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Re: [PATCH] Fix gdb crash when trying to print the address of a synthetic pointer.
- From: Pedro Alves <palves at redhat dot com>
- To: Martin Galvan <martin dot galvan at tallertechnologies dot com>, gdb-patches at sourceware dot org
- Date: Tue, 07 Apr 2015 15:33:51 +0100
- Subject: Re: [PATCH] Fix gdb crash when trying to print the address of a synthetic pointer.
- Authentication-results: sourceware.org; auth=none
- References: <1428415783-15199-1-git-send-email-martin dot galvan at tallertechnologies dot 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