This rewrite simplifies the channel implementation considerably, with
34% less LOC. Perhaps the most important change is the removal of the
channel state, which made sense when we had only send and receive
operations but only makes things more compliated when multiple select
operations can be pending on a single channel.
I did this rewrite originally to make it possible to make channels
parallelism-safe. The current implementation is not parallelism-safe,
but it will be easy to make it so (the main additions will be a channel
lock, a global select lock, and an atomic compare-and-swap in
chanQueue.pop).
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.
Making this work on all targets was interesting but there's now a test
in place to make sure this works on all targets that have the CGo test
enabled (which is almost all targets).
This fixes a bug where output would not actually be written to stdout
before exiting the process, leading to a flaky Windows CI. Exiting using
`exit(0)` appears to fix this.
For some background, see: https://github.com/tinygo-org/tinygo/pull/4589
* Move environment functions to their own files.
* Rewrite the WASIp2 version of environment variables to be much
simpler (don't go through C functions).
Use a single package for certain constants that must be the same between
the compiler and the runtime.
While just using the same values in both places works, this is much more
obvious and harder to mess up. It also avoids the need for comments
pointing to the other location the constant is defined. And having it in
code makes it possible for IDEs to analyze the source.
In the future, more such constants and maybe algorithms can be added.
This is similar to https://github.com/tinygo-org/tinygo/pull/3899, but
smaller and hopefully just as efficient.
Thanks to @HattoriHanzo031 for starting this work, benchmarking, and for
improving the performance of the code even further.
* internal/wasm-tools, internal/cm: update wasm-tools-go to v0.3.1 and regenerate bindings
* syscall: use new (cm.Result).Result() method instead of OK() and Err()
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.
Every time we overflow the stack, we have to do a full rescan of the heap. Making this larger
means fewer overflows and thus fewer secondary+ heap scans.
With a few small modifications, all the problems with `-gc=precise` in
WebAssembly seem to have been fixed.
I didn't do any performance measurements, but this is supposed to
improve GC performance.
This often doesn't work because there might not be a current task to
push the defer frame to. It will instead show an unhelpful nil pointer
dereference panic.
We could make this work with a separate defer stack for interrupts (as
if they were newly started goroutines) but that is difficult with
multiple interrupts happening at the same time (we shouldn't jump to a
previous interrupt in `panic()`!). So instead, disable defer altogether
in interrupts and adjust panic/recover accordingly.
This adds support for //go:wasmexport with `-target=wasm` (in the
browser). This follows the //go:wasmexport proposal, meaning that
blocking functions are not allowed.
Both `-buildmode=default` and `-buildmode=c-shared` are supported. The
latter allows calling exported functions after `go.run()` has returned.
This adds support for the `//go:wasmexport` pragma as proposed here:
https://github.com/golang/go/issues/65199
It is currently implemented only for wasip1 and wasm-unknown, but it is
certainly possible to extend it to other targets like GOOS=js and
wasip2.
Ayke van Laethem
leongross
Ben Krieger
Randy Reddig
Joonas Bergius
Damian Gryski
sago35
Elias Naur
BCG