pico-sdk: Switch to picolibc #12
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| target_link_options(${NAME} PRIVATE "-nostdlib") | ||
| elseif (PICO_C_COMPILER_IS_GNU) | ||
| target_link_options(${NAME} PRIVATE "--specs=nosys.specs") | ||
| target_compile_options(${NAME} PRIVATE "--specs=picolibc.specs") |
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Please add a history about this change to ChangeLog.zephyr.md.
This selects picolibc by using --specs=picolibc.specs for compiling and linking. The linker scripts are adjusted to add KEEP to ensure that --gc-sections doesn't remove the contents of the files. Signed-off-by: Keith Packard <[email protected]>
The boot loader can use picolibc even if the app needs newlib for some reason; we still get the picolibc benefits in the boot loader. |
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| target_link_libraries(${NAME} hardware_regs boot_stage2_headers) | ||
| target_link_options(${NAME} PRIVATE "LINKER:--script=${PICO_BOOT_STAGE2_DIR}/boot_stage2.ld") | ||
| target_link_options(${NAME} PRIVATE "-T${PICO_BOOT_STAGE2_DIR}/boot_stage2.ld") |
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It's a minor point, but I think long options are easier to read in scripts.
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picolibc's spec fragments only look for the -T version of this option, so we must use the short variant to prevent addition of the picolibc linker script here.
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OK, I got it.
Thank you for your clarification.
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Could you take a look, please? |
Can you expand on this? What's the benefit? I've read the commit message and it has the what, but not the why of this. |
Probably the most visible benefit is a reduction in memory usage -- picolibc has smaller implementations of many core parts of the C library (stdio, ctype, locales) as well as general memory saving architectural changes (eliminating struct reent). It's also routinely tested for the target systems. I'll be enabling these tests within the Zephyr SDK build to catch bugs introduced in any part of the system (binutils, compiler, linker, libraries). Newlib lacks any visible CI system. |
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Merged. Please update |
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This commit has not yet been reflected in west.yml, |
west.yml got this patch when it pulled in some other hal changes. |
I see. I didn't get a notification about that, so I missed it. Thank you. |
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This selects picolibc by using --specs=picolibc.specs for compiling and linking. The linker scripts are adjusted to add KEEP to ensure that --gc-sections doesn't remove the contents of the files.