glsl: Use simpler visitor to determine which UBO and SSBO blocks are used

Very soon this visitor will get more complicated.  The users of the
existing ir_variable_refcount visitor won't need the coming
functionality, and this use doesn't need much of the functionality of
ir_variable_refcount.

v2: ir_array_refcount_visitor::get_variable_entry cannot return NULL, so
don't check it.  Suggested by Timothy.

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Cc: mesa-stable@lists.freedesktop.org
Reviewed-by: Timothy Arceri <timothy.arceri@collabora.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>

src/compiler/glsl/ir_array_refcount.h

@@ -0,0 +1,65 @@
+/*
+ * Copyright © 2016 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+/**
+ * \file ir_array_refcount.h
+ *
+ * Provides a visitor which produces a list of variables referenced.
+ */
+
+#include "ir.h"
+#include "ir_visitor.h"
+#include "compiler/glsl_types.h"
+
+class ir_array_refcount_entry
+{
+public:
+   ir_array_refcount_entry(ir_variable *var);
+
+   ir_variable *var; /* The key: the variable's pointer. */
+
+   /** Has the variable been referenced? */
+   bool is_referenced;
+};
+
+class ir_array_refcount_visitor : public ir_hierarchical_visitor {
+public:
+   ir_array_refcount_visitor(void);
+   ~ir_array_refcount_visitor(void);
+
+   virtual ir_visitor_status visit(ir_dereference_variable *);
+
+   virtual ir_visitor_status visit_enter(ir_function_signature *);
+
+   /**
+    * Find variable in the hash table, and insert it if not present
+    */
+   ir_array_refcount_entry *get_variable_entry(ir_variable *var);
+
+   /**
+    * Hash table mapping ir_variable to ir_array_refcount_entry.
+    */
+   struct hash_table *ht;
+
+   void *mem_ctx;
+};