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gdb: remove unnecessary code relating to limited-length arrays

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While reviewing this commit:

  commit 8fdd2b2bcd
  Date:   Tue Aug 6 19:34:18 2024 +0200

      Mark unavailable bytes of limited-length arrays when allocating contents

I spotted that there was some code in value::record_latest relating to
limited-length arrays which appeared redundant.  The code was added
with the first introduction on limited-length arrays in commit:

  commit a0c0791577
  Date:   Fri Feb 10 23:49:19 2023 +0000

      GDB: Introduce limited array lengths while printing values

The code in question is in value::record_latest.  When the value being
recorded is lazy we need to fetch its value before adding it to the
history list.  The code I spotted checks to see if the value is lazy,
if we currently have array limiting in effect, and if we do sets
m_limited_length to max_value_size before finally calling fetch_lazy.

The first thing fetch_lazy does is call allocate_contents to setup the
value's buffer, and in allocate_contents we perform the same set of
checks: if the value is an array, and array length limiting is in
effect then only allocate max_value_size buffer for the contents.

In ::allocate_contents the `if` condition check is spread out between
::allocate_contents and ::set_limited_array_length, but I'm certain
it's checking the same condition.

As such the checks and m_limited_length adjustment in ::record_latest
is redundant and can be removed.

Out of curiosity I went back to the original a0c0791577 commit
and removed the same block of code from record_latest_value (as
value::record_latest was called back then) and non of the tests added
by commit a0c0791577 failed.  I think this block of code was
never needed.

Anyway, I removed the unnecessary code and retested and there are no
regressions.

There should be no user visible changes after this commit.

Approved-By: John Baldwin <jhb@FreeBSD.org>
This commit is contained in:
Andrew Burgess 2024-08-06 20:53:35 +01:00
parent ca25db0641
commit a4c88987f0
1 changed files with 1 additions and 15 deletions
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16
gdb/value.c
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@ -1700,21 +1700,7 @@ value::record_latest ()
the value was taken, and fast watchpoints should be able to assume that
a value on the value history never changes. */
if (lazy ())
{
/* We know that this is a _huge_ array, any attempt to fetch this
is going to cause GDB to throw an error. However, to allow
the array to still be displayed we fetch its contents up to
`max_value_size' and mark anything beyond "unavailable" in
the history. */
if (m_type->code () == TYPE_CODE_ARRAY
&& m_type->length () > max_value_size
&& array_length_limiting_element_count.has_value ()
&& m_enclosing_type == m_type
&& calculate_limited_array_length (m_type) <= max_value_size)
m_limited_length = max_value_size;
fetch_lazy ();
}
fetch_lazy ();
/* Mark the value as recorded in the history for the availability check. */
m_in_history = true;