Found this bug while trying to use the upstream testing package instead
of our own. The io/fs package wasn't passing, because the test was run
in a separate goroutine (and therefore a separate thread, with its own
stack) instead of all in the same thread with our own stack
creation/switching implementation.
This makes sure system calls like read don't return EINTR but instead
restart the call on an interrupt. This is by far the more sensible
option, the default POSIX behavior of returning EINTR is extremely
error-prone.
Found this bug while trying to use the upstream testing package instead
of our own.
This commit adds support for a scheduler that runs a scheduler on all
available cores. It is meant to be used on baremetal systems with a
fixed number of cores, such as the RP2040.
The initial implementation adds support for multicore scheduling to the
riscv-qemu target as a convenient testing target. This means that this
new multicore scheduler is tested in CI, including a bunch of standard
library tests (`make tinygo-test-baremetal`). This should ensure the new
scheduler is reasonably well tested before trying to use it on
harder-to-debug targets like the RP2040.
The system stack is only needed when we're not on it. So we can directly
call task.SystemStack() without problems.
This also saves a tiny bit of binary size.
For the threads scheduler, it makes sense to have NumCPU available.
For all other schedulers, the number of available CPUs is practically
limited to one by the scheduler (even though the system might have more
CPUs).
This is more descriptive: the call is to exit a task, not to pause it.
This also makes it more obvious that there's an optimization
opportunity: to free the stack explicitly after the goroutine returns
(or to keep it as a cache for the next stack allocation).
This is not a scheduler in the runtime, instead every goroutine is
mapped to a single OS thread - meaning 1:1 scheduling.
While this may not perform well (or at all) for large numbers of
threads, it greatly simplifies many things in the runtime. For example,
blocking syscalls can be called directly instead of having to use epoll
or similar. Also, we don't need to do anything special to call C code -
the default stack is all we need.
This directive caused the code to be put in a non-executable area on
Windows which caused a segmentation fault. This patch fixes the issue by
removing `.section` directives, fixing windows/arm64 support.
The mutex implementation needs a different implementation once support
for threading lands. This implementation just moves code to the
internal/task package to centralize these algorithms.
See the code comments for details. But in short, this implements a futex
for the cooperative scheduler (that is single threaded and
non-reentrant). Similar implementations can be made for basically every
other operating system, and even WebAssembly with the threading
(actually: atomics) proposal.
Using this basic futex implementation means we can use the same
implementation for synchronisation primitives on cooperative and
multicore systems.
For more information on futex across operating systems:
https://outerproduct.net/futex-dictionary.html
This adds some non-atomic types that have the same interface as the ones
in sync/atomic.
We currently don't need these to be atomic (because the scheduler is
entirely cooperative), but once we add support for a scheduler with
multiple threads and/or preemptive scheduling we can trivially add some
type aliases under a different build tag in the future when real
atomicity is needed for threading.
Previously the assembler was reordering this code:
jal tinygo_scanstack
move $a0, $sp
Into this:
jal tinygo_scanstack
nop
move $a0, $sp
So it was "helpfully" inserting a branch delay slot, even though this
was already being taken care of.
Somehow this didn't break, but it does break in the WIP threading branch
(https://github.com/tinygo-org/tinygo/pull/4559) where this bug leads to
a crash.
This uses uint32 instead of uint64. The reason for this is that uint64
atomic operations aren't universally available (especially on 32-bit
architectures). We could also use uintptr, but that seems needlessly
complicated: it's unlikely real-world programs will use more than a
billion select states (2^30).
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.
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 adds linux/mipsle (little endian Mips) support to TinyGo.
It also adds experimental linux/mips (big-endian) support. It doesn't
quite work yet, some parts of the standard library (like the reflect
package) currently seem to assume a little-endian system.
I managed to get CGo sort-of working in VSCode (meaning that it will
typecheck code in the IDE itself) using a few crude hacks, but it
requires a few minor changes to the TinyGo standard library.
I intend to eventually add this support in the TinyGo extension for
VSCode directly, but for now I've manually updated .vscode/settings.json
to get IDE support. In any case, it would be nice to have this for when
I hopefully add this to the TinyGo extension eventually.
The old code was broken and led to a HardFault in a rather convoluted
way:
1. The CFA offset was incorrect, in fact it was not aligned (the stack
is supposed to always be aligned to 4 bytes at least).
2. This unaligned size was then used for stack size calculations.
3. A stack that wasn't a multiple of 4 was allocated.
4. The calleeSavedRegs struct (in `(internal/task.state).archInit`) was
not correctly aligned.
5. Writing to this struct resulted in a HardFault.
Blocking inside an interrupt is always unsafe and will lead to all kinds
of bad behavior (even if it might appear to work sometimes). So disallow
it, just like allocating heap memory inside an interrupt is not allowed.
I suspect this will usually be caused by channel sends, like this:
ch <- someValue
The easy workaround is to make it a non-blocking send instead:
select {
case ch <- someValue:
default:
}
This does mean the application might become a bit more complex to be
able to deal with this case, but the alternative (undefined behavior) is
IMHO much worse.
Some vector registers must be preserved across calls, but this wasn't
happening on Linux and MacOS. When I added support for windows/arm64, I
saw that it required these vector registers to be preserved and assumed
this was Windows deviating from the standard calling convention. But
actually, Windows was just implementing the standard calling convention
and the bug was on Linux and MacOS.
This commit fixes the bug on Linux and MacOS and at the same time merges
the Go and assembly files as they no longer need to be separate.
This was actually surprising once I got TinyGo to build on Windows 11
ARM64. All the changes are exactly what you'd expect for a new
architecture, there was no special weirdness just for arm64.
Actually getting TinyGo to build was kind of involved though. The very
short summary is: install arm64 versions of some pieces of software
(like golang, cmake) instead of installing them though choco. In
particular, use the llvm-mingw[1] toolchain instead of using standard
mingw.
[1]: https://github.com/mstorsjo/llvm-mingw/releases
This implements the block-based GC as a partially precise GC. This means
that for most heap allocations it is known which words contain a pointer
and which don't. This should in theory make the GC faster (because it
can skip non-pointer object) and have fewer false positives in a GC
cycle. It does however use a bit more RAM to store the layout of each
object.
Right now this GC seems to be slower than the conservative GC, but
should be less likely to run out of memory as a result of false
positives.
--allow-undefined can be a problem: it allows compiling code that will
fail when loaded. This change makes sure that if some symbols are
undefined, they are reported as an error by the linker.
Previously, people could get away with importing a function that was not
defined, like this:
func add(int a, int b) int
func test() {
println(add(3, 5))
}
This was always unintended but mostly worked. With this change, it isn't
possible anymore. Now every function needs to be marked with //export
explicitly:
//export add
func add(int a, int b) int
func test() {
println(add(3, 5))
}
As before, functions will be placed in the `env` module with the name
set from the `//export` tag. This can be overridden with
`//go:import-module`:
//go:import-module math
//export add
func add(int a, int b) int
func test() {
println(add(3, 5))
}
For the syscall/js package, I needed to give a list of symbols that are
undefined. This list is based on the JavaScript functions defined in
targets/wasm_exec.js.
Go 1.19 started reformatting code in a way that makes it more obvious
how it will be rendered on pkg.go.dev. It gets it almost right, but not
entirely. Therefore, I had to modify some of the comments so that they
are formatted correctly.
Some source code wasn't part of `FMT_PATHS` so wasn't checked for
correct formatting. This change includes all this source code and
excludes cgo/testdata because it contains files that can't be parsed.
If an interrupt happens between the writes to SPL and SPH, the stack
pointer is inconsistent and terrible things will happen. Therefore,
disable interrupts while updating the stack pointer.
Interrupts are restored _before_ the write to SPH. This is safe, because
interrupts are re-enabled with a one cycle delay. The avr-gcc and Clang
compilers do the same thing when they need to update the stack pointer.
It's almost impossible to test for this bug, but it should make firmware
just a little bit more reliable.
This patch adds support for generating GOOS=darwin GOARCH=arm64
binaries. This means that it will become possible to run `go test` on
recent Macs, for example.
This adds support for building with `-tags=llvm13` and switches to LLVM
13 for tinygo binaries that are statically linked against LLVM.
Some notes on this commit:
* Added `-mfloat-abi=soft` to all Cortex-M targets because otherwise
nrfx would complain that floating point was enabled on Cortex-M0.
That's not the case, but with `-mfloat-abi=soft` the `__SOFTFP__`
macro is defined which silences this warning.
See: https://reviews.llvm.org/D100372
* Changed from `--sysroot=<root>` to `-nostdlib -isystem <root>` for
musl because with Clang 13, even with `--sysroot` some system
libraries are used which we don't want.
* Changed all `-Xclang -internal-isystem -Xclang` to simply
`-isystem`, for consistency with the above change. It appears to
have the same effect.
* Moved WebAssembly function declarations to the top of the file in
task_asyncify_wasm.S because (apparently) the assembler has become
more strict.
This change swaps the stack chain when switching goroutines, ensuring that the chain is maintained consistently.
This is only really currently necessary with asyncify on wasm.
The assembly symbols were not marked as hidden and so were exported,
leading to unreferenced symbols.
Example error message:
Error: failed to run main module `/tmp/tinygo3961039405/main`
Caused by:
0: failed to instantiate "/tmp/tinygo3961039405/main"
1: unknown import: `asyncify::stop_rewind` has not been defined
This commit fixes this issue.
Ayke van Laethem
Dan Kegel
dkegel-fastly
waj334
Justin A. Wilson
Anuraag Agrawal
Yurii Soldak
Nia Waldvogel
Damian Gryski