1 //===-- SlotCalculator.cpp - Calculate what slots values land in ----------===//
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 a useful analysis step to figure out what numbered
11 // slots values in a program will land in (keeping track of per plane
12 // information as required.
14 // This is used primarily for when writing a file to disk, either in bytecode
17 //===----------------------------------------------------------------------===//
19 #include "llvm/SlotCalculator.h"
20 #include "llvm/Analysis/ConstantsScanner.h"
21 #include "llvm/Module.h"
22 #include "llvm/iOther.h"
23 #include "llvm/Constant.h"
24 #include "llvm/DerivedTypes.h"
25 #include "llvm/SymbolTable.h"
26 #include "Support/PostOrderIterator.h"
27 #include "Support/STLExtras.h"
32 #define SC_DEBUG(X) std::cerr << X
37 SlotCalculator::SlotCalculator(const Module *M, bool IgnoreNamed) {
38 IgnoreNamedNodes = IgnoreNamed;
41 // Preload table... Make sure that all of the primitive types are in the table
42 // and that their Primitive ID is equal to their slot #
44 SC_DEBUG("Inserting primitive types:\n");
45 for (unsigned i = 0; i < Type::FirstDerivedTyID; ++i) {
46 assert(Type::getPrimitiveType((Type::PrimitiveID)i));
47 insertValue(Type::getPrimitiveType((Type::PrimitiveID)i), true);
50 if (M == 0) return; // Empty table...
54 SlotCalculator::SlotCalculator(const Function *M, bool IgnoreNamed) {
55 IgnoreNamedNodes = IgnoreNamed;
56 TheModule = M ? M->getParent() : 0;
58 // Preload table... Make sure that all of the primitive types are in the table
59 // and that their Primitive ID is equal to their slot #
61 SC_DEBUG("Inserting primitive types:\n");
62 for (unsigned i = 0; i < Type::FirstDerivedTyID; ++i) {
63 assert(Type::getPrimitiveType((Type::PrimitiveID)i));
64 insertValue(Type::getPrimitiveType((Type::PrimitiveID)i), true);
67 if (TheModule == 0) return; // Empty table...
69 processModule(); // Process module level stuff
70 incorporateFunction(M); // Start out in incorporated state
74 // processModule - Process all of the module level function declarations and
75 // types that are available.
77 void SlotCalculator::processModule() {
78 SC_DEBUG("begin processModule!\n");
80 // Add all of the global variables to the value table...
82 for (Module::const_giterator I = TheModule->gbegin(), E = TheModule->gend();
86 // Scavenge the types out of the functions, then add the functions themselves
87 // to the value table...
89 for (Module::const_iterator I = TheModule->begin(), E = TheModule->end();
93 // Add all of the module level constants used as initializers
95 for (Module::const_giterator I = TheModule->gbegin(), E = TheModule->gend();
97 if (I->hasInitializer())
98 getOrCreateSlot(I->getInitializer());
101 // FIXME: Empirically, this causes the bytecode files to get BIGGER, because
102 // it explodes the operand size numbers to be bigger than can be handled
103 // compactly, which offsets the ~40% savings in constant sizes. Whoops.
105 // If we are emitting a bytecode file, scan all of the functions for their
106 // constants, which allows us to emit more compact modules. This is optional,
107 // and is just used to compactify the constants used by different functions
109 if (!IgnoreNamedNodes) {
110 SC_DEBUG("Inserting function constants:\n");
111 for (Module::const_iterator F = TheModule->begin(), E = TheModule->end();
113 for_each(constant_begin(F), constant_end(F),
114 bind_obj(this, &SlotCalculator::getOrCreateSlot));
118 // Insert constants that are named at module level into the slot pool so that
119 // the module symbol table can refer to them...
121 if (!IgnoreNamedNodes) {
122 SC_DEBUG("Inserting SymbolTable values:\n");
123 processSymbolTable(&TheModule->getSymbolTable());
126 // Now that we have collected together all of the information relevant to the
127 // module, compactify the type table if it is particularly big and outputting
128 // a bytecode file. The basic problem we run into is that some programs have
129 // a large number of types, which causes the type field to overflow its size,
130 // which causes instructions to explode in size (particularly call
131 // instructions). To avoid this behavior, we "sort" the type table so that
132 // all non-value types are pushed to the end of the type table, giving nice
133 // low numbers to the types that can be used by instructions, thus reducing
134 // the amount of explodage we suffer.
135 if (!IgnoreNamedNodes && Table[Type::TypeTyID].size() >= 64) {
136 // Scan through the type table moving value types to the start of the table.
137 TypePlane *Types = &Table[Type::TypeTyID];
138 unsigned FirstNonValueTypeID = 0;
139 for (unsigned i = 0, e = Types->size(); i != e; ++i)
140 if (cast<Type>((*Types)[i])->isFirstClassType() ||
141 cast<Type>((*Types)[i])->isPrimitiveType()) {
142 // Check to see if we have to shuffle this type around. If not, don't
144 if (i != FirstNonValueTypeID) {
145 assert(i != Type::TypeTyID && FirstNonValueTypeID != Type::TypeTyID &&
146 "Cannot move around the type plane!");
148 // Swap the type ID's.
149 std::swap((*Types)[i], (*Types)[FirstNonValueTypeID]);
151 // Keep the NodeMap up to date.
152 NodeMap[(*Types)[i]] = i;
153 NodeMap[(*Types)[FirstNonValueTypeID]] = FirstNonValueTypeID;
155 // When we move a type, make sure to move its value plane as needed.
156 if (Table.size() > FirstNonValueTypeID) {
157 if (Table.size() <= i) Table.resize(i+1);
158 std::swap(Table[i], Table[FirstNonValueTypeID]);
159 Types = &Table[Type::TypeTyID];
162 ++FirstNonValueTypeID;
166 SC_DEBUG("end processModule!\n");
169 // processSymbolTable - Insert all of the values in the specified symbol table
170 // into the values table...
172 void SlotCalculator::processSymbolTable(const SymbolTable *ST) {
173 for (SymbolTable::const_iterator I = ST->begin(), E = ST->end(); I != E; ++I)
174 for (SymbolTable::type_const_iterator TI = I->second.begin(),
175 TE = I->second.end(); TI != TE; ++TI)
176 getOrCreateSlot(TI->second);
179 void SlotCalculator::processSymbolTableConstants(const SymbolTable *ST) {
180 for (SymbolTable::const_iterator I = ST->begin(), E = ST->end(); I != E; ++I)
181 for (SymbolTable::type_const_iterator TI = I->second.begin(),
182 TE = I->second.end(); TI != TE; ++TI)
183 if (isa<Constant>(TI->second))
184 getOrCreateSlot(TI->second);
188 void SlotCalculator::incorporateFunction(const Function *F) {
189 assert(ModuleLevel.size() == 0 && "Module already incorporated!");
191 SC_DEBUG("begin processFunction!\n");
193 // Save the Table state before we process the function...
194 for (unsigned i = 0; i < Table.size(); ++i)
195 ModuleLevel.push_back(Table[i].size());
197 SC_DEBUG("Inserting function arguments\n");
199 // Iterate over function arguments, adding them to the value table...
200 for(Function::const_aiterator I = F->abegin(), E = F->aend(); I != E; ++I)
203 // Iterate over all of the instructions in the function, looking for constant
204 // values that are referenced. Add these to the value pools before any
205 // nonconstant values. This will be turned into the constant pool for the
208 if (!IgnoreNamedNodes) { // Assembly writer does not need this!
209 SC_DEBUG("Inserting function constants:\n";
210 for (constant_iterator I = constant_begin(F), E = constant_end(F);
212 std::cerr << " " << *I->getType() << " " << *I << "\n";
215 // Emit all of the constants that are being used by the instructions in the
217 for_each(constant_begin(F), constant_end(F),
218 bind_obj(this, &SlotCalculator::getOrCreateSlot));
220 // If there is a symbol table, it is possible that the user has names for
221 // constants that are not being used. In this case, we will have problems
222 // if we don't emit the constants now, because otherwise we will get
223 // symbol table references to constants not in the output. Scan for these
226 processSymbolTableConstants(&F->getSymbolTable());
229 SC_DEBUG("Inserting Labels:\n");
231 // Iterate over basic blocks, adding them to the value table...
232 for (Function::const_iterator I = F->begin(), E = F->end(); I != E; ++I)
235 SC_DEBUG("Inserting Instructions:\n");
237 // Add all of the instructions to the type planes...
238 for (Function::const_iterator BB = F->begin(), E = F->end(); BB != E; ++BB)
239 for (BasicBlock::const_iterator I = BB->begin(), E = BB->end(); I!=E; ++I) {
241 if (const VANextInst *VAN = dyn_cast<VANextInst>(I))
242 getOrCreateSlot(VAN->getArgType());
245 if (!IgnoreNamedNodes) {
246 SC_DEBUG("Inserting SymbolTable values:\n");
247 processSymbolTable(&F->getSymbolTable());
250 SC_DEBUG("end processFunction!\n");
253 void SlotCalculator::purgeFunction() {
254 assert(ModuleLevel.size() != 0 && "Module not incorporated!");
255 unsigned NumModuleTypes = ModuleLevel.size();
257 SC_DEBUG("begin purgeFunction!\n");
259 // First, remove values from existing type planes
260 for (unsigned i = 0; i < NumModuleTypes; ++i) {
261 unsigned ModuleSize = ModuleLevel[i]; // Size of plane before function came
262 TypePlane &CurPlane = Table[i];
263 //SC_DEBUG("Processing Plane " <<i<< " of size " << CurPlane.size() <<"\n");
265 while (CurPlane.size() != ModuleSize) {
266 //SC_DEBUG(" Removing [" << i << "] Value=" << CurPlane.back() << "\n");
267 std::map<const Value *, unsigned>::iterator NI =
268 NodeMap.find(CurPlane.back());
269 assert(NI != NodeMap.end() && "Node not in nodemap?");
270 NodeMap.erase(NI); // Erase from nodemap
271 CurPlane.pop_back(); // Shrink plane
275 // We don't need this state anymore, free it up.
278 // Next, remove any type planes defined by the function...
279 while (NumModuleTypes != Table.size()) {
280 TypePlane &Plane = Table.back();
281 SC_DEBUG("Removing Plane " << (Table.size()-1) << " of size "
282 << Plane.size() << "\n");
283 while (Plane.size()) {
284 NodeMap.erase(NodeMap.find(Plane.back())); // Erase from nodemap
285 Plane.pop_back(); // Shrink plane
288 Table.pop_back(); // Nuke the plane, we don't like it.
291 SC_DEBUG("end purgeFunction!\n");
294 int SlotCalculator::getSlot(const Value *D) const {
295 std::map<const Value*, unsigned>::const_iterator I = NodeMap.find(D);
296 if (I == NodeMap.end()) return -1;
298 return (int)I->second;
302 int SlotCalculator::getOrCreateSlot(const Value *V) {
303 int SlotNo = getSlot(V); // Check to see if it's already in!
304 if (SlotNo != -1) return SlotNo;
306 if (!isa<GlobalValue>(V))
307 if (const Constant *C = dyn_cast<Constant>(V)) {
308 // This makes sure that if a constant has uses (for example an array of
309 // const ints), that they are inserted also.
311 for (User::const_op_iterator I = C->op_begin(), E = C->op_end();
316 return insertValue(V);
320 int SlotCalculator::insertValue(const Value *D, bool dontIgnore) {
321 assert(D && "Can't insert a null value!");
322 assert(getSlot(D) == -1 && "Value is already in the table!");
324 // If this node does not contribute to a plane, or if the node has a
325 // name and we don't want names, then ignore the silly node... Note that types
326 // do need slot numbers so that we can keep track of where other values land.
328 if (!dontIgnore) // Don't ignore nonignorables!
329 if (D->getType() == Type::VoidTy || // Ignore void type nodes
330 (IgnoreNamedNodes && // Ignore named and constants
331 (D->hasName() || isa<Constant>(D)) && !isa<Type>(D))) {
332 SC_DEBUG("ignored value " << *D << "\n");
333 return -1; // We do need types unconditionally though
336 // If it's a type, make sure that all subtypes of the type are included...
337 if (const Type *TheTy = dyn_cast<Type>(D)) {
339 // Insert the current type before any subtypes. This is important because
340 // recursive types elements are inserted in a bottom up order. Changing
341 // this here can break things. For example:
343 // global { \2 * } { { \2 }* null }
345 int ResultSlot = doInsertValue(TheTy);
346 SC_DEBUG(" Inserted type: " << TheTy->getDescription() << " slot=" <<
349 // Loop over any contained types in the definition... in post
352 for (po_iterator<const Type*> I = po_begin(TheTy), E = po_end(TheTy);
355 const Type *SubTy = *I;
356 // If we haven't seen this sub type before, add it to our type table!
357 if (getSlot(SubTy) == -1) {
358 SC_DEBUG(" Inserting subtype: " << SubTy->getDescription() << "\n");
359 int Slot = doInsertValue(SubTy);
360 SC_DEBUG(" Inserted subtype: " << SubTy->getDescription() <<
361 " slot=" << Slot << "\n");
368 // Okay, everything is happy, actually insert the silly value now...
369 return doInsertValue(D);
373 // doInsertValue - This is a small helper function to be called only
376 int SlotCalculator::doInsertValue(const Value *D) {
377 const Type *Typ = D->getType();
380 // Used for debugging DefSlot=-1 assertion...
381 //if (Typ == Type::TypeTy)
382 // cerr << "Inserting type '" << cast<Type>(D)->getDescription() << "'!\n";
384 if (Typ->isDerivedType()) {
385 int ValSlot = getSlot(Typ);
386 if (ValSlot == -1) { // Have we already entered this type?
387 // Nope, this is the first we have seen the type, process it.
388 ValSlot = insertValue(Typ, true);
389 assert(ValSlot != -1 && "ProcessType returned -1 for a type?");
391 Ty = (unsigned)ValSlot;
393 Ty = Typ->getPrimitiveID();
396 if (Table.size() <= Ty) // Make sure we have the type plane allocated...
397 Table.resize(Ty+1, TypePlane());
399 // If this is the first value to get inserted into the type plane, make sure
400 // to insert the implicit null value...
401 if (Table[Ty].empty() && Ty >= Type::FirstDerivedTyID && !IgnoreNamedNodes) {
402 Value *ZeroInitializer = Constant::getNullValue(Typ);
404 // If we are pushing zeroinit, it will be handled below.
405 if (D != ZeroInitializer) {
406 Table[Ty].push_back(ZeroInitializer);
407 NodeMap[ZeroInitializer] = 0;
411 // Insert node into table and NodeMap...
412 unsigned DestSlot = NodeMap[D] = Table[Ty].size();
413 Table[Ty].push_back(D);
415 SC_DEBUG(" Inserting value [" << Ty << "] = " << D << " slot=" <<
417 // G = Global, C = Constant, T = Type, F = Function, o = other
418 SC_DEBUG((isa<GlobalVariable>(D) ? "G" : (isa<Constant>(D) ? "C" :
419 (isa<Type>(D) ? "T" : (isa<Function>(D) ? "F" : "o")))));
421 return (int)DestSlot;