Merge System into Support.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120298 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 303 insertions, 0 deletions

diff --git a/lib/Support/Unix/Signals.inc b/lib/Support/Unix/Signals.inc
new file mode 100644
index 0000000..0a61759
--- /dev/null
+++ b/lib/Support/Unix/Signals.inc
@@ -0,0 +1,303 @@
+//===- Signals.cpp - Generic Unix Signals Implementation -----*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines some helpful functions for dealing with the possibility of
+// Unix signals occuring while your program is running.
+//
+//===----------------------------------------------------------------------===//
+
+#include "Unix.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/Support/Mutex.h"
+#include <vector>
+#include <algorithm>
+#if HAVE_EXECINFO_H
+# include <execinfo.h>         // For backtrace().
+#endif
+#if HAVE_SIGNAL_H
+#include <signal.h>
+#endif
+#if HAVE_SYS_STAT_H
+#include <sys/stat.h>
+#endif
+#if HAVE_DLFCN_H && __GNUG__
+#include <dlfcn.h>
+#include <cxxabi.h>
+#endif
+using namespace llvm;
+
+static RETSIGTYPE SignalHandler(int Sig);  // defined below.
+
+static SmartMutex<true> SignalsMutex;
+
+/// InterruptFunction - The function to call if ctrl-c is pressed.
+static void (*InterruptFunction)() = 0;
+
+static std::vector<sys::Path> FilesToRemove;
+static std::vector<std::pair<void(*)(void*), void*> > CallBacksToRun;
+
+// IntSigs - Signals that may interrupt the program at any time.
+static const int IntSigs[] = {
+  SIGHUP, SIGINT, SIGQUIT, SIGPIPE, SIGTERM, SIGUSR1, SIGUSR2
+};
+static const int *const IntSigsEnd =
+  IntSigs + sizeof(IntSigs) / sizeof(IntSigs[0]);
+
+// KillSigs - Signals that are synchronous with the program that will cause it
+// to die.
+static const int KillSigs[] = {
+  SIGILL, SIGTRAP, SIGABRT, SIGFPE, SIGBUS, SIGSEGV
+#ifdef SIGSYS
+  , SIGSYS
+#endif
+#ifdef SIGXCPU
+  , SIGXCPU
+#endif
+#ifdef SIGXFSZ
+  , SIGXFSZ
+#endif
+#ifdef SIGEMT
+  , SIGEMT
+#endif
+};
+static const int *const KillSigsEnd =
+  KillSigs + sizeof(KillSigs) / sizeof(KillSigs[0]);
+
+static unsigned NumRegisteredSignals = 0;
+static struct {
+  struct sigaction SA;
+  int SigNo;
+} RegisteredSignalInfo[(sizeof(IntSigs)+sizeof(KillSigs))/sizeof(KillSigs[0])];
+
+
+static void RegisterHandler(int Signal) {
+  assert(NumRegisteredSignals <
+         sizeof(RegisteredSignalInfo)/sizeof(RegisteredSignalInfo[0]) &&
+         "Out of space for signal handlers!");
+
+  struct sigaction NewHandler;
+
+  NewHandler.sa_handler = SignalHandler;
+  NewHandler.sa_flags = SA_NODEFER|SA_RESETHAND;
+  sigemptyset(&NewHandler.sa_mask);
+
+  // Install the new handler, save the old one in RegisteredSignalInfo.
+  sigaction(Signal, &NewHandler,
+            &RegisteredSignalInfo[NumRegisteredSignals].SA);
+  RegisteredSignalInfo[NumRegisteredSignals].SigNo = Signal;
+  ++NumRegisteredSignals;
+}
+
+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);
+}
+
+static void UnregisterHandlers() {
+  // Restore all of the signal handlers to how they were before we showed up.
+  for (unsigned i = 0, e = NumRegisteredSignals; i != e; ++i)
+    sigaction(RegisteredSignalInfo[i].SigNo,
+              &RegisteredSignalInfo[i].SA, 0);
+  NumRegisteredSignals = 0;
+}
+
+
+/// RemoveFilesToRemove - Process the FilesToRemove list. This function
+/// should be called with the SignalsMutex lock held.
+static void RemoveFilesToRemove() {
+  while (!FilesToRemove.empty()) {
+    FilesToRemove.back().eraseFromDisk(true);
+    FilesToRemove.pop_back();
+  }
+}
+
+// SignalHandler - The signal handler that runs.
+static RETSIGTYPE SignalHandler(int Sig) {
+  // Restore the signal behavior to default, so that the program actually
+  // crashes when we return and the signal reissues.  This also ensures that if
+  // we crash in our signal handler that the program will terminate immediately
+  // instead of recursing in the signal handler.
+  UnregisterHandlers();
+
+  // Unmask all potentially blocked kill signals.
+  sigset_t SigMask;
+  sigfillset(&SigMask);
+  sigprocmask(SIG_UNBLOCK, &SigMask, 0);
+
+  SignalsMutex.acquire();
+  RemoveFilesToRemove();
+
+  if (std::find(IntSigs, IntSigsEnd, Sig) != IntSigsEnd) {
+    if (InterruptFunction) {
+      void (*IF)() = InterruptFunction;
+      SignalsMutex.release();
+      InterruptFunction = 0;
+      IF();        // run the interrupt function.
+      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);
+}
+
+void llvm::sys::RunInterruptHandlers() {
+  SignalsMutex.acquire();
+  RemoveFilesToRemove();
+  SignalsMutex.release();
+}
+
+void llvm::sys::SetInterruptFunction(void (*IF)()) {
+  SignalsMutex.acquire();
+  InterruptFunction = IF;
+  SignalsMutex.release();
+  RegisterHandlers();
+}
+
+// RemoveFileOnSignal - The public API
+bool llvm::sys::RemoveFileOnSignal(const sys::Path &Filename,
+                                   std::string* ErrMsg) {
+  SignalsMutex.acquire();
+  FilesToRemove.push_back(Filename);
+
+  SignalsMutex.release();
+
+  RegisterHandlers();
+  return false;
+}
+
+// DontRemoveFileOnSignal - The public API
+void llvm::sys::DontRemoveFileOnSignal(const sys::Path &Filename) {
+  SignalsMutex.acquire();
+  std::vector<sys::Path>::reverse_iterator I =
+    std::find(FilesToRemove.rbegin(), FilesToRemove.rend(), Filename);
+  if (I != FilesToRemove.rend())
+    FilesToRemove.erase(I.base()-1);
+  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));
+  RegisterHandlers();
+}
+
+
+// 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.
+//
+// On glibc systems we have the 'backtrace' function, which works nicely, but
+// doesn't demangle symbols.
+static void PrintStackTrace(void *) {
+#ifdef HAVE_BACKTRACE
+  static void* StackTrace[256];
+  // Use backtrace() to output a backtrace on Linux systems with glibc.
+  int depth = backtrace(StackTrace,
+                        static_cast<int>(array_lengthof(StackTrace)));
+#if HAVE_DLFCN_H && __GNUG__
+  int width = 0;
+  for (int i = 0; i < depth; ++i) {
+    Dl_info dlinfo;
+    dladdr(StackTrace[i], &dlinfo);
+    const char* name = strrchr(dlinfo.dli_fname, '/');
+
+    int nwidth;
+    if (name == NULL) nwidth = strlen(dlinfo.dli_fname);
+    else              nwidth = strlen(name) - 1;
+
+    if (nwidth > width) width = nwidth;
+  }
+
+  for (int i = 0; i < depth; ++i) {
+    Dl_info dlinfo;
+    dladdr(StackTrace[i], &dlinfo);
+
+    fprintf(stderr, "%-2d", i);
+
+    const char* name = strrchr(dlinfo.dli_fname, '/');
+    if (name == NULL) fprintf(stderr, " %-*s", width, dlinfo.dli_fname);
+    else              fprintf(stderr, " %-*s", width, name+1);
+
+    fprintf(stderr, " %#0*lx",
+            (int)(sizeof(void*) * 2) + 2, (unsigned long)StackTrace[i]);
+
+    if (dlinfo.dli_sname != NULL) {
+      int res;
+      fputc(' ', stderr);
+      char* d = abi::__cxa_demangle(dlinfo.dli_sname, NULL, NULL, &res);
+      if (d == NULL) fputs(dlinfo.dli_sname, stderr);
+      else           fputs(d, stderr);
+      free(d);
+
+      fprintf(stderr, " + %tu",(char*)StackTrace[i]-(char*)dlinfo.dli_saddr);
+    }
+    fputc('\n', stderr);
+  }
+#else
+  backtrace_symbols_fd(StackTrace, depth, STDERR_FILENO);
+#endif
+#endif
+}
+
+/// PrintStackTraceOnErrorSignal - When an error signal (such as SIBABRT or
+/// SIGSEGV) is delivered to the process, print a stack trace and then exit.
+void llvm::sys::PrintStackTraceOnErrorSignal() {
+  AddSignalHandler(PrintStackTrace, 0);
+}
+
+
+/***/
+
+// On Darwin, raise sends a signal to the main thread instead of the current
+// thread. This has the unfortunate effect that assert() and abort() will end up
+// bypassing our crash recovery attempts. We work around this for anything in
+// the same linkage unit by just defining our own versions of the assert handler
+// and abort.
+
+#ifdef __APPLE__
+
+int raise(int sig) {
+  return pthread_kill(pthread_self(), sig);
+}
+
+void __assert_rtn(const char *func,
+                  const char *file,
+                  int line,
+                  const char *expr) {
+  if (func)
+    fprintf(stderr, "Assertion failed: (%s), function %s, file %s, line %d.\n",
+            expr, func, file, line);
+  else
+    fprintf(stderr, "Assertion failed: (%s), file %s, line %d.\n",
+            expr, file, line);
+  abort();
+}
+
+#include <signal.h>
+#include <pthread.h>
+
+void abort() {
+  raise(SIGABRT);
+  usleep(1000);
+  __builtin_trap();
+}
+
+#endif