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// Copyright 2019 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef V8_REGEXP_REGEXP_NODES_H_
#define V8_REGEXP_REGEXP_NODES_H_
#include "src/regexp/regexp-macro-assembler.h"
#include "src/zone/zone.h"
namespace v8 {
namespace internal {
class AlternativeGenerationList;
class BoyerMooreLookahead;
class GreedyLoopState;
class Label;
class NodeVisitor;
class QuickCheckDetails;
class RegExpCompiler;
class Trace;
struct PreloadState;
class ChoiceNode;
#define FOR_EACH_NODE_TYPE(VISIT) \
VISIT(End) \
VISIT(Action) \
VISIT(Choice) \
VISIT(LoopChoice) \
VISIT(NegativeLookaroundChoice) \
VISIT(BackReference) \
VISIT(Assertion) \
VISIT(Text)
struct NodeInfo final {
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;
};
struct EatsAtLeastInfo final {
EatsAtLeastInfo() : EatsAtLeastInfo(0) {}
explicit EatsAtLeastInfo(uint8_t eats)
: eats_at_least_from_possibly_start(eats),
eats_at_least_from_not_start(eats) {}
void SetMin(const EatsAtLeastInfo& other) {
if (other.eats_at_least_from_possibly_start <
eats_at_least_from_possibly_start) {
eats_at_least_from_possibly_start =
other.eats_at_least_from_possibly_start;
}
if (other.eats_at_least_from_not_start < eats_at_least_from_not_start) {
eats_at_least_from_not_start = other.eats_at_least_from_not_start;
}
}
// Any successful match starting from the current node will consume at least
// this many characters. This does not necessarily mean that there is a
// possible match with exactly this many characters, but we generally try to
// get this number as high as possible to allow for early exit on failure.
uint8_t eats_at_least_from_possibly_start;
// Like eats_at_least_from_possibly_start, but with the additional assumption
// that start-of-string assertions (^) can't match. This value is greater than
// or equal to eats_at_least_from_possibly_start.
uint8_t eats_at_least_from_not_start;
};
class RegExpNode : public ZoneObject {
public:
explicit RegExpNode(Zone* zone)
: replacement_(nullptr),
on_work_list_(false),
trace_count_(0),
zone_(zone) {
bm_info_[0] = bm_info_[1] = nullptr;
}
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. 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. If this node has not been analyzed yet, EatsAtLeast returns 0.
int EatsAtLeast(bool not_at_start);
// Returns how many characters this node must consume in order to succeed,
// given that this is a LoopChoiceNode whose counter register is in a
// newly-initialized state at the current position in the generated code. For
// example, consider /a{6,8}/. Absent any extra information, the
// LoopChoiceNode for the repetition must report that it consumes at least
// zero characters, because it may have already looped several times. However,
// with a newly-initialized counter, it can report that it consumes at least
// six characters.
virtual EatsAtLeastInfo EatsAtLeastFromLoopEntry();
// 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* bounds_check_trace,
Trace* trace, bool preload_has_checked_bounds,
Label* on_possible_success,
QuickCheckDetails* details_return,
bool fall_through_on_failure, ChoiceNode* predecessor);
// 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;
// Fills in quick check details for this node, given that this is a
// LoopChoiceNode whose counter register is in a newly-initialized state at
// the current position in the generated code. For example, consider /a{6,8}/.
// Absent any extra information, the LoopChoiceNode for the repetition cannot
// generate any useful quick check because a match might be the (empty)
// continuation node. However, with a newly-initialized counter, it can
// generate a quick check for several 'a' characters at once.
virtual void GetQuickCheckDetailsFromLoopEntry(QuickCheckDetails* details,
RegExpCompiler* compiler,
int characters_filled_in,
bool not_at_start);
static const int kNodeIsTooComplexForGreedyLoops = kMinInt;
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;
}
// 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.
static const int kRecursionBudget = 200;
bool KeepRecursing(RegExpCompiler* compiler);
virtual void FillInBMInfo(Isolate* isolate, int offset, int budget,
BoyerMooreLookahead* bm, bool not_at_start) {
UNREACHABLE();
}
// If we know that the input is one-byte 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* FilterOneByte(int depth) { return this; }
// Helper for FilterOneByte.
RegExpNode* replacement() {
DCHECK(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);
}
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;
bool on_work_list() { return on_work_list_; }
void set_on_work_list(bool value) { on_work_list_ = value; }
NodeInfo* info() { return &info_; }
const EatsAtLeastInfo* eats_at_least_info() const { return &eats_at_least_; }
void set_eats_at_least_info(const EatsAtLeastInfo& eats_at_least) {
eats_at_least_ = eats_at_least;
}
BoyerMooreLookahead* bm_info(bool not_at_start) {
return bm_info_[not_at_start ? 1 : 0];
}
Zone* zone() const { return zone_; }
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;
Label label_;
bool on_work_list_;
NodeInfo info_;
// Saved values for EatsAtLeast results, to avoid recomputation. Filled in
// during analysis (valid if info_.been_analyzed is true).
EatsAtLeastInfo eats_at_least_;
// 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];
Zone* zone_;
};
class SeqRegExpNode : public RegExpNode {
public:
explicit SeqRegExpNode(RegExpNode* on_success)
: RegExpNode(on_success->zone()), on_success_(on_success) {}
RegExpNode* on_success() { return on_success_; }
void set_on_success(RegExpNode* node) { on_success_ = node; }
RegExpNode* FilterOneByte(int depth) override;
void FillInBMInfo(Isolate* isolate, int offset, int budget,
BoyerMooreLookahead* bm, bool not_at_start) override {
on_success_->FillInBMInfo(isolate, offset, budget - 1, bm, not_at_start);
if (offset == 0) set_bm_info(not_at_start, bm);
}
protected:
RegExpNode* FilterSuccessor(int depth);
private:
RegExpNode* on_success_;
};
class ActionNode : public SeqRegExpNode {
public:
enum ActionType {
SET_REGISTER_FOR_LOOP,
INCREMENT_REGISTER,
STORE_POSITION,
BEGIN_SUBMATCH,
POSITIVE_SUBMATCH_SUCCESS,
EMPTY_MATCH_CHECK,
CLEAR_CAPTURES
};
static ActionNode* SetRegisterForLoop(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);
void Accept(NodeVisitor* visitor) override;
void Emit(RegExpCompiler* compiler, Trace* trace) override;
void GetQuickCheckDetails(QuickCheckDetails* details,
RegExpCompiler* compiler, int filled_in,
bool not_at_start) override;
void FillInBMInfo(Isolate* isolate, int offset, int budget,
BoyerMooreLookahead* bm, bool not_at_start) override;
ActionType action_type() { return action_type_; }
// TODO(erikcorry): We should allow some action nodes in greedy loops.
int GreedyLoopTextLength() override {
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_;
ActionNode(ActionType action_type, RegExpNode* on_success)
: SeqRegExpNode(on_success), action_type_(action_type) {}
ActionType action_type_;
friend class DotPrinterImpl;
};
class TextNode : public SeqRegExpNode {
public:
TextNode(ZoneList<TextElement>* elms, bool read_backward,
RegExpNode* on_success)
: SeqRegExpNode(on_success), elms_(elms), read_backward_(read_backward) {}
TextNode(RegExpCharacterClass* that, bool read_backward,
RegExpNode* on_success)
: SeqRegExpNode(on_success),
elms_(new (zone()) ZoneList<TextElement>(1, zone())),
read_backward_(read_backward) {
elms_->Add(TextElement::CharClass(that), zone());
}
// Create TextNode for a single character class for the given ranges.
static TextNode* CreateForCharacterRanges(Zone* zone,
ZoneList<CharacterRange>* ranges,
bool read_backward,
RegExpNode* on_success,
JSRegExp::Flags flags);
// Create TextNode for a surrogate pair with a range given for the
// lead and the trail surrogate each.
static TextNode* CreateForSurrogatePair(Zone* zone, CharacterRange lead,
CharacterRange trail,
bool read_backward,
RegExpNode* on_success,
JSRegExp::Flags flags);
void Accept(NodeVisitor* visitor) override;
void Emit(RegExpCompiler* compiler, Trace* trace) override;
void GetQuickCheckDetails(QuickCheckDetails* details,
RegExpCompiler* compiler, int characters_filled_in,
bool not_at_start) override;
ZoneList<TextElement>* elements() { return elms_; }
bool read_backward() { return read_backward_; }
void MakeCaseIndependent(Isolate* isolate, bool is_one_byte);
int GreedyLoopTextLength() override;
RegExpNode* GetSuccessorOfOmnivorousTextNode(
RegExpCompiler* compiler) override;
void FillInBMInfo(Isolate* isolate, int offset, int budget,
BoyerMooreLookahead* bm, bool not_at_start) override;
void CalculateOffsets();
RegExpNode* FilterOneByte(int depth) override;
int Length();
private:
enum TextEmitPassType {
NON_LATIN1_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(TextEmitPassType 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);
ZoneList<TextElement>* elms_;
bool read_backward_;
};
class AssertionNode : public SeqRegExpNode {
public:
enum AssertionType {
AT_END,
AT_START,
AT_BOUNDARY,
AT_NON_BOUNDARY,
AFTER_NEWLINE
};
static AssertionNode* AtEnd(RegExpNode* on_success) {
return new (on_success->zone()) AssertionNode(AT_END, on_success);
}
static AssertionNode* AtStart(RegExpNode* on_success) {
return new (on_success->zone()) AssertionNode(AT_START, on_success);
}
static AssertionNode* AtBoundary(RegExpNode* on_success) {
return new (on_success->zone()) AssertionNode(AT_BOUNDARY, on_success);
}
static AssertionNode* AtNonBoundary(RegExpNode* on_success) {
return new (on_success->zone()) AssertionNode(AT_NON_BOUNDARY, on_success);
}
static AssertionNode* AfterNewline(RegExpNode* on_success) {
return new (on_success->zone()) AssertionNode(AFTER_NEWLINE, on_success);
}
void Accept(NodeVisitor* visitor) override;
void Emit(RegExpCompiler* compiler, Trace* trace) override;
void GetQuickCheckDetails(QuickCheckDetails* details,
RegExpCompiler* compiler, int filled_in,
bool not_at_start) override;
void FillInBMInfo(Isolate* isolate, int offset, int budget,
BoyerMooreLookahead* bm, bool not_at_start) override;
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);
AssertionNode(AssertionType t, RegExpNode* on_success)
: SeqRegExpNode(on_success), assertion_type_(t) {}
AssertionType assertion_type_;
};
class BackReferenceNode : public SeqRegExpNode {
public:
BackReferenceNode(int start_reg, int end_reg, JSRegExp::Flags flags,
bool read_backward, RegExpNode* on_success)
: SeqRegExpNode(on_success),
start_reg_(start_reg),
end_reg_(end_reg),
flags_(flags),
read_backward_(read_backward) {}
void Accept(NodeVisitor* visitor) override;
int start_register() { return start_reg_; }
int end_register() { return end_reg_; }
bool read_backward() { return read_backward_; }
void Emit(RegExpCompiler* compiler, Trace* trace) override;
void GetQuickCheckDetails(QuickCheckDetails* details,
RegExpCompiler* compiler, int characters_filled_in,
bool not_at_start) override {
return;
}
void FillInBMInfo(Isolate* isolate, int offset, int budget,
BoyerMooreLookahead* bm, bool not_at_start) override;
private:
int start_reg_;
int end_reg_;
JSRegExp::Flags flags_;
bool read_backward_;
};
class EndNode : public RegExpNode {
public:
enum Action { ACCEPT, BACKTRACK, NEGATIVE_SUBMATCH_SUCCESS };
EndNode(Action action, Zone* zone) : RegExpNode(zone), action_(action) {}
void Accept(NodeVisitor* visitor) override;
void Emit(RegExpCompiler* compiler, Trace* trace) override;
void GetQuickCheckDetails(QuickCheckDetails* details,
RegExpCompiler* compiler, int characters_filled_in,
bool not_at_start) override {
// Returning 0 from EatsAtLeast should ensure we never get here.
UNREACHABLE();
}
void FillInBMInfo(Isolate* isolate, int offset, int budget,
BoyerMooreLookahead* bm, bool not_at_start) override {
// Returning 0 from EatsAtLeast should ensure we never get here.
UNREACHABLE();
}
private:
Action action_;
};
class NegativeSubmatchSuccess : public EndNode {
public:
NegativeSubmatchSuccess(int stack_pointer_reg, int position_reg,
int clear_capture_count, int clear_capture_start,
Zone* zone)
: EndNode(NEGATIVE_SUBMATCH_SUCCESS, zone),
stack_pointer_register_(stack_pointer_reg),
current_position_register_(position_reg),
clear_capture_count_(clear_capture_count),
clear_capture_start_(clear_capture_start) {}
void Emit(RegExpCompiler* compiler, Trace* trace) override;
private:
int stack_pointer_register_;
int current_position_register_;
int clear_capture_count_;
int clear_capture_start_;
};
class Guard : public ZoneObject {
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_;
};
class GuardedAlternative {
public:
explicit GuardedAlternative(RegExpNode* node)
: node_(node), guards_(nullptr) {}
void AddGuard(Guard* guard, Zone* zone);
RegExpNode* node() { return node_; }
void set_node(RegExpNode* node) { node_ = node; }
ZoneList<Guard*>* guards() { return guards_; }
private:
RegExpNode* node_;
ZoneList<Guard*>* guards_;
};
class AlternativeGeneration;
class ChoiceNode : public RegExpNode {
public:
explicit ChoiceNode(int expected_size, Zone* zone)
: RegExpNode(zone),
alternatives_(new (zone)
ZoneList<GuardedAlternative>(expected_size, zone)),
not_at_start_(false),
being_calculated_(false) {}
void Accept(NodeVisitor* visitor) override;
void AddAlternative(GuardedAlternative node) {
alternatives()->Add(node, zone());
}
ZoneList<GuardedAlternative>* alternatives() { return alternatives_; }
void Emit(RegExpCompiler* compiler, Trace* trace) override;
void GetQuickCheckDetails(QuickCheckDetails* details,
RegExpCompiler* compiler, int characters_filled_in,
bool not_at_start) override;
void FillInBMInfo(Isolate* isolate, int offset, int budget,
BoyerMooreLookahead* bm, bool not_at_start) override;
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(bool is_first) {
return true;
}
RegExpNode* FilterOneByte(int depth) override;
virtual bool read_backward() { return false; }
protected:
int GreedyLoopTextLengthForAlternative(GuardedAlternative* alternative);
ZoneList<GuardedAlternative>* alternatives_;
private:
template <typename...>
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);
void SetUpPreLoad(RegExpCompiler* compiler, Trace* current_trace,
PreloadState* preloads);
void AssertGuardsMentionRegisters(Trace* trace);
int EmitOptimizedUnanchoredSearch(RegExpCompiler* compiler, Trace* trace);
Trace* EmitGreedyLoop(RegExpCompiler* compiler, Trace* trace,
AlternativeGenerationList* alt_gens,
PreloadState* preloads,
GreedyLoopState* greedy_loop_state, int text_length);
void EmitChoices(RegExpCompiler* compiler,
AlternativeGenerationList* alt_gens, int first_choice,
Trace* trace, PreloadState* preloads);
// 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 NegativeLookaroundChoiceNode : public ChoiceNode {
public:
explicit NegativeLookaroundChoiceNode(GuardedAlternative this_must_fail,
GuardedAlternative then_do_this,
Zone* zone)
: ChoiceNode(2, zone) {
AddAlternative(this_must_fail);
AddAlternative(then_do_this);
}
void GetQuickCheckDetails(QuickCheckDetails* details,
RegExpCompiler* compiler, int characters_filled_in,
bool not_at_start) override;
void FillInBMInfo(Isolate* isolate, int offset, int budget,
BoyerMooreLookahead* bm, bool not_at_start) override {
continue_node()->FillInBMInfo(isolate, offset, budget - 1, bm,
not_at_start);
if (offset == 0) set_bm_info(not_at_start, bm);
}
static constexpr int kLookaroundIndex = 0;
static constexpr int kContinueIndex = 1;
RegExpNode* lookaround_node() {
return alternatives()->at(kLookaroundIndex).node();
}
RegExpNode* continue_node() {
return alternatives()->at(kContinueIndex).node();
}
// 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.
bool try_to_emit_quick_check_for_alternative(bool is_first) override {
return !is_first;
}
void Accept(NodeVisitor* visitor) override;
RegExpNode* FilterOneByte(int depth) override;
};
class LoopChoiceNode : public ChoiceNode {
public:
LoopChoiceNode(bool body_can_be_zero_length, bool read_backward,
int min_loop_iterations, Zone* zone)
: ChoiceNode(2, zone),
loop_node_(nullptr),
continue_node_(nullptr),
body_can_be_zero_length_(body_can_be_zero_length),
read_backward_(read_backward),
traversed_loop_initialization_node_(false),
min_loop_iterations_(min_loop_iterations) {}
void AddLoopAlternative(GuardedAlternative alt);
void AddContinueAlternative(GuardedAlternative alt);
void Emit(RegExpCompiler* compiler, Trace* trace) override;
void GetQuickCheckDetails(QuickCheckDetails* details,
RegExpCompiler* compiler, int characters_filled_in,
bool not_at_start) override;
void GetQuickCheckDetailsFromLoopEntry(QuickCheckDetails* details,
RegExpCompiler* compiler,
int characters_filled_in,
bool not_at_start) override;
void FillInBMInfo(Isolate* isolate, int offset, int budget,
BoyerMooreLookahead* bm, bool not_at_start) override;
EatsAtLeastInfo EatsAtLeastFromLoopEntry() override;
RegExpNode* loop_node() { return loop_node_; }
RegExpNode* continue_node() { return continue_node_; }
bool body_can_be_zero_length() { return body_can_be_zero_length_; }
int min_loop_iterations() const { return min_loop_iterations_; }
bool read_backward() override { return read_backward_; }
void Accept(NodeVisitor* visitor) override;
RegExpNode* FilterOneByte(int depth) override;
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_;
bool read_backward_;
// Temporary marker set only while generating quick check details. Represents
// whether GetQuickCheckDetails traversed the initialization node for this
// loop's counter. If so, we may be able to generate stricter quick checks
// because we know the loop node must match at least min_loop_iterations_
// times before the continuation node can match.
bool traversed_loop_initialization_node_;
// The minimum number of times the loop_node_ must match before the
// continue_node_ might be considered. This value can be temporarily decreased
// while generating quick check details, to represent the remaining iterations
// after the completed portion of the quick check details.
int min_loop_iterations_;
friend class IterationDecrementer;
friend class LoopInitializationMarker;
};
class NodeVisitor {
public:
virtual ~NodeVisitor() = default;
#define DECLARE_VISIT(Type) virtual void Visit##Type(Type##Node* that) = 0;
FOR_EACH_NODE_TYPE(DECLARE_VISIT)
#undef DECLARE_VISIT
};
} // namespace internal
} // namespace v8
#endif // V8_REGEXP_REGEXP_NODES_H_