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diff --git a/src/compiler/glsl/lower_packed_varyings.cpp b/src/compiler/glsl/lower_packed_varyings.cpp
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+/*
+ * 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,
+ ir_variable_mode mode,
+ unsigned gs_input_vertices,
+ exec_list *out_instructions,
+ exec_list *out_variables);
+
+ void run(struct gl_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;
+
+ /**
+ * 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;
+};
+
+} /* anonymous namespace */
+
+lower_packed_varyings_visitor::lower_packed_varyings_visitor(
+ void *mem_ctx, unsigned locations_used, ir_variable_mode mode,
+ unsigned gs_input_vertices, exec_list *out_instructions,
+ exec_list *out_variables)
+ : mem_ctx(mem_ctx),
+ locations_used(locations_used),
+ 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)
+{
+}
+
+void
+lower_packed_varyings_visitor::run(struct gl_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". Therefore, to be
+ * safe, caller should ensure that integral varyings always use flat
+ * interpolation, even when this is not required by GLSL.
+ */
+ assert(var->data.interpolation == INTERP_QUALIFIER_FLAT ||
+ !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;
+ 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;
+ 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_double() ? 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_double()) {
+ /* 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);
+ 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;
+ if (unpacked_var->data.interpolation == INTERP_QUALIFIER_FLAT)
+ packed_type = glsl_type::ivec4_type;
+ else
+ packed_type = glsl_type::vec4_type;
+ 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 = 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;
+ 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) {
+ ralloc_asprintf_append((char **) &this->packed_varyings[slot]->name,
+ ",%s", 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 and varyings with explicitly assigned
+ * locations don't need lowering. Everything else does.
+ */
+ if (var->data.explicit_location)
+ return false;
+
+ const glsl_type *type = var->type->without_array();
+ if (type->vector_elements == 4 && !type->is_double())
+ 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;
+}
+
+
+void
+lower_packed_varyings(void *mem_ctx, unsigned locations_used,
+ ir_variable_mode mode, unsigned gs_input_vertices,
+ gl_shader *shader)
+{
+ 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, mode,
+ gs_input_vertices,
+ &new_instructions,
+ &new_variables);
+ 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.head->insert_before(&new_variables);
+
+ /* Now update all the EmitVertex instances */
+ splicer.run(instructions);
+ } else {
+ /* For other shader types, outputs need to be lowered at the end of
+ * main()
+ */
+ main_func_sig->body.append_list(&new_variables);
+ main_func_sig->body.append_list(&new_instructions);
+ }
+ } else {
+ /* Shader inputs need to be lowered at the beginning of main() */
+ main_func_sig->body.head->insert_before(&new_instructions);
+ main_func_sig->body.head->insert_before(&new_variables);
+ }
+}