[Mesa-dev] [PATCH 2/6] glsl: Linker support for ARB_shader_atomic_counters.

Paul Berry stereotype441 at gmail.com
Fri Nov 1 10:06:36 PDT 2013


On 29 October 2013 16:37, Francisco Jerez <currojerez at riseup.net> wrote:

> v2: Add comments on the purpose of the auxiliary data structures.
>     Check for atomic counter overlaps.  Use the contains_atomic()
>     convenience method.  Add static assert with the number of expected
>     shader stages.
>
> v3: Don't resize atomic arrays.
> ---
>  src/glsl/Makefile.sources |   1 +
>  src/glsl/link_atomics.cpp | 237
> ++++++++++++++++++++++++++++++++++++++++++++++
>  src/glsl/linker.cpp       |  17 +++-
>  src/glsl/linker.h         |   7 ++
>  4 files changed, 261 insertions(+), 1 deletion(-)
>  create mode 100644 src/glsl/link_atomics.cpp
>
> diff --git a/src/glsl/Makefile.sources b/src/glsl/Makefile.sources
> index 2f7bfa1..197d081 100644
> --- a/src/glsl/Makefile.sources
> +++ b/src/glsl/Makefile.sources
> @@ -47,6 +47,7 @@ LIBGLSL_FILES = \
>         $(GLSL_SRCDIR)/ir_validate.cpp \
>         $(GLSL_SRCDIR)/ir_variable_refcount.cpp \
>         $(GLSL_SRCDIR)/linker.cpp \
> +       $(GLSL_SRCDIR)/link_atomics.cpp \
>         $(GLSL_SRCDIR)/link_functions.cpp \
>         $(GLSL_SRCDIR)/link_interface_blocks.cpp \
>         $(GLSL_SRCDIR)/link_uniforms.cpp \
> diff --git a/src/glsl/link_atomics.cpp b/src/glsl/link_atomics.cpp
> new file mode 100644
> index 0000000..5a3d769
> --- /dev/null
> +++ b/src/glsl/link_atomics.cpp
> @@ -0,0 +1,237 @@
> +/*
> + * Copyright © 2013 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.
> + */
> +
> +#include <map>
> +
> +#include "ir.h"
> +#include "ir_uniform.h"
> +#include "linker.h"
> +#include "program/hash_table.h"
> +
> +namespace {
> +   /*
> +    * Atomic counter as seen by the program.
> +    */
> +   struct active_atomic_counter {
> +      active_atomic_counter() : id(), var() {}
> +      active_atomic_counter(unsigned id, ir_variable *var) :
> +         id(id), var(var) {}
> +
> +      unsigned id;
> +      ir_variable *var;
> +   };
> +
> +   /**
> +    * Active atomic buffer indexed by offset.
> +    */
> +   typedef std::map<unsigned, active_atomic_counter>
> active_atomic_counters_t;
> +
> +   /*
> +    * Atomic counter buffer referenced by the program.  There is a one
> +    * to one correspondence between these and the objects that can be
> +    * queried using glGetActiveAtomicCounterBufferiv().
> +    */
> +   struct active_atomic_buffer {
> +      active_atomic_buffer() : stage_references(), size(0) {}
> +
> +      active_atomic_counters_t counters;
> +      unsigned stage_references[MESA_SHADER_TYPES];
> +      unsigned size;
> +   };
> +
> +   /**
> +    * Active atomic buffer indexed by binding point.
> +    */
> +   typedef std::map<unsigned, active_atomic_buffer>
> active_atomic_buffers_t;
> +
> +   bool
> +   check_atomic_counters_overlap(const ir_variable *x, const ir_variable
> *y)
> +   {
> +      return ((x->atomic.offset >= y->atomic.offset &&
> +               x->atomic.offset < y->atomic.offset +
> y->type->atomic_size()) ||
> +              (y->atomic.offset >= x->atomic.offset &&
> +               y->atomic.offset < x->atomic.offset +
> x->type->atomic_size()));
> +   }
> +
> +   bool
> +   check_atomic_counter_location(const active_atomic_buffer &ab,
> +                                 const ir_variable *var)
> +   {
> +      active_atomic_counters_t::const_iterator adjacent =
> +         ab.counters.upper_bound(var->atomic.offset);
> +
> +      if ((adjacent != ab.counters.end() &&
> +           check_atomic_counters_overlap(adjacent->second.var, var)) ||
> +          (adjacent != ab.counters.begin() &&
> +           check_atomic_counters_overlap((--adjacent)->second.var, var)))
> {
> +         /* Overlapping counter found, it must be a reference to the
> +          * same counter from a different shader stage.
> +          */
> +         return !strcmp(var->name, adjacent->second.var->name);
>

Personally I prefer "strcmp(...) == 0" to "!strcmp(...)" because with the
latter, I'm liable to accidentally turn it around in my brain and think it
means "strings not equal".  But I won't be a stickler about it.


> +      } else {
> +         return true;
> +      }
> +   }
> +
> +   active_atomic_buffers_t
> +   find_active_atomic_counters(struct gl_shader_program *prog)
> +   {
> +      active_atomic_buffers_t abs;
> +
> +      for (unsigned i = 0; i < MESA_SHADER_TYPES; ++i) {
> +         struct gl_shader *sh = prog->_LinkedShaders[i];
> +         if (sh == NULL)
> +            continue;
> +
> +         foreach_list(node, sh->ir) {
> +            ir_variable *var = ((ir_instruction *)node)->as_variable();
> +
> +            if (var && var->type->contains_atomic()) {
> +               unsigned id;
> +               bool found = prog->UniformHash->get(id, var->name);
> +               assert(found);
> +               active_atomic_buffer &ab = abs[var->binding];
> +
> +               if (check_atomic_counter_location(ab, var)) {
> +                  ab.counters[var->atomic.offset] =
> +                     active_atomic_counter(id, var);
> +                  ab.stage_references[i]++;
> +                  ab.size = std::max(ab.size, var->atomic.offset +
> +                                     var->type->atomic_size());
> +               } else {
> +                  linker_error(prog, "Atomic counter %s declared at
> offset %d "
> +                               "which is already in use.", var->name,
> +                               var->atomic.offset);
> +               }
> +            }
> +         }
> +      }
> +
> +      return abs;
> +   }
> +}
> +
> +void
> +link_assign_atomic_counter_resources(struct gl_shader_program *prog)
> +{
> +   active_atomic_buffers_t abs = find_active_atomic_counters(prog);
> +
> +   prog->AtomicBuffers = rzalloc_array(prog, gl_active_atomic_buffer,
> +                                       abs.size());
> +   prog->NumAtomicBuffers = abs.size();
> +
> +   unsigned i = 0;
> +   for (active_atomic_buffers_t::iterator it = abs.begin();
> +        it != abs.end(); ++it, ++i) {
> +      active_atomic_buffer &ab = it->second;
> +      gl_active_atomic_buffer &mab = prog->AtomicBuffers[i];
> +
> +      /* Assign buffer-specific fields. */
> +      mab.Binding = it->first;
> +      mab.MinimumSize = ab.size;
> +      mab.Uniforms = rzalloc_array(prog->AtomicBuffers, GLuint,
> +                                   ab.counters.size());
> +      mab.NumUniforms = ab.counters.size();
> +
> +      /* Assign counter-specific fields. */
> +      unsigned j = 0;
> +      for (active_atomic_counters_t::iterator jt = ab.counters.begin();
> +           jt != ab.counters.end(); ++jt, ++j) {
> +         ir_variable *var = jt->second.var;
> +         gl_uniform_storage &storage = prog->UniformStorage[jt->second.id
> ];
> +
> +         mab.Uniforms[j] = jt->second.id;
> +         var->atomic.buffer_index = i;
> +         storage.atomic_buffer_index = i;
> +         storage.offset = var->atomic.offset;
> +         storage.array_stride = (var->type->is_array() ?
> +                                 var->type->element_type()->atomic_size()
> : 0);
> +      }
> +
> +      /* Assign stage-specific fields. */
> +      for (j = 0; j < MESA_SHADER_TYPES; ++j)
> +         mab.StageReferences[j] =
> +            (ab.stage_references[j] ? GL_TRUE : GL_FALSE);
> +   }
> +}
> +
> +void
> +link_check_atomic_counter_resources(struct gl_context *ctx,
> +                                    struct gl_shader_program *prog)
> +{
> +   STATIC_ASSERT(MESA_SHADER_TYPES == 3);
> +   static const char *shader_names[MESA_SHADER_TYPES] = {
> +      "vertex", "geometry", "fragment"
> +   };
> +   const unsigned max_atomic_counters[MESA_SHADER_TYPES] = {
> +      ctx->Const.VertexProgram.MaxAtomicCounters,
> +      ctx->Const.GeometryProgram.MaxAtomicCounters,
> +      ctx->Const.FragmentProgram.MaxAtomicCounters
> +   };
> +   const unsigned max_atomic_buffers[MESA_SHADER_TYPES] = {
> +      ctx->Const.VertexProgram.MaxAtomicBuffers,
> +      ctx->Const.GeometryProgram.MaxAtomicBuffers,
> +      ctx->Const.FragmentProgram.MaxAtomicBuffers
> +   };
> +   active_atomic_buffers_t abs = find_active_atomic_counters(prog);
> +   unsigned atomic_counters[MESA_SHADER_TYPES] = {};
> +   unsigned atomic_buffers[MESA_SHADER_TYPES] = {};
> +   unsigned total_atomic_counters = 0;
> +   unsigned total_atomic_buffers = 0;
> +
> +   /* Sum the required resources.  Note that this counts buffers and
> +    * counters referenced by several shader stages multiple times
> +    * against the combined limit -- That's the behavior the spec
> +    * requires.
> +    */
> +   for (active_atomic_buffers_t::iterator it = abs.begin();
> +        it != abs.end(); ++it) {
> +      for (unsigned j = 0; j < MESA_SHADER_TYPES; ++j) {
> +         const unsigned n = it->second.stage_references[j];
> +
> +         if (n) {
> +            atomic_counters[j] += n;
> +            total_atomic_counters += n;
> +            atomic_buffers[j]++;
> +            total_atomic_buffers++;
> +         }
> +      }
> +   }
> +
> +   /* Check that they are within the supported limits. */
> +   for (unsigned i = 0; i < MESA_SHADER_TYPES; i++) {
> +      if (atomic_counters[i] > max_atomic_counters[i])
> +         linker_error(prog, "Too many %s shader atomic counters",
> +                      shader_names[i]);
> +
> +      if (atomic_buffers[i] > max_atomic_buffers[i])
> +         linker_error(prog, "Too many %s shader atomic counter buffers",
> +                      shader_names[i]);
> +   }
> +
> +   if (total_atomic_counters > ctx->Const.MaxCombinedAtomicCounters)
> +      linker_error(prog, "Too many combined atomic counters");
> +
> +   if (total_atomic_buffers > ctx->Const.MaxCombinedAtomicBuffers)
> +      linker_error(prog, "Too many combined atomic buffers");
> +}
> diff --git a/src/glsl/linker.cpp b/src/glsl/linker.cpp
> index 495a2ab..bbff2b7 100644
> --- a/src/glsl/linker.cpp
> +++ b/src/glsl/linker.cpp
> @@ -674,6 +674,14 @@ cross_validate_globals(struct gl_shader_program *prog,
>                 existing->explicit_binding = true;
>              }
>
> +            if (var->type->contains_atomic() &&
> +                var->atomic.offset != existing->atomic.offset) {
> +               linker_error(prog, "offset specifications for %s "
> +                            "`%s' have differing values\n",
> +                            mode_string(var), var->name);
> +               return;
> +            }
> +
>             /* Validate layout qualifiers for gl_FragDepth.
>              *
>              * From the AMD/ARB_conservative_depth specs:
> @@ -1509,7 +1517,7 @@ update_array_sizes(struct gl_shader_program *prog)
>           * will not be eliminated.  Since we always do std140, just
>           * don't resize arrays in UBOs.
>           */
> -        if (var->is_in_uniform_block())
> +        if (var->is_in_uniform_block() || var->type->contains_atomic())
>

Can you please update the comment above this "if" statement to explain why
we're not resizing arrays containing atomics?

WIth that change, the patch is:

Reviewed-by: Paul Berry <stereotype441 at gmail.com>

As with the previous patch, I don't think we can land this until we resolve
the open question about whether STL is allowed in Mesa.


>             continue;
>
>          unsigned int size = var->max_array_access;
> @@ -2014,6 +2022,10 @@ link_shaders(struct gl_context *ctx, struct
> gl_shader_program *prog)
>        prog->UniformBlockStageIndex[i] = NULL;
>     }
>
> +   ralloc_free(prog->AtomicBuffers);
> +   prog->AtomicBuffers = NULL;
> +   prog->NumAtomicBuffers = 0;
> +
>     /* Separate the shaders into groups based on their type.
>      */
>     struct gl_shader **vert_shader_list;
> @@ -2365,9 +2377,12 @@ link_shaders(struct gl_context *ctx, struct
> gl_shader_program *prog)
>
>     update_array_sizes(prog);
>     link_assign_uniform_locations(prog);
> +   link_assign_atomic_counter_resources(prog);
>     store_fragdepth_layout(prog);
>
>     check_resources(ctx, prog);
> +   link_check_atomic_counter_resources(ctx, prog);
> +
>     if (!prog->LinkStatus)
>        goto done;
>
> diff --git a/src/glsl/linker.h b/src/glsl/linker.h
> index 887cd33..3380151 100644
> --- a/src/glsl/linker.h
> +++ b/src/glsl/linker.h
> @@ -69,6 +69,13 @@ validate_interstage_interface_blocks(struct
> gl_shader_program *prog,
>                                       const gl_shader *producer,
>                                       const gl_shader *consumer);
>
> +extern void
> +link_assign_atomic_counter_resources(struct gl_shader_program *prog);
> +
> +extern void
> +link_check_atomic_counter_resources(struct gl_context *ctx,
> +                                    struct gl_shader_program *prog);
> +
>  /**
>   * Class for processing all of the leaf fields of a variable that
> corresponds
>   * to a program resource.
> --
> 1.8.3.4
>
> _______________________________________________
> mesa-dev mailing list
> mesa-dev at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/mesa-dev
>
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