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::FunctionTyID: {
115 if (cast<FunctionType>(DestTyT)->isVarArg() !=
116 cast<FunctionType>(SrcTyT)->isVarArg() ||
117 cast<FunctionType>(DestTyT)->getNumContainedTypes() !=
118 cast<FunctionType>(SrcTyT)->getNumContainedTypes())
120 for (unsigned i = 0, e = getFT(DestTy)->getNumContainedTypes(); i != e; ++i)
121 if (RecursiveResolveTypesI(getFT(DestTy)->getContainedType(i),
122 getFT(SrcTy)->getContainedType(i), DestST, "",
127 case Type::StructTyID: {
128 if (getST(DestTy)->getNumContainedTypes() !=
129 getST(SrcTy)->getNumContainedTypes()) return 1;
130 for (unsigned i = 0, e = getST(DestTy)->getNumContainedTypes(); i != e; ++i)
131 if (RecursiveResolveTypesI(getST(DestTy)->getContainedType(i),
132 getST(SrcTy)->getContainedType(i), DestST, "",
137 case Type::ArrayTyID: {
138 const ArrayType *DAT = cast<ArrayType>(DestTy.get());
139 const ArrayType *SAT = cast<ArrayType>(SrcTy.get());
140 if (DAT->getNumElements() != SAT->getNumElements()) return true;
141 return RecursiveResolveTypesI(DAT->getElementType(), SAT->getElementType(),
142 DestST, "", Pointers);
144 case Type::PointerTyID: {
145 // If this is a pointer type, check to see if we have already seen it. If
146 // so, we are in a recursive branch. Cut off the search now. We cannot use
147 // an associative container for this search, because the type pointers (keys
148 // 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 TypeSymbolTable *DestST,
170 const std::string &Name){
171 std::vector<std::pair<PATypeHolder, PATypeHolder> > PointerTypes;
172 return RecursiveResolveTypesI(DestTy, SrcTy, DestST, Name, PointerTypes);
176 // LinkTypes - Go through the symbol table of the Src module and see if any
177 // types are named in the src module that are not named in the Dst module.
178 // Make sure there are no type name conflicts.
179 static bool LinkTypes(Module *Dest, const Module *Src, std::string *Err) {
180 TypeSymbolTable *DestST = &Dest->getTypeSymbolTable();
181 const TypeSymbolTable *SrcST = &Src->getTypeSymbolTable();
183 // Look for a type plane for Type's...
184 TypeSymbolTable::const_iterator TI = SrcST->begin();
185 TypeSymbolTable::const_iterator TE = SrcST->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->lookup(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->lookup(Name);
215 Type *T2 = DestST->lookup(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->lookup(Name));
230 PATypeHolder T2(DestST->lookup(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 if (DelayedTypesToResolve.size() == OldSize) {
244 // Remove the symbol name from the destination.
245 DelayedTypesToResolve.pop_back();
254 static void PrintMap(const std::map<const Value*, Value*> &M) {
255 for (std::map<const Value*, Value*>::const_iterator I = M.begin(), E =M.end();
257 cerr << " Fr: " << (void*)I->first << " ";
259 cerr << " To: " << (void*)I->second << " ";
266 // RemapOperand - Use ValueMap to convert references from one module to another.
267 // This is somewhat sophisticated in that it can automatically handle constant
268 // references correctly as well.
269 static Value *RemapOperand(const Value *In,
270 std::map<const Value*, Value*> &ValueMap) {
271 std::map<const Value*,Value*>::const_iterator I = ValueMap.find(In);
272 if (I != ValueMap.end()) return I->second;
274 // Check to see if it's a constant that we are interesting in transforming.
276 if (const Constant *CPV = dyn_cast<Constant>(In)) {
277 if ((!isa<DerivedType>(CPV->getType()) && !isa<ConstantExpr>(CPV)) ||
278 isa<ConstantAggregateZero>(CPV))
279 return const_cast<Constant*>(CPV); // Simple constants stay identical.
281 if (const ConstantArray *CPA = dyn_cast<ConstantArray>(CPV)) {
282 std::vector<Constant*> Operands(CPA->getNumOperands());
283 for (unsigned i = 0, e = CPA->getNumOperands(); i != e; ++i)
284 Operands[i] =cast<Constant>(RemapOperand(CPA->getOperand(i), ValueMap));
285 Result = ConstantArray::get(cast<ArrayType>(CPA->getType()), Operands);
286 } else if (const ConstantStruct *CPS = dyn_cast<ConstantStruct>(CPV)) {
287 std::vector<Constant*> Operands(CPS->getNumOperands());
288 for (unsigned i = 0, e = CPS->getNumOperands(); i != e; ++i)
289 Operands[i] =cast<Constant>(RemapOperand(CPS->getOperand(i), ValueMap));
290 Result = ConstantStruct::get(cast<StructType>(CPS->getType()), Operands);
291 } else if (isa<ConstantPointerNull>(CPV) || isa<UndefValue>(CPV)) {
292 Result = const_cast<Constant*>(CPV);
293 } else if (isa<GlobalValue>(CPV)) {
294 Result = cast<Constant>(RemapOperand(CPV, ValueMap));
295 } else if (const ConstantPacked *CP = dyn_cast<ConstantPacked>(CPV)) {
296 std::vector<Constant*> Operands(CP->getNumOperands());
297 for (unsigned i = 0, e = CP->getNumOperands(); i != e; ++i)
298 Operands[i] = cast<Constant>(RemapOperand(CP->getOperand(i), ValueMap));
299 Result = ConstantPacked::get(Operands);
300 } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CPV)) {
301 std::vector<Constant*> Ops;
302 for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i)
303 Ops.push_back(cast<Constant>(RemapOperand(CE->getOperand(i),ValueMap)));
304 Result = CE->getWithOperands(Ops);
306 assert(0 && "Unknown type of derived type constant value!");
308 } else if (isa<InlineAsm>(In)) {
309 Result = const_cast<Value*>(In);
312 // Cache the mapping in our local map structure...
314 ValueMap.insert(std::make_pair(In, Result));
319 cerr << "LinkModules ValueMap: \n";
322 cerr << "Couldn't remap value: " << (void*)In << " " << *In << "\n";
323 assert(0 && "Couldn't remap value!");
327 /// ForceRenaming - The LLVM SymbolTable class autorenames globals that conflict
328 /// in the symbol table. This is good for all clients except for us. Go
329 /// through the trouble to force this back.
330 static void ForceRenaming(GlobalValue *GV, const std::string &Name) {
331 assert(GV->getName() != Name && "Can't force rename to self");
332 SymbolTable &ST = GV->getParent()->getValueSymbolTable();
334 // If there is a conflict, rename the conflict.
335 Value *ConflictVal = ST.lookup(GV->getType(), Name);
336 assert(ConflictVal&&"Why do we have to force rename if there is no conflic?");
337 GlobalValue *ConflictGV = cast<GlobalValue>(ConflictVal);
338 assert(ConflictGV->hasInternalLinkage() &&
339 "Not conflicting with a static global, should link instead!");
341 ConflictGV->setName(""); // Eliminate the conflict
342 GV->setName(Name); // Force the name back
343 ConflictGV->setName(Name); // This will cause ConflictGV to get renamed
344 assert(GV->getName() == Name && ConflictGV->getName() != Name &&
345 "ForceRenaming didn't work");
348 /// GetLinkageResult - This analyzes the two global values and determines what
349 /// the result will look like in the destination module. In particular, it
350 /// computes the resultant linkage type, computes whether the global in the
351 /// source should be copied over to the destination (replacing the existing
352 /// one), and computes whether this linkage is an error or not.
353 static bool GetLinkageResult(GlobalValue *Dest, GlobalValue *Src,
354 GlobalValue::LinkageTypes <, bool &LinkFromSrc,
356 assert((!Dest || !Src->hasInternalLinkage()) &&
357 "If Src has internal linkage, Dest shouldn't be set!");
359 // Linking something to nothing.
361 LT = Src->getLinkage();
362 } else if (Src->isExternal()) {
363 // If Src is external or if both Src & Drc are external.. Just link the
364 // external globals, we aren't adding anything.
365 if (Src->hasDLLImportLinkage()) {
366 // If one of GVs has DLLImport linkage, result should be dllimport'ed.
367 if (Dest->isExternal()) {
369 LT = Src->getLinkage();
371 } else if (Dest->hasExternalWeakLinkage()) {
372 //If the Dest is weak, use the source linkage
374 LT = Src->getLinkage();
377 LT = Dest->getLinkage();
379 } else if (Dest->isExternal() && !Dest->hasDLLImportLinkage()) {
380 // If Dest is external but Src is not:
382 LT = Src->getLinkage();
383 } else if (Src->hasAppendingLinkage() || Dest->hasAppendingLinkage()) {
384 if (Src->getLinkage() != Dest->getLinkage())
385 return Error(Err, "Linking globals named '" + Src->getName() +
386 "': can only link appending global with another appending global!");
387 LinkFromSrc = true; // Special cased.
388 LT = Src->getLinkage();
389 } else if (Src->hasWeakLinkage() || Src->hasLinkOnceLinkage()) {
390 // At this point we know that Dest has LinkOnce, External*, Weak, DLL* linkage.
391 if ((Dest->hasLinkOnceLinkage() && Src->hasWeakLinkage()) ||
392 Dest->hasExternalWeakLinkage()) {
394 LT = Src->getLinkage();
397 LT = Dest->getLinkage();
399 } else if (Dest->hasWeakLinkage() || Dest->hasLinkOnceLinkage()) {
400 // At this point we know that Src has External* or DLL* linkage.
401 if (Src->hasExternalWeakLinkage()) {
403 LT = Dest->getLinkage();
406 LT = GlobalValue::ExternalLinkage;
409 assert((Dest->hasExternalLinkage() ||
410 Dest->hasDLLImportLinkage() ||
411 Dest->hasDLLExportLinkage() ||
412 Dest->hasExternalWeakLinkage()) &&
413 (Src->hasExternalLinkage() ||
414 Src->hasDLLImportLinkage() ||
415 Src->hasDLLExportLinkage() ||
416 Src->hasExternalWeakLinkage()) &&
417 "Unexpected linkage type!");
418 return Error(Err, "Linking globals named '" + Src->getName() +
419 "': symbol multiply defined!");
424 // LinkGlobals - Loop through the global variables in the src module and merge
425 // them into the dest module.
426 static bool LinkGlobals(Module *Dest, Module *Src,
427 std::map<const Value*, Value*> &ValueMap,
428 std::multimap<std::string, GlobalVariable *> &AppendingVars,
429 std::map<std::string, GlobalValue*> &GlobalsByName,
431 // We will need a module level symbol table if the src module has a module
432 // level symbol table...
433 TypeSymbolTable *TST = &Dest->getTypeSymbolTable();
435 // Loop over all of the globals in the src module, mapping them over as we go
436 for (Module::global_iterator I = Src->global_begin(), E = Src->global_end();
438 GlobalVariable *SGV = I;
439 GlobalVariable *DGV = 0;
440 // Check to see if may have to link the global.
441 if (SGV->hasName() && !SGV->hasInternalLinkage())
442 if (!(DGV = Dest->getGlobalVariable(SGV->getName(),
443 SGV->getType()->getElementType()))) {
444 std::map<std::string, GlobalValue*>::iterator EGV =
445 GlobalsByName.find(SGV->getName());
446 if (EGV != GlobalsByName.end())
447 DGV = dyn_cast<GlobalVariable>(EGV->second);
449 // If types don't agree due to opaque types, try to resolve them.
450 RecursiveResolveTypes(SGV->getType(), DGV->getType(), TST, "");
453 if (DGV && DGV->hasInternalLinkage())
456 assert(SGV->hasInitializer() || SGV->hasExternalWeakLinkage() ||
457 SGV->hasExternalLinkage() || SGV->hasDLLImportLinkage() &&
458 "Global must either be external or have an initializer!");
460 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage;
461 bool LinkFromSrc = false;
462 if (GetLinkageResult(DGV, SGV, NewLinkage, LinkFromSrc, Err))
466 // No linking to be performed, simply create an identical version of the
467 // symbol over in the dest module... the initializer will be filled in
468 // later by LinkGlobalInits...
469 GlobalVariable *NewDGV =
470 new GlobalVariable(SGV->getType()->getElementType(),
471 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
472 SGV->getName(), Dest);
473 // Propagate alignment info.
474 NewDGV->setAlignment(SGV->getAlignment());
476 // If the LLVM runtime renamed the global, but it is an externally visible
477 // symbol, DGV must be an existing global with internal linkage. Rename
479 if (NewDGV->getName() != SGV->getName() && !NewDGV->hasInternalLinkage())
480 ForceRenaming(NewDGV, SGV->getName());
482 // Make sure to remember this mapping...
483 ValueMap.insert(std::make_pair(SGV, NewDGV));
484 if (SGV->hasAppendingLinkage())
485 // Keep track that this is an appending variable...
486 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV));
487 } else if (DGV->hasAppendingLinkage()) {
488 // No linking is performed yet. Just insert a new copy of the global, and
489 // keep track of the fact that it is an appending variable in the
490 // AppendingVars map. The name is cleared out so that no linkage is
492 GlobalVariable *NewDGV =
493 new GlobalVariable(SGV->getType()->getElementType(),
494 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
497 // Propagate alignment info.
498 NewDGV->setAlignment(std::max(DGV->getAlignment(), SGV->getAlignment()));
500 // Make sure to remember this mapping...
501 ValueMap.insert(std::make_pair(SGV, NewDGV));
503 // Keep track that this is an appending variable...
504 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV));
506 // Propagate alignment info.
507 DGV->setAlignment(std::max(DGV->getAlignment(), SGV->getAlignment()));
509 // Otherwise, perform the mapping as instructed by GetLinkageResult. If
510 // the types don't match, and if we are to link from the source, nuke DGV
511 // and create a new one of the appropriate type.
512 if (SGV->getType() != DGV->getType() && LinkFromSrc) {
513 GlobalVariable *NewDGV =
514 new GlobalVariable(SGV->getType()->getElementType(),
515 DGV->isConstant(), DGV->getLinkage());
516 NewDGV->setAlignment(DGV->getAlignment());
517 Dest->getGlobalList().insert(DGV, NewDGV);
518 DGV->replaceAllUsesWith(
519 ConstantExpr::getBitCast(NewDGV, DGV->getType()));
520 DGV->eraseFromParent();
521 NewDGV->setName(SGV->getName());
525 DGV->setLinkage(NewLinkage);
528 // Inherit const as appropriate
529 DGV->setConstant(SGV->isConstant());
530 DGV->setInitializer(0);
532 if (SGV->isConstant() && !DGV->isConstant()) {
533 if (DGV->isExternal())
534 DGV->setConstant(true);
536 SGV->setLinkage(GlobalValue::ExternalLinkage);
537 SGV->setInitializer(0);
541 std::make_pair(SGV, ConstantExpr::getBitCast(DGV, SGV->getType())));
548 // LinkGlobalInits - Update the initializers in the Dest module now that all
549 // globals that may be referenced are in Dest.
550 static bool LinkGlobalInits(Module *Dest, const Module *Src,
551 std::map<const Value*, Value*> &ValueMap,
554 // Loop over all of the globals in the src module, mapping them over as we go
555 for (Module::const_global_iterator I = Src->global_begin(),
556 E = Src->global_end(); I != E; ++I) {
557 const GlobalVariable *SGV = I;
559 if (SGV->hasInitializer()) { // Only process initialized GV's
560 // Figure out what the initializer looks like in the dest module...
562 cast<Constant>(RemapOperand(SGV->getInitializer(), ValueMap));
564 GlobalVariable *DGV = cast<GlobalVariable>(ValueMap[SGV]);
565 if (DGV->hasInitializer()) {
566 if (SGV->hasExternalLinkage()) {
567 if (DGV->getInitializer() != SInit)
568 return Error(Err, "Global Variable Collision on '" +
569 ToStr(SGV->getType(), Src) +"':%"+SGV->getName()+
570 " - Global variables have different initializers");
571 } else if (DGV->hasLinkOnceLinkage() || DGV->hasWeakLinkage()) {
572 // Nothing is required, mapped values will take the new global
574 } else if (SGV->hasLinkOnceLinkage() || SGV->hasWeakLinkage()) {
575 // Nothing is required, mapped values will take the new global
577 } else if (DGV->hasAppendingLinkage()) {
578 assert(0 && "Appending linkage unimplemented!");
580 assert(0 && "Unknown linkage!");
583 // Copy the initializer over now...
584 DGV->setInitializer(SInit);
591 // LinkFunctionProtos - Link the functions together between the two modules,
592 // without doing function bodies... this just adds external function prototypes
593 // to the Dest function...
595 static bool LinkFunctionProtos(Module *Dest, const Module *Src,
596 std::map<const Value*, Value*> &ValueMap,
597 std::map<std::string,
598 GlobalValue*> &GlobalsByName,
600 TypeSymbolTable *TST = &Dest->getTypeSymbolTable();
602 // Loop over all of the functions in the src module, mapping them over as we
604 for (Module::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) {
605 const Function *SF = I; // SrcFunction
607 if (SF->hasName() && !SF->hasInternalLinkage()) {
608 // Check to see if may have to link the function.
609 if (!(DF = Dest->getFunction(SF->getName(), SF->getFunctionType()))) {
610 std::map<std::string, GlobalValue*>::iterator EF =
611 GlobalsByName.find(SF->getName());
612 if (EF != GlobalsByName.end())
613 DF = dyn_cast<Function>(EF->second);
614 if (DF && RecursiveResolveTypes(SF->getType(), DF->getType(), TST, ""))
615 DF = 0; // FIXME: gross.
619 if (!DF || SF->hasInternalLinkage() || DF->hasInternalLinkage()) {
620 // Function does not already exist, simply insert an function signature
621 // identical to SF into the dest module...
622 Function *NewDF = new Function(SF->getFunctionType(), SF->getLinkage(),
623 SF->getName(), Dest);
624 NewDF->setCallingConv(SF->getCallingConv());
626 // If the LLVM runtime renamed the function, but it is an externally
627 // visible symbol, DF must be an existing function with internal linkage.
629 if (NewDF->getName() != SF->getName() && !NewDF->hasInternalLinkage())
630 ForceRenaming(NewDF, SF->getName());
632 // ... and remember this mapping...
633 ValueMap.insert(std::make_pair(SF, NewDF));
634 } else if (SF->isExternal()) {
635 // If SF is external or if both SF & DF are external.. Just link the
636 // external functions, we aren't adding anything.
637 if (SF->hasDLLImportLinkage()) {
638 if (DF->isExternal()) {
639 ValueMap.insert(std::make_pair(SF, DF));
640 DF->setLinkage(SF->getLinkage());
643 ValueMap.insert(std::make_pair(SF, DF));
645 } else if (DF->isExternal() && !DF->hasDLLImportLinkage()) {
646 // If DF is external but SF is not...
647 // Link the external functions, update linkage qualifiers
648 ValueMap.insert(std::make_pair(SF, DF));
649 DF->setLinkage(SF->getLinkage());
650 } else if (SF->hasWeakLinkage() || SF->hasLinkOnceLinkage()) {
651 // At this point we know that DF has LinkOnce, Weak, or External* linkage.
652 ValueMap.insert(std::make_pair(SF, DF));
654 // Linkonce+Weak = Weak
655 // *+External Weak = *
656 if ((DF->hasLinkOnceLinkage() && SF->hasWeakLinkage()) ||
657 DF->hasExternalWeakLinkage())
658 DF->setLinkage(SF->getLinkage());
661 } else if (DF->hasWeakLinkage() || DF->hasLinkOnceLinkage()) {
662 // At this point we know that SF has LinkOnce or External* linkage.
663 ValueMap.insert(std::make_pair(SF, DF));
664 if (!SF->hasLinkOnceLinkage() && !SF->hasExternalWeakLinkage())
665 // Don't inherit linkonce & external weak linkage
666 DF->setLinkage(SF->getLinkage());
667 } else if (SF->getLinkage() != DF->getLinkage()) {
668 return Error(Err, "Functions named '" + SF->getName() +
669 "' have different linkage specifiers!");
670 } else if (SF->hasExternalLinkage()) {
671 // The function is defined in both modules!!
672 return Error(Err, "Function '" +
673 ToStr(SF->getFunctionType(), Src) + "':\"" +
674 SF->getName() + "\" - Function is already defined!");
676 assert(0 && "Unknown linkage configuration found!");
682 // LinkFunctionBody - Copy the source function over into the dest function and
683 // fix up references to values. At this point we know that Dest is an external
684 // function, and that Src is not.
685 static bool LinkFunctionBody(Function *Dest, Function *Src,
686 std::map<const Value*, Value*> &GlobalMap,
688 assert(Src && Dest && Dest->isExternal() && !Src->isExternal());
690 // Go through and convert function arguments over, remembering the mapping.
691 Function::arg_iterator DI = Dest->arg_begin();
692 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end();
694 DI->setName(I->getName()); // Copy the name information over...
696 // Add a mapping to our local map
697 GlobalMap.insert(std::make_pair(I, DI));
700 // Splice the body of the source function into the dest function.
701 Dest->getBasicBlockList().splice(Dest->end(), Src->getBasicBlockList());
703 // At this point, all of the instructions and values of the function are now
704 // copied over. The only problem is that they are still referencing values in
705 // the Source function as operands. Loop through all of the operands of the
706 // functions and patch them up to point to the local versions...
708 for (Function::iterator BB = Dest->begin(), BE = Dest->end(); BB != BE; ++BB)
709 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
710 for (Instruction::op_iterator OI = I->op_begin(), OE = I->op_end();
712 if (!isa<Instruction>(*OI) && !isa<BasicBlock>(*OI))
713 *OI = RemapOperand(*OI, GlobalMap);
715 // There is no need to map the arguments anymore.
716 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end();
724 // LinkFunctionBodies - Link in the function bodies that are defined in the
725 // source module into the DestModule. This consists basically of copying the
726 // function over and fixing up references to values.
727 static bool LinkFunctionBodies(Module *Dest, Module *Src,
728 std::map<const Value*, Value*> &ValueMap,
731 // Loop over all of the functions in the src module, mapping them over as we
733 for (Module::iterator SF = Src->begin(), E = Src->end(); SF != E; ++SF) {
734 if (!SF->isExternal()) { // No body if function is external
735 Function *DF = cast<Function>(ValueMap[SF]); // Destination function
737 // DF not external SF external?
738 if (DF->isExternal()) {
739 // Only provide the function body if there isn't one already.
740 if (LinkFunctionBody(DF, SF, ValueMap, Err))
748 // LinkAppendingVars - If there were any appending global variables, link them
749 // together now. Return true on error.
750 static bool LinkAppendingVars(Module *M,
751 std::multimap<std::string, GlobalVariable *> &AppendingVars,
752 std::string *ErrorMsg) {
753 if (AppendingVars.empty()) return false; // Nothing to do.
755 // Loop over the multimap of appending vars, processing any variables with the
756 // same name, forming a new appending global variable with both of the
757 // initializers merged together, then rewrite references to the old variables
759 std::vector<Constant*> Inits;
760 while (AppendingVars.size() > 1) {
761 // Get the first two elements in the map...
762 std::multimap<std::string,
763 GlobalVariable*>::iterator Second = AppendingVars.begin(), First=Second++;
765 // If the first two elements are for different names, there is no pair...
766 // Otherwise there is a pair, so link them together...
767 if (First->first == Second->first) {
768 GlobalVariable *G1 = First->second, *G2 = Second->second;
769 const ArrayType *T1 = cast<ArrayType>(G1->getType()->getElementType());
770 const ArrayType *T2 = cast<ArrayType>(G2->getType()->getElementType());
772 // Check to see that they two arrays agree on type...
773 if (T1->getElementType() != T2->getElementType())
774 return Error(ErrorMsg,
775 "Appending variables with different element types need to be linked!");
776 if (G1->isConstant() != G2->isConstant())
777 return Error(ErrorMsg,
778 "Appending variables linked with different const'ness!");
780 unsigned NewSize = T1->getNumElements() + T2->getNumElements();
781 ArrayType *NewType = ArrayType::get(T1->getElementType(), NewSize);
783 G1->setName(""); // Clear G1's name in case of a conflict!
785 // Create the new global variable...
787 new GlobalVariable(NewType, G1->isConstant(), G1->getLinkage(),
788 /*init*/0, First->first, M);
790 // Merge the initializer...
791 Inits.reserve(NewSize);
792 if (ConstantArray *I = dyn_cast<ConstantArray>(G1->getInitializer())) {
793 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i)
794 Inits.push_back(I->getOperand(i));
796 assert(isa<ConstantAggregateZero>(G1->getInitializer()));
797 Constant *CV = Constant::getNullValue(T1->getElementType());
798 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i)
801 if (ConstantArray *I = dyn_cast<ConstantArray>(G2->getInitializer())) {
802 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i)
803 Inits.push_back(I->getOperand(i));
805 assert(isa<ConstantAggregateZero>(G2->getInitializer()));
806 Constant *CV = Constant::getNullValue(T2->getElementType());
807 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i)
810 NG->setInitializer(ConstantArray::get(NewType, Inits));
813 // Replace any uses of the two global variables with uses of the new
816 // FIXME: This should rewrite simple/straight-forward uses such as
817 // getelementptr instructions to not use the Cast!
818 G1->replaceAllUsesWith(ConstantExpr::getBitCast(NG, G1->getType()));
819 G2->replaceAllUsesWith(ConstantExpr::getBitCast(NG, G2->getType()));
821 // Remove the two globals from the module now...
822 M->getGlobalList().erase(G1);
823 M->getGlobalList().erase(G2);
825 // Put the new global into the AppendingVars map so that we can handle
826 // linking of more than two vars...
829 AppendingVars.erase(First);
836 // LinkModules - This function links two modules together, with the resulting
837 // left module modified to be the composite of the two input modules. If an
838 // error occurs, true is returned and ErrorMsg (if not null) is set to indicate
839 // the problem. Upon failure, the Dest module could be in a modified state, and
840 // shouldn't be relied on to be consistent.
842 Linker::LinkModules(Module *Dest, Module *Src, std::string *ErrorMsg) {
843 assert(Dest != 0 && "Invalid Destination module");
844 assert(Src != 0 && "Invalid Source Module");
846 if (Dest->getEndianness() == Module::AnyEndianness)
847 Dest->setEndianness(Src->getEndianness());
848 if (Dest->getPointerSize() == Module::AnyPointerSize)
849 Dest->setPointerSize(Src->getPointerSize());
850 if (Dest->getTargetTriple().empty())
851 Dest->setTargetTriple(Src->getTargetTriple());
853 if (Src->getEndianness() != Module::AnyEndianness &&
854 Dest->getEndianness() != Src->getEndianness())
855 cerr << "WARNING: Linking two modules of different endianness!\n";
856 if (Src->getPointerSize() != Module::AnyPointerSize &&
857 Dest->getPointerSize() != Src->getPointerSize())
858 cerr << "WARNING: Linking two modules of different pointer size!\n";
859 if (!Src->getTargetTriple().empty() &&
860 Dest->getTargetTriple() != Src->getTargetTriple())
861 cerr << "WARNING: Linking two modules of different target triples!\n";
863 if (!Src->getModuleInlineAsm().empty()) {
864 if (Dest->getModuleInlineAsm().empty())
865 Dest->setModuleInlineAsm(Src->getModuleInlineAsm());
867 Dest->setModuleInlineAsm(Dest->getModuleInlineAsm()+"\n"+
868 Src->getModuleInlineAsm());
871 // Update the destination module's dependent libraries list with the libraries
872 // from the source module. There's no opportunity for duplicates here as the
873 // Module ensures that duplicate insertions are discarded.
874 Module::lib_iterator SI = Src->lib_begin();
875 Module::lib_iterator SE = Src->lib_end();
877 Dest->addLibrary(*SI);
881 // LinkTypes - Go through the symbol table of the Src module and see if any
882 // types are named in the src module that are not named in the Dst module.
883 // Make sure there are no type name conflicts.
884 if (LinkTypes(Dest, Src, ErrorMsg)) return true;
886 // ValueMap - Mapping of values from what they used to be in Src, to what they
888 std::map<const Value*, Value*> ValueMap;
890 // AppendingVars - Keep track of global variables in the destination module
891 // with appending linkage. After the module is linked together, they are
892 // 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::global_iterator I = Dest->global_begin(), E = Dest->global_end();
902 // Add all of the appending globals already in the Dest module to
904 if (I->hasAppendingLinkage())
905 AppendingVars.insert(std::make_pair(I->getName(), I));
907 // Keep track of all globals by name.
908 if (!I->hasInternalLinkage() && I->hasName())
909 GlobalsByName[I->getName()] = I;
912 // Keep track of all globals by name.
913 for (Module::iterator I = Dest->begin(), E = Dest->end(); I != E; ++I)
914 if (!I->hasInternalLinkage() && I->hasName())
915 GlobalsByName[I->getName()] = I;
917 // Insert all of the globals in src into the Dest module... without linking
918 // 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
927 if (LinkFunctionProtos(Dest, Src, ValueMap, GlobalsByName, ErrorMsg))
930 // Update the initializers in the Dest module now that all globals that may
931 // be referenced are in Dest.
932 if (LinkGlobalInits(Dest, Src, ValueMap, ErrorMsg)) return true;
934 // Link in the function bodies that are defined in the source module into the
935 // DestModule. This consists basically of copying the function over and
936 // fixing up references to values.
937 if (LinkFunctionBodies(Dest, Src, ValueMap, ErrorMsg)) return true;
939 // If there were any appending global variables, link them together now.
940 if (LinkAppendingVars(Dest, AppendingVars, ErrorMsg)) return true;
942 // If the source library's module id is in the dependent library list of the
943 // destination library, remove it since that module is now linked in.
945 modId.set(Src->getModuleIdentifier());
946 if (!modId.isEmpty())
947 Dest->removeLibrary(modId.getBasename());