This makes it possible to use MakeIndexSequqnce in functions like:
template<typename T, size_t N>
constexpr auto foo(T (&a)[N])
This means AK/StdLibExtraDetails.h must now include AK/Types.h
for size_t, which means AK/Types.h can no longer include
AK/StdLibExtras.h (which arguably it shouldn't do anyways),
which requires rejiggering some things.
(IMHO Types.h shouldn't use AK::Details metaprogramming at all.
FlatPtr doesn't necessarily have to use Conditional<> and ssize_t could
maybe be in its own header or something. But since it's tangential to
this PR, going with the tried and true "lift things that cause the
cycle up to the top" approach.)
Remove all functions with platform #if's from fenv, and
add arch dependent implementations instead. The build
system now selects the implementation based on the platform.
For some reason I decided to change the argument passing order before
submitting my PR, but this would cause the oldset argument to always
be 0x74 as a0 is overridden with 0 in that order.
This is a minimal set of changes to allow `serenity.sh build riscv64` to
successfully generate the build environment and start building. This
includes some, but not all, assembly stubs that will be needed later on;
they are currently empty.
Doesn't use them in libc headers so that those don't have to pull in
AK/Platform.h.
AK_COMPILER_GCC is set _only_ for gcc, not for clang too. (__GNUC__ is
defined in clang builds as well.) Using AK_COMPILER_GCC simplifies
things some.
AK_COMPILER_CLANG isn't as much of a win, other than that it's
consistent with AK_COMPILER_GCC.
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.
These are aliases to `setjmp()` and `longjmp()` on our system,
as our implementations don't modify the signal mask.
This is required for the syzkaller executor process.
Calling sigprocmask() through the PLT requires setting the ebx register
to the address of the global offset table, otherwise chaos ensues. Also
the value of the ecx register was assumed to be preserved across that
function call despite the fact that it is caller-saved in the x86
calling convention.
The `-z,text` linker flag causes the linker to reject shared libraries
and PIE executables that have textrels. Our code mostly did not use
these except in one place in LibC, which is changed in this commit.
This makes GNU ld match LLD's behavior, which has this option enabled by
default.
TEXTRELs pose a security risk, as performing these relocations require
executable pages to be written to by the dynamic linker. This can
significantly weaken W^X hardening mitigations.
Note that after this change, TEXTRELs can still be used in ports, as the
dynamic loader code is not changed. There are also uses of it in the
kernel, removing which are outside the scope of this PR. To allow those,
`-z,notext` is added.
We have had these for quite a while, but we didn't compile them, and
used GCC's version instead. Clang does not come with these, so we have
to provide our own implementation.
Our implementation follows what `musl` and `FreeBSD` do, so this should
work fine, even if documentation can hardly be found for them.
SPDX License Identifiers are a more compact / standardized
way of representing file license information.
See: https://spdx.dev/resources/use/#identifiers
This was done with the `ambr` search and replace tool.
ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
