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);
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 RecursiveResolveTypes(const PATypeHolder &DestTy,
63 const PATypeHolder &SrcTy,
64 SymbolTable *DestST, const std::string &Name){
65 const Type *SrcTyT = SrcTy.get();
66 const Type *DestTyT = DestTy.get();
67 if (DestTyT == SrcTyT) return false; // If already equal, noop
69 // If we found our opaque type, resolve it now!
70 if (isa<OpaqueType>(DestTyT) || isa<OpaqueType>(SrcTyT))
71 return ResolveTypes(DestTyT, SrcTyT, DestST, Name);
73 // Two types cannot be resolved together if they are of different primitive
74 // type. For example, we cannot resolve an int to a float.
75 if (DestTyT->getPrimitiveID() != SrcTyT->getPrimitiveID()) return true;
77 // Otherwise, resolve the used type used by this derived type...
78 switch (DestTyT->getPrimitiveID()) {
79 case Type::FunctionTyID: {
80 if (cast<FunctionType>(DestTyT)->isVarArg() !=
81 cast<FunctionType>(SrcTyT)->isVarArg())
83 for (unsigned i = 0, e = getFT(DestTy)->getNumContainedTypes(); i != e; ++i)
84 if (RecursiveResolveTypes(getFT(DestTy)->getContainedType(i),
85 getFT(SrcTy)->getContainedType(i), DestST,Name))
89 case Type::StructTyID: {
90 if (getST(DestTy)->getNumContainedTypes() !=
91 getST(SrcTy)->getNumContainedTypes()) return 1;
92 for (unsigned i = 0, e = getST(DestTy)->getNumContainedTypes(); i != e; ++i)
93 if (RecursiveResolveTypes(getST(DestTy)->getContainedType(i),
94 getST(SrcTy)->getContainedType(i), DestST,Name))
98 case Type::ArrayTyID: {
99 const ArrayType *DAT = cast<ArrayType>(DestTy.get());
100 const ArrayType *SAT = cast<ArrayType>(SrcTy.get());
101 if (DAT->getNumElements() != SAT->getNumElements()) return true;
102 return RecursiveResolveTypes(DAT->getElementType(), SAT->getElementType(),
105 case Type::PointerTyID:
106 return RecursiveResolveTypes(
107 cast<PointerType>(DestTy.get())->getElementType(),
108 cast<PointerType>(SrcTy.get())->getElementType(),
110 default: assert(0 && "Unexpected type!"); return true;
115 // LinkTypes - Go through the symbol table of the Src module and see if any
116 // types are named in the src module that are not named in the Dst module.
117 // Make sure there are no type name conflicts.
119 static bool LinkTypes(Module *Dest, const Module *Src, std::string *Err) {
120 SymbolTable *DestST = &Dest->getSymbolTable();
121 const SymbolTable *SrcST = &Src->getSymbolTable();
123 // Look for a type plane for Type's...
124 SymbolTable::const_iterator PI = SrcST->find(Type::TypeTy);
125 if (PI == SrcST->end()) return false; // No named types, do nothing.
127 // Some types cannot be resolved immediately becuse they depend on other types
128 // being resolved to each other first. This contains a list of types we are
129 // waiting to recheck.
130 std::vector<std::string> DelayedTypesToResolve;
132 const SymbolTable::VarMap &VM = PI->second;
133 for (SymbolTable::type_const_iterator I = VM.begin(), E = VM.end();
135 const std::string &Name = I->first;
136 Type *RHS = cast<Type>(I->second);
138 // Check to see if this type name is already in the dest module...
139 Type *Entry = cast_or_null<Type>(DestST->lookup(Type::TypeTy, Name));
141 if (ResolveTypes(Entry, RHS, DestST, Name)) {
142 // They look different, save the types 'till later to resolve.
143 DelayedTypesToResolve.push_back(Name);
147 // Iteratively resolve types while we can...
148 while (!DelayedTypesToResolve.empty()) {
149 // Loop over all of the types, attempting to resolve them if possible...
150 unsigned OldSize = DelayedTypesToResolve.size();
152 // Try direct resolution by name...
153 for (unsigned i = 0; i != DelayedTypesToResolve.size(); ++i) {
154 const std::string &Name = DelayedTypesToResolve[i];
155 Type *T1 = cast<Type>(VM.find(Name)->second);
156 Type *T2 = cast<Type>(DestST->lookup(Type::TypeTy, Name));
157 if (!ResolveTypes(T2, T1, DestST, Name)) {
158 // We are making progress!
159 DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i);
164 // Did we not eliminate any types?
165 if (DelayedTypesToResolve.size() == OldSize) {
166 // Attempt to resolve subelements of types. This allows us to merge these
167 // two types: { int* } and { opaque* }
168 for (unsigned i = 0, e = DelayedTypesToResolve.size(); i != e; ++i) {
169 const std::string &Name = DelayedTypesToResolve[i];
170 PATypeHolder T1(cast<Type>(VM.find(Name)->second));
171 PATypeHolder T2(cast<Type>(DestST->lookup(Type::TypeTy, Name)));
173 if (!RecursiveResolveTypes(T2, T1, DestST, Name)) {
174 // We are making progress!
175 DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i);
177 // Go back to the main loop, perhaps we can resolve directly by name
183 // If we STILL cannot resolve the types, then there is something wrong.
185 if (DelayedTypesToResolve.size() == OldSize) {
186 // Build up an error message of all of the mismatched types.
187 std::string ErrorMessage;
188 for (unsigned i = 0, e = DelayedTypesToResolve.size(); i != e; ++i) {
189 const std::string &Name = DelayedTypesToResolve[i];
190 const Type *T1 = cast<Type>(VM.find(Name)->second);
191 const Type *T2 = cast<Type>(DestST->lookup(Type::TypeTy, Name));
192 ErrorMessage += " Type named '" + Name +
193 "' conflicts.\n Src='" + T1->getDescription() +
194 "'.\n Dest='" + T2->getDescription() + "'\n";
196 return Error(Err, "Type conflict between types in modules:\n" +
206 static void PrintMap(const std::map<const Value*, Value*> &M) {
207 for (std::map<const Value*, Value*>::const_iterator I = M.begin(), E =M.end();
209 std::cerr << " Fr: " << (void*)I->first << " ";
211 std::cerr << " To: " << (void*)I->second << " ";
218 // RemapOperand - Use LocalMap and GlobalMap to convert references from one
219 // module to another. This is somewhat sophisticated in that it can
220 // automatically handle constant references correctly as well...
222 static Value *RemapOperand(const Value *In,
223 std::map<const Value*, Value*> &LocalMap,
224 std::map<const Value*, Value*> *GlobalMap) {
225 std::map<const Value*,Value*>::const_iterator I = LocalMap.find(In);
226 if (I != LocalMap.end()) return I->second;
229 I = GlobalMap->find(In);
230 if (I != GlobalMap->end()) return I->second;
233 // Check to see if it's a constant that we are interesting in transforming...
234 if (const Constant *CPV = dyn_cast<Constant>(In)) {
235 if (!isa<DerivedType>(CPV->getType()) && !isa<ConstantExpr>(CPV))
236 return const_cast<Constant*>(CPV); // Simple constants stay identical...
238 Constant *Result = 0;
240 if (const ConstantArray *CPA = dyn_cast<ConstantArray>(CPV)) {
241 const std::vector<Use> &Ops = CPA->getValues();
242 std::vector<Constant*> Operands(Ops.size());
243 for (unsigned i = 0, e = Ops.size(); i != e; ++i)
245 cast<Constant>(RemapOperand(Ops[i], LocalMap, GlobalMap));
246 Result = ConstantArray::get(cast<ArrayType>(CPA->getType()), Operands);
247 } else if (const ConstantStruct *CPS = dyn_cast<ConstantStruct>(CPV)) {
248 const std::vector<Use> &Ops = CPS->getValues();
249 std::vector<Constant*> Operands(Ops.size());
250 for (unsigned i = 0; i < Ops.size(); ++i)
252 cast<Constant>(RemapOperand(Ops[i], LocalMap, GlobalMap));
253 Result = ConstantStruct::get(cast<StructType>(CPS->getType()), Operands);
254 } else if (isa<ConstantPointerNull>(CPV)) {
255 Result = const_cast<Constant*>(CPV);
256 } else if (const ConstantPointerRef *CPR =
257 dyn_cast<ConstantPointerRef>(CPV)) {
258 Value *V = RemapOperand(CPR->getValue(), LocalMap, GlobalMap);
259 Result = ConstantPointerRef::get(cast<GlobalValue>(V));
260 } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CPV)) {
261 if (CE->getOpcode() == Instruction::GetElementPtr) {
262 Value *Ptr = RemapOperand(CE->getOperand(0), LocalMap, GlobalMap);
263 std::vector<Constant*> Indices;
264 Indices.reserve(CE->getNumOperands()-1);
265 for (unsigned i = 1, e = CE->getNumOperands(); i != e; ++i)
266 Indices.push_back(cast<Constant>(RemapOperand(CE->getOperand(i),
267 LocalMap, GlobalMap)));
269 Result = ConstantExpr::getGetElementPtr(cast<Constant>(Ptr), Indices);
270 } else if (CE->getNumOperands() == 1) {
272 assert(CE->getOpcode() == Instruction::Cast);
273 Value *V = RemapOperand(CE->getOperand(0), LocalMap, GlobalMap);
274 Result = ConstantExpr::getCast(cast<Constant>(V), CE->getType());
275 } else if (CE->getNumOperands() == 2) {
276 // Binary operator...
277 Value *V1 = RemapOperand(CE->getOperand(0), LocalMap, GlobalMap);
278 Value *V2 = RemapOperand(CE->getOperand(1), LocalMap, GlobalMap);
280 Result = ConstantExpr::get(CE->getOpcode(), cast<Constant>(V1),
283 assert(0 && "Unknown constant expr type!");
287 assert(0 && "Unknown type of derived type constant value!");
290 // Cache the mapping in our local map structure...
292 GlobalMap->insert(std::make_pair(In, Result));
294 LocalMap.insert(std::make_pair(In, Result));
298 std::cerr << "XXX LocalMap: \n";
302 std::cerr << "XXX GlobalMap: \n";
303 PrintMap(*GlobalMap);
306 std::cerr << "Couldn't remap value: " << (void*)In << " " << *In << "\n";
307 assert(0 && "Couldn't remap value!");
312 // LinkGlobals - Loop through the global variables in the src module and merge
313 // them into the dest module.
315 static bool LinkGlobals(Module *Dest, const Module *Src,
316 std::map<const Value*, Value*> &ValueMap,
317 std::multimap<std::string, GlobalVariable *> &AppendingVars,
319 // We will need a module level symbol table if the src module has a module
320 // level symbol table...
321 SymbolTable *ST = (SymbolTable*)&Dest->getSymbolTable();
323 // Loop over all of the globals in the src module, mapping them over as we go
325 for (Module::const_giterator I = Src->gbegin(), E = Src->gend(); I != E; ++I){
326 const GlobalVariable *SGV = I;
327 GlobalVariable *DGV = 0;
328 if (SGV->hasName()) {
329 // A same named thing is a global variable, because the only two things
330 // that may be in a module level symbol table are Global Vars and
331 // Functions, and they both have distinct, nonoverlapping, possible types.
333 DGV = cast_or_null<GlobalVariable>(ST->lookup(SGV->getType(),
337 assert(SGV->hasInitializer() || SGV->hasExternalLinkage() &&
338 "Global must either be external or have an initializer!");
340 bool SGExtern = SGV->isExternal();
341 bool DGExtern = DGV ? DGV->isExternal() : false;
343 if (!DGV || DGV->hasInternalLinkage() || SGV->hasInternalLinkage()) {
344 // No linking to be performed, simply create an identical version of the
345 // symbol over in the dest module... the initializer will be filled in
346 // later by LinkGlobalInits...
348 GlobalVariable *NewDGV =
349 new GlobalVariable(SGV->getType()->getElementType(),
350 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
351 SGV->getName(), Dest);
353 // If the LLVM runtime renamed the global, but it is an externally visible
354 // symbol, DGV must be an existing global with internal linkage. Rename
356 if (NewDGV->getName() != SGV->getName() && !NewDGV->hasInternalLinkage()){
357 assert(DGV && DGV->getName() == SGV->getName() &&
358 DGV->hasInternalLinkage());
360 NewDGV->setName(SGV->getName()); // Force the name back
361 DGV->setName(SGV->getName()); // This will cause a renaming
362 assert(NewDGV->getName() == SGV->getName() &&
363 DGV->getName() != SGV->getName());
366 // Make sure to remember this mapping...
367 ValueMap.insert(std::make_pair(SGV, NewDGV));
368 if (SGV->hasAppendingLinkage())
369 // Keep track that this is an appending variable...
370 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV));
372 } else if (SGV->isExternal()) {
373 // If SGV is external or if both SGV & DGV are external.. Just link the
374 // external globals, we aren't adding anything.
375 ValueMap.insert(std::make_pair(SGV, DGV));
377 } else if (DGV->isExternal()) { // If DGV is external but SGV is not...
378 ValueMap.insert(std::make_pair(SGV, DGV));
379 DGV->setLinkage(SGV->getLinkage()); // Inherit linkage!
380 } else if (SGV->getLinkage() != DGV->getLinkage()) {
381 return Error(Err, "Global variables named '" + SGV->getName() +
382 "' have different linkage specifiers!");
383 } else if (SGV->hasExternalLinkage()) {
384 // Allow linking two exactly identical external global variables...
385 if (SGV->isConstant() != DGV->isConstant() ||
386 SGV->getInitializer() != DGV->getInitializer())
387 return Error(Err, "Global Variable Collision on '" +
388 SGV->getType()->getDescription() + " %" + SGV->getName() +
389 "' - Global variables differ in const'ness");
390 ValueMap.insert(std::make_pair(SGV, DGV));
391 } else if (SGV->hasLinkOnceLinkage()) {
392 // If the global variable has a name, and that name is already in use in
393 // the Dest module, make sure that the name is a compatible global
396 // Check to see if the two GV's have the same Const'ness...
397 if (SGV->isConstant() != DGV->isConstant())
398 return Error(Err, "Global Variable Collision on '" +
399 SGV->getType()->getDescription() + " %" + SGV->getName() +
400 "' - Global variables differ in const'ness");
402 // Okay, everything is cool, remember the mapping...
403 ValueMap.insert(std::make_pair(SGV, DGV));
404 } else if (SGV->hasAppendingLinkage()) {
405 // No linking is performed yet. Just insert a new copy of the global, and
406 // keep track of the fact that it is an appending variable in the
407 // AppendingVars map. The name is cleared out so that no linkage is
409 GlobalVariable *NewDGV =
410 new GlobalVariable(SGV->getType()->getElementType(),
411 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
414 // Make sure to remember this mapping...
415 ValueMap.insert(std::make_pair(SGV, NewDGV));
417 // Keep track that this is an appending variable...
418 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV));
420 assert(0 && "Unknown linkage!");
427 // LinkGlobalInits - Update the initializers in the Dest module now that all
428 // globals that may be referenced are in Dest.
430 static bool LinkGlobalInits(Module *Dest, const Module *Src,
431 std::map<const Value*, Value*> &ValueMap,
434 // Loop over all of the globals in the src module, mapping them over as we go
436 for (Module::const_giterator I = Src->gbegin(), E = Src->gend(); I != E; ++I){
437 const GlobalVariable *SGV = I;
439 if (SGV->hasInitializer()) { // Only process initialized GV's
440 // Figure out what the initializer looks like in the dest module...
442 cast<Constant>(RemapOperand(SGV->getInitializer(), ValueMap, 0));
444 GlobalVariable *DGV = cast<GlobalVariable>(ValueMap[SGV]);
445 if (DGV->hasInitializer()) {
446 assert(SGV->getLinkage() == DGV->getLinkage());
447 if (SGV->hasExternalLinkage()) {
448 if (DGV->getInitializer() != SInit)
449 return Error(Err, "Global Variable Collision on '" +
450 SGV->getType()->getDescription() +"':%"+SGV->getName()+
451 " - Global variables have different initializers");
452 } else if (DGV->hasLinkOnceLinkage()) {
453 // Nothing is required, mapped values will take the new global
455 } else if (DGV->hasAppendingLinkage()) {
456 assert(0 && "Appending linkage unimplemented!");
458 assert(0 && "Unknown linkage!");
461 // Copy the initializer over now...
462 DGV->setInitializer(SInit);
469 // LinkFunctionProtos - Link the functions together between the two modules,
470 // without doing function bodies... this just adds external function prototypes
471 // to the Dest function...
473 static bool LinkFunctionProtos(Module *Dest, const Module *Src,
474 std::map<const Value*, Value*> &ValueMap,
476 SymbolTable *ST = (SymbolTable*)&Dest->getSymbolTable();
478 // Loop over all of the functions in the src module, mapping them over as we
481 for (Module::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) {
482 const Function *SF = I; // SrcFunction
485 // The same named thing is a Function, because the only two things
486 // that may be in a module level symbol table are Global Vars and
487 // Functions, and they both have distinct, nonoverlapping, possible types.
489 DF = cast_or_null<Function>(ST->lookup(SF->getType(), SF->getName()));
491 if (!DF || SF->hasInternalLinkage() || DF->hasInternalLinkage()) {
492 // Function does not already exist, simply insert an function signature
493 // identical to SF into the dest module...
494 Function *NewDF = new Function(SF->getFunctionType(), SF->getLinkage(),
495 SF->getName(), Dest);
497 // If the LLVM runtime renamed the function, but it is an externally
498 // visible symbol, DF must be an existing function with internal linkage.
500 if (NewDF->getName() != SF->getName() && !NewDF->hasInternalLinkage()) {
501 assert(DF && DF->getName() == SF->getName() &&DF->hasInternalLinkage());
503 NewDF->setName(SF->getName()); // Force the name back
504 DF->setName(SF->getName()); // This will cause a renaming
505 assert(NewDF->getName() == SF->getName() &&
506 DF->getName() != SF->getName());
509 // ... and remember this mapping...
510 ValueMap.insert(std::make_pair(SF, NewDF));
511 } else if (SF->isExternal()) {
512 // If SF is external or if both SF & DF are external.. Just link the
513 // external functions, we aren't adding anything.
514 ValueMap.insert(std::make_pair(SF, DF));
515 } else if (DF->isExternal()) { // If DF is external but SF is not...
516 // Link the external functions, update linkage qualifiers
517 ValueMap.insert(std::make_pair(SF, DF));
518 DF->setLinkage(SF->getLinkage());
520 } else if (SF->getLinkage() != DF->getLinkage()) {
521 return Error(Err, "Functions named '" + SF->getName() +
522 "' have different linkage specifiers!");
523 } else if (SF->hasExternalLinkage()) {
524 // The function is defined in both modules!!
525 return Error(Err, "Function '" +
526 SF->getFunctionType()->getDescription() + "':\"" +
527 SF->getName() + "\" - Function is already defined!");
528 } else if (SF->hasLinkOnceLinkage()) {
529 // Completely ignore the source function.
530 ValueMap.insert(std::make_pair(SF, DF));
532 assert(0 && "Unknown linkage configuration found!");
538 // LinkFunctionBody - Copy the source function over into the dest function and
539 // fix up references to values. At this point we know that Dest is an external
540 // function, and that Src is not.
542 static bool LinkFunctionBody(Function *Dest, const Function *Src,
543 std::map<const Value*, Value*> &GlobalMap,
545 assert(Src && Dest && Dest->isExternal() && !Src->isExternal());
546 std::map<const Value*, Value*> LocalMap; // Map for function local values
548 // Go through and convert function arguments over...
549 Function::aiterator DI = Dest->abegin();
550 for (Function::const_aiterator I = Src->abegin(), E = Src->aend();
552 DI->setName(I->getName()); // Copy the name information over...
554 // Add a mapping to our local map
555 LocalMap.insert(std::make_pair(I, DI));
558 // Loop over all of the basic blocks, copying the instructions over...
560 for (Function::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) {
561 // Create new basic block and add to mapping and the Dest function...
562 BasicBlock *DBB = new BasicBlock(I->getName(), Dest);
563 LocalMap.insert(std::make_pair(I, DBB));
565 // Loop over all of the instructions in the src basic block, copying them
566 // over. Note that this is broken in a strict sense because the cloned
567 // instructions will still be referencing values in the Src module, not
568 // the remapped values. In our case, however, we will not get caught and
569 // so we can delay patching the values up until later...
571 for (BasicBlock::const_iterator II = I->begin(), IE = I->end();
573 Instruction *DI = II->clone();
574 DI->setName(II->getName());
575 DBB->getInstList().push_back(DI);
576 LocalMap.insert(std::make_pair(II, DI));
580 // At this point, all of the instructions and values of the function are now
581 // copied over. The only problem is that they are still referencing values in
582 // the Source function as operands. Loop through all of the operands of the
583 // functions and patch them up to point to the local versions...
585 for (Function::iterator BB = Dest->begin(), BE = Dest->end(); BB != BE; ++BB)
586 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
587 for (Instruction::op_iterator OI = I->op_begin(), OE = I->op_end();
589 *OI = RemapOperand(*OI, LocalMap, &GlobalMap);
595 // LinkFunctionBodies - Link in the function bodies that are defined in the
596 // source module into the DestModule. This consists basically of copying the
597 // function over and fixing up references to values.
599 static bool LinkFunctionBodies(Module *Dest, const Module *Src,
600 std::map<const Value*, Value*> &ValueMap,
603 // Loop over all of the functions in the src module, mapping them over as we
606 for (Module::const_iterator SF = Src->begin(), E = Src->end(); SF != E; ++SF){
607 if (!SF->isExternal()) { // No body if function is external
608 Function *DF = cast<Function>(ValueMap[SF]); // Destination function
610 // DF not external SF external?
611 if (!DF->isExternal()) {
612 if (DF->hasLinkOnceLinkage()) continue; // No relinkage for link-once!
614 *Err = "Function '" + (SF->hasName() ? SF->getName() :std::string(""))
615 + "' body multiply defined!";
619 if (LinkFunctionBody(DF, SF, ValueMap, Err)) return true;
625 // LinkAppendingVars - If there were any appending global variables, link them
626 // together now. Return true on error.
628 static bool LinkAppendingVars(Module *M,
629 std::multimap<std::string, GlobalVariable *> &AppendingVars,
630 std::string *ErrorMsg) {
631 if (AppendingVars.empty()) return false; // Nothing to do.
633 // Loop over the multimap of appending vars, processing any variables with the
634 // same name, forming a new appending global variable with both of the
635 // initializers merged together, then rewrite references to the old variables
638 std::vector<Constant*> Inits;
639 while (AppendingVars.size() > 1) {
640 // Get the first two elements in the map...
641 std::multimap<std::string,
642 GlobalVariable*>::iterator Second = AppendingVars.begin(), First=Second++;
644 // If the first two elements are for different names, there is no pair...
645 // Otherwise there is a pair, so link them together...
646 if (First->first == Second->first) {
647 GlobalVariable *G1 = First->second, *G2 = Second->second;
648 const ArrayType *T1 = cast<ArrayType>(G1->getType()->getElementType());
649 const ArrayType *T2 = cast<ArrayType>(G2->getType()->getElementType());
651 // Check to see that they two arrays agree on type...
652 if (T1->getElementType() != T2->getElementType())
653 return Error(ErrorMsg,
654 "Appending variables with different element types need to be linked!");
655 if (G1->isConstant() != G2->isConstant())
656 return Error(ErrorMsg,
657 "Appending variables linked with different const'ness!");
659 unsigned NewSize = T1->getNumElements() + T2->getNumElements();
660 ArrayType *NewType = ArrayType::get(T1->getElementType(), NewSize);
662 // Create the new global variable...
664 new GlobalVariable(NewType, G1->isConstant(), G1->getLinkage(),
665 /*init*/0, First->first, M);
667 // Merge the initializer...
668 Inits.reserve(NewSize);
669 ConstantArray *I = cast<ConstantArray>(G1->getInitializer());
670 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i)
671 Inits.push_back(cast<Constant>(I->getValues()[i]));
672 I = cast<ConstantArray>(G2->getInitializer());
673 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i)
674 Inits.push_back(cast<Constant>(I->getValues()[i]));
675 NG->setInitializer(ConstantArray::get(NewType, Inits));
678 // Replace any uses of the two global variables with uses of the new
681 // FIXME: This should rewrite simple/straight-forward uses such as
682 // getelementptr instructions to not use the Cast!
683 ConstantPointerRef *NGCP = ConstantPointerRef::get(NG);
684 G1->replaceAllUsesWith(ConstantExpr::getCast(NGCP, G1->getType()));
685 G2->replaceAllUsesWith(ConstantExpr::getCast(NGCP, G2->getType()));
687 // Remove the two globals from the module now...
688 M->getGlobalList().erase(G1);
689 M->getGlobalList().erase(G2);
691 // Put the new global into the AppendingVars map so that we can handle
692 // linking of more than two vars...
695 AppendingVars.erase(First);
702 // LinkModules - This function links two modules together, with the resulting
703 // left module modified to be the composite of the two input modules. If an
704 // error occurs, true is returned and ErrorMsg (if not null) is set to indicate
705 // the problem. Upon failure, the Dest module could be in a modified state, and
706 // shouldn't be relied on to be consistent.
708 bool LinkModules(Module *Dest, const Module *Src, std::string *ErrorMsg) {
709 if (Dest->getEndianness() != Src->getEndianness())
710 std::cerr << "WARNING: Linking two modules of different endianness!\n";
711 if (Dest->getPointerSize() != Src->getPointerSize())
712 std::cerr << "WARNING: Linking two modules of different pointer size!\n";
714 // LinkTypes - Go through the symbol table of the Src module and see if any
715 // types are named in the src module that are not named in the Dst module.
716 // Make sure there are no type name conflicts.
718 if (LinkTypes(Dest, Src, ErrorMsg)) return true;
720 // ValueMap - Mapping of values from what they used to be in Src, to what they
723 std::map<const Value*, Value*> ValueMap;
725 // AppendingVars - Keep track of global variables in the destination module
726 // with appending linkage. After the module is linked together, they are
727 // appended and the module is rewritten.
729 std::multimap<std::string, GlobalVariable *> AppendingVars;
731 // Add all of the appending globals already in the Dest module to
733 for (Module::giterator I = Dest->gbegin(), E = Dest->gend(); I != E; ++I)
734 if (I->hasAppendingLinkage())
735 AppendingVars.insert(std::make_pair(I->getName(), I));
737 // Insert all of the globals in src into the Dest module... without linking
738 // initializers (which could refer to functions not yet mapped over).
740 if (LinkGlobals(Dest, Src, ValueMap, AppendingVars, ErrorMsg)) return true;
742 // Link the functions together between the two modules, without doing function
743 // bodies... this just adds external function prototypes to the Dest
744 // function... We do this so that when we begin processing function bodies,
745 // all of the global values that may be referenced are available in our
748 if (LinkFunctionProtos(Dest, Src, ValueMap, ErrorMsg)) return true;
750 // Update the initializers in the Dest module now that all globals that may
751 // be referenced are in Dest.
753 if (LinkGlobalInits(Dest, Src, ValueMap, ErrorMsg)) return true;
755 // Link in the function bodies that are defined in the source module into the
756 // DestModule. This consists basically of copying the function over and
757 // fixing up references to values.
759 if (LinkFunctionBodies(Dest, Src, ValueMap, ErrorMsg)) return true;
761 // If there were any appending global variables, link them together now.
763 if (LinkAppendingVars(Dest, AppendingVars, ErrorMsg)) return true;