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This cache file demonstrates how to build a complete baremetal Clang/LLVM toolchain that can be used to build the Pico SDK.

This cache file demonstrates how to build a complete baremetal
Clang/LLVM toolchain that can be used to build the Pico SDK.
@petrhosek petrhosek marked this pull request as ready for review November 12, 2025 20:20
@llvmbot llvmbot added the clang Clang issues not falling into any other category label Nov 12, 2025
@petrhosek petrhosek force-pushed the clang-cmake-cache-pico branch from a374083 to 30c833e Compare November 12, 2025 20:20
@petrhosek petrhosek requested a review from Prabhuk November 12, 2025 20:20
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llvmbot commented Nov 12, 2025

@llvm/pr-subscribers-clang

Author: Petr Hosek (petrhosek)

Changes

This cache file demonstrates how to build a complete baremetal Clang/LLVM toolchain that can be used to build the Pico SDK.


Full diff: https://github.com/llvm/llvm-project/pull/113267.diff

1 Files Affected:

  • (added) clang/cmake/caches/Pico.cmake (+88)
diff --git a/clang/cmake/caches/Pico.cmake b/clang/cmake/caches/Pico.cmake
new file mode 100644
index 0000000000000..11beb9c8c6bd4
--- /dev/null
+++ b/clang/cmake/caches/Pico.cmake
@@ -0,0 +1,88 @@
+# This file sets up a CMakeCache for the Pico SDK toolchain build.
+
+set(CMAKE_BUILD_TYPE Release CACHE STRING "")
+
+set(LLVM_TARGETS_TO_BUILD ARM;RISCV CACHE STRING "")
+set(LLVM_ENABLE_PROJECTS clang;lld;llvm CACHE STRING "")
+set(LLVM_ENABLE_RUNTIMES compiler-rt;libcxx;libc CACHE STRING "")
+
+set(CLANG_DEFAULT_CXX_STDLIB libc++ CACHE STRING "")
+set(CLANG_DEFAULT_LINKER lld CACHE STRING "")
+set(CLANG_DEFAULT_RTLIB compiler-rt CACHE STRING "")
+set(CLANG_DEFAULT_UNWINDLIB libunwind CACHE STRING "")
+
+set(LLVM_INSTALL_TOOLCHAIN_ONLY ON CACHE BOOL "")
+set(LLVM_TOOLCHAIN_TOOLS
+  llvm-ar
+  llvm-cov
+  llvm-objcopy
+  llvm-objdump
+  llvm-profdata
+  llvm-ranlib
+  llvm-readelf
+  llvm-readobj
+  llvm-size
+  llvm-strings
+  llvm-strip
+  llvm-symbolizer
+  CACHE STRING "")
+set(LLVM_DISTRIBUTION_COMPONENTS
+  builtins
+  clang
+  clang-resource-headers
+  lld
+  runtimes
+  ${LLVM_TOOLCHAIN_TOOLS}
+  CACHE STRING "")
+
+set(LLVM_BUILTIN_TARGETS armv6m-none-eabi;armv8m.main-none-eabi;riscv32-unknown-elf CACHE STRING "")
+foreach(target ${LLVM_BUILTIN_TARGETS})
+  set(BUILTINS_${target}_CMAKE_SYSTEM_NAME Generic CACHE STRING "")
+  set(BUILTINS_${target}_CMAKE_BUILD_TYPE MinSizeRel CACHE STRING "")
+  set(BUILTINS_${target}_COMPILER_RT_BAREMETAL_BUILD ON CACHE BOOL "")
+endforeach()
+
+set(BUILTINS_armv6m-none-eabi_CMAKE_SYSTEM_PROCESSOR arm CACHE STRING "")
+set(BUILTINS_armv8m.main-none-eabi_CMAKE_SYSTEM_PROCESSOR arm CACHE STRING "")
+set(BUILTINS_riscv32-unknown-elf_CMAKE_SYSTEM_PROCESSOR RISCV CACHE STRING "")
+foreach(lang C;CXX;ASM)
+  set(BUILTINS_armv6m-none-eabi_CMAKE_${lang}_FLAGS "-march=armv6m -mcpu=cortex-m0plus -mfloat-abi=soft" CACHE STRING "")
+  set(BUILTINS_armv8m.main-none-eabi_CMAKE_${lang}_FLAGS "-march=armv8m.main+fp+dsp -mcpu=cortex-m33 -mfloat-abi=softfp" CACHE STRING "")
+  set(BUILTINS_riscv32-unknown-elf_CMAKE_${lang}_FLAGS "-march=rv32imac_zicsr_zifencei_zba_zbb_zbs_zbkb -mabi=ilp32" CACHE STRING "")
+endforeach()
+
+set(LLVM_RUNTIME_TARGETS armv6m-none-eabi;armv8m.main-none-eabi;riscv32-unknown-elf CACHE STRING "")
+foreach(target ${LLVM_RUNTIME_TARGETS})
+  set(RUNTIMES_${target}_CMAKE_SYSTEM_NAME Generic CACHE STRING "")
+  set(RUNTIMES_${target}_CMAKE_BUILD_TYPE MinSizeRel CACHE STRING "")
+  set(RUNTIMES_${target}_CMAKE_TRY_COMPILE_TARGET_TYPE STATIC_LIBRARY CACHE STRING "")
+  set(RUNTIMES_${target}_LLVM_ENABLE_RUNTIMES libc;libcxx CACHE STRING "")
+  set(RUNTIMES_${target}_LLVM_ENABLE_ASSERTIONS OFF CACHE BOOL "")
+  set(RUNTIMES_${target}_LLVM_INCLUDE_TESTS OFF CACHE BOOL "")
+  set(RUNTIMES_${target}_LLVM_LIBC_FULL_BUILD ON CACHE BOOL "")
+  set(RUNTIMES_${target}_LIBC_ENABLE_USE_BY_CLANG ON CACHE BOOL "")
+  set(RUNTIMES_${target}_LIBCXX_CXX_ABI none CACHE STRING "")
+  set(RUNTIMES_${target}_LIBCXX_ENABLE_SHARED OFF CACHE BOOL "")
+  set(RUNTIMES_${target}_LIBCXX_ENABLE_FILESYSTEM OFF CACHE BOOL "")
+  set(RUNTIMES_${target}_LIBCXX_ENABLE_RANDOM_DEVICE OFF CACHE BOOL "")
+  set(RUNTIMES_${target}_LIBCXX_ENABLE_LOCALIZATION OFF CACHE BOOL "")
+  set(RUNTIMES_${target}_LIBCXX_ENABLE_UNICODE OFF CACHE BOOL "")
+  set(RUNTIMES_${target}_LIBCXX_ENABLE_WIDE_CHARACTERS OFF CACHE BOOL "")
+  set(RUNTIMES_${target}_LIBCXX_ENABLE_EXCEPTIONS OFF CACHE BOOL "")
+  set(RUNTIMES_${target}_LIBCXX_ENABLE_RTTI OFF CACHE BOOL "")
+  set(RUNTIMES_${target}_LIBCXX_ENABLE_THREADS OFF CACHE BOOL "")
+  set(RUNTIMES_${target}_LIBCXX_ENABLE_MONOTONIC_CLOCK OFF CACHE BOOL "")
+  set(RUNTIMES_${target}_LIBCXX_SHARED_OUTPUT_NAME "c++-shared" CACHE STRING "")
+  set(RUNTIMES_${target}_LIBCXX_USE_COMPILER_RT ON CACHE BOOL "")
+  set(RUNTIMES_${target}_RUNTIMES_USE_LIBC llvm-libc CACHE STRING "")
+endforeach()
+
+set(RUNTIMES_armv6m-none-eabi_CMAKE_SYSTEM_PROCESSOR arm CACHE STRING "")
+set(RUNTIMES_armv8m.main-none-eabi_CMAKE_SYSTEM_PROCESSOR arm CACHE STRING "")
+set(RUNTIMES_riscv32-unknown-elf_CMAKE_SYSTEM_PROCESSOR RISCV CACHE STRING "")
+foreach(lang C;CXX;ASM)
+  # TODO: Use internal logging API instead of fprintf in libc++
+  set(RUNTIMES_armv6m-none-eabi_CMAKE_${lang}_FLAGS "-march=armv6m -mcpu=cortex-m0plus -mfloat-abi=soft -Wno-atomic-alignment \"-Dvfprintf(stream, format, vlist)=vprintf(format, vlist)\" \"-Dfprintf(stream, format, ...)=printf(format)\" \"-Dfputs(string, stream)=puts(string)\" -D_LIBCPP_PRINT=1" CACHE STRING "")
+  set(RUNTIMES_armv8m.main-none-eabi_CMAKE_${lang}_FLAGS "-march=armv8m.main+fp+dsp -mcpu=cortex-m33 -mfloat-abi=softfp -Wno-atomic-alignment \"-Dvfprintf(stream, format, vlist)=vprintf(format, vlist)\" \"-Dfprintf(stream, format, ...)=printf(format)\" \"-Dfputs(string, stream)=puts(string)\" -D_LIBCPP_PRINT=1" CACHE STRING "")
+  set(RUNTIMES_riscv32-unknown-elf_CMAKE_${lang}_FLAGS "-march=rv32imac_zicsr_zifencei_zba_zbb_zbs_zbkb -mabi=ilp32 -Wno-atomic-alignment \"-Dvfprintf(stream, format, vlist)=vprintf(format, vlist)\" \"-Dfprintf(stream, format, ...)=printf(format)\" \"-Dfputs(string, stream)=puts(string)\" -D_LIBCPP_PRINT=1" CACHE STRING "")
+endforeach()

set(RUNTIMES_armv8m.main-none-eabi_CMAKE_SYSTEM_PROCESSOR arm CACHE STRING "")
set(RUNTIMES_riscv32-unknown-elf_CMAKE_SYSTEM_PROCESSOR RISCV CACHE STRING "")
foreach(lang C;CXX;ASM)
# TODO: Use internal logging API instead of fprintf in libc++
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What does "internal" here mean?

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