https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77497
Bug ID: 77497
Summary: Setting DWARF level and debug level together has
flag-ordering-dependent results
Product: gcc
Version: 6.1.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: driver
Assignee: unassigned at gcc dot gnu.org
Reporter: torne at google dot com
Target Milestone: ---
The -gdwarf-N option appears to confuse a previously set -gN debug level, and
the intended interpretation of the options only applies if you set the DWARF
level first. I compiled the same trivial source file with all combinations of
-g[123] and -gdwarf-[34] in both parameter orders and the file sizes show the
problem pretty clearly:
-rw-r----- 1 torne eng 2412 Sep 5 18:04 test-g1-gdwarf-3.o
-rw-r----- 1 torne eng 2384 Sep 5 18:04 test-g1-gdwarf-4.o
-rw-r----- 1 torne eng 2412 Sep 5 18:04 test-g2-gdwarf-3.o
-rw-r----- 1 torne eng 2384 Sep 5 18:04 test-g2-gdwarf-4.o
-rw-r----- 1 torne eng 16648 Sep 5 18:04 test-g3-gdwarf-3.o
-rw-r----- 1 torne eng 16620 Sep 5 18:04 test-g3-gdwarf-4.o
-rw-r----- 1 torne eng 2268 Sep 5 18:04 test-gdwarf-3-g1.o
-rw-r----- 1 torne eng 2412 Sep 5 18:04 test-gdwarf-3-g2.o
-rw-r----- 1 torne eng 16648 Sep 5 18:04 test-gdwarf-3-g3.o
-rw-r----- 1 torne eng 2248 Sep 5 18:04 test-gdwarf-4-g1.o
-rw-r----- 1 torne eng 2384 Sep 5 18:04 test-gdwarf-4-g2.o
-rw-r----- 1 torne eng 16620 Sep 5 18:04 test-gdwarf-4-g3.o
In the cases where -g1 appears before the DWARF level it appears to be ignored
and the exact same output as -g2 is generated. Weirdly this *doesn't* happen
for -g3?
This appears to have been introduced in gcc 4.9 (I can't repro in 4.8) and is
still happening in 6.1.1. The docs don't appear to state that these flags are
ordering-dependent, and in any case it's somewhat weird (especially that it
doesn't affect -g3, only -g1).
