1 //===- Linker.cpp - Module Linker Implementation --------------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by the LLVM research group and is distributed under
6 // the University of Illinois Open Source License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements the LLVM module linker.
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
17 //===----------------------------------------------------------------------===//
19 #include "llvm/Support/Linker.h"
20 #include "llvm/Constants.h"
21 #include "llvm/DerivedTypes.h"
22 #include "llvm/Module.h"
23 #include "llvm/SymbolTable.h"
24 #include "llvm/Instructions.h"
25 #include "llvm/Assembly/Writer.h"
29 // Error - Simple wrapper function to conditionally assign to E and return true.
30 // This just makes error return conditions a little bit simpler...
32 static inline bool Error(std::string *E, const std::string &Message) {
38 // Function: ResolveTypes()
41 // Attempt to link the two specified types together.
44 // DestTy - The type to which we wish to resolve.
45 // SrcTy - The original type which we want to resolve.
46 // Name - The name of the type.
49 // DestST - The symbol table in which the new type should be placed.
52 // true - There is an error and the types cannot yet be linked.
55 static bool ResolveTypes(const Type *DestTy, const Type *SrcTy,
56 SymbolTable *DestST, const std::string &Name) {
57 if (DestTy == SrcTy) return false; // If already equal, noop
59 // Does the type already exist in the module?
60 if (DestTy && !isa<OpaqueType>(DestTy)) { // Yup, the type already exists...
61 if (const OpaqueType *OT = dyn_cast<OpaqueType>(SrcTy)) {
62 const_cast<OpaqueType*>(OT)->refineAbstractTypeTo(DestTy);
64 return true; // Cannot link types... neither is opaque and not-equal
66 } else { // Type not in dest module. Add it now.
67 if (DestTy) // Type _is_ in module, just opaque...
68 const_cast<OpaqueType*>(cast<OpaqueType>(DestTy))
69 ->refineAbstractTypeTo(SrcTy);
70 else if (!Name.empty())
71 DestST->insert(Name, const_cast<Type*>(SrcTy));
76 static const FunctionType *getFT(const PATypeHolder &TH) {
77 return cast<FunctionType>(TH.get());
79 static const StructType *getST(const PATypeHolder &TH) {
80 return cast<StructType>(TH.get());
83 // RecursiveResolveTypes - This is just like ResolveTypes, except that it
84 // recurses down into derived types, merging the used types if the parent types
87 static bool RecursiveResolveTypesI(const PATypeHolder &DestTy,
88 const PATypeHolder &SrcTy,
89 SymbolTable *DestST, const std::string &Name,
90 std::vector<std::pair<PATypeHolder, PATypeHolder> > &Pointers) {
91 const Type *SrcTyT = SrcTy.get();
92 const Type *DestTyT = DestTy.get();
93 if (DestTyT == SrcTyT) return false; // If already equal, noop
95 // If we found our opaque type, resolve it now!
96 if (isa<OpaqueType>(DestTyT) || isa<OpaqueType>(SrcTyT))
97 return ResolveTypes(DestTyT, SrcTyT, DestST, Name);
99 // Two types cannot be resolved together if they are of different primitive
100 // type. For example, we cannot resolve an int to a float.
101 if (DestTyT->getTypeID() != SrcTyT->getTypeID()) return true;
103 // Otherwise, resolve the used type used by this derived type...
104 switch (DestTyT->getTypeID()) {
105 case Type::FunctionTyID: {
106 if (cast<FunctionType>(DestTyT)->isVarArg() !=
107 cast<FunctionType>(SrcTyT)->isVarArg() ||
108 cast<FunctionType>(DestTyT)->getNumContainedTypes() !=
109 cast<FunctionType>(SrcTyT)->getNumContainedTypes())
111 for (unsigned i = 0, e = getFT(DestTy)->getNumContainedTypes(); i != e; ++i)
112 if (RecursiveResolveTypesI(getFT(DestTy)->getContainedType(i),
113 getFT(SrcTy)->getContainedType(i), DestST, "",
118 case Type::StructTyID: {
119 if (getST(DestTy)->getNumContainedTypes() !=
120 getST(SrcTy)->getNumContainedTypes()) return 1;
121 for (unsigned i = 0, e = getST(DestTy)->getNumContainedTypes(); i != e; ++i)
122 if (RecursiveResolveTypesI(getST(DestTy)->getContainedType(i),
123 getST(SrcTy)->getContainedType(i), DestST, "",
128 case Type::ArrayTyID: {
129 const ArrayType *DAT = cast<ArrayType>(DestTy.get());
130 const ArrayType *SAT = cast<ArrayType>(SrcTy.get());
131 if (DAT->getNumElements() != SAT->getNumElements()) return true;
132 return RecursiveResolveTypesI(DAT->getElementType(), SAT->getElementType(),
133 DestST, "", Pointers);
135 case Type::PointerTyID: {
136 // If this is a pointer type, check to see if we have already seen it. If
137 // so, we are in a recursive branch. Cut off the search now. We cannot use
138 // an associative container for this search, because the type pointers (keys
139 // in the container) change whenever types get resolved...
141 for (unsigned i = 0, e = Pointers.size(); i != e; ++i)
142 if (Pointers[i].first == DestTy)
143 return Pointers[i].second != SrcTy;
145 // Otherwise, add the current pointers to the vector to stop recursion on
147 Pointers.push_back(std::make_pair(DestTyT, SrcTyT));
149 RecursiveResolveTypesI(cast<PointerType>(DestTy.get())->getElementType(),
150 cast<PointerType>(SrcTy.get())->getElementType(),
151 DestST, "", Pointers);
155 default: assert(0 && "Unexpected type!"); return true;
159 static bool RecursiveResolveTypes(const PATypeHolder &DestTy,
160 const PATypeHolder &SrcTy,
161 SymbolTable *DestST, const std::string &Name){
162 std::vector<std::pair<PATypeHolder, PATypeHolder> > PointerTypes;
163 return RecursiveResolveTypesI(DestTy, SrcTy, DestST, Name, PointerTypes);
167 // LinkTypes - Go through the symbol table of the Src module and see if any
168 // types are named in the src module that are not named in the Dst module.
169 // Make sure there are no type name conflicts.
171 static bool LinkTypes(Module *Dest, const Module *Src, std::string *Err) {
172 SymbolTable *DestST = &Dest->getSymbolTable();
173 const SymbolTable *SrcST = &Src->getSymbolTable();
175 // Look for a type plane for Type's...
176 SymbolTable::type_const_iterator TI = SrcST->type_begin();
177 SymbolTable::type_const_iterator TE = SrcST->type_end();
178 if (TI == TE) return false; // No named types, do nothing.
180 // Some types cannot be resolved immediately because they depend on other
181 // types being resolved to each other first. This contains a list of types we
182 // are waiting to recheck.
183 std::vector<std::string> DelayedTypesToResolve;
185 for ( ; TI != TE; ++TI ) {
186 const std::string &Name = TI->first;
187 const Type *RHS = TI->second;
189 // Check to see if this type name is already in the dest module...
190 Type *Entry = DestST->lookupType(Name);
192 if (ResolveTypes(Entry, RHS, DestST, Name)) {
193 // They look different, save the types 'till later to resolve.
194 DelayedTypesToResolve.push_back(Name);
198 // Iteratively resolve types while we can...
199 while (!DelayedTypesToResolve.empty()) {
200 // Loop over all of the types, attempting to resolve them if possible...
201 unsigned OldSize = DelayedTypesToResolve.size();
203 // Try direct resolution by name...
204 for (unsigned i = 0; i != DelayedTypesToResolve.size(); ++i) {
205 const std::string &Name = DelayedTypesToResolve[i];
206 Type *T1 = SrcST->lookupType(Name);
207 Type *T2 = DestST->lookupType(Name);
208 if (!ResolveTypes(T2, T1, DestST, Name)) {
209 // We are making progress!
210 DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i);
215 // Did we not eliminate any types?
216 if (DelayedTypesToResolve.size() == OldSize) {
217 // Attempt to resolve subelements of types. This allows us to merge these
218 // two types: { int* } and { opaque* }
219 for (unsigned i = 0, e = DelayedTypesToResolve.size(); i != e; ++i) {
220 const std::string &Name = DelayedTypesToResolve[i];
221 PATypeHolder T1(SrcST->lookupType(Name));
222 PATypeHolder T2(DestST->lookupType(Name));
224 if (!RecursiveResolveTypes(T2, T1, DestST, Name)) {
225 // We are making progress!
226 DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i);
228 // Go back to the main loop, perhaps we can resolve directly by name
234 // If we STILL cannot resolve the types, then there is something wrong.
235 // Report the warning and delete one of the names.
236 if (DelayedTypesToResolve.size() == OldSize) {
237 const std::string &Name = DelayedTypesToResolve.back();
239 const Type *T1 = SrcST->lookupType(Name);
240 const Type *T2 = DestST->lookupType(Name);
241 std::cerr << "WARNING: Type conflict between types named '" << Name
243 WriteTypeSymbolic(std::cerr, T1, Src);
244 std::cerr << "'.\n Dest='";
245 WriteTypeSymbolic(std::cerr, T2, Dest);
248 // Remove the symbol name from the destination.
249 DelayedTypesToResolve.pop_back();
258 static void PrintMap(const std::map<const Value*, Value*> &M) {
259 for (std::map<const Value*, Value*>::const_iterator I = M.begin(), E =M.end();
261 std::cerr << " Fr: " << (void*)I->first << " ";
263 std::cerr << " To: " << (void*)I->second << " ";
270 // RemapOperand - Use LocalMap and GlobalMap to convert references from one
271 // module to another. This is somewhat sophisticated in that it can
272 // automatically handle constant references correctly as well...
274 static Value *RemapOperand(const Value *In,
275 std::map<const Value*, Value*> &LocalMap,
276 std::map<const Value*, Value*> *GlobalMap) {
277 std::map<const Value*,Value*>::const_iterator I = LocalMap.find(In);
278 if (I != LocalMap.end()) return I->second;
281 I = GlobalMap->find(In);
282 if (I != GlobalMap->end()) return I->second;
285 // Check to see if it's a constant that we are interesting in transforming...
286 if (const Constant *CPV = dyn_cast<Constant>(In)) {
287 if ((!isa<DerivedType>(CPV->getType()) && !isa<ConstantExpr>(CPV)) ||
288 isa<ConstantAggregateZero>(CPV))
289 return const_cast<Constant*>(CPV); // Simple constants stay identical...
291 Constant *Result = 0;
293 if (const ConstantArray *CPA = dyn_cast<ConstantArray>(CPV)) {
294 std::vector<Constant*> Operands(CPA->getNumOperands());
295 for (unsigned i = 0, e = CPA->getNumOperands(); i != e; ++i)
297 cast<Constant>(RemapOperand(CPA->getOperand(i), LocalMap, GlobalMap));
298 Result = ConstantArray::get(cast<ArrayType>(CPA->getType()), Operands);
299 } else if (const ConstantStruct *CPS = dyn_cast<ConstantStruct>(CPV)) {
300 std::vector<Constant*> Operands(CPS->getNumOperands());
301 for (unsigned i = 0, e = CPS->getNumOperands(); i != e; ++i)
303 cast<Constant>(RemapOperand(CPS->getOperand(i), LocalMap, GlobalMap));
304 Result = ConstantStruct::get(cast<StructType>(CPS->getType()), Operands);
305 } else if (isa<ConstantPointerNull>(CPV)) {
306 Result = const_cast<Constant*>(CPV);
307 } else if (isa<GlobalValue>(CPV)) {
308 Result = cast<Constant>(RemapOperand(CPV, LocalMap, GlobalMap));
309 } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CPV)) {
310 if (CE->getOpcode() == Instruction::GetElementPtr) {
311 Value *Ptr = RemapOperand(CE->getOperand(0), LocalMap, GlobalMap);
312 std::vector<Constant*> Indices;
313 Indices.reserve(CE->getNumOperands()-1);
314 for (unsigned i = 1, e = CE->getNumOperands(); i != e; ++i)
315 Indices.push_back(cast<Constant>(RemapOperand(CE->getOperand(i),
316 LocalMap, GlobalMap)));
318 Result = ConstantExpr::getGetElementPtr(cast<Constant>(Ptr), Indices);
319 } else if (CE->getNumOperands() == 1) {
321 assert(CE->getOpcode() == Instruction::Cast);
322 Value *V = RemapOperand(CE->getOperand(0), LocalMap, GlobalMap);
323 Result = ConstantExpr::getCast(cast<Constant>(V), CE->getType());
324 } else if (CE->getNumOperands() == 3) {
325 // Select instruction
326 assert(CE->getOpcode() == Instruction::Select);
327 Value *V1 = RemapOperand(CE->getOperand(0), LocalMap, GlobalMap);
328 Value *V2 = RemapOperand(CE->getOperand(1), LocalMap, GlobalMap);
329 Value *V3 = RemapOperand(CE->getOperand(2), LocalMap, GlobalMap);
330 Result = ConstantExpr::getSelect(cast<Constant>(V1), cast<Constant>(V2),
332 } else if (CE->getNumOperands() == 2) {
333 // Binary operator...
334 Value *V1 = RemapOperand(CE->getOperand(0), LocalMap, GlobalMap);
335 Value *V2 = RemapOperand(CE->getOperand(1), LocalMap, GlobalMap);
337 Result = ConstantExpr::get(CE->getOpcode(), cast<Constant>(V1),
340 assert(0 && "Unknown constant expr type!");
344 assert(0 && "Unknown type of derived type constant value!");
347 // Cache the mapping in our local map structure...
349 GlobalMap->insert(std::make_pair(In, Result));
351 LocalMap.insert(std::make_pair(In, Result));
355 std::cerr << "XXX LocalMap: \n";
359 std::cerr << "XXX GlobalMap: \n";
360 PrintMap(*GlobalMap);
363 std::cerr << "Couldn't remap value: " << (void*)In << " " << *In << "\n";
364 assert(0 && "Couldn't remap value!");
368 /// ForceRenaming - The LLVM SymbolTable class autorenames globals that conflict
369 /// in the symbol table. This is good for all clients except for us. Go
370 /// through the trouble to force this back.
371 static void ForceRenaming(GlobalValue *GV, const std::string &Name) {
372 assert(GV->getName() != Name && "Can't force rename to self");
373 SymbolTable &ST = GV->getParent()->getSymbolTable();
375 // If there is a conflict, rename the conflict.
376 Value *ConflictVal = ST.lookup(GV->getType(), Name);
377 assert(ConflictVal&&"Why do we have to force rename if there is no conflic?");
378 GlobalValue *ConflictGV = cast<GlobalValue>(ConflictVal);
379 assert(ConflictGV->hasInternalLinkage() &&
380 "Not conflicting with a static global, should link instead!");
382 ConflictGV->setName(""); // Eliminate the conflict
383 GV->setName(Name); // Force the name back
384 ConflictGV->setName(Name); // This will cause ConflictGV to get renamed
385 assert(GV->getName() == Name && ConflictGV->getName() != Name &&
386 "ForceRenaming didn't work");
390 // LinkGlobals - Loop through the global variables in the src module and merge
391 // them into the dest module.
393 static bool LinkGlobals(Module *Dest, const Module *Src,
394 std::map<const Value*, Value*> &ValueMap,
395 std::multimap<std::string, GlobalVariable *> &AppendingVars,
396 std::map<std::string, GlobalValue*> &GlobalsByName,
398 // We will need a module level symbol table if the src module has a module
399 // level symbol table...
400 SymbolTable *ST = (SymbolTable*)&Dest->getSymbolTable();
402 // Loop over all of the globals in the src module, mapping them over as we go
404 for (Module::const_giterator I = Src->gbegin(), E = Src->gend(); I != E; ++I){
405 const GlobalVariable *SGV = I;
406 GlobalVariable *DGV = 0;
407 // Check to see if may have to link the global.
408 if (SGV->hasName() && !SGV->hasInternalLinkage())
409 if (!(DGV = Dest->getGlobalVariable(SGV->getName(),
410 SGV->getType()->getElementType()))) {
411 std::map<std::string, GlobalValue*>::iterator EGV =
412 GlobalsByName.find(SGV->getName());
413 if (EGV != GlobalsByName.end())
414 DGV = dyn_cast<GlobalVariable>(EGV->second);
415 if (DGV && RecursiveResolveTypes(SGV->getType(), DGV->getType(), ST, ""))
416 DGV = 0; // FIXME: gross.
419 assert(SGV->hasInitializer() || SGV->hasExternalLinkage() &&
420 "Global must either be external or have an initializer!");
422 bool SGExtern = SGV->isExternal();
423 bool DGExtern = DGV ? DGV->isExternal() : false;
425 if (!DGV || DGV->hasInternalLinkage() || SGV->hasInternalLinkage()) {
426 // No linking to be performed, simply create an identical version of the
427 // symbol over in the dest module... the initializer will be filled in
428 // later by LinkGlobalInits...
430 GlobalVariable *NewDGV =
431 new GlobalVariable(SGV->getType()->getElementType(),
432 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
433 SGV->getName(), Dest);
435 // If the LLVM runtime renamed the global, but it is an externally visible
436 // symbol, DGV must be an existing global with internal linkage. Rename
438 if (NewDGV->getName() != SGV->getName() && !NewDGV->hasInternalLinkage())
439 ForceRenaming(NewDGV, SGV->getName());
441 // Make sure to remember this mapping...
442 ValueMap.insert(std::make_pair(SGV, NewDGV));
443 if (SGV->hasAppendingLinkage())
444 // Keep track that this is an appending variable...
445 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV));
447 } else if (SGV->isExternal()) {
448 // If SGV is external or if both SGV & DGV are external.. Just link the
449 // external globals, we aren't adding anything.
450 ValueMap.insert(std::make_pair(SGV, DGV));
452 } else if (DGV->isExternal()) { // If DGV is external but SGV is not...
453 ValueMap.insert(std::make_pair(SGV, DGV));
454 DGV->setLinkage(SGV->getLinkage()); // Inherit linkage!
455 } else if (SGV->hasWeakLinkage() || SGV->hasLinkOnceLinkage()) {
456 // At this point we know that DGV has LinkOnce, Appending, Weak, or
457 // External linkage. If DGV is Appending, this is an error.
458 if (DGV->hasAppendingLinkage())
459 return Error(Err, "Linking globals named '" + SGV->getName() +
460 " ' with 'weak' and 'appending' linkage is not allowed!");
462 if (SGV->isConstant() != DGV->isConstant())
463 return Error(Err, "Global Variable Collision on '" +
464 SGV->getType()->getDescription() + " %" + SGV->getName() +
465 "' - Global variables differ in const'ness");
467 // Otherwise, just perform the link.
468 ValueMap.insert(std::make_pair(SGV, DGV));
470 // Linkonce+Weak = Weak
471 if (DGV->hasLinkOnceLinkage() && SGV->hasWeakLinkage())
472 DGV->setLinkage(SGV->getLinkage());
474 } else if (DGV->hasWeakLinkage() || DGV->hasLinkOnceLinkage()) {
475 // At this point we know that SGV has LinkOnce, Appending, or External
476 // linkage. If SGV is Appending, this is an error.
477 if (SGV->hasAppendingLinkage())
478 return Error(Err, "Linking globals named '" + SGV->getName() +
479 " ' with 'weak' and 'appending' linkage is not allowed!");
481 if (SGV->isConstant() != DGV->isConstant())
482 return Error(Err, "Global Variable Collision on '" +
483 SGV->getType()->getDescription() + " %" + SGV->getName() +
484 "' - Global variables differ in const'ness");
486 if (!SGV->hasLinkOnceLinkage())
487 DGV->setLinkage(SGV->getLinkage()); // Inherit linkage!
488 ValueMap.insert(std::make_pair(SGV, DGV));
490 } else if (SGV->getLinkage() != DGV->getLinkage()) {
491 return Error(Err, "Global variables named '" + SGV->getName() +
492 "' have different linkage specifiers!");
493 } else if (SGV->hasExternalLinkage()) {
494 // Allow linking two exactly identical external global variables...
495 if (SGV->isConstant() != DGV->isConstant())
496 return Error(Err, "Global Variable Collision on '" +
497 SGV->getType()->getDescription() + " %" + SGV->getName() +
498 "' - Global variables differ in const'ness");
500 if (SGV->getInitializer() != DGV->getInitializer())
501 return Error(Err, "Global Variable Collision on '" +
502 SGV->getType()->getDescription() + " %" + SGV->getName() +
503 "' - External linkage globals have different initializers");
505 ValueMap.insert(std::make_pair(SGV, DGV));
506 } else if (SGV->hasAppendingLinkage()) {
507 // No linking is performed yet. Just insert a new copy of the global, and
508 // keep track of the fact that it is an appending variable in the
509 // AppendingVars map. The name is cleared out so that no linkage is
511 GlobalVariable *NewDGV =
512 new GlobalVariable(SGV->getType()->getElementType(),
513 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
516 // Make sure to remember this mapping...
517 ValueMap.insert(std::make_pair(SGV, NewDGV));
519 // Keep track that this is an appending variable...
520 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV));
522 assert(0 && "Unknown linkage!");
529 // LinkGlobalInits - Update the initializers in the Dest module now that all
530 // globals that may be referenced are in Dest.
532 static bool LinkGlobalInits(Module *Dest, const Module *Src,
533 std::map<const Value*, Value*> &ValueMap,
536 // Loop over all of the globals in the src module, mapping them over as we go
538 for (Module::const_giterator I = Src->gbegin(), E = Src->gend(); I != E; ++I){
539 const GlobalVariable *SGV = I;
541 if (SGV->hasInitializer()) { // Only process initialized GV's
542 // Figure out what the initializer looks like in the dest module...
544 cast<Constant>(RemapOperand(SGV->getInitializer(), ValueMap, 0));
546 GlobalVariable *DGV = cast<GlobalVariable>(ValueMap[SGV]);
547 if (DGV->hasInitializer()) {
548 if (SGV->hasExternalLinkage()) {
549 if (DGV->getInitializer() != SInit)
550 return Error(Err, "Global Variable Collision on '" +
551 SGV->getType()->getDescription() +"':%"+SGV->getName()+
552 " - Global variables have different initializers");
553 } else if (DGV->hasLinkOnceLinkage() || DGV->hasWeakLinkage()) {
554 // Nothing is required, mapped values will take the new global
556 } else if (SGV->hasLinkOnceLinkage() || SGV->hasWeakLinkage()) {
557 // Nothing is required, mapped values will take the new global
559 } else if (DGV->hasAppendingLinkage()) {
560 assert(0 && "Appending linkage unimplemented!");
562 assert(0 && "Unknown linkage!");
565 // Copy the initializer over now...
566 DGV->setInitializer(SInit);
573 // LinkFunctionProtos - Link the functions together between the two modules,
574 // without doing function bodies... this just adds external function prototypes
575 // to the Dest function...
577 static bool LinkFunctionProtos(Module *Dest, const Module *Src,
578 std::map<const Value*, Value*> &ValueMap,
579 std::map<std::string, GlobalValue*> &GlobalsByName,
581 SymbolTable *ST = (SymbolTable*)&Dest->getSymbolTable();
583 // Loop over all of the functions in the src module, mapping them over as we
586 for (Module::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) {
587 const Function *SF = I; // SrcFunction
589 if (SF->hasName() && !SF->hasInternalLinkage()) {
590 // Check to see if may have to link the function.
591 if (!(DF = Dest->getFunction(SF->getName(), SF->getFunctionType()))) {
592 std::map<std::string, GlobalValue*>::iterator EF =
593 GlobalsByName.find(SF->getName());
594 if (EF != GlobalsByName.end())
595 DF = dyn_cast<Function>(EF->second);
596 if (DF && RecursiveResolveTypes(SF->getType(), DF->getType(), ST, ""))
597 DF = 0; // FIXME: gross.
601 if (!DF || SF->hasInternalLinkage() || DF->hasInternalLinkage()) {
602 // Function does not already exist, simply insert an function signature
603 // identical to SF into the dest module...
604 Function *NewDF = new Function(SF->getFunctionType(), SF->getLinkage(),
605 SF->getName(), Dest);
607 // If the LLVM runtime renamed the function, but it is an externally
608 // visible symbol, DF must be an existing function with internal linkage.
610 if (NewDF->getName() != SF->getName() && !NewDF->hasInternalLinkage())
611 ForceRenaming(NewDF, SF->getName());
613 // ... and remember this mapping...
614 ValueMap.insert(std::make_pair(SF, NewDF));
615 } else if (SF->isExternal()) {
616 // If SF is external or if both SF & DF are external.. Just link the
617 // external functions, we aren't adding anything.
618 ValueMap.insert(std::make_pair(SF, DF));
619 } else if (DF->isExternal()) { // If DF is external but SF is not...
620 // Link the external functions, update linkage qualifiers
621 ValueMap.insert(std::make_pair(SF, DF));
622 DF->setLinkage(SF->getLinkage());
624 } else if (SF->hasWeakLinkage() || SF->hasLinkOnceLinkage()) {
625 // At this point we know that DF has LinkOnce, Weak, or External linkage.
626 ValueMap.insert(std::make_pair(SF, DF));
628 // Linkonce+Weak = Weak
629 if (DF->hasLinkOnceLinkage() && SF->hasWeakLinkage())
630 DF->setLinkage(SF->getLinkage());
632 } else if (DF->hasWeakLinkage() || DF->hasLinkOnceLinkage()) {
633 // At this point we know that SF has LinkOnce or External linkage.
634 ValueMap.insert(std::make_pair(SF, DF));
635 if (!SF->hasLinkOnceLinkage()) // Don't inherit linkonce linkage
636 DF->setLinkage(SF->getLinkage());
638 } else if (SF->getLinkage() != DF->getLinkage()) {
639 return Error(Err, "Functions named '" + SF->getName() +
640 "' have different linkage specifiers!");
641 } else if (SF->hasExternalLinkage()) {
642 // The function is defined in both modules!!
643 return Error(Err, "Function '" +
644 SF->getFunctionType()->getDescription() + "':\"" +
645 SF->getName() + "\" - Function is already defined!");
647 assert(0 && "Unknown linkage configuration found!");
653 // LinkFunctionBody - Copy the source function over into the dest function and
654 // fix up references to values. At this point we know that Dest is an external
655 // function, and that Src is not.
657 static bool LinkFunctionBody(Function *Dest, const Function *Src,
658 std::map<const Value*, Value*> &GlobalMap,
660 assert(Src && Dest && Dest->isExternal() && !Src->isExternal());
661 std::map<const Value*, Value*> LocalMap; // Map for function local values
663 // Go through and convert function arguments over...
664 Function::aiterator DI = Dest->abegin();
665 for (Function::const_aiterator I = Src->abegin(), E = Src->aend();
667 DI->setName(I->getName()); // Copy the name information over...
669 // Add a mapping to our local map
670 LocalMap.insert(std::make_pair(I, DI));
673 // Loop over all of the basic blocks, copying the instructions over...
675 for (Function::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) {
676 // Create new basic block and add to mapping and the Dest function...
677 BasicBlock *DBB = new BasicBlock(I->getName(), Dest);
678 LocalMap.insert(std::make_pair(I, DBB));
680 // Loop over all of the instructions in the src basic block, copying them
681 // over. Note that this is broken in a strict sense because the cloned
682 // instructions will still be referencing values in the Src module, not
683 // the remapped values. In our case, however, we will not get caught and
684 // so we can delay patching the values up until later...
686 for (BasicBlock::const_iterator II = I->begin(), IE = I->end();
688 Instruction *DI = II->clone();
689 DI->setName(II->getName());
690 DBB->getInstList().push_back(DI);
691 LocalMap.insert(std::make_pair(II, DI));
695 // At this point, all of the instructions and values of the function are now
696 // copied over. The only problem is that they are still referencing values in
697 // the Source function as operands. Loop through all of the operands of the
698 // functions and patch them up to point to the local versions...
700 for (Function::iterator BB = Dest->begin(), BE = Dest->end(); BB != BE; ++BB)
701 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
702 for (Instruction::op_iterator OI = I->op_begin(), OE = I->op_end();
704 *OI = RemapOperand(*OI, LocalMap, &GlobalMap);
710 // LinkFunctionBodies - Link in the function bodies that are defined in the
711 // source module into the DestModule. This consists basically of copying the
712 // function over and fixing up references to values.
714 static bool LinkFunctionBodies(Module *Dest, const Module *Src,
715 std::map<const Value*, Value*> &ValueMap,
718 // Loop over all of the functions in the src module, mapping them over as we
721 for (Module::const_iterator SF = Src->begin(), E = Src->end(); SF != E; ++SF){
722 if (!SF->isExternal()) { // No body if function is external
723 Function *DF = cast<Function>(ValueMap[SF]); // Destination function
725 // DF not external SF external?
726 if (DF->isExternal()) {
727 // Only provide the function body if there isn't one already.
728 if (LinkFunctionBody(DF, SF, ValueMap, Err))
736 // LinkAppendingVars - If there were any appending global variables, link them
737 // together now. Return true on error.
739 static bool LinkAppendingVars(Module *M,
740 std::multimap<std::string, GlobalVariable *> &AppendingVars,
741 std::string *ErrorMsg) {
742 if (AppendingVars.empty()) return false; // Nothing to do.
744 // Loop over the multimap of appending vars, processing any variables with the
745 // same name, forming a new appending global variable with both of the
746 // initializers merged together, then rewrite references to the old variables
749 std::vector<Constant*> Inits;
750 while (AppendingVars.size() > 1) {
751 // Get the first two elements in the map...
752 std::multimap<std::string,
753 GlobalVariable*>::iterator Second = AppendingVars.begin(), First=Second++;
755 // If the first two elements are for different names, there is no pair...
756 // Otherwise there is a pair, so link them together...
757 if (First->first == Second->first) {
758 GlobalVariable *G1 = First->second, *G2 = Second->second;
759 const ArrayType *T1 = cast<ArrayType>(G1->getType()->getElementType());
760 const ArrayType *T2 = cast<ArrayType>(G2->getType()->getElementType());
762 // Check to see that they two arrays agree on type...
763 if (T1->getElementType() != T2->getElementType())
764 return Error(ErrorMsg,
765 "Appending variables with different element types need to be linked!");
766 if (G1->isConstant() != G2->isConstant())
767 return Error(ErrorMsg,
768 "Appending variables linked with different const'ness!");
770 unsigned NewSize = T1->getNumElements() + T2->getNumElements();
771 ArrayType *NewType = ArrayType::get(T1->getElementType(), NewSize);
773 // Create the new global variable...
775 new GlobalVariable(NewType, G1->isConstant(), G1->getLinkage(),
776 /*init*/0, First->first, M);
778 // Merge the initializer...
779 Inits.reserve(NewSize);
780 if (ConstantArray *I = dyn_cast<ConstantArray>(G1->getInitializer())) {
781 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i)
782 Inits.push_back(I->getOperand(i));
784 assert(isa<ConstantAggregateZero>(G1->getInitializer()));
785 Constant *CV = Constant::getNullValue(T1->getElementType());
786 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i)
789 if (ConstantArray *I = dyn_cast<ConstantArray>(G2->getInitializer())) {
790 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i)
791 Inits.push_back(I->getOperand(i));
793 assert(isa<ConstantAggregateZero>(G2->getInitializer()));
794 Constant *CV = Constant::getNullValue(T2->getElementType());
795 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i)
798 NG->setInitializer(ConstantArray::get(NewType, Inits));
801 // Replace any uses of the two global variables with uses of the new
804 // FIXME: This should rewrite simple/straight-forward uses such as
805 // getelementptr instructions to not use the Cast!
806 G1->replaceAllUsesWith(ConstantExpr::getCast(NG, G1->getType()));
807 G2->replaceAllUsesWith(ConstantExpr::getCast(NG, G2->getType()));
809 // Remove the two globals from the module now...
810 M->getGlobalList().erase(G1);
811 M->getGlobalList().erase(G2);
813 // Put the new global into the AppendingVars map so that we can handle
814 // linking of more than two vars...
817 AppendingVars.erase(First);
824 // LinkModules - This function links two modules together, with the resulting
825 // left module modified to be the composite of the two input modules. If an
826 // error occurs, true is returned and ErrorMsg (if not null) is set to indicate
827 // the problem. Upon failure, the Dest module could be in a modified state, and
828 // shouldn't be relied on to be consistent.
830 bool llvm::LinkModules(Module *Dest, const Module *Src, std::string *ErrorMsg) {
831 if (Dest->getEndianness() == Module::AnyEndianness)
832 Dest->setEndianness(Src->getEndianness());
833 if (Dest->getPointerSize() == Module::AnyPointerSize)
834 Dest->setPointerSize(Src->getPointerSize());
836 if (Src->getEndianness() != Module::AnyEndianness &&
837 Dest->getEndianness() != Src->getEndianness())
838 std::cerr << "WARNING: Linking two modules of different endianness!\n";
839 if (Src->getPointerSize() != Module::AnyPointerSize &&
840 Dest->getPointerSize() != Src->getPointerSize())
841 std::cerr << "WARNING: Linking two modules of different pointer size!\n";
843 // LinkTypes - Go through the symbol table of the Src module and see if any
844 // types are named in the src module that are not named in the Dst module.
845 // Make sure there are no type name conflicts.
847 if (LinkTypes(Dest, Src, ErrorMsg)) return true;
849 // ValueMap - Mapping of values from what they used to be in Src, to what they
852 std::map<const Value*, Value*> ValueMap;
854 // AppendingVars - Keep track of global variables in the destination module
855 // with appending linkage. After the module is linked together, they are
856 // appended and the module is rewritten.
858 std::multimap<std::string, GlobalVariable *> AppendingVars;
860 // GlobalsByName - The LLVM SymbolTable class fights our best efforts at
861 // linking by separating globals by type. Until PR411 is fixed, we replicate
862 // it's functionality here.
863 std::map<std::string, GlobalValue*> GlobalsByName;
865 for (Module::giterator I = Dest->gbegin(), E = Dest->gend(); I != E; ++I) {
866 // Add all of the appending globals already in the Dest module to
868 if (I->hasAppendingLinkage())
869 AppendingVars.insert(std::make_pair(I->getName(), I));
871 // Keep track of all globals by name.
872 if (!I->hasInternalLinkage() && I->hasName())
873 GlobalsByName[I->getName()] = I;
876 // Keep track of all globals by name.
877 for (Module::iterator I = Dest->begin(), E = Dest->end(); I != E; ++I)
878 if (!I->hasInternalLinkage() && I->hasName())
879 GlobalsByName[I->getName()] = I;
881 // Insert all of the globals in src into the Dest module... without linking
882 // initializers (which could refer to functions not yet mapped over).
884 if (LinkGlobals(Dest, Src, ValueMap, AppendingVars, GlobalsByName, ErrorMsg))
887 // Link the functions together between the two modules, without doing function
888 // bodies... this just adds external function prototypes to the Dest
889 // function... We do this so that when we begin processing function bodies,
890 // all of the global values that may be referenced are available in our
893 if (LinkFunctionProtos(Dest, Src, ValueMap, GlobalsByName, ErrorMsg))
896 // Update the initializers in the Dest module now that all globals that may
897 // be referenced are in Dest.
899 if (LinkGlobalInits(Dest, Src, ValueMap, ErrorMsg)) return true;
901 // Link in the function bodies that are defined in the source module into the
902 // DestModule. This consists basically of copying the function over and
903 // fixing up references to values.
905 if (LinkFunctionBodies(Dest, Src, ValueMap, ErrorMsg)) return true;
907 // If there were any appending global variables, link them together now.
909 if (LinkAppendingVars(Dest, AppendingVars, ErrorMsg)) return true;