Functions "are deinit barriers" (more pedantically, applies of functions
are deinit barriers) if any of their instructions are deinit barriers.
During side-effect analysis, when walking a function's instructions for
other global effects, also check for the deinit-barrier effect. If an
instruction is found to be a deinit barrier, mark the function's global
effects accordingly.
Add SILFunction::isDeinitBarrier to conveniently access the effects
computed during ComputeSideEffects.
Update the isBarrierApply predicate to iterate over the list of callees,
if complete, to check whether any is a deinit barrier. If none is, then
the apply is not a deinit barrier.
Computes the side effects for a function, which consists of argument- and global effects.
This is similar to the ComputeEscapeEffects pass, just for side-effects.
So far, function effects only included escape effects.
This change adds side-effects (but they are not computed, yet).
It also involves refactoring of the existing escape effects.
Also the SIL effect syntax changed a bit. Details are in docs/SIL.rst
So far, argument effects were printed in square brackets before the function name, e.g.
```
sil [escapes !%0.**, !%1, %1.c*.v** => %0.v**] @foo : $@convention(thin) (@guaranteed T) -> @out S {
bb0(%0 : $*S, %1 : @guaranteed $T):
...
```
As we are adding more argument effects, this becomes unreadable.
To make it more readable, print the effects after the opening curly brace, and print a separate line for each argument. E.g.
```
sil [ossa] @foo : $@convention(thin) (@guaranteed T) -> @out S {
[%0: noescape **]
[%1: noescape, escape c*.v** => %0.v**]
bb0(%0 : $*S, %1 : @guaranteed $T):
...
```
