Re: [PATCH] gdb: fix handling of DW_AT_entry_pc of inlined subroutines

[Tom Tromey <tom@tromey.com>]

>>>>> "Andrew" == Andrew Burgess <aburgess@redhat.com> writes:

Andrew> This commit extends the block class to carry the entry PC as a
Andrew> separate member variable.  Then the DWARF reader is extended to read
Andrew> and set the entry PC for the block.  Now in block::entry_pc(), if the
Andrew> entry PC has been set to a specific value, this is the value returned.

I wonder what the size cost is of adding a field to block -- I mean the
overall cost, not just sizeof(block).

But I suppose in the end it's not very important, since we normally
operate on the assumption that most CUs won't be expanded.

Andrew>    CORE_ADDR entry_pc () const
Andrew>    {
Andrew> -    if (this->is_contiguous ())
Andrew> +    if (m_entry_pc.has_value ())
Andrew> +      return *m_entry_pc;
Andrew> +    else if (this->is_contiguous ())
Andrew>        return this->start ();
Andrew>      else
Andrew>        return this->ranges ()[0].start ();

Andrew> +
Andrew> +  /* If set this is the entry PC for the block.  */
Andrew> +
Andrew> +  std::optional<CORE_ADDR> m_entry_pc;
Andrew>  };

std::optional here means carrying an extra word for just the flag bit.

However I wonder if it would work to use CORE_ADDR here and use 0 as a
sentinel to mean unset; or some other scheme making it so the entry PC
and the 'start' are identical by default.

Tom