glsl2: Factor out the variable refcounting part of ir_dead_code.cpp.

src/glsl/ir_variable_refcount.h

@@ -0,0 +1,87 @@
+/*
+ * Copyright © 2010 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_variable_refcount.h
+ *
+ * Provides a visitor which produces a list of variables referenced,
+ * how many times they were referenced and assigned, and whether they
+ * were defined in the scope.
+ */
+
+#include "ir.h"
+#include "ir_visitor.h"
+#include "glsl_types.h"
+
+class variable_entry : public exec_node
+{
+public:
+   variable_entry(ir_variable *var)
+   {
+      this->var = var;
+      assign = NULL;
+      referenced_count = 0;
+      assigned_count = 0;
+      declaration = false;
+   }
+
+   ir_variable *var; /* The key: the variable's pointer. */
+   ir_assignment *assign; /* An assignment to the variable, if any */
+
+   /** Number of times the variable is referenced, including assignments. */
+   unsigned referenced_count;
+
+   /** Number of times the variable is assigned. */
+   unsigned assigned_count;
+
+   bool declaration; /* If the variable had a decl in the instruction stream */
+};
+
+class ir_variable_refcount_visitor : public ir_hierarchical_visitor {
+public:
+   ir_variable_refcount_visitor(void)
+   {
+      this->mem_ctx = talloc_new(NULL);
+      this->variable_list.make_empty();
+   }
+
+   ~ir_variable_refcount_visitor(void)
+   {
+      this->mem_ctx = talloc_new(NULL);
+   }
+
+   virtual ir_visitor_status visit(ir_variable *);
+   virtual ir_visitor_status visit(ir_dereference_variable *);
+
+   virtual ir_visitor_status visit_enter(ir_function_signature *);
+   virtual ir_visitor_status visit_leave(ir_assignment *);
+
+   variable_entry *get_variable_entry(ir_variable *var);
+
+   bool (*predicate)(ir_instruction *ir);
+
+   /* List of variable_entry */
+   exec_list variable_list;
+
+   void *mem_ctx;
+};