[Mesa-dev] [PATCH 3/3] mesa: add more draw time validation for separate shader programs

[Tapani Pälli]

Validation checks that we do not have active shader stages that are
not used by the pipeline.

This fixes a subtest in following CTS test:
	ES31-CTS.sepshaderobjs.StateInteraction

Signed-off-by: Tapani Pälli <tapani.palli at intel.com>
---
 src/mesa/main/api_validate.c | 38 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/src/mesa/main/api_validate.c b/src/mesa/main/api_validate.c
index d693ec6..6a0cbb0 100644
--- a/src/mesa/main/api_validate.c
+++ b/src/mesa/main/api_validate.c
@@ -47,6 +47,44 @@ check_valid_to_render(struct gl_context *ctx, const char *function)
 
    switch (ctx->API) {
    case API_OPENGLES2:
+      /* If SSO in use, validate that all linked program stages are used by
+       * the current pipeline.
+       *
+       * OpenGL ES 3.1 spec (11.1.3.11 Validation):
+       *
+       *    "An INVALID_OPERATION error is generated by any command that trans-
+       *    fers vertices to the GL or launches compute work if the current set
+       *    of active program objects cannot be executed, for reasons including:
+       *
+       *    ...
+       *
+       *    "A program object is active for at least one, but not all of
+       *    the shader stages that were present when the program was linked."
+       *
+       */
+      if (ctx->Pipeline.Current) {
+          struct gl_pipeline_object *pipe = ctx->Pipeline.Current;
+          unsigned i;
+          for (i = 0; i < MESA_SHADER_STAGES; i++) {
+             if (!pipe->CurrentProgram[i])
+                continue;
+
+             /* Check that each active stage of linked program is used.
+              * This is done by comparing ActiveStages masks of program and
+              * pipeline. Program mask must not contain active stages that
+              * are not marked used by the pipeline.
+              */
+             struct gl_shader_program *shProg = pipe->CurrentProgram[i];
+             if (((pipe->ActiveStages & shProg->ActiveStages) ^
+                 shProg->ActiveStages) != 0) {
+                _mesa_error(ctx, GL_INVALID_OPERATION,
+                            "Shader program active for shader stages that "
+                            "are not used by the pipeline");
+                return false;
+             }
+          }
+      }
+
       /* For ES2, we can draw if we have a vertex program/shader). */
       return ctx->VertexProgram._Current != NULL;
 
-- 
2.5.0