/*
* 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_varyings_to_packed.cpp
*
* This lowering pass generates GLSL code that manually packs varyings into
* vec4 slots, for the benefit of back-ends that don't support packed varyings
* natively.
*
* For example, the following shader:
*
* out mat3x2 foo; // location=4, location_frac=0
* out vec3 bar[2]; // location=5, location_frac=2
*
* main()
* {
* ...
* }
*
* Is rewritten to:
*
* mat3x2 foo;
* vec3 bar[2];
* out vec4 packed4; // location=4, location_frac=0
* out vec4 packed5; // location=5, location_frac=0
* out vec4 packed6; // location=6, location_frac=0
*
* main()
* {
* ...
* packed4.xy = foo[0];
* packed4.zw = foo[1];
* packed5.xy = foo[2];
* packed5.zw = bar[0].xy;
* packed6.x = bar[0].z;
* packed6.yzw = bar[1];
* }
*
* This lowering pass properly handles "double parking" of a varying vector
* across two varying slots. For example, in the code above, two of the
* components of bar[0] are stored in packed5, and the remaining component is
* stored in packed6.
*
* Note that in theory, the extra instructions may cause some loss of
* performance. However, hopefully in most cases the performance loss will
* either be absorbed by a later optimization pass, or it will be offset by
* memory bandwidth savings (because fewer varyings are used).
*
* This lowering pass also packs flat floats, ints, and uints together, by
* using ivec4 as the base type of flat "varyings", and using appropriate
* casts to convert floats and uints into ints.
*
* This lowering pass also handles varyings whose type is a struct or an array
* of struct. Structs are packed in order and with no gaps, so there may be a
* performance penalty due to structure elements being double-parked.
*
* Lowering of geometry shader inputs is slightly more complex, since geometry
* inputs are always arrays, so we need to lower arrays to arrays. For
* example, the following input:
*
* in struct Foo {
* float f;
* vec3 v;
* vec2 a[2];
* } arr[3]; // location=4, location_frac=0
*
* Would get lowered like this if it occurred in a fragment shader:
*
* struct Foo {
* float f;
* vec3 v;
* vec2 a[2];
* } arr[3];
* in vec4 packed4; // location=4, location_frac=0
* in vec4 packed5; // location=5, location_frac=0
* in vec4 packed6; // location=6, location_frac=0
* in vec4 packed7; // location=7, location_frac=0
* in vec4 packed8; // location=8, location_frac=0
* in vec4 packed9; // location=9, location_frac=0
*
* main()
* {
* arr[0].f = packed4.x;
* arr[0].v = packed4.yzw;
* arr[0].a[0] = packed5.xy;
* arr[0].a[1] = packed5.zw;
* arr[1].f = packed6.x;
* arr[1].v = packed6.yzw;
* arr[1].a[0] = packed7.xy;
* arr[1].a[1] = packed7.zw;
* arr[2].f = packed8.x;
* arr[2].v = packed8.yzw;
* arr[2].a[0] = packed9.xy;
* arr[2].a[1] = packed9.zw;
* ...
* }
*
* But it would get lowered like this if it occurred in a geometry shader:
*
* struct Foo {
* float f;
* vec3 v;
* vec2 a[2];
* } arr[3];
* in vec4 packed4[3]; // location=4, location_frac=0
* in vec4 packed5[3]; // location=5, location_frac=0
*
* main()
* {
* arr[0].f = packed4[0].x;
* arr[0].v = packed4[0].yzw;
* arr[0].a[0] = packed5[0].xy;
* arr[0].a[1] = packed5[0].zw;
* arr[1].f = packed4[1].x;
* arr[1].v = packed4[1].yzw;
* arr[1].a[0] = packed5[1].xy;
* arr[1].a[1] = packed5[1].zw;
* arr[2].f = packed4[2].x;
* arr[2].v = packed4[2].yzw;
* arr[2].a[0] = packed5[2].xy;
* arr[2].a[1] = packed5[2].zw;
* ...
* }
*/
#include "glsl_symbol_table.h"
#include "ir.h"
#include "ir_builder.h"
#include "ir_optimization.h"
#include "program/prog_instruction.h"
using namespace ir_builder;
namespace {
/**
* Visitor that performs varying packing. For each varying declared in the
* shader, this visitor determines whether it needs to be packed. If so, it
* demotes it to an ordinary global, creates new packed varyings, and
* generates assignments to convert between the original varying and the
* packed varying.
*/
class lower_packed_varyings_visitor
{
public:
lower_packed_varyings_visitor(void *mem_ctx,
unsigned locations_used,
const uint8_t *components,
ir_variable_mode mode,
unsigned gs_input_vertices,
exec_list *out_instructions,
exec_list *out_variables,
bool disable_varying_packing,
bool xfb_enabled);
void run(struct gl_linked_shader *shader);
private:
void bitwise_assign_pack(ir_rvalue *lhs, ir_rvalue *rhs);
void bitwise_assign_unpack(ir_rvalue *lhs, ir_rvalue *rhs);
unsigned lower_rvalue(ir_rvalue *rvalue, unsigned fine_location,
ir_variable *unpacked_var, const char *name,
bool gs_input_toplevel, unsigned vertex_index);
unsigned lower_arraylike(ir_rvalue *rvalue, unsigned array_size,
unsigned fine_location,
ir_variable *unpacked_var, const char *name,
bool gs_input_toplevel, unsigned vertex_index);
ir_dereference *get_packed_varying_deref(unsigned location,
ir_variable *unpacked_var,
const char *name,
unsigned vertex_index);
bool needs_lowering(ir_variable *var);
/**
* Memory context used to allocate new instructions for the shader.
*/
void * const mem_ctx;
/**
* Number of generic varying slots which are used by this shader. This is
* used to allocate temporary intermediate data structures. If any varying
* used by this shader has a location greater than or equal to
* VARYING_SLOT_VAR0 + locations_used, an assertion will fire.
*/
const unsigned locations_used;
const uint8_t* components;
/**
* Array of pointers to the packed varyings that have been created for each
* generic varying slot. NULL entries in this array indicate varying slots
* for which a packed varying has not been created yet.
*/
ir_variable **packed_varyings;
/**
* Type of varying which is being lowered in this pass (either
* ir_var_shader_in or ir_var_shader_out).
*/
const ir_variable_mode mode;
/**
* If we are currently lowering geometry shader inputs, the number of input
* vertices the geometry shader accepts. Otherwise zero.
*/
const unsigned gs_input_vertices;
/**
* Exec list into which the visitor should insert the packing instructions.
* Caller provides this list; it should insert the instructions into the
* appropriate place in the shader once the visitor has finished running.
*/
exec_list *out_instructions;
/**
* Exec list into which the visitor should insert any new variables.
*/
exec_list *out_variables;
bool disable_varying_packing;
bool xfb_enabled;
};
} /* anonymous namespace */
lower_packed_varyings_visitor::lower_packed_varyings_visitor(
void *mem_ctx, unsigned locations_used, const uint8_t *components,
ir_variable_mode mode,
unsigned gs_input_vertices, exec_list *out_instructions,
exec_list *out_variables, bool disable_varying_packing,
bool xfb_enabled)
: mem_ctx(mem_ctx),
locations_used(locations_used),
components(components),
packed_varyings((ir_variable **)
rzalloc_array_size(mem_ctx, sizeof(*packed_varyings),
locations_used)),
mode(mode),
gs_input_vertices(gs_input_vertices),
out_instructions(out_instructions),
out_variables(out_variables),
disable_varying_packing(disable_varying_packing),
xfb_enabled(xfb_enabled)
{
}
void
lower_packed_varyings_visitor::run(struct gl_linked_shader *shader)
{
foreach_in_list(ir_instruction, node, shader->ir) {
ir_variable *var = node->as_variable();
if (var == NULL)
continue;
if (var->data.mode != this->mode ||
var->data.location < VARYING_SLOT_VAR0 ||
!this->needs_lowering(var))
continue;
/* This lowering pass is only capable of packing floats and ints
* together when their interpolation mode is "flat". Treat integers as
* being flat when the interpolation mode is none.
*/
assert(var->data.interpolation == INTERP_MODE_FLAT ||
var->data.interpolation == INTERP_MODE_NONE ||
!var->type->contains_integer());
/* Clone the variable for program resource list before
* it gets modified and lost.
*/
if (!shader->packed_varyings)
shader->packed_varyings = new (shader) exec_list;
shader->packed_varyings->push_tail(var->clone(shader, NULL));
/* Change the old varying into an ordinary global. */
assert(var->data.mode != ir_var_temporary);
var->data.mode = ir_var_auto;
/* Create a reference to the old varying. */
ir_dereference_variable *deref
= new(this->mem_ctx) ir_dereference_variable(var);
/* Recursively pack or unpack it. */
this->lower_rvalue(deref, var->data.location * 4 + var->data.location_frac, var,
var->name, this->gs_input_vertices != 0, 0);
}
}
#define SWIZZLE_ZWZW MAKE_SWIZZLE4(SWIZZLE_Z, SWIZZLE_W, SWIZZLE_Z, SWIZZLE_W)
/**
* Make an ir_assignment from \c rhs to \c lhs, performing appropriate
* bitcasts if necessary to match up types.
*
* This function is called when packing varyings.
*/
void
lower_packed_varyings_visitor::bitwise_assign_pack(ir_rvalue *lhs,
ir_rvalue *rhs)
{
if (lhs->type->base_type != rhs->type->base_type) {
/* Since we only mix types in flat varyings, and we always store flat
* varyings as type ivec4, we need only produce conversions from (uint
* or float) to int.
*/
assert(lhs->type->base_type == GLSL_TYPE_INT);
switch (rhs->type->base_type) {
case GLSL_TYPE_UINT:
rhs = new(this->mem_ctx)
ir_expression(ir_unop_u2i, lhs->type, rhs);
break;
case GLSL_TYPE_FLOAT:
rhs = new(this->mem_ctx)
ir_expression(ir_unop_bitcast_f2i, lhs->type, rhs);
break;
case GLSL_TYPE_DOUBLE:
assert(rhs->type->vector_elements <= 2);
if (rhs->type->vector_elements == 2) {
ir_variable *t = new(mem_ctx) ir_variable(lhs->type, "pack", ir_var_temporary);
assert(lhs->type->vector_elements == 4);
this->out_variables->push_tail(t);
this->out_instructions->push_tail(
assign(t, u2i(expr(ir_unop_unpack_double_2x32, swizzle_x(rhs->clone(mem_ctx, NULL)))), 0x3));
this->out_instructions->push_tail(
assign(t, u2i(expr(ir_unop_unpack_double_2x32, swizzle_y(rhs))), 0xc));
rhs = deref(t).val;
} else {
rhs = u2i(expr(ir_unop_unpack_double_2x32, rhs));
}
break;
case GLSL_TYPE_INT64:
assert(rhs->type->vector_elements <= 2);
if (rhs->type->vector_elements == 2) {
ir_variable *t = new(mem_ctx) ir_variable(lhs->type, "pack", ir_var_temporary);
assert(lhs->type->vector_elements == 4);
this->out_variables->push_tail(t);
this->out_instructions->push_tail(
assign(t, expr(ir_unop_unpack_int_2x32, swizzle_x(rhs->clone(mem_ctx, NULL))), 0x3));
this->out_instructions->push_tail(
assign(t, expr(ir_unop_unpack_int_2x32, swizzle_y(rhs)), 0xc));
rhs = deref(t).val;
} else {
rhs = expr(ir_unop_unpack_int_2x32, rhs);
}
break;
case GLSL_TYPE_UINT64:
assert(rhs->type->vector_elements <= 2);
if (rhs->type->vector_elements == 2) {
ir_variable *t = new(mem_ctx) ir_variable(lhs->type, "pack", ir_var_temporary);
assert(lhs->type->vector_elements == 4);
this->out_variables->push_tail(t);
this->out_instructions->push_tail(
assign(t, u2i(expr(ir_unop_unpack_uint_2x32, swizzle_x(rhs->clone(mem_ctx, NULL)))), 0x3));
this->out_instructions->push_tail(
assign(t, u2i(expr(ir_unop_unpack_uint_2x32, swizzle_y(rhs))), 0xc));
rhs = deref(t).val;
} else {
rhs = u2i(expr(ir_unop_unpack_uint_2x32, rhs));
}
break;
case GLSL_TYPE_SAMPLER:
rhs = u2i(expr(ir_unop_unpack_sampler_2x32, rhs));
break;
case GLSL_TYPE_IMAGE:
rhs = u2i(expr(ir_unop_unpack_image_2x32, rhs));
break;
default:
assert(!"Unexpected type conversion while lowering varyings");
break;
}
}
this->out_instructions->push_tail(new (this->mem_ctx) ir_assignment(lhs, rhs));
}
/**
* Make an ir_assignment from \c rhs to \c lhs, performing appropriate
* bitcasts if necessary to match up types.
*
* This function is called when unpacking varyings.
*/
void
lower_packed_varyings_visitor::bitwise_assign_unpack(ir_rvalue *lhs,
ir_rvalue *rhs)
{
if (lhs->type->base_type != rhs->type->base_type) {
/* Since we only mix types in flat varyings, and we always store flat
* varyings as type ivec4, we need only produce conversions from int to
* (uint or float).
*/
assert(rhs->type->base_type == GLSL_TYPE_INT);
switch (lhs->type->base_type) {
case GLSL_TYPE_UINT:
rhs = new(this->mem_ctx)
ir_expression(ir_unop_i2u, lhs->type, rhs);
break;
case GLSL_TYPE_FLOAT:
rhs = new(this->mem_ctx)
ir_expression(ir_unop_bitcast_i2f, lhs->type, rhs);
break;
case GLSL_TYPE_DOUBLE:
assert(lhs->type->vector_elements <= 2);
if (lhs->type->vector_elements == 2) {
ir_variable *t = new(mem_ctx) ir_variable(lhs->type, "unpack", ir_var_temporary);
assert(rhs->type->vector_elements == 4);
this->out_variables->push_tail(t);
this->out_instructions->push_tail(
assign(t, expr(ir_unop_pack_double_2x32, i2u(swizzle_xy(rhs->clone(mem_ctx, NULL)))), 0x1));
this->out_instructions->push_tail(
assign(t, expr(ir_unop_pack_double_2x32, i2u(swizzle(rhs->clone(mem_ctx, NULL), SWIZZLE_ZWZW, 2))), 0x2));
rhs = deref(t).val;
} else {
rhs = expr(ir_unop_pack_double_2x32, i2u(rhs));
}
break;
case GLSL_TYPE_INT64:
assert(lhs->type->vector_elements <= 2);
if (lhs->type->vector_elements == 2) {
ir_variable *t = new(mem_ctx) ir_variable(lhs->type, "unpack", ir_var_temporary);
assert(rhs->type->vector_elements == 4);
this->out_variables->push_tail(t);
this->out_instructions->push_tail(
assign(t, expr(ir_unop_pack_int_2x32, swizzle_xy(rhs->clone(mem_ctx, NULL))), 0x1));
this->out_instructions->push_tail(
assign(t, expr(ir_unop_pack_int_2x32, swizzle(rhs->clone(mem_ctx, NULL), SWIZZLE_ZWZW, 2)), 0x2));
rhs = deref(t).val;
} else {
rhs = expr(ir_unop_pack_int_2x32, rhs);
}
break;
case GLSL_TYPE_UINT64:
assert(lhs->type->vector_elements <= 2);
if (lhs->type->vector_elements == 2) {
ir_variable *t = new(mem_ctx) ir_variable(lhs->type, "unpack", ir_var_temporary);
assert(rhs->type->vector_elements == 4);
this->out_variables->push_tail(t);
this->out_instructions->push_tail(
assign(t, expr(ir_unop_pack_uint_2x32, i2u(swizzle_xy(rhs->clone(mem_ctx, NULL)))), 0x1));
this->out_instructions->push_tail(
assign(t, expr(ir_unop_pack_uint_2x32, i2u(swizzle(rhs->clone(mem_ctx, NULL), SWIZZLE_ZWZW, 2))), 0x2));
rhs = deref(t).val;
} else {
rhs = expr(ir_unop_pack_uint_2x32, i2u(rhs));
}
break;
case GLSL_TYPE_SAMPLER:
rhs = new(mem_ctx)
ir_expression(ir_unop_pack_sampler_2x32, lhs->type, i2u(rhs));
break;
case GLSL_TYPE_IMAGE:
rhs = new(mem_ctx)
ir_expression(ir_unop_pack_image_2x32, lhs->type, i2u(rhs));
break;
default:
assert(!"Unexpected type conversion while lowering varyings");
break;
}
}
this->out_instructions->push_tail(new(this->mem_ctx) ir_assignment(lhs, rhs));
}
/**
* Recursively pack or unpack the given varying (or portion of a varying) by
* traversing all of its constituent vectors.
*
* \param fine_location is the location where the first constituent vector
* should be packed--the word "fine" indicates that this location is expressed
* in multiples of a float, rather than multiples of a vec4 as is used
* elsewhere in Mesa.
*
* \param gs_input_toplevel should be set to true if we are lowering geometry
* shader inputs, and we are currently lowering the whole input variable
* (i.e. we are lowering the array whose index selects the vertex).
*
* \param vertex_index: if we are lowering geometry shader inputs, and the
* level of the array that we are currently lowering is *not* the top level,
* then this indicates which vertex we are currently lowering. Otherwise it
* is ignored.
*
* \return the location where the next constituent vector (after this one)
* should be packed.
*/
unsigned
lower_packed_varyings_visitor::lower_rvalue(ir_rvalue *rvalue,
unsigned fine_location,
ir_variable *unpacked_var,
const char *name,
bool gs_input_toplevel,
unsigned vertex_index)
{
unsigned dmul = rvalue->type->is_64bit() ? 2 : 1;
/* When gs_input_toplevel is set, we should be looking at a geometry shader
* input array.
*/
assert(!gs_input_toplevel || rvalue->type->is_array());
if (rvalue->type->is_record()) {
for (unsigned i = 0; i < rvalue->type->length; i++) {
if (i != 0)
rvalue = rvalue->clone(this->mem_ctx, NULL);
const char *field_name = rvalue->type->fields.structure[i].name;
ir_dereference_record *dereference_record = new(this->mem_ctx)
ir_dereference_record(rvalue, field_name);
char *deref_name
= ralloc_asprintf(this->mem_ctx, "%s.%s", name, field_name);
fine_location = this->lower_rvalue(dereference_record, fine_location,
unpacked_var, deref_name, false,
vertex_index);
}
return fine_location;
} else if (rvalue->type->is_array()) {
/* Arrays are packed/unpacked by considering each array element in
* sequence.
*/
return this->lower_arraylike(rvalue, rvalue->type->array_size(),
fine_location, unpacked_var, name,
gs_input_toplevel, vertex_index);
} else if (rvalue->type->is_matrix()) {
/* Matrices are packed/unpacked by considering each column vector in
* sequence.
*/
return this->lower_arraylike(rvalue, rvalue->type->matrix_columns,
fine_location, unpacked_var, name,
false, vertex_index);
} else if (rvalue->type->vector_elements * dmul +
fine_location % 4 > 4) {
/* This vector is going to be "double parked" across two varying slots,
* so handle it as two separate assignments. For doubles, a dvec3/dvec4
* can end up being spread over 3 slots. However the second splitting
* will happen later, here we just always want to split into 2.
*/
unsigned left_components, right_components;
unsigned left_swizzle_values[4] = { 0, 0, 0, 0 };
unsigned right_swizzle_values[4] = { 0, 0, 0, 0 };
char left_swizzle_name[4] = { 0, 0, 0, 0 };
char right_swizzle_name[4] = { 0, 0, 0, 0 };
left_components = 4 - fine_location % 4;
if (rvalue->type->is_64bit()) {
/* We might actually end up with 0 left components! */
left_components /= 2;
}
right_components = rvalue->type->vector_elements - left_components;
for (unsigned i = 0; i < left_components; i++) {
left_swizzle_values[i] = i;
left_swizzle_name[i] = "xyzw"[i];
}
for (unsigned i = 0; i < right_components; i++) {
right_swizzle_values[i] = i + left_components;
right_swizzle_name[i] = "xyzw"[i + left_components];
}
ir_swizzle *left_swizzle = new(this->mem_ctx)
ir_swizzle(rvalue, left_swizzle_values, left_components);
ir_swizzle *right_swizzle = new(this->mem_ctx)
ir_swizzle(rvalue->clone(this->mem_ctx, NULL), right_swizzle_values,
right_components);
char *left_name
= ralloc_asprintf(this->mem_ctx, "%s.%s", name, left_swizzle_name);
char *right_name
= ralloc_asprintf(this->mem_ctx, "%s.%s", name, right_swizzle_name);
if (left_components)
fine_location = this->lower_rvalue(left_swizzle, fine_location,
unpacked_var, left_name, false,
vertex_index);
else
/* Top up the fine location to the next slot */
fine_location++;
return this->lower_rvalue(right_swizzle, fine_location, unpacked_var,
right_name, false, vertex_index);
} else {
/* No special handling is necessary; pack the rvalue into the
* varying.
*/
unsigned swizzle_values[4] = { 0, 0, 0, 0 };
unsigned components = rvalue->type->vector_elements * dmul;
unsigned location = fine_location / 4;
unsigned location_frac = fine_location % 4;
for (unsigned i = 0; i < components; ++i)
swizzle_values[i] = i + location_frac;
ir_dereference *packed_deref =
this->get_packed_varying_deref(location, unpacked_var, name,
vertex_index);
if (unpacked_var->data.stream != 0) {
assert(unpacked_var->data.stream < 4);
ir_variable *packed_var = packed_deref->variable_referenced();
for (unsigned i = 0; i < components; ++i) {
packed_var->data.stream |=
unpacked_var->data.stream << (2 * (location_frac + i));
}
}
ir_swizzle *swizzle = new(this->mem_ctx)
ir_swizzle(packed_deref, swizzle_values, components);
if (this->mode == ir_var_shader_out) {
this->bitwise_assign_pack(swizzle, rvalue);
} else {
this->bitwise_assign_unpack(rvalue, swizzle);
}
return fine_location + components;
}
}
/**
* Recursively pack or unpack a varying for which we need to iterate over its
* constituent elements, accessing each one using an ir_dereference_array.
* This takes care of both arrays and matrices, since ir_dereference_array
* treats a matrix like an array of its column vectors.
*
* \param gs_input_toplevel should be set to true if we are lowering geometry
* shader inputs, and we are currently lowering the whole input variable
* (i.e. we are lowering the array whose index selects the vertex).
*
* \param vertex_index: if we are lowering geometry shader inputs, and the
* level of the array that we are currently lowering is *not* the top level,
* then this indicates which vertex we are currently lowering. Otherwise it
* is ignored.
*/
unsigned
lower_packed_varyings_visitor::lower_arraylike(ir_rvalue *rvalue,
unsigned array_size,
unsigned fine_location,
ir_variable *unpacked_var,
const char *name,
bool gs_input_toplevel,
unsigned vertex_index)
{
for (unsigned i = 0; i < array_size; i++) {
if (i != 0)
rvalue = rvalue->clone(this->mem_ctx, NULL);
ir_constant *constant = new(this->mem_ctx) ir_constant(i);
ir_dereference_array *dereference_array = new(this->mem_ctx)
ir_dereference_array(rvalue, constant);
if (gs_input_toplevel) {
/* Geometry shader inputs are a special case. Instead of storing
* each element of the array at a different location, all elements
* are at the same location, but with a different vertex index.
*/
(void) this->lower_rvalue(dereference_array, fine_location,
unpacked_var, name, false, i);
} else {
char *subscripted_name
= ralloc_asprintf(this->mem_ctx, "%s[%d]", name, i);
fine_location =
this->lower_rvalue(dereference_array, fine_location,
unpacked_var, subscripted_name,
false, vertex_index);
}
}
return fine_location;
}
/**
* Retrieve the packed varying corresponding to the given varying location.
* If no packed varying has been created for the given varying location yet,
* create it and add it to the shader before returning it.
*
* The newly created varying inherits its interpolation parameters from \c
* unpacked_var. Its base type is ivec4 if we are lowering a flat varying,
* vec4 otherwise.
*
* \param vertex_index: if we are lowering geometry shader inputs, then this
* indicates which vertex we are currently lowering. Otherwise it is ignored.
*/
ir_dereference *
lower_packed_varyings_visitor::get_packed_varying_deref(
unsigned location, ir_variable *unpacked_var, const char *name,
unsigned vertex_index)
{
unsigned slot = location - VARYING_SLOT_VAR0;
assert(slot < locations_used);
if (this->packed_varyings[slot] == NULL) {
char *packed_name = ralloc_asprintf(this->mem_ctx, "packed:%s", name);
const glsl_type *packed_type;
assert(components[slot] != 0);
if (unpacked_var->is_interpolation_flat())
packed_type = glsl_type::get_instance(GLSL_TYPE_INT, components[slot], 1);
else
packed_type = glsl_type::get_instance(GLSL_TYPE_FLOAT, components[slot], 1);
if (this->gs_input_vertices != 0) {
packed_type =
glsl_type::get_array_instance(packed_type,
this->gs_input_vertices);
}
ir_variable *packed_var = new(this->mem_ctx)
ir_variable(packed_type, packed_name, this->mode);
if (this->gs_input_vertices != 0) {
/* Prevent update_array_sizes() from messing with the size of the
* array.
*/
packed_var->data.max_array_access = this->gs_input_vertices - 1;
}
packed_var->data.centroid = unpacked_var->data.centroid;
packed_var->data.sample = unpacked_var->data.sample;
packed_var->data.patch = unpacked_var->data.patch;
packed_var->data.interpolation =
packed_type->without_array() == glsl_type::ivec4_type
? unsigned(INTERP_MODE_FLAT) : unpacked_var->data.interpolation;
packed_var->data.location = location;
packed_var->data.precision = unpacked_var->data.precision;
packed_var->data.always_active_io = unpacked_var->data.always_active_io;
packed_var->data.stream = 1u << 31;
unpacked_var->insert_before(packed_var);
this->packed_varyings[slot] = packed_var;
} else {
/* For geometry shader inputs, only update the packed variable name the
* first time we visit each component.
*/
if (this->gs_input_vertices == 0 || vertex_index == 0) {
ir_variable *var = this->packed_varyings[slot];
if (var->is_name_ralloced())
ralloc_asprintf_append((char **) &var->name, ",%s", name);
else
var->name = ralloc_asprintf(var, "%s,%s", var->name, name);
}
}
ir_dereference *deref = new(this->mem_ctx)
ir_dereference_variable(this->packed_varyings[slot]);
if (this->gs_input_vertices != 0) {
/* When lowering GS inputs, the packed variable is an array, so we need
* to dereference it using vertex_index.
*/
ir_constant *constant = new(this->mem_ctx) ir_constant(vertex_index);
deref = new(this->mem_ctx) ir_dereference_array(deref, constant);
}
return deref;
}
bool
lower_packed_varyings_visitor::needs_lowering(ir_variable *var)
{
/* Things composed of vec4's, varyings with explicitly assigned
* locations or varyings marked as must_be_shader_input (which might be used
* by interpolateAt* functions) shouldn't be lowered. Everything else can be.
*/
if (var->data.explicit_location || var->data.must_be_shader_input)
return false;
/* Override disable_varying_packing if the var is only used by transform
* feedback. Also override it if transform feedback is enabled and the
* variable is an array, struct or matrix as the elements of these types
* will always have the same interpolation and therefore are safe to pack.
*/
const glsl_type *type = var->type;
if (disable_varying_packing && !var->data.is_xfb_only &&
!((type->is_array() || type->is_record() || type->is_matrix()) &&
xfb_enabled))
return false;
type = type->without_array();
if (type->vector_elements == 4 && !type->is_64bit())
return false;
return true;
}
/**
* Visitor that splices varying packing code before every use of EmitVertex()
* in a geometry shader.
*/
class lower_packed_varyings_gs_splicer : public ir_hierarchical_visitor
{
public:
explicit lower_packed_varyings_gs_splicer(void *mem_ctx,
const exec_list *instructions);
virtual ir_visitor_status visit_leave(ir_emit_vertex *ev);
private:
/**
* Memory context used to allocate new instructions for the shader.
*/
void * const mem_ctx;
/**
* Instructions that should be spliced into place before each EmitVertex()
* call.
*/
const exec_list *instructions;
};
lower_packed_varyings_gs_splicer::lower_packed_varyings_gs_splicer(
void *mem_ctx, const exec_list *instructions)
: mem_ctx(mem_ctx), instructions(instructions)
{
}
ir_visitor_status
lower_packed_varyings_gs_splicer::visit_leave(ir_emit_vertex *ev)
{
foreach_in_list(ir_instruction, ir, this->instructions) {
ev->insert_before(ir->clone(this->mem_ctx, NULL));
}
return visit_continue;
}
/**
* Visitor that splices varying packing code before every return.
*/
class lower_packed_varyings_return_splicer : public ir_hierarchical_visitor
{
public:
explicit lower_packed_varyings_return_splicer(void *mem_ctx,
const exec_list *instructions);
virtual ir_visitor_status visit_leave(ir_return *ret);
private:
/**
* Memory context used to allocate new instructions for the shader.
*/
void * const mem_ctx;
/**
* Instructions that should be spliced into place before each return.
*/
const exec_list *instructions;
};
lower_packed_varyings_return_splicer::lower_packed_varyings_return_splicer(
void *mem_ctx, const exec_list *instructions)
: mem_ctx(mem_ctx), instructions(instructions)
{
}
ir_visitor_status
lower_packed_varyings_return_splicer::visit_leave(ir_return *ret)
{
foreach_in_list(ir_instruction, ir, this->instructions) {
ret->insert_before(ir->clone(this->mem_ctx, NULL));
}
return visit_continue;
}
void
lower_packed_varyings(void *mem_ctx, unsigned locations_used,
const uint8_t *components,
ir_variable_mode mode, unsigned gs_input_vertices,
gl_linked_shader *shader, bool disable_varying_packing,
bool xfb_enabled)
{
exec_list *instructions = shader->ir;
ir_function *main_func = shader->symbols->get_function("main");
exec_list void_parameters;
ir_function_signature *main_func_sig
= main_func->matching_signature(NULL, &void_parameters, false);
exec_list new_instructions, new_variables;
lower_packed_varyings_visitor visitor(mem_ctx,
locations_used,
components,
mode,
gs_input_vertices,
&new_instructions,
&new_variables,
disable_varying_packing,
xfb_enabled);
visitor.run(shader);
if (mode == ir_var_shader_out) {
if (shader->Stage == MESA_SHADER_GEOMETRY) {
/* For geometry shaders, outputs need to be lowered before each call
* to EmitVertex()
*/
lower_packed_varyings_gs_splicer splicer(mem_ctx, &new_instructions);
/* Add all the variables in first. */
main_func_sig->body.get_head_raw()->insert_before(&new_variables);
/* Now update all the EmitVertex instances */
splicer.run(instructions);
} else {
/* For other shader types, outputs need to be lowered before each
* return statement and at the end of main()
*/
lower_packed_varyings_return_splicer splicer(mem_ctx, &new_instructions);
main_func_sig->body.get_head_raw()->insert_before(&new_variables);
splicer.run(instructions);
/* Lower outputs at the end of main() if the last instruction is not
* a return statement
*/
if (((ir_instruction*)instructions->get_tail())->ir_type != ir_type_return) {
main_func_sig->body.append_list(&new_instructions);
}
}
} else {
/* Shader inputs need to be lowered at the beginning of main() */
main_func_sig->body.get_head_raw()->insert_before(&new_instructions);
main_func_sig->body.get_head_raw()->insert_before(&new_variables);
}
}