add some helper classes for building light-weight symbolic stack traces

that get printed when a program crashes.  This is the first step of many.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@66076 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 69 insertions, 0 deletions

diff --git a/lib/Support/PrettyStackTrace.cpp b/lib/Support/PrettyStackTrace.cpp
new file mode 100644
index 0000000000..f4fb20eb0e
--- /dev/null
+++ b/lib/Support/PrettyStackTrace.cpp
@@ -0,0 +1,69 @@
+//===- PrettyStackTrace.cpp - Pretty Crash Handling -----------------------===//
+// 
+//                     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 "llvm/Support/PrettyStackTrace.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/System/Signals.h"
+using namespace llvm;
+
+// FIXME: This should be thread local when llvm supports threads.
+static const PrettyStackTraceEntry *PrettyStackTraceHead = 0;
+
+/// CrashHandler - This callback is run if a fatal signal is delivered to the
+/// process, it prints the pretty stack trace.
+static void CrashHandler(void *Cookie) {
+  // If there are pretty stack frames registered, walk and emit them.
+  raw_ostream &OS = errs();
+  OS << "Stack dump:\n";
+  
+  unsigned i = 0;
+  for (const PrettyStackTraceEntry *Entry = PrettyStackTraceHead; Entry;
+       Entry = Entry->getNextEntry(), ++i) {
+    OS << i << ".\t";
+    Entry->print(OS);
+  }
+  OS.flush();
+}
+
+static bool RegisterCrashPrinter() {
+  sys::AddSignalHandler(CrashHandler, 0);
+  return false;
+}
+
+PrettyStackTraceEntry::PrettyStackTraceEntry() {
+  // The first time this is called, we register the crash printer.
+  static bool HandlerRegistered = RegisterCrashPrinter();
+  HandlerRegistered = HandlerRegistered;
+    
+  // Link ourselves.
+  NextEntry = PrettyStackTraceHead;
+  PrettyStackTraceHead = this;
+}
+
+PrettyStackTraceEntry::~PrettyStackTraceEntry() {
+  assert(PrettyStackTraceHead == this &&
+         "Pretty stack trace entry destruction is out of order");
+  PrettyStackTraceHead = getNextEntry();
+}
+
+void PrettyStackTraceString::print(raw_ostream &OS) const {
+  OS << Str << "\n";
+}
+
+void PrettyStackTraceProgram::print(raw_ostream &OS) const {
+  // Print the argument list.
+  for (unsigned i = 0, e = ArgC; i != e; ++i)
+    OS << ArgV[i] << ' ';
+  OS << '\n';
+}
\ No newline at end of file