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Diffstat (limited to 'cpukit/include/rtems/rtl/rtl-unresolved.h')
| -rw-r--r-- | cpukit/include/rtems/rtl/rtl-unresolved.h | 212 |
1 files changed, 212 insertions, 0 deletions
diff --git a/cpukit/include/rtems/rtl/rtl-unresolved.h b/cpukit/include/rtems/rtl/rtl-unresolved.h new file mode 100644 index 0000000000..bd4ce2a215 --- /dev/null +++ b/cpukit/include/rtems/rtl/rtl-unresolved.h @@ -0,0 +1,212 @@ +/* + * COPYRIGHT (c) 2012 Chris Johns <chrisj@rtems.org> + * + * The license and distribution terms for this file may be + * found in the file LICENSE in this distribution or at + * http://www.rtems.org/license/LICENSE. + */ +/** + * @file + * + * @ingroup rtems_rtl + * + * @brief RTEMS Run-Time Linker Object File Unresolved Relocations Table. + * + * The unresolved relocation table holds relocations in a loaded object file + * which reference unresolved external symbols. The support is needed to allow + * dependent object files to load. In the case of dependent object files one + * will have unresolved externals until the dependent object file is also + * loaded. There is no load order that resolves this. + * + * The unresolved relocation table is a single table used by all object files + * with unresolved symbols. It made of blocks linked together where blocks are + * allocated as requiered. The table is always maintained compacted. That is as + * relocations are resolved and removed the table is compacted. The only + * pointer in the table is the object file poniter. This is used to identify + * which object the relocation belongs to. There are no linking or back + * pointers in the unresolved relocations table. The table is scanned for each + * object file's relocations. This is not fast but the table should be small + * and if it happens to grow large you have other more pressing issues to + * resolve in your application. + * + * The table holds two (2) types of records: + * + * # Symbol name strings. + * # Relocations. + * + * The symbol name a relocation references is held in a specific symbol name + * string record in the table the relocation record references. The record + * counts the number of references and the string is removed from the table + * when the reference count reaches 0. There can be many relocations + * referencing the symbol. The strings are referenced by a single 16bit + * unsigned integer which is the count of the string in the table. + * + * The section the relocation is for in the object is the section number. The + * relocation data is series of machine word sized fields: + * + * # Offset in the section. + * # Relocation info (format specific) + * # Additional format specific data. + */ + +#if !defined (_RTEMS_RTL_UNRESOLVED_H_) +#define _RTEMS_RTL_UNRESOLVED_H_ + +#include <rtems.h> +#include "rtl-obj-fwd.h" + +#ifdef __cplusplus +extern "C" { +#endif /* __cplusplus */ + +/** + * Hack to work around machine size. This needs to be cleaned up + * to better support 64bit targets. + */ +typedef uint32_t rtems_rtl_word_t; + +/** + * The types of records in the blocks. + */ +typedef enum rtems_rtl_unresolved_rtype_e +{ + rtems_rtl_unresolved_empty = 0, /**< The records is empty. Must always be 0 */ + rtems_rtl_unresolved_name = 1, /**< The record is a name. */ + rtems_rtl_unresolved_reloc = 2 /**< The record is a relocation record. */ +} rtems_rtl_unresolved_rtype_t; + +/** + * Unresolved externals symbol names. The names are reference counted and + * separate from the relocation records because a number of records could + * reference the same symbol name. + */ +typedef struct rtems_rtl_unresolv_name_s +{ + uint16_t refs; /**< The number of references to this name. */ + uint16_t length; /**< The length of this name. */ + const char name[12]; /**< The symbol name. */ +} rtems_rtl_unresolv_name_t; + +/** + * Unresolved externals symbols require the relocation records to be held + * and references. + */ +typedef struct rtems_rtl_unresolv_reloc_s +{ + rtems_rtl_obj_t* obj; /**< The relocation's object file. */ + uint16_t flags; /**< Format specific flags. */ + uint16_t name; /**< The symbol's name. */ + uint16_t sect; /**< The target section. */ + rtems_rtl_word_t rel[3]; /**< Relocation record. */ +} rtems_rtl_unresolv_reloc_t; + +/** + * Unresolved externals records. + */ +typedef struct rtems_rtl_unresolv_rec_s +{ + rtems_rtl_unresolved_rtype_t type; + union + { + rtems_rtl_unresolv_name_t name; /**< The name, or */ + rtems_rtl_unresolv_reloc_t reloc; /**< the relocation record. */ + } rec; +} rtems_rtl_unresolv_rec_t; + +/** + * Unresolved blocks. + */ +typedef struct rtems_rtl_unresolv_block_s +{ + rtems_chain_node link; /**< Blocks are chained. */ + uint32_t recs; /**< The number of records in the block. */ + rtems_rtl_unresolv_rec_t rec; /**< The records. More follow. */ +} rtems_rtl_unresolv_block_t; + +/** + * Unresolved table holds the names and relocations. + */ +typedef struct rtems_rtl_unresolved_s +{ + uint32_t marker; + size_t block_recs; /**< The records per blocks allocated. */ + rtems_chain_control blocks; /**< List of blocks. */ +} rtems_rtl_unresolved_t; + +/** + * The iterator function used to iterate over the unresolved table. + * + * @param rec The current iterator. + * @param data The user data. + * @retval true The iterator has finished. + * @retval false The iterator has not finished. Keep iterating. + */ +typedef bool rtems_rtl_unresolved_iterator_t (rtems_rtl_unresolv_rec_t* rec, + void* data); + +/** + * Open an unresolved relocation table. + * + * @param unresolv The unresolved table to open. + * @param block_records The number of records per block allocated. + * @retval true The table is open. + * @retval false The unresolved relocation table could not created. The RTL + * error has the error. + */ +bool rtems_rtl_unresolved_table_open (rtems_rtl_unresolved_t* unresolved, + size_t block_records); + +/** + * Close the table and erase the blocks. + * + * @param unreolved Close the unresolved table. + */ +void rtems_rtl_unresolved_table_close (rtems_rtl_unresolved_t* unresolved); + +/** + * Iterate over the table of unresolved entries. + */ +bool rtems_rtl_unresolved_interate (rtems_rtl_unresolved_iterator_t iterator, + void* data); + +/** + * Add a relocation to the list of unresolved relocations. + * + * @param unresolved The unresolved symbol table. + * @param obj The object table the symbols are for. + * @param flags Format specific flags. + * @param name The symbol name the relocation references. + * @param sect The target section number the relocation references. + * @param rel The format specific relocation data. + * @retval true The relocation has been added. + * @retval false The relocation could not be added. + */ +bool rtems_rtl_unresolved_add (rtems_rtl_obj_t* obj, + const uint16_t flags, + const char* name, + const uint16_t sect, + const rtems_rtl_word_t* rel); + +/** + * Resolve the unresolved symbols. + */ +void rtems_rtl_unresolved_resolve (void); + +/** + * Remove a relocation from the list of unresolved relocations. + * + * @param unresolved The unresolved symbol table. + * @param obj The object table the symbols are for. + * @param esyms The exported symbol table. + * @param size The size of the table in bytes. + */ +bool rtems_rtl_unresolved_remove (rtems_rtl_obj_t* obj, + const char* name, + const uint16_t sect, + const rtems_rtl_word_t* rel); + +#ifdef __cplusplus +} +#endif /* __cplusplus */ + +#endif |