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      1 // Copyright 2006-2008 the V8 project authors. All rights reserved.
      2 // Redistribution and use in source and binary forms, with or without
      3 // modification, are permitted provided that the following conditions are
      4 // met:
      5 //
      6 //     * Redistributions of source code must retain the above copyright
      7 //       notice, this list of conditions and the following disclaimer.
      8 //     * Redistributions in binary form must reproduce the above
      9 //       copyright notice, this list of conditions and the following
     10 //       disclaimer in the documentation and/or other materials provided
     11 //       with the distribution.
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     13 //       contributors may be used to endorse or promote products derived
     14 //       from this software without specific prior written permission.
     15 //
     16 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     17 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     18 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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     26 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     27 
     28 #ifndef V8_ARM_REGEXP_MACRO_ASSEMBLER_ARM_H_
     29 #define V8_ARM_REGEXP_MACRO_ASSEMBLER_ARM_H_
     30 
     31 #include "arm/assembler-arm.h"
     32 #include "arm/assembler-arm-inl.h"
     33 
     34 namespace v8 {
     35 namespace internal {
     36 
     37 
     38 #ifdef V8_INTERPRETED_REGEXP
     39 class RegExpMacroAssemblerARM: public RegExpMacroAssembler {
     40  public:
     41   RegExpMacroAssemblerARM();
     42   virtual ~RegExpMacroAssemblerARM();
     43 };
     44 
     45 #else  // V8_INTERPRETED_REGEXP
     46 class RegExpMacroAssemblerARM: public NativeRegExpMacroAssembler {
     47  public:
     48   RegExpMacroAssemblerARM(Mode mode, int registers_to_save);
     49   virtual ~RegExpMacroAssemblerARM();
     50   virtual int stack_limit_slack();
     51   virtual void AdvanceCurrentPosition(int by);
     52   virtual void AdvanceRegister(int reg, int by);
     53   virtual void Backtrack();
     54   virtual void Bind(Label* label);
     55   virtual void CheckAtStart(Label* on_at_start);
     56   virtual void CheckCharacter(unsigned c, Label* on_equal);
     57   virtual void CheckCharacterAfterAnd(unsigned c,
     58                                       unsigned mask,
     59                                       Label* on_equal);
     60   virtual void CheckCharacterGT(uc16 limit, Label* on_greater);
     61   virtual void CheckCharacterLT(uc16 limit, Label* on_less);
     62   virtual void CheckCharacters(Vector<const uc16> str,
     63                                int cp_offset,
     64                                Label* on_failure,
     65                                bool check_end_of_string);
     66   // A "greedy loop" is a loop that is both greedy and with a simple
     67   // body. It has a particularly simple implementation.
     68   virtual void CheckGreedyLoop(Label* on_tos_equals_current_position);
     69   virtual void CheckNotAtStart(Label* on_not_at_start);
     70   virtual void CheckNotBackReference(int start_reg, Label* on_no_match);
     71   virtual void CheckNotBackReferenceIgnoreCase(int start_reg,
     72                                                Label* on_no_match);
     73   virtual void CheckNotRegistersEqual(int reg1, int reg2, Label* on_not_equal);
     74   virtual void CheckNotCharacter(unsigned c, Label* on_not_equal);
     75   virtual void CheckNotCharacterAfterAnd(unsigned c,
     76                                          unsigned mask,
     77                                          Label* on_not_equal);
     78   virtual void CheckNotCharacterAfterMinusAnd(uc16 c,
     79                                               uc16 minus,
     80                                               uc16 mask,
     81                                               Label* on_not_equal);
     82   // Checks whether the given offset from the current position is before
     83   // the end of the string.
     84   virtual void CheckPosition(int cp_offset, Label* on_outside_input);
     85   virtual bool CheckSpecialCharacterClass(uc16 type,
     86                                           Label* on_no_match);
     87   virtual void Fail();
     88   virtual Handle<HeapObject> GetCode(Handle<String> source);
     89   virtual void GoTo(Label* label);
     90   virtual void IfRegisterGE(int reg, int comparand, Label* if_ge);
     91   virtual void IfRegisterLT(int reg, int comparand, Label* if_lt);
     92   virtual void IfRegisterEqPos(int reg, Label* if_eq);
     93   virtual IrregexpImplementation Implementation();
     94   virtual void LoadCurrentCharacter(int cp_offset,
     95                                     Label* on_end_of_input,
     96                                     bool check_bounds = true,
     97                                     int characters = 1);
     98   virtual void PopCurrentPosition();
     99   virtual void PopRegister(int register_index);
    100   virtual void PushBacktrack(Label* label);
    101   virtual void PushCurrentPosition();
    102   virtual void PushRegister(int register_index,
    103                             StackCheckFlag check_stack_limit);
    104   virtual void ReadCurrentPositionFromRegister(int reg);
    105   virtual void ReadStackPointerFromRegister(int reg);
    106   virtual void SetCurrentPositionFromEnd(int by);
    107   virtual void SetRegister(int register_index, int to);
    108   virtual void Succeed();
    109   virtual void WriteCurrentPositionToRegister(int reg, int cp_offset);
    110   virtual void ClearRegisters(int reg_from, int reg_to);
    111   virtual void WriteStackPointerToRegister(int reg);
    112 
    113   // Called from RegExp if the stack-guard is triggered.
    114   // If the code object is relocated, the return address is fixed before
    115   // returning.
    116   static int CheckStackGuardState(Address* return_address,
    117                                   Code* re_code,
    118                                   Address re_frame);
    119 
    120  private:
    121   // Offsets from frame_pointer() of function parameters and stored registers.
    122   static const int kFramePointer = 0;
    123 
    124   // Above the frame pointer - Stored registers and stack passed parameters.
    125   // Register 4..11.
    126   static const int kStoredRegisters = kFramePointer;
    127   // Return address (stored from link register, read into pc on return).
    128   static const int kReturnAddress = kStoredRegisters + 8 * kPointerSize;
    129   static const int kSecondaryReturnAddress = kReturnAddress + kPointerSize;
    130   // Stack parameters placed by caller.
    131   static const int kRegisterOutput = kSecondaryReturnAddress + kPointerSize;
    132   static const int kStackHighEnd = kRegisterOutput + kPointerSize;
    133   static const int kDirectCall = kStackHighEnd + kPointerSize;
    134   static const int kIsolate = kDirectCall + kPointerSize;
    135 
    136   // Below the frame pointer.
    137   // Register parameters stored by setup code.
    138   static const int kInputEnd = kFramePointer - kPointerSize;
    139   static const int kInputStart = kInputEnd - kPointerSize;
    140   static const int kStartIndex = kInputStart - kPointerSize;
    141   static const int kInputString = kStartIndex - kPointerSize;
    142   // When adding local variables remember to push space for them in
    143   // the frame in GetCode.
    144   static const int kInputStartMinusOne = kInputString - kPointerSize;
    145   static const int kAtStart = kInputStartMinusOne - kPointerSize;
    146   // First register address. Following registers are below it on the stack.
    147   static const int kRegisterZero = kAtStart - kPointerSize;
    148 
    149   // Initial size of code buffer.
    150   static const size_t kRegExpCodeSize = 1024;
    151 
    152   static const int kBacktrackConstantPoolSize = 4;
    153 
    154   // Load a number of characters at the given offset from the
    155   // current position, into the current-character register.
    156   void LoadCurrentCharacterUnchecked(int cp_offset, int character_count);
    157 
    158   // Check whether preemption has been requested.
    159   void CheckPreemption();
    160 
    161   // Check whether we are exceeding the stack limit on the backtrack stack.
    162   void CheckStackLimit();
    163 
    164   void EmitBacktrackConstantPool();
    165   int GetBacktrackConstantPoolEntry();
    166 
    167 
    168   // Generate a call to CheckStackGuardState.
    169   void CallCheckStackGuardState(Register scratch);
    170 
    171   // The ebp-relative location of a regexp register.
    172   MemOperand register_location(int register_index);
    173 
    174   // Register holding the current input position as negative offset from
    175   // the end of the string.
    176   inline Register current_input_offset() { return r6; }
    177 
    178   // The register containing the current character after LoadCurrentCharacter.
    179   inline Register current_character() { return r7; }
    180 
    181   // Register holding address of the end of the input string.
    182   inline Register end_of_input_address() { return r10; }
    183 
    184   // Register holding the frame address. Local variables, parameters and
    185   // regexp registers are addressed relative to this.
    186   inline Register frame_pointer() { return fp; }
    187 
    188   // The register containing the backtrack stack top. Provides a meaningful
    189   // name to the register.
    190   inline Register backtrack_stackpointer() { return r8; }
    191 
    192   // Register holding pointer to the current code object.
    193   inline Register code_pointer() { return r5; }
    194 
    195   // Byte size of chars in the string to match (decided by the Mode argument)
    196   inline int char_size() { return static_cast<int>(mode_); }
    197 
    198   // Equivalent to a conditional branch to the label, unless the label
    199   // is NULL, in which case it is a conditional Backtrack.
    200   void BranchOrBacktrack(Condition condition, Label* to);
    201 
    202   // Call and return internally in the generated code in a way that
    203   // is GC-safe (i.e., doesn't leave absolute code addresses on the stack)
    204   inline void SafeCall(Label* to, Condition cond = al);
    205   inline void SafeReturn();
    206   inline void SafeCallTarget(Label* name);
    207 
    208   // Pushes the value of a register on the backtrack stack. Decrements the
    209   // stack pointer by a word size and stores the register's value there.
    210   inline void Push(Register source);
    211 
    212   // Pops a value from the backtrack stack. Reads the word at the stack pointer
    213   // and increments it by a word size.
    214   inline void Pop(Register target);
    215 
    216   // Calls a C function and cleans up the frame alignment done by
    217   // by FrameAlign. The called function *is* allowed to trigger a garbage
    218   // collection, but may not take more than four arguments (no arguments
    219   // passed on the stack), and the first argument will be a pointer to the
    220   // return address.
    221   inline void CallCFunctionUsingStub(ExternalReference function,
    222                                      int num_arguments);
    223 
    224 
    225   MacroAssembler* masm_;
    226 
    227   // Which mode to generate code for (ASCII or UC16).
    228   Mode mode_;
    229 
    230   // One greater than maximal register index actually used.
    231   int num_registers_;
    232 
    233   // Number of registers to output at the end (the saved registers
    234   // are always 0..num_saved_registers_-1)
    235   int num_saved_registers_;
    236 
    237   // Manage a small pre-allocated pool for writing label targets
    238   // to for pushing backtrack addresses.
    239   int backtrack_constant_pool_offset_;
    240   int backtrack_constant_pool_capacity_;
    241 
    242   // Labels used internally.
    243   Label entry_label_;
    244   Label start_label_;
    245   Label success_label_;
    246   Label backtrack_label_;
    247   Label exit_label_;
    248   Label check_preempt_label_;
    249   Label stack_overflow_label_;
    250 };
    251 
    252 #endif  // V8_INTERPRETED_REGEXP
    253 
    254 
    255 }}  // namespace v8::internal
    256 
    257 #endif  // V8_ARM_REGEXP_MACRO_ASSEMBLER_ARM_H_
    258