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(Type *DestTy, Type *SrcTy, SymbolTable *DestST,
31 const std::string &Name) {
32 // Does the type already exist in the module?
33 if (DestTy && !isa<OpaqueType>(DestTy)) { // Yup, the type already exists...
34 if (DestTy == SrcTy) return false; // If already equal, noop
35 if (OpaqueType *OT = dyn_cast<OpaqueType>(SrcTy)) {
36 OT->refineAbstractTypeTo(DestTy);
38 return true; // Cannot link types... neither is opaque and not-equal
40 } else { // Type not in dest module. Add it now.
41 if (DestTy) // Type _is_ in module, just opaque...
42 cast<OpaqueType>(DestTy)->refineAbstractTypeTo(SrcTy);
44 DestST->insert(Name, SrcTy);
49 // LinkTypes - Go through the symbol table of the Src module and see if any
50 // types are named in the src module that are not named in the Dst module.
51 // Make sure there are no type name conflicts.
53 static bool LinkTypes(Module *Dest, const Module *Src, std::string *Err) {
54 SymbolTable *DestST = &Dest->getSymbolTable();
55 const SymbolTable *SrcST = &Src->getSymbolTable();
57 // Look for a type plane for Type's...
58 SymbolTable::const_iterator PI = SrcST->find(Type::TypeTy);
59 if (PI == SrcST->end()) return false; // No named types, do nothing.
61 // Some types cannot be resolved immediately becuse they depend on other types
62 // being resolved to each other first. This contains a list of types we are
63 // waiting to recheck.
64 std::vector<std::string> DelayedTypesToResolve;
66 const SymbolTable::VarMap &VM = PI->second;
67 for (SymbolTable::type_const_iterator I = VM.begin(), E = VM.end();
69 const std::string &Name = I->first;
70 Type *RHS = cast<Type>(I->second);
72 // Check to see if this type name is already in the dest module...
73 Type *Entry = cast_or_null<Type>(DestST->lookup(Type::TypeTy, Name));
75 if (ResolveTypes(Entry, RHS, DestST, Name)) {
76 // They look different, save the types 'till later to resolve.
77 DelayedTypesToResolve.push_back(Name);
81 // Iteratively resolve types while we can...
82 while (!DelayedTypesToResolve.empty()) {
83 // Loop over all of the types, attempting to resolve them if possible...
84 unsigned OldSize = DelayedTypesToResolve.size();
86 for (unsigned i = 0; i != DelayedTypesToResolve.size(); ++i) {
87 const std::string &Name = DelayedTypesToResolve[i];
88 Type *T1 = cast<Type>(VM.find(Name)->second);
89 Type *T2 = cast<Type>(DestST->lookup(Type::TypeTy, Name));
90 if (!ResolveTypes(T2, T1, DestST, Name)) {
91 // We are making progress!
92 DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i);
97 // Did we not eliminate any types?
98 if (DelayedTypesToResolve.size() == OldSize) {
99 // Build up an error message of all of the mismatched types.
100 std::string ErrorMessage;
101 for (unsigned i = 0, e = DelayedTypesToResolve.size(); i != e; ++i) {
102 const std::string &Name = DelayedTypesToResolve[i];
103 const Type *T1 = cast<Type>(VM.find(Name)->second);
104 const Type *T2 = cast<Type>(DestST->lookup(Type::TypeTy, Name));
105 ErrorMessage += " Type named '" + Name +
106 "' conflicts.\n Src='" + T1->getDescription() +
107 "'.\n Dest='" + T2->getDescription() + "'\n";
109 return Error(Err, "Type conflict between types in modules:\n" +
118 static void PrintMap(const std::map<const Value*, Value*> &M) {
119 for (std::map<const Value*, Value*>::const_iterator I = M.begin(), E =M.end();
121 std::cerr << " Fr: " << (void*)I->first << " ";
123 std::cerr << " To: " << (void*)I->second << " ";
130 // RemapOperand - Use LocalMap and GlobalMap to convert references from one
131 // module to another. This is somewhat sophisticated in that it can
132 // automatically handle constant references correctly as well...
134 static Value *RemapOperand(const Value *In,
135 std::map<const Value*, Value*> &LocalMap,
136 std::map<const Value*, Value*> *GlobalMap) {
137 std::map<const Value*,Value*>::const_iterator I = LocalMap.find(In);
138 if (I != LocalMap.end()) return I->second;
141 I = GlobalMap->find(In);
142 if (I != GlobalMap->end()) return I->second;
145 // Check to see if it's a constant that we are interesting in transforming...
146 if (const Constant *CPV = dyn_cast<Constant>(In)) {
147 if (!isa<DerivedType>(CPV->getType()) && !isa<ConstantExpr>(CPV))
148 return const_cast<Constant*>(CPV); // Simple constants stay identical...
150 Constant *Result = 0;
152 if (const ConstantArray *CPA = dyn_cast<ConstantArray>(CPV)) {
153 const std::vector<Use> &Ops = CPA->getValues();
154 std::vector<Constant*> Operands(Ops.size());
155 for (unsigned i = 0, e = Ops.size(); i != e; ++i)
157 cast<Constant>(RemapOperand(Ops[i], LocalMap, GlobalMap));
158 Result = ConstantArray::get(cast<ArrayType>(CPA->getType()), Operands);
159 } else if (const ConstantStruct *CPS = dyn_cast<ConstantStruct>(CPV)) {
160 const std::vector<Use> &Ops = CPS->getValues();
161 std::vector<Constant*> Operands(Ops.size());
162 for (unsigned i = 0; i < Ops.size(); ++i)
164 cast<Constant>(RemapOperand(Ops[i], LocalMap, GlobalMap));
165 Result = ConstantStruct::get(cast<StructType>(CPS->getType()), Operands);
166 } else if (isa<ConstantPointerNull>(CPV)) {
167 Result = const_cast<Constant*>(CPV);
168 } else if (const ConstantPointerRef *CPR =
169 dyn_cast<ConstantPointerRef>(CPV)) {
170 Value *V = RemapOperand(CPR->getValue(), LocalMap, GlobalMap);
171 Result = ConstantPointerRef::get(cast<GlobalValue>(V));
172 } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CPV)) {
173 if (CE->getOpcode() == Instruction::GetElementPtr) {
174 Value *Ptr = RemapOperand(CE->getOperand(0), LocalMap, GlobalMap);
175 std::vector<Constant*> Indices;
176 Indices.reserve(CE->getNumOperands()-1);
177 for (unsigned i = 1, e = CE->getNumOperands(); i != e; ++i)
178 Indices.push_back(cast<Constant>(RemapOperand(CE->getOperand(i),
179 LocalMap, GlobalMap)));
181 Result = ConstantExpr::getGetElementPtr(cast<Constant>(Ptr), Indices);
182 } else if (CE->getNumOperands() == 1) {
184 assert(CE->getOpcode() == Instruction::Cast);
185 Value *V = RemapOperand(CE->getOperand(0), LocalMap, GlobalMap);
186 Result = ConstantExpr::getCast(cast<Constant>(V), CE->getType());
187 } else if (CE->getNumOperands() == 2) {
188 // Binary operator...
189 Value *V1 = RemapOperand(CE->getOperand(0), LocalMap, GlobalMap);
190 Value *V2 = RemapOperand(CE->getOperand(1), LocalMap, GlobalMap);
192 Result = ConstantExpr::get(CE->getOpcode(), cast<Constant>(V1),
195 assert(0 && "Unknown constant expr type!");
199 assert(0 && "Unknown type of derived type constant value!");
202 // Cache the mapping in our local map structure...
204 GlobalMap->insert(std::make_pair(In, Result));
206 LocalMap.insert(std::make_pair(In, Result));
210 std::cerr << "XXX LocalMap: \n";
214 std::cerr << "XXX GlobalMap: \n";
215 PrintMap(*GlobalMap);
218 std::cerr << "Couldn't remap value: " << (void*)In << " " << *In << "\n";
219 assert(0 && "Couldn't remap value!");
224 // LinkGlobals - Loop through the global variables in the src module and merge
225 // them into the dest module.
227 static bool LinkGlobals(Module *Dest, const Module *Src,
228 std::map<const Value*, Value*> &ValueMap,
229 std::multimap<std::string, GlobalVariable *> &AppendingVars,
231 // We will need a module level symbol table if the src module has a module
232 // level symbol table...
233 SymbolTable *ST = (SymbolTable*)&Dest->getSymbolTable();
235 // Loop over all of the globals in the src module, mapping them over as we go
237 for (Module::const_giterator I = Src->gbegin(), E = Src->gend(); I != E; ++I){
238 const GlobalVariable *SGV = I;
239 GlobalVariable *DGV = 0;
240 if (SGV->hasName()) {
241 // A same named thing is a global variable, because the only two things
242 // that may be in a module level symbol table are Global Vars and
243 // Functions, and they both have distinct, nonoverlapping, possible types.
245 DGV = cast_or_null<GlobalVariable>(ST->lookup(SGV->getType(),
249 assert(SGV->hasInitializer() || SGV->hasExternalLinkage() &&
250 "Global must either be external or have an initializer!");
252 bool SGExtern = SGV->isExternal();
253 bool DGExtern = DGV ? DGV->isExternal() : false;
255 if (!DGV || DGV->hasInternalLinkage() || SGV->hasInternalLinkage()) {
256 // No linking to be performed, simply create an identical version of the
257 // symbol over in the dest module... the initializer will be filled in
258 // later by LinkGlobalInits...
260 GlobalVariable *NewDGV =
261 new GlobalVariable(SGV->getType()->getElementType(),
262 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
263 SGV->getName(), Dest);
265 // If the LLVM runtime renamed the global, but it is an externally visible
266 // symbol, DGV must be an existing global with internal linkage. Rename
268 if (NewDGV->getName() != SGV->getName() && !NewDGV->hasInternalLinkage()){
269 assert(DGV && DGV->getName() == SGV->getName() &&
270 DGV->hasInternalLinkage());
272 NewDGV->setName(SGV->getName()); // Force the name back
273 DGV->setName(SGV->getName()); // This will cause a renaming
274 assert(NewDGV->getName() == SGV->getName() &&
275 DGV->getName() != SGV->getName());
278 // Make sure to remember this mapping...
279 ValueMap.insert(std::make_pair(SGV, NewDGV));
280 if (SGV->hasAppendingLinkage())
281 // Keep track that this is an appending variable...
282 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV));
284 } else if (SGV->isExternal()) {
285 // If SGV is external or if both SGV & DGV are external.. Just link the
286 // external globals, we aren't adding anything.
287 ValueMap.insert(std::make_pair(SGV, DGV));
289 } else if (DGV->isExternal()) { // If DGV is external but SGV is not...
290 ValueMap.insert(std::make_pair(SGV, DGV));
291 DGV->setLinkage(SGV->getLinkage()); // Inherit linkage!
292 } else if (SGV->getLinkage() != DGV->getLinkage()) {
293 return Error(Err, "Global variables named '" + SGV->getName() +
294 "' have different linkage specifiers!");
295 } else if (SGV->hasExternalLinkage()) {
296 // Allow linking two exactly identical external global variables...
297 if (SGV->isConstant() != DGV->isConstant() ||
298 SGV->getInitializer() != DGV->getInitializer())
299 return Error(Err, "Global Variable Collision on '" +
300 SGV->getType()->getDescription() + " %" + SGV->getName() +
301 "' - Global variables differ in const'ness");
302 ValueMap.insert(std::make_pair(SGV, DGV));
303 } else if (SGV->hasLinkOnceLinkage()) {
304 // If the global variable has a name, and that name is already in use in
305 // the Dest module, make sure that the name is a compatible global
308 // Check to see if the two GV's have the same Const'ness...
309 if (SGV->isConstant() != DGV->isConstant())
310 return Error(Err, "Global Variable Collision on '" +
311 SGV->getType()->getDescription() + " %" + SGV->getName() +
312 "' - Global variables differ in const'ness");
314 // Okay, everything is cool, remember the mapping...
315 ValueMap.insert(std::make_pair(SGV, DGV));
316 } else if (SGV->hasAppendingLinkage()) {
317 // No linking is performed yet. Just insert a new copy of the global, and
318 // keep track of the fact that it is an appending variable in the
319 // AppendingVars map. The name is cleared out so that no linkage is
321 GlobalVariable *NewDGV =
322 new GlobalVariable(SGV->getType()->getElementType(),
323 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
326 // Make sure to remember this mapping...
327 ValueMap.insert(std::make_pair(SGV, NewDGV));
329 // Keep track that this is an appending variable...
330 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV));
332 assert(0 && "Unknown linkage!");
339 // LinkGlobalInits - Update the initializers in the Dest module now that all
340 // globals that may be referenced are in Dest.
342 static bool LinkGlobalInits(Module *Dest, const Module *Src,
343 std::map<const Value*, Value*> &ValueMap,
346 // Loop over all of the globals in the src module, mapping them over as we go
348 for (Module::const_giterator I = Src->gbegin(), E = Src->gend(); I != E; ++I){
349 const GlobalVariable *SGV = I;
351 if (SGV->hasInitializer()) { // Only process initialized GV's
352 // Figure out what the initializer looks like in the dest module...
354 cast<Constant>(RemapOperand(SGV->getInitializer(), ValueMap, 0));
356 GlobalVariable *DGV = cast<GlobalVariable>(ValueMap[SGV]);
357 if (DGV->hasInitializer()) {
358 assert(SGV->getLinkage() == DGV->getLinkage());
359 if (SGV->hasExternalLinkage()) {
360 if (DGV->getInitializer() != SInit)
361 return Error(Err, "Global Variable Collision on '" +
362 SGV->getType()->getDescription() +"':%"+SGV->getName()+
363 " - Global variables have different initializers");
364 } else if (DGV->hasLinkOnceLinkage()) {
365 // Nothing is required, mapped values will take the new global
367 } else if (DGV->hasAppendingLinkage()) {
368 assert(0 && "Appending linkage unimplemented!");
370 assert(0 && "Unknown linkage!");
373 // Copy the initializer over now...
374 DGV->setInitializer(SInit);
381 // LinkFunctionProtos - Link the functions together between the two modules,
382 // without doing function bodies... this just adds external function prototypes
383 // to the Dest function...
385 static bool LinkFunctionProtos(Module *Dest, const Module *Src,
386 std::map<const Value*, Value*> &ValueMap,
388 SymbolTable *ST = (SymbolTable*)&Dest->getSymbolTable();
390 // Loop over all of the functions in the src module, mapping them over as we
393 for (Module::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) {
394 const Function *SF = I; // SrcFunction
397 // The same named thing is a Function, because the only two things
398 // that may be in a module level symbol table are Global Vars and
399 // Functions, and they both have distinct, nonoverlapping, possible types.
401 DF = cast_or_null<Function>(ST->lookup(SF->getType(), SF->getName()));
403 if (!DF || SF->hasInternalLinkage() || DF->hasInternalLinkage()) {
404 // Function does not already exist, simply insert an function signature
405 // identical to SF into the dest module...
406 Function *NewDF = new Function(SF->getFunctionType(), SF->getLinkage(),
407 SF->getName(), Dest);
409 // If the LLVM runtime renamed the function, but it is an externally
410 // visible symbol, DF must be an existing function with internal linkage.
412 if (NewDF->getName() != SF->getName() && !NewDF->hasInternalLinkage()) {
413 assert(DF && DF->getName() == SF->getName() &&DF->hasInternalLinkage());
415 NewDF->setName(SF->getName()); // Force the name back
416 DF->setName(SF->getName()); // This will cause a renaming
417 assert(NewDF->getName() == SF->getName() &&
418 DF->getName() != SF->getName());
421 // ... and remember this mapping...
422 ValueMap.insert(std::make_pair(SF, NewDF));
423 } else if (SF->isExternal()) {
424 // If SF is external or if both SF & DF are external.. Just link the
425 // external functions, we aren't adding anything.
426 ValueMap.insert(std::make_pair(SF, DF));
427 } else if (DF->isExternal()) { // If DF is external but SF is not...
428 // Link the external functions, update linkage qualifiers
429 ValueMap.insert(std::make_pair(SF, DF));
430 DF->setLinkage(SF->getLinkage());
432 } else if (SF->getLinkage() != DF->getLinkage()) {
433 return Error(Err, "Functions named '" + SF->getName() +
434 "' have different linkage specifiers!");
435 } else if (SF->hasExternalLinkage()) {
436 // The function is defined in both modules!!
437 return Error(Err, "Function '" +
438 SF->getFunctionType()->getDescription() + "':\"" +
439 SF->getName() + "\" - Function is already defined!");
440 } else if (SF->hasLinkOnceLinkage()) {
441 // Completely ignore the source function.
442 ValueMap.insert(std::make_pair(SF, DF));
444 assert(0 && "Unknown linkage configuration found!");
450 // LinkFunctionBody - Copy the source function over into the dest function and
451 // fix up references to values. At this point we know that Dest is an external
452 // function, and that Src is not.
454 static bool LinkFunctionBody(Function *Dest, const Function *Src,
455 std::map<const Value*, Value*> &GlobalMap,
457 assert(Src && Dest && Dest->isExternal() && !Src->isExternal());
458 std::map<const Value*, Value*> LocalMap; // Map for function local values
460 // Go through and convert function arguments over...
461 Function::aiterator DI = Dest->abegin();
462 for (Function::const_aiterator I = Src->abegin(), E = Src->aend();
464 DI->setName(I->getName()); // Copy the name information over...
466 // Add a mapping to our local map
467 LocalMap.insert(std::make_pair(I, DI));
470 // Loop over all of the basic blocks, copying the instructions over...
472 for (Function::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) {
473 // Create new basic block and add to mapping and the Dest function...
474 BasicBlock *DBB = new BasicBlock(I->getName(), Dest);
475 LocalMap.insert(std::make_pair(I, DBB));
477 // Loop over all of the instructions in the src basic block, copying them
478 // over. Note that this is broken in a strict sense because the cloned
479 // instructions will still be referencing values in the Src module, not
480 // the remapped values. In our case, however, we will not get caught and
481 // so we can delay patching the values up until later...
483 for (BasicBlock::const_iterator II = I->begin(), IE = I->end();
485 Instruction *DI = II->clone();
486 DI->setName(II->getName());
487 DBB->getInstList().push_back(DI);
488 LocalMap.insert(std::make_pair(II, DI));
492 // At this point, all of the instructions and values of the function are now
493 // copied over. The only problem is that they are still referencing values in
494 // the Source function as operands. Loop through all of the operands of the
495 // functions and patch them up to point to the local versions...
497 for (Function::iterator BB = Dest->begin(), BE = Dest->end(); BB != BE; ++BB)
498 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
499 for (Instruction::op_iterator OI = I->op_begin(), OE = I->op_end();
501 *OI = RemapOperand(*OI, LocalMap, &GlobalMap);
507 // LinkFunctionBodies - Link in the function bodies that are defined in the
508 // source module into the DestModule. This consists basically of copying the
509 // function over and fixing up references to values.
511 static bool LinkFunctionBodies(Module *Dest, const Module *Src,
512 std::map<const Value*, Value*> &ValueMap,
515 // Loop over all of the functions in the src module, mapping them over as we
518 for (Module::const_iterator SF = Src->begin(), E = Src->end(); SF != E; ++SF){
519 if (!SF->isExternal()) { // No body if function is external
520 Function *DF = cast<Function>(ValueMap[SF]); // Destination function
522 // DF not external SF external?
523 if (!DF->isExternal()) {
524 if (DF->hasLinkOnceLinkage()) continue; // No relinkage for link-once!
526 *Err = "Function '" + (SF->hasName() ? SF->getName() :std::string(""))
527 + "' body multiply defined!";
531 if (LinkFunctionBody(DF, SF, ValueMap, Err)) return true;
537 // LinkAppendingVars - If there were any appending global variables, link them
538 // together now. Return true on error.
540 static bool LinkAppendingVars(Module *M,
541 std::multimap<std::string, GlobalVariable *> &AppendingVars,
542 std::string *ErrorMsg) {
543 if (AppendingVars.empty()) return false; // Nothing to do.
545 // Loop over the multimap of appending vars, processing any variables with the
546 // same name, forming a new appending global variable with both of the
547 // initializers merged together, then rewrite references to the old variables
550 std::vector<Constant*> Inits;
551 while (AppendingVars.size() > 1) {
552 // Get the first two elements in the map...
553 std::multimap<std::string,
554 GlobalVariable*>::iterator Second = AppendingVars.begin(), First=Second++;
556 // If the first two elements are for different names, there is no pair...
557 // Otherwise there is a pair, so link them together...
558 if (First->first == Second->first) {
559 GlobalVariable *G1 = First->second, *G2 = Second->second;
560 const ArrayType *T1 = cast<ArrayType>(G1->getType()->getElementType());
561 const ArrayType *T2 = cast<ArrayType>(G2->getType()->getElementType());
563 // Check to see that they two arrays agree on type...
564 if (T1->getElementType() != T2->getElementType())
565 return Error(ErrorMsg,
566 "Appending variables with different element types need to be linked!");
567 if (G1->isConstant() != G2->isConstant())
568 return Error(ErrorMsg,
569 "Appending variables linked with different const'ness!");
571 unsigned NewSize = T1->getNumElements() + T2->getNumElements();
572 ArrayType *NewType = ArrayType::get(T1->getElementType(), NewSize);
574 // Create the new global variable...
576 new GlobalVariable(NewType, G1->isConstant(), G1->getLinkage(),
577 /*init*/0, First->first, M);
579 // Merge the initializer...
580 Inits.reserve(NewSize);
581 ConstantArray *I = cast<ConstantArray>(G1->getInitializer());
582 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i)
583 Inits.push_back(cast<Constant>(I->getValues()[i]));
584 I = cast<ConstantArray>(G2->getInitializer());
585 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i)
586 Inits.push_back(cast<Constant>(I->getValues()[i]));
587 NG->setInitializer(ConstantArray::get(NewType, Inits));
590 // Replace any uses of the two global variables with uses of the new
593 // FIXME: This should rewrite simple/straight-forward uses such as
594 // getelementptr instructions to not use the Cast!
595 ConstantPointerRef *NGCP = ConstantPointerRef::get(NG);
596 G1->replaceAllUsesWith(ConstantExpr::getCast(NGCP, G1->getType()));
597 G2->replaceAllUsesWith(ConstantExpr::getCast(NGCP, G2->getType()));
599 // Remove the two globals from the module now...
600 M->getGlobalList().erase(G1);
601 M->getGlobalList().erase(G2);
603 // Put the new global into the AppendingVars map so that we can handle
604 // linking of more than two vars...
607 AppendingVars.erase(First);
614 // LinkModules - This function links two modules together, with the resulting
615 // left module modified to be the composite of the two input modules. If an
616 // error occurs, true is returned and ErrorMsg (if not null) is set to indicate
617 // the problem. Upon failure, the Dest module could be in a modified state, and
618 // shouldn't be relied on to be consistent.
620 bool LinkModules(Module *Dest, const Module *Src, std::string *ErrorMsg) {
621 if (Dest->getEndianness() != Src->getEndianness())
622 std::cerr << "WARNING: Linking two modules of different endianness!\n";
623 if (Dest->getPointerSize() != Src->getPointerSize())
624 std::cerr << "WARNING: Linking two modules of different pointer size!\n";
626 // LinkTypes - Go through the symbol table of the Src module and see if any
627 // types are named in the src module that are not named in the Dst module.
628 // Make sure there are no type name conflicts.
630 if (LinkTypes(Dest, Src, ErrorMsg)) return true;
632 // ValueMap - Mapping of values from what they used to be in Src, to what they
635 std::map<const Value*, Value*> ValueMap;
637 // AppendingVars - Keep track of global variables in the destination module
638 // with appending linkage. After the module is linked together, they are
639 // appended and the module is rewritten.
641 std::multimap<std::string, GlobalVariable *> AppendingVars;
643 // Add all of the appending globals already in the Dest module to
645 for (Module::giterator I = Dest->gbegin(), E = Dest->gend(); I != E; ++I)
646 if (I->hasAppendingLinkage())
647 AppendingVars.insert(std::make_pair(I->getName(), I));
649 // Insert all of the globals in src into the Dest module... without linking
650 // initializers (which could refer to functions not yet mapped over).
652 if (LinkGlobals(Dest, Src, ValueMap, AppendingVars, ErrorMsg)) return true;
654 // Link the functions together between the two modules, without doing function
655 // bodies... this just adds external function prototypes to the Dest
656 // function... We do this so that when we begin processing function bodies,
657 // all of the global values that may be referenced are available in our
660 if (LinkFunctionProtos(Dest, Src, ValueMap, ErrorMsg)) return true;
662 // Update the initializers in the Dest module now that all globals that may
663 // be referenced are in Dest.
665 if (LinkGlobalInits(Dest, Src, ValueMap, ErrorMsg)) return true;
667 // Link in the function bodies that are defined in the source module into the
668 // DestModule. This consists basically of copying the function over and
669 // fixing up references to values.
671 if (LinkFunctionBodies(Dest, Src, ValueMap, ErrorMsg)) return true;
673 // If there were any appending global variables, link them together now.
675 if (LinkAppendingVars(Dest, AppendingVars, ErrorMsg)) return true;