1//===- lib/Linker/LinkModules.cpp - Module Linker Implementation ----------===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file implements the LLVM module linker. 11// 12//===----------------------------------------------------------------------===// 13 14#include "llvm/Linker.h" 15#include "llvm-c/Linker.h" 16#include "llvm/ADT/Optional.h" 17#include "llvm/ADT/SetVector.h" 18#include "llvm/ADT/SmallString.h" 19#include "llvm/IR/Constants.h" 20#include "llvm/IR/Module.h" 21#include "llvm/IR/TypeFinder.h" 22#include "llvm/Support/Debug.h" 23#include "llvm/Support/raw_ostream.h" 24#include "llvm/Transforms/Utils/Cloning.h" 25using namespace llvm; 26 27//===----------------------------------------------------------------------===// 28// TypeMap implementation. 29//===----------------------------------------------------------------------===// 30 31namespace { 32 typedef SmallPtrSet<StructType*, 32> TypeSet; 33 34class TypeMapTy : public ValueMapTypeRemapper { 35 /// MappedTypes - This is a mapping from a source type to a destination type 36 /// to use. 37 DenseMap<Type*, Type*> MappedTypes; 38 39 /// SpeculativeTypes - When checking to see if two subgraphs are isomorphic, 40 /// we speculatively add types to MappedTypes, but keep track of them here in 41 /// case we need to roll back. 42 SmallVector<Type*, 16> SpeculativeTypes; 43 44 /// SrcDefinitionsToResolve - This is a list of non-opaque structs in the 45 /// source module that are mapped to an opaque struct in the destination 46 /// module. 47 SmallVector<StructType*, 16> SrcDefinitionsToResolve; 48 49 /// DstResolvedOpaqueTypes - This is the set of opaque types in the 50 /// destination modules who are getting a body from the source module. 51 SmallPtrSet<StructType*, 16> DstResolvedOpaqueTypes; 52 53public: 54 TypeMapTy(TypeSet &Set) : DstStructTypesSet(Set) {} 55 56 TypeSet &DstStructTypesSet; 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<VectorType>(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 // A named structure type from src module is used. Add it to the Set of 335 // identified structs in the destination module. 336 DstStructTypesSet.insert(STy); 337 return *Entry = STy; 338 } 339 340 // Otherwise we create a new type and resolve its body later. This will be 341 // resolved by the top level of get(). 342 SrcDefinitionsToResolve.push_back(STy); 343 StructType *DTy = StructType::create(STy->getContext()); 344 // A new identified structure type was created. Add it to the set of 345 // identified structs in the destination module. 346 DstStructTypesSet.insert(DTy); 347 DstResolvedOpaqueTypes.insert(DTy); 348 return *Entry = DTy; 349} 350 351//===----------------------------------------------------------------------===// 352// ModuleLinker implementation. 353//===----------------------------------------------------------------------===// 354 355namespace { 356 /// ModuleLinker - This is an implementation class for the LinkModules 357 /// function, which is the entrypoint for this file. 358 class ModuleLinker { 359 Module *DstM, *SrcM; 360 361 TypeMapTy TypeMap; 362 363 /// ValueMap - Mapping of values from what they used to be in Src, to what 364 /// they are now in DstM. ValueToValueMapTy is a ValueMap, which involves 365 /// some overhead due to the use of Value handles which the Linker doesn't 366 /// actually need, but this allows us to reuse the ValueMapper code. 367 ValueToValueMapTy ValueMap; 368 369 struct AppendingVarInfo { 370 GlobalVariable *NewGV; // New aggregate global in dest module. 371 Constant *DstInit; // Old initializer from dest module. 372 Constant *SrcInit; // Old initializer from src module. 373 }; 374 375 std::vector<AppendingVarInfo> AppendingVars; 376 377 unsigned Mode; // Mode to treat source module. 378 379 // Set of items not to link in from source. 380 SmallPtrSet<const Value*, 16> DoNotLinkFromSource; 381 382 // Vector of functions to lazily link in. 383 std::vector<Function*> LazilyLinkFunctions; 384 385 public: 386 std::string ErrorMsg; 387 388 ModuleLinker(Module *dstM, TypeSet &Set, Module *srcM, unsigned mode) 389 : DstM(dstM), SrcM(srcM), TypeMap(Set), Mode(mode) { } 390 391 bool run(); 392 393 private: 394 /// emitError - Helper method for setting a message and returning an error 395 /// code. 396 bool emitError(const Twine &Message) { 397 ErrorMsg = Message.str(); 398 return true; 399 } 400 401 /// getLinkageResult - This analyzes the two global values and determines 402 /// what the result will look like in the destination module. 403 bool getLinkageResult(GlobalValue *Dest, const GlobalValue *Src, 404 GlobalValue::LinkageTypes <, 405 GlobalValue::VisibilityTypes &Vis, 406 bool &LinkFromSrc); 407 408 /// getLinkedToGlobal - Given a global in the source module, return the 409 /// global in the destination module that is being linked to, if any. 410 GlobalValue *getLinkedToGlobal(GlobalValue *SrcGV) { 411 // If the source has no name it can't link. If it has local linkage, 412 // there is no name match-up going on. 413 if (!SrcGV->hasName() || SrcGV->hasLocalLinkage()) 414 return 0; 415 416 // Otherwise see if we have a match in the destination module's symtab. 417 GlobalValue *DGV = DstM->getNamedValue(SrcGV->getName()); 418 if (DGV == 0) return 0; 419 420 // If we found a global with the same name in the dest module, but it has 421 // internal linkage, we are really not doing any linkage here. 422 if (DGV->hasLocalLinkage()) 423 return 0; 424 425 // Otherwise, we do in fact link to the destination global. 426 return DGV; 427 } 428 429 void computeTypeMapping(); 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 TypeFinder SrcStructTypes; 599 SrcStructTypes.run(*SrcM, true); 600 SmallPtrSet<StructType*, 32> SrcStructTypesSet(SrcStructTypes.begin(), 601 SrcStructTypes.end()); 602 603 for (unsigned i = 0, e = SrcStructTypes.size(); i != e; ++i) { 604 StructType *ST = SrcStructTypes[i]; 605 if (!ST->hasName()) continue; 606 607 // Check to see if there is a dot in the name followed by a digit. 608 size_t DotPos = ST->getName().rfind('.'); 609 if (DotPos == 0 || DotPos == StringRef::npos || 610 ST->getName().back() == '.' || 611 !isdigit(static_cast<unsigned char>(ST->getName()[DotPos+1]))) 612 continue; 613 614 // Check to see if the destination module has a struct with the prefix name. 615 if (StructType *DST = DstM->getTypeByName(ST->getName().substr(0, DotPos))) 616 // Don't use it if this actually came from the source module. They're in 617 // the same LLVMContext after all. Also don't use it unless the type is 618 // actually used in the destination module. This can happen in situations 619 // like this: 620 // 621 // Module A Module B 622 // -------- -------- 623 // %Z = type { %A } %B = type { %C.1 } 624 // %A = type { %B.1, [7 x i8] } %C.1 = type { i8* } 625 // %B.1 = type { %C } %A.2 = type { %B.3, [5 x i8] } 626 // %C = type { i8* } %B.3 = type { %C.1 } 627 // 628 // When we link Module B with Module A, the '%B' in Module B is 629 // used. However, that would then use '%C.1'. But when we process '%C.1', 630 // we prefer to take the '%C' version. So we are then left with both 631 // '%C.1' and '%C' being used for the same types. This leads to some 632 // variables using one type and some using the other. 633 if (!SrcStructTypesSet.count(DST) && TypeMap.DstStructTypesSet.count(DST)) 634 TypeMap.addTypeMapping(DST, ST); 635 } 636 637 // Don't bother incorporating aliases, they aren't generally typed well. 638 639 // Now that we have discovered all of the type equivalences, get a body for 640 // any 'opaque' types in the dest module that are now resolved. 641 TypeMap.linkDefinedTypeBodies(); 642} 643 644/// linkAppendingVarProto - If there were any appending global variables, link 645/// them together now. Return true on error. 646bool ModuleLinker::linkAppendingVarProto(GlobalVariable *DstGV, 647 GlobalVariable *SrcGV) { 648 649 if (!SrcGV->hasAppendingLinkage() || !DstGV->hasAppendingLinkage()) 650 return emitError("Linking globals named '" + SrcGV->getName() + 651 "': can only link appending global with another appending global!"); 652 653 ArrayType *DstTy = cast<ArrayType>(DstGV->getType()->getElementType()); 654 ArrayType *SrcTy = 655 cast<ArrayType>(TypeMap.get(SrcGV->getType()->getElementType())); 656 Type *EltTy = DstTy->getElementType(); 657 658 // Check to see that they two arrays agree on type. 659 if (EltTy != SrcTy->getElementType()) 660 return emitError("Appending variables with different element types!"); 661 if (DstGV->isConstant() != SrcGV->isConstant()) 662 return emitError("Appending variables linked with different const'ness!"); 663 664 if (DstGV->getAlignment() != SrcGV->getAlignment()) 665 return emitError( 666 "Appending variables with different alignment need to be linked!"); 667 668 if (DstGV->getVisibility() != SrcGV->getVisibility()) 669 return emitError( 670 "Appending variables with different visibility need to be linked!"); 671 672 if (DstGV->getSection() != SrcGV->getSection()) 673 return emitError( 674 "Appending variables with different section name need to be linked!"); 675 676 uint64_t NewSize = DstTy->getNumElements() + SrcTy->getNumElements(); 677 ArrayType *NewType = ArrayType::get(EltTy, NewSize); 678 679 // Create the new global variable. 680 GlobalVariable *NG = 681 new GlobalVariable(*DstGV->getParent(), NewType, SrcGV->isConstant(), 682 DstGV->getLinkage(), /*init*/0, /*name*/"", DstGV, 683 DstGV->getThreadLocalMode(), 684 DstGV->getType()->getAddressSpace()); 685 686 // Propagate alignment, visibility and section info. 687 copyGVAttributes(NG, DstGV); 688 689 AppendingVarInfo AVI; 690 AVI.NewGV = NG; 691 AVI.DstInit = DstGV->getInitializer(); 692 AVI.SrcInit = SrcGV->getInitializer(); 693 AppendingVars.push_back(AVI); 694 695 // Replace any uses of the two global variables with uses of the new 696 // global. 697 ValueMap[SrcGV] = ConstantExpr::getBitCast(NG, TypeMap.get(SrcGV->getType())); 698 699 DstGV->replaceAllUsesWith(ConstantExpr::getBitCast(NG, DstGV->getType())); 700 DstGV->eraseFromParent(); 701 702 // Track the source variable so we don't try to link it. 703 DoNotLinkFromSource.insert(SrcGV); 704 705 return false; 706} 707 708/// linkGlobalProto - Loop through the global variables in the src module and 709/// merge them into the dest module. 710bool ModuleLinker::linkGlobalProto(GlobalVariable *SGV) { 711 GlobalValue *DGV = getLinkedToGlobal(SGV); 712 llvm::Optional<GlobalValue::VisibilityTypes> NewVisibility; 713 714 if (DGV) { 715 // Concatenation of appending linkage variables is magic and handled later. 716 if (DGV->hasAppendingLinkage() || SGV->hasAppendingLinkage()) 717 return linkAppendingVarProto(cast<GlobalVariable>(DGV), SGV); 718 719 // Determine whether linkage of these two globals follows the source 720 // module's definition or the destination module's definition. 721 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; 722 GlobalValue::VisibilityTypes NV; 723 bool LinkFromSrc = false; 724 if (getLinkageResult(DGV, SGV, NewLinkage, NV, LinkFromSrc)) 725 return true; 726 NewVisibility = NV; 727 728 // If we're not linking from the source, then keep the definition that we 729 // have. 730 if (!LinkFromSrc) { 731 // Special case for const propagation. 732 if (GlobalVariable *DGVar = dyn_cast<GlobalVariable>(DGV)) 733 if (DGVar->isDeclaration() && SGV->isConstant() && !DGVar->isConstant()) 734 DGVar->setConstant(true); 735 736 // Set calculated linkage and visibility. 737 DGV->setLinkage(NewLinkage); 738 DGV->setVisibility(*NewVisibility); 739 740 // Make sure to remember this mapping. 741 ValueMap[SGV] = ConstantExpr::getBitCast(DGV,TypeMap.get(SGV->getType())); 742 743 // Track the source global so that we don't attempt to copy it over when 744 // processing global initializers. 745 DoNotLinkFromSource.insert(SGV); 746 747 return false; 748 } 749 } 750 751 // No linking to be performed or linking from the source: simply create an 752 // identical version of the symbol over in the dest module... the 753 // initializer will be filled in later by LinkGlobalInits. 754 GlobalVariable *NewDGV = 755 new GlobalVariable(*DstM, TypeMap.get(SGV->getType()->getElementType()), 756 SGV->isConstant(), SGV->getLinkage(), /*init*/0, 757 SGV->getName(), /*insertbefore*/0, 758 SGV->getThreadLocalMode(), 759 SGV->getType()->getAddressSpace()); 760 // Propagate alignment, visibility and section info. 761 copyGVAttributes(NewDGV, SGV); 762 if (NewVisibility) 763 NewDGV->setVisibility(*NewVisibility); 764 765 if (DGV) { 766 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDGV, DGV->getType())); 767 DGV->eraseFromParent(); 768 } 769 770 // Make sure to remember this mapping. 771 ValueMap[SGV] = NewDGV; 772 return false; 773} 774 775/// linkFunctionProto - Link the function in the source module into the 776/// destination module if needed, setting up mapping information. 777bool ModuleLinker::linkFunctionProto(Function *SF) { 778 GlobalValue *DGV = getLinkedToGlobal(SF); 779 llvm::Optional<GlobalValue::VisibilityTypes> NewVisibility; 780 781 if (DGV) { 782 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; 783 bool LinkFromSrc = false; 784 GlobalValue::VisibilityTypes NV; 785 if (getLinkageResult(DGV, SF, NewLinkage, NV, LinkFromSrc)) 786 return true; 787 NewVisibility = NV; 788 789 if (!LinkFromSrc) { 790 // Set calculated linkage 791 DGV->setLinkage(NewLinkage); 792 DGV->setVisibility(*NewVisibility); 793 794 // Make sure to remember this mapping. 795 ValueMap[SF] = ConstantExpr::getBitCast(DGV, TypeMap.get(SF->getType())); 796 797 // Track the function from the source module so we don't attempt to remap 798 // it. 799 DoNotLinkFromSource.insert(SF); 800 801 return false; 802 } 803 } 804 805 // If there is no linkage to be performed or we are linking from the source, 806 // bring SF over. 807 Function *NewDF = Function::Create(TypeMap.get(SF->getFunctionType()), 808 SF->getLinkage(), SF->getName(), DstM); 809 copyGVAttributes(NewDF, SF); 810 if (NewVisibility) 811 NewDF->setVisibility(*NewVisibility); 812 813 if (DGV) { 814 // Any uses of DF need to change to NewDF, with cast. 815 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDF, DGV->getType())); 816 DGV->eraseFromParent(); 817 } else { 818 // Internal, LO_ODR, or LO linkage - stick in set to ignore and lazily link. 819 if (SF->hasLocalLinkage() || SF->hasLinkOnceLinkage() || 820 SF->hasAvailableExternallyLinkage()) { 821 DoNotLinkFromSource.insert(SF); 822 LazilyLinkFunctions.push_back(SF); 823 } 824 } 825 826 ValueMap[SF] = NewDF; 827 return false; 828} 829 830/// LinkAliasProto - Set up prototypes for any aliases that come over from the 831/// source module. 832bool ModuleLinker::linkAliasProto(GlobalAlias *SGA) { 833 GlobalValue *DGV = getLinkedToGlobal(SGA); 834 llvm::Optional<GlobalValue::VisibilityTypes> NewVisibility; 835 836 if (DGV) { 837 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; 838 GlobalValue::VisibilityTypes NV; 839 bool LinkFromSrc = false; 840 if (getLinkageResult(DGV, SGA, NewLinkage, NV, LinkFromSrc)) 841 return true; 842 NewVisibility = NV; 843 844 if (!LinkFromSrc) { 845 // Set calculated linkage. 846 DGV->setLinkage(NewLinkage); 847 DGV->setVisibility(*NewVisibility); 848 849 // Make sure to remember this mapping. 850 ValueMap[SGA] = ConstantExpr::getBitCast(DGV,TypeMap.get(SGA->getType())); 851 852 // Track the alias from the source module so we don't attempt to remap it. 853 DoNotLinkFromSource.insert(SGA); 854 855 return false; 856 } 857 } 858 859 // If there is no linkage to be performed or we're linking from the source, 860 // bring over SGA. 861 GlobalAlias *NewDA = new GlobalAlias(TypeMap.get(SGA->getType()), 862 SGA->getLinkage(), SGA->getName(), 863 /*aliasee*/0, DstM); 864 copyGVAttributes(NewDA, SGA); 865 if (NewVisibility) 866 NewDA->setVisibility(*NewVisibility); 867 868 if (DGV) { 869 // Any uses of DGV need to change to NewDA, with cast. 870 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDA, DGV->getType())); 871 DGV->eraseFromParent(); 872 } 873 874 ValueMap[SGA] = NewDA; 875 return false; 876} 877 878static void getArrayElements(Constant *C, SmallVectorImpl<Constant*> &Dest) { 879 unsigned NumElements = cast<ArrayType>(C->getType())->getNumElements(); 880 881 for (unsigned i = 0; i != NumElements; ++i) 882 Dest.push_back(C->getAggregateElement(i)); 883} 884 885void ModuleLinker::linkAppendingVarInit(const AppendingVarInfo &AVI) { 886 // Merge the initializer. 887 SmallVector<Constant*, 16> Elements; 888 getArrayElements(AVI.DstInit, Elements); 889 890 Constant *SrcInit = MapValue(AVI.SrcInit, ValueMap, RF_None, &TypeMap); 891 getArrayElements(SrcInit, Elements); 892 893 ArrayType *NewType = cast<ArrayType>(AVI.NewGV->getType()->getElementType()); 894 AVI.NewGV->setInitializer(ConstantArray::get(NewType, Elements)); 895} 896 897/// linkGlobalInits - Update the initializers in the Dest module now that all 898/// globals that may be referenced are in Dest. 899void ModuleLinker::linkGlobalInits() { 900 // Loop over all of the globals in the src module, mapping them over as we go 901 for (Module::const_global_iterator I = SrcM->global_begin(), 902 E = SrcM->global_end(); I != E; ++I) { 903 904 // Only process initialized GV's or ones not already in dest. 905 if (!I->hasInitializer() || DoNotLinkFromSource.count(I)) continue; 906 907 // Grab destination global variable. 908 GlobalVariable *DGV = cast<GlobalVariable>(ValueMap[I]); 909 // Figure out what the initializer looks like in the dest module. 910 DGV->setInitializer(MapValue(I->getInitializer(), ValueMap, 911 RF_None, &TypeMap)); 912 } 913} 914 915/// linkFunctionBody - Copy the source function over into the dest function and 916/// fix up references to values. At this point we know that Dest is an external 917/// function, and that Src is not. 918void ModuleLinker::linkFunctionBody(Function *Dst, Function *Src) { 919 assert(Src && Dst && Dst->isDeclaration() && !Src->isDeclaration()); 920 921 // Go through and convert function arguments over, remembering the mapping. 922 Function::arg_iterator DI = Dst->arg_begin(); 923 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end(); 924 I != E; ++I, ++DI) { 925 DI->setName(I->getName()); // Copy the name over. 926 927 // Add a mapping to our mapping. 928 ValueMap[I] = DI; 929 } 930 931 if (Mode == Linker::DestroySource) { 932 // Splice the body of the source function into the dest function. 933 Dst->getBasicBlockList().splice(Dst->end(), Src->getBasicBlockList()); 934 935 // At this point, all of the instructions and values of the function are now 936 // copied over. The only problem is that they are still referencing values in 937 // the Source function as operands. Loop through all of the operands of the 938 // functions and patch them up to point to the local versions. 939 for (Function::iterator BB = Dst->begin(), BE = Dst->end(); BB != BE; ++BB) 940 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) 941 RemapInstruction(I, ValueMap, RF_IgnoreMissingEntries, &TypeMap); 942 943 } else { 944 // Clone the body of the function into the dest function. 945 SmallVector<ReturnInst*, 8> Returns; // Ignore returns. 946 CloneFunctionInto(Dst, Src, ValueMap, false, Returns, "", NULL, &TypeMap); 947 } 948 949 // There is no need to map the arguments anymore. 950 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end(); 951 I != E; ++I) 952 ValueMap.erase(I); 953 954} 955 956/// linkAliasBodies - Insert all of the aliases in Src into the Dest module. 957void ModuleLinker::linkAliasBodies() { 958 for (Module::alias_iterator I = SrcM->alias_begin(), E = SrcM->alias_end(); 959 I != E; ++I) { 960 if (DoNotLinkFromSource.count(I)) 961 continue; 962 if (Constant *Aliasee = I->getAliasee()) { 963 GlobalAlias *DA = cast<GlobalAlias>(ValueMap[I]); 964 DA->setAliasee(MapValue(Aliasee, ValueMap, RF_None, &TypeMap)); 965 } 966 } 967} 968 969/// linkNamedMDNodes - Insert all of the named MDNodes in Src into the Dest 970/// module. 971void ModuleLinker::linkNamedMDNodes() { 972 const NamedMDNode *SrcModFlags = SrcM->getModuleFlagsMetadata(); 973 for (Module::const_named_metadata_iterator I = SrcM->named_metadata_begin(), 974 E = SrcM->named_metadata_end(); I != E; ++I) { 975 // Don't link module flags here. Do them separately. 976 if (&*I == SrcModFlags) continue; 977 NamedMDNode *DestNMD = DstM->getOrInsertNamedMetadata(I->getName()); 978 // Add Src elements into Dest node. 979 for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) 980 DestNMD->addOperand(MapValue(I->getOperand(i), ValueMap, 981 RF_None, &TypeMap)); 982 } 983} 984 985/// linkModuleFlagsMetadata - Merge the linker flags in Src into the Dest 986/// module. 987bool ModuleLinker::linkModuleFlagsMetadata() { 988 // If the source module has no module flags, we are done. 989 const NamedMDNode *SrcModFlags = SrcM->getModuleFlagsMetadata(); 990 if (!SrcModFlags) return false; 991 992 // If the destination module doesn't have module flags yet, then just copy 993 // over the source module's flags. 994 NamedMDNode *DstModFlags = DstM->getOrInsertModuleFlagsMetadata(); 995 if (DstModFlags->getNumOperands() == 0) { 996 for (unsigned I = 0, E = SrcModFlags->getNumOperands(); I != E; ++I) 997 DstModFlags->addOperand(SrcModFlags->getOperand(I)); 998 999 return false; 1000 } 1001 1002 // First build a map of the existing module flags and requirements. 1003 DenseMap<MDString*, MDNode*> Flags; 1004 SmallSetVector<MDNode*, 16> Requirements; 1005 for (unsigned I = 0, E = DstModFlags->getNumOperands(); I != E; ++I) { 1006 MDNode *Op = DstModFlags->getOperand(I); 1007 ConstantInt *Behavior = cast<ConstantInt>(Op->getOperand(0)); 1008 MDString *ID = cast<MDString>(Op->getOperand(1)); 1009 1010 if (Behavior->getZExtValue() == Module::Require) { 1011 Requirements.insert(cast<MDNode>(Op->getOperand(2))); 1012 } else { 1013 Flags[ID] = Op; 1014 } 1015 } 1016 1017 // Merge in the flags from the source module, and also collect its set of 1018 // requirements. 1019 bool HasErr = false; 1020 for (unsigned I = 0, E = SrcModFlags->getNumOperands(); I != E; ++I) { 1021 MDNode *SrcOp = SrcModFlags->getOperand(I); 1022 ConstantInt *SrcBehavior = cast<ConstantInt>(SrcOp->getOperand(0)); 1023 MDString *ID = cast<MDString>(SrcOp->getOperand(1)); 1024 MDNode *DstOp = Flags.lookup(ID); 1025 unsigned SrcBehaviorValue = SrcBehavior->getZExtValue(); 1026 1027 // If this is a requirement, add it and continue. 1028 if (SrcBehaviorValue == Module::Require) { 1029 // If the destination module does not already have this requirement, add 1030 // it. 1031 if (Requirements.insert(cast<MDNode>(SrcOp->getOperand(2)))) { 1032 DstModFlags->addOperand(SrcOp); 1033 } 1034 continue; 1035 } 1036 1037 // If there is no existing flag with this ID, just add it. 1038 if (!DstOp) { 1039 Flags[ID] = SrcOp; 1040 DstModFlags->addOperand(SrcOp); 1041 continue; 1042 } 1043 1044 // Otherwise, perform a merge. 1045 ConstantInt *DstBehavior = cast<ConstantInt>(DstOp->getOperand(0)); 1046 unsigned DstBehaviorValue = DstBehavior->getZExtValue(); 1047 1048 // If either flag has override behavior, handle it first. 1049 if (DstBehaviorValue == Module::Override) { 1050 // Diagnose inconsistent flags which both have override behavior. 1051 if (SrcBehaviorValue == Module::Override && 1052 SrcOp->getOperand(2) != DstOp->getOperand(2)) { 1053 HasErr |= emitError("linking module flags '" + ID->getString() + 1054 "': IDs have conflicting override values"); 1055 } 1056 continue; 1057 } else if (SrcBehaviorValue == Module::Override) { 1058 // Update the destination flag to that of the source. 1059 DstOp->replaceOperandWith(0, SrcBehavior); 1060 DstOp->replaceOperandWith(2, SrcOp->getOperand(2)); 1061 continue; 1062 } 1063 1064 // Diagnose inconsistent merge behavior types. 1065 if (SrcBehaviorValue != DstBehaviorValue) { 1066 HasErr |= emitError("linking module flags '" + ID->getString() + 1067 "': IDs have conflicting behaviors"); 1068 continue; 1069 } 1070 1071 // Perform the merge for standard behavior types. 1072 switch (SrcBehaviorValue) { 1073 case Module::Require: 1074 case Module::Override: assert(0 && "not possible"); break; 1075 case Module::Error: { 1076 // Emit an error if the values differ. 1077 if (SrcOp->getOperand(2) != DstOp->getOperand(2)) { 1078 HasErr |= emitError("linking module flags '" + ID->getString() + 1079 "': IDs have conflicting values"); 1080 } 1081 continue; 1082 } 1083 case Module::Warning: { 1084 // Emit a warning if the values differ. 1085 if (SrcOp->getOperand(2) != DstOp->getOperand(2)) { 1086 errs() << "WARNING: linking module flags '" << ID->getString() 1087 << "': IDs have conflicting values"; 1088 } 1089 continue; 1090 } 1091 case Module::Append: { 1092 MDNode *DstValue = cast<MDNode>(DstOp->getOperand(2)); 1093 MDNode *SrcValue = cast<MDNode>(SrcOp->getOperand(2)); 1094 unsigned NumOps = DstValue->getNumOperands() + SrcValue->getNumOperands(); 1095 Value **VP, **Values = VP = new Value*[NumOps]; 1096 for (unsigned i = 0, e = DstValue->getNumOperands(); i != e; ++i, ++VP) 1097 *VP = DstValue->getOperand(i); 1098 for (unsigned i = 0, e = SrcValue->getNumOperands(); i != e; ++i, ++VP) 1099 *VP = SrcValue->getOperand(i); 1100 DstOp->replaceOperandWith(2, MDNode::get(DstM->getContext(), 1101 ArrayRef<Value*>(Values, 1102 NumOps))); 1103 delete[] Values; 1104 break; 1105 } 1106 case Module::AppendUnique: { 1107 SmallSetVector<Value*, 16> Elts; 1108 MDNode *DstValue = cast<MDNode>(DstOp->getOperand(2)); 1109 MDNode *SrcValue = cast<MDNode>(SrcOp->getOperand(2)); 1110 for (unsigned i = 0, e = DstValue->getNumOperands(); i != e; ++i) 1111 Elts.insert(DstValue->getOperand(i)); 1112 for (unsigned i = 0, e = SrcValue->getNumOperands(); i != e; ++i) 1113 Elts.insert(SrcValue->getOperand(i)); 1114 DstOp->replaceOperandWith(2, MDNode::get(DstM->getContext(), 1115 ArrayRef<Value*>(Elts.begin(), 1116 Elts.end()))); 1117 break; 1118 } 1119 } 1120 } 1121 1122 // Check all of the requirements. 1123 for (unsigned I = 0, E = Requirements.size(); I != E; ++I) { 1124 MDNode *Requirement = Requirements[I]; 1125 MDString *Flag = cast<MDString>(Requirement->getOperand(0)); 1126 Value *ReqValue = Requirement->getOperand(1); 1127 1128 MDNode *Op = Flags[Flag]; 1129 if (!Op || Op->getOperand(2) != ReqValue) { 1130 HasErr |= emitError("linking module flags '" + Flag->getString() + 1131 "': does not have the required value"); 1132 continue; 1133 } 1134 } 1135 1136 return HasErr; 1137} 1138 1139bool ModuleLinker::run() { 1140 assert(DstM && "Null destination module"); 1141 assert(SrcM && "Null source module"); 1142 1143 // Inherit the target data from the source module if the destination module 1144 // doesn't have one already. 1145 if (DstM->getDataLayout().empty() && !SrcM->getDataLayout().empty()) 1146 DstM->setDataLayout(SrcM->getDataLayout()); 1147 1148 // Copy the target triple from the source to dest if the dest's is empty. 1149 if (DstM->getTargetTriple().empty() && !SrcM->getTargetTriple().empty()) 1150 DstM->setTargetTriple(SrcM->getTargetTriple()); 1151 1152 if (!SrcM->getDataLayout().empty() && !DstM->getDataLayout().empty() && 1153 SrcM->getDataLayout() != DstM->getDataLayout()) 1154 errs() << "WARNING: Linking two modules of different data layouts!\n"; 1155 if (!SrcM->getTargetTriple().empty() && 1156 DstM->getTargetTriple() != SrcM->getTargetTriple()) { 1157 errs() << "WARNING: Linking two modules of different target triples: "; 1158 if (!SrcM->getModuleIdentifier().empty()) 1159 errs() << SrcM->getModuleIdentifier() << ": "; 1160 errs() << "'" << SrcM->getTargetTriple() << "' and '" 1161 << DstM->getTargetTriple() << "'\n"; 1162 } 1163 1164 // Append the module inline asm string. 1165 if (!SrcM->getModuleInlineAsm().empty()) { 1166 if (DstM->getModuleInlineAsm().empty()) 1167 DstM->setModuleInlineAsm(SrcM->getModuleInlineAsm()); 1168 else 1169 DstM->setModuleInlineAsm(DstM->getModuleInlineAsm()+"\n"+ 1170 SrcM->getModuleInlineAsm()); 1171 } 1172 1173 // Loop over all of the linked values to compute type mappings. 1174 computeTypeMapping(); 1175 1176 // Insert all of the globals in src into the DstM module... without linking 1177 // initializers (which could refer to functions not yet mapped over). 1178 for (Module::global_iterator I = SrcM->global_begin(), 1179 E = SrcM->global_end(); I != E; ++I) 1180 if (linkGlobalProto(I)) 1181 return true; 1182 1183 // Link the functions together between the two modules, without doing function 1184 // bodies... this just adds external function prototypes to the DstM 1185 // function... We do this so that when we begin processing function bodies, 1186 // all of the global values that may be referenced are available in our 1187 // ValueMap. 1188 for (Module::iterator I = SrcM->begin(), E = SrcM->end(); I != E; ++I) 1189 if (linkFunctionProto(I)) 1190 return true; 1191 1192 // If there were any aliases, link them now. 1193 for (Module::alias_iterator I = SrcM->alias_begin(), 1194 E = SrcM->alias_end(); I != E; ++I) 1195 if (linkAliasProto(I)) 1196 return true; 1197 1198 for (unsigned i = 0, e = AppendingVars.size(); i != e; ++i) 1199 linkAppendingVarInit(AppendingVars[i]); 1200 1201 // Update the initializers in the DstM module now that all globals that may 1202 // be referenced are in DstM. 1203 linkGlobalInits(); 1204 1205 // Link in the function bodies that are defined in the source module into 1206 // DstM. 1207 for (Module::iterator SF = SrcM->begin(), E = SrcM->end(); SF != E; ++SF) { 1208 // Skip if not linking from source. 1209 if (DoNotLinkFromSource.count(SF)) continue; 1210 1211 // Skip if no body (function is external) or materialize. 1212 if (SF->isDeclaration()) { 1213 if (!SF->isMaterializable()) 1214 continue; 1215 if (SF->Materialize(&ErrorMsg)) 1216 return true; 1217 } 1218 1219 linkFunctionBody(cast<Function>(ValueMap[SF]), SF); 1220 SF->Dematerialize(); 1221 } 1222 1223 // Resolve all uses of aliases with aliasees. 1224 linkAliasBodies(); 1225 1226 // Remap all of the named MDNodes in Src into the DstM module. We do this 1227 // after linking GlobalValues so that MDNodes that reference GlobalValues 1228 // are properly remapped. 1229 linkNamedMDNodes(); 1230 1231 // Merge the module flags into the DstM module. 1232 if (linkModuleFlagsMetadata()) 1233 return true; 1234 1235 // Process vector of lazily linked in functions. 1236 bool LinkedInAnyFunctions; 1237 do { 1238 LinkedInAnyFunctions = false; 1239 1240 for(std::vector<Function*>::iterator I = LazilyLinkFunctions.begin(), 1241 E = LazilyLinkFunctions.end(); I != E; ++I) { 1242 if (!*I) 1243 continue; 1244 1245 Function *SF = *I; 1246 Function *DF = cast<Function>(ValueMap[SF]); 1247 1248 if (!DF->use_empty()) { 1249 1250 // Materialize if necessary. 1251 if (SF->isDeclaration()) { 1252 if (!SF->isMaterializable()) 1253 continue; 1254 if (SF->Materialize(&ErrorMsg)) 1255 return true; 1256 } 1257 1258 // Link in function body. 1259 linkFunctionBody(DF, SF); 1260 SF->Dematerialize(); 1261 1262 // "Remove" from vector by setting the element to 0. 1263 *I = 0; 1264 1265 // Set flag to indicate we may have more functions to lazily link in 1266 // since we linked in a function. 1267 LinkedInAnyFunctions = true; 1268 } 1269 } 1270 } while (LinkedInAnyFunctions); 1271 1272 // Remove any prototypes of functions that were not actually linked in. 1273 for(std::vector<Function*>::iterator I = LazilyLinkFunctions.begin(), 1274 E = LazilyLinkFunctions.end(); I != E; ++I) { 1275 if (!*I) 1276 continue; 1277 1278 Function *SF = *I; 1279 Function *DF = cast<Function>(ValueMap[SF]); 1280 if (DF->use_empty()) 1281 DF->eraseFromParent(); 1282 } 1283 1284 // Now that all of the types from the source are used, resolve any structs 1285 // copied over to the dest that didn't exist there. 1286 TypeMap.linkDefinedTypeBodies(); 1287 1288 return false; 1289} 1290 1291Linker::Linker(Module *M) : Composite(M) { 1292 TypeFinder StructTypes; 1293 StructTypes.run(*M, true); 1294 IdentifiedStructTypes.insert(StructTypes.begin(), StructTypes.end()); 1295} 1296 1297Linker::~Linker() { 1298} 1299 1300bool Linker::linkInModule(Module *Src, unsigned Mode, std::string *ErrorMsg) { 1301 ModuleLinker TheLinker(Composite, IdentifiedStructTypes, Src, Mode); 1302 if (TheLinker.run()) { 1303 if (ErrorMsg) 1304 *ErrorMsg = TheLinker.ErrorMsg; 1305 return true; 1306 } 1307 return false; 1308} 1309 1310//===----------------------------------------------------------------------===// 1311// LinkModules entrypoint. 1312//===----------------------------------------------------------------------===// 1313 1314/// LinkModules - This function links two modules together, with the resulting 1315/// Dest module modified to be the composite of the two input modules. If an 1316/// error occurs, true is returned and ErrorMsg (if not null) is set to indicate 1317/// the problem. Upon failure, the Dest module could be in a modified state, 1318/// and shouldn't be relied on to be consistent. 1319bool Linker::LinkModules(Module *Dest, Module *Src, unsigned Mode, 1320 std::string *ErrorMsg) { 1321 Linker L(Dest); 1322 return L.linkInModule(Src, Mode, ErrorMsg); 1323} 1324 1325//===----------------------------------------------------------------------===// 1326// C API. 1327//===----------------------------------------------------------------------===// 1328 1329LLVMBool LLVMLinkModules(LLVMModuleRef Dest, LLVMModuleRef Src, 1330 LLVMLinkerMode Mode, char **OutMessages) { 1331 std::string Messages; 1332 LLVMBool Result = Linker::LinkModules(unwrap(Dest), unwrap(Src), 1333 Mode, OutMessages? &Messages : 0); 1334 if (OutMessages) 1335 *OutMessages = strdup(Messages.c_str()); 1336 return Result; 1337} 1338