ir_reader: Emit global variables at the top of the instruction list.

Since functions are emitted when scanning for prototypes, functions
always come first, even if the original IR listed the variable
declarations first.

Fixes an ir_validate error (to be turned on in the next commit).

diff --git a/src/glsl/ir_reader.cpp b/src/glsl/ir_reader.cpp
index 1b0815727253a66a8b1427c95c24efd749b7ffc2..408c20e88c9e65b51f845f862a1f1013194d94e2 100644 (file)
--- a/src/glsl/ir_reader.cpp
+++ b/src/glsl/ir_reader.cpp
@@ -337,8 +337,17 @@ read_instructions(_mesa_glsl_parse_state *st, exec_list *instructions,
    foreach_iter(exec_list_iterator, it, list->subexpressions) {
       s_expression *sub = (s_expression*) it.get();
       ir_instruction *ir = read_instruction(st, sub, loop_ctx);
-      if (ir != NULL)
-        instructions->push_tail(ir);
+      if (ir != NULL) {
+        /* Global variable declarations should be moved to the top, before
+         * any functions that might use them.  Functions are added to the
+         * instruction stream when scanning for prototypes, so without this
+         * hack, they always appear before variable declarations.
+         */
+        if (st->current_function == NULL && ir->as_variable() != NULL)
+           instructions->push_head(ir);
+        else
+           instructions->push_tail(ir);
+      }
    }
 }