LinkModules.cpp revision cd7193fbce32e8ed3a63e8b76672cdf9956891ca
1//===- lib/Linker/LinkModules.cpp - Module Linker Implementation ----------===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file implements the LLVM module linker. 11// 12//===----------------------------------------------------------------------===// 13 14#include "llvm/Linker.h" 15#include "llvm/Constants.h" 16#include "llvm/DerivedTypes.h" 17#include "llvm/Instructions.h" 18#include "llvm/Module.h" 19#include "llvm/ADT/DenseSet.h" 20#include "llvm/ADT/Optional.h" 21#include "llvm/ADT/SetVector.h" 22#include "llvm/ADT/SmallPtrSet.h" 23#include "llvm/Support/Debug.h" 24#include "llvm/Support/Path.h" 25#include "llvm/Support/raw_ostream.h" 26#include "llvm/Transforms/Utils/Cloning.h" 27#include "llvm/Transforms/Utils/ValueMapper.h" 28#include <cctype> 29using namespace llvm; 30 31//===----------------------------------------------------------------------===// 32// TypeMap implementation. 33//===----------------------------------------------------------------------===// 34 35namespace { 36class TypeMapTy : public ValueMapTypeRemapper { 37 /// MappedTypes - This is a mapping from a source type to a destination type 38 /// to use. 39 DenseMap<Type*, Type*> MappedTypes; 40 41 /// SpeculativeTypes - When checking to see if two subgraphs are isomorphic, 42 /// we speculatively add types to MappedTypes, but keep track of them here in 43 /// case we need to roll back. 44 SmallVector<Type*, 16> SpeculativeTypes; 45 46 /// SrcDefinitionsToResolve - This is a list of non-opaque structs in the 47 /// source module that are mapped to an opaque struct in the destination 48 /// module. 49 SmallVector<StructType*, 16> SrcDefinitionsToResolve; 50 51 /// DstResolvedOpaqueTypes - This is the set of opaque types in the 52 /// destination modules who are getting a body from the source module. 53 SmallPtrSet<StructType*, 16> DstResolvedOpaqueTypes; 54public: 55 56 /// addTypeMapping - Indicate that the specified type in the destination 57 /// module is conceptually equivalent to the specified type in the source 58 /// module. 59 void addTypeMapping(Type *DstTy, Type *SrcTy); 60 61 /// linkDefinedTypeBodies - Produce a body for an opaque type in the dest 62 /// module from a type definition in the source module. 63 void linkDefinedTypeBodies(); 64 65 /// get - Return the mapped type to use for the specified input type from the 66 /// source module. 67 Type *get(Type *SrcTy); 68 69 FunctionType *get(FunctionType *T) {return cast<FunctionType>(get((Type*)T));} 70 71#ifndef NDEBUG 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#endif 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<ArrayType>(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} 241 242 243/// get - Return the mapped type to use for the specified input type from the 244/// source module. 245Type *TypeMapTy::get(Type *Ty) { 246 Type *Result = getImpl(Ty); 247 248 // If this caused a reference to any struct type, resolve it before returning. 249 if (!SrcDefinitionsToResolve.empty()) 250 linkDefinedTypeBodies(); 251 return Result; 252} 253 254/// getImpl - This is the recursive version of get(). 255Type *TypeMapTy::getImpl(Type *Ty) { 256 // If we already have an entry for this type, return it. 257 Type **Entry = &MappedTypes[Ty]; 258 if (*Entry) return *Entry; 259 260 // If this is not a named struct type, then just map all of the elements and 261 // then rebuild the type from inside out. 262 if (!isa<StructType>(Ty) || cast<StructType>(Ty)->isLiteral()) { 263 // If there are no element types to map, then the type is itself. This is 264 // true for the anonymous {} struct, things like 'float', integers, etc. 265 if (Ty->getNumContainedTypes() == 0) 266 return *Entry = Ty; 267 268 // Remap all of the elements, keeping track of whether any of them change. 269 bool AnyChange = false; 270 SmallVector<Type*, 4> ElementTypes; 271 ElementTypes.resize(Ty->getNumContainedTypes()); 272 for (unsigned i = 0, e = Ty->getNumContainedTypes(); i != e; ++i) { 273 ElementTypes[i] = getImpl(Ty->getContainedType(i)); 274 AnyChange |= ElementTypes[i] != Ty->getContainedType(i); 275 } 276 277 // If we found our type while recursively processing stuff, just use it. 278 Entry = &MappedTypes[Ty]; 279 if (*Entry) return *Entry; 280 281 // If all of the element types mapped directly over, then the type is usable 282 // as-is. 283 if (!AnyChange) 284 return *Entry = Ty; 285 286 // Otherwise, rebuild a modified type. 287 switch (Ty->getTypeID()) { 288 default: llvm_unreachable("unknown derived type to remap"); 289 case Type::ArrayTyID: 290 return *Entry = ArrayType::get(ElementTypes[0], 291 cast<ArrayType>(Ty)->getNumElements()); 292 case Type::VectorTyID: 293 return *Entry = VectorType::get(ElementTypes[0], 294 cast<VectorType>(Ty)->getNumElements()); 295 case Type::PointerTyID: 296 return *Entry = PointerType::get(ElementTypes[0], 297 cast<PointerType>(Ty)->getAddressSpace()); 298 case Type::FunctionTyID: 299 return *Entry = FunctionType::get(ElementTypes[0], 300 makeArrayRef(ElementTypes).slice(1), 301 cast<FunctionType>(Ty)->isVarArg()); 302 case Type::StructTyID: 303 // Note that this is only reached for anonymous structs. 304 return *Entry = StructType::get(Ty->getContext(), ElementTypes, 305 cast<StructType>(Ty)->isPacked()); 306 } 307 } 308 309 // Otherwise, this is an unmapped named struct. If the struct can be directly 310 // mapped over, just use it as-is. This happens in a case when the linked-in 311 // module has something like: 312 // %T = type {%T*, i32} 313 // @GV = global %T* null 314 // where T does not exist at all in the destination module. 315 // 316 // The other case we watch for is when the type is not in the destination 317 // module, but that it has to be rebuilt because it refers to something that 318 // is already mapped. For example, if the destination module has: 319 // %A = type { i32 } 320 // and the source module has something like 321 // %A' = type { i32 } 322 // %B = type { %A'* } 323 // @GV = global %B* null 324 // then we want to create a new type: "%B = type { %A*}" and have it take the 325 // pristine "%B" name from the source module. 326 // 327 // To determine which case this is, we have to recursively walk the type graph 328 // speculating that we'll be able to reuse it unmodified. Only if this is 329 // safe would we map the entire thing over. Because this is an optimization, 330 // and is not required for the prettiness of the linked module, we just skip 331 // it and always rebuild a type here. 332 StructType *STy = cast<StructType>(Ty); 333 334 // If the type is opaque, we can just use it directly. 335 if (STy->isOpaque()) 336 return *Entry = STy; 337 338 // Otherwise we create a new type and resolve its body later. This will be 339 // resolved by the top level of get(). 340 SrcDefinitionsToResolve.push_back(STy); 341 StructType *DTy = StructType::create(STy->getContext()); 342 DstResolvedOpaqueTypes.insert(DTy); 343 return *Entry = DTy; 344} 345 346 347 348//===----------------------------------------------------------------------===// 349// ModuleLinker implementation. 350//===----------------------------------------------------------------------===// 351 352namespace { 353 /// ModuleLinker - This is an implementation class for the LinkModules 354 /// function, which is the entrypoint for this file. 355 class ModuleLinker { 356 Module *DstM, *SrcM; 357 358 TypeMapTy TypeMap; 359 360 /// ValueMap - Mapping of values from what they used to be in Src, to what 361 /// they are now in DstM. ValueToValueMapTy is a ValueMap, which involves 362 /// some overhead due to the use of Value handles which the Linker doesn't 363 /// actually need, but this allows us to reuse the ValueMapper code. 364 ValueToValueMapTy ValueMap; 365 366 struct AppendingVarInfo { 367 GlobalVariable *NewGV; // New aggregate global in dest module. 368 Constant *DstInit; // Old initializer from dest module. 369 Constant *SrcInit; // Old initializer from src module. 370 }; 371 372 std::vector<AppendingVarInfo> AppendingVars; 373 374 unsigned Mode; // Mode to treat source module. 375 376 // Set of items not to link in from source. 377 SmallPtrSet<const Value*, 16> DoNotLinkFromSource; 378 379 // Vector of functions to lazily link in. 380 std::vector<Function*> LazilyLinkFunctions; 381 382 public: 383 std::string ErrorMsg; 384 385 ModuleLinker(Module *dstM, Module *srcM, unsigned mode) 386 : DstM(dstM), SrcM(srcM), Mode(mode) { } 387 388 bool run(); 389 390 private: 391 /// emitError - Helper method for setting a message and returning an error 392 /// code. 393 bool emitError(const Twine &Message) { 394 ErrorMsg = Message.str(); 395 return true; 396 } 397 398 /// getLinkageResult - This analyzes the two global values and determines 399 /// what the result will look like in the destination module. 400 bool getLinkageResult(GlobalValue *Dest, const GlobalValue *Src, 401 GlobalValue::LinkageTypes <, 402 GlobalValue::VisibilityTypes &Vis, 403 bool &LinkFromSrc); 404 405 /// getLinkedToGlobal - Given a global in the source module, return the 406 /// global in the destination module that is being linked to, if any. 407 GlobalValue *getLinkedToGlobal(GlobalValue *SrcGV) { 408 // If the source has no name it can't link. If it has local linkage, 409 // there is no name match-up going on. 410 if (!SrcGV->hasName() || SrcGV->hasLocalLinkage()) 411 return 0; 412 413 // Otherwise see if we have a match in the destination module's symtab. 414 GlobalValue *DGV = DstM->getNamedValue(SrcGV->getName()); 415 if (DGV == 0) return 0; 416 417 // If we found a global with the same name in the dest module, but it has 418 // internal linkage, we are really not doing any linkage here. 419 if (DGV->hasLocalLinkage()) 420 return 0; 421 422 // Otherwise, we do in fact link to the destination global. 423 return DGV; 424 } 425 426 void computeTypeMapping(); 427 bool categorizeModuleFlagNodes(const NamedMDNode *ModFlags, 428 DenseMap<MDString*, MDNode*> &ErrorNode, 429 DenseMap<MDString*, MDNode*> &WarningNode, 430 DenseMap<MDString*, MDNode*> &OverrideNode, 431 DenseMap<MDString*, 432 SmallSetVector<MDNode*, 8> > &RequireNodes, 433 SmallSetVector<MDString*, 16> &SeenIDs); 434 435 bool linkAppendingVarProto(GlobalVariable *DstGV, GlobalVariable *SrcGV); 436 bool linkGlobalProto(GlobalVariable *SrcGV); 437 bool linkFunctionProto(Function *SrcF); 438 bool linkAliasProto(GlobalAlias *SrcA); 439 bool linkModuleFlagsMetadata(); 440 441 void linkAppendingVarInit(const AppendingVarInfo &AVI); 442 void linkGlobalInits(); 443 void linkFunctionBody(Function *Dst, Function *Src); 444 void linkAliasBodies(); 445 void linkNamedMDNodes(); 446 }; 447} 448 449/// forceRenaming - The LLVM SymbolTable class autorenames globals that conflict 450/// in the symbol table. This is good for all clients except for us. Go 451/// through the trouble to force this back. 452static void forceRenaming(GlobalValue *GV, StringRef Name) { 453 // If the global doesn't force its name or if it already has the right name, 454 // there is nothing for us to do. 455 if (GV->hasLocalLinkage() || GV->getName() == Name) 456 return; 457 458 Module *M = GV->getParent(); 459 460 // If there is a conflict, rename the conflict. 461 if (GlobalValue *ConflictGV = M->getNamedValue(Name)) { 462 GV->takeName(ConflictGV); 463 ConflictGV->setName(Name); // This will cause ConflictGV to get renamed 464 assert(ConflictGV->getName() != Name && "forceRenaming didn't work"); 465 } else { 466 GV->setName(Name); // Force the name back 467 } 468} 469 470/// copyGVAttributes - copy additional attributes (those not needed to construct 471/// a GlobalValue) from the SrcGV to the DestGV. 472static void copyGVAttributes(GlobalValue *DestGV, const GlobalValue *SrcGV) { 473 // Use the maximum alignment, rather than just copying the alignment of SrcGV. 474 unsigned Alignment = std::max(DestGV->getAlignment(), SrcGV->getAlignment()); 475 DestGV->copyAttributesFrom(SrcGV); 476 DestGV->setAlignment(Alignment); 477 478 forceRenaming(DestGV, SrcGV->getName()); 479} 480 481static bool isLessConstraining(GlobalValue::VisibilityTypes a, 482 GlobalValue::VisibilityTypes b) { 483 if (a == GlobalValue::HiddenVisibility) 484 return false; 485 if (b == GlobalValue::HiddenVisibility) 486 return true; 487 if (a == GlobalValue::ProtectedVisibility) 488 return false; 489 if (b == GlobalValue::ProtectedVisibility) 490 return true; 491 return false; 492} 493 494/// getLinkageResult - This analyzes the two global values and determines what 495/// the result will look like in the destination module. In particular, it 496/// computes the resultant linkage type and visibility, computes whether the 497/// global in the source should be copied over to the destination (replacing 498/// the existing one), and computes whether this linkage is an error or not. 499bool ModuleLinker::getLinkageResult(GlobalValue *Dest, const GlobalValue *Src, 500 GlobalValue::LinkageTypes <, 501 GlobalValue::VisibilityTypes &Vis, 502 bool &LinkFromSrc) { 503 assert(Dest && "Must have two globals being queried"); 504 assert(!Src->hasLocalLinkage() && 505 "If Src has internal linkage, Dest shouldn't be set!"); 506 507 bool SrcIsDeclaration = Src->isDeclaration() && !Src->isMaterializable(); 508 bool DestIsDeclaration = Dest->isDeclaration(); 509 510 if (SrcIsDeclaration) { 511 // If Src is external or if both Src & Dest are external.. Just link the 512 // external globals, we aren't adding anything. 513 if (Src->hasDLLImportLinkage()) { 514 // If one of GVs has DLLImport linkage, result should be dllimport'ed. 515 if (DestIsDeclaration) { 516 LinkFromSrc = true; 517 LT = Src->getLinkage(); 518 } 519 } else if (Dest->hasExternalWeakLinkage()) { 520 // If the Dest is weak, use the source linkage. 521 LinkFromSrc = true; 522 LT = Src->getLinkage(); 523 } else { 524 LinkFromSrc = false; 525 LT = Dest->getLinkage(); 526 } 527 } else if (DestIsDeclaration && !Dest->hasDLLImportLinkage()) { 528 // If Dest is external but Src is not: 529 LinkFromSrc = true; 530 LT = Src->getLinkage(); 531 } else if (Src->isWeakForLinker()) { 532 // At this point we know that Dest has LinkOnce, External*, Weak, Common, 533 // or DLL* linkage. 534 if (Dest->hasExternalWeakLinkage() || 535 Dest->hasAvailableExternallyLinkage() || 536 (Dest->hasLinkOnceLinkage() && 537 (Src->hasWeakLinkage() || Src->hasCommonLinkage()))) { 538 LinkFromSrc = true; 539 LT = Src->getLinkage(); 540 } else { 541 LinkFromSrc = false; 542 LT = Dest->getLinkage(); 543 } 544 } else if (Dest->isWeakForLinker()) { 545 // At this point we know that Src has External* or DLL* linkage. 546 if (Src->hasExternalWeakLinkage()) { 547 LinkFromSrc = false; 548 LT = Dest->getLinkage(); 549 } else { 550 LinkFromSrc = true; 551 LT = GlobalValue::ExternalLinkage; 552 } 553 } else { 554 assert((Dest->hasExternalLinkage() || Dest->hasDLLImportLinkage() || 555 Dest->hasDLLExportLinkage() || Dest->hasExternalWeakLinkage()) && 556 (Src->hasExternalLinkage() || Src->hasDLLImportLinkage() || 557 Src->hasDLLExportLinkage() || Src->hasExternalWeakLinkage()) && 558 "Unexpected linkage type!"); 559 return emitError("Linking globals named '" + Src->getName() + 560 "': symbol multiply defined!"); 561 } 562 563 // Compute the visibility. We follow the rules in the System V Application 564 // Binary Interface. 565 Vis = isLessConstraining(Src->getVisibility(), Dest->getVisibility()) ? 566 Dest->getVisibility() : Src->getVisibility(); 567 return false; 568} 569 570/// computeTypeMapping - Loop over all of the linked values to compute type 571/// mappings. For example, if we link "extern Foo *x" and "Foo *x = NULL", then 572/// we have two struct types 'Foo' but one got renamed when the module was 573/// loaded into the same LLVMContext. 574void ModuleLinker::computeTypeMapping() { 575 // Incorporate globals. 576 for (Module::global_iterator I = SrcM->global_begin(), 577 E = SrcM->global_end(); I != E; ++I) { 578 GlobalValue *DGV = getLinkedToGlobal(I); 579 if (DGV == 0) continue; 580 581 if (!DGV->hasAppendingLinkage() || !I->hasAppendingLinkage()) { 582 TypeMap.addTypeMapping(DGV->getType(), I->getType()); 583 continue; 584 } 585 586 // Unify the element type of appending arrays. 587 ArrayType *DAT = cast<ArrayType>(DGV->getType()->getElementType()); 588 ArrayType *SAT = cast<ArrayType>(I->getType()->getElementType()); 589 TypeMap.addTypeMapping(DAT->getElementType(), SAT->getElementType()); 590 } 591 592 // Incorporate functions. 593 for (Module::iterator I = SrcM->begin(), E = SrcM->end(); I != E; ++I) { 594 if (GlobalValue *DGV = getLinkedToGlobal(I)) 595 TypeMap.addTypeMapping(DGV->getType(), I->getType()); 596 } 597 598 // Incorporate types by name, scanning all the types in the source module. 599 // At this point, the destination module may have a type "%foo = { i32 }" for 600 // example. When the source module got loaded into the same LLVMContext, if 601 // it had the same type, it would have been renamed to "%foo.42 = { i32 }". 602 // Though it isn't required for correctness, attempt to link these up to clean 603 // up the IR. 604 std::vector<StructType*> SrcStructTypes; 605 SrcM->findUsedStructTypes(SrcStructTypes); 606 607 SmallPtrSet<StructType*, 32> SrcStructTypesSet(SrcStructTypes.begin(), 608 SrcStructTypes.end()); 609 610 for (unsigned i = 0, e = SrcStructTypes.size(); i != e; ++i) { 611 StructType *ST = SrcStructTypes[i]; 612 if (!ST->hasName()) continue; 613 614 // Check to see if there is a dot in the name followed by a digit. 615 size_t DotPos = ST->getName().rfind('.'); 616 if (DotPos == 0 || DotPos == StringRef::npos || 617 ST->getName().back() == '.' || !isdigit(ST->getName()[DotPos+1])) 618 continue; 619 620 // Check to see if the destination module has a struct with the prefix name. 621 if (StructType *DST = DstM->getTypeByName(ST->getName().substr(0, DotPos))) 622 // Don't use it if this actually came from the source module. They're in 623 // the same LLVMContext after all. 624 if (!SrcStructTypesSet.count(DST)) 625 TypeMap.addTypeMapping(DST, ST); 626 } 627 628 // Don't bother incorporating aliases, they aren't generally typed well. 629 630 // Now that we have discovered all of the type equivalences, get a body for 631 // any 'opaque' types in the dest module that are now resolved. 632 TypeMap.linkDefinedTypeBodies(); 633} 634 635/// linkAppendingVarProto - If there were any appending global variables, link 636/// them together now. Return true on error. 637bool ModuleLinker::linkAppendingVarProto(GlobalVariable *DstGV, 638 GlobalVariable *SrcGV) { 639 640 if (!SrcGV->hasAppendingLinkage() || !DstGV->hasAppendingLinkage()) 641 return emitError("Linking globals named '" + SrcGV->getName() + 642 "': can only link appending global with another appending global!"); 643 644 ArrayType *DstTy = cast<ArrayType>(DstGV->getType()->getElementType()); 645 ArrayType *SrcTy = 646 cast<ArrayType>(TypeMap.get(SrcGV->getType()->getElementType())); 647 Type *EltTy = DstTy->getElementType(); 648 649 // Check to see that they two arrays agree on type. 650 if (EltTy != SrcTy->getElementType()) 651 return emitError("Appending variables with different element types!"); 652 if (DstGV->isConstant() != SrcGV->isConstant()) 653 return emitError("Appending variables linked with different const'ness!"); 654 655 if (DstGV->getAlignment() != SrcGV->getAlignment()) 656 return emitError( 657 "Appending variables with different alignment need to be linked!"); 658 659 if (DstGV->getVisibility() != SrcGV->getVisibility()) 660 return emitError( 661 "Appending variables with different visibility need to be linked!"); 662 663 if (DstGV->getSection() != SrcGV->getSection()) 664 return emitError( 665 "Appending variables with different section name need to be linked!"); 666 667 uint64_t NewSize = DstTy->getNumElements() + SrcTy->getNumElements(); 668 ArrayType *NewType = ArrayType::get(EltTy, NewSize); 669 670 // Create the new global variable. 671 GlobalVariable *NG = 672 new GlobalVariable(*DstGV->getParent(), NewType, SrcGV->isConstant(), 673 DstGV->getLinkage(), /*init*/0, /*name*/"", DstGV, 674 DstGV->isThreadLocal(), 675 DstGV->getType()->getAddressSpace()); 676 677 // Propagate alignment, visibility and section info. 678 copyGVAttributes(NG, DstGV); 679 680 AppendingVarInfo AVI; 681 AVI.NewGV = NG; 682 AVI.DstInit = DstGV->getInitializer(); 683 AVI.SrcInit = SrcGV->getInitializer(); 684 AppendingVars.push_back(AVI); 685 686 // Replace any uses of the two global variables with uses of the new 687 // global. 688 ValueMap[SrcGV] = ConstantExpr::getBitCast(NG, TypeMap.get(SrcGV->getType())); 689 690 DstGV->replaceAllUsesWith(ConstantExpr::getBitCast(NG, DstGV->getType())); 691 DstGV->eraseFromParent(); 692 693 // Track the source variable so we don't try to link it. 694 DoNotLinkFromSource.insert(SrcGV); 695 696 return false; 697} 698 699/// linkGlobalProto - Loop through the global variables in the src module and 700/// merge them into the dest module. 701bool ModuleLinker::linkGlobalProto(GlobalVariable *SGV) { 702 GlobalValue *DGV = getLinkedToGlobal(SGV); 703 llvm::Optional<GlobalValue::VisibilityTypes> NewVisibility; 704 705 if (DGV) { 706 // Concatenation of appending linkage variables is magic and handled later. 707 if (DGV->hasAppendingLinkage() || SGV->hasAppendingLinkage()) 708 return linkAppendingVarProto(cast<GlobalVariable>(DGV), SGV); 709 710 // Determine whether linkage of these two globals follows the source 711 // module's definition or the destination module's definition. 712 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; 713 GlobalValue::VisibilityTypes NV; 714 bool LinkFromSrc = false; 715 if (getLinkageResult(DGV, SGV, NewLinkage, NV, LinkFromSrc)) 716 return true; 717 NewVisibility = NV; 718 719 // If we're not linking from the source, then keep the definition that we 720 // have. 721 if (!LinkFromSrc) { 722 // Special case for const propagation. 723 if (GlobalVariable *DGVar = dyn_cast<GlobalVariable>(DGV)) 724 if (DGVar->isDeclaration() && SGV->isConstant() && !DGVar->isConstant()) 725 DGVar->setConstant(true); 726 727 // Set calculated linkage and visibility. 728 DGV->setLinkage(NewLinkage); 729 DGV->setVisibility(*NewVisibility); 730 731 // Make sure to remember this mapping. 732 ValueMap[SGV] = ConstantExpr::getBitCast(DGV,TypeMap.get(SGV->getType())); 733 734 // Track the source global so that we don't attempt to copy it over when 735 // processing global initializers. 736 DoNotLinkFromSource.insert(SGV); 737 738 return false; 739 } 740 } 741 742 // No linking to be performed or linking from the source: simply create an 743 // identical version of the symbol over in the dest module... the 744 // initializer will be filled in later by LinkGlobalInits. 745 GlobalVariable *NewDGV = 746 new GlobalVariable(*DstM, TypeMap.get(SGV->getType()->getElementType()), 747 SGV->isConstant(), SGV->getLinkage(), /*init*/0, 748 SGV->getName(), /*insertbefore*/0, 749 SGV->isThreadLocal(), 750 SGV->getType()->getAddressSpace()); 751 // Propagate alignment, visibility and section info. 752 copyGVAttributes(NewDGV, SGV); 753 if (NewVisibility) 754 NewDGV->setVisibility(*NewVisibility); 755 756 if (DGV) { 757 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDGV, DGV->getType())); 758 DGV->eraseFromParent(); 759 } 760 761 // Make sure to remember this mapping. 762 ValueMap[SGV] = NewDGV; 763 return false; 764} 765 766/// linkFunctionProto - Link the function in the source module into the 767/// destination module if needed, setting up mapping information. 768bool ModuleLinker::linkFunctionProto(Function *SF) { 769 GlobalValue *DGV = getLinkedToGlobal(SF); 770 llvm::Optional<GlobalValue::VisibilityTypes> NewVisibility; 771 772 if (DGV) { 773 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; 774 bool LinkFromSrc = false; 775 GlobalValue::VisibilityTypes NV; 776 if (getLinkageResult(DGV, SF, NewLinkage, NV, LinkFromSrc)) 777 return true; 778 NewVisibility = NV; 779 780 if (!LinkFromSrc) { 781 // Set calculated linkage 782 DGV->setLinkage(NewLinkage); 783 DGV->setVisibility(*NewVisibility); 784 785 // Make sure to remember this mapping. 786 ValueMap[SF] = ConstantExpr::getBitCast(DGV, TypeMap.get(SF->getType())); 787 788 // Track the function from the source module so we don't attempt to remap 789 // it. 790 DoNotLinkFromSource.insert(SF); 791 792 return false; 793 } 794 } 795 796 // If there is no linkage to be performed or we are linking from the source, 797 // bring SF over. 798 Function *NewDF = Function::Create(TypeMap.get(SF->getFunctionType()), 799 SF->getLinkage(), SF->getName(), DstM); 800 copyGVAttributes(NewDF, SF); 801 if (NewVisibility) 802 NewDF->setVisibility(*NewVisibility); 803 804 if (DGV) { 805 // Any uses of DF need to change to NewDF, with cast. 806 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDF, DGV->getType())); 807 DGV->eraseFromParent(); 808 } else { 809 // Internal, LO_ODR, or LO linkage - stick in set to ignore and lazily link. 810 if (SF->hasLocalLinkage() || SF->hasLinkOnceLinkage() || 811 SF->hasAvailableExternallyLinkage()) { 812 DoNotLinkFromSource.insert(SF); 813 LazilyLinkFunctions.push_back(SF); 814 } 815 } 816 817 ValueMap[SF] = NewDF; 818 return false; 819} 820 821/// LinkAliasProto - Set up prototypes for any aliases that come over from the 822/// source module. 823bool ModuleLinker::linkAliasProto(GlobalAlias *SGA) { 824 GlobalValue *DGV = getLinkedToGlobal(SGA); 825 llvm::Optional<GlobalValue::VisibilityTypes> NewVisibility; 826 827 if (DGV) { 828 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; 829 GlobalValue::VisibilityTypes NV; 830 bool LinkFromSrc = false; 831 if (getLinkageResult(DGV, SGA, NewLinkage, NV, LinkFromSrc)) 832 return true; 833 NewVisibility = NV; 834 835 if (!LinkFromSrc) { 836 // Set calculated linkage. 837 DGV->setLinkage(NewLinkage); 838 DGV->setVisibility(*NewVisibility); 839 840 // Make sure to remember this mapping. 841 ValueMap[SGA] = ConstantExpr::getBitCast(DGV,TypeMap.get(SGA->getType())); 842 843 // Track the alias from the source module so we don't attempt to remap it. 844 DoNotLinkFromSource.insert(SGA); 845 846 return false; 847 } 848 } 849 850 // If there is no linkage to be performed or we're linking from the source, 851 // bring over SGA. 852 GlobalAlias *NewDA = new GlobalAlias(TypeMap.get(SGA->getType()), 853 SGA->getLinkage(), SGA->getName(), 854 /*aliasee*/0, DstM); 855 copyGVAttributes(NewDA, SGA); 856 if (NewVisibility) 857 NewDA->setVisibility(*NewVisibility); 858 859 if (DGV) { 860 // Any uses of DGV need to change to NewDA, with cast. 861 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDA, DGV->getType())); 862 DGV->eraseFromParent(); 863 } 864 865 ValueMap[SGA] = NewDA; 866 return false; 867} 868 869static void getArrayElements(Constant *C, SmallVectorImpl<Constant*> &Dest) { 870 unsigned NumElements = cast<ArrayType>(C->getType())->getNumElements(); 871 872 for (unsigned i = 0; i != NumElements; ++i) 873 Dest.push_back(C->getAggregateElement(i)); 874} 875 876void ModuleLinker::linkAppendingVarInit(const AppendingVarInfo &AVI) { 877 // Merge the initializer. 878 SmallVector<Constant*, 16> Elements; 879 getArrayElements(AVI.DstInit, Elements); 880 881 Constant *SrcInit = MapValue(AVI.SrcInit, ValueMap, RF_None, &TypeMap); 882 getArrayElements(SrcInit, Elements); 883 884 ArrayType *NewType = cast<ArrayType>(AVI.NewGV->getType()->getElementType()); 885 AVI.NewGV->setInitializer(ConstantArray::get(NewType, Elements)); 886} 887 888/// linkGlobalInits - Update the initializers in the Dest module now that all 889/// globals that may be referenced are in Dest. 890void ModuleLinker::linkGlobalInits() { 891 // Loop over all of the globals in the src module, mapping them over as we go 892 for (Module::const_global_iterator I = SrcM->global_begin(), 893 E = SrcM->global_end(); I != E; ++I) { 894 895 // Only process initialized GV's or ones not already in dest. 896 if (!I->hasInitializer() || DoNotLinkFromSource.count(I)) continue; 897 898 // Grab destination global variable. 899 GlobalVariable *DGV = cast<GlobalVariable>(ValueMap[I]); 900 // Figure out what the initializer looks like in the dest module. 901 DGV->setInitializer(MapValue(I->getInitializer(), ValueMap, 902 RF_None, &TypeMap)); 903 } 904} 905 906/// linkFunctionBody - Copy the source function over into the dest function and 907/// fix up references to values. At this point we know that Dest is an external 908/// function, and that Src is not. 909void ModuleLinker::linkFunctionBody(Function *Dst, Function *Src) { 910 assert(Src && Dst && Dst->isDeclaration() && !Src->isDeclaration()); 911 912 // Go through and convert function arguments over, remembering the mapping. 913 Function::arg_iterator DI = Dst->arg_begin(); 914 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end(); 915 I != E; ++I, ++DI) { 916 DI->setName(I->getName()); // Copy the name over. 917 918 // Add a mapping to our mapping. 919 ValueMap[I] = DI; 920 } 921 922 if (Mode == Linker::DestroySource) { 923 // Splice the body of the source function into the dest function. 924 Dst->getBasicBlockList().splice(Dst->end(), Src->getBasicBlockList()); 925 926 // At this point, all of the instructions and values of the function are now 927 // copied over. The only problem is that they are still referencing values in 928 // the Source function as operands. Loop through all of the operands of the 929 // functions and patch them up to point to the local versions. 930 for (Function::iterator BB = Dst->begin(), BE = Dst->end(); BB != BE; ++BB) 931 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) 932 RemapInstruction(I, ValueMap, RF_IgnoreMissingEntries, &TypeMap); 933 934 } else { 935 // Clone the body of the function into the dest function. 936 SmallVector<ReturnInst*, 8> Returns; // Ignore returns. 937 CloneFunctionInto(Dst, Src, ValueMap, false, Returns, "", NULL, &TypeMap); 938 } 939 940 // There is no need to map the arguments anymore. 941 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end(); 942 I != E; ++I) 943 ValueMap.erase(I); 944 945} 946 947/// linkAliasBodies - Insert all of the aliases in Src into the Dest module. 948void ModuleLinker::linkAliasBodies() { 949 for (Module::alias_iterator I = SrcM->alias_begin(), E = SrcM->alias_end(); 950 I != E; ++I) { 951 if (DoNotLinkFromSource.count(I)) 952 continue; 953 if (Constant *Aliasee = I->getAliasee()) { 954 GlobalAlias *DA = cast<GlobalAlias>(ValueMap[I]); 955 DA->setAliasee(MapValue(Aliasee, ValueMap, RF_None, &TypeMap)); 956 } 957 } 958} 959 960/// linkNamedMDNodes - Insert all of the named MDNodes in Src into the Dest 961/// module. 962void ModuleLinker::linkNamedMDNodes() { 963 const NamedMDNode *SrcModFlags = SrcM->getModuleFlagsMetadata(); 964 for (Module::const_named_metadata_iterator I = SrcM->named_metadata_begin(), 965 E = SrcM->named_metadata_end(); I != E; ++I) { 966 // Don't link module flags here. Do them separately. 967 if (&*I == SrcModFlags) continue; 968 NamedMDNode *DestNMD = DstM->getOrInsertNamedMetadata(I->getName()); 969 // Add Src elements into Dest node. 970 for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) 971 DestNMD->addOperand(MapValue(I->getOperand(i), ValueMap, 972 RF_None, &TypeMap)); 973 } 974} 975 976/// categorizeModuleFlagNodes - Categorize the module flags according to their 977/// type: Error, Warning, Override, and Require. 978bool ModuleLinker:: 979categorizeModuleFlagNodes(const NamedMDNode *ModFlags, 980 DenseMap<MDString*, MDNode*> &ErrorNode, 981 DenseMap<MDString*, MDNode*> &WarningNode, 982 DenseMap<MDString*, MDNode*> &OverrideNode, 983 DenseMap<MDString*, 984 SmallSetVector<MDNode*, 8> > &RequireNodes, 985 SmallSetVector<MDString*, 16> &SeenIDs) { 986 bool HasErr = false; 987 988 for (unsigned I = 0, E = ModFlags->getNumOperands(); I != E; ++I) { 989 MDNode *Op = ModFlags->getOperand(I); 990 assert(Op->getNumOperands() == 3 && "Invalid module flag metadata!"); 991 assert(isa<ConstantInt>(Op->getOperand(0)) && 992 "Module flag's first operand must be an integer!"); 993 assert(isa<MDString>(Op->getOperand(1)) && 994 "Module flag's second operand must be an MDString!"); 995 996 ConstantInt *Behavior = cast<ConstantInt>(Op->getOperand(0)); 997 MDString *ID = cast<MDString>(Op->getOperand(1)); 998 Value *Val = Op->getOperand(2); 999 switch (Behavior->getZExtValue()) { 1000 default: 1001 assert(false && "Invalid behavior in module flag metadata!"); 1002 break; 1003 case Module::Error: { 1004 MDNode *&ErrNode = ErrorNode[ID]; 1005 if (!ErrNode) ErrNode = Op; 1006 if (ErrNode->getOperand(2) != Val) 1007 HasErr = emitError("linking module flags '" + ID->getString() + 1008 "': IDs have conflicting values"); 1009 break; 1010 } 1011 case Module::Warning: { 1012 MDNode *&WarnNode = WarningNode[ID]; 1013 if (!WarnNode) WarnNode = Op; 1014 if (WarnNode->getOperand(2) != Val) 1015 errs() << "WARNING: linking module flags '" << ID->getString() 1016 << "': IDs have conflicting values"; 1017 break; 1018 } 1019 case Module::Require: RequireNodes[ID].insert(Op); break; 1020 case Module::Override: { 1021 MDNode *&OvrNode = OverrideNode[ID]; 1022 if (!OvrNode) OvrNode = Op; 1023 if (OvrNode->getOperand(2) != Val) 1024 HasErr = emitError("linking module flags '" + ID->getString() + 1025 "': IDs have conflicting override values"); 1026 break; 1027 } 1028 } 1029 1030 SeenIDs.insert(ID); 1031 } 1032 1033 return HasErr; 1034} 1035 1036/// linkModuleFlagsMetadata - Merge the linker flags in Src into the Dest 1037/// module. 1038bool ModuleLinker::linkModuleFlagsMetadata() { 1039 const NamedMDNode *SrcModFlags = SrcM->getModuleFlagsMetadata(); 1040 if (!SrcModFlags) return false; 1041 1042 NamedMDNode *DstModFlags = DstM->getOrInsertModuleFlagsMetadata(); 1043 1044 // If the destination module doesn't have module flags yet, then just copy 1045 // over the source module's flags. 1046 if (DstModFlags->getNumOperands() == 0) { 1047 for (unsigned I = 0, E = SrcModFlags->getNumOperands(); I != E; ++I) 1048 DstModFlags->addOperand(SrcModFlags->getOperand(I)); 1049 1050 return false; 1051 } 1052 1053 bool HasErr = false; 1054 1055 // Otherwise, we have to merge them based on their behaviors. First, 1056 // categorize all of the nodes in the modules' module flags. If an error or 1057 // warning occurs, then emit the appropriate message(s). 1058 DenseMap<MDString*, MDNode*> ErrorNode; 1059 DenseMap<MDString*, MDNode*> WarningNode; 1060 DenseMap<MDString*, MDNode*> OverrideNode; 1061 DenseMap<MDString*, SmallSetVector<MDNode*, 8> > RequireNodes; 1062 SmallSetVector<MDString*, 16> SeenIDs; 1063 1064 HasErr |= categorizeModuleFlagNodes(SrcModFlags, ErrorNode, WarningNode, 1065 OverrideNode, RequireNodes, SeenIDs); 1066 HasErr |= categorizeModuleFlagNodes(DstModFlags, ErrorNode, WarningNode, 1067 OverrideNode, RequireNodes, SeenIDs); 1068 1069 // Check that there isn't both an error and warning node for a flag. 1070 for (SmallSetVector<MDString*, 16>::iterator 1071 I = SeenIDs.begin(), E = SeenIDs.end(); I != E; ++I) { 1072 MDString *ID = *I; 1073 if (ErrorNode[ID] && WarningNode[ID]) 1074 HasErr = emitError("linking module flags '" + ID->getString() + 1075 "': IDs have conflicting behaviors"); 1076 } 1077 1078 // Early exit if we had an error. 1079 if (HasErr) return true; 1080 1081 // Get the destination's module flags ready for new operands. 1082 DstModFlags->dropAllReferences(); 1083 1084 // Add all of the module flags to the destination module. 1085 DenseMap<MDString*, SmallVector<MDNode*, 4> > AddedNodes; 1086 for (SmallSetVector<MDString*, 16>::iterator 1087 I = SeenIDs.begin(), E = SeenIDs.end(); I != E; ++I) { 1088 MDString *ID = *I; 1089 if (OverrideNode[ID]) { 1090 DstModFlags->addOperand(OverrideNode[ID]); 1091 AddedNodes[ID].push_back(OverrideNode[ID]); 1092 } else if (ErrorNode[ID]) { 1093 DstModFlags->addOperand(ErrorNode[ID]); 1094 AddedNodes[ID].push_back(ErrorNode[ID]); 1095 } else if (WarningNode[ID]) { 1096 DstModFlags->addOperand(WarningNode[ID]); 1097 AddedNodes[ID].push_back(WarningNode[ID]); 1098 } 1099 1100 for (SmallSetVector<MDNode*, 8>::iterator 1101 II = RequireNodes[ID].begin(), IE = RequireNodes[ID].end(); 1102 II != IE; ++II) 1103 DstModFlags->addOperand(*II); 1104 } 1105 1106 // Now check that all of the requirements have been satisfied. 1107 for (SmallSetVector<MDString*, 16>::iterator 1108 I = SeenIDs.begin(), E = SeenIDs.end(); I != E; ++I) { 1109 MDString *ID = *I; 1110 SmallSetVector<MDNode*, 8> &Set = RequireNodes[ID]; 1111 1112 for (SmallSetVector<MDNode*, 8>::iterator 1113 II = Set.begin(), IE = Set.end(); II != IE; ++II) { 1114 MDNode *Node = *II; 1115 assert(isa<MDNode>(Node->getOperand(2)) && 1116 "Module flag's third operand must be an MDNode!"); 1117 MDNode *Val = cast<MDNode>(Node->getOperand(2)); 1118 1119 MDString *ReqID = cast<MDString>(Val->getOperand(0)); 1120 Value *ReqVal = Val->getOperand(1); 1121 1122 bool HasValue = false; 1123 for (SmallVectorImpl<MDNode*>::iterator 1124 RI = AddedNodes[ReqID].begin(), RE = AddedNodes[ReqID].end(); 1125 RI != RE; ++RI) { 1126 MDNode *ReqNode = *RI; 1127 if (ReqNode->getOperand(2) == ReqVal) { 1128 HasValue = true; 1129 break; 1130 } 1131 } 1132 1133 if (!HasValue) 1134 HasErr = emitError("linking module flags '" + ReqID->getString() + 1135 "': does not have the required value"); 1136 } 1137 } 1138 1139 return HasErr; 1140} 1141 1142bool ModuleLinker::run() { 1143 assert(DstM && "Null destination module"); 1144 assert(SrcM && "Null source module"); 1145 1146 // Inherit the target data from the source module if the destination module 1147 // doesn't have one already. 1148 if (DstM->getDataLayout().empty() && !SrcM->getDataLayout().empty()) 1149 DstM->setDataLayout(SrcM->getDataLayout()); 1150 1151 // Copy the target triple from the source to dest if the dest's is empty. 1152 if (DstM->getTargetTriple().empty() && !SrcM->getTargetTriple().empty()) 1153 DstM->setTargetTriple(SrcM->getTargetTriple()); 1154 1155 if (!SrcM->getDataLayout().empty() && !DstM->getDataLayout().empty() && 1156 SrcM->getDataLayout() != DstM->getDataLayout()) 1157 errs() << "WARNING: Linking two modules of different data layouts!\n"; 1158 if (!SrcM->getTargetTriple().empty() && 1159 DstM->getTargetTriple() != SrcM->getTargetTriple()) { 1160 errs() << "WARNING: Linking two modules of different target triples: "; 1161 if (!SrcM->getModuleIdentifier().empty()) 1162 errs() << SrcM->getModuleIdentifier() << ": "; 1163 errs() << "'" << SrcM->getTargetTriple() << "' and '" 1164 << DstM->getTargetTriple() << "'\n"; 1165 } 1166 1167 // Append the module inline asm string. 1168 if (!SrcM->getModuleInlineAsm().empty()) { 1169 if (DstM->getModuleInlineAsm().empty()) 1170 DstM->setModuleInlineAsm(SrcM->getModuleInlineAsm()); 1171 else 1172 DstM->setModuleInlineAsm(DstM->getModuleInlineAsm()+"\n"+ 1173 SrcM->getModuleInlineAsm()); 1174 } 1175 1176 // Update the destination module's dependent libraries list with the libraries 1177 // from the source module. There's no opportunity for duplicates here as the 1178 // Module ensures that duplicate insertions are discarded. 1179 for (Module::lib_iterator SI = SrcM->lib_begin(), SE = SrcM->lib_end(); 1180 SI != SE; ++SI) 1181 DstM->addLibrary(*SI); 1182 1183 // If the source library's module id is in the dependent library list of the 1184 // destination library, remove it since that module is now linked in. 1185 StringRef ModuleId = SrcM->getModuleIdentifier(); 1186 if (!ModuleId.empty()) 1187 DstM->removeLibrary(sys::path::stem(ModuleId)); 1188 1189 // Loop over all of the linked values to compute type mappings. 1190 computeTypeMapping(); 1191 1192 // Insert all of the globals in src into the DstM module... without linking 1193 // initializers (which could refer to functions not yet mapped over). 1194 for (Module::global_iterator I = SrcM->global_begin(), 1195 E = SrcM->global_end(); I != E; ++I) 1196 if (linkGlobalProto(I)) 1197 return true; 1198 1199 // Link the functions together between the two modules, without doing function 1200 // bodies... this just adds external function prototypes to the DstM 1201 // function... We do this so that when we begin processing function bodies, 1202 // all of the global values that may be referenced are available in our 1203 // ValueMap. 1204 for (Module::iterator I = SrcM->begin(), E = SrcM->end(); I != E; ++I) 1205 if (linkFunctionProto(I)) 1206 return true; 1207 1208 // If there were any aliases, link them now. 1209 for (Module::alias_iterator I = SrcM->alias_begin(), 1210 E = SrcM->alias_end(); I != E; ++I) 1211 if (linkAliasProto(I)) 1212 return true; 1213 1214 for (unsigned i = 0, e = AppendingVars.size(); i != e; ++i) 1215 linkAppendingVarInit(AppendingVars[i]); 1216 1217 // Update the initializers in the DstM module now that all globals that may 1218 // be referenced are in DstM. 1219 linkGlobalInits(); 1220 1221 // Link in the function bodies that are defined in the source module into 1222 // DstM. 1223 for (Module::iterator SF = SrcM->begin(), E = SrcM->end(); SF != E; ++SF) { 1224 // Skip if not linking from source. 1225 if (DoNotLinkFromSource.count(SF)) continue; 1226 1227 // Skip if no body (function is external) or materialize. 1228 if (SF->isDeclaration()) { 1229 if (!SF->isMaterializable()) 1230 continue; 1231 if (SF->Materialize(&ErrorMsg)) 1232 return true; 1233 } 1234 1235 linkFunctionBody(cast<Function>(ValueMap[SF]), SF); 1236 } 1237 1238 // Resolve all uses of aliases with aliasees. 1239 linkAliasBodies(); 1240 1241 // Remap all of the named MDNodes in Src into the DstM module. We do this 1242 // after linking GlobalValues so that MDNodes that reference GlobalValues 1243 // are properly remapped. 1244 linkNamedMDNodes(); 1245 1246 // Merge the module flags into the DstM module. 1247 if (linkModuleFlagsMetadata()) 1248 return true; 1249 1250 // Process vector of lazily linked in functions. 1251 bool LinkedInAnyFunctions; 1252 do { 1253 LinkedInAnyFunctions = false; 1254 1255 for(std::vector<Function*>::iterator I = LazilyLinkFunctions.begin(), 1256 E = LazilyLinkFunctions.end(); I != E; ++I) { 1257 if (!*I) 1258 continue; 1259 1260 Function *SF = *I; 1261 Function *DF = cast<Function>(ValueMap[SF]); 1262 1263 if (!DF->use_empty()) { 1264 1265 // Materialize if necessary. 1266 if (SF->isDeclaration()) { 1267 if (!SF->isMaterializable()) 1268 continue; 1269 if (SF->Materialize(&ErrorMsg)) 1270 return true; 1271 } 1272 1273 // Link in function body. 1274 linkFunctionBody(DF, SF); 1275 1276 // "Remove" from vector by setting the element to 0. 1277 *I = 0; 1278 1279 // Set flag to indicate we may have more functions to lazily link in 1280 // since we linked in a function. 1281 LinkedInAnyFunctions = true; 1282 } 1283 } 1284 } while (LinkedInAnyFunctions); 1285 1286 // Remove any prototypes of functions that were not actually linked in. 1287 for(std::vector<Function*>::iterator I = LazilyLinkFunctions.begin(), 1288 E = LazilyLinkFunctions.end(); I != E; ++I) { 1289 if (!*I) 1290 continue; 1291 1292 Function *SF = *I; 1293 Function *DF = cast<Function>(ValueMap[SF]); 1294 if (DF->use_empty()) 1295 DF->eraseFromParent(); 1296 } 1297 1298 // Now that all of the types from the source are used, resolve any structs 1299 // copied over to the dest that didn't exist there. 1300 TypeMap.linkDefinedTypeBodies(); 1301 1302 return false; 1303} 1304 1305//===----------------------------------------------------------------------===// 1306// LinkModules entrypoint. 1307//===----------------------------------------------------------------------===// 1308 1309/// LinkModules - This function links two modules together, with the resulting 1310/// left module modified to be the composite of the two input modules. If an 1311/// error occurs, true is returned and ErrorMsg (if not null) is set to indicate 1312/// the problem. Upon failure, the Dest module could be in a modified state, 1313/// and shouldn't be relied on to be consistent. 1314bool Linker::LinkModules(Module *Dest, Module *Src, unsigned Mode, 1315 std::string *ErrorMsg) { 1316 ModuleLinker TheLinker(Dest, Src, Mode); 1317 if (TheLinker.run()) { 1318 if (ErrorMsg) *ErrorMsg = TheLinker.ErrorMsg; 1319 return true; 1320 } 1321 1322 return false; 1323} 1324