[PATCH] Pass void_context_p to parse_expression

Joel Brobecker brobecker@adacore.com
Fri Jan 8 06:54:36 GMT 2021


Hi Tom,

On Thu, Jan 07, 2021 at 06:55:27AM -0700, Tom Tromey wrote:
> Joel> In looking at the testcase, it inspired me to modify the testcase
> Joel> we have in house to use counters to keep track of which function
> Joel> gets called, when it gets called and how many times. What do you think
> Joel> of doing the same here?
> 
> Sure, how about the appended?

Thanks, looks good!

> commit c8438c9f872a65811d99589ee7095c12e75d2144
> Author: Tom Tromey <tromey@adacore.com>
> Date:   Fri Dec 18 08:02:08 2020 -0700
> 
>     Pass void_context_p to parse_expression
>     
>     An earlier patch pointed out that nothing in GDB sets void_context_p
>     when parsing an expression.  This patch fixes this omission.
>     
>     "print" and "call" differ in that the former will print a value that
>     has void type, while the latter will not.  AdaCore has had a patch for
>     a long time that uses this distinction to help with overload
>     resolution.  In particular, in a "call" context, a procedure will be
>     chosen, while in a "print" context, a zero-argument function will be
>     chosen instead.
>     
>     Regression tested on x86-64 Fedora 32.
>     
>     gdb/ChangeLog
>     2020-12-18  Tom Tromey  <tromey@adacore.com>
>     
>             * parse.c (parse_expression): Add void_context_p parameter.  Use
>             parse_exp_in_context.
>             * printcmd.c (print_command_1): Change voidprint to bool.  Pass to
>             parse_expression.
>             (print_command, call_command): Update.
>             * expression.h (parse_expression): Add void_context_p parameter.
>     
>     gdb/testsuite/ChangeLog
>     2020-12-18  Tom Tromey  <tromey@adacore.com>
>     
>             * gdb.ada/voidctx/pck.adb: New file.
>             * gdb.ada/voidctx/pck.ads: New file.
>             * gdb.ada/voidctx/voidctx.adb: New file.
>             * gdb.ada/voidctx.exp: New file.
> 
> diff --git a/gdb/ChangeLog b/gdb/ChangeLog
> index 44dfabf62d4..739b129f1e9 100644
> --- a/gdb/ChangeLog
> +++ b/gdb/ChangeLog
> @@ -1,3 +1,12 @@
> +2020-12-18  Tom Tromey  <tromey@adacore.com>
> +
> +	* parse.c (parse_expression): Add void_context_p parameter.  Use
> +	parse_exp_in_context.
> +	* printcmd.c (print_command_1): Change voidprint to bool.  Pass to
> +	parse_expression.
> +	(print_command, call_command): Update.
> +	* expression.h (parse_expression): Add void_context_p parameter.
> +
>  2021-01-06  Tom Tromey  <tromey@adacore.com>
>  
>  	* ada-lang.c (ada_evaluate_subexp) <BINOP_ADD, BINOP_SUB>:
> diff --git a/gdb/expression.h b/gdb/expression.h
> index 8c0bcc90f15..e70169e9b3e 100644
> --- a/gdb/expression.h
> +++ b/gdb/expression.h
> @@ -142,7 +142,8 @@ typedef std::unique_ptr<expression> expression_up;
>  
>  class innermost_block_tracker;
>  extern expression_up parse_expression (const char *,
> -				       innermost_block_tracker * = nullptr);
> +				       innermost_block_tracker * = nullptr,
> +				       bool void_context_p = false);
>  
>  extern expression_up parse_expression_with_language (const char *string,
>  						     enum language lang);
> diff --git a/gdb/parse.c b/gdb/parse.c
> index 51e7d65ad07..b3cd91d2730 100644
> --- a/gdb/parse.c
> +++ b/gdb/parse.c
> @@ -1158,13 +1158,20 @@ parse_exp_in_context (const char **stringptr, CORE_ADDR pc,
>    return result;
>  }
>  
> -/* Parse STRING as an expression, and complain if this fails
> -   to use up all of the contents of STRING.  */
> +/* Parse STRING as an expression, and complain if this fails to use up
> +   all of the contents of STRING.  TRACKER, if non-null, will be
> +   updated by the parser.  VOID_CONTEXT_P should be true to indicate
> +   that the expression may be expected to return a value with void
> +   type.  Parsers are free to ignore this, or to use it to help with
> +   overload resolution decisions.  */
>  
>  expression_up
> -parse_expression (const char *string, innermost_block_tracker *tracker)
> +parse_expression (const char *string, innermost_block_tracker *tracker,
> +		  bool void_context_p)
>  {
> -  expression_up exp = parse_exp_1 (&string, 0, 0, 0, tracker);
> +  expression_up exp = parse_exp_in_context (&string, 0, nullptr, 0,
> +					    void_context_p, nullptr,
> +					    tracker, nullptr);
>    if (*string)
>      error (_("Junk after end of expression."));
>    return exp;
> diff --git a/gdb/printcmd.c b/gdb/printcmd.c
> index a1c9af1acae..2e56d28e9f4 100644
> --- a/gdb/printcmd.c
> +++ b/gdb/printcmd.c
> @@ -1206,7 +1206,7 @@ print_value (value *val, const value_print_options &opts)
>  /* Implementation of the "print" and "call" commands.  */
>  
>  static void
> -print_command_1 (const char *args, int voidprint)
> +print_command_1 (const char *args, bool voidprint)
>  {
>    struct value *val;
>    value_print_options print_opts;
> @@ -1223,7 +1223,9 @@ print_command_1 (const char *args, int voidprint)
>  
>    if (exp != nullptr && *exp)
>      {
> -      expression_up expr = parse_expression (exp);
> +      /* VOIDPRINT is true to indicate that we do want to print a void
> +	 value, so invert it for parse_expression.  */
> +      expression_up expr = parse_expression (exp, nullptr, !voidprint);
>        val = evaluate_expression (expr.get ());
>      }
>    else
> @@ -1321,14 +1323,14 @@ print_command_completer (struct cmd_list_element *ignore,
>  static void
>  print_command (const char *exp, int from_tty)
>  {
> -  print_command_1 (exp, 1);
> +  print_command_1 (exp, true);
>  }
>  
>  /* Same as print, except it doesn't print void results.  */
>  static void
>  call_command (const char *exp, int from_tty)
>  {
> -  print_command_1 (exp, 0);
> +  print_command_1 (exp, false);
>  }
>  
>  /* Implementation of the "output" command.  */
> diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
> index 8d5a2ee4599..e696632f296 100644
> --- a/gdb/testsuite/ChangeLog
> +++ b/gdb/testsuite/ChangeLog
> @@ -1,3 +1,10 @@
> +2020-12-18  Tom Tromey  <tromey@adacore.com>
> +
> +	* gdb.ada/voidctx/pck.adb: New file.
> +	* gdb.ada/voidctx/pck.ads: New file.
> +	* gdb.ada/voidctx/voidctx.adb: New file.
> +	* gdb.ada/voidctx.exp: New file.
> +
>  2021-01-06  Tom Tromey  <tromey@adacore.com>
>  
>  	* gdb.ada/fixed_points/pck.ads (Delta4): New constant.
> diff --git a/gdb/testsuite/gdb.ada/voidctx.exp b/gdb/testsuite/gdb.ada/voidctx.exp
> new file mode 100644
> index 00000000000..c557c1fe8d0
> --- /dev/null
> +++ b/gdb/testsuite/gdb.ada/voidctx.exp
> @@ -0,0 +1,40 @@
> +# 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 <http://www.gnu.org/licenses/>.
> +
> +load_lib "ada.exp"
> +
> +if { [skip_ada_tests] } { return -1 }
> +
> +standard_ada_testfile voidctx
> +
> +if {[gdb_compile_ada "${srcfile}" "${binfile}" executable [list debug ]] != "" } {
> +  return -1
> +}
> +
> +clean_restart ${testfile}
> +
> +set bp_location [gdb_get_line_number "STOP" ${testdir}/voidctx.adb]
> +runto "voidctx.adb:$bp_location"
> +
> +gdb_test "print pck.proc_count" " = 0" "initial proc_count"
> +gdb_test "print pck.func_count" " = 0" "initial func_count"
> +
> +gdb_test "print DoSomething" " = 42"
> +gdb_test "print pck.proc_count" " = 0" "check proc_count 1"
> +gdb_test "print pck.func_count" " = 1" "check func_count 1"
> +
> +gdb_test_no_output "call DoSomething"
> +gdb_test "print pck.proc_count" " = 1" "check proc_count 2"
> +gdb_test "print pck.func_count" " = 1" "check func_count 2"
> diff --git a/gdb/testsuite/gdb.ada/voidctx/pck.adb b/gdb/testsuite/gdb.ada/voidctx/pck.adb
> new file mode 100644
> index 00000000000..bdd76cd4142
> --- /dev/null
> +++ b/gdb/testsuite/gdb.ada/voidctx/pck.adb
> @@ -0,0 +1,27 @@
> +--  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 <http://www.gnu.org/licenses/>.
> +
> +package body Pck is
> +   function DoSomething return Integer is
> +   begin
> +      Func_Count := Func_Count + 1;
> +      return 42;
> +   end;
> +
> +   procedure DoSomething is
> +   begin
> +      Proc_Count := Proc_Count + 1;
> +   end;
> +end Pck;
> diff --git a/gdb/testsuite/gdb.ada/voidctx/pck.ads b/gdb/testsuite/gdb.ada/voidctx/pck.ads
> new file mode 100644
> index 00000000000..cf7fe15e6fb
> --- /dev/null
> +++ b/gdb/testsuite/gdb.ada/voidctx/pck.ads
> @@ -0,0 +1,23 @@
> +--  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 <http://www.gnu.org/licenses/>.
> +
> +package Pck is
> +   -- Each count is incremented by the respective DoSomething.
> +   Proc_Count : Integer := 0;
> +   Func_Count : Integer := 0;
> +
> +   function DoSomething return Integer;
> +   procedure DoSomething;
> +end Pck;
> diff --git a/gdb/testsuite/gdb.ada/voidctx/voidctx.adb b/gdb/testsuite/gdb.ada/voidctx/voidctx.adb
> new file mode 100644
> index 00000000000..8059a2be81b
> --- /dev/null
> +++ b/gdb/testsuite/gdb.ada/voidctx/voidctx.adb
> @@ -0,0 +1,31 @@
> +--  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 <http://www.gnu.org/licenses/>.
> +
> +with Pck; use Pck;
> +procedure Voidctx is	      
> +
> +   function DoSomething return Integer is
> +   begin
> +      return 42;
> +   end;
> +
> +   procedure DoSomething is
> +   begin
> +      null;
> +   end;
> +
> +begin
> +   null;  -- STOP
> +end Voidctx;

-- 
Joel


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