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/ValueSymbolTable.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 references from one module to another.
273 // This is somewhat sophisticated in that it can automatically handle constants
274 // correctly as well.
275 static Value *RemapOperand(const Value *In,
276 std::map<const Value*, Value*> &ValueMap) {
277 std::map<const Value*,Value*>::const_iterator I = ValueMap.find(In);
278 if (I != ValueMap.end()) return I->second;
280 // Check to see if it's a constant that we are interested in transforming.
282 if (const Constant *CPV = dyn_cast<Constant>(In)) {
283 if ((!isa<DerivedType>(CPV->getType()) && !isa<ConstantExpr>(CPV)) ||
284 isa<ConstantInt>(CPV) || isa<ConstantAggregateZero>(CPV))
285 return const_cast<Constant*>(CPV); // Simple constants stay identical.
287 if (const ConstantArray *CPA = dyn_cast<ConstantArray>(CPV)) {
288 std::vector<Constant*> Operands(CPA->getNumOperands());
289 for (unsigned i = 0, e = CPA->getNumOperands(); i != e; ++i)
290 Operands[i] =cast<Constant>(RemapOperand(CPA->getOperand(i), ValueMap));
291 Result = ConstantArray::get(cast<ArrayType>(CPA->getType()), Operands);
292 } else if (const ConstantStruct *CPS = dyn_cast<ConstantStruct>(CPV)) {
293 std::vector<Constant*> Operands(CPS->getNumOperands());
294 for (unsigned i = 0, e = CPS->getNumOperands(); i != e; ++i)
295 Operands[i] =cast<Constant>(RemapOperand(CPS->getOperand(i), ValueMap));
296 Result = ConstantStruct::get(cast<StructType>(CPS->getType()), Operands);
297 } else if (isa<ConstantPointerNull>(CPV) || isa<UndefValue>(CPV)) {
298 Result = const_cast<Constant*>(CPV);
299 } else if (const ConstantPacked *CP = dyn_cast<ConstantPacked>(CPV)) {
300 std::vector<Constant*> Operands(CP->getNumOperands());
301 for (unsigned i = 0, e = CP->getNumOperands(); i != e; ++i)
302 Operands[i] = cast<Constant>(RemapOperand(CP->getOperand(i), ValueMap));
303 Result = ConstantPacked::get(Operands);
304 } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CPV)) {
305 std::vector<Constant*> Ops;
306 for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i)
307 Ops.push_back(cast<Constant>(RemapOperand(CE->getOperand(i),ValueMap)));
308 Result = CE->getWithOperands(Ops);
309 } else if (isa<Function>(CPV)) {
310 Result = const_cast<Constant*>(CPV);// Functions map to themselves.
311 } else if (isa<GlobalValue>(CPV)) {
312 assert(0 && "Unmapped global?");
314 assert(0 && "Unknown type of derived type constant value!");
316 } else if (isa<InlineAsm>(In)) {
317 Result = const_cast<Value*>(In);
320 // Cache the mapping in our local map structure
322 ValueMap.insert(std::make_pair(In, Result));
326 cerr << "LinkModules ValueMap: \n";
329 cerr << "Couldn't remap value: " << (void*)In << " " << *In << "\n";
330 assert(0 && "Couldn't remap value!");
334 /// ForceRenaming - The LLVM ValueSymbolTable class autorenames globals that
335 /// conflict in the symbol table. This is good for all clients except for us.
336 /// Go through the trouble to force this back.
337 static void ForceRenaming(GlobalValue *GV, const std::string &Name) {
338 assert(GV->getName() != Name && "Can't force rename to self");
339 ValueSymbolTable &ST = GV->getParent()->getValueSymbolTable();
341 // If there is a conflict, rename the conflict.
342 GlobalValue *ConflictGV = cast<GlobalValue>(ST.lookup(Name));
344 ConflictGV->setName(""); // Eliminate the conflict
345 GV->setName(Name); // Force the name back
346 ConflictGV->setName(Name); // This will cause ConflictGV to get renamed
347 assert(GV->getName() == Name && ConflictGV->getName() != Name &&
348 "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, DLL*
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,
435 // We will need a module level symbol table if the src module has a module
436 // level symbol table...
437 TypeSymbolTable *TyST = &Dest->getTypeSymbolTable();
439 // Loop over all of the globals in the src module, mapping them over as we go
440 for (Module::global_iterator I = Src->global_begin(), E = Src->global_end();
442 GlobalVariable *SGV = I;
443 GlobalVariable *DGV = 0;
444 // Check to see if may have to link the global.
445 if (SGV->hasName() && !SGV->hasInternalLinkage()) {
446 // See if the gvar exists already in the destination module
447 if ((DGV = Dest->getGlobalVariable(SGV->getName())))
448 // If types don't agree due to opaque types, try to resolve them.
449 RecursiveResolveTypes(SGV->getType(), DGV->getType(), TyST, "");
452 if (DGV && DGV->hasInternalLinkage())
455 assert(SGV->hasInitializer() || SGV->hasExternalWeakLinkage() ||
456 SGV->hasExternalLinkage() || SGV->hasDLLImportLinkage() &&
457 "Global must either be external or have an initializer!");
459 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage;
460 bool LinkFromSrc = false;
461 if (GetLinkageResult(DGV, SGV, NewLinkage, LinkFromSrc, Err))
465 // No linking to be performed, simply create an identical version of the
466 // symbol over in the dest module... the initializer will be filled in
467 // later by LinkGlobalInits...
468 GlobalVariable *NewDGV =
469 new GlobalVariable(SGV->getType()->getElementType(),
470 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
471 SGV->getName(), Dest);
472 // Propagate alignment, section and visibility
473 NewDGV->setAlignment(SGV->getAlignment());
474 NewDGV->setSection(SGV->getSection());
475 NewDGV->setVisibility(SGV->getVisibility());
477 // If the LLVM runtime renamed the global, but it is an externally visible
478 // symbol, DGV must be an existing global with internal linkage. Rename
480 if (NewDGV->getName() != SGV->getName() && !NewDGV->hasInternalLinkage())
481 ForceRenaming(NewDGV, SGV->getName());
483 // Make sure to remember this mapping...
484 ValueMap.insert(std::make_pair(SGV, NewDGV));
485 if (SGV->hasAppendingLinkage())
486 // Keep track that this is an appending variable...
487 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV));
488 } else if (DGV->hasAppendingLinkage()) {
489 // No linking is performed yet. Just insert a new copy of the global, and
490 // keep track of the fact that it is an appending variable in the
491 // AppendingVars map. The name is cleared out so that no linkage is
493 GlobalVariable *NewDGV =
494 new GlobalVariable(SGV->getType()->getElementType(),
495 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
498 // Propagate alignment, section and visibility
499 NewDGV->setAlignment(std::max(DGV->getAlignment(), SGV->getAlignment()));
500 NewDGV->setSection(SGV->getSection());
501 NewDGV->setVisibility(SGV->getVisibility());
503 // Make sure to remember this mapping...
504 ValueMap.insert(std::make_pair(SGV, NewDGV));
506 // Keep track that this is an appending variable...
507 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV));
509 // Propagate alignment, section and visibility info.
510 DGV->setAlignment(std::max(DGV->getAlignment(), SGV->getAlignment()));
511 DGV->setSection(SGV->getSection());
512 DGV->setVisibility(SGV->getVisibility());
514 // Otherwise, perform the mapping as instructed by GetLinkageResult. If
515 // the types don't match, and if we are to link from the source, nuke DGV
516 // and create a new one of the appropriate type.
517 if (SGV->getType() != DGV->getType() && LinkFromSrc) {
518 GlobalVariable *NewDGV =
519 new GlobalVariable(SGV->getType()->getElementType(),
520 DGV->isConstant(), DGV->getLinkage());
521 NewDGV->setAlignment(DGV->getAlignment());
522 NewDGV->setVisibility(DGV->getVisibility());
523 NewDGV->setSection(DGV->getSection());
524 Dest->getGlobalList().insert(DGV, NewDGV);
525 DGV->replaceAllUsesWith(
526 ConstantExpr::getBitCast(NewDGV, DGV->getType()));
527 DGV->eraseFromParent();
528 NewDGV->setName(SGV->getName());
532 DGV->setLinkage(NewLinkage);
535 // Inherit const as appropriate
536 DGV->setConstant(SGV->isConstant());
537 DGV->setInitializer(0);
538 DGV->setVisibility(SGV->getVisibility());
540 if (SGV->isConstant() && !DGV->isConstant()) {
541 if (DGV->isDeclaration())
542 DGV->setConstant(true);
544 SGV->setLinkage(GlobalValue::ExternalLinkage);
545 SGV->setInitializer(0);
549 std::make_pair(SGV, ConstantExpr::getBitCast(DGV, SGV->getType())));
556 // LinkGlobalInits - Update the initializers in the Dest module now that all
557 // globals that may be referenced are in Dest.
558 static bool LinkGlobalInits(Module *Dest, const Module *Src,
559 std::map<const Value*, Value*> &ValueMap,
562 // Loop over all of the globals in the src module, mapping them over as we go
563 for (Module::const_global_iterator I = Src->global_begin(),
564 E = Src->global_end(); I != E; ++I) {
565 const GlobalVariable *SGV = I;
567 if (SGV->hasInitializer()) { // Only process initialized GV's
568 // Figure out what the initializer looks like in the dest module...
570 cast<Constant>(RemapOperand(SGV->getInitializer(), ValueMap));
572 GlobalVariable *DGV = cast<GlobalVariable>(ValueMap[SGV]);
573 if (DGV->hasInitializer()) {
574 if (SGV->hasExternalLinkage()) {
575 if (DGV->getInitializer() != SInit)
576 return Error(Err, "Global Variable Collision on '" +
577 ToStr(SGV->getType(), Src) +"':%"+SGV->getName()+
578 " - Global variables have different initializers");
579 } else if (DGV->hasLinkOnceLinkage() || DGV->hasWeakLinkage()) {
580 // Nothing is required, mapped values will take the new global
582 } else if (SGV->hasLinkOnceLinkage() || SGV->hasWeakLinkage()) {
583 // Nothing is required, mapped values will take the new global
585 } else if (DGV->hasAppendingLinkage()) {
586 assert(0 && "Appending linkage unimplemented!");
588 assert(0 && "Unknown linkage!");
591 // Copy the initializer over now...
592 DGV->setInitializer(SInit);
599 // LinkFunctionProtos - Link the functions together between the two modules,
600 // without doing function bodies... this just adds external function prototypes
601 // to the Dest function...
603 static bool LinkFunctionProtos(Module *Dest, const Module *Src,
604 std::map<const Value*, Value*> &ValueMap,
606 TypeSymbolTable *TyST = &Dest->getTypeSymbolTable();
608 // Loop over all of the functions in the src module, mapping them over as we
610 for (Module::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) {
611 const Function *SF = I; // SrcFunction
613 if (SF->hasName() && !SF->hasInternalLinkage())
614 // See if there is a function with the same name in the destination
615 if ((DF = Dest->getFunction(SF->getName()))) {
616 // Resolve Opaque types, etc.
617 RecursiveResolveTypes(SF->getType(), DF->getType(), TyST, "");
620 // If we have two globals of the same name but different type
621 if (DF && DF->getType() != SF->getType()) {
622 if (DF->isDeclaration() && !SF->isDeclaration()) {
623 // We have a definition of the same name but different type in the
624 // source module. Copy the prototype to the destination and replace
625 // uses of the destination's prototype with the new prototype.
626 Function *NewDF = new Function(SF->getFunctionType(), SF->getLinkage(),
627 SF->getName(), Dest);
628 NewDF->setCallingConv(SF->getCallingConv());
629 NewDF->setVisibility(SF->getVisibility());
631 // If the symbol table renamed the function, but it is an externally
632 // visible symbol, DF must be an existing function with internal
633 // linkage. Rename it.
634 if (NewDF->getName() != SF->getName() && !NewDF->hasInternalLinkage())
635 ForceRenaming(NewDF, SF->getName());
637 // Any uses of DF need to change to NewDF, with cast
638 DF->replaceAllUsesWith(ConstantExpr::getBitCast(NewDF, DF->getType()));
639 DF->eraseFromParent();
641 // Remember this mapping so uses in the source module get remapped
642 // later by RemapOperand.
643 ValueMap.insert(std::make_pair(SF, NewDF));
644 } else if (SF->isDeclaration()) {
645 // The source is just a prototype, simply set up a mapping from the
646 // source to the destination function. We can't do the replacement
647 // now so its deferred to LinkFunctionBodies.
648 ValueMap.insert(std::make_pair(SF, DF));
650 // We have two definitions of different function types of the same
651 // name. This is a multiple definition error.
652 return Error(Err, "Function '" + DF->getName() + "' defined as both '" +
653 ToStr(SF->getFunctionType(), Src) + "' and '" +
654 ToStr(DF->getFunctionType(), Dest) + "'");
656 } else if (!DF || SF->hasInternalLinkage() || DF->hasInternalLinkage()) {
657 // Function does not already exist, simply insert an function signature
658 // identical to SF into the dest module...
659 Function *NewDF = new Function(SF->getFunctionType(), SF->getLinkage(),
660 SF->getName(), Dest);
661 NewDF->setCallingConv(SF->getCallingConv());
662 NewDF->setVisibility(SF->getVisibility());
664 // If the LLVM runtime renamed the function, but it is an externally
665 // visible symbol, DF must be an existing function with internal linkage.
667 if (NewDF->getName() != SF->getName() && !NewDF->hasInternalLinkage())
668 ForceRenaming(NewDF, SF->getName());
670 // ... and remember this mapping...
671 ValueMap.insert(std::make_pair(SF, NewDF));
672 } else if (SF->isDeclaration()) {
673 // If SF is external or if both SF & DF are external.. Just link the
674 // external functions, we aren't adding anything.
675 if (SF->hasDLLImportLinkage()) {
676 if (DF->isDeclaration()) {
677 ValueMap.insert(std::make_pair(SF, DF));
678 DF->setLinkage(SF->getLinkage());
681 ValueMap.insert(std::make_pair(SF, DF));
683 } else if (DF->isDeclaration() && !DF->hasDLLImportLinkage()) {
684 // If DF is external but SF is not...
685 // Link the external functions, update linkage qualifiers
686 ValueMap.insert(std::make_pair(SF, DF));
687 DF->setLinkage(SF->getLinkage());
688 } else if (SF->hasWeakLinkage() || SF->hasLinkOnceLinkage()) {
689 // At this point we know that DF has LinkOnce, Weak, or External* linkage.
690 ValueMap.insert(std::make_pair(SF, DF));
692 // Linkonce+Weak = Weak
693 // *+External Weak = *
694 if ((DF->hasLinkOnceLinkage() && SF->hasWeakLinkage()) ||
695 DF->hasExternalWeakLinkage())
696 DF->setLinkage(SF->getLinkage());
697 } else if (DF->hasWeakLinkage() || DF->hasLinkOnceLinkage()) {
698 // At this point we know that SF has LinkOnce or External* linkage.
699 ValueMap.insert(std::make_pair(SF, DF));
700 if (!SF->hasLinkOnceLinkage() && !SF->hasExternalWeakLinkage())
701 // Don't inherit linkonce & external weak linkage
702 DF->setLinkage(SF->getLinkage());
703 } else if (SF->getLinkage() != DF->getLinkage()) {
704 return Error(Err, "Functions named '" + SF->getName() +
705 "' have different linkage specifiers!");
706 } else if (SF->hasExternalLinkage()) {
707 // The function is defined in both modules!!
708 return Error(Err, "Function '" +
709 ToStr(SF->getFunctionType(), Src) + "':\"" +
710 SF->getName() + "\" - Function is already defined!");
712 assert(0 && "Unknown linkage configuration found!");
718 // LinkFunctionBody - Copy the source function over into the dest function and
719 // fix up references to values. At this point we know that Dest is an external
720 // function, and that Src is not.
721 static bool LinkFunctionBody(Function *Dest, Function *Src,
722 std::map<const Value*, Value*> &GlobalMap,
724 assert(Src && Dest && Dest->isDeclaration() && !Src->isDeclaration());
726 // Go through and convert function arguments over, remembering the mapping.
727 Function::arg_iterator DI = Dest->arg_begin();
728 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end();
730 DI->setName(I->getName()); // Copy the name information over...
732 // Add a mapping to our local map
733 GlobalMap.insert(std::make_pair(I, DI));
736 // Splice the body of the source function into the dest function.
737 Dest->getBasicBlockList().splice(Dest->end(), Src->getBasicBlockList());
739 // At this point, all of the instructions and values of the function are now
740 // copied over. The only problem is that they are still referencing values in
741 // the Source function as operands. Loop through all of the operands of the
742 // functions and patch them up to point to the local versions...
744 for (Function::iterator BB = Dest->begin(), BE = Dest->end(); BB != BE; ++BB)
745 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
746 for (Instruction::op_iterator OI = I->op_begin(), OE = I->op_end();
748 if (!isa<Instruction>(*OI) && !isa<BasicBlock>(*OI))
749 *OI = RemapOperand(*OI, GlobalMap);
751 // There is no need to map the arguments anymore.
752 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end();
760 // LinkFunctionBodies - Link in the function bodies that are defined in the
761 // source module into the DestModule. This consists basically of copying the
762 // function over and fixing up references to values.
763 static bool LinkFunctionBodies(Module *Dest, Module *Src,
764 std::map<const Value*, Value*> &ValueMap,
767 // Loop over all of the functions in the src module, mapping them over
768 for (Module::iterator SF = Src->begin(), E = Src->end(); SF != E; ++SF) {
769 if (!SF->isDeclaration()) { // No body if function is external
770 Function *DF = cast<Function>(ValueMap[SF]); // Destination function
772 // DF not external SF external?
773 if (DF->isDeclaration())
774 // Only provide the function body if there isn't one already.
775 if (LinkFunctionBody(DF, SF, ValueMap, Err))
778 // The source function is a prototype. If there's a mapping for this,
779 // then replace all its uses with the mapped function, after cast. This
780 // occurs when two functions of the same name but different type
782 Function *DF = cast<Function>(ValueMap[SF]); // Destination function
784 SF->replaceAllUsesWith(ConstantExpr::getBitCast(DF, SF->getType()));
790 // LinkAppendingVars - If there were any appending global variables, link them
791 // together now. Return true on error.
792 static bool LinkAppendingVars(Module *M,
793 std::multimap<std::string, GlobalVariable *> &AppendingVars,
794 std::string *ErrorMsg) {
795 if (AppendingVars.empty()) return false; // Nothing to do.
797 // Loop over the multimap of appending vars, processing any variables with the
798 // same name, forming a new appending global variable with both of the
799 // initializers merged together, then rewrite references to the old variables
801 std::vector<Constant*> Inits;
802 while (AppendingVars.size() > 1) {
803 // Get the first two elements in the map...
804 std::multimap<std::string,
805 GlobalVariable*>::iterator Second = AppendingVars.begin(), First=Second++;
807 // If the first two elements are for different names, there is no pair...
808 // Otherwise there is a pair, so link them together...
809 if (First->first == Second->first) {
810 GlobalVariable *G1 = First->second, *G2 = Second->second;
811 const ArrayType *T1 = cast<ArrayType>(G1->getType()->getElementType());
812 const ArrayType *T2 = cast<ArrayType>(G2->getType()->getElementType());
814 // Check to see that they two arrays agree on type...
815 if (T1->getElementType() != T2->getElementType())
816 return Error(ErrorMsg,
817 "Appending variables with different element types need to be linked!");
818 if (G1->isConstant() != G2->isConstant())
819 return Error(ErrorMsg,
820 "Appending variables linked with different const'ness!");
822 unsigned NewSize = T1->getNumElements() + T2->getNumElements();
823 ArrayType *NewType = ArrayType::get(T1->getElementType(), NewSize);
825 G1->setName(""); // Clear G1's name in case of a conflict!
827 // Create the new global variable...
829 new GlobalVariable(NewType, G1->isConstant(), G1->getLinkage(),
830 /*init*/0, First->first, M);
832 // Merge the initializer...
833 Inits.reserve(NewSize);
834 if (ConstantArray *I = dyn_cast<ConstantArray>(G1->getInitializer())) {
835 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i)
836 Inits.push_back(I->getOperand(i));
838 assert(isa<ConstantAggregateZero>(G1->getInitializer()));
839 Constant *CV = Constant::getNullValue(T1->getElementType());
840 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i)
843 if (ConstantArray *I = dyn_cast<ConstantArray>(G2->getInitializer())) {
844 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i)
845 Inits.push_back(I->getOperand(i));
847 assert(isa<ConstantAggregateZero>(G2->getInitializer()));
848 Constant *CV = Constant::getNullValue(T2->getElementType());
849 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i)
852 NG->setInitializer(ConstantArray::get(NewType, Inits));
855 // Replace any uses of the two global variables with uses of the new
858 // FIXME: This should rewrite simple/straight-forward uses such as
859 // getelementptr instructions to not use the Cast!
860 G1->replaceAllUsesWith(ConstantExpr::getBitCast(NG, G1->getType()));
861 G2->replaceAllUsesWith(ConstantExpr::getBitCast(NG, G2->getType()));
863 // Remove the two globals from the module now...
864 M->getGlobalList().erase(G1);
865 M->getGlobalList().erase(G2);
867 // Put the new global into the AppendingVars map so that we can handle
868 // linking of more than two vars...
871 AppendingVars.erase(First);
878 // LinkModules - This function links two modules together, with the resulting
879 // left module modified to be the composite of the two input modules. If an
880 // error occurs, true is returned and ErrorMsg (if not null) is set to indicate
881 // the problem. Upon failure, the Dest module could be in a modified state, and
882 // shouldn't be relied on to be consistent.
884 Linker::LinkModules(Module *Dest, Module *Src, std::string *ErrorMsg) {
885 assert(Dest != 0 && "Invalid Destination module");
886 assert(Src != 0 && "Invalid Source Module");
888 if (Dest->getDataLayout().empty()) {
889 if (!Src->getDataLayout().empty()) {
890 Dest->setDataLayout(Src->getDataLayout());
892 std::string DataLayout;
894 if (Dest->getEndianness() == Module::AnyEndianness)
895 if (Src->getEndianness() == Module::BigEndian)
896 DataLayout.append("E");
897 else if (Src->getEndianness() == Module::LittleEndian)
898 DataLayout.append("e");
899 if (Dest->getPointerSize() == Module::AnyPointerSize)
900 if (Src->getPointerSize() == Module::Pointer64)
901 DataLayout.append(DataLayout.length() == 0 ? "p:64:64" : "-p:64:64");
902 else if (Src->getPointerSize() == Module::Pointer32)
903 DataLayout.append(DataLayout.length() == 0 ? "p:32:32" : "-p:32:32");
904 Dest->setDataLayout(DataLayout);
908 // Copy the target triple from the source to dest if the dest is empty
909 if (Dest->getTargetTriple().empty() && !Src->getTargetTriple().empty())
910 Dest->setTargetTriple(Src->getTargetTriple());
912 if (!Src->getDataLayout().empty() && !Dest->getDataLayout().empty() &&
913 Src->getDataLayout() != Dest->getDataLayout())
914 cerr << "WARNING: Linking two modules of different data layouts!\n";
915 if (!Src->getTargetTriple().empty() &&
916 Dest->getTargetTriple() != Src->getTargetTriple())
917 cerr << "WARNING: Linking two modules of different target triples!\n";
919 // Append the module inline asm string
920 if (!Src->getModuleInlineAsm().empty()) {
921 if (Dest->getModuleInlineAsm().empty())
922 Dest->setModuleInlineAsm(Src->getModuleInlineAsm());
924 Dest->setModuleInlineAsm(Dest->getModuleInlineAsm()+"\n"+
925 Src->getModuleInlineAsm());
928 // Update the destination module's dependent libraries list with the libraries
929 // from the source module. There's no opportunity for duplicates here as the
930 // Module ensures that duplicate insertions are discarded.
931 Module::lib_iterator SI = Src->lib_begin();
932 Module::lib_iterator SE = Src->lib_end();
934 Dest->addLibrary(*SI);
938 // LinkTypes - Go through the symbol table of the Src module and see if any
939 // types are named in the src module that are not named in the Dst module.
940 // Make sure there are no type name conflicts.
941 if (LinkTypes(Dest, Src, ErrorMsg))
944 // ValueMap - Mapping of values from what they used to be in Src, to what they
946 std::map<const Value*, Value*> ValueMap;
948 // AppendingVars - Keep track of global variables in the destination module
949 // with appending linkage. After the module is linked together, they are
950 // appended and the module is rewritten.
951 std::multimap<std::string, GlobalVariable *> AppendingVars;
953 for (Module::global_iterator I = Dest->global_begin(), E = Dest->global_end();
955 // Add all of the appending globals already in the Dest module to
957 if (I->hasAppendingLinkage())
958 AppendingVars.insert(std::make_pair(I->getName(), I));
961 // Insert all of the globals in src into the Dest module... without linking
962 // initializers (which could refer to functions not yet mapped over).
963 if (LinkGlobals(Dest, Src, ValueMap, AppendingVars, ErrorMsg))
966 // Link the functions together between the two modules, without doing function
967 // bodies... this just adds external function prototypes to the Dest
968 // function... We do this so that when we begin processing function bodies,
969 // all of the global values that may be referenced are available in our
971 if (LinkFunctionProtos(Dest, Src, ValueMap, ErrorMsg))
974 // Update the initializers in the Dest module now that all globals that may
975 // be referenced are in Dest.
976 if (LinkGlobalInits(Dest, Src, ValueMap, ErrorMsg)) return true;
978 // Link in the function bodies that are defined in the source module into the
979 // DestModule. This consists basically of copying the function over and
980 // fixing up references to values.
981 if (LinkFunctionBodies(Dest, Src, ValueMap, ErrorMsg)) return true;
983 // If there were any appending global variables, link them together now.
984 if (LinkAppendingVars(Dest, AppendingVars, ErrorMsg)) return true;
986 // If the source library's module id is in the dependent library list of the
987 // destination library, remove it since that module is now linked in.
989 modId.set(Src->getModuleIdentifier());
990 if (!modId.isEmpty())
991 Dest->removeLibrary(modId.getBasename());