src/compiler/glsl/ir_array_refcount.cpp - third_party/mesa - Git at Google

 /*
  * Copyright © 2016 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_array_refcount.cpp
  *
  * Provides a visitor which produces a list of variables referenced.
  */

 #include "ir.h"
 #include "ir_visitor.h"
 #include "ir_array_refcount.h"
 #include "compiler/glsl_types.h"
 #include "util/hash_table.h"

 ir_array_refcount_visitor::ir_array_refcount_visitor()
    : last_array_deref(0), derefs(0), num_derefs(0), derefs_size(0)
 {
    this->mem_ctx = ralloc_context(NULL);
    this->ht = _mesa_pointer_hash_table_create(NULL);
 }

 static void
 free_entry(struct hash_entry *entry)
 {
    ir_array_refcount_entry *ivre = (ir_array_refcount_entry *) entry->data;
    delete ivre;
 }

 ir_array_refcount_visitor::~ir_array_refcount_visitor()
 {
    ralloc_free(this->mem_ctx);
    _mesa_hash_table_destroy(this->ht, free_entry);
 }

 ir_array_refcount_entry::ir_array_refcount_entry(ir_variable *var)
    : var(var), is_referenced(false)
 {
    num_bits = MAX2(1, var->type->arrays_of_arrays_size());
    bits = new BITSET_WORD[BITSET_WORDS(num_bits)];
    memset(bits, 0, BITSET_WORDS(num_bits) * sizeof(bits[0]));

    /* Count the "depth" of the arrays-of-arrays. */
    array_depth = 0;
    for (const glsl_type *type = var->type;
         type->is_array();
         type = type->fields.array) {
       array_depth++;
    }
 }


 ir_array_refcount_entry::~ir_array_refcount_entry()
 {
    delete [] bits;
 }


 void
 ir_array_refcount_entry::mark_array_elements_referenced(const array_deref_range *dr,
                                                         unsigned count)
 {
    if (count != array_depth)
       return;

    mark_array_elements_referenced(dr, count, 1, 0);
 }

 void
 ir_array_refcount_entry::mark_array_elements_referenced(const array_deref_range *dr,
                                                         unsigned count,
                                                         unsigned scale,
                                                         unsigned linearized_index)
 {
    /* Walk through the list of array dereferences in least- to
     * most-significant order.  Along the way, accumulate the current
     * linearized offset and the scale factor for each array-of-.
     */
    for (unsigned i = 0; i < count; i++) {
       if (dr[i].index < dr[i].size) {
          linearized_index += dr[i].index * scale;
          scale *= dr[i].size;
       } else {
          /* For each element in the current array, update the count and
           * offset, then recurse to process the remaining arrays.
           *
           * There is some inefficency here if the last element in the
           * array_deref_range list specifies the entire array.  In that case,
           * the loop will make recursive calls with count == 0.  In the call,
           * all that will happen is the bit will be set.
           */
          for (unsigned j = 0; j < dr[i].size; j++) {
             mark_array_elements_referenced(&dr[i + 1],
                                            count - (i + 1),
                                            scale * dr[i].size,
                                            linearized_index + (j * scale));
          }

          return;
       }
    }

    BITSET_SET(bits, linearized_index);
 }

 ir_array_refcount_entry *
 ir_array_refcount_visitor::get_variable_entry(ir_variable *var)
 {
    assert(var);

    struct hash_entry *e = _mesa_hash_table_search(this->ht, var);
    if (e)
       return (ir_array_refcount_entry *)e->data;

    ir_array_refcount_entry *entry = new ir_array_refcount_entry(var);
    _mesa_hash_table_insert(this->ht, var, entry);

    return entry;
 }


 array_deref_range *
 ir_array_refcount_visitor::get_array_deref()
 {
    if ((num_derefs + 1) * sizeof(array_deref_range) > derefs_size) {
       void *ptr = reralloc_size(mem_ctx, derefs, derefs_size + 4096);

       if (ptr == NULL)
          return NULL;

       derefs_size += 4096;
       derefs = (array_deref_range *)ptr;
    }

    array_deref_range *d = &derefs[num_derefs];
    num_derefs++;

    return d;
 }

 ir_visitor_status
 ir_array_refcount_visitor::visit_enter(ir_dereference_array *ir)
 {
    /* It could also be a vector or a matrix.  Individual elements of vectors
     * are natrices are not tracked, so bail.
     */
    if (!ir->array->type->is_array())
       return visit_continue;

    /* If this array dereference is a child of an array dereference that was
     * already visited, just continue on.  Otherwise, for an arrays-of-arrays
     * dereference like x[1][2][3][4], we'd process the [1][2][3][4] sequence,
     * the [1][2][3] sequence, the [1][2] sequence, and the [1] sequence.  This
     * ensures that we only process the full sequence.
     */
    if (last_array_deref && last_array_deref->array == ir) {
       last_array_deref = ir;
       return visit_continue;
    }

    last_array_deref = ir;

    num_derefs = 0;

    ir_rvalue *rv = ir;
    while (rv->ir_type == ir_type_dereference_array) {
       ir_dereference_array *const deref = rv->as_dereference_array();

       assert(deref != NULL);
       assert(deref->array->type->is_array());

       ir_rvalue *const array = deref->array;
       const ir_constant *const idx = deref->array_index->as_constant();
       array_deref_range *const dr = get_array_deref();

       dr->size = array->type->array_size();

       if (idx != NULL) {
          dr->index = idx->get_int_component(0);
       } else {
          /* An unsized array can occur at the end of an SSBO.  We can't track
           * accesses to such an array, so bail.
           */
          if (array->type->array_size() == 0)
             return visit_continue;

          dr->index = dr->size;
       }

       rv = array;
    }

    ir_dereference_variable *const var_deref = rv->as_dereference_variable();

    /* If the array being dereferenced is not a variable, bail.  At the very
     * least, ir_constant and ir_dereference_record are possible.
     */
    if (var_deref == NULL)
       return visit_continue;

    ir_array_refcount_entry *const entry =
       this->get_variable_entry(var_deref->var);

    if (entry == NULL)
       return visit_stop;

    entry->mark_array_elements_referenced(derefs, num_derefs);

    return visit_continue;
 }


 ir_visitor_status
 ir_array_refcount_visitor::visit(ir_dereference_variable *ir)
 {
    ir_variable *const var = ir->variable_referenced();
    ir_array_refcount_entry *entry = this->get_variable_entry(var);

    entry->is_referenced = true;

    return visit_continue;
 }


 ir_visitor_status
 ir_array_refcount_visitor::visit_enter(ir_function_signature *ir)
 {
    /* We don't want to descend into the function parameters and
     * dead-code eliminate them, so just accept the body here.
     */
    visit_list_elements(this, &ir->body);
    return visit_continue_with_parent;
 }
	/*
	* Copyright © 2016 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_array_refcount.cpp
	*
	* Provides a visitor which produces a list of variables referenced.
	*/

	#include "ir.h"
	#include "ir_visitor.h"
	#include "ir_array_refcount.h"
	#include "compiler/glsl_types.h"
	#include "util/hash_table.h"

	ir_array_refcount_visitor::ir_array_refcount_visitor()
	: last_array_deref(0), derefs(0), num_derefs(0), derefs_size(0)
	{
	this->mem_ctx = ralloc_context(NULL);
	this->ht = _mesa_pointer_hash_table_create(NULL);
	}

	static void
	free_entry(struct hash_entry *entry)
	{
	ir_array_refcount_entry ivre = (ir_array_refcount_entry ) entry->data;
	delete ivre;
	}

	ir_array_refcount_visitor::~ir_array_refcount_visitor()
	{
	ralloc_free(this->mem_ctx);
	_mesa_hash_table_destroy(this->ht, free_entry);
	}

	ir_array_refcount_entry::ir_array_refcount_entry(ir_variable *var)
	: var(var), is_referenced(false)
	{
	num_bits = MAX2(1, var->type->arrays_of_arrays_size());
	bits = new BITSET_WORD[BITSET_WORDS(num_bits)];
	memset(bits, 0, BITSET_WORDS(num_bits) * sizeof(bits[0]));

	/* Count the "depth" of the arrays-of-arrays. */
	array_depth = 0;
	for (const glsl_type *type = var->type;
	type->is_array();
	type = type->fields.array) {
	array_depth++;
	}
	}


	ir_array_refcount_entry::~ir_array_refcount_entry()
	{
	delete [] bits;
	}


	void
	ir_array_refcount_entry::mark_array_elements_referenced(const array_deref_range *dr,
	unsigned count)
	{
	if (count != array_depth)
	return;

	mark_array_elements_referenced(dr, count, 1, 0);
	}

	void
	ir_array_refcount_entry::mark_array_elements_referenced(const array_deref_range *dr,
	unsigned count,
	unsigned scale,
	unsigned linearized_index)
	{
	/* Walk through the list of array dereferences in least- to
	* most-significant order. Along the way, accumulate the current
	* linearized offset and the scale factor for each array-of-.
	*/
	for (unsigned i = 0; i < count; i++) {
	if (dr[i].index < dr[i].size) {
	linearized_index += dr[i].index * scale;
	scale *= dr[i].size;
	} else {
	/* For each element in the current array, update the count and
	* offset, then recurse to process the remaining arrays.
	*
	* There is some inefficency here if the last element in the
	* array_deref_range list specifies the entire array. In that case,
	* the loop will make recursive calls with count == 0. In the call,
	* all that will happen is the bit will be set.
	*/
	for (unsigned j = 0; j < dr[i].size; j++) {
	mark_array_elements_referenced(&dr[i + 1],
	count - (i + 1),
	scale * dr[i].size,
	linearized_index + (j * scale));
	}

	return;
	}
	}

	BITSET_SET(bits, linearized_index);
	}

	ir_array_refcount_entry *
	ir_array_refcount_visitor::get_variable_entry(ir_variable *var)
	{
	assert(var);

	struct hash_entry *e = _mesa_hash_table_search(this->ht, var);
	if (e)
	return (ir_array_refcount_entry *)e->data;

	ir_array_refcount_entry *entry = new ir_array_refcount_entry(var);
	_mesa_hash_table_insert(this->ht, var, entry);

	return entry;
	}


	array_deref_range *
	ir_array_refcount_visitor::get_array_deref()
	{
	if ((num_derefs + 1) * sizeof(array_deref_range) > derefs_size) {
	void *ptr = reralloc_size(mem_ctx, derefs, derefs_size + 4096);

	if (ptr == NULL)
	return NULL;

	derefs_size += 4096;
	derefs = (array_deref_range *)ptr;
	}

	array_deref_range *d = &derefs[num_derefs];
	num_derefs++;

	return d;
	}

	ir_visitor_status
	ir_array_refcount_visitor::visit_enter(ir_dereference_array *ir)
	{
	/* It could also be a vector or a matrix. Individual elements of vectors
	* are natrices are not tracked, so bail.
	*/
	if (!ir->array->type->is_array())
	return visit_continue;

	/* If this array dereference is a child of an array dereference that was
	* already visited, just continue on. Otherwise, for an arrays-of-arrays
	* dereference like x[1][2][3][4], we'd process the [1][2][3][4] sequence,
	* the [1][2][3] sequence, the [1][2] sequence, and the [1] sequence. This
	* ensures that we only process the full sequence.
	*/
	if (last_array_deref && last_array_deref->array == ir) {
	last_array_deref = ir;
	return visit_continue;
	}

	last_array_deref = ir;

	num_derefs = 0;

	ir_rvalue *rv = ir;
	while (rv->ir_type == ir_type_dereference_array) {
	ir_dereference_array *const deref = rv->as_dereference_array();

	assert(deref != NULL);
	assert(deref->array->type->is_array());

	ir_rvalue *const array = deref->array;
	const ir_constant *const idx = deref->array_index->as_constant();
	array_deref_range *const dr = get_array_deref();

	dr->size = array->type->array_size();

	if (idx != NULL) {
	dr->index = idx->get_int_component(0);
	} else {
	/* An unsized array can occur at the end of an SSBO. We can't track
	* accesses to such an array, so bail.
	*/
	if (array->type->array_size() == 0)
	return visit_continue;

	dr->index = dr->size;
	}

	rv = array;
	}

	ir_dereference_variable *const var_deref = rv->as_dereference_variable();

	/* If the array being dereferenced is not a variable, bail. At the very
	* least, ir_constant and ir_dereference_record are possible.
	*/
	if (var_deref == NULL)
	return visit_continue;

	ir_array_refcount_entry *const entry =
	this->get_variable_entry(var_deref->var);

	if (entry == NULL)
	return visit_stop;

	entry->mark_array_elements_referenced(derefs, num_derefs);

	return visit_continue;
	}


	ir_visitor_status
	ir_array_refcount_visitor::visit(ir_dereference_variable *ir)
	{
	ir_variable *const var = ir->variable_referenced();
	ir_array_refcount_entry *entry = this->get_variable_entry(var);

	entry->is_referenced = true;

	return visit_continue;
	}


	ir_visitor_status
	ir_array_refcount_visitor::visit_enter(ir_function_signature *ir)
	{
	/* We don't want to descend into the function parameters and
	* dead-code eliminate them, so just accept the body here.
	*/
	visit_list_elements(this, &ir->body);
	return visit_continue_with_parent;
	}