Update GNU Makefiles to generate DEBUG binaries

[oliviermartin]

• '-g' has been added for all the build to produce debugging information. '-g' allows to get the symbols when debugging with GDB.
• introduce the macro 'DEBUG' to enable/disable build optimization.

Limitations:

• Support in non-Makefile projects has been added.

[bogdanm]

Hi,

Thanks for your contribution. The idea is good, but it needs a bit more work. What it does right now is simply remove the current optimization option (-Os) and add the debug flag instead (-g). This can easily introduce backward compatibility issues. The right way to do this is to add a new option to the export scripts (see for example '-o' in get_default_option_parser() from workspace_tools/options.py and the way that's used in various places). Also, you're using -g3 for disco_f407vg, but just -g for the rest of the targets. Is there a particular reason for this?

Thanks,
Bogdan

[oliviermartin]

• To answer the question about gcc_arm_disco_f407vg.tmpl .
  '-g3' was already present in the Makefile for this platform. I am only move it from the end of the line to the beginning of the line to match the other Makefile

-CC_FLAGS = $(CPU) -c -Os -fno-common -fmessage-length=0 -Wall -fno-exceptions -ffunction-sections -fdata-sections -g3
+CC_FLAGS = $(CPU) -c -g3 -fno-common -fmessage-length=0 -Wall -fno-exceptions -ffunction-sections -fdata-sections

• Thanks for pointing me to workspace_tools/options.py. Actually '-g' is already supported, workspace_tools/toolchains/gcc.py:

          if "debug-info" in self.options:
          common_flags.append("-g")

The point of this patch is to easily be able to debug binaries with CMSIS-DAP. Without '-g' you would not see the symbols in GDB.
Currently, there is no way to enable this 'workspace_tools' option when users export their project from the online compiler to their offline GCC project. They need to hack their Makefile to get it working.

With my change, the '-Os' is still the default optimization. By default DEBUG is not be set, so the build flags fall back on 'CC_FLAGS += -DNDEBUG -Os'.
The way to turn off optimization (-O0) is to build with make DEBUG=1.

This change would also help implementing this feature: https://mbed.org/forum/bugs-suggestions/topic/4356/

[bogdanm]

My bad, I've completely missed the the 'ifeq' part of your patches. Yes, that's perfect.
One last thing before I merge this: have you signed https://mbed.org/contributor_agreement/ ? It's a required step for all mbed contributors.

Thanks,
Bogdan

[oliviermartin]

No problem ;-)

Yes I have signed the contributor agreement: "You accepted the Contributor Agreement on Tue 18 Feb 2014."

[bogdanm]

Thanks!