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/TypeSymbolTable.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()) return I->second;
278 // Check to see if it's a constant that we are interested in transforming.
280 if (const Constant *CPV = dyn_cast<Constant>(In)) {
281 if ((!isa<DerivedType>(CPV->getType()) && !isa<ConstantExpr>(CPV)) ||
282 isa<ConstantInt>(CPV) || isa<ConstantAggregateZero>(CPV))
283 return const_cast<Constant*>(CPV); // Simple constants stay identical.
285 if (const ConstantArray *CPA = dyn_cast<ConstantArray>(CPV)) {
286 std::vector<Constant*> Operands(CPA->getNumOperands());
287 for (unsigned i = 0, e = CPA->getNumOperands(); i != e; ++i)
288 Operands[i] =cast<Constant>(RemapOperand(CPA->getOperand(i), ValueMap));
289 Result = ConstantArray::get(cast<ArrayType>(CPA->getType()), Operands);
290 } else if (const ConstantStruct *CPS = dyn_cast<ConstantStruct>(CPV)) {
291 std::vector<Constant*> Operands(CPS->getNumOperands());
292 for (unsigned i = 0, e = CPS->getNumOperands(); i != e; ++i)
293 Operands[i] =cast<Constant>(RemapOperand(CPS->getOperand(i), ValueMap));
294 Result = ConstantStruct::get(cast<StructType>(CPS->getType()), Operands);
295 } else if (isa<ConstantPointerNull>(CPV) || isa<UndefValue>(CPV)) {
296 Result = const_cast<Constant*>(CPV);
297 } else if (const ConstantPacked *CP = dyn_cast<ConstantPacked>(CPV)) {
298 std::vector<Constant*> Operands(CP->getNumOperands());
299 for (unsigned i = 0, e = CP->getNumOperands(); i != e; ++i)
300 Operands[i] = cast<Constant>(RemapOperand(CP->getOperand(i), ValueMap));
301 Result = ConstantPacked::get(Operands);
302 } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CPV)) {
303 std::vector<Constant*> Ops;
304 for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i)
305 Ops.push_back(cast<Constant>(RemapOperand(CE->getOperand(i),ValueMap)));
306 Result = CE->getWithOperands(Ops);
307 } else if (isa<GlobalValue>(CPV)) {
308 assert(0 && "Unmapped global?");
310 assert(0 && "Unknown type of derived type constant value!");
312 } else if (isa<InlineAsm>(In)) {
313 Result = const_cast<Value*>(In);
316 // Cache the mapping in our local map structure
318 ValueMap.insert(std::make_pair(In, Result));
323 cerr << "LinkModules ValueMap: \n";
326 cerr << "Couldn't remap value: " << (void*)In << " " << *In << "\n";
327 assert(0 && "Couldn't remap value!");
331 /// ForceRenaming - The LLVM SymbolTable class autorenames globals that conflict
332 /// in the symbol table. This is good for all clients except for us. Go
333 /// through the trouble to force this back.
334 static void ForceRenaming(GlobalValue *GV, const std::string &Name) {
335 assert(GV->getName() != Name && "Can't force rename to self");
336 SymbolTable &ST = GV->getParent()->getValueSymbolTable();
338 // If there is a conflict, rename the conflict.
339 Value *ConflictVal = ST.lookup(GV->getType(), Name);
340 assert(ConflictVal&&"Why do we have to force rename if there is no conflic?");
341 GlobalValue *ConflictGV = cast<GlobalValue>(ConflictVal);
342 assert(ConflictGV->hasInternalLinkage() &&
343 "Not conflicting with a static global, should link instead!");
345 ConflictGV->setName(""); // Eliminate the conflict
346 GV->setName(Name); // Force the name back
347 ConflictGV->setName(Name); // This will cause ConflictGV to get renamed
348 assert(GV->getName() == Name && ConflictGV->getName() != Name &&
349 "ForceRenaming didn't work");
352 /// GetLinkageResult - This analyzes the two global values and determines what
353 /// the result will look like in the destination module. In particular, it
354 /// computes the resultant linkage type, computes whether the global in the
355 /// source should be copied over to the destination (replacing the existing
356 /// one), and computes whether this linkage is an error or not.
357 static bool GetLinkageResult(GlobalValue *Dest, GlobalValue *Src,
358 GlobalValue::LinkageTypes <, bool &LinkFromSrc,
360 assert((!Dest || !Src->hasInternalLinkage()) &&
361 "If Src has internal linkage, Dest shouldn't be set!");
363 // Linking something to nothing.
365 LT = Src->getLinkage();
366 } else if (Src->isDeclaration()) {
367 // If Src is external or if both Src & Drc are external.. Just link the
368 // external globals, we aren't adding anything.
369 if (Src->hasDLLImportLinkage()) {
370 // If one of GVs has DLLImport linkage, result should be dllimport'ed.
371 if (Dest->isDeclaration()) {
373 LT = Src->getLinkage();
375 } else if (Dest->hasExternalWeakLinkage()) {
376 //If the Dest is weak, use the source linkage
378 LT = Src->getLinkage();
381 LT = Dest->getLinkage();
383 } else if (Dest->isDeclaration() && !Dest->hasDLLImportLinkage()) {
384 // If Dest is external but Src is not:
386 LT = Src->getLinkage();
387 } else if (Src->hasAppendingLinkage() || Dest->hasAppendingLinkage()) {
388 if (Src->getLinkage() != Dest->getLinkage())
389 return Error(Err, "Linking globals named '" + Src->getName() +
390 "': can only link appending global with another appending global!");
391 LinkFromSrc = true; // Special cased.
392 LT = Src->getLinkage();
393 } else if (Src->hasWeakLinkage() || Src->hasLinkOnceLinkage()) {
394 // At this point we know that Dest has LinkOnce, External*, Weak, or
396 if ((Dest->hasLinkOnceLinkage() && Src->hasWeakLinkage()) ||
397 Dest->hasExternalWeakLinkage()) {
399 LT = Src->getLinkage();
402 LT = Dest->getLinkage();
404 } else if (Dest->hasWeakLinkage() || Dest->hasLinkOnceLinkage()) {
405 // At this point we know that Src has External* or DLL* linkage.
406 if (Src->hasExternalWeakLinkage()) {
408 LT = Dest->getLinkage();
411 LT = GlobalValue::ExternalLinkage;
414 assert((Dest->hasExternalLinkage() ||
415 Dest->hasDLLImportLinkage() ||
416 Dest->hasDLLExportLinkage() ||
417 Dest->hasExternalWeakLinkage()) &&
418 (Src->hasExternalLinkage() ||
419 Src->hasDLLImportLinkage() ||
420 Src->hasDLLExportLinkage() ||
421 Src->hasExternalWeakLinkage()) &&
422 "Unexpected linkage type!");
423 return Error(Err, "Linking globals named '" + Src->getName() +
424 "': symbol multiply defined!");
429 // LinkGlobals - Loop through the global variables in the src module and merge
430 // them into the dest module.
431 static bool LinkGlobals(Module *Dest, Module *Src,
432 std::map<const Value*, Value*> &ValueMap,
433 std::multimap<std::string, GlobalVariable *> &AppendingVars,
434 std::map<std::string, GlobalValue*> &GlobalsByName,
436 // We will need a module level symbol table if the src module has a module
437 // level symbol table...
438 TypeSymbolTable *TST = &Dest->getTypeSymbolTable();
440 // Loop over all of the globals in the src module, mapping them over as we go
441 for (Module::global_iterator I = Src->global_begin(), E = Src->global_end();
443 GlobalVariable *SGV = I;
444 GlobalVariable *DGV = 0;
445 // Check to see if may have to link the global.
446 if (SGV->hasName() && !SGV->hasInternalLinkage())
447 if (!(DGV = Dest->getGlobalVariable(SGV->getName(),
448 SGV->getType()->getElementType()))) {
449 std::map<std::string, GlobalValue*>::iterator EGV =
450 GlobalsByName.find(SGV->getName());
451 if (EGV != GlobalsByName.end())
452 DGV = dyn_cast<GlobalVariable>(EGV->second);
454 // If types don't agree due to opaque types, try to resolve them.
455 RecursiveResolveTypes(SGV->getType(), DGV->getType(), TST, "");
458 if (DGV && DGV->hasInternalLinkage())
461 assert(SGV->hasInitializer() || SGV->hasExternalWeakLinkage() ||
462 SGV->hasExternalLinkage() || SGV->hasDLLImportLinkage() &&
463 "Global must either be external or have an initializer!");
465 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage;
466 bool LinkFromSrc = false;
467 if (GetLinkageResult(DGV, SGV, NewLinkage, LinkFromSrc, Err))
471 // No linking to be performed, simply create an identical version of the
472 // symbol over in the dest module... the initializer will be filled in
473 // later by LinkGlobalInits...
474 GlobalVariable *NewDGV =
475 new GlobalVariable(SGV->getType()->getElementType(),
476 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
477 SGV->getName(), Dest);
478 // Propagate alignment, visibility and section info.
479 NewDGV->setAlignment(SGV->getAlignment());
480 NewDGV->setSection(SGV->getSection());
481 NewDGV->setVisibility(SGV->getVisibility());
483 // If the LLVM runtime renamed the global, but it is an externally visible
484 // symbol, DGV must be an existing global with internal linkage. Rename
486 if (NewDGV->getName() != SGV->getName() && !NewDGV->hasInternalLinkage())
487 ForceRenaming(NewDGV, SGV->getName());
489 // Make sure to remember this mapping...
490 ValueMap.insert(std::make_pair(SGV, NewDGV));
491 if (SGV->hasAppendingLinkage())
492 // Keep track that this is an appending variable...
493 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV));
494 } else if (DGV->hasAppendingLinkage()) {
495 // No linking is performed yet. Just insert a new copy of the global, and
496 // keep track of the fact that it is an appending variable in the
497 // AppendingVars map. The name is cleared out so that no linkage is
499 GlobalVariable *NewDGV =
500 new GlobalVariable(SGV->getType()->getElementType(),
501 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
504 // Propagate alignment, section and visibility info.
505 NewDGV->setAlignment(std::max(DGV->getAlignment(), SGV->getAlignment()));
506 NewDGV->setSection(SGV->getSection());
507 NewDGV->setVisibility(SGV->getVisibility());
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 DGV->setAlignment(std::max(DGV->getAlignment(), SGV->getAlignment()));
517 DGV->setSection(SGV->getSection());
518 DGV->setVisibility(SGV->getVisibility());
520 // Otherwise, perform the mapping as instructed by GetLinkageResult. If
521 // the types don't match, and if we are to link from the source, nuke DGV
522 // and create a new one of the appropriate type.
523 if (SGV->getType() != DGV->getType() && LinkFromSrc) {
524 GlobalVariable *NewDGV =
525 new GlobalVariable(SGV->getType()->getElementType(),
526 DGV->isConstant(), DGV->getLinkage());
527 NewDGV->setAlignment(DGV->getAlignment());
528 NewDGV->setSection(DGV->getSection());
529 NewDGV->setVisibility(DGV->getVisibility());
530 Dest->getGlobalList().insert(DGV, NewDGV);
531 DGV->replaceAllUsesWith(
532 ConstantExpr::getBitCast(NewDGV, DGV->getType()));
533 DGV->eraseFromParent();
534 NewDGV->setName(SGV->getName());
538 DGV->setLinkage(NewLinkage);
541 // Inherit const as appropriate
542 DGV->setConstant(SGV->isConstant());
543 DGV->setInitializer(0);
545 if (SGV->isConstant() && !DGV->isConstant()) {
546 if (DGV->isDeclaration())
547 DGV->setConstant(true);
549 SGV->setLinkage(GlobalValue::ExternalLinkage);
550 SGV->setInitializer(0);
554 std::make_pair(SGV, ConstantExpr::getBitCast(DGV, SGV->getType())));
561 // LinkGlobalInits - Update the initializers in the Dest module now that all
562 // globals that may be referenced are in Dest.
563 static bool LinkGlobalInits(Module *Dest, const Module *Src,
564 std::map<const Value*, Value*> &ValueMap,
567 // Loop over all of the globals in the src module, mapping them over as we go
568 for (Module::const_global_iterator I = Src->global_begin(),
569 E = Src->global_end(); I != E; ++I) {
570 const GlobalVariable *SGV = I;
572 if (SGV->hasInitializer()) { // Only process initialized GV's
573 // Figure out what the initializer looks like in the dest module...
575 cast<Constant>(RemapOperand(SGV->getInitializer(), ValueMap));
577 GlobalVariable *DGV = cast<GlobalVariable>(ValueMap[SGV]);
578 if (DGV->hasInitializer()) {
579 if (SGV->hasExternalLinkage()) {
580 if (DGV->getInitializer() != SInit)
581 return Error(Err, "Global Variable Collision on '" +
582 ToStr(SGV->getType(), Src) +"':%"+SGV->getName()+
583 " - Global variables have different initializers");
584 } else if (DGV->hasLinkOnceLinkage() || DGV->hasWeakLinkage()) {
585 // Nothing is required, mapped values will take the new global
587 } else if (SGV->hasLinkOnceLinkage() || SGV->hasWeakLinkage()) {
588 // Nothing is required, mapped values will take the new global
590 } else if (DGV->hasAppendingLinkage()) {
591 assert(0 && "Appending linkage unimplemented!");
593 assert(0 && "Unknown linkage!");
596 // Copy the initializer over now...
597 DGV->setInitializer(SInit);
604 // LinkFunctionProtos - Link the functions together between the two modules,
605 // without doing function bodies... this just adds external function prototypes
606 // to the Dest function...
608 static bool LinkFunctionProtos(Module *Dest, const Module *Src,
609 std::map<const Value*, Value*> &ValueMap,
610 std::map<std::string,
611 GlobalValue*> &GlobalsByName,
613 TypeSymbolTable *TST = &Dest->getTypeSymbolTable();
615 // Loop over all of the functions in the src module, mapping them over
616 for (Module::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) {
617 const Function *SF = I; // SrcFunction
619 if (SF->hasName() && !SF->hasInternalLinkage()) {
620 // Check to see if may have to link the function.
621 if (!(DF = Dest->getFunction(SF->getName(), SF->getFunctionType()))) {
622 std::map<std::string, GlobalValue*>::iterator EF =
623 GlobalsByName.find(SF->getName());
624 if (EF != GlobalsByName.end())
625 DF = dyn_cast<Function>(EF->second);
626 if (DF && RecursiveResolveTypes(SF->getType(), DF->getType(), TST, ""))
627 DF = 0; // FIXME: gross.
631 if (!DF || SF->hasInternalLinkage() || DF->hasInternalLinkage()) {
632 // Function does not already exist, simply insert an function signature
633 // identical to SF into the dest module...
634 Function *NewDF = new Function(SF->getFunctionType(), SF->getLinkage(),
635 SF->getName(), Dest);
636 NewDF->setCallingConv(SF->getCallingConv());
638 // If the LLVM runtime renamed the function, but it is an externally
639 // visible symbol, DF must be an existing function with internal linkage.
641 if (NewDF->getName() != SF->getName() && !NewDF->hasInternalLinkage())
642 ForceRenaming(NewDF, SF->getName());
644 // ... and remember this mapping...
645 ValueMap.insert(std::make_pair(SF, NewDF));
646 } else if (SF->isDeclaration()) {
647 // If SF is external or if both SF & DF are external.. Just link the
648 // external functions, we aren't adding anything.
649 if (SF->hasDLLImportLinkage()) {
650 if (DF->isDeclaration()) {
651 ValueMap.insert(std::make_pair(SF, DF));
652 DF->setLinkage(SF->getLinkage());
655 ValueMap.insert(std::make_pair(SF, DF));
657 } else if (DF->isDeclaration() && !DF->hasDLLImportLinkage()) {
658 // If DF is external but SF is not...
659 // Link the external functions, update linkage qualifiers
660 ValueMap.insert(std::make_pair(SF, DF));
661 DF->setLinkage(SF->getLinkage());
662 } else if (SF->hasWeakLinkage() || SF->hasLinkOnceLinkage()) {
663 // At this point we know that DF has LinkOnce, Weak, or External* linkage.
664 ValueMap.insert(std::make_pair(SF, DF));
666 // Linkonce+Weak = Weak
667 // *+External Weak = *
668 if ((DF->hasLinkOnceLinkage() && SF->hasWeakLinkage()) ||
669 DF->hasExternalWeakLinkage())
670 DF->setLinkage(SF->getLinkage());
673 } else if (DF->hasWeakLinkage() || DF->hasLinkOnceLinkage()) {
674 // At this point we know that SF has LinkOnce or External* linkage.
675 ValueMap.insert(std::make_pair(SF, DF));
676 if (!SF->hasLinkOnceLinkage() && !SF->hasExternalWeakLinkage())
677 // Don't inherit linkonce & external weak linkage
678 DF->setLinkage(SF->getLinkage());
679 } else if (SF->getLinkage() != DF->getLinkage()) {
680 return Error(Err, "Functions named '" + SF->getName() +
681 "' have different linkage specifiers!");
682 } else if (SF->hasExternalLinkage()) {
683 // The function is defined in both modules!!
684 return Error(Err, "Function '" +
685 ToStr(SF->getFunctionType(), Src) + "':\"" +
686 SF->getName() + "\" - Function is already defined!");
688 assert(0 && "Unknown linkage configuration found!");
694 // LinkFunctionBody - Copy the source function over into the dest function and
695 // fix up references to values. At this point we know that Dest is an external
696 // function, and that Src is not.
697 static bool LinkFunctionBody(Function *Dest, Function *Src,
698 std::map<const Value*, Value*> &GlobalMap,
700 assert(Src && Dest && Dest->isDeclaration() && !Src->isDeclaration());
702 // Go through and convert function arguments over, remembering the mapping.
703 Function::arg_iterator DI = Dest->arg_begin();
704 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end();
706 DI->setName(I->getName()); // Copy the name information over...
708 // Add a mapping to our local map
709 GlobalMap.insert(std::make_pair(I, DI));
712 // Splice the body of the source function into the dest function.
713 Dest->getBasicBlockList().splice(Dest->end(), Src->getBasicBlockList());
715 // At this point, all of the instructions and values of the function are now
716 // copied over. The only problem is that they are still referencing values in
717 // the Source function as operands. Loop through all of the operands of the
718 // functions and patch them up to point to the local versions...
720 for (Function::iterator BB = Dest->begin(), BE = Dest->end(); BB != BE; ++BB)
721 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
722 for (Instruction::op_iterator OI = I->op_begin(), OE = I->op_end();
724 if (!isa<Instruction>(*OI) && !isa<BasicBlock>(*OI))
725 *OI = RemapOperand(*OI, GlobalMap);
727 // There is no need to map the arguments anymore.
728 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end();
736 // LinkFunctionBodies - Link in the function bodies that are defined in the
737 // source module into the DestModule. This consists basically of copying the
738 // function over and fixing up references to values.
739 static bool LinkFunctionBodies(Module *Dest, Module *Src,
740 std::map<const Value*, Value*> &ValueMap,
743 // Loop over all of the functions in the src module, mapping them over as we
745 for (Module::iterator SF = Src->begin(), E = Src->end(); SF != E; ++SF) {
746 if (!SF->isDeclaration()) { // No body if function is external
747 Function *DF = cast<Function>(ValueMap[SF]); // Destination function
749 // DF not external SF external?
750 if (DF->isDeclaration()) {
751 // Only provide the function body if there isn't one already.
752 if (LinkFunctionBody(DF, SF, ValueMap, Err))
760 // LinkAppendingVars - If there were any appending global variables, link them
761 // together now. Return true on error.
762 static bool LinkAppendingVars(Module *M,
763 std::multimap<std::string, GlobalVariable *> &AppendingVars,
764 std::string *ErrorMsg) {
765 if (AppendingVars.empty()) return false; // Nothing to do.
767 // Loop over the multimap of appending vars, processing any variables with the
768 // same name, forming a new appending global variable with both of the
769 // initializers merged together, then rewrite references to the old variables
771 std::vector<Constant*> Inits;
772 while (AppendingVars.size() > 1) {
773 // Get the first two elements in the map...
774 std::multimap<std::string,
775 GlobalVariable*>::iterator Second = AppendingVars.begin(), First=Second++;
777 // If the first two elements are for different names, there is no pair...
778 // Otherwise there is a pair, so link them together...
779 if (First->first == Second->first) {
780 GlobalVariable *G1 = First->second, *G2 = Second->second;
781 const ArrayType *T1 = cast<ArrayType>(G1->getType()->getElementType());
782 const ArrayType *T2 = cast<ArrayType>(G2->getType()->getElementType());
784 // Check to see that they two arrays agree on type...
785 if (T1->getElementType() != T2->getElementType())
786 return Error(ErrorMsg,
787 "Appending variables with different element types need to be linked!");
788 if (G1->isConstant() != G2->isConstant())
789 return Error(ErrorMsg,
790 "Appending variables linked with different const'ness!");
792 unsigned NewSize = T1->getNumElements() + T2->getNumElements();
793 ArrayType *NewType = ArrayType::get(T1->getElementType(), NewSize);
795 G1->setName(""); // Clear G1's name in case of a conflict!
797 // Create the new global variable...
799 new GlobalVariable(NewType, G1->isConstant(), G1->getLinkage(),
800 /*init*/0, First->first, M);
802 // Merge the initializer...
803 Inits.reserve(NewSize);
804 if (ConstantArray *I = dyn_cast<ConstantArray>(G1->getInitializer())) {
805 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i)
806 Inits.push_back(I->getOperand(i));
808 assert(isa<ConstantAggregateZero>(G1->getInitializer()));
809 Constant *CV = Constant::getNullValue(T1->getElementType());
810 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i)
813 if (ConstantArray *I = dyn_cast<ConstantArray>(G2->getInitializer())) {
814 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i)
815 Inits.push_back(I->getOperand(i));
817 assert(isa<ConstantAggregateZero>(G2->getInitializer()));
818 Constant *CV = Constant::getNullValue(T2->getElementType());
819 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i)
822 NG->setInitializer(ConstantArray::get(NewType, Inits));
825 // Replace any uses of the two global variables with uses of the new
828 // FIXME: This should rewrite simple/straight-forward uses such as
829 // getelementptr instructions to not use the Cast!
830 G1->replaceAllUsesWith(ConstantExpr::getBitCast(NG, G1->getType()));
831 G2->replaceAllUsesWith(ConstantExpr::getBitCast(NG, G2->getType()));
833 // Remove the two globals from the module now...
834 M->getGlobalList().erase(G1);
835 M->getGlobalList().erase(G2);
837 // Put the new global into the AppendingVars map so that we can handle
838 // linking of more than two vars...
841 AppendingVars.erase(First);
848 // LinkModules - This function links two modules together, with the resulting
849 // left module modified to be the composite of the two input modules. If an
850 // error occurs, true is returned and ErrorMsg (if not null) is set to indicate
851 // the problem. Upon failure, the Dest module could be in a modified state, and
852 // shouldn't be relied on to be consistent.
854 Linker::LinkModules(Module *Dest, Module *Src, std::string *ErrorMsg) {
855 assert(Dest != 0 && "Invalid Destination module");
856 assert(Src != 0 && "Invalid Source Module");
858 if (Dest->getDataLayout().empty()) {
859 if (!Src->getDataLayout().empty()) {
860 Dest->setDataLayout(Src->getDataLayout());
862 std::string DataLayout;
864 if (Dest->getEndianness() == Module::AnyEndianness)
865 if (Src->getEndianness() == Module::BigEndian)
866 DataLayout.append("E");
867 else if (Src->getEndianness() == Module::LittleEndian)
868 DataLayout.append("e");
869 if (Dest->getPointerSize() == Module::AnyPointerSize)
870 if (Src->getPointerSize() == Module::Pointer64)
871 DataLayout.append(DataLayout.length() == 0 ? "p:64:64" : "-p:64:64");
872 else if (Src->getPointerSize() == Module::Pointer32)
873 DataLayout.append(DataLayout.length() == 0 ? "p:32:32" : "-p:32:32");
874 Dest->setDataLayout(DataLayout);
878 // COpy the target triple from the source to dest if the dest's is empty
879 if (Dest->getTargetTriple().empty() && !Src->getTargetTriple().empty())
880 Dest->setTargetTriple(Src->getTargetTriple());
882 if (!Src->getDataLayout().empty() && !Dest->getDataLayout().empty() &&
883 Src->getDataLayout() != Dest->getDataLayout())
884 cerr << "WARNING: Linking two modules of different data layouts!\n";
885 if (!Src->getTargetTriple().empty() &&
886 Dest->getTargetTriple() != Src->getTargetTriple())
887 cerr << "WARNING: Linking two modules of different target triples!\n";
889 // Append the module inline asm string
890 if (!Src->getModuleInlineAsm().empty()) {
891 if (Dest->getModuleInlineAsm().empty())
892 Dest->setModuleInlineAsm(Src->getModuleInlineAsm());
894 Dest->setModuleInlineAsm(Dest->getModuleInlineAsm()+"\n"+
895 Src->getModuleInlineAsm());
898 // Update the destination module's dependent libraries list with the libraries
899 // from the source module. There's no opportunity for duplicates here as the
900 // Module ensures that duplicate insertions are discarded.
901 Module::lib_iterator SI = Src->lib_begin();
902 Module::lib_iterator SE = Src->lib_end();
904 Dest->addLibrary(*SI);
908 // LinkTypes - Go through the symbol table of the Src module and see if any
909 // types are named in the src module that are not named in the Dst module.
910 // Make sure there are no type name conflicts.
911 if (LinkTypes(Dest, Src, ErrorMsg))
914 // ValueMap - Mapping of values from what they used to be in Src, to what they
916 std::map<const Value*, Value*> ValueMap;
918 // AppendingVars - Keep track of global variables in the destination module
919 // with appending linkage. After the module is linked together, they are
920 // appended and the module is rewritten.
921 std::multimap<std::string, GlobalVariable *> AppendingVars;
923 // GlobalsByName - The LLVM SymbolTable class fights our best efforts at
924 // linking by separating globals by type. Until PR411 is fixed, we replicate
925 // it's functionality here.
926 std::map<std::string, GlobalValue*> GlobalsByName;
928 for (Module::global_iterator I = Dest->global_begin(), E = Dest->global_end();
930 // Add all of the appending globals already in the Dest module to
932 if (I->hasAppendingLinkage())
933 AppendingVars.insert(std::make_pair(I->getName(), I));
935 // Keep track of all globals by name.
936 if (!I->hasInternalLinkage() && I->hasName())
937 GlobalsByName[I->getName()] = I;
940 // Keep track of all globals by name.
941 for (Module::iterator I = Dest->begin(), E = Dest->end(); I != E; ++I)
942 if (!I->hasInternalLinkage() && I->hasName())
943 GlobalsByName[I->getName()] = I;
945 // Insert all of the globals in src into the Dest module... without linking
946 // initializers (which could refer to functions not yet mapped over).
947 if (LinkGlobals(Dest, Src, ValueMap, AppendingVars, GlobalsByName, ErrorMsg))
950 // Link the functions together between the two modules, without doing function
951 // bodies... this just adds external function prototypes to the Dest
952 // function... We do this so that when we begin processing function bodies,
953 // all of the global values that may be referenced are available in our
955 if (LinkFunctionProtos(Dest, Src, ValueMap, GlobalsByName, ErrorMsg))
958 // Update the initializers in the Dest module now that all globals that may
959 // be referenced are in Dest.
960 if (LinkGlobalInits(Dest, Src, ValueMap, ErrorMsg)) return true;
962 // Link in the function bodies that are defined in the source module into the
963 // DestModule. This consists basically of copying the function over and
964 // fixing up references to values.
965 if (LinkFunctionBodies(Dest, Src, ValueMap, ErrorMsg)) return true;
967 // If there were any appending global variables, link them together now.
968 if (LinkAppendingVars(Dest, AppendingVars, ErrorMsg)) return true;
970 // If the source library's module id is in the dependent library list of the
971 // destination library, remove it since that module is now linked in.
973 modId.set(Src->getModuleIdentifier());
974 if (!modId.isEmpty())
975 Dest->removeLibrary(modId.getBasename());