// Copyright 2019 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "irregexp/imported/regexp-ast-printer.h"
#include "irregexp/imported/regexp-compiler.h"
#include "irregexp/imported/regexp-graph-printer.h"
#include "irregexp/imported/regexp.h"
#ifdef V8_INTL_SUPPORT
#include "irregexp/imported/special-case.h"
#include "unicode/locid.h"
#include "unicode/uniset.h"
#include "unicode/utypes.h"
#endif // V8_INTL_SUPPORT
namespace v8 {
namespace internal {
namespace regexp {
using namespace compiler_constants;
// NOLINT(build/namespaces)
constexpr base::uc32 kMaxCodePoint =
0x10ffff;
constexpr
int kMaxUtf16CodeUnit =
0xffff;
constexpr uint32_t kMaxUtf16CodeUnitU =
0xffff;
#ifdef V8_ENABLE_REGEXP_DIAGNOSTICS
#define TRACE(msg) \
do { \
if (V8_UNLIKELY(v8_flags.trace_regexp_graph_building)) { \
std::ostream& os = compiler->diagnostics()->trace_tree_scope()->os(); \
os << msg << std::endl; \
} \
}
while (
false)
#define TRACE_WITH_NODE(msg, node) \
do { \
if (V8_UNLIKELY(v8_flags.trace_regexp_graph_building)) { \
std::ostream& os = compiler->diagnostics()->trace_tree_scope()->os(); \
os << msg; \
compiler->diagnostics()->ast_printer()->Print(node); \
os << std::endl; \
} \
}
while (
false)
#define REGISTER_NODE(node) \
do { \
if (V8_UNLIKELY(!!compiler->diagnostics() && \
compiler->diagnostics()->has_graph_labeller())) { \
compiler->diagnostics()->graph_labeller()->RegisterNode(node); \
} \
if (V8_UNLIKELY(v8_flags.trace_regexp_graph_building)) { \
compiler->diagnostics()->trace_tree_scope()->os() <<
"+ "; \
compiler->diagnostics()->graph_printer()->PrintNode(node); \
} \
}
while (
false)
#else
#define TRACE(msg) (
void(
0))
#define TRACE_WITH_NODE(msg, node) (
void(
0))
#define REGISTER_NODE(node) (
void(
0))
#endif
// -------------------------------------------------------------------
// Tree to graph conversion
Node* Tree::ToNode(Compiler* compiler, Node* on_success) {
#ifdef V8_ENABLE_REGEXP_DIAGNOSTICS
TraceTreeScope trace_tree_scope(compiler->diagnostics());
if (V8_UNLIKELY(v8_flags.trace_regexp_graph_building)) {
trace_tree_scope.PrintTree(
this);
}
#endif
// We try to remove entire subbranches of the node structure that can't
// succeed by returning backtrack nodes instead of nodes that first match
// something and then inevitably backtrack.
if (on_success->IsBacktrack())
return on_success;
compiler->ToNodeMaybeCheckForStackOverflow();
if (compiler->IsRegExpTooBig()) {
// We can always return this even though it may not be the expected
// subclass because all call sites already have to check for this case.
Zone* zone = compiler->zone();
return zone->
New<EndNode>(EndNode::BACKTRACK, zone);
}
return ToNodeImpl(compiler, on_success);
}
Node* Atom::ToNodeImpl(Compiler* compiler, Node* on_success) {
Zone* zone = compiler->zone();
ZoneList<TextElement>* elms = zone->
New<ZoneList<TextElement>>(
1, zone);
elms->Add(TextElement::FromAtom(
this), zone);
TextNode* result =
zone->
New<TextNode>(elms, compiler->read_backward(), on_success);
if (compiler->one_byte() && !result->CanMatchLatin1(compiler)) {
Node* backtrack = zone->
New<EndNode>(EndNode::BACKTRACK, zone);
REGISTER_NODE(backtrack);
return backtrack;
}
REGISTER_NODE(result);
return result;
}
Node* Text::ToNodeImpl(Compiler* compiler, Node* on_success) {
Zone* zone = compiler->zone();
TextNode* result =
zone->
New<TextNode>(elements(), compiler->read_backward(), on_success);
if (compiler->one_byte() && !result->CanMatchLatin1(compiler)) {
Node* backtrack = zone->
New<EndNode>(EndNode::BACKTRACK, zone);
REGISTER_NODE(backtrack);
return backtrack;
}
REGISTER_NODE(result);
return result;
}
namespace {
bool CompareInverseRanges(ZoneList<CharacterRange>* ranges,
const int* special_class,
int length) {
length--;
// Remove final marker.
DCHECK_EQ(kRangeEndMarker, special_class[length]);
DCHECK_NE(
0, ranges->length());
DCHECK_NE(
0, length);
DCHECK_NE(
0, special_class[
0]);
if (ranges->length() != (length >>
1) +
1)
return false;
CharacterRange range = ranges->at(
0);
if (range.from() !=
0)
return false;
for (
int i =
0; i < length; i +=
2) {
if (
static_cast<base::uc32>(special_class[i]) != (range.to() +
1)) {
return false;
}
range = ranges->at((i >>
1) +
1);
if (
static_cast<base::uc32>(special_class[i +
1]) != range.from()) {
return false;
}
}
return range.to() == kMaxCodePoint;
}
bool CompareRanges(ZoneList<CharacterRange>* ranges,
const int* special_class,
int length) {
length--;
// Remove final marker.
DCHECK_EQ(kRangeEndMarker, special_class[length]);
if (ranges->length() *
2 != length)
return false;
for (
int i =
0; i < length; i +=
2) {
CharacterRange range = ranges->at(i >>
1);
if (range.from() !=
static_cast<base::uc32>(special_class[i]) ||
range.to() !=
static_cast<base::uc32>(special_class[i +
1] -
1)) {
return false;
}
}
return true;
}
}
// namespace
bool ClassRanges::is_standard(Zone* zone) {
// TODO(lrn): Remove need for this function, by not throwing away information
// along the way.
if (is_negated()) {
return false;
}
if (set_.is_standard()) {
return true;
}
if (CompareRanges(set_.ranges(zone), kSpaceRanges, kSpaceRangeCount)) {
set_.set_standard_set_type(StandardCharacterSet::kWhitespace);
return true;
}
if (CompareInverseRanges(set_.ranges(zone), kSpaceRanges, kSpaceRangeCount)) {
set_.set_standard_set_type(StandardCharacterSet::kNotWhitespace);
return true;
}
if (CompareInverseRanges(set_.ranges(zone), kLineTerminatorRanges,
kLineTerminatorRangeCount)) {
set_.set_standard_set_type(StandardCharacterSet::kNotLineTerminator);
return true;
}
if (CompareRanges(set_.ranges(zone), kLineTerminatorRanges,
kLineTerminatorRangeCount)) {
set_.set_standard_set_type(StandardCharacterSet::kLineTerminator);
return true;
}
if (CompareRanges(set_.ranges(zone), kWordRanges, kWordRangeCount)) {
set_.set_standard_set_type(StandardCharacterSet::kWord);
return true;
}
if (CompareInverseRanges(set_.ranges(zone), kWordRanges, kWordRangeCount)) {
set_.set_standard_set_type(StandardCharacterSet::kNotWord);
return true;
}
return false;
}
UnicodeRangeSplitter::UnicodeRangeSplitter(ZoneList<CharacterRange>* base) {
// The unicode range splitter categorizes given character ranges into:
// - Code points from the BMP representable by one code unit.
// - Code points outside the BMP that need to be split into
// surrogate pairs.
// - Lone lead surrogates.
// - Lone trail surrogates.
// Lone surrogates are valid code points, even though no actual characters.
// They require special matching to make sure we do not split surrogate pairs.
for (
int i =
0; i < base->length(); i++) AddRange(base->at(i));
}
void UnicodeRangeSplitter::AddRange(CharacterRange range) {
static constexpr base::uc32 kBmp1Start =
0;
static constexpr base::uc32 kBmp1End = kLeadSurrogateStart -
1;
static constexpr base::uc32 kBmp2Start = kTrailSurrogateEnd +
1;
static constexpr base::uc32 kBmp2End = kNonBmpStart -
1;
// Ends are all inclusive.
static_assert(kBmp1Start ==
0);
static_assert(kBmp1Start < kBmp1End);
static_assert(kBmp1End +
1 == kLeadSurrogateStart);
static_assert(kLeadSurrogateStart < kLeadSurrogateEnd);
static_assert(kLeadSurrogateEnd +
1 == kTrailSurrogateStart);
static_assert(kTrailSurrogateStart < kTrailSurrogateEnd);
static_assert(kTrailSurrogateEnd +
1 == kBmp2Start);
static_assert(kBmp2Start < kBmp2End);
static_assert(kBmp2End +
1 == kNonBmpStart);
static_assert(kNonBmpStart < kNonBmpEnd);
static constexpr base::uc32 kStarts[] = {
kBmp1Start, kLeadSurrogateStart, kTrailSurrogateStart,
kBmp2Start, kNonBmpStart,
};
static constexpr base::uc32 kEnds[] = {
kBmp1End, kLeadSurrogateEnd, kTrailSurrogateEnd, kBmp2End, kNonBmpEnd,
};
CharacterRangeVector*
const kTargets[] = {
&bmp_, &lead_surrogates_, &trail_surrogates_, &bmp_, &non_bmp_,
};
static constexpr
int kCount = arraysize(kStarts);
static_assert(kCount == arraysize(kEnds));
static_assert(kCount == arraysize(kTargets));
for (
int i =
0; i < kCount; i++) {
if (kStarts[i] > range.to())
break;
const base::uc32 from = std::max(kStarts[i], range.from());
const base::uc32 to = std::min(kEnds[i], range.to());
if (from > to)
continue;
kTargets[i]->emplace_back(CharacterRange::Range(from, to));
}
}
namespace {
// Translates between new and old V8-isms (SmallVector, ZoneList).
ZoneList<CharacterRange>* ToCanonicalZoneList(
const UnicodeRangeSplitter::CharacterRangeVector* v, Zone* zone) {
if (v->empty())
return nullptr;
ZoneList<CharacterRange>* result =
zone->
New<ZoneList<CharacterRange>>(
static_cast<
int>(v->size()), zone);
for (size_t i =
0; i < v->size(); i++) {
result->Add(v->at(i), zone);
}
CharacterRange::Canonicalize(result);
return result;
}
void AddBmpCharacters(Compiler* compiler, ChoiceNode* result, Node* on_success,
UnicodeRangeSplitter* splitter) {
TRACE(
"* Add BMP Characters");
ZoneList<CharacterRange>* bmp =
ToCanonicalZoneList(splitter->bmp(), compiler->zone());
if (bmp == nullptr)
return;
Node* node = TextNode::CreateForCharacterRanges(
compiler->zone(), bmp, compiler->read_backward(), on_success);
REGISTER_NODE(node);
result->AddAlternative(GuardedAlternative(node));
}
using UC16Range = uint32_t;
// {from, to} packed into one uint32_t.
constexpr UC16Range ToUC16Range(base::uc16 from, base::uc16 to) {
return (
static_cast<uint32_t>(from) <<
16) | to;
}
constexpr base::uc16 ExtractFrom(UC16Range r) {
return static_cast<base::uc16>(r >>
16);
}
constexpr base::uc16 ExtractTo(UC16Range r) {
return static_cast<base::uc16>(r);
}
void AddNonBmpSurrogatePairs(Compiler* compiler, ChoiceNode* result,
Node* on_success, UnicodeRangeSplitter* splitter) {
DCHECK(!compiler->one_byte());
Zone*
const zone = compiler->zone();
ZoneList<CharacterRange>* non_bmp =
ToCanonicalZoneList(splitter->non_bmp(), zone);
if (non_bmp == nullptr)
return;
// Translate each 32-bit code point range into the corresponding 16-bit code
// unit representation consisting of the lead- and trail surrogate.
//
// The generated alternatives are grouped by the leading surrogate to avoid
// emitting excessive code. For example, for
//
// { \ud800[\udc00-\udc01]
// , \ud800[\udc05-\udc06]
// }
//
// there's no need to emit matching code for the leading surrogate \ud800
// twice. We also create a dedicated grouping for full trailing ranges, i.e.
// [dc00-dfff].
TRACE(
"* Add Non-BMP Surrogate Pairs");
ZoneUnorderedMap<UC16Range, ZoneList<CharacterRange>*> grouped_by_leading(
zone);
ZoneList<CharacterRange>* leading_with_full_trailing_range =
zone->
New<ZoneList<CharacterRange>>(
1, zone);
const auto AddRange = [&](base::uc16 from_l, base::uc16 to_l,
base::uc16 from_t, base::uc16 to_t) {
const UC16Range leading_range = ToUC16Range(from_l, to_l);
if (grouped_by_leading.count(leading_range) ==
0) {
if (from_t == kTrailSurrogateStart && to_t == kTrailSurrogateEnd) {
leading_with_full_trailing_range->Add(
CharacterRange::Range(from_l, to_l), zone);
return;
}
grouped_by_leading[leading_range] =
zone->
New<ZoneList<CharacterRange>>(
2, zone);
}
grouped_by_leading[leading_range]->Add(CharacterRange::Range(from_t, to_t),
zone);
};
// First, create the grouped ranges.
CharacterRange::Canonicalize(non_bmp);
for (
int i =
0; i < non_bmp->length(); i++) {
// Match surrogate pair.
// E.g. [\u10005-\u11005] becomes
// \ud800[\udc05-\udfff]|
// [\ud801-\ud803][\udc00-\udfff]|
// \ud804[\udc00-\udc05]
base::uc32 from = non_bmp->at(i).from();
base::uc32 to = non_bmp->at(i).to();
base::uc16 from_l = unibrow::Utf16::LeadSurrogate(from);
base::uc16 from_t = unibrow::Utf16::TrailSurrogate(from);
base::uc16 to_l = unibrow::Utf16::LeadSurrogate(to);
base::uc16 to_t = unibrow::Utf16::TrailSurrogate(to);
if (from_l == to_l) {
// The lead surrogate is the same.
AddRange(from_l, to_l, from_t, to_t);
continue;
}
if (from_t != kTrailSurrogateStart) {
// Add [from_l][from_t-\udfff].
AddRange(from_l, from_l, from_t, kTrailSurrogateEnd);
from_l++;
}
if (to_t != kTrailSurrogateEnd) {
// Add [to_l][\udc00-to_t].
AddRange(to_l, to_l, kTrailSurrogateStart, to_t);
to_l--;
}
if (from_l <= to_l) {
// Add [from_l-to_l][\udc00-\udfff].
AddRange(from_l, to_l, kTrailSurrogateStart, kTrailSurrogateEnd);
}
}
// Create the actual TextNode now that ranges are fully grouped.
if (!leading_with_full_trailing_range->is_empty()) {
CharacterRange::Canonicalize(leading_with_full_trailing_range);
Node* node = TextNode::CreateForSurrogatePair(
zone, leading_with_full_trailing_range,
CharacterRange::Range(kTrailSurrogateStart, kTrailSurrogateEnd),
compiler->read_backward(), on_success);
REGISTER_NODE(node);
result->AddAlternative(GuardedAlternative(node));
}
for (
const auto& it : grouped_by_leading) {
CharacterRange leading_range =
CharacterRange::Range(ExtractFrom(it.first), ExtractTo(it.first));
ZoneList<CharacterRange>* trailing_ranges = it.second;
CharacterRange::Canonicalize(trailing_ranges);
Node* node =
TextNode::CreateForSurrogatePair(zone, leading_range, trailing_ranges,
compiler->read_backward(), on_success);
REGISTER_NODE(node);
result->AddAlternative(GuardedAlternative(node));
}
}
Node* NegativeLookaroundAgainstReadDirectionAndMatch(
Compiler* compiler, ZoneList<CharacterRange>* lookbehind,
ZoneList<CharacterRange>* match, Node* on_success,
bool read_backward) {
Zone* zone = compiler->zone();
Node* match_node = TextNode::CreateForCharacterRanges(
zone, match, read_backward, on_success);
REGISTER_NODE(match_node);
int stack_register = compiler->UnicodeLookaroundStackRegister();
int position_register = compiler->UnicodeLookaroundPositionRegister();
Lookaround::Builder lookaround(
false, match_node, compiler, stack_register,
position_register);
Node* negative_match = TextNode::CreateForCharacterRanges(
zone, lookbehind, !read_backward, lookaround.on_match_success());
REGISTER_NODE(negative_match);
return lookaround.ForMatch(compiler, negative_match);
}
Node* MatchAndNegativeLookaroundInReadDirection(
Compiler* compiler, ZoneList<CharacterRange>* match,
ZoneList<CharacterRange>* lookahead, Node* on_success,
bool read_backward) {
Zone* zone = compiler->zone();
int stack_register = compiler->UnicodeLookaroundStackRegister();
int position_register = compiler->UnicodeLookaroundPositionRegister();
Lookaround::Builder lookaround(
false, on_success, compiler, stack_register,
position_register);
Node* negative_match = TextNode::CreateForCharacterRanges(
zone, lookahead, read_backward, lookaround.on_match_success());
REGISTER_NODE(negative_match);
Node* node = TextNode::CreateForCharacterRanges(
zone, match, read_backward,
lookaround.ForMatch(compiler, negative_match));
REGISTER_NODE(node);
return node;
}
void AddLoneLeadSurrogates(Compiler* compiler, ChoiceNode* result,
Node* on_success, UnicodeRangeSplitter* splitter) {
ZoneList<CharacterRange>* lead_surrogates =
ToCanonicalZoneList(splitter->lead_surrogates(), compiler->zone());
if (lead_surrogates == nullptr)
return;
TRACE(
"* Add Lone Lead Surrogates");
Zone* zone = compiler->zone();
// E.g. \ud801 becomes \ud801(?![\udc00-\udfff]).
ZoneList<CharacterRange>* trail_surrogates = CharacterRange::List(
zone, CharacterRange::Range(kTrailSurrogateStart, kTrailSurrogateEnd));
Node* match;
if (compiler->read_backward()) {
// Reading backward. Assert that reading forward, there is no trail
// surrogate, and then backward match the lead surrogate.
match = NegativeLookaroundAgainstReadDirectionAndMatch(
compiler, trail_surrogates, lead_surrogates, on_success,
true);
}
else {
// Reading forward. Forward match the lead surrogate and assert that
// no trail surrogate follows.
match = MatchAndNegativeLookaroundInReadDirection(
compiler, lead_surrogates, trail_surrogates, on_success,
false);
}
result->AddAlternative(GuardedAlternative(match));
}
void AddLoneTrailSurrogates(Compiler* compiler, ChoiceNode* result,
Node* on_success, UnicodeRangeSplitter* splitter) {
ZoneList<CharacterRange>* trail_surrogates =
ToCanonicalZoneList(splitter->trail_surrogates(), compiler->zone());
if (trail_surrogates == nullptr)
return;
TRACE(
"* Add Lone Trail Surrogates");
Zone* zone = compiler->zone();
// E.g. \udc01 becomes (?<![\ud800-\udbff])\udc01
ZoneList<CharacterRange>* lead_surrogates = CharacterRange::List(
zone, CharacterRange::Range(kLeadSurrogateStart, kLeadSurrogateEnd));
Node* match;
if (compiler->read_backward()) {
// Reading backward. Backward match the trail surrogate and assert that no
// lead surrogate precedes it.
match = MatchAndNegativeLookaroundInReadDirection(
compiler, trail_surrogates, lead_surrogates, on_success,
true);
}
else {
// Reading forward. Assert that reading backward, there is no lead
// surrogate, and then forward match the trail surrogate.
match = NegativeLookaroundAgainstReadDirectionAndMatch(
compiler, lead_surrogates, trail_surrogates, on_success,
false);
}
result->AddAlternative(GuardedAlternative(match));
}
Node* UnanchoredAdvance(Compiler* compiler, Node* on_success) {
// This implements ES2015 21.2.5.2.3, AdvanceStringIndex.
DCHECK(!compiler->read_backward());
Node* node = compiler->zone()->
New<UnanchoredAdvanceNode>(on_success);
REGISTER_NODE(node);
return node;
}
}
// namespace
// static
// Only for /ui and /vi, not for /i regexps.
void CharacterRange::AddUnicodeCaseEquivalents(ZoneList<CharacterRange>* ranges,
Zone* zone) {
#ifdef V8_INTL_SUPPORT
DCHECK(IsCanonical(ranges));
// Micro-optimization to avoid passing large ranges to UnicodeSet::closeOver.
// See also https://crbug.com/v8/6727.
// TODO(jgruber): This only covers the special case of the {0,0x10FFFF} range,
// which we use frequently internally. But large ranges can also easily be
// created by the user. We might want to have a more general caching mechanism
// for such ranges.
if (ranges->length() ==
1 && ranges->at(
0).IsEverything(kNonBmpEnd))
return;
// Use ICU to compute the case fold closure over the ranges.
icu::UnicodeSet set;
for (
int i =
0; i < ranges->length(); i++) {
set.add(ranges->at(i).from(), ranges->at(i).to());
}
// Clear the ranges list without freeing the backing store.
ranges->Rewind(
0);
set.closeOver(USET_SIMPLE_CASE_INSENSITIVE);
for (
int i =
0; i < set.getRangeCount(); i++) {
ranges->Add(Range(set.getRangeStart(i), set.getRangeEnd(i)), zone);
}
// No errors and everything we collected have been ranges.
Canonicalize(ranges);
#endif // V8_INTL_SUPPORT
}
Node* ClassRanges::ToNodeImpl(Compiler* compiler, Node* on_success) {
set_.Canonicalize();
TRACE_WITH_NODE(
"* After canonicalization: ",
this);
Zone*
const zone = compiler->zone();
ZoneList<CharacterRange>* ranges =
this->ranges(zone);
const bool needs_case_folding =
NeedsUnicodeCaseEquivalents(compiler->flags()) &&
!no_case_folding_needed();
if (needs_case_folding) {
CharacterRange::AddUnicodeCaseEquivalents(ranges, zone);
TRACE_WITH_NODE(
"* After case folding: ",
this);
}
if (!IsEitherUnicode(compiler->flags()) || compiler->one_byte() ||
contains_split_surrogate()) {
TextNode* result =
zone->
New<TextNode>(
this, compiler->read_backward(), on_success);
if (compiler->one_byte() && !result->CanMatchLatin1(compiler)) {
Node* backtrack = zone->
New<EndNode>(EndNode::BACKTRACK, zone);
REGISTER_NODE(backtrack);
return backtrack;
}
REGISTER_NODE(result);
return result;
}
if (is_negated()) {
// With /v, character classes are never negated.
// https://tc39.es/ecma262/#sec-compileatom
// Atom :: CharacterClass
// 4. Assert: cc.[[Invert]] is false.
// Instead the complement is created when evaluating the class set.
// The only exception is the "nothing range" (negated everything), which is
// internally created for an empty set.
DCHECK_IMPLIES(
IsUnicodeSets(compiler->flags()),
ranges->length() ==
1 && ranges->first().IsEverything(kMaxCodePoint));
ZoneList<CharacterRange>* negated =
zone->
New<ZoneList<CharacterRange>>(
2, zone);
CharacterRange::Negate(ranges, negated, zone);
ranges = negated;
#ifdef V8_ENABLE_REGEXP_DIAGNOSTICS
if (V8_UNLIKELY(v8_flags.trace_regexp_graph_building)) {
std::ostream& os = compiler->diagnostics()->trace_tree_scope()->os();
os <<
"* After negation: [";
for (
int i =
0; i < ranges->length(); i++) {
const CharacterRange& range = ranges->at(i);
os <<
" " << AsUC32(range.from());
if (!range.IsSingleton()) {
os <<
"-" << AsUC32(range.to());
}
}
os <<
"]" << std::endl;
}
#endif
}
if (ranges->length() ==
0) {
Node* backtrack = zone->
New<EndNode>(EndNode::BACKTRACK, zone);
REGISTER_NODE(backtrack);
return backtrack;
}
if (set_.is_standard() &&
standard_type() == StandardCharacterSet::kEverything) {
return UnanchoredAdvance(compiler, on_success);
}
// Split ranges in order to handle surrogates correctly:
// - Surrogate pairs: translate the 32-bit code point into two uc16 code
// units (irregexp operates only on code units).
// - Lone surrogates: these require lookarounds to ensure we don't match in
// the middle of a surrogate pair.
ChoiceNode* result = zone->
New<ChoiceNode>(
2, zone);
UnicodeRangeSplitter splitter(ranges);
AddBmpCharacters(compiler, result, on_success, &splitter);
AddNonBmpSurrogatePairs(compiler, result, on_success, &splitter);
AddLoneLeadSurrogates(compiler, result, on_success, &splitter);
AddLoneTrailSurrogates(compiler, result, on_success, &splitter);
static constexpr
int kMaxRangesToInline =
32;
// Arbitrary.
if (ranges->length() > kMaxRangesToInline) result->SetDoNotInline();
if (result->alternatives()->length() ==
1) {
return result->alternatives()->at(
0).node();
}
REGISTER_NODE(result);
return result;
}
Node* ClassSetOperand::ToNodeImpl(Compiler* compiler, Node* on_success) {
Zone* zone = compiler->zone();
const int size = (has_strings() ?
static_cast<
int>(strings()->size()) :
0) +
(ranges()->is_empty() ?
0 :
1);
if (size ==
0) {
// If neither ranges nor strings are present, the operand is equal to an
// empty range (matching nothing).
Node* backtrack = zone->
New<EndNode>(EndNode::BACKTRACK, zone);
REGISTER_NODE(backtrack);
return backtrack;
}
ZoneList<Tree*>* alternatives = zone->
New<ZoneList<Tree*>>(size, zone);
// Strings are sorted by length first (larger strings before shorter ones).
// See the comment on CharacterClassStrings.
// Empty strings (if present) are added after character ranges.
Tree* empty_string = nullptr;
if (has_strings()) {
for (
auto string : *strings()) {
if (string.second->IsEmpty()) {
empty_string = string.second;
}
else {
alternatives->Add(string.second, zone);
}
}
}
if (!ranges()->is_empty()) {
// In unicode sets mode case folding has to be done at precise locations
// (e.g. before building complements).
// It is therefore the parsers responsibility to case fold (sub-) ranges
// before creating ClassSetOperands.
alternatives->Add(zone->
New<ClassRanges>(
zone, ranges(), ClassRanges::NO_CASE_FOLDING_NEEDED),
zone);
}
if (empty_string != nullptr) {
alternatives->Add(empty_string, zone);
}
Tree* tree = nullptr;
if (size ==
1) {
DCHECK_EQ(alternatives->length(),
1);
tree = alternatives->first();
}
else {
tree = zone->
New<Disjunction>(alternatives);
}
Node* node = tree->ToNode(compiler, on_success);
REGISTER_NODE(node);
return node;
}
Node* ClassSetExpression::ToNodeImpl(Compiler* compiler, Node* on_success) {
Zone* zone = compiler->zone();
ZoneList<CharacterRange>* temp_ranges =
zone->
New<ZoneList<CharacterRange>>(
4, zone);
ClassSetOperand* root = ComputeExpression(
this, temp_ranges, zone);
Node* node = root->ToNode(compiler, on_success);
REGISTER_NODE(node);
return node;
}
void ClassSetOperand::
Union(ClassSetOperand* other, Zone* zone) {
ranges()->AddAll(*other->ranges(), zone);
if (other->has_strings()) {
if (strings_ == nullptr) {
strings_ = zone->
New<CharacterClassStrings>(zone);
}
strings()->insert(other->strings()->begin(), other->strings()->end());
}
}
void ClassSetOperand::Intersect(ClassSetOperand* other,
ZoneList<CharacterRange>* temp_ranges,
Zone* zone) {
CharacterRange::Intersect(ranges(), other->ranges(), temp_ranges, zone);
std::swap(*ranges(), *temp_ranges);
temp_ranges->Rewind(
0);
if (has_strings()) {
if (!other->has_strings()) {
strings()->clear();
}
else {
for (
auto iter = strings()->begin(); iter != strings()->end();) {
if (other->strings()->find(iter->first) == other->strings()->end()) {
iter = strings()->erase(iter);
}
else {
iter++;
}
}
}
}
}
void ClassSetOperand::Subtract(ClassSetOperand* other,
ZoneList<CharacterRange>* temp_ranges,
Zone* zone) {
CharacterRange::Subtract(ranges(), other->ranges(), temp_ranges, zone);
std::swap(*ranges(), *temp_ranges);
temp_ranges->Rewind(
0);
if (has_strings() && other->has_strings()) {
for (
auto iter = strings()->begin(); iter != strings()->end();) {
if (other->strings()->find(iter->first) != other->strings()->end()) {
iter = strings()->erase(iter);
}
else {
iter++;
}
}
}
}
// static
ClassSetOperand* ClassSetExpression::ComputeExpression(
Tree* root, ZoneList<CharacterRange>* temp_ranges, Zone* zone) {
DCHECK(temp_ranges->is_empty());
if (root->IsClassSetOperand()) {
return root->AsClassSetOperand();
}
DCHECK(root->IsClassSetExpression());
ClassSetExpression* node = root->AsClassSetExpression();
ClassSetOperand* result =
ComputeExpression(node->operands()->at(
0), temp_ranges, zone);
switch (node->operation()) {
case OperationType::kUnion: {
for (
int i =
1; i < node->operands()->length(); i++) {
ClassSetOperand* op =
ComputeExpression(node->operands()->at(i), temp_ranges, zone);
result->
Union(op, zone);
}
CharacterRange::Canonicalize(result->ranges());
break;
}
case OperationType::kIntersection: {
for (
int i =
1; i < node->operands()->length(); i++) {
ClassSetOperand* op =
ComputeExpression(node->operands()->at(i), temp_ranges, zone);
result->Intersect(op, temp_ranges, zone);
}
break;
}
case OperationType::kSubtraction: {
for (
int i =
1; i < node->operands()->length(); i++) {
ClassSetOperand* op =
ComputeExpression(node->operands()->at(i), temp_ranges, zone);
result->Subtract(op, temp_ranges, zone);
}
break;
}
}
if (node->is_negated()) {
DCHECK(!result->has_strings());
CharacterRange::Negate(result->ranges(), temp_ranges, zone);
std::swap(*result->ranges(), *temp_ranges);
temp_ranges->Rewind(
0);
node->is_negated_ =
false;
}
// Store the result as single operand of the current node.
node->operands()->Set(
0, result);
node->operands()->Rewind(
1);
return result;
}
namespace {
bool StartsWithAtom(Tree* tree) {
if (tree->IsAtom())
return true;
return tree->IsText() && tree->AsText()->StartsWithAtom();
}
Atom* FirstAtom(Tree* tree) {
if (tree->IsAtom())
return tree->AsAtom();
return tree->AsText()->FirstAtom();
}
int CompareFirstChar(Tree*
const* a, Tree*
const* b) {
Atom* atom1 = FirstAtom(*a);
Atom* atom2 = FirstAtom(*b);
base::uc16 character1 = atom1->data().at(
0);
base::uc16 character2 = atom2->data().at(
0);
if (character1 < character2)
return -
1;
if (character1 > character2)
return 1;
return 0;
}
#ifdef V8_INTL_SUPPORT
int CompareCaseInsensitive(
const icu::UnicodeString& a,
const icu::UnicodeString& b) {
return a.caseCompare(b, U_FOLD_CASE_DEFAULT);
}
int CompareFirstCharCaseInsensitive(Tree*
const* a, Tree*
const* b) {
Atom* atom1 = FirstAtom(*a);
Atom* atom2 = FirstAtom(*b);
return CompareCaseInsensitive(icu::UnicodeString{atom1->data().at(
0)},
icu::UnicodeString{atom2->data().at(
0)});
}
bool Equals(
bool ignore_case,
const icu::UnicodeString& a,
const icu::UnicodeString& b) {
if (a == b)
return true;
if (ignore_case)
return CompareCaseInsensitive(a, b) ==
0;
return false;
// Case-sensitive equality already checked above.
}
bool CharAtEquals(
bool ignore_case,
int index,
const Atom* a,
const Atom* b) {
return Equals(ignore_case, a->data().at(index), b->data().at(index));
}
#else
unibrow::uchar Canonical(
unibrow::Mapping<unibrow::Ecma262Canonicalize>* canonicalize,
unibrow::uchar c) {
unibrow::uchar chars[unibrow::Ecma262Canonicalize::kMaxWidth];
int length = canonicalize->get(c,
'\0', chars);
DCHECK_LE(length,
1);
unibrow::uchar canonical = c;
if (length ==
1) canonical = chars[
0];
return canonical;
}
int CompareCaseInsensitive(
unibrow::Mapping<unibrow::Ecma262Canonicalize>* canonicalize,
unibrow::uchar a, unibrow::uchar b) {
if (a == b)
return 0;
if (a >=
'a' || b >=
'a') {
a = Canonical(canonicalize, a);
b = Canonical(canonicalize, b);
}
return static_cast<
int>(a) -
static_cast<
int>(b);
}
int CompareFirstCharCaseInsensitive(
unibrow::Mapping<unibrow::Ecma262Canonicalize>* canonicalize,
Tree*
const* a, Tree*
const* b) {
Atom* atom1 = FirstAtom(*a);
Atom* atom2 = FirstAtom(*b);
return CompareCaseInsensitive(canonicalize, atom1->data().at(
0),
atom2->data().at(
0));
}
bool Equals(
bool ignore_case,
unibrow::Mapping<unibrow::Ecma262Canonicalize>* canonicalize,
unibrow::uchar a, unibrow::uchar b) {
if (a == b)
return true;
if (ignore_case) {
return CompareCaseInsensitive(canonicalize, a, b) ==
0;
}
return false;
// Case-sensitive equality already checked above.
}
bool CharAtEquals(
bool ignore_case,
unibrow::Mapping<unibrow::Ecma262Canonicalize>* canonicalize,
int index,
const Atom* a,
const Atom* b) {
return Equals(ignore_case, canonicalize, a->data().at(index),
b->data().at(index));
}
#endif // V8_INTL_SUPPORT
}
// namespace
// We can stable sort runs of atoms, since the order does not matter if they
// start with different characters.
// Returns true if any consecutive atoms were found.
bool Disjunction::SortConsecutiveAtoms(Compiler* compiler) {
ZoneList<Tree*>* alternatives =
this->alternatives();
int length = alternatives->length();
bool found_consecutive_atoms =
false;
for (
int i =
0; i < length; i++) {
while (i < length) {
Tree* alternative = alternatives->at(i);
if (StartsWithAtom(alternative))
break;
i++;
}
// i is length or it is the index of an atom.
if (i == length)
break;
int first_atom = i;
i++;
while (i < length) {
Tree* alternative = alternatives->at(i);
if (!StartsWithAtom(alternative))
break;
i++;
}
// Sort atoms to get ones with common prefixes together.
// This step is more tricky if we are in a case-independent regexp,
// because it would change /is|I/ to /I|is/, and order matters when
// the regexp parts don't match only disjoint starting points. To fix
// this we have a version of CompareFirstChar that uses case-
// independent character classes for comparison.
DCHECK_LT(first_atom, alternatives->length());
DCHECK_LE(i, alternatives->length());
DCHECK_LE(first_atom, i);
if (IsIgnoreCase(compiler->flags())) {
#ifdef V8_INTL_SUPPORT
alternatives->StableSort(CompareFirstCharCaseInsensitive, first_atom,
i - first_atom);
#else
unibrow::Mapping<unibrow::Ecma262Canonicalize>* canonicalize =
compiler->isolate()->regexp_macro_assembler_canonicalize();
auto compare_closure = [canonicalize](Tree*
const* a, Tree*
const* b) {
return CompareFirstCharCaseInsensitive(canonicalize, a, b);
};
alternatives->StableSort(compare_closure, first_atom, i - first_atom);
#endif // V8_INTL_SUPPORT
}
else {
alternatives->StableSort(CompareFirstChar, first_atom, i - first_atom);
}
if (i - first_atom >
1) found_consecutive_atoms =
true;
}
return found_consecutive_atoms;
}
// Optimizes ab|ac|az to a(?:b|c|d).
void Disjunction::RationalizeConsecutiveAtoms(Compiler* compiler) {
Zone* zone = compiler->zone();
ZoneList<Tree*>* alternatives =
this->alternatives();
int length = alternatives->length();
const bool ignore_case = IsIgnoreCase(compiler->flags());
int write_posn =
0;
int i =
0;
while (i < length) {
Tree* alternative = alternatives->at(i);
if (!StartsWithAtom(alternative)) {
alternatives->at(write_posn++) = alternatives->at(i);
i++;
continue;
}
Atom*
const atom = FirstAtom(alternative);
#ifdef V8_INTL_SUPPORT
icu::UnicodeString common_prefix(atom->data().at(
0));
#else
unibrow::Mapping<unibrow::Ecma262Canonicalize>*
const canonicalize =
compiler->isolate()->regexp_macro_assembler_canonicalize();
unibrow::uchar common_prefix = atom->data().at(
0);
if (ignore_case) {
common_prefix = Canonical(canonicalize, common_prefix);
}
#endif // V8_INTL_SUPPORT
int first_with_prefix = i;
int prefix_length = atom->length();
i++;
while (i < length) {
alternative = alternatives->at(i);
if (!StartsWithAtom(alternative))
break;
Atom*
const alt_atom = FirstAtom(alternative);
#ifdef V8_INTL_SUPPORT
icu::UnicodeString new_prefix(alt_atom->data().at(
0));
if (!Equals(ignore_case, new_prefix, common_prefix))
break;
#else
unibrow::uchar new_prefix = alt_atom->data().at(
0);
if (!Equals(ignore_case, canonicalize, new_prefix, common_prefix))
break;
#endif // V8_INTL_SUPPORT
prefix_length = std::min(prefix_length, alt_atom->length());
i++;
}
if (i > first_with_prefix +
2) {
// Found worthwhile run of alternatives with common prefix of at least one
// character. The sorting function above did not sort on more than one
// character for reasons of correctness, but there may still be a longer
// common prefix if the terms were similar or presorted in the input.
// Find out how long the common prefix is.
int run_length = i - first_with_prefix;
Atom*
const alt_atom = FirstAtom(alternatives->at(first_with_prefix));
alternatives->at(first_with_prefix)->AsAtom();
for (
int j =
1; j < run_length && prefix_length >
1; j++) {
Atom* old_atom = FirstAtom(alternatives->at(j + first_with_prefix));
for (
int k =
1; k < prefix_length; k++) {
#ifdef V8_INTL_SUPPORT
if (!CharAtEquals(ignore_case, k, alt_atom, old_atom)) {
#else
if (!CharAtEquals(ignore_case, canonicalize, k, alt_atom, old_atom)) {
#endif // V8_INTL_SUPPORT
prefix_length = k;
break;
}
}
}
Atom* prefix =
zone->
New<Atom>(alt_atom->data().SubVector(
0, prefix_length));
TRACE_WITH_NODE(
"* Found common prefix: ", prefix);
ZoneList<Tree*>* pair = zone->
New<ZoneList<Tree*>>(
2, zone);
pair->Add(prefix, zone);
ZoneList<Tree*>* suffixes = zone->
New<ZoneList<Tree*>>(run_length, zone);
for (
int j =
0; j < run_length; j++) {
if (alternatives->at(j + first_with_prefix)->IsAtom()) {
Atom* old_atom = alternatives->at(j + first_with_prefix)->AsAtom();
int len = old_atom->length();
if (len == prefix_length) {
suffixes->Add(zone->
New<Empty>(), zone);
}
else {
Tree* suffix =
zone->
New<Atom>(old_atom->data().SubVector(prefix_length, len));
suffixes->Add(suffix, zone);
}
}
else {
Text* new_text = zone->
New<Text>(zone);
Text* old_text = alternatives->at(j + first_with_prefix)->AsText();
Atom* old_atom = old_text->FirstAtom();
int len = old_atom->length();
if (len != prefix_length) {
Atom* suffix =
zone->
New<Atom>(old_atom->data().SubVector(prefix_length, len));
new_text->AddElement(TextElement::FromAtom(suffix), zone);
}
for (
int k =
1; k < old_text->elements()->length(); k++) {
new_text->AddElement(old_text->elements()->at(k), zone);
}
if (new_text->elements()->length() !=
0) {
suffixes->Add(new_text, zone);
}
else {
suffixes->Add(zone->
New<Empty>(), zone);
}
}
}
pair->Add(zone->
New<Disjunction>(suffixes), zone);
alternatives->at(write_posn++) = zone->
New<Alternative>(pair);
}
else {
// Just copy any non-worthwhile alternatives.
for (
int j = first_with_prefix; j < i; j++) {
alternatives->at(write_posn++) = alternatives->at(j);
}
}
}
alternatives->Rewind(write_posn);
// Trim end of array.
}
// Optimizes b|c|z to [bcz].
void Disjunction::FixSingleCharacterDisjunctions(Compiler* compiler) {
Zone* zone = compiler->zone();
ZoneList<Tree*>* alternatives =
this->alternatives();
int length = alternatives->length();
int write_posn =
0;
int i =
0;
while (i < length) {
Tree* alternative = alternatives->at(i);
if (!alternative->IsAtom()) {
alternatives->at(write_posn++) = alternatives->at(i);
i++;
continue;
}
Atom*
const atom = alternative->AsAtom();
if (atom->length() !=
1) {
alternatives->at(write_posn++) = alternatives->at(i);
i++;
continue;
}
const Flags flags = compiler->flags();
DCHECK_IMPLIES(IsEitherUnicode(flags),
!unibrow::Utf16::IsLeadSurrogate(atom->data().at(
0)));
bool contains_trail_surrogate =
unibrow::Utf16::IsTrailSurrogate(atom->data().at(
0));
int first_in_run = i;
i++;
// Find a run of single-character atom alternatives that have identical
// flags (case independence and unicode-ness).
while (i < length) {
alternative = alternatives->at(i);
if (!alternative->IsAtom())
break;
Atom*
const alt_atom = alternative->AsAtom();
if (alt_atom->length() !=
1)
break;
DCHECK_IMPLIES(IsEitherUnicode(flags),
!unibrow::Utf16::IsLeadSurrogate(alt_atom->data().at(
0)));
contains_trail_surrogate |=
unibrow::Utf16::IsTrailSurrogate(alt_atom->data().at(
0));
i++;
}
if (i > first_in_run +
1) {
// Found non-trivial run of single-character alternatives.
int run_length = i - first_in_run;
ZoneList<CharacterRange>* ranges =
zone->
New<ZoneList<CharacterRange>>(
2, zone);
for (
int j =
0; j < run_length; j++) {
Atom* old_atom = alternatives->at(j + first_in_run)->AsAtom();
DCHECK_EQ(old_atom->length(),
1);
ranges->Add(CharacterRange::Singleton(old_atom->data().at(
0)), zone);
}
ClassRanges::ClassRangesFlags class_ranges_flags;
if (IsEitherUnicode(flags) && contains_trail_surrogate) {
class_ranges_flags = ClassRanges::CONTAINS_SPLIT_SURROGATE;
}
alternatives->at(write_posn++) =
zone->
New<ClassRanges>(zone, ranges, class_ranges_flags);
}
else {
// Just copy any trivial alternatives.
for (
int j = first_in_run; j < i; j++) {
alternatives->at(write_posn++) = alternatives->at(j);
}
}
}
alternatives->Rewind(write_posn);
// Trim end of array.
}
Node* Disjunction::ToNodeImpl(Compiler* compiler, Node* on_success) {
ZoneList<Tree*>* alternatives =
this->alternatives();
if (alternatives->length() >
2) {
bool found_consecutive_atoms = SortConsecutiveAtoms(compiler);
if (found_consecutive_atoms) RationalizeConsecutiveAtoms(compiler);
TRACE_WITH_NODE(
"* After rationalizing consecutive atoms: ",
this);
FixSingleCharacterDisjunctions(compiler);
TRACE_WITH_NODE(
"* After fixing single character disjunctions: ",
this);
if (alternatives->length() ==
1) {
return alternatives->at(
0)->ToNode(compiler, on_success);
}
}
int length = alternatives->length();
ChoiceNode* result =
compiler->zone()->
New<ChoiceNode>(length, compiler->zone());
for (
int i =
0; i < length; i++) {
GuardedAlternative alternative(
alternatives->at(i)->ToNode(compiler, on_success));
if (!alternative.node()->IsBacktrack()) {
result->AddAlternative(alternative);
}
}
REGISTER_NODE(result);
int node_length = result->alternatives()->length();
if (node_length >=
2)
return result;
if (node_length ==
1)
return result->alternatives()->at(
0).node();
Zone* zone = on_success->zone();
Node* backtrack = zone->
New<EndNode>(EndNode::BACKTRACK, zone);
REGISTER_NODE(backtrack);
return backtrack;
}
Node* Quantifier::ToNodeImpl(Compiler* compiler, Node* on_success) {
return ToNode(min(), max(), is_greedy(), body(), compiler, on_success);
}
namespace {
// Desugar \b to (?<=\w)(?=\W)|(?<=\W)(?=\w) and
// \B to (?<=\w)(?=\w)|(?<=\W)(?=\W)
Node* BoundaryAssertionAsLookaround(Compiler* compiler, Node* on_success,
Assertion::Type type) {
CHECK(NeedsUnicodeCaseEquivalents(compiler->flags()));
Zone* zone = compiler->zone();
ZoneList<CharacterRange>* word_range =
zone->
New<ZoneList<CharacterRange>>(
2, zone);
CharacterRange::AddClassEscape(StandardCharacterSet::kWord, word_range,
true,
zone);
int stack_register = compiler->UnicodeLookaroundStackRegister();
int position_register = compiler->UnicodeLookaroundPositionRegister();
ChoiceNode* result = zone->
New<ChoiceNode>(
2, zone);
// Add two choices. The (non-)boundary could start with a word or
// a non-word-character.
for (
int i =
0; i <
2; i++) {
bool lookbehind_for_word = i ==
0;
TRACE(
"* Creating " << (lookbehind_for_word ?
"lookbehind" :
"lookahead")
<<
" for word boundary");
bool lookahead_for_word =
(type == Assertion::Type::BOUNDARY) ^ lookbehind_for_word;
// Look to the left.
Lookaround::Builder lookbehind(lookbehind_for_word, on_success, compiler,
stack_register, position_register);
Node* backward = TextNode::CreateForCharacterRanges(
zone, word_range,
true, lookbehind.on_match_success());
REGISTER_NODE(backward);
// Look to the right.
Lookaround::Builder lookahead(lookahead_for_word,
lookbehind.ForMatch(compiler, backward),
compiler, stack_register, position_register);
Node* forward = TextNode::CreateForCharacterRanges(
zone, word_range,
false, lookahead.on_match_success());
REGISTER_NODE(forward);
result->AddAlternative(
GuardedAlternative(lookahead.ForMatch(compiler, forward)));
}
REGISTER_NODE(result);
return result;
}
}
// anonymous namespace
Node* Assertion::ToNodeImpl(Compiler* compiler, Node* on_success) {
NodeInfo info;
Zone* zone = compiler->zone();
switch (assertion_type()) {
case Type::START_OF_LINE: {
Node* node = AssertionNode::AfterNewline(on_success);
REGISTER_NODE(node);
return node;
}
case Type::START_OF_INPUT: {
Node* node = AssertionNode::AtStart(on_success);
REGISTER_NODE(node);
return node;
}
case Type::BOUNDARY: {
Node* node = NeedsUnicodeCaseEquivalents(compiler->flags())
? BoundaryAssertionAsLookaround(compiler, on_success,
Type::BOUNDARY)
: AssertionNode::AtBoundary(on_success);
REGISTER_NODE(node);
return node;
}
case Type::NON_BOUNDARY: {
Node* node = NeedsUnicodeCaseEquivalents(compiler->flags())
? BoundaryAssertionAsLookaround(compiler, on_success,
Type::NON_BOUNDARY)
: AssertionNode::AtNonBoundary(on_success);
REGISTER_NODE(node);
return node;
}
case Type::END_OF_INPUT: {
Node* node = AssertionNode::AtEnd(on_success);
REGISTER_NODE(node);
return node;
}
case Type::END_OF_BUFFER: {
// \Z matches at end-of-input, OR end-of-input preceded by a single
// line terminator, OR end-of-input preceded by a trailing \r\n.
// Desugar as:
// (?: (?:\r\n | [LF CR LS PS]) AT_END ) | AT_END
// wrapped so that the inner consumption is a positive lookahead
// (state is restored on success). The CRLF alternative is listed
// first so that a trailing "\r\n" takes the two-char branch
// without first trying the single-char branch and backtracking.
int stack_pointer_register = compiler->AllocateRegister();
int position_register = compiler->AllocateRegister();
Lookaround::Builder lookahead(
true, on_success, compiler,
stack_pointer_register, position_register);
Node* submatch_success = lookahead.on_match_success();
// Alt A: \r\n atom then AT_END (inside the lookahead).
static constexpr base::uc16 kCrlf[] = {
'\r',
'\n'};
Atom* crlf_atom =
zone->
New<Atom>(zone->CloneVector(base::ArrayVector(kCrlf)));
ZoneList<TextElement>* crlf_elms =
zone->
New<ZoneList<TextElement>>(
1, zone);
crlf_elms->Add(TextElement::FromAtom(crlf_atom), zone);
AssertionNode* crlf_at_end = AssertionNode::AtEnd(submatch_success);
REGISTER_NODE(crlf_at_end);
TextNode* crlf_matcher =
zone->
New<TextNode>(crlf_elms,
false, crlf_at_end);
REGISTER_NODE(crlf_matcher);
// Alt B: [LF CR LS PS] then AT_END.
ClassRanges* lt_atom =
zone->
New<ClassRanges>(StandardCharacterSet::kLineTerminator);
AssertionNode* lt_at_end = AssertionNode::AtEnd(submatch_success);
REGISTER_NODE(lt_at_end);
TextNode* lt_matcher = zone->
New<TextNode>(lt_atom,
false, lt_at_end);
REGISTER_NODE(lt_matcher);
// Inner choice: CRLF first, then single LT.
ChoiceNode* inner_choice = zone->
New<ChoiceNode>(
2, zone);
inner_choice->AddAlternative(GuardedAlternative(crlf_matcher));
inner_choice->AddAlternative(GuardedAlternative(lt_matcher));
REGISTER_NODE(inner_choice);
// Wrap inner choice in a positive lookahead.
Node* lookahead_node = lookahead.ForMatch(compiler, inner_choice);
// Outer choice: either the trailing-terminator lookahead matches, or
// we're already at end-of-input.
ChoiceNode* result = zone->
New<ChoiceNode>(
2, zone);
result->AddAlternative(GuardedAlternative(lookahead_node));
result->AddAlternative(
GuardedAlternative(AssertionNode::AtEnd(on_success)));
REGISTER_NODE(result);
return result;
}
case Type::END_OF_LINE: {
// Compile $ in multiline regexps as an alternation with a positive
// lookahead in one side and an end-of-input on the other side.
// We need two registers for the lookahead.
int stack_pointer_register = compiler->AllocateRegister();
int position_register = compiler->AllocateRegister();
// The ChoiceNode to distinguish between a newline and end-of-input.
ChoiceNode* result = zone->
New<ChoiceNode>(
2, zone);
// Create a newline atom.
ZoneList<CharacterRange>* newline_ranges =
zone->
New<ZoneList<CharacterRange>>(
3, zone);
CharacterRange::AddClassEscape(StandardCharacterSet::kLineTerminator,
newline_ranges,
false, zone);
ActionNode* submatch_success = ActionNode::PositiveSubmatchSuccess(
stack_pointer_register, position_register,
0,
// No captures inside.
-
1,
// Ignored if no captures.
on_success);
REGISTER_NODE(submatch_success);
ClassRanges* newline_atom =
zone->
New<ClassRanges>(StandardCharacterSet::kLineTerminator);
TextNode* newline_matcher =
zone->
New<TextNode>(newline_atom,
false, submatch_success);
REGISTER_NODE(newline_matcher);
// Create an end-of-input matcher.
Node* end_of_line = ActionNode::BeginPositiveSubmatch(
stack_pointer_register, position_register, newline_matcher,
submatch_success);
REGISTER_NODE(end_of_line);
// Add the two alternatives to the ChoiceNode.
GuardedAlternative eol_alternative(end_of_line);
result->AddAlternative(eol_alternative);
GuardedAlternative end_alternative(AssertionNode::AtEnd(on_success));
result->AddAlternative(end_alternative);
REGISTER_NODE(result);
return result;
}
default:
UNREACHABLE();
}
}
Node* BackReference::ToNodeImpl(Compiler* compiler, Node* on_success) {
Node* backref_node = on_success;
// Only one of the captures in the list can actually match. Since
// back-references to unmatched captures are treated as empty, we can simply
// create back-references to all possible captures.
for (
auto capture : *captures()) {
backref_node = compiler->zone()->
New<BackReferenceNode>(
Capture::StartRegister(capture->index()),
Capture::EndRegister(capture->index()), compiler->read_backward(),
backref_node);
REGISTER_NODE(backref_node);
}
return backref_node;
}
Node* Empty::ToNodeImpl(Compiler* compiler, Node* on_success) {
return on_success;
}
namespace {
class V8_NODISCARD ModifiersScope {
public:
ModifiersScope(Compiler* compiler, Flags flags)
: compiler_(compiler), previous_flags_(compiler->flags()) {
compiler->set_flags(flags);
}
~ModifiersScope() { compiler_->set_flags(previous_flags_); }
private:
Compiler* compiler_;
const Flags previous_flags_;
};
}
// namespace
Node* Group::ToNodeImpl(Compiler* compiler, Node* on_success) {
// If no flags are modified, simply convert and return the body.
if (flags() == compiler->flags()) {
return body_->ToNode(compiler, on_success);
}
// Reset flags for successor node.
const Flags old_flags = compiler->flags();
on_success = ActionNode::ModifyFlags(old_flags, on_success);
// Convert body using modifier.
ModifiersScope modifiers_scope(compiler, flags());
Node* body = body_->ToNode(compiler, on_success);
if (body->IsBacktrack())
return body;
// Wrap body into modifier node.
Node* modified_body = ActionNode::ModifyFlags(flags(), body);
return modified_body;
}
Lookaround::Builder::Builder(
bool is_positive, Node* on_success,
Compiler* compiler,
int stack_pointer_register,
int position_register,
int capture_register_count,
int capture_register_start)
: is_positive_(is_positive),
on_success_(on_success),
stack_pointer_register_(stack_pointer_register),
position_register_(position_register) {
if (is_positive_) {
on_match_success_ = ActionNode::PositiveSubmatchSuccess(
stack_pointer_register, position_register, capture_register_count,
capture_register_start, on_success_);
}
else {
Zone* zone = on_success_->zone();
on_match_success_ = zone->
New<NegativeSubmatchSuccess>(
stack_pointer_register, position_register, capture_register_count,
capture_register_start, zone);
}
REGISTER_NODE(on_match_success_);
}
Node* Lookaround::Builder::ForMatch(Compiler* compiler, Node* match) {
if (is_positive_) {
ActionNode* on_match_success = on_match_success_->AsActionNode();
Node* node = ActionNode::BeginPositiveSubmatch(
stack_pointer_register_, position_register_, match, on_match_success);
REGISTER_NODE(node);
return node;
}
else {
Zone* zone = on_success_->zone();
// We use a ChoiceNode to represent the negative lookaround. The first
// alternative is the negative match. On success, the end node backtracks.
// On failure, the second alternative is tried and leads to success.
// NegativeLookaroundChoiceNode is a special ChoiceNode that ignores the
// first exit when calculating quick checks.
ChoiceNode* choice_node = zone->
New<NegativeLookaroundChoiceNode>(
GuardedAlternative(match), GuardedAlternative(on_success_), zone);
REGISTER_NODE(choice_node);
Node* node = ActionNode::BeginNegativeSubmatch(
stack_pointer_register_, position_register_, choice_node);
REGISTER_NODE(node);
return node;
}
}
Node* Lookaround::ToNodeImpl(Compiler* compiler, Node* on_success) {
int stack_pointer_register = compiler->AllocateRegister();
int position_register = compiler->AllocateRegister();
const int registers_per_capture =
2;
const int register_of_first_capture =
2;
int register_count = capture_count_ * registers_per_capture;
int register_start =
register_of_first_capture + capture_from_ * registers_per_capture;
Node* result;
bool was_reading_backward = compiler->read_backward();
compiler->set_read_backward(type() == LOOKBEHIND);
Builder builder(is_positive(), on_success, compiler, stack_pointer_register,
position_register, register_count, register_start);
Node* match = body_->ToNode(compiler, builder.on_match_success());
if (match->IsBacktrack() && (is_positive() || compiler->IsRegExpTooBig())) {
compiler->set_read_backward(was_reading_backward);
return match;
}
result = builder.ForMatch(compiler, match);
compiler->set_read_backward(was_reading_backward);
return result;
}
Node* Capture::ToNodeImpl(Compiler* compiler, Node* on_success) {
return ToNode(body(), index(), compiler, on_success);
}
// static
Node* Capture::ToNode(Tree* body,
int index, Compiler* compiler,
Node* on_success) {
DCHECK_NOT_NULL(body);
int start_reg = Capture::StartRegister(index);
int end_reg = Capture::EndRegister(index);
if (compiler->read_backward()) std::swap(start_reg, end_reg);
Node* store_end = ActionNode::StorePosition(end_reg, on_success);
REGISTER_NODE(store_end);
Node* body_node = body->ToNode(compiler, store_end);
if (body_node->IsBacktrack())
return body_node;
Node* node = ActionNode::StorePosition(start_reg, body_node);
REGISTER_NODE(node);
return node;
}
namespace {
class AssertionSequenceRewriter final {
public:
// TODO(jgruber): Consider moving this to a separate AST tree rewriter pass
// instead of sprinkling rewrites into the AST->Node conversion process.
static void MaybeRewrite(ZoneList<Tree*>* terms, Zone* zone) {
AssertionSequenceRewriter rewriter(terms, zone);
static constexpr
int kNoIndex = -
1;
int from = kNoIndex;
for (
int i =
0; i < terms->length(); i++) {
Tree* t = terms->at(i);
if (from == kNoIndex && t->IsAssertion()) {
from = i;
// Start a sequence.
}
else if (from != kNoIndex && !t->IsAssertion()) {
// Terminate and process the sequence.
if (i - from >
1) rewriter.Rewrite(from, i);
from = kNoIndex;
}
}
if (from != kNoIndex && terms->length() - from >
1) {
rewriter.Rewrite(from, terms->length());
}
}
// All assertions are zero width. A consecutive sequence of assertions is
// order-independent. There's two ways we can optimize here:
// 1. fold all identical assertions.
// 2. if any assertion combinations are known to fail (e.g. \b\B), the entire
// sequence fails.
void Rewrite(
int from,
int to) {
DCHECK_GT(to, from +
1);
// Bitfield of all seen assertions.
uint32_t seen_assertions =
0;
static_assert(
static_cast<
int>(Assertion::Type::LAST_ASSERTION_TYPE) <
kUInt32Size * kBitsPerByte);
for (
int i = from; i < to; i++) {
Assertion* t = terms_->at(i)->AsAssertion();
const uint32_t bit =
1 <<
static_cast<
int>(t->assertion_type());
if (seen_assertions & bit) {
// Fold duplicates.
terms_->Set(i, zone_->
New<Empty>());
}
seen_assertions |= bit;
}
// Collapse failures.
const uint32_t always_fails_mask =
1 <<
static_cast<
int>(Assertion::Type::BOUNDARY) |
1 <<
static_cast<
int>(Assertion::Type::NON_BOUNDARY);
if ((seen_assertions & always_fails_mask) == always_fails_mask) {
ReplaceSequenceWithFailure(from, to);
}
}
void ReplaceSequenceWithFailure(
int from,
int to) {
// Replace the entire sequence with a single node that always fails.
// TODO(jgruber): Consider adding an explicit Fail kind. Until then, the
// negated '*' (everything) range serves the purpose.
ZoneList<CharacterRange>* ranges =
zone_->
New<ZoneList<CharacterRange>>(
0, zone_);
ClassRanges* cc = zone_->
New<ClassRanges>(zone_, ranges);
terms_->Set(from, cc);
// Zero out the rest.
Empty* empty = zone_->
New<Empty>();
for (
int i = from +
1; i < to; i++) terms_->Set(i, empty);
}
private:
AssertionSequenceRewriter(ZoneList<Tree*>* terms, Zone* zone)
: zone_(zone), terms_(terms) {}
Zone* zone_;
ZoneList<Tree*>* terms_;
};
}
// namespace
Node* Alternative::ToNodeImpl(Compiler* compiler, Node* on_success) {
ZoneList<Tree*>* children = nodes();
AssertionSequenceRewriter::MaybeRewrite(children, compiler->zone());
TRACE_WITH_NODE(
"* After assertion sequence rewrite: ",
this);
Node* current = on_success;
if (compiler->read_backward()) {
for (
int i =
0; i < children->length(); i++) {
current = children->at(i)->ToNode(compiler, current);
}
}
else {
for (
int i = children->length() -
1; i >=
0; i--) {
current = children->at(i)->ToNode(compiler, current);
}
}
return current;
}
namespace {
void AddClass(
const int* elmv,
int elmc, ZoneList<CharacterRange>* ranges,
Zone* zone) {
elmc--;
DCHECK_EQ(kRangeEndMarker, elmv[elmc]);
for (
int i =
0; i < elmc; i +=
2) {
DCHECK(elmv[i] < elmv[i +
1]);
ranges->Add(CharacterRange::Range(elmv[i], elmv[i +
1] -
1), zone);
}
}
void AddClassNegated(
const int* elmv,
int elmc,
ZoneList<CharacterRange>* ranges, Zone* zone) {
elmc--;
DCHECK_EQ(kRangeEndMarker, elmv[elmc]);
DCHECK_NE(
0x0000, elmv[
0]);
DCHECK_NE(kMaxCodePoint, elmv[elmc -
1]);
base::uc16 last =
0x0000;
for (
int i =
0; i < elmc; i +=
2) {
DCHECK(last <= elmv[i] -
1);
DCHECK(elmv[i] < elmv[i +
1]);
ranges->Add(CharacterRange::Range(last, elmv[i] -
1), zone);
last = elmv[i +
1];
}
ranges->Add(CharacterRange::Range(last, kMaxCodePoint), zone);
}
}
// namespace
void CharacterRange::AddClassEscape(StandardCharacterSet standard_character_set,
ZoneList<CharacterRange>* ranges,
bool add_unicode_case_equivalents,
Zone* zone) {
if (add_unicode_case_equivalents &&
(standard_character_set == StandardCharacterSet::kWord ||
standard_character_set == StandardCharacterSet::kNotWord)) {
// See
// https://tc39.es/ecma262/#sec-runtime-semantics-wordcharacters-abstract-operation
// In case of unicode and ignore_case, we need to create the closure over
// case equivalent characters before negating.
ZoneList<CharacterRange>* new_ranges =
zone->
New<ZoneList<CharacterRange>>(
2, zone);
AddClass(kWordRanges, kWordRangeCount, new_ranges, zone);
AddUnicodeCaseEquivalents(new_ranges, zone);
if (standard_character_set == StandardCharacterSet::kNotWord) {
ZoneList<CharacterRange>* negated =
zone->
New<ZoneList<CharacterRange>>(
2, zone);
CharacterRange::Negate(new_ranges, negated, zone);
new_ranges = negated;
}
ranges->AddAll(*new_ranges, zone);
return;
}
switch (standard_character_set) {
case StandardCharacterSet::kWhitespace:
AddClass(kSpaceRanges, kSpaceRangeCount, ranges, zone);
break;
case StandardCharacterSet::kNotWhitespace:
AddClassNegated(kSpaceRanges, kSpaceRangeCount, ranges, zone);
break;
case StandardCharacterSet::kWord:
AddClass(kWordRanges, kWordRangeCount, ranges, zone);
break;
case StandardCharacterSet::kNotWord:
AddClassNegated(kWordRanges, kWordRangeCount, ranges, zone);
break;
case StandardCharacterSet::kDigit:
AddClass(kDigitRanges, kDigitRangeCount, ranges, zone);
break;
case StandardCharacterSet::kNotDigit:
AddClassNegated(kDigitRanges, kDigitRangeCount, ranges, zone);
break;
// This is the set of characters matched by the $ and ^ symbols
// in multiline mode.
case StandardCharacterSet::kLineTerminator:
AddClass(kLineTerminatorRanges, kLineTerminatorRangeCount, ranges, zone);
break;
case StandardCharacterSet::kNotLineTerminator:
AddClassNegated(kLineTerminatorRanges, kLineTerminatorRangeCount, ranges,
zone);
break;
// This is not a character range as defined by the spec but a
// convenient shorthand for a character class that matches any
// character.
case StandardCharacterSet::kEverything:
ranges->Add(CharacterRange::Everything(), zone);
break;
}
}
// static
// Only for /i, not for /ui or /vi.
void CharacterRange::AddCaseEquivalents(Isolate* isolate, Zone* zone,
ZoneList<CharacterRange>* ranges,
bool is_one_byte) {
CharacterRange::Canonicalize(ranges);
int range_count = ranges->length();
#ifdef V8_INTL_SUPPORT
icu::UnicodeSet others;
for (
int i =
0; i < range_count; i++) {
CharacterRange range = ranges->at(i);
base::uc32 from = range.from();
if (from > kMaxUtf16CodeUnit)
continue;
base::uc32 to = std::min({range.to(), kMaxUtf16CodeUnitU});
// Nothing to be done for surrogates.
if (from >= kLeadSurrogateStart && to <= kTrailSurrogateEnd)
continue;
if (is_one_byte && !RangeContainsLatin1Equivalents(range)) {
if (from > String::kMaxOneByteCharCode)
continue;
if (to > String::kMaxOneByteCharCode) to = String::kMaxOneByteCharCode;
}
others.add(from, to);
}
// Compute the set of additional characters that should be added,
// using UnicodeSet::closeOver. ECMA 262 defines slightly different
// case-folding rules than Unicode, so some characters that are
// added by closeOver do not match anything other than themselves in
// JS. For example, 'ſ' (U+017F LATIN SMALL LETTER LONG S) is the
// same case-insensitive character as 's' or 'S' according to
// Unicode, but does not match any other character in JS. To handle
// this case, we add such characters to the IgnoreSet and filter
// them out. We filter twice: once before calling closeOver (to
// prevent 'ſ' from adding 's'), and once after calling closeOver
// (to prevent 's' from adding 'ſ'). See regexp/special-case.h for
// more information.
icu::UnicodeSet already_added(others);
others.removeAll(CaseFolding::IgnoreSet());
others.closeOver(USET_CASE_INSENSITIVE);
others.removeAll(CaseFolding::IgnoreSet());
others.removeAll(already_added);
// Add others to the ranges
for (int32_t i =
0; i < others.getRangeCount(); i++) {
UChar32 from = others.getRangeStart(i);
UChar32 to = others.getRangeEnd(i);
if (from == to) {
ranges->Add(CharacterRange::Singleton(from), zone);
}
else {
ranges->Add(CharacterRange::Range(from, to), zone);
}
}
#else
for (
int i =
0; i < range_count; i++) {
CharacterRange range = ranges->at(i);
base::uc32 bottom = range.from();
if (bottom > kMaxUtf16CodeUnit)
continue;
base::uc32 top = std::min({range.to(), kMaxUtf16CodeUnitU});
// Nothing to be done for surrogates.
if (bottom >= kLeadSurrogateStart && top <= kTrailSurrogateEnd)
continue;
if (is_one_byte && !RangeContainsLatin1Equivalents(range)) {
if (bottom > String::kMaxOneByteCharCode)
continue;
if (top > String::kMaxOneByteCharCode) top = String::kMaxOneByteCharCode;
}
unibrow::uchar chars[unibrow::Ecma262UnCanonicalize::kMaxWidth];
if (top == bottom) {
// If this is a singleton we just expand the one character.
int length = isolate->jsregexp_uncanonicalize()->get(bottom,
'\0', chars);
for (
int j =
0; j < length; j++) {
base::uc32 chr = chars[j];
if (chr != bottom) {
ranges->Add(CharacterRange::Singleton(chars[j]), zone);
}
}
}
else {
// If this is a range we expand the characters block by block, expanding
// contiguous subranges (blocks) one at a time. The approach is as
// follows. For a given start character we look up the remainder of the
// block that contains it (represented by the end point), for instance we
// find 'z' if the character is 'c'. A block is characterized by the
// property that all characters uncanonicalize in the same way, except
// that each entry in the result is incremented by the distance from the
// first element. So a-z is a block because 'a' uncanonicalizes to ['a',
// 'A'] and the k'th letter uncanonicalizes to ['a' + k, 'A' + k]. Once
// we've found the end point we look up its uncanonicalization and
// produce a range for each element. For instance for [c-f] we look up
// ['z', 'Z'] and produce [c-f] and [C-F]. We then only add a range if
// it is not already contained in the input, so [c-f] will be skipped but
// [C-F] will be added. If this range is not completely contained in a
// block we do this for all the blocks covered by the range (handling
// characters that is not in a block as a "singleton block").
unibrow::uchar equivalents[unibrow::Ecma262UnCanonicalize::kMaxWidth];
base::uc32 pos = bottom;
while (pos <= top) {
int length =
isolate->jsregexp_canonrange()->get(pos,
'\0', equivalents);
base::uc32 block_end;
if (length ==
0) {
block_end = pos;
}
else {
DCHECK_EQ(
1, length);
block_end = equivalents[
0];
}
int end = (block_end > top) ? top : block_end;
length = isolate->jsregexp_uncanonicalize()->get(block_end,
'\0',
equivalents);
for (
int j =
0; j < length; j++) {
base::uc32 c = equivalents[j];
base::uc32 range_from = c - (block_end - pos);
base::uc32 range_to = c - (block_end - end);
if (!(bottom <= range_from && range_to <= top)) {
ranges->Add(CharacterRange::Range(range_from, range_to), zone);
}
}
pos = end +
1;
}
}
}
#endif // V8_INTL_SUPPORT
}
bool CharacterRange::IsCanonical(
const ZoneList<CharacterRange>* ranges) {
DCHECK_NOT_NULL(ranges);
int n = ranges->length();
if (n <=
1)
return true;
base::uc32 max = ranges->at(
0).to();
for (
int i =
1; i < n; i++) {
CharacterRange next_range = ranges->at(i);
if (next_range.from() <= max +
1)
return false;
max = next_range.to();
}
return true;
}
ZoneList<CharacterRange>* CharacterSet::ranges(Zone* zone) {
if (ranges_ == nullptr) {
ranges_ = zone->
New<ZoneList<CharacterRange>>(
2, zone);
CharacterRange::AddClassEscape(standard_set_type_.value(), ranges_,
false,
zone);
}
return ranges_;
}
namespace {
// Move a number of elements in a zonelist to another position
// in the same list. Handles overlapping source and target areas.
void MoveRanges(ZoneList<CharacterRange>* list,
int from,
int to,
int count) {
// Ranges are potentially overlapping.
if (from < to) {
for (
int i = count -
1; i >=
0; i--) {
list->at(to + i) = list->at(from + i);
}
}
else {
for (
int i =
0; i < count; i++) {
list->at(to + i) = list->at(from + i);
}
}
}
int InsertRangeInCanonicalList(ZoneList<CharacterRange>* list,
int count,
CharacterRange insert) {
// Inserts a range into list[0..count[, which must be sorted
// by from value and non-overlapping and non-adjacent, using at most
// list[0..count] for the result. Returns the number of resulting
// canonicalized ranges. Inserting a range may collapse existing ranges into
// fewer ranges, so the return value can be anything in the range 1..count+1.
base::uc32 from = insert.from();
base::uc32 to = insert.to();
int start_pos =
0;
int end_pos = count;
for (
int i = count -
1; i >=
0; i--) {
CharacterRange current = list->at(i);
if (current.from() > to +
1) {
end_pos = i;
}
else if (current.to() +
1 < from) {
start_pos = i +
1;
break;
}
}
// Inserted range overlaps, or is adjacent to, ranges at positions
// [start_pos..end_pos[. Ranges before start_pos or at or after end_pos are
// not affected by the insertion.
// If start_pos == end_pos, the range must be inserted before start_pos.
// if start_pos < end_pos, the entire range from start_pos to end_pos
// must be merged with the insert range.
if (start_pos == end_pos) {
// Insert between existing ranges at position start_pos.
if (start_pos < count) {
MoveRanges(list, start_pos, start_pos +
1, count - start_pos);
}
list->at(start_pos) = insert;
return count +
1;
}
if (start_pos +
1 == end_pos) {
// Replace single existing range at position start_pos.
CharacterRange to_replace = list->at(start_pos);
int new_from = std::min(to_replace.from(), from);
int new_to = std::max(to_replace.to(), to);
list->at(start_pos) = CharacterRange::Range(new_from, new_to);
return count;
}
// Replace a number of existing ranges from start_pos to end_pos - 1.
// Move the remaining ranges down.
int new_from = std::min(list->at(start_pos).from(), from);
int new_to = std::max(list->at(end_pos -
1).to(), to);
if (end_pos < count) {
MoveRanges(list, end_pos, start_pos +
1, count - end_pos);
}
list->at(start_pos) = CharacterRange::Range(new_from, new_to);
return count - (end_pos - start_pos) +
1;
}
}
// namespace
void CharacterSet::Canonicalize() {
// Special/default classes are always considered canonical. The result
// of calling ranges() will be sorted.
if (ranges_ == nullptr)
return;
CharacterRange::Canonicalize(ranges_);
}
// static
void CharacterRange::Canonicalize(ZoneList<CharacterRange>* character_ranges) {
if (character_ranges->length() <=
1)
return;
// Check whether ranges are already canonical (increasing, non-overlapping,
// non-adjacent).
int n = character_ranges->length();
base::uc32 max = character_ranges->at(
0).to();
int i =
1;
while (i < n) {
CharacterRange current = character_ranges->at(i);
if (current.from() <= max +
1) {
break;
}
max = current.to();
i++;
}
// Canonical until the i'th range. If that's all of them, we are done.
if (i == n)
return;
// The ranges at index i and forward are not canonicalized. Make them so by
// doing the equivalent of insertion sort (inserting each into the previous
// list, in order).
// Notice that inserting a range can reduce the number of ranges in the
// result due to combining of adjacent and overlapping ranges.
int read = i;
// Range to insert.
int num_canonical = i;
// Length of canonicalized part of list.
do {
num_canonical = InsertRangeInCanonicalList(character_ranges, num_canonical,
character_ranges->at(read));
read++;
}
while (read < n);
character_ranges->Rewind(num_canonical);
DCHECK(CharacterRange::IsCanonical(character_ranges));
}
// static
void CharacterRange::Negate(
const ZoneList<CharacterRange>* ranges,
ZoneList<CharacterRange>* negated_ranges,
Zone* zone) {
DCHECK(CharacterRange::IsCanonical(ranges));
DCHECK_EQ(
0, negated_ranges->length());
int range_count = ranges->length();
base::uc32 from =
0;
int i =
0;
if (range_count >
0 && ranges->at(
0).from() ==
0) {
from = ranges->at(
0).to() +
1;
i =
1;
}
while (i < range_count) {
CharacterRange range = ranges->at(i);
negated_ranges->Add(CharacterRange::Range(from, range.from() -
1), zone);
from = range.to() +
1;
i++;
}
if (from < kMaxCodePoint) {
negated_ranges->Add(CharacterRange::Range(from, kMaxCodePoint), zone);
}
}
// static
void CharacterRange::Intersect(
const ZoneList<CharacterRange>* lhs,
const ZoneList<CharacterRange>* rhs,
ZoneList<CharacterRange>* intersection,
Zone* zone) {
DCHECK(CharacterRange::IsCanonical(lhs));
DCHECK(CharacterRange::IsCanonical(rhs));
DCHECK_EQ(
0, intersection->length());
int lhs_index =
0;
int rhs_index =
0;
while (lhs_index < lhs->length() && rhs_index < rhs->length()) {
// Skip non-overlapping ranges.
if (lhs->at(lhs_index).to() < rhs->at(rhs_index).from()) {
lhs_index++;
continue;
}
if (rhs->at(rhs_index).to() < lhs->at(lhs_index).from()) {
rhs_index++;
continue;
}
base::uc32 from =
std::max(lhs->at(lhs_index).from(), rhs->at(rhs_index).from());
base::uc32 to = std::min(lhs->at(lhs_index).to(), rhs->at(rhs_index).to());
intersection->Add(CharacterRange::Range(from, to), zone);
if (to == lhs->at(lhs_index).to()) {
lhs_index++;
}
else {
rhs_index++;
}
}
DCHECK(IsCanonical(intersection));
}
namespace {
// Advance |index| and set |from| and |to| to the new range, if not out of
// bounds of |range|, otherwise |from| is set to a code point beyond the legal
// unicode character range.
void SafeAdvanceRange(
const ZoneList<CharacterRange>* range,
int* index,
base::uc32* from, base::uc32* to) {
++(*index);
if (*index < range->length()) {
*from = range->at(*index).from();
*to = range->at(*index).to();
}
else {
*from = kMaxCodePoint +
1;
}
}
}
// namespace
// static
void CharacterRange::Subtract(
const ZoneList<CharacterRange>* src,
const ZoneList<CharacterRange>* to_remove,
ZoneList<CharacterRange>* result, Zone* zone) {
DCHECK(CharacterRange::IsCanonical(src));
DCHECK(CharacterRange::IsCanonical(to_remove));
DCHECK_EQ(
0, result->length());
if (src->is_empty())
return;
int src_index =
0;
int to_remove_index =
0;
base::uc32 from = src->at(src_index).from();
base::uc32 to = src->at(src_index).to();
while (src_index < src->length() && to_remove_index < to_remove->length()) {
CharacterRange remove_range = to_remove->at(to_remove_index);
if (remove_range.to() < from) {
// (a) Non-overlapping case, ignore current to_remove range.
// |-------|
// |-------|
to_remove_index++;
}
else if (to < remove_range.from()) {
// (b) Non-overlapping case, add full current range to result.
// |-------|
// |-------|
result->Add(CharacterRange::Range(from, to), zone);
SafeAdvanceRange(src, &src_index, &from, &to);
}
else if (from >= remove_range.from() && to <= remove_range.to()) {
// (c) Current to_remove range fully covers current range.
// |---|
// |-------|
SafeAdvanceRange(src, &src_index, &from, &to);
}
else if (from < remove_range.from() && to > remove_range.to()) {
// (d) Split current range.
// |-------|
// |---|
result->Add(CharacterRange::Range(from, remove_range.from() -
1), zone);
from = remove_range.to() +
1;
to_remove_index++;
}
else if (from < remove_range.from()) {
// (e) End current range.
// |-------|
// |-------|
to = remove_range.from() -
1;
result->Add(CharacterRange::Range(from, to), zone);
SafeAdvanceRange(src, &src_index, &from, &to);
}
else if (to > remove_range.to()) {
// (f) Modify start of current range.
// |-------|
// |-------|
from = remove_range.to() +
1;
to_remove_index++;
}
else {
UNREACHABLE();
}
}
// The last range needs special treatment after |to_remove| is exhausted, as
// |from| might have been modified by the last |to_remove| range and |to| was
// not yet known (i.e. cases d and f).
if (from <= to) {
result->Add(CharacterRange::Range(from, to), zone);
}
src_index++;
// Add remaining ranges after |to_remove| is exhausted.
for (; src_index < src->length(); src_index++) {
result->Add(src->at(src_index), zone);
}
DCHECK(IsCanonical(result));
}
// static
void CharacterRange::ClampToOneByte(ZoneList<CharacterRange>* ranges) {
DCHECK(IsCanonical(ranges));
// Drop all ranges that don't contain one-byte code units, and clamp the last
// range s.t. it likewise only contains one-byte code units. Note this relies
// on `ranges` being canonicalized, i.e. sorted and non-overlapping.
static constexpr base::uc32 max_char = String::kMaxOneByteCharCodeU;
int n = ranges->length();
for (; n >
0; n--) {
CharacterRange& r = ranges->at(n -
1);
if (r.from() <= max_char) {
r.to_ = std::min(r.to_, max_char);
break;
}
}
ranges->Rewind(n);
}
// static
bool CharacterRange::Equals(
const ZoneList<CharacterRange>* lhs,
const ZoneList<CharacterRange>* rhs) {
DCHECK(IsCanonical(lhs));
DCHECK(IsCanonical(rhs));
if (lhs->length() != rhs->length())
return false;
for (
int i =
0; i < lhs->length(); i++) {
if (lhs->at(i) != rhs->at(i))
return false;
}
return true;
}
namespace {
// Scoped object to keep track of how much we unroll quantifier loops in the
// regexp graph generator.
class ExpansionLimiter {
public:
static const int kMaxExpansionFactor =
6;
ExpansionLimiter(Compiler* compiler,
int factor)
: compiler_(compiler),
saved_expansion_factor_(compiler->current_expansion_factor()),
ok_to_expand_(saved_expansion_factor_ <= kMaxExpansionFactor) {
DCHECK_LT(
0, factor);
if (ok_to_expand_) {
if (factor > kMaxExpansionFactor) {
// Avoid integer overflow of the current expansion factor.
ok_to_expand_ =
false;
compiler->set_current_expansion_factor(kMaxExpansionFactor +
1);
}
else {
int new_factor = saved_expansion_factor_ * factor;
ok_to_expand_ = (new_factor <= kMaxExpansionFactor);
compiler->set_current_expansion_factor(new_factor);
}
}
}
~ExpansionLimiter() {
compiler_->set_current_expansion_factor(saved_expansion_factor_);
}
bool ok_to_expand() {
return ok_to_expand_; }
private:
Compiler* compiler_;
int saved_expansion_factor_;
bool ok_to_expand_;
DISALLOW_IMPLICIT_CONSTRUCTORS(ExpansionLimiter);
};
}
// namespace
// static
Node* Quantifier::ToNode(
int min,
int max,
bool is_greedy, Tree* body,
Compiler* compiler, Node* on_success,
bool not_at_start) {
#ifdef V8_ENABLE_REGEXP_DIAGNOSTICS
TraceTreeScope trace_tree_scope(compiler->diagnostics());
#endif
TRACE(
"* Handling quantifier {"
<< min <<
"," << (max == kInfinity ?
"∞" : std::to_string(max)) <<
"}");
// x{f, t} becomes this:
//
// (r++)<-.
// | `
// | (x)
// v ^
// (r=0)-->(?)---/ [if r < t]
// |
// [if r >= f] \----> ...
//
// 15.10.2.5 RepeatMatcher algorithm.
// The parser has already eliminated the case where max is 0. In the case
// where max_match is zero the parser has removed the quantifier if min was
// > 0 and removed the atom if min was 0. See AddQuantifierToAtom.
// If we know that we cannot match zero length then things are a little
// simpler since we don't need to make the special zero length match check
// from step 2.1. If the min and max are small we can unroll a little in
// this case.
static const int kMaxUnrolledMinMatches =
3;
// Unroll (foo)+ and (foo){3,}
static const int kMaxUnrolledMaxMatches =
3;
// Unroll (foo)? and (foo){x,3}
if (max ==
0)
return on_success;
// This can happen due to recursion.
bool body_can_be_empty = (body->min_match() ==
0);
int body_start_reg = Compiler::kNoRegister;
Zone* zone = compiler->zone();
Interval capture_registers =
body->CaptureRegisters(StackLimiter(Node::kRecursionBudget));
if (!capture_registers.is_valid()) {
compiler->SetRegExpTooBig();
return zone->
New<EndNode>(EndNode::BACKTRACK, zone);
}
// At the start of the next iteration of a quantifier the captures must be
// cleared, so that /(?:x(.)?z){2}/ when applied to "xyzxz" captures ""
// (rather than "y" from the first repeat). However, if the max number of
// iterations is 1 then there is no 'next repeat' so we don't need to do this.
bool needs_capture_clearing = !capture_registers.is_empty() && max !=
1;
bool want_unroll = compiler->optimize() && v8_flags.regexp_unroll;
if (body_can_be_empty) {
body_start_reg = compiler->AllocateRegister();
}
else if (want_unroll && !needs_capture_clearing) {
// Only unroll if there are no captures and the body can't be
// empty.
{
ExpansionLimiter limiter(compiler, min + ((max != min) ?
1 :
0));
if (min >
0 && min <= kMaxUnrolledMinMatches && limiter.ok_to_expand()) {
TRACE(
"* Recurse for remainder after unrolling (unrolling "
<< min <<
" times)");
int new_max = (max == kInfinity) ? max : max - min;
// Recurse once to get the loop or optional matches after the fixed
// ones.
Node* answer =
ToNode(
0, new_max, is_greedy, body, compiler, on_success,
true);
// Unroll the forced matches from 0 to min. This can cause chains of
// TextNodes (which the parser does not generate). These should be
// combined if it turns out they hinder good code generation.
TRACE(
"* Unrolling loop " << min <<
" time(s) for min matches");
for (
int i =
0; i < min; i++) {
TRACE(
"* Iteration " << i +
1 <<
" / " << min);
answer = body->ToNode(compiler, answer);
}
return answer;
}
}
if (max <= kMaxUnrolledMaxMatches && min ==
0) {
DCHECK_LT(
0, max);
// Due to the 'if' above.
ExpansionLimiter limiter(compiler, max);
if (limiter.ok_to_expand()) {
TRACE(
"* Unrolling loop " << max <<
" times for max matches");
// Unroll the optional matches up to max.
Node* answer = on_success;
for (
int i =
0; i < max; i++) {
TRACE(
"* Iteration " << i +
1 <<
" / " << max);
ChoiceNode* alternation = zone->
New<ChoiceNode>(
2, zone);
if (is_greedy) {
alternation->AddAlternative(
GuardedAlternative(body->ToNode(compiler, answer)));
alternation->AddAlternative(GuardedAlternative(on_success));
}
else {
alternation->AddAlternative(GuardedAlternative(on_success));
alternation->AddAlternative(
GuardedAlternative(body->ToNode(compiler, answer)));
}
answer = alternation;
if (not_at_start && !compiler->read_backward()) {
alternation->set_not_at_start();
}
REGISTER_NODE(alternation);
}
return answer;
}
}
}
bool has_min = min >
0;
bool has_max = max < Tree::kInfinity;
bool needs_counter = has_min || has_max;
int reg_ctr =
needs_counter ? compiler->AllocateRegister() : Compiler::kNoRegister;
LoopChoiceNode* center = zone->
New<LoopChoiceNode>(
body->min_match() ==
0, compiler->read_backward(), zone);
if (not_at_start && !compiler->read_backward()) center->set_not_at_start();
Node* loop_return = center;
if (needs_counter) {
loop_return = ActionNode::IncrementRegister(reg_ctr, loop_return);
REGISTER_NODE(loop_return);
}
if (body_can_be_empty) {
// If the body can be empty we need to check if it was and then
// backtrack.
loop_return =
ActionNode::EmptyMatchCheck(body_start_reg, reg_ctr, min, loop_return);
REGISTER_NODE(loop_return);
}
Node* body_node = body->ToNode(compiler, loop_return);
if (body_node->IsBacktrack()) {
// Body can never match. If there is a minimum number of iterations that
// means this whole part of the regexp can't match, so we just return the
// never-match (backtrack) node.
if (has_min)
return body_node;
// Since there is no minimum number of iterations and the body can't match
// we can go straight to whatever comes after the quantifier.
return on_success;
}
if (body_can_be_empty) {
// If the body can be empty we need to store the start position
// so we can bail out if it was empty.
body_node = ActionNode::RestorePosition(body_start_reg, body_node);
REGISTER_NODE(body_node);
}
if (needs_capture_clearing) {
// Before entering the body of this loop we need to clear captures.
body_node = ActionNode::ClearCaptures(capture_registers, body_node);
REGISTER_NODE(body_node);
}
GuardedAlternative body_alt(body_node);
if (has_max) {
Guard* body_guard = zone->
New<Guard>(reg_ctr, Guard::LT, max);
body_alt.AddGuard(body_guard, zone);
}
GuardedAlternative rest_alt(on_success);
if (has_min) {
Guard* rest_guard = compiler->zone()->
New<Guard>(reg_ctr, Guard::GEQ, min);
rest_alt.AddGuard(rest_guard, zone);
}
if (is_greedy) {
center->AddLoopAlternative(body_alt);
center->AddContinueAlternative(rest_alt);
}
else {
center->AddContinueAlternative(rest_alt);
center->AddLoopAlternative(body_alt);
}
REGISTER_NODE(center);
Node* result = center;
if (min >
0 && body->min_match() >
0 && !compiler->read_backward()) {
uint8_t eats = base::saturated_cast<uint8_t>(
std::min(
256, min) * std::min(
256, body->min_match()));
result = ActionNode::EatsAtLeast(eats, result);
REGISTER_NODE(result);
}
if (needs_counter) {
result = ActionNode::SetRegisterForLoop(reg_ctr,
0, result);
REGISTER_NODE(result);
}
return result;
}
#undef TRACE
#undef TRACE_WITH_NODE
#undef REGISTER_NODE
}
// namespace regexp
}
// namespace internal
}
// namespace v8
