LinkModules.cpp revision e3572baab5f601c194de60077cec5e022a926b2e
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// Specifically, this: 13// * Merges global variables between the two modules 14// * Uninit + Uninit = Init, Init + Uninit = Init, Init + Init = Error if != 15// * Merges functions between two modules 16// 17//===----------------------------------------------------------------------===// 18 19#include "llvm/Linker.h" 20#include "llvm/Constants.h" 21#include "llvm/DerivedTypes.h" 22#include "llvm/LLVMContext.h" 23#include "llvm/Module.h" 24#include "llvm/TypeSymbolTable.h" 25#include "llvm/ValueSymbolTable.h" 26#include "llvm/Instructions.h" 27#include "llvm/Assembly/Writer.h" 28#include "llvm/Support/Streams.h" 29#include "llvm/Support/ErrorHandling.h" 30#include "llvm/System/Path.h" 31#include "llvm/ADT/DenseMap.h" 32#include <sstream> 33using namespace llvm; 34 35// Error - Simple wrapper function to conditionally assign to E and return true. 36// This just makes error return conditions a little bit simpler... 37static inline bool Error(std::string *E, const Twine &Message) { 38 if (E) *E = Message.str(); 39 return true; 40} 41 42// Function: ResolveTypes() 43// 44// Description: 45// Attempt to link the two specified types together. 46// 47// Inputs: 48// DestTy - The type to which we wish to resolve. 49// SrcTy - The original type which we want to resolve. 50// 51// Outputs: 52// DestST - The symbol table in which the new type should be placed. 53// 54// Return value: 55// true - There is an error and the types cannot yet be linked. 56// false - No errors. 57// 58static bool ResolveTypes(const Type *DestTy, const Type *SrcTy) { 59 if (DestTy == SrcTy) return false; // If already equal, noop 60 assert(DestTy && SrcTy && "Can't handle null types"); 61 62 if (const OpaqueType *OT = dyn_cast<OpaqueType>(DestTy)) { 63 // Type _is_ in module, just opaque... 64 const_cast<OpaqueType*>(OT)->refineAbstractTypeTo(SrcTy); 65 } else if (const OpaqueType *OT = dyn_cast<OpaqueType>(SrcTy)) { 66 const_cast<OpaqueType*>(OT)->refineAbstractTypeTo(DestTy); 67 } else { 68 return true; // Cannot link types... not-equal and neither is opaque. 69 } 70 return false; 71} 72 73/// LinkerTypeMap - This implements a map of types that is stable 74/// even if types are resolved/refined to other types. This is not a general 75/// purpose map, it is specific to the linker's use. 76namespace { 77class LinkerTypeMap : public AbstractTypeUser { 78 typedef DenseMap<const Type*, PATypeHolder> TheMapTy; 79 TheMapTy TheMap; 80 81 LinkerTypeMap(const LinkerTypeMap&); // DO NOT IMPLEMENT 82 void operator=(const LinkerTypeMap&); // DO NOT IMPLEMENT 83public: 84 LinkerTypeMap() {} 85 ~LinkerTypeMap() { 86 for (DenseMap<const Type*, PATypeHolder>::iterator I = TheMap.begin(), 87 E = TheMap.end(); I != E; ++I) 88 I->first->removeAbstractTypeUser(this); 89 } 90 91 /// lookup - Return the value for the specified type or null if it doesn't 92 /// exist. 93 const Type *lookup(const Type *Ty) const { 94 TheMapTy::const_iterator I = TheMap.find(Ty); 95 if (I != TheMap.end()) return I->second; 96 return 0; 97 } 98 99 /// erase - Remove the specified type, returning true if it was in the set. 100 bool erase(const Type *Ty) { 101 if (!TheMap.erase(Ty)) 102 return false; 103 if (Ty->isAbstract()) 104 Ty->removeAbstractTypeUser(this); 105 return true; 106 } 107 108 /// insert - This returns true if the pointer was new to the set, false if it 109 /// was already in the set. 110 bool insert(const Type *Src, const Type *Dst) { 111 if (!TheMap.insert(std::make_pair(Src, PATypeHolder(Dst))).second) 112 return false; // Already in map. 113 if (Src->isAbstract()) 114 Src->addAbstractTypeUser(this); 115 return true; 116 } 117 118protected: 119 /// refineAbstractType - The callback method invoked when an abstract type is 120 /// resolved to another type. An object must override this method to update 121 /// its internal state to reference NewType instead of OldType. 122 /// 123 virtual void refineAbstractType(const DerivedType *OldTy, 124 const Type *NewTy) { 125 TheMapTy::iterator I = TheMap.find(OldTy); 126 const Type *DstTy = I->second; 127 128 TheMap.erase(I); 129 if (OldTy->isAbstract()) 130 OldTy->removeAbstractTypeUser(this); 131 132 // Don't reinsert into the map if the key is concrete now. 133 if (NewTy->isAbstract()) 134 insert(NewTy, DstTy); 135 } 136 137 /// The other case which AbstractTypeUsers must be aware of is when a type 138 /// makes the transition from being abstract (where it has clients on it's 139 /// AbstractTypeUsers list) to concrete (where it does not). This method 140 /// notifies ATU's when this occurs for a type. 141 virtual void typeBecameConcrete(const DerivedType *AbsTy) { 142 TheMap.erase(AbsTy); 143 AbsTy->removeAbstractTypeUser(this); 144 } 145 146 // for debugging... 147 virtual void dump() const { 148 cerr << "AbstractTypeSet!\n"; 149 } 150}; 151} 152 153 154// RecursiveResolveTypes - This is just like ResolveTypes, except that it 155// recurses down into derived types, merging the used types if the parent types 156// are compatible. 157static bool RecursiveResolveTypesI(const Type *DstTy, const Type *SrcTy, 158 LinkerTypeMap &Pointers) { 159 if (DstTy == SrcTy) return false; // If already equal, noop 160 161 // If we found our opaque type, resolve it now! 162 if (isa<OpaqueType>(DstTy) || isa<OpaqueType>(SrcTy)) 163 return ResolveTypes(DstTy, SrcTy); 164 165 // Two types cannot be resolved together if they are of different primitive 166 // type. For example, we cannot resolve an int to a float. 167 if (DstTy->getTypeID() != SrcTy->getTypeID()) return true; 168 169 // If neither type is abstract, then they really are just different types. 170 if (!DstTy->isAbstract() && !SrcTy->isAbstract()) 171 return true; 172 173 // Otherwise, resolve the used type used by this derived type... 174 switch (DstTy->getTypeID()) { 175 default: 176 return true; 177 case Type::FunctionTyID: { 178 const FunctionType *DstFT = cast<FunctionType>(DstTy); 179 const FunctionType *SrcFT = cast<FunctionType>(SrcTy); 180 if (DstFT->isVarArg() != SrcFT->isVarArg() || 181 DstFT->getNumContainedTypes() != SrcFT->getNumContainedTypes()) 182 return true; 183 184 // Use TypeHolder's so recursive resolution won't break us. 185 PATypeHolder ST(SrcFT), DT(DstFT); 186 for (unsigned i = 0, e = DstFT->getNumContainedTypes(); i != e; ++i) { 187 const Type *SE = ST->getContainedType(i), *DE = DT->getContainedType(i); 188 if (SE != DE && RecursiveResolveTypesI(DE, SE, Pointers)) 189 return true; 190 } 191 return false; 192 } 193 case Type::StructTyID: { 194 const StructType *DstST = cast<StructType>(DstTy); 195 const StructType *SrcST = cast<StructType>(SrcTy); 196 if (DstST->getNumContainedTypes() != SrcST->getNumContainedTypes()) 197 return true; 198 199 PATypeHolder ST(SrcST), DT(DstST); 200 for (unsigned i = 0, e = DstST->getNumContainedTypes(); i != e; ++i) { 201 const Type *SE = ST->getContainedType(i), *DE = DT->getContainedType(i); 202 if (SE != DE && RecursiveResolveTypesI(DE, SE, Pointers)) 203 return true; 204 } 205 return false; 206 } 207 case Type::ArrayTyID: { 208 const ArrayType *DAT = cast<ArrayType>(DstTy); 209 const ArrayType *SAT = cast<ArrayType>(SrcTy); 210 if (DAT->getNumElements() != SAT->getNumElements()) return true; 211 return RecursiveResolveTypesI(DAT->getElementType(), SAT->getElementType(), 212 Pointers); 213 } 214 case Type::VectorTyID: { 215 const VectorType *DVT = cast<VectorType>(DstTy); 216 const VectorType *SVT = cast<VectorType>(SrcTy); 217 if (DVT->getNumElements() != SVT->getNumElements()) return true; 218 return RecursiveResolveTypesI(DVT->getElementType(), SVT->getElementType(), 219 Pointers); 220 } 221 case Type::PointerTyID: { 222 const PointerType *DstPT = cast<PointerType>(DstTy); 223 const PointerType *SrcPT = cast<PointerType>(SrcTy); 224 225 if (DstPT->getAddressSpace() != SrcPT->getAddressSpace()) 226 return true; 227 228 // If this is a pointer type, check to see if we have already seen it. If 229 // so, we are in a recursive branch. Cut off the search now. We cannot use 230 // an associative container for this search, because the type pointers (keys 231 // in the container) change whenever types get resolved. 232 if (SrcPT->isAbstract()) 233 if (const Type *ExistingDestTy = Pointers.lookup(SrcPT)) 234 return ExistingDestTy != DstPT; 235 236 if (DstPT->isAbstract()) 237 if (const Type *ExistingSrcTy = Pointers.lookup(DstPT)) 238 return ExistingSrcTy != SrcPT; 239 // Otherwise, add the current pointers to the vector to stop recursion on 240 // this pair. 241 if (DstPT->isAbstract()) 242 Pointers.insert(DstPT, SrcPT); 243 if (SrcPT->isAbstract()) 244 Pointers.insert(SrcPT, DstPT); 245 246 return RecursiveResolveTypesI(DstPT->getElementType(), 247 SrcPT->getElementType(), Pointers); 248 } 249 } 250} 251 252static bool RecursiveResolveTypes(const Type *DestTy, const Type *SrcTy) { 253 LinkerTypeMap PointerTypes; 254 return RecursiveResolveTypesI(DestTy, SrcTy, PointerTypes); 255} 256 257 258// LinkTypes - Go through the symbol table of the Src module and see if any 259// types are named in the src module that are not named in the Dst module. 260// Make sure there are no type name conflicts. 261static bool LinkTypes(Module *Dest, const Module *Src, std::string *Err) { 262 TypeSymbolTable *DestST = &Dest->getTypeSymbolTable(); 263 const TypeSymbolTable *SrcST = &Src->getTypeSymbolTable(); 264 265 // Look for a type plane for Type's... 266 TypeSymbolTable::const_iterator TI = SrcST->begin(); 267 TypeSymbolTable::const_iterator TE = SrcST->end(); 268 if (TI == TE) return false; // No named types, do nothing. 269 270 // Some types cannot be resolved immediately because they depend on other 271 // types being resolved to each other first. This contains a list of types we 272 // are waiting to recheck. 273 std::vector<std::string> DelayedTypesToResolve; 274 275 for ( ; TI != TE; ++TI ) { 276 const std::string &Name = TI->first; 277 const Type *RHS = TI->second; 278 279 // Check to see if this type name is already in the dest module. 280 Type *Entry = DestST->lookup(Name); 281 282 // If the name is just in the source module, bring it over to the dest. 283 if (Entry == 0) { 284 if (!Name.empty()) 285 DestST->insert(Name, const_cast<Type*>(RHS)); 286 } else if (ResolveTypes(Entry, RHS)) { 287 // They look different, save the types 'till later to resolve. 288 DelayedTypesToResolve.push_back(Name); 289 } 290 } 291 292 // Iteratively resolve types while we can... 293 while (!DelayedTypesToResolve.empty()) { 294 // Loop over all of the types, attempting to resolve them if possible... 295 unsigned OldSize = DelayedTypesToResolve.size(); 296 297 // Try direct resolution by name... 298 for (unsigned i = 0; i != DelayedTypesToResolve.size(); ++i) { 299 const std::string &Name = DelayedTypesToResolve[i]; 300 Type *T1 = SrcST->lookup(Name); 301 Type *T2 = DestST->lookup(Name); 302 if (!ResolveTypes(T2, T1)) { 303 // We are making progress! 304 DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i); 305 --i; 306 } 307 } 308 309 // Did we not eliminate any types? 310 if (DelayedTypesToResolve.size() == OldSize) { 311 // Attempt to resolve subelements of types. This allows us to merge these 312 // two types: { int* } and { opaque* } 313 for (unsigned i = 0, e = DelayedTypesToResolve.size(); i != e; ++i) { 314 const std::string &Name = DelayedTypesToResolve[i]; 315 if (!RecursiveResolveTypes(SrcST->lookup(Name), DestST->lookup(Name))) { 316 // We are making progress! 317 DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i); 318 319 // Go back to the main loop, perhaps we can resolve directly by name 320 // now... 321 break; 322 } 323 } 324 325 // If we STILL cannot resolve the types, then there is something wrong. 326 if (DelayedTypesToResolve.size() == OldSize) { 327 // Remove the symbol name from the destination. 328 DelayedTypesToResolve.pop_back(); 329 } 330 } 331 } 332 333 334 return false; 335} 336 337#ifndef NDEBUG 338static void PrintMap(const std::map<const Value*, Value*> &M) { 339 for (std::map<const Value*, Value*>::const_iterator I = M.begin(), E =M.end(); 340 I != E; ++I) { 341 cerr << " Fr: " << (void*)I->first << " "; 342 I->first->dump(); 343 cerr << " To: " << (void*)I->second << " "; 344 I->second->dump(); 345 cerr << "\n"; 346 } 347} 348#endif 349 350 351// RemapOperand - Use ValueMap to convert constants from one module to another. 352static Value *RemapOperand(const Value *In, 353 std::map<const Value*, Value*> &ValueMap, 354 LLVMContext &Context) { 355 std::map<const Value*,Value*>::const_iterator I = ValueMap.find(In); 356 if (I != ValueMap.end()) 357 return I->second; 358 359 // Check to see if it's a constant that we are interested in transforming. 360 Value *Result = 0; 361 if (const Constant *CPV = dyn_cast<Constant>(In)) { 362 if ((!isa<DerivedType>(CPV->getType()) && !isa<ConstantExpr>(CPV)) || 363 isa<ConstantInt>(CPV) || isa<ConstantAggregateZero>(CPV)) 364 return const_cast<Constant*>(CPV); // Simple constants stay identical. 365 366 if (const ConstantArray *CPA = dyn_cast<ConstantArray>(CPV)) { 367 std::vector<Constant*> Operands(CPA->getNumOperands()); 368 for (unsigned i = 0, e = CPA->getNumOperands(); i != e; ++i) 369 Operands[i] =cast<Constant>(RemapOperand(CPA->getOperand(i), ValueMap, 370 Context)); 371 Result = 372 Context.getConstantArray(cast<ArrayType>(CPA->getType()), Operands); 373 } else if (const ConstantStruct *CPS = dyn_cast<ConstantStruct>(CPV)) { 374 std::vector<Constant*> Operands(CPS->getNumOperands()); 375 for (unsigned i = 0, e = CPS->getNumOperands(); i != e; ++i) 376 Operands[i] =cast<Constant>(RemapOperand(CPS->getOperand(i), ValueMap, 377 Context)); 378 Result = 379 Context.getConstantStruct(cast<StructType>(CPS->getType()), Operands); 380 } else if (isa<ConstantPointerNull>(CPV) || isa<UndefValue>(CPV)) { 381 Result = const_cast<Constant*>(CPV); 382 } else if (const ConstantVector *CP = dyn_cast<ConstantVector>(CPV)) { 383 std::vector<Constant*> Operands(CP->getNumOperands()); 384 for (unsigned i = 0, e = CP->getNumOperands(); i != e; ++i) 385 Operands[i] = cast<Constant>(RemapOperand(CP->getOperand(i), ValueMap, 386 Context)); 387 Result = Context.getConstantVector(Operands); 388 } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CPV)) { 389 std::vector<Constant*> Ops; 390 for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) 391 Ops.push_back(cast<Constant>(RemapOperand(CE->getOperand(i),ValueMap, 392 Context))); 393 Result = CE->getWithOperands(Ops); 394 } else { 395 assert(!isa<GlobalValue>(CPV) && "Unmapped global?"); 396 llvm_unreachable("Unknown type of derived type constant value!"); 397 } 398 } else if (isa<InlineAsm>(In)) { 399 Result = const_cast<Value*>(In); 400 } 401 402 // Cache the mapping in our local map structure 403 if (Result) { 404 ValueMap[In] = Result; 405 return Result; 406 } 407 408#ifndef NDEBUG 409 cerr << "LinkModules ValueMap: \n"; 410 PrintMap(ValueMap); 411 412 cerr << "Couldn't remap value: " << (void*)In << " " << *In << "\n"; 413 llvm_unreachable("Couldn't remap value!"); 414#endif 415 return 0; 416} 417 418/// ForceRenaming - The LLVM SymbolTable class autorenames globals that conflict 419/// in the symbol table. This is good for all clients except for us. Go 420/// through the trouble to force this back. 421static void ForceRenaming(GlobalValue *GV, const std::string &Name) { 422 assert(GV->getName() != Name && "Can't force rename to self"); 423 ValueSymbolTable &ST = GV->getParent()->getValueSymbolTable(); 424 425 // If there is a conflict, rename the conflict. 426 if (GlobalValue *ConflictGV = cast_or_null<GlobalValue>(ST.lookup(Name))) { 427 assert(ConflictGV->hasLocalLinkage() && 428 "Not conflicting with a static global, should link instead!"); 429 GV->takeName(ConflictGV); 430 ConflictGV->setName(Name); // This will cause ConflictGV to get renamed 431 assert(ConflictGV->getName() != Name && "ForceRenaming didn't work"); 432 } else { 433 GV->setName(Name); // Force the name back 434 } 435} 436 437/// CopyGVAttributes - copy additional attributes (those not needed to construct 438/// a GlobalValue) from the SrcGV to the DestGV. 439static void CopyGVAttributes(GlobalValue *DestGV, const GlobalValue *SrcGV) { 440 // Use the maximum alignment, rather than just copying the alignment of SrcGV. 441 unsigned Alignment = std::max(DestGV->getAlignment(), SrcGV->getAlignment()); 442 DestGV->copyAttributesFrom(SrcGV); 443 DestGV->setAlignment(Alignment); 444} 445 446/// GetLinkageResult - This analyzes the two global values and determines what 447/// the result will look like in the destination module. In particular, it 448/// computes the resultant linkage type, computes whether the global in the 449/// source should be copied over to the destination (replacing the existing 450/// one), and computes whether this linkage is an error or not. It also performs 451/// visibility checks: we cannot link together two symbols with different 452/// visibilities. 453static bool GetLinkageResult(GlobalValue *Dest, const GlobalValue *Src, 454 GlobalValue::LinkageTypes <, bool &LinkFromSrc, 455 std::string *Err) { 456 assert((!Dest || !Src->hasLocalLinkage()) && 457 "If Src has internal linkage, Dest shouldn't be set!"); 458 if (!Dest) { 459 // Linking something to nothing. 460 LinkFromSrc = true; 461 LT = Src->getLinkage(); 462 } else if (Src->isDeclaration()) { 463 // If Src is external or if both Src & Dest are external.. Just link the 464 // external globals, we aren't adding anything. 465 if (Src->hasDLLImportLinkage()) { 466 // If one of GVs has DLLImport linkage, result should be dllimport'ed. 467 if (Dest->isDeclaration()) { 468 LinkFromSrc = true; 469 LT = Src->getLinkage(); 470 } 471 } else if (Dest->hasExternalWeakLinkage()) { 472 // If the Dest is weak, use the source linkage. 473 LinkFromSrc = true; 474 LT = Src->getLinkage(); 475 } else { 476 LinkFromSrc = false; 477 LT = Dest->getLinkage(); 478 } 479 } else if (Dest->isDeclaration() && !Dest->hasDLLImportLinkage()) { 480 // If Dest is external but Src is not: 481 LinkFromSrc = true; 482 LT = Src->getLinkage(); 483 } else if (Src->hasAppendingLinkage() || Dest->hasAppendingLinkage()) { 484 if (Src->getLinkage() != Dest->getLinkage()) 485 return Error(Err, "Linking globals named '" + Src->getName() + 486 "': can only link appending global with another appending global!"); 487 LinkFromSrc = true; // Special cased. 488 LT = Src->getLinkage(); 489 } else if (Src->isWeakForLinker()) { 490 // At this point we know that Dest has LinkOnce, External*, Weak, Common, 491 // or DLL* linkage. 492 if (Dest->hasExternalWeakLinkage() || 493 Dest->hasAvailableExternallyLinkage() || 494 (Dest->hasLinkOnceLinkage() && 495 (Src->hasWeakLinkage() || Src->hasCommonLinkage()))) { 496 LinkFromSrc = true; 497 LT = Src->getLinkage(); 498 } else { 499 LinkFromSrc = false; 500 LT = Dest->getLinkage(); 501 } 502 } else if (Dest->isWeakForLinker()) { 503 // At this point we know that Src has External* or DLL* linkage. 504 if (Src->hasExternalWeakLinkage()) { 505 LinkFromSrc = false; 506 LT = Dest->getLinkage(); 507 } else { 508 LinkFromSrc = true; 509 LT = GlobalValue::ExternalLinkage; 510 } 511 } else { 512 assert((Dest->hasExternalLinkage() || 513 Dest->hasDLLImportLinkage() || 514 Dest->hasDLLExportLinkage() || 515 Dest->hasExternalWeakLinkage()) && 516 (Src->hasExternalLinkage() || 517 Src->hasDLLImportLinkage() || 518 Src->hasDLLExportLinkage() || 519 Src->hasExternalWeakLinkage()) && 520 "Unexpected linkage type!"); 521 return Error(Err, "Linking globals named '" + Src->getName() + 522 "': symbol multiply defined!"); 523 } 524 525 // Check visibility 526 if (Dest && Src->getVisibility() != Dest->getVisibility()) 527 if (!Src->isDeclaration() && !Dest->isDeclaration()) 528 return Error(Err, "Linking globals named '" + Src->getName() + 529 "': symbols have different visibilities!"); 530 return false; 531} 532 533// LinkGlobals - Loop through the global variables in the src module and merge 534// them into the dest module. 535static bool LinkGlobals(Module *Dest, const Module *Src, 536 std::map<const Value*, Value*> &ValueMap, 537 std::multimap<std::string, GlobalVariable *> &AppendingVars, 538 std::string *Err) { 539 ValueSymbolTable &DestSymTab = Dest->getValueSymbolTable(); 540 LLVMContext &Context = Dest->getContext(); 541 542 // Loop over all of the globals in the src module, mapping them over as we go 543 for (Module::const_global_iterator I = Src->global_begin(), 544 E = Src->global_end(); I != E; ++I) { 545 const GlobalVariable *SGV = I; 546 GlobalValue *DGV = 0; 547 548 // Check to see if may have to link the global with the global, alias or 549 // function. 550 if (SGV->hasName() && !SGV->hasLocalLinkage()) 551 DGV = cast_or_null<GlobalValue>(DestSymTab.lookup(SGV->getNameRef())); 552 553 // If we found a global with the same name in the dest module, but it has 554 // internal linkage, we are really not doing any linkage here. 555 if (DGV && DGV->hasLocalLinkage()) 556 DGV = 0; 557 558 // If types don't agree due to opaque types, try to resolve them. 559 if (DGV && DGV->getType() != SGV->getType()) 560 RecursiveResolveTypes(SGV->getType(), DGV->getType()); 561 562 assert((SGV->hasInitializer() || SGV->hasExternalWeakLinkage() || 563 SGV->hasExternalLinkage() || SGV->hasDLLImportLinkage()) && 564 "Global must either be external or have an initializer!"); 565 566 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; 567 bool LinkFromSrc = false; 568 if (GetLinkageResult(DGV, SGV, NewLinkage, LinkFromSrc, Err)) 569 return true; 570 571 if (DGV == 0) { 572 // No linking to be performed, simply create an identical version of the 573 // symbol over in the dest module... the initializer will be filled in 574 // later by LinkGlobalInits. 575 GlobalVariable *NewDGV = 576 new GlobalVariable(*Dest, SGV->getType()->getElementType(), 577 SGV->isConstant(), SGV->getLinkage(), /*init*/0, 578 SGV->getName(), 0, false, 579 SGV->getType()->getAddressSpace()); 580 // Propagate alignment, visibility and section info. 581 CopyGVAttributes(NewDGV, SGV); 582 583 // If the LLVM runtime renamed the global, but it is an externally visible 584 // symbol, DGV must be an existing global with internal linkage. Rename 585 // it. 586 if (!NewDGV->hasLocalLinkage() && NewDGV->getName() != SGV->getName()) 587 ForceRenaming(NewDGV, SGV->getName()); 588 589 // Make sure to remember this mapping. 590 ValueMap[SGV] = NewDGV; 591 592 // Keep track that this is an appending variable. 593 if (SGV->hasAppendingLinkage()) 594 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV)); 595 continue; 596 } 597 598 // If the visibilities of the symbols disagree and the destination is a 599 // prototype, take the visibility of its input. 600 if (DGV->isDeclaration()) 601 DGV->setVisibility(SGV->getVisibility()); 602 603 if (DGV->hasAppendingLinkage()) { 604 // No linking is performed yet. Just insert a new copy of the global, and 605 // keep track of the fact that it is an appending variable in the 606 // AppendingVars map. The name is cleared out so that no linkage is 607 // performed. 608 GlobalVariable *NewDGV = 609 new GlobalVariable(*Dest, SGV->getType()->getElementType(), 610 SGV->isConstant(), SGV->getLinkage(), /*init*/0, 611 "", 0, false, 612 SGV->getType()->getAddressSpace()); 613 614 // Set alignment allowing CopyGVAttributes merge it with alignment of SGV. 615 NewDGV->setAlignment(DGV->getAlignment()); 616 // Propagate alignment, section and visibility info. 617 CopyGVAttributes(NewDGV, SGV); 618 619 // Make sure to remember this mapping... 620 ValueMap[SGV] = NewDGV; 621 622 // Keep track that this is an appending variable... 623 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV)); 624 continue; 625 } 626 627 if (LinkFromSrc) { 628 if (isa<GlobalAlias>(DGV)) 629 return Error(Err, "Global-Alias Collision on '" + SGV->getName() + 630 "': symbol multiple defined"); 631 632 // If the types don't match, and if we are to link from the source, nuke 633 // DGV and create a new one of the appropriate type. Note that the thing 634 // we are replacing may be a function (if a prototype, weak, etc) or a 635 // global variable. 636 GlobalVariable *NewDGV = 637 new GlobalVariable(*Dest, SGV->getType()->getElementType(), 638 SGV->isConstant(), NewLinkage, /*init*/0, 639 DGV->getName(), 0, false, 640 SGV->getType()->getAddressSpace()); 641 642 // Propagate alignment, section, and visibility info. 643 CopyGVAttributes(NewDGV, SGV); 644 DGV->replaceAllUsesWith(Context.getConstantExprBitCast(NewDGV, 645 DGV->getType())); 646 647 // DGV will conflict with NewDGV because they both had the same 648 // name. We must erase this now so ForceRenaming doesn't assert 649 // because DGV might not have internal linkage. 650 if (GlobalVariable *Var = dyn_cast<GlobalVariable>(DGV)) 651 Var->eraseFromParent(); 652 else 653 cast<Function>(DGV)->eraseFromParent(); 654 DGV = NewDGV; 655 656 // If the symbol table renamed the global, but it is an externally visible 657 // symbol, DGV must be an existing global with internal linkage. Rename. 658 if (NewDGV->getName() != SGV->getName() && !NewDGV->hasLocalLinkage()) 659 ForceRenaming(NewDGV, SGV->getName()); 660 661 // Inherit const as appropriate. 662 NewDGV->setConstant(SGV->isConstant()); 663 664 // Make sure to remember this mapping. 665 ValueMap[SGV] = NewDGV; 666 continue; 667 } 668 669 // Not "link from source", keep the one in the DestModule and remap the 670 // input onto it. 671 672 // Special case for const propagation. 673 if (GlobalVariable *DGVar = dyn_cast<GlobalVariable>(DGV)) 674 if (DGVar->isDeclaration() && SGV->isConstant() && !DGVar->isConstant()) 675 DGVar->setConstant(true); 676 677 // SGV is global, but DGV is alias. 678 if (isa<GlobalAlias>(DGV)) { 679 // The only valid mappings are: 680 // - SGV is external declaration, which is effectively a no-op. 681 // - SGV is weak, when we just need to throw SGV out. 682 if (!SGV->isDeclaration() && !SGV->isWeakForLinker()) 683 return Error(Err, "Global-Alias Collision on '" + SGV->getName() + 684 "': symbol multiple defined"); 685 } 686 687 // Set calculated linkage 688 DGV->setLinkage(NewLinkage); 689 690 // Make sure to remember this mapping... 691 ValueMap[SGV] = Context.getConstantExprBitCast(DGV, SGV->getType()); 692 } 693 return false; 694} 695 696static GlobalValue::LinkageTypes 697CalculateAliasLinkage(const GlobalValue *SGV, const GlobalValue *DGV) { 698 GlobalValue::LinkageTypes SL = SGV->getLinkage(); 699 GlobalValue::LinkageTypes DL = DGV->getLinkage(); 700 if (SL == GlobalValue::ExternalLinkage || DL == GlobalValue::ExternalLinkage) 701 return GlobalValue::ExternalLinkage; 702 else if (SL == GlobalValue::WeakAnyLinkage || 703 DL == GlobalValue::WeakAnyLinkage) 704 return GlobalValue::WeakAnyLinkage; 705 else if (SL == GlobalValue::WeakODRLinkage || 706 DL == GlobalValue::WeakODRLinkage) 707 return GlobalValue::WeakODRLinkage; 708 else if (SL == GlobalValue::InternalLinkage && 709 DL == GlobalValue::InternalLinkage) 710 return GlobalValue::InternalLinkage; 711 else if (SL == GlobalValue::LinkerPrivateLinkage && 712 DL == GlobalValue::LinkerPrivateLinkage) 713 return GlobalValue::LinkerPrivateLinkage; 714 else { 715 assert (SL == GlobalValue::PrivateLinkage && 716 DL == GlobalValue::PrivateLinkage && "Unexpected linkage type"); 717 return GlobalValue::PrivateLinkage; 718 } 719} 720 721// LinkAlias - Loop through the alias in the src module and link them into the 722// dest module. We're assuming, that all functions/global variables were already 723// linked in. 724static bool LinkAlias(Module *Dest, const Module *Src, 725 std::map<const Value*, Value*> &ValueMap, 726 std::string *Err) { 727 LLVMContext &Context = Dest->getContext(); 728 729 // Loop over all alias in the src module 730 for (Module::const_alias_iterator I = Src->alias_begin(), 731 E = Src->alias_end(); I != E; ++I) { 732 const GlobalAlias *SGA = I; 733 const GlobalValue *SAliasee = SGA->getAliasedGlobal(); 734 GlobalAlias *NewGA = NULL; 735 736 // Globals were already linked, thus we can just query ValueMap for variant 737 // of SAliasee in Dest. 738 std::map<const Value*,Value*>::const_iterator VMI = ValueMap.find(SAliasee); 739 assert(VMI != ValueMap.end() && "Aliasee not linked"); 740 GlobalValue* DAliasee = cast<GlobalValue>(VMI->second); 741 GlobalValue* DGV = NULL; 742 743 // Try to find something 'similar' to SGA in destination module. 744 if (!DGV && !SGA->hasLocalLinkage()) { 745 DGV = Dest->getNamedAlias(SGA->getName()); 746 747 // If types don't agree due to opaque types, try to resolve them. 748 if (DGV && DGV->getType() != SGA->getType()) 749 RecursiveResolveTypes(SGA->getType(), DGV->getType()); 750 } 751 752 if (!DGV && !SGA->hasLocalLinkage()) { 753 DGV = Dest->getGlobalVariable(SGA->getName()); 754 755 // If types don't agree due to opaque types, try to resolve them. 756 if (DGV && DGV->getType() != SGA->getType()) 757 RecursiveResolveTypes(SGA->getType(), DGV->getType()); 758 } 759 760 if (!DGV && !SGA->hasLocalLinkage()) { 761 DGV = Dest->getFunction(SGA->getName()); 762 763 // If types don't agree due to opaque types, try to resolve them. 764 if (DGV && DGV->getType() != SGA->getType()) 765 RecursiveResolveTypes(SGA->getType(), DGV->getType()); 766 } 767 768 // No linking to be performed on internal stuff. 769 if (DGV && DGV->hasLocalLinkage()) 770 DGV = NULL; 771 772 if (GlobalAlias *DGA = dyn_cast_or_null<GlobalAlias>(DGV)) { 773 // Types are known to be the same, check whether aliasees equal. As 774 // globals are already linked we just need query ValueMap to find the 775 // mapping. 776 if (DAliasee == DGA->getAliasedGlobal()) { 777 // This is just two copies of the same alias. Propagate linkage, if 778 // necessary. 779 DGA->setLinkage(CalculateAliasLinkage(SGA, DGA)); 780 781 NewGA = DGA; 782 // Proceed to 'common' steps 783 } else 784 return Error(Err, "Alias Collision on '" + SGA->getName()+ 785 "': aliases have different aliasees"); 786 } else if (GlobalVariable *DGVar = dyn_cast_or_null<GlobalVariable>(DGV)) { 787 // The only allowed way is to link alias with external declaration or weak 788 // symbol.. 789 if (DGVar->isDeclaration() || DGVar->isWeakForLinker()) { 790 // But only if aliasee is global too... 791 if (!isa<GlobalVariable>(DAliasee)) 792 return Error(Err, "Global-Alias Collision on '" + SGA->getName() + 793 "': aliasee is not global variable"); 794 795 NewGA = new GlobalAlias(SGA->getType(), SGA->getLinkage(), 796 SGA->getName(), DAliasee, Dest); 797 CopyGVAttributes(NewGA, SGA); 798 799 // Any uses of DGV need to change to NewGA, with cast, if needed. 800 if (SGA->getType() != DGVar->getType()) 801 DGVar->replaceAllUsesWith(Context.getConstantExprBitCast(NewGA, 802 DGVar->getType())); 803 else 804 DGVar->replaceAllUsesWith(NewGA); 805 806 // DGVar will conflict with NewGA because they both had the same 807 // name. We must erase this now so ForceRenaming doesn't assert 808 // because DGV might not have internal linkage. 809 DGVar->eraseFromParent(); 810 811 // Proceed to 'common' steps 812 } else 813 return Error(Err, "Global-Alias Collision on '" + SGA->getName() + 814 "': symbol multiple defined"); 815 } else if (Function *DF = dyn_cast_or_null<Function>(DGV)) { 816 // The only allowed way is to link alias with external declaration or weak 817 // symbol... 818 if (DF->isDeclaration() || DF->isWeakForLinker()) { 819 // But only if aliasee is function too... 820 if (!isa<Function>(DAliasee)) 821 return Error(Err, "Function-Alias Collision on '" + SGA->getName() + 822 "': aliasee is not function"); 823 824 NewGA = new GlobalAlias(SGA->getType(), SGA->getLinkage(), 825 SGA->getName(), DAliasee, Dest); 826 CopyGVAttributes(NewGA, SGA); 827 828 // Any uses of DF need to change to NewGA, with cast, if needed. 829 if (SGA->getType() != DF->getType()) 830 DF->replaceAllUsesWith(Context.getConstantExprBitCast(NewGA, 831 DF->getType())); 832 else 833 DF->replaceAllUsesWith(NewGA); 834 835 // DF will conflict with NewGA because they both had the same 836 // name. We must erase this now so ForceRenaming doesn't assert 837 // because DF might not have internal linkage. 838 DF->eraseFromParent(); 839 840 // Proceed to 'common' steps 841 } else 842 return Error(Err, "Function-Alias Collision on '" + SGA->getName() + 843 "': symbol multiple defined"); 844 } else { 845 // No linking to be performed, simply create an identical version of the 846 // alias over in the dest module... 847 848 NewGA = new GlobalAlias(SGA->getType(), SGA->getLinkage(), 849 SGA->getName(), DAliasee, Dest); 850 CopyGVAttributes(NewGA, SGA); 851 852 // Proceed to 'common' steps 853 } 854 855 assert(NewGA && "No alias was created in destination module!"); 856 857 // If the symbol table renamed the alias, but it is an externally visible 858 // symbol, DGA must be an global value with internal linkage. Rename it. 859 if (NewGA->getName() != SGA->getName() && 860 !NewGA->hasLocalLinkage()) 861 ForceRenaming(NewGA, SGA->getName()); 862 863 // Remember this mapping so uses in the source module get remapped 864 // later by RemapOperand. 865 ValueMap[SGA] = NewGA; 866 } 867 868 return false; 869} 870 871 872// LinkGlobalInits - Update the initializers in the Dest module now that all 873// globals that may be referenced are in Dest. 874static bool LinkGlobalInits(Module *Dest, const Module *Src, 875 std::map<const Value*, Value*> &ValueMap, 876 std::string *Err) { 877 // Loop over all of the globals in the src module, mapping them over as we go 878 for (Module::const_global_iterator I = Src->global_begin(), 879 E = Src->global_end(); I != E; ++I) { 880 const GlobalVariable *SGV = I; 881 882 if (SGV->hasInitializer()) { // Only process initialized GV's 883 // Figure out what the initializer looks like in the dest module... 884 Constant *SInit = 885 cast<Constant>(RemapOperand(SGV->getInitializer(), ValueMap, 886 Dest->getContext())); 887 // Grab destination global variable or alias. 888 GlobalValue *DGV = cast<GlobalValue>(ValueMap[SGV]->stripPointerCasts()); 889 890 // If dest if global variable, check that initializers match. 891 if (GlobalVariable *DGVar = dyn_cast<GlobalVariable>(DGV)) { 892 if (DGVar->hasInitializer()) { 893 if (SGV->hasExternalLinkage()) { 894 if (DGVar->getInitializer() != SInit) 895 return Error(Err, "Global Variable Collision on '" + 896 SGV->getName() + 897 "': global variables have different initializers"); 898 } else if (DGVar->isWeakForLinker()) { 899 // Nothing is required, mapped values will take the new global 900 // automatically. 901 } else if (SGV->isWeakForLinker()) { 902 // Nothing is required, mapped values will take the new global 903 // automatically. 904 } else if (DGVar->hasAppendingLinkage()) { 905 llvm_unreachable("Appending linkage unimplemented!"); 906 } else { 907 llvm_unreachable("Unknown linkage!"); 908 } 909 } else { 910 // Copy the initializer over now... 911 DGVar->setInitializer(SInit); 912 } 913 } else { 914 // Destination is alias, the only valid situation is when source is 915 // weak. Also, note, that we already checked linkage in LinkGlobals(), 916 // thus we assert here. 917 // FIXME: Should we weaken this assumption, 'dereference' alias and 918 // check for initializer of aliasee? 919 assert(SGV->isWeakForLinker()); 920 } 921 } 922 } 923 return false; 924} 925 926// LinkFunctionProtos - Link the functions together between the two modules, 927// without doing function bodies... this just adds external function prototypes 928// to the Dest function... 929// 930static bool LinkFunctionProtos(Module *Dest, const Module *Src, 931 std::map<const Value*, Value*> &ValueMap, 932 std::string *Err) { 933 ValueSymbolTable &DestSymTab = Dest->getValueSymbolTable(); 934 LLVMContext &Context = Dest->getContext(); 935 936 // Loop over all of the functions in the src module, mapping them over 937 for (Module::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) { 938 const Function *SF = I; // SrcFunction 939 GlobalValue *DGV = 0; 940 941 // Check to see if may have to link the function with the global, alias or 942 // function. 943 if (SF->hasName() && !SF->hasLocalLinkage()) 944 DGV = cast_or_null<GlobalValue>(DestSymTab.lookup(SF->getNameRef())); 945 946 // If we found a global with the same name in the dest module, but it has 947 // internal linkage, we are really not doing any linkage here. 948 if (DGV && DGV->hasLocalLinkage()) 949 DGV = 0; 950 951 // If types don't agree due to opaque types, try to resolve them. 952 if (DGV && DGV->getType() != SF->getType()) 953 RecursiveResolveTypes(SF->getType(), DGV->getType()); 954 955 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; 956 bool LinkFromSrc = false; 957 if (GetLinkageResult(DGV, SF, NewLinkage, LinkFromSrc, Err)) 958 return true; 959 960 // If there is no linkage to be performed, just bring over SF without 961 // modifying it. 962 if (DGV == 0) { 963 // Function does not already exist, simply insert an function signature 964 // identical to SF into the dest module. 965 Function *NewDF = Function::Create(SF->getFunctionType(), 966 SF->getLinkage(), 967 SF->getName(), Dest); 968 CopyGVAttributes(NewDF, SF); 969 970 // If the LLVM runtime renamed the function, but it is an externally 971 // visible symbol, DF must be an existing function with internal linkage. 972 // Rename it. 973 if (!NewDF->hasLocalLinkage() && NewDF->getName() != SF->getName()) 974 ForceRenaming(NewDF, SF->getName()); 975 976 // ... and remember this mapping... 977 ValueMap[SF] = NewDF; 978 continue; 979 } 980 981 // If the visibilities of the symbols disagree and the destination is a 982 // prototype, take the visibility of its input. 983 if (DGV->isDeclaration()) 984 DGV->setVisibility(SF->getVisibility()); 985 986 if (LinkFromSrc) { 987 if (isa<GlobalAlias>(DGV)) 988 return Error(Err, "Function-Alias Collision on '" + SF->getName() + 989 "': symbol multiple defined"); 990 991 // We have a definition of the same name but different type in the 992 // source module. Copy the prototype to the destination and replace 993 // uses of the destination's prototype with the new prototype. 994 Function *NewDF = Function::Create(SF->getFunctionType(), NewLinkage, 995 SF->getName(), Dest); 996 CopyGVAttributes(NewDF, SF); 997 998 // Any uses of DF need to change to NewDF, with cast 999 DGV->replaceAllUsesWith(Context.getConstantExprBitCast(NewDF, 1000 DGV->getType())); 1001 1002 // DF will conflict with NewDF because they both had the same. We must 1003 // erase this now so ForceRenaming doesn't assert because DF might 1004 // not have internal linkage. 1005 if (GlobalVariable *Var = dyn_cast<GlobalVariable>(DGV)) 1006 Var->eraseFromParent(); 1007 else 1008 cast<Function>(DGV)->eraseFromParent(); 1009 1010 // If the symbol table renamed the function, but it is an externally 1011 // visible symbol, DF must be an existing function with internal 1012 // linkage. Rename it. 1013 if (NewDF->getName() != SF->getName() && !NewDF->hasLocalLinkage()) 1014 ForceRenaming(NewDF, SF->getName()); 1015 1016 // Remember this mapping so uses in the source module get remapped 1017 // later by RemapOperand. 1018 ValueMap[SF] = NewDF; 1019 continue; 1020 } 1021 1022 // Not "link from source", keep the one in the DestModule and remap the 1023 // input onto it. 1024 1025 if (isa<GlobalAlias>(DGV)) { 1026 // The only valid mappings are: 1027 // - SF is external declaration, which is effectively a no-op. 1028 // - SF is weak, when we just need to throw SF out. 1029 if (!SF->isDeclaration() && !SF->isWeakForLinker()) 1030 return Error(Err, "Function-Alias Collision on '" + SF->getName() + 1031 "': symbol multiple defined"); 1032 } 1033 1034 // Set calculated linkage 1035 DGV->setLinkage(NewLinkage); 1036 1037 // Make sure to remember this mapping. 1038 ValueMap[SF] = Context.getConstantExprBitCast(DGV, SF->getType()); 1039 } 1040 return false; 1041} 1042 1043// LinkFunctionBody - Copy the source function over into the dest function and 1044// fix up references to values. At this point we know that Dest is an external 1045// function, and that Src is not. 1046static bool LinkFunctionBody(Function *Dest, Function *Src, 1047 std::map<const Value*, Value*> &ValueMap, 1048 std::string *Err) { 1049 assert(Src && Dest && Dest->isDeclaration() && !Src->isDeclaration()); 1050 1051 // Go through and convert function arguments over, remembering the mapping. 1052 Function::arg_iterator DI = Dest->arg_begin(); 1053 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end(); 1054 I != E; ++I, ++DI) { 1055 DI->setName(I->getName()); // Copy the name information over... 1056 1057 // Add a mapping to our local map 1058 ValueMap[I] = DI; 1059 } 1060 1061 // Splice the body of the source function into the dest function. 1062 Dest->getBasicBlockList().splice(Dest->end(), Src->getBasicBlockList()); 1063 1064 // At this point, all of the instructions and values of the function are now 1065 // copied over. The only problem is that they are still referencing values in 1066 // the Source function as operands. Loop through all of the operands of the 1067 // functions and patch them up to point to the local versions... 1068 // 1069 for (Function::iterator BB = Dest->begin(), BE = Dest->end(); BB != BE; ++BB) 1070 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) 1071 for (Instruction::op_iterator OI = I->op_begin(), OE = I->op_end(); 1072 OI != OE; ++OI) 1073 if (!isa<Instruction>(*OI) && !isa<BasicBlock>(*OI)) 1074 *OI = RemapOperand(*OI, ValueMap, Dest->getContext()); 1075 1076 // There is no need to map the arguments anymore. 1077 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end(); 1078 I != E; ++I) 1079 ValueMap.erase(I); 1080 1081 return false; 1082} 1083 1084 1085// LinkFunctionBodies - Link in the function bodies that are defined in the 1086// source module into the DestModule. This consists basically of copying the 1087// function over and fixing up references to values. 1088static bool LinkFunctionBodies(Module *Dest, Module *Src, 1089 std::map<const Value*, Value*> &ValueMap, 1090 std::string *Err) { 1091 1092 // Loop over all of the functions in the src module, mapping them over as we 1093 // go 1094 for (Module::iterator SF = Src->begin(), E = Src->end(); SF != E; ++SF) { 1095 if (!SF->isDeclaration()) { // No body if function is external 1096 Function *DF = dyn_cast<Function>(ValueMap[SF]); // Destination function 1097 1098 // DF not external SF external? 1099 if (DF && DF->isDeclaration()) 1100 // Only provide the function body if there isn't one already. 1101 if (LinkFunctionBody(DF, SF, ValueMap, Err)) 1102 return true; 1103 } 1104 } 1105 return false; 1106} 1107 1108// LinkAppendingVars - If there were any appending global variables, link them 1109// together now. Return true on error. 1110static bool LinkAppendingVars(Module *M, 1111 std::multimap<std::string, GlobalVariable *> &AppendingVars, 1112 std::string *ErrorMsg) { 1113 if (AppendingVars.empty()) return false; // Nothing to do. 1114 1115 LLVMContext &Context = M->getContext(); 1116 1117 // Loop over the multimap of appending vars, processing any variables with the 1118 // same name, forming a new appending global variable with both of the 1119 // initializers merged together, then rewrite references to the old variables 1120 // and delete them. 1121 std::vector<Constant*> Inits; 1122 while (AppendingVars.size() > 1) { 1123 // Get the first two elements in the map... 1124 std::multimap<std::string, 1125 GlobalVariable*>::iterator Second = AppendingVars.begin(), First=Second++; 1126 1127 // If the first two elements are for different names, there is no pair... 1128 // Otherwise there is a pair, so link them together... 1129 if (First->first == Second->first) { 1130 GlobalVariable *G1 = First->second, *G2 = Second->second; 1131 const ArrayType *T1 = cast<ArrayType>(G1->getType()->getElementType()); 1132 const ArrayType *T2 = cast<ArrayType>(G2->getType()->getElementType()); 1133 1134 // Check to see that they two arrays agree on type... 1135 if (T1->getElementType() != T2->getElementType()) 1136 return Error(ErrorMsg, 1137 "Appending variables with different element types need to be linked!"); 1138 if (G1->isConstant() != G2->isConstant()) 1139 return Error(ErrorMsg, 1140 "Appending variables linked with different const'ness!"); 1141 1142 if (G1->getAlignment() != G2->getAlignment()) 1143 return Error(ErrorMsg, 1144 "Appending variables with different alignment need to be linked!"); 1145 1146 if (G1->getVisibility() != G2->getVisibility()) 1147 return Error(ErrorMsg, 1148 "Appending variables with different visibility need to be linked!"); 1149 1150 if (G1->getSection() != G2->getSection()) 1151 return Error(ErrorMsg, 1152 "Appending variables with different section name need to be linked!"); 1153 1154 unsigned NewSize = T1->getNumElements() + T2->getNumElements(); 1155 ArrayType *NewType = Context.getArrayType(T1->getElementType(), 1156 NewSize); 1157 1158 G1->setName(""); // Clear G1's name in case of a conflict! 1159 1160 // Create the new global variable... 1161 GlobalVariable *NG = 1162 new GlobalVariable(*M, NewType, G1->isConstant(), G1->getLinkage(), 1163 /*init*/0, First->first, 0, G1->isThreadLocal(), 1164 G1->getType()->getAddressSpace()); 1165 1166 // Propagate alignment, visibility and section info. 1167 CopyGVAttributes(NG, G1); 1168 1169 // Merge the initializer... 1170 Inits.reserve(NewSize); 1171 if (ConstantArray *I = dyn_cast<ConstantArray>(G1->getInitializer())) { 1172 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i) 1173 Inits.push_back(I->getOperand(i)); 1174 } else { 1175 assert(isa<ConstantAggregateZero>(G1->getInitializer())); 1176 Constant *CV = Context.getNullValue(T1->getElementType()); 1177 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i) 1178 Inits.push_back(CV); 1179 } 1180 if (ConstantArray *I = dyn_cast<ConstantArray>(G2->getInitializer())) { 1181 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i) 1182 Inits.push_back(I->getOperand(i)); 1183 } else { 1184 assert(isa<ConstantAggregateZero>(G2->getInitializer())); 1185 Constant *CV = Context.getNullValue(T2->getElementType()); 1186 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i) 1187 Inits.push_back(CV); 1188 } 1189 NG->setInitializer(Context.getConstantArray(NewType, Inits)); 1190 Inits.clear(); 1191 1192 // Replace any uses of the two global variables with uses of the new 1193 // global... 1194 1195 // FIXME: This should rewrite simple/straight-forward uses such as 1196 // getelementptr instructions to not use the Cast! 1197 G1->replaceAllUsesWith(Context.getConstantExprBitCast(NG, 1198 G1->getType())); 1199 G2->replaceAllUsesWith(Context.getConstantExprBitCast(NG, 1200 G2->getType())); 1201 1202 // Remove the two globals from the module now... 1203 M->getGlobalList().erase(G1); 1204 M->getGlobalList().erase(G2); 1205 1206 // Put the new global into the AppendingVars map so that we can handle 1207 // linking of more than two vars... 1208 Second->second = NG; 1209 } 1210 AppendingVars.erase(First); 1211 } 1212 1213 return false; 1214} 1215 1216static bool ResolveAliases(Module *Dest) { 1217 for (Module::alias_iterator I = Dest->alias_begin(), E = Dest->alias_end(); 1218 I != E; ++I) 1219 if (const GlobalValue *GV = I->resolveAliasedGlobal()) 1220 if (GV != I && !GV->isDeclaration()) 1221 I->replaceAllUsesWith(const_cast<GlobalValue*>(GV)); 1222 1223 return false; 1224} 1225 1226// LinkModules - This function links two modules together, with the resulting 1227// left module modified to be the composite of the two input modules. If an 1228// error occurs, true is returned and ErrorMsg (if not null) is set to indicate 1229// the problem. Upon failure, the Dest module could be in a modified state, and 1230// shouldn't be relied on to be consistent. 1231bool 1232Linker::LinkModules(Module *Dest, Module *Src, std::string *ErrorMsg) { 1233 assert(Dest != 0 && "Invalid Destination module"); 1234 assert(Src != 0 && "Invalid Source Module"); 1235 1236 if (Dest->getDataLayout().empty()) { 1237 if (!Src->getDataLayout().empty()) { 1238 Dest->setDataLayout(Src->getDataLayout()); 1239 } else { 1240 std::string DataLayout; 1241 1242 if (Dest->getEndianness() == Module::AnyEndianness) { 1243 if (Src->getEndianness() == Module::BigEndian) 1244 DataLayout.append("E"); 1245 else if (Src->getEndianness() == Module::LittleEndian) 1246 DataLayout.append("e"); 1247 } 1248 1249 if (Dest->getPointerSize() == Module::AnyPointerSize) { 1250 if (Src->getPointerSize() == Module::Pointer64) 1251 DataLayout.append(DataLayout.length() == 0 ? "p:64:64" : "-p:64:64"); 1252 else if (Src->getPointerSize() == Module::Pointer32) 1253 DataLayout.append(DataLayout.length() == 0 ? "p:32:32" : "-p:32:32"); 1254 } 1255 Dest->setDataLayout(DataLayout); 1256 } 1257 } 1258 1259 // Copy the target triple from the source to dest if the dest's is empty. 1260 if (Dest->getTargetTriple().empty() && !Src->getTargetTriple().empty()) 1261 Dest->setTargetTriple(Src->getTargetTriple()); 1262 1263 if (!Src->getDataLayout().empty() && !Dest->getDataLayout().empty() && 1264 Src->getDataLayout() != Dest->getDataLayout()) 1265 cerr << "WARNING: Linking two modules of different data layouts!\n"; 1266 if (!Src->getTargetTriple().empty() && 1267 Dest->getTargetTriple() != Src->getTargetTriple()) 1268 cerr << "WARNING: Linking two modules of different target triples!\n"; 1269 1270 // Append the module inline asm string. 1271 if (!Src->getModuleInlineAsm().empty()) { 1272 if (Dest->getModuleInlineAsm().empty()) 1273 Dest->setModuleInlineAsm(Src->getModuleInlineAsm()); 1274 else 1275 Dest->setModuleInlineAsm(Dest->getModuleInlineAsm()+"\n"+ 1276 Src->getModuleInlineAsm()); 1277 } 1278 1279 // Update the destination module's dependent libraries list with the libraries 1280 // from the source module. There's no opportunity for duplicates here as the 1281 // Module ensures that duplicate insertions are discarded. 1282 for (Module::lib_iterator SI = Src->lib_begin(), SE = Src->lib_end(); 1283 SI != SE; ++SI) 1284 Dest->addLibrary(*SI); 1285 1286 // LinkTypes - Go through the symbol table of the Src module and see if any 1287 // types are named in the src module that are not named in the Dst module. 1288 // Make sure there are no type name conflicts. 1289 if (LinkTypes(Dest, Src, ErrorMsg)) 1290 return true; 1291 1292 // ValueMap - Mapping of values from what they used to be in Src, to what they 1293 // are now in Dest. 1294 std::map<const Value*, Value*> ValueMap; 1295 1296 // AppendingVars - Keep track of global variables in the destination module 1297 // with appending linkage. After the module is linked together, they are 1298 // appended and the module is rewritten. 1299 std::multimap<std::string, GlobalVariable *> AppendingVars; 1300 for (Module::global_iterator I = Dest->global_begin(), E = Dest->global_end(); 1301 I != E; ++I) { 1302 // Add all of the appending globals already in the Dest module to 1303 // AppendingVars. 1304 if (I->hasAppendingLinkage()) 1305 AppendingVars.insert(std::make_pair(I->getName(), I)); 1306 } 1307 1308 // Insert all of the globals in src into the Dest module... without linking 1309 // initializers (which could refer to functions not yet mapped over). 1310 if (LinkGlobals(Dest, Src, ValueMap, AppendingVars, ErrorMsg)) 1311 return true; 1312 1313 // Link the functions together between the two modules, without doing function 1314 // bodies... this just adds external function prototypes to the Dest 1315 // function... We do this so that when we begin processing function bodies, 1316 // all of the global values that may be referenced are available in our 1317 // ValueMap. 1318 if (LinkFunctionProtos(Dest, Src, ValueMap, ErrorMsg)) 1319 return true; 1320 1321 // If there were any alias, link them now. We really need to do this now, 1322 // because all of the aliases that may be referenced need to be available in 1323 // ValueMap 1324 if (LinkAlias(Dest, Src, ValueMap, ErrorMsg)) return true; 1325 1326 // Update the initializers in the Dest module now that all globals that may 1327 // be referenced are in Dest. 1328 if (LinkGlobalInits(Dest, Src, ValueMap, ErrorMsg)) return true; 1329 1330 // Link in the function bodies that are defined in the source module into the 1331 // DestModule. This consists basically of copying the function over and 1332 // fixing up references to values. 1333 if (LinkFunctionBodies(Dest, Src, ValueMap, ErrorMsg)) return true; 1334 1335 // If there were any appending global variables, link them together now. 1336 if (LinkAppendingVars(Dest, AppendingVars, ErrorMsg)) return true; 1337 1338 // Resolve all uses of aliases with aliasees 1339 if (ResolveAliases(Dest)) return true; 1340 1341 // If the source library's module id is in the dependent library list of the 1342 // destination library, remove it since that module is now linked in. 1343 sys::Path modId; 1344 modId.set(Src->getModuleIdentifier()); 1345 if (!modId.isEmpty()) 1346 Dest->removeLibrary(modId.getBasename()); 1347 1348 return false; 1349} 1350 1351// vim: sw=2 1352