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Diffstat (limited to 'src/compiler/glsl/lower_buffer_access.cpp')
| -rw-r--r-- | src/compiler/glsl/lower_buffer_access.cpp | 490 |
1 files changed, 490 insertions, 0 deletions
diff --git a/src/compiler/glsl/lower_buffer_access.cpp b/src/compiler/glsl/lower_buffer_access.cpp new file mode 100644 index 00000000000..f8c8d140ea8 --- /dev/null +++ b/src/compiler/glsl/lower_buffer_access.cpp @@ -0,0 +1,490 @@ +/* + * 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); + } + } +} + +/** + * Determine if a thing being dereferenced is row-major + * + * There is some trickery here. + * + * If the thing being dereferenced is a member of uniform block \b without an + * instance name, then the name of the \c ir_variable is the field name of an + * interface type. If this field is row-major, then the thing referenced is + * row-major. + * + * If the thing being dereferenced is a member of uniform block \b with an + * instance name, then the last dereference in the tree will be an + * \c ir_dereference_record. If that record field is row-major, then the + * thing referenced is row-major. + */ +bool +lower_buffer_access::is_dereferenced_thing_row_major(const ir_rvalue *deref) +{ + bool matrix = false; + const ir_rvalue *ir = deref; + + while (true) { + matrix = matrix || ir->type->without_array()->is_matrix(); + + switch (ir->ir_type) { + case ir_type_dereference_array: { + const ir_dereference_array *const array_deref = + (const ir_dereference_array *) ir; + + ir = array_deref->array; + break; + } + + case ir_type_dereference_record: { + const ir_dereference_record *const record_deref = + (const ir_dereference_record *) ir; + + ir = record_deref->record; + + const int idx = ir->type->field_index(record_deref->field); + assert(idx >= 0); + + const enum glsl_matrix_layout matrix_layout = + glsl_matrix_layout(ir->type->fields.structure[idx].matrix_layout); + + switch (matrix_layout) { + case GLSL_MATRIX_LAYOUT_INHERITED: + break; + case GLSL_MATRIX_LAYOUT_COLUMN_MAJOR: + return false; + case GLSL_MATRIX_LAYOUT_ROW_MAJOR: + return matrix || deref->type->without_array()->is_record(); + } + + break; + } + + case ir_type_dereference_variable: { + const ir_dereference_variable *const var_deref = + (const ir_dereference_variable *) ir; + + const enum glsl_matrix_layout matrix_layout = + glsl_matrix_layout(var_deref->var->data.matrix_layout); + + switch (matrix_layout) { + case GLSL_MATRIX_LAYOUT_INHERITED: { + /* For interface block matrix variables we handle inherited + * layouts at HIR generation time, but we don't do that for shared + * variables, which are always column-major + */ + ir_variable *var = deref->variable_referenced(); + assert((var->is_in_buffer_block() && !matrix) || + var->data.mode == ir_var_shader_shared); + return false; + } + case GLSL_MATRIX_LAYOUT_COLUMN_MAJOR: + return false; + case GLSL_MATRIX_LAYOUT_ROW_MAJOR: + return matrix || deref->type->without_array()->is_record(); + } + + unreachable("invalid matrix layout"); + break; + } + + default: + return false; + } + } + + /* The tree must have ended with a dereference that wasn't an + * ir_dereference_variable. That is invalid, and it should be impossible. + */ + unreachable("invalid dereference tree"); + return false; +} + +/** + * This function initializes various values that will be used later by + * emit_access when actually emitting loads or stores. + * + * Note: const_offset is an input as well as an output, clients must + * initialize it to the offset of the variable in the underlying block, and + * this function will adjust it by adding the constant offset of the member + * being accessed into that variable. + */ +void +lower_buffer_access::setup_buffer_access(void *mem_ctx, + ir_variable *var, + ir_rvalue *deref, + ir_rvalue **offset, + unsigned *const_offset, + bool *row_major, + int *matrix_columns, + unsigned packing) +{ + *offset = new(mem_ctx) ir_constant(0u); + *row_major = is_dereferenced_thing_row_major(deref); + *matrix_columns = 1; + + /* Calculate the offset to the start of the region of the UBO + * dereferenced by *rvalue. This may be a variable offset if an + * array dereference has a variable index. + */ + while (deref) { + switch (deref->ir_type) { + case ir_type_dereference_variable: { + deref = NULL; + break; + } + + case ir_type_dereference_array: { + ir_dereference_array *deref_array = (ir_dereference_array *) deref; + unsigned array_stride; + if (deref_array->array->type->is_vector()) { + /* We get this when storing or loading a component out of a vector + * with a non-constant index. This happens for v[i] = f where v is + * a vector (or m[i][j] = f where m is a matrix). If we don't + * lower that here, it gets turned into v = vector_insert(v, i, + * f), which loads the entire vector, modifies one component and + * then write the entire thing back. That breaks if another + * thread or SIMD channel is modifying the same vector. + */ + array_stride = 4; + if (deref_array->array->type->is_double()) + array_stride *= 2; + } else if (deref_array->array->type->is_matrix() && *row_major) { + /* When loading a vector out of a row major matrix, the + * step between the columns (vectors) is the size of a + * float, while the step between the rows (elements of a + * vector) is handled below in emit_ubo_loads. + */ + array_stride = 4; + if (deref_array->array->type->is_double()) + array_stride *= 2; + *matrix_columns = deref_array->array->type->matrix_columns; + } else if (deref_array->type->without_array()->is_interface()) { + /* We're processing an array dereference of an interface instance + * array. The thing being dereferenced *must* be a variable + * dereference because interfaces cannot be embedded in other + * types. In terms of calculating the offsets for the lowering + * pass, we don't care about the array index. All elements of an + * interface instance array will have the same offsets relative to + * the base of the block that backs them. + */ + deref = deref_array->array->as_dereference(); + break; + } else { + /* Whether or not the field is row-major (because it might be a + * bvec2 or something) does not affect the array itself. We need + * to know whether an array element in its entirety is row-major. + */ + const bool array_row_major = + is_dereferenced_thing_row_major(deref_array); + + /* The array type will give the correct interface packing + * information + */ + if (packing == GLSL_INTERFACE_PACKING_STD430) { + array_stride = deref_array->type->std430_array_stride(array_row_major); + } else { + array_stride = deref_array->type->std140_size(array_row_major); + array_stride = glsl_align(array_stride, 16); + } + } + + ir_rvalue *array_index = deref_array->array_index; + if (array_index->type->base_type == GLSL_TYPE_INT) + array_index = i2u(array_index); + + ir_constant *const_index = + array_index->constant_expression_value(NULL); + if (const_index) { + *const_offset += array_stride * const_index->value.u[0]; + } else { + *offset = add(*offset, + mul(array_index, + new(mem_ctx) ir_constant(array_stride))); + } + deref = deref_array->array->as_dereference(); + break; + } + + case ir_type_dereference_record: { + ir_dereference_record *deref_record = (ir_dereference_record *) deref; + const glsl_type *struct_type = deref_record->record->type; + unsigned intra_struct_offset = 0; + + for (unsigned int i = 0; i < struct_type->length; i++) { + const glsl_type *type = struct_type->fields.structure[i].type; + + ir_dereference_record *field_deref = new(mem_ctx) + ir_dereference_record(deref_record->record, + struct_type->fields.structure[i].name); + const bool field_row_major = + is_dereferenced_thing_row_major(field_deref); + + ralloc_free(field_deref); + + unsigned field_align = 0; + + if (packing == GLSL_INTERFACE_PACKING_STD430) + field_align = type->std430_base_alignment(field_row_major); + else + field_align = type->std140_base_alignment(field_row_major); + + intra_struct_offset = glsl_align(intra_struct_offset, field_align); + + if (strcmp(struct_type->fields.structure[i].name, + deref_record->field) == 0) + break; + + if (packing == GLSL_INTERFACE_PACKING_STD430) + intra_struct_offset += type->std430_size(field_row_major); + else + intra_struct_offset += type->std140_size(field_row_major); + + /* If the field just examined was itself a structure, apply rule + * #9: + * + * "The structure may have padding at the end; the base offset + * of the member following the sub-structure is rounded up to + * the next multiple of the base alignment of the structure." + */ + if (type->without_array()->is_record()) { + intra_struct_offset = glsl_align(intra_struct_offset, + field_align); + + } + } + + *const_offset += intra_struct_offset; + deref = deref_record->record->as_dereference(); + break; + } + + case ir_type_swizzle: { + ir_swizzle *deref_swizzle = (ir_swizzle *) deref; + + assert(deref_swizzle->mask.num_components == 1); + + *const_offset += deref_swizzle->mask.x * sizeof(int); + deref = deref_swizzle->val->as_dereference(); + break; + } + + default: + assert(!"not reached"); + deref = NULL; + break; + } + } +} + +} /* namespace lower_buffer_access */ |