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) {
35 // Function: ResolveTypes()
38 // Attempt to link the two specified types together.
41 // DestTy - The type to which we wish to resolve.
42 // SrcTy - The original type which we want to resolve.
43 // Name - The name of the type.
46 // DestST - The symbol table in which the new type should be placed.
49 // true - There is an error and the types cannot yet be linked.
52 static bool ResolveTypes(const Type *DestTy, const Type *SrcTy,
53 SymbolTable *DestST, const std::string &Name) {
54 if (DestTy == SrcTy) return false; // If already equal, noop
56 // Does the type already exist in the module?
57 if (DestTy && !isa<OpaqueType>(DestTy)) { // Yup, the type already exists...
58 if (const OpaqueType *OT = dyn_cast<OpaqueType>(SrcTy)) {
59 const_cast<OpaqueType*>(OT)->refineAbstractTypeTo(DestTy);
61 return true; // Cannot link types... neither is opaque and not-equal
63 } else { // Type not in dest module. Add it now.
64 if (DestTy) // Type _is_ in module, just opaque...
65 const_cast<OpaqueType*>(cast<OpaqueType>(DestTy))
66 ->refineAbstractTypeTo(SrcTy);
67 else if (!Name.empty())
68 DestST->insert(Name, const_cast<Type*>(SrcTy));
73 static const FunctionType *getFT(const PATypeHolder &TH) {
74 return cast<FunctionType>(TH.get());
76 static const StructType *getST(const PATypeHolder &TH) {
77 return cast<StructType>(TH.get());
80 // RecursiveResolveTypes - This is just like ResolveTypes, except that it
81 // recurses down into derived types, merging the used types if the parent types
84 static bool RecursiveResolveTypesI(const PATypeHolder &DestTy,
85 const PATypeHolder &SrcTy,
86 SymbolTable *DestST, const std::string &Name,
87 std::vector<std::pair<PATypeHolder, PATypeHolder> > &Pointers) {
88 const Type *SrcTyT = SrcTy.get();
89 const Type *DestTyT = DestTy.get();
90 if (DestTyT == SrcTyT) return false; // If already equal, noop
92 // If we found our opaque type, resolve it now!
93 if (isa<OpaqueType>(DestTyT) || isa<OpaqueType>(SrcTyT))
94 return ResolveTypes(DestTyT, SrcTyT, DestST, Name);
96 // Two types cannot be resolved together if they are of different primitive
97 // type. For example, we cannot resolve an int to a float.
98 if (DestTyT->getPrimitiveID() != SrcTyT->getPrimitiveID()) return true;
100 // Otherwise, resolve the used type used by this derived type...
101 switch (DestTyT->getPrimitiveID()) {
102 case Type::FunctionTyID: {
103 if (cast<FunctionType>(DestTyT)->isVarArg() !=
104 cast<FunctionType>(SrcTyT)->isVarArg() ||
105 cast<FunctionType>(DestTyT)->getNumContainedTypes() !=
106 cast<FunctionType>(SrcTyT)->getNumContainedTypes())
108 for (unsigned i = 0, e = getFT(DestTy)->getNumContainedTypes(); i != e; ++i)
109 if (RecursiveResolveTypesI(getFT(DestTy)->getContainedType(i),
110 getFT(SrcTy)->getContainedType(i), DestST, "",
115 case Type::StructTyID: {
116 if (getST(DestTy)->getNumContainedTypes() !=
117 getST(SrcTy)->getNumContainedTypes()) return 1;
118 for (unsigned i = 0, e = getST(DestTy)->getNumContainedTypes(); i != e; ++i)
119 if (RecursiveResolveTypesI(getST(DestTy)->getContainedType(i),
120 getST(SrcTy)->getContainedType(i), DestST, "",
125 case Type::ArrayTyID: {
126 const ArrayType *DAT = cast<ArrayType>(DestTy.get());
127 const ArrayType *SAT = cast<ArrayType>(SrcTy.get());
128 if (DAT->getNumElements() != SAT->getNumElements()) return true;
129 return RecursiveResolveTypesI(DAT->getElementType(), SAT->getElementType(),
130 DestST, "", Pointers);
132 case Type::PointerTyID: {
133 // If this is a pointer type, check to see if we have already seen it. If
134 // so, we are in a recursive branch. Cut off the search now. We cannot use
135 // an associative container for this search, because the type pointers (keys
136 // in the container) change whenever types get resolved...
138 for (unsigned i = 0, e = Pointers.size(); i != e; ++i)
139 if (Pointers[i].first == DestTy)
140 return Pointers[i].second != SrcTy;
142 // Otherwise, add the current pointers to the vector to stop recursion on
144 Pointers.push_back(std::make_pair(DestTyT, SrcTyT));
146 RecursiveResolveTypesI(cast<PointerType>(DestTy.get())->getElementType(),
147 cast<PointerType>(SrcTy.get())->getElementType(),
148 DestST, "", Pointers);
152 default: assert(0 && "Unexpected type!"); return true;
156 static bool RecursiveResolveTypes(const PATypeHolder &DestTy,
157 const PATypeHolder &SrcTy,
158 SymbolTable *DestST, const std::string &Name){
159 std::vector<std::pair<PATypeHolder, PATypeHolder> > PointerTypes;
160 return RecursiveResolveTypesI(DestTy, SrcTy, DestST, Name, PointerTypes);
164 // LinkTypes - Go through the symbol table of the Src module and see if any
165 // types are named in the src module that are not named in the Dst module.
166 // Make sure there are no type name conflicts.
168 static bool LinkTypes(Module *Dest, const Module *Src, std::string *Err) {
169 SymbolTable *DestST = &Dest->getSymbolTable();
170 const SymbolTable *SrcST = &Src->getSymbolTable();
172 // Look for a type plane for Type's...
173 SymbolTable::const_iterator PI = SrcST->find(Type::TypeTy);
174 if (PI == SrcST->end()) return false; // No named types, do nothing.
176 // Some types cannot be resolved immediately because they depend on other
177 // types being resolved to each other first. This contains a list of types we
178 // are waiting to recheck.
179 std::vector<std::string> DelayedTypesToResolve;
181 const SymbolTable::VarMap &VM = PI->second;
182 for (SymbolTable::type_const_iterator I = VM.begin(), E = VM.end();
184 const std::string &Name = I->first;
185 Type *RHS = cast<Type>(I->second);
187 // Check to see if this type name is already in the dest module...
188 Type *Entry = cast_or_null<Type>(DestST->lookup(Type::TypeTy, Name));
190 if (ResolveTypes(Entry, RHS, DestST, Name)) {
191 // They look different, save the types 'till later to resolve.
192 DelayedTypesToResolve.push_back(Name);
196 // Iteratively resolve types while we can...
197 while (!DelayedTypesToResolve.empty()) {
198 // Loop over all of the types, attempting to resolve them if possible...
199 unsigned OldSize = DelayedTypesToResolve.size();
201 // Try direct resolution by name...
202 for (unsigned i = 0; i != DelayedTypesToResolve.size(); ++i) {
203 const std::string &Name = DelayedTypesToResolve[i];
204 Type *T1 = cast<Type>(VM.find(Name)->second);
205 Type *T2 = cast<Type>(DestST->lookup(Type::TypeTy, Name));
206 if (!ResolveTypes(T2, T1, DestST, Name)) {
207 // We are making progress!
208 DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i);
213 // Did we not eliminate any types?
214 if (DelayedTypesToResolve.size() == OldSize) {
215 // Attempt to resolve subelements of types. This allows us to merge these
216 // two types: { int* } and { opaque* }
217 for (unsigned i = 0, e = DelayedTypesToResolve.size(); i != e; ++i) {
218 const std::string &Name = DelayedTypesToResolve[i];
219 PATypeHolder T1(cast<Type>(VM.find(Name)->second));
220 PATypeHolder T2(cast<Type>(DestST->lookup(Type::TypeTy, Name)));
222 if (!RecursiveResolveTypes(T2, T1, DestST, Name)) {
223 // We are making progress!
224 DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i);
226 // Go back to the main loop, perhaps we can resolve directly by name
232 // If we STILL cannot resolve the types, then there is something wrong.
233 // Report the warning and delete one of the names.
234 if (DelayedTypesToResolve.size() == OldSize) {
235 const std::string &Name = DelayedTypesToResolve.back();
237 const Type *T1 = cast<Type>(VM.find(Name)->second);
238 const Type *T2 = cast<Type>(DestST->lookup(Type::TypeTy, Name));
239 std::cerr << "WARNING: Type conflict between types named '" << Name
240 << "'.\n Src='" << *T1 << "'.\n Dest='" << *T2 << "'\n";
242 // Remove the symbol name from the destination.
243 DelayedTypesToResolve.pop_back();
252 static void PrintMap(const std::map<const Value*, Value*> &M) {
253 for (std::map<const Value*, Value*>::const_iterator I = M.begin(), E =M.end();
255 std::cerr << " Fr: " << (void*)I->first << " ";
257 std::cerr << " To: " << (void*)I->second << " ";
264 // RemapOperand - Use LocalMap and GlobalMap to convert references from one
265 // module to another. This is somewhat sophisticated in that it can
266 // automatically handle constant references correctly as well...
268 static Value *RemapOperand(const Value *In,
269 std::map<const Value*, Value*> &LocalMap,
270 std::map<const Value*, Value*> *GlobalMap) {
271 std::map<const Value*,Value*>::const_iterator I = LocalMap.find(In);
272 if (I != LocalMap.end()) return I->second;
275 I = GlobalMap->find(In);
276 if (I != GlobalMap->end()) return I->second;
279 // Check to see if it's a constant that we are interesting in transforming...
280 if (const Constant *CPV = dyn_cast<Constant>(In)) {
281 if (!isa<DerivedType>(CPV->getType()) && !isa<ConstantExpr>(CPV))
282 return const_cast<Constant*>(CPV); // Simple constants stay identical...
284 Constant *Result = 0;
286 if (const ConstantArray *CPA = dyn_cast<ConstantArray>(CPV)) {
287 const std::vector<Use> &Ops = CPA->getValues();
288 std::vector<Constant*> Operands(Ops.size());
289 for (unsigned i = 0, e = Ops.size(); i != e; ++i)
291 cast<Constant>(RemapOperand(Ops[i], LocalMap, GlobalMap));
292 Result = ConstantArray::get(cast<ArrayType>(CPA->getType()), Operands);
293 } else if (const ConstantStruct *CPS = dyn_cast<ConstantStruct>(CPV)) {
294 const std::vector<Use> &Ops = CPS->getValues();
295 std::vector<Constant*> Operands(Ops.size());
296 for (unsigned i = 0; i < Ops.size(); ++i)
298 cast<Constant>(RemapOperand(Ops[i], LocalMap, GlobalMap));
299 Result = ConstantStruct::get(cast<StructType>(CPS->getType()), Operands);
300 } else if (isa<ConstantPointerNull>(CPV)) {
301 Result = const_cast<Constant*>(CPV);
302 } else if (const ConstantPointerRef *CPR =
303 dyn_cast<ConstantPointerRef>(CPV)) {
304 Value *V = RemapOperand(CPR->getValue(), LocalMap, GlobalMap);
305 Result = ConstantPointerRef::get(cast<GlobalValue>(V));
306 } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CPV)) {
307 if (CE->getOpcode() == Instruction::GetElementPtr) {
308 Value *Ptr = RemapOperand(CE->getOperand(0), LocalMap, GlobalMap);
309 std::vector<Constant*> Indices;
310 Indices.reserve(CE->getNumOperands()-1);
311 for (unsigned i = 1, e = CE->getNumOperands(); i != e; ++i)
312 Indices.push_back(cast<Constant>(RemapOperand(CE->getOperand(i),
313 LocalMap, GlobalMap)));
315 Result = ConstantExpr::getGetElementPtr(cast<Constant>(Ptr), Indices);
316 } else if (CE->getNumOperands() == 1) {
318 assert(CE->getOpcode() == Instruction::Cast);
319 Value *V = RemapOperand(CE->getOperand(0), LocalMap, GlobalMap);
320 Result = ConstantExpr::getCast(cast<Constant>(V), CE->getType());
321 } else if (CE->getNumOperands() == 2) {
322 // Binary operator...
323 Value *V1 = RemapOperand(CE->getOperand(0), LocalMap, GlobalMap);
324 Value *V2 = RemapOperand(CE->getOperand(1), LocalMap, GlobalMap);
326 Result = ConstantExpr::get(CE->getOpcode(), cast<Constant>(V1),
329 assert(0 && "Unknown constant expr type!");
333 assert(0 && "Unknown type of derived type constant value!");
336 // Cache the mapping in our local map structure...
338 GlobalMap->insert(std::make_pair(In, Result));
340 LocalMap.insert(std::make_pair(In, Result));
344 std::cerr << "XXX LocalMap: \n";
348 std::cerr << "XXX GlobalMap: \n";
349 PrintMap(*GlobalMap);
352 std::cerr << "Couldn't remap value: " << (void*)In << " " << *In << "\n";
353 assert(0 && "Couldn't remap value!");
357 /// FindGlobalNamed - Look in the specified symbol table for a global with the
358 /// specified name and type. If an exactly matching global does not exist, see
359 /// if there is a global which is "type compatible" with the specified
360 /// name/type. This allows us to resolve things like '%x = global int*' with
361 /// '%x = global opaque*'.
363 static GlobalValue *FindGlobalNamed(const std::string &Name, const Type *Ty,
365 // See if an exact match exists in the symbol table...
366 if (Value *V = ST->lookup(Ty, Name)) return cast<GlobalValue>(V);
368 // It doesn't exist exactly, scan through all of the type planes in the symbol
369 // table, checking each of them for a type-compatible version.
371 for (SymbolTable::iterator I = ST->begin(), E = ST->end(); I != E; ++I)
372 if (I->first != Type::TypeTy) {
373 SymbolTable::VarMap &VM = I->second;
375 // Does this type plane contain an entry with the specified name?
376 SymbolTable::type_iterator TI = VM.find(Name);
377 if (TI != VM.end()) {
379 // Ensure that this type if placed correctly into the symbol table.
381 assert(TI->second->getType() == I->first && "Type conflict!");
384 // Save a reference to the new type. Resolving the type can modify the
385 // symbol table, invalidating the TI variable.
387 Value *ValPtr = TI->second;
390 // Determine whether we can fold the two types together, resolving them.
391 // If so, we can use this value.
393 if (!RecursiveResolveTypes(Ty, I->first, ST, ""))
394 return cast<GlobalValue>(ValPtr);
397 return 0; // Otherwise, nothing could be found.
401 // LinkGlobals - Loop through the global variables in the src module and merge
402 // them into the dest module.
404 static bool LinkGlobals(Module *Dest, const Module *Src,
405 std::map<const Value*, Value*> &ValueMap,
406 std::multimap<std::string, GlobalVariable *> &AppendingVars,
408 // We will need a module level symbol table if the src module has a module
409 // level symbol table...
410 SymbolTable *ST = (SymbolTable*)&Dest->getSymbolTable();
412 // Loop over all of the globals in the src module, mapping them over as we go
414 for (Module::const_giterator I = Src->gbegin(), E = Src->gend(); I != E; ++I){
415 const GlobalVariable *SGV = I;
416 GlobalVariable *DGV = 0;
417 if (SGV->hasName()) {
418 // A same named thing is a global variable, because the only two things
419 // that may be in a module level symbol table are Global Vars and
420 // Functions, and they both have distinct, nonoverlapping, possible types.
422 DGV = cast_or_null<GlobalVariable>(FindGlobalNamed(SGV->getName(),
423 SGV->getType(), ST));
426 assert(SGV->hasInitializer() || SGV->hasExternalLinkage() &&
427 "Global must either be external or have an initializer!");
429 bool SGExtern = SGV->isExternal();
430 bool DGExtern = DGV ? DGV->isExternal() : false;
432 if (!DGV || DGV->hasInternalLinkage() || SGV->hasInternalLinkage()) {
433 // No linking to be performed, simply create an identical version of the
434 // symbol over in the dest module... the initializer will be filled in
435 // later by LinkGlobalInits...
437 GlobalVariable *NewDGV =
438 new GlobalVariable(SGV->getType()->getElementType(),
439 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
440 SGV->getName(), Dest);
442 // If the LLVM runtime renamed the global, but it is an externally visible
443 // symbol, DGV must be an existing global with internal linkage. Rename
445 if (NewDGV->getName() != SGV->getName() && !NewDGV->hasInternalLinkage()){
446 assert(DGV && DGV->getName() == SGV->getName() &&
447 DGV->hasInternalLinkage());
449 NewDGV->setName(SGV->getName()); // Force the name back
450 DGV->setName(SGV->getName()); // This will cause a renaming
451 assert(NewDGV->getName() == SGV->getName() &&
452 DGV->getName() != SGV->getName());
455 // Make sure to remember this mapping...
456 ValueMap.insert(std::make_pair(SGV, NewDGV));
457 if (SGV->hasAppendingLinkage())
458 // Keep track that this is an appending variable...
459 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV));
461 } else if (SGV->isExternal()) {
462 // If SGV is external or if both SGV & DGV are external.. Just link the
463 // external globals, we aren't adding anything.
464 ValueMap.insert(std::make_pair(SGV, DGV));
466 } else if (DGV->isExternal()) { // If DGV is external but SGV is not...
467 ValueMap.insert(std::make_pair(SGV, DGV));
468 DGV->setLinkage(SGV->getLinkage()); // Inherit linkage!
469 } else if (SGV->hasWeakLinkage() || SGV->hasLinkOnceLinkage()) {
470 // At this point we know that DGV has LinkOnce, Appending, Weak, or
471 // External linkage. If DGV is Appending, this is an error.
472 if (DGV->hasAppendingLinkage())
473 return Error(Err, "Linking globals named '" + SGV->getName() +
474 " ' with 'weak' and 'appending' linkage is not allowed!");
476 if (SGV->isConstant() != DGV->isConstant())
477 return Error(Err, "Global Variable Collision on '" +
478 SGV->getType()->getDescription() + " %" + SGV->getName() +
479 "' - Global variables differ in const'ness");
481 // Otherwise, just perform the link.
482 ValueMap.insert(std::make_pair(SGV, DGV));
484 // Linkonce+Weak = Weak
485 if (DGV->hasLinkOnceLinkage() && SGV->hasWeakLinkage())
486 DGV->setLinkage(SGV->getLinkage());
488 } else if (DGV->hasWeakLinkage() || DGV->hasLinkOnceLinkage()) {
489 // At this point we know that SGV has LinkOnce, Appending, or External
490 // linkage. If SGV is Appending, this is an error.
491 if (SGV->hasAppendingLinkage())
492 return Error(Err, "Linking globals named '" + SGV->getName() +
493 " ' with 'weak' and 'appending' linkage is not allowed!");
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->hasLinkOnceLinkage())
501 DGV->setLinkage(SGV->getLinkage()); // Inherit linkage!
502 ValueMap.insert(std::make_pair(SGV, DGV));
504 } else if (SGV->getLinkage() != DGV->getLinkage()) {
505 return Error(Err, "Global variables named '" + SGV->getName() +
506 "' have different linkage specifiers!");
507 } else if (SGV->hasExternalLinkage()) {
508 // Allow linking two exactly identical external global variables...
509 if (SGV->isConstant() != DGV->isConstant())
510 return Error(Err, "Global Variable Collision on '" +
511 SGV->getType()->getDescription() + " %" + SGV->getName() +
512 "' - Global variables differ in const'ness");
514 if (SGV->getInitializer() != DGV->getInitializer())
515 return Error(Err, "Global Variable Collision on '" +
516 SGV->getType()->getDescription() + " %" + SGV->getName() +
517 "' - External linkage globals have different initializers");
519 ValueMap.insert(std::make_pair(SGV, DGV));
520 } else if (SGV->hasAppendingLinkage()) {
521 // No linking is performed yet. Just insert a new copy of the global, and
522 // keep track of the fact that it is an appending variable in the
523 // AppendingVars map. The name is cleared out so that no linkage is
525 GlobalVariable *NewDGV =
526 new GlobalVariable(SGV->getType()->getElementType(),
527 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
530 // Make sure to remember this mapping...
531 ValueMap.insert(std::make_pair(SGV, NewDGV));
533 // Keep track that this is an appending variable...
534 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV));
536 assert(0 && "Unknown linkage!");
543 // LinkGlobalInits - Update the initializers in the Dest module now that all
544 // globals that may be referenced are in Dest.
546 static bool LinkGlobalInits(Module *Dest, const Module *Src,
547 std::map<const Value*, Value*> &ValueMap,
550 // Loop over all of the globals in the src module, mapping them over as we go
552 for (Module::const_giterator I = Src->gbegin(), E = Src->gend(); I != E; ++I){
553 const GlobalVariable *SGV = I;
555 if (SGV->hasInitializer()) { // Only process initialized GV's
556 // Figure out what the initializer looks like in the dest module...
558 cast<Constant>(RemapOperand(SGV->getInitializer(), ValueMap, 0));
560 GlobalVariable *DGV = cast<GlobalVariable>(ValueMap[SGV]);
561 if (DGV->hasInitializer()) {
562 assert(SGV->getLinkage() == DGV->getLinkage());
563 if (SGV->hasExternalLinkage()) {
564 if (DGV->getInitializer() != SInit)
565 return Error(Err, "Global Variable Collision on '" +
566 SGV->getType()->getDescription() +"':%"+SGV->getName()+
567 " - Global variables have different initializers");
568 } else if (DGV->hasLinkOnceLinkage() || DGV->hasWeakLinkage()) {
569 // Nothing is required, mapped values will take the new global
571 } else if (DGV->hasAppendingLinkage()) {
572 assert(0 && "Appending linkage unimplemented!");
574 assert(0 && "Unknown linkage!");
577 // Copy the initializer over now...
578 DGV->setInitializer(SInit);
585 // LinkFunctionProtos - Link the functions together between the two modules,
586 // without doing function bodies... this just adds external function prototypes
587 // to the Dest function...
589 static bool LinkFunctionProtos(Module *Dest, const Module *Src,
590 std::map<const Value*, Value*> &ValueMap,
592 SymbolTable *ST = (SymbolTable*)&Dest->getSymbolTable();
594 // Loop over all of the functions in the src module, mapping them over as we
597 for (Module::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) {
598 const Function *SF = I; // SrcFunction
601 // The same named thing is a Function, because the only two things
602 // that may be in a module level symbol table are Global Vars and
603 // Functions, and they both have distinct, nonoverlapping, possible types.
605 DF = cast_or_null<Function>(FindGlobalNamed(SF->getName(), SF->getType(),
608 if (!DF || SF->hasInternalLinkage() || DF->hasInternalLinkage()) {
609 // Function does not already exist, simply insert an function signature
610 // identical to SF into the dest module...
611 Function *NewDF = new Function(SF->getFunctionType(), SF->getLinkage(),
612 SF->getName(), Dest);
614 // If the LLVM runtime renamed the function, but it is an externally
615 // visible symbol, DF must be an existing function with internal linkage.
617 if (NewDF->getName() != SF->getName() && !NewDF->hasInternalLinkage()) {
618 assert(DF && DF->getName() == SF->getName() &&DF->hasInternalLinkage());
620 NewDF->setName(SF->getName()); // Force the name back
621 DF->setName(SF->getName()); // This will cause a renaming
622 assert(NewDF->getName() == SF->getName() &&
623 DF->getName() != SF->getName());
626 // ... and remember this mapping...
627 ValueMap.insert(std::make_pair(SF, NewDF));
628 } else if (SF->isExternal()) {
629 // If SF is external or if both SF & DF are external.. Just link the
630 // external functions, we aren't adding anything.
631 ValueMap.insert(std::make_pair(SF, DF));
632 } else if (DF->isExternal()) { // If DF is external but SF is not...
633 // Link the external functions, update linkage qualifiers
634 ValueMap.insert(std::make_pair(SF, DF));
635 DF->setLinkage(SF->getLinkage());
637 } else if (SF->hasWeakLinkage() || SF->hasLinkOnceLinkage()) {
638 // At this point we know that DF has LinkOnce, Weak, or External linkage.
639 ValueMap.insert(std::make_pair(SF, DF));
641 // Linkonce+Weak = Weak
642 if (DF->hasLinkOnceLinkage() && SF->hasWeakLinkage())
643 DF->setLinkage(SF->getLinkage());
645 } else if (DF->hasWeakLinkage() || DF->hasLinkOnceLinkage()) {
646 // At this point we know that SF has LinkOnce or External linkage.
647 ValueMap.insert(std::make_pair(SF, DF));
648 if (!SF->hasLinkOnceLinkage()) // Don't inherit linkonce linkage
649 DF->setLinkage(SF->getLinkage());
651 } else if (SF->getLinkage() != DF->getLinkage()) {
652 return Error(Err, "Functions named '" + SF->getName() +
653 "' have different linkage specifiers!");
654 } else if (SF->hasExternalLinkage()) {
655 // The function is defined in both modules!!
656 return Error(Err, "Function '" +
657 SF->getFunctionType()->getDescription() + "':\"" +
658 SF->getName() + "\" - Function is already defined!");
660 assert(0 && "Unknown linkage configuration found!");
666 // LinkFunctionBody - Copy the source function over into the dest function and
667 // fix up references to values. At this point we know that Dest is an external
668 // function, and that Src is not.
670 static bool LinkFunctionBody(Function *Dest, const Function *Src,
671 std::map<const Value*, Value*> &GlobalMap,
673 assert(Src && Dest && Dest->isExternal() && !Src->isExternal());
674 std::map<const Value*, Value*> LocalMap; // Map for function local values
676 // Go through and convert function arguments over...
677 Function::aiterator DI = Dest->abegin();
678 for (Function::const_aiterator I = Src->abegin(), E = Src->aend();
680 DI->setName(I->getName()); // Copy the name information over...
682 // Add a mapping to our local map
683 LocalMap.insert(std::make_pair(I, DI));
686 // Loop over all of the basic blocks, copying the instructions over...
688 for (Function::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) {
689 // Create new basic block and add to mapping and the Dest function...
690 BasicBlock *DBB = new BasicBlock(I->getName(), Dest);
691 LocalMap.insert(std::make_pair(I, DBB));
693 // Loop over all of the instructions in the src basic block, copying them
694 // over. Note that this is broken in a strict sense because the cloned
695 // instructions will still be referencing values in the Src module, not
696 // the remapped values. In our case, however, we will not get caught and
697 // so we can delay patching the values up until later...
699 for (BasicBlock::const_iterator II = I->begin(), IE = I->end();
701 Instruction *DI = II->clone();
702 DI->setName(II->getName());
703 DBB->getInstList().push_back(DI);
704 LocalMap.insert(std::make_pair(II, DI));
708 // At this point, all of the instructions and values of the function are now
709 // copied over. The only problem is that they are still referencing values in
710 // the Source function as operands. Loop through all of the operands of the
711 // functions and patch them up to point to the local versions...
713 for (Function::iterator BB = Dest->begin(), BE = Dest->end(); BB != BE; ++BB)
714 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
715 for (Instruction::op_iterator OI = I->op_begin(), OE = I->op_end();
717 *OI = RemapOperand(*OI, LocalMap, &GlobalMap);
723 // LinkFunctionBodies - Link in the function bodies that are defined in the
724 // source module into the DestModule. This consists basically of copying the
725 // function over and fixing up references to values.
727 static bool LinkFunctionBodies(Module *Dest, const Module *Src,
728 std::map<const Value*, Value*> &ValueMap,
731 // Loop over all of the functions in the src module, mapping them over as we
734 for (Module::const_iterator SF = Src->begin(), E = Src->end(); SF != E; ++SF){
735 if (!SF->isExternal()) { // No body if function is external
736 Function *DF = cast<Function>(ValueMap[SF]); // Destination function
738 // DF not external SF external?
739 if (DF->isExternal()) {
740 // Only provide the function body if there isn't one already.
741 if (LinkFunctionBody(DF, SF, ValueMap, Err))
749 // LinkAppendingVars - If there were any appending global variables, link them
750 // together now. Return true on error.
752 static bool LinkAppendingVars(Module *M,
753 std::multimap<std::string, GlobalVariable *> &AppendingVars,
754 std::string *ErrorMsg) {
755 if (AppendingVars.empty()) return false; // Nothing to do.
757 // Loop over the multimap of appending vars, processing any variables with the
758 // same name, forming a new appending global variable with both of the
759 // initializers merged together, then rewrite references to the old variables
762 std::vector<Constant*> Inits;
763 while (AppendingVars.size() > 1) {
764 // Get the first two elements in the map...
765 std::multimap<std::string,
766 GlobalVariable*>::iterator Second = AppendingVars.begin(), First=Second++;
768 // If the first two elements are for different names, there is no pair...
769 // Otherwise there is a pair, so link them together...
770 if (First->first == Second->first) {
771 GlobalVariable *G1 = First->second, *G2 = Second->second;
772 const ArrayType *T1 = cast<ArrayType>(G1->getType()->getElementType());
773 const ArrayType *T2 = cast<ArrayType>(G2->getType()->getElementType());
775 // Check to see that they two arrays agree on type...
776 if (T1->getElementType() != T2->getElementType())
777 return Error(ErrorMsg,
778 "Appending variables with different element types need to be linked!");
779 if (G1->isConstant() != G2->isConstant())
780 return Error(ErrorMsg,
781 "Appending variables linked with different const'ness!");
783 unsigned NewSize = T1->getNumElements() + T2->getNumElements();
784 ArrayType *NewType = ArrayType::get(T1->getElementType(), NewSize);
786 // Create the new global variable...
788 new GlobalVariable(NewType, G1->isConstant(), G1->getLinkage(),
789 /*init*/0, First->first, M);
791 // Merge the initializer...
792 Inits.reserve(NewSize);
793 ConstantArray *I = cast<ConstantArray>(G1->getInitializer());
794 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i)
795 Inits.push_back(cast<Constant>(I->getValues()[i]));
796 I = cast<ConstantArray>(G2->getInitializer());
797 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i)
798 Inits.push_back(cast<Constant>(I->getValues()[i]));
799 NG->setInitializer(ConstantArray::get(NewType, Inits));
802 // Replace any uses of the two global variables with uses of the new
805 // FIXME: This should rewrite simple/straight-forward uses such as
806 // getelementptr instructions to not use the Cast!
807 ConstantPointerRef *NGCP = ConstantPointerRef::get(NG);
808 G1->replaceAllUsesWith(ConstantExpr::getCast(NGCP, G1->getType()));
809 G2->replaceAllUsesWith(ConstantExpr::getCast(NGCP, G2->getType()));
811 // Remove the two globals from the module now...
812 M->getGlobalList().erase(G1);
813 M->getGlobalList().erase(G2);
815 // Put the new global into the AppendingVars map so that we can handle
816 // linking of more than two vars...
819 AppendingVars.erase(First);
826 // LinkModules - This function links two modules together, with the resulting
827 // left module modified to be the composite of the two input modules. If an
828 // error occurs, true is returned and ErrorMsg (if not null) is set to indicate
829 // the problem. Upon failure, the Dest module could be in a modified state, and
830 // shouldn't be relied on to be consistent.
832 bool LinkModules(Module *Dest, const Module *Src, std::string *ErrorMsg) {
833 if (Dest->getEndianness() == Module::AnyEndianness)
834 Dest->setEndianness(Src->getEndianness());
835 if (Dest->getPointerSize() == Module::AnyPointerSize)
836 Dest->setPointerSize(Src->getPointerSize());
838 if (Src->getEndianness() != Module::AnyEndianness &&
839 Dest->getEndianness() != Src->getEndianness())
840 std::cerr << "WARNING: Linking two modules of different endianness!\n";
841 if (Src->getPointerSize() != Module::AnyPointerSize &&
842 Dest->getPointerSize() != Src->getPointerSize())
843 std::cerr << "WARNING: Linking two modules of different pointer size!\n";
845 // LinkTypes - Go through the symbol table of the Src module and see if any
846 // types are named in the src module that are not named in the Dst module.
847 // Make sure there are no type name conflicts.
849 if (LinkTypes(Dest, Src, ErrorMsg)) return true;
851 // ValueMap - Mapping of values from what they used to be in Src, to what they
854 std::map<const Value*, Value*> ValueMap;
856 // AppendingVars - Keep track of global variables in the destination module
857 // with appending linkage. After the module is linked together, they are
858 // appended and the module is rewritten.
860 std::multimap<std::string, GlobalVariable *> AppendingVars;
862 // Add all of the appending globals already in the Dest module to
864 for (Module::giterator I = Dest->gbegin(), E = Dest->gend(); I != E; ++I)
865 if (I->hasAppendingLinkage())
866 AppendingVars.insert(std::make_pair(I->getName(), I));
868 // Insert all of the globals in src into the Dest module... without linking
869 // initializers (which could refer to functions not yet mapped over).
871 if (LinkGlobals(Dest, Src, ValueMap, AppendingVars, ErrorMsg)) return true;
873 // Link the functions together between the two modules, without doing function
874 // bodies... this just adds external function prototypes to the Dest
875 // function... We do this so that when we begin processing function bodies,
876 // all of the global values that may be referenced are available in our
879 if (LinkFunctionProtos(Dest, Src, ValueMap, ErrorMsg)) return true;
881 // Update the initializers in the Dest module now that all globals that may
882 // be referenced are in Dest.
884 if (LinkGlobalInits(Dest, Src, ValueMap, ErrorMsg)) return true;
886 // Link in the function bodies that are defined in the source module into the
887 // DestModule. This consists basically of copying the function over and
888 // fixing up references to values.
890 if (LinkFunctionBodies(Dest, Src, ValueMap, ErrorMsg)) return true;
892 // If there were any appending global variables, link them together now.
894 if (LinkAppendingVars(Dest, AppendingVars, ErrorMsg)) return true;