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 }
 206
 207 void FunctionInliner::visit(Block &block)
 208 {
 209         SetForScope<Block *> set_block(current_block, &block);
 210         SetForScope<NodeList<Statement>::iterator> save_insert_point(insert_point, block.body.begin());
 211         for(NodeList<Statement>::iterator i=block.body.begin(); i!=block.body.end(); ++i)
 212         {
 213                 insert_point = i;
 214                 (*i)->visit(*this);
 215         }
 216 }
 217
 218 void FunctionInliner::visit(UnaryExpression &unary)
 219 {
 220         visit_and_inline(unary.expression);
 221         r_inline_result = 0;
 222 }
 223
 224 void FunctionInliner::visit(BinaryExpression &binary)
 225 {
 226         visit_and_inline(binary.left);
 227         visit_and_inline(binary.right);
 228         r_inline_result = 0;
 229 }
 230
 231 void FunctionInliner::visit(MemberAccess &memacc)
 232 {
 233         visit_and_inline(memacc.left);
 234         r_inline_result = 0;
 235 }
 236
 237 void FunctionInliner::visit(FunctionCall &call)
 238 {
 239         for(NodeArray<Expression>::iterator i=call.arguments.begin(); i!=call.arguments.end(); ++i)
 240                 visit_and_inline(*i);
 241
 242         FunctionDeclaration *def = call.declaration;
 243         if(def)
 244                 def = def->definition;
 245
 246         if(def && inlineable.count(def))
 247         {
 248                 string result_name = InlineContentInjector().apply(*stage, *current_function, *current_block, insert_point, *def);
 249
 250                 // This will later get removed by UnusedVariableRemover.
 251                 if(result_name.empty())
 252                         result_name = "msp_unused_from_inline";
 253
 254                 RefPtr<VariableReference> ref = new VariableReference;
 255                 ref->name = result_name;
 256                 r_inline_result = ref;
 257
 258                 /* Inlined variables need to be resolved before this function can be
 259                 inlined further. */
 260                 inlineable.erase(current_function);
 261         }
 262         else
 263                 r_inline_result = 0;
 264 }
 265
 266 void FunctionInliner::visit(ExpressionStatement &expr)
 267 {
 268         visit_and_inline(expr.expression);
 269 }
 270
 271 void FunctionInliner::visit(VariableDeclaration &var)
 272 {
 273         if(var.init_expression)
 274                 visit_and_inline(var.init_expression);
 275         r_inline_result = 0;
 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         SetForScope<Block *> set_block(current_block, &iter.body);
 293         if(iter.init_statement)
 294                 iter.init_statement->visit(*this);
 295         /* Skip the condition and loop expression parts because they're executed on
 296         every iteration of the loop */
 297         iter.body.visit(*this);
 298 }
 299
 300 void FunctionInliner::visit(Return &ret)
 301 {
 302         if(ret.expression)
 303                 visit_and_inline(ret.expression);
 304 }
 305
 306
 307 ConstantConditionEliminator::ConstantConditionEliminator():
 308         record_only(false)
 309 { }
 310
 311 void ConstantConditionEliminator::apply(Stage &stage)
 312 {
 313         stage.content.visit(*this);
 314         NodeRemover().apply(stage, nodes_to_remove);
 315 }
 316
 317 void ConstantConditionEliminator::visit(Block &block)
 318 {
 319         SetForScope<Block *> set_block(current_block, &block);
 320         for(NodeList<Statement>::iterator i=block.body.begin(); i!=block.body.end(); ++i)
 321         {
 322                 insert_point = i;
 323                 (*i)->visit(*this);
 324         }
 325
 326         for(map<string, VariableDeclaration *>::const_iterator i=block.variables.begin(); i!=block.variables.end(); ++i)
 327                 variable_values.erase(i->second);
 328 }
 329
 330 void ConstantConditionEliminator::visit(UnaryExpression &unary)
 331 {
 332         if(VariableReference *var = dynamic_cast<VariableReference *>(unary.expression.get()))
 333                 if(unary.oper->token[1]=='+' || unary.oper->token[1]=='-')
 334                         variable_values.erase(var->declaration);
 335 }
 336
 337 void ConstantConditionEliminator::visit(Assignment &assign)
 338 {
 339         variable_values.erase(assign.target_declaration);
 340 }
 341
 342 void ConstantConditionEliminator::visit(VariableDeclaration &var)
 343 {
 344         bool constant = var.constant;
 345         if(constant && var.layout)
 346         {
 347                 for(vector<Layout::Qualifier>::const_iterator i=var.layout->qualifiers.begin(); (constant && i!=var.layout->qualifiers.end()); ++i)
 348                         constant = (i->name!="constant_id");
 349         }
 350         if((constant || current_block->parent) && var.init_expression)
 351                 variable_values[&var] = var.init_expression.get();
 352 }
 353
 354 void ConstantConditionEliminator::visit(Conditional &cond)
 355 {
 356         if(!record_only)
 357         {
 358                 ExpressionEvaluator eval(variable_values);
 359                 cond.condition->visit(eval);
 360                 if(eval.is_result_valid())
 361                 {
 362                         Block &block = (eval.get_result() ? cond.body : cond.else_body);
 363                         current_block->body.splice(insert_point, block.body);
 364                         nodes_to_remove.insert(&cond);
 365                         return;
 366                 }
 367         }
 368
 369         TraversingVisitor::visit(cond);
 370 }
 371
 372 void ConstantConditionEliminator::visit(Iteration &iter)
 373 {
 374         if(!record_only)
 375         {
 376                 if(iter.condition)
 377                 {
 378                         /* If the loop condition is always false on the first iteration, the
 379                         entire loop can be removed */
 380                         if(iter.init_statement)
 381                                 iter.init_statement->visit(*this);
 382                         ExpressionEvaluator eval(variable_values);
 383                         iter.condition->visit(eval);
 384                         if(eval.is_result_valid() && !eval.get_result())
 385                         {
 386                                 nodes_to_remove.insert(&iter);
 387                                 return;
 388                         }
 389                 }
 390
 391                 /* Record all assignments that occur inside the loop body so those
 392                 variables won't be considered as constant */
 393                 SetFlag set_record(record_only);
 394                 TraversingVisitor::visit(iter);
 395         }
 396
 397         TraversingVisitor::visit(iter);
 398
 399         if(VariableDeclaration *init_decl = dynamic_cast<VariableDeclaration *>(iter.init_statement.get()))
 400                 variable_values.erase(init_decl);
 401 }
 402
 403
 404 UnusedVariableRemover::VariableInfo::VariableInfo():
 405         local(false),
 406         conditionally_assigned(false),
 407         referenced(false)
 408 { }
 409
 410
 411 UnusedVariableRemover::UnusedVariableRemover():
 412         aggregate(0),
 413         r_assignment(0),
 414         assignment_target(false),
 415         r_assign_to_subfield(false),
 416         r_side_effects(false)
 417 { }
 418
 419 bool UnusedVariableRemover::apply(Stage &stage)
 420 {
 421         variables.push_back(BlockVariableMap());
 422         stage.content.visit(*this);
 423         BlockVariableMap &global_variables = variables.back();
 424         for(BlockVariableMap::iterator i=global_variables.begin(); i!=global_variables.end(); ++i)
 425         {
 426                 /* Don't remove output variables which are used by the next stage or the
 427                 graphics API. */
 428                 if(i->first->interface=="out" && (stage.type==Stage::FRAGMENT || i->first->linked_declaration || !i->first->name.compare(0, 3, "gl_")))
 429                         continue;
 430
 431                 // Mark other unreferenced global variables as unused.
 432                 if(!i->second.referenced)
 433                 {
 434                         unused_nodes.insert(i->first);
 435                         clear_assignments(i->second, true);
 436                 }
 437         }
 438         variables.pop_back();
 439
 440         NodeRemover().apply(stage, unused_nodes);
 441
 442         return !unused_nodes.empty();
 443 }
 444
 445 void UnusedVariableRemover::visit(VariableReference &var)
 446 {
 447         map<VariableDeclaration *, Node *>::iterator i = aggregates.find(var.declaration);
 448         if(i!=aggregates.end())
 449                 unused_nodes.erase(i->second);
 450
 451         if(var.declaration && !assignment_target)
 452         {
 453                 VariableInfo &var_info = variables.back()[var.declaration];
 454                 // Previous assignments are used by this reference.
 455                 clear_assignments(var_info, false);
 456                 var_info.referenced = true;
 457         }
 458 }
 459
 460 void UnusedVariableRemover::visit(InterfaceBlockReference &iface)
 461 {
 462         unused_nodes.erase(iface.declaration);
 463 }
 464
 465 void UnusedVariableRemover::visit(MemberAccess &memacc)
 466 {
 467         r_assign_to_subfield = true;
 468         TraversingVisitor::visit(memacc);
 469         unused_nodes.erase(memacc.declaration);
 470 }
 471
 472 void UnusedVariableRemover::visit(UnaryExpression &unary)
 473 {
 474         TraversingVisitor::visit(unary);
 475         if(unary.oper->token[1]=='+' || unary.oper->token[1]=='-')
 476                 r_side_effects = true;
 477 }
 478
 479 void UnusedVariableRemover::visit(BinaryExpression &binary)
 480 {
 481         if(binary.oper->token[0]=='[')
 482         {
 483                 if(assignment_target)
 484                         r_assign_to_subfield = true;
 485                 binary.left->visit(*this);
 486                 SetFlag set(assignment_target, false);
 487                 binary.right->visit(*this);
 488         }
 489         else
 490                 TraversingVisitor::visit(binary);
 491 }
 492
 493 void UnusedVariableRemover::visit(Assignment &assign)
 494 {
 495         {
 496                 SetFlag set(assignment_target, !assign.self_referencing);
 497                 assign.left->visit(*this);
 498         }
 499         assign.right->visit(*this);
 500         r_assignment = &assign;
 501         r_side_effects = true;
 502 }
 503
 504 void UnusedVariableRemover::visit(FunctionCall &call)
 505 {
 506         TraversingVisitor::visit(call);
 507         /* Treat function calls as having side effects so expression statements
 508         consisting of nothing but a function call won't be optimized away. */
 509         r_side_effects = true;
 510 }
 511
 512 void UnusedVariableRemover::record_assignment(VariableDeclaration &var, Node &node, bool chained)
 513 {
 514         VariableInfo &var_info = variables.back()[&var];
 515         /* An assignment which completely replaces the value of the variable causes
 516         any previous unreferenced assignments to be unused. */
 517         if(!chained)
 518                 clear_assignments(var_info, true);
 519         var_info.assignments.push_back(&node);
 520         var_info.conditionally_assigned = false;
 521 }
 522
 523 void UnusedVariableRemover::clear_assignments(VariableInfo &var_info, bool mark_unused)
 524 {
 525         if(mark_unused)
 526         {
 527                 for(vector<Node *>::iterator i=var_info.assignments.begin(); i!=var_info.assignments.end(); ++i)
 528                         unused_nodes.insert(*i);
 529         }
 530         var_info.assignments.clear();
 531 }
 532
 533 void UnusedVariableRemover::visit(ExpressionStatement &expr)
 534 {
 535         r_assignment = 0;
 536         r_assign_to_subfield = false;
 537         r_side_effects = false;
 538         TraversingVisitor::visit(expr);
 539         if(r_assignment && r_assignment->target_declaration)
 540                 record_assignment(*r_assignment->target_declaration, expr, (r_assignment->self_referencing || r_assign_to_subfield));
 541         if(!r_side_effects)
 542                 unused_nodes.insert(&expr);
 543 }
 544
 545 void UnusedVariableRemover::visit(StructDeclaration &strct)
 546 {
 547         SetForScope<Node *> set(aggregate, &strct);
 548         unused_nodes.insert(&strct);
 549         TraversingVisitor::visit(strct);
 550 }
 551
 552 void UnusedVariableRemover::visit(VariableDeclaration &var)
 553 {
 554         if(aggregate)
 555                 aggregates[&var] = aggregate;
 556         else
 557         {
 558                 variables.back()[&var].local = true;
 559                 if(var.init_expression)
 560                         record_assignment(var, *var.init_expression, false);
 561         }
 562         unused_nodes.erase(var.type_declaration);
 563         TraversingVisitor::visit(var);
 564 }
 565
 566 void UnusedVariableRemover::visit(InterfaceBlock &iface)
 567 {
 568         SetForScope<Node *> set(aggregate, &iface);
 569         unused_nodes.insert(&iface);
 570         TraversingVisitor::visit(iface);
 571 }
 572
 573 void UnusedVariableRemover::visit(FunctionDeclaration &func)
 574 {
 575         variables.push_back(BlockVariableMap());
 576
 577         for(NodeArray<VariableDeclaration>::iterator i=func.parameters.begin(); i!=func.parameters.end(); ++i)
 578                 (*i)->visit(*this);
 579         func.body.visit(*this);
 580
 581         BlockVariableMap &block_variables = variables.back();
 582
 583         /* Mark global variables as conditionally assigned so assignments in other
 584         functions won't be removed. */
 585         for(BlockVariableMap::iterator i=block_variables.begin(); i!=block_variables.end(); ++i)
 586                 if(!i->second.local)
 587                         i->second.conditionally_assigned = true;
 588
 589         /* Always treat function parameters as referenced.  Removing unused
 590         parameters is not currently supported. */
 591         for(NodeArray<VariableDeclaration>::iterator i=func.parameters.begin(); i!=func.parameters.end(); ++i)
 592                 block_variables[i->get()].referenced = true;
 593
 594         merge_down_variables();
 595 }
 596
 597 void UnusedVariableRemover::merge_down_variables()
 598 {
 599         BlockVariableMap &parent_variables = variables[variables.size()-2];
 600         BlockVariableMap &block_variables = variables.back();
 601         for(BlockVariableMap::iterator i=block_variables.begin(); i!=block_variables.end(); ++i)
 602         {
 603                 if(i->second.local)
 604                 {
 605                         if(!i->second.referenced)
 606                                 unused_nodes.insert(i->first);
 607                         /* Any unreferenced assignments when a variable runs out of scope
 608                         become unused. */
 609                         clear_assignments(i->second, true);
 610                         continue;
 611                 }
 612
 613                 BlockVariableMap::iterator j = parent_variables.find(i->first);
 614                 if(j==parent_variables.end())
 615                         parent_variables.insert(*i);
 616                 else
 617                 {
 618                         // Merge a non-local variable's state into the parent scope.
 619                         if(i->second.referenced || !i->second.conditionally_assigned)
 620                                 clear_assignments(j->second, !i->second.referenced);
 621                         j->second.conditionally_assigned = i->second.conditionally_assigned;
 622                         j->second.referenced |= i->second.referenced;
 623                         j->second.assignments.insert(j->second.assignments.end(), i->second.assignments.begin(), i->second.assignments.end());
 624                 }
 625         }
 626         variables.pop_back();
 627 }
 628
 629 void UnusedVariableRemover::visit(Conditional &cond)
 630 {
 631         cond.condition->visit(*this);
 632         variables.push_back(BlockVariableMap());
 633         cond.body.visit(*this);
 634
 635         BlockVariableMap if_variables;
 636         swap(variables.back(), if_variables);
 637         cond.else_body.visit(*this);
 638
 639         // Combine variables from both branches.
 640         BlockVariableMap &else_variables = variables.back();
 641         for(BlockVariableMap::iterator i=else_variables.begin(); i!=else_variables.end(); ++i)
 642         {
 643                 BlockVariableMap::iterator j = if_variables.find(i->first);
 644                 if(j!=if_variables.end())
 645                 {
 646                         // The variable was found in both branches.
 647                         i->second.assignments.insert(i->second.assignments.end(), j->second.assignments.begin(), j->second.assignments.end());
 648                         i->second.conditionally_assigned |= j->second.conditionally_assigned;
 649                         if_variables.erase(j);
 650                 }
 651                 else
 652                         // Mark variables found in only one branch as conditionally assigned.
 653                         i->second.conditionally_assigned = true;
 654         }
 655
 656         /* Move variables which were only used in the if block into the combined
 657         block. */
 658         for(BlockVariableMap::iterator i=if_variables.begin(); i!=if_variables.end(); ++i)
 659         {
 660                 i->second.conditionally_assigned = true;
 661                 else_variables.insert(*i);
 662         }
 663
 664         merge_down_variables();
 665 }
 666
 667 void UnusedVariableRemover::visit(Iteration &iter)
 668 {
 669         variables.push_back(BlockVariableMap());
 670         TraversingVisitor::visit(iter);
 671         merge_down_variables();
 672 }
 673
 674
 675 bool UnusedFunctionRemover::apply(Stage &stage)
 676 {
 677         stage.content.visit(*this);
 678         NodeRemover().apply(stage, unused_nodes);
 679         return !unused_nodes.empty();
 680 }
 681
 682 void UnusedFunctionRemover::visit(FunctionCall &call)
 683 {
 684         TraversingVisitor::visit(call);
 685
 686         unused_nodes.erase(call.declaration);
 687         if(call.declaration && call.declaration->definition!=call.declaration)
 688                 used_definitions.insert(call.declaration->definition);
 689 }
 690
 691 void UnusedFunctionRemover::visit(FunctionDeclaration &func)
 692 {
 693         TraversingVisitor::visit(func);
 694
 695         if((func.name!="main" || func.body.body.empty()) && !used_definitions.count(&func))
 696                 unused_nodes.insert(&func);
 697 }
 698
 699 } // namespace SL
 700 } // namespace GL
 701 } // namespace Msp