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// Copyright 2022 The Tint Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "src/tint/transform/while_to_loop.h"
#include <utility>
#include "src/tint/ast/break_statement.h"
#include "src/tint/program_builder.h"
TINT_INSTANTIATE_TYPEINFO(tint::transform::WhileToLoop);
namespace tint::transform {
namespace {
bool ShouldRun(const Program* program) {
for (auto* node : program->ASTNodes().Objects()) {
if (node->Is<ast::WhileStatement>()) {
return true;
}
}
return false;
}
} // namespace
WhileToLoop::WhileToLoop() = default;
WhileToLoop::~WhileToLoop() = default;
Transform::ApplyResult WhileToLoop::Apply(const Program* src, const DataMap&, DataMap&) const {
if (!ShouldRun(src)) {
return SkipTransform;
}
ProgramBuilder b;
CloneContext ctx{&b, src, /* auto_clone_symbols */ true};
ctx.ReplaceAll([&](const ast::WhileStatement* w) -> const ast::Statement* {
utils::Vector<const ast::Statement*, 16> stmts;
auto* cond = w->condition;
// !condition
auto* not_cond = b.Not(ctx.Clone(cond));
// { break; }
auto* break_body = b.Block(b.Break());
// if (!condition) { break; }
stmts.Push(b.If(not_cond, break_body));
for (auto* stmt : w->body->statements) {
stmts.Push(ctx.Clone(stmt));
}
const ast::BlockStatement* continuing = nullptr;
auto* body = b.Block(stmts);
auto* loop = b.Loop(body, continuing);
return loop;
});
ctx.Clone();
return Program(std::move(b));
}
} // namespace tint::transform