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Improve early fail detection in JIT
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Zoltan Herczeg committed Dec 30, 2023
1 parent ba41b5d commit 16759fc
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Showing 2 changed files with 132 additions and 88 deletions.
219 changes: 131 additions & 88 deletions src/pcre2_jit_compile.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1269,34 +1269,37 @@ while (cc < ccend)
return TRUE;
}

#define EARLY_FAIL_ENHANCE_MAX (1 + 3)
#define EARLY_FAIL_ENHANCE_MAX (3 + 3)

/*
start:
0 - skip / early fail allowed
1 - only early fail with range allowed
>1 - (start - 1) early fail is processed
Start represent the number of allowed early fail enhancements
return: current number of iterators enhanced with fast fail
The 0-2 values has a special meaning:
0 - skip is allowed for all iterators
1 - fail is allowed for all iterators
2 - fail is allowed for greedy iterators
3 - only ranged early fail is allowed
>3 - (start - 3) number of remaining ranged early fails allowed
return: the updated value of start
*/
static int detect_early_fail(compiler_common *common, PCRE2_SPTR cc, int *private_data_start,
sljit_s32 depth, int start, BOOL fast_forward_allowed)
static int detect_early_fail(compiler_common *common, PCRE2_SPTR cc,
int *private_data_start, sljit_s32 depth, int start)
{
PCRE2_SPTR begin = cc;
PCRE2_SPTR next_alt;
PCRE2_SPTR end;
PCRE2_SPTR accelerated_start;
BOOL prev_fast_forward_allowed;
int result = 0;
int count;
int count, prev_count;

SLJIT_ASSERT(*cc == OP_ONCE || *cc == OP_BRA || *cc == OP_CBRA);
SLJIT_ASSERT(*cc != OP_CBRA || common->optimized_cbracket[GET2(cc, 1 + LINK_SIZE)] != 0);
SLJIT_ASSERT(start < EARLY_FAIL_ENHANCE_MAX);

next_alt = cc + GET(cc, 1);
if (*next_alt == OP_ALT)
fast_forward_allowed = FALSE;
if (*next_alt == OP_ALT && start < 1)
start = 1;

do
{
Expand Down Expand Up @@ -1339,39 +1342,45 @@ do
case OP_HSPACE:
case OP_NOT_VSPACE:
case OP_VSPACE:
fast_forward_allowed = FALSE;
if (count < 1)
count = 1;
cc++;
continue;

case OP_ANYNL:
case OP_EXTUNI:
fast_forward_allowed = FALSE;
if (count == 0)
count = 1;
if (count < 3)
count = 3;
cc++;
continue;

case OP_NOTPROP:
case OP_PROP:
fast_forward_allowed = FALSE;
if (count < 1)
count = 1;
cc += 1 + 2;
continue;

case OP_CHAR:
case OP_CHARI:
case OP_NOT:
case OP_NOTI:
fast_forward_allowed = FALSE;
if (count < 1)
count = 1;
cc += 2;
#ifdef SUPPORT_UNICODE
if (common->utf && HAS_EXTRALEN(cc[-1])) cc += GET_EXTRALEN(cc[-1]);
#endif
continue;

case OP_TYPESTAR:
case OP_TYPEMINSTAR:
case OP_TYPEPLUS:
case OP_TYPEMINPLUS:
if (count == 2)
count = 3;
/* Fall through */

case OP_TYPESTAR:
case OP_TYPEPLUS:
case OP_TYPEPOSSTAR:
case OP_TYPEPOSPLUS:
/* The type or prop opcode is skipped in the next iteration. */
Expand All @@ -1383,14 +1392,18 @@ do
break;
}

if (count == 0)
if (count < 3)
count = 3;
continue;

case OP_TYPEEXACT:
if (count < 1)
count = 1;
fast_forward_allowed = FALSE;
cc += 1 + IMM2_SIZE;
continue;

case OP_TYPEUPTO:
case OP_TYPEMINUPTO:
case OP_TYPEEXACT:
case OP_TYPEPOSUPTO:
cc += IMM2_SIZE;
/* Fall through */
Expand All @@ -1399,37 +1412,40 @@ do
case OP_TYPEMINQUERY:
case OP_TYPEPOSQUERY:
/* The type or prop opcode is skipped in the next iteration. */
fast_forward_allowed = FALSE;
if (count == 0)
count = 1;
if (count < 3)
count = 3;
cc += 1;
continue;

case OP_STAR:
case OP_MINSTAR:
case OP_PLUS:
case OP_MINPLUS:
case OP_MINSTARI:
case OP_MINPLUSI:
case OP_NOTMINSTAR:
case OP_NOTMINPLUS:
case OP_NOTMINSTARI:
case OP_NOTMINPLUSI:
if (count == 2)
count = 3;
/* Fall through */

case OP_STAR:
case OP_PLUS:
case OP_POSSTAR:
case OP_POSPLUS:

case OP_STARI:
case OP_MINSTARI:
case OP_PLUSI:
case OP_MINPLUSI:
case OP_POSSTARI:
case OP_POSPLUSI:

case OP_NOTSTAR:
case OP_NOTMINSTAR:
case OP_NOTPLUS:
case OP_NOTMINPLUS:
case OP_NOTPOSSTAR:
case OP_NOTPOSPLUS:

case OP_NOTSTARI:
case OP_NOTMINSTARI:
case OP_NOTPLUSI:
case OP_NOTMINPLUSI:
case OP_NOTPOSSTARI:
case OP_NOTPOSPLUSI:
accelerated_start = cc;
Expand All @@ -1439,9 +1455,17 @@ do
#endif
break;

case OP_EXACT:
if (count < 1)
count = 1;
cc += 2 + IMM2_SIZE;
#ifdef SUPPORT_UNICODE
if (common->utf && HAS_EXTRALEN(cc[-1])) cc += GET_EXTRALEN(cc[-1]);
#endif
continue;

case OP_UPTO:
case OP_MINUPTO:
case OP_EXACT:
case OP_POSUPTO:
case OP_UPTOI:
case OP_MINUPTOI:
Expand Down Expand Up @@ -1470,9 +1494,8 @@ do
case OP_NOTQUERYI:
case OP_NOTMINQUERYI:
case OP_NOTPOSQUERYI:
fast_forward_allowed = FALSE;
if (count == 0)
count = 1;
if (count < 3)
count = 3;
cc += 2;
#ifdef SUPPORT_UNICODE
if (common->utf && HAS_EXTRALEN(cc[-1])) cc += GET_EXTRALEN(cc[-1]);
Expand All @@ -1492,10 +1515,14 @@ do

switch (*cc)
{
case OP_CRSTAR:
case OP_CRMINSTAR:
case OP_CRPLUS:
case OP_CRMINPLUS:
if (count == 2)
count = 3;
/* Fall through */

case OP_CRSTAR:
case OP_CRPLUS:
case OP_CRPOSSTAR:
case OP_CRPOSPLUS:
cc++;
Expand All @@ -1504,39 +1531,58 @@ do
case OP_CRRANGE:
case OP_CRMINRANGE:
case OP_CRPOSRANGE:
if (GET2(cc, 1) == GET2(cc, 1 + IMM2_SIZE))
{
/* Exact repeat. */
cc += 1 + 2 * IMM2_SIZE;
if (count < 1)
count = 1;
continue;
}

cc += 2 * IMM2_SIZE;
/* Fall through */
case OP_CRQUERY:
case OP_CRMINQUERY:
case OP_CRPOSQUERY:
cc++;
if (count == 0)
count = 1;
/* Fall through */
if (count < 3)
count = 3;
continue;

default:
accelerated_start = NULL;
fast_forward_allowed = FALSE;
/* No repeat. */
if (count < 1)
count = 1;
continue;
}
break;

case OP_ONCE:
if (count < 2)
count = 2;
/* Fall through */

case OP_BRA:
case OP_CBRA:
prev_fast_forward_allowed = fast_forward_allowed;
fast_forward_allowed = FALSE;
prev_count = count;
if (count < 1)
count = 1;

if (depth >= 4)
break;

if (count == 0 && cc[GET(cc, 1)] == OP_ALT)
count = 1;
if (count < 3 && cc[GET(cc, 1)] == OP_ALT)
count = 3;

end = bracketend(cc);
if (end[-1 - LINK_SIZE] != OP_KET || (*cc == OP_CBRA && common->optimized_cbracket[GET2(cc, 1 + LINK_SIZE)] == 0))
break;

count = detect_early_fail(common, cc, private_data_start, depth + 1, count, prev_fast_forward_allowed);
prev_count = detect_early_fail(common, cc, private_data_start, depth + 1, prev_count);

if (prev_count > count)
count = prev_count;

if (PRIVATE_DATA(cc) != 0)
common->private_data_ptrs[begin - common->start] = 1;
Expand All @@ -1556,55 +1602,52 @@ do
continue;
}

if (accelerated_start != NULL)
if (accelerated_start == NULL)
break;

if (count == 0)
{
if (count == 0)
{
count++;
common->fast_forward_bc_ptr = accelerated_start;
common->private_data_ptrs[(accelerated_start + 1) - common->start] = ((*private_data_start) << 3) | type_skip;
*private_data_start += sizeof(sljit_sw);
count = 4;
}
else if (count < 3)
{
common->private_data_ptrs[(accelerated_start + 1) - common->start] = ((*private_data_start) << 3) | type_fail;

if (fast_forward_allowed)
{
common->fast_forward_bc_ptr = accelerated_start;
common->private_data_ptrs[(accelerated_start + 1) - common->start] = ((*private_data_start) << 3) | type_skip;
*private_data_start += sizeof(sljit_sw);
}
else
{
common->private_data_ptrs[(accelerated_start + 1) - common->start] = ((*private_data_start) << 3) | type_fail;
if (common->early_fail_start_ptr == 0)
common->early_fail_start_ptr = *private_data_start;

if (common->early_fail_start_ptr == 0)
common->early_fail_start_ptr = *private_data_start;
*private_data_start += sizeof(sljit_sw);
common->early_fail_end_ptr = *private_data_start;

*private_data_start += sizeof(sljit_sw);
common->early_fail_end_ptr = *private_data_start;
if (*private_data_start > SLJIT_MAX_LOCAL_SIZE)
return EARLY_FAIL_ENHANCE_MAX;

if (*private_data_start > SLJIT_MAX_LOCAL_SIZE)
return EARLY_FAIL_ENHANCE_MAX;
}
}
else
{
common->private_data_ptrs[(accelerated_start + 1) - common->start] = ((*private_data_start) << 3) | type_fail_range;
count = 4;
}
else
{
common->private_data_ptrs[(accelerated_start + 1) - common->start] = ((*private_data_start) << 3) | type_fail_range;

if (common->early_fail_start_ptr == 0)
common->early_fail_start_ptr = *private_data_start;
if (common->early_fail_start_ptr == 0)
common->early_fail_start_ptr = *private_data_start;

*private_data_start += 2 * sizeof(sljit_sw);
common->early_fail_end_ptr = *private_data_start;
*private_data_start += 2 * sizeof(sljit_sw);
common->early_fail_end_ptr = *private_data_start;

if (*private_data_start > SLJIT_MAX_LOCAL_SIZE)
return EARLY_FAIL_ENHANCE_MAX;
}
if (*private_data_start > SLJIT_MAX_LOCAL_SIZE)
return EARLY_FAIL_ENHANCE_MAX;

/* Cannot be part of a repeat. */
common->private_data_ptrs[begin - common->start] = 1;
count++;

if (count < EARLY_FAIL_ENHANCE_MAX)
continue;
}

break;
/* Cannot be part of a repeat. */
common->private_data_ptrs[begin - common->start] = 1;

if (count >= EARLY_FAIL_ENHANCE_MAX)
break;
}

if (*cc != OP_ALT && *cc != OP_KET)
Expand Down Expand Up @@ -14239,7 +14282,7 @@ memset(common->private_data_ptrs, 0, total_length * sizeof(sljit_s32));
private_data_size = common->cbra_ptr + (re->top_bracket + 1) * sizeof(sljit_sw);

if ((re->overall_options & PCRE2_ANCHORED) == 0 && (re->overall_options & PCRE2_NO_START_OPTIMIZE) == 0 && !common->has_skip_in_assert_back)
detect_early_fail(common, common->start, &private_data_size, 0, 0, TRUE);
detect_early_fail(common, common->start, &private_data_size, 0, 0);

set_private_data_ptrs(common, &private_data_size, ccend);

Expand Down
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