Index: llvm/trunk/lib/Support/Signals.cpp
===================================================================
--- llvm/trunk/lib/Support/Signals.cpp
+++ llvm/trunk/lib/Support/Signals.cpp
@@ -26,15 +26,21 @@
 #include "llvm/Support/Program.h"
 #include "llvm/Support/StringSaver.h"
 #include "llvm/Support/raw_ostream.h"
+#include "llvm/Support/Options.h"
 #include <vector>
 
-namespace llvm {
-
 //===----------------------------------------------------------------------===//
 //=== WARNING: Implementation here must contain only TRULY operating system
 //===          independent code.
 //===----------------------------------------------------------------------===//
 
+using namespace llvm;
+
+static cl::opt<bool>
+    DisableSymbolication("disable-symbolication",
+                         cl::desc("Disable symbolizing crash backtraces."),
+                         cl::init(false), cl::Hidden);
+
 static ManagedStatic<std::vector<std::pair<void (*)(void *), void *>>>
     CallBacksToRun;
 void sys::RunSignalHandlers() {
@@ -44,9 +50,6 @@
     I.first(I.second);
   CallBacksToRun->clear();
 }
-}
-
-using namespace llvm;
 
 static bool findModulesAndOffsets(void **StackTrace, int Depth,
                                   const char **Modules, intptr_t *Offsets,
@@ -70,6 +73,9 @@
 static bool printSymbolizedStackTrace(StringRef Argv0,
                                       void **StackTrace, int Depth,
                                       llvm::raw_ostream &OS) {
+  if (DisableSymbolication)
+    return false;
+
   // Don't recursively invoke the llvm-symbolizer binary.
   if (Argv0.find("llvm-symbolizer") != std::string::npos)
     return false;
Index: llvm/trunk/test/BugPoint/unsymbolized.ll
===================================================================
--- llvm/trunk/test/BugPoint/unsymbolized.ll
+++ llvm/trunk/test/BugPoint/unsymbolized.ll
@@ -0,0 +1,21 @@
+; REQUIRES: loadable_module
+; RUN: echo "import sys" > %t.py
+; RUN: echo "print('args = ' + str(sys.argv))" >> %t.py
+; RUN: echo "exit(1)" >> %t.py
+; RUN: not bugpoint -load %llvmshlibdir/BugpointPasses%shlibext %s -output-prefix %t -bugpoint-crashcalls -opt-command="%python" -opt-args %t.py | FileCheck %s
+; RUN: not --crash opt -load %llvmshlibdir/BugpointPasses%shlibext %s -bugpoint-crashcalls -disable-symbolication 2>&1 | FileCheck --check-prefix=CRASH %s
+
+; Test that bugpoint disables symbolication on the opt tool to reduce runtime overhead when opt crashes
+; CHECK: args = {{.*}}'-disable-symbolication'
+
+; Test that opt, when it crashes & is passed -disable-symbolication, doesn't symbolicate.
+; In theory this test should maybe be in test/tools/opt or
+; test/Transforms, but since there doesn't seem to be another convenient way to
+; crash opt, apart from the BugpointPasses dynamic plugin, this is the spot for
+; now.
+; CRASH-NOT: Signals.inc
+
+define void @f() {
+  call void @f()
+  ret void
+}
Index: llvm/trunk/tools/bugpoint/OptimizerDriver.cpp
===================================================================
--- llvm/trunk/tools/bugpoint/OptimizerDriver.cpp
+++ llvm/trunk/tools/bugpoint/OptimizerDriver.cpp
@@ -202,10 +202,11 @@
   } else
     Args.push_back(tool.c_str());
 
-  Args.push_back("-o");
-  Args.push_back(OutputFilename.c_str());
   for (unsigned i = 0, e = OptArgs.size(); i != e; ++i)
     Args.push_back(OptArgs[i].c_str());
+  Args.push_back("-disable-symbolication");
+  Args.push_back("-o");
+  Args.push_back(OutputFilename.c_str());
   std::vector<std::string> pass_args;
   for (unsigned i = 0, e = PluginLoader::getNumPlugins(); i != e; ++i) {
     pass_args.push_back(std::string("-load"));