glsl: Change built-in constant expression evaluation to run the IR.

This removes code duplication with
ir_expression::constant_expression_value and builtins/ir/*.

Signed-off-by: Olivier Galibert <[email protected]>
Reviewed-by: Kenneth Graunke <[email protected]>

1 files changed, 15 insertions, 0 deletions

diff --git a/src/glsl/ir.h b/src/glsl/ir.h
index 92be063747f..9c7961ab92c 100644
--- a/src/glsl/ir.h
+++ b/src/glsl/ir.h
@@ -576,6 +576,21 @@ private:
    const ir_function_signature *origin;
 
    friend class ir_function;
+
+   /**
+    * Helper function to run a list of instructions for constant
+    * expression evaluation.
+    *
+    * The hash table represents the values of the visible variables.
+    * There are no scoping issues because the table is indexed on
+    * ir_variable pointers, not variable names.
+    *
+    * Returns false if the expression is not constant, true otherwise,
+    * and the value in *result if result is non-NULL.
+    */
+   bool constant_expression_evaluate_expression_list(const struct exec_list &body,
+						     struct hash_table *variable_context,
+						     ir_constant **result);
 };