i965g: add lots of error checks and early returns

Any allocation that may fail should be checked, and propogate the
error upwards.  At the highest level we will flush batch and retry.

This is an alternate strategy to what the original DRI driver did of
attempting to flush batch from the lowest levels (eg inside
BEGIN_BATCH).  The trouble with that strategy was that flushes could
occur at unexpected times, and additionally there was a need for a
wierd notification mechanism to propogate the 'lost context' state
back up to higher levels.

Propogating the errors directly gives us a lot of flexibility how to
deal with these states, at the expense of a lot more checking in the
code.

Will add some sanity checks later to make sure that out-of-memory
conditions are properly escalated and not lost halfway up the stack.

1 files changed, 41 insertions, 37 deletions

diff --git a/src/gallium/drivers/i965/brw_wm.c b/src/gallium/drivers/i965/brw_wm.c
index 815ae8c51a..93f90bf329 100644
--- a/src/gallium/drivers/i965/brw_wm.c
+++ b/src/gallium/drivers/i965/brw_wm.c
@@ -137,30 +137,26 @@ brw_wm_linear_shader_emit(struct brw_context *brw, struct brw_wm_compile *c)
  * Depending on the instructions used (i.e. flow control instructions)
  * we'll use one of two code generators.
  */
-static int do_wm_prog( struct brw_context *brw,
-			struct brw_fragment_shader *fp, 
-			struct brw_wm_prog_key *key)
+static enum pipe_error do_wm_prog( struct brw_context *brw,
+                                   struct brw_fragment_shader *fp, 
+                                   struct brw_wm_prog_key *key,
+                                   struct brw_winsys_buffer **bo_out)
 {
+   enum pipe_error ret;
    struct brw_wm_compile *c;
    const GLuint *program;
    GLuint program_size;
 
-   c = brw->wm.compile_data;
-   if (c == NULL) {
-      brw->wm.compile_data = calloc(1, sizeof(*brw->wm.compile_data));
-      c = brw->wm.compile_data;
-      if (c == NULL) {
-         /* Ouch - big out of memory problem.  Can't continue
-          * without triggering a segfault, no way to signal,
-          * so just return.
-          */
+   if (brw->wm.compile_data == NULL) {
+      brw->wm.compile_data = MALLOC(sizeof(*brw->wm.compile_data));
+      if (!brw->wm.compile_data) 
          return PIPE_ERROR_OUT_OF_MEMORY;
-      }
-   } else {
-      memset(c, 0, sizeof(*brw->wm.compile_data));
    }
-   memcpy(&c->key, key, sizeof(*key));
 
+   c = brw->wm.compile_data;
+   memset(c, 0, sizeof *c);
+
+   c->key = *key;
    c->fp = fp;
    c->env_param = NULL; /*brw->intel.ctx.FragmentProgram.Parameters;*/
 
@@ -190,17 +186,21 @@ static int do_wm_prog( struct brw_context *brw,
 
    /* get the program
     */
-   program = brw_get_program(&c->func, &program_size);
-
-   brw->sws->bo_unreference(brw->wm.prog_bo);
-   brw->wm.prog_bo = brw_upload_cache( &brw->cache, BRW_WM_PROG,
-				       &c->key, sizeof(c->key),
-				       NULL, 0,
-				       program, program_size,
-				       &c->prog_data,
-				       &brw->wm.prog_data );
-
-   return 0;
+   ret = brw_get_program(&c->func, &program, &program_size);
+   if (ret)
+      return ret;
+
+   ret = brw_upload_cache( &brw->cache, BRW_WM_PROG,
+                           &c->key, sizeof(c->key),
+                           NULL, 0,
+                           program, program_size,
+                           &c->prog_data,
+                           &brw->wm.prog_data,
+                           bo_out );
+   if (ret)
+      return ret;
+
+   return PIPE_OK;
 }
 
 
@@ -267,24 +267,28 @@ static void brw_wm_populate_key( struct brw_context *brw,
 }
 
 
-static int brw_prepare_wm_prog(struct brw_context *brw)
+static enum pipe_error brw_prepare_wm_prog(struct brw_context *brw)
 {
    struct brw_wm_prog_key key;
    struct brw_fragment_shader *fs = brw->curr.fragment_shader;
+   enum pipe_error ret;
      
    brw_wm_populate_key(brw, &key);
 
    /* Make an early check for the key.
     */
-   brw->sws->bo_unreference(brw->wm.prog_bo);
-   brw->wm.prog_bo = brw_search_cache(&brw->cache, BRW_WM_PROG,
-				      &key, sizeof(key),
-				      NULL, 0,
-				      &brw->wm.prog_data);
-   if (brw->wm.prog_bo == NULL)
-      return do_wm_prog(brw, fs, &key);
-
-   return 0;
+   if (brw_search_cache(&brw->cache, BRW_WM_PROG,
+                        &key, sizeof(key),
+                        NULL, 0,
+                        &brw->wm.prog_data,
+                        &brw->wm.prog_bo))
+      return PIPE_OK;
+
+   ret = do_wm_prog(brw, fs, &key, &brw->wm.prog_bo);
+   if (ret)
+      return ret;
+
+   return PIPE_OK;
 }