[lldb] Create "task" alias for "language swift task"

[kastiglione]

Make the task subcommands to be convenient by adding an alias for language swift task.

[kastiglione]

@swift-ci test

[kastiglione]

@swift-ci test

[kastiglione]

@swift-ci test

[kastiglione]

@swift-ci test

[kastiglione]

@swift-ci test macOS

[adrian-prantl]

The alternative would be and alias swift = language swift, then you'd type swift task.
@JDevlieghere Do you have any strong opinions against this patch as is?

[JDevlieghere]

I like Adrian's suggestion. Can we implement this generically so it can go upstream and work for any language plugin?

[kastiglione]

I thought about it, and wondered whether there are people would there who have a swift alias of their own, which would conflict with a builtin swift alias. Other than that, I'm neutral.

[kastiglione]

Is there room for both? Would having all the task commands be 3 levels deep (ex swift task backtrace <addr>) instead of 2 (task backtrace <addr>) lead to people using it less?

[kastiglione]

On one hand, for people work with swift, swift task is redundant. This is relevant now.

However if/when lldb supports a task that's different from swift, then task alone becomes ambiguous. Unclear when this concern becomes relevant.

[adrian-prantl]

I like Adrian's suggestion. Can we implement this generically so it can go upstream and work for any language plugin?

Given that we only got ~3 plugins I'm not sure that is a good trade-off?

[adrian-prantl]

An even wilder suggestion would be to change the name lookup rules such that all the subcommands of language $frame.GetLanguage() automatically are made available as top-level commands.

for reference:

(lldb) help language
...
      cplusplus -- Commands for operating on the C++ language runtime.
      objc      -- Commands for operating on the Objective-C language runtime.
      swift     -- A set of commands for operating on the Swift Language
                   Runtime.
(lldb) help language cplusplus
...
      demangle -- Demangle a C++ mangled name.
(lldb) help language objc
...
      class-table    -- Commands for operating on the Objective-C class table.
      tagged-pointer -- Commands for operating on Objective-C tagged pointers.
(lldb) help language swift
...
      demangle -- Demangle a Swift mangled name
      refcount -- Inspect the reference count data for a Swift object  Expects
                  'raw' input (see 'help raw-input'.)