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.
218 // Report the warning and delete one of the names.
219 if (DelayedTypesToResolve.size() == OldSize) {
220 const std::string &Name = DelayedTypesToResolve.back();
222 const Type *T1 = cast<Type>(VM.find(Name)->second);
223 const Type *T2 = cast<Type>(DestST->lookup(Type::TypeTy, Name));
224 std::cerr << "WARNING: Type conflict between types named '" << Name
225 << "'.\n Src='" << *T1 << "'.\n Dest='" << *T2 << "'\n";
227 // Remove the symbol name from the destination.
228 DelayedTypesToResolve.pop_back();
237 static void PrintMap(const std::map<const Value*, Value*> &M) {
238 for (std::map<const Value*, Value*>::const_iterator I = M.begin(), E =M.end();
240 std::cerr << " Fr: " << (void*)I->first << " ";
242 std::cerr << " To: " << (void*)I->second << " ";
249 // RemapOperand - Use LocalMap and GlobalMap to convert references from one
250 // module to another. This is somewhat sophisticated in that it can
251 // automatically handle constant references correctly as well...
253 static Value *RemapOperand(const Value *In,
254 std::map<const Value*, Value*> &LocalMap,
255 std::map<const Value*, Value*> *GlobalMap) {
256 std::map<const Value*,Value*>::const_iterator I = LocalMap.find(In);
257 if (I != LocalMap.end()) return I->second;
260 I = GlobalMap->find(In);
261 if (I != GlobalMap->end()) return I->second;
264 // Check to see if it's a constant that we are interesting in transforming...
265 if (const Constant *CPV = dyn_cast<Constant>(In)) {
266 if (!isa<DerivedType>(CPV->getType()) && !isa<ConstantExpr>(CPV))
267 return const_cast<Constant*>(CPV); // Simple constants stay identical...
269 Constant *Result = 0;
271 if (const ConstantArray *CPA = dyn_cast<ConstantArray>(CPV)) {
272 const std::vector<Use> &Ops = CPA->getValues();
273 std::vector<Constant*> Operands(Ops.size());
274 for (unsigned i = 0, e = Ops.size(); i != e; ++i)
276 cast<Constant>(RemapOperand(Ops[i], LocalMap, GlobalMap));
277 Result = ConstantArray::get(cast<ArrayType>(CPA->getType()), Operands);
278 } else if (const ConstantStruct *CPS = dyn_cast<ConstantStruct>(CPV)) {
279 const std::vector<Use> &Ops = CPS->getValues();
280 std::vector<Constant*> Operands(Ops.size());
281 for (unsigned i = 0; i < Ops.size(); ++i)
283 cast<Constant>(RemapOperand(Ops[i], LocalMap, GlobalMap));
284 Result = ConstantStruct::get(cast<StructType>(CPS->getType()), Operands);
285 } else if (isa<ConstantPointerNull>(CPV)) {
286 Result = const_cast<Constant*>(CPV);
287 } else if (const ConstantPointerRef *CPR =
288 dyn_cast<ConstantPointerRef>(CPV)) {
289 Value *V = RemapOperand(CPR->getValue(), LocalMap, GlobalMap);
290 Result = ConstantPointerRef::get(cast<GlobalValue>(V));
291 } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CPV)) {
292 if (CE->getOpcode() == Instruction::GetElementPtr) {
293 Value *Ptr = RemapOperand(CE->getOperand(0), LocalMap, GlobalMap);
294 std::vector<Constant*> Indices;
295 Indices.reserve(CE->getNumOperands()-1);
296 for (unsigned i = 1, e = CE->getNumOperands(); i != e; ++i)
297 Indices.push_back(cast<Constant>(RemapOperand(CE->getOperand(i),
298 LocalMap, GlobalMap)));
300 Result = ConstantExpr::getGetElementPtr(cast<Constant>(Ptr), Indices);
301 } else if (CE->getNumOperands() == 1) {
303 assert(CE->getOpcode() == Instruction::Cast);
304 Value *V = RemapOperand(CE->getOperand(0), LocalMap, GlobalMap);
305 Result = ConstantExpr::getCast(cast<Constant>(V), CE->getType());
306 } else if (CE->getNumOperands() == 2) {
307 // Binary operator...
308 Value *V1 = RemapOperand(CE->getOperand(0), LocalMap, GlobalMap);
309 Value *V2 = RemapOperand(CE->getOperand(1), LocalMap, GlobalMap);
311 Result = ConstantExpr::get(CE->getOpcode(), cast<Constant>(V1),
314 assert(0 && "Unknown constant expr type!");
318 assert(0 && "Unknown type of derived type constant value!");
321 // Cache the mapping in our local map structure...
323 GlobalMap->insert(std::make_pair(In, Result));
325 LocalMap.insert(std::make_pair(In, Result));
329 std::cerr << "XXX LocalMap: \n";
333 std::cerr << "XXX GlobalMap: \n";
334 PrintMap(*GlobalMap);
337 std::cerr << "Couldn't remap value: " << (void*)In << " " << *In << "\n";
338 assert(0 && "Couldn't remap value!");
342 /// FindGlobalNamed - Look in the specified symbol table for a global with the
343 /// specified name and type. If an exactly matching global does not exist, see
344 /// if there is a global which is "type compatible" with the specified
345 /// name/type. This allows us to resolve things like '%x = global int*' with
346 /// '%x = global opaque*'.
348 static GlobalValue *FindGlobalNamed(const std::string &Name, const Type *Ty,
350 // See if an exact match exists in the symbol table...
351 if (Value *V = ST->lookup(Ty, Name)) return cast<GlobalValue>(V);
353 // It doesn't exist exactly, scan through all of the type planes in the symbol
354 // table, checking each of them for a type-compatible version.
356 for (SymbolTable::iterator I = ST->begin(), E = ST->end(); I != E; ++I)
357 if (I->first != Type::TypeTy) {
358 SymbolTable::VarMap &VM = I->second;
359 // Does this type plane contain an entry with the specified name?
360 SymbolTable::type_iterator TI = VM.find(Name);
361 if (TI != VM.end()) {
362 // Determine whether we can fold the two types together, resolving them.
363 // If so, we can use this value.
364 if (!RecursiveResolveTypes(Ty, I->first, ST, ""))
365 return cast<GlobalValue>(TI->second);
368 return 0; // Otherwise, nothing could be found.
372 // LinkGlobals - Loop through the global variables in the src module and merge
373 // them into the dest module.
375 static bool LinkGlobals(Module *Dest, const Module *Src,
376 std::map<const Value*, Value*> &ValueMap,
377 std::multimap<std::string, GlobalVariable *> &AppendingVars,
379 // We will need a module level symbol table if the src module has a module
380 // level symbol table...
381 SymbolTable *ST = (SymbolTable*)&Dest->getSymbolTable();
383 // Loop over all of the globals in the src module, mapping them over as we go
385 for (Module::const_giterator I = Src->gbegin(), E = Src->gend(); I != E; ++I){
386 const GlobalVariable *SGV = I;
387 GlobalVariable *DGV = 0;
388 if (SGV->hasName()) {
389 // A same named thing is a global variable, because the only two things
390 // that may be in a module level symbol table are Global Vars and
391 // Functions, and they both have distinct, nonoverlapping, possible types.
393 DGV = cast_or_null<GlobalVariable>(FindGlobalNamed(SGV->getName(),
394 SGV->getType(), ST));
397 assert(SGV->hasInitializer() || SGV->hasExternalLinkage() &&
398 "Global must either be external or have an initializer!");
400 bool SGExtern = SGV->isExternal();
401 bool DGExtern = DGV ? DGV->isExternal() : false;
403 if (!DGV || DGV->hasInternalLinkage() || SGV->hasInternalLinkage()) {
404 // No linking to be performed, simply create an identical version of the
405 // symbol over in the dest module... the initializer will be filled in
406 // later by LinkGlobalInits...
408 GlobalVariable *NewDGV =
409 new GlobalVariable(SGV->getType()->getElementType(),
410 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
411 SGV->getName(), Dest);
413 // If the LLVM runtime renamed the global, but it is an externally visible
414 // symbol, DGV must be an existing global with internal linkage. Rename
416 if (NewDGV->getName() != SGV->getName() && !NewDGV->hasInternalLinkage()){
417 assert(DGV && DGV->getName() == SGV->getName() &&
418 DGV->hasInternalLinkage());
420 NewDGV->setName(SGV->getName()); // Force the name back
421 DGV->setName(SGV->getName()); // This will cause a renaming
422 assert(NewDGV->getName() == SGV->getName() &&
423 DGV->getName() != SGV->getName());
426 // Make sure to remember this mapping...
427 ValueMap.insert(std::make_pair(SGV, NewDGV));
428 if (SGV->hasAppendingLinkage())
429 // Keep track that this is an appending variable...
430 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV));
432 } else if (SGV->isExternal()) {
433 // If SGV is external or if both SGV & DGV are external.. Just link the
434 // external globals, we aren't adding anything.
435 ValueMap.insert(std::make_pair(SGV, DGV));
437 } else if (DGV->isExternal()) { // If DGV is external but SGV is not...
438 ValueMap.insert(std::make_pair(SGV, DGV));
439 DGV->setLinkage(SGV->getLinkage()); // Inherit linkage!
440 } else if (SGV->hasWeakLinkage() || SGV->hasLinkOnceLinkage()) {
441 // At this point we know that DGV has LinkOnce, Appending, Weak, or
442 // External linkage. If DGV is Appending, this is an error.
443 if (DGV->hasAppendingLinkage())
444 return Error(Err, "Linking globals named '" + SGV->getName() +
445 " ' with 'weak' and 'appending' linkage is not allowed!");
447 if (SGV->isConstant() != DGV->isConstant())
448 return Error(Err, "Global Variable Collision on '" +
449 SGV->getType()->getDescription() + " %" + SGV->getName() +
450 "' - Global variables differ in const'ness");
452 // Otherwise, just perform the link.
453 ValueMap.insert(std::make_pair(SGV, DGV));
455 // Linkonce+Weak = Weak
456 if (DGV->hasLinkOnceLinkage() && SGV->hasWeakLinkage())
457 DGV->setLinkage(SGV->getLinkage());
459 } else if (DGV->hasWeakLinkage() || DGV->hasLinkOnceLinkage()) {
460 // At this point we know that SGV has LinkOnce, Appending, or External
461 // linkage. If SGV is Appending, this is an error.
462 if (SGV->hasAppendingLinkage())
463 return Error(Err, "Linking globals named '" + SGV->getName() +
464 " ' with 'weak' and 'appending' linkage is not allowed!");
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->hasLinkOnceLinkage())
472 DGV->setLinkage(SGV->getLinkage()); // Inherit linkage!
473 ValueMap.insert(std::make_pair(SGV, DGV));
475 } else if (SGV->getLinkage() != DGV->getLinkage()) {
476 return Error(Err, "Global variables named '" + SGV->getName() +
477 "' have different linkage specifiers!");
478 } else if (SGV->hasExternalLinkage()) {
479 // Allow linking two exactly identical external global variables...
480 if (SGV->isConstant() != DGV->isConstant())
481 return Error(Err, "Global Variable Collision on '" +
482 SGV->getType()->getDescription() + " %" + SGV->getName() +
483 "' - Global variables differ in const'ness");
485 if (SGV->getInitializer() != DGV->getInitializer())
486 return Error(Err, "Global Variable Collision on '" +
487 SGV->getType()->getDescription() + " %" + SGV->getName() +
488 "' - External linkage globals have different initializers");
490 ValueMap.insert(std::make_pair(SGV, DGV));
491 } else if (SGV->hasAppendingLinkage()) {
492 // No linking is performed yet. Just insert a new copy of the global, and
493 // keep track of the fact that it is an appending variable in the
494 // AppendingVars map. The name is cleared out so that no linkage is
496 GlobalVariable *NewDGV =
497 new GlobalVariable(SGV->getType()->getElementType(),
498 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
501 // Make sure to remember this mapping...
502 ValueMap.insert(std::make_pair(SGV, NewDGV));
504 // Keep track that this is an appending variable...
505 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV));
507 assert(0 && "Unknown linkage!");
514 // LinkGlobalInits - Update the initializers in the Dest module now that all
515 // globals that may be referenced are in Dest.
517 static bool LinkGlobalInits(Module *Dest, const Module *Src,
518 std::map<const Value*, Value*> &ValueMap,
521 // Loop over all of the globals in the src module, mapping them over as we go
523 for (Module::const_giterator I = Src->gbegin(), E = Src->gend(); I != E; ++I){
524 const GlobalVariable *SGV = I;
526 if (SGV->hasInitializer()) { // Only process initialized GV's
527 // Figure out what the initializer looks like in the dest module...
529 cast<Constant>(RemapOperand(SGV->getInitializer(), ValueMap, 0));
531 GlobalVariable *DGV = cast<GlobalVariable>(ValueMap[SGV]);
532 if (DGV->hasInitializer()) {
533 assert(SGV->getLinkage() == DGV->getLinkage());
534 if (SGV->hasExternalLinkage()) {
535 if (DGV->getInitializer() != SInit)
536 return Error(Err, "Global Variable Collision on '" +
537 SGV->getType()->getDescription() +"':%"+SGV->getName()+
538 " - Global variables have different initializers");
539 } else if (DGV->hasLinkOnceLinkage() || DGV->hasWeakLinkage()) {
540 // Nothing is required, mapped values will take the new global
542 } else if (DGV->hasAppendingLinkage()) {
543 assert(0 && "Appending linkage unimplemented!");
545 assert(0 && "Unknown linkage!");
548 // Copy the initializer over now...
549 DGV->setInitializer(SInit);
556 // LinkFunctionProtos - Link the functions together between the two modules,
557 // without doing function bodies... this just adds external function prototypes
558 // to the Dest function...
560 static bool LinkFunctionProtos(Module *Dest, const Module *Src,
561 std::map<const Value*, Value*> &ValueMap,
563 SymbolTable *ST = (SymbolTable*)&Dest->getSymbolTable();
565 // Loop over all of the functions in the src module, mapping them over as we
568 for (Module::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) {
569 const Function *SF = I; // SrcFunction
572 // The same named thing is a Function, because the only two things
573 // that may be in a module level symbol table are Global Vars and
574 // Functions, and they both have distinct, nonoverlapping, possible types.
576 DF = cast_or_null<Function>(FindGlobalNamed(SF->getName(), SF->getType(),
579 if (!DF || SF->hasInternalLinkage() || DF->hasInternalLinkage()) {
580 // Function does not already exist, simply insert an function signature
581 // identical to SF into the dest module...
582 Function *NewDF = new Function(SF->getFunctionType(), SF->getLinkage(),
583 SF->getName(), Dest);
585 // If the LLVM runtime renamed the function, but it is an externally
586 // visible symbol, DF must be an existing function with internal linkage.
588 if (NewDF->getName() != SF->getName() && !NewDF->hasInternalLinkage()) {
589 assert(DF && DF->getName() == SF->getName() &&DF->hasInternalLinkage());
591 NewDF->setName(SF->getName()); // Force the name back
592 DF->setName(SF->getName()); // This will cause a renaming
593 assert(NewDF->getName() == SF->getName() &&
594 DF->getName() != SF->getName());
597 // ... and remember this mapping...
598 ValueMap.insert(std::make_pair(SF, NewDF));
599 } else if (SF->isExternal()) {
600 // If SF is external or if both SF & DF are external.. Just link the
601 // external functions, we aren't adding anything.
602 ValueMap.insert(std::make_pair(SF, DF));
603 } else if (DF->isExternal()) { // If DF is external but SF is not...
604 // Link the external functions, update linkage qualifiers
605 ValueMap.insert(std::make_pair(SF, DF));
606 DF->setLinkage(SF->getLinkage());
608 } else if (SF->hasWeakLinkage() || SF->hasLinkOnceLinkage()) {
609 // At this point we know that DF has LinkOnce, Weak, or External linkage.
610 ValueMap.insert(std::make_pair(SF, DF));
612 // Linkonce+Weak = Weak
613 if (DF->hasLinkOnceLinkage() && SF->hasWeakLinkage())
614 DF->setLinkage(SF->getLinkage());
616 } else if (DF->hasWeakLinkage() || DF->hasLinkOnceLinkage()) {
617 // At this point we know that SF has LinkOnce or External linkage.
618 ValueMap.insert(std::make_pair(SF, DF));
619 if (!SF->hasLinkOnceLinkage()) // Don't inherit linkonce linkage
620 DF->setLinkage(SF->getLinkage());
622 } else if (SF->getLinkage() != DF->getLinkage()) {
623 return Error(Err, "Functions named '" + SF->getName() +
624 "' have different linkage specifiers!");
625 } else if (SF->hasExternalLinkage()) {
626 // The function is defined in both modules!!
627 return Error(Err, "Function '" +
628 SF->getFunctionType()->getDescription() + "':\"" +
629 SF->getName() + "\" - Function is already defined!");
631 assert(0 && "Unknown linkage configuration found!");
637 // LinkFunctionBody - Copy the source function over into the dest function and
638 // fix up references to values. At this point we know that Dest is an external
639 // function, and that Src is not.
641 static bool LinkFunctionBody(Function *Dest, const Function *Src,
642 std::map<const Value*, Value*> &GlobalMap,
644 assert(Src && Dest && Dest->isExternal() && !Src->isExternal());
645 std::map<const Value*, Value*> LocalMap; // Map for function local values
647 // Go through and convert function arguments over...
648 Function::aiterator DI = Dest->abegin();
649 for (Function::const_aiterator I = Src->abegin(), E = Src->aend();
651 DI->setName(I->getName()); // Copy the name information over...
653 // Add a mapping to our local map
654 LocalMap.insert(std::make_pair(I, DI));
657 // Loop over all of the basic blocks, copying the instructions over...
659 for (Function::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) {
660 // Create new basic block and add to mapping and the Dest function...
661 BasicBlock *DBB = new BasicBlock(I->getName(), Dest);
662 LocalMap.insert(std::make_pair(I, DBB));
664 // Loop over all of the instructions in the src basic block, copying them
665 // over. Note that this is broken in a strict sense because the cloned
666 // instructions will still be referencing values in the Src module, not
667 // the remapped values. In our case, however, we will not get caught and
668 // so we can delay patching the values up until later...
670 for (BasicBlock::const_iterator II = I->begin(), IE = I->end();
672 Instruction *DI = II->clone();
673 DI->setName(II->getName());
674 DBB->getInstList().push_back(DI);
675 LocalMap.insert(std::make_pair(II, DI));
679 // At this point, all of the instructions and values of the function are now
680 // copied over. The only problem is that they are still referencing values in
681 // the Source function as operands. Loop through all of the operands of the
682 // functions and patch them up to point to the local versions...
684 for (Function::iterator BB = Dest->begin(), BE = Dest->end(); BB != BE; ++BB)
685 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
686 for (Instruction::op_iterator OI = I->op_begin(), OE = I->op_end();
688 *OI = RemapOperand(*OI, LocalMap, &GlobalMap);
694 // LinkFunctionBodies - Link in the function bodies that are defined in the
695 // source module into the DestModule. This consists basically of copying the
696 // function over and fixing up references to values.
698 static bool LinkFunctionBodies(Module *Dest, const Module *Src,
699 std::map<const Value*, Value*> &ValueMap,
702 // Loop over all of the functions in the src module, mapping them over as we
705 for (Module::const_iterator SF = Src->begin(), E = Src->end(); SF != E; ++SF){
706 if (!SF->isExternal()) { // No body if function is external
707 Function *DF = cast<Function>(ValueMap[SF]); // Destination function
709 // DF not external SF external?
710 if (DF->isExternal()) {
711 // Only provide the function body if there isn't one already.
712 if (LinkFunctionBody(DF, SF, ValueMap, Err))
720 // LinkAppendingVars - If there were any appending global variables, link them
721 // together now. Return true on error.
723 static bool LinkAppendingVars(Module *M,
724 std::multimap<std::string, GlobalVariable *> &AppendingVars,
725 std::string *ErrorMsg) {
726 if (AppendingVars.empty()) return false; // Nothing to do.
728 // Loop over the multimap of appending vars, processing any variables with the
729 // same name, forming a new appending global variable with both of the
730 // initializers merged together, then rewrite references to the old variables
733 std::vector<Constant*> Inits;
734 while (AppendingVars.size() > 1) {
735 // Get the first two elements in the map...
736 std::multimap<std::string,
737 GlobalVariable*>::iterator Second = AppendingVars.begin(), First=Second++;
739 // If the first two elements are for different names, there is no pair...
740 // Otherwise there is a pair, so link them together...
741 if (First->first == Second->first) {
742 GlobalVariable *G1 = First->second, *G2 = Second->second;
743 const ArrayType *T1 = cast<ArrayType>(G1->getType()->getElementType());
744 const ArrayType *T2 = cast<ArrayType>(G2->getType()->getElementType());
746 // Check to see that they two arrays agree on type...
747 if (T1->getElementType() != T2->getElementType())
748 return Error(ErrorMsg,
749 "Appending variables with different element types need to be linked!");
750 if (G1->isConstant() != G2->isConstant())
751 return Error(ErrorMsg,
752 "Appending variables linked with different const'ness!");
754 unsigned NewSize = T1->getNumElements() + T2->getNumElements();
755 ArrayType *NewType = ArrayType::get(T1->getElementType(), NewSize);
757 // Create the new global variable...
759 new GlobalVariable(NewType, G1->isConstant(), G1->getLinkage(),
760 /*init*/0, First->first, M);
762 // Merge the initializer...
763 Inits.reserve(NewSize);
764 ConstantArray *I = cast<ConstantArray>(G1->getInitializer());
765 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i)
766 Inits.push_back(cast<Constant>(I->getValues()[i]));
767 I = cast<ConstantArray>(G2->getInitializer());
768 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i)
769 Inits.push_back(cast<Constant>(I->getValues()[i]));
770 NG->setInitializer(ConstantArray::get(NewType, Inits));
773 // Replace any uses of the two global variables with uses of the new
776 // FIXME: This should rewrite simple/straight-forward uses such as
777 // getelementptr instructions to not use the Cast!
778 ConstantPointerRef *NGCP = ConstantPointerRef::get(NG);
779 G1->replaceAllUsesWith(ConstantExpr::getCast(NGCP, G1->getType()));
780 G2->replaceAllUsesWith(ConstantExpr::getCast(NGCP, G2->getType()));
782 // Remove the two globals from the module now...
783 M->getGlobalList().erase(G1);
784 M->getGlobalList().erase(G2);
786 // Put the new global into the AppendingVars map so that we can handle
787 // linking of more than two vars...
790 AppendingVars.erase(First);
797 // LinkModules - This function links two modules together, with the resulting
798 // left module modified to be the composite of the two input modules. If an
799 // error occurs, true is returned and ErrorMsg (if not null) is set to indicate
800 // the problem. Upon failure, the Dest module could be in a modified state, and
801 // shouldn't be relied on to be consistent.
803 bool LinkModules(Module *Dest, const Module *Src, std::string *ErrorMsg) {
804 if (Dest->getEndianness() == Module::AnyEndianness)
805 Dest->setEndianness(Src->getEndianness());
806 if (Dest->getPointerSize() == Module::AnyPointerSize)
807 Dest->setPointerSize(Src->getPointerSize());
809 if (Src->getEndianness() != Module::AnyEndianness &&
810 Dest->getEndianness() != Src->getEndianness())
811 std::cerr << "WARNING: Linking two modules of different endianness!\n";
812 if (Src->getPointerSize() != Module::AnyPointerSize &&
813 Dest->getPointerSize() != Src->getPointerSize())
814 std::cerr << "WARNING: Linking two modules of different pointer size!\n";
816 // LinkTypes - Go through the symbol table of the Src module and see if any
817 // types are named in the src module that are not named in the Dst module.
818 // Make sure there are no type name conflicts.
820 if (LinkTypes(Dest, Src, ErrorMsg)) return true;
822 // ValueMap - Mapping of values from what they used to be in Src, to what they
825 std::map<const Value*, Value*> ValueMap;
827 // AppendingVars - Keep track of global variables in the destination module
828 // with appending linkage. After the module is linked together, they are
829 // appended and the module is rewritten.
831 std::multimap<std::string, GlobalVariable *> AppendingVars;
833 // Add all of the appending globals already in the Dest module to
835 for (Module::giterator I = Dest->gbegin(), E = Dest->gend(); I != E; ++I)
836 if (I->hasAppendingLinkage())
837 AppendingVars.insert(std::make_pair(I->getName(), I));
839 // Insert all of the globals in src into the Dest module... without linking
840 // initializers (which could refer to functions not yet mapped over).
842 if (LinkGlobals(Dest, Src, ValueMap, AppendingVars, ErrorMsg)) return true;
844 // Link the functions together between the two modules, without doing function
845 // bodies... this just adds external function prototypes to the Dest
846 // function... We do this so that when we begin processing function bodies,
847 // all of the global values that may be referenced are available in our
850 if (LinkFunctionProtos(Dest, Src, ValueMap, ErrorMsg)) return true;
852 // Update the initializers in the Dest module now that all globals that may
853 // be referenced are in Dest.
855 if (LinkGlobalInits(Dest, Src, ValueMap, ErrorMsg)) return true;
857 // Link in the function bodies that are defined in the source module into the
858 // DestModule. This consists basically of copying the function over and
859 // fixing up references to values.
861 if (LinkFunctionBodies(Dest, Src, ValueMap, ErrorMsg)) return true;
863 // If there were any appending global variables, link them together now.
865 if (LinkAppendingVars(Dest, AppendingVars, ErrorMsg)) return true;