Update Clang toolchain used by Bazel #2879
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gh-raspberrypi/pico-sdk!2879
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Delete branch "update_toolchain_mar20"
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The Clang toolchain is updated to a newer revision 9431920bfaee50f4b1552fc01ea081a5c18a5a3b from March 20, 2026.
Fixes #2859
Please do not submit against
master, usedevelopinsteadCC: @petrhosek @kilograham
@ -11,2 +8,3 @@set(PICO_CLANG_RUNTIMES armv8m.main_hard_fp armv8m.main_hard_fp_unaligned armv8m.main_hard_fp_unaligned_size)# these are all the directories under LLVM embedded toolchain for ARM (newlib or pibolibc)set(PICO_CLANG_RUNTIMES armv8m.main_hard_fp armv8m.main_hard_fp_unaligned)else()Was this just a "testing print", which now ought to be removed?
This changes the default
PICO_HARD_FLOAT_ABIfor all Clang users, which I don't think is necessary for this PR - all the other Clang toolchains still support both hard and soft float ABIs, it's just the new Google toolchain that only supports hard float.A better fix might be to remove
armv8m.main-unknown-none-eabifrom the softfpPICO_CLANG_RUNTIMESlist, which should then throw theCould not find an llvm runtimeerror ifPICO_HARD_FLOAT_ABI=0(assuming support for the older soft float toolchain is not required).@ -11,2 +8,3 @@set(PICO_CLANG_RUNTIMES armv8m.main_hard_fp armv8m.main_hard_fp_unaligned armv8m.main_hard_fp_unaligned_size)# these are all the directories under LLVM embedded toolchain for ARM (newlib or pibolibc)set(PICO_CLANG_RUNTIMES armv8m.main_hard_fp armv8m.main_hard_fp_unaligned)else()yes. I'll drop the message.
Done. PTAL
@ -11,2 +8,3 @@set(PICO_CLANG_RUNTIMES armv8m.main_hard_fp armv8m.main_hard_fp_unaligned armv8m.main_hard_fp_unaligned_size)# these are all the directories under LLVM embedded toolchain for ARM (newlib or pibolibc)set(PICO_CLANG_RUNTIMES armv8m.main_hard_fp armv8m.main_hard_fp_unaligned)else()Done. PTAL
@ -9,3 +7,2 @@# todo - doesn't seem to be a hard_fp variant for google atm?# these are all the directories under LLVM embedded toolchain for ARM (newlib or picolibc)set(PICO_CLANG_RUNTIMES armv8m.main_hard_fp armv8m.main_hard_fp_unaligned armv8m.main_hard_fp_unaligned_size)# these are all the directories under LLVM embedded toolchain for ARM (newlib or pibolibc)@ -9,3 +7,2 @@# todo - doesn't seem to be a hard_fp variant for google atm?# these are all the directories under LLVM embedded toolchain for ARM (newlib or picolibc)set(PICO_CLANG_RUNTIMES armv8m.main_hard_fp armv8m.main_hard_fp_unaligned armv8m.main_hard_fp_unaligned_size)# these are all the directories under LLVM embedded toolchain for ARM (newlib or pibolibc)I'm going to revert this line, so you can build both hard-fp or soft-fp with google llvm (which means any compiler version is suppoed as long as you pass the right hard/soft float)
This is the best option i can see given the issues with google-llvm not indicating in any way that it has changed ABI
@ -9,3 +7,2 @@# todo - doesn't seem to be a hard_fp variant for google atm?# these are all the directories under LLVM embedded toolchain for ARM (newlib or picolibc)set(PICO_CLANG_RUNTIMES armv8m.main_hard_fp armv8m.main_hard_fp_unaligned armv8m.main_hard_fp_unaligned_size)# these are all the directories under LLVM embedded toolchain for ARM (newlib or pibolibc)As discussed offline, we are bumping the toolchain revision to a new enough revision but prior to toolchain switching the float ABI for cortex-m33 runtime libraries to hard float.