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Diffstat (limited to 'src/glsl/lower_buffer_access.cpp')
| -rw-r--r-- | src/glsl/lower_buffer_access.cpp | 216 |
1 files changed, 216 insertions, 0 deletions
diff --git a/src/glsl/lower_buffer_access.cpp b/src/glsl/lower_buffer_access.cpp new file mode 100644 index 00000000000..7428742adfc --- /dev/null +++ b/src/glsl/lower_buffer_access.cpp @@ -0,0 +1,216 @@ +/* + * Copyright (c) 2015 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_buffer_access.cpp + * + * Helper for IR lowering pass to replace dereferences of buffer object based + * shader variables with intrinsic function calls. + * + * This helper is used by lowering passes for UBOs, SSBOs and compute shader + * shared variables. + */ + +#include "lower_buffer_access.h" +#include "ir_builder.h" +#include "main/macros.h" +#include "util/list.h" +#include "glsl_parser_extras.h" + +using namespace ir_builder; + +namespace lower_buffer_access { + +static inline int +writemask_for_size(unsigned n) +{ + return ((1 << n) - 1); +} + +/** + * Takes a deref and recursively calls itself to break the deref down to the + * point that the reads or writes generated are contiguous scalars or vectors. + */ +void +lower_buffer_access::emit_access(void *mem_ctx, + bool is_write, + ir_dereference *deref, + ir_variable *base_offset, + unsigned int deref_offset, + bool row_major, + int matrix_columns, + unsigned int packing, + unsigned int write_mask) +{ + if (deref->type->is_record()) { + unsigned int field_offset = 0; + + for (unsigned i = 0; i < deref->type->length; i++) { + const struct glsl_struct_field *field = + &deref->type->fields.structure[i]; + ir_dereference *field_deref = + new(mem_ctx) ir_dereference_record(deref->clone(mem_ctx, NULL), + field->name); + + field_offset = + glsl_align(field_offset, + field->type->std140_base_alignment(row_major)); + + emit_access(mem_ctx, is_write, field_deref, base_offset, + deref_offset + field_offset, + row_major, 1, packing, + writemask_for_size(field_deref->type->vector_elements)); + + field_offset += field->type->std140_size(row_major); + } + return; + } + + if (deref->type->is_array()) { + unsigned array_stride = packing == GLSL_INTERFACE_PACKING_STD430 ? + deref->type->fields.array->std430_array_stride(row_major) : + glsl_align(deref->type->fields.array->std140_size(row_major), 16); + + for (unsigned i = 0; i < deref->type->length; i++) { + ir_constant *element = new(mem_ctx) ir_constant(i); + ir_dereference *element_deref = + new(mem_ctx) ir_dereference_array(deref->clone(mem_ctx, NULL), + element); + emit_access(mem_ctx, is_write, element_deref, base_offset, + deref_offset + i * array_stride, + row_major, 1, packing, + writemask_for_size(element_deref->type->vector_elements)); + } + return; + } + + if (deref->type->is_matrix()) { + for (unsigned i = 0; i < deref->type->matrix_columns; i++) { + ir_constant *col = new(mem_ctx) ir_constant(i); + ir_dereference *col_deref = + new(mem_ctx) ir_dereference_array(deref->clone(mem_ctx, NULL), col); + + if (row_major) { + /* For a row-major matrix, the next column starts at the next + * element. + */ + int size_mul = deref->type->is_double() ? 8 : 4; + emit_access(mem_ctx, is_write, col_deref, base_offset, + deref_offset + i * size_mul, + row_major, deref->type->matrix_columns, packing, + writemask_for_size(col_deref->type->vector_elements)); + } else { + int size_mul; + + /* std430 doesn't round up vec2 size to a vec4 size */ + if (packing == GLSL_INTERFACE_PACKING_STD430 && + deref->type->vector_elements == 2 && + !deref->type->is_double()) { + size_mul = 8; + } else { + /* std140 always rounds the stride of arrays (and matrices) to a + * vec4, so matrices are always 16 between columns/rows. With + * doubles, they will be 32 apart when there are more than 2 rows. + * + * For both std140 and std430, if the member is a + * three-'component vector with components consuming N basic + * machine units, the base alignment is 4N. For vec4, base + * alignment is 4N. + */ + size_mul = (deref->type->is_double() && + deref->type->vector_elements > 2) ? 32 : 16; + } + + emit_access(mem_ctx, is_write, col_deref, base_offset, + deref_offset + i * size_mul, + row_major, deref->type->matrix_columns, packing, + writemask_for_size(col_deref->type->vector_elements)); + } + } + return; + } + + assert(deref->type->is_scalar() || deref->type->is_vector()); + + if (!row_major) { + ir_rvalue *offset = + add(base_offset, new(mem_ctx) ir_constant(deref_offset)); + unsigned mask = + is_write ? write_mask : (1 << deref->type->vector_elements) - 1; + insert_buffer_access(mem_ctx, deref, deref->type, offset, mask, -1); + } else { + unsigned N = deref->type->is_double() ? 8 : 4; + + /* We're dereffing a column out of a row-major matrix, so we + * gather the vector from each stored row. + */ + assert(deref->type->base_type == GLSL_TYPE_FLOAT || + deref->type->base_type == GLSL_TYPE_DOUBLE); + /* Matrices, row_major or not, are stored as if they were + * arrays of vectors of the appropriate size in std140. + * Arrays have their strides rounded up to a vec4, so the + * matrix stride is always 16. However a double matrix may either be 16 + * or 32 depending on the number of columns. + */ + assert(matrix_columns <= 4); + unsigned matrix_stride = 0; + /* Matrix stride for std430 mat2xY matrices are not rounded up to + * vec4 size. From OpenGL 4.3 spec, section 7.6.2.2 "Standard Uniform + * Block Layout": + * + * "2. If the member is a two- or four-component vector with components + * consuming N basic machine units, the base alignment is 2N or 4N, + * respectively." [...] + * "4. If the member is an array of scalars or vectors, the base alignment + * and array stride are set to match the base alignment of a single array + * element, according to rules (1), (2), and (3), and rounded up to the + * base alignment of a vec4." [...] + * "7. If the member is a row-major matrix with C columns and R rows, the + * matrix is stored identically to an array of R row vectors with C + * components each, according to rule (4)." [...] + * "When using the std430 storage layout, shader storage blocks will be + * laid out in buffer storage identically to uniform and shader storage + * blocks using the std140 layout, except that the base alignment and + * stride of arrays of scalars and vectors in rule 4 and of structures in + * rule 9 are not rounded up a multiple of the base alignment of a vec4." + */ + if (packing == GLSL_INTERFACE_PACKING_STD430 && matrix_columns == 2) + matrix_stride = 2 * N; + else + matrix_stride = glsl_align(matrix_columns * N, 16); + + const glsl_type *deref_type = deref->type->base_type == GLSL_TYPE_FLOAT ? + glsl_type::float_type : glsl_type::double_type; + + for (unsigned i = 0; i < deref->type->vector_elements; i++) { + ir_rvalue *chan_offset = + add(base_offset, + new(mem_ctx) ir_constant(deref_offset + i * matrix_stride)); + if (!is_write || ((1U << i) & write_mask)) + insert_buffer_access(mem_ctx, deref, deref_type, chan_offset, + (1U << i), i); + } + } +} + +} /* namespace lower_buffer_access */ |