v8/test/mjsunit/es6/debug-evaluate-arrow-function-receiver.js
yangguo 089edbfa97 [debugger] fix debug-evaluate wrt shadowed context var.
Debug-evaluate used to resolve stack variables that shadow
context variables incorrectly, since the stack variable is
not visible in the context chain.

To fix this, we limit local variables accessible by debug-
evaluate to the ones directly referenced inside the function.
What is not referenced by the function itself, is considered
optimized out and not accessible by debug-evaluate.

To achieve this, we duplicate the entire context chain up to
the native context, and write back changes after debug-
evaluate. Changes to the original context chain will however
be overwritten. This already happens for catch and block
scopes though.

Also fix a crash caused by declaring variables inside debug-
evaluate.

R=mstarzinger@chromium.org
BUG=v8:4593
LOG=N

Review URL: https://codereview.chromium.org/1500933002

Cr-Commit-Position: refs/heads/master@{#32828}
2015-12-14 10:25:11 +00:00

117 lines
2.6 KiB
JavaScript

// Copyright 2015 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// Flags: --expose-debug-as debug
// Test that debug-evaluate can find the correct this value for an arrow
// function, if "this" is referenced within the arrow function scope.
Debug = debug.Debug
var break_count = 0;
var exception = null;
function listener(event, exec_state, event_data, data) {
if (event != Debug.DebugEvent.Break) return;
try {
for (var i = 0; i < exec_state.frameCount() - 1; i++) {
var frame = exec_state.frame(i);
var this_value = frame.evaluate("this").value();
var expected = frame.sourceLineText().match(/\/\/ (.*$)/)[1];
print(expected, this_value, frame.sourceLineText());
assertEquals(String(expected), String(this_value));
}
break_count++;
} catch (e) {
exception = e;
print(e + e.stack);
}
}
// Context-allocated receiver.
function f() {
debugger; // foo
return () => {
debugger; // foo
with ({}) {
return () => {
debugger; // foo
try {
throw new Error();
} catch (e) {
return () => {
(() => this); // bind this.
debugger; // foo
return () => {
debugger; // undefined
return g.call("goo"); // undefined
}
};
}
};
}
};
}
// Stack-allocated receiver.
function g() {
debugger; // goo
return () => {
debugger; // undefined
with ({}) {
return () => {
debugger; // undefined
try {
throw new Error();
} catch (e) {
return () => {
debugger; // undefined
return f.call("foo"); // undefined
};
}
};
}
};
}
Debug.setListener(listener);
var h = f.call("foo");
for (var i = 0; i < 20; i++) h = h();
var h = g.call("goo");
for (var i = 0; i < 20; i++) h = h();
function x() {
(() => this); // bind this.
function y() {
(() => {
(() => this); // bind this.
debugger; // Y
})(); // Y
}
y.call("Y"); // X
}
x.call("X");
function u() {
(() => this);
function v() {
(() => {
debugger; // undefined
})(); // V
}
v.call("V"); // U
}
u.call("U");
(() => {
(() => this);
debugger; // [object global]
})();
Debug.setListener(null);
assertEquals(55, break_count);
assertNull(exception);