LinkModules.cpp revision 348e5e763e1297870878c5cb11aadfab2e8e5e7a
1//===- lib/Linker/LinkModules.cpp - Module Linker Implementation ----------===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file implements the LLVM module linker. 11// 12//===----------------------------------------------------------------------===// 13 14#include "llvm/Linker.h" 15#include "llvm/Constants.h" 16#include "llvm/DerivedTypes.h" 17#include "llvm/Instructions.h" 18#include "llvm/Module.h" 19#include "llvm/ADT/DenseSet.h" 20#include "llvm/ADT/Optional.h" 21#include "llvm/ADT/SetVector.h" 22#include "llvm/ADT/SmallPtrSet.h" 23#include "llvm/Support/raw_ostream.h" 24#include "llvm/Support/Path.h" 25#include "llvm/Transforms/Utils/Cloning.h" 26#include "llvm/Transforms/Utils/ValueMapper.h" 27using namespace llvm; 28 29//===----------------------------------------------------------------------===// 30// TypeMap implementation. 31//===----------------------------------------------------------------------===// 32 33namespace { 34class TypeMapTy : public ValueMapTypeRemapper { 35 /// MappedTypes - This is a mapping from a source type to a destination type 36 /// to use. 37 DenseMap<Type*, Type*> MappedTypes; 38 39 /// SpeculativeTypes - When checking to see if two subgraphs are isomorphic, 40 /// we speculatively add types to MappedTypes, but keep track of them here in 41 /// case we need to roll back. 42 SmallVector<Type*, 16> SpeculativeTypes; 43 44 /// SrcDefinitionsToResolve - This is a list of non-opaque structs in the 45 /// source module that are mapped to an opaque struct in the destination 46 /// module. 47 SmallVector<StructType*, 16> SrcDefinitionsToResolve; 48 49 /// DstResolvedOpaqueTypes - This is the set of opaque types in the 50 /// destination modules who are getting a body from the source module. 51 SmallPtrSet<StructType*, 16> DstResolvedOpaqueTypes; 52public: 53 54 /// addTypeMapping - Indicate that the specified type in the destination 55 /// module is conceptually equivalent to the specified type in the source 56 /// module. 57 void addTypeMapping(Type *DstTy, Type *SrcTy); 58 59 /// linkDefinedTypeBodies - Produce a body for an opaque type in the dest 60 /// module from a type definition in the source module. 61 void linkDefinedTypeBodies(); 62 63 /// get - Return the mapped type to use for the specified input type from the 64 /// source module. 65 Type *get(Type *SrcTy); 66 67 FunctionType *get(FunctionType *T) {return cast<FunctionType>(get((Type*)T));} 68 69private: 70 Type *getImpl(Type *T); 71 /// remapType - Implement the ValueMapTypeRemapper interface. 72 Type *remapType(Type *SrcTy) { 73 return get(SrcTy); 74 } 75 76 bool areTypesIsomorphic(Type *DstTy, Type *SrcTy); 77}; 78} 79 80void TypeMapTy::addTypeMapping(Type *DstTy, Type *SrcTy) { 81 Type *&Entry = MappedTypes[SrcTy]; 82 if (Entry) return; 83 84 if (DstTy == SrcTy) { 85 Entry = DstTy; 86 return; 87 } 88 89 // Check to see if these types are recursively isomorphic and establish a 90 // mapping between them if so. 91 if (!areTypesIsomorphic(DstTy, SrcTy)) { 92 // Oops, they aren't isomorphic. Just discard this request by rolling out 93 // any speculative mappings we've established. 94 for (unsigned i = 0, e = SpeculativeTypes.size(); i != e; ++i) 95 MappedTypes.erase(SpeculativeTypes[i]); 96 } 97 SpeculativeTypes.clear(); 98} 99 100/// areTypesIsomorphic - Recursively walk this pair of types, returning true 101/// if they are isomorphic, false if they are not. 102bool TypeMapTy::areTypesIsomorphic(Type *DstTy, Type *SrcTy) { 103 // Two types with differing kinds are clearly not isomorphic. 104 if (DstTy->getTypeID() != SrcTy->getTypeID()) return false; 105 106 // If we have an entry in the MappedTypes table, then we have our answer. 107 Type *&Entry = MappedTypes[SrcTy]; 108 if (Entry) 109 return Entry == DstTy; 110 111 // Two identical types are clearly isomorphic. Remember this 112 // non-speculatively. 113 if (DstTy == SrcTy) { 114 Entry = DstTy; 115 return true; 116 } 117 118 // Okay, we have two types with identical kinds that we haven't seen before. 119 120 // If this is an opaque struct type, special case it. 121 if (StructType *SSTy = dyn_cast<StructType>(SrcTy)) { 122 // Mapping an opaque type to any struct, just keep the dest struct. 123 if (SSTy->isOpaque()) { 124 Entry = DstTy; 125 SpeculativeTypes.push_back(SrcTy); 126 return true; 127 } 128 129 // Mapping a non-opaque source type to an opaque dest. If this is the first 130 // type that we're mapping onto this destination type then we succeed. Keep 131 // the dest, but fill it in later. This doesn't need to be speculative. If 132 // this is the second (different) type that we're trying to map onto the 133 // same opaque type then we fail. 134 if (cast<StructType>(DstTy)->isOpaque()) { 135 // We can only map one source type onto the opaque destination type. 136 if (!DstResolvedOpaqueTypes.insert(cast<StructType>(DstTy))) 137 return false; 138 SrcDefinitionsToResolve.push_back(SSTy); 139 Entry = DstTy; 140 return true; 141 } 142 } 143 144 // If the number of subtypes disagree between the two types, then we fail. 145 if (SrcTy->getNumContainedTypes() != DstTy->getNumContainedTypes()) 146 return false; 147 148 // Fail if any of the extra properties (e.g. array size) of the type disagree. 149 if (isa<IntegerType>(DstTy)) 150 return false; // bitwidth disagrees. 151 if (PointerType *PT = dyn_cast<PointerType>(DstTy)) { 152 if (PT->getAddressSpace() != cast<PointerType>(SrcTy)->getAddressSpace()) 153 return false; 154 155 } else if (FunctionType *FT = dyn_cast<FunctionType>(DstTy)) { 156 if (FT->isVarArg() != cast<FunctionType>(SrcTy)->isVarArg()) 157 return false; 158 } else if (StructType *DSTy = dyn_cast<StructType>(DstTy)) { 159 StructType *SSTy = cast<StructType>(SrcTy); 160 if (DSTy->isLiteral() != SSTy->isLiteral() || 161 DSTy->isPacked() != SSTy->isPacked()) 162 return false; 163 } else if (ArrayType *DATy = dyn_cast<ArrayType>(DstTy)) { 164 if (DATy->getNumElements() != cast<ArrayType>(SrcTy)->getNumElements()) 165 return false; 166 } else if (VectorType *DVTy = dyn_cast<VectorType>(DstTy)) { 167 if (DVTy->getNumElements() != cast<ArrayType>(SrcTy)->getNumElements()) 168 return false; 169 } 170 171 // Otherwise, we speculate that these two types will line up and recursively 172 // check the subelements. 173 Entry = DstTy; 174 SpeculativeTypes.push_back(SrcTy); 175 176 for (unsigned i = 0, e = SrcTy->getNumContainedTypes(); i != e; ++i) 177 if (!areTypesIsomorphic(DstTy->getContainedType(i), 178 SrcTy->getContainedType(i))) 179 return false; 180 181 // If everything seems to have lined up, then everything is great. 182 return true; 183} 184 185/// linkDefinedTypeBodies - Produce a body for an opaque type in the dest 186/// module from a type definition in the source module. 187void TypeMapTy::linkDefinedTypeBodies() { 188 SmallVector<Type*, 16> Elements; 189 SmallString<16> TmpName; 190 191 // Note that processing entries in this loop (calling 'get') can add new 192 // entries to the SrcDefinitionsToResolve vector. 193 while (!SrcDefinitionsToResolve.empty()) { 194 StructType *SrcSTy = SrcDefinitionsToResolve.pop_back_val(); 195 StructType *DstSTy = cast<StructType>(MappedTypes[SrcSTy]); 196 197 // TypeMap is a many-to-one mapping, if there were multiple types that 198 // provide a body for DstSTy then previous iterations of this loop may have 199 // already handled it. Just ignore this case. 200 if (!DstSTy->isOpaque()) continue; 201 assert(!SrcSTy->isOpaque() && "Not resolving a definition?"); 202 203 // Map the body of the source type over to a new body for the dest type. 204 Elements.resize(SrcSTy->getNumElements()); 205 for (unsigned i = 0, e = Elements.size(); i != e; ++i) 206 Elements[i] = getImpl(SrcSTy->getElementType(i)); 207 208 DstSTy->setBody(Elements, SrcSTy->isPacked()); 209 210 // If DstSTy has no name or has a longer name than STy, then viciously steal 211 // STy's name. 212 if (!SrcSTy->hasName()) continue; 213 StringRef SrcName = SrcSTy->getName(); 214 215 if (!DstSTy->hasName() || DstSTy->getName().size() > SrcName.size()) { 216 TmpName.insert(TmpName.end(), SrcName.begin(), SrcName.end()); 217 SrcSTy->setName(""); 218 DstSTy->setName(TmpName.str()); 219 TmpName.clear(); 220 } 221 } 222 223 DstResolvedOpaqueTypes.clear(); 224} 225 226 227/// get - Return the mapped type to use for the specified input type from the 228/// source module. 229Type *TypeMapTy::get(Type *Ty) { 230 Type *Result = getImpl(Ty); 231 232 // If this caused a reference to any struct type, resolve it before returning. 233 if (!SrcDefinitionsToResolve.empty()) 234 linkDefinedTypeBodies(); 235 return Result; 236} 237 238/// getImpl - This is the recursive version of get(). 239Type *TypeMapTy::getImpl(Type *Ty) { 240 // If we already have an entry for this type, return it. 241 Type **Entry = &MappedTypes[Ty]; 242 if (*Entry) return *Entry; 243 244 // If this is not a named struct type, then just map all of the elements and 245 // then rebuild the type from inside out. 246 if (!isa<StructType>(Ty) || cast<StructType>(Ty)->isLiteral()) { 247 // If there are no element types to map, then the type is itself. This is 248 // true for the anonymous {} struct, things like 'float', integers, etc. 249 if (Ty->getNumContainedTypes() == 0) 250 return *Entry = Ty; 251 252 // Remap all of the elements, keeping track of whether any of them change. 253 bool AnyChange = false; 254 SmallVector<Type*, 4> ElementTypes; 255 ElementTypes.resize(Ty->getNumContainedTypes()); 256 for (unsigned i = 0, e = Ty->getNumContainedTypes(); i != e; ++i) { 257 ElementTypes[i] = getImpl(Ty->getContainedType(i)); 258 AnyChange |= ElementTypes[i] != Ty->getContainedType(i); 259 } 260 261 // If we found our type while recursively processing stuff, just use it. 262 Entry = &MappedTypes[Ty]; 263 if (*Entry) return *Entry; 264 265 // If all of the element types mapped directly over, then the type is usable 266 // as-is. 267 if (!AnyChange) 268 return *Entry = Ty; 269 270 // Otherwise, rebuild a modified type. 271 switch (Ty->getTypeID()) { 272 default: llvm_unreachable("unknown derived type to remap"); 273 case Type::ArrayTyID: 274 return *Entry = ArrayType::get(ElementTypes[0], 275 cast<ArrayType>(Ty)->getNumElements()); 276 case Type::VectorTyID: 277 return *Entry = VectorType::get(ElementTypes[0], 278 cast<VectorType>(Ty)->getNumElements()); 279 case Type::PointerTyID: 280 return *Entry = PointerType::get(ElementTypes[0], 281 cast<PointerType>(Ty)->getAddressSpace()); 282 case Type::FunctionTyID: 283 return *Entry = FunctionType::get(ElementTypes[0], 284 makeArrayRef(ElementTypes).slice(1), 285 cast<FunctionType>(Ty)->isVarArg()); 286 case Type::StructTyID: 287 // Note that this is only reached for anonymous structs. 288 return *Entry = StructType::get(Ty->getContext(), ElementTypes, 289 cast<StructType>(Ty)->isPacked()); 290 } 291 } 292 293 // Otherwise, this is an unmapped named struct. If the struct can be directly 294 // mapped over, just use it as-is. This happens in a case when the linked-in 295 // module has something like: 296 // %T = type {%T*, i32} 297 // @GV = global %T* null 298 // where T does not exist at all in the destination module. 299 // 300 // The other case we watch for is when the type is not in the destination 301 // module, but that it has to be rebuilt because it refers to something that 302 // is already mapped. For example, if the destination module has: 303 // %A = type { i32 } 304 // and the source module has something like 305 // %A' = type { i32 } 306 // %B = type { %A'* } 307 // @GV = global %B* null 308 // then we want to create a new type: "%B = type { %A*}" and have it take the 309 // pristine "%B" name from the source module. 310 // 311 // To determine which case this is, we have to recursively walk the type graph 312 // speculating that we'll be able to reuse it unmodified. Only if this is 313 // safe would we map the entire thing over. Because this is an optimization, 314 // and is not required for the prettiness of the linked module, we just skip 315 // it and always rebuild a type here. 316 StructType *STy = cast<StructType>(Ty); 317 318 // If the type is opaque, we can just use it directly. 319 if (STy->isOpaque()) 320 return *Entry = STy; 321 322 // Otherwise we create a new type and resolve its body later. This will be 323 // resolved by the top level of get(). 324 SrcDefinitionsToResolve.push_back(STy); 325 StructType *DTy = StructType::create(STy->getContext()); 326 DstResolvedOpaqueTypes.insert(DTy); 327 return *Entry = DTy; 328} 329 330 331 332//===----------------------------------------------------------------------===// 333// ModuleLinker implementation. 334//===----------------------------------------------------------------------===// 335 336namespace { 337 /// ModuleLinker - This is an implementation class for the LinkModules 338 /// function, which is the entrypoint for this file. 339 class ModuleLinker { 340 Module *DstM, *SrcM; 341 342 TypeMapTy TypeMap; 343 344 /// ValueMap - Mapping of values from what they used to be in Src, to what 345 /// they are now in DstM. ValueToValueMapTy is a ValueMap, which involves 346 /// some overhead due to the use of Value handles which the Linker doesn't 347 /// actually need, but this allows us to reuse the ValueMapper code. 348 ValueToValueMapTy ValueMap; 349 350 struct AppendingVarInfo { 351 GlobalVariable *NewGV; // New aggregate global in dest module. 352 Constant *DstInit; // Old initializer from dest module. 353 Constant *SrcInit; // Old initializer from src module. 354 }; 355 356 std::vector<AppendingVarInfo> AppendingVars; 357 358 unsigned Mode; // Mode to treat source module. 359 360 // Set of items not to link in from source. 361 SmallPtrSet<const Value*, 16> DoNotLinkFromSource; 362 363 // Vector of functions to lazily link in. 364 std::vector<Function*> LazilyLinkFunctions; 365 366 public: 367 std::string ErrorMsg; 368 369 ModuleLinker(Module *dstM, Module *srcM, unsigned mode) 370 : DstM(dstM), SrcM(srcM), Mode(mode) { } 371 372 bool run(); 373 374 private: 375 /// emitError - Helper method for setting a message and returning an error 376 /// code. 377 bool emitError(const Twine &Message) { 378 ErrorMsg = Message.str(); 379 return true; 380 } 381 382 /// getLinkageResult - This analyzes the two global values and determines 383 /// what the result will look like in the destination module. 384 bool getLinkageResult(GlobalValue *Dest, const GlobalValue *Src, 385 GlobalValue::LinkageTypes <, 386 GlobalValue::VisibilityTypes &Vis, 387 bool &LinkFromSrc); 388 389 /// getLinkedToGlobal - Given a global in the source module, return the 390 /// global in the destination module that is being linked to, if any. 391 GlobalValue *getLinkedToGlobal(GlobalValue *SrcGV) { 392 // If the source has no name it can't link. If it has local linkage, 393 // there is no name match-up going on. 394 if (!SrcGV->hasName() || SrcGV->hasLocalLinkage()) 395 return 0; 396 397 // Otherwise see if we have a match in the destination module's symtab. 398 GlobalValue *DGV = DstM->getNamedValue(SrcGV->getName()); 399 if (DGV == 0) return 0; 400 401 // If we found a global with the same name in the dest module, but it has 402 // internal linkage, we are really not doing any linkage here. 403 if (DGV->hasLocalLinkage()) 404 return 0; 405 406 // Otherwise, we do in fact link to the destination global. 407 return DGV; 408 } 409 410 void computeTypeMapping(); 411 bool categorizeModuleFlagNodes(const NamedMDNode *ModFlags, 412 DenseMap<MDString*, MDNode*> &ErrorNode, 413 DenseMap<MDString*, MDNode*> &WarningNode, 414 DenseMap<MDString*, MDNode*> &OverrideNode, 415 DenseMap<MDString*, 416 SmallSetVector<MDNode*, 8> > &RequireNodes, 417 SmallSetVector<MDString*, 16> &SeenIDs); 418 419 bool linkAppendingVarProto(GlobalVariable *DstGV, GlobalVariable *SrcGV); 420 bool linkGlobalProto(GlobalVariable *SrcGV); 421 bool linkFunctionProto(Function *SrcF); 422 bool linkAliasProto(GlobalAlias *SrcA); 423 bool linkModuleFlagsMetadata(); 424 425 void linkAppendingVarInit(const AppendingVarInfo &AVI); 426 void linkGlobalInits(); 427 void linkFunctionBody(Function *Dst, Function *Src); 428 void linkAliasBodies(); 429 void linkNamedMDNodes(); 430 }; 431} 432 433 434 435/// forceRenaming - The LLVM SymbolTable class autorenames globals that conflict 436/// in the symbol table. This is good for all clients except for us. Go 437/// through the trouble to force this back. 438static void forceRenaming(GlobalValue *GV, StringRef Name) { 439 // If the global doesn't force its name or if it already has the right name, 440 // there is nothing for us to do. 441 if (GV->hasLocalLinkage() || GV->getName() == Name) 442 return; 443 444 Module *M = GV->getParent(); 445 446 // If there is a conflict, rename the conflict. 447 if (GlobalValue *ConflictGV = M->getNamedValue(Name)) { 448 GV->takeName(ConflictGV); 449 ConflictGV->setName(Name); // This will cause ConflictGV to get renamed 450 assert(ConflictGV->getName() != Name && "forceRenaming didn't work"); 451 } else { 452 GV->setName(Name); // Force the name back 453 } 454} 455 456/// CopyGVAttributes - copy additional attributes (those not needed to construct 457/// a GlobalValue) from the SrcGV to the DestGV. 458static void CopyGVAttributes(GlobalValue *DestGV, const GlobalValue *SrcGV) { 459 // Use the maximum alignment, rather than just copying the alignment of SrcGV. 460 unsigned Alignment = std::max(DestGV->getAlignment(), SrcGV->getAlignment()); 461 DestGV->copyAttributesFrom(SrcGV); 462 DestGV->setAlignment(Alignment); 463 464 forceRenaming(DestGV, SrcGV->getName()); 465} 466 467static bool isLessConstraining(GlobalValue::VisibilityTypes a, 468 GlobalValue::VisibilityTypes b) { 469 if (a == GlobalValue::HiddenVisibility) 470 return false; 471 if (b == GlobalValue::HiddenVisibility) 472 return true; 473 if (a == GlobalValue::ProtectedVisibility) 474 return false; 475 if (b == GlobalValue::ProtectedVisibility) 476 return true; 477 return false; 478} 479 480/// getLinkageResult - This analyzes the two global values and determines what 481/// the result will look like in the destination module. In particular, it 482/// computes the resultant linkage type and visibility, computes whether the 483/// global in the source should be copied over to the destination (replacing 484/// the existing one), and computes whether this linkage is an error or not. 485bool ModuleLinker::getLinkageResult(GlobalValue *Dest, const GlobalValue *Src, 486 GlobalValue::LinkageTypes <, 487 GlobalValue::VisibilityTypes &Vis, 488 bool &LinkFromSrc) { 489 assert(Dest && "Must have two globals being queried"); 490 assert(!Src->hasLocalLinkage() && 491 "If Src has internal linkage, Dest shouldn't be set!"); 492 493 bool SrcIsDeclaration = Src->isDeclaration() && !Src->isMaterializable(); 494 bool DestIsDeclaration = Dest->isDeclaration(); 495 496 if (SrcIsDeclaration) { 497 // If Src is external or if both Src & Dest are external.. Just link the 498 // external globals, we aren't adding anything. 499 if (Src->hasDLLImportLinkage()) { 500 // If one of GVs has DLLImport linkage, result should be dllimport'ed. 501 if (DestIsDeclaration) { 502 LinkFromSrc = true; 503 LT = Src->getLinkage(); 504 } 505 } else if (Dest->hasExternalWeakLinkage()) { 506 // If the Dest is weak, use the source linkage. 507 LinkFromSrc = true; 508 LT = Src->getLinkage(); 509 } else { 510 LinkFromSrc = false; 511 LT = Dest->getLinkage(); 512 } 513 } else if (DestIsDeclaration && !Dest->hasDLLImportLinkage()) { 514 // If Dest is external but Src is not: 515 LinkFromSrc = true; 516 LT = Src->getLinkage(); 517 } else if (Src->isWeakForLinker()) { 518 // At this point we know that Dest has LinkOnce, External*, Weak, Common, 519 // or DLL* linkage. 520 if (Dest->hasExternalWeakLinkage() || 521 Dest->hasAvailableExternallyLinkage() || 522 (Dest->hasLinkOnceLinkage() && 523 (Src->hasWeakLinkage() || Src->hasCommonLinkage()))) { 524 LinkFromSrc = true; 525 LT = Src->getLinkage(); 526 } else { 527 LinkFromSrc = false; 528 LT = Dest->getLinkage(); 529 } 530 } else if (Dest->isWeakForLinker()) { 531 // At this point we know that Src has External* or DLL* linkage. 532 if (Src->hasExternalWeakLinkage()) { 533 LinkFromSrc = false; 534 LT = Dest->getLinkage(); 535 } else { 536 LinkFromSrc = true; 537 LT = GlobalValue::ExternalLinkage; 538 } 539 } else { 540 assert((Dest->hasExternalLinkage() || Dest->hasDLLImportLinkage() || 541 Dest->hasDLLExportLinkage() || Dest->hasExternalWeakLinkage()) && 542 (Src->hasExternalLinkage() || Src->hasDLLImportLinkage() || 543 Src->hasDLLExportLinkage() || Src->hasExternalWeakLinkage()) && 544 "Unexpected linkage type!"); 545 return emitError("Linking globals named '" + Src->getName() + 546 "': symbol multiply defined!"); 547 } 548 549 // Compute the visibility. We follow the rules in the System V Application 550 // Binary Interface. 551 Vis = isLessConstraining(Src->getVisibility(), Dest->getVisibility()) ? 552 Dest->getVisibility() : Src->getVisibility(); 553 return false; 554} 555 556/// computeTypeMapping - Loop over all of the linked values to compute type 557/// mappings. For example, if we link "extern Foo *x" and "Foo *x = NULL", then 558/// we have two struct types 'Foo' but one got renamed when the module was 559/// loaded into the same LLVMContext. 560void ModuleLinker::computeTypeMapping() { 561 // Incorporate globals. 562 for (Module::global_iterator I = SrcM->global_begin(), 563 E = SrcM->global_end(); I != E; ++I) { 564 GlobalValue *DGV = getLinkedToGlobal(I); 565 if (DGV == 0) continue; 566 567 if (!DGV->hasAppendingLinkage() || !I->hasAppendingLinkage()) { 568 TypeMap.addTypeMapping(DGV->getType(), I->getType()); 569 continue; 570 } 571 572 // Unify the element type of appending arrays. 573 ArrayType *DAT = cast<ArrayType>(DGV->getType()->getElementType()); 574 ArrayType *SAT = cast<ArrayType>(I->getType()->getElementType()); 575 TypeMap.addTypeMapping(DAT->getElementType(), SAT->getElementType()); 576 } 577 578 // Incorporate functions. 579 for (Module::iterator I = SrcM->begin(), E = SrcM->end(); I != E; ++I) { 580 if (GlobalValue *DGV = getLinkedToGlobal(I)) 581 TypeMap.addTypeMapping(DGV->getType(), I->getType()); 582 } 583 584 // Incorporate types by name, scanning all the types in the source module. 585 // At this point, the destination module may have a type "%foo = { i32 }" for 586 // example. When the source module got loaded into the same LLVMContext, if 587 // it had the same type, it would have been renamed to "%foo.42 = { i32 }". 588 // Though it isn't required for correctness, attempt to link these up to clean 589 // up the IR. 590 std::vector<StructType*> SrcStructTypes; 591 SrcM->findUsedStructTypes(SrcStructTypes); 592 593 SmallPtrSet<StructType*, 32> SrcStructTypesSet(SrcStructTypes.begin(), 594 SrcStructTypes.end()); 595 596 for (unsigned i = 0, e = SrcStructTypes.size(); i != e; ++i) { 597 StructType *ST = SrcStructTypes[i]; 598 if (!ST->hasName()) continue; 599 600 // Check to see if there is a dot in the name followed by a digit. 601 size_t DotPos = ST->getName().rfind('.'); 602 if (DotPos == 0 || DotPos == StringRef::npos || 603 ST->getName().back() == '.' || !isdigit(ST->getName()[DotPos+1])) 604 continue; 605 606 // Check to see if the destination module has a struct with the prefix name. 607 if (StructType *DST = DstM->getTypeByName(ST->getName().substr(0, DotPos))) 608 // Don't use it if this actually came from the source module. They're in 609 // the same LLVMContext after all. 610 if (!SrcStructTypesSet.count(DST)) 611 TypeMap.addTypeMapping(DST, ST); 612 } 613 614 // Don't bother incorporating aliases, they aren't generally typed well. 615 616 // Now that we have discovered all of the type equivalences, get a body for 617 // any 'opaque' types in the dest module that are now resolved. 618 TypeMap.linkDefinedTypeBodies(); 619} 620 621/// linkAppendingVarProto - If there were any appending global variables, link 622/// them together now. Return true on error. 623bool ModuleLinker::linkAppendingVarProto(GlobalVariable *DstGV, 624 GlobalVariable *SrcGV) { 625 626 if (!SrcGV->hasAppendingLinkage() || !DstGV->hasAppendingLinkage()) 627 return emitError("Linking globals named '" + SrcGV->getName() + 628 "': can only link appending global with another appending global!"); 629 630 ArrayType *DstTy = cast<ArrayType>(DstGV->getType()->getElementType()); 631 ArrayType *SrcTy = 632 cast<ArrayType>(TypeMap.get(SrcGV->getType()->getElementType())); 633 Type *EltTy = DstTy->getElementType(); 634 635 // Check to see that they two arrays agree on type. 636 if (EltTy != SrcTy->getElementType()) 637 return emitError("Appending variables with different element types!"); 638 if (DstGV->isConstant() != SrcGV->isConstant()) 639 return emitError("Appending variables linked with different const'ness!"); 640 641 if (DstGV->getAlignment() != SrcGV->getAlignment()) 642 return emitError( 643 "Appending variables with different alignment need to be linked!"); 644 645 if (DstGV->getVisibility() != SrcGV->getVisibility()) 646 return emitError( 647 "Appending variables with different visibility need to be linked!"); 648 649 if (DstGV->getSection() != SrcGV->getSection()) 650 return emitError( 651 "Appending variables with different section name need to be linked!"); 652 653 uint64_t NewSize = DstTy->getNumElements() + SrcTy->getNumElements(); 654 ArrayType *NewType = ArrayType::get(EltTy, NewSize); 655 656 // Create the new global variable. 657 GlobalVariable *NG = 658 new GlobalVariable(*DstGV->getParent(), NewType, SrcGV->isConstant(), 659 DstGV->getLinkage(), /*init*/0, /*name*/"", DstGV, 660 DstGV->isThreadLocal(), 661 DstGV->getType()->getAddressSpace()); 662 663 // Propagate alignment, visibility and section info. 664 CopyGVAttributes(NG, DstGV); 665 666 AppendingVarInfo AVI; 667 AVI.NewGV = NG; 668 AVI.DstInit = DstGV->getInitializer(); 669 AVI.SrcInit = SrcGV->getInitializer(); 670 AppendingVars.push_back(AVI); 671 672 // Replace any uses of the two global variables with uses of the new 673 // global. 674 ValueMap[SrcGV] = ConstantExpr::getBitCast(NG, TypeMap.get(SrcGV->getType())); 675 676 DstGV->replaceAllUsesWith(ConstantExpr::getBitCast(NG, DstGV->getType())); 677 DstGV->eraseFromParent(); 678 679 // Track the source variable so we don't try to link it. 680 DoNotLinkFromSource.insert(SrcGV); 681 682 return false; 683} 684 685/// linkGlobalProto - Loop through the global variables in the src module and 686/// merge them into the dest module. 687bool ModuleLinker::linkGlobalProto(GlobalVariable *SGV) { 688 GlobalValue *DGV = getLinkedToGlobal(SGV); 689 llvm::Optional<GlobalValue::VisibilityTypes> NewVisibility; 690 691 if (DGV) { 692 // Concatenation of appending linkage variables is magic and handled later. 693 if (DGV->hasAppendingLinkage() || SGV->hasAppendingLinkage()) 694 return linkAppendingVarProto(cast<GlobalVariable>(DGV), SGV); 695 696 // Determine whether linkage of these two globals follows the source 697 // module's definition or the destination module's definition. 698 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; 699 GlobalValue::VisibilityTypes NV; 700 bool LinkFromSrc = false; 701 if (getLinkageResult(DGV, SGV, NewLinkage, NV, LinkFromSrc)) 702 return true; 703 NewVisibility = NV; 704 705 // If we're not linking from the source, then keep the definition that we 706 // have. 707 if (!LinkFromSrc) { 708 // Special case for const propagation. 709 if (GlobalVariable *DGVar = dyn_cast<GlobalVariable>(DGV)) 710 if (DGVar->isDeclaration() && SGV->isConstant() && !DGVar->isConstant()) 711 DGVar->setConstant(true); 712 713 // Set calculated linkage and visibility. 714 DGV->setLinkage(NewLinkage); 715 DGV->setVisibility(*NewVisibility); 716 717 // Make sure to remember this mapping. 718 ValueMap[SGV] = ConstantExpr::getBitCast(DGV,TypeMap.get(SGV->getType())); 719 720 // Track the source global so that we don't attempt to copy it over when 721 // processing global initializers. 722 DoNotLinkFromSource.insert(SGV); 723 724 return false; 725 } 726 } 727 728 // No linking to be performed or linking from the source: simply create an 729 // identical version of the symbol over in the dest module... the 730 // initializer will be filled in later by LinkGlobalInits. 731 GlobalVariable *NewDGV = 732 new GlobalVariable(*DstM, TypeMap.get(SGV->getType()->getElementType()), 733 SGV->isConstant(), SGV->getLinkage(), /*init*/0, 734 SGV->getName(), /*insertbefore*/0, 735 SGV->isThreadLocal(), 736 SGV->getType()->getAddressSpace()); 737 // Propagate alignment, visibility and section info. 738 CopyGVAttributes(NewDGV, SGV); 739 if (NewVisibility) 740 NewDGV->setVisibility(*NewVisibility); 741 742 if (DGV) { 743 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDGV, DGV->getType())); 744 DGV->eraseFromParent(); 745 } 746 747 // Make sure to remember this mapping. 748 ValueMap[SGV] = NewDGV; 749 return false; 750} 751 752/// linkFunctionProto - Link the function in the source module into the 753/// destination module if needed, setting up mapping information. 754bool ModuleLinker::linkFunctionProto(Function *SF) { 755 GlobalValue *DGV = getLinkedToGlobal(SF); 756 llvm::Optional<GlobalValue::VisibilityTypes> NewVisibility; 757 758 if (DGV) { 759 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; 760 bool LinkFromSrc = false; 761 GlobalValue::VisibilityTypes NV; 762 if (getLinkageResult(DGV, SF, NewLinkage, NV, LinkFromSrc)) 763 return true; 764 NewVisibility = NV; 765 766 if (!LinkFromSrc) { 767 // Set calculated linkage 768 DGV->setLinkage(NewLinkage); 769 DGV->setVisibility(*NewVisibility); 770 771 // Make sure to remember this mapping. 772 ValueMap[SF] = ConstantExpr::getBitCast(DGV, TypeMap.get(SF->getType())); 773 774 // Track the function from the source module so we don't attempt to remap 775 // it. 776 DoNotLinkFromSource.insert(SF); 777 778 return false; 779 } 780 } 781 782 // If there is no linkage to be performed or we are linking from the source, 783 // bring SF over. 784 Function *NewDF = Function::Create(TypeMap.get(SF->getFunctionType()), 785 SF->getLinkage(), SF->getName(), DstM); 786 CopyGVAttributes(NewDF, SF); 787 if (NewVisibility) 788 NewDF->setVisibility(*NewVisibility); 789 790 if (DGV) { 791 // Any uses of DF need to change to NewDF, with cast. 792 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDF, DGV->getType())); 793 DGV->eraseFromParent(); 794 } else { 795 // Internal, LO_ODR, or LO linkage - stick in set to ignore and lazily link. 796 if (SF->hasLocalLinkage() || SF->hasLinkOnceLinkage() || 797 SF->hasAvailableExternallyLinkage()) { 798 DoNotLinkFromSource.insert(SF); 799 LazilyLinkFunctions.push_back(SF); 800 } 801 } 802 803 ValueMap[SF] = NewDF; 804 return false; 805} 806 807/// LinkAliasProto - Set up prototypes for any aliases that come over from the 808/// source module. 809bool ModuleLinker::linkAliasProto(GlobalAlias *SGA) { 810 GlobalValue *DGV = getLinkedToGlobal(SGA); 811 llvm::Optional<GlobalValue::VisibilityTypes> NewVisibility; 812 813 if (DGV) { 814 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; 815 GlobalValue::VisibilityTypes NV; 816 bool LinkFromSrc = false; 817 if (getLinkageResult(DGV, SGA, NewLinkage, NV, LinkFromSrc)) 818 return true; 819 NewVisibility = NV; 820 821 if (!LinkFromSrc) { 822 // Set calculated linkage. 823 DGV->setLinkage(NewLinkage); 824 DGV->setVisibility(*NewVisibility); 825 826 // Make sure to remember this mapping. 827 ValueMap[SGA] = ConstantExpr::getBitCast(DGV,TypeMap.get(SGA->getType())); 828 829 // Track the alias from the source module so we don't attempt to remap it. 830 DoNotLinkFromSource.insert(SGA); 831 832 return false; 833 } 834 } 835 836 // If there is no linkage to be performed or we're linking from the source, 837 // bring over SGA. 838 GlobalAlias *NewDA = new GlobalAlias(TypeMap.get(SGA->getType()), 839 SGA->getLinkage(), SGA->getName(), 840 /*aliasee*/0, DstM); 841 CopyGVAttributes(NewDA, SGA); 842 if (NewVisibility) 843 NewDA->setVisibility(*NewVisibility); 844 845 if (DGV) { 846 // Any uses of DGV need to change to NewDA, with cast. 847 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDA, DGV->getType())); 848 DGV->eraseFromParent(); 849 } 850 851 ValueMap[SGA] = NewDA; 852 return false; 853} 854 855static void getArrayElements(Constant *C, SmallVectorImpl<Constant*> &Dest) { 856 unsigned NumElements = cast<ArrayType>(C->getType())->getNumElements(); 857 858 for (unsigned i = 0; i != NumElements; ++i) 859 Dest.push_back(C->getAggregateElement(i)); 860} 861 862void ModuleLinker::linkAppendingVarInit(const AppendingVarInfo &AVI) { 863 // Merge the initializer. 864 SmallVector<Constant*, 16> Elements; 865 getArrayElements(AVI.DstInit, Elements); 866 867 Constant *SrcInit = MapValue(AVI.SrcInit, ValueMap, RF_None, &TypeMap); 868 getArrayElements(SrcInit, Elements); 869 870 ArrayType *NewType = cast<ArrayType>(AVI.NewGV->getType()->getElementType()); 871 AVI.NewGV->setInitializer(ConstantArray::get(NewType, Elements)); 872} 873 874 875// linkGlobalInits - Update the initializers in the Dest module now that all 876// globals that may be referenced are in Dest. 877void ModuleLinker::linkGlobalInits() { 878 // Loop over all of the globals in the src module, mapping them over as we go 879 for (Module::const_global_iterator I = SrcM->global_begin(), 880 E = SrcM->global_end(); I != E; ++I) { 881 882 // Only process initialized GV's or ones not already in dest. 883 if (!I->hasInitializer() || DoNotLinkFromSource.count(I)) continue; 884 885 // Grab destination global variable. 886 GlobalVariable *DGV = cast<GlobalVariable>(ValueMap[I]); 887 // Figure out what the initializer looks like in the dest module. 888 DGV->setInitializer(MapValue(I->getInitializer(), ValueMap, 889 RF_None, &TypeMap)); 890 } 891} 892 893// linkFunctionBody - Copy the source function over into the dest function and 894// fix up references to values. At this point we know that Dest is an external 895// function, and that Src is not. 896void ModuleLinker::linkFunctionBody(Function *Dst, Function *Src) { 897 assert(Src && Dst && Dst->isDeclaration() && !Src->isDeclaration()); 898 899 // Go through and convert function arguments over, remembering the mapping. 900 Function::arg_iterator DI = Dst->arg_begin(); 901 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end(); 902 I != E; ++I, ++DI) { 903 DI->setName(I->getName()); // Copy the name over. 904 905 // Add a mapping to our mapping. 906 ValueMap[I] = DI; 907 } 908 909 if (Mode == Linker::DestroySource) { 910 // Splice the body of the source function into the dest function. 911 Dst->getBasicBlockList().splice(Dst->end(), Src->getBasicBlockList()); 912 913 // At this point, all of the instructions and values of the function are now 914 // copied over. The only problem is that they are still referencing values in 915 // the Source function as operands. Loop through all of the operands of the 916 // functions and patch them up to point to the local versions. 917 for (Function::iterator BB = Dst->begin(), BE = Dst->end(); BB != BE; ++BB) 918 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) 919 RemapInstruction(I, ValueMap, RF_IgnoreMissingEntries, &TypeMap); 920 921 } else { 922 // Clone the body of the function into the dest function. 923 SmallVector<ReturnInst*, 8> Returns; // Ignore returns. 924 CloneFunctionInto(Dst, Src, ValueMap, false, Returns, "", NULL, &TypeMap); 925 } 926 927 // There is no need to map the arguments anymore. 928 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end(); 929 I != E; ++I) 930 ValueMap.erase(I); 931 932} 933 934 935void ModuleLinker::linkAliasBodies() { 936 for (Module::alias_iterator I = SrcM->alias_begin(), E = SrcM->alias_end(); 937 I != E; ++I) { 938 if (DoNotLinkFromSource.count(I)) 939 continue; 940 if (Constant *Aliasee = I->getAliasee()) { 941 GlobalAlias *DA = cast<GlobalAlias>(ValueMap[I]); 942 DA->setAliasee(MapValue(Aliasee, ValueMap, RF_None, &TypeMap)); 943 } 944 } 945} 946 947/// linkNamedMDNodes - Insert all of the named mdnodes in Src into the Dest 948/// module. 949void ModuleLinker::linkNamedMDNodes() { 950 const NamedMDNode *SrcModFlags = SrcM->getModuleFlagsMetadata(); 951 for (Module::const_named_metadata_iterator I = SrcM->named_metadata_begin(), 952 E = SrcM->named_metadata_end(); I != E; ++I) { 953 // Don't link module flags here. Do them separately. 954 if (&*I == SrcModFlags) continue; 955 NamedMDNode *DestNMD = DstM->getOrInsertNamedMetadata(I->getName()); 956 // Add Src elements into Dest node. 957 for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) 958 DestNMD->addOperand(MapValue(I->getOperand(i), ValueMap, 959 RF_None, &TypeMap)); 960 } 961} 962 963/// categorizeModuleFlagNodes - 964bool ModuleLinker:: 965categorizeModuleFlagNodes(const NamedMDNode *ModFlags, 966 DenseMap<MDString*, MDNode*> &ErrorNode, 967 DenseMap<MDString*, MDNode*> &WarningNode, 968 DenseMap<MDString*, MDNode*> &OverrideNode, 969 DenseMap<MDString*, 970 SmallSetVector<MDNode*, 8> > &RequireNodes, 971 SmallSetVector<MDString*, 16> &SeenIDs) { 972 bool HasErr = false; 973 974 for (unsigned I = 0, E = ModFlags->getNumOperands(); I != E; ++I) { 975 MDNode *Op = ModFlags->getOperand(I); 976 assert(Op->getNumOperands() == 3 && "Invalid module flag metadata!"); 977 assert(isa<ConstantInt>(Op->getOperand(0)) && 978 "Module flag's first operand must be an integer!"); 979 assert(isa<MDString>(Op->getOperand(1)) && 980 "Module flag's second operand must be an MDString!"); 981 982 ConstantInt *Behavior = cast<ConstantInt>(Op->getOperand(0)); 983 MDString *ID = cast<MDString>(Op->getOperand(1)); 984 Value *Val = Op->getOperand(2); 985 switch (Behavior->getZExtValue()) { 986 default: 987 assert(false && "Invalid behavior in module flag metadata!"); 988 break; 989 case Module::Error: { 990 MDNode *&ErrNode = ErrorNode[ID]; 991 if (!ErrNode) ErrNode = Op; 992 if (ErrNode->getOperand(2) != Val) 993 HasErr = emitError("linking module flags '" + ID->getString() + 994 "': IDs have conflicting values"); 995 break; 996 } 997 case Module::Warning: { 998 MDNode *&WarnNode = WarningNode[ID]; 999 if (!WarnNode) WarnNode = Op; 1000 if (WarnNode->getOperand(2) != Val) 1001 errs() << "WARNING: linking module flags '" << ID->getString() 1002 << "': IDs have conflicting values"; 1003 break; 1004 } 1005 case Module::Require: RequireNodes[ID].insert(Op); break; 1006 case Module::Override: { 1007 MDNode *&OvrNode = OverrideNode[ID]; 1008 if (!OvrNode) OvrNode = Op; 1009 if (OvrNode->getOperand(2) != Val) 1010 HasErr = emitError("linking module flags '" + ID->getString() + 1011 "': IDs have conflicting override values"); 1012 break; 1013 } 1014 } 1015 1016 SeenIDs.insert(ID); 1017 } 1018 1019 return HasErr; 1020} 1021 1022/// linkModuleFlagsMetadata - Merge the linker flags in Src into the Dest 1023/// module. 1024bool ModuleLinker::linkModuleFlagsMetadata() { 1025 const NamedMDNode *SrcModFlags = SrcM->getModuleFlagsMetadata(); 1026 if (!SrcModFlags) return false; 1027 1028 NamedMDNode *DstModFlags = DstM->getOrInsertModuleFlagsMetadata(); 1029 1030 // If the destination module doesn't have module flags yet, then just copy 1031 // over the source module's flags. 1032 if (DstModFlags->getNumOperands() == 0) { 1033 for (unsigned I = 0, E = SrcModFlags->getNumOperands(); I != E; ++I) 1034 DstModFlags->addOperand(SrcModFlags->getOperand(I)); 1035 1036 return false; 1037 } 1038 1039 bool HasErr = false; 1040 1041 // Otherwise, we have to merge them based on their behaviors. First, 1042 // categorize all of the nodes in the modules' module flags. If an error or 1043 // warning occurs, then emit the appropriate message(s). 1044 DenseMap<MDString*, MDNode*> ErrorNode; 1045 DenseMap<MDString*, MDNode*> WarningNode; 1046 DenseMap<MDString*, MDNode*> OverrideNode; 1047 DenseMap<MDString*, SmallSetVector<MDNode*, 8> > RequireNodes; 1048 SmallSetVector<MDString*, 16> SeenIDs; 1049 1050 HasErr |= categorizeModuleFlagNodes(SrcModFlags, ErrorNode, WarningNode, 1051 OverrideNode, RequireNodes, SeenIDs); 1052 HasErr |= categorizeModuleFlagNodes(DstModFlags, ErrorNode, WarningNode, 1053 OverrideNode, RequireNodes, SeenIDs); 1054 1055 // Check that there isn't both an error and warning node for a flag. 1056 for (SmallSetVector<MDString*, 16>::iterator 1057 I = SeenIDs.begin(), E = SeenIDs.end(); I != E; ++I) { 1058 MDString *ID = *I; 1059 if (ErrorNode[ID] && WarningNode[ID]) 1060 HasErr = emitError("linking module flags '" + ID->getString() + 1061 "': IDs have conflicting behaviors"); 1062 } 1063 1064 // Early exit if we had an error. 1065 if (HasErr) return true; 1066 1067 // Get the destination's module flags ready for new operands. 1068 DstModFlags->dropAllReferences(); 1069 1070 // Add all of the module flags to the destination module. 1071 DenseMap<MDString*, SmallVector<MDNode*, 4> > AddedNodes; 1072 for (SmallSetVector<MDString*, 16>::iterator 1073 I = SeenIDs.begin(), E = SeenIDs.end(); I != E; ++I) { 1074 MDString *ID = *I; 1075 if (OverrideNode[ID]) { 1076 DstModFlags->addOperand(OverrideNode[ID]); 1077 AddedNodes[ID].push_back(OverrideNode[ID]); 1078 } else if (ErrorNode[ID]) { 1079 DstModFlags->addOperand(ErrorNode[ID]); 1080 AddedNodes[ID].push_back(ErrorNode[ID]); 1081 } else if (WarningNode[ID]) { 1082 DstModFlags->addOperand(WarningNode[ID]); 1083 AddedNodes[ID].push_back(WarningNode[ID]); 1084 } 1085 1086 for (SmallSetVector<MDNode*, 8>::iterator 1087 II = RequireNodes[ID].begin(), IE = RequireNodes[ID].end(); 1088 II != IE; ++II) 1089 DstModFlags->addOperand(*II); 1090 } 1091 1092 // Now check that all of the requirements have been satisfied. 1093 for (SmallSetVector<MDString*, 16>::iterator 1094 I = SeenIDs.begin(), E = SeenIDs.end(); I != E; ++I) { 1095 MDString *ID = *I; 1096 SmallSetVector<MDNode*, 8> &Set = RequireNodes[ID]; 1097 1098 for (SmallSetVector<MDNode*, 8>::iterator 1099 II = Set.begin(), IE = Set.end(); II != IE; ++II) { 1100 MDNode *Node = *II; 1101 assert(isa<MDNode>(Node->getOperand(2)) && 1102 "Module flag's third operand must be an MDNode!"); 1103 MDNode *Val = cast<MDNode>(Node->getOperand(2)); 1104 1105 MDString *ReqID = cast<MDString>(Val->getOperand(0)); 1106 Value *ReqVal = Val->getOperand(1); 1107 1108 bool HasValue = false; 1109 for (SmallVectorImpl<MDNode*>::iterator 1110 RI = AddedNodes[ReqID].begin(), RE = AddedNodes[ReqID].end(); 1111 RI != RE; ++RI) { 1112 MDNode *ReqNode = *RI; 1113 if (ReqNode->getOperand(2) == ReqVal) { 1114 HasValue = true; 1115 break; 1116 } 1117 } 1118 1119 if (!HasValue) 1120 HasErr = emitError("linking module flags '" + ReqID->getString() + 1121 "': does not have the required value"); 1122 } 1123 } 1124 1125 return HasErr; 1126} 1127 1128bool ModuleLinker::run() { 1129 assert(DstM && "Null destination module"); 1130 assert(SrcM && "Null source module"); 1131 1132 // Inherit the target data from the source module if the destination module 1133 // doesn't have one already. 1134 if (DstM->getDataLayout().empty() && !SrcM->getDataLayout().empty()) 1135 DstM->setDataLayout(SrcM->getDataLayout()); 1136 1137 // Copy the target triple from the source to dest if the dest's is empty. 1138 if (DstM->getTargetTriple().empty() && !SrcM->getTargetTriple().empty()) 1139 DstM->setTargetTriple(SrcM->getTargetTriple()); 1140 1141 if (!SrcM->getDataLayout().empty() && !DstM->getDataLayout().empty() && 1142 SrcM->getDataLayout() != DstM->getDataLayout()) 1143 errs() << "WARNING: Linking two modules of different data layouts!\n"; 1144 if (!SrcM->getTargetTriple().empty() && 1145 DstM->getTargetTriple() != SrcM->getTargetTriple()) { 1146 errs() << "WARNING: Linking two modules of different target triples: "; 1147 if (!SrcM->getModuleIdentifier().empty()) 1148 errs() << SrcM->getModuleIdentifier() << ": "; 1149 errs() << "'" << SrcM->getTargetTriple() << "' and '" 1150 << DstM->getTargetTriple() << "'\n"; 1151 } 1152 1153 // Append the module inline asm string. 1154 if (!SrcM->getModuleInlineAsm().empty()) { 1155 if (DstM->getModuleInlineAsm().empty()) 1156 DstM->setModuleInlineAsm(SrcM->getModuleInlineAsm()); 1157 else 1158 DstM->setModuleInlineAsm(DstM->getModuleInlineAsm()+"\n"+ 1159 SrcM->getModuleInlineAsm()); 1160 } 1161 1162 // Update the destination module's dependent libraries list with the libraries 1163 // from the source module. There's no opportunity for duplicates here as the 1164 // Module ensures that duplicate insertions are discarded. 1165 for (Module::lib_iterator SI = SrcM->lib_begin(), SE = SrcM->lib_end(); 1166 SI != SE; ++SI) 1167 DstM->addLibrary(*SI); 1168 1169 // If the source library's module id is in the dependent library list of the 1170 // destination library, remove it since that module is now linked in. 1171 StringRef ModuleId = SrcM->getModuleIdentifier(); 1172 if (!ModuleId.empty()) 1173 DstM->removeLibrary(sys::path::stem(ModuleId)); 1174 1175 // Loop over all of the linked values to compute type mappings. 1176 computeTypeMapping(); 1177 1178 // Insert all of the globals in src into the DstM module... without linking 1179 // initializers (which could refer to functions not yet mapped over). 1180 for (Module::global_iterator I = SrcM->global_begin(), 1181 E = SrcM->global_end(); I != E; ++I) 1182 if (linkGlobalProto(I)) 1183 return true; 1184 1185 // Link the functions together between the two modules, without doing function 1186 // bodies... this just adds external function prototypes to the DstM 1187 // function... We do this so that when we begin processing function bodies, 1188 // all of the global values that may be referenced are available in our 1189 // ValueMap. 1190 for (Module::iterator I = SrcM->begin(), E = SrcM->end(); I != E; ++I) 1191 if (linkFunctionProto(I)) 1192 return true; 1193 1194 // If there were any aliases, link them now. 1195 for (Module::alias_iterator I = SrcM->alias_begin(), 1196 E = SrcM->alias_end(); I != E; ++I) 1197 if (linkAliasProto(I)) 1198 return true; 1199 1200 for (unsigned i = 0, e = AppendingVars.size(); i != e; ++i) 1201 linkAppendingVarInit(AppendingVars[i]); 1202 1203 // Update the initializers in the DstM module now that all globals that may 1204 // be referenced are in DstM. 1205 linkGlobalInits(); 1206 1207 // Link in the function bodies that are defined in the source module into 1208 // DstM. 1209 for (Module::iterator SF = SrcM->begin(), E = SrcM->end(); SF != E; ++SF) { 1210 // Skip if not linking from source. 1211 if (DoNotLinkFromSource.count(SF)) continue; 1212 1213 // Skip if no body (function is external) or materialize. 1214 if (SF->isDeclaration()) { 1215 if (!SF->isMaterializable()) 1216 continue; 1217 if (SF->Materialize(&ErrorMsg)) 1218 return true; 1219 } 1220 1221 linkFunctionBody(cast<Function>(ValueMap[SF]), SF); 1222 } 1223 1224 // Resolve all uses of aliases with aliasees. 1225 linkAliasBodies(); 1226 1227 // Remap all of the named MDNodes in Src into the DstM module. We do this 1228 // after linking GlobalValues so that MDNodes that reference GlobalValues 1229 // are properly remapped. 1230 linkNamedMDNodes(); 1231 1232 // Merge the module flags into the DstM module. 1233 if (linkModuleFlagsMetadata()) 1234 return true; 1235 1236 // Process vector of lazily linked in functions. 1237 bool LinkedInAnyFunctions; 1238 do { 1239 LinkedInAnyFunctions = false; 1240 1241 for(std::vector<Function*>::iterator I = LazilyLinkFunctions.begin(), 1242 E = LazilyLinkFunctions.end(); I != E; ++I) { 1243 if (!*I) 1244 continue; 1245 1246 Function *SF = *I; 1247 Function *DF = cast<Function>(ValueMap[SF]); 1248 1249 if (!DF->use_empty()) { 1250 1251 // Materialize if necessary. 1252 if (SF->isDeclaration()) { 1253 if (!SF->isMaterializable()) 1254 continue; 1255 if (SF->Materialize(&ErrorMsg)) 1256 return true; 1257 } 1258 1259 // Link in function body. 1260 linkFunctionBody(DF, SF); 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 1291//===----------------------------------------------------------------------===// 1292// LinkModules entrypoint. 1293//===----------------------------------------------------------------------===// 1294 1295// LinkModules - This function links two modules together, with the resulting 1296// left module modified to be the composite of the two input modules. If an 1297// error occurs, true is returned and ErrorMsg (if not null) is set to indicate 1298// the problem. Upon failure, the Dest module could be in a modified state, and 1299// shouldn't be relied on to be consistent. 1300bool Linker::LinkModules(Module *Dest, Module *Src, unsigned Mode, 1301 std::string *ErrorMsg) { 1302 ModuleLinker TheLinker(Dest, Src, Mode); 1303 if (TheLinker.run()) { 1304 if (ErrorMsg) *ErrorMsg = TheLinker.ErrorMsg; 1305 return true; 1306 } 1307 1308 return false; 1309} 1310