support calling the super version of a bound base method

[stephan]

When adapting a base method by copying its code into a callin method, any contained super call will no longer work, because it is now out off context.

Therefor it would be desirable to support a special kind of base call

base.super.m();

that has exactly the same semantics as the original super call had. Such a call would have to be bound statically to the same method that that original super call was bound to (i.e., from the bound base class's super class). Also, no callin bindings would apply to such base-super call.

Such calls should be used with care, because they kind-of break the contract of the bound base class, which normally fully hides the overridden super method. Thus, we should consider flagging this as a form of decapsulation.

[stephan]

Initial implementation in r19143 & r19144.

Regressions are fixed in r19147, r19148, r19149, r19150.

A new paragraph OTJLD §4.3(f) has been drafted in r19153.

Implementation involves two stages:

• the base call surrogate receives an additional boolean argument ('isSuperAccess') to discriminate regular base calls from base super calls.
• an access method _OT$bm$super is generated into the baseclass which only contains an invokespecial to the super method (actually a "wicked super call"). The need to create this access method is announced by a new kind in OTSpecialAccessAttribute.

Whether or not this strategy is applied during weaving depends on the compiler version by which a given class file was generated (new strategy only for version >= 1.2.4).

Not yet implemented: error reporting (e.g., base super method does not exist) and decapsulation warning.

OTJLD needs to be updated regarding: (1) a new syntax rule (2) documentation of changes between versions.

A current snapshot is uploaded to http://www.objectteams.org/distrib/otdt-updates-1.2-4.3.f. Note, that due to changes in the bytecode format, an update from older 1.2.4-snapshots to this version is not possible (code compiled by a 1.2.4 compiler is assumed to have the new format).

[stephan]

Remaining issues have been settled:

• One more bugfix in r19154
• OTJLD change recorded in r19156
• Reporting of error (r19157) and warning (r19159)

[stephan]

Just for documentation, these are the tests for the new feature:

• 4.5.13-otjld-basecall-super-access-1 - simple case
• 4.5.13-otjld-basecall-super-access-2 - base.super and normal base
• 4.5.13-otjld-basecall-super-access-3 - compatibility of old bytecode
• 4.5.13-otjld-basecall-super-access-4 - two replace bindings
• 4.5.13-otjld-basecall-super-access-5 - super method is bound, too
• 4.5.13-otjld-basecall-super-access-6 - error: no such super method