LinkModules.cpp revision 8219262b9d2c0a936377c9287545ddf14b1b460d
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 // Propagate alignment, visibility and section info. 355 DestGV->setAlignment(std::max(DestGV->getAlignment(), SrcGV->getAlignment())); 356 DestGV->setSection(SrcGV->getSection()); 357 DestGV->setVisibility(SrcGV->getVisibility()); 358 if (const Function *SrcF = dyn_cast<Function>(SrcGV)) { 359 Function *DestF = cast<Function>(DestGV); 360 DestF->setCallingConv(SrcF->getCallingConv()); 361 DestF->setParamAttrs(SrcF->getParamAttrs()); 362 if (SrcF->hasCollector()) 363 DestF->setCollector(SrcF->getCollector()); 364 } else if (const GlobalVariable *SrcVar = dyn_cast<GlobalVariable>(SrcGV)) { 365 GlobalVariable *DestVar = cast<GlobalVariable>(DestGV); 366 DestVar->setThreadLocal(SrcVar->isThreadLocal()); 367 } 368} 369 370/// GetLinkageResult - This analyzes the two global values and determines what 371/// the result will look like in the destination module. In particular, it 372/// computes the resultant linkage type, computes whether the global in the 373/// source should be copied over to the destination (replacing the existing 374/// one), and computes whether this linkage is an error or not. It also performs 375/// visibility checks: we cannot link together two symbols with different 376/// visibilities. 377static bool GetLinkageResult(GlobalValue *Dest, const GlobalValue *Src, 378 GlobalValue::LinkageTypes <, bool &LinkFromSrc, 379 std::string *Err) { 380 assert((!Dest || !Src->hasInternalLinkage()) && 381 "If Src has internal linkage, Dest shouldn't be set!"); 382 if (!Dest) { 383 // Linking something to nothing. 384 LinkFromSrc = true; 385 LT = Src->getLinkage(); 386 } else if (Src->isDeclaration()) { 387 // If Src is external or if both Src & Dest are external.. Just link the 388 // external globals, we aren't adding anything. 389 if (Src->hasDLLImportLinkage()) { 390 // If one of GVs has DLLImport linkage, result should be dllimport'ed. 391 if (Dest->isDeclaration()) { 392 LinkFromSrc = true; 393 LT = Src->getLinkage(); 394 } 395 } else if (Dest->hasExternalWeakLinkage()) { 396 //If the Dest is weak, use the source linkage 397 LinkFromSrc = true; 398 LT = Src->getLinkage(); 399 } else { 400 LinkFromSrc = false; 401 LT = Dest->getLinkage(); 402 } 403 } else if (Dest->isDeclaration() && !Dest->hasDLLImportLinkage()) { 404 // If Dest is external but Src is not: 405 LinkFromSrc = true; 406 LT = Src->getLinkage(); 407 } else if (Src->hasAppendingLinkage() || Dest->hasAppendingLinkage()) { 408 if (Src->getLinkage() != Dest->getLinkage()) 409 return Error(Err, "Linking globals named '" + Src->getName() + 410 "': can only link appending global with another appending global!"); 411 LinkFromSrc = true; // Special cased. 412 LT = Src->getLinkage(); 413 } else if (Src->hasWeakLinkage() || Src->hasLinkOnceLinkage()) { 414 // At this point we know that Dest has LinkOnce, External*, Weak, or 415 // DLL* linkage. 416 if ((Dest->hasLinkOnceLinkage() && Src->hasWeakLinkage()) || 417 Dest->hasExternalWeakLinkage()) { 418 LinkFromSrc = true; 419 LT = Src->getLinkage(); 420 } else { 421 LinkFromSrc = false; 422 LT = Dest->getLinkage(); 423 } 424 } else if (Dest->hasWeakLinkage() || Dest->hasLinkOnceLinkage()) { 425 // At this point we know that Src has External* or DLL* linkage. 426 if (Src->hasExternalWeakLinkage()) { 427 LinkFromSrc = false; 428 LT = Dest->getLinkage(); 429 } else { 430 LinkFromSrc = true; 431 LT = GlobalValue::ExternalLinkage; 432 } 433 } else { 434 assert((Dest->hasExternalLinkage() || 435 Dest->hasDLLImportLinkage() || 436 Dest->hasDLLExportLinkage() || 437 Dest->hasExternalWeakLinkage()) && 438 (Src->hasExternalLinkage() || 439 Src->hasDLLImportLinkage() || 440 Src->hasDLLExportLinkage() || 441 Src->hasExternalWeakLinkage()) && 442 "Unexpected linkage type!"); 443 return Error(Err, "Linking globals named '" + Src->getName() + 444 "': symbol multiply defined!"); 445 } 446 447 // Check visibility 448 if (Dest && Src->getVisibility() != Dest->getVisibility()) 449 if (!Src->isDeclaration() && !Dest->isDeclaration()) 450 return Error(Err, "Linking globals named '" + Src->getName() + 451 "': symbols have different visibilities!"); 452 return false; 453} 454 455// LinkGlobals - Loop through the global variables in the src module and merge 456// them into the dest module. 457static bool LinkGlobals(Module *Dest, const Module *Src, 458 std::map<const Value*, Value*> &ValueMap, 459 std::multimap<std::string, GlobalVariable *> &AppendingVars, 460 std::string *Err) { 461 // Loop over all of the globals in the src module, mapping them over as we go 462 for (Module::const_global_iterator I = Src->global_begin(), E = Src->global_end(); 463 I != E; ++I) { 464 const GlobalVariable *SGV = I; 465 GlobalValue *DGV = 0; 466 467 // Check to see if may have to link the global with the global 468 if (SGV->hasName() && !SGV->hasInternalLinkage()) { 469 DGV = Dest->getGlobalVariable(SGV->getName()); 470 if (DGV && DGV->getType() != SGV->getType()) 471 // If types don't agree due to opaque types, try to resolve them. 472 RecursiveResolveTypes(SGV->getType(), DGV->getType(), 473 &Dest->getTypeSymbolTable(), ""); 474 } 475 476 // Check to see if may have to link the global with the alias 477 if (!DGV && SGV->hasName() && !SGV->hasInternalLinkage()) { 478 DGV = Dest->getNamedAlias(SGV->getName()); 479 if (DGV && DGV->getType() != SGV->getType()) 480 // If types don't agree due to opaque types, try to resolve them. 481 RecursiveResolveTypes(SGV->getType(), DGV->getType(), 482 &Dest->getTypeSymbolTable(), ""); 483 } 484 485 if (DGV && DGV->hasInternalLinkage()) 486 DGV = 0; 487 488 assert((SGV->hasInitializer() || SGV->hasExternalWeakLinkage() || 489 SGV->hasExternalLinkage() || SGV->hasDLLImportLinkage()) && 490 "Global must either be external or have an initializer!"); 491 492 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; 493 bool LinkFromSrc = false; 494 if (GetLinkageResult(DGV, SGV, NewLinkage, LinkFromSrc, Err)) 495 return true; 496 497 if (!DGV) { 498 // No linking to be performed, simply create an identical version of the 499 // symbol over in the dest module... the initializer will be filled in 500 // later by LinkGlobalInits... 501 GlobalVariable *NewDGV = 502 new GlobalVariable(SGV->getType()->getElementType(), 503 SGV->isConstant(), SGV->getLinkage(), /*init*/0, 504 SGV->getName(), Dest); 505 // Propagate alignment, visibility and section info. 506 CopyGVAttributes(NewDGV, SGV); 507 508 // If the LLVM runtime renamed the global, but it is an externally visible 509 // symbol, DGV must be an existing global with internal linkage. Rename 510 // it. 511 if (NewDGV->getName() != SGV->getName() && !NewDGV->hasInternalLinkage()) 512 ForceRenaming(NewDGV, SGV->getName()); 513 514 // Make sure to remember this mapping... 515 ValueMap[SGV] = NewDGV; 516 517 if (SGV->hasAppendingLinkage()) 518 // Keep track that this is an appending variable... 519 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV)); 520 } else if (DGV->hasAppendingLinkage()) { 521 // No linking is performed yet. Just insert a new copy of the global, and 522 // keep track of the fact that it is an appending variable in the 523 // AppendingVars map. The name is cleared out so that no linkage is 524 // performed. 525 GlobalVariable *NewDGV = 526 new GlobalVariable(SGV->getType()->getElementType(), 527 SGV->isConstant(), SGV->getLinkage(), /*init*/0, 528 "", Dest); 529 530 // Set alignment allowing CopyGVAttributes merge it with alignment of SGV. 531 NewDGV->setAlignment(DGV->getAlignment()); 532 // Propagate alignment, section and visibility info. 533 CopyGVAttributes(NewDGV, SGV); 534 535 // Make sure to remember this mapping... 536 ValueMap[SGV] = NewDGV; 537 538 // Keep track that this is an appending variable... 539 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV)); 540 } else if (GlobalAlias *DGA = dyn_cast<GlobalAlias>(DGV)) { 541 // SGV is global, but DGV is alias. The only valid mapping is when SGV is 542 // external declaration, which is effectively a no-op. Also make sure 543 // linkage calculation was correct. 544 if (SGV->isDeclaration() && !LinkFromSrc) { 545 // Make sure to remember this mapping... 546 ValueMap[SGV] = DGA; 547 } else 548 return Error(Err, "Global-Alias Collision on '" + SGV->getName() + 549 "': symbol multiple defined"); 550 } else if (GlobalVariable *DGVar = dyn_cast<GlobalVariable>(DGV)) { 551 // Otherwise, perform the global-global mapping as instructed by 552 // GetLinkageResult. 553 if (LinkFromSrc) { 554 // Propagate alignment, section, and visibility info. 555 CopyGVAttributes(DGVar, SGV); 556 557 // If the types don't match, and if we are to link from the source, nuke 558 // DGV and create a new one of the appropriate type. 559 if (SGV->getType() != DGVar->getType()) { 560 GlobalVariable *NewDGV = 561 new GlobalVariable(SGV->getType()->getElementType(), 562 DGVar->isConstant(), DGVar->getLinkage(), 563 /*init*/0, DGVar->getName(), Dest); 564 CopyGVAttributes(NewDGV, DGVar); 565 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDGV, 566 DGVar->getType())); 567 // DGVar will conflict with NewDGV because they both had the same 568 // name. We must erase this now so ForceRenaming doesn't assert 569 // because DGV might not have internal linkage. 570 DGVar->eraseFromParent(); 571 572 // If the symbol table renamed the global, but it is an externally 573 // visible symbol, DGV must be an existing global with internal 574 // linkage. Rename it. 575 if (NewDGV->getName() != SGV->getName() && 576 !NewDGV->hasInternalLinkage()) 577 ForceRenaming(NewDGV, SGV->getName()); 578 579 DGVar = NewDGV; 580 } 581 582 // Inherit const as appropriate 583 DGVar->setConstant(SGV->isConstant()); 584 585 // Set initializer to zero, so we can link the stuff later 586 DGVar->setInitializer(0); 587 } else { 588 // Special case for const propagation 589 if (DGVar->isDeclaration() && SGV->isConstant() && !DGVar->isConstant()) 590 DGVar->setConstant(true); 591 } 592 593 // Set calculated linkage 594 DGVar->setLinkage(NewLinkage); 595 596 // Make sure to remember this mapping... 597 ValueMap[SGV] = ConstantExpr::getBitCast(DGVar, SGV->getType()); 598 } 599 } 600 return false; 601} 602 603static GlobalValue::LinkageTypes 604CalculateAliasLinkage(const GlobalValue *SGV, const GlobalValue *DGV) { 605 if (SGV->hasExternalLinkage() || DGV->hasExternalLinkage()) 606 return GlobalValue::ExternalLinkage; 607 else if (SGV->hasWeakLinkage() || DGV->hasWeakLinkage()) 608 return GlobalValue::WeakLinkage; 609 else { 610 assert(SGV->hasInternalLinkage() && DGV->hasInternalLinkage() && 611 "Unexpected linkage type"); 612 return GlobalValue::InternalLinkage; 613 } 614} 615 616// LinkAlias - Loop through the alias in the src module and link them into the 617// dest module. We're assuming, that all functions/global variables were already 618// linked in. 619static bool LinkAlias(Module *Dest, const Module *Src, 620 std::map<const Value*, Value*> &ValueMap, 621 std::string *Err) { 622 // Loop over all alias in the src module 623 for (Module::const_alias_iterator I = Src->alias_begin(), 624 E = Src->alias_end(); I != E; ++I) { 625 const GlobalAlias *SGA = I; 626 const GlobalValue *SAliasee = SGA->getAliasedGlobal(); 627 GlobalAlias *NewGA = NULL; 628 629 // Globals were already linked, thus we can just query ValueMap for variant 630 // of SAliasee in Dest 631 std::map<const Value*,Value*>::const_iterator VMI = ValueMap.find(SAliasee); 632 assert(VMI != ValueMap.end() && "Aliasee not linked"); 633 GlobalValue* DAliasee = cast<GlobalValue>(VMI->second); 634 635 // Try to find something 'similar' to SGA in destination module. 636 if (GlobalAlias *DGA = Dest->getNamedAlias(SGA->getName())) { 637 // If types don't agree due to opaque types, try to resolve them. 638 if (RecursiveResolveTypes(SGA->getType(), DGA->getType(), 639 &Dest->getTypeSymbolTable(), "")) 640 return Error(Err, "Alias Collision on '" + SGA->getName()+ 641 "': aliases have different types"); 642 643 // Now types are known to be the same, check whether aliasees equal. As 644 // globals are already linked we just need query ValueMap to find the 645 // mapping. 646 if (DAliasee == DGA->getAliasedGlobal()) { 647 // This is just two copies of the same alias. Propagate linkage, if 648 // necessary. 649 DGA->setLinkage(CalculateAliasLinkage(SGA, DGA)); 650 651 NewGA = DGA; 652 // Proceed to 'common' steps 653 } else 654 return Error(Err, "Alias Collision on '" + SGA->getName()+ 655 "': aliases have different aliasees"); 656 } else if (GlobalVariable *DGV = Dest->getGlobalVariable(SGA->getName())) { 657 RecursiveResolveTypes(SGA->getType(), DGV->getType(), 658 &Dest->getTypeSymbolTable(), ""); 659 660 // The only allowed way is to link alias with external declaration. 661 if (DGV->isDeclaration()) { 662 // But only if aliasee is global too... 663 if (!isa<GlobalVariable>(DAliasee)) 664 return Error(Err, "Global-Alias Collision on '" + SGA->getName() + 665 "': aliasee is not global variable"); 666 667 NewGA = new GlobalAlias(SGA->getType(), SGA->getLinkage(), 668 SGA->getName(), DAliasee, Dest); 669 CopyGVAttributes(NewGA, SGA); 670 671 // Any uses of DGV need to change to NewGA, with cast, if needed. 672 if (SGA->getType() != DGV->getType()) 673 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewGA, 674 DGV->getType())); 675 else 676 DGV->replaceAllUsesWith(NewGA); 677 678 // DGV will conflict with NewGA because they both had the same 679 // name. We must erase this now so ForceRenaming doesn't assert 680 // because DGV might not have internal linkage. 681 DGV->eraseFromParent(); 682 683 // Proceed to 'common' steps 684 } else 685 return Error(Err, "Global-Alias Collision on '" + SGA->getName() + 686 "': symbol multiple defined"); 687 } else if (Function *DF = Dest->getFunction(SGA->getName())) { 688 RecursiveResolveTypes(SGA->getType(), DF->getType(), 689 &Dest->getTypeSymbolTable(), ""); 690 691 // The only allowed way is to link alias with external declaration. 692 if (DF->isDeclaration()) { 693 // But only if aliasee is function too... 694 if (!isa<Function>(DAliasee)) 695 return Error(Err, "Function-Alias Collision on '" + SGA->getName() + 696 "': aliasee is not function"); 697 698 NewGA = new GlobalAlias(SGA->getType(), SGA->getLinkage(), 699 SGA->getName(), DAliasee, Dest); 700 CopyGVAttributes(NewGA, SGA); 701 702 // Any uses of DF need to change to NewGA, with cast, if needed. 703 if (SGA->getType() != DF->getType()) 704 DF->replaceAllUsesWith(ConstantExpr::getBitCast(NewGA, 705 DF->getType())); 706 else 707 DF->replaceAllUsesWith(NewGA); 708 709 // DF will conflict with NewGA because they both had the same 710 // name. We must erase this now so ForceRenaming doesn't assert 711 // because DF might not have internal linkage. 712 DF->eraseFromParent(); 713 714 // Proceed to 'common' steps 715 } else 716 return Error(Err, "Function-Alias Collision on '" + SGA->getName() + 717 "': symbol multiple defined"); 718 } else { 719 // Nothing similar found, just copy alias into destination module. 720 721 NewGA = new GlobalAlias(SGA->getType(), SGA->getLinkage(), 722 SGA->getName(), DAliasee, Dest); 723 CopyGVAttributes(NewGA, SGA); 724 725 // Proceed to 'common' steps 726 } 727 728 assert(NewGA && "No alias was created in destination module!"); 729 730 // If the symbol table renamed the alias, but it is an externally visible 731 // symbol, DGV must be an global value with internal linkage. Rename it. 732 if (NewGA->getName() != SGA->getName() && 733 !NewGA->hasInternalLinkage()) 734 ForceRenaming(NewGA, SGA->getName()); 735 736 // Remember this mapping so uses in the source module get remapped 737 // later by RemapOperand. 738 ValueMap[SGA] = NewGA; 739 } 740 741 return false; 742} 743 744 745// LinkGlobalInits - Update the initializers in the Dest module now that all 746// globals that may be referenced are in Dest. 747static bool LinkGlobalInits(Module *Dest, const Module *Src, 748 std::map<const Value*, Value*> &ValueMap, 749 std::string *Err) { 750 751 // Loop over all of the globals in the src module, mapping them over as we go 752 for (Module::const_global_iterator I = Src->global_begin(), 753 E = Src->global_end(); I != E; ++I) { 754 const GlobalVariable *SGV = I; 755 756 if (SGV->hasInitializer()) { // Only process initialized GV's 757 // Figure out what the initializer looks like in the dest module... 758 Constant *SInit = 759 cast<Constant>(RemapOperand(SGV->getInitializer(), ValueMap)); 760 761 GlobalVariable *DGV = cast<GlobalVariable>(ValueMap[SGV]); 762 if (DGV->hasInitializer()) { 763 if (SGV->hasExternalLinkage()) { 764 if (DGV->getInitializer() != SInit) 765 return Error(Err, "Global Variable Collision on '" + SGV->getName() + 766 "': global variables have different initializers"); 767 } else if (DGV->hasLinkOnceLinkage() || DGV->hasWeakLinkage()) { 768 // Nothing is required, mapped values will take the new global 769 // automatically. 770 } else if (SGV->hasLinkOnceLinkage() || SGV->hasWeakLinkage()) { 771 // Nothing is required, mapped values will take the new global 772 // automatically. 773 } else if (DGV->hasAppendingLinkage()) { 774 assert(0 && "Appending linkage unimplemented!"); 775 } else { 776 assert(0 && "Unknown linkage!"); 777 } 778 } else { 779 // Copy the initializer over now... 780 DGV->setInitializer(SInit); 781 } 782 } 783 } 784 return false; 785} 786 787// LinkFunctionProtos - Link the functions together between the two modules, 788// without doing function bodies... this just adds external function prototypes 789// to the Dest function... 790// 791static bool LinkFunctionProtos(Module *Dest, const Module *Src, 792 std::map<const Value*, Value*> &ValueMap, 793 std::string *Err) { 794 // Loop over all of the functions in the src module, mapping them over 795 for (Module::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) { 796 const Function *SF = I; // SrcFunction 797 Function *DF = 0; 798 if (SF->hasName() && !SF->hasInternalLinkage()) { 799 // Check to see if may have to link the function. 800 DF = Dest->getFunction(SF->getName()); 801 if (DF && SF->getType() != DF->getType()) 802 // If types don't agree because of opaque, try to resolve them 803 RecursiveResolveTypes(SF->getType(), DF->getType(), 804 &Dest->getTypeSymbolTable(), ""); 805 } 806 807 // Check visibility 808 if (DF && !DF->hasInternalLinkage() && 809 SF->getVisibility() != DF->getVisibility()) { 810 // If one is a prototype, ignore its visibility. Prototypes are always 811 // overridden by the definition. 812 if (!SF->isDeclaration() && !DF->isDeclaration()) 813 return Error(Err, "Linking functions named '" + SF->getName() + 814 "': symbols have different visibilities!"); 815 } 816 817 if (DF && DF->hasInternalLinkage()) 818 DF = NULL; 819 820 if (DF && DF->getType() != SF->getType()) { 821 if (DF->isDeclaration() && !SF->isDeclaration()) { 822 // We have a definition of the same name but different type in the 823 // source module. Copy the prototype to the destination and replace 824 // uses of the destination's prototype with the new prototype. 825 Function *NewDF = new Function(SF->getFunctionType(), SF->getLinkage(), 826 SF->getName(), Dest); 827 CopyGVAttributes(NewDF, SF); 828 829 // Any uses of DF need to change to NewDF, with cast 830 DF->replaceAllUsesWith(ConstantExpr::getBitCast(NewDF, DF->getType())); 831 832 // DF will conflict with NewDF because they both had the same. We must 833 // erase this now so ForceRenaming doesn't assert because DF might 834 // not have internal linkage. 835 DF->eraseFromParent(); 836 837 // If the symbol table renamed the function, but it is an externally 838 // visible symbol, DF must be an existing function with internal 839 // linkage. Rename it. 840 if (NewDF->getName() != SF->getName() && !NewDF->hasInternalLinkage()) 841 ForceRenaming(NewDF, SF->getName()); 842 843 // Remember this mapping so uses in the source module get remapped 844 // later by RemapOperand. 845 ValueMap[SF] = NewDF; 846 } else if (SF->isDeclaration()) { 847 // We have two functions of the same name but different type and the 848 // source is a declaration while the destination is not. Any use of 849 // the source must be mapped to the destination, with a cast. 850 ValueMap[SF] = ConstantExpr::getBitCast(DF, SF->getType()); 851 } else { 852 // We have two functions of the same name but different types and they 853 // are both definitions. This is an error. 854 return Error(Err, "Function '" + DF->getName() + "' defined as both '" + 855 ToStr(SF->getFunctionType(), Src) + "' and '" + 856 ToStr(DF->getFunctionType(), Dest) + "'"); 857 } 858 } else if (!DF || SF->hasInternalLinkage() || DF->hasInternalLinkage()) { 859 // Function does not already exist, simply insert an function signature 860 // identical to SF into the dest module. 861 Function *NewDF = new Function(SF->getFunctionType(), SF->getLinkage(), 862 SF->getName(), Dest); 863 CopyGVAttributes(NewDF, SF); 864 865 // If the LLVM runtime renamed the function, but it is an externally 866 // visible symbol, DF must be an existing function with internal linkage. 867 // Rename it. 868 if (NewDF->getName() != SF->getName() && !NewDF->hasInternalLinkage()) 869 ForceRenaming(NewDF, SF->getName()); 870 871 // ... and remember this mapping... 872 ValueMap[SF] = NewDF; 873 } else if (SF->isDeclaration()) { 874 // If SF is a declaration or if both SF & DF are declarations, just link 875 // the declarations, we aren't adding anything. 876 if (SF->hasDLLImportLinkage()) { 877 if (DF->isDeclaration()) { 878 ValueMap.insert(std::make_pair(SF, DF)); 879 DF->setLinkage(SF->getLinkage()); 880 } 881 } else { 882 ValueMap[SF] = DF; 883 } 884 } else if (DF->isDeclaration() && !DF->hasDLLImportLinkage()) { 885 // If DF is external but SF is not... 886 // Link the external functions, update linkage qualifiers 887 ValueMap.insert(std::make_pair(SF, DF)); 888 DF->setLinkage(SF->getLinkage()); 889 // Visibility of prototype is overridden by vis of definition. 890 DF->setVisibility(SF->getVisibility()); 891 } else if (SF->hasWeakLinkage() || SF->hasLinkOnceLinkage()) { 892 // At this point we know that DF has LinkOnce, Weak, or External* linkage. 893 ValueMap[SF] = DF; 894 895 // Linkonce+Weak = Weak 896 // *+External Weak = * 897 if ((DF->hasLinkOnceLinkage() && SF->hasWeakLinkage()) || 898 DF->hasExternalWeakLinkage()) 899 DF->setLinkage(SF->getLinkage()); 900 } else if (DF->hasWeakLinkage() || DF->hasLinkOnceLinkage()) { 901 // At this point we know that SF has LinkOnce or External* linkage. 902 ValueMap[SF] = DF; 903 if (!SF->hasLinkOnceLinkage() && !SF->hasExternalWeakLinkage()) 904 // Don't inherit linkonce & external weak linkage 905 DF->setLinkage(SF->getLinkage()); 906 } else if (SF->getLinkage() != DF->getLinkage()) { 907 return Error(Err, "Functions named '" + SF->getName() + 908 "' have different linkage specifiers!"); 909 } else if (SF->hasExternalLinkage()) { 910 // The function is defined identically in both modules!! 911 return Error(Err, "Function '" + 912 ToStr(SF->getFunctionType(), Src) + "':\"" + 913 SF->getName() + "\" - Function is already defined!"); 914 } else { 915 assert(0 && "Unknown linkage configuration found!"); 916 } 917 } 918 return false; 919} 920 921// LinkFunctionBody - Copy the source function over into the dest function and 922// fix up references to values. At this point we know that Dest is an external 923// function, and that Src is not. 924static bool LinkFunctionBody(Function *Dest, Function *Src, 925 std::map<const Value*, Value*> &ValueMap, 926 std::string *Err) { 927 assert(Src && Dest && Dest->isDeclaration() && !Src->isDeclaration()); 928 929 // Go through and convert function arguments over, remembering the mapping. 930 Function::arg_iterator DI = Dest->arg_begin(); 931 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end(); 932 I != E; ++I, ++DI) { 933 DI->setName(I->getName()); // Copy the name information over... 934 935 // Add a mapping to our local map 936 ValueMap[I] = DI; 937 } 938 939 // Splice the body of the source function into the dest function. 940 Dest->getBasicBlockList().splice(Dest->end(), Src->getBasicBlockList()); 941 942 // At this point, all of the instructions and values of the function are now 943 // copied over. The only problem is that they are still referencing values in 944 // the Source function as operands. Loop through all of the operands of the 945 // functions and patch them up to point to the local versions... 946 // 947 for (Function::iterator BB = Dest->begin(), BE = Dest->end(); BB != BE; ++BB) 948 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) 949 for (Instruction::op_iterator OI = I->op_begin(), OE = I->op_end(); 950 OI != OE; ++OI) 951 if (!isa<Instruction>(*OI) && !isa<BasicBlock>(*OI)) 952 *OI = RemapOperand(*OI, ValueMap); 953 954 // There is no need to map the arguments anymore. 955 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end(); 956 I != E; ++I) 957 ValueMap.erase(I); 958 959 return false; 960} 961 962 963// LinkFunctionBodies - Link in the function bodies that are defined in the 964// source module into the DestModule. This consists basically of copying the 965// function over and fixing up references to values. 966static bool LinkFunctionBodies(Module *Dest, Module *Src, 967 std::map<const Value*, Value*> &ValueMap, 968 std::string *Err) { 969 970 // Loop over all of the functions in the src module, mapping them over as we 971 // go 972 for (Module::iterator SF = Src->begin(), E = Src->end(); SF != E; ++SF) { 973 if (!SF->isDeclaration()) { // No body if function is external 974 Function *DF = cast<Function>(ValueMap[SF]); // Destination function 975 976 // DF not external SF external? 977 if (DF->isDeclaration()) 978 // Only provide the function body if there isn't one already. 979 if (LinkFunctionBody(DF, SF, ValueMap, Err)) 980 return true; 981 } 982 } 983 return false; 984} 985 986// LinkAppendingVars - If there were any appending global variables, link them 987// together now. Return true on error. 988static bool LinkAppendingVars(Module *M, 989 std::multimap<std::string, GlobalVariable *> &AppendingVars, 990 std::string *ErrorMsg) { 991 if (AppendingVars.empty()) return false; // Nothing to do. 992 993 // Loop over the multimap of appending vars, processing any variables with the 994 // same name, forming a new appending global variable with both of the 995 // initializers merged together, then rewrite references to the old variables 996 // and delete them. 997 std::vector<Constant*> Inits; 998 while (AppendingVars.size() > 1) { 999 // Get the first two elements in the map... 1000 std::multimap<std::string, 1001 GlobalVariable*>::iterator Second = AppendingVars.begin(), First=Second++; 1002 1003 // If the first two elements are for different names, there is no pair... 1004 // Otherwise there is a pair, so link them together... 1005 if (First->first == Second->first) { 1006 GlobalVariable *G1 = First->second, *G2 = Second->second; 1007 const ArrayType *T1 = cast<ArrayType>(G1->getType()->getElementType()); 1008 const ArrayType *T2 = cast<ArrayType>(G2->getType()->getElementType()); 1009 1010 // Check to see that they two arrays agree on type... 1011 if (T1->getElementType() != T2->getElementType()) 1012 return Error(ErrorMsg, 1013 "Appending variables with different element types need to be linked!"); 1014 if (G1->isConstant() != G2->isConstant()) 1015 return Error(ErrorMsg, 1016 "Appending variables linked with different const'ness!"); 1017 1018 if (G1->getAlignment() != G2->getAlignment()) 1019 return Error(ErrorMsg, 1020 "Appending variables with different alignment need to be linked!"); 1021 1022 if (G1->getVisibility() != G2->getVisibility()) 1023 return Error(ErrorMsg, 1024 "Appending variables with different visibility need to be linked!"); 1025 1026 if (G1->getSection() != G2->getSection()) 1027 return Error(ErrorMsg, 1028 "Appending variables with different section name need to be linked!"); 1029 1030 unsigned NewSize = T1->getNumElements() + T2->getNumElements(); 1031 ArrayType *NewType = ArrayType::get(T1->getElementType(), NewSize); 1032 1033 G1->setName(""); // Clear G1's name in case of a conflict! 1034 1035 // Create the new global variable... 1036 GlobalVariable *NG = 1037 new GlobalVariable(NewType, G1->isConstant(), G1->getLinkage(), 1038 /*init*/0, First->first, M, G1->isThreadLocal()); 1039 1040 // Propagate alignment, visibility and section info. 1041 CopyGVAttributes(NG, G1); 1042 1043 // Merge the initializer... 1044 Inits.reserve(NewSize); 1045 if (ConstantArray *I = dyn_cast<ConstantArray>(G1->getInitializer())) { 1046 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i) 1047 Inits.push_back(I->getOperand(i)); 1048 } else { 1049 assert(isa<ConstantAggregateZero>(G1->getInitializer())); 1050 Constant *CV = Constant::getNullValue(T1->getElementType()); 1051 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i) 1052 Inits.push_back(CV); 1053 } 1054 if (ConstantArray *I = dyn_cast<ConstantArray>(G2->getInitializer())) { 1055 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i) 1056 Inits.push_back(I->getOperand(i)); 1057 } else { 1058 assert(isa<ConstantAggregateZero>(G2->getInitializer())); 1059 Constant *CV = Constant::getNullValue(T2->getElementType()); 1060 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i) 1061 Inits.push_back(CV); 1062 } 1063 NG->setInitializer(ConstantArray::get(NewType, Inits)); 1064 Inits.clear(); 1065 1066 // Replace any uses of the two global variables with uses of the new 1067 // global... 1068 1069 // FIXME: This should rewrite simple/straight-forward uses such as 1070 // getelementptr instructions to not use the Cast! 1071 G1->replaceAllUsesWith(ConstantExpr::getBitCast(NG, G1->getType())); 1072 G2->replaceAllUsesWith(ConstantExpr::getBitCast(NG, G2->getType())); 1073 1074 // Remove the two globals from the module now... 1075 M->getGlobalList().erase(G1); 1076 M->getGlobalList().erase(G2); 1077 1078 // Put the new global into the AppendingVars map so that we can handle 1079 // linking of more than two vars... 1080 Second->second = NG; 1081 } 1082 AppendingVars.erase(First); 1083 } 1084 1085 return false; 1086} 1087 1088static bool ResolveAliases(Module *Dest) { 1089 for (Module::alias_iterator I = Dest->alias_begin(), E = Dest->alias_end(); 1090 I != E; ++I) 1091 if (const GlobalValue *GV = I->resolveAliasedGlobal()) 1092 if (!GV->isDeclaration()) 1093 I->replaceAllUsesWith(const_cast<GlobalValue*>(GV)); 1094 1095 return false; 1096} 1097 1098// LinkModules - This function links two modules together, with the resulting 1099// left module modified to be the composite of the two input modules. If an 1100// error occurs, true is returned and ErrorMsg (if not null) is set to indicate 1101// the problem. Upon failure, the Dest module could be in a modified state, and 1102// shouldn't be relied on to be consistent. 1103bool 1104Linker::LinkModules(Module *Dest, Module *Src, std::string *ErrorMsg) { 1105 assert(Dest != 0 && "Invalid Destination module"); 1106 assert(Src != 0 && "Invalid Source Module"); 1107 1108 if (Dest->getDataLayout().empty()) { 1109 if (!Src->getDataLayout().empty()) { 1110 Dest->setDataLayout(Src->getDataLayout()); 1111 } else { 1112 std::string DataLayout; 1113 1114 if (Dest->getEndianness() == Module::AnyEndianness) { 1115 if (Src->getEndianness() == Module::BigEndian) 1116 DataLayout.append("E"); 1117 else if (Src->getEndianness() == Module::LittleEndian) 1118 DataLayout.append("e"); 1119 } 1120 1121 if (Dest->getPointerSize() == Module::AnyPointerSize) { 1122 if (Src->getPointerSize() == Module::Pointer64) 1123 DataLayout.append(DataLayout.length() == 0 ? "p:64:64" : "-p:64:64"); 1124 else if (Src->getPointerSize() == Module::Pointer32) 1125 DataLayout.append(DataLayout.length() == 0 ? "p:32:32" : "-p:32:32"); 1126 } 1127 Dest->setDataLayout(DataLayout); 1128 } 1129 } 1130 1131 // Copy the target triple from the source to dest if the dest's is empty. 1132 if (Dest->getTargetTriple().empty() && !Src->getTargetTriple().empty()) 1133 Dest->setTargetTriple(Src->getTargetTriple()); 1134 1135 if (!Src->getDataLayout().empty() && !Dest->getDataLayout().empty() && 1136 Src->getDataLayout() != Dest->getDataLayout()) 1137 cerr << "WARNING: Linking two modules of different data layouts!\n"; 1138 if (!Src->getTargetTriple().empty() && 1139 Dest->getTargetTriple() != Src->getTargetTriple()) 1140 cerr << "WARNING: Linking two modules of different target triples!\n"; 1141 1142 // Append the module inline asm string. 1143 if (!Src->getModuleInlineAsm().empty()) { 1144 if (Dest->getModuleInlineAsm().empty()) 1145 Dest->setModuleInlineAsm(Src->getModuleInlineAsm()); 1146 else 1147 Dest->setModuleInlineAsm(Dest->getModuleInlineAsm()+"\n"+ 1148 Src->getModuleInlineAsm()); 1149 } 1150 1151 // Update the destination module's dependent libraries list with the libraries 1152 // from the source module. There's no opportunity for duplicates here as the 1153 // Module ensures that duplicate insertions are discarded. 1154 for (Module::lib_iterator SI = Src->lib_begin(), SE = Src->lib_end(); 1155 SI != SE; ++SI) 1156 Dest->addLibrary(*SI); 1157 1158 // LinkTypes - Go through the symbol table of the Src module and see if any 1159 // types are named in the src module that are not named in the Dst module. 1160 // Make sure there are no type name conflicts. 1161 if (LinkTypes(Dest, Src, ErrorMsg)) 1162 return true; 1163 1164 // ValueMap - Mapping of values from what they used to be in Src, to what they 1165 // are now in Dest. 1166 std::map<const Value*, Value*> ValueMap; 1167 1168 // AppendingVars - Keep track of global variables in the destination module 1169 // with appending linkage. After the module is linked together, they are 1170 // appended and the module is rewritten. 1171 std::multimap<std::string, GlobalVariable *> AppendingVars; 1172 for (Module::global_iterator I = Dest->global_begin(), E = Dest->global_end(); 1173 I != E; ++I) { 1174 // Add all of the appending globals already in the Dest module to 1175 // AppendingVars. 1176 if (I->hasAppendingLinkage()) 1177 AppendingVars.insert(std::make_pair(I->getName(), I)); 1178 } 1179 1180 // Insert all of the globals in src into the Dest module... without linking 1181 // initializers (which could refer to functions not yet mapped over). 1182 if (LinkGlobals(Dest, Src, ValueMap, AppendingVars, ErrorMsg)) 1183 return true; 1184 1185 // Link the functions together between the two modules, without doing function 1186 // bodies... this just adds external function prototypes to the Dest 1187 // function... We do this so that when we begin processing function bodies, 1188 // all of the global values that may be referenced are available in our 1189 // ValueMap. 1190 if (LinkFunctionProtos(Dest, Src, ValueMap, ErrorMsg)) 1191 return true; 1192 1193 // If there were any alias, link them now. We really need to do this now, 1194 // because all of the aliases that may be referenced need to be available in 1195 // ValueMap 1196 if (LinkAlias(Dest, Src, ValueMap, ErrorMsg)) return true; 1197 1198 // Update the initializers in the Dest module now that all globals that may 1199 // be referenced are in Dest. 1200 if (LinkGlobalInits(Dest, Src, ValueMap, ErrorMsg)) return true; 1201 1202 // Link in the function bodies that are defined in the source module into the 1203 // DestModule. This consists basically of copying the function over and 1204 // fixing up references to values. 1205 if (LinkFunctionBodies(Dest, Src, ValueMap, ErrorMsg)) return true; 1206 1207 // If there were any appending global variables, link them together now. 1208 if (LinkAppendingVars(Dest, AppendingVars, ErrorMsg)) return true; 1209 1210 // Resolve all uses of aliases with aliasees 1211 if (ResolveAliases(Dest)) return true; 1212 1213 // If the source library's module id is in the dependent library list of the 1214 // destination library, remove it since that module is now linked in. 1215 sys::Path modId; 1216 modId.set(Src->getModuleIdentifier()); 1217 if (!modId.isEmpty()) 1218 Dest->removeLibrary(modId.getBasename()); 1219 1220 return false; 1221} 1222 1223// vim: sw=2 1224