From db2534b704e5f1227decd2a0cfe62bff1d2bee65 Mon Sep 17 00:00:00 2001 From: Tom Tromey Date: Tue, 27 Apr 2021 07:35:23 -0600 Subject: [PATCH] Fix Ada overloading with 'null' 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 * 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 * gdb.ada/null_overload.exp: New file. * gdb.ada/null_overload/foo.adb: New file. --- gdb/ChangeLog | 9 +++++ gdb/ada-exp.y | 6 ++- gdb/ada-lang.c | 23 +++++------ gdb/ada-valprint.c | 15 +++++++- gdb/testsuite/ChangeLog | 5 +++ gdb/testsuite/gdb.ada/null_overload.exp | 37 ++++++++++++++++++ gdb/testsuite/gdb.ada/null_overload/foo.adb | 42 +++++++++++++++++++++ 7 files changed, 121 insertions(+), 16 deletions(-) create mode 100644 gdb/testsuite/gdb.ada/null_overload.exp create mode 100644 gdb/testsuite/gdb.ada/null_overload/foo.adb diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 3d266ea96bb..fa25ceec7d6 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,12 @@ +2021-04-28 Tom Tromey + + * 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. + 2021-04-28 Andrew Burgess * NEWS: Mention new commands. diff --git a/gdb/ada-exp.y b/gdb/ada-exp.y index 7b1b60fd46b..3652376b623 100644 --- a/gdb/ada-exp.y +++ b/gdb/ada-exp.y @@ -891,7 +891,11 @@ primary : FLOAT ; primary : NULL_PTR - { write_int (pstate, 0, type_int (pstate)); } + { + struct type *null_ptr_type + = lookup_pointer_type (parse_type (pstate)->builtin_int0); + write_int (pstate, 0, null_ptr_type); + } ; primary : STRING diff --git a/gdb/ada-lang.c b/gdb/ada-lang.c index 28f14c9ae53..0b50a788ac9 100644 --- a/gdb/ada-lang.c +++ b/gdb/ada-lang.c @@ -95,8 +95,6 @@ static struct type *desc_index_type (struct type *, int); static int desc_arity (struct type *); -static int ada_type_match (struct type *, struct type *, int); - static int ada_args_match (struct symbol *, struct value **, int); static struct value *make_array_descriptor (struct type *, struct value *); @@ -3492,14 +3490,12 @@ ada_resolve_variable (struct symbol *sym, const struct block *block, return candidates[i]; } -/* Return non-zero if formal type FTYPE matches actual type ATYPE. If - MAY_DEREF is non-zero, the formal may be a pointer and the actual - a non-pointer. */ +/* 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 int -ada_type_match (struct type *ftype, struct type *atype, int may_deref) +ada_type_match (struct type *ftype, struct type *atype) { ftype = ada_check_typedef (ftype); atype = ada_check_typedef (atype); @@ -3514,12 +3510,13 @@ ada_type_match (struct type *ftype, struct type *atype, int may_deref) default: return ftype->code () == atype->code (); case TYPE_CODE_PTR: - if (atype->code () == TYPE_CODE_PTR) - return ada_type_match (TYPE_TARGET_TYPE (ftype), - TYPE_TARGET_TYPE (atype), 0); - else - return (may_deref - && ada_type_match (TYPE_TARGET_TYPE (ftype), atype, 0)); + if (atype->code () != TYPE_CODE_PTR) + return 0; + atype = TYPE_TARGET_TYPE (atype); + /* This can only happen if the actual argument is 'null'. */ + if (atype->code () == TYPE_CODE_INT && TYPE_LENGTH (atype) == 0) + return 1; + return ada_type_match (TYPE_TARGET_TYPE (ftype), atype); case TYPE_CODE_INT: case TYPE_CODE_ENUM: case TYPE_CODE_RANGE: @@ -3580,7 +3577,7 @@ ada_args_match (struct symbol *func, struct value **actuals, int n_actuals) struct type *ftype = ada_check_typedef (func_type->field (i).type ()); struct type *atype = ada_check_typedef (value_type (actuals[i])); - if (!ada_type_match (ftype, atype, 1)) + if (!ada_type_match (ftype, atype)) return 0; } } diff --git a/gdb/ada-valprint.c b/gdb/ada-valprint.c index 61c903bbed5..d516a4d134e 100644 --- a/gdb/ada-valprint.c +++ b/gdb/ada-valprint.c @@ -719,6 +719,14 @@ ada_value_print_ptr (struct value *val, struct ui_file *stream, int recurse, const struct value_print_options *options) { + if (!options->format + && TYPE_TARGET_TYPE (value_type (val))->code () == TYPE_CODE_INT + && TYPE_LENGTH (TYPE_TARGET_TYPE (value_type (val))) == 0) + { + fputs_filtered ("null", stream); + return; + } + common_val_print (val, stream, recurse, options, language_def (language_c)); struct type *type = ada_check_typedef (value_type (val)); @@ -1096,8 +1104,11 @@ ada_value_print (struct value *val0, struct ui_file *stream, struct type *type = ada_check_typedef (value_type (val)); struct value_print_options opts; - /* If it is a pointer, indicate what it points to. */ - if (type->code () == TYPE_CODE_PTR) + /* If it is a pointer, indicate what it points to; but not for + "void *" pointers. */ + if (type->code () == TYPE_CODE_PTR + && !(TYPE_TARGET_TYPE (type)->code () == TYPE_CODE_INT + && TYPE_LENGTH (TYPE_TARGET_TYPE (type)) == 0)) { /* Hack: don't print (char *) for char strings. Their type is indicated by the quoted string anyway. */ diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog index d2ed989b17b..d4ed915881b 100644 --- a/gdb/testsuite/ChangeLog +++ b/gdb/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2021-04-28 Tom Tromey + + * gdb.ada/null_overload.exp: New file. + * gdb.ada/null_overload/foo.adb: New file. + 2021-04-28 Andrew Burgess * gdb.python/py-startup-opt.exp: New file. diff --git a/gdb/testsuite/gdb.ada/null_overload.exp b/gdb/testsuite/gdb.ada/null_overload.exp new file mode 100644 index 00000000000..e5b40de22f1 --- /dev/null +++ b/gdb/testsuite/gdb.ada/null_overload.exp @@ -0,0 +1,37 @@ +# Copyright 2021 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 . + +load_lib "ada.exp" + +if { [skip_ada_tests] } { return -1 } + +standard_ada_testfile foo + +if {[gdb_compile_ada "${srcfile}" "${binfile}" executable {debug}] != ""} { + return -1 +} + +clean_restart ${testfile} + +set bp_location [gdb_get_line_number "START" ${testdir}/foo.adb] +runto "foo.adb:$bp_location" + +gdb_test "print f(null)" " = true" +gdb_test "print f(r_access'(null))" " = true" +gdb_test "print f(0)" " = false" + +gdb_test "print null" " = null" +gdb_test "print/d null" " = 0" +gdb_test "print U_Ptr" " = \\\(access foo\\.u_0\\\) 0x0" diff --git a/gdb/testsuite/gdb.ada/null_overload/foo.adb b/gdb/testsuite/gdb.ada/null_overload/foo.adb new file mode 100644 index 00000000000..9a18606af39 --- /dev/null +++ b/gdb/testsuite/gdb.ada/null_overload/foo.adb @@ -0,0 +1,42 @@ +-- Copyright 2021 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 . + +procedure Foo is + + type R_Type is null record; + type R_Access is access R_Type; + + type U_0 is mod 1; + type U_P_T is access all U_0; + + function F (R : R_Access) return Boolean is + begin + return True; + end F; + + function F (I : Integer) return Boolean is + begin + return False; + end F; + + B1 : constant Boolean := F (null); + B2 : constant Boolean := F (0); + + U : U_0 := 0; + U_Ptr : U_P_T := null; + +begin + null; -- START +end Foo; -- 2.30.2