Merge the lp-surface-tiling branch into master.

Merge the lp-surface-tiling branch into master.

This branch implemented dual representations of texture/drawing surfaces:
one in the conventional linear layout and the other the tiled layout which
is used by the fragment shader pipe.  Per-tile flags indicate the layout
of each image tile.  In many situations this lets us avoid converting
image data between the two layouts.

Squashed commit of the following:

commit 563a7e3cc552fdcfcaf9ac0d4b1683c3ba2ae732
Author: Brian Paul <brianp@vmware.com>
Date:   Thu Apr 8 14:48:21 2010 -0600

    llvmpipe: convert points/lines to triangles with draw module

    This isn't the most efficient way to render points/lines but it allows us
    to run more tests.

commit a8aa763e8a717533f2b13bb6ea53cbccbede68c9
Author: Brian Paul <brianp@vmware.com>
Date:   Thu Apr 8 14:47:28 2010 -0600

    llvmpipe: call llvmpipe_get_texture_tile() for depth/stencil

    The returned pointer isn't used, but the tile status/layout info
    gets updated.  Helps to fix glReadPixels(DEPTH / STENCIL).

commit 463bc64af266194acbea71cd52e26a79b8c8a260
Author: Brian Paul <brianp@vmware.com>
Date:   Thu Apr 8 10:58:48 2010 -0600

    llvmpipe: add store_color to debug cmd_names list

commit 784cc73fb334a9d7b7c93cbd8a1445cdf742ff58
Author: Brian Paul <brianp@vmware.com>
Date:   Thu Apr 8 10:57:43 2010 -0600

    llvmpipe: fix debug build

commit 792c93171ec075664f55720ffed397ac2834a4fc
Author: Brian Paul <brianp@vmware.com>
Date:   Thu Apr 8 10:49:01 2010 -0600

    llvmpipe: fix cube mapping

commit 882b1035db88c3dd8aebe28dc971ac30a9ee39e3
Author: Brian Paul <brianp@vmware.com>
Date:   Thu Apr 8 09:53:30 2010 -0600

    llvmpipe: remove some older/unused code

commit b807d32b23145301e8842824664d9f06b9c5502e
Author: Brian Paul <brianp@vmware.com>
Date:   Thu Apr 8 09:29:50 2010 -0600

    llvmpipe: silence warning

commit 7b337e64fec92836ccdf9d96216289dd58418e35
Author: Brian Paul <brianp@vmware.com>
Date:   Wed Apr 7 17:06:08 2010 -0600

    llvmpipe: clean-up, comments in lp_surface_copy()

commit c52fa36f249cc652fa8d5fdd94d6574127c08c41
Author: Brian Paul <brianp@vmware.com>
Date:   Wed Apr 7 16:51:42 2010 -0600

    llvmpipe: overhaul tiled/linear memory management

    Now we keep per-tile layout info (linear vs. tiled (or neither or both)
    and convert from one layout to the other on demand.

commit 4a50ccfd470547c9be0704005818a87014e9c0e9
Author: Brian Paul <brianp@vmware.com>
Date:   Wed Apr 7 16:51:27 2010 -0600

    llvmpipe: added tile read/write counters

commit b7d0ea9c687ac8773b083791623826fa604adf21
Author: Brian Paul <brianp@vmware.com>
Date:   Mon Apr 5 14:54:04 2010 -0600

    llvmpipe: rename some functions

commit ee45c6e5b95cbd3c8cccc9aa4d45d8aef11e20c4
Author: Brian Paul <brianp@vmware.com>
Date:   Mon Apr 5 14:42:15 2010 -0600

    llvmpipe: re-org some get block/tile pointer code

commit 26ce97c16c0b6520ff1538803baa772d8c3b1280
Author: Brian Paul <brianp@vmware.com>
Date:   Mon Apr 5 14:34:13 2010 -0600

    llvmpipe: disable bad assertions

commit 5c670481248c4d46f87f13bf3af5655925e7002d
Author: Brian Paul <brianp@vmware.com>
Date:   Fri Apr 2 16:36:11 2010 -0600

    llvmpipe: add a special-case optimization to lp_surface_copy()

    Be more efficient when copying tiled image to linear image.
    Before, the fallback path was always converting the whole source image
    to linear.  Now we can convert just a sub region.

commit faa684645e64d6024b3a11e4e08da825e8220b2e
Author: Brian Paul <brianp@vmware.com>
Date:   Fri Apr 2 16:15:16 2010 -0600

    llvmpipe: assorted texture and tile/line conversion code change s

    The tiled/linear conversion functions take x/y positions now to
    allow converting only sub-regions.

    More texture-related helper functions.

commit baad81ec5318d44bfac1e37c7643afc0836607bb
Author: Brian Paul <brianp@vmware.com>
Date:   Tue Mar 30 13:18:40 2010 -0600

    llvmpipe: convert tiled->linear upon PIPE_FLUSH_SWAPBUFFERS

    If we know we're about to do a swapbuffers we should immediately
    convert the tiled color tiles to linear instead of later in
    llvmpipe_texture_unmap() since we can take advantage of threading/
    parallelism here.

commit 928dd41256811daeddb7506a49a34dbad04beaf8
Author: Brian Paul <brianp@vmware.com>
Date:   Tue Mar 30 09:16:58 2010 -0600

    llvmpipe: polish-up the llvmpipe_flush() code

commit dd6014abcf86c517d159b8175e0eaeb167ea2ef6
Author: Brian Paul <brianp@vmware.com>
Date:   Tue Mar 30 09:15:17 2010 -0600

    llvmpipe: SETUP_x enum clean-up

commit 0b1ce6da2b28a41f3389685ab93e10b43c950f5d
Author: Brian Paul <brianp@vmware.com>
Date:   Fri Mar 26 10:43:37 2010 -0600

    llvmpipe: remove unused vars

commit 4562663480f88162ed4452cb05569eecb67f9f39
Author: Brian Paul <brianp@vmware.com>
Date:   Fri Mar 26 10:31:55 2010 -0600

    llvmpipe: cope with non-existant color/depth buffers

    The fragment jit functions always grab these pointers, even if they're
    not used.

commit df4329edbaf204ed501f1eac0698b8198178f9af
Author: Brian Paul <brianp@vmware.com>
Date:   Thu Mar 25 15:20:15 2010 -0600

    llvmpipe: do all render target surface mapping/unmapping in the rast code

commit 3d0c25d5ba8b8f61e8366d4c97324e45d526ff41
Author: Brian Paul <brianp@vmware.com>
Date:   Thu Mar 25 14:31:21 2010 -0600

    llvmpipe: map z/stencil buffer on demand like color buffers

    Plus lots of code clean-up and loose ends taken care of.

commit c3b6fddd788aef09b4b84b843b7b1272231151e8
Author: Brian Paul <brianp@vmware.com>
Date:   Thu Mar 25 13:15:03 2010 -0600

    llvmpipe: remove unused write_zstencil field

commit 63374d97836926a6357e9d6dd24a509a8e155c56
Author: Brian Paul <brianp@vmware.com>
Date:   Thu Mar 25 09:45:59 2010 -0600

    llvmpipe: add missing lp_rast_end() call

    Fixes crash on window resize when LP_NUM_THREADS=0.

commit 92fe9952161cc06f6edc58778e9e5a8b9ea447dc
Author: Brian Paul <brianp@vmware.com>
Date:   Wed Mar 24 10:15:19 2010 -0600

    llvmpipe: add tiled/linear conversion for 16-bit Z images

commit 6605fa28c147f30df351da0e4413cab33e4db5da
Author: Brian Paul <brianp@vmware.com>
Date:   Tue Mar 23 16:06:41 2010 -0600

    llvmpipe: implement tiled/linear conversion for Z/stencil images

commit 804528d84ffa292ef9d49d3666cdd3fa099ff3ff
Author: Brian Paul <brianp@vmware.com>
Date:   Tue Mar 23 16:05:45 2010 -0600

    llvmpipe: added texture stride comment

commit 66a88c012edf670c4ac887a912f02dcff93266dd
Author: Brian Paul <brianp@vmware.com>
Date:   Tue Mar 23 16:04:07 2010 -0600

    llvmpipe: remove unused vars

commit e2ca8d1328316dc8b36d5f688c16d109e49a6870
Author: Brian Paul <brianp@vmware.com>
Date:   Mon Mar 22 18:53:11 2010 -0600

    llvmpipe: checkpoint WIP: overhaul texture/surface mapping

    Conversion between tiled and linear surfaces is working everywhere now.
    The LP_TEXTURE_READ/READ_WRITE/WRITE_ALL flags let us avoid unnecessary
    image layout conversions.

    Still some loose ends, temporary/debug code, etc.
    Need to implement tiled/linear conversion for depth/stencil images.

commit f2730a03839ee8984c1f537b7cbebba24961397a
Author: Brian Paul <brianp@vmware.com>
Date:   Mon Mar 22 14:41:58 2010 -0600

    llvmpipe: rename/repurpose lp_rast_store_color()

commit e192a47552c5d20d2caef452ca7697e2cd852c9b
Author: Brian Paul <brianp@vmware.com>
Date:   Mon Mar 22 14:38:51 2010 -0600

    llvmpipe: remove lp_rast_load_color()

commit 3cff0bde4b4ab980e1c3e812700419091527c76b
Author: Brian Paul <brianp@vmware.com>
Date:   Mon Mar 22 14:11:38 2010 -0600

    llvmpipe: remove/consolidate texture image code

commit 3a2f08b6a550c69ef5e874f482be30252cbf8bfa
Author: Brian Paul <brianp@vmware.com>
Date:   Fri Mar 19 17:03:14 2010 -0600

    llvmpipe: checkpoint WIP: directly render to tiled texture buffers

    We're now directly writing colors into the tiled texture image buffers.

    This is a checkpoint commit with lots of dead code and temporary hacks.
    Everything will get cleaned up eventually.

commit c5ca987e03870849514d4e3c99af143722a09695
Author: Brian Paul <brianp@vmware.com>
Date:   Fri Mar 19 16:41:14 2010 -0600

    llvmpipe: refactor code, create tile_pixel_offset()

commit 2133e8273e937cbac09cd7264d6ce53af9764ddb
Author: Brian Paul <brianp@vmware.com>
Date:   Fri Mar 19 14:55:11 2010 -0600

    llvmpipe: pass LP_TEXTURE_LINEAR/TILED flags around

commit b9b9d4b82b01f4588721fdc8444740f859b4a021
Author: Brian Paul <brianp@vmware.com>
Date:   Fri Mar 19 14:51:05 2010 -0600

    llvmpipe: checkpoint WIP: hanlde co-existing tiled/linear texture data

    Cube maps are temporarily broken, maybe other things.

commit 4cd322e6889940b5f155fcb69041b685b9ef9273
Author: Brian Paul <brianp@vmware.com>
Date:   Fri Mar 19 11:34:43 2010 -0600

    progs/demos: add other modes/patterns to dissolve demo