8 files changed, 449 insertions, 166 deletions

diff --git a/lib/Support/Unix/Host.inc b/lib/Support/Unix/Host.inc
index c5d36ff..fcb3638 100644
--- a/lib/Support/Unix/Host.inc
+++ b/lib/Support/Unix/Host.inc
@@ -1,4 +1,4 @@
- //===- llvm/Support/Unix/Host.inc -------------------------------*- C++ -*-===//
+//===- llvm/Support/Unix/Host.inc -------------------------------*- C++ -*-===//
 //
 //                     The LLVM Compiler Infrastructure
 //
@@ -22,7 +22,6 @@
 #include <sys/utsname.h>
 #include <cctype>
 #include <string>
-#include <cstdlib> // ::getenv
 
 using namespace llvm;
 
@@ -39,7 +38,8 @@ std::string sys::getDefaultTargetTriple() {
   StringRef TargetTripleString(LLVM_DEFAULT_TARGET_TRIPLE);
   std::pair<StringRef, StringRef> ArchSplit = TargetTripleString.split('-');
 
-  // Normalize the arch, since the target triple may not actually match the target.
+  // Normalize the arch, since the target triple may not actually match the
+  // target.
   std::string Arch = ArchSplit.first;
 
   std::string Triple(Arch);
diff --git a/lib/Support/Unix/Path.inc b/lib/Support/Unix/Path.inc
index 623547a..634d404 100644
--- a/lib/Support/Unix/Path.inc
+++ b/lib/Support/Unix/Path.inc
@@ -87,22 +87,6 @@ namespace {
   };
 }
 
-static std::error_code TempDir(SmallVectorImpl<char> &result) {
-  // FIXME: Don't use TMPDIR if program is SUID or SGID enabled.
-  const char *dir = nullptr;
-  (dir = std::getenv("TMPDIR")) || (dir = std::getenv("TMP")) ||
-      (dir = std::getenv("TEMP")) || (dir = std::getenv("TEMPDIR")) ||
-#ifdef P_tmpdir
-      (dir = P_tmpdir) ||
-#endif
-      (dir = "/tmp");
-
-  result.clear();
-  StringRef d(dir);
-  result.append(d.begin(), d.end());
-  return std::error_code();
-}
-
 namespace llvm {
 namespace sys  {
 namespace fs {
@@ -272,19 +256,6 @@ std::error_code create_directory(const Twine &path, bool IgnoreExisting) {
   return std::error_code();
 }
 
-std::error_code normalize_separators(SmallVectorImpl<char> &Path) {
-  for (auto PI = Path.begin(), PE = Path.end(); PI < PE; ++PI) {
-    if (*PI == '\\') {
-      auto PN = PI + 1;
-      if (PN < PE && *PN == '\\')
-        ++PI; // increment once, the for loop will move over the escaped slash
-      else
-        *PI = '/';
-    }
-  }
-  return std::error_code();
-}
-
 // Note that we are using symbolic link because hard links are not supported by
 // all filesystems (SMB doesn't).
 std::error_code create_link(const Twine &to, const Twine &from) {
@@ -350,38 +321,35 @@ std::error_code resize_file(const Twine &path, uint64_t size) {
   return std::error_code();
 }
 
-std::error_code exists(const Twine &path, bool &result) {
-  SmallString<128> path_storage;
-  StringRef p = path.toNullTerminatedStringRef(path_storage);
-
-  if (::access(p.begin(), F_OK) == -1) {
-    if (errno != ENOENT)
-      return std::error_code(errno, std::generic_category());
-    result = false;
-  } else
-    result = true;
-
-  return std::error_code();
+static int convertAccessMode(AccessMode Mode) {
+  switch (Mode) {
+  case AccessMode::Exist:
+    return F_OK;
+  case AccessMode::Write:
+    return W_OK;
+  case AccessMode::Execute:
+    return R_OK | X_OK; // scripts also need R_OK.
+  }
+  llvm_unreachable("invalid enum");
 }
 
-bool can_write(const Twine &Path) {
+std::error_code access(const Twine &Path, AccessMode Mode) {
   SmallString<128> PathStorage;
   StringRef P = Path.toNullTerminatedStringRef(PathStorage);
-  return 0 == access(P.begin(), W_OK);
-}
 
-bool can_execute(const Twine &Path) {
-  SmallString<128> PathStorage;
-  StringRef P = Path.toNullTerminatedStringRef(PathStorage);
+  if (::access(P.begin(), convertAccessMode(Mode)) == -1)
+    return std::error_code(errno, std::generic_category());
 
-  if (0 != access(P.begin(), R_OK | X_OK))
-    return false;
-  struct stat buf;
-  if (0 != stat(P.begin(), &buf))
-    return false;
-  if (!S_ISREG(buf.st_mode))
-    return false;
-  return true;
+  if (Mode == AccessMode::Execute) {
+    // Don't say that directories are executable.
+    struct stat buf;
+    if (0 != stat(P.begin(), &buf))
+      return errc::permission_denied;
+    if (!S_ISREG(buf.st_mode))
+      return errc::permission_denied;
+  }
+
+  return std::error_code();
 }
 
 bool equivalent(file_status A, file_status B) {
@@ -678,6 +646,66 @@ bool home_directory(SmallVectorImpl<char> &result) {
   return false;
 }
 
+static const char *getEnvTempDir() {
+  // Check whether the temporary directory is specified by an environment
+  // variable.
+  const char *EnvironmentVariables[] = {"TMPDIR", "TMP", "TEMP", "TEMPDIR"};
+  for (const char *Env : EnvironmentVariables) {
+    if (const char *Dir = std::getenv(Env))
+      return Dir;
+  }
+
+  return nullptr;
+}
+
+static const char *getDefaultTempDir(bool ErasedOnReboot) {
+#ifdef P_tmpdir
+  if ((bool)P_tmpdir)
+    return P_tmpdir;
+#endif
+
+  if (ErasedOnReboot)
+    return "/tmp";
+  return "/var/tmp";
+}
+
+void system_temp_directory(bool ErasedOnReboot, SmallVectorImpl<char> &Result) {
+  Result.clear();
+
+  if (ErasedOnReboot) {
+    // There is no env variable for the cache directory.
+    if (const char *RequestedDir = getEnvTempDir()) {
+      Result.append(RequestedDir, RequestedDir + strlen(RequestedDir));
+      return;
+    }
+  }
+
+#if defined(_CS_DARWIN_USER_TEMP_DIR) && defined(_CS_DARWIN_USER_CACHE_DIR)
+  // On Darwin, use DARWIN_USER_TEMP_DIR or DARWIN_USER_CACHE_DIR.
+  // macros defined in <unistd.h> on darwin >= 9
+  int ConfName = ErasedOnReboot? _CS_DARWIN_USER_TEMP_DIR
+                               : _CS_DARWIN_USER_CACHE_DIR;
+  size_t ConfLen = confstr(ConfName, nullptr, 0);
+  if (ConfLen > 0) {
+    do {
+      Result.resize(ConfLen);
+      ConfLen = confstr(ConfName, Result.data(), Result.size());
+    } while (ConfLen > 0 && ConfLen != Result.size());
+
+    if (ConfLen > 0) {
+      assert(Result.back() == 0);
+      Result.pop_back();
+      return;
+    }
+
+    Result.clear();
+  }
+#endif
+
+  const char *RequestedDir = getDefaultTempDir(ErasedOnReboot);
+  Result.append(RequestedDir, RequestedDir + strlen(RequestedDir));
+}
+
 } // end namespace path
 
 } // end namespace sys
diff --git a/lib/Support/Unix/Process.inc b/lib/Support/Unix/Process.inc
index d2c5dbc..a429bb3 100644
--- a/lib/Support/Unix/Process.inc
+++ b/lib/Support/Unix/Process.inc
@@ -14,15 +14,25 @@
 #include "Unix.h"
 #include "llvm/ADT/Hashing.h"
 #include "llvm/ADT/StringRef.h"
+#include "llvm/Support/ManagedStatic.h"
 #include "llvm/Support/Mutex.h"
 #include "llvm/Support/MutexGuard.h"
 #include "llvm/Support/TimeValue.h"
+#if HAVE_FCNTL_H
+#include <fcntl.h>
+#endif
 #ifdef HAVE_SYS_TIME_H
 #include <sys/time.h>
 #endif
 #ifdef HAVE_SYS_RESOURCE_H
 #include <sys/resource.h>
 #endif
+#ifdef HAVE_SYS_STAT_H
+#include <sys/stat.h>
+#endif
+#if HAVE_SIGNAL_H
+#include <signal.h>
+#endif
 // DragonFlyBSD, OpenBSD, and Bitrig have deprecated <malloc.h> for
 // <stdlib.h> instead. Unix.h includes this for us already.
 #if defined(HAVE_MALLOC_H) && !defined(__DragonFly__) && \
@@ -198,6 +208,97 @@ Process::GetArgumentVector(SmallVectorImpl<const char *> &ArgsOut,
   return std::error_code();
 }
 
+namespace {
+class FDCloser {
+public:
+  FDCloser(int &FD) : FD(FD), KeepOpen(false) {}
+  void keepOpen() { KeepOpen = true; }
+  ~FDCloser() {
+    if (!KeepOpen && FD >= 0)
+      ::close(FD);
+  }
+
+private:
+  FDCloser(const FDCloser &) LLVM_DELETED_FUNCTION;
+  void operator=(const FDCloser &) LLVM_DELETED_FUNCTION;
+
+  int &FD;
+  bool KeepOpen;
+};
+}
+
+std::error_code Process::FixupStandardFileDescriptors() {
+  int NullFD = -1;
+  FDCloser FDC(NullFD);
+  const int StandardFDs[] = {STDIN_FILENO, STDOUT_FILENO, STDERR_FILENO};
+  for (int StandardFD : StandardFDs) {
+    struct stat st;
+    errno = 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)
+        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.
+    if (!errno)
+      continue;
+    assert(errno == EBADF && "expected errno to have EBADF at this point!");
+
+    if (NullFD < 0) {
+      while ((NullFD = open("/dev/null", O_RDWR)) < 0) {
+        if (errno == EINTR)
+          continue;
+        return std::error_code(errno, std::generic_category());
+      }
+    }
+
+    if (NullFD == StandardFD)
+      FDC.keepOpen();
+    else if (dup2(NullFD, StandardFD) < 0)
+      return std::error_code(errno, std::generic_category());
+  }
+  return std::error_code();
+}
+
+std::error_code Process::SafelyCloseFileDescriptor(int FD) {
+  // Create a signal set filled with *all* signals.
+  sigset_t FullSet;
+  if (sigfillset(&FullSet) < 0)
+    return std::error_code(errno, std::generic_category());
+  // Atomically swap our current signal mask with a full mask.
+  sigset_t SavedSet;
+#if LLVM_ENABLE_THREADS
+  if (int EC = pthread_sigmask(SIG_SETMASK, &FullSet, &SavedSet))
+    return std::error_code(EC, std::generic_category());
+#else
+  if (sigprocmask(SIG_SETMASK, &FullSet, &SavedSet) < 0)
+    return std::error_code(errno, std::generic_category());
+#endif
+  // Attempt to close the file descriptor.
+  // We need to save the error, if one occurs, because our subsequent call to
+  // pthread_sigmask might tamper with errno.
+  int ErrnoFromClose = 0;
+  if (::close(FD) < 0)
+    ErrnoFromClose = errno;
+  // Restore the signal mask back to what we saved earlier.
+  int EC = 0;
+#if LLVM_ENABLE_THREADS
+  EC = pthread_sigmask(SIG_SETMASK, &SavedSet, nullptr);
+#else
+  if (sigprocmask(SIG_SETMASK, &SavedSet, nullptr) < 0)
+    EC = errno;
+#endif
+  // The error code from close takes precedence over the one from
+  // pthread_sigmask.
+  if (ErrnoFromClose)
+    return std::error_code(ErrnoFromClose, std::generic_category());
+  return std::error_code(EC, std::generic_category());
+}
+
 bool Process::StandardInIsUserInput() {
   return FileDescriptorIsDisplayed(STDIN_FILENO);
 }
@@ -263,11 +364,14 @@ extern "C" int del_curterm(struct term *termp);
 extern "C" int tigetnum(char *capname);
 #endif
 
+#ifdef HAVE_TERMINFO
+static ManagedStatic<sys::Mutex> TermColorMutex;
+#endif
+
 static bool terminalHasColors(int fd) {
 #ifdef HAVE_TERMINFO
   // First, acquire a global lock because these C routines are thread hostile.
-  static sys::Mutex M;
-  MutexGuard G(M);
+  MutexGuard G(*TermColorMutex);
 
   int errret = 0;
   if (setupterm((char *)nullptr, fd, &errret) != 0)
diff --git a/lib/Support/Unix/Program.inc b/lib/Support/Unix/Program.inc
index 06a33cd..0670ad3 100644
--- a/lib/Support/Unix/Program.inc
+++ b/lib/Support/Unix/Program.inc
@@ -17,8 +17,10 @@
 //===----------------------------------------------------------------------===//
 
 #include "Unix.h"
+#include "llvm/ADT/StringExtras.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/FileSystem.h"
+#include "llvm/Support/raw_ostream.h"
 #include <llvm/Config/config.h>
 #if HAVE_SYS_STAT_H
 #include <sys/stat.h>
@@ -53,50 +55,31 @@ using namespace sys;
 
 ProcessInfo::ProcessInfo() : Pid(0), ReturnCode(0) {}
 
-// This function just uses the PATH environment variable to find the program.
-std::string
-sys::FindProgramByName(const std::string& progName) {
-
-  // Check some degenerate cases
-  if (progName.length() == 0) // no program
-    return "";
-  std::string temp = progName;
+ErrorOr<std::string> sys::findProgramByName(StringRef Name,
+                                            ArrayRef<StringRef> Paths) {
+  assert(!Name.empty() && "Must have a name!");
   // Use the given path verbatim if it contains any slashes; this matches
   // the behavior of sh(1) and friends.
-  if (progName.find('/') != std::string::npos)
-    return temp;
-
-  // At this point, the file name is valid and does not contain slashes. Search
-  // for it through the directories specified in the PATH environment variable.
+  if (Name.find('/') != StringRef::npos)
+    return std::string(Name);
 
-  // Get the path. If its empty, we can't do anything to find it.
-  const char *PathStr = getenv("PATH");
-  if (!PathStr)
-    return "";
+  if (Paths.empty()) {
+    SmallVector<StringRef, 16> SearchPaths;
+    SplitString(std::getenv("PATH"), SearchPaths, ":");
+    return findProgramByName(Name, SearchPaths);
+  }
 
-  // Now we have a colon separated list of directories to search; try them.
-  size_t PathLen = strlen(PathStr);
-  while (PathLen) {
-    // Find the first colon...
-    const char *Colon = std::find(PathStr, PathStr+PathLen, ':');
+  for (auto Path : Paths) {
+    if (Path.empty())
+      continue;
 
     // Check to see if this first directory contains the executable...
-    SmallString<128> FilePath(PathStr,Colon);
-    sys::path::append(FilePath, progName);
-    if (sys::fs::can_execute(Twine(FilePath)))
-      return FilePath.str();                    // Found the executable!
-
-    // Nope it wasn't in this directory, check the next path in the list!
-    PathLen -= Colon-PathStr;
-    PathStr = Colon;
-
-    // Advance past duplicate colons
-    while (*PathStr == ':') {
-      PathStr++;
-      PathLen--;
-    }
+    SmallString<128> FilePath(Path);
+    sys::path::append(FilePath, Name);
+    if (sys::fs::can_execute(FilePath.c_str()))
+      return std::string(FilePath.str()); // Found the executable!
   }
-  return "";
+  return std::errc::no_such_file_or_directory;
 }
 
 static bool RedirectIO(const StringRef *Path, int FD, std::string* ErrMsg) {
@@ -334,7 +317,6 @@ ProcessInfo sys::Wait(const ProcessInfo &PI, unsigned SecondsToWait,
   pid_t ChildPid = PI.Pid;
   if (WaitUntilTerminates) {
     SecondsToWait = 0;
-    ChildPid = -1; // mimic a wait() using waitpid()
   } else if (SecondsToWait) {
     // Install a timeout handler.  The handler itself does nothing, but the
     // simple fact of having a handler at all causes the wait below to return
@@ -440,6 +422,23 @@ ProcessInfo sys::Wait(const ProcessInfo &PI, unsigned SecondsToWait,
     return std::error_code();
 }
 
+std::error_code
+llvm::sys::writeFileWithEncoding(StringRef FileName, StringRef Contents,
+                                 WindowsEncodingMethod Encoding /*unused*/) {
+  std::error_code EC;
+  llvm::raw_fd_ostream OS(FileName, EC, llvm::sys::fs::OpenFlags::F_Text);
+
+  if (EC)
+    return EC;
+
+  OS << Contents;
+
+  if (OS.has_error())
+    return std::make_error_code(std::errc::io_error);
+
+  return EC;
+}
+
 bool llvm::sys::argumentsFitWithinSystemLimits(ArrayRef<const char*> Args) {
   static long ArgMax = sysconf(_SC_ARG_MAX);
 
@@ -448,13 +447,13 @@ bool llvm::sys::argumentsFitWithinSystemLimits(ArrayRef<const char*> Args) {
     return true;
 
   // Conservatively account for space required by environment variables.
-  ArgMax /= 2;
+  long HalfArgMax = ArgMax / 2;
 
   size_t ArgLength = 0;
   for (ArrayRef<const char*>::iterator I = Args.begin(), E = Args.end();
        I != E; ++I) {
     ArgLength += strlen(*I) + 1;
-    if (ArgLength > size_t(ArgMax)) {
+    if (ArgLength > size_t(HalfArgMax)) {
       return false;
     }
   }
diff --git a/lib/Support/Unix/RWMutex.inc b/lib/Support/Unix/RWMutex.inc
index edcbd52..85a1043 100644
--- a/lib/Support/Unix/RWMutex.inc
+++ b/lib/Support/Unix/RWMutex.inc
@@ -26,26 +26,26 @@ using namespace sys;
 // will therefore deadlock if a thread tries to acquire a read lock
 // multiple times.
 
-RWMutexImpl::RWMutexImpl() : data_(new Mutex(false)) { }
+RWMutexImpl::RWMutexImpl() : data_(new MutexImpl(false)) { }
 
 RWMutexImpl::~RWMutexImpl() {
-  delete static_cast<Mutex *>(data_);
+  delete static_cast<MutexImpl *>(data_);
 }
 
 bool RWMutexImpl::reader_acquire() {
-  return static_cast<Mutex *>(data_)->acquire();
+  return static_cast<MutexImpl *>(data_)->acquire();
 }
 
 bool RWMutexImpl::reader_release() {
-  return static_cast<Mutex *>(data_)->release();
+  return static_cast<MutexImpl *>(data_)->release();
 }
 
 bool RWMutexImpl::writer_acquire() {
-  return static_cast<Mutex *>(data_)->acquire();
+  return static_cast<MutexImpl *>(data_)->acquire();
 }
 
 bool RWMutexImpl::writer_release() {
-  return static_cast<Mutex *>(data_)->release();
+  return static_cast<MutexImpl *>(data_)->release();
 }
 
 }
diff --git a/lib/Support/Unix/Signals.inc b/lib/Support/Unix/Signals.inc
index 1841fea..e8f4643 100644
--- a/lib/Support/Unix/Signals.inc
+++ b/lib/Support/Unix/Signals.inc
@@ -14,7 +14,14 @@
 
 #include "Unix.h"
 #include "llvm/ADT/STLExtras.h"
+#include "llvm/Support/FileSystem.h"
+#include "llvm/Support/FileUtilities.h"
+#include "llvm/Support/ManagedStatic.h"
+#include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/Mutex.h"
+#include "llvm/Support/Program.h"
+#include "llvm/Support/UniqueLock.h"
+#include "llvm/Support/raw_ostream.h"
 #include <algorithm>
 #include <string>
 #include <vector>
@@ -36,18 +43,22 @@
 #if HAVE_MACH_MACH_H
 #include <mach/mach.h>
 #endif
+#if HAVE_LINK_H
+#include <link.h>
+#endif
 
 using namespace llvm;
 
 static RETSIGTYPE SignalHandler(int Sig);  // defined below.
 
-static SmartMutex<true> SignalsMutex;
+static ManagedStatic<SmartMutex<true> > SignalsMutex;
 
 /// InterruptFunction - The function to call if ctrl-c is pressed.
 static void (*InterruptFunction)() = nullptr;
 
-static std::vector<std::string> FilesToRemove;
-static std::vector<std::pair<void(*)(void*), void*> > CallBacksToRun;
+static ManagedStatic<std::vector<std::string>> FilesToRemove;
+static ManagedStatic<std::vector<std::pair<void (*)(void *), void *>>>
+    CallBacksToRun;
 
 // IntSigs - Signals that represent requested termination. There's no bug
 // or failure, or if there is, it's not our direct responsibility. For whatever
@@ -55,7 +66,6 @@ static std::vector<std::pair<void(*)(void*), void*> > CallBacksToRun;
 static const int IntSigs[] = {
   SIGHUP, SIGINT, SIGPIPE, SIGTERM, SIGUSR1, SIGUSR2
 };
-static const int *const IntSigsEnd = std::end(IntSigs);
 
 // KillSigs - Signals that represent that we have a bug, and our prompt
 // termination has been ordered.
@@ -74,7 +84,6 @@ static const int KillSigs[] = {
   , SIGEMT
 #endif
 };
-static const int *const KillSigsEnd = std::end(KillSigs);
 
 static unsigned NumRegisteredSignals = 0;
 static struct {
@@ -105,8 +114,8 @@ static void RegisterHandlers() {
   // If the handlers are already registered, we're done.
   if (NumRegisteredSignals != 0) return;
 
-  std::for_each(IntSigs, IntSigsEnd, RegisterHandler);
-  std::for_each(KillSigs, KillSigsEnd, RegisterHandler);
+  for (auto S : IntSigs) RegisterHandler(S);
+  for (auto S : KillSigs) RegisterHandler(S);
 }
 
 static void UnregisterHandlers() {
@@ -125,11 +134,12 @@ static void UnregisterHandlers() {
 static void RemoveFilesToRemove() {
   // We avoid iterators in case of debug iterators that allocate or release
   // memory.
-  for (unsigned i = 0, e = FilesToRemove.size(); i != e; ++i) {
+  std::vector<std::string>& FilesToRemoveRef = *FilesToRemove;
+  for (unsigned i = 0, e = FilesToRemoveRef.size(); i != e; ++i) {
     // We rely on a std::string implementation for which repeated calls to
     // 'c_str()' don't allocate memory. We pre-call 'c_str()' on all of these
     // strings to try to ensure this is safe.
-    const char *path = FilesToRemove[i].c_str();
+    const char *path = FilesToRemoveRef[i].c_str();
 
     // Get the status so we can determine if it's a file or directory. If we
     // can't stat the file, ignore it.
@@ -162,28 +172,31 @@ static RETSIGTYPE SignalHandler(int Sig) {
   sigfillset(&SigMask);
   sigprocmask(SIG_UNBLOCK, &SigMask, nullptr);
 
-  SignalsMutex.acquire();
-  RemoveFilesToRemove();
-
-  if (std::find(IntSigs, IntSigsEnd, Sig) != IntSigsEnd) {
-    if (InterruptFunction) {
-      void (*IF)() = InterruptFunction;
-      SignalsMutex.release();
-      InterruptFunction = nullptr;
-      IF();        // run the interrupt function.
+  {
+    unique_lock<SmartMutex<true>> Guard(*SignalsMutex);
+    RemoveFilesToRemove();
+
+    if (std::find(std::begin(IntSigs), std::end(IntSigs), Sig)
+        != std::end(IntSigs)) {
+      if (InterruptFunction) {
+        void (*IF)() = InterruptFunction;
+        Guard.unlock();
+        InterruptFunction = nullptr;
+        IF();        // run the interrupt function.
+        return;
+      }
+
+      Guard.unlock();
+      raise(Sig);   // Execute the default handler.
       return;
-    }
-
-    SignalsMutex.release();
-    raise(Sig);   // Execute the default handler.
-    return;
+   }
   }
 
-  SignalsMutex.release();
-
   // Otherwise if it is a fault (like SEGV) run any handler.
-  for (unsigned i = 0, e = CallBacksToRun.size(); i != e; ++i)
-    CallBacksToRun[i].first(CallBacksToRun[i].second);
+  std::vector<std::pair<void (*)(void *), void *>>& CallBacksToRunRef =
+      *CallBacksToRun;
+  for (unsigned i = 0, e = CallBacksToRun->size(); i != e; ++i)
+    CallBacksToRunRef[i].first(CallBacksToRunRef[i].second);
 
 #ifdef __s390__
   // On S/390, certain signals are delivered with PSW Address pointing to
@@ -196,37 +209,39 @@ static RETSIGTYPE SignalHandler(int Sig) {
 }
 
 void llvm::sys::RunInterruptHandlers() {
-  SignalsMutex.acquire();
+  sys::SmartScopedLock<true> Guard(*SignalsMutex);
   RemoveFilesToRemove();
-  SignalsMutex.release();
 }
 
 void llvm::sys::SetInterruptFunction(void (*IF)()) {
-  SignalsMutex.acquire();
-  InterruptFunction = IF;
-  SignalsMutex.release();
+  {
+    sys::SmartScopedLock<true> Guard(*SignalsMutex);
+    InterruptFunction = IF;
+  }
   RegisterHandlers();
 }
 
 // RemoveFileOnSignal - The public API
 bool llvm::sys::RemoveFileOnSignal(StringRef Filename,
                                    std::string* ErrMsg) {
-  SignalsMutex.acquire();
-  std::string *OldPtr = FilesToRemove.empty() ? nullptr : &FilesToRemove[0];
-  FilesToRemove.push_back(Filename);
-
-  // We want to call 'c_str()' on every std::string in this vector so that if
-  // the underlying implementation requires a re-allocation, it happens here
-  // rather than inside of the signal handler. If we see the vector grow, we
-  // have to call it on every entry. If it remains in place, we only need to
-  // call it on the latest one.
-  if (OldPtr == &FilesToRemove[0])
-    FilesToRemove.back().c_str();
-  else
-    for (unsigned i = 0, e = FilesToRemove.size(); i != e; ++i)
-      FilesToRemove[i].c_str();
-
-  SignalsMutex.release();
+  {
+    sys::SmartScopedLock<true> Guard(*SignalsMutex);
+    std::vector<std::string>& FilesToRemoveRef = *FilesToRemove;
+    std::string *OldPtr =
+        FilesToRemoveRef.empty() ? nullptr : &FilesToRemoveRef[0];
+    FilesToRemoveRef.push_back(Filename);
+
+    // We want to call 'c_str()' on every std::string in this vector so that if
+    // the underlying implementation requires a re-allocation, it happens here
+    // rather than inside of the signal handler. If we see the vector grow, we
+    // have to call it on every entry. If it remains in place, we only need to
+    // call it on the latest one.
+    if (OldPtr == &FilesToRemoveRef[0])
+      FilesToRemoveRef.back().c_str();
+    else
+      for (unsigned i = 0, e = FilesToRemoveRef.size(); i != e; ++i)
+        FilesToRemoveRef[i].c_str();
+  }
 
   RegisterHandlers();
   return false;
@@ -234,31 +249,166 @@ bool llvm::sys::RemoveFileOnSignal(StringRef Filename,
 
 // DontRemoveFileOnSignal - The public API
 void llvm::sys::DontRemoveFileOnSignal(StringRef Filename) {
-  SignalsMutex.acquire();
+  sys::SmartScopedLock<true> Guard(*SignalsMutex);
   std::vector<std::string>::reverse_iterator RI =
-    std::find(FilesToRemove.rbegin(), FilesToRemove.rend(), Filename);
-  std::vector<std::string>::iterator I = FilesToRemove.end();
-  if (RI != FilesToRemove.rend())
-    I = FilesToRemove.erase(RI.base()-1);
+    std::find(FilesToRemove->rbegin(), FilesToRemove->rend(), Filename);
+  std::vector<std::string>::iterator I = FilesToRemove->end();
+  if (RI != FilesToRemove->rend())
+    I = FilesToRemove->erase(RI.base()-1);
 
   // We need to call c_str() on every element which would have been moved by
   // the erase. These elements, in a C++98 implementation where c_str()
   // requires a reallocation on the first call may have had the call to c_str()
   // made on insertion become invalid by being copied down an element.
-  for (std::vector<std::string>::iterator E = FilesToRemove.end(); I != E; ++I)
+  for (std::vector<std::string>::iterator E = FilesToRemove->end(); I != E; ++I)
     I->c_str();
-
-  SignalsMutex.release();
 }
 
 /// AddSignalHandler - Add a function to be called when a signal is delivered
 /// to the process.  The handler can have a cookie passed to it to identify
 /// what instance of the handler it is.
 void llvm::sys::AddSignalHandler(void (*FnPtr)(void *), void *Cookie) {
-  CallBacksToRun.push_back(std::make_pair(FnPtr, Cookie));
+  CallBacksToRun->push_back(std::make_pair(FnPtr, Cookie));
   RegisterHandlers();
 }
 
+#if defined(HAVE_BACKTRACE) && defined(ENABLE_BACKTRACES)
+
+#if HAVE_LINK_H && (defined(__linux__) || defined(__FreeBSD__) ||              \
+                    defined(__FreeBSD_kernel__) || defined(__NetBSD__))
+struct DlIteratePhdrData {
+  void **StackTrace;
+  int depth;
+  bool first;
+  const char **modules;
+  intptr_t *offsets;
+  const char *main_exec_name;
+};
+
+static int dl_iterate_phdr_cb(dl_phdr_info *info, size_t size, void *arg) {
+  DlIteratePhdrData *data = (DlIteratePhdrData*)arg;
+  const char *name = data->first ? data->main_exec_name : info->dlpi_name;
+  data->first = false;
+  for (int i = 0; i < info->dlpi_phnum; i++) {
+    const auto *phdr = &info->dlpi_phdr[i];
+    if (phdr->p_type != PT_LOAD)
+      continue;
+    intptr_t beg = info->dlpi_addr + phdr->p_vaddr;
+    intptr_t end = beg + phdr->p_memsz;
+    for (int j = 0; j < data->depth; j++) {
+      if (data->modules[j])
+        continue;
+      intptr_t addr = (intptr_t)data->StackTrace[j];
+      if (beg <= addr && addr < end) {
+        data->modules[j] = name;
+        data->offsets[j] = addr - info->dlpi_addr;
+      }
+    }
+  }
+  return 0;
+}
+
+static bool findModulesAndOffsets(void **StackTrace, int Depth,
+                                  const char **Modules, intptr_t *Offsets,
+                                  const char *MainExecutableName) {
+  DlIteratePhdrData data = {StackTrace, Depth,   true,
+                            Modules,    Offsets, MainExecutableName};
+  dl_iterate_phdr(dl_iterate_phdr_cb, &data);
+  return true;
+}
+#else
+static bool findModulesAndOffsets(void **StackTrace, int Depth,
+                                  const char **Modules, intptr_t *Offsets,
+                                  const char *MainExecutableName) {
+  return false;
+}
+#endif
+
+static bool printSymbolizedStackTrace(void **StackTrace, int Depth, FILE *FD) {
+  // FIXME: Subtract necessary number from StackTrace entries to turn return addresses
+  // into actual instruction addresses.
+  // Use llvm-symbolizer tool to symbolize the stack traces.
+  ErrorOr<std::string> LLVMSymbolizerPathOrErr =
+      sys::findProgramByName("llvm-symbolizer");
+  if (!LLVMSymbolizerPathOrErr)
+    return false;
+  const std::string &LLVMSymbolizerPath = *LLVMSymbolizerPathOrErr;
+  // We don't know argv0 or the address of main() at this point, but try
+  // to guess it anyway (it's possible on some platforms).
+  std::string MainExecutableName = sys::fs::getMainExecutable(nullptr, nullptr);
+  if (MainExecutableName.empty() ||
+      MainExecutableName.find("llvm-symbolizer") != std::string::npos)
+    return false;
+
+  std::vector<const char *> Modules(Depth, nullptr);
+  std::vector<intptr_t> Offsets(Depth, 0);
+  if (!findModulesAndOffsets(StackTrace, Depth, Modules.data(), Offsets.data(),
+                             MainExecutableName.c_str()))
+    return false;
+  int InputFD;
+  SmallString<32> InputFile, OutputFile;
+  sys::fs::createTemporaryFile("symbolizer-input", "", InputFD, InputFile);
+  sys::fs::createTemporaryFile("symbolizer-output", "", OutputFile);
+  FileRemover InputRemover(InputFile.c_str());
+  FileRemover OutputRemover(OutputFile.c_str());
+
+  {
+    raw_fd_ostream Input(InputFD, true);
+    for (int i = 0; i < Depth; i++) {
+      if (Modules[i])
+        Input << Modules[i] << " " << (void*)Offsets[i] << "\n";
+    }
+  }
+
+  StringRef InputFileStr(InputFile);
+  StringRef OutputFileStr(OutputFile);
+  StringRef StderrFileStr;
+  const StringRef *Redirects[] = {&InputFileStr, &OutputFileStr,
+                                  &StderrFileStr};
+  const char *Args[] = {"llvm-symbolizer", "--functions=linkage", "--inlining",
+                        "--demangle", nullptr};
+  int RunResult =
+      sys::ExecuteAndWait(LLVMSymbolizerPath, Args, nullptr, Redirects);
+  if (RunResult != 0)
+    return false;
+
+  auto OutputBuf = MemoryBuffer::getFile(OutputFile.c_str());
+  if (!OutputBuf)
+    return false;
+  StringRef Output = OutputBuf.get()->getBuffer();
+  SmallVector<StringRef, 32> Lines;
+  Output.split(Lines, "\n");
+  auto CurLine = Lines.begin();
+  int frame_no = 0;
+  for (int i = 0; i < Depth; i++) {
+    if (!Modules[i]) {
+      fprintf(FD, "#%d %p\n", frame_no++, StackTrace[i]);
+      continue;
+    }
+    // Read pairs of lines (function name and file/line info) until we
+    // encounter empty line.
+    for (;;) {
+      if (CurLine == Lines.end())
+        return false;
+      StringRef FunctionName = *CurLine++;
+      if (FunctionName.empty())
+        break;
+      fprintf(FD, "#%d %p ", frame_no++, StackTrace[i]);
+      if (!FunctionName.startswith("??"))
+        fprintf(FD, "%s ", FunctionName.str().c_str());
+      if (CurLine == Lines.end())
+        return false;
+      StringRef FileLineInfo = *CurLine++;
+      if (!FileLineInfo.startswith("??"))
+        fprintf(FD, "%s", FileLineInfo.str().c_str());
+      else
+        fprintf(FD, "(%s+%p)", Modules[i], (void *)Offsets[i]);
+      fprintf(FD, "\n");
+    }
+  }
+  return true;
+}
+#endif // defined(HAVE_BACKTRACE) && defined(ENABLE_BACKTRACES)
 
 // PrintStackTrace - In the case of a program crash or fault, print out a stack
 // trace so that the user has an indication of why and where we died.
@@ -271,6 +421,8 @@ void llvm::sys::PrintStackTrace(FILE *FD) {
   // Use backtrace() to output a backtrace on Linux systems with glibc.
   int depth = backtrace(StackTrace,
                         static_cast<int>(array_lengthof(StackTrace)));
+  if (printSymbolizedStackTrace(StackTrace, depth, FD))
+    return;
 #if HAVE_DLFCN_H && __GNUG__
   int width = 0;
   for (int i = 0; i < depth; ++i) {
diff --git a/lib/Support/Unix/TimeValue.inc b/lib/Support/Unix/TimeValue.inc
index 7d4acf7..042e0da 100644
--- a/lib/Support/Unix/TimeValue.inc
+++ b/lib/Support/Unix/TimeValue.inc
@@ -41,7 +41,7 @@ TimeValue TimeValue::now() {
     // errors concern the timezone parameter which we're passing in as 0.
     // In the unlikely case it does happen, just return MinTime, no error
     // message needed.
-    return MinTime;
+    return MinTime();
   }
 
   return TimeValue(
diff --git a/lib/Support/Unix/Unix.h b/lib/Support/Unix/Unix.h
index ba688e3..e16a226 100644
--- a/lib/Support/Unix/Unix.h
+++ b/lib/Support/Unix/Unix.h
@@ -11,8 +11,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef LLVM_SYSTEM_UNIX_UNIX_H
-#define LLVM_SYSTEM_UNIX_UNIX_H
+#ifndef LLVM_LIB_SUPPORT_UNIX_UNIX_H
+#define LLVM_LIB_SUPPORT_UNIX_UNIX_H
 
 //===----------------------------------------------------------------------===//
 //=== WARNING: Implementation here must contain only generic UNIX code that