xserver and mesa git update 28-12-2010

1 files changed, 142 insertions, 0 deletions

diff --git a/mesalib/src/glsl/opt_dead_code.cpp b/mesalib/src/glsl/opt_dead_code.cpp
new file mode 100644
index 000000000..492ba73a1
--- /dev/null
+++ b/mesalib/src/glsl/opt_dead_code.cpp
@@ -0,0 +1,142 @@
+/*

+ * 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_dead_code.cpp

+ *

+ * Eliminates dead assignments and variable declarations from the code.

+ */

+

+#include "ir.h"

+#include "ir_visitor.h"

+#include "ir_variable_refcount.h"

+#include "glsl_types.h"

+

+static bool debug = false;

+

+/**

+ * Do a dead code pass over instructions and everything that instructions

+ * references.

+ *

+ * Note that this will remove assignments to globals, so it is not suitable

+ * for usage on an unlinked instruction stream.

+ */

+bool

+do_dead_code(exec_list *instructions)

+{

+   ir_variable_refcount_visitor v;

+   bool progress = false;

+

+   v.run(instructions);

+

+   foreach_iter(exec_list_iterator, iter, v.variable_list) {

+      variable_entry *entry = (variable_entry *)iter.get();

+

+      /* Since each assignment is a reference, the refereneced count must be

+       * greater than or equal to the assignment count.  If they are equal,

+       * then all of the references are assignments, and the variable is

+       * dead.

+       *

+       * Note that if the variable is neither assigned nor referenced, both

+       * counts will be zero and will be caught by the equality test.

+       */

+      assert(entry->referenced_count >= entry->assigned_count);

+

+      if (debug) {

+	 printf("%s@%p: %d refs, %d assigns, %sdeclared in our scope\n",

+		entry->var->name, (void *) entry->var,

+		entry->referenced_count, entry->assigned_count,

+		entry->declaration ? "" : "not ");

+      }

+

+      if ((entry->referenced_count > entry->assigned_count)

+	  || !entry->declaration)

+	 continue;

+

+      if (entry->assign) {

+	 /* Remove a single dead assignment to the variable we found.

+	  * Don't do so if it's a shader output, though.

+	  */

+	 if (entry->var->mode != ir_var_out &&

+	     entry->var->mode != ir_var_inout &&

+	     !ir_has_call(entry->assign)) {

+	    entry->assign->remove();

+	    progress = true;

+

+	    if (debug) {

+	       printf("Removed assignment to %s@%p\n",

+		      entry->var->name, (void *) entry->var);

+	    }

+	 }

+      } else {

+	 /* If there are no assignments or references to the variable left,

+	  * then we can remove its declaration.

+	  */

+

+	 /* uniform initializers are precious, and could get used by another

+	  * stage.

+	  */

+	 if (entry->var->mode == ir_var_uniform &&

+	     entry->var->constant_value)

+	    continue;

+

+	 entry->var->remove();

+	 progress = true;

+

+	 if (debug) {

+	    printf("Removed declaration of %s@%p\n",

+		   entry->var->name, (void *) entry->var);

+	 }

+      }

+   }

+

+   return progress;

+}

+

+/**

+ * Does a dead code pass on the functions present in the instruction stream.

+ *

+ * This is suitable for use while the program is not linked, as it will

+ * ignore variable declarations (and the assignments to them) for variables

+ * with global scope.

+ */

+bool

+do_dead_code_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_dead_code(&sig->body))

+	       progress = true;

+	 }

+      }

+   }

+

+   return progress;

+}