[PATCH V3] fixed inherit_abstract_dies infinite recursive call

[Doug Evans]

On Tue, Jan 21, 2014 at 7:44 PM,  <manjian2006@gmail.com> wrote:
> From: linzj <linzj@ucweb.com>
>
>     Reset the die's in_process bit using cleanup facility.

Cool, thanks.

A couple more nits inline.
[apologies. gdb's coding standards are that pedantic,
which in some sense is a good thing - the consistency
tends to make adhering to them easier to achieve]

btw, do you have a copyright assignment on file?
This change feels small enough to me to not need one,
but it's not clear.

>>>    ChangeLog added.
>>>    Please Joel Brobecker <brobecker@adacore.com> helps with the testcases.
>>> >>     The c++ code causing the problem is:
>>> >>
>>> >>         // Integer variants of certain metrics, used for HTML rendering.
>>> >>         int ascent(FontBaseline baselineType = AlphabeticBaseline) const
>>> >>         {
>>> >>             if (baselineType == AlphabeticBaseline)
>>> >>                 return lroundf(m_ascent);
>>> >>             return height() - height() / 2;
>>> >>         }
>>> >>
>>> >>         int height(FontBaseline baselineType = AlphabeticBaseline) const
>>> >>         {
>>> >>             return ascent(baselineType) + descent(baselineType);
>>> >>         }
>>> >>
>>> >>     As you can see,ascent(0x5816d55) calls height(0x5812c1b),and height calls
>>> >>     ascent(0x5816d55) recursivly.And the compiler  generates these dwarf code
>>> >>     representing this relationship preciously.
>>> >>
>>> >>     A dwarf die may have the following relationship:
>>> >>     564860c<-----------------------------
>>> >>       |                                 |
>>> >>       |(abstract origin)                |
>>> >>       |                                 |
>>> >>       V                                 |
>>> >>     5816d55                             | (abstract origin)
>>> >>       |                                 |
>>> >>       |(child)                          |
>>> >>       |                                 |
>>> >>       V                                 |
>>> >>       ...                               |
>>> >>     5812c34------------------------------
>>> >>     So inherit_abstract_dies may results in infinite recursive call.
>>> >>     A bit field call in_process has been add to struct die_info to fix this problem.
>>> >>     process_die would first check if a die is in processing state, if so,just return.
>>> >>     Then in_process bit is set.Before process_die returns,this bit field is unset.
> ---
>  ChangeLog        |  8 ++++++++
>  gdb/dwarf2read.c | 19 +++++++++++++++++++
>  2 files changed, 27 insertions(+)
>
> diff --git a/ChangeLog b/ChangeLog
> index 9b1cbfa..c17af8d 100644
> --- a/ChangeLog
> +++ b/ChangeLog
> @@ -1,3 +1,11 @@
> +2013-01-20  lin Zuojian  <manjian2006@gmail.com>
> +       * gdb/dwarf2read.c(struct die_info): Add a
> +       bit to form a bitmap to avoid visit twice
> +       when process_die.
> +       * gdb/dwarf2read.c(process_die): Test in_process
> +       bit to avoid visit twice.Set in_process bit
> +       before doing actual jobs.Unset in_process bit
> +       before process_die returns.

1) Don't include the diff to the ChangeLog, cut-n-paste the text as is
to the top of the patch in the email submission.

2) Don't preface file names with gdb/ in the ChangeLog.

If the patch involves changes to files in other directories
for which gdb's ChangeLog file is the correct one to use,
*then* include the directory.  E.g., common/queue.h.

If the patch involves changes to files in other directories
that have their own ChangeLog file, then write the
ChangeLog entry in the email as, e.g.,

        testsuite/
        * lib/gdb.exp (foo): mumble.

But remove the line with "testsuite/" when committing the change.

3) Don't repeat the file name within one ChangeLog entry.

[well, for some particularly complex entries it could
be useful, but not in general]

4) You don't need to explain the change in the changelog
entry, just state what was changed.

5) Blank line after the date/name line.

6) Use the tab character to indent each line.

7) Space after the file name.

Combining all of that yields:
[assuming cut-n-paste preserved the tabs]

2013-01-20  lin Zuojian  <manjian2006@gmail.com>

        * dwarf2read.c (struct die_info): New member in_process.
        (reset_die_in_process): New function.
        (process_die): Set it at the start, reset when returning.

Most of these rules should be self-evident from
reading existing entries, but I can understand
there still being some indecision as to "what's right".

>  2013-12-19  Keven Boell  <keven.boell@intel.com>
>
>         * cp-namespace.c (cp_lookup_nested_symbol): Enable
> diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c
> index 7ca527d..cf27283 100644
> --- a/gdb/dwarf2read.c
> +++ b/gdb/dwarf2read.c
> @@ -1224,6 +1224,8 @@ struct die_info
>      /* True if we're presently building the full type name for the
>         type derived from this DIE.  */
>      unsigned char building_fullname : 1;

It would be consistent with the rest of the definition of
this struct to have a blank line here
(though I realize it's a bit of a toss up).

> +    /* True if this die is in process.  */
> +    unsigned char in_process : 1;
>
>      /* Abbrev number */
>      unsigned int abbrev;
> @@ -8008,11 +8010,27 @@ process_imported_unit_die (struct die_info *die, struct dwarf2_cu *cu)
>      }
>  }
>
> +/* Reset the in_process bit of a die.  */

Blank line between the comment describing the function
and its definition.

> +static void
> +reset_die_in_process(void *arg)

Space before (.

> +{
> +  struct die_info *die = arg;
> +  die->in_process = 0;
> +}
> +
>  /* Process a die and its children.  */
>
>  static void
>  process_die (struct die_info *die, struct dwarf2_cu *cu)
>  {
> +  /* The in process bit of a die's cleanup.  */
> +  struct cleanup * in_process;

No space after *.

I'm ambivalent on keeping the comment.
I could see deleting it, but if you want
to keep it it's fine with me.

> +
> +  /* Only process those who are not in process.  */

English wasn't my best subject in school, but this reads
better to me:

  /* Only process those not already in process.  */

> +  if (die->in_process)
> +    return;
> +  die->in_process = 1;
> +  in_process = make_cleanup(reset_die_in_process,die);

Space before (.

>    switch (die->tag)
>      {
>      case DW_TAG_padding:
> @@ -8100,6 +8118,7 @@ process_die (struct die_info *die, struct dwarf2_cu *cu)
>        new_symbol (die, NULL, cu);
>        break;
>      }
> +    do_cleanups(in_process);

Space before (.

>  }
>
>  /* DWARF name computation.  */
> --
> 1.8.3.2
>


I realize it's a pain to fix all these nits even before the actual
core of the patch has been accepted.

It's fine with me, but I would wait a bit to see if
others have any comments.