[Mesa-dev] [PATCH 2/3] glsl/cs: Lower gl_GlobalInvocationID variable
Jason Ekstrand
jason at jlekstrand.net
Fri Aug 7 14:56:27 PDT 2015
Out of pure curiosity, why did you choose to do this at the GLSL IR
level? Why not pass it through to NIR and do the lowering there? Not
that you *should* do it there, but I'm curious as to what motivated
the choice. I'm honestly not sure which would have been easier.
--Jason
On Thu, Aug 6, 2015 at 11:01 AM, Jordan Justen
<jordan.l.justen at intel.com> wrote:
> We lower this based on the extension spec formula:
> gl_GlobalInvocationID =
> gl_WorkGroupID * gl_WorkGroupSize + gl_LocalInvocationID
>
> Suggested-by: Kenneth Graunke <kenneth at whitecape.org>
> Signed-off-by: Jordan Justen <jordan.l.justen at intel.com>
> ---
> src/glsl/Makefile.sources | 1 +
> src/glsl/ir_optimization.h | 1 +
> src/glsl/linker.cpp | 2 +
> src/glsl/lower_cs_global_id.cpp | 177 ++++++++++++++++++++++++++++++++++++++++
> 4 files changed, 181 insertions(+)
> create mode 100644 src/glsl/lower_cs_global_id.cpp
>
> diff --git a/src/glsl/Makefile.sources b/src/glsl/Makefile.sources
> index a0e85ed..8b1aaae 100644
> --- a/src/glsl/Makefile.sources
> +++ b/src/glsl/Makefile.sources
> @@ -144,6 +144,7 @@ LIBGLSL_FILES = \
> loop_unroll.cpp \
> lower_clip_distance.cpp \
> lower_const_arrays_to_uniforms.cpp \
> + lower_cs_global_id.cpp \
> lower_discard.cpp \
> lower_discard_flow.cpp \
> lower_if_to_cond_assign.cpp \
> diff --git a/src/glsl/ir_optimization.h b/src/glsl/ir_optimization.h
> index eef107e..7fb657c 100644
> --- a/src/glsl/ir_optimization.h
> +++ b/src/glsl/ir_optimization.h
> @@ -136,6 +136,7 @@ void optimize_dead_builtin_variables(exec_list *instructions,
> bool lower_tess_level(gl_shader *shader);
>
> bool lower_vertex_id(gl_shader *shader);
> +bool lower_cs_global_id(gl_shader *shader);
>
> bool lower_subroutine(exec_list *instructions, struct _mesa_glsl_parse_state *state);
>
> diff --git a/src/glsl/linker.cpp b/src/glsl/linker.cpp
> index e2da0af..f628198 100644
> --- a/src/glsl/linker.cpp
> +++ b/src/glsl/linker.cpp
> @@ -2153,6 +2153,8 @@ link_intrastage_shaders(void *mem_ctx,
> }
> }
>
> + lower_cs_global_id(linked);
> +
> /* Make a pass over all variable declarations to ensure that arrays with
> * unspecified sizes have a size specified. The size is inferred from the
> * max_array_access field.
> diff --git a/src/glsl/lower_cs_global_id.cpp b/src/glsl/lower_cs_global_id.cpp
> new file mode 100644
> index 0000000..606b43c
> --- /dev/null
> +++ b/src/glsl/lower_cs_global_id.cpp
> @@ -0,0 +1,177 @@
> +/*
> + * Copyright (c) 2014 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_cs_global_id.cpp
> + *
> + * We lower this based on the extension spec formula:
> + * gl_GlobalInvocationID =
> + * gl_WorkGroupID * gl_WorkGroupSize + gl_LocalInvocationID
> + */
> +
> +#include "glsl_symbol_table.h"
> +#include "ir_hierarchical_visitor.h"
> +#include "ir.h"
> +#include "ir_builder.h"
> +#include "linker.h"
> +#include "program/prog_statevars.h"
> +
> +namespace {
> +
> +class lower_cs_global_id_visitor : public ir_hierarchical_visitor {
> +public:
> + explicit lower_cs_global_id_visitor(ir_function_signature *main_sig,
> + exec_list *ir_list)
> + : progress(false), GlobalInvocationID(NULL), gl_WorkGroupID(NULL),
> + gl_WorkGroupSize(NULL), gl_LocalInvocationID(NULL),
> + main_sig(main_sig), ir_list(ir_list)
> + {
> + foreach_in_list(ir_instruction, ir, ir_list) {
> + ir_variable *const var = ir->as_variable();
> +
> + if (var == NULL)
> + continue;
> +
> + if (var->data.mode == ir_var_system_value) {
> + if (var->data.location == SYSTEM_VALUE_WORK_GROUP_ID)
> + gl_WorkGroupID = var;
> + if (var->data.location == SYSTEM_VALUE_LOCAL_INVOCATION_ID)
> + gl_LocalInvocationID = var;
> + } else if (gl_WorkGroupSize == NULL &&
> + var->data.mode == ir_var_auto &&
> + var->data.read_only &&
> + var->data.how_declared == ir_var_declared_implicitly &&
> + var->name != NULL &&
> + strcmp(var->name, "gl_WorkGroupSize") == 0) {
> + gl_WorkGroupSize = var;
> + } else
> + continue;
> + if (gl_WorkGroupID != NULL && gl_LocalInvocationID != NULL &&
> + gl_WorkGroupSize != NULL)
> + break;
> + }
> + }
> +
> + virtual ir_visitor_status visit(ir_dereference_variable *);
> +
> + bool progress;
> +
> +private:
> + ir_variable *GlobalInvocationID;
> + ir_variable *gl_WorkGroupID;
> + ir_variable *gl_WorkGroupSize;
> + ir_variable *gl_LocalInvocationID;
> +
> + ir_function_signature *main_sig;
> + exec_list *ir_list;
> +};
> +
> +} /* anonymous namespace */
> +
> +ir_visitor_status
> +lower_cs_global_id_visitor::visit(ir_dereference_variable *ir)
> +{
> + if (ir->var->data.mode != ir_var_system_value ||
> + ir->var->data.location != SYSTEM_VALUE_GLOBAL_INVOCATION_ID)
> + return visit_continue;
> +
> + if (GlobalInvocationID == NULL) {
> + const glsl_type *const uvec3_t = glsl_type::uvec3_type;
> + void *const mem_ctx = ralloc_parent(ir);
> +
> + GlobalInvocationID =
> + new(mem_ctx) ir_variable(uvec3_t, "__GlobalInvocationID",
> + ir_var_temporary);
> + ir_list->push_head(GlobalInvocationID);
> +
> + if (gl_WorkGroupID == NULL) {
> + gl_WorkGroupID = new(mem_ctx) ir_variable(uvec3_t, "gl_WorkGroupID",
> + ir_var_system_value);
> + gl_WorkGroupID->data.how_declared = ir_var_declared_implicitly;
> + gl_WorkGroupID->data.read_only = true;
> + gl_WorkGroupID->data.location = SYSTEM_VALUE_GLOBAL_INVOCATION_ID;
> + gl_WorkGroupID->data.explicit_location = true;
> + gl_WorkGroupID->data.explicit_index = 0;
> + ir_list->push_head(gl_WorkGroupID);
> + }
> +
> + if (gl_WorkGroupSize == NULL) {
> + gl_WorkGroupSize = new(mem_ctx) ir_variable(uvec3_t, "gl_WorkGroupSize",
> + ir_var_auto);
> + gl_WorkGroupSize->data.how_declared = ir_var_declared_implicitly;
> + gl_WorkGroupSize->data.read_only = true;
> + ir_list->push_head(gl_WorkGroupSize);
> + }
> +
> + if (gl_LocalInvocationID == NULL) {
> + gl_LocalInvocationID =
> + new(mem_ctx) ir_variable(uvec3_t, "gl_LocalInvocationID",
> + ir_var_system_value);
> + gl_LocalInvocationID->data.how_declared = ir_var_declared_implicitly;
> + gl_LocalInvocationID->data.read_only = true;
> + gl_LocalInvocationID->data.location = SYSTEM_VALUE_LOCAL_INVOCATION_ID;
> + gl_LocalInvocationID->data.explicit_location = true;
> + gl_LocalInvocationID->data.explicit_index = 0;
> + ir_list->push_head(gl_LocalInvocationID);
> + }
> +
> + /**
> + * gl_GlobalInvocationID =
> + * gl_WorkGroupID * gl_WorkGroupSize + gl_LocalInvocationID
> + */
> + ir_instruction *const inst =
> + ir_builder::assign(GlobalInvocationID,
> + ir_builder::add(ir_builder::mul(gl_WorkGroupID,
> + gl_WorkGroupSize),
> + gl_LocalInvocationID));
> +
> + main_sig->body.push_head(inst);
> + }
> +
> + ir->var = GlobalInvocationID;
> + progress = true;
> +
> + return visit_continue;
> +}
> +
> +bool
> +lower_cs_global_id(gl_shader *shader)
> +{
> + /* gl_GlobalInvocationID only exists in the compute shader.
> + */
> + if (shader->Stage != MESA_SHADER_COMPUTE)
> + return false;
> +
> + ir_function_signature *const main_sig =
> + link_get_main_function_signature(shader);
> + if (main_sig == NULL) {
> + assert(main_sig != NULL);
> + return false;
> + }
> +
> + lower_cs_global_id_visitor v(main_sig, shader->ir);
> +
> + v.run(shader->ir);
> +
> + return v.progress;
> +}
> --
> 2.1.4
>
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