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...
33 static inline bool Error(std::string *E, const std::string &Message) {
38 // ToStr - Simple wrapper function to convert a type to a string.
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
94 static bool RecursiveResolveTypesI(const PATypeHolder &DestTy,
95 const PATypeHolder &SrcTy,
96 SymbolTable *DestST, const std::string &Name,
97 std::vector<std::pair<PATypeHolder, PATypeHolder> > &Pointers) {
98 const Type *SrcTyT = SrcTy.get();
99 const Type *DestTyT = DestTy.get();
100 if (DestTyT == SrcTyT) return false; // If already equal, noop
102 // If we found our opaque type, resolve it now!
103 if (isa<OpaqueType>(DestTyT) || isa<OpaqueType>(SrcTyT))
104 return ResolveTypes(DestTyT, SrcTyT, DestST, Name);
106 // Two types cannot be resolved together if they are of different primitive
107 // type. For example, we cannot resolve an int to a float.
108 if (DestTyT->getTypeID() != SrcTyT->getTypeID()) return true;
110 // Otherwise, resolve the used type used by this derived type...
111 switch (DestTyT->getTypeID()) {
112 case Type::FunctionTyID: {
113 if (cast<FunctionType>(DestTyT)->isVarArg() !=
114 cast<FunctionType>(SrcTyT)->isVarArg() ||
115 cast<FunctionType>(DestTyT)->getNumContainedTypes() !=
116 cast<FunctionType>(SrcTyT)->getNumContainedTypes())
118 for (unsigned i = 0, e = getFT(DestTy)->getNumContainedTypes(); i != e; ++i)
119 if (RecursiveResolveTypesI(getFT(DestTy)->getContainedType(i),
120 getFT(SrcTy)->getContainedType(i), DestST, "",
125 case Type::StructTyID: {
126 if (getST(DestTy)->getNumContainedTypes() !=
127 getST(SrcTy)->getNumContainedTypes()) return 1;
128 for (unsigned i = 0, e = getST(DestTy)->getNumContainedTypes(); i != e; ++i)
129 if (RecursiveResolveTypesI(getST(DestTy)->getContainedType(i),
130 getST(SrcTy)->getContainedType(i), DestST, "",
135 case Type::ArrayTyID: {
136 const ArrayType *DAT = cast<ArrayType>(DestTy.get());
137 const ArrayType *SAT = cast<ArrayType>(SrcTy.get());
138 if (DAT->getNumElements() != SAT->getNumElements()) return true;
139 return RecursiveResolveTypesI(DAT->getElementType(), SAT->getElementType(),
140 DestST, "", Pointers);
142 case Type::PointerTyID: {
143 // If this is a pointer type, check to see if we have already seen it. If
144 // so, we are in a recursive branch. Cut off the search now. We cannot use
145 // an associative container for this search, because the type pointers (keys
146 // in the container) change whenever types get resolved...
147 for (unsigned i = 0, e = Pointers.size(); i != e; ++i)
148 if (Pointers[i].first == DestTy)
149 return Pointers[i].second != SrcTy;
151 // Otherwise, add the current pointers to the vector to stop recursion on
153 Pointers.push_back(std::make_pair(DestTyT, SrcTyT));
155 RecursiveResolveTypesI(cast<PointerType>(DestTy.get())->getElementType(),
156 cast<PointerType>(SrcTy.get())->getElementType(),
157 DestST, "", Pointers);
161 default: assert(0 && "Unexpected type!"); return true;
165 static bool RecursiveResolveTypes(const PATypeHolder &DestTy,
166 const PATypeHolder &SrcTy,
167 SymbolTable *DestST, const std::string &Name){
168 std::vector<std::pair<PATypeHolder, PATypeHolder> > PointerTypes;
169 return RecursiveResolveTypesI(DestTy, SrcTy, DestST, Name, PointerTypes);
173 // LinkTypes - Go through the symbol table of the Src module and see if any
174 // types are named in the src module that are not named in the Dst module.
175 // Make sure there are no type name conflicts.
176 static bool LinkTypes(Module *Dest, const Module *Src, std::string *Err) {
177 SymbolTable *DestST = &Dest->getSymbolTable();
178 const SymbolTable *SrcST = &Src->getSymbolTable();
180 // Look for a type plane for Type's...
181 SymbolTable::type_const_iterator TI = SrcST->type_begin();
182 SymbolTable::type_const_iterator TE = SrcST->type_end();
183 if (TI == TE) return false; // No named types, do nothing.
185 // Some types cannot be resolved immediately because they depend on other
186 // types being resolved to each other first. This contains a list of types we
187 // are waiting to recheck.
188 std::vector<std::string> DelayedTypesToResolve;
190 for ( ; TI != TE; ++TI ) {
191 const std::string &Name = TI->first;
192 const Type *RHS = TI->second;
194 // Check to see if this type name is already in the dest module...
195 Type *Entry = DestST->lookupType(Name);
197 if (ResolveTypes(Entry, RHS, DestST, Name)) {
198 // They look different, save the types 'till later to resolve.
199 DelayedTypesToResolve.push_back(Name);
203 // Iteratively resolve types while we can...
204 while (!DelayedTypesToResolve.empty()) {
205 // Loop over all of the types, attempting to resolve them if possible...
206 unsigned OldSize = DelayedTypesToResolve.size();
208 // Try direct resolution by name...
209 for (unsigned i = 0; i != DelayedTypesToResolve.size(); ++i) {
210 const std::string &Name = DelayedTypesToResolve[i];
211 Type *T1 = SrcST->lookupType(Name);
212 Type *T2 = DestST->lookupType(Name);
213 if (!ResolveTypes(T2, T1, DestST, Name)) {
214 // We are making progress!
215 DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i);
220 // Did we not eliminate any types?
221 if (DelayedTypesToResolve.size() == OldSize) {
222 // Attempt to resolve subelements of types. This allows us to merge these
223 // two types: { int* } and { opaque* }
224 for (unsigned i = 0, e = DelayedTypesToResolve.size(); i != e; ++i) {
225 const std::string &Name = DelayedTypesToResolve[i];
226 PATypeHolder T1(SrcST->lookupType(Name));
227 PATypeHolder T2(DestST->lookupType(Name));
229 if (!RecursiveResolveTypes(T2, T1, DestST, Name)) {
230 // We are making progress!
231 DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i);
233 // Go back to the main loop, perhaps we can resolve directly by name
239 // If we STILL cannot resolve the types, then there is something wrong.
240 if (DelayedTypesToResolve.size() == OldSize) {
241 // Remove the symbol name from the destination.
242 DelayedTypesToResolve.pop_back();
251 static void PrintMap(const std::map<const Value*, Value*> &M) {
252 for (std::map<const Value*, Value*>::const_iterator I = M.begin(), E =M.end();
254 std::cerr << " Fr: " << (void*)I->first << " ";
256 std::cerr << " To: " << (void*)I->second << " ";
263 // RemapOperand - Use ValueMap to convert references from one module to another.
264 // This is somewhat sophisticated in that it can automatically handle constant
265 // references correctly as well.
266 static Value *RemapOperand(const Value *In,
267 std::map<const Value*, Value*> &ValueMap) {
268 std::map<const Value*,Value*>::const_iterator I = ValueMap.find(In);
269 if (I != ValueMap.end()) return I->second;
271 // Check to see if it's a constant that we are interesting in transforming.
273 if (const Constant *CPV = dyn_cast<Constant>(In)) {
274 if ((!isa<DerivedType>(CPV->getType()) && !isa<ConstantExpr>(CPV)) ||
275 isa<ConstantAggregateZero>(CPV))
276 return const_cast<Constant*>(CPV); // Simple constants stay identical.
278 if (const ConstantArray *CPA = dyn_cast<ConstantArray>(CPV)) {
279 std::vector<Constant*> Operands(CPA->getNumOperands());
280 for (unsigned i = 0, e = CPA->getNumOperands(); i != e; ++i)
281 Operands[i] =cast<Constant>(RemapOperand(CPA->getOperand(i), ValueMap));
282 Result = ConstantArray::get(cast<ArrayType>(CPA->getType()), Operands);
283 } else if (const ConstantStruct *CPS = dyn_cast<ConstantStruct>(CPV)) {
284 std::vector<Constant*> Operands(CPS->getNumOperands());
285 for (unsigned i = 0, e = CPS->getNumOperands(); i != e; ++i)
286 Operands[i] =cast<Constant>(RemapOperand(CPS->getOperand(i), ValueMap));
287 Result = ConstantStruct::get(cast<StructType>(CPS->getType()), Operands);
288 } else if (isa<ConstantPointerNull>(CPV) || isa<UndefValue>(CPV)) {
289 Result = const_cast<Constant*>(CPV);
290 } else if (isa<GlobalValue>(CPV)) {
291 Result = cast<Constant>(RemapOperand(CPV, ValueMap));
292 } else if (const ConstantPacked *CP = dyn_cast<ConstantPacked>(CPV)) {
293 std::vector<Constant*> Operands(CP->getNumOperands());
294 for (unsigned i = 0, e = CP->getNumOperands(); i != e; ++i)
295 Operands[i] = cast<Constant>(RemapOperand(CP->getOperand(i), ValueMap));
296 Result = ConstantPacked::get(Operands);
297 } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CPV)) {
298 if (CE->getOpcode() == Instruction::GetElementPtr) {
299 Value *Ptr = RemapOperand(CE->getOperand(0), ValueMap);
300 std::vector<Constant*> Indices;
301 Indices.reserve(CE->getNumOperands()-1);
302 for (unsigned i = 1, e = CE->getNumOperands(); i != e; ++i)
303 Indices.push_back(cast<Constant>(RemapOperand(CE->getOperand(i),
306 Result = ConstantExpr::getGetElementPtr(cast<Constant>(Ptr), Indices);
307 } else if (CE->getOpcode() == Instruction::ExtractElement) {
308 Value *Ptr = RemapOperand(CE->getOperand(0), ValueMap);
309 Value *Idx = RemapOperand(CE->getOperand(1), ValueMap);
310 Result = ConstantExpr::getExtractElement(cast<Constant>(Ptr),
311 cast<Constant>(Idx));
312 } else if (CE->getOpcode() == Instruction::InsertElement) {
313 Value *Ptr = RemapOperand(CE->getOperand(0), ValueMap);
314 Value *Elt = RemapOperand(CE->getOperand(1), ValueMap);
315 Value *Idx = RemapOperand(CE->getOperand(2), ValueMap);
316 Result = ConstantExpr::getInsertElement(cast<Constant>(Ptr),
318 cast<Constant>(Idx));
319 } else if (CE->getOpcode() == Instruction::ShuffleVector) {
320 Value *V1 = RemapOperand(CE->getOperand(0), ValueMap);
321 Value *V2 = RemapOperand(CE->getOperand(1), ValueMap);
322 Result = ConstantExpr::getShuffleVector(cast<Constant>(V1),
324 cast<Constant>(CE->getOperand(2)));
325 } else if (CE->getNumOperands() == 1) {
327 assert(CE->getOpcode() == Instruction::Cast);
328 Value *V = RemapOperand(CE->getOperand(0), ValueMap);
329 Result = ConstantExpr::getCast(cast<Constant>(V), CE->getType());
330 } else if (CE->getNumOperands() == 3) {
331 // Select instruction
332 assert(CE->getOpcode() == Instruction::Select);
333 Value *V1 = RemapOperand(CE->getOperand(0), ValueMap);
334 Value *V2 = RemapOperand(CE->getOperand(1), ValueMap);
335 Value *V3 = RemapOperand(CE->getOperand(2), ValueMap);
336 Result = ConstantExpr::getSelect(cast<Constant>(V1), cast<Constant>(V2),
338 } else if (CE->getNumOperands() == 2) {
339 // Binary operator...
340 Value *V1 = RemapOperand(CE->getOperand(0), ValueMap);
341 Value *V2 = RemapOperand(CE->getOperand(1), ValueMap);
343 Result = ConstantExpr::get(CE->getOpcode(), cast<Constant>(V1),
346 assert(0 && "Unknown constant expr type!");
350 assert(0 && "Unknown type of derived type constant value!");
352 } else if (isa<InlineAsm>(In)) {
353 Result = const_cast<Value*>(In);
356 // Cache the mapping in our local map structure...
358 ValueMap.insert(std::make_pair(In, Result));
363 std::cerr << "LinkModules ValueMap: \n";
366 std::cerr << "Couldn't remap value: " << (void*)In << " " << *In << "\n";
367 assert(0 && "Couldn't remap value!");
371 /// ForceRenaming - The LLVM SymbolTable class autorenames globals that conflict
372 /// in the symbol table. This is good for all clients except for us. Go
373 /// through the trouble to force this back.
374 static void ForceRenaming(GlobalValue *GV, const std::string &Name) {
375 assert(GV->getName() != Name && "Can't force rename to self");
376 SymbolTable &ST = GV->getParent()->getSymbolTable();
378 // If there is a conflict, rename the conflict.
379 Value *ConflictVal = ST.lookup(GV->getType(), Name);
380 assert(ConflictVal&&"Why do we have to force rename if there is no conflic?");
381 GlobalValue *ConflictGV = cast<GlobalValue>(ConflictVal);
382 assert(ConflictGV->hasInternalLinkage() &&
383 "Not conflicting with a static global, should link instead!");
385 ConflictGV->setName(""); // Eliminate the conflict
386 GV->setName(Name); // Force the name back
387 ConflictGV->setName(Name); // This will cause ConflictGV to get renamed
388 assert(GV->getName() == Name && ConflictGV->getName() != Name &&
389 "ForceRenaming didn't work");
392 /// GetLinkageResult - This analyzes the two global values and determines what
393 /// the result will look like in the destination module. In particular, it
394 /// computes the resultant linkage type, computes whether the global in the
395 /// source should be copied over to the destination (replacing the existing
396 /// one), and computes whether this linkage is an error or not.
397 static bool GetLinkageResult(GlobalValue *Dest, GlobalValue *Src,
398 GlobalValue::LinkageTypes <, bool &LinkFromSrc,
400 assert((!Dest || !Src->hasInternalLinkage()) &&
401 "If Src has internal linkage, Dest shouldn't be set!");
403 // Linking something to nothing.
405 LT = Src->getLinkage();
406 } else if (Src->isExternal()) {
407 // If Src is external or if both Src & Drc are external.. Just link the
408 // external globals, we aren't adding anything.
410 LT = Dest->getLinkage();
411 } else if (Dest->isExternal()) {
412 // If Dest is external but Src is not:
414 LT = Src->getLinkage();
415 } else if (Src->hasAppendingLinkage() || Dest->hasAppendingLinkage()) {
416 if (Src->getLinkage() != Dest->getLinkage())
417 return Error(Err, "Linking globals named '" + Src->getName() +
418 "': can only link appending global with another appending global!");
419 LinkFromSrc = true; // Special cased.
420 LT = Src->getLinkage();
421 } else if (Src->hasWeakLinkage() || Src->hasLinkOnceLinkage()) {
422 // At this point we know that Dest has LinkOnce, External or Weak linkage.
423 if (Dest->hasLinkOnceLinkage() && Src->hasWeakLinkage()) {
425 LT = Src->getLinkage();
428 LT = Dest->getLinkage();
430 } else if (Dest->hasWeakLinkage() || Dest->hasLinkOnceLinkage()) {
431 // At this point we know that Src has External linkage.
433 LT = GlobalValue::ExternalLinkage;
435 assert(Dest->hasExternalLinkage() && Src->hasExternalLinkage() &&
436 "Unexpected linkage type!");
437 return Error(Err, "Linking globals named '" + Src->getName() +
438 "': symbol multiply defined!");
443 // LinkGlobals - Loop through the global variables in the src module and merge
444 // them into the dest module.
445 static bool LinkGlobals(Module *Dest, Module *Src,
446 std::map<const Value*, Value*> &ValueMap,
447 std::multimap<std::string, GlobalVariable *> &AppendingVars,
448 std::map<std::string, GlobalValue*> &GlobalsByName,
450 // We will need a module level symbol table if the src module has a module
451 // level symbol table...
452 SymbolTable *ST = (SymbolTable*)&Dest->getSymbolTable();
454 // Loop over all of the globals in the src module, mapping them over as we go
455 for (Module::global_iterator I = Src->global_begin(), E = Src->global_end(); I != E; ++I) {
456 GlobalVariable *SGV = I;
457 GlobalVariable *DGV = 0;
458 // Check to see if may have to link the global.
459 if (SGV->hasName() && !SGV->hasInternalLinkage())
460 if (!(DGV = Dest->getGlobalVariable(SGV->getName(),
461 SGV->getType()->getElementType()))) {
462 std::map<std::string, GlobalValue*>::iterator EGV =
463 GlobalsByName.find(SGV->getName());
464 if (EGV != GlobalsByName.end())
465 DGV = dyn_cast<GlobalVariable>(EGV->second);
467 // If types don't agree due to opaque types, try to resolve them.
468 RecursiveResolveTypes(SGV->getType(), DGV->getType(),ST, "");
471 if (DGV && DGV->hasInternalLinkage())
474 assert(SGV->hasInitializer() || SGV->hasExternalLinkage() &&
475 "Global must either be external or have an initializer!");
477 GlobalValue::LinkageTypes NewLinkage;
479 if (GetLinkageResult(DGV, SGV, NewLinkage, LinkFromSrc, Err))
483 // No linking to be performed, simply create an identical version of the
484 // symbol over in the dest module... the initializer will be filled in
485 // later by LinkGlobalInits...
486 GlobalVariable *NewDGV =
487 new GlobalVariable(SGV->getType()->getElementType(),
488 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
489 SGV->getName(), Dest);
491 // If the LLVM runtime renamed the global, but it is an externally visible
492 // symbol, DGV must be an existing global with internal linkage. Rename
494 if (NewDGV->getName() != SGV->getName() && !NewDGV->hasInternalLinkage())
495 ForceRenaming(NewDGV, SGV->getName());
497 // Make sure to remember this mapping...
498 ValueMap.insert(std::make_pair(SGV, NewDGV));
499 if (SGV->hasAppendingLinkage())
500 // Keep track that this is an appending variable...
501 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV));
502 } else if (DGV->hasAppendingLinkage()) {
503 // No linking is performed yet. Just insert a new copy of the global, and
504 // keep track of the fact that it is an appending variable in the
505 // AppendingVars map. The name is cleared out so that no linkage is
507 GlobalVariable *NewDGV =
508 new GlobalVariable(SGV->getType()->getElementType(),
509 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
512 // Make sure to remember this mapping...
513 ValueMap.insert(std::make_pair(SGV, NewDGV));
515 // Keep track that this is an appending variable...
516 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV));
518 // Otherwise, perform the mapping as instructed by GetLinkageResult. If
519 // the types don't match, and if we are to link from the source, nuke DGV
520 // and create a new one of the appropriate type.
521 if (SGV->getType() != DGV->getType() && LinkFromSrc) {
522 GlobalVariable *NewDGV =
523 new GlobalVariable(SGV->getType()->getElementType(),
524 DGV->isConstant(), DGV->getLinkage());
525 Dest->getGlobalList().insert(DGV, NewDGV);
526 DGV->replaceAllUsesWith(ConstantExpr::getCast(NewDGV, DGV->getType()));
527 DGV->eraseFromParent();
528 NewDGV->setName(SGV->getName());
532 DGV->setLinkage(NewLinkage);
535 // Inherit const as appropriate
536 DGV->setConstant(SGV->isConstant());
537 DGV->setInitializer(0);
539 if (SGV->isConstant() && !DGV->isConstant()) {
540 if (DGV->isExternal())
541 DGV->setConstant(true);
543 SGV->setLinkage(GlobalValue::ExternalLinkage);
544 SGV->setInitializer(0);
547 ValueMap.insert(std::make_pair(SGV,
548 ConstantExpr::getCast(DGV,
556 // LinkGlobalInits - Update the initializers in the Dest module now that all
557 // globals that may be referenced are in Dest.
558 static bool LinkGlobalInits(Module *Dest, const Module *Src,
559 std::map<const Value*, Value*> &ValueMap,
562 // Loop over all of the globals in the src module, mapping them over as we go
563 for (Module::const_global_iterator I = Src->global_begin(), E = Src->global_end(); I != E; ++I){
564 const GlobalVariable *SGV = I;
566 if (SGV->hasInitializer()) { // Only process initialized GV's
567 // Figure out what the initializer looks like in the dest module...
569 cast<Constant>(RemapOperand(SGV->getInitializer(), ValueMap));
571 GlobalVariable *DGV = cast<GlobalVariable>(ValueMap[SGV]);
572 if (DGV->hasInitializer()) {
573 if (SGV->hasExternalLinkage()) {
574 if (DGV->getInitializer() != SInit)
575 return Error(Err, "Global Variable Collision on '" +
576 ToStr(SGV->getType(), Src) +"':%"+SGV->getName()+
577 " - Global variables have different initializers");
578 } else if (DGV->hasLinkOnceLinkage() || DGV->hasWeakLinkage()) {
579 // Nothing is required, mapped values will take the new global
581 } else if (SGV->hasLinkOnceLinkage() || SGV->hasWeakLinkage()) {
582 // Nothing is required, mapped values will take the new global
584 } else if (DGV->hasAppendingLinkage()) {
585 assert(0 && "Appending linkage unimplemented!");
587 assert(0 && "Unknown linkage!");
590 // Copy the initializer over now...
591 DGV->setInitializer(SInit);
598 // LinkFunctionProtos - Link the functions together between the two modules,
599 // without doing function bodies... this just adds external function prototypes
600 // to the Dest function...
602 static bool LinkFunctionProtos(Module *Dest, const Module *Src,
603 std::map<const Value*, Value*> &ValueMap,
604 std::map<std::string, GlobalValue*> &GlobalsByName,
606 SymbolTable *ST = (SymbolTable*)&Dest->getSymbolTable();
608 // Loop over all of the functions in the src module, mapping them over as we
610 for (Module::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) {
611 const Function *SF = I; // SrcFunction
613 if (SF->hasName() && !SF->hasInternalLinkage()) {
614 // Check to see if may have to link the function.
615 if (!(DF = Dest->getFunction(SF->getName(), SF->getFunctionType()))) {
616 std::map<std::string, GlobalValue*>::iterator EF =
617 GlobalsByName.find(SF->getName());
618 if (EF != GlobalsByName.end())
619 DF = dyn_cast<Function>(EF->second);
620 if (DF && RecursiveResolveTypes(SF->getType(), DF->getType(), ST, ""))
621 DF = 0; // FIXME: gross.
625 if (!DF || SF->hasInternalLinkage() || DF->hasInternalLinkage()) {
626 // Function does not already exist, simply insert an function signature
627 // identical to SF into the dest module...
628 Function *NewDF = new Function(SF->getFunctionType(), SF->getLinkage(),
629 SF->getName(), Dest);
630 NewDF->setCallingConv(SF->getCallingConv());
632 // If the LLVM runtime renamed the function, but it is an externally
633 // visible symbol, DF must be an existing function with internal linkage.
635 if (NewDF->getName() != SF->getName() && !NewDF->hasInternalLinkage())
636 ForceRenaming(NewDF, SF->getName());
638 // ... and remember this mapping...
639 ValueMap.insert(std::make_pair(SF, NewDF));
640 } else if (SF->isExternal()) {
641 // If SF is external or if both SF & DF are external.. Just link the
642 // external functions, we aren't adding anything.
643 ValueMap.insert(std::make_pair(SF, DF));
644 } else if (DF->isExternal()) { // If DF is external but SF is not...
645 // Link the external functions, update linkage qualifiers
646 ValueMap.insert(std::make_pair(SF, DF));
647 DF->setLinkage(SF->getLinkage());
649 } else if (SF->hasWeakLinkage() || SF->hasLinkOnceLinkage()) {
650 // At this point we know that DF has LinkOnce, Weak, or External linkage.
651 ValueMap.insert(std::make_pair(SF, DF));
653 // Linkonce+Weak = Weak
654 if (DF->hasLinkOnceLinkage() && SF->hasWeakLinkage())
655 DF->setLinkage(SF->getLinkage());
657 } else if (DF->hasWeakLinkage() || DF->hasLinkOnceLinkage()) {
658 // At this point we know that SF has LinkOnce or External linkage.
659 ValueMap.insert(std::make_pair(SF, DF));
660 if (!SF->hasLinkOnceLinkage()) // Don't inherit linkonce linkage
661 DF->setLinkage(SF->getLinkage());
663 } else if (SF->getLinkage() != DF->getLinkage()) {
664 return Error(Err, "Functions named '" + SF->getName() +
665 "' have different linkage specifiers!");
666 } else if (SF->hasExternalLinkage()) {
667 // The function is defined in both modules!!
668 return Error(Err, "Function '" +
669 ToStr(SF->getFunctionType(), Src) + "':\"" +
670 SF->getName() + "\" - Function is already defined!");
672 assert(0 && "Unknown linkage configuration found!");
678 // LinkFunctionBody - Copy the source function over into the dest function and
679 // fix up references to values. At this point we know that Dest is an external
680 // function, and that Src is not.
681 static bool LinkFunctionBody(Function *Dest, Function *Src,
682 std::map<const Value*, Value*> &GlobalMap,
684 assert(Src && Dest && Dest->isExternal() && !Src->isExternal());
686 // Go through and convert function arguments over, remembering the mapping.
687 Function::arg_iterator DI = Dest->arg_begin();
688 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end();
690 DI->setName(I->getName()); // Copy the name information over...
692 // Add a mapping to our local map
693 GlobalMap.insert(std::make_pair(I, DI));
696 // Splice the body of the source function into the dest function.
697 Dest->getBasicBlockList().splice(Dest->end(), Src->getBasicBlockList());
699 // At this point, all of the instructions and values of the function are now
700 // copied over. The only problem is that they are still referencing values in
701 // the Source function as operands. Loop through all of the operands of the
702 // functions and patch them up to point to the local versions...
704 for (Function::iterator BB = Dest->begin(), BE = Dest->end(); BB != BE; ++BB)
705 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
706 for (Instruction::op_iterator OI = I->op_begin(), OE = I->op_end();
708 if (!isa<Instruction>(*OI) && !isa<BasicBlock>(*OI))
709 *OI = RemapOperand(*OI, GlobalMap);
711 // There is no need to map the arguments anymore.
712 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end(); I != E; ++I)
719 // LinkFunctionBodies - Link in the function bodies that are defined in the
720 // source module into the DestModule. This consists basically of copying the
721 // function over and fixing up references to values.
722 static bool LinkFunctionBodies(Module *Dest, Module *Src,
723 std::map<const Value*, Value*> &ValueMap,
726 // Loop over all of the functions in the src module, mapping them over as we
728 for (Module::iterator SF = Src->begin(), E = Src->end(); SF != E; ++SF) {
729 if (!SF->isExternal()) { // No body if function is external
730 Function *DF = cast<Function>(ValueMap[SF]); // Destination function
732 // DF not external SF external?
733 if (DF->isExternal()) {
734 // Only provide the function body if there isn't one already.
735 if (LinkFunctionBody(DF, SF, ValueMap, Err))
743 // LinkAppendingVars - If there were any appending global variables, link them
744 // together now. Return true on error.
745 static bool LinkAppendingVars(Module *M,
746 std::multimap<std::string, GlobalVariable *> &AppendingVars,
747 std::string *ErrorMsg) {
748 if (AppendingVars.empty()) return false; // Nothing to do.
750 // Loop over the multimap of appending vars, processing any variables with the
751 // same name, forming a new appending global variable with both of the
752 // initializers merged together, then rewrite references to the old variables
754 std::vector<Constant*> Inits;
755 while (AppendingVars.size() > 1) {
756 // Get the first two elements in the map...
757 std::multimap<std::string,
758 GlobalVariable*>::iterator Second = AppendingVars.begin(), First=Second++;
760 // If the first two elements are for different names, there is no pair...
761 // Otherwise there is a pair, so link them together...
762 if (First->first == Second->first) {
763 GlobalVariable *G1 = First->second, *G2 = Second->second;
764 const ArrayType *T1 = cast<ArrayType>(G1->getType()->getElementType());
765 const ArrayType *T2 = cast<ArrayType>(G2->getType()->getElementType());
767 // Check to see that they two arrays agree on type...
768 if (T1->getElementType() != T2->getElementType())
769 return Error(ErrorMsg,
770 "Appending variables with different element types need to be linked!");
771 if (G1->isConstant() != G2->isConstant())
772 return Error(ErrorMsg,
773 "Appending variables linked with different const'ness!");
775 unsigned NewSize = T1->getNumElements() + T2->getNumElements();
776 ArrayType *NewType = ArrayType::get(T1->getElementType(), NewSize);
778 G1->setName(""); // Clear G1's name in case of a conflict!
780 // Create the new global variable...
782 new GlobalVariable(NewType, G1->isConstant(), G1->getLinkage(),
783 /*init*/0, First->first, M);
785 // Merge the initializer...
786 Inits.reserve(NewSize);
787 if (ConstantArray *I = dyn_cast<ConstantArray>(G1->getInitializer())) {
788 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i)
789 Inits.push_back(I->getOperand(i));
791 assert(isa<ConstantAggregateZero>(G1->getInitializer()));
792 Constant *CV = Constant::getNullValue(T1->getElementType());
793 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i)
796 if (ConstantArray *I = dyn_cast<ConstantArray>(G2->getInitializer())) {
797 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i)
798 Inits.push_back(I->getOperand(i));
800 assert(isa<ConstantAggregateZero>(G2->getInitializer()));
801 Constant *CV = Constant::getNullValue(T2->getElementType());
802 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i)
805 NG->setInitializer(ConstantArray::get(NewType, Inits));
808 // Replace any uses of the two global variables with uses of the new
811 // FIXME: This should rewrite simple/straight-forward uses such as
812 // getelementptr instructions to not use the Cast!
813 G1->replaceAllUsesWith(ConstantExpr::getCast(NG, G1->getType()));
814 G2->replaceAllUsesWith(ConstantExpr::getCast(NG, G2->getType()));
816 // Remove the two globals from the module now...
817 M->getGlobalList().erase(G1);
818 M->getGlobalList().erase(G2);
820 // Put the new global into the AppendingVars map so that we can handle
821 // linking of more than two vars...
824 AppendingVars.erase(First);
831 // LinkModules - This function links two modules together, with the resulting
832 // left module modified to be the composite of the two input modules. If an
833 // error occurs, true is returned and ErrorMsg (if not null) is set to indicate
834 // the problem. Upon failure, the Dest module could be in a modified state, and
835 // shouldn't be relied on to be consistent.
837 Linker::LinkModules(Module *Dest, Module *Src, std::string *ErrorMsg) {
838 assert(Dest != 0 && "Invalid Destination module");
839 assert(Src != 0 && "Invalid Source Module");
841 if (Dest->getEndianness() == Module::AnyEndianness)
842 Dest->setEndianness(Src->getEndianness());
843 if (Dest->getPointerSize() == Module::AnyPointerSize)
844 Dest->setPointerSize(Src->getPointerSize());
845 if (Dest->getTargetTriple().empty())
846 Dest->setTargetTriple(Src->getTargetTriple());
848 if (Src->getEndianness() != Module::AnyEndianness &&
849 Dest->getEndianness() != Src->getEndianness())
850 std::cerr << "WARNING: Linking two modules of different endianness!\n";
851 if (Src->getPointerSize() != Module::AnyPointerSize &&
852 Dest->getPointerSize() != Src->getPointerSize())
853 std::cerr << "WARNING: Linking two modules of different pointer size!\n";
854 if (!Src->getTargetTriple().empty() &&
855 Dest->getTargetTriple() != Src->getTargetTriple())
856 std::cerr << "WARNING: Linking two modules of different target triples!\n";
858 if (!Src->getModuleInlineAsm().empty()) {
859 if (Dest->getModuleInlineAsm().empty())
860 Dest->setModuleInlineAsm(Src->getModuleInlineAsm());
862 Dest->setModuleInlineAsm(Dest->getModuleInlineAsm()+"\n"+
863 Src->getModuleInlineAsm());
866 // Update the destination module's dependent libraries list with the libraries
867 // from the source module. There's no opportunity for duplicates here as the
868 // Module ensures that duplicate insertions are discarded.
869 Module::lib_iterator SI = Src->lib_begin();
870 Module::lib_iterator SE = Src->lib_end();
872 Dest->addLibrary(*SI);
876 // LinkTypes - Go through the symbol table of the Src module and see if any
877 // types are named in the src module that are not named in the Dst module.
878 // Make sure there are no type name conflicts.
879 if (LinkTypes(Dest, Src, ErrorMsg)) return true;
881 // ValueMap - Mapping of values from what they used to be in Src, to what they
883 std::map<const Value*, Value*> ValueMap;
885 // AppendingVars - Keep track of global variables in the destination module
886 // with appending linkage. After the module is linked together, they are
887 // appended and the module is rewritten.
888 std::multimap<std::string, GlobalVariable *> AppendingVars;
890 // GlobalsByName - The LLVM SymbolTable class fights our best efforts at
891 // linking by separating globals by type. Until PR411 is fixed, we replicate
892 // it's functionality here.
893 std::map<std::string, GlobalValue*> GlobalsByName;
895 for (Module::global_iterator I = Dest->global_begin(), E = Dest->global_end(); I != E; ++I) {
896 // Add all of the appending globals already in the Dest module to
898 if (I->hasAppendingLinkage())
899 AppendingVars.insert(std::make_pair(I->getName(), I));
901 // Keep track of all globals by name.
902 if (!I->hasInternalLinkage() && I->hasName())
903 GlobalsByName[I->getName()] = I;
906 // Keep track of all globals by name.
907 for (Module::iterator I = Dest->begin(), E = Dest->end(); I != E; ++I)
908 if (!I->hasInternalLinkage() && I->hasName())
909 GlobalsByName[I->getName()] = I;
911 // Insert all of the globals in src into the Dest module... without linking
912 // initializers (which could refer to functions not yet mapped over).
913 if (LinkGlobals(Dest, Src, ValueMap, AppendingVars, GlobalsByName, ErrorMsg))
916 // Link the functions together between the two modules, without doing function
917 // bodies... this just adds external function prototypes to the Dest
918 // function... We do this so that when we begin processing function bodies,
919 // all of the global values that may be referenced are available in our
921 if (LinkFunctionProtos(Dest, Src, ValueMap, GlobalsByName, ErrorMsg))
924 // Update the initializers in the Dest module now that all globals that may
925 // be referenced are in Dest.
926 if (LinkGlobalInits(Dest, Src, ValueMap, ErrorMsg)) return true;
928 // Link in the function bodies that are defined in the source module into the
929 // DestModule. This consists basically of copying the function over and
930 // fixing up references to values.
931 if (LinkFunctionBodies(Dest, Src, ValueMap, ErrorMsg)) return true;
933 // If there were any appending global variables, link them together now.
934 if (LinkAppendingVars(Dest, AppendingVars, ErrorMsg)) return true;
936 // If the source library's module id is in the dependent library list of the
937 // destination library, remove it since that module is now linked in.
939 modId.set(Src->getModuleIdentifier());
940 if (!modId.isEmpty())
941 Dest->removeLibrary(modId.getBasename());