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/Constants.h"
21 #include "llvm/DerivedTypes.h"
22 #include "llvm/Module.h"
23 #include "llvm/SymbolTable.h"
24 #include "llvm/iOther.h"
25 #include "llvm/Assembly/Writer.h"
29 // Error - Simple wrapper function to conditionally assign to E and return true.
30 // This just makes error return conditions a little bit simpler...
32 static inline bool Error(std::string *E, const std::string &Message) {
38 // Function: ResolveTypes()
41 // Attempt to link the two specified types together.
44 // DestTy - The type to which we wish to resolve.
45 // SrcTy - The original type which we want to resolve.
46 // Name - The name of the type.
49 // DestST - The symbol table in which the new type should be placed.
52 // true - There is an error and the types cannot yet be linked.
55 static bool ResolveTypes(const Type *DestTy, const Type *SrcTy,
56 SymbolTable *DestST, const std::string &Name) {
57 if (DestTy == SrcTy) return false; // If already equal, noop
59 // Does the type already exist in the module?
60 if (DestTy && !isa<OpaqueType>(DestTy)) { // Yup, the type already exists...
61 if (const OpaqueType *OT = dyn_cast<OpaqueType>(SrcTy)) {
62 const_cast<OpaqueType*>(OT)->refineAbstractTypeTo(DestTy);
64 return true; // Cannot link types... neither is opaque and not-equal
66 } else { // Type not in dest module. Add it now.
67 if (DestTy) // Type _is_ in module, just opaque...
68 const_cast<OpaqueType*>(cast<OpaqueType>(DestTy))
69 ->refineAbstractTypeTo(SrcTy);
70 else if (!Name.empty())
71 DestST->insert(Name, const_cast<Type*>(SrcTy));
76 static const FunctionType *getFT(const PATypeHolder &TH) {
77 return cast<FunctionType>(TH.get());
79 static const StructType *getST(const PATypeHolder &TH) {
80 return cast<StructType>(TH.get());
83 // RecursiveResolveTypes - This is just like ResolveTypes, except that it
84 // recurses down into derived types, merging the used types if the parent types
87 static bool RecursiveResolveTypesI(const PATypeHolder &DestTy,
88 const PATypeHolder &SrcTy,
89 SymbolTable *DestST, const std::string &Name,
90 std::vector<std::pair<PATypeHolder, PATypeHolder> > &Pointers) {
91 const Type *SrcTyT = SrcTy.get();
92 const Type *DestTyT = DestTy.get();
93 if (DestTyT == SrcTyT) return false; // If already equal, noop
95 // If we found our opaque type, resolve it now!
96 if (isa<OpaqueType>(DestTyT) || isa<OpaqueType>(SrcTyT))
97 return ResolveTypes(DestTyT, SrcTyT, DestST, Name);
99 // Two types cannot be resolved together if they are of different primitive
100 // type. For example, we cannot resolve an int to a float.
101 if (DestTyT->getPrimitiveID() != SrcTyT->getPrimitiveID()) return true;
103 // Otherwise, resolve the used type used by this derived type...
104 switch (DestTyT->getPrimitiveID()) {
105 case Type::FunctionTyID: {
106 if (cast<FunctionType>(DestTyT)->isVarArg() !=
107 cast<FunctionType>(SrcTyT)->isVarArg() ||
108 cast<FunctionType>(DestTyT)->getNumContainedTypes() !=
109 cast<FunctionType>(SrcTyT)->getNumContainedTypes())
111 for (unsigned i = 0, e = getFT(DestTy)->getNumContainedTypes(); i != e; ++i)
112 if (RecursiveResolveTypesI(getFT(DestTy)->getContainedType(i),
113 getFT(SrcTy)->getContainedType(i), DestST, "",
118 case Type::StructTyID: {
119 if (getST(DestTy)->getNumContainedTypes() !=
120 getST(SrcTy)->getNumContainedTypes()) return 1;
121 for (unsigned i = 0, e = getST(DestTy)->getNumContainedTypes(); i != e; ++i)
122 if (RecursiveResolveTypesI(getST(DestTy)->getContainedType(i),
123 getST(SrcTy)->getContainedType(i), DestST, "",
128 case Type::ArrayTyID: {
129 const ArrayType *DAT = cast<ArrayType>(DestTy.get());
130 const ArrayType *SAT = cast<ArrayType>(SrcTy.get());
131 if (DAT->getNumElements() != SAT->getNumElements()) return true;
132 return RecursiveResolveTypesI(DAT->getElementType(), SAT->getElementType(),
133 DestST, "", Pointers);
135 case Type::PointerTyID: {
136 // If this is a pointer type, check to see if we have already seen it. If
137 // so, we are in a recursive branch. Cut off the search now. We cannot use
138 // an associative container for this search, because the type pointers (keys
139 // in the container) change whenever types get resolved...
141 for (unsigned i = 0, e = Pointers.size(); i != e; ++i)
142 if (Pointers[i].first == DestTy)
143 return Pointers[i].second != SrcTy;
145 // Otherwise, add the current pointers to the vector to stop recursion on
147 Pointers.push_back(std::make_pair(DestTyT, SrcTyT));
149 RecursiveResolveTypesI(cast<PointerType>(DestTy.get())->getElementType(),
150 cast<PointerType>(SrcTy.get())->getElementType(),
151 DestST, "", Pointers);
155 default: assert(0 && "Unexpected type!"); return true;
159 static bool RecursiveResolveTypes(const PATypeHolder &DestTy,
160 const PATypeHolder &SrcTy,
161 SymbolTable *DestST, const std::string &Name){
162 std::vector<std::pair<PATypeHolder, PATypeHolder> > PointerTypes;
163 return RecursiveResolveTypesI(DestTy, SrcTy, DestST, Name, PointerTypes);
167 // LinkTypes - Go through the symbol table of the Src module and see if any
168 // types are named in the src module that are not named in the Dst module.
169 // Make sure there are no type name conflicts.
171 static bool LinkTypes(Module *Dest, const Module *Src, std::string *Err) {
172 SymbolTable *DestST = &Dest->getSymbolTable();
173 const SymbolTable *SrcST = &Src->getSymbolTable();
175 // Look for a type plane for Type's...
176 SymbolTable::const_iterator PI = SrcST->find(Type::TypeTy);
177 if (PI == SrcST->end()) return false; // No named types, do nothing.
179 // Some types cannot be resolved immediately because they depend on other
180 // types being resolved to each other first. This contains a list of types we
181 // are waiting to recheck.
182 std::vector<std::string> DelayedTypesToResolve;
184 const SymbolTable::VarMap &VM = PI->second;
185 for (SymbolTable::type_const_iterator I = VM.begin(), E = VM.end();
187 const std::string &Name = I->first;
188 Type *RHS = cast<Type>(I->second);
190 // Check to see if this type name is already in the dest module...
191 Type *Entry = cast_or_null<Type>(DestST->lookup(Type::TypeTy, Name));
193 if (ResolveTypes(Entry, RHS, DestST, Name)) {
194 // They look different, save the types 'till later to resolve.
195 DelayedTypesToResolve.push_back(Name);
199 // Iteratively resolve types while we can...
200 while (!DelayedTypesToResolve.empty()) {
201 // Loop over all of the types, attempting to resolve them if possible...
202 unsigned OldSize = DelayedTypesToResolve.size();
204 // Try direct resolution by name...
205 for (unsigned i = 0; i != DelayedTypesToResolve.size(); ++i) {
206 const std::string &Name = DelayedTypesToResolve[i];
207 Type *T1 = cast<Type>(VM.find(Name)->second);
208 Type *T2 = cast<Type>(DestST->lookup(Type::TypeTy, Name));
209 if (!ResolveTypes(T2, T1, DestST, Name)) {
210 // We are making progress!
211 DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i);
216 // Did we not eliminate any types?
217 if (DelayedTypesToResolve.size() == OldSize) {
218 // Attempt to resolve subelements of types. This allows us to merge these
219 // two types: { int* } and { opaque* }
220 for (unsigned i = 0, e = DelayedTypesToResolve.size(); i != e; ++i) {
221 const std::string &Name = DelayedTypesToResolve[i];
222 PATypeHolder T1(cast<Type>(VM.find(Name)->second));
223 PATypeHolder T2(cast<Type>(DestST->lookup(Type::TypeTy, Name)));
225 if (!RecursiveResolveTypes(T2, T1, DestST, Name)) {
226 // We are making progress!
227 DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i);
229 // Go back to the main loop, perhaps we can resolve directly by name
235 // If we STILL cannot resolve the types, then there is something wrong.
236 // Report the warning and delete one of the names.
237 if (DelayedTypesToResolve.size() == OldSize) {
238 const std::string &Name = DelayedTypesToResolve.back();
240 const Type *T1 = cast<Type>(VM.find(Name)->second);
241 const Type *T2 = cast<Type>(DestST->lookup(Type::TypeTy, Name));
242 std::cerr << "WARNING: Type conflict between types named '" << Name
244 WriteTypeSymbolic(std::cerr, T1, Src);
245 std::cerr << "'.\n Dest='";
246 WriteTypeSymbolic(std::cerr, T2, Dest);
249 // Remove the symbol name from the destination.
250 DelayedTypesToResolve.pop_back();
259 static void PrintMap(const std::map<const Value*, Value*> &M) {
260 for (std::map<const Value*, Value*>::const_iterator I = M.begin(), E =M.end();
262 std::cerr << " Fr: " << (void*)I->first << " ";
264 std::cerr << " To: " << (void*)I->second << " ";
271 // RemapOperand - Use LocalMap and GlobalMap to convert references from one
272 // module to another. This is somewhat sophisticated in that it can
273 // automatically handle constant references correctly as well...
275 static Value *RemapOperand(const Value *In,
276 std::map<const Value*, Value*> &LocalMap,
277 std::map<const Value*, Value*> *GlobalMap) {
278 std::map<const Value*,Value*>::const_iterator I = LocalMap.find(In);
279 if (I != LocalMap.end()) return I->second;
282 I = GlobalMap->find(In);
283 if (I != GlobalMap->end()) return I->second;
286 // Check to see if it's a constant that we are interesting in transforming...
287 if (const Constant *CPV = dyn_cast<Constant>(In)) {
288 if (!isa<DerivedType>(CPV->getType()) && !isa<ConstantExpr>(CPV))
289 return const_cast<Constant*>(CPV); // Simple constants stay identical...
291 Constant *Result = 0;
293 if (const ConstantArray *CPA = dyn_cast<ConstantArray>(CPV)) {
294 const std::vector<Use> &Ops = CPA->getValues();
295 std::vector<Constant*> Operands(Ops.size());
296 for (unsigned i = 0, e = Ops.size(); i != e; ++i)
298 cast<Constant>(RemapOperand(Ops[i], LocalMap, GlobalMap));
299 Result = ConstantArray::get(cast<ArrayType>(CPA->getType()), Operands);
300 } else if (const ConstantStruct *CPS = dyn_cast<ConstantStruct>(CPV)) {
301 const std::vector<Use> &Ops = CPS->getValues();
302 std::vector<Constant*> Operands(Ops.size());
303 for (unsigned i = 0; i < Ops.size(); ++i)
305 cast<Constant>(RemapOperand(Ops[i], LocalMap, GlobalMap));
306 Result = ConstantStruct::get(cast<StructType>(CPS->getType()), Operands);
307 } else if (isa<ConstantPointerNull>(CPV)) {
308 Result = const_cast<Constant*>(CPV);
309 } else if (const ConstantPointerRef *CPR =
310 dyn_cast<ConstantPointerRef>(CPV)) {
311 Value *V = RemapOperand(CPR->getValue(), LocalMap, GlobalMap);
312 Result = ConstantPointerRef::get(cast<GlobalValue>(V));
313 } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CPV)) {
314 if (CE->getOpcode() == Instruction::GetElementPtr) {
315 Value *Ptr = RemapOperand(CE->getOperand(0), LocalMap, GlobalMap);
316 std::vector<Constant*> Indices;
317 Indices.reserve(CE->getNumOperands()-1);
318 for (unsigned i = 1, e = CE->getNumOperands(); i != e; ++i)
319 Indices.push_back(cast<Constant>(RemapOperand(CE->getOperand(i),
320 LocalMap, GlobalMap)));
322 Result = ConstantExpr::getGetElementPtr(cast<Constant>(Ptr), Indices);
323 } else if (CE->getNumOperands() == 1) {
325 assert(CE->getOpcode() == Instruction::Cast);
326 Value *V = RemapOperand(CE->getOperand(0), LocalMap, GlobalMap);
327 Result = ConstantExpr::getCast(cast<Constant>(V), CE->getType());
328 } else if (CE->getOpcode() == Instruction::Shl ||
329 CE->getOpcode() == Instruction::Shr) { // Shift
330 Value *V1 = RemapOperand(CE->getOperand(0), LocalMap, GlobalMap);
331 Value *V2 = RemapOperand(CE->getOperand(1), LocalMap, GlobalMap);
332 Result = ConstantExpr::getShift(CE->getOpcode(), cast<Constant>(V1),
334 } else if (CE->getNumOperands() == 2) {
335 // Binary operator...
336 Value *V1 = RemapOperand(CE->getOperand(0), LocalMap, GlobalMap);
337 Value *V2 = RemapOperand(CE->getOperand(1), LocalMap, GlobalMap);
339 Result = ConstantExpr::get(CE->getOpcode(), cast<Constant>(V1),
342 assert(0 && "Unknown constant expr type!");
346 assert(0 && "Unknown type of derived type constant value!");
349 // Cache the mapping in our local map structure...
351 GlobalMap->insert(std::make_pair(In, Result));
353 LocalMap.insert(std::make_pair(In, Result));
357 std::cerr << "XXX LocalMap: \n";
361 std::cerr << "XXX GlobalMap: \n";
362 PrintMap(*GlobalMap);
365 std::cerr << "Couldn't remap value: " << (void*)In << " " << *In << "\n";
366 assert(0 && "Couldn't remap value!");
370 /// FindGlobalNamed - Look in the specified symbol table for a global with the
371 /// specified name and type. If an exactly matching global does not exist, see
372 /// if there is a global which is "type compatible" with the specified
373 /// name/type. This allows us to resolve things like '%x = global int*' with
374 /// '%x = global opaque*'.
376 static GlobalValue *FindGlobalNamed(const std::string &Name, const Type *Ty,
378 // See if an exact match exists in the symbol table...
379 if (Value *V = ST->lookup(Ty, Name)) return cast<GlobalValue>(V);
381 // It doesn't exist exactly, scan through all of the type planes in the symbol
382 // table, checking each of them for a type-compatible version.
384 for (SymbolTable::iterator I = ST->begin(), E = ST->end(); I != E; ++I)
385 if (I->first != Type::TypeTy) {
386 SymbolTable::VarMap &VM = I->second;
388 // Does this type plane contain an entry with the specified name?
389 SymbolTable::type_iterator TI = VM.find(Name);
390 if (TI != VM.end()) {
392 // Ensure that this type if placed correctly into the symbol table.
394 assert(TI->second->getType() == I->first && "Type conflict!");
397 // Save a reference to the new type. Resolving the type can modify the
398 // symbol table, invalidating the TI variable.
400 Value *ValPtr = TI->second;
403 // Determine whether we can fold the two types together, resolving them.
404 // If so, we can use this value.
406 if (!RecursiveResolveTypes(Ty, I->first, ST, ""))
407 return cast<GlobalValue>(ValPtr);
410 return 0; // Otherwise, nothing could be found.
414 // LinkGlobals - Loop through the global variables in the src module and merge
415 // them into the dest module.
417 static bool LinkGlobals(Module *Dest, const Module *Src,
418 std::map<const Value*, Value*> &ValueMap,
419 std::multimap<std::string, GlobalVariable *> &AppendingVars,
421 // We will need a module level symbol table if the src module has a module
422 // level symbol table...
423 SymbolTable *ST = (SymbolTable*)&Dest->getSymbolTable();
425 // Loop over all of the globals in the src module, mapping them over as we go
427 for (Module::const_giterator I = Src->gbegin(), E = Src->gend(); I != E; ++I){
428 const GlobalVariable *SGV = I;
429 GlobalVariable *DGV = 0;
430 if (SGV->hasName()) {
431 // A same named thing is a global variable, because the only two things
432 // that may be in a module level symbol table are Global Vars and
433 // Functions, and they both have distinct, nonoverlapping, possible types.
435 DGV = cast_or_null<GlobalVariable>(FindGlobalNamed(SGV->getName(),
436 SGV->getType(), ST));
439 assert(SGV->hasInitializer() || SGV->hasExternalLinkage() &&
440 "Global must either be external or have an initializer!");
442 bool SGExtern = SGV->isExternal();
443 bool DGExtern = DGV ? DGV->isExternal() : false;
445 if (!DGV || DGV->hasInternalLinkage() || SGV->hasInternalLinkage()) {
446 // No linking to be performed, simply create an identical version of the
447 // symbol over in the dest module... the initializer will be filled in
448 // later by LinkGlobalInits...
450 GlobalVariable *NewDGV =
451 new GlobalVariable(SGV->getType()->getElementType(),
452 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
453 SGV->getName(), Dest);
455 // If the LLVM runtime renamed the global, but it is an externally visible
456 // symbol, DGV must be an existing global with internal linkage. Rename
458 if (NewDGV->getName() != SGV->getName() && !NewDGV->hasInternalLinkage()){
459 assert(DGV && DGV->getName() == SGV->getName() &&
460 DGV->hasInternalLinkage());
462 NewDGV->setName(SGV->getName()); // Force the name back
463 DGV->setName(SGV->getName()); // This will cause a renaming
464 assert(NewDGV->getName() == SGV->getName() &&
465 DGV->getName() != SGV->getName());
468 // Make sure to remember this mapping...
469 ValueMap.insert(std::make_pair(SGV, NewDGV));
470 if (SGV->hasAppendingLinkage())
471 // Keep track that this is an appending variable...
472 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV));
474 } else if (SGV->isExternal()) {
475 // If SGV is external or if both SGV & DGV are external.. Just link the
476 // external globals, we aren't adding anything.
477 ValueMap.insert(std::make_pair(SGV, DGV));
479 } else if (DGV->isExternal()) { // If DGV is external but SGV is not...
480 ValueMap.insert(std::make_pair(SGV, DGV));
481 DGV->setLinkage(SGV->getLinkage()); // Inherit linkage!
482 } else if (SGV->hasWeakLinkage() || SGV->hasLinkOnceLinkage()) {
483 // At this point we know that DGV has LinkOnce, Appending, Weak, or
484 // External linkage. If DGV is Appending, this is an error.
485 if (DGV->hasAppendingLinkage())
486 return Error(Err, "Linking globals named '" + SGV->getName() +
487 " ' with 'weak' and 'appending' linkage is not allowed!");
489 if (SGV->isConstant() != DGV->isConstant())
490 return Error(Err, "Global Variable Collision on '" +
491 SGV->getType()->getDescription() + " %" + SGV->getName() +
492 "' - Global variables differ in const'ness");
494 // Otherwise, just perform the link.
495 ValueMap.insert(std::make_pair(SGV, DGV));
497 // Linkonce+Weak = Weak
498 if (DGV->hasLinkOnceLinkage() && SGV->hasWeakLinkage())
499 DGV->setLinkage(SGV->getLinkage());
501 } else if (DGV->hasWeakLinkage() || DGV->hasLinkOnceLinkage()) {
502 // At this point we know that SGV has LinkOnce, Appending, or External
503 // linkage. If SGV is Appending, this is an error.
504 if (SGV->hasAppendingLinkage())
505 return Error(Err, "Linking globals named '" + SGV->getName() +
506 " ' with 'weak' and 'appending' linkage is not allowed!");
508 if (SGV->isConstant() != DGV->isConstant())
509 return Error(Err, "Global Variable Collision on '" +
510 SGV->getType()->getDescription() + " %" + SGV->getName() +
511 "' - Global variables differ in const'ness");
513 if (!SGV->hasLinkOnceLinkage())
514 DGV->setLinkage(SGV->getLinkage()); // Inherit linkage!
515 ValueMap.insert(std::make_pair(SGV, DGV));
517 } else if (SGV->getLinkage() != DGV->getLinkage()) {
518 return Error(Err, "Global variables named '" + SGV->getName() +
519 "' have different linkage specifiers!");
520 } else if (SGV->hasExternalLinkage()) {
521 // Allow linking two exactly identical external global variables...
522 if (SGV->isConstant() != DGV->isConstant())
523 return Error(Err, "Global Variable Collision on '" +
524 SGV->getType()->getDescription() + " %" + SGV->getName() +
525 "' - Global variables differ in const'ness");
527 if (SGV->getInitializer() != DGV->getInitializer())
528 return Error(Err, "Global Variable Collision on '" +
529 SGV->getType()->getDescription() + " %" + SGV->getName() +
530 "' - External linkage globals have different initializers");
532 ValueMap.insert(std::make_pair(SGV, DGV));
533 } else if (SGV->hasAppendingLinkage()) {
534 // No linking is performed yet. Just insert a new copy of the global, and
535 // keep track of the fact that it is an appending variable in the
536 // AppendingVars map. The name is cleared out so that no linkage is
538 GlobalVariable *NewDGV =
539 new GlobalVariable(SGV->getType()->getElementType(),
540 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
543 // Make sure to remember this mapping...
544 ValueMap.insert(std::make_pair(SGV, NewDGV));
546 // Keep track that this is an appending variable...
547 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV));
549 assert(0 && "Unknown linkage!");
556 // LinkGlobalInits - Update the initializers in the Dest module now that all
557 // globals that may be referenced are in Dest.
559 static bool LinkGlobalInits(Module *Dest, const Module *Src,
560 std::map<const Value*, Value*> &ValueMap,
563 // Loop over all of the globals in the src module, mapping them over as we go
565 for (Module::const_giterator I = Src->gbegin(), E = Src->gend(); I != E; ++I){
566 const GlobalVariable *SGV = I;
568 if (SGV->hasInitializer()) { // Only process initialized GV's
569 // Figure out what the initializer looks like in the dest module...
571 cast<Constant>(RemapOperand(SGV->getInitializer(), ValueMap, 0));
573 GlobalVariable *DGV = cast<GlobalVariable>(ValueMap[SGV]);
574 if (DGV->hasInitializer()) {
575 assert(SGV->getLinkage() == DGV->getLinkage());
576 if (SGV->hasExternalLinkage()) {
577 if (DGV->getInitializer() != SInit)
578 return Error(Err, "Global Variable Collision on '" +
579 SGV->getType()->getDescription() +"':%"+SGV->getName()+
580 " - Global variables have different initializers");
581 } else if (DGV->hasLinkOnceLinkage() || DGV->hasWeakLinkage()) {
582 // Nothing is required, mapped values will take the new global
584 } else if (DGV->hasAppendingLinkage()) {
585 assert(0 && "Appending linkage unimplemented!");
587 assert(0 && "Unknown linkage!");
590 // Copy the initializer over now...
591 DGV->setInitializer(SInit);
598 // LinkFunctionProtos - Link the functions together between the two modules,
599 // without doing function bodies... this just adds external function prototypes
600 // to the Dest function...
602 static bool LinkFunctionProtos(Module *Dest, const Module *Src,
603 std::map<const Value*, Value*> &ValueMap,
605 SymbolTable *ST = (SymbolTable*)&Dest->getSymbolTable();
607 // Loop over all of the functions in the src module, mapping them over as we
610 for (Module::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) {
611 const Function *SF = I; // SrcFunction
614 // The same named thing is a Function, because the only two things
615 // that may be in a module level symbol table are Global Vars and
616 // Functions, and they both have distinct, nonoverlapping, possible types.
618 DF = cast_or_null<Function>(FindGlobalNamed(SF->getName(), SF->getType(),
621 if (!DF || SF->hasInternalLinkage() || DF->hasInternalLinkage()) {
622 // Function does not already exist, simply insert an function signature
623 // identical to SF into the dest module...
624 Function *NewDF = new Function(SF->getFunctionType(), SF->getLinkage(),
625 SF->getName(), Dest);
627 // If the LLVM runtime renamed the function, but it is an externally
628 // visible symbol, DF must be an existing function with internal linkage.
630 if (NewDF->getName() != SF->getName() && !NewDF->hasInternalLinkage()) {
631 assert(DF && DF->getName() == SF->getName() &&DF->hasInternalLinkage());
633 NewDF->setName(SF->getName()); // Force the name back
634 DF->setName(SF->getName()); // This will cause a renaming
635 assert(NewDF->getName() == SF->getName() &&
636 DF->getName() != SF->getName());
639 // ... and remember this mapping...
640 ValueMap.insert(std::make_pair(SF, NewDF));
641 } else if (SF->isExternal()) {
642 // If SF is external or if both SF & DF are external.. Just link the
643 // external functions, we aren't adding anything.
644 ValueMap.insert(std::make_pair(SF, DF));
645 } else if (DF->isExternal()) { // If DF is external but SF is not...
646 // Link the external functions, update linkage qualifiers
647 ValueMap.insert(std::make_pair(SF, DF));
648 DF->setLinkage(SF->getLinkage());
650 } else if (SF->hasWeakLinkage() || SF->hasLinkOnceLinkage()) {
651 // At this point we know that DF has LinkOnce, Weak, or External linkage.
652 ValueMap.insert(std::make_pair(SF, DF));
654 // Linkonce+Weak = Weak
655 if (DF->hasLinkOnceLinkage() && SF->hasWeakLinkage())
656 DF->setLinkage(SF->getLinkage());
658 } else if (DF->hasWeakLinkage() || DF->hasLinkOnceLinkage()) {
659 // At this point we know that SF has LinkOnce or External linkage.
660 ValueMap.insert(std::make_pair(SF, DF));
661 if (!SF->hasLinkOnceLinkage()) // Don't inherit linkonce linkage
662 DF->setLinkage(SF->getLinkage());
664 } else if (SF->getLinkage() != DF->getLinkage()) {
665 return Error(Err, "Functions named '" + SF->getName() +
666 "' have different linkage specifiers!");
667 } else if (SF->hasExternalLinkage()) {
668 // The function is defined in both modules!!
669 return Error(Err, "Function '" +
670 SF->getFunctionType()->getDescription() + "':\"" +
671 SF->getName() + "\" - Function is already defined!");
673 assert(0 && "Unknown linkage configuration found!");
679 // LinkFunctionBody - Copy the source function over into the dest function and
680 // fix up references to values. At this point we know that Dest is an external
681 // function, and that Src is not.
683 static bool LinkFunctionBody(Function *Dest, const Function *Src,
684 std::map<const Value*, Value*> &GlobalMap,
686 assert(Src && Dest && Dest->isExternal() && !Src->isExternal());
687 std::map<const Value*, Value*> LocalMap; // Map for function local values
689 // Go through and convert function arguments over...
690 Function::aiterator DI = Dest->abegin();
691 for (Function::const_aiterator I = Src->abegin(), E = Src->aend();
693 DI->setName(I->getName()); // Copy the name information over...
695 // Add a mapping to our local map
696 LocalMap.insert(std::make_pair(I, DI));
699 // Loop over all of the basic blocks, copying the instructions over...
701 for (Function::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) {
702 // Create new basic block and add to mapping and the Dest function...
703 BasicBlock *DBB = new BasicBlock(I->getName(), Dest);
704 LocalMap.insert(std::make_pair(I, DBB));
706 // Loop over all of the instructions in the src basic block, copying them
707 // over. Note that this is broken in a strict sense because the cloned
708 // instructions will still be referencing values in the Src module, not
709 // the remapped values. In our case, however, we will not get caught and
710 // so we can delay patching the values up until later...
712 for (BasicBlock::const_iterator II = I->begin(), IE = I->end();
714 Instruction *DI = II->clone();
715 DI->setName(II->getName());
716 DBB->getInstList().push_back(DI);
717 LocalMap.insert(std::make_pair(II, DI));
721 // At this point, all of the instructions and values of the function are now
722 // copied over. The only problem is that they are still referencing values in
723 // the Source function as operands. Loop through all of the operands of the
724 // functions and patch them up to point to the local versions...
726 for (Function::iterator BB = Dest->begin(), BE = Dest->end(); BB != BE; ++BB)
727 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
728 for (Instruction::op_iterator OI = I->op_begin(), OE = I->op_end();
730 *OI = RemapOperand(*OI, LocalMap, &GlobalMap);
736 // LinkFunctionBodies - Link in the function bodies that are defined in the
737 // source module into the DestModule. This consists basically of copying the
738 // function over and fixing up references to values.
740 static bool LinkFunctionBodies(Module *Dest, const Module *Src,
741 std::map<const Value*, Value*> &ValueMap,
744 // Loop over all of the functions in the src module, mapping them over as we
747 for (Module::const_iterator SF = Src->begin(), E = Src->end(); SF != E; ++SF){
748 if (!SF->isExternal()) { // No body if function is external
749 Function *DF = cast<Function>(ValueMap[SF]); // Destination function
751 // DF not external SF external?
752 if (DF->isExternal()) {
753 // Only provide the function body if there isn't one already.
754 if (LinkFunctionBody(DF, SF, ValueMap, Err))
762 // LinkAppendingVars - If there were any appending global variables, link them
763 // together now. Return true on error.
765 static bool LinkAppendingVars(Module *M,
766 std::multimap<std::string, GlobalVariable *> &AppendingVars,
767 std::string *ErrorMsg) {
768 if (AppendingVars.empty()) return false; // Nothing to do.
770 // Loop over the multimap of appending vars, processing any variables with the
771 // same name, forming a new appending global variable with both of the
772 // initializers merged together, then rewrite references to the old variables
775 std::vector<Constant*> Inits;
776 while (AppendingVars.size() > 1) {
777 // Get the first two elements in the map...
778 std::multimap<std::string,
779 GlobalVariable*>::iterator Second = AppendingVars.begin(), First=Second++;
781 // If the first two elements are for different names, there is no pair...
782 // Otherwise there is a pair, so link them together...
783 if (First->first == Second->first) {
784 GlobalVariable *G1 = First->second, *G2 = Second->second;
785 const ArrayType *T1 = cast<ArrayType>(G1->getType()->getElementType());
786 const ArrayType *T2 = cast<ArrayType>(G2->getType()->getElementType());
788 // Check to see that they two arrays agree on type...
789 if (T1->getElementType() != T2->getElementType())
790 return Error(ErrorMsg,
791 "Appending variables with different element types need to be linked!");
792 if (G1->isConstant() != G2->isConstant())
793 return Error(ErrorMsg,
794 "Appending variables linked with different const'ness!");
796 unsigned NewSize = T1->getNumElements() + T2->getNumElements();
797 ArrayType *NewType = ArrayType::get(T1->getElementType(), NewSize);
799 // Create the new global variable...
801 new GlobalVariable(NewType, G1->isConstant(), G1->getLinkage(),
802 /*init*/0, First->first, M);
804 // Merge the initializer...
805 Inits.reserve(NewSize);
806 ConstantArray *I = cast<ConstantArray>(G1->getInitializer());
807 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i)
808 Inits.push_back(cast<Constant>(I->getValues()[i]));
809 I = cast<ConstantArray>(G2->getInitializer());
810 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i)
811 Inits.push_back(cast<Constant>(I->getValues()[i]));
812 NG->setInitializer(ConstantArray::get(NewType, Inits));
815 // Replace any uses of the two global variables with uses of the new
818 // FIXME: This should rewrite simple/straight-forward uses such as
819 // getelementptr instructions to not use the Cast!
820 ConstantPointerRef *NGCP = ConstantPointerRef::get(NG);
821 G1->replaceAllUsesWith(ConstantExpr::getCast(NGCP, G1->getType()));
822 G2->replaceAllUsesWith(ConstantExpr::getCast(NGCP, G2->getType()));
824 // Remove the two globals from the module now...
825 M->getGlobalList().erase(G1);
826 M->getGlobalList().erase(G2);
828 // Put the new global into the AppendingVars map so that we can handle
829 // linking of more than two vars...
832 AppendingVars.erase(First);
839 // LinkModules - This function links two modules together, with the resulting
840 // left module modified to be the composite of the two input modules. If an
841 // error occurs, true is returned and ErrorMsg (if not null) is set to indicate
842 // the problem. Upon failure, the Dest module could be in a modified state, and
843 // shouldn't be relied on to be consistent.
845 bool LinkModules(Module *Dest, const Module *Src, std::string *ErrorMsg) {
846 if (Dest->getEndianness() == Module::AnyEndianness)
847 Dest->setEndianness(Src->getEndianness());
848 if (Dest->getPointerSize() == Module::AnyPointerSize)
849 Dest->setPointerSize(Src->getPointerSize());
851 if (Src->getEndianness() != Module::AnyEndianness &&
852 Dest->getEndianness() != Src->getEndianness())
853 std::cerr << "WARNING: Linking two modules of different endianness!\n";
854 if (Src->getPointerSize() != Module::AnyPointerSize &&
855 Dest->getPointerSize() != Src->getPointerSize())
856 std::cerr << "WARNING: Linking two modules of different pointer size!\n";
858 // LinkTypes - Go through the symbol table of the Src module and see if any
859 // types are named in the src module that are not named in the Dst module.
860 // Make sure there are no type name conflicts.
862 if (LinkTypes(Dest, Src, ErrorMsg)) return true;
864 // ValueMap - Mapping of values from what they used to be in Src, to what they
867 std::map<const Value*, Value*> ValueMap;
869 // AppendingVars - Keep track of global variables in the destination module
870 // with appending linkage. After the module is linked together, they are
871 // appended and the module is rewritten.
873 std::multimap<std::string, GlobalVariable *> AppendingVars;
875 // Add all of the appending globals already in the Dest module to
877 for (Module::giterator I = Dest->gbegin(), E = Dest->gend(); I != E; ++I)
878 if (I->hasAppendingLinkage())
879 AppendingVars.insert(std::make_pair(I->getName(), I));
881 // Insert all of the globals in src into the Dest module... without linking
882 // initializers (which could refer to functions not yet mapped over).
884 if (LinkGlobals(Dest, Src, ValueMap, AppendingVars, ErrorMsg)) return true;
886 // Link the functions together between the two modules, without doing function
887 // bodies... this just adds external function prototypes to the Dest
888 // function... We do this so that when we begin processing function bodies,
889 // all of the global values that may be referenced are available in our
892 if (LinkFunctionProtos(Dest, Src, ValueMap, ErrorMsg)) return true;
894 // Update the initializers in the Dest module now that all globals that may
895 // be referenced are in Dest.
897 if (LinkGlobalInits(Dest, Src, ValueMap, ErrorMsg)) return true;
899 // Link in the function bodies that are defined in the source module into the
900 // DestModule. This consists basically of copying the function over and
901 // fixing up references to values.
903 if (LinkFunctionBodies(Dest, Src, ValueMap, ErrorMsg)) return true;
905 // If there were any appending global variables, link them together now.
907 if (LinkAppendingVars(Dest, AppendingVars, ErrorMsg)) return true;
912 } // End llvm namespace