Encode JSON_VIEW_NO_SIMD and JSON_VIEW_USE_SSSE3 in the ABI namespace

Both macros select between definitions of the same inline functions, so
translation units that disagree on them violated the ODR. Like the other
ABI-affecting macros, they now add a tag to the inline namespace (_vns and
_vssse3), and the docs replace the "Define consistently" warning with the
usual ABI compatibility note. From gregmarr's review of #5628.

nlohmann_json.natvis covers twice as many tags now, so it lists four times
as many namespaces (14.7 MB instead of 3.4 MB).

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

docs/mkdocs/docs/api/macros/json_view_no_simd.md

@@ -14,10 +14,12 @@ The same input is accepted or rejected either way, with the same values, and err
 the speed differs. The macro exists for platforms whose compilers lack the intrinsics headers, and to test the portable
 code.
 
-!!! warning "Define consistently"
+!!! note "ABI compatibility"
 
-    The macro selects between two definitions of the same inline functions. It must therefore be defined identically for
+    The macro selects between two definitions of the same inline functions. Whether it is defined is encoded in the
-    **every** translation unit that includes `<nlohmann/json_view.hpp>`; prefer a compile definition on the target.
+    [namespace](../../features/namespace.md) (tag `_vns`), resulting in distinct symbol names. Translation units
+    compiled with and without it can therefore be linked into the same program without One Definition Rule (ODR)
+    violations, but they cannot exchange instances of library types.
 
 ## Default definition
 

docs/mkdocs/docs/api/macros/json_view_use_ssse3.md

@@ -17,12 +17,12 @@ Define the macro only together with a compiler option that enables SSSE3 (e.g. `
 has it), and only for programs that run on such CPUs. It saves the check of the CPU, which costs little. The same
 input is accepted or rejected either way; only the speed of non-ASCII text differs.
 
-!!! warning "Define consistently"
+!!! note "ABI compatibility"
 
-    The macro selects between two definitions of the same inline functions. It must therefore be defined identically,
+    The macro selects between two definitions of the same inline functions. Whether it is defined is encoded in the
-    with the same compiler options, for **every** translation unit that includes `<nlohmann/json_view.hpp>`; mixing
+    [namespace](../../features/namespace.md) (tag `_vssse3`, on every architecture), resulting in distinct symbol
-    translation units that define it with ones that do not is an ODR violation. Prefer a compile definition on the
+    names. Translation units compiled with and without it can therefore be linked into the same program without One
-    target.
+    Definition Rule (ODR) violations, but they cannot exchange instances of library types.
 
 ## Default definition
 

docs/mkdocs/docs/api/macros/nlohmann_json_namespace.md

@@ -39,5 +39,6 @@ the library.
 ## Version history
 
 - Added in version 3.11.0. Changed inline namespace name in version 3.11.2. Added the ABI tag `_dp` in
-  version 3.12.0, and the ABI tags `_bics`, `_psp`, `_snul`, `_sbu8`, and `_ekmo` in version 3.13.0; see
+  version 3.12.0, and the ABI tags `_bics`, `_psp`, `_snul`, `_sbu8`, `_ekmo`, `_vns`, and `_vssse3` in version
+  3.13.0; see
   [`nlohmann` Namespace](../../features/namespace.md#structure).

docs/mkdocs/docs/features/namespace.md

@@ -23,6 +23,8 @@ The complete default namespace name is derived as follows:
     - [`JSON_STRICT_BINARY_UTF8`](../api/macros/json_strict_binary_utf8.md) defined non-zero appends `_sbu8`.
     - [`JSON_USE_OBJECTS_FOR_ENUM_KEYED_MAPS`](../api/macros/json_use_objects_for_enum_keyed_maps.md) defined non-zero
       appends `_ekmo`.
+    - [`JSON_VIEW_NO_SIMD`](../api/macros/json_view_no_simd.md) defined appends `_vns`.
+    - [`JSON_VIEW_USE_SSSE3`](../api/macros/json_view_use_ssse3.md) defined appends `_vssse3`.
 - The inline namespace ends with the suffix `_v` followed by the 3 components of the version number separated by
   underscores. To omit the version component, see [Disabling the version component](#disabling-the-version-component)
   below.
@@ -105,5 +107,7 @@ follows:
 - Added ABI tags `_bics` ([`JSON_BRACE_INIT_COPY_SEMANTICS`](../api/macros/json_brace_init_copy_semantics.md)), `_psp`
   ([`JSON_PRECISE_STREAM_POSITION`](../api/macros/json_precise_stream_position.md)), `_snul`
   ([`JSON_STRICT_NUL_HANDLING`](../api/macros/json_strict_nul_handling.md)), `_sbu8`
-  ([`JSON_STRICT_BINARY_UTF8`](../api/macros/json_strict_binary_utf8.md)), and `_ekmo`
+  ([`JSON_STRICT_BINARY_UTF8`](../api/macros/json_strict_binary_utf8.md)), `_ekmo`
-  ([`JSON_USE_OBJECTS_FOR_ENUM_KEYED_MAPS`](../api/macros/json_use_objects_for_enum_keyed_maps.md)) in version 3.13.0.
+  ([`JSON_USE_OBJECTS_FOR_ENUM_KEYED_MAPS`](../api/macros/json_use_objects_for_enum_keyed_maps.md)), `_vns`
+  ([`JSON_VIEW_NO_SIMD`](../api/macros/json_view_no_simd.md)), and `_vssse3`
+  ([`JSON_VIEW_USE_SSSE3`](../api/macros/json_view_use_ssse3.md)) in version 3.13.0.

include/nlohmann/detail/abi_macros.hpp

@@ -102,14 +102,26 @@
     #define NLOHMANN_JSON_ABI_TAG_OBJECTS_FOR_ENUM_KEYED_MAPS
 #endif
 
+#ifdef JSON_VIEW_NO_SIMD
+    #define NLOHMANN_JSON_ABI_TAG_VIEW_NO_SIMD _vns
+#else
+    #define NLOHMANN_JSON_ABI_TAG_VIEW_NO_SIMD
+#endif
+
+#ifdef JSON_VIEW_USE_SSSE3
+    #define NLOHMANN_JSON_ABI_TAG_VIEW_USE_SSSE3 _vssse3
+#else
+    #define NLOHMANN_JSON_ABI_TAG_VIEW_USE_SSSE3
+#endif
+
 #ifndef NLOHMANN_JSON_NAMESPACE_NO_VERSION
     #define NLOHMANN_JSON_NAMESPACE_NO_VERSION 0
 #endif
 
 // Construct the namespace ABI tags component
-#define NLOHMANN_JSON_ABI_TAGS_CONCAT_EX(a, b, c, d, e, f, g, h) json_abi ## a ## b ## c ## d ## e ## f ## g ## h
+#define NLOHMANN_JSON_ABI_TAGS_CONCAT_EX(a, b, c, d, e, f, g, h, i, j) json_abi ## a ## b ## c ## d ## e ## f ## g ## h ## i ## j
-#define NLOHMANN_JSON_ABI_TAGS_CONCAT(a, b, c, d, e, f, g, h) \
+#define NLOHMANN_JSON_ABI_TAGS_CONCAT(a, b, c, d, e, f, g, h, i, j) \
-    NLOHMANN_JSON_ABI_TAGS_CONCAT_EX(a, b, c, d, e, f, g, h)
+    NLOHMANN_JSON_ABI_TAGS_CONCAT_EX(a, b, c, d, e, f, g, h, i, j)
 
 #define NLOHMANN_JSON_ABI_TAGS                                       \
     NLOHMANN_JSON_ABI_TAGS_CONCAT(                                   \
@@ -120,7 +132,9 @@
             NLOHMANN_JSON_ABI_TAG_PRECISE_STREAM_POSITION,           \
             NLOHMANN_JSON_ABI_TAG_STRICT_NUL_HANDLING,               \
             NLOHMANN_JSON_ABI_TAG_STRICT_BINARY_UTF8,                \
-            NLOHMANN_JSON_ABI_TAG_OBJECTS_FOR_ENUM_KEYED_MAPS)
+            NLOHMANN_JSON_ABI_TAG_OBJECTS_FOR_ENUM_KEYED_MAPS,       \
+            NLOHMANN_JSON_ABI_TAG_VIEW_NO_SIMD,                      \
+            NLOHMANN_JSON_ABI_TAG_VIEW_USE_SSSE3)
 
 // Construct the namespace version component
 #define NLOHMANN_JSON_NAMESPACE_VERSION_CONCAT_EX(major, minor, patch) \

tests/abi/config/CMakeLists.txt

@@ -21,7 +21,9 @@ foreach(test default noversion)
     target_compile_definitions(abi_config_${test}_all_tags PRIVATE
         JSON_DIAGNOSTICS=1
         JSON_DIAGNOSTIC_POSITIONS=1
-        JSON_USE_LEGACY_DISCARDED_VALUE_COMPARISON=1)
+        JSON_USE_LEGACY_DISCARDED_VALUE_COMPARISON=1
+        JSON_VIEW_NO_SIMD
+        JSON_VIEW_USE_SSSE3)
     target_link_libraries(abi_config_${test}_all_tags PRIVATE abi_compat_main)
     add_test(
         NAME test-abi_config_${test}_all_tags

tests/abi/config/default.cpp

@@ -52,6 +52,14 @@ TEST_CASE("default namespace")
         expected += "_ekmo";
 #endif
 
+#ifdef JSON_VIEW_NO_SIMD
+        expected += "_vns";
+#endif
+
+#ifdef JSON_VIEW_USE_SSSE3
+        expected += "_vssse3";
+#endif
+
         expected += "_v" STRINGIZE(NLOHMANN_JSON_VERSION_MAJOR);
         expected += "_" STRINGIZE(NLOHMANN_JSON_VERSION_MINOR);
         expected += "_" STRINGIZE(NLOHMANN_JSON_VERSION_PATCH) "::basic_json";

tests/abi/config/noversion.cpp

@@ -53,6 +53,14 @@ TEST_CASE("default namespace without version component")
         expected += "_ekmo";
 #endif
 
+#ifdef JSON_VIEW_NO_SIMD
+        expected += "_vns";
+#endif
+
+#ifdef JSON_VIEW_USE_SSSE3
+        expected += "_vssse3";
+#endif
+
         expected += "::basic_json";
 
         // fallback for Clang