[lldb] Specify aguments of `image list`

[kastiglione]

Summary

Register positional argument details in CommandObjectTargetModulesList.

I recently learned that image list takes a module name, but the help info
does not indicate this. With this change, help image list will show that it
accepts zero or more module names.

This makes it easier to get info about specific modules, without having to
find/grep through the full image list.

[DavidSpickett]

Can you add a test for the help output to lldb/test/API/commands/help/TestHelp.py ? Just the one line that includes the argument list is fine.

Also I see that we don't test this part of the command at all. Not an issue for this change (I assume it is working for you right now otherwise you wouldn't be doing this) but coverage would be welcome.

[kastiglione]

add to TestHelp.py

[kastiglione]

@DavidSpickett I might do some follow up work, if so I will add coverage then.

[JDevlieghere]

LGTM

PS: Small typo in your summary: s/abot/about/.

lldb/source/Commands/CommandObjectTarget.cpp

 #include "lldb/Target/SectionLoadList.h"
 #include "lldb/Target/StackFrame.h"
 #include "lldb/Target/Thread.h"
 #include "lldb/Target/ThreadSpec.h"
 #include "lldb/Utility/Args.h"
 #include "lldb/Utility/LLDBLog.h"
 #include "lldb/Utility/State.h"
 #include "lldb/Utility/Timer.h"
+#include "lldb/lldb-enumerations.h"
 #include "lldb/lldb-private-enumerations.h"
 
 #include "llvm/ADT/ScopeExit.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/FormatAdapters.h"
 
 
 using namespace lldb;
public:
     FormatWidthCollection m_format_array;
     bool m_use_global_module_list = false;
     lldb::addr_t m_module_addr = LLDB_INVALID_ADDRESS;
   };
 
   CommandObjectTargetModulesList(CommandInterpreter &interpreter)
       : CommandObjectParsed(
             interpreter, "target modules list",
-            "List current executable and dependent shared library images.",
-            "target modules list [<cmd-options>]") {}
+            "List current executable and dependent shared library images.") {
+    CommandArgumentData module_arg{eArgTypeShlibName, eArgRepeatStar};
+    m_arguments.push_back({module_arg});
+  }
 
   ~CommandObjectTargetModulesList() override = default;
 
   Options *GetOptions() override { return &m_options; }
 
 protected:
   bool DoExecute(Args &command, CommandReturnObject &result) override {
     Target *target = GetDebugger().GetSelectedTarget().get();

lldb/test/API/commands/help/TestHelp.py

class HelpCommandTestCase(TestBase):
     @no_debug_info_test
     def test_help_image_du_line_should_work(self):
         """Command 'help image du line-table' is not ambiguous and should work."""
         # 'image' is an alias for 'target modules'.
         self.expect("help image du line", substrs=[
                     'Dump the line table for one or more compilation units'])
 
     @no_debug_info_test
+    def test_help_image_list_shows_positional_args(self):
+        """Command 'help image list' should describe positional args."""
+        # 'image' is an alias for 'target modules'.
+        self.expect("help image list", substrs=[
+                    '<shlib-name> [...]'])
+
+    @no_debug_info_test
     def test_help_target_variable_syntax(self):
         """Command 'help target variable' should display <variable-name> ..."""
         self.expect("help target variable",
                     substrs=['<variable-name> [<variable-name> [...]]'])
 
     @no_debug_info_test
     def test_help_watchpoint_and_its_args(self):
         """Command 'help watchpoint', 'help watchpt-id', and 'help watchpt-id-list' should work."""