| // Copyright 2011 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. |
| |
| // Features shared by parsing and pre-parsing scanners. |
| |
| #ifndef V8_SCANNER_H_ |
| #define V8_SCANNER_H_ |
| |
| #include "allocation.h" |
| #include "char-predicates.h" |
| #include "checks.h" |
| #include "globals.h" |
| #include "token.h" |
| #include "unicode-inl.h" |
| #include "utils.h" |
| |
| namespace v8 { |
| namespace internal { |
| |
| |
| // General collection of (multi-)bit-flags that can be passed to scanners and |
| // parsers to signify their (initial) mode of operation. |
| enum ParsingFlags { |
| kNoParsingFlags = 0, |
| // Embed LanguageMode values in parsing flags, i.e., equivalent to: |
| // CLASSIC_MODE = 0, |
| // STRICT_MODE, |
| // EXTENDED_MODE, |
| kLanguageModeMask = 0x03, |
| kAllowLazy = 0x04, |
| kAllowNativesSyntax = 0x08, |
| kAllowModules = 0x10 |
| }; |
| |
| STATIC_ASSERT((kLanguageModeMask & CLASSIC_MODE) == CLASSIC_MODE); |
| STATIC_ASSERT((kLanguageModeMask & STRICT_MODE) == STRICT_MODE); |
| STATIC_ASSERT((kLanguageModeMask & EXTENDED_MODE) == EXTENDED_MODE); |
| |
| |
| // Returns the value (0 .. 15) of a hexadecimal character c. |
| // If c is not a legal hexadecimal character, returns a value < 0. |
| inline int HexValue(uc32 c) { |
| c -= '0'; |
| if (static_cast<unsigned>(c) <= 9) return c; |
| c = (c | 0x20) - ('a' - '0'); // detect 0x11..0x16 and 0x31..0x36. |
| if (static_cast<unsigned>(c) <= 5) return c + 10; |
| return -1; |
| } |
| |
| |
| // --------------------------------------------------------------------- |
| // Buffered stream of UTF-16 code units, using an internal UTF-16 buffer. |
| // A code unit is a 16 bit value representing either a 16 bit code point |
| // or one part of a surrogate pair that make a single 21 bit code point. |
| |
| class Utf16CharacterStream { |
| public: |
| Utf16CharacterStream() : pos_(0) { } |
| virtual ~Utf16CharacterStream() { } |
| |
| // Returns and advances past the next UTF-16 code unit in the input |
| // stream. If there are no more code units, it returns a negative |
| // value. |
| inline uc32 Advance() { |
| if (buffer_cursor_ < buffer_end_ || ReadBlock()) { |
| pos_++; |
| return static_cast<uc32>(*(buffer_cursor_++)); |
| } |
| // Note: currently the following increment is necessary to avoid a |
| // parser problem! The scanner treats the final kEndOfInput as |
| // a code unit with a position, and does math relative to that |
| // position. |
| pos_++; |
| |
| return kEndOfInput; |
| } |
| |
| // Return the current position in the code unit stream. |
| // Starts at zero. |
| inline unsigned pos() const { return pos_; } |
| |
| // Skips forward past the next code_unit_count UTF-16 code units |
| // in the input, or until the end of input if that comes sooner. |
| // Returns the number of code units actually skipped. If less |
| // than code_unit_count, |
| inline unsigned SeekForward(unsigned code_unit_count) { |
| unsigned buffered_chars = |
| static_cast<unsigned>(buffer_end_ - buffer_cursor_); |
| if (code_unit_count <= buffered_chars) { |
| buffer_cursor_ += code_unit_count; |
| pos_ += code_unit_count; |
| return code_unit_count; |
| } |
| return SlowSeekForward(code_unit_count); |
| } |
| |
| // Pushes back the most recently read UTF-16 code unit (or negative |
| // value if at end of input), i.e., the value returned by the most recent |
| // call to Advance. |
| // Must not be used right after calling SeekForward. |
| virtual void PushBack(int32_t code_unit) = 0; |
| |
| protected: |
| static const uc32 kEndOfInput = -1; |
| |
| // Ensures that the buffer_cursor_ points to the code_unit at |
| // position pos_ of the input, if possible. If the position |
| // is at or after the end of the input, return false. If there |
| // are more code_units available, return true. |
| virtual bool ReadBlock() = 0; |
| virtual unsigned SlowSeekForward(unsigned code_unit_count) = 0; |
| |
| const uc16* buffer_cursor_; |
| const uc16* buffer_end_; |
| unsigned pos_; |
| }; |
| |
| |
| class UnicodeCache { |
| // --------------------------------------------------------------------- |
| // Caching predicates used by scanners. |
| public: |
| UnicodeCache() {} |
| typedef unibrow::Utf8Decoder<512> Utf8Decoder; |
| |
| StaticResource<Utf8Decoder>* utf8_decoder() { |
| return &utf8_decoder_; |
| } |
| |
| bool IsIdentifierStart(unibrow::uchar c) { return kIsIdentifierStart.get(c); } |
| bool IsIdentifierPart(unibrow::uchar c) { return kIsIdentifierPart.get(c); } |
| bool IsLineTerminator(unibrow::uchar c) { return kIsLineTerminator.get(c); } |
| bool IsWhiteSpace(unibrow::uchar c) { return kIsWhiteSpace.get(c); } |
| |
| private: |
| unibrow::Predicate<IdentifierStart, 128> kIsIdentifierStart; |
| unibrow::Predicate<IdentifierPart, 128> kIsIdentifierPart; |
| unibrow::Predicate<unibrow::LineTerminator, 128> kIsLineTerminator; |
| unibrow::Predicate<unibrow::WhiteSpace, 128> kIsWhiteSpace; |
| StaticResource<Utf8Decoder> utf8_decoder_; |
| |
| DISALLOW_COPY_AND_ASSIGN(UnicodeCache); |
| }; |
| |
| |
| // ---------------------------------------------------------------------------- |
| // LiteralBuffer - Collector of chars of literals. |
| |
| class LiteralBuffer { |
| public: |
| LiteralBuffer() : is_ascii_(true), position_(0), backing_store_() { } |
| |
| ~LiteralBuffer() { |
| if (backing_store_.length() > 0) { |
| backing_store_.Dispose(); |
| } |
| } |
| |
| INLINE(void AddChar(uint32_t code_unit)) { |
| if (position_ >= backing_store_.length()) ExpandBuffer(); |
| if (is_ascii_) { |
| if (code_unit < kMaxAsciiCharCodeU) { |
| backing_store_[position_] = static_cast<byte>(code_unit); |
| position_ += kASCIISize; |
| return; |
| } |
| ConvertToUtf16(); |
| } |
| ASSERT(code_unit < 0x10000u); |
| *reinterpret_cast<uc16*>(&backing_store_[position_]) = code_unit; |
| position_ += kUC16Size; |
| } |
| |
| bool is_ascii() { return is_ascii_; } |
| |
| Vector<const uc16> utf16_literal() { |
| ASSERT(!is_ascii_); |
| ASSERT((position_ & 0x1) == 0); |
| return Vector<const uc16>( |
| reinterpret_cast<const uc16*>(backing_store_.start()), |
| position_ >> 1); |
| } |
| |
| Vector<const char> ascii_literal() { |
| ASSERT(is_ascii_); |
| return Vector<const char>( |
| reinterpret_cast<const char*>(backing_store_.start()), |
| position_); |
| } |
| |
| int length() { |
| return is_ascii_ ? position_ : (position_ >> 1); |
| } |
| |
| void Reset() { |
| position_ = 0; |
| is_ascii_ = true; |
| } |
| |
| private: |
| static const int kInitialCapacity = 16; |
| static const int kGrowthFactory = 4; |
| static const int kMinConversionSlack = 256; |
| static const int kMaxGrowth = 1 * MB; |
| inline int NewCapacity(int min_capacity) { |
| int capacity = Max(min_capacity, backing_store_.length()); |
| int new_capacity = Min(capacity * kGrowthFactory, capacity + kMaxGrowth); |
| return new_capacity; |
| } |
| |
| void ExpandBuffer() { |
| Vector<byte> new_store = Vector<byte>::New(NewCapacity(kInitialCapacity)); |
| memcpy(new_store.start(), backing_store_.start(), position_); |
| backing_store_.Dispose(); |
| backing_store_ = new_store; |
| } |
| |
| void ConvertToUtf16() { |
| ASSERT(is_ascii_); |
| Vector<byte> new_store; |
| int new_content_size = position_ * kUC16Size; |
| if (new_content_size >= backing_store_.length()) { |
| // Ensure room for all currently read code units as UC16 as well |
| // as the code unit about to be stored. |
| new_store = Vector<byte>::New(NewCapacity(new_content_size)); |
| } else { |
| new_store = backing_store_; |
| } |
| char* src = reinterpret_cast<char*>(backing_store_.start()); |
| uc16* dst = reinterpret_cast<uc16*>(new_store.start()); |
| for (int i = position_ - 1; i >= 0; i--) { |
| dst[i] = src[i]; |
| } |
| if (new_store.start() != backing_store_.start()) { |
| backing_store_.Dispose(); |
| backing_store_ = new_store; |
| } |
| position_ = new_content_size; |
| is_ascii_ = false; |
| } |
| |
| bool is_ascii_; |
| int position_; |
| Vector<byte> backing_store_; |
| |
| DISALLOW_COPY_AND_ASSIGN(LiteralBuffer); |
| }; |
| |
| |
| // ---------------------------------------------------------------------------- |
| // JavaScript Scanner. |
| |
| class Scanner { |
| public: |
| // Scoped helper for literal recording. Automatically drops the literal |
| // if aborting the scanning before it's complete. |
| class LiteralScope { |
| public: |
| explicit LiteralScope(Scanner* self) |
| : scanner_(self), complete_(false) { |
| scanner_->StartLiteral(); |
| } |
| ~LiteralScope() { |
| if (!complete_) scanner_->DropLiteral(); |
| } |
| void Complete() { |
| scanner_->TerminateLiteral(); |
| complete_ = true; |
| } |
| |
| private: |
| Scanner* scanner_; |
| bool complete_; |
| }; |
| |
| // Representation of an interval of source positions. |
| struct Location { |
| Location(int b, int e) : beg_pos(b), end_pos(e) { } |
| Location() : beg_pos(0), end_pos(0) { } |
| |
| bool IsValid() const { |
| return beg_pos >= 0 && end_pos >= beg_pos; |
| } |
| |
| static Location invalid() { return Location(-1, -1); } |
| |
| int beg_pos; |
| int end_pos; |
| }; |
| |
| // -1 is outside of the range of any real source code. |
| static const int kNoOctalLocation = -1; |
| |
| explicit Scanner(UnicodeCache* scanner_contants); |
| |
| void Initialize(Utf16CharacterStream* source); |
| |
| // Returns the next token and advances input. |
| Token::Value Next(); |
| // Returns the current token again. |
| Token::Value current_token() { return current_.token; } |
| // Returns the location information for the current token |
| // (the token last returned by Next()). |
| Location location() const { return current_.location; } |
| // Returns the literal string, if any, for the current token (the |
| // token last returned by Next()). The string is 0-terminated. |
| // Literal strings are collected for identifiers, strings, and |
| // numbers. |
| // These functions only give the correct result if the literal |
| // was scanned between calls to StartLiteral() and TerminateLiteral(). |
| Vector<const char> literal_ascii_string() { |
| ASSERT_NOT_NULL(current_.literal_chars); |
| return current_.literal_chars->ascii_literal(); |
| } |
| Vector<const uc16> literal_utf16_string() { |
| ASSERT_NOT_NULL(current_.literal_chars); |
| return current_.literal_chars->utf16_literal(); |
| } |
| bool is_literal_ascii() { |
| ASSERT_NOT_NULL(current_.literal_chars); |
| return current_.literal_chars->is_ascii(); |
| } |
| int literal_length() const { |
| ASSERT_NOT_NULL(current_.literal_chars); |
| return current_.literal_chars->length(); |
| } |
| |
| bool literal_contains_escapes() const { |
| Location location = current_.location; |
| int source_length = (location.end_pos - location.beg_pos); |
| if (current_.token == Token::STRING) { |
| // Subtract delimiters. |
| source_length -= 2; |
| } |
| return current_.literal_chars->length() != source_length; |
| } |
| |
| // Similar functions for the upcoming token. |
| |
| // One token look-ahead (past the token returned by Next()). |
| Token::Value peek() const { return next_.token; } |
| |
| Location peek_location() const { return next_.location; } |
| |
| // Returns the literal string for the next token (the token that |
| // would be returned if Next() were called). |
| Vector<const char> next_literal_ascii_string() { |
| ASSERT_NOT_NULL(next_.literal_chars); |
| return next_.literal_chars->ascii_literal(); |
| } |
| Vector<const uc16> next_literal_utf16_string() { |
| ASSERT_NOT_NULL(next_.literal_chars); |
| return next_.literal_chars->utf16_literal(); |
| } |
| bool is_next_literal_ascii() { |
| ASSERT_NOT_NULL(next_.literal_chars); |
| return next_.literal_chars->is_ascii(); |
| } |
| int next_literal_length() const { |
| ASSERT_NOT_NULL(next_.literal_chars); |
| return next_.literal_chars->length(); |
| } |
| |
| UnicodeCache* unicode_cache() { return unicode_cache_; } |
| |
| static const int kCharacterLookaheadBufferSize = 1; |
| |
| // Scans octal escape sequence. Also accepts "\0" decimal escape sequence. |
| uc32 ScanOctalEscape(uc32 c, int length); |
| |
| // Returns the location of the last seen octal literal. |
| Location octal_position() const { return octal_pos_; } |
| void clear_octal_position() { octal_pos_ = Location::invalid(); } |
| |
| // Seek forward to the given position. This operation does not |
| // work in general, for instance when there are pushed back |
| // characters, but works for seeking forward until simple delimiter |
| // tokens, which is what it is used for. |
| void SeekForward(int pos); |
| |
| bool HarmonyScoping() const { |
| return harmony_scoping_; |
| } |
| void SetHarmonyScoping(bool scoping) { |
| harmony_scoping_ = scoping; |
| } |
| bool HarmonyModules() const { |
| return harmony_modules_; |
| } |
| void SetHarmonyModules(bool modules) { |
| harmony_modules_ = modules; |
| } |
| |
| |
| // Returns true if there was a line terminator before the peek'ed token, |
| // possibly inside a multi-line comment. |
| bool HasAnyLineTerminatorBeforeNext() const { |
| return has_line_terminator_before_next_ || |
| has_multiline_comment_before_next_; |
| } |
| |
| // Scans the input as a regular expression pattern, previous |
| // character(s) must be /(=). Returns true if a pattern is scanned. |
| bool ScanRegExpPattern(bool seen_equal); |
| // Returns true if regexp flags are scanned (always since flags can |
| // be empty). |
| bool ScanRegExpFlags(); |
| |
| private: |
| // The current and look-ahead token. |
| struct TokenDesc { |
| Token::Value token; |
| Location location; |
| LiteralBuffer* literal_chars; |
| }; |
| |
| // Call this after setting source_ to the input. |
| void Init() { |
| // Set c0_ (one character ahead) |
| STATIC_ASSERT(kCharacterLookaheadBufferSize == 1); |
| Advance(); |
| // Initialize current_ to not refer to a literal. |
| current_.literal_chars = NULL; |
| } |
| |
| // Literal buffer support |
| inline void StartLiteral() { |
| LiteralBuffer* free_buffer = (current_.literal_chars == &literal_buffer1_) ? |
| &literal_buffer2_ : &literal_buffer1_; |
| free_buffer->Reset(); |
| next_.literal_chars = free_buffer; |
| } |
| |
| INLINE(void AddLiteralChar(uc32 c)) { |
| ASSERT_NOT_NULL(next_.literal_chars); |
| next_.literal_chars->AddChar(c); |
| } |
| |
| // Complete scanning of a literal. |
| inline void TerminateLiteral() { |
| // Does nothing in the current implementation. |
| } |
| |
| // Stops scanning of a literal and drop the collected characters, |
| // e.g., due to an encountered error. |
| inline void DropLiteral() { |
| next_.literal_chars = NULL; |
| } |
| |
| inline void AddLiteralCharAdvance() { |
| AddLiteralChar(c0_); |
| Advance(); |
| } |
| |
| // Low-level scanning support. |
| void Advance() { c0_ = source_->Advance(); } |
| void PushBack(uc32 ch) { |
| source_->PushBack(c0_); |
| c0_ = ch; |
| } |
| |
| inline Token::Value Select(Token::Value tok) { |
| Advance(); |
| return tok; |
| } |
| |
| inline Token::Value Select(uc32 next, Token::Value then, Token::Value else_) { |
| Advance(); |
| if (c0_ == next) { |
| Advance(); |
| return then; |
| } else { |
| return else_; |
| } |
| } |
| |
| uc32 ScanHexNumber(int expected_length); |
| |
| // Scans a single JavaScript token. |
| void Scan(); |
| |
| bool SkipWhiteSpace(); |
| Token::Value SkipSingleLineComment(); |
| Token::Value SkipMultiLineComment(); |
| // Scans a possible HTML comment -- begins with '<!'. |
| Token::Value ScanHtmlComment(); |
| |
| void ScanDecimalDigits(); |
| Token::Value ScanNumber(bool seen_period); |
| Token::Value ScanIdentifierOrKeyword(); |
| Token::Value ScanIdentifierSuffix(LiteralScope* literal); |
| |
| Token::Value ScanString(); |
| |
| // Scans an escape-sequence which is part of a string and adds the |
| // decoded character to the current literal. Returns true if a pattern |
| // is scanned. |
| bool ScanEscape(); |
| // Decodes a Unicode escape-sequence which is part of an identifier. |
| // If the escape sequence cannot be decoded the result is kBadChar. |
| uc32 ScanIdentifierUnicodeEscape(); |
| // Scans a Unicode escape-sequence and adds its characters, |
| // uninterpreted, to the current literal. Used for parsing RegExp |
| // flags. |
| bool ScanLiteralUnicodeEscape(); |
| |
| // Return the current source position. |
| int source_pos() { |
| return source_->pos() - kCharacterLookaheadBufferSize; |
| } |
| |
| UnicodeCache* unicode_cache_; |
| |
| // Buffers collecting literal strings, numbers, etc. |
| LiteralBuffer literal_buffer1_; |
| LiteralBuffer literal_buffer2_; |
| |
| TokenDesc current_; // desc for current token (as returned by Next()) |
| TokenDesc next_; // desc for next token (one token look-ahead) |
| |
| // Input stream. Must be initialized to an Utf16CharacterStream. |
| Utf16CharacterStream* source_; |
| |
| |
| // Start position of the octal literal last scanned. |
| Location octal_pos_; |
| |
| // One Unicode character look-ahead; c0_ < 0 at the end of the input. |
| uc32 c0_; |
| |
| // Whether there is a line terminator whitespace character after |
| // the current token, and before the next. Does not count newlines |
| // inside multiline comments. |
| bool has_line_terminator_before_next_; |
| // Whether there is a multi-line comment that contains a |
| // line-terminator after the current token, and before the next. |
| bool has_multiline_comment_before_next_; |
| // Whether we scan 'let' as a keyword for harmony block-scoped let bindings. |
| bool harmony_scoping_; |
| // Whether we scan 'module', 'import', 'export' as keywords. |
| bool harmony_modules_; |
| }; |
| |
| } } // namespace v8::internal |
| |
| #endif // V8_SCANNER_H_ |