glsl: Reject shaders that contain static recursion

The GLSL 1.20 and later specs say:

    "Recursion is not allowed, not even statically. Static recursion is
    present if the static function call graph of the program contains
    cycles."

Recursion is detected and rejected both a compile-time and at
link-time.  The complie-time check happens to detect some cases that
may be removed by various optimization passes.  The spec doesn't seem
to allow this, but other vendors (e.g., NVIDIA) appear to only check
at link-time after all optimizations.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=33885
Reviewed-by: Paul Berry <[email protected]>
Reviewed-by: Eric Anholt <[email protected]>
Reviewed-by: Kenneth Graunke <[email protected]>

1 files changed, 26 insertions, 0 deletions

diff --git a/src/glsl/ir.h b/src/glsl/ir.h
index 9f277380c7d..50a9d6e1991 100644
--- a/src/glsl/ir.h
+++ b/src/glsl/ir.h
@@ -1635,6 +1635,32 @@ visit_exec_list(exec_list *list, ir_visitor *visitor);
  */
 void validate_ir_tree(exec_list *instructions);
 
+struct _mesa_glsl_parse_state;
+struct gl_shader_program;
+
+/**
+ * Detect whether an unlinked shader contains static recursion
+ *
+ * If the list of instructions is determined to contain static recursion,
+ * \c _mesa_glsl_error will be called to emit error messages for each function
+ * that is in the recursion cycle.
+ */
+void
+detect_recursion_unlinked(struct _mesa_glsl_parse_state *state,
+			  exec_list *instructions);
+
+/**
+ * Detect whether a linked shader contains static recursion
+ *
+ * If the list of instructions is determined to contain static recursion,
+ * \c link_error_printf will be called to emit error messages for each function
+ * that is in the recursion cycle.  In addition,
+ * \c gl_shader_program::LinkStatus will be set to false.
+ */
+void
+detect_recursion_linked(struct gl_shader_program *prog,
+			exec_list *instructions);
+
 /**
  * Make a clone of each IR instruction in a list
  *