Custom Arduino Build to save on code size?

[DedeHai]

@softhack007 we recently had a quick discussion in discord about reducing code size as there seem to be many options, described here:
https://docs.espressif.com/projects/esp-idf/en/stable/esp32/api-guides/performance/size.html

this is however using the Espressif IDF and not the arduino platform. There is the option to custom compile the arduino platform:
https://community.platformio.org/t/using-arduino-framework-point-to-custom-sdkconfig-h-file/12622/3
https://github.com/espressif/esp32-arduino-lib-builder

is this something you are aware of already?

[softhack007]

Hi @DedeHai,
I've seen your message - right now I'm busy with getting a new WLEDMM release ready. I'll come back to the topic afterwards.

Actually, I have no experience with using ESP-IDF 'kconfig' for creating a custom IDF component for arduino-esp32. Just I would be careful about this, because it's very easy to drop a component that might later be needed in some usermod.

About making "LTO" the default for compiling - i have played with it some time ago; it does help, however I see some potentially problematic areas:

• usermods use a lot of external libs (not under WLED control), and you'll never know if any of these is not working correctly with -flto.
• debugging and reading stack traces becomes impossible with LTO. Most developers don't know how to build a debug config (and debug firmware is too large any way for a standard 4MB partition), so there will be a lot of "wtf" if we just add -flto without a simple fallback solution.
• Additionally, when user "in the field" have crashes, we're sometimes lucky to get a stack dump. These stack traces will become useless when the firmware was build with -flto...