[git commit] bc: shrink zbc_parse_if() a bit more

Denys Vlasenko vda.linux at googlemail.com
Sun Dec 16 20:41:17 UTC 2018


commit: https://git.busybox.net/busybox/commit/?id=15850832be164b941aeef7c62aaed91fb5774f8a
branch: https://git.busybox.net/busybox/commit/?id=refs/heads/master

function                                             old     new   delta
zbc_parse_stmt_possibly_auto                        2180    2106     -74
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-74)             Total: -74 bytes
   text	   data	    bss	    dec	    hex	filename
 982152	    485	   7296	 989933	  f1aed	busybox_old
 982078	    485	   7296	 989859	  f1aa3	busybox_unstripped

Signed-off-by: Denys Vlasenko <vda.linux at googlemail.com>
---
 miscutils/bc.c | 30 ++++++++++++++----------------
 1 file changed, 14 insertions(+), 16 deletions(-)

diff --git a/miscutils/bc.c b/miscutils/bc.c
index 178cd7a24..2a9f3e2d3 100644
--- a/miscutils/bc.c
+++ b/miscutils/bc.c
@@ -4109,7 +4109,7 @@ static BC_STATUS zbc_parse_return(BcParse *p)
 static BC_STATUS zbc_parse_if(BcParse *p)
 {
 	BcStatus s;
-	BcInstPtr ip;
+	size_t ip_idx;
 	size_t *label;
 
 	dbg_lex_enter("%s:%d entered", __func__, __LINE__);
@@ -4128,41 +4128,39 @@ static BC_STATUS zbc_parse_if(BcParse *p)
 	if (s) RETURN_STATUS(s);
 
 	bc_parse_push(p, BC_INST_JUMP_ZERO);
-	ip.idx = p->func->labels.len;
-	ip.func = ip.len = 0;
-	bc_parse_pushIndex(p, ip.idx);
-	bc_vec_push(&p->func->labels, &ip.idx);
+	ip_idx = p->func->labels.len;
+	bc_parse_pushIndex(p, ip_idx);
+	bc_vec_push(&p->func->labels, &ip_idx);
 
 	s = zbc_parse_stmt_fail_if_bare_NLINE(p, false, "if");
 	if (s) RETURN_STATUS(s);
 
 	dbg_lex("%s:%d in if after stmt: p->l.t.t:%d", __func__, __LINE__, p->l.t.t);
 	if (p->l.t.t == BC_LEX_KEY_ELSE) {
-		BcInstPtr ip2;
+		size_t ip2_idx;
 
 		s = zbc_lex_next_and_skip_NLINE(&p->l);
 		if (s) RETURN_STATUS(s);
 
-		ip2.idx = p->func->labels.len;
-		ip2.func = ip2.len = 0;
+		ip2_idx = p->func->labels.len;
 
-		dbg_lex("%s:%d after if() body: BC_INST_JUMP to %d", __func__, __LINE__, ip.idx);
+		dbg_lex("%s:%d after if() body: BC_INST_JUMP to %d", __func__, __LINE__, ip2_idx);
 		bc_parse_push(p, BC_INST_JUMP);
-		bc_parse_pushIndex(p, ip2.idx);
+		bc_parse_pushIndex(p, ip2_idx);
 
-		label = bc_vec_item(&p->func->labels, ip.idx);
-		dbg_lex("%s:%d rewriting label: %d -> %d", __func__, __LINE__, *label, p->func->code.len);
+		label = bc_vec_item(&p->func->labels, ip_idx);
+		dbg_lex("%s:%d rewriting 'if_zero' label to jump to 'else': %d -> %d", __func__, __LINE__, *label, p->func->code.len);
 		*label = p->func->code.len;
 
-		bc_vec_push(&p->func->labels, &ip2.idx);
-		ip.idx = ip2.idx;
+		bc_vec_push(&p->func->labels, &ip2_idx);
+		ip_idx = ip2_idx;
 
 		s = zbc_parse_stmt_fail_if_bare_NLINE(p, false, "else");
 		if (s) RETURN_STATUS(s);
 	}
 
-	label = bc_vec_item(&p->func->labels, ip.idx);
-	dbg_lex("%s:%d rewriting label: %d -> %d", __func__, __LINE__, *label, p->func->code.len);
+	label = bc_vec_item(&p->func->labels, ip_idx);
+	dbg_lex("%s:%d rewriting label to jump after 'if' body: %d -> %d", __func__, __LINE__, *label, p->func->code.len);
 	*label = p->func->code.len;
 
 	dbg_lex_done("%s:%d done", __func__, __LINE__);


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