glsl: move to compiler/

Signed-off-by: Emil Velikov <[email protected]>
Acked-by: Matt Turner <[email protected]>
Acked-by: Jose Fonseca <[email protected]>

1 files changed, 218 insertions, 0 deletions

diff --git a/src/compiler/glsl/opt_constant_variable.cpp b/src/compiler/glsl/opt_constant_variable.cpp
new file mode 100644
index 00000000000..3ddb12904c7
--- /dev/null
+++ b/src/compiler/glsl/opt_constant_variable.cpp
@@ -0,0 +1,218 @@
+/*
+ * 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 opt_constant_variable.cpp
+ *
+ * Marks variables assigned a single constant value over the course
+ * of the program as constant.
+ *
+ * The goal here is to trigger further constant folding and then dead
+ * code elimination.  This is common with vector/matrix constructors
+ * and calls to builtin functions.
+ */
+
+#include "ir.h"
+#include "ir_visitor.h"
+#include "ir_optimization.h"
+#include "compiler/glsl_types.h"
+#include "util/hash_table.h"
+
+namespace {
+
+struct assignment_entry {
+   int assignment_count;
+   ir_variable *var;
+   ir_constant *constval;
+   bool our_scope;
+};
+
+class ir_constant_variable_visitor : public ir_hierarchical_visitor {
+public:
+   virtual ir_visitor_status visit_enter(ir_dereference_variable *);
+   virtual ir_visitor_status visit(ir_variable *);
+   virtual ir_visitor_status visit_enter(ir_assignment *);
+   virtual ir_visitor_status visit_enter(ir_call *);
+
+   struct hash_table *ht;
+};
+
+} /* unnamed namespace */
+
+static struct assignment_entry *
+get_assignment_entry(ir_variable *var, struct hash_table *ht)
+{
+   struct hash_entry *hte = _mesa_hash_table_search(ht, var);
+   struct assignment_entry *entry;
+
+   if (hte) {
+      entry = (struct assignment_entry *) hte->data;
+   } else {
+      entry = (struct assignment_entry *) calloc(1, sizeof(*entry));
+      entry->var = var;
+      _mesa_hash_table_insert(ht, var, entry);
+   }
+
+   return entry;
+}
+
+ir_visitor_status
+ir_constant_variable_visitor::visit(ir_variable *ir)
+{
+   struct assignment_entry *entry = get_assignment_entry(ir, this->ht);
+   entry->our_scope = true;
+   return visit_continue;
+}
+
+/* Skip derefs of variables so that we can detect declarations. */
+ir_visitor_status
+ir_constant_variable_visitor::visit_enter(ir_dereference_variable *ir)
+{
+   (void)ir;
+   return visit_continue_with_parent;
+}
+
+ir_visitor_status
+ir_constant_variable_visitor::visit_enter(ir_assignment *ir)
+{
+   ir_constant *constval;
+   struct assignment_entry *entry;
+
+   entry = get_assignment_entry(ir->lhs->variable_referenced(), this->ht);
+   assert(entry);
+   entry->assignment_count++;
+
+   /* If it's already constant, don't do the work. */
+   if (entry->var->constant_value)
+      return visit_continue;
+
+   /* OK, now find if we actually have all the right conditions for
+    * this to be a constant value assigned to the var.
+    */
+   if (ir->condition)
+      return visit_continue;
+
+   ir_variable *var = ir->whole_variable_written();
+   if (!var)
+      return visit_continue;
+
+   /* Ignore buffer variables, since the underlying storage is shared
+    * and we can't be sure that this variable won't be written by another
+    * thread.
+    */
+   if (var->data.mode == ir_var_shader_storage ||
+       var->data.mode == ir_var_shader_shared)
+      return visit_continue;
+
+   constval = ir->rhs->constant_expression_value();
+   if (!constval)
+      return visit_continue;
+
+   /* Mark this entry as having a constant assignment (if the
+    * assignment count doesn't go >1).  do_constant_variable will fix
+    * up the variable with the constant value later.
+    */
+   entry->constval = constval;
+
+   return visit_continue;
+}
+
+ir_visitor_status
+ir_constant_variable_visitor::visit_enter(ir_call *ir)
+{
+   /* Mark any out parameters as assigned to */
+   foreach_two_lists(formal_node, &ir->callee->parameters,
+                     actual_node, &ir->actual_parameters) {
+      ir_rvalue *param_rval = (ir_rvalue *) actual_node;
+      ir_variable *param = (ir_variable *) formal_node;
+
+      if (param->data.mode == ir_var_function_out ||
+	  param->data.mode == ir_var_function_inout) {
+	 ir_variable *var = param_rval->variable_referenced();
+	 struct assignment_entry *entry;
+
+	 assert(var);
+	 entry = get_assignment_entry(var, this->ht);
+	 entry->assignment_count++;
+      }
+   }
+
+   /* Mark the return storage as having been assigned to */
+   if (ir->return_deref != NULL) {
+      ir_variable *var = ir->return_deref->variable_referenced();
+      struct assignment_entry *entry;
+
+      assert(var);
+      entry = get_assignment_entry(var, this->ht);
+      entry->assignment_count++;
+   }
+
+   return visit_continue;
+}
+
+/**
+ * Does a copy propagation pass on the code present in the instruction stream.
+ */
+bool
+do_constant_variable(exec_list *instructions)
+{
+   bool progress = false;
+   ir_constant_variable_visitor v;
+
+   v.ht = _mesa_hash_table_create(NULL, _mesa_hash_pointer,
+                                  _mesa_key_pointer_equal);
+   v.run(instructions);
+
+   struct hash_entry *hte;
+   hash_table_foreach(v.ht, hte) {
+      struct assignment_entry *entry = (struct assignment_entry *) hte->data;
+
+      if (entry->assignment_count == 1 && entry->constval && entry->our_scope) {
+	 entry->var->constant_value = entry->constval;
+	 progress = true;
+      }
+      hte->data = NULL;
+      free(entry);
+   }
+   _mesa_hash_table_destroy(v.ht, NULL);
+
+   return progress;
+}
+
+bool
+do_constant_variable_unlinked(exec_list *instructions)
+{
+   bool progress = false;
+
+   foreach_in_list(ir_instruction, ir, instructions) {
+      ir_function *f = ir->as_function();
+      if (f) {
+	 foreach_in_list(ir_function_signature, sig, &f->signatures) {
+	    if (do_constant_variable(&sig->body))
+	       progress = true;
+	 }
+      }
+   }
+
+   return progress;
+}