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_ARM64_REGEXP_MACRO_ASSEMBLER_ARM64_H_
6 #define V8_ARM64_REGEXP_MACRO_ASSEMBLER_ARM64_H_
7 
8 #include "src/macro-assembler.h"
9 
10 #include "src/arm64/assembler-arm64.h"
11 #include "src/arm64/assembler-arm64-inl.h"
12 
13 namespace v8 {
14 namespace internal {
15 
16 
17 #ifndef V8_INTERPRETED_REGEXP
18 class RegExpMacroAssemblerARM64: public NativeRegExpMacroAssembler {
19  public:
20   RegExpMacroAssemblerARM64(Mode mode, int registers_to_save, Zone* zone);
21   virtual ~RegExpMacroAssemblerARM64();
22   virtual int stack_limit_slack();
23   virtual void AdvanceCurrentPosition(int by);
24   virtual void AdvanceRegister(int reg, int by);
25   virtual void Backtrack();
26   virtual void Bind(Label* label);
27   virtual void CheckAtStart(Label* on_at_start);
28   virtual void CheckCharacter(unsigned c, Label* on_equal);
29   virtual void CheckCharacterAfterAnd(unsigned c,
30                                       unsigned mask,
31                                       Label* on_equal);
32   virtual void CheckCharacterGT(uc16 limit, Label* on_greater);
33   virtual void CheckCharacterLT(uc16 limit, Label* on_less);
34   virtual void CheckCharacters(Vector<const uc16> str,
35                                int cp_offset,
36                                Label* on_failure,
37                                bool check_end_of_string);
38   // A "greedy loop" is a loop that is both greedy and with a simple
39   // body. It has a particularly simple implementation.
40   virtual void CheckGreedyLoop(Label* on_tos_equals_current_position);
41   virtual void CheckNotAtStart(Label* on_not_at_start);
42   virtual void CheckNotBackReference(int start_reg, Label* on_no_match);
43   virtual void CheckNotBackReferenceIgnoreCase(int start_reg,
44                                                Label* on_no_match);
45   virtual void CheckNotCharacter(unsigned c, Label* on_not_equal);
46   virtual void CheckNotCharacterAfterAnd(unsigned c,
47                                          unsigned mask,
48                                          Label* on_not_equal);
49   virtual void CheckNotCharacterAfterMinusAnd(uc16 c,
50                                               uc16 minus,
51                                               uc16 mask,
52                                               Label* on_not_equal);
53   virtual void CheckCharacterInRange(uc16 from,
54                                      uc16 to,
55                                      Label* on_in_range);
56   virtual void CheckCharacterNotInRange(uc16 from,
57                                         uc16 to,
58                                         Label* on_not_in_range);
59   virtual void CheckBitInTable(Handle<ByteArray> table, Label* on_bit_set);
60 
61   // Checks whether the given offset from the current position is before
62   // the end of the string.
63   virtual void CheckPosition(int cp_offset, Label* on_outside_input);
64   virtual bool CheckSpecialCharacterClass(uc16 type,
65                                           Label* on_no_match);
66   virtual void Fail();
67   virtual Handle<HeapObject> GetCode(Handle<String> source);
68   virtual void GoTo(Label* label);
69   virtual void IfRegisterGE(int reg, int comparand, Label* if_ge);
70   virtual void IfRegisterLT(int reg, int comparand, Label* if_lt);
71   virtual void IfRegisterEqPos(int reg, Label* if_eq);
72   virtual IrregexpImplementation Implementation();
73   virtual void LoadCurrentCharacter(int cp_offset,
74                                     Label* on_end_of_input,
75                                     bool check_bounds = true,
76                                     int characters = 1);
77   virtual void PopCurrentPosition();
78   virtual void PopRegister(int register_index);
79   virtual void PushBacktrack(Label* label);
80   virtual void PushCurrentPosition();
81   virtual void PushRegister(int register_index,
82                             StackCheckFlag check_stack_limit);
83   virtual void ReadCurrentPositionFromRegister(int reg);
84   virtual void ReadStackPointerFromRegister(int reg);
85   virtual void SetCurrentPositionFromEnd(int by);
86   virtual void SetRegister(int register_index, int to);
87   virtual bool Succeed();
88   virtual void WriteCurrentPositionToRegister(int reg, int cp_offset);
89   virtual void ClearRegisters(int reg_from, int reg_to);
90   virtual void WriteStackPointerToRegister(int reg);
91   virtual bool CanReadUnaligned();
92 
93   // Called from RegExp if the stack-guard is triggered.
94   // If the code object is relocated, the return address is fixed before
95   // returning.
96   static int CheckStackGuardState(Address* return_address,
97                                   Code* re_code,
98                                   Address re_frame,
99                                   int start_offset,
100                                   const byte** input_start,
101                                   const byte** input_end);
102 
103  private:
104   // Above the frame pointer - Stored registers and stack passed parameters.
105   // Callee-saved registers x19-x29, where x29 is the old frame pointer.
106   static const int kCalleeSavedRegisters = 0;
107   // Return address.
108   // It is placed above the 11 callee-saved registers.
109   static const int kReturnAddress = kCalleeSavedRegisters + 11 * kPointerSize;
110   static const int kSecondaryReturnAddress = kReturnAddress + kPointerSize;
111   // Stack parameter placed by caller.
112   static const int kIsolate = kSecondaryReturnAddress + kPointerSize;
113 
114   // Below the frame pointer.
115   // Register parameters stored by setup code.
116   static const int kDirectCall = kCalleeSavedRegisters - kPointerSize;
117   static const int kStackBase = kDirectCall - kPointerSize;
118   static const int kOutputSize = kStackBase - kPointerSize;
119   static const int kInput = kOutputSize - kPointerSize;
120   // When adding local variables remember to push space for them in
121   // the frame in GetCode.
122   static const int kSuccessCounter = kInput - kPointerSize;
123   // First position register address on the stack. Following positions are
124   // below it. A position is a 32 bit value.
125   static const int kFirstRegisterOnStack = kSuccessCounter - kWRegSize;
126   // A capture is a 64 bit value holding two position.
127   static const int kFirstCaptureOnStack = kSuccessCounter - kXRegSize;
128 
129   // Initial size of code buffer.
130   static const size_t kRegExpCodeSize = 1024;
131 
132   // When initializing registers to a non-position value we can unroll
133   // the loop. Set the limit of registers to unroll.
134   static const int kNumRegistersToUnroll = 16;
135 
136   // We are using x0 to x7 as a register cache. Each hardware register must
137   // contain one capture, that is two 32 bit registers. We can cache at most
138   // 16 registers.
139   static const int kNumCachedRegisters = 16;
140 
141   // Load a number of characters at the given offset from the
142   // current position, into the current-character register.
143   void LoadCurrentCharacterUnchecked(int cp_offset, int character_count);
144 
145   // Check whether preemption has been requested.
146   void CheckPreemption();
147 
148   // Check whether we are exceeding the stack limit on the backtrack stack.
149   void CheckStackLimit();
150 
151   // Generate a call to CheckStackGuardState.
152   void CallCheckStackGuardState(Register scratch);
153 
154   // Location of a 32 bit position register.
155   MemOperand register_location(int register_index);
156 
157   // Location of a 64 bit capture, combining two position registers.
158   MemOperand capture_location(int register_index, Register scratch);
159 
160   // Register holding the current input position as negative offset from
161   // the end of the string.
current_input_offset()162   Register current_input_offset() { return w21; }
163 
164   // The register containing the current character after LoadCurrentCharacter.
current_character()165   Register current_character() { return w22; }
166 
167   // Register holding address of the end of the input string.
input_end()168   Register input_end() { return x25; }
169 
170   // Register holding address of the start of the input string.
input_start()171   Register input_start() { return x26; }
172 
173   // Register holding the offset from the start of the string where we should
174   // start matching.
start_offset()175   Register start_offset() { return w27; }
176 
177   // Pointer to the output array's first element.
output_array()178   Register output_array() { return x28; }
179 
180   // Register holding the frame address. Local variables, parameters and
181   // regexp registers are addressed relative to this.
frame_pointer()182   Register frame_pointer() { return fp; }
183 
184   // The register containing the backtrack stack top. Provides a meaningful
185   // name to the register.
backtrack_stackpointer()186   Register backtrack_stackpointer() { return x23; }
187 
188   // Register holding pointer to the current code object.
code_pointer()189   Register code_pointer() { return x20; }
190 
191   // Register holding the value used for clearing capture registers.
non_position_value()192   Register non_position_value() { return w24; }
193   // The top 32 bit of this register is used to store this value
194   // twice. This is used for clearing more than one register at a time.
twice_non_position_value()195   Register twice_non_position_value() { return x24; }
196 
197   // Byte size of chars in the string to match (decided by the Mode argument)
char_size()198   int char_size() { return static_cast<int>(mode_); }
199 
200   // Equivalent to a conditional branch to the label, unless the label
201   // is NULL, in which case it is a conditional Backtrack.
202   void BranchOrBacktrack(Condition condition, Label* to);
203 
204   // Compares reg against immmediate before calling BranchOrBacktrack.
205   // It makes use of the Cbz and Cbnz instructions.
206   void CompareAndBranchOrBacktrack(Register reg,
207                                    int immediate,
208                                    Condition condition,
209                                    Label* to);
210 
211   inline void CallIf(Label* to, Condition condition);
212 
213   // Save and restore the link register on the stack in a way that
214   // is GC-safe.
215   inline void SaveLinkRegister();
216   inline void RestoreLinkRegister();
217 
218   // Pushes the value of a register on the backtrack stack. Decrements the
219   // stack pointer by a word size and stores the register's value there.
220   inline void Push(Register source);
221 
222   // Pops a value from the backtrack stack. Reads the word at the stack pointer
223   // and increments it by a word size.
224   inline void Pop(Register target);
225 
226   // This state indicates where the register actually is.
227   enum RegisterState {
228     STACKED,     // Resides in memory.
229     CACHED_LSW,  // Least Significant Word of a 64 bit hardware register.
230     CACHED_MSW   // Most Significant Word of a 64 bit hardware register.
231   };
232 
GetRegisterState(int register_index)233   RegisterState GetRegisterState(int register_index) {
234     DCHECK(register_index >= 0);
235     if (register_index >= kNumCachedRegisters) {
236       return STACKED;
237     } else {
238       if ((register_index % 2) == 0) {
239         return CACHED_LSW;
240       } else {
241         return CACHED_MSW;
242       }
243     }
244   }
245 
246   // Store helper that takes the state of the register into account.
247   inline void StoreRegister(int register_index, Register source);
248 
249   // Returns a hardware W register that holds the value of the capture
250   // register.
251   //
252   // This function will try to use an existing cache register (w0-w7) for the
253   // result. Otherwise, it will load the value into maybe_result.
254   //
255   // If the returned register is anything other than maybe_result, calling code
256   // must not write to it.
257   inline Register GetRegister(int register_index, Register maybe_result);
258 
259   // Returns the harware register (x0-x7) holding the value of the capture
260   // register.
261   // This assumes that the state of the register is not STACKED.
262   inline Register GetCachedRegister(int register_index);
263 
isolate()264   Isolate* isolate() const { return masm_->isolate(); }
265 
266   MacroAssembler* masm_;
267 
268   // Which mode to generate code for (LATIN1 or UC16).
269   Mode mode_;
270 
271   // One greater than maximal register index actually used.
272   int num_registers_;
273 
274   // Number of registers to output at the end (the saved registers
275   // are always 0..num_saved_registers_-1)
276   int num_saved_registers_;
277 
278   // Labels used internally.
279   Label entry_label_;
280   Label start_label_;
281   Label success_label_;
282   Label backtrack_label_;
283   Label exit_label_;
284   Label check_preempt_label_;
285   Label stack_overflow_label_;
286 };
287 
288 #endif  // V8_INTERPRETED_REGEXP
289 
290 
291 }}  // namespace v8::internal
292 
293 #endif  // V8_ARM64_REGEXP_MACRO_ASSEMBLER_ARM64_H_
294