xserver and mesa git update 28-12-2010

1 files changed, 198 insertions, 0 deletions

diff --git a/mesalib/src/glsl/opt_constant_variable.cpp b/mesalib/src/glsl/opt_constant_variable.cpp
new file mode 100644
index 000000000..fedae851f
--- /dev/null
+++ b/mesalib/src/glsl/opt_constant_variable.cpp
@@ -0,0 +1,198 @@
+/*

+ * 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 "glsl_types.h"

+

+struct assignment_entry {

+   exec_node link;

+   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 *);

+

+   exec_list list;

+};

+

+static struct assignment_entry *

+get_assignment_entry(ir_variable *var, exec_list *list)

+{

+   struct assignment_entry *entry;

+

+   foreach_list_typed(struct assignment_entry, entry, link, list) {

+      if (entry->var == var)

+	 return entry;

+   }

+

+   entry = (struct assignment_entry *)calloc(1, sizeof(*entry));

+   entry->var = var;

+   list->push_head(&entry->link);

+   return entry;

+}

+

+ir_visitor_status

+ir_constant_variable_visitor::visit(ir_variable *ir)

+{

+   struct assignment_entry *entry = get_assignment_entry(ir, &this->list);

+   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->list);

+   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) {

+      constval = ir->condition->constant_expression_value();

+      if (!constval || !constval->value.b[0])

+	 return visit_continue;

+   }

+

+   ir_variable *var = ir->whole_variable_written();

+   if (!var)

+      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)

+{

+   exec_list_iterator sig_iter = ir->get_callee()->parameters.iterator();

+   foreach_iter(exec_list_iterator, iter, *ir) {

+      ir_rvalue *param_rval = (ir_rvalue *)iter.get();

+      ir_variable *param = (ir_variable *)sig_iter.get();

+

+      if (param->mode == ir_var_out ||

+	  param->mode == ir_var_inout) {

+	 ir_variable *var = param_rval->variable_referenced();

+	 struct assignment_entry *entry;

+

+	 assert(var);

+	 entry = get_assignment_entry(var, &this->list);

+	 entry->assignment_count++;

+      }

+      sig_iter.next();

+   }

+   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.run(instructions);

+

+   while (!v.list.is_empty()) {

+

+      struct assignment_entry *entry;

+      entry = exec_node_data(struct assignment_entry, v.list.head, link);

+

+      if (entry->assignment_count == 1 && entry->constval && entry->our_scope) {

+	 entry->var->constant_value = entry->constval;

+	 progress = true;

+      }

+      entry->link.remove();

+      free(entry);

+   }

+

+   return progress;

+}

+

+bool

+do_constant_variable_unlinked(exec_list *instructions)

+{

+   bool progress = false;

+

+   foreach_iter(exec_list_iterator, iter, *instructions) {

+      ir_instruction *ir = (ir_instruction *)iter.get();

+      ir_function *f = ir->as_function();

+      if (f) {

+	 foreach_iter(exec_list_iterator, sigiter, *f) {

+	    ir_function_signature *sig =

+	       (ir_function_signature *) sigiter.get();

+	    if (do_constant_variable(&sig->body))

+	       progress = true;

+	 }

+      }

+   }

+

+   return progress;

+}