Using ThinLTO manages to optimize binaries quite significantly. The
exact amount varies a lot by program but it's about 10-15% usually.
Don't remove non-ThinLTO support yet. It would not surprise me if this
triggered some unintended side effect. Eventually, non-ThinLTO support
should be removed though.
This allows you to expand {tmpDir} in the json "emulator" field, and
uses it in wasmtime instead of custom TMPDIR mapping logic.
Before, we had custom logic for wasmtime to create a separate tmpDir
when running go tests. This overwrite the TMPDIR variable when running,
after making a mount point. A simpler way to accomplish the end goal of
writing temp files is to use wasmtime's map-dir instead. When code is
compiled to wasm with the wasi target, tempDir is always /tmp, so we
don't need to add variables (since we know what it is). Further, the
test code is the same between normal go and run through wasmtime. So, we
don't need to make a separate temp dir first, and avoiding that reduces
logic, as well makes it easier to swap out the emulator (for wazero
which has no depedencies). To map the correct directory, this introduces
a {tmpDir} token whose value is the host-specific value taken from
`os.TempDir()`.
The motivation I have for this isn't so much to clean up the wasmtime
code, but allow wazero to execute the same tests. After this change, the
only thing needed to pass tests is to change the emulator, due to
differences in how wazero deals with relative lookups (they aren't
restricted by default, so there's not a huge amount of custom logic
needed).
In other words, installing wazero from main, `make tinygo-test-wasi`
works with no other changes except this PR and patching
`targets/wasi.json`.
```json
"emulator": "wazero run -mount=.:/ -mount={tmpDir}:/tmp {}",
```
On that note, if there's a way to override the emulator via arg or env,
this would be even better, but in any case patching json is fine.
Signed-off-by: Adrian Cole <adrian@tetrate.io>
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.
ThinLTO results in a small code size reduction, which is nice
(especially on these very small chips). It also brings us one step
closer to using ThinLTO everywhere.
This reverts commit 0b3a7280fa and updates
the documentation a little bit to explain the purpose of -gc=none. (I'm
thinking about the attiny10 by the way where defaulting to -gc=none
makes sense).
This is now possible because we're using the LLVM linker. It results in
some very minor code size reductions. The main benefit however is
consistency: eventually, all targets will support ThinLTO at which point
we can remove support for GNU linkers and simplify the compiler.
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 hopefully fix the following issue:
DW_FORM_rnglistx index pointing outside of .debug_rnglists offset array [in module /tmp/tinygo4013272868/main]
This flag is necessary in LLVM 15 because it appears that LLVM 15 has
changed the default target ABI from lp64 to lp64d. This results in a
linker failure. Setting the "target-abi" forces the RISC-V backend to
use the intended target ABI.
Before, on the baremetal target or MacOS, we errored if the user
provided configuration to strip debug info.
Ex.
```bash
$ $ tinygo build -o main.go -scheduler=none --no-debug main.go
error: cannot remove debug information: MacOS doesn't store debug info in the executable by default
```
This is a poor experience which results in having OS-specific CLI
behavior. Silently succeeding is good keeping with the Linux philosophy
and less distracting than logging the same without failing.
Signed-off-by: Adrian Cole <adrian@tetrate.io>
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.
This matches the flash-command and is generally a bit easier to work
with.
This commit also prepares for allowing multiple formats to be used in
the emulator command, which is necessary for the esp32.
Without this patch, the include directory isn't found and picolibc.h
(used indirectly by stdint.h for example) can't be found.
I would like to add tests for this but we currently don't run Xtensa
tests. This should be possible however using https://github.com/espressif/qemu/wiki
(see also: https://github.com/tinygo-org/tinygo/pull/2780).
ThinLTO optimizes across LLVM modules at link time. This means that
optimizations (such as inlining and const-propagation) are possible
between C and Go. This makes this change especially useful for CGo, but
not just for CGo. By doing some optimizations at link time, the linker
can discard some unused functions and this leads to a size reduction on
average. It does increase code size in some cases, but that's true for
most optimizations.
I've excluded a number of targets for now (wasm, avr, xtensa, windows,
macos). They can probably be supported with some more work, but that
should be done in separate PRs.
Overall, this change results in an average 3.24% size reduction over all
the tinygo.org/x/drivers smoke tests.
TODO: this commit runs part of the pass pipeline twice. We should set
the PrepareForThinLTO flag in the PassManagerBuilder for even further
reduced code size (0.7%) and improved compilation speed.
This means that it will be possible to generate a Darwin binary on any
platform (Windows, Linux, and MacOS of course), including CGo. Of
course, the resulting binaries can only run on MacOS itself.
The binary links against libSystem.dylib, which is a shared library. The
macos-minimal-sdk repository contains open source header files and
generated symbol stubs so we can generate a stub libSystem.dylib without
copying any closed source code.
This subcommand has been broken for a while, since libraries also use
the CPU flag. This commit fixes this.
Previously, libraries were usable for most Cortex-M cores. But with the
addition of the CPU field, I've limited it to three popular cores: the
Cortex-M0 (microbit), Cortex-M0+ (atsamd21), and Cortex-M4 (atsamd21,
nrf52, and many others).
In the future we might consider also building libraries for the current
OS/arch so that libraries like musl are already precompiled.
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.
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.
This makes sure that the LLVM target features match the one generated by
Clang:
- This fixes a bug introduced when setting the target CPU for all
targets: Cortex-M4 would now start using floating point operations
while they were disabled in C.
- This will make it possible in the future to inline C functions in Go
and vice versa. This will need some more work though.
There is a code size impact. Cortex-M4 targets are increased slightly in
binary size while Cortex-M0 targets tend to be reduced a little bit.
Other than that, there is little impact.
This commit adds support for musl-libc and uses it by default on Linux.
The main benefit of it is that binaries are always statically linked
instead of depending on the host libc, even when using CGo.
Advantages:
- The resulting binaries are always statically linked.
- No need for any tools on the host OS, like a compiler, linker, or
libc in a release build of TinyGo.
- This also simplifies cross compilation as no cross compiler is
needed (it's all built into the TinyGo release build).
Disadvantages:
- Binary size increases by 5-6 kilobytes if -no-debug is used. Binary
size increases by a much larger margin when debugging symbols are
included (the default behavior) because musl is built with debugging
symbols enabled.
- Musl does things a bit differently than glibc, and some CGo code
might rely on the glibc behavior.
- The first build takes a bit longer because musl needs to be built.
As an additional bonus, time is now obtained from the system in a way
that fixes the Y2038 problem because musl has been a bit more agressive
in switching to 64-bit time_t.
This is really just a preparatory commit for musl support. The idea is
to store not just the archive file (.a) but also an include directory.
This is optional for picolibc but required for musl, so the main purpose
of this commit is the refactor needed for this change.
This brings a bit more consistency to libc configuration. It seems
better to me to set the header flags all in the same place, instead of
some in Go code and some in JSON target files (depending on the target).
This is for consistency with Clang, which always adds a CPU flag even if
it's not specified in CFLAGS.
This commit also adds some tests to make sure the Clang target-cpu
matches the CPU property in the JSON files.
This does have an effect on the generated binaries. The effect is very
small though: on average just 0.2% increase in binary size, apparently
because Cortex-M3 and Cortex-M4 are compiled a bit differently. However,
when rebased on top of https://github.com/tinygo-org/tinygo/pull/2218
(minsize), the difference drops to -0.1% (a slight decrease on average).
This adds support for stdio in picolibc and fixes wasm_exec.js so that
it can also support C puts. With this, C stdout works on all supported
platforms.
This commit changes a target triple like "armv6m-none-eabi" to
"armv6m-unknown-unknow-eabi". The reason is that while the former is
correctly parsed in Clang (due to normalization), it wasn't parsed
correctly in LLVM meaning that the environment wasn't set to EABI.
This change normalizes all target triples and uses the EABI environment
(-eabi in the triple) for Cortex-M targets.
This change also drops the `--target=` flag in the target JSON files,
the flag is now added implicitly in `(*compileopts.Config).CFlags()`.
This removes some duplication in target JSON files.
Unfortunately, this change also increases code size for Cortex-M
targets. It looks like LLVM now emits calls like __aeabi_memmove instead
of memmove, which pull in slightly more code (they basically just call
the regular C functions) and the calls themself don't seem to be as
efficient as they could be. Perhaps this is a LLVM bug that will be
fixed in the future, as this is a very common occurrence.
This brings some consistency to the CFlags and fixes the issue that on
some platforms (Linux, MacOS), no optimization level was set and
therefore C files in packages were not optimized at all.
Stripping debug information at link time also allows relocation
compression (aka linker relaxations). Keeping debug information at
compile time and optionally stripping it at link time has some
advantages:
* Automatic stack sizes on Cortex-M rely on the presence of debug
information.
* Some parts of the compiler now rely on the presence of debug
information for proper diagnostics.
* It works better with the cache: there is no distinction between
debug and no-debug builds.
* It makes it easier (or possible at all) to enable debug information
in the wasi-libc library without big downsides.
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.
The wasm build tag together with GOARCH=arm was causing problems in the
internal/cpu package. In general, I think having two architecture build
tag will only cause problems (in this case, wasm and arm) so I've
removed the wasm build tag and replaced it with tinygo.wasm.
This is similar to the tinygo.riscv build tag, which is used for older
Go versions that don't yet have RISC-V support in the standard library
(and therefore pretend to be GOARCH=arm instead).
Damian Gryski
Ayke van Laethem
Anuraag Agrawal
Adrian Cole
sago35
Nia Waldvogel
Olivier Fauchon
Federico G. Schwindt