LinkModules.cpp revision ef9b9a793949469cdaa4ab6d0173136229dcab7b
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 ConstantPacked *CP = dyn_cast<ConstantPacked>(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 = ConstantPacked::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 GlobalValue *ConflictGV = cast_or_null<GlobalValue>(ST.lookup(Name)); 341 if (ConflictGV) { 342 assert(ConflictGV->hasInternalLinkage() && 343 "Not conflicting with a static global, should link instead!"); 344 ConflictGV->setName(""); // Eliminate the conflict 345 } 346 GV->setName(Name); // Force the name back 347 if (ConflictGV) { 348 ConflictGV->setName(Name); // This will cause ConflictGV to get renamed 349 assert(ConflictGV->getName() != Name && "ForceRenaming didn't work"); 350 } 351 assert(GV->getName() == Name && "ForceRenaming didn't work"); 352} 353 354/// CopyGVAttributes - copy additional attributes (those not needed to construct 355/// a GlobalValue) from the SrcGV to the DestGV. 356static void CopyGVAttributes(GlobalValue *DestGV, const GlobalValue *SrcGV) { 357 // Propagate alignment, visibility and section info. 358 DestGV->setAlignment(std::max(DestGV->getAlignment(), SrcGV->getAlignment())); 359 DestGV->setSection(SrcGV->getSection()); 360 DestGV->setVisibility(SrcGV->getVisibility()); 361 if (const Function *SrcF = dyn_cast<Function>(SrcGV)) { 362 Function *DestF = cast<Function>(DestGV); 363 DestF->setCallingConv(SrcF->getCallingConv()); 364 } 365} 366 367/// GetLinkageResult - This analyzes the two global values and determines what 368/// the result will look like in the destination module. In particular, it 369/// computes the resultant linkage type, computes whether the global in the 370/// source should be copied over to the destination (replacing the existing 371/// one), and computes whether this linkage is an error or not. 372static bool GetLinkageResult(GlobalValue *Dest, GlobalValue *Src, 373 GlobalValue::LinkageTypes <, bool &LinkFromSrc, 374 std::string *Err) { 375 assert((!Dest || !Src->hasInternalLinkage()) && 376 "If Src has internal linkage, Dest shouldn't be set!"); 377 if (!Dest) { 378 // Linking something to nothing. 379 LinkFromSrc = true; 380 LT = Src->getLinkage(); 381 } else if (Src->isDeclaration()) { 382 // If Src is external or if both Src & Drc are external.. Just link the 383 // external globals, we aren't adding anything. 384 if (Src->hasDLLImportLinkage()) { 385 // If one of GVs has DLLImport linkage, result should be dllimport'ed. 386 if (Dest->isDeclaration()) { 387 LinkFromSrc = true; 388 LT = Src->getLinkage(); 389 } 390 } else if (Dest->hasExternalWeakLinkage()) { 391 //If the Dest is weak, use the source linkage 392 LinkFromSrc = true; 393 LT = Src->getLinkage(); 394 } else { 395 LinkFromSrc = false; 396 LT = Dest->getLinkage(); 397 } 398 } else if (Dest->isDeclaration() && !Dest->hasDLLImportLinkage()) { 399 // If Dest is external but Src is not: 400 LinkFromSrc = true; 401 LT = Src->getLinkage(); 402 } else if (Src->hasAppendingLinkage() || Dest->hasAppendingLinkage()) { 403 if (Src->getLinkage() != Dest->getLinkage()) 404 return Error(Err, "Linking globals named '" + Src->getName() + 405 "': can only link appending global with another appending global!"); 406 LinkFromSrc = true; // Special cased. 407 LT = Src->getLinkage(); 408 } else if (Src->hasWeakLinkage() || Src->hasLinkOnceLinkage()) { 409 // At this point we know that Dest has LinkOnce, External*, Weak, or 410 // DLL* linkage. 411 if ((Dest->hasLinkOnceLinkage() && Src->hasWeakLinkage()) || 412 Dest->hasExternalWeakLinkage()) { 413 LinkFromSrc = true; 414 LT = Src->getLinkage(); 415 } else { 416 LinkFromSrc = false; 417 LT = Dest->getLinkage(); 418 } 419 } else if (Dest->hasWeakLinkage() || Dest->hasLinkOnceLinkage()) { 420 // At this point we know that Src has External* or DLL* linkage. 421 if (Src->hasExternalWeakLinkage()) { 422 LinkFromSrc = false; 423 LT = Dest->getLinkage(); 424 } else { 425 LinkFromSrc = true; 426 LT = GlobalValue::ExternalLinkage; 427 } 428 } else { 429 assert((Dest->hasExternalLinkage() || 430 Dest->hasDLLImportLinkage() || 431 Dest->hasDLLExportLinkage() || 432 Dest->hasExternalWeakLinkage()) && 433 (Src->hasExternalLinkage() || 434 Src->hasDLLImportLinkage() || 435 Src->hasDLLExportLinkage() || 436 Src->hasExternalWeakLinkage()) && 437 "Unexpected linkage type!"); 438 return Error(Err, "Linking globals named '" + Src->getName() + 439 "': symbol multiply defined!"); 440 } 441 return false; 442} 443 444// LinkGlobals - Loop through the global variables in the src module and merge 445// them into the dest module. 446static bool LinkGlobals(Module *Dest, Module *Src, 447 std::map<const Value*, Value*> &ValueMap, 448 std::multimap<std::string, GlobalVariable *> &AppendingVars, 449 std::string *Err) { 450 // Loop over all of the globals in the src module, mapping them over as we go 451 for (Module::global_iterator I = Src->global_begin(), E = Src->global_end(); 452 I != E; ++I) { 453 GlobalVariable *SGV = I; 454 GlobalVariable *DGV = 0; 455 // Check to see if may have to link the global. 456 if (SGV->hasName() && !SGV->hasInternalLinkage()) { 457 DGV = Dest->getGlobalVariable(SGV->getName()); 458 if (DGV && DGV->getType() != SGV->getType()) 459 // If types don't agree due to opaque types, try to resolve them. 460 RecursiveResolveTypes(SGV->getType(), DGV->getType(), 461 &Dest->getTypeSymbolTable(), ""); 462 } 463 464 if (DGV && DGV->hasInternalLinkage()) 465 DGV = 0; 466 467 assert(SGV->hasInitializer() || SGV->hasExternalWeakLinkage() || 468 SGV->hasExternalLinkage() || SGV->hasDLLImportLinkage() && 469 "Global must either be external or have an initializer!"); 470 471 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; 472 bool LinkFromSrc = false; 473 if (GetLinkageResult(DGV, SGV, NewLinkage, LinkFromSrc, Err)) 474 return true; 475 476 if (!DGV) { 477 // No linking to be performed, simply create an identical version of the 478 // symbol over in the dest module... the initializer will be filled in 479 // later by LinkGlobalInits... 480 GlobalVariable *NewDGV = 481 new GlobalVariable(SGV->getType()->getElementType(), 482 SGV->isConstant(), SGV->getLinkage(), /*init*/0, 483 SGV->getName(), Dest); 484 // Propagate alignment, visibility and section info. 485 CopyGVAttributes(NewDGV, SGV); 486 487 // If the LLVM runtime renamed the global, but it is an externally visible 488 // symbol, DGV must be an existing global with internal linkage. Rename 489 // it. 490 if (NewDGV->getName() != SGV->getName() && !NewDGV->hasInternalLinkage()) 491 ForceRenaming(NewDGV, SGV->getName()); 492 493 // Make sure to remember this mapping... 494 ValueMap.insert(std::make_pair(SGV, NewDGV)); 495 if (SGV->hasAppendingLinkage()) 496 // Keep track that this is an appending variable... 497 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV)); 498 } else if (DGV->hasAppendingLinkage()) { 499 // No linking is performed yet. Just insert a new copy of the global, and 500 // keep track of the fact that it is an appending variable in the 501 // AppendingVars map. The name is cleared out so that no linkage is 502 // performed. 503 GlobalVariable *NewDGV = 504 new GlobalVariable(SGV->getType()->getElementType(), 505 SGV->isConstant(), SGV->getLinkage(), /*init*/0, 506 "", Dest); 507 508 // Propagate alignment, section and visibility info. 509 NewDGV->setAlignment(DGV->getAlignment()); 510 CopyGVAttributes(NewDGV, SGV); 511 512 // Make sure to remember this mapping... 513 ValueMap.insert(std::make_pair(SGV, NewDGV)); 514 515 // Keep track that this is an appending variable... 516 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV)); 517 } else { 518 // Propagate alignment, section, and visibility info. 519 CopyGVAttributes(DGV, SGV); 520 521 // Otherwise, perform the mapping as instructed by GetLinkageResult. If 522 // the types don't match, and if we are to link from the source, nuke DGV 523 // and create a new one of the appropriate type. 524 if (SGV->getType() != DGV->getType() && LinkFromSrc) { 525 GlobalVariable *NewDGV = 526 new GlobalVariable(SGV->getType()->getElementType(), 527 DGV->isConstant(), DGV->getLinkage()); 528 CopyGVAttributes(NewDGV, DGV); 529 Dest->getGlobalList().insert(DGV, NewDGV); 530 DGV->replaceAllUsesWith( 531 ConstantExpr::getBitCast(NewDGV, DGV->getType())); 532 DGV->eraseFromParent(); 533 NewDGV->setName(SGV->getName()); 534 DGV = NewDGV; 535 } 536 537 DGV->setLinkage(NewLinkage); 538 539 if (LinkFromSrc) { 540 // Inherit const as appropriate 541 DGV->setConstant(SGV->isConstant()); 542 DGV->setInitializer(0); 543 } else { 544 if (SGV->isConstant() && !DGV->isConstant()) { 545 if (DGV->isDeclaration()) 546 DGV->setConstant(true); 547 } 548 SGV->setLinkage(GlobalValue::ExternalLinkage); 549 SGV->setInitializer(0); 550 } 551 552 ValueMap.insert( 553 std::make_pair(SGV, ConstantExpr::getBitCast(DGV, SGV->getType()))); 554 } 555 } 556 return false; 557} 558 559 560// LinkGlobalInits - Update the initializers in the Dest module now that all 561// globals that may be referenced are in Dest. 562static bool LinkGlobalInits(Module *Dest, const Module *Src, 563 std::map<const Value*, Value*> &ValueMap, 564 std::string *Err) { 565 566 // Loop over all of the globals in the src module, mapping them over as we go 567 for (Module::const_global_iterator I = Src->global_begin(), 568 E = Src->global_end(); I != E; ++I) { 569 const GlobalVariable *SGV = I; 570 571 if (SGV->hasInitializer()) { // Only process initialized GV's 572 // Figure out what the initializer looks like in the dest module... 573 Constant *SInit = 574 cast<Constant>(RemapOperand(SGV->getInitializer(), ValueMap)); 575 576 GlobalVariable *DGV = cast<GlobalVariable>(ValueMap[SGV]); 577 if (DGV->hasInitializer()) { 578 if (SGV->hasExternalLinkage()) { 579 if (DGV->getInitializer() != SInit) 580 return Error(Err, "Global Variable Collision on '" + 581 ToStr(SGV->getType(), Src) +"':%"+SGV->getName()+ 582 " - Global variables have different initializers"); 583 } else if (DGV->hasLinkOnceLinkage() || DGV->hasWeakLinkage()) { 584 // Nothing is required, mapped values will take the new global 585 // automatically. 586 } else if (SGV->hasLinkOnceLinkage() || SGV->hasWeakLinkage()) { 587 // Nothing is required, mapped values will take the new global 588 // automatically. 589 } else if (DGV->hasAppendingLinkage()) { 590 assert(0 && "Appending linkage unimplemented!"); 591 } else { 592 assert(0 && "Unknown linkage!"); 593 } 594 } else { 595 // Copy the initializer over now... 596 DGV->setInitializer(SInit); 597 } 598 } 599 } 600 return false; 601} 602 603// LinkFunctionProtos - Link the functions together between the two modules, 604// without doing function bodies... this just adds external function prototypes 605// to the Dest function... 606// 607static bool LinkFunctionProtos(Module *Dest, const Module *Src, 608 std::map<const Value*, Value*> &ValueMap, 609 std::string *Err) { 610 // Loop over all of the functions in the src module, mapping them over 611 for (Module::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) { 612 const Function *SF = I; // SrcFunction 613 Function *DF = 0; 614 if (SF->hasName() && !SF->hasInternalLinkage()) { 615 // Check to see if may have to link the function. 616 DF = Dest->getFunction(SF->getName()); 617 if (DF && SF->getType() != DF->getType()) 618 // If types don't agree because of opaque, try to resolve them 619 RecursiveResolveTypes(SF->getType(), DF->getType(), 620 &Dest->getTypeSymbolTable(), ""); 621 } 622 623 if (DF && DF->getType() != SF->getType()) { 624 if (DF->isDeclaration() && !SF->isDeclaration()) { 625 // We have a definition of the same name but different type in the 626 // source module. Copy the prototype to the destination and replace 627 // uses of the destination's prototype with the new prototype. 628 Function *NewDF = new Function(SF->getFunctionType(), SF->getLinkage(), 629 SF->getName(), Dest); 630 CopyGVAttributes(NewDF, SF); 631 632 // Any uses of DF need to change to NewDF, with cast 633 DF->replaceAllUsesWith(ConstantExpr::getBitCast(NewDF, DF->getType())); 634 635 // DF will conflict with NewDF because they both had the same. We must 636 // erase this now so ForceRenaming doesn't assert because DF might 637 // not have internal linkage. 638 DF->eraseFromParent(); 639 640 // If the symbol table renamed the function, but it is an externally 641 // visible symbol, DF must be an existing function with internal 642 // linkage. Rename it. 643 if (NewDF->getName() != SF->getName() && !NewDF->hasInternalLinkage()) 644 ForceRenaming(NewDF, SF->getName()); 645 646 // Remember this mapping so uses in the source module get remapped 647 // later by RemapOperand. 648 ValueMap[SF] = NewDF; 649 } else if (SF->isDeclaration()) { 650 // We have two functions of the same name but different type and the 651 // source is a declaration while the destination is not. Any use of 652 // the source must be mapped to the destination, with a cast. 653 ValueMap[SF] = ConstantExpr::getBitCast(DF, SF->getType()); 654 } else { 655 // We have two functions of the same name but different types and they 656 // are both definitions. This is an error. 657 return Error(Err, "Function '" + DF->getName() + "' defined as both '" + 658 ToStr(SF->getFunctionType(), Src) + "' and '" + 659 ToStr(DF->getFunctionType(), Dest) + "'"); 660 } 661 } else if (!DF || SF->hasInternalLinkage() || DF->hasInternalLinkage()) { 662 // Function does not already exist, simply insert an function signature 663 // identical to SF into the dest module... 664 Function *NewDF = new Function(SF->getFunctionType(), SF->getLinkage(), 665 SF->getName(), Dest); 666 CopyGVAttributes(NewDF, SF); 667 668 // If the LLVM runtime renamed the function, but it is an externally 669 // visible symbol, DF must be an existing function with internal linkage. 670 // Rename it. 671 if (NewDF->getName() != SF->getName() && !NewDF->hasInternalLinkage()) 672 ForceRenaming(NewDF, SF->getName()); 673 674 // ... and remember this mapping... 675 ValueMap.insert(std::make_pair(SF, NewDF)); 676 } else if (SF->isDeclaration()) { 677 // If SF is a declaration or if both SF & DF are declarations, just link 678 // the declarations, we aren't adding anything. 679 if (SF->hasDLLImportLinkage()) { 680 if (DF->isDeclaration()) { 681 ValueMap.insert(std::make_pair(SF, DF)); 682 DF->setLinkage(SF->getLinkage()); 683 } 684 } else { 685 ValueMap.insert(std::make_pair(SF, DF)); 686 } 687 } else if (DF->isDeclaration() && !DF->hasDLLImportLinkage()) { 688 // If DF is external but SF is not... 689 // Link the external functions, update linkage qualifiers 690 ValueMap.insert(std::make_pair(SF, DF)); 691 DF->setLinkage(SF->getLinkage()); 692 } else if (SF->hasWeakLinkage() || SF->hasLinkOnceLinkage()) { 693 // At this point we know that DF has LinkOnce, Weak, or External* linkage. 694 ValueMap.insert(std::make_pair(SF, DF)); 695 696 // Linkonce+Weak = Weak 697 // *+External Weak = * 698 if ((DF->hasLinkOnceLinkage() && SF->hasWeakLinkage()) || 699 DF->hasExternalWeakLinkage()) 700 DF->setLinkage(SF->getLinkage()); 701 } else if (DF->hasWeakLinkage() || DF->hasLinkOnceLinkage()) { 702 // At this point we know that SF has LinkOnce or External* linkage. 703 ValueMap.insert(std::make_pair(SF, DF)); 704 if (!SF->hasLinkOnceLinkage() && !SF->hasExternalWeakLinkage()) 705 // Don't inherit linkonce & external weak linkage 706 DF->setLinkage(SF->getLinkage()); 707 } else if (SF->getLinkage() != DF->getLinkage()) { 708 return Error(Err, "Functions named '" + SF->getName() + 709 "' have different linkage specifiers!"); 710 } else if (SF->hasExternalLinkage()) { 711 // The function is defined identically in both modules!! 712 return Error(Err, "Function '" + 713 ToStr(SF->getFunctionType(), Src) + "':\"" + 714 SF->getName() + "\" - Function is already defined!"); 715 } else { 716 assert(0 && "Unknown linkage configuration found!"); 717 } 718 } 719 return false; 720} 721 722// LinkFunctionBody - Copy the source function over into the dest function and 723// fix up references to values. At this point we know that Dest is an external 724// function, and that Src is not. 725static bool LinkFunctionBody(Function *Dest, Function *Src, 726 std::map<const Value*, Value*> &ValueMap, 727 std::string *Err) { 728 assert(Src && Dest && Dest->isDeclaration() && !Src->isDeclaration()); 729 730 // Go through and convert function arguments over, remembering the mapping. 731 Function::arg_iterator DI = Dest->arg_begin(); 732 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end(); 733 I != E; ++I, ++DI) { 734 DI->setName(I->getName()); // Copy the name information over... 735 736 // Add a mapping to our local map 737 ValueMap.insert(std::make_pair(I, DI)); 738 } 739 740 // Splice the body of the source function into the dest function. 741 Dest->getBasicBlockList().splice(Dest->end(), Src->getBasicBlockList()); 742 743 // At this point, all of the instructions and values of the function are now 744 // copied over. The only problem is that they are still referencing values in 745 // the Source function as operands. Loop through all of the operands of the 746 // functions and patch them up to point to the local versions... 747 // 748 for (Function::iterator BB = Dest->begin(), BE = Dest->end(); BB != BE; ++BB) 749 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) 750 for (Instruction::op_iterator OI = I->op_begin(), OE = I->op_end(); 751 OI != OE; ++OI) 752 if (!isa<Instruction>(*OI) && !isa<BasicBlock>(*OI)) 753 *OI = RemapOperand(*OI, ValueMap); 754 755 // There is no need to map the arguments anymore. 756 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end(); 757 I != E; ++I) 758 ValueMap.erase(I); 759 760 return false; 761} 762 763 764// LinkFunctionBodies - Link in the function bodies that are defined in the 765// source module into the DestModule. This consists basically of copying the 766// function over and fixing up references to values. 767static bool LinkFunctionBodies(Module *Dest, Module *Src, 768 std::map<const Value*, Value*> &ValueMap, 769 std::string *Err) { 770 771 // Loop over all of the functions in the src module, mapping them over as we 772 // go 773 for (Module::iterator SF = Src->begin(), E = Src->end(); SF != E; ++SF) { 774 if (!SF->isDeclaration()) { // No body if function is external 775 Function *DF = cast<Function>(ValueMap[SF]); // Destination function 776 777 // DF not external SF external? 778 if (DF->isDeclaration()) 779 // Only provide the function body if there isn't one already. 780 if (LinkFunctionBody(DF, SF, ValueMap, Err)) 781 return true; 782 } 783 } 784 return false; 785} 786 787// LinkAppendingVars - If there were any appending global variables, link them 788// together now. Return true on error. 789static bool LinkAppendingVars(Module *M, 790 std::multimap<std::string, GlobalVariable *> &AppendingVars, 791 std::string *ErrorMsg) { 792 if (AppendingVars.empty()) return false; // Nothing to do. 793 794 // Loop over the multimap of appending vars, processing any variables with the 795 // same name, forming a new appending global variable with both of the 796 // initializers merged together, then rewrite references to the old variables 797 // and delete them. 798 std::vector<Constant*> Inits; 799 while (AppendingVars.size() > 1) { 800 // Get the first two elements in the map... 801 std::multimap<std::string, 802 GlobalVariable*>::iterator Second = AppendingVars.begin(), First=Second++; 803 804 // If the first two elements are for different names, there is no pair... 805 // Otherwise there is a pair, so link them together... 806 if (First->first == Second->first) { 807 GlobalVariable *G1 = First->second, *G2 = Second->second; 808 const ArrayType *T1 = cast<ArrayType>(G1->getType()->getElementType()); 809 const ArrayType *T2 = cast<ArrayType>(G2->getType()->getElementType()); 810 811 // Check to see that they two arrays agree on type... 812 if (T1->getElementType() != T2->getElementType()) 813 return Error(ErrorMsg, 814 "Appending variables with different element types need to be linked!"); 815 if (G1->isConstant() != G2->isConstant()) 816 return Error(ErrorMsg, 817 "Appending variables linked with different const'ness!"); 818 819 unsigned NewSize = T1->getNumElements() + T2->getNumElements(); 820 ArrayType *NewType = ArrayType::get(T1->getElementType(), NewSize); 821 822 G1->setName(""); // Clear G1's name in case of a conflict! 823 824 // Create the new global variable... 825 GlobalVariable *NG = 826 new GlobalVariable(NewType, G1->isConstant(), G1->getLinkage(), 827 /*init*/0, First->first, M); 828 829 // Merge the initializer... 830 Inits.reserve(NewSize); 831 if (ConstantArray *I = dyn_cast<ConstantArray>(G1->getInitializer())) { 832 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i) 833 Inits.push_back(I->getOperand(i)); 834 } else { 835 assert(isa<ConstantAggregateZero>(G1->getInitializer())); 836 Constant *CV = Constant::getNullValue(T1->getElementType()); 837 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i) 838 Inits.push_back(CV); 839 } 840 if (ConstantArray *I = dyn_cast<ConstantArray>(G2->getInitializer())) { 841 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i) 842 Inits.push_back(I->getOperand(i)); 843 } else { 844 assert(isa<ConstantAggregateZero>(G2->getInitializer())); 845 Constant *CV = Constant::getNullValue(T2->getElementType()); 846 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i) 847 Inits.push_back(CV); 848 } 849 NG->setInitializer(ConstantArray::get(NewType, Inits)); 850 Inits.clear(); 851 852 // Replace any uses of the two global variables with uses of the new 853 // global... 854 855 // FIXME: This should rewrite simple/straight-forward uses such as 856 // getelementptr instructions to not use the Cast! 857 G1->replaceAllUsesWith(ConstantExpr::getBitCast(NG, G1->getType())); 858 G2->replaceAllUsesWith(ConstantExpr::getBitCast(NG, G2->getType())); 859 860 // Remove the two globals from the module now... 861 M->getGlobalList().erase(G1); 862 M->getGlobalList().erase(G2); 863 864 // Put the new global into the AppendingVars map so that we can handle 865 // linking of more than two vars... 866 Second->second = NG; 867 } 868 AppendingVars.erase(First); 869 } 870 871 return false; 872} 873 874 875// LinkModules - This function links two modules together, with the resulting 876// left module modified to be the composite of the two input modules. If an 877// error occurs, true is returned and ErrorMsg (if not null) is set to indicate 878// the problem. Upon failure, the Dest module could be in a modified state, and 879// shouldn't be relied on to be consistent. 880bool 881Linker::LinkModules(Module *Dest, Module *Src, std::string *ErrorMsg) { 882 assert(Dest != 0 && "Invalid Destination module"); 883 assert(Src != 0 && "Invalid Source Module"); 884 885 if (Dest->getDataLayout().empty()) { 886 if (!Src->getDataLayout().empty()) { 887 Dest->setDataLayout(Src->getDataLayout()); 888 } else { 889 std::string DataLayout; 890 891 if (Dest->getEndianness() == Module::AnyEndianness) 892 if (Src->getEndianness() == Module::BigEndian) 893 DataLayout.append("E"); 894 else if (Src->getEndianness() == Module::LittleEndian) 895 DataLayout.append("e"); 896 if (Dest->getPointerSize() == Module::AnyPointerSize) 897 if (Src->getPointerSize() == Module::Pointer64) 898 DataLayout.append(DataLayout.length() == 0 ? "p:64:64" : "-p:64:64"); 899 else if (Src->getPointerSize() == Module::Pointer32) 900 DataLayout.append(DataLayout.length() == 0 ? "p:32:32" : "-p:32:32"); 901 Dest->setDataLayout(DataLayout); 902 } 903 } 904 905 // COpy the target triple from the source to dest if the dest's is empty 906 if (Dest->getTargetTriple().empty() && !Src->getTargetTriple().empty()) 907 Dest->setTargetTriple(Src->getTargetTriple()); 908 909 if (!Src->getDataLayout().empty() && !Dest->getDataLayout().empty() && 910 Src->getDataLayout() != Dest->getDataLayout()) 911 cerr << "WARNING: Linking two modules of different data layouts!\n"; 912 if (!Src->getTargetTriple().empty() && 913 Dest->getTargetTriple() != Src->getTargetTriple()) 914 cerr << "WARNING: Linking two modules of different target triples!\n"; 915 916 // Append the module inline asm string 917 if (!Src->getModuleInlineAsm().empty()) { 918 if (Dest->getModuleInlineAsm().empty()) 919 Dest->setModuleInlineAsm(Src->getModuleInlineAsm()); 920 else 921 Dest->setModuleInlineAsm(Dest->getModuleInlineAsm()+"\n"+ 922 Src->getModuleInlineAsm()); 923 } 924 925 // Update the destination module's dependent libraries list with the libraries 926 // from the source module. There's no opportunity for duplicates here as the 927 // Module ensures that duplicate insertions are discarded. 928 Module::lib_iterator SI = Src->lib_begin(); 929 Module::lib_iterator SE = Src->lib_end(); 930 while ( SI != SE ) { 931 Dest->addLibrary(*SI); 932 ++SI; 933 } 934 935 // LinkTypes - Go through the symbol table of the Src module and see if any 936 // types are named in the src module that are not named in the Dst module. 937 // Make sure there are no type name conflicts. 938 if (LinkTypes(Dest, Src, ErrorMsg)) 939 return true; 940 941 // ValueMap - Mapping of values from what they used to be in Src, to what they 942 // are now in Dest. 943 std::map<const Value*, Value*> ValueMap; 944 945 // AppendingVars - Keep track of global variables in the destination module 946 // with appending linkage. After the module is linked together, they are 947 // appended and the module is rewritten. 948 std::multimap<std::string, GlobalVariable *> AppendingVars; 949 for (Module::global_iterator I = Dest->global_begin(), E = Dest->global_end(); 950 I != E; ++I) { 951 // Add all of the appending globals already in the Dest module to 952 // AppendingVars. 953 if (I->hasAppendingLinkage()) 954 AppendingVars.insert(std::make_pair(I->getName(), I)); 955 } 956 957 // Insert all of the globals in src into the Dest module... without linking 958 // initializers (which could refer to functions not yet mapped over). 959 if (LinkGlobals(Dest, Src, ValueMap, AppendingVars, ErrorMsg)) 960 return true; 961 962 // Link the functions together between the two modules, without doing function 963 // bodies... this just adds external function prototypes to the Dest 964 // function... We do this so that when we begin processing function bodies, 965 // all of the global values that may be referenced are available in our 966 // ValueMap. 967 if (LinkFunctionProtos(Dest, Src, ValueMap, ErrorMsg)) 968 return true; 969 970 // Update the initializers in the Dest module now that all globals that may 971 // be referenced are in Dest. 972 if (LinkGlobalInits(Dest, Src, ValueMap, ErrorMsg)) return true; 973 974 // Link in the function bodies that are defined in the source module into the 975 // DestModule. This consists basically of copying the function over and 976 // fixing up references to values. 977 if (LinkFunctionBodies(Dest, Src, ValueMap, ErrorMsg)) return true; 978 979 // If there were any appending global variables, link them together now. 980 if (LinkAppendingVars(Dest, AppendingVars, ErrorMsg)) return true; 981 982 // If the source library's module id is in the dependent library list of the 983 // destination library, remove it since that module is now linked in. 984 sys::Path modId; 985 modId.set(Src->getModuleIdentifier()); 986 if (!modId.isEmpty()) 987 Dest->removeLibrary(modId.getBasename()); 988 989 return false; 990} 991 992// vim: sw=2 993