LinkModules.cpp revision 5d5f2c37d57276c9320dd2677d355d47fa4bc5c4
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" 25#include <cctype> 26using namespace llvm; 27 28//===----------------------------------------------------------------------===// 29// TypeMap implementation. 30//===----------------------------------------------------------------------===// 31 32namespace { 33 typedef SmallPtrSet<StructType*, 32> TypeSet; 34 35class TypeMapTy : public ValueMapTypeRemapper { 36 /// MappedTypes - This is a mapping from a source type to a destination type 37 /// to use. 38 DenseMap<Type*, Type*> MappedTypes; 39 40 /// SpeculativeTypes - When checking to see if two subgraphs are isomorphic, 41 /// we speculatively add types to MappedTypes, but keep track of them here in 42 /// case we need to roll back. 43 SmallVector<Type*, 16> SpeculativeTypes; 44 45 /// SrcDefinitionsToResolve - This is a list of non-opaque structs in the 46 /// source module that are mapped to an opaque struct in the destination 47 /// module. 48 SmallVector<StructType*, 16> SrcDefinitionsToResolve; 49 50 /// DstResolvedOpaqueTypes - This is the set of opaque types in the 51 /// destination modules who are getting a body from the source module. 52 SmallPtrSet<StructType*, 16> DstResolvedOpaqueTypes; 53 54public: 55 TypeMapTy(TypeSet &Set) : DstStructTypesSet(Set) {} 56 57 TypeSet &DstStructTypesSet; 58 /// addTypeMapping - Indicate that the specified type in the destination 59 /// module is conceptually equivalent to the specified type in the source 60 /// module. 61 void addTypeMapping(Type *DstTy, Type *SrcTy); 62 63 /// linkDefinedTypeBodies - Produce a body for an opaque type in the dest 64 /// module from a type definition in the source module. 65 void linkDefinedTypeBodies(); 66 67 /// get - Return the mapped type to use for the specified input type from the 68 /// source module. 69 Type *get(Type *SrcTy); 70 71 FunctionType *get(FunctionType *T) {return cast<FunctionType>(get((Type*)T));} 72 73 /// dump - Dump out the type map for debugging purposes. 74 void dump() const { 75 for (DenseMap<Type*, Type*>::const_iterator 76 I = MappedTypes.begin(), E = MappedTypes.end(); I != E; ++I) { 77 dbgs() << "TypeMap: "; 78 I->first->dump(); 79 dbgs() << " => "; 80 I->second->dump(); 81 dbgs() << '\n'; 82 } 83 } 84 85private: 86 Type *getImpl(Type *T); 87 /// remapType - Implement the ValueMapTypeRemapper interface. 88 Type *remapType(Type *SrcTy) { 89 return get(SrcTy); 90 } 91 92 bool areTypesIsomorphic(Type *DstTy, Type *SrcTy); 93}; 94} 95 96void TypeMapTy::addTypeMapping(Type *DstTy, Type *SrcTy) { 97 Type *&Entry = MappedTypes[SrcTy]; 98 if (Entry) return; 99 100 if (DstTy == SrcTy) { 101 Entry = DstTy; 102 return; 103 } 104 105 // Check to see if these types are recursively isomorphic and establish a 106 // mapping between them if so. 107 if (!areTypesIsomorphic(DstTy, SrcTy)) { 108 // Oops, they aren't isomorphic. Just discard this request by rolling out 109 // any speculative mappings we've established. 110 for (unsigned i = 0, e = SpeculativeTypes.size(); i != e; ++i) 111 MappedTypes.erase(SpeculativeTypes[i]); 112 } 113 SpeculativeTypes.clear(); 114} 115 116/// areTypesIsomorphic - Recursively walk this pair of types, returning true 117/// if they are isomorphic, false if they are not. 118bool TypeMapTy::areTypesIsomorphic(Type *DstTy, Type *SrcTy) { 119 // Two types with differing kinds are clearly not isomorphic. 120 if (DstTy->getTypeID() != SrcTy->getTypeID()) return false; 121 122 // If we have an entry in the MappedTypes table, then we have our answer. 123 Type *&Entry = MappedTypes[SrcTy]; 124 if (Entry) 125 return Entry == DstTy; 126 127 // Two identical types are clearly isomorphic. Remember this 128 // non-speculatively. 129 if (DstTy == SrcTy) { 130 Entry = DstTy; 131 return true; 132 } 133 134 // Okay, we have two types with identical kinds that we haven't seen before. 135 136 // If this is an opaque struct type, special case it. 137 if (StructType *SSTy = dyn_cast<StructType>(SrcTy)) { 138 // Mapping an opaque type to any struct, just keep the dest struct. 139 if (SSTy->isOpaque()) { 140 Entry = DstTy; 141 SpeculativeTypes.push_back(SrcTy); 142 return true; 143 } 144 145 // Mapping a non-opaque source type to an opaque dest. If this is the first 146 // type that we're mapping onto this destination type then we succeed. Keep 147 // the dest, but fill it in later. This doesn't need to be speculative. If 148 // this is the second (different) type that we're trying to map onto the 149 // same opaque type then we fail. 150 if (cast<StructType>(DstTy)->isOpaque()) { 151 // We can only map one source type onto the opaque destination type. 152 if (!DstResolvedOpaqueTypes.insert(cast<StructType>(DstTy))) 153 return false; 154 SrcDefinitionsToResolve.push_back(SSTy); 155 Entry = DstTy; 156 return true; 157 } 158 } 159 160 // If the number of subtypes disagree between the two types, then we fail. 161 if (SrcTy->getNumContainedTypes() != DstTy->getNumContainedTypes()) 162 return false; 163 164 // Fail if any of the extra properties (e.g. array size) of the type disagree. 165 if (isa<IntegerType>(DstTy)) 166 return false; // bitwidth disagrees. 167 if (PointerType *PT = dyn_cast<PointerType>(DstTy)) { 168 if (PT->getAddressSpace() != cast<PointerType>(SrcTy)->getAddressSpace()) 169 return false; 170 171 } else if (FunctionType *FT = dyn_cast<FunctionType>(DstTy)) { 172 if (FT->isVarArg() != cast<FunctionType>(SrcTy)->isVarArg()) 173 return false; 174 } else if (StructType *DSTy = dyn_cast<StructType>(DstTy)) { 175 StructType *SSTy = cast<StructType>(SrcTy); 176 if (DSTy->isLiteral() != SSTy->isLiteral() || 177 DSTy->isPacked() != SSTy->isPacked()) 178 return false; 179 } else if (ArrayType *DATy = dyn_cast<ArrayType>(DstTy)) { 180 if (DATy->getNumElements() != cast<ArrayType>(SrcTy)->getNumElements()) 181 return false; 182 } else if (VectorType *DVTy = dyn_cast<VectorType>(DstTy)) { 183 if (DVTy->getNumElements() != cast<VectorType>(SrcTy)->getNumElements()) 184 return false; 185 } 186 187 // Otherwise, we speculate that these two types will line up and recursively 188 // check the subelements. 189 Entry = DstTy; 190 SpeculativeTypes.push_back(SrcTy); 191 192 for (unsigned i = 0, e = SrcTy->getNumContainedTypes(); i != e; ++i) 193 if (!areTypesIsomorphic(DstTy->getContainedType(i), 194 SrcTy->getContainedType(i))) 195 return false; 196 197 // If everything seems to have lined up, then everything is great. 198 return true; 199} 200 201/// linkDefinedTypeBodies - Produce a body for an opaque type in the dest 202/// module from a type definition in the source module. 203void TypeMapTy::linkDefinedTypeBodies() { 204 SmallVector<Type*, 16> Elements; 205 SmallString<16> TmpName; 206 207 // Note that processing entries in this loop (calling 'get') can add new 208 // entries to the SrcDefinitionsToResolve vector. 209 while (!SrcDefinitionsToResolve.empty()) { 210 StructType *SrcSTy = SrcDefinitionsToResolve.pop_back_val(); 211 StructType *DstSTy = cast<StructType>(MappedTypes[SrcSTy]); 212 213 // TypeMap is a many-to-one mapping, if there were multiple types that 214 // provide a body for DstSTy then previous iterations of this loop may have 215 // already handled it. Just ignore this case. 216 if (!DstSTy->isOpaque()) continue; 217 assert(!SrcSTy->isOpaque() && "Not resolving a definition?"); 218 219 // Map the body of the source type over to a new body for the dest type. 220 Elements.resize(SrcSTy->getNumElements()); 221 for (unsigned i = 0, e = Elements.size(); i != e; ++i) 222 Elements[i] = getImpl(SrcSTy->getElementType(i)); 223 224 DstSTy->setBody(Elements, SrcSTy->isPacked()); 225 226 // If DstSTy has no name or has a longer name than STy, then viciously steal 227 // STy's name. 228 if (!SrcSTy->hasName()) continue; 229 StringRef SrcName = SrcSTy->getName(); 230 231 if (!DstSTy->hasName() || DstSTy->getName().size() > SrcName.size()) { 232 TmpName.insert(TmpName.end(), SrcName.begin(), SrcName.end()); 233 SrcSTy->setName(""); 234 DstSTy->setName(TmpName.str()); 235 TmpName.clear(); 236 } 237 } 238 239 DstResolvedOpaqueTypes.clear(); 240} 241 242/// get - Return the mapped type to use for the specified input type from the 243/// source module. 244Type *TypeMapTy::get(Type *Ty) { 245 Type *Result = getImpl(Ty); 246 247 // If this caused a reference to any struct type, resolve it before returning. 248 if (!SrcDefinitionsToResolve.empty()) 249 linkDefinedTypeBodies(); 250 return Result; 251} 252 253/// getImpl - This is the recursive version of get(). 254Type *TypeMapTy::getImpl(Type *Ty) { 255 // If we already have an entry for this type, return it. 256 Type **Entry = &MappedTypes[Ty]; 257 if (*Entry) return *Entry; 258 259 // If this is not a named struct type, then just map all of the elements and 260 // then rebuild the type from inside out. 261 if (!isa<StructType>(Ty) || cast<StructType>(Ty)->isLiteral()) { 262 // If there are no element types to map, then the type is itself. This is 263 // true for the anonymous {} struct, things like 'float', integers, etc. 264 if (Ty->getNumContainedTypes() == 0) 265 return *Entry = Ty; 266 267 // Remap all of the elements, keeping track of whether any of them change. 268 bool AnyChange = false; 269 SmallVector<Type*, 4> ElementTypes; 270 ElementTypes.resize(Ty->getNumContainedTypes()); 271 for (unsigned i = 0, e = Ty->getNumContainedTypes(); i != e; ++i) { 272 ElementTypes[i] = getImpl(Ty->getContainedType(i)); 273 AnyChange |= ElementTypes[i] != Ty->getContainedType(i); 274 } 275 276 // If we found our type while recursively processing stuff, just use it. 277 Entry = &MappedTypes[Ty]; 278 if (*Entry) return *Entry; 279 280 // If all of the element types mapped directly over, then the type is usable 281 // as-is. 282 if (!AnyChange) 283 return *Entry = Ty; 284 285 // Otherwise, rebuild a modified type. 286 switch (Ty->getTypeID()) { 287 default: llvm_unreachable("unknown derived type to remap"); 288 case Type::ArrayTyID: 289 return *Entry = ArrayType::get(ElementTypes[0], 290 cast<ArrayType>(Ty)->getNumElements()); 291 case Type::VectorTyID: 292 return *Entry = VectorType::get(ElementTypes[0], 293 cast<VectorType>(Ty)->getNumElements()); 294 case Type::PointerTyID: 295 return *Entry = PointerType::get(ElementTypes[0], 296 cast<PointerType>(Ty)->getAddressSpace()); 297 case Type::FunctionTyID: 298 return *Entry = FunctionType::get(ElementTypes[0], 299 makeArrayRef(ElementTypes).slice(1), 300 cast<FunctionType>(Ty)->isVarArg()); 301 case Type::StructTyID: 302 // Note that this is only reached for anonymous structs. 303 return *Entry = StructType::get(Ty->getContext(), ElementTypes, 304 cast<StructType>(Ty)->isPacked()); 305 } 306 } 307 308 // Otherwise, this is an unmapped named struct. If the struct can be directly 309 // mapped over, just use it as-is. This happens in a case when the linked-in 310 // module has something like: 311 // %T = type {%T*, i32} 312 // @GV = global %T* null 313 // where T does not exist at all in the destination module. 314 // 315 // The other case we watch for is when the type is not in the destination 316 // module, but that it has to be rebuilt because it refers to something that 317 // is already mapped. For example, if the destination module has: 318 // %A = type { i32 } 319 // and the source module has something like 320 // %A' = type { i32 } 321 // %B = type { %A'* } 322 // @GV = global %B* null 323 // then we want to create a new type: "%B = type { %A*}" and have it take the 324 // pristine "%B" name from the source module. 325 // 326 // To determine which case this is, we have to recursively walk the type graph 327 // speculating that we'll be able to reuse it unmodified. Only if this is 328 // safe would we map the entire thing over. Because this is an optimization, 329 // and is not required for the prettiness of the linked module, we just skip 330 // it and always rebuild a type here. 331 StructType *STy = cast<StructType>(Ty); 332 333 // If the type is opaque, we can just use it directly. 334 if (STy->isOpaque()) { 335 // A named structure type from src module is used. Add it to the Set of 336 // identified structs in the destination module. 337 DstStructTypesSet.insert(STy); 338 return *Entry = STy; 339 } 340 341 // Otherwise we create a new type and resolve its body later. This will be 342 // resolved by the top level of get(). 343 SrcDefinitionsToResolve.push_back(STy); 344 StructType *DTy = StructType::create(STy->getContext()); 345 // A new identified structure type was created. Add it to the set of 346 // identified structs in the destination module. 347 DstStructTypesSet.insert(DTy); 348 DstResolvedOpaqueTypes.insert(DTy); 349 return *Entry = DTy; 350} 351 352//===----------------------------------------------------------------------===// 353// ModuleLinker implementation. 354//===----------------------------------------------------------------------===// 355 356namespace { 357 class ModuleLinker; 358 359 /// ValueMaterializerTy - Creates prototypes for functions that are lazily 360 /// linked on the fly. This speeds up linking for modules with many 361 /// lazily linked functions of which few get used. 362 class ValueMaterializerTy : public ValueMaterializer { 363 TypeMapTy &TypeMap; 364 Module *DstM; 365 std::vector<Function*> &LazilyLinkFunctions; 366 public: 367 ValueMaterializerTy(TypeMapTy &TypeMap, Module *DstM, 368 std::vector<Function*> &LazilyLinkFunctions) : 369 ValueMaterializer(), TypeMap(TypeMap), DstM(DstM), 370 LazilyLinkFunctions(LazilyLinkFunctions) { 371 } 372 373 virtual Value *materializeValueFor(Value *V); 374 }; 375 376 /// ModuleLinker - This is an implementation class for the LinkModules 377 /// function, which is the entrypoint for this file. 378 class ModuleLinker { 379 Module *DstM, *SrcM; 380 381 TypeMapTy TypeMap; 382 ValueMaterializerTy ValMaterializer; 383 384 /// ValueMap - Mapping of values from what they used to be in Src, to what 385 /// they are now in DstM. ValueToValueMapTy is a ValueMap, which involves 386 /// some overhead due to the use of Value handles which the Linker doesn't 387 /// actually need, but this allows us to reuse the ValueMapper code. 388 ValueToValueMapTy ValueMap; 389 390 struct AppendingVarInfo { 391 GlobalVariable *NewGV; // New aggregate global in dest module. 392 Constant *DstInit; // Old initializer from dest module. 393 Constant *SrcInit; // Old initializer from src module. 394 }; 395 396 std::vector<AppendingVarInfo> AppendingVars; 397 398 unsigned Mode; // Mode to treat source module. 399 400 // Set of items not to link in from source. 401 SmallPtrSet<const Value*, 16> DoNotLinkFromSource; 402 403 // Vector of functions to lazily link in. 404 std::vector<Function*> LazilyLinkFunctions; 405 406 public: 407 std::string ErrorMsg; 408 409 ModuleLinker(Module *dstM, TypeSet &Set, Module *srcM, unsigned mode) 410 : DstM(dstM), SrcM(srcM), TypeMap(Set), 411 ValMaterializer(TypeMap, DstM, LazilyLinkFunctions), 412 Mode(mode) { } 413 414 bool run(); 415 416 private: 417 /// emitError - Helper method for setting a message and returning an error 418 /// code. 419 bool emitError(const Twine &Message) { 420 ErrorMsg = Message.str(); 421 return true; 422 } 423 424 /// getLinkageResult - This analyzes the two global values and determines 425 /// what the result will look like in the destination module. 426 bool getLinkageResult(GlobalValue *Dest, const GlobalValue *Src, 427 GlobalValue::LinkageTypes <, 428 GlobalValue::VisibilityTypes &Vis, 429 bool &LinkFromSrc); 430 431 /// getLinkedToGlobal - Given a global in the source module, return the 432 /// global in the destination module that is being linked to, if any. 433 GlobalValue *getLinkedToGlobal(GlobalValue *SrcGV) { 434 // If the source has no name it can't link. If it has local linkage, 435 // there is no name match-up going on. 436 if (!SrcGV->hasName() || SrcGV->hasLocalLinkage()) 437 return 0; 438 439 // Otherwise see if we have a match in the destination module's symtab. 440 GlobalValue *DGV = DstM->getNamedValue(SrcGV->getName()); 441 if (DGV == 0) return 0; 442 443 // If we found a global with the same name in the dest module, but it has 444 // internal linkage, we are really not doing any linkage here. 445 if (DGV->hasLocalLinkage()) 446 return 0; 447 448 // Otherwise, we do in fact link to the destination global. 449 return DGV; 450 } 451 452 void computeTypeMapping(); 453 454 bool linkAppendingVarProto(GlobalVariable *DstGV, GlobalVariable *SrcGV); 455 bool linkGlobalProto(GlobalVariable *SrcGV); 456 bool linkFunctionProto(Function *SrcF); 457 bool linkAliasProto(GlobalAlias *SrcA); 458 bool linkModuleFlagsMetadata(); 459 460 void linkAppendingVarInit(const AppendingVarInfo &AVI); 461 void linkGlobalInits(); 462 void linkFunctionBody(Function *Dst, Function *Src); 463 void linkAliasBodies(); 464 void linkNamedMDNodes(); 465 }; 466} 467 468/// forceRenaming - The LLVM SymbolTable class autorenames globals that conflict 469/// in the symbol table. This is good for all clients except for us. Go 470/// through the trouble to force this back. 471static void forceRenaming(GlobalValue *GV, StringRef Name) { 472 // If the global doesn't force its name or if it already has the right name, 473 // there is nothing for us to do. 474 if (GV->hasLocalLinkage() || GV->getName() == Name) 475 return; 476 477 Module *M = GV->getParent(); 478 479 // If there is a conflict, rename the conflict. 480 if (GlobalValue *ConflictGV = M->getNamedValue(Name)) { 481 GV->takeName(ConflictGV); 482 ConflictGV->setName(Name); // This will cause ConflictGV to get renamed 483 assert(ConflictGV->getName() != Name && "forceRenaming didn't work"); 484 } else { 485 GV->setName(Name); // Force the name back 486 } 487} 488 489/// copyGVAttributes - copy additional attributes (those not needed to construct 490/// a GlobalValue) from the SrcGV to the DestGV. 491static void copyGVAttributes(GlobalValue *DestGV, const GlobalValue *SrcGV) { 492 // Use the maximum alignment, rather than just copying the alignment of SrcGV. 493 unsigned Alignment = std::max(DestGV->getAlignment(), SrcGV->getAlignment()); 494 DestGV->copyAttributesFrom(SrcGV); 495 DestGV->setAlignment(Alignment); 496 497 forceRenaming(DestGV, SrcGV->getName()); 498} 499 500static bool isLessConstraining(GlobalValue::VisibilityTypes a, 501 GlobalValue::VisibilityTypes b) { 502 if (a == GlobalValue::HiddenVisibility) 503 return false; 504 if (b == GlobalValue::HiddenVisibility) 505 return true; 506 if (a == GlobalValue::ProtectedVisibility) 507 return false; 508 if (b == GlobalValue::ProtectedVisibility) 509 return true; 510 return false; 511} 512 513Value *ValueMaterializerTy::materializeValueFor(Value *V) { 514 Function *SF = dyn_cast<Function>(V); 515 if (!SF) 516 return NULL; 517 518 Function *DF = Function::Create(TypeMap.get(SF->getFunctionType()), 519 SF->getLinkage(), SF->getName(), DstM); 520 copyGVAttributes(DF, SF); 521 522 LazilyLinkFunctions.push_back(SF); 523 return DF; 524} 525 526 527/// getLinkageResult - This analyzes the two global values and determines what 528/// the result will look like in the destination module. In particular, it 529/// computes the resultant linkage type and visibility, computes whether the 530/// global in the source should be copied over to the destination (replacing 531/// the existing one), and computes whether this linkage is an error or not. 532bool ModuleLinker::getLinkageResult(GlobalValue *Dest, const GlobalValue *Src, 533 GlobalValue::LinkageTypes <, 534 GlobalValue::VisibilityTypes &Vis, 535 bool &LinkFromSrc) { 536 assert(Dest && "Must have two globals being queried"); 537 assert(!Src->hasLocalLinkage() && 538 "If Src has internal linkage, Dest shouldn't be set!"); 539 540 bool SrcIsDeclaration = Src->isDeclaration() && !Src->isMaterializable(); 541 bool DestIsDeclaration = Dest->isDeclaration(); 542 543 if (SrcIsDeclaration) { 544 // If Src is external or if both Src & Dest are external.. Just link the 545 // external globals, we aren't adding anything. 546 if (Src->hasDLLImportLinkage()) { 547 // If one of GVs has DLLImport linkage, result should be dllimport'ed. 548 if (DestIsDeclaration) { 549 LinkFromSrc = true; 550 LT = Src->getLinkage(); 551 } 552 } else if (Dest->hasExternalWeakLinkage()) { 553 // If the Dest is weak, use the source linkage. 554 LinkFromSrc = true; 555 LT = Src->getLinkage(); 556 } else { 557 LinkFromSrc = false; 558 LT = Dest->getLinkage(); 559 } 560 } else if (DestIsDeclaration && !Dest->hasDLLImportLinkage()) { 561 // If Dest is external but Src is not: 562 LinkFromSrc = true; 563 LT = Src->getLinkage(); 564 } else if (Src->isWeakForLinker()) { 565 // At this point we know that Dest has LinkOnce, External*, Weak, Common, 566 // or DLL* linkage. 567 if (Dest->hasExternalWeakLinkage() || 568 Dest->hasAvailableExternallyLinkage() || 569 (Dest->hasLinkOnceLinkage() && 570 (Src->hasWeakLinkage() || Src->hasCommonLinkage()))) { 571 LinkFromSrc = true; 572 LT = Src->getLinkage(); 573 } else { 574 LinkFromSrc = false; 575 LT = Dest->getLinkage(); 576 } 577 } else if (Dest->isWeakForLinker()) { 578 // At this point we know that Src has External* or DLL* linkage. 579 if (Src->hasExternalWeakLinkage()) { 580 LinkFromSrc = false; 581 LT = Dest->getLinkage(); 582 } else { 583 LinkFromSrc = true; 584 LT = GlobalValue::ExternalLinkage; 585 } 586 } else { 587 assert((Dest->hasExternalLinkage() || Dest->hasDLLImportLinkage() || 588 Dest->hasDLLExportLinkage() || Dest->hasExternalWeakLinkage()) && 589 (Src->hasExternalLinkage() || Src->hasDLLImportLinkage() || 590 Src->hasDLLExportLinkage() || Src->hasExternalWeakLinkage()) && 591 "Unexpected linkage type!"); 592 return emitError("Linking globals named '" + Src->getName() + 593 "': symbol multiply defined!"); 594 } 595 596 // Compute the visibility. We follow the rules in the System V Application 597 // Binary Interface. 598 Vis = isLessConstraining(Src->getVisibility(), Dest->getVisibility()) ? 599 Dest->getVisibility() : Src->getVisibility(); 600 return false; 601} 602 603/// computeTypeMapping - Loop over all of the linked values to compute type 604/// mappings. For example, if we link "extern Foo *x" and "Foo *x = NULL", then 605/// we have two struct types 'Foo' but one got renamed when the module was 606/// loaded into the same LLVMContext. 607void ModuleLinker::computeTypeMapping() { 608 // Incorporate globals. 609 for (Module::global_iterator I = SrcM->global_begin(), 610 E = SrcM->global_end(); I != E; ++I) { 611 GlobalValue *DGV = getLinkedToGlobal(I); 612 if (DGV == 0) continue; 613 614 if (!DGV->hasAppendingLinkage() || !I->hasAppendingLinkage()) { 615 TypeMap.addTypeMapping(DGV->getType(), I->getType()); 616 continue; 617 } 618 619 // Unify the element type of appending arrays. 620 ArrayType *DAT = cast<ArrayType>(DGV->getType()->getElementType()); 621 ArrayType *SAT = cast<ArrayType>(I->getType()->getElementType()); 622 TypeMap.addTypeMapping(DAT->getElementType(), SAT->getElementType()); 623 } 624 625 // Incorporate functions. 626 for (Module::iterator I = SrcM->begin(), E = SrcM->end(); I != E; ++I) { 627 if (GlobalValue *DGV = getLinkedToGlobal(I)) 628 TypeMap.addTypeMapping(DGV->getType(), I->getType()); 629 } 630 631 // Incorporate types by name, scanning all the types in the source module. 632 // At this point, the destination module may have a type "%foo = { i32 }" for 633 // example. When the source module got loaded into the same LLVMContext, if 634 // it had the same type, it would have been renamed to "%foo.42 = { i32 }". 635 TypeFinder SrcStructTypes; 636 SrcStructTypes.run(*SrcM, true); 637 SmallPtrSet<StructType*, 32> SrcStructTypesSet(SrcStructTypes.begin(), 638 SrcStructTypes.end()); 639 640 for (unsigned i = 0, e = SrcStructTypes.size(); i != e; ++i) { 641 StructType *ST = SrcStructTypes[i]; 642 if (!ST->hasName()) continue; 643 644 // Check to see if there is a dot in the name followed by a digit. 645 size_t DotPos = ST->getName().rfind('.'); 646 if (DotPos == 0 || DotPos == StringRef::npos || 647 ST->getName().back() == '.' || 648 !isdigit(static_cast<unsigned char>(ST->getName()[DotPos+1]))) 649 continue; 650 651 // Check to see if the destination module has a struct with the prefix name. 652 if (StructType *DST = DstM->getTypeByName(ST->getName().substr(0, DotPos))) 653 // Don't use it if this actually came from the source module. They're in 654 // the same LLVMContext after all. Also don't use it unless the type is 655 // actually used in the destination module. This can happen in situations 656 // like this: 657 // 658 // Module A Module B 659 // -------- -------- 660 // %Z = type { %A } %B = type { %C.1 } 661 // %A = type { %B.1, [7 x i8] } %C.1 = type { i8* } 662 // %B.1 = type { %C } %A.2 = type { %B.3, [5 x i8] } 663 // %C = type { i8* } %B.3 = type { %C.1 } 664 // 665 // When we link Module B with Module A, the '%B' in Module B is 666 // used. However, that would then use '%C.1'. But when we process '%C.1', 667 // we prefer to take the '%C' version. So we are then left with both 668 // '%C.1' and '%C' being used for the same types. This leads to some 669 // variables using one type and some using the other. 670 if (!SrcStructTypesSet.count(DST) && TypeMap.DstStructTypesSet.count(DST)) 671 TypeMap.addTypeMapping(DST, ST); 672 } 673 674 // Don't bother incorporating aliases, they aren't generally typed well. 675 676 // Now that we have discovered all of the type equivalences, get a body for 677 // any 'opaque' types in the dest module that are now resolved. 678 TypeMap.linkDefinedTypeBodies(); 679} 680 681/// linkAppendingVarProto - If there were any appending global variables, link 682/// them together now. Return true on error. 683bool ModuleLinker::linkAppendingVarProto(GlobalVariable *DstGV, 684 GlobalVariable *SrcGV) { 685 686 if (!SrcGV->hasAppendingLinkage() || !DstGV->hasAppendingLinkage()) 687 return emitError("Linking globals named '" + SrcGV->getName() + 688 "': can only link appending global with another appending global!"); 689 690 ArrayType *DstTy = cast<ArrayType>(DstGV->getType()->getElementType()); 691 ArrayType *SrcTy = 692 cast<ArrayType>(TypeMap.get(SrcGV->getType()->getElementType())); 693 Type *EltTy = DstTy->getElementType(); 694 695 // Check to see that they two arrays agree on type. 696 if (EltTy != SrcTy->getElementType()) 697 return emitError("Appending variables with different element types!"); 698 if (DstGV->isConstant() != SrcGV->isConstant()) 699 return emitError("Appending variables linked with different const'ness!"); 700 701 if (DstGV->getAlignment() != SrcGV->getAlignment()) 702 return emitError( 703 "Appending variables with different alignment need to be linked!"); 704 705 if (DstGV->getVisibility() != SrcGV->getVisibility()) 706 return emitError( 707 "Appending variables with different visibility need to be linked!"); 708 709 if (DstGV->hasUnnamedAddr() != SrcGV->hasUnnamedAddr()) 710 return emitError( 711 "Appending variables with different unnamed_addr need to be linked!"); 712 713 if (DstGV->getSection() != SrcGV->getSection()) 714 return emitError( 715 "Appending variables with different section name need to be linked!"); 716 717 uint64_t NewSize = DstTy->getNumElements() + SrcTy->getNumElements(); 718 ArrayType *NewType = ArrayType::get(EltTy, NewSize); 719 720 // Create the new global variable. 721 GlobalVariable *NG = 722 new GlobalVariable(*DstGV->getParent(), NewType, SrcGV->isConstant(), 723 DstGV->getLinkage(), /*init*/0, /*name*/"", DstGV, 724 DstGV->getThreadLocalMode(), 725 DstGV->getType()->getAddressSpace()); 726 727 // Propagate alignment, visibility and section info. 728 copyGVAttributes(NG, DstGV); 729 730 AppendingVarInfo AVI; 731 AVI.NewGV = NG; 732 AVI.DstInit = DstGV->getInitializer(); 733 AVI.SrcInit = SrcGV->getInitializer(); 734 AppendingVars.push_back(AVI); 735 736 // Replace any uses of the two global variables with uses of the new 737 // global. 738 ValueMap[SrcGV] = ConstantExpr::getBitCast(NG, TypeMap.get(SrcGV->getType())); 739 740 DstGV->replaceAllUsesWith(ConstantExpr::getBitCast(NG, DstGV->getType())); 741 DstGV->eraseFromParent(); 742 743 // Track the source variable so we don't try to link it. 744 DoNotLinkFromSource.insert(SrcGV); 745 746 return false; 747} 748 749/// linkGlobalProto - Loop through the global variables in the src module and 750/// merge them into the dest module. 751bool ModuleLinker::linkGlobalProto(GlobalVariable *SGV) { 752 GlobalValue *DGV = getLinkedToGlobal(SGV); 753 llvm::Optional<GlobalValue::VisibilityTypes> NewVisibility; 754 bool HasUnnamedAddr = SGV->hasUnnamedAddr(); 755 756 if (DGV) { 757 // Concatenation of appending linkage variables is magic and handled later. 758 if (DGV->hasAppendingLinkage() || SGV->hasAppendingLinkage()) 759 return linkAppendingVarProto(cast<GlobalVariable>(DGV), SGV); 760 761 // Determine whether linkage of these two globals follows the source 762 // module's definition or the destination module's definition. 763 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; 764 GlobalValue::VisibilityTypes NV; 765 bool LinkFromSrc = false; 766 if (getLinkageResult(DGV, SGV, NewLinkage, NV, LinkFromSrc)) 767 return true; 768 NewVisibility = NV; 769 HasUnnamedAddr = HasUnnamedAddr && DGV->hasUnnamedAddr(); 770 771 // If we're not linking from the source, then keep the definition that we 772 // have. 773 if (!LinkFromSrc) { 774 // Special case for const propagation. 775 if (GlobalVariable *DGVar = dyn_cast<GlobalVariable>(DGV)) 776 if (DGVar->isDeclaration() && SGV->isConstant() && !DGVar->isConstant()) 777 DGVar->setConstant(true); 778 779 // Set calculated linkage, visibility and unnamed_addr. 780 DGV->setLinkage(NewLinkage); 781 DGV->setVisibility(*NewVisibility); 782 DGV->setUnnamedAddr(HasUnnamedAddr); 783 784 // Make sure to remember this mapping. 785 ValueMap[SGV] = ConstantExpr::getBitCast(DGV,TypeMap.get(SGV->getType())); 786 787 // Track the source global so that we don't attempt to copy it over when 788 // processing global initializers. 789 DoNotLinkFromSource.insert(SGV); 790 791 return false; 792 } 793 } 794 795 // No linking to be performed or linking from the source: simply create an 796 // identical version of the symbol over in the dest module... the 797 // initializer will be filled in later by LinkGlobalInits. 798 GlobalVariable *NewDGV = 799 new GlobalVariable(*DstM, TypeMap.get(SGV->getType()->getElementType()), 800 SGV->isConstant(), SGV->getLinkage(), /*init*/0, 801 SGV->getName(), /*insertbefore*/0, 802 SGV->getThreadLocalMode(), 803 SGV->getType()->getAddressSpace()); 804 // Propagate alignment, visibility and section info. 805 copyGVAttributes(NewDGV, SGV); 806 if (NewVisibility) 807 NewDGV->setVisibility(*NewVisibility); 808 NewDGV->setUnnamedAddr(HasUnnamedAddr); 809 810 if (DGV) { 811 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDGV, DGV->getType())); 812 DGV->eraseFromParent(); 813 } 814 815 // Make sure to remember this mapping. 816 ValueMap[SGV] = NewDGV; 817 return false; 818} 819 820/// linkFunctionProto - Link the function in the source module into the 821/// destination module if needed, setting up mapping information. 822bool ModuleLinker::linkFunctionProto(Function *SF) { 823 GlobalValue *DGV = getLinkedToGlobal(SF); 824 llvm::Optional<GlobalValue::VisibilityTypes> NewVisibility; 825 bool HasUnnamedAddr = SF->hasUnnamedAddr(); 826 827 if (DGV) { 828 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; 829 bool LinkFromSrc = false; 830 GlobalValue::VisibilityTypes NV; 831 if (getLinkageResult(DGV, SF, NewLinkage, NV, LinkFromSrc)) 832 return true; 833 NewVisibility = NV; 834 HasUnnamedAddr = HasUnnamedAddr && DGV->hasUnnamedAddr(); 835 836 if (!LinkFromSrc) { 837 // Set calculated linkage 838 DGV->setLinkage(NewLinkage); 839 DGV->setVisibility(*NewVisibility); 840 DGV->setUnnamedAddr(HasUnnamedAddr); 841 842 // Make sure to remember this mapping. 843 ValueMap[SF] = ConstantExpr::getBitCast(DGV, TypeMap.get(SF->getType())); 844 845 // Track the function from the source module so we don't attempt to remap 846 // it. 847 DoNotLinkFromSource.insert(SF); 848 849 return false; 850 } 851 } 852 853 // If the function is to be lazily linked, don't create it just yet. 854 // The ValueMaterializerTy will deal with creating it if it's used. 855 if (!DGV && (SF->hasLocalLinkage() || SF->hasLinkOnceLinkage() || 856 SF->hasAvailableExternallyLinkage())) { 857 DoNotLinkFromSource.insert(SF); 858 return false; 859 } 860 861 // If there is no linkage to be performed or we are linking from the source, 862 // bring SF over. 863 Function *NewDF = Function::Create(TypeMap.get(SF->getFunctionType()), 864 SF->getLinkage(), SF->getName(), DstM); 865 copyGVAttributes(NewDF, SF); 866 if (NewVisibility) 867 NewDF->setVisibility(*NewVisibility); 868 NewDF->setUnnamedAddr(HasUnnamedAddr); 869 870 if (DGV) { 871 // Any uses of DF need to change to NewDF, with cast. 872 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDF, DGV->getType())); 873 DGV->eraseFromParent(); 874 } 875 876 ValueMap[SF] = NewDF; 877 return false; 878} 879 880/// LinkAliasProto - Set up prototypes for any aliases that come over from the 881/// source module. 882bool ModuleLinker::linkAliasProto(GlobalAlias *SGA) { 883 GlobalValue *DGV = getLinkedToGlobal(SGA); 884 llvm::Optional<GlobalValue::VisibilityTypes> NewVisibility; 885 886 if (DGV) { 887 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; 888 GlobalValue::VisibilityTypes NV; 889 bool LinkFromSrc = false; 890 if (getLinkageResult(DGV, SGA, NewLinkage, NV, LinkFromSrc)) 891 return true; 892 NewVisibility = NV; 893 894 if (!LinkFromSrc) { 895 // Set calculated linkage. 896 DGV->setLinkage(NewLinkage); 897 DGV->setVisibility(*NewVisibility); 898 899 // Make sure to remember this mapping. 900 ValueMap[SGA] = ConstantExpr::getBitCast(DGV,TypeMap.get(SGA->getType())); 901 902 // Track the alias from the source module so we don't attempt to remap it. 903 DoNotLinkFromSource.insert(SGA); 904 905 return false; 906 } 907 } 908 909 // If there is no linkage to be performed or we're linking from the source, 910 // bring over SGA. 911 GlobalAlias *NewDA = new GlobalAlias(TypeMap.get(SGA->getType()), 912 SGA->getLinkage(), SGA->getName(), 913 /*aliasee*/0, DstM); 914 copyGVAttributes(NewDA, SGA); 915 if (NewVisibility) 916 NewDA->setVisibility(*NewVisibility); 917 918 if (DGV) { 919 // Any uses of DGV need to change to NewDA, with cast. 920 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDA, DGV->getType())); 921 DGV->eraseFromParent(); 922 } 923 924 ValueMap[SGA] = NewDA; 925 return false; 926} 927 928static void getArrayElements(Constant *C, SmallVectorImpl<Constant*> &Dest) { 929 unsigned NumElements = cast<ArrayType>(C->getType())->getNumElements(); 930 931 for (unsigned i = 0; i != NumElements; ++i) 932 Dest.push_back(C->getAggregateElement(i)); 933} 934 935void ModuleLinker::linkAppendingVarInit(const AppendingVarInfo &AVI) { 936 // Merge the initializer. 937 SmallVector<Constant*, 16> Elements; 938 getArrayElements(AVI.DstInit, Elements); 939 940 Constant *SrcInit = MapValue(AVI.SrcInit, ValueMap, RF_None, &TypeMap, &ValMaterializer); 941 getArrayElements(SrcInit, Elements); 942 943 ArrayType *NewType = cast<ArrayType>(AVI.NewGV->getType()->getElementType()); 944 AVI.NewGV->setInitializer(ConstantArray::get(NewType, Elements)); 945} 946 947/// linkGlobalInits - Update the initializers in the Dest module now that all 948/// globals that may be referenced are in Dest. 949void ModuleLinker::linkGlobalInits() { 950 // Loop over all of the globals in the src module, mapping them over as we go 951 for (Module::const_global_iterator I = SrcM->global_begin(), 952 E = SrcM->global_end(); I != E; ++I) { 953 954 // Only process initialized GV's or ones not already in dest. 955 if (!I->hasInitializer() || DoNotLinkFromSource.count(I)) continue; 956 957 // Grab destination global variable. 958 GlobalVariable *DGV = cast<GlobalVariable>(ValueMap[I]); 959 // Figure out what the initializer looks like in the dest module. 960 DGV->setInitializer(MapValue(I->getInitializer(), ValueMap, 961 RF_None, &TypeMap, &ValMaterializer)); 962 } 963} 964 965/// linkFunctionBody - Copy the source function over into the dest function and 966/// fix up references to values. At this point we know that Dest is an external 967/// function, and that Src is not. 968void ModuleLinker::linkFunctionBody(Function *Dst, Function *Src) { 969 assert(Src && Dst && Dst->isDeclaration() && !Src->isDeclaration()); 970 971 // Go through and convert function arguments over, remembering the mapping. 972 Function::arg_iterator DI = Dst->arg_begin(); 973 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end(); 974 I != E; ++I, ++DI) { 975 DI->setName(I->getName()); // Copy the name over. 976 977 // Add a mapping to our mapping. 978 ValueMap[I] = DI; 979 } 980 981 if (Mode == Linker::DestroySource) { 982 // Splice the body of the source function into the dest function. 983 Dst->getBasicBlockList().splice(Dst->end(), Src->getBasicBlockList()); 984 985 // At this point, all of the instructions and values of the function are now 986 // copied over. The only problem is that they are still referencing values in 987 // the Source function as operands. Loop through all of the operands of the 988 // functions and patch them up to point to the local versions. 989 for (Function::iterator BB = Dst->begin(), BE = Dst->end(); BB != BE; ++BB) 990 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) 991 RemapInstruction(I, ValueMap, RF_IgnoreMissingEntries, 992 &TypeMap, &ValMaterializer); 993 994 } else { 995 // Clone the body of the function into the dest function. 996 SmallVector<ReturnInst*, 8> Returns; // Ignore returns. 997 CloneFunctionInto(Dst, Src, ValueMap, false, Returns, "", NULL, 998 &TypeMap, &ValMaterializer); 999 } 1000 1001 // There is no need to map the arguments anymore. 1002 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end(); 1003 I != E; ++I) 1004 ValueMap.erase(I); 1005 1006} 1007 1008/// linkAliasBodies - Insert all of the aliases in Src into the Dest module. 1009void ModuleLinker::linkAliasBodies() { 1010 for (Module::alias_iterator I = SrcM->alias_begin(), E = SrcM->alias_end(); 1011 I != E; ++I) { 1012 if (DoNotLinkFromSource.count(I)) 1013 continue; 1014 if (Constant *Aliasee = I->getAliasee()) { 1015 GlobalAlias *DA = cast<GlobalAlias>(ValueMap[I]); 1016 DA->setAliasee(MapValue(Aliasee, ValueMap, RF_None, 1017 &TypeMap, &ValMaterializer)); 1018 } 1019 } 1020} 1021 1022/// linkNamedMDNodes - Insert all of the named MDNodes in Src into the Dest 1023/// module. 1024void ModuleLinker::linkNamedMDNodes() { 1025 const NamedMDNode *SrcModFlags = SrcM->getModuleFlagsMetadata(); 1026 for (Module::const_named_metadata_iterator I = SrcM->named_metadata_begin(), 1027 E = SrcM->named_metadata_end(); I != E; ++I) { 1028 // Don't link module flags here. Do them separately. 1029 if (&*I == SrcModFlags) continue; 1030 NamedMDNode *DestNMD = DstM->getOrInsertNamedMetadata(I->getName()); 1031 // Add Src elements into Dest node. 1032 for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) 1033 DestNMD->addOperand(MapValue(I->getOperand(i), ValueMap, 1034 RF_None, &TypeMap, &ValMaterializer)); 1035 } 1036} 1037 1038/// linkModuleFlagsMetadata - Merge the linker flags in Src into the Dest 1039/// module. 1040bool ModuleLinker::linkModuleFlagsMetadata() { 1041 // If the source module has no module flags, we are done. 1042 const NamedMDNode *SrcModFlags = SrcM->getModuleFlagsMetadata(); 1043 if (!SrcModFlags) return false; 1044 1045 // If the destination module doesn't have module flags yet, then just copy 1046 // over the source module's flags. 1047 NamedMDNode *DstModFlags = DstM->getOrInsertModuleFlagsMetadata(); 1048 if (DstModFlags->getNumOperands() == 0) { 1049 for (unsigned I = 0, E = SrcModFlags->getNumOperands(); I != E; ++I) 1050 DstModFlags->addOperand(SrcModFlags->getOperand(I)); 1051 1052 return false; 1053 } 1054 1055 // First build a map of the existing module flags and requirements. 1056 DenseMap<MDString*, MDNode*> Flags; 1057 SmallSetVector<MDNode*, 16> Requirements; 1058 for (unsigned I = 0, E = DstModFlags->getNumOperands(); I != E; ++I) { 1059 MDNode *Op = DstModFlags->getOperand(I); 1060 ConstantInt *Behavior = cast<ConstantInt>(Op->getOperand(0)); 1061 MDString *ID = cast<MDString>(Op->getOperand(1)); 1062 1063 if (Behavior->getZExtValue() == Module::Require) { 1064 Requirements.insert(cast<MDNode>(Op->getOperand(2))); 1065 } else { 1066 Flags[ID] = Op; 1067 } 1068 } 1069 1070 // Merge in the flags from the source module, and also collect its set of 1071 // requirements. 1072 bool HasErr = false; 1073 for (unsigned I = 0, E = SrcModFlags->getNumOperands(); I != E; ++I) { 1074 MDNode *SrcOp = SrcModFlags->getOperand(I); 1075 ConstantInt *SrcBehavior = cast<ConstantInt>(SrcOp->getOperand(0)); 1076 MDString *ID = cast<MDString>(SrcOp->getOperand(1)); 1077 MDNode *DstOp = Flags.lookup(ID); 1078 unsigned SrcBehaviorValue = SrcBehavior->getZExtValue(); 1079 1080 // If this is a requirement, add it and continue. 1081 if (SrcBehaviorValue == Module::Require) { 1082 // If the destination module does not already have this requirement, add 1083 // it. 1084 if (Requirements.insert(cast<MDNode>(SrcOp->getOperand(2)))) { 1085 DstModFlags->addOperand(SrcOp); 1086 } 1087 continue; 1088 } 1089 1090 // If there is no existing flag with this ID, just add it. 1091 if (!DstOp) { 1092 Flags[ID] = SrcOp; 1093 DstModFlags->addOperand(SrcOp); 1094 continue; 1095 } 1096 1097 // Otherwise, perform a merge. 1098 ConstantInt *DstBehavior = cast<ConstantInt>(DstOp->getOperand(0)); 1099 unsigned DstBehaviorValue = DstBehavior->getZExtValue(); 1100 1101 // If either flag has override behavior, handle it first. 1102 if (DstBehaviorValue == Module::Override) { 1103 // Diagnose inconsistent flags which both have override behavior. 1104 if (SrcBehaviorValue == Module::Override && 1105 SrcOp->getOperand(2) != DstOp->getOperand(2)) { 1106 HasErr |= emitError("linking module flags '" + ID->getString() + 1107 "': IDs have conflicting override values"); 1108 } 1109 continue; 1110 } else if (SrcBehaviorValue == Module::Override) { 1111 // Update the destination flag to that of the source. 1112 DstOp->replaceOperandWith(0, SrcBehavior); 1113 DstOp->replaceOperandWith(2, SrcOp->getOperand(2)); 1114 continue; 1115 } 1116 1117 // Diagnose inconsistent merge behavior types. 1118 if (SrcBehaviorValue != DstBehaviorValue) { 1119 HasErr |= emitError("linking module flags '" + ID->getString() + 1120 "': IDs have conflicting behaviors"); 1121 continue; 1122 } 1123 1124 // Perform the merge for standard behavior types. 1125 switch (SrcBehaviorValue) { 1126 case Module::Require: 1127 case Module::Override: assert(0 && "not possible"); break; 1128 case Module::Error: { 1129 // Emit an error if the values differ. 1130 if (SrcOp->getOperand(2) != DstOp->getOperand(2)) { 1131 HasErr |= emitError("linking module flags '" + ID->getString() + 1132 "': IDs have conflicting values"); 1133 } 1134 continue; 1135 } 1136 case Module::Warning: { 1137 // Emit a warning if the values differ. 1138 if (SrcOp->getOperand(2) != DstOp->getOperand(2)) { 1139 errs() << "WARNING: linking module flags '" << ID->getString() 1140 << "': IDs have conflicting values"; 1141 } 1142 continue; 1143 } 1144 case Module::Append: { 1145 MDNode *DstValue = cast<MDNode>(DstOp->getOperand(2)); 1146 MDNode *SrcValue = cast<MDNode>(SrcOp->getOperand(2)); 1147 unsigned NumOps = DstValue->getNumOperands() + SrcValue->getNumOperands(); 1148 Value **VP, **Values = VP = new Value*[NumOps]; 1149 for (unsigned i = 0, e = DstValue->getNumOperands(); i != e; ++i, ++VP) 1150 *VP = DstValue->getOperand(i); 1151 for (unsigned i = 0, e = SrcValue->getNumOperands(); i != e; ++i, ++VP) 1152 *VP = SrcValue->getOperand(i); 1153 DstOp->replaceOperandWith(2, MDNode::get(DstM->getContext(), 1154 ArrayRef<Value*>(Values, 1155 NumOps))); 1156 delete[] Values; 1157 break; 1158 } 1159 case Module::AppendUnique: { 1160 SmallSetVector<Value*, 16> Elts; 1161 MDNode *DstValue = cast<MDNode>(DstOp->getOperand(2)); 1162 MDNode *SrcValue = cast<MDNode>(SrcOp->getOperand(2)); 1163 for (unsigned i = 0, e = DstValue->getNumOperands(); i != e; ++i) 1164 Elts.insert(DstValue->getOperand(i)); 1165 for (unsigned i = 0, e = SrcValue->getNumOperands(); i != e; ++i) 1166 Elts.insert(SrcValue->getOperand(i)); 1167 DstOp->replaceOperandWith(2, MDNode::get(DstM->getContext(), 1168 ArrayRef<Value*>(Elts.begin(), 1169 Elts.end()))); 1170 break; 1171 } 1172 } 1173 } 1174 1175 // Check all of the requirements. 1176 for (unsigned I = 0, E = Requirements.size(); I != E; ++I) { 1177 MDNode *Requirement = Requirements[I]; 1178 MDString *Flag = cast<MDString>(Requirement->getOperand(0)); 1179 Value *ReqValue = Requirement->getOperand(1); 1180 1181 MDNode *Op = Flags[Flag]; 1182 if (!Op || Op->getOperand(2) != ReqValue) { 1183 HasErr |= emitError("linking module flags '" + Flag->getString() + 1184 "': does not have the required value"); 1185 continue; 1186 } 1187 } 1188 1189 return HasErr; 1190} 1191 1192bool ModuleLinker::run() { 1193 assert(DstM && "Null destination module"); 1194 assert(SrcM && "Null source module"); 1195 1196 // Inherit the target data from the source module if the destination module 1197 // doesn't have one already. 1198 if (DstM->getDataLayout().empty() && !SrcM->getDataLayout().empty()) 1199 DstM->setDataLayout(SrcM->getDataLayout()); 1200 1201 // Copy the target triple from the source to dest if the dest's is empty. 1202 if (DstM->getTargetTriple().empty() && !SrcM->getTargetTriple().empty()) 1203 DstM->setTargetTriple(SrcM->getTargetTriple()); 1204 1205 if (!SrcM->getDataLayout().empty() && !DstM->getDataLayout().empty() && 1206 SrcM->getDataLayout() != DstM->getDataLayout()) 1207 errs() << "WARNING: Linking two modules of different data layouts!\n"; 1208 if (!SrcM->getTargetTriple().empty() && 1209 DstM->getTargetTriple() != SrcM->getTargetTriple()) { 1210 errs() << "WARNING: Linking two modules of different target triples: "; 1211 if (!SrcM->getModuleIdentifier().empty()) 1212 errs() << SrcM->getModuleIdentifier() << ": "; 1213 errs() << "'" << SrcM->getTargetTriple() << "' and '" 1214 << DstM->getTargetTriple() << "'\n"; 1215 } 1216 1217 // Append the module inline asm string. 1218 if (!SrcM->getModuleInlineAsm().empty()) { 1219 if (DstM->getModuleInlineAsm().empty()) 1220 DstM->setModuleInlineAsm(SrcM->getModuleInlineAsm()); 1221 else 1222 DstM->setModuleInlineAsm(DstM->getModuleInlineAsm()+"\n"+ 1223 SrcM->getModuleInlineAsm()); 1224 } 1225 1226 // Loop over all of the linked values to compute type mappings. 1227 computeTypeMapping(); 1228 1229 // Insert all of the globals in src into the DstM module... without linking 1230 // initializers (which could refer to functions not yet mapped over). 1231 for (Module::global_iterator I = SrcM->global_begin(), 1232 E = SrcM->global_end(); I != E; ++I) 1233 if (linkGlobalProto(I)) 1234 return true; 1235 1236 // Link the functions together between the two modules, without doing function 1237 // bodies... this just adds external function prototypes to the DstM 1238 // function... We do this so that when we begin processing function bodies, 1239 // all of the global values that may be referenced are available in our 1240 // ValueMap. 1241 for (Module::iterator I = SrcM->begin(), E = SrcM->end(); I != E; ++I) 1242 if (linkFunctionProto(I)) 1243 return true; 1244 1245 // If there were any aliases, link them now. 1246 for (Module::alias_iterator I = SrcM->alias_begin(), 1247 E = SrcM->alias_end(); I != E; ++I) 1248 if (linkAliasProto(I)) 1249 return true; 1250 1251 for (unsigned i = 0, e = AppendingVars.size(); i != e; ++i) 1252 linkAppendingVarInit(AppendingVars[i]); 1253 1254 // Link in the function bodies that are defined in the source module into 1255 // DstM. 1256 for (Module::iterator SF = SrcM->begin(), E = SrcM->end(); SF != E; ++SF) { 1257 // Skip if not linking from source. 1258 if (DoNotLinkFromSource.count(SF)) continue; 1259 1260 Function *DF = cast<Function>(ValueMap[SF]); 1261 if (SF->hasPrefixData()) { 1262 // Link in the prefix data. 1263 DF->setPrefixData(MapValue( 1264 SF->getPrefixData(), ValueMap, RF_None, &TypeMap, &ValMaterializer)); 1265 } 1266 1267 // Skip if no body (function is external) or materialize. 1268 if (SF->isDeclaration()) { 1269 if (!SF->isMaterializable()) 1270 continue; 1271 if (SF->Materialize(&ErrorMsg)) 1272 return true; 1273 } 1274 1275 linkFunctionBody(DF, SF); 1276 SF->Dematerialize(); 1277 } 1278 1279 // Resolve all uses of aliases with aliasees. 1280 linkAliasBodies(); 1281 1282 // Remap all of the named MDNodes in Src into the DstM module. We do this 1283 // after linking GlobalValues so that MDNodes that reference GlobalValues 1284 // are properly remapped. 1285 linkNamedMDNodes(); 1286 1287 // Merge the module flags into the DstM module. 1288 if (linkModuleFlagsMetadata()) 1289 return true; 1290 1291 // Process vector of lazily linked in functions. 1292 bool LinkedInAnyFunctions; 1293 do { 1294 LinkedInAnyFunctions = false; 1295 1296 for(std::vector<Function*>::iterator I = LazilyLinkFunctions.begin(), 1297 E = LazilyLinkFunctions.end(); I != E; ++I) { 1298 Function *SF = *I; 1299 if (!SF) 1300 continue; 1301 1302 Function *DF = cast<Function>(ValueMap[SF]); 1303 if (SF->hasPrefixData()) { 1304 // Link in the prefix data. 1305 DF->setPrefixData(MapValue(SF->getPrefixData(), 1306 ValueMap, 1307 RF_None, 1308 &TypeMap, 1309 &ValMaterializer)); 1310 } 1311 1312 // Materialize if necessary. 1313 if (SF->isDeclaration()) { 1314 if (!SF->isMaterializable()) 1315 continue; 1316 if (SF->Materialize(&ErrorMsg)) 1317 return true; 1318 } 1319 1320 // Erase from vector *before* the function body is linked - linkFunctionBody could 1321 // invalidate I. 1322 LazilyLinkFunctions.erase(I); 1323 1324 // Link in function body. 1325 linkFunctionBody(DF, SF); 1326 SF->Dematerialize(); 1327 1328 // Set flag to indicate we may have more functions to lazily link in 1329 // since we linked in a function. 1330 LinkedInAnyFunctions = true; 1331 break; 1332 } 1333 } while (LinkedInAnyFunctions); 1334 1335 // Update the initializers in the DstM module now that all globals that may 1336 // be referenced are in DstM. 1337 linkGlobalInits(); 1338 1339 // Now that all of the types from the source are used, resolve any structs 1340 // copied over to the dest that didn't exist there. 1341 TypeMap.linkDefinedTypeBodies(); 1342 1343 return false; 1344} 1345 1346Linker::Linker(Module *M) : Composite(M) { 1347 TypeFinder StructTypes; 1348 StructTypes.run(*M, true); 1349 IdentifiedStructTypes.insert(StructTypes.begin(), StructTypes.end()); 1350} 1351 1352Linker::~Linker() { 1353} 1354 1355void Linker::deleteModule() { 1356 delete Composite; 1357 Composite = NULL; 1358} 1359 1360bool Linker::linkInModule(Module *Src, unsigned Mode, std::string *ErrorMsg) { 1361 ModuleLinker TheLinker(Composite, IdentifiedStructTypes, Src, Mode); 1362 if (TheLinker.run()) { 1363 if (ErrorMsg) 1364 *ErrorMsg = TheLinker.ErrorMsg; 1365 return true; 1366 } 1367 return false; 1368} 1369 1370//===----------------------------------------------------------------------===// 1371// LinkModules entrypoint. 1372//===----------------------------------------------------------------------===// 1373 1374/// LinkModules - This function links two modules together, with the resulting 1375/// Dest module modified to be the composite of the two input modules. If an 1376/// error occurs, true is returned and ErrorMsg (if not null) is set to indicate 1377/// the problem. Upon failure, the Dest module could be in a modified state, 1378/// and shouldn't be relied on to be consistent. 1379bool Linker::LinkModules(Module *Dest, Module *Src, unsigned Mode, 1380 std::string *ErrorMsg) { 1381 Linker L(Dest); 1382 return L.linkInModule(Src, Mode, ErrorMsg); 1383} 1384 1385//===----------------------------------------------------------------------===// 1386// C API. 1387//===----------------------------------------------------------------------===// 1388 1389LLVMBool LLVMLinkModules(LLVMModuleRef Dest, LLVMModuleRef Src, 1390 LLVMLinkerMode Mode, char **OutMessages) { 1391 std::string Messages; 1392 LLVMBool Result = Linker::LinkModules(unwrap(Dest), unwrap(Src), 1393 Mode, OutMessages? &Messages : 0); 1394 if (OutMessages) 1395 *OutMessages = strdup(Messages.c_str()); 1396 return Result; 1397} 1398