0896586083
Goal of this CL: explicit return from non-async function has position after return expression as return position (will unblock [1]). BytecodeArrayBuilder has SetStatementPosition and SetExpressionPosition methods. If one of these methods is called then next generated bytecode will get passed position. It's general treatment for most cases. Unfortunately it doesn't work for Returns: - debugger requires source positions exactly on kReturn bytecode in stepping implementation, - BytecodeGenerator::BuildReturn and BytecodeGenerator::BuildAsyncReturn generates more then one bytecode and general solution will put return position on first generated bytecode, - it's not easy to split BuildReturn function into two parts to allow something like following in BytecodeGenerator::VisitReturnStatement since generated bytecodes are actually controlled by execution_control(). ..->BuildReturnPrologue(); ..->SetReturnPosition(stmt); ..->Return(); In this CL we pass ReturnStatement through ExecutionControl and use it for position when we emit return bytecode right here. So this CL only will improve return position for returns inside of non-async functions, I'll address async functions later. [1] https://chromium-review.googlesource.com/c/543161/ Change-Id: Iede512c120b00c209990bf50c20e7d23dc0d65db Reviewed-on: https://chromium-review.googlesource.com/560738 Commit-Queue: Aleksey Kozyatinskiy <kozyatinskiy@chromium.org> Reviewed-by: Adam Klein <adamk@chromium.org> Reviewed-by: Michael Starzinger <mstarzinger@chromium.org> Reviewed-by: Ross McIlroy <rmcilroy@chromium.org> Reviewed-by: Jakob Gruber <jgruber@chromium.org> Cr-Commit-Position: refs/heads/master@{#46687}
37 lines
926 B
JavaScript
37 lines
926 B
JavaScript
// Copyright 2017 the V8 project authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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const Debug = debug.Debug;
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let exception = null;
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let step_count = 0;
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Debug.setListener((event, execState, eventData, data) => {
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if (event != Debug.DebugEvent.Break) return;
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try {
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const line = execState.frame(0).sourceLineText();
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print(line);
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const [match, expected_count, step] = /\/\/ B(\d) (\w+)$/.exec(line);
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assertEquals(step_count++, parseInt(expected_count));
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if (step != "Continue") execState.prepareStep(Debug.StepAction[step]);
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} catch (e) {
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print(e, e.stack);
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exception = e;
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}
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});
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function f(x) {
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debugger; // B0 StepNext
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with ({}) { // B1 StepNext
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return x // B2 StepNext
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; // B3 Continue
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}
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}
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f(42);
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assertNull(exception);
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assertEquals(4, step_count);
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