The effect of passing -enable-copy-propagation is both to enable the
CopyPropagation pass to shorten object lifetimes and also to enable
lexical lifetimes to ensure that object lifetimes aren't shortened while
a variable is still in scope and used.
Add a new flag, -enable-lexical-borrow-scopes=true to override
-enable-copy-propagation's effect (setting it to ::ExperimentalLate) on
SILOptions::LexicalLifetimes that sets it to ::Early even in the face of
-enable-copy-propagation. The old flag -disable-lexical-lifetimes is
renamed to -enable-lexical-borrow-scopes=false but continues to set that
option to ::Off even when -enable-copy-propagation is passed.
Verify that lexical-lifetimes and copy-propagation interact correctly to
keep objects named by variables alive in a couple interesting cases:
unsafe pointers, synchronization point calls.
Previously, both swift-frontend and sil-opt put lexical lifetimes behind
a flag named -enable-experimental-lexical-lifetimes. That's redundant.
Here, the experimental portion of the name is dropped.
Previously, TempRValueElimination would peephole simple alloc_stacks,
even when they were lexical; here, they are left for Mem2Reg to properly
handle.
Previously, SemanticARCOpts would eliminate lexical begin_borrows,
incorrectly allowing the lifetime of the value borrowed by them to be
observably shortened. Here, those borrow scopes are not eliminated if
they are lexical.
Added an executable test that verifies that a local variable strongly
referencing a delegate object keeps that delegate alive through the call
to an object that weakly references the delegate and calls out to it.
We need to run utils/swift-darwin-postprocess.py on every executable test on Darwin platforms to work around a dyld issue. (And to ad-hoc sign executables on platforms that need it.)
Add a %target-codesign step to stress tests that are currently missing it.
Fixes a compile time problem. The single linked list of merge targets in connection graph nodes can be very large.
Update the final merge target in the map, so that it has to be traversed only once for a given SILValue.
rdar://problem/71602804
The test might want to be split in two, because it does both checks for
the output of the compilation, and the run time itself, but for now mark
it as executable, so it doesn't break the Android test suite (which
cannot execute tests).
