1 //===- Linker.cpp - Module Linker Implementation --------------------------===//
3 // This file implements the LLVM module linker.
6 // * Merges global variables between the two modules
7 // * Uninit + Uninit = Init, Init + Uninit = Init, Init + Init = Error if !=
8 // * Merges functions between two modules
10 //===----------------------------------------------------------------------===//
12 #include "llvm/Transforms/Utils/Linker.h"
13 #include "llvm/Module.h"
14 #include "llvm/SymbolTable.h"
15 #include "llvm/DerivedTypes.h"
16 #include "llvm/iOther.h"
17 #include "llvm/Constants.h"
19 // Error - Simple wrapper function to conditionally assign to E and return true.
20 // This just makes error return conditions a little bit simpler...
22 static inline bool Error(std::string *E, const std::string &Message) {
27 // LinkTypes - Go through the symbol table of the Src module and see if any
28 // types are named in the src module that are not named in the Dst module.
29 // Make sure there are no type name conflicts.
31 static bool LinkTypes(Module *Dest, const Module *Src, std::string *Err) {
32 SymbolTable *DestST = &Dest->getSymbolTable();
33 const SymbolTable *SrcST = &Src->getSymbolTable();
35 // Look for a type plane for Type's...
36 SymbolTable::const_iterator PI = SrcST->find(Type::TypeTy);
37 if (PI == SrcST->end()) return false; // No named types, do nothing.
39 const SymbolTable::VarMap &VM = PI->second;
40 for (SymbolTable::type_const_iterator I = VM.begin(), E = VM.end();
42 const std::string &Name = I->first;
43 const Type *RHS = cast<Type>(I->second);
45 // Check to see if this type name is already in the dest module...
46 const Type *Entry = cast_or_null<Type>(DestST->lookup(Type::TypeTy, Name));
47 if (Entry && !isa<OpaqueType>(Entry)) { // Yup, the value already exists...
49 if (OpaqueType *OT = dyn_cast<OpaqueType>(const_cast<Type*>(RHS))) {
50 OT->refineAbstractTypeTo(Entry);
52 // If it's the same, noop. Otherwise, error.
53 return Error(Err, "Type named '" + Name +
54 "' of different shape in modules.\n Src='" +
55 Entry->getDescription() + "'.\n Dst='" +
56 RHS->getDescription() + "'");
59 } else { // Type not in dest module. Add it now.
61 OpaqueType *OT = cast<OpaqueType>(const_cast<Type*>(Entry));
62 OT->refineAbstractTypeTo(RHS);
65 // TODO: FIXME WHEN TYPES AREN'T CONST
66 DestST->insert(Name, const_cast<Type*>(RHS));
72 static void PrintMap(const std::map<const Value*, Value*> &M) {
73 for (std::map<const Value*, Value*>::const_iterator I = M.begin(), E =M.end();
75 std::cerr << " Fr: " << (void*)I->first << " ";
77 std::cerr << " To: " << (void*)I->second << " ";
84 // RemapOperand - Use LocalMap and GlobalMap to convert references from one
85 // module to another. This is somewhat sophisticated in that it can
86 // automatically handle constant references correctly as well...
88 static Value *RemapOperand(const Value *In,
89 std::map<const Value*, Value*> &LocalMap,
90 std::map<const Value*, Value*> *GlobalMap) {
91 std::map<const Value*,Value*>::const_iterator I = LocalMap.find(In);
92 if (I != LocalMap.end()) return I->second;
95 I = GlobalMap->find(In);
96 if (I != GlobalMap->end()) return I->second;
99 // Check to see if it's a constant that we are interesting in transforming...
100 if (const Constant *CPV = dyn_cast<Constant>(In)) {
101 if (!isa<DerivedType>(CPV->getType()) && !isa<ConstantExpr>(CPV))
102 return const_cast<Constant*>(CPV); // Simple constants stay identical...
104 Constant *Result = 0;
106 if (const ConstantArray *CPA = dyn_cast<ConstantArray>(CPV)) {
107 const std::vector<Use> &Ops = CPA->getValues();
108 std::vector<Constant*> Operands(Ops.size());
109 for (unsigned i = 0, e = Ops.size(); i != e; ++i)
111 cast<Constant>(RemapOperand(Ops[i], LocalMap, GlobalMap));
112 Result = ConstantArray::get(cast<ArrayType>(CPA->getType()), Operands);
113 } else if (const ConstantStruct *CPS = dyn_cast<ConstantStruct>(CPV)) {
114 const std::vector<Use> &Ops = CPS->getValues();
115 std::vector<Constant*> Operands(Ops.size());
116 for (unsigned i = 0; i < Ops.size(); ++i)
118 cast<Constant>(RemapOperand(Ops[i], LocalMap, GlobalMap));
119 Result = ConstantStruct::get(cast<StructType>(CPS->getType()), Operands);
120 } else if (isa<ConstantPointerNull>(CPV)) {
121 Result = const_cast<Constant*>(CPV);
122 } else if (const ConstantPointerRef *CPR =
123 dyn_cast<ConstantPointerRef>(CPV)) {
124 Value *V = RemapOperand(CPR->getValue(), LocalMap, GlobalMap);
125 Result = ConstantPointerRef::get(cast<GlobalValue>(V));
126 } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CPV)) {
127 if (CE->getOpcode() == Instruction::GetElementPtr) {
128 Value *Ptr = RemapOperand(CE->getOperand(0), LocalMap, GlobalMap);
129 std::vector<Constant*> Indices;
130 Indices.reserve(CE->getNumOperands()-1);
131 for (unsigned i = 1, e = CE->getNumOperands(); i != e; ++i)
132 Indices.push_back(cast<Constant>(RemapOperand(CE->getOperand(i),
133 LocalMap, GlobalMap)));
135 Result = ConstantExpr::getGetElementPtr(cast<Constant>(Ptr), Indices);
136 } else if (CE->getNumOperands() == 1) {
138 assert(CE->getOpcode() == Instruction::Cast);
139 Value *V = RemapOperand(CE->getOperand(0), LocalMap, GlobalMap);
140 Result = ConstantExpr::getCast(cast<Constant>(V), CE->getType());
141 } else if (CE->getNumOperands() == 2) {
142 // Binary operator...
143 Value *V1 = RemapOperand(CE->getOperand(0), LocalMap, GlobalMap);
144 Value *V2 = RemapOperand(CE->getOperand(1), LocalMap, GlobalMap);
146 Result = ConstantExpr::get(CE->getOpcode(), cast<Constant>(V1),
149 assert(0 && "Unknown constant expr type!");
153 assert(0 && "Unknown type of derived type constant value!");
156 // Cache the mapping in our local map structure...
158 GlobalMap->insert(std::make_pair(In, Result));
160 LocalMap.insert(std::make_pair(In, Result));
164 std::cerr << "XXX LocalMap: \n";
168 std::cerr << "XXX GlobalMap: \n";
169 PrintMap(*GlobalMap);
172 std::cerr << "Couldn't remap value: " << (void*)In << " " << *In << "\n";
173 assert(0 && "Couldn't remap value!");
178 // LinkGlobals - Loop through the global variables in the src module and merge
179 // them into the dest module.
181 static bool LinkGlobals(Module *Dest, const Module *Src,
182 std::map<const Value*, Value*> &ValueMap,
183 std::multimap<std::string, GlobalVariable *> &AppendingVars,
185 // We will need a module level symbol table if the src module has a module
186 // level symbol table...
187 SymbolTable *ST = (SymbolTable*)&Dest->getSymbolTable();
189 // Loop over all of the globals in the src module, mapping them over as we go
191 for (Module::const_giterator I = Src->gbegin(), E = Src->gend(); I != E; ++I){
192 const GlobalVariable *SGV = I;
193 GlobalVariable *DGV = 0;
194 if (SGV->hasName()) {
195 // A same named thing is a global variable, because the only two things
196 // that may be in a module level symbol table are Global Vars and
197 // Functions, and they both have distinct, nonoverlapping, possible types.
199 DGV = cast_or_null<GlobalVariable>(ST->lookup(SGV->getType(),
203 assert(SGV->hasInitializer() || SGV->hasExternalLinkage() &&
204 "Global must either be external or have an initializer!");
206 bool SGExtern = SGV->isExternal();
207 bool DGExtern = DGV ? DGV->isExternal() : false;
209 if (!DGV || DGV->hasInternalLinkage() || SGV->hasInternalLinkage()) {
210 // No linking to be performed, simply create an identical version of the
211 // symbol over in the dest module... the initializer will be filled in
212 // later by LinkGlobalInits...
214 GlobalVariable *NewDGV =
215 new GlobalVariable(SGV->getType()->getElementType(),
216 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
217 SGV->getName(), Dest);
219 // If the LLVM runtime renamed the global, but it is an externally visible
220 // symbol, DGV must be an existing global with internal linkage. Rename
222 if (NewDGV->getName() != SGV->getName() && !NewDGV->hasInternalLinkage()){
223 assert(DGV && DGV->getName() == SGV->getName() &&
224 DGV->hasInternalLinkage());
226 NewDGV->setName(SGV->getName()); // Force the name back
227 DGV->setName(SGV->getName()); // This will cause a renaming
228 assert(NewDGV->getName() == SGV->getName() &&
229 DGV->getName() != SGV->getName());
232 // Make sure to remember this mapping...
233 ValueMap.insert(std::make_pair(SGV, NewDGV));
234 if (SGV->hasAppendingLinkage())
235 // Keep track that this is an appending variable...
236 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV));
238 } else if (SGV->isExternal()) {
239 // If SGV is external or if both SGV & DGV are external.. Just link the
240 // external globals, we aren't adding anything.
241 ValueMap.insert(std::make_pair(SGV, DGV));
243 } else if (DGV->isExternal()) { // If DGV is external but SGV is not...
244 ValueMap.insert(std::make_pair(SGV, DGV));
245 DGV->setLinkage(SGV->getLinkage()); // Inherit linkage!
246 } else if (SGV->getLinkage() != DGV->getLinkage()) {
247 return Error(Err, "Global variables named '" + SGV->getName() +
248 "' have different linkage specifiers!");
249 } else if (SGV->hasExternalLinkage()) {
250 // Allow linking two exactly identical external global variables...
251 if (SGV->isConstant() != DGV->isConstant() ||
252 SGV->getInitializer() != DGV->getInitializer())
253 return Error(Err, "Global Variable Collision on '" +
254 SGV->getType()->getDescription() + " %" + SGV->getName() +
255 "' - Global variables differ in const'ness");
256 ValueMap.insert(std::make_pair(SGV, DGV));
257 } else if (SGV->hasLinkOnceLinkage()) {
258 // If the global variable has a name, and that name is already in use in
259 // the Dest module, make sure that the name is a compatible global
262 // Check to see if the two GV's have the same Const'ness...
263 if (SGV->isConstant() != DGV->isConstant())
264 return Error(Err, "Global Variable Collision on '" +
265 SGV->getType()->getDescription() + " %" + SGV->getName() +
266 "' - Global variables differ in const'ness");
268 // Okay, everything is cool, remember the mapping...
269 ValueMap.insert(std::make_pair(SGV, DGV));
270 } else if (SGV->hasAppendingLinkage()) {
271 // No linking is performed yet. Just insert a new copy of the global, and
272 // keep track of the fact that it is an appending variable in the
273 // AppendingVars map. The name is cleared out so that no linkage is
275 GlobalVariable *NewDGV =
276 new GlobalVariable(SGV->getType()->getElementType(),
277 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
280 // Make sure to remember this mapping...
281 ValueMap.insert(std::make_pair(SGV, NewDGV));
283 // Keep track that this is an appending variable...
284 AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV));
286 assert(0 && "Unknown linkage!");
293 // LinkGlobalInits - Update the initializers in the Dest module now that all
294 // globals that may be referenced are in Dest.
296 static bool LinkGlobalInits(Module *Dest, const Module *Src,
297 std::map<const Value*, Value*> &ValueMap,
300 // Loop over all of the globals in the src module, mapping them over as we go
302 for (Module::const_giterator I = Src->gbegin(), E = Src->gend(); I != E; ++I){
303 const GlobalVariable *SGV = I;
305 if (SGV->hasInitializer()) { // Only process initialized GV's
306 // Figure out what the initializer looks like in the dest module...
308 cast<Constant>(RemapOperand(SGV->getInitializer(), ValueMap, 0));
310 GlobalVariable *DGV = cast<GlobalVariable>(ValueMap[SGV]);
311 if (DGV->hasInitializer()) {
312 assert(SGV->getLinkage() == DGV->getLinkage());
313 if (SGV->hasExternalLinkage()) {
314 if (DGV->getInitializer() != SInit)
315 return Error(Err, "Global Variable Collision on '" +
316 SGV->getType()->getDescription() +"':%"+SGV->getName()+
317 " - Global variables have different initializers");
318 } else if (DGV->hasLinkOnceLinkage()) {
319 // Nothing is required, mapped values will take the new global
321 } else if (DGV->hasAppendingLinkage()) {
322 assert(0 && "Appending linkage unimplemented!");
324 assert(0 && "Unknown linkage!");
327 // Copy the initializer over now...
328 DGV->setInitializer(SInit);
335 // LinkFunctionProtos - Link the functions together between the two modules,
336 // without doing function bodies... this just adds external function prototypes
337 // to the Dest function...
339 static bool LinkFunctionProtos(Module *Dest, const Module *Src,
340 std::map<const Value*, Value*> &ValueMap,
342 SymbolTable *ST = (SymbolTable*)&Dest->getSymbolTable();
344 // Loop over all of the functions in the src module, mapping them over as we
347 for (Module::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) {
348 const Function *SF = I; // SrcFunction
351 // The same named thing is a Function, because the only two things
352 // that may be in a module level symbol table are Global Vars and
353 // Functions, and they both have distinct, nonoverlapping, possible types.
355 DF = cast_or_null<Function>(ST->lookup(SF->getType(), SF->getName()));
357 if (!DF || SF->hasInternalLinkage() || DF->hasInternalLinkage()) {
358 // Function does not already exist, simply insert an function signature
359 // identical to SF into the dest module...
360 Function *NewDF = new Function(SF->getFunctionType(), SF->getLinkage(),
361 SF->getName(), Dest);
363 // If the LLVM runtime renamed the function, but it is an externally
364 // visible symbol, DF must be an existing function with internal linkage.
366 if (NewDF->getName() != SF->getName() && !NewDF->hasInternalLinkage()) {
367 assert(DF && DF->getName() == SF->getName() &&DF->hasInternalLinkage());
369 NewDF->setName(SF->getName()); // Force the name back
370 DF->setName(SF->getName()); // This will cause a renaming
371 assert(NewDF->getName() == SF->getName() &&
372 DF->getName() != SF->getName());
375 // ... and remember this mapping...
376 ValueMap.insert(std::make_pair(SF, NewDF));
377 } else if (SF->isExternal()) {
378 // If SF is external or if both SF & DF are external.. Just link the
379 // external functions, we aren't adding anything.
380 ValueMap.insert(std::make_pair(SF, DF));
381 } else if (DF->isExternal()) { // If DF is external but SF is not...
382 // Link the external functions, update linkage qualifiers
383 ValueMap.insert(std::make_pair(SF, DF));
384 DF->setLinkage(SF->getLinkage());
386 } else if (SF->getLinkage() != DF->getLinkage()) {
387 return Error(Err, "Functions named '" + SF->getName() +
388 "' have different linkage specifiers!");
389 } else if (SF->hasExternalLinkage()) {
390 // The function is defined in both modules!!
391 return Error(Err, "Function '" +
392 SF->getFunctionType()->getDescription() + "':\"" +
393 SF->getName() + "\" - Function is already defined!");
394 } else if (SF->hasLinkOnceLinkage()) {
395 // Completely ignore the source function.
396 ValueMap.insert(std::make_pair(SF, DF));
398 assert(0 && "Unknown linkage configuration found!");
404 // LinkFunctionBody - Copy the source function over into the dest function and
405 // fix up references to values. At this point we know that Dest is an external
406 // function, and that Src is not.
408 static bool LinkFunctionBody(Function *Dest, const Function *Src,
409 std::map<const Value*, Value*> &GlobalMap,
411 assert(Src && Dest && Dest->isExternal() && !Src->isExternal());
412 std::map<const Value*, Value*> LocalMap; // Map for function local values
414 // Go through and convert function arguments over...
415 Function::aiterator DI = Dest->abegin();
416 for (Function::const_aiterator I = Src->abegin(), E = Src->aend();
418 DI->setName(I->getName()); // Copy the name information over...
420 // Add a mapping to our local map
421 LocalMap.insert(std::make_pair(I, DI));
424 // Loop over all of the basic blocks, copying the instructions over...
426 for (Function::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) {
427 // Create new basic block and add to mapping and the Dest function...
428 BasicBlock *DBB = new BasicBlock(I->getName(), Dest);
429 LocalMap.insert(std::make_pair(I, DBB));
431 // Loop over all of the instructions in the src basic block, copying them
432 // over. Note that this is broken in a strict sense because the cloned
433 // instructions will still be referencing values in the Src module, not
434 // the remapped values. In our case, however, we will not get caught and
435 // so we can delay patching the values up until later...
437 for (BasicBlock::const_iterator II = I->begin(), IE = I->end();
439 Instruction *DI = II->clone();
440 DI->setName(II->getName());
441 DBB->getInstList().push_back(DI);
442 LocalMap.insert(std::make_pair(II, DI));
446 // At this point, all of the instructions and values of the function are now
447 // copied over. The only problem is that they are still referencing values in
448 // the Source function as operands. Loop through all of the operands of the
449 // functions and patch them up to point to the local versions...
451 for (Function::iterator BB = Dest->begin(), BE = Dest->end(); BB != BE; ++BB)
452 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
453 for (Instruction::op_iterator OI = I->op_begin(), OE = I->op_end();
455 *OI = RemapOperand(*OI, LocalMap, &GlobalMap);
461 // LinkFunctionBodies - Link in the function bodies that are defined in the
462 // source module into the DestModule. This consists basically of copying the
463 // function over and fixing up references to values.
465 static bool LinkFunctionBodies(Module *Dest, const Module *Src,
466 std::map<const Value*, Value*> &ValueMap,
469 // Loop over all of the functions in the src module, mapping them over as we
472 for (Module::const_iterator SF = Src->begin(), E = Src->end(); SF != E; ++SF){
473 if (!SF->isExternal()) { // No body if function is external
474 Function *DF = cast<Function>(ValueMap[SF]); // Destination function
476 // DF not external SF external?
477 if (!DF->isExternal()) {
478 if (DF->hasLinkOnceLinkage()) continue; // No relinkage for link-once!
480 *Err = "Function '" + (SF->hasName() ? SF->getName() :std::string(""))
481 + "' body multiply defined!";
485 if (LinkFunctionBody(DF, SF, ValueMap, Err)) return true;
491 // LinkAppendingVars - If there were any appending global variables, link them
492 // together now. Return true on error.
494 static bool LinkAppendingVars(Module *M,
495 std::multimap<std::string, GlobalVariable *> &AppendingVars,
496 std::string *ErrorMsg) {
497 if (AppendingVars.empty()) return false; // Nothing to do.
499 // Loop over the multimap of appending vars, processing any variables with the
500 // same name, forming a new appending global variable with both of the
501 // initializers merged together, then rewrite references to the old variables
504 std::vector<Constant*> Inits;
505 while (AppendingVars.size() > 1) {
506 // Get the first two elements in the map...
507 std::multimap<std::string,
508 GlobalVariable*>::iterator Second = AppendingVars.begin(), First=Second++;
510 // If the first two elements are for different names, there is no pair...
511 // Otherwise there is a pair, so link them together...
512 if (First->first == Second->first) {
513 GlobalVariable *G1 = First->second, *G2 = Second->second;
514 const ArrayType *T1 = cast<ArrayType>(G1->getType()->getElementType());
515 const ArrayType *T2 = cast<ArrayType>(G2->getType()->getElementType());
517 // Check to see that they two arrays agree on type...
518 if (T1->getElementType() != T2->getElementType())
519 return Error(ErrorMsg,
520 "Appending variables with different element types need to be linked!");
521 if (G1->isConstant() != G2->isConstant())
522 return Error(ErrorMsg,
523 "Appending variables linked with different const'ness!");
525 unsigned NewSize = T1->getNumElements() + T2->getNumElements();
526 ArrayType *NewType = ArrayType::get(T1->getElementType(), NewSize);
528 // Create the new global variable...
530 new GlobalVariable(NewType, G1->isConstant(), G1->getLinkage(),
531 /*init*/0, First->first, M);
533 // Merge the initializer...
534 Inits.reserve(NewSize);
535 ConstantArray *I = cast<ConstantArray>(G1->getInitializer());
536 for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i)
537 Inits.push_back(cast<Constant>(I->getValues()[i]));
538 I = cast<ConstantArray>(G2->getInitializer());
539 for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i)
540 Inits.push_back(cast<Constant>(I->getValues()[i]));
541 NG->setInitializer(ConstantArray::get(NewType, Inits));
544 // Replace any uses of the two global variables with uses of the new
547 // FIXME: This should rewrite simple/straight-forward uses such as
548 // getelementptr instructions to not use the Cast!
549 ConstantPointerRef *NGCP = ConstantPointerRef::get(NG);
550 G1->replaceAllUsesWith(ConstantExpr::getCast(NGCP, G1->getType()));
551 G2->replaceAllUsesWith(ConstantExpr::getCast(NGCP, G2->getType()));
553 // Remove the two globals from the module now...
554 M->getGlobalList().erase(G1);
555 M->getGlobalList().erase(G2);
557 // Put the new global into the AppendingVars map so that we can handle
558 // linking of more than two vars...
561 AppendingVars.erase(First);
568 // LinkModules - This function links two modules together, with the resulting
569 // left module modified to be the composite of the two input modules. If an
570 // error occurs, true is returned and ErrorMsg (if not null) is set to indicate
571 // the problem. Upon failure, the Dest module could be in a modified state, and
572 // shouldn't be relied on to be consistent.
574 bool LinkModules(Module *Dest, const Module *Src, std::string *ErrorMsg) {
575 if (Dest->getEndianness() != Src->getEndianness())
576 std::cerr << "WARNING: Linking two modules of different endianness!\n";
577 if (Dest->getPointerSize() != Src->getPointerSize())
578 std::cerr << "WARNING: Linking two modules of different pointer size!\n";
580 // LinkTypes - Go through the symbol table of the Src module and see if any
581 // types are named in the src module that are not named in the Dst module.
582 // Make sure there are no type name conflicts.
584 if (LinkTypes(Dest, Src, ErrorMsg)) return true;
586 // ValueMap - Mapping of values from what they used to be in Src, to what they
589 std::map<const Value*, Value*> ValueMap;
591 // AppendingVars - Keep track of global variables in the destination module
592 // with appending linkage. After the module is linked together, they are
593 // appended and the module is rewritten.
595 std::multimap<std::string, GlobalVariable *> AppendingVars;
597 // Add all of the appending globals already in the Dest module to
599 for (Module::giterator I = Dest->gbegin(), E = Dest->gend(); I != E; ++I)
600 if (I->hasAppendingLinkage())
601 AppendingVars.insert(std::make_pair(I->getName(), I));
603 // Insert all of the globals in src into the Dest module... without linking
604 // initializers (which could refer to functions not yet mapped over).
606 if (LinkGlobals(Dest, Src, ValueMap, AppendingVars, ErrorMsg)) return true;
608 // Link the functions together between the two modules, without doing function
609 // bodies... this just adds external function prototypes to the Dest
610 // function... We do this so that when we begin processing function bodies,
611 // all of the global values that may be referenced are available in our
614 if (LinkFunctionProtos(Dest, Src, ValueMap, ErrorMsg)) return true;
616 // Update the initializers in the Dest module now that all globals that may
617 // be referenced are in Dest.
619 if (LinkGlobalInits(Dest, Src, ValueMap, ErrorMsg)) return true;
621 // Link in the function bodies that are defined in the source module into the
622 // DestModule. This consists basically of copying the function over and
623 // fixing up references to values.
625 if (LinkFunctionBodies(Dest, Src, ValueMap, ErrorMsg)) return true;
627 // If there were any appending global variables, link them together now.
629 if (LinkAppendingVars(Dest, AppendingVars, ErrorMsg)) return true;