LinkModules.cpp revision c68d127b2c5a233c5e3f9dd59ca4ab335419d9dd
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/raw_ostream.h" 24#include "llvm/Support/Path.h" 25#include "llvm/Transforms/Utils/Cloning.h" 26#include "llvm/Transforms/Utils/ValueMapper.h" 27using namespace llvm; 28 29//===----------------------------------------------------------------------===// 30// TypeMap implementation. 31//===----------------------------------------------------------------------===// 32 33namespace { 34class TypeMapTy : public ValueMapTypeRemapper { 35 /// MappedTypes - This is a mapping from a source type to a destination type 36 /// to use. 37 DenseMap<Type*, Type*> MappedTypes; 38 39 /// SpeculativeTypes - When checking to see if two subgraphs are isomorphic, 40 /// we speculatively add types to MappedTypes, but keep track of them here in 41 /// case we need to roll back. 42 SmallVector<Type*, 16> SpeculativeTypes; 43 44 /// SrcDefinitionsToResolve - This is a list of non-opaque structs in the 45 /// source module that are mapped to an opaque struct in the destination 46 /// module. 47 SmallVector<StructType*, 16> SrcDefinitionsToResolve; 48 49 /// DstResolvedOpaqueTypes - This is the set of opaque types in the 50 /// destination modules who are getting a body from the source module. 51 SmallPtrSet<StructType*, 16> DstResolvedOpaqueTypes; 52public: 53 54 /// addTypeMapping - Indicate that the specified type in the destination 55 /// module is conceptually equivalent to the specified type in the source 56 /// module. 57 void addTypeMapping(Type *DstTy, Type *SrcTy); 58 59 /// linkDefinedTypeBodies - Produce a body for an opaque type in the dest 60 /// module from a type definition in the source module. 61 void linkDefinedTypeBodies(); 62 63 /// get - Return the mapped type to use for the specified input type from the 64 /// source module. 65 Type *get(Type *SrcTy); 66 67 FunctionType *get(FunctionType *T) {return cast<FunctionType>(get((Type*)T));} 68 69private: 70 Type *getImpl(Type *T); 71 /// remapType - Implement the ValueMapTypeRemapper interface. 72 Type *remapType(Type *SrcTy) { 73 return get(SrcTy); 74 } 75 76 bool areTypesIsomorphic(Type *DstTy, Type *SrcTy); 77}; 78} 79 80void TypeMapTy::addTypeMapping(Type *DstTy, Type *SrcTy) { 81 Type *&Entry = MappedTypes[SrcTy]; 82 if (Entry) return; 83 84 if (DstTy == SrcTy) { 85 Entry = DstTy; 86 return; 87 } 88 89 // Check to see if these types are recursively isomorphic and establish a 90 // mapping between them if so. 91 if (!areTypesIsomorphic(DstTy, SrcTy)) { 92 // Oops, they aren't isomorphic. Just discard this request by rolling out 93 // any speculative mappings we've established. 94 for (unsigned i = 0, e = SpeculativeTypes.size(); i != e; ++i) 95 MappedTypes.erase(SpeculativeTypes[i]); 96 } 97 SpeculativeTypes.clear(); 98} 99 100/// areTypesIsomorphic - Recursively walk this pair of types, returning true 101/// if they are isomorphic, false if they are not. 102bool TypeMapTy::areTypesIsomorphic(Type *DstTy, Type *SrcTy) { 103 // Two types with differing kinds are clearly not isomorphic. 104 if (DstTy->getTypeID() != SrcTy->getTypeID()) return false; 105 106 // If we have an entry in the MappedTypes table, then we have our answer. 107 Type *&Entry = MappedTypes[SrcTy]; 108 if (Entry) 109 return Entry == DstTy; 110 111 // Two identical types are clearly isomorphic. Remember this 112 // non-speculatively. 113 if (DstTy == SrcTy) { 114 Entry = DstTy; 115 return true; 116 } 117 118 // Okay, we have two types with identical kinds that we haven't seen before. 119 120 // If this is an opaque struct type, special case it. 121 if (StructType *SSTy = dyn_cast<StructType>(SrcTy)) { 122 // Mapping an opaque type to any struct, just keep the dest struct. 123 if (SSTy->isOpaque()) { 124 Entry = DstTy; 125 SpeculativeTypes.push_back(SrcTy); 126 return true; 127 } 128 129 // Mapping a non-opaque source type to an opaque dest. If this is the first 130 // type that we're mapping onto this destination type then we succeed. Keep 131 // the dest, but fill it in later. This doesn't need to be speculative. If 132 // this is the second (different) type that we're trying to map onto the 133 // same opaque type then we fail. 134 if (cast<StructType>(DstTy)->isOpaque()) { 135 // We can only map one source type onto the opaque destination type. 136 if (!DstResolvedOpaqueTypes.insert(cast<StructType>(DstTy))) 137 return false; 138 SrcDefinitionsToResolve.push_back(SSTy); 139 Entry = DstTy; 140 return true; 141 } 142 } 143 144 // If the number of subtypes disagree between the two types, then we fail. 145 if (SrcTy->getNumContainedTypes() != DstTy->getNumContainedTypes()) 146 return false; 147 148 // Fail if any of the extra properties (e.g. array size) of the type disagree. 149 if (isa<IntegerType>(DstTy)) 150 return false; // bitwidth disagrees. 151 if (PointerType *PT = dyn_cast<PointerType>(DstTy)) { 152 if (PT->getAddressSpace() != cast<PointerType>(SrcTy)->getAddressSpace()) 153 return false; 154 155 } else if (FunctionType *FT = dyn_cast<FunctionType>(DstTy)) { 156 if (FT->isVarArg() != cast<FunctionType>(SrcTy)->isVarArg()) 157 return false; 158 } else if (StructType *DSTy = dyn_cast<StructType>(DstTy)) { 159 StructType *SSTy = cast<StructType>(SrcTy); 160 if (DSTy->isLiteral() != SSTy->isLiteral() || 161 DSTy->isPacked() != SSTy->isPacked()) 162 return false; 163 } else if (ArrayType *DATy = dyn_cast<ArrayType>(DstTy)) { 164 if (DATy->getNumElements() != cast<ArrayType>(SrcTy)->getNumElements()) 165 return false; 166 } else if (VectorType *DVTy = dyn_cast<VectorType>(DstTy)) { 167 if (DVTy->getNumElements() != cast<ArrayType>(SrcTy)->getNumElements()) 168 return false; 169 } 170 171 // Otherwise, we speculate that these two types will line up and recursively 172 // check the subelements. 173 Entry = DstTy; 174 SpeculativeTypes.push_back(SrcTy); 175 176 for (unsigned i = 0, e = SrcTy->getNumContainedTypes(); i != e; ++i) 177 if (!areTypesIsomorphic(DstTy->getContainedType(i), 178 SrcTy->getContainedType(i))) 179 return false; 180 181 // If everything seems to have lined up, then everything is great. 182 return true; 183} 184 185/// linkDefinedTypeBodies - Produce a body for an opaque type in the dest 186/// module from a type definition in the source module. 187void TypeMapTy::linkDefinedTypeBodies() { 188 SmallVector<Type*, 16> Elements; 189 SmallString<16> TmpName; 190 191 // Note that processing entries in this loop (calling 'get') can add new 192 // entries to the SrcDefinitionsToResolve vector. 193 while (!SrcDefinitionsToResolve.empty()) { 194 StructType *SrcSTy = SrcDefinitionsToResolve.pop_back_val(); 195 StructType *DstSTy = cast<StructType>(MappedTypes[SrcSTy]); 196 197 // TypeMap is a many-to-one mapping, if there were multiple types that 198 // provide a body for DstSTy then previous iterations of this loop may have 199 // already handled it. Just ignore this case. 200 if (!DstSTy->isOpaque()) continue; 201 assert(!SrcSTy->isOpaque() && "Not resolving a definition?"); 202 203 // Map the body of the source type over to a new body for the dest type. 204 Elements.resize(SrcSTy->getNumElements()); 205 for (unsigned i = 0, e = Elements.size(); i != e; ++i) 206 Elements[i] = getImpl(SrcSTy->getElementType(i)); 207 208 DstSTy->setBody(Elements, SrcSTy->isPacked()); 209 210 // If DstSTy has no name or has a longer name than STy, then viciously steal 211 // STy's name. 212 if (!SrcSTy->hasName()) continue; 213 StringRef SrcName = SrcSTy->getName(); 214 215 if (!DstSTy->hasName() || DstSTy->getName().size() > SrcName.size()) { 216 TmpName.insert(TmpName.end(), SrcName.begin(), SrcName.end()); 217 SrcSTy->setName(""); 218 DstSTy->setName(TmpName.str()); 219 TmpName.clear(); 220 } 221 } 222 223 DstResolvedOpaqueTypes.clear(); 224} 225 226 227/// get - Return the mapped type to use for the specified input type from the 228/// source module. 229Type *TypeMapTy::get(Type *Ty) { 230 Type *Result = getImpl(Ty); 231 232 // If this caused a reference to any struct type, resolve it before returning. 233 if (!SrcDefinitionsToResolve.empty()) 234 linkDefinedTypeBodies(); 235 return Result; 236} 237 238/// getImpl - This is the recursive version of get(). 239Type *TypeMapTy::getImpl(Type *Ty) { 240 // If we already have an entry for this type, return it. 241 Type **Entry = &MappedTypes[Ty]; 242 if (*Entry) return *Entry; 243 244 // If this is not a named struct type, then just map all of the elements and 245 // then rebuild the type from inside out. 246 if (!isa<StructType>(Ty) || cast<StructType>(Ty)->isLiteral()) { 247 // If there are no element types to map, then the type is itself. This is 248 // true for the anonymous {} struct, things like 'float', integers, etc. 249 if (Ty->getNumContainedTypes() == 0) 250 return *Entry = Ty; 251 252 // Remap all of the elements, keeping track of whether any of them change. 253 bool AnyChange = false; 254 SmallVector<Type*, 4> ElementTypes; 255 ElementTypes.resize(Ty->getNumContainedTypes()); 256 for (unsigned i = 0, e = Ty->getNumContainedTypes(); i != e; ++i) { 257 ElementTypes[i] = getImpl(Ty->getContainedType(i)); 258 AnyChange |= ElementTypes[i] != Ty->getContainedType(i); 259 } 260 261 // If we found our type while recursively processing stuff, just use it. 262 Entry = &MappedTypes[Ty]; 263 if (*Entry) return *Entry; 264 265 // If all of the element types mapped directly over, then the type is usable 266 // as-is. 267 if (!AnyChange) 268 return *Entry = Ty; 269 270 // Otherwise, rebuild a modified type. 271 switch (Ty->getTypeID()) { 272 default: llvm_unreachable("unknown derived type to remap"); 273 case Type::ArrayTyID: 274 return *Entry = ArrayType::get(ElementTypes[0], 275 cast<ArrayType>(Ty)->getNumElements()); 276 case Type::VectorTyID: 277 return *Entry = VectorType::get(ElementTypes[0], 278 cast<VectorType>(Ty)->getNumElements()); 279 case Type::PointerTyID: 280 return *Entry = PointerType::get(ElementTypes[0], 281 cast<PointerType>(Ty)->getAddressSpace()); 282 case Type::FunctionTyID: 283 return *Entry = FunctionType::get(ElementTypes[0], 284 makeArrayRef(ElementTypes).slice(1), 285 cast<FunctionType>(Ty)->isVarArg()); 286 case Type::StructTyID: 287 // Note that this is only reached for anonymous structs. 288 return *Entry = StructType::get(Ty->getContext(), ElementTypes, 289 cast<StructType>(Ty)->isPacked()); 290 } 291 } 292 293 // Otherwise, this is an unmapped named struct. If the struct can be directly 294 // mapped over, just use it as-is. This happens in a case when the linked-in 295 // module has something like: 296 // %T = type {%T*, i32} 297 // @GV = global %T* null 298 // where T does not exist at all in the destination module. 299 // 300 // The other case we watch for is when the type is not in the destination 301 // module, but that it has to be rebuilt because it refers to something that 302 // is already mapped. For example, if the destination module has: 303 // %A = type { i32 } 304 // and the source module has something like 305 // %A' = type { i32 } 306 // %B = type { %A'* } 307 // @GV = global %B* null 308 // then we want to create a new type: "%B = type { %A*}" and have it take the 309 // pristine "%B" name from the source module. 310 // 311 // To determine which case this is, we have to recursively walk the type graph 312 // speculating that we'll be able to reuse it unmodified. Only if this is 313 // safe would we map the entire thing over. Because this is an optimization, 314 // and is not required for the prettiness of the linked module, we just skip 315 // it and always rebuild a type here. 316 StructType *STy = cast<StructType>(Ty); 317 318 // If the type is opaque, we can just use it directly. 319 if (STy->isOpaque()) 320 return *Entry = STy; 321 322 // Otherwise we create a new type and resolve its body later. This will be 323 // resolved by the top level of get(). 324 SrcDefinitionsToResolve.push_back(STy); 325 StructType *DTy = StructType::create(STy->getContext()); 326 DstResolvedOpaqueTypes.insert(DTy); 327 return *Entry = DTy; 328} 329 330 331 332//===----------------------------------------------------------------------===// 333// ModuleLinker implementation. 334//===----------------------------------------------------------------------===// 335 336namespace { 337 /// ModuleLinker - This is an implementation class for the LinkModules 338 /// function, which is the entrypoint for this file. 339 class ModuleLinker { 340 Module *DstM, *SrcM; 341 342 TypeMapTy TypeMap; 343 344 /// ValueMap - Mapping of values from what they used to be in Src, to what 345 /// they are now in DstM. ValueToValueMapTy is a ValueMap, which involves 346 /// some overhead due to the use of Value handles which the Linker doesn't 347 /// actually need, but this allows us to reuse the ValueMapper code. 348 ValueToValueMapTy ValueMap; 349 350 struct AppendingVarInfo { 351 GlobalVariable *NewGV; // New aggregate global in dest module. 352 Constant *DstInit; // Old initializer from dest module. 353 Constant *SrcInit; // Old initializer from src module. 354 }; 355 356 std::vector<AppendingVarInfo> AppendingVars; 357 358 unsigned Mode; // Mode to treat source module. 359 360 // Set of items not to link in from source. 361 SmallPtrSet<const Value*, 16> DoNotLinkFromSource; 362 363 // Vector of functions to lazily link in. 364 std::vector<Function*> LazilyLinkFunctions; 365 366 public: 367 std::string ErrorMsg; 368 369 ModuleLinker(Module *dstM, Module *srcM, unsigned mode) 370 : DstM(dstM), SrcM(srcM), Mode(mode) { } 371 372 bool run(); 373 374 private: 375 /// emitError - Helper method for setting a message and returning an error 376 /// code. 377 bool emitError(const Twine &Message) { 378 ErrorMsg = Message.str(); 379 return true; 380 } 381 382 /// getLinkageResult - This analyzes the two global values and determines 383 /// what the result will look like in the destination module. 384 bool getLinkageResult(GlobalValue *Dest, const GlobalValue *Src, 385 GlobalValue::LinkageTypes <, 386 GlobalValue::VisibilityTypes &Vis, 387 bool &LinkFromSrc); 388 389 /// getLinkedToGlobal - Given a global in the source module, return the 390 /// global in the destination module that is being linked to, if any. 391 GlobalValue *getLinkedToGlobal(GlobalValue *SrcGV) { 392 // If the source has no name it can't link. If it has local linkage, 393 // there is no name match-up going on. 394 if (!SrcGV->hasName() || SrcGV->hasLocalLinkage()) 395 return 0; 396 397 // Otherwise see if we have a match in the destination module's symtab. 398 GlobalValue *DGV = DstM->getNamedValue(SrcGV->getName()); 399 if (DGV == 0) return 0; 400 401 // If we found a global with the same name in the dest module, but it has 402 // internal linkage, we are really not doing any linkage here. 403 if (DGV->hasLocalLinkage()) 404 return 0; 405 406 // Otherwise, we do in fact link to the destination global. 407 return DGV; 408 } 409 410 void computeTypeMapping(); 411 bool categorizeModuleFlagNodes(const NamedMDNode *ModFlags, 412 DenseMap<MDString*, MDNode*> &ErrorNode, 413 DenseMap<MDString*, MDNode*> &WarningNode, 414 DenseMap<MDString*, MDNode*> &OverrideNode, 415 DenseMap<MDString*, 416 SmallSetVector<MDNode*, 8> > &RequireNodes, 417 SmallSetVector<MDString*, 16> &SeenIDs); 418 419 bool linkAppendingVarProto(GlobalVariable *DstGV, GlobalVariable *SrcGV); 420 bool linkGlobalProto(GlobalVariable *SrcGV); 421 bool linkFunctionProto(Function *SrcF); 422 bool linkAliasProto(GlobalAlias *SrcA); 423 bool linkModuleFlagsMetadata(); 424 425 void linkAppendingVarInit(const AppendingVarInfo &AVI); 426 void linkGlobalInits(); 427 void linkFunctionBody(Function *Dst, Function *Src); 428 void linkAliasBodies(); 429 void linkNamedMDNodes(); 430 }; 431} 432 433 434 435/// forceRenaming - The LLVM SymbolTable class autorenames globals that conflict 436/// in the symbol table. This is good for all clients except for us. Go 437/// through the trouble to force this back. 438static void forceRenaming(GlobalValue *GV, StringRef Name) { 439 // If the global doesn't force its name or if it already has the right name, 440 // there is nothing for us to do. 441 if (GV->hasLocalLinkage() || GV->getName() == Name) 442 return; 443 444 Module *M = GV->getParent(); 445 446 // If there is a conflict, rename the conflict. 447 if (GlobalValue *ConflictGV = M->getNamedValue(Name)) { 448 GV->takeName(ConflictGV); 449 ConflictGV->setName(Name); // This will cause ConflictGV to get renamed 450 assert(ConflictGV->getName() != Name && "forceRenaming didn't work"); 451 } else { 452 GV->setName(Name); // Force the name back 453 } 454} 455 456/// CopyGVAttributes - copy additional attributes (those not needed to construct 457/// a GlobalValue) from the SrcGV to the DestGV. 458static void CopyGVAttributes(GlobalValue *DestGV, const GlobalValue *SrcGV) { 459 // Use the maximum alignment, rather than just copying the alignment of SrcGV. 460 unsigned Alignment = std::max(DestGV->getAlignment(), SrcGV->getAlignment()); 461 DestGV->copyAttributesFrom(SrcGV); 462 DestGV->setAlignment(Alignment); 463 464 forceRenaming(DestGV, SrcGV->getName()); 465} 466 467static bool isLessConstraining(GlobalValue::VisibilityTypes a, 468 GlobalValue::VisibilityTypes b) { 469 if (a == GlobalValue::HiddenVisibility) 470 return false; 471 if (b == GlobalValue::HiddenVisibility) 472 return true; 473 if (a == GlobalValue::ProtectedVisibility) 474 return false; 475 if (b == GlobalValue::ProtectedVisibility) 476 return true; 477 return false; 478} 479 480/// getLinkageResult - This analyzes the two global values and determines what 481/// the result will look like in the destination module. In particular, it 482/// computes the resultant linkage type and visibility, computes whether the 483/// global in the source should be copied over to the destination (replacing 484/// the existing one), and computes whether this linkage is an error or not. 485bool ModuleLinker::getLinkageResult(GlobalValue *Dest, const GlobalValue *Src, 486 GlobalValue::LinkageTypes <, 487 GlobalValue::VisibilityTypes &Vis, 488 bool &LinkFromSrc) { 489 assert(Dest && "Must have two globals being queried"); 490 assert(!Src->hasLocalLinkage() && 491 "If Src has internal linkage, Dest shouldn't be set!"); 492 493 bool SrcIsDeclaration = Src->isDeclaration() && !Src->isMaterializable(); 494 bool DestIsDeclaration = Dest->isDeclaration(); 495 496 if (SrcIsDeclaration) { 497 // If Src is external or if both Src & Dest are external.. Just link the 498 // external globals, we aren't adding anything. 499 if (Src->hasDLLImportLinkage()) { 500 // If one of GVs has DLLImport linkage, result should be dllimport'ed. 501 if (DestIsDeclaration) { 502 LinkFromSrc = true; 503 LT = Src->getLinkage(); 504 } 505 } else if (Dest->hasExternalWeakLinkage()) { 506 // If the Dest is weak, use the source linkage. 507 LinkFromSrc = true; 508 LT = Src->getLinkage(); 509 } else { 510 LinkFromSrc = false; 511 LT = Dest->getLinkage(); 512 } 513 } else if (DestIsDeclaration && !Dest->hasDLLImportLinkage()) { 514 // If Dest is external but Src is not: 515 LinkFromSrc = true; 516 LT = Src->getLinkage(); 517 } else if (Src->isWeakForLinker()) { 518 // At this point we know that Dest has LinkOnce, External*, Weak, Common, 519 // or DLL* linkage. 520 if (Dest->hasExternalWeakLinkage() || 521 Dest->hasAvailableExternallyLinkage() || 522 (Dest->hasLinkOnceLinkage() && 523 (Src->hasWeakLinkage() || Src->hasCommonLinkage()))) { 524 LinkFromSrc = true; 525 LT = Src->getLinkage(); 526 } else { 527 LinkFromSrc = false; 528 LT = Dest->getLinkage(); 529 } 530 } else if (Dest->isWeakForLinker()) { 531 // At this point we know that Src has External* or DLL* linkage. 532 if (Src->hasExternalWeakLinkage()) { 533 LinkFromSrc = false; 534 LT = Dest->getLinkage(); 535 } else { 536 LinkFromSrc = true; 537 LT = GlobalValue::ExternalLinkage; 538 } 539 } else { 540 assert((Dest->hasExternalLinkage() || Dest->hasDLLImportLinkage() || 541 Dest->hasDLLExportLinkage() || Dest->hasExternalWeakLinkage()) && 542 (Src->hasExternalLinkage() || Src->hasDLLImportLinkage() || 543 Src->hasDLLExportLinkage() || Src->hasExternalWeakLinkage()) && 544 "Unexpected linkage type!"); 545 return emitError("Linking globals named '" + Src->getName() + 546 "': symbol multiply defined!"); 547 } 548 549 // Compute the visibility. We follow the rules in the System V Application 550 // Binary Interface. 551 Vis = isLessConstraining(Src->getVisibility(), Dest->getVisibility()) ? 552 Dest->getVisibility() : Src->getVisibility(); 553 return false; 554} 555 556/// computeTypeMapping - Loop over all of the linked values to compute type 557/// mappings. For example, if we link "extern Foo *x" and "Foo *x = NULL", then 558/// we have two struct types 'Foo' but one got renamed when the module was 559/// loaded into the same LLVMContext. 560void ModuleLinker::computeTypeMapping() { 561 // Incorporate globals. 562 for (Module::global_iterator I = SrcM->global_begin(), 563 E = SrcM->global_end(); I != E; ++I) { 564 GlobalValue *DGV = getLinkedToGlobal(I); 565 if (DGV == 0) continue; 566 567 if (!DGV->hasAppendingLinkage() || !I->hasAppendingLinkage()) { 568 TypeMap.addTypeMapping(DGV->getType(), I->getType()); 569 continue; 570 } 571 572 // Unify the element type of appending arrays. 573 ArrayType *DAT = cast<ArrayType>(DGV->getType()->getElementType()); 574 ArrayType *SAT = cast<ArrayType>(I->getType()->getElementType()); 575 TypeMap.addTypeMapping(DAT->getElementType(), SAT->getElementType()); 576 } 577 578 // Incorporate functions. 579 for (Module::iterator I = SrcM->begin(), E = SrcM->end(); I != E; ++I) { 580 if (GlobalValue *DGV = getLinkedToGlobal(I)) 581 TypeMap.addTypeMapping(DGV->getType(), I->getType()); 582 } 583 584#if 0 585 // FIXME: This doesn't play well with LTO. We cannot compile LLVM with this 586 // enabled. <rdar://problem/10913281>. 587 588 // Incorporate types by name, scanning all the types in the source module. 589 // At this point, the destination module may have a type "%foo = { i32 }" for 590 // example. When the source module got loaded into the same LLVMContext, if 591 // it had the same type, it would have been renamed to "%foo.42 = { i32 }". 592 // Though it isn't required for correctness, attempt to link these up to clean 593 // up the IR. 594 std::vector<StructType*> SrcStructTypes; 595 SrcM->findUsedStructTypes(SrcStructTypes); 596 597 SmallPtrSet<StructType*, 32> SrcStructTypesSet(SrcStructTypes.begin(), 598 SrcStructTypes.end()); 599 600 for (unsigned i = 0, e = SrcStructTypes.size(); i != e; ++i) { 601 StructType *ST = SrcStructTypes[i]; 602 if (!ST->hasName()) continue; 603 604 // Check to see if there is a dot in the name followed by a digit. 605 size_t DotPos = ST->getName().rfind('.'); 606 if (DotPos == 0 || DotPos == StringRef::npos || 607 ST->getName().back() == '.' || !isdigit(ST->getName()[DotPos+1])) 608 continue; 609 610 // Check to see if the destination module has a struct with the prefix name. 611 if (StructType *DST = DstM->getTypeByName(ST->getName().substr(0, DotPos))) 612 // Don't use it if this actually came from the source module. They're in 613 // the same LLVMContext after all. 614 if (!SrcStructTypesSet.count(DST)) 615 TypeMap.addTypeMapping(DST, ST); 616 } 617#endif 618 619 // Don't bother incorporating aliases, they aren't generally typed well. 620 621 // Now that we have discovered all of the type equivalences, get a body for 622 // any 'opaque' types in the dest module that are now resolved. 623 TypeMap.linkDefinedTypeBodies(); 624} 625 626/// linkAppendingVarProto - If there were any appending global variables, link 627/// them together now. Return true on error. 628bool ModuleLinker::linkAppendingVarProto(GlobalVariable *DstGV, 629 GlobalVariable *SrcGV) { 630 631 if (!SrcGV->hasAppendingLinkage() || !DstGV->hasAppendingLinkage()) 632 return emitError("Linking globals named '" + SrcGV->getName() + 633 "': can only link appending global with another appending global!"); 634 635 ArrayType *DstTy = cast<ArrayType>(DstGV->getType()->getElementType()); 636 ArrayType *SrcTy = 637 cast<ArrayType>(TypeMap.get(SrcGV->getType()->getElementType())); 638 Type *EltTy = DstTy->getElementType(); 639 640 // Check to see that they two arrays agree on type. 641 if (EltTy != SrcTy->getElementType()) 642 return emitError("Appending variables with different element types!"); 643 if (DstGV->isConstant() != SrcGV->isConstant()) 644 return emitError("Appending variables linked with different const'ness!"); 645 646 if (DstGV->getAlignment() != SrcGV->getAlignment()) 647 return emitError( 648 "Appending variables with different alignment need to be linked!"); 649 650 if (DstGV->getVisibility() != SrcGV->getVisibility()) 651 return emitError( 652 "Appending variables with different visibility need to be linked!"); 653 654 if (DstGV->getSection() != SrcGV->getSection()) 655 return emitError( 656 "Appending variables with different section name need to be linked!"); 657 658 uint64_t NewSize = DstTy->getNumElements() + SrcTy->getNumElements(); 659 ArrayType *NewType = ArrayType::get(EltTy, NewSize); 660 661 // Create the new global variable. 662 GlobalVariable *NG = 663 new GlobalVariable(*DstGV->getParent(), NewType, SrcGV->isConstant(), 664 DstGV->getLinkage(), /*init*/0, /*name*/"", DstGV, 665 DstGV->isThreadLocal(), 666 DstGV->getType()->getAddressSpace()); 667 668 // Propagate alignment, visibility and section info. 669 CopyGVAttributes(NG, DstGV); 670 671 AppendingVarInfo AVI; 672 AVI.NewGV = NG; 673 AVI.DstInit = DstGV->getInitializer(); 674 AVI.SrcInit = SrcGV->getInitializer(); 675 AppendingVars.push_back(AVI); 676 677 // Replace any uses of the two global variables with uses of the new 678 // global. 679 ValueMap[SrcGV] = ConstantExpr::getBitCast(NG, TypeMap.get(SrcGV->getType())); 680 681 DstGV->replaceAllUsesWith(ConstantExpr::getBitCast(NG, DstGV->getType())); 682 DstGV->eraseFromParent(); 683 684 // Track the source variable so we don't try to link it. 685 DoNotLinkFromSource.insert(SrcGV); 686 687 return false; 688} 689 690/// linkGlobalProto - Loop through the global variables in the src module and 691/// merge them into the dest module. 692bool ModuleLinker::linkGlobalProto(GlobalVariable *SGV) { 693 GlobalValue *DGV = getLinkedToGlobal(SGV); 694 llvm::Optional<GlobalValue::VisibilityTypes> NewVisibility; 695 696 if (DGV) { 697 // Concatenation of appending linkage variables is magic and handled later. 698 if (DGV->hasAppendingLinkage() || SGV->hasAppendingLinkage()) 699 return linkAppendingVarProto(cast<GlobalVariable>(DGV), SGV); 700 701 // Determine whether linkage of these two globals follows the source 702 // module's definition or the destination module's definition. 703 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; 704 GlobalValue::VisibilityTypes NV; 705 bool LinkFromSrc = false; 706 if (getLinkageResult(DGV, SGV, NewLinkage, NV, LinkFromSrc)) 707 return true; 708 NewVisibility = NV; 709 710 // If we're not linking from the source, then keep the definition that we 711 // have. 712 if (!LinkFromSrc) { 713 // Special case for const propagation. 714 if (GlobalVariable *DGVar = dyn_cast<GlobalVariable>(DGV)) 715 if (DGVar->isDeclaration() && SGV->isConstant() && !DGVar->isConstant()) 716 DGVar->setConstant(true); 717 718 // Set calculated linkage and visibility. 719 DGV->setLinkage(NewLinkage); 720 DGV->setVisibility(*NewVisibility); 721 722 // Make sure to remember this mapping. 723 ValueMap[SGV] = ConstantExpr::getBitCast(DGV,TypeMap.get(SGV->getType())); 724 725 // Track the source global so that we don't attempt to copy it over when 726 // processing global initializers. 727 DoNotLinkFromSource.insert(SGV); 728 729 return false; 730 } 731 } 732 733 // No linking to be performed or linking from the source: simply create an 734 // identical version of the symbol over in the dest module... the 735 // initializer will be filled in later by LinkGlobalInits. 736 GlobalVariable *NewDGV = 737 new GlobalVariable(*DstM, TypeMap.get(SGV->getType()->getElementType()), 738 SGV->isConstant(), SGV->getLinkage(), /*init*/0, 739 SGV->getName(), /*insertbefore*/0, 740 SGV->isThreadLocal(), 741 SGV->getType()->getAddressSpace()); 742 // Propagate alignment, visibility and section info. 743 CopyGVAttributes(NewDGV, SGV); 744 if (NewVisibility) 745 NewDGV->setVisibility(*NewVisibility); 746 747 if (DGV) { 748 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDGV, DGV->getType())); 749 DGV->eraseFromParent(); 750 } 751 752 // Make sure to remember this mapping. 753 ValueMap[SGV] = NewDGV; 754 return false; 755} 756 757/// linkFunctionProto - Link the function in the source module into the 758/// destination module if needed, setting up mapping information. 759bool ModuleLinker::linkFunctionProto(Function *SF) { 760 GlobalValue *DGV = getLinkedToGlobal(SF); 761 llvm::Optional<GlobalValue::VisibilityTypes> NewVisibility; 762 763 if (DGV) { 764 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; 765 bool LinkFromSrc = false; 766 GlobalValue::VisibilityTypes NV; 767 if (getLinkageResult(DGV, SF, NewLinkage, NV, LinkFromSrc)) 768 return true; 769 NewVisibility = NV; 770 771 if (!LinkFromSrc) { 772 // Set calculated linkage 773 DGV->setLinkage(NewLinkage); 774 DGV->setVisibility(*NewVisibility); 775 776 // Make sure to remember this mapping. 777 ValueMap[SF] = ConstantExpr::getBitCast(DGV, TypeMap.get(SF->getType())); 778 779 // Track the function from the source module so we don't attempt to remap 780 // it. 781 DoNotLinkFromSource.insert(SF); 782 783 return false; 784 } 785 } 786 787 // If there is no linkage to be performed or we are linking from the source, 788 // bring SF over. 789 Function *NewDF = Function::Create(TypeMap.get(SF->getFunctionType()), 790 SF->getLinkage(), SF->getName(), DstM); 791 CopyGVAttributes(NewDF, SF); 792 if (NewVisibility) 793 NewDF->setVisibility(*NewVisibility); 794 795 if (DGV) { 796 // Any uses of DF need to change to NewDF, with cast. 797 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDF, DGV->getType())); 798 DGV->eraseFromParent(); 799 } else { 800 // Internal, LO_ODR, or LO linkage - stick in set to ignore and lazily link. 801 if (SF->hasLocalLinkage() || SF->hasLinkOnceLinkage() || 802 SF->hasAvailableExternallyLinkage()) { 803 DoNotLinkFromSource.insert(SF); 804 LazilyLinkFunctions.push_back(SF); 805 } 806 } 807 808 ValueMap[SF] = NewDF; 809 return false; 810} 811 812/// LinkAliasProto - Set up prototypes for any aliases that come over from the 813/// source module. 814bool ModuleLinker::linkAliasProto(GlobalAlias *SGA) { 815 GlobalValue *DGV = getLinkedToGlobal(SGA); 816 llvm::Optional<GlobalValue::VisibilityTypes> NewVisibility; 817 818 if (DGV) { 819 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; 820 GlobalValue::VisibilityTypes NV; 821 bool LinkFromSrc = false; 822 if (getLinkageResult(DGV, SGA, NewLinkage, NV, LinkFromSrc)) 823 return true; 824 NewVisibility = NV; 825 826 if (!LinkFromSrc) { 827 // Set calculated linkage. 828 DGV->setLinkage(NewLinkage); 829 DGV->setVisibility(*NewVisibility); 830 831 // Make sure to remember this mapping. 832 ValueMap[SGA] = ConstantExpr::getBitCast(DGV,TypeMap.get(SGA->getType())); 833 834 // Track the alias from the source module so we don't attempt to remap it. 835 DoNotLinkFromSource.insert(SGA); 836 837 return false; 838 } 839 } 840 841 // If there is no linkage to be performed or we're linking from the source, 842 // bring over SGA. 843 GlobalAlias *NewDA = new GlobalAlias(TypeMap.get(SGA->getType()), 844 SGA->getLinkage(), SGA->getName(), 845 /*aliasee*/0, DstM); 846 CopyGVAttributes(NewDA, SGA); 847 if (NewVisibility) 848 NewDA->setVisibility(*NewVisibility); 849 850 if (DGV) { 851 // Any uses of DGV need to change to NewDA, with cast. 852 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDA, DGV->getType())); 853 DGV->eraseFromParent(); 854 } 855 856 ValueMap[SGA] = NewDA; 857 return false; 858} 859 860static void getArrayElements(Constant *C, SmallVectorImpl<Constant*> &Dest) { 861 unsigned NumElements = cast<ArrayType>(C->getType())->getNumElements(); 862 863 for (unsigned i = 0; i != NumElements; ++i) 864 Dest.push_back(C->getAggregateElement(i)); 865} 866 867void ModuleLinker::linkAppendingVarInit(const AppendingVarInfo &AVI) { 868 // Merge the initializer. 869 SmallVector<Constant*, 16> Elements; 870 getArrayElements(AVI.DstInit, Elements); 871 872 Constant *SrcInit = MapValue(AVI.SrcInit, ValueMap, RF_None, &TypeMap); 873 getArrayElements(SrcInit, Elements); 874 875 ArrayType *NewType = cast<ArrayType>(AVI.NewGV->getType()->getElementType()); 876 AVI.NewGV->setInitializer(ConstantArray::get(NewType, Elements)); 877} 878 879 880// linkGlobalInits - Update the initializers in the Dest module now that all 881// globals that may be referenced are in Dest. 882void ModuleLinker::linkGlobalInits() { 883 // Loop over all of the globals in the src module, mapping them over as we go 884 for (Module::const_global_iterator I = SrcM->global_begin(), 885 E = SrcM->global_end(); I != E; ++I) { 886 887 // Only process initialized GV's or ones not already in dest. 888 if (!I->hasInitializer() || DoNotLinkFromSource.count(I)) continue; 889 890 // Grab destination global variable. 891 GlobalVariable *DGV = cast<GlobalVariable>(ValueMap[I]); 892 // Figure out what the initializer looks like in the dest module. 893 DGV->setInitializer(MapValue(I->getInitializer(), ValueMap, 894 RF_None, &TypeMap)); 895 } 896} 897 898// linkFunctionBody - Copy the source function over into the dest function and 899// fix up references to values. At this point we know that Dest is an external 900// function, and that Src is not. 901void ModuleLinker::linkFunctionBody(Function *Dst, Function *Src) { 902 assert(Src && Dst && Dst->isDeclaration() && !Src->isDeclaration()); 903 904 // Go through and convert function arguments over, remembering the mapping. 905 Function::arg_iterator DI = Dst->arg_begin(); 906 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end(); 907 I != E; ++I, ++DI) { 908 DI->setName(I->getName()); // Copy the name over. 909 910 // Add a mapping to our mapping. 911 ValueMap[I] = DI; 912 } 913 914 if (Mode == Linker::DestroySource) { 915 // Splice the body of the source function into the dest function. 916 Dst->getBasicBlockList().splice(Dst->end(), Src->getBasicBlockList()); 917 918 // At this point, all of the instructions and values of the function are now 919 // copied over. The only problem is that they are still referencing values in 920 // the Source function as operands. Loop through all of the operands of the 921 // functions and patch them up to point to the local versions. 922 for (Function::iterator BB = Dst->begin(), BE = Dst->end(); BB != BE; ++BB) 923 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) 924 RemapInstruction(I, ValueMap, RF_IgnoreMissingEntries, &TypeMap); 925 926 } else { 927 // Clone the body of the function into the dest function. 928 SmallVector<ReturnInst*, 8> Returns; // Ignore returns. 929 CloneFunctionInto(Dst, Src, ValueMap, false, Returns, "", NULL, &TypeMap); 930 } 931 932 // There is no need to map the arguments anymore. 933 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end(); 934 I != E; ++I) 935 ValueMap.erase(I); 936 937} 938 939 940void ModuleLinker::linkAliasBodies() { 941 for (Module::alias_iterator I = SrcM->alias_begin(), E = SrcM->alias_end(); 942 I != E; ++I) { 943 if (DoNotLinkFromSource.count(I)) 944 continue; 945 if (Constant *Aliasee = I->getAliasee()) { 946 GlobalAlias *DA = cast<GlobalAlias>(ValueMap[I]); 947 DA->setAliasee(MapValue(Aliasee, ValueMap, RF_None, &TypeMap)); 948 } 949 } 950} 951 952/// linkNamedMDNodes - Insert all of the named mdnodes in Src into the Dest 953/// module. 954void ModuleLinker::linkNamedMDNodes() { 955 const NamedMDNode *SrcModFlags = SrcM->getModuleFlagsMetadata(); 956 for (Module::const_named_metadata_iterator I = SrcM->named_metadata_begin(), 957 E = SrcM->named_metadata_end(); I != E; ++I) { 958 // Don't link module flags here. Do them separately. 959 if (&*I == SrcModFlags) continue; 960 NamedMDNode *DestNMD = DstM->getOrInsertNamedMetadata(I->getName()); 961 // Add Src elements into Dest node. 962 for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) 963 DestNMD->addOperand(MapValue(I->getOperand(i), ValueMap, 964 RF_None, &TypeMap)); 965 } 966} 967 968/// categorizeModuleFlagNodes - 969bool ModuleLinker:: 970categorizeModuleFlagNodes(const NamedMDNode *ModFlags, 971 DenseMap<MDString*, MDNode*> &ErrorNode, 972 DenseMap<MDString*, MDNode*> &WarningNode, 973 DenseMap<MDString*, MDNode*> &OverrideNode, 974 DenseMap<MDString*, 975 SmallSetVector<MDNode*, 8> > &RequireNodes, 976 SmallSetVector<MDString*, 16> &SeenIDs) { 977 bool HasErr = false; 978 979 for (unsigned I = 0, E = ModFlags->getNumOperands(); I != E; ++I) { 980 MDNode *Op = ModFlags->getOperand(I); 981 assert(Op->getNumOperands() == 3 && "Invalid module flag metadata!"); 982 assert(isa<ConstantInt>(Op->getOperand(0)) && 983 "Module flag's first operand must be an integer!"); 984 assert(isa<MDString>(Op->getOperand(1)) && 985 "Module flag's second operand must be an MDString!"); 986 987 ConstantInt *Behavior = cast<ConstantInt>(Op->getOperand(0)); 988 MDString *ID = cast<MDString>(Op->getOperand(1)); 989 Value *Val = Op->getOperand(2); 990 switch (Behavior->getZExtValue()) { 991 default: 992 assert(false && "Invalid behavior in module flag metadata!"); 993 break; 994 case Module::Error: { 995 MDNode *&ErrNode = ErrorNode[ID]; 996 if (!ErrNode) ErrNode = Op; 997 if (ErrNode->getOperand(2) != Val) 998 HasErr = emitError("linking module flags '" + ID->getString() + 999 "': IDs have conflicting values"); 1000 break; 1001 } 1002 case Module::Warning: { 1003 MDNode *&WarnNode = WarningNode[ID]; 1004 if (!WarnNode) WarnNode = Op; 1005 if (WarnNode->getOperand(2) != Val) 1006 errs() << "WARNING: linking module flags '" << ID->getString() 1007 << "': IDs have conflicting values"; 1008 break; 1009 } 1010 case Module::Require: RequireNodes[ID].insert(Op); break; 1011 case Module::Override: { 1012 MDNode *&OvrNode = OverrideNode[ID]; 1013 if (!OvrNode) OvrNode = Op; 1014 if (OvrNode->getOperand(2) != Val) 1015 HasErr = emitError("linking module flags '" + ID->getString() + 1016 "': IDs have conflicting override values"); 1017 break; 1018 } 1019 } 1020 1021 SeenIDs.insert(ID); 1022 } 1023 1024 return HasErr; 1025} 1026 1027/// linkModuleFlagsMetadata - Merge the linker flags in Src into the Dest 1028/// module. 1029bool ModuleLinker::linkModuleFlagsMetadata() { 1030 const NamedMDNode *SrcModFlags = SrcM->getModuleFlagsMetadata(); 1031 if (!SrcModFlags) return false; 1032 1033 NamedMDNode *DstModFlags = DstM->getOrInsertModuleFlagsMetadata(); 1034 1035 // If the destination module doesn't have module flags yet, then just copy 1036 // over the source module's flags. 1037 if (DstModFlags->getNumOperands() == 0) { 1038 for (unsigned I = 0, E = SrcModFlags->getNumOperands(); I != E; ++I) 1039 DstModFlags->addOperand(SrcModFlags->getOperand(I)); 1040 1041 return false; 1042 } 1043 1044 bool HasErr = false; 1045 1046 // Otherwise, we have to merge them based on their behaviors. First, 1047 // categorize all of the nodes in the modules' module flags. If an error or 1048 // warning occurs, then emit the appropriate message(s). 1049 DenseMap<MDString*, MDNode*> ErrorNode; 1050 DenseMap<MDString*, MDNode*> WarningNode; 1051 DenseMap<MDString*, MDNode*> OverrideNode; 1052 DenseMap<MDString*, SmallSetVector<MDNode*, 8> > RequireNodes; 1053 SmallSetVector<MDString*, 16> SeenIDs; 1054 1055 HasErr |= categorizeModuleFlagNodes(SrcModFlags, ErrorNode, WarningNode, 1056 OverrideNode, RequireNodes, SeenIDs); 1057 HasErr |= categorizeModuleFlagNodes(DstModFlags, ErrorNode, WarningNode, 1058 OverrideNode, RequireNodes, SeenIDs); 1059 1060 // Check that there isn't both an error and warning node for a flag. 1061 for (SmallSetVector<MDString*, 16>::iterator 1062 I = SeenIDs.begin(), E = SeenIDs.end(); I != E; ++I) { 1063 MDString *ID = *I; 1064 if (ErrorNode[ID] && WarningNode[ID]) 1065 HasErr = emitError("linking module flags '" + ID->getString() + 1066 "': IDs have conflicting behaviors"); 1067 } 1068 1069 // Early exit if we had an error. 1070 if (HasErr) return true; 1071 1072 // Get the destination's module flags ready for new operands. 1073 DstModFlags->dropAllReferences(); 1074 1075 // Add all of the module flags to the destination module. 1076 DenseMap<MDString*, SmallVector<MDNode*, 4> > AddedNodes; 1077 for (SmallSetVector<MDString*, 16>::iterator 1078 I = SeenIDs.begin(), E = SeenIDs.end(); I != E; ++I) { 1079 MDString *ID = *I; 1080 if (OverrideNode[ID]) { 1081 DstModFlags->addOperand(OverrideNode[ID]); 1082 AddedNodes[ID].push_back(OverrideNode[ID]); 1083 } else if (ErrorNode[ID]) { 1084 DstModFlags->addOperand(ErrorNode[ID]); 1085 AddedNodes[ID].push_back(ErrorNode[ID]); 1086 } else if (WarningNode[ID]) { 1087 DstModFlags->addOperand(WarningNode[ID]); 1088 AddedNodes[ID].push_back(WarningNode[ID]); 1089 } 1090 1091 for (SmallSetVector<MDNode*, 8>::iterator 1092 II = RequireNodes[ID].begin(), IE = RequireNodes[ID].end(); 1093 II != IE; ++II) 1094 DstModFlags->addOperand(*II); 1095 } 1096 1097 // Now check that all of the requirements have been satisfied. 1098 for (SmallSetVector<MDString*, 16>::iterator 1099 I = SeenIDs.begin(), E = SeenIDs.end(); I != E; ++I) { 1100 MDString *ID = *I; 1101 SmallSetVector<MDNode*, 8> &Set = RequireNodes[ID]; 1102 1103 for (SmallSetVector<MDNode*, 8>::iterator 1104 II = Set.begin(), IE = Set.end(); II != IE; ++II) { 1105 MDNode *Node = *II; 1106 assert(isa<MDNode>(Node->getOperand(2)) && 1107 "Module flag's third operand must be an MDNode!"); 1108 MDNode *Val = cast<MDNode>(Node->getOperand(2)); 1109 1110 MDString *ReqID = cast<MDString>(Val->getOperand(0)); 1111 Value *ReqVal = Val->getOperand(1); 1112 1113 bool HasValue = false; 1114 for (SmallVectorImpl<MDNode*>::iterator 1115 RI = AddedNodes[ReqID].begin(), RE = AddedNodes[ReqID].end(); 1116 RI != RE; ++RI) { 1117 MDNode *ReqNode = *RI; 1118 if (ReqNode->getOperand(2) == ReqVal) { 1119 HasValue = true; 1120 break; 1121 } 1122 } 1123 1124 if (!HasValue) 1125 HasErr = emitError("linking module flags '" + ReqID->getString() + 1126 "': does not have the required value"); 1127 } 1128 } 1129 1130 return HasErr; 1131} 1132 1133bool ModuleLinker::run() { 1134 assert(DstM && "Null destination module"); 1135 assert(SrcM && "Null source module"); 1136 1137 // Inherit the target data from the source module if the destination module 1138 // doesn't have one already. 1139 if (DstM->getDataLayout().empty() && !SrcM->getDataLayout().empty()) 1140 DstM->setDataLayout(SrcM->getDataLayout()); 1141 1142 // Copy the target triple from the source to dest if the dest's is empty. 1143 if (DstM->getTargetTriple().empty() && !SrcM->getTargetTriple().empty()) 1144 DstM->setTargetTriple(SrcM->getTargetTriple()); 1145 1146 if (!SrcM->getDataLayout().empty() && !DstM->getDataLayout().empty() && 1147 SrcM->getDataLayout() != DstM->getDataLayout()) 1148 errs() << "WARNING: Linking two modules of different data layouts!\n"; 1149 if (!SrcM->getTargetTriple().empty() && 1150 DstM->getTargetTriple() != SrcM->getTargetTriple()) { 1151 errs() << "WARNING: Linking two modules of different target triples: "; 1152 if (!SrcM->getModuleIdentifier().empty()) 1153 errs() << SrcM->getModuleIdentifier() << ": "; 1154 errs() << "'" << SrcM->getTargetTriple() << "' and '" 1155 << DstM->getTargetTriple() << "'\n"; 1156 } 1157 1158 // Append the module inline asm string. 1159 if (!SrcM->getModuleInlineAsm().empty()) { 1160 if (DstM->getModuleInlineAsm().empty()) 1161 DstM->setModuleInlineAsm(SrcM->getModuleInlineAsm()); 1162 else 1163 DstM->setModuleInlineAsm(DstM->getModuleInlineAsm()+"\n"+ 1164 SrcM->getModuleInlineAsm()); 1165 } 1166 1167 // Update the destination module's dependent libraries list with the libraries 1168 // from the source module. There's no opportunity for duplicates here as the 1169 // Module ensures that duplicate insertions are discarded. 1170 for (Module::lib_iterator SI = SrcM->lib_begin(), SE = SrcM->lib_end(); 1171 SI != SE; ++SI) 1172 DstM->addLibrary(*SI); 1173 1174 // If the source library's module id is in the dependent library list of the 1175 // destination library, remove it since that module is now linked in. 1176 StringRef ModuleId = SrcM->getModuleIdentifier(); 1177 if (!ModuleId.empty()) 1178 DstM->removeLibrary(sys::path::stem(ModuleId)); 1179 1180 // Loop over all of the linked values to compute type mappings. 1181 computeTypeMapping(); 1182 1183 // Insert all of the globals in src into the DstM module... without linking 1184 // initializers (which could refer to functions not yet mapped over). 1185 for (Module::global_iterator I = SrcM->global_begin(), 1186 E = SrcM->global_end(); I != E; ++I) 1187 if (linkGlobalProto(I)) 1188 return true; 1189 1190 // Link the functions together between the two modules, without doing function 1191 // bodies... this just adds external function prototypes to the DstM 1192 // function... We do this so that when we begin processing function bodies, 1193 // all of the global values that may be referenced are available in our 1194 // ValueMap. 1195 for (Module::iterator I = SrcM->begin(), E = SrcM->end(); I != E; ++I) 1196 if (linkFunctionProto(I)) 1197 return true; 1198 1199 // If there were any aliases, link them now. 1200 for (Module::alias_iterator I = SrcM->alias_begin(), 1201 E = SrcM->alias_end(); I != E; ++I) 1202 if (linkAliasProto(I)) 1203 return true; 1204 1205 for (unsigned i = 0, e = AppendingVars.size(); i != e; ++i) 1206 linkAppendingVarInit(AppendingVars[i]); 1207 1208 // Update the initializers in the DstM module now that all globals that may 1209 // be referenced are in DstM. 1210 linkGlobalInits(); 1211 1212 // Link in the function bodies that are defined in the source module into 1213 // DstM. 1214 for (Module::iterator SF = SrcM->begin(), E = SrcM->end(); SF != E; ++SF) { 1215 // Skip if not linking from source. 1216 if (DoNotLinkFromSource.count(SF)) continue; 1217 1218 // Skip if no body (function is external) or materialize. 1219 if (SF->isDeclaration()) { 1220 if (!SF->isMaterializable()) 1221 continue; 1222 if (SF->Materialize(&ErrorMsg)) 1223 return true; 1224 } 1225 1226 linkFunctionBody(cast<Function>(ValueMap[SF]), SF); 1227 } 1228 1229 // Resolve all uses of aliases with aliasees. 1230 linkAliasBodies(); 1231 1232 // Remap all of the named MDNodes in Src into the DstM module. We do this 1233 // after linking GlobalValues so that MDNodes that reference GlobalValues 1234 // are properly remapped. 1235 linkNamedMDNodes(); 1236 1237 // Merge the module flags into the DstM module. 1238 if (linkModuleFlagsMetadata()) 1239 return true; 1240 1241 // Process vector of lazily linked in functions. 1242 bool LinkedInAnyFunctions; 1243 do { 1244 LinkedInAnyFunctions = false; 1245 1246 for(std::vector<Function*>::iterator I = LazilyLinkFunctions.begin(), 1247 E = LazilyLinkFunctions.end(); I != E; ++I) { 1248 if (!*I) 1249 continue; 1250 1251 Function *SF = *I; 1252 Function *DF = cast<Function>(ValueMap[SF]); 1253 1254 if (!DF->use_empty()) { 1255 1256 // Materialize if necessary. 1257 if (SF->isDeclaration()) { 1258 if (!SF->isMaterializable()) 1259 continue; 1260 if (SF->Materialize(&ErrorMsg)) 1261 return true; 1262 } 1263 1264 // Link in function body. 1265 linkFunctionBody(DF, SF); 1266 1267 // "Remove" from vector by setting the element to 0. 1268 *I = 0; 1269 1270 // Set flag to indicate we may have more functions to lazily link in 1271 // since we linked in a function. 1272 LinkedInAnyFunctions = true; 1273 } 1274 } 1275 } while (LinkedInAnyFunctions); 1276 1277 // Remove any prototypes of functions that were not actually linked in. 1278 for(std::vector<Function*>::iterator I = LazilyLinkFunctions.begin(), 1279 E = LazilyLinkFunctions.end(); I != E; ++I) { 1280 if (!*I) 1281 continue; 1282 1283 Function *SF = *I; 1284 Function *DF = cast<Function>(ValueMap[SF]); 1285 if (DF->use_empty()) 1286 DF->eraseFromParent(); 1287 } 1288 1289 // Now that all of the types from the source are used, resolve any structs 1290 // copied over to the dest that didn't exist there. 1291 TypeMap.linkDefinedTypeBodies(); 1292 1293 return false; 1294} 1295 1296//===----------------------------------------------------------------------===// 1297// LinkModules entrypoint. 1298//===----------------------------------------------------------------------===// 1299 1300// LinkModules - This function links two modules together, with the resulting 1301// left module modified to be the composite of the two input modules. If an 1302// error occurs, true is returned and ErrorMsg (if not null) is set to indicate 1303// the problem. Upon failure, the Dest module could be in a modified state, and 1304// shouldn't be relied on to be consistent. 1305bool Linker::LinkModules(Module *Dest, Module *Src, unsigned Mode, 1306 std::string *ErrorMsg) { 1307 ModuleLinker TheLinker(Dest, Src, Mode); 1308 if (TheLinker.run()) { 1309 if (ErrorMsg) *ErrorMsg = TheLinker.ErrorMsg; 1310 return true; 1311 } 1312 1313 return false; 1314} 1315