This option sets -fprofile-instr-generate -fcoverage-mapping for Clang
builds only on almost all of Userland. Loader and LibTimeZone are
exempt. This can be used for generating code coverage reports, or even
PGO in the future.
This commit addresses the following shortcomings of our current, simple
and elegant memset function:
- REP STOSB/STOSQ has considerable startup overhead, it's impractical to
use for smaller sizes.
- Up until very recently, AMD CPUs didn't have support for "Enhanced REP
MOVSB/STOSB", so it performed pretty poorly on them.
With this commit applied, I could measure a ~5% decrease in `test-js`'s
runtime when I used qemu's TCG backend. The implementation is based on
the following article from Microsoft:
https://msrc-blog.microsoft.com/2021/01/11/building-faster-amd64-memset-routines
Two versions of the routine are implemented: one that uses the ERMS
extension mentioned above, and one that performs plain SSE stores. The
version appropriate for the CPU is selected at load time using an IFUNC.
IFUNC is a GNU extension to the ELF standard that allows a function to
have multiple implementations. A resolver function has to be called at
load time to choose the right one to use. The PLT will contain the entry
to the resolved function, so branching and more indirect jumps can be
avoided at run-time.
This mechanism is usually used when a routine can be made faster using
CPU features that are available in only some models, and a fallback
implementation has to exist for others.
We will use this feature to have two separate memset implementations for
CPUs with and without ERMS (Enhanced REP MOVSB/STOSB) support.
Similarly to x86_64, Aarch64 is LP64, so its `uint64_t` type is
`unsigned long`.
Fixes a bunch of compiler warnings when compiling the LLVM runtime
libraries for the aarch64-pc-serenity target.
POSIX says that localtime should fail with EOVERFLOW if the result
cannot be represented, which is the case for most large (in absolute
value) time_t inputs, since they overflow (or underflow) tm_year, which
is an int. This patch introduces this functionality. Previously, tm_year
just overflowed (or underflowed) silently.
Incidentally, this partially fixes#12729 without solving the root
problem, which is that time_to_tm is linear in its input to determine
the number of years since epoch.
This means that the bash port mktime test no longer times-out in 60s,
but it still fails (faster) in some other place. Due to underlying issue
in the algorithm, the worst case inputs still take a couple of seconds
on my machine.
POSIX describes WCHAR_MIN and WCHAR_MAX in stdint.h(0P), while
wchar.h(0P) only says "as described in stdint.h".
As there isn't a trivial path of "may make visible", just move it to a
shared header and include it from both files.
On x86-64, `int64_t` is defined to be `long` (not `long long`) , so for
printing, the "l" format specifier has to be used instead of i686's
"ll".
A couple of these macros weren't updated when the x86-64 target was
added, so using them produced warnings like this:
> warning: format specifies type 'long long' but the argument has type
> 'int64_t' (aka 'long') [-Wformat]
>
> "DW_CFA_GNU_negative_offset_extended(%" PRId64 ")\n", offset);
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~
This commit changes the macros to be correct for both architectures, and
reorders them to be consistent and adds a couple missing ones for the
sake of completeness.
If we break out of the loop before we attempt to allocate again,
then we double free the memory pointed to by `name_path`.
Found by Static Analysis: Sonar Cloud
Instead, to determine these values (both the pts name and tty name), use
other methods. For determining the new name of the allocated psuedo
terminal, use ioctl on a file descriptor we got after opening /dev/ptmx
with the TIOCGPTN option.
For determining the name of TTY, we enumerate both /dev/pts and /dev
directories to find matching inode number and matching device mode.
This ioctl operation will allow userspace to determine the index number
of a MasterPTY after opening /dev/ptmx and actually getting an internal
file descriptor of MasterPTY.
Day and month name constants are defined in numerous places. This
pulls them together into a single place and eliminates the
duplication. It also ensures they are `constexpr`.
Ports / other userland often needs such an implementation to function.
Lets expose `AK::timing_safe_compare` under the same name used used in
OpenBSD / FreeBSD / Solaris and other projects.
This causes problems in code of the form
if (/* condition */)
FD_ZERO(&thing);
else
do_other_thing();
Wrapping the call to memset() in a do/while block fixes the issue.
I also added a common interface with StringView compatible parameters:
int serenity_setenv(const char*, ssize_t, const char*, ssize_t, int)
This function is called by both C and C++ API for setenv().
