On 6/27/2020 7:23 AM, Jeffrey Walton via Gcc-help wrote:
Hi Everyone,
I'm trying to debug a c function that is mostly a massive collection
of macros.
I changed the makefile recipe to preprocess the source trying to
produce something I can step:
#blake2b: blake2b.c
# $(CC) blake2b.c -o $@ $(CFLAGS) $(POWER8_CFLAG) -DBLAKE2B_SELFTEST
blake2b: blake2b.c
$(CC) -E blake2b.c -o blake2b.E $(CFLAGS) $(POWER8_CFLAG)
-DBLAKE2B_SELFTEST
$(CC) -x c blake2b.E -o $@ $(CFLAGS) $(POWER8_CFLAG) -DBLAKE2B_SELFTEST
But GDB is not stepping it:
238 ROUND( 0 );
(gdb) s
239 ROUND( 1 );
(gdb) s
240 ROUND( 2 );
(gdb) q
I also switched to -save-temps with the same result - no stepping.
blake2b: blake2b.c
$(CC) -E blake2b.c -o blake2b.i $(CFLAGS) -save-temps
$(POWER8_CFLAG) -DBLAKE2B_SELFTEST
$(CC) blake2b.i -o $@ $(CFLAGS) $(POWER8_CFLAG) -DBLAKE2B_SELFTEST
Is there a way to achieve this using GCC without changing the source
files?
Thanks in advance.
You can do step by step expansion of a macro using the Wave tool from
the Wave library in Boost. It is excellent and works as a C++ standard
compliant preprocessor. I have also found gcc's preprocessor to also be
excellent and completely C++ standards compliant, so I would not be
surprised if the step by step expansion if a macro using the Wave tool
mimicked exactly the same step by step expansion of a macro in the gcc
preprocessor.
