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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/fuzzers/tint_ast_fuzzer/jump_tracker.h"
#include <cassert>
#include <unordered_set>
#include "src/tint/lang/wgsl/ast/break_statement.h"
#include "src/tint/lang/wgsl/ast/discard_statement.h"
#include "src/tint/lang/wgsl/ast/for_loop_statement.h"
#include "src/tint/lang/wgsl/ast/loop_statement.h"
#include "src/tint/lang/wgsl/ast/return_statement.h"
#include "src/tint/lang/wgsl/ast/switch_statement.h"
#include "src/tint/lang/wgsl/ast/while_statement.h"
#include "src/tint/lang/wgsl/sem/statement.h"
namespace tint::fuzzers::ast_fuzzer {
JumpTracker::JumpTracker(const Program& program) {
// Consider every AST node, looking for break and return statements.
for (auto* node : program.ASTNodes().Objects()) {
auto* stmt = node->As<ast::Statement>();
if (stmt == nullptr) {
continue;
}
if (stmt->As<ast::BreakStatement>()) {
// This break statement either exits a loop or a switch statement.
// Walk up the AST until either a loop or switch statement is found. In the former case,
// it is the innermost loop containing the break statement, and thus all the nodes
// encountered along the way are nodes that contain a break from the innermost loop.
// This records the statements encountered when walking up the AST from the break
// statement to the innermost enclosing loop or switch statement.
std::unordered_set<const ast::Statement*> candidate_statements;
for (const ast::Statement* current = stmt;;
current =
As<sem::Statement>(program.Sem().Get(current))->Parent()->Declaration()) {
if (current->Is<ast::ForLoopStatement>() || current->Is<ast::LoopStatement>() ||
current->Is<ast::WhileStatement>()) {
// A loop has been encountered, thus all that statements recorded until this
// point contain a break from their innermost loop.
for (auto* candidate : candidate_statements) {
contains_break_for_innermost_loop_.insert(candidate);
}
break;
}
if (current->Is<ast::SwitchStatement>()) {
// A switch statement has been encountered, so the break does not correspond to
// a loop break.
break;
}
candidate_statements.insert(current);
}
} else if (stmt->As<ast::ReturnStatement>()) {
// Walk up the AST from the return statement, recording that every node encountered
// along the way contains a return.
const ast::Statement* current = stmt;
while (true) {
contains_return_.insert(current);
auto* parent = program.Sem().Get(current)->Parent();
if (parent == nullptr) {
break;
}
current = parent->Declaration();
}
}
}
}
} // namespace tint::fuzzers::ast_fuzzer