[lldb] Fix crash on SBCommandReturnObject & assignment

I was writing an SB API client and it was crashing on:
	bool DoExecute(SBDebugger dbg, char **command, SBCommandReturnObject &result) {
	  result = subcommand(dbg, "help");

That is because SBCommandReturnObject &result gets initialized inside LLDB by:
	bool DoExecute(Args &command, CommandReturnObject &result) override {
	  // std::unique_ptr gets initialized here from `&result`!!!
	  SBCommandReturnObject sb_return(&result);
	  DoExecute(...);
	  sb_return.Release();

Differential revision: https://reviews.llvm.org/D67589

llvm-svn: 373775

3 files changed, 69 insertions, 0 deletions

diff --git a/lldb/packages/Python/lldbsuite/test/api/command-return-object/Makefile b/lldb/packages/Python/lldbsuite/test/api/command-return-object/Makefile
new file mode 100644
index 00000000000..99998b20bcb
--- /dev/null
+++ b/lldb/packages/Python/lldbsuite/test/api/command-return-object/Makefile
@@ -0,0 +1,3 @@
+CXX_SOURCES := main.cpp
+
+include Makefile.rules
diff --git a/lldb/packages/Python/lldbsuite/test/api/command-return-object/TestSBCommandReturnObject.py b/lldb/packages/Python/lldbsuite/test/api/command-return-object/TestSBCommandReturnObject.py
new file mode 100644
index 00000000000..cf7dbe58daa
--- /dev/null
+++ b/lldb/packages/Python/lldbsuite/test/api/command-return-object/TestSBCommandReturnObject.py
@@ -0,0 +1,31 @@
+"""Test the lldb public C++ api for returning SBCommandReturnObject."""
+
+from __future__ import print_function
+
+
+from lldbsuite.test.decorators import *
+from lldbsuite.test.lldbtest import *
+from lldbsuite.test import lldbutil
+
+
+class TestSBCommandReturnObject(TestBase):
+
+    mydir = TestBase.compute_mydir(__file__)
+    NO_DEBUG_INFO_TESTCASE = True
+
+    @skipIfNoSBHeaders
+    def test_sb_command_return_object(self):
+        env = {self.dylibPath: self.getLLDBLibraryEnvVal()}
+
+        self.driver_exe = self.getBuildArtifact("command-return-object")
+        self.buildDriver('main.cpp', self.driver_exe)
+        self.addTearDownHook(lambda: os.remove(self.driver_exe))
+        self.signBinary(self.driver_exe)
+
+        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/command-return-object/main.cpp b/lldb/packages/Python/lldbsuite/test/api/command-return-object/main.cpp
new file mode 100644
index 00000000000..4aeaf3fd5fd
--- /dev/null
+++ b/lldb/packages/Python/lldbsuite/test/api/command-return-object/main.cpp
@@ -0,0 +1,35 @@
+#include "lldb/API/SBCommandInterpreter.h"
+#include "lldb/API/SBCommandReturnObject.h"
+#include "lldb/API/SBDebugger.h"
+
+using namespace lldb;
+
+static SBCommandReturnObject subcommand(SBDebugger &dbg, const char *cmd) {
+  SBCommandReturnObject Result;
+  dbg.GetCommandInterpreter().HandleCommand(cmd, Result);
+  return Result;
+}
+
+class CommandCrasher : public SBCommandPluginInterface {
+public:
+  bool DoExecute(SBDebugger dbg, char **command,
+                 SBCommandReturnObject &result) {
+    // Test assignment from a different SBCommandReturnObject instance.
+    result = subcommand(dbg, "help");
+    // Test also whether self-assignment is handled correctly.
+    result = result;
+    if (!result.Succeeded())
+      return false;
+    return true;
+  }
+};
+
+int main() {
+  SBDebugger::Initialize();
+  SBDebugger dbg = SBDebugger::Create(false /*source_init_files*/);
+  SBCommandInterpreter interp = dbg.GetCommandInterpreter();
+  static CommandCrasher crasher;
+  interp.AddCommand("crasher", &crasher, nullptr /*help*/);
+  SBCommandReturnObject Result;
+  dbg.GetCommandInterpreter().HandleCommand("crasher", Result);
+}