Move some constant arrays from data to text section #9187
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_default_tunes was marked as 'const char *' array, which means the data of the array was not actually const and thus landed in the data section (so in RAM instead of FLASH). The size of the array is 64 bytes.
_uorb_topics_list was marked as 'const char *' array, which means the data of the array was not actually const and thus landed in the data section (so in RAM instead of FLASH). The size of the array is 436 bytes.
LorenzMeier
approved these changes
Mar 29, 2018
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@bkueng Awesome, thank you very much. How did you find it? :) |
potaito
reviewed
Mar 29, 2018
| @@ -56,7 +56,7 @@ msgs_count_all = len(msg_names_all) | |||
| @[end for] | |||
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| const size_t _uorb_topics_count = @(msgs_count_all); | |||
| const struct orb_metadata* _uorb_topics_list[_uorb_topics_count] = { | |||
| const constexpr struct orb_metadata* const _uorb_topics_list[_uorb_topics_count] = { | |||
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Wouldn't constexpr alone instead of const constexpr suffice?
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In this case yes. But more is more :D
I was looking at what needs how much space in the different ELF sections. For example you can look at the largest consumers in the data section with: |
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Thanks, I did not know that |
dagar
approved these changes
Mar 29, 2018
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2 Arrays with constant data in uORB and the tunes library were marked as 'const T *' array, which means the data of the array was not actually const and thus landed in the data section (so in RAM instead of FLASH).
Reduces RAM usage by ~500 bytes.
@potaito fyi