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 if (DelayedTypesToResolve.size() == OldSize) {
241 // Remove the symbol name from the destination.
242 DelayedTypesToResolve.pop_back();
251 static void PrintMap(const std::map<const Value*, Value*> &M) {
252 for (std::map<const Value*, Value*>::const_iterator I = M.begin(), E =M.end();
254 std::cerr << " Fr: " << (void*)I->first << " ";
256 std::cerr << " To: " << (void*)I->second << " ";
263 // RemapOperand - Use ValueMap to convert references from one module to another.
264 // This is somewhat sophisticated in that it can automatically handle constant
265 // references correctly as well.
266 static Value *RemapOperand(const Value *In,
267 std::map<const Value*, Value*> &ValueMap) {
268 std::map<const Value*,Value*>::const_iterator I = ValueMap.find(In);
269 if (I != ValueMap.end()) return I->second;
271 // Check to see if it's a constant that we are interesting in transforming.
273 if (const Constant *CPV = dyn_cast<Constant>(In)) {
274 if ((!isa<DerivedType>(CPV->getType()) && !isa<ConstantExpr>(CPV)) ||
275 isa<ConstantAggregateZero>(CPV))
276 return const_cast<Constant*>(CPV); // Simple constants stay identical.
278 if (const ConstantArray *CPA = dyn_cast<ConstantArray>(CPV)) {
279 std::vector<Constant*> Operands(CPA->getNumOperands());
280 for (unsigned i = 0, e = CPA->getNumOperands(); i != e; ++i)
281 Operands[i] =cast<Constant>(RemapOperand(CPA->getOperand(i), ValueMap));
282 Result = ConstantArray::get(cast<ArrayType>(CPA->getType()), Operands);
283 } else if (const ConstantStruct *CPS = dyn_cast<ConstantStruct>(CPV)) {
284 std::vector<Constant*> Operands(CPS->getNumOperands());
285 for (unsigned i = 0, e = CPS->getNumOperands(); i != e; ++i)
286 Operands[i] =cast<Constant>(RemapOperand(CPS->getOperand(i), ValueMap));
287 Result = ConstantStruct::get(cast<StructType>(CPS->getType()), Operands);
288 } else if (isa<ConstantPointerNull>(CPV) || isa<UndefValue>(CPV)) {
289 Result = const_cast<Constant*>(CPV);
290 } else if (isa<GlobalValue>(CPV)) {
291 Result = cast<Constant>(RemapOperand(CPV, ValueMap));
292 } else if (const ConstantPacked *CP = dyn_cast<ConstantPacked>(CPV)) {
293 std::vector<Constant*> Operands(CP->getNumOperands());
294 for (unsigned i = 0, e = CP->getNumOperands(); i != e; ++i)
295 Operands[i] = cast<Constant>(RemapOperand(CP->getOperand(i), ValueMap));
296 Result = ConstantPacked::get(Operands);
297 } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CPV)) {
298 std::vector<Constant*> Ops;
299 for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i)
300 Ops.push_back(cast<Constant>(RemapOperand(CE->getOperand(i),ValueMap)));
301 Result = CE->getWithOperands(Ops);
303 assert(0 && "Unknown type of derived type constant value!");
305 } else if (isa<InlineAsm>(In)) {
306 Result = const_cast<Value*>(In);
309 // Cache the mapping in our local map structure...
311 ValueMap.insert(std::make_pair(In, Result));
316 std::cerr << "LinkModules ValueMap: \n";
319 std::cerr << "Couldn't remap value: " << (void*)In << " " << *In << "\n";
320 assert(0 && "Couldn't remap value!");
324 /// ForceRenaming - The LLVM SymbolTable class autorenames globals that conflict
325 /// in the symbol table. This is good for all clients except for us. Go
326 /// through the trouble to force this back.
327 static void ForceRenaming(GlobalValue *GV, const std::string &Name) {
328 assert(GV->getName() != Name && "Can't force rename to self");
329 SymbolTable &ST = GV->getParent()->getSymbolTable();
331 // If there is a conflict, rename the conflict.
332 Value *ConflictVal = ST.lookup(GV->getType(), Name);
333 assert(ConflictVal&&"Why do we have to force rename if there is no conflic?");
334 GlobalValue *ConflictGV = cast<GlobalValue>(ConflictVal);
335 assert(ConflictGV->hasInternalLinkage() &&
336 "Not conflicting with a static global, should link instead!");
338 ConflictGV->setName(""); // Eliminate the conflict
339 GV->setName(Name); // Force the name back
340 ConflictGV->setName(Name); // This will cause ConflictGV to get renamed
341 assert(GV->getName() == Name && ConflictGV->getName() != Name &&
342 "ForceRenaming didn't work");
345 /// GetLinkageResult - This analyzes the two global values and determines what
346 /// the result will look like in the destination module. In particular, it
347 /// computes the resultant linkage type, computes whether the global in the
348 /// source should be copied over to the destination (replacing the existing
349 /// one), and computes whether this linkage is an error or not.
350 static bool GetLinkageResult(GlobalValue *Dest, GlobalValue *Src,
351 GlobalValue::LinkageTypes <, bool &LinkFromSrc,
353 assert((!Dest || !Src->hasInternalLinkage()) &&
354 "If Src has internal linkage, Dest shouldn't be set!");
356 // Linking something to nothing.
358 LT = Src->getLinkage();
359 } else if (Src->isExternal()) {
360 // If Src is external or if both Src & Drc are external.. Just link the
361 // external globals, we aren't adding anything.
362 if (Src->hasDLLImportLinkage()) {
363 if (Dest->isExternal()) {
365 LT = Src->getLinkage();
369 LT = Dest->getLinkage();
371 } else if (Dest->isExternal() && !Dest->hasDLLImportLinkage()) {
372 // If Dest is external but Src is not:
374 LT = Src->getLinkage();
375 } else if (Src->hasAppendingLinkage() || Dest->hasAppendingLinkage()) {
376 if (Src->getLinkage() != Dest->getLinkage())
377 return Error(Err, "Linking globals named '" + Src->getName() +
378 "': can only link appending global with another appending global!");
379 LinkFromSrc = true; // Special cased.
380 LT = Src->getLinkage();
381 } else if (Src->hasWeakLinkage() || Src->hasLinkOnceLinkage()) {
382 // At this point we know that Dest has LinkOnce, External, Weak, DLL* linkage.
383 if (Dest->hasLinkOnceLinkage() && Src->hasWeakLinkage()) {
385 LT = Src->getLinkage();
388 LT = Dest->getLinkage();
390 } else if (Dest->hasWeakLinkage() || Dest->hasLinkOnceLinkage()) {
391 // At this point we know that Src has External or DLL* linkage.
393 LT = GlobalValue::ExternalLinkage;
395 assert((Dest->hasExternalLinkage() ||
396 Dest->hasDLLImportLinkage() ||
397 Dest->hasDLLExportLinkage()) &&
398 (Src->hasExternalLinkage() ||
399 Src->hasDLLImportLinkage() ||
400 Src->hasDLLExportLinkage()) &&
401 "Unexpected linkage type!");
402 return Error(Err, "Linking globals named '" + Src->getName() +
403 "': symbol multiply defined!");
408 // LinkGlobals - Loop through the global variables in the src module and merge
409 // them into the dest module.
410 static bool LinkGlobals(Module *Dest, Module *Src,
411 std::map<const Value*, Value*> &ValueMap,
412 std::multimap<std::string, GlobalVariable *> &AppendingVars,
413 std::map<std::string, GlobalValue*> &GlobalsByName,
415 // We will need a module level symbol table if the src module has a module
416 // level symbol table...
417 SymbolTable *ST = (SymbolTable*)&Dest->getSymbolTable();
419 // Loop over all of the globals in the src module, mapping them over as we go
420 for (Module::global_iterator I = Src->global_begin(), E = Src->global_end();
422 GlobalVariable *SGV = I;
423 GlobalVariable *DGV = 0;
424 // Check to see if may have to link the global.
425 if (SGV->hasName() && !SGV->hasInternalLinkage())
426 if (!(DGV = Dest->getGlobalVariable(SGV->getName(),
427 SGV->getType()->getElementType()))) {
428 std::map<std::string, GlobalValue*>::iterator EGV =
429 GlobalsByName.find(SGV->getName());
430 if (EGV != GlobalsByName.end())
431 DGV = dyn_cast<GlobalVariable>(EGV->second);
433 // If types don't agree due to opaque types, try to resolve them.
434 RecursiveResolveTypes(SGV->getType(), DGV->getType(),ST, "");
437 if (DGV && DGV->hasInternalLinkage())
440 assert(SGV->hasInitializer() ||
441 SGV->hasExternalLinkage() || SGV->hasDLLImportLinkage() &&
442 "Global must either be external or have an initializer!");
444 GlobalValue::LinkageTypes NewLinkage;
446 if (GetLinkageResult(DGV, SGV, NewLinkage, LinkFromSrc, Err))
450 // No linking to be performed, simply create an identical version of the
451 // symbol over in the dest module... the initializer will be filled in
452 // later by LinkGlobalInits...
453 GlobalVariable *NewDGV =
454 new GlobalVariable(SGV->getType()->getElementType(),
455 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
456 SGV->getName(), Dest);
457 // Propagate alignment info.
458 NewDGV->setAlignment(SGV->getAlignment());
460 // If the LLVM runtime renamed the global, but it is an externally visible
461 // symbol, DGV must be an existing global with internal linkage. Rename
463 if (NewDGV->getName() != SGV->getName() && !NewDGV->hasInternalLinkage())
464 ForceRenaming(NewDGV, SGV->getName());
466 // Make sure to remember this mapping...
467 ValueMap.insert(std::make_pair(SGV, NewDGV));
468 if (SGV->hasAppendingLinkage())
469 // Keep track that this is an appending variable...
470 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV));
471 } else if (DGV->hasAppendingLinkage()) {
472 // No linking is performed yet. Just insert a new copy of the global, and
473 // keep track of the fact that it is an appending variable in the
474 // AppendingVars map. The name is cleared out so that no linkage is
476 GlobalVariable *NewDGV =
477 new GlobalVariable(SGV->getType()->getElementType(),
478 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
481 // Propagate alignment info.
482 NewDGV->setAlignment(std::max(DGV->getAlignment(), SGV->getAlignment()));
484 // Make sure to remember this mapping...
485 ValueMap.insert(std::make_pair(SGV, NewDGV));
487 // Keep track that this is an appending variable...
488 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV));
490 // Propagate alignment info.
491 DGV->setAlignment(std::max(DGV->getAlignment(), SGV->getAlignment()));
493 // Otherwise, perform the mapping as instructed by GetLinkageResult. If
494 // the types don't match, and if we are to link from the source, nuke DGV
495 // and create a new one of the appropriate type.
496 if (SGV->getType() != DGV->getType() && LinkFromSrc) {
497 GlobalVariable *NewDGV =
498 new GlobalVariable(SGV->getType()->getElementType(),
499 DGV->isConstant(), DGV->getLinkage());
500 NewDGV->setAlignment(DGV->getAlignment());
501 Dest->getGlobalList().insert(DGV, NewDGV);
502 DGV->replaceAllUsesWith(ConstantExpr::getCast(NewDGV, DGV->getType()));
503 DGV->eraseFromParent();
504 NewDGV->setName(SGV->getName());
508 DGV->setLinkage(NewLinkage);
511 // Inherit const as appropriate
512 DGV->setConstant(SGV->isConstant());
513 DGV->setInitializer(0);
515 if (SGV->isConstant() && !DGV->isConstant()) {
516 if (DGV->isExternal())
517 DGV->setConstant(true);
519 SGV->setLinkage(GlobalValue::ExternalLinkage);
520 SGV->setInitializer(0);
523 ValueMap.insert(std::make_pair(SGV,
524 ConstantExpr::getCast(DGV,
532 // LinkGlobalInits - Update the initializers in the Dest module now that all
533 // globals that may be referenced are in Dest.
534 static bool LinkGlobalInits(Module *Dest, const Module *Src,
535 std::map<const Value*, Value*> &ValueMap,
538 // Loop over all of the globals in the src module, mapping them over as we go
539 for (Module::const_global_iterator I = Src->global_begin(),
540 E = Src->global_end(); I != E; ++I) {
541 const GlobalVariable *SGV = I;
543 if (SGV->hasInitializer()) { // Only process initialized GV's
544 // Figure out what the initializer looks like in the dest module...
546 cast<Constant>(RemapOperand(SGV->getInitializer(), ValueMap));
548 GlobalVariable *DGV = cast<GlobalVariable>(ValueMap[SGV]);
549 if (DGV->hasInitializer()) {
550 if (SGV->hasExternalLinkage()) {
551 if (DGV->getInitializer() != SInit)
552 return Error(Err, "Global Variable Collision on '" +
553 ToStr(SGV->getType(), Src) +"':%"+SGV->getName()+
554 " - Global variables have different initializers");
555 } else if (DGV->hasLinkOnceLinkage() || DGV->hasWeakLinkage()) {
556 // Nothing is required, mapped values will take the new global
558 } else if (SGV->hasLinkOnceLinkage() || SGV->hasWeakLinkage()) {
559 // Nothing is required, mapped values will take the new global
561 } else if (DGV->hasAppendingLinkage()) {
562 assert(0 && "Appending linkage unimplemented!");
564 assert(0 && "Unknown linkage!");
567 // Copy the initializer over now...
568 DGV->setInitializer(SInit);
575 // LinkFunctionProtos - Link the functions together between the two modules,
576 // without doing function bodies... this just adds external function prototypes
577 // to the Dest function...
579 static bool LinkFunctionProtos(Module *Dest, const Module *Src,
580 std::map<const Value*, Value*> &ValueMap,
581 std::map<std::string, GlobalValue*> &GlobalsByName,
583 SymbolTable *ST = (SymbolTable*)&Dest->getSymbolTable();
585 // Loop over all of the functions in the src module, mapping them over as we
587 for (Module::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) {
588 const Function *SF = I; // SrcFunction
590 if (SF->hasName() && !SF->hasInternalLinkage()) {
591 // Check to see if may have to link the function.
592 if (!(DF = Dest->getFunction(SF->getName(), SF->getFunctionType()))) {
593 std::map<std::string, GlobalValue*>::iterator EF =
594 GlobalsByName.find(SF->getName());
595 if (EF != GlobalsByName.end())
596 DF = dyn_cast<Function>(EF->second);
597 if (DF && RecursiveResolveTypes(SF->getType(), DF->getType(), ST, ""))
598 DF = 0; // FIXME: gross.
602 if (!DF || SF->hasInternalLinkage() || DF->hasInternalLinkage()) {
603 // Function does not already exist, simply insert an function signature
604 // identical to SF into the dest module...
605 Function *NewDF = new Function(SF->getFunctionType(), SF->getLinkage(),
606 SF->getName(), Dest);
607 NewDF->setCallingConv(SF->getCallingConv());
609 // If the LLVM runtime renamed the function, but it is an externally
610 // visible symbol, DF must be an existing function with internal linkage.
612 if (NewDF->getName() != SF->getName() && !NewDF->hasInternalLinkage())
613 ForceRenaming(NewDF, SF->getName());
615 // ... and remember this mapping...
616 ValueMap.insert(std::make_pair(SF, NewDF));
617 } else if (SF->isExternal()) {
618 // If SF is external or if both SF & DF are external.. Just link the
619 // external functions, we aren't adding anything.
620 if (SF->hasDLLImportLinkage()) {
621 if (DF->isExternal()) {
622 ValueMap.insert(std::make_pair(SF, DF));
623 DF->setLinkage(SF->getLinkage());
626 ValueMap.insert(std::make_pair(SF, DF));
628 } else if (DF->isExternal() && !DF->hasDLLImportLinkage()) {
629 // If DF is external but SF is not...
630 // Link the external functions, update linkage qualifiers
631 ValueMap.insert(std::make_pair(SF, DF));
632 DF->setLinkage(SF->getLinkage());
633 } else if (SF->hasWeakLinkage() || SF->hasLinkOnceLinkage()) {
634 // At this point we know that DF has LinkOnce, Weak, or External linkage.
635 ValueMap.insert(std::make_pair(SF, DF));
637 // Linkonce+Weak = Weak
638 if (DF->hasLinkOnceLinkage() && SF->hasWeakLinkage())
639 DF->setLinkage(SF->getLinkage());
641 } else if (DF->hasWeakLinkage() || DF->hasLinkOnceLinkage()) {
642 // At this point we know that SF has LinkOnce or External linkage.
643 ValueMap.insert(std::make_pair(SF, DF));
644 if (!SF->hasLinkOnceLinkage()) // Don't inherit linkonce linkage
645 DF->setLinkage(SF->getLinkage());
647 } else if (SF->getLinkage() != DF->getLinkage()) {
648 return Error(Err, "Functions named '" + SF->getName() +
649 "' have different linkage specifiers!");
650 } else if (SF->hasExternalLinkage()) {
651 // The function is defined in both modules!!
652 return Error(Err, "Function '" +
653 ToStr(SF->getFunctionType(), Src) + "':\"" +
654 SF->getName() + "\" - Function is already defined!");
656 assert(0 && "Unknown linkage configuration found!");
662 // LinkFunctionBody - Copy the source function over into the dest function and
663 // fix up references to values. At this point we know that Dest is an external
664 // function, and that Src is not.
665 static bool LinkFunctionBody(Function *Dest, Function *Src,
666 std::map<const Value*, Value*> &GlobalMap,
668 assert(Src && Dest && Dest->isExternal() && !Src->isExternal());
670 // Go through and convert function arguments over, remembering the mapping.
671 Function::arg_iterator DI = Dest->arg_begin();
672 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end();
674 DI->setName(I->getName()); // Copy the name information over...
676 // Add a mapping to our local map
677 GlobalMap.insert(std::make_pair(I, DI));
680 // Splice the body of the source function into the dest function.
681 Dest->getBasicBlockList().splice(Dest->end(), Src->getBasicBlockList());
683 // At this point, all of the instructions and values of the function are now
684 // copied over. The only problem is that they are still referencing values in
685 // the Source function as operands. Loop through all of the operands of the
686 // functions and patch them up to point to the local versions...
688 for (Function::iterator BB = Dest->begin(), BE = Dest->end(); BB != BE; ++BB)
689 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
690 for (Instruction::op_iterator OI = I->op_begin(), OE = I->op_end();
692 if (!isa<Instruction>(*OI) && !isa<BasicBlock>(*OI))
693 *OI = RemapOperand(*OI, GlobalMap);
695 // There is no need to map the arguments anymore.
696 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end();
704 // LinkFunctionBodies - Link in the function bodies that are defined in the
705 // source module into the DestModule. This consists basically of copying the
706 // function over and fixing up references to values.
707 static bool LinkFunctionBodies(Module *Dest, Module *Src,
708 std::map<const Value*, Value*> &ValueMap,
711 // Loop over all of the functions in the src module, mapping them over as we
713 for (Module::iterator SF = Src->begin(), E = Src->end(); SF != E; ++SF) {
714 if (!SF->isExternal()) { // No body if function is external
715 Function *DF = cast<Function>(ValueMap[SF]); // Destination function
717 // DF not external SF external?
718 if (DF->isExternal()) {
719 // Only provide the function body if there isn't one already.
720 if (LinkFunctionBody(DF, SF, ValueMap, Err))
728 // LinkAppendingVars - If there were any appending global variables, link them
729 // together now. Return true on error.
730 static bool LinkAppendingVars(Module *M,
731 std::multimap<std::string, GlobalVariable *> &AppendingVars,
732 std::string *ErrorMsg) {
733 if (AppendingVars.empty()) return false; // Nothing to do.
735 // Loop over the multimap of appending vars, processing any variables with the
736 // same name, forming a new appending global variable with both of the
737 // initializers merged together, then rewrite references to the old variables
739 std::vector<Constant*> Inits;
740 while (AppendingVars.size() > 1) {
741 // Get the first two elements in the map...
742 std::multimap<std::string,
743 GlobalVariable*>::iterator Second = AppendingVars.begin(), First=Second++;
745 // If the first two elements are for different names, there is no pair...
746 // Otherwise there is a pair, so link them together...
747 if (First->first == Second->first) {
748 GlobalVariable *G1 = First->second, *G2 = Second->second;
749 const ArrayType *T1 = cast<ArrayType>(G1->getType()->getElementType());
750 const ArrayType *T2 = cast<ArrayType>(G2->getType()->getElementType());
752 // Check to see that they two arrays agree on type...
753 if (T1->getElementType() != T2->getElementType())
754 return Error(ErrorMsg,
755 "Appending variables with different element types need to be linked!");
756 if (G1->isConstant() != G2->isConstant())
757 return Error(ErrorMsg,
758 "Appending variables linked with different const'ness!");
760 unsigned NewSize = T1->getNumElements() + T2->getNumElements();
761 ArrayType *NewType = ArrayType::get(T1->getElementType(), NewSize);
763 G1->setName(""); // Clear G1's name in case of a conflict!
765 // Create the new global variable...
767 new GlobalVariable(NewType, G1->isConstant(), G1->getLinkage(),
768 /*init*/0, First->first, M);
770 // Merge the initializer...
771 Inits.reserve(NewSize);
772 if (ConstantArray *I = dyn_cast<ConstantArray>(G1->getInitializer())) {
773 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i)
774 Inits.push_back(I->getOperand(i));
776 assert(isa<ConstantAggregateZero>(G1->getInitializer()));
777 Constant *CV = Constant::getNullValue(T1->getElementType());
778 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i)
781 if (ConstantArray *I = dyn_cast<ConstantArray>(G2->getInitializer())) {
782 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i)
783 Inits.push_back(I->getOperand(i));
785 assert(isa<ConstantAggregateZero>(G2->getInitializer()));
786 Constant *CV = Constant::getNullValue(T2->getElementType());
787 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i)
790 NG->setInitializer(ConstantArray::get(NewType, Inits));
793 // Replace any uses of the two global variables with uses of the new
796 // FIXME: This should rewrite simple/straight-forward uses such as
797 // getelementptr instructions to not use the Cast!
798 G1->replaceAllUsesWith(ConstantExpr::getCast(NG, G1->getType()));
799 G2->replaceAllUsesWith(ConstantExpr::getCast(NG, G2->getType()));
801 // Remove the two globals from the module now...
802 M->getGlobalList().erase(G1);
803 M->getGlobalList().erase(G2);
805 // Put the new global into the AppendingVars map so that we can handle
806 // linking of more than two vars...
809 AppendingVars.erase(First);
816 // LinkModules - This function links two modules together, with the resulting
817 // left module modified to be the composite of the two input modules. If an
818 // error occurs, true is returned and ErrorMsg (if not null) is set to indicate
819 // the problem. Upon failure, the Dest module could be in a modified state, and
820 // shouldn't be relied on to be consistent.
822 Linker::LinkModules(Module *Dest, Module *Src, std::string *ErrorMsg) {
823 assert(Dest != 0 && "Invalid Destination module");
824 assert(Src != 0 && "Invalid Source Module");
826 if (Dest->getEndianness() == Module::AnyEndianness)
827 Dest->setEndianness(Src->getEndianness());
828 if (Dest->getPointerSize() == Module::AnyPointerSize)
829 Dest->setPointerSize(Src->getPointerSize());
830 if (Dest->getTargetTriple().empty())
831 Dest->setTargetTriple(Src->getTargetTriple());
833 if (Src->getEndianness() != Module::AnyEndianness &&
834 Dest->getEndianness() != Src->getEndianness())
835 std::cerr << "WARNING: Linking two modules of different endianness!\n";
836 if (Src->getPointerSize() != Module::AnyPointerSize &&
837 Dest->getPointerSize() != Src->getPointerSize())
838 std::cerr << "WARNING: Linking two modules of different pointer size!\n";
839 if (!Src->getTargetTriple().empty() &&
840 Dest->getTargetTriple() != Src->getTargetTriple())
841 std::cerr << "WARNING: Linking two modules of different target triples!\n";
843 if (!Src->getModuleInlineAsm().empty()) {
844 if (Dest->getModuleInlineAsm().empty())
845 Dest->setModuleInlineAsm(Src->getModuleInlineAsm());
847 Dest->setModuleInlineAsm(Dest->getModuleInlineAsm()+"\n"+
848 Src->getModuleInlineAsm());
851 // Update the destination module's dependent libraries list with the libraries
852 // from the source module. There's no opportunity for duplicates here as the
853 // Module ensures that duplicate insertions are discarded.
854 Module::lib_iterator SI = Src->lib_begin();
855 Module::lib_iterator SE = Src->lib_end();
857 Dest->addLibrary(*SI);
861 // LinkTypes - Go through the symbol table of the Src module and see if any
862 // types are named in the src module that are not named in the Dst module.
863 // Make sure there are no type name conflicts.
864 if (LinkTypes(Dest, Src, ErrorMsg)) return true;
866 // ValueMap - Mapping of values from what they used to be in Src, to what they
868 std::map<const Value*, Value*> ValueMap;
870 // AppendingVars - Keep track of global variables in the destination module
871 // with appending linkage. After the module is linked together, they are
872 // appended and the module is rewritten.
873 std::multimap<std::string, GlobalVariable *> AppendingVars;
875 // GlobalsByName - The LLVM SymbolTable class fights our best efforts at
876 // linking by separating globals by type. Until PR411 is fixed, we replicate
877 // it's functionality here.
878 std::map<std::string, GlobalValue*> GlobalsByName;
880 for (Module::global_iterator I = Dest->global_begin(), E = Dest->global_end();
882 // Add all of the appending globals already in the Dest module to
884 if (I->hasAppendingLinkage())
885 AppendingVars.insert(std::make_pair(I->getName(), I));
887 // Keep track of all globals by name.
888 if (!I->hasInternalLinkage() && I->hasName())
889 GlobalsByName[I->getName()] = I;
892 // Keep track of all globals by name.
893 for (Module::iterator I = Dest->begin(), E = Dest->end(); I != E; ++I)
894 if (!I->hasInternalLinkage() && I->hasName())
895 GlobalsByName[I->getName()] = I;
897 // Insert all of the globals in src into the Dest module... without linking
898 // initializers (which could refer to functions not yet mapped over).
899 if (LinkGlobals(Dest, Src, ValueMap, AppendingVars, GlobalsByName, ErrorMsg))
902 // Link the functions together between the two modules, without doing function
903 // bodies... this just adds external function prototypes to the Dest
904 // function... We do this so that when we begin processing function bodies,
905 // all of the global values that may be referenced are available in our
907 if (LinkFunctionProtos(Dest, Src, ValueMap, GlobalsByName, ErrorMsg))
910 // Update the initializers in the Dest module now that all globals that may
911 // be referenced are in Dest.
912 if (LinkGlobalInits(Dest, Src, ValueMap, ErrorMsg)) return true;
914 // Link in the function bodies that are defined in the source module into the
915 // DestModule. This consists basically of copying the function over and
916 // fixing up references to values.
917 if (LinkFunctionBodies(Dest, Src, ValueMap, ErrorMsg)) return true;
919 // If there were any appending global variables, link them together now.
920 if (LinkAppendingVars(Dest, AppendingVars, ErrorMsg)) return true;
922 // If the source library's module id is in the dependent library list of the
923 // destination library, remove it since that module is now linked in.
925 modId.set(Src->getModuleIdentifier());
926 if (!modId.isEmpty())
927 Dest->removeLibrary(modId.getBasename());