Re: [PATCH][gdb] Fix warning in foreach_arch selftests

Tom de Vries via Gdb-patches
2022-06-01T16:37:02Z

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On 6/1/22 16:32, Pedro Alves wrote:
> On 2022-06-01 11:41, Tom de Vries via Gdb-patches wrote:
>> Hi,
>>
>> When running the selftests, I run into:
>> ...
>> $ gdb -q -batch -ex "maint selftest"
>> ...
>> Running selftest execute_cfa_program::aarch64:ilp32.
>> warning: A handler for the OS ABI "GNU/Linux" is not built into this
>> configuration of GDB. Attempting to continue with the default aarch64:ilp32
>> settings.
>> ...
>> and likewise for execute_cfa_program::i8086 and
>> execute_cfa_program::ia64-elf32.
>>
>> The warning can easily be reproduced outside the selftests by doing:
>> ...
>> $ gdb -q -batch -ex "set arch aarch64:ilp32"
>> ...
>> and can be prevented by first doing "set osabi none".
>>
>> Fix the warning by setting osabi to none while doing selftests that iterate
>> over all architectures.
>>
>> Tested on x86_64-linux.
>>
>> Any comments?
>>
>> Thanks,
>> - Tom
>>
>> [gdb] Fix warning in foreach_arch selftests
>>
>> ---
>> gdb/osabi.c | 13 +++++++++++++
>> gdb/osabi.h | 6 ++++++
>> gdb/selftest-arch.c | 15 ++++++++++++++-
>> 3 files changed, 33 insertions(+), 1 deletion(-)
>>
>> diff --git a/gdb/osabi.c b/gdb/osabi.c
>> index bbd7635532f..c3f221df969 100644
>> --- a/gdb/osabi.c
>> +++ b/gdb/osabi.c
>> @@ -633,6 +633,19 @@ set_osabi (const char *args, int from_tty, struct cmd_list_element *c)
>> internal_error (__FILE__, __LINE__, _("Updating OS ABI failed."));
>> }
>>
>> +void
>> +set_osabi (const char *arg)
>> +{
>> + set_osabi_string = arg;
>> + set_osabi (NULL, 0, NULL);
>> +}
>> +
>> +const char *
>> +get_osabi ()
>> +{
>> + return set_osabi_string;
>> +}
>
> Missing usual "see foo.h" comments.
>

Hi,

thanks for the review.

Done.

>> +
>> static void
>> show_osabi (struct ui_file *file, int from_tty, struct cmd_list_element *c,
>> const char *value)
>> diff --git a/gdb/osabi.h b/gdb/osabi.h
>> index be016732cbc..eb5d88699e7 100644
>> --- a/gdb/osabi.h
>> +++ b/gdb/osabi.h
>> @@ -89,4 +89,10 @@ const char *osabi_triplet_regexp (enum gdb_osabi osabi);
>> void generic_elf_osabi_sniff_abi_tag_sections (bfd *, asection *,
>> enum gdb_osabi *);
>>
>> +/* Set osabi to ARG. */
>> +extern void set_osabi (const char *arg);
>> +
>> +/* Return current osabi setting. */
>> +extern const char *get_osabi ();
>> +
>> #endif /* OSABI_H */
>> diff --git a/gdb/selftest-arch.c b/gdb/selftest-arch.c
>> index f434da718d5..a631f52e31e 100644
>> --- a/gdb/selftest-arch.c
>> +++ b/gdb/selftest-arch.c
>> @@ -66,12 +66,25 @@ foreach_arch_test_generator (const std::string &name,
>> auto test_fn
>> = ([=] ()
>> {
>> + /* Prevent warnings when setting architecture with current osabi
>> + settings, like:
>> + A handler for the OS ABI "GNU/Linux" is not built into this
>> + configuration of GDB. Attempting to continue with the
>> + default aarch64:ilp32 settings. */
>> + const char *save_osabi = get_osabi ();
>> + set_osabi ("none");
>> +
>
> A bit of an odd API to have to pass the string name in. I'd think an API that
> takes an enum gdb_osabi would be better, as that way you don't have to worry
> about either passing the wrong string, or even worry about whether it's the
> string contents that counts (whether the function internally uses strcmp),
> or the string's address (the function internally compares pointers, assuming
> the only strings that will be passed down are the ones in the command's enum
> strings array).
>

Done.

>> struct gdbarch_info info;
>> info.bfd_arch_info = bfd_scan_arch (arch);
>> struct gdbarch *gdbarch = gdbarch_find_by_info (info);
>> SELF_CHECK (gdbarch != NULL);
>> +
>> function (gdbarch);
>> - reset ();
>> +
>> + SCOPE_EXIT {
>> + reset ();
>> + set_osabi (save_osabi);
>> + };
>
> Please format as:
>
> SCOPE_EXIT
> {
> reset ();
> set_osabi (save_osabi);
> };
>
> And you'll also need to move this to right after the set_osabi("none") call. Doing it
> here is too late. SCOPE_EXIT creates a RAII object on the stack, which needs to exist
> before any of the code that may throw right after set_osabi("none").
>

Done, thanks for catching that.

How does this look?

Thanks,
- Tom

[-- Attachment #2: 0002-gdb-Fix-warning-in-foreach_arch-selftests.patch --]
[-- Type: text/x-patch, Size: 5403 bytes --]

[gdb] Fix warning in foreach_arch selftests

When running the selftests, I run into:
...
$ gdb -q -batch -ex "maint selftest"
...
Running selftest execute_cfa_program::aarch64:ilp32.
warning: A handler for the OS ABI "GNU/Linux" is not built into this
configuration of GDB. Attempting to continue with the default aarch64:ilp32
settings.
...
and likewise for execute_cfa_program::i8086 and
execute_cfa_program::ia64-elf32.

The warning can easily be reproduced outside the selftests by doing:
...
$ gdb -q -batch -ex "set arch aarch64:ilp32"
...
and can be prevented by first doing "set osabi none".

Fix the warning by setting osabi to none while doing selftests that iterate
over all architectures.

Tested on x86_64-linux.

---
gdb/osabi.c | 50 ++++++++++++++++++++++++++++++++++++++------------
gdb/osabi.h | 13 +++++++++++++
gdb/selftest-arch.c | 18 +++++++++++++++++-
3 files changed, 68 insertions(+), 13 deletions(-)

diff --git a/gdb/osabi.c b/gdb/osabi.c
index bbd7635532f..776e62069e5 100644
--- a/gdb/osabi.c
+++ b/gdb/osabi.c
@@ -32,7 +32,7 @@
#endif

/* State for the "set osabi" command. */
-static enum { osabi_auto, osabi_default, osabi_user } user_osabi_state;
+static enum gdb_osabi_mode user_osabi_state;
static enum gdb_osabi user_selected_osabi;
static const char *gdb_osabi_available_names[GDB_OSABI_INVALID + 3] = {
"auto",
@@ -595,15 +595,48 @@ generic_elf_osabi_sniffer (bfd *abfd)
return osabi;
}
\f
+/* See osabi.h. */
+
+void
+set_osabi (enum gdb_osabi_mode mode, enum gdb_osabi osabi)
+{
+ if (mode == osabi_auto)
+ user_osabi_state = osabi_auto;
+ else if (mode == osabi_default)
+ {
+ user_selected_osabi = GDB_OSABI_DEFAULT;
+ user_osabi_state = osabi_user;
+ }
+ else
+ {
+ user_selected_osabi = osabi;
+ user_osabi_state = osabi_user;
+ }
+
+ /* NOTE: At some point (true multiple architectures) we'll need to be more
+ graceful here. */
+ gdbarch_info info;
+ if (! gdbarch_update_p (info))
+ internal_error (__FILE__, __LINE__, _("Updating OS ABI failed."));
+}
+
+/* See osabi.h. */
+
+void
+get_osabi (enum gdb_osabi_mode &mode, enum gdb_osabi &osabi)
+{
+ mode = user_osabi_state;
+ osabi = user_selected_osabi;
+}
+
static void
set_osabi (const char *args, int from_tty, struct cmd_list_element *c)
{
if (strcmp (set_osabi_string, "auto") == 0)
- user_osabi_state = osabi_auto;
+ set_osabi (osabi_auto, GDB_OSABI_INVALID);
else if (strcmp (set_osabi_string, "default") == 0)
{
- user_selected_osabi = GDB_OSABI_DEFAULT;
- user_osabi_state = osabi_user;
+ set_osabi (osabi_default, GDB_OSABI_INVALID);
}
else
{
@@ -615,8 +648,7 @@ set_osabi (const char *args, int from_tty, struct cmd_list_element *c)

if (strcmp (set_osabi_string, gdbarch_osabi_name (osabi)) == 0)
{
- user_selected_osabi = osabi;
- user_osabi_state = osabi_user;
+ set_osabi (osabi_user, osabi);
break;
}
}
@@ -625,12 +657,6 @@ set_osabi (const char *args, int from_tty, struct cmd_list_element *c)
_("Invalid OS ABI \"%s\" passed to command handler."),
set_osabi_string);
}
-
- /* NOTE: At some point (true multiple architectures) we'll need to be more
- graceful here. */
- gdbarch_info info;
- if (! gdbarch_update_p (info))
- internal_error (__FILE__, __LINE__, _("Updating OS ABI failed."));
}

static void
diff --git a/gdb/osabi.h b/gdb/osabi.h
index be016732cbc..3737a77d50e 100644
--- a/gdb/osabi.h
+++ b/gdb/osabi.h
@@ -50,6 +50,13 @@ enum gdb_osabi
GDB_OSABI_INVALID /* keep this last */
};

+enum gdb_osabi_mode
+{
+ osabi_auto,
+ osabi_default,
+ osabi_user
+};
+
/* Register an OS ABI sniffer. Each arch/flavour may have more than
one sniffer. This is used to e.g. differentiate one OS's a.out from
another. The first sniffer to return something other than
@@ -89,4 +96,10 @@ const char *osabi_triplet_regexp (enum gdb_osabi osabi);
void generic_elf_osabi_sniff_abi_tag_sections (bfd *, asection *,
enum gdb_osabi *);

+/* Set osabi to MODE/OSABI. */
+extern void set_osabi (enum gdb_osabi_mode mode, enum gdb_osabi osabi);
+
+/* Return current osabi setting in MODE/OSABI. */
+extern void get_osabi (enum gdb_osabi_mode &mode, enum gdb_osabi &osabi);
+
#endif /* OSABI_H */
diff --git a/gdb/selftest-arch.c b/gdb/selftest-arch.c
index f434da718d5..a4d9de5a74d 100644
--- a/gdb/selftest-arch.c
+++ b/gdb/selftest-arch.c
@@ -66,12 +66,28 @@ foreach_arch_test_generator (const std::string &name,
auto test_fn
= ([=] ()
{
+ /* Prevent warnings when setting architecture with current osabi
+ settings, like:
+ A handler for the OS ABI "GNU/Linux" is not built into this
+ configuration of GDB. Attempting to continue with the
+ default aarch64:ilp32 settings. */
+ enum gdb_osabi_mode mode;
+ enum gdb_osabi osabi;
+ get_osabi (mode, osabi);
+
+ set_osabi (osabi_user, GDB_OSABI_NONE);
+ SCOPE_EXIT
+ {
+ reset ();
+ set_osabi (mode, osabi);
+ };
+
struct gdbarch_info info;
info.bfd_arch_info = bfd_scan_arch (arch);
struct gdbarch *gdbarch = gdbarch_find_by_info (info);
SELF_CHECK (gdbarch != NULL);
+
function (gdbarch);
- reset ();
});

tests.emplace_back (string_printf ("%s::%s", name.c_str (), arch),