i965/fs: Short-circuit a loop in live variable analysis.

This has no functional effect, but should make subsequent changes a
little simpler.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Eric Anholt <eric@anholt.net>
i965/fs: Rename num_vars to num_vgrfs in live interval analysis.

num_vars was shorthand for the number of virtual GRFs.  num_vgrfs is a
bit clearer.  Plus, the next patch will introduce "vars" which are
distinct from vgrfs.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Eric Anholt <eric@anholt.net>
i965/fs: Do live variables dataflow analysis on a per-channel level.

This significantly improves our handling of VGRFs of size > 1.

Previously, we only marked VGRFs as def'd if the whole register was
written by a single instruction.  Large VGRFs which were written
piecemeal would not be considered def'd at all, even if they were
ultimately completely written.

Without being def'd, these were then marked "live in" to the basic
block, often extending the range to preceding blocks and sometimes
even the start of the program.

The new per-component tracking gives more accurate live intervals,
which makes register coalescing more effective.

In the future, this should help with texturing from GRFs on Gen7+.
A sampler message might be represented by a 2-register VGRF which
holds the texture coordinates.  If those are incoming varyings,
they'll be produced by two PLN instructions, which are piecemeal writes.

No reduction in shader-db instruction counts.  However, code which
prints the live interval ranges does show that some VGRFs now have
smaller (and more correct) live intervals.

v2: Rebase on current send-from-GRF code requiring adding extra use[]s.
v3: Rebase on live intervals fix to include defs in the end of the
    interval.
v4 (Kenneth Graunke): Rebase; split off a few preparatory patches;
    add lots of comments; minor style changes; rewrite commit message.
v5 (Eric Anholt): whitespace nit.

Written-by: Eric Anholt <eric@anholt.net> [v1-3]
Signed-off-by: Kenneth Graunke <kenneth@whitecape.org> [v4]
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Eric Anholt <eric@anholt.net> (v4)
i965/fs: Create a helper function for invalidating live intervals.

For now, this simply sets live_intervals_valid = false, but in the
future it will do something more sophisticated.

Based on a patch by Eric Anholt.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Eric Anholt <eric@anholt.net>
i965/fs: Factor def[]/use[] setup out to a separate function.

These blocks are about to grow some more code, and the indentation was
getting out of hand.

v2 (Kenneth Graunke): Rebase, minor typo fixes and style changes.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
i965/fs: Track live variable ranges on a per-channel level.

This is the information we'll actually use to replace the
virtual_grf_start[]/end[] arrays.

No change in shader-db.

v2 (Kenneth Graunke): Rebase; minor comment updates.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
i965/fs: Remove start/end aliases in compute_live_intervals().

In compute_live_intervals(), start and end are shorter names for
the virtual_grf_start and virtual_grf_end class members.

Now that the fs_live_intervals class has arrays named start and end
which are indexed by var, rather than VGRF, reusing the name is
confusing.  Plus, most of the code has been factored out, so using the
long names isn't as inconvenient.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Eric Anholt <eric@anholt.net>
i965/fs: Invalidate live intervals when compacting; don't fix them.

When compacting the list of VGRFs, we patch up the live interval ranges
(which are indexed by VGRF number).  Unfortunately, once we make
per-component data available, this will become too complicated to
maintain.  Instead, simply invalidate them.

This was pulled out of a patch by Eric Anholt.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Eric Anholt <eric@anholt.net>
i965/fs: Keep a copy of the live variables class around.

Now optimization passes will be able to look at the per-channel ranges.

v2: Rebase on various optimization pass changes.
v3 (Kenneth Graunke): Rename live_variables to live_intervals; split
   introduction of invalidate_live_intervals() into a separate patch.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
i965/fs: Use the new per-channel live ranges for dead code elimination.

v2 (Kenneth Graunke): Rebase on s/live_variables/live_intervals/g.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
i965/fs: Use per-channel interference for register_coalesce_2().

This will let us coalesce into texture-from-GRF arguments, which would
otherwise be prevented due to the live interval for the whole vgrf
extending across all the MOVs setting up the channels of the message

v2 (Kenneth Graunke): Rebase for renames.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
i965/fs: Allocate more register classes on gen7.

For texturing from GRFs, we now have payloads of arbitrary sizes up to the
message length limit.

v2 (Kenneth Graunke): Rebase on intel_context -> brw_context change.
v3: Add some comment text.
v4: Change some magic 16s to BRW_MAX_MRF (noted by Ken).  Leave the 11,
    which is the magic "max sampler message length".  BRW_MAX_MRF sizing
    on the little int arrays is retained because I could see us needing to
    extend in the future if we move to GRFs for FB writes (those go to at
    least 12 long in a quick scan of the specs)

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org> (v2)
Acked-by: Matt Turner <mattst88@gmail.com>
i965/fs: Convert gen7 to using GRFs for texture messages.

Looking at Lightsmark's shaders, the way we used MRFs (or in gen7's
case, GRFs) was bad in a couple of ways.  One was that it prevented
compute-to-MRF for the common case of a texcoord that gets used
exactly once, but where the texcoord setup all gets emitted before the
texture calls (such as when it's a bare fragment shader input, which
gets interpolated before processing main()).  Another was that it
introduced a bunch of dependencies that constrained scheduling, and
forced waits for texture operations to be done before they are
required.  For example, we can now move the compute-to-MRF
interpolation for the second texture send down after the first send.

The downside is that this generally prevents
remove_duplicate_mrf_writes() from doing anything, whereas previously
it avoided work for the case of sampling from the same texcoord twice.
However, I suspect that most of the win that originally justified that
code was in avoiding the WAR stall on the first send, which this patch
also avoids, rather than the small cost of the extra instruction.  We
see instruction count regressions in shaders in unigine, yofrankie,
savage2, hon, and gstreamer.

Improves GLB2.7 performance by 0.633628% +/- 0.491809% (n=121/125, avg of
~66fps, outliers below 61 dropped).

Improves openarena performance by 1.01092% +/- 0.66897% (n=425).

No significant difference on Lightsmark (n=44).

v2: Squash in the fix for register unspilling for send-from-GRF, fixing a
    segfault in lightsmark.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Acked-by: Matt Turner <mattst88@gmail.com>
dri: Remove dead comment.

The code it was referencing was removed in 2010.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
dri: Add an explanatory comment for an important driver entrypoint.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
dri: Merge drisw_util.c into dri_util.c

The only important difference was not calling drmGetVersion, and making
the swrast extension vtable.  That doesn't justify duplicating the other
330 lines of code.

v2: fix the scons build (code by Emil Velikov)
v3: fix scons build with swrast-only (code by Emil Velikov)
v4: Drop the new define I added, when we already have __NOT_HAVE_DRM_H.

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
dri: Move API version validation into dri/common.

i965, i915, radeon, r200, swrast, and nouveau were mostly trying to do the
same logic, except where they failed to.  Notably, swrast had code that
appeared to try to enable GLES1/2 but forgot to set api_mask (thus
preventing any gles context from being created), and the non-intel drivers
didn't support MESA_GL_VERSION_OVERRIDE.

nouveau still relies on _mesa_compute_version(), because I don't know what
its limits actually are, and gallium drivers don't declare limits up front
at all.  I think I've heard talk about doing so, though.

v2: Compat max version should be 30 (noted by Ken)
    Drop r100's custom max version check, too (noted by Emil Velikov)

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
intel: Remove silly check for !bufmgr.

If bufmgr didn't get created, then screen creation failed, and we never
should have got here in the first place.  This was added by Chris Wilson
in 2010 with no explanation for why it would be needed.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
i965: Clean up error handling for context creation.

The intel_screen.c used to be a dispatch to one of 3 driver functions, but
was down to 1, so it was kind of a waste.  In addition, it was trying to
free all of the data that might have been partially freed in the kernel
3.6 check (which comes after intelInitContext, and thus might have had
driverPrivate set and result in intelDestroyContext() doing work on the
freed data).  By moving the driverPrivate setup earlier, we can use
intelDestroyContext() consistently and avoid such problems in the future.

v2: Adjust the prototype of brwCreateContext to use the proper enum
    (fixing a compiler warning in some builds)

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org> (v1)
dri: Reference the global driver vtable once at screen init..

This is part of the prep for megadrivers, which won't allow using a single
global symbol due to the fact that there will be multiple drivers built
into the same dri.so file.  For that, we'll need screen init to take a
reference to the driver to set up this vtable.

v2: Fix two missed references to driDriverAPI.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org> (v1)