1 //===- Linker.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/Support/Linker.h"
20 #include "llvm/Constants.h"
21 #include "llvm/DerivedTypes.h"
22 #include "llvm/Module.h"
23 #include "llvm/SymbolTable.h"
24 #include "llvm/Instructions.h"
25 #include "llvm/Assembly/Writer.h"
26 #include "llvm/System/Path.h"
31 // Error - Simple wrapper function to conditionally assign to E and return true.
32 // This just makes error return conditions a little bit simpler...
34 static inline bool Error(std::string *E, const std::string &Message) {
39 static std::string ToStr(const Type *Ty, const Module *M) {
40 std::ostringstream OS;
41 WriteTypeSymbolic(OS, Ty, M);
46 // Function: ResolveTypes()
49 // Attempt to link the two specified types together.
52 // DestTy - The type to which we wish to resolve.
53 // SrcTy - The original type which we want to resolve.
54 // Name - The name of the type.
57 // DestST - The symbol table in which the new type should be placed.
60 // true - There is an error and the types cannot yet be linked.
63 static bool ResolveTypes(const Type *DestTy, const Type *SrcTy,
64 SymbolTable *DestST, const std::string &Name) {
65 if (DestTy == SrcTy) return false; // If already equal, noop
67 // Does the type already exist in the module?
68 if (DestTy && !isa<OpaqueType>(DestTy)) { // Yup, the type already exists...
69 if (const OpaqueType *OT = dyn_cast<OpaqueType>(SrcTy)) {
70 const_cast<OpaqueType*>(OT)->refineAbstractTypeTo(DestTy);
72 return true; // Cannot link types... neither is opaque and not-equal
74 } else { // Type not in dest module. Add it now.
75 if (DestTy) // Type _is_ in module, just opaque...
76 const_cast<OpaqueType*>(cast<OpaqueType>(DestTy))
77 ->refineAbstractTypeTo(SrcTy);
78 else if (!Name.empty())
79 DestST->insert(Name, const_cast<Type*>(SrcTy));
84 static const FunctionType *getFT(const PATypeHolder &TH) {
85 return cast<FunctionType>(TH.get());
87 static const StructType *getST(const PATypeHolder &TH) {
88 return cast<StructType>(TH.get());
91 // RecursiveResolveTypes - This is just like ResolveTypes, except that it
92 // 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 SymbolTable *DestST, const std::string &Name,
98 std::vector<std::pair<PATypeHolder, PATypeHolder> > &Pointers) {
99 const Type *SrcTyT = SrcTy.get();
100 const Type *DestTyT = DestTy.get();
101 if (DestTyT == SrcTyT) return false; // If already equal, noop
103 // If we found our opaque type, resolve it now!
104 if (isa<OpaqueType>(DestTyT) || isa<OpaqueType>(SrcTyT))
105 return ResolveTypes(DestTyT, SrcTyT, DestST, Name);
107 // Two types cannot be resolved together if they are of different primitive
108 // type. For example, we cannot resolve an int to a float.
109 if (DestTyT->getTypeID() != SrcTyT->getTypeID()) return true;
111 // Otherwise, resolve the used type used by this derived type...
112 switch (DestTyT->getTypeID()) {
113 case Type::FunctionTyID: {
114 if (cast<FunctionType>(DestTyT)->isVarArg() !=
115 cast<FunctionType>(SrcTyT)->isVarArg() ||
116 cast<FunctionType>(DestTyT)->getNumContainedTypes() !=
117 cast<FunctionType>(SrcTyT)->getNumContainedTypes())
119 for (unsigned i = 0, e = getFT(DestTy)->getNumContainedTypes(); i != e; ++i)
120 if (RecursiveResolveTypesI(getFT(DestTy)->getContainedType(i),
121 getFT(SrcTy)->getContainedType(i), DestST, "",
126 case Type::StructTyID: {
127 if (getST(DestTy)->getNumContainedTypes() !=
128 getST(SrcTy)->getNumContainedTypes()) return 1;
129 for (unsigned i = 0, e = getST(DestTy)->getNumContainedTypes(); i != e; ++i)
130 if (RecursiveResolveTypesI(getST(DestTy)->getContainedType(i),
131 getST(SrcTy)->getContainedType(i), DestST, "",
136 case Type::ArrayTyID: {
137 const ArrayType *DAT = cast<ArrayType>(DestTy.get());
138 const ArrayType *SAT = cast<ArrayType>(SrcTy.get());
139 if (DAT->getNumElements() != SAT->getNumElements()) return true;
140 return RecursiveResolveTypesI(DAT->getElementType(), SAT->getElementType(),
141 DestST, "", Pointers);
143 case Type::PointerTyID: {
144 // If this is a pointer type, check to see if we have already seen it. If
145 // so, we are in a recursive branch. Cut off the search now. We cannot use
146 // an associative container for this search, because the type pointers (keys
147 // in the container) change whenever types get resolved...
149 for (unsigned i = 0, e = Pointers.size(); i != e; ++i)
150 if (Pointers[i].first == DestTy)
151 return Pointers[i].second != SrcTy;
153 // Otherwise, add the current pointers to the vector to stop recursion on
155 Pointers.push_back(std::make_pair(DestTyT, SrcTyT));
157 RecursiveResolveTypesI(cast<PointerType>(DestTy.get())->getElementType(),
158 cast<PointerType>(SrcTy.get())->getElementType(),
159 DestST, "", Pointers);
163 default: assert(0 && "Unexpected type!"); return true;
167 static bool RecursiveResolveTypes(const PATypeHolder &DestTy,
168 const PATypeHolder &SrcTy,
169 SymbolTable *DestST, const std::string &Name){
170 std::vector<std::pair<PATypeHolder, PATypeHolder> > PointerTypes;
171 return RecursiveResolveTypesI(DestTy, SrcTy, DestST, Name, PointerTypes);
175 // LinkTypes - Go through the symbol table of the Src module and see if any
176 // types are named in the src module that are not named in the Dst module.
177 // Make sure there are no type name conflicts.
179 static bool LinkTypes(Module *Dest, const Module *Src, std::string *Err) {
180 SymbolTable *DestST = &Dest->getSymbolTable();
181 const SymbolTable *SrcST = &Src->getSymbolTable();
183 // Look for a type plane for Type's...
184 SymbolTable::type_const_iterator TI = SrcST->type_begin();
185 SymbolTable::type_const_iterator TE = SrcST->type_end();
186 if (TI == TE) return false; // No named types, do nothing.
188 // Some types cannot be resolved immediately because they depend on other
189 // types being resolved to each other first. This contains a list of types we
190 // are waiting to recheck.
191 std::vector<std::string> DelayedTypesToResolve;
193 for ( ; TI != TE; ++TI ) {
194 const std::string &Name = TI->first;
195 const Type *RHS = TI->second;
197 // Check to see if this type name is already in the dest module...
198 Type *Entry = DestST->lookupType(Name);
200 if (ResolveTypes(Entry, RHS, DestST, Name)) {
201 // They look different, save the types 'till later to resolve.
202 DelayedTypesToResolve.push_back(Name);
206 // Iteratively resolve types while we can...
207 while (!DelayedTypesToResolve.empty()) {
208 // Loop over all of the types, attempting to resolve them if possible...
209 unsigned OldSize = DelayedTypesToResolve.size();
211 // Try direct resolution by name...
212 for (unsigned i = 0; i != DelayedTypesToResolve.size(); ++i) {
213 const std::string &Name = DelayedTypesToResolve[i];
214 Type *T1 = SrcST->lookupType(Name);
215 Type *T2 = DestST->lookupType(Name);
216 if (!ResolveTypes(T2, T1, DestST, Name)) {
217 // We are making progress!
218 DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i);
223 // Did we not eliminate any types?
224 if (DelayedTypesToResolve.size() == OldSize) {
225 // Attempt to resolve subelements of types. This allows us to merge these
226 // two types: { int* } and { opaque* }
227 for (unsigned i = 0, e = DelayedTypesToResolve.size(); i != e; ++i) {
228 const std::string &Name = DelayedTypesToResolve[i];
229 PATypeHolder T1(SrcST->lookupType(Name));
230 PATypeHolder T2(DestST->lookupType(Name));
232 if (!RecursiveResolveTypes(T2, T1, DestST, Name)) {
233 // We are making progress!
234 DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i);
236 // Go back to the main loop, perhaps we can resolve directly by name
242 // If we STILL cannot resolve the types, then there is something wrong.
243 // Report the warning and delete one of the names.
244 if (DelayedTypesToResolve.size() == OldSize) {
245 const std::string &Name = DelayedTypesToResolve.back();
247 const Type *T1 = SrcST->lookupType(Name);
248 const Type *T2 = DestST->lookupType(Name);
249 std::cerr << "WARNING: Type conflict between types named '" << Name
251 WriteTypeSymbolic(std::cerr, T1, Src);
252 std::cerr << "'.\n Dest='";
253 WriteTypeSymbolic(std::cerr, T2, Dest);
256 // Remove the symbol name from the destination.
257 DelayedTypesToResolve.pop_back();
266 static void PrintMap(const std::map<const Value*, Value*> &M) {
267 for (std::map<const Value*, Value*>::const_iterator I = M.begin(), E =M.end();
269 std::cerr << " Fr: " << (void*)I->first << " ";
271 std::cerr << " To: " << (void*)I->second << " ";
278 // RemapOperand - Use LocalMap and GlobalMap to convert references from one
279 // module to another. This is somewhat sophisticated in that it can
280 // automatically handle constant references correctly as well...
282 static Value *RemapOperand(const Value *In,
283 std::map<const Value*, Value*> &LocalMap,
284 std::map<const Value*, Value*> *GlobalMap) {
285 std::map<const Value*,Value*>::const_iterator I = LocalMap.find(In);
286 if (I != LocalMap.end()) return I->second;
289 I = GlobalMap->find(In);
290 if (I != GlobalMap->end()) return I->second;
293 // Check to see if it's a constant that we are interesting in transforming...
294 if (const Constant *CPV = dyn_cast<Constant>(In)) {
295 if ((!isa<DerivedType>(CPV->getType()) && !isa<ConstantExpr>(CPV)) ||
296 isa<ConstantAggregateZero>(CPV))
297 return const_cast<Constant*>(CPV); // Simple constants stay identical...
299 Constant *Result = 0;
301 if (const ConstantArray *CPA = dyn_cast<ConstantArray>(CPV)) {
302 std::vector<Constant*> Operands(CPA->getNumOperands());
303 for (unsigned i = 0, e = CPA->getNumOperands(); i != e; ++i)
305 cast<Constant>(RemapOperand(CPA->getOperand(i), LocalMap, GlobalMap));
306 Result = ConstantArray::get(cast<ArrayType>(CPA->getType()), Operands);
307 } else if (const ConstantStruct *CPS = dyn_cast<ConstantStruct>(CPV)) {
308 std::vector<Constant*> Operands(CPS->getNumOperands());
309 for (unsigned i = 0, e = CPS->getNumOperands(); i != e; ++i)
311 cast<Constant>(RemapOperand(CPS->getOperand(i), LocalMap, GlobalMap));
312 Result = ConstantStruct::get(cast<StructType>(CPS->getType()), Operands);
313 } else if (isa<ConstantPointerNull>(CPV)) {
314 Result = const_cast<Constant*>(CPV);
315 } else if (isa<GlobalValue>(CPV)) {
316 Result = cast<Constant>(RemapOperand(CPV, LocalMap, GlobalMap));
317 } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CPV)) {
318 if (CE->getOpcode() == Instruction::GetElementPtr) {
319 Value *Ptr = RemapOperand(CE->getOperand(0), LocalMap, GlobalMap);
320 std::vector<Constant*> Indices;
321 Indices.reserve(CE->getNumOperands()-1);
322 for (unsigned i = 1, e = CE->getNumOperands(); i != e; ++i)
323 Indices.push_back(cast<Constant>(RemapOperand(CE->getOperand(i),
324 LocalMap, GlobalMap)));
326 Result = ConstantExpr::getGetElementPtr(cast<Constant>(Ptr), Indices);
327 } else if (CE->getNumOperands() == 1) {
329 assert(CE->getOpcode() == Instruction::Cast);
330 Value *V = RemapOperand(CE->getOperand(0), LocalMap, GlobalMap);
331 Result = ConstantExpr::getCast(cast<Constant>(V), CE->getType());
332 } else if (CE->getNumOperands() == 3) {
333 // Select instruction
334 assert(CE->getOpcode() == Instruction::Select);
335 Value *V1 = RemapOperand(CE->getOperand(0), LocalMap, GlobalMap);
336 Value *V2 = RemapOperand(CE->getOperand(1), LocalMap, GlobalMap);
337 Value *V3 = RemapOperand(CE->getOperand(2), LocalMap, GlobalMap);
338 Result = ConstantExpr::getSelect(cast<Constant>(V1), cast<Constant>(V2),
340 } else if (CE->getNumOperands() == 2) {
341 // Binary operator...
342 Value *V1 = RemapOperand(CE->getOperand(0), LocalMap, GlobalMap);
343 Value *V2 = RemapOperand(CE->getOperand(1), LocalMap, GlobalMap);
345 Result = ConstantExpr::get(CE->getOpcode(), cast<Constant>(V1),
348 assert(0 && "Unknown constant expr type!");
352 assert(0 && "Unknown type of derived type constant value!");
355 // Cache the mapping in our local map structure...
357 GlobalMap->insert(std::make_pair(In, Result));
359 LocalMap.insert(std::make_pair(In, Result));
363 std::cerr << "XXX LocalMap: \n";
367 std::cerr << "XXX GlobalMap: \n";
368 PrintMap(*GlobalMap);
371 std::cerr << "Couldn't remap value: " << (void*)In << " " << *In << "\n";
372 assert(0 && "Couldn't remap value!");
376 /// ForceRenaming - The LLVM SymbolTable class autorenames globals that conflict
377 /// in the symbol table. This is good for all clients except for us. Go
378 /// through the trouble to force this back.
379 static void ForceRenaming(GlobalValue *GV, const std::string &Name) {
380 assert(GV->getName() != Name && "Can't force rename to self");
381 SymbolTable &ST = GV->getParent()->getSymbolTable();
383 // If there is a conflict, rename the conflict.
384 Value *ConflictVal = ST.lookup(GV->getType(), Name);
385 assert(ConflictVal&&"Why do we have to force rename if there is no conflic?");
386 GlobalValue *ConflictGV = cast<GlobalValue>(ConflictVal);
387 assert(ConflictGV->hasInternalLinkage() &&
388 "Not conflicting with a static global, should link instead!");
390 ConflictGV->setName(""); // Eliminate the conflict
391 GV->setName(Name); // Force the name back
392 ConflictGV->setName(Name); // This will cause ConflictGV to get renamed
393 assert(GV->getName() == Name && ConflictGV->getName() != Name &&
394 "ForceRenaming didn't work");
398 // LinkGlobals - Loop through the global variables in the src module and merge
399 // them into the dest module.
401 static bool LinkGlobals(Module *Dest, const Module *Src,
402 std::map<const Value*, Value*> &ValueMap,
403 std::multimap<std::string, GlobalVariable *> &AppendingVars,
404 std::map<std::string, GlobalValue*> &GlobalsByName,
406 // We will need a module level symbol table if the src module has a module
407 // level symbol table...
408 SymbolTable *ST = (SymbolTable*)&Dest->getSymbolTable();
410 // Loop over all of the globals in the src module, mapping them over as we go
412 for (Module::const_giterator I = Src->gbegin(), E = Src->gend(); I != E; ++I){
413 const GlobalVariable *SGV = I;
414 GlobalVariable *DGV = 0;
415 // Check to see if may have to link the global.
416 if (SGV->hasName() && !SGV->hasInternalLinkage())
417 if (!(DGV = Dest->getGlobalVariable(SGV->getName(),
418 SGV->getType()->getElementType()))) {
419 std::map<std::string, GlobalValue*>::iterator EGV =
420 GlobalsByName.find(SGV->getName());
421 if (EGV != GlobalsByName.end())
422 DGV = dyn_cast<GlobalVariable>(EGV->second);
423 if (DGV && RecursiveResolveTypes(SGV->getType(), DGV->getType(), ST, ""))
424 DGV = 0; // FIXME: gross.
427 assert(SGV->hasInitializer() || SGV->hasExternalLinkage() &&
428 "Global must either be external or have an initializer!");
430 bool SGExtern = SGV->isExternal();
431 bool DGExtern = DGV ? DGV->isExternal() : false;
433 if (!DGV || DGV->hasInternalLinkage() || SGV->hasInternalLinkage()) {
434 // No linking to be performed, simply create an identical version of the
435 // symbol over in the dest module... the initializer will be filled in
436 // later by LinkGlobalInits...
438 GlobalVariable *NewDGV =
439 new GlobalVariable(SGV->getType()->getElementType(),
440 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
441 SGV->getName(), Dest);
443 // If the LLVM runtime renamed the global, but it is an externally visible
444 // symbol, DGV must be an existing global with internal linkage. Rename
446 if (NewDGV->getName() != SGV->getName() && !NewDGV->hasInternalLinkage())
447 ForceRenaming(NewDGV, SGV->getName());
449 // Make sure to remember this mapping...
450 ValueMap.insert(std::make_pair(SGV, NewDGV));
451 if (SGV->hasAppendingLinkage())
452 // Keep track that this is an appending variable...
453 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV));
455 } else if (SGV->isExternal()) {
456 // If SGV is external or if both SGV & DGV are external.. Just link the
457 // external globals, we aren't adding anything.
458 ValueMap.insert(std::make_pair(SGV, DGV));
460 // Inherit 'const' information.
461 if (SGV->isConstant()) DGV->setConstant(true);
463 } else if (DGV->isExternal()) { // If DGV is external but SGV is not...
464 ValueMap.insert(std::make_pair(SGV, DGV));
465 DGV->setLinkage(SGV->getLinkage()); // Inherit linkage!
467 if (DGV->isConstant() && !SGV->isConstant())
468 return Error(Err, "Linking globals named '" + SGV->getName() +
469 "': declaration is const but definition is not!");
471 // Inherit 'const' information.
472 if (SGV->isConstant()) DGV->setConstant(true);
474 } else if (SGV->hasWeakLinkage() || SGV->hasLinkOnceLinkage()) {
475 // At this point we know that DGV has LinkOnce, Appending, Weak, or
476 // External linkage. If DGV is Appending, this is an error.
477 if (DGV->hasAppendingLinkage())
478 return Error(Err, "Linking globals named '" + SGV->getName() +
479 "' with 'weak' and 'appending' linkage is not allowed!");
481 if (SGV->isConstant() != DGV->isConstant())
482 return Error(Err, "Global Variable Collision on '" +
483 ToStr(SGV->getType(), Src) + " %" + SGV->getName() +
484 "' - Global variables differ in const'ness");
486 // Otherwise, just perform the link.
487 ValueMap.insert(std::make_pair(SGV, DGV));
489 // Linkonce+Weak = Weak
490 if (DGV->hasLinkOnceLinkage() && SGV->hasWeakLinkage())
491 DGV->setLinkage(SGV->getLinkage());
493 } else if (DGV->hasWeakLinkage() || DGV->hasLinkOnceLinkage()) {
494 // At this point we know that SGV has LinkOnce, Appending, or External
495 // linkage. If SGV is Appending, this is an error.
496 if (SGV->hasAppendingLinkage())
497 return Error(Err, "Linking globals named '" + SGV->getName() +
498 " ' with 'weak' and 'appending' linkage is not allowed!");
500 if (SGV->isConstant() != DGV->isConstant())
501 return Error(Err, "Global Variable Collision on '" +
502 ToStr(SGV->getType(), Src) + " %" + SGV->getName() +
503 "' - Global variables differ in const'ness");
505 if (!SGV->hasLinkOnceLinkage())
506 DGV->setLinkage(SGV->getLinkage()); // Inherit linkage!
507 ValueMap.insert(std::make_pair(SGV, DGV));
509 } else if (SGV->getLinkage() != DGV->getLinkage()) {
510 return Error(Err, "Global variables named '" + SGV->getName() +
511 "' have different linkage specifiers!");
512 // Inherit 'const' information.
513 if (SGV->isConstant()) DGV->setConstant(true);
515 } else if (SGV->hasExternalLinkage()) {
516 // Allow linking two exactly identical external global variables...
517 if (SGV->isConstant() != DGV->isConstant())
518 return Error(Err, "Global Variable Collision on '" +
519 ToStr(SGV->getType(), Src) + " %" + SGV->getName() +
520 "' - Global variables differ in const'ness");
522 if (SGV->getInitializer() != DGV->getInitializer())
523 return Error(Err, "Global Variable Collision on '" +
524 ToStr(SGV->getType(), Src) + " %" + SGV->getName() +
525 "' - External linkage globals have different initializers");
527 ValueMap.insert(std::make_pair(SGV, DGV));
528 } else if (SGV->hasAppendingLinkage()) {
529 // No linking is performed yet. Just insert a new copy of the global, and
530 // keep track of the fact that it is an appending variable in the
531 // AppendingVars map. The name is cleared out so that no linkage is
533 GlobalVariable *NewDGV =
534 new GlobalVariable(SGV->getType()->getElementType(),
535 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
538 // Make sure to remember this mapping...
539 ValueMap.insert(std::make_pair(SGV, NewDGV));
541 // Keep track that this is an appending variable...
542 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV));
544 assert(0 && "Unknown linkage!");
551 // LinkGlobalInits - Update the initializers in the Dest module now that all
552 // globals that may be referenced are in Dest.
554 static bool LinkGlobalInits(Module *Dest, const Module *Src,
555 std::map<const Value*, Value*> &ValueMap,
558 // Loop over all of the globals in the src module, mapping them over as we go
560 for (Module::const_giterator I = Src->gbegin(), E = Src->gend(); I != E; ++I){
561 const GlobalVariable *SGV = I;
563 if (SGV->hasInitializer()) { // Only process initialized GV's
564 // Figure out what the initializer looks like in the dest module...
566 cast<Constant>(RemapOperand(SGV->getInitializer(), ValueMap, 0));
568 GlobalVariable *DGV = cast<GlobalVariable>(ValueMap[SGV]);
569 if (DGV->hasInitializer()) {
570 if (SGV->hasExternalLinkage()) {
571 if (DGV->getInitializer() != SInit)
572 return Error(Err, "Global Variable Collision on '" +
573 ToStr(SGV->getType(), Src) +"':%"+SGV->getName()+
574 " - Global variables have different initializers");
575 } else if (DGV->hasLinkOnceLinkage() || DGV->hasWeakLinkage()) {
576 // Nothing is required, mapped values will take the new global
578 } else if (SGV->hasLinkOnceLinkage() || SGV->hasWeakLinkage()) {
579 // Nothing is required, mapped values will take the new global
581 } else if (DGV->hasAppendingLinkage()) {
582 assert(0 && "Appending linkage unimplemented!");
584 assert(0 && "Unknown linkage!");
587 // Copy the initializer over now...
588 DGV->setInitializer(SInit);
595 // LinkFunctionProtos - Link the functions together between the two modules,
596 // without doing function bodies... this just adds external function prototypes
597 // to the Dest function...
599 static bool LinkFunctionProtos(Module *Dest, const Module *Src,
600 std::map<const Value*, Value*> &ValueMap,
601 std::map<std::string, GlobalValue*> &GlobalsByName,
603 SymbolTable *ST = (SymbolTable*)&Dest->getSymbolTable();
605 // Loop over all of the functions in the src module, mapping them over as we
608 for (Module::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) {
609 const Function *SF = I; // SrcFunction
611 if (SF->hasName() && !SF->hasInternalLinkage()) {
612 // Check to see if may have to link the function.
613 if (!(DF = Dest->getFunction(SF->getName(), SF->getFunctionType()))) {
614 std::map<std::string, GlobalValue*>::iterator EF =
615 GlobalsByName.find(SF->getName());
616 if (EF != GlobalsByName.end())
617 DF = dyn_cast<Function>(EF->second);
618 if (DF && RecursiveResolveTypes(SF->getType(), DF->getType(), ST, ""))
619 DF = 0; // FIXME: gross.
623 if (!DF || SF->hasInternalLinkage() || DF->hasInternalLinkage()) {
624 // Function does not already exist, simply insert an function signature
625 // identical to SF into the dest module...
626 Function *NewDF = new Function(SF->getFunctionType(), SF->getLinkage(),
627 SF->getName(), Dest);
629 // If the LLVM runtime renamed the function, but it is an externally
630 // visible symbol, DF must be an existing function with internal linkage.
632 if (NewDF->getName() != SF->getName() && !NewDF->hasInternalLinkage())
633 ForceRenaming(NewDF, SF->getName());
635 // ... and remember this mapping...
636 ValueMap.insert(std::make_pair(SF, NewDF));
637 } else if (SF->isExternal()) {
638 // If SF is external or if both SF & DF are external.. Just link the
639 // external functions, we aren't adding anything.
640 ValueMap.insert(std::make_pair(SF, DF));
641 } else if (DF->isExternal()) { // If DF is external but SF is not...
642 // Link the external functions, update linkage qualifiers
643 ValueMap.insert(std::make_pair(SF, DF));
644 DF->setLinkage(SF->getLinkage());
646 } else if (SF->hasWeakLinkage() || SF->hasLinkOnceLinkage()) {
647 // At this point we know that DF has LinkOnce, Weak, or External linkage.
648 ValueMap.insert(std::make_pair(SF, DF));
650 // Linkonce+Weak = Weak
651 if (DF->hasLinkOnceLinkage() && SF->hasWeakLinkage())
652 DF->setLinkage(SF->getLinkage());
654 } else if (DF->hasWeakLinkage() || DF->hasLinkOnceLinkage()) {
655 // At this point we know that SF has LinkOnce or External linkage.
656 ValueMap.insert(std::make_pair(SF, DF));
657 if (!SF->hasLinkOnceLinkage()) // Don't inherit linkonce linkage
658 DF->setLinkage(SF->getLinkage());
660 } else if (SF->getLinkage() != DF->getLinkage()) {
661 return Error(Err, "Functions named '" + SF->getName() +
662 "' have different linkage specifiers!");
663 } else if (SF->hasExternalLinkage()) {
664 // The function is defined in both modules!!
665 return Error(Err, "Function '" +
666 ToStr(SF->getFunctionType(), Src) + "':\"" +
667 SF->getName() + "\" - Function is already defined!");
669 assert(0 && "Unknown linkage configuration found!");
675 // LinkFunctionBody - Copy the source function over into the dest function and
676 // fix up references to values. At this point we know that Dest is an external
677 // function, and that Src is not.
679 static bool LinkFunctionBody(Function *Dest, const Function *Src,
680 std::map<const Value*, Value*> &GlobalMap,
682 assert(Src && Dest && Dest->isExternal() && !Src->isExternal());
683 std::map<const Value*, Value*> LocalMap; // Map for function local values
685 // Go through and convert function arguments over...
686 Function::aiterator DI = Dest->abegin();
687 for (Function::const_aiterator I = Src->abegin(), E = Src->aend();
689 DI->setName(I->getName()); // Copy the name information over...
691 // Add a mapping to our local map
692 LocalMap.insert(std::make_pair(I, DI));
695 // Loop over all of the basic blocks, copying the instructions over...
697 for (Function::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) {
698 // Create new basic block and add to mapping and the Dest function...
699 BasicBlock *DBB = new BasicBlock(I->getName(), Dest);
700 LocalMap.insert(std::make_pair(I, DBB));
702 // Loop over all of the instructions in the src basic block, copying them
703 // over. Note that this is broken in a strict sense because the cloned
704 // instructions will still be referencing values in the Src module, not
705 // the remapped values. In our case, however, we will not get caught and
706 // so we can delay patching the values up until later...
708 for (BasicBlock::const_iterator II = I->begin(), IE = I->end();
710 Instruction *DI = II->clone();
711 DI->setName(II->getName());
712 DBB->getInstList().push_back(DI);
713 LocalMap.insert(std::make_pair(II, DI));
717 // At this point, all of the instructions and values of the function are now
718 // copied over. The only problem is that they are still referencing values in
719 // the Source function as operands. Loop through all of the operands of the
720 // functions and patch them up to point to the local versions...
722 for (Function::iterator BB = Dest->begin(), BE = Dest->end(); BB != BE; ++BB)
723 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
724 for (Instruction::op_iterator OI = I->op_begin(), OE = I->op_end();
726 *OI = RemapOperand(*OI, LocalMap, &GlobalMap);
732 // LinkFunctionBodies - Link in the function bodies that are defined in the
733 // source module into the DestModule. This consists basically of copying the
734 // function over and fixing up references to values.
736 static bool LinkFunctionBodies(Module *Dest, const Module *Src,
737 std::map<const Value*, Value*> &ValueMap,
740 // Loop over all of the functions in the src module, mapping them over as we
743 for (Module::const_iterator SF = Src->begin(), E = Src->end(); SF != E; ++SF){
744 if (!SF->isExternal()) { // No body if function is external
745 Function *DF = cast<Function>(ValueMap[SF]); // Destination function
747 // DF not external SF external?
748 if (DF->isExternal()) {
749 // Only provide the function body if there isn't one already.
750 if (LinkFunctionBody(DF, SF, ValueMap, Err))
758 // LinkAppendingVars - If there were any appending global variables, link them
759 // together now. Return true on error.
761 static bool LinkAppendingVars(Module *M,
762 std::multimap<std::string, GlobalVariable *> &AppendingVars,
763 std::string *ErrorMsg) {
764 if (AppendingVars.empty()) return false; // Nothing to do.
766 // Loop over the multimap of appending vars, processing any variables with the
767 // same name, forming a new appending global variable with both of the
768 // 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 // Create the new global variable...
797 new GlobalVariable(NewType, G1->isConstant(), G1->getLinkage(),
798 /*init*/0, First->first, M);
800 // Merge the initializer...
801 Inits.reserve(NewSize);
802 if (ConstantArray *I = dyn_cast<ConstantArray>(G1->getInitializer())) {
803 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i)
804 Inits.push_back(I->getOperand(i));
806 assert(isa<ConstantAggregateZero>(G1->getInitializer()));
807 Constant *CV = Constant::getNullValue(T1->getElementType());
808 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i)
811 if (ConstantArray *I = dyn_cast<ConstantArray>(G2->getInitializer())) {
812 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i)
813 Inits.push_back(I->getOperand(i));
815 assert(isa<ConstantAggregateZero>(G2->getInitializer()));
816 Constant *CV = Constant::getNullValue(T2->getElementType());
817 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i)
820 NG->setInitializer(ConstantArray::get(NewType, Inits));
823 // Replace any uses of the two global variables with uses of the new
826 // FIXME: This should rewrite simple/straight-forward uses such as
827 // getelementptr instructions to not use the Cast!
828 G1->replaceAllUsesWith(ConstantExpr::getCast(NG, G1->getType()));
829 G2->replaceAllUsesWith(ConstantExpr::getCast(NG, G2->getType()));
831 // Remove the two globals from the module now...
832 M->getGlobalList().erase(G1);
833 M->getGlobalList().erase(G2);
835 // Put the new global into the AppendingVars map so that we can handle
836 // linking of more than two vars...
839 AppendingVars.erase(First);
846 // LinkModules - This function links two modules together, with the resulting
847 // left module modified to be the composite of the two input modules. If an
848 // error occurs, true is returned and ErrorMsg (if not null) is set to indicate
849 // the problem. Upon failure, the Dest module could be in a modified state, and
850 // shouldn't be relied on to be consistent.
852 bool llvm::LinkModules(Module *Dest, const Module *Src, std::string *ErrorMsg) {
853 assert(Dest != 0 && "Invalid Destination module");
854 assert(Src != 0 && "Invalid Source Module");
856 if (Dest->getEndianness() == Module::AnyEndianness)
857 Dest->setEndianness(Src->getEndianness());
858 if (Dest->getPointerSize() == Module::AnyPointerSize)
859 Dest->setPointerSize(Src->getPointerSize());
861 if (Src->getEndianness() != Module::AnyEndianness &&
862 Dest->getEndianness() != Src->getEndianness())
863 std::cerr << "WARNING: Linking two modules of different endianness!\n";
864 if (Src->getPointerSize() != Module::AnyPointerSize &&
865 Dest->getPointerSize() != Src->getPointerSize())
866 std::cerr << "WARNING: Linking two modules of different pointer size!\n";
868 // Update the destination module's dependent libraries list with the libraries
869 // from the source module. There's no opportunity for duplicates here as the
870 // Module ensures that duplicate insertions are discarded.
871 Module::lib_iterator SI = Src->lib_begin();
872 Module::lib_iterator SE = Src->lib_end();
874 Dest->addLibrary(*SI);
878 // LinkTypes - Go through the symbol table of the Src module and see if any
879 // types are named in the src module that are not named in the Dst module.
880 // Make sure there are no type name conflicts.
882 if (LinkTypes(Dest, Src, ErrorMsg)) return true;
884 // ValueMap - Mapping of values from what they used to be in Src, to what they
887 std::map<const Value*, Value*> ValueMap;
889 // AppendingVars - Keep track of global variables in the destination module
890 // with appending linkage. After the module is linked together, they are
891 // appended and the module is rewritten.
893 std::multimap<std::string, GlobalVariable *> AppendingVars;
895 // GlobalsByName - The LLVM SymbolTable class fights our best efforts at
896 // linking by separating globals by type. Until PR411 is fixed, we replicate
897 // it's functionality here.
898 std::map<std::string, GlobalValue*> GlobalsByName;
900 for (Module::giterator I = Dest->gbegin(), E = Dest->gend(); I != E; ++I) {
901 // Add all of the appending globals already in the Dest module to
903 if (I->hasAppendingLinkage())
904 AppendingVars.insert(std::make_pair(I->getName(), I));
906 // Keep track of all globals by name.
907 if (!I->hasInternalLinkage() && I->hasName())
908 GlobalsByName[I->getName()] = I;
911 // Keep track of all globals by name.
912 for (Module::iterator I = Dest->begin(), E = Dest->end(); I != E; ++I)
913 if (!I->hasInternalLinkage() && I->hasName())
914 GlobalsByName[I->getName()] = I;
916 // Insert all of the globals in src into the Dest module... without linking
917 // initializers (which could refer to functions not yet mapped over).
919 if (LinkGlobals(Dest, Src, ValueMap, AppendingVars, GlobalsByName, ErrorMsg))
922 // Link the functions together between the two modules, without doing function
923 // bodies... this just adds external function prototypes to the Dest
924 // function... We do this so that when we begin processing function bodies,
925 // all of the global values that may be referenced are available in our
928 if (LinkFunctionProtos(Dest, Src, ValueMap, GlobalsByName, ErrorMsg))
931 // Update the initializers in the Dest module now that all globals that may
932 // be referenced are in Dest.
934 if (LinkGlobalInits(Dest, Src, ValueMap, ErrorMsg)) return true;
936 // Link in the function bodies that are defined in the source module into the
937 // DestModule. This consists basically of copying the function over and
938 // fixing up references to values.
940 if (LinkFunctionBodies(Dest, Src, ValueMap, ErrorMsg)) return true;
942 // If there were any appending global variables, link them together now.
944 if (LinkAppendingVars(Dest, AppendingVars, ErrorMsg)) return true;
946 // If the source library's module id is in the dependent library list of the
947 // destination library, remove it since that module is now linked in.
949 modId.set_file(Src->getModuleIdentifier());
950 if (!modId.is_empty())
951 Dest->removeLibrary(modId.get_basename());