Re: [patch rfc] Eliminate extract_address

[Kevin Buettner <kevinb at redhat dot com>]

On May 15, 12:49pm, Andrew Cagney wrote:

> > First, the return types are different.  extract_address() returns
> > CORE_ADDR while extract_unsigned_integer returns ULONGEST.  If
> > we were to encounter a scenario where this is a problem, it's easier
> > to fix a wrapper (extract_address()) instead of the myriad places in
> > the code which presently call extract_address().  (This point is
> > probably moot because I suspect we already have a lot of code which
> > assumes that CORE_ADDR may be interchanged with LONGEST or ULONGEST
> > anyway.)
> 
> sizeof(CORE_ADDR) <= sizeof(ULONGEST) so this isn't a problem.

Do we have a gdb_assert() somewhere to ensure that this is the case?
(This could happen at initialization time...)

> > Second, having function calls to extract_address() provides
> > information to the reader that you don't get by having calls to
> > extract_unsigned_integer().  It tells the reader that we're expecting
> > to get an address and not an integer.  This really helps when someone
> > reading gdb's code is wondering about what the thing is that's being
> > extracted.
> 
> The extract_address function doesn't extract an address, it extracts an 
> unsigned integer.
> On the MIPS, extract_address needs to sign extend.  On the d10v, extract 
> address needs to know the address space.

Yes, I understand that.  Doing the substitution you propose will make
it more difficult to make the correct fix (of using extract_typed_address)
at a later time.

> If the code needs to extract an address it can use extract_typed_address 
> which corectly handles all these cases.

Yes.

> Is it a good thing?  It eliminates a lie.

At the expense of making the code marginally less comprehensible and
making it more difficult to identify the potential cases where
extract_typed_address() should be used instead.

Or have all of those cases already been identified?  If so, then I
withdraw my objection.  (Though I still like having "address" in the
function name to help to document what it is that's being extracted.)

Kevin