src/compiler/nir/nir_lower_atomics_to_ssbo.c - third_party/mesa - Git at Google

 /*
  * Copyright © 2017 Red Hat
  *
  * 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.
  *
  * Authors:
  *    Rob Clark <robclark@freedesktop.org>
  */

 #include "nir.h"
 #include "nir_builder.h"

 /*
  * Remap atomic counters to SSBOs, starting from the shader's next SSBO slot
  * (info.num_ssbos).
  */

 static nir_deref_instr *
 deref_offset_var(nir_builder *b, unsigned binding, unsigned offset_align_state)
 {
    gl_state_index16 tokens[STATE_LENGTH] = { offset_align_state, binding };
    nir_variable *var = nir_find_state_variable(b->shader, tokens);
    if (!var) {
       var = nir_state_variable_create(b->shader, glsl_uint_type(), "offset", tokens);
       var->data.how_declared = nir_var_hidden;
    }
    return nir_build_deref_var(b, var);
 }

 static bool
 lower_instr(nir_intrinsic_instr *instr, unsigned ssbo_offset, nir_builder *b, unsigned offset_align_state)
 {
    nir_intrinsic_op op = nir_intrinsic_ssbo_atomic;

    /* Initialize to something to avoid spurious compiler warning */
    nir_atomic_op atomic_op = nir_atomic_op_iadd;

    b->cursor = nir_before_instr(&instr->instr);

    switch (instr->intrinsic) {
    case nir_intrinsic_atomic_counter_inc:
    case nir_intrinsic_atomic_counter_add:
    case nir_intrinsic_atomic_counter_pre_dec:
    case nir_intrinsic_atomic_counter_post_dec:
       /* inc and dec get remapped to add: */
       atomic_op = nir_atomic_op_iadd;
       break;
    case nir_intrinsic_atomic_counter_read:
       op = nir_intrinsic_load_ssbo;
       break;
    case nir_intrinsic_atomic_counter_min:
       atomic_op = nir_atomic_op_umin;
       break;
    case nir_intrinsic_atomic_counter_max:
       atomic_op = nir_atomic_op_umax;
       break;
    case nir_intrinsic_atomic_counter_and:
       atomic_op = nir_atomic_op_iand;
       break;
    case nir_intrinsic_atomic_counter_or:
       atomic_op = nir_atomic_op_ior;
       break;
    case nir_intrinsic_atomic_counter_xor:
       atomic_op = nir_atomic_op_ixor;
       break;
    case nir_intrinsic_atomic_counter_exchange:
       atomic_op = nir_atomic_op_xchg;
       break;
    case nir_intrinsic_atomic_counter_comp_swap:
       op = nir_intrinsic_ssbo_atomic_swap;
       atomic_op = nir_atomic_op_cmpxchg;
       break;
    default:
       return false;
    }

    nir_def *buffer = nir_imm_int(b, ssbo_offset + nir_intrinsic_base(instr));
    nir_def *temp = NULL;

    nir_def *offset_load = NULL;
    if (offset_align_state) {
       nir_deref_instr *deref_offset = deref_offset_var(b, nir_intrinsic_base(instr), offset_align_state);
       offset_load = nir_load_deref(b, deref_offset);
    }
    nir_intrinsic_instr *new_instr =
       nir_intrinsic_instr_create(b->shader, op);
    if (nir_intrinsic_has_atomic_op(new_instr))
       nir_intrinsic_set_atomic_op(new_instr, atomic_op);

    /* a couple instructions need special handling since they don't map
     * 1:1 with ssbo atomics
     */
    switch (instr->intrinsic) {
    case nir_intrinsic_atomic_counter_inc:
       /* remapped to ssbo_atomic_add: { buffer_idx, offset, +1 } */
       temp = nir_imm_int(b, +1);
       new_instr->src[0] = nir_src_for_ssa(buffer);
       new_instr->src[1] = nir_src_for_ssa(instr->src[0].ssa);
       new_instr->src[2] = nir_src_for_ssa(temp);
       break;
    case nir_intrinsic_atomic_counter_pre_dec:
    case nir_intrinsic_atomic_counter_post_dec:
       /* remapped to ssbo_atomic_add: { buffer_idx, offset, -1 } */
       /* NOTE semantic difference so we adjust the return value below */
       temp = nir_imm_int(b, -1);
       new_instr->src[0] = nir_src_for_ssa(buffer);
       new_instr->src[1] = nir_src_for_ssa(instr->src[0].ssa);
       new_instr->src[2] = nir_src_for_ssa(temp);
       break;
    case nir_intrinsic_atomic_counter_read:
       /* remapped to load_ssbo: { buffer_idx, offset } */
       new_instr->src[0] = nir_src_for_ssa(buffer);
       new_instr->src[1] = nir_src_for_ssa(instr->src[0].ssa);
       break;
    default:
       /* remapped to ssbo_atomic_x: { buffer_idx, offset, data, (compare)? } */
       new_instr->src[0] = nir_src_for_ssa(buffer);
       new_instr->src[1] = nir_src_for_ssa(instr->src[0].ssa);
       new_instr->src[2] = nir_src_for_ssa(instr->src[1].ssa);
       if (op == nir_intrinsic_ssbo_atomic_swap)
          new_instr->src[3] = nir_src_for_ssa(instr->src[2].ssa);
       break;
    }

    if (offset_load)
       new_instr->src[1].ssa = nir_iadd(b, new_instr->src[1].ssa, offset_load);

    if (nir_intrinsic_range_base(instr))
       new_instr->src[1].ssa = nir_iadd(b, new_instr->src[1].ssa,
                                        nir_imm_int(b, nir_intrinsic_range_base(instr)));

    if (new_instr->intrinsic == nir_intrinsic_load_ssbo) {
       nir_intrinsic_set_align(new_instr, 4, 0);

       /* we could be replacing an intrinsic with fixed # of dest
        * num_components with one that has variable number.  So
        * best to take this from the dest:
        */
       new_instr->num_components = instr->def.num_components;
    }

    nir_def_init(&new_instr->instr, &new_instr->def,
                 instr->def.num_components, instr->def.bit_size);
    nir_instr_insert_before(&instr->instr, &new_instr->instr);
    nir_instr_remove(&instr->instr);

    if (instr->intrinsic == nir_intrinsic_atomic_counter_pre_dec) {
       b->cursor = nir_after_instr(&new_instr->instr);
       nir_def *result = nir_iadd(b, &new_instr->def, temp);
       nir_def_rewrite_uses(&instr->def, result);
    } else {
       nir_def_rewrite_uses(&instr->def, &new_instr->def);
    }

    return true;
 }

 static bool
 is_atomic_uint(const struct glsl_type *type)
 {
    if (glsl_get_base_type(type) == GLSL_TYPE_ARRAY)
       return is_atomic_uint(glsl_get_array_element(type));
    return glsl_get_base_type(type) == GLSL_TYPE_ATOMIC_UINT;
 }

 bool
 nir_lower_atomics_to_ssbo(nir_shader *shader, unsigned offset_align_state)
 {
    unsigned ssbo_offset = shader->info.num_ssbos;
    bool progress = false;

    nir_foreach_function_impl(impl, shader) {
       nir_builder builder = nir_builder_create(impl);
       nir_foreach_block(block, impl) {
          nir_foreach_instr_safe(instr, block) {
             if (instr->type == nir_instr_type_intrinsic)
                progress |= lower_instr(nir_instr_as_intrinsic(instr),
                                        ssbo_offset, &builder, offset_align_state);
          }
       }

       nir_progress(true, impl, nir_metadata_control_flow);
    }

    if (progress) {
       /* replace atomic_uint uniforms with ssbo's: */
       unsigned replaced = 0;
       nir_foreach_uniform_variable_safe(var, shader) {
          if (is_atomic_uint(var->type)) {
             exec_node_remove(&var->node);

             if (replaced & (1 << var->data.binding))
                continue;

             nir_variable *ssbo;
             char name[16];

             /* A length of 0 is used to denote unsized arrays */
             const struct glsl_type *type = glsl_array_type(glsl_uint_type(), 0, 0);

             snprintf(name, sizeof(name), "counter%d", var->data.binding);

             ssbo = nir_variable_create(shader, nir_var_mem_ssbo, type, name);
             ssbo->data.binding = ssbo_offset + var->data.binding;
             ssbo->data.explicit_binding = var->data.explicit_binding;

             /* We can't use num_abos, because it only represents the number of
              * active atomic counters, and currently unlike SSBO's they aren't
              * compacted so num_abos actually isn't a bound on the index passed
              * to nir_intrinsic_atomic_counter_*. e.g. if we have a single atomic
              * counter declared like:
              *
              * layout(binding=1) atomic_uint counter0;
              *
              * then when we lower accesses to it the atomic_counter_* intrinsics
              * will have 1 as the index but num_abos will still be 1.
              */
             shader->info.num_ssbos = MAX2(shader->info.num_ssbos,
                                           ssbo->data.binding + 1);

             struct glsl_struct_field field = {
                .type = type,
                .name = "counters",
                .location = -1,
             };

             ssbo->interface_type =
                glsl_interface_type(&field, 1, GLSL_INTERFACE_PACKING_STD430,
                                    false, "counters");

             replaced |= (1 << var->data.binding);
          }
       }

       shader->info.num_abos = 0;
    }

    return progress;
 }
	/*
	* Copyright © 2017 Red Hat
	*
	* 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.
	*
	* Authors:
	* Rob Clark <robclark@freedesktop.org>
	*/

	#include "nir.h"
	#include "nir_builder.h"

	/*
	* Remap atomic counters to SSBOs, starting from the shader's next SSBO slot
	* (info.num_ssbos).
	*/

	static nir_deref_instr *
	deref_offset_var(nir_builder *b, unsigned binding, unsigned offset_align_state)
	{
	gl_state_index16 tokens[STATE_LENGTH] = { offset_align_state, binding };
	nir_variable *var = nir_find_state_variable(b->shader, tokens);
	if (!var) {
	var = nir_state_variable_create(b->shader, glsl_uint_type(), "offset", tokens);
	var->data.how_declared = nir_var_hidden;
	}
	return nir_build_deref_var(b, var);
	}

	static bool
	lower_instr(nir_intrinsic_instr instr, unsigned ssbo_offset, nir_builder b, unsigned offset_align_state)
	{
	nir_intrinsic_op op = nir_intrinsic_ssbo_atomic;

	/* Initialize to something to avoid spurious compiler warning */
	nir_atomic_op atomic_op = nir_atomic_op_iadd;

	b->cursor = nir_before_instr(&instr->instr);

	switch (instr->intrinsic) {
	case nir_intrinsic_atomic_counter_inc:
	case nir_intrinsic_atomic_counter_add:
	case nir_intrinsic_atomic_counter_pre_dec:
	case nir_intrinsic_atomic_counter_post_dec:
	/* inc and dec get remapped to add: */
	atomic_op = nir_atomic_op_iadd;
	break;
	case nir_intrinsic_atomic_counter_read:
	op = nir_intrinsic_load_ssbo;
	break;
	case nir_intrinsic_atomic_counter_min:
	atomic_op = nir_atomic_op_umin;
	break;
	case nir_intrinsic_atomic_counter_max:
	atomic_op = nir_atomic_op_umax;
	break;
	case nir_intrinsic_atomic_counter_and:
	atomic_op = nir_atomic_op_iand;
	break;
	case nir_intrinsic_atomic_counter_or:
	atomic_op = nir_atomic_op_ior;
	break;
	case nir_intrinsic_atomic_counter_xor:
	atomic_op = nir_atomic_op_ixor;
	break;
	case nir_intrinsic_atomic_counter_exchange:
	atomic_op = nir_atomic_op_xchg;
	break;
	case nir_intrinsic_atomic_counter_comp_swap:
	op = nir_intrinsic_ssbo_atomic_swap;
	atomic_op = nir_atomic_op_cmpxchg;
	break;
	default:
	return false;
	}

	nir_def *buffer = nir_imm_int(b, ssbo_offset + nir_intrinsic_base(instr));
	nir_def *temp = NULL;

	nir_def *offset_load = NULL;
	if (offset_align_state) {
	nir_deref_instr *deref_offset = deref_offset_var(b, nir_intrinsic_base(instr), offset_align_state);
	offset_load = nir_load_deref(b, deref_offset);
	}
	nir_intrinsic_instr *new_instr =
	nir_intrinsic_instr_create(b->shader, op);
	if (nir_intrinsic_has_atomic_op(new_instr))
	nir_intrinsic_set_atomic_op(new_instr, atomic_op);

	/* a couple instructions need special handling since they don't map
	* 1:1 with ssbo atomics
	*/
	switch (instr->intrinsic) {
	case nir_intrinsic_atomic_counter_inc:
	/* remapped to ssbo_atomic_add: { buffer_idx, offset, +1 } */
	temp = nir_imm_int(b, +1);
	new_instr->src[0] = nir_src_for_ssa(buffer);
	new_instr->src[1] = nir_src_for_ssa(instr->src[0].ssa);
	new_instr->src[2] = nir_src_for_ssa(temp);
	break;
	case nir_intrinsic_atomic_counter_pre_dec:
	case nir_intrinsic_atomic_counter_post_dec:
	/* remapped to ssbo_atomic_add: { buffer_idx, offset, -1 } */
	/* NOTE semantic difference so we adjust the return value below */
	temp = nir_imm_int(b, -1);
	new_instr->src[0] = nir_src_for_ssa(buffer);
	new_instr->src[1] = nir_src_for_ssa(instr->src[0].ssa);
	new_instr->src[2] = nir_src_for_ssa(temp);
	break;
	case nir_intrinsic_atomic_counter_read:
	/* remapped to load_ssbo: { buffer_idx, offset } */
	new_instr->src[0] = nir_src_for_ssa(buffer);
	new_instr->src[1] = nir_src_for_ssa(instr->src[0].ssa);
	break;
	default:
	/* remapped to ssbo_atomic_x: { buffer_idx, offset, data, (compare)? } */
	new_instr->src[0] = nir_src_for_ssa(buffer);
	new_instr->src[1] = nir_src_for_ssa(instr->src[0].ssa);
	new_instr->src[2] = nir_src_for_ssa(instr->src[1].ssa);
	if (op == nir_intrinsic_ssbo_atomic_swap)
	new_instr->src[3] = nir_src_for_ssa(instr->src[2].ssa);
	break;
	}

	if (offset_load)
	new_instr->src[1].ssa = nir_iadd(b, new_instr->src[1].ssa, offset_load);

	if (nir_intrinsic_range_base(instr))
	new_instr->src[1].ssa = nir_iadd(b, new_instr->src[1].ssa,
	nir_imm_int(b, nir_intrinsic_range_base(instr)));

	if (new_instr->intrinsic == nir_intrinsic_load_ssbo) {
	nir_intrinsic_set_align(new_instr, 4, 0);

	/* we could be replacing an intrinsic with fixed # of dest
	* num_components with one that has variable number. So
	* best to take this from the dest:
	*/
	new_instr->num_components = instr->def.num_components;
	}

	nir_def_init(&new_instr->instr, &new_instr->def,
	instr->def.num_components, instr->def.bit_size);
	nir_instr_insert_before(&instr->instr, &new_instr->instr);
	nir_instr_remove(&instr->instr);

	if (instr->intrinsic == nir_intrinsic_atomic_counter_pre_dec) {
	b->cursor = nir_after_instr(&new_instr->instr);
	nir_def *result = nir_iadd(b, &new_instr->def, temp);
	nir_def_rewrite_uses(&instr->def, result);
	} else {
	nir_def_rewrite_uses(&instr->def, &new_instr->def);
	}

	return true;
	}

	static bool
	is_atomic_uint(const struct glsl_type *type)
	{
	if (glsl_get_base_type(type) == GLSL_TYPE_ARRAY)
	return is_atomic_uint(glsl_get_array_element(type));
	return glsl_get_base_type(type) == GLSL_TYPE_ATOMIC_UINT;
	}

	bool
	nir_lower_atomics_to_ssbo(nir_shader *shader, unsigned offset_align_state)
	{
	unsigned ssbo_offset = shader->info.num_ssbos;
	bool progress = false;

	nir_foreach_function_impl(impl, shader) {
	nir_builder builder = nir_builder_create(impl);
	nir_foreach_block(block, impl) {
	nir_foreach_instr_safe(instr, block) {
	if (instr->type == nir_instr_type_intrinsic)
	progress \|= lower_instr(nir_instr_as_intrinsic(instr),
	ssbo_offset, &builder, offset_align_state);
	}
	}

	nir_progress(true, impl, nir_metadata_control_flow);
	}

	if (progress) {
	/* replace atomic_uint uniforms with ssbo's: */
	unsigned replaced = 0;
	nir_foreach_uniform_variable_safe(var, shader) {
	if (is_atomic_uint(var->type)) {
	exec_node_remove(&var->node);

	if (replaced & (1 << var->data.binding))
	continue;

	nir_variable *ssbo;
	char name[16];

	/* A length of 0 is used to denote unsized arrays */
	const struct glsl_type *type = glsl_array_type(glsl_uint_type(), 0, 0);

	snprintf(name, sizeof(name), "counter%d", var->data.binding);

	ssbo = nir_variable_create(shader, nir_var_mem_ssbo, type, name);
	ssbo->data.binding = ssbo_offset + var->data.binding;
	ssbo->data.explicit_binding = var->data.explicit_binding;

	/* We can't use num_abos, because it only represents the number of
	* active atomic counters, and currently unlike SSBO's they aren't
	* compacted so num_abos actually isn't a bound on the index passed
	* to nir_intrinsic_atomic_counter_*. e.g. if we have a single atomic
	* counter declared like:
	*
	* layout(binding=1) atomic_uint counter0;
	*
	* then when we lower accesses to it the atomic_counter_* intrinsics
	* will have 1 as the index but num_abos will still be 1.
	*/
	shader->info.num_ssbos = MAX2(shader->info.num_ssbos,
	ssbo->data.binding + 1);

	struct glsl_struct_field field = {
	.type = type,
	.name = "counters",
	.location = -1,
	};

	ssbo->interface_type =
	glsl_interface_type(&field, 1, GLSL_INTERFACE_PACKING_STD430,
	false, "counters");

	replaced \|= (1 << var->data.binding);
	}
	}

	shader->info.num_abos = 0;
	}

	return progress;
	}