0.27.0

This release adds support for Go 1.20 and LLVM 15. In addition, it drops a dependency on the AVR and Xtensa toolchains, so you don't need to install avr-gcc or xtensa-esp32-elf-ld making TinyGo much easier to install. Instead, it uses the built-in LLVM linker instead.
Newly supported targets are windows/arm64 (or "Windows on ARM64"), Waveshare RP2040 Zero, Arduino Leonardo, Adafruit KB2040, Adafruit Feather M0 Express, Makerfabs ESP32C3SPI35, and Espressif ESP32-C3-DevKit-RUST-1. As usual, there are also a ton of smaller fixes and improvements.

Here is a detailed changelog for this release:

• general
  • all: update musl
  • all: remove "acm:"` prefix for USB vid/pid pair
  • all: add support for LLVM 15
  • all: use DWARF version 4
  • all: add initial (incomplete) support for Go 1.20
  • all: add -gc=custom option
  • main: print ldflags including ThinLTO flags with -x
  • main: fix error message when a serial port can't be accessed
  • main: add -timeout flag to allow setting how long TinyGo will try looking for a MSD volume for flashing
  • test: print PASS on pass when running standalone test binaries
  • test: fix printing of benchmark output
  • test: print package name when compilation failed (not just when the test failed)
• compiler
  • refactor to support LLVM 15
  • builder: print compiler commands while building a library
  • compiler: fix stack overflow when creating recursive pointer types (fix for LLVM 15+ only)
  • compiler: allow map keys and values of ≥256 bytes
  • cgo: add support for C.float and C.double
  • cgo: support anonymous enums included in multiple Go files
  • cgo: add support for bitwise operators
  • interp: add support for constant icmp instructions
  • transform: fix memory corruption issues
• standard library
  • machine/usb: remove allocs in USB ISR
  • machine/usb: add Port() and deprecate New() to have the API better match the singleton that is actually being returned
  • machine/usb: change HID usage-maximum to 0xFF
  • machine/usb: add USB HID joystick support
  • machine/usb: change to not send before endpoint initialization
  • net: implement Pipe
  • os: add stub for os.Chtimes
  • reflect: stub out Type.FieldByIndex
  • reflect: add Value.IsZero method
  • reflect: fix bug in .Field method when the field fits in a pointer but the parent doesn't
  • runtime: switch some panic() calls in the gc to runtimePanic() for consistency
  • runtime: add xorshift-based fastrand64
  • runtime: fix alignment for arm64, arm, xtensa, riscv
  • runtime: implement precise GC
  • runtime/debug: stub PrintStack
  • sync: implement simple pooling in sync.Pool
  • syscall: stubbed Setuid, Exec and friends
  • syscall: add more stubs as needed for Go 1.20 support
  • testing: implement t.Setenv
  • unsafe: add support for Go 1.20 slice/string functions
• targets
  • all: do not set stack size per board
  • all: update picolibc to v1.7.9
  • atsame5x: fix CAN extendedID handling
  • atsame5x: reduce heap allocation
  • avr: drop GNU toolchain dependency
  • avr: fix .data initialization for binaries over 64kB
  • avr: support ThinLTO
  • baremetal: implements calloc
  • darwin: fix syscall.Open on darwin/arm64
  • darwin: fix error with tinygo lldb
  • esp: use LLVM Xtensa linker instead of Espressif toolchain
  • esp: use ThinLTO for Xtensa
  • esp32c3: add SPI support
  • linux: include musl getpagesize function in release
  • nrf51: add ADC implementation
  • nrf52840: add PDM support
  • riscv: add "target-abi" metadata flag
  • rp2040: remove mem allocation in GPIO ISR
  • rp2040: avoid allocating clock on heap
  • rp2040: add basic GPIO support for PIO
  • rp2040: fix USB interrupt issue
  • rp2040: fix RP2040-E5 USB errata
  • stm32: always set ADC pins to pullups floating
  • stm32f1, stm32f4: fix ADC by clearing the correct bit for rank after each read
  • stm32wl: Fix incomplete RNG initialisation
  • stm32wlx: change order for init so clock speeds are set before peripheral start
  • wasi: makes wasmtime "run" explicit
  • wasm: fix GC scanning of allocas
  • wasm: allow custom malloc implementation
  • wasm: remove -wasm-abi= flag (use -target instead)
  • wasm: fix scanning of the stack
  • wasm: fix panic when allocating 0 bytes using malloc
  • wasm: always run wasm-opt even with -scheduler=none
  • wasm: avoid miscompile with ThinLTO
  • wasm: allow the emulator to expand {tmpDir}
  • wasm: support ThinLTO
  • windows: update mingw-w64 version to avoid linker warning
  • windows: add ARM64 support
• boards
  • Add Waveshare RP2040 Zero
  • Add Arduino Leonardo support
  • Add Adafruit KB2040
  • Add Adafruit Feather M0 Express
  • Add Makerfabs ESP32C3SPI35 TFT Touchscreen board
  • Add Espressif ESP32-C3-DevKit-RUST-1 board
  • lgt92: fix OpenOCD configuration
  • xiao-rp2040: fix D9 and D10 constants
  • xiao-rp2040: add pin definitions