1 //===- Linker.cpp - Module Linker Implementation --------------------------===//
3 // This file implements the LLVM module linker.
6 // * Merges global variables between the two modules
7 // * Uninit + Uninit = Init, Init + Uninit = Init, Init + Init = Error if !=
8 // * Merges functions between two modules
10 //===----------------------------------------------------------------------===//
12 #include "llvm/Transforms/Utils/Linker.h"
13 #include "llvm/Module.h"
14 #include "llvm/SymbolTable.h"
15 #include "llvm/DerivedTypes.h"
16 #include "llvm/iOther.h"
17 #include "llvm/Constants.h"
19 // Error - Simple wrapper function to conditionally assign to E and return true.
20 // This just makes error return conditions a little bit simpler...
22 static inline bool Error(std::string *E, const std::string &Message) {
27 // ResolveTypes - Attempt to link the two specified types together. Return true
28 // if there is an error and they cannot yet be linked.
30 static bool ResolveTypes(const Type *DestTy, const Type *SrcTy,
31 SymbolTable *DestST, const std::string &Name) {
32 if (DestTy == SrcTy) return false; // If already equal, noop
34 // Does the type already exist in the module?
35 if (DestTy && !isa<OpaqueType>(DestTy)) { // Yup, the type already exists...
36 if (const OpaqueType *OT = dyn_cast<OpaqueType>(SrcTy)) {
37 const_cast<OpaqueType*>(OT)->refineAbstractTypeTo(DestTy);
39 return true; // Cannot link types... neither is opaque and not-equal
41 } else { // Type not in dest module. Add it now.
42 if (DestTy) // Type _is_ in module, just opaque...
43 const_cast<OpaqueType*>(cast<OpaqueType>(DestTy))
44 ->refineAbstractTypeTo(SrcTy);
45 else if (!Name.empty())
46 DestST->insert(Name, const_cast<Type*>(SrcTy));
51 static const FunctionType *getFT(const PATypeHolder &TH) {
52 return cast<FunctionType>(TH.get());
54 static const StructType *getST(const PATypeHolder &TH) {
55 return cast<StructType>(TH.get());
58 // RecursiveResolveTypes - This is just like ResolveTypes, except that it
59 // recurses down into derived types, merging the used types if the parent types
62 static bool RecursiveResolveTypesI(const PATypeHolder &DestTy,
63 const PATypeHolder &SrcTy,
64 SymbolTable *DestST, const std::string &Name,
65 std::vector<std::pair<PATypeHolder, PATypeHolder> > &Pointers) {
66 const Type *SrcTyT = SrcTy.get();
67 const Type *DestTyT = DestTy.get();
68 if (DestTyT == SrcTyT) return false; // If already equal, noop
70 // If we found our opaque type, resolve it now!
71 if (isa<OpaqueType>(DestTyT) || isa<OpaqueType>(SrcTyT))
72 return ResolveTypes(DestTyT, SrcTyT, DestST, Name);
74 // Two types cannot be resolved together if they are of different primitive
75 // type. For example, we cannot resolve an int to a float.
76 if (DestTyT->getPrimitiveID() != SrcTyT->getPrimitiveID()) return true;
78 // Otherwise, resolve the used type used by this derived type...
79 switch (DestTyT->getPrimitiveID()) {
80 case Type::FunctionTyID: {
81 if (cast<FunctionType>(DestTyT)->isVarArg() !=
82 cast<FunctionType>(SrcTyT)->isVarArg())
84 for (unsigned i = 0, e = getFT(DestTy)->getNumContainedTypes(); i != e; ++i)
85 if (RecursiveResolveTypesI(getFT(DestTy)->getContainedType(i),
86 getFT(SrcTy)->getContainedType(i), DestST, "",
91 case Type::StructTyID: {
92 if (getST(DestTy)->getNumContainedTypes() !=
93 getST(SrcTy)->getNumContainedTypes()) return 1;
94 for (unsigned i = 0, e = getST(DestTy)->getNumContainedTypes(); i != e; ++i)
95 if (RecursiveResolveTypesI(getST(DestTy)->getContainedType(i),
96 getST(SrcTy)->getContainedType(i), DestST, "",
101 case Type::ArrayTyID: {
102 const ArrayType *DAT = cast<ArrayType>(DestTy.get());
103 const ArrayType *SAT = cast<ArrayType>(SrcTy.get());
104 if (DAT->getNumElements() != SAT->getNumElements()) return true;
105 return RecursiveResolveTypesI(DAT->getElementType(), SAT->getElementType(),
106 DestST, "", Pointers);
108 case Type::PointerTyID: {
109 // If this is a pointer type, check to see if we have already seen it. If
110 // so, we are in a recursive branch. Cut off the search now. We cannot use
111 // an associative container for this search, because the type pointers (keys
112 // in the container) change whenever types get resolved...
114 for (unsigned i = 0, e = Pointers.size(); i != e; ++i)
115 if (Pointers[i].first == DestTy)
116 return Pointers[i].second != SrcTy;
118 // Otherwise, add the current pointers to the vector to stop recursion on
120 Pointers.push_back(std::make_pair(DestTyT, SrcTyT));
122 RecursiveResolveTypesI(cast<PointerType>(DestTy.get())->getElementType(),
123 cast<PointerType>(SrcTy.get())->getElementType(),
124 DestST, "", Pointers);
128 default: assert(0 && "Unexpected type!"); return true;
132 static bool RecursiveResolveTypes(const PATypeHolder &DestTy,
133 const PATypeHolder &SrcTy,
134 SymbolTable *DestST, const std::string &Name){
135 std::vector<std::pair<PATypeHolder, PATypeHolder> > PointerTypes;
136 return RecursiveResolveTypesI(DestTy, SrcTy, DestST, Name, PointerTypes);
140 // LinkTypes - Go through the symbol table of the Src module and see if any
141 // types are named in the src module that are not named in the Dst module.
142 // Make sure there are no type name conflicts.
144 static bool LinkTypes(Module *Dest, const Module *Src, std::string *Err) {
145 SymbolTable *DestST = &Dest->getSymbolTable();
146 const SymbolTable *SrcST = &Src->getSymbolTable();
148 // Look for a type plane for Type's...
149 SymbolTable::const_iterator PI = SrcST->find(Type::TypeTy);
150 if (PI == SrcST->end()) return false; // No named types, do nothing.
152 // Some types cannot be resolved immediately becuse they depend on other types
153 // being resolved to each other first. This contains a list of types we are
154 // waiting to recheck.
155 std::vector<std::string> DelayedTypesToResolve;
157 const SymbolTable::VarMap &VM = PI->second;
158 for (SymbolTable::type_const_iterator I = VM.begin(), E = VM.end();
160 const std::string &Name = I->first;
161 Type *RHS = cast<Type>(I->second);
163 // Check to see if this type name is already in the dest module...
164 Type *Entry = cast_or_null<Type>(DestST->lookup(Type::TypeTy, Name));
166 if (ResolveTypes(Entry, RHS, DestST, Name)) {
167 // They look different, save the types 'till later to resolve.
168 DelayedTypesToResolve.push_back(Name);
172 // Iteratively resolve types while we can...
173 while (!DelayedTypesToResolve.empty()) {
174 // Loop over all of the types, attempting to resolve them if possible...
175 unsigned OldSize = DelayedTypesToResolve.size();
177 // Try direct resolution by name...
178 for (unsigned i = 0; i != DelayedTypesToResolve.size(); ++i) {
179 const std::string &Name = DelayedTypesToResolve[i];
180 Type *T1 = cast<Type>(VM.find(Name)->second);
181 Type *T2 = cast<Type>(DestST->lookup(Type::TypeTy, Name));
182 if (!ResolveTypes(T2, T1, DestST, Name)) {
183 // We are making progress!
184 DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i);
189 // Did we not eliminate any types?
190 if (DelayedTypesToResolve.size() == OldSize) {
191 // Attempt to resolve subelements of types. This allows us to merge these
192 // two types: { int* } and { opaque* }
193 for (unsigned i = 0, e = DelayedTypesToResolve.size(); i != e; ++i) {
194 const std::string &Name = DelayedTypesToResolve[i];
195 PATypeHolder T1(cast<Type>(VM.find(Name)->second));
196 PATypeHolder T2(cast<Type>(DestST->lookup(Type::TypeTy, Name)));
198 if (!RecursiveResolveTypes(T2, T1, DestST, Name)) {
199 // We are making progress!
200 DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i);
202 // Go back to the main loop, perhaps we can resolve directly by name
208 // If we STILL cannot resolve the types, then there is something wrong.
210 if (DelayedTypesToResolve.size() == OldSize) {
211 // Build up an error message of all of the mismatched types.
212 std::string ErrorMessage;
213 for (unsigned i = 0, e = DelayedTypesToResolve.size(); i != e; ++i) {
214 const std::string &Name = DelayedTypesToResolve[i];
215 const Type *T1 = cast<Type>(VM.find(Name)->second);
216 const Type *T2 = cast<Type>(DestST->lookup(Type::TypeTy, Name));
217 ErrorMessage += " Type named '" + Name +
218 "' conflicts.\n Src='" + T1->getDescription() +
219 "'.\n Dest='" + T2->getDescription() + "'\n";
221 return Error(Err, "Type conflict between types in modules:\n" +
231 static void PrintMap(const std::map<const Value*, Value*> &M) {
232 for (std::map<const Value*, Value*>::const_iterator I = M.begin(), E =M.end();
234 std::cerr << " Fr: " << (void*)I->first << " ";
236 std::cerr << " To: " << (void*)I->second << " ";
243 // RemapOperand - Use LocalMap and GlobalMap to convert references from one
244 // module to another. This is somewhat sophisticated in that it can
245 // automatically handle constant references correctly as well...
247 static Value *RemapOperand(const Value *In,
248 std::map<const Value*, Value*> &LocalMap,
249 std::map<const Value*, Value*> *GlobalMap) {
250 std::map<const Value*,Value*>::const_iterator I = LocalMap.find(In);
251 if (I != LocalMap.end()) return I->second;
254 I = GlobalMap->find(In);
255 if (I != GlobalMap->end()) return I->second;
258 // Check to see if it's a constant that we are interesting in transforming...
259 if (const Constant *CPV = dyn_cast<Constant>(In)) {
260 if (!isa<DerivedType>(CPV->getType()) && !isa<ConstantExpr>(CPV))
261 return const_cast<Constant*>(CPV); // Simple constants stay identical...
263 Constant *Result = 0;
265 if (const ConstantArray *CPA = dyn_cast<ConstantArray>(CPV)) {
266 const std::vector<Use> &Ops = CPA->getValues();
267 std::vector<Constant*> Operands(Ops.size());
268 for (unsigned i = 0, e = Ops.size(); i != e; ++i)
270 cast<Constant>(RemapOperand(Ops[i], LocalMap, GlobalMap));
271 Result = ConstantArray::get(cast<ArrayType>(CPA->getType()), Operands);
272 } else if (const ConstantStruct *CPS = dyn_cast<ConstantStruct>(CPV)) {
273 const std::vector<Use> &Ops = CPS->getValues();
274 std::vector<Constant*> Operands(Ops.size());
275 for (unsigned i = 0; i < Ops.size(); ++i)
277 cast<Constant>(RemapOperand(Ops[i], LocalMap, GlobalMap));
278 Result = ConstantStruct::get(cast<StructType>(CPS->getType()), Operands);
279 } else if (isa<ConstantPointerNull>(CPV)) {
280 Result = const_cast<Constant*>(CPV);
281 } else if (const ConstantPointerRef *CPR =
282 dyn_cast<ConstantPointerRef>(CPV)) {
283 Value *V = RemapOperand(CPR->getValue(), LocalMap, GlobalMap);
284 Result = ConstantPointerRef::get(cast<GlobalValue>(V));
285 } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CPV)) {
286 if (CE->getOpcode() == Instruction::GetElementPtr) {
287 Value *Ptr = RemapOperand(CE->getOperand(0), LocalMap, GlobalMap);
288 std::vector<Constant*> Indices;
289 Indices.reserve(CE->getNumOperands()-1);
290 for (unsigned i = 1, e = CE->getNumOperands(); i != e; ++i)
291 Indices.push_back(cast<Constant>(RemapOperand(CE->getOperand(i),
292 LocalMap, GlobalMap)));
294 Result = ConstantExpr::getGetElementPtr(cast<Constant>(Ptr), Indices);
295 } else if (CE->getNumOperands() == 1) {
297 assert(CE->getOpcode() == Instruction::Cast);
298 Value *V = RemapOperand(CE->getOperand(0), LocalMap, GlobalMap);
299 Result = ConstantExpr::getCast(cast<Constant>(V), CE->getType());
300 } else if (CE->getNumOperands() == 2) {
301 // Binary operator...
302 Value *V1 = RemapOperand(CE->getOperand(0), LocalMap, GlobalMap);
303 Value *V2 = RemapOperand(CE->getOperand(1), LocalMap, GlobalMap);
305 Result = ConstantExpr::get(CE->getOpcode(), cast<Constant>(V1),
308 assert(0 && "Unknown constant expr type!");
312 assert(0 && "Unknown type of derived type constant value!");
315 // Cache the mapping in our local map structure...
317 GlobalMap->insert(std::make_pair(In, Result));
319 LocalMap.insert(std::make_pair(In, Result));
323 std::cerr << "XXX LocalMap: \n";
327 std::cerr << "XXX GlobalMap: \n";
328 PrintMap(*GlobalMap);
331 std::cerr << "Couldn't remap value: " << (void*)In << " " << *In << "\n";
332 assert(0 && "Couldn't remap value!");
336 /// FindGlobalNamed - Look in the specified symbol table for a global with the
337 /// specified name and type. If an exactly matching global does not exist, see
338 /// if there is a global which is "type compatible" with the specified
339 /// name/type. This allows us to resolve things like '%x = global int*' with
340 /// '%x = global opaque*'.
342 static GlobalValue *FindGlobalNamed(const std::string &Name, const Type *Ty,
344 // See if an exact match exists in the symbol table...
345 if (Value *V = ST->lookup(Ty, Name)) return cast<GlobalValue>(V);
347 // It doesn't exist exactly, scan through all of the type planes in the symbol
348 // table, checking each of them for a type-compatible version.
350 for (SymbolTable::iterator I = ST->begin(), E = ST->end(); I != E; ++I)
351 if (I->first->getType() != Type::TypeTy) {
352 SymbolTable::VarMap &VM = I->second;
353 // Does this type plane contain an entry with the specified name?
354 SymbolTable::type_iterator TI = VM.find(Name);
355 if (TI != VM.end()) {
356 // Determine whether we can fold the two types together, resolving them.
357 // If so, we can use this value.
358 if (!RecursiveResolveTypes(Ty, I->first, ST, ""))
359 return cast<GlobalValue>(TI->second);
362 return 0; // Otherwise, nothing could be found.
366 // LinkGlobals - Loop through the global variables in the src module and merge
367 // them into the dest module.
369 static bool LinkGlobals(Module *Dest, const Module *Src,
370 std::map<const Value*, Value*> &ValueMap,
371 std::multimap<std::string, GlobalVariable *> &AppendingVars,
373 // We will need a module level symbol table if the src module has a module
374 // level symbol table...
375 SymbolTable *ST = (SymbolTable*)&Dest->getSymbolTable();
377 // Loop over all of the globals in the src module, mapping them over as we go
379 for (Module::const_giterator I = Src->gbegin(), E = Src->gend(); I != E; ++I){
380 const GlobalVariable *SGV = I;
381 GlobalVariable *DGV = 0;
382 if (SGV->hasName()) {
383 // A same named thing is a global variable, because the only two things
384 // that may be in a module level symbol table are Global Vars and
385 // Functions, and they both have distinct, nonoverlapping, possible types.
387 DGV = cast_or_null<GlobalVariable>(FindGlobalNamed(SGV->getName(),
388 SGV->getType(), ST));
391 assert(SGV->hasInitializer() || SGV->hasExternalLinkage() &&
392 "Global must either be external or have an initializer!");
394 bool SGExtern = SGV->isExternal();
395 bool DGExtern = DGV ? DGV->isExternal() : false;
397 if (!DGV || DGV->hasInternalLinkage() || SGV->hasInternalLinkage()) {
398 // No linking to be performed, simply create an identical version of the
399 // symbol over in the dest module... the initializer will be filled in
400 // later by LinkGlobalInits...
402 GlobalVariable *NewDGV =
403 new GlobalVariable(SGV->getType()->getElementType(),
404 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
405 SGV->getName(), Dest);
407 // If the LLVM runtime renamed the global, but it is an externally visible
408 // symbol, DGV must be an existing global with internal linkage. Rename
410 if (NewDGV->getName() != SGV->getName() && !NewDGV->hasInternalLinkage()){
411 assert(DGV && DGV->getName() == SGV->getName() &&
412 DGV->hasInternalLinkage());
414 NewDGV->setName(SGV->getName()); // Force the name back
415 DGV->setName(SGV->getName()); // This will cause a renaming
416 assert(NewDGV->getName() == SGV->getName() &&
417 DGV->getName() != SGV->getName());
420 // Make sure to remember this mapping...
421 ValueMap.insert(std::make_pair(SGV, NewDGV));
422 if (SGV->hasAppendingLinkage())
423 // Keep track that this is an appending variable...
424 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV));
426 } else if (SGV->isExternal()) {
427 // If SGV is external or if both SGV & DGV are external.. Just link the
428 // external globals, we aren't adding anything.
429 ValueMap.insert(std::make_pair(SGV, DGV));
431 } else if (DGV->isExternal()) { // If DGV is external but SGV is not...
432 ValueMap.insert(std::make_pair(SGV, DGV));
433 DGV->setLinkage(SGV->getLinkage()); // Inherit linkage!
434 } else if (SGV->getLinkage() != DGV->getLinkage()) {
435 return Error(Err, "Global variables named '" + SGV->getName() +
436 "' have different linkage specifiers!");
437 } else if (SGV->hasExternalLinkage()) {
438 // Allow linking two exactly identical external global variables...
439 if (SGV->isConstant() != DGV->isConstant() ||
440 SGV->getInitializer() != DGV->getInitializer())
441 return Error(Err, "Global Variable Collision on '" +
442 SGV->getType()->getDescription() + " %" + SGV->getName() +
443 "' - Global variables differ in const'ness");
444 ValueMap.insert(std::make_pair(SGV, DGV));
445 } else if (SGV->hasLinkOnceLinkage()) {
446 // If the global variable has a name, and that name is already in use in
447 // the Dest module, make sure that the name is a compatible global
450 // Check to see if the two GV's have the same Const'ness...
451 if (SGV->isConstant() != DGV->isConstant())
452 return Error(Err, "Global Variable Collision on '" +
453 SGV->getType()->getDescription() + " %" + SGV->getName() +
454 "' - Global variables differ in const'ness");
456 // Okay, everything is cool, remember the mapping...
457 ValueMap.insert(std::make_pair(SGV, DGV));
458 } else if (SGV->hasAppendingLinkage()) {
459 // No linking is performed yet. Just insert a new copy of the global, and
460 // keep track of the fact that it is an appending variable in the
461 // AppendingVars map. The name is cleared out so that no linkage is
463 GlobalVariable *NewDGV =
464 new GlobalVariable(SGV->getType()->getElementType(),
465 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
468 // Make sure to remember this mapping...
469 ValueMap.insert(std::make_pair(SGV, NewDGV));
471 // Keep track that this is an appending variable...
472 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV));
474 assert(0 && "Unknown linkage!");
481 // LinkGlobalInits - Update the initializers in the Dest module now that all
482 // globals that may be referenced are in Dest.
484 static bool LinkGlobalInits(Module *Dest, const Module *Src,
485 std::map<const Value*, Value*> &ValueMap,
488 // Loop over all of the globals in the src module, mapping them over as we go
490 for (Module::const_giterator I = Src->gbegin(), E = Src->gend(); I != E; ++I){
491 const GlobalVariable *SGV = I;
493 if (SGV->hasInitializer()) { // Only process initialized GV's
494 // Figure out what the initializer looks like in the dest module...
496 cast<Constant>(RemapOperand(SGV->getInitializer(), ValueMap, 0));
498 GlobalVariable *DGV = cast<GlobalVariable>(ValueMap[SGV]);
499 if (DGV->hasInitializer()) {
500 assert(SGV->getLinkage() == DGV->getLinkage());
501 if (SGV->hasExternalLinkage()) {
502 if (DGV->getInitializer() != SInit)
503 return Error(Err, "Global Variable Collision on '" +
504 SGV->getType()->getDescription() +"':%"+SGV->getName()+
505 " - Global variables have different initializers");
506 } else if (DGV->hasLinkOnceLinkage()) {
507 // Nothing is required, mapped values will take the new global
509 } else if (DGV->hasAppendingLinkage()) {
510 assert(0 && "Appending linkage unimplemented!");
512 assert(0 && "Unknown linkage!");
515 // Copy the initializer over now...
516 DGV->setInitializer(SInit);
523 // LinkFunctionProtos - Link the functions together between the two modules,
524 // without doing function bodies... this just adds external function prototypes
525 // to the Dest function...
527 static bool LinkFunctionProtos(Module *Dest, const Module *Src,
528 std::map<const Value*, Value*> &ValueMap,
530 SymbolTable *ST = (SymbolTable*)&Dest->getSymbolTable();
532 // Loop over all of the functions in the src module, mapping them over as we
535 for (Module::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) {
536 const Function *SF = I; // SrcFunction
539 // The same named thing is a Function, because the only two things
540 // that may be in a module level symbol table are Global Vars and
541 // Functions, and they both have distinct, nonoverlapping, possible types.
543 DF = cast_or_null<Function>(FindGlobalNamed(SF->getName(), SF->getType(),
546 if (!DF || SF->hasInternalLinkage() || DF->hasInternalLinkage()) {
547 // Function does not already exist, simply insert an function signature
548 // identical to SF into the dest module...
549 Function *NewDF = new Function(SF->getFunctionType(), SF->getLinkage(),
550 SF->getName(), Dest);
552 // If the LLVM runtime renamed the function, but it is an externally
553 // visible symbol, DF must be an existing function with internal linkage.
555 if (NewDF->getName() != SF->getName() && !NewDF->hasInternalLinkage()) {
556 assert(DF && DF->getName() == SF->getName() &&DF->hasInternalLinkage());
558 NewDF->setName(SF->getName()); // Force the name back
559 DF->setName(SF->getName()); // This will cause a renaming
560 assert(NewDF->getName() == SF->getName() &&
561 DF->getName() != SF->getName());
564 // ... and remember this mapping...
565 ValueMap.insert(std::make_pair(SF, NewDF));
566 } else if (SF->isExternal()) {
567 // If SF is external or if both SF & DF are external.. Just link the
568 // external functions, we aren't adding anything.
569 ValueMap.insert(std::make_pair(SF, DF));
570 } else if (DF->isExternal()) { // If DF is external but SF is not...
571 // Link the external functions, update linkage qualifiers
572 ValueMap.insert(std::make_pair(SF, DF));
573 DF->setLinkage(SF->getLinkage());
575 } else if (SF->getLinkage() != DF->getLinkage()) {
576 return Error(Err, "Functions named '" + SF->getName() +
577 "' have different linkage specifiers!");
578 } else if (SF->hasExternalLinkage()) {
579 // The function is defined in both modules!!
580 return Error(Err, "Function '" +
581 SF->getFunctionType()->getDescription() + "':\"" +
582 SF->getName() + "\" - Function is already defined!");
583 } else if (SF->hasLinkOnceLinkage()) {
584 // Completely ignore the source function.
585 ValueMap.insert(std::make_pair(SF, DF));
587 assert(0 && "Unknown linkage configuration found!");
593 // LinkFunctionBody - Copy the source function over into the dest function and
594 // fix up references to values. At this point we know that Dest is an external
595 // function, and that Src is not.
597 static bool LinkFunctionBody(Function *Dest, const Function *Src,
598 std::map<const Value*, Value*> &GlobalMap,
600 assert(Src && Dest && Dest->isExternal() && !Src->isExternal());
601 std::map<const Value*, Value*> LocalMap; // Map for function local values
603 // Go through and convert function arguments over...
604 Function::aiterator DI = Dest->abegin();
605 for (Function::const_aiterator I = Src->abegin(), E = Src->aend();
607 DI->setName(I->getName()); // Copy the name information over...
609 // Add a mapping to our local map
610 LocalMap.insert(std::make_pair(I, DI));
613 // Loop over all of the basic blocks, copying the instructions over...
615 for (Function::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) {
616 // Create new basic block and add to mapping and the Dest function...
617 BasicBlock *DBB = new BasicBlock(I->getName(), Dest);
618 LocalMap.insert(std::make_pair(I, DBB));
620 // Loop over all of the instructions in the src basic block, copying them
621 // over. Note that this is broken in a strict sense because the cloned
622 // instructions will still be referencing values in the Src module, not
623 // the remapped values. In our case, however, we will not get caught and
624 // so we can delay patching the values up until later...
626 for (BasicBlock::const_iterator II = I->begin(), IE = I->end();
628 Instruction *DI = II->clone();
629 DI->setName(II->getName());
630 DBB->getInstList().push_back(DI);
631 LocalMap.insert(std::make_pair(II, DI));
635 // At this point, all of the instructions and values of the function are now
636 // copied over. The only problem is that they are still referencing values in
637 // the Source function as operands. Loop through all of the operands of the
638 // functions and patch them up to point to the local versions...
640 for (Function::iterator BB = Dest->begin(), BE = Dest->end(); BB != BE; ++BB)
641 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
642 for (Instruction::op_iterator OI = I->op_begin(), OE = I->op_end();
644 *OI = RemapOperand(*OI, LocalMap, &GlobalMap);
650 // LinkFunctionBodies - Link in the function bodies that are defined in the
651 // source module into the DestModule. This consists basically of copying the
652 // function over and fixing up references to values.
654 static bool LinkFunctionBodies(Module *Dest, const Module *Src,
655 std::map<const Value*, Value*> &ValueMap,
658 // Loop over all of the functions in the src module, mapping them over as we
661 for (Module::const_iterator SF = Src->begin(), E = Src->end(); SF != E; ++SF){
662 if (!SF->isExternal()) { // No body if function is external
663 Function *DF = cast<Function>(ValueMap[SF]); // Destination function
665 // DF not external SF external?
666 if (!DF->isExternal()) {
667 if (DF->hasLinkOnceLinkage()) continue; // No relinkage for link-once!
669 *Err = "Function '" + (SF->hasName() ? SF->getName() :std::string(""))
670 + "' body multiply defined!";
674 if (LinkFunctionBody(DF, SF, ValueMap, Err)) return true;
680 // LinkAppendingVars - If there were any appending global variables, link them
681 // together now. Return true on error.
683 static bool LinkAppendingVars(Module *M,
684 std::multimap<std::string, GlobalVariable *> &AppendingVars,
685 std::string *ErrorMsg) {
686 if (AppendingVars.empty()) return false; // Nothing to do.
688 // Loop over the multimap of appending vars, processing any variables with the
689 // same name, forming a new appending global variable with both of the
690 // initializers merged together, then rewrite references to the old variables
693 std::vector<Constant*> Inits;
694 while (AppendingVars.size() > 1) {
695 // Get the first two elements in the map...
696 std::multimap<std::string,
697 GlobalVariable*>::iterator Second = AppendingVars.begin(), First=Second++;
699 // If the first two elements are for different names, there is no pair...
700 // Otherwise there is a pair, so link them together...
701 if (First->first == Second->first) {
702 GlobalVariable *G1 = First->second, *G2 = Second->second;
703 const ArrayType *T1 = cast<ArrayType>(G1->getType()->getElementType());
704 const ArrayType *T2 = cast<ArrayType>(G2->getType()->getElementType());
706 // Check to see that they two arrays agree on type...
707 if (T1->getElementType() != T2->getElementType())
708 return Error(ErrorMsg,
709 "Appending variables with different element types need to be linked!");
710 if (G1->isConstant() != G2->isConstant())
711 return Error(ErrorMsg,
712 "Appending variables linked with different const'ness!");
714 unsigned NewSize = T1->getNumElements() + T2->getNumElements();
715 ArrayType *NewType = ArrayType::get(T1->getElementType(), NewSize);
717 // Create the new global variable...
719 new GlobalVariable(NewType, G1->isConstant(), G1->getLinkage(),
720 /*init*/0, First->first, M);
722 // Merge the initializer...
723 Inits.reserve(NewSize);
724 ConstantArray *I = cast<ConstantArray>(G1->getInitializer());
725 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i)
726 Inits.push_back(cast<Constant>(I->getValues()[i]));
727 I = cast<ConstantArray>(G2->getInitializer());
728 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i)
729 Inits.push_back(cast<Constant>(I->getValues()[i]));
730 NG->setInitializer(ConstantArray::get(NewType, Inits));
733 // Replace any uses of the two global variables with uses of the new
736 // FIXME: This should rewrite simple/straight-forward uses such as
737 // getelementptr instructions to not use the Cast!
738 ConstantPointerRef *NGCP = ConstantPointerRef::get(NG);
739 G1->replaceAllUsesWith(ConstantExpr::getCast(NGCP, G1->getType()));
740 G2->replaceAllUsesWith(ConstantExpr::getCast(NGCP, G2->getType()));
742 // Remove the two globals from the module now...
743 M->getGlobalList().erase(G1);
744 M->getGlobalList().erase(G2);
746 // Put the new global into the AppendingVars map so that we can handle
747 // linking of more than two vars...
750 AppendingVars.erase(First);
757 // LinkModules - This function links two modules together, with the resulting
758 // left module modified to be the composite of the two input modules. If an
759 // error occurs, true is returned and ErrorMsg (if not null) is set to indicate
760 // the problem. Upon failure, the Dest module could be in a modified state, and
761 // shouldn't be relied on to be consistent.
763 bool LinkModules(Module *Dest, const Module *Src, std::string *ErrorMsg) {
764 if (Dest->getEndianness() != Src->getEndianness())
765 std::cerr << "WARNING: Linking two modules of different endianness!\n";
766 if (Dest->getPointerSize() != Src->getPointerSize())
767 std::cerr << "WARNING: Linking two modules of different pointer size!\n";
769 // LinkTypes - Go through the symbol table of the Src module and see if any
770 // types are named in the src module that are not named in the Dst module.
771 // Make sure there are no type name conflicts.
773 if (LinkTypes(Dest, Src, ErrorMsg)) return true;
775 // ValueMap - Mapping of values from what they used to be in Src, to what they
778 std::map<const Value*, Value*> ValueMap;
780 // AppendingVars - Keep track of global variables in the destination module
781 // with appending linkage. After the module is linked together, they are
782 // appended and the module is rewritten.
784 std::multimap<std::string, GlobalVariable *> AppendingVars;
786 // Add all of the appending globals already in the Dest module to
788 for (Module::giterator I = Dest->gbegin(), E = Dest->gend(); I != E; ++I)
789 if (I->hasAppendingLinkage())
790 AppendingVars.insert(std::make_pair(I->getName(), I));
792 // Insert all of the globals in src into the Dest module... without linking
793 // initializers (which could refer to functions not yet mapped over).
795 if (LinkGlobals(Dest, Src, ValueMap, AppendingVars, ErrorMsg)) return true;
797 // Link the functions together between the two modules, without doing function
798 // bodies... this just adds external function prototypes to the Dest
799 // function... We do this so that when we begin processing function bodies,
800 // all of the global values that may be referenced are available in our
803 if (LinkFunctionProtos(Dest, Src, ValueMap, ErrorMsg)) return true;
805 // Update the initializers in the Dest module now that all globals that may
806 // be referenced are in Dest.
808 if (LinkGlobalInits(Dest, Src, ValueMap, ErrorMsg)) return true;
810 // Link in the function bodies that are defined in the source module into the
811 // DestModule. This consists basically of copying the function over and
812 // fixing up references to values.
814 if (LinkFunctionBodies(Dest, Src, ValueMap, ErrorMsg)) return true;
816 // If there were any appending global variables, link them together now.
818 if (LinkAppendingVars(Dest, AppendingVars, ErrorMsg)) return true;