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wasi-threads: fix use of wait in test (#5858)

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As @yamt points out [here], the `wait`/`notify` pairing used in this
manual WAT test was not effective. The `wait` always immediately
returned, meaning that the main thread essentially spins until a counter
is atomically incremented. This is fine for test correctness, but was
not the original intent, which was lost in a refactoring. This change
uses the `$i` local to keep track of the counter value we expect to see
for the `wait`, so that the `wait`/`notify` pair actually waits as
expected.

[here]: https://github.com/bytecodealliance/wasmtime/pull/5484#discussion_r1101200012
This commit is contained in:
Andrew Brown
2023-02-23 07:23:58 -08:00
committed by GitHub
parent 0521155896
commit f6b16a7178
1 changed files with 8 additions and 5 deletions
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13
tests/all/cli_tests/threads.wat
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@@ -21,12 +21,15 @@
(drop (call $__wasi_thread_spawn (i32.const 0)))
;; Wait for all the threads to notify us that they are done.
(local.set $i (i32.const 0))
(loop $again
;; Retrieve the i32 at address 128, compare it to -1 (it should always
;; fail) and load it atomically to check if all three threads are
;; complete. This wait is for 1ms or until notified, whichever is first.
(drop (memory.atomic.wait32 (i32.const 128) (i32.const -1) (i64.const 1000000)))
(br_if $again (i32.lt_s (i32.atomic.load (i32.const 128)) (i32.const 3)))
;; Wait for the i32 at address 128 to be incremented by each thread. We
;; maintain a local $i with the atomically loaded value as the expected
;; wait value and to check if all three threads are complete. This wait is
;; for 1ms or until notified, whichever is first.
(drop (memory.atomic.wait32 (i32.const 128) (local.get $i) (i64.const 1000000)))
(local.set $i (i32.atomic.load (i32.const 128)))
(br_if $again (i32.lt_s (local.get $i) (i32.const 3)))
)
;; Print "Done".