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 <[email protected]>
Cc: [email protected]
Reviewed-by: Timothy Arceri <[email protected]>
Reviewed-by: Kenneth Graunke <[email protected]>

1 files changed, 99 insertions, 0 deletions

diff --git a/src/compiler/glsl/ir_array_refcount.cpp b/src/compiler/glsl/ir_array_refcount.cpp
new file mode 100644
index 00000000000..b997d415d1d
--- /dev/null
+++ b/src/compiler/glsl/ir_array_refcount.cpp
@@ -0,0 +1,99 @@
+/*
+ * 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.cpp
+ *
+ * Provides a visitor which produces a list of variables referenced.
+ */
+
+#include "ir.h"
+#include "ir_visitor.h"
+#include "ir_array_refcount.h"
+#include "compiler/glsl_types.h"
+#include "util/hash_table.h"
+
+ir_array_refcount_visitor::ir_array_refcount_visitor()
+{
+   this->mem_ctx = ralloc_context(NULL);
+   this->ht = _mesa_hash_table_create(NULL, _mesa_hash_pointer,
+                                      _mesa_key_pointer_equal);
+}
+
+static void
+free_entry(struct hash_entry *entry)
+{
+   ir_array_refcount_entry *ivre = (ir_array_refcount_entry *) entry->data;
+   delete ivre;
+}
+
+ir_array_refcount_visitor::~ir_array_refcount_visitor()
+{
+   ralloc_free(this->mem_ctx);
+   _mesa_hash_table_destroy(this->ht, free_entry);
+}
+
+ir_array_refcount_entry::ir_array_refcount_entry(ir_variable *var)
+   : var(var), is_referenced(false)
+{
+   /* empty */
+}
+
+
+ir_array_refcount_entry *
+ir_array_refcount_visitor::get_variable_entry(ir_variable *var)
+{
+   assert(var);
+
+   struct hash_entry *e = _mesa_hash_table_search(this->ht, var);
+   if (e)
+      return (ir_array_refcount_entry *)e->data;
+
+   ir_array_refcount_entry *entry = new ir_array_refcount_entry(var);
+   _mesa_hash_table_insert(this->ht, var, entry);
+
+   return entry;
+}
+
+
+ir_visitor_status
+ir_array_refcount_visitor::visit(ir_dereference_variable *ir)
+{
+   ir_variable *const var = ir->variable_referenced();
+   ir_array_refcount_entry *entry = this->get_variable_entry(var);
+
+   entry->is_referenced = true;
+
+   return visit_continue;
+}
+
+
+ir_visitor_status
+ir_array_refcount_visitor::visit_enter(ir_function_signature *ir)
+{
+   /* We don't want to descend into the function parameters and
+    * dead-code eliminate them, so just accept the body here.
+    */
+   visit_list_elements(this, &ir->body);
+   return visit_continue_with_parent;
+}