diff options
| -rw-r--r-- | coreutils/test.c | 5 | ||||
| -rw-r--r-- | include/libbb.h | 34 | ||||
| -rw-r--r-- | libbb/appletlib.c | 3 | ||||
| -rw-r--r-- | libbb/lineedit.c | 5 | ||||
| -rw-r--r-- | procps/powertop.c | 2 | ||||
| -rw-r--r-- | shell/ash.c | 23 |
6 files changed, 34 insertions, 38 deletions
diff --git a/coreutils/test.c b/coreutils/test.c index 7c6574334..fc956724b 100644 --- a/coreutils/test.c +++ b/coreutils/test.c @@ -435,7 +435,7 @@ struct test_statics { }; /* See test_ptr_hack.c */ -extern struct test_statics *const test_ptr_to_statics; +extern struct test_statics *BB_GLOBAL_CONST test_ptr_to_statics; #define S (*test_ptr_to_statics) #define args (S.args ) @@ -446,8 +446,7 @@ extern struct test_statics *const test_ptr_to_statics; #define leaving (S.leaving ) #define INIT_S() do { \ - (*(struct test_statics**)not_const_pp(&test_ptr_to_statics)) = xzalloc(sizeof(S)); \ - barrier(); \ + ASSIGN_CONST_PTR(test_ptr_to_statics, xzalloc(sizeof(S))); \ } while (0) #define DEINIT_S() do { \ free(group_array); \ diff --git a/include/libbb.h b/include/libbb.h index dfcaa05ec..02cc008f0 100644 --- a/include/libbb.h +++ b/include/libbb.h @@ -365,13 +365,27 @@ struct BUG_off_t_size_is_misdetected { #endif #endif +/* We use a trick to have more optimized code (fewer pointer reloads + * and reduced binary size by a few kilobytes) like: + * ash.c: extern struct globals *const ash_ptr_to_globals; + * ash_ptr_hack.c: struct globals *ash_ptr_to_globals; + * This way, compiler in ash.c knows the pointer can not change. + * + * However, this may break on weird arches or toolchains. In this case, + * set "-DBB_GLOBAL_CONST=''" in CONFIG_EXTRA_CFLAGS to disable + * this optimization. + */ +#ifndef BB_GLOBAL_CONST +# define BB_GLOBAL_CONST const +#endif + #if defined(errno) /* If errno is a define, assume it's "define errno (*__errno_location())" * and we will cache it's result in this variable */ -extern int *const bb_errno; -#undef errno -#define errno (*bb_errno) -#define bb_cached_errno_ptr 1 +extern int *BB_GLOBAL_CONST bb_errno; +# undef errno +# define errno (*bb_errno) +# define bb_cached_errno_ptr 1 #endif #if !(ULONG_MAX > 0xffffffff) @@ -2270,6 +2284,8 @@ struct globals; * If you want to assign a value, use SET_PTR_TO_GLOBALS(x) */ extern struct globals *const ptr_to_globals; +#define barrier() asm volatile ("":::"memory") + #if defined(__clang_major__) && __clang_major__ >= 9 /* Clang/llvm drops assignment to "constant" storage. Silently. * Needs serious convincing to not eliminate the store. @@ -2277,7 +2293,7 @@ extern struct globals *const ptr_to_globals; static ALWAYS_INLINE void* not_const_pp(const void *p) { void *pp; - __asm__ __volatile__( + asm volatile ( "# forget that p points to const" : /*outputs*/ "=r" (pp) : /*inputs*/ "0" (p) @@ -2288,13 +2304,13 @@ static ALWAYS_INLINE void* not_const_pp(const void *p) static ALWAYS_INLINE void* not_const_pp(const void *p) { return (void*)p; } #endif -/* At least gcc 3.4.6 on mipsel system needs optimization barrier */ -#define barrier() __asm__ __volatile__("":::"memory") -#define SET_PTR_TO_GLOBALS(x) do { \ - (*(struct globals**)not_const_pp(&ptr_to_globals)) = (void*)(x); \ +#define ASSIGN_CONST_PTR(p, v) do { \ + *(void**)not_const_pp(&p) = (void*)(v); \ + /* At least gcc 3.4.6 on mipsel needs optimization barrier */ \ barrier(); \ } while (0) +#define SET_PTR_TO_GLOBALS(x) ASSIGN_CONST_PTR(ptr_to_globals, x) #define FREE_PTR_TO_GLOBALS() do { \ if (ENABLE_FEATURE_CLEAN_UP) { \ free(ptr_to_globals); \ diff --git a/libbb/appletlib.c b/libbb/appletlib.c index 5c5d7eb95..bf26c99e9 100644 --- a/libbb/appletlib.c +++ b/libbb/appletlib.c @@ -247,8 +247,7 @@ void lbb_prepare(const char *applet IF_FEATURE_INDIVIDUAL(, char **argv)) { #ifdef bb_cached_errno_ptr - (*(int **)not_const_pp(&bb_errno)) = get_perrno(); - barrier(); + ASSIGN_CONST_PTR(bb_errno, get_perrno()); #endif applet_name = applet; diff --git a/libbb/lineedit.c b/libbb/lineedit.c index a7a3ee103..3c87abcf9 100644 --- a/libbb/lineedit.c +++ b/libbb/lineedit.c @@ -192,7 +192,7 @@ struct lineedit_statics { }; /* See lineedit_ptr_hack.c */ -extern struct lineedit_statics *const lineedit_ptr_to_statics; +extern struct lineedit_statics *BB_GLOBAL_CONST lineedit_ptr_to_statics; #define S (*lineedit_ptr_to_statics) #define state (S.state ) @@ -214,8 +214,7 @@ extern struct lineedit_statics *const lineedit_ptr_to_statics; #define delbuf (S.delbuf ) #define INIT_S() do { \ - (*(struct lineedit_statics**)not_const_pp(&lineedit_ptr_to_statics)) = xzalloc(sizeof(S)); \ - barrier(); \ + ASSIGN_CONST_PTR(lineedit_ptr_to_statics, xzalloc(sizeof(S))); \ } while (0) static void deinit_S(void) diff --git a/procps/powertop.c b/procps/powertop.c index fc6018b7a..24c2b320f 100644 --- a/procps/powertop.c +++ b/procps/powertop.c @@ -505,7 +505,7 @@ static void cpuid(unsigned int *eax, unsigned int *ebx, unsigned int *ecx, unsigned int *edx) { /* EAX value specifies what information to return */ - __asm__( + asm ( " pushl %%ebx\n" /* Save EBX */ " cpuid\n" " movl %%ebx, %1\n" /* Save content of EBX */ diff --git a/shell/ash.c b/shell/ash.c index 4bf0615ea..7b85981ec 100644 --- a/shell/ash.c +++ b/shell/ash.c @@ -303,20 +303,6 @@ typedef long arith_t; # error "Do not even bother, ash will not run on NOMMU machine" #endif -/* We use a trick to have more optimized code (fewer pointer reloads): - * ash.c: extern struct globals *const ash_ptr_to_globals; - * ash_ptr_hack.c: struct globals *ash_ptr_to_globals; - * This way, compiler in ash.c knows the pointer can not change. - * - * However, this may break on weird arches or toolchains. In this case, - * set "-DBB_GLOBAL_CONST=''" in CONFIG_EXTRA_CFLAGS to disable - * this optimization. - */ -#ifndef BB_GLOBAL_CONST -# define BB_GLOBAL_CONST const -#endif - - /* ============ Hash table sizes. Configurable. */ #define VTABSIZE 39 @@ -518,8 +504,7 @@ extern struct globals_misc *BB_GLOBAL_CONST ash_ptr_to_globals_misc; #define random_gen (G_misc.random_gen ) #define backgndpid (G_misc.backgndpid ) #define INIT_G_misc() do { \ - (*(struct globals_misc**)not_const_pp(&ash_ptr_to_globals_misc)) = xzalloc(sizeof(G_misc)); \ - barrier(); \ + ASSIGN_CONST_PTR(ash_ptr_to_globals_misc, xzalloc(sizeof(G_misc))); \ savestatus = -1; \ curdir = nullstr; \ physdir = nullstr; \ @@ -1597,8 +1582,7 @@ extern struct globals_memstack *BB_GLOBAL_CONST ash_ptr_to_globals_memstack; #define g_stacknleft (G_memstack.g_stacknleft) #define stackbase (G_memstack.stackbase ) #define INIT_G_memstack() do { \ - (*(struct globals_memstack**)not_const_pp(&ash_ptr_to_globals_memstack)) = xzalloc(sizeof(G_memstack)); \ - barrier(); \ + ASSIGN_CONST_PTR(ash_ptr_to_globals_memstack, xzalloc(sizeof(G_memstack))); \ g_stackp = &stackbase; \ g_stacknxt = stackbase.space; \ g_stacknleft = MINSIZE; \ @@ -2229,8 +2213,7 @@ extern struct globals_var *BB_GLOBAL_CONST ash_ptr_to_globals_var; #endif #define INIT_G_var() do { \ unsigned i; \ - (*(struct globals_var**)not_const_pp(&ash_ptr_to_globals_var)) = xzalloc(sizeof(G_var)); \ - barrier(); \ + ASSIGN_CONST_PTR(ash_ptr_to_globals_var, xzalloc(sizeof(G_var))); \ for (i = 0; i < ARRAY_SIZE(varinit_data); i++) { \ varinit[i].flags = varinit_data[i].flags; \ varinit[i].var_text = varinit_data[i].var_text; \ |