* Rely on libSystem when targeting macOS.
* Make tools/gen_outline_atomics.zig more idiomatic.
* Remove the CPU detection / auxval checking from compiler_rt. This
functionality belongs in a different component. Zig's compiler_rt
must not rely on constructors. Instead it will export a symbol for
setting the value, and start code can detect and activate it.
* Remove the separate logic for inline assembly when the target does or
does not have lse support. `.inst` works in both cases.
POLYVAL is GHASH's little brother, required by the AES-GCM-SIV
construction. It's defined in RFC8452.
The irreducible polynomial is a mirror of GHASH's (which doesn't
change anything in our implementation that didn't reverse the raw
bits to start with).
But most importantly, POLYVAL encodes byte strings as little-endian
instead of big-endian, which makes it a little bit faster on the
vast majority of modern CPUs.
So, both share the same code, just with comptime magic to use the
correct endianness and only double the key for GHASH.
Closes#7484. Right now for UEFI targets an alignment
of 32 is being used for no reason other than support
a rare bytecode. As this is far from the standard case,
removing this alignment and using the default one,
as most toolchains do, should be the desired behavior.
I wasn't able to create a reduced test case for this but the reasoning
can be seen in `abiAlignmentAdvancedUnion` where if `strat` was lazy
`hasRuntimeBitsAdvanced` would be given `null` instead of `sema`
which would cause eager evaluation when it is not valid or desired.
There was no check for linker errors after flushing,
which meant that if the link failed the build would
continue and try to copy the non-existant exe, and
also write the manifest as if it had succeeded.
Also adds parsing of lld output, which is surfaced at the
end of the compilation with the other errors instead
of via stderr
While it is already mentioned on the `items` attributes of the structs, it is
interesting to comment in every method potentially invalidating pointers to items
that they may do so.
* std.crypto.onetimeauth.ghash: faster GHASH on modern CPUs
Carryless multiplication was slow on older Intel CPUs, justifying
the need for using Karatsuba multiplication.
This is not the case any more; using 4 multiplications to multiply
two 128-bit numbers is actually faster than 3 multiplications +
shifts and additions.
This is also true on aarch64.
Keep using Karatsuba only when targeting x86 (granted, this is a bit
of a brutal shortcut, we should really list all the CPU models that
had a slow clmul instruction).
Also remove useless agg_2 treshold and restore the ability to
precompute only H and H^2 in ReleaseSmall.
Finally, avoid using u256. Using 128-bit registers is actually faster.
* Use a switch, add some comments
The packed struct example was mistakenly applying endianness where it
shouldn't have been. This wasn't being caught because we don't currently
test the examples on Big-endian systems.
I updated the test to remove the endianness where it didn't apply, and
added a new part of the test to demonstrate when it would apply.
perf_event_attr.type needs to take a runtime defined value to enable
dynamic PMU:s, such as kprobe and uprobe. This value can exceed
predefined values defined in the linux headers.
reference: perf_event_open(2) man page
