LinkModules.cpp revision a7235ea7245028a0723e8ab7fd011386b3900777
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 ConstantArray::get(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 ConstantStruct::get(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 = ConstantVector::get(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(); 540 541 // Loop over all of the globals in the src module, mapping them over as we go 542 for (Module::const_global_iterator I = Src->global_begin(), 543 E = Src->global_end(); I != E; ++I) { 544 const GlobalVariable *SGV = I; 545 GlobalValue *DGV = 0; 546 547 // Check to see if may have to link the global with the global, alias or 548 // function. 549 if (SGV->hasName() && !SGV->hasLocalLinkage()) 550 DGV = cast_or_null<GlobalValue>(DestSymTab.lookup(SGV->getName())); 551 552 // If we found a global with the same name in the dest module, but it has 553 // internal linkage, we are really not doing any linkage here. 554 if (DGV && DGV->hasLocalLinkage()) 555 DGV = 0; 556 557 // If types don't agree due to opaque types, try to resolve them. 558 if (DGV && DGV->getType() != SGV->getType()) 559 RecursiveResolveTypes(SGV->getType(), DGV->getType()); 560 561 assert((SGV->hasInitializer() || SGV->hasExternalWeakLinkage() || 562 SGV->hasExternalLinkage() || SGV->hasDLLImportLinkage()) && 563 "Global must either be external or have an initializer!"); 564 565 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; 566 bool LinkFromSrc = false; 567 if (GetLinkageResult(DGV, SGV, NewLinkage, LinkFromSrc, Err)) 568 return true; 569 570 if (DGV == 0) { 571 // No linking to be performed, simply create an identical version of the 572 // symbol over in the dest module... the initializer will be filled in 573 // later by LinkGlobalInits. 574 GlobalVariable *NewDGV = 575 new GlobalVariable(*Dest, SGV->getType()->getElementType(), 576 SGV->isConstant(), SGV->getLinkage(), /*init*/0, 577 SGV->getName(), 0, false, 578 SGV->getType()->getAddressSpace()); 579 // Propagate alignment, visibility and section info. 580 CopyGVAttributes(NewDGV, SGV); 581 582 // If the LLVM runtime renamed the global, but it is an externally visible 583 // symbol, DGV must be an existing global with internal linkage. Rename 584 // it. 585 if (!NewDGV->hasLocalLinkage() && NewDGV->getName() != SGV->getName()) 586 ForceRenaming(NewDGV, SGV->getName()); 587 588 // Make sure to remember this mapping. 589 ValueMap[SGV] = NewDGV; 590 591 // Keep track that this is an appending variable. 592 if (SGV->hasAppendingLinkage()) 593 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV)); 594 continue; 595 } 596 597 // If the visibilities of the symbols disagree and the destination is a 598 // prototype, take the visibility of its input. 599 if (DGV->isDeclaration()) 600 DGV->setVisibility(SGV->getVisibility()); 601 602 if (DGV->hasAppendingLinkage()) { 603 // No linking is performed yet. Just insert a new copy of the global, and 604 // keep track of the fact that it is an appending variable in the 605 // AppendingVars map. The name is cleared out so that no linkage is 606 // performed. 607 GlobalVariable *NewDGV = 608 new GlobalVariable(*Dest, SGV->getType()->getElementType(), 609 SGV->isConstant(), SGV->getLinkage(), /*init*/0, 610 "", 0, false, 611 SGV->getType()->getAddressSpace()); 612 613 // Set alignment allowing CopyGVAttributes merge it with alignment of SGV. 614 NewDGV->setAlignment(DGV->getAlignment()); 615 // Propagate alignment, section and visibility info. 616 CopyGVAttributes(NewDGV, SGV); 617 618 // Make sure to remember this mapping... 619 ValueMap[SGV] = NewDGV; 620 621 // Keep track that this is an appending variable... 622 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV)); 623 continue; 624 } 625 626 if (LinkFromSrc) { 627 if (isa<GlobalAlias>(DGV)) 628 return Error(Err, "Global-Alias Collision on '" + SGV->getName() + 629 "': symbol multiple defined"); 630 631 // If the types don't match, and if we are to link from the source, nuke 632 // DGV and create a new one of the appropriate type. Note that the thing 633 // we are replacing may be a function (if a prototype, weak, etc) or a 634 // global variable. 635 GlobalVariable *NewDGV = 636 new GlobalVariable(*Dest, SGV->getType()->getElementType(), 637 SGV->isConstant(), NewLinkage, /*init*/0, 638 DGV->getName(), 0, false, 639 SGV->getType()->getAddressSpace()); 640 641 // Propagate alignment, section, and visibility info. 642 CopyGVAttributes(NewDGV, SGV); 643 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDGV, 644 DGV->getType())); 645 646 // DGV will conflict with NewDGV because they both had the same 647 // name. We must erase this now so ForceRenaming doesn't assert 648 // because DGV might not have internal linkage. 649 if (GlobalVariable *Var = dyn_cast<GlobalVariable>(DGV)) 650 Var->eraseFromParent(); 651 else 652 cast<Function>(DGV)->eraseFromParent(); 653 DGV = NewDGV; 654 655 // If the symbol table renamed the global, but it is an externally visible 656 // symbol, DGV must be an existing global with internal linkage. Rename. 657 if (NewDGV->getName() != SGV->getName() && !NewDGV->hasLocalLinkage()) 658 ForceRenaming(NewDGV, SGV->getName()); 659 660 // Inherit const as appropriate. 661 NewDGV->setConstant(SGV->isConstant()); 662 663 // Make sure to remember this mapping. 664 ValueMap[SGV] = NewDGV; 665 continue; 666 } 667 668 // Not "link from source", keep the one in the DestModule and remap the 669 // input onto it. 670 671 // Special case for const propagation. 672 if (GlobalVariable *DGVar = dyn_cast<GlobalVariable>(DGV)) 673 if (DGVar->isDeclaration() && SGV->isConstant() && !DGVar->isConstant()) 674 DGVar->setConstant(true); 675 676 // SGV is global, but DGV is alias. 677 if (isa<GlobalAlias>(DGV)) { 678 // The only valid mappings are: 679 // - SGV is external declaration, which is effectively a no-op. 680 // - SGV is weak, when we just need to throw SGV out. 681 if (!SGV->isDeclaration() && !SGV->isWeakForLinker()) 682 return Error(Err, "Global-Alias Collision on '" + SGV->getName() + 683 "': symbol multiple defined"); 684 } 685 686 // Set calculated linkage 687 DGV->setLinkage(NewLinkage); 688 689 // Make sure to remember this mapping... 690 ValueMap[SGV] = ConstantExpr::getBitCast(DGV, SGV->getType()); 691 } 692 return false; 693} 694 695static GlobalValue::LinkageTypes 696CalculateAliasLinkage(const GlobalValue *SGV, const GlobalValue *DGV) { 697 GlobalValue::LinkageTypes SL = SGV->getLinkage(); 698 GlobalValue::LinkageTypes DL = DGV->getLinkage(); 699 if (SL == GlobalValue::ExternalLinkage || DL == GlobalValue::ExternalLinkage) 700 return GlobalValue::ExternalLinkage; 701 else if (SL == GlobalValue::WeakAnyLinkage || 702 DL == GlobalValue::WeakAnyLinkage) 703 return GlobalValue::WeakAnyLinkage; 704 else if (SL == GlobalValue::WeakODRLinkage || 705 DL == GlobalValue::WeakODRLinkage) 706 return GlobalValue::WeakODRLinkage; 707 else if (SL == GlobalValue::InternalLinkage && 708 DL == GlobalValue::InternalLinkage) 709 return GlobalValue::InternalLinkage; 710 else if (SL == GlobalValue::LinkerPrivateLinkage && 711 DL == GlobalValue::LinkerPrivateLinkage) 712 return GlobalValue::LinkerPrivateLinkage; 713 else { 714 assert (SL == GlobalValue::PrivateLinkage && 715 DL == GlobalValue::PrivateLinkage && "Unexpected linkage type"); 716 return GlobalValue::PrivateLinkage; 717 } 718} 719 720// LinkAlias - Loop through the alias in the src module and link them into the 721// dest module. We're assuming, that all functions/global variables were already 722// linked in. 723static bool LinkAlias(Module *Dest, const Module *Src, 724 std::map<const Value*, Value*> &ValueMap, 725 std::string *Err) { 726 // Loop over all alias in the src module 727 for (Module::const_alias_iterator I = Src->alias_begin(), 728 E = Src->alias_end(); I != E; ++I) { 729 const GlobalAlias *SGA = I; 730 const GlobalValue *SAliasee = SGA->getAliasedGlobal(); 731 GlobalAlias *NewGA = NULL; 732 733 // Globals were already linked, thus we can just query ValueMap for variant 734 // of SAliasee in Dest. 735 std::map<const Value*,Value*>::const_iterator VMI = ValueMap.find(SAliasee); 736 assert(VMI != ValueMap.end() && "Aliasee not linked"); 737 GlobalValue* DAliasee = cast<GlobalValue>(VMI->second); 738 GlobalValue* DGV = NULL; 739 740 // Try to find something 'similar' to SGA in destination module. 741 if (!DGV && !SGA->hasLocalLinkage()) { 742 DGV = Dest->getNamedAlias(SGA->getName()); 743 744 // If types don't agree due to opaque types, try to resolve them. 745 if (DGV && DGV->getType() != SGA->getType()) 746 RecursiveResolveTypes(SGA->getType(), DGV->getType()); 747 } 748 749 if (!DGV && !SGA->hasLocalLinkage()) { 750 DGV = Dest->getGlobalVariable(SGA->getName()); 751 752 // If types don't agree due to opaque types, try to resolve them. 753 if (DGV && DGV->getType() != SGA->getType()) 754 RecursiveResolveTypes(SGA->getType(), DGV->getType()); 755 } 756 757 if (!DGV && !SGA->hasLocalLinkage()) { 758 DGV = Dest->getFunction(SGA->getName()); 759 760 // If types don't agree due to opaque types, try to resolve them. 761 if (DGV && DGV->getType() != SGA->getType()) 762 RecursiveResolveTypes(SGA->getType(), DGV->getType()); 763 } 764 765 // No linking to be performed on internal stuff. 766 if (DGV && DGV->hasLocalLinkage()) 767 DGV = NULL; 768 769 if (GlobalAlias *DGA = dyn_cast_or_null<GlobalAlias>(DGV)) { 770 // Types are known to be the same, check whether aliasees equal. As 771 // globals are already linked we just need query ValueMap to find the 772 // mapping. 773 if (DAliasee == DGA->getAliasedGlobal()) { 774 // This is just two copies of the same alias. Propagate linkage, if 775 // necessary. 776 DGA->setLinkage(CalculateAliasLinkage(SGA, DGA)); 777 778 NewGA = DGA; 779 // Proceed to 'common' steps 780 } else 781 return Error(Err, "Alias Collision on '" + SGA->getName()+ 782 "': aliases have different aliasees"); 783 } else if (GlobalVariable *DGVar = dyn_cast_or_null<GlobalVariable>(DGV)) { 784 // The only allowed way is to link alias with external declaration or weak 785 // symbol.. 786 if (DGVar->isDeclaration() || DGVar->isWeakForLinker()) { 787 // But only if aliasee is global too... 788 if (!isa<GlobalVariable>(DAliasee)) 789 return Error(Err, "Global-Alias Collision on '" + SGA->getName() + 790 "': aliasee is not global variable"); 791 792 NewGA = new GlobalAlias(SGA->getType(), SGA->getLinkage(), 793 SGA->getName(), DAliasee, Dest); 794 CopyGVAttributes(NewGA, SGA); 795 796 // Any uses of DGV need to change to NewGA, with cast, if needed. 797 if (SGA->getType() != DGVar->getType()) 798 DGVar->replaceAllUsesWith(ConstantExpr::getBitCast(NewGA, 799 DGVar->getType())); 800 else 801 DGVar->replaceAllUsesWith(NewGA); 802 803 // DGVar will conflict with NewGA because they both had the same 804 // name. We must erase this now so ForceRenaming doesn't assert 805 // because DGV might not have internal linkage. 806 DGVar->eraseFromParent(); 807 808 // Proceed to 'common' steps 809 } else 810 return Error(Err, "Global-Alias Collision on '" + SGA->getName() + 811 "': symbol multiple defined"); 812 } else if (Function *DF = dyn_cast_or_null<Function>(DGV)) { 813 // The only allowed way is to link alias with external declaration or weak 814 // symbol... 815 if (DF->isDeclaration() || DF->isWeakForLinker()) { 816 // But only if aliasee is function too... 817 if (!isa<Function>(DAliasee)) 818 return Error(Err, "Function-Alias Collision on '" + SGA->getName() + 819 "': aliasee is not function"); 820 821 NewGA = new GlobalAlias(SGA->getType(), SGA->getLinkage(), 822 SGA->getName(), DAliasee, Dest); 823 CopyGVAttributes(NewGA, SGA); 824 825 // Any uses of DF need to change to NewGA, with cast, if needed. 826 if (SGA->getType() != DF->getType()) 827 DF->replaceAllUsesWith(ConstantExpr::getBitCast(NewGA, 828 DF->getType())); 829 else 830 DF->replaceAllUsesWith(NewGA); 831 832 // DF will conflict with NewGA because they both had the same 833 // name. We must erase this now so ForceRenaming doesn't assert 834 // because DF might not have internal linkage. 835 DF->eraseFromParent(); 836 837 // Proceed to 'common' steps 838 } else 839 return Error(Err, "Function-Alias Collision on '" + SGA->getName() + 840 "': symbol multiple defined"); 841 } else { 842 // No linking to be performed, simply create an identical version of the 843 // alias over in the dest module... 844 845 NewGA = new GlobalAlias(SGA->getType(), SGA->getLinkage(), 846 SGA->getName(), DAliasee, Dest); 847 CopyGVAttributes(NewGA, SGA); 848 849 // Proceed to 'common' steps 850 } 851 852 assert(NewGA && "No alias was created in destination module!"); 853 854 // If the symbol table renamed the alias, but it is an externally visible 855 // symbol, DGA must be an global value with internal linkage. Rename it. 856 if (NewGA->getName() != SGA->getName() && 857 !NewGA->hasLocalLinkage()) 858 ForceRenaming(NewGA, SGA->getName()); 859 860 // Remember this mapping so uses in the source module get remapped 861 // later by RemapOperand. 862 ValueMap[SGA] = NewGA; 863 } 864 865 return false; 866} 867 868 869// LinkGlobalInits - Update the initializers in the Dest module now that all 870// globals that may be referenced are in Dest. 871static bool LinkGlobalInits(Module *Dest, const Module *Src, 872 std::map<const Value*, Value*> &ValueMap, 873 std::string *Err) { 874 // Loop over all of the globals in the src module, mapping them over as we go 875 for (Module::const_global_iterator I = Src->global_begin(), 876 E = Src->global_end(); I != E; ++I) { 877 const GlobalVariable *SGV = I; 878 879 if (SGV->hasInitializer()) { // Only process initialized GV's 880 // Figure out what the initializer looks like in the dest module... 881 Constant *SInit = 882 cast<Constant>(RemapOperand(SGV->getInitializer(), ValueMap, 883 Dest->getContext())); 884 // Grab destination global variable or alias. 885 GlobalValue *DGV = cast<GlobalValue>(ValueMap[SGV]->stripPointerCasts()); 886 887 // If dest if global variable, check that initializers match. 888 if (GlobalVariable *DGVar = dyn_cast<GlobalVariable>(DGV)) { 889 if (DGVar->hasInitializer()) { 890 if (SGV->hasExternalLinkage()) { 891 if (DGVar->getInitializer() != SInit) 892 return Error(Err, "Global Variable Collision on '" + 893 SGV->getName() + 894 "': global variables have different initializers"); 895 } else if (DGVar->isWeakForLinker()) { 896 // Nothing is required, mapped values will take the new global 897 // automatically. 898 } else if (SGV->isWeakForLinker()) { 899 // Nothing is required, mapped values will take the new global 900 // automatically. 901 } else if (DGVar->hasAppendingLinkage()) { 902 llvm_unreachable("Appending linkage unimplemented!"); 903 } else { 904 llvm_unreachable("Unknown linkage!"); 905 } 906 } else { 907 // Copy the initializer over now... 908 DGVar->setInitializer(SInit); 909 } 910 } else { 911 // Destination is alias, the only valid situation is when source is 912 // weak. Also, note, that we already checked linkage in LinkGlobals(), 913 // thus we assert here. 914 // FIXME: Should we weaken this assumption, 'dereference' alias and 915 // check for initializer of aliasee? 916 assert(SGV->isWeakForLinker()); 917 } 918 } 919 } 920 return false; 921} 922 923// LinkFunctionProtos - Link the functions together between the two modules, 924// without doing function bodies... this just adds external function prototypes 925// to the Dest function... 926// 927static bool LinkFunctionProtos(Module *Dest, const Module *Src, 928 std::map<const Value*, Value*> &ValueMap, 929 std::string *Err) { 930 ValueSymbolTable &DestSymTab = Dest->getValueSymbolTable(); 931 932 // Loop over all of the functions in the src module, mapping them over 933 for (Module::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) { 934 const Function *SF = I; // SrcFunction 935 GlobalValue *DGV = 0; 936 937 // Check to see if may have to link the function with the global, alias or 938 // function. 939 if (SF->hasName() && !SF->hasLocalLinkage()) 940 DGV = cast_or_null<GlobalValue>(DestSymTab.lookup(SF->getName())); 941 942 // If we found a global with the same name in the dest module, but it has 943 // internal linkage, we are really not doing any linkage here. 944 if (DGV && DGV->hasLocalLinkage()) 945 DGV = 0; 946 947 // If types don't agree due to opaque types, try to resolve them. 948 if (DGV && DGV->getType() != SF->getType()) 949 RecursiveResolveTypes(SF->getType(), DGV->getType()); 950 951 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; 952 bool LinkFromSrc = false; 953 if (GetLinkageResult(DGV, SF, NewLinkage, LinkFromSrc, Err)) 954 return true; 955 956 // If there is no linkage to be performed, just bring over SF without 957 // modifying it. 958 if (DGV == 0) { 959 // Function does not already exist, simply insert an function signature 960 // identical to SF into the dest module. 961 Function *NewDF = Function::Create(SF->getFunctionType(), 962 SF->getLinkage(), 963 SF->getName(), Dest); 964 CopyGVAttributes(NewDF, SF); 965 966 // If the LLVM runtime renamed the function, but it is an externally 967 // visible symbol, DF must be an existing function with internal linkage. 968 // Rename it. 969 if (!NewDF->hasLocalLinkage() && NewDF->getName() != SF->getName()) 970 ForceRenaming(NewDF, SF->getName()); 971 972 // ... and remember this mapping... 973 ValueMap[SF] = NewDF; 974 continue; 975 } 976 977 // If the visibilities of the symbols disagree and the destination is a 978 // prototype, take the visibility of its input. 979 if (DGV->isDeclaration()) 980 DGV->setVisibility(SF->getVisibility()); 981 982 if (LinkFromSrc) { 983 if (isa<GlobalAlias>(DGV)) 984 return Error(Err, "Function-Alias Collision on '" + SF->getName() + 985 "': symbol multiple defined"); 986 987 // We have a definition of the same name but different type in the 988 // source module. Copy the prototype to the destination and replace 989 // uses of the destination's prototype with the new prototype. 990 Function *NewDF = Function::Create(SF->getFunctionType(), NewLinkage, 991 SF->getName(), Dest); 992 CopyGVAttributes(NewDF, SF); 993 994 // Any uses of DF need to change to NewDF, with cast 995 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDF, 996 DGV->getType())); 997 998 // DF will conflict with NewDF because they both had the same. We must 999 // erase this now so ForceRenaming doesn't assert because DF might 1000 // not have internal linkage. 1001 if (GlobalVariable *Var = dyn_cast<GlobalVariable>(DGV)) 1002 Var->eraseFromParent(); 1003 else 1004 cast<Function>(DGV)->eraseFromParent(); 1005 1006 // If the symbol table renamed the function, but it is an externally 1007 // visible symbol, DF must be an existing function with internal 1008 // linkage. Rename it. 1009 if (NewDF->getName() != SF->getName() && !NewDF->hasLocalLinkage()) 1010 ForceRenaming(NewDF, SF->getName()); 1011 1012 // Remember this mapping so uses in the source module get remapped 1013 // later by RemapOperand. 1014 ValueMap[SF] = NewDF; 1015 continue; 1016 } 1017 1018 // Not "link from source", keep the one in the DestModule and remap the 1019 // input onto it. 1020 1021 if (isa<GlobalAlias>(DGV)) { 1022 // The only valid mappings are: 1023 // - SF is external declaration, which is effectively a no-op. 1024 // - SF is weak, when we just need to throw SF out. 1025 if (!SF->isDeclaration() && !SF->isWeakForLinker()) 1026 return Error(Err, "Function-Alias Collision on '" + SF->getName() + 1027 "': symbol multiple defined"); 1028 } 1029 1030 // Set calculated linkage 1031 DGV->setLinkage(NewLinkage); 1032 1033 // Make sure to remember this mapping. 1034 ValueMap[SF] = ConstantExpr::getBitCast(DGV, SF->getType()); 1035 } 1036 return false; 1037} 1038 1039// LinkFunctionBody - Copy the source function over into the dest function and 1040// fix up references to values. At this point we know that Dest is an external 1041// function, and that Src is not. 1042static bool LinkFunctionBody(Function *Dest, Function *Src, 1043 std::map<const Value*, Value*> &ValueMap, 1044 std::string *Err) { 1045 assert(Src && Dest && Dest->isDeclaration() && !Src->isDeclaration()); 1046 1047 // Go through and convert function arguments over, remembering the mapping. 1048 Function::arg_iterator DI = Dest->arg_begin(); 1049 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end(); 1050 I != E; ++I, ++DI) { 1051 DI->setName(I->getName()); // Copy the name information over... 1052 1053 // Add a mapping to our local map 1054 ValueMap[I] = DI; 1055 } 1056 1057 // Splice the body of the source function into the dest function. 1058 Dest->getBasicBlockList().splice(Dest->end(), Src->getBasicBlockList()); 1059 1060 // At this point, all of the instructions and values of the function are now 1061 // copied over. The only problem is that they are still referencing values in 1062 // the Source function as operands. Loop through all of the operands of the 1063 // functions and patch them up to point to the local versions... 1064 // 1065 for (Function::iterator BB = Dest->begin(), BE = Dest->end(); BB != BE; ++BB) 1066 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) 1067 for (Instruction::op_iterator OI = I->op_begin(), OE = I->op_end(); 1068 OI != OE; ++OI) 1069 if (!isa<Instruction>(*OI) && !isa<BasicBlock>(*OI)) 1070 *OI = RemapOperand(*OI, ValueMap, Dest->getContext()); 1071 1072 // There is no need to map the arguments anymore. 1073 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end(); 1074 I != E; ++I) 1075 ValueMap.erase(I); 1076 1077 return false; 1078} 1079 1080 1081// LinkFunctionBodies - Link in the function bodies that are defined in the 1082// source module into the DestModule. This consists basically of copying the 1083// function over and fixing up references to values. 1084static bool LinkFunctionBodies(Module *Dest, Module *Src, 1085 std::map<const Value*, Value*> &ValueMap, 1086 std::string *Err) { 1087 1088 // Loop over all of the functions in the src module, mapping them over as we 1089 // go 1090 for (Module::iterator SF = Src->begin(), E = Src->end(); SF != E; ++SF) { 1091 if (!SF->isDeclaration()) { // No body if function is external 1092 Function *DF = dyn_cast<Function>(ValueMap[SF]); // Destination function 1093 1094 // DF not external SF external? 1095 if (DF && DF->isDeclaration()) 1096 // Only provide the function body if there isn't one already. 1097 if (LinkFunctionBody(DF, SF, ValueMap, Err)) 1098 return true; 1099 } 1100 } 1101 return false; 1102} 1103 1104// LinkAppendingVars - If there were any appending global variables, link them 1105// together now. Return true on error. 1106static bool LinkAppendingVars(Module *M, 1107 std::multimap<std::string, GlobalVariable *> &AppendingVars, 1108 std::string *ErrorMsg) { 1109 if (AppendingVars.empty()) return false; // Nothing to do. 1110 1111 // Loop over the multimap of appending vars, processing any variables with the 1112 // same name, forming a new appending global variable with both of the 1113 // initializers merged together, then rewrite references to the old variables 1114 // and delete them. 1115 std::vector<Constant*> Inits; 1116 while (AppendingVars.size() > 1) { 1117 // Get the first two elements in the map... 1118 std::multimap<std::string, 1119 GlobalVariable*>::iterator Second = AppendingVars.begin(), First=Second++; 1120 1121 // If the first two elements are for different names, there is no pair... 1122 // Otherwise there is a pair, so link them together... 1123 if (First->first == Second->first) { 1124 GlobalVariable *G1 = First->second, *G2 = Second->second; 1125 const ArrayType *T1 = cast<ArrayType>(G1->getType()->getElementType()); 1126 const ArrayType *T2 = cast<ArrayType>(G2->getType()->getElementType()); 1127 1128 // Check to see that they two arrays agree on type... 1129 if (T1->getElementType() != T2->getElementType()) 1130 return Error(ErrorMsg, 1131 "Appending variables with different element types need to be linked!"); 1132 if (G1->isConstant() != G2->isConstant()) 1133 return Error(ErrorMsg, 1134 "Appending variables linked with different const'ness!"); 1135 1136 if (G1->getAlignment() != G2->getAlignment()) 1137 return Error(ErrorMsg, 1138 "Appending variables with different alignment need to be linked!"); 1139 1140 if (G1->getVisibility() != G2->getVisibility()) 1141 return Error(ErrorMsg, 1142 "Appending variables with different visibility need to be linked!"); 1143 1144 if (G1->getSection() != G2->getSection()) 1145 return Error(ErrorMsg, 1146 "Appending variables with different section name need to be linked!"); 1147 1148 unsigned NewSize = T1->getNumElements() + T2->getNumElements(); 1149 ArrayType *NewType = ArrayType::get(T1->getElementType(), 1150 NewSize); 1151 1152 G1->setName(""); // Clear G1's name in case of a conflict! 1153 1154 // Create the new global variable... 1155 GlobalVariable *NG = 1156 new GlobalVariable(*M, NewType, G1->isConstant(), G1->getLinkage(), 1157 /*init*/0, First->first, 0, G1->isThreadLocal(), 1158 G1->getType()->getAddressSpace()); 1159 1160 // Propagate alignment, visibility and section info. 1161 CopyGVAttributes(NG, G1); 1162 1163 // Merge the initializer... 1164 Inits.reserve(NewSize); 1165 if (ConstantArray *I = dyn_cast<ConstantArray>(G1->getInitializer())) { 1166 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i) 1167 Inits.push_back(I->getOperand(i)); 1168 } else { 1169 assert(isa<ConstantAggregateZero>(G1->getInitializer())); 1170 Constant *CV = Constant::getNullValue(T1->getElementType()); 1171 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i) 1172 Inits.push_back(CV); 1173 } 1174 if (ConstantArray *I = dyn_cast<ConstantArray>(G2->getInitializer())) { 1175 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i) 1176 Inits.push_back(I->getOperand(i)); 1177 } else { 1178 assert(isa<ConstantAggregateZero>(G2->getInitializer())); 1179 Constant *CV = Constant::getNullValue(T2->getElementType()); 1180 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i) 1181 Inits.push_back(CV); 1182 } 1183 NG->setInitializer(ConstantArray::get(NewType, Inits)); 1184 Inits.clear(); 1185 1186 // Replace any uses of the two global variables with uses of the new 1187 // global... 1188 1189 // FIXME: This should rewrite simple/straight-forward uses such as 1190 // getelementptr instructions to not use the Cast! 1191 G1->replaceAllUsesWith(ConstantExpr::getBitCast(NG, 1192 G1->getType())); 1193 G2->replaceAllUsesWith(ConstantExpr::getBitCast(NG, 1194 G2->getType())); 1195 1196 // Remove the two globals from the module now... 1197 M->getGlobalList().erase(G1); 1198 M->getGlobalList().erase(G2); 1199 1200 // Put the new global into the AppendingVars map so that we can handle 1201 // linking of more than two vars... 1202 Second->second = NG; 1203 } 1204 AppendingVars.erase(First); 1205 } 1206 1207 return false; 1208} 1209 1210static bool ResolveAliases(Module *Dest) { 1211 for (Module::alias_iterator I = Dest->alias_begin(), E = Dest->alias_end(); 1212 I != E; ++I) 1213 if (const GlobalValue *GV = I->resolveAliasedGlobal()) 1214 if (GV != I && !GV->isDeclaration()) 1215 I->replaceAllUsesWith(const_cast<GlobalValue*>(GV)); 1216 1217 return false; 1218} 1219 1220// LinkModules - This function links two modules together, with the resulting 1221// left module modified to be the composite of the two input modules. If an 1222// error occurs, true is returned and ErrorMsg (if not null) is set to indicate 1223// the problem. Upon failure, the Dest module could be in a modified state, and 1224// shouldn't be relied on to be consistent. 1225bool 1226Linker::LinkModules(Module *Dest, Module *Src, std::string *ErrorMsg) { 1227 assert(Dest != 0 && "Invalid Destination module"); 1228 assert(Src != 0 && "Invalid Source Module"); 1229 1230 if (Dest->getDataLayout().empty()) { 1231 if (!Src->getDataLayout().empty()) { 1232 Dest->setDataLayout(Src->getDataLayout()); 1233 } else { 1234 std::string DataLayout; 1235 1236 if (Dest->getEndianness() == Module::AnyEndianness) { 1237 if (Src->getEndianness() == Module::BigEndian) 1238 DataLayout.append("E"); 1239 else if (Src->getEndianness() == Module::LittleEndian) 1240 DataLayout.append("e"); 1241 } 1242 1243 if (Dest->getPointerSize() == Module::AnyPointerSize) { 1244 if (Src->getPointerSize() == Module::Pointer64) 1245 DataLayout.append(DataLayout.length() == 0 ? "p:64:64" : "-p:64:64"); 1246 else if (Src->getPointerSize() == Module::Pointer32) 1247 DataLayout.append(DataLayout.length() == 0 ? "p:32:32" : "-p:32:32"); 1248 } 1249 Dest->setDataLayout(DataLayout); 1250 } 1251 } 1252 1253 // Copy the target triple from the source to dest if the dest's is empty. 1254 if (Dest->getTargetTriple().empty() && !Src->getTargetTriple().empty()) 1255 Dest->setTargetTriple(Src->getTargetTriple()); 1256 1257 if (!Src->getDataLayout().empty() && !Dest->getDataLayout().empty() && 1258 Src->getDataLayout() != Dest->getDataLayout()) 1259 cerr << "WARNING: Linking two modules of different data layouts!\n"; 1260 if (!Src->getTargetTriple().empty() && 1261 Dest->getTargetTriple() != Src->getTargetTriple()) 1262 cerr << "WARNING: Linking two modules of different target triples!\n"; 1263 1264 // Append the module inline asm string. 1265 if (!Src->getModuleInlineAsm().empty()) { 1266 if (Dest->getModuleInlineAsm().empty()) 1267 Dest->setModuleInlineAsm(Src->getModuleInlineAsm()); 1268 else 1269 Dest->setModuleInlineAsm(Dest->getModuleInlineAsm()+"\n"+ 1270 Src->getModuleInlineAsm()); 1271 } 1272 1273 // Update the destination module's dependent libraries list with the libraries 1274 // from the source module. There's no opportunity for duplicates here as the 1275 // Module ensures that duplicate insertions are discarded. 1276 for (Module::lib_iterator SI = Src->lib_begin(), SE = Src->lib_end(); 1277 SI != SE; ++SI) 1278 Dest->addLibrary(*SI); 1279 1280 // LinkTypes - Go through the symbol table of the Src module and see if any 1281 // types are named in the src module that are not named in the Dst module. 1282 // Make sure there are no type name conflicts. 1283 if (LinkTypes(Dest, Src, ErrorMsg)) 1284 return true; 1285 1286 // ValueMap - Mapping of values from what they used to be in Src, to what they 1287 // are now in Dest. 1288 std::map<const Value*, Value*> ValueMap; 1289 1290 // AppendingVars - Keep track of global variables in the destination module 1291 // with appending linkage. After the module is linked together, they are 1292 // appended and the module is rewritten. 1293 std::multimap<std::string, GlobalVariable *> AppendingVars; 1294 for (Module::global_iterator I = Dest->global_begin(), E = Dest->global_end(); 1295 I != E; ++I) { 1296 // Add all of the appending globals already in the Dest module to 1297 // AppendingVars. 1298 if (I->hasAppendingLinkage()) 1299 AppendingVars.insert(std::make_pair(I->getName(), I)); 1300 } 1301 1302 // Insert all of the globals in src into the Dest module... without linking 1303 // initializers (which could refer to functions not yet mapped over). 1304 if (LinkGlobals(Dest, Src, ValueMap, AppendingVars, ErrorMsg)) 1305 return true; 1306 1307 // Link the functions together between the two modules, without doing function 1308 // bodies... this just adds external function prototypes to the Dest 1309 // function... We do this so that when we begin processing function bodies, 1310 // all of the global values that may be referenced are available in our 1311 // ValueMap. 1312 if (LinkFunctionProtos(Dest, Src, ValueMap, ErrorMsg)) 1313 return true; 1314 1315 // If there were any alias, link them now. We really need to do this now, 1316 // because all of the aliases that may be referenced need to be available in 1317 // ValueMap 1318 if (LinkAlias(Dest, Src, ValueMap, ErrorMsg)) return true; 1319 1320 // Update the initializers in the Dest module now that all globals that may 1321 // be referenced are in Dest. 1322 if (LinkGlobalInits(Dest, Src, ValueMap, ErrorMsg)) return true; 1323 1324 // Link in the function bodies that are defined in the source module into the 1325 // DestModule. This consists basically of copying the function over and 1326 // fixing up references to values. 1327 if (LinkFunctionBodies(Dest, Src, ValueMap, ErrorMsg)) return true; 1328 1329 // If there were any appending global variables, link them together now. 1330 if (LinkAppendingVars(Dest, AppendingVars, ErrorMsg)) return true; 1331 1332 // Resolve all uses of aliases with aliasees 1333 if (ResolveAliases(Dest)) return true; 1334 1335 // If the source library's module id is in the dependent library list of the 1336 // destination library, remove it since that module is now linked in. 1337 sys::Path modId; 1338 modId.set(Src->getModuleIdentifier()); 1339 if (!modId.isEmpty()) 1340 Dest->removeLibrary(modId.getBasename()); 1341 1342 return false; 1343} 1344 1345// vim: sw=2 1346