http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24985
Manuel López-Ibáñez <manu at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |dodji at gcc dot gnu.org --- Comment #26 from Manuel López-Ibáñez <manu at gcc dot gnu.org> 2012-04-07 12:53:34 UTC --- A sneak-peek into the future ;-) manuel@gcc12:~/test2/186200M/build/gcc$ ./cc1 -ftrack-macro-expansion ~/macro-clang.c foo /home/manuel/macro-clang.c: In function ‘foo’: /home/manuel/macro-clang.c:2:94: error: invalid operands to binary < (have ‘struct mystruct’ and ‘float’) #define MYMAX(A,B) __extension__ ({ __typeof__(A) __a = (A); __typeof__(B) __b = (B); __a < __b ? __b : __a; }) ^ /home/manuel/macro-clang.c:2:94: note: in expansion of macro 'MYMAX' #define MYMAX(A,B) __extension__ ({ __typeof__(A) __a = (A); __typeof__(B) __b = (B); __a < __b ? __b : __a; }) ^ /home/manuel/macro-clang.c:8:11: note: expanded from here float x = MYMAX(p, f); ^ This is not possible with the patch just posted, but I will send this follow up after the initial part is committed. Of course, it needs some fine-tuning to avoid repetitions, but this is a problem with the locations given by the macro expansion unwinder, which, in my opinion, doesn't give the best location for each message and already produces repetitions. See: /home/manuel/macro-caret.c: In function ‘g’: /home/manuel/macro-caret.c:5:14: error: invalid operands to binary << (have ‘double’ and ‘int’) OPERATE (A,<<,B) ^ /home/manuel/macro-caret.c:2:9: note: in expansion of macro 'OPERATE' OPRD1 OPRT OPRD2; ^ /home/manuel/macro-caret.c:5:3: note: expanded from here OPERATE (A,<<,B) ^ /home/manuel/macro-caret.c:5:14: note: in expansion of macro 'SHIFTL' OPERATE (A,<<,B) ^ /home/manuel/macro-caret.c:8:3: note: expanded from here SHIFTL (A,1) ^ /home/manuel/macro-caret.c:8:3: note: in expansion of macro 'MULT' SHIFTL (A,1) ^ /home/manuel/macro-caret.c:13:3: note: expanded from here MULT (1.0);// 1.0 << 1; <-- so this is an error. ^ Another possibility could be to print the preprocessed string when saying "in expansion". However, I am not sure how hard it will be to obtain the preprocessed string (or to re-create it at runtime). Help and pointers on how to achieve that are welcome. Dodji, are you planning to propose to enable -ftrack-macro-expansion by default in GCC 4.8?