[regexp] Port RegExpExecStub to CSA (mostly)

src/x64/code-stubs-x64.cc

 // Copyright 2013 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/api-arguments.h"
 #include "src/bootstrapper.h"
 #include "src/code-stubs.h"
 #include "src/codegen.h"
@@ skipping 333 matching lines @@
                      2);
   }
   // Return value is in xmm0.
   __ Movsd(double_result, xmm0);
 
   __ bind(&done);
   __ ret(0);
 }
 
 void RegExpExecStub::Generate(MacroAssembler* masm) {
-  // Just jump directly to runtime if native RegExp is not selected at compile
-  // time or if regexp entry in generated code is turned off runtime switch or
-  // at compilation.
 #ifdef V8_INTERPRETED_REGEXP
-  __ TailCallRuntime(Runtime::kRegExpExec);
+  // This case is handled prior to the RegExpExecStub call.
+  __ Abort(kUnexpectedRegExpExecCall);
 #else  // V8_INTERPRETED_REGEXP
-
-  // Stack frame on entry.
-  //  rsp[0]  : return address
-  //  rsp[8]  : last_match_info (expected JSArray)
-  //  rsp[16] : previous index
-  //  rsp[24] : subject string
-  //  rsp[32] : JSRegExp object
-
-  enum RegExpExecStubArgumentIndices {
-    JS_REG_EXP_OBJECT_ARGUMENT_INDEX,
-    SUBJECT_STRING_ARGUMENT_INDEX,
-    PREVIOUS_INDEX_ARGUMENT_INDEX,
-    LAST_MATCH_INFO_ARGUMENT_INDEX,
-    REG_EXP_EXEC_ARGUMENT_COUNT
-  };
-
-  StackArgumentsAccessor args(rsp, REG_EXP_EXEC_ARGUMENT_COUNT,
-                              ARGUMENTS_DONT_CONTAIN_RECEIVER);
-  Label runtime;
-  // Ensure that a RegExp stack is allocated.
-  ExternalReference address_of_regexp_stack_memory_address =
-      ExternalReference::address_of_regexp_stack_memory_address(isolate());
-  ExternalReference address_of_regexp_stack_memory_size =
-      ExternalReference::address_of_regexp_stack_memory_size(isolate());
-  __ Load(kScratchRegister, address_of_regexp_stack_memory_size);
-  __ testp(kScratchRegister, kScratchRegister);
-  __ j(zero, &runtime);
-
-  // Check that the first argument is a JSRegExp object.
-  __ movp(rax, args.GetArgumentOperand(JS_REG_EXP_OBJECT_ARGUMENT_INDEX));
-  __ JumpIfSmi(rax, &runtime);
-  __ CmpObjectType(rax, JS_REGEXP_TYPE, kScratchRegister);
-  __ j(not_equal, &runtime);
-
-  // Check that the RegExp has been compiled (data contains a fixed array).
-  __ movp(rax, FieldOperand(rax, JSRegExp::kDataOffset));
-  if (FLAG_debug_code) {
-    Condition is_smi = masm->CheckSmi(rax);
-    __ Check(NegateCondition(is_smi),
-        kUnexpectedTypeForRegExpDataFixedArrayExpected);
-    __ CmpObjectType(rax, FIXED_ARRAY_TYPE, kScratchRegister);
-    __ Check(equal, kUnexpectedTypeForRegExpDataFixedArrayExpected);
-  }
-
-  // rax: RegExp data (FixedArray)
-  // Check the type of the RegExp. Only continue if type is JSRegExp::IRREGEXP.
-  __ SmiToInteger32(rbx, FieldOperand(rax, JSRegExp::kDataTagOffset));
-  __ cmpl(rbx, Immediate(JSRegExp::IRREGEXP));
-  __ j(not_equal, &runtime);
-
-  // rax: RegExp data (FixedArray)
-  // Check that the number of captures fit in the static offsets vector buffer.
-  __ SmiToInteger32(rdx,
-                    FieldOperand(rax, JSRegExp::kIrregexpCaptureCountOffset));
-  // Check (number_of_captures + 1) * 2 <= offsets vector size
-  // Or              number_of_captures <= offsets vector size / 2 - 1
-  STATIC_ASSERT(Isolate::kJSRegexpStaticOffsetsVectorSize >= 2);
-  __ cmpl(rdx, Immediate(Isolate::kJSRegexpStaticOffsetsVectorSize / 2 - 1));
-  __ j(above, &runtime);
-
-  // Reset offset for possibly sliced string.
-  __ Set(r14, 0);
-  __ movp(rdi, args.GetArgumentOperand(SUBJECT_STRING_ARGUMENT_INDEX));
-  __ JumpIfSmi(rdi, &runtime);
-  __ movp(r15, rdi);  // Make a copy of the original subject string.
-  // rax: RegExp data (FixedArray)
-  // rdi: subject string
-  // r15: subject string
-  // Handle subject string according to its encoding and representation:
-  // (1) Sequential two byte?  If yes, go to (9).
-  // (2) Sequential one byte?  If yes, go to (5).
-  // (3) Sequential or cons?  If not, go to (6).
-  // (4) Cons string.  If the string is flat, replace subject with first string
-  //     and go to (1). Otherwise bail out to runtime.
-  // (5) One byte sequential.  Load regexp code for one byte.
-  // (E) Carry on.
-  /// [...]
-
-  // Deferred code at the end of the stub:
-  // (6) Long external string?  If not, go to (10).
-  // (7) External string.  Make it, offset-wise, look like a sequential string.
-  // (8) Is the external string one byte?  If yes, go to (5).
-  // (9) Two byte sequential.  Load regexp code for two byte. Go to (E).
-  // (10) Short external string or not a string?  If yes, bail out to runtime.
-  // (11) Sliced or thin string.  Replace subject with parent. Go to (1).
-
-  Label seq_one_byte_string /* 5 */, seq_two_byte_string /* 9 */,
-      external_string /* 7 */, check_underlying /* 1 */,
-      not_seq_nor_cons /* 6 */, check_code /* E */, not_long_external /* 10 */;
-
-  __ bind(&check_underlying);
-  __ movp(rbx, FieldOperand(rdi, HeapObject::kMapOffset));
-  __ movzxbl(rbx, FieldOperand(rbx, Map::kInstanceTypeOffset));
-
-  // (1) Sequential two byte?  If yes, go to (9).
-  __ andb(rbx, Immediate(kIsNotStringMask |
-                         kStringRepresentationMask |
-                         kStringEncodingMask |
-                         kShortExternalStringMask));
-  STATIC_ASSERT((kStringTag | kSeqStringTag | kTwoByteStringTag) == 0);
-  __ j(zero, &seq_two_byte_string);  // Go to (9).
-
-  // (2) Sequential one byte?  If yes, go to (5).
-  // Any other sequential string must be one byte.
-  __ andb(rbx, Immediate(kIsNotStringMask |
-                         kStringRepresentationMask |
-                         kShortExternalStringMask));
-  __ j(zero, &seq_one_byte_string, Label::kNear);  // Go to (5).
-
-  // (3) Sequential or cons?  If not, go to (6).
-  // We check whether the subject string is a cons, since sequential strings
-  // have already been covered.
-  STATIC_ASSERT(kConsStringTag < kExternalStringTag);
-  STATIC_ASSERT(kSlicedStringTag > kExternalStringTag);
-  STATIC_ASSERT(kThinStringTag > kExternalStringTag);
-  STATIC_ASSERT(kIsNotStringMask > kExternalStringTag);
-  STATIC_ASSERT(kShortExternalStringTag > kExternalStringTag);
-  __ cmpp(rbx, Immediate(kExternalStringTag));
-  __ j(greater_equal, &not_seq_nor_cons);  // Go to (6).
-
-  // (4) Cons string.  Check that it's flat.
-  // Replace subject with first string and reload instance type.
-  __ CompareRoot(FieldOperand(rdi, ConsString::kSecondOffset),
-                 Heap::kempty_stringRootIndex);
-  __ j(not_equal, &runtime);
-  __ movp(rdi, FieldOperand(rdi, ConsString::kFirstOffset));
-  __ jmp(&check_underlying);
-
-  // (5) One byte sequential.  Load regexp code for one byte.
-  __ bind(&seq_one_byte_string);
-  // rax: RegExp data (FixedArray)
-  __ movp(r11, FieldOperand(rax, JSRegExp::kDataOneByteCodeOffset));
-  __ Set(rcx, 1);  // Type is one byte.
-
-  // (E) Carry on.  String handling is done.
-  __ bind(&check_code);
-  // r11: irregexp code
-  // Check that the irregexp code has been generated for the actual string
-  // encoding. If it has, the field contains a code object otherwise it contains
-  // smi (code flushing support)
-  __ JumpIfSmi(r11, &runtime);
-
-  // rdi: sequential subject string (or look-alike, external string)
-  // r15: original subject string
-  // rcx: encoding of subject string (1 if one_byte, 0 if two_byte);
-  // r11: code
-  // Load used arguments before starting to push arguments for call to native
-  // RegExp code to avoid handling changing stack height.
-  // We have to use r15 instead of rdi to load the length because rdi might
-  // have been only made to look like a sequential string when it actually
-  // is an external string.
-  __ movp(rbx, args.GetArgumentOperand(PREVIOUS_INDEX_ARGUMENT_INDEX));
-  __ JumpIfNotSmi(rbx, &runtime);
-  __ SmiCompare(rbx, FieldOperand(r15, String::kLengthOffset));
-  __ j(above_equal, &runtime);
-  __ SmiToInteger64(rbx, rbx);
-
-  // rdi: subject string
-  // rbx: previous index
-  // rcx: encoding of subject string (1 if one_byte 0 if two_byte);
-  // r11: code
-  // All checks done. Now push arguments for native regexp code.
-  Counters* counters = isolate()->counters();
-  __ IncrementCounter(counters->regexp_entry_native(), 1);
-
   // Isolates: note we add an additional parameter here (isolate pointer).
   static const int kRegExpExecuteArguments = 9;
   int argument_slots_on_stack =
       masm->ArgumentStackSlotsForCFunctionCall(kRegExpExecuteArguments);
   __ EnterApiExitFrame(argument_slots_on_stack);
 
   // Argument 9: Pass current isolate address.
   __ LoadAddress(kScratchRegister,
                  ExternalReference::isolate_address(isolate()));
   __ movq(Operand(rsp, (argument_slots_on_stack - 1) * kRegisterSize),
           kScratchRegister);
 
   // Argument 8: Indicate that this is a direct call from JavaScript.
   __ movq(Operand(rsp, (argument_slots_on_stack - 2) * kRegisterSize),
           Immediate(1));
 
   // Argument 7: Start (high end) of backtracking stack memory area.
+  ExternalReference address_of_regexp_stack_memory_address =
+      ExternalReference::address_of_regexp_stack_memory_address(isolate());
+  ExternalReference address_of_regexp_stack_memory_size =
+      ExternalReference::address_of_regexp_stack_memory_size(isolate());
   __ Move(kScratchRegister, address_of_regexp_stack_memory_address);
-  __ movp(r9, Operand(kScratchRegister, 0));
+  __ movp(r12, Operand(kScratchRegister, 0));
   __ Move(kScratchRegister, address_of_regexp_stack_memory_size);
-  __ addp(r9, Operand(kScratchRegister, 0));
-  __ movq(Operand(rsp, (argument_slots_on_stack - 3) * kRegisterSize), r9);
+  __ addp(r12, Operand(kScratchRegister, 0));
+  __ movq(Operand(rsp, (argument_slots_on_stack - 3) * kRegisterSize), r12);
 
   // Argument 6: Set the number of capture registers to zero to force global
   // regexps to behave as non-global.  This does not affect non-global regexps.
   // Argument 6 is passed in r9 on Linux and on the stack on Windows.
 #ifdef _WIN64
   __ movq(Operand(rsp, (argument_slots_on_stack - 4) * kRegisterSize),
           Immediate(0));
 #else
   __ Set(r9, 0);
 #endif
 
   // Argument 5: static offsets vector buffer.
+  // Argument 5 passed in r8 on Linux and on the stack on Windows.
+#ifdef _WIN64
+  __ LoadAddress(
+      r12, ExternalReference::address_of_static_offsets_vector(isolate()));
+  __ movq(Operand(rsp, (argument_slots_on_stack - 5) * kRegisterSize), r12);
+#else  // _WIN64
   __ LoadAddress(
       r8, ExternalReference::address_of_static_offsets_vector(isolate()));
-  // Argument 5 passed in r8 on Linux and on the stack on Windows.
-#ifdef _WIN64
-  __ movq(Operand(rsp, (argument_slots_on_stack - 5) * kRegisterSize), r8);
 #endif
 
-  // rdi: subject string
-  // rbx: previous index
-  // rcx: encoding of subject string (1 if one_byte 0 if two_byte);
-  // r11: code
-  // r14: slice offset
-  // r15: original subject string
-
   // Argument 2: Previous index.
-  __ movp(arg_reg_2, rbx);
+  // TODO(jgruber): Ideally, LastIndexRegister would already equal arg_reg_2,
+  // but that makes register allocation fail.
+  __ movp(arg_reg_2, RegExpExecDescriptor::LastIndexRegister());
 
   // Argument 4: End of string data
   // Argument 3: Start of string data
-  Label setup_two_byte, setup_rest, got_length, length_not_from_slice;
-  // Prepare start and end index of the input.
-  // Load the length from the original sliced string if that is the case.
-  __ addp(rbx, r14);
-  __ SmiToInteger32(arg_reg_3, FieldOperand(r15, String::kLengthOffset));
-  __ addp(r14, arg_reg_3);  // Using arg3 as scratch.
-
-  // rbx: start index of the input
-  // r14: end index of the input
-  // r15: original subject string
-  __ testb(rcx, rcx);  // Last use of rcx as encoding of subject string.
-  __ j(zero, &setup_two_byte, Label::kNear);
-  __ leap(arg_reg_4,
-         FieldOperand(rdi, r14, times_1, SeqOneByteString::kHeaderSize));
-  __ leap(arg_reg_3,
-         FieldOperand(rdi, rbx, times_1, SeqOneByteString::kHeaderSize));
-  __ jmp(&setup_rest, Label::kNear);
-  __ bind(&setup_two_byte);
-  __ leap(arg_reg_4,
-         FieldOperand(rdi, r14, times_2, SeqTwoByteString::kHeaderSize));
-  __ leap(arg_reg_3,
-         FieldOperand(rdi, rbx, times_2, SeqTwoByteString::kHeaderSize));
-  __ bind(&setup_rest);
+  CHECK(arg_reg_4.is(RegExpExecDescriptor::StringEndRegister()));
+  CHECK(arg_reg_3.is(RegExpExecDescriptor::StringStartRegister()));
 
   // Argument 1: Original subject string.
-  // The original subject is in the previous stack frame. Therefore we have to
-  // use rbp, which points exactly to one pointer size below the previous rsp.
-  // (Because creating a new stack frame pushes the previous rbp onto the stack
-  // and thereby moves up rsp by one kPointerSize.)
-  __ movp(arg_reg_1, r15);
+  CHECK(arg_reg_1.is(RegExpExecDescriptor::StringRegister()));
 
-  // Locate the code entry and call it.
-  __ addp(r11, Immediate(Code::kHeaderSize - kHeapObjectTag));
-  __ call(r11);
+  __ addp(RegExpExecDescriptor::CodeRegister(),
+          Immediate(Code::kHeaderSize - kHeapObjectTag));
+  __ call(RegExpExecDescriptor::CodeRegister());
 
   __ LeaveApiExitFrame(true);
 
-  // Check the result.
-  Label success;
-  Label exception;
-  __ cmpl(rax, Immediate(1));
-  // We expect exactly one result since we force the called regexp to behave
-  // as non-global.
-  __ j(equal, &success, Label::kNear);
-  __ cmpl(rax, Immediate(NativeRegExpMacroAssembler::EXCEPTION));
-  __ j(equal, &exception);
-  __ cmpl(rax, Immediate(NativeRegExpMacroAssembler::FAILURE));
-  // If none of the above, it can only be retry.
-  // Handle that in the runtime system.
-  __ j(not_equal, &runtime);
-
-  // For failure return null.
-  __ LoadRoot(rax, Heap::kNullValueRootIndex);
-  __ ret(REG_EXP_EXEC_ARGUMENT_COUNT * kPointerSize);
-
-  // Load RegExp data.
-  __ bind(&success);
-  __ movp(rax, args.GetArgumentOperand(JS_REG_EXP_OBJECT_ARGUMENT_INDEX));
-  __ movp(rcx, FieldOperand(rax, JSRegExp::kDataOffset));
-  __ SmiToInteger32(rax,
-                    FieldOperand(rcx, JSRegExp::kIrregexpCaptureCountOffset));
-  // Calculate number of capture registers (number_of_captures + 1) * 2.
-  __ leal(rdx, Operand(rax, rax, times_1, 2));
-
-  // rdx: Number of capture registers
-  // Check that the last match info is a FixedArray.
-  __ movp(rbx, args.GetArgumentOperand(LAST_MATCH_INFO_ARGUMENT_INDEX));
-  __ JumpIfSmi(rbx, &runtime);
-  // Check that the object has fast elements.
-  __ movp(rax, FieldOperand(rbx, HeapObject::kMapOffset));
-  __ CompareRoot(rax, Heap::kFixedArrayMapRootIndex);
-  __ j(not_equal, &runtime);
-  // Check that the last match info has space for the capture registers and the
-  // additional information. Ensure no overflow in add.
-  STATIC_ASSERT(FixedArray::kMaxLength < kMaxInt - FixedArray::kLengthOffset);
-  __ SmiToInteger32(rax, FieldOperand(rbx, FixedArray::kLengthOffset));
-  __ subl(rax, Immediate(RegExpMatchInfo::kLastMatchOverhead));
-  __ cmpl(rdx, rax);
-  __ j(greater, &runtime);
-
-  // rbx: last_match_info (FixedArray)
-  // rdx: number of capture registers
-  // Store the capture count.
-  __ Integer32ToSmi(kScratchRegister, rdx);
-  __ movp(FieldOperand(rbx, RegExpMatchInfo::kNumberOfCapturesOffset),
-          kScratchRegister);
-  // Store last subject and last input.
-  __ movp(rax, args.GetArgumentOperand(SUBJECT_STRING_ARGUMENT_INDEX));
-  __ movp(FieldOperand(rbx, RegExpMatchInfo::kLastSubjectOffset), rax);
-  __ movp(rcx, rax);
-  __ RecordWriteField(rbx, RegExpMatchInfo::kLastSubjectOffset, rax, rdi,
-                      kDontSaveFPRegs);
-  __ movp(rax, rcx);
-  __ movp(FieldOperand(rbx, RegExpMatchInfo::kLastInputOffset), rax);
-  __ RecordWriteField(rbx, RegExpMatchInfo::kLastInputOffset, rax, rdi,
-                      kDontSaveFPRegs);
-
-  // Get the static offsets vector filled by the native regexp code.
-  __ LoadAddress(
-      rcx, ExternalReference::address_of_static_offsets_vector(isolate()));
-
-  // rbx: last_match_info (FixedArray)
-  // rcx: offsets vector
-  // rdx: number of capture registers
-  Label next_capture, done;
-  // Capture register counter starts from number of capture registers and
-  // counts down until wrapping after zero.
-  __ bind(&next_capture);
-  __ subp(rdx, Immediate(1));
-  __ j(negative, &done, Label::kNear);
-  // Read the value from the static offsets vector buffer and make it a smi.
-  __ movl(rdi, Operand(rcx, rdx, times_int_size, 0));
-  __ Integer32ToSmi(rdi, rdi);
-  // Store the smi value in the last match info.
-  __ movp(FieldOperand(rbx, rdx, times_pointer_size,
-                       RegExpMatchInfo::kFirstCaptureOffset),
-          rdi);
-  __ jmp(&next_capture);
-  __ bind(&done);
-
-  // Return last match info.
-  __ movp(rax, rbx);
-  __ ret(REG_EXP_EXEC_ARGUMENT_COUNT * kPointerSize);
-
-  __ bind(&exception);
-  // Result must now be exception. If there is no pending exception already a
-  // stack overflow (on the backtrack stack) was detected in RegExp code but
-  // haven't created the exception yet. Handle that in the runtime system.
-  // TODO(592): Rerunning the RegExp to get the stack overflow exception.
-  ExternalReference pending_exception_address(
-      Isolate::kPendingExceptionAddress, isolate());
-  Operand pending_exception_operand =
-      masm->ExternalOperand(pending_exception_address, rbx);
-  __ movp(rax, pending_exception_operand);
-  __ LoadRoot(rdx, Heap::kTheHoleValueRootIndex);
-  __ cmpp(rax, rdx);
-  __ j(equal, &runtime);
-
-  // For exception, throw the exception again.
-  __ TailCallRuntime(Runtime::kRegExpExecReThrow);
-
-  // Do the runtime call to execute the regexp.
-  __ bind(&runtime);
-  __ TailCallRuntime(Runtime::kRegExpExec);
-
-  // Deferred code for string handling.
-  // (6) Long external string?  If not, go to (10).
-  __ bind(&not_seq_nor_cons);
-  // Compare flags are still set from (3).
-  __ j(greater, &not_long_external, Label::kNear);  // Go to (10).
-
-  // (7) External string.  Short external strings have been ruled out.
-  __ bind(&external_string);
-  __ movp(rbx, FieldOperand(rdi, HeapObject::kMapOffset));
-  __ movzxbl(rbx, FieldOperand(rbx, Map::kInstanceTypeOffset));
-  if (FLAG_debug_code) {
-    // Assert that we do not have a cons or slice (indirect strings) here.
-    // Sequential strings have already been ruled out.
-    __ testb(rbx, Immediate(kIsIndirectStringMask));
-    __ Assert(zero, kExternalStringExpectedButNotFound);
-  }
-  __ movp(rdi, FieldOperand(rdi, ExternalString::kResourceDataOffset));
-  // Move the pointer so that offset-wise, it looks like a sequential string.
-  STATIC_ASSERT(SeqTwoByteString::kHeaderSize == SeqOneByteString::kHeaderSize);
-  __ subp(rdi, Immediate(SeqTwoByteString::kHeaderSize - kHeapObjectTag));
-  STATIC_ASSERT(kTwoByteStringTag == 0);
-  // (8) Is the external string one byte?  If yes, go to (5).
-  __ testb(rbx, Immediate(kStringEncodingMask));
-  __ j(not_zero, &seq_one_byte_string);  // Go to (5).
-
-  // rdi: subject string (flat two-byte)
-  // rax: RegExp data (FixedArray)
-  // (9) Two byte sequential.  Load regexp code for two byte.  Go to (E).
-  __ bind(&seq_two_byte_string);
-  __ movp(r11, FieldOperand(rax, JSRegExp::kDataUC16CodeOffset));
-  __ Set(rcx, 0);  // Type is two byte.
-  __ jmp(&check_code);  // Go to (E).
-
-  // (10) Not a string or a short external string?  If yes, bail out to runtime.
-  __ bind(&not_long_external);
-  // Catch non-string subject or short external string.
-  STATIC_ASSERT(kNotStringTag != 0 && kShortExternalStringTag !=0);
-  __ testb(rbx, Immediate(kIsNotStringMask | kShortExternalStringMask));
-  __ j(not_zero, &runtime);
-
-  // (11) Sliced or thin string.  Replace subject with parent. Go to (1).
-  Label thin_string;
-  __ cmpl(rbx, Immediate(kThinStringTag));
-  __ j(equal, &thin_string, Label::kNear);
-  // Load offset into r14 and replace subject string with parent.
-  __ SmiToInteger32(r14, FieldOperand(rdi, SlicedString::kOffsetOffset));
-  __ movp(rdi, FieldOperand(rdi, SlicedString::kParentOffset));
-  __ jmp(&check_underlying);
-
-  __ bind(&thin_string);
-  __ movp(rdi, FieldOperand(rdi, ThinString::kActualOffset));
-  __ jmp(&check_underlying);
+  // TODO(jgruber): Don't tag return value once this is supported by stubs.
+  __ Integer32ToSmi(rax, rax);
+  __ ret(0 * kPointerSize);
 #endif  // V8_INTERPRETED_REGEXP
 }
 
 
 static int NegativeComparisonResult(Condition cc) {
   DCHECK(cc != equal);
   DCHECK((cc == less) || (cc == less_equal)
       || (cc == greater) || (cc == greater_equal));
   return (cc == greater || cc == greater_equal) ? LESS : GREATER;
 }
@@ skipping 2537 matching lines @@
                            kStackUnwindSpace, nullptr, return_value_operand,
                            NULL);
 }
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64