bc: rewrite "block flag stack" using simple realloc'ed byte array
Each access to current top flag took a function call + fetch of three data items + multiplication and some additions + and then following the resulting pointer. After the change, it is: fetch pointer value + one byte access via this pointer. function old new delta bc_parse_startBody 45 49 +4 bc_parse_free 46 47 +1 zbc_parse_auto 188 185 -3 bc_parse_push 14 11 -3 bc_vm_run 398 394 -4 zbc_vm_process 63 58 -5 zdc_parse_expr 638 632 -6 zbc_parse_body 101 95 -6 bc_parse_addFunc 31 25 -6 bc_parse_noElse 56 48 -8 zcommon_parse 341 331 -10 zbc_parse_else 134 123 -11 bc_parse_create 124 108 -16 zbc_parse_text_init 123 104 -19 zbc_parse_endBody 292 252 -40 zbc_parse_stmt 1479 1420 -59 ------------------------------------------------------------------------------ (add/remove: 0/0 grow/shrink: 2/14 up/down: 5/-196) Total: -191 bytes text data bss dec hex filename 979880 485 7296 987661 f120d busybox_old 979689 485 7296 987470 f114e busybox_unstripped Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko
parent
f10f17f8d3
commit
7db384338a
@ -574,8 +574,9 @@ typedef struct BcLex {
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#define BC_PARSE_NOREAD (1 << 3)
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#define BC_PARSE_ARRAY (1 << 4)
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#define BC_PARSE_TOP_FLAG_PTR(parse) ((uint8_t *) bc_vec_top(&(parse)->flags))
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#define BC_PARSE_TOP_FLAG_PTR(parse) ((parse)->bf_top)
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#define BC_PARSE_TOP_FLAG(parse) (*(BC_PARSE_TOP_FLAG_PTR(parse)))
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#define BC_PARSE_FLAG_STACK_EMPTY(p) ((p)->bf_top == (p)->bf_base)
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#define BC_PARSE_FLAG_FUNC_INNER (1 << 0)
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#define BC_PARSE_FLAG_FUNC (1 << 1)
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@ -598,15 +599,11 @@ typedef struct BcLex {
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#define BC_PARSE_ELSE(parse) (BC_PARSE_TOP_FLAG(parse) & BC_PARSE_FLAG_ELSE)
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#define BC_PARSE_IF_END(parse) (BC_PARSE_TOP_FLAG(parse) & BC_PARSE_FLAG_IF_END)
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struct BcParse;
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struct BcProgram;
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typedef struct BcParse {
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BcLex l;
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BcVec flags;
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uint8_t *bf_base;
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uint8_t *bf_top;
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BcVec exits;
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BcVec conds;
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@ -618,7 +615,6 @@ typedef struct BcParse {
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size_t nbraces;
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bool auto_part;
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} BcParse;
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typedef struct BcProgram {
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@ -3558,7 +3554,7 @@ static void bc_parse_reset(BcParse *p)
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p->l.t.t = BC_LEX_EOF;
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p->auto_part = (p->nbraces = 0);
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bc_vec_npop(&p->flags, p->flags.len - 1);
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p->bf_top = p->bf_base; // pop all flags
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bc_vec_pop_all(&p->exits);
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bc_vec_pop_all(&p->conds);
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bc_vec_pop_all(&p->ops);
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@ -3568,7 +3564,7 @@ static void bc_parse_reset(BcParse *p)
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static void bc_parse_free(BcParse *p)
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{
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bc_vec_free(&p->flags);
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free(p->bf_base);
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bc_vec_free(&p->exits);
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bc_vec_free(&p->conds);
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bc_vec_free(&p->ops);
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@ -3580,10 +3576,9 @@ static void bc_parse_create(BcParse *p, size_t func)
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memset(p, 0, sizeof(BcParse));
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bc_lex_init(&p->l);
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bc_vec_init(&p->flags, sizeof(uint8_t), NULL);
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p->bf_top = p->bf_base = xzalloc(1);
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bc_vec_init(&p->exits, sizeof(BcInstPtr), NULL);
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bc_vec_init(&p->conds, sizeof(size_t), NULL);
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bc_vec_pushZeroByte(&p->flags);
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bc_vec_init(&p->ops, sizeof(BcLexType), NULL);
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// p->auto_part = p->nbraces = 0; - already is
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@ -4050,7 +4045,7 @@ static BC_STATUS zbc_parse_endBody(BcParse *p)
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{
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BcStatus s = BC_STATUS_SUCCESS;
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if (p->flags.len <= 1)
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if (BC_PARSE_FLAG_STACK_EMPTY(p))
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RETURN_STATUS(bc_error_bad_token());
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if (BC_PARSE_IF(p)) {
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@ -4061,7 +4056,7 @@ static BC_STATUS zbc_parse_endBody(BcParse *p)
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if (s) RETURN_STATUS(s);
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}
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bc_vec_pop(&p->flags);
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p->bf_top--;
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flag_ptr = BC_PARSE_TOP_FLAG_PTR(p);
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dbg_lex("%s:%d setting BC_PARSE_FLAG_IF_END bit", __func__, __LINE__);
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@ -4074,7 +4069,7 @@ static BC_STATUS zbc_parse_endBody(BcParse *p)
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BcInstPtr *ip;
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size_t *label;
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bc_vec_pop(&p->flags);
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p->bf_top--;
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ip = bc_vec_top(&p->exits);
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label = bc_vec_item(&p->func->labels, ip->idx);
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@ -4085,7 +4080,7 @@ static BC_STATUS zbc_parse_endBody(BcParse *p)
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else if (BC_PARSE_FUNC_INNER(p)) {
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bc_parse_push(p, BC_INST_RET0);
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bc_parse_updateFunc(p, BC_PROG_MAIN);
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bc_vec_pop(&p->flags);
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p->bf_top--;
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}
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else {
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BcInstPtr *ip = bc_vec_top(&p->exits);
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@ -4097,7 +4092,7 @@ static BC_STATUS zbc_parse_endBody(BcParse *p)
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label = bc_vec_item(&p->func->labels, ip->idx);
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*label = p->func->code.len;
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bc_vec_pop(&p->flags);
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p->bf_top--;
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bc_vec_pop(&p->exits);
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bc_vec_pop(&p->conds);
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}
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@ -4110,10 +4105,15 @@ static BC_STATUS zbc_parse_endBody(BcParse *p)
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static void bc_parse_startBody(BcParse *p, uint8_t flags)
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{
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size_t size;
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uint8_t *flag_ptr = BC_PARSE_TOP_FLAG_PTR(p);
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flags |= (*flag_ptr & (BC_PARSE_FLAG_FUNC | BC_PARSE_FLAG_LOOP));
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flags |= BC_PARSE_FLAG_BODY;
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bc_vec_push(&p->flags, &flags);
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size = p->bf_top - p->bf_base;
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p->bf_base = xrealloc(p->bf_base, size + 2);
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p->bf_top = p->bf_base + size + 1;
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*p->bf_top = flags;
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}
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static void bc_parse_noElse(BcParse *p)
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@ -4492,7 +4492,7 @@ err:
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static BC_STATUS zbc_parse_body(BcParse *p, bool brace)
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{
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BcStatus s = BC_STATUS_SUCCESS;
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uint8_t *flag_ptr = bc_vec_top(&p->flags);
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uint8_t *flag_ptr = BC_PARSE_TOP_FLAG_PTR(p);
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dbg_lex_enter("%s:%d entered", __func__, __LINE__);
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*flag_ptr &= ~(BC_PARSE_FLAG_BODY);
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@ -4535,10 +4535,12 @@ static BC_STATUS zbc_parse_stmt(BcParse *p)
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RETURN_STATUS(zbc_lex_next(&p->l));
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case BC_LEX_KEY_ELSE:
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dbg_lex("%s:%d BC_LEX_KEY_ELSE:", __func__, __LINE__);
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p->auto_part = false;
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break;
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case BC_LEX_LBRACE:
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dbg_lex("%s:%d BC_LEX_LBRACE:", __func__, __LINE__);
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if (!BC_PARSE_BODY(p)) RETURN_STATUS(bc_error_bad_token());
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++p->nbraces;
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s = zbc_lex_next(&p->l);
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@ -4547,6 +4549,7 @@ static BC_STATUS zbc_parse_stmt(BcParse *p)
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RETURN_STATUS(zbc_parse_body(p, true));
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case BC_LEX_KEY_AUTO:
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dbg_lex("%s:%d BC_LEX_KEY_AUTO:", __func__, __LINE__);
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RETURN_STATUS(zbc_parse_auto(p));
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default:
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@ -4660,7 +4663,7 @@ static BC_STATUS zbc_parse_parse(BcParse *p)
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dbg_lex_enter("%s:%d entered", __func__, __LINE__);
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if (p->l.t.t == BC_LEX_EOF)
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s = p->flags.len > 0 ? bc_error("block end could not be found") : bc_error("end of file");
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s = BC_PARSE_FLAG_STACK_EMPTY(p) ? bc_error("end of file") : bc_error("block end could not be found");
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else if (p->l.t.t == BC_LEX_KEY_DEFINE) {
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dbg_lex("%s:%d p->l.t.t:BC_LEX_KEY_DEFINE", __func__, __LINE__);
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if (!BC_PARSE_CAN_EXEC(p))
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