Picolibc 1.8.5 #62882
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Picolibc 1.8.5 #62882
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The following west manifest projects have been modified in this Pull Request:
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This should address issue #62444 |
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I had a short chat with Anas about this. It's inevitably post 3.5 stuff. |
That's what I expected. No good reason to make this large a change with only a few days to go. |
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I'm seeing the same failure on main. This test is built with the external C library by default, so I'm not sure what updating picolibc would do anyways... |
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This was referenced Oct 24, 2023
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The compiler cannot tell that path_list_size is never used without being set, so help it out by providing a reasonable initialization value. Signed-off-by: Keith Packard <[email protected]>
CBPRINTF_FULL_INTEGRAL doesn't happen to explicitly conflict with CBPRINTF_NANO, but when CBPRINTF_NANO is enabled, there's no long long I/O support provided. Allow picolibc long-long I/O support to also be elided when CBPRINTF_NANO is enabled to save similar amounts of space. Signed-off-by: Keith Packard <[email protected]>
Picolibc version 1.8.5 offers additional memory savings and new long-long and minimal printf variants which can be selected from either the SDK or module version of the library. This needed a patch to the Zephyr cmake support bits to enable one of the new picolibc 1.8.5 features. Signed-off-by: Keith Packard <[email protected]>
This option in picolibc switches the assert macro between a chatty version and one which provides no information at all. This latter mode avoids placing the associated strings in memory. The Zephyr option is PICOLIBC_ASSERT_VERBOSE and it is disable by default. Signed-off-by: Keith Packard <[email protected]>
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With SDK 0.16.4 released, this should be ready to merge. I've rebased to re-test against current bits. |
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Picolibc's 'minimal' printf mode reduces functionality and size even more than the 'integer' mode. Use this where memory is at a premium and where the application knows that it does not require exact printf semantics. 1.8.5 adds two more printf variants, 'long long' and 'minimal'. The 'long long' variant is the same as the 'integer' variant but with long long support enabled. The 'minimal' variant reduces functionality and size even more than the 'integer' mode. Applications can use this where memory is at a premium and where the application does not require exact printf semantics. With these two added variants, the SDK has enough options so that all of the cbprintf modes can be supported with the pre-compiled bits: 1. CBPRINTF_NANO - picolibc's 'minimal' variant 2. CBPRINTF_REDUCED_INTEGRAL - picolibc's 'integer' variant 3. CBPRINTF_FULL_INTEGRAL - picolibc's 'long long' variant 4. CBPRINTF_FB_SUPPORT - picolibc's 'double' variant This patch makes the cbprintf Kconfig values drive the default picolibc variant, disables picolibc variants not capable of supporting the required cbprintf level, but allows applications to select more functionality in picolibc than cbprintf requires. Note that this depends on the SDK including picolibc 1.8.5. Without that, selecting the 'minimal' or 'long long' variant in Zephyr will end up with the default variant from picolibc, which is the full version with floating point support. When using the module things will work as specified. Signed-off-by: Keith Packard <[email protected]>
In minimal mode, format modifiers are not supported, leading to a lack of width and precision support. long long values are presented correctly in either long long or floating mode. Signed-off-by: Keith Packard <[email protected]>
When linking with the 0.16.3 SDK version of picolibc, using long long cbprintf support pulls in the full floating point printf which is much larger than the integer-only version. This ends up overflowing the memory region available for it. Increase the size of that by bumping the start of the fake region by 8kB. Signed-off-by: Keith Packard <[email protected]>
Picolibc 1.8.5 includes more control over printf capabilities, document those in the migration guide. Signed-off-by: Keith Packard <[email protected]>
cfriedt
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jhedberg
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This seems to have broken |
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Merge in picolibc version 1.8.5.
There is a matching SDK PR pending, zephyrproject-rtos/sdk-ng#707
This offers two new printf variants, 'long long', which provides an integer-only mode with long long support included and a 'minimal' variant which cuts out a bunch of format modifier support to make things very small.
hello-world on cortex-m3 FLASH sizes:
For comparison, here are the minimal C lib sizes:
With this change, all of the cbprintf configuration modes are reflected in the available printf variants, which means the SDK will be able to offer memory savings comparable to the picolibc module.
Closes: #62444
Closes: #64333