[libcxx-commits] [libcxx] [libc++][AIX] Support file offsets larger than 2GB in basic_filebuf on 32-bit (PR #215892)

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llvmorg-github-actions[bot] wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-libcxx

Author: Jake Egan (jakeegan)

<details>
<summary>Changes</summary>

Currently, opening files greater than 2GB on 32-bit AIX doesn't work, even with the `_LARGE_FILES` macro defined in the user program. Instead of building libc++ with `_LARGE_FILES`, we can swap `fopen`/`fseeko`/`ftello` calls with their 64-bit counter-parts.

---
Full diff: https://github.com/llvm/llvm-project/pull/215892.diff


2 Files Affected:

- (modified) libcxx/include/fstream (+15-1) 
- (modified) libcxx/test/std/input.output/file.streams/fstreams/ifstream.members/offset_range.pass.cpp (+3-3) 


``````````diff
diff --git a/libcxx/include/fstream b/libcxx/include/fstream
index 0023191166c3b..a47b899857e4e 100644
--- a/libcxx/include/fstream
+++ b/libcxx/include/fstream
@@ -432,6 +432,7 @@ private:
 
   _LIBCPP_HIDE_FROM_ABI static int __fseek(FILE* __file, pos_type __offset, int __whence);
   _LIBCPP_HIDE_FROM_ABI static pos_type __ftell(FILE* __file);
+  _LIBCPP_HIDE_FROM_ABI static FILE* __fopen(const char* __name, const char* __mode);
 
   _LIBCPP_EXPORTED_FROM_ABI friend FILE* __get_ostream_file(ostream&);
 
@@ -779,6 +780,15 @@ const wchar_t* basic_filebuf<_CharT, _Traits>::__make_mdwstring(ios_base::openmo
 }
 #    endif
 
+template <class _CharT, class _Traits>
+FILE* basic_filebuf<_CharT, _Traits>::__fopen(const char* __name, const char* __mode) {
+#    if defined(_AIX) && !defined(__64BIT__)
+  return fopen64(__name, __mode);
+#    else
+  return std::fopen(__name, __mode);
+#    endif
+}
+
 template <class _CharT, class _Traits>
 basic_filebuf<_CharT, _Traits>* basic_filebuf<_CharT, _Traits>::open(const char* __s, ios_base::openmode __mode) {
   if (__file_)
@@ -787,7 +797,7 @@ basic_filebuf<_CharT, _Traits>* basic_filebuf<_CharT, _Traits>::open(const char*
   if (!__mdstr)
     return nullptr;
 
-  return __adopt_file(std::fopen(__s, __mdstr), __mode);
+  return __adopt_file(__fopen(__s, __mdstr), __mode);
 }
 
 template <class _CharT, class _Traits>
@@ -1067,6 +1077,8 @@ int basic_filebuf<_CharT, _Traits>::__fseek(FILE* __file, pos_type __offset, int
   return _fseeki64(__file, __offset, __whence);
 #    elif _LIBCPP_LIBC_NEWLIB
   return fseek(__file, __offset, __whence);
+#    elif defined(_AIX) && !defined(__64BIT__)
+  return fseeko64(__file, __offset, __whence);
 #    else
   return ::fseeko(__file, __offset, __whence);
 #    endif
@@ -1078,6 +1090,8 @@ typename basic_filebuf<_CharT, _Traits>::pos_type basic_filebuf<_CharT, _Traits>
   return _ftelli64(__file);
 #    elif _LIBCPP_LIBC_NEWLIB
   return ftell(__file);
+#    elif defined(_AIX) && !defined(__64BIT__)
+  return ftello64(__file);
 #    else
   return ftello(__file);
 #    endif
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/ifstream.members/offset_range.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/ifstream.members/offset_range.pass.cpp
index d176059ff87bf..7a11378541c1d 100644
--- a/libcxx/test/std/input.output/file.streams/fstreams/ifstream.members/offset_range.pass.cpp
+++ b/libcxx/test/std/input.output/file.streams/fstreams/ifstream.members/offset_range.pass.cpp
@@ -18,10 +18,10 @@
 //
 // XFAIL: target={{i686|arm.*}}-{{.+}}-android{{.*}}
 
-// By default, off_t is typically a 32-bit integer on ARMv7 Linux systems and
-// 32-bit AIX, meaning it can represent file sizes up to 2GB (2^31 bytes) only.
+// By default, off_t is typically a 32-bit integer on ARMv7 Linux systems,
+// meaning it can represent file sizes up to 2GB (2^31 bytes) only.
 //
-// UNSUPPORTED: target=armv7-unknown-linux-gnueabihf, target=powerpc-{{.+}}-aix{{.*}}
+// UNSUPPORTED: target=armv7-unknown-linux-gnueabihf
 
 #include <fstream>
 #include <iostream>

``````````

</details>


https://github.com/llvm/llvm-project/pull/215892