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
diff --git a/lib/Support/PrettyStackTrace.cpp b/lib/Support/PrettyStackTrace.cpp
new file mode 100644
index 0000000..f4fb20e
--- /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