403 std::map<std::string, GlobalValue*> &GlobalsByName, 404 std::string *Err) { 405 // We will need a module level symbol table if the src module has a module 406 // level symbol table... 407 SymbolTable *ST = (SymbolTable*)&Dest->getSymbolTable(); 408 409 // Loop over all of the globals in the src module, mapping them over as we go 410 // 411 for (Module::const_giterator I = Src->gbegin(), E = Src->gend(); I != E; ++I){ 412 const GlobalVariable *SGV = I; 413 GlobalVariable *DGV = 0; 414 // Check to see if may have to link the global. 415 if (SGV->hasName() && !SGV->hasInternalLinkage()) 416 if (!(DGV = Dest->getGlobalVariable(SGV->getName(), 417 SGV->getType()->getElementType()))) { 418 std::map<std::string, GlobalValue*>::iterator EGV = 419 GlobalsByName.find(SGV->getName()); 420 if (EGV != GlobalsByName.end()) 421 DGV = dyn_cast<GlobalVariable>(EGV->second); 422 if (DGV && RecursiveResolveTypes(SGV->getType(), DGV->getType(), ST, "")) 423 DGV = 0; // FIXME: gross. 424 } 425 426 assert(SGV->hasInitializer() || SGV->hasExternalLinkage() && 427 "Global must either be external or have an initializer!"); 428 429 bool SGExtern = SGV->isExternal(); 430 bool DGExtern = DGV ? DGV->isExternal() : false; 431 432 if (!DGV || DGV->hasInternalLinkage() || SGV->hasInternalLinkage()) { 433 // No linking to be performed, simply create an identical version of the 434 // symbol over in the dest module... the initializer will be filled in 435 // later by LinkGlobalInits... 436 // 437 GlobalVariable *NewDGV = 438 new GlobalVariable(SGV->getType()->getElementType(), 439 SGV->isConstant(), SGV->getLinkage(), /*init*/0, 440 SGV->getName(), Dest); 441 442 // If the LLVM runtime renamed the global, but it is an externally visible 443 // symbol, DGV must be an existing global with internal linkage. Rename 444 // it. 445 if (NewDGV->getName() != SGV->getName() && !NewDGV->hasInternalLinkage()) 446 ForceRenaming(NewDGV, SGV->getName()); 447 448 // Make sure to remember this mapping... 449 ValueMap.insert(std::make_pair(SGV, NewDGV)); 450 if (SGV->hasAppendingLinkage()) 451 // Keep track that this is an appending variable... 452 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV)); 453 454 } else if (SGV->isExternal()) { 455 // If SGV is external or if both SGV & DGV are external.. Just link the 456 // external globals, we aren't adding anything. 457 ValueMap.insert(std::make_pair(SGV, DGV)); 458 459 } else if (DGV->isExternal()) { // If DGV is external but SGV is not... 460 ValueMap.insert(std::make_pair(SGV, DGV)); 461 DGV->setLinkage(SGV->getLinkage()); // Inherit linkage! 462 } else if (SGV->hasWeakLinkage() || SGV->hasLinkOnceLinkage()) { 463 // At this point we know that DGV has LinkOnce, Appending, Weak, or 464 // External linkage. If DGV is Appending, this is an error. 465 if (DGV->hasAppendingLinkage()) 466 return Error(Err, "Linking globals named '" + SGV->getName() + 467 " ' with 'weak' and 'appending' linkage is not allowed!"); 468 469 if (SGV->isConstant() != DGV->isConstant()) 470 return Error(Err, "Global Variable Collision on '" + 471 ToStr(SGV->getType(), Src) + " %" + SGV->getName() + 472 "' - Global variables differ in const'ness"); 473 474 // Otherwise, just perform the link. 475 ValueMap.insert(std::make_pair(SGV, DGV)); 476 477 // Linkonce+Weak = Weak 478 if (DGV->hasLinkOnceLinkage() && SGV->hasWeakLinkage()) 479 DGV->setLinkage(SGV->getLinkage()); 480 481 } else if (DGV->hasWeakLinkage() || DGV->hasLinkOnceLinkage()) { 482 // At this point we know that SGV has LinkOnce, Appending, or External 483 // linkage. If SGV is Appending, this is an error. 484 if (SGV->hasAppendingLinkage()) 485 return Error(Err, "Linking globals named '" + SGV->getName() + 486 " ' with 'weak' and 'appending' linkage is not allowed!"); 487 488 if (SGV->isConstant() != DGV->isConstant()) 489 return Error(Err, "Global Variable Collision on '" + 490 ToStr(SGV->getType(), Src) + " %" + SGV->getName() + 491 "' - Global variables differ in const'ness"); 492 493 if (!SGV->hasLinkOnceLinkage()) 494 DGV->setLinkage(SGV->getLinkage()); // Inherit linkage! 495 ValueMap.insert(std::make_pair(SGV, DGV)); 496 497 } else if (SGV->getLinkage() != DGV->getLinkage()) { 498 return Error(Err, "Global variables named '" + SGV->getName() + 499 "' have different linkage specifiers!"); 500 } else if (SGV->hasExternalLinkage()) { 501 // Allow linking two exactly identical external global variables... 502 if (SGV->isConstant() != DGV->isConstant()) 503 return Error(Err, "Global Variable Collision on '" + 504 ToStr(SGV->getType(), Src) + " %" + SGV->getName() + 505 "' - Global variables differ in const'ness"); 506 507 if (SGV->getInitializer() != DGV->getInitializer()) 508 return Error(Err, "Global Variable Collision on '" + 509 ToStr(SGV->getType(), Src) + " %" + SGV->getName() + 510 "' - External linkage globals have different initializers"); 511 512 ValueMap.insert(std::make_pair(SGV, DGV)); 513 } else if (SGV->hasAppendingLinkage()) { 514 // No linking is performed yet. Just insert a new copy of the global, and 515 // keep track of the fact that it is an appending variable in the 516 // AppendingVars map. The name is cleared out so that no linkage is 517 // performed. 518 GlobalVariable *NewDGV = 519 new GlobalVariable(SGV->getType()->getElementType(), 520 SGV->isConstant(), SGV->getLinkage(), /*init*/0, 521 "", Dest); 522 523 // Make sure to remember this mapping... 524 ValueMap.insert(std::make_pair(SGV, NewDGV)); 525 526 // Keep track that this is an appending variable... 527 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV)); 528 } else { 529 assert(0 && "Unknown linkage!"); 530 } 531 } 532 return false; 533} 534 535 536// LinkGlobalInits - Update the initializers in the Dest module now that all 537// globals that may be referenced are in Dest. 538// 539static bool LinkGlobalInits(Module *Dest, const Module *Src, 540 std::map<const Value*, Value*> &ValueMap, 541 std::string *Err) { 542 543 // Loop over all of the globals in the src module, mapping them over as we go 544 // 545 for (Module::const_giterator I = Src->gbegin(), E = Src->gend(); I != E; ++I){ 546 const GlobalVariable *SGV = I; 547 548 if (SGV->hasInitializer()) { // Only process initialized GV's 549 // Figure out what the initializer looks like in the dest module... 550 Constant *SInit = 551 cast<Constant>(RemapOperand(SGV->getInitializer(), ValueMap, 0)); 552 553 GlobalVariable *DGV = cast<GlobalVariable>(ValueMap[SGV]); 554 if (DGV->hasInitializer()) { 555 if (SGV->hasExternalLinkage()) { 556 if (DGV->getInitializer() != SInit) 557 return Error(Err, "Global Variable Collision on '" + 558 ToStr(SGV->getType(), Src) +"':%"+SGV->getName()+ 559 " - Global variables have different initializers"); 560 } else if (DGV->hasLinkOnceLinkage() || DGV->hasWeakLinkage()) { 561 // Nothing is required, mapped values will take the new global 562 // automatically. 563 } else if (SGV->hasLinkOnceLinkage() || SGV->hasWeakLinkage()) { 564 // Nothing is required, mapped values will take the new global 565 // automatically. 566 } else if (DGV->hasAppendingLinkage()) { 567 assert(0 && "Appending linkage unimplemented!"); 568 } else { 569 assert(0 && "Unknown linkage!"); 570 } 571 } else { 572 // Copy the initializer over now... 573 DGV->setInitializer(SInit); 574 } 575 } 576 } 577 return false; 578} 579 580// LinkFunctionProtos - Link the functions together between the two modules, 581// without doing function bodies... this just adds external function prototypes 582// to the Dest function... 583// 584static bool LinkFunctionProtos(Module *Dest, const Module *Src, 585 std::map<const Value*, Value*> &ValueMap, 586 std::map<std::string, GlobalValue*> &GlobalsByName, 587 std::string *Err) { 588 SymbolTable *ST = (SymbolTable*)&Dest->getSymbolTable(); 589 590 // Loop over all of the functions in the src module, mapping them over as we 591 // go 592 // 593 for (Module::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) { 594 const Function *SF = I; // SrcFunction 595 Function *DF = 0; 596 if (SF->hasName() && !SF->hasInternalLinkage()) { 597 // Check to see if may have to link the function. 598 if (!(DF = Dest->getFunction(SF->getName(), SF->getFunctionType()))) { 599 std::map<std::string, GlobalValue*>::iterator EF = 600 GlobalsByName.find(SF->getName()); 601 if (EF != GlobalsByName.end()) 602 DF = dyn_cast<Function>(EF->second); 603 if (DF && RecursiveResolveTypes(SF->getType(), DF->getType(), ST, "")) 604 DF = 0; // FIXME: gross. 605 } 606 } 607 608 if (!DF || SF->hasInternalLinkage() || DF->hasInternalLinkage()) { 609 // Function does not already exist, simply insert an function signature 610 // identical to SF into the dest module... 611 Function *NewDF = new Function(SF->getFunctionType(), SF->getLinkage(), 612 SF->getName(), Dest); 613 614 // If the LLVM runtime renamed the function, but it is an externally 615 // visible symbol, DF must be an existing function with internal linkage. 616 // Rename it. 617 if (NewDF->getName() != SF->getName() && !NewDF->hasInternalLinkage()) 618 ForceRenaming(NewDF, SF->getName()); 619 620 // ... and remember this mapping... 621 ValueMap.insert(std::make_pair(SF, NewDF)); 622 } else if (SF->isExternal()) { 623 // If SF is external or if both SF & DF are external.. Just link the 624 // external functions, we aren't adding anything. 625 ValueMap.insert(std::make_pair(SF, DF)); 626 } else if (DF->isExternal()) { // If DF is external but SF is not... 627 // Link the external functions, update linkage qualifiers 628 ValueMap.insert(std::make_pair(SF, DF)); 629 DF->setLinkage(SF->getLinkage()); 630 631 } else if (SF->hasWeakLinkage() || SF->hasLinkOnceLinkage()) { 632 // At this point we know that DF has LinkOnce, Weak, or External linkage. 633 ValueMap.insert(std::make_pair(SF, DF)); 634 635 // Linkonce+Weak = Weak 636 if (DF->hasLinkOnceLinkage() && SF->hasWeakLinkage()) 637 DF->setLinkage(SF->getLinkage()); 638 639 } else if (DF->hasWeakLinkage() || DF->hasLinkOnceLinkage()) { 640 // At this point we know that SF has LinkOnce or External linkage. 641 ValueMap.insert(std::make_pair(SF, DF)); 642 if (!SF->hasLinkOnceLinkage()) // Don't inherit linkonce linkage 643 DF->setLinkage(SF->getLinkage()); 644 645 } else if (SF->getLinkage() != DF->getLinkage()) { 646 return Error(Err, "Functions named '" + SF->getName() + 647 "' have different linkage specifiers!"); 648 } else if (SF->hasExternalLinkage()) { 649 // The function is defined in both modules!! 650 return Error(Err, "Function '" + 651 ToStr(SF->getFunctionType(), Src) + "':\"" + 652 SF->getName() + "\" - Function is already defined!"); 653 } else { 654 assert(0 && "Unknown linkage configuration found!"); 655 } 656 } 657 return false; 658} 659 660// LinkFunctionBody - Copy the source function over into the dest function and 661// fix up references to values. At this point we know that Dest is an external 662// function, and that Src is not. 663// 664static bool LinkFunctionBody(Function *Dest, const Function *Src, 665 std::map<const Value*, Value*> &GlobalMap, 666 std::string *Err) { 667 assert(Src && Dest && Dest->isExternal() && !Src->isExternal()); 668 std::map<const Value*, Value*> LocalMap; // Map for function local values 669 670 // Go through and convert function arguments over... 671 Function::aiterator DI = Dest->abegin(); 672 for (Function::const_aiterator I = Src->abegin(), E = Src->aend(); 673 I != E; ++I, ++DI) { 674 DI->setName(I->getName()); // Copy the name information over... 675 676 // Add a mapping to our local map 677 LocalMap.insert(std::make_pair(I, DI)); 678 } 679 680 // Loop over all of the basic blocks, copying the instructions over... 681 // 682 for (Function::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) { 683 // Create new basic block and add to mapping and the Dest function... 684 BasicBlock *DBB = new BasicBlock(I->getName(), Dest); 685 LocalMap.insert(std::make_pair(I, DBB)); 686 687 // Loop over all of the instructions in the src basic block, copying them 688 // over. Note that this is broken in a strict sense because the cloned 689 // instructions will still be referencing values in the Src module, not 690 // the remapped values. In our case, however, we will not get caught and 691 // so we can delay patching the values up until later... 692 // 693 for (BasicBlock::const_iterator II = I->begin(), IE = I->end(); 694 II != IE; ++II) { 695 Instruction *DI = II->clone(); 696 DI->setName(II->getName()); 697 DBB->getInstList().push_back(DI); 698 LocalMap.insert(std::make_pair(II, DI)); 699 } 700 } 701 702 // At this point, all of the instructions and values of the function are now 703 // copied over. The only problem is that they are still referencing values in 704 // the Source function as operands. Loop through all of the operands of the 705 // functions and patch them up to point to the local versions... 706 // 707 for (Function::iterator BB = Dest->begin(), BE = Dest->end(); BB != BE; ++BB) 708 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) 709 for (Instruction::op_iterator OI = I->op_begin(), OE = I->op_end(); 710 OI != OE; ++OI) 711 *OI = RemapOperand(*OI, LocalMap, &GlobalMap); 712 713 return false; 714} 715 716 717// LinkFunctionBodies - Link in the function bodies that are defined in the 718// source module into the DestModule. This consists basically of copying the 719// function over and fixing up references to values. 720// 721static bool LinkFunctionBodies(Module *Dest, const Module *Src, 722 std::map<const Value*, Value*> &ValueMap, 723 std::string *Err) { 724 725 // Loop over all of the functions in the src module, mapping them over as we 726 // go 727 // 728 for (Module::const_iterator SF = Src->begin(), E = Src->end(); SF != E; ++SF){ 729 if (!SF->isExternal()) { // No body if function is external 730 Function *DF = cast<Function>(ValueMap[SF]); // Destination function 731 732 // DF not external SF external? 733 if (DF->isExternal()) { 734 // Only provide the function body if there isn't one already. 735 if (LinkFunctionBody(DF, SF, ValueMap, Err)) 736 return true; 737 } 738 } 739 } 740 return false; 741} 742 743// LinkAppendingVars - If there were any appending global variables, link them 744// together now. Return true on error. 745// 746static bool LinkAppendingVars(Module *M, 747 std::multimap<std::string, GlobalVariable *> &AppendingVars, 748 std::string *ErrorMsg) { 749 if (AppendingVars.empty()) return false; // Nothing to do. 750 751 // Loop over the multimap of appending vars, processing any variables with the 752 // same name, forming a new appending global variable with both of the 753 // initializers merged together, then rewrite references to the old variables 754 // and delete them. 755 // 756 std::vector<Constant*> Inits; 757 while (AppendingVars.size() > 1) { 758 // Get the first two elements in the map... 759 std::multimap<std::string, 760 GlobalVariable*>::iterator Second = AppendingVars.begin(), First=Second++; 761 762 // If the first two elements are for different names, there is no pair... 763 // Otherwise there is a pair, so link them together... 764 if (First->first == Second->first) { 765 GlobalVariable *G1 = First->second, *G2 = Second->second; 766 const ArrayType *T1 = cast<ArrayType>(G1->getType()->getElementType()); 767 const ArrayType *T2 = cast<ArrayType>(G2->getType()->getElementType()); 768 769 // Check to see that they two arrays agree on type... 770 if (T1->getElementType() != T2->getElementType()) 771 return Error(ErrorMsg, 772 "Appending variables with different element types need to be linked!"); 773 if (G1->isConstant() != G2->isConstant()) 774 return Error(ErrorMsg, 775 "Appending variables linked with different const'ness!"); 776 777 unsigned NewSize = T1->getNumElements() + T2->getNumElements(); 778 ArrayType *NewType = ArrayType::get(T1->getElementType(), NewSize); 779 780 // Create the new global variable... 781 GlobalVariable *NG = 782 new GlobalVariable(NewType, G1->isConstant(), G1->getLinkage(), 783 /*init*/0, First->first, M); 784 785 // Merge the initializer... 786 Inits.reserve(NewSize); 787 if (ConstantArray *I = dyn_cast<ConstantArray>(G1->getInitializer())) { 788 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i) 789 Inits.push_back(I->getOperand(i)); 790 } else { 791 assert(isa<ConstantAggregateZero>(G1->getInitializer())); 792 Constant *CV = Constant::getNullValue(T1->getElementType()); 793 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i) 794 Inits.push_back(CV); 795 } 796 if (ConstantArray *I = dyn_cast<ConstantArray>(G2->getInitializer())) { 797 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i) 798 Inits.push_back(I->getOperand(i)); 799 } else { 800 assert(isa<ConstantAggregateZero>(G2->getInitializer())); 801 Constant *CV = Constant::getNullValue(T2->getElementType()); 802 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i) 803 Inits.push_back(CV); 804 } 805 NG->setInitializer(ConstantArray::get(NewType, Inits)); 806 Inits.clear(); 807 808 // Replace any uses of the two global variables with uses of the new 809 // global... 810 811 // FIXME: This should rewrite simple/straight-forward uses such as 812 // getelementptr instructions to not use the Cast! 813 G1->replaceAllUsesWith(ConstantExpr::getCast(NG, G1->getType())); 814 G2->replaceAllUsesWith(ConstantExpr::getCast(NG, G2->getType())); 815 816 // Remove the two globals from the module now... 817 M->getGlobalList().erase(G1); 818 M->getGlobalList().erase(G2); 819 820 // Put the new global into the AppendingVars map so that we can handle 821 // linking of more than two vars... 822 Second->second = NG; 823 } 824 AppendingVars.erase(First); 825 } 826 827 return false; 828} 829 830 831// LinkModules - This function links two modules together, with the resulting 832// left module modified to be the composite of the two input modules. If an 833// error occurs, true is returned and ErrorMsg (if not null) is set to indicate 834// the problem. Upon failure, the Dest module could be in a modified state, and 835// shouldn't be relied on to be consistent. 836// 837bool llvm::LinkModules(Module *Dest, const Module *Src, std::string *ErrorMsg) { 838 if (Dest->getEndianness() == Module::AnyEndianness) 839 Dest->setEndianness(Src->getEndianness()); 840 if (Dest->getPointerSize() == Module::AnyPointerSize) 841 Dest->setPointerSize(Src->getPointerSize()); 842 843 if (Src->getEndianness() != Module::AnyEndianness && 844 Dest->getEndianness() != Src->getEndianness()) 845 std::cerr << "WARNING: Linking two modules of different endianness!\n"; 846 if (Src->getPointerSize() != Module::AnyPointerSize && 847 Dest->getPointerSize() != Src->getPointerSize()) 848 std::cerr << "WARNING: Linking two modules of different pointer size!\n"; 849 850 // LinkTypes - Go through the symbol table of the Src module and see if any 851 // types are named in the src module that are not named in the Dst module. 852 // Make sure there are no type name conflicts. 853 // 854 if (LinkTypes(Dest, Src, ErrorMsg)) return true; 855 856 // ValueMap - Mapping of values from what they used to be in Src, to what they 857 // are now in Dest. 858 // 859 std::map<const Value*, Value*> ValueMap; 860 861 // AppendingVars - Keep track of global variables in the destination module 862 // with appending linkage. After the module is linked together, they are 863 // appended and the module is rewritten. 864 // 865 std::multimap<std::string, GlobalVariable *> AppendingVars; 866 867 // GlobalsByName - The LLVM SymbolTable class fights our best efforts at 868 // linking by separating globals by type. Until PR411 is fixed, we replicate 869 // it's functionality here. 870 std::map<std::string, GlobalValue*> GlobalsByName; 871 872 for (Module::giterator I = Dest->gbegin(), E = Dest->gend(); I != E; ++I) { 873 // Add all of the appending globals already in the Dest module to 874 // AppendingVars. 875 if (I->hasAppendingLinkage()) 876 AppendingVars.insert(std::make_pair(I->getName(), I)); 877 878 // Keep track of all globals by name. 879 if (!I->hasInternalLinkage() && I->hasName()) 880 GlobalsByName[I->getName()] = I; 881 } 882 883 // Keep track of all globals by name. 884 for (Module::iterator I = Dest->begin(), E = Dest->end(); I != E; ++I) 885 if (!I->hasInternalLinkage() && I->hasName()) 886 GlobalsByName[I->getName()] = I; 887 888 // Insert all of the globals in src into the Dest module... without linking 889 // initializers (which could refer to functions not yet mapped over). 890 // 891 if (LinkGlobals(Dest, Src, ValueMap, AppendingVars, GlobalsByName, ErrorMsg)) 892 return true; 893 894 // Link the functions together between the two modules, without doing function 895 // bodies... this just adds external function prototypes to the Dest 896 // function... We do this so that when we begin processing function bodies, 897 // all of the global values that may be referenced are available in our 898 // ValueMap. 899 // 900 if (LinkFunctionProtos(Dest, Src, ValueMap, GlobalsByName, ErrorMsg)) 901 return true; 902 903 // Update the initializers in the Dest module now that all globals that may 904 // be referenced are in Dest. 905 // 906 if (LinkGlobalInits(Dest, Src, ValueMap, ErrorMsg)) return true; 907 908 // Link in the function bodies that are defined in the source module into the 909 // DestModule. This consists basically of copying the function over and 910 // fixing up references to values. 911 // 912 if (LinkFunctionBodies(Dest, Src, ValueMap, ErrorMsg)) return true; 913 914 // If there were any appending global variables, link them together now. 915 // 916 if (LinkAppendingVars(Dest, AppendingVars, ErrorMsg)) return true; 917 918 return false; 919} 920 921// vim: sw=2 922