Fix a race condition in FuncUnwinders where the mutex was being

acquired only after checking if the ivar shared pointer was already
filled in.  But when I assign an UnwindPlan object to the shared
pointer, I assign an empty object and then fill it in.  That leaves
a window where another thread could get the shared pointer to the
empty (but quickly being-filled-in) object and lead to a crash.

Also two changes from Greg for correctness on the TestMultipleDebuggers
test case.

<rdar://problem/30564102> 

llvm-svn: 296084

2 files changed, 6 insertions, 0 deletions

diff --git a/lldb/packages/Python/lldbsuite/test/api/multiple-debuggers/TestMultipleDebuggers.py b/lldb/packages/Python/lldbsuite/test/api/multiple-debuggers/TestMultipleDebuggers.py
index 20e41f0f412..e79c5bac7d1 100644
--- a/lldb/packages/Python/lldbsuite/test/api/multiple-debuggers/TestMultipleDebuggers.py
+++ b/lldb/packages/Python/lldbsuite/test/api/multiple-debuggers/TestMultipleDebuggers.py
@@ -6,6 +6,7 @@ from __future__ import print_function
 import os
 import re
 import subprocess
+import sys
 
 import lldb
 from lldbsuite.test.decorators import *
@@ -38,6 +39,7 @@ class TestMultipleSimultaneousDebuggers(TestBase):
         self.inferior_exe = os.path.join(os.getcwd(), "testprog")
         self.buildDriver('testprog.cpp', self.inferior_exe)
         self.addTearDownHook(lambda: os.remove(self.inferior_exe))
+        sys.exit()
 
 # check_call will raise a CalledProcessError if multi-process-driver doesn't return
 # exit code 0 to indicate success.  We can let this exception go - the test harness
diff --git a/lldb/packages/Python/lldbsuite/test/api/multiple-debuggers/multi-process-driver.cpp b/lldb/packages/Python/lldbsuite/test/api/multiple-debuggers/multi-process-driver.cpp
index 883e3b56153..15170a3e5eb 100644
--- a/lldb/packages/Python/lldbsuite/test/api/multiple-debuggers/multi-process-driver.cpp
+++ b/lldb/packages/Python/lldbsuite/test/api/multiple-debuggers/multi-process-driver.cpp
@@ -217,6 +217,10 @@ void *do_one_debugger (void *in)
 
 int main (int argc, char **argv)
 {
+#if !defined(_MSC_VER)
+  signal(SIGPIPE, SIG_IGN);
+#endif
+  
     SBDebugger::Initialize();
 
     completed_threads_array = (bool *) malloc (sizeof (bool) * NUMBER_OF_SIMULTANEOUS_DEBUG_SESSIONS);