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(Swizzle &swizzle)
 236 {
 237         visit_and_inline(swizzle.left);
 238 }
 239
 240 void FunctionInliner::visit(FunctionCall &call)
 241 {
 242         for(NodeArray<Expression>::iterator i=call.arguments.begin(); i!=call.arguments.end(); ++i)
 243                 visit_and_inline(*i);
 244
 245         FunctionDeclaration *def = call.declaration;
 246         if(def)
 247                 def = def->definition;
 248
 249         if(def && inlineable.count(def))
 250         {
 251                 string result_name = InlineContentInjector().apply(*stage, *current_function, *current_block, insert_point, *def);
 252
 253                 // This will later get removed by UnusedVariableRemover.
 254                 if(result_name.empty())
 255                         result_name = "msp_unused_from_inline";
 256
 257                 RefPtr<VariableReference> ref = new VariableReference;
 258                 ref->name = result_name;
 259                 r_inline_result = ref;
 260
 261                 /* Inlined variables need to be resolved before this function can be
 262                 inlined further. */
 263                 inlineable.erase(current_function);
 264         }
 265 }
 266
 267 void FunctionInliner::visit(ExpressionStatement &expr)
 268 {
 269         visit_and_inline(expr.expression);
 270 }
 271
 272 void FunctionInliner::visit(VariableDeclaration &var)
 273 {
 274         if(var.init_expression)
 275                 visit_and_inline(var.init_expression);
 276 }
 277
 278 void FunctionInliner::visit(FunctionDeclaration &func)
 279 {
 280         SetForScope<FunctionDeclaration *> set_func(current_function, &func);
 281         TraversingVisitor::visit(func);
 282 }
 283
 284 void FunctionInliner::visit(Conditional &cond)
 285 {
 286         visit_and_inline(cond.condition);
 287         cond.body.visit(*this);
 288 }
 289
 290 void FunctionInliner::visit(Iteration &iter)
 291 {
 292         /* Visit the initialization statement before entering the loop body so the
 293         inlined statements get inserted outside. */
 294         if(iter.init_statement)
 295                 iter.init_statement->visit(*this);
 296
 297         SetForScope<Block *> set_block(current_block, &iter.body);
 298         /* Skip the condition and loop expression parts because they're not properly
 299         inside the body block.  Inlining anything into them will require a more
 300         comprehensive transformation. */
 301         iter.body.visit(*this);
 302 }
 303
 304 void FunctionInliner::visit(Return &ret)
 305 {
 306         if(ret.expression)
 307                 visit_and_inline(ret.expression);
 308 }
 309
 310
 311 ExpressionInliner::ExpressionInfo::ExpressionInfo():
 312         expression(0),
 313         assign_scope(0),
 314         inline_point(0),
 315         inner_oper(0),
 316         outer_oper(0),
 317         inline_on_rhs(false),
 318         trivial(false),
 319         available(true)
 320 { }
 321
 322
 323 ExpressionInliner::ExpressionInliner():
 324         r_ref_info(0),
 325         r_any_inlined(false),
 326         r_trivial(false),
 327         mutating(false),
 328         iteration_init(false),
 329         iteration_body(0),
 330         r_oper(0)
 331 { }
 332
 333 bool ExpressionInliner::apply(Stage &s)
 334 {
 335         s.content.visit(*this);
 336         return r_any_inlined;
 337 }
 338
 339 void ExpressionInliner::visit_and_record(RefPtr<Expression> &ptr, const Operator *outer_oper, bool on_rhs)
 340 {
 341         r_ref_info = 0;
 342         ptr->visit(*this);
 343         if(r_ref_info && r_ref_info->expression && r_ref_info->available)
 344         {
 345                 if(iteration_body && !r_ref_info->trivial)
 346                 {
 347                         /* Don't inline non-trivial expressions which were assigned outside
 348                         an iteration statement.  The iteration may run multiple times, which
 349                         would cause the expression to also be evaluated multiple times. */
 350                         Block *i = r_ref_info->assign_scope;
 351                         for(; (i && i!=iteration_body); i=i->parent) ;
 352                         if(!i)
 353                                 return;
 354                 }
 355
 356                 r_ref_info->outer_oper = outer_oper;
 357                 if(r_ref_info->trivial)
 358                         inline_expression(*r_ref_info->expression, ptr, outer_oper, r_ref_info->inner_oper, on_rhs);
 359                 else
 360                 {
 361                         /* Record the inline point for a non-trivial expression but don't
 362                         inline it yet.  It might turn out it shouldn't be inlined after all. */
 363                         r_ref_info->inline_point = &ptr;
 364                         r_ref_info->inline_on_rhs = on_rhs;
 365                 }
 366         }
 367         r_ref_info = 0;
 368 }
 369
 370 void ExpressionInliner::inline_expression(Expression &expr, RefPtr<Expression> &ptr, const Operator *outer_oper, const Operator *inner_oper, bool on_rhs)
 371 {
 372         unsigned outer_precedence = (outer_oper ? outer_oper->precedence : 20);
 373         unsigned inner_precedence = (inner_oper ? inner_oper->precedence : 0);
 374
 375         bool needs_parentheses = (inner_precedence>=outer_precedence);
 376         if(inner_oper && inner_oper==outer_oper)
 377                 // Omit parentheses if the operator's natural grouping works out.
 378                 needs_parentheses = (inner_oper->assoc!=Operator::ASSOCIATIVE && on_rhs!=(inner_oper->assoc==Operator::RIGHT_TO_LEFT));
 379
 380         if(needs_parentheses)
 381         {
 382                 RefPtr<ParenthesizedExpression> parexpr = new ParenthesizedExpression;
 383                 parexpr->expression = expr.clone();
 384                 ptr = parexpr;
 385         }
 386         else
 387                 ptr = expr.clone();
 388
 389         r_any_inlined = true;
 390 }
 391
 392 void ExpressionInliner::visit(Block &block)
 393 {
 394         TraversingVisitor::visit(block);
 395
 396         for(map<VariableDeclaration *, ExpressionInfo>::iterator i=expressions.begin(); i!=expressions.end(); )
 397         {
 398                 map<string, VariableDeclaration *>::iterator j = block.variables.find(i->first->name);
 399                 if(j!=block.variables.end() && j->second==i->first)
 400                 {
 401                         if(i->second.expression && i->second.inline_point)
 402                                 inline_expression(*i->second.expression, *i->second.inline_point, i->second.outer_oper, i->second.inner_oper, i->second.inline_on_rhs);
 403
 404                         expressions.erase(i++);
 405                 }
 406                 else
 407                 {
 408                         /* The expression was assigned in this block and may depend on local
 409                         variables of the block.  If this is a conditionally executed block,
 410                         the assignment might not always happen.  Mark the expression as not
 411                         available to any outer blocks. */
 412                         if(i->second.assign_scope==&block)
 413                                 i->second.available = false;
 414
 415                         ++i;
 416                 }
 417         }
 418 }
 419
 420 void ExpressionInliner::visit(VariableReference &var)
 421 {
 422         if(var.declaration)
 423         {
 424                 map<VariableDeclaration *, ExpressionInfo>::iterator i = expressions.find(var.declaration);
 425                 if(i!=expressions.end())
 426                 {
 427                         /* If a non-trivial expression is referenced multiple times, don't
 428                         inline it. */
 429                         if(i->second.inline_point && !i->second.trivial)
 430                                 i->second.expression = 0;
 431                         /* Mutating expressions are analogous to self-referencing assignments
 432                         and prevent inlining. */
 433                         if(mutating)
 434                                 i->second.expression = 0;
 435                         r_ref_info = &i->second;
 436                 }
 437         }
 438 }
 439
 440 void ExpressionInliner::visit(MemberAccess &memacc)
 441 {
 442         visit_and_record(memacc.left, memacc.oper, false);
 443         r_oper = memacc.oper;
 444         r_trivial = false;
 445 }
 446
 447 void ExpressionInliner::visit(Swizzle &swizzle)
 448 {
 449         visit_and_record(swizzle.left, swizzle.oper, false);
 450         r_oper = swizzle.oper;
 451         r_trivial = false;
 452 }
 453
 454 void ExpressionInliner::visit(UnaryExpression &unary)
 455 {
 456         SetFlag set_target(mutating, mutating || unary.oper->token[1]=='+' || unary.oper->token[1]=='-');
 457         visit_and_record(unary.expression, unary.oper, false);
 458         r_oper = unary.oper;
 459         r_trivial = false;
 460 }
 461
 462 void ExpressionInliner::visit(BinaryExpression &binary)
 463 {
 464         visit_and_record(binary.left, binary.oper, false);
 465         {
 466                 SetFlag clear_target(mutating, false);
 467                 visit_and_record(binary.right, binary.oper, true);
 468         }
 469         r_oper = binary.oper;
 470         r_trivial = false;
 471 }
 472
 473 void ExpressionInliner::visit(Assignment &assign)
 474 {
 475         {
 476                 SetFlag set_target(mutating);
 477                 visit_and_record(assign.left, assign.oper, false);
 478         }
 479         r_oper = 0;
 480         visit_and_record(assign.right, assign.oper, true);
 481
 482         if(VariableDeclaration *target_var = dynamic_cast<VariableDeclaration *>(assign.target.declaration))
 483         {
 484                 map<VariableDeclaration *, ExpressionInfo>::iterator i = expressions.find(target_var);
 485                 if(i!=expressions.end())
 486                 {
 487                         /* Self-referencing assignments can't be inlined without additional
 488                         work.  Just clear any previous expression. */
 489                         i->second.expression = (assign.self_referencing ? 0 : assign.right.get());
 490                         i->second.assign_scope = current_block;
 491                         i->second.inline_point = 0;
 492                         i->second.inner_oper = r_oper;
 493                         i->second.available = true;
 494                 }
 495         }
 496
 497         r_oper = assign.oper;
 498         r_trivial = false;
 499 }
 500
 501 void ExpressionInliner::visit(FunctionCall &call)
 502 {
 503         for(NodeArray<Expression>::iterator i=call.arguments.begin(); i!=call.arguments.end(); ++i)
 504                 visit_and_record(*i, 0, false);
 505         r_oper = 0;
 506         r_trivial = false;
 507 }
 508
 509 void ExpressionInliner::visit(VariableDeclaration &var)
 510 {
 511         r_oper = 0;
 512         r_trivial = true;
 513         if(var.init_expression)
 514                 visit_and_record(var.init_expression, 0, false);
 515
 516         bool constant = var.constant;
 517         if(constant && var.layout)
 518         {
 519                 for(vector<Layout::Qualifier>::const_iterator i=var.layout->qualifiers.begin(); (constant && i!=var.layout->qualifiers.end()); ++i)
 520                         constant = (i->name!="constant_id");
 521         }
 522
 523         /* Only inline global variables if they're constant and have trivial
 524         initializers.  Non-constant variables could change in ways which are hard to
 525         analyze and non-trivial expressions could be expensive to inline.  */
 526         if((current_block->parent || (constant && r_trivial)) && var.interface.empty())
 527         {
 528                 ExpressionInfo &info = expressions[&var];
 529                 /* Assume variables declared in an iteration initialization statement
 530                 will have their values change throughout the iteration. */
 531                 info.expression = (iteration_init ? 0 : var.init_expression.get());
 532                 info.assign_scope = current_block;
 533                 info.inner_oper = r_oper;
 534                 info.trivial = r_trivial;
 535         }
 536 }
 537
 538 void ExpressionInliner::visit(Conditional &cond)
 539 {
 540         visit_and_record(cond.condition, 0, false);
 541         cond.body.visit(*this);
 542 }
 543
 544 void ExpressionInliner::visit(Iteration &iter)
 545 {
 546         SetForScope<Block *> set_block(current_block, &iter.body);
 547         if(iter.init_statement)
 548         {
 549                 SetFlag set_init(iteration_init);
 550                 iter.init_statement->visit(*this);
 551         }
 552
 553         SetForScope<Block *> set_body(iteration_body, &iter.body);
 554         if(iter.condition)
 555                 iter.condition->visit(*this);
 556         iter.body.visit(*this);
 557         if(iter.loop_expression)
 558                 iter.loop_expression->visit(*this);
 559 }
 560
 561 void ExpressionInliner::visit(Return &ret)
 562 {
 563         if(ret.expression)
 564                 visit_and_record(ret.expression, 0, false);
 565 }
 566
 567
 568 void ConstantConditionEliminator::apply(Stage &stage)
 569 {
 570         stage.content.visit(*this);
 571         NodeRemover().apply(stage, nodes_to_remove);
 572 }
 573
 574 void ConstantConditionEliminator::visit(Block &block)
 575 {
 576         SetForScope<Block *> set_block(current_block, &block);
 577         for(NodeList<Statement>::iterator i=block.body.begin(); i!=block.body.end(); ++i)
 578         {
 579                 insert_point = i;
 580                 (*i)->visit(*this);
 581         }
 582 }
 583
 584 void ConstantConditionEliminator::visit(Conditional &cond)
 585 {
 586         ExpressionEvaluator eval;
 587         cond.condition->visit(eval);
 588         if(eval.is_result_valid())
 589         {
 590                 Block &block = (eval.get_result() ? cond.body : cond.else_body);
 591                 current_block->body.splice(insert_point, block.body);
 592                 nodes_to_remove.insert(&cond);
 593                 return;
 594         }
 595
 596         TraversingVisitor::visit(cond);
 597 }
 598
 599 void ConstantConditionEliminator::visit(Iteration &iter)
 600 {
 601         if(iter.condition)
 602         {
 603                 /* If the loop condition is always false on the first iteration, the
 604                 entire loop can be removed */
 605                 ExpressionEvaluator::ValueMap values;
 606                 if(VariableDeclaration *var = dynamic_cast<VariableDeclaration *>(iter.init_statement.get()))
 607                         values[var] = var->init_expression.get();
 608                 ExpressionEvaluator eval(values);
 609                 iter.condition->visit(eval);
 610                 if(eval.is_result_valid() && !eval.get_result())
 611                 {
 612                         nodes_to_remove.insert(&iter);
 613                         return;
 614                 }
 615         }
 616
 617         TraversingVisitor::visit(iter);
 618 }
 619
 620
 621 UnusedVariableRemover::VariableInfo::VariableInfo():
 622         local(false),
 623         conditionally_assigned(false),
 624         referenced(false)
 625 { }
 626
 627
 628 bool UnusedTypeRemover::apply(Stage &stage)
 629 {
 630         stage.content.visit(*this);
 631         NodeRemover().apply(stage, unused_nodes);
 632         return !unused_nodes.empty();
 633 }
 634
 635 void UnusedTypeRemover::visit(Literal &literal)
 636 {
 637         unused_nodes.erase(literal.type);
 638 }
 639
 640 void UnusedTypeRemover::visit(UnaryExpression &unary)
 641 {
 642         unused_nodes.erase(unary.type);
 643         TraversingVisitor::visit(unary);
 644 }
 645
 646 void UnusedTypeRemover::visit(BinaryExpression &binary)
 647 {
 648         unused_nodes.erase(binary.type);
 649         TraversingVisitor::visit(binary);
 650 }
 651
 652 void UnusedTypeRemover::visit(FunctionCall &call)
 653 {
 654         unused_nodes.erase(call.type);
 655         TraversingVisitor::visit(call);
 656 }
 657
 658 void UnusedTypeRemover::visit(BasicTypeDeclaration &type)
 659 {
 660         if(type.base_type)
 661                 unused_nodes.erase(type.base_type);
 662         unused_nodes.insert(&type);
 663 }
 664
 665 void UnusedTypeRemover::visit(ImageTypeDeclaration &type)
 666 {
 667         if(type.base_type)
 668                 unused_nodes.erase(type.base_type);
 669         unused_nodes.insert(&type);
 670 }
 671
 672 void UnusedTypeRemover::visit(StructDeclaration &strct)
 673 {
 674         unused_nodes.insert(&strct);
 675         TraversingVisitor::visit(strct);
 676 }
 677
 678 void UnusedTypeRemover::visit(VariableDeclaration &var)
 679 {
 680         unused_nodes.erase(var.type_declaration);
 681 }
 682
 683 void UnusedTypeRemover::visit(InterfaceBlock &iface)
 684 {
 685         unused_nodes.erase(iface.type_declaration);
 686 }
 687
 688 void UnusedTypeRemover::visit(FunctionDeclaration &func)
 689 {
 690         unused_nodes.erase(func.return_type_declaration);
 691         TraversingVisitor::visit(func);
 692 }
 693
 694
 695 UnusedVariableRemover::UnusedVariableRemover():
 696         aggregate(0),
 697         r_assignment(0),
 698         assignment_target(false),
 699         r_assign_to_subfield(false),
 700         r_side_effects(false)
 701 { }
 702
 703 bool UnusedVariableRemover::apply(Stage &stage)
 704 {
 705         variables.push_back(BlockVariableMap());
 706         stage.content.visit(*this);
 707         BlockVariableMap &global_variables = variables.back();
 708         for(BlockVariableMap::iterator i=global_variables.begin(); i!=global_variables.end(); ++i)
 709         {
 710                 string interface = i->first->interface;
 711                 bool linked = i->first->linked_declaration;
 712                 map<VariableDeclaration *, Node *>::iterator j = aggregates.find(i->first);
 713                 if(j!=aggregates.end())
 714                         if(InterfaceBlock *iface = dynamic_cast<InterfaceBlock *>(j->second))
 715                         {
 716                                 interface = iface->interface;
 717                                 linked = iface->linked_block;
 718                         }
 719
 720                 /* Don't remove output variables which are used by the next stage or the
 721                 graphics API. */
 722                 if(interface=="out" && (stage.type==Stage::FRAGMENT || linked || !i->first->name.compare(0, 3, "gl_")))
 723                         continue;
 724
 725                 // Mark other unreferenced global variables as unused.
 726                 if(!i->second.referenced)
 727                 {
 728                         unused_nodes.insert(i->first);
 729                         clear_assignments(i->second, true);
 730                 }
 731         }
 732         variables.pop_back();
 733
 734         NodeRemover().apply(stage, unused_nodes);
 735
 736         return !unused_nodes.empty();
 737 }
 738
 739 void UnusedVariableRemover::visit(VariableReference &var)
 740 {
 741         map<VariableDeclaration *, Node *>::iterator i = aggregates.find(var.declaration);
 742         if(i!=aggregates.end())
 743                 unused_nodes.erase(i->second);
 744
 745         if(var.declaration && !assignment_target)
 746         {
 747                 VariableInfo &var_info = variables.back()[var.declaration];
 748                 // Previous assignments are used by this reference.
 749                 clear_assignments(var_info, false);
 750                 var_info.referenced = true;
 751         }
 752 }
 753
 754 void UnusedVariableRemover::visit(InterfaceBlockReference &iface)
 755 {
 756         unused_nodes.erase(iface.declaration);
 757 }
 758
 759 void UnusedVariableRemover::visit(MemberAccess &memacc)
 760 {
 761         if(assignment_target)
 762                 r_assign_to_subfield = true;
 763         TraversingVisitor::visit(memacc);
 764         unused_nodes.erase(memacc.declaration);
 765 }
 766
 767 void UnusedVariableRemover::visit(Swizzle &swizzle)
 768 {
 769         if(assignment_target)
 770                 r_assign_to_subfield = true;
 771         TraversingVisitor::visit(swizzle);
 772 }
 773
 774 void UnusedVariableRemover::visit(UnaryExpression &unary)
 775 {
 776         TraversingVisitor::visit(unary);
 777         if(unary.oper->token[1]=='+' || unary.oper->token[1]=='-')
 778                 r_side_effects = true;
 779 }
 780
 781 void UnusedVariableRemover::visit(BinaryExpression &binary)
 782 {
 783         if(binary.oper->token[0]=='[')
 784         {
 785                 if(assignment_target)
 786                         r_assign_to_subfield = true;
 787                 binary.left->visit(*this);
 788                 SetFlag set(assignment_target, false);
 789                 binary.right->visit(*this);
 790         }
 791         else
 792                 TraversingVisitor::visit(binary);
 793 }
 794
 795 void UnusedVariableRemover::visit(Assignment &assign)
 796 {
 797         {
 798                 SetFlag set(assignment_target, !assign.self_referencing);
 799                 assign.left->visit(*this);
 800         }
 801         assign.right->visit(*this);
 802         r_assignment = &assign;
 803         r_side_effects = true;
 804 }
 805
 806 void UnusedVariableRemover::visit(FunctionCall &call)
 807 {
 808         TraversingVisitor::visit(call);
 809         /* Treat function calls as having side effects so expression statements
 810         consisting of nothing but a function call won't be optimized away. */
 811         r_side_effects = true;
 812 }
 813
 814 void UnusedVariableRemover::record_assignment(VariableDeclaration &var, Node &node, bool chained)
 815 {
 816         VariableInfo &var_info = variables.back()[&var];
 817         /* An assignment which completely replaces the value of the variable causes
 818         any previous unreferenced assignments to be unused. */
 819         if(!chained)
 820                 clear_assignments(var_info, true);
 821         var_info.assignments.push_back(&node);
 822         var_info.conditionally_assigned = false;
 823 }
 824
 825 void UnusedVariableRemover::clear_assignments(VariableInfo &var_info, bool mark_unused)
 826 {
 827         if(mark_unused)
 828         {
 829                 for(vector<Node *>::iterator i=var_info.assignments.begin(); i!=var_info.assignments.end(); ++i)
 830                         unused_nodes.insert(*i);
 831         }
 832         var_info.assignments.clear();
 833 }
 834
 835 void UnusedVariableRemover::visit(ExpressionStatement &expr)
 836 {
 837         r_assignment = 0;
 838         r_assign_to_subfield = false;
 839         r_side_effects = false;
 840         TraversingVisitor::visit(expr);
 841         if(r_assignment && r_assignment->target.declaration)
 842                 if(VariableDeclaration *target_var = dynamic_cast<VariableDeclaration *>(r_assignment->target.declaration))
 843                         record_assignment(*target_var, expr, (r_assignment->self_referencing || r_assign_to_subfield));
 844         if(!r_side_effects)
 845                 unused_nodes.insert(&expr);
 846 }
 847
 848 void UnusedVariableRemover::visit(StructDeclaration &strct)
 849 {
 850         SetForScope<Node *> set(aggregate, &strct);
 851         TraversingVisitor::visit(strct);
 852 }
 853
 854 void UnusedVariableRemover::visit(VariableDeclaration &var)
 855 {
 856         if(aggregate)
 857                 aggregates[&var] = aggregate;
 858         else
 859         {
 860                 variables.back()[&var].local = true;
 861                 if(var.init_expression)
 862                         record_assignment(var, *var.init_expression, false);
 863         }
 864         TraversingVisitor::visit(var);
 865 }
 866
 867 void UnusedVariableRemover::visit(InterfaceBlock &iface)
 868 {
 869         SetForScope<Node *> set(aggregate, &iface);
 870         unused_nodes.insert(&iface);
 871         iface.struct_declaration->members.visit(*this);
 872 }
 873
 874 void UnusedVariableRemover::visit(FunctionDeclaration &func)
 875 {
 876         variables.push_back(BlockVariableMap());
 877
 878         for(NodeArray<VariableDeclaration>::iterator i=func.parameters.begin(); i!=func.parameters.end(); ++i)
 879                 (*i)->visit(*this);
 880         func.body.visit(*this);
 881
 882         BlockVariableMap &block_variables = variables.back();
 883
 884         /* Mark global variables as conditionally assigned so assignments in other
 885         functions won't be removed. */
 886         for(BlockVariableMap::iterator i=block_variables.begin(); i!=block_variables.end(); ++i)
 887                 if(!i->second.local)
 888                         i->second.conditionally_assigned = true;
 889
 890         /* Always treat function parameters as referenced.  Removing unused
 891         parameters is not currently supported. */
 892         for(NodeArray<VariableDeclaration>::iterator i=func.parameters.begin(); i!=func.parameters.end(); ++i)
 893                 block_variables[i->get()].referenced = true;
 894
 895         merge_down_variables();
 896 }
 897
 898 void UnusedVariableRemover::merge_down_variables()
 899 {
 900         BlockVariableMap &parent_variables = variables[variables.size()-2];
 901         BlockVariableMap &block_variables = variables.back();
 902         for(BlockVariableMap::iterator i=block_variables.begin(); i!=block_variables.end(); ++i)
 903         {
 904                 if(i->second.local)
 905                 {
 906                         if(!i->second.referenced)
 907                                 unused_nodes.insert(i->first);
 908                         /* Any unreferenced assignments when a variable runs out of scope
 909                         become unused. */
 910                         clear_assignments(i->second, true);
 911                         continue;
 912                 }
 913
 914                 BlockVariableMap::iterator j = parent_variables.find(i->first);
 915                 if(j==parent_variables.end())
 916                         parent_variables.insert(*i);
 917                 else
 918                 {
 919                         // Merge a non-local variable's state into the parent scope.
 920                         if(i->second.referenced || !i->second.conditionally_assigned)
 921                                 clear_assignments(j->second, !i->second.referenced);
 922                         j->second.conditionally_assigned = i->second.conditionally_assigned;
 923                         j->second.referenced |= i->second.referenced;
 924                         j->second.assignments.insert(j->second.assignments.end(), i->second.assignments.begin(), i->second.assignments.end());
 925                 }
 926         }
 927         variables.pop_back();
 928 }
 929
 930 void UnusedVariableRemover::visit(Conditional &cond)
 931 {
 932         cond.condition->visit(*this);
 933         variables.push_back(BlockVariableMap());
 934         cond.body.visit(*this);
 935
 936         BlockVariableMap if_variables;
 937         swap(variables.back(), if_variables);
 938         cond.else_body.visit(*this);
 939
 940         // Combine variables from both branches.
 941         BlockVariableMap &else_variables = variables.back();
 942         for(BlockVariableMap::iterator i=else_variables.begin(); i!=else_variables.end(); ++i)
 943         {
 944                 BlockVariableMap::iterator j = if_variables.find(i->first);
 945                 if(j!=if_variables.end())
 946                 {
 947                         // The variable was found in both branches.
 948                         i->second.assignments.insert(i->second.assignments.end(), j->second.assignments.begin(), j->second.assignments.end());
 949                         i->second.conditionally_assigned |= j->second.conditionally_assigned;
 950                         if_variables.erase(j);
 951                 }
 952                 else
 953                         // Mark variables found in only one branch as conditionally assigned.
 954                         i->second.conditionally_assigned = true;
 955         }
 956
 957         /* Move variables which were only used in the if block into the combined
 958         block. */
 959         for(BlockVariableMap::iterator i=if_variables.begin(); i!=if_variables.end(); ++i)
 960         {
 961                 i->second.conditionally_assigned = true;
 962                 else_variables.insert(*i);
 963         }
 964
 965         merge_down_variables();
 966 }
 967
 968 void UnusedVariableRemover::visit(Iteration &iter)
 969 {
 970         variables.push_back(BlockVariableMap());
 971         TraversingVisitor::visit(iter);
 972         merge_down_variables();
 973 }
 974
 975
 976 bool UnusedFunctionRemover::apply(Stage &stage)
 977 {
 978         stage.content.visit(*this);
 979         NodeRemover().apply(stage, unused_nodes);
 980         return !unused_nodes.empty();
 981 }
 982
 983 void UnusedFunctionRemover::visit(FunctionCall &call)
 984 {
 985         TraversingVisitor::visit(call);
 986
 987         unused_nodes.erase(call.declaration);
 988         if(call.declaration && call.declaration->definition!=call.declaration)
 989                 used_definitions.insert(call.declaration->definition);
 990 }
 991
 992 void UnusedFunctionRemover::visit(FunctionDeclaration &func)
 993 {
 994         TraversingVisitor::visit(func);
 995
 996         if((func.name!="main" || func.body.body.empty()) && !used_definitions.count(&func))
 997                 unused_nodes.insert(&func);
 998 }
 999
1000 } // namespace SL
1001 } // namespace GL
1002 } // namespace Msp