On Wed, May 13, 2020 at 1:40 AM Fangrui Song via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> -fsplit-dwarf is similar to -gsplit-dwarf, but does not enable debugging
> information by itself. This makes it easier to be plugged into a build
> system without worrying that unnecessary debugging information may be
> generated.
Hmm. I think having both -fsplit-dwarf and -gsplit-dwarf is confusing. Doesn't
feeding -g0 -gsplit-dwarf into the build system work with a later -g then
enabling debug info generation?
Having said that my preference would be (in the following order):
1) make -gsplit-dwarf not imply -g
2) add -gsplit-dwarf0 implying -g0 (and maybe accept -gsplit-dwarf[012])
for 1) the ship may have sailed. For 2) it might be confused
with -gdwarf2 so maybe it should be -g0split-dwarf. Eh.
I still like 1) most.
Oh, and -gsplit-dwarf is largely unmaintained.
Did I mention I dislike -fsplit-dwarf? ;)
Richard.
> 2020-05-12 Fangrui Song <mask...@google.com>
>
> PR debug/95096
> * common.opt: Add -fsplit-dwarf.
> * doc/invoke.texi: Document it.
> ---
> gcc/common.opt | 4 ++++
> gcc/doc/invoke.texi | 8 ++++++++
> 2 files changed, 12 insertions(+)
>
> diff --git a/gcc/common.opt b/gcc/common.opt
> index 4464049fc1f..07aa9f28002 100644
> --- a/gcc/common.opt
> +++ b/gcc/common.opt
> @@ -2515,6 +2515,10 @@ fsingle-precision-constant
> Common Report Var(flag_single_precision_constant) Optimization
> Convert floating point constants to single precision constants.
>
> +fsplit-dwarf
> +Common Driver Var(dwarf_split_debug_info) Init(0)
> +If debug information is enabled, generate debug information in separate .dwo
> files.
> +
> fsplit-ivs-in-unroller
> Common Report Var(flag_split_ivs_in_unroller) Init(1) Optimization
> Split lifetimes of induction variables when loops are unrolled.
> diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
> index 850aeac033d..6590e60f5b3 100644
> --- a/gcc/doc/invoke.texi
> +++ b/gcc/doc/invoke.texi
> @@ -448,6 +448,7 @@ Objective-C and Objective-C++ Dialects}.
> -femit-struct-debug-detailed@r{[}=@var{spec-list}@r{]} @gol
> -fno-eliminate-unused-debug-symbols -femit-class-debug-always @gol
> -fno-merge-debug-strings -fno-dwarf2-cfi-asm @gol
> +-fsplit-dwarf @gol
> -fvar-tracking -fvar-tracking-assignments}
>
> @item Optimization Options
> @@ -8771,6 +8772,13 @@ also be used to change an absolute path to a relative
> path by using
> are location independent, but may require an extra command to tell GDB
> where to find the source files. See also @option{-ffile-prefix-map}.
>
> +@item -fsplit-dwarf
> +@opindex fsplit-dwarf
> +If DWARF debugging information is enabled, separate as much debugging
> +information as possible into a separate output file with the extension
> +@file{.dwo}. This is similar to @option{-gsplit-dwarf}, but this option
> +does not enable debugging information by itself.
> +
> @item -fvar-tracking
> @opindex fvar-tracking
> Run variable tracking pass. It computes where variables are stored at each
> --
> 2.26.2.645.ge9eca65c58-goog
>
