tree 0e56d03d9656f6edb0f5226ddee0b732e42f6368
parent 57e864d0b4b51ff0b008383754511243973b7c1e
author Xing Xue <xingxue@outlook.com> 1707855084 -0500
committer Copybara-Service <copybara-worker@google.com> 1707855438 -0800

[OpenMP][AIX]Define struct kmp_base_tas_lock with the order of two members swapped for big-endian (#79188)

The direct lock data structure has bit `0` (the least significant bit)
of the first 32-bit word set to `1` to indicate it is a direct lock. On
the other hand, the first word (in 32-bit mode) or first two words (in
64-bit mode) of an indirect lock are the address of the entry allocated
from the indirect lock table. The runtime checks bit `0` of the first
32-bit word to tell if this is a direct or an indirect lock. This works
fine for 32-bit and 64-bit little-endian because its memory layout of a
64-bit address is (`low word`, `high word`). However, this causes
problems for big-endian where the memory layout of a 64-bit address is
(`high word`, `low word`). If an address of the indirect lock table
entry is something like `0x110035300`, i.e., (`0x1`, `0x10035300`), it
is treated as a direct lock. This patch defines `struct
kmp_base_tas_lock` with the ordering of the two 32-bit members flipped
for big-endian PPC64 so that when checking/setting tags in member
`poll`, the second word (the low word) is used. This patch also changes
places where `poll` is not already explicitly specified for
checking/setting tags.

GitOrigin-RevId: ac97562c99c3ae97f063048ccaf08ebdae60ac30