Calling SBDebugger::CeeateTarget being called on multiple threads was crashing LLDB.

I found the race condition in:

ScriptInterpreter *CommandInterpreter::GetScriptInterpreter(bool can_create);

More than one "ScriptInterpreter *" was being returned due to the race which caused any clients with the first one to now be pointing to freed memory and we would quickly crash.

Added a test to catch this so we don't regress.

<rdar://problem/28356584> 

llvm-svn: 289169

3 files changed, 78 insertions, 0 deletions

diff --git a/lldb/packages/Python/lldbsuite/test/api/multiple-targets/Makefile b/lldb/packages/Python/lldbsuite/test/api/multiple-targets/Makefile
new file mode 100644
index 00000000000..bee559c8ecd
--- /dev/null
+++ b/lldb/packages/Python/lldbsuite/test/api/multiple-targets/Makefile
@@ -0,0 +1,8 @@
+LEVEL = ../../make
+
+MAKE_DSYM := NO
+
+ENABLE_THREADS := YES
+CXX_SOURCES := main.cpp
+
+include $(LEVEL)/Makefile.rules
diff --git a/lldb/packages/Python/lldbsuite/test/api/multiple-targets/TestMultipleTargets.py b/lldb/packages/Python/lldbsuite/test/api/multiple-targets/TestMultipleTargets.py
new file mode 100644
index 00000000000..54e7b83c680
--- /dev/null
+++ b/lldb/packages/Python/lldbsuite/test/api/multiple-targets/TestMultipleTargets.py
@@ -0,0 +1,39 @@
+"""Test the lldb public C++ api when creating multiple targets simultaneously."""
+
+from __future__ import print_function
+
+
+import os
+import re
+import subprocess
+
+import lldb
+from lldbsuite.test.decorators import *
+from lldbsuite.test.lldbtest import *
+from lldbsuite.test import lldbutil
+
+
+class TestMultipleSimultaneousDebuggers(TestBase):
+
+    mydir = TestBase.compute_mydir(__file__)
+
+    @skipIfNoSBHeaders
+    def test_multiple_debuggers(self):
+        env = {self.dylibPath: self.getLLDBLibraryEnvVal()}
+
+        self.driver_exe = os.path.join(os.getcwd(), "multi-target")
+        self.buildDriver('main.cpp', self.driver_exe)
+        self.addTearDownHook(lambda: os.remove(self.driver_exe))
+        self.signBinary(self.driver_exe)
+
+# 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
+# will recognize it as a test failure.
+
+        if self.TraceOn():
+            print("Running test %s" % self.driver_exe)
+            check_call([self.driver_exe, self.driver_exe], env=env)
+        else:
+            with open(os.devnull, 'w') as fnull:
+                check_call([self.driver_exe, self.driver_exe],
+                           env=env, stdout=fnull, stderr=fnull)
diff --git a/lldb/packages/Python/lldbsuite/test/api/multiple-targets/main.cpp b/lldb/packages/Python/lldbsuite/test/api/multiple-targets/main.cpp
new file mode 100644
index 00000000000..35fb4e0d613
--- /dev/null
+++ b/lldb/packages/Python/lldbsuite/test/api/multiple-targets/main.cpp
@@ -0,0 +1,31 @@
+#include <thread>
+
+#include "lldb/API/LLDB.h"
+#include "lldb/API/SBDebugger.h"
+#include "lldb/API/SBTarget.h"
+
+using namespace lldb;
+int main (int argc, char **argv)
+{
+  // We are expecting the program path and a path to an executable to load
+  if (argc != 2)
+    return 1;
+  const char *program_file = argv[1];
+  SBDebugger::Initialize();
+  SBDebugger debugger = SBDebugger::Create(false);
+  auto lambda = [&](){
+    SBError error;
+    SBTarget target = debugger.CreateTarget(program_file, nullptr, nullptr, 
+                                            false, error);
+  };
+
+  // Create 3 targets at the same time and make sure we don't crash.
+  std::thread thread1(lambda);
+  std::thread thread2(lambda);
+  std::thread thread3(lambda);
+  thread1.join();
+  thread2.join();
+  thread3.join();
+  SBDebugger::Terminate();
+  return 0;
+}