DXR is a code search and navigation tool aimed at making sense of large projects. It supports full-text and regex searches as well as structural queries.

Implementation

Mercurial (fddffdeab170)

VCS Links

Line Code
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 * vim: set ts=8 sts=4 et sw=4 tw=99: */

// Copyright 2012 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
//       notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above
//       copyright notice, this list of conditions and the following
//       disclaimer in the documentation and/or other materials provided
//       with the distribution.
//     * Neither the name of Google Inc. nor the names of its
//       contributors may be used to endorse or promote products derived
//       from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#ifndef V8_NATIVE_REGEXP_MACRO_ASSEMBLER_H_
#define V8_NATIVE_REGEXP_MACRO_ASSEMBLER_H_

#include "irregexp/RegExpMacroAssembler.h"

namespace js {
namespace irregexp {

struct InputOutputData
{
    const void* inputStart;
    const void* inputEnd;

    // Index into inputStart (in chars) at which to begin matching.
    size_t startIndex;

    MatchPairs* matches;

    // RegExpMacroAssembler::Result for non-global regexps, number of captures
    // for global regexps.
    int32_t result;

    template <typename CharT>
    InputOutputData(const CharT* inputStart, const CharT* inputEnd,
                    size_t startIndex, MatchPairs* matches)
      : inputStart(inputStart),
        inputEnd(inputEnd),
        startIndex(startIndex),
        matches(matches),
        result(0)
    {}
};

struct FrameData
{
    // Copy of the input/output data's data.
    char16_t* inputStart;
    size_t startIndex;

    // Pointer to the character before the input start.
    char16_t* inputStartMinusOne;

    // Copy of the input MatchPairs registers, may be modified by JIT code.
    int32_t* outputRegisters;
    int32_t numOutputRegisters;

    int32_t successfulCaptures;

    void* backtrackStackBase;
};

class MOZ_STACK_CLASS NativeRegExpMacroAssembler : public RegExpMacroAssembler
{
  public:
    // Type of input string to generate code for.
    enum Mode { ASCII = 1, CHAR16 = 2 };

    NativeRegExpMacroAssembler(LifoAlloc* alloc, RegExpShared* shared,
                               JSRuntime* rt, Mode mode, int registers_to_save);

    // Inherited virtual methods.
    RegExpCode GenerateCode(JSContext* cx, bool match_only);
    int stack_limit_slack();
    bool CanReadUnaligned();
    void AdvanceCurrentPosition(int by);
    void AdvanceRegister(int reg, int by);
    void Backtrack();
    void Bind(jit::Label* label);
    void CheckAtStart(jit::Label* on_at_start);
    void CheckCharacter(unsigned c, jit::Label* on_equal);
    void CheckCharacterAfterAnd(unsigned c, unsigned and_with, jit::Label* on_equal);
    void CheckCharacterGT(char16_t limit, jit::Label* on_greater);
    void CheckCharacterLT(char16_t limit, jit::Label* on_less);
    void CheckGreedyLoop(jit::Label* on_tos_equals_current_position);
    void CheckNotAtStart(jit::Label* on_not_at_start);
    void CheckNotBackReference(int start_reg, jit::Label* on_no_match);
    void CheckNotBackReferenceIgnoreCase(int start_reg, jit::Label* on_no_match);
    void CheckNotCharacter(unsigned c, jit::Label* on_not_equal);
    void CheckNotCharacterAfterAnd(unsigned c, unsigned and_with, jit::Label* on_not_equal);
    void CheckNotCharacterAfterMinusAnd(char16_t c, char16_t minus, char16_t and_with,
                                        jit::Label* on_not_equal);
    void CheckCharacterInRange(char16_t from, char16_t to,
                               jit::Label* on_in_range);
    void CheckCharacterNotInRange(char16_t from, char16_t to,
                                  jit::Label* on_not_in_range);
    void CheckBitInTable(uint8_t* table, jit::Label* on_bit_set);
    void CheckPosition(int cp_offset, jit::Label* on_outside_input);
    void JumpOrBacktrack(jit::Label* to);
    bool CheckSpecialCharacterClass(char16_t type, jit::Label* on_no_match);
    void Fail();
    void IfRegisterGE(int reg, int comparand, jit::Label* if_ge);
    void IfRegisterLT(int reg, int comparand, jit::Label* if_lt);
    void IfRegisterEqPos(int reg, jit::Label* if_eq);
    void LoadCurrentCharacter(int cp_offset, jit::Label* on_end_of_input,
                              bool check_bounds = true, int characters = 1);
    void PopCurrentPosition();
    void PopRegister(int register_index);
    void PushCurrentPosition();
    void PushRegister(int register_index, StackCheckFlag check_stack_limit);
    void ReadCurrentPositionFromRegister(int reg);
    void ReadBacktrackStackPointerFromRegister(int reg);
    void SetCurrentPositionFromEnd(int by);
    void SetRegister(int register_index, int to);
    bool Succeed();
    void WriteCurrentPositionToRegister(int reg, int cp_offset);
    void ClearRegisters(int reg_from, int reg_to);
    void WriteBacktrackStackPointerToRegister(int reg);
    void PushBacktrack(jit::Label* label);
    void BindBacktrack(jit::Label* label);

    // Compares two-byte strings case insensitively.
    // Called from generated RegExp code.
    static int CaseInsensitiveCompareUC16(jit::Address byte_offset1,
                                          jit::Address byte_offset2,
                                          size_t byte_length);

    // Byte map of one byte characters with a 0xff if the character is a word
    // character (digit, letter or underscore) and 0x00 otherwise.
    // Used by generated RegExp code.
    static const uint8_t word_character_map[256];

    // Byte size of chars in the string to match (decided by the Mode argument)
    inline int char_size() { return static_cast<int>(mode_); }
    inline jit::Scale factor() { return mode_ == CHAR16 ? jit::TimesTwo : jit::TimesOne; }

    jit::Label* BranchOrBacktrack(jit::Label* branch);

    // Pushes a register or constant on the backtrack stack. Decrements the
    // stack pointer by a word size and stores the register's value there.
    void PushBacktrack(jit::Register value);
    void PushBacktrack(int32_t value);

    // Pop a value from the backtrack stack.
    void PopBacktrack(jit::Register target);

    // Check whether we are exceeding the stack limit on the backtrack stack.
    void CheckBacktrackStackLimit();

    void LoadCurrentCharacterUnchecked(int cp_offset, int characters);

  private:
    jit::MacroAssembler masm;

    JSRuntime* runtime;
    Mode mode_;
    jit::Label entry_label_;
    jit::Label start_label_;
    jit::Label backtrack_label_;
    jit::Label success_label_;
    jit::Label exit_label_;
    jit::Label stack_overflow_label_;
    jit::Label exit_with_exception_label_;

    // Set of registers which are used by the code generator, and as such which
    // are saved.
    jit::LiveGeneralRegisterSet savedNonVolatileRegisters;

    struct LabelPatch {
        // Once it is bound via BindBacktrack, |label| becomes null and
        // |labelOffset| is set.
        jit::Label* label;
        size_t labelOffset;

        jit::CodeOffsetLabel patchOffset;

        LabelPatch(jit::Label* label, jit::CodeOffsetLabel patchOffset)
          : label(label), labelOffset(0), patchOffset(patchOffset)
        {}
    };

    Vector<LabelPatch, 4, SystemAllocPolicy> labelPatches;

    // See RegExpMacroAssembler.cpp for the meaning of these registers.
    jit::Register input_end_pointer;
    jit::Register current_character;
    jit::Register current_position;
    jit::Register backtrack_stack_pointer;
    jit::Register temp0, temp1, temp2;

    // The frame_pointer-relative location of a regexp register.
    jit::Address register_location(int register_index) {
        checkRegister(register_index);
        return jit::Address(masm.getStackPointer(), register_offset(register_index));
    }

    int32_t register_offset(int register_index) {
        return sizeof(FrameData) + register_index * sizeof(void*);
    }
};

} }  // namespace js::irregexp

#endif  // V8_NATIVE_REGEXP_MACRO_ASSEMBLER_H_