glsl/link,i965: Make ImageAccess four-state

The GLSL spec allows you to set both the "readonly" and "writeonly"
qualifiers on images to indicate that it can only be used with
imageSize.  However, we had no way of representing this int he linked
shader and flagged it as GL_READ_ONLY.  This is good from a "does it use
this buffer?" perspective but not from a format and access lowering
perspective.  By using GL_NONE for if "readonly" and "writeonly" are
both set, we can detect this case in the driver and handle it correctly.

Nothing currently relies on the type of surface in the "readonly" +
"writeonly" case but that's about to change.  i965 is the only drier
which uses the ImageAccess field and gl_bindless_image::access is
currently unused.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>

diff --git a/src/compiler/glsl/gl_nir_link_uniforms.c b/src/compiler/glsl/gl_nir_link_uniforms.c
index 1573e30c41e7f7a9f7d4aa26e8e1d065081eef74..159dfeca59ffa020f1d305822ee57708ffbc788f 100644 (file)
--- a/src/compiler/glsl/gl_nir_link_uniforms.c
+++ b/src/compiler/glsl/gl_nir_link_uniforms.c
@@ -425,9 +425,11 @@ nir_link_uniform(struct gl_context *ctx,
 
          /* Set image access qualifiers */
          const GLenum access =
-            (state->current_var->data.image.read_only ? GL_READ_ONLY :
-             state->current_var->data.image.write_only ? GL_WRITE_ONLY :
-             GL_READ_WRITE);
+            state->current_var->data.image.read_only ?
+            (state->current_var->data.image.write_only ? GL_NONE :
+                                                         GL_READ_ONLY) :
+            (state->current_var->data.image.write_only ? GL_WRITE_ONLY :
+                                                         GL_READ_WRITE);
          for (unsigned i = image_index;
               i < MIN2(state->next_image_index, MAX_IMAGE_UNIFORMS);
               i++) {

diff --git a/src/compiler/glsl/link_uniforms.cpp b/src/compiler/glsl/link_uniforms.cpp
index 434ecefb2893eaec7b170b939e22334ea44d930a..63e688b19a7055d6bcd3da1feabde369c9e68afa 100644 (file)
--- a/src/compiler/glsl/link_uniforms.cpp
+++ b/src/compiler/glsl/link_uniforms.cpp
@@ -690,9 +690,11 @@ private:
 
          /* Set image access qualifiers */
          const GLenum access =
-            (current_var->data.memory_read_only ? GL_READ_ONLY :
-             current_var->data.memory_write_only ? GL_WRITE_ONLY :
-                GL_READ_WRITE);
+            current_var->data.memory_read_only ?
+            (current_var->data.memory_write_only ? GL_NONE :
+                                                   GL_READ_ONLY) :
+            (current_var->data.memory_write_only ? GL_WRITE_ONLY :
+                                                   GL_READ_WRITE);
 
          if (current_var->data.bindless) {
             if (!set_opaque_indices(base_type, uniform, name,

diff --git a/src/mesa/drivers/dri/i965/brw_wm_surface_state.c b/src/mesa/drivers/dri/i965/brw_wm_surface_state.c
index 2aef0ef59f7949181c3269e025b24528bdcbcc09..35bb49f30f29d3e7154b5b3bfcc232e1d235b87c 100644 (file)
--- a/src/mesa/drivers/dri/i965/brw_wm_surface_state.c
+++ b/src/mesa/drivers/dri/i965/brw_wm_surface_state.c
@@ -1455,7 +1455,7 @@ get_image_format(struct brw_context *brw, mesa_format format, GLenum access)
 {
    const struct gen_device_info *devinfo = &brw->screen->devinfo;
    enum isl_format hw_format = brw_isl_format_for_mesa_format(format);
-   if (access == GL_WRITE_ONLY) {
+   if (access == GL_WRITE_ONLY || access == GL_NONE) {
       return hw_format;
    } else if (isl_has_matching_typed_storage_image_format(devinfo, hw_format)) {
       /* Typed surface reads support a very limited subset of the shader
@@ -1523,6 +1523,7 @@ update_image_surface(struct brw_context *brw,
    if (_mesa_is_image_unit_valid(&brw->ctx, u)) {
       struct gl_texture_object *obj = u->TexObj;
       const unsigned format = get_image_format(brw, u->_ActualFormat, access);
+      const bool written = (access != GL_READ_ONLY && access != GL_NONE);
 
       if (obj->Target == GL_TEXTURE_BUFFER) {
          const unsigned texel_size = (format == ISL_FORMAT_RAW ? 1 :
@@ -1530,13 +1531,12 @@ update_image_surface(struct brw_context *brw,
          const unsigned buffer_size = buffer_texture_range_size(brw, obj);
          struct brw_bo *const bo = !obj->BufferObject ? NULL :
             intel_bufferobj_buffer(brw, intel_buffer_object(obj->BufferObject),
-                                   obj->BufferOffset, buffer_size,
-                                   access != GL_READ_ONLY);
+                                   obj->BufferOffset, buffer_size, written);
 
          brw_emit_buffer_surface_state(
             brw, surf_offset, bo, obj->BufferOffset,
             format, buffer_size, texel_size,
-            access != GL_READ_ONLY ? RELOC_WRITE : 0);
+            written ? RELOC_WRITE : 0);
 
          update_buffer_image_param(brw, u, surface_idx, param);
 
@@ -1560,7 +1560,7 @@ update_image_surface(struct brw_context *brw,
             brw_emit_buffer_surface_state(
                brw, surf_offset, mt->bo, mt->offset,
                format, mt->bo->size - mt->offset, 1 /* pitch */,
-               access != GL_READ_ONLY ? RELOC_WRITE : 0);
+               written ? RELOC_WRITE : 0);
 
          } else {
             const int surf_index = surf_offset - &brw->wm.base.surf_offset[0];
@@ -1571,7 +1571,7 @@ update_image_surface(struct brw_context *brw,
             brw_emit_surface_state(brw, mt, mt->target, view,
                                    ISL_AUX_USAGE_NONE,
                                    surf_offset, surf_index,
-                                   access == GL_READ_ONLY ? 0 : RELOC_WRITE);
+                                   written ? RELOC_WRITE : 0);
          }
 
          isl_surf_fill_image_param(&brw->isl_dev, param, &mt->surf, &view);

diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h
index 5ce0b4b584719abda0aa88fb5d52bbfb07872f1c..718293be116bfe05f86a8b011a04f535290a5203 100644 (file)
--- a/src/mesa/main/mtypes.h
+++ b/src/mesa/main/mtypes.h
@@ -2014,7 +2014,9 @@ struct gl_bindless_image
    /** Whether this bindless image is bound to a unit. */
    GLboolean bound;
 
-   /** Access qualifier (GL_READ_WRITE, GL_READ_ONLY, GL_WRITE_ONLY) */
+   /** Access qualifier (GL_READ_WRITE, GL_READ_ONLY, GL_WRITE_ONLY, or
+    * GL_NONE to indicate both read-only and write-only)
+    */
    GLenum16 access;
 
    /** Pointer to the base of the data. */
@@ -2131,8 +2133,9 @@ struct gl_program
 
          /**
           * Access qualifier specified in the shader for each image uniform
-          * index.  Either \c GL_READ_ONLY, \c GL_WRITE_ONLY or \c
-          * GL_READ_WRITE.
+          * index.  Either \c GL_READ_ONLY, \c GL_WRITE_ONLY, \c
+          * GL_READ_WRITE, or \c GL_NONE to indicate both read-only and
+          * write-only.
           *
           * It may be different, though only more strict than the value of
           * \c gl_image_unit::Access for the corresponding image unit.