Fix comparison of array types
Checks
Context |
Check |
Description |
linaro-tcwg-bot/tcwg_gdb_build--master-aarch64 |
success
|
Testing passed
|
linaro-tcwg-bot/tcwg_gdb_build--master-arm |
success
|
Testing passed
|
linaro-tcwg-bot/tcwg_gdb_check--master-aarch64 |
success
|
Testing passed
|
linaro-tcwg-bot/tcwg_gdb_check--master-arm |
success
|
Testing passed
|
Commit Message
Currently it's not possible to call functions if an argument is a
pointer to an array:
```
(gdb) l f
1 int f (int (*x)[2])
2 {
3 return x[0][1];
4 }
5
6 int main()
7 {
8 int a[2][2] = {{0, 1}, {2, 3}};
9 return f (a);
10 }
(gdb) p f(a)
Cannot resolve function f to any overloaded instance
```
This happens because types_equal doesn't handle array types, so the
function is never even considered as a possibility.
With array type handling added, by comparing element types and array
bounds, the same works:
```
(gdb) p f(a)
$1 = 1
```
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=15398
Co-Authored-By: Keith Seitz <keiths@redhat.com>
---
gdb/gdbtypes.c | 13 +++++++++++++
gdb/testsuite/gdb.cp/converts.exp | 1 +
2 files changed, 14 insertions(+)
Comments
Ping.
Am Freitag, 9. Februar 2024 um 20:46:35 MEZ hat Hannes Domani <ssbssa@yahoo.de> Folgendes geschrieben:
> Currently it's not possible to call functions if an argument is a
> pointer to an array:
> ```
> (gdb) l f
> 1 int f (int (*x)[2])
> 2 {
> 3 return x[0][1];
> 4 }
> 5
> 6 int main()
> 7 {
> 8 int a[2][2] = {{0, 1}, {2, 3}};
> 9 return f (a);
> 10 }
> (gdb) p f(a)
> Cannot resolve function f to any overloaded instance
> ```
>
> This happens because types_equal doesn't handle array types, so the
> function is never even considered as a possibility.
>
> With array type handling added, by comparing element types and array
> bounds, the same works:
> ```
> (gdb) p f(a)
> $1 = 1
> ```
>
> Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=15398
> Co-Authored-By: Keith Seitz <keiths@redhat.com>
> ---
> gdb/gdbtypes.c | 13 +++++++++++++
> gdb/testsuite/gdb.cp/converts.exp | 1 +
> 2 files changed, 14 insertions(+)
>
> diff --git a/gdb/gdbtypes.c b/gdb/gdbtypes.c
> index dcd7321d979..6c0d20b2daf 100644
> --- a/gdb/gdbtypes.c
> +++ b/gdb/gdbtypes.c
> @@ -4202,6 +4202,19 @@ types_equal (struct type *a, struct type *b)
> return true;
> }
>
> + /* Two array types are the same if they have the same element types
> + and array bounds. */
> + if (a->code () == TYPE_CODE_ARRAY)
> + {
> + if (!types_equal (a->target_type (), b->target_type ()))
> + return false;
> +
> + if (*a->bounds () != *b->bounds ())
> + return false;
> +
> + return true;
> + }
> +
> return false;
> }
>
> diff --git a/gdb/testsuite/gdb.cp/converts.exp b/gdb/testsuite/gdb.cp/converts.exp
> index bf608bdcccd..6ea21fec563 100644
> --- a/gdb/testsuite/gdb.cp/converts.exp
> +++ b/gdb/testsuite/gdb.cp/converts.exp
> @@ -48,6 +48,7 @@ gdb_test "p foo1_8 (bp)" "Using non-standard.*" "pointer to long int"
> gdb_test "p foo1_5 (b)" "= 15" "pointer pointer to void pointer"
> gdb_test "p foo2_1 (b)" "= 21" "pointer pointer to pointer pointer"
> gdb_test "p foo2_2 (b)" "Cannot resolve.*" "pointer pointer to array of arrays"
> +gdb_test "p foo2_2 (ba)" "= 22" "array of arrays to array of arrays"
> gdb_test "p foo2_3 (b)" "= 23" "pointer pointer to array of pointers"
> gdb_test "p foo2_4 (b)" "Cannot resolve.*" "pointer pointer to array of wrong pointers"
>
> --
> 2.35.1
On 09/02/2024 20:45, Hannes Domani wrote:
> Currently it's not possible to call functions if an argument is a
> pointer to an array:
> ```
> (gdb) l f
> 1 int f (int (*x)[2])
> 2 {
> 3 return x[0][1];
> 4 }
> 5
> 6 int main()
> 7 {
> 8 int a[2][2] = {{0, 1}, {2, 3}};
> 9 return f (a);
> 10 }
> (gdb) p f(a)
> Cannot resolve function f to any overloaded instance
> ```
>
> This happens because types_equal doesn't handle array types, so the
> function is never even considered as a possibility.
>
> With array type handling added, by comparing element types and array
> bounds, the same works:
> ```
> (gdb) p f(a)
> $1 = 1
> ```
>
> Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=15398
> Co-Authored-By: Keith Seitz <keiths@redhat.com>
Hi!
This patch fixes the problem (for both gcc and clang) and introduces no
regressions.
My one nitpick is that I think this code fits more naturally right after
the pointer check, instead of the last check in the function, but feel
free to disagree. Either way: Reviewed-By: Guinevere Larsen
<blarsen@redhat.com>
Am Donnerstag, 29. Februar 2024 um 14:26:16 MEZ hat Guinevere Larsen <blarsen@redhat.com> Folgendes geschrieben:
> On 09/02/2024 20:45, Hannes Domani wrote:
> > Currently it's not possible to call functions if an argument is a
> > pointer to an array:
> > ```
> > (gdb) l f
> > 1 int f (int (*x)[2])
> > 2 {
> > 3 return x[0][1];
> > 4 }
> > 5
> > 6 int main()
> > 7 {
> > 8 int a[2][2] = {{0, 1}, {2, 3}};
> > 9 return f (a);
> > 10 }
> > (gdb) p f(a)
> > Cannot resolve function f to any overloaded instance
> > ```
> >
> > This happens because types_equal doesn't handle array types, so the
> > function is never even considered as a possibility.
> >
> > With array type handling added, by comparing element types and array
> > bounds, the same works:
> > ```
> > (gdb) p f(a)
> > $1 = 1
> > ```
> >
> > Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=15398
> > Co-Authored-By: Keith Seitz <keiths@redhat.com>
>
> Hi!
>
> This patch fixes the problem (for both gcc and clang) and introduces no
> regressions.
>
> My one nitpick is that I think this code fits more naturally right after
> the pointer check, instead of the last check in the function, but feel
> free to disagree. Either way: Reviewed-By: Guinevere Larsen
> <blarsen@redhat.com>
Either position is fine for me.
Hannes
>>>>> "Hannes" == Hannes Domani <ssbssa@yahoo.de> writes:
Hannes> This happens because types_equal doesn't handle array types, so the
Hannes> function is never even considered as a possibility.
Hannes> With array type handling added, by comparing element types and array
Hannes> bounds, the same works:
Sorry about the delay on this. This is OK.
Approved-By: Tom Tromey <tom@tromey.com>
Tom
>>>>> Guinevere Larsen <blarsen@redhat.com> writes:
> My one nitpick is that I think this code fits more naturally right
> after the pointer check, instead of the last check in the function,
> but feel free to disagree. Either way: Reviewed-By: Guinevere Larsen
> <blarsen@redhat.com>
This would make sense too, but I'm not sure how much it matters.
In most languages, array types don't have a name anyway.
Also I wonder if we really want to keep all these different
type-equality functions around. Right now there is types_equal,
types_deeply_equal, and also ada_type_match.
The Ada one is maybe hard to remove as long as GNAT encodings are
relevant. However maybe we could replace types_equal with
types_deeply_equal everywhere.
Tom
Am Montag, 18. März 2024 um 17:20:38 MEZ hat Tom Tromey <tom@tromey.com> Folgendes geschrieben:
> >>>>> "Hannes" == Hannes Domani <ssbssa@yahoo.de> writes:
>
> Hannes> This happens because types_equal doesn't handle array types, so the
> Hannes> function is never even considered as a possibility.
>
> Hannes> With array type handling added, by comparing element types and array
> Hannes> bounds, the same works:
>
> Sorry about the delay on this. This is OK.
>
> Approved-By: Tom Tromey <tom@tromey.com>
Pushed, thanks.
Hannes
@@ -4202,6 +4202,19 @@ types_equal (struct type *a, struct type *b)
return true;
}
+ /* Two array types are the same if they have the same element types
+ and array bounds. */
+ if (a->code () == TYPE_CODE_ARRAY)
+ {
+ if (!types_equal (a->target_type (), b->target_type ()))
+ return false;
+
+ if (*a->bounds () != *b->bounds ())
+ return false;
+
+ return true;
+ }
+
return false;
}
@@ -48,6 +48,7 @@ gdb_test "p foo1_8 (bp)" "Using non-standard.*" "pointer to long int"
gdb_test "p foo1_5 (b)" "= 15" "pointer pointer to void pointer"
gdb_test "p foo2_1 (b)" "= 21" "pointer pointer to pointer pointer"
gdb_test "p foo2_2 (b)" "Cannot resolve.*" "pointer pointer to array of arrays"
+gdb_test "p foo2_2 (ba)" "= 22" "array of arrays to array of arrays"
gdb_test "p foo2_3 (b)" "= 23" "pointer pointer to array of pointers"
gdb_test "p foo2_4 (b)" "Cannot resolve.*" "pointer pointer to array of wrong pointers"