Add mips64 port.

src/assembler.cc

Index: src/assembler.cc
diff --git a/src/assembler.cc b/src/assembler.cc
index 4faf6430bfb00daceb1d99e3fbb9d69e789571da..2e5e82854340296b9c0cbeeaa57a414c0825419c 100644
--- a/src/assembler.cc
+++ b/src/assembler.cc
@@ -66,6 +66,8 @@
 #include "src/arm/assembler-arm-inl.h"  // NOLINT
 #elif V8_TARGET_ARCH_MIPS
 #include "src/mips/assembler-mips-inl.h"  // NOLINT
+#elif V8_TARGET_ARCH_MIPS64
+#include "src/mips64/assembler-mips64-inl.h"  // NOLINT
 #elif V8_TARGET_ARCH_X87
 #include "src/x87/assembler-x87-inl.h"  // NOLINT
 #else
@@ -84,6 +86,8 @@
 #include "src/arm/regexp-macro-assembler-arm.h"  // NOLINT
 #elif V8_TARGET_ARCH_MIPS
 #include "src/mips/regexp-macro-assembler-mips.h"  // NOLINT
+#elif V8_TARGET_ARCH_MIPS64
+#include "src/mips64/regexp-macro-assembler-mips64.h"  // NOLINT
 #elif V8_TARGET_ARCH_X87
 #include "src/x87/regexp-macro-assembler-x87.h"  // NOLINT
 #else  // Unknown architecture.
@@ -1340,6 +1344,8 @@ ExternalReference ExternalReference::re_check_stack_guard_state(
   function = FUNCTION_ADDR(RegExpMacroAssemblerARM::CheckStackGuardState);
 #elif V8_TARGET_ARCH_MIPS
   function = FUNCTION_ADDR(RegExpMacroAssemblerMIPS::CheckStackGuardState);
+#elif V8_TARGET_ARCH_MIPS64
+  function = FUNCTION_ADDR(RegExpMacroAssemblerMIPS::CheckStackGuardState);
 #elif V8_TARGET_ARCH_X87
   function = FUNCTION_ADDR(RegExpMacroAssemblerX87::CheckStackGuardState);
 #else