Mesa (master): glsl: encode/decode types using a union with bitfields for readability
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Fri Nov 1 23:37:28 UTC 2019
Module: Mesa
Branch: master
Commit: 21d2fbb8c3e0bfaec1b6896e117df4ae3161d677
URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=21d2fbb8c3e0bfaec1b6896e117df4ae3161d677
Author: Marek Olšák <marek.olsak at amd.com>
Date: Wed Oct 30 20:15:36 2019 -0400
glsl: encode/decode types using a union with bitfields for readability
Reviewed-by: Timothy Arceri <tarceri at itsqueeze.com>
---
src/compiler/glsl_types.cpp | 91 +++++++++++++++++++++++++++------------------
1 file changed, 55 insertions(+), 36 deletions(-)
diff --git a/src/compiler/glsl_types.cpp b/src/compiler/glsl_types.cpp
index e412f16bcfa..017b84a9bda 100644
--- a/src/compiler/glsl_types.cpp
+++ b/src/compiler/glsl_types.cpp
@@ -2573,16 +2573,38 @@ get_struct_type_field_and_pointer_sizes(size_t *s_field_size,
sizeof(((glsl_struct_field *)0)->name);
}
+union packed_type {
+ uint32_t u32;
+ struct {
+ unsigned base_type:5;
+ unsigned interface_row_major:1;
+ unsigned vector_elements:6;
+ unsigned matrix_columns:4;
+ unsigned _pad:16;
+ } basic;
+ struct {
+ unsigned base_type:5;
+ unsigned dimensionality:4;
+ unsigned shadow:1;
+ unsigned array:1;
+ unsigned sampled_type:2;
+ unsigned _pad:19;
+ } sampler;
+};
+
void
encode_type_to_blob(struct blob *blob, const glsl_type *type)
{
- uint32_t encoding;
-
if (!type) {
blob_write_uint32(blob, 0);
return;
}
+ STATIC_ASSERT(sizeof(union packed_type) == 4);
+ union packed_type encoded;
+ encoded.u32 = 0;
+ encoded.basic.base_type = type->base_type;
+
switch (type->base_type) {
case GLSL_TYPE_UINT:
case GLSL_TYPE_INT:
@@ -2596,43 +2618,38 @@ encode_type_to_blob(struct blob *blob, const glsl_type *type)
case GLSL_TYPE_UINT64:
case GLSL_TYPE_INT64:
case GLSL_TYPE_BOOL:
- encoding = (type->base_type << 24) |
- (type->interface_row_major << 10) |
- (type->vector_elements << 4) |
- (type->matrix_columns);
- blob_write_uint32(blob, encoding);
+ encoded.basic.interface_row_major = type->interface_row_major;
+ encoded.basic.vector_elements = type->vector_elements;
+ encoded.basic.matrix_columns = type->matrix_columns;
+ blob_write_uint32(blob, encoded.u32);
blob_write_uint32(blob, type->explicit_stride);
return;
case GLSL_TYPE_SAMPLER:
- encoding = (type->base_type) << 24 |
- (type->sampler_dimensionality << 4) |
- (type->sampler_shadow << 3) |
- (type->sampler_array << 2) |
- (type->sampled_type);
+ encoded.sampler.dimensionality = type->sampler_dimensionality;
+ encoded.sampler.shadow = type->sampler_shadow;
+ encoded.sampler.array = type->sampler_array;
+ encoded.sampler.sampled_type = type->sampled_type;
break;
case GLSL_TYPE_SUBROUTINE:
- encoding = type->base_type << 24;
- blob_write_uint32(blob, encoding);
+ blob_write_uint32(blob, encoded.u32);
blob_write_string(blob, type->name);
return;
case GLSL_TYPE_IMAGE:
- encoding = (type->base_type) << 24 |
- (type->sampler_dimensionality << 3) |
- (type->sampler_array << 2) |
- (type->sampled_type);
+ encoded.sampler.dimensionality = type->sampler_dimensionality;
+ encoded.sampler.array = type->sampler_array;
+ encoded.sampler.sampled_type = type->sampled_type;
break;
case GLSL_TYPE_ATOMIC_UINT:
- encoding = (type->base_type << 24);
break;
case GLSL_TYPE_ARRAY:
- blob_write_uint32(blob, (type->base_type) << 24);
+ blob_write_uint32(blob, encoded.u32);
blob_write_uint32(blob, type->length);
blob_write_uint32(blob, type->explicit_stride);
encode_type_to_blob(blob, type->fields.array);
return;
case GLSL_TYPE_STRUCT:
case GLSL_TYPE_INTERFACE:
- blob_write_uint32(blob, (type->base_type) << 24);
+ blob_write_uint32(blob, encoded.u32);
blob_write_string(blob, type->name);
blob_write_uint32(blob, type->length);
@@ -2657,28 +2674,28 @@ encode_type_to_blob(struct blob *blob, const glsl_type *type)
}
return;
case GLSL_TYPE_VOID:
- encoding = (type->base_type << 24);
break;
case GLSL_TYPE_ERROR:
default:
assert(!"Cannot encode type!");
- encoding = 0;
+ encoded.u32 = 0;
break;
}
- blob_write_uint32(blob, encoding);
+ blob_write_uint32(blob, encoded.u32);
}
const glsl_type *
decode_type_from_blob(struct blob_reader *blob)
{
- uint32_t u = blob_read_uint32(blob);
+ union packed_type encoded;
+ encoded.u32 = blob_read_uint32(blob);
- if (u == 0) {
+ if (encoded.u32 == 0) {
return NULL;
}
- glsl_base_type base_type = (glsl_base_type) (u >> 24);
+ glsl_base_type base_type = (glsl_base_type)encoded.basic.base_type;
switch (base_type) {
case GLSL_TYPE_UINT:
@@ -2694,20 +2711,22 @@ decode_type_from_blob(struct blob_reader *blob)
case GLSL_TYPE_INT64:
case GLSL_TYPE_BOOL: {
unsigned explicit_stride = blob_read_uint32(blob);
- return glsl_type::get_instance(base_type, (u >> 4) & 0x0f, u & 0x0f,
- explicit_stride, (u >> 10) & 0x1);
+ return glsl_type::get_instance(base_type, encoded.basic.vector_elements,
+ encoded.basic.matrix_columns,
+ explicit_stride,
+ encoded.basic.interface_row_major);
}
case GLSL_TYPE_SAMPLER:
- return glsl_type::get_sampler_instance((enum glsl_sampler_dim) ((u >> 4) & 0x0f),
- (u >> 3) & 0x01,
- (u >> 2) & 0x01,
- (glsl_base_type) ((u >> 0) & 0x03));
+ return glsl_type::get_sampler_instance((enum glsl_sampler_dim)encoded.sampler.dimensionality,
+ encoded.sampler.shadow,
+ encoded.sampler.array,
+ (glsl_base_type) encoded.sampler.sampled_type);
case GLSL_TYPE_SUBROUTINE:
return glsl_type::get_subroutine_instance(blob_read_string(blob));
case GLSL_TYPE_IMAGE:
- return glsl_type::get_image_instance((enum glsl_sampler_dim) ((u >> 3) & 0x0f),
- (u >> 2) & 0x01,
- (glsl_base_type) ((u >> 0) & 0x03));
+ return glsl_type::get_image_instance((enum glsl_sampler_dim)encoded.sampler.dimensionality,
+ encoded.sampler.array,
+ (glsl_base_type) encoded.sampler.sampled_type);
case GLSL_TYPE_ATOMIC_UINT:
return glsl_type::atomic_uint_type;
case GLSL_TYPE_ARRAY: {
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