The __builtin_bswapXX from GCC and Clang are preferred when
they are available. This can allow compilers to emit the x86 MOVBE
instruction instead of doing a load + byteswap as two instructions
(which would happen if the byteswapping is done in inline asm).
bswap16, bswap32, and bswap64 exist in system headers on *BSDs
and Darwin. #defining bswap16 on NetBSD results in a warning about
macro redefinition. It's safest to avoid this namespace conflict
completely.
No OS supported by tuklib_integer.h uses byteswapXX names and
a web search doesn't immediately find any obvious danger of
namespace conflicts. So let's try these still-pretty-short names
for the macros.
Thanks to Sam James for pointing out the compiler warning on
NetBSD 10.0.
The API docs clearly say that if error_pos isn't NULL then *error
is always set on any error. However, it wasn't touched if str == NULL
or filters == NULL or unsupported flags were specified.
Fixes: cedeeca2ea
It is logical why it cannot know for sure that the value has
to be at most 4 if it is less than 16.
The x86 filter is based on a very old LZMA SDK version. Newer
ones have quite a different implementation for the same filter.
Thanks to Sam James.
On macOS, we get:
```
signals.c: In function 'signals_init':
signals.c:76:17: error: conversion to 'sigset_t' {aka 'unsigned int'} from 'int' may change the sign of the result [-Werror=sign-conversion]
76 | sigaddset(&hooked_signals, sigs[i]);
| ^~~~~~~~~
signals.c:81:17: error: conversion to 'sigset_t' {aka 'unsigned int'} from 'int' may change the sign of the result [-Werror=sign-conversion]
81 | sigaddset(&hooked_signals, message_progress_sigs[i]);
| ^~~~~~~~~
signals.c:86:9: error: conversion to 'sigset_t' {aka 'unsigned int'} from 'int' may change the sign of the result [-Werror=sign-conversion]
86 | sigaddset(&hooked_signals, SIGTSTP);
| ^~~~~~~~~
```
We use `int` for `hooked_signals` but we can't just cast to whatever
`sigset_t` is because `sigset_t` is an opaque type. It's an unsigned int
on macOS. On macOS, `sigaddset` is implemented as a macro.
Just suppress -Wsign-conversion for `signals_init` for macOS given
there's no real nice way of fixing this.
A few lines were reordered, a few ARRAY_SIZE were changed to sizeof,
and a few uint32_t were changed to size_t. No real functional changes
were intended.
We need this for when we're passing sanitizer flags or -gdwarf-4 for Clang
with Valgrind. Just always start with -O2 if CFLAGS isn't set in the
environment and append what was passed on the command line.
Using `--trace-children=yes` has a trade-off here, as it makes
`test_scripts.sh` pretty slow when calling various non-xz utilities.
But I also feel like it's not useless to have Valgrind used there and it's
not easy to exclude Valgrind just for that one test...
I did consider using AX_VALGRIND_CHECK [0][1] but I couldn't get it working
immediately with some conditionally-built tests and I wondered if it was
worth spending time on at least while we're debating xz's future build
system situation.
[0] https://www.gnu.org/software/autoconf-archive/ax_valgrind_check.html
[1] https://tecnocode.co.uk/2014/12/23/automatically-valgrinding-code-with-ax_valgrind_check/
This is *NOT* done for security reasons even though the backdoor
relied on the ifunc code. Instead, the reason is that in this
project ifunc provides little benefits but it's quite a bit of
extra code to support it. The only case where ifunc *might* matter
for performance is if the CRC functions are used directly by an
application. In normal compression use it's completely irrelevant.
Lasse Collin
Sam James
Ryan Carsten Schmidt