mesa: Disallow relinking if a program is used by an active XFB object.

Paused transform feedback objects may refer to a program other than the
current program.  If any active objects refer to a program, LinkProgram
must reject the request to relink.

The code to detect this is ugly since _mesa_HashWalk is awkward to use,
but unfortunately we can't use hash_table_foreach since there's no way
to get at the underlying struct hash_table (and even then, we'd need to
handle locking somehow).

Fixes the last subcase of Piglit's new ARB_transform_feedback2
api-errors test.

Signed-off-by: Kenneth Graunke <[email protected]>
Reviewed-by: Marek Olšák <[email protected]>

1 files changed, 8 insertions, 7 deletions

diff --git a/src/mesa/main/shaderapi.c b/src/mesa/main/shaderapi.c
index a2386fb133e..4c0484aaf0c 100644
--- a/src/mesa/main/shaderapi.c
+++ b/src/mesa/main/shaderapi.c
@@ -42,6 +42,7 @@
 #include "main/dispatch.h"
 #include "main/enums.h"
 #include "main/hash.h"
+#include "main/hash_table.h"
 #include "main/mtypes.h"
 #include "main/shaderapi.h"
 #include "main/shaderobj.h"
@@ -812,19 +813,19 @@ static void
 link_program(struct gl_context *ctx, GLuint program)
 {
    struct gl_shader_program *shProg;
-   struct gl_transform_feedback_object *obj =
-      ctx->TransformFeedback.CurrentObject;
 
    shProg = _mesa_lookup_shader_program_err(ctx, program, "glLinkProgram");
    if (!shProg)
       return;
 
-   if (obj->Active
-       && (shProg == ctx->Shader.CurrentVertexProgram
-	   || shProg == ctx->Shader.CurrentGeometryProgram
-	   || shProg == ctx->Shader.CurrentFragmentProgram)) {
+   /* From the ARB_transform_feedback2 specification:
+    * "The error INVALID_OPERATION is generated by LinkProgram if <program> is
+    *  the name of a program being used by one or more transform feedback
+    *  objects, even if the objects are not currently bound or are paused."
+    */
+   if (_mesa_transform_feedback_is_using_program(ctx, shProg)) {
       _mesa_error(ctx, GL_INVALID_OPERATION,
-                  "glLinkProgram(transform feedback active)");
+                  "glLinkProgram(transform feedback is using the program)");
       return;
    }