On Fri, 8 Apr 2022 13:34:03 GMT, Magnus Ihse Bursie <i...@openjdk.org> wrote:
>> make/autoconf/flags-cflags.m4 line 116: >> >>> 114: fi >>> 115: >>> 116: CFLAGS_DEBUG_SYMBOLS="-g -gdwarf-4" >> >> We may need to guard this with a FLAGS_COMPILER_CHECK_ARGUMENTS. Perhaps it >> should also be applied only on Linux since the whole feature is Linux only. >> What do you think @magicus? > > I'm googling around for some information about -gdwarf-4 but is mostly coming > up empty handed. :( I found > [this](https://www.phoronix.com/scan.php?page=news_item&px=GCC-11-DWARF-5-Possible-Default) > saying that dwarf-5 became default in gcc11. It also claims dwarf-4 is about > 10 years old. My guess is that all our supported gcc versions do support > -gdwarf-4, but this needs to be verified. > > In practice, we only use gcc on linux so I'm not convinced we need to have an > addition check for that. If we ever are going to support gcc on other OSes I > think we'll have many more, much harder problems, than to remove the > -gdwarf-4 flag. I'm back to work again. I also had a look but could not find something on Google, either. I then skimmed through the old GCC manuals. I found the first occurrence of `-gdwarf-4` in the manual for GCC 4.5.4 [here](https://gcc.gnu.org/onlinedocs/gcc-4.5.4/gcc.pdf): - gdwarf-version Produce debugging information in DWARF format (if that is supported). This is the format used by DBX on IRIX 6. The value of version may be either 2, 3 or 4; the default version is 2. While the manual for GCC 4.4.7 only mentions `-gdwarf-2`: -gdwarf-2 Produce debugging information in DWARF version 2 format (if that is supported). This is the format used by DBX on IRIX 6. With this option, GCC uses features of DWARF version 3 when they are useful; version 3 is upward compatible with version 2, but may still cause problems for older debuggers. The minimum accepted GCC version is currently 5.0 according to: https://github.com/openjdk/jdk/blob/d5ae3833b1b71eb84fadb69c0c92851400f8921c/doc/building.md?plain=1#L341-L344 This suggests that all our supported GCC versions should accept `-gdwarf-4`. ------------- PR: https://git.openjdk.java.net/jdk/pull/7126
