diff options
| -rw-r--r-- | sys/kern/link_elf_obj.c | 42 | ||||
| -rw-r--r-- | sys/sys/elf_common.h | 3 |
2 files changed, 43 insertions, 2 deletions
diff --git a/sys/kern/link_elf_obj.c b/sys/kern/link_elf_obj.c index 0334779..4f40258 100644 --- a/sys/kern/link_elf_obj.c +++ b/sys/kern/link_elf_obj.c @@ -173,6 +173,7 @@ static struct linker_class link_elf_class = { }; static int relocate_file(elf_file_t ef); +static void elf_obj_cleanup_globals_cache(elf_file_t); static void link_elf_error(const char *filename, const char *s) @@ -1046,6 +1047,13 @@ relocate_file(elf_file_t ef) } } + /* + * Only clean SHN_FBSD_CACHED for successfull return. If we + * modified symbol table for the object but found an + * unresolved symbol, there is no reason to roll back. + */ + elf_obj_cleanup_globals_cache(ef); + return 0; } @@ -1194,6 +1202,21 @@ link_elf_each_function_nameval(linker_file_t file, return (0); } +static void +elf_obj_cleanup_globals_cache(elf_file_t ef) +{ + Elf_Sym *sym; + Elf_Size i; + + for (i = 0; i < ef->ddbsymcnt; i++) { + sym = ef->ddbsymtab + i; + if (sym->st_shndx == SHN_FBSD_CACHED) { + sym->st_shndx = SHN_UNDEF; + sym->st_value = 0; + } + } +} + /* * Symbol lookup function that can be used when the symbol index is known (ie * in relocations). It uses the symbol index instead of doing a fully fledged @@ -1205,7 +1228,7 @@ static Elf_Addr elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps) { elf_file_t ef = (elf_file_t)lf; - const Elf_Sym *sym; + Elf_Sym *sym; const char *symbol; Elf_Addr ret; @@ -1233,7 +1256,22 @@ elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps) if (*symbol == 0) return (0); ret = ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps)); - return ret; + + /* + * Cache global lookups during module relocation. The failure + * case is particularly expensive for callers, who must scan + * through the entire globals table doing strcmp(). Cache to + * avoid doing such work repeatedly. + * + * After relocation is complete, undefined globals will be + * restored to SHN_UNDEF in elf_obj_cleanup_globals_cache(), + * above. + */ + if (ret != 0) { + sym->st_shndx = SHN_FBSD_CACHED; + sym->st_value = ret; + } + return (ret); case STB_WEAK: printf("link_elf_obj: Weak symbols not supported\n"); diff --git a/sys/sys/elf_common.h b/sys/sys/elf_common.h index 2a29dd4..44f9996 100644 --- a/sys/sys/elf_common.h +++ b/sys/sys/elf_common.h @@ -251,6 +251,9 @@ typedef struct { #define SHN_LOPROC 0xff00 /* First processor-specific. */ #define SHN_HIPROC 0xff1f /* Last processor-specific. */ #define SHN_LOOS 0xff20 /* First operating system-specific. */ +#define SHN_FBSD_CACHED SHN_LOOS /* Transient, for sys/kern/link_elf_obj + linker only: Cached global in local + symtab. */ #define SHN_HIOS 0xff3f /* Last operating system-specific. */ #define SHN_ABS 0xfff1 /* Absolute values. */ #define SHN_COMMON 0xfff2 /* Common data. */ |
