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/Support/Streams.h"
27 #include "llvm/System/Path.h"
30 // Error - Simple wrapper function to conditionally assign to E and return true.
31 // This just makes error return conditions a little bit simpler...
32 static inline bool Error(std::string *E, const std::string &Message) {
37 // ToStr - Simple wrapper function to convert a type to a string.
38 static std::string ToStr(const Type *Ty, const Module *M) {
39 std::ostringstream OS;
40 WriteTypeSymbolic(OS, Ty, M);
45 // Function: ResolveTypes()
48 // Attempt to link the two specified types together.
51 // DestTy - The type to which we wish to resolve.
52 // SrcTy - The original type which we want to resolve.
53 // Name - The name of the type.
56 // DestST - The symbol table in which the new type should be placed.
59 // true - There is an error and the types cannot yet be linked.
62 static bool ResolveTypes(const Type *DestTy, const Type *SrcTy,
63 SymbolTable *DestST, const std::string &Name) {
64 if (DestTy == SrcTy) return false; // If already equal, noop
66 // Does the type already exist in the module?
67 if (DestTy && !isa<OpaqueType>(DestTy)) { // Yup, the type already exists...
68 if (const OpaqueType *OT = dyn_cast<OpaqueType>(SrcTy)) {
69 const_cast<OpaqueType*>(OT)->refineAbstractTypeTo(DestTy);
71 return true; // Cannot link types... neither is opaque and not-equal
73 } else { // Type not in dest module. Add it now.
74 if (DestTy) // Type _is_ in module, just opaque...
75 const_cast<OpaqueType*>(cast<OpaqueType>(DestTy))
76 ->refineAbstractTypeTo(SrcTy);
77 else if (!Name.empty())
78 DestST->insert(Name, const_cast<Type*>(SrcTy));
83 static const FunctionType *getFT(const PATypeHolder &TH) {
84 return cast<FunctionType>(TH.get());
86 static const StructType *getST(const PATypeHolder &TH) {
87 return cast<StructType>(TH.get());
90 // RecursiveResolveTypes - This is just like ResolveTypes, except that it
91 // recurses down into derived types, merging the used types if the parent types
93 static bool RecursiveResolveTypesI(const PATypeHolder &DestTy,
94 const PATypeHolder &SrcTy,
95 SymbolTable *DestST, const std::string &Name,
96 std::vector<std::pair<PATypeHolder, PATypeHolder> > &Pointers) {
97 const Type *SrcTyT = SrcTy.get();
98 const Type *DestTyT = DestTy.get();
99 if (DestTyT == SrcTyT) return false; // If already equal, noop
101 // If we found our opaque type, resolve it now!
102 if (isa<OpaqueType>(DestTyT) || isa<OpaqueType>(SrcTyT))
103 return ResolveTypes(DestTyT, SrcTyT, DestST, Name);
105 // Two types cannot be resolved together if they are of different primitive
106 // type. For example, we cannot resolve an int to a float.
107 if (DestTyT->getTypeID() != SrcTyT->getTypeID()) return true;
109 // Otherwise, resolve the used type used by this derived type...
110 switch (DestTyT->getTypeID()) {
111 case Type::FunctionTyID: {
112 if (cast<FunctionType>(DestTyT)->isVarArg() !=
113 cast<FunctionType>(SrcTyT)->isVarArg() ||
114 cast<FunctionType>(DestTyT)->getNumContainedTypes() !=
115 cast<FunctionType>(SrcTyT)->getNumContainedTypes())
117 for (unsigned i = 0, e = getFT(DestTy)->getNumContainedTypes(); i != e; ++i)
118 if (RecursiveResolveTypesI(getFT(DestTy)->getContainedType(i),
119 getFT(SrcTy)->getContainedType(i), DestST, "",
124 case Type::StructTyID: {
125 if (getST(DestTy)->getNumContainedTypes() !=
126 getST(SrcTy)->getNumContainedTypes()) return 1;
127 for (unsigned i = 0, e = getST(DestTy)->getNumContainedTypes(); i != e; ++i)
128 if (RecursiveResolveTypesI(getST(DestTy)->getContainedType(i),
129 getST(SrcTy)->getContainedType(i), DestST, "",
134 case Type::ArrayTyID: {
135 const ArrayType *DAT = cast<ArrayType>(DestTy.get());
136 const ArrayType *SAT = cast<ArrayType>(SrcTy.get());
137 if (DAT->getNumElements() != SAT->getNumElements()) return true;
138 return RecursiveResolveTypesI(DAT->getElementType(), SAT->getElementType(),
139 DestST, "", Pointers);
141 case Type::PointerTyID: {
142 // If this is a pointer type, check to see if we have already seen it. If
143 // so, we are in a recursive branch. Cut off the search now. We cannot use
144 // an associative container for this search, because the type pointers (keys
145 // in the container) change whenever types get resolved...
146 for (unsigned i = 0, e = Pointers.size(); i != e; ++i)
147 if (Pointers[i].first == DestTy)
148 return Pointers[i].second != SrcTy;
150 // Otherwise, add the current pointers to the vector to stop recursion on
152 Pointers.push_back(std::make_pair(DestTyT, SrcTyT));
154 RecursiveResolveTypesI(cast<PointerType>(DestTy.get())->getElementType(),
155 cast<PointerType>(SrcTy.get())->getElementType(),
156 DestST, "", Pointers);
160 default: assert(0 && "Unexpected type!"); return true;
164 static bool RecursiveResolveTypes(const PATypeHolder &DestTy,
165 const PATypeHolder &SrcTy,
166 SymbolTable *DestST, const std::string &Name){
167 std::vector<std::pair<PATypeHolder, PATypeHolder> > PointerTypes;
168 return RecursiveResolveTypesI(DestTy, SrcTy, DestST, Name, PointerTypes);
172 // LinkTypes - Go through the symbol table of the Src module and see if any
173 // types are named in the src module that are not named in the Dst module.
174 // Make sure there are no type name conflicts.
175 static bool LinkTypes(Module *Dest, const Module *Src, std::string *Err) {
176 SymbolTable *DestST = &Dest->getSymbolTable();
177 const SymbolTable *SrcST = &Src->getSymbolTable();
179 // Look for a type plane for Type's...
180 SymbolTable::type_const_iterator TI = SrcST->type_begin();
181 SymbolTable::type_const_iterator TE = SrcST->type_end();
182 if (TI == TE) return false; // No named types, do nothing.
184 // Some types cannot be resolved immediately because they depend on other
185 // types being resolved to each other first. This contains a list of types we
186 // are waiting to recheck.
187 std::vector<std::string> DelayedTypesToResolve;
189 for ( ; TI != TE; ++TI ) {
190 const std::string &Name = TI->first;
191 const Type *RHS = TI->second;
193 // Check to see if this type name is already in the dest module...
194 Type *Entry = DestST->lookupType(Name);
196 if (ResolveTypes(Entry, RHS, DestST, Name)) {
197 // They look different, save the types 'till later to resolve.
198 DelayedTypesToResolve.push_back(Name);
202 // Iteratively resolve types while we can...
203 while (!DelayedTypesToResolve.empty()) {
204 // Loop over all of the types, attempting to resolve them if possible...
205 unsigned OldSize = DelayedTypesToResolve.size();
207 // Try direct resolution by name...
208 for (unsigned i = 0; i != DelayedTypesToResolve.size(); ++i) {
209 const std::string &Name = DelayedTypesToResolve[i];
210 Type *T1 = SrcST->lookupType(Name);
211 Type *T2 = DestST->lookupType(Name);
212 if (!ResolveTypes(T2, T1, DestST, Name)) {
213 // We are making progress!
214 DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i);
219 // Did we not eliminate any types?
220 if (DelayedTypesToResolve.size() == OldSize) {
221 // Attempt to resolve subelements of types. This allows us to merge these
222 // two types: { int* } and { opaque* }
223 for (unsigned i = 0, e = DelayedTypesToResolve.size(); i != e; ++i) {
224 const std::string &Name = DelayedTypesToResolve[i];
225 PATypeHolder T1(SrcST->lookupType(Name));
226 PATypeHolder T2(DestST->lookupType(Name));
228 if (!RecursiveResolveTypes(T2, T1, DestST, Name)) {
229 // We are making progress!
230 DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i);
232 // Go back to the main loop, perhaps we can resolve directly by name
238 // If we STILL cannot resolve the types, then there is something wrong.
239 if (DelayedTypesToResolve.size() == OldSize) {
240 // Remove the symbol name from the destination.
241 DelayedTypesToResolve.pop_back();
250 static void PrintMap(const std::map<const Value*, Value*> &M) {
251 for (std::map<const Value*, Value*>::const_iterator I = M.begin(), E =M.end();
253 cerr << " Fr: " << (void*)I->first << " ";
255 cerr << " To: " << (void*)I->second << " ";
262 // RemapOperand - Use ValueMap to convert references from one module to another.
263 // This is somewhat sophisticated in that it can automatically handle constant
264 // references correctly as well.
265 static Value *RemapOperand(const Value *In,
266 std::map<const Value*, Value*> &ValueMap) {
267 std::map<const Value*,Value*>::const_iterator I = ValueMap.find(In);
268 if (I != ValueMap.end()) return I->second;
270 // Check to see if it's a constant that we are interesting in transforming.
272 if (const Constant *CPV = dyn_cast<Constant>(In)) {
273 if ((!isa<DerivedType>(CPV->getType()) && !isa<ConstantExpr>(CPV)) ||
274 isa<ConstantAggregateZero>(CPV))
275 return const_cast<Constant*>(CPV); // Simple constants stay identical.
277 if (const ConstantArray *CPA = dyn_cast<ConstantArray>(CPV)) {
278 std::vector<Constant*> Operands(CPA->getNumOperands());
279 for (unsigned i = 0, e = CPA->getNumOperands(); i != e; ++i)
280 Operands[i] =cast<Constant>(RemapOperand(CPA->getOperand(i), ValueMap));
281 Result = ConstantArray::get(cast<ArrayType>(CPA->getType()), Operands);
282 } else if (const ConstantStruct *CPS = dyn_cast<ConstantStruct>(CPV)) {
283 std::vector<Constant*> Operands(CPS->getNumOperands());
284 for (unsigned i = 0, e = CPS->getNumOperands(); i != e; ++i)
285 Operands[i] =cast<Constant>(RemapOperand(CPS->getOperand(i), ValueMap));
286 Result = ConstantStruct::get(cast<StructType>(CPS->getType()), Operands);
287 } else if (isa<ConstantPointerNull>(CPV) || isa<UndefValue>(CPV)) {
288 Result = const_cast<Constant*>(CPV);
289 } else if (isa<GlobalValue>(CPV)) {
290 Result = cast<Constant>(RemapOperand(CPV, ValueMap));
291 } else if (const ConstantPacked *CP = dyn_cast<ConstantPacked>(CPV)) {
292 std::vector<Constant*> Operands(CP->getNumOperands());
293 for (unsigned i = 0, e = CP->getNumOperands(); i != e; ++i)
294 Operands[i] = cast<Constant>(RemapOperand(CP->getOperand(i), ValueMap));
295 Result = ConstantPacked::get(Operands);
296 } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CPV)) {
297 std::vector<Constant*> Ops;
298 for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i)
299 Ops.push_back(cast<Constant>(RemapOperand(CE->getOperand(i),ValueMap)));
300 Result = CE->getWithOperands(Ops);
302 assert(0 && "Unknown type of derived type constant value!");
304 } else if (isa<InlineAsm>(In)) {
305 Result = const_cast<Value*>(In);
308 // Cache the mapping in our local map structure...
310 ValueMap.insert(std::make_pair(In, Result));
315 cerr << "LinkModules ValueMap: \n";
318 cerr << "Couldn't remap value: " << (void*)In << " " << *In << "\n";
319 assert(0 && "Couldn't remap value!");
323 /// ForceRenaming - The LLVM SymbolTable class autorenames globals that conflict
324 /// in the symbol table. This is good for all clients except for us. Go
325 /// through the trouble to force this back.
326 static void ForceRenaming(GlobalValue *GV, const std::string &Name) {
327 assert(GV->getName() != Name && "Can't force rename to self");
328 SymbolTable &ST = GV->getParent()->getSymbolTable();
330 // If there is a conflict, rename the conflict.
331 Value *ConflictVal = ST.lookup(GV->getType(), Name);
332 assert(ConflictVal&&"Why do we have to force rename if there is no conflic?");
333 GlobalValue *ConflictGV = cast<GlobalValue>(ConflictVal);
334 assert(ConflictGV->hasInternalLinkage() &&
335 "Not conflicting with a static global, should link instead!");
337 ConflictGV->setName(""); // Eliminate the conflict
338 GV->setName(Name); // Force the name back
339 ConflictGV->setName(Name); // This will cause ConflictGV to get renamed
340 assert(GV->getName() == Name && ConflictGV->getName() != Name &&
341 "ForceRenaming didn't work");
344 /// GetLinkageResult - This analyzes the two global values and determines what
345 /// the result will look like in the destination module. In particular, it
346 /// computes the resultant linkage type, computes whether the global in the
347 /// source should be copied over to the destination (replacing the existing
348 /// one), and computes whether this linkage is an error or not.
349 static bool GetLinkageResult(GlobalValue *Dest, GlobalValue *Src,
350 GlobalValue::LinkageTypes <, bool &LinkFromSrc,
352 assert((!Dest || !Src->hasInternalLinkage()) &&
353 "If Src has internal linkage, Dest shouldn't be set!");
355 // Linking something to nothing.
357 LT = Src->getLinkage();
358 } else if (Src->isExternal()) {
359 // If Src is external or if both Src & Drc are external.. Just link the
360 // external globals, we aren't adding anything.
361 if (Src->hasDLLImportLinkage()) {
362 // If one of GVs has DLLImport linkage, result should be dllimport'ed.
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()) ||
384 Dest->hasExternalWeakLinkage()) {
386 LT = Src->getLinkage();
389 LT = Dest->getLinkage();
391 } else if (Dest->hasWeakLinkage() || Dest->hasLinkOnceLinkage()) {
392 // At this point we know that Src has External* or DLL* linkage.
393 if (Src->hasExternalWeakLinkage()) {
395 LT = Dest->getLinkage();
398 LT = GlobalValue::ExternalLinkage;
401 assert((Dest->hasExternalLinkage() ||
402 Dest->hasDLLImportLinkage() ||
403 Dest->hasDLLExportLinkage() ||
404 Dest->hasExternalWeakLinkage()) &&
405 (Src->hasExternalLinkage() ||
406 Src->hasDLLImportLinkage() ||
407 Src->hasDLLExportLinkage() ||
408 Src->hasExternalWeakLinkage()) &&
409 "Unexpected linkage type!");
410 return Error(Err, "Linking globals named '" + Src->getName() +
411 "': symbol multiply defined!");
416 // LinkGlobals - Loop through the global variables in the src module and merge
417 // them into the dest module.
418 static bool LinkGlobals(Module *Dest, Module *Src,
419 std::map<const Value*, Value*> &ValueMap,
420 std::multimap<std::string, GlobalVariable *> &AppendingVars,
421 std::map<std::string, GlobalValue*> &GlobalsByName,
423 // We will need a module level symbol table if the src module has a module
424 // level symbol table...
425 SymbolTable *ST = (SymbolTable*)&Dest->getSymbolTable();
427 // Loop over all of the globals in the src module, mapping them over as we go
428 for (Module::global_iterator I = Src->global_begin(), E = Src->global_end();
430 GlobalVariable *SGV = I;
431 GlobalVariable *DGV = 0;
432 // Check to see if may have to link the global.
433 if (SGV->hasName() && !SGV->hasInternalLinkage())
434 if (!(DGV = Dest->getGlobalVariable(SGV->getName(),
435 SGV->getType()->getElementType()))) {
436 std::map<std::string, GlobalValue*>::iterator EGV =
437 GlobalsByName.find(SGV->getName());
438 if (EGV != GlobalsByName.end())
439 DGV = dyn_cast<GlobalVariable>(EGV->second);
441 // If types don't agree due to opaque types, try to resolve them.
442 RecursiveResolveTypes(SGV->getType(), DGV->getType(),ST, "");
445 if (DGV && DGV->hasInternalLinkage())
448 assert(SGV->hasInitializer() ||
449 SGV->hasExternalLinkage() || SGV->hasDLLImportLinkage() &&
450 "Global must either be external or have an initializer!");
452 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage;
453 bool LinkFromSrc = false;
454 if (GetLinkageResult(DGV, SGV, NewLinkage, LinkFromSrc, Err))
458 // No linking to be performed, simply create an identical version of the
459 // symbol over in the dest module... the initializer will be filled in
460 // later by LinkGlobalInits...
461 GlobalVariable *NewDGV =
462 new GlobalVariable(SGV->getType()->getElementType(),
463 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
464 SGV->getName(), Dest);
465 // Propagate alignment info.
466 NewDGV->setAlignment(SGV->getAlignment());
468 // If the LLVM runtime renamed the global, but it is an externally visible
469 // symbol, DGV must be an existing global with internal linkage. Rename
471 if (NewDGV->getName() != SGV->getName() && !NewDGV->hasInternalLinkage())
472 ForceRenaming(NewDGV, SGV->getName());
474 // Make sure to remember this mapping...
475 ValueMap.insert(std::make_pair(SGV, NewDGV));
476 if (SGV->hasAppendingLinkage())
477 // Keep track that this is an appending variable...
478 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV));
479 } else if (DGV->hasAppendingLinkage()) {
480 // No linking is performed yet. Just insert a new copy of the global, and
481 // keep track of the fact that it is an appending variable in the
482 // AppendingVars map. The name is cleared out so that no linkage is
484 GlobalVariable *NewDGV =
485 new GlobalVariable(SGV->getType()->getElementType(),
486 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
489 // Propagate alignment info.
490 NewDGV->setAlignment(std::max(DGV->getAlignment(), SGV->getAlignment()));
492 // Make sure to remember this mapping...
493 ValueMap.insert(std::make_pair(SGV, NewDGV));
495 // Keep track that this is an appending variable...
496 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV));
498 // Propagate alignment info.
499 DGV->setAlignment(std::max(DGV->getAlignment(), SGV->getAlignment()));
501 // Otherwise, perform the mapping as instructed by GetLinkageResult. If
502 // the types don't match, and if we are to link from the source, nuke DGV
503 // and create a new one of the appropriate type.
504 if (SGV->getType() != DGV->getType() && LinkFromSrc) {
505 GlobalVariable *NewDGV =
506 new GlobalVariable(SGV->getType()->getElementType(),
507 DGV->isConstant(), DGV->getLinkage());
508 NewDGV->setAlignment(DGV->getAlignment());
509 Dest->getGlobalList().insert(DGV, NewDGV);
510 DGV->replaceAllUsesWith(ConstantExpr::getCast(NewDGV, DGV->getType()));
511 DGV->eraseFromParent();
512 NewDGV->setName(SGV->getName());
516 DGV->setLinkage(NewLinkage);
519 // Inherit const as appropriate
520 DGV->setConstant(SGV->isConstant());
521 DGV->setInitializer(0);
523 if (SGV->isConstant() && !DGV->isConstant()) {
524 if (DGV->isExternal())
525 DGV->setConstant(true);
527 SGV->setLinkage(GlobalValue::ExternalLinkage);
528 SGV->setInitializer(0);
531 ValueMap.insert(std::make_pair(SGV,
532 ConstantExpr::getCast(DGV,
540 // LinkGlobalInits - Update the initializers in the Dest module now that all
541 // globals that may be referenced are in Dest.
542 static bool LinkGlobalInits(Module *Dest, const Module *Src,
543 std::map<const Value*, Value*> &ValueMap,
546 // Loop over all of the globals in the src module, mapping them over as we go
547 for (Module::const_global_iterator I = Src->global_begin(),
548 E = Src->global_end(); I != E; ++I) {
549 const GlobalVariable *SGV = I;
551 if (SGV->hasInitializer()) { // Only process initialized GV's
552 // Figure out what the initializer looks like in the dest module...
554 cast<Constant>(RemapOperand(SGV->getInitializer(), ValueMap));
556 GlobalVariable *DGV = cast<GlobalVariable>(ValueMap[SGV]);
557 if (DGV->hasInitializer()) {
558 if (SGV->hasExternalLinkage()) {
559 if (DGV->getInitializer() != SInit)
560 return Error(Err, "Global Variable Collision on '" +
561 ToStr(SGV->getType(), Src) +"':%"+SGV->getName()+
562 " - Global variables have different initializers");
563 } else if (DGV->hasLinkOnceLinkage() || DGV->hasWeakLinkage()) {
564 // Nothing is required, mapped values will take the new global
566 } else if (SGV->hasLinkOnceLinkage() || SGV->hasWeakLinkage()) {
567 // Nothing is required, mapped values will take the new global
569 } else if (DGV->hasAppendingLinkage()) {
570 assert(0 && "Appending linkage unimplemented!");
572 assert(0 && "Unknown linkage!");
575 // Copy the initializer over now...
576 DGV->setInitializer(SInit);
583 // LinkFunctionProtos - Link the functions together between the two modules,
584 // without doing function bodies... this just adds external function prototypes
585 // to the Dest function...
587 static bool LinkFunctionProtos(Module *Dest, const Module *Src,
588 std::map<const Value*, Value*> &ValueMap,
589 std::map<std::string, GlobalValue*> &GlobalsByName,
591 SymbolTable *ST = (SymbolTable*)&Dest->getSymbolTable();
593 // Loop over all of the functions in the src module, mapping them over as we
595 for (Module::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) {
596 const Function *SF = I; // SrcFunction
598 if (SF->hasName() && !SF->hasInternalLinkage()) {
599 // Check to see if may have to link the function.
600 if (!(DF = Dest->getFunction(SF->getName(), SF->getFunctionType()))) {
601 std::map<std::string, GlobalValue*>::iterator EF =
602 GlobalsByName.find(SF->getName());
603 if (EF != GlobalsByName.end())
604 DF = dyn_cast<Function>(EF->second);
605 if (DF && RecursiveResolveTypes(SF->getType(), DF->getType(), ST, ""))
606 DF = 0; // FIXME: gross.
610 if (!DF || SF->hasInternalLinkage() || DF->hasInternalLinkage()) {
611 // Function does not already exist, simply insert an function signature
612 // identical to SF into the dest module...
613 Function *NewDF = new Function(SF->getFunctionType(), SF->getLinkage(),
614 SF->getName(), Dest);
615 NewDF->setCallingConv(SF->getCallingConv());
617 // If the LLVM runtime renamed the function, but it is an externally
618 // visible symbol, DF must be an existing function with internal linkage.
620 if (NewDF->getName() != SF->getName() && !NewDF->hasInternalLinkage())
621 ForceRenaming(NewDF, SF->getName());
623 // ... and remember this mapping...
624 ValueMap.insert(std::make_pair(SF, NewDF));
625 } else if (SF->isExternal()) {
626 // If SF is external or if both SF & DF are external.. Just link the
627 // external functions, we aren't adding anything.
628 if (SF->hasDLLImportLinkage()) {
629 if (DF->isExternal()) {
630 ValueMap.insert(std::make_pair(SF, DF));
631 DF->setLinkage(SF->getLinkage());
634 ValueMap.insert(std::make_pair(SF, DF));
636 } else if (DF->isExternal() && !DF->hasDLLImportLinkage()) {
637 // If DF is external but SF is not...
638 // Link the external functions, update linkage qualifiers
639 ValueMap.insert(std::make_pair(SF, DF));
640 DF->setLinkage(SF->getLinkage());
641 } else if (SF->hasWeakLinkage() || SF->hasLinkOnceLinkage()) {
642 // At this point we know that DF has LinkOnce, Weak, or External* linkage.
643 ValueMap.insert(std::make_pair(SF, DF));
645 // Linkonce+Weak = Weak
646 // *+External Weak = *
647 if ((DF->hasLinkOnceLinkage() && SF->hasWeakLinkage()) ||
648 DF->hasExternalWeakLinkage())
649 DF->setLinkage(SF->getLinkage());
652 } else if (DF->hasWeakLinkage() || DF->hasLinkOnceLinkage()) {
653 // At this point we know that SF has LinkOnce or External* linkage.
654 ValueMap.insert(std::make_pair(SF, DF));
655 if (!SF->hasLinkOnceLinkage() && !SF->hasExternalWeakLinkage())
656 // Don't inherit linkonce & external weak linkage
657 DF->setLinkage(SF->getLinkage());
658 } else if (SF->getLinkage() != DF->getLinkage()) {
659 return Error(Err, "Functions named '" + SF->getName() +
660 "' have different linkage specifiers!");
661 } else if (SF->hasExternalLinkage()) {
662 // The function is defined in both modules!!
663 return Error(Err, "Function '" +
664 ToStr(SF->getFunctionType(), Src) + "':\"" +
665 SF->getName() + "\" - Function is already defined!");
667 assert(0 && "Unknown linkage configuration found!");
673 // LinkFunctionBody - Copy the source function over into the dest function and
674 // fix up references to values. At this point we know that Dest is an external
675 // function, and that Src is not.
676 static bool LinkFunctionBody(Function *Dest, Function *Src,
677 std::map<const Value*, Value*> &GlobalMap,
679 assert(Src && Dest && Dest->isExternal() && !Src->isExternal());
681 // Go through and convert function arguments over, remembering the mapping.
682 Function::arg_iterator DI = Dest->arg_begin();
683 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end();
685 DI->setName(I->getName()); // Copy the name information over...
687 // Add a mapping to our local map
688 GlobalMap.insert(std::make_pair(I, DI));
691 // Splice the body of the source function into the dest function.
692 Dest->getBasicBlockList().splice(Dest->end(), Src->getBasicBlockList());
694 // At this point, all of the instructions and values of the function are now
695 // copied over. The only problem is that they are still referencing values in
696 // the Source function as operands. Loop through all of the operands of the
697 // functions and patch them up to point to the local versions...
699 for (Function::iterator BB = Dest->begin(), BE = Dest->end(); BB != BE; ++BB)
700 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
701 for (Instruction::op_iterator OI = I->op_begin(), OE = I->op_end();
703 if (!isa<Instruction>(*OI) && !isa<BasicBlock>(*OI))
704 *OI = RemapOperand(*OI, GlobalMap);
706 // There is no need to map the arguments anymore.
707 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end();
715 // LinkFunctionBodies - Link in the function bodies that are defined in the
716 // source module into the DestModule. This consists basically of copying the
717 // function over and fixing up references to values.
718 static bool LinkFunctionBodies(Module *Dest, Module *Src,
719 std::map<const Value*, Value*> &ValueMap,
722 // Loop over all of the functions in the src module, mapping them over as we
724 for (Module::iterator SF = Src->begin(), E = Src->end(); SF != E; ++SF) {
725 if (!SF->isExternal()) { // No body if function is external
726 Function *DF = cast<Function>(ValueMap[SF]); // Destination function
728 // DF not external SF external?
729 if (DF->isExternal()) {
730 // Only provide the function body if there isn't one already.
731 if (LinkFunctionBody(DF, SF, ValueMap, Err))
739 // LinkAppendingVars - If there were any appending global variables, link them
740 // together now. Return true on error.
741 static bool LinkAppendingVars(Module *M,
742 std::multimap<std::string, GlobalVariable *> &AppendingVars,
743 std::string *ErrorMsg) {
744 if (AppendingVars.empty()) return false; // Nothing to do.
746 // Loop over the multimap of appending vars, processing any variables with the
747 // same name, forming a new appending global variable with both of the
748 // initializers merged together, then rewrite references to the old variables
750 std::vector<Constant*> Inits;
751 while (AppendingVars.size() > 1) {
752 // Get the first two elements in the map...
753 std::multimap<std::string,
754 GlobalVariable*>::iterator Second = AppendingVars.begin(), First=Second++;
756 // If the first two elements are for different names, there is no pair...
757 // Otherwise there is a pair, so link them together...
758 if (First->first == Second->first) {
759 GlobalVariable *G1 = First->second, *G2 = Second->second;
760 const ArrayType *T1 = cast<ArrayType>(G1->getType()->getElementType());
761 const ArrayType *T2 = cast<ArrayType>(G2->getType()->getElementType());
763 // Check to see that they two arrays agree on type...
764 if (T1->getElementType() != T2->getElementType())
765 return Error(ErrorMsg,
766 "Appending variables with different element types need to be linked!");
767 if (G1->isConstant() != G2->isConstant())
768 return Error(ErrorMsg,
769 "Appending variables linked with different const'ness!");
771 unsigned NewSize = T1->getNumElements() + T2->getNumElements();
772 ArrayType *NewType = ArrayType::get(T1->getElementType(), NewSize);
774 G1->setName(""); // Clear G1's name in case of a conflict!
776 // Create the new global variable...
778 new GlobalVariable(NewType, G1->isConstant(), G1->getLinkage(),
779 /*init*/0, First->first, M);
781 // Merge the initializer...
782 Inits.reserve(NewSize);
783 if (ConstantArray *I = dyn_cast<ConstantArray>(G1->getInitializer())) {
784 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i)
785 Inits.push_back(I->getOperand(i));
787 assert(isa<ConstantAggregateZero>(G1->getInitializer()));
788 Constant *CV = Constant::getNullValue(T1->getElementType());
789 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i)
792 if (ConstantArray *I = dyn_cast<ConstantArray>(G2->getInitializer())) {
793 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i)
794 Inits.push_back(I->getOperand(i));
796 assert(isa<ConstantAggregateZero>(G2->getInitializer()));
797 Constant *CV = Constant::getNullValue(T2->getElementType());
798 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i)
801 NG->setInitializer(ConstantArray::get(NewType, Inits));
804 // Replace any uses of the two global variables with uses of the new
807 // FIXME: This should rewrite simple/straight-forward uses such as
808 // getelementptr instructions to not use the Cast!
809 G1->replaceAllUsesWith(ConstantExpr::getCast(NG, G1->getType()));
810 G2->replaceAllUsesWith(ConstantExpr::getCast(NG, G2->getType()));
812 // Remove the two globals from the module now...
813 M->getGlobalList().erase(G1);
814 M->getGlobalList().erase(G2);
816 // Put the new global into the AppendingVars map so that we can handle
817 // linking of more than two vars...
820 AppendingVars.erase(First);
827 // LinkModules - This function links two modules together, with the resulting
828 // left module modified to be the composite of the two input modules. If an
829 // error occurs, true is returned and ErrorMsg (if not null) is set to indicate
830 // the problem. Upon failure, the Dest module could be in a modified state, and
831 // shouldn't be relied on to be consistent.
833 Linker::LinkModules(Module *Dest, Module *Src, std::string *ErrorMsg) {
834 assert(Dest != 0 && "Invalid Destination module");
835 assert(Src != 0 && "Invalid Source Module");
837 if (Dest->getEndianness() == Module::AnyEndianness)
838 Dest->setEndianness(Src->getEndianness());
839 if (Dest->getPointerSize() == Module::AnyPointerSize)
840 Dest->setPointerSize(Src->getPointerSize());
841 if (Dest->getTargetTriple().empty())
842 Dest->setTargetTriple(Src->getTargetTriple());
844 if (Src->getEndianness() != Module::AnyEndianness &&
845 Dest->getEndianness() != Src->getEndianness())
846 cerr << "WARNING: Linking two modules of different endianness!\n";
847 if (Src->getPointerSize() != Module::AnyPointerSize &&
848 Dest->getPointerSize() != Src->getPointerSize())
849 cerr << "WARNING: Linking two modules of different pointer size!\n";
850 if (!Src->getTargetTriple().empty() &&
851 Dest->getTargetTriple() != Src->getTargetTriple())
852 cerr << "WARNING: Linking two modules of different target triples!\n";
854 if (!Src->getModuleInlineAsm().empty()) {
855 if (Dest->getModuleInlineAsm().empty())
856 Dest->setModuleInlineAsm(Src->getModuleInlineAsm());
858 Dest->setModuleInlineAsm(Dest->getModuleInlineAsm()+"\n"+
859 Src->getModuleInlineAsm());
862 // Update the destination module's dependent libraries list with the libraries
863 // from the source module. There's no opportunity for duplicates here as the
864 // Module ensures that duplicate insertions are discarded.
865 Module::lib_iterator SI = Src->lib_begin();
866 Module::lib_iterator SE = Src->lib_end();
868 Dest->addLibrary(*SI);
872 // LinkTypes - Go through the symbol table of the Src module and see if any
873 // types are named in the src module that are not named in the Dst module.
874 // Make sure there are no type name conflicts.
875 if (LinkTypes(Dest, Src, ErrorMsg)) return true;
877 // ValueMap - Mapping of values from what they used to be in Src, to what they
879 std::map<const Value*, Value*> ValueMap;
881 // AppendingVars - Keep track of global variables in the destination module
882 // with appending linkage. After the module is linked together, they are
883 // appended and the module is rewritten.
884 std::multimap<std::string, GlobalVariable *> AppendingVars;
886 // GlobalsByName - The LLVM SymbolTable class fights our best efforts at
887 // linking by separating globals by type. Until PR411 is fixed, we replicate
888 // it's functionality here.
889 std::map<std::string, GlobalValue*> GlobalsByName;
891 for (Module::global_iterator I = Dest->global_begin(), E = Dest->global_end();
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.set(Src->getModuleIdentifier());
937 if (!modId.isEmpty())
938 Dest->removeLibrary(modId.getBasename());