src/glsl/lower_variable_index_to_cond_assign.cpp - platform/external/mesa3d - Git at Google

 /*
  * Copyright © 2010 Luca Barbieri
  *
  * 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 lower_variable_index_to_cond_assign.cpp
  *
  * Turns non-constant indexing into array types to a series of
  * conditional moves of each element into a temporary.
  *
  * Pre-DX10 GPUs often don't have a native way to do this operation,
  * and this works around that.
  */

 #include "ir.h"
 #include "ir_rvalue_visitor.h"
 #include "ir_optimization.h"
 #include "glsl_types.h"
 #include "main/macros.h"

 struct assignment_generator
 {
    ir_instruction* base_ir;
    ir_rvalue* array;
    bool is_write;
    ir_variable* var;

    assignment_generator()
    {
    }

    void generate(unsigned i, ir_rvalue* condition, exec_list *list) const
    {
       /* Just clone the rest of the deref chain when trying to get at the
        * underlying variable.
        */
       void *mem_ctx = hieralloc_parent(base_ir);
       ir_rvalue *element =
 	 new(mem_ctx) ir_dereference_array(this->array->clone(mem_ctx, NULL),
 					   new(mem_ctx) ir_constant(i));
       ir_rvalue *variable = new(mem_ctx) ir_dereference_variable(this->var);

       ir_assignment *assignment = (is_write)
 	 ? new(mem_ctx) ir_assignment(element, variable, condition)
 	 : new(mem_ctx) ir_assignment(variable, element, condition);

       list->push_tail(assignment);
    }
 };

 struct switch_generator
 {
    /* make TFunction a template parameter if you need to use other generators */
    typedef assignment_generator TFunction;
    const TFunction& generator;

    ir_variable* index;
    unsigned linear_sequence_max_length;
    unsigned condition_components;

    void *mem_ctx;

    switch_generator(const TFunction& generator, ir_variable *index,
 		    unsigned linear_sequence_max_length,
 		    unsigned condition_components)
       : generator(generator), index(index),
 	linear_sequence_max_length(linear_sequence_max_length),
 	condition_components(condition_components)
    {
       this->mem_ctx = hieralloc_parent(index);
    }

    void linear_sequence(unsigned begin, unsigned end, exec_list *list)
    {
       if (begin == end)
          return;

       /* If the array access is a read, read the first element of this subregion
        * unconditionally.  The remaining tests will possibly overwrite this
        * value with one of the other array elements.
        *
        * This optimization cannot be done for writes because it will cause the
        * first element of the subregion to be written possibly *in addition* to
        * one of the other elements.
        */
       unsigned first;
       if (!this->generator.is_write) {
 	 this->generator.generate(begin, 0, list);
 	 first = begin + 1;
       } else {
 	 first = begin;
       }

       for (unsigned i = first; i < end; i += 4) {
          const unsigned comps = MIN2(condition_components, end - i);

          ir_rvalue *broadcast_index =
 	    new(this->mem_ctx) ir_dereference_variable(index);

          if (comps) {
 	    const ir_swizzle_mask m = { 0, 0, 0, 0, comps, false };
 	    broadcast_index = new(this->mem_ctx) ir_swizzle(broadcast_index, m);
 	 }

 	 /* Compare the desired index value with the next block of four indices.
 	  */
          ir_constant_data test_indices_data;
          memset(&test_indices_data, 0, sizeof(test_indices_data));
          test_indices_data.i[0] = i;
          test_indices_data.i[1] = i + 1;
          test_indices_data.i[2] = i + 2;
          test_indices_data.i[3] = i + 3;
          ir_constant *const test_indices =
 	    new(this->mem_ctx) ir_constant(broadcast_index->type,
 					   &test_indices_data);

          ir_rvalue *const condition_val =
 	    new(this->mem_ctx) ir_expression(ir_binop_equal,
 					     &glsl_type::bool_type[comps - 1],
 					     broadcast_index,
 					     test_indices);

          ir_variable *const condition =
 	    new(this->mem_ctx) ir_variable(condition_val->type,
 					   "dereference_array_condition",
 					   ir_var_temporary);
          list->push_tail(condition);

 	 ir_rvalue *const cond_deref =
 	    new(this->mem_ctx) ir_dereference_variable(condition);
          list->push_tail(new(this->mem_ctx) ir_assignment(cond_deref,
 							  condition_val, 0));

          if (comps == 1) {
 	    ir_rvalue *const cond_deref =
 	       new(this->mem_ctx) ir_dereference_variable(condition);

             this->generator.generate(i, cond_deref, list);
          } else {
             for (unsigned j = 0; j < comps; j++) {
 	       ir_rvalue *const cond_deref =
 		  new(this->mem_ctx) ir_dereference_variable(condition);
 	       ir_rvalue *const cond_swiz =
 		  new(this->mem_ctx) ir_swizzle(cond_deref, j, 0, 0, 0, 1);

                this->generator.generate(i + j, cond_swiz, list);
             }
          }
       }
    }

    void bisect(unsigned begin, unsigned end, exec_list *list)
    {
       unsigned middle = (begin + end) >> 1;

       assert(index->type->is_integer());

       ir_constant *const middle_c = (index->type->base_type == GLSL_TYPE_UINT)
 	 ? new(this->mem_ctx) ir_constant((unsigned)middle)
          : new(this->mem_ctx) ir_constant((int)middle);


       ir_dereference_variable *deref =
 	 new(this->mem_ctx) ir_dereference_variable(this->index);

       ir_expression *less =
 	 new(this->mem_ctx) ir_expression(ir_binop_less, glsl_type::bool_type,
 					  deref, middle_c);

       ir_if *if_less = new(this->mem_ctx) ir_if(less);

       generate(begin, middle, &if_less->then_instructions);
       generate(middle, end, &if_less->else_instructions);

       list->push_tail(if_less);
    }

    void generate(unsigned begin, unsigned end, exec_list *list)
    {
       unsigned length = end - begin;
       if (length <= this->linear_sequence_max_length)
          return linear_sequence(begin, end, list);
       else
          return bisect(begin, end, list);
    }
 };

 /**
  * Visitor class for replacing expressions with ir_constant values.
  */

 class variable_index_to_cond_assign_visitor : public ir_rvalue_visitor {
 public:
    variable_index_to_cond_assign_visitor(bool lower_input,
 					 bool lower_output,
 					 bool lower_temp,
 					 bool lower_uniform)
    {
       this->progress = false;
       this->lower_inputs = lower_input;
       this->lower_outputs = lower_output;
       this->lower_temps = lower_temp;
       this->lower_uniforms = lower_uniform;
    }

    bool progress;
    bool lower_inputs;
    bool lower_outputs;
    bool lower_temps;
    bool lower_uniforms;

    bool is_array_or_matrix(const ir_instruction *ir) const
    {
       return (ir->type->is_array() || ir->type->is_matrix());
    }

    bool needs_lowering(ir_dereference_array *deref) const
    {
       if (deref == NULL || deref->array_index->as_constant()
 	  || !is_array_or_matrix(deref->array))
 	 return false;

       if (deref->array->ir_type == ir_type_constant)
 	 return this->lower_temps;

       const ir_variable *const var = deref->array->variable_referenced();
       switch (var->mode) {
       case ir_var_auto:
       case ir_var_temporary:
 	 return this->lower_temps;
       case ir_var_uniform:
 	 return this->lower_uniforms;
       case ir_var_in:
 	 return (var->location == -1) ? this->lower_temps : this->lower_inputs;
       case ir_var_out:
 	 return (var->location == -1) ? this->lower_temps : this->lower_outputs;
       case ir_var_inout:
 	 return this->lower_temps;
       }

       assert(!"Should not get here.");
       return false;
    }

    ir_variable *convert_dereference_array(ir_dereference_array *orig_deref,
 					  ir_rvalue* value)
    {
       assert(is_array_or_matrix(orig_deref->array));

       const unsigned length = (orig_deref->array->type->is_array())
          ? orig_deref->array->type->length
          : orig_deref->array->type->matrix_columns;

       void *const mem_ctx = hieralloc_parent(base_ir);
       ir_variable *var =
 	 new(mem_ctx) ir_variable(orig_deref->type, "dereference_array_value",
 				  ir_var_temporary);
       base_ir->insert_before(var);

       if (value) {
 	 ir_dereference *lhs = new(mem_ctx) ir_dereference_variable(var);
 	 ir_assignment *assign = new(mem_ctx) ir_assignment(lhs, value, NULL);

          base_ir->insert_before(assign);
       }

       /* Store the index to a temporary to avoid reusing its tree. */
       ir_variable *index =
 	 new(mem_ctx) ir_variable(orig_deref->array_index->type,
 				  "dereference_array_index", ir_var_temporary);
       base_ir->insert_before(index);

       ir_dereference *lhs = new(mem_ctx) ir_dereference_variable(index);
       ir_assignment *assign =
 	 new(mem_ctx) ir_assignment(lhs, orig_deref->array_index, NULL);
       base_ir->insert_before(assign);

       assignment_generator ag;
       ag.array = orig_deref->array;
       ag.base_ir = base_ir;
       ag.var = var;
       ag.is_write = !!value;

       switch_generator sg(ag, index, 4, 4);

       exec_list list;
       sg.generate(0, length, &list);
       base_ir->insert_before(&list);

       return var;
    }

    virtual void handle_rvalue(ir_rvalue **pir)
    {
       if (!*pir)
          return;

       ir_dereference_array* orig_deref = (*pir)->as_dereference_array();
       if (needs_lowering(orig_deref)) {
          ir_variable* var = convert_dereference_array(orig_deref, 0);
          assert(var);
          *pir = new(hieralloc_parent(base_ir)) ir_dereference_variable(var);
          this->progress = true;
       }
    }

    ir_visitor_status
    visit_leave(ir_assignment *ir)
    {
       ir_rvalue_visitor::visit_leave(ir);

       ir_dereference_array *orig_deref = ir->lhs->as_dereference_array();

       if (needs_lowering(orig_deref)) {
          convert_dereference_array(orig_deref, ir->rhs);
          ir->remove();
          this->progress = true;
       }

       return visit_continue;
    }
 };

 bool
 lower_variable_index_to_cond_assign(exec_list *instructions,
 				    bool lower_input,
 				    bool lower_output,
 				    bool lower_temp,
 				    bool lower_uniform)
 {
    variable_index_to_cond_assign_visitor v(lower_input,
 					   lower_output,
 					   lower_temp,
 					   lower_uniform);

    visit_list_elements(&v, instructions);

    return v.progress;
 }
	/*
	* Copyright © 2010 Luca Barbieri
	*
	* 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 lower_variable_index_to_cond_assign.cpp
	*
	* Turns non-constant indexing into array types to a series of
	* conditional moves of each element into a temporary.
	*
	* Pre-DX10 GPUs often don't have a native way to do this operation,
	* and this works around that.
	*/

	#include "ir.h"
	#include "ir_rvalue_visitor.h"
	#include "ir_optimization.h"
	#include "glsl_types.h"
	#include "main/macros.h"

	struct assignment_generator
	{
	ir_instruction* base_ir;
	ir_rvalue* array;
	bool is_write;
	ir_variable* var;

	assignment_generator()
	{
	}

	void generate(unsigned i, ir_rvalue* condition, exec_list *list) const
	{
	/* Just clone the rest of the deref chain when trying to get at the
	* underlying variable.
	*/
	void *mem_ctx = hieralloc_parent(base_ir);
	ir_rvalue *element =
	new(mem_ctx) ir_dereference_array(this->array->clone(mem_ctx, NULL),
	new(mem_ctx) ir_constant(i));
	ir_rvalue *variable = new(mem_ctx) ir_dereference_variable(this->var);

	ir_assignment *assignment = (is_write)
	? new(mem_ctx) ir_assignment(element, variable, condition)
	: new(mem_ctx) ir_assignment(variable, element, condition);

	list->push_tail(assignment);
	}
	};

	struct switch_generator
	{
	/* make TFunction a template parameter if you need to use other generators */
	typedef assignment_generator TFunction;
	const TFunction& generator;

	ir_variable* index;
	unsigned linear_sequence_max_length;
	unsigned condition_components;

	void *mem_ctx;

	switch_generator(const TFunction& generator, ir_variable *index,
	unsigned linear_sequence_max_length,
	unsigned condition_components)
	: generator(generator), index(index),
	linear_sequence_max_length(linear_sequence_max_length),
	condition_components(condition_components)
	{
	this->mem_ctx = hieralloc_parent(index);
	}

	void linear_sequence(unsigned begin, unsigned end, exec_list *list)
	{
	if (begin == end)
	return;

	/* If the array access is a read, read the first element of this subregion
	* unconditionally. The remaining tests will possibly overwrite this
	* value with one of the other array elements.
	*
	* This optimization cannot be done for writes because it will cause the
	* first element of the subregion to be written possibly in addition to
	* one of the other elements.
	*/
	unsigned first;
	if (!this->generator.is_write) {
	this->generator.generate(begin, 0, list);
	first = begin + 1;
	} else {
	first = begin;
	}

	for (unsigned i = first; i < end; i += 4) {
	const unsigned comps = MIN2(condition_components, end - i);

	ir_rvalue *broadcast_index =
	new(this->mem_ctx) ir_dereference_variable(index);

	if (comps) {
	const ir_swizzle_mask m = { 0, 0, 0, 0, comps, false };
	broadcast_index = new(this->mem_ctx) ir_swizzle(broadcast_index, m);
	}

	/* Compare the desired index value with the next block of four indices.
	*/
	ir_constant_data test_indices_data;
	memset(&test_indices_data, 0, sizeof(test_indices_data));
	test_indices_data.i[0] = i;
	test_indices_data.i[1] = i + 1;
	test_indices_data.i[2] = i + 2;
	test_indices_data.i[3] = i + 3;
	ir_constant *const test_indices =
	new(this->mem_ctx) ir_constant(broadcast_index->type,
	&test_indices_data);

	ir_rvalue *const condition_val =
	new(this->mem_ctx) ir_expression(ir_binop_equal,
	&glsl_type::bool_type[comps - 1],
	broadcast_index,
	test_indices);

	ir_variable *const condition =
	new(this->mem_ctx) ir_variable(condition_val->type,
	"dereference_array_condition",
	ir_var_temporary);
	list->push_tail(condition);

	ir_rvalue *const cond_deref =
	new(this->mem_ctx) ir_dereference_variable(condition);
	list->push_tail(new(this->mem_ctx) ir_assignment(cond_deref,
	condition_val, 0));

	if (comps == 1) {
	ir_rvalue *const cond_deref =
	new(this->mem_ctx) ir_dereference_variable(condition);

	this->generator.generate(i, cond_deref, list);
	} else {
	for (unsigned j = 0; j < comps; j++) {
	ir_rvalue *const cond_deref =
	new(this->mem_ctx) ir_dereference_variable(condition);
	ir_rvalue *const cond_swiz =
	new(this->mem_ctx) ir_swizzle(cond_deref, j, 0, 0, 0, 1);

	this->generator.generate(i + j, cond_swiz, list);
	}
	}
	}
	}

	void bisect(unsigned begin, unsigned end, exec_list *list)
	{
	unsigned middle = (begin + end) >> 1;

	assert(index->type->is_integer());

	ir_constant *const middle_c = (index->type->base_type == GLSL_TYPE_UINT)
	? new(this->mem_ctx) ir_constant((unsigned)middle)
	: new(this->mem_ctx) ir_constant((int)middle);


	ir_dereference_variable *deref =
	new(this->mem_ctx) ir_dereference_variable(this->index);

	ir_expression *less =
	new(this->mem_ctx) ir_expression(ir_binop_less, glsl_type::bool_type,
	deref, middle_c);

	ir_if *if_less = new(this->mem_ctx) ir_if(less);

	generate(begin, middle, &if_less->then_instructions);
	generate(middle, end, &if_less->else_instructions);

	list->push_tail(if_less);
	}

	void generate(unsigned begin, unsigned end, exec_list *list)
	{
	unsigned length = end - begin;
	if (length <= this->linear_sequence_max_length)
	return linear_sequence(begin, end, list);
	else
	return bisect(begin, end, list);
	}
	};

	/**
	* Visitor class for replacing expressions with ir_constant values.
	*/

	class variable_index_to_cond_assign_visitor : public ir_rvalue_visitor {
	public:
	variable_index_to_cond_assign_visitor(bool lower_input,
	bool lower_output,
	bool lower_temp,
	bool lower_uniform)
	{
	this->progress = false;
	this->lower_inputs = lower_input;
	this->lower_outputs = lower_output;
	this->lower_temps = lower_temp;
	this->lower_uniforms = lower_uniform;
	}

	bool progress;
	bool lower_inputs;
	bool lower_outputs;
	bool lower_temps;
	bool lower_uniforms;

	bool is_array_or_matrix(const ir_instruction *ir) const
	{
	return (ir->type->is_array() \|\| ir->type->is_matrix());
	}

	bool needs_lowering(ir_dereference_array *deref) const
	{
	if (deref == NULL \|\| deref->array_index->as_constant()
	\|\| !is_array_or_matrix(deref->array))
	return false;

	if (deref->array->ir_type == ir_type_constant)
	return this->lower_temps;

	const ir_variable *const var = deref->array->variable_referenced();
	switch (var->mode) {
	case ir_var_auto:
	case ir_var_temporary:
	return this->lower_temps;
	case ir_var_uniform:
	return this->lower_uniforms;
	case ir_var_in:
	return (var->location == -1) ? this->lower_temps : this->lower_inputs;
	case ir_var_out:
	return (var->location == -1) ? this->lower_temps : this->lower_outputs;
	case ir_var_inout:
	return this->lower_temps;
	}

	assert(!"Should not get here.");
	return false;
	}

	ir_variable convert_dereference_array(ir_dereference_array orig_deref,
	ir_rvalue* value)
	{
	assert(is_array_or_matrix(orig_deref->array));

	const unsigned length = (orig_deref->array->type->is_array())
	? orig_deref->array->type->length
	: orig_deref->array->type->matrix_columns;

	void *const mem_ctx = hieralloc_parent(base_ir);
	ir_variable *var =
	new(mem_ctx) ir_variable(orig_deref->type, "dereference_array_value",
	ir_var_temporary);
	base_ir->insert_before(var);

	if (value) {
	ir_dereference *lhs = new(mem_ctx) ir_dereference_variable(var);
	ir_assignment *assign = new(mem_ctx) ir_assignment(lhs, value, NULL);

	base_ir->insert_before(assign);
	}

	/* Store the index to a temporary to avoid reusing its tree. */
	ir_variable *index =
	new(mem_ctx) ir_variable(orig_deref->array_index->type,
	"dereference_array_index", ir_var_temporary);
	base_ir->insert_before(index);

	ir_dereference *lhs = new(mem_ctx) ir_dereference_variable(index);
	ir_assignment *assign =
	new(mem_ctx) ir_assignment(lhs, orig_deref->array_index, NULL);
	base_ir->insert_before(assign);

	assignment_generator ag;
	ag.array = orig_deref->array;
	ag.base_ir = base_ir;
	ag.var = var;
	ag.is_write = !!value;

	switch_generator sg(ag, index, 4, 4);

	exec_list list;
	sg.generate(0, length, &list);
	base_ir->insert_before(&list);

	return var;
	}

	virtual void handle_rvalue(ir_rvalue **pir)
	{
	if (!*pir)
	return;

	ir_dereference_array* orig_deref = (*pir)->as_dereference_array();
	if (needs_lowering(orig_deref)) {
	ir_variable* var = convert_dereference_array(orig_deref, 0);
	assert(var);
	*pir = new(hieralloc_parent(base_ir)) ir_dereference_variable(var);
	this->progress = true;
	}
	}

	ir_visitor_status
	visit_leave(ir_assignment *ir)
	{
	ir_rvalue_visitor::visit_leave(ir);

	ir_dereference_array *orig_deref = ir->lhs->as_dereference_array();

	if (needs_lowering(orig_deref)) {
	convert_dereference_array(orig_deref, ir->rhs);
	ir->remove();
	this->progress = true;
	}

	return visit_continue;
	}
	};

	bool
	lower_variable_index_to_cond_assign(exec_list *instructions,
	bool lower_input,
	bool lower_output,
	bool lower_temp,
	bool lower_uniform)
	{
	variable_index_to_cond_assign_visitor v(lower_input,
	lower_output,
	lower_temp,
	lower_uniform);

	visit_list_elements(&v, instructions);

	return v.progress;
	}