LinkModules.cpp revision 28c3cff8250b3fe2adc6479306fe7dbdb48a1bdb
1//===- lib/Linker/LinkModules.cpp - Module Linker Implementation ----------===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file implements the LLVM module linker. 11// 12// Specifically, this: 13// * Merges global variables between the two modules 14// * Uninit + Uninit = Init, Init + Uninit = Init, Init + Init = Error if != 15// * Merges functions between two modules 16// 17//===----------------------------------------------------------------------===// 18 19#include "llvm/Linker.h" 20#include "llvm/Constants.h" 21#include "llvm/DerivedTypes.h" 22#include "llvm/Module.h" 23#include "llvm/TypeSymbolTable.h" 24#include "llvm/ValueSymbolTable.h" 25#include "llvm/Instructions.h" 26#include "llvm/Assembly/Writer.h" 27#include "llvm/Support/Streams.h" 28#include "llvm/System/Path.h" 29#include <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 constants from one module to another. 273static Value *RemapOperand(const Value *In, 274 std::map<const Value*, Value*> &ValueMap) { 275 std::map<const Value*,Value*>::const_iterator I = ValueMap.find(In); 276 if (I != ValueMap.end()) 277 return I->second; 278 279 // Check to see if it's a constant that we are interested in transforming. 280 Value *Result = 0; 281 if (const Constant *CPV = dyn_cast<Constant>(In)) { 282 if ((!isa<DerivedType>(CPV->getType()) && !isa<ConstantExpr>(CPV)) || 283 isa<ConstantInt>(CPV) || isa<ConstantAggregateZero>(CPV)) 284 return const_cast<Constant*>(CPV); // Simple constants stay identical. 285 286 if (const ConstantArray *CPA = dyn_cast<ConstantArray>(CPV)) { 287 std::vector<Constant*> Operands(CPA->getNumOperands()); 288 for (unsigned i = 0, e = CPA->getNumOperands(); i != e; ++i) 289 Operands[i] =cast<Constant>(RemapOperand(CPA->getOperand(i), ValueMap)); 290 Result = ConstantArray::get(cast<ArrayType>(CPA->getType()), Operands); 291 } else if (const ConstantStruct *CPS = dyn_cast<ConstantStruct>(CPV)) { 292 std::vector<Constant*> Operands(CPS->getNumOperands()); 293 for (unsigned i = 0, e = CPS->getNumOperands(); i != e; ++i) 294 Operands[i] =cast<Constant>(RemapOperand(CPS->getOperand(i), ValueMap)); 295 Result = ConstantStruct::get(cast<StructType>(CPS->getType()), Operands); 296 } else if (isa<ConstantPointerNull>(CPV) || isa<UndefValue>(CPV)) { 297 Result = const_cast<Constant*>(CPV); 298 } else if (const ConstantVector *CP = dyn_cast<ConstantVector>(CPV)) { 299 std::vector<Constant*> Operands(CP->getNumOperands()); 300 for (unsigned i = 0, e = CP->getNumOperands(); i != e; ++i) 301 Operands[i] = cast<Constant>(RemapOperand(CP->getOperand(i), ValueMap)); 302 Result = ConstantVector::get(Operands); 303 } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CPV)) { 304 std::vector<Constant*> Ops; 305 for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) 306 Ops.push_back(cast<Constant>(RemapOperand(CE->getOperand(i),ValueMap))); 307 Result = CE->getWithOperands(Ops); 308 } else if (isa<GlobalValue>(CPV)) { 309 assert(0 && "Unmapped global?"); 310 } else { 311 assert(0 && "Unknown type of derived type constant value!"); 312 } 313 } else if (isa<InlineAsm>(In)) { 314 Result = const_cast<Value*>(In); 315 } 316 317 // Cache the mapping in our local map structure 318 if (Result) { 319 ValueMap[In] = Result; 320 return Result; 321 } 322 323 324 cerr << "LinkModules ValueMap: \n"; 325 PrintMap(ValueMap); 326 327 cerr << "Couldn't remap value: " << (void*)In << " " << *In << "\n"; 328 assert(0 && "Couldn't remap value!"); 329 return 0; 330} 331 332/// ForceRenaming - The LLVM SymbolTable class autorenames globals that conflict 333/// in the symbol table. This is good for all clients except for us. Go 334/// through the trouble to force this back. 335static void ForceRenaming(GlobalValue *GV, const std::string &Name) { 336 assert(GV->getName() != Name && "Can't force rename to self"); 337 ValueSymbolTable &ST = GV->getParent()->getValueSymbolTable(); 338 339 // If there is a conflict, rename the conflict. 340 if (GlobalValue *ConflictGV = cast_or_null<GlobalValue>(ST.lookup(Name))) { 341 assert(ConflictGV->hasInternalLinkage() && 342 "Not conflicting with a static global, should link instead!"); 343 GV->takeName(ConflictGV); 344 ConflictGV->setName(Name); // This will cause ConflictGV to get renamed 345 assert(ConflictGV->getName() != Name && "ForceRenaming didn't work"); 346 } else { 347 GV->setName(Name); // Force the name back 348 } 349} 350 351/// CopyGVAttributes - copy additional attributes (those not needed to construct 352/// a GlobalValue) from the SrcGV to the DestGV. 353static void CopyGVAttributes(GlobalValue *DestGV, const GlobalValue *SrcGV) { 354 // Use the maximum alignment, rather than just copying the alignment of SrcGV. 355 unsigned Alignment = std::max(DestGV->getAlignment(), SrcGV->getAlignment()); 356 DestGV->copyAttributesFrom(SrcGV); 357 DestGV->setAlignment(Alignment); 358} 359 360/// GetLinkageResult - This analyzes the two global values and determines what 361/// the result will look like in the destination module. In particular, it 362/// computes the resultant linkage type, computes whether the global in the 363/// source should be copied over to the destination (replacing the existing 364/// one), and computes whether this linkage is an error or not. It also performs 365/// visibility checks: we cannot link together two symbols with different 366/// visibilities. 367static bool GetLinkageResult(GlobalValue *Dest, const GlobalValue *Src, 368 GlobalValue::LinkageTypes <, bool &LinkFromSrc, 369 std::string *Err) { 370 assert((!Dest || !Src->hasInternalLinkage()) && 371 "If Src has internal linkage, Dest shouldn't be set!"); 372 if (!Dest) { 373 // Linking something to nothing. 374 LinkFromSrc = true; 375 LT = Src->getLinkage(); 376 } else if (Src->isDeclaration()) { 377 // If Src is external or if both Src & Dest are external.. Just link the 378 // external globals, we aren't adding anything. 379 if (Src->hasDLLImportLinkage()) { 380 // If one of GVs has DLLImport linkage, result should be dllimport'ed. 381 if (Dest->isDeclaration()) { 382 LinkFromSrc = true; 383 LT = Src->getLinkage(); 384 } 385 } else if (Dest->hasExternalWeakLinkage()) { 386 //If the Dest is weak, use the source linkage 387 LinkFromSrc = true; 388 LT = Src->getLinkage(); 389 } else { 390 LinkFromSrc = false; 391 LT = Dest->getLinkage(); 392 } 393 } else if (Dest->isDeclaration() && !Dest->hasDLLImportLinkage()) { 394 // If Dest is external but Src is not: 395 LinkFromSrc = true; 396 LT = Src->getLinkage(); 397 } else if (Src->hasAppendingLinkage() || Dest->hasAppendingLinkage()) { 398 if (Src->getLinkage() != Dest->getLinkage()) 399 return Error(Err, "Linking globals named '" + Src->getName() + 400 "': can only link appending global with another appending global!"); 401 LinkFromSrc = true; // Special cased. 402 LT = Src->getLinkage(); 403 } else if (Src->hasWeakLinkage() || Src->hasLinkOnceLinkage() || 404 Src->hasCommonLinkage()) { 405 // At this point we know that Dest has LinkOnce, External*, Weak, Common, 406 // or DLL* linkage. 407 if ((Dest->hasLinkOnceLinkage() && 408 (Src->hasWeakLinkage() || Src->hasCommonLinkage())) || 409 Dest->hasExternalWeakLinkage()) { 410 LinkFromSrc = true; 411 LT = Src->getLinkage(); 412 } else { 413 LinkFromSrc = false; 414 LT = Dest->getLinkage(); 415 } 416 } else if (Dest->hasWeakLinkage() || Dest->hasLinkOnceLinkage() || 417 Dest->hasCommonLinkage()) { 418 // At this point we know that Src has External* or DLL* linkage. 419 if (Src->hasExternalWeakLinkage()) { 420 LinkFromSrc = false; 421 LT = Dest->getLinkage(); 422 } else { 423 LinkFromSrc = true; 424 LT = GlobalValue::ExternalLinkage; 425 } 426 } else { 427 assert((Dest->hasExternalLinkage() || 428 Dest->hasDLLImportLinkage() || 429 Dest->hasDLLExportLinkage() || 430 Dest->hasExternalWeakLinkage()) && 431 (Src->hasExternalLinkage() || 432 Src->hasDLLImportLinkage() || 433 Src->hasDLLExportLinkage() || 434 Src->hasExternalWeakLinkage()) && 435 "Unexpected linkage type!"); 436 return Error(Err, "Linking globals named '" + Src->getName() + 437 "': symbol multiply defined!"); 438 } 439 440 // Check visibility 441 if (Dest && Src->getVisibility() != Dest->getVisibility()) 442 if (!Src->isDeclaration() && !Dest->isDeclaration()) 443 return Error(Err, "Linking globals named '" + Src->getName() + 444 "': symbols have different visibilities!"); 445 return false; 446} 447 448// LinkGlobals - Loop through the global variables in the src module and merge 449// them into the dest module. 450static bool LinkGlobals(Module *Dest, const Module *Src, 451 std::map<const Value*, Value*> &ValueMap, 452 std::multimap<std::string, GlobalVariable *> &AppendingVars, 453 std::string *Err) { 454 // Loop over all of the globals in the src module, mapping them over as we go 455 for (Module::const_global_iterator I = Src->global_begin(), E = Src->global_end(); 456 I != E; ++I) { 457 const GlobalVariable *SGV = I; 458 GlobalValue *DGV = 0; 459 460 // Check to see if may have to link the global with the global 461 if (SGV->hasName() && !SGV->hasInternalLinkage()) { 462 DGV = Dest->getGlobalVariable(SGV->getName()); 463 if (DGV && DGV->getType() != SGV->getType()) 464 // If types don't agree due to opaque types, try to resolve them. 465 RecursiveResolveTypes(SGV->getType(), DGV->getType(), 466 &Dest->getTypeSymbolTable(), ""); 467 } 468 469 // Check to see if may have to link the global with the alias 470 if (!DGV && SGV->hasName() && !SGV->hasInternalLinkage()) { 471 DGV = Dest->getNamedAlias(SGV->getName()); 472 if (DGV && DGV->getType() != SGV->getType()) 473 // If types don't agree due to opaque types, try to resolve them. 474 RecursiveResolveTypes(SGV->getType(), DGV->getType(), 475 &Dest->getTypeSymbolTable(), ""); 476 } 477 478 if (DGV && DGV->hasInternalLinkage()) 479 DGV = 0; 480 481 assert((SGV->hasInitializer() || SGV->hasExternalWeakLinkage() || 482 SGV->hasExternalLinkage() || SGV->hasDLLImportLinkage()) && 483 "Global must either be external or have an initializer!"); 484 485 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; 486 bool LinkFromSrc = false; 487 if (GetLinkageResult(DGV, SGV, NewLinkage, LinkFromSrc, Err)) 488 return true; 489 490 if (!DGV) { 491 // No linking to be performed, simply create an identical version of the 492 // symbol over in the dest module... the initializer will be filled in 493 // later by LinkGlobalInits... 494 GlobalVariable *NewDGV = 495 new GlobalVariable(SGV->getType()->getElementType(), 496 SGV->isConstant(), SGV->getLinkage(), /*init*/0, 497 SGV->getName(), Dest); 498 // Propagate alignment, visibility and section info. 499 CopyGVAttributes(NewDGV, SGV); 500 501 // If the LLVM runtime renamed the global, but it is an externally visible 502 // symbol, DGV must be an existing global with internal linkage. Rename 503 // it. 504 if (NewDGV->getName() != SGV->getName() && !NewDGV->hasInternalLinkage()) 505 ForceRenaming(NewDGV, SGV->getName()); 506 507 // Make sure to remember this mapping... 508 ValueMap[SGV] = NewDGV; 509 510 if (SGV->hasAppendingLinkage()) 511 // Keep track that this is an appending variable... 512 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV)); 513 } else if (DGV->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 // Set alignment allowing CopyGVAttributes merge it with alignment of SGV. 524 NewDGV->setAlignment(DGV->getAlignment()); 525 // Propagate alignment, section and visibility info. 526 CopyGVAttributes(NewDGV, SGV); 527 528 // Make sure to remember this mapping... 529 ValueMap[SGV] = NewDGV; 530 531 // Keep track that this is an appending variable... 532 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV)); 533 } else if (GlobalAlias *DGA = dyn_cast<GlobalAlias>(DGV)) { 534 // SGV is global, but DGV is alias. The only valid mapping is when SGV is 535 // external declaration, which is effectively a no-op. Also make sure 536 // linkage calculation was correct. 537 if (SGV->isDeclaration() && !LinkFromSrc) { 538 // Make sure to remember this mapping... 539 ValueMap[SGV] = DGA; 540 } else 541 return Error(Err, "Global-Alias Collision on '" + SGV->getName() + 542 "': symbol multiple defined"); 543 } else if (GlobalVariable *DGVar = dyn_cast<GlobalVariable>(DGV)) { 544 // Otherwise, perform the global-global mapping as instructed by 545 // GetLinkageResult. 546 if (LinkFromSrc) { 547 // Propagate alignment, section, and visibility info. 548 CopyGVAttributes(DGVar, SGV); 549 550 // If the types don't match, and if we are to link from the source, nuke 551 // DGV and create a new one of the appropriate type. 552 if (SGV->getType() != DGVar->getType()) { 553 GlobalVariable *NewDGV = 554 new GlobalVariable(SGV->getType()->getElementType(), 555 DGVar->isConstant(), DGVar->getLinkage(), 556 /*init*/0, DGVar->getName(), Dest); 557 CopyGVAttributes(NewDGV, DGVar); 558 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDGV, 559 DGVar->getType())); 560 // DGVar will conflict with NewDGV because they both had the same 561 // name. We must erase this now so ForceRenaming doesn't assert 562 // because DGV might not have internal linkage. 563 DGVar->eraseFromParent(); 564 565 // If the symbol table renamed the global, but it is an externally 566 // visible symbol, DGV must be an existing global with internal 567 // linkage. Rename it. 568 if (NewDGV->getName() != SGV->getName() && 569 !NewDGV->hasInternalLinkage()) 570 ForceRenaming(NewDGV, SGV->getName()); 571 572 DGVar = NewDGV; 573 } 574 575 // Inherit const as appropriate 576 DGVar->setConstant(SGV->isConstant()); 577 578 // Set initializer to zero, so we can link the stuff later 579 DGVar->setInitializer(0); 580 } else { 581 // Special case for const propagation 582 if (DGVar->isDeclaration() && SGV->isConstant() && !DGVar->isConstant()) 583 DGVar->setConstant(true); 584 } 585 586 // Set calculated linkage 587 DGVar->setLinkage(NewLinkage); 588 589 // Make sure to remember this mapping... 590 ValueMap[SGV] = ConstantExpr::getBitCast(DGVar, SGV->getType()); 591 } 592 } 593 return false; 594} 595 596static GlobalValue::LinkageTypes 597CalculateAliasLinkage(const GlobalValue *SGV, const GlobalValue *DGV) { 598 if (SGV->hasExternalLinkage() || DGV->hasExternalLinkage()) 599 return GlobalValue::ExternalLinkage; 600 else if (SGV->hasWeakLinkage() || DGV->hasWeakLinkage()) 601 return GlobalValue::WeakLinkage; 602 else { 603 assert(SGV->hasInternalLinkage() && DGV->hasInternalLinkage() && 604 "Unexpected linkage type"); 605 return GlobalValue::InternalLinkage; 606 } 607} 608 609// LinkAlias - Loop through the alias in the src module and link them into the 610// dest module. We're assuming, that all functions/global variables were already 611// linked in. 612static bool LinkAlias(Module *Dest, const Module *Src, 613 std::map<const Value*, Value*> &ValueMap, 614 std::string *Err) { 615 // Loop over all alias in the src module 616 for (Module::const_alias_iterator I = Src->alias_begin(), 617 E = Src->alias_end(); I != E; ++I) { 618 const GlobalAlias *SGA = I; 619 const GlobalValue *SAliasee = SGA->getAliasedGlobal(); 620 GlobalAlias *NewGA = NULL; 621 622 // Globals were already linked, thus we can just query ValueMap for variant 623 // of SAliasee in Dest. 624 std::map<const Value*,Value*>::const_iterator VMI = ValueMap.find(SAliasee); 625 assert(VMI != ValueMap.end() && "Aliasee not linked"); 626 GlobalValue* DAliasee = cast<GlobalValue>(VMI->second); 627 GlobalValue* DGV = NULL; 628 629 // Try to find something 'similar' to SGA in destination module. 630 if (!DGV && !SGA->hasInternalLinkage()) { 631 DGV = Dest->getNamedAlias(SGA->getName()); 632 633 // If types don't agree due to opaque types, try to resolve them. 634 if (DGV && DGV->getType() != SGA->getType()) 635 if (RecursiveResolveTypes(SGA->getType(), DGV->getType(), 636 &Dest->getTypeSymbolTable(), "")) 637 return Error(Err, "Alias Collision on '" + SGA->getName()+ 638 "': aliases have different types"); 639 } 640 641 if (!DGV && !SGA->hasInternalLinkage()) { 642 DGV = Dest->getGlobalVariable(SGA->getName()); 643 644 // If types don't agree due to opaque types, try to resolve them. 645 if (DGV && DGV->getType() != SGA->getType()) 646 if (RecursiveResolveTypes(SGA->getType(), DGV->getType(), 647 &Dest->getTypeSymbolTable(), "")) 648 return Error(Err, "Alias Collision on '" + SGA->getName()+ 649 "': aliases have different types"); 650 } 651 652 if (!DGV && !SGA->hasInternalLinkage()) { 653 DGV = Dest->getFunction(SGA->getName()); 654 655 // If types don't agree due to opaque types, try to resolve them. 656 if (DGV && DGV->getType() != SGA->getType()) 657 if (RecursiveResolveTypes(SGA->getType(), DGV->getType(), 658 &Dest->getTypeSymbolTable(), "")) 659 return Error(Err, "Alias Collision on '" + SGA->getName()+ 660 "': aliases have different types"); 661 } 662 663 // No linking to be performed on internal stuff. 664 if (DGV && DGV->hasInternalLinkage()) 665 DGV = NULL; 666 667 if (GlobalAlias *DGA = dyn_cast_or_null<GlobalAlias>(DGV)) { 668 // Types are known to be the same, check whether aliasees equal. As 669 // globals are already linked we just need query ValueMap to find the 670 // mapping. 671 if (DAliasee == DGA->getAliasedGlobal()) { 672 // This is just two copies of the same alias. Propagate linkage, if 673 // necessary. 674 DGA->setLinkage(CalculateAliasLinkage(SGA, DGA)); 675 676 NewGA = DGA; 677 // Proceed to 'common' steps 678 } else 679 return Error(Err, "Alias Collision on '" + SGA->getName()+ 680 "': aliases have different aliasees"); 681 } else if (GlobalVariable *DGVar = dyn_cast_or_null<GlobalVariable>(DGV)) { 682 // The only allowed way is to link alias with external declaration. 683 if (DGVar->isDeclaration()) { 684 // But only if aliasee is global too... 685 if (!isa<GlobalVariable>(DAliasee)) 686 return Error(Err, "Global-Alias Collision on '" + SGA->getName() + 687 "': aliasee is not global variable"); 688 689 NewGA = new GlobalAlias(SGA->getType(), SGA->getLinkage(), 690 SGA->getName(), DAliasee, Dest); 691 CopyGVAttributes(NewGA, SGA); 692 693 // Any uses of DGV need to change to NewGA, with cast, if needed. 694 if (SGA->getType() != DGVar->getType()) 695 DGVar->replaceAllUsesWith(ConstantExpr::getBitCast(NewGA, 696 DGVar->getType())); 697 else 698 DGVar->replaceAllUsesWith(NewGA); 699 700 // DGVar will conflict with NewGA because they both had the same 701 // name. We must erase this now so ForceRenaming doesn't assert 702 // because DGV might not have internal linkage. 703 DGVar->eraseFromParent(); 704 705 // Proceed to 'common' steps 706 } else 707 return Error(Err, "Global-Alias Collision on '" + SGA->getName() + 708 "': symbol multiple defined"); 709 } else if (Function *DF = dyn_cast_or_null<Function>(DGV)) { 710 // The only allowed way is to link alias with external declaration. 711 if (DF->isDeclaration()) { 712 // But only if aliasee is function too... 713 if (!isa<Function>(DAliasee)) 714 return Error(Err, "Function-Alias Collision on '" + SGA->getName() + 715 "': aliasee is not function"); 716 717 NewGA = new GlobalAlias(SGA->getType(), SGA->getLinkage(), 718 SGA->getName(), DAliasee, Dest); 719 CopyGVAttributes(NewGA, SGA); 720 721 // Any uses of DF need to change to NewGA, with cast, if needed. 722 if (SGA->getType() != DF->getType()) 723 DF->replaceAllUsesWith(ConstantExpr::getBitCast(NewGA, 724 DF->getType())); 725 else 726 DF->replaceAllUsesWith(NewGA); 727 728 // DF will conflict with NewGA because they both had the same 729 // name. We must erase this now so ForceRenaming doesn't assert 730 // because DF might not have internal linkage. 731 DF->eraseFromParent(); 732 733 // Proceed to 'common' steps 734 } else 735 return Error(Err, "Function-Alias Collision on '" + SGA->getName() + 736 "': symbol multiple defined"); 737 } else { 738 // No linking to be performed, simply create an identical version of the 739 // alias over in the dest module... 740 741 NewGA = new GlobalAlias(SGA->getType(), SGA->getLinkage(), 742 SGA->getName(), DAliasee, Dest); 743 CopyGVAttributes(NewGA, SGA); 744 745 // Proceed to 'common' steps 746 } 747 748 assert(NewGA && "No alias was created in destination module!"); 749 750 // If the symbol table renamed the alias, but it is an externally visible 751 // symbol, DGA must be an global value with internal linkage. Rename it. 752 if (NewGA->getName() != SGA->getName() && 753 !NewGA->hasInternalLinkage()) 754 ForceRenaming(NewGA, SGA->getName()); 755 756 // Remember this mapping so uses in the source module get remapped 757 // later by RemapOperand. 758 ValueMap[SGA] = NewGA; 759 } 760 761 return false; 762} 763 764 765// LinkGlobalInits - Update the initializers in the Dest module now that all 766// globals that may be referenced are in Dest. 767static bool LinkGlobalInits(Module *Dest, const Module *Src, 768 std::map<const Value*, Value*> &ValueMap, 769 std::string *Err) { 770 771 // Loop over all of the globals in the src module, mapping them over as we go 772 for (Module::const_global_iterator I = Src->global_begin(), 773 E = Src->global_end(); I != E; ++I) { 774 const GlobalVariable *SGV = I; 775 776 if (SGV->hasInitializer()) { // Only process initialized GV's 777 // Figure out what the initializer looks like in the dest module... 778 Constant *SInit = 779 cast<Constant>(RemapOperand(SGV->getInitializer(), ValueMap)); 780 781 GlobalVariable *DGV = 782 cast<GlobalVariable>(ValueMap[SGV]->stripPointerCasts()); 783 if (DGV->hasInitializer()) { 784 if (SGV->hasExternalLinkage()) { 785 if (DGV->getInitializer() != SInit) 786 return Error(Err, "Global Variable Collision on '" + SGV->getName() + 787 "': global variables have different initializers"); 788 } else if (DGV->hasLinkOnceLinkage() || DGV->hasWeakLinkage() || 789 DGV->hasCommonLinkage()) { 790 // Nothing is required, mapped values will take the new global 791 // automatically. 792 } else if (SGV->hasLinkOnceLinkage() || SGV->hasWeakLinkage() || 793 SGV->hasCommonLinkage()) { 794 // Nothing is required, mapped values will take the new global 795 // automatically. 796 } else if (DGV->hasAppendingLinkage()) { 797 assert(0 && "Appending linkage unimplemented!"); 798 } else { 799 assert(0 && "Unknown linkage!"); 800 } 801 } else { 802 // Copy the initializer over now... 803 DGV->setInitializer(SInit); 804 } 805 } 806 } 807 return false; 808} 809 810// LinkFunctionProtos - Link the functions together between the two modules, 811// without doing function bodies... this just adds external function prototypes 812// to the Dest function... 813// 814static bool LinkFunctionProtos(Module *Dest, const Module *Src, 815 std::map<const Value*, Value*> &ValueMap, 816 std::string *Err) { 817 // Loop over all of the functions in the src module, mapping them over 818 for (Module::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) { 819 const Function *SF = I; // SrcFunction 820 Function *DF = 0; 821 if (SF->hasName() && !SF->hasInternalLinkage()) { 822 // Check to see if may have to link the function. 823 DF = Dest->getFunction(SF->getName()); 824 if (DF && SF->getType() != DF->getType()) 825 // If types don't agree because of opaque, try to resolve them 826 RecursiveResolveTypes(SF->getType(), DF->getType(), 827 &Dest->getTypeSymbolTable(), ""); 828 } 829 830 // Check visibility 831 if (DF && !DF->hasInternalLinkage() && 832 SF->getVisibility() != DF->getVisibility()) { 833 // If one is a prototype, ignore its visibility. Prototypes are always 834 // overridden by the definition. 835 if (!SF->isDeclaration() && !DF->isDeclaration()) 836 return Error(Err, "Linking functions named '" + SF->getName() + 837 "': symbols have different visibilities!"); 838 } 839 840 if (DF && DF->hasInternalLinkage()) 841 DF = NULL; 842 843 if (DF && DF->getType() != SF->getType()) { 844 if (DF->isDeclaration() && !SF->isDeclaration()) { 845 // We have a definition of the same name but different type in the 846 // source module. Copy the prototype to the destination and replace 847 // uses of the destination's prototype with the new prototype. 848 Function *NewDF = Function::Create(SF->getFunctionType(), 849 SF->getLinkage(), 850 SF->getName(), Dest); 851 CopyGVAttributes(NewDF, SF); 852 853 // Any uses of DF need to change to NewDF, with cast 854 DF->replaceAllUsesWith(ConstantExpr::getBitCast(NewDF, DF->getType())); 855 856 // DF will conflict with NewDF because they both had the same. We must 857 // erase this now so ForceRenaming doesn't assert because DF might 858 // not have internal linkage. 859 DF->eraseFromParent(); 860 861 // If the symbol table renamed the function, but it is an externally 862 // visible symbol, DF must be an existing function with internal 863 // linkage. Rename it. 864 if (NewDF->getName() != SF->getName() && !NewDF->hasInternalLinkage()) 865 ForceRenaming(NewDF, SF->getName()); 866 867 // Remember this mapping so uses in the source module get remapped 868 // later by RemapOperand. 869 ValueMap[SF] = NewDF; 870 } else if (SF->isDeclaration()) { 871 // We have two functions of the same name but different type and the 872 // source is a declaration while the destination is not. Any use of 873 // the source must be mapped to the destination, with a cast. 874 ValueMap[SF] = ConstantExpr::getBitCast(DF, SF->getType()); 875 } else { 876 // We have two functions of the same name but different types and they 877 // are both definitions. This is an error. 878 return Error(Err, "Function '" + DF->getName() + "' defined as both '" + 879 ToStr(SF->getFunctionType(), Src) + "' and '" + 880 ToStr(DF->getFunctionType(), Dest) + "'"); 881 } 882 } else if (!DF || SF->hasInternalLinkage() || DF->hasInternalLinkage()) { 883 // Function does not already exist, simply insert an function signature 884 // identical to SF into the dest module. 885 Function *NewDF = Function::Create(SF->getFunctionType(), 886 SF->getLinkage(), 887 SF->getName(), Dest); 888 CopyGVAttributes(NewDF, SF); 889 890 // If the LLVM runtime renamed the function, but it is an externally 891 // visible symbol, DF must be an existing function with internal linkage. 892 // Rename it. 893 if (NewDF->getName() != SF->getName() && !NewDF->hasInternalLinkage()) 894 ForceRenaming(NewDF, SF->getName()); 895 896 // ... and remember this mapping... 897 ValueMap[SF] = NewDF; 898 } else if (SF->isDeclaration()) { 899 // If SF is a declaration or if both SF & DF are declarations, just link 900 // the declarations, we aren't adding anything. 901 if (SF->hasDLLImportLinkage()) { 902 if (DF->isDeclaration()) { 903 ValueMap.insert(std::make_pair(SF, DF)); 904 DF->setLinkage(SF->getLinkage()); 905 } 906 } else { 907 ValueMap[SF] = DF; 908 } 909 } else if (DF->isDeclaration() && !DF->hasDLLImportLinkage()) { 910 // If DF is external but SF is not... 911 // Link the external functions, update linkage qualifiers 912 ValueMap.insert(std::make_pair(SF, DF)); 913 DF->setLinkage(SF->getLinkage()); 914 // Visibility of prototype is overridden by vis of definition. 915 DF->setVisibility(SF->getVisibility()); 916 } else if (SF->hasWeakLinkage() || SF->hasLinkOnceLinkage() || 917 SF->hasCommonLinkage()) { 918 // At this point we know that DF has LinkOnce, Weak, or External* linkage. 919 ValueMap[SF] = DF; 920 921 // Linkonce+Weak = Weak 922 // *+External Weak = * 923 if ((DF->hasLinkOnceLinkage() && 924 (SF->hasWeakLinkage() || SF->hasCommonLinkage())) || 925 DF->hasExternalWeakLinkage()) 926 DF->setLinkage(SF->getLinkage()); 927 } else if (DF->hasWeakLinkage() || DF->hasLinkOnceLinkage() || 928 DF->hasCommonLinkage()) { 929 // At this point we know that SF has LinkOnce or External* linkage. 930 ValueMap[SF] = DF; 931 if (!SF->hasLinkOnceLinkage() && !SF->hasExternalWeakLinkage()) 932 // Don't inherit linkonce & external weak linkage 933 DF->setLinkage(SF->getLinkage()); 934 } else if (SF->getLinkage() != DF->getLinkage()) { 935 return Error(Err, "Functions named '" + SF->getName() + 936 "' have different linkage specifiers!"); 937 } else if (SF->hasExternalLinkage()) { 938 // The function is defined identically in both modules!! 939 return Error(Err, "Function '" + 940 ToStr(SF->getFunctionType(), Src) + "':\"" + 941 SF->getName() + "\" - Function is already defined!"); 942 } else { 943 assert(0 && "Unknown linkage configuration found!"); 944 } 945 } 946 return false; 947} 948 949// LinkFunctionBody - Copy the source function over into the dest function and 950// fix up references to values. At this point we know that Dest is an external 951// function, and that Src is not. 952static bool LinkFunctionBody(Function *Dest, Function *Src, 953 std::map<const Value*, Value*> &ValueMap, 954 std::string *Err) { 955 assert(Src && Dest && Dest->isDeclaration() && !Src->isDeclaration()); 956 957 // Go through and convert function arguments over, remembering the mapping. 958 Function::arg_iterator DI = Dest->arg_begin(); 959 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end(); 960 I != E; ++I, ++DI) { 961 DI->setName(I->getName()); // Copy the name information over... 962 963 // Add a mapping to our local map 964 ValueMap[I] = DI; 965 } 966 967 // Splice the body of the source function into the dest function. 968 Dest->getBasicBlockList().splice(Dest->end(), Src->getBasicBlockList()); 969 970 // At this point, all of the instructions and values of the function are now 971 // copied over. The only problem is that they are still referencing values in 972 // the Source function as operands. Loop through all of the operands of the 973 // functions and patch them up to point to the local versions... 974 // 975 for (Function::iterator BB = Dest->begin(), BE = Dest->end(); BB != BE; ++BB) 976 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) 977 for (Instruction::op_iterator OI = I->op_begin(), OE = I->op_end(); 978 OI != OE; ++OI) 979 if (!isa<Instruction>(*OI) && !isa<BasicBlock>(*OI)) 980 *OI = RemapOperand(*OI, ValueMap); 981 982 // There is no need to map the arguments anymore. 983 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end(); 984 I != E; ++I) 985 ValueMap.erase(I); 986 987 return false; 988} 989 990 991// LinkFunctionBodies - Link in the function bodies that are defined in the 992// source module into the DestModule. This consists basically of copying the 993// function over and fixing up references to values. 994static bool LinkFunctionBodies(Module *Dest, Module *Src, 995 std::map<const Value*, Value*> &ValueMap, 996 std::string *Err) { 997 998 // Loop over all of the functions in the src module, mapping them over as we 999 // go 1000 for (Module::iterator SF = Src->begin(), E = Src->end(); SF != E; ++SF) { 1001 if (!SF->isDeclaration()) { // No body if function is external 1002 Function *DF = cast<Function>(ValueMap[SF]); // Destination function 1003 1004 // DF not external SF external? 1005 if (DF->isDeclaration()) 1006 // Only provide the function body if there isn't one already. 1007 if (LinkFunctionBody(DF, SF, ValueMap, Err)) 1008 return true; 1009 } 1010 } 1011 return false; 1012} 1013 1014// LinkAppendingVars - If there were any appending global variables, link them 1015// together now. Return true on error. 1016static bool LinkAppendingVars(Module *M, 1017 std::multimap<std::string, GlobalVariable *> &AppendingVars, 1018 std::string *ErrorMsg) { 1019 if (AppendingVars.empty()) return false; // Nothing to do. 1020 1021 // Loop over the multimap of appending vars, processing any variables with the 1022 // same name, forming a new appending global variable with both of the 1023 // initializers merged together, then rewrite references to the old variables 1024 // and delete them. 1025 std::vector<Constant*> Inits; 1026 while (AppendingVars.size() > 1) { 1027 // Get the first two elements in the map... 1028 std::multimap<std::string, 1029 GlobalVariable*>::iterator Second = AppendingVars.begin(), First=Second++; 1030 1031 // If the first two elements are for different names, there is no pair... 1032 // Otherwise there is a pair, so link them together... 1033 if (First->first == Second->first) { 1034 GlobalVariable *G1 = First->second, *G2 = Second->second; 1035 const ArrayType *T1 = cast<ArrayType>(G1->getType()->getElementType()); 1036 const ArrayType *T2 = cast<ArrayType>(G2->getType()->getElementType()); 1037 1038 // Check to see that they two arrays agree on type... 1039 if (T1->getElementType() != T2->getElementType()) 1040 return Error(ErrorMsg, 1041 "Appending variables with different element types need to be linked!"); 1042 if (G1->isConstant() != G2->isConstant()) 1043 return Error(ErrorMsg, 1044 "Appending variables linked with different const'ness!"); 1045 1046 if (G1->getAlignment() != G2->getAlignment()) 1047 return Error(ErrorMsg, 1048 "Appending variables with different alignment need to be linked!"); 1049 1050 if (G1->getVisibility() != G2->getVisibility()) 1051 return Error(ErrorMsg, 1052 "Appending variables with different visibility need to be linked!"); 1053 1054 if (G1->getSection() != G2->getSection()) 1055 return Error(ErrorMsg, 1056 "Appending variables with different section name need to be linked!"); 1057 1058 unsigned NewSize = T1->getNumElements() + T2->getNumElements(); 1059 ArrayType *NewType = ArrayType::get(T1->getElementType(), NewSize); 1060 1061 G1->setName(""); // Clear G1's name in case of a conflict! 1062 1063 // Create the new global variable... 1064 GlobalVariable *NG = 1065 new GlobalVariable(NewType, G1->isConstant(), G1->getLinkage(), 1066 /*init*/0, First->first, M, G1->isThreadLocal()); 1067 1068 // Propagate alignment, visibility and section info. 1069 CopyGVAttributes(NG, G1); 1070 1071 // Merge the initializer... 1072 Inits.reserve(NewSize); 1073 if (ConstantArray *I = dyn_cast<ConstantArray>(G1->getInitializer())) { 1074 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i) 1075 Inits.push_back(I->getOperand(i)); 1076 } else { 1077 assert(isa<ConstantAggregateZero>(G1->getInitializer())); 1078 Constant *CV = Constant::getNullValue(T1->getElementType()); 1079 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i) 1080 Inits.push_back(CV); 1081 } 1082 if (ConstantArray *I = dyn_cast<ConstantArray>(G2->getInitializer())) { 1083 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i) 1084 Inits.push_back(I->getOperand(i)); 1085 } else { 1086 assert(isa<ConstantAggregateZero>(G2->getInitializer())); 1087 Constant *CV = Constant::getNullValue(T2->getElementType()); 1088 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i) 1089 Inits.push_back(CV); 1090 } 1091 NG->setInitializer(ConstantArray::get(NewType, Inits)); 1092 Inits.clear(); 1093 1094 // Replace any uses of the two global variables with uses of the new 1095 // global... 1096 1097 // FIXME: This should rewrite simple/straight-forward uses such as 1098 // getelementptr instructions to not use the Cast! 1099 G1->replaceAllUsesWith(ConstantExpr::getBitCast(NG, G1->getType())); 1100 G2->replaceAllUsesWith(ConstantExpr::getBitCast(NG, G2->getType())); 1101 1102 // Remove the two globals from the module now... 1103 M->getGlobalList().erase(G1); 1104 M->getGlobalList().erase(G2); 1105 1106 // Put the new global into the AppendingVars map so that we can handle 1107 // linking of more than two vars... 1108 Second->second = NG; 1109 } 1110 AppendingVars.erase(First); 1111 } 1112 1113 return false; 1114} 1115 1116static bool ResolveAliases(Module *Dest) { 1117 for (Module::alias_iterator I = Dest->alias_begin(), E = Dest->alias_end(); 1118 I != E; ++I) 1119 if (const GlobalValue *GV = I->resolveAliasedGlobal()) 1120 if (!GV->isDeclaration()) 1121 I->replaceAllUsesWith(const_cast<GlobalValue*>(GV)); 1122 1123 return false; 1124} 1125 1126// LinkModules - This function links two modules together, with the resulting 1127// left module modified to be the composite of the two input modules. If an 1128// error occurs, true is returned and ErrorMsg (if not null) is set to indicate 1129// the problem. Upon failure, the Dest module could be in a modified state, and 1130// shouldn't be relied on to be consistent. 1131bool 1132Linker::LinkModules(Module *Dest, Module *Src, std::string *ErrorMsg) { 1133 assert(Dest != 0 && "Invalid Destination module"); 1134 assert(Src != 0 && "Invalid Source Module"); 1135 1136 if (Dest->getDataLayout().empty()) { 1137 if (!Src->getDataLayout().empty()) { 1138 Dest->setDataLayout(Src->getDataLayout()); 1139 } else { 1140 std::string DataLayout; 1141 1142 if (Dest->getEndianness() == Module::AnyEndianness) { 1143 if (Src->getEndianness() == Module::BigEndian) 1144 DataLayout.append("E"); 1145 else if (Src->getEndianness() == Module::LittleEndian) 1146 DataLayout.append("e"); 1147 } 1148 1149 if (Dest->getPointerSize() == Module::AnyPointerSize) { 1150 if (Src->getPointerSize() == Module::Pointer64) 1151 DataLayout.append(DataLayout.length() == 0 ? "p:64:64" : "-p:64:64"); 1152 else if (Src->getPointerSize() == Module::Pointer32) 1153 DataLayout.append(DataLayout.length() == 0 ? "p:32:32" : "-p:32:32"); 1154 } 1155 Dest->setDataLayout(DataLayout); 1156 } 1157 } 1158 1159 // Copy the target triple from the source to dest if the dest's is empty. 1160 if (Dest->getTargetTriple().empty() && !Src->getTargetTriple().empty()) 1161 Dest->setTargetTriple(Src->getTargetTriple()); 1162 1163 if (!Src->getDataLayout().empty() && !Dest->getDataLayout().empty() && 1164 Src->getDataLayout() != Dest->getDataLayout()) 1165 cerr << "WARNING: Linking two modules of different data layouts!\n"; 1166 if (!Src->getTargetTriple().empty() && 1167 Dest->getTargetTriple() != Src->getTargetTriple()) 1168 cerr << "WARNING: Linking two modules of different target triples!\n"; 1169 1170 // Append the module inline asm string. 1171 if (!Src->getModuleInlineAsm().empty()) { 1172 if (Dest->getModuleInlineAsm().empty()) 1173 Dest->setModuleInlineAsm(Src->getModuleInlineAsm()); 1174 else 1175 Dest->setModuleInlineAsm(Dest->getModuleInlineAsm()+"\n"+ 1176 Src->getModuleInlineAsm()); 1177 } 1178 1179 // Update the destination module's dependent libraries list with the libraries 1180 // from the source module. There's no opportunity for duplicates here as the 1181 // Module ensures that duplicate insertions are discarded. 1182 for (Module::lib_iterator SI = Src->lib_begin(), SE = Src->lib_end(); 1183 SI != SE; ++SI) 1184 Dest->addLibrary(*SI); 1185 1186 // LinkTypes - Go through the symbol table of the Src module and see if any 1187 // types are named in the src module that are not named in the Dst module. 1188 // Make sure there are no type name conflicts. 1189 if (LinkTypes(Dest, Src, ErrorMsg)) 1190 return true; 1191 1192 // ValueMap - Mapping of values from what they used to be in Src, to what they 1193 // are now in Dest. 1194 std::map<const Value*, Value*> ValueMap; 1195 1196 // AppendingVars - Keep track of global variables in the destination module 1197 // with appending linkage. After the module is linked together, they are 1198 // appended and the module is rewritten. 1199 std::multimap<std::string, GlobalVariable *> AppendingVars; 1200 for (Module::global_iterator I = Dest->global_begin(), E = Dest->global_end(); 1201 I != E; ++I) { 1202 // Add all of the appending globals already in the Dest module to 1203 // AppendingVars. 1204 if (I->hasAppendingLinkage()) 1205 AppendingVars.insert(std::make_pair(I->getName(), I)); 1206 } 1207 1208 // Insert all of the globals in src into the Dest module... without linking 1209 // initializers (which could refer to functions not yet mapped over). 1210 if (LinkGlobals(Dest, Src, ValueMap, AppendingVars, ErrorMsg)) 1211 return true; 1212 1213 // Link the functions together between the two modules, without doing function 1214 // bodies... this just adds external function prototypes to the Dest 1215 // function... We do this so that when we begin processing function bodies, 1216 // all of the global values that may be referenced are available in our 1217 // ValueMap. 1218 if (LinkFunctionProtos(Dest, Src, ValueMap, ErrorMsg)) 1219 return true; 1220 1221 // If there were any alias, link them now. We really need to do this now, 1222 // because all of the aliases that may be referenced need to be available in 1223 // ValueMap 1224 if (LinkAlias(Dest, Src, ValueMap, ErrorMsg)) return true; 1225 1226 // Update the initializers in the Dest module now that all globals that may 1227 // be referenced are in Dest. 1228 if (LinkGlobalInits(Dest, Src, ValueMap, ErrorMsg)) return true; 1229 1230 // Link in the function bodies that are defined in the source module into the 1231 // DestModule. This consists basically of copying the function over and 1232 // fixing up references to values. 1233 if (LinkFunctionBodies(Dest, Src, ValueMap, ErrorMsg)) return true; 1234 1235 // If there were any appending global variables, link them together now. 1236 if (LinkAppendingVars(Dest, AppendingVars, ErrorMsg)) return true; 1237 1238 // Resolve all uses of aliases with aliasees 1239 if (ResolveAliases(Dest)) return true; 1240 1241 // If the source library's module id is in the dependent library list of the 1242 // destination library, remove it since that module is now linked in. 1243 sys::Path modId; 1244 modId.set(Src->getModuleIdentifier()); 1245 if (!modId.isEmpty()) 1246 Dest->removeLibrary(modId.getBasename()); 1247 1248 return false; 1249} 1250 1251// vim: sw=2 1252