On Oct 1, 2006, at 7:57 PM, Richard Kenner wrote:
It can't be normalized to BITS_PER_UNIT, but to DECL_OFFSET_ALIGN
since
we are asserting that DECL_FIELD_OFFSET is aligned to
DECL_OFFSET_ALIGN.
That doesn't make sense to me. It seems to me that we can
normalize it
however we please; ul
> > It can't be normalized to BITS_PER_UNIT, but to DECL_OFFSET_ALIGN since
> > we are asserting that DECL_FIELD_OFFSET is aligned to DECL_OFFSET_ALIGN.
>
> That doesn't make sense to me. It seems to me that we can normalize it
> however we please; ultimately, all these representations just give
Richard Kenner wrote:
That doesn't explain why the bit value isn't normalized to be smaller
than BITS_PER_UNIT; any whole bytes could be incorporated into the
variably sized offset.
It can't be normalized to BITS_PER_UNIT, but to DECL_OFFSET_ALIGN since
we are asserting that DECL_FIELD_OFFSET
> That doesn't explain why the bit value isn't normalized to be smaller
> than BITS_PER_UNIT; any whole bytes could be incorporated into the
> variably sized offset.
It can't be normalized to BITS_PER_UNIT, but to DECL_OFFSET_ALIGN since
we are asserting that DECL_FIELD_OFFSET is aligned to DECL
Richard Kenner wrote:
I don't follow. The current representation of variable-position fields uses
*both* fields, a variable offset in *bytes*, plus a constant offset in *bits*.
That doesn't explain why the bit value isn't normalized to be smaller
than BITS_PER_UNIT; any whole bytes could be
> Unique, but uncommon.
Right.
> Thus, it would make sense to make it a union with the other
> information with a discriminator. As a plus, you'd be able to tell
> variable offset fields by checking a single bit instead of a load
> (TREE_CODE ).
>
> IE
> unsigned int: offset_is_variable:1;
> un
On 9/28/06, Richard Kenner <[EMAIL PROTECTED]> wrote:
> The only trouble you'll probably run into is with fields whose offset
> from the start of a structure is variable.
Exactly. That's the reason it's defined the way it is. There is no way
to synthesize that field from any other in the FIELD
> The only trouble you'll probably run into is with fields whose offset
> from the start of a structure is variable.
Exactly. That's the reason it's defined the way it is. There is no way
to synthesize that field from any other in the FIELD_DECL in the most
general case: it is unique informati
Chris Lattner wrote:
Also, because of GCC's internal representation of integers, you have
to be careful that you have enough bits; for example, you need 72 bits
to represent things in a 64-bit address space.
Actually, just 67, right? Does GCC support structures whose size is
greater than 2^
Mark Mitchell wrote:
Are
you going through the stor_layout.c:place_field routines when creating
structure types? If so, I wouldn't; here, you know where stuff is
supposed to go, so I would just put it there, and set DECL_FIELD_OFFSET,
etc., accordingly.
No, I'm not using the fancy stor_lay
On Sep 28, 2006, at 1:58 PM, Mark Mitchell wrote:
Chris Lattner wrote:
An alternative design, which would save a field, is just to keep
the offset of a field, in bits, from the start of the structure.
Yes, that would also work. But, in many cases, you need the byte
offset, so there's a
Chris Lattner wrote:
An alternative design, which would save a field, is just to keep the
offset of a field, in bits, from the start of the structure.
Yes, that would also work. But, in many cases, you need the byte
offset, so there's a time/space tradeoff. Also, because of GCC's
internal
On Sep 28, 2006, at 1:43 PM, Mark Mitchell wrote:
Sandra Loosemore wrote:
I've been having a heck of a time figuring out how to translate
the offsets for struct fields from the DWARF encoding back to
GCC's internal encoding for the LTO project.
Yes, that's a nasty bit.
I think the DECL_FI
Sandra Loosemore wrote:
I've been having a heck of a time figuring out how to translate the
offsets for struct fields from the DWARF encoding back to GCC's internal
encoding for the LTO project.
Yes, that's a nasty bit.
I think the DECL_FIELD_OFFSET/DECL_FIELD_BIT_OFFSET stuff is, quite
sim
On Sep 27, 2006, at 7:04 PM, Sandra Loosemore wrote:
I've been having a heck of a time figuring out how to translate the
offsets for struct fields from the DWARF encoding back to GCC's
internal encoding for the LTO project. I've got a handle on the
DWARF encoding and how to do the necessa
15 matches
Mail list logo
