spirv: Add support for SPV_KHR_multiview

Reviewed-by: Iago Toral Quiroga <itoral@igalia.com>
Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>

src/compiler/spirv/nir_spirv.h

@@ -50,6 +50,7 @@ struct nir_spirv_supported_extensions {
    bool image_read_without_format;
    bool image_write_without_format;
    bool int64;
+   bool multiview;
 };
 
 nir_function *spirv_to_nir(const uint32_t *words, size_t word_count,

src/compiler/spirv/spirv_to_nir.c

@@ -2730,6 +2730,10 @@ vtn_handle_preamble_instruction(struct vtn_builder *b, SpvOp opcode,
          spv_check_supported(image_write_without_format, cap);
          break;
 
+      case SpvCapabilityMultiView:
+         spv_check_supported(multiview, cap);
+         break;
+
       default:
          unreachable("Unhandled capability");
       }

src/compiler/spirv/vtn_variables.c

@@ -1036,6 +1036,10 @@ vtn_get_builtin_location(struct vtn_builder *b,
       *location = SYSTEM_VALUE_DRAW_ID;
       set_mode_system_value(mode);
       break;
+   case SpvBuiltInViewIndex:
+      *location = SYSTEM_VALUE_VIEW_INDEX;
+      set_mode_system_value(mode);
+      break;
    case SpvBuiltInHelperInvocation:
    default:
       unreachable("unsupported builtin");