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/Transforms/Utils/Linker.h"
20 #include "llvm/Module.h"
21 #include "llvm/SymbolTable.h"
22 #include "llvm/DerivedTypes.h"
23 #include "llvm/iOther.h"
24 #include "llvm/Constants.h"
26 // Error - Simple wrapper function to conditionally assign to E and return true.
27 // This just makes error return conditions a little bit simpler...
29 static inline bool Error(std::string *E, const std::string &Message) {
34 // ResolveTypes - Attempt to link the two specified types together. Return true
35 // if there is an error and they cannot yet be linked.
37 static bool ResolveTypes(const Type *DestTy, const Type *SrcTy,
38 SymbolTable *DestST, const std::string &Name) {
39 if (DestTy == SrcTy) return false; // If already equal, noop
41 // Does the type already exist in the module?
42 if (DestTy && !isa<OpaqueType>(DestTy)) { // Yup, the type already exists...
43 if (const OpaqueType *OT = dyn_cast<OpaqueType>(SrcTy)) {
44 const_cast<OpaqueType*>(OT)->refineAbstractTypeTo(DestTy);
46 return true; // Cannot link types... neither is opaque and not-equal
48 } else { // Type not in dest module. Add it now.
49 if (DestTy) // Type _is_ in module, just opaque...
50 const_cast<OpaqueType*>(cast<OpaqueType>(DestTy))
51 ->refineAbstractTypeTo(SrcTy);
52 else if (!Name.empty())
53 DestST->insert(Name, const_cast<Type*>(SrcTy));
58 static const FunctionType *getFT(const PATypeHolder &TH) {
59 return cast<FunctionType>(TH.get());
61 static const StructType *getST(const PATypeHolder &TH) {
62 return cast<StructType>(TH.get());
65 // RecursiveResolveTypes - This is just like ResolveTypes, except that it
66 // recurses down into derived types, merging the used types if the parent types
69 static bool RecursiveResolveTypesI(const PATypeHolder &DestTy,
70 const PATypeHolder &SrcTy,
71 SymbolTable *DestST, const std::string &Name,
72 std::vector<std::pair<PATypeHolder, PATypeHolder> > &Pointers) {
73 const Type *SrcTyT = SrcTy.get();
74 const Type *DestTyT = DestTy.get();
75 if (DestTyT == SrcTyT) return false; // If already equal, noop
77 // If we found our opaque type, resolve it now!
78 if (isa<OpaqueType>(DestTyT) || isa<OpaqueType>(SrcTyT))
79 return ResolveTypes(DestTyT, SrcTyT, DestST, Name);
81 // Two types cannot be resolved together if they are of different primitive
82 // type. For example, we cannot resolve an int to a float.
83 if (DestTyT->getPrimitiveID() != SrcTyT->getPrimitiveID()) return true;
85 // Otherwise, resolve the used type used by this derived type...
86 switch (DestTyT->getPrimitiveID()) {
87 case Type::FunctionTyID: {
88 if (cast<FunctionType>(DestTyT)->isVarArg() !=
89 cast<FunctionType>(SrcTyT)->isVarArg() ||
90 cast<FunctionType>(DestTyT)->getNumContainedTypes() !=
91 cast<FunctionType>(SrcTyT)->getNumContainedTypes())
93 for (unsigned i = 0, e = getFT(DestTy)->getNumContainedTypes(); i != e; ++i)
94 if (RecursiveResolveTypesI(getFT(DestTy)->getContainedType(i),
95 getFT(SrcTy)->getContainedType(i), DestST, "",
100 case Type::StructTyID: {
101 if (getST(DestTy)->getNumContainedTypes() !=
102 getST(SrcTy)->getNumContainedTypes()) return 1;
103 for (unsigned i = 0, e = getST(DestTy)->getNumContainedTypes(); i != e; ++i)
104 if (RecursiveResolveTypesI(getST(DestTy)->getContainedType(i),
105 getST(SrcTy)->getContainedType(i), DestST, "",
110 case Type::ArrayTyID: {
111 const ArrayType *DAT = cast<ArrayType>(DestTy.get());
112 const ArrayType *SAT = cast<ArrayType>(SrcTy.get());
113 if (DAT->getNumElements() != SAT->getNumElements()) return true;
114 return RecursiveResolveTypesI(DAT->getElementType(), SAT->getElementType(),
115 DestST, "", Pointers);
117 case Type::PointerTyID: {
118 // If this is a pointer type, check to see if we have already seen it. If
119 // so, we are in a recursive branch. Cut off the search now. We cannot use
120 // an associative container for this search, because the type pointers (keys
121 // in the container) change whenever types get resolved...
123 for (unsigned i = 0, e = Pointers.size(); i != e; ++i)
124 if (Pointers[i].first == DestTy)
125 return Pointers[i].second != SrcTy;
127 // Otherwise, add the current pointers to the vector to stop recursion on
129 Pointers.push_back(std::make_pair(DestTyT, SrcTyT));
131 RecursiveResolveTypesI(cast<PointerType>(DestTy.get())->getElementType(),
132 cast<PointerType>(SrcTy.get())->getElementType(),
133 DestST, "", Pointers);
137 default: assert(0 && "Unexpected type!"); return true;
141 static bool RecursiveResolveTypes(const PATypeHolder &DestTy,
142 const PATypeHolder &SrcTy,
143 SymbolTable *DestST, const std::string &Name){
144 std::vector<std::pair<PATypeHolder, PATypeHolder> > PointerTypes;
145 return RecursiveResolveTypesI(DestTy, SrcTy, DestST, Name, PointerTypes);
149 // LinkTypes - Go through the symbol table of the Src module and see if any
150 // types are named in the src module that are not named in the Dst module.
151 // Make sure there are no type name conflicts.
153 static bool LinkTypes(Module *Dest, const Module *Src, std::string *Err) {
154 SymbolTable *DestST = &Dest->getSymbolTable();
155 const SymbolTable *SrcST = &Src->getSymbolTable();
157 // Look for a type plane for Type's...
158 SymbolTable::const_iterator PI = SrcST->find(Type::TypeTy);
159 if (PI == SrcST->end()) return false; // No named types, do nothing.
161 // Some types cannot be resolved immediately because they depend on other
162 // types being resolved to each other first. This contains a list of types we
163 // are waiting to recheck.
164 std::vector<std::string> DelayedTypesToResolve;
166 const SymbolTable::VarMap &VM = PI->second;
167 for (SymbolTable::type_const_iterator I = VM.begin(), E = VM.end();
169 const std::string &Name = I->first;
170 Type *RHS = cast<Type>(I->second);
172 // Check to see if this type name is already in the dest module...
173 Type *Entry = cast_or_null<Type>(DestST->lookup(Type::TypeTy, Name));
175 if (ResolveTypes(Entry, RHS, DestST, Name)) {
176 // They look different, save the types 'till later to resolve.
177 DelayedTypesToResolve.push_back(Name);
181 // Iteratively resolve types while we can...
182 while (!DelayedTypesToResolve.empty()) {
183 // Loop over all of the types, attempting to resolve them if possible...
184 unsigned OldSize = DelayedTypesToResolve.size();
186 // Try direct resolution by name...
187 for (unsigned i = 0; i != DelayedTypesToResolve.size(); ++i) {
188 const std::string &Name = DelayedTypesToResolve[i];
189 Type *T1 = cast<Type>(VM.find(Name)->second);
190 Type *T2 = cast<Type>(DestST->lookup(Type::TypeTy, Name));
191 if (!ResolveTypes(T2, T1, DestST, Name)) {
192 // We are making progress!
193 DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i);
198 // Did we not eliminate any types?
199 if (DelayedTypesToResolve.size() == OldSize) {
200 // Attempt to resolve subelements of types. This allows us to merge these
201 // two types: { int* } and { opaque* }
202 for (unsigned i = 0, e = DelayedTypesToResolve.size(); i != e; ++i) {
203 const std::string &Name = DelayedTypesToResolve[i];
204 PATypeHolder T1(cast<Type>(VM.find(Name)->second));
205 PATypeHolder T2(cast<Type>(DestST->lookup(Type::TypeTy, Name)));
207 if (!RecursiveResolveTypes(T2, T1, DestST, Name)) {
208 // We are making progress!
209 DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i);
211 // Go back to the main loop, perhaps we can resolve directly by name
217 // If we STILL cannot resolve the types, then there is something wrong.
219 if (DelayedTypesToResolve.size() == OldSize) {
220 // Build up an error message of all of the mismatched types.
221 std::string ErrorMessage;
222 for (unsigned i = 0, e = DelayedTypesToResolve.size(); i != e; ++i) {
223 const std::string &Name = DelayedTypesToResolve[i];
224 const Type *T1 = cast<Type>(VM.find(Name)->second);
225 const Type *T2 = cast<Type>(DestST->lookup(Type::TypeTy, Name));
226 ErrorMessage += " Type named '" + Name +
227 "' conflicts.\n Src='" + T1->getDescription() +
228 "'.\n Dest='" + T2->getDescription() + "'\n";
230 return Error(Err, "Type conflict between types in modules:\n" +
240 static void PrintMap(const std::map<const Value*, Value*> &M) {
241 for (std::map<const Value*, Value*>::const_iterator I = M.begin(), E =M.end();
243 std::cerr << " Fr: " << (void*)I->first << " ";
245 std::cerr << " To: " << (void*)I->second << " ";
252 // RemapOperand - Use LocalMap and GlobalMap to convert references from one
253 // module to another. This is somewhat sophisticated in that it can
254 // automatically handle constant references correctly as well...
256 static Value *RemapOperand(const Value *In,
257 std::map<const Value*, Value*> &LocalMap,
258 std::map<const Value*, Value*> *GlobalMap) {
259 std::map<const Value*,Value*>::const_iterator I = LocalMap.find(In);
260 if (I != LocalMap.end()) return I->second;
263 I = GlobalMap->find(In);
264 if (I != GlobalMap->end()) return I->second;
267 // Check to see if it's a constant that we are interesting in transforming...
268 if (const Constant *CPV = dyn_cast<Constant>(In)) {
269 if (!isa<DerivedType>(CPV->getType()) && !isa<ConstantExpr>(CPV))
270 return const_cast<Constant*>(CPV); // Simple constants stay identical...
272 Constant *Result = 0;
274 if (const ConstantArray *CPA = dyn_cast<ConstantArray>(CPV)) {
275 const std::vector<Use> &Ops = CPA->getValues();
276 std::vector<Constant*> Operands(Ops.size());
277 for (unsigned i = 0, e = Ops.size(); i != e; ++i)
279 cast<Constant>(RemapOperand(Ops[i], LocalMap, GlobalMap));
280 Result = ConstantArray::get(cast<ArrayType>(CPA->getType()), Operands);
281 } else if (const ConstantStruct *CPS = dyn_cast<ConstantStruct>(CPV)) {
282 const std::vector<Use> &Ops = CPS->getValues();
283 std::vector<Constant*> Operands(Ops.size());
284 for (unsigned i = 0; i < Ops.size(); ++i)
286 cast<Constant>(RemapOperand(Ops[i], LocalMap, GlobalMap));
287 Result = ConstantStruct::get(cast<StructType>(CPS->getType()), Operands);
288 } else if (isa<ConstantPointerNull>(CPV)) {
289 Result = const_cast<Constant*>(CPV);
290 } else if (const ConstantPointerRef *CPR =
291 dyn_cast<ConstantPointerRef>(CPV)) {
292 Value *V = RemapOperand(CPR->getValue(), LocalMap, GlobalMap);
293 Result = ConstantPointerRef::get(cast<GlobalValue>(V));
294 } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CPV)) {
295 if (CE->getOpcode() == Instruction::GetElementPtr) {
296 Value *Ptr = RemapOperand(CE->getOperand(0), LocalMap, GlobalMap);
297 std::vector<Constant*> Indices;
298 Indices.reserve(CE->getNumOperands()-1);
299 for (unsigned i = 1, e = CE->getNumOperands(); i != e; ++i)
300 Indices.push_back(cast<Constant>(RemapOperand(CE->getOperand(i),
301 LocalMap, GlobalMap)));
303 Result = ConstantExpr::getGetElementPtr(cast<Constant>(Ptr), Indices);
304 } else if (CE->getNumOperands() == 1) {
306 assert(CE->getOpcode() == Instruction::Cast);
307 Value *V = RemapOperand(CE->getOperand(0), LocalMap, GlobalMap);
308 Result = ConstantExpr::getCast(cast<Constant>(V), CE->getType());
309 } else if (CE->getNumOperands() == 2) {
310 // Binary operator...
311 Value *V1 = RemapOperand(CE->getOperand(0), LocalMap, GlobalMap);
312 Value *V2 = RemapOperand(CE->getOperand(1), LocalMap, GlobalMap);
314 Result = ConstantExpr::get(CE->getOpcode(), cast<Constant>(V1),
317 assert(0 && "Unknown constant expr type!");
321 assert(0 && "Unknown type of derived type constant value!");
324 // Cache the mapping in our local map structure...
326 GlobalMap->insert(std::make_pair(In, Result));
328 LocalMap.insert(std::make_pair(In, Result));
332 std::cerr << "XXX LocalMap: \n";
336 std::cerr << "XXX GlobalMap: \n";
337 PrintMap(*GlobalMap);
340 std::cerr << "Couldn't remap value: " << (void*)In << " " << *In << "\n";
341 assert(0 && "Couldn't remap value!");
345 /// FindGlobalNamed - Look in the specified symbol table for a global with the
346 /// specified name and type. If an exactly matching global does not exist, see
347 /// if there is a global which is "type compatible" with the specified
348 /// name/type. This allows us to resolve things like '%x = global int*' with
349 /// '%x = global opaque*'.
351 static GlobalValue *FindGlobalNamed(const std::string &Name, const Type *Ty,
353 // See if an exact match exists in the symbol table...
354 if (Value *V = ST->lookup(Ty, Name)) return cast<GlobalValue>(V);
356 // It doesn't exist exactly, scan through all of the type planes in the symbol
357 // table, checking each of them for a type-compatible version.
359 for (SymbolTable::iterator I = ST->begin(), E = ST->end(); I != E; ++I)
360 if (I->first != Type::TypeTy) {
361 SymbolTable::VarMap &VM = I->second;
362 // Does this type plane contain an entry with the specified name?
363 SymbolTable::type_iterator TI = VM.find(Name);
364 if (TI != VM.end()) {
365 // Determine whether we can fold the two types together, resolving them.
366 // If so, we can use this value.
367 if (!RecursiveResolveTypes(Ty, I->first, ST, ""))
368 return cast<GlobalValue>(TI->second);
371 return 0; // Otherwise, nothing could be found.
375 // LinkGlobals - Loop through the global variables in the src module and merge
376 // them into the dest module.
378 static bool LinkGlobals(Module *Dest, const Module *Src,
379 std::map<const Value*, Value*> &ValueMap,
380 std::multimap<std::string, GlobalVariable *> &AppendingVars,
382 // We will need a module level symbol table if the src module has a module
383 // level symbol table...
384 SymbolTable *ST = (SymbolTable*)&Dest->getSymbolTable();
386 // Loop over all of the globals in the src module, mapping them over as we go
388 for (Module::const_giterator I = Src->gbegin(), E = Src->gend(); I != E; ++I){
389 const GlobalVariable *SGV = I;
390 GlobalVariable *DGV = 0;
391 if (SGV->hasName()) {
392 // A same named thing is a global variable, because the only two things
393 // that may be in a module level symbol table are Global Vars and
394 // Functions, and they both have distinct, nonoverlapping, possible types.
396 DGV = cast_or_null<GlobalVariable>(FindGlobalNamed(SGV->getName(),
397 SGV->getType(), ST));
400 assert(SGV->hasInitializer() || SGV->hasExternalLinkage() &&
401 "Global must either be external or have an initializer!");
403 bool SGExtern = SGV->isExternal();
404 bool DGExtern = DGV ? DGV->isExternal() : false;
406 if (!DGV || DGV->hasInternalLinkage() || SGV->hasInternalLinkage()) {
407 // No linking to be performed, simply create an identical version of the
408 // symbol over in the dest module... the initializer will be filled in
409 // later by LinkGlobalInits...
411 GlobalVariable *NewDGV =
412 new GlobalVariable(SGV->getType()->getElementType(),
413 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
414 SGV->getName(), Dest);
416 // If the LLVM runtime renamed the global, but it is an externally visible
417 // symbol, DGV must be an existing global with internal linkage. Rename
419 if (NewDGV->getName() != SGV->getName() && !NewDGV->hasInternalLinkage()){
420 assert(DGV && DGV->getName() == SGV->getName() &&
421 DGV->hasInternalLinkage());
423 NewDGV->setName(SGV->getName()); // Force the name back
424 DGV->setName(SGV->getName()); // This will cause a renaming
425 assert(NewDGV->getName() == SGV->getName() &&
426 DGV->getName() != SGV->getName());
429 // Make sure to remember this mapping...
430 ValueMap.insert(std::make_pair(SGV, NewDGV));
431 if (SGV->hasAppendingLinkage())
432 // Keep track that this is an appending variable...
433 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV));
435 } else if (SGV->isExternal()) {
436 // If SGV is external or if both SGV & DGV are external.. Just link the
437 // external globals, we aren't adding anything.
438 ValueMap.insert(std::make_pair(SGV, DGV));
440 } else if (DGV->isExternal()) { // If DGV is external but SGV is not...
441 ValueMap.insert(std::make_pair(SGV, DGV));
442 DGV->setLinkage(SGV->getLinkage()); // Inherit linkage!
443 } else if (SGV->hasWeakLinkage()) {
444 // At this point we know that DGV has LinkOnce, Appending, Weak, or
445 // External linkage. If DGV is Appending, this is an error.
446 if (DGV->hasAppendingLinkage())
447 return Error(Err, "Linking globals named '" + SGV->getName() +
448 " ' with 'weak' and 'appending' linkage is not allowed!");
449 // Otherwise, just perform the link.
450 ValueMap.insert(std::make_pair(SGV, DGV));
451 } else if (DGV->hasWeakLinkage()) {
452 // At this point we know that SGV has LinkOnce, Appending, or External
453 // linkage. If SGV is Appending, this is an error.
454 if (SGV->hasAppendingLinkage())
455 return Error(Err, "Linking globals named '" + SGV->getName() +
456 " ' with 'weak' and 'appending' linkage is not allowed!");
457 if (!SGV->hasLinkOnceLinkage())
458 DGV->setLinkage(SGV->getLinkage()); // Inherit linkage!
459 ValueMap.insert(std::make_pair(SGV, DGV));
461 } else if (SGV->getLinkage() != DGV->getLinkage()) {
462 return Error(Err, "Global variables named '" + SGV->getName() +
463 "' have different linkage specifiers!");
464 } else if (SGV->hasExternalLinkage()) {
465 // Allow linking two exactly identical external global variables...
466 if (SGV->isConstant() != DGV->isConstant())
467 return Error(Err, "Global Variable Collision on '" +
468 SGV->getType()->getDescription() + " %" + SGV->getName() +
469 "' - Global variables differ in const'ness");
471 if (SGV->getInitializer() != DGV->getInitializer())
472 return Error(Err, "Global Variable Collision on '" +
473 SGV->getType()->getDescription() + " %" + SGV->getName() +
474 "' - External linkage globals have different initializers");
476 ValueMap.insert(std::make_pair(SGV, DGV));
477 } else if (SGV->hasLinkOnceLinkage()) {
478 // If the global variable has a name, and that name is already in use in
479 // the Dest module, make sure that the name is a compatible global
482 // Check to see if the two GV's have the same Const'ness...
483 if (SGV->isConstant() != DGV->isConstant())
484 return Error(Err, "Global Variable Collision on '" +
485 SGV->getType()->getDescription() + " %" + SGV->getName() +
486 "' - Global variables differ in const'ness");
488 // Okay, everything is cool, remember the mapping...
489 ValueMap.insert(std::make_pair(SGV, DGV));
490 } else if (SGV->hasAppendingLinkage()) {
491 // No linking is performed yet. Just insert a new copy of the global, and
492 // keep track of the fact that it is an appending variable in the
493 // AppendingVars map. The name is cleared out so that no linkage is
495 GlobalVariable *NewDGV =
496 new GlobalVariable(SGV->getType()->getElementType(),
497 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
500 // Make sure to remember this mapping...
501 ValueMap.insert(std::make_pair(SGV, NewDGV));
503 // Keep track that this is an appending variable...
504 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV));
506 assert(0 && "Unknown linkage!");
513 // LinkGlobalInits - Update the initializers in the Dest module now that all
514 // globals that may be referenced are in Dest.
516 static bool LinkGlobalInits(Module *Dest, const Module *Src,
517 std::map<const Value*, Value*> &ValueMap,
520 // Loop over all of the globals in the src module, mapping them over as we go
522 for (Module::const_giterator I = Src->gbegin(), E = Src->gend(); I != E; ++I){
523 const GlobalVariable *SGV = I;
525 if (SGV->hasInitializer()) { // Only process initialized GV's
526 // Figure out what the initializer looks like in the dest module...
528 cast<Constant>(RemapOperand(SGV->getInitializer(), ValueMap, 0));
530 GlobalVariable *DGV = cast<GlobalVariable>(ValueMap[SGV]);
531 if (DGV->hasInitializer()) {
532 assert(SGV->getLinkage() == DGV->getLinkage());
533 if (SGV->hasExternalLinkage()) {
534 if (DGV->getInitializer() != SInit)
535 return Error(Err, "Global Variable Collision on '" +
536 SGV->getType()->getDescription() +"':%"+SGV->getName()+
537 " - Global variables have different initializers");
538 } else if (DGV->hasLinkOnceLinkage() || DGV->hasWeakLinkage()) {
539 // Nothing is required, mapped values will take the new global
541 } else if (DGV->hasAppendingLinkage()) {
542 assert(0 && "Appending linkage unimplemented!");
544 assert(0 && "Unknown linkage!");
547 // Copy the initializer over now...
548 DGV->setInitializer(SInit);
555 // LinkFunctionProtos - Link the functions together between the two modules,
556 // without doing function bodies... this just adds external function prototypes
557 // to the Dest function...
559 static bool LinkFunctionProtos(Module *Dest, const Module *Src,
560 std::map<const Value*, Value*> &ValueMap,
562 SymbolTable *ST = (SymbolTable*)&Dest->getSymbolTable();
564 // Loop over all of the functions in the src module, mapping them over as we
567 for (Module::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) {
568 const Function *SF = I; // SrcFunction
571 // The same named thing is a Function, because the only two things
572 // that may be in a module level symbol table are Global Vars and
573 // Functions, and they both have distinct, nonoverlapping, possible types.
575 DF = cast_or_null<Function>(FindGlobalNamed(SF->getName(), SF->getType(),
578 if (!DF || SF->hasInternalLinkage() || DF->hasInternalLinkage()) {
579 // Function does not already exist, simply insert an function signature
580 // identical to SF into the dest module...
581 Function *NewDF = new Function(SF->getFunctionType(), SF->getLinkage(),
582 SF->getName(), Dest);
584 // If the LLVM runtime renamed the function, but it is an externally
585 // visible symbol, DF must be an existing function with internal linkage.
587 if (NewDF->getName() != SF->getName() && !NewDF->hasInternalLinkage()) {
588 assert(DF && DF->getName() == SF->getName() &&DF->hasInternalLinkage());
590 NewDF->setName(SF->getName()); // Force the name back
591 DF->setName(SF->getName()); // This will cause a renaming
592 assert(NewDF->getName() == SF->getName() &&
593 DF->getName() != SF->getName());
596 // ... and remember this mapping...
597 ValueMap.insert(std::make_pair(SF, NewDF));
598 } else if (SF->isExternal()) {
599 // If SF is external or if both SF & DF are external.. Just link the
600 // external functions, we aren't adding anything.
601 ValueMap.insert(std::make_pair(SF, DF));
602 } else if (DF->isExternal()) { // If DF is external but SF is not...
603 // Link the external functions, update linkage qualifiers
604 ValueMap.insert(std::make_pair(SF, DF));
605 DF->setLinkage(SF->getLinkage());
607 } else if (SF->hasWeakLinkage()) {
608 // At this point we know that DF has LinkOnce, Weak, or External linkage.
609 ValueMap.insert(std::make_pair(SF, DF));
611 } else if (DF->hasWeakLinkage()) {
612 // At this point we know that SF has LinkOnce or External linkage.
613 ValueMap.insert(std::make_pair(SF, DF));
614 if (!SF->hasLinkOnceLinkage()) // Don't inherit linkonce linkage
615 DF->setLinkage(SF->getLinkage());
617 } else if (SF->getLinkage() != DF->getLinkage()) {
618 return Error(Err, "Functions named '" + SF->getName() +
619 "' have different linkage specifiers!");
620 } else if (SF->hasExternalLinkage()) {
621 // The function is defined in both modules!!
622 return Error(Err, "Function '" +
623 SF->getFunctionType()->getDescription() + "':\"" +
624 SF->getName() + "\" - Function is already defined!");
625 } else if (SF->hasLinkOnceLinkage()) {
626 // Completely ignore the source function.
627 ValueMap.insert(std::make_pair(SF, DF));
629 assert(0 && "Unknown linkage configuration found!");
635 // LinkFunctionBody - Copy the source function over into the dest function and
636 // fix up references to values. At this point we know that Dest is an external
637 // function, and that Src is not.
639 static bool LinkFunctionBody(Function *Dest, const Function *Src,
640 std::map<const Value*, Value*> &GlobalMap,
642 assert(Src && Dest && Dest->isExternal() && !Src->isExternal());
643 std::map<const Value*, Value*> LocalMap; // Map for function local values
645 // Go through and convert function arguments over...
646 Function::aiterator DI = Dest->abegin();
647 for (Function::const_aiterator I = Src->abegin(), E = Src->aend();
649 DI->setName(I->getName()); // Copy the name information over...
651 // Add a mapping to our local map
652 LocalMap.insert(std::make_pair(I, DI));
655 // Loop over all of the basic blocks, copying the instructions over...
657 for (Function::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) {
658 // Create new basic block and add to mapping and the Dest function...
659 BasicBlock *DBB = new BasicBlock(I->getName(), Dest);
660 LocalMap.insert(std::make_pair(I, DBB));
662 // Loop over all of the instructions in the src basic block, copying them
663 // over. Note that this is broken in a strict sense because the cloned
664 // instructions will still be referencing values in the Src module, not
665 // the remapped values. In our case, however, we will not get caught and
666 // so we can delay patching the values up until later...
668 for (BasicBlock::const_iterator II = I->begin(), IE = I->end();
670 Instruction *DI = II->clone();
671 DI->setName(II->getName());
672 DBB->getInstList().push_back(DI);
673 LocalMap.insert(std::make_pair(II, DI));
677 // At this point, all of the instructions and values of the function are now
678 // copied over. The only problem is that they are still referencing values in
679 // the Source function as operands. Loop through all of the operands of the
680 // functions and patch them up to point to the local versions...
682 for (Function::iterator BB = Dest->begin(), BE = Dest->end(); BB != BE; ++BB)
683 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
684 for (Instruction::op_iterator OI = I->op_begin(), OE = I->op_end();
686 *OI = RemapOperand(*OI, LocalMap, &GlobalMap);
692 // LinkFunctionBodies - Link in the function bodies that are defined in the
693 // source module into the DestModule. This consists basically of copying the
694 // function over and fixing up references to values.
696 static bool LinkFunctionBodies(Module *Dest, const Module *Src,
697 std::map<const Value*, Value*> &ValueMap,
700 // Loop over all of the functions in the src module, mapping them over as we
703 for (Module::const_iterator SF = Src->begin(), E = Src->end(); SF != E; ++SF){
704 if (!SF->isExternal()) { // No body if function is external
705 Function *DF = cast<Function>(ValueMap[SF]); // Destination function
707 // DF not external SF external?
708 if (!DF->isExternal()) {
709 if (DF->hasLinkOnceLinkage()) continue; // No relinkage for link-once!
710 if (SF->hasWeakLinkage()) continue;
711 return Error(Err, "Function '" + SF->getName() +
712 "' body multiply defined!");
715 if (LinkFunctionBody(DF, SF, ValueMap, Err)) return true;
721 // LinkAppendingVars - If there were any appending global variables, link them
722 // together now. Return true on error.
724 static bool LinkAppendingVars(Module *M,
725 std::multimap<std::string, GlobalVariable *> &AppendingVars,
726 std::string *ErrorMsg) {
727 if (AppendingVars.empty()) return false; // Nothing to do.
729 // Loop over the multimap of appending vars, processing any variables with the
730 // same name, forming a new appending global variable with both of the
731 // initializers merged together, then rewrite references to the old variables
734 std::vector<Constant*> Inits;
735 while (AppendingVars.size() > 1) {
736 // Get the first two elements in the map...
737 std::multimap<std::string,
738 GlobalVariable*>::iterator Second = AppendingVars.begin(), First=Second++;
740 // If the first two elements are for different names, there is no pair...
741 // Otherwise there is a pair, so link them together...
742 if (First->first == Second->first) {
743 GlobalVariable *G1 = First->second, *G2 = Second->second;
744 const ArrayType *T1 = cast<ArrayType>(G1->getType()->getElementType());
745 const ArrayType *T2 = cast<ArrayType>(G2->getType()->getElementType());
747 // Check to see that they two arrays agree on type...
748 if (T1->getElementType() != T2->getElementType())
749 return Error(ErrorMsg,
750 "Appending variables with different element types need to be linked!");
751 if (G1->isConstant() != G2->isConstant())
752 return Error(ErrorMsg,
753 "Appending variables linked with different const'ness!");
755 unsigned NewSize = T1->getNumElements() + T2->getNumElements();
756 ArrayType *NewType = ArrayType::get(T1->getElementType(), NewSize);
758 // Create the new global variable...
760 new GlobalVariable(NewType, G1->isConstant(), G1->getLinkage(),
761 /*init*/0, First->first, M);
763 // Merge the initializer...
764 Inits.reserve(NewSize);
765 ConstantArray *I = cast<ConstantArray>(G1->getInitializer());
766 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i)
767 Inits.push_back(cast<Constant>(I->getValues()[i]));
768 I = cast<ConstantArray>(G2->getInitializer());
769 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i)
770 Inits.push_back(cast<Constant>(I->getValues()[i]));
771 NG->setInitializer(ConstantArray::get(NewType, Inits));
774 // Replace any uses of the two global variables with uses of the new
777 // FIXME: This should rewrite simple/straight-forward uses such as
778 // getelementptr instructions to not use the Cast!
779 ConstantPointerRef *NGCP = ConstantPointerRef::get(NG);
780 G1->replaceAllUsesWith(ConstantExpr::getCast(NGCP, G1->getType()));
781 G2->replaceAllUsesWith(ConstantExpr::getCast(NGCP, G2->getType()));
783 // Remove the two globals from the module now...
784 M->getGlobalList().erase(G1);
785 M->getGlobalList().erase(G2);
787 // Put the new global into the AppendingVars map so that we can handle
788 // linking of more than two vars...
791 AppendingVars.erase(First);
798 // LinkModules - This function links two modules together, with the resulting
799 // left module modified to be the composite of the two input modules. If an
800 // error occurs, true is returned and ErrorMsg (if not null) is set to indicate
801 // the problem. Upon failure, the Dest module could be in a modified state, and
802 // shouldn't be relied on to be consistent.
804 bool LinkModules(Module *Dest, const Module *Src, std::string *ErrorMsg) {
805 if (Dest->getEndianness() == Module::AnyEndianness)
806 Dest->setEndianness(Src->getEndianness());
807 if (Dest->getPointerSize() == Module::AnyPointerSize)
808 Dest->setPointerSize(Src->getPointerSize());
810 if (Src->getEndianness() != Module::AnyEndianness &&
811 Dest->getEndianness() != Src->getEndianness())
812 std::cerr << "WARNING: Linking two modules of different endianness!\n";
813 if (Src->getPointerSize() != Module::AnyPointerSize &&
814 Dest->getPointerSize() != Src->getPointerSize())
815 std::cerr << "WARNING: Linking two modules of different pointer size!\n";
817 // LinkTypes - Go through the symbol table of the Src module and see if any
818 // types are named in the src module that are not named in the Dst module.
819 // Make sure there are no type name conflicts.
821 if (LinkTypes(Dest, Src, ErrorMsg)) return true;
823 // ValueMap - Mapping of values from what they used to be in Src, to what they
826 std::map<const Value*, Value*> ValueMap;
828 // AppendingVars - Keep track of global variables in the destination module
829 // with appending linkage. After the module is linked together, they are
830 // appended and the module is rewritten.
832 std::multimap<std::string, GlobalVariable *> AppendingVars;
834 // Add all of the appending globals already in the Dest module to
836 for (Module::giterator I = Dest->gbegin(), E = Dest->gend(); I != E; ++I)
837 if (I->hasAppendingLinkage())
838 AppendingVars.insert(std::make_pair(I->getName(), I));
840 // Insert all of the globals in src into the Dest module... without linking
841 // initializers (which could refer to functions not yet mapped over).
843 if (LinkGlobals(Dest, Src, ValueMap, AppendingVars, ErrorMsg)) return true;
845 // Link the functions together between the two modules, without doing function
846 // bodies... this just adds external function prototypes to the Dest
847 // function... We do this so that when we begin processing function bodies,
848 // all of the global values that may be referenced are available in our
851 if (LinkFunctionProtos(Dest, Src, ValueMap, ErrorMsg)) return true;
853 // Update the initializers in the Dest module now that all globals that may
854 // be referenced are in Dest.
856 if (LinkGlobalInits(Dest, Src, ValueMap, ErrorMsg)) return true;
858 // Link in the function bodies that are defined in the source module into the
859 // DestModule. This consists basically of copying the function over and
860 // fixing up references to values.
862 if (LinkFunctionBodies(Dest, Src, ValueMap, ErrorMsg)) return true;
864 // If there were any appending global variables, link them together now.
866 if (LinkAppendingVars(Dest, AppendingVars, ErrorMsg)) return true;