Fixed a crasher where entering 'help disasm' on the command line would crash lldb.

The reasom of the crash is because of a missing entry in the argument table corresponding to eArgTypeUnsignedInteger.
Add such entry and modify the call site of the crash to go through a fail-fast API to retrieve the argument table.

Add a regression test to TestHelp.py.

llvm-svn: 135206

lldb/source/Interpreter/CommandObject.cpp

@@ -623,8 +623,9 @@ CommandObject::LookupArgumentName (const char *arg_name)
         && arg_name[len-1] == '>')
         arg_name_str = arg_name_str.substr (1, len-2);
 
+    const ArgumentTableEntry *table = GetArgumentTable();
     for (int i = 0; i < eArgTypeLastArg; ++i)
-        if (arg_name_str.compare (g_arguments_data[i].arg_name) == 0)
+        if (arg_name_str.compare (table[i].arg_name) == 0)
             return_type = g_arguments_data[i].arg_type;
 
     return return_type;
@@ -778,6 +779,7 @@ CommandObject::g_arguments_data[] =
     { eArgTypeThreadID, "thread-id", CommandCompletions::eNoCompletion, { NULL, false }, "Thread ID number." },
     { eArgTypeThreadIndex, "thread-index", CommandCompletions::eNoCompletion, { NULL, false }, "Index into the process' list of threads." },
     { eArgTypeThreadName, "thread-name", CommandCompletions::eNoCompletion, { NULL, false }, "The thread's name." },
+    { eArgTypeUnsignedInteger, "unsigned-integer", CommandCompletions::eNoCompletion, { NULL, false }, "An unsigned integer." },
     { eArgTypeUnixSignal, "unix-signal", CommandCompletions::eNoCompletion, { NULL, false }, "A valid Unix signal name or number (e.g. SIGKILL, KILL or 9)." },
     { eArgTypeVarName, "variable-name", CommandCompletions::eNoCompletion, { NULL, false }, "The name of a variable in your program." },
     { eArgTypeValue, "value", CommandCompletions::eNoCompletion, { NULL, false }, "A value could be anything, depending on where and how it is used." },

lldb/test/help/TestHelp.py

@@ -61,6 +61,11 @@ class HelpCommandTestCase(TestBase):
         self.expect("version",
             patterns = ['LLDB-' + (version_str if version_str else '[0-9]+')])
 
+    def test_help_should_not_crash_lldb(self):
+        """Command 'help disasm' should not crash lldb."""
+        self.runCmd("help disasm", check=False)
+        self.runCmd("help unsigned-integer")
+
     def test_help_should_not_hang_emacsshell(self):
         """Command 'settings set term-width 0' should not hang the help command."""
         self.runCmd("settings set term-width 0")