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
10namespace v8 {
11namespace internal {
12
13struct DisjunctDecisionRow {
14  RegExpCharacterClass cc;
15  Label* on_match;
16};
17
18
19class 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
171class 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