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Diffstat (limited to 'src/compiler/glsl/lower_packed_varyings.cpp')
-rw-r--r-- | src/compiler/glsl/lower_packed_varyings.cpp | 749 |
1 files changed, 749 insertions, 0 deletions
diff --git a/src/compiler/glsl/lower_packed_varyings.cpp b/src/compiler/glsl/lower_packed_varyings.cpp new file mode 100644 index 00000000000..8d1eb1725d5 --- /dev/null +++ b/src/compiler/glsl/lower_packed_varyings.cpp @@ -0,0 +1,749 @@ +/* + * 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); + } +} |