Since https://github.com/tinygo-org/tinygo/pull/1571 (in particular, the first
commit that sets the main package path), the main package is always named
"main". This makes the callMain() workaround in the runtime unnecessary and
allows directly calling the main.main function with a //go:linkname pragma.
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.
This commit swaps the layout of the heap. Previously, the metadata was
at the start and the data blocks (the actual heap memory) followed
after. This commit swaps those, so that the heap area starts with the
data blocks followed by the heap metadata.
This arrangement is not very relevant for baremetal targets that always
have all RAM allocated, but it is an important improvement for other
targets such as WebAssembly where growing the heap is possible but
starting with a small heap is a good idea. Because the metadata lives at
the end, and because the metadata does not contain pointers, it can
easily be moved. The data itself cannot be moved as the conservative GC
does not know all the pointer locations, plus moving the data could be
very expensive.
This commit changes the number of wait states for the stm32f103 chip to
2 instead of 4. This gets it back in line with the datasheet, but it
also has the side effect of breaking I2C. Therefore, another (seemingly
unrelated) change is needed: the i2cTimeout constant must be increased
to a higher value to adjust to the lower flash wait states - presumably
because the lower number of wait states allows the chip to run code
faster.
For a full explanation, see interp/README.md. In short, this rewrite is
a redesign of the partial evaluator which improves it over the previous
partial evaluator. The main functional difference is that when
interpreting a function, the interpretation can be rolled back when an
unsupported instruction is encountered (for example, an actual unknown
instruction or a branch on a value that's only known at runtime). This
also means that it is no longer necessary to scan functions to see
whether they can be interpreted: instead, this package now just tries to
interpret it and reverts when it can't go further.
This new design has several benefits:
* Most errors coming from the interp package are avoided, as it can
simply skip the code it can't handle. This has long been an issue.
* The memory model has been improved, which means some packages now
pass all tests that previously didn't pass them.
* Because of a better design, it is in fact a bit faster than the
previous version.
This means the following packages now pass tests with `tinygo test`:
* hash/adler32: previously it would hang in an infinite loop
* math/cmplx: previously it resulted in errors
This also means that the math/big package can be imported. It would
previously fail with a "interp: branch on a non-constant" error.
This has been a *lot* of work, trying to understand the Xtensa windowed
registers ABI. But in the end I managed to come up with a very simple
implementation that so far seems to work very well.
I tested this with both blinky examples (with blinky2 slightly edited)
and ./testdata/coroutines.go to verify that it actually works.
Most development happened on the ESP32 QEMU fork from Espressif
(https://github.com/espressif/qemu/wiki) but I also verified that it
works on a real ESP32.
The Cortex-M target isn't much changed, but much of the logic for the
AVR stack switcher that was previously in assembly has now been moved to
Go to make it more maintainable and in fact smaller in code size. Three
functions (tinygo_getCurrentStackPointer, tinygo_switchToTask,
tinygo_switchToScheduler) have been changed to one: tinygo_swapTask.
This reduction in assembly code should make the code more maintainable
and should make it easier to port stack switching to other
architectures.
I've also moved the assembly files to src/internal/task, which seems
like a more appropriate location to me.
* Heap allocation based on available ram
* Added homebrew launcher parser (for overriden heap)
* Removed unused stuff (moved to gonx)
* Kept require code at minimum to work in a real device
* Moved everything to a single file
This appears to be allowed by the specification, at least it is allowed
by the main Go implementation: https://play.golang.org/p/S8jxAMytKDB
Allow it in TinyGo too, for consistency.
Found because it is triggered with `tinygo test flags`. This doesn't
make the flags package pass all tests, but is a step closer.
It can be unexpected that printing a float32 involves 64-bit floating
point routines, see for example:
https://github.com/tinygo-org/tinygo/issues/1415
This commit adds a dedicated printfloat32 instead just for printing
float32 values. It comes with a possible code size increase, but only if
both float32 and float64 values are printed. Therefore, this should be
an improvement in almost all cases.
I also tried using printfloat32 for everything (and casting a float64 to
float32 to print) but the printed values are slightly different,
breaking the testdata/math.go test for example.
The only architecture that actually needs special support for scanning
the stack is WebAssembly. All others allow raw access to the stack with
a small bit of assembly. Therefore, don't manually keep track of all
these objects on the stack manually and instead just use conservative
stack scanning.
This results in a massive code size decrease in the affected targets
(only tested linux/amd64 for code size) - sometimes around 33%. It also
allows for future improvements such as using proper stackful goroutines.
Instead of putting tinygo_scanCurrentStack in scheduler_*.S files, put
them in dedicated files. The function tinygo_scanCurrentStack has
nothing to do with scheduling and so doesn't belong there. Additionally,
while scheduling code is made specific for the Cortex-M, the
tinygo_scanCurrentStack is generic to all ARM targets so this move
removes some duplication there.
Specifically:
* tinygo_scanCurrentStack is moved out of scheduler_cortexm.S as it
isn't really part of the scheduler. It is now gc_arm.S.
* Same for the AVR target.
* Same for the RISCV target.
* scheduler_gba.S is removed, using gc_arm.S instead as it only
contains tinygo_scanCurrentStack.
* initial commit for WASI support
* merge "time" package with wasi build tag
* override syscall package with wasi build tag
* create runtime_wasm_{js,wasi}.go files
* create syscall_wasi.go file
* create time/zoneinfo_wasi.go file as the replacement of zoneinfo_js.go
* add targets/wasi.json target
* set visbility hidden for runtime extern variables
Accodring to the WASI docs (https://github.com/WebAssembly/WASI/blob/master/design/application-abi.md#current-unstable-abi),
none of exports of WASI executable(Command) should no be accessed.
v0.19.0 of bytecodealliance/wasmetime, which is often refered to as the reference implementation of WASI,
does not accept any exports except functions and the only limited variables like "table", "memory".
* merge syscall_{baremetal,wasi}.go
* fix js target build
* mv wasi functions to syscall/wasi && implement sleepTicks
* WASI: set visibility hidden for globals variables
* mv back syscall/wasi/* to runtime package
* WASI: add test
* unexport wasi types
* WASI test: fix wasmtime path
* stop changing visibility of runtime.alloc
* use GOOS=linux, GOARCH=arm for wasi target
Signed-off-by: mathetake <takeshi@tetrate.io>
* WASI: fix build tags for os/runtime packages
Signed-off-by: mathetake <takeshi@tetrate.io>
* run WASI test only on Linux
Signed-off-by: mathetake <takeshi@tetrate.io>
* set InternalLinkage instead of changing visibility
Signed-off-by: mathetake <takeshi@tetrate.io>
For example, for running tests with -target=wasm or
-target=cortex-m-qemu. It looks at the output to determine whether tests
were successful in the absence of a status code.
The algorithm now checks for invalid UTF-8 sequences, which is required
by the Go spec.
This gets the tests of the unicode/utf8 package to pass.
Also add bytes.Equal for Go 1.11, which again is necessary for the
unicode/utf8 package.
There were a few problems with the go/packages package. While it is more
or less designed for our purpose, it didn't work quite well as it didn't
provide access to indirectly imported packages (most importantly the
runtime package). This led to a workaround that sometimes broke
`tinygo test`.
This PR contains a number of related changes:
* It uses `go list` directly to retrieve the list of packages/files to
compile, instead of relying on the go/packages package.
* It replaces our custom TestMain replace code with the standard code
for running tests (generated by `go list`).
* It adds a dummy runtime/pprof package and modifies the testing
package, to get tests to run again with the code generated by
`go list`.
This is only very minimal support. More support (such as tinygo flash,
or peripheral access) should be added in later commits, to keep this one
focused.
Importantly, this commit changes the LLVM repo from llvm/llvm-project to
tinygo-org/llvm-project. This provides a little bit of versioning in
case something changes in the Espressif fork. If we want to upgrade to
LLVM 11 it's easy to switch back to llvm/llvm-project until Espressif
has updated their fork.
This is a big change that will determine the stack size for many
goroutines automatically. Functions that aren't recursive and don't call
function pointers can in many cases have an automatically determined
worst case stack size. This is useful, as the stack size is usually much
lower than the previous hardcoded default of 1024 bytes: somewhere
around 200-500 bytes is common.
A side effect of this change is that the default stack sizes (including
the stack size for other architectures such as AVR) can now be changed
in the config JSON file, making it tunable per application.
This reduces current consumption from 500-1000µA to very low (<10µA)
current consumption. This change is important for battery powered
devices, especially devices that may be running for long periods of
time.
Call Frame Information is stored in the .debug_frame section and is used
by debuggers for unwinding. For assembly, this information is not known.
Debuggers will normally use heuristics to figure out the parent function
in the absence of call frame information.
This usually works fine, but is not enough for determining stack sizes.
Instead, I hardcoded the stack size information in
stacksize/stacksize.go, which is somewhat fragile. This change uses CFI
assembly directives to store this information instead of hardcoding it.
This change also fixes the following error message that would appear in
GDB:
Backtrace stopped: previous frame identical to this frame (corrupt stack?)
More information on CFI:
* https://sourceware.org/binutils/docs/as/CFI-directives.html
* https://www.imperialviolet.org/2017/01/18/cfi.html
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.
