Mesa (master): softpipe: fix dangling references to shaders in the TGSI executor

[Brian Paul]

Module: Mesa
Branch: master
Commit: 1fce9d58cc70deaff284e1d9d0ffcb15b61e7595
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=1fce9d58cc70deaff284e1d9d0ffcb15b61e7595

Author: Brian Paul <brianp at vmware.com>
Date:   Thu May  6 15:10:51 2010 -0600

softpipe: fix dangling references to shaders in the TGSI executor

If a shader was bound to the fragment shader TGSI executor and it was
then deleted and a new shader was allocated at the same address as the
old shader, the new fragment shader would not get properly bound to
the TGSI machine and we'd wind up using the old one.

This would not have been a problem if shaders were refcounted.

Now the TGSI machine is owned by the context rather than the quad
pipeline's shader stage so that the softpipe_delete_fs_state()
function can access it.

Fixes sporadic failures of the piglit fp-long-alu test (fd.o bug 27989).

---

 src/gallium/drivers/softpipe/sp_context.c  |    5 +++++
 src/gallium/drivers/softpipe/sp_context.h  |    2 ++
 src/gallium/drivers/softpipe/sp_quad_fs.c  |   24 +++++-------------------
 src/gallium/drivers/softpipe/sp_state_fs.c |   11 ++++++++++-
 4 files changed, 22 insertions(+), 20 deletions(-)

diff --git a/src/gallium/drivers/softpipe/sp_context.c b/src/gallium/drivers/softpipe/sp_context.c
index f6e2b80..fea3520 100644
--- a/src/gallium/drivers/softpipe/sp_context.c
+++ b/src/gallium/drivers/softpipe/sp_context.c
@@ -36,6 +36,7 @@
 #include "util/u_math.h"
 #include "util/u_memory.h"
 #include "util/u_inlines.h"
+#include "tgsi/tgsi_exec.h"
 #include "sp_clear.h"
 #include "sp_context.h"
 #include "sp_flush.h"
@@ -123,6 +124,8 @@ softpipe_destroy( struct pipe_context *pipe )
       }
    }
 
+   tgsi_exec_machine_destroy(softpipe->fs_machine);
+
    FREE( softpipe );
 }
 
@@ -293,6 +296,8 @@ softpipe_create_context( struct pipe_screen *screen,
       softpipe->vertex_tex_cache[i] = sp_create_tex_tile_cache( &softpipe->pipe );
    }
 
+   softpipe->fs_machine = tgsi_exec_machine_create();
+
    /* setup quad rendering stages */
    softpipe->quad.shade = sp_quad_shade_stage(softpipe);
    softpipe->quad.depth_test = sp_quad_depth_test_stage(softpipe);
diff --git a/src/gallium/drivers/softpipe/sp_context.h b/src/gallium/drivers/softpipe/sp_context.h
index 9260787..aa69625 100644
--- a/src/gallium/drivers/softpipe/sp_context.h
+++ b/src/gallium/drivers/softpipe/sp_context.h
@@ -140,6 +140,8 @@ struct softpipe_context {
       struct sp_sampler_varient *frag_samplers_list[PIPE_MAX_SAMPLERS];
    } tgsi;
 
+   struct tgsi_exec_machine *fs_machine;
+
    /** The primitive drawing context */
    struct draw_context *draw;
 
diff --git a/src/gallium/drivers/softpipe/sp_quad_fs.c b/src/gallium/drivers/softpipe/sp_quad_fs.c
index 8ae5a7f..907e94b 100644
--- a/src/gallium/drivers/softpipe/sp_quad_fs.c
+++ b/src/gallium/drivers/softpipe/sp_quad_fs.c
@@ -50,8 +50,8 @@
 struct quad_shade_stage
 {
    struct quad_stage stage;  /**< base class */
-   struct tgsi_exec_machine *machine;
-   struct tgsi_exec_vector *inputs, *outputs;
+
+   /* no other fields at this time */
 };
 
 
@@ -70,9 +70,8 @@ quad_shade_stage(struct quad_stage *qs)
 static INLINE boolean
 shade_quad(struct quad_stage *qs, struct quad_header *quad)
 {
-   struct quad_shade_stage *qss = quad_shade_stage( qs );
    struct softpipe_context *softpipe = qs->softpipe;
-   struct tgsi_exec_machine *machine = qss->machine;
+   struct tgsi_exec_machine *machine = softpipe->fs_machine;
 
    /* run shader */
    return softpipe->fs->run( softpipe->fs, machine, quad );
@@ -108,9 +107,8 @@ shade_quads(struct quad_stage *qs,
             struct quad_header *quads[],
             unsigned nr)
 {
-   struct quad_shade_stage *qss = quad_shade_stage( qs );
    struct softpipe_context *softpipe = qs->softpipe;
-   struct tgsi_exec_machine *machine = qss->machine;
+   struct tgsi_exec_machine *machine = softpipe->fs_machine;
    unsigned i, pass = 0;
 
    for (i = 0; i < PIPE_MAX_CONSTANT_BUFFERS; i++) {
@@ -139,11 +137,10 @@ shade_quads(struct quad_stage *qs,
 static void
 shade_begin(struct quad_stage *qs)
 {
-   struct quad_shade_stage *qss = quad_shade_stage(qs);
    struct softpipe_context *softpipe = qs->softpipe;
 
    softpipe->fs->prepare( softpipe->fs, 
-			  qss->machine,
+			  softpipe->fs_machine,
 			  (struct tgsi_sampler **)
                              softpipe->tgsi.frag_samplers_list );
 
@@ -154,10 +151,6 @@ shade_begin(struct quad_stage *qs)
 static void
 shade_destroy(struct quad_stage *qs)
 {
-   struct quad_shade_stage *qss = (struct quad_shade_stage *) qs;
-
-   tgsi_exec_machine_destroy(qss->machine);
-
    FREE( qs );
 }
 
@@ -174,16 +167,9 @@ sp_quad_shade_stage( struct softpipe_context *softpipe )
    qss->stage.run = shade_quads;
    qss->stage.destroy = shade_destroy;
 
-   qss->machine = tgsi_exec_machine_create();
-   if (!qss->machine)
-      goto fail;
-
    return &qss->stage;
 
 fail:
-   if (qss && qss->machine)
-      tgsi_exec_machine_destroy(qss->machine);
-
    FREE(qss);
    return NULL;
 }
diff --git a/src/gallium/drivers/softpipe/sp_state_fs.c b/src/gallium/drivers/softpipe/sp_state_fs.c
index 7f072f5..816e0c1 100644
--- a/src/gallium/drivers/softpipe/sp_state_fs.c
+++ b/src/gallium/drivers/softpipe/sp_state_fs.c
@@ -36,6 +36,7 @@
 #include "draw/draw_context.h"
 #include "draw/draw_vs.h"
 #include "tgsi/tgsi_dump.h"
+#include "tgsi/tgsi_exec.h"
 #include "tgsi/tgsi_scan.h"
 #include "tgsi/tgsi_parse.h"
 
@@ -95,10 +96,18 @@ softpipe_bind_fs_state(struct pipe_context *pipe, void *fs)
 void
 softpipe_delete_fs_state(struct pipe_context *pipe, void *fs)
 {
+   struct softpipe_context *softpipe = softpipe_context(pipe);
    struct sp_fragment_shader *state = fs;
 
    assert(fs != softpipe_context(pipe)->fs);
-   
+
+   if (softpipe->fs_machine->Tokens == state->shader.tokens) {
+      /* unbind the shader from the tgsi executor if we're
+       * deleting it.
+       */
+      tgsi_exec_machine_bind_shader(softpipe->fs_machine, NULL, 0, NULL);
+   }
+
    state->delete( state );
 }