Estimated hours taken: 16
If we are using typeinfo liveness, then clip the instmap delta fields in
goal_infos not to the nonlocals, but to the nonlocals plus the
type info or typeclass info variables needed to describe the types of the
nonlocals (this set is now called the "typeinfo completed nonlocals").
This is necessary for the proper handling of code such as resume_typeinfos.m
in tests/debugger. This involves a call to a procedure with an existentially
typed argument, where the returned argument is processed only in ways that do
not need the typeinfo describing it. The compiler therefore considered the
typeinfo to be local to the call binding it. Its binding was therefore not
recorded in the instmap delta, which in turn meant that in the absence of a
value-giving occurrence, liveness.m considered it not to be born anywhere.
On the other hand, with typeinfo liveness, occurrences of the argument are
also considered value-using occurrences of the typeinfo, so the typeinfo
was considered to die at the last such occurrence. Therefore the typeinfo
died without being born. The current code generator is sloppy enough not
to mind this, but the upcoming eager code generator isn't.
compiler/hlds_goal.m:
Document the new semantics of instmap_deltas.
compiler/quantification.m:
compiler/mode_util.m:
compiler/modes.m:
compiler/unique_modes.m:
If typeinfo liveness is set, include the relevant typeinfo variables
in the set of variables the instmap is limited to.
compiler/modes.m:
Delete some unused predicates.
compiler/hlds_pred.m:
Centralize the code for (maybe) completing a set of vars with the set
of typeinfo vars describing their types here.
compiler/call_gen.m:
compiler/live_vars.m:
Use the central code in hlds_pred.m.
compiler/accumulator.m:
compiler/cse_detection.m:
compiler/follow_code.m:
compiler/higher_order.m:
compiler/lambda.m:
compiler/liveness.m:
compiler/magic.m:
compiler/make_hlds.m:
compiler/mode_info.m:
compiler/pd_util.m:
compiler/polymorphism.m:
compiler/simplify.m:
compiler/unify_proc.m:
compiler/unneeded_code.m:
compiler/unused_args.m:
Call quantification and/or mode_util with the right arguments.
In some cases, introduce field names, predmode declarations and/or
shorter type names to make this change easier.
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