mirror of https://github.com/svaarala/duktape.git
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
74 lines
3.6 KiB
74 lines
3.6 KiB
=========================
|
|
Duktape 2.3 release notes
|
|
=========================
|
|
|
|
Release overview
|
|
================
|
|
|
|
Main changes in this release (see RELEASES.rst for full details):
|
|
|
|
* TBD.
|
|
|
|
* DUK_USE_ALIGN_BY now always defaults to 8 (natural alignment) to avoid any
|
|
potentially unsafe assumptions about compiler behavior for unaligned memory
|
|
accesses and pointers (which may be an issue even on x86).
|
|
|
|
* duk_xxx_literal() API call variants which take a plain C literal argument,
|
|
for example duk_get_prop_literal(ctx, -2, "myProperty"). The calls are
|
|
conceptually similar to the duk_xxx_string() variants, but can take advantage
|
|
of the fact that e.g. string length for a C literal can be determined at
|
|
compile time using sizeof("myProperty") - 1 (the -1 is for NUL termination).
|
|
Literal strings used by application code are also automatically pinned
|
|
between mark-and-sweep rounds, and a small lookup cache makes mapping a C
|
|
literal to a heap string object quite fast (almost as fast as using a heapptr).
|
|
For now the calls are experimental.
|
|
|
|
Upgrading from Duktape 2.2
|
|
==========================
|
|
|
|
No action (other than recompiling) should be needed for most users to upgrade
|
|
from Duktape v2.2.x. Note the following:
|
|
|
|
* TBD.
|
|
|
|
* If performance matters, you might consider using duk_xxx_literal() variants
|
|
in place of duk_xxx_string() variants when the argument is a C literal.
|
|
With literal pinning and the literal lookup cache this improves property
|
|
access performance around 20% with minimal application changes. Make sure
|
|
that the arguments are C literals, e.g. duk_get_prop_literal(ctx, "mykey")
|
|
and not pointers to strings like duk_get_prop_literal(ctx, strptr).
|
|
|
|
* If you're using the duk_xxx_heapptr() API call variants, you might consider
|
|
switching to the duk_xxx_literal() variants. They are less error prone, and
|
|
with literal pinning and the literal lookup cache almost as fast as using a
|
|
borrowed heap pointer.
|
|
|
|
* If you're working with a low memory target or any other target where memory
|
|
usage matters, you may want to ensure UDK_USE_LITCACHE_SIZE is undefined in
|
|
configure.py configuration (this is included in low_memory.yaml base config).
|
|
|
|
* If you're working with a low memory target or any other target where memory
|
|
usage matters, you may want to force DUK_USE_ALIGN_BY to a lower value
|
|
(4 or 1) to reduce memory overhead. For most targets the memory overhead
|
|
is not important.
|
|
|
|
* Base-64 and hex encoding/decoding support is now configurable and disabled
|
|
by default in the example low_memory.yaml configuration. Enable them
|
|
manually if necessary using DUK_USE_BASE64_SUPPORT and DUK_USE_HEX_SUPPORT.
|
|
|
|
* Several -fsanitize=undefined warnings have been fixed in the default
|
|
configuration using explicit checks to avoid undefined behavior. For
|
|
example, floating point division by zero is avoided and behavior in that
|
|
case is implemented explicitly, at some cost in footprint and performance.
|
|
For many compilers the undefined behavior assumptions in Duktape source
|
|
are fine, and you can remove the extra overhead by enabling the
|
|
DUK_USE_ALLOW_UNDEFINED_BEHAVIOR option in configure.py (this option is
|
|
enabled in the low_memory.yaml and performance_sensitive.yaml example
|
|
configurations). Note, however, that recent gcc/clang versions are
|
|
optimizing around undefined behavior so while relying on undefined behavior
|
|
may work in one version, it may break with newer compiler versions.
|
|
|
|
* The console extra (extras/console) now by default uses ``stdout`` for log
|
|
levels up to info, and ``stderr`` for warn and above. To restore previous
|
|
behavior (stdout only) use the ``DUK_CONSOLE_STDOUT_ONLY`` flag in
|
|
``duk_console_init()``.
|
|
|