The -*- file variable lines -*- establish per-file settings that Emacs will
pick up. This patch makes the following changes to those lines (and touches
nothing else):
- Never set the buffer's mode.
Years ago, Emacs did not have a good JavaScript mode, so it made sense
to use Java or C++ mode in .js files. However, Emacs has had js-mode for
years now; it's perfectly serviceable, and is available and enabled by
default in all major Emacs packagings.
Selecting a mode in the -*- file variable line -*- is almost always the
wrong thing to do anyway. It overrides Emacs's default choice, which is
(now) reasonable; and even worse, it overrides settings the user might
have made in their '.emacs' file for that file extension. It's only
useful when there's something specific about that particular file that
makes a particular mode appropriate.
- Correctly propagate settings that establish the correct indentation
level for this file: c-basic-offset and js2-basic-offset should be
js-indent-level. Whatever value they're given should be preserved;
different parts of our tree use different indentation styles.
- We don't use tabs in Mozilla JS code. Always set indent-tabs-mode: nil.
Remove tab-width: settings, at least in files that don't contain tab
characters.
- Remove js2-mode settings that belong in the user's .emacs file, like
js2-skip-preprocessor-directives.
This is unnecessary now that object jsids no longer exist. Both string and
symbol jsids point only to GC things in the atoms compartment, which are safe
to pass to any compartment without wrapping.
--HG--
extra : rebase_source : 82c21e8474df05b1bb42c14d872c981205bbe879
Layout: js/src/vm/Symbol.h defines the new class JS::Symbol. JS::Symbol is the
same size as JSString on all platforms, because the allocator does not support
smaller allocations.
Allocation: Since the purpose of symbols is to serve as property keys, they are
always allocated in the atoms compartment.
We take a lock when allocating. This could probably be replaced with a
main-thread-only assertion. However, if atom allocation is not already a
bottleneck, symbol allocation probably never will be.
Symbols are given their own finalize-class in the GC. This means we allocate a
page per zone for symbols, even though they are only ever allocated in the
atoms zone. Terrence thought this could be easily fixed later. It should be; we
never touch the page, but a 32-bit virtual address space does not just have
infinite pages to spare.
A jsapi-test exercises the new symbol allocation code. A few oddities in
jsapi-tests are fixed in passing.
Discussion after review led to some new assertions about minimum object size in
AllocateObject and AllocateNonObject.
--HG--
extra : rebase_source : 45abb651d3b1b493d77a5dd0eb554f96b058c63a
