111 строки
4 КиБ
Markdown
111 строки
4 КиБ
Markdown
# TinyGo - Go compiler for microcontrollers
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[](https://tinygo.readthedocs.io/)
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[](https://travis-ci.com/aykevl/tinygo)
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> We never expected Go to be an embedded language and so it's got serious
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> problems [...].
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-- Rob Pike, [GopherCon 2014 Opening Keynote](https://www.youtube.com/watch?v=VoS7DsT1rdM&feature=youtu.be&t=2799)
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TinyGo is a project to bring Go to microcontrollers and small systems with a
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single processor core. It is similar to [emgo](https://github.com/ziutek/emgo)
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but a major difference is that I want to keep the Go memory model (which implies
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garbage collection of some sort). Another difference is that TinyGo uses LLVM
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internally instead of emitting C, which hopefully leads to smaller and more
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efficient code and certainly leads to more flexibility.
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My original reasoning was: if [Python](https://micropython.org/) can run on
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microcontrollers, then certainly [Go](https://golang.org/) should be able to and
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run on even lower level micros.
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Example program (blinky):
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```go
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import (
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"machine"
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"time"
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)
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func main() {
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led := machine.GPIO{machine.LED}
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led.Configure(machine.GPIOConfig{Mode: machine.GPIO_OUTPUT})
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for {
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led.Low()
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time.Sleep(time.Millisecond * 1000)
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led.High()
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time.Sleep(time.Millisecond * 1000)
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}
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}
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```
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Currently supported features:
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* control flow
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* many (but not all) basic types: most ints, floats, strings, structs
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* function calling
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* interfaces for basic types (with type switches and asserts)
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* goroutines (very initial support)
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* function pointers (non-blocking)
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* interface methods
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* standard library (but most packages won't work due to missing language
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features)
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* slices (partially)
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* maps (very rough, unfinished)
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* defer
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* closures
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* bound methods
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Not yet supported:
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* complex numbers
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* garbage collection
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* recover
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* channels
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* introspection (if it ever gets implemented)
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* ...
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## Supported targets
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Most targets that are supported by LLVM should be supported by this compiler.
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This means amd64 (where most of the testing happens), ARM, and Cortex-M
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microcontrollers.
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The AVR platform (as used by the Arduino, for example) is also supported when
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support for it is enabled in LLVM. However, because it is a Harvard style
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architecture with different address spaces for code and data and because LLVM
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turns globals into const for you (moving them to
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[PROGMEM](https://www.nongnu.org/avr-libc/user-manual/pgmspace.html)) most real
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programs don't work unfortunately. This can be fixed but that can be difficult
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to do efficiently and hasn't been implemented yet.
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## Analysis and optimizations
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The goal is to reduce code size (and increase performance) by performing all
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kinds of whole-program analysis passes. The official Go compiler doesn't do a
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whole lot of analysis (except for escape analysis) becauses it needs to be fast,
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but embedded programs are necessarily smaller so it becomes practical. And I
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think especially program size can be reduced by a large margin when actually
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trying to optimize for it.
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Implemented compiler passes:
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* Analyse which functions are blocking. Blocking functions are functions that
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call sleep, chan send, etc. Its parents are also blocking.
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* Analyse whether the scheduler is needed. It is only needed when there are
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`go` statements for blocking functions.
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* Analyse whether a given type switch or type assert is possible with
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[type-based alias analysis](https://en.wikipedia.org/wiki/Alias_analysis#Type-based_alias_analysis).
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I would like to use flow-based alias analysis in the future, if feasible.
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* Do basic dead code elimination of functions. This pass makes later passes
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better and probably improves compile time as well.
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## Building
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See the [installation instructions](https://tinygo.readthedocs.io/en/latest/installation.html).
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## License
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This project is licensed under the BSD 3-clause license, just like the
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[Go project](https://golang.org/LICENSE) itself.
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