1 //===- Linker.cpp - Module Linker Implementation --------------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by the LLVM research group and is distributed under
6 // the University of Illinois Open Source License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements the LLVM module linker.
12 // Specifically, this:
13 // * Merges global variables between the two modules
14 // * Uninit + Uninit = Init, Init + Uninit = Init, Init + Init = Error if !=
15 // * Merges functions between two modules
17 //===----------------------------------------------------------------------===//
19 #include "llvm/Support/Linker.h"
20 #include "llvm/Constants.h"
21 #include "llvm/DerivedTypes.h"
22 #include "llvm/Module.h"
23 #include "llvm/SymbolTable.h"
24 #include "llvm/Instructions.h"
25 #include "llvm/Assembly/Writer.h"
30 // Error - Simple wrapper function to conditionally assign to E and return true.
31 // This just makes error return conditions a little bit simpler...
33 static inline bool Error(std::string *E, const std::string &Message) {
39 // Function: ResolveTypes()
42 // Attempt to link the two specified types together.
45 // DestTy - The type to which we wish to resolve.
46 // SrcTy - The original type which we want to resolve.
47 // Name - The name of the type.
50 // DestST - The symbol table in which the new type should be placed.
53 // true - There is an error and the types cannot yet be linked.
56 static bool ResolveTypes(const Type *DestTy, const Type *SrcTy,
57 SymbolTable *DestST, const std::string &Name) {
58 if (DestTy == SrcTy) return false; // If already equal, noop
60 // Does the type already exist in the module?
61 if (DestTy && !isa<OpaqueType>(DestTy)) { // Yup, the type already exists...
62 if (const OpaqueType *OT = dyn_cast<OpaqueType>(SrcTy)) {
63 const_cast<OpaqueType*>(OT)->refineAbstractTypeTo(DestTy);
65 return true; // Cannot link types... neither is opaque and not-equal
67 } else { // Type not in dest module. Add it now.
68 if (DestTy) // Type _is_ in module, just opaque...
69 const_cast<OpaqueType*>(cast<OpaqueType>(DestTy))
70 ->refineAbstractTypeTo(SrcTy);
71 else if (!Name.empty())
72 DestST->insert(Name, const_cast<Type*>(SrcTy));
77 static const FunctionType *getFT(const PATypeHolder &TH) {
78 return cast<FunctionType>(TH.get());
80 static const StructType *getST(const PATypeHolder &TH) {
81 return cast<StructType>(TH.get());
84 // RecursiveResolveTypes - This is just like ResolveTypes, except that it
85 // recurses down into derived types, merging the used types if the parent types
88 static bool RecursiveResolveTypesI(const PATypeHolder &DestTy,
89 const PATypeHolder &SrcTy,
90 SymbolTable *DestST, const std::string &Name,
91 std::vector<std::pair<PATypeHolder, PATypeHolder> > &Pointers) {
92 const Type *SrcTyT = SrcTy.get();
93 const Type *DestTyT = DestTy.get();
94 if (DestTyT == SrcTyT) return false; // If already equal, noop
96 // If we found our opaque type, resolve it now!
97 if (isa<OpaqueType>(DestTyT) || isa<OpaqueType>(SrcTyT))
98 return ResolveTypes(DestTyT, SrcTyT, DestST, Name);
100 // Two types cannot be resolved together if they are of different primitive
101 // type. For example, we cannot resolve an int to a float.
102 if (DestTyT->getTypeID() != SrcTyT->getTypeID()) return true;
104 // Otherwise, resolve the used type used by this derived type...
105 switch (DestTyT->getTypeID()) {
106 case Type::FunctionTyID: {
107 if (cast<FunctionType>(DestTyT)->isVarArg() !=
108 cast<FunctionType>(SrcTyT)->isVarArg() ||
109 cast<FunctionType>(DestTyT)->getNumContainedTypes() !=
110 cast<FunctionType>(SrcTyT)->getNumContainedTypes())
112 for (unsigned i = 0, e = getFT(DestTy)->getNumContainedTypes(); i != e; ++i)
113 if (RecursiveResolveTypesI(getFT(DestTy)->getContainedType(i),
114 getFT(SrcTy)->getContainedType(i), DestST, "",
119 case Type::StructTyID: {
120 if (getST(DestTy)->getNumContainedTypes() !=
121 getST(SrcTy)->getNumContainedTypes()) return 1;
122 for (unsigned i = 0, e = getST(DestTy)->getNumContainedTypes(); i != e; ++i)
123 if (RecursiveResolveTypesI(getST(DestTy)->getContainedType(i),
124 getST(SrcTy)->getContainedType(i), DestST, "",
129 case Type::ArrayTyID: {
130 const ArrayType *DAT = cast<ArrayType>(DestTy.get());
131 const ArrayType *SAT = cast<ArrayType>(SrcTy.get());
132 if (DAT->getNumElements() != SAT->getNumElements()) return true;
133 return RecursiveResolveTypesI(DAT->getElementType(), SAT->getElementType(),
134 DestST, "", Pointers);
136 case Type::PointerTyID: {
137 // If this is a pointer type, check to see if we have already seen it. If
138 // so, we are in a recursive branch. Cut off the search now. We cannot use
139 // an associative container for this search, because the type pointers (keys
140 // in the container) change whenever types get resolved...
142 for (unsigned i = 0, e = Pointers.size(); i != e; ++i)
143 if (Pointers[i].first == DestTy)
144 return Pointers[i].second != SrcTy;
146 // Otherwise, add the current pointers to the vector to stop recursion on
148 Pointers.push_back(std::make_pair(DestTyT, SrcTyT));
150 RecursiveResolveTypesI(cast<PointerType>(DestTy.get())->getElementType(),
151 cast<PointerType>(SrcTy.get())->getElementType(),
152 DestST, "", Pointers);
156 default: assert(0 && "Unexpected type!"); return true;
160 static bool RecursiveResolveTypes(const PATypeHolder &DestTy,
161 const PATypeHolder &SrcTy,
162 SymbolTable *DestST, const std::string &Name){
163 std::vector<std::pair<PATypeHolder, PATypeHolder> > PointerTypes;
164 return RecursiveResolveTypesI(DestTy, SrcTy, DestST, Name, PointerTypes);
168 // LinkTypes - Go through the symbol table of the Src module and see if any
169 // types are named in the src module that are not named in the Dst module.
170 // Make sure there are no type name conflicts.
172 static bool LinkTypes(Module *Dest, const Module *Src, std::string *Err) {
173 SymbolTable *DestST = &Dest->getSymbolTable();
174 const SymbolTable *SrcST = &Src->getSymbolTable();
176 // Look for a type plane for Type's...
177 SymbolTable::type_const_iterator TI = SrcST->type_begin();
178 SymbolTable::type_const_iterator TE = SrcST->type_end();
179 if (TI == TE) return false; // No named types, do nothing.
181 // Some types cannot be resolved immediately because they depend on other
182 // types being resolved to each other first. This contains a list of types we
183 // are waiting to recheck.
184 std::vector<std::string> DelayedTypesToResolve;
186 for ( ; TI != TE; ++TI ) {
187 const std::string &Name = TI->first;
188 const Type *RHS = TI->second;
190 // Check to see if this type name is already in the dest module...
191 Type *Entry = DestST->lookupType(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 = SrcST->lookupType(Name);
208 Type *T2 = DestST->lookupType(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(SrcST->lookupType(Name));
223 PATypeHolder T2(DestST->lookupType(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 = SrcST->lookupType(Name);
241 const Type *T2 = DestST->lookupType(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 isa<ConstantAggregateZero>(CPV))
290 return const_cast<Constant*>(CPV); // Simple constants stay identical...
292 Constant *Result = 0;
294 if (const ConstantArray *CPA = dyn_cast<ConstantArray>(CPV)) {
295 const std::vector<Use> &Ops = CPA->getValues();
296 std::vector<Constant*> Operands(Ops.size());
297 for (unsigned i = 0, e = Ops.size(); i != e; ++i)
299 cast<Constant>(RemapOperand(Ops[i], LocalMap, GlobalMap));
300 Result = ConstantArray::get(cast<ArrayType>(CPA->getType()), Operands);
301 } else if (const ConstantStruct *CPS = dyn_cast<ConstantStruct>(CPV)) {
302 const std::vector<Use> &Ops = CPS->getValues();
303 std::vector<Constant*> Operands(Ops.size());
304 for (unsigned i = 0; i < Ops.size(); ++i)
306 cast<Constant>(RemapOperand(Ops[i], LocalMap, GlobalMap));
307 Result = ConstantStruct::get(cast<StructType>(CPS->getType()), Operands);
308 } else if (isa<ConstantPointerNull>(CPV)) {
309 Result = const_cast<Constant*>(CPV);
310 } else if (isa<GlobalValue>(CPV)) {
311 Result = cast<Constant>(RemapOperand(CPV, LocalMap, GlobalMap));
312 } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CPV)) {
313 if (CE->getOpcode() == Instruction::GetElementPtr) {
314 Value *Ptr = RemapOperand(CE->getOperand(0), LocalMap, GlobalMap);
315 std::vector<Constant*> Indices;
316 Indices.reserve(CE->getNumOperands()-1);
317 for (unsigned i = 1, e = CE->getNumOperands(); i != e; ++i)
318 Indices.push_back(cast<Constant>(RemapOperand(CE->getOperand(i),
319 LocalMap, GlobalMap)));
321 Result = ConstantExpr::getGetElementPtr(cast<Constant>(Ptr), Indices);
322 } else if (CE->getNumOperands() == 1) {
324 assert(CE->getOpcode() == Instruction::Cast);
325 Value *V = RemapOperand(CE->getOperand(0), LocalMap, GlobalMap);
326 Result = ConstantExpr::getCast(cast<Constant>(V), CE->getType());
327 } else if (CE->getNumOperands() == 3) {
328 // Select instruction
329 assert(CE->getOpcode() == Instruction::Select);
330 Value *V1 = RemapOperand(CE->getOperand(0), LocalMap, GlobalMap);
331 Value *V2 = RemapOperand(CE->getOperand(1), LocalMap, GlobalMap);
332 Value *V3 = RemapOperand(CE->getOperand(2), LocalMap, GlobalMap);
333 Result = ConstantExpr::getSelect(cast<Constant>(V1), cast<Constant>(V2),
335 } else if (CE->getNumOperands() == 2) {
336 // Binary operator...
337 Value *V1 = RemapOperand(CE->getOperand(0), LocalMap, GlobalMap);
338 Value *V2 = RemapOperand(CE->getOperand(1), LocalMap, GlobalMap);
340 Result = ConstantExpr::get(CE->getOpcode(), cast<Constant>(V1),
343 assert(0 && "Unknown constant expr type!");
347 assert(0 && "Unknown type of derived type constant value!");
350 // Cache the mapping in our local map structure...
352 GlobalMap->insert(std::make_pair(In, Result));
354 LocalMap.insert(std::make_pair(In, Result));
358 std::cerr << "XXX LocalMap: \n";
362 std::cerr << "XXX GlobalMap: \n";
363 PrintMap(*GlobalMap);
366 std::cerr << "Couldn't remap value: " << (void*)In << " " << *In << "\n";
367 assert(0 && "Couldn't remap value!");
371 /// FindGlobalNamed - Look in the specified symbol table for a global with the
372 /// specified name and type. If an exactly matching global does not exist, see
373 /// if there is a global which is "type compatible" with the specified
374 /// name/type. This allows us to resolve things like '%x = global int*' with
375 /// '%x = global opaque*'.
377 static GlobalValue *FindGlobalNamed(const std::string &Name, const Type *Ty,
379 // See if an exact match exists in the symbol table...
380 if (Value *V = ST->lookup(Ty, Name)) return cast<GlobalValue>(V);
382 // It doesn't exist exactly, scan through all of the type planes in the symbol
383 // table, checking each of them for a type-compatible version.
385 for (SymbolTable::plane_iterator PI = ST->plane_begin(), PE = ST->plane_end();
387 // Does this type plane contain an entry with the specified name?
388 SymbolTable::ValueMap &VM = PI->second;
389 SymbolTable::value_iterator VI = VM.find(Name);
391 if (VI != VM.end()) {
392 // Ensure that this type if placed correctly into the symbol table.
393 GlobalValue *ValPtr = cast<GlobalValue>(VI->second);
394 assert(ValPtr->getType() == PI->first && "Type conflict!");
396 // Determine whether we can fold the two types together, resolving them.
397 // If so, we can use this value.
398 if (!ValPtr->hasInternalLinkage() &&
399 !RecursiveResolveTypes(Ty, PI->first, ST, ""))
403 return 0; // Otherwise, nothing could be found.
407 // LinkGlobals - Loop through the global variables in the src module and merge
408 // them into the dest module.
410 static bool LinkGlobals(Module *Dest, const Module *Src,
411 std::map<const Value*, Value*> &ValueMap,
412 std::multimap<std::string, GlobalVariable *> &AppendingVars,
414 // We will need a module level symbol table if the src module has a module
415 // level symbol table...
416 SymbolTable *ST = (SymbolTable*)&Dest->getSymbolTable();
418 // Loop over all of the globals in the src module, mapping them over as we go
420 for (Module::const_giterator I = Src->gbegin(), E = Src->gend(); I != E; ++I){
421 const GlobalVariable *SGV = I;
422 GlobalVariable *DGV = 0;
423 if (SGV->hasName() && !SGV->hasInternalLinkage()) {
424 // A same named thing is a global variable, because the only two things
425 // that may be in a module level symbol table are Global Vars and
426 // Functions, and they both have distinct, nonoverlapping, possible types.
428 DGV = cast_or_null<GlobalVariable>(FindGlobalNamed(SGV->getName(),
429 SGV->getType(), ST));
432 assert(SGV->hasInitializer() || SGV->hasExternalLinkage() &&
433 "Global must either be external or have an initializer!");
435 bool SGExtern = SGV->isExternal();
436 bool DGExtern = DGV ? DGV->isExternal() : false;
438 if (!DGV || DGV->hasInternalLinkage() || SGV->hasInternalLinkage()) {
439 // No linking to be performed, simply create an identical version of the
440 // symbol over in the dest module... the initializer will be filled in
441 // later by LinkGlobalInits...
443 GlobalVariable *NewDGV =
444 new GlobalVariable(SGV->getType()->getElementType(),
445 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
446 SGV->getName(), Dest);
448 // If the LLVM runtime renamed the global, but it is an externally visible
449 // symbol, DGV must be an existing global with internal linkage. Rename
451 if (NewDGV->getName() != SGV->getName() && !NewDGV->hasInternalLinkage()){
452 assert(DGV && DGV->getName() == SGV->getName() &&
453 DGV->hasInternalLinkage());
455 NewDGV->setName(SGV->getName()); // Force the name back
456 DGV->setName(SGV->getName()); // This will cause a renaming
457 assert(NewDGV->getName() == SGV->getName() &&
458 DGV->getName() != SGV->getName());
461 // Make sure to remember this mapping...
462 ValueMap.insert(std::make_pair(SGV, NewDGV));
463 if (SGV->hasAppendingLinkage())
464 // Keep track that this is an appending variable...
465 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV));
467 } else if (SGV->isExternal()) {
468 // If SGV is external or if both SGV & DGV are external.. Just link the
469 // external globals, we aren't adding anything.
470 ValueMap.insert(std::make_pair(SGV, DGV));
472 } else if (DGV->isExternal()) { // If DGV is external but SGV is not...
473 ValueMap.insert(std::make_pair(SGV, DGV));
474 DGV->setLinkage(SGV->getLinkage()); // Inherit linkage!
475 } else if (SGV->hasWeakLinkage() || SGV->hasLinkOnceLinkage()) {
476 // At this point we know that DGV has LinkOnce, Appending, Weak, or
477 // External linkage. If DGV is Appending, this is an error.
478 if (DGV->hasAppendingLinkage())
479 return Error(Err, "Linking globals named '" + SGV->getName() +
480 " ' with 'weak' and 'appending' linkage is not allowed!");
482 if (SGV->isConstant() != DGV->isConstant())
483 return Error(Err, "Global Variable Collision on '" +
484 SGV->getType()->getDescription() + " %" + SGV->getName() +
485 "' - Global variables differ in const'ness");
487 // Otherwise, just perform the link.
488 ValueMap.insert(std::make_pair(SGV, DGV));
490 // Linkonce+Weak = Weak
491 if (DGV->hasLinkOnceLinkage() && SGV->hasWeakLinkage())
492 DGV->setLinkage(SGV->getLinkage());
494 } else if (DGV->hasWeakLinkage() || DGV->hasLinkOnceLinkage()) {
495 // At this point we know that SGV has LinkOnce, Appending, or External
496 // linkage. If SGV is Appending, this is an error.
497 if (SGV->hasAppendingLinkage())
498 return Error(Err, "Linking globals named '" + SGV->getName() +
499 " ' with 'weak' and 'appending' linkage is not allowed!");
501 if (SGV->isConstant() != DGV->isConstant())
502 return Error(Err, "Global Variable Collision on '" +
503 SGV->getType()->getDescription() + " %" + SGV->getName() +
504 "' - Global variables differ in const'ness");
506 if (!SGV->hasLinkOnceLinkage())
507 DGV->setLinkage(SGV->getLinkage()); // Inherit linkage!
508 ValueMap.insert(std::make_pair(SGV, DGV));
510 } else if (SGV->getLinkage() != DGV->getLinkage()) {
511 return Error(Err, "Global variables named '" + SGV->getName() +
512 "' have different linkage specifiers!");
513 } else if (SGV->hasExternalLinkage()) {
514 // Allow linking two exactly identical external global variables...
515 if (SGV->isConstant() != DGV->isConstant())
516 return Error(Err, "Global Variable Collision on '" +
517 SGV->getType()->getDescription() + " %" + SGV->getName() +
518 "' - Global variables differ in const'ness");
520 if (SGV->getInitializer() != DGV->getInitializer())
521 return Error(Err, "Global Variable Collision on '" +
522 SGV->getType()->getDescription() + " %" + SGV->getName() +
523 "' - External linkage globals have different initializers");
525 ValueMap.insert(std::make_pair(SGV, DGV));
526 } else if (SGV->hasAppendingLinkage()) {
527 // No linking is performed yet. Just insert a new copy of the global, and
528 // keep track of the fact that it is an appending variable in the
529 // AppendingVars map. The name is cleared out so that no linkage is
531 GlobalVariable *NewDGV =
532 new GlobalVariable(SGV->getType()->getElementType(),
533 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
536 // Make sure to remember this mapping...
537 ValueMap.insert(std::make_pair(SGV, NewDGV));
539 // Keep track that this is an appending variable...
540 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV));
542 assert(0 && "Unknown linkage!");
549 // LinkGlobalInits - Update the initializers in the Dest module now that all
550 // globals that may be referenced are in Dest.
552 static bool LinkGlobalInits(Module *Dest, const Module *Src,
553 std::map<const Value*, Value*> &ValueMap,
556 // Loop over all of the globals in the src module, mapping them over as we go
558 for (Module::const_giterator I = Src->gbegin(), E = Src->gend(); I != E; ++I){
559 const GlobalVariable *SGV = I;
561 if (SGV->hasInitializer()) { // Only process initialized GV's
562 // Figure out what the initializer looks like in the dest module...
564 cast<Constant>(RemapOperand(SGV->getInitializer(), ValueMap, 0));
566 GlobalVariable *DGV = cast<GlobalVariable>(ValueMap[SGV]);
567 if (DGV->hasInitializer()) {
568 if (SGV->hasExternalLinkage()) {
569 if (DGV->getInitializer() != SInit)
570 return Error(Err, "Global Variable Collision on '" +
571 SGV->getType()->getDescription() +"':%"+SGV->getName()+
572 " - Global variables have different initializers");
573 } else if (DGV->hasLinkOnceLinkage() || DGV->hasWeakLinkage()) {
574 // Nothing is required, mapped values will take the new global
576 } else if (SGV->hasLinkOnceLinkage() || SGV->hasWeakLinkage()) {
577 // Nothing is required, mapped values will take the new global
579 } else if (DGV->hasAppendingLinkage()) {
580 assert(0 && "Appending linkage unimplemented!");
582 assert(0 && "Unknown linkage!");
585 // Copy the initializer over now...
586 DGV->setInitializer(SInit);
593 // LinkFunctionProtos - Link the functions together between the two modules,
594 // without doing function bodies... this just adds external function prototypes
595 // to the Dest function...
597 static bool LinkFunctionProtos(Module *Dest, const Module *Src,
598 std::map<const Value*, Value*> &ValueMap,
600 SymbolTable *ST = (SymbolTable*)&Dest->getSymbolTable();
602 // Loop over all of the functions in the src module, mapping them over as we
605 for (Module::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) {
606 const Function *SF = I; // SrcFunction
608 if (SF->hasName() && !SF->hasInternalLinkage())
609 // The same named thing is a Function, because the only two things
610 // that may be in a module level symbol table are Global Vars and
611 // Functions, and they both have distinct, nonoverlapping, possible types.
613 DF = cast_or_null<Function>(FindGlobalNamed(SF->getName(), SF->getType(),
616 if (!DF || SF->hasInternalLinkage() || DF->hasInternalLinkage()) {
617 // Function does not already exist, simply insert an function signature
618 // identical to SF into the dest module...
619 Function *NewDF = new Function(SF->getFunctionType(), SF->getLinkage(),
620 SF->getName(), Dest);
622 // If the LLVM runtime renamed the function, but it is an externally
623 // visible symbol, DF must be an existing function with internal linkage.
625 if (NewDF->getName() != SF->getName() && !NewDF->hasInternalLinkage()) {
626 assert(DF && DF->getName() == SF->getName() &&DF->hasInternalLinkage());
628 NewDF->setName(SF->getName()); // Force the name back
629 DF->setName(SF->getName()); // This will cause a renaming
630 assert(NewDF->getName() == SF->getName() &&
631 DF->getName() != SF->getName());
634 // ... and remember this mapping...
635 ValueMap.insert(std::make_pair(SF, NewDF));
636 } else if (SF->isExternal()) {
637 // If SF is external or if both SF & DF are external.. Just link the
638 // external functions, we aren't adding anything.
639 ValueMap.insert(std::make_pair(SF, DF));
640 } else if (DF->isExternal()) { // If DF is external but SF is not...
641 // Link the external functions, update linkage qualifiers
642 ValueMap.insert(std::make_pair(SF, DF));
643 DF->setLinkage(SF->getLinkage());
645 } else if (SF->hasWeakLinkage() || SF->hasLinkOnceLinkage()) {
646 // At this point we know that DF has LinkOnce, Weak, or External linkage.
647 ValueMap.insert(std::make_pair(SF, DF));
649 // Linkonce+Weak = Weak
650 if (DF->hasLinkOnceLinkage() && SF->hasWeakLinkage())
651 DF->setLinkage(SF->getLinkage());
653 } else if (DF->hasWeakLinkage() || DF->hasLinkOnceLinkage()) {
654 // At this point we know that SF has LinkOnce or External linkage.
655 ValueMap.insert(std::make_pair(SF, DF));
656 if (!SF->hasLinkOnceLinkage()) // Don't inherit linkonce linkage
657 DF->setLinkage(SF->getLinkage());
659 } else if (SF->getLinkage() != DF->getLinkage()) {
660 return Error(Err, "Functions named '" + SF->getName() +
661 "' have different linkage specifiers!");
662 } else if (SF->hasExternalLinkage()) {
663 // The function is defined in both modules!!
664 return Error(Err, "Function '" +
665 SF->getFunctionType()->getDescription() + "':\"" +
666 SF->getName() + "\" - Function is already defined!");
668 assert(0 && "Unknown linkage configuration found!");
674 // LinkFunctionBody - Copy the source function over into the dest function and
675 // fix up references to values. At this point we know that Dest is an external
676 // function, and that Src is not.
678 static bool LinkFunctionBody(Function *Dest, const Function *Src,
679 std::map<const Value*, Value*> &GlobalMap,
681 assert(Src && Dest && Dest->isExternal() && !Src->isExternal());
682 std::map<const Value*, Value*> LocalMap; // Map for function local values
684 // Go through and convert function arguments over...
685 Function::aiterator DI = Dest->abegin();
686 for (Function::const_aiterator I = Src->abegin(), E = Src->aend();
688 DI->setName(I->getName()); // Copy the name information over...
690 // Add a mapping to our local map
691 LocalMap.insert(std::make_pair(I, DI));
694 // Loop over all of the basic blocks, copying the instructions over...
696 for (Function::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) {
697 // Create new basic block and add to mapping and the Dest function...
698 BasicBlock *DBB = new BasicBlock(I->getName(), Dest);
699 LocalMap.insert(std::make_pair(I, DBB));
701 // Loop over all of the instructions in the src basic block, copying them
702 // over. Note that this is broken in a strict sense because the cloned
703 // instructions will still be referencing values in the Src module, not
704 // the remapped values. In our case, however, we will not get caught and
705 // so we can delay patching the values up until later...
707 for (BasicBlock::const_iterator II = I->begin(), IE = I->end();
709 Instruction *DI = II->clone();
710 DI->setName(II->getName());
711 DBB->getInstList().push_back(DI);
712 LocalMap.insert(std::make_pair(II, DI));
716 // At this point, all of the instructions and values of the function are now
717 // copied over. The only problem is that they are still referencing values in
718 // the Source function as operands. Loop through all of the operands of the
719 // functions and patch them up to point to the local versions...
721 for (Function::iterator BB = Dest->begin(), BE = Dest->end(); BB != BE; ++BB)
722 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
723 for (Instruction::op_iterator OI = I->op_begin(), OE = I->op_end();
725 *OI = RemapOperand(*OI, LocalMap, &GlobalMap);
731 // LinkFunctionBodies - Link in the function bodies that are defined in the
732 // source module into the DestModule. This consists basically of copying the
733 // function over and fixing up references to values.
735 static bool LinkFunctionBodies(Module *Dest, const Module *Src,
736 std::map<const Value*, Value*> &ValueMap,
739 // Loop over all of the functions in the src module, mapping them over as we
742 for (Module::const_iterator SF = Src->begin(), E = Src->end(); SF != E; ++SF){
743 if (!SF->isExternal()) { // No body if function is external
744 Function *DF = cast<Function>(ValueMap[SF]); // Destination function
746 // DF not external SF external?
747 if (DF->isExternal()) {
748 // Only provide the function body if there isn't one already.
749 if (LinkFunctionBody(DF, SF, ValueMap, Err))
757 // LinkAppendingVars - If there were any appending global variables, link them
758 // together now. Return true on error.
760 static bool LinkAppendingVars(Module *M,
761 std::multimap<std::string, GlobalVariable *> &AppendingVars,
762 std::string *ErrorMsg) {
763 if (AppendingVars.empty()) return false; // Nothing to do.
765 // Loop over the multimap of appending vars, processing any variables with the
766 // same name, forming a new appending global variable with both of the
767 // initializers merged together, then rewrite references to the old variables
770 std::vector<Constant*> Inits;
771 while (AppendingVars.size() > 1) {
772 // Get the first two elements in the map...
773 std::multimap<std::string,
774 GlobalVariable*>::iterator Second = AppendingVars.begin(), First=Second++;
776 // If the first two elements are for different names, there is no pair...
777 // Otherwise there is a pair, so link them together...
778 if (First->first == Second->first) {
779 GlobalVariable *G1 = First->second, *G2 = Second->second;
780 const ArrayType *T1 = cast<ArrayType>(G1->getType()->getElementType());
781 const ArrayType *T2 = cast<ArrayType>(G2->getType()->getElementType());
783 // Check to see that they two arrays agree on type...
784 if (T1->getElementType() != T2->getElementType())
785 return Error(ErrorMsg,
786 "Appending variables with different element types need to be linked!");
787 if (G1->isConstant() != G2->isConstant())
788 return Error(ErrorMsg,
789 "Appending variables linked with different const'ness!");
791 unsigned NewSize = T1->getNumElements() + T2->getNumElements();
792 ArrayType *NewType = ArrayType::get(T1->getElementType(), NewSize);
794 // Create the new global variable...
796 new GlobalVariable(NewType, G1->isConstant(), G1->getLinkage(),
797 /*init*/0, First->first, M);
799 // Merge the initializer...
800 Inits.reserve(NewSize);
801 if (ConstantArray *I = dyn_cast<ConstantArray>(G1->getInitializer())) {
802 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i)
803 Inits.push_back(cast<Constant>(I->getValues()[i]));
805 assert(isa<ConstantAggregateZero>(G1->getInitializer()));
806 Constant *CV = Constant::getNullValue(T1->getElementType());
807 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i)
810 if (ConstantArray *I = dyn_cast<ConstantArray>(G2->getInitializer())) {
811 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i)
812 Inits.push_back(cast<Constant>(I->getValues()[i]));
814 assert(isa<ConstantAggregateZero>(G2->getInitializer()));
815 Constant *CV = Constant::getNullValue(T2->getElementType());
816 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i)
819 NG->setInitializer(ConstantArray::get(NewType, Inits));
822 // Replace any uses of the two global variables with uses of the new
825 // FIXME: This should rewrite simple/straight-forward uses such as
826 // getelementptr instructions to not use the Cast!
827 G1->replaceAllUsesWith(ConstantExpr::getCast(NG, G1->getType()));
828 G2->replaceAllUsesWith(ConstantExpr::getCast(NG, G2->getType()));
830 // Remove the two globals from the module now...
831 M->getGlobalList().erase(G1);
832 M->getGlobalList().erase(G2);
834 // Put the new global into the AppendingVars map so that we can handle
835 // linking of more than two vars...
838 AppendingVars.erase(First);
845 // LinkModules - This function links two modules together, with the resulting
846 // left module modified to be the composite of the two input modules. If an
847 // error occurs, true is returned and ErrorMsg (if not null) is set to indicate
848 // the problem. Upon failure, the Dest module could be in a modified state, and
849 // shouldn't be relied on to be consistent.
851 bool llvm::LinkModules(Module *Dest, const Module *Src, std::string *ErrorMsg) {
852 if (Dest->getEndianness() == Module::AnyEndianness)
853 Dest->setEndianness(Src->getEndianness());
854 if (Dest->getPointerSize() == Module::AnyPointerSize)
855 Dest->setPointerSize(Src->getPointerSize());
857 if (Src->getEndianness() != Module::AnyEndianness &&
858 Dest->getEndianness() != Src->getEndianness())
859 std::cerr << "WARNING: Linking two modules of different endianness!\n";
860 if (Src->getPointerSize() != Module::AnyPointerSize &&
861 Dest->getPointerSize() != Src->getPointerSize())
862 std::cerr << "WARNING: Linking two modules of different pointer size!\n";
864 // LinkTypes - Go through the symbol table of the Src module and see if any
865 // types are named in the src module that are not named in the Dst module.
866 // Make sure there are no type name conflicts.
868 if (LinkTypes(Dest, Src, ErrorMsg)) return true;
870 // ValueMap - Mapping of values from what they used to be in Src, to what they
873 std::map<const Value*, Value*> ValueMap;
875 // AppendingVars - Keep track of global variables in the destination module
876 // with appending linkage. After the module is linked together, they are
877 // appended and the module is rewritten.
879 std::multimap<std::string, GlobalVariable *> AppendingVars;
881 // Add all of the appending globals already in the Dest module to
883 for (Module::giterator I = Dest->gbegin(), E = Dest->gend(); I != E; ++I)
884 if (I->hasAppendingLinkage())
885 AppendingVars.insert(std::make_pair(I->getName(), I));
887 // Insert all of the globals in src into the Dest module... without linking
888 // initializers (which could refer to functions not yet mapped over).
890 if (LinkGlobals(Dest, Src, ValueMap, AppendingVars, ErrorMsg)) return true;
892 // Link the functions together between the two modules, without doing function
893 // bodies... this just adds external function prototypes to the Dest
894 // function... We do this so that when we begin processing function bodies,
895 // all of the global values that may be referenced are available in our
898 if (LinkFunctionProtos(Dest, Src, ValueMap, ErrorMsg)) return true;
900 // Update the initializers in the Dest module now that all globals that may
901 // be referenced are in Dest.
903 if (LinkGlobalInits(Dest, Src, ValueMap, ErrorMsg)) return true;
905 // Link in the function bodies that are defined in the source module into the
906 // DestModule. This consists basically of copying the function over and
907 // fixing up references to values.
909 if (LinkFunctionBodies(Dest, Src, ValueMap, ErrorMsg)) return true;
911 // If there were any appending global variables, link them together now.
913 if (LinkAppendingVars(Dest, AppendingVars, ErrorMsg)) return true;