Re: [patch] PR python/11407

[Phil Muldoon <pmuldoon at redhat dot com>]

On 25/06/10 22:20, Phil Muldoon wrote:
> On 06/25/2010 07:25 PM, Tom Tromey wrote:
>>>>>>> "Phil" == Phil Muldoon <pmuldoon@redhat.com> writes:
>>
>> Phil> I'm not sure what to do in this case.  There seems to be no direct
>> Phil> equivalent of converting an exception to error output on a stream in MI
>> Phil> (or any cases of TRY ... exception handlers).  There are many cases of
>> Phil> MI raising an error() though, so I thought it appropriate in our case
>> Phil> to raise a warning() instead.  Because of the peculiarities of the MI
>> Phil> cases I just report a warning generically and move on.  This is not
>> Phil> totally ideal, but it does allow the error/warning preamble followed
>> Phil> by the actual locals information.
>>
>> I'm not convinced a warning is the best thing.
>>
>> Why not catch the exception and print the text of it as the variable's
>> value?  Something like  <error reading variable: %s>
>> I think this will work ok with existing front ends.
> 
> Here is a patch that does that.  
> 
> What do you think?
> 
> Cheers,
> 
> Phil
> 

Tom >> I am curious to hear what Volodya wants.


Adding Vladimir Prus to the CC list.  

Cheers,

Phil


> --
> 
> diff --git a/gdb/mi/mi-cmd-stack.c b/gdb/mi/mi-cmd-stack.c
> index 6797055..7ee075c 100644
> --- a/gdb/mi/mi-cmd-stack.c
> +++ b/gdb/mi/mi-cmd-stack.c
> @@ -31,7 +31,7 @@
>  #include "gdb_string.h"
>  #include "language.h"
>  #include "valprint.h"
> -
> +#include "exceptions.h"
>  
>  enum what_to_list { locals, arguments, all };
>  
> @@ -334,27 +334,47 @@ list_args_or_locals (enum what_to_list what, int values, struct frame_info *fi)
>  		      && TYPE_CODE (type) != TYPE_CODE_STRUCT
>  		      && TYPE_CODE (type) != TYPE_CODE_UNION)
>  		    {
> -		      struct value_print_options opts;
> -
> -		      val = read_var_value (sym2, fi);
> -		      get_raw_print_options (&opts);
> -		      opts.deref_ref = 1;
> -		      common_val_print
> -			(val, stb->stream, 0, &opts,
> -			 language_def (SYMBOL_LANGUAGE (sym2)));
> +		      volatile struct gdb_exception except;
> +
> +		      TRY_CATCH (except, RETURN_MASK_ERROR)
> +			{
> +			  struct value_print_options opts;
> +
> +			  val = read_var_value (sym2, fi);
> +			  get_raw_print_options (&opts);
> +			  opts.deref_ref = 1;
> +			  common_val_print
> +			    (val, stb->stream, 0, &opts,
> +			     language_def (SYMBOL_LANGUAGE (sym2)));
> +			}
> +		      if (except.reason < 0)
> +			fprintf_filtered (stb->stream,
> +					  _("<error reading variable: %s>"),
> +					  except.message);
> +
>  		      ui_out_field_stream (uiout, "value", stb);
>  		    }
>  		  break;
>  		case PRINT_ALL_VALUES:
>  		  {
> -		    struct value_print_options opts;
> -
> -		    val = read_var_value (sym2, fi);
> -		    get_raw_print_options (&opts);
> -		    opts.deref_ref = 1;
> -		    common_val_print
> -		      (val, stb->stream, 0, &opts,
> -		       language_def (SYMBOL_LANGUAGE (sym2)));
> +		    volatile struct gdb_exception except;
> +
> +		    TRY_CATCH (except, RETURN_MASK_ERROR)
> +		      {
> +			struct value_print_options opts;
> +
> +			val = read_var_value (sym2, fi);
> +			get_raw_print_options (&opts);
> +			opts.deref_ref = 1;
> +			common_val_print
> +			  (val, stb->stream, 0, &opts,
> +			   language_def (SYMBOL_LANGUAGE (sym2)));
> +		      }
> +		    if (except.reason < 0)
> +		      fprintf_filtered (stb->stream,
> +					_("<error reading variable: %s>"),
> +					except.message);
> +
>  		    ui_out_field_stream (uiout, "value", stb);
>  		  }
>  		  break;
> diff --git a/gdb/testsuite/gdb.mi/dw2-ref-missing-frame-func.c b/gdb/testsuite/gdb.mi/dw2-ref-missing-frame-func.c
> new file mode 100644
> index 0000000..10ddd81
> --- /dev/null
> +++ b/gdb/testsuite/gdb.mi/dw2-ref-missing-frame-func.c
> @@ -0,0 +1,54 @@
> +/* This testcase is part of GDB, the GNU debugger.
> +
> +   Copyright 2010 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/>.  */
> +
> +asm (".globl cu_text_start");
> +asm ("cu_text_start:");
> +
> +asm (".globl func_nofb_start");
> +asm ("func_nofb_start:");
> +
> +void
> +func_nofb (void)
> +{
> +  /* int func_nofb_var; */
> +  /* int func_nofb_var2; */
> +
> +  extern void func_nofb_marker (void);
> +  func_nofb_marker ();
> +}
> +
> +asm (".globl func_nofb_end");
> +asm ("func_nofb_end:");
> +
> +asm (".globl func_loopfb_start");
> +asm ("func_loopfb_start:");
> +
> +void
> +func_loopfb (void)
> +{
> +  /* int func_loopfb_var; */
> +  /* int func_loopfb_var2; */
> +
> +  extern void func_loopfb_marker (void);
> +  func_loopfb_marker ();
> +}
> +
> +asm (".globl func_loopfb_end");
> +asm ("func_loopfb_end:");
> +
> +asm (".globl cu_text_end");
> +asm ("cu_text_end:");
> diff --git a/gdb/testsuite/gdb.mi/dw2-ref-missing-frame-main.c b/gdb/testsuite/gdb.mi/dw2-ref-missing-frame-main.c
> new file mode 100644
> index 0000000..b3ec33a
> --- /dev/null
> +++ b/gdb/testsuite/gdb.mi/dw2-ref-missing-frame-main.c
> @@ -0,0 +1,40 @@
> +/* This testcase is part of GDB, the GNU debugger.
> +
> +   Copyright 2009, 2010 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/>.  */
> +
> +extern void func_nofb (void);
> +extern void func_loopfb (void);
> +
> +void
> +func_nofb_marker (void)
> +{
> +}
> +
> +void
> +func_loopfb_marker (void)
> +{
> +}
> +
> +int
> +main (void)
> +{
> +  int main_var = 1;
> +
> +  func_nofb ();
> +  func_loopfb ();
> +
> +  return 0;
> +}
> diff --git a/gdb/testsuite/gdb.mi/dw2-ref-missing-frame.S b/gdb/testsuite/gdb.mi/dw2-ref-missing-frame.S
> new file mode 100644
> index 0000000..a93b3a6
> --- /dev/null
> +++ b/gdb/testsuite/gdb.mi/dw2-ref-missing-frame.S
> @@ -0,0 +1,165 @@
> +/* This testcase is part of GDB, the GNU debugger.
> +
> +   Copyright 2007, 2008, 2009, 2010 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/>.  */
> +
> +/* Debug information */
> +
> +	.section .debug_info
> +.Lcu1_begin:
> +	/* CU header */
> +	.4byte	.Lcu1_end - .Lcu1_start		/* Length of Compilation Unit */
> +.Lcu1_start:
> +	.2byte	2				/* DWARF Version */
> +	.4byte	.Labbrev1_begin			/* Offset into abbrev section */
> +	.byte	4				/* Pointer size */
> +
> +	/* CU die */
> +	.uleb128 1				/* Abbrev: DW_TAG_compile_unit */
> +	.4byte	cu_text_end			/* DW_AT_high_pc */
> +	.4byte	cu_text_start			/* DW_AT_low_pc */
> +	.ascii	"file1.txt\0"			/* DW_AT_name */
> +	.ascii	"GNU C 3.3.3\0"			/* DW_AT_producer */
> +	.byte	1				/* DW_AT_language (C) */
> +
> +.Ltype_int:
> +	.uleb128	3			/* Abbrev: DW_TAG_base_type */
> +	.ascii		"int\0"			/* DW_AT_name */
> +	.byte		4			/* DW_AT_byte_size */
> +	.byte		5			/* DW_AT_encoding */
> +
> +	/* func_nofb */
> +	.uleb128	5			/* Abbrev: DW_TAG_subprogram (no fb) */
> +	.ascii		"func_nofb\0"		/* DW_AT_name */
> +	.4byte		func_nofb_start		/* DW_AT_low_pc */
> +	.4byte		func_nofb_end		/* DW_AT_high_pc */
> +
> +	.uleb128	7			/* Abbrev: DW_TAG_variable (location) */
> +	.ascii		"func_nofb_var\0"	/* DW_AT_name */
> +	.byte		2f - 1f			/* DW_AT_location */
> +1:	.byte		0x91			/*   DW_OP_fbreg */
> +	.sleb128	0			/*   0 */
> +2:	.4byte		.Ltype_int-.Lcu1_begin	/* DW_AT_type */
> +
> +	.uleb128	7			/* Abbrev: DW_TAG_variable (location) */
> +	.ascii		"func_nofb_var2\0"	/* DW_AT_name */
> +	.byte		2f - 1f			/* DW_AT_location */
> +1:	.byte		0x91			/*   DW_OP_fbreg */
> +	.sleb128	0			/*   0 */
> +2:	.4byte		.Ltype_int-.Lcu1_begin	/* DW_AT_type */
> +
> +	.byte		0			/* End of children of func */
> +
> +	/* func_loopfb */
> +	.uleb128	6			/* Abbrev: DW_TAG_subprogram (loop fb) */
> +	.ascii		"func_loopfb\0"		/* DW_AT_name */
> +	.4byte		func_loopfb_start	/* DW_AT_low_pc */
> +	.4byte		func_loopfb_end		/* DW_AT_high_pc */
> +	.byte		2f - 1f			/* DW_AT_frame_base */
> +1:	.byte		0x91			/*   DW_OP_fbreg */
> +	.sleb128	0			/*   0 */
> +2:
> +
> +	.uleb128	7			/* Abbrev: DW_TAG_variable (location) */
> +	.ascii		"func_loopfb_var\0"	/* DW_AT_name */
> +	.byte		2f - 1f			/* DW_AT_location */
> +1:	.byte		0x91			/*   DW_OP_fbreg */
> +	.sleb128	0			/*   0 */
> +2:	.4byte		.Ltype_int-.Lcu1_begin	/* DW_AT_type */
> +
> +	.uleb128	7			/* Abbrev: DW_TAG_variable (location) */
> +	.ascii		"func_loopfb_var2\0"	/* DW_AT_name */
> +	.byte		2f - 1f			/* DW_AT_location */
> +1:	.byte		0x91			/*   DW_OP_fbreg */
> +	.sleb128	0			/*   0 */
> +2:	.4byte		.Ltype_int-.Lcu1_begin	/* DW_AT_type */
> +
> +	.byte		0			/* End of children of func */
> +
> +	.byte		0			/* End of children of CU */
> +
> +.Lcu1_end:
> +
> +/* Abbrev table */
> +	.section .debug_abbrev
> +.Labbrev1_begin:
> +	.uleb128	1			/* Abbrev code */
> +	.uleb128	0x11			/* DW_TAG_compile_unit */
> +	.byte		1			/* has_children */
> +	.uleb128	0x12			/* DW_AT_high_pc */
> +	.uleb128	0x1			/* DW_FORM_addr */
> +	.uleb128	0x11			/* DW_AT_low_pc */
> +	.uleb128	0x1			/* DW_FORM_addr */
> +	.uleb128	0x3			/* DW_AT_name */
> +	.uleb128	0x8			/* DW_FORM_string */
> +	.uleb128	0x25			/* DW_AT_producer */
> +	.uleb128	0x8			/* DW_FORM_string */
> +	.uleb128	0x13			/* DW_AT_language */
> +	.uleb128	0xb			/* DW_FORM_data1 */
> +	.byte		0x0			/* Terminator */
> +	.byte		0x0			/* Terminator */
> +
> +	.uleb128	3			/* Abbrev code */
> +	.uleb128	0x24			/* DW_TAG_base_type */
> +	.byte		0			/* has_children */
> +	.uleb128	0x3			/* DW_AT_name */
> +	.uleb128	0x8			/* DW_FORM_string */
> +	.uleb128	0xb			/* DW_AT_byte_size */
> +	.uleb128	0xb			/* DW_FORM_data1 */
> +	.uleb128	0x3e			/* DW_AT_encoding */
> +	.uleb128	0xb			/* DW_FORM_data1 */
> +	.byte		0x0			/* Terminator */
> +	.byte		0x0			/* Terminator */
> +
> +	.uleb128	5			/* Abbrev code */
> +	.uleb128	0x2e			/* DW_TAG_subprogram (no fb) */
> +	.byte		1			/* has_children */
> +	.uleb128	0x3			/* DW_AT_name */
> +	.uleb128	0x8			/* DW_FORM_string */
> +	.uleb128	0x11			/* DW_AT_low_pc */
> +	.uleb128	0x1			/* DW_FORM_addr */
> +	.uleb128	0x12			/* DW_AT_high_pc */
> +	.uleb128	0x1			/* DW_FORM_addr */
> +	.byte		0x0			/* Terminator */
> +	.byte		0x0			/* Terminator */
> +
> +	.uleb128	6			/* Abbrev code */
> +	.uleb128	0x2e			/* DW_TAG_subprogram (loop fb) */
> +	.byte		1			/* has_children */
> +	.uleb128	0x3			/* DW_AT_name */
> +	.uleb128	0x8			/* DW_FORM_string */
> +	.uleb128	0x11			/* DW_AT_low_pc */
> +	.uleb128	0x1			/* DW_FORM_addr */
> +	.uleb128	0x12			/* DW_AT_high_pc */
> +	.uleb128	0x1			/* DW_FORM_addr */
> +	.uleb128	0x40			/* DW_AT_frame_base */
> +	.uleb128	0xa			/* DW_FORM_block1 */
> +	.byte		0x0			/* Terminator */
> +	.byte		0x0			/* Terminator */
> +
> +	.uleb128	7			/* Abbrev code (location) */
> +	.uleb128	0x34			/* DW_TAG_variable */
> +	.byte		0			/* has_children */
> +	.uleb128	0x3			/* DW_AT_name */
> +	.uleb128	0x8			/* DW_FORM_string */
> +	.uleb128	0x2			/* DW_AT_location */
> +	.uleb128	0xa			/* DW_FORM_block1 */
> +	.uleb128	0x49			/* DW_AT_type */
> +	.uleb128	0x13			/* DW_FORM_ref4 */
> +	.byte		0x0			/* Terminator */
> +	.byte		0x0			/* Terminator */
> +
> +	.byte		0x0			/* Terminator */
> +	.byte		0x0			/* Terminator */
> diff --git a/gdb/testsuite/gdb.mi/dw2-ref-missing-frame.exp b/gdb/testsuite/gdb.mi/dw2-ref-missing-frame.exp
> new file mode 100644
> index 0000000..cd29de5
> --- /dev/null
> +++ b/gdb/testsuite/gdb.mi/dw2-ref-missing-frame.exp
> @@ -0,0 +1,77 @@
> +# Copyright 2008, 2009, 2010 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/>.
> +
> +# This test can only be run on targets which support DWARF-2 and use gas.
> +# For now pick a sampling of likely targets.
> +load_lib mi-support.exp
> +set MIFLAGS "-i=mi"
> +
> +if {![istarget *-*-linux*]
> +    && ![istarget *-*-gnu*]
> +    && ![istarget *-*-elf*]
> +    && ![istarget *-*-openbsd*]
> +    && ![istarget arm-*-eabi*]
> +    && ![istarget powerpc-*-eabi*]} {
> +    return 0
> +}
> +
> +set testfile "dw2-ref-missing-frame"
> +set srcsfile ${testfile}.S
> +set objsfile ${objdir}/${subdir}/${testfile}.o
> +set srcfuncfile ${testfile}-func.c
> +set objfuncfile ${objdir}/${subdir}/${testfile}-func.o
> +set srcmainfile ${testfile}-main.c
> +set objmainfile ${objdir}/${subdir}/${testfile}-main.o
> +set executable ${testfile}
> +set binfile ${objdir}/${subdir}/${executable}
> +
> +if { [gdb_compile "${srcdir}/${subdir}/${srcsfile}" $objsfile object {}] != ""
> +     || [gdb_compile "${srcdir}/${subdir}/${srcfuncfile}" $objfuncfile object {}] != ""
> +     || [gdb_compile "${srcdir}/${subdir}/${srcmainfile}" $objmainfile object {debug}] != ""
> +     || [gdb_compile "$objsfile $objfuncfile $objmainfile" $binfile executable {}] != "" } {
> +    return -1
> +}
> +
> +if [mi_gdb_start] {
> +    continue
> +}
> +
> +mi_delete_breakpoints
> +mi_gdb_reinitialize_dir $srcdir/$subdir
> +mi_gdb_load ${binfile}
> +
> +if [mi_runto func_nofb_marker] {
> +    # First try referencing DW_AT_frame_base which is not defined.
> +    mi_gdb_test "300-stack-list-locals --thread 1 --frame 1 --all-values" \
> +	"300\\^done,locals=\\\[\{name=\"func_nofb_var\",value=\"\\\<error reading variable: Could not find the frame base for \\\\\"func_nofb\\\\\"\\\.\\\>\"\},\{name=\"func_nofb_var2\",value=\"\\\<error reading variable: Could not find the frame base for \\\\\"func_nofb\\\\\"\\\.\\\>\"\}\\\].*" \
> +	"test func_nofb_marker"
> +}
> +
> +# GDB could have crashed.
> +mi_gdb_exit
> +if [mi_gdb_start] {
> +    continue
> +}
> +mi_delete_breakpoints
> +mi_gdb_reinitialize_dir $srcdir/$subdir
> +mi_gdb_load ${binfile}
> +
> +# And now try referencing DW_AT_frame_base defined using a self-reference
> +# (DW_OP_fbreg).
> +if [mi_runto func_loopfb_marker] {
> +    mi_gdb_test "301-stack-list-locals --thread 1 --frame 1 --all-values" \
> +	"301\\^done,locals=\\\[\{name=\"func_loopfb_var\",value=\"\\\<error reading variable: DWARF-2 expression error: Loop detected.*\"\},\{name=\"func_loopfb_var2\",value=\"\\\<error reading variable: DWARF-2 expression error: Loop detected.*\"\}\\\]" \
> +	"test func_loopfb_var"
> +}