ThreadLocal: Move Unix-specific code out of Support/ThreadLocal.cpp

[oota-llvm.git] / lib / Support / PrettyStackTrace.cpp

diff --git a/lib/Support/PrettyStackTrace.cpp b/lib/Support/PrettyStackTrace.cpp
index 23ee5ab105aec8316f598e42b261f2a4d4297bd2..987778a1bde66999171556f571c94c59e352dddb 100644 (file)
--- a/lib/Support/PrettyStackTrace.cpp
+++ b/lib/Support/PrettyStackTrace.cpp
@@ -13,8 +13,10 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Support/PrettyStackTrace.h"
+#include "llvm-c/Core.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/Config/config.h"     // Get autoconf configuration settings
+#include "llvm/Support/ManagedStatic.h"
 #include "llvm/Support/Signals.h"
 #include "llvm/Support/ThreadLocal.h"
 #include "llvm/Support/Watchdog.h"
@@ -26,12 +28,7 @@
 
 using namespace llvm;
 
-namespace llvm {
-  bool DisablePrettyStackTrace = false;
-}
-
-// FIXME: This should be thread local when llvm supports threads.
-static sys::ThreadLocal<const PrettyStackTraceEntry> PrettyStackTraceHead;
+static ManagedStatic<sys::ThreadLocal<const PrettyStackTraceEntry> > PrettyStackTraceHead;
 
 static unsigned PrintStack(const PrettyStackTraceEntry *Entry, raw_ostream &OS){
   unsigned NextID = 0;
@@ -49,12 +46,12 @@ static unsigned PrintStack(const PrettyStackTraceEntry *Entry, raw_ostream &OS){
 /// PrintCurStackTrace - Print the current stack trace to the specified stream.
 static void PrintCurStackTrace(raw_ostream &OS) {
   // Don't print an empty trace.
-  if (PrettyStackTraceHead.get() == 0) return;
+  if (!PrettyStackTraceHead->get()) return;
   
   // If there are pretty stack frames registered, walk and emit them.
   OS << "Stack dump:\n";
   
-  PrintStack(PrettyStackTraceHead.get(), OS);
+  PrintStack(PrettyStackTraceHead->get(), OS);
   OS.flush();
 }
 
@@ -102,26 +99,28 @@ static void CrashHandler(void *) {
 #endif
 }
 
-static bool RegisterCrashPrinter() {
-  if (!DisablePrettyStackTrace)
-    sys::AddSignalHandler(CrashHandler, 0);
-  return false;
-}
-
 PrettyStackTraceEntry::PrettyStackTraceEntry() {
-  // The first time this is called, we register the crash printer.
-  static bool HandlerRegistered = RegisterCrashPrinter();
-  (void)HandlerRegistered;
-    
   // Link ourselves.
-  NextEntry = PrettyStackTraceHead.get();
-  PrettyStackTraceHead.set(this);
+  NextEntry = PrettyStackTraceHead->get();
+  PrettyStackTraceHead->set(this);
 }
 
 PrettyStackTraceEntry::~PrettyStackTraceEntry() {
-  assert(PrettyStackTraceHead.get() == this &&
+  // Do nothing if PrettyStackTraceHead is uninitialized. This can only happen
+  // if a shutdown occurred after we created the PrettyStackTraceEntry. That
+  // does occur in the following idiom:
+  //
+  // PrettyStackTraceProgram X(...);
+  // llvm_shutdown_obj Y;
+  //
+  // Without this check, we may end up removing ourselves from the stack trace
+  // after PrettyStackTraceHead has already been destroyed.
+  if (!PrettyStackTraceHead.isConstructed())
+    return;
+  
+  assert(PrettyStackTraceHead->get() == this &&
          "Pretty stack trace entry destruction is out of order");
-  PrettyStackTraceHead.set(getNextEntry());
+  PrettyStackTraceHead->set(getNextEntry());
 }
 
 void PrettyStackTraceString::print(raw_ostream &OS) const {
@@ -135,3 +134,18 @@ void PrettyStackTraceProgram::print(raw_ostream &OS) const {
     OS << ArgV[i] << ' ';
   OS << '\n';
 }
+
+static bool RegisterCrashPrinter() {
+  sys::AddSignalHandler(CrashHandler, nullptr);
+  return false;
+}
+
+void llvm::EnablePrettyStackTrace() {
+  // The first time this is called, we register the crash printer.
+  static bool HandlerRegistered = RegisterCrashPrinter();
+  (void)HandlerRegistered;
+}
+
+void LLVMEnablePrettyStackTrace() {
+  EnablePrettyStackTrace();
+}