PR #5220 changed -print-allocs output to the go coverage tool format, which
replaced the original human-readable explanation of why each object had to be
heap allocated. That explanation is useful on its own, so this restores it as
the default behavior of -print-allocs and moves the coverage format behind a
-print-allocs-cover flag.
Signed-off-by: Piotr Bocheński <piotr@bochen.ski>
* interp: bail out of loops that iterate too many times
The existing loop guard (errLoopUnrolled) only fires when a loop body
emits runtime instructions. Loops that are fully evaluable at compile
time, such as inserting thousands of entries into a map, were not
caught and could hang the compiler.
Add a per-basic-block iteration counter that triggers a recoverable
error (errLoopTooLong) when any block is entered more than 1000 times
in a single function call. This defers the init function to runtime,
which is the same behavior as other interp bailouts.
Profiling showed that 83% of CPU time was spent in GC, caused by
allocation pressure from the interp memory cloning on each map
mutation. The iteration limit avoids this entirely by bailing out
before the quadratic cost becomes significant.
Performance on the reproducer from #2090 (map init with strconv.Itoa):
entries before after
5,000 7.4s 2.1s
10,000 17.5s 2.1s
20,000 48.0s 2.8s
65,536 >180s (OOM) 3.2s
* Add -interp-loop-limit
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.
This changes the -json flag for build/run/flash/gdb etc commands to not
print `compileopts.Config` but instead match upstream Go and print build
errors in a structured way.
For more details, see the proposal:
https://github.com/golang/go/issues/62067
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 adds support for the well-known Boehm GC. It's significantly faster
than our own naive GC and could be used as an alternative on bigger
systems.
In the future, this GC might also be supported on WebAssembly with some
extra work. Right now it's Linux only (though Windows/MacOS shouldn't be
too difficult to add).
older behavior for wasi modules to not return an exit code as if they were reactors.
See #4726 for some details on what this is intended to address.
Signed-off-by: deadprogram <ron@hybridgroup.com>
This is not a big change over the existing size report with -size=full,
but it is a bit more readable.
More information will be added in subsequent commits.
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.
Previously, the compiler would default to hardfloat. This is not
supported by some MIPS CPUs.
This took me much longer than it should have because of a quirk in the
LLVM Mips backend: if the target-features string is not set (like during
LTO), the Mips backend picks the first function in the module and uses
that. Unfortunately, in the case of TinyGo this first function is
`llvm.dbg.value`, which is an LLVM intrinsic and doesn't have the
target-features string. I fixed it by adding a `-mllvm -mattr=` flag to
the linker.
This fixes the new loop variable behavior in Go 1.22.
Specifically:
* The compiler (actually, the x/tools/go/ssa package) now correctly
picks up the Go version.
* If a module doesn't specify the Go version, the current Go version
(from the `go` tool and standard library) is used. This fixes
`go run`.
* The tests in testdata/ that use a separate directory are now
actually run in that directory. This makes it possible to use a
go.mod file there.
* There is a test to make sure old Go modules still work with the old
Go behavior, even on a newer Go version.
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.
This flag controls whether to convert external i64 parameters for use in
a browser-like environment.
This flag was needed in the past because back then we only supported
wasm on browsers but no WASI. Now, I can't think of a reason why anybody
would want to change the default. For `-target=wasm` (used for
browser-like environments), the wasm_exec.js file expects this
i64-via-stack ABI. For WASI, there is no limitation on i64 values and
`-wasm-abi=generic` is the default.
This should add support for things like quotes around tags, if they are
ever needed.
Only making this change now because I happened to stumble across
buildutil.TagsFlag.
Switching to a shared semaphore allows multi-build operations (compiler tests, package tests, etc.) to use the expected degree of parallelism efficiently.
While refactoring the job runner, the time complexity was also reduced from O(n^2) to O(n+m) (where n is the number of jobs, and m is the number of dependencies).
The extalloc collector has been broken for a while, and it doesn't seem reasonable to fix right now.
In addition, after a recent change it no longer compiles.
In the future similar functionality can hopefully be reintroduced, but for now this seems to be the most reasonable option.
This environment variable can be set to 5, 6, or 7 and controls which
ARM version (ARMv5, ARMv6, ARMv7) is used when compiling for GOARCH=arm.
I have picked the default value ARMv6, which I believe is supported on
most common single board computers including all Raspberry Pis. The
difference in code size is pretty big.
We could even go further and support ARMv4 if anybody is interested. It
should be pretty simple to add this if needed.
This change implements a new "scheduler" for WebAssembly using binaryen's asyncify transform.
This is more reliable than the current "coroutines" transform, and works with non-Go code in the call stack.
runtime (js/wasm): handle scheduler nesting
If WASM calls into JS which calls back into WASM, it is possible for the scheduler to nest.
The event from the callback must be handled immediately, so the task cannot simply be deferred to the outer scheduler.
This creates a minimal scheduler loop which is used to handle such nesting.
... instead of setting a special -target= value. This is more robust and
makes sure that the test actually tests different arcitectures as they
would be compiled by TinyGo. As an example, the bug of the bugfix in the
previous commit ("arm: use armv7 instead of thumbv7") would have been
caught if this change was applied earlier.
I've decided to put GOOS/GOARCH in compileopts.Options, as it makes
sense to me to treat them the same way as command line parameters.
This can be very useful for some purposes:
* It makes it possible to disable the UART in cases where it is not
needed or needs to be disabled to conserve power.
* It makes it possible to disable the serial output to reduce code
size, which may be important for some chips. Sometimes, a few kB can
be saved this way.
* It makes it possible to override the default, for example you might
want to use an actual UART to debug the USB-CDC implementation.
It also lowers the dependency on having machine.Serial defined, which is
often not defined when targeting a chip. Eventually, we might want to
make it possible to write `-target=nrf52` or `-target=atmega328p` for
example to target the chip itself with no board specific assumptions.
The defaults don't change. I checked this by running `make smoketest`
before and after and comparing the results.
With this is possible to enable e.g., SIMD in WASM using -llvm-features
+simd128. Multiple features can be specified separated by comma,
e.g., -llvm-features +simd128,+tail-call
With help from @deadprogram and @aykevl.
This flag, if set, is a regexp for function names. If there are heap
allocations in the matching function names, these heap allocations will
be printed with an explanation why the heap allocation exists (and why
the object can't be stack allocated).
This commit implements replacing some global variables with a different
value, if the global variable has no initializer. For example, if you
have:
package main
var version string
you can replace the value with -ldflags="-X main.version=0.2".
Right now it only works for uninitialized globals. The Go tooling also
supports initialized globals (var version = "<undefined>") but that is a
bit hard to combine with how initialized globals are currently
implemented.
The current implementation still allows caching package IR files while
making sure the values don't end up in the build cache. This means
compiling a program multiple times with different values will use the
cached package each time, inserting the string value only late in the
build process.
Fixes#1045
This simplifies future changes. While the move itself is very simple, it
required some other changes to a few transforms that create new
functions to add the optsize attribute manually. It also required
abstracting away the optimization level flags (based on the -opt flag)
so that it can easily be retrieved from the config object.
This commit does not impact binary size on baremetal and WebAssembly.
I've seen a few tests on linux/amd64 grow slightly in size, but I'm not
too worried about those.
On WebAssembly it is possible to grow the heap with the memory.grow
instruction. This commit implements this feature and with that also
removes the -heap-size flag that was reportedly broken (I haven't
verified that). This should make it easier to use TinyGo for
WebAssembly, where there was no good reason to use a fixed heap size.
This commit has no effect on baremetal targets with optimizations
enabled.
For now, this is just an extra flag that can be used to print stack
frame information, but this is intended to provide a way to determine
stack sizes for goroutines at compile time in many cases.
Stack sizes are often somewhere around 350 bytes so are in fact not all
that big usually. Once this can be determined at compile time in many
cases, it is possible to use this information when available and as a
result increase the fallback stack size if the size cannot be determined
at compile time. This should reduce stack overflows while at the same
time reducing RAM consumption in many cases.
Interesting output for testdata/channel.go:
function stack usage (in bytes)
Reset_Handler 332
.Lcommand-line-arguments.fastreceiver 220
.Lcommand-line-arguments.fastsender 192
.Lcommand-line-arguments.iterator 192
.Lcommand-line-arguments.main$1 184
.Lcommand-line-arguments.main$2 200
.Lcommand-line-arguments.main$3 200
.Lcommand-line-arguments.main$4 328
.Lcommand-line-arguments.receive 176
.Lcommand-line-arguments.selectDeadlock 72
.Lcommand-line-arguments.selectNoOp 72
.Lcommand-line-arguments.send 184
.Lcommand-line-arguments.sendComplex 192
.Lcommand-line-arguments.sender 192
.Lruntime.run$1 548
This shows that the stack size (if these numbers are correct) can in
fact be determined automatically in many cases, especially for small
goroutines. One of the great things about Go is lightweight goroutines,
and reducing stack sizes is very important to make goroutines
lightweight on microcontrollers.
Jake Bailey
Piotr Bocheński
sivchari
Ayke van Laethem
Damian Gryski
deadprogram
Anuraag Agrawal
sago35
Nia Waldvogel
Federico G. Schwindt
Kenneth Bell
Fauchon