symbol.h

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/*
 * Copyright (c) 2023 Intel Corporation
 *
 * SPDX-License-Identifier: Apache-2.0
 */
 
#ifndef ZEPHYR_LLEXT_SYMBOL_H
#define ZEPHYR_LLEXT_SYMBOL_H
 
#include <zephyr/sys/iterable_sections.h>
#include <zephyr/sys/util_macro.h>
#include <zephyr/toolchain.h>
#include <stddef.h>
#include <stdint.h>
 
#ifdef __cplusplus
extern "C" {
#endif


struct llext_const_symbol {
        union {
                const char *const name;

                const uintptr_t slid;
        };

        const void *const addr;
};
BUILD_ASSERT(sizeof(struct llext_const_symbol) == 2 * sizeof(uintptr_t));

struct llext_symbol {
        const char *name;

        void *addr;
};
 

struct llext_symtable {
        size_t sym_cnt;

        struct llext_symbol *syms;
};


struct z_llext_discarded_const_symbol {
        const char *const name;

        const char *const group;
};
 
#define Z_LLEXT_DISCARD_STRTAB Z_GENERIC_SECTION(llext_discarded_exports_strtab)
 
#define Z_MARKUP_NOT_EXPORTED_SYMBOL(grp, sym_ident, sym_name)          \
        static const char Z_LLEXT_DISCARD_STRTAB __used                         \
                __llext_sym_name_ ## sym_name[] = STRINGIFY(sym_name);          \
        static const char Z_LLEXT_DISCARD_STRTAB __used                         \
                __llext_sym_group_ ## sym_name[] = STRINGIFY(grp);              \
        static const struct z_llext_discarded_const_symbol                      \
                Z_GENERIC_SECTION(llext_discarded_exports_table) __used         \
                __llext_sym_discarded_ ## sym_name = {                          \
                        .name = __llext_sym_name_ ## sym_name,                  \
                        .group = __llext_sym_group_ ## sym_name,                \
        };

#ifdef LL_EXTENSION_BUILD
/* Extension build: add exported symbols to llext table */
#define Z_LL_EXTENSION_SYMBOL_NAMED(sym_ident, sym_name)                        \
        static const struct llext_const_symbol                                  \
                        Z_GENERIC_SECTION(.exported_sym) __used                 \
                        __llext_sym_ ## sym_name = {                            \
                .name = STRINGIFY(sym_name), .addr = (const void *)&sym_ident,  \
        }
#else
/* No-op when not building an extension */
#define Z_LL_EXTENSION_SYMBOL_NAMED(sym_ident, sym_name)
#endif

#define LL_EXTENSION_SYMBOL_NAMED(sym_ident, sym_name)                          \
        Z_LL_EXTENSION_SYMBOL_NAMED(sym_ident, sym_name)

#define LL_EXTENSION_SYMBOL(x) Z_LL_EXTENSION_SYMBOL_NAMED(x, x)

#if defined(LL_EXTENSION_BUILD)
/* Extension build: EXPORT_SYMBOL maps to LL_EXTENSION_SYMBOL */
#define Z_EXPORT_SYMBOL_NAMED(sym_ident, sym_name)                              \
        Z_LL_EXTENSION_SYMBOL_NAMED(sym_ident, sym_name)
#elif defined(CONFIG_LLEXT_EXPORT_BUILTINS_BY_SLID)
/* SLID-enabled LLEXT application: export symbols, names in separate section */
#define Z_EXPORT_SYMBOL_NAMED(sym_ident, sym_name)                              \
        static const char Z_GENERIC_SECTION(llext_exports_strtab) __used        \
                __llext_sym_name_ ## sym_name[] = STRINGIFY(sym_name);          \
        static const STRUCT_SECTION_ITERABLE(llext_const_symbol,                \
                                             __llext_sym_ ## sym_name) = {      \
                .name = __llext_sym_name_ ## sym_name,                          \
                .addr = (const void *)&sym_ident,                               \
        }
#elif defined(CONFIG_LLEXT)
/* LLEXT application: export symbols */
#define Z_EXPORT_SYMBOL_NAMED(sym_ident, sym_name)                              \
        static const STRUCT_SECTION_ITERABLE(llext_const_symbol,                \
                                             __llext_sym_ ## sym_name) = {      \
                .name = STRINGIFY(sym_name), .addr = (const void *)&sym_ident,  \
        }
#else
/* No extension support in this build */
#define Z_EXPORT_SYMBOL_NAMED(sym_ident, sym_name)
#endif
 
#if defined(LL_EXTENSION_BUILD)
/* Extension build: No Kconfig conditionals */
#define Z_EXPORT_SYMBOL_NAMED_IN_GROUP(group, sym_ident, sym_name)              \
        Z_EXPORT_SYMBOL_NAMED(sym_ident, sym_name)
#else
/* LLEXT application: Export if relevant group is enabled */
#define Z_EXPORT_SYMBOL_NAMED_IN_GROUP(group, sym_ident, sym_name)              \
        COND_CODE_1(CONFIG_LLEXT_EXPORT_SYMBOL_GROUP_ ## group,                 \
                (Z_EXPORT_SYMBOL_NAMED(sym_ident, sym_name)),                   \
                (Z_MARKUP_NOT_EXPORTED_SYMBOL(group, sym_ident, sym_name)))
#endif /* defined(LL_EXTENSION_BUILD) */

#define EXPORT_SYMBOL_NAMED(sym_ident, sym_name)                                \
        Z_EXPORT_SYMBOL_NAMED_IN_GROUP(UNASSIGNED, sym_ident, sym_name)

#define EXPORT_SYMBOL(x) EXPORT_SYMBOL_NAMED(x, x)

#define EXPORT_GROUP_SYMBOL_NAMED(group, sym_ident, sym_name)                   \
        Z_EXPORT_SYMBOL_NAMED_IN_GROUP(group, sym_ident, sym_name)

#define EXPORT_GROUP_SYMBOL(group, sym_ident) \
        EXPORT_GROUP_SYMBOL_NAMED(group, sym_ident, sym_ident)

 
#ifdef __cplusplus
}
#endif
 
 
#endif /* ZEPHYR_LLEXT_SYMBOL_H */