[Mesa-dev] [PATCH 06/11] glsl: lower cull_distance into cull_distance_mesa
Marek Olšák
maraeo at gmail.com
Sun May 24 11:09:30 PDT 2015
Would it be possible to modify lower_clip_distance to add support for
cull distances instead of duplicating it?
Marek
On Sun, May 24, 2015 at 7:58 PM, Tobias Klausmann
<tobias.johannes.klausmann at mni.thm.de> wrote:
> From: Dave Airlie <airlied at redhat.com>
>
> Signed-off-by: Tobias Klausmann <tobias.johannes.klausmann at mni.thm.de>
> ---
> src/glsl/Makefile.sources | 1 +
> src/glsl/ir_optimization.h | 1 +
> src/glsl/link_varyings.cpp | 15 +-
> src/glsl/link_varyings.h | 3 +-
> src/glsl/linker.cpp | 1 +
> src/glsl/lower_cull_distance.cpp | 549 +++++++++++++++++++++++++++++++++++++++
> 6 files changed, 565 insertions(+), 5 deletions(-)
> create mode 100644 src/glsl/lower_cull_distance.cpp
>
> diff --git a/src/glsl/Makefile.sources b/src/glsl/Makefile.sources
> index d784a81..502b6ca 100644
> --- a/src/glsl/Makefile.sources
> +++ b/src/glsl/Makefile.sources
> @@ -143,6 +143,7 @@ LIBGLSL_FILES = \
> loop_unroll.cpp \
> lower_clip_distance.cpp \
> lower_const_arrays_to_uniforms.cpp \
> + lower_cull_distance.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 e6939f3..1220df6 100644
> --- a/src/glsl/ir_optimization.h
> +++ b/src/glsl/ir_optimization.h
> @@ -119,6 +119,7 @@ bool lower_variable_index_to_cond_assign(exec_list *instructions,
> bool lower_quadop_vector(exec_list *instructions, bool dont_lower_swz);
> bool lower_const_arrays_to_uniforms(exec_list *instructions);
> bool lower_clip_distance(gl_shader *shader);
> +bool lower_cull_distance(gl_shader *shader);
> void lower_output_reads(exec_list *instructions);
> bool lower_packing_builtins(exec_list *instructions, int op_mask);
> void lower_ubo_reference(struct gl_shader *shader, exec_list *instructions);
> diff --git a/src/glsl/link_varyings.cpp b/src/glsl/link_varyings.cpp
> index 7b2d4bd..46f84c6 100644
> --- a/src/glsl/link_varyings.cpp
> +++ b/src/glsl/link_varyings.cpp
> @@ -301,6 +301,7 @@ tfeedback_decl::init(struct gl_context *ctx, const void *mem_ctx,
> this->location = -1;
> this->orig_name = input;
> this->is_clip_distance_mesa = false;
> + this->is_cull_distance_mesa = false;
> this->skip_components = 0;
> this->next_buffer_separator = false;
> this->matched_candidate = NULL;
> @@ -351,6 +352,10 @@ tfeedback_decl::init(struct gl_context *ctx, const void *mem_ctx,
> strcmp(this->var_name, "gl_ClipDistance") == 0) {
> this->is_clip_distance_mesa = true;
> }
> + if (ctx->Const.ShaderCompilerOptions[MESA_SHADER_VERTEX].LowerClipDistance &&
> + strcmp(this->var_name, "gl_CullDistance") == 0) {
> + this->is_cull_distance_mesa = true;
> + }
> }
>
>
> @@ -397,7 +402,8 @@ tfeedback_decl::assign_location(struct gl_context *ctx,
> this->matched_candidate->type->fields.array->matrix_columns;
> const unsigned vector_elements =
> this->matched_candidate->type->fields.array->vector_elements;
> - unsigned actual_array_size = this->is_clip_distance_mesa ?
> + unsigned actual_array_size =
> + (this->is_clip_distance_mesa || this->is_cull_distance_mesa) ?
> prog->LastClipDistanceArraySize :
> this->matched_candidate->type->array_size();
>
> @@ -410,7 +416,8 @@ tfeedback_decl::assign_location(struct gl_context *ctx,
> actual_array_size);
> return false;
> }
> - unsigned array_elem_size = this->is_clip_distance_mesa ?
> + unsigned array_elem_size =
> + (this->is_clip_distance_mesa || this->is_cull_distance_mesa) ?
> 1 : vector_elements * matrix_cols;
> fine_location += array_elem_size * this->array_subscript;
> this->size = 1;
> @@ -419,7 +426,7 @@ tfeedback_decl::assign_location(struct gl_context *ctx,
> }
> this->vector_elements = vector_elements;
> this->matrix_columns = matrix_cols;
> - if (this->is_clip_distance_mesa)
> + if (this->is_clip_distance_mesa || this->is_cull_distance_mesa)
> this->type = GL_FLOAT;
> else
> this->type = this->matched_candidate->type->fields.array->gl_type;
> @@ -542,7 +549,7 @@ const tfeedback_candidate *
> tfeedback_decl::find_candidate(gl_shader_program *prog,
> hash_table *tfeedback_candidates)
> {
> - const char *name = this->is_clip_distance_mesa
> + const char *name = this->is_cull_distance_mesa ? "gl_CullDistanceMESA" : this->is_clip_distance_mesa
> ? "gl_ClipDistanceMESA" : this->var_name;
> this->matched_candidate = (const tfeedback_candidate *)
> hash_table_find(tfeedback_candidates, name);
> diff --git a/src/glsl/link_varyings.h b/src/glsl/link_varyings.h
> index afc16a8..842ab7c 100644
> --- a/src/glsl/link_varyings.h
> +++ b/src/glsl/link_varyings.h
> @@ -128,7 +128,7 @@ public:
> */
> unsigned num_components() const
> {
> - if (this->is_clip_distance_mesa)
> + if (this->is_clip_distance_mesa || this->is_cull_distance_mesa)
> return this->size;
> else
> return this->vector_elements * this->matrix_columns * this->size;
> @@ -165,6 +165,7 @@ private:
> * gl_ClipDistance to gl_ClipDistanceMESA.
> */
> bool is_clip_distance_mesa;
> + bool is_cull_distance_mesa;
>
> /**
> * The vertex shader output location that the linker assigned for this
> diff --git a/src/glsl/linker.cpp b/src/glsl/linker.cpp
> index 8eace14..e616520 100644
> --- a/src/glsl/linker.cpp
> +++ b/src/glsl/linker.cpp
> @@ -2938,6 +2938,7 @@ link_shaders(struct gl_context *ctx, struct gl_shader_program *prog)
>
> if (ctx->Const.ShaderCompilerOptions[i].LowerClipDistance) {
> lower_clip_distance(prog->_LinkedShaders[i]);
> + lower_cull_distance(prog->_LinkedShaders[i]);
> }
>
> while (do_common_optimization(prog->_LinkedShaders[i]->ir, true, false,
> diff --git a/src/glsl/lower_cull_distance.cpp b/src/glsl/lower_cull_distance.cpp
> new file mode 100644
> index 0000000..d3b9592
> --- /dev/null
> +++ b/src/glsl/lower_cull_distance.cpp
> @@ -0,0 +1,549 @@
> +/*
> + * Copyright © 2011 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_cull_distance.cpp
> + *
> + * This pass accounts for the difference between the way
> + * gl_CullDistance is declared in standard GLSL (as an array of
> + * floats), and the way it is frequently implemented in hardware (as
> + * a pair of vec4s, with four cull distances packed into each).
> + *
> + * The declaration of gl_CullDistance is replaced with a declaration
> + * of gl_CullDistanceMESA, and any references to gl_CullDistance are
> + * translated to refer to gl_CullDistanceMESA with the appropriate
> + * swizzling of array indices. For instance:
> + *
> + * gl_CullDistance[i]
> + *
> + * is translated into:
> + *
> + * gl_CullDistanceMESA[i>>2][i&3]
> + *
> + * Since some hardware may not internally represent gl_CullDistance as a pair
> + * of vec4's, this lowering pass is optional. To enable it, set the
> + * LowerCullDistance flag in gl_shader_compiler_options to true.
> + */
> +
> +#include "glsl_symbol_table.h"
> +#include "ir_rvalue_visitor.h"
> +#include "ir.h"
> +#include "program/prog_instruction.h" /* For WRITEMASK_* */
> +
> +namespace {
> +
> +class lower_cull_distance_visitor : public ir_rvalue_visitor {
> +public:
> + explicit lower_cull_distance_visitor(gl_shader_stage shader_stage)
> + : progress(false), old_cull_distance_1d_var(NULL),
> + old_cull_distance_2d_var(NULL), new_cull_distance_1d_var(NULL),
> + new_cull_distance_2d_var(NULL), shader_stage(shader_stage)
> + {
> + }
> +
> + virtual ir_visitor_status visit(ir_variable *);
> + void create_indices(ir_rvalue*, ir_rvalue *&, ir_rvalue *&);
> + bool is_cull_distance_vec8(ir_rvalue *ir);
> + ir_rvalue *lower_cull_distance_vec8(ir_rvalue *ir);
> + virtual ir_visitor_status visit_leave(ir_assignment *);
> + void visit_new_assignment(ir_assignment *ir);
> + virtual ir_visitor_status visit_leave(ir_call *);
> +
> + virtual void handle_rvalue(ir_rvalue **rvalue);
> +
> + void fix_lhs(ir_assignment *);
> +
> + bool progress;
> +
> + /**
> + * Pointer to the declaration of gl_CullDistance, if found.
> + *
> + * Note:
> + *
> + * - the 2d_var is for geometry shader input only.
> + *
> + * - since gl_CullDistance is available in geometry shaders as both an
> + * input and an output, it's possible for both old_cull_distance_1d_var
> + * and old_cull_distance_2d_var to be non-null.
> + */
> + ir_variable *old_cull_distance_1d_var;
> + ir_variable *old_cull_distance_2d_var;
> +
> + /**
> + * Pointer to the newly-created gl_CullDistanceMESA variable.
> + */
> + ir_variable *new_cull_distance_1d_var;
> + ir_variable *new_cull_distance_2d_var;
> +
> + /**
> + * Type of shader we are compiling (e.g. MESA_SHADER_VERTEX)
> + */
> + const gl_shader_stage shader_stage;
> +};
> +
> +} /* anonymous namespace */
> +
> +/**
> + * Replace any declaration of gl_CullDistance as an array of floats with a
> + * declaration of gl_CullDistanceMESA as an array of vec4's.
> + */
> +ir_visitor_status
> +lower_cull_distance_visitor::visit(ir_variable *ir)
> +{
> + if (!ir->name || strcmp(ir->name, "gl_CullDistance") != 0)
> + return visit_continue;
> + assert (ir->type->is_array());
> +
> + if (!ir->type->fields.array->is_array()) {
> + /* 1D gl_CullDistance (used for vertex and geometry output, and fragment
> + * input).
> + */
> + if (this->old_cull_distance_1d_var)
> + return visit_continue;
> +
> + this->progress = true;
> + this->old_cull_distance_1d_var = ir;
> + assert (ir->type->fields.array == glsl_type::float_type);
> + unsigned new_size = (ir->type->array_size() + 3) / 4;
> +
> + /* Clone the old var so that we inherit all of its properties */
> + this->new_cull_distance_1d_var = ir->clone(ralloc_parent(ir), NULL);
> +
> + /* And change the properties that we need to change */
> + this->new_cull_distance_1d_var->name
> + = ralloc_strdup(this->new_cull_distance_1d_var,
> + "gl_CullDistanceMESA");
> + this->new_cull_distance_1d_var->type
> + = glsl_type::get_array_instance(glsl_type::vec4_type, new_size);
> + this->new_cull_distance_1d_var->data.max_array_access
> + = ir->data.max_array_access / 4;
> +
> + ir->replace_with(this->new_cull_distance_1d_var);
> + } else {
> + /* 2D gl_CullDistance (used for geometry input). */
> + assert(ir->data.mode == ir_var_shader_in &&
> + this->shader_stage == MESA_SHADER_GEOMETRY);
> + if (this->old_cull_distance_2d_var)
> + return visit_continue;
> +
> + this->progress = true;
> + this->old_cull_distance_2d_var = ir;
> + assert (ir->type->fields.array->fields.array == glsl_type::float_type);
> + unsigned new_size = (ir->type->fields.array->array_size() + 3) / 4;
> +
> + /* Clone the old var so that we inherit all of its properties */
> + this->new_cull_distance_2d_var = ir->clone(ralloc_parent(ir), NULL);
> +
> + /* And change the properties that we need to change */
> + this->new_cull_distance_2d_var->name
> + = ralloc_strdup(this->new_cull_distance_2d_var, "gl_CullDistanceMESA");
> + this->new_cull_distance_2d_var->type = glsl_type::get_array_instance(
> + glsl_type::get_array_instance(glsl_type::vec4_type,
> + new_size),
> + ir->type->array_size());
> + this->new_cull_distance_2d_var->data.max_array_access
> + = ir->data.max_array_access / 4;
> +
> + ir->replace_with(this->new_cull_distance_2d_var);
> + }
> + return visit_continue;
> +}
> +
> +
> +/**
> + * Create the necessary GLSL rvalues to index into gl_CullDistanceMESA based
> + * on the rvalue previously used to index into gl_CullDistance.
> + *
> + * \param array_index Selects one of the vec4's in gl_CullDistanceMESA
> + * \param swizzle_index Selects a component within the vec4 selected by
> + * array_index.
> + */
> +void
> +lower_cull_distance_visitor::create_indices(ir_rvalue *old_index,
> + ir_rvalue *&array_index,
> + ir_rvalue *&swizzle_index)
> +{
> + void *ctx = ralloc_parent(old_index);
> +
> + /* Make sure old_index is a signed int so that the bitwise "shift" and
> + * "and" operations below type check properly.
> + */
> + if (old_index->type != glsl_type::int_type) {
> + assert (old_index->type == glsl_type::uint_type);
> + old_index = new(ctx) ir_expression(ir_unop_u2i, old_index);
> + }
> +
> + ir_constant *old_index_constant = old_index->constant_expression_value();
> + if (old_index_constant) {
> + /* gl_CullDistance is being accessed via a constant index. Don't bother
> + * creating expressions to calculate the lowered indices. Just create
> + * constants.
> + */
> + int const_val = old_index_constant->get_int_component(0);
> + array_index = new(ctx) ir_constant(const_val / 4);
> + swizzle_index = new(ctx) ir_constant(const_val % 4);
> + } else {
> + /* Create a variable to hold the value of old_index (so that we
> + * don't compute it twice).
> + */
> + ir_variable *old_index_var = new(ctx) ir_variable(
> + glsl_type::int_type, "cull_distance_index", ir_var_temporary);
> + this->base_ir->insert_before(old_index_var);
> + this->base_ir->insert_before(new(ctx) ir_assignment(
> + new(ctx) ir_dereference_variable(old_index_var), old_index));
> +
> + /* Create the expression cull_distance_index / 4. Do this as a bit
> + * shift because that's likely to be more efficient.
> + */
> + array_index = new(ctx) ir_expression(
> + ir_binop_rshift, new(ctx) ir_dereference_variable(old_index_var),
> + new(ctx) ir_constant(2));
> +
> + /* Create the expression cull_distance_index % 4. Do this as a bitwise
> + * AND because that's likely to be more efficient.
> + */
> + swizzle_index = new(ctx) ir_expression(
> + ir_binop_bit_and, new(ctx) ir_dereference_variable(old_index_var),
> + new(ctx) ir_constant(3));
> + }
> +}
> +
> +
> +/**
> + * Determine whether the given rvalue describes an array of 8 floats that
> + * needs to be lowered to an array of 2 vec4's; that is, determine whether it
> + * matches one of the following patterns:
> + *
> + * - gl_CullDistance (if gl_CullDistance is 1D)
> + * - gl_CullDistance[i] (if gl_CullDistance is 2D)
> + */
> +bool
> +lower_cull_distance_visitor::is_cull_distance_vec8(ir_rvalue *ir)
> +{
> + /* Note that geometry shaders contain gl_CullDistance both as an input
> + * (which is a 2D array) and an output (which is a 1D array), so it's
> + * possible for both this->old_cull_distance_1d_var and
> + * this->old_cull_distance_2d_var to be non-NULL in the same shader.
> + */
> +
> + if (this->old_cull_distance_1d_var) {
> + ir_dereference_variable *var_ref = ir->as_dereference_variable();
> + if (var_ref && var_ref->var == this->old_cull_distance_1d_var)
> + return true;
> + }
> + if (this->old_cull_distance_2d_var) {
> + /* 2D cull distance is only possible as a geometry input */
> + assert(this->shader_stage == MESA_SHADER_GEOMETRY);
> +
> + ir_dereference_array *array_ref = ir->as_dereference_array();
> + if (array_ref) {
> + ir_dereference_variable *var_ref =
> + array_ref->array->as_dereference_variable();
> + if (var_ref && var_ref->var == this->old_cull_distance_2d_var)
> + return true;
> + }
> + }
> + return false;
> +}
> +
> +
> +/**
> + * If the given ir satisfies is_cull_distance_vec8(), return new ir
> + * representing its lowered equivalent. That is, map:
> + *
> + * - gl_CullDistance => gl_CullDistanceMESA (if gl_CullDistance is 1D)
> + * - gl_CullDistance[i] => gl_CullDistanceMESA[i] (if gl_CullDistance is 2D)
> + *
> + * Otherwise return NULL.
> + */
> +ir_rvalue *
> +lower_cull_distance_visitor::lower_cull_distance_vec8(ir_rvalue *ir)
> +{
> + if (this->old_cull_distance_1d_var) {
> + ir_dereference_variable *var_ref = ir->as_dereference_variable();
> + if (var_ref && var_ref->var == this->old_cull_distance_1d_var) {
> + return new(ralloc_parent(ir))
> + ir_dereference_variable(this->new_cull_distance_1d_var);
> + }
> + }
> + if (this->old_cull_distance_2d_var) {
> + /* 2D cull distance is only possible as a geometry input */
> + assert(this->shader_stage == MESA_SHADER_GEOMETRY);
> +
> + ir_dereference_array *array_ref = ir->as_dereference_array();
> + if (array_ref) {
> + ir_dereference_variable *var_ref =
> + array_ref->array->as_dereference_variable();
> + if (var_ref && var_ref->var == this->old_cull_distance_2d_var) {
> + return new(ralloc_parent(ir))
> + ir_dereference_array(this->new_cull_distance_2d_var,
> + array_ref->array_index);
> + }
> + }
> + }
> + return NULL;
> +}
> +
> +
> +void
> +lower_cull_distance_visitor::handle_rvalue(ir_rvalue **rv)
> +{
> + if (*rv == NULL)
> + return;
> +
> + ir_dereference_array *const array_deref = (*rv)->as_dereference_array();
> + if (array_deref == NULL)
> + return;
> +
> + /* Replace any expression that indexes one of the floats in gl_CullDistance
> + * with an expression that indexes into one of the vec4's in
> + * gl_CullDistanceMESA and accesses the appropriate component.
> + */
> + ir_rvalue *lowered_vec8 =
> + this->lower_cull_distance_vec8(array_deref->array);
> + if (lowered_vec8 != NULL) {
> + this->progress = true;
> + ir_rvalue *array_index;
> + ir_rvalue *swizzle_index;
> + this->create_indices(array_deref->array_index, array_index, swizzle_index);
> + void *mem_ctx = ralloc_parent(array_deref);
> +
> + ir_dereference_array *const new_array_deref =
> + new(mem_ctx) ir_dereference_array(lowered_vec8, array_index);
> +
> + ir_expression *const expr =
> + new(mem_ctx) ir_expression(ir_binop_vector_extract,
> + new_array_deref,
> + swizzle_index);
> +
> + *rv = expr;
> + }
> +}
> +
> +void
> +lower_cull_distance_visitor::fix_lhs(ir_assignment *ir)
> +{
> + if (ir->lhs->ir_type == ir_type_expression) {
> + void *mem_ctx = ralloc_parent(ir);
> + ir_expression *const expr = (ir_expression *) ir->lhs;
> +
> + /* The expression must be of the form:
> + *
> + * (vector_extract gl_CullDistanceMESA[i], j).
> + */
> + assert(expr->operation == ir_binop_vector_extract);
> + assert(expr->operands[0]->ir_type == ir_type_dereference_array);
> + assert(expr->operands[0]->type == glsl_type::vec4_type);
> +
> + ir_dereference *const new_lhs = (ir_dereference *) expr->operands[0];
> + ir->rhs = new(mem_ctx) ir_expression(ir_triop_vector_insert,
> + glsl_type::vec4_type,
> + new_lhs->clone(mem_ctx, NULL),
> + ir->rhs,
> + expr->operands[1]);
> + ir->set_lhs(new_lhs);
> + ir->write_mask = WRITEMASK_XYZW;
> + }
> +}
> +
> +/**
> + * Replace any assignment having the 1D gl_CullDistance (undereferenced) as
> + * its LHS or RHS with a sequence of assignments, one for each component of
> + * the array. Each of these assignments is lowered to refer to
> + * gl_CullDistanceMESA as appropriate.
> + *
> + * We need to do a similar replacement for 2D gl_CullDistance, however since
> + * it's an input, the only case we need to address is where a 1D slice of it
> + * is the entire RHS of an assignment, e.g.:
> + *
> + * foo = gl_in[i].gl_CullDistance
> + */
> +ir_visitor_status
> +lower_cull_distance_visitor::visit_leave(ir_assignment *ir)
> +{
> + /* First invoke the base class visitor. This causes handle_rvalue() to be
> + * called on ir->rhs and ir->condition.
> + */
> + ir_rvalue_visitor::visit_leave(ir);
> +
> + if (this->is_cull_distance_vec8(ir->lhs) ||
> + this->is_cull_distance_vec8(ir->rhs)) {
> + /* LHS or RHS of the assignment is the entire 1D gl_CullDistance array
> + * (or a 1D slice of a 2D gl_CullDistance input array). Since we are
> + * reshaping gl_CullDistance from an array of floats to an array of
> + * vec4's, this isn't going to work as a bulk assignment anymore, so
> + * unroll it to element-by-element assignments and lower each of them.
> + *
> + * Note: to unroll into element-by-element assignments, we need to make
> + * clones of the LHS and RHS. This is safe because expressions and
> + * l-values are side-effect free.
> + */
> + void *ctx = ralloc_parent(ir);
> + int array_size = ir->lhs->type->array_size();
> + for (int i = 0; i < array_size; ++i) {
> + ir_dereference_array *new_lhs = new(ctx) ir_dereference_array(
> + ir->lhs->clone(ctx, NULL), new(ctx) ir_constant(i));
> + ir_dereference_array *new_rhs = new(ctx) ir_dereference_array(
> + ir->rhs->clone(ctx, NULL), new(ctx) ir_constant(i));
> + this->handle_rvalue((ir_rvalue **) &new_rhs);
> +
> + /* Handle the LHS after creating the new assignment. This must
> + * happen in this order because handle_rvalue may replace the old LHS
> + * with an ir_expression of ir_binop_vector_extract. Since this is
> + * not a valide l-value, this will cause an assertion in the
> + * ir_assignment constructor to fail.
> + *
> + * If this occurs, replace the mangled LHS with a dereference of the
> + * vector, and replace the RHS with an ir_triop_vector_insert.
> + */
> + ir_assignment *const assign = new(ctx) ir_assignment(new_lhs, new_rhs);
> + this->handle_rvalue((ir_rvalue **) &assign->lhs);
> + this->fix_lhs(assign);
> +
> + this->base_ir->insert_before(assign);
> + }
> + ir->remove();
> +
> + return visit_continue;
> + }
> +
> + /* Handle the LHS as if it were an r-value. Normally
> + * rvalue_visit(ir_assignment *) only visits the RHS, but we need to lower
> + * expressions in the LHS as well.
> + *
> + * This may cause the LHS to get replaced with an ir_expression of
> + * ir_binop_vector_extract. If this occurs, replace it with a dereference
> + * of the vector, and replace the RHS with an ir_triop_vector_insert.
> + */
> + handle_rvalue((ir_rvalue **)&ir->lhs);
> + this->fix_lhs(ir);
> +
> + return rvalue_visit(ir);
> +}
> +
> +
> +/**
> + * Set up base_ir properly and call visit_leave() on a newly created
> + * ir_assignment node. This is used in cases where we have to insert an
> + * ir_assignment in a place where we know the hierarchical visitor won't see
> + * it.
> + */
> +void
> +lower_cull_distance_visitor::visit_new_assignment(ir_assignment *ir)
> +{
> + ir_instruction *old_base_ir = this->base_ir;
> + this->base_ir = ir;
> + ir->accept(this);
> + this->base_ir = old_base_ir;
> +}
> +
> +
> +/**
> + * If a 1D gl_CullDistance variable appears as an argument in an ir_call
> + * expression, replace it with a temporary variable, and make sure the ir_call
> + * is preceded and/or followed by assignments that copy the contents of the
> + * temporary variable to and/or from gl_CullDistance. Each of these
> + * assignments is then lowered to refer to gl_CullDistanceMESA.
> + *
> + * We need to do a similar replacement for 2D gl_CullDistance, however since
> + * it's an input, the only case we need to address is where a 1D slice of it
> + * is passed as an "in" parameter to an ir_call, e.g.:
> + *
> + * foo(gl_in[i].gl_CullDistance)
> + */
> +ir_visitor_status
> +lower_cull_distance_visitor::visit_leave(ir_call *ir)
> +{
> + void *ctx = ralloc_parent(ir);
> +
> + const exec_node *formal_param_node = ir->callee->parameters.head;
> + const exec_node *actual_param_node = ir->actual_parameters.head;
> + while (!actual_param_node->is_tail_sentinel()) {
> + ir_variable *formal_param = (ir_variable *) formal_param_node;
> + ir_rvalue *actual_param = (ir_rvalue *) actual_param_node;
> +
> + /* Advance formal_param_node and actual_param_node now so that we can
> + * safely replace actual_param with another node, if necessary, below.
> + */
> + formal_param_node = formal_param_node->next;
> + actual_param_node = actual_param_node->next;
> +
> + if (this->is_cull_distance_vec8(actual_param)) {
> + /* User is trying to pass the whole 1D gl_CullDistance array (or a 1D
> + * slice of a 2D gl_CullDistance array) to a function call. Since we
> + * are reshaping gl_CullDistance from an array of floats to an array
> + * of vec4's, this isn't going to work anymore, so use a temporary
> + * array instead.
> + */
> + ir_variable *temp_cull_distance = new(ctx) ir_variable(
> + actual_param->type, "temp_cull_distance", ir_var_temporary);
> + this->base_ir->insert_before(temp_cull_distance);
> + actual_param->replace_with(
> + new(ctx) ir_dereference_variable(temp_cull_distance));
> + if (formal_param->data.mode == ir_var_function_in
> + || formal_param->data.mode == ir_var_function_inout) {
> + /* Copy from gl_CullDistance to the temporary before the call.
> + * Since we are going to insert this copy before the current
> + * instruction, we need to visit it afterwards to make sure it
> + * gets lowered.
> + */
> + ir_assignment *new_assignment = new(ctx) ir_assignment(
> + new(ctx) ir_dereference_variable(temp_cull_distance),
> + actual_param->clone(ctx, NULL));
> + this->base_ir->insert_before(new_assignment);
> + this->visit_new_assignment(new_assignment);
> + }
> + if (formal_param->data.mode == ir_var_function_out
> + || formal_param->data.mode == ir_var_function_inout) {
> + /* Copy from the temporary to gl_CullDistance after the call.
> + * Since visit_list_elements() has already decided which
> + * instruction it's going to visit next, we need to visit
> + * afterwards to make sure it gets lowered.
> + */
> + ir_assignment *new_assignment = new(ctx) ir_assignment(
> + actual_param->clone(ctx, NULL),
> + new(ctx) ir_dereference_variable(temp_cull_distance));
> + this->base_ir->insert_after(new_assignment);
> + this->visit_new_assignment(new_assignment);
> + }
> + }
> + }
> +
> + return rvalue_visit(ir);
> +}
> +
> +
> +bool
> +lower_cull_distance(gl_shader *shader)
> +{
> + lower_cull_distance_visitor v(shader->Stage);
> +
> + visit_list_elements(&v, shader->ir);
> +
> + if (v.new_cull_distance_1d_var)
> + shader->symbols->add_variable(v.new_cull_distance_1d_var);
> + if (v.new_cull_distance_2d_var)
> + shader->symbols->add_variable(v.new_cull_distance_2d_var);
> +
> + return v.progress;
> +}
> --
> 2.4.1
>
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