src/compiler/nir/nir_intrinsics.py

   1 #
   2 # Copyright (C) 2018 Red Hat
   3 # Copyright (C) 2014 Intel Corporation
   4 #
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  14 # Software.
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  17 # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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  21 # FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  22 # IN THE SOFTWARE.
  23 #
  24
  25 # This file defines all the available intrinsics in one place.
  26 #
  27 # The Intrinsic class corresponds one-to-one with nir_intrinsic_info
  28 # structure.
  29
  30 class Intrinsic(object):
  31    """Class that represents all the information about an intrinsic opcode.
  32    NOTE: this must be kept in sync with nir_intrinsic_info.
  33    """
  34    def __init__(self, name, src_components, dest_components, num_variables,
  35                 indices, flags, sysval):
  36        """Parameters:
  37
  38        - name: the intrinsic name
  39        - src_components: list of the number of components per src, 0 means
  40          vectorized instruction with number of components given in the
  41          num_components field in nir_intrinsic_instr.
  42        - dest_components: number of destination components, -1 means no
  43          dest, 0 means number of components given in num_components field
  44          in nir_intrinsic_instr.
  45        - num_variables: the number of variables
  46        - indices: list of constant indicies
  47        - flags: list of semantic flags
  48        - sysval: is this a system-value intrinsic
  49        """
  50        assert isinstance(name, str)
  51        assert isinstance(src_components, list)
  52        if src_components:
  53            assert isinstance(src_components[0], int)
  54        assert isinstance(dest_components, int)
  55        assert isinstance(num_variables, int)
  56        assert isinstance(indices, list)
  57        if indices:
  58            assert isinstance(indices[0], str)
  59        assert isinstance(flags, list)
  60        if flags:
  61            assert isinstance(flags[0], str)
  62        assert isinstance(sysval, bool)
  63
  64        self.name = name
  65        self.num_srcs = len(src_components)
  66        self.src_components = src_components
  67        self.has_dest = (dest_components >= 0)
  68        self.dest_components = dest_components
  69        self.num_variables = num_variables
  70        self.num_indices = len(indices)
  71        self.indices = indices
  72        self.flags = flags
  73        self.sysval = sysval
  74
  75 #
  76 # Possible indices:
  77 #
  78
  79 # A constant 'base' value that is added to an offset src:
  80 BASE = "NIR_INTRINSIC_BASE"
  81 # For store instructions, a writemask:
  82 WRMASK = "NIR_INTRINSIC_WRMASK"
  83 # The stream-id for GS emit_vertex/end_primitive intrinsics:
  84 STREAM_ID = "NIR_INTRINSIC_STREAM_ID"
  85 # The clip-plane id for load_user_clip_plane intrinsics:
  86 UCP_ID = "NIR_INTRINSIC_UCP_ID"
  87 # The amount of data, starting from BASE, that this instruction
  88 # may access.  This is used to provide bounds if the offset is
  89 # not constant.
  90 RANGE = "NIR_INTRINSIC_RANGE"
  91 # The vulkan descriptor set binding for vulkan_resource_index
  92 # intrinsic
  93 DESC_SET = "NIR_INTRINSIC_DESC_SET"
  94 # The vulkan descriptor set binding for vulkan_resource_index
  95 # intrinsic
  96 BINDING = "NIR_INTRINSIC_BINDING"
  97 # Component offset
  98 COMPONENT = "NIR_INTRINSIC_COMPONENT"
  99 # Interpolation mode (only meaningful for FS inputs)
 100 INTERP_MODE = "NIR_INTRINSIC_INTERP_MODE"
 101 # A binary nir_op to use when performing a reduction or scan operation
 102 REDUCTION_OP = "NIR_INTRINSIC_REDUCTION_OP"
 103 # Cluster size for reduction operations
 104 CLUSTER_SIZE = "NIR_INTRINSIC_CLUSTER_SIZE"
 105
 106 #
 107 # Possible flags:
 108 #
 109
 110 CAN_ELIMINATE = "NIR_INTRINSIC_CAN_ELIMINATE"
 111 CAN_REORDER   = "NIR_INTRINSIC_CAN_REORDER"
 112
 113 INTR_OPCODES = {}
 114
 115 def intrinsic(name, src_comp=[], dest_comp=-1, num_vars=0, indices=[],
 116               flags=[], sysval=False):
 117     assert name not in INTR_OPCODES
 118     INTR_OPCODES[name] = Intrinsic(name, src_comp, dest_comp, num_vars,
 119                                    indices, flags, sysval)
 120
 121 intrinsic("nop", flags=[CAN_ELIMINATE])
 122
 123 intrinsic("load_var", dest_comp=0, num_vars=1, flags=[CAN_ELIMINATE])
 124 intrinsic("store_var", src_comp=[0], num_vars=1, indices=[WRMASK])
 125 intrinsic("copy_var", num_vars=2)
 126
 127 # Interpolation of input.  The interp_var_at* intrinsics are similar to the
 128 # load_var intrinsic acting on a shader input except that they interpolate
 129 # the input differently.  The at_sample and at_offset intrinsics take an
 130 # additional source that is an integer sample id or a vec2 position offset
 131 # respectively.
 132
 133 intrinsic("interp_var_at_centroid", dest_comp=0, num_vars=1,
 134           flags=[ CAN_ELIMINATE, CAN_REORDER])
 135 intrinsic("interp_var_at_sample", src_comp=[1], dest_comp=0, num_vars=1,
 136           flags=[CAN_ELIMINATE, CAN_REORDER])
 137 intrinsic("interp_var_at_offset", src_comp=[2], dest_comp=0, num_vars=1,
 138           flags=[CAN_ELIMINATE, CAN_REORDER])
 139
 140 # Ask the driver for the size of a given buffer. It takes the buffer index
 141 # as source.
 142 intrinsic("get_buffer_size", src_comp=[1], dest_comp=1,
 143           flags=[CAN_ELIMINATE, CAN_REORDER])
 144
 145 # a barrier is an intrinsic with no inputs/outputs but which can't be moved
 146 # around/optimized in general
 147 def barrier(name):
 148     intrinsic(name)
 149
 150 barrier("barrier")
 151 barrier("discard")
 152
 153 # Memory barrier with semantics analogous to the memoryBarrier() GLSL
 154 # intrinsic.
 155 barrier("memory_barrier")
 156
 157 # Shader clock intrinsic with semantics analogous to the clock2x32ARB()
 158 # GLSL intrinsic.
 159 # The latter can be used as code motion barrier, which is currently not
 160 # feasible with NIR.
 161 intrinsic("shader_clock", dest_comp=2, flags=[CAN_ELIMINATE])
 162
 163 # Shader ballot intrinsics with semantics analogous to the
 164 #
 165 #    ballotARB()
 166 #    readInvocationARB()
 167 #    readFirstInvocationARB()
 168 #
 169 # GLSL functions from ARB_shader_ballot.
 170 intrinsic("ballot", src_comp=[1], dest_comp=0, flags=[CAN_ELIMINATE])
 171 intrinsic("read_invocation", src_comp=[0, 1], dest_comp=0, flags=[CAN_ELIMINATE])
 172 intrinsic("read_first_invocation", src_comp=[0], dest_comp=0, flags=[CAN_ELIMINATE])
 173
 174 # Additional SPIR-V ballot intrinsics
 175 #
 176 # These correspond to the SPIR-V opcodes
 177 #
 178 #    OpGroupUniformElect
 179 #    OpSubgroupFirstInvocationKHR
 180 intrinsic("elect", dest_comp=1, flags=[CAN_ELIMINATE])
 181 intrinsic("first_invocation", dest_comp=1, flags=[CAN_ELIMINATE])
 182
 183 # Memory barrier with semantics analogous to the compute shader
 184 # groupMemoryBarrier(), memoryBarrierAtomicCounter(), memoryBarrierBuffer(),
 185 # memoryBarrierImage() and memoryBarrierShared() GLSL intrinsics.
 186 barrier("group_memory_barrier")
 187 barrier("memory_barrier_atomic_counter")
 188 barrier("memory_barrier_buffer")
 189 barrier("memory_barrier_image")
 190 barrier("memory_barrier_shared")
 191 barrier("begin_invocation_interlock")
 192 barrier("end_invocation_interlock")
 193
 194 # A conditional discard, with a single boolean source.
 195 intrinsic("discard_if", src_comp=[1])
 196
 197 # ARB_shader_group_vote intrinsics
 198 intrinsic("vote_any", src_comp=[1], dest_comp=1, flags=[CAN_ELIMINATE])
 199 intrinsic("vote_all", src_comp=[1], dest_comp=1, flags=[CAN_ELIMINATE])
 200 intrinsic("vote_feq", src_comp=[0], dest_comp=1, flags=[CAN_ELIMINATE])
 201 intrinsic("vote_ieq", src_comp=[0], dest_comp=1, flags=[CAN_ELIMINATE])
 202
 203 # Ballot ALU operations from SPIR-V.
 204 #
 205 # These operations work like their ALU counterparts except that the operate
 206 # on a uvec4 which is treated as a 128bit integer.  Also, they are, in
 207 # general, free to ignore any bits which are above the subgroup size.
 208 intrinsic("ballot_bitfield_extract", src_comp=[4, 1], dest_comp=1, flags=[CAN_ELIMINATE])
 209 intrinsic("ballot_bit_count_reduce", src_comp=[4], dest_comp=1, flags=[CAN_ELIMINATE])
 210 intrinsic("ballot_bit_count_inclusive", src_comp=[4], dest_comp=1, flags=[CAN_ELIMINATE])
 211 intrinsic("ballot_bit_count_exclusive", src_comp=[4], dest_comp=1, flags=[CAN_ELIMINATE])
 212 intrinsic("ballot_find_lsb", src_comp=[4], dest_comp=1, flags=[CAN_ELIMINATE])
 213 intrinsic("ballot_find_msb", src_comp=[4], dest_comp=1, flags=[CAN_ELIMINATE])
 214
 215 # Shuffle operations from SPIR-V.
 216 intrinsic("shuffle", src_comp=[0, 1], dest_comp=0, flags=[CAN_ELIMINATE])
 217 intrinsic("shuffle_xor", src_comp=[0, 1], dest_comp=0, flags=[CAN_ELIMINATE])
 218 intrinsic("shuffle_up", src_comp=[0, 1], dest_comp=0, flags=[CAN_ELIMINATE])
 219 intrinsic("shuffle_down", src_comp=[0, 1], dest_comp=0, flags=[CAN_ELIMINATE])
 220
 221 # Quad operations from SPIR-V.
 222 intrinsic("quad_broadcast", src_comp=[0, 1], dest_comp=0, flags=[CAN_ELIMINATE])
 223 intrinsic("quad_swap_horizontal", src_comp=[0], dest_comp=0, flags=[CAN_ELIMINATE])
 224 intrinsic("quad_swap_vertical", src_comp=[0], dest_comp=0, flags=[CAN_ELIMINATE])
 225 intrinsic("quad_swap_diagonal", src_comp=[0], dest_comp=0, flags=[CAN_ELIMINATE])
 226
 227 intrinsic("reduce", src_comp=[0], dest_comp=0, indices=[REDUCTION_OP, CLUSTER_SIZE],
 228           flags=[CAN_ELIMINATE])
 229 intrinsic("inclusive_scan", src_comp=[0], dest_comp=0, indices=[REDUCTION_OP],
 230           flags=[CAN_ELIMINATE])
 231 intrinsic("exclusive_scan", src_comp=[0], dest_comp=0, indices=[REDUCTION_OP],
 232           flags=[CAN_ELIMINATE])
 233
 234 # Basic Geometry Shader intrinsics.
 235 #
 236 # emit_vertex implements GLSL's EmitStreamVertex() built-in.  It takes a single
 237 # index, which is the stream ID to write to.
 238 #
 239 # end_primitive implements GLSL's EndPrimitive() built-in.
 240 intrinsic("emit_vertex",   indices=[STREAM_ID])
 241 intrinsic("end_primitive", indices=[STREAM_ID])
 242
 243 # Geometry Shader intrinsics with a vertex count.
 244 #
 245 # Alternatively, drivers may implement these intrinsics, and use
 246 # nir_lower_gs_intrinsics() to convert from the basic intrinsics.
 247 #
 248 # These maintain a count of the number of vertices emitted, as an additional
 249 # unsigned integer source.
 250 intrinsic("emit_vertex_with_counter", src_comp=[1], indices=[STREAM_ID])
 251 intrinsic("end_primitive_with_counter", src_comp=[1], indices=[STREAM_ID])
 252 intrinsic("set_vertex_count", src_comp=[1])
 253
 254 # Atomic counters
 255 #
 256 # The *_var variants take an atomic_uint nir_variable, while the other,
 257 # lowered, variants take a constant buffer index and register offset.
 258
 259 def atomic(name, flags=[]):
 260     intrinsic(name + "_var", dest_comp=1, num_vars=1, flags=flags)
 261     intrinsic(name, src_comp=[1], dest_comp=1, indices=[BASE], flags=flags)
 262
 263 def atomic2(name):
 264     intrinsic(name + "_var", src_comp=[1], dest_comp=1, num_vars=1)
 265     intrinsic(name, src_comp=[1, 1], dest_comp=1, indices=[BASE])
 266
 267 def atomic3(name):
 268     intrinsic(name + "_var", src_comp=[1, 1], dest_comp=1, num_vars=1)
 269     intrinsic(name, src_comp=[1, 1, 1], dest_comp=1, indices=[BASE])
 270
 271 atomic("atomic_counter_inc")
 272 atomic("atomic_counter_dec")
 273 atomic("atomic_counter_read", flags=[CAN_ELIMINATE])
 274 atomic2("atomic_counter_add")
 275 atomic2("atomic_counter_min")
 276 atomic2("atomic_counter_max")
 277 atomic2("atomic_counter_and")
 278 atomic2("atomic_counter_or")
 279 atomic2("atomic_counter_xor")
 280 atomic2("atomic_counter_exchange")
 281 atomic3("atomic_counter_comp_swap")
 282
 283 # Image load, store and atomic intrinsics.
 284 #
 285 # All image intrinsics take an image target passed as a nir_variable.  Image
 286 # variables contain a number of memory and layout qualifiers that influence
 287 # the semantics of the intrinsic.
 288 #
 289 # All image intrinsics take a four-coordinate vector and a sample index as
 290 # first two sources, determining the location within the image that will be
 291 # accessed by the intrinsic.  Components not applicable to the image target
 292 # in use are undefined.  Image store takes an additional four-component
 293 # argument with the value to be written, and image atomic operations take
 294 # either one or two additional scalar arguments with the same meaning as in
 295 # the ARB_shader_image_load_store specification.
 296 intrinsic("image_var_load", src_comp=[4, 1], dest_comp=4, num_vars=1,
 297           flags=[CAN_ELIMINATE])
 298 intrinsic("image_var_store", src_comp=[4, 1, 4], num_vars=1)
 299 intrinsic("image_var_atomic_add",  src_comp=[4, 1, 1], dest_comp=1, num_vars=1)
 300 intrinsic("image_var_atomic_min",  src_comp=[4, 1, 1], dest_comp=1, num_vars=1)
 301 intrinsic("image_var_atomic_max",  src_comp=[4, 1, 1], dest_comp=1, num_vars=1)
 302 intrinsic("image_var_atomic_and",  src_comp=[4, 1, 1], dest_comp=1, num_vars=1)
 303 intrinsic("image_var_atomic_or",   src_comp=[4, 1, 1], dest_comp=1, num_vars=1)
 304 intrinsic("image_var_atomic_xor",  src_comp=[4, 1, 1], dest_comp=1, num_vars=1)
 305 intrinsic("image_var_atomic_exchange",  src_comp=[4, 1, 1], dest_comp=1, num_vars=1)
 306 intrinsic("image_var_atomic_comp_swap", src_comp=[4, 1, 1, 1], dest_comp=1, num_vars=1)
 307 intrinsic("image_var_size",    dest_comp=0, num_vars=1, flags=[CAN_ELIMINATE, CAN_REORDER])
 308 intrinsic("image_var_samples", dest_comp=1, num_vars=1, flags=[CAN_ELIMINATE, CAN_REORDER])
 309
 310 # Vulkan descriptor set intrinsics
 311 #
 312 # The Vulkan API uses a different binding model from GL.  In the Vulkan
 313 # API, all external resources are represented by a tuple:
 314 #
 315 # (descriptor set, binding, array index)
 316 #
 317 # where the array index is the only thing allowed to be indirect.  The
 318 # vulkan_surface_index intrinsic takes the descriptor set and binding as
 319 # its first two indices and the array index as its source.  The third
 320 # index is a nir_variable_mode in case that's useful to the backend.
 321 #
 322 # The intended usage is that the shader will call vulkan_surface_index to
 323 # get an index and then pass that as the buffer index ubo/ssbo calls.
 324 #
 325 # The vulkan_resource_reindex intrinsic takes a resource index in src0
 326 # (the result of a vulkan_resource_index or vulkan_resource_reindex) which
 327 # corresponds to the tuple (set, binding, index) and computes an index
 328 # corresponding to tuple (set, binding, idx + src1).
 329 intrinsic("vulkan_resource_index", src_comp=[1], dest_comp=1,
 330           indices=[DESC_SET, BINDING], flags=[CAN_ELIMINATE, CAN_REORDER])
 331 intrinsic("vulkan_resource_reindex", src_comp=[1, 1], dest_comp=1,
 332           flags=[CAN_ELIMINATE, CAN_REORDER])
 333
 334 # variable atomic intrinsics
 335 #
 336 # All of these variable atomic memory operations read a value from memory,
 337 # compute a new value using one of the operations below, write the new value
 338 # to memory, and return the original value read.
 339 #
 340 # All operations take 1 source except CompSwap that takes 2. These sources
 341 # represent:
 342 #
 343 # 0: The data parameter to the atomic function (i.e. the value to add
 344 #    in shared_atomic_add, etc).
 345 # 1: For CompSwap only: the second data parameter.
 346 #
 347 # All operations take 1 variable deref.
 348 intrinsic("var_atomic_add",  src_comp=[1], dest_comp=1, num_vars=1)
 349 intrinsic("var_atomic_imin", src_comp=[1], dest_comp=1, num_vars=1)
 350 intrinsic("var_atomic_umin", src_comp=[1], dest_comp=1, num_vars=1)
 351 intrinsic("var_atomic_imax", src_comp=[1], dest_comp=1, num_vars=1)
 352 intrinsic("var_atomic_umax", src_comp=[1], dest_comp=1, num_vars=1)
 353 intrinsic("var_atomic_and",  src_comp=[1], dest_comp=1, num_vars=1)
 354 intrinsic("var_atomic_or",   src_comp=[1], dest_comp=1, num_vars=1)
 355 intrinsic("var_atomic_xor",  src_comp=[1], dest_comp=1, num_vars=1)
 356 intrinsic("var_atomic_exchange", src_comp=[1], dest_comp=1, num_vars=1)
 357 intrinsic("var_atomic_comp_swap", src_comp=[1, 1], dest_comp=1, num_vars=1)
 358
 359 # SSBO atomic intrinsics
 360 #
 361 # All of the SSBO atomic memory operations read a value from memory,
 362 # compute a new value using one of the operations below, write the new
 363 # value to memory, and return the original value read.
 364 #
 365 # All operations take 3 sources except CompSwap that takes 4. These
 366 # sources represent:
 367 #
 368 # 0: The SSBO buffer index.
 369 # 1: The offset into the SSBO buffer of the variable that the atomic
 370 #    operation will operate on.
 371 # 2: The data parameter to the atomic function (i.e. the value to add
 372 #    in ssbo_atomic_add, etc).
 373 # 3: For CompSwap only: the second data parameter.
 374 intrinsic("ssbo_atomic_add",  src_comp=[1, 1, 1], dest_comp=1)
 375 intrinsic("ssbo_atomic_imin", src_comp=[1, 1, 1], dest_comp=1)
 376 intrinsic("ssbo_atomic_umin", src_comp=[1, 1, 1], dest_comp=1)
 377 intrinsic("ssbo_atomic_imax", src_comp=[1, 1, 1], dest_comp=1)
 378 intrinsic("ssbo_atomic_umax", src_comp=[1, 1, 1], dest_comp=1)
 379 intrinsic("ssbo_atomic_and",  src_comp=[1, 1, 1], dest_comp=1)
 380 intrinsic("ssbo_atomic_or",   src_comp=[1, 1, 1], dest_comp=1)
 381 intrinsic("ssbo_atomic_xor",  src_comp=[1, 1, 1], dest_comp=1)
 382 intrinsic("ssbo_atomic_exchange", src_comp=[1, 1, 1], dest_comp=1)
 383 intrinsic("ssbo_atomic_comp_swap", src_comp=[1, 1, 1, 1], dest_comp=1)
 384
 385 # CS shared variable atomic intrinsics
 386 #
 387 # All of the shared variable atomic memory operations read a value from
 388 # memory, compute a new value using one of the operations below, write the
 389 # new value to memory, and return the original value read.
 390 #
 391 # All operations take 2 sources except CompSwap that takes 3. These
 392 # sources represent:
 393 #
 394 # 0: The offset into the shared variable storage region that the atomic
 395 #    operation will operate on.
 396 # 1: The data parameter to the atomic function (i.e. the value to add
 397 #    in shared_atomic_add, etc).
 398 # 2: For CompSwap only: the second data parameter.
 399 intrinsic("shared_atomic_add",  src_comp=[1, 1], dest_comp=1, indices=[BASE])
 400 intrinsic("shared_atomic_imin", src_comp=[1, 1], dest_comp=1, indices=[BASE])
 401 intrinsic("shared_atomic_umin", src_comp=[1, 1], dest_comp=1, indices=[BASE])
 402 intrinsic("shared_atomic_imax", src_comp=[1, 1], dest_comp=1, indices=[BASE])
 403 intrinsic("shared_atomic_umax", src_comp=[1, 1], dest_comp=1, indices=[BASE])
 404 intrinsic("shared_atomic_and",  src_comp=[1, 1], dest_comp=1, indices=[BASE])
 405 intrinsic("shared_atomic_or",   src_comp=[1, 1], dest_comp=1, indices=[BASE])
 406 intrinsic("shared_atomic_xor",  src_comp=[1, 1], dest_comp=1, indices=[BASE])
 407 intrinsic("shared_atomic_exchange", src_comp=[1, 1], dest_comp=1, indices=[BASE])
 408 intrinsic("shared_atomic_comp_swap", src_comp=[1, 1, 1], dest_comp=1, indices=[BASE])
 409
 410 def system_value(name, dest_comp, indices=[]):
 411     intrinsic("load_" + name, [], dest_comp, 0, indices,
 412               flags=[CAN_ELIMINATE, CAN_REORDER], sysval=True)
 413
 414 system_value("frag_coord", 4)
 415 system_value("front_face", 1)
 416 system_value("vertex_id", 1)
 417 system_value("vertex_id_zero_base", 1)
 418 system_value("first_vertex", 1)
 419 system_value("is_indexed_draw", 1)
 420 system_value("base_vertex", 1)
 421 system_value("instance_id", 1)
 422 system_value("base_instance", 1)
 423 system_value("draw_id", 1)
 424 system_value("sample_id", 1)
 425 system_value("sample_pos", 2)
 426 system_value("sample_mask_in", 1)
 427 system_value("primitive_id", 1)
 428 system_value("invocation_id", 1)
 429 system_value("tess_coord", 3)
 430 system_value("tess_level_outer", 4)
 431 system_value("tess_level_inner", 2)
 432 system_value("patch_vertices_in", 1)
 433 system_value("local_invocation_id", 3)
 434 system_value("local_invocation_index", 1)
 435 system_value("work_group_id", 3)
 436 system_value("user_clip_plane", 4, indices=[UCP_ID])
 437 system_value("num_work_groups", 3)
 438 system_value("helper_invocation", 1)
 439 system_value("alpha_ref_float", 1)
 440 system_value("layer_id", 1)
 441 system_value("view_index", 1)
 442 system_value("subgroup_size", 1)
 443 system_value("subgroup_invocation", 1)
 444 system_value("subgroup_eq_mask", 0)
 445 system_value("subgroup_ge_mask", 0)
 446 system_value("subgroup_gt_mask", 0)
 447 system_value("subgroup_le_mask", 0)
 448 system_value("subgroup_lt_mask", 0)
 449 system_value("num_subgroups", 1)
 450 system_value("subgroup_id", 1)
 451 system_value("local_group_size", 3)
 452
 453 # Blend constant color values.  Float values are clamped.#
 454 system_value("blend_const_color_r_float", 1)
 455 system_value("blend_const_color_g_float", 1)
 456 system_value("blend_const_color_b_float", 1)
 457 system_value("blend_const_color_a_float", 1)
 458 system_value("blend_const_color_rgba8888_unorm", 1)
 459 system_value("blend_const_color_aaaa8888_unorm", 1)
 460
 461 # Barycentric coordinate intrinsics.
 462 #
 463 # These set up the barycentric coordinates for a particular interpolation.
 464 # The first three are for the simple cases: pixel, centroid, or per-sample
 465 # (at gl_SampleID).  The next two handle interpolating at a specified
 466 # sample location, or interpolating with a vec2 offset,
 467 #
 468 # The interp_mode index should be either the INTERP_MODE_SMOOTH or
 469 # INTERP_MODE_NOPERSPECTIVE enum values.
 470 #
 471 # The vec2 value produced by these intrinsics is intended for use as the
 472 # barycoord source of a load_interpolated_input intrinsic.
 473
 474 def barycentric(name, src_comp=[]):
 475     intrinsic("load_barycentric_" + name, src_comp=src_comp, dest_comp=2,
 476               indices=[INTERP_MODE], flags=[CAN_ELIMINATE, CAN_REORDER])
 477
 478 # no sources.  const_index[] = { interp_mode }
 479 barycentric("pixel")
 480 barycentric("centroid")
 481 barycentric("sample")
 482 # src[] = { sample_id }.  const_index[] = { interp_mode }
 483 barycentric("at_sample", [1])
 484 # src[] = { offset.xy }.  const_index[] = { interp_mode }
 485 barycentric("at_offset", [2])
 486
 487 # Load operations pull data from some piece of GPU memory.  All load
 488 # operations operate in terms of offsets into some piece of theoretical
 489 # memory.  Loads from externally visible memory (UBO and SSBO) simply take a
 490 # byte offset as a source.  Loads from opaque memory (uniforms, inputs, etc.)
 491 # take a base+offset pair where the base (const_index[0]) gives the location
 492 # of the start of the variable being loaded and and the offset source is a
 493 # offset into that variable.
 494 #
 495 # Uniform load operations have a second "range" index that specifies the
 496 # range (starting at base) of the data from which we are loading.  If
 497 # const_index[1] == 0, then the range is unknown.
 498 #
 499 # Some load operations such as UBO/SSBO load and per_vertex loads take an
 500 # additional source to specify which UBO/SSBO/vertex to load from.
 501 #
 502 # The exact address type depends on the lowering pass that generates the
 503 # load/store intrinsics.  Typically, this is vec4 units for things such as
 504 # varying slots and float units for fragment shader inputs.  UBO and SSBO
 505 # offsets are always in bytes.
 506
 507 def load(name, num_srcs, indices=[], flags=[]):
 508     intrinsic("load_" + name, [1] * num_srcs, dest_comp=0, indices=indices,
 509               flags=flags)
 510
 511 # src[] = { offset }. const_index[] = { base, range }
 512 load("uniform", 1, [BASE, RANGE], [CAN_ELIMINATE, CAN_REORDER])
 513 # src[] = { buffer_index, offset }. No const_index
 514 load("ubo", 2, flags=[CAN_ELIMINATE, CAN_REORDER])
 515 # src[] = { offset }. const_index[] = { base, component }
 516 load("input", 1, [BASE, COMPONENT], [CAN_ELIMINATE, CAN_REORDER])
 517 # src[] = { vertex, offset }. const_index[] = { base, component }
 518 load("per_vertex_input", 2, [BASE, COMPONENT], [CAN_ELIMINATE, CAN_REORDER])
 519 # src[] = { barycoord, offset }. const_index[] = { base, component }
 520 intrinsic("load_interpolated_input", src_comp=[2, 1], dest_comp=0,
 521           indices=[BASE, COMPONENT], flags=[CAN_ELIMINATE, CAN_REORDER])
 522
 523 # src[] = { buffer_index, offset }. No const_index
 524 load("ssbo", 2, flags=[CAN_ELIMINATE])
 525 # src[] = { offset }. const_index[] = { base, component }
 526 load("output", 1, [BASE, COMPONENT], flags=[CAN_ELIMINATE])
 527 # src[] = { vertex, offset }. const_index[] = { base }
 528 load("per_vertex_output", 2, [BASE, COMPONENT], [CAN_ELIMINATE])
 529 # src[] = { offset }. const_index[] = { base }
 530 load("shared", 1, [BASE], [CAN_ELIMINATE])
 531 # src[] = { offset }. const_index[] = { base, range }
 532 load("push_constant", 1, [BASE, RANGE], [CAN_ELIMINATE, CAN_REORDER])
 533
 534 # Stores work the same way as loads, except now the first source is the value
 535 # to store and the second (and possibly third) source specify where to store
 536 # the value.  SSBO and shared memory stores also have a write mask as
 537 # const_index[0].
 538
 539 def store(name, num_srcs, indices=[], flags=[]):
 540     intrinsic("store_" + name, [0] + ([1] * (num_srcs - 1)), indices=indices, flags=flags)
 541
 542 # src[] = { value, offset }. const_index[] = { base, write_mask, component }
 543 store("output", 2, [BASE, WRMASK, COMPONENT])
 544 # src[] = { value, vertex, offset }.
 545 # const_index[] = { base, write_mask, component }
 546 store("per_vertex_output", 3, [BASE, WRMASK, COMPONENT])
 547 # src[] = { value, block_index, offset }. const_index[] = { write_mask }
 548 store("ssbo", 3, [WRMASK])
 549 # src[] = { value, offset }. const_index[] = { base, write_mask }
 550 store("shared", 2, [BASE, WRMASK])