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 //===----------------------------------------------------------------------===// 13 14 #include "llvm/Linker.h" 15 #include "llvm/Constants.h" 16 #include "llvm/DerivedTypes.h" 17 #include "llvm/Instructions.h" 18 #include "llvm/Module.h" 19 #include "llvm/ADT/DenseSet.h" 20 #include "llvm/ADT/Optional.h" 21 #include "llvm/ADT/SetVector.h" 22 #include "llvm/ADT/SmallPtrSet.h" 23 #include "llvm/Support/Debug.h" 24 #include "llvm/Support/Path.h" 25 #include "llvm/Support/raw_ostream.h" 26 #include "llvm/Transforms/Utils/Cloning.h" 27 #include "llvm/Transforms/Utils/ValueMapper.h" 28 #include <cctype> 29 using namespace llvm; 30 31 //===----------------------------------------------------------------------===// 32 // TypeMap implementation. 33 //===----------------------------------------------------------------------===// 34 35 namespace { 36 class TypeMapTy : public ValueMapTypeRemapper { 37 /// MappedTypes - This is a mapping from a source type to a destination type 38 /// to use. 39 DenseMap<Type*, Type*> MappedTypes; 40 41 /// SpeculativeTypes - When checking to see if two subgraphs are isomorphic, 42 /// we speculatively add types to MappedTypes, but keep track of them here in 43 /// case we need to roll back. 44 SmallVector<Type*, 16> SpeculativeTypes; 45 46 /// SrcDefinitionsToResolve - This is a list of non-opaque structs in the 47 /// source module that are mapped to an opaque struct in the destination 48 /// module. 49 SmallVector<StructType*, 16> SrcDefinitionsToResolve; 50 51 /// DstResolvedOpaqueTypes - This is the set of opaque types in the 52 /// destination modules who are getting a body from the source module. 53 SmallPtrSet<StructType*, 16> DstResolvedOpaqueTypes; 54 55 public: 56 /// addTypeMapping - Indicate that the specified type in the destination 57 /// module is conceptually equivalent to the specified type in the source 58 /// module. 59 void addTypeMapping(Type *DstTy, Type *SrcTy); 60 61 /// linkDefinedTypeBodies - Produce a body for an opaque type in the dest 62 /// module from a type definition in the source module. 63 void linkDefinedTypeBodies(); 64 65 /// get - Return the mapped type to use for the specified input type from the 66 /// source module. 67 Type *get(Type *SrcTy); 68 69 FunctionType *get(FunctionType *T) {return cast<FunctionType>(get((Type*)T));} 70 71 /// dump - Dump out the type map for debugging purposes. 72 void dump() const { 73 for (DenseMap<Type*, Type*>::const_iterator 74 I = MappedTypes.begin(), E = MappedTypes.end(); I != E; ++I) { 75 dbgs() << "TypeMap: "; 76 I->first->dump(); 77 dbgs() << " => "; 78 I->second->dump(); 79 dbgs() << '\n'; 80 } 81 } 82 83 private: 84 Type *getImpl(Type *T); 85 /// remapType - Implement the ValueMapTypeRemapper interface. 86 Type *remapType(Type *SrcTy) { 87 return get(SrcTy); 88 } 89 90 bool areTypesIsomorphic(Type *DstTy, Type *SrcTy); 91 }; 92 } 93 94 void TypeMapTy::addTypeMapping(Type *DstTy, Type *SrcTy) { 95 Type *&Entry = MappedTypes[SrcTy]; 96 if (Entry) return; 97 98 if (DstTy == SrcTy) { 99 Entry = DstTy; 100 return; 101 } 102 103 // Check to see if these types are recursively isomorphic and establish a 104 // mapping between them if so. 105 if (!areTypesIsomorphic(DstTy, SrcTy)) { 106 // Oops, they aren't isomorphic. Just discard this request by rolling out 107 // any speculative mappings we've established. 108 for (unsigned i = 0, e = SpeculativeTypes.size(); i != e; ++i) 109 MappedTypes.erase(SpeculativeTypes[i]); 110 } 111 SpeculativeTypes.clear(); 112 } 113 114 /// areTypesIsomorphic - Recursively walk this pair of types, returning true 115 /// if they are isomorphic, false if they are not. 116 bool TypeMapTy::areTypesIsomorphic(Type *DstTy, Type *SrcTy) { 117 // Two types with differing kinds are clearly not isomorphic. 118 if (DstTy->getTypeID() != SrcTy->getTypeID()) return false; 119 120 // If we have an entry in the MappedTypes table, then we have our answer. 121 Type *&Entry = MappedTypes[SrcTy]; 122 if (Entry) 123 return Entry == DstTy; 124 125 // Two identical types are clearly isomorphic. Remember this 126 // non-speculatively. 127 if (DstTy == SrcTy) { 128 Entry = DstTy; 129 return true; 130 } 131 132 // Okay, we have two types with identical kinds that we haven't seen before. 133 134 // If this is an opaque struct type, special case it. 135 if (StructType *SSTy = dyn_cast<StructType>(SrcTy)) { 136 // Mapping an opaque type to any struct, just keep the dest struct. 137 if (SSTy->isOpaque()) { 138 Entry = DstTy; 139 SpeculativeTypes.push_back(SrcTy); 140 return true; 141 } 142 143 // Mapping a non-opaque source type to an opaque dest. If this is the first 144 // type that we're mapping onto this destination type then we succeed. Keep 145 // the dest, but fill it in later. This doesn't need to be speculative. If 146 // this is the second (different) type that we're trying to map onto the 147 // same opaque type then we fail. 148 if (cast<StructType>(DstTy)->isOpaque()) { 149 // We can only map one source type onto the opaque destination type. 150 if (!DstResolvedOpaqueTypes.insert(cast<StructType>(DstTy))) 151 return false; 152 SrcDefinitionsToResolve.push_back(SSTy); 153 Entry = DstTy; 154 return true; 155 } 156 } 157 158 // If the number of subtypes disagree between the two types, then we fail. 159 if (SrcTy->getNumContainedTypes() != DstTy->getNumContainedTypes()) 160 return false; 161 162 // Fail if any of the extra properties (e.g. array size) of the type disagree. 163 if (isa<IntegerType>(DstTy)) 164 return false; // bitwidth disagrees. 165 if (PointerType *PT = dyn_cast<PointerType>(DstTy)) { 166 if (PT->getAddressSpace() != cast<PointerType>(SrcTy)->getAddressSpace()) 167 return false; 168 169 } else if (FunctionType *FT = dyn_cast<FunctionType>(DstTy)) { 170 if (FT->isVarArg() != cast<FunctionType>(SrcTy)->isVarArg()) 171 return false; 172 } else if (StructType *DSTy = dyn_cast<StructType>(DstTy)) { 173 StructType *SSTy = cast<StructType>(SrcTy); 174 if (DSTy->isLiteral() != SSTy->isLiteral() || 175 DSTy->isPacked() != SSTy->isPacked()) 176 return false; 177 } else if (ArrayType *DATy = dyn_cast<ArrayType>(DstTy)) { 178 if (DATy->getNumElements() != cast<ArrayType>(SrcTy)->getNumElements()) 179 return false; 180 } else if (VectorType *DVTy = dyn_cast<VectorType>(DstTy)) { 181 if (DVTy->getNumElements() != cast<ArrayType>(SrcTy)->getNumElements()) 182 return false; 183 } 184 185 // Otherwise, we speculate that these two types will line up and recursively 186 // check the subelements. 187 Entry = DstTy; 188 SpeculativeTypes.push_back(SrcTy); 189 190 for (unsigned i = 0, e = SrcTy->getNumContainedTypes(); i != e; ++i) 191 if (!areTypesIsomorphic(DstTy->getContainedType(i), 192 SrcTy->getContainedType(i))) 193 return false; 194 195 // If everything seems to have lined up, then everything is great. 196 return true; 197 } 198 199 /// linkDefinedTypeBodies - Produce a body for an opaque type in the dest 200 /// module from a type definition in the source module. 201 void TypeMapTy::linkDefinedTypeBodies() { 202 SmallVector<Type*, 16> Elements; 203 SmallString<16> TmpName; 204 205 // Note that processing entries in this loop (calling 'get') can add new 206 // entries to the SrcDefinitionsToResolve vector. 207 while (!SrcDefinitionsToResolve.empty()) { 208 StructType *SrcSTy = SrcDefinitionsToResolve.pop_back_val(); 209 StructType *DstSTy = cast<StructType>(MappedTypes[SrcSTy]); 210 211 // TypeMap is a many-to-one mapping, if there were multiple types that 212 // provide a body for DstSTy then previous iterations of this loop may have 213 // already handled it. Just ignore this case. 214 if (!DstSTy->isOpaque()) continue; 215 assert(!SrcSTy->isOpaque() && "Not resolving a definition?"); 216 217 // Map the body of the source type over to a new body for the dest type. 218 Elements.resize(SrcSTy->getNumElements()); 219 for (unsigned i = 0, e = Elements.size(); i != e; ++i) 220 Elements[i] = getImpl(SrcSTy->getElementType(i)); 221 222 DstSTy->setBody(Elements, SrcSTy->isPacked()); 223 224 // If DstSTy has no name or has a longer name than STy, then viciously steal 225 // STy's name. 226 if (!SrcSTy->hasName()) continue; 227 StringRef SrcName = SrcSTy->getName(); 228 229 if (!DstSTy->hasName() || DstSTy->getName().size() > SrcName.size()) { 230 TmpName.insert(TmpName.end(), SrcName.begin(), SrcName.end()); 231 SrcSTy->setName(""); 232 DstSTy->setName(TmpName.str()); 233 TmpName.clear(); 234 } 235 } 236 237 DstResolvedOpaqueTypes.clear(); 238 } 239 240 /// get - Return the mapped type to use for the specified input type from the 241 /// source module. 242 Type *TypeMapTy::get(Type *Ty) { 243 Type *Result = getImpl(Ty); 244 245 // If this caused a reference to any struct type, resolve it before returning. 246 if (!SrcDefinitionsToResolve.empty()) 247 linkDefinedTypeBodies(); 248 return Result; 249 } 250 251 /// getImpl - This is the recursive version of get(). 252 Type *TypeMapTy::getImpl(Type *Ty) { 253 // If we already have an entry for this type, return it. 254 Type **Entry = &MappedTypes[Ty]; 255 if (*Entry) return *Entry; 256 257 // If this is not a named struct type, then just map all of the elements and 258 // then rebuild the type from inside out. 259 if (!isa<StructType>(Ty) || cast<StructType>(Ty)->isLiteral()) { 260 // If there are no element types to map, then the type is itself. This is 261 // true for the anonymous {} struct, things like 'float', integers, etc. 262 if (Ty->getNumContainedTypes() == 0) 263 return *Entry = Ty; 264 265 // Remap all of the elements, keeping track of whether any of them change. 266 bool AnyChange = false; 267 SmallVector<Type*, 4> ElementTypes; 268 ElementTypes.resize(Ty->getNumContainedTypes()); 269 for (unsigned i = 0, e = Ty->getNumContainedTypes(); i != e; ++i) { 270 ElementTypes[i] = getImpl(Ty->getContainedType(i)); 271 AnyChange |= ElementTypes[i] != Ty->getContainedType(i); 272 } 273 274 // If we found our type while recursively processing stuff, just use it. 275 Entry = &MappedTypes[Ty]; 276 if (*Entry) return *Entry; 277 278 // If all of the element types mapped directly over, then the type is usable 279 // as-is. 280 if (!AnyChange) 281 return *Entry = Ty; 282 283 // Otherwise, rebuild a modified type. 284 switch (Ty->getTypeID()) { 285 default: llvm_unreachable("unknown derived type to remap"); 286 case Type::ArrayTyID: 287 return *Entry = ArrayType::get(ElementTypes[0], 288 cast<ArrayType>(Ty)->getNumElements()); 289 case Type::VectorTyID: 290 return *Entry = VectorType::get(ElementTypes[0], 291 cast<VectorType>(Ty)->getNumElements()); 292 case Type::PointerTyID: 293 return *Entry = PointerType::get(ElementTypes[0], 294 cast<PointerType>(Ty)->getAddressSpace()); 295 case Type::FunctionTyID: 296 return *Entry = FunctionType::get(ElementTypes[0], 297 makeArrayRef(ElementTypes).slice(1), 298 cast<FunctionType>(Ty)->isVarArg()); 299 case Type::StructTyID: 300 // Note that this is only reached for anonymous structs. 301 return *Entry = StructType::get(Ty->getContext(), ElementTypes, 302 cast<StructType>(Ty)->isPacked()); 303 } 304 } 305 306 // Otherwise, this is an unmapped named struct. If the struct can be directly 307 // mapped over, just use it as-is. This happens in a case when the linked-in 308 // module has something like: 309 // %T = type {%T*, i32} 310 // @GV = global %T* null 311 // where T does not exist at all in the destination module. 312 // 313 // The other case we watch for is when the type is not in the destination 314 // module, but that it has to be rebuilt because it refers to something that 315 // is already mapped. For example, if the destination module has: 316 // %A = type { i32 } 317 // and the source module has something like 318 // %A' = type { i32 } 319 // %B = type { %A'* } 320 // @GV = global %B* null 321 // then we want to create a new type: "%B = type { %A*}" and have it take the 322 // pristine "%B" name from the source module. 323 // 324 // To determine which case this is, we have to recursively walk the type graph 325 // speculating that we'll be able to reuse it unmodified. Only if this is 326 // safe would we map the entire thing over. Because this is an optimization, 327 // and is not required for the prettiness of the linked module, we just skip 328 // it and always rebuild a type here. 329 StructType *STy = cast<StructType>(Ty); 330 331 // If the type is opaque, we can just use it directly. 332 if (STy->isOpaque()) 333 return *Entry = STy; 334 335 // Otherwise we create a new type and resolve its body later. This will be 336 // resolved by the top level of get(). 337 SrcDefinitionsToResolve.push_back(STy); 338 StructType *DTy = StructType::create(STy->getContext()); 339 DstResolvedOpaqueTypes.insert(DTy); 340 return *Entry = DTy; 341 } 342 343 //===----------------------------------------------------------------------===// 344 // ModuleLinker implementation. 345 //===----------------------------------------------------------------------===// 346 347 namespace { 348 /// ModuleLinker - This is an implementation class for the LinkModules 349 /// function, which is the entrypoint for this file. 350 class ModuleLinker { 351 Module *DstM, *SrcM; 352 353 TypeMapTy TypeMap; 354 355 /// ValueMap - Mapping of values from what they used to be in Src, to what 356 /// they are now in DstM. ValueToValueMapTy is a ValueMap, which involves 357 /// some overhead due to the use of Value handles which the Linker doesn't 358 /// actually need, but this allows us to reuse the ValueMapper code. 359 ValueToValueMapTy ValueMap; 360 361 struct AppendingVarInfo { 362 GlobalVariable *NewGV; // New aggregate global in dest module. 363 Constant *DstInit; // Old initializer from dest module. 364 Constant *SrcInit; // Old initializer from src module. 365 }; 366 367 std::vector<AppendingVarInfo> AppendingVars; 368 369 unsigned Mode; // Mode to treat source module. 370 371 // Set of items not to link in from source. 372 SmallPtrSet<const Value*, 16> DoNotLinkFromSource; 373 374 // Vector of functions to lazily link in. 375 std::vector<Function*> LazilyLinkFunctions; 376 377 public: 378 std::string ErrorMsg; 379 380 ModuleLinker(Module *dstM, Module *srcM, unsigned mode) 381 : DstM(dstM), SrcM(srcM), Mode(mode) { } 382 383 bool run(); 384 385 private: 386 /// emitError - Helper method for setting a message and returning an error 387 /// code. 388 bool emitError(const Twine &Message) { 389 ErrorMsg = Message.str(); 390 return true; 391 } 392 393 /// getLinkageResult - This analyzes the two global values and determines 394 /// what the result will look like in the destination module. 395 bool getLinkageResult(GlobalValue *Dest, const GlobalValue *Src, 396 GlobalValue::LinkageTypes <, 397 GlobalValue::VisibilityTypes &Vis, 398 bool &LinkFromSrc); 399 400 /// getLinkedToGlobal - Given a global in the source module, return the 401 /// global in the destination module that is being linked to, if any. 402 GlobalValue *getLinkedToGlobal(GlobalValue *SrcGV) { 403 // If the source has no name it can't link. If it has local linkage, 404 // there is no name match-up going on. 405 if (!SrcGV->hasName() || SrcGV->hasLocalLinkage()) 406 return 0; 407 408 // Otherwise see if we have a match in the destination module's symtab. 409 GlobalValue *DGV = DstM->getNamedValue(SrcGV->getName()); 410 if (DGV == 0) return 0; 411 412 // If we found a global with the same name in the dest module, but it has 413 // internal linkage, we are really not doing any linkage here. 414 if (DGV->hasLocalLinkage()) 415 return 0; 416 417 // Otherwise, we do in fact link to the destination global. 418 return DGV; 419 } 420 421 void computeTypeMapping(); 422 bool categorizeModuleFlagNodes(const NamedMDNode *ModFlags, 423 DenseMap<MDString*, MDNode*> &ErrorNode, 424 DenseMap<MDString*, MDNode*> &WarningNode, 425 DenseMap<MDString*, MDNode*> &OverrideNode, 426 DenseMap<MDString*, 427 SmallSetVector<MDNode*, 8> > &RequireNodes, 428 SmallSetVector<MDString*, 16> &SeenIDs); 429 430 bool linkAppendingVarProto(GlobalVariable *DstGV, GlobalVariable *SrcGV); 431 bool linkGlobalProto(GlobalVariable *SrcGV); 432 bool linkFunctionProto(Function *SrcF); 433 bool linkAliasProto(GlobalAlias *SrcA); 434 bool linkModuleFlagsMetadata(); 435 436 void linkAppendingVarInit(const AppendingVarInfo &AVI); 437 void linkGlobalInits(); 438 void linkFunctionBody(Function *Dst, Function *Src); 439 void linkAliasBodies(); 440 void linkNamedMDNodes(); 441 }; 442 } 443 444 /// forceRenaming - The LLVM SymbolTable class autorenames globals that conflict 445 /// in the symbol table. This is good for all clients except for us. Go 446 /// through the trouble to force this back. 447 static void forceRenaming(GlobalValue *GV, StringRef Name) { 448 // If the global doesn't force its name or if it already has the right name, 449 // there is nothing for us to do. 450 if (GV->hasLocalLinkage() || GV->getName() == Name) 451 return; 452 453 Module *M = GV->getParent(); 454 455 // If there is a conflict, rename the conflict. 456 if (GlobalValue *ConflictGV = M->getNamedValue(Name)) { 457 GV->takeName(ConflictGV); 458 ConflictGV->setName(Name); // This will cause ConflictGV to get renamed 459 assert(ConflictGV->getName() != Name && "forceRenaming didn't work"); 460 } else { 461 GV->setName(Name); // Force the name back 462 } 463 } 464 465 /// copyGVAttributes - copy additional attributes (those not needed to construct 466 /// a GlobalValue) from the SrcGV to the DestGV. 467 static void copyGVAttributes(GlobalValue *DestGV, const GlobalValue *SrcGV) { 468 // Use the maximum alignment, rather than just copying the alignment of SrcGV. 469 unsigned Alignment = std::max(DestGV->getAlignment(), SrcGV->getAlignment()); 470 DestGV->copyAttributesFrom(SrcGV); 471 DestGV->setAlignment(Alignment); 472 473 forceRenaming(DestGV, SrcGV->getName()); 474 } 475 476 static bool isLessConstraining(GlobalValue::VisibilityTypes a, 477 GlobalValue::VisibilityTypes b) { 478 if (a == GlobalValue::HiddenVisibility) 479 return false; 480 if (b == GlobalValue::HiddenVisibility) 481 return true; 482 if (a == GlobalValue::ProtectedVisibility) 483 return false; 484 if (b == GlobalValue::ProtectedVisibility) 485 return true; 486 return false; 487 } 488 489 /// getLinkageResult - This analyzes the two global values and determines what 490 /// the result will look like in the destination module. In particular, it 491 /// computes the resultant linkage type and visibility, computes whether the 492 /// global in the source should be copied over to the destination (replacing 493 /// the existing one), and computes whether this linkage is an error or not. 494 bool ModuleLinker::getLinkageResult(GlobalValue *Dest, const GlobalValue *Src, 495 GlobalValue::LinkageTypes <, 496 GlobalValue::VisibilityTypes &Vis, 497 bool &LinkFromSrc) { 498 assert(Dest && "Must have two globals being queried"); 499 assert(!Src->hasLocalLinkage() && 500 "If Src has internal linkage, Dest shouldn't be set!"); 501 502 bool SrcIsDeclaration = Src->isDeclaration() && !Src->isMaterializable(); 503 bool DestIsDeclaration = Dest->isDeclaration(); 504 505 if (SrcIsDeclaration) { 506 // If Src is external or if both Src & Dest are external.. Just link the 507 // external globals, we aren't adding anything. 508 if (Src->hasDLLImportLinkage()) { 509 // If one of GVs has DLLImport linkage, result should be dllimport'ed. 510 if (DestIsDeclaration) { 511 LinkFromSrc = true; 512 LT = Src->getLinkage(); 513 } 514 } else if (Dest->hasExternalWeakLinkage()) { 515 // If the Dest is weak, use the source linkage. 516 LinkFromSrc = true; 517 LT = Src->getLinkage(); 518 } else { 519 LinkFromSrc = false; 520 LT = Dest->getLinkage(); 521 } 522 } else if (DestIsDeclaration && !Dest->hasDLLImportLinkage()) { 523 // If Dest is external but Src is not: 524 LinkFromSrc = true; 525 LT = Src->getLinkage(); 526 } else if (Src->isWeakForLinker()) { 527 // At this point we know that Dest has LinkOnce, External*, Weak, Common, 528 // or DLL* linkage. 529 if (Dest->hasExternalWeakLinkage() || 530 Dest->hasAvailableExternallyLinkage() || 531 (Dest->hasLinkOnceLinkage() && 532 (Src->hasWeakLinkage() || Src->hasCommonLinkage()))) { 533 LinkFromSrc = true; 534 LT = Src->getLinkage(); 535 } else { 536 LinkFromSrc = false; 537 LT = Dest->getLinkage(); 538 } 539 } else if (Dest->isWeakForLinker()) { 540 // At this point we know that Src has External* or DLL* linkage. 541 if (Src->hasExternalWeakLinkage()) { 542 LinkFromSrc = false; 543 LT = Dest->getLinkage(); 544 } else { 545 LinkFromSrc = true; 546 LT = GlobalValue::ExternalLinkage; 547 } 548 } else { 549 assert((Dest->hasExternalLinkage() || Dest->hasDLLImportLinkage() || 550 Dest->hasDLLExportLinkage() || Dest->hasExternalWeakLinkage()) && 551 (Src->hasExternalLinkage() || Src->hasDLLImportLinkage() || 552 Src->hasDLLExportLinkage() || Src->hasExternalWeakLinkage()) && 553 "Unexpected linkage type!"); 554 return emitError("Linking globals named '" + Src->getName() + 555 "': symbol multiply defined!"); 556 } 557 558 // Compute the visibility. We follow the rules in the System V Application 559 // Binary Interface. 560 Vis = isLessConstraining(Src->getVisibility(), Dest->getVisibility()) ? 561 Dest->getVisibility() : Src->getVisibility(); 562 return false; 563 } 564 565 /// computeTypeMapping - Loop over all of the linked values to compute type 566 /// mappings. For example, if we link "extern Foo *x" and "Foo *x = NULL", then 567 /// we have two struct types 'Foo' but one got renamed when the module was 568 /// loaded into the same LLVMContext. 569 void ModuleLinker::computeTypeMapping() { 570 // Incorporate globals. 571 for (Module::global_iterator I = SrcM->global_begin(), 572 E = SrcM->global_end(); I != E; ++I) { 573 GlobalValue *DGV = getLinkedToGlobal(I); 574 if (DGV == 0) continue; 575 576 if (!DGV->hasAppendingLinkage() || !I->hasAppendingLinkage()) { 577 TypeMap.addTypeMapping(DGV->getType(), I->getType()); 578 continue; 579 } 580 581 // Unify the element type of appending arrays. 582 ArrayType *DAT = cast<ArrayType>(DGV->getType()->getElementType()); 583 ArrayType *SAT = cast<ArrayType>(I->getType()->getElementType()); 584 TypeMap.addTypeMapping(DAT->getElementType(), SAT->getElementType()); 585 } 586 587 // Incorporate functions. 588 for (Module::iterator I = SrcM->begin(), E = SrcM->end(); I != E; ++I) { 589 if (GlobalValue *DGV = getLinkedToGlobal(I)) 590 TypeMap.addTypeMapping(DGV->getType(), I->getType()); 591 } 592 593 // Incorporate types by name, scanning all the types in the source module. 594 // At this point, the destination module may have a type "%foo = { i32 }" for 595 // example. When the source module got loaded into the same LLVMContext, if 596 // it had the same type, it would have been renamed to "%foo.42 = { i32 }". 597 std::vector<StructType*> SrcStructTypes; 598 SrcM->findUsedStructTypes(SrcStructTypes); 599 SmallPtrSet<StructType*, 32> SrcStructTypesSet(SrcStructTypes.begin(), 600 SrcStructTypes.end()); 601 602 std::vector<StructType*> DstStructTypes; 603 DstM->findUsedStructTypes(DstStructTypes); 604 SmallPtrSet<StructType*, 32> DstStructTypesSet(DstStructTypes.begin(), 605 DstStructTypes.end()); 606 607 for (unsigned i = 0, e = SrcStructTypes.size(); i != e; ++i) { 608 StructType *ST = SrcStructTypes[i]; 609 if (!ST->hasName()) continue; 610 611 // Check to see if there is a dot in the name followed by a digit. 612 size_t DotPos = ST->getName().rfind('.'); 613 if (DotPos == 0 || DotPos == StringRef::npos || 614 ST->getName().back() == '.' || !isdigit(ST->getName()[DotPos+1])) 615 continue; 616 617 // Check to see if the destination module has a struct with the prefix name. 618 if (StructType *DST = DstM->getTypeByName(ST->getName().substr(0, DotPos))) 619 // Don't use it if this actually came from the source module. They're in 620 // the same LLVMContext after all. Also don't use it unless the type is 621 // actually used in the destination module. This can happen in situations 622 // like this: 623 // 624 // Module A Module B 625 // -------- -------- 626 // %Z = type { %A } %B = type { %C.1 } 627 // %A = type { %B.1, [7 x i8] } %C.1 = type { i8* } 628 // %B.1 = type { %C } %A.2 = type { %B.3, [5 x i8] } 629 // %C = type { i8* } %B.3 = type { %C.1 } 630 // 631 // When we link Module B with Module A, the '%B' in Module B is 632 // used. However, that would then use '%C.1'. But when we process '%C.1', 633 // we prefer to take the '%C' version. So we are then left with both 634 // '%C.1' and '%C' being used for the same types. This leads to some 635 // variables using one type and some using the other. 636 if (!SrcStructTypesSet.count(DST) && DstStructTypesSet.count(DST)) 637 TypeMap.addTypeMapping(DST, ST); 638 } 639 640 // Don't bother incorporating aliases, they aren't generally typed well. 641 642 // Now that we have discovered all of the type equivalences, get a body for 643 // any 'opaque' types in the dest module that are now resolved. 644 TypeMap.linkDefinedTypeBodies(); 645 } 646 647 /// linkAppendingVarProto - If there were any appending global variables, link 648 /// them together now. Return true on error. 649 bool ModuleLinker::linkAppendingVarProto(GlobalVariable *DstGV, 650 GlobalVariable *SrcGV) { 651 652 if (!SrcGV->hasAppendingLinkage() || !DstGV->hasAppendingLinkage()) 653 return emitError("Linking globals named '" + SrcGV->getName() + 654 "': can only link appending global with another appending global!"); 655 656 ArrayType *DstTy = cast<ArrayType>(DstGV->getType()->getElementType()); 657 ArrayType *SrcTy = 658 cast<ArrayType>(TypeMap.get(SrcGV->getType()->getElementType())); 659 Type *EltTy = DstTy->getElementType(); 660 661 // Check to see that they two arrays agree on type. 662 if (EltTy != SrcTy->getElementType()) 663 return emitError("Appending variables with different element types!"); 664 if (DstGV->isConstant() != SrcGV->isConstant()) 665 return emitError("Appending variables linked with different const'ness!"); 666 667 if (DstGV->getAlignment() != SrcGV->getAlignment()) 668 return emitError( 669 "Appending variables with different alignment need to be linked!"); 670 671 if (DstGV->getVisibility() != SrcGV->getVisibility()) 672 return emitError( 673 "Appending variables with different visibility need to be linked!"); 674 675 if (DstGV->getSection() != SrcGV->getSection()) 676 return emitError( 677 "Appending variables with different section name need to be linked!"); 678 679 uint64_t NewSize = DstTy->getNumElements() + SrcTy->getNumElements(); 680 ArrayType *NewType = ArrayType::get(EltTy, NewSize); 681 682 // Create the new global variable. 683 GlobalVariable *NG = 684 new GlobalVariable(*DstGV->getParent(), NewType, SrcGV->isConstant(), 685 DstGV->getLinkage(), /*init*/0, /*name*/"", DstGV, 686 DstGV->isThreadLocal(), 687 DstGV->getType()->getAddressSpace()); 688 689 // Propagate alignment, visibility and section info. 690 copyGVAttributes(NG, DstGV); 691 692 AppendingVarInfo AVI; 693 AVI.NewGV = NG; 694 AVI.DstInit = DstGV->getInitializer(); 695 AVI.SrcInit = SrcGV->getInitializer(); 696 AppendingVars.push_back(AVI); 697 698 // Replace any uses of the two global variables with uses of the new 699 // global. 700 ValueMap[SrcGV] = ConstantExpr::getBitCast(NG, TypeMap.get(SrcGV->getType())); 701 702 DstGV->replaceAllUsesWith(ConstantExpr::getBitCast(NG, DstGV->getType())); 703 DstGV->eraseFromParent(); 704 705 // Track the source variable so we don't try to link it. 706 DoNotLinkFromSource.insert(SrcGV); 707 708 return false; 709 } 710 711 /// linkGlobalProto - Loop through the global variables in the src module and 712 /// merge them into the dest module. 713 bool ModuleLinker::linkGlobalProto(GlobalVariable *SGV) { 714 GlobalValue *DGV = getLinkedToGlobal(SGV); 715 llvm::Optional<GlobalValue::VisibilityTypes> NewVisibility; 716 717 if (DGV) { 718 // Concatenation of appending linkage variables is magic and handled later. 719 if (DGV->hasAppendingLinkage() || SGV->hasAppendingLinkage()) 720 return linkAppendingVarProto(cast<GlobalVariable>(DGV), SGV); 721 722 // Determine whether linkage of these two globals follows the source 723 // module's definition or the destination module's definition. 724 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; 725 GlobalValue::VisibilityTypes NV; 726 bool LinkFromSrc = false; 727 if (getLinkageResult(DGV, SGV, NewLinkage, NV, LinkFromSrc)) 728 return true; 729 NewVisibility = NV; 730 731 // If we're not linking from the source, then keep the definition that we 732 // have. 733 if (!LinkFromSrc) { 734 // Special case for const propagation. 735 if (GlobalVariable *DGVar = dyn_cast<GlobalVariable>(DGV)) 736 if (DGVar->isDeclaration() && SGV->isConstant() && !DGVar->isConstant()) 737 DGVar->setConstant(true); 738 739 // Set calculated linkage and visibility. 740 DGV->setLinkage(NewLinkage); 741 DGV->setVisibility(*NewVisibility); 742 743 // Make sure to remember this mapping. 744 ValueMap[SGV] = ConstantExpr::getBitCast(DGV,TypeMap.get(SGV->getType())); 745 746 // Track the source global so that we don't attempt to copy it over when 747 // processing global initializers. 748 DoNotLinkFromSource.insert(SGV); 749 750 return false; 751 } 752 } 753 754 // No linking to be performed or linking from the source: simply create an 755 // identical version of the symbol over in the dest module... the 756 // initializer will be filled in later by LinkGlobalInits. 757 GlobalVariable *NewDGV = 758 new GlobalVariable(*DstM, TypeMap.get(SGV->getType()->getElementType()), 759 SGV->isConstant(), SGV->getLinkage(), /*init*/0, 760 SGV->getName(), /*insertbefore*/0, 761 SGV->isThreadLocal(), 762 SGV->getType()->getAddressSpace()); 763 // Propagate alignment, visibility and section info. 764 copyGVAttributes(NewDGV, SGV); 765 if (NewVisibility) 766 NewDGV->setVisibility(*NewVisibility); 767 768 if (DGV) { 769 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDGV, DGV->getType())); 770 DGV->eraseFromParent(); 771 } 772 773 // Make sure to remember this mapping. 774 ValueMap[SGV] = NewDGV; 775 return false; 776 } 777 778 /// linkFunctionProto - Link the function in the source module into the 779 /// destination module if needed, setting up mapping information. 780 bool ModuleLinker::linkFunctionProto(Function *SF) { 781 GlobalValue *DGV = getLinkedToGlobal(SF); 782 llvm::Optional<GlobalValue::VisibilityTypes> NewVisibility; 783 784 if (DGV) { 785 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; 786 bool LinkFromSrc = false; 787 GlobalValue::VisibilityTypes NV; 788 if (getLinkageResult(DGV, SF, NewLinkage, NV, LinkFromSrc)) 789 return true; 790 NewVisibility = NV; 791 792 if (!LinkFromSrc) { 793 // Set calculated linkage 794 DGV->setLinkage(NewLinkage); 795 DGV->setVisibility(*NewVisibility); 796 797 // Make sure to remember this mapping. 798 ValueMap[SF] = ConstantExpr::getBitCast(DGV, TypeMap.get(SF->getType())); 799 800 // Track the function from the source module so we don't attempt to remap 801 // it. 802 DoNotLinkFromSource.insert(SF); 803 804 return false; 805 } 806 } 807 808 // If there is no linkage to be performed or we are linking from the source, 809 // bring SF over. 810 Function *NewDF = Function::Create(TypeMap.get(SF->getFunctionType()), 811 SF->getLinkage(), SF->getName(), DstM); 812 copyGVAttributes(NewDF, SF); 813 if (NewVisibility) 814 NewDF->setVisibility(*NewVisibility); 815 816 if (DGV) { 817 // Any uses of DF need to change to NewDF, with cast. 818 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDF, DGV->getType())); 819 DGV->eraseFromParent(); 820 } else { 821 // Internal, LO_ODR, or LO linkage - stick in set to ignore and lazily link. 822 if (SF->hasLocalLinkage() || SF->hasLinkOnceLinkage() || 823 SF->hasAvailableExternallyLinkage()) { 824 DoNotLinkFromSource.insert(SF); 825 LazilyLinkFunctions.push_back(SF); 826 } 827 } 828 829 ValueMap[SF] = NewDF; 830 return false; 831 } 832 833 /// LinkAliasProto - Set up prototypes for any aliases that come over from the 834 /// source module. 835 bool ModuleLinker::linkAliasProto(GlobalAlias *SGA) { 836 GlobalValue *DGV = getLinkedToGlobal(SGA); 837 llvm::Optional<GlobalValue::VisibilityTypes> NewVisibility; 838 839 if (DGV) { 840 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; 841 GlobalValue::VisibilityTypes NV; 842 bool LinkFromSrc = false; 843 if (getLinkageResult(DGV, SGA, NewLinkage, NV, LinkFromSrc)) 844 return true; 845 NewVisibility = NV; 846 847 if (!LinkFromSrc) { 848 // Set calculated linkage. 849 DGV->setLinkage(NewLinkage); 850 DGV->setVisibility(*NewVisibility); 851 852 // Make sure to remember this mapping. 853 ValueMap[SGA] = ConstantExpr::getBitCast(DGV,TypeMap.get(SGA->getType())); 854 855 // Track the alias from the source module so we don't attempt to remap it. 856 DoNotLinkFromSource.insert(SGA); 857 858 return false; 859 } 860 } 861 862 // If there is no linkage to be performed or we're linking from the source, 863 // bring over SGA. 864 GlobalAlias *NewDA = new GlobalAlias(TypeMap.get(SGA->getType()), 865 SGA->getLinkage(), SGA->getName(), 866 /*aliasee*/0, DstM); 867 copyGVAttributes(NewDA, SGA); 868 if (NewVisibility) 869 NewDA->setVisibility(*NewVisibility); 870 871 if (DGV) { 872 // Any uses of DGV need to change to NewDA, with cast. 873 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDA, DGV->getType())); 874 DGV->eraseFromParent(); 875 } 876 877 ValueMap[SGA] = NewDA; 878 return false; 879 } 880 881 static void getArrayElements(Constant *C, SmallVectorImpl<Constant*> &Dest) { 882 unsigned NumElements = cast<ArrayType>(C->getType())->getNumElements(); 883 884 for (unsigned i = 0; i != NumElements; ++i) 885 Dest.push_back(C->getAggregateElement(i)); 886 } 887 888 void ModuleLinker::linkAppendingVarInit(const AppendingVarInfo &AVI) { 889 // Merge the initializer. 890 SmallVector<Constant*, 16> Elements; 891 getArrayElements(AVI.DstInit, Elements); 892 893 Constant *SrcInit = MapValue(AVI.SrcInit, ValueMap, RF_None, &TypeMap); 894 getArrayElements(SrcInit, Elements); 895 896 ArrayType *NewType = cast<ArrayType>(AVI.NewGV->getType()->getElementType()); 897 AVI.NewGV->setInitializer(ConstantArray::get(NewType, Elements)); 898 } 899 900 /// linkGlobalInits - Update the initializers in the Dest module now that all 901 /// globals that may be referenced are in Dest. 902 void ModuleLinker::linkGlobalInits() { 903 // Loop over all of the globals in the src module, mapping them over as we go 904 for (Module::const_global_iterator I = SrcM->global_begin(), 905 E = SrcM->global_end(); I != E; ++I) { 906 907 // Only process initialized GV's or ones not already in dest. 908 if (!I->hasInitializer() || DoNotLinkFromSource.count(I)) continue; 909 910 // Grab destination global variable. 911 GlobalVariable *DGV = cast<GlobalVariable>(ValueMap[I]); 912 // Figure out what the initializer looks like in the dest module. 913 DGV->setInitializer(MapValue(I->getInitializer(), ValueMap, 914 RF_None, &TypeMap)); 915 } 916 } 917 918 /// linkFunctionBody - Copy the source function over into the dest function and 919 /// fix up references to values. At this point we know that Dest is an external 920 /// function, and that Src is not. 921 void ModuleLinker::linkFunctionBody(Function *Dst, Function *Src) { 922 assert(Src && Dst && Dst->isDeclaration() && !Src->isDeclaration()); 923 924 // Go through and convert function arguments over, remembering the mapping. 925 Function::arg_iterator DI = Dst->arg_begin(); 926 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end(); 927 I != E; ++I, ++DI) { 928 DI->setName(I->getName()); // Copy the name over. 929 930 // Add a mapping to our mapping. 931 ValueMap[I] = DI; 932 } 933 934 if (Mode == Linker::DestroySource) { 935 // Splice the body of the source function into the dest function. 936 Dst->getBasicBlockList().splice(Dst->end(), Src->getBasicBlockList()); 937 938 // At this point, all of the instructions and values of the function are now 939 // copied over. The only problem is that they are still referencing values in 940 // the Source function as operands. Loop through all of the operands of the 941 // functions and patch them up to point to the local versions. 942 for (Function::iterator BB = Dst->begin(), BE = Dst->end(); BB != BE; ++BB) 943 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) 944 RemapInstruction(I, ValueMap, RF_IgnoreMissingEntries, &TypeMap); 945 946 } else { 947 // Clone the body of the function into the dest function. 948 SmallVector<ReturnInst*, 8> Returns; // Ignore returns. 949 CloneFunctionInto(Dst, Src, ValueMap, false, Returns, "", NULL, &TypeMap); 950 } 951 952 // There is no need to map the arguments anymore. 953 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end(); 954 I != E; ++I) 955 ValueMap.erase(I); 956 957 } 958 959 /// linkAliasBodies - Insert all of the aliases in Src into the Dest module. 960 void ModuleLinker::linkAliasBodies() { 961 for (Module::alias_iterator I = SrcM->alias_begin(), E = SrcM->alias_end(); 962 I != E; ++I) { 963 if (DoNotLinkFromSource.count(I)) 964 continue; 965 if (Constant *Aliasee = I->getAliasee()) { 966 GlobalAlias *DA = cast<GlobalAlias>(ValueMap[I]); 967 DA->setAliasee(MapValue(Aliasee, ValueMap, RF_None, &TypeMap)); 968 } 969 } 970 } 971 972 /// linkNamedMDNodes - Insert all of the named MDNodes in Src into the Dest 973 /// module. 974 void ModuleLinker::linkNamedMDNodes() { 975 const NamedMDNode *SrcModFlags = SrcM->getModuleFlagsMetadata(); 976 for (Module::const_named_metadata_iterator I = SrcM->named_metadata_begin(), 977 E = SrcM->named_metadata_end(); I != E; ++I) { 978 // Don't link module flags here. Do them separately. 979 if (&*I == SrcModFlags) continue; 980 NamedMDNode *DestNMD = DstM->getOrInsertNamedMetadata(I->getName()); 981 // Add Src elements into Dest node. 982 for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) 983 DestNMD->addOperand(MapValue(I->getOperand(i), ValueMap, 984 RF_None, &TypeMap)); 985 } 986 } 987 988 /// categorizeModuleFlagNodes - Categorize the module flags according to their 989 /// type: Error, Warning, Override, and Require. 990 bool ModuleLinker:: 991 categorizeModuleFlagNodes(const NamedMDNode *ModFlags, 992 DenseMap<MDString*, MDNode*> &ErrorNode, 993 DenseMap<MDString*, MDNode*> &WarningNode, 994 DenseMap<MDString*, MDNode*> &OverrideNode, 995 DenseMap<MDString*, 996 SmallSetVector<MDNode*, 8> > &RequireNodes, 997 SmallSetVector<MDString*, 16> &SeenIDs) { 998 bool HasErr = false; 999 1000 for (unsigned I = 0, E = ModFlags->getNumOperands(); I != E; ++I) { 1001 MDNode *Op = ModFlags->getOperand(I); 1002 assert(Op->getNumOperands() == 3 && "Invalid module flag metadata!"); 1003 assert(isa<ConstantInt>(Op->getOperand(0)) && 1004 "Module flag's first operand must be an integer!"); 1005 assert(isa<MDString>(Op->getOperand(1)) && 1006 "Module flag's second operand must be an MDString!"); 1007 1008 ConstantInt *Behavior = cast<ConstantInt>(Op->getOperand(0)); 1009 MDString *ID = cast<MDString>(Op->getOperand(1)); 1010 Value *Val = Op->getOperand(2); 1011 switch (Behavior->getZExtValue()) { 1012 default: 1013 assert(false && "Invalid behavior in module flag metadata!"); 1014 break; 1015 case Module::Error: { 1016 MDNode *&ErrNode = ErrorNode[ID]; 1017 if (!ErrNode) ErrNode = Op; 1018 if (ErrNode->getOperand(2) != Val) 1019 HasErr = emitError("linking module flags '" + ID->getString() + 1020 "': IDs have conflicting values"); 1021 break; 1022 } 1023 case Module::Warning: { 1024 MDNode *&WarnNode = WarningNode[ID]; 1025 if (!WarnNode) WarnNode = Op; 1026 if (WarnNode->getOperand(2) != Val) 1027 errs() << "WARNING: linking module flags '" << ID->getString() 1028 << "': IDs have conflicting values"; 1029 break; 1030 } 1031 case Module::Require: RequireNodes[ID].insert(Op); break; 1032 case Module::Override: { 1033 MDNode *&OvrNode = OverrideNode[ID]; 1034 if (!OvrNode) OvrNode = Op; 1035 if (OvrNode->getOperand(2) != Val) 1036 HasErr = emitError("linking module flags '" + ID->getString() + 1037 "': IDs have conflicting override values"); 1038 break; 1039 } 1040 } 1041 1042 SeenIDs.insert(ID); 1043 } 1044 1045 return HasErr; 1046 } 1047 1048 /// linkModuleFlagsMetadata - Merge the linker flags in Src into the Dest 1049 /// module. 1050 bool ModuleLinker::linkModuleFlagsMetadata() { 1051 const NamedMDNode *SrcModFlags = SrcM->getModuleFlagsMetadata(); 1052 if (!SrcModFlags) return false; 1053 1054 NamedMDNode *DstModFlags = DstM->getOrInsertModuleFlagsMetadata(); 1055 1056 // If the destination module doesn't have module flags yet, then just copy 1057 // over the source module's flags. 1058 if (DstModFlags->getNumOperands() == 0) { 1059 for (unsigned I = 0, E = SrcModFlags->getNumOperands(); I != E; ++I) 1060 DstModFlags->addOperand(SrcModFlags->getOperand(I)); 1061 1062 return false; 1063 } 1064 1065 bool HasErr = false; 1066 1067 // Otherwise, we have to merge them based on their behaviors. First, 1068 // categorize all of the nodes in the modules' module flags. If an error or 1069 // warning occurs, then emit the appropriate message(s). 1070 DenseMap<MDString*, MDNode*> ErrorNode; 1071 DenseMap<MDString*, MDNode*> WarningNode; 1072 DenseMap<MDString*, MDNode*> OverrideNode; 1073 DenseMap<MDString*, SmallSetVector<MDNode*, 8> > RequireNodes; 1074 SmallSetVector<MDString*, 16> SeenIDs; 1075 1076 HasErr |= categorizeModuleFlagNodes(SrcModFlags, ErrorNode, WarningNode, 1077 OverrideNode, RequireNodes, SeenIDs); 1078 HasErr |= categorizeModuleFlagNodes(DstModFlags, ErrorNode, WarningNode, 1079 OverrideNode, RequireNodes, SeenIDs); 1080 1081 // Check that there isn't both an error and warning node for a flag. 1082 for (SmallSetVector<MDString*, 16>::iterator 1083 I = SeenIDs.begin(), E = SeenIDs.end(); I != E; ++I) { 1084 MDString *ID = *I; 1085 if (ErrorNode[ID] && WarningNode[ID]) 1086 HasErr = emitError("linking module flags '" + ID->getString() + 1087 "': IDs have conflicting behaviors"); 1088 } 1089 1090 // Early exit if we had an error. 1091 if (HasErr) return true; 1092 1093 // Get the destination's module flags ready for new operands. 1094 DstModFlags->dropAllReferences(); 1095 1096 // Add all of the module flags to the destination module. 1097 DenseMap<MDString*, SmallVector<MDNode*, 4> > AddedNodes; 1098 for (SmallSetVector<MDString*, 16>::iterator 1099 I = SeenIDs.begin(), E = SeenIDs.end(); I != E; ++I) { 1100 MDString *ID = *I; 1101 if (OverrideNode[ID]) { 1102 DstModFlags->addOperand(OverrideNode[ID]); 1103 AddedNodes[ID].push_back(OverrideNode[ID]); 1104 } else if (ErrorNode[ID]) { 1105 DstModFlags->addOperand(ErrorNode[ID]); 1106 AddedNodes[ID].push_back(ErrorNode[ID]); 1107 } else if (WarningNode[ID]) { 1108 DstModFlags->addOperand(WarningNode[ID]); 1109 AddedNodes[ID].push_back(WarningNode[ID]); 1110 } 1111 1112 for (SmallSetVector<MDNode*, 8>::iterator 1113 II = RequireNodes[ID].begin(), IE = RequireNodes[ID].end(); 1114 II != IE; ++II) 1115 DstModFlags->addOperand(*II); 1116 } 1117 1118 // Now check that all of the requirements have been satisfied. 1119 for (SmallSetVector<MDString*, 16>::iterator 1120 I = SeenIDs.begin(), E = SeenIDs.end(); I != E; ++I) { 1121 MDString *ID = *I; 1122 SmallSetVector<MDNode*, 8> &Set = RequireNodes[ID]; 1123 1124 for (SmallSetVector<MDNode*, 8>::iterator 1125 II = Set.begin(), IE = Set.end(); II != IE; ++II) { 1126 MDNode *Node = *II; 1127 assert(isa<MDNode>(Node->getOperand(2)) && 1128 "Module flag's third operand must be an MDNode!"); 1129 MDNode *Val = cast<MDNode>(Node->getOperand(2)); 1130 1131 MDString *ReqID = cast<MDString>(Val->getOperand(0)); 1132 Value *ReqVal = Val->getOperand(1); 1133 1134 bool HasValue = false; 1135 for (SmallVectorImpl<MDNode*>::iterator 1136 RI = AddedNodes[ReqID].begin(), RE = AddedNodes[ReqID].end(); 1137 RI != RE; ++RI) { 1138 MDNode *ReqNode = *RI; 1139 if (ReqNode->getOperand(2) == ReqVal) { 1140 HasValue = true; 1141 break; 1142 } 1143 } 1144 1145 if (!HasValue) 1146 HasErr = emitError("linking module flags '" + ReqID->getString() + 1147 "': does not have the required value"); 1148 } 1149 } 1150 1151 return HasErr; 1152 } 1153 1154 bool ModuleLinker::run() { 1155 assert(DstM && "Null destination module"); 1156 assert(SrcM && "Null source module"); 1157 1158 // Inherit the target data from the source module if the destination module 1159 // doesn't have one already. 1160 if (DstM->getDataLayout().empty() && !SrcM->getDataLayout().empty()) 1161 DstM->setDataLayout(SrcM->getDataLayout()); 1162 1163 // Copy the target triple from the source to dest if the dest's is empty. 1164 if (DstM->getTargetTriple().empty() && !SrcM->getTargetTriple().empty()) 1165 DstM->setTargetTriple(SrcM->getTargetTriple()); 1166 1167 if (!SrcM->getDataLayout().empty() && !DstM->getDataLayout().empty() && 1168 SrcM->getDataLayout() != DstM->getDataLayout()) 1169 errs() << "WARNING: Linking two modules of different data layouts!\n"; 1170 if (!SrcM->getTargetTriple().empty() && 1171 DstM->getTargetTriple() != SrcM->getTargetTriple()) { 1172 errs() << "WARNING: Linking two modules of different target triples: "; 1173 if (!SrcM->getModuleIdentifier().empty()) 1174 errs() << SrcM->getModuleIdentifier() << ": "; 1175 errs() << "'" << SrcM->getTargetTriple() << "' and '" 1176 << DstM->getTargetTriple() << "'\n"; 1177 } 1178 1179 // Append the module inline asm string. 1180 if (!SrcM->getModuleInlineAsm().empty()) { 1181 if (DstM->getModuleInlineAsm().empty()) 1182 DstM->setModuleInlineAsm(SrcM->getModuleInlineAsm()); 1183 else 1184 DstM->setModuleInlineAsm(DstM->getModuleInlineAsm()+"\n"+ 1185 SrcM->getModuleInlineAsm()); 1186 } 1187 1188 // Update the destination module's dependent libraries list with the libraries 1189 // from the source module. There's no opportunity for duplicates here as the 1190 // Module ensures that duplicate insertions are discarded. 1191 for (Module::lib_iterator SI = SrcM->lib_begin(), SE = SrcM->lib_end(); 1192 SI != SE; ++SI) 1193 DstM->addLibrary(*SI); 1194 1195 // If the source library's module id is in the dependent library list of the 1196 // destination library, remove it since that module is now linked in. 1197 StringRef ModuleId = SrcM->getModuleIdentifier(); 1198 if (!ModuleId.empty()) 1199 DstM->removeLibrary(sys::path::stem(ModuleId)); 1200 1201 // Loop over all of the linked values to compute type mappings. 1202 computeTypeMapping(); 1203 1204 // Insert all of the globals in src into the DstM module... without linking 1205 // initializers (which could refer to functions not yet mapped over). 1206 for (Module::global_iterator I = SrcM->global_begin(), 1207 E = SrcM->global_end(); I != E; ++I) 1208 if (linkGlobalProto(I)) 1209 return true; 1210 1211 // Link the functions together between the two modules, without doing function 1212 // bodies... this just adds external function prototypes to the DstM 1213 // function... We do this so that when we begin processing function bodies, 1214 // all of the global values that may be referenced are available in our 1215 // ValueMap. 1216 for (Module::iterator I = SrcM->begin(), E = SrcM->end(); I != E; ++I) 1217 if (linkFunctionProto(I)) 1218 return true; 1219 1220 // If there were any aliases, link them now. 1221 for (Module::alias_iterator I = SrcM->alias_begin(), 1222 E = SrcM->alias_end(); I != E; ++I) 1223 if (linkAliasProto(I)) 1224 return true; 1225 1226 for (unsigned i = 0, e = AppendingVars.size(); i != e; ++i) 1227 linkAppendingVarInit(AppendingVars[i]); 1228 1229 // Update the initializers in the DstM module now that all globals that may 1230 // be referenced are in DstM. 1231 linkGlobalInits(); 1232 1233 // Link in the function bodies that are defined in the source module into 1234 // DstM. 1235 for (Module::iterator SF = SrcM->begin(), E = SrcM->end(); SF != E; ++SF) { 1236 // Skip if not linking from source. 1237 if (DoNotLinkFromSource.count(SF)) continue; 1238 1239 // Skip if no body (function is external) or materialize. 1240 if (SF->isDeclaration()) { 1241 if (!SF->isMaterializable()) 1242 continue; 1243 if (SF->Materialize(&ErrorMsg)) 1244 return true; 1245 } 1246 1247 linkFunctionBody(cast<Function>(ValueMap[SF]), SF); 1248 SF->Dematerialize(); 1249 } 1250 1251 // Resolve all uses of aliases with aliasees. 1252 linkAliasBodies(); 1253 1254 // Remap all of the named MDNodes in Src into the DstM module. We do this 1255 // after linking GlobalValues so that MDNodes that reference GlobalValues 1256 // are properly remapped. 1257 linkNamedMDNodes(); 1258 1259 // Merge the module flags into the DstM module. 1260 if (linkModuleFlagsMetadata()) 1261 return true; 1262 1263 // Process vector of lazily linked in functions. 1264 bool LinkedInAnyFunctions; 1265 do { 1266 LinkedInAnyFunctions = false; 1267 1268 for(std::vector<Function*>::iterator I = LazilyLinkFunctions.begin(), 1269 E = LazilyLinkFunctions.end(); I != E; ++I) { 1270 if (!*I) 1271 continue; 1272 1273 Function *SF = *I; 1274 Function *DF = cast<Function>(ValueMap[SF]); 1275 1276 if (!DF->use_empty()) { 1277 1278 // Materialize if necessary. 1279 if (SF->isDeclaration()) { 1280 if (!SF->isMaterializable()) 1281 continue; 1282 if (SF->Materialize(&ErrorMsg)) 1283 return true; 1284 } 1285 1286 // Link in function body. 1287 linkFunctionBody(DF, SF); 1288 SF->Dematerialize(); 1289 1290 // "Remove" from vector by setting the element to 0. 1291 *I = 0; 1292 1293 // Set flag to indicate we may have more functions to lazily link in 1294 // since we linked in a function. 1295 LinkedInAnyFunctions = true; 1296 } 1297 } 1298 } while (LinkedInAnyFunctions); 1299 1300 // Remove any prototypes of functions that were not actually linked in. 1301 for(std::vector<Function*>::iterator I = LazilyLinkFunctions.begin(), 1302 E = LazilyLinkFunctions.end(); I != E; ++I) { 1303 if (!*I) 1304 continue; 1305 1306 Function *SF = *I; 1307 Function *DF = cast<Function>(ValueMap[SF]); 1308 if (DF->use_empty()) 1309 DF->eraseFromParent(); 1310 } 1311 1312 // Now that all of the types from the source are used, resolve any structs 1313 // copied over to the dest that didn't exist there. 1314 TypeMap.linkDefinedTypeBodies(); 1315 1316 return false; 1317 } 1318 1319 //===----------------------------------------------------------------------===// 1320 // LinkModules entrypoint. 1321 //===----------------------------------------------------------------------===// 1322 1323 /// LinkModules - This function links two modules together, with the resulting 1324 /// left module modified to be the composite of the two input modules. If an 1325 /// error occurs, true is returned and ErrorMsg (if not null) is set to indicate 1326 /// the problem. Upon failure, the Dest module could be in a modified state, 1327 /// and shouldn't be relied on to be consistent. 1328 bool Linker::LinkModules(Module *Dest, Module *Src, unsigned Mode, 1329 std::string *ErrorMsg) { 1330 ModuleLinker TheLinker(Dest, Src, Mode); 1331 if (TheLinker.run()) { 1332 if (ErrorMsg) *ErrorMsg = TheLinker.ErrorMsg; 1333 return true; 1334 } 1335 1336 return false; 1337 } 1338