Add asserts to ensure that we:

src/x64/regexp-macro-assembler-x64.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 413 matching lines @@
     __ lea(rax, Operand(rsi, rdi, times_1, 0));
     // Compute and set byte_offset1 (start of capture).
     __ lea(rdi, Operand(rsi, rdx, times_1, 0));
     // Set byte_offset2.
     __ movq(rsi, rax);
     // Set byte_length.
     __ movq(rdx, rbx);
     // Isolate.
     __ LoadAddress(rcx, ExternalReference::isolate_address());
 #endif
-    ExternalReference compare =
-        ExternalReference::re_case_insensitive_compare_uc16(masm_.isolate());
-    __ CallCFunction(compare, num_arguments);
+
+    { // 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(masm_.isolate());
+      __ CallCFunction(compare, num_arguments);
+    }
 
     // Restore original values before reacting on result value.
     __ Move(code_object_pointer(), masm_.CodeObject());
     __ pop(backtrack_stackpointer());
 #ifndef _WIN64
     __ pop(rdi);
     __ pop(rsi);
 #endif
 
     // Check if function returned non-zero for success or zero for failure.
@@ skipping 252 matching lines @@
   __ Set(rax, 0);
   __ jmp(&exit_label_);
 }
 
 
 Handle<HeapObject> RegExpMacroAssemblerX64::GetCode(Handle<String> source) {
   // Finalize code - write the entry point code now we know how many
   // registers we need.
   // Entry code:
   __ bind(&entry_label_);
-  // Start new stack frame.
+
+  // 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.
   __ push(rbp);
   __ movq(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);
@@ skipping 681 matching lines @@
   }
 }
 
 #undef __
 
 #endif  // V8_INTERPRETED_REGEXP
 
 }}  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64