This moves all scheduler code into a separate file that is only compiled
when there's a scheduler in use (the tasks or asyncify scheduler, which
are both cooperative). The main goal of this change is to make it easier
to add a new "scheduler" based on OS threads.
It also fixes a few subtle issues with `-gc=none`:
- Gosched() panicked. This is now fixed to just return immediately
(the only logical thing to do when there's only one goroutine).
- Timers aren't supported without a scheduler, but the relevant code
was still present and would happily add a timer to the queue. It
just never ran. So now it exits with a runtime error, similar to any
blocking operation.
Volatile loads/stors are only useful for communication with interrupts
or for memory-mapped I/O. They do not provide any sort of safety for
sync.Mutex, while making it *appear* as if it is more safe.
* `sync.Mutex` cannot be used safely inside interrupts, because any
blocking calls (including `Lock`) will cause a runtime panic.
* For multithreading, `volatile` is also the wrong choice. Atomic
operations should be used instead, and the current code would not
work for multithreaded programs anyway.
TODO: Remove the go.mod/go.sum in internal/tools once doing so doesn't break CI (e.g. once we drop support for go 1.19)
* builder/cc1as.h: fix typo found by 'make spell'
* GNUmakefile: remove exception for inbetween, fix instance now found by 'make spell'
* GNUmakefile: remove exception for programmmer, fix instance now found by 'make spell'
* go.mod: use updated misspell. GNUmakefile: add spellfix target, use it.
* ignore directories properly when invoking spellchecker.
* make spell: give internal/tools its own go.mod, as misspell requires newer go
* make lint: depend on tools and run the installed revive
(which was perhaps implied by the change that added revive to internal/tools,
but not required in GNUmakefile until we gave internal/tools its own temporary go.mod)
* .github: now that 'make spell' works well, run it from CI
* GNUmakefile: make spell now aborts if it finds misspelt words, so what it finds doesn't get lost in CI logs
* GNUmakefile: tools: avoid -C option on go generate to make test-llvm15-go119 circleci job happy, see
https://cs.opensource.google/go/go/+/2af48cbb7d85e5fdc635e75b99f949010c607786
* internal/tools/go.mod: fix format of go version to leave out patchlevel, else go complains.
This bug can be triggered by the following series of events:
A acquires a write lock
B starts waiting for a read lock
C starts waiting for a read lock
A releases the write lock
After this, both B and C are supposed to be resumed as a read-lock is available.
However, with the previous implementation, only C would be resumed immediately.
Other goroutines could immediately acquire the read lock, but B would not be resumed until C released the read lock.
Ayke van Laethem
dkegel-fastly
hongkuang
soypat
deadprogram
Anuraag Agrawal
Tim Schaub
Nia Waldvogel
Federico G. Schwindt
Cornel
Jaden Weiss
Jaden Weiss