[git commit] bc: fix for() to not leave data on stack
Denys Vlasenko
vda.linux at googlemail.com
Fri Dec 21 19:29:34 UTC 2018
commit: https://git.busybox.net/busybox/commit/?id=19eee8ed7cf32de37afa53ce56c62376c880a5a8
branch: https://git.busybox.net/busybox/commit/?id=refs/heads/master
function old new delta
zbc_parse_stmt_possibly_auto 1665 1697 +32
zbc_vm_process 672 701 +29
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 2/0 up/down: 61/0) Total: 61 bytes
text data bss dec hex filename
981656 485 7296 989437 f18fd busybox_old
981748 485 7296 989529 f1959 busybox_unstripped
Signed-off-by: Denys Vlasenko <vda.linux at googlemail.com>
---
miscutils/bc.c | 48 +++++++++++++++++++++++-------------------------
testsuite/bc.tests | 15 +++++++++++++++
2 files changed, 38 insertions(+), 25 deletions(-)
diff --git a/miscutils/bc.c b/miscutils/bc.c
index 50e5457b9..441cb0467 100644
--- a/miscutils/bc.c
+++ b/miscutils/bc.c
@@ -170,6 +170,8 @@
#define DEBUG_LEXER 0
#define DEBUG_COMPILE 0
#define DEBUG_EXEC 0
+// This can be left enabled for production as well:
+#define SANITY_CHECKS 1
#if DEBUG_LEXER
static uint8_t lex_indent;
@@ -1218,8 +1220,6 @@ static char** bc_program_const(size_t idx)
IF_DC(return bc_vec_item(&G.prog.consts, idx);)
}
-
-
static int bc_id_cmp(const void *e1, const void *e2)
{
return strcmp(((const BcId *) e1)->name, ((const BcId *) e2)->name);
@@ -4227,12 +4227,15 @@ static BC_STATUS zbc_parse_for(BcParse *p)
s = zbc_lex_next(&p->l);
if (s) RETURN_STATUS(s);
- if (p->l.t.t != BC_LEX_SCOLON)
+ if (p->l.t.t != BC_LEX_SCOLON) {
s = zbc_parse_expr(p, 0);
- else
+ bc_parse_push(p, BC_INST_POP);
+ if (s) RETURN_STATUS(s);
+ } else {
s = bc_POSIX_does_not_allow_empty_X_expression_in_for("init");
+ IF_ERROR_RETURN_POSSIBLE(if (s) RETURN_STATUS(s);)
+ }
- if (s) RETURN_STATUS(s);
if (p->l.t.t != BC_LEX_SCOLON) RETURN_STATUS(bc_error_bad_token());
s = zbc_lex_next(&p->l);
if (s) RETURN_STATUS(s);
@@ -4254,8 +4257,8 @@ static BC_STATUS zbc_parse_for(BcParse *p)
bc_parse_pushNUM(p);
s = bc_POSIX_does_not_allow_empty_X_expression_in_for("condition");
}
-
if (s) RETURN_STATUS(s);
+
if (p->l.t.t != BC_LEX_SCOLON) RETURN_STATUS(bc_error_bad_token());
s = zbc_lex_next(&p->l);
@@ -4267,12 +4270,14 @@ static BC_STATUS zbc_parse_for(BcParse *p)
bc_vec_push(&p->conds, &update_idx);
bc_vec_push(&p->func->labels, &p->func->code.len);
- if (p->l.t.t != BC_LEX_RPAREN)
+ if (p->l.t.t != BC_LEX_RPAREN) {
s = zbc_parse_expr(p, 0);
- else
+ bc_parse_push(p, BC_INST_POP);
+ if (s) RETURN_STATUS(s);
+ } else {
s = bc_POSIX_does_not_allow_empty_X_expression_in_for("update");
-
- if (s) RETURN_STATUS(s);
+ 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);
@@ -6434,12 +6439,13 @@ static BC_STATUS zbc_program_exec(void)
BcFunc *func = bc_program_func(ip->func);
char *code = func->code.v;
- dbg_exec("func:%zd bytes:%zd ip:%zd", ip->func, func->code.len, ip->idx);
+ dbg_exec("func:%zd bytes:%zd ip:%zd results.len:%d",
+ ip->func, func->code.len, ip->idx, G.prog.results.len);
while (ip->idx < func->code.len) {
BcStatus s = BC_STATUS_SUCCESS;
char inst = code[ip->idx++];
- dbg_exec("inst at %zd:%d", ip->idx - 1, inst);
+ dbg_exec("inst at %zd:%d results.len:%d", ip->idx - 1, inst, G.prog.results.len);
switch (inst) {
#if ENABLE_BC
case BC_INST_JUMP_ZERO: {
@@ -6671,7 +6677,6 @@ static BC_STATUS zbc_program_exec(void)
}
fflush_and_check();
-
}
RETURN_STATUS(BC_STATUS_SUCCESS);
@@ -6723,23 +6728,16 @@ static BC_STATUS zbc_vm_process(const char *text)
// storage.
if (IS_BC) {
BcFunc *f;
- BcInstPtr *ip;
-
- //FIXME: this does not clear up the stack
- //for(i=1; i<3; i++) {
- // i
- // if(i==2) continue
- // 77
- //}
-// if (G.prog.results.len != 0)
-// bb_error_msg_and_die("data stack not empty: %d slots", G.prog.results.len);
+ BcInstPtr *ip = (void*)G.prog.exestack.v;
+#if SANITY_CHECKS
+ if (G.prog.results.len != 0)
+ bb_error_msg_and_die("data stack not empty: %d slots", G.prog.results.len);
if (G.prog.exestack.len != 1) // should be empty
bb_error_msg_and_die("BUG:call stack");
-
- ip = (void*)G.prog.exestack.v;
if (ip->func != BC_PROG_MAIN)
bb_error_msg_and_die("BUG:not MAIN");
+#endif
//bb_error_msg("ip->func:%d >idx:%d >len:%d", ip->func, ip->idx, ip->len);
f = bc_program_func_BC_PROG_MAIN();
//bb_error_msg("MAIN->code.len:%d >strs.len:%d >consts.len:%d", f->code.len, f->strs.len, f->consts.len); // labels, autos, nparams
diff --git a/testsuite/bc.tests b/testsuite/bc.tests
index edff209bb..b3ce894ee 100755
--- a/testsuite/bc.tests
+++ b/testsuite/bc.tests
@@ -56,6 +56,21 @@ testing "bc for(;;)" \
"2\n3\n2\n9\n" \
"" "i=2; for (;;) { 2; if(--i==0) break; 3; }; 9"
+testing "bc for (;cond;)" \
+ "bc" \
+ "1\n2\n3\n9\n" \
+ "" "i=0; for(;i<3;)++i; 9"
+
+testing "bc for (;cond;upd)" \
+ "bc" \
+ "1\n2\n3\n9\n" \
+ "" "i=1; for(;i<4;i++)i; 9"
+
+testing "bc for (init;cond;upd)" \
+ "bc" \
+ "1\n2\n3\n9\n" \
+ "" "for(i=1;i<4;i++)i; 9"
+
testing "bc define auto" \
"bc" \
"8\n9\n" \
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