submodule/skia/src/sksl/transform/SkSLEliminateDeadFunctions.cpp

   1 /*
   2  * Copyright 2021 Google LLC
   3  *
   4  * Use of this source code is governed by a BSD-style license that can be
   5  * found in the LICENSE file.
   6  */
   7
   8 #include "include/private/SkSLProgramElement.h"
   9 #include "src/sksl/SkSLProgramSettings.h"
  10 #include "src/sksl/ir/SkSLFunctionDeclaration.h"
  11 #include "src/sksl/ir/SkSLFunctionDefinition.h"
  12 #include "src/sksl/ir/SkSLProgram.h"
  13 #include "src/sksl/transform/SkSLTransform.h"
  14
  15 #include <algorithm>
  16 #include <memory>
  17 #include <vector>
  18
  19 namespace SkSL {
  20
  21 bool Transform::EliminateDeadFunctions(Program& program, ProgramUsage* usage) {
  22     bool madeChanges = false;
  23
  24     if (program.fConfig->fSettings.fRemoveDeadFunctions) {
  25         auto isDeadFunction = [&](const ProgramElement* element) {
  26             if (!element->is<FunctionDefinition>()) {
  27                 return false;
  28             }
  29             const FunctionDefinition& fn = element->as<FunctionDefinition>();
  30             if (fn.declaration().isMain() || usage->get(fn.declaration()) > 0) {
  31                 return false;
  32             }
  33             usage->remove(*element);
  34             madeChanges = true;
  35             return true;
  36         };
  37
  38         program.fOwnedElements.erase(std::remove_if(program.fOwnedElements.begin(),
  39                                                     program.fOwnedElements.end(),
  40                                                     [&](const std::unique_ptr<ProgramElement>& pe) {
  41                                                         return isDeadFunction(pe.get());
  42                                                     }),
  43                                      program.fOwnedElements.end());
  44         program.fSharedElements.erase(std::remove_if(program.fSharedElements.begin(),
  45                                                      program.fSharedElements.end(),
  46                                                      isDeadFunction),
  47                                       program.fSharedElements.end());
  48     }
  49     return madeChanges;
  50 }
  51
  52 }  // namespace SkSL