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         output(false),
 624         conditionally_assigned(false),
 625         referenced(false),
 626         interface_block(0)
 627 { }
 628
 629
 630 bool UnusedTypeRemover::apply(Stage &stage)
 631 {
 632         stage.content.visit(*this);
 633         NodeRemover().apply(stage, unused_nodes);
 634         return !unused_nodes.empty();
 635 }
 636
 637 void UnusedTypeRemover::visit(Literal &literal)
 638 {
 639         unused_nodes.erase(literal.type);
 640 }
 641
 642 void UnusedTypeRemover::visit(UnaryExpression &unary)
 643 {
 644         unused_nodes.erase(unary.type);
 645         TraversingVisitor::visit(unary);
 646 }
 647
 648 void UnusedTypeRemover::visit(BinaryExpression &binary)
 649 {
 650         unused_nodes.erase(binary.type);
 651         TraversingVisitor::visit(binary);
 652 }
 653
 654 void UnusedTypeRemover::visit(FunctionCall &call)
 655 {
 656         unused_nodes.erase(call.type);
 657         TraversingVisitor::visit(call);
 658 }
 659
 660 void UnusedTypeRemover::visit(BasicTypeDeclaration &type)
 661 {
 662         if(type.base_type)
 663                 unused_nodes.erase(type.base_type);
 664         unused_nodes.insert(&type);
 665 }
 666
 667 void UnusedTypeRemover::visit(ImageTypeDeclaration &type)
 668 {
 669         if(type.base_type)
 670                 unused_nodes.erase(type.base_type);
 671         unused_nodes.insert(&type);
 672 }
 673
 674 void UnusedTypeRemover::visit(StructDeclaration &strct)
 675 {
 676         unused_nodes.insert(&strct);
 677         TraversingVisitor::visit(strct);
 678 }
 679
 680 void UnusedTypeRemover::visit(VariableDeclaration &var)
 681 {
 682         unused_nodes.erase(var.type_declaration);
 683 }
 684
 685 void UnusedTypeRemover::visit(InterfaceBlock &iface)
 686 {
 687         unused_nodes.erase(iface.type_declaration);
 688 }
 689
 690 void UnusedTypeRemover::visit(FunctionDeclaration &func)
 691 {
 692         unused_nodes.erase(func.return_type_declaration);
 693         TraversingVisitor::visit(func);
 694 }
 695
 696
 697 UnusedVariableRemover::UnusedVariableRemover():
 698         stage(0),
 699         interface_block(0),
 700         r_assignment(0),
 701         assignment_target(false),
 702         r_side_effects(false)
 703 { }
 704
 705 bool UnusedVariableRemover::apply(Stage &s)
 706 {
 707         stage = &s;
 708         variables.push_back(BlockVariableMap());
 709         s.content.visit(*this);
 710
 711         BlockVariableMap &global_variables = variables.back();
 712         set<InterfaceBlock *> used_interface_blocks;
 713         Statement *prev_decl = 0;
 714         bool output;
 715         for(BlockVariableMap::iterator i=global_variables.begin(); i!=global_variables.end(); ++i)
 716         {
 717                 if(i->first.declaration!=prev_decl)
 718                 {
 719                         prev_decl = i->first.declaration;
 720                         output = i->second.output;
 721                 }
 722                 if(output)
 723                 {
 724                         if(!i->second.assignments.empty() && i->second.interface_block)
 725                                 used_interface_blocks.insert(i->second.interface_block);
 726                         continue;
 727                 }
 728
 729                 // Mark other unreferenced global variables as unused.
 730                 if(!i->second.referenced)
 731                 {
 732                         if(!i->second.interface_block && !i->first.chain_len)
 733                                 unused_nodes.insert(i->first.declaration);
 734                         clear_assignments(i->second, true);
 735                 }
 736                 else if(i->second.interface_block)
 737                         used_interface_blocks.insert(i->second.interface_block);
 738         }
 739         variables.pop_back();
 740
 741         for(map<string, InterfaceBlock *>::const_iterator i=s.interface_blocks.begin(); i!=s.interface_blocks.end(); ++i)
 742                 if(i->second->instance_name.empty() && !used_interface_blocks.count(i->second))
 743                         unused_nodes.insert(i->second);
 744
 745         NodeRemover().apply(s, unused_nodes);
 746
 747         return !unused_nodes.empty();
 748 }
 749
 750 void UnusedVariableRemover::reference_used(Statement &declaration)
 751 {
 752         BlockVariableMap &block_vars = variables.back();
 753         /* Previous assignments of all subfields of this variable are used by
 754         this reference. */
 755         for(BlockVariableMap::iterator i=block_vars.lower_bound(&declaration); (i!=block_vars.end() && i->first.declaration==&declaration); ++i)
 756         {
 757                 clear_assignments(i->second, false);
 758                 i->second.referenced = true;
 759         }
 760
 761         // Always record a reference to the primary declaration, even if it didn't exist before
 762         block_vars[&declaration].referenced = true;
 763 }
 764
 765 void UnusedVariableRemover::visit(VariableReference &var)
 766 {
 767         if(var.declaration && !assignment_target)
 768                 reference_used(*var.declaration);
 769 }
 770
 771 void UnusedVariableRemover::visit(InterfaceBlockReference &iface)
 772 {
 773         if(iface.declaration && !assignment_target)
 774                 reference_used(*iface.declaration);
 775 }
 776
 777 void UnusedVariableRemover::visit(UnaryExpression &unary)
 778 {
 779         TraversingVisitor::visit(unary);
 780         if(unary.oper->token[1]=='+' || unary.oper->token[1]=='-')
 781                 r_side_effects = true;
 782 }
 783
 784 void UnusedVariableRemover::visit(BinaryExpression &binary)
 785 {
 786         if(binary.oper->token[0]=='[')
 787         {
 788                 binary.left->visit(*this);
 789                 SetFlag set(assignment_target, false);
 790                 binary.right->visit(*this);
 791         }
 792         else
 793                 TraversingVisitor::visit(binary);
 794 }
 795
 796 void UnusedVariableRemover::visit(Assignment &assign)
 797 {
 798         {
 799                 SetFlag set(assignment_target, !assign.self_referencing);
 800                 assign.left->visit(*this);
 801         }
 802         assign.right->visit(*this);
 803         r_assignment = &assign;
 804         r_side_effects = true;
 805 }
 806
 807 void UnusedVariableRemover::visit(FunctionCall &call)
 808 {
 809         TraversingVisitor::visit(call);
 810         /* Treat function calls as having side effects so expression statements
 811         consisting of nothing but a function call won't be optimized away. */
 812         r_side_effects = true;
 813 }
 814
 815 void UnusedVariableRemover::record_assignment(const Assignment::Target &target, Node &node, bool chained)
 816 {
 817         BlockVariableMap &block_vars = variables.back();
 818         for(BlockVariableMap::iterator i=block_vars.lower_bound(target); (i!=block_vars.end() && i->first.declaration==target.declaration); ++i)
 819         {
 820                 bool subfield = (i->first.chain_len>=target.chain_len);
 821                 for(unsigned j=0; (subfield && j<target.chain_len); ++j)
 822                         subfield = (i->first.chain[j]==target.chain[j]);
 823                 if(!subfield)
 824                         break;
 825
 826                 /* An assignment to the target causes any previous unreferenced
 827                 assignments to the same target or its subfields to be unused. */
 828                 if(!chained)
 829                         clear_assignments(i->second, true);
 830         }
 831
 832         VariableInfo &var_info = variables.back()[target];
 833         var_info.assignments.push_back(&node);
 834         var_info.conditionally_assigned = false;
 835 }
 836
 837 void UnusedVariableRemover::clear_assignments(VariableInfo &var_info, bool mark_unused)
 838 {
 839         if(mark_unused)
 840         {
 841                 for(vector<Node *>::iterator i=var_info.assignments.begin(); i!=var_info.assignments.end(); ++i)
 842                         unused_nodes.insert(*i);
 843         }
 844         var_info.assignments.clear();
 845 }
 846
 847 void UnusedVariableRemover::visit(ExpressionStatement &expr)
 848 {
 849         r_assignment = 0;
 850         r_side_effects = false;
 851         TraversingVisitor::visit(expr);
 852         if(r_assignment && r_assignment->target.declaration)
 853                 record_assignment(r_assignment->target, expr, r_assignment->self_referencing);
 854         if(!r_side_effects)
 855                 unused_nodes.insert(&expr);
 856 }
 857
 858 void UnusedVariableRemover::visit(VariableDeclaration &var)
 859 {
 860         VariableInfo &var_info = variables.back()[&var];
 861         var_info.local = true;
 862         var_info.interface_block = interface_block;
 863
 864         /* Mark variables as output if they're used by the next stage or the
 865         graphics API. */
 866         if(interface_block)
 867                 var_info.output = (interface_block->interface=="out" && (interface_block->linked_block || !interface_block->name.compare(0, 3, "gl_")));
 868         else
 869                 var_info.output = (var.interface=="out" && (stage->type==Stage::FRAGMENT || var.linked_declaration || !var.name.compare(0, 3, "gl_")));
 870
 871         if(var.init_expression)
 872                 record_assignment(&var, *var.init_expression, false);
 873         TraversingVisitor::visit(var);
 874 }
 875
 876 void UnusedVariableRemover::visit(InterfaceBlock &iface)
 877 {
 878         if(iface.instance_name.empty())
 879         {
 880                 SetForScope<InterfaceBlock *> set_block(interface_block, &iface);
 881                 iface.struct_declaration->members.visit(*this);
 882         }
 883         else
 884         {
 885                 VariableInfo &var_info = variables.back()[&iface];
 886                 var_info.local = true;
 887                 var_info.output = (iface.interface=="out" && (iface.linked_block || !iface.name.compare(0, 3, "gl_")));
 888         }
 889 }
 890
 891 void UnusedVariableRemover::visit(FunctionDeclaration &func)
 892 {
 893         variables.push_back(BlockVariableMap());
 894
 895         for(NodeArray<VariableDeclaration>::iterator i=func.parameters.begin(); i!=func.parameters.end(); ++i)
 896                 (*i)->visit(*this);
 897         func.body.visit(*this);
 898
 899         BlockVariableMap &block_variables = variables.back();
 900
 901         /* Mark global variables as conditionally assigned so assignments in other
 902         functions won't be removed. */
 903         for(BlockVariableMap::iterator i=block_variables.begin(); i!=block_variables.end(); ++i)
 904                 if(!i->second.local)
 905                         i->second.conditionally_assigned = true;
 906
 907         /* Always treat function parameters as referenced.  Removing unused
 908         parameters is not currently supported. */
 909         for(NodeArray<VariableDeclaration>::iterator i=func.parameters.begin(); i!=func.parameters.end(); ++i)
 910                 block_variables[i->get()].referenced = true;
 911
 912         merge_down_variables();
 913 }
 914
 915 void UnusedVariableRemover::merge_down_variables()
 916 {
 917         BlockVariableMap &parent_variables = variables[variables.size()-2];
 918         BlockVariableMap &block_variables = variables.back();
 919         for(BlockVariableMap::iterator i=block_variables.begin(); i!=block_variables.end(); ++i)
 920         {
 921                 if(i->second.local)
 922                 {
 923                         if(!i->second.referenced && !i->first.chain_len)
 924                                 unused_nodes.insert(i->first.declaration);
 925                         /* Any unreferenced assignments when a variable runs out of scope
 926                         become unused. */
 927                         clear_assignments(i->second, true);
 928                         continue;
 929                 }
 930
 931                 BlockVariableMap::iterator j = parent_variables.find(i->first);
 932                 if(j==parent_variables.end())
 933                         parent_variables.insert(*i);
 934                 else
 935                 {
 936                         // Merge a non-local variable's state into the parent scope.
 937                         if(i->second.referenced || !i->second.conditionally_assigned)
 938                                 clear_assignments(j->second, !i->second.referenced);
 939                         j->second.conditionally_assigned = i->second.conditionally_assigned;
 940                         j->second.referenced |= i->second.referenced;
 941                         j->second.assignments.insert(j->second.assignments.end(), i->second.assignments.begin(), i->second.assignments.end());
 942                 }
 943         }
 944         variables.pop_back();
 945 }
 946
 947 void UnusedVariableRemover::visit(Conditional &cond)
 948 {
 949         cond.condition->visit(*this);
 950         variables.push_back(BlockVariableMap());
 951         cond.body.visit(*this);
 952
 953         BlockVariableMap if_variables;
 954         swap(variables.back(), if_variables);
 955         cond.else_body.visit(*this);
 956
 957         // Combine variables from both branches.
 958         BlockVariableMap &else_variables = variables.back();
 959         for(BlockVariableMap::iterator i=else_variables.begin(); i!=else_variables.end(); ++i)
 960         {
 961                 BlockVariableMap::iterator j = if_variables.find(i->first);
 962                 if(j!=if_variables.end())
 963                 {
 964                         // The variable was found in both branches.
 965                         i->second.assignments.insert(i->second.assignments.end(), j->second.assignments.begin(), j->second.assignments.end());
 966                         i->second.conditionally_assigned |= j->second.conditionally_assigned;
 967                         if_variables.erase(j);
 968                 }
 969                 else
 970                         // Mark variables found in only one branch as conditionally assigned.
 971                         i->second.conditionally_assigned = true;
 972         }
 973
 974         /* Move variables which were only used in the if block into the combined
 975         block. */
 976         for(BlockVariableMap::iterator i=if_variables.begin(); i!=if_variables.end(); ++i)
 977         {
 978                 i->second.conditionally_assigned = true;
 979                 else_variables.insert(*i);
 980         }
 981
 982         merge_down_variables();
 983 }
 984
 985 void UnusedVariableRemover::visit(Iteration &iter)
 986 {
 987         variables.push_back(BlockVariableMap());
 988         TraversingVisitor::visit(iter);
 989         merge_down_variables();
 990 }
 991
 992
 993 bool UnusedFunctionRemover::apply(Stage &stage)
 994 {
 995         stage.content.visit(*this);
 996         NodeRemover().apply(stage, unused_nodes);
 997         return !unused_nodes.empty();
 998 }
 999
1000 void UnusedFunctionRemover::visit(FunctionCall &call)
1001 {
1002         TraversingVisitor::visit(call);
1003
1004         unused_nodes.erase(call.declaration);
1005         if(call.declaration && call.declaration->definition!=call.declaration)
1006                 used_definitions.insert(call.declaration->definition);
1007 }
1008
1009 void UnusedFunctionRemover::visit(FunctionDeclaration &func)
1010 {
1011         TraversingVisitor::visit(func);
1012
1013         if((func.name!="main" || func.body.body.empty()) && !used_definitions.count(&func))
1014                 unused_nodes.insert(&func);
1015 }
1016
1017 } // namespace SL
1018 } // namespace GL
1019 } // namespace Msp