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/SkSLFunctionDefinition.h"
11#include "src/sksl/ir/SkSLProgram.h"
12#include "src/sksl/transform/SkSLTransform.h"
13
14#include <algorithm>
15
16namespace SkSL {
17
18bool Transform::EliminateDeadFunctions(Program& program, ProgramUsage* usage) {
19    bool madeChanges = false;
20
21    if (program.fConfig->fSettings.fRemoveDeadFunctions) {
22        auto isDeadFunction = [&](const ProgramElement* element) {
23            if (!element->is<FunctionDefinition>()) {
24                return false;
25            }
26            const FunctionDefinition& fn = element->as<FunctionDefinition>();
27            if (fn.declaration().isMain() || usage->get(fn.declaration()) > 0) {
28                return false;
29            }
30            usage->remove(*element);
31            madeChanges = true;
32            return true;
33        };
34
35        program.fOwnedElements.erase(std::remove_if(program.fOwnedElements.begin(),
36                                                    program.fOwnedElements.end(),
37                                                    [&](const std::unique_ptr<ProgramElement>& pe) {
38                                                        return isDeadFunction(pe.get());
39                                                    }),
40                                     program.fOwnedElements.end());
41        program.fSharedElements.erase(std::remove_if(program.fSharedElements.begin(),
42                                                     program.fSharedElements.end(),
43                                                     isDeadFunction),
44                                      program.fSharedElements.end());
45    }
46    return madeChanges;
47}
48
49}  // namespace SkSL
50