LinkModules.cpp revision 6947f10ec467eb89d606bc96450c35864e1b4f10
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-c/Linker.h" 16#include "llvm/ADT/Optional.h" 17#include "llvm/ADT/SetVector.h" 18#include "llvm/ADT/SmallString.h" 19#include "llvm/IR/Constants.h" 20#include "llvm/IR/Module.h" 21#include "llvm/IR/TypeFinder.h" 22#include "llvm/Support/Debug.h" 23#include "llvm/Support/raw_ostream.h" 24#include "llvm/Transforms/Utils/Cloning.h" 25using namespace llvm; 26 27//===----------------------------------------------------------------------===// 28// TypeMap implementation. 29//===----------------------------------------------------------------------===// 30 31namespace { 32 typedef SmallPtrSet<StructType*, 32> TypeSet; 33 34class TypeMapTy : public ValueMapTypeRemapper { 35 /// MappedTypes - This is a mapping from a source type to a destination type 36 /// to use. 37 DenseMap<Type*, Type*> MappedTypes; 38 39 /// SpeculativeTypes - When checking to see if two subgraphs are isomorphic, 40 /// we speculatively add types to MappedTypes, but keep track of them here in 41 /// case we need to roll back. 42 SmallVector<Type*, 16> SpeculativeTypes; 43 44 /// SrcDefinitionsToResolve - This is a list of non-opaque structs in the 45 /// source module that are mapped to an opaque struct in the destination 46 /// module. 47 SmallVector<StructType*, 16> SrcDefinitionsToResolve; 48 49 /// DstResolvedOpaqueTypes - This is the set of opaque types in the 50 /// destination modules who are getting a body from the source module. 51 SmallPtrSet<StructType*, 16> DstResolvedOpaqueTypes; 52 53public: 54 TypeMapTy(TypeSet &Set) : DstStructTypesSet(Set) {} 55 56 TypeSet &DstStructTypesSet; 57 /// addTypeMapping - Indicate that the specified type in the destination 58 /// module is conceptually equivalent to the specified type in the source 59 /// module. 60 void addTypeMapping(Type *DstTy, Type *SrcTy); 61 62 /// linkDefinedTypeBodies - Produce a body for an opaque type in the dest 63 /// module from a type definition in the source module. 64 void linkDefinedTypeBodies(); 65 66 /// get - Return the mapped type to use for the specified input type from the 67 /// source module. 68 Type *get(Type *SrcTy); 69 70 FunctionType *get(FunctionType *T) {return cast<FunctionType>(get((Type*)T));} 71 72 /// dump - Dump out the type map for debugging purposes. 73 void dump() const { 74 for (DenseMap<Type*, Type*>::const_iterator 75 I = MappedTypes.begin(), E = MappedTypes.end(); I != E; ++I) { 76 dbgs() << "TypeMap: "; 77 I->first->dump(); 78 dbgs() << " => "; 79 I->second->dump(); 80 dbgs() << '\n'; 81 } 82 } 83 84private: 85 Type *getImpl(Type *T); 86 /// remapType - Implement the ValueMapTypeRemapper interface. 87 Type *remapType(Type *SrcTy) { 88 return get(SrcTy); 89 } 90 91 bool areTypesIsomorphic(Type *DstTy, Type *SrcTy); 92}; 93} 94 95void TypeMapTy::addTypeMapping(Type *DstTy, Type *SrcTy) { 96 Type *&Entry = MappedTypes[SrcTy]; 97 if (Entry) return; 98 99 if (DstTy == SrcTy) { 100 Entry = DstTy; 101 return; 102 } 103 104 // Check to see if these types are recursively isomorphic and establish a 105 // mapping between them if so. 106 if (!areTypesIsomorphic(DstTy, SrcTy)) { 107 // Oops, they aren't isomorphic. Just discard this request by rolling out 108 // any speculative mappings we've established. 109 for (unsigned i = 0, e = SpeculativeTypes.size(); i != e; ++i) 110 MappedTypes.erase(SpeculativeTypes[i]); 111 } 112 SpeculativeTypes.clear(); 113} 114 115/// areTypesIsomorphic - Recursively walk this pair of types, returning true 116/// if they are isomorphic, false if they are not. 117bool TypeMapTy::areTypesIsomorphic(Type *DstTy, Type *SrcTy) { 118 // Two types with differing kinds are clearly not isomorphic. 119 if (DstTy->getTypeID() != SrcTy->getTypeID()) return false; 120 121 // If we have an entry in the MappedTypes table, then we have our answer. 122 Type *&Entry = MappedTypes[SrcTy]; 123 if (Entry) 124 return Entry == DstTy; 125 126 // Two identical types are clearly isomorphic. Remember this 127 // non-speculatively. 128 if (DstTy == SrcTy) { 129 Entry = DstTy; 130 return true; 131 } 132 133 // Okay, we have two types with identical kinds that we haven't seen before. 134 135 // If this is an opaque struct type, special case it. 136 if (StructType *SSTy = dyn_cast<StructType>(SrcTy)) { 137 // Mapping an opaque type to any struct, just keep the dest struct. 138 if (SSTy->isOpaque()) { 139 Entry = DstTy; 140 SpeculativeTypes.push_back(SrcTy); 141 return true; 142 } 143 144 // Mapping a non-opaque source type to an opaque dest. If this is the first 145 // type that we're mapping onto this destination type then we succeed. Keep 146 // the dest, but fill it in later. This doesn't need to be speculative. If 147 // this is the second (different) type that we're trying to map onto the 148 // same opaque type then we fail. 149 if (cast<StructType>(DstTy)->isOpaque()) { 150 // We can only map one source type onto the opaque destination type. 151 if (!DstResolvedOpaqueTypes.insert(cast<StructType>(DstTy))) 152 return false; 153 SrcDefinitionsToResolve.push_back(SSTy); 154 Entry = DstTy; 155 return true; 156 } 157 } 158 159 // If the number of subtypes disagree between the two types, then we fail. 160 if (SrcTy->getNumContainedTypes() != DstTy->getNumContainedTypes()) 161 return false; 162 163 // Fail if any of the extra properties (e.g. array size) of the type disagree. 164 if (isa<IntegerType>(DstTy)) 165 return false; // bitwidth disagrees. 166 if (PointerType *PT = dyn_cast<PointerType>(DstTy)) { 167 if (PT->getAddressSpace() != cast<PointerType>(SrcTy)->getAddressSpace()) 168 return false; 169 170 } else if (FunctionType *FT = dyn_cast<FunctionType>(DstTy)) { 171 if (FT->isVarArg() != cast<FunctionType>(SrcTy)->isVarArg()) 172 return false; 173 } else if (StructType *DSTy = dyn_cast<StructType>(DstTy)) { 174 StructType *SSTy = cast<StructType>(SrcTy); 175 if (DSTy->isLiteral() != SSTy->isLiteral() || 176 DSTy->isPacked() != SSTy->isPacked()) 177 return false; 178 } else if (ArrayType *DATy = dyn_cast<ArrayType>(DstTy)) { 179 if (DATy->getNumElements() != cast<ArrayType>(SrcTy)->getNumElements()) 180 return false; 181 } else if (VectorType *DVTy = dyn_cast<VectorType>(DstTy)) { 182 if (DVTy->getNumElements() != cast<VectorType>(SrcTy)->getNumElements()) 183 return false; 184 } 185 186 // Otherwise, we speculate that these two types will line up and recursively 187 // check the subelements. 188 Entry = DstTy; 189 SpeculativeTypes.push_back(SrcTy); 190 191 for (unsigned i = 0, e = SrcTy->getNumContainedTypes(); i != e; ++i) 192 if (!areTypesIsomorphic(DstTy->getContainedType(i), 193 SrcTy->getContainedType(i))) 194 return false; 195 196 // If everything seems to have lined up, then everything is great. 197 return true; 198} 199 200/// linkDefinedTypeBodies - Produce a body for an opaque type in the dest 201/// module from a type definition in the source module. 202void TypeMapTy::linkDefinedTypeBodies() { 203 SmallVector<Type*, 16> Elements; 204 SmallString<16> TmpName; 205 206 // Note that processing entries in this loop (calling 'get') can add new 207 // entries to the SrcDefinitionsToResolve vector. 208 while (!SrcDefinitionsToResolve.empty()) { 209 StructType *SrcSTy = SrcDefinitionsToResolve.pop_back_val(); 210 StructType *DstSTy = cast<StructType>(MappedTypes[SrcSTy]); 211 212 // TypeMap is a many-to-one mapping, if there were multiple types that 213 // provide a body for DstSTy then previous iterations of this loop may have 214 // already handled it. Just ignore this case. 215 if (!DstSTy->isOpaque()) continue; 216 assert(!SrcSTy->isOpaque() && "Not resolving a definition?"); 217 218 // Map the body of the source type over to a new body for the dest type. 219 Elements.resize(SrcSTy->getNumElements()); 220 for (unsigned i = 0, e = Elements.size(); i != e; ++i) 221 Elements[i] = getImpl(SrcSTy->getElementType(i)); 222 223 DstSTy->setBody(Elements, SrcSTy->isPacked()); 224 225 // If DstSTy has no name or has a longer name than STy, then viciously steal 226 // STy's name. 227 if (!SrcSTy->hasName()) continue; 228 StringRef SrcName = SrcSTy->getName(); 229 230 if (!DstSTy->hasName() || DstSTy->getName().size() > SrcName.size()) { 231 TmpName.insert(TmpName.end(), SrcName.begin(), SrcName.end()); 232 SrcSTy->setName(""); 233 DstSTy->setName(TmpName.str()); 234 TmpName.clear(); 235 } 236 } 237 238 DstResolvedOpaqueTypes.clear(); 239} 240 241/// get - Return the mapped type to use for the specified input type from the 242/// source module. 243Type *TypeMapTy::get(Type *Ty) { 244 Type *Result = getImpl(Ty); 245 246 // If this caused a reference to any struct type, resolve it before returning. 247 if (!SrcDefinitionsToResolve.empty()) 248 linkDefinedTypeBodies(); 249 return Result; 250} 251 252/// getImpl - This is the recursive version of get(). 253Type *TypeMapTy::getImpl(Type *Ty) { 254 // If we already have an entry for this type, return it. 255 Type **Entry = &MappedTypes[Ty]; 256 if (*Entry) return *Entry; 257 258 // If this is not a named struct type, then just map all of the elements and 259 // then rebuild the type from inside out. 260 if (!isa<StructType>(Ty) || cast<StructType>(Ty)->isLiteral()) { 261 // If there are no element types to map, then the type is itself. This is 262 // true for the anonymous {} struct, things like 'float', integers, etc. 263 if (Ty->getNumContainedTypes() == 0) 264 return *Entry = Ty; 265 266 // Remap all of the elements, keeping track of whether any of them change. 267 bool AnyChange = false; 268 SmallVector<Type*, 4> ElementTypes; 269 ElementTypes.resize(Ty->getNumContainedTypes()); 270 for (unsigned i = 0, e = Ty->getNumContainedTypes(); i != e; ++i) { 271 ElementTypes[i] = getImpl(Ty->getContainedType(i)); 272 AnyChange |= ElementTypes[i] != Ty->getContainedType(i); 273 } 274 275 // If we found our type while recursively processing stuff, just use it. 276 Entry = &MappedTypes[Ty]; 277 if (*Entry) return *Entry; 278 279 // If all of the element types mapped directly over, then the type is usable 280 // as-is. 281 if (!AnyChange) 282 return *Entry = Ty; 283 284 // Otherwise, rebuild a modified type. 285 switch (Ty->getTypeID()) { 286 default: llvm_unreachable("unknown derived type to remap"); 287 case Type::ArrayTyID: 288 return *Entry = ArrayType::get(ElementTypes[0], 289 cast<ArrayType>(Ty)->getNumElements()); 290 case Type::VectorTyID: 291 return *Entry = VectorType::get(ElementTypes[0], 292 cast<VectorType>(Ty)->getNumElements()); 293 case Type::PointerTyID: 294 return *Entry = PointerType::get(ElementTypes[0], 295 cast<PointerType>(Ty)->getAddressSpace()); 296 case Type::FunctionTyID: 297 return *Entry = FunctionType::get(ElementTypes[0], 298 makeArrayRef(ElementTypes).slice(1), 299 cast<FunctionType>(Ty)->isVarArg()); 300 case Type::StructTyID: 301 // Note that this is only reached for anonymous structs. 302 return *Entry = StructType::get(Ty->getContext(), ElementTypes, 303 cast<StructType>(Ty)->isPacked()); 304 } 305 } 306 307 // Otherwise, this is an unmapped named struct. If the struct can be directly 308 // mapped over, just use it as-is. This happens in a case when the linked-in 309 // module has something like: 310 // %T = type {%T*, i32} 311 // @GV = global %T* null 312 // where T does not exist at all in the destination module. 313 // 314 // The other case we watch for is when the type is not in the destination 315 // module, but that it has to be rebuilt because it refers to something that 316 // is already mapped. For example, if the destination module has: 317 // %A = type { i32 } 318 // and the source module has something like 319 // %A' = type { i32 } 320 // %B = type { %A'* } 321 // @GV = global %B* null 322 // then we want to create a new type: "%B = type { %A*}" and have it take the 323 // pristine "%B" name from the source module. 324 // 325 // To determine which case this is, we have to recursively walk the type graph 326 // speculating that we'll be able to reuse it unmodified. Only if this is 327 // safe would we map the entire thing over. Because this is an optimization, 328 // and is not required for the prettiness of the linked module, we just skip 329 // it and always rebuild a type here. 330 StructType *STy = cast<StructType>(Ty); 331 332 // If the type is opaque, we can just use it directly. 333 if (STy->isOpaque()) { 334 // A named structure type from src module is used. Add it to the Set of 335 // identified structs in the destination module. 336 DstStructTypesSet.insert(STy); 337 return *Entry = STy; 338 } 339 340 // Otherwise we create a new type and resolve its body later. This will be 341 // resolved by the top level of get(). 342 SrcDefinitionsToResolve.push_back(STy); 343 StructType *DTy = StructType::create(STy->getContext()); 344 // A new identified structure type was created. Add it to the set of 345 // identified structs in the destination module. 346 DstStructTypesSet.insert(DTy); 347 DstResolvedOpaqueTypes.insert(DTy); 348 return *Entry = DTy; 349} 350 351//===----------------------------------------------------------------------===// 352// ModuleLinker implementation. 353//===----------------------------------------------------------------------===// 354 355namespace { 356 class ModuleLinker; 357 358 /// ValueMaterializerTy - Creates prototypes for functions that are lazily 359 /// linked on the fly. This speeds up linking for modules with many 360 /// lazily linked functions of which few get used. 361 class ValueMaterializerTy : public ValueMaterializer { 362 TypeMapTy &TypeMap; 363 Module *DstM; 364 std::vector<Function*> &LazilyLinkFunctions; 365 public: 366 ValueMaterializerTy(TypeMapTy &TypeMap, Module *DstM, 367 std::vector<Function*> &LazilyLinkFunctions) : 368 ValueMaterializer(), TypeMap(TypeMap), DstM(DstM), 369 LazilyLinkFunctions(LazilyLinkFunctions) { 370 } 371 372 virtual Value *materializeValueFor(Value *V); 373 }; 374 375 /// ModuleLinker - This is an implementation class for the LinkModules 376 /// function, which is the entrypoint for this file. 377 class ModuleLinker { 378 Module *DstM, *SrcM; 379 380 TypeMapTy TypeMap; 381 ValueMaterializerTy ValMaterializer; 382 383 /// ValueMap - Mapping of values from what they used to be in Src, to what 384 /// they are now in DstM. ValueToValueMapTy is a ValueMap, which involves 385 /// some overhead due to the use of Value handles which the Linker doesn't 386 /// actually need, but this allows us to reuse the ValueMapper code. 387 ValueToValueMapTy ValueMap; 388 389 struct AppendingVarInfo { 390 GlobalVariable *NewGV; // New aggregate global in dest module. 391 Constant *DstInit; // Old initializer from dest module. 392 Constant *SrcInit; // Old initializer from src module. 393 }; 394 395 std::vector<AppendingVarInfo> AppendingVars; 396 397 unsigned Mode; // Mode to treat source module. 398 399 // Set of items not to link in from source. 400 SmallPtrSet<const Value*, 16> DoNotLinkFromSource; 401 402 // Vector of functions to lazily link in. 403 std::vector<Function*> LazilyLinkFunctions; 404 405 public: 406 std::string ErrorMsg; 407 408 ModuleLinker(Module *dstM, TypeSet &Set, Module *srcM, unsigned mode) 409 : DstM(dstM), SrcM(srcM), TypeMap(Set), 410 ValMaterializer(TypeMap, DstM, LazilyLinkFunctions), 411 Mode(mode) { } 412 413 bool run(); 414 415 private: 416 /// emitError - Helper method for setting a message and returning an error 417 /// code. 418 bool emitError(const Twine &Message) { 419 ErrorMsg = Message.str(); 420 return true; 421 } 422 423 /// getLinkageResult - This analyzes the two global values and determines 424 /// what the result will look like in the destination module. 425 bool getLinkageResult(GlobalValue *Dest, const GlobalValue *Src, 426 GlobalValue::LinkageTypes <, 427 GlobalValue::VisibilityTypes &Vis, 428 bool &LinkFromSrc); 429 430 /// getLinkedToGlobal - Given a global in the source module, return the 431 /// global in the destination module that is being linked to, if any. 432 GlobalValue *getLinkedToGlobal(GlobalValue *SrcGV) { 433 // If the source has no name it can't link. If it has local linkage, 434 // there is no name match-up going on. 435 if (!SrcGV->hasName() || SrcGV->hasLocalLinkage()) 436 return 0; 437 438 // Otherwise see if we have a match in the destination module's symtab. 439 GlobalValue *DGV = DstM->getNamedValue(SrcGV->getName()); 440 if (DGV == 0) return 0; 441 442 // If we found a global with the same name in the dest module, but it has 443 // internal linkage, we are really not doing any linkage here. 444 if (DGV->hasLocalLinkage()) 445 return 0; 446 447 // Otherwise, we do in fact link to the destination global. 448 return DGV; 449 } 450 451 void computeTypeMapping(); 452 453 bool linkAppendingVarProto(GlobalVariable *DstGV, GlobalVariable *SrcGV); 454 bool linkGlobalProto(GlobalVariable *SrcGV); 455 bool linkFunctionProto(Function *SrcF); 456 bool linkAliasProto(GlobalAlias *SrcA); 457 bool linkModuleFlagsMetadata(); 458 459 void linkAppendingVarInit(const AppendingVarInfo &AVI); 460 void linkGlobalInits(); 461 void linkFunctionBody(Function *Dst, Function *Src); 462 void linkAliasBodies(); 463 void linkNamedMDNodes(); 464 }; 465} 466 467/// forceRenaming - The LLVM SymbolTable class autorenames globals that conflict 468/// in the symbol table. This is good for all clients except for us. Go 469/// through the trouble to force this back. 470static void forceRenaming(GlobalValue *GV, StringRef Name) { 471 // If the global doesn't force its name or if it already has the right name, 472 // there is nothing for us to do. 473 if (GV->hasLocalLinkage() || GV->getName() == Name) 474 return; 475 476 Module *M = GV->getParent(); 477 478 // If there is a conflict, rename the conflict. 479 if (GlobalValue *ConflictGV = M->getNamedValue(Name)) { 480 GV->takeName(ConflictGV); 481 ConflictGV->setName(Name); // This will cause ConflictGV to get renamed 482 assert(ConflictGV->getName() != Name && "forceRenaming didn't work"); 483 } else { 484 GV->setName(Name); // Force the name back 485 } 486} 487 488/// copyGVAttributes - copy additional attributes (those not needed to construct 489/// a GlobalValue) from the SrcGV to the DestGV. 490static void copyGVAttributes(GlobalValue *DestGV, const GlobalValue *SrcGV) { 491 // Use the maximum alignment, rather than just copying the alignment of SrcGV. 492 unsigned Alignment = std::max(DestGV->getAlignment(), SrcGV->getAlignment()); 493 DestGV->copyAttributesFrom(SrcGV); 494 DestGV->setAlignment(Alignment); 495 496 forceRenaming(DestGV, SrcGV->getName()); 497} 498 499static bool isLessConstraining(GlobalValue::VisibilityTypes a, 500 GlobalValue::VisibilityTypes b) { 501 if (a == GlobalValue::HiddenVisibility) 502 return false; 503 if (b == GlobalValue::HiddenVisibility) 504 return true; 505 if (a == GlobalValue::ProtectedVisibility) 506 return false; 507 if (b == GlobalValue::ProtectedVisibility) 508 return true; 509 return false; 510} 511 512Value *ValueMaterializerTy::materializeValueFor(Value *V) { 513 Function *SF = dyn_cast<Function>(V); 514 if (!SF) 515 return NULL; 516 517 Function *DF = Function::Create(TypeMap.get(SF->getFunctionType()), 518 SF->getLinkage(), SF->getName(), DstM); 519 copyGVAttributes(DF, SF); 520 521 LazilyLinkFunctions.push_back(SF); 522 return DF; 523} 524 525 526/// getLinkageResult - This analyzes the two global values and determines what 527/// the result will look like in the destination module. In particular, it 528/// computes the resultant linkage type and visibility, computes whether the 529/// global in the source should be copied over to the destination (replacing 530/// the existing one), and computes whether this linkage is an error or not. 531bool ModuleLinker::getLinkageResult(GlobalValue *Dest, const GlobalValue *Src, 532 GlobalValue::LinkageTypes <, 533 GlobalValue::VisibilityTypes &Vis, 534 bool &LinkFromSrc) { 535 assert(Dest && "Must have two globals being queried"); 536 assert(!Src->hasLocalLinkage() && 537 "If Src has internal linkage, Dest shouldn't be set!"); 538 539 bool SrcIsDeclaration = Src->isDeclaration() && !Src->isMaterializable(); 540 bool DestIsDeclaration = Dest->isDeclaration(); 541 542 if (SrcIsDeclaration) { 543 // If Src is external or if both Src & Dest are external.. Just link the 544 // external globals, we aren't adding anything. 545 if (Src->hasDLLImportLinkage()) { 546 // If one of GVs has DLLImport linkage, result should be dllimport'ed. 547 if (DestIsDeclaration) { 548 LinkFromSrc = true; 549 LT = Src->getLinkage(); 550 } 551 } else if (Dest->hasExternalWeakLinkage()) { 552 // If the Dest is weak, use the source linkage. 553 LinkFromSrc = true; 554 LT = Src->getLinkage(); 555 } else { 556 LinkFromSrc = false; 557 LT = Dest->getLinkage(); 558 } 559 } else if (DestIsDeclaration && !Dest->hasDLLImportLinkage()) { 560 // If Dest is external but Src is not: 561 LinkFromSrc = true; 562 LT = Src->getLinkage(); 563 } else if (Src->isWeakForLinker()) { 564 // At this point we know that Dest has LinkOnce, External*, Weak, Common, 565 // or DLL* linkage. 566 if (Dest->hasExternalWeakLinkage() || 567 Dest->hasAvailableExternallyLinkage() || 568 (Dest->hasLinkOnceLinkage() && 569 (Src->hasWeakLinkage() || Src->hasCommonLinkage()))) { 570 LinkFromSrc = true; 571 LT = Src->getLinkage(); 572 } else { 573 LinkFromSrc = false; 574 LT = Dest->getLinkage(); 575 } 576 } else if (Dest->isWeakForLinker()) { 577 // At this point we know that Src has External* or DLL* linkage. 578 if (Src->hasExternalWeakLinkage()) { 579 LinkFromSrc = false; 580 LT = Dest->getLinkage(); 581 } else { 582 LinkFromSrc = true; 583 LT = GlobalValue::ExternalLinkage; 584 } 585 } else { 586 assert((Dest->hasExternalLinkage() || Dest->hasDLLImportLinkage() || 587 Dest->hasDLLExportLinkage() || Dest->hasExternalWeakLinkage()) && 588 (Src->hasExternalLinkage() || Src->hasDLLImportLinkage() || 589 Src->hasDLLExportLinkage() || Src->hasExternalWeakLinkage()) && 590 "Unexpected linkage type!"); 591 return emitError("Linking globals named '" + Src->getName() + 592 "': symbol multiply defined!"); 593 } 594 595 // Compute the visibility. We follow the rules in the System V Application 596 // Binary Interface. 597 Vis = isLessConstraining(Src->getVisibility(), Dest->getVisibility()) ? 598 Dest->getVisibility() : Src->getVisibility(); 599 return false; 600} 601 602/// computeTypeMapping - Loop over all of the linked values to compute type 603/// mappings. For example, if we link "extern Foo *x" and "Foo *x = NULL", then 604/// we have two struct types 'Foo' but one got renamed when the module was 605/// loaded into the same LLVMContext. 606void ModuleLinker::computeTypeMapping() { 607 // Incorporate globals. 608 for (Module::global_iterator I = SrcM->global_begin(), 609 E = SrcM->global_end(); I != E; ++I) { 610 GlobalValue *DGV = getLinkedToGlobal(I); 611 if (DGV == 0) continue; 612 613 if (!DGV->hasAppendingLinkage() || !I->hasAppendingLinkage()) { 614 TypeMap.addTypeMapping(DGV->getType(), I->getType()); 615 continue; 616 } 617 618 // Unify the element type of appending arrays. 619 ArrayType *DAT = cast<ArrayType>(DGV->getType()->getElementType()); 620 ArrayType *SAT = cast<ArrayType>(I->getType()->getElementType()); 621 TypeMap.addTypeMapping(DAT->getElementType(), SAT->getElementType()); 622 } 623 624 // Incorporate functions. 625 for (Module::iterator I = SrcM->begin(), E = SrcM->end(); I != E; ++I) { 626 if (GlobalValue *DGV = getLinkedToGlobal(I)) 627 TypeMap.addTypeMapping(DGV->getType(), I->getType()); 628 } 629 630 // Incorporate types by name, scanning all the types in the source module. 631 // At this point, the destination module may have a type "%foo = { i32 }" for 632 // example. When the source module got loaded into the same LLVMContext, if 633 // it had the same type, it would have been renamed to "%foo.42 = { i32 }". 634 TypeFinder SrcStructTypes; 635 SrcStructTypes.run(*SrcM, true); 636 SmallPtrSet<StructType*, 32> SrcStructTypesSet(SrcStructTypes.begin(), 637 SrcStructTypes.end()); 638 639 for (unsigned i = 0, e = SrcStructTypes.size(); i != e; ++i) { 640 StructType *ST = SrcStructTypes[i]; 641 if (!ST->hasName()) continue; 642 643 // Check to see if there is a dot in the name followed by a digit. 644 size_t DotPos = ST->getName().rfind('.'); 645 if (DotPos == 0 || DotPos == StringRef::npos || 646 ST->getName().back() == '.' || 647 !isdigit(static_cast<unsigned char>(ST->getName()[DotPos+1]))) 648 continue; 649 650 // Check to see if the destination module has a struct with the prefix name. 651 if (StructType *DST = DstM->getTypeByName(ST->getName().substr(0, DotPos))) 652 // Don't use it if this actually came from the source module. They're in 653 // the same LLVMContext after all. Also don't use it unless the type is 654 // actually used in the destination module. This can happen in situations 655 // like this: 656 // 657 // Module A Module B 658 // -------- -------- 659 // %Z = type { %A } %B = type { %C.1 } 660 // %A = type { %B.1, [7 x i8] } %C.1 = type { i8* } 661 // %B.1 = type { %C } %A.2 = type { %B.3, [5 x i8] } 662 // %C = type { i8* } %B.3 = type { %C.1 } 663 // 664 // When we link Module B with Module A, the '%B' in Module B is 665 // used. However, that would then use '%C.1'. But when we process '%C.1', 666 // we prefer to take the '%C' version. So we are then left with both 667 // '%C.1' and '%C' being used for the same types. This leads to some 668 // variables using one type and some using the other. 669 if (!SrcStructTypesSet.count(DST) && TypeMap.DstStructTypesSet.count(DST)) 670 TypeMap.addTypeMapping(DST, ST); 671 } 672 673 // Don't bother incorporating aliases, they aren't generally typed well. 674 675 // Now that we have discovered all of the type equivalences, get a body for 676 // any 'opaque' types in the dest module that are now resolved. 677 TypeMap.linkDefinedTypeBodies(); 678} 679 680/// linkAppendingVarProto - If there were any appending global variables, link 681/// them together now. Return true on error. 682bool ModuleLinker::linkAppendingVarProto(GlobalVariable *DstGV, 683 GlobalVariable *SrcGV) { 684 685 if (!SrcGV->hasAppendingLinkage() || !DstGV->hasAppendingLinkage()) 686 return emitError("Linking globals named '" + SrcGV->getName() + 687 "': can only link appending global with another appending global!"); 688 689 ArrayType *DstTy = cast<ArrayType>(DstGV->getType()->getElementType()); 690 ArrayType *SrcTy = 691 cast<ArrayType>(TypeMap.get(SrcGV->getType()->getElementType())); 692 Type *EltTy = DstTy->getElementType(); 693 694 // Check to see that they two arrays agree on type. 695 if (EltTy != SrcTy->getElementType()) 696 return emitError("Appending variables with different element types!"); 697 if (DstGV->isConstant() != SrcGV->isConstant()) 698 return emitError("Appending variables linked with different const'ness!"); 699 700 if (DstGV->getAlignment() != SrcGV->getAlignment()) 701 return emitError( 702 "Appending variables with different alignment need to be linked!"); 703 704 if (DstGV->getVisibility() != SrcGV->getVisibility()) 705 return emitError( 706 "Appending variables with different visibility need to be linked!"); 707 708 if (DstGV->getSection() != SrcGV->getSection()) 709 return emitError( 710 "Appending variables with different section name need to be linked!"); 711 712 uint64_t NewSize = DstTy->getNumElements() + SrcTy->getNumElements(); 713 ArrayType *NewType = ArrayType::get(EltTy, NewSize); 714 715 // Create the new global variable. 716 GlobalVariable *NG = 717 new GlobalVariable(*DstGV->getParent(), NewType, SrcGV->isConstant(), 718 DstGV->getLinkage(), /*init*/0, /*name*/"", DstGV, 719 DstGV->getThreadLocalMode(), 720 DstGV->getType()->getAddressSpace()); 721 722 // Propagate alignment, visibility and section info. 723 copyGVAttributes(NG, DstGV); 724 725 AppendingVarInfo AVI; 726 AVI.NewGV = NG; 727 AVI.DstInit = DstGV->getInitializer(); 728 AVI.SrcInit = SrcGV->getInitializer(); 729 AppendingVars.push_back(AVI); 730 731 // Replace any uses of the two global variables with uses of the new 732 // global. 733 ValueMap[SrcGV] = ConstantExpr::getBitCast(NG, TypeMap.get(SrcGV->getType())); 734 735 DstGV->replaceAllUsesWith(ConstantExpr::getBitCast(NG, DstGV->getType())); 736 DstGV->eraseFromParent(); 737 738 // Track the source variable so we don't try to link it. 739 DoNotLinkFromSource.insert(SrcGV); 740 741 return false; 742} 743 744/// linkGlobalProto - Loop through the global variables in the src module and 745/// merge them into the dest module. 746bool ModuleLinker::linkGlobalProto(GlobalVariable *SGV) { 747 GlobalValue *DGV = getLinkedToGlobal(SGV); 748 llvm::Optional<GlobalValue::VisibilityTypes> NewVisibility; 749 bool HasUnnamedAddr = SGV->hasUnnamedAddr(); 750 751 if (DGV) { 752 // Concatenation of appending linkage variables is magic and handled later. 753 if (DGV->hasAppendingLinkage() || SGV->hasAppendingLinkage()) 754 return linkAppendingVarProto(cast<GlobalVariable>(DGV), SGV); 755 756 // Determine whether linkage of these two globals follows the source 757 // module's definition or the destination module's definition. 758 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; 759 GlobalValue::VisibilityTypes NV; 760 bool LinkFromSrc = false; 761 if (getLinkageResult(DGV, SGV, NewLinkage, NV, LinkFromSrc)) 762 return true; 763 NewVisibility = NV; 764 HasUnnamedAddr = HasUnnamedAddr && DGV->hasUnnamedAddr(); 765 766 // If we're not linking from the source, then keep the definition that we 767 // have. 768 if (!LinkFromSrc) { 769 // Special case for const propagation. 770 if (GlobalVariable *DGVar = dyn_cast<GlobalVariable>(DGV)) 771 if (DGVar->isDeclaration() && SGV->isConstant() && !DGVar->isConstant()) 772 DGVar->setConstant(true); 773 774 // Set calculated linkage, visibility and unnamed_addr. 775 DGV->setLinkage(NewLinkage); 776 DGV->setVisibility(*NewVisibility); 777 DGV->setUnnamedAddr(HasUnnamedAddr); 778 779 // Make sure to remember this mapping. 780 ValueMap[SGV] = ConstantExpr::getBitCast(DGV,TypeMap.get(SGV->getType())); 781 782 // Track the source global so that we don't attempt to copy it over when 783 // processing global initializers. 784 DoNotLinkFromSource.insert(SGV); 785 786 return false; 787 } 788 } 789 790 // No linking to be performed or linking from the source: simply create an 791 // identical version of the symbol over in the dest module... the 792 // initializer will be filled in later by LinkGlobalInits. 793 GlobalVariable *NewDGV = 794 new GlobalVariable(*DstM, TypeMap.get(SGV->getType()->getElementType()), 795 SGV->isConstant(), SGV->getLinkage(), /*init*/0, 796 SGV->getName(), /*insertbefore*/0, 797 SGV->getThreadLocalMode(), 798 SGV->getType()->getAddressSpace()); 799 // Propagate alignment, visibility and section info. 800 copyGVAttributes(NewDGV, SGV); 801 if (NewVisibility) 802 NewDGV->setVisibility(*NewVisibility); 803 NewDGV->setUnnamedAddr(HasUnnamedAddr); 804 805 if (DGV) { 806 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDGV, DGV->getType())); 807 DGV->eraseFromParent(); 808 } 809 810 // Make sure to remember this mapping. 811 ValueMap[SGV] = NewDGV; 812 return false; 813} 814 815/// linkFunctionProto - Link the function in the source module into the 816/// destination module if needed, setting up mapping information. 817bool ModuleLinker::linkFunctionProto(Function *SF) { 818 GlobalValue *DGV = getLinkedToGlobal(SF); 819 llvm::Optional<GlobalValue::VisibilityTypes> NewVisibility; 820 bool HasUnnamedAddr = SF->hasUnnamedAddr(); 821 822 if (DGV) { 823 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; 824 bool LinkFromSrc = false; 825 GlobalValue::VisibilityTypes NV; 826 if (getLinkageResult(DGV, SF, NewLinkage, NV, LinkFromSrc)) 827 return true; 828 NewVisibility = NV; 829 HasUnnamedAddr = HasUnnamedAddr && DGV->hasUnnamedAddr(); 830 831 if (!LinkFromSrc) { 832 // Set calculated linkage 833 DGV->setLinkage(NewLinkage); 834 DGV->setVisibility(*NewVisibility); 835 DGV->setUnnamedAddr(HasUnnamedAddr); 836 837 // Make sure to remember this mapping. 838 ValueMap[SF] = ConstantExpr::getBitCast(DGV, TypeMap.get(SF->getType())); 839 840 // Track the function from the source module so we don't attempt to remap 841 // it. 842 DoNotLinkFromSource.insert(SF); 843 844 return false; 845 } 846 } 847 848 // If the function is to be lazily linked, don't create it just yet. 849 // The ValueMaterializerTy will deal with creating it if it's used. 850 if (!DGV && (SF->hasLocalLinkage() || SF->hasLinkOnceLinkage() || 851 SF->hasAvailableExternallyLinkage())) { 852 DoNotLinkFromSource.insert(SF); 853 return false; 854 } 855 856 // If there is no linkage to be performed or we are linking from the source, 857 // bring SF over. 858 Function *NewDF = Function::Create(TypeMap.get(SF->getFunctionType()), 859 SF->getLinkage(), SF->getName(), DstM); 860 copyGVAttributes(NewDF, SF); 861 if (NewVisibility) 862 NewDF->setVisibility(*NewVisibility); 863 NewDF->setUnnamedAddr(HasUnnamedAddr); 864 865 if (DGV) { 866 // Any uses of DF need to change to NewDF, with cast. 867 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDF, DGV->getType())); 868 DGV->eraseFromParent(); 869 } 870 871 ValueMap[SF] = NewDF; 872 return false; 873} 874 875/// LinkAliasProto - Set up prototypes for any aliases that come over from the 876/// source module. 877bool ModuleLinker::linkAliasProto(GlobalAlias *SGA) { 878 GlobalValue *DGV = getLinkedToGlobal(SGA); 879 llvm::Optional<GlobalValue::VisibilityTypes> NewVisibility; 880 881 if (DGV) { 882 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; 883 GlobalValue::VisibilityTypes NV; 884 bool LinkFromSrc = false; 885 if (getLinkageResult(DGV, SGA, NewLinkage, NV, LinkFromSrc)) 886 return true; 887 NewVisibility = NV; 888 889 if (!LinkFromSrc) { 890 // Set calculated linkage. 891 DGV->setLinkage(NewLinkage); 892 DGV->setVisibility(*NewVisibility); 893 894 // Make sure to remember this mapping. 895 ValueMap[SGA] = ConstantExpr::getBitCast(DGV,TypeMap.get(SGA->getType())); 896 897 // Track the alias from the source module so we don't attempt to remap it. 898 DoNotLinkFromSource.insert(SGA); 899 900 return false; 901 } 902 } 903 904 // If there is no linkage to be performed or we're linking from the source, 905 // bring over SGA. 906 GlobalAlias *NewDA = new GlobalAlias(TypeMap.get(SGA->getType()), 907 SGA->getLinkage(), SGA->getName(), 908 /*aliasee*/0, DstM); 909 copyGVAttributes(NewDA, SGA); 910 if (NewVisibility) 911 NewDA->setVisibility(*NewVisibility); 912 913 if (DGV) { 914 // Any uses of DGV need to change to NewDA, with cast. 915 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDA, DGV->getType())); 916 DGV->eraseFromParent(); 917 } 918 919 ValueMap[SGA] = NewDA; 920 return false; 921} 922 923static void getArrayElements(Constant *C, SmallVectorImpl<Constant*> &Dest) { 924 unsigned NumElements = cast<ArrayType>(C->getType())->getNumElements(); 925 926 for (unsigned i = 0; i != NumElements; ++i) 927 Dest.push_back(C->getAggregateElement(i)); 928} 929 930void ModuleLinker::linkAppendingVarInit(const AppendingVarInfo &AVI) { 931 // Merge the initializer. 932 SmallVector<Constant*, 16> Elements; 933 getArrayElements(AVI.DstInit, Elements); 934 935 Constant *SrcInit = MapValue(AVI.SrcInit, ValueMap, RF_None, &TypeMap, &ValMaterializer); 936 getArrayElements(SrcInit, Elements); 937 938 ArrayType *NewType = cast<ArrayType>(AVI.NewGV->getType()->getElementType()); 939 AVI.NewGV->setInitializer(ConstantArray::get(NewType, Elements)); 940} 941 942/// linkGlobalInits - Update the initializers in the Dest module now that all 943/// globals that may be referenced are in Dest. 944void ModuleLinker::linkGlobalInits() { 945 // Loop over all of the globals in the src module, mapping them over as we go 946 for (Module::const_global_iterator I = SrcM->global_begin(), 947 E = SrcM->global_end(); I != E; ++I) { 948 949 // Only process initialized GV's or ones not already in dest. 950 if (!I->hasInitializer() || DoNotLinkFromSource.count(I)) continue; 951 952 // Grab destination global variable. 953 GlobalVariable *DGV = cast<GlobalVariable>(ValueMap[I]); 954 // Figure out what the initializer looks like in the dest module. 955 DGV->setInitializer(MapValue(I->getInitializer(), ValueMap, 956 RF_None, &TypeMap, &ValMaterializer)); 957 } 958} 959 960/// linkFunctionBody - Copy the source function over into the dest function and 961/// fix up references to values. At this point we know that Dest is an external 962/// function, and that Src is not. 963void ModuleLinker::linkFunctionBody(Function *Dst, Function *Src) { 964 assert(Src && Dst && Dst->isDeclaration() && !Src->isDeclaration()); 965 966 // Go through and convert function arguments over, remembering the mapping. 967 Function::arg_iterator DI = Dst->arg_begin(); 968 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end(); 969 I != E; ++I, ++DI) { 970 DI->setName(I->getName()); // Copy the name over. 971 972 // Add a mapping to our mapping. 973 ValueMap[I] = DI; 974 } 975 976 if (Mode == Linker::DestroySource) { 977 // Splice the body of the source function into the dest function. 978 Dst->getBasicBlockList().splice(Dst->end(), Src->getBasicBlockList()); 979 980 // At this point, all of the instructions and values of the function are now 981 // copied over. The only problem is that they are still referencing values in 982 // the Source function as operands. Loop through all of the operands of the 983 // functions and patch them up to point to the local versions. 984 for (Function::iterator BB = Dst->begin(), BE = Dst->end(); BB != BE; ++BB) 985 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) 986 RemapInstruction(I, ValueMap, RF_IgnoreMissingEntries, 987 &TypeMap, &ValMaterializer); 988 989 } else { 990 // Clone the body of the function into the dest function. 991 SmallVector<ReturnInst*, 8> Returns; // Ignore returns. 992 CloneFunctionInto(Dst, Src, ValueMap, false, Returns, "", NULL, 993 &TypeMap, &ValMaterializer); 994 } 995 996 // There is no need to map the arguments anymore. 997 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end(); 998 I != E; ++I) 999 ValueMap.erase(I); 1000 1001} 1002 1003/// linkAliasBodies - Insert all of the aliases in Src into the Dest module. 1004void ModuleLinker::linkAliasBodies() { 1005 for (Module::alias_iterator I = SrcM->alias_begin(), E = SrcM->alias_end(); 1006 I != E; ++I) { 1007 if (DoNotLinkFromSource.count(I)) 1008 continue; 1009 if (Constant *Aliasee = I->getAliasee()) { 1010 GlobalAlias *DA = cast<GlobalAlias>(ValueMap[I]); 1011 DA->setAliasee(MapValue(Aliasee, ValueMap, RF_None, 1012 &TypeMap, &ValMaterializer)); 1013 } 1014 } 1015} 1016 1017/// linkNamedMDNodes - Insert all of the named MDNodes in Src into the Dest 1018/// module. 1019void ModuleLinker::linkNamedMDNodes() { 1020 const NamedMDNode *SrcModFlags = SrcM->getModuleFlagsMetadata(); 1021 for (Module::const_named_metadata_iterator I = SrcM->named_metadata_begin(), 1022 E = SrcM->named_metadata_end(); I != E; ++I) { 1023 // Don't link module flags here. Do them separately. 1024 if (&*I == SrcModFlags) continue; 1025 NamedMDNode *DestNMD = DstM->getOrInsertNamedMetadata(I->getName()); 1026 // Add Src elements into Dest node. 1027 for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) 1028 DestNMD->addOperand(MapValue(I->getOperand(i), ValueMap, 1029 RF_None, &TypeMap, &ValMaterializer)); 1030 } 1031} 1032 1033/// linkModuleFlagsMetadata - Merge the linker flags in Src into the Dest 1034/// module. 1035bool ModuleLinker::linkModuleFlagsMetadata() { 1036 // If the source module has no module flags, we are done. 1037 const NamedMDNode *SrcModFlags = SrcM->getModuleFlagsMetadata(); 1038 if (!SrcModFlags) return false; 1039 1040 // If the destination module doesn't have module flags yet, then just copy 1041 // over the source module's flags. 1042 NamedMDNode *DstModFlags = DstM->getOrInsertModuleFlagsMetadata(); 1043 if (DstModFlags->getNumOperands() == 0) { 1044 for (unsigned I = 0, E = SrcModFlags->getNumOperands(); I != E; ++I) 1045 DstModFlags->addOperand(SrcModFlags->getOperand(I)); 1046 1047 return false; 1048 } 1049 1050 // First build a map of the existing module flags and requirements. 1051 DenseMap<MDString*, MDNode*> Flags; 1052 SmallSetVector<MDNode*, 16> Requirements; 1053 for (unsigned I = 0, E = DstModFlags->getNumOperands(); I != E; ++I) { 1054 MDNode *Op = DstModFlags->getOperand(I); 1055 ConstantInt *Behavior = cast<ConstantInt>(Op->getOperand(0)); 1056 MDString *ID = cast<MDString>(Op->getOperand(1)); 1057 1058 if (Behavior->getZExtValue() == Module::Require) { 1059 Requirements.insert(cast<MDNode>(Op->getOperand(2))); 1060 } else { 1061 Flags[ID] = Op; 1062 } 1063 } 1064 1065 // Merge in the flags from the source module, and also collect its set of 1066 // requirements. 1067 bool HasErr = false; 1068 for (unsigned I = 0, E = SrcModFlags->getNumOperands(); I != E; ++I) { 1069 MDNode *SrcOp = SrcModFlags->getOperand(I); 1070 ConstantInt *SrcBehavior = cast<ConstantInt>(SrcOp->getOperand(0)); 1071 MDString *ID = cast<MDString>(SrcOp->getOperand(1)); 1072 MDNode *DstOp = Flags.lookup(ID); 1073 unsigned SrcBehaviorValue = SrcBehavior->getZExtValue(); 1074 1075 // If this is a requirement, add it and continue. 1076 if (SrcBehaviorValue == Module::Require) { 1077 // If the destination module does not already have this requirement, add 1078 // it. 1079 if (Requirements.insert(cast<MDNode>(SrcOp->getOperand(2)))) { 1080 DstModFlags->addOperand(SrcOp); 1081 } 1082 continue; 1083 } 1084 1085 // If there is no existing flag with this ID, just add it. 1086 if (!DstOp) { 1087 Flags[ID] = SrcOp; 1088 DstModFlags->addOperand(SrcOp); 1089 continue; 1090 } 1091 1092 // Otherwise, perform a merge. 1093 ConstantInt *DstBehavior = cast<ConstantInt>(DstOp->getOperand(0)); 1094 unsigned DstBehaviorValue = DstBehavior->getZExtValue(); 1095 1096 // If either flag has override behavior, handle it first. 1097 if (DstBehaviorValue == Module::Override) { 1098 // Diagnose inconsistent flags which both have override behavior. 1099 if (SrcBehaviorValue == Module::Override && 1100 SrcOp->getOperand(2) != DstOp->getOperand(2)) { 1101 HasErr |= emitError("linking module flags '" + ID->getString() + 1102 "': IDs have conflicting override values"); 1103 } 1104 continue; 1105 } else if (SrcBehaviorValue == Module::Override) { 1106 // Update the destination flag to that of the source. 1107 DstOp->replaceOperandWith(0, SrcBehavior); 1108 DstOp->replaceOperandWith(2, SrcOp->getOperand(2)); 1109 continue; 1110 } 1111 1112 // Diagnose inconsistent merge behavior types. 1113 if (SrcBehaviorValue != DstBehaviorValue) { 1114 HasErr |= emitError("linking module flags '" + ID->getString() + 1115 "': IDs have conflicting behaviors"); 1116 continue; 1117 } 1118 1119 // Perform the merge for standard behavior types. 1120 switch (SrcBehaviorValue) { 1121 case Module::Require: 1122 case Module::Override: assert(0 && "not possible"); break; 1123 case Module::Error: { 1124 // Emit an error if the values differ. 1125 if (SrcOp->getOperand(2) != DstOp->getOperand(2)) { 1126 HasErr |= emitError("linking module flags '" + ID->getString() + 1127 "': IDs have conflicting values"); 1128 } 1129 continue; 1130 } 1131 case Module::Warning: { 1132 // Emit a warning if the values differ. 1133 if (SrcOp->getOperand(2) != DstOp->getOperand(2)) { 1134 errs() << "WARNING: linking module flags '" << ID->getString() 1135 << "': IDs have conflicting values"; 1136 } 1137 continue; 1138 } 1139 case Module::Append: { 1140 MDNode *DstValue = cast<MDNode>(DstOp->getOperand(2)); 1141 MDNode *SrcValue = cast<MDNode>(SrcOp->getOperand(2)); 1142 unsigned NumOps = DstValue->getNumOperands() + SrcValue->getNumOperands(); 1143 Value **VP, **Values = VP = new Value*[NumOps]; 1144 for (unsigned i = 0, e = DstValue->getNumOperands(); i != e; ++i, ++VP) 1145 *VP = DstValue->getOperand(i); 1146 for (unsigned i = 0, e = SrcValue->getNumOperands(); i != e; ++i, ++VP) 1147 *VP = SrcValue->getOperand(i); 1148 DstOp->replaceOperandWith(2, MDNode::get(DstM->getContext(), 1149 ArrayRef<Value*>(Values, 1150 NumOps))); 1151 delete[] Values; 1152 break; 1153 } 1154 case Module::AppendUnique: { 1155 SmallSetVector<Value*, 16> Elts; 1156 MDNode *DstValue = cast<MDNode>(DstOp->getOperand(2)); 1157 MDNode *SrcValue = cast<MDNode>(SrcOp->getOperand(2)); 1158 for (unsigned i = 0, e = DstValue->getNumOperands(); i != e; ++i) 1159 Elts.insert(DstValue->getOperand(i)); 1160 for (unsigned i = 0, e = SrcValue->getNumOperands(); i != e; ++i) 1161 Elts.insert(SrcValue->getOperand(i)); 1162 DstOp->replaceOperandWith(2, MDNode::get(DstM->getContext(), 1163 ArrayRef<Value*>(Elts.begin(), 1164 Elts.end()))); 1165 break; 1166 } 1167 } 1168 } 1169 1170 // Check all of the requirements. 1171 for (unsigned I = 0, E = Requirements.size(); I != E; ++I) { 1172 MDNode *Requirement = Requirements[I]; 1173 MDString *Flag = cast<MDString>(Requirement->getOperand(0)); 1174 Value *ReqValue = Requirement->getOperand(1); 1175 1176 MDNode *Op = Flags[Flag]; 1177 if (!Op || Op->getOperand(2) != ReqValue) { 1178 HasErr |= emitError("linking module flags '" + Flag->getString() + 1179 "': does not have the required value"); 1180 continue; 1181 } 1182 } 1183 1184 return HasErr; 1185} 1186 1187bool ModuleLinker::run() { 1188 assert(DstM && "Null destination module"); 1189 assert(SrcM && "Null source module"); 1190 1191 // Inherit the target data from the source module if the destination module 1192 // doesn't have one already. 1193 if (DstM->getDataLayout().empty() && !SrcM->getDataLayout().empty()) 1194 DstM->setDataLayout(SrcM->getDataLayout()); 1195 1196 // Copy the target triple from the source to dest if the dest's is empty. 1197 if (DstM->getTargetTriple().empty() && !SrcM->getTargetTriple().empty()) 1198 DstM->setTargetTriple(SrcM->getTargetTriple()); 1199 1200 if (!SrcM->getDataLayout().empty() && !DstM->getDataLayout().empty() && 1201 SrcM->getDataLayout() != DstM->getDataLayout()) 1202 errs() << "WARNING: Linking two modules of different data layouts!\n"; 1203 if (!SrcM->getTargetTriple().empty() && 1204 DstM->getTargetTriple() != SrcM->getTargetTriple()) { 1205 errs() << "WARNING: Linking two modules of different target triples: "; 1206 if (!SrcM->getModuleIdentifier().empty()) 1207 errs() << SrcM->getModuleIdentifier() << ": "; 1208 errs() << "'" << SrcM->getTargetTriple() << "' and '" 1209 << DstM->getTargetTriple() << "'\n"; 1210 } 1211 1212 // Append the module inline asm string. 1213 if (!SrcM->getModuleInlineAsm().empty()) { 1214 if (DstM->getModuleInlineAsm().empty()) 1215 DstM->setModuleInlineAsm(SrcM->getModuleInlineAsm()); 1216 else 1217 DstM->setModuleInlineAsm(DstM->getModuleInlineAsm()+"\n"+ 1218 SrcM->getModuleInlineAsm()); 1219 } 1220 1221 // Loop over all of the linked values to compute type mappings. 1222 computeTypeMapping(); 1223 1224 // Insert all of the globals in src into the DstM module... without linking 1225 // initializers (which could refer to functions not yet mapped over). 1226 for (Module::global_iterator I = SrcM->global_begin(), 1227 E = SrcM->global_end(); I != E; ++I) 1228 if (linkGlobalProto(I)) 1229 return true; 1230 1231 // Link the functions together between the two modules, without doing function 1232 // bodies... this just adds external function prototypes to the DstM 1233 // function... We do this so that when we begin processing function bodies, 1234 // all of the global values that may be referenced are available in our 1235 // ValueMap. 1236 for (Module::iterator I = SrcM->begin(), E = SrcM->end(); I != E; ++I) 1237 if (linkFunctionProto(I)) 1238 return true; 1239 1240 // If there were any aliases, link them now. 1241 for (Module::alias_iterator I = SrcM->alias_begin(), 1242 E = SrcM->alias_end(); I != E; ++I) 1243 if (linkAliasProto(I)) 1244 return true; 1245 1246 for (unsigned i = 0, e = AppendingVars.size(); i != e; ++i) 1247 linkAppendingVarInit(AppendingVars[i]); 1248 1249 // Update the initializers in the DstM module now that all globals that may 1250 // be referenced are in DstM. 1251 linkGlobalInits(); 1252 1253 // Link in the function bodies that are defined in the source module into 1254 // DstM. 1255 for (Module::iterator SF = SrcM->begin(), E = SrcM->end(); SF != E; ++SF) { 1256 // Skip if not linking from source. 1257 if (DoNotLinkFromSource.count(SF)) continue; 1258 1259 // Skip if no body (function is external) or materialize. 1260 if (SF->isDeclaration()) { 1261 if (!SF->isMaterializable()) 1262 continue; 1263 if (SF->Materialize(&ErrorMsg)) 1264 return true; 1265 } 1266 1267 linkFunctionBody(cast<Function>(ValueMap[SF]), SF); 1268 SF->Dematerialize(); 1269 } 1270 1271 // Resolve all uses of aliases with aliasees. 1272 linkAliasBodies(); 1273 1274 // Remap all of the named MDNodes in Src into the DstM module. We do this 1275 // after linking GlobalValues so that MDNodes that reference GlobalValues 1276 // are properly remapped. 1277 linkNamedMDNodes(); 1278 1279 // Merge the module flags into the DstM module. 1280 if (linkModuleFlagsMetadata()) 1281 return true; 1282 1283 // Process vector of lazily linked in functions. 1284 bool LinkedInAnyFunctions; 1285 do { 1286 LinkedInAnyFunctions = false; 1287 1288 for(std::vector<Function*>::iterator I = LazilyLinkFunctions.begin(), 1289 E = LazilyLinkFunctions.end(); I != E; ++I) { 1290 Function *SF = *I; 1291 if (!SF) 1292 continue; 1293 1294 Function *DF = cast<Function>(ValueMap[SF]); 1295 1296 // Materialize if necessary. 1297 if (SF->isDeclaration()) { 1298 if (!SF->isMaterializable()) 1299 continue; 1300 if (SF->Materialize(&ErrorMsg)) 1301 return true; 1302 } 1303 1304 // Erase from vector *before* the function body is linked - linkFunctionBody could 1305 // invalidate I. 1306 LazilyLinkFunctions.erase(I); 1307 1308 // Link in function body. 1309 linkFunctionBody(DF, SF); 1310 SF->Dematerialize(); 1311 1312 // Set flag to indicate we may have more functions to lazily link in 1313 // since we linked in a function. 1314 LinkedInAnyFunctions = true; 1315 break; 1316 } 1317 } while (LinkedInAnyFunctions); 1318 1319 // Now that all of the types from the source are used, resolve any structs 1320 // copied over to the dest that didn't exist there. 1321 TypeMap.linkDefinedTypeBodies(); 1322 1323 return false; 1324} 1325 1326Linker::Linker(Module *M) : Composite(M) { 1327 TypeFinder StructTypes; 1328 StructTypes.run(*M, true); 1329 IdentifiedStructTypes.insert(StructTypes.begin(), StructTypes.end()); 1330} 1331 1332Linker::~Linker() { 1333} 1334 1335bool Linker::linkInModule(Module *Src, unsigned Mode, std::string *ErrorMsg) { 1336 ModuleLinker TheLinker(Composite, IdentifiedStructTypes, Src, Mode); 1337 if (TheLinker.run()) { 1338 if (ErrorMsg) 1339 *ErrorMsg = TheLinker.ErrorMsg; 1340 return true; 1341 } 1342 return false; 1343} 1344 1345//===----------------------------------------------------------------------===// 1346// LinkModules entrypoint. 1347//===----------------------------------------------------------------------===// 1348 1349/// LinkModules - This function links two modules together, with the resulting 1350/// Dest module modified to be the composite of the two input modules. If an 1351/// error occurs, true is returned and ErrorMsg (if not null) is set to indicate 1352/// the problem. Upon failure, the Dest module could be in a modified state, 1353/// and shouldn't be relied on to be consistent. 1354bool Linker::LinkModules(Module *Dest, Module *Src, unsigned Mode, 1355 std::string *ErrorMsg) { 1356 Linker L(Dest); 1357 return L.linkInModule(Src, Mode, ErrorMsg); 1358} 1359 1360//===----------------------------------------------------------------------===// 1361// C API. 1362//===----------------------------------------------------------------------===// 1363 1364LLVMBool LLVMLinkModules(LLVMModuleRef Dest, LLVMModuleRef Src, 1365 LLVMLinkerMode Mode, char **OutMessages) { 1366 std::string Messages; 1367 LLVMBool Result = Linker::LinkModules(unwrap(Dest), unwrap(Src), 1368 Mode, OutMessages? &Messages : 0); 1369 if (OutMessages) 1370 *OutMessages = strdup(Messages.c_str()); 1371 return Result; 1372} 1373