mesa/main: add support for ARB_compute_variable_groups_size

v5: - replace fixed_local_size by !LocalSizeVariable (Nicolai)
v4: - slightly indent spec quotes (Nicolai)
    - drop useless _mesa_has_compute_shaders() check (Nicolai)
    - move the fixed local size outside of the loop (Nicolai)
    - add missing check for invalid use of work group count
v2: - update formatting spec quotations (Ian)
    - move the total_invocations check outside of the loop (Ian)

Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>

11 files changed, 185 insertions, 1 deletions

diff --git a/src/mesa/main/api_validate.c b/src/mesa/main/api_validate.c
index 05691d2..c3c5a69 100644
--- a/src/mesa/main/api_validate.c
+++ b/src/mesa/main/api_validate.c
@@ -1285,6 +1285,7 @@ GLboolean
 _mesa_validate_DispatchCompute(struct gl_context *ctx,
                                const GLuint *num_groups)
 {
+   struct gl_shader_program *prog;
    int i;
    FLUSH_CURRENT(ctx, 0);
 
@@ -1317,6 +1318,101 @@ _mesa_validate_DispatchCompute(struct gl_context *ctx,
       }
    }
 
+   /* The ARB_compute_variable_group_size spec says:
+    *
+    * "An INVALID_OPERATION error is generated by DispatchCompute if the active
+    *  program for the compute shader stage has a variable work group size."
+    */
+   prog = ctx->_Shader->CurrentProgram[MESA_SHADER_COMPUTE];
+   if (prog->Comp.LocalSizeVariable) {
+      _mesa_error(ctx, GL_INVALID_OPERATION,
+                  "glDispatchCompute(variable work group size forbidden)");
+      return GL_FALSE;
+   }
+
+   return GL_TRUE;
+}
+
+GLboolean
+_mesa_validate_DispatchComputeGroupSizeARB(struct gl_context *ctx,
+                                           const GLuint *num_groups,
+                                           const GLuint *group_size)
+{
+   struct gl_shader_program *prog;
+   GLuint total_invocations = 1;
+   int i;
+
+   FLUSH_CURRENT(ctx, 0);
+
+   if (!check_valid_to_compute(ctx, "glDispatchComputeGroupSizeARB"))
+      return GL_FALSE;
+
+   /* The ARB_compute_variable_group_size spec says:
+    *
+    * "An INVALID_OPERATION error is generated by
+    *  DispatchComputeGroupSizeARB if the active program for the compute
+    *  shader stage has a fixed work group size."
+    */
+   prog = ctx->_Shader->CurrentProgram[MESA_SHADER_COMPUTE];
+   if (!prog->Comp.LocalSizeVariable) {
+      _mesa_error(ctx, GL_INVALID_OPERATION,
+                  "glDispatchComputeGroupSizeARB(fixed work group size "
+                  "forbidden)");
+      return GL_FALSE;
+   }
+
+   for (i = 0; i < 3; i++) {
+      /* The ARB_compute_variable_group_size spec says:
+       *
+       * "An INVALID_VALUE error is generated if any of num_groups_x,
+       *  num_groups_y and num_groups_z are greater than or equal to the
+       *  maximum work group count for the corresponding dimension."
+       */
+      if (num_groups[i] > ctx->Const.MaxComputeWorkGroupCount[i]) {
+         _mesa_error(ctx, GL_INVALID_VALUE,
+                     "glDispatchComputeGroupSizeARB(num_groups_%c)", 'x' + i);
+         return GL_FALSE;
+      }
+
+      /* The ARB_compute_variable_group_size spec says:
+       *
+       * "An INVALID_VALUE error is generated by DispatchComputeGroupSizeARB if
+       *  any of <group_size_x>, <group_size_y>, or <group_size_z> is less than
+       *  or equal to zero or greater than the maximum local work group size
+       *  for compute shaders with variable group size
+       *  (MAX_COMPUTE_VARIABLE_GROUP_SIZE_ARB) in the corresponding
+       *  dimension."
+       *
+       * However, the "less than" is a spec bug because they are declared as
+       * unsigned integers.
+       */
+      if (group_size[i] == 0 ||
+          group_size[i] > ctx->Const.MaxComputeVariableGroupSize[i]) {
+         _mesa_error(ctx, GL_INVALID_VALUE,
+                     "glDispatchComputeGroupSizeARB(group_size_%c)", 'x' + i);
+         return GL_FALSE;
+      }
+
+      total_invocations *= group_size[i];
+   }
+
+   /* The ARB_compute_variable_group_size spec says:
+    *
+    * "An INVALID_VALUE error is generated by DispatchComputeGroupSizeARB if
+    *  the product of <group_size_x>, <group_size_y>, and <group_size_z> exceeds
+    *  the implementation-dependent maximum local work group invocation count
+    *  for compute shaders with variable group size
+    *  (MAX_COMPUTE_VARIABLE_GROUP_INVOCATIONS_ARB)."
+    */
+   if (total_invocations > ctx->Const.MaxComputeVariableGroupInvocations) {
+      _mesa_error(ctx, GL_INVALID_VALUE,
+                  "glDispatchComputeGroupSizeARB(product of local_sizes "
+                  "exceeds MAX_COMPUTE_VARIABLE_GROUP_INVOCATIONS_ARB "
+                  "(%d > %d))", total_invocations,
+                  ctx->Const.MaxComputeVariableGroupInvocations);
+      return GL_FALSE;
+   }
+
    return GL_TRUE;
 }
 
@@ -1326,6 +1422,7 @@ valid_dispatch_indirect(struct gl_context *ctx,
                         GLsizei size, const char *name)
 {
    const uint64_t end = (uint64_t) indirect + size;
+   struct gl_shader_program *prog;
 
    if (!check_valid_to_compute(ctx, name))
       return GL_FALSE;
@@ -1371,6 +1468,18 @@ valid_dispatch_indirect(struct gl_context *ctx,
       return GL_FALSE;
    }
 
+   /* The ARB_compute_variable_group_size spec says:
+    *
+    * "An INVALID_OPERATION error is generated if the active program for the
+    *  compute shader stage has a variable work group size."
+    */
+   prog = ctx->_Shader->CurrentProgram[MESA_SHADER_COMPUTE];
+   if (prog->Comp.LocalSizeVariable) {
+      _mesa_error(ctx, GL_INVALID_OPERATION,
+                  "%s(variable work group size forbidden)", name);
+      return GL_FALSE;
+   }
+
    return GL_TRUE;
 }
 
diff --git a/src/mesa/main/api_validate.h b/src/mesa/main/api_validate.h
index 2eba834..e94f02e 100644
--- a/src/mesa/main/api_validate.h
+++ b/src/mesa/main/api_validate.h
@@ -132,5 +132,9 @@ extern GLboolean
 _mesa_validate_DispatchComputeIndirect(struct gl_context *ctx,
                                        GLintptr indirect);
 
+extern GLboolean
+_mesa_validate_DispatchComputeGroupSizeARB(struct gl_context *ctx,
+                                           const GLuint *num_groups,
+                                           const GLuint *group_size);
 
 #endif
diff --git a/src/mesa/main/compute.c b/src/mesa/main/compute.c
index b052bae..bb62539 100644
--- a/src/mesa/main/compute.c
+++ b/src/mesa/main/compute.c
@@ -66,5 +66,22 @@ _mesa_DispatchComputeGroupSizeARB(GLuint num_groups_x, GLuint num_groups_y,
                                   GLuint num_groups_z, GLuint group_size_x,
                                   GLuint group_size_y, GLuint group_size_z)
 {
+   GET_CURRENT_CONTEXT(ctx);
+   const GLuint num_groups[3] = { num_groups_x, num_groups_y, num_groups_z };
+   const GLuint group_size[3] = { group_size_x, group_size_y, group_size_z };
+
+   if (MESA_VERBOSE & VERBOSE_API)
+      _mesa_debug(ctx,
+                  "glDispatchComputeGroupSizeARB(%d, %d, %d, %d, %d, %d)\n",
+                  num_groups_x, num_groups_y, num_groups_z,
+                  group_size_x, group_size_y, group_size_z);
+
+   if (!_mesa_validate_DispatchComputeGroupSizeARB(ctx, num_groups,
+                                                   group_size))
+      return;
+
+   if (num_groups_x == 0u || num_groups_y == 0u || num_groups_z == 0u)
+       return;
 
+   ctx->Driver.DispatchComputeGroupSize(ctx, num_groups, group_size);
 }
diff --git a/src/mesa/main/context.c b/src/mesa/main/context.c
index 697b518..47fd4a0 100644
--- a/src/mesa/main/context.c
+++ b/src/mesa/main/context.c
@@ -721,6 +721,12 @@ _mesa_init_constants(struct gl_constants *consts, gl_api api)
    consts->MaxTessPatchComponents = MAX_TESS_PATCH_COMPONENTS;
    consts->MaxTessControlTotalOutputComponents = MAX_TESS_CONTROL_TOTAL_OUTPUT_COMPONENTS;
    consts->PrimitiveRestartForPatches = false;
+
+   /** GL_ARB_compute_variable_group_size */
+   consts->MaxComputeVariableGroupSize[0] = 512;
+   consts->MaxComputeVariableGroupSize[1] = 512;
+   consts->MaxComputeVariableGroupSize[2] = 64;
+   consts->MaxComputeVariableGroupInvocations = 512;
 }
 
 
diff --git a/src/mesa/main/dd.h b/src/mesa/main/dd.h
index 257dc10..7f53271 100644
--- a/src/mesa/main/dd.h
+++ b/src/mesa/main/dd.h
@@ -978,6 +978,15 @@ struct dd_function_table {
    /*@}*/
 
    /**
+    * \name GL_ARB_compute_variable_group_size interface
+    */
+   /*@{*/
+   void (*DispatchComputeGroupSize)(struct gl_context *ctx,
+                                    const GLuint *num_groups,
+                                    const GLuint *group_size);
+   /*@}*/
+
+   /**
     * Query information about memory. Device memory is e.g. VRAM. Staging
     * memory is e.g. GART. All sizes are in kilobytes.
     */
diff --git a/src/mesa/main/extensions_table.h b/src/mesa/main/extensions_table.h
index e7669bb..b6286fc 100644
--- a/src/mesa/main/extensions_table.h
+++ b/src/mesa/main/extensions_table.h
@@ -42,6 +42,7 @@ EXT(ARB_clip_control                        , ARB_clip_control
 EXT(ARB_color_buffer_float                  , ARB_color_buffer_float                 , GLL, GLC,  x ,  x , 2004)
 EXT(ARB_compressed_texture_pixel_storage    , dummy_true                             , GLL, GLC,  x ,  x , 2011)
 EXT(ARB_compute_shader                      , ARB_compute_shader                     , GLL, GLC,  x ,  x , 2012)
+EXT(ARB_compute_variable_group_size         , ARB_compute_variable_group_size        , GLL, GLC,  x ,  x , 2013)
 EXT(ARB_conditional_render_inverted         , ARB_conditional_render_inverted        , GLL, GLC,  x ,  x , 2014)
 EXT(ARB_conservative_depth                  , ARB_conservative_depth                 , GLL, GLC,  x ,  x , 2011)
 EXT(ARB_copy_buffer                         , dummy_true                             , GLL, GLC,  x ,  x , 2008)
diff --git a/src/mesa/main/get.c b/src/mesa/main/get.c
index 64a4b0e..bd85bef 100644
--- a/src/mesa/main/get.c
+++ b/src/mesa/main/get.c
@@ -490,6 +490,7 @@ EXTRA_EXT(ARB_cull_distance);
 EXTRA_EXT(EXT_window_rectangles);
 EXTRA_EXT(KHR_blend_equation_advanced_coherent);
 EXTRA_EXT(OES_primitive_bounding_box);
+EXTRA_EXT(ARB_compute_variable_group_size);
 
 static const int
 extra_ARB_color_buffer_float_or_glcore[] = {
@@ -2293,6 +2294,15 @@ find_value_indexed(const char *func, GLenum pname, GLuint index, union value *v)
          goto invalid_value;
       v->value_int = ctx->Const.MaxComputeWorkGroupSize[index];
       return TYPE_INT;
+
+   /* ARB_compute_variable_group_size */
+   case GL_MAX_COMPUTE_VARIABLE_GROUP_SIZE_ARB:
+      if (!ctx->Extensions.ARB_compute_variable_group_size)
+         goto invalid_enum;
+      if (index >= 3)
+         goto invalid_value;
+      v->value_int = ctx->Const.MaxComputeVariableGroupSize[index];
+      return TYPE_INT;
    }
 
  invalid_enum:
diff --git a/src/mesa/main/get_hash_params.py b/src/mesa/main/get_hash_params.py
index 7520a39..6849b5b 100644
--- a/src/mesa/main/get_hash_params.py
+++ b/src/mesa/main/get_hash_params.py
@@ -942,6 +942,9 @@ descriptor=[
 # GL_ARB_cull_distance
   [ "MAX_CULL_DISTANCES", "CONTEXT_INT(Const.MaxClipPlanes), extra_ARB_cull_distance" ],
   [ "MAX_COMBINED_CLIP_AND_CULL_DISTANCES", "CONTEXT_INT(Const.MaxClipPlanes), extra_ARB_cull_distance" ],
+
+# GL_ARB_compute_variable_group_size
+  [ "MAX_COMPUTE_VARIABLE_GROUP_INVOCATIONS_ARB", "CONTEXT_INT(Const.MaxComputeVariableGroupInvocations), extra_ARB_compute_variable_group_size" ],
 ]},
 
 # Enums restricted to OpenGL Core profile
diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h
index d494872..ab9839c 100644
--- a/src/mesa/main/mtypes.h
+++ b/src/mesa/main/mtypes.h
@@ -2078,6 +2078,11 @@ struct gl_compute_program
     * Size of shared variables accessed by the compute shader.
     */
    unsigned SharedSize;
+
+   /**
+    * Whether a variable work group size has been specified.
+    */
+   bool LocalSizeVariable;
 };
 
 
@@ -2340,7 +2345,8 @@ struct gl_shader_info
    GLbitfield BlendSupport;
 
    /**
-    * Compute shader state from ARB_compute_shader layout qualifiers.
+    * Compute shader state from ARB_compute_shader and
+    * ARB_compute_variable_group_size layout qualifiers.
     */
    struct {
       /**
@@ -2348,6 +2354,12 @@ struct gl_shader_info
        * it's not set in this shader.
        */
       unsigned LocalSize[3];
+
+      /**
+       * Whether a variable work group size has been specified as defined by
+       * ARB_compute_variable_group_size.
+       */
+      bool LocalSizeVariable;
    } Comp;
 };
 
@@ -2826,6 +2838,11 @@ struct gl_shader_program
        * Size of shared variables accessed by the compute shader.
        */
       unsigned SharedSize;
+
+      /**
+       * Whether a variable work group size has been specified.
+       */
+      bool LocalSizeVariable;
    } Comp;
 
    /* post-link info: */
@@ -3783,6 +3800,10 @@ struct gl_constants
    GLuint MaxComputeWorkGroupInvocations;
    GLuint MaxComputeSharedMemorySize;
 
+   /** GL_ARB_compute_variable_group_size */
+   GLuint MaxComputeVariableGroupSize[3]; /* Array of x, y, z dimensions */
+   GLuint MaxComputeVariableGroupInvocations;
+
    /** GL_ARB_gpu_shader5 */
    GLfloat MinFragmentInterpolationOffset;
    GLfloat MaxFragmentInterpolationOffset;
@@ -3834,6 +3855,7 @@ struct gl_extensions
    GLboolean ARB_clip_control;
    GLboolean ARB_color_buffer_float;
    GLboolean ARB_compute_shader;
+   GLboolean ARB_compute_variable_group_size;
    GLboolean ARB_conditional_render_inverted;
    GLboolean ARB_conservative_depth;
    GLboolean ARB_copy_image;
diff --git a/src/mesa/main/shaderapi.c b/src/mesa/main/shaderapi.c
index 1af1c3f..c40bb2d 100644
--- a/src/mesa/main/shaderapi.c
+++ b/src/mesa/main/shaderapi.c
@@ -2212,6 +2212,7 @@ _mesa_copy_linked_program_data(gl_shader_stage type,
       for (i = 0; i < 3; i++)
          dst_cp->LocalSize[i] = src->Comp.LocalSize[i];
       dst_cp->SharedSize = src->Comp.SharedSize;
+      dst_cp->LocalSizeVariable = src->Comp.LocalSizeVariable;
       break;
    }
    default:
diff --git a/src/mesa/main/shaderobj.c b/src/mesa/main/shaderobj.c
index 350b677..136ac7b 100644
--- a/src/mesa/main/shaderobj.c
+++ b/src/mesa/main/shaderobj.c
@@ -262,6 +262,8 @@ init_shader_program(struct gl_shader_program *prog)
    prog->Geom.UsesEndPrimitive = false;
    prog->Geom.UsesStreams = false;
 
+   prog->Comp.LocalSizeVariable = false;
+
    prog->TransformFeedback.BufferMode = GL_INTERLEAVED_ATTRIBS;
 
    exec_list_make_empty(&prog->EmptyUniformLocations);