On 01/22/2011 10:48 AM, Sergei Trofimovich wrote:
> I've attached dirty patch. It has not very nice comments, tabs and spaces yet.
Steve perhaps should weigh in here...
> As I understand, TARGET_AUTO_PIC, TARGET_CONSTANT_GP,
> TARGET_NO_PIC should somehow fall into different memory models.
> I don't get exact difference between them.
Yes, auto-pic and constant-gp are slightly different, but ...
> i386 distincts code models in a more fine grained manner:
> CMODEL_* and CMODEL_*_PIC. Maybe, ia64 should have similar distinction?
With
SMALL_PIC, // 21-bit call offsets, 21-bit gp offsets
MEDIUM, // 21-bit call offsets, 64-bit absolute data
MEDIUM_PIC, // 21-bit call offsets, 64-bit gp offsets
LARGE, // 64-bit call offsets, 64-bit absolute data
LARGE_PIC, // 64-bit call offsets, 64-bit gp offsets
(no non-pic small), then -mno-pic can be absorbed as MEDIUM. The
auto-pic option is MEDIUM_PIC, but with a special bit of code in
the prologue to setup the gp register.
> AFAIU R_IA64_PCREL21B won't let us make calls more, than 2^21 bundles away.
> (~16 megabytes up and down).
> What kind of calls should be emitted in this case? call_gp/call_value_gp?
brl.call.sptk.many b0 = foo#
which is another X-format insn with a 64-bit offset.
r~
