source/glsl/optimize.cpp

   1 #include <msp/core/raii.h>
   2 #include <msp/strings/format.h>
   3 #include "optimize.h"
   4
   5 using namespace std;
   6
   7 namespace Msp {
   8 namespace GL {
   9 namespace SL {
  10
  11 InlineableFunctionLocator::InlineableFunctionLocator():
  12         current_function(0),
  13         return_count(0)
  14 { }
  15
  16 void InlineableFunctionLocator::visit(FunctionCall &call)
  17 {
  18         FunctionDeclaration *def = call.declaration;
  19         if(def)
  20                 def = def->definition;
  21
  22         if(def)
  23         {
  24                 unsigned &count = refcounts[def];
  25                 ++count;
  26                 /* Don't inline functions which are called more than once or are called
  27                 recursively. */
  28                 if(count>1 || def==current_function)
  29                         inlineable.erase(def);
  30         }
  31
  32         TraversingVisitor::visit(call);
  33 }
  34
  35 void InlineableFunctionLocator::visit(FunctionDeclaration &func)
  36 {
  37         unsigned &count = refcounts[func.definition];
  38         if(count<=1 && func.parameters.empty())
  39                 inlineable.insert(func.definition);
  40
  41         SetForScope<FunctionDeclaration *> set(current_function, &func);
  42         return_count = 0;
  43         TraversingVisitor::visit(func);
  44 }
  45
  46 void InlineableFunctionLocator::visit(Conditional &cond)
  47 {
  48         TraversingVisitor::visit(cond);
  49         inlineable.erase(current_function);
  50 }
  51
  52 void InlineableFunctionLocator::visit(Iteration &iter)
  53 {
  54         TraversingVisitor::visit(iter);
  55         inlineable.erase(current_function);
  56 }
  57
  58 void InlineableFunctionLocator::visit(Return &ret)
  59 {
  60         TraversingVisitor::visit(ret);
  61         if(return_count)
  62                 inlineable.erase(current_function);
  63         ++return_count;
  64 }
  65
  66
  67 InlineContentInjector::InlineContentInjector():
  68         source_func(0),
  69         remap_names(false),
  70         deps_only(false)
  71 { }
  72
  73 const string &InlineContentInjector::apply(Stage &stage, FunctionDeclaration &target_func, Block &tgt_blk, const NodeList<Statement>::iterator &ins_pt, FunctionDeclaration &src)
  74 {
  75         target_block = &tgt_blk;
  76         source_func = &src;
  77         for(NodeList<Statement>::iterator i=src.body.body.begin(); i!=src.body.body.end(); ++i)
  78         {
  79                 r_inlined_statement = 0;
  80                 (*i)->visit(*this);
  81                 if(!r_inlined_statement)
  82                         r_inlined_statement = (*i)->clone();
  83
  84                 SetFlag set_remap(remap_names);
  85                 r_inlined_statement->visit(*this);
  86                 tgt_blk.body.insert(ins_pt, r_inlined_statement);
  87         }
  88
  89         NodeReorderer().apply(stage, target_func, dependencies);
  90
  91         return r_result_name;
  92 }
  93
  94 string InlineContentInjector::create_unused_name(const string &base, bool always_prefix)
  95 {
  96         string result = base;
  97         if(always_prefix || target_block->variables.count(result))
  98                 result = format("_%s_%s", source_func->name, base);
  99         unsigned initial_size = result.size();
 100         for(unsigned i=1; target_block->variables.count(result); ++i)
 101         {
 102                 result.erase(initial_size);
 103                 result += format("_%d", i);
 104         }
 105         return result;
 106 }
 107
 108 void InlineContentInjector::visit(VariableReference &var)
 109 {
 110         if(remap_names)
 111         {
 112                 map<string, VariableDeclaration *>::const_iterator i = variable_map.find(var.name);
 113                 if(i!=variable_map.end())
 114                         var.name = i->second->name;
 115         }
 116         else if(var.declaration)
 117         {
 118                 SetFlag set_deps(deps_only);
 119                 dependencies.insert(var.declaration);
 120                 var.declaration->visit(*this);
 121         }
 122 }
 123
 124 void InlineContentInjector::visit(InterfaceBlockReference &iface)
 125 {
 126         if(!remap_names && iface.declaration)
 127         {
 128                 SetFlag set_deps(deps_only);
 129                 dependencies.insert(iface.declaration);
 130                 iface.declaration->visit(*this);
 131         }
 132 }
 133
 134 void InlineContentInjector::visit(FunctionCall &call)
 135 {
 136         if(!remap_names && call.declaration)
 137                 dependencies.insert(call.declaration);
 138         TraversingVisitor::visit(call);
 139 }
 140
 141 void InlineContentInjector::visit(VariableDeclaration &var)
 142 {
 143         TraversingVisitor::visit(var);
 144
 145         if(var.type_declaration)
 146         {
 147                 SetFlag set_deps(deps_only);
 148                 dependencies.insert(var.type_declaration);
 149                 var.type_declaration->visit(*this);
 150         }
 151
 152         if(!remap_names && !deps_only)
 153         {
 154                 RefPtr<VariableDeclaration> inlined_var = var.clone();
 155                 inlined_var->name = create_unused_name(var.name, false);
 156                 r_inlined_statement = inlined_var;
 157
 158                 variable_map[var.name] = inlined_var.get();
 159         }
 160 }
 161
 162 void InlineContentInjector::visit(Return &ret)
 163 {
 164         TraversingVisitor::visit(ret);
 165
 166         if(ret.expression)
 167         {
 168                 /* Create a new variable to hold the return value of the inlined
 169                 function. */
 170                 r_result_name = create_unused_name("return", true);
 171                 RefPtr<VariableDeclaration> var = new VariableDeclaration;
 172                 var->source = ret.source;
 173                 var->line = ret.line;
 174                 var->type = source_func->return_type;
 175                 var->name = r_result_name;
 176                 var->init_expression = ret.expression->clone();
 177                 r_inlined_statement = var;
 178         }
 179 }
 180
 181
 182 FunctionInliner::FunctionInliner():
 183         current_function(0),
 184         r_any_inlined(false)
 185 { }
 186
 187 bool FunctionInliner::apply(Stage &s)
 188 {
 189         stage = &s;
 190         inlineable = InlineableFunctionLocator().apply(s);
 191         r_any_inlined = false;
 192         s.content.visit(*this);
 193         return r_any_inlined;
 194 }
 195
 196 void FunctionInliner::visit_and_inline(RefPtr<Expression> &ptr)
 197 {
 198         r_inline_result = 0;
 199         ptr->visit(*this);
 200         if(r_inline_result)
 201         {
 202                 ptr = r_inline_result;
 203                 r_any_inlined = true;
 204         }
 205         r_inline_result = 0;
 206 }
 207
 208 void FunctionInliner::visit(Block &block)
 209 {
 210         SetForScope<Block *> set_block(current_block, &block);
 211         SetForScope<NodeList<Statement>::iterator> save_insert_point(insert_point, block.body.begin());
 212         for(NodeList<Statement>::iterator i=block.body.begin(); i!=block.body.end(); ++i)
 213         {
 214                 insert_point = i;
 215                 (*i)->visit(*this);
 216         }
 217 }
 218
 219 void FunctionInliner::visit(UnaryExpression &unary)
 220 {
 221         visit_and_inline(unary.expression);
 222 }
 223
 224 void FunctionInliner::visit(BinaryExpression &binary)
 225 {
 226         visit_and_inline(binary.left);
 227         visit_and_inline(binary.right);
 228 }
 229
 230 void FunctionInliner::visit(MemberAccess &memacc)
 231 {
 232         visit_and_inline(memacc.left);
 233 }
 234
 235 void FunctionInliner::visit(FunctionCall &call)
 236 {
 237         for(NodeArray<Expression>::iterator i=call.arguments.begin(); i!=call.arguments.end(); ++i)
 238                 visit_and_inline(*i);
 239
 240         FunctionDeclaration *def = call.declaration;
 241         if(def)
 242                 def = def->definition;
 243
 244         if(def && inlineable.count(def))
 245         {
 246                 string result_name = InlineContentInjector().apply(*stage, *current_function, *current_block, insert_point, *def);
 247
 248                 // This will later get removed by UnusedVariableRemover.
 249                 if(result_name.empty())
 250                         result_name = "msp_unused_from_inline";
 251
 252                 RefPtr<VariableReference> ref = new VariableReference;
 253                 ref->name = result_name;
 254                 r_inline_result = ref;
 255
 256                 /* Inlined variables need to be resolved before this function can be
 257                 inlined further. */
 258                 inlineable.erase(current_function);
 259         }
 260 }
 261
 262 void FunctionInliner::visit(ExpressionStatement &expr)
 263 {
 264         visit_and_inline(expr.expression);
 265 }
 266
 267 void FunctionInliner::visit(VariableDeclaration &var)
 268 {
 269         if(var.init_expression)
 270                 visit_and_inline(var.init_expression);
 271 }
 272
 273 void FunctionInliner::visit(FunctionDeclaration &func)
 274 {
 275         SetForScope<FunctionDeclaration *> set_func(current_function, &func);
 276         TraversingVisitor::visit(func);
 277 }
 278
 279 void FunctionInliner::visit(Conditional &cond)
 280 {
 281         visit_and_inline(cond.condition);
 282         cond.body.visit(*this);
 283 }
 284
 285 void FunctionInliner::visit(Iteration &iter)
 286 {
 287         /* Visit the initialization statement before entering the loop body so the
 288         inlined statements get inserted outside. */
 289         if(iter.init_statement)
 290                 iter.init_statement->visit(*this);
 291
 292         SetForScope<Block *> set_block(current_block, &iter.body);
 293         /* Skip the condition and loop expression parts because they're not properly
 294         inside the body block.  Inlining anything into them will require a more
 295         comprehensive transformation. */
 296         iter.body.visit(*this);
 297 }
 298
 299 void FunctionInliner::visit(Return &ret)
 300 {
 301         if(ret.expression)
 302                 visit_and_inline(ret.expression);
 303 }
 304
 305
 306 ExpressionInliner::ExpressionInfo::ExpressionInfo():
 307         expression(0),
 308         assign_scope(0),
 309         inline_point(0),
 310         inner_oper(0),
 311         outer_oper(0),
 312         inline_on_rhs(false),
 313         trivial(false),
 314         available(true)
 315 { }
 316
 317
 318 ExpressionInliner::ExpressionInliner():
 319         r_ref_info(0),
 320         r_any_inlined(false),
 321         r_trivial(false),
 322         mutating(false),
 323         iteration_init(false),
 324         iteration_body(0),
 325         r_oper(0)
 326 { }
 327
 328 bool ExpressionInliner::apply(Stage &s)
 329 {
 330         s.content.visit(*this);
 331         return r_any_inlined;
 332 }
 333
 334 void ExpressionInliner::visit_and_record(RefPtr<Expression> &ptr, const Operator *outer_oper, bool on_rhs)
 335 {
 336         r_ref_info = 0;
 337         ptr->visit(*this);
 338         if(r_ref_info && r_ref_info->expression && r_ref_info->available)
 339         {
 340                 if(iteration_body && !r_ref_info->trivial)
 341                 {
 342                         /* Don't inline non-trivial expressions which were assigned outside
 343                         an iteration statement.  The iteration may run multiple times, which
 344                         would cause the expression to also be evaluated multiple times. */
 345                         Block *i = r_ref_info->assign_scope;
 346                         for(; (i && i!=iteration_body); i=i->parent) ;
 347                         if(!i)
 348                                 return;
 349                 }
 350
 351                 r_ref_info->outer_oper = outer_oper;
 352                 if(r_ref_info->trivial)
 353                         inline_expression(*r_ref_info->expression, ptr, outer_oper, r_ref_info->inner_oper, on_rhs);
 354                 else
 355                 {
 356                         /* Record the inline point for a non-trivial expression but don't
 357                         inline it yet.  It might turn out it shouldn't be inlined after all. */
 358                         r_ref_info->inline_point = &ptr;
 359                         r_ref_info->inline_on_rhs = on_rhs;
 360                 }
 361         }
 362         r_ref_info = 0;
 363 }
 364
 365 void ExpressionInliner::inline_expression(Expression &expr, RefPtr<Expression> &ptr, const Operator *outer_oper, const Operator *inner_oper, bool on_rhs)
 366 {
 367         unsigned outer_precedence = (outer_oper ? outer_oper->precedence : 20);
 368         unsigned inner_precedence = (inner_oper ? inner_oper->precedence : 0);
 369
 370         bool needs_parentheses = (inner_precedence>=outer_precedence);
 371         if(inner_oper && inner_oper==outer_oper)
 372                 // Omit parentheses if the operator's natural grouping works out.
 373                 needs_parentheses = (inner_oper->assoc!=Operator::ASSOCIATIVE && on_rhs!=(inner_oper->assoc==Operator::RIGHT_TO_LEFT));
 374
 375         if(needs_parentheses)
 376         {
 377                 RefPtr<ParenthesizedExpression> parexpr = new ParenthesizedExpression;
 378                 parexpr->expression = expr.clone();
 379                 ptr = parexpr;
 380         }
 381         else
 382                 ptr = expr.clone();
 383
 384         r_any_inlined = true;
 385 }
 386
 387 void ExpressionInliner::visit(Block &block)
 388 {
 389         TraversingVisitor::visit(block);
 390
 391         for(map<VariableDeclaration *, ExpressionInfo>::iterator i=expressions.begin(); i!=expressions.end(); )
 392         {
 393                 map<string, VariableDeclaration *>::iterator j = block.variables.find(i->first->name);
 394                 if(j!=block.variables.end() && j->second==i->first)
 395                 {
 396                         if(i->second.expression && i->second.inline_point)
 397                                 inline_expression(*i->second.expression, *i->second.inline_point, i->second.outer_oper, i->second.inner_oper, i->second.inline_on_rhs);
 398
 399                         expressions.erase(i++);
 400                 }
 401                 else
 402                 {
 403                         /* The expression was assigned in this block and may depend on local
 404                         variables of the block.  If this is a conditionally executed block,
 405                         the assignment might not always happen.  Mark the expression as not
 406                         available to any outer blocks. */
 407                         if(i->second.assign_scope==&block)
 408                                 i->second.available = false;
 409
 410                         ++i;
 411                 }
 412         }
 413 }
 414
 415 void ExpressionInliner::visit(VariableReference &var)
 416 {
 417         if(var.declaration)
 418         {
 419                 map<VariableDeclaration *, ExpressionInfo>::iterator i = expressions.find(var.declaration);
 420                 if(i!=expressions.end())
 421                 {
 422                         /* If a non-trivial expression is referenced multiple times, don't
 423                         inline it. */
 424                         if(i->second.inline_point && !i->second.trivial)
 425                                 i->second.expression = 0;
 426                         /* Mutating expressions are analogous to self-referencing assignments
 427                         and prevent inlining. */
 428                         if(mutating)
 429                                 i->second.expression = 0;
 430                         r_ref_info = &i->second;
 431                 }
 432         }
 433 }
 434
 435 void ExpressionInliner::visit(MemberAccess &memacc)
 436 {
 437         visit_and_record(memacc.left, memacc.oper, false);
 438         r_oper = memacc.oper;
 439         r_trivial = false;
 440 }
 441
 442 void ExpressionInliner::visit(UnaryExpression &unary)
 443 {
 444         SetFlag set_target(mutating, mutating || unary.oper->token[1]=='+' || unary.oper->token[1]=='-');
 445         visit_and_record(unary.expression, unary.oper, false);
 446         r_oper = unary.oper;
 447         r_trivial = false;
 448 }
 449
 450 void ExpressionInliner::visit(BinaryExpression &binary)
 451 {
 452         visit_and_record(binary.left, binary.oper, false);
 453         {
 454                 SetFlag clear_target(mutating, false);
 455                 visit_and_record(binary.right, binary.oper, true);
 456         }
 457         r_oper = binary.oper;
 458         r_trivial = false;
 459 }
 460
 461 void ExpressionInliner::visit(Assignment &assign)
 462 {
 463         {
 464                 SetFlag set_target(mutating);
 465                 visit_and_record(assign.left, assign.oper, false);
 466         }
 467         r_oper = 0;
 468         visit_and_record(assign.right, assign.oper, true);
 469
 470         if(assign.target_declaration)
 471         {
 472                 map<VariableDeclaration *, ExpressionInfo>::iterator i = expressions.find(assign.target_declaration);
 473                 if(i!=expressions.end())
 474                 {
 475                         /* Self-referencing assignments can't be inlined without additional
 476                         work.  Just clear any previous expression. */
 477                         i->second.expression = (assign.self_referencing ? 0 : assign.right.get());
 478                         i->second.assign_scope = current_block;
 479                         i->second.inline_point = 0;
 480                         i->second.inner_oper = r_oper;
 481                         i->second.available = true;
 482                 }
 483         }
 484
 485         r_oper = assign.oper;
 486         r_trivial = false;
 487 }
 488
 489 void ExpressionInliner::visit(FunctionCall &call)
 490 {
 491         for(NodeArray<Expression>::iterator i=call.arguments.begin(); i!=call.arguments.end(); ++i)
 492                 visit_and_record(*i, 0, false);
 493         r_oper = 0;
 494         r_trivial = false;
 495 }
 496
 497 void ExpressionInliner::visit(VariableDeclaration &var)
 498 {
 499         r_oper = 0;
 500         r_trivial = true;
 501         if(var.init_expression)
 502                 visit_and_record(var.init_expression, 0, false);
 503
 504         bool constant = var.constant;
 505         if(constant && var.layout)
 506         {
 507                 for(vector<Layout::Qualifier>::const_iterator i=var.layout->qualifiers.begin(); (constant && i!=var.layout->qualifiers.end()); ++i)
 508                         constant = (i->name!="constant_id");
 509         }
 510
 511         /* Only inline global variables if they're constant and have trivial
 512         initializers.  Non-constant variables could change in ways which are hard to
 513         analyze and non-trivial expressions could be expensive to inline.  */
 514         if((current_block->parent || (constant && r_trivial)) && var.interface.empty())
 515         {
 516                 ExpressionInfo &info = expressions[&var];
 517                 /* Assume variables declared in an iteration initialization statement
 518                 will have their values change throughout the iteration. */
 519                 info.expression = (iteration_init ? 0 : var.init_expression.get());
 520                 info.assign_scope = current_block;
 521                 info.inner_oper = r_oper;
 522                 info.trivial = r_trivial;
 523         }
 524 }
 525
 526 void ExpressionInliner::visit(Conditional &cond)
 527 {
 528         visit_and_record(cond.condition, 0, false);
 529         cond.body.visit(*this);
 530 }
 531
 532 void ExpressionInliner::visit(Iteration &iter)
 533 {
 534         SetForScope<Block *> set_block(current_block, &iter.body);
 535         if(iter.init_statement)
 536         {
 537                 SetFlag set_init(iteration_init);
 538                 iter.init_statement->visit(*this);
 539         }
 540
 541         SetForScope<Block *> set_body(iteration_body, &iter.body);
 542         if(iter.condition)
 543                 iter.condition->visit(*this);
 544         iter.body.visit(*this);
 545         if(iter.loop_expression)
 546                 iter.loop_expression->visit(*this);
 547 }
 548
 549 void ExpressionInliner::visit(Return &ret)
 550 {
 551         if(ret.expression)
 552                 visit_and_record(ret.expression, 0, false);
 553 }
 554
 555
 556 void ConstantConditionEliminator::apply(Stage &stage)
 557 {
 558         stage.content.visit(*this);
 559         NodeRemover().apply(stage, nodes_to_remove);
 560 }
 561
 562 void ConstantConditionEliminator::visit(Block &block)
 563 {
 564         SetForScope<Block *> set_block(current_block, &block);
 565         for(NodeList<Statement>::iterator i=block.body.begin(); i!=block.body.end(); ++i)
 566         {
 567                 insert_point = i;
 568                 (*i)->visit(*this);
 569         }
 570 }
 571
 572 void ConstantConditionEliminator::visit(Conditional &cond)
 573 {
 574         ExpressionEvaluator eval;
 575         cond.condition->visit(eval);
 576         if(eval.is_result_valid())
 577         {
 578                 Block &block = (eval.get_result() ? cond.body : cond.else_body);
 579                 current_block->body.splice(insert_point, block.body);
 580                 nodes_to_remove.insert(&cond);
 581                 return;
 582         }
 583
 584         TraversingVisitor::visit(cond);
 585 }
 586
 587 void ConstantConditionEliminator::visit(Iteration &iter)
 588 {
 589         if(iter.condition)
 590         {
 591                 /* If the loop condition is always false on the first iteration, the
 592                 entire loop can be removed */
 593                 ExpressionEvaluator::ValueMap values;
 594                 if(VariableDeclaration *var = dynamic_cast<VariableDeclaration *>(iter.init_statement.get()))
 595                         values[var] = var->init_expression.get();
 596                 ExpressionEvaluator eval(values);
 597                 iter.condition->visit(eval);
 598                 if(eval.is_result_valid() && !eval.get_result())
 599                 {
 600                         nodes_to_remove.insert(&iter);
 601                         return;
 602                 }
 603         }
 604
 605         TraversingVisitor::visit(iter);
 606 }
 607
 608
 609 UnusedVariableRemover::VariableInfo::VariableInfo():
 610         local(false),
 611         conditionally_assigned(false),
 612         referenced(false)
 613 { }
 614
 615
 616 bool UnusedTypeRemover::apply(Stage &stage)
 617 {
 618         stage.content.visit(*this);
 619         NodeRemover().apply(stage, unused_nodes);
 620         return !unused_nodes.empty();
 621 }
 622
 623 void UnusedTypeRemover::visit(Literal &literal)
 624 {
 625         unused_nodes.erase(literal.type);
 626 }
 627
 628 void UnusedTypeRemover::visit(UnaryExpression &unary)
 629 {
 630         unused_nodes.erase(unary.type);
 631         TraversingVisitor::visit(unary);
 632 }
 633
 634 void UnusedTypeRemover::visit(BinaryExpression &binary)
 635 {
 636         unused_nodes.erase(binary.type);
 637         TraversingVisitor::visit(binary);
 638 }
 639
 640 void UnusedTypeRemover::visit(FunctionCall &call)
 641 {
 642         unused_nodes.erase(call.type);
 643         TraversingVisitor::visit(call);
 644 }
 645
 646 void UnusedTypeRemover::visit(BasicTypeDeclaration &type)
 647 {
 648         if(type.base_type)
 649                 unused_nodes.erase(type.base_type);
 650         unused_nodes.insert(&type);
 651 }
 652
 653 void UnusedTypeRemover::visit(ImageTypeDeclaration &type)
 654 {
 655         if(type.base_type)
 656                 unused_nodes.erase(type.base_type);
 657         unused_nodes.insert(&type);
 658 }
 659
 660 void UnusedTypeRemover::visit(StructDeclaration &strct)
 661 {
 662         unused_nodes.insert(&strct);
 663         TraversingVisitor::visit(strct);
 664 }
 665
 666 void UnusedTypeRemover::visit(VariableDeclaration &var)
 667 {
 668         unused_nodes.erase(var.type_declaration);
 669 }
 670
 671 void UnusedTypeRemover::visit(InterfaceBlock &iface)
 672 {
 673         unused_nodes.erase(iface.type_declaration);
 674 }
 675
 676 void UnusedTypeRemover::visit(FunctionDeclaration &func)
 677 {
 678         unused_nodes.erase(func.return_type_declaration);
 679         TraversingVisitor::visit(func);
 680 }
 681
 682
 683 UnusedVariableRemover::UnusedVariableRemover():
 684         aggregate(0),
 685         r_assignment(0),
 686         assignment_target(false),
 687         r_assign_to_subfield(false),
 688         r_side_effects(false)
 689 { }
 690
 691 bool UnusedVariableRemover::apply(Stage &stage)
 692 {
 693         variables.push_back(BlockVariableMap());
 694         stage.content.visit(*this);
 695         BlockVariableMap &global_variables = variables.back();
 696         for(BlockVariableMap::iterator i=global_variables.begin(); i!=global_variables.end(); ++i)
 697         {
 698                 string interface = i->first->interface;
 699                 bool linked = i->first->linked_declaration;
 700                 map<VariableDeclaration *, Node *>::iterator j = aggregates.find(i->first);
 701                 if(j!=aggregates.end())
 702                         if(InterfaceBlock *iface = dynamic_cast<InterfaceBlock *>(j->second))
 703                         {
 704                                 interface = iface->interface;
 705                                 linked = iface->linked_block;
 706                         }
 707
 708                 /* Don't remove output variables which are used by the next stage or the
 709                 graphics API. */
 710                 if(interface=="out" && (stage.type==Stage::FRAGMENT || linked || !i->first->name.compare(0, 3, "gl_")))
 711                         continue;
 712
 713                 // Mark other unreferenced global variables as unused.
 714                 if(!i->second.referenced)
 715                 {
 716                         unused_nodes.insert(i->first);
 717                         clear_assignments(i->second, true);
 718                 }
 719         }
 720         variables.pop_back();
 721
 722         NodeRemover().apply(stage, unused_nodes);
 723
 724         return !unused_nodes.empty();
 725 }
 726
 727 void UnusedVariableRemover::visit(VariableReference &var)
 728 {
 729         map<VariableDeclaration *, Node *>::iterator i = aggregates.find(var.declaration);
 730         if(i!=aggregates.end())
 731                 unused_nodes.erase(i->second);
 732
 733         if(var.declaration && !assignment_target)
 734         {
 735                 VariableInfo &var_info = variables.back()[var.declaration];
 736                 // Previous assignments are used by this reference.
 737                 clear_assignments(var_info, false);
 738                 var_info.referenced = true;
 739         }
 740 }
 741
 742 void UnusedVariableRemover::visit(InterfaceBlockReference &iface)
 743 {
 744         unused_nodes.erase(iface.declaration);
 745 }
 746
 747 void UnusedVariableRemover::visit(MemberAccess &memacc)
 748 {
 749         if(assignment_target)
 750                 r_assign_to_subfield = true;
 751         TraversingVisitor::visit(memacc);
 752         unused_nodes.erase(memacc.declaration);
 753 }
 754
 755 void UnusedVariableRemover::visit(UnaryExpression &unary)
 756 {
 757         TraversingVisitor::visit(unary);
 758         if(unary.oper->token[1]=='+' || unary.oper->token[1]=='-')
 759                 r_side_effects = true;
 760 }
 761
 762 void UnusedVariableRemover::visit(BinaryExpression &binary)
 763 {
 764         if(binary.oper->token[0]=='[')
 765         {
 766                 if(assignment_target)
 767                         r_assign_to_subfield = true;
 768                 binary.left->visit(*this);
 769                 SetFlag set(assignment_target, false);
 770                 binary.right->visit(*this);
 771         }
 772         else
 773                 TraversingVisitor::visit(binary);
 774 }
 775
 776 void UnusedVariableRemover::visit(Assignment &assign)
 777 {
 778         {
 779                 SetFlag set(assignment_target, !assign.self_referencing);
 780                 assign.left->visit(*this);
 781         }
 782         assign.right->visit(*this);
 783         r_assignment = &assign;
 784         r_side_effects = true;
 785 }
 786
 787 void UnusedVariableRemover::visit(FunctionCall &call)
 788 {
 789         TraversingVisitor::visit(call);
 790         /* Treat function calls as having side effects so expression statements
 791         consisting of nothing but a function call won't be optimized away. */
 792         r_side_effects = true;
 793 }
 794
 795 void UnusedVariableRemover::record_assignment(VariableDeclaration &var, Node &node, bool chained)
 796 {
 797         VariableInfo &var_info = variables.back()[&var];
 798         /* An assignment which completely replaces the value of the variable causes
 799         any previous unreferenced assignments to be unused. */
 800         if(!chained)
 801                 clear_assignments(var_info, true);
 802         var_info.assignments.push_back(&node);
 803         var_info.conditionally_assigned = false;
 804 }
 805
 806 void UnusedVariableRemover::clear_assignments(VariableInfo &var_info, bool mark_unused)
 807 {
 808         if(mark_unused)
 809         {
 810                 for(vector<Node *>::iterator i=var_info.assignments.begin(); i!=var_info.assignments.end(); ++i)
 811                         unused_nodes.insert(*i);
 812         }
 813         var_info.assignments.clear();
 814 }
 815
 816 void UnusedVariableRemover::visit(ExpressionStatement &expr)
 817 {
 818         r_assignment = 0;
 819         r_assign_to_subfield = false;
 820         r_side_effects = false;
 821         TraversingVisitor::visit(expr);
 822         if(r_assignment && r_assignment->target_declaration)
 823                 record_assignment(*r_assignment->target_declaration, expr, (r_assignment->self_referencing || r_assign_to_subfield));
 824         if(!r_side_effects)
 825                 unused_nodes.insert(&expr);
 826 }
 827
 828 void UnusedVariableRemover::visit(StructDeclaration &strct)
 829 {
 830         SetForScope<Node *> set(aggregate, &strct);
 831         TraversingVisitor::visit(strct);
 832 }
 833
 834 void UnusedVariableRemover::visit(VariableDeclaration &var)
 835 {
 836         if(aggregate)
 837                 aggregates[&var] = aggregate;
 838         else
 839         {
 840                 variables.back()[&var].local = true;
 841                 if(var.init_expression)
 842                         record_assignment(var, *var.init_expression, false);
 843         }
 844         TraversingVisitor::visit(var);
 845 }
 846
 847 void UnusedVariableRemover::visit(InterfaceBlock &iface)
 848 {
 849         SetForScope<Node *> set(aggregate, &iface);
 850         unused_nodes.insert(&iface);
 851         iface.struct_declaration->members.visit(*this);
 852 }
 853
 854 void UnusedVariableRemover::visit(FunctionDeclaration &func)
 855 {
 856         variables.push_back(BlockVariableMap());
 857
 858         for(NodeArray<VariableDeclaration>::iterator i=func.parameters.begin(); i!=func.parameters.end(); ++i)
 859                 (*i)->visit(*this);
 860         func.body.visit(*this);
 861
 862         BlockVariableMap &block_variables = variables.back();
 863
 864         /* Mark global variables as conditionally assigned so assignments in other
 865         functions won't be removed. */
 866         for(BlockVariableMap::iterator i=block_variables.begin(); i!=block_variables.end(); ++i)
 867                 if(!i->second.local)
 868                         i->second.conditionally_assigned = true;
 869
 870         /* Always treat function parameters as referenced.  Removing unused
 871         parameters is not currently supported. */
 872         for(NodeArray<VariableDeclaration>::iterator i=func.parameters.begin(); i!=func.parameters.end(); ++i)
 873                 block_variables[i->get()].referenced = true;
 874
 875         merge_down_variables();
 876 }
 877
 878 void UnusedVariableRemover::merge_down_variables()
 879 {
 880         BlockVariableMap &parent_variables = variables[variables.size()-2];
 881         BlockVariableMap &block_variables = variables.back();
 882         for(BlockVariableMap::iterator i=block_variables.begin(); i!=block_variables.end(); ++i)
 883         {
 884                 if(i->second.local)
 885                 {
 886                         if(!i->second.referenced)
 887                                 unused_nodes.insert(i->first);
 888                         /* Any unreferenced assignments when a variable runs out of scope
 889                         become unused. */
 890                         clear_assignments(i->second, true);
 891                         continue;
 892                 }
 893
 894                 BlockVariableMap::iterator j = parent_variables.find(i->first);
 895                 if(j==parent_variables.end())
 896                         parent_variables.insert(*i);
 897                 else
 898                 {
 899                         // Merge a non-local variable's state into the parent scope.
 900                         if(i->second.referenced || !i->second.conditionally_assigned)
 901                                 clear_assignments(j->second, !i->second.referenced);
 902                         j->second.conditionally_assigned = i->second.conditionally_assigned;
 903                         j->second.referenced |= i->second.referenced;
 904                         j->second.assignments.insert(j->second.assignments.end(), i->second.assignments.begin(), i->second.assignments.end());
 905                 }
 906         }
 907         variables.pop_back();
 908 }
 909
 910 void UnusedVariableRemover::visit(Conditional &cond)
 911 {
 912         cond.condition->visit(*this);
 913         variables.push_back(BlockVariableMap());
 914         cond.body.visit(*this);
 915
 916         BlockVariableMap if_variables;
 917         swap(variables.back(), if_variables);
 918         cond.else_body.visit(*this);
 919
 920         // Combine variables from both branches.
 921         BlockVariableMap &else_variables = variables.back();
 922         for(BlockVariableMap::iterator i=else_variables.begin(); i!=else_variables.end(); ++i)
 923         {
 924                 BlockVariableMap::iterator j = if_variables.find(i->first);
 925                 if(j!=if_variables.end())
 926                 {
 927                         // The variable was found in both branches.
 928                         i->second.assignments.insert(i->second.assignments.end(), j->second.assignments.begin(), j->second.assignments.end());
 929                         i->second.conditionally_assigned |= j->second.conditionally_assigned;
 930                         if_variables.erase(j);
 931                 }
 932                 else
 933                         // Mark variables found in only one branch as conditionally assigned.
 934                         i->second.conditionally_assigned = true;
 935         }
 936
 937         /* Move variables which were only used in the if block into the combined
 938         block. */
 939         for(BlockVariableMap::iterator i=if_variables.begin(); i!=if_variables.end(); ++i)
 940         {
 941                 i->second.conditionally_assigned = true;
 942                 else_variables.insert(*i);
 943         }
 944
 945         merge_down_variables();
 946 }
 947
 948 void UnusedVariableRemover::visit(Iteration &iter)
 949 {
 950         variables.push_back(BlockVariableMap());
 951         TraversingVisitor::visit(iter);
 952         merge_down_variables();
 953 }
 954
 955
 956 bool UnusedFunctionRemover::apply(Stage &stage)
 957 {
 958         stage.content.visit(*this);
 959         NodeRemover().apply(stage, unused_nodes);
 960         return !unused_nodes.empty();
 961 }
 962
 963 void UnusedFunctionRemover::visit(FunctionCall &call)
 964 {
 965         TraversingVisitor::visit(call);
 966
 967         unused_nodes.erase(call.declaration);
 968         if(call.declaration && call.declaration->definition!=call.declaration)
 969                 used_definitions.insert(call.declaration->definition);
 970 }
 971
 972 void UnusedFunctionRemover::visit(FunctionDeclaration &func)
 973 {
 974         TraversingVisitor::visit(func);
 975
 976         if((func.name!="main" || func.body.body.empty()) && !used_definitions.count(&func))
 977                 unused_nodes.insert(&func);
 978 }
 979
 980 } // namespace SL
 981 } // namespace GL
 982 } // namespace Msp