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/TypeSymbolTable.h"
24 #include "llvm/ValueSymbolTable.h"
25 #include "llvm/Instructions.h"
26 #include "llvm/Assembly/Writer.h"
27 #include "llvm/Support/Streams.h"
28 #include "llvm/System/Path.h"
32 // Error - Simple wrapper function to conditionally assign to E and return true.
33 // This just makes error return conditions a little bit simpler...
34 static inline bool Error(std::string *E, const std::string &Message) {
39 // ToStr - Simple wrapper function to convert a type to a string.
40 static std::string ToStr(const Type *Ty, const Module *M) {
41 std::ostringstream OS;
42 WriteTypeSymbolic(OS, Ty, M);
47 // Function: ResolveTypes()
50 // Attempt to link the two specified types together.
53 // DestTy - The type to which we wish to resolve.
54 // SrcTy - The original type which we want to resolve.
55 // Name - The name of the type.
58 // DestST - The symbol table in which the new type should be placed.
61 // true - There is an error and the types cannot yet be linked.
64 static bool ResolveTypes(const Type *DestTy, const Type *SrcTy,
65 TypeSymbolTable *DestST, const std::string &Name) {
66 if (DestTy == SrcTy) return false; // If already equal, noop
68 // Does the type already exist in the module?
69 if (DestTy && !isa<OpaqueType>(DestTy)) { // Yup, the type already exists...
70 if (const OpaqueType *OT = dyn_cast<OpaqueType>(SrcTy)) {
71 const_cast<OpaqueType*>(OT)->refineAbstractTypeTo(DestTy);
73 return true; // Cannot link types... neither is opaque and not-equal
75 } else { // Type not in dest module. Add it now.
76 if (DestTy) // Type _is_ in module, just opaque...
77 const_cast<OpaqueType*>(cast<OpaqueType>(DestTy))
78 ->refineAbstractTypeTo(SrcTy);
79 else if (!Name.empty())
80 DestST->insert(Name, const_cast<Type*>(SrcTy));
85 static const FunctionType *getFT(const PATypeHolder &TH) {
86 return cast<FunctionType>(TH.get());
88 static const StructType *getST(const PATypeHolder &TH) {
89 return cast<StructType>(TH.get());
92 // RecursiveResolveTypes - This is just like ResolveTypes, except that it
93 // recurses down into derived types, merging the used types if the parent types
95 static bool RecursiveResolveTypesI(const PATypeHolder &DestTy,
96 const PATypeHolder &SrcTy,
97 TypeSymbolTable *DestST,
98 const std::string &Name,
99 std::vector<std::pair<PATypeHolder, PATypeHolder> > &Pointers) {
100 const Type *SrcTyT = SrcTy.get();
101 const Type *DestTyT = DestTy.get();
102 if (DestTyT == SrcTyT) return false; // If already equal, noop
104 // If we found our opaque type, resolve it now!
105 if (isa<OpaqueType>(DestTyT) || isa<OpaqueType>(SrcTyT))
106 return ResolveTypes(DestTyT, SrcTyT, DestST, Name);
108 // Two types cannot be resolved together if they are of different primitive
109 // type. For example, we cannot resolve an int to a float.
110 if (DestTyT->getTypeID() != SrcTyT->getTypeID()) return true;
112 // Otherwise, resolve the used type used by this derived type...
113 switch (DestTyT->getTypeID()) {
114 case Type::IntegerTyID: {
115 if (cast<IntegerType>(DestTyT)->getBitWidth() !=
116 cast<IntegerType>(SrcTyT)->getBitWidth())
120 case Type::FunctionTyID: {
121 if (cast<FunctionType>(DestTyT)->isVarArg() !=
122 cast<FunctionType>(SrcTyT)->isVarArg() ||
123 cast<FunctionType>(DestTyT)->getNumContainedTypes() !=
124 cast<FunctionType>(SrcTyT)->getNumContainedTypes())
126 for (unsigned i = 0, e = getFT(DestTy)->getNumContainedTypes(); i != e; ++i)
127 if (RecursiveResolveTypesI(getFT(DestTy)->getContainedType(i),
128 getFT(SrcTy)->getContainedType(i), DestST, "",
133 case Type::StructTyID: {
134 if (getST(DestTy)->getNumContainedTypes() !=
135 getST(SrcTy)->getNumContainedTypes()) return 1;
136 for (unsigned i = 0, e = getST(DestTy)->getNumContainedTypes(); i != e; ++i)
137 if (RecursiveResolveTypesI(getST(DestTy)->getContainedType(i),
138 getST(SrcTy)->getContainedType(i), DestST, "",
143 case Type::ArrayTyID: {
144 const ArrayType *DAT = cast<ArrayType>(DestTy.get());
145 const ArrayType *SAT = cast<ArrayType>(SrcTy.get());
146 if (DAT->getNumElements() != SAT->getNumElements()) return true;
147 return RecursiveResolveTypesI(DAT->getElementType(), SAT->getElementType(),
148 DestST, "", Pointers);
150 case Type::PointerTyID: {
151 // If this is a pointer type, check to see if we have already seen it. If
152 // so, we are in a recursive branch. Cut off the search now. We cannot use
153 // an associative container for this search, because the type pointers (keys
154 // in the container) change whenever types get resolved...
155 for (unsigned i = 0, e = Pointers.size(); i != e; ++i)
156 if (Pointers[i].first == DestTy)
157 return Pointers[i].second != SrcTy;
159 // Otherwise, add the current pointers to the vector to stop recursion on
161 Pointers.push_back(std::make_pair(DestTyT, SrcTyT));
163 RecursiveResolveTypesI(cast<PointerType>(DestTy.get())->getElementType(),
164 cast<PointerType>(SrcTy.get())->getElementType(),
165 DestST, "", Pointers);
169 default: assert(0 && "Unexpected type!"); return true;
173 static bool RecursiveResolveTypes(const PATypeHolder &DestTy,
174 const PATypeHolder &SrcTy,
175 TypeSymbolTable *DestST,
176 const std::string &Name){
177 std::vector<std::pair<PATypeHolder, PATypeHolder> > PointerTypes;
178 return RecursiveResolveTypesI(DestTy, SrcTy, DestST, Name, PointerTypes);
182 // LinkTypes - Go through the symbol table of the Src module and see if any
183 // types are named in the src module that are not named in the Dst module.
184 // Make sure there are no type name conflicts.
185 static bool LinkTypes(Module *Dest, const Module *Src, std::string *Err) {
186 TypeSymbolTable *DestST = &Dest->getTypeSymbolTable();
187 const TypeSymbolTable *SrcST = &Src->getTypeSymbolTable();
189 // Look for a type plane for Type's...
190 TypeSymbolTable::const_iterator TI = SrcST->begin();
191 TypeSymbolTable::const_iterator TE = SrcST->end();
192 if (TI == TE) return false; // No named types, do nothing.
194 // Some types cannot be resolved immediately because they depend on other
195 // types being resolved to each other first. This contains a list of types we
196 // are waiting to recheck.
197 std::vector<std::string> DelayedTypesToResolve;
199 for ( ; TI != TE; ++TI ) {
200 const std::string &Name = TI->first;
201 const Type *RHS = TI->second;
203 // Check to see if this type name is already in the dest module...
204 Type *Entry = DestST->lookup(Name);
206 if (ResolveTypes(Entry, RHS, DestST, Name)) {
207 // They look different, save the types 'till later to resolve.
208 DelayedTypesToResolve.push_back(Name);
212 // Iteratively resolve types while we can...
213 while (!DelayedTypesToResolve.empty()) {
214 // Loop over all of the types, attempting to resolve them if possible...
215 unsigned OldSize = DelayedTypesToResolve.size();
217 // Try direct resolution by name...
218 for (unsigned i = 0; i != DelayedTypesToResolve.size(); ++i) {
219 const std::string &Name = DelayedTypesToResolve[i];
220 Type *T1 = SrcST->lookup(Name);
221 Type *T2 = DestST->lookup(Name);
222 if (!ResolveTypes(T2, T1, DestST, Name)) {
223 // We are making progress!
224 DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i);
229 // Did we not eliminate any types?
230 if (DelayedTypesToResolve.size() == OldSize) {
231 // Attempt to resolve subelements of types. This allows us to merge these
232 // two types: { int* } and { opaque* }
233 for (unsigned i = 0, e = DelayedTypesToResolve.size(); i != e; ++i) {
234 const std::string &Name = DelayedTypesToResolve[i];
235 PATypeHolder T1(SrcST->lookup(Name));
236 PATypeHolder T2(DestST->lookup(Name));
238 if (!RecursiveResolveTypes(T2, T1, DestST, Name)) {
239 // We are making progress!
240 DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i);
242 // Go back to the main loop, perhaps we can resolve directly by name
248 // If we STILL cannot resolve the types, then there is something wrong.
249 if (DelayedTypesToResolve.size() == OldSize) {
250 // Remove the symbol name from the destination.
251 DelayedTypesToResolve.pop_back();
260 static void PrintMap(const std::map<const Value*, Value*> &M) {
261 for (std::map<const Value*, Value*>::const_iterator I = M.begin(), E =M.end();
263 cerr << " Fr: " << (void*)I->first << " ";
265 cerr << " To: " << (void*)I->second << " ";
272 // RemapOperand - Use ValueMap to convert constants from one module to another.
273 static Value *RemapOperand(const Value *In,
274 std::map<const Value*, Value*> &ValueMap) {
275 std::map<const Value*,Value*>::const_iterator I = ValueMap.find(In);
276 if (I != ValueMap.end())
279 // Check to see if it's a constant that we are interested in transforming.
281 if (const Constant *CPV = dyn_cast<Constant>(In)) {
282 if ((!isa<DerivedType>(CPV->getType()) && !isa<ConstantExpr>(CPV)) ||
283 isa<ConstantInt>(CPV) || isa<ConstantAggregateZero>(CPV))
284 return const_cast<Constant*>(CPV); // Simple constants stay identical.
286 if (const ConstantArray *CPA = dyn_cast<ConstantArray>(CPV)) {
287 std::vector<Constant*> Operands(CPA->getNumOperands());
288 for (unsigned i = 0, e = CPA->getNumOperands(); i != e; ++i)
289 Operands[i] =cast<Constant>(RemapOperand(CPA->getOperand(i), ValueMap));
290 Result = ConstantArray::get(cast<ArrayType>(CPA->getType()), Operands);
291 } else if (const ConstantStruct *CPS = dyn_cast<ConstantStruct>(CPV)) {
292 std::vector<Constant*> Operands(CPS->getNumOperands());
293 for (unsigned i = 0, e = CPS->getNumOperands(); i != e; ++i)
294 Operands[i] =cast<Constant>(RemapOperand(CPS->getOperand(i), ValueMap));
295 Result = ConstantStruct::get(cast<StructType>(CPS->getType()), Operands);
296 } else if (isa<ConstantPointerNull>(CPV) || isa<UndefValue>(CPV)) {
297 Result = const_cast<Constant*>(CPV);
298 } else if (const ConstantVector *CP = dyn_cast<ConstantVector>(CPV)) {
299 std::vector<Constant*> Operands(CP->getNumOperands());
300 for (unsigned i = 0, e = CP->getNumOperands(); i != e; ++i)
301 Operands[i] = cast<Constant>(RemapOperand(CP->getOperand(i), ValueMap));
302 Result = ConstantVector::get(Operands);
303 } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CPV)) {
304 std::vector<Constant*> Ops;
305 for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i)
306 Ops.push_back(cast<Constant>(RemapOperand(CE->getOperand(i),ValueMap)));
307 Result = CE->getWithOperands(Ops);
308 } else if (isa<GlobalValue>(CPV)) {
309 assert(0 && "Unmapped global?");
311 assert(0 && "Unknown type of derived type constant value!");
313 } else if (isa<InlineAsm>(In)) {
314 Result = const_cast<Value*>(In);
317 // Cache the mapping in our local map structure
319 ValueMap.insert(std::make_pair(In, Result));
324 cerr << "LinkModules ValueMap: \n";
327 cerr << "Couldn't remap value: " << (void*)In << " " << *In << "\n";
328 assert(0 && "Couldn't remap value!");
332 /// ForceRenaming - The LLVM SymbolTable class autorenames globals that conflict
333 /// in the symbol table. This is good for all clients except for us. Go
334 /// through the trouble to force this back.
335 static void ForceRenaming(GlobalValue *GV, const std::string &Name) {
336 assert(GV->getName() != Name && "Can't force rename to self");
337 ValueSymbolTable &ST = GV->getParent()->getValueSymbolTable();
339 // If there is a conflict, rename the conflict.
340 if (GlobalValue *ConflictGV = cast_or_null<GlobalValue>(ST.lookup(Name))) {
341 assert(ConflictGV->hasInternalLinkage() &&
342 "Not conflicting with a static global, should link instead!");
343 GV->takeName(ConflictGV);
344 ConflictGV->setName(Name); // This will cause ConflictGV to get renamed
345 assert(ConflictGV->getName() != Name && "ForceRenaming didn't work");
347 GV->setName(Name); // Force the name back
351 /// CopyGVAttributes - copy additional attributes (those not needed to construct
352 /// a GlobalValue) from the SrcGV to the DestGV.
353 static void CopyGVAttributes(GlobalValue *DestGV, const GlobalValue *SrcGV) {
354 // Propagate alignment, visibility and section info.
355 DestGV->setAlignment(std::max(DestGV->getAlignment(), SrcGV->getAlignment()));
356 DestGV->setSection(SrcGV->getSection());
357 DestGV->setVisibility(SrcGV->getVisibility());
358 if (const Function *SrcF = dyn_cast<Function>(SrcGV)) {
359 Function *DestF = cast<Function>(DestGV);
360 DestF->setCallingConv(SrcF->getCallingConv());
364 /// GetLinkageResult - This analyzes the two global values and determines what
365 /// the result will look like in the destination module. In particular, it
366 /// computes the resultant linkage type, computes whether the global in the
367 /// source should be copied over to the destination (replacing the existing
368 /// one), and computes whether this linkage is an error or not.
369 static bool GetLinkageResult(GlobalValue *Dest, GlobalValue *Src,
370 GlobalValue::LinkageTypes <, bool &LinkFromSrc,
372 assert((!Dest || !Src->hasInternalLinkage()) &&
373 "If Src has internal linkage, Dest shouldn't be set!");
375 // Linking something to nothing.
377 LT = Src->getLinkage();
378 } else if (Src->isDeclaration()) {
379 // If Src is external or if both Src & Drc are external.. Just link the
380 // external globals, we aren't adding anything.
381 if (Src->hasDLLImportLinkage()) {
382 // If one of GVs has DLLImport linkage, result should be dllimport'ed.
383 if (Dest->isDeclaration()) {
385 LT = Src->getLinkage();
387 } else if (Dest->hasExternalWeakLinkage()) {
388 //If the Dest is weak, use the source linkage
390 LT = Src->getLinkage();
393 LT = Dest->getLinkage();
395 } else if (Dest->isDeclaration() && !Dest->hasDLLImportLinkage()) {
396 // If Dest is external but Src is not:
398 LT = Src->getLinkage();
399 } else if (Src->hasAppendingLinkage() || Dest->hasAppendingLinkage()) {
400 if (Src->getLinkage() != Dest->getLinkage())
401 return Error(Err, "Linking globals named '" + Src->getName() +
402 "': can only link appending global with another appending global!");
403 LinkFromSrc = true; // Special cased.
404 LT = Src->getLinkage();
405 } else if (Src->hasWeakLinkage() || Src->hasLinkOnceLinkage()) {
406 // At this point we know that Dest has LinkOnce, External*, Weak, or
408 if ((Dest->hasLinkOnceLinkage() && Src->hasWeakLinkage()) ||
409 Dest->hasExternalWeakLinkage()) {
411 LT = Src->getLinkage();
414 LT = Dest->getLinkage();
416 } else if (Dest->hasWeakLinkage() || Dest->hasLinkOnceLinkage()) {
417 // At this point we know that Src has External* or DLL* linkage.
418 if (Src->hasExternalWeakLinkage()) {
420 LT = Dest->getLinkage();
423 LT = GlobalValue::ExternalLinkage;
426 assert((Dest->hasExternalLinkage() ||
427 Dest->hasDLLImportLinkage() ||
428 Dest->hasDLLExportLinkage() ||
429 Dest->hasExternalWeakLinkage()) &&
430 (Src->hasExternalLinkage() ||
431 Src->hasDLLImportLinkage() ||
432 Src->hasDLLExportLinkage() ||
433 Src->hasExternalWeakLinkage()) &&
434 "Unexpected linkage type!");
435 return Error(Err, "Linking globals named '" + Src->getName() +
436 "': symbol multiply defined!");
441 // LinkGlobals - Loop through the global variables in the src module and merge
442 // them into the dest module.
443 static bool LinkGlobals(Module *Dest, Module *Src,
444 std::map<const Value*, Value*> &ValueMap,
445 std::multimap<std::string, GlobalVariable *> &AppendingVars,
447 // Loop over all of the globals in the src module, mapping them over as we go
448 for (Module::global_iterator I = Src->global_begin(), E = Src->global_end();
450 GlobalVariable *SGV = I;
451 GlobalVariable *DGV = 0;
452 // Check to see if may have to link the global.
453 if (SGV->hasName() && !SGV->hasInternalLinkage()) {
454 DGV = Dest->getGlobalVariable(SGV->getName());
455 if (DGV && DGV->getType() != SGV->getType())
456 // If types don't agree due to opaque types, try to resolve them.
457 RecursiveResolveTypes(SGV->getType(), DGV->getType(),
458 &Dest->getTypeSymbolTable(), "");
461 if (DGV && DGV->hasInternalLinkage())
464 assert(SGV->hasInitializer() || SGV->hasExternalWeakLinkage() ||
465 SGV->hasExternalLinkage() || SGV->hasDLLImportLinkage() &&
466 "Global must either be external or have an initializer!");
468 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage;
469 bool LinkFromSrc = false;
470 if (GetLinkageResult(DGV, SGV, NewLinkage, LinkFromSrc, Err))
474 // No linking to be performed, simply create an identical version of the
475 // symbol over in the dest module... the initializer will be filled in
476 // later by LinkGlobalInits...
477 GlobalVariable *NewDGV =
478 new GlobalVariable(SGV->getType()->getElementType(),
479 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
480 SGV->getName(), Dest);
481 // Propagate alignment, visibility and section info.
482 CopyGVAttributes(NewDGV, SGV);
484 // If the LLVM runtime renamed the global, but it is an externally visible
485 // symbol, DGV must be an existing global with internal linkage. Rename
487 if (NewDGV->getName() != SGV->getName() && !NewDGV->hasInternalLinkage())
488 ForceRenaming(NewDGV, SGV->getName());
490 // Make sure to remember this mapping...
491 ValueMap.insert(std::make_pair(SGV, NewDGV));
492 if (SGV->hasAppendingLinkage())
493 // Keep track that this is an appending variable...
494 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV));
495 } else if (DGV->hasAppendingLinkage()) {
496 // No linking is performed yet. Just insert a new copy of the global, and
497 // keep track of the fact that it is an appending variable in the
498 // AppendingVars map. The name is cleared out so that no linkage is
500 GlobalVariable *NewDGV =
501 new GlobalVariable(SGV->getType()->getElementType(),
502 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
505 // Propagate alignment, section and visibility info.
506 NewDGV->setAlignment(DGV->getAlignment());
507 CopyGVAttributes(NewDGV, SGV);
509 // Make sure to remember this mapping...
510 ValueMap.insert(std::make_pair(SGV, NewDGV));
512 // Keep track that this is an appending variable...
513 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV));
515 // Propagate alignment, section, and visibility info.
516 CopyGVAttributes(DGV, SGV);
518 // Otherwise, perform the mapping as instructed by GetLinkageResult. If
519 // the types don't match, and if we are to link from the source, nuke DGV
520 // and create a new one of the appropriate type.
521 if (SGV->getType() != DGV->getType() && LinkFromSrc) {
522 GlobalVariable *NewDGV =
523 new GlobalVariable(SGV->getType()->getElementType(),
524 DGV->isConstant(), DGV->getLinkage());
525 CopyGVAttributes(NewDGV, DGV);
526 Dest->getGlobalList().insert(DGV, NewDGV);
527 DGV->replaceAllUsesWith(
528 ConstantExpr::getBitCast(NewDGV, DGV->getType()));
529 DGV->eraseFromParent();
530 NewDGV->setName(SGV->getName());
534 DGV->setLinkage(NewLinkage);
537 // Inherit const as appropriate
538 DGV->setConstant(SGV->isConstant());
539 DGV->setInitializer(0);
541 if (SGV->isConstant() && !DGV->isConstant()) {
542 if (DGV->isDeclaration())
543 DGV->setConstant(true);
545 SGV->setLinkage(GlobalValue::ExternalLinkage);
546 SGV->setInitializer(0);
550 std::make_pair(SGV, ConstantExpr::getBitCast(DGV, SGV->getType())));
557 // LinkGlobalInits - Update the initializers in the Dest module now that all
558 // globals that may be referenced are in Dest.
559 static bool LinkGlobalInits(Module *Dest, const Module *Src,
560 std::map<const Value*, Value*> &ValueMap,
563 // Loop over all of the globals in the src module, mapping them over as we go
564 for (Module::const_global_iterator I = Src->global_begin(),
565 E = Src->global_end(); I != E; ++I) {
566 const GlobalVariable *SGV = I;
568 if (SGV->hasInitializer()) { // Only process initialized GV's
569 // Figure out what the initializer looks like in the dest module...
571 cast<Constant>(RemapOperand(SGV->getInitializer(), ValueMap));
573 GlobalVariable *DGV = cast<GlobalVariable>(ValueMap[SGV]);
574 if (DGV->hasInitializer()) {
575 if (SGV->hasExternalLinkage()) {
576 if (DGV->getInitializer() != SInit)
577 return Error(Err, "Global Variable Collision on '" +
578 ToStr(SGV->getType(), Src) +"':%"+SGV->getName()+
579 " - Global variables have different initializers");
580 } else if (DGV->hasLinkOnceLinkage() || DGV->hasWeakLinkage()) {
581 // Nothing is required, mapped values will take the new global
583 } else if (SGV->hasLinkOnceLinkage() || SGV->hasWeakLinkage()) {
584 // Nothing is required, mapped values will take the new global
586 } else if (DGV->hasAppendingLinkage()) {
587 assert(0 && "Appending linkage unimplemented!");
589 assert(0 && "Unknown linkage!");
592 // Copy the initializer over now...
593 DGV->setInitializer(SInit);
600 // LinkFunctionProtos - Link the functions together between the two modules,
601 // without doing function bodies... this just adds external function prototypes
602 // to the Dest function...
604 static bool LinkFunctionProtos(Module *Dest, const Module *Src,
605 std::map<const Value*, Value*> &ValueMap,
607 // Loop over all of the functions in the src module, mapping them over
608 for (Module::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) {
609 const Function *SF = I; // SrcFunction
611 if (SF->hasName() && !SF->hasInternalLinkage()) {
612 // Check to see if may have to link the function.
613 DF = Dest->getFunction(SF->getName());
614 if (DF && SF->getType() != DF->getType())
615 // If types don't agree because of opaque, try to resolve them
616 RecursiveResolveTypes(SF->getType(), DF->getType(),
617 &Dest->getTypeSymbolTable(), "");
620 if (DF && DF->getType() != SF->getType()) {
621 if (DF->isDeclaration() && !SF->isDeclaration()) {
622 // We have a definition of the same name but different type in the
623 // source module. Copy the prototype to the destination and replace
624 // uses of the destination's prototype with the new prototype.
625 Function *NewDF = new Function(SF->getFunctionType(), SF->getLinkage(),
626 SF->getName(), Dest);
627 CopyGVAttributes(NewDF, SF);
629 // Any uses of DF need to change to NewDF, with cast
630 DF->replaceAllUsesWith(ConstantExpr::getBitCast(NewDF, DF->getType()));
632 // DF will conflict with NewDF because they both had the same. We must
633 // erase this now so ForceRenaming doesn't assert because DF might
634 // not have internal linkage.
635 DF->eraseFromParent();
637 // If the symbol table renamed the function, but it is an externally
638 // visible symbol, DF must be an existing function with internal
639 // linkage. Rename it.
640 if (NewDF->getName() != SF->getName() && !NewDF->hasInternalLinkage())
641 ForceRenaming(NewDF, SF->getName());
643 // Remember this mapping so uses in the source module get remapped
644 // later by RemapOperand.
645 ValueMap[SF] = NewDF;
646 } else if (SF->isDeclaration()) {
647 // We have two functions of the same name but different type and the
648 // source is a declaration while the destination is not. Any use of
649 // the source must be mapped to the destination, with a cast.
650 ValueMap[SF] = ConstantExpr::getBitCast(DF, SF->getType());
652 // We have two functions of the same name but different types and they
653 // are both definitions. This is an error.
654 return Error(Err, "Function '" + DF->getName() + "' defined as both '" +
655 ToStr(SF->getFunctionType(), Src) + "' and '" +
656 ToStr(DF->getFunctionType(), Dest) + "'");
658 } else if (!DF || SF->hasInternalLinkage() || DF->hasInternalLinkage()) {
659 // Function does not already exist, simply insert an function signature
660 // identical to SF into the dest module...
661 Function *NewDF = new Function(SF->getFunctionType(), SF->getLinkage(),
662 SF->getName(), Dest);
663 CopyGVAttributes(NewDF, SF);
665 // If the LLVM runtime renamed the function, but it is an externally
666 // visible symbol, DF must be an existing function with internal linkage.
668 if (NewDF->getName() != SF->getName() && !NewDF->hasInternalLinkage())
669 ForceRenaming(NewDF, SF->getName());
671 // ... and remember this mapping...
672 ValueMap.insert(std::make_pair(SF, NewDF));
673 } else if (SF->isDeclaration()) {
674 // If SF is a declaration or if both SF & DF are declarations, just link
675 // the declarations, we aren't adding anything.
676 if (SF->hasDLLImportLinkage()) {
677 if (DF->isDeclaration()) {
678 ValueMap.insert(std::make_pair(SF, DF));
679 DF->setLinkage(SF->getLinkage());
682 ValueMap.insert(std::make_pair(SF, DF));
684 } else if (DF->isDeclaration() && !DF->hasDLLImportLinkage()) {
685 // If DF is external but SF is not...
686 // Link the external functions, update linkage qualifiers
687 ValueMap.insert(std::make_pair(SF, DF));
688 DF->setLinkage(SF->getLinkage());
689 } else if (SF->hasWeakLinkage() || SF->hasLinkOnceLinkage()) {
690 // At this point we know that DF has LinkOnce, Weak, or External* linkage.
691 ValueMap.insert(std::make_pair(SF, DF));
693 // Linkonce+Weak = Weak
694 // *+External Weak = *
695 if ((DF->hasLinkOnceLinkage() && SF->hasWeakLinkage()) ||
696 DF->hasExternalWeakLinkage())
697 DF->setLinkage(SF->getLinkage());
698 } else if (DF->hasWeakLinkage() || DF->hasLinkOnceLinkage()) {
699 // At this point we know that SF has LinkOnce or External* linkage.
700 ValueMap.insert(std::make_pair(SF, DF));
701 if (!SF->hasLinkOnceLinkage() && !SF->hasExternalWeakLinkage())
702 // Don't inherit linkonce & external weak linkage
703 DF->setLinkage(SF->getLinkage());
704 } else if (SF->getLinkage() != DF->getLinkage()) {
705 return Error(Err, "Functions named '" + SF->getName() +
706 "' have different linkage specifiers!");
707 } else if (SF->hasExternalLinkage()) {
708 // The function is defined identically in both modules!!
709 return Error(Err, "Function '" +
710 ToStr(SF->getFunctionType(), Src) + "':\"" +
711 SF->getName() + "\" - Function is already defined!");
713 assert(0 && "Unknown linkage configuration found!");
719 // LinkFunctionBody - Copy the source function over into the dest function and
720 // fix up references to values. At this point we know that Dest is an external
721 // function, and that Src is not.
722 static bool LinkFunctionBody(Function *Dest, Function *Src,
723 std::map<const Value*, Value*> &ValueMap,
725 assert(Src && Dest && Dest->isDeclaration() && !Src->isDeclaration());
727 // Go through and convert function arguments over, remembering the mapping.
728 Function::arg_iterator DI = Dest->arg_begin();
729 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end();
731 DI->setName(I->getName()); // Copy the name information over...
733 // Add a mapping to our local map
734 ValueMap.insert(std::make_pair(I, DI));
737 // Splice the body of the source function into the dest function.
738 Dest->getBasicBlockList().splice(Dest->end(), Src->getBasicBlockList());
740 // At this point, all of the instructions and values of the function are now
741 // copied over. The only problem is that they are still referencing values in
742 // the Source function as operands. Loop through all of the operands of the
743 // functions and patch them up to point to the local versions...
745 for (Function::iterator BB = Dest->begin(), BE = Dest->end(); BB != BE; ++BB)
746 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
747 for (Instruction::op_iterator OI = I->op_begin(), OE = I->op_end();
749 if (!isa<Instruction>(*OI) && !isa<BasicBlock>(*OI))
750 *OI = RemapOperand(*OI, ValueMap);
752 // There is no need to map the arguments anymore.
753 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end();
761 // LinkFunctionBodies - Link in the function bodies that are defined in the
762 // source module into the DestModule. This consists basically of copying the
763 // function over and fixing up references to values.
764 static bool LinkFunctionBodies(Module *Dest, Module *Src,
765 std::map<const Value*, Value*> &ValueMap,
768 // Loop over all of the functions in the src module, mapping them over as we
770 for (Module::iterator SF = Src->begin(), E = Src->end(); SF != E; ++SF) {
771 if (!SF->isDeclaration()) { // No body if function is external
772 Function *DF = cast<Function>(ValueMap[SF]); // Destination function
774 // DF not external SF external?
775 if (DF->isDeclaration())
776 // Only provide the function body if there isn't one already.
777 if (LinkFunctionBody(DF, SF, ValueMap, Err))
784 // LinkAppendingVars - If there were any appending global variables, link them
785 // together now. Return true on error.
786 static bool LinkAppendingVars(Module *M,
787 std::multimap<std::string, GlobalVariable *> &AppendingVars,
788 std::string *ErrorMsg) {
789 if (AppendingVars.empty()) return false; // Nothing to do.
791 // Loop over the multimap of appending vars, processing any variables with the
792 // same name, forming a new appending global variable with both of the
793 // initializers merged together, then rewrite references to the old variables
795 std::vector<Constant*> Inits;
796 while (AppendingVars.size() > 1) {
797 // Get the first two elements in the map...
798 std::multimap<std::string,
799 GlobalVariable*>::iterator Second = AppendingVars.begin(), First=Second++;
801 // If the first two elements are for different names, there is no pair...
802 // Otherwise there is a pair, so link them together...
803 if (First->first == Second->first) {
804 GlobalVariable *G1 = First->second, *G2 = Second->second;
805 const ArrayType *T1 = cast<ArrayType>(G1->getType()->getElementType());
806 const ArrayType *T2 = cast<ArrayType>(G2->getType()->getElementType());
808 // Check to see that they two arrays agree on type...
809 if (T1->getElementType() != T2->getElementType())
810 return Error(ErrorMsg,
811 "Appending variables with different element types need to be linked!");
812 if (G1->isConstant() != G2->isConstant())
813 return Error(ErrorMsg,
814 "Appending variables linked with different const'ness!");
816 unsigned NewSize = T1->getNumElements() + T2->getNumElements();
817 ArrayType *NewType = ArrayType::get(T1->getElementType(), NewSize);
819 G1->setName(""); // Clear G1's name in case of a conflict!
821 // Create the new global variable...
823 new GlobalVariable(NewType, G1->isConstant(), G1->getLinkage(),
824 /*init*/0, First->first, M);
826 // Merge the initializer...
827 Inits.reserve(NewSize);
828 if (ConstantArray *I = dyn_cast<ConstantArray>(G1->getInitializer())) {
829 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i)
830 Inits.push_back(I->getOperand(i));
832 assert(isa<ConstantAggregateZero>(G1->getInitializer()));
833 Constant *CV = Constant::getNullValue(T1->getElementType());
834 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i)
837 if (ConstantArray *I = dyn_cast<ConstantArray>(G2->getInitializer())) {
838 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i)
839 Inits.push_back(I->getOperand(i));
841 assert(isa<ConstantAggregateZero>(G2->getInitializer()));
842 Constant *CV = Constant::getNullValue(T2->getElementType());
843 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i)
846 NG->setInitializer(ConstantArray::get(NewType, Inits));
849 // Replace any uses of the two global variables with uses of the new
852 // FIXME: This should rewrite simple/straight-forward uses such as
853 // getelementptr instructions to not use the Cast!
854 G1->replaceAllUsesWith(ConstantExpr::getBitCast(NG, G1->getType()));
855 G2->replaceAllUsesWith(ConstantExpr::getBitCast(NG, G2->getType()));
857 // Remove the two globals from the module now...
858 M->getGlobalList().erase(G1);
859 M->getGlobalList().erase(G2);
861 // Put the new global into the AppendingVars map so that we can handle
862 // linking of more than two vars...
865 AppendingVars.erase(First);
872 // LinkModules - This function links two modules together, with the resulting
873 // left module modified to be the composite of the two input modules. If an
874 // error occurs, true is returned and ErrorMsg (if not null) is set to indicate
875 // the problem. Upon failure, the Dest module could be in a modified state, and
876 // shouldn't be relied on to be consistent.
878 Linker::LinkModules(Module *Dest, Module *Src, std::string *ErrorMsg) {
879 assert(Dest != 0 && "Invalid Destination module");
880 assert(Src != 0 && "Invalid Source Module");
882 if (Dest->getDataLayout().empty()) {
883 if (!Src->getDataLayout().empty()) {
884 Dest->setDataLayout(Src->getDataLayout());
886 std::string DataLayout;
888 if (Dest->getEndianness() == Module::AnyEndianness)
889 if (Src->getEndianness() == Module::BigEndian)
890 DataLayout.append("E");
891 else if (Src->getEndianness() == Module::LittleEndian)
892 DataLayout.append("e");
893 if (Dest->getPointerSize() == Module::AnyPointerSize)
894 if (Src->getPointerSize() == Module::Pointer64)
895 DataLayout.append(DataLayout.length() == 0 ? "p:64:64" : "-p:64:64");
896 else if (Src->getPointerSize() == Module::Pointer32)
897 DataLayout.append(DataLayout.length() == 0 ? "p:32:32" : "-p:32:32");
898 Dest->setDataLayout(DataLayout);
902 // COpy the target triple from the source to dest if the dest's is empty
903 if (Dest->getTargetTriple().empty() && !Src->getTargetTriple().empty())
904 Dest->setTargetTriple(Src->getTargetTriple());
906 if (!Src->getDataLayout().empty() && !Dest->getDataLayout().empty() &&
907 Src->getDataLayout() != Dest->getDataLayout())
908 cerr << "WARNING: Linking two modules of different data layouts!\n";
909 if (!Src->getTargetTriple().empty() &&
910 Dest->getTargetTriple() != Src->getTargetTriple())
911 cerr << "WARNING: Linking two modules of different target triples!\n";
913 // Append the module inline asm string
914 if (!Src->getModuleInlineAsm().empty()) {
915 if (Dest->getModuleInlineAsm().empty())
916 Dest->setModuleInlineAsm(Src->getModuleInlineAsm());
918 Dest->setModuleInlineAsm(Dest->getModuleInlineAsm()+"\n"+
919 Src->getModuleInlineAsm());
922 // Update the destination module's dependent libraries list with the libraries
923 // from the source module. There's no opportunity for duplicates here as the
924 // Module ensures that duplicate insertions are discarded.
925 Module::lib_iterator SI = Src->lib_begin();
926 Module::lib_iterator SE = Src->lib_end();
928 Dest->addLibrary(*SI);
932 // LinkTypes - Go through the symbol table of the Src module and see if any
933 // types are named in the src module that are not named in the Dst module.
934 // Make sure there are no type name conflicts.
935 if (LinkTypes(Dest, Src, ErrorMsg))
938 // ValueMap - Mapping of values from what they used to be in Src, to what they
940 std::map<const Value*, Value*> ValueMap;
942 // AppendingVars - Keep track of global variables in the destination module
943 // with appending linkage. After the module is linked together, they are
944 // appended and the module is rewritten.
945 std::multimap<std::string, GlobalVariable *> AppendingVars;
946 for (Module::global_iterator I = Dest->global_begin(), E = Dest->global_end();
948 // Add all of the appending globals already in the Dest module to
950 if (I->hasAppendingLinkage())
951 AppendingVars.insert(std::make_pair(I->getName(), I));
954 // Insert all of the globals in src into the Dest module... without linking
955 // initializers (which could refer to functions not yet mapped over).
956 if (LinkGlobals(Dest, Src, ValueMap, AppendingVars, ErrorMsg))
959 // Link the functions together between the two modules, without doing function
960 // bodies... this just adds external function prototypes to the Dest
961 // function... We do this so that when we begin processing function bodies,
962 // all of the global values that may be referenced are available in our
964 if (LinkFunctionProtos(Dest, Src, ValueMap, ErrorMsg))
967 // Update the initializers in the Dest module now that all globals that may
968 // be referenced are in Dest.
969 if (LinkGlobalInits(Dest, Src, ValueMap, ErrorMsg)) return true;
971 // Link in the function bodies that are defined in the source module into the
972 // DestModule. This consists basically of copying the function over and
973 // fixing up references to values.
974 if (LinkFunctionBodies(Dest, Src, ValueMap, ErrorMsg)) return true;
976 // If there were any appending global variables, link them together now.
977 if (LinkAppendingVars(Dest, AppendingVars, ErrorMsg)) return true;
979 // If the source library's module id is in the dependent library list of the
980 // destination library, remove it since that module is now linked in.
982 modId.set(Src->getModuleIdentifier());
983 if (!modId.isEmpty())
984 Dest->removeLibrary(modId.getBasename());