gallium: add INVOCATIONID semantic

Signed-off-by: Ilia Mirkin <imirkin@alum.mit.edu>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>

src/gallium/auxiliary/tgsi/tgsi_strings.c

@@ -84,7 +84,8 @@ const char *tgsi_semantic_names[TGSI_SEMANTIC_COUNT] =
    "CULLDIST",
    "SAMPLEID",
    "SAMPLEPOS",
-   "SAMPLEMASK"
+   "SAMPLEMASK",
+   "INVOCATIONID",
 };
 
 const char *tgsi_texture_names[TGSI_TEXTURE_COUNT] =

src/gallium/docs/source/tgsi.rst

@@ -2641,6 +2641,12 @@ For fragment shaders, this semantic label indicates that an output contains
 the sample mask used to disable further sample processing
 (i.e. gl_SampleMask). Only the X value is used, up to 32x MS.
 
+TGSI_SEMANTIC_INVOCATIONID
+""""""""""""""""""""""""""
+
+For geometry shaders, this semantic label indicates that a system value
+contains the current invocation id (i.e. gl_InvocationID). Only the X value is
+used.
 
 Declaration Interpolate
 ^^^^^^^^^^^^^^^^^^^^^^^

src/gallium/include/pipe/p_shader_tokens.h

@@ -170,7 +170,8 @@ struct tgsi_declaration_interp
 #define TGSI_SEMANTIC_SAMPLEID   24
 #define TGSI_SEMANTIC_SAMPLEPOS  25
 #define TGSI_SEMANTIC_SAMPLEMASK 26
-#define TGSI_SEMANTIC_COUNT      27 /**< number of semantic values */
+#define TGSI_SEMANTIC_INVOCATIONID 27
+#define TGSI_SEMANTIC_COUNT      28 /**< number of semantic values */
 
 struct tgsi_declaration_semantic
 {