Debug info with C macros (-g3) not honoured in LTO builds

"R. Diez via gcc-help" <gcc-help@xxxxxxxxxxx> · Thu, 13 Feb 2020 16:48:29 +0100

Hi all:

I am using a self-built GCC 8.3.0 cross-compiler for ARM Cortex-M4F on Ubuntu 18.04.4 LTS.

I have several Autoconf projects that generate debug builds, release builds and release builds with LTO.

I have turned debug information on with level 3 with -g3. The expectation is that C preprocessor macros (#define symbols) get included in 
the debug information.

I can test it within GDB with commands "print MY_MACRO" and "info macro MY_MACRO".

The trouble is, as soon as I build with LTO, the preprocessor macros do not get included in the debug information. Other debug information 
works fine. It feels like -g2 is in place, instead of -g3 .

I am passing the same flags when linking as when compiling. The only change I make is adding "-flto" to the CFLAGS and CXXFLAGS. Other than 
that, LTO builds seem to be fine.

Is this kind of problem with -g3 and LTO already known? I couldn't find anything on this.

Thanks in advance,
  rdiez