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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_REGEXP_MACRO_ASSEMBLER_H_
6 #define V8_REGEXP_REGEXP_MACRO_ASSEMBLER_H_
7 
8 #include "src/assembler.h"
9 #include "src/regexp/regexp-ast.h"
10 
11 namespace v8 {
12 namespace internal {
13 
14 static const uc32 kLeadSurrogateStart = 0xd800;
15 static const uc32 kLeadSurrogateEnd = 0xdbff;
16 static const uc32 kTrailSurrogateStart = 0xdc00;
17 static const uc32 kTrailSurrogateEnd = 0xdfff;
18 static const uc32 kNonBmpStart = 0x10000;
19 static const uc32 kNonBmpEnd = 0x10ffff;
20 
21 struct DisjunctDecisionRow {
22   RegExpCharacterClass cc;
23   Label* on_match;
24 };
25 
26 
27 class RegExpMacroAssembler {
28  public:
29   // The implementation must be able to handle at least:
30   static const int kMaxRegister = (1 << 16) - 1;
31   static const int kMaxCPOffset = (1 << 15) - 1;
32   static const int kMinCPOffset = -(1 << 15);
33 
34   static const int kTableSizeBits = 7;
35   static const int kTableSize = 1 << kTableSizeBits;
36   static const int kTableMask = kTableSize - 1;
37 
38   enum IrregexpImplementation {
39     kIA32Implementation,
40     kARMImplementation,
41     kARM64Implementation,
42     kMIPSImplementation,
43     kS390Implementation,
44     kPPCImplementation,
45     kX64Implementation,
46     kX87Implementation,
47     kBytecodeImplementation
48   };
49 
50   enum StackCheckFlag {
51     kNoStackLimitCheck = false,
52     kCheckStackLimit = true
53   };
54 
55   RegExpMacroAssembler(Isolate* isolate, Zone* zone);
56   virtual ~RegExpMacroAssembler();
57   // This function is called when code generation is aborted, so that
58   // the assembler could clean up internal data structures.
AbortedCodeGeneration()59   virtual void AbortedCodeGeneration() {}
60   // The maximal number of pushes between stack checks. Users must supply
61   // kCheckStackLimit flag to push operations (instead of kNoStackLimitCheck)
62   // at least once for every stack_limit() pushes that are executed.
63   virtual int stack_limit_slack() = 0;
64   virtual bool CanReadUnaligned() = 0;
65   virtual void AdvanceCurrentPosition(int by) = 0;  // Signed cp change.
66   virtual void AdvanceRegister(int reg, int by) = 0;  // r[reg] += by.
67   // Continues execution from the position pushed on the top of the backtrack
68   // stack by an earlier PushBacktrack(Label*).
69   virtual void Backtrack() = 0;
70   virtual void Bind(Label* label) = 0;
71   virtual void CheckAtStart(Label* on_at_start) = 0;
72   // Dispatch after looking the current character up in a 2-bits-per-entry
73   // map.  The destinations vector has up to 4 labels.
74   virtual void CheckCharacter(unsigned c, Label* on_equal) = 0;
75   // Bitwise and the current character with the given constant and then
76   // check for a match with c.
77   virtual void CheckCharacterAfterAnd(unsigned c,
78                                       unsigned and_with,
79                                       Label* on_equal) = 0;
80   virtual void CheckCharacterGT(uc16 limit, Label* on_greater) = 0;
81   virtual void CheckCharacterLT(uc16 limit, Label* on_less) = 0;
82   virtual void CheckGreedyLoop(Label* on_tos_equals_current_position) = 0;
83   virtual void CheckNotAtStart(int cp_offset, Label* on_not_at_start) = 0;
84   virtual void CheckNotBackReference(int start_reg, bool read_backward,
85                                      Label* on_no_match) = 0;
86   virtual void CheckNotBackReferenceIgnoreCase(int start_reg,
87                                                bool read_backward, bool unicode,
88                                                Label* on_no_match) = 0;
89   // Check the current character for a match with a literal character.  If we
90   // fail to match then goto the on_failure label.  End of input always
91   // matches.  If the label is NULL then we should pop a backtrack address off
92   // the stack and go to that.
93   virtual void CheckNotCharacter(unsigned c, Label* on_not_equal) = 0;
94   virtual void CheckNotCharacterAfterAnd(unsigned c,
95                                          unsigned and_with,
96                                          Label* on_not_equal) = 0;
97   // Subtract a constant from the current character, then and with the given
98   // constant and then check for a match with c.
99   virtual void CheckNotCharacterAfterMinusAnd(uc16 c,
100                                               uc16 minus,
101                                               uc16 and_with,
102                                               Label* on_not_equal) = 0;
103   virtual void CheckCharacterInRange(uc16 from,
104                                      uc16 to,  // Both inclusive.
105                                      Label* on_in_range) = 0;
106   virtual void CheckCharacterNotInRange(uc16 from,
107                                         uc16 to,  // Both inclusive.
108                                         Label* on_not_in_range) = 0;
109 
110   // The current character (modulus the kTableSize) is looked up in the byte
111   // array, and if the found byte is non-zero, we jump to the on_bit_set label.
112   virtual void CheckBitInTable(Handle<ByteArray> table, Label* on_bit_set) = 0;
113 
114   // Checks whether the given offset from the current position is before
115   // the end of the string.  May overwrite the current character.
116   virtual void CheckPosition(int cp_offset, Label* on_outside_input);
117   // Check whether a standard/default character class matches the current
118   // character. Returns false if the type of special character class does
119   // not have custom support.
120   // May clobber the current loaded character.
121   virtual bool CheckSpecialCharacterClass(uc16 type, Label* on_no_match);
122   virtual void Fail() = 0;
123   virtual Handle<HeapObject> GetCode(Handle<String> source) = 0;
124   virtual void GoTo(Label* label) = 0;
125   // Check whether a register is >= a given constant and go to a label if it
126   // is.  Backtracks instead if the label is NULL.
127   virtual void IfRegisterGE(int reg, int comparand, Label* if_ge) = 0;
128   // Check whether a register is < a given constant and go to a label if it is.
129   // Backtracks instead if the label is NULL.
130   virtual void IfRegisterLT(int reg, int comparand, Label* if_lt) = 0;
131   // Check whether a register is == to the current position and go to a
132   // label if it is.
133   virtual void IfRegisterEqPos(int reg, Label* if_eq) = 0;
134   virtual IrregexpImplementation Implementation() = 0;
135   virtual void LoadCurrentCharacter(int cp_offset,
136                                     Label* on_end_of_input,
137                                     bool check_bounds = true,
138                                     int characters = 1) = 0;
139   virtual void PopCurrentPosition() = 0;
140   virtual void PopRegister(int register_index) = 0;
141   // Pushes the label on the backtrack stack, so that a following Backtrack
142   // will go to this label. Always checks the backtrack stack limit.
143   virtual void PushBacktrack(Label* label) = 0;
144   virtual void PushCurrentPosition() = 0;
145   virtual void PushRegister(int register_index,
146                             StackCheckFlag check_stack_limit) = 0;
147   virtual void ReadCurrentPositionFromRegister(int reg) = 0;
148   virtual void ReadStackPointerFromRegister(int reg) = 0;
149   virtual void SetCurrentPositionFromEnd(int by) = 0;
150   virtual void SetRegister(int register_index, int to) = 0;
151   // Return whether the matching (with a global regexp) will be restarted.
152   virtual bool Succeed() = 0;
153   virtual void WriteCurrentPositionToRegister(int reg, int cp_offset) = 0;
154   virtual void ClearRegisters(int reg_from, int reg_to) = 0;
155   virtual void WriteStackPointerToRegister(int reg) = 0;
156 
157   // Compares two-byte strings case insensitively.
158   // Called from generated RegExp code.
159   static int CaseInsensitiveCompareUC16(Address byte_offset1,
160                                         Address byte_offset2,
161                                         size_t byte_length, Isolate* isolate);
162 
163   // Check that we are not in the middle of a surrogate pair.
164   void CheckNotInSurrogatePair(int cp_offset, Label* on_failure);
165 
166   // Controls the generation of large inlined constants in the code.
set_slow_safe(bool ssc)167   void set_slow_safe(bool ssc) { slow_safe_compiler_ = ssc; }
slow_safe()168   bool slow_safe() { return slow_safe_compiler_; }
169 
170   enum GlobalMode {
171     NOT_GLOBAL,
172     GLOBAL_NO_ZERO_LENGTH_CHECK,
173     GLOBAL,
174     GLOBAL_UNICODE
175   };
176   // Set whether the regular expression has the global flag.  Exiting due to
177   // a failure in a global regexp may still mean success overall.
set_global_mode(GlobalMode mode)178   inline void set_global_mode(GlobalMode mode) { global_mode_ = mode; }
global()179   inline bool global() { return global_mode_ != NOT_GLOBAL; }
global_with_zero_length_check()180   inline bool global_with_zero_length_check() {
181     return global_mode_ == GLOBAL || global_mode_ == GLOBAL_UNICODE;
182   }
global_unicode()183   inline bool global_unicode() { return global_mode_ == GLOBAL_UNICODE; }
184 
isolate()185   Isolate* isolate() const { return isolate_; }
zone()186   Zone* zone() const { return zone_; }
187 
188  private:
189   bool slow_safe_compiler_;
190   GlobalMode global_mode_;
191   Isolate* isolate_;
192   Zone* zone_;
193 };
194 
195 
196 #ifndef V8_INTERPRETED_REGEXP  // Avoid compiling unused code.
197 
198 class NativeRegExpMacroAssembler: public RegExpMacroAssembler {
199  public:
200   // Type of input string to generate code for.
201   enum Mode { LATIN1 = 1, UC16 = 2 };
202 
203   // Result of calling generated native RegExp code.
204   // RETRY: Something significant changed during execution, and the matching
205   //        should be retried from scratch.
206   // EXCEPTION: Something failed during execution. If no exception has been
207   //        thrown, it's an internal out-of-memory, and the caller should
208   //        throw the exception.
209   // FAILURE: Matching failed.
210   // SUCCESS: Matching succeeded, and the output array has been filled with
211   //        capture positions.
212   enum Result { RETRY = -2, EXCEPTION = -1, FAILURE = 0, SUCCESS = 1 };
213 
214   NativeRegExpMacroAssembler(Isolate* isolate, Zone* zone);
215   virtual ~NativeRegExpMacroAssembler();
216   virtual bool CanReadUnaligned();
217 
218   static Result Match(Handle<Code> regexp,
219                       Handle<String> subject,
220                       int* offsets_vector,
221                       int offsets_vector_length,
222                       int previous_index,
223                       Isolate* isolate);
224 
225   // Called from RegExp if the backtrack stack limit is hit.
226   // Tries to expand the stack. Returns the new stack-pointer if
227   // successful, and updates the stack_top address, or returns 0 if unable
228   // to grow the stack.
229   // This function must not trigger a garbage collection.
230   static Address GrowStack(Address stack_pointer, Address* stack_top,
231                            Isolate* isolate);
232 
233   static const byte* StringCharacterPosition(String* subject, int start_index);
234 
235   static int CheckStackGuardState(Isolate* isolate, int start_index,
236                                   bool is_direct_call, Address* return_address,
237                                   Code* re_code, String** subject,
238                                   const byte** input_start,
239                                   const byte** input_end);
240 
241   // Byte map of one byte characters with a 0xff if the character is a word
242   // character (digit, letter or underscore) and 0x00 otherwise.
243   // Used by generated RegExp code.
244   static const byte word_character_map[256];
245 
word_character_map_address()246   static Address word_character_map_address() {
247     return const_cast<Address>(&word_character_map[0]);
248   }
249 
250   static Result Execute(Code* code,
251                         String* input,
252                         int start_offset,
253                         const byte* input_start,
254                         const byte* input_end,
255                         int* output,
256                         int output_size,
257                         Isolate* isolate);
258 };
259 
260 #endif  // V8_INTERPRETED_REGEXP
261 
262 }  // namespace internal
263 }  // namespace v8
264 
265 #endif  // V8_REGEXP_REGEXP_MACRO_ASSEMBLER_H_
266