LinkModules.cpp revision c318329a1098a19137398af4d880f4d8cdd9cd8d
1//===- lib/Linker/LinkModules.cpp - Module Linker Implementation ----------===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file was developed by the LLVM research group and is distributed under 6// the University of Illinois Open Source License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file implements the LLVM module linker. 11// 12// Specifically, this: 13// * Merges global variables between the two modules 14// * Uninit + Uninit = Init, Init + Uninit = Init, Init + Init = Error if != 15// * Merges functions between two modules 16// 17//===----------------------------------------------------------------------===// 18 19#include "llvm/Linker.h" 20#include "llvm/Constants.h" 21#include "llvm/DerivedTypes.h" 22#include "llvm/Module.h" 23#include "llvm/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.insert(std::make_pair(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 } 362} 363 364/// GetLinkageResult - This analyzes the two global values and determines what 365/// the result will look like in the destination module. In particular, it 366/// computes the resultant linkage type, computes whether the global in the 367/// source should be copied over to the destination (replacing the existing 368/// one), and computes whether this linkage is an error or not. It also performs 369/// visibility checks: we cannot link together two symbols with different 370/// visibilities. 371static bool GetLinkageResult(GlobalValue *Dest, GlobalValue *Src, 372 GlobalValue::LinkageTypes <, bool &LinkFromSrc, 373 std::string *Err) { 374 assert((!Dest || !Src->hasInternalLinkage()) && 375 "If Src has internal linkage, Dest shouldn't be set!"); 376 if (!Dest) { 377 // Linking something to nothing. 378 LinkFromSrc = true; 379 LT = Src->getLinkage(); 380 } else if (Src->isDeclaration()) { 381 // If Src is external or if both Src & Drc are external.. Just link the 382 // external globals, we aren't adding anything. 383 if (Src->hasDLLImportLinkage()) { 384 // If one of GVs has DLLImport linkage, result should be dllimport'ed. 385 if (Dest->isDeclaration()) { 386 LinkFromSrc = true; 387 LT = Src->getLinkage(); 388 } 389 } else if (Dest->hasExternalWeakLinkage()) { 390 //If the Dest is weak, use the source linkage 391 LinkFromSrc = true; 392 LT = Src->getLinkage(); 393 } else { 394 LinkFromSrc = false; 395 LT = Dest->getLinkage(); 396 } 397 } else if (Dest->isDeclaration() && !Dest->hasDLLImportLinkage()) { 398 // If Dest is external but Src is not: 399 LinkFromSrc = true; 400 LT = Src->getLinkage(); 401 } else if (Src->hasAppendingLinkage() || Dest->hasAppendingLinkage()) { 402 if (Src->getLinkage() != Dest->getLinkage()) 403 return Error(Err, "Linking globals named '" + Src->getName() + 404 "': can only link appending global with another appending global!"); 405 LinkFromSrc = true; // Special cased. 406 LT = Src->getLinkage(); 407 } else if (Src->hasWeakLinkage() || Src->hasLinkOnceLinkage()) { 408 // At this point we know that Dest has LinkOnce, External*, Weak, or 409 // DLL* linkage. 410 if ((Dest->hasLinkOnceLinkage() && Src->hasWeakLinkage()) || 411 Dest->hasExternalWeakLinkage()) { 412 LinkFromSrc = true; 413 LT = Src->getLinkage(); 414 } else { 415 LinkFromSrc = false; 416 LT = Dest->getLinkage(); 417 } 418 } else if (Dest->hasWeakLinkage() || Dest->hasLinkOnceLinkage()) { 419 // At this point we know that Src has External* or DLL* linkage. 420 if (Src->hasExternalWeakLinkage()) { 421 LinkFromSrc = false; 422 LT = Dest->getLinkage(); 423 } else { 424 LinkFromSrc = true; 425 LT = GlobalValue::ExternalLinkage; 426 } 427 } else { 428 assert((Dest->hasExternalLinkage() || 429 Dest->hasDLLImportLinkage() || 430 Dest->hasDLLExportLinkage() || 431 Dest->hasExternalWeakLinkage()) && 432 (Src->hasExternalLinkage() || 433 Src->hasDLLImportLinkage() || 434 Src->hasDLLExportLinkage() || 435 Src->hasExternalWeakLinkage()) && 436 "Unexpected linkage type!"); 437 return Error(Err, "Linking globals named '" + Src->getName() + 438 "': symbol multiply defined!"); 439 } 440 441 // Check visibility 442 if (Dest && Src->getVisibility() != Dest->getVisibility()) 443 if (!Src->isDeclaration() && !Dest->isDeclaration()) 444 return Error(Err, "Linking globals named '" + Src->getName() + 445 "': symbols have different visibilities!"); 446 return false; 447} 448 449// LinkGlobals - Loop through the global variables in the src module and merge 450// them into the dest module. 451static bool LinkGlobals(Module *Dest, Module *Src, 452 std::map<const Value*, Value*> &ValueMap, 453 std::multimap<std::string, GlobalVariable *> &AppendingVars, 454 std::string *Err) { 455 // Loop over all of the globals in the src module, mapping them over as we go 456 for (Module::global_iterator I = Src->global_begin(), E = Src->global_end(); 457 I != E; ++I) { 458 GlobalVariable *SGV = I; 459 GlobalVariable *DGV = 0; 460 // Check to see if may have to link 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 if (DGV && DGV->hasInternalLinkage()) 470 DGV = 0; 471 472 assert((SGV->hasInitializer() || SGV->hasExternalWeakLinkage() || 473 SGV->hasExternalLinkage() || SGV->hasDLLImportLinkage()) && 474 "Global must either be external or have an initializer!"); 475 476 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; 477 bool LinkFromSrc = false; 478 if (GetLinkageResult(DGV, SGV, NewLinkage, LinkFromSrc, Err)) 479 return true; 480 481 if (!DGV) { 482 // No linking to be performed, simply create an identical version of the 483 // symbol over in the dest module... the initializer will be filled in 484 // later by LinkGlobalInits... 485 GlobalVariable *NewDGV = 486 new GlobalVariable(SGV->getType()->getElementType(), 487 SGV->isConstant(), SGV->getLinkage(), /*init*/0, 488 SGV->getName(), Dest, SGV->isThreadLocal()); 489 // Propagate alignment, visibility and section info. 490 CopyGVAttributes(NewDGV, SGV); 491 492 // If the LLVM runtime renamed the global, but it is an externally visible 493 // symbol, DGV must be an existing global with internal linkage. Rename 494 // it. 495 if (NewDGV->getName() != SGV->getName() && !NewDGV->hasInternalLinkage()) 496 ForceRenaming(NewDGV, SGV->getName()); 497 498 // Make sure to remember this mapping... 499 ValueMap.insert(std::make_pair(SGV, NewDGV)); 500 if (SGV->hasAppendingLinkage()) 501 // Keep track that this is an appending variable... 502 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV)); 503 } else if (DGV->hasAppendingLinkage()) { 504 // No linking is performed yet. Just insert a new copy of the global, and 505 // keep track of the fact that it is an appending variable in the 506 // AppendingVars map. The name is cleared out so that no linkage is 507 // performed. 508 GlobalVariable *NewDGV = 509 new GlobalVariable(SGV->getType()->getElementType(), 510 SGV->isConstant(), SGV->getLinkage(), /*init*/0, 511 "", Dest, SGV->isThreadLocal()); 512 513 // Propagate alignment, section and visibility info. 514 NewDGV->setAlignment(DGV->getAlignment()); 515 CopyGVAttributes(NewDGV, SGV); 516 517 // Make sure to remember this mapping... 518 ValueMap.insert(std::make_pair(SGV, NewDGV)); 519 520 // Keep track that this is an appending variable... 521 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV)); 522 } else { 523 // Propagate alignment, section, and visibility info. 524 CopyGVAttributes(DGV, SGV); 525 526 // Otherwise, perform the mapping as instructed by GetLinkageResult. If 527 // the types don't match, and if we are to link from the source, nuke DGV 528 // and create a new one of the appropriate type. 529 if (SGV->getType() != DGV->getType() && LinkFromSrc) { 530 GlobalVariable *NewDGV = 531 new GlobalVariable(SGV->getType()->getElementType(), 532 DGV->isConstant(), DGV->getLinkage()); 533 NewDGV->setThreadLocal(DGV->isThreadLocal()); 534 CopyGVAttributes(NewDGV, DGV); 535 Dest->getGlobalList().insert(DGV, NewDGV); 536 DGV->replaceAllUsesWith( 537 ConstantExpr::getBitCast(NewDGV, DGV->getType())); 538 DGV->eraseFromParent(); 539 NewDGV->setName(SGV->getName()); 540 DGV = NewDGV; 541 } 542 543 DGV->setLinkage(NewLinkage); 544 545 if (LinkFromSrc) { 546 // Inherit const as appropriate 547 DGV->setConstant(SGV->isConstant()); 548 DGV->setInitializer(0); 549 } else { 550 if (SGV->isConstant() && !DGV->isConstant()) { 551 if (DGV->isDeclaration()) 552 DGV->setConstant(true); 553 } 554 SGV->setLinkage(GlobalValue::ExternalLinkage); 555 SGV->setInitializer(0); 556 } 557 558 ValueMap.insert( 559 std::make_pair(SGV, ConstantExpr::getBitCast(DGV, SGV->getType()))); 560 } 561 } 562 return false; 563} 564 565// LinkAlias - Loop through the alias in the src module and link them into the 566// dest module. 567static bool LinkAlias(Module *Dest, const Module *Src, std::string *Err) { 568 // Loop over all alias in the src module 569 for (Module::const_alias_iterator I = Src->alias_begin(), 570 E = Src->alias_end(); I != E; ++I) { 571 const GlobalAlias *GA = I; 572 573 GlobalValue *NewAliased = NULL; 574 const GlobalValue *Aliased = GA->getAliasedGlobal(); 575 if (isa<GlobalVariable>(*Aliased)) 576 NewAliased = Dest->getGlobalVariable(Aliased->getName()); 577 else if (isa<Function>(*Aliased)) 578 NewAliased = Dest->getFunction(Aliased->getName()); 579 // FIXME: we should handle the bitcast alias. 580 assert(NewAliased && "Can't find the aliased GV."); 581 582 GlobalAlias *NewGA = new GlobalAlias(GA->getType(), GA->getLinkage(), 583 GA->getName(), NewAliased, Dest); 584 CopyGVAttributes(NewGA, GA); 585 } 586 return false; 587} 588 589 590// LinkGlobalInits - Update the initializers in the Dest module now that all 591// globals that may be referenced are in Dest. 592static bool LinkGlobalInits(Module *Dest, const Module *Src, 593 std::map<const Value*, Value*> &ValueMap, 594 std::string *Err) { 595 596 // Loop over all of the globals in the src module, mapping them over as we go 597 for (Module::const_global_iterator I = Src->global_begin(), 598 E = Src->global_end(); I != E; ++I) { 599 const GlobalVariable *SGV = I; 600 601 if (SGV->hasInitializer()) { // Only process initialized GV's 602 // Figure out what the initializer looks like in the dest module... 603 Constant *SInit = 604 cast<Constant>(RemapOperand(SGV->getInitializer(), ValueMap)); 605 606 GlobalVariable *DGV = cast<GlobalVariable>(ValueMap[SGV]); 607 if (DGV->hasInitializer()) { 608 if (SGV->hasExternalLinkage()) { 609 if (DGV->getInitializer() != SInit) 610 return Error(Err, "Global Variable Collision on '" + 611 ToStr(SGV->getType(), Src) +"':%"+SGV->getName()+ 612 " - Global variables have different initializers"); 613 } else if (DGV->hasLinkOnceLinkage() || DGV->hasWeakLinkage()) { 614 // Nothing is required, mapped values will take the new global 615 // automatically. 616 } else if (SGV->hasLinkOnceLinkage() || SGV->hasWeakLinkage()) { 617 // Nothing is required, mapped values will take the new global 618 // automatically. 619 } else if (DGV->hasAppendingLinkage()) { 620 assert(0 && "Appending linkage unimplemented!"); 621 } else { 622 assert(0 && "Unknown linkage!"); 623 } 624 } else { 625 // Copy the initializer over now... 626 DGV->setInitializer(SInit); 627 } 628 } 629 } 630 return false; 631} 632 633// LinkFunctionProtos - Link the functions together between the two modules, 634// without doing function bodies... this just adds external function prototypes 635// to the Dest function... 636// 637static bool LinkFunctionProtos(Module *Dest, const Module *Src, 638 std::map<const Value*, Value*> &ValueMap, 639 std::string *Err) { 640 // Loop over all of the functions in the src module, mapping them over 641 for (Module::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) { 642 const Function *SF = I; // SrcFunction 643 Function *DF = 0; 644 if (SF->hasName() && !SF->hasInternalLinkage()) { 645 // Check to see if may have to link the function. 646 DF = Dest->getFunction(SF->getName()); 647 if (DF && SF->getType() != DF->getType()) 648 // If types don't agree because of opaque, try to resolve them 649 RecursiveResolveTypes(SF->getType(), DF->getType(), 650 &Dest->getTypeSymbolTable(), ""); 651 } 652 653 // Check visibility 654 if (DF && !DF->hasInternalLinkage() && 655 SF->getVisibility() != DF->getVisibility()) { 656 // If one is a prototype, ignore its visibility. Prototypes are always 657 // overridden by the definition. 658 if (!SF->isDeclaration() && !DF->isDeclaration()) 659 return Error(Err, "Linking functions named '" + SF->getName() + 660 "': symbols have different visibilities!"); 661 } 662 663 if (DF && DF->getType() != SF->getType()) { 664 if (DF->isDeclaration() && !SF->isDeclaration()) { 665 // We have a definition of the same name but different type in the 666 // source module. Copy the prototype to the destination and replace 667 // uses of the destination's prototype with the new prototype. 668 Function *NewDF = new Function(SF->getFunctionType(), SF->getLinkage(), 669 SF->getName(), Dest); 670 CopyGVAttributes(NewDF, SF); 671 672 // Any uses of DF need to change to NewDF, with cast 673 DF->replaceAllUsesWith(ConstantExpr::getBitCast(NewDF, DF->getType())); 674 675 // DF will conflict with NewDF because they both had the same. We must 676 // erase this now so ForceRenaming doesn't assert because DF might 677 // not have internal linkage. 678 DF->eraseFromParent(); 679 680 // If the symbol table renamed the function, but it is an externally 681 // visible symbol, DF must be an existing function with internal 682 // linkage. Rename it. 683 if (NewDF->getName() != SF->getName() && !NewDF->hasInternalLinkage()) 684 ForceRenaming(NewDF, SF->getName()); 685 686 // Remember this mapping so uses in the source module get remapped 687 // later by RemapOperand. 688 ValueMap[SF] = NewDF; 689 } else if (SF->isDeclaration()) { 690 // We have two functions of the same name but different type and the 691 // source is a declaration while the destination is not. Any use of 692 // the source must be mapped to the destination, with a cast. 693 ValueMap[SF] = ConstantExpr::getBitCast(DF, SF->getType()); 694 } else { 695 // We have two functions of the same name but different types and they 696 // are both definitions. This is an error. 697 return Error(Err, "Function '" + DF->getName() + "' defined as both '" + 698 ToStr(SF->getFunctionType(), Src) + "' and '" + 699 ToStr(DF->getFunctionType(), Dest) + "'"); 700 } 701 } else if (!DF || SF->hasInternalLinkage() || DF->hasInternalLinkage()) { 702 // Function does not already exist, simply insert an function signature 703 // identical to SF into the dest module. 704 Function *NewDF = new Function(SF->getFunctionType(), SF->getLinkage(), 705 SF->getName(), Dest); 706 CopyGVAttributes(NewDF, SF); 707 708 // If the LLVM runtime renamed the function, but it is an externally 709 // visible symbol, DF must be an existing function with internal linkage. 710 // Rename it. 711 if (NewDF->getName() != SF->getName() && !NewDF->hasInternalLinkage()) 712 ForceRenaming(NewDF, SF->getName()); 713 714 // ... and remember this mapping... 715 ValueMap.insert(std::make_pair(SF, NewDF)); 716 } else if (SF->isDeclaration()) { 717 // If SF is a declaration or if both SF & DF are declarations, just link 718 // the declarations, we aren't adding anything. 719 if (SF->hasDLLImportLinkage()) { 720 if (DF->isDeclaration()) { 721 ValueMap.insert(std::make_pair(SF, DF)); 722 DF->setLinkage(SF->getLinkage()); 723 } 724 } else { 725 ValueMap.insert(std::make_pair(SF, DF)); 726 } 727 } else if (DF->isDeclaration() && !DF->hasDLLImportLinkage()) { 728 // If DF is external but SF is not... 729 // Link the external functions, update linkage qualifiers 730 ValueMap.insert(std::make_pair(SF, DF)); 731 DF->setLinkage(SF->getLinkage()); 732 // Visibility of prototype is overridden by vis of definition. 733 DF->setVisibility(SF->getVisibility()); 734 } else if (SF->hasWeakLinkage() || SF->hasLinkOnceLinkage()) { 735 // At this point we know that DF has LinkOnce, Weak, or External* linkage. 736 ValueMap.insert(std::make_pair(SF, DF)); 737 738 // Linkonce+Weak = Weak 739 // *+External Weak = * 740 if ((DF->hasLinkOnceLinkage() && SF->hasWeakLinkage()) || 741 DF->hasExternalWeakLinkage()) 742 DF->setLinkage(SF->getLinkage()); 743 } else if (DF->hasWeakLinkage() || DF->hasLinkOnceLinkage()) { 744 // At this point we know that SF has LinkOnce or External* linkage. 745 ValueMap.insert(std::make_pair(SF, DF)); 746 if (!SF->hasLinkOnceLinkage() && !SF->hasExternalWeakLinkage()) 747 // Don't inherit linkonce & external weak linkage 748 DF->setLinkage(SF->getLinkage()); 749 } else if (SF->getLinkage() != DF->getLinkage()) { 750 return Error(Err, "Functions named '" + SF->getName() + 751 "' have different linkage specifiers!"); 752 } else if (SF->hasExternalLinkage()) { 753 // The function is defined identically in both modules!! 754 return Error(Err, "Function '" + 755 ToStr(SF->getFunctionType(), Src) + "':\"" + 756 SF->getName() + "\" - Function is already defined!"); 757 } else { 758 assert(0 && "Unknown linkage configuration found!"); 759 } 760 } 761 return false; 762} 763 764// LinkFunctionBody - Copy the source function over into the dest function and 765// fix up references to values. At this point we know that Dest is an external 766// function, and that Src is not. 767static bool LinkFunctionBody(Function *Dest, Function *Src, 768 std::map<const Value*, Value*> &ValueMap, 769 std::string *Err) { 770 assert(Src && Dest && Dest->isDeclaration() && !Src->isDeclaration()); 771 772 // Go through and convert function arguments over, remembering the mapping. 773 Function::arg_iterator DI = Dest->arg_begin(); 774 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end(); 775 I != E; ++I, ++DI) { 776 DI->setName(I->getName()); // Copy the name information over... 777 778 // Add a mapping to our local map 779 ValueMap.insert(std::make_pair(I, DI)); 780 } 781 782 // Splice the body of the source function into the dest function. 783 Dest->getBasicBlockList().splice(Dest->end(), Src->getBasicBlockList()); 784 785 // At this point, all of the instructions and values of the function are now 786 // copied over. The only problem is that they are still referencing values in 787 // the Source function as operands. Loop through all of the operands of the 788 // functions and patch them up to point to the local versions... 789 // 790 for (Function::iterator BB = Dest->begin(), BE = Dest->end(); BB != BE; ++BB) 791 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) 792 for (Instruction::op_iterator OI = I->op_begin(), OE = I->op_end(); 793 OI != OE; ++OI) 794 if (!isa<Instruction>(*OI) && !isa<BasicBlock>(*OI)) 795 *OI = RemapOperand(*OI, ValueMap); 796 797 // There is no need to map the arguments anymore. 798 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end(); 799 I != E; ++I) 800 ValueMap.erase(I); 801 802 return false; 803} 804 805 806// LinkFunctionBodies - Link in the function bodies that are defined in the 807// source module into the DestModule. This consists basically of copying the 808// function over and fixing up references to values. 809static bool LinkFunctionBodies(Module *Dest, Module *Src, 810 std::map<const Value*, Value*> &ValueMap, 811 std::string *Err) { 812 813 // Loop over all of the functions in the src module, mapping them over as we 814 // go 815 for (Module::iterator SF = Src->begin(), E = Src->end(); SF != E; ++SF) { 816 if (!SF->isDeclaration()) { // No body if function is external 817 Function *DF = cast<Function>(ValueMap[SF]); // Destination function 818 819 // DF not external SF external? 820 if (DF->isDeclaration()) 821 // Only provide the function body if there isn't one already. 822 if (LinkFunctionBody(DF, SF, ValueMap, Err)) 823 return true; 824 } 825 } 826 return false; 827} 828 829// LinkAppendingVars - If there were any appending global variables, link them 830// together now. Return true on error. 831static bool LinkAppendingVars(Module *M, 832 std::multimap<std::string, GlobalVariable *> &AppendingVars, 833 std::string *ErrorMsg) { 834 if (AppendingVars.empty()) return false; // Nothing to do. 835 836 // Loop over the multimap of appending vars, processing any variables with the 837 // same name, forming a new appending global variable with both of the 838 // initializers merged together, then rewrite references to the old variables 839 // and delete them. 840 std::vector<Constant*> Inits; 841 while (AppendingVars.size() > 1) { 842 // Get the first two elements in the map... 843 std::multimap<std::string, 844 GlobalVariable*>::iterator Second = AppendingVars.begin(), First=Second++; 845 846 // If the first two elements are for different names, there is no pair... 847 // Otherwise there is a pair, so link them together... 848 if (First->first == Second->first) { 849 GlobalVariable *G1 = First->second, *G2 = Second->second; 850 const ArrayType *T1 = cast<ArrayType>(G1->getType()->getElementType()); 851 const ArrayType *T2 = cast<ArrayType>(G2->getType()->getElementType()); 852 853 // Check to see that they two arrays agree on type... 854 if (T1->getElementType() != T2->getElementType()) 855 return Error(ErrorMsg, 856 "Appending variables with different element types need to be linked!"); 857 if (G1->isConstant() != G2->isConstant()) 858 return Error(ErrorMsg, 859 "Appending variables linked with different const'ness!"); 860 861 if (G1->getAlignment() != G2->getAlignment()) 862 return Error(ErrorMsg, 863 "Appending variables with different alignment need to be linked!"); 864 865 if (G1->getVisibility() != G2->getVisibility()) 866 return Error(ErrorMsg, 867 "Appending variables with different visibility need to be linked!"); 868 869 if (G1->getSection() != G2->getSection()) 870 return Error(ErrorMsg, 871 "Appending variables with different section name need to be linked!"); 872 873 unsigned NewSize = T1->getNumElements() + T2->getNumElements(); 874 ArrayType *NewType = ArrayType::get(T1->getElementType(), NewSize); 875 876 G1->setName(""); // Clear G1's name in case of a conflict! 877 878 // Create the new global variable... 879 GlobalVariable *NG = 880 new GlobalVariable(NewType, G1->isConstant(), G1->getLinkage(), 881 /*init*/0, First->first, M, G1->isThreadLocal()); 882 883 // Propagate alignment, visibility and section info. 884 CopyGVAttributes(NG, G1); 885 886 // Merge the initializer... 887 Inits.reserve(NewSize); 888 if (ConstantArray *I = dyn_cast<ConstantArray>(G1->getInitializer())) { 889 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i) 890 Inits.push_back(I->getOperand(i)); 891 } else { 892 assert(isa<ConstantAggregateZero>(G1->getInitializer())); 893 Constant *CV = Constant::getNullValue(T1->getElementType()); 894 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i) 895 Inits.push_back(CV); 896 } 897 if (ConstantArray *I = dyn_cast<ConstantArray>(G2->getInitializer())) { 898 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i) 899 Inits.push_back(I->getOperand(i)); 900 } else { 901 assert(isa<ConstantAggregateZero>(G2->getInitializer())); 902 Constant *CV = Constant::getNullValue(T2->getElementType()); 903 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i) 904 Inits.push_back(CV); 905 } 906 NG->setInitializer(ConstantArray::get(NewType, Inits)); 907 Inits.clear(); 908 909 // Replace any uses of the two global variables with uses of the new 910 // global... 911 912 // FIXME: This should rewrite simple/straight-forward uses such as 913 // getelementptr instructions to not use the Cast! 914 G1->replaceAllUsesWith(ConstantExpr::getBitCast(NG, G1->getType())); 915 G2->replaceAllUsesWith(ConstantExpr::getBitCast(NG, G2->getType())); 916 917 // Remove the two globals from the module now... 918 M->getGlobalList().erase(G1); 919 M->getGlobalList().erase(G2); 920 921 // Put the new global into the AppendingVars map so that we can handle 922 // linking of more than two vars... 923 Second->second = NG; 924 } 925 AppendingVars.erase(First); 926 } 927 928 return false; 929} 930 931 932// LinkModules - This function links two modules together, with the resulting 933// left module modified to be the composite of the two input modules. If an 934// error occurs, true is returned and ErrorMsg (if not null) is set to indicate 935// the problem. Upon failure, the Dest module could be in a modified state, and 936// shouldn't be relied on to be consistent. 937bool 938Linker::LinkModules(Module *Dest, Module *Src, std::string *ErrorMsg) { 939 assert(Dest != 0 && "Invalid Destination module"); 940 assert(Src != 0 && "Invalid Source Module"); 941 942 if (Dest->getDataLayout().empty()) { 943 if (!Src->getDataLayout().empty()) { 944 Dest->setDataLayout(Src->getDataLayout()); 945 } else { 946 std::string DataLayout; 947 948 if (Dest->getEndianness() == Module::AnyEndianness) 949 if (Src->getEndianness() == Module::BigEndian) 950 DataLayout.append("E"); 951 else if (Src->getEndianness() == Module::LittleEndian) 952 DataLayout.append("e"); 953 if (Dest->getPointerSize() == Module::AnyPointerSize) 954 if (Src->getPointerSize() == Module::Pointer64) 955 DataLayout.append(DataLayout.length() == 0 ? "p:64:64" : "-p:64:64"); 956 else if (Src->getPointerSize() == Module::Pointer32) 957 DataLayout.append(DataLayout.length() == 0 ? "p:32:32" : "-p:32:32"); 958 Dest->setDataLayout(DataLayout); 959 } 960 } 961 962 // COpy the target triple from the source to dest if the dest's is empty 963 if (Dest->getTargetTriple().empty() && !Src->getTargetTriple().empty()) 964 Dest->setTargetTriple(Src->getTargetTriple()); 965 966 if (!Src->getDataLayout().empty() && !Dest->getDataLayout().empty() && 967 Src->getDataLayout() != Dest->getDataLayout()) 968 cerr << "WARNING: Linking two modules of different data layouts!\n"; 969 if (!Src->getTargetTriple().empty() && 970 Dest->getTargetTriple() != Src->getTargetTriple()) 971 cerr << "WARNING: Linking two modules of different target triples!\n"; 972 973 // Append the module inline asm string 974 if (!Src->getModuleInlineAsm().empty()) { 975 if (Dest->getModuleInlineAsm().empty()) 976 Dest->setModuleInlineAsm(Src->getModuleInlineAsm()); 977 else 978 Dest->setModuleInlineAsm(Dest->getModuleInlineAsm()+"\n"+ 979 Src->getModuleInlineAsm()); 980 } 981 982 // Update the destination module's dependent libraries list with the libraries 983 // from the source module. There's no opportunity for duplicates here as the 984 // Module ensures that duplicate insertions are discarded. 985 Module::lib_iterator SI = Src->lib_begin(); 986 Module::lib_iterator SE = Src->lib_end(); 987 while ( SI != SE ) { 988 Dest->addLibrary(*SI); 989 ++SI; 990 } 991 992 // LinkTypes - Go through the symbol table of the Src module and see if any 993 // types are named in the src module that are not named in the Dst module. 994 // Make sure there are no type name conflicts. 995 if (LinkTypes(Dest, Src, ErrorMsg)) 996 return true; 997 998 // ValueMap - Mapping of values from what they used to be in Src, to what they 999 // are now in Dest. 1000 std::map<const Value*, Value*> ValueMap; 1001 1002 // AppendingVars - Keep track of global variables in the destination module 1003 // with appending linkage. After the module is linked together, they are 1004 // appended and the module is rewritten. 1005 std::multimap<std::string, GlobalVariable *> AppendingVars; 1006 for (Module::global_iterator I = Dest->global_begin(), E = Dest->global_end(); 1007 I != E; ++I) { 1008 // Add all of the appending globals already in the Dest module to 1009 // AppendingVars. 1010 if (I->hasAppendingLinkage()) 1011 AppendingVars.insert(std::make_pair(I->getName(), I)); 1012 } 1013 1014 // Insert all of the globals in src into the Dest module... without linking 1015 // initializers (which could refer to functions not yet mapped over). 1016 if (LinkGlobals(Dest, Src, ValueMap, AppendingVars, ErrorMsg)) 1017 return true; 1018 1019 // Link the functions together between the two modules, without doing function 1020 // bodies... this just adds external function prototypes to the Dest 1021 // function... We do this so that when we begin processing function bodies, 1022 // all of the global values that may be referenced are available in our 1023 // ValueMap. 1024 if (LinkFunctionProtos(Dest, Src, ValueMap, ErrorMsg)) 1025 return true; 1026 1027 // Update the initializers in the Dest module now that all globals that may 1028 // be referenced are in Dest. 1029 if (LinkGlobalInits(Dest, Src, ValueMap, ErrorMsg)) return true; 1030 1031 // Link in the function bodies that are defined in the source module into the 1032 // DestModule. This consists basically of copying the function over and 1033 // fixing up references to values. 1034 if (LinkFunctionBodies(Dest, Src, ValueMap, ErrorMsg)) return true; 1035 1036 // If there were any appending global variables, link them together now. 1037 if (LinkAppendingVars(Dest, AppendingVars, ErrorMsg)) return true; 1038 1039 // If there were any alias, link them now. 1040 if (LinkAlias(Dest, Src, ErrorMsg)) return true; 1041 1042 // If the source library's module id is in the dependent library list of the 1043 // destination library, remove it since that module is now linked in. 1044 sys::Path modId; 1045 modId.set(Src->getModuleIdentifier()); 1046 if (!modId.isEmpty()) 1047 Dest->removeLibrary(modId.getBasename()); 1048 1049 return false; 1050} 1051 1052// vim: sw=2 1053