On Mon, Nov 02, 2020 at 11:20:41AM +0900, Masahiro Yamada wrote: > > --- /dev/null > > +++ b/scripts/test_dwarf5_support.sh > > @@ -0,0 +1,4 @@ > > +#!/bin/sh > > +# SPDX-License-Identifier: GPL-2.0 > > +set -eu > > +echo ".file 0 \"asdf\"" | $* -Wa,-gdwarf-5 -c -x assembler -o /dev/null - > > > > Please tell me how this script detects the dwarf-5 capability. > > > This script fails for GCC 10. One thing is GCC DWARF-5 support, that is whether the compiler will support -gdwarf-5 flag, and that support should be there from GCC 7 onwards. Another separate thing is whether the assembler does support the -gdwarf-5 option (i.e. if you can compile assembler files with -Wa,-gdwarf-5) for GNU as I think that is binutils 35.1, i.e. very new); but only if you want to pass the -Wa,-gdwarf-5 only when compiling *.s and *.S files. That option is about whether the assembler will emit DWARF5 or DWARF2 .debug_line. It is fine to compile C sources with -gdwarf-5 and use DWARF2 .debug_line for assembler files if as doesn't support it. Yet another thing is if you can pass -Wa,-gdwarf-5 even when compiling C files. There are several bugs in that category that have been fixed only in the last few days on binutils trunk, I'd suggest just not to bother, GCC 11 will have proper test for fixed assembler and will pass -gdwarf-5 to as when compiling even C sources with -gdwarf-5. The reason is to get DWARF5 .debug_line (.debug_line is usually produced by the assembler, not compiler, from .file/.loc directives). Jakub
