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());
361 DestF->setParamAttrs(SrcF->getParamAttrs());
365 /// GetLinkageResult - This analyzes the two global values and determines what
366 /// the result will look like in the destination module. In particular, it
367 /// computes the resultant linkage type, computes whether the global in the
368 /// source should be copied over to the destination (replacing the existing
369 /// one), and computes whether this linkage is an error or not. It also performs
370 /// visibility checks: we cannot link together two symbols with different
372 static bool GetLinkageResult(GlobalValue *Dest, GlobalValue *Src,
373 GlobalValue::LinkageTypes <, bool &LinkFromSrc,
375 assert((!Dest || !Src->hasInternalLinkage()) &&
376 "If Src has internal linkage, Dest shouldn't be set!");
378 // Linking something to nothing.
380 LT = Src->getLinkage();
381 } else if (Src->isDeclaration()) {
382 // If Src is external or if both Src & Drc are external.. Just link the
383 // external globals, we aren't adding anything.
384 if (Src->hasDLLImportLinkage()) {
385 // If one of GVs has DLLImport linkage, result should be dllimport'ed.
386 if (Dest->isDeclaration()) {
388 LT = Src->getLinkage();
390 } else if (Dest->hasExternalWeakLinkage()) {
391 //If the Dest is weak, use the source linkage
393 LT = Src->getLinkage();
396 LT = Dest->getLinkage();
398 } else if (Dest->isDeclaration() && !Dest->hasDLLImportLinkage()) {
399 // If Dest is external but Src is not:
401 LT = Src->getLinkage();
402 } else if (Src->hasAppendingLinkage() || Dest->hasAppendingLinkage()) {
403 if (Src->getLinkage() != Dest->getLinkage())
404 return Error(Err, "Linking globals named '" + Src->getName() +
405 "': can only link appending global with another appending global!");
406 LinkFromSrc = true; // Special cased.
407 LT = Src->getLinkage();
408 } else if (Src->hasWeakLinkage() || Src->hasLinkOnceLinkage()) {
409 // At this point we know that Dest has LinkOnce, External*, Weak, or
411 if ((Dest->hasLinkOnceLinkage() && Src->hasWeakLinkage()) ||
412 Dest->hasExternalWeakLinkage()) {
414 LT = Src->getLinkage();
417 LT = Dest->getLinkage();
419 } else if (Dest->hasWeakLinkage() || Dest->hasLinkOnceLinkage()) {
420 // At this point we know that Src has External* or DLL* linkage.
421 if (Src->hasExternalWeakLinkage()) {
423 LT = Dest->getLinkage();
426 LT = GlobalValue::ExternalLinkage;
429 assert((Dest->hasExternalLinkage() ||
430 Dest->hasDLLImportLinkage() ||
431 Dest->hasDLLExportLinkage() ||
432 Dest->hasExternalWeakLinkage()) &&
433 (Src->hasExternalLinkage() ||
434 Src->hasDLLImportLinkage() ||
435 Src->hasDLLExportLinkage() ||
436 Src->hasExternalWeakLinkage()) &&
437 "Unexpected linkage type!");
438 return Error(Err, "Linking globals named '" + Src->getName() +
439 "': symbol multiply defined!");
443 if (Dest && Src->getVisibility() != Dest->getVisibility())
444 if (!Src->isDeclaration() && !Dest->isDeclaration())
445 return Error(Err, "Linking globals named '" + Src->getName() +
446 "': symbols have different visibilities!");
450 // LinkGlobals - Loop through the global variables in the src module and merge
451 // them into the dest module.
452 static bool LinkGlobals(Module *Dest, Module *Src,
453 std::map<const Value*, Value*> &ValueMap,
454 std::multimap<std::string, GlobalVariable *> &AppendingVars,
456 // Loop over all of the globals in the src module, mapping them over as we go
457 for (Module::global_iterator I = Src->global_begin(), E = Src->global_end();
459 GlobalVariable *SGV = I;
460 GlobalVariable *DGV = 0;
461 // Check to see if may have to link the global.
462 if (SGV->hasName() && !SGV->hasInternalLinkage()) {
463 DGV = Dest->getGlobalVariable(SGV->getName());
464 if (DGV && DGV->getType() != SGV->getType())
465 // If types don't agree due to opaque types, try to resolve them.
466 RecursiveResolveTypes(SGV->getType(), DGV->getType(),
467 &Dest->getTypeSymbolTable(), "");
470 if (DGV && DGV->hasInternalLinkage())
473 assert((SGV->hasInitializer() || SGV->hasExternalWeakLinkage() ||
474 SGV->hasExternalLinkage() || SGV->hasDLLImportLinkage()) &&
475 "Global must either be external or have an initializer!");
477 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage;
478 bool LinkFromSrc = false;
479 if (GetLinkageResult(DGV, SGV, NewLinkage, LinkFromSrc, Err))
483 // No linking to be performed, simply create an identical version of the
484 // symbol over in the dest module... the initializer will be filled in
485 // later by LinkGlobalInits...
486 GlobalVariable *NewDGV =
487 new GlobalVariable(SGV->getType()->getElementType(),
488 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
489 SGV->getName(), Dest, SGV->isThreadLocal());
490 // Propagate alignment, visibility and section info.
491 CopyGVAttributes(NewDGV, SGV);
493 // If the LLVM runtime renamed the global, but it is an externally visible
494 // symbol, DGV must be an existing global with internal linkage. Rename
496 if (NewDGV->getName() != SGV->getName() && !NewDGV->hasInternalLinkage())
497 ForceRenaming(NewDGV, SGV->getName());
499 // Make sure to remember this mapping...
500 ValueMap.insert(std::make_pair(SGV, NewDGV));
501 if (SGV->hasAppendingLinkage())
502 // Keep track that this is an appending variable...
503 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV));
504 } else if (DGV->hasAppendingLinkage()) {
505 // No linking is performed yet. Just insert a new copy of the global, and
506 // keep track of the fact that it is an appending variable in the
507 // AppendingVars map. The name is cleared out so that no linkage is
509 GlobalVariable *NewDGV =
510 new GlobalVariable(SGV->getType()->getElementType(),
511 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
512 "", Dest, SGV->isThreadLocal());
514 // Propagate alignment, section and visibility info.
515 NewDGV->setAlignment(DGV->getAlignment());
516 CopyGVAttributes(NewDGV, SGV);
518 // Make sure to remember this mapping...
519 ValueMap.insert(std::make_pair(SGV, NewDGV));
521 // Keep track that this is an appending variable...
522 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV));
524 // Propagate alignment, section, and visibility info.
525 CopyGVAttributes(DGV, SGV);
527 // Otherwise, perform the mapping as instructed by GetLinkageResult. If
528 // the types don't match, and if we are to link from the source, nuke DGV
529 // and create a new one of the appropriate type.
530 if (SGV->getType() != DGV->getType() && LinkFromSrc) {
531 GlobalVariable *NewDGV =
532 new GlobalVariable(SGV->getType()->getElementType(),
533 DGV->isConstant(), DGV->getLinkage());
534 NewDGV->setThreadLocal(DGV->isThreadLocal());
535 CopyGVAttributes(NewDGV, DGV);
536 Dest->getGlobalList().insert(DGV, NewDGV);
537 DGV->replaceAllUsesWith(
538 ConstantExpr::getBitCast(NewDGV, DGV->getType()));
539 DGV->eraseFromParent();
540 NewDGV->setName(SGV->getName());
544 DGV->setLinkage(NewLinkage);
547 // Inherit const as appropriate
548 DGV->setConstant(SGV->isConstant());
549 DGV->setInitializer(0);
551 if (SGV->isConstant() && !DGV->isConstant()) {
552 if (DGV->isDeclaration())
553 DGV->setConstant(true);
555 SGV->setLinkage(GlobalValue::ExternalLinkage);
556 SGV->setInitializer(0);
560 std::make_pair(SGV, ConstantExpr::getBitCast(DGV, SGV->getType())));
566 // LinkAlias - Loop through the alias in the src module and link them into the
568 static bool LinkAlias(Module *Dest, const Module *Src, std::string *Err) {
569 // Loop over all alias in the src module
570 for (Module::const_alias_iterator I = Src->alias_begin(),
571 E = Src->alias_end(); I != E; ++I) {
572 const GlobalAlias *GA = I;
574 GlobalValue *NewAliased = NULL;
575 const GlobalValue *Aliased = GA->getAliasedGlobal();
576 if (isa<GlobalVariable>(*Aliased))
577 NewAliased = Dest->getGlobalVariable(Aliased->getName());
578 else if (isa<Function>(*Aliased))
579 NewAliased = Dest->getFunction(Aliased->getName());
580 // FIXME: we should handle the bitcast alias.
581 assert(NewAliased && "Can't find the aliased GV.");
583 GlobalAlias *NewGA = new GlobalAlias(GA->getType(), GA->getLinkage(),
584 GA->getName(), NewAliased, Dest);
585 CopyGVAttributes(NewGA, GA);
591 // LinkGlobalInits - Update the initializers in the Dest module now that all
592 // globals that may be referenced are in Dest.
593 static bool LinkGlobalInits(Module *Dest, const Module *Src,
594 std::map<const Value*, Value*> &ValueMap,
597 // Loop over all of the globals in the src module, mapping them over as we go
598 for (Module::const_global_iterator I = Src->global_begin(),
599 E = Src->global_end(); I != E; ++I) {
600 const GlobalVariable *SGV = I;
602 if (SGV->hasInitializer()) { // Only process initialized GV's
603 // Figure out what the initializer looks like in the dest module...
605 cast<Constant>(RemapOperand(SGV->getInitializer(), ValueMap));
607 GlobalVariable *DGV = cast<GlobalVariable>(ValueMap[SGV]);
608 if (DGV->hasInitializer()) {
609 if (SGV->hasExternalLinkage()) {
610 if (DGV->getInitializer() != SInit)
611 return Error(Err, "Global Variable Collision on '" +
612 ToStr(SGV->getType(), Src) +"':%"+SGV->getName()+
613 " - Global variables have different initializers");
614 } else if (DGV->hasLinkOnceLinkage() || DGV->hasWeakLinkage()) {
615 // Nothing is required, mapped values will take the new global
617 } else if (SGV->hasLinkOnceLinkage() || SGV->hasWeakLinkage()) {
618 // Nothing is required, mapped values will take the new global
620 } else if (DGV->hasAppendingLinkage()) {
621 assert(0 && "Appending linkage unimplemented!");
623 assert(0 && "Unknown linkage!");
626 // Copy the initializer over now...
627 DGV->setInitializer(SInit);
634 // LinkFunctionProtos - Link the functions together between the two modules,
635 // without doing function bodies... this just adds external function prototypes
636 // to the Dest function...
638 static bool LinkFunctionProtos(Module *Dest, const Module *Src,
639 std::map<const Value*, Value*> &ValueMap,
641 // Loop over all of the functions in the src module, mapping them over
642 for (Module::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) {
643 const Function *SF = I; // SrcFunction
645 if (SF->hasName() && !SF->hasInternalLinkage()) {
646 // Check to see if may have to link the function.
647 DF = Dest->getFunction(SF->getName());
648 if (DF && SF->getType() != DF->getType())
649 // If types don't agree because of opaque, try to resolve them
650 RecursiveResolveTypes(SF->getType(), DF->getType(),
651 &Dest->getTypeSymbolTable(), "");
655 if (DF && !DF->hasInternalLinkage() &&
656 SF->getVisibility() != DF->getVisibility()) {
657 // If one is a prototype, ignore its visibility. Prototypes are always
658 // overridden by the definition.
659 if (!SF->isDeclaration() && !DF->isDeclaration())
660 return Error(Err, "Linking functions named '" + SF->getName() +
661 "': symbols have different visibilities!");
664 if (DF && DF->getType() != SF->getType()) {
665 if (DF->isDeclaration() && !SF->isDeclaration()) {
666 // We have a definition of the same name but different type in the
667 // source module. Copy the prototype to the destination and replace
668 // uses of the destination's prototype with the new prototype.
669 Function *NewDF = new Function(SF->getFunctionType(), SF->getLinkage(),
670 SF->getName(), Dest);
671 CopyGVAttributes(NewDF, SF);
673 // Any uses of DF need to change to NewDF, with cast
674 DF->replaceAllUsesWith(ConstantExpr::getBitCast(NewDF, DF->getType()));
676 // DF will conflict with NewDF because they both had the same. We must
677 // erase this now so ForceRenaming doesn't assert because DF might
678 // not have internal linkage.
679 DF->eraseFromParent();
681 // If the symbol table renamed the function, but it is an externally
682 // visible symbol, DF must be an existing function with internal
683 // linkage. Rename it.
684 if (NewDF->getName() != SF->getName() && !NewDF->hasInternalLinkage())
685 ForceRenaming(NewDF, SF->getName());
687 // Remember this mapping so uses in the source module get remapped
688 // later by RemapOperand.
689 ValueMap[SF] = NewDF;
690 } else if (SF->isDeclaration()) {
691 // We have two functions of the same name but different type and the
692 // source is a declaration while the destination is not. Any use of
693 // the source must be mapped to the destination, with a cast.
694 ValueMap[SF] = ConstantExpr::getBitCast(DF, SF->getType());
696 // We have two functions of the same name but different types and they
697 // are both definitions. This is an error.
698 return Error(Err, "Function '" + DF->getName() + "' defined as both '" +
699 ToStr(SF->getFunctionType(), Src) + "' and '" +
700 ToStr(DF->getFunctionType(), Dest) + "'");
702 } else if (!DF || SF->hasInternalLinkage() || DF->hasInternalLinkage()) {
703 // Function does not already exist, simply insert an function signature
704 // identical to SF into the dest module.
705 Function *NewDF = new Function(SF->getFunctionType(), SF->getLinkage(),
706 SF->getName(), Dest);
707 CopyGVAttributes(NewDF, SF);
709 // If the LLVM runtime renamed the function, but it is an externally
710 // visible symbol, DF must be an existing function with internal linkage.
712 if (NewDF->getName() != SF->getName() && !NewDF->hasInternalLinkage())
713 ForceRenaming(NewDF, SF->getName());
715 // ... and remember this mapping...
716 ValueMap.insert(std::make_pair(SF, NewDF));
717 } else if (SF->isDeclaration()) {
718 // If SF is a declaration or if both SF & DF are declarations, just link
719 // the declarations, we aren't adding anything.
720 if (SF->hasDLLImportLinkage()) {
721 if (DF->isDeclaration()) {
722 ValueMap.insert(std::make_pair(SF, DF));
723 DF->setLinkage(SF->getLinkage());
726 ValueMap.insert(std::make_pair(SF, DF));
728 } else if (DF->isDeclaration() && !DF->hasDLLImportLinkage()) {
729 // If DF is external but SF is not...
730 // Link the external functions, update linkage qualifiers
731 ValueMap.insert(std::make_pair(SF, DF));
732 DF->setLinkage(SF->getLinkage());
733 // Visibility of prototype is overridden by vis of definition.
734 DF->setVisibility(SF->getVisibility());
735 } else if (SF->hasWeakLinkage() || SF->hasLinkOnceLinkage()) {
736 // At this point we know that DF has LinkOnce, Weak, or External* linkage.
737 ValueMap.insert(std::make_pair(SF, DF));
739 // Linkonce+Weak = Weak
740 // *+External Weak = *
741 if ((DF->hasLinkOnceLinkage() && SF->hasWeakLinkage()) ||
742 DF->hasExternalWeakLinkage())
743 DF->setLinkage(SF->getLinkage());
744 } else if (DF->hasWeakLinkage() || DF->hasLinkOnceLinkage()) {
745 // At this point we know that SF has LinkOnce or External* linkage.
746 ValueMap.insert(std::make_pair(SF, DF));
747 if (!SF->hasLinkOnceLinkage() && !SF->hasExternalWeakLinkage())
748 // Don't inherit linkonce & external weak linkage
749 DF->setLinkage(SF->getLinkage());
750 } else if (SF->getLinkage() != DF->getLinkage()) {
751 return Error(Err, "Functions named '" + SF->getName() +
752 "' have different linkage specifiers!");
753 } else if (SF->hasExternalLinkage()) {
754 // The function is defined identically in both modules!!
755 return Error(Err, "Function '" +
756 ToStr(SF->getFunctionType(), Src) + "':\"" +
757 SF->getName() + "\" - Function is already defined!");
759 assert(0 && "Unknown linkage configuration found!");
765 // LinkFunctionBody - Copy the source function over into the dest function and
766 // fix up references to values. At this point we know that Dest is an external
767 // function, and that Src is not.
768 static bool LinkFunctionBody(Function *Dest, Function *Src,
769 std::map<const Value*, Value*> &ValueMap,
771 assert(Src && Dest && Dest->isDeclaration() && !Src->isDeclaration());
773 // Go through and convert function arguments over, remembering the mapping.
774 Function::arg_iterator DI = Dest->arg_begin();
775 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end();
777 DI->setName(I->getName()); // Copy the name information over...
779 // Add a mapping to our local map
780 ValueMap.insert(std::make_pair(I, DI));
783 // Splice the body of the source function into the dest function.
784 Dest->getBasicBlockList().splice(Dest->end(), Src->getBasicBlockList());
786 // At this point, all of the instructions and values of the function are now
787 // copied over. The only problem is that they are still referencing values in
788 // the Source function as operands. Loop through all of the operands of the
789 // functions and patch them up to point to the local versions...
791 for (Function::iterator BB = Dest->begin(), BE = Dest->end(); BB != BE; ++BB)
792 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
793 for (Instruction::op_iterator OI = I->op_begin(), OE = I->op_end();
795 if (!isa<Instruction>(*OI) && !isa<BasicBlock>(*OI))
796 *OI = RemapOperand(*OI, ValueMap);
798 // There is no need to map the arguments anymore.
799 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end();
807 // LinkFunctionBodies - Link in the function bodies that are defined in the
808 // source module into the DestModule. This consists basically of copying the
809 // function over and fixing up references to values.
810 static bool LinkFunctionBodies(Module *Dest, Module *Src,
811 std::map<const Value*, Value*> &ValueMap,
814 // Loop over all of the functions in the src module, mapping them over as we
816 for (Module::iterator SF = Src->begin(), E = Src->end(); SF != E; ++SF) {
817 if (!SF->isDeclaration()) { // No body if function is external
818 Function *DF = cast<Function>(ValueMap[SF]); // Destination function
820 // DF not external SF external?
821 if (DF->isDeclaration())
822 // Only provide the function body if there isn't one already.
823 if (LinkFunctionBody(DF, SF, ValueMap, Err))
830 // LinkAppendingVars - If there were any appending global variables, link them
831 // together now. Return true on error.
832 static bool LinkAppendingVars(Module *M,
833 std::multimap<std::string, GlobalVariable *> &AppendingVars,
834 std::string *ErrorMsg) {
835 if (AppendingVars.empty()) return false; // Nothing to do.
837 // Loop over the multimap of appending vars, processing any variables with the
838 // same name, forming a new appending global variable with both of the
839 // initializers merged together, then rewrite references to the old variables
841 std::vector<Constant*> Inits;
842 while (AppendingVars.size() > 1) {
843 // Get the first two elements in the map...
844 std::multimap<std::string,
845 GlobalVariable*>::iterator Second = AppendingVars.begin(), First=Second++;
847 // If the first two elements are for different names, there is no pair...
848 // Otherwise there is a pair, so link them together...
849 if (First->first == Second->first) {
850 GlobalVariable *G1 = First->second, *G2 = Second->second;
851 const ArrayType *T1 = cast<ArrayType>(G1->getType()->getElementType());
852 const ArrayType *T2 = cast<ArrayType>(G2->getType()->getElementType());
854 // Check to see that they two arrays agree on type...
855 if (T1->getElementType() != T2->getElementType())
856 return Error(ErrorMsg,
857 "Appending variables with different element types need to be linked!");
858 if (G1->isConstant() != G2->isConstant())
859 return Error(ErrorMsg,
860 "Appending variables linked with different const'ness!");
862 if (G1->getAlignment() != G2->getAlignment())
863 return Error(ErrorMsg,
864 "Appending variables with different alignment need to be linked!");
866 if (G1->getVisibility() != G2->getVisibility())
867 return Error(ErrorMsg,
868 "Appending variables with different visibility need to be linked!");
870 if (G1->getSection() != G2->getSection())
871 return Error(ErrorMsg,
872 "Appending variables with different section name need to be linked!");
874 unsigned NewSize = T1->getNumElements() + T2->getNumElements();
875 ArrayType *NewType = ArrayType::get(T1->getElementType(), NewSize);
877 G1->setName(""); // Clear G1's name in case of a conflict!
879 // Create the new global variable...
881 new GlobalVariable(NewType, G1->isConstant(), G1->getLinkage(),
882 /*init*/0, First->first, M, G1->isThreadLocal());
884 // Propagate alignment, visibility and section info.
885 CopyGVAttributes(NG, G1);
887 // Merge the initializer...
888 Inits.reserve(NewSize);
889 if (ConstantArray *I = dyn_cast<ConstantArray>(G1->getInitializer())) {
890 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i)
891 Inits.push_back(I->getOperand(i));
893 assert(isa<ConstantAggregateZero>(G1->getInitializer()));
894 Constant *CV = Constant::getNullValue(T1->getElementType());
895 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i)
898 if (ConstantArray *I = dyn_cast<ConstantArray>(G2->getInitializer())) {
899 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i)
900 Inits.push_back(I->getOperand(i));
902 assert(isa<ConstantAggregateZero>(G2->getInitializer()));
903 Constant *CV = Constant::getNullValue(T2->getElementType());
904 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i)
907 NG->setInitializer(ConstantArray::get(NewType, Inits));
910 // Replace any uses of the two global variables with uses of the new
913 // FIXME: This should rewrite simple/straight-forward uses such as
914 // getelementptr instructions to not use the Cast!
915 G1->replaceAllUsesWith(ConstantExpr::getBitCast(NG, G1->getType()));
916 G2->replaceAllUsesWith(ConstantExpr::getBitCast(NG, G2->getType()));
918 // Remove the two globals from the module now...
919 M->getGlobalList().erase(G1);
920 M->getGlobalList().erase(G2);
922 // Put the new global into the AppendingVars map so that we can handle
923 // linking of more than two vars...
926 AppendingVars.erase(First);
933 // LinkModules - This function links two modules together, with the resulting
934 // left module modified to be the composite of the two input modules. If an
935 // error occurs, true is returned and ErrorMsg (if not null) is set to indicate
936 // the problem. Upon failure, the Dest module could be in a modified state, and
937 // shouldn't be relied on to be consistent.
939 Linker::LinkModules(Module *Dest, Module *Src, std::string *ErrorMsg) {
940 assert(Dest != 0 && "Invalid Destination module");
941 assert(Src != 0 && "Invalid Source Module");
943 if (Dest->getDataLayout().empty()) {
944 if (!Src->getDataLayout().empty()) {
945 Dest->setDataLayout(Src->getDataLayout());
947 std::string DataLayout;
949 if (Dest->getEndianness() == Module::AnyEndianness)
950 if (Src->getEndianness() == Module::BigEndian)
951 DataLayout.append("E");
952 else if (Src->getEndianness() == Module::LittleEndian)
953 DataLayout.append("e");
954 if (Dest->getPointerSize() == Module::AnyPointerSize)
955 if (Src->getPointerSize() == Module::Pointer64)
956 DataLayout.append(DataLayout.length() == 0 ? "p:64:64" : "-p:64:64");
957 else if (Src->getPointerSize() == Module::Pointer32)
958 DataLayout.append(DataLayout.length() == 0 ? "p:32:32" : "-p:32:32");
959 Dest->setDataLayout(DataLayout);
963 // COpy the target triple from the source to dest if the dest's is empty
964 if (Dest->getTargetTriple().empty() && !Src->getTargetTriple().empty())
965 Dest->setTargetTriple(Src->getTargetTriple());
967 if (!Src->getDataLayout().empty() && !Dest->getDataLayout().empty() &&
968 Src->getDataLayout() != Dest->getDataLayout())
969 cerr << "WARNING: Linking two modules of different data layouts!\n";
970 if (!Src->getTargetTriple().empty() &&
971 Dest->getTargetTriple() != Src->getTargetTriple())
972 cerr << "WARNING: Linking two modules of different target triples!\n";
974 // Append the module inline asm string
975 if (!Src->getModuleInlineAsm().empty()) {
976 if (Dest->getModuleInlineAsm().empty())
977 Dest->setModuleInlineAsm(Src->getModuleInlineAsm());
979 Dest->setModuleInlineAsm(Dest->getModuleInlineAsm()+"\n"+
980 Src->getModuleInlineAsm());
983 // Update the destination module's dependent libraries list with the libraries
984 // from the source module. There's no opportunity for duplicates here as the
985 // Module ensures that duplicate insertions are discarded.
986 Module::lib_iterator SI = Src->lib_begin();
987 Module::lib_iterator SE = Src->lib_end();
989 Dest->addLibrary(*SI);
993 // LinkTypes - Go through the symbol table of the Src module and see if any
994 // types are named in the src module that are not named in the Dst module.
995 // Make sure there are no type name conflicts.
996 if (LinkTypes(Dest, Src, ErrorMsg))
999 // ValueMap - Mapping of values from what they used to be in Src, to what they
1001 std::map<const Value*, Value*> ValueMap;
1003 // AppendingVars - Keep track of global variables in the destination module
1004 // with appending linkage. After the module is linked together, they are
1005 // appended and the module is rewritten.
1006 std::multimap<std::string, GlobalVariable *> AppendingVars;
1007 for (Module::global_iterator I = Dest->global_begin(), E = Dest->global_end();
1009 // Add all of the appending globals already in the Dest module to
1011 if (I->hasAppendingLinkage())
1012 AppendingVars.insert(std::make_pair(I->getName(), I));
1015 // Insert all of the globals in src into the Dest module... without linking
1016 // initializers (which could refer to functions not yet mapped over).
1017 if (LinkGlobals(Dest, Src, ValueMap, AppendingVars, ErrorMsg))
1020 // Link the functions together between the two modules, without doing function
1021 // bodies... this just adds external function prototypes to the Dest
1022 // function... We do this so that when we begin processing function bodies,
1023 // all of the global values that may be referenced are available in our
1025 if (LinkFunctionProtos(Dest, Src, ValueMap, ErrorMsg))
1028 // Update the initializers in the Dest module now that all globals that may
1029 // be referenced are in Dest.
1030 if (LinkGlobalInits(Dest, Src, ValueMap, ErrorMsg)) return true;
1032 // Link in the function bodies that are defined in the source module into the
1033 // DestModule. This consists basically of copying the function over and
1034 // fixing up references to values.
1035 if (LinkFunctionBodies(Dest, Src, ValueMap, ErrorMsg)) return true;
1037 // If there were any appending global variables, link them together now.
1038 if (LinkAppendingVars(Dest, AppendingVars, ErrorMsg)) return true;
1040 // If there were any alias, link them now.
1041 if (LinkAlias(Dest, Src, ErrorMsg)) return true;
1043 // If the source library's module id is in the dependent library list of the
1044 // destination library, remove it since that module is now linked in.
1046 modId.set(Src->getModuleIdentifier());
1047 if (!modId.isEmpty())
1048 Dest->removeLibrary(modId.getBasename());