[Mesa-dev] [PATCH 4/8] mesa: Only validate shaders that can exist in the context

[Ian Romanick]

From: Ian Romanick <ian.d.romanick at intel.com>

On Bay Trail-D using Fedora 20 compile flags (-m64 -O2 -mtune=generic
for 64-bit and -m32 -march=i686 -mtune=atom for 32-bit), affects
Gl32Batch7:

32-bit: Difference at 95.0% confidence 0.495267% +/- 0.202063% (n=40)
64-bit: Difference at 95.0% confidence 3.57576% +/- 0.288175% (n=40)

Signed-off-by: Ian Romanick <ian.d.romanick at intel.com>
---
 src/mesa/main/context.c | 78 +++++++++++++++++++++++++++++++------------------
 1 file changed, 49 insertions(+), 29 deletions(-)

diff --git a/src/mesa/main/context.c b/src/mesa/main/context.c
index 400c158..74f9004 100644
--- a/src/mesa/main/context.c
+++ b/src/mesa/main/context.c
@@ -1903,49 +1903,69 @@ shader_linked_or_absent(struct gl_context *ctx,
 GLboolean
 _mesa_valid_to_render(struct gl_context *ctx, const char *where)
 {
-   bool from_glsl_shader[MESA_SHADER_COMPUTE] = { false };
    unsigned i;
 
    /* This depends on having up to date derived state (shaders) */
    if (ctx->NewState)
       _mesa_update_state(ctx);
 
-   for (i = 0; i < MESA_SHADER_COMPUTE; i++) {
-      if (!shader_linked_or_absent(ctx, ctx->_Shader->CurrentProgram[i],
-                                   &from_glsl_shader[i], where))
-         return GL_FALSE;
-   }
+   if (ctx->API == API_OPENGL_CORE || ctx->API == API_OPENGLES2) {
+      bool from_glsl_shader[MESA_SHADER_COMPUTE] = { false };
 
-   /* Any shader stages that are not supplied by the GLSL shader and have
-    * assembly shaders enabled must now be validated.
-    */
-   if (!from_glsl_shader[MESA_SHADER_VERTEX]
-       && ctx->VertexProgram.Enabled && !ctx->VertexProgram._Enabled) {
-      _mesa_error(ctx, GL_INVALID_OPERATION,
-		  "%s(vertex program not valid)", where);
-      return GL_FALSE;
-   }
+      for (i = 0; i < MESA_SHADER_COMPUTE; i++) {
+         if (!shader_linked_or_absent(ctx, ctx->_Shader->CurrentProgram[i],
+                                      &from_glsl_shader[i], where))
+            return GL_FALSE;
+      }
 
-   /* FINISHME: If GL_NV_geometry_program4 is ever supported, the current
-    * FINISHME: geometry program should validated here.
-    */
-   (void) from_glsl_shader[MESA_SHADER_GEOMETRY];
+      /* In OpenGL Core Profile and OpenGL ES 2.0 / 3.0, there are no assembly
+       * shaders.  Don't check state related to those.
+       */
+   } else {
+      bool has_vertex_shader = false;
+      bool has_fragment_shader = false;
+
+      /* In OpenGL Compatibility Profile, there is only vertex shader and
+       * fragment shader.  We take this path also for API_OPENGLES because
+       * optimizing that path would make the other (more common) paths
+       * slightly slower.
+       */
+      if (!shader_linked_or_absent(ctx,
+                                   ctx->_Shader->CurrentProgram[MESA_SHADER_VERTEX],
+                                   &has_vertex_shader, where))
+         return GL_FALSE;
 
-   if (!from_glsl_shader[MESA_SHADER_FRAGMENT]) {
-      if (ctx->FragmentProgram.Enabled && !ctx->FragmentProgram._Enabled) {
-	 _mesa_error(ctx, GL_INVALID_OPERATION,
-		     "%s(fragment program not valid)", where);
-	 return GL_FALSE;
-      }
+      if (!shader_linked_or_absent(ctx,
+                                   ctx->_Shader->CurrentProgram[MESA_SHADER_FRAGMENT],
+                                   &has_fragment_shader, where))
+         return GL_FALSE;
 
-      /* If drawing to integer-valued color buffers, there must be an
-       * active fragment shader (GL_EXT_texture_integer).
+      /* Any shader stages that are not supplied by the GLSL shader and have
+       * assembly shaders enabled must now be validated.
        */
-      if (ctx->DrawBuffer && ctx->DrawBuffer->_IntegerColor) {
+      if (!has_vertex_shader
+          && ctx->VertexProgram.Enabled && !ctx->VertexProgram._Enabled) {
          _mesa_error(ctx, GL_INVALID_OPERATION,
-                     "%s(integer format but no fragment shader)", where);
+                     "%s(vertex program not valid)", where);
          return GL_FALSE;
       }
+
+      if (!has_fragment_shader) {
+         if (ctx->FragmentProgram.Enabled && !ctx->FragmentProgram._Enabled) {
+            _mesa_error(ctx, GL_INVALID_OPERATION,
+                        "%s(fragment program not valid)", where);
+            return GL_FALSE;
+         }
+
+         /* If drawing to integer-valued color buffers, there must be an
+          * active fragment shader (GL_EXT_texture_integer).
+          */
+         if (ctx->DrawBuffer && ctx->DrawBuffer->_IntegerColor) {
+            _mesa_error(ctx, GL_INVALID_OPERATION,
+                        "%s(integer format but no fragment shader)", where);
+            return GL_FALSE;
+         }
+      }
    }
 
    /* A pipeline object is bound */
-- 
1.8.1.4