LinkModules.cpp revision f24fde20c8d6db5a52b50a010e831c9159d3fec7
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 "llvm-c/Linker.h" 29#include <cctype> 30using namespace llvm; 31 32//===----------------------------------------------------------------------===// 33// TypeMap implementation. 34//===----------------------------------------------------------------------===// 35 36namespace { 37class TypeMapTy : public ValueMapTypeRemapper { 38 /// MappedTypes - This is a mapping from a source type to a destination type 39 /// to use. 40 DenseMap<Type*, Type*> MappedTypes; 41 42 /// SpeculativeTypes - When checking to see if two subgraphs are isomorphic, 43 /// we speculatively add types to MappedTypes, but keep track of them here in 44 /// case we need to roll back. 45 SmallVector<Type*, 16> SpeculativeTypes; 46 47 /// SrcDefinitionsToResolve - This is a list of non-opaque structs in the 48 /// source module that are mapped to an opaque struct in the destination 49 /// module. 50 SmallVector<StructType*, 16> SrcDefinitionsToResolve; 51 52 /// DstResolvedOpaqueTypes - This is the set of opaque types in the 53 /// destination modules who are getting a body from the source module. 54 SmallPtrSet<StructType*, 16> DstResolvedOpaqueTypes; 55 56public: 57 /// addTypeMapping - Indicate that the specified type in the destination 58 /// module is conceptually equivalent to the specified type in the source 59 /// module. 60 void addTypeMapping(Type *DstTy, Type *SrcTy); 61 62 /// linkDefinedTypeBodies - Produce a body for an opaque type in the dest 63 /// module from a type definition in the source module. 64 void linkDefinedTypeBodies(); 65 66 /// get - Return the mapped type to use for the specified input type from the 67 /// source module. 68 Type *get(Type *SrcTy); 69 70 FunctionType *get(FunctionType *T) {return cast<FunctionType>(get((Type*)T));} 71 72 /// dump - Dump out the type map for debugging purposes. 73 void dump() const { 74 for (DenseMap<Type*, Type*>::const_iterator 75 I = MappedTypes.begin(), E = MappedTypes.end(); I != E; ++I) { 76 dbgs() << "TypeMap: "; 77 I->first->dump(); 78 dbgs() << " => "; 79 I->second->dump(); 80 dbgs() << '\n'; 81 } 82 } 83 84private: 85 Type *getImpl(Type *T); 86 /// remapType - Implement the ValueMapTypeRemapper interface. 87 Type *remapType(Type *SrcTy) { 88 return get(SrcTy); 89 } 90 91 bool areTypesIsomorphic(Type *DstTy, Type *SrcTy); 92}; 93} 94 95void TypeMapTy::addTypeMapping(Type *DstTy, Type *SrcTy) { 96 Type *&Entry = MappedTypes[SrcTy]; 97 if (Entry) return; 98 99 if (DstTy == SrcTy) { 100 Entry = DstTy; 101 return; 102 } 103 104 // Check to see if these types are recursively isomorphic and establish a 105 // mapping between them if so. 106 if (!areTypesIsomorphic(DstTy, SrcTy)) { 107 // Oops, they aren't isomorphic. Just discard this request by rolling out 108 // any speculative mappings we've established. 109 for (unsigned i = 0, e = SpeculativeTypes.size(); i != e; ++i) 110 MappedTypes.erase(SpeculativeTypes[i]); 111 } 112 SpeculativeTypes.clear(); 113} 114 115/// areTypesIsomorphic - Recursively walk this pair of types, returning true 116/// if they are isomorphic, false if they are not. 117bool TypeMapTy::areTypesIsomorphic(Type *DstTy, Type *SrcTy) { 118 // Two types with differing kinds are clearly not isomorphic. 119 if (DstTy->getTypeID() != SrcTy->getTypeID()) return false; 120 121 // If we have an entry in the MappedTypes table, then we have our answer. 122 Type *&Entry = MappedTypes[SrcTy]; 123 if (Entry) 124 return Entry == DstTy; 125 126 // Two identical types are clearly isomorphic. Remember this 127 // non-speculatively. 128 if (DstTy == SrcTy) { 129 Entry = DstTy; 130 return true; 131 } 132 133 // Okay, we have two types with identical kinds that we haven't seen before. 134 135 // If this is an opaque struct type, special case it. 136 if (StructType *SSTy = dyn_cast<StructType>(SrcTy)) { 137 // Mapping an opaque type to any struct, just keep the dest struct. 138 if (SSTy->isOpaque()) { 139 Entry = DstTy; 140 SpeculativeTypes.push_back(SrcTy); 141 return true; 142 } 143 144 // Mapping a non-opaque source type to an opaque dest. If this is the first 145 // type that we're mapping onto this destination type then we succeed. Keep 146 // the dest, but fill it in later. This doesn't need to be speculative. If 147 // this is the second (different) type that we're trying to map onto the 148 // same opaque type then we fail. 149 if (cast<StructType>(DstTy)->isOpaque()) { 150 // We can only map one source type onto the opaque destination type. 151 if (!DstResolvedOpaqueTypes.insert(cast<StructType>(DstTy))) 152 return false; 153 SrcDefinitionsToResolve.push_back(SSTy); 154 Entry = DstTy; 155 return true; 156 } 157 } 158 159 // If the number of subtypes disagree between the two types, then we fail. 160 if (SrcTy->getNumContainedTypes() != DstTy->getNumContainedTypes()) 161 return false; 162 163 // Fail if any of the extra properties (e.g. array size) of the type disagree. 164 if (isa<IntegerType>(DstTy)) 165 return false; // bitwidth disagrees. 166 if (PointerType *PT = dyn_cast<PointerType>(DstTy)) { 167 if (PT->getAddressSpace() != cast<PointerType>(SrcTy)->getAddressSpace()) 168 return false; 169 170 } else if (FunctionType *FT = dyn_cast<FunctionType>(DstTy)) { 171 if (FT->isVarArg() != cast<FunctionType>(SrcTy)->isVarArg()) 172 return false; 173 } else if (StructType *DSTy = dyn_cast<StructType>(DstTy)) { 174 StructType *SSTy = cast<StructType>(SrcTy); 175 if (DSTy->isLiteral() != SSTy->isLiteral() || 176 DSTy->isPacked() != SSTy->isPacked()) 177 return false; 178 } else if (ArrayType *DATy = dyn_cast<ArrayType>(DstTy)) { 179 if (DATy->getNumElements() != cast<ArrayType>(SrcTy)->getNumElements()) 180 return false; 181 } else if (VectorType *DVTy = dyn_cast<VectorType>(DstTy)) { 182 if (DVTy->getNumElements() != cast<ArrayType>(SrcTy)->getNumElements()) 183 return false; 184 } 185 186 // Otherwise, we speculate that these two types will line up and recursively 187 // check the subelements. 188 Entry = DstTy; 189 SpeculativeTypes.push_back(SrcTy); 190 191 for (unsigned i = 0, e = SrcTy->getNumContainedTypes(); i != e; ++i) 192 if (!areTypesIsomorphic(DstTy->getContainedType(i), 193 SrcTy->getContainedType(i))) 194 return false; 195 196 // If everything seems to have lined up, then everything is great. 197 return true; 198} 199 200/// linkDefinedTypeBodies - Produce a body for an opaque type in the dest 201/// module from a type definition in the source module. 202void TypeMapTy::linkDefinedTypeBodies() { 203 SmallVector<Type*, 16> Elements; 204 SmallString<16> TmpName; 205 206 // Note that processing entries in this loop (calling 'get') can add new 207 // entries to the SrcDefinitionsToResolve vector. 208 while (!SrcDefinitionsToResolve.empty()) { 209 StructType *SrcSTy = SrcDefinitionsToResolve.pop_back_val(); 210 StructType *DstSTy = cast<StructType>(MappedTypes[SrcSTy]); 211 212 // TypeMap is a many-to-one mapping, if there were multiple types that 213 // provide a body for DstSTy then previous iterations of this loop may have 214 // already handled it. Just ignore this case. 215 if (!DstSTy->isOpaque()) continue; 216 assert(!SrcSTy->isOpaque() && "Not resolving a definition?"); 217 218 // Map the body of the source type over to a new body for the dest type. 219 Elements.resize(SrcSTy->getNumElements()); 220 for (unsigned i = 0, e = Elements.size(); i != e; ++i) 221 Elements[i] = getImpl(SrcSTy->getElementType(i)); 222 223 DstSTy->setBody(Elements, SrcSTy->isPacked()); 224 225 // If DstSTy has no name or has a longer name than STy, then viciously steal 226 // STy's name. 227 if (!SrcSTy->hasName()) continue; 228 StringRef SrcName = SrcSTy->getName(); 229 230 if (!DstSTy->hasName() || DstSTy->getName().size() > SrcName.size()) { 231 TmpName.insert(TmpName.end(), SrcName.begin(), SrcName.end()); 232 SrcSTy->setName(""); 233 DstSTy->setName(TmpName.str()); 234 TmpName.clear(); 235 } 236 } 237 238 DstResolvedOpaqueTypes.clear(); 239} 240 241/// get - Return the mapped type to use for the specified input type from the 242/// source module. 243Type *TypeMapTy::get(Type *Ty) { 244 Type *Result = getImpl(Ty); 245 246 // If this caused a reference to any struct type, resolve it before returning. 247 if (!SrcDefinitionsToResolve.empty()) 248 linkDefinedTypeBodies(); 249 return Result; 250} 251 252/// getImpl - This is the recursive version of get(). 253Type *TypeMapTy::getImpl(Type *Ty) { 254 // If we already have an entry for this type, return it. 255 Type **Entry = &MappedTypes[Ty]; 256 if (*Entry) return *Entry; 257 258 // If this is not a named struct type, then just map all of the elements and 259 // then rebuild the type from inside out. 260 if (!isa<StructType>(Ty) || cast<StructType>(Ty)->isLiteral()) { 261 // If there are no element types to map, then the type is itself. This is 262 // true for the anonymous {} struct, things like 'float', integers, etc. 263 if (Ty->getNumContainedTypes() == 0) 264 return *Entry = Ty; 265 266 // Remap all of the elements, keeping track of whether any of them change. 267 bool AnyChange = false; 268 SmallVector<Type*, 4> ElementTypes; 269 ElementTypes.resize(Ty->getNumContainedTypes()); 270 for (unsigned i = 0, e = Ty->getNumContainedTypes(); i != e; ++i) { 271 ElementTypes[i] = getImpl(Ty->getContainedType(i)); 272 AnyChange |= ElementTypes[i] != Ty->getContainedType(i); 273 } 274 275 // If we found our type while recursively processing stuff, just use it. 276 Entry = &MappedTypes[Ty]; 277 if (*Entry) return *Entry; 278 279 // If all of the element types mapped directly over, then the type is usable 280 // as-is. 281 if (!AnyChange) 282 return *Entry = Ty; 283 284 // Otherwise, rebuild a modified type. 285 switch (Ty->getTypeID()) { 286 default: llvm_unreachable("unknown derived type to remap"); 287 case Type::ArrayTyID: 288 return *Entry = ArrayType::get(ElementTypes[0], 289 cast<ArrayType>(Ty)->getNumElements()); 290 case Type::VectorTyID: 291 return *Entry = VectorType::get(ElementTypes[0], 292 cast<VectorType>(Ty)->getNumElements()); 293 case Type::PointerTyID: 294 return *Entry = PointerType::get(ElementTypes[0], 295 cast<PointerType>(Ty)->getAddressSpace()); 296 case Type::FunctionTyID: 297 return *Entry = FunctionType::get(ElementTypes[0], 298 makeArrayRef(ElementTypes).slice(1), 299 cast<FunctionType>(Ty)->isVarArg()); 300 case Type::StructTyID: 301 // Note that this is only reached for anonymous structs. 302 return *Entry = StructType::get(Ty->getContext(), ElementTypes, 303 cast<StructType>(Ty)->isPacked()); 304 } 305 } 306 307 // Otherwise, this is an unmapped named struct. If the struct can be directly 308 // mapped over, just use it as-is. This happens in a case when the linked-in 309 // module has something like: 310 // %T = type {%T*, i32} 311 // @GV = global %T* null 312 // where T does not exist at all in the destination module. 313 // 314 // The other case we watch for is when the type is not in the destination 315 // module, but that it has to be rebuilt because it refers to something that 316 // is already mapped. For example, if the destination module has: 317 // %A = type { i32 } 318 // and the source module has something like 319 // %A' = type { i32 } 320 // %B = type { %A'* } 321 // @GV = global %B* null 322 // then we want to create a new type: "%B = type { %A*}" and have it take the 323 // pristine "%B" name from the source module. 324 // 325 // To determine which case this is, we have to recursively walk the type graph 326 // speculating that we'll be able to reuse it unmodified. Only if this is 327 // safe would we map the entire thing over. Because this is an optimization, 328 // and is not required for the prettiness of the linked module, we just skip 329 // it and always rebuild a type here. 330 StructType *STy = cast<StructType>(Ty); 331 332 // If the type is opaque, we can just use it directly. 333 if (STy->isOpaque()) 334 return *Entry = STy; 335 336 // Otherwise we create a new type and resolve its body later. This will be 337 // resolved by the top level of get(). 338 SrcDefinitionsToResolve.push_back(STy); 339 StructType *DTy = StructType::create(STy->getContext()); 340 DstResolvedOpaqueTypes.insert(DTy); 341 return *Entry = DTy; 342} 343 344//===----------------------------------------------------------------------===// 345// ModuleLinker implementation. 346//===----------------------------------------------------------------------===// 347 348namespace { 349 /// ModuleLinker - This is an implementation class for the LinkModules 350 /// function, which is the entrypoint for this file. 351 class ModuleLinker { 352 Module *DstM, *SrcM; 353 354 TypeMapTy TypeMap; 355 356 /// ValueMap - Mapping of values from what they used to be in Src, to what 357 /// they are now in DstM. ValueToValueMapTy is a ValueMap, which involves 358 /// some overhead due to the use of Value handles which the Linker doesn't 359 /// actually need, but this allows us to reuse the ValueMapper code. 360 ValueToValueMapTy ValueMap; 361 362 struct AppendingVarInfo { 363 GlobalVariable *NewGV; // New aggregate global in dest module. 364 Constant *DstInit; // Old initializer from dest module. 365 Constant *SrcInit; // Old initializer from src module. 366 }; 367 368 std::vector<AppendingVarInfo> AppendingVars; 369 370 unsigned Mode; // Mode to treat source module. 371 372 // Set of items not to link in from source. 373 SmallPtrSet<const Value*, 16> DoNotLinkFromSource; 374 375 // Vector of functions to lazily link in. 376 std::vector<Function*> LazilyLinkFunctions; 377 378 public: 379 std::string ErrorMsg; 380 381 ModuleLinker(Module *dstM, Module *srcM, unsigned mode) 382 : DstM(dstM), SrcM(srcM), Mode(mode) { } 383 384 bool run(); 385 386 private: 387 /// emitError - Helper method for setting a message and returning an error 388 /// code. 389 bool emitError(const Twine &Message) { 390 ErrorMsg = Message.str(); 391 return true; 392 } 393 394 /// getLinkageResult - This analyzes the two global values and determines 395 /// what the result will look like in the destination module. 396 bool getLinkageResult(GlobalValue *Dest, const GlobalValue *Src, 397 GlobalValue::LinkageTypes <, 398 GlobalValue::VisibilityTypes &Vis, 399 bool &LinkFromSrc); 400 401 /// getLinkedToGlobal - Given a global in the source module, return the 402 /// global in the destination module that is being linked to, if any. 403 GlobalValue *getLinkedToGlobal(GlobalValue *SrcGV) { 404 // If the source has no name it can't link. If it has local linkage, 405 // there is no name match-up going on. 406 if (!SrcGV->hasName() || SrcGV->hasLocalLinkage()) 407 return 0; 408 409 // Otherwise see if we have a match in the destination module's symtab. 410 GlobalValue *DGV = DstM->getNamedValue(SrcGV->getName()); 411 if (DGV == 0) return 0; 412 413 // If we found a global with the same name in the dest module, but it has 414 // internal linkage, we are really not doing any linkage here. 415 if (DGV->hasLocalLinkage()) 416 return 0; 417 418 // Otherwise, we do in fact link to the destination global. 419 return DGV; 420 } 421 422 void computeTypeMapping(); 423 bool categorizeModuleFlagNodes(const NamedMDNode *ModFlags, 424 DenseMap<MDString*, MDNode*> &ErrorNode, 425 DenseMap<MDString*, MDNode*> &WarningNode, 426 DenseMap<MDString*, MDNode*> &OverrideNode, 427 DenseMap<MDString*, 428 SmallSetVector<MDNode*, 8> > &RequireNodes, 429 SmallSetVector<MDString*, 16> &SeenIDs); 430 431 bool linkAppendingVarProto(GlobalVariable *DstGV, GlobalVariable *SrcGV); 432 bool linkGlobalProto(GlobalVariable *SrcGV); 433 bool linkFunctionProto(Function *SrcF); 434 bool linkAliasProto(GlobalAlias *SrcA); 435 bool linkModuleFlagsMetadata(); 436 437 void linkAppendingVarInit(const AppendingVarInfo &AVI); 438 void linkGlobalInits(); 439 void linkFunctionBody(Function *Dst, Function *Src); 440 void linkAliasBodies(); 441 void linkNamedMDNodes(); 442 }; 443} 444 445/// forceRenaming - The LLVM SymbolTable class autorenames globals that conflict 446/// in the symbol table. This is good for all clients except for us. Go 447/// through the trouble to force this back. 448static void forceRenaming(GlobalValue *GV, StringRef Name) { 449 // If the global doesn't force its name or if it already has the right name, 450 // there is nothing for us to do. 451 if (GV->hasLocalLinkage() || GV->getName() == Name) 452 return; 453 454 Module *M = GV->getParent(); 455 456 // If there is a conflict, rename the conflict. 457 if (GlobalValue *ConflictGV = M->getNamedValue(Name)) { 458 GV->takeName(ConflictGV); 459 ConflictGV->setName(Name); // This will cause ConflictGV to get renamed 460 assert(ConflictGV->getName() != Name && "forceRenaming didn't work"); 461 } else { 462 GV->setName(Name); // Force the name back 463 } 464} 465 466/// copyGVAttributes - copy additional attributes (those not needed to construct 467/// a GlobalValue) from the SrcGV to the DestGV. 468static void copyGVAttributes(GlobalValue *DestGV, const GlobalValue *SrcGV) { 469 // Use the maximum alignment, rather than just copying the alignment of SrcGV. 470 unsigned Alignment = std::max(DestGV->getAlignment(), SrcGV->getAlignment()); 471 DestGV->copyAttributesFrom(SrcGV); 472 DestGV->setAlignment(Alignment); 473 474 forceRenaming(DestGV, SrcGV->getName()); 475} 476 477static bool isLessConstraining(GlobalValue::VisibilityTypes a, 478 GlobalValue::VisibilityTypes b) { 479 if (a == GlobalValue::HiddenVisibility) 480 return false; 481 if (b == GlobalValue::HiddenVisibility) 482 return true; 483 if (a == GlobalValue::ProtectedVisibility) 484 return false; 485 if (b == GlobalValue::ProtectedVisibility) 486 return true; 487 return false; 488} 489 490/// getLinkageResult - This analyzes the two global values and determines what 491/// the result will look like in the destination module. In particular, it 492/// computes the resultant linkage type and visibility, computes whether the 493/// global in the source should be copied over to the destination (replacing 494/// the existing one), and computes whether this linkage is an error or not. 495bool ModuleLinker::getLinkageResult(GlobalValue *Dest, const GlobalValue *Src, 496 GlobalValue::LinkageTypes <, 497 GlobalValue::VisibilityTypes &Vis, 498 bool &LinkFromSrc) { 499 assert(Dest && "Must have two globals being queried"); 500 assert(!Src->hasLocalLinkage() && 501 "If Src has internal linkage, Dest shouldn't be set!"); 502 503 bool SrcIsDeclaration = Src->isDeclaration() && !Src->isMaterializable(); 504 bool DestIsDeclaration = Dest->isDeclaration(); 505 506 if (SrcIsDeclaration) { 507 // If Src is external or if both Src & Dest are external.. Just link the 508 // external globals, we aren't adding anything. 509 if (Src->hasDLLImportLinkage()) { 510 // If one of GVs has DLLImport linkage, result should be dllimport'ed. 511 if (DestIsDeclaration) { 512 LinkFromSrc = true; 513 LT = Src->getLinkage(); 514 } 515 } else if (Dest->hasExternalWeakLinkage()) { 516 // If the Dest is weak, use the source linkage. 517 LinkFromSrc = true; 518 LT = Src->getLinkage(); 519 } else { 520 LinkFromSrc = false; 521 LT = Dest->getLinkage(); 522 } 523 } else if (DestIsDeclaration && !Dest->hasDLLImportLinkage()) { 524 // If Dest is external but Src is not: 525 LinkFromSrc = true; 526 LT = Src->getLinkage(); 527 } else if (Src->isWeakForLinker()) { 528 // At this point we know that Dest has LinkOnce, External*, Weak, Common, 529 // or DLL* linkage. 530 if (Dest->hasExternalWeakLinkage() || 531 Dest->hasAvailableExternallyLinkage() || 532 (Dest->hasLinkOnceLinkage() && 533 (Src->hasWeakLinkage() || Src->hasCommonLinkage()))) { 534 LinkFromSrc = true; 535 LT = Src->getLinkage(); 536 } else { 537 LinkFromSrc = false; 538 LT = Dest->getLinkage(); 539 } 540 } else if (Dest->isWeakForLinker()) { 541 // At this point we know that Src has External* or DLL* linkage. 542 if (Src->hasExternalWeakLinkage()) { 543 LinkFromSrc = false; 544 LT = Dest->getLinkage(); 545 } else { 546 LinkFromSrc = true; 547 LT = GlobalValue::ExternalLinkage; 548 } 549 } else { 550 assert((Dest->hasExternalLinkage() || Dest->hasDLLImportLinkage() || 551 Dest->hasDLLExportLinkage() || Dest->hasExternalWeakLinkage()) && 552 (Src->hasExternalLinkage() || Src->hasDLLImportLinkage() || 553 Src->hasDLLExportLinkage() || Src->hasExternalWeakLinkage()) && 554 "Unexpected linkage type!"); 555 return emitError("Linking globals named '" + Src->getName() + 556 "': symbol multiply defined!"); 557 } 558 559 // Compute the visibility. We follow the rules in the System V Application 560 // Binary Interface. 561 Vis = isLessConstraining(Src->getVisibility(), Dest->getVisibility()) ? 562 Dest->getVisibility() : Src->getVisibility(); 563 return false; 564} 565 566/// computeTypeMapping - Loop over all of the linked values to compute type 567/// mappings. For example, if we link "extern Foo *x" and "Foo *x = NULL", then 568/// we have two struct types 'Foo' but one got renamed when the module was 569/// loaded into the same LLVMContext. 570void ModuleLinker::computeTypeMapping() { 571 // Incorporate globals. 572 for (Module::global_iterator I = SrcM->global_begin(), 573 E = SrcM->global_end(); I != E; ++I) { 574 GlobalValue *DGV = getLinkedToGlobal(I); 575 if (DGV == 0) continue; 576 577 if (!DGV->hasAppendingLinkage() || !I->hasAppendingLinkage()) { 578 TypeMap.addTypeMapping(DGV->getType(), I->getType()); 579 continue; 580 } 581 582 // Unify the element type of appending arrays. 583 ArrayType *DAT = cast<ArrayType>(DGV->getType()->getElementType()); 584 ArrayType *SAT = cast<ArrayType>(I->getType()->getElementType()); 585 TypeMap.addTypeMapping(DAT->getElementType(), SAT->getElementType()); 586 } 587 588 // Incorporate functions. 589 for (Module::iterator I = SrcM->begin(), E = SrcM->end(); I != E; ++I) { 590 if (GlobalValue *DGV = getLinkedToGlobal(I)) 591 TypeMap.addTypeMapping(DGV->getType(), I->getType()); 592 } 593 594 // Incorporate types by name, scanning all the types in the source module. 595 // At this point, the destination module may have a type "%foo = { i32 }" for 596 // example. When the source module got loaded into the same LLVMContext, if 597 // it had the same type, it would have been renamed to "%foo.42 = { i32 }". 598 std::vector<StructType*> SrcStructTypes; 599 SrcM->findUsedStructTypes(SrcStructTypes, true); 600 SmallPtrSet<StructType*, 32> SrcStructTypesSet(SrcStructTypes.begin(), 601 SrcStructTypes.end()); 602 603 std::vector<StructType*> DstStructTypes; 604 DstM->findUsedStructTypes(DstStructTypes, true); 605 SmallPtrSet<StructType*, 32> DstStructTypesSet(DstStructTypes.begin(), 606 DstStructTypes.end()); 607 608 for (unsigned i = 0, e = SrcStructTypes.size(); i != e; ++i) { 609 StructType *ST = SrcStructTypes[i]; 610 if (!ST->hasName()) continue; 611 612 // Check to see if there is a dot in the name followed by a digit. 613 size_t DotPos = ST->getName().rfind('.'); 614 if (DotPos == 0 || DotPos == StringRef::npos || 615 ST->getName().back() == '.' || !isdigit(ST->getName()[DotPos+1])) 616 continue; 617 618 // Check to see if the destination module has a struct with the prefix name. 619 if (StructType *DST = DstM->getTypeByName(ST->getName().substr(0, DotPos))) 620 // Don't use it if this actually came from the source module. They're in 621 // the same LLVMContext after all. Also don't use it unless the type is 622 // actually used in the destination module. This can happen in situations 623 // like this: 624 // 625 // Module A Module B 626 // -------- -------- 627 // %Z = type { %A } %B = type { %C.1 } 628 // %A = type { %B.1, [7 x i8] } %C.1 = type { i8* } 629 // %B.1 = type { %C } %A.2 = type { %B.3, [5 x i8] } 630 // %C = type { i8* } %B.3 = type { %C.1 } 631 // 632 // When we link Module B with Module A, the '%B' in Module B is 633 // used. However, that would then use '%C.1'. But when we process '%C.1', 634 // we prefer to take the '%C' version. So we are then left with both 635 // '%C.1' and '%C' being used for the same types. This leads to some 636 // variables using one type and some using the other. 637 if (!SrcStructTypesSet.count(DST) && DstStructTypesSet.count(DST)) 638 TypeMap.addTypeMapping(DST, ST); 639 } 640 641 // Don't bother incorporating aliases, they aren't generally typed well. 642 643 // Now that we have discovered all of the type equivalences, get a body for 644 // any 'opaque' types in the dest module that are now resolved. 645 TypeMap.linkDefinedTypeBodies(); 646} 647 648/// linkAppendingVarProto - If there were any appending global variables, link 649/// them together now. Return true on error. 650bool ModuleLinker::linkAppendingVarProto(GlobalVariable *DstGV, 651 GlobalVariable *SrcGV) { 652 653 if (!SrcGV->hasAppendingLinkage() || !DstGV->hasAppendingLinkage()) 654 return emitError("Linking globals named '" + SrcGV->getName() + 655 "': can only link appending global with another appending global!"); 656 657 ArrayType *DstTy = cast<ArrayType>(DstGV->getType()->getElementType()); 658 ArrayType *SrcTy = 659 cast<ArrayType>(TypeMap.get(SrcGV->getType()->getElementType())); 660 Type *EltTy = DstTy->getElementType(); 661 662 // Check to see that they two arrays agree on type. 663 if (EltTy != SrcTy->getElementType()) 664 return emitError("Appending variables with different element types!"); 665 if (DstGV->isConstant() != SrcGV->isConstant()) 666 return emitError("Appending variables linked with different const'ness!"); 667 668 if (DstGV->getAlignment() != SrcGV->getAlignment()) 669 return emitError( 670 "Appending variables with different alignment need to be linked!"); 671 672 if (DstGV->getVisibility() != SrcGV->getVisibility()) 673 return emitError( 674 "Appending variables with different visibility need to be linked!"); 675 676 if (DstGV->getSection() != SrcGV->getSection()) 677 return emitError( 678 "Appending variables with different section name need to be linked!"); 679 680 uint64_t NewSize = DstTy->getNumElements() + SrcTy->getNumElements(); 681 ArrayType *NewType = ArrayType::get(EltTy, NewSize); 682 683 // Create the new global variable. 684 GlobalVariable *NG = 685 new GlobalVariable(*DstGV->getParent(), NewType, SrcGV->isConstant(), 686 DstGV->getLinkage(), /*init*/0, /*name*/"", DstGV, 687 DstGV->isThreadLocal(), 688 DstGV->getType()->getAddressSpace()); 689 690 // Propagate alignment, visibility and section info. 691 copyGVAttributes(NG, DstGV); 692 693 AppendingVarInfo AVI; 694 AVI.NewGV = NG; 695 AVI.DstInit = DstGV->getInitializer(); 696 AVI.SrcInit = SrcGV->getInitializer(); 697 AppendingVars.push_back(AVI); 698 699 // Replace any uses of the two global variables with uses of the new 700 // global. 701 ValueMap[SrcGV] = ConstantExpr::getBitCast(NG, TypeMap.get(SrcGV->getType())); 702 703 DstGV->replaceAllUsesWith(ConstantExpr::getBitCast(NG, DstGV->getType())); 704 DstGV->eraseFromParent(); 705 706 // Track the source variable so we don't try to link it. 707 DoNotLinkFromSource.insert(SrcGV); 708 709 return false; 710} 711 712/// linkGlobalProto - Loop through the global variables in the src module and 713/// merge them into the dest module. 714bool ModuleLinker::linkGlobalProto(GlobalVariable *SGV) { 715 GlobalValue *DGV = getLinkedToGlobal(SGV); 716 llvm::Optional<GlobalValue::VisibilityTypes> NewVisibility; 717 718 if (DGV) { 719 // Concatenation of appending linkage variables is magic and handled later. 720 if (DGV->hasAppendingLinkage() || SGV->hasAppendingLinkage()) 721 return linkAppendingVarProto(cast<GlobalVariable>(DGV), SGV); 722 723 // Determine whether linkage of these two globals follows the source 724 // module's definition or the destination module's definition. 725 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; 726 GlobalValue::VisibilityTypes NV; 727 bool LinkFromSrc = false; 728 if (getLinkageResult(DGV, SGV, NewLinkage, NV, LinkFromSrc)) 729 return true; 730 NewVisibility = NV; 731 732 // If we're not linking from the source, then keep the definition that we 733 // have. 734 if (!LinkFromSrc) { 735 // Special case for const propagation. 736 if (GlobalVariable *DGVar = dyn_cast<GlobalVariable>(DGV)) 737 if (DGVar->isDeclaration() && SGV->isConstant() && !DGVar->isConstant()) 738 DGVar->setConstant(true); 739 740 // Set calculated linkage and visibility. 741 DGV->setLinkage(NewLinkage); 742 DGV->setVisibility(*NewVisibility); 743 744 // Make sure to remember this mapping. 745 ValueMap[SGV] = ConstantExpr::getBitCast(DGV,TypeMap.get(SGV->getType())); 746 747 // Track the source global so that we don't attempt to copy it over when 748 // processing global initializers. 749 DoNotLinkFromSource.insert(SGV); 750 751 return false; 752 } 753 } 754 755 // No linking to be performed or linking from the source: simply create an 756 // identical version of the symbol over in the dest module... the 757 // initializer will be filled in later by LinkGlobalInits. 758 GlobalVariable *NewDGV = 759 new GlobalVariable(*DstM, TypeMap.get(SGV->getType()->getElementType()), 760 SGV->isConstant(), SGV->getLinkage(), /*init*/0, 761 SGV->getName(), /*insertbefore*/0, 762 SGV->isThreadLocal(), 763 SGV->getType()->getAddressSpace()); 764 // Propagate alignment, visibility and section info. 765 copyGVAttributes(NewDGV, SGV); 766 if (NewVisibility) 767 NewDGV->setVisibility(*NewVisibility); 768 769 if (DGV) { 770 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDGV, DGV->getType())); 771 DGV->eraseFromParent(); 772 } 773 774 // Make sure to remember this mapping. 775 ValueMap[SGV] = NewDGV; 776 return false; 777} 778 779/// linkFunctionProto - Link the function in the source module into the 780/// destination module if needed, setting up mapping information. 781bool ModuleLinker::linkFunctionProto(Function *SF) { 782 GlobalValue *DGV = getLinkedToGlobal(SF); 783 llvm::Optional<GlobalValue::VisibilityTypes> NewVisibility; 784 785 if (DGV) { 786 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; 787 bool LinkFromSrc = false; 788 GlobalValue::VisibilityTypes NV; 789 if (getLinkageResult(DGV, SF, NewLinkage, NV, LinkFromSrc)) 790 return true; 791 NewVisibility = NV; 792 793 if (!LinkFromSrc) { 794 // Set calculated linkage 795 DGV->setLinkage(NewLinkage); 796 DGV->setVisibility(*NewVisibility); 797 798 // Make sure to remember this mapping. 799 ValueMap[SF] = ConstantExpr::getBitCast(DGV, TypeMap.get(SF->getType())); 800 801 // Track the function from the source module so we don't attempt to remap 802 // it. 803 DoNotLinkFromSource.insert(SF); 804 805 return false; 806 } 807 } 808 809 // If there is no linkage to be performed or we are linking from the source, 810 // bring SF over. 811 Function *NewDF = Function::Create(TypeMap.get(SF->getFunctionType()), 812 SF->getLinkage(), SF->getName(), DstM); 813 copyGVAttributes(NewDF, SF); 814 if (NewVisibility) 815 NewDF->setVisibility(*NewVisibility); 816 817 if (DGV) { 818 // Any uses of DF need to change to NewDF, with cast. 819 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDF, DGV->getType())); 820 DGV->eraseFromParent(); 821 } else { 822 // Internal, LO_ODR, or LO linkage - stick in set to ignore and lazily link. 823 if (SF->hasLocalLinkage() || SF->hasLinkOnceLinkage() || 824 SF->hasAvailableExternallyLinkage()) { 825 DoNotLinkFromSource.insert(SF); 826 LazilyLinkFunctions.push_back(SF); 827 } 828 } 829 830 ValueMap[SF] = NewDF; 831 return false; 832} 833 834/// LinkAliasProto - Set up prototypes for any aliases that come over from the 835/// source module. 836bool ModuleLinker::linkAliasProto(GlobalAlias *SGA) { 837 GlobalValue *DGV = getLinkedToGlobal(SGA); 838 llvm::Optional<GlobalValue::VisibilityTypes> NewVisibility; 839 840 if (DGV) { 841 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; 842 GlobalValue::VisibilityTypes NV; 843 bool LinkFromSrc = false; 844 if (getLinkageResult(DGV, SGA, NewLinkage, NV, LinkFromSrc)) 845 return true; 846 NewVisibility = NV; 847 848 if (!LinkFromSrc) { 849 // Set calculated linkage. 850 DGV->setLinkage(NewLinkage); 851 DGV->setVisibility(*NewVisibility); 852 853 // Make sure to remember this mapping. 854 ValueMap[SGA] = ConstantExpr::getBitCast(DGV,TypeMap.get(SGA->getType())); 855 856 // Track the alias from the source module so we don't attempt to remap it. 857 DoNotLinkFromSource.insert(SGA); 858 859 return false; 860 } 861 } 862 863 // If there is no linkage to be performed or we're linking from the source, 864 // bring over SGA. 865 GlobalAlias *NewDA = new GlobalAlias(TypeMap.get(SGA->getType()), 866 SGA->getLinkage(), SGA->getName(), 867 /*aliasee*/0, DstM); 868 copyGVAttributes(NewDA, SGA); 869 if (NewVisibility) 870 NewDA->setVisibility(*NewVisibility); 871 872 if (DGV) { 873 // Any uses of DGV need to change to NewDA, with cast. 874 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDA, DGV->getType())); 875 DGV->eraseFromParent(); 876 } 877 878 ValueMap[SGA] = NewDA; 879 return false; 880} 881 882static void getArrayElements(Constant *C, SmallVectorImpl<Constant*> &Dest) { 883 unsigned NumElements = cast<ArrayType>(C->getType())->getNumElements(); 884 885 for (unsigned i = 0; i != NumElements; ++i) 886 Dest.push_back(C->getAggregateElement(i)); 887} 888 889void ModuleLinker::linkAppendingVarInit(const AppendingVarInfo &AVI) { 890 // Merge the initializer. 891 SmallVector<Constant*, 16> Elements; 892 getArrayElements(AVI.DstInit, Elements); 893 894 Constant *SrcInit = MapValue(AVI.SrcInit, ValueMap, RF_None, &TypeMap); 895 getArrayElements(SrcInit, Elements); 896 897 ArrayType *NewType = cast<ArrayType>(AVI.NewGV->getType()->getElementType()); 898 AVI.NewGV->setInitializer(ConstantArray::get(NewType, Elements)); 899} 900 901/// linkGlobalInits - Update the initializers in the Dest module now that all 902/// globals that may be referenced are in Dest. 903void ModuleLinker::linkGlobalInits() { 904 // Loop over all of the globals in the src module, mapping them over as we go 905 for (Module::const_global_iterator I = SrcM->global_begin(), 906 E = SrcM->global_end(); I != E; ++I) { 907 908 // Only process initialized GV's or ones not already in dest. 909 if (!I->hasInitializer() || DoNotLinkFromSource.count(I)) continue; 910 911 // Grab destination global variable. 912 GlobalVariable *DGV = cast<GlobalVariable>(ValueMap[I]); 913 // Figure out what the initializer looks like in the dest module. 914 DGV->setInitializer(MapValue(I->getInitializer(), ValueMap, 915 RF_None, &TypeMap)); 916 } 917} 918 919/// linkFunctionBody - Copy the source function over into the dest function and 920/// fix up references to values. At this point we know that Dest is an external 921/// function, and that Src is not. 922void ModuleLinker::linkFunctionBody(Function *Dst, Function *Src) { 923 assert(Src && Dst && Dst->isDeclaration() && !Src->isDeclaration()); 924 925 // Go through and convert function arguments over, remembering the mapping. 926 Function::arg_iterator DI = Dst->arg_begin(); 927 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end(); 928 I != E; ++I, ++DI) { 929 DI->setName(I->getName()); // Copy the name over. 930 931 // Add a mapping to our mapping. 932 ValueMap[I] = DI; 933 } 934 935 if (Mode == Linker::DestroySource) { 936 // Splice the body of the source function into the dest function. 937 Dst->getBasicBlockList().splice(Dst->end(), Src->getBasicBlockList()); 938 939 // At this point, all of the instructions and values of the function are now 940 // copied over. The only problem is that they are still referencing values in 941 // the Source function as operands. Loop through all of the operands of the 942 // functions and patch them up to point to the local versions. 943 for (Function::iterator BB = Dst->begin(), BE = Dst->end(); BB != BE; ++BB) 944 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) 945 RemapInstruction(I, ValueMap, RF_IgnoreMissingEntries, &TypeMap); 946 947 } else { 948 // Clone the body of the function into the dest function. 949 SmallVector<ReturnInst*, 8> Returns; // Ignore returns. 950 CloneFunctionInto(Dst, Src, ValueMap, false, Returns, "", NULL, &TypeMap); 951 } 952 953 // There is no need to map the arguments anymore. 954 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end(); 955 I != E; ++I) 956 ValueMap.erase(I); 957 958} 959 960/// linkAliasBodies - Insert all of the aliases in Src into the Dest module. 961void ModuleLinker::linkAliasBodies() { 962 for (Module::alias_iterator I = SrcM->alias_begin(), E = SrcM->alias_end(); 963 I != E; ++I) { 964 if (DoNotLinkFromSource.count(I)) 965 continue; 966 if (Constant *Aliasee = I->getAliasee()) { 967 GlobalAlias *DA = cast<GlobalAlias>(ValueMap[I]); 968 DA->setAliasee(MapValue(Aliasee, ValueMap, RF_None, &TypeMap)); 969 } 970 } 971} 972 973/// linkNamedMDNodes - Insert all of the named MDNodes in Src into the Dest 974/// module. 975void ModuleLinker::linkNamedMDNodes() { 976 const NamedMDNode *SrcModFlags = SrcM->getModuleFlagsMetadata(); 977 for (Module::const_named_metadata_iterator I = SrcM->named_metadata_begin(), 978 E = SrcM->named_metadata_end(); I != E; ++I) { 979 // Don't link module flags here. Do them separately. 980 if (&*I == SrcModFlags) continue; 981 NamedMDNode *DestNMD = DstM->getOrInsertNamedMetadata(I->getName()); 982 // Add Src elements into Dest node. 983 for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) 984 DestNMD->addOperand(MapValue(I->getOperand(i), ValueMap, 985 RF_None, &TypeMap)); 986 } 987} 988 989/// categorizeModuleFlagNodes - Categorize the module flags according to their 990/// type: Error, Warning, Override, and Require. 991bool ModuleLinker:: 992categorizeModuleFlagNodes(const NamedMDNode *ModFlags, 993 DenseMap<MDString*, MDNode*> &ErrorNode, 994 DenseMap<MDString*, MDNode*> &WarningNode, 995 DenseMap<MDString*, MDNode*> &OverrideNode, 996 DenseMap<MDString*, 997 SmallSetVector<MDNode*, 8> > &RequireNodes, 998 SmallSetVector<MDString*, 16> &SeenIDs) { 999 bool HasErr = false; 1000 1001 for (unsigned I = 0, E = ModFlags->getNumOperands(); I != E; ++I) { 1002 MDNode *Op = ModFlags->getOperand(I); 1003 assert(Op->getNumOperands() == 3 && "Invalid module flag metadata!"); 1004 assert(isa<ConstantInt>(Op->getOperand(0)) && 1005 "Module flag's first operand must be an integer!"); 1006 assert(isa<MDString>(Op->getOperand(1)) && 1007 "Module flag's second operand must be an MDString!"); 1008 1009 ConstantInt *Behavior = cast<ConstantInt>(Op->getOperand(0)); 1010 MDString *ID = cast<MDString>(Op->getOperand(1)); 1011 Value *Val = Op->getOperand(2); 1012 switch (Behavior->getZExtValue()) { 1013 default: 1014 assert(false && "Invalid behavior in module flag metadata!"); 1015 break; 1016 case Module::Error: { 1017 MDNode *&ErrNode = ErrorNode[ID]; 1018 if (!ErrNode) ErrNode = Op; 1019 if (ErrNode->getOperand(2) != Val) 1020 HasErr = emitError("linking module flags '" + ID->getString() + 1021 "': IDs have conflicting values"); 1022 break; 1023 } 1024 case Module::Warning: { 1025 MDNode *&WarnNode = WarningNode[ID]; 1026 if (!WarnNode) WarnNode = Op; 1027 if (WarnNode->getOperand(2) != Val) 1028 errs() << "WARNING: linking module flags '" << ID->getString() 1029 << "': IDs have conflicting values"; 1030 break; 1031 } 1032 case Module::Require: RequireNodes[ID].insert(Op); break; 1033 case Module::Override: { 1034 MDNode *&OvrNode = OverrideNode[ID]; 1035 if (!OvrNode) OvrNode = Op; 1036 if (OvrNode->getOperand(2) != Val) 1037 HasErr = emitError("linking module flags '" + ID->getString() + 1038 "': IDs have conflicting override values"); 1039 break; 1040 } 1041 } 1042 1043 SeenIDs.insert(ID); 1044 } 1045 1046 return HasErr; 1047} 1048 1049/// linkModuleFlagsMetadata - Merge the linker flags in Src into the Dest 1050/// module. 1051bool ModuleLinker::linkModuleFlagsMetadata() { 1052 const NamedMDNode *SrcModFlags = SrcM->getModuleFlagsMetadata(); 1053 if (!SrcModFlags) return false; 1054 1055 NamedMDNode *DstModFlags = DstM->getOrInsertModuleFlagsMetadata(); 1056 1057 // If the destination module doesn't have module flags yet, then just copy 1058 // over the source module's flags. 1059 if (DstModFlags->getNumOperands() == 0) { 1060 for (unsigned I = 0, E = SrcModFlags->getNumOperands(); I != E; ++I) 1061 DstModFlags->addOperand(SrcModFlags->getOperand(I)); 1062 1063 return false; 1064 } 1065 1066 bool HasErr = false; 1067 1068 // Otherwise, we have to merge them based on their behaviors. First, 1069 // categorize all of the nodes in the modules' module flags. If an error or 1070 // warning occurs, then emit the appropriate message(s). 1071 DenseMap<MDString*, MDNode*> ErrorNode; 1072 DenseMap<MDString*, MDNode*> WarningNode; 1073 DenseMap<MDString*, MDNode*> OverrideNode; 1074 DenseMap<MDString*, SmallSetVector<MDNode*, 8> > RequireNodes; 1075 SmallSetVector<MDString*, 16> SeenIDs; 1076 1077 HasErr |= categorizeModuleFlagNodes(SrcModFlags, ErrorNode, WarningNode, 1078 OverrideNode, RequireNodes, SeenIDs); 1079 HasErr |= categorizeModuleFlagNodes(DstModFlags, ErrorNode, WarningNode, 1080 OverrideNode, RequireNodes, SeenIDs); 1081 1082 // Check that there isn't both an error and warning node for a flag. 1083 for (SmallSetVector<MDString*, 16>::iterator 1084 I = SeenIDs.begin(), E = SeenIDs.end(); I != E; ++I) { 1085 MDString *ID = *I; 1086 if (ErrorNode[ID] && WarningNode[ID]) 1087 HasErr = emitError("linking module flags '" + ID->getString() + 1088 "': IDs have conflicting behaviors"); 1089 } 1090 1091 // Early exit if we had an error. 1092 if (HasErr) return true; 1093 1094 // Get the destination's module flags ready for new operands. 1095 DstModFlags->dropAllReferences(); 1096 1097 // Add all of the module flags to the destination module. 1098 DenseMap<MDString*, SmallVector<MDNode*, 4> > AddedNodes; 1099 for (SmallSetVector<MDString*, 16>::iterator 1100 I = SeenIDs.begin(), E = SeenIDs.end(); I != E; ++I) { 1101 MDString *ID = *I; 1102 if (OverrideNode[ID]) { 1103 DstModFlags->addOperand(OverrideNode[ID]); 1104 AddedNodes[ID].push_back(OverrideNode[ID]); 1105 } else if (ErrorNode[ID]) { 1106 DstModFlags->addOperand(ErrorNode[ID]); 1107 AddedNodes[ID].push_back(ErrorNode[ID]); 1108 } else if (WarningNode[ID]) { 1109 DstModFlags->addOperand(WarningNode[ID]); 1110 AddedNodes[ID].push_back(WarningNode[ID]); 1111 } 1112 1113 for (SmallSetVector<MDNode*, 8>::iterator 1114 II = RequireNodes[ID].begin(), IE = RequireNodes[ID].end(); 1115 II != IE; ++II) 1116 DstModFlags->addOperand(*II); 1117 } 1118 1119 // Now check that all of the requirements have been satisfied. 1120 for (SmallSetVector<MDString*, 16>::iterator 1121 I = SeenIDs.begin(), E = SeenIDs.end(); I != E; ++I) { 1122 MDString *ID = *I; 1123 SmallSetVector<MDNode*, 8> &Set = RequireNodes[ID]; 1124 1125 for (SmallSetVector<MDNode*, 8>::iterator 1126 II = Set.begin(), IE = Set.end(); II != IE; ++II) { 1127 MDNode *Node = *II; 1128 assert(isa<MDNode>(Node->getOperand(2)) && 1129 "Module flag's third operand must be an MDNode!"); 1130 MDNode *Val = cast<MDNode>(Node->getOperand(2)); 1131 1132 MDString *ReqID = cast<MDString>(Val->getOperand(0)); 1133 Value *ReqVal = Val->getOperand(1); 1134 1135 bool HasValue = false; 1136 for (SmallVectorImpl<MDNode*>::iterator 1137 RI = AddedNodes[ReqID].begin(), RE = AddedNodes[ReqID].end(); 1138 RI != RE; ++RI) { 1139 MDNode *ReqNode = *RI; 1140 if (ReqNode->getOperand(2) == ReqVal) { 1141 HasValue = true; 1142 break; 1143 } 1144 } 1145 1146 if (!HasValue) 1147 HasErr = emitError("linking module flags '" + ReqID->getString() + 1148 "': does not have the required value"); 1149 } 1150 } 1151 1152 return HasErr; 1153} 1154 1155bool ModuleLinker::run() { 1156 assert(DstM && "Null destination module"); 1157 assert(SrcM && "Null source module"); 1158 1159 // Inherit the target data from the source module if the destination module 1160 // doesn't have one already. 1161 if (DstM->getDataLayout().empty() && !SrcM->getDataLayout().empty()) 1162 DstM->setDataLayout(SrcM->getDataLayout()); 1163 1164 // Copy the target triple from the source to dest if the dest's is empty. 1165 if (DstM->getTargetTriple().empty() && !SrcM->getTargetTriple().empty()) 1166 DstM->setTargetTriple(SrcM->getTargetTriple()); 1167 1168 if (!SrcM->getDataLayout().empty() && !DstM->getDataLayout().empty() && 1169 SrcM->getDataLayout() != DstM->getDataLayout()) 1170 errs() << "WARNING: Linking two modules of different data layouts!\n"; 1171 if (!SrcM->getTargetTriple().empty() && 1172 DstM->getTargetTriple() != SrcM->getTargetTriple()) { 1173 errs() << "WARNING: Linking two modules of different target triples: "; 1174 if (!SrcM->getModuleIdentifier().empty()) 1175 errs() << SrcM->getModuleIdentifier() << ": "; 1176 errs() << "'" << SrcM->getTargetTriple() << "' and '" 1177 << DstM->getTargetTriple() << "'\n"; 1178 } 1179 1180 // Append the module inline asm string. 1181 if (!SrcM->getModuleInlineAsm().empty()) { 1182 if (DstM->getModuleInlineAsm().empty()) 1183 DstM->setModuleInlineAsm(SrcM->getModuleInlineAsm()); 1184 else 1185 DstM->setModuleInlineAsm(DstM->getModuleInlineAsm()+"\n"+ 1186 SrcM->getModuleInlineAsm()); 1187 } 1188 1189 // Update the destination module's dependent libraries list with the libraries 1190 // from the source module. There's no opportunity for duplicates here as the 1191 // Module ensures that duplicate insertions are discarded. 1192 for (Module::lib_iterator SI = SrcM->lib_begin(), SE = SrcM->lib_end(); 1193 SI != SE; ++SI) 1194 DstM->addLibrary(*SI); 1195 1196 // If the source library's module id is in the dependent library list of the 1197 // destination library, remove it since that module is now linked in. 1198 StringRef ModuleId = SrcM->getModuleIdentifier(); 1199 if (!ModuleId.empty()) 1200 DstM->removeLibrary(sys::path::stem(ModuleId)); 1201 1202 // Loop over all of the linked values to compute type mappings. 1203 computeTypeMapping(); 1204 1205 // Insert all of the globals in src into the DstM module... without linking 1206 // initializers (which could refer to functions not yet mapped over). 1207 for (Module::global_iterator I = SrcM->global_begin(), 1208 E = SrcM->global_end(); I != E; ++I) 1209 if (linkGlobalProto(I)) 1210 return true; 1211 1212 // Link the functions together between the two modules, without doing function 1213 // bodies... this just adds external function prototypes to the DstM 1214 // function... We do this so that when we begin processing function bodies, 1215 // all of the global values that may be referenced are available in our 1216 // ValueMap. 1217 for (Module::iterator I = SrcM->begin(), E = SrcM->end(); I != E; ++I) 1218 if (linkFunctionProto(I)) 1219 return true; 1220 1221 // If there were any aliases, link them now. 1222 for (Module::alias_iterator I = SrcM->alias_begin(), 1223 E = SrcM->alias_end(); I != E; ++I) 1224 if (linkAliasProto(I)) 1225 return true; 1226 1227 for (unsigned i = 0, e = AppendingVars.size(); i != e; ++i) 1228 linkAppendingVarInit(AppendingVars[i]); 1229 1230 // Update the initializers in the DstM module now that all globals that may 1231 // be referenced are in DstM. 1232 linkGlobalInits(); 1233 1234 // Link in the function bodies that are defined in the source module into 1235 // DstM. 1236 for (Module::iterator SF = SrcM->begin(), E = SrcM->end(); SF != E; ++SF) { 1237 // Skip if not linking from source. 1238 if (DoNotLinkFromSource.count(SF)) continue; 1239 1240 // Skip if no body (function is external) or materialize. 1241 if (SF->isDeclaration()) { 1242 if (!SF->isMaterializable()) 1243 continue; 1244 if (SF->Materialize(&ErrorMsg)) 1245 return true; 1246 } 1247 1248 linkFunctionBody(cast<Function>(ValueMap[SF]), SF); 1249 SF->Dematerialize(); 1250 } 1251 1252 // Resolve all uses of aliases with aliasees. 1253 linkAliasBodies(); 1254 1255 // Remap all of the named MDNodes in Src into the DstM module. We do this 1256 // after linking GlobalValues so that MDNodes that reference GlobalValues 1257 // are properly remapped. 1258 linkNamedMDNodes(); 1259 1260 // Merge the module flags into the DstM module. 1261 if (linkModuleFlagsMetadata()) 1262 return true; 1263 1264 // Process vector of lazily linked in functions. 1265 bool LinkedInAnyFunctions; 1266 do { 1267 LinkedInAnyFunctions = false; 1268 1269 for(std::vector<Function*>::iterator I = LazilyLinkFunctions.begin(), 1270 E = LazilyLinkFunctions.end(); I != E; ++I) { 1271 if (!*I) 1272 continue; 1273 1274 Function *SF = *I; 1275 Function *DF = cast<Function>(ValueMap[SF]); 1276 1277 if (!DF->use_empty()) { 1278 1279 // Materialize if necessary. 1280 if (SF->isDeclaration()) { 1281 if (!SF->isMaterializable()) 1282 continue; 1283 if (SF->Materialize(&ErrorMsg)) 1284 return true; 1285 } 1286 1287 // Link in function body. 1288 linkFunctionBody(DF, SF); 1289 SF->Dematerialize(); 1290 1291 // "Remove" from vector by setting the element to 0. 1292 *I = 0; 1293 1294 // Set flag to indicate we may have more functions to lazily link in 1295 // since we linked in a function. 1296 LinkedInAnyFunctions = true; 1297 } 1298 } 1299 } while (LinkedInAnyFunctions); 1300 1301 // Remove any prototypes of functions that were not actually linked in. 1302 for(std::vector<Function*>::iterator I = LazilyLinkFunctions.begin(), 1303 E = LazilyLinkFunctions.end(); I != E; ++I) { 1304 if (!*I) 1305 continue; 1306 1307 Function *SF = *I; 1308 Function *DF = cast<Function>(ValueMap[SF]); 1309 if (DF->use_empty()) 1310 DF->eraseFromParent(); 1311 } 1312 1313 // Now that all of the types from the source are used, resolve any structs 1314 // copied over to the dest that didn't exist there. 1315 TypeMap.linkDefinedTypeBodies(); 1316 1317 return false; 1318} 1319 1320//===----------------------------------------------------------------------===// 1321// LinkModules entrypoint. 1322//===----------------------------------------------------------------------===// 1323 1324/// LinkModules - This function links two modules together, with the resulting 1325/// left module modified to be the composite of the two input modules. If an 1326/// error occurs, true is returned and ErrorMsg (if not null) is set to indicate 1327/// the problem. Upon failure, the Dest module could be in a modified state, 1328/// and shouldn't be relied on to be consistent. 1329bool Linker::LinkModules(Module *Dest, Module *Src, unsigned Mode, 1330 std::string *ErrorMsg) { 1331 ModuleLinker TheLinker(Dest, Src, Mode); 1332 if (TheLinker.run()) { 1333 if (ErrorMsg) *ErrorMsg = TheLinker.ErrorMsg; 1334 return true; 1335 } 1336 1337 return false; 1338} 1339 1340//===----------------------------------------------------------------------===// 1341// C API. 1342//===----------------------------------------------------------------------===// 1343 1344LLVMBool LLVMLinkModules(LLVMModuleRef Dest, LLVMModuleRef Src, 1345 LLVMLinkerMode Mode, char **OutMessages) { 1346 std::string Messages; 1347 LLVMBool Result = Linker::LinkModules(unwrap(Dest), unwrap(Src), 1348 Mode, OutMessages? &Messages : 0); 1349 if (OutMessages) 1350 *OutMessages = strdup(Messages.c_str()); 1351 return Result; 1352} 1353