st/mesa: Don't record garbage streamout information in the non-SSO case.

In the non-SSO case, where multiple shader stages are linked together,
we were recording garbage pipe_stream_output_info structures for all
but the last enabled geometry-processing stage.

Specifically, we were using the gl_transform_feedback_info from
shader_program->last_vert_prog (the stage whose outputs will be
recorded)...but were pairing it with the output varying mappings
from the current shader stage.  For example, a program with a VS and
GS, the VS's pipe_shader_state would have a pipe_stream_output_info
based on the GS transform feedback info, but the VS output mapping.

This generally worked out okay because only the pipe_stream_output_info
for the last stage really matters - the others can be ignored.  However,
we'd like to avoid confusing the pipe driver.  In particular, my new
driver translates the stream out information to hardware packets at
bind_{vs,tes,gs}_state() time...and was hitting asserts about garbage
varyings that didn't exist.

This patch changes st/mesa to record a blank pipe_stream_output_info
with num_outputs = 0 for all stages prior to last_vert_prog.  The last
one is captured as normal.

(In the fully-SSO case, nothing should change - each program contains
a single shader stage, so last_vert_prog *is* the current shader.)

Tested with llvmpipe (piglit's gpu profile), and freedreno (a3xx,
gpu profile with -t transform.feedback).  Fixes several hundred CTS
tests on my new driver.

Reviewed-by: Timothy Arceri <[email protected]>

1 files changed, 8 insertions, 11 deletions

diff --git a/src/mesa/state_tracker/st_program.c b/src/mesa/state_tracker/st_program.c
index af86c47b945..3bc7b0649c4 100644
--- a/src/mesa/state_tracker/st_program.c
+++ b/src/mesa/state_tracker/st_program.c
@@ -458,12 +458,9 @@ st_translate_vertex_program(struct st_context *st,
    }
 
    if (stvp->shader_program) {
-      struct gl_program *prog = stvp->shader_program->last_vert_prog;
-      if (prog) {
-         st_translate_stream_output_info2(prog->sh.LinkedTransformFeedback,
-                                          stvp->result_to_output,
-                                          &stvp->tgsi.stream_output);
-      }
+      st_translate_stream_output_info(stvp->Base.sh.LinkedTransformFeedback,
+                                      stvp->result_to_output,
+                                      &stvp->tgsi.stream_output);
 
       st_store_ir_in_disk_cache(st, &stvp->Base, true);
       return true;
@@ -505,7 +502,7 @@ st_translate_vertex_program(struct st_context *st,
                                    output_semantic_name,
                                    output_semantic_index);
 
-      st_translate_stream_output_info(stvp->glsl_to_tgsi,
+      st_translate_stream_output_info(stvp->Base.sh.LinkedTransformFeedback,
                                       stvp->result_to_output,
                                       &stvp->tgsi.stream_output);
 
@@ -1417,7 +1414,7 @@ st_translate_program_common(struct st_context *st,
    }
    ureg_destroy(ureg);
 
-   st_translate_stream_output_info(glsl_to_tgsi,
+   st_translate_stream_output_info(prog->sh.LinkedTransformFeedback,
                                    outputMapping,
                                    &out_state->stream_output);
 
@@ -1464,9 +1461,9 @@ st_translate_program_stream_output(struct gl_program *prog,
       }
    }
 
-   st_translate_stream_output_info2(prog->sh.LinkedTransformFeedback,
-                                    outputMapping,
-                                    stream_output);
+   st_translate_stream_output_info(prog->sh.LinkedTransformFeedback,
+                                   outputMapping,
+                                   stream_output);
 }
 
 /**