LinkModules.cpp revision 26f238589f9bb372d24b6fb2bc32edbf046fd9ee
1//===- lib/Linker/LinkModules.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/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/TypeSymbolTable.h" 25#include "llvm/Instructions.h" 26#include "llvm/Assembly/Writer.h" 27#include "llvm/Support/Streams.h" 28#include "llvm/System/Path.h" 29#include <sstream> 30using namespace llvm; 31 32// Error - Simple wrapper function to conditionally assign to E and return true. 33// This just makes error return conditions a little bit simpler... 34static inline bool Error(std::string *E, const std::string &Message) { 35 if (E) *E = Message; 36 return true; 37} 38 39// ToStr - Simple wrapper function to convert a type to a string. 40static std::string ToStr(const Type *Ty, const Module *M) { 41 std::ostringstream OS; 42 WriteTypeSymbolic(OS, Ty, M); 43 return OS.str(); 44} 45 46// 47// Function: ResolveTypes() 48// 49// Description: 50// Attempt to link the two specified types together. 51// 52// Inputs: 53// DestTy - The type to which we wish to resolve. 54// SrcTy - The original type which we want to resolve. 55// Name - The name of the type. 56// 57// Outputs: 58// DestST - The symbol table in which the new type should be placed. 59// 60// Return value: 61// true - There is an error and the types cannot yet be linked. 62// false - No errors. 63// 64static bool ResolveTypes(const Type *DestTy, const Type *SrcTy, 65 TypeSymbolTable *DestST, const std::string &Name) { 66 if (DestTy == SrcTy) return false; // If already equal, noop 67 68 // Does the type already exist in the module? 69 if (DestTy && !isa<OpaqueType>(DestTy)) { // Yup, the type already exists... 70 if (const OpaqueType *OT = dyn_cast<OpaqueType>(SrcTy)) { 71 const_cast<OpaqueType*>(OT)->refineAbstractTypeTo(DestTy); 72 } else { 73 return true; // Cannot link types... neither is opaque and not-equal 74 } 75 } else { // Type not in dest module. Add it now. 76 if (DestTy) // Type _is_ in module, just opaque... 77 const_cast<OpaqueType*>(cast<OpaqueType>(DestTy)) 78 ->refineAbstractTypeTo(SrcTy); 79 else if (!Name.empty()) 80 DestST->insert(Name, const_cast<Type*>(SrcTy)); 81 } 82 return false; 83} 84 85static const FunctionType *getFT(const PATypeHolder &TH) { 86 return cast<FunctionType>(TH.get()); 87} 88static const StructType *getST(const PATypeHolder &TH) { 89 return cast<StructType>(TH.get()); 90} 91 92// RecursiveResolveTypes - This is just like ResolveTypes, except that it 93// recurses down into derived types, merging the used types if the parent types 94// are compatible. 95static bool RecursiveResolveTypesI(const PATypeHolder &DestTy, 96 const PATypeHolder &SrcTy, 97 TypeSymbolTable *DestST, 98 const std::string &Name, 99 std::vector<std::pair<PATypeHolder, PATypeHolder> > &Pointers) { 100 const Type *SrcTyT = SrcTy.get(); 101 const Type *DestTyT = DestTy.get(); 102 if (DestTyT == SrcTyT) return false; // If already equal, noop 103 104 // If we found our opaque type, resolve it now! 105 if (isa<OpaqueType>(DestTyT) || isa<OpaqueType>(SrcTyT)) 106 return ResolveTypes(DestTyT, SrcTyT, DestST, Name); 107 108 // Two types cannot be resolved together if they are of different primitive 109 // type. For example, we cannot resolve an int to a float. 110 if (DestTyT->getTypeID() != SrcTyT->getTypeID()) return true; 111 112 // Otherwise, resolve the used type used by this derived type... 113 switch (DestTyT->getTypeID()) { 114 case Type::IntegerTyID: { 115 if (cast<IntegerType>(DestTyT)->getBitWidth() != 116 cast<IntegerType>(SrcTyT)->getBitWidth()) 117 return true; 118 return false; 119 } 120 case Type::FunctionTyID: { 121 if (cast<FunctionType>(DestTyT)->isVarArg() != 122 cast<FunctionType>(SrcTyT)->isVarArg() || 123 cast<FunctionType>(DestTyT)->getNumContainedTypes() != 124 cast<FunctionType>(SrcTyT)->getNumContainedTypes()) 125 return true; 126 for (unsigned i = 0, e = getFT(DestTy)->getNumContainedTypes(); i != e; ++i) 127 if (RecursiveResolveTypesI(getFT(DestTy)->getContainedType(i), 128 getFT(SrcTy)->getContainedType(i), DestST, "", 129 Pointers)) 130 return true; 131 return false; 132 } 133 case Type::StructTyID: { 134 if (getST(DestTy)->getNumContainedTypes() != 135 getST(SrcTy)->getNumContainedTypes()) return 1; 136 for (unsigned i = 0, e = getST(DestTy)->getNumContainedTypes(); i != e; ++i) 137 if (RecursiveResolveTypesI(getST(DestTy)->getContainedType(i), 138 getST(SrcTy)->getContainedType(i), DestST, "", 139 Pointers)) 140 return true; 141 return false; 142 } 143 case Type::ArrayTyID: { 144 const ArrayType *DAT = cast<ArrayType>(DestTy.get()); 145 const ArrayType *SAT = cast<ArrayType>(SrcTy.get()); 146 if (DAT->getNumElements() != SAT->getNumElements()) return true; 147 return RecursiveResolveTypesI(DAT->getElementType(), SAT->getElementType(), 148 DestST, "", Pointers); 149 } 150 case Type::PointerTyID: { 151 // If this is a pointer type, check to see if we have already seen it. If 152 // so, we are in a recursive branch. Cut off the search now. We cannot use 153 // an associative container for this search, because the type pointers (keys 154 // in the container) change whenever types get resolved... 155 for (unsigned i = 0, e = Pointers.size(); i != e; ++i) 156 if (Pointers[i].first == DestTy) 157 return Pointers[i].second != SrcTy; 158 159 // Otherwise, add the current pointers to the vector to stop recursion on 160 // this pair. 161 Pointers.push_back(std::make_pair(DestTyT, SrcTyT)); 162 bool Result = 163 RecursiveResolveTypesI(cast<PointerType>(DestTy.get())->getElementType(), 164 cast<PointerType>(SrcTy.get())->getElementType(), 165 DestST, "", Pointers); 166 Pointers.pop_back(); 167 return Result; 168 } 169 default: assert(0 && "Unexpected type!"); return true; 170 } 171} 172 173static bool RecursiveResolveTypes(const PATypeHolder &DestTy, 174 const PATypeHolder &SrcTy, 175 TypeSymbolTable *DestST, 176 const std::string &Name){ 177 std::vector<std::pair<PATypeHolder, PATypeHolder> > PointerTypes; 178 return RecursiveResolveTypesI(DestTy, SrcTy, DestST, Name, PointerTypes); 179} 180 181 182// LinkTypes - Go through the symbol table of the Src module and see if any 183// types are named in the src module that are not named in the Dst module. 184// Make sure there are no type name conflicts. 185static bool LinkTypes(Module *Dest, const Module *Src, std::string *Err) { 186 TypeSymbolTable *DestST = &Dest->getTypeSymbolTable(); 187 const TypeSymbolTable *SrcST = &Src->getTypeSymbolTable(); 188 189 // Look for a type plane for Type's... 190 TypeSymbolTable::const_iterator TI = SrcST->begin(); 191 TypeSymbolTable::const_iterator TE = SrcST->end(); 192 if (TI == TE) return false; // No named types, do nothing. 193 194 // Some types cannot be resolved immediately because they depend on other 195 // types being resolved to each other first. This contains a list of types we 196 // are waiting to recheck. 197 std::vector<std::string> DelayedTypesToResolve; 198 199 for ( ; TI != TE; ++TI ) { 200 const std::string &Name = TI->first; 201 const Type *RHS = TI->second; 202 203 // Check to see if this type name is already in the dest module... 204 Type *Entry = DestST->lookup(Name); 205 206 if (ResolveTypes(Entry, RHS, DestST, Name)) { 207 // They look different, save the types 'till later to resolve. 208 DelayedTypesToResolve.push_back(Name); 209 } 210 } 211 212 // Iteratively resolve types while we can... 213 while (!DelayedTypesToResolve.empty()) { 214 // Loop over all of the types, attempting to resolve them if possible... 215 unsigned OldSize = DelayedTypesToResolve.size(); 216 217 // Try direct resolution by name... 218 for (unsigned i = 0; i != DelayedTypesToResolve.size(); ++i) { 219 const std::string &Name = DelayedTypesToResolve[i]; 220 Type *T1 = SrcST->lookup(Name); 221 Type *T2 = DestST->lookup(Name); 222 if (!ResolveTypes(T2, T1, DestST, Name)) { 223 // We are making progress! 224 DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i); 225 --i; 226 } 227 } 228 229 // Did we not eliminate any types? 230 if (DelayedTypesToResolve.size() == OldSize) { 231 // Attempt to resolve subelements of types. This allows us to merge these 232 // two types: { int* } and { opaque* } 233 for (unsigned i = 0, e = DelayedTypesToResolve.size(); i != e; ++i) { 234 const std::string &Name = DelayedTypesToResolve[i]; 235 PATypeHolder T1(SrcST->lookup(Name)); 236 PATypeHolder T2(DestST->lookup(Name)); 237 238 if (!RecursiveResolveTypes(T2, T1, DestST, Name)) { 239 // We are making progress! 240 DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i); 241 242 // Go back to the main loop, perhaps we can resolve directly by name 243 // now... 244 break; 245 } 246 } 247 248 // If we STILL cannot resolve the types, then there is something wrong. 249 if (DelayedTypesToResolve.size() == OldSize) { 250 // Remove the symbol name from the destination. 251 DelayedTypesToResolve.pop_back(); 252 } 253 } 254 } 255 256 257 return false; 258} 259 260static void PrintMap(const std::map<const Value*, Value*> &M) { 261 for (std::map<const Value*, Value*>::const_iterator I = M.begin(), E =M.end(); 262 I != E; ++I) { 263 cerr << " Fr: " << (void*)I->first << " "; 264 I->first->dump(); 265 cerr << " To: " << (void*)I->second << " "; 266 I->second->dump(); 267 cerr << "\n"; 268 } 269} 270 271 272// RemapOperand - Use ValueMap to convert references from one module to another. 273// This is somewhat sophisticated in that it can automatically handle constant 274// references correctly as well. 275static Value *RemapOperand(const Value *In, 276 std::map<const Value*, Value*> &ValueMap) { 277 std::map<const Value*,Value*>::const_iterator I = ValueMap.find(In); 278 if (I != ValueMap.end()) return I->second; 279 280 // Check to see if it's a constant that we are interesting in transforming. 281 Value *Result = 0; 282 if (const Constant *CPV = dyn_cast<Constant>(In)) { 283 if ((!isa<DerivedType>(CPV->getType()) && !isa<ConstantExpr>(CPV)) || 284 isa<ConstantInt>(CPV) || isa<ConstantAggregateZero>(CPV)) 285 return const_cast<Constant*>(CPV); // Simple constants stay identical. 286 287 if (const ConstantArray *CPA = dyn_cast<ConstantArray>(CPV)) { 288 std::vector<Constant*> Operands(CPA->getNumOperands()); 289 for (unsigned i = 0, e = CPA->getNumOperands(); i != e; ++i) 290 Operands[i] =cast<Constant>(RemapOperand(CPA->getOperand(i), ValueMap)); 291 Result = ConstantArray::get(cast<ArrayType>(CPA->getType()), Operands); 292 } else if (const ConstantStruct *CPS = dyn_cast<ConstantStruct>(CPV)) { 293 std::vector<Constant*> Operands(CPS->getNumOperands()); 294 for (unsigned i = 0, e = CPS->getNumOperands(); i != e; ++i) 295 Operands[i] =cast<Constant>(RemapOperand(CPS->getOperand(i), ValueMap)); 296 Result = ConstantStruct::get(cast<StructType>(CPS->getType()), Operands); 297 } else if (isa<ConstantPointerNull>(CPV) || isa<UndefValue>(CPV)) { 298 Result = const_cast<Constant*>(CPV); 299 } else if (isa<GlobalValue>(CPV)) { 300 Result = cast<Constant>(RemapOperand(CPV, ValueMap)); 301 } else if (const ConstantPacked *CP = dyn_cast<ConstantPacked>(CPV)) { 302 std::vector<Constant*> Operands(CP->getNumOperands()); 303 for (unsigned i = 0, e = CP->getNumOperands(); i != e; ++i) 304 Operands[i] = cast<Constant>(RemapOperand(CP->getOperand(i), ValueMap)); 305 Result = ConstantPacked::get(Operands); 306 } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CPV)) { 307 std::vector<Constant*> Ops; 308 for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) 309 Ops.push_back(cast<Constant>(RemapOperand(CE->getOperand(i),ValueMap))); 310 Result = CE->getWithOperands(Ops); 311 } else { 312 assert(0 && "Unknown type of derived type constant value!"); 313 } 314 } else if (isa<InlineAsm>(In)) { 315 Result = const_cast<Value*>(In); 316 } 317 318 // Cache the mapping in our local map structure... 319 if (Result) { 320 ValueMap.insert(std::make_pair(In, Result)); 321 return Result; 322 } 323 324 325 cerr << "LinkModules ValueMap: \n"; 326 PrintMap(ValueMap); 327 328 cerr << "Couldn't remap value: " << (void*)In << " " << *In << "\n"; 329 assert(0 && "Couldn't remap value!"); 330 return 0; 331} 332 333/// ForceRenaming - The LLVM SymbolTable class autorenames globals that conflict 334/// in the symbol table. This is good for all clients except for us. Go 335/// through the trouble to force this back. 336static void ForceRenaming(GlobalValue *GV, const std::string &Name) { 337 assert(GV->getName() != Name && "Can't force rename to self"); 338 SymbolTable &ST = GV->getParent()->getValueSymbolTable(); 339 340 // If there is a conflict, rename the conflict. 341 Value *ConflictVal = ST.lookup(GV->getType(), Name); 342 assert(ConflictVal&&"Why do we have to force rename if there is no conflic?"); 343 GlobalValue *ConflictGV = cast<GlobalValue>(ConflictVal); 344 assert(ConflictGV->hasInternalLinkage() && 345 "Not conflicting with a static global, should link instead!"); 346 347 ConflictGV->setName(""); // Eliminate the conflict 348 GV->setName(Name); // Force the name back 349 ConflictGV->setName(Name); // This will cause ConflictGV to get renamed 350 assert(GV->getName() == Name && ConflictGV->getName() != Name && 351 "ForceRenaming didn't work"); 352} 353 354/// GetLinkageResult - This analyzes the two global values and determines what 355/// the result will look like in the destination module. In particular, it 356/// computes the resultant linkage type, computes whether the global in the 357/// source should be copied over to the destination (replacing the existing 358/// one), and computes whether this linkage is an error or not. 359static bool GetLinkageResult(GlobalValue *Dest, GlobalValue *Src, 360 GlobalValue::LinkageTypes <, bool &LinkFromSrc, 361 std::string *Err) { 362 assert((!Dest || !Src->hasInternalLinkage()) && 363 "If Src has internal linkage, Dest shouldn't be set!"); 364 if (!Dest) { 365 // Linking something to nothing. 366 LinkFromSrc = true; 367 LT = Src->getLinkage(); 368 } else if (Src->isExternal()) { 369 // If Src is external or if both Src & Drc are external.. Just link the 370 // external globals, we aren't adding anything. 371 if (Src->hasDLLImportLinkage()) { 372 // If one of GVs has DLLImport linkage, result should be dllimport'ed. 373 if (Dest->isExternal()) { 374 LinkFromSrc = true; 375 LT = Src->getLinkage(); 376 } 377 } else if (Dest->hasExternalWeakLinkage()) { 378 //If the Dest is weak, use the source linkage 379 LinkFromSrc = true; 380 LT = Src->getLinkage(); 381 } else { 382 LinkFromSrc = false; 383 LT = Dest->getLinkage(); 384 } 385 } else if (Dest->isExternal() && !Dest->hasDLLImportLinkage()) { 386 // If Dest is external but Src is not: 387 LinkFromSrc = true; 388 LT = Src->getLinkage(); 389 } else if (Src->hasAppendingLinkage() || Dest->hasAppendingLinkage()) { 390 if (Src->getLinkage() != Dest->getLinkage()) 391 return Error(Err, "Linking globals named '" + Src->getName() + 392 "': can only link appending global with another appending global!"); 393 LinkFromSrc = true; // Special cased. 394 LT = Src->getLinkage(); 395 } else if (Src->hasWeakLinkage() || Src->hasLinkOnceLinkage()) { 396 // At this point we know that Dest has LinkOnce, External*, Weak, DLL* linkage. 397 if ((Dest->hasLinkOnceLinkage() && Src->hasWeakLinkage()) || 398 Dest->hasExternalWeakLinkage()) { 399 LinkFromSrc = true; 400 LT = Src->getLinkage(); 401 } else { 402 LinkFromSrc = false; 403 LT = Dest->getLinkage(); 404 } 405 } else if (Dest->hasWeakLinkage() || Dest->hasLinkOnceLinkage()) { 406 // At this point we know that Src has External* or DLL* linkage. 407 if (Src->hasExternalWeakLinkage()) { 408 LinkFromSrc = false; 409 LT = Dest->getLinkage(); 410 } else { 411 LinkFromSrc = true; 412 LT = GlobalValue::ExternalLinkage; 413 } 414 } else { 415 assert((Dest->hasExternalLinkage() || 416 Dest->hasDLLImportLinkage() || 417 Dest->hasDLLExportLinkage() || 418 Dest->hasExternalWeakLinkage()) && 419 (Src->hasExternalLinkage() || 420 Src->hasDLLImportLinkage() || 421 Src->hasDLLExportLinkage() || 422 Src->hasExternalWeakLinkage()) && 423 "Unexpected linkage type!"); 424 return Error(Err, "Linking globals named '" + Src->getName() + 425 "': symbol multiply defined!"); 426 } 427 return false; 428} 429 430// LinkGlobals - Loop through the global variables in the src module and merge 431// them into the dest module. 432static bool LinkGlobals(Module *Dest, Module *Src, 433 std::map<const Value*, Value*> &ValueMap, 434 std::multimap<std::string, GlobalVariable *> &AppendingVars, 435 std::map<std::string, GlobalValue*> &GlobalsByName, 436 std::string *Err) { 437 // We will need a module level symbol table if the src module has a module 438 // level symbol table... 439 TypeSymbolTable *TST = &Dest->getTypeSymbolTable(); 440 441 // Loop over all of the globals in the src module, mapping them over as we go 442 for (Module::global_iterator I = Src->global_begin(), E = Src->global_end(); 443 I != E; ++I) { 444 GlobalVariable *SGV = I; 445 GlobalVariable *DGV = 0; 446 // Check to see if may have to link the global. 447 if (SGV->hasName() && !SGV->hasInternalLinkage()) 448 if (!(DGV = Dest->getGlobalVariable(SGV->getName(), 449 SGV->getType()->getElementType()))) { 450 std::map<std::string, GlobalValue*>::iterator EGV = 451 GlobalsByName.find(SGV->getName()); 452 if (EGV != GlobalsByName.end()) 453 DGV = dyn_cast<GlobalVariable>(EGV->second); 454 if (DGV) 455 // If types don't agree due to opaque types, try to resolve them. 456 RecursiveResolveTypes(SGV->getType(), DGV->getType(), TST, ""); 457 } 458 459 if (DGV && DGV->hasInternalLinkage()) 460 DGV = 0; 461 462 assert(SGV->hasInitializer() || SGV->hasExternalWeakLinkage() || 463 SGV->hasExternalLinkage() || SGV->hasDLLImportLinkage() && 464 "Global must either be external or have an initializer!"); 465 466 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; 467 bool LinkFromSrc = false; 468 if (GetLinkageResult(DGV, SGV, NewLinkage, LinkFromSrc, Err)) 469 return true; 470 471 if (!DGV) { 472 // No linking to be performed, simply create an identical version of the 473 // symbol over in the dest module... the initializer will be filled in 474 // later by LinkGlobalInits... 475 GlobalVariable *NewDGV = 476 new GlobalVariable(SGV->getType()->getElementType(), 477 SGV->isConstant(), SGV->getLinkage(), /*init*/0, 478 SGV->getName(), Dest); 479 // Propagate alignment info. 480 NewDGV->setAlignment(SGV->getAlignment()); 481 482 // If the LLVM runtime renamed the global, but it is an externally visible 483 // symbol, DGV must be an existing global with internal linkage. Rename 484 // it. 485 if (NewDGV->getName() != SGV->getName() && !NewDGV->hasInternalLinkage()) 486 ForceRenaming(NewDGV, SGV->getName()); 487 488 // Make sure to remember this mapping... 489 ValueMap.insert(std::make_pair(SGV, NewDGV)); 490 if (SGV->hasAppendingLinkage()) 491 // Keep track that this is an appending variable... 492 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV)); 493 } else if (DGV->hasAppendingLinkage()) { 494 // No linking is performed yet. Just insert a new copy of the global, and 495 // keep track of the fact that it is an appending variable in the 496 // AppendingVars map. The name is cleared out so that no linkage is 497 // performed. 498 GlobalVariable *NewDGV = 499 new GlobalVariable(SGV->getType()->getElementType(), 500 SGV->isConstant(), SGV->getLinkage(), /*init*/0, 501 "", Dest); 502 503 // Propagate alignment info. 504 NewDGV->setAlignment(std::max(DGV->getAlignment(), SGV->getAlignment())); 505 506 // Make sure to remember this mapping... 507 ValueMap.insert(std::make_pair(SGV, NewDGV)); 508 509 // Keep track that this is an appending variable... 510 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV)); 511 } else { 512 // Propagate alignment info. 513 DGV->setAlignment(std::max(DGV->getAlignment(), SGV->getAlignment())); 514 515 // Otherwise, perform the mapping as instructed by GetLinkageResult. If 516 // the types don't match, and if we are to link from the source, nuke DGV 517 // and create a new one of the appropriate type. 518 if (SGV->getType() != DGV->getType() && LinkFromSrc) { 519 GlobalVariable *NewDGV = 520 new GlobalVariable(SGV->getType()->getElementType(), 521 DGV->isConstant(), DGV->getLinkage()); 522 NewDGV->setAlignment(DGV->getAlignment()); 523 Dest->getGlobalList().insert(DGV, NewDGV); 524 DGV->replaceAllUsesWith( 525 ConstantExpr::getBitCast(NewDGV, DGV->getType())); 526 DGV->eraseFromParent(); 527 NewDGV->setName(SGV->getName()); 528 DGV = NewDGV; 529 } 530 531 DGV->setLinkage(NewLinkage); 532 533 if (LinkFromSrc) { 534 // Inherit const as appropriate 535 DGV->setConstant(SGV->isConstant()); 536 DGV->setInitializer(0); 537 } else { 538 if (SGV->isConstant() && !DGV->isConstant()) { 539 if (DGV->isExternal()) 540 DGV->setConstant(true); 541 } 542 SGV->setLinkage(GlobalValue::ExternalLinkage); 543 SGV->setInitializer(0); 544 } 545 546 ValueMap.insert( 547 std::make_pair(SGV, ConstantExpr::getBitCast(DGV, SGV->getType()))); 548 } 549 } 550 return false; 551} 552 553 554// LinkGlobalInits - Update the initializers in the Dest module now that all 555// globals that may be referenced are in Dest. 556static bool LinkGlobalInits(Module *Dest, const Module *Src, 557 std::map<const Value*, Value*> &ValueMap, 558 std::string *Err) { 559 560 // Loop over all of the globals in the src module, mapping them over as we go 561 for (Module::const_global_iterator I = Src->global_begin(), 562 E = Src->global_end(); I != E; ++I) { 563 const GlobalVariable *SGV = I; 564 565 if (SGV->hasInitializer()) { // Only process initialized GV's 566 // Figure out what the initializer looks like in the dest module... 567 Constant *SInit = 568 cast<Constant>(RemapOperand(SGV->getInitializer(), ValueMap)); 569 570 GlobalVariable *DGV = cast<GlobalVariable>(ValueMap[SGV]); 571 if (DGV->hasInitializer()) { 572 if (SGV->hasExternalLinkage()) { 573 if (DGV->getInitializer() != SInit) 574 return Error(Err, "Global Variable Collision on '" + 575 ToStr(SGV->getType(), Src) +"':%"+SGV->getName()+ 576 " - Global variables have different initializers"); 577 } else if (DGV->hasLinkOnceLinkage() || DGV->hasWeakLinkage()) { 578 // Nothing is required, mapped values will take the new global 579 // automatically. 580 } else if (SGV->hasLinkOnceLinkage() || SGV->hasWeakLinkage()) { 581 // Nothing is required, mapped values will take the new global 582 // automatically. 583 } else if (DGV->hasAppendingLinkage()) { 584 assert(0 && "Appending linkage unimplemented!"); 585 } else { 586 assert(0 && "Unknown linkage!"); 587 } 588 } else { 589 // Copy the initializer over now... 590 DGV->setInitializer(SInit); 591 } 592 } 593 } 594 return false; 595} 596 597// LinkFunctionProtos - Link the functions together between the two modules, 598// without doing function bodies... this just adds external function prototypes 599// to the Dest function... 600// 601static bool LinkFunctionProtos(Module *Dest, const Module *Src, 602 std::map<const Value*, Value*> &ValueMap, 603 std::map<std::string, 604 GlobalValue*> &GlobalsByName, 605 std::string *Err) { 606 TypeSymbolTable *TST = &Dest->getTypeSymbolTable(); 607 608 // Loop over all of the functions in the src module, mapping them over as we 609 // go 610 for (Module::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) { 611 const Function *SF = I; // SrcFunction 612 Function *DF = 0; 613 if (SF->hasName() && !SF->hasInternalLinkage()) { 614 // Check to see if may have to link the function. 615 if (!(DF = Dest->getFunction(SF->getName(), SF->getFunctionType()))) { 616 std::map<std::string, GlobalValue*>::iterator EF = 617 GlobalsByName.find(SF->getName()); 618 if (EF != GlobalsByName.end()) 619 DF = dyn_cast<Function>(EF->second); 620 if (DF && RecursiveResolveTypes(SF->getType(), DF->getType(), TST, "")) 621 DF = 0; // FIXME: gross. 622 } 623 } 624 625 if (!DF || SF->hasInternalLinkage() || DF->hasInternalLinkage()) { 626 // Function does not already exist, simply insert an function signature 627 // identical to SF into the dest module... 628 Function *NewDF = new Function(SF->getFunctionType(), SF->getLinkage(), 629 SF->getName(), Dest); 630 NewDF->setCallingConv(SF->getCallingConv()); 631 632 // If the LLVM runtime renamed the function, but it is an externally 633 // visible symbol, DF must be an existing function with internal linkage. 634 // Rename it. 635 if (NewDF->getName() != SF->getName() && !NewDF->hasInternalLinkage()) 636 ForceRenaming(NewDF, SF->getName()); 637 638 // ... and remember this mapping... 639 ValueMap.insert(std::make_pair(SF, NewDF)); 640 } else if (SF->isExternal()) { 641 // If SF is external or if both SF & DF are external.. Just link the 642 // external functions, we aren't adding anything. 643 if (SF->hasDLLImportLinkage()) { 644 if (DF->isExternal()) { 645 ValueMap.insert(std::make_pair(SF, DF)); 646 DF->setLinkage(SF->getLinkage()); 647 } 648 } else { 649 ValueMap.insert(std::make_pair(SF, DF)); 650 } 651 } else if (DF->isExternal() && !DF->hasDLLImportLinkage()) { 652 // If DF is external but SF is not... 653 // Link the external functions, update linkage qualifiers 654 ValueMap.insert(std::make_pair(SF, DF)); 655 DF->setLinkage(SF->getLinkage()); 656 } else if (SF->hasWeakLinkage() || SF->hasLinkOnceLinkage()) { 657 // At this point we know that DF has LinkOnce, Weak, or External* linkage. 658 ValueMap.insert(std::make_pair(SF, DF)); 659 660 // Linkonce+Weak = Weak 661 // *+External Weak = * 662 if ((DF->hasLinkOnceLinkage() && SF->hasWeakLinkage()) || 663 DF->hasExternalWeakLinkage()) 664 DF->setLinkage(SF->getLinkage()); 665 666 667 } else if (DF->hasWeakLinkage() || DF->hasLinkOnceLinkage()) { 668 // At this point we know that SF has LinkOnce or External* linkage. 669 ValueMap.insert(std::make_pair(SF, DF)); 670 if (!SF->hasLinkOnceLinkage() && !SF->hasExternalWeakLinkage()) 671 // Don't inherit linkonce & external weak linkage 672 DF->setLinkage(SF->getLinkage()); 673 } else if (SF->getLinkage() != DF->getLinkage()) { 674 return Error(Err, "Functions named '" + SF->getName() + 675 "' have different linkage specifiers!"); 676 } else if (SF->hasExternalLinkage()) { 677 // The function is defined in both modules!! 678 return Error(Err, "Function '" + 679 ToStr(SF->getFunctionType(), Src) + "':\"" + 680 SF->getName() + "\" - Function is already defined!"); 681 } else { 682 assert(0 && "Unknown linkage configuration found!"); 683 } 684 } 685 return false; 686} 687 688// LinkFunctionBody - Copy the source function over into the dest function and 689// fix up references to values. At this point we know that Dest is an external 690// function, and that Src is not. 691static bool LinkFunctionBody(Function *Dest, Function *Src, 692 std::map<const Value*, Value*> &GlobalMap, 693 std::string *Err) { 694 assert(Src && Dest && Dest->isExternal() && !Src->isExternal()); 695 696 // Go through and convert function arguments over, remembering the mapping. 697 Function::arg_iterator DI = Dest->arg_begin(); 698 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end(); 699 I != E; ++I, ++DI) { 700 DI->setName(I->getName()); // Copy the name information over... 701 702 // Add a mapping to our local map 703 GlobalMap.insert(std::make_pair(I, DI)); 704 } 705 706 // Splice the body of the source function into the dest function. 707 Dest->getBasicBlockList().splice(Dest->end(), Src->getBasicBlockList()); 708 709 // At this point, all of the instructions and values of the function are now 710 // copied over. The only problem is that they are still referencing values in 711 // the Source function as operands. Loop through all of the operands of the 712 // functions and patch them up to point to the local versions... 713 // 714 for (Function::iterator BB = Dest->begin(), BE = Dest->end(); BB != BE; ++BB) 715 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) 716 for (Instruction::op_iterator OI = I->op_begin(), OE = I->op_end(); 717 OI != OE; ++OI) 718 if (!isa<Instruction>(*OI) && !isa<BasicBlock>(*OI)) 719 *OI = RemapOperand(*OI, GlobalMap); 720 721 // There is no need to map the arguments anymore. 722 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end(); 723 I != E; ++I) 724 GlobalMap.erase(I); 725 726 return false; 727} 728 729 730// LinkFunctionBodies - Link in the function bodies that are defined in the 731// source module into the DestModule. This consists basically of copying the 732// function over and fixing up references to values. 733static bool LinkFunctionBodies(Module *Dest, Module *Src, 734 std::map<const Value*, Value*> &ValueMap, 735 std::string *Err) { 736 737 // Loop over all of the functions in the src module, mapping them over as we 738 // go 739 for (Module::iterator SF = Src->begin(), E = Src->end(); SF != E; ++SF) { 740 if (!SF->isExternal()) { // No body if function is external 741 Function *DF = cast<Function>(ValueMap[SF]); // Destination function 742 743 // DF not external SF external? 744 if (DF->isExternal()) { 745 // Only provide the function body if there isn't one already. 746 if (LinkFunctionBody(DF, SF, ValueMap, Err)) 747 return true; 748 } 749 } 750 } 751 return false; 752} 753 754// LinkAppendingVars - If there were any appending global variables, link them 755// together now. Return true on error. 756static bool LinkAppendingVars(Module *M, 757 std::multimap<std::string, GlobalVariable *> &AppendingVars, 758 std::string *ErrorMsg) { 759 if (AppendingVars.empty()) return false; // Nothing to do. 760 761 // Loop over the multimap of appending vars, processing any variables with the 762 // same name, forming a new appending global variable with both of the 763 // initializers merged together, then rewrite references to the old variables 764 // and delete them. 765 std::vector<Constant*> Inits; 766 while (AppendingVars.size() > 1) { 767 // Get the first two elements in the map... 768 std::multimap<std::string, 769 GlobalVariable*>::iterator Second = AppendingVars.begin(), First=Second++; 770 771 // If the first two elements are for different names, there is no pair... 772 // Otherwise there is a pair, so link them together... 773 if (First->first == Second->first) { 774 GlobalVariable *G1 = First->second, *G2 = Second->second; 775 const ArrayType *T1 = cast<ArrayType>(G1->getType()->getElementType()); 776 const ArrayType *T2 = cast<ArrayType>(G2->getType()->getElementType()); 777 778 // Check to see that they two arrays agree on type... 779 if (T1->getElementType() != T2->getElementType()) 780 return Error(ErrorMsg, 781 "Appending variables with different element types need to be linked!"); 782 if (G1->isConstant() != G2->isConstant()) 783 return Error(ErrorMsg, 784 "Appending variables linked with different const'ness!"); 785 786 unsigned NewSize = T1->getNumElements() + T2->getNumElements(); 787 ArrayType *NewType = ArrayType::get(T1->getElementType(), NewSize); 788 789 G1->setName(""); // Clear G1's name in case of a conflict! 790 791 // Create the new global variable... 792 GlobalVariable *NG = 793 new GlobalVariable(NewType, G1->isConstant(), G1->getLinkage(), 794 /*init*/0, First->first, M); 795 796 // Merge the initializer... 797 Inits.reserve(NewSize); 798 if (ConstantArray *I = dyn_cast<ConstantArray>(G1->getInitializer())) { 799 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i) 800 Inits.push_back(I->getOperand(i)); 801 } else { 802 assert(isa<ConstantAggregateZero>(G1->getInitializer())); 803 Constant *CV = Constant::getNullValue(T1->getElementType()); 804 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i) 805 Inits.push_back(CV); 806 } 807 if (ConstantArray *I = dyn_cast<ConstantArray>(G2->getInitializer())) { 808 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i) 809 Inits.push_back(I->getOperand(i)); 810 } else { 811 assert(isa<ConstantAggregateZero>(G2->getInitializer())); 812 Constant *CV = Constant::getNullValue(T2->getElementType()); 813 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i) 814 Inits.push_back(CV); 815 } 816 NG->setInitializer(ConstantArray::get(NewType, Inits)); 817 Inits.clear(); 818 819 // Replace any uses of the two global variables with uses of the new 820 // global... 821 822 // FIXME: This should rewrite simple/straight-forward uses such as 823 // getelementptr instructions to not use the Cast! 824 G1->replaceAllUsesWith(ConstantExpr::getBitCast(NG, G1->getType())); 825 G2->replaceAllUsesWith(ConstantExpr::getBitCast(NG, G2->getType())); 826 827 // Remove the two globals from the module now... 828 M->getGlobalList().erase(G1); 829 M->getGlobalList().erase(G2); 830 831 // Put the new global into the AppendingVars map so that we can handle 832 // linking of more than two vars... 833 Second->second = NG; 834 } 835 AppendingVars.erase(First); 836 } 837 838 return false; 839} 840 841 842// LinkModules - This function links two modules together, with the resulting 843// left module modified to be the composite of the two input modules. If an 844// error occurs, true is returned and ErrorMsg (if not null) is set to indicate 845// the problem. Upon failure, the Dest module could be in a modified state, and 846// shouldn't be relied on to be consistent. 847bool 848Linker::LinkModules(Module *Dest, Module *Src, std::string *ErrorMsg) { 849 assert(Dest != 0 && "Invalid Destination module"); 850 assert(Src != 0 && "Invalid Source Module"); 851 852 std::string DataLayout; 853 854 if (Dest->getEndianness() == Module::AnyEndianness) 855 if (Src->getEndianness() == Module::BigEndian) 856 DataLayout.append("E"); 857 else if (Src->getEndianness() == Module::LittleEndian) 858 DataLayout.append("e"); 859 if (Dest->getPointerSize() == Module::AnyPointerSize) 860 if (Src->getPointerSize() == Module::Pointer64) 861 DataLayout.append(DataLayout.length() == 0 ? "p:64:64" : "-p:64:64"); 862 else if (Src->getPointerSize() == Module::Pointer32) 863 DataLayout.append(DataLayout.length() == 0 ? "p:32:32" : "-p:32:32"); 864 if (Dest->getTargetTriple().empty()) 865 Dest->setTargetTriple(Src->getTargetTriple()); 866 Dest->setDataLayout(DataLayout); 867 868 if (Src->getDataLayout().length() > 0 && Dest->getDataLayout().length() > 0 && 869 Src->getDataLayout().compare(Dest->getDataLayout()) != 0) 870 cerr << "WARNING: Linking two modules of different data layouts!\n"; 871 if (!Src->getTargetTriple().empty() && 872 Dest->getTargetTriple() != Src->getTargetTriple()) 873 cerr << "WARNING: Linking two modules of different target triples!\n"; 874 875 if (!Src->getModuleInlineAsm().empty()) { 876 if (Dest->getModuleInlineAsm().empty()) 877 Dest->setModuleInlineAsm(Src->getModuleInlineAsm()); 878 else 879 Dest->setModuleInlineAsm(Dest->getModuleInlineAsm()+"\n"+ 880 Src->getModuleInlineAsm()); 881 } 882 883 // Update the destination module's dependent libraries list with the libraries 884 // from the source module. There's no opportunity for duplicates here as the 885 // Module ensures that duplicate insertions are discarded. 886 Module::lib_iterator SI = Src->lib_begin(); 887 Module::lib_iterator SE = Src->lib_end(); 888 while ( SI != SE ) { 889 Dest->addLibrary(*SI); 890 ++SI; 891 } 892 893 // LinkTypes - Go through the symbol table of the Src module and see if any 894 // types are named in the src module that are not named in the Dst module. 895 // Make sure there are no type name conflicts. 896 if (LinkTypes(Dest, Src, ErrorMsg)) return true; 897 898 // ValueMap - Mapping of values from what they used to be in Src, to what they 899 // are now in Dest. 900 std::map<const Value*, Value*> ValueMap; 901 902 // AppendingVars - Keep track of global variables in the destination module 903 // with appending linkage. After the module is linked together, they are 904 // appended and the module is rewritten. 905 std::multimap<std::string, GlobalVariable *> AppendingVars; 906 907 // GlobalsByName - The LLVM SymbolTable class fights our best efforts at 908 // linking by separating globals by type. Until PR411 is fixed, we replicate 909 // it's functionality here. 910 std::map<std::string, GlobalValue*> GlobalsByName; 911 912 for (Module::global_iterator I = Dest->global_begin(), E = Dest->global_end(); 913 I != E; ++I) { 914 // Add all of the appending globals already in the Dest module to 915 // AppendingVars. 916 if (I->hasAppendingLinkage()) 917 AppendingVars.insert(std::make_pair(I->getName(), I)); 918 919 // Keep track of all globals by name. 920 if (!I->hasInternalLinkage() && I->hasName()) 921 GlobalsByName[I->getName()] = I; 922 } 923 924 // Keep track of all globals by name. 925 for (Module::iterator I = Dest->begin(), E = Dest->end(); I != E; ++I) 926 if (!I->hasInternalLinkage() && I->hasName()) 927 GlobalsByName[I->getName()] = I; 928 929 // Insert all of the globals in src into the Dest module... without linking 930 // initializers (which could refer to functions not yet mapped over). 931 if (LinkGlobals(Dest, Src, ValueMap, AppendingVars, GlobalsByName, ErrorMsg)) 932 return true; 933 934 // Link the functions together between the two modules, without doing function 935 // bodies... this just adds external function prototypes to the Dest 936 // function... We do this so that when we begin processing function bodies, 937 // all of the global values that may be referenced are available in our 938 // ValueMap. 939 if (LinkFunctionProtos(Dest, Src, ValueMap, GlobalsByName, ErrorMsg)) 940 return true; 941 942 // Update the initializers in the Dest module now that all globals that may 943 // be referenced are in Dest. 944 if (LinkGlobalInits(Dest, Src, ValueMap, ErrorMsg)) return true; 945 946 // Link in the function bodies that are defined in the source module into the 947 // DestModule. This consists basically of copying the function over and 948 // fixing up references to values. 949 if (LinkFunctionBodies(Dest, Src, ValueMap, ErrorMsg)) return true; 950 951 // If there were any appending global variables, link them together now. 952 if (LinkAppendingVars(Dest, AppendingVars, ErrorMsg)) return true; 953 954 // If the source library's module id is in the dependent library list of the 955 // destination library, remove it since that module is now linked in. 956 sys::Path modId; 957 modId.set(Src->getModuleIdentifier()); 958 if (!modId.isEmpty()) 959 Dest->removeLibrary(modId.getBasename()); 960 961 return false; 962} 963 964// vim: sw=2 965