1// Copyright 2021 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_RISCV64_REGEXP_MACRO_ASSEMBLER_RISCV64_H_
6#define V8_REGEXP_RISCV64_REGEXP_MACRO_ASSEMBLER_RISCV64_H_
7
8#include "src/base/strings.h"
9#include "src/codegen/macro-assembler.h"
10#include "src/codegen/riscv64/assembler-riscv64.h"
11#include "src/regexp/regexp-macro-assembler.h"
12
13namespace v8 {
14namespace internal {
15
16class V8_EXPORT_PRIVATE RegExpMacroAssemblerRISCV
17    : public NativeRegExpMacroAssembler {
18 public:
19  RegExpMacroAssemblerRISCV(Isolate* isolate, Zone* zone, Mode mode,
20                            int registers_to_save);
21  ~RegExpMacroAssemblerRISCV() override;
22  int stack_limit_slack() override;
23  void AdvanceCurrentPosition(int by) override;
24  void AdvanceRegister(int reg, int by) override;
25  void Backtrack() override;
26  void Bind(Label* label) override;
27  void CheckAtStart(int cp_offset, Label* on_at_start) override;
28  void CheckCharacter(uint32_t c, Label* on_equal) override;
29  void CheckCharacterAfterAnd(uint32_t c, uint32_t mask,
30                              Label* on_equal) override;
31  void CheckCharacterGT(base::uc16 limit, Label* on_greater) override;
32  void CheckCharacterLT(base::uc16 limit, Label* on_less) override;
33  // A "greedy loop" is a loop that is both greedy and with a simple
34  // body. It has a particularly simple implementation.
35  void CheckGreedyLoop(Label* on_tos_equals_current_position) override;
36  void CheckNotAtStart(int cp_offset, Label* on_not_at_start) override;
37  void CheckNotBackReference(int start_reg, bool read_backward,
38                             Label* on_no_match) override;
39  void CheckNotBackReferenceIgnoreCase(int start_reg, bool read_backward,
40                                       bool unicode,
41                                       Label* on_no_match) override;
42  void CheckNotCharacter(uint32_t c, Label* on_not_equal) override;
43  void CheckNotCharacterAfterAnd(uint32_t c, uint32_t mask,
44                                 Label* on_not_equal) override;
45  void CheckNotCharacterAfterMinusAnd(base::uc16 c, base::uc16 minus,
46                                      base::uc16 mask,
47                                      Label* on_not_equal) override;
48  void CheckCharacterInRange(base::uc16 from, base::uc16 to,
49                             Label* on_in_range) override;
50  void CheckCharacterNotInRange(base::uc16 from, base::uc16 to,
51                                Label* on_not_in_range) override;
52  bool CheckCharacterInRangeArray(const ZoneList<CharacterRange>* ranges,
53                                  Label* on_in_range) override;
54  bool CheckCharacterNotInRangeArray(const ZoneList<CharacterRange>* ranges,
55                                     Label* on_not_in_range) override;
56  void CheckBitInTable(Handle<ByteArray> table, Label* on_bit_set) override;
57
58  // Checks whether the given offset from the current position is before
59  // the end of the string.
60  void CheckPosition(int cp_offset, Label* on_outside_input) override;
61  bool CheckSpecialCharacterClass(StandardCharacterSet type,
62                                  Label* on_no_match) override;
63  void Fail() override;
64  Handle<HeapObject> GetCode(Handle<String> source) override;
65  void GoTo(Label* label) override;
66  void IfRegisterGE(int reg, int comparand, Label* if_ge) override;
67  void IfRegisterLT(int reg, int comparand, Label* if_lt) override;
68  void IfRegisterEqPos(int reg, Label* if_eq) override;
69  IrregexpImplementation Implementation() override;
70  void LoadCurrentCharacterUnchecked(int cp_offset,
71                                     int character_count) override;
72  void PopCurrentPosition() override;
73  void PopRegister(int register_index) override;
74  void PushBacktrack(Label* label) override;
75  void PushCurrentPosition() override;
76  void PushRegister(int register_index,
77                    StackCheckFlag check_stack_limit) override;
78  void ReadCurrentPositionFromRegister(int reg) override;
79  void ReadStackPointerFromRegister(int reg) override;
80  void SetCurrentPositionFromEnd(int by) override;
81  void SetRegister(int register_index, int to) override;
82  bool Succeed() override;
83  void WriteCurrentPositionToRegister(int reg, int cp_offset) override;
84  void ClearRegisters(int reg_from, int reg_to) override;
85  void WriteStackPointerToRegister(int reg) override;
86#ifdef RISCV_HAS_NO_UNALIGNED
87  bool CanReadUnaligned() const override;
88#endif
89  // Called from RegExp if the stack-guard is triggered.
90  // If the code object is relocated, the return address is fixed before
91  // returning.
92  // {raw_code} is an Address because this is called via ExternalReference.
93  static int64_t CheckStackGuardState(Address* return_address, Address raw_code,
94                                      Address re_frame);
95
96  void print_regexp_frame_constants();
97
98 private:
99  // Offsets from frame_pointer() of function parameters and stored registers.
100  static const int kFramePointer = 0;
101
102  // Above the frame pointer - Stored registers and stack passed parameters.
103  // Registers s1 to s8, fp, and ra.
104  static const int kStoredRegisters = kFramePointer;
105  // Return address (stored from link register, read into pc on return).
106
107  // This 9 is 8 s-regs (s1..s8) plus fp.
108  static const int kNumCalleeRegsToRetain = 9;
109  static const int kReturnAddress =
110      kStoredRegisters + kNumCalleeRegsToRetain * kSystemPointerSize;
111
112  // Stack frame header.
113  static const int kStackFrameHeader = kReturnAddress;
114  // Below the frame pointer.
115  // Register parameters stored by setup code.
116  static const int kIsolate = kFramePointer - kSystemPointerSize;
117  static const int kDirectCall = kIsolate - kSystemPointerSize;
118  static const int kNumOutputRegisters = kDirectCall - kSystemPointerSize;
119  static const int kRegisterOutput = kNumOutputRegisters - kSystemPointerSize;
120  static const int kInputEnd = kRegisterOutput - kSystemPointerSize;
121  static const int kInputStart = kInputEnd - kSystemPointerSize;
122  static const int kStartIndex = kInputStart - kSystemPointerSize;
123  static const int kInputString = kStartIndex - kSystemPointerSize;
124  // When adding local variables remember to push space for them in
125  // the frame in GetCode.
126  static const int kSuccessfulCaptures = kInputString - kSystemPointerSize;
127  static const int kStringStartMinusOne =
128      kSuccessfulCaptures - kSystemPointerSize;
129  static const int kBacktrackCount = kStringStartMinusOne - kSystemPointerSize;
130  // Stores the initial value of the regexp stack pointer in a
131  // position-independent representation (in case the regexp stack grows and
132  // thus moves).
133  static const int kRegExpStackBasePointer =
134      kBacktrackCount - kSystemPointerSize;
135  static constexpr int kNumberOfStackLocals = 4;
136  // First register address. Following registers are below it on the stack.
137  static const int kRegisterZero = kRegExpStackBasePointer - kSystemPointerSize;
138
139  // Initial size of code buffer.
140  static const int kRegExpCodeSize = 1024;
141
142  void PushCallerSavedRegisters();
143  void PopCallerSavedRegisters();
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  void CallCheckStackGuardState(Register scratch);
152  void CallIsCharacterInRangeArray(const ZoneList<CharacterRange>* ranges);
153
154  // The ebp-relative location of a regexp register.
155  MemOperand register_location(int register_index);
156
157  // Register holding the current input position as negative offset from
158  // the end of the string.
159  static constexpr Register current_input_offset() { return s1; }
160
161  // The register containing the current character after LoadCurrentCharacter.
162  static constexpr Register current_character() { return s2; }
163
164  // Register holding address of the end of the input string.
165  static constexpr Register end_of_input_address() { return t2; }
166
167  // Register holding the frame address. Local variables, parameters and
168  // regexp registers are addressed relative to this.
169  static constexpr Register frame_pointer() { return fp; }
170
171  // The register containing the backtrack stack top. Provides a meaningful
172  // name to the register.
173  static constexpr Register backtrack_stackpointer() { return t0; }
174
175  // Register holding pointer to the current code object.
176  static constexpr Register code_pointer() { return s4; }
177
178  // Byte size of chars in the string to match (decided by the Mode argument).
179  inline int char_size() const { return static_cast<int>(mode_); }
180
181  // Equivalent to a conditional branch to the label, unless the label
182  // is nullptr, in which case it is a conditional Backtrack.
183  void BranchOrBacktrack(Label* to, Condition condition, Register rs,
184                         const Operand& rt);
185
186  // Call and return internally in the generated code in a way that
187  // is GC-safe (i.e., doesn't leave absolute code addresses on the stack)
188  inline void SafeCall(Label* to, Condition cond, Register rs,
189                       const Operand& rt);
190  inline void SafeReturn();
191  inline void SafeCallTarget(Label* name);
192
193  // Pushes the value of a register on the backtrack stack. Decrements the
194  // stack pointer by a word size and stores the register's value there.
195  inline void Push(Register source);
196
197  // Pops a value from the backtrack stack. Reads the word at the stack pointer
198  // and increments it by a word size.
199  inline void Pop(Register target);
200
201  void LoadRegExpStackPointerFromMemory(Register dst);
202  void StoreRegExpStackPointerToMemory(Register src, Register scratch);
203  void PushRegExpBasePointer(Register scratch1, Register scratch2);
204  void PopRegExpBasePointer(Register scratch1, Register scratch2);
205
206  Isolate* isolate() const { return masm_->isolate(); }
207
208  const std::unique_ptr<MacroAssembler> masm_;
209  const NoRootArrayScope no_root_array_scope_;
210
211  // Which mode to generate code for (Latin1 or UC16).
212  const Mode mode_;
213
214  // One greater than maximal register index actually used.
215  int num_registers_;
216
217  // Number of registers to output at the end (the saved registers
218  // are always 0..num_saved_registers_-1).
219  const int num_saved_registers_;
220
221  // Labels used internally.
222  Label entry_label_;
223  Label start_label_;
224  Label success_label_;
225  Label backtrack_label_;
226  Label exit_label_;
227  Label check_preempt_label_;
228  Label stack_overflow_label_;
229  Label internal_failure_label_;
230  Label fallback_label_;
231};
232
233}  // namespace internal
234}  // namespace v8
235
236#endif  // V8_REGEXP_RISCV64_REGEXP_MACRO_ASSEMBLER_RISCV64_H_
237