[PATCH 1/3] posix: Remove alloca usage on regex set_regs
Darshit Shah
darnir@gnu.org
Sat Jan 9 01:24:13 GMT 2021
Hi,
Since this patch has been applied, GNU Wget fails during the linking
stage due to regmatch_list_free not being available:
/usr/bin/ld: ../lib/libgnu.a(regex.o): in function `set_regs':
/home/rincewind/Programming/wget/lib/regexec.c:1444: undefined reference
to `regmatch_list_free'
/usr/bin/ld: /home/rincewind/Programming/wget/lib/regexec.c:1421:
undefined reference to `regmatch_list_free'
/usr/bin/ld: /home/rincewind/Programming/wget/lib/regexec.c:1454:
undefined reference to `regmatch_list_free'
/usr/bin/ld: /home/rincewind/Programming/wget/lib/regexec.c:1444:
undefined reference to `regmatch_list_free'
/usr/bin/ld: /home/rincewind/Programming/wget/lib/regexec.c:1430:
undefined reference to `regmatch_list_free'
/usr/bin/ld:
../lib/libgnu.a(regex.o):/home/rincewind/Programming/wget/lib/regexec.c:1460:
more undefined references to `regmatch_list_free' follow
On 06.01.21 19:17, Adhemerval Zanella wrote:
> It replaces the regmatch_t with a dynarray list.
>
> Checked on x86_64-linux-gnu.
> ---
> posix/regexec.c | 62 ++++++++++++++++++++++++-------------------------
> 1 file changed, 31 insertions(+), 31 deletions(-)
>
> diff --git a/posix/regexec.c b/posix/regexec.c
> index b083342f77..5e22f90842 100644
> --- a/posix/regexec.c
> +++ b/posix/regexec.c
> @@ -54,9 +54,6 @@ static Idx check_matching (re_match_context_t *mctx, bool fl_longest_match,
> Idx *p_match_first);
> static Idx check_halt_state_context (const re_match_context_t *mctx,
> const re_dfastate_t *state, Idx idx);
> -static void update_regs (const re_dfa_t *dfa, regmatch_t *pmatch,
> - regmatch_t *prev_idx_match, Idx cur_node,
> - Idx cur_idx, Idx nmatch);
> static reg_errcode_t push_fail_stack (struct re_fail_stack_t *fs,
> Idx str_idx, Idx dest_node, Idx nregs,
> regmatch_t *regs,
> @@ -1355,6 +1352,16 @@ pop_fail_stack (struct re_fail_stack_t *fs, Idx *pidx, Idx nregs,
> return fs->stack[num].node;
> }
>
> +
> +#define DYNARRAY_STRUCT regmatch_list
> +#define DYNARRAY_ELEMENT regmatch_t
> +#define DYNARRAY_PREFIX regmatch_list_
> +#include <malloc/dynarray-skeleton.c>
> +
> +static void update_regs (const re_dfa_t *dfa, regmatch_t *pmatch,
> + struct regmatch_list *prev_idx_match, Idx cur_node,
> + Idx cur_idx, Idx nmatch);
> +
> /* Set the positions where the subexpressions are starts/ends to registers
> PMATCH.
> Note: We assume that pmatch[0] is already set, and
> @@ -1370,8 +1377,8 @@ set_regs (const regex_t *preg, const re_match_context_t *mctx, size_t nmatch,
> re_node_set eps_via_nodes;
> struct re_fail_stack_t *fs;
> struct re_fail_stack_t fs_body = { 0, 2, NULL };
> - regmatch_t *prev_idx_match;
> - bool prev_idx_match_malloced = false;
> + struct regmatch_list prev_idx_match;
> + regmatch_list_init (&prev_idx_match);
>
> DEBUG_ASSERT (nmatch > 1);
> DEBUG_ASSERT (mctx->state_log != NULL);
> @@ -1388,23 +1395,18 @@ set_regs (const regex_t *preg, const re_match_context_t *mctx, size_t nmatch,
> cur_node = dfa->init_node;
> re_node_set_init_empty (&eps_via_nodes);
>
> - if (__libc_use_alloca (nmatch * sizeof (regmatch_t)))
> - prev_idx_match = (regmatch_t *) alloca (nmatch * sizeof (regmatch_t));
> - else
> + if (!regmatch_list_resize (&prev_idx_match, nmatch))
> {
> - prev_idx_match = re_malloc (regmatch_t, nmatch);
> - if (prev_idx_match == NULL)
> - {
> - free_fail_stack_return (fs);
> - return REG_ESPACE;
> - }
> - prev_idx_match_malloced = true;
> + regmatch_list_free (&prev_idx_match);
> + free_fail_stack_return (fs);
> + return REG_ESPACE;
> }
> - memcpy (prev_idx_match, pmatch, sizeof (regmatch_t) * nmatch);
> + for (size_t i = 0; i < nmatch; i++)
> + *regmatch_list_at (&prev_idx_match, i) = pmatch[i];
>
> for (idx = pmatch[0].rm_so; idx <= pmatch[0].rm_eo ;)
> {
> - update_regs (dfa, pmatch, prev_idx_match, cur_node, idx, nmatch);
> + update_regs (dfa, pmatch, &prev_idx_match, cur_node, idx, nmatch);
>
> if (idx == pmatch[0].rm_eo && cur_node == mctx->last_node)
> {
> @@ -1417,8 +1419,7 @@ set_regs (const regex_t *preg, const re_match_context_t *mctx, size_t nmatch,
> if (reg_idx == nmatch)
> {
> re_node_set_free (&eps_via_nodes);
> - if (prev_idx_match_malloced)
> - re_free (prev_idx_match);
> + regmatch_list_free (&prev_idx_match);
> return free_fail_stack_return (fs);
> }
> cur_node = pop_fail_stack (fs, &idx, nmatch, pmatch,
> @@ -1427,8 +1428,7 @@ set_regs (const regex_t *preg, const re_match_context_t *mctx, size_t nmatch,
> else
> {
> re_node_set_free (&eps_via_nodes);
> - if (prev_idx_match_malloced)
> - re_free (prev_idx_match);
> + regmatch_list_free (&prev_idx_match);
> return REG_NOERROR;
> }
> }
> @@ -1442,8 +1442,7 @@ set_regs (const regex_t *preg, const re_match_context_t *mctx, size_t nmatch,
> if (__glibc_unlikely (cur_node == -2))
> {
> re_node_set_free (&eps_via_nodes);
> - if (prev_idx_match_malloced)
> - re_free (prev_idx_match);
> + regmatch_list_free (&prev_idx_match);
> free_fail_stack_return (fs);
> return REG_ESPACE;
> }
> @@ -1453,15 +1452,13 @@ set_regs (const regex_t *preg, const re_match_context_t *mctx, size_t nmatch,
> else
> {
> re_node_set_free (&eps_via_nodes);
> - if (prev_idx_match_malloced)
> - re_free (prev_idx_match);
> + regmatch_list_free (&prev_idx_match);
> return REG_NOMATCH;
> }
> }
> }
> re_node_set_free (&eps_via_nodes);
> - if (prev_idx_match_malloced)
> - re_free (prev_idx_match);
> + regmatch_list_free (&prev_idx_match);
> return free_fail_stack_return (fs);
> }
>
> @@ -1483,7 +1480,8 @@ free_fail_stack_return (struct re_fail_stack_t *fs)
>
> static void
> update_regs (const re_dfa_t *dfa, regmatch_t *pmatch,
> - regmatch_t *prev_idx_match, Idx cur_node, Idx cur_idx, Idx nmatch)
> + struct regmatch_list *prev_idx_match, Idx cur_node, Idx cur_idx,
> + Idx nmatch)
> {
> int type = dfa->nodes[cur_node].type;
> if (type == OP_OPEN_SUBEXP)
> @@ -1508,18 +1506,20 @@ update_regs (const re_dfa_t *dfa, regmatch_t *pmatch,
> pmatch[reg_num].rm_eo = cur_idx;
> /* This is a non-empty match or we are not inside an optional
> subexpression. Accept this right away. */
> - memcpy (prev_idx_match, pmatch, sizeof (regmatch_t) * nmatch);
> + for (size_t i = 0; i < nmatch; i++)
> + *regmatch_list_at (prev_idx_match, i) = pmatch[i];
> }
> else
> {
> if (dfa->nodes[cur_node].opt_subexp
> - && prev_idx_match[reg_num].rm_so != -1)
> + && regmatch_list_at (prev_idx_match, reg_num)->rm_so != -1)
> /* We transited through an empty match for an optional
> subexpression, like (a?)*, and this is not the subexp's
> first match. Copy back the old content of the registers
> so that matches of an inner subexpression are undone as
> well, like in ((a?))*. */
> - memcpy (pmatch, prev_idx_match, sizeof (regmatch_t) * nmatch);
> + memcpy (pmatch, regmatch_list_begin (prev_idx_match),
> + sizeof (regmatch_t) * nmatch);
> else
> /* We completed a subexpression, but it may be part of
> an optional one, so do not update PREV_IDX_MATCH. */
>
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