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Re: [PATCH PR c++/17132] Add new argument NOSIDE to find_overload_match
- From: Siva Chandra <sivachandra at google dot com>
- To: gdb-patches <gdb-patches at sourceware dot org>
- Date: Wed, 16 Jul 2014 06:34:16 -0700
- Subject: Re: [PATCH PR c++/17132] Add new argument NOSIDE to find_overload_match
- Authentication-results: sourceware.org; auth=none
- References: <CAGyQ6gwjpbYWoT7xki0tNQF7vq9mA_d+zMrnCDxXGUbU6gn1=A at mail dot gmail dot com>
On Wed, Jul 9, 2014 at 11:52 AM, Siva Chandra <firstname.lastname@example.org> wrote:
> The bug with examples where it manifests is detailed on the bug page.
> To summarize here:
> When expressions involving calls to virtual methods are evaluated
> under EVAL_AVOID_SIDE_EFFECTS, the intermediate objects could be
> zeroed values. In which case, when find_overload_match tries to
> (indirectly) lookup the method for the most derived type of the object
> via its vptr, GDB trips with "Cannot access memory at address 0x0."
> This patch adds an additional argument NOSIDE to find_overload_match
> which serves as a flag to indicate whether method resolution should be
> performed by looking up the most derived object via the vptr. When
> NOSIDE is EVAL_AVOID_SIDE_EFFECTS, the method for the compile time
> type (instead of the most derived type) of the object is returned by
> find_overload_match. This will not affect the functionality as all
> that is important when evaluating under EVAL_AVOID_SIDE_EFFECTS is the
> return type of the method.
> Regression tested testsuite/gdb.cp. But, am I simplifying the problem somewhere?
> 2014-07-09 Siva Chandra Reddy <email@example.com>
> * eval.c: Update all calls to find_overload_match.
> * valarith.c: Update calls to find_overload_match.
> (value_user_defined_cpp_op, value_user_defined_op): New
> argument NOSIDE. Update all callers.
> * valops.c (find_overload_match): New argument NOSIDE.
> * value.h (find_overload_match): Update signature.
> * gdb.cp/pr17132.cc: New file.
> * gdb.cp/pr17132.exp: New file.