1525331 - ParseNode::pn_type should be const

Status: RESOLVED FIXED

(Core :: JavaScript Engine, enhancement)

Description

[Ashley Hauck [:khyperia]]

We shouldn't be doing in-place mutations of parsenodes. It's spooky and bad and prevents a lot of improvements to code.

Next steps after making pn_type const is to remove the ParseNode union and rather store fields on the ParseNode classes themselves. We then would be able to have variable-sized allocations, which will likely at least offset any losses introduced in this patch due to allocating more in the constant folder.

Comment 1

[Ashley Hauck [:khyperia]]

Attachment: bug 1525331 - Make ParseNode::pn_type const.

Comment 2

[Ashley Hauck [:khyperia]]

Attachment: bug 1525331 - Move fields from union to individual subclasses.

Comment 3

[Ashley Hauck [:khyperia]]

Tacked on the Next steps described in the first comment, just to keep things rolling. Feel free to review only the first patch and I can pull the second patch into its own bug.

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/aba804ffb8e8
Make ParseNode::pn_type const. r=jorendorff
https://hg.mozilla.org/integration/autoland/rev/a226aae4349f
Move fields from union to individual subclasses. r=jorendorff

Comment 5

[Raul Gurzau (:RaulG)]

https://hg.mozilla.org/mozilla-central/rev/aba804ffb8e8
https://hg.mozilla.org/mozilla-central/rev/a226aae4349f