mesa: Add a _mesa_active_fragment_shader_has_side_effects helper

Some drivers can disable the FS unit if there is nothing in the shader code
that writes to an output (i.e. color, depth, etc). Right now, mesa has
a function to check for atomic buffers and the i965 driver also checks for
images. Refactor this logic into a generic function that we can use for
any source of side effects in a fragment shader. Suggested by Jason.

v2:
- Use '_Shader', as suggested by Tapani, to fix the following CTS test:

ES31-CTS.shader_atomic_counters.advanced-usage-many-draw-calls2

Reviewed-by: Francisco Jerez <[email protected]>

1 files changed, 12 insertions, 3 deletions

diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h
index 707ebb9872a..c57ec0cd0d0 100644
--- a/src/mesa/main/mtypes.h
+++ b/src/mesa/main/mtypes.h
@@ -4535,11 +4535,20 @@ enum _debug
    DEBUG_INCOMPLETE_FBO         = (1 << 3)
 };
 
+/**
+ * Checks if the active fragment shader program can have side effects due
+ * to use of things like atomic buffers or images
+ */
 static inline bool
-_mesa_active_fragment_shader_has_atomic_ops(const struct gl_context *ctx)
+_mesa_active_fragment_shader_has_side_effects(const struct gl_context *ctx)
 {
-   return ctx->Shader._CurrentFragmentProgram != NULL &&
-      ctx->Shader._CurrentFragmentProgram->_LinkedShaders[MESA_SHADER_FRAGMENT]->NumAtomicBuffers > 0;
+   const struct gl_shader *sh;
+
+   if (!ctx->_Shader->_CurrentFragmentProgram)
+      return false;
+
+   sh = ctx->_Shader->_CurrentFragmentProgram->_LinkedShaders[MESA_SHADER_FRAGMENT];
+   return sh->NumAtomicBuffers > 0 || sh->NumImages > 0;
 }
 
 #ifdef __cplusplus