LinkModules.cpp revision 36b56886974eae4f9c5ebc96befd3e7bfe5de338
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/Linker.h" 15#include "llvm-c/Linker.h" 16#include "llvm/ADT/Optional.h" 17#include "llvm/ADT/SetVector.h" 18#include "llvm/ADT/SmallString.h" 19#include "llvm/IR/Constants.h" 20#include "llvm/IR/Module.h" 21#include "llvm/IR/TypeFinder.h" 22#include "llvm/Support/CommandLine.h" 23#include "llvm/Support/Debug.h" 24#include "llvm/Support/raw_ostream.h" 25#include "llvm/Transforms/Utils/Cloning.h" 26#include <cctype> 27using namespace llvm; 28 29 30//===----------------------------------------------------------------------===// 31// TypeMap implementation. 32//===----------------------------------------------------------------------===// 33 34namespace { 35 typedef SmallPtrSet<StructType*, 32> TypeSet; 36 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 TypeMapTy(TypeSet &Set) : DstStructTypesSet(Set) {} 58 59 TypeSet &DstStructTypesSet; 60 /// addTypeMapping - Indicate that the specified type in the destination 61 /// module is conceptually equivalent to the specified type in the source 62 /// module. 63 void addTypeMapping(Type *DstTy, Type *SrcTy); 64 65 /// linkDefinedTypeBodies - Produce a body for an opaque type in the dest 66 /// module from a type definition in the source module. 67 void linkDefinedTypeBodies(); 68 69 /// get - Return the mapped type to use for the specified input type from the 70 /// source module. 71 Type *get(Type *SrcTy); 72 73 FunctionType *get(FunctionType *T) {return cast<FunctionType>(get((Type*)T));} 74 75 /// dump - Dump out the type map for debugging purposes. 76 void dump() const { 77 for (DenseMap<Type*, Type*>::const_iterator 78 I = MappedTypes.begin(), E = MappedTypes.end(); I != E; ++I) { 79 dbgs() << "TypeMap: "; 80 I->first->dump(); 81 dbgs() << " => "; 82 I->second->dump(); 83 dbgs() << '\n'; 84 } 85 } 86 87private: 88 Type *getImpl(Type *T); 89 /// remapType - Implement the ValueMapTypeRemapper interface. 90 Type *remapType(Type *SrcTy) override { 91 return get(SrcTy); 92 } 93 94 bool areTypesIsomorphic(Type *DstTy, Type *SrcTy); 95}; 96} 97 98void TypeMapTy::addTypeMapping(Type *DstTy, Type *SrcTy) { 99 Type *&Entry = MappedTypes[SrcTy]; 100 if (Entry) return; 101 102 if (DstTy == SrcTy) { 103 Entry = DstTy; 104 return; 105 } 106 107 // Check to see if these types are recursively isomorphic and establish a 108 // mapping between them if so. 109 if (!areTypesIsomorphic(DstTy, SrcTy)) { 110 // Oops, they aren't isomorphic. Just discard this request by rolling out 111 // any speculative mappings we've established. 112 for (unsigned i = 0, e = SpeculativeTypes.size(); i != e; ++i) 113 MappedTypes.erase(SpeculativeTypes[i]); 114 } 115 SpeculativeTypes.clear(); 116} 117 118/// areTypesIsomorphic - Recursively walk this pair of types, returning true 119/// if they are isomorphic, false if they are not. 120bool TypeMapTy::areTypesIsomorphic(Type *DstTy, Type *SrcTy) { 121 // Two types with differing kinds are clearly not isomorphic. 122 if (DstTy->getTypeID() != SrcTy->getTypeID()) return false; 123 124 // If we have an entry in the MappedTypes table, then we have our answer. 125 Type *&Entry = MappedTypes[SrcTy]; 126 if (Entry) 127 return Entry == DstTy; 128 129 // Two identical types are clearly isomorphic. Remember this 130 // non-speculatively. 131 if (DstTy == SrcTy) { 132 Entry = DstTy; 133 return true; 134 } 135 136 // Okay, we have two types with identical kinds that we haven't seen before. 137 138 // If this is an opaque struct type, special case it. 139 if (StructType *SSTy = dyn_cast<StructType>(SrcTy)) { 140 // Mapping an opaque type to any struct, just keep the dest struct. 141 if (SSTy->isOpaque()) { 142 Entry = DstTy; 143 SpeculativeTypes.push_back(SrcTy); 144 return true; 145 } 146 147 // Mapping a non-opaque source type to an opaque dest. If this is the first 148 // type that we're mapping onto this destination type then we succeed. Keep 149 // the dest, but fill it in later. This doesn't need to be speculative. If 150 // this is the second (different) type that we're trying to map onto the 151 // same opaque type then we fail. 152 if (cast<StructType>(DstTy)->isOpaque()) { 153 // We can only map one source type onto the opaque destination type. 154 if (!DstResolvedOpaqueTypes.insert(cast<StructType>(DstTy))) 155 return false; 156 SrcDefinitionsToResolve.push_back(SSTy); 157 Entry = DstTy; 158 return true; 159 } 160 } 161 162 // If the number of subtypes disagree between the two types, then we fail. 163 if (SrcTy->getNumContainedTypes() != DstTy->getNumContainedTypes()) 164 return false; 165 166 // Fail if any of the extra properties (e.g. array size) of the type disagree. 167 if (isa<IntegerType>(DstTy)) 168 return false; // bitwidth disagrees. 169 if (PointerType *PT = dyn_cast<PointerType>(DstTy)) { 170 if (PT->getAddressSpace() != cast<PointerType>(SrcTy)->getAddressSpace()) 171 return false; 172 173 } else if (FunctionType *FT = dyn_cast<FunctionType>(DstTy)) { 174 if (FT->isVarArg() != cast<FunctionType>(SrcTy)->isVarArg()) 175 return false; 176 } else if (StructType *DSTy = dyn_cast<StructType>(DstTy)) { 177 StructType *SSTy = cast<StructType>(SrcTy); 178 if (DSTy->isLiteral() != SSTy->isLiteral() || 179 DSTy->isPacked() != SSTy->isPacked()) 180 return false; 181 } else if (ArrayType *DATy = dyn_cast<ArrayType>(DstTy)) { 182 if (DATy->getNumElements() != cast<ArrayType>(SrcTy)->getNumElements()) 183 return false; 184 } else if (VectorType *DVTy = dyn_cast<VectorType>(DstTy)) { 185 if (DVTy->getNumElements() != cast<VectorType>(SrcTy)->getNumElements()) 186 return false; 187 } 188 189 // Otherwise, we speculate that these two types will line up and recursively 190 // check the subelements. 191 Entry = DstTy; 192 SpeculativeTypes.push_back(SrcTy); 193 194 for (unsigned i = 0, e = SrcTy->getNumContainedTypes(); i != e; ++i) 195 if (!areTypesIsomorphic(DstTy->getContainedType(i), 196 SrcTy->getContainedType(i))) 197 return false; 198 199 // If everything seems to have lined up, then everything is great. 200 return true; 201} 202 203/// linkDefinedTypeBodies - Produce a body for an opaque type in the dest 204/// module from a type definition in the source module. 205void TypeMapTy::linkDefinedTypeBodies() { 206 SmallVector<Type*, 16> Elements; 207 SmallString<16> TmpName; 208 209 // Note that processing entries in this loop (calling 'get') can add new 210 // entries to the SrcDefinitionsToResolve vector. 211 while (!SrcDefinitionsToResolve.empty()) { 212 StructType *SrcSTy = SrcDefinitionsToResolve.pop_back_val(); 213 StructType *DstSTy = cast<StructType>(MappedTypes[SrcSTy]); 214 215 // TypeMap is a many-to-one mapping, if there were multiple types that 216 // provide a body for DstSTy then previous iterations of this loop may have 217 // already handled it. Just ignore this case. 218 if (!DstSTy->isOpaque()) continue; 219 assert(!SrcSTy->isOpaque() && "Not resolving a definition?"); 220 221 // Map the body of the source type over to a new body for the dest type. 222 Elements.resize(SrcSTy->getNumElements()); 223 for (unsigned i = 0, e = Elements.size(); i != e; ++i) 224 Elements[i] = getImpl(SrcSTy->getElementType(i)); 225 226 DstSTy->setBody(Elements, SrcSTy->isPacked()); 227 228 // If DstSTy has no name or has a longer name than STy, then viciously steal 229 // STy's name. 230 if (!SrcSTy->hasName()) continue; 231 StringRef SrcName = SrcSTy->getName(); 232 233 if (!DstSTy->hasName() || DstSTy->getName().size() > SrcName.size()) { 234 TmpName.insert(TmpName.end(), SrcName.begin(), SrcName.end()); 235 SrcSTy->setName(""); 236 DstSTy->setName(TmpName.str()); 237 TmpName.clear(); 238 } 239 } 240 241 DstResolvedOpaqueTypes.clear(); 242} 243 244/// get - Return the mapped type to use for the specified input type from the 245/// source module. 246Type *TypeMapTy::get(Type *Ty) { 247 Type *Result = getImpl(Ty); 248 249 // If this caused a reference to any struct type, resolve it before returning. 250 if (!SrcDefinitionsToResolve.empty()) 251 linkDefinedTypeBodies(); 252 return Result; 253} 254 255/// getImpl - This is the recursive version of get(). 256Type *TypeMapTy::getImpl(Type *Ty) { 257 // If we already have an entry for this type, return it. 258 Type **Entry = &MappedTypes[Ty]; 259 if (*Entry) return *Entry; 260 261 // If this is not a named struct type, then just map all of the elements and 262 // then rebuild the type from inside out. 263 if (!isa<StructType>(Ty) || cast<StructType>(Ty)->isLiteral()) { 264 // If there are no element types to map, then the type is itself. This is 265 // true for the anonymous {} struct, things like 'float', integers, etc. 266 if (Ty->getNumContainedTypes() == 0) 267 return *Entry = Ty; 268 269 // Remap all of the elements, keeping track of whether any of them change. 270 bool AnyChange = false; 271 SmallVector<Type*, 4> ElementTypes; 272 ElementTypes.resize(Ty->getNumContainedTypes()); 273 for (unsigned i = 0, e = Ty->getNumContainedTypes(); i != e; ++i) { 274 ElementTypes[i] = getImpl(Ty->getContainedType(i)); 275 AnyChange |= ElementTypes[i] != Ty->getContainedType(i); 276 } 277 278 // If we found our type while recursively processing stuff, just use it. 279 Entry = &MappedTypes[Ty]; 280 if (*Entry) return *Entry; 281 282 // If all of the element types mapped directly over, then the type is usable 283 // as-is. 284 if (!AnyChange) 285 return *Entry = Ty; 286 287 // Otherwise, rebuild a modified type. 288 switch (Ty->getTypeID()) { 289 default: llvm_unreachable("unknown derived type to remap"); 290 case Type::ArrayTyID: 291 return *Entry = ArrayType::get(ElementTypes[0], 292 cast<ArrayType>(Ty)->getNumElements()); 293 case Type::VectorTyID: 294 return *Entry = VectorType::get(ElementTypes[0], 295 cast<VectorType>(Ty)->getNumElements()); 296 case Type::PointerTyID: 297 return *Entry = PointerType::get(ElementTypes[0], 298 cast<PointerType>(Ty)->getAddressSpace()); 299 case Type::FunctionTyID: 300 return *Entry = FunctionType::get(ElementTypes[0], 301 makeArrayRef(ElementTypes).slice(1), 302 cast<FunctionType>(Ty)->isVarArg()); 303 case Type::StructTyID: 304 // Note that this is only reached for anonymous structs. 305 return *Entry = StructType::get(Ty->getContext(), ElementTypes, 306 cast<StructType>(Ty)->isPacked()); 307 } 308 } 309 310 // Otherwise, this is an unmapped named struct. If the struct can be directly 311 // mapped over, just use it as-is. This happens in a case when the linked-in 312 // module has something like: 313 // %T = type {%T*, i32} 314 // @GV = global %T* null 315 // where T does not exist at all in the destination module. 316 // 317 // The other case we watch for is when the type is not in the destination 318 // module, but that it has to be rebuilt because it refers to something that 319 // is already mapped. For example, if the destination module has: 320 // %A = type { i32 } 321 // and the source module has something like 322 // %A' = type { i32 } 323 // %B = type { %A'* } 324 // @GV = global %B* null 325 // then we want to create a new type: "%B = type { %A*}" and have it take the 326 // pristine "%B" name from the source module. 327 // 328 // To determine which case this is, we have to recursively walk the type graph 329 // speculating that we'll be able to reuse it unmodified. Only if this is 330 // safe would we map the entire thing over. Because this is an optimization, 331 // and is not required for the prettiness of the linked module, we just skip 332 // it and always rebuild a type here. 333 StructType *STy = cast<StructType>(Ty); 334 335 // If the type is opaque, we can just use it directly. 336 if (STy->isOpaque()) { 337 // A named structure type from src module is used. Add it to the Set of 338 // identified structs in the destination module. 339 DstStructTypesSet.insert(STy); 340 return *Entry = STy; 341 } 342 343 // Otherwise we create a new type and resolve its body later. This will be 344 // resolved by the top level of get(). 345 SrcDefinitionsToResolve.push_back(STy); 346 StructType *DTy = StructType::create(STy->getContext()); 347 // A new identified structure type was created. Add it to the set of 348 // identified structs in the destination module. 349 DstStructTypesSet.insert(DTy); 350 DstResolvedOpaqueTypes.insert(DTy); 351 return *Entry = DTy; 352} 353 354//===----------------------------------------------------------------------===// 355// ModuleLinker implementation. 356//===----------------------------------------------------------------------===// 357 358namespace { 359 class ModuleLinker; 360 361 /// ValueMaterializerTy - Creates prototypes for functions that are lazily 362 /// linked on the fly. This speeds up linking for modules with many 363 /// lazily linked functions of which few get used. 364 class ValueMaterializerTy : public ValueMaterializer { 365 TypeMapTy &TypeMap; 366 Module *DstM; 367 std::vector<Function*> &LazilyLinkFunctions; 368 public: 369 ValueMaterializerTy(TypeMapTy &TypeMap, Module *DstM, 370 std::vector<Function*> &LazilyLinkFunctions) : 371 ValueMaterializer(), TypeMap(TypeMap), DstM(DstM), 372 LazilyLinkFunctions(LazilyLinkFunctions) { 373 } 374 375 Value *materializeValueFor(Value *V) override; 376 }; 377 378 /// ModuleLinker - This is an implementation class for the LinkModules 379 /// function, which is the entrypoint for this file. 380 class ModuleLinker { 381 Module *DstM, *SrcM; 382 383 TypeMapTy TypeMap; 384 ValueMaterializerTy ValMaterializer; 385 386 /// ValueMap - Mapping of values from what they used to be in Src, to what 387 /// they are now in DstM. ValueToValueMapTy is a ValueMap, which involves 388 /// some overhead due to the use of Value handles which the Linker doesn't 389 /// actually need, but this allows us to reuse the ValueMapper code. 390 ValueToValueMapTy ValueMap; 391 392 struct AppendingVarInfo { 393 GlobalVariable *NewGV; // New aggregate global in dest module. 394 Constant *DstInit; // Old initializer from dest module. 395 Constant *SrcInit; // Old initializer from src module. 396 }; 397 398 std::vector<AppendingVarInfo> AppendingVars; 399 400 unsigned Mode; // Mode to treat source module. 401 402 // Set of items not to link in from source. 403 SmallPtrSet<const Value*, 16> DoNotLinkFromSource; 404 405 // Vector of functions to lazily link in. 406 std::vector<Function*> LazilyLinkFunctions; 407 408 bool SuppressWarnings; 409 410 public: 411 std::string ErrorMsg; 412 413 ModuleLinker(Module *dstM, TypeSet &Set, Module *srcM, unsigned mode, 414 bool SuppressWarnings=false) 415 : DstM(dstM), SrcM(srcM), TypeMap(Set), 416 ValMaterializer(TypeMap, DstM, LazilyLinkFunctions), Mode(mode), 417 SuppressWarnings(SuppressWarnings) {} 418 419 bool run(); 420 421 private: 422 /// emitError - Helper method for setting a message and returning an error 423 /// code. 424 bool emitError(const Twine &Message) { 425 ErrorMsg = Message.str(); 426 return true; 427 } 428 429 /// getLinkageResult - This analyzes the two global values and determines 430 /// what the result will look like in the destination module. 431 bool getLinkageResult(GlobalValue *Dest, const GlobalValue *Src, 432 GlobalValue::LinkageTypes <, 433 GlobalValue::VisibilityTypes &Vis, 434 bool &LinkFromSrc); 435 436 /// getLinkedToGlobal - Given a global in the source module, return the 437 /// global in the destination module that is being linked to, if any. 438 GlobalValue *getLinkedToGlobal(GlobalValue *SrcGV) { 439 // If the source has no name it can't link. If it has local linkage, 440 // there is no name match-up going on. 441 if (!SrcGV->hasName() || SrcGV->hasLocalLinkage()) 442 return 0; 443 444 // Otherwise see if we have a match in the destination module's symtab. 445 GlobalValue *DGV = DstM->getNamedValue(SrcGV->getName()); 446 if (DGV == 0) return 0; 447 448 // If we found a global with the same name in the dest module, but it has 449 // internal linkage, we are really not doing any linkage here. 450 if (DGV->hasLocalLinkage()) 451 return 0; 452 453 // Otherwise, we do in fact link to the destination global. 454 return DGV; 455 } 456 457 void computeTypeMapping(); 458 459 bool linkAppendingVarProto(GlobalVariable *DstGV, GlobalVariable *SrcGV); 460 bool linkGlobalProto(GlobalVariable *SrcGV); 461 bool linkFunctionProto(Function *SrcF); 462 bool linkAliasProto(GlobalAlias *SrcA); 463 bool linkModuleFlagsMetadata(); 464 465 void linkAppendingVarInit(const AppendingVarInfo &AVI); 466 void linkGlobalInits(); 467 void linkFunctionBody(Function *Dst, Function *Src); 468 void linkAliasBodies(); 469 void linkNamedMDNodes(); 470 }; 471} 472 473/// forceRenaming - The LLVM SymbolTable class autorenames globals that conflict 474/// in the symbol table. This is good for all clients except for us. Go 475/// through the trouble to force this back. 476static void forceRenaming(GlobalValue *GV, StringRef Name) { 477 // If the global doesn't force its name or if it already has the right name, 478 // there is nothing for us to do. 479 if (GV->hasLocalLinkage() || GV->getName() == Name) 480 return; 481 482 Module *M = GV->getParent(); 483 484 // If there is a conflict, rename the conflict. 485 if (GlobalValue *ConflictGV = M->getNamedValue(Name)) { 486 GV->takeName(ConflictGV); 487 ConflictGV->setName(Name); // This will cause ConflictGV to get renamed 488 assert(ConflictGV->getName() != Name && "forceRenaming didn't work"); 489 } else { 490 GV->setName(Name); // Force the name back 491 } 492} 493 494/// copyGVAttributes - copy additional attributes (those not needed to construct 495/// a GlobalValue) from the SrcGV to the DestGV. 496static void copyGVAttributes(GlobalValue *DestGV, const GlobalValue *SrcGV) { 497 // Use the maximum alignment, rather than just copying the alignment of SrcGV. 498 unsigned Alignment = std::max(DestGV->getAlignment(), SrcGV->getAlignment()); 499 DestGV->copyAttributesFrom(SrcGV); 500 DestGV->setAlignment(Alignment); 501 502 forceRenaming(DestGV, SrcGV->getName()); 503} 504 505static bool isLessConstraining(GlobalValue::VisibilityTypes a, 506 GlobalValue::VisibilityTypes b) { 507 if (a == GlobalValue::HiddenVisibility) 508 return false; 509 if (b == GlobalValue::HiddenVisibility) 510 return true; 511 if (a == GlobalValue::ProtectedVisibility) 512 return false; 513 if (b == GlobalValue::ProtectedVisibility) 514 return true; 515 return false; 516} 517 518Value *ValueMaterializerTy::materializeValueFor(Value *V) { 519 Function *SF = dyn_cast<Function>(V); 520 if (!SF) 521 return NULL; 522 523 Function *DF = Function::Create(TypeMap.get(SF->getFunctionType()), 524 SF->getLinkage(), SF->getName(), DstM); 525 copyGVAttributes(DF, SF); 526 527 LazilyLinkFunctions.push_back(SF); 528 return DF; 529} 530 531 532/// getLinkageResult - This analyzes the two global values and determines what 533/// the result will look like in the destination module. In particular, it 534/// computes the resultant linkage type and visibility, computes whether the 535/// global in the source should be copied over to the destination (replacing 536/// the existing one), and computes whether this linkage is an error or not. 537bool ModuleLinker::getLinkageResult(GlobalValue *Dest, const GlobalValue *Src, 538 GlobalValue::LinkageTypes <, 539 GlobalValue::VisibilityTypes &Vis, 540 bool &LinkFromSrc) { 541 assert(Dest && "Must have two globals being queried"); 542 assert(!Src->hasLocalLinkage() && 543 "If Src has internal linkage, Dest shouldn't be set!"); 544 545 bool SrcIsDeclaration = Src->isDeclaration() && !Src->isMaterializable(); 546 bool DestIsDeclaration = Dest->isDeclaration(); 547 548 if (SrcIsDeclaration) { 549 // If Src is external or if both Src & Dest are external.. Just link the 550 // external globals, we aren't adding anything. 551 if (Src->hasDLLImportStorageClass()) { 552 // If one of GVs is marked as DLLImport, result should be dllimport'ed. 553 if (DestIsDeclaration) { 554 LinkFromSrc = true; 555 LT = Src->getLinkage(); 556 } 557 } else if (Dest->hasExternalWeakLinkage()) { 558 // If the Dest is weak, use the source linkage. 559 LinkFromSrc = true; 560 LT = Src->getLinkage(); 561 } else { 562 LinkFromSrc = false; 563 LT = Dest->getLinkage(); 564 } 565 } else if (DestIsDeclaration && !Dest->hasDLLImportStorageClass()) { 566 // If Dest is external but Src is not: 567 LinkFromSrc = true; 568 LT = Src->getLinkage(); 569 } else if (Src->isWeakForLinker()) { 570 // At this point we know that Dest has LinkOnce, External*, Weak, Common, 571 // or DLL* linkage. 572 if (Dest->hasExternalWeakLinkage() || 573 Dest->hasAvailableExternallyLinkage() || 574 (Dest->hasLinkOnceLinkage() && 575 (Src->hasWeakLinkage() || Src->hasCommonLinkage()))) { 576 LinkFromSrc = true; 577 LT = Src->getLinkage(); 578 } else { 579 LinkFromSrc = false; 580 LT = Dest->getLinkage(); 581 } 582 } else if (Dest->isWeakForLinker()) { 583 // At this point we know that Src has External* or DLL* linkage. 584 if (Src->hasExternalWeakLinkage()) { 585 LinkFromSrc = false; 586 LT = Dest->getLinkage(); 587 } else { 588 LinkFromSrc = true; 589 LT = GlobalValue::ExternalLinkage; 590 } 591 } else { 592 assert((Dest->hasExternalLinkage() || Dest->hasExternalWeakLinkage()) && 593 (Src->hasExternalLinkage() || Src->hasExternalWeakLinkage()) && 594 "Unexpected linkage type!"); 595 return emitError("Linking globals named '" + Src->getName() + 596 "': symbol multiply defined!"); 597 } 598 599 // Compute the visibility. We follow the rules in the System V Application 600 // Binary Interface. 601 Vis = isLessConstraining(Src->getVisibility(), Dest->getVisibility()) ? 602 Dest->getVisibility() : Src->getVisibility(); 603 return false; 604} 605 606/// computeTypeMapping - Loop over all of the linked values to compute type 607/// mappings. For example, if we link "extern Foo *x" and "Foo *x = NULL", then 608/// we have two struct types 'Foo' but one got renamed when the module was 609/// loaded into the same LLVMContext. 610void ModuleLinker::computeTypeMapping() { 611 // Incorporate globals. 612 for (Module::global_iterator I = SrcM->global_begin(), 613 E = SrcM->global_end(); I != E; ++I) { 614 GlobalValue *DGV = getLinkedToGlobal(I); 615 if (DGV == 0) continue; 616 617 if (!DGV->hasAppendingLinkage() || !I->hasAppendingLinkage()) { 618 TypeMap.addTypeMapping(DGV->getType(), I->getType()); 619 continue; 620 } 621 622 // Unify the element type of appending arrays. 623 ArrayType *DAT = cast<ArrayType>(DGV->getType()->getElementType()); 624 ArrayType *SAT = cast<ArrayType>(I->getType()->getElementType()); 625 TypeMap.addTypeMapping(DAT->getElementType(), SAT->getElementType()); 626 } 627 628 // Incorporate functions. 629 for (Module::iterator I = SrcM->begin(), E = SrcM->end(); I != E; ++I) { 630 if (GlobalValue *DGV = getLinkedToGlobal(I)) 631 TypeMap.addTypeMapping(DGV->getType(), I->getType()); 632 } 633 634 // Incorporate types by name, scanning all the types in the source module. 635 // At this point, the destination module may have a type "%foo = { i32 }" for 636 // example. When the source module got loaded into the same LLVMContext, if 637 // it had the same type, it would have been renamed to "%foo.42 = { i32 }". 638 TypeFinder SrcStructTypes; 639 SrcStructTypes.run(*SrcM, true); 640 SmallPtrSet<StructType*, 32> SrcStructTypesSet(SrcStructTypes.begin(), 641 SrcStructTypes.end()); 642 643 for (unsigned i = 0, e = SrcStructTypes.size(); i != e; ++i) { 644 StructType *ST = SrcStructTypes[i]; 645 if (!ST->hasName()) continue; 646 647 // Check to see if there is a dot in the name followed by a digit. 648 size_t DotPos = ST->getName().rfind('.'); 649 if (DotPos == 0 || DotPos == StringRef::npos || 650 ST->getName().back() == '.' || 651 !isdigit(static_cast<unsigned char>(ST->getName()[DotPos+1]))) 652 continue; 653 654 // Check to see if the destination module has a struct with the prefix name. 655 if (StructType *DST = DstM->getTypeByName(ST->getName().substr(0, DotPos))) 656 // Don't use it if this actually came from the source module. They're in 657 // the same LLVMContext after all. Also don't use it unless the type is 658 // actually used in the destination module. This can happen in situations 659 // like this: 660 // 661 // Module A Module B 662 // -------- -------- 663 // %Z = type { %A } %B = type { %C.1 } 664 // %A = type { %B.1, [7 x i8] } %C.1 = type { i8* } 665 // %B.1 = type { %C } %A.2 = type { %B.3, [5 x i8] } 666 // %C = type { i8* } %B.3 = type { %C.1 } 667 // 668 // When we link Module B with Module A, the '%B' in Module B is 669 // used. However, that would then use '%C.1'. But when we process '%C.1', 670 // we prefer to take the '%C' version. So we are then left with both 671 // '%C.1' and '%C' being used for the same types. This leads to some 672 // variables using one type and some using the other. 673 if (!SrcStructTypesSet.count(DST) && TypeMap.DstStructTypesSet.count(DST)) 674 TypeMap.addTypeMapping(DST, ST); 675 } 676 677 // Don't bother incorporating aliases, they aren't generally typed well. 678 679 // Now that we have discovered all of the type equivalences, get a body for 680 // any 'opaque' types in the dest module that are now resolved. 681 TypeMap.linkDefinedTypeBodies(); 682} 683 684/// linkAppendingVarProto - If there were any appending global variables, link 685/// them together now. Return true on error. 686bool ModuleLinker::linkAppendingVarProto(GlobalVariable *DstGV, 687 GlobalVariable *SrcGV) { 688 689 if (!SrcGV->hasAppendingLinkage() || !DstGV->hasAppendingLinkage()) 690 return emitError("Linking globals named '" + SrcGV->getName() + 691 "': can only link appending global with another appending global!"); 692 693 ArrayType *DstTy = cast<ArrayType>(DstGV->getType()->getElementType()); 694 ArrayType *SrcTy = 695 cast<ArrayType>(TypeMap.get(SrcGV->getType()->getElementType())); 696 Type *EltTy = DstTy->getElementType(); 697 698 // Check to see that they two arrays agree on type. 699 if (EltTy != SrcTy->getElementType()) 700 return emitError("Appending variables with different element types!"); 701 if (DstGV->isConstant() != SrcGV->isConstant()) 702 return emitError("Appending variables linked with different const'ness!"); 703 704 if (DstGV->getAlignment() != SrcGV->getAlignment()) 705 return emitError( 706 "Appending variables with different alignment need to be linked!"); 707 708 if (DstGV->getVisibility() != SrcGV->getVisibility()) 709 return emitError( 710 "Appending variables with different visibility need to be linked!"); 711 712 if (DstGV->hasUnnamedAddr() != SrcGV->hasUnnamedAddr()) 713 return emitError( 714 "Appending variables with different unnamed_addr need to be linked!"); 715 716 if (DstGV->getSection() != SrcGV->getSection()) 717 return emitError( 718 "Appending variables with different section name need to be linked!"); 719 720 uint64_t NewSize = DstTy->getNumElements() + SrcTy->getNumElements(); 721 ArrayType *NewType = ArrayType::get(EltTy, NewSize); 722 723 // Create the new global variable. 724 GlobalVariable *NG = 725 new GlobalVariable(*DstGV->getParent(), NewType, SrcGV->isConstant(), 726 DstGV->getLinkage(), /*init*/0, /*name*/"", DstGV, 727 DstGV->getThreadLocalMode(), 728 DstGV->getType()->getAddressSpace()); 729 730 // Propagate alignment, visibility and section info. 731 copyGVAttributes(NG, DstGV); 732 733 AppendingVarInfo AVI; 734 AVI.NewGV = NG; 735 AVI.DstInit = DstGV->getInitializer(); 736 AVI.SrcInit = SrcGV->getInitializer(); 737 AppendingVars.push_back(AVI); 738 739 // Replace any uses of the two global variables with uses of the new 740 // global. 741 ValueMap[SrcGV] = ConstantExpr::getBitCast(NG, TypeMap.get(SrcGV->getType())); 742 743 DstGV->replaceAllUsesWith(ConstantExpr::getBitCast(NG, DstGV->getType())); 744 DstGV->eraseFromParent(); 745 746 // Track the source variable so we don't try to link it. 747 DoNotLinkFromSource.insert(SrcGV); 748 749 return false; 750} 751 752/// linkGlobalProto - Loop through the global variables in the src module and 753/// merge them into the dest module. 754bool ModuleLinker::linkGlobalProto(GlobalVariable *SGV) { 755 GlobalValue *DGV = getLinkedToGlobal(SGV); 756 llvm::Optional<GlobalValue::VisibilityTypes> NewVisibility; 757 bool HasUnnamedAddr = SGV->hasUnnamedAddr(); 758 759 if (DGV) { 760 // Concatenation of appending linkage variables is magic and handled later. 761 if (DGV->hasAppendingLinkage() || SGV->hasAppendingLinkage()) 762 return linkAppendingVarProto(cast<GlobalVariable>(DGV), SGV); 763 764 // Determine whether linkage of these two globals follows the source 765 // module's definition or the destination module's definition. 766 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; 767 GlobalValue::VisibilityTypes NV; 768 bool LinkFromSrc = false; 769 if (getLinkageResult(DGV, SGV, NewLinkage, NV, LinkFromSrc)) 770 return true; 771 NewVisibility = NV; 772 HasUnnamedAddr = HasUnnamedAddr && DGV->hasUnnamedAddr(); 773 774 // If we're not linking from the source, then keep the definition that we 775 // have. 776 if (!LinkFromSrc) { 777 // Special case for const propagation. 778 if (GlobalVariable *DGVar = dyn_cast<GlobalVariable>(DGV)) 779 if (DGVar->isDeclaration() && SGV->isConstant() && !DGVar->isConstant()) 780 DGVar->setConstant(true); 781 782 // Set calculated linkage, visibility and unnamed_addr. 783 DGV->setLinkage(NewLinkage); 784 DGV->setVisibility(*NewVisibility); 785 DGV->setUnnamedAddr(HasUnnamedAddr); 786 787 // Make sure to remember this mapping. 788 ValueMap[SGV] = ConstantExpr::getBitCast(DGV,TypeMap.get(SGV->getType())); 789 790 // Track the source global so that we don't attempt to copy it over when 791 // processing global initializers. 792 DoNotLinkFromSource.insert(SGV); 793 794 return false; 795 } 796 } 797 798 // No linking to be performed or linking from the source: simply create an 799 // identical version of the symbol over in the dest module... the 800 // initializer will be filled in later by LinkGlobalInits. 801 GlobalVariable *NewDGV = 802 new GlobalVariable(*DstM, TypeMap.get(SGV->getType()->getElementType()), 803 SGV->isConstant(), SGV->getLinkage(), /*init*/0, 804 SGV->getName(), /*insertbefore*/0, 805 SGV->getThreadLocalMode(), 806 SGV->getType()->getAddressSpace()); 807 // Propagate alignment, visibility and section info. 808 copyGVAttributes(NewDGV, SGV); 809 if (NewVisibility) 810 NewDGV->setVisibility(*NewVisibility); 811 NewDGV->setUnnamedAddr(HasUnnamedAddr); 812 813 if (DGV) { 814 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDGV, DGV->getType())); 815 DGV->eraseFromParent(); 816 } 817 818 // Make sure to remember this mapping. 819 ValueMap[SGV] = NewDGV; 820 return false; 821} 822 823/// linkFunctionProto - Link the function in the source module into the 824/// destination module if needed, setting up mapping information. 825bool ModuleLinker::linkFunctionProto(Function *SF) { 826 GlobalValue *DGV = getLinkedToGlobal(SF); 827 llvm::Optional<GlobalValue::VisibilityTypes> NewVisibility; 828 bool HasUnnamedAddr = SF->hasUnnamedAddr(); 829 830 if (DGV) { 831 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; 832 bool LinkFromSrc = false; 833 GlobalValue::VisibilityTypes NV; 834 if (getLinkageResult(DGV, SF, NewLinkage, NV, LinkFromSrc)) 835 return true; 836 NewVisibility = NV; 837 HasUnnamedAddr = HasUnnamedAddr && DGV->hasUnnamedAddr(); 838 839 if (!LinkFromSrc) { 840 // Set calculated linkage 841 DGV->setLinkage(NewLinkage); 842 DGV->setVisibility(*NewVisibility); 843 DGV->setUnnamedAddr(HasUnnamedAddr); 844 845 // Make sure to remember this mapping. 846 ValueMap[SF] = ConstantExpr::getBitCast(DGV, TypeMap.get(SF->getType())); 847 848 // Track the function from the source module so we don't attempt to remap 849 // it. 850 DoNotLinkFromSource.insert(SF); 851 852 return false; 853 } 854 } 855 856 // If the function is to be lazily linked, don't create it just yet. 857 // The ValueMaterializerTy will deal with creating it if it's used. 858 if (!DGV && (SF->hasLocalLinkage() || SF->hasLinkOnceLinkage() || 859 SF->hasAvailableExternallyLinkage())) { 860 DoNotLinkFromSource.insert(SF); 861 return false; 862 } 863 864 // If there is no linkage to be performed or we are linking from the source, 865 // bring SF over. 866 Function *NewDF = Function::Create(TypeMap.get(SF->getFunctionType()), 867 SF->getLinkage(), SF->getName(), DstM); 868 copyGVAttributes(NewDF, SF); 869 if (NewVisibility) 870 NewDF->setVisibility(*NewVisibility); 871 NewDF->setUnnamedAddr(HasUnnamedAddr); 872 873 if (DGV) { 874 // Any uses of DF need to change to NewDF, with cast. 875 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDF, DGV->getType())); 876 DGV->eraseFromParent(); 877 } 878 879 ValueMap[SF] = NewDF; 880 return false; 881} 882 883/// LinkAliasProto - Set up prototypes for any aliases that come over from the 884/// source module. 885bool ModuleLinker::linkAliasProto(GlobalAlias *SGA) { 886 GlobalValue *DGV = getLinkedToGlobal(SGA); 887 llvm::Optional<GlobalValue::VisibilityTypes> NewVisibility; 888 889 if (DGV) { 890 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; 891 GlobalValue::VisibilityTypes NV; 892 bool LinkFromSrc = false; 893 if (getLinkageResult(DGV, SGA, NewLinkage, NV, LinkFromSrc)) 894 return true; 895 NewVisibility = NV; 896 897 if (!LinkFromSrc) { 898 // Set calculated linkage. 899 DGV->setLinkage(NewLinkage); 900 DGV->setVisibility(*NewVisibility); 901 902 // Make sure to remember this mapping. 903 ValueMap[SGA] = ConstantExpr::getBitCast(DGV,TypeMap.get(SGA->getType())); 904 905 // Track the alias from the source module so we don't attempt to remap it. 906 DoNotLinkFromSource.insert(SGA); 907 908 return false; 909 } 910 } 911 912 // If there is no linkage to be performed or we're linking from the source, 913 // bring over SGA. 914 GlobalAlias *NewDA = new GlobalAlias(TypeMap.get(SGA->getType()), 915 SGA->getLinkage(), SGA->getName(), 916 /*aliasee*/0, DstM); 917 copyGVAttributes(NewDA, SGA); 918 if (NewVisibility) 919 NewDA->setVisibility(*NewVisibility); 920 921 if (DGV) { 922 // Any uses of DGV need to change to NewDA, with cast. 923 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDA, DGV->getType())); 924 DGV->eraseFromParent(); 925 } 926 927 ValueMap[SGA] = NewDA; 928 return false; 929} 930 931static void getArrayElements(Constant *C, SmallVectorImpl<Constant*> &Dest) { 932 unsigned NumElements = cast<ArrayType>(C->getType())->getNumElements(); 933 934 for (unsigned i = 0; i != NumElements; ++i) 935 Dest.push_back(C->getAggregateElement(i)); 936} 937 938void ModuleLinker::linkAppendingVarInit(const AppendingVarInfo &AVI) { 939 // Merge the initializer. 940 SmallVector<Constant*, 16> Elements; 941 getArrayElements(AVI.DstInit, Elements); 942 943 Constant *SrcInit = MapValue(AVI.SrcInit, ValueMap, RF_None, &TypeMap, &ValMaterializer); 944 getArrayElements(SrcInit, Elements); 945 946 ArrayType *NewType = cast<ArrayType>(AVI.NewGV->getType()->getElementType()); 947 AVI.NewGV->setInitializer(ConstantArray::get(NewType, Elements)); 948} 949 950/// linkGlobalInits - Update the initializers in the Dest module now that all 951/// globals that may be referenced are in Dest. 952void ModuleLinker::linkGlobalInits() { 953 // Loop over all of the globals in the src module, mapping them over as we go 954 for (Module::const_global_iterator I = SrcM->global_begin(), 955 E = SrcM->global_end(); I != E; ++I) { 956 957 // Only process initialized GV's or ones not already in dest. 958 if (!I->hasInitializer() || DoNotLinkFromSource.count(I)) continue; 959 960 // Grab destination global variable. 961 GlobalVariable *DGV = cast<GlobalVariable>(ValueMap[I]); 962 // Figure out what the initializer looks like in the dest module. 963 DGV->setInitializer(MapValue(I->getInitializer(), ValueMap, 964 RF_None, &TypeMap, &ValMaterializer)); 965 } 966} 967 968/// linkFunctionBody - Copy the source function over into the dest function and 969/// fix up references to values. At this point we know that Dest is an external 970/// function, and that Src is not. 971void ModuleLinker::linkFunctionBody(Function *Dst, Function *Src) { 972 assert(Src && Dst && Dst->isDeclaration() && !Src->isDeclaration()); 973 974 // Go through and convert function arguments over, remembering the mapping. 975 Function::arg_iterator DI = Dst->arg_begin(); 976 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end(); 977 I != E; ++I, ++DI) { 978 DI->setName(I->getName()); // Copy the name over. 979 980 // Add a mapping to our mapping. 981 ValueMap[I] = DI; 982 } 983 984 if (Mode == Linker::DestroySource) { 985 // Splice the body of the source function into the dest function. 986 Dst->getBasicBlockList().splice(Dst->end(), Src->getBasicBlockList()); 987 988 // At this point, all of the instructions and values of the function are now 989 // copied over. The only problem is that they are still referencing values in 990 // the Source function as operands. Loop through all of the operands of the 991 // functions and patch them up to point to the local versions. 992 for (Function::iterator BB = Dst->begin(), BE = Dst->end(); BB != BE; ++BB) 993 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) 994 RemapInstruction(I, ValueMap, RF_IgnoreMissingEntries, 995 &TypeMap, &ValMaterializer); 996 997 } else { 998 // Clone the body of the function into the dest function. 999 SmallVector<ReturnInst*, 8> Returns; // Ignore returns. 1000 CloneFunctionInto(Dst, Src, ValueMap, false, Returns, "", NULL, 1001 &TypeMap, &ValMaterializer); 1002 } 1003 1004 // There is no need to map the arguments anymore. 1005 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end(); 1006 I != E; ++I) 1007 ValueMap.erase(I); 1008 1009} 1010 1011/// linkAliasBodies - Insert all of the aliases in Src into the Dest module. 1012void ModuleLinker::linkAliasBodies() { 1013 for (Module::alias_iterator I = SrcM->alias_begin(), E = SrcM->alias_end(); 1014 I != E; ++I) { 1015 if (DoNotLinkFromSource.count(I)) 1016 continue; 1017 if (Constant *Aliasee = I->getAliasee()) { 1018 GlobalAlias *DA = cast<GlobalAlias>(ValueMap[I]); 1019 DA->setAliasee(MapValue(Aliasee, ValueMap, RF_None, 1020 &TypeMap, &ValMaterializer)); 1021 } 1022 } 1023} 1024 1025/// linkNamedMDNodes - Insert all of the named MDNodes in Src into the Dest 1026/// module. 1027void ModuleLinker::linkNamedMDNodes() { 1028 const NamedMDNode *SrcModFlags = SrcM->getModuleFlagsMetadata(); 1029 for (Module::const_named_metadata_iterator I = SrcM->named_metadata_begin(), 1030 E = SrcM->named_metadata_end(); I != E; ++I) { 1031 // Don't link module flags here. Do them separately. 1032 if (&*I == SrcModFlags) continue; 1033 NamedMDNode *DestNMD = DstM->getOrInsertNamedMetadata(I->getName()); 1034 // Add Src elements into Dest node. 1035 for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) 1036 DestNMD->addOperand(MapValue(I->getOperand(i), ValueMap, 1037 RF_None, &TypeMap, &ValMaterializer)); 1038 } 1039} 1040 1041/// linkModuleFlagsMetadata - Merge the linker flags in Src into the Dest 1042/// module. 1043bool ModuleLinker::linkModuleFlagsMetadata() { 1044 // If the source module has no module flags, we are done. 1045 const NamedMDNode *SrcModFlags = SrcM->getModuleFlagsMetadata(); 1046 if (!SrcModFlags) return false; 1047 1048 // If the destination module doesn't have module flags yet, then just copy 1049 // over the source module's flags. 1050 NamedMDNode *DstModFlags = DstM->getOrInsertModuleFlagsMetadata(); 1051 if (DstModFlags->getNumOperands() == 0) { 1052 for (unsigned I = 0, E = SrcModFlags->getNumOperands(); I != E; ++I) 1053 DstModFlags->addOperand(SrcModFlags->getOperand(I)); 1054 1055 return false; 1056 } 1057 1058 // First build a map of the existing module flags and requirements. 1059 DenseMap<MDString*, MDNode*> Flags; 1060 SmallSetVector<MDNode*, 16> Requirements; 1061 for (unsigned I = 0, E = DstModFlags->getNumOperands(); I != E; ++I) { 1062 MDNode *Op = DstModFlags->getOperand(I); 1063 ConstantInt *Behavior = cast<ConstantInt>(Op->getOperand(0)); 1064 MDString *ID = cast<MDString>(Op->getOperand(1)); 1065 1066 if (Behavior->getZExtValue() == Module::Require) { 1067 Requirements.insert(cast<MDNode>(Op->getOperand(2))); 1068 } else { 1069 Flags[ID] = Op; 1070 } 1071 } 1072 1073 // Merge in the flags from the source module, and also collect its set of 1074 // requirements. 1075 bool HasErr = false; 1076 for (unsigned I = 0, E = SrcModFlags->getNumOperands(); I != E; ++I) { 1077 MDNode *SrcOp = SrcModFlags->getOperand(I); 1078 ConstantInt *SrcBehavior = cast<ConstantInt>(SrcOp->getOperand(0)); 1079 MDString *ID = cast<MDString>(SrcOp->getOperand(1)); 1080 MDNode *DstOp = Flags.lookup(ID); 1081 unsigned SrcBehaviorValue = SrcBehavior->getZExtValue(); 1082 1083 // If this is a requirement, add it and continue. 1084 if (SrcBehaviorValue == Module::Require) { 1085 // If the destination module does not already have this requirement, add 1086 // it. 1087 if (Requirements.insert(cast<MDNode>(SrcOp->getOperand(2)))) { 1088 DstModFlags->addOperand(SrcOp); 1089 } 1090 continue; 1091 } 1092 1093 // If there is no existing flag with this ID, just add it. 1094 if (!DstOp) { 1095 Flags[ID] = SrcOp; 1096 DstModFlags->addOperand(SrcOp); 1097 continue; 1098 } 1099 1100 // Otherwise, perform a merge. 1101 ConstantInt *DstBehavior = cast<ConstantInt>(DstOp->getOperand(0)); 1102 unsigned DstBehaviorValue = DstBehavior->getZExtValue(); 1103 1104 // If either flag has override behavior, handle it first. 1105 if (DstBehaviorValue == Module::Override) { 1106 // Diagnose inconsistent flags which both have override behavior. 1107 if (SrcBehaviorValue == Module::Override && 1108 SrcOp->getOperand(2) != DstOp->getOperand(2)) { 1109 HasErr |= emitError("linking module flags '" + ID->getString() + 1110 "': IDs have conflicting override values"); 1111 } 1112 continue; 1113 } else if (SrcBehaviorValue == Module::Override) { 1114 // Update the destination flag to that of the source. 1115 DstOp->replaceOperandWith(0, SrcBehavior); 1116 DstOp->replaceOperandWith(2, SrcOp->getOperand(2)); 1117 continue; 1118 } 1119 1120 // Diagnose inconsistent merge behavior types. 1121 if (SrcBehaviorValue != DstBehaviorValue) { 1122 HasErr |= emitError("linking module flags '" + ID->getString() + 1123 "': IDs have conflicting behaviors"); 1124 continue; 1125 } 1126 1127 // Perform the merge for standard behavior types. 1128 switch (SrcBehaviorValue) { 1129 case Module::Require: 1130 case Module::Override: assert(0 && "not possible"); break; 1131 case Module::Error: { 1132 // Emit an error if the values differ. 1133 if (SrcOp->getOperand(2) != DstOp->getOperand(2)) { 1134 HasErr |= emitError("linking module flags '" + ID->getString() + 1135 "': IDs have conflicting values"); 1136 } 1137 continue; 1138 } 1139 case Module::Warning: { 1140 // Emit a warning if the values differ. 1141 if (SrcOp->getOperand(2) != DstOp->getOperand(2)) { 1142 if (!SuppressWarnings) { 1143 errs() << "WARNING: linking module flags '" << ID->getString() 1144 << "': IDs have conflicting values"; 1145 } 1146 } 1147 continue; 1148 } 1149 case Module::Append: { 1150 MDNode *DstValue = cast<MDNode>(DstOp->getOperand(2)); 1151 MDNode *SrcValue = cast<MDNode>(SrcOp->getOperand(2)); 1152 unsigned NumOps = DstValue->getNumOperands() + SrcValue->getNumOperands(); 1153 Value **VP, **Values = VP = new Value*[NumOps]; 1154 for (unsigned i = 0, e = DstValue->getNumOperands(); i != e; ++i, ++VP) 1155 *VP = DstValue->getOperand(i); 1156 for (unsigned i = 0, e = SrcValue->getNumOperands(); i != e; ++i, ++VP) 1157 *VP = SrcValue->getOperand(i); 1158 DstOp->replaceOperandWith(2, MDNode::get(DstM->getContext(), 1159 ArrayRef<Value*>(Values, 1160 NumOps))); 1161 delete[] Values; 1162 break; 1163 } 1164 case Module::AppendUnique: { 1165 SmallSetVector<Value*, 16> Elts; 1166 MDNode *DstValue = cast<MDNode>(DstOp->getOperand(2)); 1167 MDNode *SrcValue = cast<MDNode>(SrcOp->getOperand(2)); 1168 for (unsigned i = 0, e = DstValue->getNumOperands(); i != e; ++i) 1169 Elts.insert(DstValue->getOperand(i)); 1170 for (unsigned i = 0, e = SrcValue->getNumOperands(); i != e; ++i) 1171 Elts.insert(SrcValue->getOperand(i)); 1172 DstOp->replaceOperandWith(2, MDNode::get(DstM->getContext(), 1173 ArrayRef<Value*>(Elts.begin(), 1174 Elts.end()))); 1175 break; 1176 } 1177 } 1178 } 1179 1180 // Check all of the requirements. 1181 for (unsigned I = 0, E = Requirements.size(); I != E; ++I) { 1182 MDNode *Requirement = Requirements[I]; 1183 MDString *Flag = cast<MDString>(Requirement->getOperand(0)); 1184 Value *ReqValue = Requirement->getOperand(1); 1185 1186 MDNode *Op = Flags[Flag]; 1187 if (!Op || Op->getOperand(2) != ReqValue) { 1188 HasErr |= emitError("linking module flags '" + Flag->getString() + 1189 "': does not have the required value"); 1190 continue; 1191 } 1192 } 1193 1194 return HasErr; 1195} 1196 1197bool ModuleLinker::run() { 1198 assert(DstM && "Null destination module"); 1199 assert(SrcM && "Null source module"); 1200 1201 // Inherit the target data from the source module if the destination module 1202 // doesn't have one already. 1203 if (!DstM->getDataLayout() && SrcM->getDataLayout()) 1204 DstM->setDataLayout(SrcM->getDataLayout()); 1205 1206 // Copy the target triple from the source to dest if the dest's is empty. 1207 if (DstM->getTargetTriple().empty() && !SrcM->getTargetTriple().empty()) 1208 DstM->setTargetTriple(SrcM->getTargetTriple()); 1209 1210 if (SrcM->getDataLayout() && DstM->getDataLayout() && 1211 *SrcM->getDataLayout() != *DstM->getDataLayout()) { 1212 if (!SuppressWarnings) { 1213 errs() << "WARNING: Linking two modules of different data layouts: '" 1214 << SrcM->getModuleIdentifier() << "' is '" 1215 << SrcM->getDataLayoutStr() << "' whereas '" 1216 << DstM->getModuleIdentifier() << "' is '" 1217 << DstM->getDataLayoutStr() << "'\n"; 1218 } 1219 } 1220 if (!SrcM->getTargetTriple().empty() && 1221 DstM->getTargetTriple() != SrcM->getTargetTriple()) { 1222 if (!SuppressWarnings) { 1223 errs() << "WARNING: Linking two modules of different target triples: " 1224 << SrcM->getModuleIdentifier() << "' is '" 1225 << SrcM->getTargetTriple() << "' whereas '" 1226 << DstM->getModuleIdentifier() << "' is '" 1227 << DstM->getTargetTriple() << "'\n"; 1228 } 1229 } 1230 1231 // Append the module inline asm string. 1232 if (!SrcM->getModuleInlineAsm().empty()) { 1233 if (DstM->getModuleInlineAsm().empty()) 1234 DstM->setModuleInlineAsm(SrcM->getModuleInlineAsm()); 1235 else 1236 DstM->setModuleInlineAsm(DstM->getModuleInlineAsm()+"\n"+ 1237 SrcM->getModuleInlineAsm()); 1238 } 1239 1240 // Loop over all of the linked values to compute type mappings. 1241 computeTypeMapping(); 1242 1243 // Insert all of the globals in src into the DstM module... without linking 1244 // initializers (which could refer to functions not yet mapped over). 1245 for (Module::global_iterator I = SrcM->global_begin(), 1246 E = SrcM->global_end(); I != E; ++I) 1247 if (linkGlobalProto(I)) 1248 return true; 1249 1250 // Link the functions together between the two modules, without doing function 1251 // bodies... this just adds external function prototypes to the DstM 1252 // function... We do this so that when we begin processing function bodies, 1253 // all of the global values that may be referenced are available in our 1254 // ValueMap. 1255 for (Module::iterator I = SrcM->begin(), E = SrcM->end(); I != E; ++I) 1256 if (linkFunctionProto(I)) 1257 return true; 1258 1259 // If there were any aliases, link them now. 1260 for (Module::alias_iterator I = SrcM->alias_begin(), 1261 E = SrcM->alias_end(); I != E; ++I) 1262 if (linkAliasProto(I)) 1263 return true; 1264 1265 for (unsigned i = 0, e = AppendingVars.size(); i != e; ++i) 1266 linkAppendingVarInit(AppendingVars[i]); 1267 1268 // Link in the function bodies that are defined in the source module into 1269 // DstM. 1270 for (Module::iterator SF = SrcM->begin(), E = SrcM->end(); SF != E; ++SF) { 1271 // Skip if not linking from source. 1272 if (DoNotLinkFromSource.count(SF)) continue; 1273 1274 Function *DF = cast<Function>(ValueMap[SF]); 1275 if (SF->hasPrefixData()) { 1276 // Link in the prefix data. 1277 DF->setPrefixData(MapValue( 1278 SF->getPrefixData(), ValueMap, RF_None, &TypeMap, &ValMaterializer)); 1279 } 1280 1281 // Skip if no body (function is external) or materialize. 1282 if (SF->isDeclaration()) { 1283 if (!SF->isMaterializable()) 1284 continue; 1285 if (SF->Materialize(&ErrorMsg)) 1286 return true; 1287 } 1288 1289 linkFunctionBody(DF, SF); 1290 SF->Dematerialize(); 1291 } 1292 1293 // Resolve all uses of aliases with aliasees. 1294 linkAliasBodies(); 1295 1296 // Remap all of the named MDNodes in Src into the DstM module. We do this 1297 // after linking GlobalValues so that MDNodes that reference GlobalValues 1298 // are properly remapped. 1299 linkNamedMDNodes(); 1300 1301 // Merge the module flags into the DstM module. 1302 if (linkModuleFlagsMetadata()) 1303 return true; 1304 1305 // Update the initializers in the DstM module now that all globals that may 1306 // be referenced are in DstM. 1307 linkGlobalInits(); 1308 1309 // Process vector of lazily linked in functions. 1310 bool LinkedInAnyFunctions; 1311 do { 1312 LinkedInAnyFunctions = false; 1313 1314 for(std::vector<Function*>::iterator I = LazilyLinkFunctions.begin(), 1315 E = LazilyLinkFunctions.end(); I != E; ++I) { 1316 Function *SF = *I; 1317 if (!SF) 1318 continue; 1319 1320 Function *DF = cast<Function>(ValueMap[SF]); 1321 if (SF->hasPrefixData()) { 1322 // Link in the prefix data. 1323 DF->setPrefixData(MapValue(SF->getPrefixData(), 1324 ValueMap, 1325 RF_None, 1326 &TypeMap, 1327 &ValMaterializer)); 1328 } 1329 1330 // Materialize if necessary. 1331 if (SF->isDeclaration()) { 1332 if (!SF->isMaterializable()) 1333 continue; 1334 if (SF->Materialize(&ErrorMsg)) 1335 return true; 1336 } 1337 1338 // Erase from vector *before* the function body is linked - linkFunctionBody could 1339 // invalidate I. 1340 LazilyLinkFunctions.erase(I); 1341 1342 // Link in function body. 1343 linkFunctionBody(DF, SF); 1344 SF->Dematerialize(); 1345 1346 // Set flag to indicate we may have more functions to lazily link in 1347 // since we linked in a function. 1348 LinkedInAnyFunctions = true; 1349 break; 1350 } 1351 } while (LinkedInAnyFunctions); 1352 1353 // Now that all of the types from the source are used, resolve any structs 1354 // copied over to the dest that didn't exist there. 1355 TypeMap.linkDefinedTypeBodies(); 1356 1357 return false; 1358} 1359 1360Linker::Linker(Module *M, bool SuppressWarnings) 1361 : Composite(M), SuppressWarnings(SuppressWarnings) { 1362 TypeFinder StructTypes; 1363 StructTypes.run(*M, true); 1364 IdentifiedStructTypes.insert(StructTypes.begin(), StructTypes.end()); 1365} 1366 1367Linker::~Linker() { 1368} 1369 1370void Linker::deleteModule() { 1371 delete Composite; 1372 Composite = NULL; 1373} 1374 1375bool Linker::linkInModule(Module *Src, unsigned Mode, std::string *ErrorMsg) { 1376 ModuleLinker TheLinker(Composite, IdentifiedStructTypes, Src, Mode, 1377 SuppressWarnings); 1378 if (TheLinker.run()) { 1379 if (ErrorMsg) 1380 *ErrorMsg = TheLinker.ErrorMsg; 1381 return true; 1382 } 1383 return false; 1384} 1385 1386//===----------------------------------------------------------------------===// 1387// LinkModules entrypoint. 1388//===----------------------------------------------------------------------===// 1389 1390/// LinkModules - This function links two modules together, with the resulting 1391/// Dest module modified to be the composite of the two input modules. If an 1392/// error occurs, true is returned and ErrorMsg (if not null) is set to indicate 1393/// the problem. Upon failure, the Dest module could be in a modified state, 1394/// and shouldn't be relied on to be consistent. 1395bool Linker::LinkModules(Module *Dest, Module *Src, unsigned Mode, 1396 std::string *ErrorMsg) { 1397 Linker L(Dest); 1398 return L.linkInModule(Src, Mode, ErrorMsg); 1399} 1400 1401//===----------------------------------------------------------------------===// 1402// C API. 1403//===----------------------------------------------------------------------===// 1404 1405LLVMBool LLVMLinkModules(LLVMModuleRef Dest, LLVMModuleRef Src, 1406 LLVMLinkerMode Mode, char **OutMessages) { 1407 std::string Messages; 1408 LLVMBool Result = Linker::LinkModules(unwrap(Dest), unwrap(Src), 1409 Mode, OutMessages? &Messages : 0); 1410 if (OutMessages) 1411 *OutMessages = strdup(Messages.c_str()); 1412 return Result; 1413} 1414