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// Copyright 2011 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// A simple interpreter for the Irregexp byte code.
#include "src/regexp/regexp-interpreter.h"
#include "src/ast/ast.h"
#include "src/base/small-vector.h"
#include "src/objects/js-regexp-inl.h"
#include "src/objects/objects-inl.h"
#include "src/regexp/regexp-bytecodes.h"
#include "src/regexp/regexp-macro-assembler.h"
#include "src/regexp/regexp.h"
#include "src/strings/unicode.h"
#include "src/utils/utils.h"
#ifdef V8_INTL_SUPPORT
#include "unicode/uchar.h"
#endif // V8_INTL_SUPPORT
// Use token threaded dispatch iff the compiler supports computed gotos and the
// build argument v8_enable_regexp_interpreter_threaded_dispatch was set.
#if V8_HAS_COMPUTED_GOTO && \
defined(V8_ENABLE_REGEXP_INTERPRETER_THREADED_DISPATCH)
#define V8_USE_COMPUTED_GOTO 1
#endif // V8_HAS_COMPUTED_GOTO
namespace v8 {
namespace internal {
namespace {
bool BackRefMatchesNoCase(Isolate* isolate, int from, int current, int len,
Vector<const uc16> subject, bool unicode) {
Address offset_a =
reinterpret_cast<Address>(const_cast<uc16*>(&subject.at(from)));
Address offset_b =
reinterpret_cast<Address>(const_cast<uc16*>(&subject.at(current)));
size_t length = len * kUC16Size;
return RegExpMacroAssembler::CaseInsensitiveCompareUC16(
offset_a, offset_b, length, unicode ? nullptr : isolate) == 1;
}
bool BackRefMatchesNoCase(Isolate* isolate, int from, int current, int len,
Vector<const uint8_t> subject, bool unicode) {
// For Latin1 characters the unicode flag makes no difference.
for (int i = 0; i < len; i++) {
unsigned int old_char = subject[from++];
unsigned int new_char = subject[current++];
if (old_char == new_char) continue;
// Convert both characters to lower case.
old_char |= 0x20;
new_char |= 0x20;
if (old_char != new_char) return false;
// Not letters in the ASCII range and Latin-1 range.
if (!(old_char - 'a' <= 'z' - 'a') &&
!(old_char - 224 <= 254 - 224 && old_char != 247)) {
return false;
}
}
return true;
}
void DisassembleSingleBytecode(const byte* code_base, const byte* pc) {
PrintF("%s", RegExpBytecodeName(*pc));
// Args and the bytecode as hex.
for (int i = 0; i < RegExpBytecodeLength(*pc); i++) {
PrintF(", %02x", pc[i]);
}
PrintF(" ");
// Args as ascii.
for (int i = 1; i < RegExpBytecodeLength(*pc); i++) {
unsigned char b = pc[i];
PrintF("%c", std::isprint(b) ? b : '.');
}
PrintF("\n");
}
#ifdef DEBUG
void MaybeTraceInterpreter(const byte* code_base, const byte* pc,
int stack_depth, int current_position,
uint32_t current_char, int bytecode_length,
const char* bytecode_name) {
if (FLAG_trace_regexp_bytecodes) {
const bool printable = std::isprint(current_char);
const char* format =
printable
? "pc = %02x, sp = %d, curpos = %d, curchar = %08x (%c), bc = "
: "pc = %02x, sp = %d, curpos = %d, curchar = %08x .%c., bc = ";
PrintF(format, pc - code_base, stack_depth, current_position, current_char,
printable ? current_char : '.');
DisassembleSingleBytecode(code_base, pc);
}
}
#endif // DEBUG
int32_t Load32Aligned(const byte* pc) {
DCHECK_EQ(0, reinterpret_cast<intptr_t>(pc) & 3);
return *reinterpret_cast<const int32_t*>(pc);
}
int32_t Load16Aligned(const byte* pc) {
DCHECK_EQ(0, reinterpret_cast<intptr_t>(pc) & 1);
return *reinterpret_cast<const uint16_t*>(pc);
}
// A simple abstraction over the backtracking stack used by the interpreter.
//
// Despite the name 'backtracking' stack, it's actually used as a generic stack
// that stores both program counters (= offsets into the bytecode) and generic
// integer values.
class BacktrackStack {
public:
BacktrackStack() = default;
void push(int v) { data_.emplace_back(v); }
int peek() const {
DCHECK(!data_.empty());
return data_.back();
}
int pop() {
int v = peek();
data_.pop_back();
return v;
}
// The 'sp' is the index of the first empty element in the stack.
int sp() const { return static_cast<int>(data_.size()); }
void set_sp(int new_sp) {
DCHECK_LE(new_sp, sp());
data_.resize_no_init(new_sp);
}
private:
// Semi-arbitrary. Should be large enough for common cases to remain in the
// static stack-allocated backing store, but small enough not to waste space.
static constexpr int kStaticCapacity = 64;
base::SmallVector<int, kStaticCapacity> data_;
DISALLOW_COPY_AND_ASSIGN(BacktrackStack);
};
IrregexpInterpreter::Result StackOverflow(Isolate* isolate,
RegExp::CallOrigin call_origin) {
CHECK(call_origin == RegExp::CallOrigin::kFromRuntime);
// We abort interpreter execution after the stack overflow is thrown, and thus
// allow allocation here despite the outer DisallowHeapAllocationScope.
AllowHeapAllocation yes_gc;
isolate->StackOverflow();
return IrregexpInterpreter::EXCEPTION;
}
template <typename Char>
void UpdateCodeAndSubjectReferences(
Isolate* isolate, Handle<ByteArray> code_array,
Handle<String> subject_string, ByteArray* code_array_out,
const byte** code_base_out, const byte** pc_out, String* subject_string_out,
Vector<const Char>* subject_string_vector_out) {
DisallowHeapAllocation no_gc;
if (*code_base_out != code_array->GetDataStartAddress()) {
*code_array_out = *code_array;
const intptr_t pc_offset = *pc_out - *code_base_out;
DCHECK_GT(pc_offset, 0);
*code_base_out = code_array->GetDataStartAddress();
*pc_out = *code_base_out + pc_offset;
}
DCHECK(subject_string->IsFlat());
*subject_string_out = *subject_string;
*subject_string_vector_out = subject_string->GetCharVector<Char>(no_gc);
}
// Runs all pending interrupts and updates unhandlified object references if
// necessary.
template <typename Char>
IrregexpInterpreter::Result HandleInterrupts(
Isolate* isolate, RegExp::CallOrigin call_origin, ByteArray* code_array_out,
String* subject_string_out, const byte** code_base_out,
Vector<const Char>* subject_string_vector_out, const byte** pc_out) {
DisallowHeapAllocation no_gc;
StackLimitCheck check(isolate);
bool js_has_overflowed = check.JsHasOverflowed();
if (call_origin == RegExp::CallOrigin::kFromJs) {
// Direct calls from JavaScript can be interrupted in two ways:
// 1. A real stack overflow, in which case we let the caller throw the
// exception.
// 2. The stack guard was used to interrupt execution for another purpose,
// forcing the call through the runtime system.
if (js_has_overflowed) {
return IrregexpInterpreter::EXCEPTION;
} else if (check.InterruptRequested()) {
return IrregexpInterpreter::RETRY;
}
} else {
DCHECK(call_origin == RegExp::CallOrigin::kFromRuntime);
// Prepare for possible GC.
HandleScope handles(isolate);
Handle<ByteArray> code_handle(*code_array_out, isolate);
Handle<String> subject_handle(*subject_string_out, isolate);
if (js_has_overflowed) {
return StackOverflow(isolate, call_origin);
} else if (check.InterruptRequested()) {
const bool was_one_byte =
String::IsOneByteRepresentationUnderneath(*subject_string_out);
Object result;
{
AllowHeapAllocation yes_gc;
result = isolate->stack_guard()->HandleInterrupts();
}
if (result.IsException(isolate)) {
return IrregexpInterpreter::EXCEPTION;
}
// If we changed between a LATIN1 and a UC16 string, we need to restart
// regexp matching with the appropriate template instantiation of
// RawMatch.
if (String::IsOneByteRepresentationUnderneath(*subject_handle) !=
was_one_byte) {
return IrregexpInterpreter::RETRY;
}
UpdateCodeAndSubjectReferences(
isolate, code_handle, subject_handle, code_array_out, code_base_out,
pc_out, subject_string_out, subject_string_vector_out);
}
}
return IrregexpInterpreter::SUCCESS;
}
// If computed gotos are supported by the compiler, we can get addresses to
// labels directly in C/C++. Every bytecode handler has its own label and we
// store the addresses in a dispatch table indexed by bytecode. To execute the
// next handler we simply jump (goto) directly to its address.
#if V8_USE_COMPUTED_GOTO
#define BC_LABEL(name) BC_##name:
#define DECODE() \
do { \
next_insn = Load32Aligned(next_pc); \
next_handler_addr = dispatch_table[next_insn & BYTECODE_MASK]; \
} while (false)
#define DISPATCH() \
pc = next_pc; \
insn = next_insn; \
goto* next_handler_addr
// Without computed goto support, we fall back to a simple switch-based
// dispatch (A large switch statement inside a loop with a case for every
// bytecode).
#else // V8_USE_COMPUTED_GOTO
#define BC_LABEL(name) case BC_##name:
#define DECODE() next_insn = Load32Aligned(next_pc)
#define DISPATCH() \
pc = next_pc; \
insn = next_insn; \
break
#endif // V8_USE_COMPUTED_GOTO
// ADVANCE/SET_PC_FROM_OFFSET are separated from DISPATCH, because ideally some
// instructions can be executed between ADVANCE/SET_PC_FROM_OFFSET and DISPATCH.
// We want those two macros as far apart as possible, because the goto in
// DISPATCH is dependent on a memory load in ADVANCE/SET_PC_FROM_OFFSET. If we
// don't hit the cache and have to fetch the next handler address from physical
// memory, instructions between ADVANCE/SET_PC_FROM_OFFSET and DISPATCH can
// potentially be executed unconditionally, reducing memory stall.
#define ADVANCE(name) \
next_pc = pc + RegExpBytecodeLength(BC_##name); \
DECODE()
#define SET_PC_FROM_OFFSET(offset) \
next_pc = code_base + offset; \
DECODE()
#ifdef DEBUG
#define BYTECODE(name) \
BC_LABEL(name) \
MaybeTraceInterpreter(code_base, pc, backtrack_stack.sp(), current, \
current_char, RegExpBytecodeLength(BC_##name), #name);
#else
#define BYTECODE(name) BC_LABEL(name)
#endif // DEBUG
template <typename Char>
IrregexpInterpreter::Result RawMatch(Isolate* isolate, ByteArray code_array,
String subject_string,
Vector<const Char> subject, int* registers,
int current, uint32_t current_char,
RegExp::CallOrigin call_origin) {
DisallowHeapAllocation no_gc;
#if V8_USE_COMPUTED_GOTO
#define DECLARE_DISPATCH_TABLE_ENTRY(name, code, length) &&BC_##name,
static const void* const dispatch_table[] = {
BYTECODE_ITERATOR(DECLARE_DISPATCH_TABLE_ENTRY)};
#undef DECLARE_DISPATCH_TABLE_ENTRY
#endif
const byte* pc = code_array.GetDataStartAddress();
const byte* code_base = pc;
BacktrackStack backtrack_stack;
#ifdef DEBUG
if (FLAG_trace_regexp_bytecodes) {
PrintF("\n\nStart bytecode interpreter\n\n");
}
#endif
while (true) {
const byte* next_pc = pc;
int32_t insn;
int32_t next_insn;
#if V8_USE_COMPUTED_GOTO
const void* next_handler_addr;
DECODE();
DISPATCH();
#else
insn = Load32Aligned(pc);
switch (insn & BYTECODE_MASK) {
#endif // V8_USE_COMPUTED_GOTO
BYTECODE(BREAK) { UNREACHABLE(); }
BYTECODE(PUSH_CP) {
ADVANCE(PUSH_CP);
backtrack_stack.push(current);
DISPATCH();
}
BYTECODE(PUSH_BT) {
ADVANCE(PUSH_BT);
backtrack_stack.push(Load32Aligned(pc + 4));
DISPATCH();
}
BYTECODE(PUSH_REGISTER) {
ADVANCE(PUSH_REGISTER);
backtrack_stack.push(registers[insn >> BYTECODE_SHIFT]);
DISPATCH();
}
BYTECODE(SET_REGISTER) {
ADVANCE(SET_REGISTER);
registers[insn >> BYTECODE_SHIFT] = Load32Aligned(pc + 4);
DISPATCH();
}
BYTECODE(ADVANCE_REGISTER) {
ADVANCE(ADVANCE_REGISTER);
registers[insn >> BYTECODE_SHIFT] += Load32Aligned(pc + 4);
DISPATCH();
}
BYTECODE(SET_REGISTER_TO_CP) {
ADVANCE(SET_REGISTER_TO_CP);
registers[insn >> BYTECODE_SHIFT] = current + Load32Aligned(pc + 4);
DISPATCH();
}
BYTECODE(SET_CP_TO_REGISTER) {
ADVANCE(SET_CP_TO_REGISTER);
current = registers[insn >> BYTECODE_SHIFT];
DISPATCH();
}
BYTECODE(SET_REGISTER_TO_SP) {
ADVANCE(SET_REGISTER_TO_SP);
registers[insn >> BYTECODE_SHIFT] = backtrack_stack.sp();
DISPATCH();
}
BYTECODE(SET_SP_TO_REGISTER) {
ADVANCE(SET_SP_TO_REGISTER);
backtrack_stack.set_sp(registers[insn >> BYTECODE_SHIFT]);
DISPATCH();
}
BYTECODE(POP_CP) {
ADVANCE(POP_CP);
current = backtrack_stack.pop();
DISPATCH();
}
BYTECODE(POP_BT) {
IrregexpInterpreter::Result return_code =
HandleInterrupts(isolate, call_origin, &code_array, &subject_string,
&code_base, &subject, &pc);
if (return_code != IrregexpInterpreter::SUCCESS) return return_code;
SET_PC_FROM_OFFSET(backtrack_stack.pop());
DISPATCH();
}
BYTECODE(POP_REGISTER) {
ADVANCE(POP_REGISTER);
registers[insn >> BYTECODE_SHIFT] = backtrack_stack.pop();
DISPATCH();
}
BYTECODE(FAIL) { return IrregexpInterpreter::FAILURE; }
BYTECODE(SUCCEED) { return IrregexpInterpreter::SUCCESS; }
BYTECODE(ADVANCE_CP) {
ADVANCE(ADVANCE_CP);
current += insn >> BYTECODE_SHIFT;
DISPATCH();
}
BYTECODE(GOTO) {
SET_PC_FROM_OFFSET(Load32Aligned(pc + 4));
DISPATCH();
}
BYTECODE(ADVANCE_CP_AND_GOTO) {
SET_PC_FROM_OFFSET(Load32Aligned(pc + 4));
current += insn >> BYTECODE_SHIFT;
DISPATCH();
}
BYTECODE(CHECK_GREEDY) {
if (current == backtrack_stack.peek()) {
SET_PC_FROM_OFFSET(Load32Aligned(pc + 4));
backtrack_stack.pop();
} else {
ADVANCE(CHECK_GREEDY);
}
DISPATCH();
}
BYTECODE(LOAD_CURRENT_CHAR) {
int pos = current + (insn >> BYTECODE_SHIFT);
if (pos >= subject.length() || pos < 0) {
SET_PC_FROM_OFFSET(Load32Aligned(pc + 4));
} else {
ADVANCE(LOAD_CURRENT_CHAR);
current_char = subject[pos];
}
DISPATCH();
}
BYTECODE(LOAD_CURRENT_CHAR_UNCHECKED) {
ADVANCE(LOAD_CURRENT_CHAR_UNCHECKED);
int pos = current + (insn >> BYTECODE_SHIFT);
current_char = subject[pos];
DISPATCH();
}
BYTECODE(LOAD_2_CURRENT_CHARS) {
int pos = current + (insn >> BYTECODE_SHIFT);
if (pos + 2 > subject.length() || pos < 0) {
SET_PC_FROM_OFFSET(Load32Aligned(pc + 4));
} else {
ADVANCE(LOAD_2_CURRENT_CHARS);
Char next = subject[pos + 1];
current_char = (subject[pos] | (next << (kBitsPerByte * sizeof(Char))));
}
DISPATCH();
}
BYTECODE(LOAD_2_CURRENT_CHARS_UNCHECKED) {
ADVANCE(LOAD_2_CURRENT_CHARS_UNCHECKED);
int pos = current + (insn >> BYTECODE_SHIFT);
Char next = subject[pos + 1];
current_char = (subject[pos] | (next << (kBitsPerByte * sizeof(Char))));
DISPATCH();
}
BYTECODE(LOAD_4_CURRENT_CHARS) {
DCHECK_EQ(1, sizeof(Char));
int pos = current + (insn >> BYTECODE_SHIFT);
if (pos + 4 > subject.length() || pos < 0) {
SET_PC_FROM_OFFSET(Load32Aligned(pc + 4));
} else {
ADVANCE(LOAD_4_CURRENT_CHARS);
Char next1 = subject[pos + 1];
Char next2 = subject[pos + 2];
Char next3 = subject[pos + 3];
current_char =
(subject[pos] | (next1 << 8) | (next2 << 16) | (next3 << 24));
}
DISPATCH();
}
BYTECODE(LOAD_4_CURRENT_CHARS_UNCHECKED) {
ADVANCE(LOAD_4_CURRENT_CHARS_UNCHECKED);
DCHECK_EQ(1, sizeof(Char));
int pos = current + (insn >> BYTECODE_SHIFT);
Char next1 = subject[pos + 1];
Char next2 = subject[pos + 2];
Char next3 = subject[pos + 3];
current_char =
(subject[pos] | (next1 << 8) | (next2 << 16) | (next3 << 24));
DISPATCH();
}
BYTECODE(CHECK_4_CHARS) {
uint32_t c = Load32Aligned(pc + 4);
if (c == current_char) {
SET_PC_FROM_OFFSET(Load32Aligned(pc + 8));
} else {
ADVANCE(CHECK_4_CHARS);
}
DISPATCH();
}
BYTECODE(CHECK_CHAR) {
uint32_t c = (insn >> BYTECODE_SHIFT);
if (c == current_char) {
SET_PC_FROM_OFFSET(Load32Aligned(pc + 4));
} else {
ADVANCE(CHECK_CHAR);
}
DISPATCH();
}
BYTECODE(CHECK_NOT_4_CHARS) {
uint32_t c = Load32Aligned(pc + 4);
if (c != current_char) {
SET_PC_FROM_OFFSET(Load32Aligned(pc + 8));
} else {
ADVANCE(CHECK_NOT_4_CHARS);
}
DISPATCH();
}
BYTECODE(CHECK_NOT_CHAR) {
uint32_t c = (insn >> BYTECODE_SHIFT);
if (c != current_char) {
SET_PC_FROM_OFFSET(Load32Aligned(pc + 4));
} else {
ADVANCE(CHECK_NOT_CHAR);
}
DISPATCH();
}
BYTECODE(AND_CHECK_4_CHARS) {
uint32_t c = Load32Aligned(pc + 4);
if (c == (current_char & Load32Aligned(pc + 8))) {
SET_PC_FROM_OFFSET(Load32Aligned(pc + 12));
} else {
ADVANCE(AND_CHECK_4_CHARS);
}
DISPATCH();
}
BYTECODE(AND_CHECK_CHAR) {
uint32_t c = (insn >> BYTECODE_SHIFT);
if (c == (current_char & Load32Aligned(pc + 4))) {
SET_PC_FROM_OFFSET(Load32Aligned(pc + 8));
} else {
ADVANCE(AND_CHECK_CHAR);
}
DISPATCH();
}
BYTECODE(AND_CHECK_NOT_4_CHARS) {
uint32_t c = Load32Aligned(pc + 4);
if (c != (current_char & Load32Aligned(pc + 8))) {
SET_PC_FROM_OFFSET(Load32Aligned(pc + 12));
} else {
ADVANCE(AND_CHECK_NOT_4_CHARS);
}
DISPATCH();
}
BYTECODE(AND_CHECK_NOT_CHAR) {
uint32_t c = (insn >> BYTECODE_SHIFT);
if (c != (current_char & Load32Aligned(pc + 4))) {
SET_PC_FROM_OFFSET(Load32Aligned(pc + 8));
} else {
ADVANCE(AND_CHECK_NOT_CHAR);
}
DISPATCH();
}
BYTECODE(MINUS_AND_CHECK_NOT_CHAR) {
uint32_t c = (insn >> BYTECODE_SHIFT);
uint32_t minus = Load16Aligned(pc + 4);
uint32_t mask = Load16Aligned(pc + 6);
if (c != ((current_char - minus) & mask)) {
SET_PC_FROM_OFFSET(Load32Aligned(pc + 8));
} else {
ADVANCE(MINUS_AND_CHECK_NOT_CHAR);
}
DISPATCH();
}
BYTECODE(CHECK_CHAR_IN_RANGE) {
uint32_t from = Load16Aligned(pc + 4);
uint32_t to = Load16Aligned(pc + 6);
if (from <= current_char && current_char <= to) {
SET_PC_FROM_OFFSET(Load32Aligned(pc + 8));
} else {
ADVANCE(CHECK_CHAR_IN_RANGE);
}
DISPATCH();
}
BYTECODE(CHECK_CHAR_NOT_IN_RANGE) {
uint32_t from = Load16Aligned(pc + 4);
uint32_t to = Load16Aligned(pc + 6);
if (from > current_char || current_char > to) {
SET_PC_FROM_OFFSET(Load32Aligned(pc + 8));
} else {
ADVANCE(CHECK_CHAR_NOT_IN_RANGE);
}
DISPATCH();
}
BYTECODE(CHECK_BIT_IN_TABLE) {
int mask = RegExpMacroAssembler::kTableMask;
byte b = pc[8 + ((current_char & mask) >> kBitsPerByteLog2)];
int bit = (current_char & (kBitsPerByte - 1));
if ((b & (1 << bit)) != 0) {
SET_PC_FROM_OFFSET(Load32Aligned(pc + 4));
} else {
ADVANCE(CHECK_BIT_IN_TABLE);
}
DISPATCH();
}
BYTECODE(CHECK_LT) {
uint32_t limit = (insn >> BYTECODE_SHIFT);
if (current_char < limit) {
SET_PC_FROM_OFFSET(Load32Aligned(pc + 4));
} else {
ADVANCE(CHECK_LT);
}
DISPATCH();
}
BYTECODE(CHECK_GT) {
uint32_t limit = (insn >> BYTECODE_SHIFT);
if (current_char > limit) {
SET_PC_FROM_OFFSET(Load32Aligned(pc + 4));
} else {
ADVANCE(CHECK_GT);
}
DISPATCH();
}
BYTECODE(CHECK_REGISTER_LT) {
if (registers[insn >> BYTECODE_SHIFT] < Load32Aligned(pc + 4)) {
SET_PC_FROM_OFFSET(Load32Aligned(pc + 8));
} else {
ADVANCE(CHECK_REGISTER_LT);
}
DISPATCH();
}
BYTECODE(CHECK_REGISTER_GE) {
if (registers[insn >> BYTECODE_SHIFT] >= Load32Aligned(pc + 4)) {
SET_PC_FROM_OFFSET(Load32Aligned(pc + 8));
} else {
ADVANCE(CHECK_REGISTER_GE);
}
DISPATCH();
}
BYTECODE(CHECK_REGISTER_EQ_POS) {
if (registers[insn >> BYTECODE_SHIFT] == current) {
SET_PC_FROM_OFFSET(Load32Aligned(pc + 4));
} else {
ADVANCE(CHECK_REGISTER_EQ_POS);
}
DISPATCH();
}
BYTECODE(CHECK_NOT_REGS_EQUAL) {
if (registers[insn >> BYTECODE_SHIFT] ==
registers[Load32Aligned(pc + 4)]) {
ADVANCE(CHECK_NOT_REGS_EQUAL);
} else {
SET_PC_FROM_OFFSET(Load32Aligned(pc + 8));
}
DISPATCH();
}
BYTECODE(CHECK_NOT_BACK_REF) {
int from = registers[insn >> BYTECODE_SHIFT];
int len = registers[(insn >> BYTECODE_SHIFT) + 1] - from;
if (from >= 0 && len > 0) {
if (current + len > subject.length() ||
CompareChars(&subject[from], &subject[current], len) != 0) {
SET_PC_FROM_OFFSET(Load32Aligned(pc + 4));
DISPATCH();
}
current += len;
}
ADVANCE(CHECK_NOT_BACK_REF);
DISPATCH();
}
BYTECODE(CHECK_NOT_BACK_REF_BACKWARD) {
int from = registers[insn >> BYTECODE_SHIFT];
int len = registers[(insn >> BYTECODE_SHIFT) + 1] - from;
if (from >= 0 && len > 0) {
if (current - len < 0 ||
CompareChars(&subject[from], &subject[current - len], len) != 0) {
SET_PC_FROM_OFFSET(Load32Aligned(pc + 4));
DISPATCH();
}
current -= len;
}
ADVANCE(CHECK_NOT_BACK_REF_BACKWARD);
DISPATCH();
}
BYTECODE(CHECK_NOT_BACK_REF_NO_CASE_UNICODE) {
int from = registers[insn >> BYTECODE_SHIFT];
int len = registers[(insn >> BYTECODE_SHIFT) + 1] - from;
if (from >= 0 && len > 0) {
if (current + len > subject.length() ||
!BackRefMatchesNoCase(isolate, from, current, len, subject, true)) {
SET_PC_FROM_OFFSET(Load32Aligned(pc + 4));
DISPATCH();
}
current += len;
}
ADVANCE(CHECK_NOT_BACK_REF_NO_CASE_UNICODE);
DISPATCH();
}
BYTECODE(CHECK_NOT_BACK_REF_NO_CASE) {
int from = registers[insn >> BYTECODE_SHIFT];
int len = registers[(insn >> BYTECODE_SHIFT) + 1] - from;
if (from >= 0 && len > 0) {
if (current + len > subject.length() ||
!BackRefMatchesNoCase(isolate, from, current, len, subject,
false)) {
SET_PC_FROM_OFFSET(Load32Aligned(pc + 4));
DISPATCH();
}
current += len;
}
ADVANCE(CHECK_NOT_BACK_REF_NO_CASE);
DISPATCH();
}
BYTECODE(CHECK_NOT_BACK_REF_NO_CASE_UNICODE_BACKWARD) {
int from = registers[insn >> BYTECODE_SHIFT];
int len = registers[(insn >> BYTECODE_SHIFT) + 1] - from;
if (from >= 0 && len > 0) {
if (current - len < 0 ||
!BackRefMatchesNoCase(isolate, from, current - len, len, subject,
true)) {
SET_PC_FROM_OFFSET(Load32Aligned(pc + 4));
DISPATCH();
}
current -= len;
}
ADVANCE(CHECK_NOT_BACK_REF_NO_CASE_UNICODE_BACKWARD);
DISPATCH();
}
BYTECODE(CHECK_NOT_BACK_REF_NO_CASE_BACKWARD) {
int from = registers[insn >> BYTECODE_SHIFT];
int len = registers[(insn >> BYTECODE_SHIFT) + 1] - from;
if (from >= 0 && len > 0) {
if (current - len < 0 ||
!BackRefMatchesNoCase(isolate, from, current - len, len, subject,
false)) {
SET_PC_FROM_OFFSET(Load32Aligned(pc + 4));
DISPATCH();
}
current -= len;
}
ADVANCE(CHECK_NOT_BACK_REF_NO_CASE_BACKWARD);
DISPATCH();
}
BYTECODE(CHECK_AT_START) {
if (current + (insn >> BYTECODE_SHIFT) == 0) {
SET_PC_FROM_OFFSET(Load32Aligned(pc + 4));
} else {
ADVANCE(CHECK_AT_START);
}
DISPATCH();
}
BYTECODE(CHECK_NOT_AT_START) {
if (current + (insn >> BYTECODE_SHIFT) == 0) {
ADVANCE(CHECK_NOT_AT_START);
} else {
SET_PC_FROM_OFFSET(Load32Aligned(pc + 4));
}
DISPATCH();
}
BYTECODE(SET_CURRENT_POSITION_FROM_END) {
ADVANCE(SET_CURRENT_POSITION_FROM_END);
int by = static_cast<uint32_t>(insn) >> BYTECODE_SHIFT;
if (subject.length() - current > by) {
current = subject.length() - by;
current_char = subject[current - 1];
}
DISPATCH();
}
BYTECODE(CHECK_CURRENT_POSITION) {
int pos = current + (insn >> BYTECODE_SHIFT);
if (pos > subject.length() || pos < 0) {
SET_PC_FROM_OFFSET(Load32Aligned(pc + 4));
} else {
ADVANCE(CHECK_CURRENT_POSITION);
}
DISPATCH();
}
#if V8_USE_COMPUTED_GOTO
// Lint gets confused a lot if we just use !V8_USE_COMPUTED_GOTO or ifndef
// V8_USE_COMPUTED_GOTO here.
#else
default:
UNREACHABLE();
}
#endif // V8_USE_COMPUTED_GOTO
}
}
#undef BYTECODE
#undef DISPATCH
#undef DECODE
#undef SET_PC_FROM_OFFSET
#undef ADVANCE
#undef BC_LABEL
#undef V8_USE_COMPUTED_GOTO
} // namespace
// static
void IrregexpInterpreter::Disassemble(ByteArray byte_array,
const std::string& pattern) {
DisallowHeapAllocation no_gc;
PrintF("[generated bytecode for regexp pattern: '%s']\n", pattern.c_str());
const byte* const code_base = byte_array.GetDataStartAddress();
const int byte_array_length = byte_array.length();
ptrdiff_t offset = 0;
while (offset < byte_array_length) {
const byte* const pc = code_base + offset;
PrintF("%p %4" V8PRIxPTRDIFF " ", pc, offset);
DisassembleSingleBytecode(code_base, pc);
offset += RegExpBytecodeLength(*pc);
}
}
// static
IrregexpInterpreter::Result IrregexpInterpreter::Match(
Isolate* isolate, JSRegExp regexp, String subject_string, int* registers,
int registers_length, int start_position, RegExp::CallOrigin call_origin) {
if (FLAG_regexp_tier_up) {
regexp.MarkTierUpForNextExec();
}
bool is_one_byte = String::IsOneByteRepresentationUnderneath(subject_string);
ByteArray code_array = ByteArray::cast(regexp.Bytecode(is_one_byte));
return MatchInternal(isolate, code_array, subject_string, registers,
registers_length, start_position, call_origin);
}
IrregexpInterpreter::Result IrregexpInterpreter::MatchInternal(
Isolate* isolate, ByteArray code_array, String subject_string,
int* registers, int registers_length, int start_position,
RegExp::CallOrigin call_origin) {
DCHECK(subject_string.IsFlat());
// Note: Heap allocation *is* allowed in two situations if calling from
// Runtime:
// 1. When creating & throwing a stack overflow exception. The interpreter
// aborts afterwards, and thus possible-moved objects are never used.
// 2. When handling interrupts. We manually relocate unhandlified references
// after interrupts have run.
DisallowHeapAllocation no_gc;
// Reset registers to -1 (=undefined).
// This is necessary because registers are only written when a
// capture group matched.
// Resetting them ensures that previous matches are cleared.
memset(registers, -1, sizeof(registers[0]) * registers_length);
uc16 previous_char = '\n';
String::FlatContent subject_content = subject_string.GetFlatContent(no_gc);
if (subject_content.IsOneByte()) {
Vector<const uint8_t> subject_vector = subject_content.ToOneByteVector();
if (start_position != 0) previous_char = subject_vector[start_position - 1];
return RawMatch(isolate, code_array, subject_string, subject_vector,
registers, start_position, previous_char, call_origin);
} else {
DCHECK(subject_content.IsTwoByte());
Vector<const uc16> subject_vector = subject_content.ToUC16Vector();
if (start_position != 0) previous_char = subject_vector[start_position - 1];
return RawMatch(isolate, code_array, subject_string, subject_vector,
registers, start_position, previous_char, call_origin);
}
}
// This method is called through an external reference from RegExpExecInternal
// builtin.
IrregexpInterpreter::Result IrregexpInterpreter::MatchForCallFromJs(
Address subject, int32_t start_position, Address, Address, int* registers,
int32_t registers_length, Address, RegExp::CallOrigin call_origin,
Isolate* isolate, Address regexp) {
DCHECK_NOT_NULL(isolate);
DCHECK_NOT_NULL(registers);
DCHECK(call_origin == RegExp::CallOrigin::kFromJs);
DisallowHeapAllocation no_gc;
DisallowJavascriptExecution no_js(isolate);
String subject_string = String::cast(Object(subject));
JSRegExp regexp_obj = JSRegExp::cast(Object(regexp));
return Match(isolate, regexp_obj, subject_string, registers, registers_length,
start_position, call_origin);
}
IrregexpInterpreter::Result IrregexpInterpreter::MatchForCallFromRuntime(
Isolate* isolate, Handle<JSRegExp> regexp, Handle<String> subject_string,
int* registers, int registers_length, int start_position) {
return Match(isolate, *regexp, *subject_string, registers, registers_length,
start_position, RegExp::CallOrigin::kFromRuntime);
}
} // namespace internal
} // namespace v8