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authorDenys Vlasenko <vda.linux@googlemail.com>2018-12-21 22:16:17 +0100
committerDenys Vlasenko <vda.linux@googlemail.com>2018-12-21 22:16:17 +0100
commit6ed7fb0a877d550428cb289feb3695dcd2812ab8 (patch)
tree1788936bb39264041ebb6456625b65be5f6981b5
parent19eee8ed7cf32de37afa53ce56c62376c880a5a8 (diff)
downloadbusybox-6ed7fb0a877d550428cb289feb3695dcd2812ab8.tar.gz
bc: optimize bc_vec_push() usage
function old new delta bc_parse_pushNUM 87 80 -7 zbc_parse_stmt_possibly_auto 1697 1689 -8 ------------------------------------------------------------------------------ (add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-15) Total: -15 bytes Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
-rw-r--r--miscutils/bc.c58
1 files changed, 26 insertions, 32 deletions
diff --git a/miscutils/bc.c b/miscutils/bc.c
index 441cb0467..abedbdf0b 100644
--- a/miscutils/bc.c
+++ b/miscutils/bc.c
@@ -1097,24 +1097,25 @@ static void bc_vec_pop_all(BcVec *v)
bc_vec_npop(v, v->len);
}
-//TODO: return index of pushed data - many callers can use that
-static void bc_vec_push(BcVec *v, const void *data)
+static size_t bc_vec_push(BcVec *v, const void *data)
{
- if (v->len + 1 > v->cap) bc_vec_grow(v, 1);
- memmove(v->v + (v->size * v->len), data, v->size);
- v->len += 1;
+ size_t len = v->len;
+ if (len >= v->cap) bc_vec_grow(v, 1);
+ memmove(v->v + (v->size * len), data, v->size);
+ v->len++;
+ return len;
}
-static void bc_vec_pushByte(BcVec *v, char data)
+static size_t bc_vec_pushByte(BcVec *v, char data)
{
- bc_vec_push(v, &data);
+ return bc_vec_push(v, &data);
}
-static void bc_vec_pushZeroByte(BcVec *v)
+static size_t bc_vec_pushZeroByte(BcVec *v)
{
- //bc_vec_pushByte(v, '\0');
+ //return bc_vec_pushByte(v, '\0');
// better:
- bc_vec_push(v, &const_int_0);
+ return bc_vec_push(v, &const_int_0);
}
static void bc_vec_pushAt(BcVec *v, const void *data, size_t idx)
@@ -3548,14 +3549,11 @@ static void bc_parse_pushNUM(BcParse *p)
{
char *num = xstrdup(p->l.t.v.v);
#if ENABLE_BC && ENABLE_DC
- size_t idx = IS_BC ? p->func->consts.len : G.prog.consts.len;
- bc_vec_push(IS_BC ? &p->func->consts : &G.prog.consts, &num);
+ size_t idx = bc_vec_push(IS_BC ? &p->func->consts : &G.prog.consts, &num);
#elif ENABLE_BC
- size_t idx = p->func->consts.len;
- bc_vec_push(&p->func->consts, &num);
+ size_t idx = bc_vec_push(&p->func->consts, &num);
#else // DC
- size_t idx = G.prog.consts.len;
- bc_vec_push(&G.prog.consts, &num);
+ size_t idx = bc_vec_push(&G.prog.consts, &num);
#endif
bc_parse_push(p, BC_INST_NUM);
bc_parse_pushIndex(p, idx);
@@ -3652,7 +3650,7 @@ static void bc_program_add_fn(void)
//size_t idx;
BcFunc f;
bc_func_init(&f);
- //idx = G.prog.fns.len;
+ //idx =
bc_vec_push(&G.prog.fns, &f);
//return idx;
}
@@ -4135,12 +4133,13 @@ static BC_STATUS zbc_parse_if(BcParse *p)
if (s) RETURN_STATUS(s);
s = zbc_parse_expr(p, BC_PARSE_REL);
if (s) RETURN_STATUS(s);
-
if (p->l.t.t != BC_LEX_RPAREN) RETURN_STATUS(bc_error_bad_token());
- ip_idx = p->func->labels.len;
+ // Encode "if zero, jump to ..."
+ // Pushed value (destination of the jump) is uninitialized,
+ // will be rewritten to be address of "end of if()" or of "else".
+ ip_idx = bc_vec_push(&p->func->labels, &ip_idx);
bc_parse_pushJUMP_ZERO(p, ip_idx);
- bc_vec_push(&p->func->labels, &ip_idx);
s = zbc_parse_stmt_allow_NLINE_before(p, STRING_if);
if (s) RETURN_STATUS(s);
@@ -4149,15 +4148,14 @@ static BC_STATUS zbc_parse_if(BcParse *p)
if (p->l.t.t == BC_LEX_KEY_ELSE) {
size_t ip2_idx;
- ip2_idx = p->func->labels.len;
-
- dbg_lex("%s:%d after if() body: BC_INST_JUMP to %zd", __func__, __LINE__, ip2_idx);
+ // Encode "after then_stmt, jump to end of if()"
+ ip2_idx = bc_vec_push(&p->func->labels, &ip2_idx);
+ dbg_lex("%s:%d after if() then_stmt: BC_INST_JUMP to %zd", __func__, __LINE__, ip2_idx);
bc_parse_pushJUMP(p, ip2_idx);
dbg_lex("%s:%d rewriting 'if_zero' label to jump to 'else'-> %zd", __func__, __LINE__, p->func->code.len);
rewrite_label_to_current(p, ip_idx);
- bc_vec_push(&p->func->labels, &ip2_idx);
ip_idx = ip2_idx;
s = zbc_parse_stmt_allow_NLINE_before(p, STRING_else);
@@ -4184,10 +4182,8 @@ static BC_STATUS zbc_parse_while(BcParse *p)
s = zbc_lex_next(&p->l);
if (s) RETURN_STATUS(s);
- cond_idx = p->func->labels.len;
+ cond_idx = bc_vec_push(&p->func->labels, &p->func->code.len);
ip_idx = cond_idx + 1;
-
- bc_vec_push(&p->func->labels, &p->func->code.len);
bc_vec_push(&p->conds, &cond_idx);
bc_vec_push(&p->exits, &ip_idx);
@@ -4240,13 +4236,11 @@ static BC_STATUS zbc_parse_for(BcParse *p)
s = zbc_lex_next(&p->l);
if (s) RETURN_STATUS(s);
- cond_idx = p->func->labels.len;
+ cond_idx = bc_vec_push(&p->func->labels, &p->func->code.len);
update_idx = cond_idx + 1;
body_idx = update_idx + 1;
exit_idx = body_idx + 1;
- bc_vec_push(&p->func->labels, &p->func->code.len);
-
if (p->l.t.t != BC_LEX_SCOLON)
s = zbc_parse_expr(p, BC_PARSE_REL);
else {
@@ -4272,14 +4266,14 @@ static BC_STATUS zbc_parse_for(BcParse *p)
if (p->l.t.t != BC_LEX_RPAREN) {
s = zbc_parse_expr(p, 0);
- bc_parse_push(p, BC_INST_POP);
if (s) RETURN_STATUS(s);
+ if (p->l.t.t != BC_LEX_RPAREN) RETURN_STATUS(bc_error_bad_token());
+ bc_parse_push(p, BC_INST_POP);
} else {
s = bc_POSIX_does_not_allow_empty_X_expression_in_for("update");
IF_ERROR_RETURN_POSSIBLE(if (s) RETURN_STATUS(s);)
}
- if (p->l.t.t != BC_LEX_RPAREN) RETURN_STATUS(bc_error_bad_token());
bc_parse_pushJUMP(p, cond_idx);
bc_vec_push(&p->func->labels, &p->func->code.len);