Make support for thread-unsafe C functions optional.
One of the aspects of CloudABI is that it aims to help you write code
that is thread-safe out of the box. This is very important if you want
to write libraries that are easy to reuse. For CloudABI we decided to
not provide the thread-unsafe functions. So far this is working out
pretty well, as thread-unsafety issues are detected really early on.
The following patch adds a knob to libc++,
_LIBCPP_HAS_NO_THREAD_UNSAFE_C_FUNCTIONS, that can be set to disable
thread-unsafe functions that can easily be avoided in practice. The
following functions are not thread-safe:
- <clocale>: locale handles should be preferred over setlocale().
- <cstdlib>: mbrlen(), mbrtowc() and wcrtomb() should be preferred over
their non-restartable counterparts.
- <ctime>: asctime(), ctime(), gmtime() and localtime() are not
thread-safe. The first two are also deprecated by POSIX.
Differential Revision: http://reviews.llvm.org/D8703
Reviewed by: marshall
llvm-svn: 240527
Cr-Mirrored-From: sso://chromium.googlesource.com/_direct/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: e0cf3b9a3ca8d80d313d1e2e5b8c70d73d10e933
diff --git a/include/__config b/include/__config
index adf11d3..62efbf8 100644
--- a/include/__config
+++ b/include/__config
@@ -766,4 +766,10 @@
#define _LIBCPP_PROVIDES_DEFAULT_RUNE_TABLE
#endif
+// Thread-unsafe functions such as strtok(), mbtowc() and localtime()
+// are not available.
+#ifdef __CloudABI__
+#define _LIBCPP_HAS_NO_THREAD_UNSAFE_C_FUNCTIONS
+#endif
+
#endif // _LIBCPP_CONFIG
diff --git a/include/clocale b/include/clocale
index f8b8f0d..05fa9c6 100644
--- a/include/clocale
+++ b/include/clocale
@@ -45,7 +45,9 @@
_LIBCPP_BEGIN_NAMESPACE_STD
using ::lconv;
+#ifndef _LIBCPP_HAS_NO_THREAD_UNSAFE_C_FUNCTIONS
using ::setlocale;
+#endif
using ::localeconv;
_LIBCPP_END_NAMESPACE_STD
diff --git a/include/cstdlib b/include/cstdlib
index 298040e..55e15c8 100644
--- a/include/cstdlib
+++ b/include/cstdlib
@@ -147,9 +147,11 @@
#undef lldiv
using ::lldiv;
#endif // _LIBCPP_HAS_NO_LONG_LONG
+#ifndef _LIBCPP_HAS_NO_THREAD_UNSAFE_C_FUNCTIONS
using ::mblen;
using ::mbtowc;
using ::wctomb;
+#endif
using ::mbstowcs;
using ::wcstombs;
#ifdef _LIBCPP_HAS_QUICK_EXIT
diff --git a/include/cstring b/include/cstring
index 21c9155..d60b992 100644
--- a/include/cstring
+++ b/include/cstring
@@ -102,7 +102,9 @@
inline _LIBCPP_INLINE_VISIBILITY char* strstr( char* __s1, const char* __s2) {return ::strstr(__s1, __s2);}
#endif
+#ifndef _LIBCPP_HAS_NO_THREAD_UNSAFE_C_FUNCTIONS
using ::strtok;
+#endif
using ::memset;
using ::strerror;
using ::strlen;
diff --git a/include/ctime b/include/ctime
index fc4eb26..da9e329 100644
--- a/include/ctime
+++ b/include/ctime
@@ -61,10 +61,12 @@
using ::difftime;
using ::mktime;
using ::time;
+#ifndef _LIBCPP_HAS_NO_THREAD_UNSAFE_C_FUNCTIONS
using ::asctime;
using ::ctime;
using ::gmtime;
using ::localtime;
+#endif
using ::strftime;
_LIBCPP_END_NAMESPACE_STD