[Mesa-dev] [PATCH 00/18] ARB_gl_spirv series 3: support for atomic counters

[Alejandro Piñeiro]

Hi,

this is the third series for the ongoing support for ARB_gl_spirv. The
main focus of this series is providing support for atomic
counters. More than half of the patches are for spirv/nir, as atomic
counters is a feature not included on Vulkan.

Note that the need of supporting atomic counters has somewhat
flip-flopped on different specs. In the practice it is basically a
deprecated feature, that lead to be explicitly removed from
GL_KHR_vulkan_glsl. But although ARB_gl_spirv uses GL_KHR_vulkan_glsl
as reference for the mapping of GLSL->SPIR-V features needed to be
supported, atomic counters got explicitly re-introduced with
ARB_gl_spirv. From ARB_gl_spirv spec:

    "Corresponding features that GLSL keeps, despite GL_KHR_vulkan_glsl removal:
      * default uniforms (those not inside a uniform block)
      * atomic-counter bindings have the /offset/ layout qualifier"

Another characteristic of atomic counters is that they lack explicit
location. From ARB_shader_atomics_counters spec:

    "Unlike other user-defined uniforms declared at global scope, they
     take NO storage from the default partition, they have NO
     location, and they may NOT be set with the Uniform* commands.
     Atomic counters may also NOT be grouped into uniform blocks."

so it is an exception of the general ARB_gl_spirv rule "explicit
location for uniforms are mandatory". This series implements at the
nir/linker the ability to set a location for uniforms without a
location.

The tree for this series can be found on the following repository:

   * https://github.com/Igalia/mesa/tree/arb_gl_spirv-series3-atomics-counters-v1

and we provide some atomic-counter tests for the extension here
(although it would be needed to use MESA_EXTENSION_OVERRIDE):

   * https://github.com/Igalia/piglit/commits/arb_gl_spirv-series2-atomic-counters-v1


Alejandro Piñeiro (11):
  nir/linker: handle uniforms without explicit location
  compiler/glsl: refactor empty_uniform_block utilities to linker_util
  nir/linker: use empty block info to assign uniform locations
  spirv/nir: SpvStorageClassAtomicCounter support on
    vtn_storage_class_to_mode
  spirv/nir: add offset at vtn_variable
  nir_types: add glsl_atomic_uint_type() helper
  spirv/nir: tweak nir type when storage class is
    SpvStorageClassAtomicCounter
  spirv/nir: initialize offset on the nir var at vtn_create_variable
  spirv/nir: add atomic counter support on
    vtn_handle_ssbo_or_shared_atomic
  spirv/nir: add capability check for SpvCapabilityAtomicStorage
  i965: enable AtomicStorage capability for gen7+

Antia Puentes (4):
  compiler: utility to get the depth of multidimensional array
  nir/spirv: Fix atomic counter (multidimensional-)arrays
  nir: Fix OpAtomicCounterIDecrement for uniform atomic counters
  mesa/glspirv: lower workgroup access to offsets

Neil Roberts (3):
  nir/types: Add wrappers for a couple of atomic counter methods
  nir/linker: Add a pure NIR implementation of the atomic counter linker
  i965: Use the new nir atomic counter linker for SPIR-V shaders

 src/compiler/Makefile.sources                |   1 +
 src/compiler/glsl/gl_nir_link_atomics.c      | 282 +++++++++++++++++++++++++++
 src/compiler/glsl/gl_nir_link_uniforms.c     |  64 +++++-
 src/compiler/glsl/gl_nir_linker.h            |   3 +
 src/compiler/glsl/gl_nir_lower_atomics.c     |   8 +-
 src/compiler/glsl/glsl_to_nir.cpp            |   4 +-
 src/compiler/glsl/link_uniforms.cpp          |  34 +---
 src/compiler/glsl/linker.cpp                 |  19 +-
 src/compiler/glsl/linker.h                   |  13 --
 src/compiler/glsl/linker_util.cpp            |  55 ++++++
 src/compiler/glsl/linker_util.h              |  21 ++
 src/compiler/glsl/meson.build                |   1 +
 src/compiler/glsl_types.h                    |  15 ++
 src/compiler/nir/nir_intrinsics.py           |   3 +-
 src/compiler/nir/nir_lower_atomics_to_ssbo.c |   8 +-
 src/compiler/nir_types.cpp                   |  24 +++
 src/compiler/nir_types.h                     |   7 +
 src/compiler/shader_info.h                   |   1 +
 src/compiler/spirv/spirv_to_nir.c            |  95 ++++++++-
 src/compiler/spirv/vtn_private.h             |   1 +
 src/compiler/spirv/vtn_variables.c           |  55 +++++-
 src/mesa/drivers/dri/i965/brw_context.c      |   1 +
 src/mesa/drivers/dri/i965/brw_link.cpp       |   2 +
 src/mesa/main/glspirv.c                      |   1 +
 24 files changed, 636 insertions(+), 82 deletions(-)
 create mode 100644 src/compiler/glsl/gl_nir_link_atomics.c

-- 
2.14.1