mesa: allocate gl_debug_state on demand

We don't need to allocate all the state related to GL_ARB_debug_output
until some aspect of that extension is actually needed.

The sizeof(gl_debug_state) is huge (~285KB on 64-bit systems), not even
counting the 54(!) hash tables and lists that it contains.  This change
reduces the size of gl_context alone from 431KB bytes to 145KB bytes on
64-bit systems and from 277KB bytes to 78KB bytes on 32-bit systems.

Reviewed-by: Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>

1 files changed, 12 insertions, 4 deletions

diff --git a/src/mesa/main/getstring.c b/src/mesa/main/getstring.c
index 6741267..f8097ef 100644
--- a/src/mesa/main/getstring.c
+++ b/src/mesa/main/getstring.c
@@ -253,14 +253,22 @@ _mesa_GetPointerv( GLenum pname, GLvoid **params )
          *params = (GLvoid *) ctx->Array.VAO->VertexAttrib[VERT_ATTRIB_POINT_SIZE].Ptr;
          break;
       case GL_DEBUG_CALLBACK_FUNCTION_ARB:
-         if (!_mesa_is_desktop_gl(ctx))
+         if (!_mesa_is_desktop_gl(ctx)) {
             goto invalid_pname;
-         *params = (GLvoid *) ctx->Debug.Callback;
+         }
+         else {
+            struct gl_debug_state *debug = _mesa_get_debug_state(ctx);
+            *params = debug ? (void *) debug->Callback : NULL;
+         }
          break;
       case GL_DEBUG_CALLBACK_USER_PARAM_ARB:
-         if (!_mesa_is_desktop_gl(ctx))
+         if (!_mesa_is_desktop_gl(ctx)) {
             goto invalid_pname;
-         *params = (GLvoid *) ctx->Debug.CallbackData;
+         }
+         else {
+            struct gl_debug_state *debug = _mesa_get_debug_state(ctx);
+            *params = debug ? (void *) debug->CallbackData : NULL;
+         }
          break;
       default:
          goto invalid_pname;