diff --git a/include/simdjson/portability.h b/include/simdjson/portability.h
index f2f22bc9d..65ad545ee 100644
--- a/include/simdjson/portability.h
+++ b/include/simdjson/portability.h
@@ -27,16 +27,20 @@
 #define TARGET_REGION(T)                                                       \
   _Pragma("GCC push_options") _Pragma(STRINGIFY(GCC target(T)))
 #define UNTARGET_REGION _Pragma("GCC pop_options")
-#else
+#endif // clang then gcc
+
+#endif  // x86
+
+// Default target region macros don't do anything.
+#ifndef TARGET_REGION
 #define TARGET_REGION(T)
 #define UNTARGET_REGION
-#endif // clang then gcc
+#endif
 
 // under GCC and CLANG, we use these two macros
 #define TARGET_HASWELL TARGET_REGION("avx2,bmi,pclmul")
 #define TARGET_WESTMERE TARGET_REGION("sse4.2,pclmul")
-
-#endif // x86
+#define TARGET_ARM64
 
 #ifdef _MSC_VER
 #include <intrin.h>
diff --git a/include/simdjson/stage1_find_marks_common.h b/include/simdjson/stage1_find_marks_common.h
index b5840cb26..73c05af3c 100644
--- a/include/simdjson/stage1_find_marks_common.h
+++ b/include/simdjson/stage1_find_marks_common.h
@@ -4,6 +4,10 @@
 // "simdjson/stage1_find_marks.h" (this simplifies amalgation)
 
 #ifdef TARGETED_ARCHITECTURE
+#ifdef TARGETED_REGION
+
+TARGETED_REGION
+namespace simdjson {
 
 // return a bitvector indicating where we have characters that end an odd-length
 // sequence of backslashes (and thus change the behavior of the next character
@@ -226,4 +230,12 @@ int find_structural_bits<TARGETED_ARCHITECTURE>(const uint8_t *buf, size_t len,
   return check_utf8_errors<TARGETED_ARCHITECTURE>(utf8_state);
 }
 
+} // namespace simdjson
+UNTARGET_REGION
+
+#else
+#error TARGETED_REGION must be specified before including.
+#endif // TARGETED_REGION
+#else
+#error TARGETED_ARCHITECTURE must be specified before including.
 #endif // TARGETED_ARCHITECTURE
diff --git a/include/simdjson/stage2_build_tape_common.h b/include/simdjson/stage2_build_tape_common.h
index 1413491cb..f54206060 100644
--- a/include/simdjson/stage2_build_tape_common.h
+++ b/include/simdjson/stage2_build_tape_common.h
@@ -4,6 +4,11 @@
 // "simdjson/stage2_build_tape.h" (this simplifies amalgation)
 
 #ifdef TARGETED_ARCHITECTURE
+#ifdef TARGETED_REGION
+
+TARGETED_REGION
+namespace simdjson {
+
 // this macro reads the next structural character, updating idx, i and c.
 #define UPDATE_CHAR()                                                          \
   {                                                                            \
@@ -522,4 +527,12 @@ fail:
   return pj.error_code;
 }
 
+} // namespace simdjson
+UNTARGET_REGION
+
+#else
+#error TARGETED_REGION must be specified before including.
+#endif // TARGETED_REGION
+#else
+#error TARGETED_ARCHITECTURE must be specified before including.
 #endif // TARGETED_ARCHITECTURE
diff --git a/include/simdjson/stringparsing_arm64.h b/include/simdjson/stringparsing_arm64.h
index 5053921c1..3036ff292 100644
--- a/include/simdjson/stringparsing_arm64.h
+++ b/include/simdjson/stringparsing_arm64.h
@@ -41,10 +41,13 @@ find_bs_bits_and_quote_bits<Architecture::ARM64>(const uint8_t *src,
   };
 }
 
+} // namespace simdjson
+
 #define TARGETED_ARCHITECTURE Architecture::ARM64
+#define TARGETED_REGION TARGET_ARM64
 #include "simdjson/stringparsing_common.h"
 #undef TARGETED_ARCHITECTURE
+#undef TARGETED_REGION
 
-} // namespace simdjson
-#endif
+#endif // IS_ARM64
 #endif
diff --git a/include/simdjson/stringparsing_common.h b/include/simdjson/stringparsing_common.h
index 2d8914d56..fe497b8fe 100644
--- a/include/simdjson/stringparsing_common.h
+++ b/include/simdjson/stringparsing_common.h
@@ -4,6 +4,11 @@
 // "simdjson/stringparsing.h" (this simplifies amalgation)
 
 #ifdef TARGETED_ARCHITECTURE
+#ifdef TARGETED_REGION
+
+TARGETED_REGION
+namespace simdjson {
+
 template <>
 WARN_UNUSED ALLOW_SAME_PAGE_BUFFER_OVERRUN_QUALIFIER LENIENT_MEM_SANITIZER
     really_inline bool
@@ -88,4 +93,12 @@ WARN_UNUSED ALLOW_SAME_PAGE_BUFFER_OVERRUN_QUALIFIER LENIENT_MEM_SANITIZER
   return true;
 }
 
+} // namespace simdjson
+UNTARGET_REGION
+
+#else
+#error TARGETED_REGION must be specified before including.
+#endif // TARGETED_REGION
+#else
+#error TARGETED_ARCHITECTURE must be specified before including.
 #endif // TARGETED_ARCHITECTURE
diff --git a/include/simdjson/stringparsing_haswell.h b/include/simdjson/stringparsing_haswell.h
index 3f28a2c73..d51b9f551 100644
--- a/include/simdjson/stringparsing_haswell.h
+++ b/include/simdjson/stringparsing_haswell.h
@@ -24,13 +24,15 @@ find_bs_bits_and_quote_bits<Architecture::HASWELL>(const uint8_t *src,
       static_cast<uint32_t>(_mm256_movemask_epi8(quote_mask)) // quote_bits
   };
 }
-
-#define TARGETED_ARCHITECTURE Architecture::HASWELL
-#include "simdjson/stringparsing_common.h"
-#undef TARGETED_ARCHITECTURE
-
 } // namespace simdjson
 UNTARGET_REGION
-#endif
+
+#define TARGETED_ARCHITECTURE Architecture::HASWELL
+#define TARGETED_REGION TARGET_HASWELL
+#include "simdjson/stringparsing_common.h"
+#undef TARGETED_ARCHITECTURE
+#undef TARGETED_REGION
+
+#endif // IS_X86_64
 
 #endif
diff --git a/include/simdjson/stringparsing_westmere.h b/include/simdjson/stringparsing_westmere.h
index 1481f1bf0..5dca7bb48 100644
--- a/include/simdjson/stringparsing_westmere.h
+++ b/include/simdjson/stringparsing_westmere.h
@@ -23,13 +23,15 @@ find_bs_bits_and_quote_bits<Architecture::WESTMERE>(const uint8_t *src,
       static_cast<uint32_t>(_mm_movemask_epi8(quote_mask)) // quote_bits
   };
 }
-
-#define TARGETED_ARCHITECTURE Architecture::WESTMERE
-#include "simdjson/stringparsing_common.h"
-#undef TARGETED_ARCHITECTURE
-
 } // namespace simdjson
 UNTARGET_REGION
-#endif
+
+#define TARGETED_ARCHITECTURE Architecture::WESTMERE
+#define TARGETED_REGION TARGET_WESTMERE
+#include "simdjson/stringparsing_common.h"
+#undef TARGETED_ARCHITECTURE
+#undef TARGETED_REGION
+
+#endif // IS_X86_64
 
 #endif
diff --git a/src/stage1_find_marks.cpp b/src/stage1_find_marks.cpp
index ab1c5eff4..563d764bc 100644
--- a/src/stage1_find_marks.cpp
+++ b/src/stage1_find_marks.cpp
@@ -2,32 +2,32 @@
 #include "simdjson/portability.h"
 
 #ifdef IS_X86_64
+
 #include "simdjson/stage1_find_marks_haswell.h"
 #include "simdjson/stage1_find_marks_westmere.h"
 
-TARGET_HASWELL
-namespace simdjson {
 #define TARGETED_ARCHITECTURE Architecture::HASWELL
+#define TARGETED_REGION TARGET_HASWELL
 #include "simdjson/stage1_find_marks_common.h"
 #undef TARGETED_ARCHITECTURE
-} // namespace simdjson
-UNTARGET_REGION
+#undef TARGETED_REGION
 
-TARGET_WESTMERE
-namespace simdjson {
 #define TARGETED_ARCHITECTURE Architecture::WESTMERE
+#define TARGETED_REGION TARGET_WESTMERE
 #include "simdjson/stage1_find_marks_common.h"
 #undef TARGETED_ARCHITECTURE
-} // namespace simdjson
-UNTARGET_REGION
+#undef TARGETED_REGION
 
 #endif // IS_X86_64
 
 #ifdef IS_ARM64
+
 #include "simdjson/stage1_find_marks_arm64.h"
-namespace simdjson {
+
 #define TARGETED_ARCHITECTURE Architecture::ARM64
+#define TARGETED_REGION TARGET_ARM64
 #include "simdjson/stage1_find_marks_common.h"
 #undef TARGETED_ARCHITECTURE
-} // namespace simdjson
+#undef TARGETED_REGION
+
 #endif // IS_ARM64
diff --git a/src/stage2_build_tape.cpp b/src/stage2_build_tape.cpp
index ae831bc7c..2286b0e5d 100644
--- a/src/stage2_build_tape.cpp
+++ b/src/stage2_build_tape.cpp
@@ -1,27 +1,23 @@
 #include "simdjson/stage2_build_tape.h"
 
 #ifdef IS_X86_64
-TARGET_HASWELL
-namespace simdjson {
 #define TARGETED_ARCHITECTURE Architecture::HASWELL
+#define TARGETED_REGION TARGET_HASWELL
 #include "simdjson/stage2_build_tape_common.h"
 #undef TARGETED_ARCHITECTURE
-} // namespace simdjson
-UNTARGET_REGION
+#undef TARGETED_REGION
 
-TARGET_WESTMERE
-namespace simdjson {
 #define TARGETED_ARCHITECTURE Architecture::WESTMERE
+#define TARGETED_REGION TARGET_WESTMERE
 #include "simdjson/stage2_build_tape_common.h"
 #undef TARGETED_ARCHITECTURE
-} // namespace simdjson
-UNTARGET_REGION
+#undef TARGETED_REGION
 #endif // IS_X86_64
 
 #ifdef IS_ARM64
-namespace simdjson {
 #define TARGETED_ARCHITECTURE Architecture::ARM64
+#define TARGETED_REGION TARGET_ARM64
 #include "simdjson/stage2_build_tape_common.h"
 #undef TARGETED_ARCHITECTURE
-} // namespace simdjson
-#endif
+#undef TARGETED_REGION
+#endif // IS_ARM64