pw_polyfill: Remove implicit polyfills for C++14

Remove implicit <cstddef>, <iterator>, and <type_traits> polyfills. The polyfill headers can be depended on explicitly if needed. Bug: 602 Change-Id: I6f45a2cf7d275ac07d6cf7f0fd7c55cce8ac0b63 Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/96443 Reviewed-by: Armando Montanez <amontanez@google.com> Commit-Queue: Auto-Submit <auto-submit@pigweed.google.com.iam.gserviceaccount.com> Pigweed-Auto-Submit: Wyatt Hepler <hepler@google.com>
google · Jun 2, 2022 · 24d03e5 · 24d03e5
1 parent 75a269c
commit 24d03e5
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Showing 4 changed files with 26 additions and 28 deletions.
diff --git a/pw_polyfill/BUILD.bazel b/pw_polyfill/BUILD.bazel
@@ -58,10 +58,7 @@ pw_cc_library(
     name = "overrides",
     deps = [
         ":bit",
-        ":cstddef",
-        ":iterator",
         ":span",
-        ":type_traits",
     ],
 )
 

diff --git a/pw_polyfill/BUILD.gn b/pw_polyfill/BUILD.gn
@@ -43,10 +43,7 @@ config("overrides_config") {
 group("overrides") {
   public_deps = [
     ":bit",
-    ":cstddef",
-    ":iterator",
     ":span",
-    ":type_traits",
   ]
 }
 
@@ -123,7 +120,12 @@ pw_test_group("tests") {
 }
 
 pw_test("test") {
-  deps = [ ":pw_polyfill" ]
+  deps = [
+    ":cstddef",
+    ":iterator",
+    ":pw_polyfill",
+    ":type_traits",
+  ]
   sources = [ "test.cc" ]
 }
 

diff --git a/pw_polyfill/CMakeLists.txt b/pw_polyfill/CMakeLists.txt
@@ -30,10 +30,7 @@ endif()
 pw_add_module_library(pw_polyfill.overrides
   PUBLIC_DEPS
     pw_polyfill.bit
-    pw_polyfill.cstddef
-    pw_polyfill.iterator
     pw_polyfill.span
-    pw_polyfill.type_traits
 )
 if(Zephyr_FOUND AND CONFIG_PIGWEED_POLYFILL_OVERRIDES)
   zephyr_link_libraries(pw_polyfill.overrides)

diff --git a/pw_polyfill/docs.rst b/pw_polyfill/docs.rst
@@ -23,29 +23,31 @@ provided by the standard header, so ``pw_polyfill`` is safe to use when
 compiling with any standard C++14 or newer.
 
 The wrapper headers are in ``public_overrides``. These are provided through the
-``"$dir_pw_polyfill"`` libraries, which the GN build adds as a
-dependency for all targets:
+following libraries:
 
-* ``$dir_pw_polyfill:bit``
-* ``$dir_pw_polyfill:cstddef``
-* ``$dir_pw_polyfill:iterator``
-* ``$dir_pw_polyfill:span``
-* ``$dir_pw_polyfill:type_traits``
+* ``pw_polyfill:bit``
+* ``pw_polyfill:cstddef``
+* ``pw_polyfill:iterator``
+* ``pw_polyfill:span``
+* ``pw_polyfill:type_traits``
 
-To apply overrides in Bazel or CMake, depend on the targets you need such as
-``//pw_polyfill:span`` or ``pw_polyfill.span`` as an example.
+The GN build automatically adds dependencies on the ``<bit>`` and ``<span>``
+headers. To apply other overrides, add dependencies as needed. In Bazel or
+CMake, overrides are not applied automatically, so depend on the targets you
+need such as ``//pw_polyfill:span`` or ``pw_polyfill.span``.
 
 Backported features
 ===================
-==================  ================================  ===============================  ========================================
-Header              Feature                           Level of support                 Feature test macro
-==================  ================================  ===============================  ========================================
-<bit>               std::endian                       full                             __cpp_lib_endian
-<cstdlib>           std::byte                         full                             __cpp_lib_byte
-<iterator>          std::data, std::size              full                             __cpp_lib_nonmember_container_access
-<type_traits>       std::bool_constant                full                             __cpp_lib_bool_constant
-<type_traits>       std::negation, etc.               full                             __cpp_lib_logical_traits
-==================  ================================  ===============================  ========================================
+==================  ================================  ================  ======================================== =============
+Header              Feature                           Level of support  Feature test macro                       Implicit dep?
+==================  ================================  ================  ======================================== =============
+<bit>               std::endian                       full              __cpp_lib_endian                         GN
+<cstdlib>           std::byte                         full              __cpp_lib_byte                           ❌
+<iterator>          std::data, std::size              full              __cpp_lib_nonmember_container_access     ❌
+<span>              std::span                         no std::ranges    __cpp_lib_span                           GN
+<type_traits>       std::bool_constant                full              __cpp_lib_bool_constant                  ❌
+<type_traits>       std::negation, etc.               full              __cpp_lib_logical_traits                 ❌
+==================  ================================  ================  ======================================== =============
 
 ----------------------------------------------------
 Adapt code to compile with different versions of C++