* Build boot_stage2 with Bazel Introduces the initial foundations of a Bazel build, including a toolchain, critical generated headers, platform patterns, and enough BUILD files to build boot_stage2. * Bazel libraries to support picotool * Move SDK defines to toolchain * Switch to `archive_override` in MODULE.bazel Uses archive_override where applicable to allow transitive bzlmod deps to propagate. * Multiplatform objcopy selection in Bazel build Makes an objcopy alias that redirects to the objcopy tool for the current exec platform, which allows boot_stage2 to build on Linux, macOS, and Windows. * Generate Bazel build files Adds initial set of generated Bazel build files. Note that these do not yet build, as dependency cycles are present. * Fix dependency cycles in Bazel build Fixes many dependency cycles, some were unintentionally created by the build file generator, others are true dependency cycles that require manual workarounds. * Silence warning in pico_stdio Bazel build Silences a stray warning in the Bazel build. * Fix wildcard Bazel build This makes `bazel build //...` succeed, and also prevents the fetching of toolchains that aren't compatible with the current execution environment (i.e. Windows computers will no longer try to download macOS toolchains). * Get the SDK working Finishes out the remainder of the work required to successfully compile a working blinky example. * Fix UART stdio dependencies in Bazel build Fixes some dependencies around pico_stdlib so that pico_stdlib links properly and UART stdio works. * Add linux support to Bazel build * Get Bazel deps from registry Adds external an external registry for resolving Bazel module dependencies. * Fix host configuration for picotool Provides the appropriate defines for host builds to support the picotool build. * Remove -ffreestanding from Bazel toolchain The -ffreestanding toolchain flag is quite strict, so remove it from the Bazel toolchain. * Remove unused .bzl file * Reduce Bazel compiler flags Cuts out most of the Bazel toolchain flags and only specifies the bare-minimum set of flags. Also, adds wrapper linker flags for functions the SDK wraps. * Get USB serial working Adds initial TinyUSB support and enough integration to get USB serial working. * Remove "Generated build file" Removes comments that indicates BUILD.bazel files are generated. This was used during initial bringup to indicate hand-crafted vs automatically generated BUILD.bazel files. * Do not build USB libraries unless configured Prevents USB libraries from being built unless the build is properly configured to use them. * Switch to rules_cc toolchains Moves toolchain configuration to use the new rules in rules_cc. * Minor cleanup in parse_version.py Cleans up trailing whitespace and runs the black formatter on parse_version.py. * Simplify constraint dimensions in Bazel build Consolidates the class/chip constraint settings to be a single constraint_setting with a config_setting that represents the rp2 class. * Update pin of rules_cc in Bazel build Includes a necessary fix for the target_compatible_with expression in the cc_toolchain to work as intended. * Move toolchains from pico.bzl to BUILD.bazel Moves toolchain definitions from pico.bzl to BUILD.bazel to make them easier to find and read. * Run buildifier on Bazel build files Fix trivial formatting issues by running buildifier on all BUILD.bazel files. * Make objcopy rule Makes a simple objcopy rule to remove direct references to the ARM toolchains. * Fix link flags in Bazel build Critical flags were not being applied to link steps. This applies -mcpu and -mthumb to the link steps to make the produced binaries work again. * Mention missing host build support * Fix various Bazel library rules * pico_bit_ops was incomplete. * pico_double and pico_float were trying to link in the "none" implementation. * Extend Bazel build documentation Improves documentation and comments across the Bazel build. * Clean up auxilary tools in Bazel build Switches genrules to use skylib rules to simplify things. Reworks version header generation to use the Bazel module version rather than parsing CMake. * Update boot_stage2 Bazel build file Moves `includes` to be enumerated on the correct library. * Add WORKSPACE version fallback WORKSPACE Bazel projects don't support querying module version, so add a fallback of '0.0.1-WORKSPACE' so the build can succeed. * Fix malloc handling in Bazel build * Fix Bazel dependency cycle in pico_malloc * Prevent malloc from being linked into boot_stage2 Prevents Bazel from ever trying to link malloc into the boot_stage2 binary. * Remove custom bootloader platform A dedicated boot_stage2 platform introduces a lot of complexity that needs to be more thought-through.
This is a basic set of replacement library implementations sufficient to get simple applications
running on your computer (Raspberry Pi OS, Linux, macOS or Windows using Cygwin or Windows Subsystem for Linux).
It is selected by PICO_PLATFORM=host
in your CMake build
This can be extremely useful for testing and debugging higher level application code, or porting code which is not yet small enough to run on the RP2040 device itself.
This base level host library provides a minimal environment to compile programs, but is likely sufficient for programs that don't access hardware directly.
It is possible however to inject additional SDK library implementations/simulations to provide more complete functionality. For an example of this see the pico-host-sdl which uses the SDL2 library to add additional library support for pico_multicore, timers/alarms in pico-time and pico-audio/pico-scanvideo from pico-extras