| /* |
| * Copyright (c) 2010, 2012, 2014 Wind River Systems, Inc. |
| * |
| * SPDX-License-Identifier: Apache-2.0 |
| */ |
| |
| /** |
| * @file |
| * @brief Macros to generate structure member offset definitions |
| * |
| * This header contains macros to allow a kernel implementation to generate |
| * absolute symbols whose values represents the member offsets for various |
| * kernel structures. These absolute symbols are typically utilized by |
| * assembly source files rather than hardcoding the values in some local header |
| * file. |
| * |
| * WARNING: Absolute symbols can potentially be utilized by external tools -- |
| * for example, to locate a specific field within a data structure. |
| * Consequently, changes made to such symbols may require modifications to the |
| * associated tool(s). Typically, relocating a member of a structure merely |
| * requires that a tool be rebuilt; however, moving a member to another |
| * structure (or to a new sub-structure within an existing structure) may |
| * require that the tool itself be modified. Likewise, deleting, renaming, or |
| * changing the meaning of an absolute symbol may require modifications to a |
| * tool. |
| * |
| * The macro "GEN_OFFSET_SYM(structure, member)" is used to generate a single |
| * absolute symbol. The absolute symbol will appear in the object module |
| * generated from the source file that utilizes the GEN_OFFSET_SYM() macro. |
| * Absolute symbols representing a structure member offset have the following |
| * form: |
| * |
| * __<structure>_<member>_OFFSET |
| * |
| * This header also defines the GEN_ABSOLUTE_SYM macro to simply define an |
| * absolute symbol, irrespective of whether the value represents a structure |
| * or offset. |
| * |
| * The following sample file illustrates the usage of the macros available |
| * in this file: |
| * |
| * <START of sample source file: offsets.c> |
| * |
| * #include <gen_offset.h> |
| * /@ include struct definitions for which offsets symbols are to be |
| * generated @/ |
| * |
| * #include <kernel_structs.h> |
| * GEN_ABS_SYM_BEGIN (_OffsetAbsSyms) /@ the name parameter is arbitrary @/ |
| * /@ _kernel_t structure member offsets @/ |
| * |
| * GEN_OFFSET_SYM (_kernel_t, nested); |
| * GEN_OFFSET_SYM (_kernel_t, irq_stack); |
| * GEN_OFFSET_SYM (_kernel_t, current); |
| * GEN_OFFSET_SYM (_kernel_t, idle); |
| * |
| * GEN_ABSOLUTE_SYM (___kernel_t_SIZEOF, sizeof(_kernel_t)); |
| * |
| * GEN_ABS_SYM_END |
| * <END of sample source file: offsets.c> |
| * |
| * Compiling the sample offsets.c results in the following symbols in offsets.o: |
| * |
| * $ nm offsets.o |
| * 00000000 A ___kernel_t_nested_OFFSET |
| * 00000004 A ___kernel_t_irq_stack_OFFSET |
| * 00000008 A ___kernel_t_current_OFFSET |
| * 0000000c A ___kernel_t_idle_OFFSET |
| */ |
| |
| #ifndef _GEN_OFFSET_H |
| #define _GEN_OFFSET_H |
| |
| #include <toolchain.h> |
| #include <stddef.h> |
| |
| /* definition of the GEN_OFFSET_SYM() macros is toolchain independent */ |
| |
| #define GEN_OFFSET_SYM(S, M) \ |
| GEN_ABSOLUTE_SYM(__##S##_##M##_##OFFSET, offsetof(S, M)) |
| |
| #endif /* _GEN_OFFSET_H */ |
