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/*
* Copyright (c) 2015 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 lower_shared_reference.cpp
*
* IR lower pass to replace dereferences of compute shader shared variables
* with intrinsic function calls.
*
* This relieves drivers of the responsibility of allocating space for the
* shared variables in the shared memory region.
*/
#include "lower_buffer_access.h"
#include "ir_builder.h"
#include "linker.h"
#include "main/macros.h"
#include "util/list.h"
#include "glsl_parser_extras.h"
#include "main/mtypes.h"
using namespace ir_builder;
namespace {
struct var_offset {
struct list_head node;
const ir_variable *var;
unsigned offset;
};
class lower_shared_reference_visitor :
public lower_buffer_access::lower_buffer_access {
public:
lower_shared_reference_visitor(struct gl_linked_shader *shader)
: list_ctx(ralloc_context(NULL)), shader(shader), shared_size(0u)
{
list_inithead(&var_offsets);
}
~lower_shared_reference_visitor()
{
ralloc_free(list_ctx);
}
enum {
shared_load_access,
shared_store_access,
shared_atomic_access,
} buffer_access_type;
void insert_buffer_access(void *mem_ctx, ir_dereference *deref,
const glsl_type *type, ir_rvalue *offset,
unsigned mask, int channel);
void handle_rvalue(ir_rvalue **rvalue);
ir_visitor_status visit_enter(ir_assignment *ir);
void handle_assignment(ir_assignment *ir);
ir_call *lower_shared_atomic_intrinsic(ir_call *ir);
ir_call *check_for_shared_atomic_intrinsic(ir_call *ir);
ir_visitor_status visit_enter(ir_call *ir);
unsigned get_shared_offset(const ir_variable *);
ir_call *shared_load(void *mem_ctx, const struct glsl_type *type,
ir_rvalue *offset);
ir_call *shared_store(void *mem_ctx, ir_rvalue *deref, ir_rvalue *offset,
unsigned write_mask);
void *list_ctx;
struct gl_linked_shader *shader;
struct list_head var_offsets;
unsigned shared_size;
bool progress;
};
unsigned
lower_shared_reference_visitor::get_shared_offset(const ir_variable *var)
{
list_for_each_entry(var_offset, var_entry, &var_offsets, node) {
if (var_entry->var == var)
return var_entry->offset;
}
struct var_offset *new_entry = rzalloc(list_ctx, struct var_offset);
list_add(&new_entry->node, &var_offsets);
new_entry->var = var;
unsigned var_align = var->type->std430_base_alignment(false);
new_entry->offset = glsl_align(shared_size, var_align);
unsigned var_size = var->type->std430_size(false);
shared_size = new_entry->offset + var_size;
return new_entry->offset;
}
void
lower_shared_reference_visitor::handle_rvalue(ir_rvalue **rvalue)
{
if (!*rvalue)
return;
ir_dereference *deref = (*rvalue)->as_dereference();
if (!deref)
return;
ir_variable *var = deref->variable_referenced();
if (!var || var->data.mode != ir_var_shader_shared)
return;
buffer_access_type = shared_load_access;
void *mem_ctx = ralloc_parent(shader->ir);
ir_rvalue *offset = NULL;
unsigned const_offset = get_shared_offset(var);
bool row_major;
const glsl_type *matrix_type;
assert(var->get_interface_type() == NULL);
const enum glsl_interface_packing packing = GLSL_INTERFACE_PACKING_STD430;
setup_buffer_access(mem_ctx, deref,
&offset, &const_offset,
&row_major, &matrix_type, NULL, packing);
/* Now that we've calculated the offset to the start of the
* dereference, walk over the type and emit loads into a temporary.
*/
const glsl_type *type = (*rvalue)->type;
ir_variable *load_var = new(mem_ctx) ir_variable(type,
"shared_load_temp",
ir_var_temporary);
base_ir->insert_before(load_var);
ir_variable *load_offset = new(mem_ctx) ir_variable(glsl_type::uint_type,
"shared_load_temp_offset",
ir_var_temporary);
base_ir->insert_before(load_offset);
base_ir->insert_before(assign(load_offset, offset));
deref = new(mem_ctx) ir_dereference_variable(load_var);
emit_access(mem_ctx, false, deref, load_offset, const_offset, row_major,
matrix_type, packing, 0);
*rvalue = deref;
progress = true;
}
void
lower_shared_reference_visitor::handle_assignment(ir_assignment *ir)
{
if (!ir || !ir->lhs)
return;
ir_rvalue *rvalue = ir->lhs->as_rvalue();
if (!rvalue)
return;
ir_dereference *deref = ir->lhs->as_dereference();
if (!deref)
return;
ir_variable *var = ir->lhs->variable_referenced();
if (!var || var->data.mode != ir_var_shader_shared)
return;
buffer_access_type = shared_store_access;
/* We have a write to a shared variable, so declare a temporary and rewrite
* the assignment so that the temporary is the LHS.
*/
void *mem_ctx = ralloc_parent(shader->ir);
const glsl_type *type = rvalue->type;
ir_variable *store_var = new(mem_ctx) ir_variable(type,
"shared_store_temp",
ir_var_temporary);
base_ir->insert_before(store_var);
ir->lhs = new(mem_ctx) ir_dereference_variable(store_var);
ir_rvalue *offset = NULL;
unsigned const_offset = get_shared_offset(var);
bool row_major;
const glsl_type *matrix_type;
assert(var->get_interface_type() == NULL);
const enum glsl_interface_packing packing = GLSL_INTERFACE_PACKING_STD430;
setup_buffer_access(mem_ctx, deref,
&offset, &const_offset,
&row_major, &matrix_type, NULL, packing);
deref = new(mem_ctx) ir_dereference_variable(store_var);
ir_variable *store_offset = new(mem_ctx) ir_variable(glsl_type::uint_type,
"shared_store_temp_offset",
ir_var_temporary);
base_ir->insert_before(store_offset);
base_ir->insert_before(assign(store_offset, offset));
/* Now we have to write the value assigned to the temporary back to memory */
emit_access(mem_ctx, true, deref, store_offset, const_offset, row_major,
matrix_type, packing, ir->write_mask);
progress = true;
}
ir_visitor_status
lower_shared_reference_visitor::visit_enter(ir_assignment *ir)
{
handle_assignment(ir);
return rvalue_visit(ir);
}
void
lower_shared_reference_visitor::insert_buffer_access(void *mem_ctx,
ir_dereference *deref,
const glsl_type *type,
ir_rvalue *offset,
unsigned mask,
int /* channel */)
{
if (buffer_access_type == shared_store_access) {
ir_call *store = shared_store(mem_ctx, deref, offset, mask);
base_ir->insert_after(store);
} else {
ir_call *load = shared_load(mem_ctx, type, offset);
base_ir->insert_before(load);
ir_rvalue *value = load->return_deref->as_rvalue()->clone(mem_ctx, NULL);
base_ir->insert_before(assign(deref->clone(mem_ctx, NULL),
value));
}
}
static bool
compute_shader_enabled(const _mesa_glsl_parse_state *state)
{
return state->stage == MESA_SHADER_COMPUTE;
}
ir_call *
lower_shared_reference_visitor::shared_store(void *mem_ctx,
ir_rvalue *deref,
ir_rvalue *offset,
unsigned write_mask)
{
exec_list sig_params;
ir_variable *offset_ref = new(mem_ctx)
ir_variable(glsl_type::uint_type, "offset" , ir_var_function_in);
sig_params.push_tail(offset_ref);
ir_variable *val_ref = new(mem_ctx)
ir_variable(deref->type, "value" , ir_var_function_in);
sig_params.push_tail(val_ref);
ir_variable *writemask_ref = new(mem_ctx)
ir_variable(glsl_type::uint_type, "write_mask" , ir_var_function_in);
sig_params.push_tail(writemask_ref);
ir_function_signature *sig = new(mem_ctx)
ir_function_signature(glsl_type::void_type, compute_shader_enabled);
assert(sig);
sig->replace_parameters(&sig_params);
sig->intrinsic_id = ir_intrinsic_shared_store;
ir_function *f = new(mem_ctx) ir_function("__intrinsic_store_shared");
f->add_signature(sig);
exec_list call_params;
call_params.push_tail(offset->clone(mem_ctx, NULL));
call_params.push_tail(deref->clone(mem_ctx, NULL));
call_params.push_tail(new(mem_ctx) ir_constant(write_mask));
return new(mem_ctx) ir_call(sig, NULL, &call_params);
}
ir_call *
lower_shared_reference_visitor::shared_load(void *mem_ctx,
const struct glsl_type *type,
ir_rvalue *offset)
{
exec_list sig_params;
ir_variable *offset_ref = new(mem_ctx)
ir_variable(glsl_type::uint_type, "offset_ref" , ir_var_function_in);
sig_params.push_tail(offset_ref);
ir_function_signature *sig =
new(mem_ctx) ir_function_signature(type, compute_shader_enabled);
assert(sig);
sig->replace_parameters(&sig_params);
sig->intrinsic_id = ir_intrinsic_shared_load;
ir_function *f = new(mem_ctx) ir_function("__intrinsic_load_shared");
f->add_signature(sig);
ir_variable *result = new(mem_ctx)
ir_variable(type, "shared_load_result", ir_var_temporary);
base_ir->insert_before(result);
ir_dereference_variable *deref_result = new(mem_ctx)
ir_dereference_variable(result);
exec_list call_params;
call_params.push_tail(offset->clone(mem_ctx, NULL));
return new(mem_ctx) ir_call(sig, deref_result, &call_params);
}
/* Lowers the intrinsic call to a new internal intrinsic that swaps the access
* to the shared variable in the first parameter by an offset. This involves
* creating the new internal intrinsic (i.e. the new function signature).
*/
ir_call *
lower_shared_reference_visitor::lower_shared_atomic_intrinsic(ir_call *ir)
{
/* Shared atomics usually have 2 parameters, the shared variable and an
* integer argument. The exception is CompSwap, that has an additional
* integer parameter.
*/
int param_count = ir->actual_parameters.length();
assert(param_count == 2 || param_count == 3);
/* First argument must be a scalar integer shared variable */
exec_node *param = ir->actual_parameters.get_head();
ir_instruction *inst = (ir_instruction *) param;
assert(inst->ir_type == ir_type_dereference_variable ||
inst->ir_type == ir_type_dereference_array ||
inst->ir_type == ir_type_dereference_record ||
inst->ir_type == ir_type_swizzle);
ir_rvalue *deref = (ir_rvalue *) inst;
assert(deref->type->is_scalar() &&
(deref->type->is_integer_32() || deref->type->is_float()));
ir_variable *var = deref->variable_referenced();
assert(var);
/* Compute the offset to the start if the dereference
*/
void *mem_ctx = ralloc_parent(shader->ir);
ir_rvalue *offset = NULL;
unsigned const_offset = get_shared_offset(var);
bool row_major;
const glsl_type *matrix_type;
assert(var->get_interface_type() == NULL);
const enum glsl_interface_packing packing = GLSL_INTERFACE_PACKING_STD430;
buffer_access_type = shared_atomic_access;
setup_buffer_access(mem_ctx, deref,
&offset, &const_offset,
&row_major, &matrix_type, NULL, packing);
assert(offset);
assert(!row_major);
assert(matrix_type == NULL);
ir_rvalue *deref_offset =
add(offset, new(mem_ctx) ir_constant(const_offset));
/* Create the new internal function signature that will take an offset
* instead of a shared variable
*/
exec_list sig_params;
ir_variable *sig_param = new(mem_ctx)
ir_variable(glsl_type::uint_type, "offset" , ir_var_function_in);
sig_params.push_tail(sig_param);
const glsl_type *type = deref->type->get_scalar_type();
sig_param = new(mem_ctx)
ir_variable(type, "data1", ir_var_function_in);
sig_params.push_tail(sig_param);
if (param_count == 3) {
sig_param = new(mem_ctx)
ir_variable(type, "data2", ir_var_function_in);
sig_params.push_tail(sig_param);
}
ir_function_signature *sig =
new(mem_ctx) ir_function_signature(deref->type,
compute_shader_enabled);
assert(sig);
sig->replace_parameters(&sig_params);
assert(ir->callee->intrinsic_id >= ir_intrinsic_generic_load);
assert(ir->callee->intrinsic_id <= ir_intrinsic_generic_atomic_comp_swap);
sig->intrinsic_id = MAP_INTRINSIC_TO_TYPE(ir->callee->intrinsic_id, shared);
char func_name[64];
sprintf(func_name, "%s_shared", ir->callee_name());
ir_function *f = new(mem_ctx) ir_function(func_name);
f->add_signature(sig);
/* Now, create the call to the internal intrinsic */
exec_list call_params;
call_params.push_tail(deref_offset);
param = ir->actual_parameters.get_head()->get_next();
ir_rvalue *param_as_rvalue = ((ir_instruction *) param)->as_rvalue();
call_params.push_tail(param_as_rvalue->clone(mem_ctx, NULL));
if (param_count == 3) {
param = param->get_next();
param_as_rvalue = ((ir_instruction *) param)->as_rvalue();
call_params.push_tail(param_as_rvalue->clone(mem_ctx, NULL));
}
ir_dereference_variable *return_deref =
ir->return_deref->clone(mem_ctx, NULL);
return new(mem_ctx) ir_call(sig, return_deref, &call_params);
}
ir_call *
lower_shared_reference_visitor::check_for_shared_atomic_intrinsic(ir_call *ir)
{
exec_list& params = ir->actual_parameters;
if (params.length() < 2 || params.length() > 3)
return ir;
ir_rvalue *rvalue =
((ir_instruction *) params.get_head())->as_rvalue();
if (!rvalue)
return ir;
ir_variable *var = rvalue->variable_referenced();
if (!var || var->data.mode != ir_var_shader_shared)
return ir;
const enum ir_intrinsic_id id = ir->callee->intrinsic_id;
if (id == ir_intrinsic_generic_atomic_add ||
id == ir_intrinsic_generic_atomic_min ||
id == ir_intrinsic_generic_atomic_max ||
id == ir_intrinsic_generic_atomic_and ||
id == ir_intrinsic_generic_atomic_or ||
id == ir_intrinsic_generic_atomic_xor ||
id == ir_intrinsic_generic_atomic_exchange ||
id == ir_intrinsic_generic_atomic_comp_swap) {
return lower_shared_atomic_intrinsic(ir);
}
return ir;
}
ir_visitor_status
lower_shared_reference_visitor::visit_enter(ir_call *ir)
{
ir_call *new_ir = check_for_shared_atomic_intrinsic(ir);
if (new_ir != ir) {
progress = true;
base_ir->replace_with(new_ir);
return visit_continue_with_parent;
}
return rvalue_visit(ir);
}
} /* unnamed namespace */
void
lower_shared_reference(struct gl_context *ctx,
struct gl_shader_program *prog,
struct gl_linked_shader *shader)
{
if (shader->Stage != MESA_SHADER_COMPUTE)
return;
lower_shared_reference_visitor v(shader);
/* Loop over the instructions lowering references, because we take a deref
* of an shared variable array using a shared variable dereference as the
* index will produce a collection of instructions all of which have cloned
* shared variable dereferences for that array index.
*/
do {
v.progress = false;
visit_list_elements(&v, shader->ir);
} while (v.progress);
prog->Comp.SharedSize = v.shared_size;
/* Section 19.1 (Compute Shader Variables) of the OpenGL 4.5 (Core Profile)
* specification says:
*
* "There is a limit to the total size of all variables declared as
* shared in a single program object. This limit, expressed in units of
* basic machine units, may be queried as the value of
* MAX_COMPUTE_SHARED_MEMORY_SIZE."
*/
if (prog->Comp.SharedSize > ctx->Const.MaxComputeSharedMemorySize) {
linker_error(prog, "Too much shared memory used (%u/%u)\n",
prog->Comp.SharedSize,
ctx->Const.MaxComputeSharedMemorySize);
}
}