Re: [PATCH] printcmd.c (ui_printf): make internalvar string can be printf and eval when inferior cannot alloc memory

Hui Zhu
2011-08-14T15:10:13Z

On Fri, Jul 22, 2011 at 04:38, Tom Tromey <tromey@redhat.com> wrote:
>>>>>> ">" == Hui Zhu <teawater@gmail.com> writes:
>
>>> So I make a patch to handle the error from value_as_address.  If
>>> value_as_address get error and this is a internalvar, call
>>> value_contents to get the address of the val.
>
> I don't think this is the best approach to solve this problem.
>
> It seems to me that if the value is already an array, the data might
> already exist in gdb, and then you don't have to even try to coerce it
> to memory.  (However, for a pointer or integer value, using
> value_as_address is still the best thing.)
>
> I would suggest looking to see how valprint handles this situation, then
> do the same thing here.
>
> Tom
>

Hi Tom,

Thanks for your help.
I make a new patch according to your mail.

Best,
Hui

2011-08-14 Hui Zhu <teawater@gmail.com>

* printcmd.c (ui_printf): Add a handler for internalvar and
TYPE_CODE_ARRAY.
---
printcmd.c | 48 +++++++++++++++++++++++++++---------------------
1 file changed, 27 insertions(+), 21 deletions(-)

--- a/printcmd.c
+++ b/printcmd.c
@@ -2343,32 +2343,38 @@ ui_printf (char *arg, struct ui_file *st
switch (argclass[i])
{
case string_arg:
- {
- gdb_byte *str;
- CORE_ADDR tem;
- int j;
+ if (VALUE_LVAL (val_args[i]) == lval_internalvar
+ && TYPE_CODE (check_typedef (value_type (val_args[i])))
+ == TYPE_CODE_ARRAY)
+ fprintf_filtered (stream, current_substring,
+ (char *) value_contents (val_args[i]));
+ else
+ {
+ gdb_byte *str;
+ CORE_ADDR tem;
+ int j;

- tem = value_as_address (val_args[i]);
+ tem = value_as_address (val_args[i]);

- /* This is a %s argument. Find the length of the string. */
- for (j = 0;; j++)
- {
- gdb_byte c;
+ /* This is a %s argument. Find the length of the string. */
+ for (j = 0;; j++)
+ {
+ gdb_byte c;

- QUIT;
- read_memory (tem + j, &c, 1);
- if (c == 0)
- break;
- }
+ QUIT;
+ read_memory (tem + j, &c, 1);
+ if (c == 0)
+ break;
+ }

- /* Copy the string contents into a string inside GDB. */
- str = (gdb_byte *) alloca (j + 1);
- if (j != 0)
- read_memory (tem, str, j);
- str[j] = 0;
+ /* Copy the string contents into a string inside GDB. */
+ str = (gdb_byte *) alloca (j + 1);
+ if (j != 0)
+ read_memory (tem, str, j);
+ str[j] = 0;

- fprintf_filtered (stream, current_substring, (char *) str);
- }
+ fprintf_filtered (stream, current_substring, (char *) str);
+ }
break;
case wide_string_arg:
{