Upgrade V8 to version 4.9.385.28

https://chromium.googlesource.com/v8/v8/+/4.9.385.28

Change-Id: I4b2e74289d4bf3667f2f3dc8aa2e541f63e26eb4
diff --git a/src/regexp/x64/regexp-macro-assembler-x64.cc b/src/regexp/x64/regexp-macro-assembler-x64.cc
new file mode 100644
index 0000000..286f159
--- /dev/null
+++ b/src/regexp/x64/regexp-macro-assembler-x64.cc
@@ -0,0 +1,1392 @@
+// Copyright 2012 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.
+
+#if V8_TARGET_ARCH_X64
+
+#include "src/regexp/x64/regexp-macro-assembler-x64.h"
+
+#include "src/log.h"
+#include "src/macro-assembler.h"
+#include "src/profiler/cpu-profiler.h"
+#include "src/regexp/regexp-macro-assembler.h"
+#include "src/regexp/regexp-stack.h"
+#include "src/unicode.h"
+
+namespace v8 {
+namespace internal {
+
+#ifndef V8_INTERPRETED_REGEXP
+
+/*
+ * This assembler uses the following register assignment convention
+ * - rdx : Currently loaded character(s) as Latin1 or UC16.  Must be loaded
+ *         using LoadCurrentCharacter before using any of the dispatch methods.
+ *         Temporarily stores the index of capture start after a matching pass
+ *         for a global regexp.
+ * - rdi : Current position in input, as negative offset from end of string.
+ *         Please notice that this is the byte offset, not the character
+ *         offset!  Is always a 32-bit signed (negative) offset, but must be
+ *         maintained sign-extended to 64 bits, since it is used as index.
+ * - rsi : End of input (points to byte after last character in input),
+ *         so that rsi+rdi points to the current character.
+ * - rbp : Frame pointer.  Used to access arguments, local variables and
+ *         RegExp registers.
+ * - rsp : Points to tip of C stack.
+ * - rcx : Points to tip of backtrack stack.  The backtrack stack contains
+ *         only 32-bit values.  Most are offsets from some base (e.g., character
+ *         positions from end of string or code location from Code* pointer).
+ * - r8  : Code object pointer.  Used to convert between absolute and
+ *         code-object-relative addresses.
+ *
+ * The registers rax, rbx, r9 and r11 are free to use for computations.
+ * If changed to use r12+, they should be saved as callee-save registers.
+ * The macro assembler special register r13 (kRootRegister) isn't special
+ * during execution of RegExp code (it doesn't hold the value assumed when
+ * creating JS code), so Root related macro operations can be used.
+ *
+ * Each call to a C++ method should retain these registers.
+ *
+ * The stack will have the following content, in some order, indexable from the
+ * frame pointer (see, e.g., kStackHighEnd):
+ *    - Isolate* isolate     (address of the current isolate)
+ *    - direct_call          (if 1, direct call from JavaScript code, if 0 call
+ *                            through the runtime system)
+ *    - stack_area_base      (high end of the memory area to use as
+ *                            backtracking stack)
+ *    - capture array size   (may fit multiple sets of matches)
+ *    - int* capture_array   (int[num_saved_registers_], for output).
+ *    - end of input         (address of end of string)
+ *    - start of input       (address of first character in string)
+ *    - start index          (character index of start)
+ *    - String* input_string (input string)
+ *    - return address
+ *    - backup of callee save registers (rbx, possibly rsi and rdi).
+ *    - success counter      (only useful for global regexp to count matches)
+ *    - Offset of location before start of input (effectively character
+ *      string start - 1).  Used to initialize capture registers to a
+ *      non-position.
+ *    - At start of string (if 1, we are starting at the start of the
+ *      string, otherwise 0)
+ *    - register 0  rbp[-n]   (Only positions must be stored in the first
+ *    - register 1  rbp[-n-8]  num_saved_registers_ registers)
+ *    - ...
+ *
+ * The first num_saved_registers_ registers are initialized to point to
+ * "character -1" in the string (i.e., char_size() bytes before the first
+ * character of the string).  The remaining registers starts out uninitialized.
+ *
+ * The first seven values must be provided by the calling code by
+ * calling the code's entry address cast to a function pointer with the
+ * following signature:
+ * int (*match)(String* input_string,
+ *              int start_index,
+ *              Address start,
+ *              Address end,
+ *              int* capture_output_array,
+ *              bool at_start,
+ *              byte* stack_area_base,
+ *              bool direct_call)
+ */
+
+#define __ ACCESS_MASM((&masm_))
+
+RegExpMacroAssemblerX64::RegExpMacroAssemblerX64(Isolate* isolate, Zone* zone,
+                                                 Mode mode,
+                                                 int registers_to_save)
+    : NativeRegExpMacroAssembler(isolate, zone),
+      masm_(isolate, NULL, kRegExpCodeSize, CodeObjectRequired::kYes),
+      no_root_array_scope_(&masm_),
+      code_relative_fixup_positions_(4, zone),
+      mode_(mode),
+      num_registers_(registers_to_save),
+      num_saved_registers_(registers_to_save),
+      entry_label_(),
+      start_label_(),
+      success_label_(),
+      backtrack_label_(),
+      exit_label_() {
+  DCHECK_EQ(0, registers_to_save % 2);
+  __ jmp(&entry_label_);   // We'll write the entry code when we know more.
+  __ bind(&start_label_);  // And then continue from here.
+}
+
+
+RegExpMacroAssemblerX64::~RegExpMacroAssemblerX64() {
+  // Unuse labels in case we throw away the assembler without calling GetCode.
+  entry_label_.Unuse();
+  start_label_.Unuse();
+  success_label_.Unuse();
+  backtrack_label_.Unuse();
+  exit_label_.Unuse();
+  check_preempt_label_.Unuse();
+  stack_overflow_label_.Unuse();
+}
+
+
+int RegExpMacroAssemblerX64::stack_limit_slack()  {
+  return RegExpStack::kStackLimitSlack;
+}
+
+
+void RegExpMacroAssemblerX64::AdvanceCurrentPosition(int by) {
+  if (by != 0) {
+    __ addq(rdi, Immediate(by * char_size()));
+  }
+}
+
+
+void RegExpMacroAssemblerX64::AdvanceRegister(int reg, int by) {
+  DCHECK(reg >= 0);
+  DCHECK(reg < num_registers_);
+  if (by != 0) {
+    __ addp(register_location(reg), Immediate(by));
+  }
+}
+
+
+void RegExpMacroAssemblerX64::Backtrack() {
+  CheckPreemption();
+  // Pop Code* offset from backtrack stack, add Code* and jump to location.
+  Pop(rbx);
+  __ addp(rbx, code_object_pointer());
+  __ jmp(rbx);
+}
+
+
+void RegExpMacroAssemblerX64::Bind(Label* label) {
+  __ bind(label);
+}
+
+
+void RegExpMacroAssemblerX64::CheckCharacter(uint32_t c, Label* on_equal) {
+  __ cmpl(current_character(), Immediate(c));
+  BranchOrBacktrack(equal, on_equal);
+}
+
+
+void RegExpMacroAssemblerX64::CheckCharacterGT(uc16 limit, Label* on_greater) {
+  __ cmpl(current_character(), Immediate(limit));
+  BranchOrBacktrack(greater, on_greater);
+}
+
+
+void RegExpMacroAssemblerX64::CheckAtStart(Label* on_at_start) {
+  __ leap(rax, Operand(rdi, -char_size()));
+  __ cmpp(rax, Operand(rbp, kStringStartMinusOne));
+  BranchOrBacktrack(equal, on_at_start);
+}
+
+
+void RegExpMacroAssemblerX64::CheckNotAtStart(int cp_offset,
+                                              Label* on_not_at_start) {
+  __ leap(rax, Operand(rdi, -char_size() + cp_offset * char_size()));
+  __ cmpp(rax, Operand(rbp, kStringStartMinusOne));
+  BranchOrBacktrack(not_equal, on_not_at_start);
+}
+
+
+void RegExpMacroAssemblerX64::CheckCharacterLT(uc16 limit, Label* on_less) {
+  __ cmpl(current_character(), Immediate(limit));
+  BranchOrBacktrack(less, on_less);
+}
+
+
+void RegExpMacroAssemblerX64::CheckGreedyLoop(Label* on_equal) {
+  Label fallthrough;
+  __ cmpl(rdi, Operand(backtrack_stackpointer(), 0));
+  __ j(not_equal, &fallthrough);
+  Drop();
+  BranchOrBacktrack(no_condition, on_equal);
+  __ bind(&fallthrough);
+}
+
+
+void RegExpMacroAssemblerX64::CheckNotBackReferenceIgnoreCase(
+    int start_reg, bool read_backward, Label* on_no_match) {
+  Label fallthrough;
+  ReadPositionFromRegister(rdx, start_reg);  // Offset of start of capture
+  ReadPositionFromRegister(rbx, start_reg + 1);  // Offset of end of capture
+  __ subp(rbx, rdx);  // Length of capture.
+
+  // -----------------------
+  // rdx  = Start offset of capture.
+  // rbx = Length of capture
+
+  // At this point, the capture registers are either both set or both cleared.
+  // If the capture length is zero, then the capture is either empty or cleared.
+  // Fall through in both cases.
+  __ j(equal, &fallthrough);
+
+  // -----------------------
+  // rdx - Start of capture
+  // rbx - length of capture
+  // Check that there are sufficient characters left in the input.
+  if (read_backward) {
+    __ movl(rax, Operand(rbp, kStringStartMinusOne));
+    __ addl(rax, rbx);
+    __ cmpl(rdi, rax);
+    BranchOrBacktrack(less_equal, on_no_match);
+  } else {
+    __ movl(rax, rdi);
+    __ addl(rax, rbx);
+    BranchOrBacktrack(greater, on_no_match);
+  }
+
+  if (mode_ == LATIN1) {
+    Label loop_increment;
+    if (on_no_match == NULL) {
+      on_no_match = &backtrack_label_;
+    }
+
+    __ leap(r9, Operand(rsi, rdx, times_1, 0));
+    __ leap(r11, Operand(rsi, rdi, times_1, 0));
+    if (read_backward) {
+      __ subp(r11, rbx);  // Offset by length when matching backwards.
+    }
+    __ addp(rbx, r9);  // End of capture
+    // ---------------------
+    // r11 - current input character address
+    // r9 - current capture character address
+    // rbx - end of capture
+
+    Label loop;
+    __ bind(&loop);
+    __ movzxbl(rdx, Operand(r9, 0));
+    __ movzxbl(rax, Operand(r11, 0));
+    // al - input character
+    // dl - capture character
+    __ cmpb(rax, rdx);
+    __ j(equal, &loop_increment);
+
+    // Mismatch, try case-insensitive match (converting letters to lower-case).
+    // I.e., if or-ing with 0x20 makes values equal and in range 'a'-'z', it's
+    // a match.
+    __ orp(rax, Immediate(0x20));  // Convert match character to lower-case.
+    __ orp(rdx, Immediate(0x20));  // Convert capture character to lower-case.
+    __ cmpb(rax, rdx);
+    __ j(not_equal, on_no_match);  // Definitely not equal.
+    __ subb(rax, Immediate('a'));
+    __ cmpb(rax, Immediate('z' - 'a'));
+    __ j(below_equal, &loop_increment);  // In range 'a'-'z'.
+    // Latin-1: Check for values in range [224,254] but not 247.
+    __ subb(rax, Immediate(224 - 'a'));
+    __ cmpb(rax, Immediate(254 - 224));
+    __ j(above, on_no_match);  // Weren't Latin-1 letters.
+    __ cmpb(rax, Immediate(247 - 224));  // Check for 247.
+    __ j(equal, on_no_match);
+    __ bind(&loop_increment);
+    // Increment pointers into match and capture strings.
+    __ addp(r11, Immediate(1));
+    __ addp(r9, Immediate(1));
+    // Compare to end of capture, and loop if not done.
+    __ cmpp(r9, rbx);
+    __ j(below, &loop);
+
+    // Compute new value of character position after the matched part.
+    __ movp(rdi, r11);
+    __ subq(rdi, rsi);
+    if (read_backward) {
+      // Subtract match length if we matched backward.
+      __ addq(rdi, register_location(start_reg));
+      __ subq(rdi, register_location(start_reg + 1));
+    }
+  } else {
+    DCHECK(mode_ == UC16);
+    // Save important/volatile registers before calling C function.
+#ifndef _WIN64
+    // Caller save on Linux and callee save in Windows.
+    __ pushq(rsi);
+    __ pushq(rdi);
+#endif
+    __ pushq(backtrack_stackpointer());
+
+    static const int num_arguments = 4;
+    __ PrepareCallCFunction(num_arguments);
+
+    // Put arguments into parameter registers. Parameters are
+    //   Address byte_offset1 - Address captured substring's start.
+    //   Address byte_offset2 - Address of current character position.
+    //   size_t byte_length - length of capture in bytes(!)
+    //   Isolate* isolate
+#ifdef _WIN64
+    // Compute and set byte_offset1 (start of capture).
+    __ leap(rcx, Operand(rsi, rdx, times_1, 0));
+    // Set byte_offset2.
+    __ leap(rdx, Operand(rsi, rdi, times_1, 0));
+    if (read_backward) {
+      __ subq(rdx, rbx);
+    }
+    // Set byte_length.
+    __ movp(r8, rbx);
+    // Isolate.
+    __ LoadAddress(r9, ExternalReference::isolate_address(isolate()));
+#else  // AMD64 calling convention
+    // Compute byte_offset2 (current position = rsi+rdi).
+    __ leap(rax, Operand(rsi, rdi, times_1, 0));
+    // Compute and set byte_offset1 (start of capture).
+    __ leap(rdi, Operand(rsi, rdx, times_1, 0));
+    // Set byte_offset2.
+    __ movp(rsi, rax);
+    if (read_backward) {
+      __ subq(rsi, rbx);
+    }
+    // Set byte_length.
+    __ movp(rdx, rbx);
+    // Isolate.
+    __ LoadAddress(rcx, ExternalReference::isolate_address(isolate()));
+#endif
+
+    { // NOLINT: Can't find a way to open this scope without confusing the
+      // linter.
+      AllowExternalCallThatCantCauseGC scope(&masm_);
+      ExternalReference compare =
+          ExternalReference::re_case_insensitive_compare_uc16(isolate());
+      __ CallCFunction(compare, num_arguments);
+    }
+
+    // Restore original values before reacting on result value.
+    __ Move(code_object_pointer(), masm_.CodeObject());
+    __ popq(backtrack_stackpointer());
+#ifndef _WIN64
+    __ popq(rdi);
+    __ popq(rsi);
+#endif
+
+    // Check if function returned non-zero for success or zero for failure.
+    __ testp(rax, rax);
+    BranchOrBacktrack(zero, on_no_match);
+    // On success, advance position by length of capture.
+    // Requires that rbx is callee save (true for both Win64 and AMD64 ABIs).
+    if (read_backward) {
+      __ subq(rdi, rbx);
+    } else {
+      __ addq(rdi, rbx);
+    }
+  }
+  __ bind(&fallthrough);
+}
+
+
+void RegExpMacroAssemblerX64::CheckNotBackReference(int start_reg,
+                                                    bool read_backward,
+                                                    Label* on_no_match) {
+  Label fallthrough;
+
+  // Find length of back-referenced capture.
+  ReadPositionFromRegister(rdx, start_reg);  // Offset of start of capture
+  ReadPositionFromRegister(rax, start_reg + 1);  // Offset of end of capture
+  __ subp(rax, rdx);  // Length to check.
+
+  // At this point, the capture registers are either both set or both cleared.
+  // If the capture length is zero, then the capture is either empty or cleared.
+  // Fall through in both cases.
+  __ j(equal, &fallthrough);
+
+  // -----------------------
+  // rdx - Start of capture
+  // rax - length of capture
+  // Check that there are sufficient characters left in the input.
+  if (read_backward) {
+    __ movl(rbx, Operand(rbp, kStringStartMinusOne));
+    __ addl(rbx, rax);
+    __ cmpl(rdi, rbx);
+    BranchOrBacktrack(less_equal, on_no_match);
+  } else {
+    __ movl(rbx, rdi);
+    __ addl(rbx, rax);
+    BranchOrBacktrack(greater, on_no_match);
+  }
+
+  // Compute pointers to match string and capture string
+  __ leap(rbx, Operand(rsi, rdi, times_1, 0));  // Start of match.
+  if (read_backward) {
+    __ subq(rbx, rax);  // Offset by length when matching backwards.
+  }
+  __ addp(rdx, rsi);  // Start of capture.
+  __ leap(r9, Operand(rdx, rax, times_1, 0));  // End of capture
+
+  // -----------------------
+  // rbx - current capture character address.
+  // rbx - current input character address .
+  // r9 - end of input to match (capture length after rbx).
+
+  Label loop;
+  __ bind(&loop);
+  if (mode_ == LATIN1) {
+    __ movzxbl(rax, Operand(rdx, 0));
+    __ cmpb(rax, Operand(rbx, 0));
+  } else {
+    DCHECK(mode_ == UC16);
+    __ movzxwl(rax, Operand(rdx, 0));
+    __ cmpw(rax, Operand(rbx, 0));
+  }
+  BranchOrBacktrack(not_equal, on_no_match);
+  // Increment pointers into capture and match string.
+  __ addp(rbx, Immediate(char_size()));
+  __ addp(rdx, Immediate(char_size()));
+  // Check if we have reached end of match area.
+  __ cmpp(rdx, r9);
+  __ j(below, &loop);
+
+  // Success.
+  // Set current character position to position after match.
+  __ movp(rdi, rbx);
+  __ subq(rdi, rsi);
+  if (read_backward) {
+    // Subtract match length if we matched backward.
+    __ addq(rdi, register_location(start_reg));
+    __ subq(rdi, register_location(start_reg + 1));
+  }
+
+  __ bind(&fallthrough);
+}
+
+
+void RegExpMacroAssemblerX64::CheckNotCharacter(uint32_t c,
+                                                Label* on_not_equal) {
+  __ cmpl(current_character(), Immediate(c));
+  BranchOrBacktrack(not_equal, on_not_equal);
+}
+
+
+void RegExpMacroAssemblerX64::CheckCharacterAfterAnd(uint32_t c,
+                                                     uint32_t mask,
+                                                     Label* on_equal) {
+  if (c == 0) {
+    __ testl(current_character(), Immediate(mask));
+  } else {
+    __ movl(rax, Immediate(mask));
+    __ andp(rax, current_character());
+    __ cmpl(rax, Immediate(c));
+  }
+  BranchOrBacktrack(equal, on_equal);
+}
+
+
+void RegExpMacroAssemblerX64::CheckNotCharacterAfterAnd(uint32_t c,
+                                                        uint32_t mask,
+                                                        Label* on_not_equal) {
+  if (c == 0) {
+    __ testl(current_character(), Immediate(mask));
+  } else {
+    __ movl(rax, Immediate(mask));
+    __ andp(rax, current_character());
+    __ cmpl(rax, Immediate(c));
+  }
+  BranchOrBacktrack(not_equal, on_not_equal);
+}
+
+
+void RegExpMacroAssemblerX64::CheckNotCharacterAfterMinusAnd(
+    uc16 c,
+    uc16 minus,
+    uc16 mask,
+    Label* on_not_equal) {
+  DCHECK(minus < String::kMaxUtf16CodeUnit);
+  __ leap(rax, Operand(current_character(), -minus));
+  __ andp(rax, Immediate(mask));
+  __ cmpl(rax, Immediate(c));
+  BranchOrBacktrack(not_equal, on_not_equal);
+}
+
+
+void RegExpMacroAssemblerX64::CheckCharacterInRange(
+    uc16 from,
+    uc16 to,
+    Label* on_in_range) {
+  __ leal(rax, Operand(current_character(), -from));
+  __ cmpl(rax, Immediate(to - from));
+  BranchOrBacktrack(below_equal, on_in_range);
+}
+
+
+void RegExpMacroAssemblerX64::CheckCharacterNotInRange(
+    uc16 from,
+    uc16 to,
+    Label* on_not_in_range) {
+  __ leal(rax, Operand(current_character(), -from));
+  __ cmpl(rax, Immediate(to - from));
+  BranchOrBacktrack(above, on_not_in_range);
+}
+
+
+void RegExpMacroAssemblerX64::CheckBitInTable(
+    Handle<ByteArray> table,
+    Label* on_bit_set) {
+  __ Move(rax, table);
+  Register index = current_character();
+  if (mode_ != LATIN1 || kTableMask != String::kMaxOneByteCharCode) {
+    __ movp(rbx, current_character());
+    __ andp(rbx, Immediate(kTableMask));
+    index = rbx;
+  }
+  __ cmpb(FieldOperand(rax, index, times_1, ByteArray::kHeaderSize),
+          Immediate(0));
+  BranchOrBacktrack(not_equal, on_bit_set);
+}
+
+
+bool RegExpMacroAssemblerX64::CheckSpecialCharacterClass(uc16 type,
+                                                         Label* on_no_match) {
+  // Range checks (c in min..max) are generally implemented by an unsigned
+  // (c - min) <= (max - min) check, using the sequence:
+  //   leap(rax, Operand(current_character(), -min)) or sub(rax, Immediate(min))
+  //   cmp(rax, Immediate(max - min))
+  switch (type) {
+  case 's':
+    // Match space-characters
+    if (mode_ == LATIN1) {
+      // One byte space characters are '\t'..'\r', ' ' and \u00a0.
+      Label success;
+      __ cmpl(current_character(), Immediate(' '));
+      __ j(equal, &success, Label::kNear);
+      // Check range 0x09..0x0d
+      __ leap(rax, Operand(current_character(), -'\t'));
+      __ cmpl(rax, Immediate('\r' - '\t'));
+      __ j(below_equal, &success, Label::kNear);
+      // \u00a0 (NBSP).
+      __ cmpl(rax, Immediate(0x00a0 - '\t'));
+      BranchOrBacktrack(not_equal, on_no_match);
+      __ bind(&success);
+      return true;
+    }
+    return false;
+  case 'S':
+    // The emitted code for generic character classes is good enough.
+    return false;
+  case 'd':
+    // Match ASCII digits ('0'..'9')
+    __ leap(rax, Operand(current_character(), -'0'));
+    __ cmpl(rax, Immediate('9' - '0'));
+    BranchOrBacktrack(above, on_no_match);
+    return true;
+  case 'D':
+    // Match non ASCII-digits
+    __ leap(rax, Operand(current_character(), -'0'));
+    __ cmpl(rax, Immediate('9' - '0'));
+    BranchOrBacktrack(below_equal, on_no_match);
+    return true;
+  case '.': {
+    // Match non-newlines (not 0x0a('\n'), 0x0d('\r'), 0x2028 and 0x2029)
+    __ movl(rax, current_character());
+    __ xorp(rax, Immediate(0x01));
+    // See if current character is '\n'^1 or '\r'^1, i.e., 0x0b or 0x0c
+    __ subl(rax, Immediate(0x0b));
+    __ cmpl(rax, Immediate(0x0c - 0x0b));
+    BranchOrBacktrack(below_equal, on_no_match);
+    if (mode_ == UC16) {
+      // Compare original value to 0x2028 and 0x2029, using the already
+      // computed (current_char ^ 0x01 - 0x0b). I.e., check for
+      // 0x201d (0x2028 - 0x0b) or 0x201e.
+      __ subl(rax, Immediate(0x2028 - 0x0b));
+      __ cmpl(rax, Immediate(0x2029 - 0x2028));
+      BranchOrBacktrack(below_equal, on_no_match);
+    }
+    return true;
+  }
+  case 'n': {
+    // Match newlines (0x0a('\n'), 0x0d('\r'), 0x2028 and 0x2029)
+    __ movl(rax, current_character());
+    __ xorp(rax, Immediate(0x01));
+    // See if current character is '\n'^1 or '\r'^1, i.e., 0x0b or 0x0c
+    __ subl(rax, Immediate(0x0b));
+    __ cmpl(rax, Immediate(0x0c - 0x0b));
+    if (mode_ == LATIN1) {
+      BranchOrBacktrack(above, on_no_match);
+    } else {
+      Label done;
+      BranchOrBacktrack(below_equal, &done);
+      // Compare original value to 0x2028 and 0x2029, using the already
+      // computed (current_char ^ 0x01 - 0x0b). I.e., check for
+      // 0x201d (0x2028 - 0x0b) or 0x201e.
+      __ subl(rax, Immediate(0x2028 - 0x0b));
+      __ cmpl(rax, Immediate(0x2029 - 0x2028));
+      BranchOrBacktrack(above, on_no_match);
+      __ bind(&done);
+    }
+    return true;
+  }
+  case 'w': {
+    if (mode_ != LATIN1) {
+      // Table is 256 entries, so all Latin1 characters can be tested.
+      __ cmpl(current_character(), Immediate('z'));
+      BranchOrBacktrack(above, on_no_match);
+    }
+    __ Move(rbx, ExternalReference::re_word_character_map());
+    DCHECK_EQ(0, word_character_map[0]);  // Character '\0' is not a word char.
+    __ testb(Operand(rbx, current_character(), times_1, 0),
+             current_character());
+    BranchOrBacktrack(zero, on_no_match);
+    return true;
+  }
+  case 'W': {
+    Label done;
+    if (mode_ != LATIN1) {
+      // Table is 256 entries, so all Latin1 characters can be tested.
+      __ cmpl(current_character(), Immediate('z'));
+      __ j(above, &done);
+    }
+    __ Move(rbx, ExternalReference::re_word_character_map());
+    DCHECK_EQ(0, word_character_map[0]);  // Character '\0' is not a word char.
+    __ testb(Operand(rbx, current_character(), times_1, 0),
+             current_character());
+    BranchOrBacktrack(not_zero, on_no_match);
+    if (mode_ != LATIN1) {
+      __ bind(&done);
+    }
+    return true;
+  }
+
+  case '*':
+    // Match any character.
+    return true;
+  // No custom implementation (yet): s(UC16), S(UC16).
+  default:
+    return false;
+  }
+}
+
+
+void RegExpMacroAssemblerX64::Fail() {
+  STATIC_ASSERT(FAILURE == 0);  // Return value for failure is zero.
+  if (!global()) {
+    __ Set(rax, FAILURE);
+  }
+  __ jmp(&exit_label_);
+}
+
+
+Handle<HeapObject> RegExpMacroAssemblerX64::GetCode(Handle<String> source) {
+  Label return_rax;
+  // Finalize code - write the entry point code now we know how many
+  // registers we need.
+  // Entry code:
+  __ bind(&entry_label_);
+
+  // Tell the system that we have a stack frame.  Because the type is MANUAL, no
+  // is generated.
+  FrameScope scope(&masm_, StackFrame::MANUAL);
+
+  // Actually emit code to start a new stack frame.
+  __ pushq(rbp);
+  __ movp(rbp, rsp);
+  // Save parameters and callee-save registers. Order here should correspond
+  //  to order of kBackup_ebx etc.
+#ifdef _WIN64
+  // MSVC passes arguments in rcx, rdx, r8, r9, with backing stack slots.
+  // Store register parameters in pre-allocated stack slots,
+  __ movq(Operand(rbp, kInputString), rcx);
+  __ movq(Operand(rbp, kStartIndex), rdx);  // Passed as int32 in edx.
+  __ movq(Operand(rbp, kInputStart), r8);
+  __ movq(Operand(rbp, kInputEnd), r9);
+  // Callee-save on Win64.
+  __ pushq(rsi);
+  __ pushq(rdi);
+  __ pushq(rbx);
+#else
+  // GCC passes arguments in rdi, rsi, rdx, rcx, r8, r9 (and then on stack).
+  // Push register parameters on stack for reference.
+  DCHECK_EQ(kInputString, -1 * kRegisterSize);
+  DCHECK_EQ(kStartIndex, -2 * kRegisterSize);
+  DCHECK_EQ(kInputStart, -3 * kRegisterSize);
+  DCHECK_EQ(kInputEnd, -4 * kRegisterSize);
+  DCHECK_EQ(kRegisterOutput, -5 * kRegisterSize);
+  DCHECK_EQ(kNumOutputRegisters, -6 * kRegisterSize);
+  __ pushq(rdi);
+  __ pushq(rsi);
+  __ pushq(rdx);
+  __ pushq(rcx);
+  __ pushq(r8);
+  __ pushq(r9);
+
+  __ pushq(rbx);  // Callee-save
+#endif
+
+  __ Push(Immediate(0));  // Number of successful matches in a global regexp.
+  __ Push(Immediate(0));  // Make room for "string start - 1" constant.
+
+  // Check if we have space on the stack for registers.
+  Label stack_limit_hit;
+  Label stack_ok;
+
+  ExternalReference stack_limit =
+      ExternalReference::address_of_stack_limit(isolate());
+  __ movp(rcx, rsp);
+  __ Move(kScratchRegister, stack_limit);
+  __ subp(rcx, Operand(kScratchRegister, 0));
+  // Handle it if the stack pointer is already below the stack limit.
+  __ j(below_equal, &stack_limit_hit);
+  // Check if there is room for the variable number of registers above
+  // the stack limit.
+  __ cmpp(rcx, Immediate(num_registers_ * kPointerSize));
+  __ j(above_equal, &stack_ok);
+  // Exit with OutOfMemory exception. There is not enough space on the stack
+  // for our working registers.
+  __ Set(rax, EXCEPTION);
+  __ jmp(&return_rax);
+
+  __ bind(&stack_limit_hit);
+  __ Move(code_object_pointer(), masm_.CodeObject());
+  CallCheckStackGuardState();  // Preserves no registers beside rbp and rsp.
+  __ testp(rax, rax);
+  // If returned value is non-zero, we exit with the returned value as result.
+  __ j(not_zero, &return_rax);
+
+  __ bind(&stack_ok);
+
+  // Allocate space on stack for registers.
+  __ subp(rsp, Immediate(num_registers_ * kPointerSize));
+  // Load string length.
+  __ movp(rsi, Operand(rbp, kInputEnd));
+  // Load input position.
+  __ movp(rdi, Operand(rbp, kInputStart));
+  // Set up rdi to be negative offset from string end.
+  __ subq(rdi, rsi);
+  // Set rax to address of char before start of the string
+  // (effectively string position -1).
+  __ movp(rbx, Operand(rbp, kStartIndex));
+  __ negq(rbx);
+  if (mode_ == UC16) {
+    __ leap(rax, Operand(rdi, rbx, times_2, -char_size()));
+  } else {
+    __ leap(rax, Operand(rdi, rbx, times_1, -char_size()));
+  }
+  // Store this value in a local variable, for use when clearing
+  // position registers.
+  __ movp(Operand(rbp, kStringStartMinusOne), rax);
+
+#if V8_OS_WIN
+  // Ensure that we have written to each stack page, in order. Skipping a page
+  // on Windows can cause segmentation faults. Assuming page size is 4k.
+  const int kPageSize = 4096;
+  const int kRegistersPerPage = kPageSize / kPointerSize;
+  for (int i = num_saved_registers_ + kRegistersPerPage - 1;
+      i < num_registers_;
+      i += kRegistersPerPage) {
+    __ movp(register_location(i), rax);  // One write every page.
+  }
+#endif  // V8_OS_WIN
+
+  // Initialize code object pointer.
+  __ Move(code_object_pointer(), masm_.CodeObject());
+
+  Label load_char_start_regexp, start_regexp;
+  // Load newline if index is at start, previous character otherwise.
+  __ cmpl(Operand(rbp, kStartIndex), Immediate(0));
+  __ j(not_equal, &load_char_start_regexp, Label::kNear);
+  __ Set(current_character(), '\n');
+  __ jmp(&start_regexp, Label::kNear);
+
+  // Global regexp restarts matching here.
+  __ bind(&load_char_start_regexp);
+  // Load previous char as initial value of current character register.
+  LoadCurrentCharacterUnchecked(-1, 1);
+  __ bind(&start_regexp);
+
+  // Initialize on-stack registers.
+  if (num_saved_registers_ > 0) {
+    // Fill saved registers with initial value = start offset - 1
+    // Fill in stack push order, to avoid accessing across an unwritten
+    // page (a problem on Windows).
+    if (num_saved_registers_ > 8) {
+      __ Set(rcx, kRegisterZero);
+      Label init_loop;
+      __ bind(&init_loop);
+      __ movp(Operand(rbp, rcx, times_1, 0), rax);
+      __ subq(rcx, Immediate(kPointerSize));
+      __ cmpq(rcx,
+              Immediate(kRegisterZero - num_saved_registers_ * kPointerSize));
+      __ j(greater, &init_loop);
+    } else {  // Unroll the loop.
+      for (int i = 0; i < num_saved_registers_; i++) {
+        __ movp(register_location(i), rax);
+      }
+    }
+  }
+
+  // Initialize backtrack stack pointer.
+  __ movp(backtrack_stackpointer(), Operand(rbp, kStackHighEnd));
+
+  __ jmp(&start_label_);
+
+  // Exit code:
+  if (success_label_.is_linked()) {
+    // Save captures when successful.
+    __ bind(&success_label_);
+    if (num_saved_registers_ > 0) {
+      // copy captures to output
+      __ movp(rdx, Operand(rbp, kStartIndex));
+      __ movp(rbx, Operand(rbp, kRegisterOutput));
+      __ movp(rcx, Operand(rbp, kInputEnd));
+      __ subp(rcx, Operand(rbp, kInputStart));
+      if (mode_ == UC16) {
+        __ leap(rcx, Operand(rcx, rdx, times_2, 0));
+      } else {
+        __ addp(rcx, rdx);
+      }
+      for (int i = 0; i < num_saved_registers_; i++) {
+        __ movp(rax, register_location(i));
+        if (i == 0 && global_with_zero_length_check()) {
+          // Keep capture start in rdx for the zero-length check later.
+          __ movp(rdx, rax);
+        }
+        __ addp(rax, rcx);  // Convert to index from start, not end.
+        if (mode_ == UC16) {
+          __ sarp(rax, Immediate(1));  // Convert byte index to character index.
+        }
+        __ movl(Operand(rbx, i * kIntSize), rax);
+      }
+    }
+
+    if (global()) {
+      // Restart matching if the regular expression is flagged as global.
+      // Increment success counter.
+      __ incp(Operand(rbp, kSuccessfulCaptures));
+      // Capture results have been stored, so the number of remaining global
+      // output registers is reduced by the number of stored captures.
+      __ movsxlq(rcx, Operand(rbp, kNumOutputRegisters));
+      __ subp(rcx, Immediate(num_saved_registers_));
+      // Check whether we have enough room for another set of capture results.
+      __ cmpp(rcx, Immediate(num_saved_registers_));
+      __ j(less, &exit_label_);
+
+      __ movp(Operand(rbp, kNumOutputRegisters), rcx);
+      // Advance the location for output.
+      __ addp(Operand(rbp, kRegisterOutput),
+              Immediate(num_saved_registers_ * kIntSize));
+
+      // Prepare rax to initialize registers with its value in the next run.
+      __ movp(rax, Operand(rbp, kStringStartMinusOne));
+
+      if (global_with_zero_length_check()) {
+        // Special case for zero-length matches.
+        // rdx: capture start index
+        __ cmpp(rdi, rdx);
+        // Not a zero-length match, restart.
+        __ j(not_equal, &load_char_start_regexp);
+        // rdi (offset from the end) is zero if we already reached the end.
+        __ testp(rdi, rdi);
+        __ j(zero, &exit_label_, Label::kNear);
+        // Advance current position after a zero-length match.
+        if (mode_ == UC16) {
+          __ addq(rdi, Immediate(2));
+        } else {
+          __ incq(rdi);
+        }
+      }
+
+      __ jmp(&load_char_start_regexp);
+    } else {
+      __ movp(rax, Immediate(SUCCESS));
+    }
+  }
+
+  __ bind(&exit_label_);
+  if (global()) {
+    // Return the number of successful captures.
+    __ movp(rax, Operand(rbp, kSuccessfulCaptures));
+  }
+
+  __ bind(&return_rax);
+#ifdef _WIN64
+  // Restore callee save registers.
+  __ leap(rsp, Operand(rbp, kLastCalleeSaveRegister));
+  __ popq(rbx);
+  __ popq(rdi);
+  __ popq(rsi);
+  // Stack now at rbp.
+#else
+  // Restore callee save register.
+  __ movp(rbx, Operand(rbp, kBackup_rbx));
+  // Skip rsp to rbp.
+  __ movp(rsp, rbp);
+#endif
+  // Exit function frame, restore previous one.
+  __ popq(rbp);
+  __ ret(0);
+
+  // Backtrack code (branch target for conditional backtracks).
+  if (backtrack_label_.is_linked()) {
+    __ bind(&backtrack_label_);
+    Backtrack();
+  }
+
+  Label exit_with_exception;
+
+  // Preempt-code
+  if (check_preempt_label_.is_linked()) {
+    SafeCallTarget(&check_preempt_label_);
+
+    __ pushq(backtrack_stackpointer());
+    __ pushq(rdi);
+
+    CallCheckStackGuardState();
+    __ testp(rax, rax);
+    // If returning non-zero, we should end execution with the given
+    // result as return value.
+    __ j(not_zero, &return_rax);
+
+    // Restore registers.
+    __ Move(code_object_pointer(), masm_.CodeObject());
+    __ popq(rdi);
+    __ popq(backtrack_stackpointer());
+    // String might have moved: Reload esi from frame.
+    __ movp(rsi, Operand(rbp, kInputEnd));
+    SafeReturn();
+  }
+
+  // Backtrack stack overflow code.
+  if (stack_overflow_label_.is_linked()) {
+    SafeCallTarget(&stack_overflow_label_);
+    // Reached if the backtrack-stack limit has been hit.
+
+    Label grow_failed;
+    // Save registers before calling C function
+#ifndef _WIN64
+    // Callee-save in Microsoft 64-bit ABI, but not in AMD64 ABI.
+    __ pushq(rsi);
+    __ pushq(rdi);
+#endif
+
+    // Call GrowStack(backtrack_stackpointer())
+    static const int num_arguments = 3;
+    __ PrepareCallCFunction(num_arguments);
+#ifdef _WIN64
+    // Microsoft passes parameters in rcx, rdx, r8.
+    // First argument, backtrack stackpointer, is already in rcx.
+    __ leap(rdx, Operand(rbp, kStackHighEnd));  // Second argument
+    __ LoadAddress(r8, ExternalReference::isolate_address(isolate()));
+#else
+    // AMD64 ABI passes parameters in rdi, rsi, rdx.
+    __ movp(rdi, backtrack_stackpointer());   // First argument.
+    __ leap(rsi, Operand(rbp, kStackHighEnd));  // Second argument.
+    __ LoadAddress(rdx, ExternalReference::isolate_address(isolate()));
+#endif
+    ExternalReference grow_stack =
+        ExternalReference::re_grow_stack(isolate());
+    __ CallCFunction(grow_stack, num_arguments);
+    // If return NULL, we have failed to grow the stack, and
+    // must exit with a stack-overflow exception.
+    __ testp(rax, rax);
+    __ j(equal, &exit_with_exception);
+    // Otherwise use return value as new stack pointer.
+    __ movp(backtrack_stackpointer(), rax);
+    // Restore saved registers and continue.
+    __ Move(code_object_pointer(), masm_.CodeObject());
+#ifndef _WIN64
+    __ popq(rdi);
+    __ popq(rsi);
+#endif
+    SafeReturn();
+  }
+
+  if (exit_with_exception.is_linked()) {
+    // If any of the code above needed to exit with an exception.
+    __ bind(&exit_with_exception);
+    // Exit with Result EXCEPTION(-1) to signal thrown exception.
+    __ Set(rax, EXCEPTION);
+    __ jmp(&return_rax);
+  }
+
+  FixupCodeRelativePositions();
+
+  CodeDesc code_desc;
+  masm_.GetCode(&code_desc);
+  Isolate* isolate = this->isolate();
+  Handle<Code> code = isolate->factory()->NewCode(
+      code_desc, Code::ComputeFlags(Code::REGEXP),
+      masm_.CodeObject());
+  PROFILE(isolate, RegExpCodeCreateEvent(*code, *source));
+  return Handle<HeapObject>::cast(code);
+}
+
+
+void RegExpMacroAssemblerX64::GoTo(Label* to) {
+  BranchOrBacktrack(no_condition, to);
+}
+
+
+void RegExpMacroAssemblerX64::IfRegisterGE(int reg,
+                                           int comparand,
+                                           Label* if_ge) {
+  __ cmpp(register_location(reg), Immediate(comparand));
+  BranchOrBacktrack(greater_equal, if_ge);
+}
+
+
+void RegExpMacroAssemblerX64::IfRegisterLT(int reg,
+                                           int comparand,
+                                           Label* if_lt) {
+  __ cmpp(register_location(reg), Immediate(comparand));
+  BranchOrBacktrack(less, if_lt);
+}
+
+
+void RegExpMacroAssemblerX64::IfRegisterEqPos(int reg,
+                                              Label* if_eq) {
+  __ cmpp(rdi, register_location(reg));
+  BranchOrBacktrack(equal, if_eq);
+}
+
+
+RegExpMacroAssembler::IrregexpImplementation
+    RegExpMacroAssemblerX64::Implementation() {
+  return kX64Implementation;
+}
+
+
+void RegExpMacroAssemblerX64::LoadCurrentCharacter(int cp_offset,
+                                                   Label* on_end_of_input,
+                                                   bool check_bounds,
+                                                   int characters) {
+  DCHECK(cp_offset < (1<<30));  // Be sane! (And ensure negation works)
+  if (check_bounds) {
+    if (cp_offset >= 0) {
+      CheckPosition(cp_offset + characters - 1, on_end_of_input);
+    } else {
+      CheckPosition(cp_offset, on_end_of_input);
+    }
+  }
+  LoadCurrentCharacterUnchecked(cp_offset, characters);
+}
+
+
+void RegExpMacroAssemblerX64::PopCurrentPosition() {
+  Pop(rdi);
+}
+
+
+void RegExpMacroAssemblerX64::PopRegister(int register_index) {
+  Pop(rax);
+  __ movp(register_location(register_index), rax);
+}
+
+
+void RegExpMacroAssemblerX64::PushBacktrack(Label* label) {
+  Push(label);
+  CheckStackLimit();
+}
+
+
+void RegExpMacroAssemblerX64::PushCurrentPosition() {
+  Push(rdi);
+}
+
+
+void RegExpMacroAssemblerX64::PushRegister(int register_index,
+                                           StackCheckFlag check_stack_limit) {
+  __ movp(rax, register_location(register_index));
+  Push(rax);
+  if (check_stack_limit) CheckStackLimit();
+}
+
+
+STATIC_ASSERT(kPointerSize == kInt64Size || kPointerSize == kInt32Size);
+
+
+void RegExpMacroAssemblerX64::ReadCurrentPositionFromRegister(int reg) {
+  if (kPointerSize == kInt64Size) {
+    __ movq(rdi, register_location(reg));
+  } else {
+    // Need sign extension for x32 as rdi might be used as an index register.
+    __ movsxlq(rdi, register_location(reg));
+  }
+}
+
+
+void RegExpMacroAssemblerX64::ReadPositionFromRegister(Register dst, int reg) {
+  if (kPointerSize == kInt64Size) {
+    __ movq(dst, register_location(reg));
+  } else {
+    // Need sign extension for x32 as dst might be used as an index register.
+    __ movsxlq(dst, register_location(reg));
+  }
+}
+
+
+void RegExpMacroAssemblerX64::ReadStackPointerFromRegister(int reg) {
+  __ movp(backtrack_stackpointer(), register_location(reg));
+  __ addp(backtrack_stackpointer(), Operand(rbp, kStackHighEnd));
+}
+
+
+void RegExpMacroAssemblerX64::SetCurrentPositionFromEnd(int by) {
+  Label after_position;
+  __ cmpp(rdi, Immediate(-by * char_size()));
+  __ j(greater_equal, &after_position, Label::kNear);
+  __ movq(rdi, Immediate(-by * char_size()));
+  // On RegExp code entry (where this operation is used), the character before
+  // the current position is expected to be already loaded.
+  // We have advanced the position, so it's safe to read backwards.
+  LoadCurrentCharacterUnchecked(-1, 1);
+  __ bind(&after_position);
+}
+
+
+void RegExpMacroAssemblerX64::SetRegister(int register_index, int to) {
+  DCHECK(register_index >= num_saved_registers_);  // Reserved for positions!
+  __ movp(register_location(register_index), Immediate(to));
+}
+
+
+bool RegExpMacroAssemblerX64::Succeed() {
+  __ jmp(&success_label_);
+  return global();
+}
+
+
+void RegExpMacroAssemblerX64::WriteCurrentPositionToRegister(int reg,
+                                                             int cp_offset) {
+  if (cp_offset == 0) {
+    __ movp(register_location(reg), rdi);
+  } else {
+    __ leap(rax, Operand(rdi, cp_offset * char_size()));
+    __ movp(register_location(reg), rax);
+  }
+}
+
+
+void RegExpMacroAssemblerX64::ClearRegisters(int reg_from, int reg_to) {
+  DCHECK(reg_from <= reg_to);
+  __ movp(rax, Operand(rbp, kStringStartMinusOne));
+  for (int reg = reg_from; reg <= reg_to; reg++) {
+    __ movp(register_location(reg), rax);
+  }
+}
+
+
+void RegExpMacroAssemblerX64::WriteStackPointerToRegister(int reg) {
+  __ movp(rax, backtrack_stackpointer());
+  __ subp(rax, Operand(rbp, kStackHighEnd));
+  __ movp(register_location(reg), rax);
+}
+
+
+// Private methods:
+
+void RegExpMacroAssemblerX64::CallCheckStackGuardState() {
+  // This function call preserves no register values. Caller should
+  // store anything volatile in a C call or overwritten by this function.
+  static const int num_arguments = 3;
+  __ PrepareCallCFunction(num_arguments);
+#ifdef _WIN64
+  // Second argument: Code* of self. (Do this before overwriting r8).
+  __ movp(rdx, code_object_pointer());
+  // Third argument: RegExp code frame pointer.
+  __ movp(r8, rbp);
+  // First argument: Next address on the stack (will be address of
+  // return address).
+  __ leap(rcx, Operand(rsp, -kPointerSize));
+#else
+  // Third argument: RegExp code frame pointer.
+  __ movp(rdx, rbp);
+  // Second argument: Code* of self.
+  __ movp(rsi, code_object_pointer());
+  // First argument: Next address on the stack (will be address of
+  // return address).
+  __ leap(rdi, Operand(rsp, -kRegisterSize));
+#endif
+  ExternalReference stack_check =
+      ExternalReference::re_check_stack_guard_state(isolate());
+  __ CallCFunction(stack_check, num_arguments);
+}
+
+
+// Helper function for reading a value out of a stack frame.
+template <typename T>
+static T& frame_entry(Address re_frame, int frame_offset) {
+  return reinterpret_cast<T&>(Memory::int32_at(re_frame + frame_offset));
+}
+
+
+template <typename T>
+static T* frame_entry_address(Address re_frame, int frame_offset) {
+  return reinterpret_cast<T*>(re_frame + frame_offset);
+}
+
+
+int RegExpMacroAssemblerX64::CheckStackGuardState(Address* return_address,
+                                                  Code* re_code,
+                                                  Address re_frame) {
+  return NativeRegExpMacroAssembler::CheckStackGuardState(
+      frame_entry<Isolate*>(re_frame, kIsolate),
+      frame_entry<int>(re_frame, kStartIndex),
+      frame_entry<int>(re_frame, kDirectCall) == 1, return_address, re_code,
+      frame_entry_address<String*>(re_frame, kInputString),
+      frame_entry_address<const byte*>(re_frame, kInputStart),
+      frame_entry_address<const byte*>(re_frame, kInputEnd));
+}
+
+
+Operand RegExpMacroAssemblerX64::register_location(int register_index) {
+  DCHECK(register_index < (1<<30));
+  if (num_registers_ <= register_index) {
+    num_registers_ = register_index + 1;
+  }
+  return Operand(rbp, kRegisterZero - register_index * kPointerSize);
+}
+
+
+void RegExpMacroAssemblerX64::CheckPosition(int cp_offset,
+                                            Label* on_outside_input) {
+  if (cp_offset >= 0) {
+    __ cmpl(rdi, Immediate(-cp_offset * char_size()));
+    BranchOrBacktrack(greater_equal, on_outside_input);
+  } else {
+    __ leap(rax, Operand(rdi, cp_offset * char_size()));
+    __ cmpp(rax, Operand(rbp, kStringStartMinusOne));
+    BranchOrBacktrack(less_equal, on_outside_input);
+  }
+}
+
+
+void RegExpMacroAssemblerX64::BranchOrBacktrack(Condition condition,
+                                                Label* to) {
+  if (condition < 0) {  // No condition
+    if (to == NULL) {
+      Backtrack();
+      return;
+    }
+    __ jmp(to);
+    return;
+  }
+  if (to == NULL) {
+    __ j(condition, &backtrack_label_);
+    return;
+  }
+  __ j(condition, to);
+}
+
+
+void RegExpMacroAssemblerX64::SafeCall(Label* to) {
+  __ call(to);
+}
+
+
+void RegExpMacroAssemblerX64::SafeCallTarget(Label* label) {
+  __ bind(label);
+  __ subp(Operand(rsp, 0), code_object_pointer());
+}
+
+
+void RegExpMacroAssemblerX64::SafeReturn() {
+  __ addp(Operand(rsp, 0), code_object_pointer());
+  __ ret(0);
+}
+
+
+void RegExpMacroAssemblerX64::Push(Register source) {
+  DCHECK(!source.is(backtrack_stackpointer()));
+  // Notice: This updates flags, unlike normal Push.
+  __ subp(backtrack_stackpointer(), Immediate(kIntSize));
+  __ movl(Operand(backtrack_stackpointer(), 0), source);
+}
+
+
+void RegExpMacroAssemblerX64::Push(Immediate value) {
+  // Notice: This updates flags, unlike normal Push.
+  __ subp(backtrack_stackpointer(), Immediate(kIntSize));
+  __ movl(Operand(backtrack_stackpointer(), 0), value);
+}
+
+
+void RegExpMacroAssemblerX64::FixupCodeRelativePositions() {
+  for (int i = 0, n = code_relative_fixup_positions_.length(); i < n; i++) {
+    int position = code_relative_fixup_positions_[i];
+    // The position succeeds a relative label offset from position.
+    // Patch the relative offset to be relative to the Code object pointer
+    // instead.
+    int patch_position = position - kIntSize;
+    int offset = masm_.long_at(patch_position);
+    masm_.long_at_put(patch_position,
+                       offset
+                       + position
+                       + Code::kHeaderSize
+                       - kHeapObjectTag);
+  }
+  code_relative_fixup_positions_.Clear();
+}
+
+
+void RegExpMacroAssemblerX64::Push(Label* backtrack_target) {
+  __ subp(backtrack_stackpointer(), Immediate(kIntSize));
+  __ movl(Operand(backtrack_stackpointer(), 0), backtrack_target);
+  MarkPositionForCodeRelativeFixup();
+}
+
+
+void RegExpMacroAssemblerX64::Pop(Register target) {
+  DCHECK(!target.is(backtrack_stackpointer()));
+  __ movsxlq(target, Operand(backtrack_stackpointer(), 0));
+  // Notice: This updates flags, unlike normal Pop.
+  __ addp(backtrack_stackpointer(), Immediate(kIntSize));
+}
+
+
+void RegExpMacroAssemblerX64::Drop() {
+  __ addp(backtrack_stackpointer(), Immediate(kIntSize));
+}
+
+
+void RegExpMacroAssemblerX64::CheckPreemption() {
+  // Check for preemption.
+  Label no_preempt;
+  ExternalReference stack_limit =
+      ExternalReference::address_of_stack_limit(isolate());
+  __ load_rax(stack_limit);
+  __ cmpp(rsp, rax);
+  __ j(above, &no_preempt);
+
+  SafeCall(&check_preempt_label_);
+
+  __ bind(&no_preempt);
+}
+
+
+void RegExpMacroAssemblerX64::CheckStackLimit() {
+  Label no_stack_overflow;
+  ExternalReference stack_limit =
+      ExternalReference::address_of_regexp_stack_limit(isolate());
+  __ load_rax(stack_limit);
+  __ cmpp(backtrack_stackpointer(), rax);
+  __ j(above, &no_stack_overflow);
+
+  SafeCall(&stack_overflow_label_);
+
+  __ bind(&no_stack_overflow);
+}
+
+
+void RegExpMacroAssemblerX64::LoadCurrentCharacterUnchecked(int cp_offset,
+                                                            int characters) {
+  if (mode_ == LATIN1) {
+    if (characters == 4) {
+      __ movl(current_character(), Operand(rsi, rdi, times_1, cp_offset));
+    } else if (characters == 2) {
+      __ movzxwl(current_character(), Operand(rsi, rdi, times_1, cp_offset));
+    } else {
+      DCHECK(characters == 1);
+      __ movzxbl(current_character(), Operand(rsi, rdi, times_1, cp_offset));
+    }
+  } else {
+    DCHECK(mode_ == UC16);
+    if (characters == 2) {
+      __ movl(current_character(),
+              Operand(rsi, rdi, times_1, cp_offset * sizeof(uc16)));
+    } else {
+      DCHECK(characters == 1);
+      __ movzxwl(current_character(),
+                 Operand(rsi, rdi, times_1, cp_offset * sizeof(uc16)));
+    }
+  }
+}
+
+#undef __
+
+#endif  // V8_INTERPRETED_REGEXP
+
+}  // namespace internal
+}  // namespace v8
+
+#endif  // V8_TARGET_ARCH_X64