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      1 // Copyright 2012 the V8 project authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #ifndef V8_REGEXP_MACRO_ASSEMBLER_H_
      6 #define V8_REGEXP_MACRO_ASSEMBLER_H_
      7 
      8 #include "src/ast.h"
      9 
     10 namespace v8 {
     11 namespace internal {
     12 
     13 struct DisjunctDecisionRow {
     14   RegExpCharacterClass cc;
     15   Label* on_match;
     16 };
     17 
     18 
     19 class RegExpMacroAssembler {
     20  public:
     21   // The implementation must be able to handle at least:
     22   static const int kMaxRegister = (1 << 16) - 1;
     23   static const int kMaxCPOffset = (1 << 15) - 1;
     24   static const int kMinCPOffset = -(1 << 15);
     25 
     26   static const int kTableSizeBits = 7;
     27   static const int kTableSize = 1 << kTableSizeBits;
     28   static const int kTableMask = kTableSize - 1;
     29 
     30   enum IrregexpImplementation {
     31     kIA32Implementation,
     32     kARMImplementation,
     33     kARM64Implementation,
     34     kMIPSImplementation,
     35     kX64Implementation,
     36     kX87Implementation,
     37     kBytecodeImplementation
     38   };
     39 
     40   enum StackCheckFlag {
     41     kNoStackLimitCheck = false,
     42     kCheckStackLimit = true
     43   };
     44 
     45   explicit RegExpMacroAssembler(Zone* zone);
     46   virtual ~RegExpMacroAssembler();
     47   // The maximal number of pushes between stack checks. Users must supply
     48   // kCheckStackLimit flag to push operations (instead of kNoStackLimitCheck)
     49   // at least once for every stack_limit() pushes that are executed.
     50   virtual int stack_limit_slack() = 0;
     51   virtual bool CanReadUnaligned() = 0;
     52   virtual void AdvanceCurrentPosition(int by) = 0;  // Signed cp change.
     53   virtual void AdvanceRegister(int reg, int by) = 0;  // r[reg] += by.
     54   // Continues execution from the position pushed on the top of the backtrack
     55   // stack by an earlier PushBacktrack(Label*).
     56   virtual void Backtrack() = 0;
     57   virtual void Bind(Label* label) = 0;
     58   virtual void CheckAtStart(Label* on_at_start) = 0;
     59   // Dispatch after looking the current character up in a 2-bits-per-entry
     60   // map.  The destinations vector has up to 4 labels.
     61   virtual void CheckCharacter(unsigned c, Label* on_equal) = 0;
     62   // Bitwise and the current character with the given constant and then
     63   // check for a match with c.
     64   virtual void CheckCharacterAfterAnd(unsigned c,
     65                                       unsigned and_with,
     66                                       Label* on_equal) = 0;
     67   virtual void CheckCharacterGT(uc16 limit, Label* on_greater) = 0;
     68   virtual void CheckCharacterLT(uc16 limit, Label* on_less) = 0;
     69   virtual void CheckGreedyLoop(Label* on_tos_equals_current_position) = 0;
     70   virtual void CheckNotAtStart(Label* on_not_at_start) = 0;
     71   virtual void CheckNotBackReference(int start_reg, Label* on_no_match) = 0;
     72   virtual void CheckNotBackReferenceIgnoreCase(int start_reg,
     73                                                Label* on_no_match) = 0;
     74   // Check the current character for a match with a literal character.  If we
     75   // fail to match then goto the on_failure label.  End of input always
     76   // matches.  If the label is NULL then we should pop a backtrack address off
     77   // the stack and go to that.
     78   virtual void CheckNotCharacter(unsigned c, Label* on_not_equal) = 0;
     79   virtual void CheckNotCharacterAfterAnd(unsigned c,
     80                                          unsigned and_with,
     81                                          Label* on_not_equal) = 0;
     82   // Subtract a constant from the current character, then and with the given
     83   // constant and then check for a match with c.
     84   virtual void CheckNotCharacterAfterMinusAnd(uc16 c,
     85                                               uc16 minus,
     86                                               uc16 and_with,
     87                                               Label* on_not_equal) = 0;
     88   virtual void CheckCharacterInRange(uc16 from,
     89                                      uc16 to,  // Both inclusive.
     90                                      Label* on_in_range) = 0;
     91   virtual void CheckCharacterNotInRange(uc16 from,
     92                                         uc16 to,  // Both inclusive.
     93                                         Label* on_not_in_range) = 0;
     94 
     95   // The current character (modulus the kTableSize) is looked up in the byte
     96   // array, and if the found byte is non-zero, we jump to the on_bit_set label.
     97   virtual void CheckBitInTable(Handle<ByteArray> table, Label* on_bit_set) = 0;
     98 
     99   // Checks whether the given offset from the current position is before
    100   // the end of the string.  May overwrite the current character.
    101   virtual void CheckPosition(int cp_offset, Label* on_outside_input) {
    102     LoadCurrentCharacter(cp_offset, on_outside_input, true);
    103   }
    104   // Check whether a standard/default character class matches the current
    105   // character. Returns false if the type of special character class does
    106   // not have custom support.
    107   // May clobber the current loaded character.
    108   virtual bool CheckSpecialCharacterClass(uc16 type,
    109                                           Label* on_no_match) {
    110     return false;
    111   }
    112   virtual void Fail() = 0;
    113   virtual Handle<HeapObject> GetCode(Handle<String> source) = 0;
    114   virtual void GoTo(Label* label) = 0;
    115   // Check whether a register is >= a given constant and go to a label if it
    116   // is.  Backtracks instead if the label is NULL.
    117   virtual void IfRegisterGE(int reg, int comparand, Label* if_ge) = 0;
    118   // Check whether a register is < a given constant and go to a label if it is.
    119   // Backtracks instead if the label is NULL.
    120   virtual void IfRegisterLT(int reg, int comparand, Label* if_lt) = 0;
    121   // Check whether a register is == to the current position and go to a
    122   // label if it is.
    123   virtual void IfRegisterEqPos(int reg, Label* if_eq) = 0;
    124   virtual IrregexpImplementation Implementation() = 0;
    125   virtual void LoadCurrentCharacter(int cp_offset,
    126                                     Label* on_end_of_input,
    127                                     bool check_bounds = true,
    128                                     int characters = 1) = 0;
    129   virtual void PopCurrentPosition() = 0;
    130   virtual void PopRegister(int register_index) = 0;
    131   // Pushes the label on the backtrack stack, so that a following Backtrack
    132   // will go to this label. Always checks the backtrack stack limit.
    133   virtual void PushBacktrack(Label* label) = 0;
    134   virtual void PushCurrentPosition() = 0;
    135   virtual void PushRegister(int register_index,
    136                             StackCheckFlag check_stack_limit) = 0;
    137   virtual void ReadCurrentPositionFromRegister(int reg) = 0;
    138   virtual void ReadStackPointerFromRegister(int reg) = 0;
    139   virtual void SetCurrentPositionFromEnd(int by) = 0;
    140   virtual void SetRegister(int register_index, int to) = 0;
    141   // Return whether the matching (with a global regexp) will be restarted.
    142   virtual bool Succeed() = 0;
    143   virtual void WriteCurrentPositionToRegister(int reg, int cp_offset) = 0;
    144   virtual void ClearRegisters(int reg_from, int reg_to) = 0;
    145   virtual void WriteStackPointerToRegister(int reg) = 0;
    146 
    147   // Controls the generation of large inlined constants in the code.
    148   void set_slow_safe(bool ssc) { slow_safe_compiler_ = ssc; }
    149   bool slow_safe() { return slow_safe_compiler_; }
    150 
    151   enum GlobalMode { NOT_GLOBAL, GLOBAL, GLOBAL_NO_ZERO_LENGTH_CHECK };
    152   // Set whether the regular expression has the global flag.  Exiting due to
    153   // a failure in a global regexp may still mean success overall.
    154   inline void set_global_mode(GlobalMode mode) { global_mode_ = mode; }
    155   inline bool global() { return global_mode_ != NOT_GLOBAL; }
    156   inline bool global_with_zero_length_check() {
    157     return global_mode_ == GLOBAL;
    158   }
    159 
    160   Zone* zone() const { return zone_; }
    161 
    162  private:
    163   bool slow_safe_compiler_;
    164   bool global_mode_;
    165   Zone* zone_;
    166 };
    167 
    168 
    169 #ifndef V8_INTERPRETED_REGEXP  // Avoid compiling unused code.
    170 
    171 class NativeRegExpMacroAssembler: public RegExpMacroAssembler {
    172  public:
    173   // Type of input string to generate code for.
    174   enum Mode { LATIN1 = 1, UC16 = 2 };
    175 
    176   // Result of calling generated native RegExp code.
    177   // RETRY: Something significant changed during execution, and the matching
    178   //        should be retried from scratch.
    179   // EXCEPTION: Something failed during execution. If no exception has been
    180   //        thrown, it's an internal out-of-memory, and the caller should
    181   //        throw the exception.
    182   // FAILURE: Matching failed.
    183   // SUCCESS: Matching succeeded, and the output array has been filled with
    184   //        capture positions.
    185   enum Result { RETRY = -2, EXCEPTION = -1, FAILURE = 0, SUCCESS = 1 };
    186 
    187   explicit NativeRegExpMacroAssembler(Zone* zone);
    188   virtual ~NativeRegExpMacroAssembler();
    189   virtual bool CanReadUnaligned();
    190 
    191   static Result Match(Handle<Code> regexp,
    192                       Handle<String> subject,
    193                       int* offsets_vector,
    194                       int offsets_vector_length,
    195                       int previous_index,
    196                       Isolate* isolate);
    197 
    198   // Compares two-byte strings case insensitively.
    199   // Called from generated RegExp code.
    200   static int CaseInsensitiveCompareUC16(Address byte_offset1,
    201                                         Address byte_offset2,
    202                                         size_t byte_length,
    203                                         Isolate* isolate);
    204 
    205   // Called from RegExp if the backtrack stack limit is hit.
    206   // Tries to expand the stack. Returns the new stack-pointer if
    207   // successful, and updates the stack_top address, or returns 0 if unable
    208   // to grow the stack.
    209   // This function must not trigger a garbage collection.
    210   static Address GrowStack(Address stack_pointer, Address* stack_top,
    211                            Isolate* isolate);
    212 
    213   static const byte* StringCharacterPosition(String* subject, int start_index);
    214 
    215   // Byte map of one byte characters with a 0xff if the character is a word
    216   // character (digit, letter or underscore) and 0x00 otherwise.
    217   // Used by generated RegExp code.
    218   static const byte word_character_map[256];
    219 
    220   static Address word_character_map_address() {
    221     return const_cast<Address>(&word_character_map[0]);
    222   }
    223 
    224   static Result Execute(Code* code,
    225                         String* input,
    226                         int start_offset,
    227                         const byte* input_start,
    228                         const byte* input_end,
    229                         int* output,
    230                         int output_size,
    231                         Isolate* isolate);
    232 };
    233 
    234 #endif  // V8_INTERPRETED_REGEXP
    235 
    236 } }  // namespace v8::internal
    237 
    238 #endif  // V8_REGEXP_MACRO_ASSEMBLER_H_
    239