[libcxx-commits] [libcxx] b0829c5 - libcxx: fixups for __BIONIC__ (#219591)

[via libcxx-commits]

Author: Nick Desaulniers
Date: 2026-09-01T09:46:04-07:00
New Revision: b0829c5a09a9cc480718df21d90c454be5dddb88

URL: https://github.com/llvm/llvm-project/commit/b0829c5a09a9cc480718df21d90c454be5dddb88
DIFF: https://github.com/llvm/llvm-project/commit/b0829c5a09a9cc480718df21d90c454be5dddb88.diff

LOG: libcxx: fixups for __BIONIC__ (#219591)

A few header guards seem to check various libc's, but not Android's libc
(Bionic).

Bionic supports:
- arc4random
- copy_file_range
- getcwd() extension

Link:
https://android-review.git.corp.google.com/c/platform/bionic/+/41445
Link:
https://android.googlesource.com/platform/bionic/+/refs/heads/main/libc/SYSCALLS.TXT
Link:
https://android.googlesource.com/platform/bionic/+/refs/heads/main/libc/upstream-openbsd/lib/libc/crypt/arc4random.c

Added: 
    

Modified: 
    libcxx/include/__config
    libcxx/include/__cxx03/__config
    libcxx/src/filesystem/operations.cpp

Removed: 
    


################################################################################
diff  --git a/libcxx/include/__config b/libcxx/include/__config
index fddcae5bc663b..e98aea7be8531 100644
--- a/libcxx/include/__config
+++ b/libcxx/include/__config
@@ -83,7 +83,7 @@
 //      When this option is used, the token passed to `std::random_device`'s
 //      constructor *must* be "/dev/urandom" -- anything else is an error.
 #  if defined(__APPLE__) || defined(__FreeBSD__) || defined(__NetBSD__) || defined(__OpenBSD__) ||                     \
-      defined(__DragonFly__)
+      defined(__DragonFly__) || defined(__BIONIC__)
 #    define _LIBCPP_USING_ARC4_RANDOM
 #  elif defined(__wasi__) || defined(__EMSCRIPTEN__)
 #    define _LIBCPP_USING_GETENTROPY

diff  --git a/libcxx/include/__cxx03/__config b/libcxx/include/__cxx03/__config
index 9845b7aa8742e..46c7c4440e7b9 100644
--- a/libcxx/include/__cxx03/__config
+++ b/libcxx/include/__cxx03/__config
@@ -263,7 +263,7 @@ _LIBCPP_HARDENING_MODE_DEBUG
 //      When this option is used, the token passed to `std::random_device`'s
 //      constructor *must* be "/dev/urandom" -- anything else is an error.
 #  if defined(__APPLE__) || defined(__FreeBSD__) || defined(__NetBSD__) || defined(__OpenBSD__) ||                     \
-      defined(__DragonFly__)
+      defined(__DragonFly__) || defined(__BIONIC__)
 #    define _LIBCPP_USING_ARC4_RANDOM
 #  elif defined(__wasi__) || defined(__EMSCRIPTEN__)
 #    define _LIBCPP_USING_GETENTROPY

diff  --git a/libcxx/src/filesystem/operations.cpp b/libcxx/src/filesystem/operations.cpp
index 3ff62c102d0ad..3d8aa8b48e044 100644
--- a/libcxx/src/filesystem/operations.cpp
+++ b/libcxx/src/filesystem/operations.cpp
@@ -40,8 +40,10 @@
 #include <fcntl.h> /* values for fchmodat */
 #include <time.h>
 
-// since Linux 4.5 and FreeBSD 13, but the Linux libc wrapper is only provided by glibc >= 2.27 and musl
-#if _LIBCPP_GLIBC_PREREQ(2, 27) || _LIBCPP_HAS_MUSL_LIBC || defined(__FreeBSD__)
+// Since Linux 4.5 and FreeBSD 13, but the Linux libc wrapper is only provided
+// by glibc >= 2.27, musl, and Bionic.
+#if _LIBCPP_GLIBC_PREREQ(2, 27) || _LIBCPP_HAS_MUSL_LIBC || defined(__FreeBSD__) ||                                    \
+    (defined(__BIONIC__) && __ANDROID_API__ >= 34)
 #  define _LIBCPP_FILESYSTEM_USE_COPY_FILE_RANGE
 #endif
 
@@ -564,7 +566,7 @@ void __create_symlink(path const& from, path const& to, error_code* ec) {
 path __current_path(error_code* ec) {
   ErrorHandler<path> err("current_path", ec);
 
-#if defined(_WIN32) || defined(__GLIBC__) || defined(__APPLE__)
+#if defined(_WIN32) || defined(__GLIBC__) || defined(__APPLE__) || defined(__BIONIC__)
   // Common extension outside of POSIX getcwd() spec, without needing to
   // preallocate a buffer. Also supported by a number of other POSIX libcs.
   int size              = 0;