[libc++] Remove a few incorrect _LIBCPP_EXPORTED_FROM_ABI annotations (llvm#132602)

This has two benefits:
- It is less likely that the macro will be copy-pasted around when
unnecessary
- We can drop `_LIBCPP_HIDE_FROM_ABI` from any member functions once we
are able to make `_LIBCPP_HIDE_FROM_ABI` the default within libc++

Author: philnik777

libcxx/docs/DesignDocs/VisibilityMacros.rst

@@ -31,7 +31,9 @@ Visibility Macros
   Mark a symbol as being part of our ABI. This includes functions that are part
   of the libc++ library, type information and other symbols. On Windows,
   this macro applies `dllimport`/`dllexport` to the symbol, and on other
-  platforms it gives the symbol default visibility.
+  platforms it gives the symbol default visibility. This macro should never be
+  used on class templates. On classes it should only be used if the vtable
+  lives in the built library.
 
 **_LIBCPP_OVERRIDABLE_FUNC_VIS**
   Mark a symbol as being exported by the libc++ library, but allow it to be

libcxx/include/__charconv/from_chars_result.h

@@ -21,7 +21,7 @@ _LIBCPP_BEGIN_NAMESPACE_STD
 
 #if _LIBCPP_STD_VER >= 17
 
-struct _LIBCPP_EXPORTED_FROM_ABI from_chars_result {
+struct from_chars_result {
   const char* ptr;
   errc ec;
 #  if _LIBCPP_STD_VER >= 20

libcxx/include/__charconv/to_chars_result.h

@@ -21,7 +21,7 @@ _LIBCPP_BEGIN_NAMESPACE_STD
 
 #if _LIBCPP_STD_VER >= 17
 
-struct _LIBCPP_EXPORTED_FROM_ABI to_chars_result {
+struct to_chars_result {
   char* ptr;
   errc ec;
 #  if _LIBCPP_STD_VER >= 20

libcxx/include/__filesystem/file_status.h

@@ -22,7 +22,7 @@
 
 _LIBCPP_BEGIN_NAMESPACE_FILESYSTEM
 
-class _LIBCPP_EXPORTED_FROM_ABI file_status {
+class file_status {
 public:
   // constructors
   _LIBCPP_HIDE_FROM_ABI file_status() noexcept : file_status(file_type::none) {}

libcxx/include/__filesystem/path.h

@@ -861,7 +861,7 @@ class _LIBCPP_EXPORTED_FROM_ABI path {
   }
 
   // iterators
-  class _LIBCPP_EXPORTED_FROM_ABI iterator;
+  class iterator;
   typedef iterator const_iterator;
 
   iterator begin() const;

libcxx/include/__filesystem/space_info.h

@@ -21,7 +21,7 @@
 
 _LIBCPP_BEGIN_NAMESPACE_FILESYSTEM
 
-struct _LIBCPP_EXPORTED_FROM_ABI space_info {
+struct space_info {
   uintmax_t capacity;
   uintmax_t free;
   uintmax_t available;

libcxx/include/__format/formatter_output.h

@@ -45,7 +45,7 @@ _LIBCPP_BEGIN_NAMESPACE_STD
 
 namespace __formatter {
 
-struct _LIBCPP_EXPORTED_FROM_ABI __padding_size_result {
+struct __padding_size_result {
   size_t __before_;
   size_t __after_;
 };

libcxx/include/__memory_resource/pool_options.h

@@ -24,7 +24,7 @@ namespace pmr {
 
 // [mem.res.pool.options]
 
-struct _LIBCPP_EXPORTED_FROM_ABI pool_options {
+struct pool_options {
   size_t max_blocks_per_chunk        = 0;
   size_t largest_required_pool_block = 0;
 };

libcxx/include/__mutex/tag_types.h

@@ -17,15 +17,15 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-struct _LIBCPP_EXPORTED_FROM_ABI defer_lock_t {
+struct defer_lock_t {
   explicit defer_lock_t() = default;
 };
 
-struct _LIBCPP_EXPORTED_FROM_ABI try_to_lock_t {
+struct try_to_lock_t {
   explicit try_to_lock_t() = default;
 };
 
-struct _LIBCPP_EXPORTED_FROM_ABI adopt_lock_t {
+struct adopt_lock_t {
   explicit adopt_lock_t() = default;
 };
 

libcxx/include/__new/nothrow_t.h

@@ -19,7 +19,7 @@
 #  include <new.h>
 #else
 _LIBCPP_BEGIN_UNVERSIONED_NAMESPACE_STD
-struct _LIBCPP_EXPORTED_FROM_ABI nothrow_t {
+struct nothrow_t {
   explicit nothrow_t() = default;
 };
 extern _LIBCPP_EXPORTED_FROM_ABI const nothrow_t nothrow;