xserver and mesa git update 28-12-2010

1 files changed, 348 insertions, 0 deletions

diff --git a/mesalib/src/glsl/opt_copy_propagation.cpp b/mesalib/src/glsl/opt_copy_propagation.cpp
new file mode 100644
index 000000000..088c4bdbc
--- /dev/null
+++ b/mesalib/src/glsl/opt_copy_propagation.cpp
@@ -0,0 +1,348 @@
+/*

+ * 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_copy_propagation.cpp

+ *

+ * Moves usage of recently-copied variables to the previous copy of

+ * the variable.

+ *

+ * This should reduce the number of MOV instructions in the generated

+ * programs unless copy propagation is also done on the LIR, and may

+ * help anyway by triggering other optimizations that live in the HIR.

+ */

+

+#include "ir.h"

+#include "ir_visitor.h"

+#include "ir_basic_block.h"

+#include "ir_optimization.h"

+#include "glsl_types.h"

+

+class acp_entry : public exec_node

+{

+public:

+   acp_entry(ir_variable *lhs, ir_variable *rhs)

+   {

+      assert(lhs);

+      assert(rhs);

+      this->lhs = lhs;

+      this->rhs = rhs;

+   }

+

+   ir_variable *lhs;

+   ir_variable *rhs;

+};

+

+

+class kill_entry : public exec_node

+{

+public:

+   kill_entry(ir_variable *var)

+   {

+      assert(var);

+      this->var = var;

+   }

+

+   ir_variable *var;

+};

+

+class ir_copy_propagation_visitor : public ir_hierarchical_visitor {

+public:

+   ir_copy_propagation_visitor()

+   {

+      progress = false;

+      mem_ctx = talloc_new(0);

+      this->acp = new(mem_ctx) exec_list;

+      this->kills = new(mem_ctx) exec_list;

+   }

+   ~ir_copy_propagation_visitor()

+   {

+      talloc_free(mem_ctx);

+   }

+

+   virtual ir_visitor_status visit(class ir_dereference_variable *);

+   virtual ir_visitor_status visit_enter(class ir_loop *);

+   virtual ir_visitor_status visit_enter(class ir_function_signature *);

+   virtual ir_visitor_status visit_enter(class ir_function *);

+   virtual ir_visitor_status visit_leave(class ir_assignment *);

+   virtual ir_visitor_status visit_enter(class ir_call *);

+   virtual ir_visitor_status visit_enter(class ir_if *);

+

+   void add_copy(ir_assignment *ir);

+   void kill(ir_variable *ir);

+   void handle_if_block(exec_list *instructions);

+

+   /** List of acp_entry: The available copies to propagate */

+   exec_list *acp;

+   /**

+    * List of kill_entry: The variables whose values were killed in this

+    * block.

+    */

+   exec_list *kills;

+

+   bool progress;

+

+   bool killed_all;

+

+   void *mem_ctx;

+};

+

+ir_visitor_status

+ir_copy_propagation_visitor::visit_enter(ir_function_signature *ir)

+{

+   /* Treat entry into a function signature as a completely separate

+    * block.  Any instructions at global scope will be shuffled into

+    * main() at link time, so they're irrelevant to us.

+    */

+   exec_list *orig_acp = this->acp;

+   exec_list *orig_kills = this->kills;

+   bool orig_killed_all = this->killed_all;

+

+   this->acp = new(mem_ctx) exec_list;

+   this->kills = new(mem_ctx) exec_list;

+   this->killed_all = false;

+

+   visit_list_elements(this, &ir->body);

+

+   this->kills = orig_kills;

+   this->acp = orig_acp;

+   this->killed_all = orig_killed_all;

+

+   return visit_continue_with_parent;

+}

+

+ir_visitor_status

+ir_copy_propagation_visitor::visit_leave(ir_assignment *ir)

+{

+   kill(ir->lhs->variable_referenced());

+

+   add_copy(ir);

+

+   return visit_continue;

+}

+

+ir_visitor_status

+ir_copy_propagation_visitor::visit_enter(ir_function *ir)

+{

+   (void) ir;

+   return visit_continue;

+}

+

+/**

+ * Replaces dereferences of ACP RHS variables with ACP LHS variables.

+ *

+ * This is where the actual copy propagation occurs.  Note that the

+ * rewriting of ir_dereference means that the ir_dereference instance

+ * must not be shared by multiple IR operations!

+ */

+ir_visitor_status

+ir_copy_propagation_visitor::visit(ir_dereference_variable *ir)

+{

+   if (this->in_assignee)

+      return visit_continue;

+

+   ir_variable *var = ir->var;

+

+   foreach_iter(exec_list_iterator, iter, *this->acp) {

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

+

+      if (var == entry->lhs) {

+	 ir->var = entry->rhs;

+	 this->progress = true;

+	 break;

+      }

+   }

+

+   return visit_continue;

+}

+

+

+ir_visitor_status

+ir_copy_propagation_visitor::visit_enter(ir_call *ir)

+{

+   /* Do copy propagation on call parameters, but skip any out params */

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

+   foreach_iter(exec_list_iterator, iter, ir->actual_parameters) {

+      ir_variable *sig_param = (ir_variable *)sig_param_iter.get();

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

+      if (sig_param->mode != ir_var_out && sig_param->mode != ir_var_inout) {

+         ir->accept(this);

+      }

+      sig_param_iter.next();

+   }

+

+   /* Since we're unlinked, we don't (necssarily) know the side effects of

+    * this call.  So kill all copies.

+    */

+   acp->make_empty();

+   this->killed_all = true;

+

+   return visit_continue_with_parent;

+}

+

+void

+ir_copy_propagation_visitor::handle_if_block(exec_list *instructions)

+{

+   exec_list *orig_acp = this->acp;

+   exec_list *orig_kills = this->kills;

+   bool orig_killed_all = this->killed_all;

+

+   this->acp = new(mem_ctx) exec_list;

+   this->kills = new(mem_ctx) exec_list;

+   this->killed_all = false;

+

+   /* Populate the initial acp with a copy of the original */

+   foreach_iter(exec_list_iterator, iter, *orig_acp) {

+      acp_entry *a = (acp_entry *)iter.get();

+      this->acp->push_tail(new(this->mem_ctx) acp_entry(a->lhs, a->rhs));

+   }

+

+   visit_list_elements(this, instructions);

+

+   if (this->killed_all) {

+      orig_acp->make_empty();

+   }

+

+   exec_list *new_kills = this->kills;

+   this->kills = orig_kills;

+   this->acp = orig_acp;

+   this->killed_all = this->killed_all || orig_killed_all;

+

+   foreach_iter(exec_list_iterator, iter, *new_kills) {

+      kill_entry *k = (kill_entry *)iter.get();

+      kill(k->var);

+   }

+}

+

+ir_visitor_status

+ir_copy_propagation_visitor::visit_enter(ir_if *ir)

+{

+   ir->condition->accept(this);

+

+   handle_if_block(&ir->then_instructions);

+   handle_if_block(&ir->else_instructions);

+

+   /* handle_if_block() already descended into the children. */

+   return visit_continue_with_parent;

+}

+

+ir_visitor_status

+ir_copy_propagation_visitor::visit_enter(ir_loop *ir)

+{

+   exec_list *orig_acp = this->acp;

+   exec_list *orig_kills = this->kills;

+   bool orig_killed_all = this->killed_all;

+

+   /* FINISHME: For now, the initial acp for loops is totally empty.

+    * We could go through once, then go through again with the acp

+    * cloned minus the killed entries after the first run through.

+    */

+   this->acp = new(mem_ctx) exec_list;

+   this->kills = new(mem_ctx) exec_list;

+   this->killed_all = false;

+

+   visit_list_elements(this, &ir->body_instructions);

+

+   if (this->killed_all) {

+      orig_acp->make_empty();

+   }

+

+   exec_list *new_kills = this->kills;

+   this->kills = orig_kills;

+   this->acp = orig_acp;

+   this->killed_all = this->killed_all || orig_killed_all;

+

+   foreach_iter(exec_list_iterator, iter, *new_kills) {

+      kill_entry *k = (kill_entry *)iter.get();

+      kill(k->var);

+   }

+

+   /* already descended into the children. */

+   return visit_continue_with_parent;

+}

+

+void

+ir_copy_propagation_visitor::kill(ir_variable *var)

+{

+   assert(var != NULL);

+

+   /* Remove any entries currently in the ACP for this kill. */

+   foreach_iter(exec_list_iterator, iter, *acp) {

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

+

+      if (entry->lhs == var || entry->rhs == var) {

+	 entry->remove();

+      }

+   }

+

+   /* Add the LHS variable to the list of killed variables in this block.

+    */

+   this->kills->push_tail(new(this->mem_ctx) kill_entry(var));

+}

+

+/**

+ * Adds an entry to the available copy list if it's a plain assignment

+ * of a variable to a variable.

+ */

+void

+ir_copy_propagation_visitor::add_copy(ir_assignment *ir)

+{

+   acp_entry *entry;

+

+   if (ir->condition) {

+      ir_constant *condition = ir->condition->as_constant();

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

+	 return;

+   }

+

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

+   ir_variable *rhs_var = ir->rhs->whole_variable_referenced();

+

+   if ((lhs_var != NULL) && (rhs_var != NULL)) {

+      if (lhs_var == rhs_var) {

+	 /* This is a dumb assignment, but we've conveniently noticed

+	  * it here.  Removing it now would mess up the loop iteration

+	  * calling us.  Just flag it to not execute, and someone else

+	  * will clean up the mess.

+	  */

+	 ir->condition = new(talloc_parent(ir)) ir_constant(false);

+	 this->progress = true;

+      } else {

+	 entry = new(this->mem_ctx) acp_entry(lhs_var, rhs_var);

+	 this->acp->push_tail(entry);

+      }

+   }

+}

+

+/**

+ * Does a copy propagation pass on the code present in the instruction stream.

+ */

+bool

+do_copy_propagation(exec_list *instructions)

+{

+   ir_copy_propagation_visitor v;

+

+   visit_list_elements(&v, instructions);

+

+   return v.progress;

+}