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-rw-r--r--ir_copy_propagation.cpp313
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diff --git a/ir_copy_propagation.cpp b/ir_copy_propagation.cpp
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+/*
+ * 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 ir_dead_code.cpp
+ *
+ * Eliminates dead assignments and variable declarations from the code.
+ */
+
+#include <stdio.h>
+#include "ir.h"
+#include "ir_visitor.h"
+#include "ir_basic_block.h"
+#include "ir_copy_propagation.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 ir_copy_propagation_visitor : public ir_visitor {
+public:
+ ir_copy_propagation_visitor(exec_list *acp)
+ {
+ progress = false;
+ this->acp = acp;
+ }
+
+ /**
+ * \name Visit methods
+ *
+ * As typical for the visitor pattern, there must be one \c visit method for
+ * each concrete subclass of \c ir_instruction. Virtual base classes within
+ * the hierarchy should not have \c visit methods.
+ */
+ /*@{*/
+ virtual void visit(ir_variable *);
+ virtual void visit(ir_loop *);
+ virtual void visit(ir_loop_jump *);
+ virtual void visit(ir_function_signature *);
+ virtual void visit(ir_function *);
+ virtual void visit(ir_expression *);
+ virtual void visit(ir_swizzle *);
+ virtual void visit(ir_dereference *);
+ virtual void visit(ir_assignment *);
+ virtual void visit(ir_constant *);
+ virtual void visit(ir_call *);
+ virtual void visit(ir_return *);
+ virtual void visit(ir_if *);
+ /*@}*/
+
+ /** List of acp_entry */
+ exec_list *acp;
+ bool progress;
+};
+
+
+void
+ir_copy_propagation_visitor::visit(ir_variable *ir)
+{
+ (void)ir;
+}
+
+
+void
+ir_copy_propagation_visitor::visit(ir_loop *ir)
+{
+ (void)ir;
+}
+
+void
+ir_copy_propagation_visitor::visit(ir_loop_jump *ir)
+{
+ (void) ir;
+}
+
+
+void
+ir_copy_propagation_visitor::visit(ir_function_signature *ir)
+{
+ (void)ir;
+}
+
+void
+ir_copy_propagation_visitor::visit(ir_function *ir)
+{
+ (void) ir;
+}
+
+void
+ir_copy_propagation_visitor::visit(ir_expression *ir)
+{
+ unsigned int operand;
+
+ for (operand = 0; operand < ir->get_num_operands(); operand++) {
+ ir->operands[operand]->accept(this);
+ }
+}
+
+
+void
+ir_copy_propagation_visitor::visit(ir_swizzle *ir)
+{
+ ir->val->accept(this);
+}
+
+/**
+ * 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!
+ */
+void
+ir_copy_propagation_visitor::visit(ir_dereference *ir)
+{
+ ir_variable *var;
+
+ if (ir->mode == ir_dereference::ir_reference_array) {
+ ir->selector.array_index->accept(this);
+ }
+
+ var = ir->var->as_variable();
+ if (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;
+ }
+ }
+ } else {
+ ir->var->accept(this);
+ }
+}
+
+void
+ir_copy_propagation_visitor::visit(ir_assignment *ir)
+{
+ if (ir->condition)
+ ir->condition->accept(this);
+
+ /* Ignores the LHS. Don't want to rewrite the LHS to point at some
+ * other storage!
+ */
+
+ ir->rhs->accept(this);
+}
+
+
+void
+ir_copy_propagation_visitor::visit(ir_constant *ir)
+{
+ (void) ir;
+}
+
+
+void
+ir_copy_propagation_visitor::visit(ir_call *ir)
+{
+ (void)ir;
+
+ /* Note, if we were to do copy propagation to parameters of calls, we'd
+ * have to be careful about out params.
+ */
+}
+
+
+void
+ir_copy_propagation_visitor::visit(ir_return *ir)
+{
+ ir_rvalue *val = ir->get_value();
+
+ if (val)
+ val->accept(this);
+}
+
+
+void
+ir_copy_propagation_visitor::visit(ir_if *ir)
+{
+ ir->condition->accept(this);
+}
+
+static void
+propagate_copies(ir_instruction *ir, exec_list *acp)
+{
+ ir_copy_propagation_visitor v(acp);
+
+ ir->accept(&v);
+}
+
+static void
+kill_invalidated_copies(ir_assignment *ir, exec_list *acp)
+{
+ ir_dereference *lhs_deref = ir->lhs->as_dereference();
+
+ /* Only handle simple dereferences for now. */
+ if (lhs_deref &&
+ lhs_deref->mode == ir_dereference::ir_reference_variable) {
+ ir_variable *var = lhs_deref->var->as_variable();
+
+ foreach_iter(exec_list_iterator, iter, *acp) {
+ acp_entry *entry = (acp_entry *)iter.get();
+
+ if (entry->lhs == var || entry->rhs == var) {
+ entry->remove();
+ }
+ }
+ } else {
+ /* FINISHME: Only clear out the entries we overwrote here. */
+ acp->make_empty();
+ }
+}
+
+/**
+ * Adds an entry to the available copy list if it's a plain assignment
+ * of a variable to a variable.
+ */
+static void
+add_copy(ir_assignment *ir, exec_list *acp)
+{
+ acp_entry *entry;
+
+ if (ir->condition) {
+ ir_constant *condition = ir->condition->as_constant();
+ if (!condition || !condition->value.b[0])
+ return;
+ }
+
+ ir_dereference *lhs_deref = ir->lhs->as_dereference();
+ if (!lhs_deref || lhs_deref->mode != ir_dereference::ir_reference_variable)
+ return;
+ ir_variable *lhs_var = lhs_deref->var->as_variable();
+
+ ir_dereference *rhs_deref = ir->rhs->as_dereference();
+ if (!rhs_deref || rhs_deref->mode != ir_dereference::ir_reference_variable)
+ return;
+ ir_variable *rhs_var = rhs_deref->var->as_variable();
+
+ entry = new acp_entry(lhs_var, rhs_var);
+ acp->push_tail(entry);
+}
+
+static void
+copy_propagation_basic_block(ir_instruction *first,
+ ir_instruction *last)
+{
+ ir_instruction *ir;
+ /* List of avaialble_copy */
+ exec_list acp;
+
+ for (ir = first;; ir = (ir_instruction *)ir->next) {
+ ir_assignment *ir_assign = ir->as_assignment();
+
+ propagate_copies(ir, &acp);
+
+ if (ir_assign) {
+ kill_invalidated_copies(ir_assign, &acp);
+
+ add_copy(ir_assign, &acp);
+ }
+ if (ir == last)
+ break;
+ }
+}
+
+/**
+ * Does a copy propagation pass on the code present in the instruction stream.
+ */
+bool
+do_copy_propagation(exec_list *instructions)
+{
+ bool progress = false;
+
+ call_for_basic_blocks(instructions, copy_propagation_basic_block);
+
+ /* FINISHME: Return a legit progress value. */
+ return progress;
+}
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