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[libc] Removed unused flags from baremetal cache files #168942

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Merged
merged 1 commit into from
Nov 20, 2025
Merged

[libc] Removed unused flags from baremetal cache files #168942

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2 changes: 1 addition & 1 deletion libc/cmake/caches/armv6m-none-eabi.cmake
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Original file line number Diff line number Diff line change
Expand Up @@ -2,7 +2,7 @@ set(CMAKE_SYSTEM_PROCESSOR arm CACHE STRING "")
set(RUNTIMES_TARGET_TRIPLE "armv6m-none-eabi" CACHE STRING "")

foreach(lang C;CXX;ASM)
set(CMAKE_${lang}_FLAGS "-march=armv6m -mcpu=cortex-m0plus -mfloat-abi=soft -Wno-atomic-alignment \"-Dvfprintf(stream, format, vlist)=vprintf(format, vlist)\" \"-Dfprintf(stream, format, ...)=printf(format)\" \"-Dfputs(string, stream)=puts(string)\" -D_LIBCPP_PRINT=1" CACHE STRING "")
set(CMAKE_${lang}_FLAGS "-march=armv6m -mcpu=cortex-m0plus -mfloat-abi=soft -Wno-atomic-alignment" CACHE STRING "")
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@boomanaiden154 boomanaiden154 Nov 20, 2025

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Bikeshedding a bit, but why do we need -Wno-atomic-alignment?

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@petrhosek petrhosek Nov 20, 2025

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That's because we use atomics for some internal API and there's no support unaligned accesses on Cortex-M0, but it's not a problem in practice because we don't do any unaligned accesses. We expect this will eventually get resolved by switching to TLS but we haven't had time to implement it yet.

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@boomanaiden154 boomanaiden154 Nov 20, 2025

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It seems like clang shouldn't emit this warning for targets that don't support unaligned atomic accesses?

Not sure about the implementation (ie whether warnings can be target specific, how we would plumb information about the target, etc).

endforeach()

include(${CMAKE_CURRENT_LIST_DIR}/baremetal_common.cmake)
2 changes: 1 addition & 1 deletion libc/cmake/caches/armv7em-none-eabi.cmake
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Original file line number Diff line number Diff line change
Expand Up @@ -2,7 +2,7 @@ set(CMAKE_SYSTEM_PROCESSOR arm CACHE STRING "")
set(RUNTIMES_TARGET_TRIPLE "armv7em-none-eabi" CACHE STRING "")

foreach(lang C;CXX;ASM)
set(CMAKE_${lang}_FLAGS "-march=armv7em -mcpu=cortex-m4 -mfloat-abi=soft -Wno-atomic-alignment \"-Dvfprintf(stream, format, vlist)=vprintf(format, vlist)\" \"-Dfprintf(stream, format, ...)=printf(format)\" \"-Dfputs(string, stream)=puts(string)\" -D_LIBCPP_PRINT=1" CACHE STRING "")
set(CMAKE_${lang}_FLAGS "-march=armv7em -mcpu=cortex-m4 -mfloat-abi=soft -Wno-atomic-alignment" CACHE STRING "")
endforeach()

include(${CMAKE_CURRENT_LIST_DIR}/baremetal_common.cmake)
2 changes: 1 addition & 1 deletion libc/cmake/caches/armv7m-none-eabi.cmake
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Original file line number Diff line number Diff line change
Expand Up @@ -2,7 +2,7 @@ set(CMAKE_SYSTEM_PROCESSOR arm CACHE STRING "")
set(RUNTIMES_TARGET_TRIPLE "armv7m-none-eabi" CACHE STRING "")

foreach(lang C;CXX;ASM)
set(CMAKE_${lang}_FLAGS "-march=armv7m -mcpu=cortex-m4 -mfloat-abi=soft -Wno-atomic-alignment \"-Dvfprintf(stream, format, vlist)=vprintf(format, vlist)\" \"-Dfprintf(stream, format, ...)=printf(format)\" \"-Dfputs(string, stream)=puts(string)\" -D_LIBCPP_PRINT=1" CACHE STRING "")
set(CMAKE_${lang}_FLAGS "-march=armv7m -mcpu=cortex-m4 -mfloat-abi=soft -Wno-atomic-alignment" CACHE STRING "")
endforeach()

include(${CMAKE_CURRENT_LIST_DIR}/baremetal_common.cmake)
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