Drop an unnecessary use of writev.
It looks like the code this patch deletes is based on a misunderstanding of
what guarantees writev provides. In particular, writev with 1 iovec is
not "more atomic" than a write.
Testing on OS X shows that both write and writev from multiple processes
can be intermixed.
llvm-svn: 255837
diff --git a/llvm/lib/Support/raw_ostream.cpp b/llvm/lib/Support/raw_ostream.cpp
index 49ef400..57c7ac3 100644
--- a/llvm/lib/Support/raw_ostream.cpp
+++ b/llvm/lib/Support/raw_ostream.cpp
@@ -517,7 +517,7 @@
/// closes the file when the stream is destroyed.
raw_fd_ostream::raw_fd_ostream(int fd, bool shouldClose, bool unbuffered)
: raw_pwrite_stream(unbuffered), FD(fd), ShouldClose(shouldClose),
- Error(false), UseAtomicWrites(false) {
+ Error(false) {
if (FD < 0 ) {
ShouldClose = false;
return;
@@ -568,21 +568,7 @@
pos += Size;
do {
- ssize_t ret;
-
- // Check whether we should attempt to use atomic writes.
- if (LLVM_LIKELY(!UseAtomicWrites)) {
- ret = ::write(FD, Ptr, Size);
- } else {
- // Use ::writev() where available.
-#if defined(HAVE_WRITEV)
- const void *Addr = static_cast<const void *>(Ptr);
- struct iovec IOV = {const_cast<void *>(Addr), Size };
- ret = ::writev(FD, &IOV, 1);
-#else
- ret = ::write(FD, Ptr, Size);
-#endif
- }
+ ssize_t ret = ::write(FD, Ptr, Size);
if (ret < 0) {
// If it's a recoverable error, swallow it and retry the write.