Re: [PATCH] Fix gdb crash when trying to print the address of a synthetic pointer.

[Pedro Alves <palves@redhat.com>]

Hi Martin,

On 04/07/2015 03:09 PM, Martin Galvan wrote:
> Trying to print the address of a synthetic pointer (such as a C++ reference after O3 optimization) will cause gdb to crash with the following message:
> 
> ../gdb/dwarf2loc.c:1625: internal-error: Should not be able to create a lazy value with an enclosing type
> 
> This patch fixes that by doing a check for synthetic pointers in value_addr and printing an error message.
> 
> I have a company-wide copyright assignment. I don't have commit access, though, so it would be great if anyone could commit this for me.
> 

Does this pass the testsuite?  I seem to recall that the
TYPE_CODE_REF path below is used by synthetic pointers, but
I could well be wrong.

Could you add some test to cover this?  We have some <synthetic
pointer> tests in gdb.dwarf2/implptr.exp.  Maybe add something there?

> gdb/
> 2015-04-07 Martin Galvan <martin.galvan@tallertechnologies.com>

Two spaces before and after name.

> 
> 	* valops.c (value_addr): Don't try to get the address of a synthetic pointer.

Please wrap this at 80 cols.

> 
> ---
>  gdb/valops.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/gdb/valops.c b/gdb/valops.c
> index 66c63c1..66e2c9d 100644
> --- a/gdb/valops.c
> +++ b/gdb/valops.c
> @@ -1474,6 +1474,13 @@ value_addr (struct value *arg1)
>    struct value *arg2;
>    struct type *type = check_typedef (value_type (arg1));
> 
> +  if (value_bits_synthetic_pointer(arg1, value_embedded_offset (arg1),

Missing space before parens.

> +      TARGET_CHAR_BIT * TYPE_LENGTH (type)))
> +    {
> +      error (_("Attempt to take address of a synthetic pointer."));
> +      return NULL;

This "return" is never reached, as "error" throws.  Please remove it,
and then remove the then unnecessary braces.

Thanks,
Pedro Alves