glsl: add subpass image type (v2)

SPIR-V/Vulkan have a special image type for input attachments
called the subpass type. It has different characteristics than
other images types.

The main one being it can only be an input image to fragment
shaders and loads from it are relative to the frag coord.

This adds support for it to the GLSL types. Unfortunately
we've run out of space in the sampler dim in types, so we
need to use another bit.

v2: Fixup subpass input name (Jason)

Reviewed-by: Jason Ekstrand <[email protected]>
Signed-off-by: Dave Airlie <[email protected]>

4 files changed, 18 insertions, 2 deletions

diff --git a/src/compiler/builtin_type_macros.h b/src/compiler/builtin_type_macros.h
index da3f19e7ab2..3db3b76bea3 100644
--- a/src/compiler/builtin_type_macros.h
+++ b/src/compiler/builtin_type_macros.h
@@ -159,6 +159,8 @@ DECL_TYPE(uimageCubeArray, GL_UNSIGNED_INT_IMAGE_CUBE_MAP_ARRAY,       GLSL_TYPE
 DECL_TYPE(uimage2DMS,      GL_UNSIGNED_INT_IMAGE_2D_MULTISAMPLE,       GLSL_TYPE_IMAGE, GLSL_SAMPLER_DIM_MS,     0, 0, GLSL_TYPE_UINT)
 DECL_TYPE(uimage2DMSArray, GL_UNSIGNED_INT_IMAGE_2D_MULTISAMPLE_ARRAY, GLSL_TYPE_IMAGE, GLSL_SAMPLER_DIM_MS,     0, 1, GLSL_TYPE_UINT)
 
+DECL_TYPE(subpassInput,    0,                                          GLSL_TYPE_IMAGE, GLSL_SAMPLER_DIM_SUBPASS,0, 0, GLSL_TYPE_FLOAT)
+
 DECL_TYPE(atomic_uint, GL_UNSIGNED_INT_ATOMIC_COUNTER, GLSL_TYPE_ATOMIC_UINT, 1, 1)
 
 STRUCT_TYPE(gl_DepthRangeParameters)
diff --git a/src/compiler/glsl_types.cpp b/src/compiler/glsl_types.cpp
index 641644d2d95..73e3abd329d 100644
--- a/src/compiler/glsl_types.cpp
+++ b/src/compiler/glsl_types.cpp
@@ -674,6 +674,8 @@ glsl_type::get_sampler_instance(enum glsl_sampler_dim dim,
             return error_type;
          else
             return samplerExternalOES_type;
+      case GLSL_SAMPLER_DIM_SUBPASS:
+         return error_type;
       }
    case GLSL_TYPE_INT:
       if (shadow)
@@ -701,6 +703,8 @@ glsl_type::get_sampler_instance(enum glsl_sampler_dim dim,
          return (array ? isampler2DMSArray_type : isampler2DMS_type);
       case GLSL_SAMPLER_DIM_EXTERNAL:
          return error_type;
+      case GLSL_SAMPLER_DIM_SUBPASS:
+         return error_type;
       }
    case GLSL_TYPE_UINT:
       if (shadow)
@@ -728,6 +732,8 @@ glsl_type::get_sampler_instance(enum glsl_sampler_dim dim,
          return (array ? usampler2DMSArray_type : usampler2DMS_type);
       case GLSL_SAMPLER_DIM_EXTERNAL:
          return error_type;
+      case GLSL_SAMPLER_DIM_SUBPASS:
+         return error_type;
       }
    default:
       return error_type;
@@ -740,6 +746,8 @@ const glsl_type *
 glsl_type::get_image_instance(enum glsl_sampler_dim dim,
                               bool array, glsl_base_type type)
 {
+   if (dim == GLSL_SAMPLER_DIM_SUBPASS)
+      return subpassInput_type;
    switch (type) {
    case GLSL_TYPE_FLOAT:
       switch (dim) {
@@ -764,6 +772,7 @@ glsl_type::get_image_instance(enum glsl_sampler_dim dim,
       case GLSL_SAMPLER_DIM_MS:
          return (array ? image2DMSArray_type : image2DMS_type);
       case GLSL_SAMPLER_DIM_EXTERNAL:
+      case GLSL_SAMPLER_DIM_SUBPASS:
          return error_type;
       }
    case GLSL_TYPE_INT:
@@ -789,6 +798,7 @@ glsl_type::get_image_instance(enum glsl_sampler_dim dim,
       case GLSL_SAMPLER_DIM_MS:
          return (array ? iimage2DMSArray_type : iimage2DMS_type);
       case GLSL_SAMPLER_DIM_EXTERNAL:
+      case GLSL_SAMPLER_DIM_SUBPASS:
          return error_type;
       }
    case GLSL_TYPE_UINT:
@@ -814,6 +824,7 @@ glsl_type::get_image_instance(enum glsl_sampler_dim dim,
       case GLSL_SAMPLER_DIM_MS:
          return (array ? uimage2DMSArray_type : uimage2DMS_type);
       case GLSL_SAMPLER_DIM_EXTERNAL:
+      case GLSL_SAMPLER_DIM_SUBPASS:
          return error_type;
       }
    default:
@@ -1975,6 +1986,7 @@ glsl_type::coordinate_components() const
    case GLSL_SAMPLER_DIM_RECT:
    case GLSL_SAMPLER_DIM_MS:
    case GLSL_SAMPLER_DIM_EXTERNAL:
+   case GLSL_SAMPLER_DIM_SUBPASS:
       size = 2;
       break;
    case GLSL_SAMPLER_DIM_3D:
diff --git a/src/compiler/glsl_types.h b/src/compiler/glsl_types.h
index 7c4827d8f83..b1e2f7a0181 100644
--- a/src/compiler/glsl_types.h
+++ b/src/compiler/glsl_types.h
@@ -80,7 +80,8 @@ enum glsl_sampler_dim {
    GLSL_SAMPLER_DIM_RECT,
    GLSL_SAMPLER_DIM_BUF,
    GLSL_SAMPLER_DIM_EXTERNAL,
-   GLSL_SAMPLER_DIM_MS
+   GLSL_SAMPLER_DIM_MS,
+   GLSL_SAMPLER_DIM_SUBPASS, /* for vulkan input attachments */
 };
 
 enum glsl_interface_packing {
@@ -127,7 +128,7 @@ struct glsl_type {
    GLenum gl_type;
    glsl_base_type base_type;
 
-   unsigned sampler_dimensionality:3; /**< \see glsl_sampler_dim */
+   unsigned sampler_dimensionality:4; /**< \see glsl_sampler_dim */
    unsigned sampler_shadow:1;
    unsigned sampler_array:1;
    unsigned sampled_type:2;    /**< Type of data returned using this
diff --git a/src/compiler/nir/nir.h b/src/compiler/nir/nir.h
index 6f0597200e9..aac247c79c0 100644
--- a/src/compiler/nir/nir.h
+++ b/src/compiler/nir/nir.h
@@ -1198,6 +1198,7 @@ nir_tex_instr_dest_size(nir_tex_instr *instr)
          case GLSL_SAMPLER_DIM_MS:
          case GLSL_SAMPLER_DIM_RECT:
          case GLSL_SAMPLER_DIM_EXTERNAL:
+         case GLSL_SAMPLER_DIM_SUBPASS:
             ret = 2;
             break;
          case GLSL_SAMPLER_DIM_3D: