[Mesa-dev] [PATCH v3 04/11] glsl: rename lower_clip_distance to lower_distance.
Tobias Klausmann
tobias.johannes.klausmann at mni.thm.de
Sun May 8 20:44:04 UTC 2016
From: Dave Airlie <airlied at redhat.com>
This just renames the file in anticipation of adding cull lowering.
Signed-off-by: Tobias Klausmann <tobias.johannes.klausmann at mni.thm.de>
Signed-off-by: Dave Airlie <airlied at redhat.com>
Reviewed-by: Edward O'Callaghan <eocallaghan at alterapraxis.com>
---
src/compiler/Makefile.sources | 2 +-
src/compiler/glsl/lower_clip_distance.cpp | 574 ------------------------------
src/compiler/glsl/lower_distance.cpp | 574 ++++++++++++++++++++++++++++++
3 files changed, 575 insertions(+), 575 deletions(-)
delete mode 100644 src/compiler/glsl/lower_clip_distance.cpp
create mode 100644 src/compiler/glsl/lower_distance.cpp
diff --git a/src/compiler/Makefile.sources b/src/compiler/Makefile.sources
index 2a52319..a46d7ca 100644
--- a/src/compiler/Makefile.sources
+++ b/src/compiler/Makefile.sources
@@ -77,10 +77,10 @@ LIBGLSL_FILES = \
glsl/loop_unroll.cpp \
glsl/lower_buffer_access.cpp \
glsl/lower_buffer_access.h \
- glsl/lower_clip_distance.cpp \
glsl/lower_const_arrays_to_uniforms.cpp \
glsl/lower_discard.cpp \
glsl/lower_discard_flow.cpp \
+ glsl/lower_distance.cpp \
glsl/lower_if_to_cond_assign.cpp \
glsl/lower_instructions.cpp \
glsl/lower_jumps.cpp \
diff --git a/src/compiler/glsl/lower_clip_distance.cpp b/src/compiler/glsl/lower_clip_distance.cpp
deleted file mode 100644
index 5d9468d..0000000
--- a/src/compiler/glsl/lower_clip_distance.cpp
+++ /dev/null
@@ -1,574 +0,0 @@
-/*
- * 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_clip_distance.cpp
- *
- * This pass accounts for the difference between the way
- * gl_ClipDistance 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 clip distances packed into each).
- *
- * The declaration of gl_ClipDistance is replaced with a declaration
- * of gl_ClipDistanceMESA, and any references to gl_ClipDistance are
- * translated to refer to gl_ClipDistanceMESA with the appropriate
- * swizzling of array indices. For instance:
- *
- * gl_ClipDistance[i]
- *
- * is translated into:
- *
- * gl_ClipDistanceMESA[i>>2][i&3]
- *
- * Since some hardware may not internally represent gl_ClipDistance as a pair
- * of vec4's, this lowering pass is optional. To enable it, set the
- * LowerCombinedClipCullDistance 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_clip_distance_visitor : public ir_rvalue_visitor {
-public:
- explicit lower_clip_distance_visitor(gl_shader_stage shader_stage)
- : progress(false), old_clip_distance_out_var(NULL),
- old_clip_distance_in_var(NULL), new_clip_distance_out_var(NULL),
- new_clip_distance_in_var(NULL), shader_stage(shader_stage)
- {
- }
-
- virtual ir_visitor_status visit(ir_variable *);
- void create_indices(ir_rvalue*, ir_rvalue *&, ir_rvalue *&);
- bool is_clip_distance_vec8(ir_rvalue *ir);
- ir_rvalue *lower_clip_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_ClipDistance, if found.
- *
- * Note:
- *
- * - the in_var is for geometry and both tessellation shader inputs only.
- *
- * - since gl_ClipDistance is available in tessellation control,
- * tessellation evaluation and geometry shaders as both an input
- * and an output, it's possible for both old_clip_distance_out_var
- * and old_clip_distance_in_var to be non-null.
- */
- ir_variable *old_clip_distance_out_var;
- ir_variable *old_clip_distance_in_var;
-
- /**
- * Pointer to the newly-created gl_ClipDistanceMESA variable.
- */
- ir_variable *new_clip_distance_out_var;
- ir_variable *new_clip_distance_in_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_ClipDistance as an array of floats with a
- * declaration of gl_ClipDistanceMESA as an array of vec4's.
- */
-ir_visitor_status
-lower_clip_distance_visitor::visit(ir_variable *ir)
-{
- ir_variable **old_var;
- ir_variable **new_var;
-
- if (!ir->name || strcmp(ir->name, "gl_ClipDistance") != 0)
- return visit_continue;
- assert (ir->type->is_array());
-
- if (ir->data.mode == ir_var_shader_out) {
- if (this->old_clip_distance_out_var)
- return visit_continue;
- old_var = &old_clip_distance_out_var;
- new_var = &new_clip_distance_out_var;
- } else if (ir->data.mode == ir_var_shader_in) {
- if (this->old_clip_distance_in_var)
- return visit_continue;
- old_var = &old_clip_distance_in_var;
- new_var = &new_clip_distance_in_var;
- } else {
- unreachable("not reached");
- }
-
- this->progress = true;
-
- if (!ir->type->fields.array->is_array()) {
- /* gl_ClipDistance (used for vertex, tessellation evaluation and
- * geometry output, and fragment input).
- */
- assert((ir->data.mode == ir_var_shader_in &&
- this->shader_stage == MESA_SHADER_FRAGMENT) ||
- (ir->data.mode == ir_var_shader_out &&
- (this->shader_stage == MESA_SHADER_VERTEX ||
- this->shader_stage == MESA_SHADER_TESS_EVAL ||
- this->shader_stage == MESA_SHADER_GEOMETRY)));
-
- *old_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 */
- *new_var = ir->clone(ralloc_parent(ir), NULL);
-
- /* And change the properties that we need to change */
- (*new_var)->name = ralloc_strdup(*new_var, "gl_ClipDistanceMESA");
- (*new_var)->type = glsl_type::get_array_instance(glsl_type::vec4_type,
- new_size);
- (*new_var)->data.max_array_access = ir->data.max_array_access / 4;
-
- ir->replace_with(*new_var);
- } else {
- /* 2D gl_ClipDistance (used for tessellation control, tessellation
- * evaluation and geometry input, and tessellation control output).
- */
- assert((ir->data.mode == ir_var_shader_in &&
- (this->shader_stage == MESA_SHADER_GEOMETRY ||
- this->shader_stage == MESA_SHADER_TESS_EVAL)) ||
- this->shader_stage == MESA_SHADER_TESS_CTRL);
-
- *old_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 */
- *new_var = ir->clone(ralloc_parent(ir), NULL);
-
- /* And change the properties that we need to change */
- (*new_var)->name = ralloc_strdup(*new_var, "gl_ClipDistanceMESA");
- (*new_var)->type = glsl_type::get_array_instance(
- glsl_type::get_array_instance(glsl_type::vec4_type,
- new_size),
- ir->type->array_size());
- (*new_var)->data.max_array_access = ir->data.max_array_access / 4;
-
- ir->replace_with(*new_var);
- }
-
- return visit_continue;
-}
-
-
-/**
- * Create the necessary GLSL rvalues to index into gl_ClipDistanceMESA based
- * on the rvalue previously used to index into gl_ClipDistance.
- *
- * \param array_index Selects one of the vec4's in gl_ClipDistanceMESA
- * \param swizzle_index Selects a component within the vec4 selected by
- * array_index.
- */
-void
-lower_clip_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_ClipDistance 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, "clip_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 clip_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 clip_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_ClipDistance (if gl_ClipDistance is 1D)
- * - gl_ClipDistance[i] (if gl_ClipDistance is 2D)
- */
-bool
-lower_clip_distance_visitor::is_clip_distance_vec8(ir_rvalue *ir)
-{
- /* Note that geometry shaders contain gl_ClipDistance 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_clip_distance_out_var and
- * this->old_clip_distance_in_var to be non-NULL in the same shader.
- */
-
- if (!ir->type->is_array())
- return false;
- if (ir->type->fields.array != glsl_type::float_type)
- return false;
-
- if (this->old_clip_distance_out_var) {
- if (ir->variable_referenced() == this->old_clip_distance_out_var)
- return true;
- }
- if (this->old_clip_distance_in_var) {
- assert(this->shader_stage == MESA_SHADER_TESS_CTRL ||
- this->shader_stage == MESA_SHADER_TESS_EVAL ||
- this->shader_stage == MESA_SHADER_GEOMETRY ||
- this->shader_stage == MESA_SHADER_FRAGMENT);
-
- if (ir->variable_referenced() == this->old_clip_distance_in_var)
- return true;
- }
- return false;
-}
-
-
-/**
- * If the given ir satisfies is_clip_distance_vec8(), return new ir
- * representing its lowered equivalent. That is, map:
- *
- * - gl_ClipDistance => gl_ClipDistanceMESA (if gl_ClipDistance is 1D)
- * - gl_ClipDistance[i] => gl_ClipDistanceMESA[i] (if gl_ClipDistance is 2D)
- *
- * Otherwise return NULL.
- */
-ir_rvalue *
-lower_clip_distance_visitor::lower_clip_distance_vec8(ir_rvalue *ir)
-{
- if (!ir->type->is_array())
- return NULL;
- if (ir->type->fields.array != glsl_type::float_type)
- return NULL;
-
- ir_variable **new_var = NULL;
- if (this->old_clip_distance_out_var) {
- if (ir->variable_referenced() == this->old_clip_distance_out_var)
- new_var = &this->new_clip_distance_out_var;
- }
- if (this->old_clip_distance_in_var) {
- if (ir->variable_referenced() == this->old_clip_distance_in_var)
- new_var = &this->new_clip_distance_in_var;
- }
- if (new_var == NULL)
- return NULL;
-
- if (ir->as_dereference_variable()) {
- return new(ralloc_parent(ir)) ir_dereference_variable(*new_var);
- } else {
- ir_dereference_array *array_ref = ir->as_dereference_array();
- assert(array_ref);
- assert(array_ref->array->as_dereference_variable());
-
- return new(ralloc_parent(ir))
- ir_dereference_array(*new_var, array_ref->array_index);
- }
-}
-
-
-void
-lower_clip_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_ClipDistance
- * with an expression that indexes into one of the vec4's in
- * gl_ClipDistanceMESA and accesses the appropriate component.
- */
- ir_rvalue *lowered_vec8 =
- this->lower_clip_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_clip_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_ClipDistanceMESA[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_ClipDistance (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_ClipDistanceMESA as appropriate.
- *
- * We need to do a similar replacement for 2D gl_ClipDistance, 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_ClipDistance
- */
-ir_visitor_status
-lower_clip_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_clip_distance_vec8(ir->lhs) ||
- this->is_clip_distance_vec8(ir->rhs)) {
- /* LHS or RHS of the assignment is the entire 1D gl_ClipDistance array
- * (or a 1D slice of a 2D gl_ClipDistance input array). Since we are
- * reshaping gl_ClipDistance 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_clip_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_ClipDistance 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_ClipDistance. Each of these
- * assignments is then lowered to refer to gl_ClipDistanceMESA.
- *
- * We need to do a similar replacement for 2D gl_ClipDistance, 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_ClipDistance)
- */
-ir_visitor_status
-lower_clip_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_clip_distance_vec8(actual_param)) {
- /* User is trying to pass the whole 1D gl_ClipDistance array (or a 1D
- * slice of a 2D gl_ClipDistance array) to a function call. Since we
- * are reshaping gl_ClipDistance 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_clip_distance = new(ctx) ir_variable(
- actual_param->type, "temp_clip_distance", ir_var_temporary);
- this->base_ir->insert_before(temp_clip_distance);
- actual_param->replace_with(
- new(ctx) ir_dereference_variable(temp_clip_distance));
- if (formal_param->data.mode == ir_var_function_in
- || formal_param->data.mode == ir_var_function_inout) {
- /* Copy from gl_ClipDistance 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_clip_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_ClipDistance 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_clip_distance));
- this->base_ir->insert_after(new_assignment);
- this->visit_new_assignment(new_assignment);
- }
- }
- }
-
- return rvalue_visit(ir);
-}
-
-
-bool
-lower_clip_distance(gl_shader *shader)
-{
- lower_clip_distance_visitor v(shader->Stage);
-
- visit_list_elements(&v, shader->ir);
-
- if (v.new_clip_distance_out_var)
- shader->symbols->add_variable(v.new_clip_distance_out_var);
- if (v.new_clip_distance_in_var)
- shader->symbols->add_variable(v.new_clip_distance_in_var);
-
- return v.progress;
-}
diff --git a/src/compiler/glsl/lower_distance.cpp b/src/compiler/glsl/lower_distance.cpp
new file mode 100644
index 0000000..5d9468d
--- /dev/null
+++ b/src/compiler/glsl/lower_distance.cpp
@@ -0,0 +1,574 @@
+/*
+ * 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_clip_distance.cpp
+ *
+ * This pass accounts for the difference between the way
+ * gl_ClipDistance 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 clip distances packed into each).
+ *
+ * The declaration of gl_ClipDistance is replaced with a declaration
+ * of gl_ClipDistanceMESA, and any references to gl_ClipDistance are
+ * translated to refer to gl_ClipDistanceMESA with the appropriate
+ * swizzling of array indices. For instance:
+ *
+ * gl_ClipDistance[i]
+ *
+ * is translated into:
+ *
+ * gl_ClipDistanceMESA[i>>2][i&3]
+ *
+ * Since some hardware may not internally represent gl_ClipDistance as a pair
+ * of vec4's, this lowering pass is optional. To enable it, set the
+ * LowerCombinedClipCullDistance 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_clip_distance_visitor : public ir_rvalue_visitor {
+public:
+ explicit lower_clip_distance_visitor(gl_shader_stage shader_stage)
+ : progress(false), old_clip_distance_out_var(NULL),
+ old_clip_distance_in_var(NULL), new_clip_distance_out_var(NULL),
+ new_clip_distance_in_var(NULL), shader_stage(shader_stage)
+ {
+ }
+
+ virtual ir_visitor_status visit(ir_variable *);
+ void create_indices(ir_rvalue*, ir_rvalue *&, ir_rvalue *&);
+ bool is_clip_distance_vec8(ir_rvalue *ir);
+ ir_rvalue *lower_clip_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_ClipDistance, if found.
+ *
+ * Note:
+ *
+ * - the in_var is for geometry and both tessellation shader inputs only.
+ *
+ * - since gl_ClipDistance is available in tessellation control,
+ * tessellation evaluation and geometry shaders as both an input
+ * and an output, it's possible for both old_clip_distance_out_var
+ * and old_clip_distance_in_var to be non-null.
+ */
+ ir_variable *old_clip_distance_out_var;
+ ir_variable *old_clip_distance_in_var;
+
+ /**
+ * Pointer to the newly-created gl_ClipDistanceMESA variable.
+ */
+ ir_variable *new_clip_distance_out_var;
+ ir_variable *new_clip_distance_in_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_ClipDistance as an array of floats with a
+ * declaration of gl_ClipDistanceMESA as an array of vec4's.
+ */
+ir_visitor_status
+lower_clip_distance_visitor::visit(ir_variable *ir)
+{
+ ir_variable **old_var;
+ ir_variable **new_var;
+
+ if (!ir->name || strcmp(ir->name, "gl_ClipDistance") != 0)
+ return visit_continue;
+ assert (ir->type->is_array());
+
+ if (ir->data.mode == ir_var_shader_out) {
+ if (this->old_clip_distance_out_var)
+ return visit_continue;
+ old_var = &old_clip_distance_out_var;
+ new_var = &new_clip_distance_out_var;
+ } else if (ir->data.mode == ir_var_shader_in) {
+ if (this->old_clip_distance_in_var)
+ return visit_continue;
+ old_var = &old_clip_distance_in_var;
+ new_var = &new_clip_distance_in_var;
+ } else {
+ unreachable("not reached");
+ }
+
+ this->progress = true;
+
+ if (!ir->type->fields.array->is_array()) {
+ /* gl_ClipDistance (used for vertex, tessellation evaluation and
+ * geometry output, and fragment input).
+ */
+ assert((ir->data.mode == ir_var_shader_in &&
+ this->shader_stage == MESA_SHADER_FRAGMENT) ||
+ (ir->data.mode == ir_var_shader_out &&
+ (this->shader_stage == MESA_SHADER_VERTEX ||
+ this->shader_stage == MESA_SHADER_TESS_EVAL ||
+ this->shader_stage == MESA_SHADER_GEOMETRY)));
+
+ *old_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 */
+ *new_var = ir->clone(ralloc_parent(ir), NULL);
+
+ /* And change the properties that we need to change */
+ (*new_var)->name = ralloc_strdup(*new_var, "gl_ClipDistanceMESA");
+ (*new_var)->type = glsl_type::get_array_instance(glsl_type::vec4_type,
+ new_size);
+ (*new_var)->data.max_array_access = ir->data.max_array_access / 4;
+
+ ir->replace_with(*new_var);
+ } else {
+ /* 2D gl_ClipDistance (used for tessellation control, tessellation
+ * evaluation and geometry input, and tessellation control output).
+ */
+ assert((ir->data.mode == ir_var_shader_in &&
+ (this->shader_stage == MESA_SHADER_GEOMETRY ||
+ this->shader_stage == MESA_SHADER_TESS_EVAL)) ||
+ this->shader_stage == MESA_SHADER_TESS_CTRL);
+
+ *old_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 */
+ *new_var = ir->clone(ralloc_parent(ir), NULL);
+
+ /* And change the properties that we need to change */
+ (*new_var)->name = ralloc_strdup(*new_var, "gl_ClipDistanceMESA");
+ (*new_var)->type = glsl_type::get_array_instance(
+ glsl_type::get_array_instance(glsl_type::vec4_type,
+ new_size),
+ ir->type->array_size());
+ (*new_var)->data.max_array_access = ir->data.max_array_access / 4;
+
+ ir->replace_with(*new_var);
+ }
+
+ return visit_continue;
+}
+
+
+/**
+ * Create the necessary GLSL rvalues to index into gl_ClipDistanceMESA based
+ * on the rvalue previously used to index into gl_ClipDistance.
+ *
+ * \param array_index Selects one of the vec4's in gl_ClipDistanceMESA
+ * \param swizzle_index Selects a component within the vec4 selected by
+ * array_index.
+ */
+void
+lower_clip_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_ClipDistance 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, "clip_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 clip_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 clip_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_ClipDistance (if gl_ClipDistance is 1D)
+ * - gl_ClipDistance[i] (if gl_ClipDistance is 2D)
+ */
+bool
+lower_clip_distance_visitor::is_clip_distance_vec8(ir_rvalue *ir)
+{
+ /* Note that geometry shaders contain gl_ClipDistance 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_clip_distance_out_var and
+ * this->old_clip_distance_in_var to be non-NULL in the same shader.
+ */
+
+ if (!ir->type->is_array())
+ return false;
+ if (ir->type->fields.array != glsl_type::float_type)
+ return false;
+
+ if (this->old_clip_distance_out_var) {
+ if (ir->variable_referenced() == this->old_clip_distance_out_var)
+ return true;
+ }
+ if (this->old_clip_distance_in_var) {
+ assert(this->shader_stage == MESA_SHADER_TESS_CTRL ||
+ this->shader_stage == MESA_SHADER_TESS_EVAL ||
+ this->shader_stage == MESA_SHADER_GEOMETRY ||
+ this->shader_stage == MESA_SHADER_FRAGMENT);
+
+ if (ir->variable_referenced() == this->old_clip_distance_in_var)
+ return true;
+ }
+ return false;
+}
+
+
+/**
+ * If the given ir satisfies is_clip_distance_vec8(), return new ir
+ * representing its lowered equivalent. That is, map:
+ *
+ * - gl_ClipDistance => gl_ClipDistanceMESA (if gl_ClipDistance is 1D)
+ * - gl_ClipDistance[i] => gl_ClipDistanceMESA[i] (if gl_ClipDistance is 2D)
+ *
+ * Otherwise return NULL.
+ */
+ir_rvalue *
+lower_clip_distance_visitor::lower_clip_distance_vec8(ir_rvalue *ir)
+{
+ if (!ir->type->is_array())
+ return NULL;
+ if (ir->type->fields.array != glsl_type::float_type)
+ return NULL;
+
+ ir_variable **new_var = NULL;
+ if (this->old_clip_distance_out_var) {
+ if (ir->variable_referenced() == this->old_clip_distance_out_var)
+ new_var = &this->new_clip_distance_out_var;
+ }
+ if (this->old_clip_distance_in_var) {
+ if (ir->variable_referenced() == this->old_clip_distance_in_var)
+ new_var = &this->new_clip_distance_in_var;
+ }
+ if (new_var == NULL)
+ return NULL;
+
+ if (ir->as_dereference_variable()) {
+ return new(ralloc_parent(ir)) ir_dereference_variable(*new_var);
+ } else {
+ ir_dereference_array *array_ref = ir->as_dereference_array();
+ assert(array_ref);
+ assert(array_ref->array->as_dereference_variable());
+
+ return new(ralloc_parent(ir))
+ ir_dereference_array(*new_var, array_ref->array_index);
+ }
+}
+
+
+void
+lower_clip_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_ClipDistance
+ * with an expression that indexes into one of the vec4's in
+ * gl_ClipDistanceMESA and accesses the appropriate component.
+ */
+ ir_rvalue *lowered_vec8 =
+ this->lower_clip_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_clip_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_ClipDistanceMESA[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_ClipDistance (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_ClipDistanceMESA as appropriate.
+ *
+ * We need to do a similar replacement for 2D gl_ClipDistance, 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_ClipDistance
+ */
+ir_visitor_status
+lower_clip_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_clip_distance_vec8(ir->lhs) ||
+ this->is_clip_distance_vec8(ir->rhs)) {
+ /* LHS or RHS of the assignment is the entire 1D gl_ClipDistance array
+ * (or a 1D slice of a 2D gl_ClipDistance input array). Since we are
+ * reshaping gl_ClipDistance 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_clip_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_ClipDistance 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_ClipDistance. Each of these
+ * assignments is then lowered to refer to gl_ClipDistanceMESA.
+ *
+ * We need to do a similar replacement for 2D gl_ClipDistance, 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_ClipDistance)
+ */
+ir_visitor_status
+lower_clip_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_clip_distance_vec8(actual_param)) {
+ /* User is trying to pass the whole 1D gl_ClipDistance array (or a 1D
+ * slice of a 2D gl_ClipDistance array) to a function call. Since we
+ * are reshaping gl_ClipDistance 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_clip_distance = new(ctx) ir_variable(
+ actual_param->type, "temp_clip_distance", ir_var_temporary);
+ this->base_ir->insert_before(temp_clip_distance);
+ actual_param->replace_with(
+ new(ctx) ir_dereference_variable(temp_clip_distance));
+ if (formal_param->data.mode == ir_var_function_in
+ || formal_param->data.mode == ir_var_function_inout) {
+ /* Copy from gl_ClipDistance 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_clip_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_ClipDistance 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_clip_distance));
+ this->base_ir->insert_after(new_assignment);
+ this->visit_new_assignment(new_assignment);
+ }
+ }
+ }
+
+ return rvalue_visit(ir);
+}
+
+
+bool
+lower_clip_distance(gl_shader *shader)
+{
+ lower_clip_distance_visitor v(shader->Stage);
+
+ visit_list_elements(&v, shader->ir);
+
+ if (v.new_clip_distance_out_var)
+ shader->symbols->add_variable(v.new_clip_distance_out_var);
+ if (v.new_clip_distance_in_var)
+ shader->symbols->add_variable(v.new_clip_distance_in_var);
+
+ return v.progress;
+}
--
2.8.2
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