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<string, VariableDeclaration *>::iterator i=block.variables.begin(); i!=block.variables.end(); ++i)
 397         {
 398                 map<Assignment::Target, ExpressionInfo>::iterator j = expressions.lower_bound(i->second);
 399                 for(; (j!=expressions.end() && j->first.declaration==i->second); )
 400                 {
 401                         if(j->second.expression && j->second.inline_point)
 402                                 inline_expression(*j->second.expression, *j->second.inline_point, j->second.outer_oper, j->second.inner_oper, j->second.inline_on_rhs);
 403
 404                         expressions.erase(j++);
 405                 }
 406         }
 407
 408         /* Expressions assigned in this block may depend on local variables of the
 409         block.  If this is a conditionally executed block, the assignments might not
 410         always happen.  Mark the expressions as not available to any outer blocks. */
 411         for(map<Assignment::Target, ExpressionInfo>::iterator i=expressions.begin(); i!=expressions.end(); ++i)
 412                 if(i->second.assign_scope==&block)
 413                         i->second.available = false;
 414 }
 415
 416 void ExpressionInliner::visit(VariableReference &var)
 417 {
 418         if(var.declaration)
 419         {
 420                 map<Assignment::Target, ExpressionInfo>::iterator i = expressions.find(var.declaration);
 421                 if(i!=expressions.end())
 422                 {
 423                         /* If a non-trivial expression is referenced multiple times, don't
 424                         inline it. */
 425                         if(i->second.inline_point && !i->second.trivial)
 426                                 i->second.expression = 0;
 427                         /* Mutating expressions are analogous to self-referencing assignments
 428                         and prevent inlining. */
 429                         if(mutating)
 430                                 i->second.expression = 0;
 431                         r_ref_info = &i->second;
 432                 }
 433         }
 434 }
 435
 436 void ExpressionInliner::visit(MemberAccess &memacc)
 437 {
 438         visit_and_record(memacc.left, memacc.oper, false);
 439         r_oper = memacc.oper;
 440         r_trivial = false;
 441 }
 442
 443 void ExpressionInliner::visit(Swizzle &swizzle)
 444 {
 445         visit_and_record(swizzle.left, swizzle.oper, false);
 446         r_oper = swizzle.oper;
 447         r_trivial = false;
 448 }
 449
 450 void ExpressionInliner::visit(UnaryExpression &unary)
 451 {
 452         SetFlag set_target(mutating, mutating || unary.oper->token[1]=='+' || unary.oper->token[1]=='-');
 453         visit_and_record(unary.expression, unary.oper, false);
 454         r_oper = unary.oper;
 455         r_trivial = false;
 456 }
 457
 458 void ExpressionInliner::visit(BinaryExpression &binary)
 459 {
 460         visit_and_record(binary.left, binary.oper, false);
 461         {
 462                 SetFlag clear_target(mutating, false);
 463                 visit_and_record(binary.right, binary.oper, true);
 464         }
 465         r_oper = binary.oper;
 466         r_trivial = false;
 467 }
 468
 469 void ExpressionInliner::visit(Assignment &assign)
 470 {
 471         {
 472                 SetFlag set_target(mutating);
 473                 visit_and_record(assign.left, assign.oper, false);
 474         }
 475         r_oper = 0;
 476         visit_and_record(assign.right, assign.oper, true);
 477
 478         map<Assignment::Target, ExpressionInfo>::iterator i = expressions.find(assign.target);
 479         if(i!=expressions.end())
 480         {
 481                 /* Self-referencing assignments can't be inlined without additional
 482                 work.  Just clear any previous expression. */
 483                 i->second.expression = (assign.self_referencing ? 0 : assign.right.get());
 484                 i->second.assign_scope = current_block;
 485                 i->second.inline_point = 0;
 486                 i->second.inner_oper = r_oper;
 487                 i->second.available = true;
 488         }
 489
 490         r_oper = assign.oper;
 491         r_trivial = false;
 492 }
 493
 494 void ExpressionInliner::visit(FunctionCall &call)
 495 {
 496         for(NodeArray<Expression>::iterator i=call.arguments.begin(); i!=call.arguments.end(); ++i)
 497                 visit_and_record(*i, 0, false);
 498         r_oper = 0;
 499         r_trivial = false;
 500 }
 501
 502 void ExpressionInliner::visit(VariableDeclaration &var)
 503 {
 504         r_oper = 0;
 505         r_trivial = true;
 506         if(var.init_expression)
 507                 visit_and_record(var.init_expression, 0, false);
 508
 509         bool constant = var.constant;
 510         if(constant && var.layout)
 511         {
 512                 for(vector<Layout::Qualifier>::const_iterator i=var.layout->qualifiers.begin(); (constant && i!=var.layout->qualifiers.end()); ++i)
 513                         constant = (i->name!="constant_id");
 514         }
 515
 516         /* Only inline global variables if they're constant and have trivial
 517         initializers.  Non-constant variables could change in ways which are hard to
 518         analyze and non-trivial expressions could be expensive to inline.  */
 519         if((current_block->parent || (constant && r_trivial)) && var.interface.empty())
 520         {
 521                 ExpressionInfo &info = expressions[&var];
 522                 /* Assume variables declared in an iteration initialization statement
 523                 will have their values change throughout the iteration. */
 524                 info.expression = (iteration_init ? 0 : var.init_expression.get());
 525                 info.assign_scope = current_block;
 526                 info.inner_oper = r_oper;
 527                 info.trivial = r_trivial;
 528         }
 529 }
 530
 531 void ExpressionInliner::visit(Conditional &cond)
 532 {
 533         visit_and_record(cond.condition, 0, false);
 534         cond.body.visit(*this);
 535 }
 536
 537 void ExpressionInliner::visit(Iteration &iter)
 538 {
 539         SetForScope<Block *> set_block(current_block, &iter.body);
 540         if(iter.init_statement)
 541         {
 542                 SetFlag set_init(iteration_init);
 543                 iter.init_statement->visit(*this);
 544         }
 545
 546         SetForScope<Block *> set_body(iteration_body, &iter.body);
 547         if(iter.condition)
 548                 iter.condition->visit(*this);
 549         iter.body.visit(*this);
 550         if(iter.loop_expression)
 551                 iter.loop_expression->visit(*this);
 552 }
 553
 554 void ExpressionInliner::visit(Return &ret)
 555 {
 556         if(ret.expression)
 557                 visit_and_record(ret.expression, 0, false);
 558 }
 559
 560
 561 void ConstantConditionEliminator::apply(Stage &stage)
 562 {
 563         stage.content.visit(*this);
 564         NodeRemover().apply(stage, nodes_to_remove);
 565 }
 566
 567 void ConstantConditionEliminator::visit(Block &block)
 568 {
 569         SetForScope<Block *> set_block(current_block, &block);
 570         for(NodeList<Statement>::iterator i=block.body.begin(); i!=block.body.end(); ++i)
 571         {
 572                 insert_point = i;
 573                 (*i)->visit(*this);
 574         }
 575 }
 576
 577 void ConstantConditionEliminator::visit(Conditional &cond)
 578 {
 579         ExpressionEvaluator eval;
 580         cond.condition->visit(eval);
 581         if(eval.is_result_valid())
 582         {
 583                 Block &block = (eval.get_result() ? cond.body : cond.else_body);
 584                 current_block->body.splice(insert_point, block.body);
 585                 nodes_to_remove.insert(&cond);
 586                 return;
 587         }
 588
 589         TraversingVisitor::visit(cond);
 590 }
 591
 592 void ConstantConditionEliminator::visit(Iteration &iter)
 593 {
 594         if(iter.condition)
 595         {
 596                 /* If the loop condition is always false on the first iteration, the
 597                 entire loop can be removed */
 598                 ExpressionEvaluator::ValueMap values;
 599                 if(VariableDeclaration *var = dynamic_cast<VariableDeclaration *>(iter.init_statement.get()))
 600                         values[var] = var->init_expression.get();
 601                 ExpressionEvaluator eval(values);
 602                 iter.condition->visit(eval);
 603                 if(eval.is_result_valid() && !eval.get_result())
 604                 {
 605                         nodes_to_remove.insert(&iter);
 606                         return;
 607                 }
 608         }
 609
 610         TraversingVisitor::visit(iter);
 611 }
 612
 613
 614 UnusedVariableRemover::VariableInfo::VariableInfo():
 615         local(false),
 616         output(false),
 617         conditionally_assigned(false),
 618         referenced(false),
 619         interface_block(0)
 620 { }
 621
 622
 623 bool UnusedTypeRemover::apply(Stage &stage)
 624 {
 625         stage.content.visit(*this);
 626         NodeRemover().apply(stage, unused_nodes);
 627         return !unused_nodes.empty();
 628 }
 629
 630 void UnusedTypeRemover::visit(Literal &literal)
 631 {
 632         unused_nodes.erase(literal.type);
 633 }
 634
 635 void UnusedTypeRemover::visit(UnaryExpression &unary)
 636 {
 637         unused_nodes.erase(unary.type);
 638         TraversingVisitor::visit(unary);
 639 }
 640
 641 void UnusedTypeRemover::visit(BinaryExpression &binary)
 642 {
 643         unused_nodes.erase(binary.type);
 644         TraversingVisitor::visit(binary);
 645 }
 646
 647 void UnusedTypeRemover::visit(FunctionCall &call)
 648 {
 649         unused_nodes.erase(call.type);
 650         TraversingVisitor::visit(call);
 651 }
 652
 653 void UnusedTypeRemover::visit(BasicTypeDeclaration &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(ImageTypeDeclaration &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(StructDeclaration &strct)
 668 {
 669         unused_nodes.insert(&strct);
 670         TraversingVisitor::visit(strct);
 671 }
 672
 673 void UnusedTypeRemover::visit(VariableDeclaration &var)
 674 {
 675         unused_nodes.erase(var.type_declaration);
 676 }
 677
 678 void UnusedTypeRemover::visit(InterfaceBlock &iface)
 679 {
 680         unused_nodes.erase(iface.type_declaration);
 681 }
 682
 683 void UnusedTypeRemover::visit(FunctionDeclaration &func)
 684 {
 685         unused_nodes.erase(func.return_type_declaration);
 686         TraversingVisitor::visit(func);
 687 }
 688
 689
 690 UnusedVariableRemover::UnusedVariableRemover():
 691         stage(0),
 692         interface_block(0),
 693         r_assignment(0),
 694         assignment_target(false),
 695         r_side_effects(false)
 696 { }
 697
 698 bool UnusedVariableRemover::apply(Stage &s)
 699 {
 700         stage = &s;
 701         variables.push_back(BlockVariableMap());
 702         s.content.visit(*this);
 703
 704         BlockVariableMap &global_variables = variables.back();
 705         set<InterfaceBlock *> used_interface_blocks;
 706         Statement *prev_decl = 0;
 707         bool output;
 708         for(BlockVariableMap::iterator i=global_variables.begin(); i!=global_variables.end(); ++i)
 709         {
 710                 if(i->first.declaration!=prev_decl)
 711                 {
 712                         prev_decl = i->first.declaration;
 713                         output = i->second.output;
 714                 }
 715                 if(output)
 716                 {
 717                         if(!i->second.assignments.empty() && i->second.interface_block)
 718                                 used_interface_blocks.insert(i->second.interface_block);
 719                         continue;
 720                 }
 721
 722                 // Mark other unreferenced global variables as unused.
 723                 if(!i->second.referenced)
 724                 {
 725                         if(!i->second.interface_block && !i->first.chain_len)
 726                                 unused_nodes.insert(i->first.declaration);
 727                         clear_assignments(i->second, true);
 728                 }
 729                 else if(i->second.interface_block)
 730                         used_interface_blocks.insert(i->second.interface_block);
 731         }
 732         variables.pop_back();
 733
 734         for(map<string, InterfaceBlock *>::const_iterator i=s.interface_blocks.begin(); i!=s.interface_blocks.end(); ++i)
 735                 if(i->second->instance_name.empty() && !used_interface_blocks.count(i->second))
 736                         unused_nodes.insert(i->second);
 737
 738         NodeRemover().apply(s, unused_nodes);
 739
 740         return !unused_nodes.empty();
 741 }
 742
 743 void UnusedVariableRemover::reference_used(Statement &declaration)
 744 {
 745         BlockVariableMap &block_vars = variables.back();
 746         /* Previous assignments of all subfields of this variable are used by
 747         this reference. */
 748         for(BlockVariableMap::iterator i=block_vars.lower_bound(&declaration); (i!=block_vars.end() && i->first.declaration==&declaration); ++i)
 749         {
 750                 clear_assignments(i->second, false);
 751                 i->second.referenced = true;
 752         }
 753
 754         // Always record a reference to the primary declaration, even if it didn't exist before
 755         block_vars[&declaration].referenced = true;
 756 }
 757
 758 void UnusedVariableRemover::visit(VariableReference &var)
 759 {
 760         if(var.declaration && !assignment_target)
 761                 reference_used(*var.declaration);
 762 }
 763
 764 void UnusedVariableRemover::visit(InterfaceBlockReference &iface)
 765 {
 766         if(iface.declaration && !assignment_target)
 767                 reference_used(*iface.declaration);
 768 }
 769
 770 void UnusedVariableRemover::visit(UnaryExpression &unary)
 771 {
 772         TraversingVisitor::visit(unary);
 773         if(unary.oper->token[1]=='+' || unary.oper->token[1]=='-')
 774                 r_side_effects = true;
 775 }
 776
 777 void UnusedVariableRemover::visit(BinaryExpression &binary)
 778 {
 779         if(binary.oper->token[0]=='[')
 780         {
 781                 binary.left->visit(*this);
 782                 SetFlag set(assignment_target, false);
 783                 binary.right->visit(*this);
 784         }
 785         else
 786                 TraversingVisitor::visit(binary);
 787 }
 788
 789 void UnusedVariableRemover::visit(Assignment &assign)
 790 {
 791         {
 792                 SetFlag set(assignment_target, !assign.self_referencing);
 793                 assign.left->visit(*this);
 794         }
 795         assign.right->visit(*this);
 796         r_assignment = &assign;
 797         r_side_effects = true;
 798 }
 799
 800 void UnusedVariableRemover::visit(FunctionCall &call)
 801 {
 802         TraversingVisitor::visit(call);
 803         /* Treat function calls as having side effects so expression statements
 804         consisting of nothing but a function call won't be optimized away. */
 805         r_side_effects = true;
 806 }
 807
 808 void UnusedVariableRemover::record_assignment(const Assignment::Target &target, Node &node, bool chained)
 809 {
 810         BlockVariableMap &block_vars = variables.back();
 811         for(BlockVariableMap::iterator i=block_vars.lower_bound(target); (i!=block_vars.end() && i->first.declaration==target.declaration); ++i)
 812         {
 813                 bool subfield = (i->first.chain_len>=target.chain_len);
 814                 for(unsigned j=0; (subfield && j<target.chain_len); ++j)
 815                         subfield = (i->first.chain[j]==target.chain[j]);
 816                 if(!subfield)
 817                         break;
 818
 819                 /* An assignment to the target causes any previous unreferenced
 820                 assignments to the same target or its subfields to be unused. */
 821                 if(!chained)
 822                         clear_assignments(i->second, true);
 823         }
 824
 825         VariableInfo &var_info = variables.back()[target];
 826         var_info.assignments.push_back(&node);
 827         var_info.conditionally_assigned = false;
 828 }
 829
 830 void UnusedVariableRemover::clear_assignments(VariableInfo &var_info, bool mark_unused)
 831 {
 832         if(mark_unused)
 833         {
 834                 for(vector<Node *>::iterator i=var_info.assignments.begin(); i!=var_info.assignments.end(); ++i)
 835                         unused_nodes.insert(*i);
 836         }
 837         var_info.assignments.clear();
 838 }
 839
 840 void UnusedVariableRemover::visit(ExpressionStatement &expr)
 841 {
 842         r_assignment = 0;
 843         r_side_effects = false;
 844         TraversingVisitor::visit(expr);
 845         if(r_assignment && r_assignment->target.declaration)
 846                 record_assignment(r_assignment->target, expr, r_assignment->self_referencing);
 847         if(!r_side_effects)
 848                 unused_nodes.insert(&expr);
 849 }
 850
 851 void UnusedVariableRemover::visit(VariableDeclaration &var)
 852 {
 853         VariableInfo &var_info = variables.back()[&var];
 854         var_info.local = true;
 855         var_info.interface_block = interface_block;
 856
 857         /* Mark variables as output if they're used by the next stage or the
 858         graphics API. */
 859         if(interface_block)
 860                 var_info.output = (interface_block->interface=="out" && (interface_block->linked_block || !interface_block->name.compare(0, 3, "gl_")));
 861         else
 862                 var_info.output = (var.interface=="out" && (stage->type==Stage::FRAGMENT || var.linked_declaration || !var.name.compare(0, 3, "gl_")));
 863
 864         if(var.init_expression)
 865                 record_assignment(&var, *var.init_expression, false);
 866         TraversingVisitor::visit(var);
 867 }
 868
 869 void UnusedVariableRemover::visit(InterfaceBlock &iface)
 870 {
 871         if(iface.instance_name.empty())
 872         {
 873                 SetForScope<InterfaceBlock *> set_block(interface_block, &iface);
 874                 iface.struct_declaration->members.visit(*this);
 875         }
 876         else
 877         {
 878                 VariableInfo &var_info = variables.back()[&iface];
 879                 var_info.local = true;
 880                 var_info.output = (iface.interface=="out" && (iface.linked_block || !iface.name.compare(0, 3, "gl_")));
 881         }
 882 }
 883
 884 void UnusedVariableRemover::visit(FunctionDeclaration &func)
 885 {
 886         variables.push_back(BlockVariableMap());
 887
 888         for(NodeArray<VariableDeclaration>::iterator i=func.parameters.begin(); i!=func.parameters.end(); ++i)
 889                 (*i)->visit(*this);
 890         func.body.visit(*this);
 891
 892         BlockVariableMap &block_variables = variables.back();
 893
 894         /* Mark global variables as conditionally assigned so assignments in other
 895         functions won't be removed. */
 896         for(BlockVariableMap::iterator i=block_variables.begin(); i!=block_variables.end(); ++i)
 897                 if(!i->second.local)
 898                         i->second.conditionally_assigned = true;
 899
 900         /* Always treat function parameters as referenced.  Removing unused
 901         parameters is not currently supported. */
 902         for(NodeArray<VariableDeclaration>::iterator i=func.parameters.begin(); i!=func.parameters.end(); ++i)
 903                 block_variables[i->get()].referenced = true;
 904
 905         merge_down_variables();
 906 }
 907
 908 void UnusedVariableRemover::merge_down_variables()
 909 {
 910         BlockVariableMap &parent_variables = variables[variables.size()-2];
 911         BlockVariableMap &block_variables = variables.back();
 912         for(BlockVariableMap::iterator i=block_variables.begin(); i!=block_variables.end(); ++i)
 913         {
 914                 if(i->second.local)
 915                 {
 916                         if(!i->second.referenced && !i->first.chain_len)
 917                                 unused_nodes.insert(i->first.declaration);
 918                         /* Any unreferenced assignments when a variable runs out of scope
 919                         become unused. */
 920                         clear_assignments(i->second, true);
 921                         continue;
 922                 }
 923
 924                 BlockVariableMap::iterator j = parent_variables.find(i->first);
 925                 if(j==parent_variables.end())
 926                         parent_variables.insert(*i);
 927                 else
 928                 {
 929                         // Merge a non-local variable's state into the parent scope.
 930                         if(i->second.referenced || !i->second.conditionally_assigned)
 931                                 clear_assignments(j->second, !i->second.referenced);
 932                         j->second.conditionally_assigned = i->second.conditionally_assigned;
 933                         j->second.referenced |= i->second.referenced;
 934                         j->second.assignments.insert(j->second.assignments.end(), i->second.assignments.begin(), i->second.assignments.end());
 935                 }
 936         }
 937         variables.pop_back();
 938 }
 939
 940 void UnusedVariableRemover::visit(Conditional &cond)
 941 {
 942         cond.condition->visit(*this);
 943         variables.push_back(BlockVariableMap());
 944         cond.body.visit(*this);
 945
 946         BlockVariableMap if_variables;
 947         swap(variables.back(), if_variables);
 948         cond.else_body.visit(*this);
 949
 950         // Combine variables from both branches.
 951         BlockVariableMap &else_variables = variables.back();
 952         for(BlockVariableMap::iterator i=else_variables.begin(); i!=else_variables.end(); ++i)
 953         {
 954                 BlockVariableMap::iterator j = if_variables.find(i->first);
 955                 if(j!=if_variables.end())
 956                 {
 957                         // The variable was found in both branches.
 958                         i->second.assignments.insert(i->second.assignments.end(), j->second.assignments.begin(), j->second.assignments.end());
 959                         i->second.conditionally_assigned |= j->second.conditionally_assigned;
 960                         if_variables.erase(j);
 961                 }
 962                 else
 963                         // Mark variables found in only one branch as conditionally assigned.
 964                         i->second.conditionally_assigned = true;
 965         }
 966
 967         /* Move variables which were only used in the if block into the combined
 968         block. */
 969         for(BlockVariableMap::iterator i=if_variables.begin(); i!=if_variables.end(); ++i)
 970         {
 971                 i->second.conditionally_assigned = true;
 972                 else_variables.insert(*i);
 973         }
 974
 975         merge_down_variables();
 976 }
 977
 978 void UnusedVariableRemover::visit(Iteration &iter)
 979 {
 980         variables.push_back(BlockVariableMap());
 981         TraversingVisitor::visit(iter);
 982         merge_down_variables();
 983 }
 984
 985
 986 bool UnusedFunctionRemover::apply(Stage &stage)
 987 {
 988         stage.content.visit(*this);
 989         NodeRemover().apply(stage, unused_nodes);
 990         return !unused_nodes.empty();
 991 }
 992
 993 void UnusedFunctionRemover::visit(FunctionCall &call)
 994 {
 995         TraversingVisitor::visit(call);
 996
 997         unused_nodes.erase(call.declaration);
 998         if(call.declaration && call.declaration->definition!=call.declaration)
 999                 used_definitions.insert(call.declaration->definition);
1000 }
1001
1002 void UnusedFunctionRemover::visit(FunctionDeclaration &func)
1003 {
1004         TraversingVisitor::visit(func);
1005
1006         if((func.name!="main" || func.body.body.empty()) && !used_definitions.count(&func))
1007                 unused_nodes.insert(&func);
1008 }
1009
1010 } // namespace SL
1011 } // namespace GL
1012 } // namespace Msp