Revert "[Support] Add RetryAfterSignal helper function" and subsequent fix

The fix in r306003 uncovered a pretty fundamental problem that libc++
implementation of std::result_of does not handle the prototype of
open(2) correctly (presumably because it contains ...). This makes the
whole function unusable in its current form, so I am also reverting the
original commit (r305892), which introduced the function, at least until
I figure out a way to solve the libc++ issue.

llvm-svn: 306005

3 files changed, 25 insertions, 12 deletions

diff --git a/llvm/lib/Support/MemoryBuffer.cpp b/llvm/lib/Support/MemoryBuffer.cpp
index 85e782b2c04..227e792d83d 100644
--- a/llvm/lib/Support/MemoryBuffer.cpp
+++ b/llvm/lib/Support/MemoryBuffer.cpp
@@ -240,9 +240,11 @@ getMemoryBufferForStream(int FD, const Twine &BufferName) {
   // Read into Buffer until we hit EOF.
   do {
     Buffer.reserve(Buffer.size() + ChunkSize);
-    ReadBytes = sys::RetryAfterSignal(-1, read, FD, Buffer.end(), ChunkSize);
-    if (ReadBytes == -1)
+    ReadBytes = read(FD, Buffer.end(), ChunkSize);
+    if (ReadBytes == -1) {
+      if (errno == EINTR) continue;
       return std::error_code(errno, std::generic_category());
+    }
     Buffer.set_size(Buffer.size() + ReadBytes);
   } while (ReadBytes != 0);
 
@@ -389,12 +391,13 @@ getOpenFileImpl(int FD, const Twine &Filename, uint64_t FileSize,
 
   while (BytesLeft) {
 #ifdef HAVE_PREAD
-    ssize_t NumRead = sys::RetryAfterSignal(-1, ::pread, FD, BufPtr, BytesLeft,
-                                            MapSize - BytesLeft + Offset);
+    ssize_t NumRead = ::pread(FD, BufPtr, BytesLeft, MapSize-BytesLeft+Offset);
 #else
-    ssize_t NumRead = sys::RetryAfterSignal(-1, ::read, FD, BufPtr, BytesLeft);
+    ssize_t NumRead = ::read(FD, BufPtr, BytesLeft);
 #endif
     if (NumRead == -1) {
+      if (errno == EINTR)
+        continue;
       // Error while reading.
       return std::error_code(errno, std::generic_category());
     }
diff --git a/llvm/lib/Support/Unix/Path.inc b/llvm/lib/Support/Unix/Path.inc
index 45097eb918b..b6774692595 100644
--- a/llvm/lib/Support/Unix/Path.inc
+++ b/llvm/lib/Support/Unix/Path.inc
@@ -737,8 +737,10 @@ std::error_code openFileForRead(const Twine &Name, int &ResultFD,
 #ifdef O_CLOEXEC
   OpenFlags |= O_CLOEXEC;
 #endif
-  if ((ResultFD = sys::RetryAfterSignal(-1, open, P.begin(), OpenFlags)) < 0)
-    return std::error_code(errno, std::generic_category());
+  while ((ResultFD = open(P.begin(), OpenFlags)) < 0) {
+    if (errno != EINTR)
+      return std::error_code(errno, std::generic_category());
+  }
 #ifndef O_CLOEXEC
   int r = fcntl(ResultFD, F_SETFD, FD_CLOEXEC);
   (void)r;
@@ -798,8 +800,10 @@ std::error_code openFileForWrite(const Twine &Name, int &ResultFD,
 
   SmallString<128> Storage;
   StringRef P = Name.toNullTerminatedStringRef(Storage);
-  if ((ResultFD = sys::RetryAfterSignal(-1, open, P.begin(), OpenFlags, Mode)) < 0)
-    return std::error_code(errno, std::generic_category());
+  while ((ResultFD = open(P.begin(), OpenFlags, Mode)) < 0) {
+    if (errno != EINTR)
+      return std::error_code(errno, std::generic_category());
+  }
 #ifndef O_CLOEXEC
   int r = fcntl(ResultFD, F_SETFD, FD_CLOEXEC);
   (void)r;
diff --git a/llvm/lib/Support/Unix/Process.inc b/llvm/lib/Support/Unix/Process.inc
index 2d466209468..1d0143c6716 100644
--- a/llvm/lib/Support/Unix/Process.inc
+++ b/llvm/lib/Support/Unix/Process.inc
@@ -207,10 +207,13 @@ std::error_code Process::FixupStandardFileDescriptors() {
   for (int StandardFD : StandardFDs) {
     struct stat st;
     errno = 0;
-    if (RetryAfterSignal(-1, fstat, StandardFD, &st) < 0) {
+    while (fstat(StandardFD, &st) < 0) {
       assert(errno && "expected errno to be set if fstat failed!");
       // fstat should return EBADF if the file descriptor is closed.
-      if (errno != EBADF)
+      if (errno == EBADF)
+        break;
+      // retry fstat if we got EINTR, otherwise bubble up the failure.
+      if (errno != EINTR)
         return std::error_code(errno, std::generic_category());
     }
     // if fstat succeeds, move on to the next FD.
@@ -219,8 +222,11 @@ std::error_code Process::FixupStandardFileDescriptors() {
     assert(errno == EBADF && "expected errno to have EBADF at this point!");
 
     if (NullFD < 0) {
-      if ((NullFD = RetryAfterSignal(-1, open, "/dev/null", O_RDWR)) < 0)
+      while ((NullFD = open("/dev/null", O_RDWR)) < 0) {
+        if (errno == EINTR)
+          continue;
         return std::error_code(errno, std::generic_category());
+      }
     }
 
     if (NullFD == StandardFD)