LinkModules.cpp revision 208b6f69441293d27b61b9d16a69c9bba4d097cb
1//===- lib/Linker/LinkModules.cpp - Module Linker Implementation ----------===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file implements the LLVM module linker. 11// 12//===----------------------------------------------------------------------===// 13 14#include "llvm/Linker.h" 15#include "llvm/Constants.h" 16#include "llvm/DerivedTypes.h" 17#include "llvm/Instructions.h" 18#include "llvm/Module.h" 19#include "llvm/ADT/DenseSet.h" 20#include "llvm/ADT/Optional.h" 21#include "llvm/ADT/SetVector.h" 22#include "llvm/ADT/SmallPtrSet.h" 23#include "llvm/Support/Debug.h" 24#include "llvm/Support/Path.h" 25#include "llvm/Support/raw_ostream.h" 26#include "llvm/Transforms/Utils/Cloning.h" 27#include "llvm/Transforms/Utils/ValueMapper.h" 28#include <cctype> 29using namespace llvm; 30 31//===----------------------------------------------------------------------===// 32// TypeMap implementation. 33//===----------------------------------------------------------------------===// 34 35namespace { 36class TypeMapTy : public ValueMapTypeRemapper { 37 /// MappedTypes - This is a mapping from a source type to a destination type 38 /// to use. 39 DenseMap<Type*, Type*> MappedTypes; 40 41 /// SpeculativeTypes - When checking to see if two subgraphs are isomorphic, 42 /// we speculatively add types to MappedTypes, but keep track of them here in 43 /// case we need to roll back. 44 SmallVector<Type*, 16> SpeculativeTypes; 45 46 /// SrcDefinitionsToResolve - This is a list of non-opaque structs in the 47 /// source module that are mapped to an opaque struct in the destination 48 /// module. 49 SmallVector<StructType*, 16> SrcDefinitionsToResolve; 50 51 /// DstResolvedOpaqueTypes - This is the set of opaque types in the 52 /// destination modules who are getting a body from the source module. 53 SmallPtrSet<StructType*, 16> DstResolvedOpaqueTypes; 54 55public: 56 /// addTypeMapping - Indicate that the specified type in the destination 57 /// module is conceptually equivalent to the specified type in the source 58 /// module. 59 void addTypeMapping(Type *DstTy, Type *SrcTy); 60 61 /// linkDefinedTypeBodies - Produce a body for an opaque type in the dest 62 /// module from a type definition in the source module. 63 void linkDefinedTypeBodies(); 64 65 /// get - Return the mapped type to use for the specified input type from the 66 /// source module. 67 Type *get(Type *SrcTy); 68 69 FunctionType *get(FunctionType *T) {return cast<FunctionType>(get((Type*)T));} 70 71 /// dump - Dump out the type map for debugging purposes. 72 void dump() const { 73 for (DenseMap<Type*, Type*>::const_iterator 74 I = MappedTypes.begin(), E = MappedTypes.end(); I != E; ++I) { 75 dbgs() << "TypeMap: "; 76 I->first->dump(); 77 dbgs() << " => "; 78 I->second->dump(); 79 dbgs() << '\n'; 80 } 81 } 82 83private: 84 Type *getImpl(Type *T); 85 /// remapType - Implement the ValueMapTypeRemapper interface. 86 Type *remapType(Type *SrcTy) { 87 return get(SrcTy); 88 } 89 90 bool areTypesIsomorphic(Type *DstTy, Type *SrcTy); 91}; 92} 93 94void TypeMapTy::addTypeMapping(Type *DstTy, Type *SrcTy) { 95 Type *&Entry = MappedTypes[SrcTy]; 96 if (Entry) return; 97 98 if (DstTy == SrcTy) { 99 Entry = DstTy; 100 return; 101 } 102 103 // Check to see if these types are recursively isomorphic and establish a 104 // mapping between them if so. 105 if (!areTypesIsomorphic(DstTy, SrcTy)) { 106 // Oops, they aren't isomorphic. Just discard this request by rolling out 107 // any speculative mappings we've established. 108 for (unsigned i = 0, e = SpeculativeTypes.size(); i != e; ++i) 109 MappedTypes.erase(SpeculativeTypes[i]); 110 } 111 SpeculativeTypes.clear(); 112} 113 114/// areTypesIsomorphic - Recursively walk this pair of types, returning true 115/// if they are isomorphic, false if they are not. 116bool TypeMapTy::areTypesIsomorphic(Type *DstTy, Type *SrcTy) { 117 // Two types with differing kinds are clearly not isomorphic. 118 if (DstTy->getTypeID() != SrcTy->getTypeID()) return false; 119 120 // If we have an entry in the MappedTypes table, then we have our answer. 121 Type *&Entry = MappedTypes[SrcTy]; 122 if (Entry) 123 return Entry == DstTy; 124 125 // Two identical types are clearly isomorphic. Remember this 126 // non-speculatively. 127 if (DstTy == SrcTy) { 128 Entry = DstTy; 129 return true; 130 } 131 132 // Okay, we have two types with identical kinds that we haven't seen before. 133 134 // If this is an opaque struct type, special case it. 135 if (StructType *SSTy = dyn_cast<StructType>(SrcTy)) { 136 // Mapping an opaque type to any struct, just keep the dest struct. 137 if (SSTy->isOpaque()) { 138 Entry = DstTy; 139 SpeculativeTypes.push_back(SrcTy); 140 return true; 141 } 142 143 // Mapping a non-opaque source type to an opaque dest. If this is the first 144 // type that we're mapping onto this destination type then we succeed. Keep 145 // the dest, but fill it in later. This doesn't need to be speculative. If 146 // this is the second (different) type that we're trying to map onto the 147 // same opaque type then we fail. 148 if (cast<StructType>(DstTy)->isOpaque()) { 149 // We can only map one source type onto the opaque destination type. 150 if (!DstResolvedOpaqueTypes.insert(cast<StructType>(DstTy))) 151 return false; 152 SrcDefinitionsToResolve.push_back(SSTy); 153 Entry = DstTy; 154 return true; 155 } 156 } 157 158 // If the number of subtypes disagree between the two types, then we fail. 159 if (SrcTy->getNumContainedTypes() != DstTy->getNumContainedTypes()) 160 return false; 161 162 // Fail if any of the extra properties (e.g. array size) of the type disagree. 163 if (isa<IntegerType>(DstTy)) 164 return false; // bitwidth disagrees. 165 if (PointerType *PT = dyn_cast<PointerType>(DstTy)) { 166 if (PT->getAddressSpace() != cast<PointerType>(SrcTy)->getAddressSpace()) 167 return false; 168 169 } else if (FunctionType *FT = dyn_cast<FunctionType>(DstTy)) { 170 if (FT->isVarArg() != cast<FunctionType>(SrcTy)->isVarArg()) 171 return false; 172 } else if (StructType *DSTy = dyn_cast<StructType>(DstTy)) { 173 StructType *SSTy = cast<StructType>(SrcTy); 174 if (DSTy->isLiteral() != SSTy->isLiteral() || 175 DSTy->isPacked() != SSTy->isPacked()) 176 return false; 177 } else if (ArrayType *DATy = dyn_cast<ArrayType>(DstTy)) { 178 if (DATy->getNumElements() != cast<ArrayType>(SrcTy)->getNumElements()) 179 return false; 180 } else if (VectorType *DVTy = dyn_cast<VectorType>(DstTy)) { 181 if (DVTy->getNumElements() != cast<ArrayType>(SrcTy)->getNumElements()) 182 return false; 183 } 184 185 // Otherwise, we speculate that these two types will line up and recursively 186 // check the subelements. 187 Entry = DstTy; 188 SpeculativeTypes.push_back(SrcTy); 189 190 for (unsigned i = 0, e = SrcTy->getNumContainedTypes(); i != e; ++i) 191 if (!areTypesIsomorphic(DstTy->getContainedType(i), 192 SrcTy->getContainedType(i))) 193 return false; 194 195 // If everything seems to have lined up, then everything is great. 196 return true; 197} 198 199/// linkDefinedTypeBodies - Produce a body for an opaque type in the dest 200/// module from a type definition in the source module. 201void TypeMapTy::linkDefinedTypeBodies() { 202 SmallVector<Type*, 16> Elements; 203 SmallString<16> TmpName; 204 205 // Note that processing entries in this loop (calling 'get') can add new 206 // entries to the SrcDefinitionsToResolve vector. 207 while (!SrcDefinitionsToResolve.empty()) { 208 StructType *SrcSTy = SrcDefinitionsToResolve.pop_back_val(); 209 StructType *DstSTy = cast<StructType>(MappedTypes[SrcSTy]); 210 211 // TypeMap is a many-to-one mapping, if there were multiple types that 212 // provide a body for DstSTy then previous iterations of this loop may have 213 // already handled it. Just ignore this case. 214 if (!DstSTy->isOpaque()) continue; 215 assert(!SrcSTy->isOpaque() && "Not resolving a definition?"); 216 217 // Map the body of the source type over to a new body for the dest type. 218 Elements.resize(SrcSTy->getNumElements()); 219 for (unsigned i = 0, e = Elements.size(); i != e; ++i) 220 Elements[i] = getImpl(SrcSTy->getElementType(i)); 221 222 DstSTy->setBody(Elements, SrcSTy->isPacked()); 223 224 // If DstSTy has no name or has a longer name than STy, then viciously steal 225 // STy's name. 226 if (!SrcSTy->hasName()) continue; 227 StringRef SrcName = SrcSTy->getName(); 228 229 if (!DstSTy->hasName() || DstSTy->getName().size() > SrcName.size()) { 230 TmpName.insert(TmpName.end(), SrcName.begin(), SrcName.end()); 231 SrcSTy->setName(""); 232 DstSTy->setName(TmpName.str()); 233 TmpName.clear(); 234 } 235 } 236 237 DstResolvedOpaqueTypes.clear(); 238} 239 240/// get - Return the mapped type to use for the specified input type from the 241/// source module. 242Type *TypeMapTy::get(Type *Ty) { 243 Type *Result = getImpl(Ty); 244 245 // If this caused a reference to any struct type, resolve it before returning. 246 if (!SrcDefinitionsToResolve.empty()) 247 linkDefinedTypeBodies(); 248 return Result; 249} 250 251/// getImpl - This is the recursive version of get(). 252Type *TypeMapTy::getImpl(Type *Ty) { 253 // If we already have an entry for this type, return it. 254 Type **Entry = &MappedTypes[Ty]; 255 if (*Entry) return *Entry; 256 257 // If this is not a named struct type, then just map all of the elements and 258 // then rebuild the type from inside out. 259 if (!isa<StructType>(Ty) || cast<StructType>(Ty)->isLiteral()) { 260 // If there are no element types to map, then the type is itself. This is 261 // true for the anonymous {} struct, things like 'float', integers, etc. 262 if (Ty->getNumContainedTypes() == 0) 263 return *Entry = Ty; 264 265 // Remap all of the elements, keeping track of whether any of them change. 266 bool AnyChange = false; 267 SmallVector<Type*, 4> ElementTypes; 268 ElementTypes.resize(Ty->getNumContainedTypes()); 269 for (unsigned i = 0, e = Ty->getNumContainedTypes(); i != e; ++i) { 270 ElementTypes[i] = getImpl(Ty->getContainedType(i)); 271 AnyChange |= ElementTypes[i] != Ty->getContainedType(i); 272 } 273 274 // If we found our type while recursively processing stuff, just use it. 275 Entry = &MappedTypes[Ty]; 276 if (*Entry) return *Entry; 277 278 // If all of the element types mapped directly over, then the type is usable 279 // as-is. 280 if (!AnyChange) 281 return *Entry = Ty; 282 283 // Otherwise, rebuild a modified type. 284 switch (Ty->getTypeID()) { 285 default: llvm_unreachable("unknown derived type to remap"); 286 case Type::ArrayTyID: 287 return *Entry = ArrayType::get(ElementTypes[0], 288 cast<ArrayType>(Ty)->getNumElements()); 289 case Type::VectorTyID: 290 return *Entry = VectorType::get(ElementTypes[0], 291 cast<VectorType>(Ty)->getNumElements()); 292 case Type::PointerTyID: 293 return *Entry = PointerType::get(ElementTypes[0], 294 cast<PointerType>(Ty)->getAddressSpace()); 295 case Type::FunctionTyID: 296 return *Entry = FunctionType::get(ElementTypes[0], 297 makeArrayRef(ElementTypes).slice(1), 298 cast<FunctionType>(Ty)->isVarArg()); 299 case Type::StructTyID: 300 // Note that this is only reached for anonymous structs. 301 return *Entry = StructType::get(Ty->getContext(), ElementTypes, 302 cast<StructType>(Ty)->isPacked()); 303 } 304 } 305 306 // Otherwise, this is an unmapped named struct. If the struct can be directly 307 // mapped over, just use it as-is. This happens in a case when the linked-in 308 // module has something like: 309 // %T = type {%T*, i32} 310 // @GV = global %T* null 311 // where T does not exist at all in the destination module. 312 // 313 // The other case we watch for is when the type is not in the destination 314 // module, but that it has to be rebuilt because it refers to something that 315 // is already mapped. For example, if the destination module has: 316 // %A = type { i32 } 317 // and the source module has something like 318 // %A' = type { i32 } 319 // %B = type { %A'* } 320 // @GV = global %B* null 321 // then we want to create a new type: "%B = type { %A*}" and have it take the 322 // pristine "%B" name from the source module. 323 // 324 // To determine which case this is, we have to recursively walk the type graph 325 // speculating that we'll be able to reuse it unmodified. Only if this is 326 // safe would we map the entire thing over. Because this is an optimization, 327 // and is not required for the prettiness of the linked module, we just skip 328 // it and always rebuild a type here. 329 StructType *STy = cast<StructType>(Ty); 330 331 // If the type is opaque, we can just use it directly. 332 if (STy->isOpaque()) 333 return *Entry = STy; 334 335 // Otherwise we create a new type and resolve its body later. This will be 336 // resolved by the top level of get(). 337 SrcDefinitionsToResolve.push_back(STy); 338 StructType *DTy = StructType::create(STy->getContext()); 339 DstResolvedOpaqueTypes.insert(DTy); 340 return *Entry = DTy; 341} 342 343//===----------------------------------------------------------------------===// 344// ModuleLinker implementation. 345//===----------------------------------------------------------------------===// 346 347namespace { 348 /// ModuleLinker - This is an implementation class for the LinkModules 349 /// function, which is the entrypoint for this file. 350 class ModuleLinker { 351 Module *DstM, *SrcM; 352 353 TypeMapTy TypeMap; 354 355 /// ValueMap - Mapping of values from what they used to be in Src, to what 356 /// they are now in DstM. ValueToValueMapTy is a ValueMap, which involves 357 /// some overhead due to the use of Value handles which the Linker doesn't 358 /// actually need, but this allows us to reuse the ValueMapper code. 359 ValueToValueMapTy ValueMap; 360 361 struct AppendingVarInfo { 362 GlobalVariable *NewGV; // New aggregate global in dest module. 363 Constant *DstInit; // Old initializer from dest module. 364 Constant *SrcInit; // Old initializer from src module. 365 }; 366 367 std::vector<AppendingVarInfo> AppendingVars; 368 369 unsigned Mode; // Mode to treat source module. 370 371 // Set of items not to link in from source. 372 SmallPtrSet<const Value*, 16> DoNotLinkFromSource; 373 374 // Vector of functions to lazily link in. 375 std::vector<Function*> LazilyLinkFunctions; 376 377 public: 378 std::string ErrorMsg; 379 380 ModuleLinker(Module *dstM, Module *srcM, unsigned mode) 381 : DstM(dstM), SrcM(srcM), Mode(mode) { } 382 383 bool run(); 384 385 private: 386 /// emitError - Helper method for setting a message and returning an error 387 /// code. 388 bool emitError(const Twine &Message) { 389 ErrorMsg = Message.str(); 390 return true; 391 } 392 393 /// getLinkageResult - This analyzes the two global values and determines 394 /// what the result will look like in the destination module. 395 bool getLinkageResult(GlobalValue *Dest, const GlobalValue *Src, 396 GlobalValue::LinkageTypes <, 397 GlobalValue::VisibilityTypes &Vis, 398 bool &LinkFromSrc); 399 400 /// getLinkedToGlobal - Given a global in the source module, return the 401 /// global in the destination module that is being linked to, if any. 402 GlobalValue *getLinkedToGlobal(GlobalValue *SrcGV) { 403 // If the source has no name it can't link. If it has local linkage, 404 // there is no name match-up going on. 405 if (!SrcGV->hasName() || SrcGV->hasLocalLinkage()) 406 return 0; 407 408 // Otherwise see if we have a match in the destination module's symtab. 409 GlobalValue *DGV = DstM->getNamedValue(SrcGV->getName()); 410 if (DGV == 0) return 0; 411 412 // If we found a global with the same name in the dest module, but it has 413 // internal linkage, we are really not doing any linkage here. 414 if (DGV->hasLocalLinkage()) 415 return 0; 416 417 // Otherwise, we do in fact link to the destination global. 418 return DGV; 419 } 420 421 void computeTypeMapping(); 422 bool categorizeModuleFlagNodes(const NamedMDNode *ModFlags, 423 DenseMap<MDString*, MDNode*> &ErrorNode, 424 DenseMap<MDString*, MDNode*> &WarningNode, 425 DenseMap<MDString*, MDNode*> &OverrideNode, 426 DenseMap<MDString*, 427 SmallSetVector<MDNode*, 8> > &RequireNodes, 428 SmallSetVector<MDString*, 16> &SeenIDs); 429 430 bool linkAppendingVarProto(GlobalVariable *DstGV, GlobalVariable *SrcGV); 431 bool linkGlobalProto(GlobalVariable *SrcGV); 432 bool linkFunctionProto(Function *SrcF); 433 bool linkAliasProto(GlobalAlias *SrcA); 434 bool linkModuleFlagsMetadata(); 435 436 void linkAppendingVarInit(const AppendingVarInfo &AVI); 437 void linkGlobalInits(); 438 void linkFunctionBody(Function *Dst, Function *Src); 439 void linkAliasBodies(); 440 void linkNamedMDNodes(); 441 }; 442} 443 444/// forceRenaming - The LLVM SymbolTable class autorenames globals that conflict 445/// in the symbol table. This is good for all clients except for us. Go 446/// through the trouble to force this back. 447static void forceRenaming(GlobalValue *GV, StringRef Name) { 448 // If the global doesn't force its name or if it already has the right name, 449 // there is nothing for us to do. 450 if (GV->hasLocalLinkage() || GV->getName() == Name) 451 return; 452 453 Module *M = GV->getParent(); 454 455 // If there is a conflict, rename the conflict. 456 if (GlobalValue *ConflictGV = M->getNamedValue(Name)) { 457 GV->takeName(ConflictGV); 458 ConflictGV->setName(Name); // This will cause ConflictGV to get renamed 459 assert(ConflictGV->getName() != Name && "forceRenaming didn't work"); 460 } else { 461 GV->setName(Name); // Force the name back 462 } 463} 464 465/// copyGVAttributes - copy additional attributes (those not needed to construct 466/// a GlobalValue) from the SrcGV to the DestGV. 467static void copyGVAttributes(GlobalValue *DestGV, const GlobalValue *SrcGV) { 468 // Use the maximum alignment, rather than just copying the alignment of SrcGV. 469 unsigned Alignment = std::max(DestGV->getAlignment(), SrcGV->getAlignment()); 470 DestGV->copyAttributesFrom(SrcGV); 471 DestGV->setAlignment(Alignment); 472 473 forceRenaming(DestGV, SrcGV->getName()); 474} 475 476static bool isLessConstraining(GlobalValue::VisibilityTypes a, 477 GlobalValue::VisibilityTypes b) { 478 if (a == GlobalValue::HiddenVisibility) 479 return false; 480 if (b == GlobalValue::HiddenVisibility) 481 return true; 482 if (a == GlobalValue::ProtectedVisibility) 483 return false; 484 if (b == GlobalValue::ProtectedVisibility) 485 return true; 486 return false; 487} 488 489/// getLinkageResult - This analyzes the two global values and determines what 490/// the result will look like in the destination module. In particular, it 491/// computes the resultant linkage type and visibility, computes whether the 492/// global in the source should be copied over to the destination (replacing 493/// the existing one), and computes whether this linkage is an error or not. 494bool ModuleLinker::getLinkageResult(GlobalValue *Dest, const GlobalValue *Src, 495 GlobalValue::LinkageTypes <, 496 GlobalValue::VisibilityTypes &Vis, 497 bool &LinkFromSrc) { 498 assert(Dest && "Must have two globals being queried"); 499 assert(!Src->hasLocalLinkage() && 500 "If Src has internal linkage, Dest shouldn't be set!"); 501 502 bool SrcIsDeclaration = Src->isDeclaration() && !Src->isMaterializable(); 503 bool DestIsDeclaration = Dest->isDeclaration(); 504 505 if (SrcIsDeclaration) { 506 // If Src is external or if both Src & Dest are external.. Just link the 507 // external globals, we aren't adding anything. 508 if (Src->hasDLLImportLinkage()) { 509 // If one of GVs has DLLImport linkage, result should be dllimport'ed. 510 if (DestIsDeclaration) { 511 LinkFromSrc = true; 512 LT = Src->getLinkage(); 513 } 514 } else if (Dest->hasExternalWeakLinkage()) { 515 // If the Dest is weak, use the source linkage. 516 LinkFromSrc = true; 517 LT = Src->getLinkage(); 518 } else { 519 LinkFromSrc = false; 520 LT = Dest->getLinkage(); 521 } 522 } else if (DestIsDeclaration && !Dest->hasDLLImportLinkage()) { 523 // If Dest is external but Src is not: 524 LinkFromSrc = true; 525 LT = Src->getLinkage(); 526 } else if (Src->isWeakForLinker()) { 527 // At this point we know that Dest has LinkOnce, External*, Weak, Common, 528 // or DLL* linkage. 529 if (Dest->hasExternalWeakLinkage() || 530 Dest->hasAvailableExternallyLinkage() || 531 (Dest->hasLinkOnceLinkage() && 532 (Src->hasWeakLinkage() || Src->hasCommonLinkage()))) { 533 LinkFromSrc = true; 534 LT = Src->getLinkage(); 535 } else { 536 LinkFromSrc = false; 537 LT = Dest->getLinkage(); 538 } 539 } else if (Dest->isWeakForLinker()) { 540 // At this point we know that Src has External* or DLL* linkage. 541 if (Src->hasExternalWeakLinkage()) { 542 LinkFromSrc = false; 543 LT = Dest->getLinkage(); 544 } else { 545 LinkFromSrc = true; 546 LT = GlobalValue::ExternalLinkage; 547 } 548 } else { 549 assert((Dest->hasExternalLinkage() || Dest->hasDLLImportLinkage() || 550 Dest->hasDLLExportLinkage() || Dest->hasExternalWeakLinkage()) && 551 (Src->hasExternalLinkage() || Src->hasDLLImportLinkage() || 552 Src->hasDLLExportLinkage() || Src->hasExternalWeakLinkage()) && 553 "Unexpected linkage type!"); 554 return emitError("Linking globals named '" + Src->getName() + 555 "': symbol multiply defined!"); 556 } 557 558 // Compute the visibility. We follow the rules in the System V Application 559 // Binary Interface. 560 Vis = isLessConstraining(Src->getVisibility(), Dest->getVisibility()) ? 561 Dest->getVisibility() : Src->getVisibility(); 562 return false; 563} 564 565/// computeTypeMapping - Loop over all of the linked values to compute type 566/// mappings. For example, if we link "extern Foo *x" and "Foo *x = NULL", then 567/// we have two struct types 'Foo' but one got renamed when the module was 568/// loaded into the same LLVMContext. 569void ModuleLinker::computeTypeMapping() { 570 // Incorporate globals. 571 for (Module::global_iterator I = SrcM->global_begin(), 572 E = SrcM->global_end(); I != E; ++I) { 573 GlobalValue *DGV = getLinkedToGlobal(I); 574 if (DGV == 0) continue; 575 576 if (!DGV->hasAppendingLinkage() || !I->hasAppendingLinkage()) { 577 TypeMap.addTypeMapping(DGV->getType(), I->getType()); 578 continue; 579 } 580 581 // Unify the element type of appending arrays. 582 ArrayType *DAT = cast<ArrayType>(DGV->getType()->getElementType()); 583 ArrayType *SAT = cast<ArrayType>(I->getType()->getElementType()); 584 TypeMap.addTypeMapping(DAT->getElementType(), SAT->getElementType()); 585 } 586 587 // Incorporate functions. 588 for (Module::iterator I = SrcM->begin(), E = SrcM->end(); I != E; ++I) { 589 if (GlobalValue *DGV = getLinkedToGlobal(I)) 590 TypeMap.addTypeMapping(DGV->getType(), I->getType()); 591 } 592 593 // Incorporate types by name, scanning all the types in the source module. 594 // At this point, the destination module may have a type "%foo = { i32 }" for 595 // example. When the source module got loaded into the same LLVMContext, if 596 // it had the same type, it would have been renamed to "%foo.42 = { i32 }". 597 std::vector<StructType*> SrcStructTypes; 598 SrcM->findUsedStructTypes(SrcStructTypes); 599 600 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() == '.' || !isdigit(ST->getName()[DotPos+1])) 611 continue; 612 613 // Check to see if the destination module has a struct with the prefix name. 614 if (StructType *DST = DstM->getTypeByName(ST->getName().substr(0, DotPos))) 615 // Don't use it if this actually came from the source module. They're in 616 // the same LLVMContext after all. 617 if (!SrcStructTypesSet.count(DST)) 618 TypeMap.addTypeMapping(DST, ST); 619 } 620 621 // Don't bother incorporating aliases, they aren't generally typed well. 622 623 // Now that we have discovered all of the type equivalences, get a body for 624 // any 'opaque' types in the dest module that are now resolved. 625 TypeMap.linkDefinedTypeBodies(); 626} 627 628/// linkAppendingVarProto - If there were any appending global variables, link 629/// them together now. Return true on error. 630bool ModuleLinker::linkAppendingVarProto(GlobalVariable *DstGV, 631 GlobalVariable *SrcGV) { 632 633 if (!SrcGV->hasAppendingLinkage() || !DstGV->hasAppendingLinkage()) 634 return emitError("Linking globals named '" + SrcGV->getName() + 635 "': can only link appending global with another appending global!"); 636 637 ArrayType *DstTy = cast<ArrayType>(DstGV->getType()->getElementType()); 638 ArrayType *SrcTy = 639 cast<ArrayType>(TypeMap.get(SrcGV->getType()->getElementType())); 640 Type *EltTy = DstTy->getElementType(); 641 642 // Check to see that they two arrays agree on type. 643 if (EltTy != SrcTy->getElementType()) 644 return emitError("Appending variables with different element types!"); 645 if (DstGV->isConstant() != SrcGV->isConstant()) 646 return emitError("Appending variables linked with different const'ness!"); 647 648 if (DstGV->getAlignment() != SrcGV->getAlignment()) 649 return emitError( 650 "Appending variables with different alignment need to be linked!"); 651 652 if (DstGV->getVisibility() != SrcGV->getVisibility()) 653 return emitError( 654 "Appending variables with different visibility need to be linked!"); 655 656 if (DstGV->getSection() != SrcGV->getSection()) 657 return emitError( 658 "Appending variables with different section name need to be linked!"); 659 660 uint64_t NewSize = DstTy->getNumElements() + SrcTy->getNumElements(); 661 ArrayType *NewType = ArrayType::get(EltTy, NewSize); 662 663 // Create the new global variable. 664 GlobalVariable *NG = 665 new GlobalVariable(*DstGV->getParent(), NewType, SrcGV->isConstant(), 666 DstGV->getLinkage(), /*init*/0, /*name*/"", DstGV, 667 DstGV->isThreadLocal(), 668 DstGV->getType()->getAddressSpace()); 669 670 // Propagate alignment, visibility and section info. 671 copyGVAttributes(NG, DstGV); 672 673 AppendingVarInfo AVI; 674 AVI.NewGV = NG; 675 AVI.DstInit = DstGV->getInitializer(); 676 AVI.SrcInit = SrcGV->getInitializer(); 677 AppendingVars.push_back(AVI); 678 679 // Replace any uses of the two global variables with uses of the new 680 // global. 681 ValueMap[SrcGV] = ConstantExpr::getBitCast(NG, TypeMap.get(SrcGV->getType())); 682 683 DstGV->replaceAllUsesWith(ConstantExpr::getBitCast(NG, DstGV->getType())); 684 DstGV->eraseFromParent(); 685 686 // Track the source variable so we don't try to link it. 687 DoNotLinkFromSource.insert(SrcGV); 688 689 return false; 690} 691 692/// linkGlobalProto - Loop through the global variables in the src module and 693/// merge them into the dest module. 694bool ModuleLinker::linkGlobalProto(GlobalVariable *SGV) { 695 GlobalValue *DGV = getLinkedToGlobal(SGV); 696 llvm::Optional<GlobalValue::VisibilityTypes> NewVisibility; 697 698 if (DGV) { 699 // Concatenation of appending linkage variables is magic and handled later. 700 if (DGV->hasAppendingLinkage() || SGV->hasAppendingLinkage()) 701 return linkAppendingVarProto(cast<GlobalVariable>(DGV), SGV); 702 703 // Determine whether linkage of these two globals follows the source 704 // module's definition or the destination module's definition. 705 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; 706 GlobalValue::VisibilityTypes NV; 707 bool LinkFromSrc = false; 708 if (getLinkageResult(DGV, SGV, NewLinkage, NV, LinkFromSrc)) 709 return true; 710 NewVisibility = NV; 711 712 // If we're not linking from the source, then keep the definition that we 713 // have. 714 if (!LinkFromSrc) { 715 // Special case for const propagation. 716 if (GlobalVariable *DGVar = dyn_cast<GlobalVariable>(DGV)) 717 if (DGVar->isDeclaration() && SGV->isConstant() && !DGVar->isConstant()) 718 DGVar->setConstant(true); 719 720 // Set calculated linkage and visibility. 721 DGV->setLinkage(NewLinkage); 722 DGV->setVisibility(*NewVisibility); 723 724 // Make sure to remember this mapping. 725 ValueMap[SGV] = ConstantExpr::getBitCast(DGV,TypeMap.get(SGV->getType())); 726 727 // Track the source global so that we don't attempt to copy it over when 728 // processing global initializers. 729 DoNotLinkFromSource.insert(SGV); 730 731 return false; 732 } 733 } 734 735 // No linking to be performed or linking from the source: simply create an 736 // identical version of the symbol over in the dest module... the 737 // initializer will be filled in later by LinkGlobalInits. 738 GlobalVariable *NewDGV = 739 new GlobalVariable(*DstM, TypeMap.get(SGV->getType()->getElementType()), 740 SGV->isConstant(), SGV->getLinkage(), /*init*/0, 741 SGV->getName(), /*insertbefore*/0, 742 SGV->isThreadLocal(), 743 SGV->getType()->getAddressSpace()); 744 // Propagate alignment, visibility and section info. 745 copyGVAttributes(NewDGV, SGV); 746 if (NewVisibility) 747 NewDGV->setVisibility(*NewVisibility); 748 749 if (DGV) { 750 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDGV, DGV->getType())); 751 DGV->eraseFromParent(); 752 } 753 754 // Make sure to remember this mapping. 755 ValueMap[SGV] = NewDGV; 756 return false; 757} 758 759/// linkFunctionProto - Link the function in the source module into the 760/// destination module if needed, setting up mapping information. 761bool ModuleLinker::linkFunctionProto(Function *SF) { 762 GlobalValue *DGV = getLinkedToGlobal(SF); 763 llvm::Optional<GlobalValue::VisibilityTypes> NewVisibility; 764 765 if (DGV) { 766 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; 767 bool LinkFromSrc = false; 768 GlobalValue::VisibilityTypes NV; 769 if (getLinkageResult(DGV, SF, NewLinkage, NV, LinkFromSrc)) 770 return true; 771 NewVisibility = NV; 772 773 if (!LinkFromSrc) { 774 // Set calculated linkage 775 DGV->setLinkage(NewLinkage); 776 DGV->setVisibility(*NewVisibility); 777 778 // Make sure to remember this mapping. 779 ValueMap[SF] = ConstantExpr::getBitCast(DGV, TypeMap.get(SF->getType())); 780 781 // Track the function from the source module so we don't attempt to remap 782 // it. 783 DoNotLinkFromSource.insert(SF); 784 785 return false; 786 } 787 } 788 789 // If there is no linkage to be performed or we are linking from the source, 790 // bring SF over. 791 Function *NewDF = Function::Create(TypeMap.get(SF->getFunctionType()), 792 SF->getLinkage(), SF->getName(), DstM); 793 copyGVAttributes(NewDF, SF); 794 if (NewVisibility) 795 NewDF->setVisibility(*NewVisibility); 796 797 if (DGV) { 798 // Any uses of DF need to change to NewDF, with cast. 799 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDF, DGV->getType())); 800 DGV->eraseFromParent(); 801 } else { 802 // Internal, LO_ODR, or LO linkage - stick in set to ignore and lazily link. 803 if (SF->hasLocalLinkage() || SF->hasLinkOnceLinkage() || 804 SF->hasAvailableExternallyLinkage()) { 805 DoNotLinkFromSource.insert(SF); 806 LazilyLinkFunctions.push_back(SF); 807 } 808 } 809 810 ValueMap[SF] = NewDF; 811 return false; 812} 813 814/// LinkAliasProto - Set up prototypes for any aliases that come over from the 815/// source module. 816bool ModuleLinker::linkAliasProto(GlobalAlias *SGA) { 817 GlobalValue *DGV = getLinkedToGlobal(SGA); 818 llvm::Optional<GlobalValue::VisibilityTypes> NewVisibility; 819 820 if (DGV) { 821 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; 822 GlobalValue::VisibilityTypes NV; 823 bool LinkFromSrc = false; 824 if (getLinkageResult(DGV, SGA, NewLinkage, NV, LinkFromSrc)) 825 return true; 826 NewVisibility = NV; 827 828 if (!LinkFromSrc) { 829 // Set calculated linkage. 830 DGV->setLinkage(NewLinkage); 831 DGV->setVisibility(*NewVisibility); 832 833 // Make sure to remember this mapping. 834 ValueMap[SGA] = ConstantExpr::getBitCast(DGV,TypeMap.get(SGA->getType())); 835 836 // Track the alias from the source module so we don't attempt to remap it. 837 DoNotLinkFromSource.insert(SGA); 838 839 return false; 840 } 841 } 842 843 // If there is no linkage to be performed or we're linking from the source, 844 // bring over SGA. 845 GlobalAlias *NewDA = new GlobalAlias(TypeMap.get(SGA->getType()), 846 SGA->getLinkage(), SGA->getName(), 847 /*aliasee*/0, DstM); 848 copyGVAttributes(NewDA, SGA); 849 if (NewVisibility) 850 NewDA->setVisibility(*NewVisibility); 851 852 if (DGV) { 853 // Any uses of DGV need to change to NewDA, with cast. 854 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDA, DGV->getType())); 855 DGV->eraseFromParent(); 856 } 857 858 ValueMap[SGA] = NewDA; 859 return false; 860} 861 862static void getArrayElements(Constant *C, SmallVectorImpl<Constant*> &Dest) { 863 unsigned NumElements = cast<ArrayType>(C->getType())->getNumElements(); 864 865 for (unsigned i = 0; i != NumElements; ++i) 866 Dest.push_back(C->getAggregateElement(i)); 867} 868 869void ModuleLinker::linkAppendingVarInit(const AppendingVarInfo &AVI) { 870 // Merge the initializer. 871 SmallVector<Constant*, 16> Elements; 872 getArrayElements(AVI.DstInit, Elements); 873 874 Constant *SrcInit = MapValue(AVI.SrcInit, ValueMap, RF_None, &TypeMap); 875 getArrayElements(SrcInit, Elements); 876 877 ArrayType *NewType = cast<ArrayType>(AVI.NewGV->getType()->getElementType()); 878 AVI.NewGV->setInitializer(ConstantArray::get(NewType, Elements)); 879} 880 881/// linkGlobalInits - Update the initializers in the Dest module now that all 882/// globals that may be referenced are in Dest. 883void ModuleLinker::linkGlobalInits() { 884 // Loop over all of the globals in the src module, mapping them over as we go 885 for (Module::const_global_iterator I = SrcM->global_begin(), 886 E = SrcM->global_end(); I != E; ++I) { 887 888 // Only process initialized GV's or ones not already in dest. 889 if (!I->hasInitializer() || DoNotLinkFromSource.count(I)) continue; 890 891 // Grab destination global variable. 892 GlobalVariable *DGV = cast<GlobalVariable>(ValueMap[I]); 893 // Figure out what the initializer looks like in the dest module. 894 DGV->setInitializer(MapValue(I->getInitializer(), ValueMap, 895 RF_None, &TypeMap)); 896 } 897} 898 899/// linkFunctionBody - Copy the source function over into the dest function and 900/// fix up references to values. At this point we know that Dest is an external 901/// function, and that Src is not. 902void ModuleLinker::linkFunctionBody(Function *Dst, Function *Src) { 903 assert(Src && Dst && Dst->isDeclaration() && !Src->isDeclaration()); 904 905 // Go through and convert function arguments over, remembering the mapping. 906 Function::arg_iterator DI = Dst->arg_begin(); 907 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end(); 908 I != E; ++I, ++DI) { 909 DI->setName(I->getName()); // Copy the name over. 910 911 // Add a mapping to our mapping. 912 ValueMap[I] = DI; 913 } 914 915 if (Mode == Linker::DestroySource) { 916 // Splice the body of the source function into the dest function. 917 Dst->getBasicBlockList().splice(Dst->end(), Src->getBasicBlockList()); 918 919 // At this point, all of the instructions and values of the function are now 920 // copied over. The only problem is that they are still referencing values in 921 // the Source function as operands. Loop through all of the operands of the 922 // functions and patch them up to point to the local versions. 923 for (Function::iterator BB = Dst->begin(), BE = Dst->end(); BB != BE; ++BB) 924 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) 925 RemapInstruction(I, ValueMap, RF_IgnoreMissingEntries, &TypeMap); 926 927 } else { 928 // Clone the body of the function into the dest function. 929 SmallVector<ReturnInst*, 8> Returns; // Ignore returns. 930 CloneFunctionInto(Dst, Src, ValueMap, false, Returns, "", NULL, &TypeMap); 931 } 932 933 // There is no need to map the arguments anymore. 934 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end(); 935 I != E; ++I) 936 ValueMap.erase(I); 937 938} 939 940/// linkAliasBodies - Insert all of the aliases in Src into the Dest module. 941void ModuleLinker::linkAliasBodies() { 942 for (Module::alias_iterator I = SrcM->alias_begin(), E = SrcM->alias_end(); 943 I != E; ++I) { 944 if (DoNotLinkFromSource.count(I)) 945 continue; 946 if (Constant *Aliasee = I->getAliasee()) { 947 GlobalAlias *DA = cast<GlobalAlias>(ValueMap[I]); 948 DA->setAliasee(MapValue(Aliasee, ValueMap, RF_None, &TypeMap)); 949 } 950 } 951} 952 953/// linkNamedMDNodes - Insert all of the named MDNodes in Src into the Dest 954/// module. 955void ModuleLinker::linkNamedMDNodes() { 956 const NamedMDNode *SrcModFlags = SrcM->getModuleFlagsMetadata(); 957 for (Module::const_named_metadata_iterator I = SrcM->named_metadata_begin(), 958 E = SrcM->named_metadata_end(); I != E; ++I) { 959 // Don't link module flags here. Do them separately. 960 if (&*I == SrcModFlags) continue; 961 NamedMDNode *DestNMD = DstM->getOrInsertNamedMetadata(I->getName()); 962 // Add Src elements into Dest node. 963 for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) 964 DestNMD->addOperand(MapValue(I->getOperand(i), ValueMap, 965 RF_None, &TypeMap)); 966 } 967} 968 969/// categorizeModuleFlagNodes - Categorize the module flags according to their 970/// type: Error, Warning, Override, and Require. 971bool ModuleLinker:: 972categorizeModuleFlagNodes(const NamedMDNode *ModFlags, 973 DenseMap<MDString*, MDNode*> &ErrorNode, 974 DenseMap<MDString*, MDNode*> &WarningNode, 975 DenseMap<MDString*, MDNode*> &OverrideNode, 976 DenseMap<MDString*, 977 SmallSetVector<MDNode*, 8> > &RequireNodes, 978 SmallSetVector<MDString*, 16> &SeenIDs) { 979 bool HasErr = false; 980 981 for (unsigned I = 0, E = ModFlags->getNumOperands(); I != E; ++I) { 982 MDNode *Op = ModFlags->getOperand(I); 983 assert(Op->getNumOperands() == 3 && "Invalid module flag metadata!"); 984 assert(isa<ConstantInt>(Op->getOperand(0)) && 985 "Module flag's first operand must be an integer!"); 986 assert(isa<MDString>(Op->getOperand(1)) && 987 "Module flag's second operand must be an MDString!"); 988 989 ConstantInt *Behavior = cast<ConstantInt>(Op->getOperand(0)); 990 MDString *ID = cast<MDString>(Op->getOperand(1)); 991 Value *Val = Op->getOperand(2); 992 switch (Behavior->getZExtValue()) { 993 default: 994 assert(false && "Invalid behavior in module flag metadata!"); 995 break; 996 case Module::Error: { 997 MDNode *&ErrNode = ErrorNode[ID]; 998 if (!ErrNode) ErrNode = Op; 999 if (ErrNode->getOperand(2) != Val) 1000 HasErr = emitError("linking module flags '" + ID->getString() + 1001 "': IDs have conflicting values"); 1002 break; 1003 } 1004 case Module::Warning: { 1005 MDNode *&WarnNode = WarningNode[ID]; 1006 if (!WarnNode) WarnNode = Op; 1007 if (WarnNode->getOperand(2) != Val) 1008 errs() << "WARNING: linking module flags '" << ID->getString() 1009 << "': IDs have conflicting values"; 1010 break; 1011 } 1012 case Module::Require: RequireNodes[ID].insert(Op); break; 1013 case Module::Override: { 1014 MDNode *&OvrNode = OverrideNode[ID]; 1015 if (!OvrNode) OvrNode = Op; 1016 if (OvrNode->getOperand(2) != Val) 1017 HasErr = emitError("linking module flags '" + ID->getString() + 1018 "': IDs have conflicting override values"); 1019 break; 1020 } 1021 } 1022 1023 SeenIDs.insert(ID); 1024 } 1025 1026 return HasErr; 1027} 1028 1029/// linkModuleFlagsMetadata - Merge the linker flags in Src into the Dest 1030/// module. 1031bool ModuleLinker::linkModuleFlagsMetadata() { 1032 const NamedMDNode *SrcModFlags = SrcM->getModuleFlagsMetadata(); 1033 if (!SrcModFlags) return false; 1034 1035 NamedMDNode *DstModFlags = DstM->getOrInsertModuleFlagsMetadata(); 1036 1037 // If the destination module doesn't have module flags yet, then just copy 1038 // over the source module's flags. 1039 if (DstModFlags->getNumOperands() == 0) { 1040 for (unsigned I = 0, E = SrcModFlags->getNumOperands(); I != E; ++I) 1041 DstModFlags->addOperand(SrcModFlags->getOperand(I)); 1042 1043 return false; 1044 } 1045 1046 bool HasErr = false; 1047 1048 // Otherwise, we have to merge them based on their behaviors. First, 1049 // categorize all of the nodes in the modules' module flags. If an error or 1050 // warning occurs, then emit the appropriate message(s). 1051 DenseMap<MDString*, MDNode*> ErrorNode; 1052 DenseMap<MDString*, MDNode*> WarningNode; 1053 DenseMap<MDString*, MDNode*> OverrideNode; 1054 DenseMap<MDString*, SmallSetVector<MDNode*, 8> > RequireNodes; 1055 SmallSetVector<MDString*, 16> SeenIDs; 1056 1057 HasErr |= categorizeModuleFlagNodes(SrcModFlags, ErrorNode, WarningNode, 1058 OverrideNode, RequireNodes, SeenIDs); 1059 HasErr |= categorizeModuleFlagNodes(DstModFlags, ErrorNode, WarningNode, 1060 OverrideNode, RequireNodes, SeenIDs); 1061 1062 // Check that there isn't both an error and warning node for a flag. 1063 for (SmallSetVector<MDString*, 16>::iterator 1064 I = SeenIDs.begin(), E = SeenIDs.end(); I != E; ++I) { 1065 MDString *ID = *I; 1066 if (ErrorNode[ID] && WarningNode[ID]) 1067 HasErr = emitError("linking module flags '" + ID->getString() + 1068 "': IDs have conflicting behaviors"); 1069 } 1070 1071 // Early exit if we had an error. 1072 if (HasErr) return true; 1073 1074 // Get the destination's module flags ready for new operands. 1075 DstModFlags->dropAllReferences(); 1076 1077 // Add all of the module flags to the destination module. 1078 DenseMap<MDString*, SmallVector<MDNode*, 4> > AddedNodes; 1079 for (SmallSetVector<MDString*, 16>::iterator 1080 I = SeenIDs.begin(), E = SeenIDs.end(); I != E; ++I) { 1081 MDString *ID = *I; 1082 if (OverrideNode[ID]) { 1083 DstModFlags->addOperand(OverrideNode[ID]); 1084 AddedNodes[ID].push_back(OverrideNode[ID]); 1085 } else if (ErrorNode[ID]) { 1086 DstModFlags->addOperand(ErrorNode[ID]); 1087 AddedNodes[ID].push_back(ErrorNode[ID]); 1088 } else if (WarningNode[ID]) { 1089 DstModFlags->addOperand(WarningNode[ID]); 1090 AddedNodes[ID].push_back(WarningNode[ID]); 1091 } 1092 1093 for (SmallSetVector<MDNode*, 8>::iterator 1094 II = RequireNodes[ID].begin(), IE = RequireNodes[ID].end(); 1095 II != IE; ++II) 1096 DstModFlags->addOperand(*II); 1097 } 1098 1099 // Now check that all of the requirements have been satisfied. 1100 for (SmallSetVector<MDString*, 16>::iterator 1101 I = SeenIDs.begin(), E = SeenIDs.end(); I != E; ++I) { 1102 MDString *ID = *I; 1103 SmallSetVector<MDNode*, 8> &Set = RequireNodes[ID]; 1104 1105 for (SmallSetVector<MDNode*, 8>::iterator 1106 II = Set.begin(), IE = Set.end(); II != IE; ++II) { 1107 MDNode *Node = *II; 1108 assert(isa<MDNode>(Node->getOperand(2)) && 1109 "Module flag's third operand must be an MDNode!"); 1110 MDNode *Val = cast<MDNode>(Node->getOperand(2)); 1111 1112 MDString *ReqID = cast<MDString>(Val->getOperand(0)); 1113 Value *ReqVal = Val->getOperand(1); 1114 1115 bool HasValue = false; 1116 for (SmallVectorImpl<MDNode*>::iterator 1117 RI = AddedNodes[ReqID].begin(), RE = AddedNodes[ReqID].end(); 1118 RI != RE; ++RI) { 1119 MDNode *ReqNode = *RI; 1120 if (ReqNode->getOperand(2) == ReqVal) { 1121 HasValue = true; 1122 break; 1123 } 1124 } 1125 1126 if (!HasValue) 1127 HasErr = emitError("linking module flags '" + ReqID->getString() + 1128 "': does not have the required value"); 1129 } 1130 } 1131 1132 return HasErr; 1133} 1134 1135bool ModuleLinker::run() { 1136 assert(DstM && "Null destination module"); 1137 assert(SrcM && "Null source module"); 1138 1139 // Inherit the target data from the source module if the destination module 1140 // doesn't have one already. 1141 if (DstM->getDataLayout().empty() && !SrcM->getDataLayout().empty()) 1142 DstM->setDataLayout(SrcM->getDataLayout()); 1143 1144 // Copy the target triple from the source to dest if the dest's is empty. 1145 if (DstM->getTargetTriple().empty() && !SrcM->getTargetTriple().empty()) 1146 DstM->setTargetTriple(SrcM->getTargetTriple()); 1147 1148 if (!SrcM->getDataLayout().empty() && !DstM->getDataLayout().empty() && 1149 SrcM->getDataLayout() != DstM->getDataLayout()) 1150 errs() << "WARNING: Linking two modules of different data layouts!\n"; 1151 if (!SrcM->getTargetTriple().empty() && 1152 DstM->getTargetTriple() != SrcM->getTargetTriple()) { 1153 errs() << "WARNING: Linking two modules of different target triples: "; 1154 if (!SrcM->getModuleIdentifier().empty()) 1155 errs() << SrcM->getModuleIdentifier() << ": "; 1156 errs() << "'" << SrcM->getTargetTriple() << "' and '" 1157 << DstM->getTargetTriple() << "'\n"; 1158 } 1159 1160 // Append the module inline asm string. 1161 if (!SrcM->getModuleInlineAsm().empty()) { 1162 if (DstM->getModuleInlineAsm().empty()) 1163 DstM->setModuleInlineAsm(SrcM->getModuleInlineAsm()); 1164 else 1165 DstM->setModuleInlineAsm(DstM->getModuleInlineAsm()+"\n"+ 1166 SrcM->getModuleInlineAsm()); 1167 } 1168 1169 // Update the destination module's dependent libraries list with the libraries 1170 // from the source module. There's no opportunity for duplicates here as the 1171 // Module ensures that duplicate insertions are discarded. 1172 for (Module::lib_iterator SI = SrcM->lib_begin(), SE = SrcM->lib_end(); 1173 SI != SE; ++SI) 1174 DstM->addLibrary(*SI); 1175 1176 // If the source library's module id is in the dependent library list of the 1177 // destination library, remove it since that module is now linked in. 1178 StringRef ModuleId = SrcM->getModuleIdentifier(); 1179 if (!ModuleId.empty()) 1180 DstM->removeLibrary(sys::path::stem(ModuleId)); 1181 1182 // Loop over all of the linked values to compute type mappings. 1183 computeTypeMapping(); 1184 1185 // Insert all of the globals in src into the DstM module... without linking 1186 // initializers (which could refer to functions not yet mapped over). 1187 for (Module::global_iterator I = SrcM->global_begin(), 1188 E = SrcM->global_end(); I != E; ++I) 1189 if (linkGlobalProto(I)) 1190 return true; 1191 1192 // Link the functions together between the two modules, without doing function 1193 // bodies... this just adds external function prototypes to the DstM 1194 // function... We do this so that when we begin processing function bodies, 1195 // all of the global values that may be referenced are available in our 1196 // ValueMap. 1197 for (Module::iterator I = SrcM->begin(), E = SrcM->end(); I != E; ++I) 1198 if (linkFunctionProto(I)) 1199 return true; 1200 1201 // If there were any aliases, link them now. 1202 for (Module::alias_iterator I = SrcM->alias_begin(), 1203 E = SrcM->alias_end(); I != E; ++I) 1204 if (linkAliasProto(I)) 1205 return true; 1206 1207 for (unsigned i = 0, e = AppendingVars.size(); i != e; ++i) 1208 linkAppendingVarInit(AppendingVars[i]); 1209 1210 // Update the initializers in the DstM module now that all globals that may 1211 // be referenced are in DstM. 1212 linkGlobalInits(); 1213 1214 // Link in the function bodies that are defined in the source module into 1215 // DstM. 1216 for (Module::iterator SF = SrcM->begin(), E = SrcM->end(); SF != E; ++SF) { 1217 // Skip if not linking from source. 1218 if (DoNotLinkFromSource.count(SF)) continue; 1219 1220 // Skip if no body (function is external) or materialize. 1221 if (SF->isDeclaration()) { 1222 if (!SF->isMaterializable()) 1223 continue; 1224 if (SF->Materialize(&ErrorMsg)) 1225 return true; 1226 } 1227 1228 linkFunctionBody(cast<Function>(ValueMap[SF]), SF); 1229 SF->Dematerialize(); 1230 } 1231 1232 // Resolve all uses of aliases with aliasees. 1233 linkAliasBodies(); 1234 1235 // Remap all of the named MDNodes in Src into the DstM module. We do this 1236 // after linking GlobalValues so that MDNodes that reference GlobalValues 1237 // are properly remapped. 1238 linkNamedMDNodes(); 1239 1240 // Merge the module flags into the DstM module. 1241 if (linkModuleFlagsMetadata()) 1242 return true; 1243 1244 // Process vector of lazily linked in functions. 1245 bool LinkedInAnyFunctions; 1246 do { 1247 LinkedInAnyFunctions = false; 1248 1249 for(std::vector<Function*>::iterator I = LazilyLinkFunctions.begin(), 1250 E = LazilyLinkFunctions.end(); I != E; ++I) { 1251 if (!*I) 1252 continue; 1253 1254 Function *SF = *I; 1255 Function *DF = cast<Function>(ValueMap[SF]); 1256 1257 if (!DF->use_empty()) { 1258 1259 // Materialize if necessary. 1260 if (SF->isDeclaration()) { 1261 if (!SF->isMaterializable()) 1262 continue; 1263 if (SF->Materialize(&ErrorMsg)) 1264 return true; 1265 } 1266 1267 // Link in function body. 1268 linkFunctionBody(DF, SF); 1269 SF->Dematerialize(); 1270 1271 // "Remove" from vector by setting the element to 0. 1272 *I = 0; 1273 1274 // Set flag to indicate we may have more functions to lazily link in 1275 // since we linked in a function. 1276 LinkedInAnyFunctions = true; 1277 } 1278 } 1279 } while (LinkedInAnyFunctions); 1280 1281 // Remove any prototypes of functions that were not actually linked in. 1282 for(std::vector<Function*>::iterator I = LazilyLinkFunctions.begin(), 1283 E = LazilyLinkFunctions.end(); I != E; ++I) { 1284 if (!*I) 1285 continue; 1286 1287 Function *SF = *I; 1288 Function *DF = cast<Function>(ValueMap[SF]); 1289 if (DF->use_empty()) 1290 DF->eraseFromParent(); 1291 } 1292 1293 // Now that all of the types from the source are used, resolve any structs 1294 // copied over to the dest that didn't exist there. 1295 TypeMap.linkDefinedTypeBodies(); 1296 1297 return false; 1298} 1299 1300//===----------------------------------------------------------------------===// 1301// LinkModules entrypoint. 1302//===----------------------------------------------------------------------===// 1303 1304/// LinkModules - This function links two modules together, with the resulting 1305/// left module modified to be the composite of the two input modules. If an 1306/// error occurs, true is returned and ErrorMsg (if not null) is set to indicate 1307/// the problem. Upon failure, the Dest module could be in a modified state, 1308/// and shouldn't be relied on to be consistent. 1309bool Linker::LinkModules(Module *Dest, Module *Src, unsigned Mode, 1310 std::string *ErrorMsg) { 1311 ModuleLinker TheLinker(Dest, Src, Mode); 1312 if (TheLinker.run()) { 1313 if (ErrorMsg) *ErrorMsg = TheLinker.ErrorMsg; 1314 return true; 1315 } 1316 1317 return false; 1318} 1319