[2/2] Refine Ada overload matching
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Commit Message
Currently, the overload handling in Ada assumes that any two array
types are compatible. However, this is obviously untrue, and a user
reported an oddity where comparing two Ada strings resulted in a call
to the "=" function for packed boolean arrays.
This patch improves the situation somewhat, by requiring that the two
arrays have the same arity and compatible base element types. This is
still over-broad, but it seems safe and is better than the status quo.
---
gdb/ada-lang.c | 45 ++++++++++++++++++++-------
gdb/testsuite/gdb.ada/overloads.exp | 33 ++++++++++++++++++++
gdb/testsuite/gdb.ada/overloads/overloads.adb | 41 ++++++++++++++++++++++++
3 files changed, 108 insertions(+), 11 deletions(-)
@@ -3930,9 +3930,35 @@ ada_resolve_variable (struct symbol *sym, const struct block *block,
return candidates[i];
}
-/* Return non-zero if formal type FTYPE matches actual type ATYPE. */
-/* The term "match" here is rather loose. The match is heuristic and
- liberal. */
+static bool ada_type_match (struct type *ftype, struct type *atype);
+
+/* Helper for ada_type_match that checks that two array types are
+ compatible. As with that function, FTYPE is the formal type and
+ ATYPE is the actual type. */
+
+static bool
+ada_type_match_arrays (struct type *ftype, struct type *atype)
+{
+ if (ftype->code () != TYPE_CODE_ARRAY
+ && !ada_is_array_descriptor_type (ftype))
+ return false;
+ if (atype->code () != TYPE_CODE_ARRAY
+ && !ada_is_array_descriptor_type (atype))
+ return false;
+
+ if (ada_array_arity (ftype) != ada_array_arity (atype))
+ return false;
+
+ struct type *f_elt_type = ada_array_element_type (ftype, -1);
+ struct type *a_elt_type = ada_array_element_type (atype, -1);
+ return ada_type_match (f_elt_type, a_elt_type);
+}
+
+/* Return non-zero if formal type FTYPE matches actual type ATYPE.
+ The term "match" here is rather loose. The match is heuristic and
+ liberal -- while it tries to reject matches that are obviously
+ incorrect, it may still let through some that do not strictly
+ correspond to Ada rules. */
static bool
ada_type_match (struct type *ftype, struct type *atype)
@@ -3970,18 +3996,15 @@ ada_type_match (struct type *ftype, struct type *atype)
return false;
}
- case TYPE_CODE_ARRAY:
- return (atype->code () == TYPE_CODE_ARRAY
- || ada_is_array_descriptor_type (atype));
-
case TYPE_CODE_STRUCT:
- if (ada_is_array_descriptor_type (ftype))
- return (atype->code () == TYPE_CODE_ARRAY
- || ada_is_array_descriptor_type (atype));
- else
+ if (!ada_is_array_descriptor_type (ftype))
return (atype->code () == TYPE_CODE_STRUCT
&& !ada_is_array_descriptor_type (atype));
+ [[fallthrough]];
+ case TYPE_CODE_ARRAY:
+ return ada_type_match_arrays (ftype, atype);
+
case TYPE_CODE_UNION:
case TYPE_CODE_FLT:
return (atype->code () == ftype->code ());
new file mode 100644
@@ -0,0 +1,33 @@
+# Copyright 2021-2023 Free Software Foundation, Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+load_lib "ada.exp"
+
+require allow_ada_tests
+
+standard_ada_testfile overloads
+
+if {[gdb_compile_ada "${srcfile}" "${binfile}" executable {debug}] != ""} {
+ return -1
+}
+
+clean_restart ${testfile}
+
+set bp_location [gdb_get_line_number "START" ${testdir}/overloads.adb]
+runto "overloads.adb:$bp_location"
+
+# Before the fix, these would show overload menus.
+gdb_test "print Oload(PA)" " = 23"
+gdb_test "print Oload(CA)" " = 91"
new file mode 100644
@@ -0,0 +1,41 @@
+-- Copyright 2023 Free Software Foundation, Inc.
+--
+-- This program is free software; you can redistribute it and/or modify
+-- it under the terms of the GNU General Public License as published by
+-- the Free Software Foundation; either version 3 of the License, or
+-- (at your option) any later version.
+--
+-- This program is distributed in the hope that it will be useful,
+-- but WITHOUT ANY WARRANTY; without even the implied warranty of
+-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+-- GNU General Public License for more details.
+--
+-- You should have received a copy of the GNU General Public License
+-- along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+procedure Overloads is
+
+ type Packed_Array is array (4 .. 7) of Boolean;
+ pragma pack (Packed_Array);
+
+ type Char_Array is array (1 .. 4) of Character;
+
+ function Oload (P : Packed_Array) return Integer is
+ begin
+ return 23;
+ end Oload;
+
+ function Oload (C : Char_Array) return Integer is
+ begin
+ return 91;
+ end Oload;
+
+ PA : Packed_Array := (True, False, True, False);
+ CA : Char_Array := ('A', 'B', 'C', 'D');
+
+ B1 : constant Integer := Oload (PA);
+ B2 : constant Integer := Oload (CA);
+
+begin
+ null; -- START
+end Overloads;