Refine the 'watchpoint set' command to now require either the '-v' option (for watching of a variable) or
the '-e' option (for watching of an address) to be present.

Update some existing test cases with the required option and add some more test cases.

Since the '-v' option takes <variable-name> and the '-e' option takes <expr> as the command arg,
the existing infrastructure for generating the option usage can produce confusing help message,
like:

  watchpoint set -e [-w <watch-type>] [-x <byte-size>] <variable-name | expr>
  watchpoint set -v [-w <watch-type>] [-x <byte-size>] <variable-name | expr>

The solution adopted is to provide an extra member field to the struct CommandArgumentData called
(uint32_t)arg_opt_set_association, whose purpose is to link this particular argument data with some
option set(s).  Also modify the signature of CommandObject::GetFormattedCommandArguments() to:

  GetFormattedCommandArguments (Stream &str, uint32_t opt_set_mask = LLDB_OPT_SET_ALL)

it now takes an additional opt_set_mask which can be used to generate a filtered formatted command
args for help message.

Options::GenerateOptionUsage() impl is modified to call the GetFormattedCommandArguments() appropriately.
So that the help message now looks like:

  watchpoint set -e [-w <watch-type>] [-x <byte-size>] <expr>
  watchpoint set -v [-w <watch-type>] [-x <byte-size>] <variable-name>

rdar://problem/10703256


git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@150032 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/source/Interpreter/CommandObject.cpp b/source/Interpreter/CommandObject.cpp
index 7624e86..5618b6c 100644
--- a/source/Interpreter/CommandObject.cpp
+++ b/source/Interpreter/CommandObject.cpp
@@ -535,15 +535,30 @@
     return false;
 }
 
+static CommandObject::CommandArgumentEntry
+OptSetFiltered(uint32_t opt_set_mask, CommandObject::CommandArgumentEntry &cmd_arg_entry)
+{
+    CommandObject::CommandArgumentEntry ret_val;
+    for (unsigned i = 0; i < cmd_arg_entry.size(); ++i)
+        if (opt_set_mask & cmd_arg_entry[i].arg_opt_set_association)
+            ret_val.push_back(cmd_arg_entry[i]);
+    return ret_val;
+}
+
+// Default parameter value of opt_set_mask is LLDB_OPT_SET_ALL, which means take
+// all the argument data into account.  On rare cases where some argument sticks
+// with certain option sets, this function returns the option set filtered args.
 void
-CommandObject::GetFormattedCommandArguments (Stream &str)
+CommandObject::GetFormattedCommandArguments (Stream &str, uint32_t opt_set_mask)
 {
     int num_args = m_arguments.size();
     for (int i = 0; i < num_args; ++i)
     {
         if (i > 0)
             str.Printf (" ");
-        CommandArgumentEntry arg_entry = m_arguments[i];
+        CommandArgumentEntry arg_entry =
+            opt_set_mask == LLDB_OPT_SET_ALL ? m_arguments[i]
+                                             : OptSetFiltered(opt_set_mask, m_arguments[i]);
         int num_alternatives = arg_entry.size();
 
         if ((num_alternatives == 2)