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 methods between two modules
10 //===----------------------------------------------------------------------===//
12 #include "llvm/Transforms/Linker.h"
13 #include "llvm/Module.h"
14 #include "llvm/Method.h"
15 #include "llvm/GlobalVariable.h"
16 #include "llvm/SymbolTable.h"
17 #include "llvm/DerivedTypes.h"
18 #include "llvm/iOther.h"
19 #include "llvm/ConstPoolVals.h"
21 // Error - Simple wrapper function to conditionally assign to E and return true.
22 // This just makes error return conditions a little bit simpler...
24 static inline bool Error(string *E, string Message) {
29 #include "llvm/Assembly/Writer.h" // TODO: REMOVE
32 // LinkTypes - Go through the symbol table of the Src module and see if any
33 // types are named in the src module that are not named in the Dst module.
34 // Make sure there are no type name conflicts.
36 static bool LinkTypes(Module *Dest, const Module *Src, string *Err = 0) {
37 // No symbol table? Can't have named types.
38 if (!Src->hasSymbolTable()) return false;
40 SymbolTable *DestST = Dest->getSymbolTableSure();
41 const SymbolTable *SrcST = Src->getSymbolTable();
43 // Look for a type plane for Type's...
44 SymbolTable::const_iterator PI = SrcST->find(Type::TypeTy);
45 if (PI == SrcST->end()) return false; // No named types, do nothing.
47 const SymbolTable::VarMap &VM = PI->second;
48 for (SymbolTable::type_const_iterator I = VM.begin(), E = VM.end();
50 const string &Name = I->first;
51 const Type *RHS = cast<Type>(I->second);
53 // Check to see if this type name is already in the dest module...
54 const Type *Entry = cast_or_null<Type>(DestST->lookup(Type::TypeTy, Name));
55 if (Entry) { // Yup, the value already exists...
56 if (Entry != RHS) // If it's the same, noop. Otherwise, error.
57 return Error(Err, "Type named '" + Name +
58 "' of different shape in modules.\n Src='" +
59 Entry->getDescription() + "'. Dest='" +
60 RHS->getDescription() + "'");
61 } else { // Type not in dest module. Add it now.
62 // TODO: FIXME WHEN TYPES AREN'T CONST
63 DestST->insert(Name, const_cast<Type*>(RHS));
69 static void PrintMap(const map<const Value*, Value*> &M) {
70 for (map<const Value*, Value*>::const_iterator I = M.begin(), E = M.end();
72 cerr << " Fr: " << (void*)I->first << " " << I->first
73 << " To: " << (void*)I->second << " " << I->second << endl;
78 // RemapOperand - Use LocalMap and GlobalMap to convert references from one
79 // module to another. This is somewhat sophisticated in that it can
80 // automatically handle constant references correctly as well...
82 static Value *RemapOperand(const Value *In, map<const Value*, Value*> &LocalMap,
83 const map<const Value*, Value*> *GlobalMap = 0) {
84 map<const Value*,Value*>::const_iterator I = LocalMap.find(In);
85 if (I != LocalMap.end()) return I->second;
88 I = GlobalMap->find(In);
89 if (I != GlobalMap->end()) return I->second;
92 // Check to see if it's a constant that we are interesting in transforming...
93 if (ConstPoolVal *CPV = dyn_cast<ConstPoolVal>(In)) {
94 if (!isa<DerivedType>(CPV->getType()))
95 return CPV; // Simple constants stay identical...
97 ConstPoolVal *Result = 0;
99 if (ConstPoolArray *CPA = dyn_cast<ConstPoolArray>(CPV)) {
100 const vector<Use> &Ops = CPA->getValues();
101 vector<ConstPoolVal*> Operands(Ops.size());
102 for (unsigned i = 0; i < Ops.size(); ++i)
104 cast<ConstPoolVal>(RemapOperand(Ops[i], LocalMap, GlobalMap));
105 Result = ConstPoolArray::get(cast<ArrayType>(CPA->getType()), Operands);
106 } else if (ConstPoolStruct *CPS = dyn_cast<ConstPoolStruct>(CPV)) {
107 const vector<Use> &Ops = CPS->getValues();
108 vector<ConstPoolVal*> Operands(Ops.size());
109 for (unsigned i = 0; i < Ops.size(); ++i)
111 cast<ConstPoolVal>(RemapOperand(Ops[i], LocalMap, GlobalMap));
112 Result = ConstPoolStruct::get(cast<StructType>(CPS->getType()), Operands);
113 } else if (isa<ConstPoolPointerNull>(CPV)) {
115 } else if (ConstPoolPointerRef *CPR = dyn_cast<ConstPoolPointerRef>(CPV)) {
116 Value *V = RemapOperand(CPR->getValue(), LocalMap, GlobalMap);
117 Result = ConstPoolPointerRef::get(cast<GlobalValue>(V));
119 assert(0 && "Unknown type of derived type constant value!");
122 // Cache the mapping in our local map structure...
123 LocalMap.insert(make_pair(In, CPV));
127 cerr << "XXX LocalMap: \n";
131 cerr << "XXX GlobalMap: \n";
132 PrintMap(*GlobalMap);
135 cerr << "Couldn't remap value: " << (void*)In << " " << In << endl;
136 assert(0 && "Couldn't remap value!");
141 // LinkGlobals - Loop through the global variables in the src module and merge
142 // them into the dest module...
144 static bool LinkGlobals(Module *Dest, const Module *Src,
145 map<const Value*, Value*> &ValueMap, string *Err = 0) {
146 // We will need a module level symbol table if the src module has a module
147 // level symbol table...
148 SymbolTable *ST = Src->getSymbolTable() ? Dest->getSymbolTableSure() : 0;
150 // Loop over all of the globals in the src module, mapping them over as we go
152 for (Module::const_giterator I = Src->gbegin(), E = Src->gend(); I != E; ++I){
153 const GlobalVariable *SGV = *I;
156 // If the global variable has a name, and that name is already in use in the
157 // Dest module, make sure that the name is a compatible global variable...
159 if (SGV->hasName() && (V = ST->lookup(SGV->getType(), SGV->getName()))) {
160 // The same named thing is a global variable, because the only two things
161 // that may be in a module level symbol table are Global Vars and Methods,
162 // and they both have distinct, nonoverlapping, possible types.
164 GlobalVariable *DGV = cast<GlobalVariable>(V);
166 // Check to see if the two GV's have the same Const'ness...
167 if (SGV->isConstant() != DGV->isConstant())
168 return Error(Err, "Global Variable Collision on '" +
169 SGV->getType()->getDescription() + "':%" + SGV->getName() +
170 " - Global variables differ in const'ness");
172 // Okay, everything is cool, remember the mapping...
173 ValueMap.insert(make_pair(SGV, DGV));
175 // No linking to be performed, simply create an identical version of the
176 // symbol over in the dest module... the initializer will be filled in
177 // later by LinkGlobalInits...
179 GlobalVariable *DGV =
180 new GlobalVariable(SGV->getType()->getValueType(), SGV->isConstant(),
183 // Add the new global to the dest module
184 Dest->getGlobalList().push_back(DGV);
186 // Make sure to remember this mapping...
187 ValueMap.insert(make_pair(SGV, DGV));
194 // LinkGlobalInits - Update the initializers in the Dest module now that all
195 // globals that may be referenced are in Dest.
197 static bool LinkGlobalInits(Module *Dest, const Module *Src,
198 map<const Value*, Value*> &ValueMap,
201 // Loop over all of the globals in the src module, mapping them over as we go
203 for (Module::const_giterator I = Src->gbegin(), E = Src->gend(); I != E; ++I){
204 const GlobalVariable *SGV = *I;
206 if (SGV->hasInitializer()) { // Only process initialized GV's
207 // Figure out what the initializer looks like in the dest module...
208 ConstPoolVal *DInit =
209 cast<ConstPoolVal>(RemapOperand(SGV->getInitializer(), ValueMap));
211 GlobalVariable *DGV = cast<GlobalVariable>(ValueMap[SGV]);
212 if (DGV->hasInitializer()) {
213 if (DGV->getInitializer() != DInit)
214 return Error(Err, "Global Variable Collision on '" +
215 SGV->getType()->getDescription() + "':%" +SGV->getName()+
216 " - Global variables have different initializers");
218 // Copy the initializer over now...
219 DGV->setInitializer(DInit);
226 // LinkMethodProtos - Link the methods together between the two modules, without
227 // doing method bodies... this just adds external method prototypes to the Dest
230 static bool LinkMethodProtos(Module *Dest, const Module *Src,
231 map<const Value*, Value*> &ValueMap,
233 // We will need a module level symbol table if the src module has a module
234 // level symbol table...
235 SymbolTable *ST = Src->getSymbolTable() ? Dest->getSymbolTableSure() : 0;
237 // Loop over all of the methods in the src module, mapping them over as we go
239 for (Module::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) {
240 const Method *SM = *I; // SrcMethod
243 // If the method has a name, and that name is already in use in the
244 // Dest module, make sure that the name is a compatible method...
246 if (SM->hasName() && (V = ST->lookup(SM->getType(), SM->getName()))) {
247 // The same named thing is a Method, because the only two things
248 // that may be in a module level symbol table are Global Vars and Methods,
249 // and they both have distinct, nonoverlapping, possible types.
251 Method *DM = cast<Method>(V); // DestMethod
253 // Check to make sure the method is not defined in both modules...
254 if (!SM->isExternal() && !DM->isExternal())
255 return Error(Err, "Method '" +
256 SM->getMethodType()->getDescription() + "':\"" +
257 SM->getName() + "\" - Method is already defined!");
259 // Otherwise, just remember this mapping...
260 ValueMap.insert(make_pair(SM, DM));
262 // Method does not already exist, simply insert an external method
263 // signature identical to SM into the dest module...
264 Method *DM = new Method(SM->getMethodType(), SM->getName());
266 // Add the method signature to the dest module...
267 Dest->getMethodList().push_back(DM);
269 // ... and remember this mapping...
270 ValueMap.insert(make_pair(SM, DM));
276 // LinkMethodBody - Copy the source method over into the dest method and fix up
277 // references to values. At this point we know that Dest is an external method,
278 // and that Src is not.
280 static bool LinkMethodBody(Method *Dest, const Method *Src,
281 const map<const Value*, Value*> &GlobalMap,
283 assert(Src && Dest && Dest->isExternal() && !Src->isExternal());
284 map<const Value*, Value*> LocalMap; // Map for method local values
286 // Go through and convert method arguments over...
287 for (Method::ArgumentListType::const_iterator
288 I = Src->getArgumentList().begin(),
289 E = Src->getArgumentList().end(); I != E; ++I) {
290 const MethodArgument *SMA = *I;
292 // Create the new method argument and add to the dest method...
293 MethodArgument *DMA = new MethodArgument(SMA->getType(), SMA->getName());
294 Dest->getArgumentList().push_back(DMA);
296 // Add a mapping to our local map
297 LocalMap.insert(make_pair(SMA, DMA));
300 // Loop over all of the basic blocks, copying the instructions over...
302 for (Method::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) {
303 const BasicBlock *SBB = *I;
305 // Create new basic block and add to mapping and the Dest method...
306 BasicBlock *DBB = new BasicBlock(SBB->getName(), Dest);
307 LocalMap.insert(make_pair(SBB, DBB));
309 // Loop over all of the instructions in the src basic block, copying them
310 // over. Note that this is broken in a strict sense because the cloned
311 // instructions will still be referencing values in the Src module, not
312 // the remapped values. In our case, however, we will not get caught and
313 // so we can delay patching the values up until later...
315 for (BasicBlock::const_iterator II = SBB->begin(), IE = SBB->end();
317 const Instruction *SI = *II;
318 Instruction *DI = SI->clone();
319 DI->setName(SI->getName());
320 DBB->getInstList().push_back(DI);
321 LocalMap.insert(make_pair(SI, DI));
325 // At this point, all of the instructions and values of the method are now
326 // copied over. The only problem is that they are still referencing values
327 // in the Source method as operands. Loop through all of the operands of the
328 // methods and patch them up to point to the local versions...
330 for (Method::inst_iterator I = Dest->inst_begin(), E = Dest->inst_end();
332 Instruction *Inst = *I;
334 for (Instruction::op_iterator OI = Inst->op_begin(), OE = Inst->op_end();
336 *OI = RemapOperand(*OI, LocalMap, &GlobalMap);
343 // LinkMethodBodies - Link in the method bodies that are defined in the source
344 // module into the DestModule. This consists basically of copying the method
345 // over and fixing up references to values.
347 static bool LinkMethodBodies(Module *Dest, const Module *Src,
348 map<const Value*, Value*> &ValueMap,
351 // Loop over all of the methods in the src module, mapping them over as we go
353 for (Module::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) {
354 const Method *SM = *I; // Source Method
355 if (!SM->isExternal()) { // No body if method is external
356 Method *DM = cast<Method>(ValueMap[SM]); // Destination method
358 // DM not external SM external?
359 if (!DM->isExternal()) {
361 *Err = "Method '" + (SM->hasName() ? SM->getName() : string("")) +
362 "' body multiply defined!";
366 if (LinkMethodBody(DM, SM, ValueMap, Err)) return true;
374 // LinkModules - This function links two modules together, with the resulting
375 // left module modified to be the composite of the two input modules. If an
376 // error occurs, true is returned and ErrorMsg (if not null) is set to indicate
377 // the problem. Upon failure, the Dest module could be in a modified state, and
378 // shouldn't be relied on to be consistent.
380 bool LinkModules(Module *Dest, const Module *Src, string *ErrorMsg = 0) {
382 // LinkTypes - Go through the symbol table of the Src module and see if any
383 // types are named in the src module that are not named in the Dst module.
384 // Make sure there are no type name conflicts.
386 if (LinkTypes(Dest, Src, ErrorMsg)) return true;
388 // ValueMap - Mapping of values from what they used to be in Src, to what they
391 map<const Value*, Value*> ValueMap;
393 // Insert all of the globals in src into the Dest module... without
395 if (LinkGlobals(Dest, Src, ValueMap, ErrorMsg)) return true;
397 // Update the initializers in the Dest module now that all globals that may
398 // be referenced are in Dest.
400 if (LinkGlobalInits(Dest, Src, ValueMap, ErrorMsg)) return true;
402 // Link the methods together between the two modules, without doing method
403 // bodies... this just adds external method prototypes to the Dest method...
404 // We do this so that when we begin processing method bodies, all of the
405 // global values that may be referenced are available in our ValueMap.
407 if (LinkMethodProtos(Dest, Src, ValueMap, ErrorMsg)) return true;
409 // Link in the method bodies that are defined in the source module into the
410 // DestModule. This consists basically of copying the method over and fixing
411 // up references to values.
413 if (LinkMethodBodies(Dest, Src, ValueMap, ErrorMsg)) return true;