glsl: In ir_validate, check that ir_loop::counter always refers to a new var.

The compiler back-ends (i965's fs_visitor and brw_visitor,
ir_to_mesa_visitor, and glsl_to_tgsi_visitor) have been assuming this
for some time.  Thanks to the preceding patch, the compiler front-end
no longer breaks this assumption.

This patch adds code to validate the assumption so that if we have
future bugs, we'll be able to catch them earlier.

Reviewed-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>

diff --git a/src/glsl/ir_validate.cpp b/src/glsl/ir_validate.cpp
index 13e41a0..26d6388 100644 (file)
--- a/src/glsl/ir_validate.cpp
+++ b/src/glsl/ir_validate.cpp
@@ -63,6 +63,7 @@ public:
 
    virtual ir_visitor_status visit_enter(ir_if *ir);
 
+   virtual ir_visitor_status visit_enter(ir_loop *ir);
    virtual ir_visitor_status visit_leave(ir_loop *ir);
    virtual ir_visitor_status visit_enter(ir_function *ir);
    virtual ir_visitor_status visit_leave(ir_function *ir);
@@ -149,6 +150,18 @@ ir_validate::visit_enter(ir_if *ir)
 
 
 ir_visitor_status
+ir_validate::visit_enter(ir_loop *ir)
+{
+   if (ir->counter != NULL && hash_table_find(ht, ir->counter) != NULL) {
+      printf("ir_loop @ %p specifies already-declared variable `%s' @ %p\n",
+             (void *) ir, ir->counter->name, (void *) ir->counter);
+      abort();
+   }
+   return visit_continue;
+}
+
+
+ir_visitor_status
 ir_validate::visit_leave(ir_loop *ir)
 {
    if (ir->counter != NULL) {