According to [1] sections 7.4, 8.1, and 8.2, desktop and server
processors support fast unaligned access, but embedded systems likely
don't.
It's important that TUKLIB_FAST_UNALIGNED_ACCESS isn't defined when
-mstrict-align is in use because it will result in slower binaries
even if running on a processor that supports fast unaligned access.
It's because compilers will translate multibyte memcpy() to multiple
byte-by-byte instructions instead of wider loads and stores. The
compression times from [2] show this well:
Unaligned access CFLAGS Compression time
enabled -O2 -mno-strict-align 66.1 s
disabled -O2 -mno-strict-align 79.5 s
disabled -O2 -mstrict-align 79.9 s
enabled -O2 -mstrict-align 129.1 s
There currently (GCC 15.2) is no preprocessor macro on LoongArch
to detect if -mstrict-align or -mno-strict-align is in effect (the
default is -mno-strict-align). Use heuristics to detect which of the
flags is in effect.
[1] https://github.com/loongson/la-softdev-convention/blob/v0.2/la-softdev-convention.adoc
[2] https://github.com/tukaani-project/xz/pull/186#issuecomment-3494570304
Thanks-to: Li Chenggang <lichenggang@deepin.org>
Thanks-to: Xi Ruoyao
See: https://github.com/tukaani-project/xz/pull/186
lzma_lzma_decoder_memusage() returns UINT64_MAX if lc/lp/pb aren't
valid. alone_decoder.c and lzip_decoder.c didn't check the return
value because in both it is known that lc/lp/pb are valid. Make them
call the _nocheck() variant instead which skips the validation (it
already existed for LZMA2's internal use).
Fixes: Coverity CID 464658
Fixes: Coverity CID 897069
The partial_update_mode enumeration had three states, _DISABLED,
_START, and _ENABLED. Main thread changed it from _DISABLED to _START
while holding a mutex. Once set to _START, worker thread changed it
to _ENABLED without a mutex. Later main thread read it without a mutex,
so it could see either _START or _ENABLED. However, it made no
difference because the main thread checked for != _DISABLED, so
it didn't matter if it saw _START or _ENABLED.
Nevertheless, such things must not be done. It's clear it was a mistake
because there were two comments that directly contradicted each
other about how the variable was accessed.
Split the enumeration into two booleans:
- partial_update_enabled: A worker thread locks the mutex to read
this variable and the main thread locks the mutex to change the
value. Because only the main thread modifies the variable, the
main thread can read the value without locking the mutex.
This variable replaces the _DISABLED -> _START transition.
- partial_update_started is for worker thread's internal use and thus
needs no mutex. This replaces the _START -> _ENABLED transition.
Fixes: Coverity CID 456025
Fixes: bd93b776c1bd ("liblzma: Fix a deadlock in threaded decoder.")
In short, sort the names with this command (-k1,1 isn't needed because
the lines with names start with " -"):
LC_ALL=en_US.UTF-8 sort -k2,2 -k3,3 -k4,4 -k5,5
When THANKS was created, I wrote the names as "First Last" and attempted
to keep them sorted by last name / surname / family name. This works
with many names in THANKS, but it becomes complicated with names that
don't fit that pattern. For example, names that are written as
"Last First" can be manually sorted by family name, but only if one
knows which part of the name is the family name.[*] And of course,
the concept of first/last name doesn't apply to all names.
[*] xz had a co-maintainer who could help me with such names,
but fortunately he isn't working on the project anymore.
Adding the names in chronological order could have worked too, although
if something is contributed by multiple people, one would still have to
decide how to sort the names within the batch. Another downside would
be that if THANKS is updated in more than one work-in-progress branch,
merge conflicts would occur more often.
Don't attempt to sort by last name. Let's be happy that people tend to
provide names that can be expressed in a reasonable number of printable
Unicode characters. In practice, people have been even nicer: if the
native language doesn't use a Latin script alphabet, people often provide
a transliterated name (only or in addition to the original spelling),
which is very much appreciated by those who don't know the native script.
Treat the names as opaque strings or space-separated strings for sorting
purposes. This means that most names will now be sorted by first name.
There still are many choices how to sort:
(1) LC_ALL=en_US.UTF-8 sort
The project is in English, so this may sound like a logical choice.
However, spaces have a lower weight than letters, which results in
this order:
- A Ba
- Ab C
- A Bc
- A Bd
(2) LC_ALL=en_US.UTF-8 sort -k2,2
This first sorts by the first word and then by the rest of the
string. It's -k2,2 instead of -k1,1 to skip the leading dash.
- A Ba
- A Bc
- A Bd
- Ab C
I like this more than (1). One could add -k3,3 -k4,4 -k5,5 ... too.
With current THANKS it makes no difference but it might some day.
NOTE: The ordering in en_US.UTF-8 can differ between libc versions
and operating systems. Luckily it's not a big deal in THANKS.
(3) LC_ALL=en_US.UTF-8 sort -f -k2,2
Passing -f (--ignore-case) to sort affects sorting of single-byte
characters but not multibyte characters (GNU coreutils 9.9):
No -f With -f LC_ALL=C
Aa A.A A.A
A.A Aa Aa
Ää Ää Ä.Ä
Ä.Ä Ä.Ä Ää
In GNU coreutils, the THANKS file is sorted using "sort -f -k1,1".
There is also a basic check that the en_US.UTF-8 locale is
behaving as expected.
(4) LC_ALL=C sort
This sorts by byte order which in UTF-8 is the same as Unicode
code point order. With the strings in (1) and (2), this produces
the same result as in (2). The difference in (3) can be seen above.
The results differ from en_US.UTF-8 when a name component starts
with a lower case ASCII letter (like "von" or "de"). Worse, any
non-ASCII characters sort after ASCII chars. These properties might
look weird in English language text, although it's good to remember
that en_US.UTF-8 sorting can appear weird too if one's native
language isn't English.
The choice between (2) and (4) was difficult but I went with (2).
;-)
To make a non-threaded liblzma-only build work with WASI SDK, <signal.h>
and mythread_sigmask() were omitted from mythread.h in the commit
81db3b889830. This broke non-threaded full build with Emscripten because
src/xz/signals.c needs mythread_sigmask() (liblzma-only build was fine).
If __wasm__ is defined, omit <signal.h> and mythread_sigmask() in
non-threaded builds only when __EMSCRIPTEN__ isn't defined.
Reported-by: Marcus Tillmanns
Thanks-to: ChanTsune
Fixes: https://github.com/tukaani-project/xz/issues/161
Fixes: 81db3b889830 ("mythread.h: Disable signal functions in builds targeting Wasm + WASI.")
getauxval() can be available even if HWCAP_CRC32 isn't #defined, so
both have to be checked. HWCAP_CRC32 was added in glibc 2.24 (2016).
Fixes: https://github.com/tukaani-project/xz/issues/190
When no memory usage limits have been set by the user, the default
for multithreaded mode has been 1/4 of total RAM. If this limit is
too high and memory allocation fails, liblzma (and xz) fail. Perhaps
liblzma should handle it better by reducing the number of threads
and continuing with the amount of memory it can allocate, but currently
that isn't the case.
If resource limits were set to about 1/4 of RAM or lower, then xz
could fail for the above reason. This commit makes xz look at
RLIMIT_DATA, RLIMIT_AS, and RLIMIT_VMEM when they are available,
and set the limit 64 MiB below the lowest of those limits. This is
more or less a hack just like the 1/4-of-RAM method is, but this is
simple and quick to implement.
On Linux, there are other limits like cgroup v2 memory.max which
can still make xz fail. The same is likely possible with FreeBSD's
rctl(8).
Co-authored-by: Lasse Collin <lasse.collin@tukaani.org>
Thanks-to: Fangrui Song
Fixes: https://github.com/tukaani-project/xz/issues/195
Closes: https://github.com/tukaani-project/xz/pull/196
GitHub has removed the runner image.
A breakage with CLMUL CRC code occurred with VS 2019 but not 2022,
see b5a5d9e3f702. MS supports VS 2019 for a few more years, so it's
unfortunate that it can no longer be tested on GitHub.
It feels better to fix the docs than change the code because this
way newly-written applications will be forced to be compatible with
the lzma_allocator behavior of old liblzma versions. It can matter
if someone builds the application against an older liblzma version.
Fixes: https://github.com/tukaani-project/xz/issues/183
Set also shell because the xz*.in files start with '#!@POSIX_SHELL@'.
SC1003 and SC2016 are only info messages, not warnings. Several other
shellcheck info messages remain. They are safe to ignore, but I didn't
want to disable them now.
Partially-fixes: https://github.com/tukaani-project/xz/issues/174
Sometimes the VM workflows (like FreeBSD VM on Ubuntu) get stuck
and the default timeout is six hours. While at it, set a sensible
timeout for all workflows.
