This CL refines https://crrev.com/c/3829539 to only apply to let and
const declared variables. `var`s should stay `undefined`.
R=jarin@chromium.org
Bug: chromium:1328681
Change-Id: I35778c89fb04439348a4f6aebcdeb2db6234f9d0
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3848960
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Commit-Queue: Simon Zünd <szuend@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82640}
Consider the function:
function foo() {
debugger;
let y = 1;
}
V8 will elide the hole initialization for 'y'. When we pause at the
debugger statement, then 'y' evaluates to 'undefined'.
This CL fixes this in the ScopeIterator. When we encounter local
variables with an `undefined` value we check the static scope
information if we are stopped *before* the variable's initializer.
If yes, then we are in the variable's TDZ and report
"value unavailable".
Drive-by: Mark `GetSourcePosition()` as `const` to make it available
in the visitor method.
R=bmeurer@chromium.org
Bug: chromium:1328681
Change-Id: I8b966eaa2af64a35a58095a744440851760921a0
Fixed: chromium:1303493
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3829539
Commit-Queue: Simon Zünd <szuend@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82483}
This adds a new --experimental-value-unavailable flag, which is disabled
for now. When enabled the debugger reports values that are optimized out
by TurboFan and values of certain variables in Temporal Dead Zones (TDZ)
as unavailable. Internally we use a special `value_unavailable` accessor
info to represent these values, and on the debugger boundary we report
these properties with `value`, `get`, or `set`.
Doc: https://goo.gle/devtools-value-unavailable
Bug: chromium:1328681
Demo: devtools-dbg-stories.netlify.app/crbug-1328681-value-unavailable
Change-Id: Idb09a4a148335a950deae60f7c07caecc48826ba
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3627510
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/main@{#81509}
