
Currently, the Ada expression parser treats 'null' as an integer 0. However, this causes overloading to fail in certain cases. This patch changes the Ada expression parser to use a special type for 'null'. I chose pointer-to-int0, because I think that's not likely to be needed for any other Ada expression. Note this works because a "mod 1" type has an underlying non-zero byte size; the test includes a check for this. The output is changed so that "print null", by default, shows "null". And, ada_type_match is changed both to recognize the special null type and to remove a bit of weird code related to how pointers are treated for overload type matching. Tested on x86-64 Fedora 32. Because this only touches Ada, and Joel already approved it internally at AdaCore, I am checking it in. gdb/ChangeLog 2021-04-28 Tom Tromey <tromey@adacore.com> * ada-exp.y (primary): Use new type for null pointer. * ada-lang.c (ada_type_match): Remove "may_deref" parameter. Handle null pointer. (ada_args_match): Update. * ada-valprint.c (ada_value_print_ptr, ada_value_print): Handle null pointer. gdb/testsuite/ChangeLog 2021-04-28 Tom Tromey <tromey@adacore.com> * gdb.ada/null_overload.exp: New file. * gdb.ada/null_overload/foo.adb: New file.
42 lines
1.1 KiB
Ada
42 lines
1.1 KiB
Ada
-- Copyright 2021 Free Software Foundation, Inc.
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--
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-- This program is free software; you can redistribute it and/or modify
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-- it under the terms of the GNU General Public License as published by
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-- the Free Software Foundation; either version 3 of the License, or
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-- (at your option) any later version.
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--
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-- This program is distributed in the hope that it will be useful,
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-- but WITHOUT ANY WARRANTY; without even the implied warranty of
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-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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-- GNU General Public License for more details.
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--
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-- You should have received a copy of the GNU General Public License
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-- along with this program. If not, see <http://www.gnu.org/licenses/>.
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procedure Foo is
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type R_Type is null record;
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type R_Access is access R_Type;
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type U_0 is mod 1;
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type U_P_T is access all U_0;
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function F (R : R_Access) return Boolean is
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begin
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return True;
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end F;
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function F (I : Integer) return Boolean is
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begin
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return False;
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end F;
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B1 : constant Boolean := F (null);
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B2 : constant Boolean := F (0);
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U : U_0 := 0;
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U_Ptr : U_P_T := null;
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begin
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null; -- START
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end Foo;
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