pco/usclib: add some preprocessor helper macros

Signed-off-by: Simon Perretta <simon.perretta@imgtec.com>
Acked-by: Erik Faye-Lund <erik.faye-lund@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/37439>

src/imagination/pco/usclib/libcl.h

@@ -9,6 +9,7 @@
 #include "compiler/libcl/libcl.h"
 #include "compiler/shader_enums.h"
 #include "pco/pco_common.h"
+#include "pp_macros.h"
 
 void nir_mutex_pco(enum pco_mutex_id mutex_id, enum pco_mutex_op mutex_op);
 uint32_t nir_load_instance_num_pco(void);

src/imagination/pco/usclib/pp_macros.h

@@ -0,0 +1,89 @@
+/*
+ * Copyright © 2025 Imagination Technologies Ltd.
+ * SPDX-License-Identifier: MIT
+ */
+
+#ifndef PCO_PP_MACROS_H
+#define PCO_PP_MACROS_H
+
+#define _NUM_ARGS(_0,  \
+                  _1,  \
+                  _2,  \
+                  _3,  \
+                  _4,  \
+                  _5,  \
+                  _6,  \
+                  _7,  \
+                  _8,  \
+                  _9,  \
+                  _10, \
+                  _11, \
+                  _12, \
+                  _13, \
+                  _14, \
+                  _15, \
+                  _16, \
+                  N,   \
+                  ...) \
+   N
+
+/* Returns the numbers of arguments passed to the macro. */
+#define NUM_ARGS(...)       \
+   _NUM_ARGS(_,             \
+             ##__VA_ARGS__, \
+             16,            \
+             15,            \
+             14,            \
+             13,            \
+             12,            \
+             11,            \
+             10,            \
+             9,             \
+             8,             \
+             7,             \
+             6,             \
+             5,             \
+             4,             \
+             3,             \
+             2,             \
+             1,             \
+             0)
+
+/* Returns the numbers of arguments passed to the macro + 2. */
+#define NUM_ARGS_PLUS_2(...) \
+   _NUM_ARGS(_,              \
+             ##__VA_ARGS__,  \
+             18,             \
+             17,             \
+             16,             \
+             15,             \
+             14,             \
+             13,             \
+             12,             \
+             11,             \
+             10,             \
+             9,              \
+             8,              \
+             7,              \
+             6,              \
+             5,              \
+             4,              \
+             3,              \
+             2)
+
+#define _CAT2(a, b) a##b
+
+/* Concatenates two tokens. */
+#define CAT2(a, b) _CAT2(a, b)
+
+#define _CAT3(a, b, c) a##b##c
+
+/* Concatenates three tokens. */
+#define CAT3(a, b, c) _CAT3(a, b, c)
+
+/* Constructs a function name from its base name, separator, and the number of
+ * args passed to it.
+ */
+#define SELECT_NAME(f, sep, ...) CAT3(f, sep, NUM_ARGS(__VA_ARGS__))
+
+#endif /* ifndef PCO_PP_MACROS_H */