LinkModules.cpp revision 2e013028f2dd99527044d50808a44ae89d6ba537
1//===- lib/Linker/LinkModules.cpp - Module Linker Implementation ----------===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file implements the LLVM module linker. 11// 12//===----------------------------------------------------------------------===// 13 14#include "llvm/Linker.h" 15#include "llvm-c/Linker.h" 16#include "llvm/ADT/Optional.h" 17#include "llvm/ADT/SetVector.h" 18#include "llvm/ADT/SmallString.h" 19#include "llvm/IR/Constants.h" 20#include "llvm/IR/Module.h" 21#include "llvm/IR/TypeFinder.h" 22#include "llvm/Support/Debug.h" 23#include "llvm/Support/raw_ostream.h" 24#include "llvm/Transforms/Utils/Cloning.h" 25using namespace llvm; 26 27//===----------------------------------------------------------------------===// 28// TypeMap implementation. 29//===----------------------------------------------------------------------===// 30 31namespace { 32class TypeMapTy : public ValueMapTypeRemapper { 33 /// MappedTypes - This is a mapping from a source type to a destination type 34 /// to use. 35 DenseMap<Type*, Type*> MappedTypes; 36 37 /// SpeculativeTypes - When checking to see if two subgraphs are isomorphic, 38 /// we speculatively add types to MappedTypes, but keep track of them here in 39 /// case we need to roll back. 40 SmallVector<Type*, 16> SpeculativeTypes; 41 42 /// SrcDefinitionsToResolve - This is a list of non-opaque structs in the 43 /// source module that are mapped to an opaque struct in the destination 44 /// module. 45 SmallVector<StructType*, 16> SrcDefinitionsToResolve; 46 47 /// DstResolvedOpaqueTypes - This is the set of opaque types in the 48 /// destination modules who are getting a body from the source module. 49 SmallPtrSet<StructType*, 16> DstResolvedOpaqueTypes; 50 51public: 52 /// addTypeMapping - Indicate that the specified type in the destination 53 /// module is conceptually equivalent to the specified type in the source 54 /// module. 55 void addTypeMapping(Type *DstTy, Type *SrcTy); 56 57 /// linkDefinedTypeBodies - Produce a body for an opaque type in the dest 58 /// module from a type definition in the source module. 59 void linkDefinedTypeBodies(); 60 61 /// get - Return the mapped type to use for the specified input type from the 62 /// source module. 63 Type *get(Type *SrcTy); 64 65 FunctionType *get(FunctionType *T) {return cast<FunctionType>(get((Type*)T));} 66 67 /// dump - Dump out the type map for debugging purposes. 68 void dump() const { 69 for (DenseMap<Type*, Type*>::const_iterator 70 I = MappedTypes.begin(), E = MappedTypes.end(); I != E; ++I) { 71 dbgs() << "TypeMap: "; 72 I->first->dump(); 73 dbgs() << " => "; 74 I->second->dump(); 75 dbgs() << '\n'; 76 } 77 } 78 79private: 80 Type *getImpl(Type *T); 81 /// remapType - Implement the ValueMapTypeRemapper interface. 82 Type *remapType(Type *SrcTy) { 83 return get(SrcTy); 84 } 85 86 bool areTypesIsomorphic(Type *DstTy, Type *SrcTy); 87}; 88} 89 90void TypeMapTy::addTypeMapping(Type *DstTy, Type *SrcTy) { 91 Type *&Entry = MappedTypes[SrcTy]; 92 if (Entry) return; 93 94 if (DstTy == SrcTy) { 95 Entry = DstTy; 96 return; 97 } 98 99 // Check to see if these types are recursively isomorphic and establish a 100 // mapping between them if so. 101 if (!areTypesIsomorphic(DstTy, SrcTy)) { 102 // Oops, they aren't isomorphic. Just discard this request by rolling out 103 // any speculative mappings we've established. 104 for (unsigned i = 0, e = SpeculativeTypes.size(); i != e; ++i) 105 MappedTypes.erase(SpeculativeTypes[i]); 106 } 107 SpeculativeTypes.clear(); 108} 109 110/// areTypesIsomorphic - Recursively walk this pair of types, returning true 111/// if they are isomorphic, false if they are not. 112bool TypeMapTy::areTypesIsomorphic(Type *DstTy, Type *SrcTy) { 113 // Two types with differing kinds are clearly not isomorphic. 114 if (DstTy->getTypeID() != SrcTy->getTypeID()) return false; 115 116 // If we have an entry in the MappedTypes table, then we have our answer. 117 Type *&Entry = MappedTypes[SrcTy]; 118 if (Entry) 119 return Entry == DstTy; 120 121 // Two identical types are clearly isomorphic. Remember this 122 // non-speculatively. 123 if (DstTy == SrcTy) { 124 Entry = DstTy; 125 return true; 126 } 127 128 // Okay, we have two types with identical kinds that we haven't seen before. 129 130 // If this is an opaque struct type, special case it. 131 if (StructType *SSTy = dyn_cast<StructType>(SrcTy)) { 132 // Mapping an opaque type to any struct, just keep the dest struct. 133 if (SSTy->isOpaque()) { 134 Entry = DstTy; 135 SpeculativeTypes.push_back(SrcTy); 136 return true; 137 } 138 139 // Mapping a non-opaque source type to an opaque dest. If this is the first 140 // type that we're mapping onto this destination type then we succeed. Keep 141 // the dest, but fill it in later. This doesn't need to be speculative. If 142 // this is the second (different) type that we're trying to map onto the 143 // same opaque type then we fail. 144 if (cast<StructType>(DstTy)->isOpaque()) { 145 // We can only map one source type onto the opaque destination type. 146 if (!DstResolvedOpaqueTypes.insert(cast<StructType>(DstTy))) 147 return false; 148 SrcDefinitionsToResolve.push_back(SSTy); 149 Entry = DstTy; 150 return true; 151 } 152 } 153 154 // If the number of subtypes disagree between the two types, then we fail. 155 if (SrcTy->getNumContainedTypes() != DstTy->getNumContainedTypes()) 156 return false; 157 158 // Fail if any of the extra properties (e.g. array size) of the type disagree. 159 if (isa<IntegerType>(DstTy)) 160 return false; // bitwidth disagrees. 161 if (PointerType *PT = dyn_cast<PointerType>(DstTy)) { 162 if (PT->getAddressSpace() != cast<PointerType>(SrcTy)->getAddressSpace()) 163 return false; 164 165 } else if (FunctionType *FT = dyn_cast<FunctionType>(DstTy)) { 166 if (FT->isVarArg() != cast<FunctionType>(SrcTy)->isVarArg()) 167 return false; 168 } else if (StructType *DSTy = dyn_cast<StructType>(DstTy)) { 169 StructType *SSTy = cast<StructType>(SrcTy); 170 if (DSTy->isLiteral() != SSTy->isLiteral() || 171 DSTy->isPacked() != SSTy->isPacked()) 172 return false; 173 } else if (ArrayType *DATy = dyn_cast<ArrayType>(DstTy)) { 174 if (DATy->getNumElements() != cast<ArrayType>(SrcTy)->getNumElements()) 175 return false; 176 } else if (VectorType *DVTy = dyn_cast<VectorType>(DstTy)) { 177 if (DVTy->getNumElements() != cast<VectorType>(SrcTy)->getNumElements()) 178 return false; 179 } 180 181 // Otherwise, we speculate that these two types will line up and recursively 182 // check the subelements. 183 Entry = DstTy; 184 SpeculativeTypes.push_back(SrcTy); 185 186 for (unsigned i = 0, e = SrcTy->getNumContainedTypes(); i != e; ++i) 187 if (!areTypesIsomorphic(DstTy->getContainedType(i), 188 SrcTy->getContainedType(i))) 189 return false; 190 191 // If everything seems to have lined up, then everything is great. 192 return true; 193} 194 195/// linkDefinedTypeBodies - Produce a body for an opaque type in the dest 196/// module from a type definition in the source module. 197void TypeMapTy::linkDefinedTypeBodies() { 198 SmallVector<Type*, 16> Elements; 199 SmallString<16> TmpName; 200 201 // Note that processing entries in this loop (calling 'get') can add new 202 // entries to the SrcDefinitionsToResolve vector. 203 while (!SrcDefinitionsToResolve.empty()) { 204 StructType *SrcSTy = SrcDefinitionsToResolve.pop_back_val(); 205 StructType *DstSTy = cast<StructType>(MappedTypes[SrcSTy]); 206 207 // TypeMap is a many-to-one mapping, if there were multiple types that 208 // provide a body for DstSTy then previous iterations of this loop may have 209 // already handled it. Just ignore this case. 210 if (!DstSTy->isOpaque()) continue; 211 assert(!SrcSTy->isOpaque() && "Not resolving a definition?"); 212 213 // Map the body of the source type over to a new body for the dest type. 214 Elements.resize(SrcSTy->getNumElements()); 215 for (unsigned i = 0, e = Elements.size(); i != e; ++i) 216 Elements[i] = getImpl(SrcSTy->getElementType(i)); 217 218 DstSTy->setBody(Elements, SrcSTy->isPacked()); 219 220 // If DstSTy has no name or has a longer name than STy, then viciously steal 221 // STy's name. 222 if (!SrcSTy->hasName()) continue; 223 StringRef SrcName = SrcSTy->getName(); 224 225 if (!DstSTy->hasName() || DstSTy->getName().size() > SrcName.size()) { 226 TmpName.insert(TmpName.end(), SrcName.begin(), SrcName.end()); 227 SrcSTy->setName(""); 228 DstSTy->setName(TmpName.str()); 229 TmpName.clear(); 230 } 231 } 232 233 DstResolvedOpaqueTypes.clear(); 234} 235 236/// get - Return the mapped type to use for the specified input type from the 237/// source module. 238Type *TypeMapTy::get(Type *Ty) { 239 Type *Result = getImpl(Ty); 240 241 // If this caused a reference to any struct type, resolve it before returning. 242 if (!SrcDefinitionsToResolve.empty()) 243 linkDefinedTypeBodies(); 244 return Result; 245} 246 247/// getImpl - This is the recursive version of get(). 248Type *TypeMapTy::getImpl(Type *Ty) { 249 // If we already have an entry for this type, return it. 250 Type **Entry = &MappedTypes[Ty]; 251 if (*Entry) return *Entry; 252 253 // If this is not a named struct type, then just map all of the elements and 254 // then rebuild the type from inside out. 255 if (!isa<StructType>(Ty) || cast<StructType>(Ty)->isLiteral()) { 256 // If there are no element types to map, then the type is itself. This is 257 // true for the anonymous {} struct, things like 'float', integers, etc. 258 if (Ty->getNumContainedTypes() == 0) 259 return *Entry = Ty; 260 261 // Remap all of the elements, keeping track of whether any of them change. 262 bool AnyChange = false; 263 SmallVector<Type*, 4> ElementTypes; 264 ElementTypes.resize(Ty->getNumContainedTypes()); 265 for (unsigned i = 0, e = Ty->getNumContainedTypes(); i != e; ++i) { 266 ElementTypes[i] = getImpl(Ty->getContainedType(i)); 267 AnyChange |= ElementTypes[i] != Ty->getContainedType(i); 268 } 269 270 // If we found our type while recursively processing stuff, just use it. 271 Entry = &MappedTypes[Ty]; 272 if (*Entry) return *Entry; 273 274 // If all of the element types mapped directly over, then the type is usable 275 // as-is. 276 if (!AnyChange) 277 return *Entry = Ty; 278 279 // Otherwise, rebuild a modified type. 280 switch (Ty->getTypeID()) { 281 default: llvm_unreachable("unknown derived type to remap"); 282 case Type::ArrayTyID: 283 return *Entry = ArrayType::get(ElementTypes[0], 284 cast<ArrayType>(Ty)->getNumElements()); 285 case Type::VectorTyID: 286 return *Entry = VectorType::get(ElementTypes[0], 287 cast<VectorType>(Ty)->getNumElements()); 288 case Type::PointerTyID: 289 return *Entry = PointerType::get(ElementTypes[0], 290 cast<PointerType>(Ty)->getAddressSpace()); 291 case Type::FunctionTyID: 292 return *Entry = FunctionType::get(ElementTypes[0], 293 makeArrayRef(ElementTypes).slice(1), 294 cast<FunctionType>(Ty)->isVarArg()); 295 case Type::StructTyID: 296 // Note that this is only reached for anonymous structs. 297 return *Entry = StructType::get(Ty->getContext(), ElementTypes, 298 cast<StructType>(Ty)->isPacked()); 299 } 300 } 301 302 // Otherwise, this is an unmapped named struct. If the struct can be directly 303 // mapped over, just use it as-is. This happens in a case when the linked-in 304 // module has something like: 305 // %T = type {%T*, i32} 306 // @GV = global %T* null 307 // where T does not exist at all in the destination module. 308 // 309 // The other case we watch for is when the type is not in the destination 310 // module, but that it has to be rebuilt because it refers to something that 311 // is already mapped. For example, if the destination module has: 312 // %A = type { i32 } 313 // and the source module has something like 314 // %A' = type { i32 } 315 // %B = type { %A'* } 316 // @GV = global %B* null 317 // then we want to create a new type: "%B = type { %A*}" and have it take the 318 // pristine "%B" name from the source module. 319 // 320 // To determine which case this is, we have to recursively walk the type graph 321 // speculating that we'll be able to reuse it unmodified. Only if this is 322 // safe would we map the entire thing over. Because this is an optimization, 323 // and is not required for the prettiness of the linked module, we just skip 324 // it and always rebuild a type here. 325 StructType *STy = cast<StructType>(Ty); 326 327 // If the type is opaque, we can just use it directly. 328 if (STy->isOpaque()) 329 return *Entry = STy; 330 331 // Otherwise we create a new type and resolve its body later. This will be 332 // resolved by the top level of get(). 333 SrcDefinitionsToResolve.push_back(STy); 334 StructType *DTy = StructType::create(STy->getContext()); 335 DstResolvedOpaqueTypes.insert(DTy); 336 return *Entry = DTy; 337} 338 339//===----------------------------------------------------------------------===// 340// ModuleLinker implementation. 341//===----------------------------------------------------------------------===// 342 343namespace { 344 /// ModuleLinker - This is an implementation class for the LinkModules 345 /// function, which is the entrypoint for this file. 346 class ModuleLinker { 347 Module *DstM, *SrcM; 348 349 TypeMapTy TypeMap; 350 351 /// ValueMap - Mapping of values from what they used to be in Src, to what 352 /// they are now in DstM. ValueToValueMapTy is a ValueMap, which involves 353 /// some overhead due to the use of Value handles which the Linker doesn't 354 /// actually need, but this allows us to reuse the ValueMapper code. 355 ValueToValueMapTy ValueMap; 356 357 struct AppendingVarInfo { 358 GlobalVariable *NewGV; // New aggregate global in dest module. 359 Constant *DstInit; // Old initializer from dest module. 360 Constant *SrcInit; // Old initializer from src module. 361 }; 362 363 std::vector<AppendingVarInfo> AppendingVars; 364 365 unsigned Mode; // Mode to treat source module. 366 367 // Set of items not to link in from source. 368 SmallPtrSet<const Value*, 16> DoNotLinkFromSource; 369 370 // Vector of functions to lazily link in. 371 std::vector<Function*> LazilyLinkFunctions; 372 373 public: 374 std::string ErrorMsg; 375 376 ModuleLinker(Module *dstM, Module *srcM, unsigned mode) 377 : DstM(dstM), SrcM(srcM), Mode(mode) { } 378 379 bool run(); 380 381 private: 382 /// emitError - Helper method for setting a message and returning an error 383 /// code. 384 bool emitError(const Twine &Message) { 385 ErrorMsg = Message.str(); 386 return true; 387 } 388 389 /// getLinkageResult - This analyzes the two global values and determines 390 /// what the result will look like in the destination module. 391 bool getLinkageResult(GlobalValue *Dest, const GlobalValue *Src, 392 GlobalValue::LinkageTypes <, 393 GlobalValue::VisibilityTypes &Vis, 394 bool &LinkFromSrc); 395 396 /// getLinkedToGlobal - Given a global in the source module, return the 397 /// global in the destination module that is being linked to, if any. 398 GlobalValue *getLinkedToGlobal(GlobalValue *SrcGV) { 399 // If the source has no name it can't link. If it has local linkage, 400 // there is no name match-up going on. 401 if (!SrcGV->hasName() || SrcGV->hasLocalLinkage()) 402 return 0; 403 404 // Otherwise see if we have a match in the destination module's symtab. 405 GlobalValue *DGV = DstM->getNamedValue(SrcGV->getName()); 406 if (DGV == 0) return 0; 407 408 // If we found a global with the same name in the dest module, but it has 409 // internal linkage, we are really not doing any linkage here. 410 if (DGV->hasLocalLinkage()) 411 return 0; 412 413 // Otherwise, we do in fact link to the destination global. 414 return DGV; 415 } 416 417 void computeTypeMapping(); 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/// forceRenaming - The LLVM SymbolTable class autorenames globals that conflict 434/// in the symbol table. This is good for all clients except for us. Go 435/// through the trouble to force this back. 436static void forceRenaming(GlobalValue *GV, StringRef Name) { 437 // If the global doesn't force its name or if it already has the right name, 438 // there is nothing for us to do. 439 if (GV->hasLocalLinkage() || GV->getName() == Name) 440 return; 441 442 Module *M = GV->getParent(); 443 444 // If there is a conflict, rename the conflict. 445 if (GlobalValue *ConflictGV = M->getNamedValue(Name)) { 446 GV->takeName(ConflictGV); 447 ConflictGV->setName(Name); // This will cause ConflictGV to get renamed 448 assert(ConflictGV->getName() != Name && "forceRenaming didn't work"); 449 } else { 450 GV->setName(Name); // Force the name back 451 } 452} 453 454/// copyGVAttributes - copy additional attributes (those not needed to construct 455/// a GlobalValue) from the SrcGV to the DestGV. 456static void copyGVAttributes(GlobalValue *DestGV, const GlobalValue *SrcGV) { 457 // Use the maximum alignment, rather than just copying the alignment of SrcGV. 458 unsigned Alignment = std::max(DestGV->getAlignment(), SrcGV->getAlignment()); 459 DestGV->copyAttributesFrom(SrcGV); 460 DestGV->setAlignment(Alignment); 461 462 forceRenaming(DestGV, SrcGV->getName()); 463} 464 465static bool isLessConstraining(GlobalValue::VisibilityTypes a, 466 GlobalValue::VisibilityTypes b) { 467 if (a == GlobalValue::HiddenVisibility) 468 return false; 469 if (b == GlobalValue::HiddenVisibility) 470 return true; 471 if (a == GlobalValue::ProtectedVisibility) 472 return false; 473 if (b == GlobalValue::ProtectedVisibility) 474 return true; 475 return false; 476} 477 478/// getLinkageResult - This analyzes the two global values and determines what 479/// the result will look like in the destination module. In particular, it 480/// computes the resultant linkage type and visibility, computes whether the 481/// global in the source should be copied over to the destination (replacing 482/// the existing one), and computes whether this linkage is an error or not. 483bool ModuleLinker::getLinkageResult(GlobalValue *Dest, const GlobalValue *Src, 484 GlobalValue::LinkageTypes <, 485 GlobalValue::VisibilityTypes &Vis, 486 bool &LinkFromSrc) { 487 assert(Dest && "Must have two globals being queried"); 488 assert(!Src->hasLocalLinkage() && 489 "If Src has internal linkage, Dest shouldn't be set!"); 490 491 bool SrcIsDeclaration = Src->isDeclaration() && !Src->isMaterializable(); 492 bool DestIsDeclaration = Dest->isDeclaration(); 493 494 if (SrcIsDeclaration) { 495 // If Src is external or if both Src & Dest are external.. Just link the 496 // external globals, we aren't adding anything. 497 if (Src->hasDLLImportLinkage()) { 498 // If one of GVs has DLLImport linkage, result should be dllimport'ed. 499 if (DestIsDeclaration) { 500 LinkFromSrc = true; 501 LT = Src->getLinkage(); 502 } 503 } else if (Dest->hasExternalWeakLinkage()) { 504 // If the Dest is weak, use the source linkage. 505 LinkFromSrc = true; 506 LT = Src->getLinkage(); 507 } else { 508 LinkFromSrc = false; 509 LT = Dest->getLinkage(); 510 } 511 } else if (DestIsDeclaration && !Dest->hasDLLImportLinkage()) { 512 // If Dest is external but Src is not: 513 LinkFromSrc = true; 514 LT = Src->getLinkage(); 515 } else if (Src->isWeakForLinker()) { 516 // At this point we know that Dest has LinkOnce, External*, Weak, Common, 517 // or DLL* linkage. 518 if (Dest->hasExternalWeakLinkage() || 519 Dest->hasAvailableExternallyLinkage() || 520 (Dest->hasLinkOnceLinkage() && 521 (Src->hasWeakLinkage() || Src->hasCommonLinkage()))) { 522 LinkFromSrc = true; 523 LT = Src->getLinkage(); 524 } else { 525 LinkFromSrc = false; 526 LT = Dest->getLinkage(); 527 } 528 } else if (Dest->isWeakForLinker()) { 529 // At this point we know that Src has External* or DLL* linkage. 530 if (Src->hasExternalWeakLinkage()) { 531 LinkFromSrc = false; 532 LT = Dest->getLinkage(); 533 } else { 534 LinkFromSrc = true; 535 LT = GlobalValue::ExternalLinkage; 536 } 537 } else { 538 assert((Dest->hasExternalLinkage() || Dest->hasDLLImportLinkage() || 539 Dest->hasDLLExportLinkage() || Dest->hasExternalWeakLinkage()) && 540 (Src->hasExternalLinkage() || Src->hasDLLImportLinkage() || 541 Src->hasDLLExportLinkage() || Src->hasExternalWeakLinkage()) && 542 "Unexpected linkage type!"); 543 return emitError("Linking globals named '" + Src->getName() + 544 "': symbol multiply defined!"); 545 } 546 547 // Compute the visibility. We follow the rules in the System V Application 548 // Binary Interface. 549 Vis = isLessConstraining(Src->getVisibility(), Dest->getVisibility()) ? 550 Dest->getVisibility() : Src->getVisibility(); 551 return false; 552} 553 554/// computeTypeMapping - Loop over all of the linked values to compute type 555/// mappings. For example, if we link "extern Foo *x" and "Foo *x = NULL", then 556/// we have two struct types 'Foo' but one got renamed when the module was 557/// loaded into the same LLVMContext. 558void ModuleLinker::computeTypeMapping() { 559 // Incorporate globals. 560 for (Module::global_iterator I = SrcM->global_begin(), 561 E = SrcM->global_end(); I != E; ++I) { 562 GlobalValue *DGV = getLinkedToGlobal(I); 563 if (DGV == 0) continue; 564 565 if (!DGV->hasAppendingLinkage() || !I->hasAppendingLinkage()) { 566 TypeMap.addTypeMapping(DGV->getType(), I->getType()); 567 continue; 568 } 569 570 // Unify the element type of appending arrays. 571 ArrayType *DAT = cast<ArrayType>(DGV->getType()->getElementType()); 572 ArrayType *SAT = cast<ArrayType>(I->getType()->getElementType()); 573 TypeMap.addTypeMapping(DAT->getElementType(), SAT->getElementType()); 574 } 575 576 // Incorporate functions. 577 for (Module::iterator I = SrcM->begin(), E = SrcM->end(); I != E; ++I) { 578 if (GlobalValue *DGV = getLinkedToGlobal(I)) 579 TypeMap.addTypeMapping(DGV->getType(), I->getType()); 580 } 581 582 // Incorporate types by name, scanning all the types in the source module. 583 // At this point, the destination module may have a type "%foo = { i32 }" for 584 // example. When the source module got loaded into the same LLVMContext, if 585 // it had the same type, it would have been renamed to "%foo.42 = { i32 }". 586 TypeFinder SrcStructTypes; 587 SrcStructTypes.run(*SrcM, true); 588 SmallPtrSet<StructType*, 32> SrcStructTypesSet(SrcStructTypes.begin(), 589 SrcStructTypes.end()); 590 591 TypeFinder DstStructTypes; 592 DstStructTypes.run(*DstM, true); 593 SmallPtrSet<StructType*, 32> DstStructTypesSet(DstStructTypes.begin(), 594 DstStructTypes.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() == '.' || 604 !isdigit(static_cast<unsigned char>(ST->getName()[DotPos+1]))) 605 continue; 606 607 // Check to see if the destination module has a struct with the prefix name. 608 if (StructType *DST = DstM->getTypeByName(ST->getName().substr(0, DotPos))) 609 // Don't use it if this actually came from the source module. They're in 610 // the same LLVMContext after all. Also don't use it unless the type is 611 // actually used in the destination module. This can happen in situations 612 // like this: 613 // 614 // Module A Module B 615 // -------- -------- 616 // %Z = type { %A } %B = type { %C.1 } 617 // %A = type { %B.1, [7 x i8] } %C.1 = type { i8* } 618 // %B.1 = type { %C } %A.2 = type { %B.3, [5 x i8] } 619 // %C = type { i8* } %B.3 = type { %C.1 } 620 // 621 // When we link Module B with Module A, the '%B' in Module B is 622 // used. However, that would then use '%C.1'. But when we process '%C.1', 623 // we prefer to take the '%C' version. So we are then left with both 624 // '%C.1' and '%C' being used for the same types. This leads to some 625 // variables using one type and some using the other. 626 if (!SrcStructTypesSet.count(DST) && DstStructTypesSet.count(DST)) 627 TypeMap.addTypeMapping(DST, ST); 628 } 629 630 // Don't bother incorporating aliases, they aren't generally typed well. 631 632 // Now that we have discovered all of the type equivalences, get a body for 633 // any 'opaque' types in the dest module that are now resolved. 634 TypeMap.linkDefinedTypeBodies(); 635} 636 637/// linkAppendingVarProto - If there were any appending global variables, link 638/// them together now. Return true on error. 639bool ModuleLinker::linkAppendingVarProto(GlobalVariable *DstGV, 640 GlobalVariable *SrcGV) { 641 642 if (!SrcGV->hasAppendingLinkage() || !DstGV->hasAppendingLinkage()) 643 return emitError("Linking globals named '" + SrcGV->getName() + 644 "': can only link appending global with another appending global!"); 645 646 ArrayType *DstTy = cast<ArrayType>(DstGV->getType()->getElementType()); 647 ArrayType *SrcTy = 648 cast<ArrayType>(TypeMap.get(SrcGV->getType()->getElementType())); 649 Type *EltTy = DstTy->getElementType(); 650 651 // Check to see that they two arrays agree on type. 652 if (EltTy != SrcTy->getElementType()) 653 return emitError("Appending variables with different element types!"); 654 if (DstGV->isConstant() != SrcGV->isConstant()) 655 return emitError("Appending variables linked with different const'ness!"); 656 657 if (DstGV->getAlignment() != SrcGV->getAlignment()) 658 return emitError( 659 "Appending variables with different alignment need to be linked!"); 660 661 if (DstGV->getVisibility() != SrcGV->getVisibility()) 662 return emitError( 663 "Appending variables with different visibility need to be linked!"); 664 665 if (DstGV->getSection() != SrcGV->getSection()) 666 return emitError( 667 "Appending variables with different section name need to be linked!"); 668 669 uint64_t NewSize = DstTy->getNumElements() + SrcTy->getNumElements(); 670 ArrayType *NewType = ArrayType::get(EltTy, NewSize); 671 672 // Create the new global variable. 673 GlobalVariable *NG = 674 new GlobalVariable(*DstGV->getParent(), NewType, SrcGV->isConstant(), 675 DstGV->getLinkage(), /*init*/0, /*name*/"", DstGV, 676 DstGV->getThreadLocalMode(), 677 DstGV->getType()->getAddressSpace()); 678 679 // Propagate alignment, visibility and section info. 680 copyGVAttributes(NG, DstGV); 681 682 AppendingVarInfo AVI; 683 AVI.NewGV = NG; 684 AVI.DstInit = DstGV->getInitializer(); 685 AVI.SrcInit = SrcGV->getInitializer(); 686 AppendingVars.push_back(AVI); 687 688 // Replace any uses of the two global variables with uses of the new 689 // global. 690 ValueMap[SrcGV] = ConstantExpr::getBitCast(NG, TypeMap.get(SrcGV->getType())); 691 692 DstGV->replaceAllUsesWith(ConstantExpr::getBitCast(NG, DstGV->getType())); 693 DstGV->eraseFromParent(); 694 695 // Track the source variable so we don't try to link it. 696 DoNotLinkFromSource.insert(SrcGV); 697 698 return false; 699} 700 701/// linkGlobalProto - Loop through the global variables in the src module and 702/// merge them into the dest module. 703bool ModuleLinker::linkGlobalProto(GlobalVariable *SGV) { 704 GlobalValue *DGV = getLinkedToGlobal(SGV); 705 llvm::Optional<GlobalValue::VisibilityTypes> NewVisibility; 706 707 if (DGV) { 708 // Concatenation of appending linkage variables is magic and handled later. 709 if (DGV->hasAppendingLinkage() || SGV->hasAppendingLinkage()) 710 return linkAppendingVarProto(cast<GlobalVariable>(DGV), SGV); 711 712 // Determine whether linkage of these two globals follows the source 713 // module's definition or the destination module's definition. 714 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; 715 GlobalValue::VisibilityTypes NV; 716 bool LinkFromSrc = false; 717 if (getLinkageResult(DGV, SGV, NewLinkage, NV, LinkFromSrc)) 718 return true; 719 NewVisibility = NV; 720 721 // If we're not linking from the source, then keep the definition that we 722 // have. 723 if (!LinkFromSrc) { 724 // Special case for const propagation. 725 if (GlobalVariable *DGVar = dyn_cast<GlobalVariable>(DGV)) 726 if (DGVar->isDeclaration() && SGV->isConstant() && !DGVar->isConstant()) 727 DGVar->setConstant(true); 728 729 // Set calculated linkage and visibility. 730 DGV->setLinkage(NewLinkage); 731 DGV->setVisibility(*NewVisibility); 732 733 // Make sure to remember this mapping. 734 ValueMap[SGV] = ConstantExpr::getBitCast(DGV,TypeMap.get(SGV->getType())); 735 736 // Track the source global so that we don't attempt to copy it over when 737 // processing global initializers. 738 DoNotLinkFromSource.insert(SGV); 739 740 return false; 741 } 742 } 743 744 // No linking to be performed or linking from the source: simply create an 745 // identical version of the symbol over in the dest module... the 746 // initializer will be filled in later by LinkGlobalInits. 747 GlobalVariable *NewDGV = 748 new GlobalVariable(*DstM, TypeMap.get(SGV->getType()->getElementType()), 749 SGV->isConstant(), SGV->getLinkage(), /*init*/0, 750 SGV->getName(), /*insertbefore*/0, 751 SGV->getThreadLocalMode(), 752 SGV->getType()->getAddressSpace()); 753 // Propagate alignment, visibility and section info. 754 copyGVAttributes(NewDGV, SGV); 755 if (NewVisibility) 756 NewDGV->setVisibility(*NewVisibility); 757 758 if (DGV) { 759 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDGV, DGV->getType())); 760 DGV->eraseFromParent(); 761 } 762 763 // Make sure to remember this mapping. 764 ValueMap[SGV] = NewDGV; 765 return false; 766} 767 768/// linkFunctionProto - Link the function in the source module into the 769/// destination module if needed, setting up mapping information. 770bool ModuleLinker::linkFunctionProto(Function *SF) { 771 GlobalValue *DGV = getLinkedToGlobal(SF); 772 llvm::Optional<GlobalValue::VisibilityTypes> NewVisibility; 773 774 if (DGV) { 775 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; 776 bool LinkFromSrc = false; 777 GlobalValue::VisibilityTypes NV; 778 if (getLinkageResult(DGV, SF, NewLinkage, NV, LinkFromSrc)) 779 return true; 780 NewVisibility = NV; 781 782 if (!LinkFromSrc) { 783 // Set calculated linkage 784 DGV->setLinkage(NewLinkage); 785 DGV->setVisibility(*NewVisibility); 786 787 // Make sure to remember this mapping. 788 ValueMap[SF] = ConstantExpr::getBitCast(DGV, TypeMap.get(SF->getType())); 789 790 // Track the function from the source module so we don't attempt to remap 791 // it. 792 DoNotLinkFromSource.insert(SF); 793 794 return false; 795 } 796 } 797 798 // If there is no linkage to be performed or we are linking from the source, 799 // bring SF over. 800 Function *NewDF = Function::Create(TypeMap.get(SF->getFunctionType()), 801 SF->getLinkage(), SF->getName(), DstM); 802 copyGVAttributes(NewDF, SF); 803 if (NewVisibility) 804 NewDF->setVisibility(*NewVisibility); 805 806 if (DGV) { 807 // Any uses of DF need to change to NewDF, with cast. 808 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDF, DGV->getType())); 809 DGV->eraseFromParent(); 810 } else { 811 // Internal, LO_ODR, or LO linkage - stick in set to ignore and lazily link. 812 if (SF->hasLocalLinkage() || SF->hasLinkOnceLinkage() || 813 SF->hasAvailableExternallyLinkage()) { 814 DoNotLinkFromSource.insert(SF); 815 LazilyLinkFunctions.push_back(SF); 816 } 817 } 818 819 ValueMap[SF] = NewDF; 820 return false; 821} 822 823/// LinkAliasProto - Set up prototypes for any aliases that come over from the 824/// source module. 825bool ModuleLinker::linkAliasProto(GlobalAlias *SGA) { 826 GlobalValue *DGV = getLinkedToGlobal(SGA); 827 llvm::Optional<GlobalValue::VisibilityTypes> NewVisibility; 828 829 if (DGV) { 830 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; 831 GlobalValue::VisibilityTypes NV; 832 bool LinkFromSrc = false; 833 if (getLinkageResult(DGV, SGA, NewLinkage, NV, LinkFromSrc)) 834 return true; 835 NewVisibility = NV; 836 837 if (!LinkFromSrc) { 838 // Set calculated linkage. 839 DGV->setLinkage(NewLinkage); 840 DGV->setVisibility(*NewVisibility); 841 842 // Make sure to remember this mapping. 843 ValueMap[SGA] = ConstantExpr::getBitCast(DGV,TypeMap.get(SGA->getType())); 844 845 // Track the alias from the source module so we don't attempt to remap it. 846 DoNotLinkFromSource.insert(SGA); 847 848 return false; 849 } 850 } 851 852 // If there is no linkage to be performed or we're linking from the source, 853 // bring over SGA. 854 GlobalAlias *NewDA = new GlobalAlias(TypeMap.get(SGA->getType()), 855 SGA->getLinkage(), SGA->getName(), 856 /*aliasee*/0, DstM); 857 copyGVAttributes(NewDA, SGA); 858 if (NewVisibility) 859 NewDA->setVisibility(*NewVisibility); 860 861 if (DGV) { 862 // Any uses of DGV need to change to NewDA, with cast. 863 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDA, DGV->getType())); 864 DGV->eraseFromParent(); 865 } 866 867 ValueMap[SGA] = NewDA; 868 return false; 869} 870 871static void getArrayElements(Constant *C, SmallVectorImpl<Constant*> &Dest) { 872 unsigned NumElements = cast<ArrayType>(C->getType())->getNumElements(); 873 874 for (unsigned i = 0; i != NumElements; ++i) 875 Dest.push_back(C->getAggregateElement(i)); 876} 877 878void ModuleLinker::linkAppendingVarInit(const AppendingVarInfo &AVI) { 879 // Merge the initializer. 880 SmallVector<Constant*, 16> Elements; 881 getArrayElements(AVI.DstInit, Elements); 882 883 Constant *SrcInit = MapValue(AVI.SrcInit, ValueMap, RF_None, &TypeMap); 884 getArrayElements(SrcInit, Elements); 885 886 ArrayType *NewType = cast<ArrayType>(AVI.NewGV->getType()->getElementType()); 887 AVI.NewGV->setInitializer(ConstantArray::get(NewType, Elements)); 888} 889 890/// linkGlobalInits - Update the initializers in the Dest module now that all 891/// globals that may be referenced are in Dest. 892void ModuleLinker::linkGlobalInits() { 893 // Loop over all of the globals in the src module, mapping them over as we go 894 for (Module::const_global_iterator I = SrcM->global_begin(), 895 E = SrcM->global_end(); I != E; ++I) { 896 897 // Only process initialized GV's or ones not already in dest. 898 if (!I->hasInitializer() || DoNotLinkFromSource.count(I)) continue; 899 900 // Grab destination global variable. 901 GlobalVariable *DGV = cast<GlobalVariable>(ValueMap[I]); 902 // Figure out what the initializer looks like in the dest module. 903 DGV->setInitializer(MapValue(I->getInitializer(), ValueMap, 904 RF_None, &TypeMap)); 905 } 906} 907 908/// linkFunctionBody - Copy the source function over into the dest function and 909/// fix up references to values. At this point we know that Dest is an external 910/// function, and that Src is not. 911void ModuleLinker::linkFunctionBody(Function *Dst, Function *Src) { 912 assert(Src && Dst && Dst->isDeclaration() && !Src->isDeclaration()); 913 914 // Go through and convert function arguments over, remembering the mapping. 915 Function::arg_iterator DI = Dst->arg_begin(); 916 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end(); 917 I != E; ++I, ++DI) { 918 DI->setName(I->getName()); // Copy the name over. 919 920 // Add a mapping to our mapping. 921 ValueMap[I] = DI; 922 } 923 924 if (Mode == Linker::DestroySource) { 925 // Splice the body of the source function into the dest function. 926 Dst->getBasicBlockList().splice(Dst->end(), Src->getBasicBlockList()); 927 928 // At this point, all of the instructions and values of the function are now 929 // copied over. The only problem is that they are still referencing values in 930 // the Source function as operands. Loop through all of the operands of the 931 // functions and patch them up to point to the local versions. 932 for (Function::iterator BB = Dst->begin(), BE = Dst->end(); BB != BE; ++BB) 933 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) 934 RemapInstruction(I, ValueMap, RF_IgnoreMissingEntries, &TypeMap); 935 936 } else { 937 // Clone the body of the function into the dest function. 938 SmallVector<ReturnInst*, 8> Returns; // Ignore returns. 939 CloneFunctionInto(Dst, Src, ValueMap, false, Returns, "", NULL, &TypeMap); 940 } 941 942 // There is no need to map the arguments anymore. 943 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end(); 944 I != E; ++I) 945 ValueMap.erase(I); 946 947} 948 949/// linkAliasBodies - Insert all of the aliases in Src into the Dest module. 950void ModuleLinker::linkAliasBodies() { 951 for (Module::alias_iterator I = SrcM->alias_begin(), E = SrcM->alias_end(); 952 I != E; ++I) { 953 if (DoNotLinkFromSource.count(I)) 954 continue; 955 if (Constant *Aliasee = I->getAliasee()) { 956 GlobalAlias *DA = cast<GlobalAlias>(ValueMap[I]); 957 DA->setAliasee(MapValue(Aliasee, ValueMap, RF_None, &TypeMap)); 958 } 959 } 960} 961 962/// linkNamedMDNodes - Insert all of the named MDNodes in Src into the Dest 963/// module. 964void ModuleLinker::linkNamedMDNodes() { 965 const NamedMDNode *SrcModFlags = SrcM->getModuleFlagsMetadata(); 966 for (Module::const_named_metadata_iterator I = SrcM->named_metadata_begin(), 967 E = SrcM->named_metadata_end(); I != E; ++I) { 968 // Don't link module flags here. Do them separately. 969 if (&*I == SrcModFlags) continue; 970 NamedMDNode *DestNMD = DstM->getOrInsertNamedMetadata(I->getName()); 971 // Add Src elements into Dest node. 972 for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) 973 DestNMD->addOperand(MapValue(I->getOperand(i), ValueMap, 974 RF_None, &TypeMap)); 975 } 976} 977 978/// linkModuleFlagsMetadata - Merge the linker flags in Src into the Dest 979/// module. 980bool ModuleLinker::linkModuleFlagsMetadata() { 981 // If the source module has no module flags, we are done. 982 const NamedMDNode *SrcModFlags = SrcM->getModuleFlagsMetadata(); 983 if (!SrcModFlags) return false; 984 985 // If the destination module doesn't have module flags yet, then just copy 986 // over the source module's flags. 987 NamedMDNode *DstModFlags = DstM->getOrInsertModuleFlagsMetadata(); 988 if (DstModFlags->getNumOperands() == 0) { 989 for (unsigned I = 0, E = SrcModFlags->getNumOperands(); I != E; ++I) 990 DstModFlags->addOperand(SrcModFlags->getOperand(I)); 991 992 return false; 993 } 994 995 // First build a map of the existing module flags and requirements. 996 DenseMap<MDString*, MDNode*> Flags; 997 SmallSetVector<MDNode*, 16> Requirements; 998 for (unsigned I = 0, E = DstModFlags->getNumOperands(); I != E; ++I) { 999 MDNode *Op = DstModFlags->getOperand(I); 1000 ConstantInt *Behavior = cast<ConstantInt>(Op->getOperand(0)); 1001 MDString *ID = cast<MDString>(Op->getOperand(1)); 1002 1003 if (Behavior->getZExtValue() == Module::Require) { 1004 Requirements.insert(cast<MDNode>(Op->getOperand(2))); 1005 } else { 1006 Flags[ID] = Op; 1007 } 1008 } 1009 1010 // Merge in the flags from the source module, and also collect its set of 1011 // requirements. 1012 bool HasErr = false; 1013 for (unsigned I = 0, E = SrcModFlags->getNumOperands(); I != E; ++I) { 1014 MDNode *SrcOp = SrcModFlags->getOperand(I); 1015 ConstantInt *SrcBehavior = cast<ConstantInt>(SrcOp->getOperand(0)); 1016 MDString *ID = cast<MDString>(SrcOp->getOperand(1)); 1017 MDNode *DstOp = Flags.lookup(ID); 1018 unsigned SrcBehaviorValue = SrcBehavior->getZExtValue(); 1019 1020 // If this is a requirement, add it and continue. 1021 if (SrcBehaviorValue == Module::Require) { 1022 // If the destination module does not already have this requirement, add 1023 // it. 1024 if (Requirements.insert(cast<MDNode>(SrcOp->getOperand(2)))) { 1025 DstModFlags->addOperand(SrcOp); 1026 } 1027 continue; 1028 } 1029 1030 // If there is no existing flag with this ID, just add it. 1031 if (!DstOp) { 1032 Flags[ID] = SrcOp; 1033 DstModFlags->addOperand(SrcOp); 1034 continue; 1035 } 1036 1037 // Otherwise, perform a merge. 1038 ConstantInt *DstBehavior = cast<ConstantInt>(DstOp->getOperand(0)); 1039 unsigned DstBehaviorValue = DstBehavior->getZExtValue(); 1040 1041 // If either flag has override behavior, handle it first. 1042 if (DstBehaviorValue == Module::Override) { 1043 // Diagnose inconsistent flags which both have override behavior. 1044 if (SrcBehaviorValue == Module::Override && 1045 SrcOp->getOperand(2) != DstOp->getOperand(2)) { 1046 HasErr |= emitError("linking module flags '" + ID->getString() + 1047 "': IDs have conflicting override values"); 1048 } 1049 continue; 1050 } else if (SrcBehaviorValue == Module::Override) { 1051 // Update the destination flag to that of the source. 1052 DstOp->replaceOperandWith(0, SrcBehavior); 1053 DstOp->replaceOperandWith(2, SrcOp->getOperand(2)); 1054 continue; 1055 } 1056 1057 // Diagnose inconsistent merge behavior types. 1058 if (SrcBehaviorValue != DstBehaviorValue) { 1059 HasErr |= emitError("linking module flags '" + ID->getString() + 1060 "': IDs have conflicting behaviors"); 1061 continue; 1062 } 1063 1064 // Perform the merge for standard behavior types. 1065 switch (SrcBehaviorValue) { 1066 case Module::Require: 1067 case Module::Override: assert(0 && "not possible"); break; 1068 case Module::Error: { 1069 // Emit an error if the values differ. 1070 if (SrcOp->getOperand(2) != DstOp->getOperand(2)) { 1071 HasErr |= emitError("linking module flags '" + ID->getString() + 1072 "': IDs have conflicting values"); 1073 } 1074 continue; 1075 } 1076 case Module::Warning: { 1077 // Emit a warning if the values differ. 1078 if (SrcOp->getOperand(2) != DstOp->getOperand(2)) { 1079 errs() << "WARNING: linking module flags '" << ID->getString() 1080 << "': IDs have conflicting values"; 1081 } 1082 continue; 1083 } 1084 case Module::Append: { 1085 MDNode *DstValue = cast<MDNode>(DstOp->getOperand(2)); 1086 MDNode *SrcValue = cast<MDNode>(SrcOp->getOperand(2)); 1087 unsigned NumOps = DstValue->getNumOperands() + SrcValue->getNumOperands(); 1088 Value **VP, **Values = VP = new Value*[NumOps]; 1089 for (unsigned i = 0, e = DstValue->getNumOperands(); i != e; ++i, ++VP) 1090 *VP = DstValue->getOperand(i); 1091 for (unsigned i = 0, e = SrcValue->getNumOperands(); i != e; ++i, ++VP) 1092 *VP = SrcValue->getOperand(i); 1093 DstOp->replaceOperandWith(2, MDNode::get(DstM->getContext(), 1094 ArrayRef<Value*>(Values, 1095 NumOps))); 1096 delete[] Values; 1097 break; 1098 } 1099 case Module::AppendUnique: { 1100 SmallSetVector<Value*, 16> Elts; 1101 MDNode *DstValue = cast<MDNode>(DstOp->getOperand(2)); 1102 MDNode *SrcValue = cast<MDNode>(SrcOp->getOperand(2)); 1103 for (unsigned i = 0, e = DstValue->getNumOperands(); i != e; ++i) 1104 Elts.insert(DstValue->getOperand(i)); 1105 for (unsigned i = 0, e = SrcValue->getNumOperands(); i != e; ++i) 1106 Elts.insert(SrcValue->getOperand(i)); 1107 DstOp->replaceOperandWith(2, MDNode::get(DstM->getContext(), 1108 ArrayRef<Value*>(Elts.begin(), 1109 Elts.end()))); 1110 break; 1111 } 1112 } 1113 } 1114 1115 // Check all of the requirements. 1116 for (unsigned I = 0, E = Requirements.size(); I != E; ++I) { 1117 MDNode *Requirement = Requirements[I]; 1118 MDString *Flag = cast<MDString>(Requirement->getOperand(0)); 1119 Value *ReqValue = Requirement->getOperand(1); 1120 1121 MDNode *Op = Flags[Flag]; 1122 if (!Op || Op->getOperand(2) != ReqValue) { 1123 HasErr |= emitError("linking module flags '" + Flag->getString() + 1124 "': does not have the required value"); 1125 continue; 1126 } 1127 } 1128 1129 return HasErr; 1130} 1131 1132bool ModuleLinker::run() { 1133 assert(DstM && "Null destination module"); 1134 assert(SrcM && "Null source module"); 1135 1136 // Inherit the target data from the source module if the destination module 1137 // doesn't have one already. 1138 if (DstM->getDataLayout().empty() && !SrcM->getDataLayout().empty()) 1139 DstM->setDataLayout(SrcM->getDataLayout()); 1140 1141 // Copy the target triple from the source to dest if the dest's is empty. 1142 if (DstM->getTargetTriple().empty() && !SrcM->getTargetTriple().empty()) 1143 DstM->setTargetTriple(SrcM->getTargetTriple()); 1144 1145 if (!SrcM->getDataLayout().empty() && !DstM->getDataLayout().empty() && 1146 SrcM->getDataLayout() != DstM->getDataLayout()) 1147 errs() << "WARNING: Linking two modules of different data layouts!\n"; 1148 if (!SrcM->getTargetTriple().empty() && 1149 DstM->getTargetTriple() != SrcM->getTargetTriple()) { 1150 errs() << "WARNING: Linking two modules of different target triples: "; 1151 if (!SrcM->getModuleIdentifier().empty()) 1152 errs() << SrcM->getModuleIdentifier() << ": "; 1153 errs() << "'" << SrcM->getTargetTriple() << "' and '" 1154 << DstM->getTargetTriple() << "'\n"; 1155 } 1156 1157 // Append the module inline asm string. 1158 if (!SrcM->getModuleInlineAsm().empty()) { 1159 if (DstM->getModuleInlineAsm().empty()) 1160 DstM->setModuleInlineAsm(SrcM->getModuleInlineAsm()); 1161 else 1162 DstM->setModuleInlineAsm(DstM->getModuleInlineAsm()+"\n"+ 1163 SrcM->getModuleInlineAsm()); 1164 } 1165 1166 // Loop over all of the linked values to compute type mappings. 1167 computeTypeMapping(); 1168 1169 // Insert all of the globals in src into the DstM module... without linking 1170 // initializers (which could refer to functions not yet mapped over). 1171 for (Module::global_iterator I = SrcM->global_begin(), 1172 E = SrcM->global_end(); I != E; ++I) 1173 if (linkGlobalProto(I)) 1174 return true; 1175 1176 // Link the functions together between the two modules, without doing function 1177 // bodies... this just adds external function prototypes to the DstM 1178 // function... We do this so that when we begin processing function bodies, 1179 // all of the global values that may be referenced are available in our 1180 // ValueMap. 1181 for (Module::iterator I = SrcM->begin(), E = SrcM->end(); I != E; ++I) 1182 if (linkFunctionProto(I)) 1183 return true; 1184 1185 // If there were any aliases, link them now. 1186 for (Module::alias_iterator I = SrcM->alias_begin(), 1187 E = SrcM->alias_end(); I != E; ++I) 1188 if (linkAliasProto(I)) 1189 return true; 1190 1191 for (unsigned i = 0, e = AppendingVars.size(); i != e; ++i) 1192 linkAppendingVarInit(AppendingVars[i]); 1193 1194 // Update the initializers in the DstM module now that all globals that may 1195 // be referenced are in DstM. 1196 linkGlobalInits(); 1197 1198 // Link in the function bodies that are defined in the source module into 1199 // DstM. 1200 for (Module::iterator SF = SrcM->begin(), E = SrcM->end(); SF != E; ++SF) { 1201 // Skip if not linking from source. 1202 if (DoNotLinkFromSource.count(SF)) continue; 1203 1204 // Skip if no body (function is external) or materialize. 1205 if (SF->isDeclaration()) { 1206 if (!SF->isMaterializable()) 1207 continue; 1208 if (SF->Materialize(&ErrorMsg)) 1209 return true; 1210 } 1211 1212 linkFunctionBody(cast<Function>(ValueMap[SF]), SF); 1213 SF->Dematerialize(); 1214 } 1215 1216 // Resolve all uses of aliases with aliasees. 1217 linkAliasBodies(); 1218 1219 // Remap all of the named MDNodes in Src into the DstM module. We do this 1220 // after linking GlobalValues so that MDNodes that reference GlobalValues 1221 // are properly remapped. 1222 linkNamedMDNodes(); 1223 1224 // Merge the module flags into the DstM module. 1225 if (linkModuleFlagsMetadata()) 1226 return true; 1227 1228 // Process vector of lazily linked in functions. 1229 bool LinkedInAnyFunctions; 1230 do { 1231 LinkedInAnyFunctions = false; 1232 1233 for(std::vector<Function*>::iterator I = LazilyLinkFunctions.begin(), 1234 E = LazilyLinkFunctions.end(); I != E; ++I) { 1235 if (!*I) 1236 continue; 1237 1238 Function *SF = *I; 1239 Function *DF = cast<Function>(ValueMap[SF]); 1240 1241 if (!DF->use_empty()) { 1242 1243 // Materialize if necessary. 1244 if (SF->isDeclaration()) { 1245 if (!SF->isMaterializable()) 1246 continue; 1247 if (SF->Materialize(&ErrorMsg)) 1248 return true; 1249 } 1250 1251 // Link in function body. 1252 linkFunctionBody(DF, SF); 1253 SF->Dematerialize(); 1254 1255 // "Remove" from vector by setting the element to 0. 1256 *I = 0; 1257 1258 // Set flag to indicate we may have more functions to lazily link in 1259 // since we linked in a function. 1260 LinkedInAnyFunctions = true; 1261 } 1262 } 1263 } while (LinkedInAnyFunctions); 1264 1265 // Remove any prototypes of functions that were not actually linked in. 1266 for(std::vector<Function*>::iterator I = LazilyLinkFunctions.begin(), 1267 E = LazilyLinkFunctions.end(); I != E; ++I) { 1268 if (!*I) 1269 continue; 1270 1271 Function *SF = *I; 1272 Function *DF = cast<Function>(ValueMap[SF]); 1273 if (DF->use_empty()) 1274 DF->eraseFromParent(); 1275 } 1276 1277 // Now that all of the types from the source are used, resolve any structs 1278 // copied over to the dest that didn't exist there. 1279 TypeMap.linkDefinedTypeBodies(); 1280 1281 return false; 1282} 1283 1284Linker::Linker(Module *M) : Composite(M) {} 1285 1286Linker::~Linker() { 1287} 1288 1289bool Linker::linkInModule(Module *Src, unsigned Mode, std::string *ErrorMsg) { 1290 ModuleLinker TheLinker(Composite, Src, Mode); 1291 if (TheLinker.run()) { 1292 if (ErrorMsg) 1293 *ErrorMsg = TheLinker.ErrorMsg; 1294 return true; 1295 } 1296 return false; 1297} 1298 1299//===----------------------------------------------------------------------===// 1300// LinkModules entrypoint. 1301//===----------------------------------------------------------------------===// 1302 1303/// LinkModules - This function links two modules together, with the resulting 1304/// Dest module modified to be the composite of the two input modules. If an 1305/// error occurs, true is returned and ErrorMsg (if not null) is set to indicate 1306/// the problem. Upon failure, the Dest module could be in a modified state, 1307/// and shouldn't be relied on to be consistent. 1308bool Linker::LinkModules(Module *Dest, Module *Src, unsigned Mode, 1309 std::string *ErrorMsg) { 1310 Linker L(Dest); 1311 return L.linkInModule(Src, Mode, ErrorMsg); 1312} 1313 1314//===----------------------------------------------------------------------===// 1315// C API. 1316//===----------------------------------------------------------------------===// 1317 1318LLVMBool LLVMLinkModules(LLVMModuleRef Dest, LLVMModuleRef Src, 1319 LLVMLinkerMode Mode, char **OutMessages) { 1320 std::string Messages; 1321 LLVMBool Result = Linker::LinkModules(unwrap(Dest), unwrap(Src), 1322 Mode, OutMessages? &Messages : 0); 1323 if (OutMessages) 1324 *OutMessages = strdup(Messages.c_str()); 1325 return Result; 1326} 1327