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      1 // Copyright 2013 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_ARM64_REGEXP_MACRO_ASSEMBLER_ARM64_H_
      6 #define V8_REGEXP_ARM64_REGEXP_MACRO_ASSEMBLER_ARM64_H_
      7 
      8 #include "src/arm64/assembler-arm64.h"
      9 #include "src/macro-assembler.h"
     10 #include "src/regexp/regexp-macro-assembler.h"
     11 
     12 namespace v8 {
     13 namespace internal {
     14 
     15 
     16 #ifndef V8_INTERPRETED_REGEXP
     17 class RegExpMacroAssemblerARM64: public NativeRegExpMacroAssembler {
     18  public:
     19   RegExpMacroAssemblerARM64(Isolate* isolate, Zone* zone, Mode mode,
     20                             int registers_to_save);
     21   virtual ~RegExpMacroAssemblerARM64();
     22   virtual void AbortedCodeGeneration() { masm_->AbortedCodeGeneration(); }
     23   virtual int stack_limit_slack();
     24   virtual void AdvanceCurrentPosition(int by);
     25   virtual void AdvanceRegister(int reg, int by);
     26   virtual void Backtrack();
     27   virtual void Bind(Label* label);
     28   virtual void CheckAtStart(Label* on_at_start);
     29   virtual void CheckCharacter(unsigned c, Label* on_equal);
     30   virtual void CheckCharacterAfterAnd(unsigned c,
     31                                       unsigned mask,
     32                                       Label* on_equal);
     33   virtual void CheckCharacterGT(uc16 limit, Label* on_greater);
     34   virtual void CheckCharacterLT(uc16 limit, Label* on_less);
     35   virtual void CheckCharacters(Vector<const uc16> str,
     36                                int cp_offset,
     37                                Label* on_failure,
     38                                bool check_end_of_string);
     39   // A "greedy loop" is a loop that is both greedy and with a simple
     40   // body. It has a particularly simple implementation.
     41   virtual void CheckGreedyLoop(Label* on_tos_equals_current_position);
     42   virtual void CheckNotAtStart(int cp_offset, Label* on_not_at_start);
     43   virtual void CheckNotBackReference(int start_reg, bool read_backward,
     44                                      Label* on_no_match);
     45   virtual void CheckNotBackReferenceIgnoreCase(int start_reg,
     46                                                bool read_backward, bool unicode,
     47                                                Label* on_no_match);
     48   virtual void CheckNotCharacter(unsigned c, Label* on_not_equal);
     49   virtual void CheckNotCharacterAfterAnd(unsigned c,
     50                                          unsigned mask,
     51                                          Label* on_not_equal);
     52   virtual void CheckNotCharacterAfterMinusAnd(uc16 c,
     53                                               uc16 minus,
     54                                               uc16 mask,
     55                                               Label* on_not_equal);
     56   virtual void CheckCharacterInRange(uc16 from,
     57                                      uc16 to,
     58                                      Label* on_in_range);
     59   virtual void CheckCharacterNotInRange(uc16 from,
     60                                         uc16 to,
     61                                         Label* on_not_in_range);
     62   virtual void CheckBitInTable(Handle<ByteArray> table, Label* on_bit_set);
     63 
     64   // Checks whether the given offset from the current position is before
     65   // the end of the string.
     66   virtual void CheckPosition(int cp_offset, Label* on_outside_input);
     67   virtual bool CheckSpecialCharacterClass(uc16 type,
     68                                           Label* on_no_match);
     69   virtual void Fail();
     70   virtual Handle<HeapObject> GetCode(Handle<String> source);
     71   virtual void GoTo(Label* label);
     72   virtual void IfRegisterGE(int reg, int comparand, Label* if_ge);
     73   virtual void IfRegisterLT(int reg, int comparand, Label* if_lt);
     74   virtual void IfRegisterEqPos(int reg, Label* if_eq);
     75   virtual IrregexpImplementation Implementation();
     76   virtual void LoadCurrentCharacter(int cp_offset,
     77                                     Label* on_end_of_input,
     78                                     bool check_bounds = true,
     79                                     int characters = 1);
     80   virtual void PopCurrentPosition();
     81   virtual void PopRegister(int register_index);
     82   virtual void PushBacktrack(Label* label);
     83   virtual void PushCurrentPosition();
     84   virtual void PushRegister(int register_index,
     85                             StackCheckFlag check_stack_limit);
     86   virtual void ReadCurrentPositionFromRegister(int reg);
     87   virtual void ReadStackPointerFromRegister(int reg);
     88   virtual void SetCurrentPositionFromEnd(int by);
     89   virtual void SetRegister(int register_index, int to);
     90   virtual bool Succeed();
     91   virtual void WriteCurrentPositionToRegister(int reg, int cp_offset);
     92   virtual void ClearRegisters(int reg_from, int reg_to);
     93   virtual void WriteStackPointerToRegister(int reg);
     94 
     95   // Called from RegExp if the stack-guard is triggered.
     96   // If the code object is relocated, the return address is fixed before
     97   // returning.
     98   static int CheckStackGuardState(Address* return_address,
     99                                   Code* re_code,
    100                                   Address re_frame,
    101                                   int start_offset,
    102                                   const byte** input_start,
    103                                   const byte** input_end);
    104 
    105  private:
    106   // Above the frame pointer - Stored registers and stack passed parameters.
    107   // Callee-saved registers x19-x29, where x29 is the old frame pointer.
    108   static const int kCalleeSavedRegisters = 0;
    109   // Return address.
    110   // It is placed above the 11 callee-saved registers.
    111   static const int kReturnAddress = kCalleeSavedRegisters + 11 * kPointerSize;
    112   static const int kSecondaryReturnAddress = kReturnAddress + kPointerSize;
    113   // Stack parameter placed by caller.
    114   static const int kIsolate = kSecondaryReturnAddress + kPointerSize;
    115 
    116   // Below the frame pointer.
    117   // Register parameters stored by setup code.
    118   static const int kDirectCall = kCalleeSavedRegisters - kPointerSize;
    119   static const int kStackBase = kDirectCall - kPointerSize;
    120   static const int kOutputSize = kStackBase - kPointerSize;
    121   static const int kInput = kOutputSize - kPointerSize;
    122   // When adding local variables remember to push space for them in
    123   // the frame in GetCode.
    124   static const int kSuccessCounter = kInput - kPointerSize;
    125   // First position register address on the stack. Following positions are
    126   // below it. A position is a 32 bit value.
    127   static const int kFirstRegisterOnStack = kSuccessCounter - kWRegSize;
    128   // A capture is a 64 bit value holding two position.
    129   static const int kFirstCaptureOnStack = kSuccessCounter - kXRegSize;
    130 
    131   // Initial size of code buffer.
    132   static const size_t kRegExpCodeSize = 1024;
    133 
    134   // When initializing registers to a non-position value we can unroll
    135   // the loop. Set the limit of registers to unroll.
    136   static const int kNumRegistersToUnroll = 16;
    137 
    138   // We are using x0 to x7 as a register cache. Each hardware register must
    139   // contain one capture, that is two 32 bit registers. We can cache at most
    140   // 16 registers.
    141   static const int kNumCachedRegisters = 16;
    142 
    143   // Load a number of characters at the given offset from the
    144   // current position, into the current-character register.
    145   void LoadCurrentCharacterUnchecked(int cp_offset, int character_count);
    146 
    147   // Check whether preemption has been requested.
    148   void CheckPreemption();
    149 
    150   // Check whether we are exceeding the stack limit on the backtrack stack.
    151   void CheckStackLimit();
    152 
    153   // Generate a call to CheckStackGuardState.
    154   void CallCheckStackGuardState(Register scratch);
    155 
    156   // Location of a 32 bit position register.
    157   MemOperand register_location(int register_index);
    158 
    159   // Location of a 64 bit capture, combining two position registers.
    160   MemOperand capture_location(int register_index, Register scratch);
    161 
    162   // Register holding the current input position as negative offset from
    163   // the end of the string.
    164   Register current_input_offset() { return w21; }
    165 
    166   // The register containing the current character after LoadCurrentCharacter.
    167   Register current_character() { return w22; }
    168 
    169   // Register holding address of the end of the input string.
    170   Register input_end() { return x25; }
    171 
    172   // Register holding address of the start of the input string.
    173   Register input_start() { return x26; }
    174 
    175   // Register holding the offset from the start of the string where we should
    176   // start matching.
    177   Register start_offset() { return w27; }
    178 
    179   // Pointer to the output array's first element.
    180   Register output_array() { return x28; }
    181 
    182   // Register holding the frame address. Local variables, parameters and
    183   // regexp registers are addressed relative to this.
    184   Register frame_pointer() { return fp; }
    185 
    186   // The register containing the backtrack stack top. Provides a meaningful
    187   // name to the register.
    188   Register backtrack_stackpointer() { return x23; }
    189 
    190   // Register holding pointer to the current code object.
    191   Register code_pointer() { return x20; }
    192 
    193   // Register holding the value used for clearing capture registers.
    194   Register string_start_minus_one() { return w24; }
    195   // The top 32 bit of this register is used to store this value
    196   // twice. This is used for clearing more than one register at a time.
    197   Register twice_non_position_value() { return x24; }
    198 
    199   // Byte size of chars in the string to match (decided by the Mode argument)
    200   int char_size() { return static_cast<int>(mode_); }
    201 
    202   // Equivalent to a conditional branch to the label, unless the label
    203   // is NULL, in which case it is a conditional Backtrack.
    204   void BranchOrBacktrack(Condition condition, Label* to);
    205 
    206   // Compares reg against immmediate before calling BranchOrBacktrack.
    207   // It makes use of the Cbz and Cbnz instructions.
    208   void CompareAndBranchOrBacktrack(Register reg,
    209                                    int immediate,
    210                                    Condition condition,
    211                                    Label* to);
    212 
    213   inline void CallIf(Label* to, Condition condition);
    214 
    215   // Save and restore the link register on the stack in a way that
    216   // is GC-safe.
    217   inline void SaveLinkRegister();
    218   inline void RestoreLinkRegister();
    219 
    220   // Pushes the value of a register on the backtrack stack. Decrements the
    221   // stack pointer by a word size and stores the register's value there.
    222   inline void Push(Register source);
    223 
    224   // Pops a value from the backtrack stack. Reads the word at the stack pointer
    225   // and increments it by a word size.
    226   inline void Pop(Register target);
    227 
    228   // This state indicates where the register actually is.
    229   enum RegisterState {
    230     STACKED,     // Resides in memory.
    231     CACHED_LSW,  // Least Significant Word of a 64 bit hardware register.
    232     CACHED_MSW   // Most Significant Word of a 64 bit hardware register.
    233   };
    234 
    235   RegisterState GetRegisterState(int register_index) {
    236     DCHECK(register_index >= 0);
    237     if (register_index >= kNumCachedRegisters) {
    238       return STACKED;
    239     } else {
    240       if ((register_index % 2) == 0) {
    241         return CACHED_LSW;
    242       } else {
    243         return CACHED_MSW;
    244       }
    245     }
    246   }
    247 
    248   // Store helper that takes the state of the register into account.
    249   inline void StoreRegister(int register_index, Register source);
    250 
    251   // Returns a hardware W register that holds the value of the capture
    252   // register.
    253   //
    254   // This function will try to use an existing cache register (w0-w7) for the
    255   // result. Otherwise, it will load the value into maybe_result.
    256   //
    257   // If the returned register is anything other than maybe_result, calling code
    258   // must not write to it.
    259   inline Register GetRegister(int register_index, Register maybe_result);
    260 
    261   // Returns the harware register (x0-x7) holding the value of the capture
    262   // register.
    263   // This assumes that the state of the register is not STACKED.
    264   inline Register GetCachedRegister(int register_index);
    265 
    266   Isolate* isolate() const { return masm_->isolate(); }
    267 
    268   MacroAssembler* masm_;
    269 
    270   // Which mode to generate code for (LATIN1 or UC16).
    271   Mode mode_;
    272 
    273   // One greater than maximal register index actually used.
    274   int num_registers_;
    275 
    276   // Number of registers to output at the end (the saved registers
    277   // are always 0..num_saved_registers_-1)
    278   int num_saved_registers_;
    279 
    280   // Labels used internally.
    281   Label entry_label_;
    282   Label start_label_;
    283   Label success_label_;
    284   Label backtrack_label_;
    285   Label exit_label_;
    286   Label check_preempt_label_;
    287   Label stack_overflow_label_;
    288 };
    289 
    290 #endif  // V8_INTERPRETED_REGEXP
    291 
    292 
    293 }  // namespace internal
    294 }  // namespace v8
    295 
    296 #endif  // V8_REGEXP_ARM64_REGEXP_MACRO_ASSEMBLER_ARM64_H_
    297