On Tue, Sep 21, 2021 at 4:26 PM Richard Biener via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> This makes defaults.h choose DWARF2_DEBUG if PREFERRED_DEBUGGING_TYPE
> is not specified by the target and errors out if DWARF DWARF is not supported.
>
> It also makes us warn when STABS is enabled but not the preferred
> debugging type and removes the corresponding diagnostic from the Ada frontend.
> The warnings are pruned from the testsuite output via prune_gcc_output.
>
> The following target configurations now explicitely default to STABS:
> pdp11-*-* pdp11 is a.out, dwarf support is difficult
> hppa[12]*-*-hpux10* does not support DWARF
> hppa[12]*-*-hpux11* likewise
> note that the hppa configs have been deprecated.
>
> Targets with DWARF support will now see
> > ./cc1 -quiet t.c -gstabs
> t.c: warning: STABS debugging information is obsolete and not supported
> anymore
>
> that is, -gstabs will still generate STABS but use will be diagnosed
> on targets where DWARF is available.
>
> I have built all targets from contrib/config-list.mk to make sure we
> don't run into the #error and the following makes the STABS usage
> explicit for pdp11 and hppa with SOM.
>
> This completes the series of deprecating STABS for GCC 12.
>
> Bootstrapped and tested on x86_64-unknown-linux-gnu.
>
> OK for trunk?
Ping.
> Thanks,
> Richard.
>
> 2021-09-21 Richard Biener <rguent...@suse.de>
>
> gcc/
> * defaults.h (PREFERRED_DEBUGGING_TYPE): Choose DWARF2_DEBUG
> when not set.
> * toplev.c (process_options): Warn when STABS debugging is
> enabled but not the preferred format.
> * config/pa/som.h (PREFERRED_DEBUGGING_TYPE): Define to
> DBX_DEBUG.
> * config/pdp11/pdp11.h (PREFERRED_DEBUGGING_TYPE): Likewise.
>
> gcc/ada/
> * gcc-interface/misc.c (gnat_post_options): Do not warn
> about DBX_DEBUG use here.
>
> gcc/testsuite/
> * lib/prune.exp: Prune STABS obsoletion message.
> ---
> gcc/ada/gcc-interface/misc.c | 6 ------
> gcc/config/pa/som.h | 4 ++++
> gcc/config/pdp11/pdp11.h | 3 +++
> gcc/defaults.h | 29 +++++------------------------
> gcc/testsuite/lib/prune.exp | 3 +++
> gcc/toplev.c | 5 +++++
> 6 files changed, 20 insertions(+), 30 deletions(-)
>
> diff --git a/gcc/ada/gcc-interface/misc.c b/gcc/ada/gcc-interface/misc.c
> index 96199bd4b63..87a4c8662cb 100644
> --- a/gcc/ada/gcc-interface/misc.c
> +++ b/gcc/ada/gcc-interface/misc.c
> @@ -274,12 +274,6 @@ gnat_post_options (const char **pfilename
> ATTRIBUTE_UNUSED)
> if (!global_options_set.x_flag_diagnostics_show_caret)
> global_dc->show_caret = false;
>
> - /* Warn only if STABS is not the default: we don't want to emit a warning
> if
> - the user did not use a -gstabs option. */
> - if (PREFERRED_DEBUGGING_TYPE != DBX_DEBUG && write_symbols == DBX_DEBUG)
> - warning (0, "STABS debugging information for Ada is obsolete and not "
> - "supported anymore");
> -
> /* Copy global settings to local versions. */
> gnat_encodings = global_options.x_gnat_encodings;
> optimize = global_options.x_optimize;
> diff --git a/gcc/config/pa/som.h b/gcc/config/pa/som.h
> index 05cc315b9f9..36a1122b132 100644
> --- a/gcc/config/pa/som.h
> +++ b/gcc/config/pa/som.h
> @@ -21,6 +21,10 @@ along with GCC; see the file COPYING3. If not see
> #undef TARGET_SOM
> #define TARGET_SOM 1
>
> +/* With SOM we can only do STABS. */
> +#undef PREFERRED_DEBUGGING_TYPE
> +#define PREFERRED_DEBUGGING_TYPE DBX_DEBUG
> +
> /* We do not use BINCL stabs in SOM.
> ??? If it does not hurt, we probably should to avoid useless divergence
> from other embedded stabs implementations. */
> diff --git a/gcc/config/pdp11/pdp11.h b/gcc/config/pdp11/pdp11.h
> index 9bc5e089f49..91a8ce70751 100644
> --- a/gcc/config/pdp11/pdp11.h
> +++ b/gcc/config/pdp11/pdp11.h
> @@ -54,6 +54,9 @@ along with GCC; see the file COPYING3. If not see
>
> #define DBX_DEBUGGING_INFO
>
> +#undef PREFERRED_DEBUGGING_TYPE
> +#define PREFERRED_DEBUGGING_TYPE DBX_DEBUG
> +
> #define TARGET_40_PLUS (TARGET_40 || TARGET_45)
> #define TARGET_10 (! TARGET_40_PLUS)
>
> diff --git a/gcc/defaults.h b/gcc/defaults.h
> index ba79a8e48ed..d7f2546f2cc 100644
> --- a/gcc/defaults.h
> +++ b/gcc/defaults.h
> @@ -900,33 +900,14 @@ see the files COPYING3 and COPYING.RUNTIME
> respectively. If not, see
> #define DEFAULT_GDB_EXTENSIONS 1
> #endif
>
> -/* If more than one debugging type is supported, you must define
> - PREFERRED_DEBUGGING_TYPE to choose the default. */
> -
> -#if 1 < (defined (DBX_DEBUGGING_INFO) \
> - + defined (DWARF2_DEBUGGING_INFO) + defined (XCOFF_DEBUGGING_INFO) \
> - + defined (VMS_DEBUGGING_INFO))
> +/* Default to DWARF2_DEBUGGING_INFO. Legacy targets can choose different
> + by defining PREFERRED_DEBUGGING_TYPE. */
> #ifndef PREFERRED_DEBUGGING_TYPE
> -#error You must define PREFERRED_DEBUGGING_TYPE
> -#endif /* no PREFERRED_DEBUGGING_TYPE */
> -
> -/* If only one debugging format is supported, define PREFERRED_DEBUGGING_TYPE
> - here so other code needn't care. */
> -#elif defined DBX_DEBUGGING_INFO
> -#define PREFERRED_DEBUGGING_TYPE DBX_DEBUG
> -
> -#elif defined DWARF2_DEBUGGING_INFO || defined DWARF2_LINENO_DEBUGGING_INFO
> +#if defined DWARF2_DEBUGGING_INFO || defined DWARF2_LINENO_DEBUGGING_INFO
> #define PREFERRED_DEBUGGING_TYPE DWARF2_DEBUG
> -
> -#elif defined VMS_DEBUGGING_INFO
> -#define PREFERRED_DEBUGGING_TYPE VMS_AND_DWARF2_DEBUG
> -
> -#elif defined XCOFF_DEBUGGING_INFO
> -#define PREFERRED_DEBUGGING_TYPE XCOFF_DEBUG
> -
> #else
> -/* No debugging format is supported by this target. */
> -#define PREFERRED_DEBUGGING_TYPE NO_DEBUG
> +#error You must define PREFERRED_DEBUGGING_TYPE if DWARF is not supported
> +#endif
> #endif
>
> #ifndef FLOAT_LIB_COMPARE_RETURNS_BOOL
> diff --git a/gcc/testsuite/lib/prune.exp b/gcc/testsuite/lib/prune.exp
> index fac212ecf60..131424861d5 100644
> --- a/gcc/testsuite/lib/prune.exp
> +++ b/gcc/testsuite/lib/prune.exp
> @@ -93,6 +93,9 @@ proc prune_gcc_output { text } {
> # Ignore dsymutil warning (tool bug is actually linker)
> regsub -all "(^|\n)\[^\n\]*could not find object file symbol for
> symbol\[^\n\]*" $text "" text
>
> + # Ignore stabs obsoletion warnings
> + regsub -all "(^|\n)\[^\n\]*\[Ww\]arning: STABS debugging information is
> obsolete and not supported anymore\[^\n\]*" $text "" text
> +
> # If dg-enable-nn-line-numbers was provided, then obscure source-margin
> # line numbers by converting them to "NN" form.
> set text [maybe-handle-nn-line-numbers $text]
> diff --git a/gcc/toplev.c b/gcc/toplev.c
> index 14d1335e79e..8de8a92f2c6 100644
> --- a/gcc/toplev.c
> +++ b/gcc/toplev.c
> @@ -1452,6 +1452,11 @@ process_options (void)
> && ctf_debug_info_level == CTFINFO_LEVEL_NONE)
> write_symbols = NO_DEBUG;
>
> + /* Warn if STABS debug gets enabled and is not the default. */
> + if (PREFERRED_DEBUGGING_TYPE != DBX_DEBUG && (write_symbols & DBX_DEBUG))
> + warning (0, "STABS debugging information is obsolete and not "
> + "supported anymore");
> +
> if (write_symbols == NO_DEBUG)
> ;
> #if defined(DBX_DEBUGGING_INFO)
> --
> 2.31.1
