--- Begin Message ---
|
Subject: |
It is annoying to have to type 'print foo' before each .gdbinit command. |
|
Date: |
Sun, 12 Feb 2023 13:01:57 +0000 |
Hello, Emacs.
In a GDB session, whilst debugging Emacs, it is common to want to print,
for example, the current value of Lisp variable foo. At the moment, one
has to type
p foo
xpr
.. This need, continually to type p (or print) is irritating. It should
be possible simply to type
xpr foo
.. The same applies to many other commands in .gdbinit.
The following patch fixes this irritation. It allows a user to type xpr
foo, yet also preserves the old version with no arguments, which can be
handy, sometimes.
I propose this patch be applied to the master branch.
diff --git a/etc/DEBUG b/etc/DEBUG
index c4f0852abb3..5fa60af2806 100644
--- a/etc/DEBUG
+++ b/etc/DEBUG
@@ -288,9 +288,10 @@ and where you interact with GDB.
** Examining Lisp object values.
When you have a live process to debug, and it has not encountered a
-fatal error, you can use the GDB command 'pr'. First print the value
-in the ordinary way, with the 'p' command. Then type 'pr' with no
-arguments. This calls a subroutine which uses the Lisp printer.
+fatal error, you can use the GDB command 'pr'. Just type pr, giving
+the object as the argument. (The older method of first printing with
+the 'p' command followed by pr without arguments still works.) This
+calls a subroutine which uses the Lisp printer.
You can also use 'pp value' to print the emacs value directly.
@@ -319,8 +320,7 @@ If you can't use 'pr' command, for whatever reason, you can
use the
'xpr' command to print out the data type and value of the last data
value, For example:
- p it->object
- xpr
+ xpr it->object
You may also analyze data values using lower-level commands. Use the
'xtype' command to print out the data type of the last data value.
@@ -328,10 +328,10 @@ Once you know the data type, use the command that
corresponds to that
type. Here are these commands:
xint xptr xwindow xmarker xoverlay xmiscfree xintfwd xboolfwd xobjfwd
- xbufobjfwd xkbobjfwd xbuflocal xbuffer xsymbol xstring xvector xframe
- xwinconfig xcompiled xcons xcar xcdr xsubr xprocess xfloat xscrollbar
- xchartable xsubchartable xboolvector xhashtable xlist xcoding
- xcharset xfontset xfont
+ xbufobjfwd xkbobjfwd xbuflocal xbuffer xsymbol xsymwithpos xstring
+ xvector xframe xwinconfig xcompiled xcons xcar xcdr xsubr xprocess
+ xfloat xscrollbar xchartable xsubchartable xboolvector xhashtable
+ xlist xcoding xcharset xfontset xfont
Each one of them applies to a certain type or class of types.
(Some of these types are not visible in Lisp, because they exist only
@@ -357,15 +357,13 @@ called frame. First, use these commands:
Then Emacs hits the breakpoint:
- (gdb) p frame
- $1 = 139854428
- (gdb) xpr
+ (gdb) xpr frame
Lisp_Vectorlike
PVEC_FRAME
- $2 = (struct frame *) 0x8560258
+ $1 = (struct frame *) 0x8560258
"emacs@localhost"
(gdb) p *$
- $3 = {
+ $2 = {
size = 1073742931,
next = 0x85dfe58,
name = 140615219,
@@ -391,22 +389,19 @@ evaluate expressions like "p XVECTOR (this_command_keys)".
When this information isn't available, you can use the xvector command in GDB
to get the same result. Here is how:
- (gdb) p this_command_keys
- $1 = 1078005760
- (gdb) xvector
- $2 = (struct Lisp_Vector *) 0x411000
+ (gdb) xvector this_command_keys
+ $1 = (struct Lisp_Vector *) 0x411000
0
(gdb) p $->contents[this_command_key_count]
- $3 = 1077872640
+ $2 = 1077872640
(gdb) p &$
- $4 = (int *) 0x411008
+ $3 = (int *) 0x411008
Here's a related example of macros and the GDB 'define' command.
There are many Lisp vectors such as 'recent_keys', which contains the
last 300 keystrokes. We can print this Lisp vector
- p recent_keys
- pr
+ pr recent_keys
But this may be inconvenient, since 'recent_keys' is much more verbose
than 'C-h l'. We might want to print only the last 10 elements of
@@ -447,8 +442,7 @@ backtrace, and look for stack frames that call Ffuncall.
Select them
one by one in GDB, by typing "up N", where N is the appropriate number
of frames to go up, and in each frame that calls Ffuncall type this:
- p *args
- pr
+ pr *args
This will print the name of the Lisp function called by that level
of function calling.
@@ -456,15 +450,13 @@ of function calling.
By printing the remaining elements of args, you can see the argument
values. Here's how to print the first argument:
- p args[1]
- pr
+ pr args[1]
If you do not have a live process, you can use xtype and the other
x... commands such as xsymbol to get such information, albeit less
conveniently. For example:
- p *args
- xtype
+ xtype *args
and, assuming that "xtype" says that args[0] is a symbol:
diff --git a/src/.gdbinit b/src/.gdbinit
index c96c2b597bd..65ef9a5684e 100644
--- a/src/.gdbinit
+++ b/src/.gdbinit
@@ -91,10 +91,15 @@ end
# from calling OutputDebugString, which causes GDB to display each
# character twice (yuk!).
define pr
- pp $
+ if $argc > 0
+ set $d = $arg0
+ else
+ set $d = $
+ end
+ pp $d
end
document pr
-Print the emacs s-expression which is $.
+Print the emacs s-expression which is $arg0 or $.
Works only when an inferior emacs is executing.
end
@@ -656,15 +661,20 @@ Takes one argument, a pointer to a glyph_matrix structure.
end
define xtype
- xgettype $
+ if $argc > 0
+ set $d = $arg0
+ else
+ set $d = $
+ end
+ xgettype $d
output $type
echo \n
if $type == Lisp_Vectorlike
- xvectype
+ xvectype $d
end
end
document xtype
-Print the type of $, assuming it is an Emacs Lisp value.
+Print the type of $arg0 or $, assuming it is an Emacs Lisp value.
If the first type printed is Lisp_Vectorlike,
a second line gives the more precise type.
end
@@ -684,12 +694,17 @@ Takes one argument, a pointer to an object.
end
define xvectype
- xgetptr $
+ if $argc > 0
+ set $d = $arg0
+ else
+ set $d = $
+ end
+ xgetptr $d
pvectype $ptr
end
document xvectype
Print the subtype of vectorlike object.
-This command assumes that $ is a Lisp_Object.
+This command assumes that $arg0 or $ is a Lisp_Object.
end
define pvecsize
@@ -709,104 +724,159 @@ Takes one argument, a pointer to an object.
end
define xvecsize
- xgetptr $
+ if $argc > 0
+ set $d = $arg0
+ else
+ set $d = $
+ end
+ xgetptr $d
pvecsize $ptr
end
document xvecsize
-Print the size of $
-This command assumes that $ is a Lisp_Object.
+Print the size of $arg0 or $.
+This command assumes that $arg0 or $ is a Lisp_Object.
end
define xint
- xgetint $
+ if $argc > 0
+ set $d = $arg0
+ else
+ set $d = $
+ end
+ xgetint $d
print $int
end
document xint
-Print $ as an Emacs Lisp integer. This gets the sign right.
+Print $arg0 or $ as an Emacs Lisp integer. This gets the sign right.
end
define xptr
- xgetptr $
+ if $argc > 0
+ set $d = $arg0
+ else
+ set $d = $
+ end
+ xgetptr $d
print (void *) $ptr
end
document xptr
-Print the pointer portion of an Emacs Lisp value in $.
+Print the pointer portion of an Emacs Lisp value in $arg0 or $.
end
define xmarker
- xgetptr $
+ if $argc > 0
+ set $d = $arg0
+ else
+ set $d = $
+ end
+ xgetptr $d
print (struct Lisp_Marker *) $ptr
end
document xmarker
-Print $ as a marker pointer.
+Print $arg0 or $ as a marker pointer.
This command assumes that $ is an Emacs Lisp marker value.
end
define xoverlay
- xgetptr $
+ if $argc > 0
+ set $d = $arg0
+ else
+ set $d = $
+ end
+ xgetptr $d
print (struct Lisp_Overlay *) $ptr
end
document xoverlay
-Print $ as a overlay pointer.
-This command assumes that $ is an Emacs Lisp overlay value.
+Print $arg0 or $ as a overlay pointer.
+This command assumes that $arg0 or $ is an Emacs Lisp overlay value.
end
define xsymwithpos
- xgetptr $
+ if $argc > 0
+ set $d = $arg0
+ else
+ set $d = $
+ end
+ xgetptr $d
print (struct Lisp_Symbol_With_Pos *) $ptr
end
document xsymwithpos
-Print $ as a symbol with position.
-This command assumes that $ is an Emacs Lisp symbol with position value.
+Print $arg0 or $ as a symbol with position.
+This command assumes that $arg0 or $ is an Emacs Lisp symbol with position
value.
end
define xsymbol
- set $sym = $
+ if $argc > 0
+ set $d = $arg0
+ else
+ set $d = $
+ end
+ set $sym = $d
xgetsym $sym
print (struct Lisp_Symbol *) $ptr
xprintsym $sym
echo \n
end
document xsymbol
-Print the name and address of the symbol $.
-This command assumes that $ is an Emacs Lisp symbol value.
+Print the name and address of the symbol $arg0 or $.
+This command assumes that $arg0 or $ is an Emacs Lisp symbol value.
end
define xstring
- xgetptr $
+ if $argc > 0
+ set $d = $arg0
+ else
+ set $d = $
+ end
+ xgetptr $d
print (struct Lisp_String *) $ptr
xprintstr $
echo \n
end
document xstring
-Print the contents and address of the string $.
-This command assumes that $ is an Emacs Lisp string value.
+Print the contents and address of the string $arg0 or $.
+This command assumes that $arg0 or $ is an Emacs Lisp string value.
end
define xvector
- xgetptr $
+ if $argc > 0
+ set $d = $arg0
+ else
+ set $d = $
+ end
+ xgetptr $d
print (struct Lisp_Vector *) $ptr
output ($->header.size > 50) ? 0 : ($->contents[0])@($->header.size &
~ARRAY_MARK_FLAG)
echo \n
end
document xvector
-Print the contents and address of the vector $.
-This command assumes that $ is an Emacs Lisp vector value.
+Print the contents and address of the vector $arg0 or $.
+This command assumes that $arg0 or $ is an Emacs Lisp vector value.
end
define xprocess
- xgetptr $
+ if $argc > 0
+ set $d = $arg0
+ else
+ set $d = $
+ end
+ xgetptr $d
print (struct Lisp_Process *) $ptr
- output *$
+ output *$d
echo \n
end
document xprocess
-Print the address of the struct Lisp_process to which $ points.
-This command assumes that $ is a Lisp_Object.
+Print the address of the struct Lisp_process to which $arg0 or $ points.
+This command assumes that $arg0 or $ is a Lisp_Object.
end
define xframe
- xgetptr $
+ if $argc > 0
+ set $d = $arg0
+ else
+ set $d = $
+ end
+ xgetptr $d
print (struct frame *) $ptr
xgetptr $->name
set $ptr = (struct Lisp_String *) $ptr
@@ -814,53 +884,78 @@ define xframe
echo \n
end
document xframe
-Print $ as a frame pointer.
-This command assumes $ is an Emacs Lisp frame value.
+Print $arg0 or $ as a frame pointer.
+This command assumes $arg0 or $ is an Emacs Lisp frame value.
end
define xcompiled
- xgetptr $
+ if $argc > 0
+ set $d = $arg0
+ else
+ set $d = $
+ end
+ xgetptr $d
print (struct Lisp_Vector *) $ptr
output ($->contents[0])@($->header.size & 0xff)
echo \n
end
document xcompiled
-Print $ as a compiled function pointer.
-This command assumes that $ is an Emacs Lisp compiled value.
+Print $arg0 or $ as a compiled function pointer.
+This command assumes that $arg0 or $ is an Emacs Lisp compiled value.
end
define xwindow
- xgetptr $
+ if $argc > 0
+ set $d = $arg0
+ else
+ set $d = $
+ end
+ xgetptr $d
print (struct window *) $ptr
set $window = (struct window *) $ptr
printf "%dx%d+%d+%d\n", $window->total_cols, $window->total_lines,
$window->left_col, $window->top_line
end
document xwindow
-Print $ as a window pointer, assuming it is an Emacs Lisp window value.
+Print $arg0 or $ as a window pointer, assuming it is an Emacs Lisp window
value.
Print the window's position as "WIDTHxHEIGHT+LEFT+TOP".
end
define xwinconfig
- xgetptr $
+ if $argc > 0
+ set $d = $arg0
+ else
+ set $d = $
+ end
+ xgetptr $d
print (struct save_window_data *) $ptr
end
document xwinconfig
-Print $ as a window configuration pointer.
-This command assumes that $ is an Emacs Lisp window configuration value.
+Print $arg0 or $ as a window configuration pointer.
+This command assumes that $arg0 or $ is an Emacs Lisp window configuration
value.
end
define xsubr
- xgetptr $
+ if $argc > 0
+ set $d = $arg0
+ else
+ set $d = $
+ end
+ xgetptr $d
print (struct Lisp_Subr *) $ptr
output *$
echo \n
end
document xsubr
-Print the address of the subr which the Lisp_Object $ points to.
+Print the address of the subr which the Lisp_Object $arg0 or $ points to.
end
define xchartable
- xgetptr $
+ if $argc > 0
+ set $d = $arg0
+ else
+ set $d = $
+ end
+ xgetptr $d
print (struct Lisp_Char_Table *) $ptr
printf "Purpose: "
xprintsym $->purpose
@@ -868,65 +963,90 @@ define xchartable
echo \n
end
document xchartable
-Print the address of the char-table $, and its purpose.
-This command assumes that $ is an Emacs Lisp char-table value.
+Print the address of the char-table $arg0 or $, and its purpose.
+This command assumes that $arg0 or $ is an Emacs Lisp char-table value.
end
define xsubchartable
- xgetptr $
+ if $argc > 0
+ set $d = $arg0
+ else
+ set $d = $
+ end
+ xgetptr $d
print (struct Lisp_Sub_Char_Table *) $ptr
set $subchartab = (struct Lisp_Sub_Char_Table *) $ptr
printf "Depth: %d, Min char: %d (0x%x)\n", $subchartab->depth,
$subchartab->min_char, $subchartab->min_char
end
document xsubchartable
-Print the address of the sub-char-table $, its depth and min-char.
-This command assumes that $ is an Emacs Lisp sub-char-table value.
+Print the address of the sub-char-table $arg0 or $, its depth and min-char.
+This command assumes that $arg0 or $ is an Emacs Lisp sub-char-table value.
end
define xboolvector
- xgetptr $
+ if $argc > 0
+ set $d = $arg0
+ else
+ set $d = $
+ end
+ xgetptr $d
print (struct Lisp_Bool_Vector *) $ptr
output ($->size > 256) ? 0 : ($->data[0])@(($->size +
BOOL_VECTOR_BITS_PER_CHAR - 1)/ BOOL_VECTOR_BITS_PER_CHAR)
echo \n
end
document xboolvector
-Print the contents and address of the bool-vector $.
-This command assumes that $ is an Emacs Lisp bool-vector value.
+Print the contents and address of the bool-vector $arg0 or $.
+This command assumes that $arg0 or $ is an Emacs Lisp bool-vector value.
end
define xbuffer
- xgetptr $
+ if $argc > 0
+ set $d = $arg0
+ else
+ set $d = $
+ end
+ xgetptr $d
print (struct buffer *) $ptr
xgetptr $->name_
output $ptr ? (char *) ((struct Lisp_String *) $ptr)->u.s.data : "DEAD"
echo \n
end
document xbuffer
-Set $ as a buffer pointer and the name of the buffer.
-This command assumes $ is an Emacs Lisp buffer value.
+Set $arg0 or $ as a buffer pointer and the name of the buffer.
+This command assumes $arg0 or $ is an Emacs Lisp buffer value.
end
define xhashtable
- xgetptr $
+ if $argc > 0
+ set $d = $arg0
+ else
+ set $d = $
+ end
+ xgetptr $d
print (struct Lisp_Hash_Table *) $ptr
end
document xhashtable
-Set $ as a hash table pointer.
-This command assumes that $ is an Emacs Lisp hash table value.
+Set $arg0 or $ as a hash table pointer.
+This command assumes that $arg0 or $ is an Emacs Lisp hash table value.
end
define xcons
- xgetptr $
+ if $argc > 0
+ set $d = $arg0
+ else
+ set $d = $
+ end
+ xgetptr $d
print (struct Lisp_Cons *) $ptr
output/x *$
echo \n
end
document xcons
-Print the contents of $ as an Emacs Lisp cons.
+Print the contents of $arg0 or $ as an Emacs Lisp cons.
end
define nextcons
- p $.u.cdr
+ p $.u.s.u.cdr
xcons
end
document nextcons
@@ -935,25 +1055,40 @@ This command assumes that the last thing you printed was
a cons cell contents
(type struct Lisp_Cons) or a pointer to one.
end
define xcar
- xgetptr $
- xgettype $
+ if $argc > 0
+ set $d = $arg0
+ else
+ set $d = $
+ end
+ xgetptr $d
+ xgettype $d
print/x ($type == Lisp_Cons ? ((struct Lisp_Cons *) $ptr)->u.s.car : 0)
end
document xcar
-Assume that $ is an Emacs Lisp pair and print its car.
+Assume that $arg0 or $ is an Emacs Lisp pair and print its car.
end
define xcdr
- xgetptr $
- xgettype $
+ if $argc > 0
+ set $d = $arg0
+ else
+ set $d = $
+ end
+ xgetptr $d
+ xgettype $d
print/x ($type == Lisp_Cons ? ((struct Lisp_Cons *) $ptr)->u.s.u.cdr : 0)
end
document xcdr
-Assume that $ is an Emacs Lisp pair and print its cdr.
+Assume that $arg0 or $ is an Emacs Lisp pair and print its cdr.
end
define xlist
- xgetptr $
+ if $argc > 0
+ set $d = $arg0
+ else
+ set $d = $
+ end
+ xgetptr $d
set $cons = (struct Lisp_Cons *) $ptr
xgetptr Qnil
set $nil = $ptr
@@ -974,97 +1109,112 @@ define xlist
end
end
document xlist
-Print $ assuming it is a list.
+Print $arg0 or $ assuming it is a list.
end
define xfloat
- xgetptr $
+ if $argc > 0
+ set $d = $arg0
+ else
+ set $d = $
+ end
+ xgetptr $d
print ((struct Lisp_Float *) $ptr)->u.data
end
document xfloat
-Print $ assuming it is a lisp floating-point number.
+Print $arg0 or $ assuming it is a lisp floating-point number.
end
define xscrollbar
- xgetptr $
+ if $argc > 0
+ set $d = $arg0
+ else
+ set $d = $
+ end
+ xgetptr $d
print (struct scrollbar *) $ptr
-output *$
+output *$d
echo \n
end
document xscrollbar
-Print $ as a scrollbar pointer.
+Print $arg0 or $ as a scrollbar pointer.
end
define xpr
- xtype
+ if $argc > 0
+ set $d = $arg0
+ else
+ set $d = $
+ end
+ xtype $d
if $type == Lisp_Int0 || $type == Lisp_Int1
- xint
+ xint $d
end
if $type == Lisp_Symbol
- xsymbol
+ xsymbol $d
end
if $type == Lisp_String
- xstring
+ xstring $d
end
if $type == Lisp_Cons
- xcons
+ xcons $d
end
if $type == Lisp_Float
- xfloat
+ xfloat $d
end
if $type == Lisp_Vectorlike
set $size = ((struct Lisp_Vector *) $ptr)->header.size
if ($size & PSEUDOVECTOR_FLAG)
set $vec = (enum pvec_type) (($size & PVEC_TYPE_MASK) >>
PSEUDOVECTOR_AREA_BITS)
if $vec == PVEC_NORMAL_VECTOR
- xvector
+ xvector $d
end
if $vec == PVEC_MARKER
- xmarker
+ xmarker $d
end
if $vec == PVEC_OVERLAY
- xoverlay
+ xoverlay $d
end
if $vec == PVEC_SYMBOL_WITH_POS
- xsymwithpos
+ xsymwithpos $d
end
if $vec == PVEC_PROCESS
- xprocess
+ xprocess $d
end
if $vec == PVEC_FRAME
- xframe
+ xframe $d
end
if $vec == PVEC_COMPILED
- xcompiled
+ xcompiled $d
end
if $vec == PVEC_WINDOW
- xwindow
+ xwindow $d
end
if $vec == PVEC_WINDOW_CONFIGURATION
- xwinconfig
+ xwinconfig $d
end
if $vec == PVEC_SUBR
- xsubr
+ xsubr $d
end
if $vec == PVEC_CHAR_TABLE
- xchartable
+ xchartable $d
end
if $vec == PVEC_BOOL_VECTOR
- xboolvector
+ xboolvector $d
end
if $vec == PVEC_BUFFER
- xbuffer
+ xbuffer $d
end
if $vec == PVEC_HASH_TABLE
- xhashtable
+ xhashtable $d
end
else
- xvector
+ xvector $d
end
end
end
document xpr
-Print $ as a lisp object of any type.
+Print $arg0 or $ as a lisp object of any type.
end
define xprintstr
@@ -1118,7 +1268,12 @@ document xcharset
end
define xfontset
- xgetptr $
+ if $argc > 0
+ set $d = $arg0
+ else
+ set $d = $
+ end
+ xgetptr $d
set $tbl = (struct Lisp_Char_Table *) $ptr
print $tbl
xgetint $tbl->extras[0]
@@ -1141,7 +1296,12 @@ define xfontset
end
define xfont
- xgetptr $
+ if $argc > 0
+ set $d = $arg0
+ else
+ set $d = $
+ end
+ xgetptr $d
set $size = (((struct Lisp_Vector *) $ptr)->header.size & 0x1FF)
if $size == FONT_SPEC_MAX
print (struct font_spec *) $ptr
@@ -1154,7 +1314,7 @@ define xfont
end
end
document xfont
-Print $ assuming it is a list font (font-spec, font-entity, or font-object).
+Print $arg0 or $ assuming it is a list font (font-spec, font-entity, or
font-object).
end
define xbacktrace
--
Alan Mackenzie (Nuremberg, Germany).
--- End Message ---
--- Begin Message ---
|
Subject: |
Re: bug#61453: It is annoying to have to type 'print foo' before each .gdbinit command. |
|
Date: |
Sun, 12 Feb 2023 18:56:44 +0000 |
tags 61453 wontfix
quit
Hello, Eli.
On Sun, Feb 12, 2023 at 20:33:07 +0200, Eli Zaretskii wrote:
> > Date: Sun, 12 Feb 2023 18:23:36 +0000
> > Cc: 61453@debbugs.gnu.org, acm@muc.de
> > From: Alan Mackenzie <acm@muc.de>
> > > Which is why we also have "pr".
> > OK, but that doesn't help with the annoyance in xpr and friends.
> > Anybody typing an expression with spaces into xpr can continue to use
> > print followed by xpr without arguments. For the usual case, when
> > there's exactly one argument, my patch resolves the annoyance. It now
> > handles the $argc > 1 case as an error.
> > So, why not install this patch in master, now?
> I don't like it, sorry. It is not clean enough, and it goes against
> the overall consistency of the commands we have in src/.gdbinit.
That's a shame. We should be able to do better with this sort of thing.
> You can always have any commands you want in your own ~/.gdbinit.
Yes, but that doesn't help other people. I'm closing the bug as won't
fix.
I'll also commit a fix for that other bug I mentioned earlier.
--
Alan Mackenzie (Nuremberg, Germany).
--- End Message ---