tinygo-org/tinygo v0.40.0

0.40.0

on GitHub

Our final release for 2025 includes a number of really excellent improvements to close out the year. We have plenty of bugfixes and stability enhancements to make your life better and easier. For example, new updates to the GC that are up to 10% faster! Not to mention fixing some very tricky race conditions. Of course we have new hardware support, like the Xiao ESP32-S3 board.

• general
  • all: add full LLVM 20 support
  • core: feat: enable //go:linkname pragma for globals
  • core: feature: Add flag to ignore go compatibility matrix (#5078)
• compiler
  • emit an error when the actual arch doesn't match GOARCH
  • mark string parameters as readonly
  • use Tarjan's SCC algorithm to detect loops for defer
  • lower "large stack" limit to 16kb
• core
  • shrink bdwgc library
  • Fix linker errors for runtime.vgetrandom and crypto/internal/sysrand.fatal
  • fix: add TryLock to sync.RWMutex
  • fix: correct linter issues exposed by the fix in #4679
  • fix: don't hardcode success return state
  • fix: expand RTT debugger compatibility
  • internal/task (threads): save stack bounds instead of scanning under a lock
  • internal/task: create detached threads and fix error handling
  • interp: better errors when debugging interp
  • transform (gc): create stack slots in callers of external functions
  • internal/task: prevent semaphore resource leak for threads scheduler
• machine
  • cortexm: optimize code size for the HardFault_Handler
  • fe310: add I2C pins for the HiFive1b
  • clarify WriteAt semantics of BlockDevice
  • fix deprecated AsmFull comment (#5005)
  • make sure DMA buffers do not escape unnecessarily
  • only enable USB-CDC when needed
  • use larger SPI MAXCNT on nrf52833 and nrf52840
  • fix: update m.queuedBytes when clamping output to avoid corrupting sentBytes
  • fix: use int64 in ReadTemperature to avoid overflow
  • fix(rp2): disable DBGPAUSE on startup
  • fix(rp2): possible integer overflow while computing factors for SPI baudrate
  • fix(rp2): reset spinlocks at startup
  • fix(rp2): switch spinlock busy loop to wfe
  • fix(rp2): use side-effect-free spinlocks
  • nrf: add ADC_VDDH which is an ADC pin for VDDH
  • nrf: don't block SPI transfer
  • nrf: don't set PSELN, it's ignored in single ended mode anyway
  • nrf: fix typo in ADC configuration
  • nrf: refactor SoftDevice enabled check
  • nrf: rename pwmPin to adcPin
  • nrf: support flash operations while the SoftDevice is enabled
  • rp2040: allow writing to the UART inside interrupts
  • machine,nrf528: stop the bus only once on I2C bus error and ensures the first error is returned
• net
  • update submodule to latest commits
• runtime
  • (avr): fix infinite longjmp loop if stack is aligned to 256 bytes
  • (gc_blocks.go): clear full size of allocation
  • (gc_blocks.go): make sweep branchless
  • (gc_blocks.go): simplify scanning logic
  • (gc_blocks.go): use a linked stack to scan marked objects
  • (gc_blocks.go): use best-fit allocation
  • (gc_boehm.go): fix world already stopped check
  • (wasm): scan the system stack
  • fix sleep duration for long sleeps
  • remove copied code for nrf52840
  • src/syscall: update src buffer after write
  • wasm: fix C realloc and optimize it a bit
• targets
  • add xiao-esp32s3 board target
  • Add ESP32-S3 support (#5091)
  • Added Gopher ARCADE board
  • Create "pico2-ice" target board (#5062)
• build/test
  • Add testing.T.Context() and testing.B.Context()
  • create separate go.mod file for testing dependencies for wasm tests that use Chromium headless browser to avoid use of older incompatible version.
  • go back to normal scheduler instead of tasks scheduler for macos CI
  • update CI to use Go 1.25.5
  • update macOS GH actions builds to handle sunset of macOS 13
  • use task scheduler on macOS builds to avoid test race condition lockups
  • update all CI builds to use latest stable Go release. Also update some of the actions to their latest releases.
  • update GH actions builds to use Go 1.25.4
  • uninstall cmake before install
  • fix: point the submodule for musl-lib to a mirror in the TinyGo GitHub org
  • fix: remove macOS 15 from CI build matrix (conflicts with macOS 14 build)
  • fix: separate host expected bytes from device intended bytes
  • fix/typo: makeESPFirmwareImage
  • make: GNUmakefile: shrink TinyGo binaries on Linux
  • move the directory list into a variable
  • several improvements to the macOS GH actions build
  • Fix for #4678: top-level 'make lint' wasn't working
  • fix: increase the timeout for chromedp to connect to the headless browser used for running the wasm tests.
  • testdata: some more packages for the test corpus