From 1028458354773d748278d7719f695eb4c2ffc090 Mon Sep 17 00:00:00 2001
From: Brian Paul <brian.paul@tungstengraphics.com>
Date: Mon, 4 Aug 2008 11:14:12 -0600
Subject: mesa: glsl: check that rhs of const var initializer is also const

---
 src/mesa/shader/slang/slang_codegen.c | 38 +++++++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/src/mesa/shader/slang/slang_codegen.c b/src/mesa/shader/slang/slang_codegen.c
index 70feed73266..691d10b8f1d 100644
--- a/src/mesa/shader/slang/slang_codegen.c
+++ b/src/mesa/shader/slang/slang_codegen.c
@@ -2621,6 +2621,32 @@ _slang_gen_return(slang_assemble_ctx * A, slang_operation *oper)
 }
 
 
+/**
+ * Determine if the given operation/expression is const-valued.
+ */
+static GLboolean
+_slang_is_constant_expr(const slang_operation *oper)
+{
+   slang_variable *var;
+   GLuint i;
+
+   switch (oper->type) {
+   case SLANG_OPER_IDENTIFIER:
+      var = _slang_locate_variable(oper->locals, oper->a_id, GL_TRUE);
+      if (var && var->type.qualifier == SLANG_QUAL_CONST)
+         return GL_TRUE;
+      return GL_FALSE;
+   default:
+      for (i = 0; i < oper->num_children; i++) {
+         if (!_slang_is_constant_expr(&oper->children[i]))
+            return GL_FALSE;
+      }
+      return GL_TRUE;
+   }
+}
+
+
+
 /**
  * Generate IR tree for a variable declaration.
  */
@@ -2671,6 +2697,18 @@ _slang_gen_declaration(slang_assemble_ctx *A, slang_operation *oper)
          slang_info_log_error(A->log, "undefined variable '%s'", varName);
          return NULL;
       }
+
+      if (v->type.qualifier == SLANG_QUAL_CONST) {
+         /* if the variable is const, the initializer must be a const
+          * expression as well.
+          */
+         if (!_slang_is_constant_expr(v->initializer)) {
+            slang_info_log_error(A->log,
+                                 "initializer for %s not constant", varName);
+            return NULL;
+         }
+      }
+
 #if 0
       /* XXX make copy of this initializer? */
       {
-- 
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