1 //===- lib/Linker/LinkModules.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/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"
26 #include "llvm/System/Path.h"
31 // Error - Simple wrapper function to conditionally assign to E and return true.
32 // This just makes error return conditions a little bit simpler...
33 static inline bool Error(std::string *E, const std::string &Message) {
38 // ToStr - Simple wrapper function to convert a type to a string.
39 static std::string ToStr(const Type *Ty, const Module *M) {
40 std::ostringstream OS;
41 WriteTypeSymbolic(OS, Ty, M);
46 // Function: ResolveTypes()
49 // Attempt to link the two specified types together.
52 // DestTy - The type to which we wish to resolve.
53 // SrcTy - The original type which we want to resolve.
54 // Name - The name of the type.
57 // DestST - The symbol table in which the new type should be placed.
60 // true - There is an error and the types cannot yet be linked.
63 static bool ResolveTypes(const Type *DestTy, const Type *SrcTy,
64 SymbolTable *DestST, const std::string &Name) {
65 if (DestTy == SrcTy) return false; // If already equal, noop
67 // Does the type already exist in the module?
68 if (DestTy && !isa<OpaqueType>(DestTy)) { // Yup, the type already exists...
69 if (const OpaqueType *OT = dyn_cast<OpaqueType>(SrcTy)) {
70 const_cast<OpaqueType*>(OT)->refineAbstractTypeTo(DestTy);
72 return true; // Cannot link types... neither is opaque and not-equal
74 } else { // Type not in dest module. Add it now.
75 if (DestTy) // Type _is_ in module, just opaque...
76 const_cast<OpaqueType*>(cast<OpaqueType>(DestTy))
77 ->refineAbstractTypeTo(SrcTy);
78 else if (!Name.empty())
79 DestST->insert(Name, const_cast<Type*>(SrcTy));
84 static const FunctionType *getFT(const PATypeHolder &TH) {
85 return cast<FunctionType>(TH.get());
87 static const StructType *getST(const PATypeHolder &TH) {
88 return cast<StructType>(TH.get());
91 // RecursiveResolveTypes - This is just like ResolveTypes, except that it
92 // recurses down into derived types, merging the used types if the parent types
94 static bool RecursiveResolveTypesI(const PATypeHolder &DestTy,
95 const PATypeHolder &SrcTy,
96 SymbolTable *DestST, const std::string &Name,
97 std::vector<std::pair<PATypeHolder, PATypeHolder> > &Pointers) {
98 const Type *SrcTyT = SrcTy.get();
99 const Type *DestTyT = DestTy.get();
100 if (DestTyT == SrcTyT) return false; // If already equal, noop
102 // If we found our opaque type, resolve it now!
103 if (isa<OpaqueType>(DestTyT) || isa<OpaqueType>(SrcTyT))
104 return ResolveTypes(DestTyT, SrcTyT, DestST, Name);
106 // Two types cannot be resolved together if they are of different primitive
107 // type. For example, we cannot resolve an int to a float.
108 if (DestTyT->getTypeID() != SrcTyT->getTypeID()) return true;
110 // Otherwise, resolve the used type used by this derived type...
111 switch (DestTyT->getTypeID()) {
112 case Type::FunctionTyID: {
113 if (cast<FunctionType>(DestTyT)->isVarArg() !=
114 cast<FunctionType>(SrcTyT)->isVarArg() ||
115 cast<FunctionType>(DestTyT)->getNumContainedTypes() !=
116 cast<FunctionType>(SrcTyT)->getNumContainedTypes())
118 for (unsigned i = 0, e = getFT(DestTy)->getNumContainedTypes(); i != e; ++i)
119 if (RecursiveResolveTypesI(getFT(DestTy)->getContainedType(i),
120 getFT(SrcTy)->getContainedType(i), DestST, "",
125 case Type::StructTyID: {
126 if (getST(DestTy)->getNumContainedTypes() !=
127 getST(SrcTy)->getNumContainedTypes()) return 1;
128 for (unsigned i = 0, e = getST(DestTy)->getNumContainedTypes(); i != e; ++i)
129 if (RecursiveResolveTypesI(getST(DestTy)->getContainedType(i),
130 getST(SrcTy)->getContainedType(i), DestST, "",
135 case Type::ArrayTyID: {
136 const ArrayType *DAT = cast<ArrayType>(DestTy.get());
137 const ArrayType *SAT = cast<ArrayType>(SrcTy.get());
138 if (DAT->getNumElements() != SAT->getNumElements()) return true;
139 return RecursiveResolveTypesI(DAT->getElementType(), SAT->getElementType(),
140 DestST, "", Pointers);
142 case Type::PointerTyID: {
143 // If this is a pointer type, check to see if we have already seen it. If
144 // so, we are in a recursive branch. Cut off the search now. We cannot use
145 // an associative container for this search, because the type pointers (keys
146 // in the container) change whenever types get resolved...
147 for (unsigned i = 0, e = Pointers.size(); i != e; ++i)
148 if (Pointers[i].first == DestTy)
149 return Pointers[i].second != SrcTy;
151 // Otherwise, add the current pointers to the vector to stop recursion on
153 Pointers.push_back(std::make_pair(DestTyT, SrcTyT));
155 RecursiveResolveTypesI(cast<PointerType>(DestTy.get())->getElementType(),
156 cast<PointerType>(SrcTy.get())->getElementType(),
157 DestST, "", Pointers);
161 default: assert(0 && "Unexpected type!"); return true;
165 static bool RecursiveResolveTypes(const PATypeHolder &DestTy,
166 const PATypeHolder &SrcTy,
167 SymbolTable *DestST, const std::string &Name){
168 std::vector<std::pair<PATypeHolder, PATypeHolder> > PointerTypes;
169 return RecursiveResolveTypesI(DestTy, SrcTy, DestST, Name, PointerTypes);
173 // LinkTypes - Go through the symbol table of the Src module and see if any
174 // types are named in the src module that are not named in the Dst module.
175 // Make sure there are no type name conflicts.
176 static bool LinkTypes(Module *Dest, const Module *Src, std::string *Err) {
177 SymbolTable *DestST = &Dest->getSymbolTable();
178 const SymbolTable *SrcST = &Src->getSymbolTable();
180 // Look for a type plane for Type's...
181 SymbolTable::type_const_iterator TI = SrcST->type_begin();
182 SymbolTable::type_const_iterator TE = SrcST->type_end();
183 if (TI == TE) return false; // No named types, do nothing.
185 // Some types cannot be resolved immediately because they depend on other
186 // types being resolved to each other first. This contains a list of types we
187 // are waiting to recheck.
188 std::vector<std::string> DelayedTypesToResolve;
190 for ( ; TI != TE; ++TI ) {
191 const std::string &Name = TI->first;
192 const Type *RHS = TI->second;
194 // Check to see if this type name is already in the dest module...
195 Type *Entry = DestST->lookupType(Name);
197 if (ResolveTypes(Entry, RHS, DestST, Name)) {
198 // They look different, save the types 'till later to resolve.
199 DelayedTypesToResolve.push_back(Name);
203 // Iteratively resolve types while we can...
204 while (!DelayedTypesToResolve.empty()) {
205 // Loop over all of the types, attempting to resolve them if possible...
206 unsigned OldSize = DelayedTypesToResolve.size();
208 // Try direct resolution by name...
209 for (unsigned i = 0; i != DelayedTypesToResolve.size(); ++i) {
210 const std::string &Name = DelayedTypesToResolve[i];
211 Type *T1 = SrcST->lookupType(Name);
212 Type *T2 = DestST->lookupType(Name);
213 if (!ResolveTypes(T2, T1, DestST, Name)) {
214 // We are making progress!
215 DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i);
220 // Did we not eliminate any types?
221 if (DelayedTypesToResolve.size() == OldSize) {
222 // Attempt to resolve subelements of types. This allows us to merge these
223 // two types: { int* } and { opaque* }
224 for (unsigned i = 0, e = DelayedTypesToResolve.size(); i != e; ++i) {
225 const std::string &Name = DelayedTypesToResolve[i];
226 PATypeHolder T1(SrcST->lookupType(Name));
227 PATypeHolder T2(DestST->lookupType(Name));
229 if (!RecursiveResolveTypes(T2, T1, DestST, Name)) {
230 // We are making progress!
231 DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i);
233 // Go back to the main loop, perhaps we can resolve directly by name
239 // If we STILL cannot resolve the types, then there is something wrong.
240 // Report the warning and delete one of the names.
241 if (DelayedTypesToResolve.size() == OldSize) {
242 const std::string &Name = DelayedTypesToResolve.back();
244 const Type *T1 = SrcST->lookupType(Name);
245 const Type *T2 = DestST->lookupType(Name);
246 std::cerr << "WARNING: Type conflict between types named '" << Name
248 WriteTypeSymbolic(std::cerr, T1, Src);
249 std::cerr << "'.\n Dest='";
250 WriteTypeSymbolic(std::cerr, T2, Dest);
253 // Remove the symbol name from the destination.
254 DelayedTypesToResolve.pop_back();
263 static void PrintMap(const std::map<const Value*, Value*> &M) {
264 for (std::map<const Value*, Value*>::const_iterator I = M.begin(), E =M.end();
266 std::cerr << " Fr: " << (void*)I->first << " ";
268 std::cerr << " To: " << (void*)I->second << " ";
275 // RemapOperand - Use ValueMap to convert references from one module to another.
276 // This is somewhat sophisticated in that it can automatically handle constant
277 // references correctly as well...
278 static Value *RemapOperand(const Value *In,
279 std::map<const Value*, Value*> &ValueMap) {
280 std::map<const Value*,Value*>::const_iterator I = ValueMap.find(In);
281 if (I != ValueMap.end()) return I->second;
283 // Check to see if it's a constant that we are interesting in transforming.
284 if (const Constant *CPV = dyn_cast<Constant>(In)) {
285 if ((!isa<DerivedType>(CPV->getType()) && !isa<ConstantExpr>(CPV)) ||
286 isa<ConstantAggregateZero>(CPV))
287 return const_cast<Constant*>(CPV); // Simple constants stay identical.
289 Constant *Result = 0;
291 if (const ConstantArray *CPA = dyn_cast<ConstantArray>(CPV)) {
292 std::vector<Constant*> Operands(CPA->getNumOperands());
293 for (unsigned i = 0, e = CPA->getNumOperands(); i != e; ++i)
294 Operands[i] =cast<Constant>(RemapOperand(CPA->getOperand(i), ValueMap));
295 Result = ConstantArray::get(cast<ArrayType>(CPA->getType()), Operands);
296 } else if (const ConstantStruct *CPS = dyn_cast<ConstantStruct>(CPV)) {
297 std::vector<Constant*> Operands(CPS->getNumOperands());
298 for (unsigned i = 0, e = CPS->getNumOperands(); i != e; ++i)
299 Operands[i] =cast<Constant>(RemapOperand(CPS->getOperand(i), ValueMap));
300 Result = ConstantStruct::get(cast<StructType>(CPS->getType()), Operands);
301 } else if (isa<ConstantPointerNull>(CPV) || isa<UndefValue>(CPV)) {
302 Result = const_cast<Constant*>(CPV);
303 } else if (isa<GlobalValue>(CPV)) {
304 Result = cast<Constant>(RemapOperand(CPV, ValueMap));
305 } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CPV)) {
306 if (CE->getOpcode() == Instruction::GetElementPtr) {
307 Value *Ptr = RemapOperand(CE->getOperand(0), ValueMap);
308 std::vector<Constant*> Indices;
309 Indices.reserve(CE->getNumOperands()-1);
310 for (unsigned i = 1, e = CE->getNumOperands(); i != e; ++i)
311 Indices.push_back(cast<Constant>(RemapOperand(CE->getOperand(i),
314 Result = ConstantExpr::getGetElementPtr(cast<Constant>(Ptr), Indices);
315 } else if (CE->getNumOperands() == 1) {
317 assert(CE->getOpcode() == Instruction::Cast);
318 Value *V = RemapOperand(CE->getOperand(0), ValueMap);
319 Result = ConstantExpr::getCast(cast<Constant>(V), CE->getType());
320 } else if (CE->getNumOperands() == 3) {
321 // Select instruction
322 assert(CE->getOpcode() == Instruction::Select);
323 Value *V1 = RemapOperand(CE->getOperand(0), ValueMap);
324 Value *V2 = RemapOperand(CE->getOperand(1), ValueMap);
325 Value *V3 = RemapOperand(CE->getOperand(2), ValueMap);
326 Result = ConstantExpr::getSelect(cast<Constant>(V1), cast<Constant>(V2),
328 } else if (CE->getNumOperands() == 2) {
329 // Binary operator...
330 Value *V1 = RemapOperand(CE->getOperand(0), ValueMap);
331 Value *V2 = RemapOperand(CE->getOperand(1), ValueMap);
333 Result = ConstantExpr::get(CE->getOpcode(), cast<Constant>(V1),
336 assert(0 && "Unknown constant expr type!");
340 assert(0 && "Unknown type of derived type constant value!");
343 // Cache the mapping in our local map structure...
344 ValueMap.insert(std::make_pair(In, Result));
348 std::cerr << "LinkModules ValueMap: \n";
351 std::cerr << "Couldn't remap value: " << (void*)In << " " << *In << "\n";
352 assert(0 && "Couldn't remap value!");
356 /// ForceRenaming - The LLVM SymbolTable class autorenames globals that conflict
357 /// in the symbol table. This is good for all clients except for us. Go
358 /// through the trouble to force this back.
359 static void ForceRenaming(GlobalValue *GV, const std::string &Name) {
360 assert(GV->getName() != Name && "Can't force rename to self");
361 SymbolTable &ST = GV->getParent()->getSymbolTable();
363 // If there is a conflict, rename the conflict.
364 Value *ConflictVal = ST.lookup(GV->getType(), Name);
365 assert(ConflictVal&&"Why do we have to force rename if there is no conflic?");
366 GlobalValue *ConflictGV = cast<GlobalValue>(ConflictVal);
367 assert(ConflictGV->hasInternalLinkage() &&
368 "Not conflicting with a static global, should link instead!");
370 ConflictGV->setName(""); // Eliminate the conflict
371 GV->setName(Name); // Force the name back
372 ConflictGV->setName(Name); // This will cause ConflictGV to get renamed
373 assert(GV->getName() == Name && ConflictGV->getName() != Name &&
374 "ForceRenaming didn't work");
377 /// GetLinkageResult - This analyzes the two global values and determines what
378 /// the result will look like in the destination module. In particular, it
379 /// computes the resultant linkage type, computes whether the global in the
380 /// source should be copied over to the destination (replacing the existing
381 /// one), and computes whether this linkage is an error or not.
382 static bool GetLinkageResult(GlobalValue *Dest, GlobalValue *Src,
383 GlobalValue::LinkageTypes <, bool &LinkFromSrc,
385 assert((!Dest || !Src->hasInternalLinkage()) &&
386 "If Src has internal linkage, Dest shouldn't be set!");
388 // Linking something to nothing.
390 LT = Src->getLinkage();
391 } else if (Src->isExternal()) {
392 // If Src is external or if both Src & Drc are external.. Just link the
393 // external globals, we aren't adding anything.
395 LT = Dest->getLinkage();
396 } else if (Dest->isExternal()) {
397 // If Dest is external but Src is not:
399 LT = Src->getLinkage();
400 } else if (Src->hasAppendingLinkage() || Dest->hasAppendingLinkage()) {
401 if (Src->getLinkage() != Dest->getLinkage())
402 return Error(Err, "Linking globals named '" + Src->getName() +
403 "': can only link appending global with another appending global!");
404 LinkFromSrc = true; // Special cased.
405 LT = Src->getLinkage();
406 } else if (Src->hasWeakLinkage() || Src->hasLinkOnceLinkage()) {
407 // At this point we know that Dest has LinkOnce, External or Weak linkage.
408 if (Dest->hasLinkOnceLinkage() && Src->hasWeakLinkage()) {
410 LT = Src->getLinkage();
413 LT = Dest->getLinkage();
415 } else if (Dest->hasWeakLinkage() || Dest->hasLinkOnceLinkage()) {
416 // At this point we know that Src has External linkage.
418 LT = GlobalValue::ExternalLinkage;
420 assert(Dest->hasExternalLinkage() && Src->hasExternalLinkage() &&
421 "Unexpected linkage type!");
422 return Error(Err, "Linking globals named '" + Src->getName() +
423 "': symbol multiply defined!");
428 // Gross hack, see call sites.
429 static void CoutHack(GlobalVariable *GV1, GlobalVariable *GV2) {
430 const Type *GV1Ty = GV1->getType()->getElementType();
431 const Type *GV2Ty = GV2->getType()->getElementType();
433 if (GV1->isExternal() && isa<StructType>(GV1Ty) &&
434 GV2->hasInitializer() && GV2->hasExternalLinkage() &&
435 GV2->getInitializer()->isNullValue() && isa<ArrayType>(GV2Ty) &&
436 cast<ArrayType>(GV2Ty)->getElementType() == Type::SByteTy) {
437 GV1->setInitializer(Constant::getNullValue(GV1Ty));
438 GV2->setInitializer(0);
442 // LinkGlobals - Loop through the global variables in the src module and merge
443 // them into the dest module.
444 static bool LinkGlobals(Module *Dest, Module *Src,
445 std::map<const Value*, Value*> &ValueMap,
446 std::multimap<std::string, GlobalVariable *> &AppendingVars,
447 std::map<std::string, GlobalValue*> &GlobalsByName,
449 // We will need a module level symbol table if the src module has a module
450 // level symbol table...
451 SymbolTable *ST = (SymbolTable*)&Dest->getSymbolTable();
453 // Loop over all of the globals in the src module, mapping them over as we go
454 for (Module::giterator I = Src->gbegin(), E = Src->gend(); I != E; ++I) {
455 GlobalVariable *SGV = I;
456 GlobalVariable *DGV = 0;
457 // Check to see if may have to link the global.
458 if (SGV->hasName() && !SGV->hasInternalLinkage())
459 if (!(DGV = Dest->getGlobalVariable(SGV->getName(),
460 SGV->getType()->getElementType()))) {
461 std::map<std::string, GlobalValue*>::iterator EGV =
462 GlobalsByName.find(SGV->getName());
463 if (EGV != GlobalsByName.end())
464 DGV = dyn_cast<GlobalVariable>(EGV->second);
466 // If types don't agree due to opaque types, try to resolve them.
467 RecursiveResolveTypes(SGV->getType(), DGV->getType(),ST, "");
470 if (DGV && DGV->hasInternalLinkage())
473 assert(SGV->hasInitializer() || SGV->hasExternalLinkage() &&
474 "Global must either be external or have an initializer!");
476 // This is a gross hack to handle cin/cout until PR400 is implemented. If
477 // we are linking an external struct against a zero-initialized array of
478 // sbytes, move the initializer from the array to the struct so we keep the
485 GlobalValue::LinkageTypes NewLinkage;
487 if (GetLinkageResult(DGV, SGV, NewLinkage, LinkFromSrc, Err))
491 // No linking to be performed, simply create an identical version of the
492 // symbol over in the dest module... the initializer will be filled in
493 // later by LinkGlobalInits...
494 GlobalVariable *NewDGV =
495 new GlobalVariable(SGV->getType()->getElementType(),
496 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
497 SGV->getName(), Dest);
499 // If the LLVM runtime renamed the global, but it is an externally visible
500 // symbol, DGV must be an existing global with internal linkage. Rename
502 if (NewDGV->getName() != SGV->getName() && !NewDGV->hasInternalLinkage())
503 ForceRenaming(NewDGV, SGV->getName());
505 // Make sure to remember this mapping...
506 ValueMap.insert(std::make_pair(SGV, NewDGV));
507 if (SGV->hasAppendingLinkage())
508 // Keep track that this is an appending variable...
509 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV));
510 } else if (DGV->hasAppendingLinkage()) {
511 // No linking is performed yet. Just insert a new copy of the global, and
512 // keep track of the fact that it is an appending variable in the
513 // AppendingVars map. The name is cleared out so that no linkage is
515 GlobalVariable *NewDGV =
516 new GlobalVariable(SGV->getType()->getElementType(),
517 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
520 // Make sure to remember this mapping...
521 ValueMap.insert(std::make_pair(SGV, NewDGV));
523 // Keep track that this is an appending variable...
524 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV));
526 // Otherwise, perform the mapping as instructed by GetLinkageResult. If
527 // the types don't match, and if we are to link from the source, nuke DGV
528 // and create a new one of the appropriate type.
529 if (SGV->getType() != DGV->getType() && LinkFromSrc) {
530 GlobalVariable *NewDGV =
531 new GlobalVariable(SGV->getType()->getElementType(),
532 DGV->isConstant(), DGV->getLinkage());
533 Dest->getGlobalList().insert(DGV, NewDGV);
534 DGV->replaceAllUsesWith(ConstantExpr::getCast(NewDGV, DGV->getType()));
535 DGV->eraseFromParent();
536 NewDGV->setName(SGV->getName());
540 DGV->setLinkage(NewLinkage);
543 if (DGV->isConstant() && !SGV->isConstant())
544 return Error(Err, "Global Variable Collision on global '" +
545 SGV->getName() + "': variables differ in const'ness");
546 // Inherit const as appropriate
547 if (SGV->isConstant()) DGV->setConstant(true);
548 DGV->setInitializer(0);
550 if (SGV->isConstant() && !DGV->isConstant()) {
551 if (!DGV->isExternal())
552 return Error(Err, "Global Variable Collision on global '" +
553 SGV->getName() + "': variables differ in const'ness");
555 DGV->setConstant(true);
557 SGV->setLinkage(GlobalValue::ExternalLinkage);
558 SGV->setInitializer(0);
561 ValueMap.insert(std::make_pair(SGV,
562 ConstantExpr::getCast(DGV,
570 // LinkGlobalInits - Update the initializers in the Dest module now that all
571 // globals that may be referenced are in Dest.
572 static bool LinkGlobalInits(Module *Dest, const Module *Src,
573 std::map<const Value*, Value*> &ValueMap,
576 // Loop over all of the globals in the src module, mapping them over as we go
577 for (Module::const_giterator I = Src->gbegin(), E = Src->gend(); I != E; ++I){
578 const GlobalVariable *SGV = I;
580 if (SGV->hasInitializer()) { // Only process initialized GV's
581 // Figure out what the initializer looks like in the dest module...
583 cast<Constant>(RemapOperand(SGV->getInitializer(), ValueMap));
585 GlobalVariable *DGV = cast<GlobalVariable>(ValueMap[SGV]);
586 if (DGV->hasInitializer()) {
587 if (SGV->hasExternalLinkage()) {
588 if (DGV->getInitializer() != SInit)
589 return Error(Err, "Global Variable Collision on '" +
590 ToStr(SGV->getType(), Src) +"':%"+SGV->getName()+
591 " - Global variables have different initializers");
592 } else if (DGV->hasLinkOnceLinkage() || DGV->hasWeakLinkage()) {
593 // Nothing is required, mapped values will take the new global
595 } else if (SGV->hasLinkOnceLinkage() || SGV->hasWeakLinkage()) {
596 // Nothing is required, mapped values will take the new global
598 } else if (DGV->hasAppendingLinkage()) {
599 assert(0 && "Appending linkage unimplemented!");
601 assert(0 && "Unknown linkage!");
604 // Copy the initializer over now...
605 DGV->setInitializer(SInit);
612 // LinkFunctionProtos - Link the functions together between the two modules,
613 // without doing function bodies... this just adds external function prototypes
614 // to the Dest function...
616 static bool LinkFunctionProtos(Module *Dest, const Module *Src,
617 std::map<const Value*, Value*> &ValueMap,
618 std::map<std::string, GlobalValue*> &GlobalsByName,
620 SymbolTable *ST = (SymbolTable*)&Dest->getSymbolTable();
622 // Loop over all of the functions in the src module, mapping them over as we
624 for (Module::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) {
625 const Function *SF = I; // SrcFunction
627 if (SF->hasName() && !SF->hasInternalLinkage()) {
628 // Check to see if may have to link the function.
629 if (!(DF = Dest->getFunction(SF->getName(), SF->getFunctionType()))) {
630 std::map<std::string, GlobalValue*>::iterator EF =
631 GlobalsByName.find(SF->getName());
632 if (EF != GlobalsByName.end())
633 DF = dyn_cast<Function>(EF->second);
634 if (DF && RecursiveResolveTypes(SF->getType(), DF->getType(), ST, ""))
635 DF = 0; // FIXME: gross.
639 if (!DF || SF->hasInternalLinkage() || DF->hasInternalLinkage()) {
640 // Function does not already exist, simply insert an function signature
641 // identical to SF into the dest module...
642 Function *NewDF = new Function(SF->getFunctionType(), SF->getLinkage(),
643 SF->getName(), Dest);
645 // If the LLVM runtime renamed the function, but it is an externally
646 // visible symbol, DF must be an existing function with internal linkage.
648 if (NewDF->getName() != SF->getName() && !NewDF->hasInternalLinkage())
649 ForceRenaming(NewDF, SF->getName());
651 // ... and remember this mapping...
652 ValueMap.insert(std::make_pair(SF, NewDF));
653 } else if (SF->isExternal()) {
654 // If SF is external or if both SF & DF are external.. Just link the
655 // external functions, we aren't adding anything.
656 ValueMap.insert(std::make_pair(SF, DF));
657 } else if (DF->isExternal()) { // If DF is external but SF is not...
658 // Link the external functions, update linkage qualifiers
659 ValueMap.insert(std::make_pair(SF, DF));
660 DF->setLinkage(SF->getLinkage());
662 } else if (SF->hasWeakLinkage() || SF->hasLinkOnceLinkage()) {
663 // At this point we know that DF has LinkOnce, Weak, or External linkage.
664 ValueMap.insert(std::make_pair(SF, DF));
666 // Linkonce+Weak = Weak
667 if (DF->hasLinkOnceLinkage() && SF->hasWeakLinkage())
668 DF->setLinkage(SF->getLinkage());
670 } else if (DF->hasWeakLinkage() || DF->hasLinkOnceLinkage()) {
671 // At this point we know that SF has LinkOnce or External linkage.
672 ValueMap.insert(std::make_pair(SF, DF));
673 if (!SF->hasLinkOnceLinkage()) // Don't inherit linkonce linkage
674 DF->setLinkage(SF->getLinkage());
676 } else if (SF->getLinkage() != DF->getLinkage()) {
677 return Error(Err, "Functions named '" + SF->getName() +
678 "' have different linkage specifiers!");
679 } else if (SF->hasExternalLinkage()) {
680 // The function is defined in both modules!!
681 return Error(Err, "Function '" +
682 ToStr(SF->getFunctionType(), Src) + "':\"" +
683 SF->getName() + "\" - Function is already defined!");
685 assert(0 && "Unknown linkage configuration found!");
691 // LinkFunctionBody - Copy the source function over into the dest function and
692 // fix up references to values. At this point we know that Dest is an external
693 // function, and that Src is not.
694 static bool LinkFunctionBody(Function *Dest, Function *Src,
695 std::map<const Value*, Value*> &GlobalMap,
697 assert(Src && Dest && Dest->isExternal() && !Src->isExternal());
699 // Go through and convert function arguments over, remembering the mapping.
700 Function::aiterator DI = Dest->abegin();
701 for (Function::aiterator I = Src->abegin(), E = Src->aend();
703 DI->setName(I->getName()); // Copy the name information over...
705 // Add a mapping to our local map
706 GlobalMap.insert(std::make_pair(I, DI));
709 // Splice the body of the source function into the dest function.
710 Dest->getBasicBlockList().splice(Dest->end(), Src->getBasicBlockList());
712 // At this point, all of the instructions and values of the function are now
713 // copied over. The only problem is that they are still referencing values in
714 // the Source function as operands. Loop through all of the operands of the
715 // functions and patch them up to point to the local versions...
717 for (Function::iterator BB = Dest->begin(), BE = Dest->end(); BB != BE; ++BB)
718 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
719 for (Instruction::op_iterator OI = I->op_begin(), OE = I->op_end();
721 if (!isa<Instruction>(*OI) && !isa<BasicBlock>(*OI))
722 *OI = RemapOperand(*OI, GlobalMap);
724 // There is no need to map the arguments anymore.
725 for (Function::aiterator I = Src->abegin(), E = Src->aend(); I != E; ++I)
732 // LinkFunctionBodies - Link in the function bodies that are defined in the
733 // source module into the DestModule. This consists basically of copying the
734 // function over and fixing up references to values.
735 static bool LinkFunctionBodies(Module *Dest, 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
741 for (Module::iterator SF = Src->begin(), E = Src->end(); SF != E; ++SF) {
742 if (!SF->isExternal()) { // No body if function is external
743 Function *DF = cast<Function>(ValueMap[SF]); // Destination function
745 // DF not external SF external?
746 if (DF->isExternal()) {
747 // Only provide the function body if there isn't one already.
748 if (LinkFunctionBody(DF, SF, ValueMap, Err))
756 // LinkAppendingVars - If there were any appending global variables, link them
757 // together now. Return true on error.
758 static bool LinkAppendingVars(Module *M,
759 std::multimap<std::string, GlobalVariable *> &AppendingVars,
760 std::string *ErrorMsg) {
761 if (AppendingVars.empty()) return false; // Nothing to do.
763 // Loop over the multimap of appending vars, processing any variables with the
764 // same name, forming a new appending global variable with both of the
765 // initializers merged together, then rewrite references to the old variables
767 std::vector<Constant*> Inits;
768 while (AppendingVars.size() > 1) {
769 // Get the first two elements in the map...
770 std::multimap<std::string,
771 GlobalVariable*>::iterator Second = AppendingVars.begin(), First=Second++;
773 // If the first two elements are for different names, there is no pair...
774 // Otherwise there is a pair, so link them together...
775 if (First->first == Second->first) {
776 GlobalVariable *G1 = First->second, *G2 = Second->second;
777 const ArrayType *T1 = cast<ArrayType>(G1->getType()->getElementType());
778 const ArrayType *T2 = cast<ArrayType>(G2->getType()->getElementType());
780 // Check to see that they two arrays agree on type...
781 if (T1->getElementType() != T2->getElementType())
782 return Error(ErrorMsg,
783 "Appending variables with different element types need to be linked!");
784 if (G1->isConstant() != G2->isConstant())
785 return Error(ErrorMsg,
786 "Appending variables linked with different const'ness!");
788 unsigned NewSize = T1->getNumElements() + T2->getNumElements();
789 ArrayType *NewType = ArrayType::get(T1->getElementType(), NewSize);
791 // Create the new global variable...
793 new GlobalVariable(NewType, G1->isConstant(), G1->getLinkage(),
794 /*init*/0, First->first, M);
796 // Merge the initializer...
797 Inits.reserve(NewSize);
798 if (ConstantArray *I = dyn_cast<ConstantArray>(G1->getInitializer())) {
799 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i)
800 Inits.push_back(I->getOperand(i));
802 assert(isa<ConstantAggregateZero>(G1->getInitializer()));
803 Constant *CV = Constant::getNullValue(T1->getElementType());
804 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i)
807 if (ConstantArray *I = dyn_cast<ConstantArray>(G2->getInitializer())) {
808 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i)
809 Inits.push_back(I->getOperand(i));
811 assert(isa<ConstantAggregateZero>(G2->getInitializer()));
812 Constant *CV = Constant::getNullValue(T2->getElementType());
813 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i)
816 NG->setInitializer(ConstantArray::get(NewType, Inits));
819 // Replace any uses of the two global variables with uses of the new
822 // FIXME: This should rewrite simple/straight-forward uses such as
823 // getelementptr instructions to not use the Cast!
824 G1->replaceAllUsesWith(ConstantExpr::getCast(NG, G1->getType()));
825 G2->replaceAllUsesWith(ConstantExpr::getCast(NG, G2->getType()));
827 // Remove the two globals from the module now...
828 M->getGlobalList().erase(G1);
829 M->getGlobalList().erase(G2);
831 // Put the new global into the AppendingVars map so that we can handle
832 // linking of more than two vars...
835 AppendingVars.erase(First);
842 // LinkModules - This function links two modules together, with the resulting
843 // left module modified to be the composite of the two input modules. If an
844 // error occurs, true is returned and ErrorMsg (if not null) is set to indicate
845 // the problem. Upon failure, the Dest module could be in a modified state, and
846 // shouldn't be relied on to be consistent.
847 bool llvm::LinkModules(Module *Dest, Module *Src, std::string *ErrorMsg) {
848 assert(Dest != 0 && "Invalid Destination module");
849 assert(Src != 0 && "Invalid Source Module");
851 if (Dest->getEndianness() == Module::AnyEndianness)
852 Dest->setEndianness(Src->getEndianness());
853 if (Dest->getPointerSize() == Module::AnyPointerSize)
854 Dest->setPointerSize(Src->getPointerSize());
856 if (Src->getEndianness() != Module::AnyEndianness &&
857 Dest->getEndianness() != Src->getEndianness())
858 std::cerr << "WARNING: Linking two modules of different endianness!\n";
859 if (Src->getPointerSize() != Module::AnyPointerSize &&
860 Dest->getPointerSize() != Src->getPointerSize())
861 std::cerr << "WARNING: Linking two modules of different pointer size!\n";
863 // Update the destination module's dependent libraries list with the libraries
864 // from the source module. There's no opportunity for duplicates here as the
865 // Module ensures that duplicate insertions are discarded.
866 Module::lib_iterator SI = Src->lib_begin();
867 Module::lib_iterator SE = Src->lib_end();
869 Dest->addLibrary(*SI);
873 // LinkTypes - Go through the symbol table of the Src module and see if any
874 // types are named in the src module that are not named in the Dst module.
875 // Make sure there are no type name conflicts.
876 if (LinkTypes(Dest, Src, ErrorMsg)) return true;
878 // ValueMap - Mapping of values from what they used to be in Src, to what they
880 std::map<const Value*, Value*> ValueMap;
882 // AppendingVars - Keep track of global variables in the destination module
883 // with appending linkage. After the module is linked together, they are
884 // appended and the module is rewritten.
885 std::multimap<std::string, GlobalVariable *> AppendingVars;
887 // GlobalsByName - The LLVM SymbolTable class fights our best efforts at
888 // linking by separating globals by type. Until PR411 is fixed, we replicate
889 // it's functionality here.
890 std::map<std::string, GlobalValue*> GlobalsByName;
892 for (Module::giterator I = Dest->gbegin(), E = Dest->gend(); I != E; ++I) {
893 // Add all of the appending globals already in the Dest module to
895 if (I->hasAppendingLinkage())
896 AppendingVars.insert(std::make_pair(I->getName(), I));
898 // Keep track of all globals by name.
899 if (!I->hasInternalLinkage() && I->hasName())
900 GlobalsByName[I->getName()] = I;
903 // Keep track of all globals by name.
904 for (Module::iterator I = Dest->begin(), E = Dest->end(); I != E; ++I)
905 if (!I->hasInternalLinkage() && I->hasName())
906 GlobalsByName[I->getName()] = I;
908 // Insert all of the globals in src into the Dest module... without linking
909 // initializers (which could refer to functions not yet mapped over).
910 if (LinkGlobals(Dest, Src, ValueMap, AppendingVars, GlobalsByName, ErrorMsg))
913 // Link the functions together between the two modules, without doing function
914 // bodies... this just adds external function prototypes to the Dest
915 // function... We do this so that when we begin processing function bodies,
916 // all of the global values that may be referenced are available in our
918 if (LinkFunctionProtos(Dest, Src, ValueMap, GlobalsByName, ErrorMsg))
921 // Update the initializers in the Dest module now that all globals that may
922 // be referenced are in Dest.
923 if (LinkGlobalInits(Dest, Src, ValueMap, ErrorMsg)) return true;
925 // Link in the function bodies that are defined in the source module into the
926 // DestModule. This consists basically of copying the function over and
927 // fixing up references to values.
928 if (LinkFunctionBodies(Dest, Src, ValueMap, ErrorMsg)) return true;
930 // If there were any appending global variables, link them together now.
931 if (LinkAppendingVars(Dest, AppendingVars, ErrorMsg)) return true;
933 // If the source library's module id is in the dependent library list of the
934 // destination library, remove it since that module is now linked in.
936 modId.setFile(Src->getModuleIdentifier());
937 if (!modId.isEmpty())
938 Dest->removeLibrary(modId.getBasename());