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authorMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
committerMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
commit5f8de423f190bbb79a62f804151bc24824fa32d8 (patch)
tree10027f336435511475e392454359edea8e25895d /js/src/irregexp/RegExpEngine.cpp
parent49ee0794b5d912db1f95dce6eb52d781dc210db5 (diff)
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Add m-esr52 at 52.6.0
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diff --git a/js/src/irregexp/RegExpEngine.cpp b/js/src/irregexp/RegExpEngine.cpp
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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ * vim: set ts=8 sts=4 et sw=4 tw=99: */
+
+// Copyright 2012 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+// * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following
+// disclaimer in the documentation and/or other materials provided
+// with the distribution.
+// * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived
+// from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include "irregexp/RegExpEngine.h"
+
+#include "irregexp/NativeRegExpMacroAssembler.h"
+#include "irregexp/RegExpMacroAssembler.h"
+#include "jit/ExecutableAllocator.h"
+#include "jit/JitCommon.h"
+
+using namespace js;
+using namespace js::irregexp;
+
+using mozilla::ArrayLength;
+using mozilla::DebugOnly;
+using mozilla::Maybe;
+
+#define DEFINE_ACCEPT(Type) \
+ void Type##Node::Accept(NodeVisitor* visitor) { \
+ visitor->Visit##Type(this); \
+ }
+FOR_EACH_NODE_TYPE(DEFINE_ACCEPT)
+#undef DEFINE_ACCEPT
+
+void LoopChoiceNode::Accept(NodeVisitor* visitor) {
+ visitor->VisitLoopChoice(this);
+}
+
+static const int kMaxLookaheadForBoyerMoore = 8;
+
+RegExpNode::RegExpNode(LifoAlloc* alloc)
+ : replacement_(nullptr), trace_count_(0), alloc_(alloc)
+{
+ bm_info_[0] = bm_info_[1] = nullptr;
+}
+
+// -------------------------------------------------------------------
+// CharacterRange
+
+// The '2' variant has inclusive from and exclusive to.
+// This covers \s as defined in ECMA-262 5.1, 15.10.2.12,
+// which include WhiteSpace (7.2) or LineTerminator (7.3) values.
+static const int kSpaceRanges[] = { '\t', '\r' + 1, ' ', ' ' + 1,
+ 0x00A0, 0x00A1, 0x1680, 0x1681, 0x180E, 0x180F, 0x2000, 0x200B,
+ 0x2028, 0x202A, 0x202F, 0x2030, 0x205F, 0x2060, 0x3000, 0x3001,
+ 0xFEFF, 0xFF00, 0x10000 };
+static const int kSpaceRangeCount = ArrayLength(kSpaceRanges);
+
+static const int kSpaceAndSurrogateRanges[] = { '\t', '\r' + 1, ' ', ' ' + 1,
+ 0x00A0, 0x00A1, 0x1680, 0x1681, 0x180E, 0x180F, 0x2000, 0x200B,
+ 0x2028, 0x202A, 0x202F, 0x2030, 0x205F, 0x2060, 0x3000, 0x3001,
+ unicode::LeadSurrogateMin, unicode::TrailSurrogateMax + 1,
+ 0xFEFF, 0xFF00, 0x10000 };
+static const int kSpaceAndSurrogateRangeCount = ArrayLength(kSpaceAndSurrogateRanges);
+static const int kWordRanges[] = {
+ '0', '9' + 1, 'A', 'Z' + 1, '_', '_' + 1, 'a', 'z' + 1, 0x10000 };
+static const int kWordRangeCount = ArrayLength(kWordRanges);
+static const int kIgnoreCaseWordRanges[] = {
+ '0', '9' + 1, 'A', 'Z' + 1, '_', '_' + 1, 'a', 'z' + 1,
+ 0x017F, 0x017F + 1, 0x212A, 0x212A + 1,
+ 0x10000 };
+static const int kIgnoreCaseWordCount = ArrayLength(kIgnoreCaseWordRanges);
+static const int kWordAndSurrogateRanges[] = {
+ '0', '9' + 1, 'A', 'Z' + 1, '_', '_' + 1, 'a', 'z' + 1,
+ unicode::LeadSurrogateMin, unicode::TrailSurrogateMax + 1,
+ 0x10000 };
+static const int kWordAndSurrogateRangeCount = ArrayLength(kWordAndSurrogateRanges);
+static const int kNegatedIgnoreCaseWordAndSurrogateRanges[] = {
+ 0, '0', '9' + 1, 'A',
+ 'Z' + 1, '_', '_' + 1, 'a',
+ 'z' + 1, 0x017F,
+ 0x017F + 1, 0x212A,
+ 0x212A + 1, unicode::LeadSurrogateMin,
+ unicode::TrailSurrogateMax + 1, 0x10000,
+ 0x10000 };
+static const int kNegatedIgnoreCaseWordAndSurrogateRangeCount =
+ ArrayLength(kNegatedIgnoreCaseWordAndSurrogateRanges);
+static const int kDigitRanges[] = { '0', '9' + 1, 0x10000 };
+static const int kDigitRangeCount = ArrayLength(kDigitRanges);
+static const int kDigitAndSurrogateRanges[] = {
+ '0', '9' + 1,
+ unicode::LeadSurrogateMin, unicode::TrailSurrogateMax + 1,
+ 0x10000 };
+static const int kDigitAndSurrogateRangeCount = ArrayLength(kDigitAndSurrogateRanges);
+static const int kSurrogateRanges[] = {
+ unicode::LeadSurrogateMin, unicode::TrailSurrogateMax + 1,
+ 0x10000 };
+static const int kSurrogateRangeCount = ArrayLength(kSurrogateRanges);
+static const int kLineTerminatorRanges[] = { 0x000A, 0x000B, 0x000D, 0x000E,
+ 0x2028, 0x202A, 0x10000 };
+static const int kLineTerminatorRangeCount = ArrayLength(kLineTerminatorRanges);
+static const int kMaxOneByteCharCode = 0xff;
+static const int kMaxUtf16CodeUnit = 0xffff;
+
+static char16_t
+MaximumCharacter(bool ascii)
+{
+ return ascii ? kMaxOneByteCharCode : kMaxUtf16CodeUnit;
+}
+
+static void
+AddClass(const int* elmv, int elmc,
+ CharacterRangeVector* ranges)
+{
+ elmc--;
+ MOZ_ASSERT(elmv[elmc] == 0x10000);
+ for (int i = 0; i < elmc; i += 2) {
+ MOZ_ASSERT(elmv[i] < elmv[i + 1]);
+ ranges->append(CharacterRange(elmv[i], elmv[i + 1] - 1));
+ }
+}
+
+static void
+AddClassNegated(const int* elmv,
+ int elmc,
+ CharacterRangeVector* ranges)
+{
+ elmc--;
+ MOZ_ASSERT(elmv[elmc] == 0x10000);
+ MOZ_ASSERT(elmv[0] != 0x0000);
+ MOZ_ASSERT(elmv[elmc-1] != kMaxUtf16CodeUnit);
+ char16_t last = 0x0000;
+ for (int i = 0; i < elmc; i += 2) {
+ MOZ_ASSERT(last <= elmv[i] - 1);
+ MOZ_ASSERT(elmv[i] < elmv[i + 1]);
+ ranges->append(CharacterRange(last, elmv[i] - 1));
+ last = elmv[i + 1];
+ }
+ ranges->append(CharacterRange(last, kMaxUtf16CodeUnit));
+}
+
+void
+CharacterRange::AddClassEscape(LifoAlloc* alloc, char16_t type,
+ CharacterRangeVector* ranges)
+{
+ switch (type) {
+ case 's':
+ AddClass(kSpaceRanges, kSpaceRangeCount, ranges);
+ break;
+ case 'S':
+ AddClassNegated(kSpaceRanges, kSpaceRangeCount, ranges);
+ break;
+ case 'w':
+ AddClass(kWordRanges, kWordRangeCount, ranges);
+ break;
+ case 'W':
+ AddClassNegated(kWordRanges, kWordRangeCount, ranges);
+ break;
+ case 'd':
+ AddClass(kDigitRanges, kDigitRangeCount, ranges);
+ break;
+ case 'D':
+ AddClassNegated(kDigitRanges, kDigitRangeCount, ranges);
+ break;
+ case '.':
+ AddClassNegated(kLineTerminatorRanges, kLineTerminatorRangeCount, ranges);
+ 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 '*':
+ ranges->append(CharacterRange::Everything());
+ break;
+ // This is the set of characters matched by the $ and ^ symbols
+ // in multiline mode.
+ case 'n':
+ AddClass(kLineTerminatorRanges, kLineTerminatorRangeCount, ranges);
+ break;
+ default:
+ MOZ_CRASH("Bad character class escape");
+ }
+}
+
+// Add class escape, excluding surrogate pair range.
+void
+CharacterRange::AddClassEscapeUnicode(LifoAlloc* alloc, char16_t type,
+ CharacterRangeVector* ranges, bool ignore_case)
+{
+ switch (type) {
+ case 's':
+ case 'd':
+ return AddClassEscape(alloc, type, ranges);
+ break;
+ case 'S':
+ AddClassNegated(kSpaceAndSurrogateRanges, kSpaceAndSurrogateRangeCount, ranges);
+ break;
+ case 'w':
+ if (ignore_case)
+ AddClass(kIgnoreCaseWordRanges, kIgnoreCaseWordCount, ranges);
+ else
+ AddClassEscape(alloc, type, ranges);
+ break;
+ case 'W':
+ if (ignore_case) {
+ AddClass(kNegatedIgnoreCaseWordAndSurrogateRanges,
+ kNegatedIgnoreCaseWordAndSurrogateRangeCount, ranges);
+ } else {
+ AddClassNegated(kWordAndSurrogateRanges, kWordAndSurrogateRangeCount, ranges);
+ }
+ break;
+ case 'D':
+ AddClassNegated(kDigitAndSurrogateRanges, kDigitAndSurrogateRangeCount, ranges);
+ break;
+ default:
+ MOZ_CRASH("Bad type!");
+ }
+}
+
+#define FOR_EACH_NON_ASCII_TO_ASCII_FOLDING(macro) \
+ /* LATIN CAPITAL LETTER Y WITH DIAERESIS */ \
+ macro(0x0178, 0x00FF) \
+ /* LATIN SMALL LETTER LONG S */ \
+ macro(0x017F, 0x0073) \
+ /* LATIN CAPITAL LETTER SHARP S */ \
+ macro(0x1E9E, 0x00DF) \
+ /* KELVIN SIGN */ \
+ macro(0x212A, 0x006B) \
+ /* ANGSTROM SIGN */ \
+ macro(0x212B, 0x00E5)
+
+// We need to check for the following characters: 0x39c 0x3bc 0x178.
+static inline bool
+RangeContainsLatin1Equivalents(CharacterRange range, bool unicode)
+{
+ /* TODO(dcarney): this could be a lot more efficient. */
+ if (unicode) {
+#define CHECK_RANGE(C, F) \
+ if (range.Contains(C)) return true;
+FOR_EACH_NON_ASCII_TO_ASCII_FOLDING(CHECK_RANGE)
+#undef CHECK_RANGE
+ }
+
+ return range.Contains(0x39c) || range.Contains(0x3bc) || range.Contains(0x178);
+}
+
+static bool
+RangesContainLatin1Equivalents(const CharacterRangeVector& ranges, bool unicode)
+{
+ for (size_t i = 0; i < ranges.length(); i++) {
+ // TODO(dcarney): this could be a lot more efficient.
+ if (RangeContainsLatin1Equivalents(ranges[i], unicode))
+ return true;
+ }
+ return false;
+}
+
+static const size_t kEcma262UnCanonicalizeMaxWidth = 4;
+
+// Returns the number of characters in the equivalence class, omitting those
+// that cannot occur in the source string if it is a one byte string.
+static int
+GetCaseIndependentLetters(char16_t character,
+ bool ascii_subject,
+ bool unicode,
+ const char16_t* choices,
+ size_t choices_length,
+ char16_t* letters)
+{
+ size_t count = 0;
+ for (size_t i = 0; i < choices_length; i++) {
+ char16_t c = choices[i];
+
+ // Skip characters that can't appear in one byte strings.
+ if (!unicode && ascii_subject && c > kMaxOneByteCharCode)
+ continue;
+
+ // Watch for duplicates.
+ bool found = false;
+ for (size_t j = 0; j < count; j++) {
+ if (letters[j] == c) {
+ found = true;
+ break;
+ }
+ }
+ if (found)
+ continue;
+
+ letters[count++] = c;
+ }
+
+ return count;
+}
+
+static int
+GetCaseIndependentLetters(char16_t character,
+ bool ascii_subject,
+ bool unicode,
+ char16_t* letters)
+{
+ if (unicode) {
+ const char16_t choices[] = {
+ character,
+ unicode::FoldCase(character),
+ unicode::ReverseFoldCase1(character),
+ unicode::ReverseFoldCase2(character),
+ unicode::ReverseFoldCase3(character),
+ };
+ return GetCaseIndependentLetters(character, ascii_subject, unicode,
+ choices, ArrayLength(choices), letters);
+ }
+
+ char16_t upper = unicode::ToUpperCase(character);
+ unicode::CodepointsWithSameUpperCase others(character);
+ char16_t other1 = others.other1();
+ char16_t other2 = others.other2();
+ char16_t other3 = others.other3();
+
+ // ES 2017 draft 996af87b7072b3c3dd2b1def856c66f456102215 21.2.4.2
+ // step 3.g.
+ // The standard requires that non-ASCII characters cannot have ASCII
+ // character codes in their equivalence class, even though this
+ // situation occurs multiple times in the unicode tables.
+ static const unsigned kMaxAsciiCharCode = 127;
+ if (upper <= kMaxAsciiCharCode) {
+ if (character > kMaxAsciiCharCode) {
+ // If Canonicalize(character) == character, all other characters
+ // should be ignored.
+ return GetCaseIndependentLetters(character, ascii_subject, unicode,
+ &character, 1, letters);
+ }
+
+ if (other1 > kMaxAsciiCharCode)
+ other1 = character;
+ if (other2 > kMaxAsciiCharCode)
+ other2 = character;
+ if (other3 > kMaxAsciiCharCode)
+ other3 = character;
+ }
+
+ const char16_t choices[] = {
+ character,
+ upper,
+ other1,
+ other2,
+ other3
+ };
+ return GetCaseIndependentLetters(character, ascii_subject, unicode,
+ choices, ArrayLength(choices), letters);
+}
+
+static char16_t
+ConvertNonLatin1ToLatin1(char16_t c, bool unicode)
+{
+ MOZ_ASSERT(c > kMaxOneByteCharCode);
+ if (unicode) {
+ switch (c) {
+#define CONVERT(C, F) case C: return F;
+FOR_EACH_NON_ASCII_TO_ASCII_FOLDING(CONVERT)
+#undef CONVERT
+ }
+ }
+
+ switch (c) {
+ // This are equivalent characters in unicode.
+ case 0x39c:
+ case 0x3bc:
+ return 0xb5;
+ // This is an uppercase of a Latin-1 character
+ // outside of Latin-1.
+ case 0x178:
+ return 0xff;
+ }
+ return 0;
+}
+
+void
+CharacterRange::AddCaseEquivalents(bool is_ascii, bool unicode, CharacterRangeVector* ranges)
+{
+ char16_t bottom = from();
+ char16_t top = to();
+
+ if (is_ascii && !RangeContainsLatin1Equivalents(*this, unicode)) {
+ if (bottom > kMaxOneByteCharCode)
+ return;
+ if (top > kMaxOneByteCharCode)
+ top = kMaxOneByteCharCode;
+ }
+
+ for (char16_t c = bottom;; c++) {
+ char16_t chars[kEcma262UnCanonicalizeMaxWidth];
+ size_t length = GetCaseIndependentLetters(c, is_ascii, unicode, chars);
+
+ for (size_t i = 0; i < length; i++) {
+ char16_t other = chars[i];
+ if (other == c)
+ continue;
+
+ // Try to combine with an existing range.
+ bool found = false;
+ for (size_t i = 0; i < ranges->length(); i++) {
+ CharacterRange& range = (*ranges)[i];
+ if (range.Contains(other)) {
+ found = true;
+ break;
+ } else if (other == range.from() - 1) {
+ range.set_from(other);
+ found = true;
+ break;
+ } else if (other == range.to() + 1) {
+ range.set_to(other);
+ found = true;
+ break;
+ }
+ }
+
+ if (!found)
+ ranges->append(CharacterRange::Singleton(other));
+ }
+
+ if (c == top)
+ break;
+ }
+}
+
+static bool
+CompareInverseRanges(const CharacterRangeVector& ranges, const int* special_class, size_t length)
+{
+ length--; // Remove final 0x10000.
+ MOZ_ASSERT(special_class[length] == 0x10000);
+ MOZ_ASSERT(ranges.length() != 0);
+ MOZ_ASSERT(length != 0);
+ MOZ_ASSERT(special_class[0] != 0);
+ if (ranges.length() != (length >> 1) + 1)
+ return false;
+ CharacterRange range = ranges[0];
+ if (range.from() != 0)
+ return false;
+ for (size_t i = 0; i < length; i += 2) {
+ if (special_class[i] != (range.to() + 1))
+ return false;
+ range = ranges[(i >> 1) + 1];
+ if (special_class[i+1] != range.from())
+ return false;
+ }
+ if (range.to() != 0xffff)
+ return false;
+ return true;
+}
+
+static bool
+CompareRanges(const CharacterRangeVector& ranges, const int* special_class, size_t length)
+{
+ length--; // Remove final 0x10000.
+ MOZ_ASSERT(special_class[length] == 0x10000);
+ if (ranges.length() * 2 != length)
+ return false;
+ for (size_t i = 0; i < length; i += 2) {
+ CharacterRange range = ranges[i >> 1];
+ if (range.from() != special_class[i] || range.to() != special_class[i + 1] - 1)
+ return false;
+ }
+ return true;
+}
+
+bool
+RegExpCharacterClass::is_standard(LifoAlloc* alloc)
+{
+ // 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(alloc), kSpaceRanges, kSpaceRangeCount)) {
+ set_.set_standard_set_type('s');
+ return true;
+ }
+ if (CompareInverseRanges(set_.ranges(alloc), kSpaceRanges, kSpaceRangeCount)) {
+ set_.set_standard_set_type('S');
+ return true;
+ }
+ if (CompareInverseRanges(set_.ranges(alloc),
+ kLineTerminatorRanges,
+ kLineTerminatorRangeCount)) {
+ set_.set_standard_set_type('.');
+ return true;
+ }
+ if (CompareRanges(set_.ranges(alloc),
+ kLineTerminatorRanges,
+ kLineTerminatorRangeCount)) {
+ set_.set_standard_set_type('n');
+ return true;
+ }
+ if (CompareRanges(set_.ranges(alloc), kWordRanges, kWordRangeCount)) {
+ set_.set_standard_set_type('w');
+ return true;
+ }
+ if (CompareInverseRanges(set_.ranges(alloc), kWordRanges, kWordRangeCount)) {
+ set_.set_standard_set_type('W');
+ return true;
+ }
+ return false;
+}
+
+bool
+CharacterRange::IsCanonical(const CharacterRangeVector& ranges)
+{
+ int n = ranges.length();
+ if (n <= 1)
+ return true;
+
+ int max = ranges[0].to();
+ for (int i = 1; i < n; i++) {
+ CharacterRange next_range = ranges[i];
+ if (next_range.from() <= max + 1)
+ return false;
+ max = next_range.to();
+ }
+ return true;
+}
+
+// Move a number of elements in a zonelist to another position
+// in the same list. Handles overlapping source and target areas.
+static
+void MoveRanges(CharacterRangeVector& list, int from, int to, int count)
+{
+ // Ranges are potentially overlapping.
+ if (from < to) {
+ for (int i = count - 1; i >= 0; i--)
+ list[to + i] = list[from + i];
+ } else {
+ for (int i = 0; i < count; i++)
+ list[to + i] = list[from + i];
+ }
+}
+
+static int
+InsertRangeInCanonicalList(CharacterRangeVector& 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.
+ char16_t from = insert.from();
+ char16_t to = insert.to();
+ int start_pos = 0;
+ int end_pos = count;
+ for (int i = count - 1; i >= 0; i--) {
+ CharacterRange current = list[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[start_pos] = insert;
+ return count + 1;
+ }
+ if (start_pos + 1 == end_pos) {
+ // Replace single existing range at position start_pos.
+ CharacterRange to_replace = list[start_pos];
+ int new_from = Min(to_replace.from(), from);
+ int new_to = Max(to_replace.to(), to);
+ list[start_pos] = CharacterRange(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 = Min(list[start_pos].from(), from);
+ int new_to = Max(list[end_pos - 1].to(), to);
+ if (end_pos < count) {
+ MoveRanges(list, end_pos, start_pos + 1, count - end_pos);
+ }
+ list[start_pos] = CharacterRange(new_from, new_to);
+ return count - (end_pos - start_pos) + 1;
+}
+
+void
+CharacterRange::Canonicalize(CharacterRangeVector& character_ranges)
+{
+ if (character_ranges.length() <= 1) return;
+ // Check whether ranges are already canonical (increasing, non-overlapping,
+ // non-adjacent).
+ int n = character_ranges.length();
+ int max = character_ranges[0].to();
+ int i = 1;
+ while (i < n) {
+ CharacterRange current = character_ranges[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.
+ size_t num_canonical = i; // Length of canonicalized part of list.
+ do {
+ num_canonical = InsertRangeInCanonicalList(character_ranges,
+ num_canonical,
+ character_ranges[read]);
+ read++;
+ } while (read < n);
+
+ while (character_ranges.length() > num_canonical)
+ character_ranges.popBack();
+
+ MOZ_ASSERT(CharacterRange::IsCanonical(character_ranges));
+}
+
+// -------------------------------------------------------------------
+// SeqRegExpNode
+
+class VisitMarker
+{
+ public:
+ explicit VisitMarker(NodeInfo* info)
+ : info_(info)
+ {
+ MOZ_ASSERT(!info->visited);
+ info->visited = true;
+ }
+ ~VisitMarker() {
+ info_->visited = false;
+ }
+ private:
+ NodeInfo* info_;
+};
+
+bool
+SeqRegExpNode::FillInBMInfo(int offset,
+ int budget,
+ BoyerMooreLookahead* bm,
+ bool not_at_start)
+{
+ if (!bm->CheckOverRecursed())
+ return false;
+ if (!on_success_->FillInBMInfo(offset, budget - 1, bm, not_at_start))
+ return false;
+ if (offset == 0)
+ set_bm_info(not_at_start, bm);
+ return true;
+}
+
+RegExpNode*
+SeqRegExpNode::FilterASCII(int depth, bool ignore_case, bool unicode)
+{
+ if (info()->replacement_calculated)
+ return replacement();
+
+ if (depth < 0)
+ return this;
+
+ MOZ_ASSERT(!info()->visited);
+ VisitMarker marker(info());
+ return FilterSuccessor(depth - 1, ignore_case, unicode);
+}
+
+RegExpNode*
+SeqRegExpNode::FilterSuccessor(int depth, bool ignore_case, bool unicode)
+{
+ RegExpNode* next = on_success_->FilterASCII(depth - 1, ignore_case, unicode);
+ if (next == nullptr)
+ return set_replacement(nullptr);
+
+ on_success_ = next;
+ return set_replacement(this);
+}
+
+// -------------------------------------------------------------------
+// ActionNode
+
+int
+ActionNode::EatsAtLeast(int still_to_find, int budget, bool not_at_start)
+{
+ if (budget <= 0)
+ return 0;
+ if (action_type_ == POSITIVE_SUBMATCH_SUCCESS)
+ return 0; // Rewinds input!
+ return on_success()->EatsAtLeast(still_to_find,
+ budget - 1,
+ not_at_start);
+}
+
+bool
+ActionNode::FillInBMInfo(int offset,
+ int budget,
+ BoyerMooreLookahead* bm,
+ bool not_at_start)
+{
+ if (!bm->CheckOverRecursed())
+ return false;
+
+ if (action_type_ == BEGIN_SUBMATCH) {
+ bm->SetRest(offset);
+ } else if (action_type_ != POSITIVE_SUBMATCH_SUCCESS) {
+ if (!on_success()->FillInBMInfo(offset, budget - 1, bm, not_at_start))
+ return false;
+ }
+ SaveBMInfo(bm, not_at_start, offset);
+
+ return true;
+}
+
+/* static */ ActionNode*
+ActionNode::SetRegister(int reg,
+ int val,
+ RegExpNode* on_success)
+{
+ ActionNode* result = on_success->alloc()->newInfallible<ActionNode>(SET_REGISTER, on_success);
+ result->data_.u_store_register.reg = reg;
+ result->data_.u_store_register.value = val;
+ return result;
+}
+
+/* static */ ActionNode*
+ActionNode::IncrementRegister(int reg, RegExpNode* on_success)
+{
+ ActionNode* result = on_success->alloc()->newInfallible<ActionNode>(INCREMENT_REGISTER, on_success);
+ result->data_.u_increment_register.reg = reg;
+ return result;
+}
+
+/* static */ ActionNode*
+ActionNode::StorePosition(int reg, bool is_capture, RegExpNode* on_success)
+{
+ ActionNode* result = on_success->alloc()->newInfallible<ActionNode>(STORE_POSITION, on_success);
+ result->data_.u_position_register.reg = reg;
+ result->data_.u_position_register.is_capture = is_capture;
+ return result;
+}
+
+/* static */ ActionNode*
+ActionNode::ClearCaptures(Interval range, RegExpNode* on_success)
+{
+ ActionNode* result = on_success->alloc()->newInfallible<ActionNode>(CLEAR_CAPTURES, on_success);
+ result->data_.u_clear_captures.range_from = range.from();
+ result->data_.u_clear_captures.range_to = range.to();
+ return result;
+}
+
+/* static */ ActionNode*
+ActionNode::BeginSubmatch(int stack_pointer_reg, int position_reg, RegExpNode* on_success)
+{
+ ActionNode* result = on_success->alloc()->newInfallible<ActionNode>(BEGIN_SUBMATCH, on_success);
+ result->data_.u_submatch.stack_pointer_register = stack_pointer_reg;
+ result->data_.u_submatch.current_position_register = position_reg;
+ return result;
+}
+
+/* static */ ActionNode*
+ActionNode::PositiveSubmatchSuccess(int stack_pointer_reg,
+ int restore_reg,
+ int clear_capture_count,
+ int clear_capture_from,
+ RegExpNode* on_success)
+{
+ ActionNode* result = on_success->alloc()->newInfallible<ActionNode>(POSITIVE_SUBMATCH_SUCCESS, on_success);
+ result->data_.u_submatch.stack_pointer_register = stack_pointer_reg;
+ result->data_.u_submatch.current_position_register = restore_reg;
+ result->data_.u_submatch.clear_register_count = clear_capture_count;
+ result->data_.u_submatch.clear_register_from = clear_capture_from;
+ return result;
+}
+
+/* static */ ActionNode*
+ActionNode::EmptyMatchCheck(int start_register,
+ int repetition_register,
+ int repetition_limit,
+ RegExpNode* on_success)
+{
+ ActionNode* result = on_success->alloc()->newInfallible<ActionNode>(EMPTY_MATCH_CHECK, on_success);
+ result->data_.u_empty_match_check.start_register = start_register;
+ result->data_.u_empty_match_check.repetition_register = repetition_register;
+ result->data_.u_empty_match_check.repetition_limit = repetition_limit;
+ return result;
+}
+
+// -------------------------------------------------------------------
+// TextNode
+
+int
+TextNode::EatsAtLeast(int still_to_find, int budget, bool not_at_start)
+{
+ int answer = Length();
+ if (answer >= still_to_find)
+ return answer;
+ if (budget <= 0)
+ return answer;
+
+ // We are not at start after this node so we set the last argument to 'true'.
+ return answer + on_success()->EatsAtLeast(still_to_find - answer,
+ budget - 1,
+ true);
+}
+
+int
+TextNode::GreedyLoopTextLength()
+{
+ TextElement elm = elements()[elements().length() - 1];
+ return elm.cp_offset() + elm.length();
+}
+
+RegExpNode*
+TextNode::FilterASCII(int depth, bool ignore_case, bool unicode)
+{
+ if (info()->replacement_calculated)
+ return replacement();
+
+ if (depth < 0)
+ return this;
+
+ MOZ_ASSERT(!info()->visited);
+ VisitMarker marker(info());
+ int element_count = elements().length();
+ for (int i = 0; i < element_count; i++) {
+ TextElement elm = elements()[i];
+ if (elm.text_type() == TextElement::ATOM) {
+ CharacterVector& quarks = const_cast<CharacterVector&>(elm.atom()->data());
+ for (size_t j = 0; j < quarks.length(); j++) {
+ uint16_t c = quarks[j];
+ if (c <= kMaxOneByteCharCode)
+ continue;
+ if (!ignore_case)
+ return set_replacement(nullptr);
+
+ // Here, we need to check for characters whose upper and lower cases
+ // are outside the Latin-1 range.
+ char16_t converted = ConvertNonLatin1ToLatin1(c, unicode);
+ if (converted == 0) {
+ // Character is outside Latin-1 completely
+ return set_replacement(nullptr);
+ }
+
+ // Convert quark to Latin-1 in place.
+ quarks[j] = converted;
+ }
+ } else {
+ MOZ_ASSERT(elm.text_type() == TextElement::CHAR_CLASS);
+ RegExpCharacterClass* cc = elm.char_class();
+
+ CharacterRangeVector& ranges = cc->ranges(alloc());
+ if (!CharacterRange::IsCanonical(ranges))
+ CharacterRange::Canonicalize(ranges);
+
+ // Now they are in order so we only need to look at the first.
+ int range_count = ranges.length();
+ if (cc->is_negated()) {
+ if (range_count != 0 &&
+ ranges[0].from() == 0 &&
+ ranges[0].to() >= kMaxOneByteCharCode)
+ {
+ // This will be handled in a later filter.
+ if (ignore_case && RangesContainLatin1Equivalents(ranges, unicode))
+ continue;
+ return set_replacement(nullptr);
+ }
+ } else {
+ if (range_count == 0 ||
+ ranges[0].from() > kMaxOneByteCharCode)
+ {
+ // This will be handled in a later filter.
+ if (ignore_case && RangesContainLatin1Equivalents(ranges, unicode))
+ continue;
+ return set_replacement(nullptr);
+ }
+ }
+ }
+ }
+ return FilterSuccessor(depth - 1, ignore_case, unicode);
+}
+
+void
+TextNode::CalculateOffsets()
+{
+ int element_count = elements().length();
+
+ // Set up the offsets of the elements relative to the start. This is a fixed
+ // quantity since a TextNode can only contain fixed-width things.
+ int cp_offset = 0;
+ for (int i = 0; i < element_count; i++) {
+ TextElement& elm = elements()[i];
+ elm.set_cp_offset(cp_offset);
+ cp_offset += elm.length();
+ }
+}
+
+void TextNode::MakeCaseIndependent(bool is_ascii, bool unicode)
+{
+ int element_count = elements().length();
+ for (int i = 0; i < element_count; i++) {
+ TextElement elm = elements()[i];
+ if (elm.text_type() == TextElement::CHAR_CLASS) {
+ RegExpCharacterClass* cc = elm.char_class();
+
+ // None of the standard character classes is different in the case
+ // independent case and it slows us down if we don't know that.
+ if (cc->is_standard(alloc()))
+ continue;
+
+ CharacterRangeVector& ranges = cc->ranges(alloc());
+ int range_count = ranges.length();
+ for (int j = 0; j < range_count; j++)
+ ranges[j].AddCaseEquivalents(is_ascii, unicode, &ranges);
+ }
+ }
+}
+
+// -------------------------------------------------------------------
+// AssertionNode
+
+int
+AssertionNode::EatsAtLeast(int still_to_find, int budget, bool not_at_start)
+{
+ if (budget <= 0)
+ return 0;
+
+ // If we know we are not at the start and we are asked "how many characters
+ // will you match if you succeed?" then we can answer anything since false
+ // implies false. So lets just return the max answer (still_to_find) since
+ // that won't prevent us from preloading a lot of characters for the other
+ // branches in the node graph.
+ if (assertion_type() == AT_START && not_at_start)
+ return still_to_find;
+
+ return on_success()->EatsAtLeast(still_to_find, budget - 1, not_at_start);
+}
+
+bool
+AssertionNode::FillInBMInfo(int offset, int budget, BoyerMooreLookahead* bm, bool not_at_start)
+{
+ if (!bm->CheckOverRecursed())
+ return false;
+
+ // Match the behaviour of EatsAtLeast on this node.
+ if (assertion_type() == AT_START && not_at_start)
+ return true;
+
+ if (!on_success()->FillInBMInfo(offset, budget - 1, bm, not_at_start))
+ return false;
+ SaveBMInfo(bm, not_at_start, offset);
+ return true;
+}
+
+// -------------------------------------------------------------------
+// BackReferenceNode
+
+int
+BackReferenceNode::EatsAtLeast(int still_to_find, int budget, bool not_at_start)
+{
+ if (budget <= 0)
+ return 0;
+ return on_success()->EatsAtLeast(still_to_find, budget - 1, not_at_start);
+}
+
+bool
+BackReferenceNode::FillInBMInfo(int offset, int budget, BoyerMooreLookahead* bm, bool not_at_start)
+{
+ // Working out the set of characters that a backreference can match is too
+ // hard, so we just say that any character can match.
+ bm->SetRest(offset);
+ SaveBMInfo(bm, not_at_start, offset);
+ return true;
+}
+
+// -------------------------------------------------------------------
+// ChoiceNode
+
+int
+ChoiceNode::EatsAtLeastHelper(int still_to_find,
+ int budget,
+ RegExpNode* ignore_this_node,
+ bool not_at_start)
+{
+ if (budget <= 0)
+ return 0;
+
+ int min = 100;
+ size_t choice_count = alternatives().length();
+ budget = (budget - 1) / choice_count;
+ for (size_t i = 0; i < choice_count; i++) {
+ RegExpNode* node = alternatives()[i].node();
+ if (node == ignore_this_node) continue;
+ int node_eats_at_least =
+ node->EatsAtLeast(still_to_find, budget, not_at_start);
+ if (node_eats_at_least < min)
+ min = node_eats_at_least;
+ if (min == 0)
+ return 0;
+ }
+ return min;
+}
+
+int
+ChoiceNode::EatsAtLeast(int still_to_find, int budget, bool not_at_start)
+{
+ return EatsAtLeastHelper(still_to_find,
+ budget,
+ nullptr,
+ not_at_start);
+}
+
+void
+ChoiceNode::GetQuickCheckDetails(QuickCheckDetails* details,
+ RegExpCompiler* compiler,
+ int characters_filled_in,
+ bool not_at_start)
+{
+ not_at_start = (not_at_start || not_at_start_);
+ int choice_count = alternatives().length();
+ MOZ_ASSERT(choice_count > 0);
+ alternatives()[0].node()->GetQuickCheckDetails(details,
+ compiler,
+ characters_filled_in,
+ not_at_start);
+ for (int i = 1; i < choice_count; i++) {
+ QuickCheckDetails new_details(details->characters());
+ RegExpNode* node = alternatives()[i].node();
+ node->GetQuickCheckDetails(&new_details, compiler,
+ characters_filled_in,
+ not_at_start);
+ // Here we merge the quick match details of the two branches.
+ details->Merge(&new_details, characters_filled_in);
+ }
+}
+
+bool
+ChoiceNode::FillInBMInfo(int offset,
+ int budget,
+ BoyerMooreLookahead* bm,
+ bool not_at_start)
+{
+ if (!bm->CheckOverRecursed())
+ return false;
+
+ const GuardedAlternativeVector& alts = alternatives();
+ budget = (budget - 1) / alts.length();
+ for (size_t i = 0; i < alts.length(); i++) {
+ const GuardedAlternative& alt = alts[i];
+ if (alt.guards() != nullptr && alt.guards()->length() != 0) {
+ bm->SetRest(offset); // Give up trying to fill in info.
+ SaveBMInfo(bm, not_at_start, offset);
+ return true;
+ }
+ if (!alt.node()->FillInBMInfo(offset, budget, bm, not_at_start))
+ return false;
+ }
+ SaveBMInfo(bm, not_at_start, offset);
+ return true;
+}
+
+RegExpNode*
+ChoiceNode::FilterASCII(int depth, bool ignore_case, bool unicode)
+{
+ if (info()->replacement_calculated)
+ return replacement();
+ if (depth < 0)
+ return this;
+ if (info()->visited)
+ return this;
+ VisitMarker marker(info());
+ int choice_count = alternatives().length();
+
+ for (int i = 0; i < choice_count; i++) {
+ const GuardedAlternative alternative = alternatives()[i];
+ if (alternative.guards() != nullptr && alternative.guards()->length() != 0) {
+ set_replacement(this);
+ return this;
+ }
+ }
+
+ int surviving = 0;
+ RegExpNode* survivor = nullptr;
+ for (int i = 0; i < choice_count; i++) {
+ GuardedAlternative alternative = alternatives()[i];
+ RegExpNode* replacement =
+ alternative.node()->FilterASCII(depth - 1, ignore_case, unicode);
+ MOZ_ASSERT(replacement != this); // No missing EMPTY_MATCH_CHECK.
+ if (replacement != nullptr) {
+ alternatives()[i].set_node(replacement);
+ surviving++;
+ survivor = replacement;
+ }
+ }
+ if (surviving < 2)
+ return set_replacement(survivor);
+
+ set_replacement(this);
+ if (surviving == choice_count)
+ return this;
+
+ // Only some of the nodes survived the filtering. We need to rebuild the
+ // alternatives list.
+ GuardedAlternativeVector new_alternatives(*alloc());
+ new_alternatives.reserve(surviving);
+ for (int i = 0; i < choice_count; i++) {
+ RegExpNode* replacement =
+ alternatives()[i].node()->FilterASCII(depth - 1, ignore_case, unicode);
+ if (replacement != nullptr) {
+ alternatives()[i].set_node(replacement);
+ new_alternatives.append(alternatives()[i]);
+ }
+ }
+
+ alternatives_ = Move(new_alternatives);
+ return this;
+}
+
+// -------------------------------------------------------------------
+// NegativeLookaheadChoiceNode
+
+bool
+NegativeLookaheadChoiceNode::FillInBMInfo(int offset,
+ int budget,
+ BoyerMooreLookahead* bm,
+ bool not_at_start)
+{
+ if (!bm->CheckOverRecursed())
+ return false;
+
+ if (!alternatives()[1].node()->FillInBMInfo(offset, budget - 1, bm, not_at_start))
+ return false;
+ if (offset == 0)
+ set_bm_info(not_at_start, bm);
+ return true;
+}
+
+int
+NegativeLookaheadChoiceNode::EatsAtLeast(int still_to_find, int budget, bool not_at_start)
+{
+ if (budget <= 0)
+ return 0;
+
+ // Alternative 0 is the negative lookahead, alternative 1 is what comes
+ // afterwards.
+ RegExpNode* node = alternatives()[1].node();
+ return node->EatsAtLeast(still_to_find, budget - 1, not_at_start);
+}
+
+void
+NegativeLookaheadChoiceNode::GetQuickCheckDetails(QuickCheckDetails* details,
+ RegExpCompiler* compiler,
+ int filled_in,
+ bool not_at_start)
+{
+ // Alternative 0 is the negative lookahead, alternative 1 is what comes
+ // afterwards.
+ RegExpNode* node = alternatives()[1].node();
+ return node->GetQuickCheckDetails(details, compiler, filled_in, not_at_start);
+}
+
+RegExpNode*
+NegativeLookaheadChoiceNode::FilterASCII(int depth, bool ignore_case, bool unicode)
+{
+ if (info()->replacement_calculated)
+ return replacement();
+ if (depth < 0)
+ return this;
+ if (info()->visited)
+ return this;
+
+ VisitMarker marker(info());
+
+ // Alternative 0 is the negative lookahead, alternative 1 is what comes
+ // afterwards.
+ RegExpNode* node = alternatives()[1].node();
+ RegExpNode* replacement = node->FilterASCII(depth - 1, ignore_case, unicode);
+
+ if (replacement == nullptr)
+ return set_replacement(nullptr);
+ alternatives()[1].set_node(replacement);
+
+ RegExpNode* neg_node = alternatives()[0].node();
+ RegExpNode* neg_replacement = neg_node->FilterASCII(depth - 1, ignore_case, unicode);
+
+ // If the negative lookahead is always going to fail then
+ // we don't need to check it.
+ if (neg_replacement == nullptr)
+ return set_replacement(replacement);
+
+ alternatives()[0].set_node(neg_replacement);
+ return set_replacement(this);
+}
+
+// -------------------------------------------------------------------
+// LoopChoiceNode
+
+void
+GuardedAlternative::AddGuard(LifoAlloc* alloc, Guard* guard)
+{
+ if (guards_ == nullptr)
+ guards_ = alloc->newInfallible<GuardVector>(*alloc);
+ guards_->append(guard);
+}
+
+void
+LoopChoiceNode::AddLoopAlternative(GuardedAlternative alt)
+{
+ MOZ_ASSERT(loop_node_ == nullptr);
+ AddAlternative(alt);
+ loop_node_ = alt.node();
+}
+
+
+void
+LoopChoiceNode::AddContinueAlternative(GuardedAlternative alt)
+{
+ MOZ_ASSERT(continue_node_ == nullptr);
+ AddAlternative(alt);
+ continue_node_ = alt.node();
+}
+
+int
+LoopChoiceNode::EatsAtLeast(int still_to_find, int budget, bool not_at_start)
+{
+ return EatsAtLeastHelper(still_to_find,
+ budget - 1,
+ loop_node_,
+ not_at_start);
+}
+
+void
+LoopChoiceNode::GetQuickCheckDetails(QuickCheckDetails* details,
+ RegExpCompiler* compiler,
+ int characters_filled_in,
+ bool not_at_start)
+{
+ if (body_can_be_zero_length_ || info()->visited)
+ return;
+ VisitMarker marker(info());
+ return ChoiceNode::GetQuickCheckDetails(details,
+ compiler,
+ characters_filled_in,
+ not_at_start);
+}
+
+bool
+LoopChoiceNode::FillInBMInfo(int offset,
+ int budget,
+ BoyerMooreLookahead* bm,
+ bool not_at_start)
+{
+ if (body_can_be_zero_length_ || budget <= 0) {
+ bm->SetRest(offset);
+ SaveBMInfo(bm, not_at_start, offset);
+ return true;
+ }
+ if (!ChoiceNode::FillInBMInfo(offset, budget - 1, bm, not_at_start))
+ return false;
+ SaveBMInfo(bm, not_at_start, offset);
+ return true;
+}
+
+RegExpNode*
+LoopChoiceNode::FilterASCII(int depth, bool ignore_case, bool unicode)
+{
+ if (info()->replacement_calculated)
+ return replacement();
+ if (depth < 0)
+ return this;
+ if (info()->visited)
+ return this;
+
+ {
+ VisitMarker marker(info());
+
+ RegExpNode* continue_replacement =
+ continue_node_->FilterASCII(depth - 1, ignore_case, unicode);
+
+ // If we can't continue after the loop then there is no sense in doing the
+ // loop.
+ if (continue_replacement == nullptr)
+ return set_replacement(nullptr);
+ }
+
+ return ChoiceNode::FilterASCII(depth - 1, ignore_case, unicode);
+}
+
+// -------------------------------------------------------------------
+// Analysis
+
+void
+Analysis::EnsureAnalyzed(RegExpNode* that)
+{
+ JS_CHECK_RECURSION(cx, failASCII("Stack overflow"); return);
+
+ if (that->info()->been_analyzed || that->info()->being_analyzed)
+ return;
+ that->info()->being_analyzed = true;
+ that->Accept(this);
+ that->info()->being_analyzed = false;
+ that->info()->been_analyzed = true;
+}
+
+void
+Analysis::VisitEnd(EndNode* that)
+{
+ // nothing to do
+}
+
+void
+Analysis::VisitText(TextNode* that)
+{
+ if (ignore_case_)
+ that->MakeCaseIndependent(is_ascii_, unicode_);
+ EnsureAnalyzed(that->on_success());
+ if (!has_failed()) {
+ that->CalculateOffsets();
+ }
+}
+
+void
+Analysis::VisitAction(ActionNode* that)
+{
+ RegExpNode* target = that->on_success();
+ EnsureAnalyzed(target);
+
+ if (!has_failed()) {
+ // If the next node is interested in what it follows then this node
+ // has to be interested too so it can pass the information on.
+ that->info()->AddFromFollowing(target->info());
+ }
+}
+
+void
+Analysis::VisitChoice(ChoiceNode* that)
+{
+ NodeInfo* info = that->info();
+
+ for (size_t i = 0; i < that->alternatives().length(); i++) {
+ RegExpNode* node = that->alternatives()[i].node();
+ EnsureAnalyzed(node);
+ if (has_failed()) return;
+
+ // Anything the following nodes need to know has to be known by
+ // this node also, so it can pass it on.
+ info->AddFromFollowing(node->info());
+ }
+}
+
+void
+Analysis::VisitLoopChoice(LoopChoiceNode* that)
+{
+ NodeInfo* info = that->info();
+ for (size_t i = 0; i < that->alternatives().length(); i++) {
+ RegExpNode* node = that->alternatives()[i].node();
+ if (node != that->loop_node()) {
+ EnsureAnalyzed(node);
+ if (has_failed()) return;
+ info->AddFromFollowing(node->info());
+ }
+ }
+
+ // Check the loop last since it may need the value of this node
+ // to get a correct result.
+ EnsureAnalyzed(that->loop_node());
+ if (!has_failed())
+ info->AddFromFollowing(that->loop_node()->info());
+}
+
+void
+Analysis::VisitBackReference(BackReferenceNode* that)
+{
+ EnsureAnalyzed(that->on_success());
+}
+
+void
+Analysis::VisitAssertion(AssertionNode* that)
+{
+ EnsureAnalyzed(that->on_success());
+}
+
+// -------------------------------------------------------------------
+// Implementation of the Irregexp regular expression engine.
+//
+// The Irregexp regular expression engine is intended to be a complete
+// implementation of ECMAScript regular expressions. It generates either
+// bytecodes or native code.
+
+// The Irregexp regexp engine is structured in three steps.
+// 1) The parser generates an abstract syntax tree. See RegExpAST.cpp.
+// 2) From the AST a node network is created. The nodes are all
+// subclasses of RegExpNode. The nodes represent states when
+// executing a regular expression. Several optimizations are
+// performed on the node network.
+// 3) From the nodes we generate either byte codes or native code
+// that can actually execute the regular expression (perform
+// the search). The code generation step is described in more
+// detail below.
+
+// Code generation.
+//
+// The nodes are divided into four main categories.
+// * Choice nodes
+// These represent places where the regular expression can
+// match in more than one way. For example on entry to an
+// alternation (foo|bar) or a repetition (*, +, ? or {}).
+// * Action nodes
+// These represent places where some action should be
+// performed. Examples include recording the current position
+// in the input string to a register (in order to implement
+// captures) or other actions on register for example in order
+// to implement the counters needed for {} repetitions.
+// * Matching nodes
+// These attempt to match some element part of the input string.
+// Examples of elements include character classes, plain strings
+// or back references.
+// * End nodes
+// These are used to implement the actions required on finding
+// a successful match or failing to find a match.
+//
+// The code generated (whether as byte codes or native code) maintains
+// some state as it runs. This consists of the following elements:
+//
+// * The capture registers. Used for string captures.
+// * Other registers. Used for counters etc.
+// * The current position.
+// * The stack of backtracking information. Used when a matching node
+// fails to find a match and needs to try an alternative.
+//
+// Conceptual regular expression execution model:
+//
+// There is a simple conceptual model of regular expression execution
+// which will be presented first. The actual code generated is a more
+// efficient simulation of the simple conceptual model:
+//
+// * Choice nodes are implemented as follows:
+// For each choice except the last {
+// push current position
+// push backtrack code location
+// <generate code to test for choice>
+// backtrack code location:
+// pop current position
+// }
+// <generate code to test for last choice>
+//
+// * Actions nodes are generated as follows
+// <push affected registers on backtrack stack>
+// <generate code to perform action>
+// push backtrack code location
+// <generate code to test for following nodes>
+// backtrack code location:
+// <pop affected registers to restore their state>
+// <pop backtrack location from stack and go to it>
+//
+// * Matching nodes are generated as follows:
+// if input string matches at current position
+// update current position
+// <generate code to test for following nodes>
+// else
+// <pop backtrack location from stack and go to it>
+//
+// Thus it can be seen that the current position is saved and restored
+// by the choice nodes, whereas the registers are saved and restored by
+// by the action nodes that manipulate them.
+//
+// The other interesting aspect of this model is that nodes are generated
+// at the point where they are needed by a recursive call to Emit(). If
+// the node has already been code generated then the Emit() call will
+// generate a jump to the previously generated code instead. In order to
+// limit recursion it is possible for the Emit() function to put the node
+// on a work list for later generation and instead generate a jump. The
+// destination of the jump is resolved later when the code is generated.
+//
+// Actual regular expression code generation.
+//
+// Code generation is actually more complicated than the above. In order
+// to improve the efficiency of the generated code some optimizations are
+// performed
+//
+// * Choice nodes have 1-character lookahead.
+// A choice node looks at the following character and eliminates some of
+// the choices immediately based on that character. This is not yet
+// implemented.
+// * Simple greedy loops store reduced backtracking information.
+// A quantifier like /.*foo/m will greedily match the whole input. It will
+// then need to backtrack to a point where it can match "foo". The naive
+// implementation of this would push each character position onto the
+// backtracking stack, then pop them off one by one. This would use space
+// proportional to the length of the input string. However since the "."
+// can only match in one way and always has a constant length (in this case
+// of 1) it suffices to store the current position on the top of the stack
+// once. Matching now becomes merely incrementing the current position and
+// backtracking becomes decrementing the current position and checking the
+// result against the stored current position. This is faster and saves
+// space.
+// * The current state is virtualized.
+// This is used to defer expensive operations until it is clear that they
+// are needed and to generate code for a node more than once, allowing
+// specialized an efficient versions of the code to be created. This is
+// explained in the section below.
+//
+// Execution state virtualization.
+//
+// Instead of emitting code, nodes that manipulate the state can record their
+// manipulation in an object called the Trace. The Trace object can record a
+// current position offset, an optional backtrack code location on the top of
+// the virtualized backtrack stack and some register changes. When a node is
+// to be emitted it can flush the Trace or update it. Flushing the Trace
+// will emit code to bring the actual state into line with the virtual state.
+// Avoiding flushing the state can postpone some work (e.g. updates of capture
+// registers). Postponing work can save time when executing the regular
+// expression since it may be found that the work never has to be done as a
+// failure to match can occur. In addition it is much faster to jump to a
+// known backtrack code location than it is to pop an unknown backtrack
+// location from the stack and jump there.
+//
+// The virtual state found in the Trace affects code generation. For example
+// the virtual state contains the difference between the actual current
+// position and the virtual current position, and matching code needs to use
+// this offset to attempt a match in the correct location of the input
+// string. Therefore code generated for a non-trivial trace is specialized
+// to that trace. The code generator therefore has the ability to generate
+// code for each node several times. In order to limit the size of the
+// generated code there is an arbitrary limit on how many specialized sets of
+// code may be generated for a given node. If the limit is reached, the
+// trace is flushed and a generic version of the code for a node is emitted.
+// This is subsequently used for that node. The code emitted for non-generic
+// trace is not recorded in the node and so it cannot currently be reused in
+// the event that code generation is requested for an identical trace.
+
+/* static */ TextElement
+TextElement::Atom(RegExpAtom* atom)
+{
+ return TextElement(ATOM, atom);
+}
+
+/* static */ TextElement
+TextElement::CharClass(RegExpCharacterClass* char_class)
+{
+ return TextElement(CHAR_CLASS, char_class);
+}
+
+int
+TextElement::length() const
+{
+ switch (text_type()) {
+ case ATOM:
+ return atom()->length();
+ case CHAR_CLASS:
+ return 1;
+ }
+ MOZ_CRASH("Bad text type");
+}
+
+class FrequencyCollator
+{
+ public:
+ FrequencyCollator() : total_samples_(0) {
+ for (int i = 0; i < RegExpMacroAssembler::kTableSize; i++) {
+ frequencies_[i] = CharacterFrequency(i);
+ }
+ }
+
+ void CountCharacter(int character) {
+ int index = (character & RegExpMacroAssembler::kTableMask);
+ frequencies_[index].Increment();
+ total_samples_++;
+ }
+
+ // Does not measure in percent, but rather per-128 (the table size from the
+ // regexp macro assembler).
+ int Frequency(int in_character) {
+ MOZ_ASSERT((in_character & RegExpMacroAssembler::kTableMask) == in_character);
+ if (total_samples_ < 1) return 1; // Division by zero.
+ int freq_in_per128 =
+ (frequencies_[in_character].counter() * 128) / total_samples_;
+ return freq_in_per128;
+ }
+
+ private:
+ class CharacterFrequency {
+ public:
+ CharacterFrequency() : counter_(0), character_(-1) { }
+ explicit CharacterFrequency(int character)
+ : counter_(0), character_(character)
+ {}
+
+ void Increment() { counter_++; }
+ int counter() { return counter_; }
+ int character() { return character_; }
+
+ private:
+ int counter_;
+ int character_;
+ };
+
+ private:
+ CharacterFrequency frequencies_[RegExpMacroAssembler::kTableSize];
+ int total_samples_;
+};
+
+class irregexp::RegExpCompiler
+{
+ public:
+ RegExpCompiler(JSContext* cx, LifoAlloc* alloc, int capture_count,
+ bool ignore_case, bool is_ascii, bool match_only, bool unicode);
+
+ int AllocateRegister() {
+ if (next_register_ >= RegExpMacroAssembler::kMaxRegister) {
+ reg_exp_too_big_ = true;
+ return next_register_;
+ }
+ return next_register_++;
+ }
+
+ RegExpCode Assemble(JSContext* cx,
+ RegExpMacroAssembler* assembler,
+ RegExpNode* start,
+ int capture_count);
+
+ inline void AddWork(RegExpNode* node) {
+ AutoEnterOOMUnsafeRegion oomUnsafe;
+ if (!work_list_.append(node))
+ oomUnsafe.crash("AddWork");
+ }
+
+ static const int kImplementationOffset = 0;
+ static const int kNumberOfRegistersOffset = 0;
+ static const int kCodeOffset = 1;
+
+ RegExpMacroAssembler* macro_assembler() { return macro_assembler_; }
+ EndNode* accept() { return accept_; }
+
+ static const int kMaxRecursion = 100;
+ inline int recursion_depth() { return recursion_depth_; }
+ inline void IncrementRecursionDepth() { recursion_depth_++; }
+ inline void DecrementRecursionDepth() { recursion_depth_--; }
+
+ void SetRegExpTooBig() { reg_exp_too_big_ = true; }
+
+ inline bool ignore_case() { return ignore_case_; }
+ inline bool ascii() { return ascii_; }
+ inline bool unicode() { return unicode_; }
+ FrequencyCollator* frequency_collator() { return &frequency_collator_; }
+
+ int current_expansion_factor() { return current_expansion_factor_; }
+ void set_current_expansion_factor(int value) {
+ current_expansion_factor_ = value;
+ }
+
+ JSContext* cx() const { return cx_; }
+ LifoAlloc* alloc() const { return alloc_; }
+
+ static const int kNoRegister = -1;
+
+ private:
+ EndNode* accept_;
+ int next_register_;
+ Vector<RegExpNode*, 4, SystemAllocPolicy> work_list_;
+ int recursion_depth_;
+ RegExpMacroAssembler* macro_assembler_;
+ bool ignore_case_;
+ bool ascii_;
+ bool match_only_;
+ bool unicode_;
+ bool reg_exp_too_big_;
+ int current_expansion_factor_;
+ FrequencyCollator frequency_collator_;
+ JSContext* cx_;
+ LifoAlloc* alloc_;
+};
+
+class RecursionCheck
+{
+ public:
+ explicit RecursionCheck(RegExpCompiler* compiler) : compiler_(compiler) {
+ compiler->IncrementRecursionDepth();
+ }
+ ~RecursionCheck() { compiler_->DecrementRecursionDepth(); }
+
+ private:
+ RegExpCompiler* compiler_;
+};
+
+// Attempts to compile the regexp using an Irregexp code generator. Returns
+// a fixed array or a null handle depending on whether it succeeded.
+RegExpCompiler::RegExpCompiler(JSContext* cx, LifoAlloc* alloc, int capture_count,
+ bool ignore_case, bool ascii, bool match_only, bool unicode)
+ : next_register_(2 * (capture_count + 1)),
+ recursion_depth_(0),
+ ignore_case_(ignore_case),
+ ascii_(ascii),
+ match_only_(match_only),
+ unicode_(unicode),
+ reg_exp_too_big_(false),
+ current_expansion_factor_(1),
+ frequency_collator_(),
+ cx_(cx),
+ alloc_(alloc)
+{
+ accept_ = alloc->newInfallible<EndNode>(alloc, EndNode::ACCEPT);
+ MOZ_ASSERT(next_register_ - 1 <= RegExpMacroAssembler::kMaxRegister);
+}
+
+RegExpCode
+RegExpCompiler::Assemble(JSContext* cx,
+ RegExpMacroAssembler* assembler,
+ RegExpNode* start,
+ int capture_count)
+{
+ macro_assembler_ = assembler;
+ macro_assembler_->set_slow_safe(false);
+
+ // The LifoAlloc used by the regexp compiler is infallible and is currently
+ // expected to crash on OOM. Thus we have to disable the assertions made to
+ // prevent us from allocating any new chunk in the LifoAlloc. This is needed
+ // because the jit::MacroAssembler turns these assertions on by default.
+ LifoAlloc::AutoFallibleScope fallibleAllocator(alloc());
+
+ jit::Label fail;
+ macro_assembler_->PushBacktrack(&fail);
+ Trace new_trace;
+ start->Emit(this, &new_trace);
+ macro_assembler_->BindBacktrack(&fail);
+ macro_assembler_->Fail();
+
+ while (!work_list_.empty())
+ work_list_.popCopy()->Emit(this, &new_trace);
+
+ RegExpCode code = macro_assembler_->GenerateCode(cx, match_only_);
+ if (code.empty())
+ return RegExpCode();
+
+ if (reg_exp_too_big_) {
+ code.destroy();
+ JS_ReportErrorASCII(cx, "regexp too big");
+ return RegExpCode();
+ }
+
+ return code;
+}
+
+template <typename CharT>
+static void
+SampleChars(FrequencyCollator* collator, const CharT* chars, size_t length)
+{
+ // Sample some characters from the middle of the string.
+ static const int kSampleSize = 128;
+
+ int chars_sampled = 0;
+ int half_way = (int(length) - kSampleSize) / 2;
+ for (size_t i = Max(0, half_way);
+ i < length && chars_sampled < kSampleSize;
+ i++, chars_sampled++)
+ {
+ collator->CountCharacter(chars[i]);
+ }
+}
+
+static bool
+IsNativeRegExpEnabled(JSContext* cx)
+{
+#ifdef JS_CODEGEN_NONE
+ return false;
+#else
+ return cx->options().nativeRegExp();
+#endif
+}
+
+RegExpCode
+irregexp::CompilePattern(JSContext* cx, RegExpShared* shared, RegExpCompileData* data,
+ HandleLinearString sample, bool is_global, bool ignore_case,
+ bool is_ascii, bool match_only, bool force_bytecode, bool sticky,
+ bool unicode)
+{
+ if ((data->capture_count + 1) * 2 - 1 > RegExpMacroAssembler::kMaxRegister) {
+ JS_ReportErrorASCII(cx, "regexp too big");
+ return RegExpCode();
+ }
+
+ LifoAlloc& alloc = cx->tempLifoAlloc();
+ RegExpCompiler compiler(cx, &alloc, data->capture_count, ignore_case, is_ascii, match_only,
+ unicode);
+
+ // Sample some characters from the middle of the string.
+ if (sample->hasLatin1Chars()) {
+ JS::AutoCheckCannotGC nogc;
+ SampleChars(compiler.frequency_collator(), sample->latin1Chars(nogc), sample->length());
+ } else {
+ JS::AutoCheckCannotGC nogc;
+ SampleChars(compiler.frequency_collator(), sample->twoByteChars(nogc), sample->length());
+ }
+
+ // Wrap the body of the regexp in capture #0.
+ RegExpNode* captured_body = RegExpCapture::ToNode(data->tree,
+ 0,
+ &compiler,
+ compiler.accept());
+ RegExpNode* node = captured_body;
+ bool is_end_anchored = data->tree->IsAnchoredAtEnd();
+ bool is_start_anchored = sticky || data->tree->IsAnchoredAtStart();
+ int max_length = data->tree->max_match();
+ if (!is_start_anchored) {
+ // Add a .*? at the beginning, outside the body capture, unless
+ // this expression is anchored at the beginning.
+ RegExpNode* loop_node =
+ RegExpQuantifier::ToNode(0,
+ RegExpTree::kInfinity,
+ false,
+ alloc.newInfallible<RegExpCharacterClass>('*'),
+ &compiler,
+ captured_body,
+ data->contains_anchor);
+
+ if (data->contains_anchor) {
+ // Unroll loop once, to take care of the case that might start
+ // at the start of input.
+ ChoiceNode* first_step_node = alloc.newInfallible<ChoiceNode>(&alloc, 2);
+ RegExpNode* char_class =
+ alloc.newInfallible<TextNode>(alloc.newInfallible<RegExpCharacterClass>('*'), loop_node);
+ first_step_node->AddAlternative(GuardedAlternative(captured_body));
+ first_step_node->AddAlternative(GuardedAlternative(char_class));
+ node = first_step_node;
+ } else {
+ node = loop_node;
+ }
+ }
+ if (is_ascii) {
+ node = node->FilterASCII(RegExpCompiler::kMaxRecursion, ignore_case, unicode);
+ // Do it again to propagate the new nodes to places where they were not
+ // put because they had not been calculated yet.
+ if (node != nullptr) {
+ node = node->FilterASCII(RegExpCompiler::kMaxRecursion, ignore_case, unicode);
+ }
+ }
+
+ if (node == nullptr)
+ node = alloc.newInfallible<EndNode>(&alloc, EndNode::BACKTRACK);
+
+ Analysis analysis(cx, ignore_case, is_ascii, unicode);
+ analysis.EnsureAnalyzed(node);
+ if (analysis.has_failed()) {
+ JS_ReportErrorASCII(cx, "%s", analysis.errorMessage());
+ return RegExpCode();
+ }
+
+ Maybe<jit::JitContext> ctx;
+ Maybe<NativeRegExpMacroAssembler> native_assembler;
+ Maybe<InterpretedRegExpMacroAssembler> interpreted_assembler;
+
+ RegExpMacroAssembler* assembler;
+ if (IsNativeRegExpEnabled(cx) &&
+ !force_bytecode &&
+ jit::CanLikelyAllocateMoreExecutableMemory() &&
+ shared->getSource()->length() < 32 * 1024)
+ {
+ NativeRegExpMacroAssembler::Mode mode =
+ is_ascii ? NativeRegExpMacroAssembler::ASCII
+ : NativeRegExpMacroAssembler::CHAR16;
+
+ ctx.emplace(cx, (jit::TempAllocator*) nullptr);
+ native_assembler.emplace(&alloc, shared, cx->runtime(), mode, (data->capture_count + 1) * 2);
+ assembler = native_assembler.ptr();
+ } else {
+ interpreted_assembler.emplace(&alloc, shared, (data->capture_count + 1) * 2);
+ assembler = interpreted_assembler.ptr();
+ }
+
+ // Inserted here, instead of in Assembler, because it depends on information
+ // in the AST that isn't replicated in the Node structure.
+ static const int kMaxBacksearchLimit = 1024;
+ if (is_end_anchored &&
+ !is_start_anchored &&
+ max_length < kMaxBacksearchLimit) {
+ assembler->SetCurrentPositionFromEnd(max_length);
+ }
+
+ if (is_global) {
+ assembler->set_global_mode((data->tree->min_match() > 0)
+ ? RegExpMacroAssembler::GLOBAL_NO_ZERO_LENGTH_CHECK
+ : RegExpMacroAssembler::GLOBAL);
+ }
+
+ return compiler.Assemble(cx, assembler, node, data->capture_count);
+}
+
+template <typename CharT>
+RegExpRunStatus
+irregexp::ExecuteCode(JSContext* cx, jit::JitCode* codeBlock, const CharT* chars, size_t start,
+ size_t length, MatchPairs* matches, size_t* endIndex)
+{
+ typedef void (*RegExpCodeSignature)(InputOutputData*);
+
+ InputOutputData data(chars, chars + length, start, matches, endIndex);
+
+ RegExpCodeSignature function = reinterpret_cast<RegExpCodeSignature>(codeBlock->raw());
+
+ {
+ JS::AutoSuppressGCAnalysis nogc;
+ CALL_GENERATED_1(function, &data);
+ }
+
+ return (RegExpRunStatus) data.result;
+}
+
+template RegExpRunStatus
+irregexp::ExecuteCode(JSContext* cx, jit::JitCode* codeBlock, const Latin1Char* chars, size_t start,
+ size_t length, MatchPairs* matches, size_t* endIndex);
+
+template RegExpRunStatus
+irregexp::ExecuteCode(JSContext* cx, jit::JitCode* codeBlock, const char16_t* chars, size_t start,
+ size_t length, MatchPairs* matches, size_t* endIndex);
+
+// -------------------------------------------------------------------
+// Tree to graph conversion
+
+RegExpNode*
+RegExpAtom::ToNode(RegExpCompiler* compiler, RegExpNode* on_success)
+{
+ TextElementVector* elms =
+ compiler->alloc()->newInfallible<TextElementVector>(*compiler->alloc());
+ elms->append(TextElement::Atom(this));
+ return compiler->alloc()->newInfallible<TextNode>(elms, on_success);
+}
+
+RegExpNode*
+RegExpText::ToNode(RegExpCompiler* compiler, RegExpNode* on_success)
+{
+ return compiler->alloc()->newInfallible<TextNode>(&elements_, on_success);
+}
+
+RegExpNode*
+RegExpCharacterClass::ToNode(RegExpCompiler* compiler, RegExpNode* on_success)
+{
+ return compiler->alloc()->newInfallible<TextNode>(this, on_success);
+}
+
+RegExpNode*
+RegExpDisjunction::ToNode(RegExpCompiler* compiler, RegExpNode* on_success)
+{
+ const RegExpTreeVector& alternatives = this->alternatives();
+ size_t length = alternatives.length();
+ ChoiceNode* result = compiler->alloc()->newInfallible<ChoiceNode>(compiler->alloc(), length);
+ for (size_t i = 0; i < length; i++) {
+ GuardedAlternative alternative(alternatives[i]->ToNode(compiler, on_success));
+ result->AddAlternative(alternative);
+ }
+ return result;
+}
+
+RegExpNode*
+RegExpQuantifier::ToNode(RegExpCompiler* compiler, RegExpNode* on_success)
+{
+ return ToNode(min(),
+ max(),
+ is_greedy(),
+ body(),
+ compiler,
+ on_success);
+}
+
+// Scoped object to keep track of how much we unroll quantifier loops in the
+// regexp graph generator.
+class RegExpExpansionLimiter
+{
+ public:
+ static const int kMaxExpansionFactor = 6;
+ RegExpExpansionLimiter(RegExpCompiler* compiler, int factor)
+ : compiler_(compiler),
+ saved_expansion_factor_(compiler->current_expansion_factor()),
+ ok_to_expand_(saved_expansion_factor_ <= kMaxExpansionFactor)
+ {
+ MOZ_ASSERT(factor > 0);
+ 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);
+ }
+ }
+ }
+
+ ~RegExpExpansionLimiter() {
+ compiler_->set_current_expansion_factor(saved_expansion_factor_);
+ }
+
+ bool ok_to_expand() { return ok_to_expand_; }
+
+ private:
+ RegExpCompiler* compiler_;
+ int saved_expansion_factor_;
+ bool ok_to_expand_;
+};
+
+/* static */ RegExpNode*
+RegExpQuantifier::ToNode(int min,
+ int max,
+ bool is_greedy,
+ RegExpTree* body,
+ RegExpCompiler* compiler,
+ RegExpNode* on_success,
+ bool not_at_start /* = false */)
+{
+ // 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 = RegExpCompiler::kNoRegister;
+ Interval capture_registers = body->CaptureRegisters();
+ bool needs_capture_clearing = !capture_registers.is_empty();
+ LifoAlloc* alloc = compiler->alloc();
+
+ if (body_can_be_empty) {
+ body_start_reg = compiler->AllocateRegister();
+ } else if (!needs_capture_clearing) {
+ // Only unroll if there are no captures and the body can't be
+ // empty.
+ {
+ RegExpExpansionLimiter limiter(compiler, min + ((max != min) ? 1 : 0));
+ if (min > 0 && min <= kMaxUnrolledMinMatches && limiter.ok_to_expand()) {
+ int new_max = (max == kInfinity) ? max : max - min;
+ // Recurse once to get the loop or optional matches after the fixed
+ // ones.
+ RegExpNode* 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.
+ for (int i = 0; i < min; i++)
+ answer = body->ToNode(compiler, answer);
+ return answer;
+ }
+ }
+ if (max <= kMaxUnrolledMaxMatches && min == 0) {
+ MOZ_ASSERT(max > 0); // Due to the 'if' above.
+ RegExpExpansionLimiter limiter(compiler, max);
+ if (limiter.ok_to_expand()) {
+ // Unroll the optional matches up to max.
+ RegExpNode* answer = on_success;
+ for (int i = 0; i < max; i++) {
+ ChoiceNode* alternation = alloc->newInfallible<ChoiceNode>(alloc, 2);
+ 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) alternation->set_not_at_start();
+ }
+ return answer;
+ }
+ }
+ }
+ bool has_min = min > 0;
+ bool has_max = max < RegExpTree::kInfinity;
+ bool needs_counter = has_min || has_max;
+ int reg_ctr = needs_counter
+ ? compiler->AllocateRegister()
+ : RegExpCompiler::kNoRegister;
+ LoopChoiceNode* center = alloc->newInfallible<LoopChoiceNode>(alloc, body->min_match() == 0);
+ if (not_at_start)
+ center->set_not_at_start();
+ RegExpNode* loop_return = needs_counter
+ ? static_cast<RegExpNode*>(ActionNode::IncrementRegister(reg_ctr, center))
+ : static_cast<RegExpNode*>(center);
+ 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);
+ }
+ RegExpNode* body_node = body->ToNode(compiler, loop_return);
+ 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::StorePosition(body_start_reg, false, 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);
+ }
+ GuardedAlternative body_alt(body_node);
+ if (has_max) {
+ Guard* body_guard = alloc->newInfallible<Guard>(reg_ctr, Guard::LT, max);
+ body_alt.AddGuard(alloc, body_guard);
+ }
+ GuardedAlternative rest_alt(on_success);
+ if (has_min) {
+ Guard* rest_guard = alloc->newInfallible<Guard>(reg_ctr, Guard::GEQ, min);
+ rest_alt.AddGuard(alloc, rest_guard);
+ }
+ if (is_greedy) {
+ center->AddLoopAlternative(body_alt);
+ center->AddContinueAlternative(rest_alt);
+ } else {
+ center->AddContinueAlternative(rest_alt);
+ center->AddLoopAlternative(body_alt);
+ }
+ if (needs_counter)
+ return ActionNode::SetRegister(reg_ctr, 0, center);
+ return center;
+}
+
+RegExpNode*
+RegExpAssertion::ToNode(RegExpCompiler* compiler,
+ RegExpNode* on_success)
+{
+ NodeInfo info;
+ LifoAlloc* alloc = compiler->alloc();
+
+ switch (assertion_type()) {
+ case START_OF_LINE:
+ return AssertionNode::AfterNewline(on_success);
+ case START_OF_INPUT:
+ return AssertionNode::AtStart(on_success);
+ case BOUNDARY:
+ return AssertionNode::AtBoundary(on_success);
+ case NON_BOUNDARY:
+ return AssertionNode::AtNonBoundary(on_success);
+ case END_OF_INPUT:
+ return AssertionNode::AtEnd(on_success);
+ case 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 = alloc->newInfallible<ChoiceNode>(alloc, 2);
+ // Create a newline atom.
+ CharacterRangeVector* newline_ranges = alloc->newInfallible<CharacterRangeVector>(*alloc);
+ CharacterRange::AddClassEscape(alloc, 'n', newline_ranges);
+ RegExpCharacterClass* newline_atom = alloc->newInfallible<RegExpCharacterClass>('n');
+ TextNode* newline_matcher =
+ alloc->newInfallible<TextNode>(newline_atom,
+ ActionNode::PositiveSubmatchSuccess(stack_pointer_register,
+ position_register,
+ 0, // No captures inside.
+ -1, // Ignored if no captures.
+ on_success));
+ // Create an end-of-input matcher.
+ RegExpNode* end_of_line =
+ ActionNode::BeginSubmatch(stack_pointer_register, position_register, newline_matcher);
+
+ // 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);
+ return result;
+ }
+ case NOT_AFTER_LEAD_SURROGATE:
+ return AssertionNode::NotAfterLeadSurrogate(on_success);
+ case NOT_IN_SURROGATE_PAIR:
+ return AssertionNode::NotInSurrogatePair(on_success);
+ default:
+ MOZ_CRASH("Bad assertion type");
+ }
+ return on_success;
+}
+
+RegExpNode*
+RegExpBackReference::ToNode(RegExpCompiler* compiler, RegExpNode* on_success)
+{
+ return compiler->alloc()->newInfallible<BackReferenceNode>(RegExpCapture::StartRegister(index()),
+ RegExpCapture::EndRegister(index()),
+ on_success);
+}
+
+RegExpNode*
+RegExpEmpty::ToNode(RegExpCompiler* compiler, RegExpNode* on_success)
+{
+ return on_success;
+}
+
+RegExpNode*
+RegExpLookahead::ToNode(RegExpCompiler* compiler, RegExpNode* 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;
+
+ if (is_positive()) {
+ RegExpNode* bodyNode =
+ body()->ToNode(compiler,
+ ActionNode::PositiveSubmatchSuccess(stack_pointer_register,
+ position_register,
+ register_count,
+ register_start,
+ on_success));
+ return ActionNode::BeginSubmatch(stack_pointer_register,
+ position_register,
+ bodyNode);
+ }
+
+ // We use a ChoiceNode for a negative lookahead because it has most of
+ // the characteristics we need. It has the body of the lookahead as its
+ // first alternative and the expression after the lookahead of the second
+ // alternative. If the first alternative succeeds then the
+ // NegativeSubmatchSuccess will unwind the stack including everything the
+ // choice node set up and backtrack. If the first alternative fails then
+ // the second alternative is tried, which is exactly the desired result
+ // for a negative lookahead. The NegativeLookaheadChoiceNode is a special
+ // ChoiceNode that knows to ignore the first exit when calculating quick
+ // checks.
+ LifoAlloc* alloc = compiler->alloc();
+
+ RegExpNode* success =
+ alloc->newInfallible<NegativeSubmatchSuccess>(alloc,
+ stack_pointer_register,
+ position_register,
+ register_count,
+ register_start);
+ GuardedAlternative body_alt(body()->ToNode(compiler, success));
+
+ ChoiceNode* choice_node =
+ alloc->newInfallible<NegativeLookaheadChoiceNode>(alloc, body_alt, GuardedAlternative(on_success));
+
+ return ActionNode::BeginSubmatch(stack_pointer_register,
+ position_register,
+ choice_node);
+}
+
+RegExpNode*
+RegExpCapture::ToNode(RegExpCompiler* compiler, RegExpNode* on_success)
+{
+ return ToNode(body(), index(), compiler, on_success);
+}
+
+/* static */ RegExpNode*
+RegExpCapture::ToNode(RegExpTree* body,
+ int index,
+ RegExpCompiler* compiler,
+ RegExpNode* on_success)
+{
+ int start_reg = RegExpCapture::StartRegister(index);
+ int end_reg = RegExpCapture::EndRegister(index);
+ RegExpNode* store_end = ActionNode::StorePosition(end_reg, true, on_success);
+ RegExpNode* body_node = body->ToNode(compiler, store_end);
+ return ActionNode::StorePosition(start_reg, true, body_node);
+}
+
+RegExpNode*
+RegExpAlternative::ToNode(RegExpCompiler* compiler, RegExpNode* on_success)
+{
+ const RegExpTreeVector& children = nodes();
+ RegExpNode* current = on_success;
+ for (int i = children.length() - 1; i >= 0; i--)
+ current = children[i]->ToNode(compiler, current);
+ return current;
+}
+
+// -------------------------------------------------------------------
+// BoyerMooreLookahead
+
+ContainedInLattice
+irregexp::AddRange(ContainedInLattice containment,
+ const int* ranges,
+ int ranges_length,
+ Interval new_range)
+{
+ MOZ_ASSERT((ranges_length & 1) == 1);
+ MOZ_ASSERT(ranges[ranges_length - 1] == kMaxUtf16CodeUnit + 1);
+ if (containment == kLatticeUnknown) return containment;
+ bool inside = false;
+ int last = 0;
+ for (int i = 0; i < ranges_length; inside = !inside, last = ranges[i], i++) {
+ // Consider the range from last to ranges[i].
+ // We haven't got to the new range yet.
+ if (ranges[i] <= new_range.from())
+ continue;
+
+ // New range is wholly inside last-ranges[i]. Note that new_range.to() is
+ // inclusive, but the values in ranges are not.
+ if (last <= new_range.from() && new_range.to() < ranges[i])
+ return Combine(containment, inside ? kLatticeIn : kLatticeOut);
+
+ return kLatticeUnknown;
+ }
+ return containment;
+}
+
+void
+BoyerMoorePositionInfo::Set(int character)
+{
+ SetInterval(Interval(character, character));
+}
+
+void
+BoyerMoorePositionInfo::SetInterval(const Interval& interval)
+{
+ s_ = AddRange(s_, kSpaceRanges, kSpaceRangeCount, interval);
+ w_ = AddRange(w_, kWordRanges, kWordRangeCount, interval);
+ d_ = AddRange(d_, kDigitRanges, kDigitRangeCount, interval);
+ surrogate_ =
+ AddRange(surrogate_, kSurrogateRanges, kSurrogateRangeCount, interval);
+ if (interval.to() - interval.from() >= kMapSize - 1) {
+ if (map_count_ != kMapSize) {
+ map_count_ = kMapSize;
+ for (int i = 0; i < kMapSize; i++)
+ map_[i] = true;
+ }
+ return;
+ }
+ for (int i = interval.from(); i <= interval.to(); i++) {
+ int mod_character = (i & kMask);
+ if (!map_[mod_character]) {
+ map_count_++;
+ map_[mod_character] = true;
+ }
+ if (map_count_ == kMapSize)
+ return;
+ }
+}
+
+void
+BoyerMoorePositionInfo::SetAll()
+{
+ s_ = w_ = d_ = kLatticeUnknown;
+ if (map_count_ != kMapSize) {
+ map_count_ = kMapSize;
+ for (int i = 0; i < kMapSize; i++)
+ map_[i] = true;
+ }
+}
+
+BoyerMooreLookahead::BoyerMooreLookahead(LifoAlloc* alloc, size_t length, RegExpCompiler* compiler)
+ : length_(length), compiler_(compiler), bitmaps_(*alloc)
+{
+ max_char_ = MaximumCharacter(compiler->ascii());
+
+ bitmaps_.reserve(length);
+ for (size_t i = 0; i < length; i++)
+ bitmaps_.append(alloc->newInfallible<BoyerMoorePositionInfo>(alloc));
+}
+
+// Find the longest range of lookahead that has the fewest number of different
+// characters that can occur at a given position. Since we are optimizing two
+// different parameters at once this is a tradeoff.
+bool BoyerMooreLookahead::FindWorthwhileInterval(int* from, int* to) {
+ int biggest_points = 0;
+ // If more than 32 characters out of 128 can occur it is unlikely that we can
+ // be lucky enough to step forwards much of the time.
+ const int kMaxMax = 32;
+ for (int max_number_of_chars = 4;
+ max_number_of_chars < kMaxMax;
+ max_number_of_chars *= 2) {
+ biggest_points =
+ FindBestInterval(max_number_of_chars, biggest_points, from, to);
+ }
+ if (biggest_points == 0) return false;
+ return true;
+}
+
+// Find the highest-points range between 0 and length_ where the character
+// information is not too vague. 'Too vague' means that there are more than
+// max_number_of_chars that can occur at this position. Calculates the number
+// of points as the product of width-of-the-range and
+// probability-of-finding-one-of-the-characters, where the probability is
+// calculated using the frequency distribution of the sample subject string.
+int
+BoyerMooreLookahead::FindBestInterval(int max_number_of_chars, int old_biggest_points,
+ int* from, int* to)
+{
+ int biggest_points = old_biggest_points;
+ static const int kSize = RegExpMacroAssembler::kTableSize;
+ for (int i = 0; i < length_; ) {
+ while (i < length_ && Count(i) > max_number_of_chars) i++;
+ if (i == length_) break;
+ int remembered_from = i;
+ bool union_map[kSize];
+ for (int j = 0; j < kSize; j++) union_map[j] = false;
+ while (i < length_ && Count(i) <= max_number_of_chars) {
+ BoyerMoorePositionInfo* map = bitmaps_[i];
+ for (int j = 0; j < kSize; j++) union_map[j] |= map->at(j);
+ i++;
+ }
+ int frequency = 0;
+ for (int j = 0; j < kSize; j++) {
+ if (union_map[j]) {
+ // Add 1 to the frequency to give a small per-character boost for
+ // the cases where our sampling is not good enough and many
+ // characters have a frequency of zero. This means the frequency
+ // can theoretically be up to 2*kSize though we treat it mostly as
+ // a fraction of kSize.
+ frequency += compiler_->frequency_collator()->Frequency(j) + 1;
+ }
+ }
+ // We use the probability of skipping times the distance we are skipping to
+ // judge the effectiveness of this. Actually we have a cut-off: By
+ // dividing by 2 we switch off the skipping if the probability of skipping
+ // is less than 50%. This is because the multibyte mask-and-compare
+ // skipping in quickcheck is more likely to do well on this case.
+ bool in_quickcheck_range = ((i - remembered_from < 4) ||
+ (compiler_->ascii() ? remembered_from <= 4 : remembered_from <= 2));
+ // Called 'probability' but it is only a rough estimate and can actually
+ // be outside the 0-kSize range.
+ int probability = (in_quickcheck_range ? kSize / 2 : kSize) - frequency;
+ int points = (i - remembered_from) * probability;
+ if (points > biggest_points) {
+ *from = remembered_from;
+ *to = i - 1;
+ biggest_points = points;
+ }
+ }
+ return biggest_points;
+}
+
+// Take all the characters that will not prevent a successful match if they
+// occur in the subject string in the range between min_lookahead and
+// max_lookahead (inclusive) measured from the current position. If the
+// character at max_lookahead offset is not one of these characters, then we
+// can safely skip forwards by the number of characters in the range.
+int BoyerMooreLookahead::GetSkipTable(int min_lookahead,
+ int max_lookahead,
+ uint8_t* boolean_skip_table)
+{
+ const int kSize = RegExpMacroAssembler::kTableSize;
+
+ const int kSkipArrayEntry = 0;
+ const int kDontSkipArrayEntry = 1;
+
+ for (int i = 0; i < kSize; i++)
+ boolean_skip_table[i] = kSkipArrayEntry;
+ int skip = max_lookahead + 1 - min_lookahead;
+
+ for (int i = max_lookahead; i >= min_lookahead; i--) {
+ BoyerMoorePositionInfo* map = bitmaps_[i];
+ for (int j = 0; j < kSize; j++) {
+ if (map->at(j))
+ boolean_skip_table[j] = kDontSkipArrayEntry;
+ }
+ }
+
+ return skip;
+}
+
+// See comment on the implementation of GetSkipTable.
+bool
+BoyerMooreLookahead::EmitSkipInstructions(RegExpMacroAssembler* masm)
+{
+ const int kSize = RegExpMacroAssembler::kTableSize;
+
+ int min_lookahead = 0;
+ int max_lookahead = 0;
+
+ if (!FindWorthwhileInterval(&min_lookahead, &max_lookahead))
+ return false;
+
+ bool found_single_character = false;
+ int single_character = 0;
+ for (int i = max_lookahead; i >= min_lookahead; i--) {
+ BoyerMoorePositionInfo* map = bitmaps_[i];
+ if (map->map_count() > 1 ||
+ (found_single_character && map->map_count() != 0)) {
+ found_single_character = false;
+ break;
+ }
+ for (int j = 0; j < kSize; j++) {
+ if (map->at(j)) {
+ found_single_character = true;
+ single_character = j;
+ break;
+ }
+ }
+ }
+
+ int lookahead_width = max_lookahead + 1 - min_lookahead;
+
+ if (found_single_character && lookahead_width == 1 && max_lookahead < 3) {
+ // The mask-compare can probably handle this better.
+ return false;
+ }
+
+ if (found_single_character) {
+ jit::Label cont, again;
+ masm->Bind(&again);
+ masm->LoadCurrentCharacter(max_lookahead, &cont, true);
+ if (max_char_ > kSize) {
+ masm->CheckCharacterAfterAnd(single_character,
+ RegExpMacroAssembler::kTableMask,
+ &cont);
+ } else {
+ masm->CheckCharacter(single_character, &cont);
+ }
+ masm->AdvanceCurrentPosition(lookahead_width);
+ masm->JumpOrBacktrack(&again);
+ masm->Bind(&cont);
+ return true;
+ }
+
+ uint8_t* boolean_skip_table;
+ {
+ AutoEnterOOMUnsafeRegion oomUnsafe;
+ boolean_skip_table = static_cast<uint8_t*>(js_malloc(kSize));
+ if (!boolean_skip_table || !masm->shared->addTable(boolean_skip_table))
+ oomUnsafe.crash("Table malloc");
+ }
+
+ int skip_distance = GetSkipTable(min_lookahead, max_lookahead, boolean_skip_table);
+ MOZ_ASSERT(skip_distance != 0);
+
+ jit::Label cont, again;
+ masm->Bind(&again);
+ masm->LoadCurrentCharacter(max_lookahead, &cont, true);
+ masm->CheckBitInTable(boolean_skip_table, &cont);
+ masm->AdvanceCurrentPosition(skip_distance);
+ masm->JumpOrBacktrack(&again);
+ masm->Bind(&cont);
+
+ return true;
+}
+
+bool
+BoyerMooreLookahead::CheckOverRecursed()
+{
+ JS_CHECK_RECURSION(compiler()->cx(), compiler()->SetRegExpTooBig(); return false);
+ return true;
+}
+
+// -------------------------------------------------------------------
+// Trace
+
+bool Trace::DeferredAction::Mentions(int that)
+{
+ if (action_type() == ActionNode::CLEAR_CAPTURES) {
+ Interval range = static_cast<DeferredClearCaptures*>(this)->range();
+ return range.Contains(that);
+ }
+ return reg() == that;
+}
+
+bool Trace::mentions_reg(int reg)
+{
+ for (DeferredAction* action = actions_; action != nullptr; action = action->next()) {
+ if (action->Mentions(reg))
+ return true;
+ }
+ return false;
+}
+
+bool
+Trace::GetStoredPosition(int reg, int* cp_offset)
+{
+ MOZ_ASSERT(0 == *cp_offset);
+ for (DeferredAction* action = actions_; action != nullptr; action = action->next()) {
+ if (action->Mentions(reg)) {
+ if (action->action_type() == ActionNode::STORE_POSITION) {
+ *cp_offset = static_cast<DeferredCapture*>(action)->cp_offset();
+ return true;
+ }
+ return false;
+ }
+ }
+ return false;
+}
+
+int
+Trace::FindAffectedRegisters(LifoAlloc* alloc, OutSet* affected_registers)
+{
+ int max_register = RegExpCompiler::kNoRegister;
+ for (DeferredAction* action = actions_; action != nullptr; action = action->next()) {
+ if (action->action_type() == ActionNode::CLEAR_CAPTURES) {
+ Interval range = static_cast<DeferredClearCaptures*>(action)->range();
+ for (int i = range.from(); i <= range.to(); i++)
+ affected_registers->Set(alloc, i);
+ if (range.to() > max_register) max_register = range.to();
+ } else {
+ affected_registers->Set(alloc, action->reg());
+ if (action->reg() > max_register) max_register = action->reg();
+ }
+ }
+ return max_register;
+}
+
+void
+Trace::RestoreAffectedRegisters(RegExpMacroAssembler* assembler,
+ int max_register,
+ OutSet& registers_to_pop,
+ OutSet& registers_to_clear)
+{
+ for (int reg = max_register; reg >= 0; reg--) {
+ if (registers_to_pop.Get(reg)) assembler->PopRegister(reg);
+ else if (registers_to_clear.Get(reg)) {
+ int clear_to = reg;
+ while (reg > 0 && registers_to_clear.Get(reg - 1))
+ reg--;
+ assembler->ClearRegisters(reg, clear_to);
+ }
+ }
+}
+
+enum DeferredActionUndoType {
+ DEFER_IGNORE,
+ DEFER_RESTORE,
+ DEFER_CLEAR
+};
+
+void
+Trace::PerformDeferredActions(LifoAlloc* alloc,
+ RegExpMacroAssembler* assembler,
+ int max_register,
+ OutSet& affected_registers,
+ OutSet* registers_to_pop,
+ OutSet* registers_to_clear)
+{
+ // The "+1" is to avoid a push_limit of zero if stack_limit_slack() is 1.
+ const int push_limit = (assembler->stack_limit_slack() + 1) / 2;
+
+ // Count pushes performed to force a stack limit check occasionally.
+ int pushes = 0;
+
+ for (int reg = 0; reg <= max_register; reg++) {
+ if (!affected_registers.Get(reg))
+ continue;
+
+ // The chronologically first deferred action in the trace
+ // is used to infer the action needed to restore a register
+ // to its previous state (or not, if it's safe to ignore it).
+ DeferredActionUndoType undo_action = DEFER_IGNORE;
+
+ int value = 0;
+ bool absolute = false;
+ bool clear = false;
+ int store_position = -1;
+ // This is a little tricky because we are scanning the actions in reverse
+ // historical order (newest first).
+ for (DeferredAction* action = actions_;
+ action != nullptr;
+ action = action->next()) {
+ if (action->Mentions(reg)) {
+ switch (action->action_type()) {
+ case ActionNode::SET_REGISTER: {
+ Trace::DeferredSetRegister* psr =
+ static_cast<Trace::DeferredSetRegister*>(action);
+ if (!absolute) {
+ value += psr->value();
+ absolute = true;
+ }
+ // SET_REGISTER is currently only used for newly introduced loop
+ // counters. They can have a significant previous value if they
+ // occour in a loop. TODO(lrn): Propagate this information, so
+ // we can set undo_action to IGNORE if we know there is no value to
+ // restore.
+ undo_action = DEFER_RESTORE;
+ MOZ_ASSERT(store_position == -1);
+ MOZ_ASSERT(!clear);
+ break;
+ }
+ case ActionNode::INCREMENT_REGISTER:
+ if (!absolute) {
+ value++;
+ }
+ MOZ_ASSERT(store_position == -1);
+ MOZ_ASSERT(!clear);
+ undo_action = DEFER_RESTORE;
+ break;
+ case ActionNode::STORE_POSITION: {
+ Trace::DeferredCapture* pc =
+ static_cast<Trace::DeferredCapture*>(action);
+ if (!clear && store_position == -1) {
+ store_position = pc->cp_offset();
+ }
+
+ // For captures we know that stores and clears alternate.
+ // Other register, are never cleared, and if the occur
+ // inside a loop, they might be assigned more than once.
+ if (reg <= 1) {
+ // Registers zero and one, aka "capture zero", is
+ // always set correctly if we succeed. There is no
+ // need to undo a setting on backtrack, because we
+ // will set it again or fail.
+ undo_action = DEFER_IGNORE;
+ } else {
+ undo_action = pc->is_capture() ? DEFER_CLEAR : DEFER_RESTORE;
+ }
+ MOZ_ASSERT(!absolute);
+ MOZ_ASSERT(value == 0);
+ break;
+ }
+ case ActionNode::CLEAR_CAPTURES: {
+ // Since we're scanning in reverse order, if we've already
+ // set the position we have to ignore historically earlier
+ // clearing operations.
+ if (store_position == -1) {
+ clear = true;
+ }
+ undo_action = DEFER_RESTORE;
+ MOZ_ASSERT(!absolute);
+ MOZ_ASSERT(value == 0);
+ break;
+ }
+ default:
+ MOZ_CRASH("Bad action");
+ }
+ }
+ }
+ // Prepare for the undo-action (e.g., push if it's going to be popped).
+ if (undo_action == DEFER_RESTORE) {
+ pushes++;
+ RegExpMacroAssembler::StackCheckFlag stack_check =
+ RegExpMacroAssembler::kNoStackLimitCheck;
+ if (pushes == push_limit) {
+ stack_check = RegExpMacroAssembler::kCheckStackLimit;
+ pushes = 0;
+ }
+
+ assembler->PushRegister(reg, stack_check);
+ registers_to_pop->Set(alloc, reg);
+ } else if (undo_action == DEFER_CLEAR) {
+ registers_to_clear->Set(alloc, reg);
+ }
+ // Perform the chronologically last action (or accumulated increment)
+ // for the register.
+ if (store_position != -1) {
+ assembler->WriteCurrentPositionToRegister(reg, store_position);
+ } else if (clear) {
+ assembler->ClearRegisters(reg, reg);
+ } else if (absolute) {
+ assembler->SetRegister(reg, value);
+ } else if (value != 0) {
+ assembler->AdvanceRegister(reg, value);
+ }
+ }
+}
+
+// This is called as we come into a loop choice node and some other tricky
+// nodes. It normalizes the state of the code generator to ensure we can
+// generate generic code.
+void Trace::Flush(RegExpCompiler* compiler, RegExpNode* successor)
+{
+ RegExpMacroAssembler* assembler = compiler->macro_assembler();
+
+ MOZ_ASSERT(!is_trivial());
+
+ if (actions_ == nullptr && backtrack() == nullptr) {
+ // Here we just have some deferred cp advances to fix and we are back to
+ // a normal situation. We may also have to forget some information gained
+ // through a quick check that was already performed.
+ if (cp_offset_ != 0) assembler->AdvanceCurrentPosition(cp_offset_);
+ // Create a new trivial state and generate the node with that.
+ Trace new_state;
+ successor->Emit(compiler, &new_state);
+ return;
+ }
+
+ // Generate deferred actions here along with code to undo them again.
+ OutSet affected_registers;
+
+ if (backtrack() != nullptr) {
+ // Here we have a concrete backtrack location. These are set up by choice
+ // nodes and so they indicate that we have a deferred save of the current
+ // position which we may need to emit here.
+ assembler->PushCurrentPosition();
+ }
+
+ int max_register = FindAffectedRegisters(compiler->alloc(), &affected_registers);
+ OutSet registers_to_pop;
+ OutSet registers_to_clear;
+ PerformDeferredActions(compiler->alloc(),
+ assembler,
+ max_register,
+ affected_registers,
+ &registers_to_pop,
+ &registers_to_clear);
+ if (cp_offset_ != 0)
+ assembler->AdvanceCurrentPosition(cp_offset_);
+
+ // Create a new trivial state and generate the node with that.
+ jit::Label undo;
+ assembler->PushBacktrack(&undo);
+ Trace new_state;
+ successor->Emit(compiler, &new_state);
+
+ // On backtrack we need to restore state.
+ assembler->BindBacktrack(&undo);
+ RestoreAffectedRegisters(assembler,
+ max_register,
+ registers_to_pop,
+ registers_to_clear);
+ if (backtrack() == nullptr) {
+ assembler->Backtrack();
+ } else {
+ assembler->PopCurrentPosition();
+ assembler->JumpOrBacktrack(backtrack());
+ }
+}
+
+void
+Trace::InvalidateCurrentCharacter()
+{
+ characters_preloaded_ = 0;
+}
+
+void
+Trace::AdvanceCurrentPositionInTrace(int by, RegExpCompiler* compiler)
+{
+ MOZ_ASSERT(by > 0);
+ // We don't have an instruction for shifting the current character register
+ // down or for using a shifted value for anything so lets just forget that
+ // we preloaded any characters into it.
+ characters_preloaded_ = 0;
+ // Adjust the offsets of the quick check performed information. This
+ // information is used to find out what we already determined about the
+ // characters by means of mask and compare.
+ quick_check_performed_.Advance(by, compiler->ascii());
+ cp_offset_ += by;
+ if (cp_offset_ > RegExpMacroAssembler::kMaxCPOffset) {
+ compiler->SetRegExpTooBig();
+ cp_offset_ = 0;
+ }
+ bound_checked_up_to_ = Max(0, bound_checked_up_to_ - by);
+}
+
+void
+OutSet::Set(LifoAlloc* alloc, unsigned value)
+{
+ if (value < kFirstLimit) {
+ first_ |= (1 << value);
+ } else {
+ if (remaining_ == nullptr)
+ remaining_ = alloc->newInfallible<RemainingVector>(*alloc);
+
+ for (size_t i = 0; i < remaining().length(); i++) {
+ if (remaining()[i] == value)
+ return;
+ }
+ remaining().append(value);
+ }
+}
+
+bool
+OutSet::Get(unsigned value)
+{
+ if (value < kFirstLimit)
+ return (first_ & (1 << value)) != 0;
+ if (remaining_ == nullptr)
+ return false;
+ for (size_t i = 0; i < remaining().length(); i++) {
+ if (remaining()[i] == value)
+ return true;
+ }
+ return false;
+}
+
+// -------------------------------------------------------------------
+// Graph emitting
+
+void
+NegativeSubmatchSuccess::Emit(RegExpCompiler* compiler, Trace* trace)
+{
+ RegExpMacroAssembler* assembler = compiler->macro_assembler();
+
+ // Omit flushing the trace. We discard the entire stack frame anyway.
+
+ if (!label()->bound()) {
+ // We are completely independent of the trace, since we ignore it,
+ // so this code can be used as the generic version.
+ assembler->Bind(label());
+ }
+
+ // Throw away everything on the backtrack stack since the start
+ // of the negative submatch and restore the character position.
+ assembler->ReadCurrentPositionFromRegister(current_position_register_);
+ assembler->ReadBacktrackStackPointerFromRegister(stack_pointer_register_);
+
+ if (clear_capture_count_ > 0) {
+ // Clear any captures that might have been performed during the success
+ // of the body of the negative look-ahead.
+ int clear_capture_end = clear_capture_start_ + clear_capture_count_ - 1;
+ assembler->ClearRegisters(clear_capture_start_, clear_capture_end);
+ }
+
+ // Now that we have unwound the stack we find at the top of the stack the
+ // backtrack that the BeginSubmatch node got.
+ assembler->Backtrack();
+}
+
+void
+EndNode::Emit(RegExpCompiler* compiler, Trace* trace)
+{
+ if (!trace->is_trivial()) {
+ trace->Flush(compiler, this);
+ return;
+ }
+ RegExpMacroAssembler* assembler = compiler->macro_assembler();
+ if (!label()->bound()) {
+ assembler->Bind(label());
+ }
+ switch (action_) {
+ case ACCEPT:
+ assembler->Succeed();
+ return;
+ case BACKTRACK:
+ assembler->JumpOrBacktrack(trace->backtrack());
+ return;
+ case NEGATIVE_SUBMATCH_SUCCESS:
+ // This case is handled in a different virtual method.
+ MOZ_CRASH("Bad action: NEGATIVE_SUBMATCH_SUCCESS");
+ }
+ MOZ_CRASH("Bad action");
+}
+
+// Emit the code to check for a ^ in multiline mode (1-character lookbehind
+// that matches newline or the start of input).
+static void
+EmitHat(RegExpCompiler* compiler, RegExpNode* on_success, Trace* trace)
+{
+ RegExpMacroAssembler* assembler = compiler->macro_assembler();
+
+ // We will be loading the previous character into the current character
+ // register.
+ Trace new_trace(*trace);
+ new_trace.InvalidateCurrentCharacter();
+
+ jit::Label ok;
+ if (new_trace.cp_offset() == 0) {
+ // The start of input counts as a newline in this context, so skip to
+ // ok if we are at the start.
+ assembler->CheckAtStart(&ok);
+ }
+
+ // We already checked that we are not at the start of input so it must be
+ // OK to load the previous character.
+ assembler->LoadCurrentCharacter(new_trace.cp_offset() -1, new_trace.backtrack(), false);
+
+ if (!assembler->CheckSpecialCharacterClass('n', new_trace.backtrack())) {
+ // Newline means \n, \r, 0x2028 or 0x2029.
+ if (!compiler->ascii())
+ assembler->CheckCharacterAfterAnd(0x2028, 0xfffe, &ok);
+ assembler->CheckCharacter('\n', &ok);
+ assembler->CheckNotCharacter('\r', new_trace.backtrack());
+ }
+ assembler->Bind(&ok);
+ on_success->Emit(compiler, &new_trace);
+}
+
+// Assert that the next character cannot be a part of a surrogate pair.
+static void
+EmitNotAfterLeadSurrogate(RegExpCompiler* compiler, RegExpNode* on_success, Trace* trace)
+{
+ RegExpMacroAssembler* assembler = compiler->macro_assembler();
+
+ // We will be loading the previous character into the current character
+ // register.
+ Trace new_trace(*trace);
+ new_trace.InvalidateCurrentCharacter();
+
+ jit::Label ok;
+ if (new_trace.cp_offset() == 0)
+ assembler->CheckAtStart(&ok);
+
+ // We already checked that we are not at the start of input so it must be
+ // OK to load the previous character.
+ assembler->LoadCurrentCharacter(new_trace.cp_offset() - 1, new_trace.backtrack(), false);
+ assembler->CheckCharacterInRange(unicode::LeadSurrogateMin, unicode::LeadSurrogateMax,
+ new_trace.backtrack());
+
+ assembler->Bind(&ok);
+ on_success->Emit(compiler, &new_trace);
+}
+
+// Assert that the next character is not a trail surrogate that has a
+// corresponding lead surrogate.
+static void
+EmitNotInSurrogatePair(RegExpCompiler* compiler, RegExpNode* on_success, Trace* trace)
+{
+ RegExpMacroAssembler* assembler = compiler->macro_assembler();
+
+ jit::Label ok;
+ assembler->CheckPosition(trace->cp_offset(), &ok);
+
+ // We will be loading the next and previous characters into the current
+ // character register.
+ Trace new_trace(*trace);
+ new_trace.InvalidateCurrentCharacter();
+
+ if (new_trace.cp_offset() == 0)
+ assembler->CheckAtStart(&ok);
+
+ // First check if next character is a trail surrogate.
+ assembler->LoadCurrentCharacter(new_trace.cp_offset(), new_trace.backtrack(), false);
+ assembler->CheckCharacterNotInRange(unicode::TrailSurrogateMin, unicode::TrailSurrogateMax,
+ &ok);
+
+ // Next check if previous character is a lead surrogate.
+ // We already checked that we are not at the start of input so it must be
+ // OK to load the previous character.
+ assembler->LoadCurrentCharacter(new_trace.cp_offset() - 1, new_trace.backtrack(), false);
+ assembler->CheckCharacterInRange(unicode::LeadSurrogateMin, unicode::LeadSurrogateMax,
+ new_trace.backtrack());
+
+ assembler->Bind(&ok);
+ on_success->Emit(compiler, &new_trace);
+}
+
+// Check for [0-9A-Z_a-z].
+static void
+EmitWordCheck(RegExpMacroAssembler* assembler,
+ jit::Label* word, jit::Label* non_word, bool fall_through_on_word)
+{
+ if (assembler->CheckSpecialCharacterClass(fall_through_on_word ? 'w' : 'W',
+ fall_through_on_word ? non_word : word))
+ {
+ // Optimized implementation available.
+ return;
+ }
+
+ assembler->CheckCharacterGT('z', non_word);
+ assembler->CheckCharacterLT('0', non_word);
+ assembler->CheckCharacterGT('a' - 1, word);
+ assembler->CheckCharacterLT('9' + 1, word);
+ assembler->CheckCharacterLT('A', non_word);
+ assembler->CheckCharacterLT('Z' + 1, word);
+
+ if (fall_through_on_word)
+ assembler->CheckNotCharacter('_', non_word);
+ else
+ assembler->CheckCharacter('_', word);
+}
+
+// Emit the code to handle \b and \B (word-boundary or non-word-boundary).
+void
+AssertionNode::EmitBoundaryCheck(RegExpCompiler* compiler, Trace* trace)
+{
+ RegExpMacroAssembler* assembler = compiler->macro_assembler();
+ Trace::TriBool next_is_word_character = Trace::UNKNOWN;
+ bool not_at_start = (trace->at_start() == Trace::FALSE_VALUE);
+ BoyerMooreLookahead* lookahead = bm_info(not_at_start);
+ if (lookahead == nullptr) {
+ int eats_at_least =
+ Min(kMaxLookaheadForBoyerMoore, EatsAtLeast(kMaxLookaheadForBoyerMoore,
+ kRecursionBudget,
+ not_at_start));
+ if (eats_at_least >= 1) {
+ BoyerMooreLookahead* bm =
+ alloc()->newInfallible<BoyerMooreLookahead>(alloc(), eats_at_least, compiler);
+ FillInBMInfo(0, kRecursionBudget, bm, not_at_start);
+ if (bm->at(0)->is_non_word())
+ next_is_word_character = Trace::FALSE_VALUE;
+ if (bm->at(0)->is_word()) next_is_word_character = Trace::TRUE_VALUE;
+ }
+ } else {
+ if (lookahead->at(0)->is_non_word())
+ next_is_word_character = Trace::FALSE_VALUE;
+ if (lookahead->at(0)->is_word())
+ next_is_word_character = Trace::TRUE_VALUE;
+ }
+ bool at_boundary = (assertion_type_ == AssertionNode::AT_BOUNDARY);
+ if (next_is_word_character == Trace::UNKNOWN) {
+ jit::Label before_non_word;
+ jit::Label before_word;
+ if (trace->characters_preloaded() != 1) {
+ assembler->LoadCurrentCharacter(trace->cp_offset(), &before_non_word);
+ }
+ // Fall through on non-word.
+ EmitWordCheck(assembler, &before_word, &before_non_word, false);
+ // Next character is not a word character.
+ assembler->Bind(&before_non_word);
+ jit::Label ok;
+ BacktrackIfPrevious(compiler, trace, at_boundary ? kIsNonWord : kIsWord);
+ assembler->JumpOrBacktrack(&ok);
+
+ assembler->Bind(&before_word);
+ BacktrackIfPrevious(compiler, trace, at_boundary ? kIsWord : kIsNonWord);
+ assembler->Bind(&ok);
+ } else if (next_is_word_character == Trace::TRUE_VALUE) {
+ BacktrackIfPrevious(compiler, trace, at_boundary ? kIsWord : kIsNonWord);
+ } else {
+ MOZ_ASSERT(next_is_word_character == Trace::FALSE_VALUE);
+ BacktrackIfPrevious(compiler, trace, at_boundary ? kIsNonWord : kIsWord);
+ }
+}
+
+void
+AssertionNode::BacktrackIfPrevious(RegExpCompiler* compiler,
+ Trace* trace,
+ AssertionNode::IfPrevious backtrack_if_previous)
+{
+ RegExpMacroAssembler* assembler = compiler->macro_assembler();
+ Trace new_trace(*trace);
+ new_trace.InvalidateCurrentCharacter();
+
+ jit::Label fall_through, dummy;
+
+ jit::Label* non_word = backtrack_if_previous == kIsNonWord ? new_trace.backtrack() : &fall_through;
+ jit::Label* word = backtrack_if_previous == kIsNonWord ? &fall_through : new_trace.backtrack();
+
+ if (new_trace.cp_offset() == 0) {
+ // The start of input counts as a non-word character, so the question is
+ // decided if we are at the start.
+ assembler->CheckAtStart(non_word);
+ }
+ // We already checked that we are not at the start of input so it must be
+ // OK to load the previous character.
+ assembler->LoadCurrentCharacter(new_trace.cp_offset() - 1, &dummy, false);
+ EmitWordCheck(assembler, word, non_word, backtrack_if_previous == kIsNonWord);
+
+ assembler->Bind(&fall_through);
+ on_success()->Emit(compiler, &new_trace);
+}
+
+void
+AssertionNode::GetQuickCheckDetails(QuickCheckDetails* details,
+ RegExpCompiler* compiler,
+ int filled_in,
+ bool not_at_start)
+{
+ if (assertion_type_ == AT_START && not_at_start) {
+ details->set_cannot_match();
+ return;
+ }
+ return on_success()->GetQuickCheckDetails(details, compiler, filled_in, not_at_start);
+}
+
+void
+AssertionNode::Emit(RegExpCompiler* compiler, Trace* trace)
+{
+ RegExpMacroAssembler* assembler = compiler->macro_assembler();
+ switch (assertion_type_) {
+ case AT_END: {
+ jit::Label ok;
+ assembler->CheckPosition(trace->cp_offset(), &ok);
+ assembler->JumpOrBacktrack(trace->backtrack());
+ assembler->Bind(&ok);
+ break;
+ }
+ case AT_START: {
+ if (trace->at_start() == Trace::FALSE_VALUE) {
+ assembler->JumpOrBacktrack(trace->backtrack());
+ return;
+ }
+ if (trace->at_start() == Trace::UNKNOWN) {
+ assembler->CheckNotAtStart(trace->backtrack());
+ Trace at_start_trace = *trace;
+ at_start_trace.set_at_start(true);
+ on_success()->Emit(compiler, &at_start_trace);
+ return;
+ }
+ }
+ break;
+ case AFTER_NEWLINE:
+ EmitHat(compiler, on_success(), trace);
+ return;
+ case AT_BOUNDARY:
+ case AT_NON_BOUNDARY: {
+ EmitBoundaryCheck(compiler, trace);
+ return;
+ }
+ case NOT_AFTER_LEAD_SURROGATE:
+ EmitNotAfterLeadSurrogate(compiler, on_success(), trace);
+ return;
+ case NOT_IN_SURROGATE_PAIR:
+ EmitNotInSurrogatePair(compiler, on_success(), trace);
+ return;
+ }
+ on_success()->Emit(compiler, trace);
+}
+
+static bool
+DeterminedAlready(QuickCheckDetails* quick_check, int offset)
+{
+ if (quick_check == nullptr)
+ return false;
+ if (offset >= quick_check->characters())
+ return false;
+ return quick_check->positions(offset)->determines_perfectly;
+}
+
+static void
+UpdateBoundsCheck(int index, int* checked_up_to)
+{
+ if (index > *checked_up_to)
+ *checked_up_to = index;
+}
+
+static void
+EmitBoundaryTest(RegExpMacroAssembler* masm,
+ int border,
+ jit::Label* fall_through,
+ jit::Label* above_or_equal,
+ jit::Label* below)
+{
+ if (below != fall_through) {
+ masm->CheckCharacterLT(border, below);
+ if (above_or_equal != fall_through)
+ masm->JumpOrBacktrack(above_or_equal);
+ } else {
+ masm->CheckCharacterGT(border - 1, above_or_equal);
+ }
+}
+
+static void
+EmitDoubleBoundaryTest(RegExpMacroAssembler* masm,
+ int first,
+ int last,
+ jit::Label* fall_through,
+ jit::Label* in_range,
+ jit::Label* out_of_range)
+{
+ if (in_range == fall_through) {
+ if (first == last)
+ masm->CheckNotCharacter(first, out_of_range);
+ else
+ masm->CheckCharacterNotInRange(first, last, out_of_range);
+ } else {
+ if (first == last)
+ masm->CheckCharacter(first, in_range);
+ else
+ masm->CheckCharacterInRange(first, last, in_range);
+ if (out_of_range != fall_through)
+ masm->JumpOrBacktrack(out_of_range);
+ }
+}
+
+typedef InfallibleVector<int, 4> RangeBoundaryVector;
+
+// even_label is for ranges[i] to ranges[i + 1] where i - start_index is even.
+// odd_label is for ranges[i] to ranges[i + 1] where i - start_index is odd.
+static void
+EmitUseLookupTable(RegExpMacroAssembler* masm,
+ RangeBoundaryVector& ranges,
+ int start_index,
+ int end_index,
+ int min_char,
+ jit::Label* fall_through,
+ jit::Label* even_label,
+ jit::Label* odd_label)
+{
+ static const int kSize = RegExpMacroAssembler::kTableSize;
+ static const int kMask = RegExpMacroAssembler::kTableMask;
+
+ DebugOnly<int> base = (min_char & ~kMask);
+
+ // Assert that everything is on one kTableSize page.
+ for (int i = start_index; i <= end_index; i++)
+ MOZ_ASSERT((ranges[i] & ~kMask) == base);
+ MOZ_ASSERT(start_index == 0 || (ranges[start_index - 1] & ~kMask) <= base);
+
+ char templ[kSize];
+ jit::Label* on_bit_set;
+ jit::Label* on_bit_clear;
+ int bit;
+ if (even_label == fall_through) {
+ on_bit_set = odd_label;
+ on_bit_clear = even_label;
+ bit = 1;
+ } else {
+ on_bit_set = even_label;
+ on_bit_clear = odd_label;
+ bit = 0;
+ }
+ for (int i = 0; i < (ranges[start_index] & kMask) && i < kSize; i++)
+ templ[i] = bit;
+ int j = 0;
+ bit ^= 1;
+ for (int i = start_index; i < end_index; i++) {
+ for (j = (ranges[i] & kMask); j < (ranges[i + 1] & kMask); j++) {
+ templ[j] = bit;
+ }
+ bit ^= 1;
+ }
+ for (int i = j; i < kSize; i++) {
+ templ[i] = bit;
+ }
+
+ // TODO(erikcorry): Cache these.
+ uint8_t* ba;
+ {
+ AutoEnterOOMUnsafeRegion oomUnsafe;
+ ba = static_cast<uint8_t*>(js_malloc(kSize));
+ if (!ba || !masm->shared->addTable(ba))
+ oomUnsafe.crash("Table malloc");
+ }
+
+ for (int i = 0; i < kSize; i++)
+ ba[i] = templ[i];
+
+ masm->CheckBitInTable(ba, on_bit_set);
+ if (on_bit_clear != fall_through)
+ masm->JumpOrBacktrack(on_bit_clear);
+}
+
+static void
+CutOutRange(RegExpMacroAssembler* masm,
+ RangeBoundaryVector& ranges,
+ int start_index,
+ int end_index,
+ int cut_index,
+ jit::Label* even_label,
+ jit::Label* odd_label)
+{
+ bool odd = (((cut_index - start_index) & 1) == 1);
+ jit::Label* in_range_label = odd ? odd_label : even_label;
+ jit::Label dummy;
+ EmitDoubleBoundaryTest(masm,
+ ranges[cut_index],
+ ranges[cut_index + 1] - 1,
+ &dummy,
+ in_range_label,
+ &dummy);
+ MOZ_ASSERT(!dummy.used());
+ // Cut out the single range by rewriting the array. This creates a new
+ // range that is a merger of the two ranges on either side of the one we
+ // are cutting out. The oddity of the labels is preserved.
+ for (int j = cut_index; j > start_index; j--)
+ ranges[j] = ranges[j - 1];
+ for (int j = cut_index + 1; j < end_index; j++)
+ ranges[j] = ranges[j + 1];
+}
+
+// Unicode case. Split the search space into kSize spaces that are handled
+// with recursion.
+static void
+SplitSearchSpace(RangeBoundaryVector& ranges,
+ int start_index,
+ int end_index,
+ int* new_start_index,
+ int* new_end_index,
+ int* border)
+{
+ static const int kSize = RegExpMacroAssembler::kTableSize;
+ static const int kMask = RegExpMacroAssembler::kTableMask;
+
+ int first = ranges[start_index];
+ int last = ranges[end_index] - 1;
+
+ *new_start_index = start_index;
+ *border = (ranges[start_index] & ~kMask) + kSize;
+ while (*new_start_index < end_index) {
+ if (ranges[*new_start_index] > *border)
+ break;
+ (*new_start_index)++;
+ }
+ // new_start_index is the index of the first edge that is beyond the
+ // current kSize space.
+
+ // For very large search spaces we do a binary chop search of the non-ASCII
+ // space instead of just going to the end of the current kSize space. The
+ // heuristics are complicated a little by the fact that any 128-character
+ // encoding space can be quickly tested with a table lookup, so we don't
+ // wish to do binary chop search at a smaller granularity than that. A
+ // 128-character space can take up a lot of space in the ranges array if,
+ // for example, we only want to match every second character (eg. the lower
+ // case characters on some Unicode pages).
+ int binary_chop_index = (end_index + start_index) / 2;
+ // The first test ensures that we get to the code that handles the ASCII
+ // range with a single not-taken branch, speeding up this important
+ // character range (even non-ASCII charset-based text has spaces and
+ // punctuation).
+ if (*border - 1 > kMaxOneByteCharCode && // ASCII case.
+ end_index - start_index > (*new_start_index - start_index) * 2 &&
+ last - first > kSize * 2 &&
+ binary_chop_index > *new_start_index &&
+ ranges[binary_chop_index] >= first + 2 * kSize)
+ {
+ int scan_forward_for_section_border = binary_chop_index;;
+ int new_border = (ranges[binary_chop_index] | kMask) + 1;
+
+ while (scan_forward_for_section_border < end_index) {
+ if (ranges[scan_forward_for_section_border] > new_border) {
+ *new_start_index = scan_forward_for_section_border;
+ *border = new_border;
+ break;
+ }
+ scan_forward_for_section_border++;
+ }
+ }
+
+ MOZ_ASSERT(*new_start_index > start_index);
+ *new_end_index = *new_start_index - 1;
+ if (ranges[*new_end_index] == *border)
+ (*new_end_index)--;
+ if (*border >= ranges[end_index]) {
+ *border = ranges[end_index];
+ *new_start_index = end_index; // Won't be used.
+ *new_end_index = end_index - 1;
+ }
+}
+
+// Gets a series of segment boundaries representing a character class. If the
+// character is in the range between an even and an odd boundary (counting from
+// start_index) then go to even_label, otherwise go to odd_label. We already
+// know that the character is in the range of min_char to max_char inclusive.
+// Either label can be nullptr indicating backtracking. Either label can also be
+// equal to the fall_through label.
+static void
+GenerateBranches(RegExpMacroAssembler* masm,
+ RangeBoundaryVector& ranges,
+ int start_index,
+ int end_index,
+ char16_t min_char,
+ char16_t max_char,
+ jit::Label* fall_through,
+ jit::Label* even_label,
+ jit::Label* odd_label)
+{
+ int first = ranges[start_index];
+ int last = ranges[end_index] - 1;
+
+ MOZ_ASSERT(min_char < first);
+
+ // Just need to test if the character is before or on-or-after
+ // a particular character.
+ if (start_index == end_index) {
+ EmitBoundaryTest(masm, first, fall_through, even_label, odd_label);
+ return;
+ }
+
+ // Another almost trivial case: There is one interval in the middle that is
+ // different from the end intervals.
+ if (start_index + 1 == end_index) {
+ EmitDoubleBoundaryTest(masm, first, last, fall_through, even_label, odd_label);
+ return;
+ }
+
+ // It's not worth using table lookup if there are very few intervals in the
+ // character class.
+ if (end_index - start_index <= 6) {
+ // It is faster to test for individual characters, so we look for those
+ // first, then try arbitrary ranges in the second round.
+ static int kNoCutIndex = -1;
+ int cut = kNoCutIndex;
+ for (int i = start_index; i < end_index; i++) {
+ if (ranges[i] == ranges[i + 1] - 1) {
+ cut = i;
+ break;
+ }
+ }
+ if (cut == kNoCutIndex) cut = start_index;
+ CutOutRange(masm, ranges, start_index, end_index, cut, even_label, odd_label);
+ MOZ_ASSERT(end_index - start_index >= 2);
+ GenerateBranches(masm,
+ ranges,
+ start_index + 1,
+ end_index - 1,
+ min_char,
+ max_char,
+ fall_through,
+ even_label,
+ odd_label);
+ return;
+ }
+
+ // If there are a lot of intervals in the regexp, then we will use tables to
+ // determine whether the character is inside or outside the character class.
+ static const int kBits = RegExpMacroAssembler::kTableSizeBits;
+
+ if ((max_char >> kBits) == (min_char >> kBits)) {
+ EmitUseLookupTable(masm,
+ ranges,
+ start_index,
+ end_index,
+ min_char,
+ fall_through,
+ even_label,
+ odd_label);
+ return;
+ }
+
+ if ((min_char >> kBits) != (first >> kBits)) {
+ masm->CheckCharacterLT(first, odd_label);
+ GenerateBranches(masm,
+ ranges,
+ start_index + 1,
+ end_index,
+ first,
+ max_char,
+ fall_through,
+ odd_label,
+ even_label);
+ return;
+ }
+
+ int new_start_index = 0;
+ int new_end_index = 0;
+ int border = 0;
+
+ SplitSearchSpace(ranges,
+ start_index,
+ end_index,
+ &new_start_index,
+ &new_end_index,
+ &border);
+
+ jit::Label handle_rest;
+ jit::Label* above = &handle_rest;
+ if (border == last + 1) {
+ // We didn't find any section that started after the limit, so everything
+ // above the border is one of the terminal labels.
+ above = (end_index & 1) != (start_index & 1) ? odd_label : even_label;
+ MOZ_ASSERT(new_end_index == end_index - 1);
+ }
+
+ MOZ_ASSERT(start_index <= new_end_index);
+ MOZ_ASSERT(new_start_index <= end_index);
+ MOZ_ASSERT(start_index < new_start_index);
+ MOZ_ASSERT(new_end_index < end_index);
+ MOZ_ASSERT(new_end_index + 1 == new_start_index ||
+ (new_end_index + 2 == new_start_index &&
+ border == ranges[new_end_index + 1]));
+ MOZ_ASSERT(min_char < border - 1);
+ MOZ_ASSERT(border < max_char);
+ MOZ_ASSERT(ranges[new_end_index] < border);
+ MOZ_ASSERT(border < ranges[new_start_index] ||
+ (border == ranges[new_start_index] &&
+ new_start_index == end_index &&
+ new_end_index == end_index - 1 &&
+ border == last + 1));
+ MOZ_ASSERT(new_start_index == 0 || border >= ranges[new_start_index - 1]);
+
+ masm->CheckCharacterGT(border - 1, above);
+ jit::Label dummy;
+ GenerateBranches(masm,
+ ranges,
+ start_index,
+ new_end_index,
+ min_char,
+ border - 1,
+ &dummy,
+ even_label,
+ odd_label);
+ if (handle_rest.used()) {
+ masm->Bind(&handle_rest);
+ bool flip = (new_start_index & 1) != (start_index & 1);
+ GenerateBranches(masm,
+ ranges,
+ new_start_index,
+ end_index,
+ border,
+ max_char,
+ &dummy,
+ flip ? odd_label : even_label,
+ flip ? even_label : odd_label);
+ }
+}
+
+static void
+EmitCharClass(LifoAlloc* alloc,
+ RegExpMacroAssembler* macro_assembler,
+ RegExpCharacterClass* cc,
+ bool ascii,
+ jit::Label* on_failure,
+ int cp_offset,
+ bool check_offset,
+ bool preloaded)
+{
+ CharacterRangeVector& ranges = cc->ranges(alloc);
+ if (!CharacterRange::IsCanonical(ranges)) {
+ CharacterRange::Canonicalize(ranges);
+ }
+
+ int max_char = MaximumCharacter(ascii);
+ int range_count = ranges.length();
+
+ int last_valid_range = range_count - 1;
+ while (last_valid_range >= 0) {
+ CharacterRange& range = ranges[last_valid_range];
+ if (range.from() <= max_char) {
+ break;
+ }
+ last_valid_range--;
+ }
+
+ if (last_valid_range < 0) {
+ if (!cc->is_negated()) {
+ macro_assembler->JumpOrBacktrack(on_failure);
+ }
+ if (check_offset) {
+ macro_assembler->CheckPosition(cp_offset, on_failure);
+ }
+ return;
+ }
+
+ if (last_valid_range == 0 &&
+ ranges[0].IsEverything(max_char)) {
+ if (cc->is_negated()) {
+ macro_assembler->JumpOrBacktrack(on_failure);
+ } else {
+ // This is a common case hit by non-anchored expressions.
+ if (check_offset) {
+ macro_assembler->CheckPosition(cp_offset, on_failure);
+ }
+ }
+ return;
+ }
+ if (last_valid_range == 0 &&
+ !cc->is_negated() &&
+ ranges[0].IsEverything(max_char)) {
+ // This is a common case hit by non-anchored expressions.
+ if (check_offset) {
+ macro_assembler->CheckPosition(cp_offset, on_failure);
+ }
+ return;
+ }
+
+ if (!preloaded) {
+ macro_assembler->LoadCurrentCharacter(cp_offset, on_failure, check_offset);
+ }
+
+ if (cc->is_standard(alloc) &&
+ macro_assembler->CheckSpecialCharacterClass(cc->standard_type(),
+ on_failure)) {
+ return;
+ }
+
+ // A new list with ascending entries. Each entry is a code unit
+ // where there is a boundary between code units that are part of
+ // the class and code units that are not. Normally we insert an
+ // entry at zero which goes to the failure label, but if there
+ // was already one there we fall through for success on that entry.
+ // Subsequent entries have alternating meaning (success/failure).
+ RangeBoundaryVector* range_boundaries =
+ alloc->newInfallible<RangeBoundaryVector>(*alloc);
+
+ bool zeroth_entry_is_failure = !cc->is_negated();
+
+ range_boundaries->reserve(last_valid_range);
+ for (int i = 0; i <= last_valid_range; i++) {
+ CharacterRange& range = ranges[i];
+ if (range.from() == 0) {
+ MOZ_ASSERT(i == 0);
+ zeroth_entry_is_failure = !zeroth_entry_is_failure;
+ } else {
+ range_boundaries->append(range.from());
+ }
+ range_boundaries->append(range.to() + 1);
+ }
+ int end_index = range_boundaries->length() - 1;
+ if ((*range_boundaries)[end_index] > max_char)
+ end_index--;
+
+ jit::Label fall_through;
+ GenerateBranches(macro_assembler,
+ *range_boundaries,
+ 0, // start_index.
+ end_index,
+ 0, // min_char.
+ max_char,
+ &fall_through,
+ zeroth_entry_is_failure ? &fall_through : on_failure,
+ zeroth_entry_is_failure ? on_failure : &fall_through);
+ macro_assembler->Bind(&fall_through);
+}
+
+typedef bool EmitCharacterFunction(RegExpCompiler* compiler,
+ char16_t c,
+ jit::Label* on_failure,
+ int cp_offset,
+ bool check,
+ bool preloaded);
+
+static inline bool
+EmitSimpleCharacter(RegExpCompiler* compiler,
+ char16_t c,
+ jit::Label* on_failure,
+ int cp_offset,
+ bool check,
+ bool preloaded)
+{
+ RegExpMacroAssembler* assembler = compiler->macro_assembler();
+ bool bound_checked = false;
+ if (!preloaded) {
+ assembler->LoadCurrentCharacter(cp_offset, on_failure, check);
+ bound_checked = true;
+ }
+ assembler->CheckNotCharacter(c, on_failure);
+ return bound_checked;
+}
+
+// Only emits non-letters (things that don't have case). Only used for case
+// independent matches.
+static inline bool
+EmitAtomNonLetter(RegExpCompiler* compiler,
+ char16_t c,
+ jit::Label* on_failure,
+ int cp_offset,
+ bool check,
+ bool preloaded)
+{
+ RegExpMacroAssembler* macro_assembler = compiler->macro_assembler();
+ bool ascii = compiler->ascii();
+ char16_t chars[kEcma262UnCanonicalizeMaxWidth];
+ int length = GetCaseIndependentLetters(c, ascii, compiler->unicode(), chars);
+ if (length < 1) {
+ // This can't match. Must be an ASCII subject and a non-ASCII character.
+ // We do not need to do anything since the ASCII pass already handled this.
+ return false; // Bounds not checked.
+ }
+ bool checked = false;
+ // We handle the length > 1 case in a later pass.
+ if (length == 1) {
+ if (ascii && c > kMaxOneByteCharCode) {
+ // Can't match - see above.
+ return false; // Bounds not checked.
+ }
+ if (!preloaded) {
+ macro_assembler->LoadCurrentCharacter(cp_offset, on_failure, check);
+ checked = check;
+ }
+ macro_assembler->CheckNotCharacter(c, on_failure);
+ }
+ return checked;
+}
+
+static bool
+ShortCutEmitCharacterPair(RegExpMacroAssembler* macro_assembler,
+ bool ascii,
+ char16_t c1,
+ char16_t c2,
+ jit::Label* on_failure)
+{
+ char16_t char_mask = MaximumCharacter(ascii);
+
+ MOZ_ASSERT(c1 != c2);
+ if (c1 > c2) {
+ char16_t tmp = c1;
+ c1 = c2;
+ c2 = tmp;
+ }
+
+ char16_t exor = c1 ^ c2;
+ // Check whether exor has only one bit set.
+ if (((exor - 1) & exor) == 0) {
+ // If c1 and c2 differ only by one bit.
+ char16_t mask = char_mask ^ exor;
+ macro_assembler->CheckNotCharacterAfterAnd(c1, mask, on_failure);
+ return true;
+ }
+
+ char16_t diff = c2 - c1;
+ if (((diff - 1) & diff) == 0 && c1 >= diff) {
+ // If the characters differ by 2^n but don't differ by one bit then
+ // subtract the difference from the found character, then do the or
+ // trick. We avoid the theoretical case where negative numbers are
+ // involved in order to simplify code generation.
+ char16_t mask = char_mask ^ diff;
+ macro_assembler->CheckNotCharacterAfterMinusAnd(c1 - diff,
+ diff,
+ mask,
+ on_failure);
+ return true;
+ }
+ return false;
+}
+
+// Only emits letters (things that have case). Only used for case independent
+// matches.
+static inline bool
+EmitAtomLetter(RegExpCompiler* compiler,
+ char16_t c,
+ jit::Label* on_failure,
+ int cp_offset,
+ bool check,
+ bool preloaded)
+{
+ RegExpMacroAssembler* macro_assembler = compiler->macro_assembler();
+ bool ascii = compiler->ascii();
+ char16_t chars[kEcma262UnCanonicalizeMaxWidth];
+ int length = GetCaseIndependentLetters(c, ascii, compiler->unicode(), chars);
+ if (length <= 1) return false;
+ // We may not need to check against the end of the input string
+ // if this character lies before a character that matched.
+ if (!preloaded)
+ macro_assembler->LoadCurrentCharacter(cp_offset, on_failure, check);
+ jit::Label ok;
+ MOZ_ASSERT(kEcma262UnCanonicalizeMaxWidth == 4);
+ switch (length) {
+ case 2: {
+ if (ShortCutEmitCharacterPair(macro_assembler,
+ ascii,
+ chars[0],
+ chars[1],
+ on_failure)) {
+ } else {
+ macro_assembler->CheckCharacter(chars[0], &ok);
+ macro_assembler->CheckNotCharacter(chars[1], on_failure);
+ macro_assembler->Bind(&ok);
+ }
+ break;
+ }
+ case 4:
+ macro_assembler->CheckCharacter(chars[3], &ok);
+ MOZ_FALLTHROUGH;
+ case 3:
+ macro_assembler->CheckCharacter(chars[0], &ok);
+ macro_assembler->CheckCharacter(chars[1], &ok);
+ macro_assembler->CheckNotCharacter(chars[2], on_failure);
+ macro_assembler->Bind(&ok);
+ break;
+ default:
+ MOZ_CRASH("Bad length");
+ }
+ return true;
+}
+
+// We call this repeatedly to generate code for each pass over the text node.
+// The passes are in increasing order of difficulty because we hope one
+// of the first passes will fail in which case we are saved the work of the
+// later passes. for example for the case independent regexp /%[asdfghjkl]a/
+// we will check the '%' in the first pass, the case independent 'a' in the
+// second pass and the character class in the last pass.
+//
+// The passes are done from right to left, so for example to test for /bar/
+// we will first test for an 'r' with offset 2, then an 'a' with offset 1
+// and then a 'b' with offset 0. This means we can avoid the end-of-input
+// bounds check most of the time. In the example we only need to check for
+// end-of-input when loading the putative 'r'.
+//
+// A slight complication involves the fact that the first character may already
+// be fetched into a register by the previous node. In this case we want to
+// do the test for that character first. We do this in separate passes. The
+// 'preloaded' argument indicates that we are doing such a 'pass'. If such a
+// pass has been performed then subsequent passes will have true in
+// first_element_checked to indicate that that character does not need to be
+// checked again.
+//
+// In addition to all this we are passed a Trace, which can
+// contain an AlternativeGeneration object. In this AlternativeGeneration
+// object we can see details of any quick check that was already passed in
+// order to get to the code we are now generating. The quick check can involve
+// loading characters, which means we do not need to recheck the bounds
+// up to the limit the quick check already checked. In addition the quick
+// check can have involved a mask and compare operation which may simplify
+// or obviate the need for further checks at some character positions.
+void
+TextNode::TextEmitPass(RegExpCompiler* compiler,
+ TextEmitPassType pass,
+ bool preloaded,
+ Trace* trace,
+ bool first_element_checked,
+ int* checked_up_to)
+{
+ RegExpMacroAssembler* assembler = compiler->macro_assembler();
+ bool ascii = compiler->ascii();
+ jit::Label* backtrack = trace->backtrack();
+ QuickCheckDetails* quick_check = trace->quick_check_performed();
+ int element_count = elements().length();
+ for (int i = preloaded ? 0 : element_count - 1; i >= 0; i--) {
+ TextElement elm = elements()[i];
+ int cp_offset = trace->cp_offset() + elm.cp_offset();
+ if (elm.text_type() == TextElement::ATOM) {
+ const CharacterVector& quarks = elm.atom()->data();
+ for (int j = preloaded ? 0 : quarks.length() - 1; j >= 0; j--) {
+ if (first_element_checked && i == 0 && j == 0) continue;
+ if (DeterminedAlready(quick_check, elm.cp_offset() + j)) continue;
+ EmitCharacterFunction* emit_function = nullptr;
+ switch (pass) {
+ case NON_ASCII_MATCH:
+ MOZ_ASSERT(ascii);
+ if (quarks[j] > kMaxOneByteCharCode) {
+ assembler->JumpOrBacktrack(backtrack);
+ return;
+ }
+ break;
+ case NON_LETTER_CHARACTER_MATCH:
+ emit_function = &EmitAtomNonLetter;
+ break;
+ case SIMPLE_CHARACTER_MATCH:
+ emit_function = &EmitSimpleCharacter;
+ break;
+ case CASE_CHARACTER_MATCH:
+ emit_function = &EmitAtomLetter;
+ break;
+ default:
+ break;
+ }
+ if (emit_function != nullptr) {
+ bool bound_checked = emit_function(compiler,
+ quarks[j],
+ backtrack,
+ cp_offset + j,
+ *checked_up_to < cp_offset + j,
+ preloaded);
+ if (bound_checked) UpdateBoundsCheck(cp_offset + j, checked_up_to);
+ }
+ }
+ } else {
+ MOZ_ASSERT(TextElement::CHAR_CLASS == elm.text_type());
+ if (pass == CHARACTER_CLASS_MATCH) {
+ if (first_element_checked && i == 0) continue;
+ if (DeterminedAlready(quick_check, elm.cp_offset())) continue;
+ RegExpCharacterClass* cc = elm.char_class();
+ EmitCharClass(alloc(),
+ assembler,
+ cc,
+ ascii,
+ backtrack,
+ cp_offset,
+ *checked_up_to < cp_offset,
+ preloaded);
+ UpdateBoundsCheck(cp_offset, checked_up_to);
+ }
+ }
+ }
+}
+
+int
+TextNode::Length()
+{
+ TextElement elm = elements()[elements().length() - 1];
+ MOZ_ASSERT(elm.cp_offset() >= 0);
+ return elm.cp_offset() + elm.length();
+}
+
+bool
+TextNode::SkipPass(int int_pass, bool ignore_case)
+{
+ TextEmitPassType pass = static_cast<TextEmitPassType>(int_pass);
+ if (ignore_case)
+ return pass == SIMPLE_CHARACTER_MATCH;
+ return pass == NON_LETTER_CHARACTER_MATCH || pass == CASE_CHARACTER_MATCH;
+}
+
+// This generates the code to match a text node. A text node can contain
+// straight character sequences (possibly to be matched in a case-independent
+// way) and character classes. For efficiency we do not do this in a single
+// pass from left to right. Instead we pass over the text node several times,
+// emitting code for some character positions every time. See the comment on
+// TextEmitPass for details.
+void
+TextNode::Emit(RegExpCompiler* compiler, Trace* trace)
+{
+ LimitResult limit_result = LimitVersions(compiler, trace);
+ if (limit_result == DONE) return;
+ MOZ_ASSERT(limit_result == CONTINUE);
+
+ if (trace->cp_offset() + Length() > RegExpMacroAssembler::kMaxCPOffset) {
+ compiler->SetRegExpTooBig();
+ return;
+ }
+
+ if (compiler->ascii()) {
+ int dummy = 0;
+ TextEmitPass(compiler, NON_ASCII_MATCH, false, trace, false, &dummy);
+ }
+
+ bool first_elt_done = false;
+ int bound_checked_to = trace->cp_offset() - 1;
+ bound_checked_to += trace->bound_checked_up_to();
+
+ // If a character is preloaded into the current character register then
+ // check that now.
+ if (trace->characters_preloaded() == 1) {
+ for (int pass = kFirstRealPass; pass <= kLastPass; pass++) {
+ if (!SkipPass(pass, compiler->ignore_case())) {
+ TextEmitPass(compiler,
+ static_cast<TextEmitPassType>(pass),
+ true,
+ trace,
+ false,
+ &bound_checked_to);
+ }
+ }
+ first_elt_done = true;
+ }
+
+ for (int pass = kFirstRealPass; pass <= kLastPass; pass++) {
+ if (!SkipPass(pass, compiler->ignore_case())) {
+ TextEmitPass(compiler,
+ static_cast<TextEmitPassType>(pass),
+ false,
+ trace,
+ first_elt_done,
+ &bound_checked_to);
+ }
+ }
+
+ Trace successor_trace(*trace);
+ successor_trace.set_at_start(false);
+ successor_trace.AdvanceCurrentPositionInTrace(Length(), compiler);
+ RecursionCheck rc(compiler);
+ on_success()->Emit(compiler, &successor_trace);
+}
+
+void
+LoopChoiceNode::Emit(RegExpCompiler* compiler, Trace* trace)
+{
+ RegExpMacroAssembler* macro_assembler = compiler->macro_assembler();
+ if (trace->stop_node() == this) {
+ int text_length =
+ GreedyLoopTextLengthForAlternative(&alternatives()[0]);
+ MOZ_ASSERT(text_length != kNodeIsTooComplexForGreedyLoops);
+ // Update the counter-based backtracking info on the stack. This is an
+ // optimization for greedy loops (see below).
+ MOZ_ASSERT(trace->cp_offset() == text_length);
+ macro_assembler->AdvanceCurrentPosition(text_length);
+ macro_assembler->JumpOrBacktrack(trace->loop_label());
+ return;
+ }
+ MOZ_ASSERT(trace->stop_node() == nullptr);
+ if (!trace->is_trivial()) {
+ trace->Flush(compiler, this);
+ return;
+ }
+ ChoiceNode::Emit(compiler, trace);
+}
+
+/* Code generation for choice nodes.
+ *
+ * We generate quick checks that do a mask and compare to eliminate a
+ * choice. If the quick check succeeds then it jumps to the continuation to
+ * do slow checks and check subsequent nodes. If it fails (the common case)
+ * it falls through to the next choice.
+ *
+ * Here is the desired flow graph. Nodes directly below each other imply
+ * fallthrough. Alternatives 1 and 2 have quick checks. Alternative
+ * 3 doesn't have a quick check so we have to call the slow check.
+ * Nodes are marked Qn for quick checks and Sn for slow checks. The entire
+ * regexp continuation is generated directly after the Sn node, up to the
+ * next JumpOrBacktrack if we decide to reuse some already generated code. Some
+ * nodes expect preload_characters to be preloaded into the current
+ * character register. R nodes do this preloading. Vertices are marked
+ * F for failures and S for success (possible success in the case of quick
+ * nodes). L, V, < and > are used as arrow heads.
+ *
+ * ----------> R
+ * |
+ * V
+ * Q1 -----> S1
+ * | S /
+ * F| /
+ * | F/
+ * | /
+ * | R
+ * | /
+ * V L
+ * Q2 -----> S2
+ * | S /
+ * F| /
+ * | F/
+ * | /
+ * | R
+ * | /
+ * V L
+ * S3
+ * |
+ * F|
+ * |
+ * R
+ * |
+ * backtrack V
+ * <----------Q4
+ * \ F |
+ * \ |S
+ * \ F V
+ * \-----S4
+ *
+ * For greedy loops we reverse our expectation and expect to match rather
+ * than fail. Therefore we want the loop code to look like this (U is the
+ * unwind code that steps back in the greedy loop). The following alternatives
+ * look the same as above.
+ * _____
+ * / \
+ * V |
+ * ----------> S1 |
+ * /| |
+ * / |S |
+ * F/ \_____/
+ * /
+ * |<-----------
+ * | \
+ * V \
+ * Q2 ---> S2 \
+ * | S / |
+ * F| / |
+ * | F/ |
+ * | / |
+ * | R |
+ * | / |
+ * F VL |
+ * <------U |
+ * back |S |
+ * \______________/
+ */
+
+// This class is used when generating the alternatives in a choice node. It
+// records the way the alternative is being code generated.
+class irregexp::AlternativeGeneration
+{
+ public:
+ AlternativeGeneration()
+ : possible_success(),
+ expects_preload(false),
+ after(),
+ quick_check_details()
+ {}
+
+ jit::Label possible_success;
+ bool expects_preload;
+ jit::Label after;
+ QuickCheckDetails quick_check_details;
+};
+
+void
+ChoiceNode::GenerateGuard(RegExpMacroAssembler* macro_assembler,
+ Guard* guard, Trace* trace)
+{
+ switch (guard->op()) {
+ case Guard::LT:
+ MOZ_ASSERT(!trace->mentions_reg(guard->reg()));
+ macro_assembler->IfRegisterGE(guard->reg(),
+ guard->value(),
+ trace->backtrack());
+ break;
+ case Guard::GEQ:
+ MOZ_ASSERT(!trace->mentions_reg(guard->reg()));
+ macro_assembler->IfRegisterLT(guard->reg(),
+ guard->value(),
+ trace->backtrack());
+ break;
+ }
+}
+
+int
+ChoiceNode::CalculatePreloadCharacters(RegExpCompiler* compiler, int eats_at_least)
+{
+ int preload_characters = Min(4, eats_at_least);
+ if (compiler->macro_assembler()->CanReadUnaligned()) {
+ bool ascii = compiler->ascii();
+ if (ascii) {
+ if (preload_characters > 4)
+ preload_characters = 4;
+ // We can't preload 3 characters because there is no machine instruction
+ // to do that. We can't just load 4 because we could be reading
+ // beyond the end of the string, which could cause a memory fault.
+ if (preload_characters == 3)
+ preload_characters = 2;
+ } else {
+ if (preload_characters > 2)
+ preload_characters = 2;
+ }
+ } else {
+ if (preload_characters > 1)
+ preload_characters = 1;
+ }
+ return preload_characters;
+}
+
+RegExpNode*
+TextNode::GetSuccessorOfOmnivorousTextNode(RegExpCompiler* compiler)
+{
+ if (elements().length() != 1)
+ return nullptr;
+
+ TextElement elm = elements()[0];
+ if (elm.text_type() != TextElement::CHAR_CLASS)
+ return nullptr;
+
+ RegExpCharacterClass* node = elm.char_class();
+ CharacterRangeVector& ranges = node->ranges(alloc());
+
+ if (!CharacterRange::IsCanonical(ranges))
+ CharacterRange::Canonicalize(ranges);
+
+ if (node->is_negated())
+ return ranges.length() == 0 ? on_success() : nullptr;
+
+ if (ranges.length() != 1)
+ return nullptr;
+
+ uint32_t max_char = MaximumCharacter(compiler->ascii());
+ return ranges[0].IsEverything(max_char) ? on_success() : nullptr;
+}
+
+// Finds the fixed match length of a sequence of nodes that goes from
+// this alternative and back to this choice node. If there are variable
+// length nodes or other complications in the way then return a sentinel
+// value indicating that a greedy loop cannot be constructed.
+int
+ChoiceNode::GreedyLoopTextLengthForAlternative(GuardedAlternative* alternative)
+{
+ int length = 0;
+ RegExpNode* node = alternative->node();
+ // Later we will generate code for all these text nodes using recursion
+ // so we have to limit the max number.
+ int recursion_depth = 0;
+ while (node != this) {
+ if (recursion_depth++ > RegExpCompiler::kMaxRecursion) {
+ return kNodeIsTooComplexForGreedyLoops;
+ }
+ int node_length = node->GreedyLoopTextLength();
+ if (node_length == kNodeIsTooComplexForGreedyLoops) {
+ return kNodeIsTooComplexForGreedyLoops;
+ }
+ length += node_length;
+ SeqRegExpNode* seq_node = static_cast<SeqRegExpNode*>(node);
+ node = seq_node->on_success();
+ }
+ return length;
+}
+
+// Creates a list of AlternativeGenerations. If the list has a reasonable
+// size then it is on the stack, otherwise the excess is on the heap.
+class AlternativeGenerationList
+{
+ public:
+ AlternativeGenerationList(LifoAlloc* alloc, size_t count)
+ : alt_gens_(*alloc)
+ {
+ alt_gens_.reserve(count);
+ for (size_t i = 0; i < count && i < kAFew; i++)
+ alt_gens_.append(a_few_alt_gens_ + i);
+ for (size_t i = kAFew; i < count; i++) {
+ AutoEnterOOMUnsafeRegion oomUnsafe;
+ AlternativeGeneration* gen = js_new<AlternativeGeneration>();
+ if (!gen)
+ oomUnsafe.crash("AlternativeGenerationList js_new");
+ alt_gens_.append(gen);
+ }
+ }
+
+ ~AlternativeGenerationList() {
+ for (size_t i = kAFew; i < alt_gens_.length(); i++) {
+ js_delete(alt_gens_[i]);
+ alt_gens_[i] = nullptr;
+ }
+ }
+
+ AlternativeGeneration* at(int i) {
+ return alt_gens_[i];
+ }
+
+ private:
+ static const size_t kAFew = 10;
+ InfallibleVector<AlternativeGeneration*, 1> alt_gens_;
+ AlternativeGeneration a_few_alt_gens_[kAFew];
+};
+
+void
+ChoiceNode::Emit(RegExpCompiler* compiler, Trace* trace)
+{
+ RegExpMacroAssembler* macro_assembler = compiler->macro_assembler();
+ size_t choice_count = alternatives().length();
+#ifdef DEBUG
+ for (size_t i = 0; i < choice_count - 1; i++) {
+ const GuardedAlternative& alternative = alternatives()[i];
+ const GuardVector* guards = alternative.guards();
+ if (guards) {
+ for (size_t j = 0; j < guards->length(); j++)
+ MOZ_ASSERT(!trace->mentions_reg((*guards)[j]->reg()));
+ }
+ }
+#endif
+
+ LimitResult limit_result = LimitVersions(compiler, trace);
+ if (limit_result == DONE) return;
+ MOZ_ASSERT(limit_result == CONTINUE);
+
+ int new_flush_budget = trace->flush_budget() / choice_count;
+ if (trace->flush_budget() == 0 && trace->actions() != nullptr) {
+ trace->Flush(compiler, this);
+ return;
+ }
+
+ RecursionCheck rc(compiler);
+
+ Trace* current_trace = trace;
+
+ int text_length = GreedyLoopTextLengthForAlternative(&alternatives()[0]);
+ bool greedy_loop = false;
+ jit::Label greedy_loop_label;
+ Trace counter_backtrack_trace;
+ counter_backtrack_trace.set_backtrack(&greedy_loop_label);
+ if (not_at_start()) counter_backtrack_trace.set_at_start(false);
+
+ if (choice_count > 1 && text_length != kNodeIsTooComplexForGreedyLoops) {
+ // Here we have special handling for greedy loops containing only text nodes
+ // and other simple nodes. These are handled by pushing the current
+ // position on the stack and then incrementing the current position each
+ // time around the switch. On backtrack we decrement the current position
+ // and check it against the pushed value. This avoids pushing backtrack
+ // information for each iteration of the loop, which could take up a lot of
+ // space.
+ greedy_loop = true;
+ MOZ_ASSERT(trace->stop_node() == nullptr);
+ macro_assembler->PushCurrentPosition();
+ current_trace = &counter_backtrack_trace;
+ jit::Label greedy_match_failed;
+ Trace greedy_match_trace;
+ if (not_at_start()) greedy_match_trace.set_at_start(false);
+ greedy_match_trace.set_backtrack(&greedy_match_failed);
+ jit::Label loop_label;
+ macro_assembler->Bind(&loop_label);
+ greedy_match_trace.set_stop_node(this);
+ greedy_match_trace.set_loop_label(&loop_label);
+ alternatives()[0].node()->Emit(compiler, &greedy_match_trace);
+ macro_assembler->Bind(&greedy_match_failed);
+ }
+
+ jit::Label second_choice; // For use in greedy matches.
+ macro_assembler->Bind(&second_choice);
+
+ size_t first_normal_choice = greedy_loop ? 1 : 0;
+
+ bool not_at_start = current_trace->at_start() == Trace::FALSE_VALUE;
+ const int kEatsAtLeastNotYetInitialized = -1;
+ int eats_at_least = kEatsAtLeastNotYetInitialized;
+
+ bool skip_was_emitted = false;
+
+ if (!greedy_loop && choice_count == 2) {
+ GuardedAlternative alt1 = alternatives()[1];
+ if (!alt1.guards() || alt1.guards()->length() == 0) {
+ RegExpNode* eats_anything_node = alt1.node();
+ if (eats_anything_node->GetSuccessorOfOmnivorousTextNode(compiler) == this) {
+ // At this point we know that we are at a non-greedy loop that will eat
+ // any character one at a time. Any non-anchored regexp has such a
+ // loop prepended to it in order to find where it starts. We look for
+ // a pattern of the form ...abc... where we can look 6 characters ahead
+ // and step forwards 3 if the character is not one of abc. Abc need
+ // not be atoms, they can be any reasonably limited character class or
+ // small alternation.
+ MOZ_ASSERT(trace->is_trivial()); // This is the case on LoopChoiceNodes.
+ BoyerMooreLookahead* lookahead = bm_info(not_at_start);
+ if (lookahead == nullptr) {
+ eats_at_least = Min(kMaxLookaheadForBoyerMoore,
+ EatsAtLeast(kMaxLookaheadForBoyerMoore,
+ kRecursionBudget,
+ not_at_start));
+ if (eats_at_least >= 1) {
+ BoyerMooreLookahead* bm =
+ alloc()->newInfallible<BoyerMooreLookahead>(alloc(), eats_at_least, compiler);
+ GuardedAlternative alt0 = alternatives()[0];
+ alt0.node()->FillInBMInfo(0, kRecursionBudget, bm, not_at_start);
+ skip_was_emitted = bm->EmitSkipInstructions(macro_assembler);
+ }
+ } else {
+ skip_was_emitted = lookahead->EmitSkipInstructions(macro_assembler);
+ }
+ }
+ }
+ }
+
+ if (eats_at_least == kEatsAtLeastNotYetInitialized) {
+ // Save some time by looking at most one machine word ahead.
+ eats_at_least =
+ EatsAtLeast(compiler->ascii() ? 4 : 2, kRecursionBudget, not_at_start);
+ }
+ int preload_characters = CalculatePreloadCharacters(compiler, eats_at_least);
+
+ bool preload_is_current = !skip_was_emitted &&
+ (current_trace->characters_preloaded() == preload_characters);
+ bool preload_has_checked_bounds = preload_is_current;
+
+ AlternativeGenerationList alt_gens(alloc(), choice_count);
+
+ // For now we just call all choices one after the other. The idea ultimately
+ // is to use the Dispatch table to try only the relevant ones.
+ for (size_t i = first_normal_choice; i < choice_count; i++) {
+ GuardedAlternative alternative = alternatives()[i];
+ AlternativeGeneration* alt_gen = alt_gens.at(i);
+ alt_gen->quick_check_details.set_characters(preload_characters);
+ const GuardVector* guards = alternative.guards();
+ Trace new_trace(*current_trace);
+ new_trace.set_characters_preloaded(preload_is_current ?
+ preload_characters :
+ 0);
+ if (preload_has_checked_bounds) {
+ new_trace.set_bound_checked_up_to(preload_characters);
+ }
+ new_trace.quick_check_performed()->Clear();
+ if (not_at_start_) new_trace.set_at_start(Trace::FALSE_VALUE);
+ alt_gen->expects_preload = preload_is_current;
+ bool generate_full_check_inline = false;
+ if (try_to_emit_quick_check_for_alternative(i) &&
+ alternative.node()->EmitQuickCheck(compiler,
+ &new_trace,
+ preload_has_checked_bounds,
+ &alt_gen->possible_success,
+ &alt_gen->quick_check_details,
+ i < choice_count - 1)) {
+ // Quick check was generated for this choice.
+ preload_is_current = true;
+ preload_has_checked_bounds = true;
+ // On the last choice in the ChoiceNode we generated the quick
+ // check to fall through on possible success. So now we need to
+ // generate the full check inline.
+ if (i == choice_count - 1) {
+ macro_assembler->Bind(&alt_gen->possible_success);
+ new_trace.set_quick_check_performed(&alt_gen->quick_check_details);
+ new_trace.set_characters_preloaded(preload_characters);
+ new_trace.set_bound_checked_up_to(preload_characters);
+ generate_full_check_inline = true;
+ }
+ } else if (alt_gen->quick_check_details.cannot_match()) {
+ if (i == choice_count - 1 && !greedy_loop) {
+ macro_assembler->JumpOrBacktrack(trace->backtrack());
+ }
+ continue;
+ } else {
+ // No quick check was generated. Put the full code here.
+ // If this is not the first choice then there could be slow checks from
+ // previous cases that go here when they fail. There's no reason to
+ // insist that they preload characters since the slow check we are about
+ // to generate probably can't use it.
+ if (i != first_normal_choice) {
+ alt_gen->expects_preload = false;
+ new_trace.InvalidateCurrentCharacter();
+ }
+ if (i < choice_count - 1) {
+ new_trace.set_backtrack(&alt_gen->after);
+ }
+ generate_full_check_inline = true;
+ }
+ if (generate_full_check_inline) {
+ if (new_trace.actions() != nullptr)
+ new_trace.set_flush_budget(new_flush_budget);
+ if (guards) {
+ for (size_t j = 0; j < guards->length(); j++)
+ GenerateGuard(macro_assembler, (*guards)[j], &new_trace);
+ }
+ alternative.node()->Emit(compiler, &new_trace);
+ preload_is_current = false;
+ }
+ macro_assembler->Bind(&alt_gen->after);
+ }
+ if (greedy_loop) {
+ macro_assembler->Bind(&greedy_loop_label);
+ // If we have unwound to the bottom then backtrack.
+ macro_assembler->CheckGreedyLoop(trace->backtrack());
+ // Otherwise try the second priority at an earlier position.
+ macro_assembler->AdvanceCurrentPosition(-text_length);
+ macro_assembler->JumpOrBacktrack(&second_choice);
+ }
+
+ // At this point we need to generate slow checks for the alternatives where
+ // the quick check was inlined. We can recognize these because the associated
+ // label was bound.
+ for (size_t i = first_normal_choice; i < choice_count - 1; i++) {
+ AlternativeGeneration* alt_gen = alt_gens.at(i);
+ Trace new_trace(*current_trace);
+ // If there are actions to be flushed we have to limit how many times
+ // they are flushed. Take the budget of the parent trace and distribute
+ // it fairly amongst the children.
+ if (new_trace.actions() != nullptr) {
+ new_trace.set_flush_budget(new_flush_budget);
+ }
+ EmitOutOfLineContinuation(compiler,
+ &new_trace,
+ alternatives()[i],
+ alt_gen,
+ preload_characters,
+ alt_gens.at(i + 1)->expects_preload);
+ }
+}
+
+void
+ChoiceNode::EmitOutOfLineContinuation(RegExpCompiler* compiler,
+ Trace* trace,
+ GuardedAlternative alternative,
+ AlternativeGeneration* alt_gen,
+ int preload_characters,
+ bool next_expects_preload)
+{
+ if (!alt_gen->possible_success.used())
+ return;
+
+ RegExpMacroAssembler* macro_assembler = compiler->macro_assembler();
+ macro_assembler->Bind(&alt_gen->possible_success);
+ Trace out_of_line_trace(*trace);
+ out_of_line_trace.set_characters_preloaded(preload_characters);
+ out_of_line_trace.set_quick_check_performed(&alt_gen->quick_check_details);
+ if (not_at_start_) out_of_line_trace.set_at_start(Trace::FALSE_VALUE);
+ const GuardVector* guards = alternative.guards();
+ if (next_expects_preload) {
+ jit::Label reload_current_char;
+ out_of_line_trace.set_backtrack(&reload_current_char);
+ if (guards) {
+ for (size_t j = 0; j < guards->length(); j++)
+ GenerateGuard(macro_assembler, (*guards)[j], &out_of_line_trace);
+ }
+ alternative.node()->Emit(compiler, &out_of_line_trace);
+ macro_assembler->Bind(&reload_current_char);
+ // Reload the current character, since the next quick check expects that.
+ // We don't need to check bounds here because we only get into this
+ // code through a quick check which already did the checked load.
+ macro_assembler->LoadCurrentCharacter(trace->cp_offset(),
+ nullptr,
+ false,
+ preload_characters);
+ macro_assembler->JumpOrBacktrack(&(alt_gen->after));
+ } else {
+ out_of_line_trace.set_backtrack(&(alt_gen->after));
+ if (guards) {
+ for (size_t j = 0; j < guards->length(); j++)
+ GenerateGuard(macro_assembler, (*guards)[j], &out_of_line_trace);
+ }
+ alternative.node()->Emit(compiler, &out_of_line_trace);
+ }
+}
+
+void
+ActionNode::Emit(RegExpCompiler* compiler, Trace* trace)
+{
+ RegExpMacroAssembler* assembler = compiler->macro_assembler();
+ LimitResult limit_result = LimitVersions(compiler, trace);
+ if (limit_result == DONE) return;
+ MOZ_ASSERT(limit_result == CONTINUE);
+
+ RecursionCheck rc(compiler);
+
+ switch (action_type_) {
+ case STORE_POSITION: {
+ Trace::DeferredCapture
+ new_capture(data_.u_position_register.reg,
+ data_.u_position_register.is_capture,
+ trace);
+ Trace new_trace = *trace;
+ new_trace.add_action(&new_capture);
+ on_success()->Emit(compiler, &new_trace);
+ break;
+ }
+ case INCREMENT_REGISTER: {
+ Trace::DeferredIncrementRegister
+ new_increment(data_.u_increment_register.reg);
+ Trace new_trace = *trace;
+ new_trace.add_action(&new_increment);
+ on_success()->Emit(compiler, &new_trace);
+ break;
+ }
+ case SET_REGISTER: {
+ Trace::DeferredSetRegister
+ new_set(data_.u_store_register.reg, data_.u_store_register.value);
+ Trace new_trace = *trace;
+ new_trace.add_action(&new_set);
+ on_success()->Emit(compiler, &new_trace);
+ break;
+ }
+ case CLEAR_CAPTURES: {
+ Trace::DeferredClearCaptures
+ new_capture(Interval(data_.u_clear_captures.range_from,
+ data_.u_clear_captures.range_to));
+ Trace new_trace = *trace;
+ new_trace.add_action(&new_capture);
+ on_success()->Emit(compiler, &new_trace);
+ break;
+ }
+ case BEGIN_SUBMATCH:
+ if (!trace->is_trivial()) {
+ trace->Flush(compiler, this);
+ } else {
+ assembler->WriteCurrentPositionToRegister(data_.u_submatch.current_position_register, 0);
+ assembler->WriteBacktrackStackPointerToRegister(data_.u_submatch.stack_pointer_register);
+ on_success()->Emit(compiler, trace);
+ }
+ break;
+ case EMPTY_MATCH_CHECK: {
+ int start_pos_reg = data_.u_empty_match_check.start_register;
+ int stored_pos = 0;
+ int rep_reg = data_.u_empty_match_check.repetition_register;
+ bool has_minimum = (rep_reg != RegExpCompiler::kNoRegister);
+ bool know_dist = trace->GetStoredPosition(start_pos_reg, &stored_pos);
+ if (know_dist && !has_minimum && stored_pos == trace->cp_offset()) {
+ // If we know we haven't advanced and there is no minimum we
+ // can just backtrack immediately.
+ assembler->JumpOrBacktrack(trace->backtrack());
+ } else if (know_dist && stored_pos < trace->cp_offset()) {
+ // If we know we've advanced we can generate the continuation
+ // immediately.
+ on_success()->Emit(compiler, trace);
+ } else if (!trace->is_trivial()) {
+ trace->Flush(compiler, this);
+ } else {
+ jit::Label skip_empty_check;
+ // If we have a minimum number of repetitions we check the current
+ // number first and skip the empty check if it's not enough.
+ if (has_minimum) {
+ int limit = data_.u_empty_match_check.repetition_limit;
+ assembler->IfRegisterLT(rep_reg, limit, &skip_empty_check);
+ }
+ // If the match is empty we bail out, otherwise we fall through
+ // to the on-success continuation.
+ assembler->IfRegisterEqPos(data_.u_empty_match_check.start_register,
+ trace->backtrack());
+ assembler->Bind(&skip_empty_check);
+ on_success()->Emit(compiler, trace);
+ }
+ break;
+ }
+ case POSITIVE_SUBMATCH_SUCCESS: {
+ if (!trace->is_trivial()) {
+ trace->Flush(compiler, this);
+ return;
+ }
+ assembler->ReadCurrentPositionFromRegister(data_.u_submatch.current_position_register);
+ assembler->ReadBacktrackStackPointerFromRegister(data_.u_submatch.stack_pointer_register);
+ int clear_register_count = data_.u_submatch.clear_register_count;
+ if (clear_register_count == 0) {
+ on_success()->Emit(compiler, trace);
+ return;
+ }
+ int clear_registers_from = data_.u_submatch.clear_register_from;
+ jit::Label clear_registers_backtrack;
+ Trace new_trace = *trace;
+ new_trace.set_backtrack(&clear_registers_backtrack);
+ on_success()->Emit(compiler, &new_trace);
+
+ assembler->Bind(&clear_registers_backtrack);
+ int clear_registers_to = clear_registers_from + clear_register_count - 1;
+ assembler->ClearRegisters(clear_registers_from, clear_registers_to);
+
+ MOZ_ASSERT(trace->backtrack() == nullptr);
+ assembler->Backtrack();
+ return;
+ }
+ default:
+ MOZ_CRASH("Bad action");
+ }
+}
+
+void
+BackReferenceNode::Emit(RegExpCompiler* compiler, Trace* trace)
+{
+ RegExpMacroAssembler* assembler = compiler->macro_assembler();
+ if (!trace->is_trivial()) {
+ trace->Flush(compiler, this);
+ return;
+ }
+
+ LimitResult limit_result = LimitVersions(compiler, trace);
+ if (limit_result == DONE) return;
+ MOZ_ASSERT(limit_result == CONTINUE);
+
+ RecursionCheck rc(compiler);
+
+ MOZ_ASSERT(start_reg_ + 1 == end_reg_);
+ if (compiler->ignore_case()) {
+ assembler->CheckNotBackReferenceIgnoreCase(start_reg_,
+ trace->backtrack(),
+ compiler->unicode());
+ } else {
+ assembler->CheckNotBackReference(start_reg_, trace->backtrack());
+ }
+ on_success()->Emit(compiler, trace);
+}
+
+RegExpNode::LimitResult
+RegExpNode::LimitVersions(RegExpCompiler* compiler, Trace* trace)
+{
+ // If we are generating a greedy loop then don't stop and don't reuse code.
+ if (trace->stop_node() != nullptr)
+ return CONTINUE;
+
+ RegExpMacroAssembler* macro_assembler = compiler->macro_assembler();
+ if (trace->is_trivial()) {
+ if (label()->bound()) {
+ // We are being asked to generate a generic version, but that's already
+ // been done so just go to it.
+ macro_assembler->JumpOrBacktrack(label());
+ return DONE;
+ }
+ if (compiler->recursion_depth() >= RegExpCompiler::kMaxRecursion) {
+ // To avoid too deep recursion we push the node to the work queue and just
+ // generate a goto here.
+ compiler->AddWork(this);
+ macro_assembler->JumpOrBacktrack(label());
+ return DONE;
+ }
+ // Generate generic version of the node and bind the label for later use.
+ macro_assembler->Bind(label());
+ return CONTINUE;
+ }
+
+ // We are being asked to make a non-generic version. Keep track of how many
+ // non-generic versions we generate so as not to overdo it.
+ trace_count_++;
+ if (trace_count_ < kMaxCopiesCodeGenerated &&
+ compiler->recursion_depth() <= RegExpCompiler::kMaxRecursion) {
+ return CONTINUE;
+ }
+
+ // If we get here code has been generated for this node too many times or
+ // recursion is too deep. Time to switch to a generic version. The code for
+ // generic versions above can handle deep recursion properly.
+ trace->Flush(compiler, this);
+ return DONE;
+}
+
+bool
+RegExpNode::EmitQuickCheck(RegExpCompiler* compiler,
+ Trace* trace,
+ bool preload_has_checked_bounds,
+ jit::Label* on_possible_success,
+ QuickCheckDetails* details,
+ bool fall_through_on_failure)
+{
+ if (details->characters() == 0) return false;
+ GetQuickCheckDetails(
+ details, compiler, 0, trace->at_start() == Trace::FALSE_VALUE);
+ if (details->cannot_match()) return false;
+ if (!details->Rationalize(compiler->ascii())) return false;
+ MOZ_ASSERT(details->characters() == 1 ||
+ compiler->macro_assembler()->CanReadUnaligned());
+ uint32_t mask = details->mask();
+ uint32_t value = details->value();
+
+ RegExpMacroAssembler* assembler = compiler->macro_assembler();
+
+ if (trace->characters_preloaded() != details->characters()) {
+ assembler->LoadCurrentCharacter(trace->cp_offset(),
+ trace->backtrack(),
+ !preload_has_checked_bounds,
+ details->characters());
+ }
+
+ bool need_mask = true;
+
+ if (details->characters() == 1) {
+ // If number of characters preloaded is 1 then we used a byte or 16 bit
+ // load so the value is already masked down.
+ uint32_t char_mask = MaximumCharacter(compiler->ascii());
+ if ((mask & char_mask) == char_mask) need_mask = false;
+ mask &= char_mask;
+ } else {
+ // For 2-character preloads in ASCII mode or 1-character preloads in
+ // TWO_BYTE mode we also use a 16 bit load with zero extend.
+ if (details->characters() == 2 && compiler->ascii()) {
+ if ((mask & 0xffff) == 0xffff) need_mask = false;
+ } else if (details->characters() == 1 && !compiler->ascii()) {
+ if ((mask & 0xffff) == 0xffff) need_mask = false;
+ } else {
+ if (mask == 0xffffffff) need_mask = false;
+ }
+ }
+
+ if (fall_through_on_failure) {
+ if (need_mask) {
+ assembler->CheckCharacterAfterAnd(value, mask, on_possible_success);
+ } else {
+ assembler->CheckCharacter(value, on_possible_success);
+ }
+ } else {
+ if (need_mask) {
+ assembler->CheckNotCharacterAfterAnd(value, mask, trace->backtrack());
+ } else {
+ assembler->CheckNotCharacter(value, trace->backtrack());
+ }
+ }
+ return true;
+}
+
+bool
+TextNode::FillInBMInfo(int initial_offset,
+ int budget,
+ BoyerMooreLookahead* bm,
+ bool not_at_start)
+{
+ if (!bm->CheckOverRecursed())
+ return false;
+
+ if (initial_offset >= bm->length())
+ return true;
+
+ int offset = initial_offset;
+ int max_char = bm->max_char();
+ for (size_t i = 0; i < elements().length(); i++) {
+ if (offset >= bm->length()) {
+ if (initial_offset == 0)
+ set_bm_info(not_at_start, bm);
+ return true;
+ }
+ TextElement text = elements()[i];
+ if (text.text_type() == TextElement::ATOM) {
+ RegExpAtom* atom = text.atom();
+ for (int j = 0; j < atom->length(); j++, offset++) {
+ if (offset >= bm->length()) {
+ if (initial_offset == 0)
+ set_bm_info(not_at_start, bm);
+ return true;
+ }
+ char16_t character = atom->data()[j];
+ if (bm->compiler()->ignore_case()) {
+ char16_t chars[kEcma262UnCanonicalizeMaxWidth];
+ int length = GetCaseIndependentLetters(character,
+ bm->max_char() == kMaxOneByteCharCode,
+ bm->compiler()->unicode(),
+ chars);
+ for (int j = 0; j < length; j++)
+ bm->Set(offset, chars[j]);
+ } else {
+ if (character <= max_char) bm->Set(offset, character);
+ }
+ }
+ } else {
+ MOZ_ASSERT(TextElement::CHAR_CLASS == text.text_type());
+ RegExpCharacterClass* char_class = text.char_class();
+ const CharacterRangeVector& ranges = char_class->ranges(alloc());
+ if (char_class->is_negated()) {
+ bm->SetAll(offset);
+ } else {
+ for (size_t k = 0; k < ranges.length(); k++) {
+ const CharacterRange& range = ranges[k];
+ if (range.from() > max_char)
+ continue;
+ int to = Min(max_char, static_cast<int>(range.to()));
+ bm->SetInterval(offset, Interval(range.from(), to));
+ }
+ }
+ offset++;
+ }
+ }
+ if (offset >= bm->length()) {
+ if (initial_offset == 0) set_bm_info(not_at_start, bm);
+ return true;
+ }
+ if (!on_success()->FillInBMInfo(offset,
+ budget - 1,
+ bm,
+ true)) // Not at start after a text node.
+ return false;
+ if (initial_offset == 0)
+ set_bm_info(not_at_start, bm);
+ return true;
+}
+
+// -------------------------------------------------------------------
+// QuickCheckDetails
+
+// Takes the left-most 1-bit and smears it out, setting all bits to its right.
+static inline uint32_t
+SmearBitsRight(uint32_t v)
+{
+ v |= v >> 1;
+ v |= v >> 2;
+ v |= v >> 4;
+ v |= v >> 8;
+ v |= v >> 16;
+ return v;
+}
+
+// Here is the meat of GetQuickCheckDetails (see also the comment on the
+// super-class in the .h file).
+//
+// We iterate along the text object, building up for each character a
+// mask and value that can be used to test for a quick failure to match.
+// The masks and values for the positions will be combined into a single
+// machine word for the current character width in order to be used in
+// generating a quick check.
+void
+TextNode::GetQuickCheckDetails(QuickCheckDetails* details,
+ RegExpCompiler* compiler,
+ int characters_filled_in,
+ bool not_at_start)
+{
+ MOZ_ASSERT(characters_filled_in < details->characters());
+ int characters = details->characters();
+ int char_mask = MaximumCharacter(compiler->ascii());
+
+ for (size_t k = 0; k < elements().length(); k++) {
+ TextElement elm = elements()[k];
+ if (elm.text_type() == TextElement::ATOM) {
+ const CharacterVector& quarks = elm.atom()->data();
+ for (size_t i = 0; i < (size_t) characters && i < quarks.length(); i++) {
+ QuickCheckDetails::Position* pos =
+ details->positions(characters_filled_in);
+ char16_t c = quarks[i];
+ if (c > char_mask) {
+ // If we expect a non-ASCII character from an ASCII string,
+ // there is no way we can match. Not even case independent
+ // matching can turn an ASCII character into non-ASCII or
+ // vice versa.
+ details->set_cannot_match();
+ pos->determines_perfectly = false;
+ return;
+ }
+ if (compiler->ignore_case()) {
+ char16_t chars[kEcma262UnCanonicalizeMaxWidth];
+ size_t length = GetCaseIndependentLetters(c, compiler->ascii(),
+ compiler->unicode(), chars);
+ MOZ_ASSERT(length != 0); // Can only happen if c > char_mask (see above).
+ if (length == 1) {
+ // This letter has no case equivalents, so it's nice and simple
+ // and the mask-compare will determine definitely whether we have
+ // a match at this character position.
+ pos->mask = char_mask;
+ pos->value = c;
+ pos->determines_perfectly = true;
+ } else {
+ uint32_t common_bits = char_mask;
+ uint32_t bits = chars[0];
+ for (size_t j = 1; j < length; j++) {
+ uint32_t differing_bits = ((chars[j] & common_bits) ^ bits);
+ common_bits ^= differing_bits;
+ bits &= common_bits;
+ }
+ // If length is 2 and common bits has only one zero in it then
+ // our mask and compare instruction will determine definitely
+ // whether we have a match at this character position. Otherwise
+ // it can only be an approximate check.
+ uint32_t one_zero = (common_bits | ~char_mask);
+ if (length == 2 && ((~one_zero) & ((~one_zero) - 1)) == 0) {
+ pos->determines_perfectly = true;
+ }
+ pos->mask = common_bits;
+ pos->value = bits;
+ }
+ } else {
+ // Don't ignore case. Nice simple case where the mask-compare will
+ // determine definitely whether we have a match at this character
+ // position.
+ pos->mask = char_mask;
+ pos->value = c;
+ pos->determines_perfectly = true;
+ }
+ characters_filled_in++;
+ MOZ_ASSERT(characters_filled_in <= details->characters());
+ if (characters_filled_in == details->characters()) {
+ return;
+ }
+ }
+ } else {
+ QuickCheckDetails::Position* pos =
+ details->positions(characters_filled_in);
+ RegExpCharacterClass* tree = elm.char_class();
+ const CharacterRangeVector& ranges = tree->ranges(alloc());
+ if (tree->is_negated()) {
+ // A quick check uses multi-character mask and compare. There is no
+ // useful way to incorporate a negative char class into this scheme
+ // so we just conservatively create a mask and value that will always
+ // succeed.
+ pos->mask = 0;
+ pos->value = 0;
+ } else {
+ size_t first_range = 0;
+ while (ranges[first_range].from() > char_mask) {
+ first_range++;
+ if (first_range == ranges.length()) {
+ details->set_cannot_match();
+ pos->determines_perfectly = false;
+ return;
+ }
+ }
+ CharacterRange range = ranges[first_range];
+ char16_t from = range.from();
+ char16_t to = range.to();
+ if (to > char_mask) {
+ to = char_mask;
+ }
+ uint32_t differing_bits = (from ^ to);
+ // A mask and compare is only perfect if the differing bits form a
+ // number like 00011111 with one single block of trailing 1s.
+ if ((differing_bits & (differing_bits + 1)) == 0 &&
+ from + differing_bits == to) {
+ pos->determines_perfectly = true;
+ }
+ uint32_t common_bits = ~SmearBitsRight(differing_bits);
+ uint32_t bits = (from & common_bits);
+ for (size_t i = first_range + 1; i < ranges.length(); i++) {
+ CharacterRange range = ranges[i];
+ char16_t from = range.from();
+ char16_t to = range.to();
+ if (from > char_mask) continue;
+ if (to > char_mask) to = char_mask;
+ // Here we are combining more ranges into the mask and compare
+ // value. With each new range the mask becomes more sparse and
+ // so the chances of a false positive rise. A character class
+ // with multiple ranges is assumed never to be equivalent to a
+ // mask and compare operation.
+ pos->determines_perfectly = false;
+ uint32_t new_common_bits = (from ^ to);
+ new_common_bits = ~SmearBitsRight(new_common_bits);
+ common_bits &= new_common_bits;
+ bits &= new_common_bits;
+ uint32_t differing_bits = (from & common_bits) ^ bits;
+ common_bits ^= differing_bits;
+ bits &= common_bits;
+ }
+ pos->mask = common_bits;
+ pos->value = bits;
+ }
+ characters_filled_in++;
+ MOZ_ASSERT(characters_filled_in <= details->characters());
+ if (characters_filled_in == details->characters()) {
+ return;
+ }
+ }
+ }
+ MOZ_ASSERT(characters_filled_in != details->characters());
+ if (!details->cannot_match()) {
+ on_success()-> GetQuickCheckDetails(details,
+ compiler,
+ characters_filled_in,
+ true);
+ }
+}
+
+void
+QuickCheckDetails::Clear()
+{
+ for (int i = 0; i < characters_; i++) {
+ positions_[i].mask = 0;
+ positions_[i].value = 0;
+ positions_[i].determines_perfectly = false;
+ }
+ characters_ = 0;
+}
+
+void
+QuickCheckDetails::Advance(int by, bool ascii)
+{
+ MOZ_ASSERT(by >= 0);
+ if (by >= characters_) {
+ Clear();
+ return;
+ }
+ for (int i = 0; i < characters_ - by; i++) {
+ positions_[i] = positions_[by + i];
+ }
+ for (int i = characters_ - by; i < characters_; i++) {
+ positions_[i].mask = 0;
+ positions_[i].value = 0;
+ positions_[i].determines_perfectly = false;
+ }
+ characters_ -= by;
+ // We could change mask_ and value_ here but we would never advance unless
+ // they had already been used in a check and they won't be used again because
+ // it would gain us nothing. So there's no point.
+}
+
+bool
+QuickCheckDetails::Rationalize(bool is_ascii)
+{
+ bool found_useful_op = false;
+ uint32_t char_mask = MaximumCharacter(is_ascii);
+
+ mask_ = 0;
+ value_ = 0;
+ int char_shift = 0;
+ for (int i = 0; i < characters_; i++) {
+ Position* pos = &positions_[i];
+ if ((pos->mask & kMaxOneByteCharCode) != 0)
+ found_useful_op = true;
+ mask_ |= (pos->mask & char_mask) << char_shift;
+ value_ |= (pos->value & char_mask) << char_shift;
+ char_shift += is_ascii ? 8 : 16;
+ }
+ return found_useful_op;
+}
+
+void QuickCheckDetails::Merge(QuickCheckDetails* other, int from_index)
+{
+ MOZ_ASSERT(characters_ == other->characters_);
+ if (other->cannot_match_)
+ return;
+ if (cannot_match_) {
+ *this = *other;
+ return;
+ }
+ for (int i = from_index; i < characters_; i++) {
+ QuickCheckDetails::Position* pos = positions(i);
+ QuickCheckDetails::Position* other_pos = other->positions(i);
+ if (pos->mask != other_pos->mask ||
+ pos->value != other_pos->value ||
+ !other_pos->determines_perfectly) {
+ // Our mask-compare operation will be approximate unless we have the
+ // exact same operation on both sides of the alternation.
+ pos->determines_perfectly = false;
+ }
+ pos->mask &= other_pos->mask;
+ pos->value &= pos->mask;
+ other_pos->value &= pos->mask;
+ char16_t differing_bits = (pos->value ^ other_pos->value);
+ pos->mask &= ~differing_bits;
+ pos->value &= pos->mask;
+ }
+}