X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FSupport%2FPrettyStackTrace.cpp;h=d6782a70e1a4906877151d34767e3a113b07931f;hb=34509ffd82b5929133008e234c490cee8ca5d4b9;hp=2e9634c6946652b49cd603d2248dd10943181eb5;hpb=2aefa011df74864377242e413033166a125ef793;p=oota-llvm.git

diff --git a/lib/Support/PrettyStackTrace.cpp b/lib/Support/PrettyStackTrace.cpp
index 2e9634c6946..d6782a70e1a 100644
--- a/lib/Support/PrettyStackTrace.cpp
+++ b/lib/Support/PrettyStackTrace.cpp
@@ -16,6 +16,7 @@
 #include "llvm-c/Core.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/Config/config.h"     // Get autoconf configuration settings
+#include "llvm/Support/Compiler.h"
 #include "llvm/Support/Signals.h"
 #include "llvm/Support/Watchdog.h"
 #include "llvm/Support/raw_ostream.h"
@@ -26,29 +27,15 @@
 
 using namespace llvm;
 
+// If backtrace support is not enabled, compile out support for pretty stack
+// traces.  This has the secondary effect of not requiring thread local storage
+// when backtrace support is disabled.
+#if defined(HAVE_BACKTRACE) && defined(ENABLE_BACKTRACES)
+
 // We need a thread local pointer to manage the stack of our stack trace
 // objects, but we *really* cannot tolerate destructors running and do not want
 // to pay any overhead of synchronizing. As a consequence, we use a raw
-// thread-local variable. Some day, we should be able to use a limited subset
-// of C++11's thread_local, but compilers aren't up for it today.
-// FIXME: This should be moved to a Compiler.h abstraction.
-#ifdef _MSC_VER
-// MSVC supports this with a __declspec.
-#define LLVM_THREAD_LOCAL __declspec(thread)
-#else
-// Clang, GCC, and all compatible compilers tend to use __thread. But we need
-// to work aronud a bug in the combination of Clang's compilation of
-// local-dynamic TLS and the ppc64 linker relocations which we do by forcing to
-// general-dynamic.
-// FIXME: Make this conditional on the Clang version once this is fixed in
-// top-of-tree.
-#if defined(__clang__) && defined(__powerpc64__)
-#define LLVM_THREAD_LOCAL __thread __attribute__((tls_model("general-dynamic")))
-#else
-#define LLVM_THREAD_LOCAL __thread
-#endif
-#endif
-
+// thread-local variable.
 static LLVM_THREAD_LOCAL const PrettyStackTraceEntry *PrettyStackTraceHead =
     nullptr;
 
@@ -121,16 +108,23 @@ static void CrashHandler(void *) {
 #endif
 }
 
+// defined(HAVE_BACKTRACE) && defined(ENABLE_BACKTRACES)
+#endif
+
 PrettyStackTraceEntry::PrettyStackTraceEntry() {
+#if defined(HAVE_BACKTRACE) && defined(ENABLE_BACKTRACES)
   // Link ourselves.
   NextEntry = PrettyStackTraceHead;
   PrettyStackTraceHead = this;
+#endif
 }
 
 PrettyStackTraceEntry::~PrettyStackTraceEntry() {
+#if defined(HAVE_BACKTRACE) && defined(ENABLE_BACKTRACES)
   assert(PrettyStackTraceHead == this &&
          "Pretty stack trace entry destruction is out of order");
   PrettyStackTraceHead = getNextEntry();
+#endif
 }
 
 void PrettyStackTraceString::print(raw_ostream &OS) const {
@@ -145,15 +139,33 @@ void PrettyStackTraceProgram::print(raw_ostream &OS) const {
   OS << '\n';
 }
 
+#if defined(HAVE_BACKTRACE) && defined(ENABLE_BACKTRACES)
 static bool RegisterCrashPrinter() {
   sys::AddSignalHandler(CrashHandler, nullptr);
   return false;
 }
+#endif
 
 void llvm::EnablePrettyStackTrace() {
+#if defined(HAVE_BACKTRACE) && defined(ENABLE_BACKTRACES)
   // The first time this is called, we register the crash printer.
   static bool HandlerRegistered = RegisterCrashPrinter();
   (void)HandlerRegistered;
+#endif
+}
+
+const void* llvm::SavePrettyStackState() {
+#if defined(HAVE_BACKTRACE) && defined(ENABLE_BACKTRACES)
+  return PrettyStackTraceHead;
+#else
+  return nullptr;
+#endif
+}
+
+void llvm::RestorePrettyStackState(const void* Top) {
+#if defined(HAVE_BACKTRACE) && defined(ENABLE_BACKTRACES)
+  PrettyStackTraceHead = (const PrettyStackTraceEntry*)Top;
+#endif
 }
 
 void LLVMEnablePrettyStackTrace() {