LinkModules.cpp revision 0b228bf4315ee36f591046c309cb213f7c1197c0
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/Module.h" 23#include "llvm/TypeSymbolTable.h" 24#include "llvm/ValueSymbolTable.h" 25#include "llvm/Instructions.h" 26#include "llvm/Assembly/Writer.h" 27#include "llvm/Support/Streams.h" 28#include "llvm/System/Path.h" 29#include "llvm/ADT/DenseMap.h" 30#include <sstream> 31using namespace llvm; 32 33// Error - Simple wrapper function to conditionally assign to E and return true. 34// This just makes error return conditions a little bit simpler... 35static inline bool Error(std::string *E, const std::string &Message) { 36 if (E) *E = Message; 37 return true; 38} 39 40// ToStr - Simple wrapper function to convert a type to a string. 41static std::string ToStr(const Type *Ty, const Module *M) { 42 std::ostringstream OS; 43 WriteTypeSymbolic(OS, Ty, M); 44 return OS.str(); 45} 46 47// 48// Function: ResolveTypes() 49// 50// Description: 51// Attempt to link the two specified types together. 52// 53// Inputs: 54// DestTy - The type to which we wish to resolve. 55// SrcTy - The original type which we want to resolve. 56// 57// Outputs: 58// DestST - The symbol table in which the new type should be placed. 59// 60// Return value: 61// true - There is an error and the types cannot yet be linked. 62// false - No errors. 63// 64static bool ResolveTypes(const Type *DestTy, const Type *SrcTy) { 65 if (DestTy == SrcTy) return false; // If already equal, noop 66 assert(DestTy && SrcTy && "Can't handle null types"); 67 68 if (const OpaqueType *OT = dyn_cast<OpaqueType>(DestTy)) { 69 // Type _is_ in module, just opaque... 70 const_cast<OpaqueType*>(OT)->refineAbstractTypeTo(SrcTy); 71 } else if (const OpaqueType *OT = dyn_cast<OpaqueType>(SrcTy)) { 72 const_cast<OpaqueType*>(OT)->refineAbstractTypeTo(DestTy); 73 } else { 74 return true; // Cannot link types... not-equal and neither is opaque. 75 } 76 return false; 77} 78 79/// LinkerTypeMap - This implements a map of types that is stable 80/// even if types are resolved/refined to other types. This is not a general 81/// purpose map, it is specific to the linker's use. 82namespace { 83class LinkerTypeMap : public AbstractTypeUser { 84 typedef DenseMap<const Type*, PATypeHolder> TheMapTy; 85 TheMapTy TheMap; 86public: 87 88 LinkerTypeMap() { 89 for (DenseMap<const Type*, PATypeHolder>::iterator I = TheMap.begin(), 90 E = TheMap.end(); I != E; ++I) 91 I->first->removeAbstractTypeUser(this); 92 } 93 94 /// lookup - Return the value for the specified type or null if it doesn't 95 /// exist. 96 const Type *lookup(const Type *Ty) const { 97 TheMapTy::const_iterator I = TheMap.find(Ty); 98 if (I != TheMap.end()) return I->second; 99 return 0; 100 } 101 102 /// erase - Remove the specified type, returning true if it was in the set. 103 bool erase(const Type *Ty) { 104 if (!TheMap.erase(Ty)) 105 return false; 106 if (Ty->isAbstract()) 107 Ty->removeAbstractTypeUser(this); 108 return true; 109 } 110 111 /// insert - This returns true if the pointer was new to the set, false if it 112 /// was already in the set. 113 bool insert(const Type *Src, const Type *Dst) { 114 if (!TheMap.insert(std::make_pair(Src, PATypeHolder(Dst)))) 115 return false; // Already in map. 116 if (Src->isAbstract()) 117 Src->addAbstractTypeUser(this); 118 return true; 119 } 120 121protected: 122 /// refineAbstractType - The callback method invoked when an abstract type is 123 /// resolved to another type. An object must override this method to update 124 /// its internal state to reference NewType instead of OldType. 125 /// 126 virtual void refineAbstractType(const DerivedType *OldTy, 127 const Type *NewTy) { 128 TheMapTy::iterator I = TheMap.find(OldTy); 129 const Type *DstTy = I->second; 130 131 TheMap.erase(I); 132 if (OldTy->isAbstract()) 133 OldTy->removeAbstractTypeUser(this); 134 135 // Don't reinsert into the map if the key is concrete now. 136 if (NewTy->isAbstract()) 137 insert(NewTy, DstTy); 138 } 139 140 /// The other case which AbstractTypeUsers must be aware of is when a type 141 /// makes the transition from being abstract (where it has clients on it's 142 /// AbstractTypeUsers list) to concrete (where it does not). This method 143 /// notifies ATU's when this occurs for a type. 144 virtual void typeBecameConcrete(const DerivedType *AbsTy) { 145 TheMap.erase(AbsTy); 146 AbsTy->removeAbstractTypeUser(this); 147 } 148 149 // for debugging... 150 virtual void dump() const { 151 cerr << "AbstractTypeSet!\n"; 152 } 153}; 154} 155 156 157// RecursiveResolveTypes - This is just like ResolveTypes, except that it 158// recurses down into derived types, merging the used types if the parent types 159// are compatible. 160static bool RecursiveResolveTypesI(const PATypeHolder &DestTy, 161 const PATypeHolder &SrcTy, 162 LinkerTypeMap &Pointers) { 163 const Type *SrcTyT = SrcTy.get(); 164 const Type *DestTyT = DestTy.get(); 165 if (DestTyT == SrcTyT) return false; // If already equal, noop 166 167 // If we found our opaque type, resolve it now! 168 if (isa<OpaqueType>(DestTyT) || isa<OpaqueType>(SrcTyT)) 169 return ResolveTypes(DestTyT, SrcTyT); 170 171 // Two types cannot be resolved together if they are of different primitive 172 // type. For example, we cannot resolve an int to a float. 173 if (DestTyT->getTypeID() != SrcTyT->getTypeID()) return true; 174 175 // If neither type is abstract, then they really are just different types. 176 if (!DestTyT->isAbstract() && !SrcTyT->isAbstract()) 177 return true; 178 179 // Otherwise, resolve the used type used by this derived type... 180 switch (DestTyT->getTypeID()) { 181 default: 182 return true; 183 case Type::FunctionTyID: { 184 const FunctionType *DstFT = cast<FunctionType>(DestTyT); 185 const FunctionType *SrcFT = cast<FunctionType>(SrcTyT); 186 if (DstFT->isVarArg() != SrcFT->isVarArg() || 187 DstFT->getNumContainedTypes() != SrcFT->getNumContainedTypes()) 188 return true; 189 for (unsigned i = 0, e = DstFT->getNumContainedTypes(); i != e; ++i) 190 if (RecursiveResolveTypesI(DstFT->getContainedType(i), 191 SrcFT->getContainedType(i), Pointers)) 192 return true; 193 return false; 194 } 195 case Type::StructTyID: { 196 const StructType *DstST = cast<StructType>(DestTyT); 197 const StructType *SrcST = cast<StructType>(SrcTyT); 198 if (DstST->getNumContainedTypes() != SrcST->getNumContainedTypes()) 199 return true; 200 for (unsigned i = 0, e = DstST->getNumContainedTypes(); i != e; ++i) 201 if (RecursiveResolveTypesI(DstST->getContainedType(i), 202 SrcST->getContainedType(i), Pointers)) 203 return true; 204 return false; 205 } 206 case Type::ArrayTyID: { 207 const ArrayType *DAT = cast<ArrayType>(DestTy.get()); 208 const ArrayType *SAT = cast<ArrayType>(SrcTy.get()); 209 if (DAT->getNumElements() != SAT->getNumElements()) return true; 210 return RecursiveResolveTypesI(DAT->getElementType(), SAT->getElementType(), 211 Pointers); 212 } 213 case Type::VectorTyID: { 214 const VectorType *DVT = cast<VectorType>(DestTy.get()); 215 const VectorType *SVT = cast<VectorType>(SrcTy.get()); 216 if (DVT->getNumElements() != SVT->getNumElements()) return true; 217 return RecursiveResolveTypesI(DVT->getElementType(), SVT->getElementType(), 218 Pointers); 219 } 220 case Type::PointerTyID: { 221 const PointerType *DstPT = cast<PointerType>(DestTy.get()); 222 const PointerType *SrcPT = cast<PointerType>(SrcTy.get()); 223 224 if (DstPT->getAddressSpace() != SrcPT->getAddressSpace()) 225 return true; 226 227 // If this is a pointer type, check to see if we have already seen it. If 228 // so, we are in a recursive branch. Cut off the search now. We cannot use 229 // an associative container for this search, because the type pointers (keys 230 // in the container) change whenever types get resolved. 231 if (SrcPT->isAbstract()) 232 if (const Type *ExistingDestTy = Pointers.lookup(SrcPT)) 233 return ExistingDestTy != DstPT; 234 235 if (DstPT->isAbstract()) 236 if (const Type *ExistingSrcTy = Pointers.lookup(DstPT)) 237 return ExistingSrcTy != SrcPT; 238 239 // 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 return RecursiveResolveTypesI(DstPT->getElementType(), 246 SrcPT->getElementType(), Pointers); 247 } 248 } 249} 250 251static bool RecursiveResolveTypes(const PATypeHolder &DestTy, 252 const PATypeHolder &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 PATypeHolder T1(SrcST->lookup(Name)); 316 PATypeHolder T2(DestST->lookup(Name)); 317 318 if (!RecursiveResolveTypes(T2, T1)) { 319 // We are making progress! 320 DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i); 321 322 // Go back to the main loop, perhaps we can resolve directly by name 323 // now... 324 break; 325 } 326 } 327 328 // If we STILL cannot resolve the types, then there is something wrong. 329 if (DelayedTypesToResolve.size() == OldSize) { 330 // Remove the symbol name from the destination. 331 DelayedTypesToResolve.pop_back(); 332 } 333 } 334 } 335 336 337 return false; 338} 339 340static void PrintMap(const std::map<const Value*, Value*> &M) { 341 for (std::map<const Value*, Value*>::const_iterator I = M.begin(), E =M.end(); 342 I != E; ++I) { 343 cerr << " Fr: " << (void*)I->first << " "; 344 I->first->dump(); 345 cerr << " To: " << (void*)I->second << " "; 346 I->second->dump(); 347 cerr << "\n"; 348 } 349} 350 351 352// RemapOperand - Use ValueMap to convert constants from one module to another. 353static Value *RemapOperand(const Value *In, 354 std::map<const Value*, Value*> &ValueMap) { 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 Result = ConstantArray::get(cast<ArrayType>(CPA->getType()), Operands); 371 } else if (const ConstantStruct *CPS = dyn_cast<ConstantStruct>(CPV)) { 372 std::vector<Constant*> Operands(CPS->getNumOperands()); 373 for (unsigned i = 0, e = CPS->getNumOperands(); i != e; ++i) 374 Operands[i] =cast<Constant>(RemapOperand(CPS->getOperand(i), ValueMap)); 375 Result = ConstantStruct::get(cast<StructType>(CPS->getType()), Operands); 376 } else if (isa<ConstantPointerNull>(CPV) || isa<UndefValue>(CPV)) { 377 Result = const_cast<Constant*>(CPV); 378 } else if (const ConstantVector *CP = dyn_cast<ConstantVector>(CPV)) { 379 std::vector<Constant*> Operands(CP->getNumOperands()); 380 for (unsigned i = 0, e = CP->getNumOperands(); i != e; ++i) 381 Operands[i] = cast<Constant>(RemapOperand(CP->getOperand(i), ValueMap)); 382 Result = ConstantVector::get(Operands); 383 } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CPV)) { 384 std::vector<Constant*> Ops; 385 for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) 386 Ops.push_back(cast<Constant>(RemapOperand(CE->getOperand(i),ValueMap))); 387 Result = CE->getWithOperands(Ops); 388 } else if (isa<GlobalValue>(CPV)) { 389 assert(0 && "Unmapped global?"); 390 } else { 391 assert(0 && "Unknown type of derived type constant value!"); 392 } 393 } else if (isa<InlineAsm>(In)) { 394 Result = const_cast<Value*>(In); 395 } 396 397 // Cache the mapping in our local map structure 398 if (Result) { 399 ValueMap[In] = Result; 400 return Result; 401 } 402 403 404 cerr << "LinkModules ValueMap: \n"; 405 PrintMap(ValueMap); 406 407 cerr << "Couldn't remap value: " << (void*)In << " " << *In << "\n"; 408 assert(0 && "Couldn't remap value!"); 409 return 0; 410} 411 412/// ForceRenaming - The LLVM SymbolTable class autorenames globals that conflict 413/// in the symbol table. This is good for all clients except for us. Go 414/// through the trouble to force this back. 415static void ForceRenaming(GlobalValue *GV, const std::string &Name) { 416 assert(GV->getName() != Name && "Can't force rename to self"); 417 ValueSymbolTable &ST = GV->getParent()->getValueSymbolTable(); 418 419 // If there is a conflict, rename the conflict. 420 if (GlobalValue *ConflictGV = cast_or_null<GlobalValue>(ST.lookup(Name))) { 421 assert(ConflictGV->hasInternalLinkage() && 422 "Not conflicting with a static global, should link instead!"); 423 GV->takeName(ConflictGV); 424 ConflictGV->setName(Name); // This will cause ConflictGV to get renamed 425 assert(ConflictGV->getName() != Name && "ForceRenaming didn't work"); 426 } else { 427 GV->setName(Name); // Force the name back 428 } 429} 430 431/// CopyGVAttributes - copy additional attributes (those not needed to construct 432/// a GlobalValue) from the SrcGV to the DestGV. 433static void CopyGVAttributes(GlobalValue *DestGV, const GlobalValue *SrcGV) { 434 // Use the maximum alignment, rather than just copying the alignment of SrcGV. 435 unsigned Alignment = std::max(DestGV->getAlignment(), SrcGV->getAlignment()); 436 DestGV->copyAttributesFrom(SrcGV); 437 DestGV->setAlignment(Alignment); 438} 439 440/// GetLinkageResult - This analyzes the two global values and determines what 441/// the result will look like in the destination module. In particular, it 442/// computes the resultant linkage type, computes whether the global in the 443/// source should be copied over to the destination (replacing the existing 444/// one), and computes whether this linkage is an error or not. It also performs 445/// visibility checks: we cannot link together two symbols with different 446/// visibilities. 447static bool GetLinkageResult(GlobalValue *Dest, const GlobalValue *Src, 448 GlobalValue::LinkageTypes <, bool &LinkFromSrc, 449 std::string *Err) { 450 assert((!Dest || !Src->hasInternalLinkage()) && 451 "If Src has internal linkage, Dest shouldn't be set!"); 452 if (!Dest) { 453 // Linking something to nothing. 454 LinkFromSrc = true; 455 LT = Src->getLinkage(); 456 } else if (Src->isDeclaration()) { 457 // If Src is external or if both Src & Dest are external.. Just link the 458 // external globals, we aren't adding anything. 459 if (Src->hasDLLImportLinkage()) { 460 // If one of GVs has DLLImport linkage, result should be dllimport'ed. 461 if (Dest->isDeclaration()) { 462 LinkFromSrc = true; 463 LT = Src->getLinkage(); 464 } 465 } else if (Dest->hasExternalWeakLinkage()) { 466 //If the Dest is weak, use the source linkage 467 LinkFromSrc = true; 468 LT = Src->getLinkage(); 469 } else { 470 LinkFromSrc = false; 471 LT = Dest->getLinkage(); 472 } 473 } else if (Dest->isDeclaration() && !Dest->hasDLLImportLinkage()) { 474 // If Dest is external but Src is not: 475 LinkFromSrc = true; 476 LT = Src->getLinkage(); 477 } else if (Src->hasAppendingLinkage() || Dest->hasAppendingLinkage()) { 478 if (Src->getLinkage() != Dest->getLinkage()) 479 return Error(Err, "Linking globals named '" + Src->getName() + 480 "': can only link appending global with another appending global!"); 481 LinkFromSrc = true; // Special cased. 482 LT = Src->getLinkage(); 483 } else if (Src->hasWeakLinkage() || Src->hasLinkOnceLinkage() || 484 Src->hasCommonLinkage()) { 485 // At this point we know that Dest has LinkOnce, External*, Weak, Common, 486 // or DLL* linkage. 487 if ((Dest->hasLinkOnceLinkage() && 488 (Src->hasWeakLinkage() || Src->hasCommonLinkage())) || 489 Dest->hasExternalWeakLinkage()) { 490 LinkFromSrc = true; 491 LT = Src->getLinkage(); 492 } else { 493 LinkFromSrc = false; 494 LT = Dest->getLinkage(); 495 } 496 } else if (Dest->hasWeakLinkage() || Dest->hasLinkOnceLinkage() || 497 Dest->hasCommonLinkage()) { 498 // At this point we know that Src has External* or DLL* linkage. 499 if (Src->hasExternalWeakLinkage()) { 500 LinkFromSrc = false; 501 LT = Dest->getLinkage(); 502 } else { 503 LinkFromSrc = true; 504 LT = GlobalValue::ExternalLinkage; 505 } 506 } else { 507 assert((Dest->hasExternalLinkage() || 508 Dest->hasDLLImportLinkage() || 509 Dest->hasDLLExportLinkage() || 510 Dest->hasExternalWeakLinkage()) && 511 (Src->hasExternalLinkage() || 512 Src->hasDLLImportLinkage() || 513 Src->hasDLLExportLinkage() || 514 Src->hasExternalWeakLinkage()) && 515 "Unexpected linkage type!"); 516 return Error(Err, "Linking globals named '" + Src->getName() + 517 "': symbol multiply defined!"); 518 } 519 520 // Check visibility 521 if (Dest && Src->getVisibility() != Dest->getVisibility()) 522 if (!Src->isDeclaration() && !Dest->isDeclaration()) 523 return Error(Err, "Linking globals named '" + Src->getName() + 524 "': symbols have different visibilities!"); 525 return false; 526} 527 528// LinkGlobals - Loop through the global variables in the src module and merge 529// them into the dest module. 530static bool LinkGlobals(Module *Dest, const Module *Src, 531 std::map<const Value*, Value*> &ValueMap, 532 std::multimap<std::string, GlobalVariable *> &AppendingVars, 533 std::string *Err) { 534 // Loop over all of the globals in the src module, mapping them over as we go 535 for (Module::const_global_iterator I = Src->global_begin(), E = Src->global_end(); 536 I != E; ++I) { 537 const GlobalVariable *SGV = I; 538 GlobalValue *DGV = 0; 539 540 // Check to see if may have to link the global with the global 541 if (SGV->hasName() && !SGV->hasInternalLinkage()) { 542 DGV = Dest->getGlobalVariable(SGV->getName()); 543 if (DGV && DGV->getType() != SGV->getType()) 544 // If types don't agree due to opaque types, try to resolve them. 545 RecursiveResolveTypes(SGV->getType(), DGV->getType()); 546 } 547 548 // Check to see if may have to link the global with the alias 549 if (!DGV && SGV->hasName() && !SGV->hasInternalLinkage()) { 550 DGV = Dest->getNamedAlias(SGV->getName()); 551 if (DGV && DGV->getType() != SGV->getType()) 552 // If types don't agree due to opaque types, try to resolve them. 553 RecursiveResolveTypes(SGV->getType(), DGV->getType()); 554 } 555 556 if (DGV && DGV->hasInternalLinkage()) 557 DGV = 0; 558 559 assert((SGV->hasInitializer() || SGV->hasExternalWeakLinkage() || 560 SGV->hasExternalLinkage() || SGV->hasDLLImportLinkage()) && 561 "Global must either be external or have an initializer!"); 562 563 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; 564 bool LinkFromSrc = false; 565 if (GetLinkageResult(DGV, SGV, NewLinkage, LinkFromSrc, Err)) 566 return true; 567 568 if (!DGV) { 569 // No linking to be performed, simply create an identical version of the 570 // symbol over in the dest module... the initializer will be filled in 571 // later by LinkGlobalInits... 572 GlobalVariable *NewDGV = 573 new GlobalVariable(SGV->getType()->getElementType(), 574 SGV->isConstant(), SGV->getLinkage(), /*init*/0, 575 SGV->getName(), Dest); 576 // Propagate alignment, visibility and section info. 577 CopyGVAttributes(NewDGV, SGV); 578 579 // If the LLVM runtime renamed the global, but it is an externally visible 580 // symbol, DGV must be an existing global with internal linkage. Rename 581 // it. 582 if (NewDGV->getName() != SGV->getName() && !NewDGV->hasInternalLinkage()) 583 ForceRenaming(NewDGV, SGV->getName()); 584 585 // Make sure to remember this mapping... 586 ValueMap[SGV] = NewDGV; 587 588 if (SGV->hasAppendingLinkage()) 589 // Keep track that this is an appending variable... 590 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV)); 591 } else if (DGV->hasAppendingLinkage()) { 592 // No linking is performed yet. Just insert a new copy of the global, and 593 // keep track of the fact that it is an appending variable in the 594 // AppendingVars map. The name is cleared out so that no linkage is 595 // performed. 596 GlobalVariable *NewDGV = 597 new GlobalVariable(SGV->getType()->getElementType(), 598 SGV->isConstant(), SGV->getLinkage(), /*init*/0, 599 "", Dest); 600 601 // Set alignment allowing CopyGVAttributes merge it with alignment of SGV. 602 NewDGV->setAlignment(DGV->getAlignment()); 603 // Propagate alignment, section and visibility info. 604 CopyGVAttributes(NewDGV, SGV); 605 606 // Make sure to remember this mapping... 607 ValueMap[SGV] = NewDGV; 608 609 // Keep track that this is an appending variable... 610 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV)); 611 } else if (GlobalAlias *DGA = dyn_cast<GlobalAlias>(DGV)) { 612 // SGV is global, but DGV is alias. The only valid mapping is when SGV is 613 // external declaration, which is effectively a no-op. Also make sure 614 // linkage calculation was correct. 615 if (SGV->isDeclaration() && !LinkFromSrc) { 616 // Make sure to remember this mapping... 617 ValueMap[SGV] = DGA; 618 } else 619 return Error(Err, "Global-Alias Collision on '" + SGV->getName() + 620 "': symbol multiple defined"); 621 } else if (GlobalVariable *DGVar = dyn_cast<GlobalVariable>(DGV)) { 622 // Otherwise, perform the global-global mapping as instructed by 623 // GetLinkageResult. 624 if (LinkFromSrc) { 625 // Propagate alignment, section, and visibility info. 626 CopyGVAttributes(DGVar, SGV); 627 628 // If the types don't match, and if we are to link from the source, nuke 629 // DGV and create a new one of the appropriate type. 630 if (SGV->getType() != DGVar->getType()) { 631 GlobalVariable *NewDGV = 632 new GlobalVariable(SGV->getType()->getElementType(), 633 DGVar->isConstant(), DGVar->getLinkage(), 634 /*init*/0, DGVar->getName(), Dest); 635 CopyGVAttributes(NewDGV, DGVar); 636 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDGV, 637 DGVar->getType())); 638 // DGVar will conflict with NewDGV because they both had the same 639 // name. We must erase this now so ForceRenaming doesn't assert 640 // because DGV might not have internal linkage. 641 DGVar->eraseFromParent(); 642 643 // If the symbol table renamed the global, but it is an externally 644 // visible symbol, DGV must be an existing global with internal 645 // linkage. Rename it. 646 if (NewDGV->getName() != SGV->getName() && 647 !NewDGV->hasInternalLinkage()) 648 ForceRenaming(NewDGV, SGV->getName()); 649 650 DGVar = NewDGV; 651 } 652 653 // Inherit const as appropriate 654 DGVar->setConstant(SGV->isConstant()); 655 656 // Set initializer to zero, so we can link the stuff later 657 DGVar->setInitializer(0); 658 } else { 659 // Special case for const propagation 660 if (DGVar->isDeclaration() && SGV->isConstant() && !DGVar->isConstant()) 661 DGVar->setConstant(true); 662 } 663 664 // Set calculated linkage 665 DGVar->setLinkage(NewLinkage); 666 667 // Make sure to remember this mapping... 668 ValueMap[SGV] = ConstantExpr::getBitCast(DGVar, SGV->getType()); 669 } 670 } 671 return false; 672} 673 674static GlobalValue::LinkageTypes 675CalculateAliasLinkage(const GlobalValue *SGV, const GlobalValue *DGV) { 676 if (SGV->hasExternalLinkage() || DGV->hasExternalLinkage()) 677 return GlobalValue::ExternalLinkage; 678 else if (SGV->hasWeakLinkage() || DGV->hasWeakLinkage()) 679 return GlobalValue::WeakLinkage; 680 else { 681 assert(SGV->hasInternalLinkage() && DGV->hasInternalLinkage() && 682 "Unexpected linkage type"); 683 return GlobalValue::InternalLinkage; 684 } 685} 686 687// LinkAlias - Loop through the alias in the src module and link them into the 688// dest module. We're assuming, that all functions/global variables were already 689// linked in. 690static bool LinkAlias(Module *Dest, const Module *Src, 691 std::map<const Value*, Value*> &ValueMap, 692 std::string *Err) { 693 // Loop over all alias in the src module 694 for (Module::const_alias_iterator I = Src->alias_begin(), 695 E = Src->alias_end(); I != E; ++I) { 696 const GlobalAlias *SGA = I; 697 const GlobalValue *SAliasee = SGA->getAliasedGlobal(); 698 GlobalAlias *NewGA = NULL; 699 700 // Globals were already linked, thus we can just query ValueMap for variant 701 // of SAliasee in Dest. 702 std::map<const Value*,Value*>::const_iterator VMI = ValueMap.find(SAliasee); 703 assert(VMI != ValueMap.end() && "Aliasee not linked"); 704 GlobalValue* DAliasee = cast<GlobalValue>(VMI->second); 705 GlobalValue* DGV = NULL; 706 707 // Try to find something 'similar' to SGA in destination module. 708 if (!DGV && !SGA->hasInternalLinkage()) { 709 DGV = Dest->getNamedAlias(SGA->getName()); 710 711 // If types don't agree due to opaque types, try to resolve them. 712 if (DGV && DGV->getType() != SGA->getType()) 713 if (RecursiveResolveTypes(SGA->getType(), DGV->getType())) 714 return Error(Err, "Alias Collision on '" + SGA->getName()+ 715 "': aliases have different types"); 716 } 717 718 if (!DGV && !SGA->hasInternalLinkage()) { 719 DGV = Dest->getGlobalVariable(SGA->getName()); 720 721 // If types don't agree due to opaque types, try to resolve them. 722 if (DGV && DGV->getType() != SGA->getType()) 723 if (RecursiveResolveTypes(SGA->getType(), DGV->getType())) 724 return Error(Err, "Alias Collision on '" + SGA->getName()+ 725 "': aliases have different types"); 726 } 727 728 if (!DGV && !SGA->hasInternalLinkage()) { 729 DGV = Dest->getFunction(SGA->getName()); 730 731 // If types don't agree due to opaque types, try to resolve them. 732 if (DGV && DGV->getType() != SGA->getType()) 733 if (RecursiveResolveTypes(SGA->getType(), DGV->getType())) 734 return Error(Err, "Alias Collision on '" + SGA->getName()+ 735 "': aliases have different types"); 736 } 737 738 // No linking to be performed on internal stuff. 739 if (DGV && DGV->hasInternalLinkage()) 740 DGV = NULL; 741 742 if (GlobalAlias *DGA = dyn_cast_or_null<GlobalAlias>(DGV)) { 743 // Types are known to be the same, check whether aliasees equal. As 744 // globals are already linked we just need query ValueMap to find the 745 // mapping. 746 if (DAliasee == DGA->getAliasedGlobal()) { 747 // This is just two copies of the same alias. Propagate linkage, if 748 // necessary. 749 DGA->setLinkage(CalculateAliasLinkage(SGA, DGA)); 750 751 NewGA = DGA; 752 // Proceed to 'common' steps 753 } else 754 return Error(Err, "Alias Collision on '" + SGA->getName()+ 755 "': aliases have different aliasees"); 756 } else if (GlobalVariable *DGVar = dyn_cast_or_null<GlobalVariable>(DGV)) { 757 // The only allowed way is to link alias with external declaration. 758 if (DGVar->isDeclaration()) { 759 // But only if aliasee is global too... 760 if (!isa<GlobalVariable>(DAliasee)) 761 return Error(Err, "Global-Alias Collision on '" + SGA->getName() + 762 "': aliasee is not global variable"); 763 764 NewGA = new GlobalAlias(SGA->getType(), SGA->getLinkage(), 765 SGA->getName(), DAliasee, Dest); 766 CopyGVAttributes(NewGA, SGA); 767 768 // Any uses of DGV need to change to NewGA, with cast, if needed. 769 if (SGA->getType() != DGVar->getType()) 770 DGVar->replaceAllUsesWith(ConstantExpr::getBitCast(NewGA, 771 DGVar->getType())); 772 else 773 DGVar->replaceAllUsesWith(NewGA); 774 775 // DGVar will conflict with NewGA because they both had the same 776 // name. We must erase this now so ForceRenaming doesn't assert 777 // because DGV might not have internal linkage. 778 DGVar->eraseFromParent(); 779 780 // Proceed to 'common' steps 781 } else 782 return Error(Err, "Global-Alias Collision on '" + SGA->getName() + 783 "': symbol multiple defined"); 784 } else if (Function *DF = dyn_cast_or_null<Function>(DGV)) { 785 // The only allowed way is to link alias with external declaration. 786 if (DF->isDeclaration()) { 787 // But only if aliasee is function too... 788 if (!isa<Function>(DAliasee)) 789 return Error(Err, "Function-Alias Collision on '" + SGA->getName() + 790 "': aliasee is not function"); 791 792 NewGA = new GlobalAlias(SGA->getType(), SGA->getLinkage(), 793 SGA->getName(), DAliasee, Dest); 794 CopyGVAttributes(NewGA, SGA); 795 796 // Any uses of DF need to change to NewGA, with cast, if needed. 797 if (SGA->getType() != DF->getType()) 798 DF->replaceAllUsesWith(ConstantExpr::getBitCast(NewGA, 799 DF->getType())); 800 else 801 DF->replaceAllUsesWith(NewGA); 802 803 // DF will conflict with NewGA because they both had the same 804 // name. We must erase this now so ForceRenaming doesn't assert 805 // because DF might not have internal linkage. 806 DF->eraseFromParent(); 807 808 // Proceed to 'common' steps 809 } else 810 return Error(Err, "Function-Alias Collision on '" + SGA->getName() + 811 "': symbol multiple defined"); 812 } else { 813 // No linking to be performed, simply create an identical version of the 814 // alias over in the dest module... 815 816 NewGA = new GlobalAlias(SGA->getType(), SGA->getLinkage(), 817 SGA->getName(), DAliasee, Dest); 818 CopyGVAttributes(NewGA, SGA); 819 820 // Proceed to 'common' steps 821 } 822 823 assert(NewGA && "No alias was created in destination module!"); 824 825 // If the symbol table renamed the alias, but it is an externally visible 826 // symbol, DGA must be an global value with internal linkage. Rename it. 827 if (NewGA->getName() != SGA->getName() && 828 !NewGA->hasInternalLinkage()) 829 ForceRenaming(NewGA, SGA->getName()); 830 831 // Remember this mapping so uses in the source module get remapped 832 // later by RemapOperand. 833 ValueMap[SGA] = NewGA; 834 } 835 836 return false; 837} 838 839 840// LinkGlobalInits - Update the initializers in the Dest module now that all 841// globals that may be referenced are in Dest. 842static bool LinkGlobalInits(Module *Dest, const Module *Src, 843 std::map<const Value*, Value*> &ValueMap, 844 std::string *Err) { 845 846 // Loop over all of the globals in the src module, mapping them over as we go 847 for (Module::const_global_iterator I = Src->global_begin(), 848 E = Src->global_end(); I != E; ++I) { 849 const GlobalVariable *SGV = I; 850 851 if (SGV->hasInitializer()) { // Only process initialized GV's 852 // Figure out what the initializer looks like in the dest module... 853 Constant *SInit = 854 cast<Constant>(RemapOperand(SGV->getInitializer(), ValueMap)); 855 856 GlobalVariable *DGV = 857 cast<GlobalVariable>(ValueMap[SGV]->stripPointerCasts()); 858 if (DGV->hasInitializer()) { 859 if (SGV->hasExternalLinkage()) { 860 if (DGV->getInitializer() != SInit) 861 return Error(Err, "Global Variable Collision on '" + SGV->getName() + 862 "': global variables have different initializers"); 863 } else if (DGV->hasLinkOnceLinkage() || DGV->hasWeakLinkage() || 864 DGV->hasCommonLinkage()) { 865 // Nothing is required, mapped values will take the new global 866 // automatically. 867 } else if (SGV->hasLinkOnceLinkage() || SGV->hasWeakLinkage() || 868 SGV->hasCommonLinkage()) { 869 // Nothing is required, mapped values will take the new global 870 // automatically. 871 } else if (DGV->hasAppendingLinkage()) { 872 assert(0 && "Appending linkage unimplemented!"); 873 } else { 874 assert(0 && "Unknown linkage!"); 875 } 876 } else { 877 // Copy the initializer over now... 878 DGV->setInitializer(SInit); 879 } 880 } 881 } 882 return false; 883} 884 885// LinkFunctionProtos - Link the functions together between the two modules, 886// without doing function bodies... this just adds external function prototypes 887// to the Dest function... 888// 889static bool LinkFunctionProtos(Module *Dest, const Module *Src, 890 std::map<const Value*, Value*> &ValueMap, 891 std::string *Err) { 892 // Loop over all of the functions in the src module, mapping them over 893 for (Module::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) { 894 const Function *SF = I; // SrcFunction 895 896 Function *DF = 0; 897 898 // If this function is internal or has no name, it doesn't participate in 899 // linkage. 900 if (SF->hasName() && !SF->hasInternalLinkage()) { 901 // Check to see if may have to link the function. 902 DF = Dest->getFunction(SF->getName()); 903 if (DF && DF->hasInternalLinkage()) 904 DF = 0; 905 } 906 907 // If there is no linkage to be performed, just bring over SF without 908 // modifying it. 909 if (DF == 0) { 910 // Function does not already exist, simply insert an function signature 911 // identical to SF into the dest module. 912 Function *NewDF = Function::Create(SF->getFunctionType(), 913 SF->getLinkage(), 914 SF->getName(), Dest); 915 CopyGVAttributes(NewDF, SF); 916 917 // If the LLVM runtime renamed the function, but it is an externally 918 // visible symbol, DF must be an existing function with internal linkage. 919 // Rename it. 920 if (!NewDF->hasInternalLinkage() && NewDF->getName() != SF->getName()) 921 ForceRenaming(NewDF, SF->getName()); 922 923 // ... and remember this mapping... 924 ValueMap[SF] = NewDF; 925 continue; 926 } 927 928 929 // If types don't agree because of opaque, try to resolve them. 930 if (SF->getType() != DF->getType()) 931 RecursiveResolveTypes(SF->getType(), DF->getType()); 932 933 // Check visibility, merging if a definition overrides a prototype. 934 if (SF->getVisibility() != DF->getVisibility()) { 935 // If one is a prototype, ignore its visibility. Prototypes are always 936 // overridden by the definition. 937 if (!SF->isDeclaration() && !DF->isDeclaration()) 938 return Error(Err, "Linking functions named '" + SF->getName() + 939 "': symbols have different visibilities!"); 940 941 // Otherwise, replace the visibility of DF if DF is a prototype. 942 if (DF->isDeclaration()) 943 DF->setVisibility(SF->getVisibility()); 944 } 945 946 if (DF->getType() != SF->getType()) { 947 if (DF->isDeclaration() && !SF->isDeclaration()) { 948 // We have a definition of the same name but different type in the 949 // source module. Copy the prototype to the destination and replace 950 // uses of the destination's prototype with the new prototype. 951 Function *NewDF = Function::Create(SF->getFunctionType(), 952 SF->getLinkage(), 953 SF->getName(), Dest); 954 CopyGVAttributes(NewDF, SF); 955 956 // Any uses of DF need to change to NewDF, with cast 957 DF->replaceAllUsesWith(ConstantExpr::getBitCast(NewDF, DF->getType())); 958 959 // DF will conflict with NewDF because they both had the same. We must 960 // erase this now so ForceRenaming doesn't assert because DF might 961 // not have internal linkage. 962 DF->eraseFromParent(); 963 964 // If the symbol table renamed the function, but it is an externally 965 // visible symbol, DF must be an existing function with internal 966 // linkage. Rename it. 967 if (NewDF->getName() != SF->getName() && !NewDF->hasInternalLinkage()) 968 ForceRenaming(NewDF, SF->getName()); 969 970 // Remember this mapping so uses in the source module get remapped 971 // later by RemapOperand. 972 ValueMap[SF] = NewDF; 973 } else if (SF->isDeclaration()) { 974 // We have two functions of the same name but different type and the 975 // source is a declaration while the destination is not. Any use of 976 // the source must be mapped to the destination, with a cast. 977 ValueMap[SF] = ConstantExpr::getBitCast(DF, SF->getType()); 978 } else { 979 // We have two functions of the same name but different types and they 980 // are both definitions. This is an error. 981 return Error(Err, "Function '" + DF->getName() + "' defined as both '" + 982 ToStr(SF->getFunctionType(), Src) + "' and '" + 983 ToStr(DF->getFunctionType(), Dest) + "'"); 984 } 985 continue; 986 } 987 988 if (SF->isDeclaration()) { 989 // If SF is a declaration or if both SF & DF are declarations, just link 990 // the declarations, we aren't adding anything. 991 if (SF->hasDLLImportLinkage()) { 992 if (DF->isDeclaration()) { 993 ValueMap[SF] = DF; 994 DF->setLinkage(SF->getLinkage()); 995 } 996 } else { 997 ValueMap[SF] = DF; 998 } 999 continue; 1000 } 1001 1002 // If DF is external but SF is not, link the external functions, update 1003 // linkage qualifiers. 1004 if (DF->isDeclaration() && !DF->hasDLLImportLinkage()) { 1005 ValueMap.insert(std::make_pair(SF, DF)); 1006 DF->setLinkage(SF->getLinkage()); 1007 continue; 1008 } 1009 1010 // At this point we know that DF has LinkOnce, Weak, or External* linkage. 1011 if (SF->hasWeakLinkage() || SF->hasLinkOnceLinkage() || 1012 SF->hasCommonLinkage()) { 1013 ValueMap[SF] = DF; 1014 1015 // Linkonce+Weak = Weak 1016 // *+External Weak = * 1017 if ((DF->hasLinkOnceLinkage() && 1018 (SF->hasWeakLinkage() || SF->hasCommonLinkage())) || 1019 DF->hasExternalWeakLinkage()) 1020 DF->setLinkage(SF->getLinkage()); 1021 continue; 1022 } 1023 1024 if (DF->hasWeakLinkage() || DF->hasLinkOnceLinkage() || 1025 DF->hasCommonLinkage()) { 1026 // At this point we know that SF has LinkOnce or External* linkage. 1027 ValueMap[SF] = DF; 1028 1029 // If the source function has stronger linkage than the destination, 1030 // its body and linkage should override ours. 1031 if (!SF->hasLinkOnceLinkage() && !SF->hasExternalWeakLinkage()) { 1032 // Don't inherit linkonce & external weak linkage. 1033 DF->setLinkage(SF->getLinkage()); 1034 DF->deleteBody(); 1035 } 1036 continue; 1037 } 1038 1039 if (SF->getLinkage() != DF->getLinkage()) 1040 return Error(Err, "Functions named '" + SF->getName() + 1041 "' have different linkage specifiers!"); 1042 1043 // The function is defined identically in both modules! 1044 if (SF->hasExternalLinkage()) 1045 return Error(Err, "Function '" + 1046 ToStr(SF->getFunctionType(), Src) + "':\"" + 1047 SF->getName() + "\" - Function is already defined!"); 1048 assert(0 && "Unknown linkage configuration found!"); 1049 } 1050 return false; 1051} 1052 1053// LinkFunctionBody - Copy the source function over into the dest function and 1054// fix up references to values. At this point we know that Dest is an external 1055// function, and that Src is not. 1056static bool LinkFunctionBody(Function *Dest, Function *Src, 1057 std::map<const Value*, Value*> &ValueMap, 1058 std::string *Err) { 1059 assert(Src && Dest && Dest->isDeclaration() && !Src->isDeclaration()); 1060 1061 // Go through and convert function arguments over, remembering the mapping. 1062 Function::arg_iterator DI = Dest->arg_begin(); 1063 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end(); 1064 I != E; ++I, ++DI) { 1065 DI->setName(I->getName()); // Copy the name information over... 1066 1067 // Add a mapping to our local map 1068 ValueMap[I] = DI; 1069 } 1070 1071 // Splice the body of the source function into the dest function. 1072 Dest->getBasicBlockList().splice(Dest->end(), Src->getBasicBlockList()); 1073 1074 // At this point, all of the instructions and values of the function are now 1075 // copied over. The only problem is that they are still referencing values in 1076 // the Source function as operands. Loop through all of the operands of the 1077 // functions and patch them up to point to the local versions... 1078 // 1079 for (Function::iterator BB = Dest->begin(), BE = Dest->end(); BB != BE; ++BB) 1080 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) 1081 for (Instruction::op_iterator OI = I->op_begin(), OE = I->op_end(); 1082 OI != OE; ++OI) 1083 if (!isa<Instruction>(*OI) && !isa<BasicBlock>(*OI)) 1084 *OI = RemapOperand(*OI, ValueMap); 1085 1086 // There is no need to map the arguments anymore. 1087 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end(); 1088 I != E; ++I) 1089 ValueMap.erase(I); 1090 1091 return false; 1092} 1093 1094 1095// LinkFunctionBodies - Link in the function bodies that are defined in the 1096// source module into the DestModule. This consists basically of copying the 1097// function over and fixing up references to values. 1098static bool LinkFunctionBodies(Module *Dest, Module *Src, 1099 std::map<const Value*, Value*> &ValueMap, 1100 std::string *Err) { 1101 1102 // Loop over all of the functions in the src module, mapping them over as we 1103 // go 1104 for (Module::iterator SF = Src->begin(), E = Src->end(); SF != E; ++SF) { 1105 if (!SF->isDeclaration()) { // No body if function is external 1106 Function *DF = cast<Function>(ValueMap[SF]); // Destination function 1107 1108 // DF not external SF external? 1109 if (DF->isDeclaration()) 1110 // Only provide the function body if there isn't one already. 1111 if (LinkFunctionBody(DF, SF, ValueMap, Err)) 1112 return true; 1113 } 1114 } 1115 return false; 1116} 1117 1118// LinkAppendingVars - If there were any appending global variables, link them 1119// together now. Return true on error. 1120static bool LinkAppendingVars(Module *M, 1121 std::multimap<std::string, GlobalVariable *> &AppendingVars, 1122 std::string *ErrorMsg) { 1123 if (AppendingVars.empty()) return false; // Nothing to do. 1124 1125 // Loop over the multimap of appending vars, processing any variables with the 1126 // same name, forming a new appending global variable with both of the 1127 // initializers merged together, then rewrite references to the old variables 1128 // and delete them. 1129 std::vector<Constant*> Inits; 1130 while (AppendingVars.size() > 1) { 1131 // Get the first two elements in the map... 1132 std::multimap<std::string, 1133 GlobalVariable*>::iterator Second = AppendingVars.begin(), First=Second++; 1134 1135 // If the first two elements are for different names, there is no pair... 1136 // Otherwise there is a pair, so link them together... 1137 if (First->first == Second->first) { 1138 GlobalVariable *G1 = First->second, *G2 = Second->second; 1139 const ArrayType *T1 = cast<ArrayType>(G1->getType()->getElementType()); 1140 const ArrayType *T2 = cast<ArrayType>(G2->getType()->getElementType()); 1141 1142 // Check to see that they two arrays agree on type... 1143 if (T1->getElementType() != T2->getElementType()) 1144 return Error(ErrorMsg, 1145 "Appending variables with different element types need to be linked!"); 1146 if (G1->isConstant() != G2->isConstant()) 1147 return Error(ErrorMsg, 1148 "Appending variables linked with different const'ness!"); 1149 1150 if (G1->getAlignment() != G2->getAlignment()) 1151 return Error(ErrorMsg, 1152 "Appending variables with different alignment need to be linked!"); 1153 1154 if (G1->getVisibility() != G2->getVisibility()) 1155 return Error(ErrorMsg, 1156 "Appending variables with different visibility need to be linked!"); 1157 1158 if (G1->getSection() != G2->getSection()) 1159 return Error(ErrorMsg, 1160 "Appending variables with different section name need to be linked!"); 1161 1162 unsigned NewSize = T1->getNumElements() + T2->getNumElements(); 1163 ArrayType *NewType = ArrayType::get(T1->getElementType(), NewSize); 1164 1165 G1->setName(""); // Clear G1's name in case of a conflict! 1166 1167 // Create the new global variable... 1168 GlobalVariable *NG = 1169 new GlobalVariable(NewType, G1->isConstant(), G1->getLinkage(), 1170 /*init*/0, First->first, M, G1->isThreadLocal()); 1171 1172 // Propagate alignment, visibility and section info. 1173 CopyGVAttributes(NG, G1); 1174 1175 // Merge the initializer... 1176 Inits.reserve(NewSize); 1177 if (ConstantArray *I = dyn_cast<ConstantArray>(G1->getInitializer())) { 1178 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i) 1179 Inits.push_back(I->getOperand(i)); 1180 } else { 1181 assert(isa<ConstantAggregateZero>(G1->getInitializer())); 1182 Constant *CV = Constant::getNullValue(T1->getElementType()); 1183 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i) 1184 Inits.push_back(CV); 1185 } 1186 if (ConstantArray *I = dyn_cast<ConstantArray>(G2->getInitializer())) { 1187 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i) 1188 Inits.push_back(I->getOperand(i)); 1189 } else { 1190 assert(isa<ConstantAggregateZero>(G2->getInitializer())); 1191 Constant *CV = Constant::getNullValue(T2->getElementType()); 1192 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i) 1193 Inits.push_back(CV); 1194 } 1195 NG->setInitializer(ConstantArray::get(NewType, Inits)); 1196 Inits.clear(); 1197 1198 // Replace any uses of the two global variables with uses of the new 1199 // global... 1200 1201 // FIXME: This should rewrite simple/straight-forward uses such as 1202 // getelementptr instructions to not use the Cast! 1203 G1->replaceAllUsesWith(ConstantExpr::getBitCast(NG, G1->getType())); 1204 G2->replaceAllUsesWith(ConstantExpr::getBitCast(NG, G2->getType())); 1205 1206 // Remove the two globals from the module now... 1207 M->getGlobalList().erase(G1); 1208 M->getGlobalList().erase(G2); 1209 1210 // Put the new global into the AppendingVars map so that we can handle 1211 // linking of more than two vars... 1212 Second->second = NG; 1213 } 1214 AppendingVars.erase(First); 1215 } 1216 1217 return false; 1218} 1219 1220static bool ResolveAliases(Module *Dest) { 1221 for (Module::alias_iterator I = Dest->alias_begin(), E = Dest->alias_end(); 1222 I != E; ++I) 1223 if (const GlobalValue *GV = I->resolveAliasedGlobal()) 1224 if (!GV->isDeclaration()) 1225 I->replaceAllUsesWith(const_cast<GlobalValue*>(GV)); 1226 1227 return false; 1228} 1229 1230// LinkModules - This function links two modules together, with the resulting 1231// left module modified to be the composite of the two input modules. If an 1232// error occurs, true is returned and ErrorMsg (if not null) is set to indicate 1233// the problem. Upon failure, the Dest module could be in a modified state, and 1234// shouldn't be relied on to be consistent. 1235bool 1236Linker::LinkModules(Module *Dest, Module *Src, std::string *ErrorMsg) { 1237 assert(Dest != 0 && "Invalid Destination module"); 1238 assert(Src != 0 && "Invalid Source Module"); 1239 1240 if (Dest->getDataLayout().empty()) { 1241 if (!Src->getDataLayout().empty()) { 1242 Dest->setDataLayout(Src->getDataLayout()); 1243 } else { 1244 std::string DataLayout; 1245 1246 if (Dest->getEndianness() == Module::AnyEndianness) { 1247 if (Src->getEndianness() == Module::BigEndian) 1248 DataLayout.append("E"); 1249 else if (Src->getEndianness() == Module::LittleEndian) 1250 DataLayout.append("e"); 1251 } 1252 1253 if (Dest->getPointerSize() == Module::AnyPointerSize) { 1254 if (Src->getPointerSize() == Module::Pointer64) 1255 DataLayout.append(DataLayout.length() == 0 ? "p:64:64" : "-p:64:64"); 1256 else if (Src->getPointerSize() == Module::Pointer32) 1257 DataLayout.append(DataLayout.length() == 0 ? "p:32:32" : "-p:32:32"); 1258 } 1259 Dest->setDataLayout(DataLayout); 1260 } 1261 } 1262 1263 // Copy the target triple from the source to dest if the dest's is empty. 1264 if (Dest->getTargetTriple().empty() && !Src->getTargetTriple().empty()) 1265 Dest->setTargetTriple(Src->getTargetTriple()); 1266 1267 if (!Src->getDataLayout().empty() && !Dest->getDataLayout().empty() && 1268 Src->getDataLayout() != Dest->getDataLayout()) 1269 cerr << "WARNING: Linking two modules of different data layouts!\n"; 1270 if (!Src->getTargetTriple().empty() && 1271 Dest->getTargetTriple() != Src->getTargetTriple()) 1272 cerr << "WARNING: Linking two modules of different target triples!\n"; 1273 1274 // Append the module inline asm string. 1275 if (!Src->getModuleInlineAsm().empty()) { 1276 if (Dest->getModuleInlineAsm().empty()) 1277 Dest->setModuleInlineAsm(Src->getModuleInlineAsm()); 1278 else 1279 Dest->setModuleInlineAsm(Dest->getModuleInlineAsm()+"\n"+ 1280 Src->getModuleInlineAsm()); 1281 } 1282 1283 // Update the destination module's dependent libraries list with the libraries 1284 // from the source module. There's no opportunity for duplicates here as the 1285 // Module ensures that duplicate insertions are discarded. 1286 for (Module::lib_iterator SI = Src->lib_begin(), SE = Src->lib_end(); 1287 SI != SE; ++SI) 1288 Dest->addLibrary(*SI); 1289 1290 // LinkTypes - Go through the symbol table of the Src module and see if any 1291 // types are named in the src module that are not named in the Dst module. 1292 // Make sure there are no type name conflicts. 1293 if (LinkTypes(Dest, Src, ErrorMsg)) 1294 return true; 1295 1296 // ValueMap - Mapping of values from what they used to be in Src, to what they 1297 // are now in Dest. 1298 std::map<const Value*, Value*> ValueMap; 1299 1300 // AppendingVars - Keep track of global variables in the destination module 1301 // with appending linkage. After the module is linked together, they are 1302 // appended and the module is rewritten. 1303 std::multimap<std::string, GlobalVariable *> AppendingVars; 1304 for (Module::global_iterator I = Dest->global_begin(), E = Dest->global_end(); 1305 I != E; ++I) { 1306 // Add all of the appending globals already in the Dest module to 1307 // AppendingVars. 1308 if (I->hasAppendingLinkage()) 1309 AppendingVars.insert(std::make_pair(I->getName(), I)); 1310 } 1311 1312 // Insert all of the globals in src into the Dest module... without linking 1313 // initializers (which could refer to functions not yet mapped over). 1314 if (LinkGlobals(Dest, Src, ValueMap, AppendingVars, ErrorMsg)) 1315 return true; 1316 1317 // Link the functions together between the two modules, without doing function 1318 // bodies... this just adds external function prototypes to the Dest 1319 // function... We do this so that when we begin processing function bodies, 1320 // all of the global values that may be referenced are available in our 1321 // ValueMap. 1322 if (LinkFunctionProtos(Dest, Src, ValueMap, ErrorMsg)) 1323 return true; 1324 1325 // If there were any alias, link them now. We really need to do this now, 1326 // because all of the aliases that may be referenced need to be available in 1327 // ValueMap 1328 if (LinkAlias(Dest, Src, ValueMap, ErrorMsg)) return true; 1329 1330 // Update the initializers in the Dest module now that all globals that may 1331 // be referenced are in Dest. 1332 if (LinkGlobalInits(Dest, Src, ValueMap, ErrorMsg)) return true; 1333 1334 // Link in the function bodies that are defined in the source module into the 1335 // DestModule. This consists basically of copying the function over and 1336 // fixing up references to values. 1337 if (LinkFunctionBodies(Dest, Src, ValueMap, ErrorMsg)) return true; 1338 1339 // If there were any appending global variables, link them together now. 1340 if (LinkAppendingVars(Dest, AppendingVars, ErrorMsg)) return true; 1341 1342 // Resolve all uses of aliases with aliasees 1343 if (ResolveAliases(Dest)) return true; 1344 1345 // If the source library's module id is in the dependent library list of the 1346 // destination library, remove it since that module is now linked in. 1347 sys::Path modId; 1348 modId.set(Src->getModuleIdentifier()); 1349 if (!modId.isEmpty()) 1350 Dest->removeLibrary(modId.getBasename()); 1351 1352 return false; 1353} 1354 1355// vim: sw=2 1356