/* -*- 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. #ifndef V8_JSREGEXP_H_ #define V8_JSREGEXP_H_ #include "jscntxt.h" #include "ds/SplayTree.h" #include "jit/Label.h" #include "vm/RegExpObject.h" namespace js { class MatchPairs; class RegExpShared; namespace jit { class Label; class JitCode; } namespace irregexp { class RegExpTree; class RegExpMacroAssembler; struct RegExpCompileData { RegExpCompileData() : tree(nullptr), simple(true), contains_anchor(false), capture_count(0) {} RegExpTree* tree; bool simple; bool contains_anchor; int capture_count; }; struct RegExpCode { jit::JitCode* jitCode; uint8_t* byteCode; RegExpCode() : jitCode(nullptr), byteCode(nullptr) {} bool empty() { return !jitCode && !byteCode; } void destroy() { js_free(byteCode); } }; RegExpCode 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); // Note: this may return RegExpRunStatus_Error if an interrupt was requested // while the code was executing. template <typename CharT> RegExpRunStatus ExecuteCode(JSContext* cx, jit::JitCode* codeBlock, const CharT* chars, size_t start, size_t length, MatchPairs* matches, size_t* endIndex); template <typename CharT> RegExpRunStatus InterpretCode(JSContext* cx, const uint8_t* byteCode, const CharT* chars, size_t start, size_t length, MatchPairs* matches, size_t* endIndex); #define FOR_EACH_NODE_TYPE(VISIT) \ VISIT(End) \ VISIT(Action) \ VISIT(Choice) \ VISIT(BackReference) \ VISIT(Assertion) \ VISIT(Text) #define FOR_EACH_REG_EXP_TREE_TYPE(VISIT) \ VISIT(Disjunction) \ VISIT(Alternative) \ VISIT(Assertion) \ VISIT(CharacterClass) \ VISIT(Atom) \ VISIT(Quantifier) \ VISIT(Capture) \ VISIT(Lookahead) \ VISIT(BackReference) \ VISIT(Empty) \ VISIT(Text) #define FORWARD_DECLARE(Name) class RegExp##Name; FOR_EACH_REG_EXP_TREE_TYPE(FORWARD_DECLARE) #undef FORWARD_DECLARE // InfallibleVector is like Vector, but all its methods are infallible (they // crash on OOM). We use this class instead of Vector to avoid a ton of // MOZ_MUST_USE warnings in irregexp code (imported from V8). template<typename T, size_t N> class InfallibleVector { Vector<T, N, LifoAllocPolicy<Infallible>> vector_; InfallibleVector(const InfallibleVector&) = delete; void operator=(const InfallibleVector&) = delete; public: explicit InfallibleVector(const LifoAllocPolicy<Infallible>& alloc) : vector_(alloc) {} void append(const T& t) { MOZ_ALWAYS_TRUE(vector_.append(t)); } void append(const T* begin, size_t length) { MOZ_ALWAYS_TRUE(vector_.append(begin, length)); } void clear() { vector_.clear(); } void popBack() { vector_.popBack(); } void reserve(size_t n) { MOZ_ALWAYS_TRUE(vector_.reserve(n)); } size_t length() const { return vector_.length(); } T popCopy() { return vector_.popCopy(); } T* begin() { return vector_.begin(); } const T* begin() const { return vector_.begin(); } T& operator[](size_t index) { return vector_[index]; } const T& operator[](size_t index) const { return vector_[index]; } InfallibleVector& operator=(InfallibleVector&& rhs) { vector_ = Move(rhs.vector_); return *this; } }; class CharacterRange; typedef InfallibleVector<CharacterRange, 1> CharacterRangeVector; // Represents code units in the range from from_ to to_, both ends are // inclusive. class CharacterRange { public: CharacterRange() : from_(0), to_(0) {} CharacterRange(char16_t from, char16_t to) : from_(from), to_(to) {} static void AddClassEscape(LifoAlloc* alloc, char16_t type, CharacterRangeVector* ranges); static void AddClassEscapeUnicode(LifoAlloc* alloc, char16_t type, CharacterRangeVector* ranges, bool ignoreCase); static inline CharacterRange Singleton(char16_t value) { return CharacterRange(value, value); } static inline CharacterRange Range(char16_t from, char16_t to) { MOZ_ASSERT(from <= to); return CharacterRange(from, to); } static inline CharacterRange Everything() { return CharacterRange(0, 0xFFFF); } bool Contains(char16_t i) { return from_ <= i && i <= to_; } char16_t from() const { return from_; } void set_from(char16_t value) { from_ = value; } char16_t to() const { return to_; } void set_to(char16_t value) { to_ = value; } bool is_valid() { return from_ <= to_; } bool IsEverything(char16_t max) { return from_ == 0 && to_ >= max; } bool IsSingleton() { return (from_ == to_); } void AddCaseEquivalents(bool is_ascii, bool unicode, CharacterRangeVector* ranges); static void Split(const LifoAlloc* alloc, CharacterRangeVector base, const Vector<int>& overlay, CharacterRangeVector* included, CharacterRangeVector* excluded); // Whether a range list is in canonical form: Ranges ordered by from value, // and ranges non-overlapping and non-adjacent. static bool IsCanonical(const CharacterRangeVector& ranges); // Convert range list to canonical form. The characters covered by the ranges // will still be the same, but no character is in more than one range, and // adjacent ranges are merged. The resulting list may be shorter than the // original, but cannot be longer. static void Canonicalize(CharacterRangeVector& ranges); // Negate the contents of a character range in canonical form. static void Negate(const LifoAlloc* alloc, CharacterRangeVector src, CharacterRangeVector* dst); static const int kStartMarker = (1 << 24); static const int kPayloadMask = (1 << 24) - 1; private: char16_t from_; char16_t to_; }; // A set of unsigned integers that behaves especially well on small // integers (< 32). class OutSet { public: OutSet() : first_(0), remaining_(nullptr), successors_(nullptr) {} OutSet* Extend(LifoAlloc* alloc, unsigned value); bool Get(unsigned value); static const unsigned kFirstLimit = 32; private: typedef InfallibleVector<OutSet*, 1> OutSetVector; typedef InfallibleVector<unsigned, 1> RemainingVector; // Destructively set a value in this set. In most cases you want // to use Extend instead to ensure that only one instance exists // that contains the same values. void Set(LifoAlloc* alloc, unsigned value); // The successors are a list of sets that contain the same values // as this set and the one more value that is not present in this // set. OutSetVector* successors() { return successors_; } OutSet(uint32_t first, RemainingVector* remaining) : first_(first), remaining_(remaining), successors_(nullptr) {} RemainingVector& remaining() { return *remaining_; } uint32_t first_; RemainingVector* remaining_; OutSetVector* successors_; friend class Trace; }; // A mapping from integers, specified as ranges, to a set of integers. // Used for mapping character ranges to choices. class DispatchTable { public: explicit DispatchTable(LifoAlloc* alloc) {} class Entry { public: Entry() : from_(0), to_(0), out_set_(nullptr) {} Entry(char16_t from, char16_t to, OutSet* out_set) : from_(from), to_(to), out_set_(out_set) {} char16_t from() { return from_; } char16_t to() { return to_; } void set_to(char16_t value) { to_ = value; } void AddValue(LifoAlloc* alloc, int value) { out_set_ = out_set_->Extend(alloc, value); } OutSet* out_set() { return out_set_; } private: char16_t from_; char16_t to_; OutSet* out_set_; }; void AddRange(LifoAlloc* alloc, CharacterRange range, int value); OutSet* Get(char16_t value); void Dump(); private: // There can't be a static empty set since it allocates its // successors in a LifoAlloc and caches them. OutSet* empty() { return &empty_; } OutSet empty_; }; class TextElement { public: enum TextType { ATOM, CHAR_CLASS }; static TextElement Atom(RegExpAtom* atom); static TextElement CharClass(RegExpCharacterClass* char_class); int cp_offset() const { return cp_offset_; } void set_cp_offset(int cp_offset) { cp_offset_ = cp_offset; } int length() const; TextType text_type() const { return text_type_; } RegExpTree* tree() const { return tree_; } RegExpAtom* atom() const { MOZ_ASSERT(text_type() == ATOM); return reinterpret_cast<RegExpAtom*>(tree()); } RegExpCharacterClass* char_class() const { MOZ_ASSERT(text_type() == CHAR_CLASS); return reinterpret_cast<RegExpCharacterClass*>(tree()); } private: TextElement(TextType text_type, RegExpTree* tree) : cp_offset_(-1), text_type_(text_type), tree_(tree) {} int cp_offset_; TextType text_type_; RegExpTree* tree_; }; typedef InfallibleVector<TextElement, 1> TextElementVector; class NodeVisitor; class RegExpCompiler; class Trace; class BoyerMooreLookahead; struct NodeInfo { NodeInfo() : being_analyzed(false), been_analyzed(false), follows_word_interest(false), follows_newline_interest(false), follows_start_interest(false), at_end(false), visited(false), replacement_calculated(false) {} // Returns true if the interests and assumptions of this node // matches the given one. bool Matches(NodeInfo* that) { return (at_end == that->at_end) && (follows_word_interest == that->follows_word_interest) && (follows_newline_interest == that->follows_newline_interest) && (follows_start_interest == that->follows_start_interest); } // Updates the interests of this node given the interests of the // node preceding it. void AddFromPreceding(NodeInfo* that) { at_end |= that->at_end; follows_word_interest |= that->follows_word_interest; follows_newline_interest |= that->follows_newline_interest; follows_start_interest |= that->follows_start_interest; } bool HasLookbehind() { return follows_word_interest || follows_newline_interest || follows_start_interest; } // Sets the interests of this node to include the interests of the // following node. void AddFromFollowing(NodeInfo* that) { follows_word_interest |= that->follows_word_interest; follows_newline_interest |= that->follows_newline_interest; follows_start_interest |= that->follows_start_interest; } void ResetCompilationState() { being_analyzed = false; been_analyzed = false; } bool being_analyzed: 1; bool been_analyzed: 1; // These bits are set of this node has to know what the preceding // character was. bool follows_word_interest: 1; bool follows_newline_interest: 1; bool follows_start_interest: 1; bool at_end: 1; bool visited: 1; bool replacement_calculated: 1; }; // Details of a quick mask-compare check that can look ahead in the // input stream. class QuickCheckDetails { public: QuickCheckDetails() : characters_(0), mask_(0), value_(0), cannot_match_(false) {} explicit QuickCheckDetails(int characters) : characters_(characters), mask_(0), value_(0), cannot_match_(false) {} bool Rationalize(bool ascii); // Merge in the information from another branch of an alternation. void Merge(QuickCheckDetails* other, int from_index); // Advance the current position by some amount. void Advance(int by, bool ascii); void Clear(); bool cannot_match() { return cannot_match_; } void set_cannot_match() { cannot_match_ = true; } int characters() { return characters_; } void set_characters(int characters) { characters_ = characters; } struct Position { Position() : mask(0), value(0), determines_perfectly(false) { } char16_t mask; char16_t value; bool determines_perfectly; }; Position* positions(int index) { MOZ_ASSERT(index >= 0); MOZ_ASSERT(index < characters_); return positions_ + index; } uint32_t mask() { return mask_; } uint32_t value() { return value_; } private: // How many characters do we have quick check information from. This is // the same for all branches of a choice node. int characters_; Position positions_[4]; // These values are the condensate of the above array after Rationalize(). uint32_t mask_; uint32_t value_; // If set to true, there is no way this quick check can match at all. // E.g., if it requires to be at the start of the input, and isn't. bool cannot_match_; }; class RegExpNode { public: explicit RegExpNode(LifoAlloc* alloc); virtual ~RegExpNode() {} virtual void Accept(NodeVisitor* visitor) = 0; // Generates a goto to this node or actually generates the code at this point. virtual void Emit(RegExpCompiler* compiler, Trace* trace) = 0; // How many characters must this node consume at a minimum in order to // succeed. If we have found at least 'still_to_find' characters that // must be consumed there is no need to ask any following nodes whether // they are sure to eat any more characters. The not_at_start argument is // used to indicate that we know we are not at the start of the input. In // this case anchored branches will always fail and can be ignored when // determining how many characters are consumed on success. virtual int EatsAtLeast(int still_to_find, int budget, bool not_at_start) = 0; // Emits some quick code that checks whether the preloaded characters match. // Falls through on certain failure, jumps to the label on possible success. // If the node cannot make a quick check it does nothing and returns false. bool EmitQuickCheck(RegExpCompiler* compiler, Trace* trace, bool preload_has_checked_bounds, jit::Label* on_possible_success, QuickCheckDetails* details_return, bool fall_through_on_failure); // For a given number of characters this returns a mask and a value. The // next n characters are anded with the mask and compared with the value. // A comparison failure indicates the node cannot match the next n characters. // A comparison success indicates the node may match. virtual void GetQuickCheckDetails(QuickCheckDetails* details, RegExpCompiler* compiler, int characters_filled_in, bool not_at_start) = 0; static const int kNodeIsTooComplexForGreedyLoops = -1; virtual int GreedyLoopTextLength() { return kNodeIsTooComplexForGreedyLoops; } // Only returns the successor for a text node of length 1 that matches any // character and that has no guards on it. virtual RegExpNode* GetSuccessorOfOmnivorousTextNode(RegExpCompiler* compiler) { return nullptr; } static const int kRecursionBudget = 200; // Collects information on the possible code units (mod 128) that can match if // we look forward. This is used for a Boyer-Moore-like string searching // implementation. TODO(erikcorry): This should share more code with // EatsAtLeast, GetQuickCheckDetails. The budget argument is used to limit // the number of nodes we are willing to look at in order to create this data. virtual bool FillInBMInfo(int offset, int budget, BoyerMooreLookahead* bm, bool not_at_start) { MOZ_CRASH("Bad call"); } // If we know that the input is ASCII then there are some nodes that can // never match. This method returns a node that can be substituted for // itself, or nullptr if the node can never match. virtual RegExpNode* FilterASCII(int depth, bool ignore_case, bool unicode) { return this; } // Helper for FilterASCII. RegExpNode* replacement() { MOZ_ASSERT(info()->replacement_calculated); return replacement_; } RegExpNode* set_replacement(RegExpNode* replacement) { info()->replacement_calculated = true; replacement_ = replacement; return replacement; // For convenience. } // We want to avoid recalculating the lookahead info, so we store it on the // node. Only info that is for this node is stored. We can tell that the // info is for this node when offset == 0, so the information is calculated // relative to this node. void SaveBMInfo(BoyerMooreLookahead* bm, bool not_at_start, int offset) { if (offset == 0) set_bm_info(not_at_start, bm); } jit::Label* label() { return &label_; } // If non-generic code is generated for a node (i.e. the node is not at the // start of the trace) then it cannot be reused. This variable sets a limit // on how often we allow that to happen before we insist on starting a new // trace and generating generic code for a node that can be reused by flushing // the deferred actions in the current trace and generating a goto. static const int kMaxCopiesCodeGenerated = 10; NodeInfo* info() { return &info_; } BoyerMooreLookahead* bm_info(bool not_at_start) { return bm_info_[not_at_start ? 1 : 0]; } LifoAlloc* alloc() const { return alloc_; } protected: enum LimitResult { DONE, CONTINUE }; RegExpNode* replacement_; LimitResult LimitVersions(RegExpCompiler* compiler, Trace* trace); void set_bm_info(bool not_at_start, BoyerMooreLookahead* bm) { bm_info_[not_at_start ? 1 : 0] = bm; } private: static const int kFirstCharBudget = 10; jit::Label label_; NodeInfo info_; // This variable keeps track of how many times code has been generated for // this node (in different traces). We don't keep track of where the // generated code is located unless the code is generated at the start of // a trace, in which case it is generic and can be reused by flushing the // deferred operations in the current trace and generating a goto. int trace_count_; BoyerMooreLookahead* bm_info_[2]; LifoAlloc* alloc_; }; // A simple closed interval. class Interval { public: Interval() : from_(kNone), to_(kNone) { } Interval(int from, int to) : from_(from), to_(to) { } Interval Union(Interval that) { if (that.from_ == kNone) return *this; else if (from_ == kNone) return that; else return Interval(Min(from_, that.from_), Max(to_, that.to_)); } bool Contains(int value) { return (from_ <= value) && (value <= to_); } bool is_empty() { return from_ == kNone; } int from() const { return from_; } int to() const { return to_; } static Interval Empty() { return Interval(); } static const int kNone = -1; private: int from_; int to_; }; class SeqRegExpNode : public RegExpNode { public: explicit SeqRegExpNode(RegExpNode* on_success) : RegExpNode(on_success->alloc()), on_success_(on_success) {} RegExpNode* on_success() { return on_success_; } void set_on_success(RegExpNode* node) { on_success_ = node; } virtual RegExpNode* FilterASCII(int depth, bool ignore_case, bool unicode); virtual bool FillInBMInfo(int offset, int budget, BoyerMooreLookahead* bm, bool not_at_start); protected: RegExpNode* FilterSuccessor(int depth, bool ignore_case, bool unicode); private: RegExpNode* on_success_; }; class ActionNode : public SeqRegExpNode { public: enum ActionType { SET_REGISTER, INCREMENT_REGISTER, STORE_POSITION, BEGIN_SUBMATCH, POSITIVE_SUBMATCH_SUCCESS, EMPTY_MATCH_CHECK, CLEAR_CAPTURES }; ActionNode(ActionType action_type, RegExpNode* on_success) : SeqRegExpNode(on_success), action_type_(action_type) {} static ActionNode* SetRegister(int reg, int val, RegExpNode* on_success); static ActionNode* IncrementRegister(int reg, RegExpNode* on_success); static ActionNode* StorePosition(int reg, bool is_capture, RegExpNode* on_success); static ActionNode* ClearCaptures(Interval range, RegExpNode* on_success); static ActionNode* BeginSubmatch(int stack_pointer_reg, int position_reg, RegExpNode* on_success); static ActionNode* PositiveSubmatchSuccess(int stack_pointer_reg, int restore_reg, int clear_capture_count, int clear_capture_from, RegExpNode* on_success); static ActionNode* EmptyMatchCheck(int start_register, int repetition_register, int repetition_limit, RegExpNode* on_success); virtual void Accept(NodeVisitor* visitor); virtual void Emit(RegExpCompiler* compiler, Trace* trace); virtual int EatsAtLeast(int still_to_find, int budget, bool not_at_start); virtual void GetQuickCheckDetails(QuickCheckDetails* details, RegExpCompiler* compiler, int filled_in, bool not_at_start) { return on_success()->GetQuickCheckDetails( details, compiler, filled_in, not_at_start); } virtual bool FillInBMInfo(int offset, int budget, BoyerMooreLookahead* bm, bool not_at_start); ActionType action_type() { return action_type_; } // TODO(erikcorry): We should allow some action nodes in greedy loops. virtual int GreedyLoopTextLength() { return kNodeIsTooComplexForGreedyLoops; } private: union { struct { int reg; int value; } u_store_register; struct { int reg; } u_increment_register; struct { int reg; bool is_capture; } u_position_register; struct { int stack_pointer_register; int current_position_register; int clear_register_count; int clear_register_from; } u_submatch; struct { int start_register; int repetition_register; int repetition_limit; } u_empty_match_check; struct { int range_from; int range_to; } u_clear_captures; } data_; ActionType action_type_; friend class DotPrinter; }; class TextNode : public SeqRegExpNode { public: TextNode(TextElementVector* elements, RegExpNode* on_success) : SeqRegExpNode(on_success), elements_(elements) {} TextNode(RegExpCharacterClass* that, RegExpNode* on_success) : SeqRegExpNode(on_success), elements_(alloc()->newInfallible<TextElementVector>(*alloc())) { elements_->append(TextElement::CharClass(that)); } virtual void Accept(NodeVisitor* visitor); virtual void Emit(RegExpCompiler* compiler, Trace* trace); virtual int EatsAtLeast(int still_to_find, int budget, bool not_at_start); virtual void GetQuickCheckDetails(QuickCheckDetails* details, RegExpCompiler* compiler, int characters_filled_in, bool not_at_start); TextElementVector& elements() { return *elements_; } void MakeCaseIndependent(bool is_ascii, bool unicode); virtual int GreedyLoopTextLength(); virtual RegExpNode* GetSuccessorOfOmnivorousTextNode( RegExpCompiler* compiler); virtual bool FillInBMInfo(int offset, int budget, BoyerMooreLookahead* bm, bool not_at_start); void CalculateOffsets(); virtual RegExpNode* FilterASCII(int depth, bool ignore_case, bool unicode); private: enum TextEmitPassType { NON_ASCII_MATCH, // Check for characters that can't match. SIMPLE_CHARACTER_MATCH, // Case-dependent single character check. NON_LETTER_CHARACTER_MATCH, // Check characters that have no case equivs. CASE_CHARACTER_MATCH, // Case-independent single character check. CHARACTER_CLASS_MATCH // Character class. }; static bool SkipPass(int pass, bool ignore_case); static const int kFirstRealPass = SIMPLE_CHARACTER_MATCH; static const int kLastPass = CHARACTER_CLASS_MATCH; void TextEmitPass(RegExpCompiler* compiler, TextEmitPassType pass, bool preloaded, Trace* trace, bool first_element_checked, int* checked_up_to); int Length(); TextElementVector* elements_; }; class AssertionNode : public SeqRegExpNode { public: enum AssertionType { AT_END, AT_START, AT_BOUNDARY, AT_NON_BOUNDARY, AFTER_NEWLINE, NOT_AFTER_LEAD_SURROGATE, NOT_IN_SURROGATE_PAIR }; AssertionNode(AssertionType t, RegExpNode* on_success) : SeqRegExpNode(on_success), assertion_type_(t) {} static AssertionNode* AtEnd(RegExpNode* on_success) { return on_success->alloc()->newInfallible<AssertionNode>(AT_END, on_success); } static AssertionNode* AtStart(RegExpNode* on_success) { return on_success->alloc()->newInfallible<AssertionNode>(AT_START, on_success); } static AssertionNode* AtBoundary(RegExpNode* on_success) { return on_success->alloc()->newInfallible<AssertionNode>(AT_BOUNDARY, on_success); } static AssertionNode* AtNonBoundary(RegExpNode* on_success) { return on_success->alloc()->newInfallible<AssertionNode>(AT_NON_BOUNDARY, on_success); } static AssertionNode* AfterNewline(RegExpNode* on_success) { return on_success->alloc()->newInfallible<AssertionNode>(AFTER_NEWLINE, on_success); } static AssertionNode* NotAfterLeadSurrogate(RegExpNode* on_success) { return on_success->alloc()->newInfallible<AssertionNode>(NOT_AFTER_LEAD_SURROGATE, on_success); } static AssertionNode* NotInSurrogatePair(RegExpNode* on_success) { return on_success->alloc()->newInfallible<AssertionNode>(NOT_IN_SURROGATE_PAIR, on_success); } virtual void Accept(NodeVisitor* visitor); virtual void Emit(RegExpCompiler* compiler, Trace* trace); virtual int EatsAtLeast(int still_to_find, int budget, bool not_at_start); virtual void GetQuickCheckDetails(QuickCheckDetails* details, RegExpCompiler* compiler, int filled_in, bool not_at_start); virtual bool FillInBMInfo(int offset, int budget, BoyerMooreLookahead* bm, bool not_at_start); AssertionType assertion_type() { return assertion_type_; } private: void EmitBoundaryCheck(RegExpCompiler* compiler, Trace* trace); enum IfPrevious { kIsNonWord, kIsWord }; void BacktrackIfPrevious(RegExpCompiler* compiler, Trace* trace, IfPrevious backtrack_if_previous); AssertionType assertion_type_; }; class BackReferenceNode : public SeqRegExpNode { public: BackReferenceNode(int start_reg, int end_reg, RegExpNode* on_success) : SeqRegExpNode(on_success), start_reg_(start_reg), end_reg_(end_reg) {} virtual void Accept(NodeVisitor* visitor); int start_register() { return start_reg_; } int end_register() { return end_reg_; } virtual void Emit(RegExpCompiler* compiler, Trace* trace); virtual int EatsAtLeast(int still_to_find, int recursion_depth, bool not_at_start); virtual void GetQuickCheckDetails(QuickCheckDetails* details, RegExpCompiler* compiler, int characters_filled_in, bool not_at_start) { return; } virtual bool FillInBMInfo(int offset, int budget, BoyerMooreLookahead* bm, bool not_at_start); private: int start_reg_; int end_reg_; }; class EndNode : public RegExpNode { public: enum Action { ACCEPT, BACKTRACK, NEGATIVE_SUBMATCH_SUCCESS }; explicit EndNode(LifoAlloc* alloc, Action action) : RegExpNode(alloc), action_(action) {} virtual void Accept(NodeVisitor* visitor); virtual void Emit(RegExpCompiler* compiler, Trace* trace); virtual int EatsAtLeast(int still_to_find, int recursion_depth, bool not_at_start) { return 0; } virtual void GetQuickCheckDetails(QuickCheckDetails* details, RegExpCompiler* compiler, int characters_filled_in, bool not_at_start) { // Returning 0 from EatsAtLeast should ensure we never get here. MOZ_CRASH("Bad call"); } virtual bool FillInBMInfo(int offset, int budget, BoyerMooreLookahead* bm, bool not_at_start) { // Returning 0 from EatsAtLeast should ensure we never get here. MOZ_CRASH("Bad call"); } private: Action action_; }; class NegativeSubmatchSuccess : public EndNode { public: NegativeSubmatchSuccess(LifoAlloc* alloc, int stack_pointer_reg, int position_reg, int clear_capture_count, int clear_capture_start) : EndNode(alloc, NEGATIVE_SUBMATCH_SUCCESS), stack_pointer_register_(stack_pointer_reg), current_position_register_(position_reg), clear_capture_count_(clear_capture_count), clear_capture_start_(clear_capture_start) {} virtual void Emit(RegExpCompiler* compiler, Trace* trace); private: int stack_pointer_register_; int current_position_register_; int clear_capture_count_; int clear_capture_start_; }; class Guard { public: enum Relation { LT, GEQ }; Guard(int reg, Relation op, int value) : reg_(reg), op_(op), value_(value) {} int reg() { return reg_; } Relation op() { return op_; } int value() { return value_; } private: int reg_; Relation op_; int value_; }; typedef InfallibleVector<Guard*, 1> GuardVector; class GuardedAlternative { public: explicit GuardedAlternative(RegExpNode* node) : node_(node), guards_(nullptr) {} void AddGuard(LifoAlloc* alloc, Guard* guard); RegExpNode* node() const { return node_; } void set_node(RegExpNode* node) { node_ = node; } const GuardVector* guards() const { return guards_; } private: RegExpNode* node_; GuardVector* guards_; }; typedef InfallibleVector<GuardedAlternative, 0> GuardedAlternativeVector; class AlternativeGeneration; class ChoiceNode : public RegExpNode { public: explicit ChoiceNode(LifoAlloc* alloc, int expected_size) : RegExpNode(alloc), alternatives_(*alloc), table_(nullptr), not_at_start_(false), being_calculated_(false) { alternatives_.reserve(expected_size); } virtual void Accept(NodeVisitor* visitor); void AddAlternative(GuardedAlternative node) { alternatives_.append(node); } GuardedAlternativeVector& alternatives() { return alternatives_; } DispatchTable* GetTable(bool ignore_case); virtual void Emit(RegExpCompiler* compiler, Trace* trace); virtual int EatsAtLeast(int still_to_find, int budget, bool not_at_start); int EatsAtLeastHelper(int still_to_find, int budget, RegExpNode* ignore_this_node, bool not_at_start); virtual void GetQuickCheckDetails(QuickCheckDetails* details, RegExpCompiler* compiler, int characters_filled_in, bool not_at_start); virtual bool FillInBMInfo(int offset, int budget, BoyerMooreLookahead* bm, bool not_at_start); bool being_calculated() { return being_calculated_; } bool not_at_start() { return not_at_start_; } void set_not_at_start() { not_at_start_ = true; } void set_being_calculated(bool b) { being_calculated_ = b; } virtual bool try_to_emit_quick_check_for_alternative(int i) { return true; } virtual RegExpNode* FilterASCII(int depth, bool ignore_case, bool unicode); protected: int GreedyLoopTextLengthForAlternative(GuardedAlternative* alternative); GuardedAlternativeVector alternatives_; private: friend class Analysis; void GenerateGuard(RegExpMacroAssembler* macro_assembler, Guard* guard, Trace* trace); int CalculatePreloadCharacters(RegExpCompiler* compiler, int eats_at_least); void EmitOutOfLineContinuation(RegExpCompiler* compiler, Trace* trace, GuardedAlternative alternative, AlternativeGeneration* alt_gen, int preload_characters, bool next_expects_preload); DispatchTable* table_; // If true, this node is never checked at the start of the input. // Allows a new trace to start with at_start() set to false. bool not_at_start_; bool being_calculated_; }; class NegativeLookaheadChoiceNode : public ChoiceNode { public: explicit NegativeLookaheadChoiceNode(LifoAlloc* alloc, GuardedAlternative this_must_fail, GuardedAlternative then_do_this) : ChoiceNode(alloc, 2) { AddAlternative(this_must_fail); AddAlternative(then_do_this); } virtual int EatsAtLeast(int still_to_find, int budget, bool not_at_start); virtual void GetQuickCheckDetails(QuickCheckDetails* details, RegExpCompiler* compiler, int characters_filled_in, bool not_at_start); virtual bool FillInBMInfo(int offset, int budget, BoyerMooreLookahead* bm, bool not_at_start); // For a negative lookahead we don't emit the quick check for the // alternative that is expected to fail. This is because quick check code // starts by loading enough characters for the alternative that takes fewest // characters, but on a negative lookahead the negative branch did not take // part in that calculation (EatsAtLeast) so the assumptions don't hold. virtual bool try_to_emit_quick_check_for_alternative(int i) { return i != 0; } virtual RegExpNode* FilterASCII(int depth, bool ignore_case, bool unicode); }; class LoopChoiceNode : public ChoiceNode { public: explicit LoopChoiceNode(LifoAlloc* alloc, bool body_can_be_zero_length) : ChoiceNode(alloc, 2), loop_node_(nullptr), continue_node_(nullptr), body_can_be_zero_length_(body_can_be_zero_length) {} void AddLoopAlternative(GuardedAlternative alt); void AddContinueAlternative(GuardedAlternative alt); virtual void Emit(RegExpCompiler* compiler, Trace* trace); virtual int EatsAtLeast(int still_to_find, int budget, bool not_at_start); virtual void GetQuickCheckDetails(QuickCheckDetails* details, RegExpCompiler* compiler, int characters_filled_in, bool not_at_start); virtual bool FillInBMInfo(int offset, int budget, BoyerMooreLookahead* bm, bool not_at_start); RegExpNode* loop_node() { return loop_node_; } RegExpNode* continue_node() { return continue_node_; } bool body_can_be_zero_length() { return body_can_be_zero_length_; } virtual void Accept(NodeVisitor* visitor); virtual RegExpNode* FilterASCII(int depth, bool ignore_case, bool unicode); private: // AddAlternative is made private for loop nodes because alternatives // should not be added freely, we need to keep track of which node // goes back to the node itself. void AddAlternative(GuardedAlternative node) { ChoiceNode::AddAlternative(node); } RegExpNode* loop_node_; RegExpNode* continue_node_; bool body_can_be_zero_length_; }; // Improve the speed that we scan for an initial point where a non-anchored // regexp can match by using a Boyer-Moore-like table. This is done by // identifying non-greedy non-capturing loops in the nodes that eat any // character one at a time. For example in the middle of the regexp // /foo[\s\S]*?bar/ we find such a loop. There is also such a loop implicitly // inserted at the start of any non-anchored regexp. // // When we have found such a loop we look ahead in the nodes to find the set of // characters that can come at given distances. For example for the regexp // /.?foo/ we know that there are at least 3 characters ahead of us, and the // sets of characters that can occur are [any, [f, o], [o]]. We find a range in // the lookahead info where the set of characters is reasonably constrained. In // our example this is from index 1 to 2 (0 is not constrained). We can now // look 3 characters ahead and if we don't find one of [f, o] (the union of // [f, o] and [o]) then we can skip forwards by the range size (in this case 2). // // For Unicode input strings we do the same, but modulo 128. // // We also look at the first string fed to the regexp and use that to get a hint // of the character frequencies in the inputs. This affects the assessment of // whether the set of characters is 'reasonably constrained'. // // We also have another lookahead mechanism (called quick check in the code), // which uses a wide load of multiple characters followed by a mask and compare // to determine whether a match is possible at this point. enum ContainedInLattice { kNotYet = 0, kLatticeIn = 1, kLatticeOut = 2, kLatticeUnknown = 3 // Can also mean both in and out. }; inline ContainedInLattice Combine(ContainedInLattice a, ContainedInLattice b) { return static_cast<ContainedInLattice>(a | b); } ContainedInLattice AddRange(ContainedInLattice a, const int* ranges, int ranges_size, Interval new_range); class BoyerMoorePositionInfo { public: explicit BoyerMoorePositionInfo(LifoAlloc* alloc, bool unicode_ignore_case) : map_(*alloc), map_count_(0), w_(kNotYet), s_(kNotYet), d_(kNotYet), surrogate_(kNotYet), unicode_ignore_case_(unicode_ignore_case) { map_.reserve(kMapSize); for (int i = 0; i < kMapSize; i++) map_.append(false); } bool& at(int i) { return map_[i]; } static const int kMapSize = 128; static const int kMask = kMapSize - 1; int map_count() const { return map_count_; } void Set(int character); void SetInterval(const Interval& interval); void SetAll(); bool is_non_word() { return w_ == kLatticeOut; } bool is_word() { return w_ == kLatticeIn; } private: InfallibleVector<bool, 0> map_; int map_count_; // Number of set bits in the map. ContainedInLattice w_; // The \w character class. ContainedInLattice s_; // The \s character class. ContainedInLattice d_; // The \d character class. ContainedInLattice surrogate_; // Surrogate UTF-16 code units. // True if the RegExp has unicode and ignoreCase flags. bool unicode_ignore_case_; }; typedef InfallibleVector<BoyerMoorePositionInfo*, 1> BoyerMoorePositionInfoVector; class BoyerMooreLookahead { public: BoyerMooreLookahead(LifoAlloc* alloc, size_t length, RegExpCompiler* compiler); int length() { return length_; } int max_char() { return max_char_; } RegExpCompiler* compiler() { return compiler_; } int Count(int map_number) { return bitmaps_[map_number]->map_count(); } BoyerMoorePositionInfo* at(int i) { return bitmaps_[i]; } void Set(int map_number, int character) { if (character > max_char_) return; BoyerMoorePositionInfo* info = bitmaps_[map_number]; info->Set(character); } void SetInterval(int map_number, const Interval& interval) { if (interval.from() > max_char_) return; BoyerMoorePositionInfo* info = bitmaps_[map_number]; if (interval.to() > max_char_) { info->SetInterval(Interval(interval.from(), max_char_)); } else { info->SetInterval(interval); } } void SetAll(int map_number) { bitmaps_[map_number]->SetAll(); } void SetRest(int from_map) { for (int i = from_map; i < length_; i++) SetAll(i); } bool EmitSkipInstructions(RegExpMacroAssembler* masm); bool CheckOverRecursed(); private: // This is the value obtained by EatsAtLeast. If we do not have at least this // many characters left in the sample string then the match is bound to fail. // Therefore it is OK to read a character this far ahead of the current match // point. int length_; RegExpCompiler* compiler_; // 0x7f for ASCII, 0xffff for UTF-16. int max_char_; BoyerMoorePositionInfoVector bitmaps_; int GetSkipTable(int min_lookahead, int max_lookahead, uint8_t* boolean_skip_table); bool FindWorthwhileInterval(int* from, int* to); int FindBestInterval(int max_number_of_chars, int old_biggest_points, int* from, int* to); }; // There are many ways to generate code for a node. This class encapsulates // the current way we should be generating. In other words it encapsulates // the current state of the code generator. The effect of this is that we // generate code for paths that the matcher can take through the regular // expression. A given node in the regexp can be code-generated several times // as it can be part of several traces. For example for the regexp: // /foo(bar|ip)baz/ the code to match baz will be generated twice, once as part // of the foo-bar-baz trace and once as part of the foo-ip-baz trace. The code // to match foo is generated only once (the traces have a common prefix). The // code to store the capture is deferred and generated (twice) after the places // where baz has been matched. class Trace { public: // A value for a property that is either known to be true, know to be false, // or not known. enum TriBool { UNKNOWN = -1, FALSE_VALUE = 0, TRUE_VALUE = 1 }; class DeferredAction { public: DeferredAction(ActionNode::ActionType action_type, int reg) : action_type_(action_type), reg_(reg), next_(nullptr) {} DeferredAction* next() { return next_; } bool Mentions(int reg); int reg() { return reg_; } ActionNode::ActionType action_type() { return action_type_; } private: ActionNode::ActionType action_type_; int reg_; DeferredAction* next_; friend class Trace; }; class DeferredCapture : public DeferredAction { public: DeferredCapture(int reg, bool is_capture, Trace* trace) : DeferredAction(ActionNode::STORE_POSITION, reg), cp_offset_(trace->cp_offset()), is_capture_(is_capture) {} int cp_offset() { return cp_offset_; } bool is_capture() { return is_capture_; } private: int cp_offset_; bool is_capture_; void set_cp_offset(int cp_offset) { cp_offset_ = cp_offset; } }; class DeferredSetRegister : public DeferredAction { public: DeferredSetRegister(int reg, int value) : DeferredAction(ActionNode::SET_REGISTER, reg), value_(value) {} int value() { return value_; } private: int value_; }; class DeferredClearCaptures : public DeferredAction { public: explicit DeferredClearCaptures(Interval range) : DeferredAction(ActionNode::CLEAR_CAPTURES, -1), range_(range) {} Interval range() { return range_; } private: Interval range_; }; class DeferredIncrementRegister : public DeferredAction { public: explicit DeferredIncrementRegister(int reg) : DeferredAction(ActionNode::INCREMENT_REGISTER, reg) {} }; Trace() : cp_offset_(0), actions_(nullptr), backtrack_(nullptr), stop_node_(nullptr), loop_label_(nullptr), characters_preloaded_(0), bound_checked_up_to_(0), flush_budget_(100), at_start_(UNKNOWN) {} // End the trace. This involves flushing the deferred actions in the trace // and pushing a backtrack location onto the backtrack stack. Once this is // done we can start a new trace or go to one that has already been // generated. void Flush(RegExpCompiler* compiler, RegExpNode* successor); int cp_offset() { return cp_offset_; } DeferredAction* actions() { return actions_; } // A trivial trace is one that has no deferred actions or other state that // affects the assumptions used when generating code. There is no recorded // backtrack location in a trivial trace, so with a trivial trace we will // generate code that, on a failure to match, gets the backtrack location // from the backtrack stack rather than using a direct jump instruction. We // always start code generation with a trivial trace and non-trivial traces // are created as we emit code for nodes or add to the list of deferred // actions in the trace. The location of the code generated for a node using // a trivial trace is recorded in a label in the node so that gotos can be // generated to that code. bool is_trivial() { return backtrack_ == nullptr && actions_ == nullptr && cp_offset_ == 0 && characters_preloaded_ == 0 && bound_checked_up_to_ == 0 && quick_check_performed_.characters() == 0 && at_start_ == UNKNOWN; } TriBool at_start() { return at_start_; } void set_at_start(bool at_start) { at_start_ = at_start ? TRUE_VALUE : FALSE_VALUE; } jit::Label* backtrack() { return backtrack_; } jit::Label* loop_label() { return loop_label_; } RegExpNode* stop_node() { return stop_node_; } int characters_preloaded() { return characters_preloaded_; } int bound_checked_up_to() { return bound_checked_up_to_; } int flush_budget() { return flush_budget_; } QuickCheckDetails* quick_check_performed() { return &quick_check_performed_; } bool mentions_reg(int reg); // Returns true if a deferred position store exists to the specified // register and stores the offset in the out-parameter. Otherwise // returns false. bool GetStoredPosition(int reg, int* cp_offset); // These set methods and AdvanceCurrentPositionInTrace should be used only on // new traces - the intention is that traces are immutable after creation. void add_action(DeferredAction* new_action) { MOZ_ASSERT(new_action->next_ == nullptr); new_action->next_ = actions_; actions_ = new_action; } void set_backtrack(jit::Label* backtrack) { backtrack_ = backtrack; } void set_stop_node(RegExpNode* node) { stop_node_ = node; } void set_loop_label(jit::Label* label) { loop_label_ = label; } void set_characters_preloaded(int count) { characters_preloaded_ = count; } void set_bound_checked_up_to(int to) { bound_checked_up_to_ = to; } void set_flush_budget(int to) { flush_budget_ = to; } void set_quick_check_performed(QuickCheckDetails* d) { quick_check_performed_ = *d; } void InvalidateCurrentCharacter(); void AdvanceCurrentPositionInTrace(int by, RegExpCompiler* compiler); private: int FindAffectedRegisters(LifoAlloc* alloc, OutSet* affected_registers); void PerformDeferredActions(LifoAlloc* alloc, RegExpMacroAssembler* macro, int max_register, OutSet& affected_registers, OutSet* registers_to_pop, OutSet* registers_to_clear); void RestoreAffectedRegisters(RegExpMacroAssembler* macro, int max_register, OutSet& registers_to_pop, OutSet& registers_to_clear); int cp_offset_; DeferredAction* actions_; jit::Label* backtrack_; RegExpNode* stop_node_; jit::Label* loop_label_; int characters_preloaded_; int bound_checked_up_to_; QuickCheckDetails quick_check_performed_; int flush_budget_; TriBool at_start_; }; class NodeVisitor { public: virtual ~NodeVisitor() { } #define DECLARE_VISIT(Type) \ virtual void Visit##Type(Type##Node* that) = 0; FOR_EACH_NODE_TYPE(DECLARE_VISIT) #undef DECLARE_VISIT virtual void VisitLoopChoice(LoopChoiceNode* that) { VisitChoice(that); } }; // Assertion propagation moves information about assertions such as // \b to the affected nodes. For instance, in /.\b./ information must // be propagated to the first '.' that whatever follows needs to know // if it matched a word or a non-word, and to the second '.' that it // has to check if it succeeds a word or non-word. In this case the // result will be something like: // // +-------+ +------------+ // | . | | . | // +-------+ ---> +------------+ // | word? | | check word | // +-------+ +------------+ class Analysis : public NodeVisitor { public: Analysis(JSContext* cx, bool ignore_case, bool is_ascii, bool unicode) : cx(cx), ignore_case_(ignore_case), is_ascii_(is_ascii), unicode_(unicode), error_message_(nullptr) {} void EnsureAnalyzed(RegExpNode* node); #define DECLARE_VISIT(Type) \ virtual void Visit##Type(Type##Node* that); FOR_EACH_NODE_TYPE(DECLARE_VISIT) #undef DECLARE_VISIT virtual void VisitLoopChoice(LoopChoiceNode* that); bool has_failed() { return error_message_ != nullptr; } const char* errorMessage() { MOZ_ASSERT(error_message_ != nullptr); return error_message_; } void failASCII(const char* error_message) { error_message_ = error_message; } private: JSContext* cx; bool ignore_case_; bool is_ascii_; bool unicode_; const char* error_message_; Analysis(Analysis&) = delete; void operator=(Analysis&) = delete; }; } } // namespace js::irregexp #endif // V8_JSREGEXP_H_