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/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 ValueMap to convert references from one module to another.
279 // This is somewhat sophisticated in that it can automatically handle constant
280 // references correctly as well...
282 static Value *RemapOperand(const Value *In,
283 std::map<const Value*, Value*> &ValueMap) {
284 std::map<const Value*,Value*>::const_iterator I = ValueMap.find(In);
285 if (I != ValueMap.end()) return I->second;
287 // Check to see if it's a constant that we are interesting in transforming.
288 if (const Constant *CPV = dyn_cast<Constant>(In)) {
289 if ((!isa<DerivedType>(CPV->getType()) && !isa<ConstantExpr>(CPV)) ||
290 isa<ConstantAggregateZero>(CPV))
291 return const_cast<Constant*>(CPV); // Simple constants stay identical.
293 Constant *Result = 0;
295 if (const ConstantArray *CPA = dyn_cast<ConstantArray>(CPV)) {
296 std::vector<Constant*> Operands(CPA->getNumOperands());
297 for (unsigned i = 0, e = CPA->getNumOperands(); i != e; ++i)
298 Operands[i] =cast<Constant>(RemapOperand(CPA->getOperand(i), ValueMap));
299 Result = ConstantArray::get(cast<ArrayType>(CPA->getType()), Operands);
300 } else if (const ConstantStruct *CPS = dyn_cast<ConstantStruct>(CPV)) {
301 std::vector<Constant*> Operands(CPS->getNumOperands());
302 for (unsigned i = 0, e = CPS->getNumOperands(); i != e; ++i)
303 Operands[i] =cast<Constant>(RemapOperand(CPS->getOperand(i), ValueMap));
304 Result = ConstantStruct::get(cast<StructType>(CPS->getType()), Operands);
305 } else if (isa<ConstantPointerNull>(CPV) || isa<UndefValue>(CPV)) {
306 Result = const_cast<Constant*>(CPV);
307 } else if (isa<GlobalValue>(CPV)) {
308 Result = cast<Constant>(RemapOperand(CPV, ValueMap));
309 } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CPV)) {
310 if (CE->getOpcode() == Instruction::GetElementPtr) {
311 Value *Ptr = RemapOperand(CE->getOperand(0), ValueMap);
312 std::vector<Constant*> Indices;
313 Indices.reserve(CE->getNumOperands()-1);
314 for (unsigned i = 1, e = CE->getNumOperands(); i != e; ++i)
315 Indices.push_back(cast<Constant>(RemapOperand(CE->getOperand(i),
318 Result = ConstantExpr::getGetElementPtr(cast<Constant>(Ptr), Indices);
319 } else if (CE->getNumOperands() == 1) {
321 assert(CE->getOpcode() == Instruction::Cast);
322 Value *V = RemapOperand(CE->getOperand(0), ValueMap);
323 Result = ConstantExpr::getCast(cast<Constant>(V), CE->getType());
324 } else if (CE->getNumOperands() == 3) {
325 // Select instruction
326 assert(CE->getOpcode() == Instruction::Select);
327 Value *V1 = RemapOperand(CE->getOperand(0), ValueMap);
328 Value *V2 = RemapOperand(CE->getOperand(1), ValueMap);
329 Value *V3 = RemapOperand(CE->getOperand(2), ValueMap);
330 Result = ConstantExpr::getSelect(cast<Constant>(V1), cast<Constant>(V2),
332 } else if (CE->getNumOperands() == 2) {
333 // Binary operator...
334 Value *V1 = RemapOperand(CE->getOperand(0), ValueMap);
335 Value *V2 = RemapOperand(CE->getOperand(1), ValueMap);
337 Result = ConstantExpr::get(CE->getOpcode(), cast<Constant>(V1),
340 assert(0 && "Unknown constant expr type!");
344 assert(0 && "Unknown type of derived type constant value!");
347 // Cache the mapping in our local map structure...
348 ValueMap.insert(std::make_pair(In, Result));
352 std::cerr << "LinkModules ValueMap: \n";
355 std::cerr << "Couldn't remap value: " << (void*)In << " " << *In << "\n";
356 assert(0 && "Couldn't remap value!");
360 /// ForceRenaming - The LLVM SymbolTable class autorenames globals that conflict
361 /// in the symbol table. This is good for all clients except for us. Go
362 /// through the trouble to force this back.
363 static void ForceRenaming(GlobalValue *GV, const std::string &Name) {
364 assert(GV->getName() != Name && "Can't force rename to self");
365 SymbolTable &ST = GV->getParent()->getSymbolTable();
367 // If there is a conflict, rename the conflict.
368 Value *ConflictVal = ST.lookup(GV->getType(), Name);
369 assert(ConflictVal&&"Why do we have to force rename if there is no conflic?");
370 GlobalValue *ConflictGV = cast<GlobalValue>(ConflictVal);
371 assert(ConflictGV->hasInternalLinkage() &&
372 "Not conflicting with a static global, should link instead!");
374 ConflictGV->setName(""); // Eliminate the conflict
375 GV->setName(Name); // Force the name back
376 ConflictGV->setName(Name); // This will cause ConflictGV to get renamed
377 assert(GV->getName() == Name && ConflictGV->getName() != Name &&
378 "ForceRenaming didn't work");
382 // LinkGlobals - Loop through the global variables in the src module and merge
383 // them into the dest module.
385 static bool LinkGlobals(Module *Dest, const Module *Src,
386 std::map<const Value*, Value*> &ValueMap,
387 std::multimap<std::string, GlobalVariable *> &AppendingVars,
388 std::map<std::string, GlobalValue*> &GlobalsByName,
390 // We will need a module level symbol table if the src module has a module
391 // level symbol table...
392 SymbolTable *ST = (SymbolTable*)&Dest->getSymbolTable();
394 // Loop over all of the globals in the src module, mapping them over as we go
396 for (Module::const_giterator I = Src->gbegin(), E = Src->gend(); I != E; ++I){
397 const GlobalVariable *SGV = I;
398 GlobalVariable *DGV = 0;
399 // Check to see if may have to link the global.
400 if (SGV->hasName() && !SGV->hasInternalLinkage())
401 if (!(DGV = Dest->getGlobalVariable(SGV->getName(),
402 SGV->getType()->getElementType()))) {
403 std::map<std::string, GlobalValue*>::iterator EGV =
404 GlobalsByName.find(SGV->getName());
405 if (EGV != GlobalsByName.end())
406 DGV = dyn_cast<GlobalVariable>(EGV->second);
407 if (DGV && RecursiveResolveTypes(SGV->getType(), DGV->getType(), ST, ""))
408 DGV = 0; // FIXME: gross.
411 assert(SGV->hasInitializer() || SGV->hasExternalLinkage() &&
412 "Global must either be external or have an initializer!");
414 bool SGExtern = SGV->isExternal();
415 bool DGExtern = DGV ? DGV->isExternal() : false;
417 if (!DGV || DGV->hasInternalLinkage() || SGV->hasInternalLinkage()) {
418 // No linking to be performed, simply create an identical version of the
419 // symbol over in the dest module... the initializer will be filled in
420 // later by LinkGlobalInits...
422 GlobalVariable *NewDGV =
423 new GlobalVariable(SGV->getType()->getElementType(),
424 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
425 SGV->getName(), Dest);
427 // If the LLVM runtime renamed the global, but it is an externally visible
428 // symbol, DGV must be an existing global with internal linkage. Rename
430 if (NewDGV->getName() != SGV->getName() && !NewDGV->hasInternalLinkage())
431 ForceRenaming(NewDGV, SGV->getName());
433 // Make sure to remember this mapping...
434 ValueMap.insert(std::make_pair(SGV, NewDGV));
435 if (SGV->hasAppendingLinkage())
436 // Keep track that this is an appending variable...
437 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV));
439 } else if (SGV->isExternal()) {
440 // If SGV is external or if both SGV & DGV are external.. Just link the
441 // external globals, we aren't adding anything.
442 ValueMap.insert(std::make_pair(SGV, DGV));
444 // Inherit 'const' information.
445 if (SGV->isConstant()) DGV->setConstant(true);
447 } else if (DGV->isExternal()) { // If DGV is external but SGV is not...
448 ValueMap.insert(std::make_pair(SGV, DGV));
449 DGV->setLinkage(SGV->getLinkage()); // Inherit linkage!
451 if (DGV->isConstant() && !SGV->isConstant())
452 return Error(Err, "Linking globals named '" + SGV->getName() +
453 "': declaration is const but definition is not!");
455 // Inherit 'const' information.
456 if (SGV->isConstant()) DGV->setConstant(true);
458 } else if (SGV->hasWeakLinkage() || SGV->hasLinkOnceLinkage()) {
459 // At this point we know that DGV has LinkOnce, Appending, Weak, or
460 // External linkage. If DGV is Appending, this is an error.
461 if (DGV->hasAppendingLinkage())
462 return Error(Err, "Linking globals named '" + SGV->getName() +
463 "' with 'weak' and 'appending' linkage is not allowed!");
465 if (SGV->isConstant() != DGV->isConstant())
466 return Error(Err, "Global Variable Collision on '" +
467 ToStr(SGV->getType(), Src) + " %" + SGV->getName() +
468 "' - Global variables differ in const'ness");
470 // Otherwise, just perform the link.
471 ValueMap.insert(std::make_pair(SGV, DGV));
473 // Linkonce+Weak = Weak
474 if (DGV->hasLinkOnceLinkage() && SGV->hasWeakLinkage())
475 DGV->setLinkage(SGV->getLinkage());
477 } else if (DGV->hasWeakLinkage() || DGV->hasLinkOnceLinkage()) {
478 // At this point we know that SGV has LinkOnce, Appending, or External
479 // linkage. If SGV is Appending, this is an error.
480 if (SGV->hasAppendingLinkage())
481 return Error(Err, "Linking globals named '" + SGV->getName() +
482 " ' with 'weak' and 'appending' linkage is not allowed!");
484 if (SGV->isConstant() != DGV->isConstant())
485 return Error(Err, "Global Variable Collision on '" +
486 ToStr(SGV->getType(), Src) + " %" + SGV->getName() +
487 "' - Global variables differ in const'ness");
489 if (!SGV->hasLinkOnceLinkage())
490 DGV->setLinkage(SGV->getLinkage()); // Inherit linkage!
491 ValueMap.insert(std::make_pair(SGV, DGV));
493 } else if (SGV->getLinkage() != DGV->getLinkage()) {
494 return Error(Err, "Global variables named '" + SGV->getName() +
495 "' have different linkage specifiers!");
496 // Inherit 'const' information.
497 if (SGV->isConstant()) DGV->setConstant(true);
499 } else if (SGV->hasExternalLinkage()) {
500 // Allow linking two exactly identical external global variables...
501 if (SGV->isConstant() != DGV->isConstant())
502 return Error(Err, "Global Variable Collision on '" +
503 ToStr(SGV->getType(), Src) + " %" + SGV->getName() +
504 "' - Global variables differ in const'ness");
506 if (SGV->getInitializer() != DGV->getInitializer())
507 return Error(Err, "Global Variable Collision on '" +
508 ToStr(SGV->getType(), Src) + " %" + SGV->getName() +
509 "' - External linkage globals have different initializers");
511 ValueMap.insert(std::make_pair(SGV, DGV));
512 } else if (SGV->hasAppendingLinkage()) {
513 // No linking is performed yet. Just insert a new copy of the global, and
514 // keep track of the fact that it is an appending variable in the
515 // AppendingVars map. The name is cleared out so that no linkage is
517 GlobalVariable *NewDGV =
518 new GlobalVariable(SGV->getType()->getElementType(),
519 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
522 // Make sure to remember this mapping...
523 ValueMap.insert(std::make_pair(SGV, NewDGV));
525 // Keep track that this is an appending variable...
526 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV));
528 assert(0 && "Unknown linkage!");
535 // LinkGlobalInits - Update the initializers in the Dest module now that all
536 // globals that may be referenced are in Dest.
538 static bool LinkGlobalInits(Module *Dest, const Module *Src,
539 std::map<const Value*, Value*> &ValueMap,
542 // Loop over all of the globals in the src module, mapping them over as we go
544 for (Module::const_giterator I = Src->gbegin(), E = Src->gend(); I != E; ++I){
545 const GlobalVariable *SGV = I;
547 if (SGV->hasInitializer()) { // Only process initialized GV's
548 // Figure out what the initializer looks like in the dest module...
550 cast<Constant>(RemapOperand(SGV->getInitializer(), ValueMap));
552 GlobalVariable *DGV = cast<GlobalVariable>(ValueMap[SGV]);
553 if (DGV->hasInitializer()) {
554 if (SGV->hasExternalLinkage()) {
555 if (DGV->getInitializer() != SInit)
556 return Error(Err, "Global Variable Collision on '" +
557 ToStr(SGV->getType(), Src) +"':%"+SGV->getName()+
558 " - Global variables have different initializers");
559 } else if (DGV->hasLinkOnceLinkage() || DGV->hasWeakLinkage()) {
560 // Nothing is required, mapped values will take the new global
562 } else if (SGV->hasLinkOnceLinkage() || SGV->hasWeakLinkage()) {
563 // Nothing is required, mapped values will take the new global
565 } else if (DGV->hasAppendingLinkage()) {
566 assert(0 && "Appending linkage unimplemented!");
568 assert(0 && "Unknown linkage!");
571 // Copy the initializer over now...
572 DGV->setInitializer(SInit);
579 // LinkFunctionProtos - Link the functions together between the two modules,
580 // without doing function bodies... this just adds external function prototypes
581 // to the Dest function...
583 static bool LinkFunctionProtos(Module *Dest, const Module *Src,
584 std::map<const Value*, Value*> &ValueMap,
585 std::map<std::string, GlobalValue*> &GlobalsByName,
587 SymbolTable *ST = (SymbolTable*)&Dest->getSymbolTable();
589 // Loop over all of the functions in the src module, mapping them over as we
592 for (Module::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) {
593 const Function *SF = I; // SrcFunction
595 if (SF->hasName() && !SF->hasInternalLinkage()) {
596 // Check to see if may have to link the function.
597 if (!(DF = Dest->getFunction(SF->getName(), SF->getFunctionType()))) {
598 std::map<std::string, GlobalValue*>::iterator EF =
599 GlobalsByName.find(SF->getName());
600 if (EF != GlobalsByName.end())
601 DF = dyn_cast<Function>(EF->second);
602 if (DF && RecursiveResolveTypes(SF->getType(), DF->getType(), ST, ""))
603 DF = 0; // FIXME: gross.
607 if (!DF || SF->hasInternalLinkage() || DF->hasInternalLinkage()) {
608 // Function does not already exist, simply insert an function signature
609 // identical to SF into the dest module...
610 Function *NewDF = new Function(SF->getFunctionType(), SF->getLinkage(),
611 SF->getName(), Dest);
613 // If the LLVM runtime renamed the function, but it is an externally
614 // visible symbol, DF must be an existing function with internal linkage.
616 if (NewDF->getName() != SF->getName() && !NewDF->hasInternalLinkage())
617 ForceRenaming(NewDF, SF->getName());
619 // ... and remember this mapping...
620 ValueMap.insert(std::make_pair(SF, NewDF));
621 } else if (SF->isExternal()) {
622 // If SF is external or if both SF & DF are external.. Just link the
623 // external functions, we aren't adding anything.
624 ValueMap.insert(std::make_pair(SF, DF));
625 } else if (DF->isExternal()) { // If DF is external but SF is not...
626 // Link the external functions, update linkage qualifiers
627 ValueMap.insert(std::make_pair(SF, DF));
628 DF->setLinkage(SF->getLinkage());
630 } else if (SF->hasWeakLinkage() || SF->hasLinkOnceLinkage()) {
631 // At this point we know that DF has LinkOnce, Weak, or External linkage.
632 ValueMap.insert(std::make_pair(SF, DF));
634 // Linkonce+Weak = Weak
635 if (DF->hasLinkOnceLinkage() && SF->hasWeakLinkage())
636 DF->setLinkage(SF->getLinkage());
638 } else if (DF->hasWeakLinkage() || DF->hasLinkOnceLinkage()) {
639 // At this point we know that SF has LinkOnce or External linkage.
640 ValueMap.insert(std::make_pair(SF, DF));
641 if (!SF->hasLinkOnceLinkage()) // Don't inherit linkonce linkage
642 DF->setLinkage(SF->getLinkage());
644 } else if (SF->getLinkage() != DF->getLinkage()) {
645 return Error(Err, "Functions named '" + SF->getName() +
646 "' have different linkage specifiers!");
647 } else if (SF->hasExternalLinkage()) {
648 // The function is defined in both modules!!
649 return Error(Err, "Function '" +
650 ToStr(SF->getFunctionType(), Src) + "':\"" +
651 SF->getName() + "\" - Function is already defined!");
653 assert(0 && "Unknown linkage configuration found!");
659 // LinkFunctionBody - Copy the source function over into the dest function and
660 // fix up references to values. At this point we know that Dest is an external
661 // function, and that Src is not.
663 static bool LinkFunctionBody(Function *Dest, Function *Src,
664 std::map<const Value*, Value*> &GlobalMap,
666 assert(Src && Dest && Dest->isExternal() && !Src->isExternal());
668 // Go through and convert function arguments over, remembering the mapping.
669 Function::aiterator DI = Dest->abegin();
670 for (Function::aiterator I = Src->abegin(), E = Src->aend();
672 DI->setName(I->getName()); // Copy the name information over...
674 // Add a mapping to our local map
675 GlobalMap.insert(std::make_pair(I, DI));
678 // Splice the body of the source function into the dest function.
679 Dest->getBasicBlockList().splice(Dest->end(), Src->getBasicBlockList());
681 // At this point, all of the instructions and values of the function are now
682 // copied over. The only problem is that they are still referencing values in
683 // the Source function as operands. Loop through all of the operands of the
684 // functions and patch them up to point to the local versions...
686 for (Function::iterator BB = Dest->begin(), BE = Dest->end(); BB != BE; ++BB)
687 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
688 for (Instruction::op_iterator OI = I->op_begin(), OE = I->op_end();
690 if (!isa<Instruction>(*OI) && !isa<BasicBlock>(*OI))
691 *OI = RemapOperand(*OI, GlobalMap);
693 // There is no need to map the arguments anymore.
694 for (Function::aiterator I = Src->abegin(), E = Src->aend();
702 // LinkFunctionBodies - Link in the function bodies that are defined in the
703 // source module into the DestModule. This consists basically of copying the
704 // function over and fixing up references to values.
706 static bool LinkFunctionBodies(Module *Dest, Module *Src,
707 std::map<const Value*, Value*> &ValueMap,
710 // Loop over all of the functions in the src module, mapping them over as we
713 for (Module::iterator SF = Src->begin(), E = Src->end(); SF != E; ++SF) {
714 if (!SF->isExternal()) { // No body if function is external
715 Function *DF = cast<Function>(ValueMap[SF]); // Destination function
717 // DF not external SF external?
718 if (DF->isExternal()) {
719 // Only provide the function body if there isn't one already.
720 if (LinkFunctionBody(DF, SF, ValueMap, Err))
728 // LinkAppendingVars - If there were any appending global variables, link them
729 // together now. Return true on error.
731 static bool LinkAppendingVars(Module *M,
732 std::multimap<std::string, GlobalVariable *> &AppendingVars,
733 std::string *ErrorMsg) {
734 if (AppendingVars.empty()) return false; // Nothing to do.
736 // Loop over the multimap of appending vars, processing any variables with the
737 // same name, forming a new appending global variable with both of the
738 // initializers merged together, then rewrite references to the old variables
741 std::vector<Constant*> Inits;
742 while (AppendingVars.size() > 1) {
743 // Get the first two elements in the map...
744 std::multimap<std::string,
745 GlobalVariable*>::iterator Second = AppendingVars.begin(), First=Second++;
747 // If the first two elements are for different names, there is no pair...
748 // Otherwise there is a pair, so link them together...
749 if (First->first == Second->first) {
750 GlobalVariable *G1 = First->second, *G2 = Second->second;
751 const ArrayType *T1 = cast<ArrayType>(G1->getType()->getElementType());
752 const ArrayType *T2 = cast<ArrayType>(G2->getType()->getElementType());
754 // Check to see that they two arrays agree on type...
755 if (T1->getElementType() != T2->getElementType())
756 return Error(ErrorMsg,
757 "Appending variables with different element types need to be linked!");
758 if (G1->isConstant() != G2->isConstant())
759 return Error(ErrorMsg,
760 "Appending variables linked with different const'ness!");
762 unsigned NewSize = T1->getNumElements() + T2->getNumElements();
763 ArrayType *NewType = ArrayType::get(T1->getElementType(), NewSize);
765 // Create the new global variable...
767 new GlobalVariable(NewType, G1->isConstant(), G1->getLinkage(),
768 /*init*/0, First->first, M);
770 // Merge the initializer...
771 Inits.reserve(NewSize);
772 if (ConstantArray *I = dyn_cast<ConstantArray>(G1->getInitializer())) {
773 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i)
774 Inits.push_back(I->getOperand(i));
776 assert(isa<ConstantAggregateZero>(G1->getInitializer()));
777 Constant *CV = Constant::getNullValue(T1->getElementType());
778 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i)
781 if (ConstantArray *I = dyn_cast<ConstantArray>(G2->getInitializer())) {
782 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i)
783 Inits.push_back(I->getOperand(i));
785 assert(isa<ConstantAggregateZero>(G2->getInitializer()));
786 Constant *CV = Constant::getNullValue(T2->getElementType());
787 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i)
790 NG->setInitializer(ConstantArray::get(NewType, Inits));
793 // Replace any uses of the two global variables with uses of the new
796 // FIXME: This should rewrite simple/straight-forward uses such as
797 // getelementptr instructions to not use the Cast!
798 G1->replaceAllUsesWith(ConstantExpr::getCast(NG, G1->getType()));
799 G2->replaceAllUsesWith(ConstantExpr::getCast(NG, G2->getType()));
801 // Remove the two globals from the module now...
802 M->getGlobalList().erase(G1);
803 M->getGlobalList().erase(G2);
805 // Put the new global into the AppendingVars map so that we can handle
806 // linking of more than two vars...
809 AppendingVars.erase(First);
816 // LinkModules - This function links two modules together, with the resulting
817 // left module modified to be the composite of the two input modules. If an
818 // error occurs, true is returned and ErrorMsg (if not null) is set to indicate
819 // the problem. Upon failure, the Dest module could be in a modified state, and
820 // shouldn't be relied on to be consistent.
821 bool llvm::LinkModules(Module *Dest, Module *Src, std::string *ErrorMsg) {
822 assert(Dest != 0 && "Invalid Destination module");
823 assert(Src != 0 && "Invalid Source Module");
825 if (Dest->getEndianness() == Module::AnyEndianness)
826 Dest->setEndianness(Src->getEndianness());
827 if (Dest->getPointerSize() == Module::AnyPointerSize)
828 Dest->setPointerSize(Src->getPointerSize());
830 if (Src->getEndianness() != Module::AnyEndianness &&
831 Dest->getEndianness() != Src->getEndianness())
832 std::cerr << "WARNING: Linking two modules of different endianness!\n";
833 if (Src->getPointerSize() != Module::AnyPointerSize &&
834 Dest->getPointerSize() != Src->getPointerSize())
835 std::cerr << "WARNING: Linking two modules of different pointer size!\n";
837 // Update the destination module's dependent libraries list with the libraries
838 // from the source module. There's no opportunity for duplicates here as the
839 // Module ensures that duplicate insertions are discarded.
840 Module::lib_iterator SI = Src->lib_begin();
841 Module::lib_iterator SE = Src->lib_end();
843 Dest->addLibrary(*SI);
847 // LinkTypes - Go through the symbol table of the Src module and see if any
848 // types are named in the src module that are not named in the Dst module.
849 // Make sure there are no type name conflicts.
851 if (LinkTypes(Dest, Src, ErrorMsg)) return true;
853 // ValueMap - Mapping of values from what they used to be in Src, to what they
856 std::map<const Value*, Value*> ValueMap;
858 // AppendingVars - Keep track of global variables in the destination module
859 // with appending linkage. After the module is linked together, they are
860 // appended and the module is rewritten.
862 std::multimap<std::string, GlobalVariable *> AppendingVars;
864 // GlobalsByName - The LLVM SymbolTable class fights our best efforts at
865 // linking by separating globals by type. Until PR411 is fixed, we replicate
866 // it's functionality here.
867 std::map<std::string, GlobalValue*> GlobalsByName;
869 for (Module::giterator I = Dest->gbegin(), E = Dest->gend(); I != E; ++I) {
870 // Add all of the appending globals already in the Dest module to
872 if (I->hasAppendingLinkage())
873 AppendingVars.insert(std::make_pair(I->getName(), I));
875 // Keep track of all globals by name.
876 if (!I->hasInternalLinkage() && I->hasName())
877 GlobalsByName[I->getName()] = I;
880 // Keep track of all globals by name.
881 for (Module::iterator I = Dest->begin(), E = Dest->end(); I != E; ++I)
882 if (!I->hasInternalLinkage() && I->hasName())
883 GlobalsByName[I->getName()] = I;
885 // Insert all of the globals in src into the Dest module... without linking
886 // initializers (which could refer to functions not yet mapped over).
888 if (LinkGlobals(Dest, Src, ValueMap, AppendingVars, GlobalsByName, ErrorMsg))
891 // Link the functions together between the two modules, without doing function
892 // bodies... this just adds external function prototypes to the Dest
893 // function... We do this so that when we begin processing function bodies,
894 // all of the global values that may be referenced are available in our
897 if (LinkFunctionProtos(Dest, Src, ValueMap, GlobalsByName, ErrorMsg))
900 // Update the initializers in the Dest module now that all globals that may
901 // be referenced are in Dest.
903 if (LinkGlobalInits(Dest, Src, ValueMap, ErrorMsg)) return true;
905 // Link in the function bodies that are defined in the source module into the
906 // DestModule. This consists basically of copying the function over and
907 // fixing up references to values.
909 if (LinkFunctionBodies(Dest, Src, ValueMap, ErrorMsg)) return true;
911 // If there were any appending global variables, link them together now.
913 if (LinkAppendingVars(Dest, AppendingVars, ErrorMsg)) return true;
915 // If the source library's module id is in the dependent library list of the
916 // destination library, remove it since that module is now linked in.
918 modId.setFile(Src->getModuleIdentifier());
919 if (!modId.isEmpty())
920 Dest->removeLibrary(modId.getBasename());