ESP8266 Community Forum

- Mon Apr 01, 2019 5:18 pm #81494 Thanks for the tips! I'll have a look through your settings and roll some of them into my own.

One thing you mentioned -

also you must use fat-lto-object or otherwise esptool(2) can't handle the resulting object file.

- I have never used this setting and have never had a problem with either esptool version. Maybe you need it because of one of the other linker settings? Maybe it's the

-fuse-linker-plugin

setting?

Also while looking at the effect of no-check-sections I came across options to demangle names. I'll have a try with those to see if they help when lto is on.

- Mon Apr 01, 2019 10:43 pm #81501 Just tried your warnings and got some errors due to unrecognised options - I'm using gcc 6.4.0 so I reckon you're using 7.x? These are the ones that 6.4.0 will complain about:

Code: Select allxtensa-lx106-elf-gcc: error: unrecognized command line option '-Wformat-overflow=2'; did you mean '-Wstrict-overflow='?
xtensa-lx106-elf-gcc: error: unrecognized command line option '-Wimplicit-fallthrough=5'; did you mean '-Wno-fallthrough'?
xtensa-lx106-elf-gcc: error: unrecognized command line option '-Wformat-truncation=2'; did you mean '-Wline-truncation'?
xtensa-lx106-elf-gcc: error: unrecognized command line option '-Wstringop-overflow=4'; did you mean '-Wstrict-overflow='?
xtensa-lx106-elf-gcc: error: unrecognized command line option '-Walloca'; did you mean '-Wall'?
xtensa-lx106-elf-gcc: error: unrecognized command line option '-Wduplicated-branches'; did you mean '-Wduplicated-cond'?
xtensa-lx106-elf-gcc: error: unrecognized command line option '-Wdangling-else'


- Tue Apr 02, 2019 2:45 pm #81516 Yes I am now using a "7" version, that explains the wider variety in available warnings and also why I need the "fat" object flag, as gcc 7 by default generates "thin" objects.

- Fri Apr 12, 2019 3:27 am #81715 An now we even have gcc 8 available