Before this patch every Swift function would contain a top-level
DW_TAG_lexical_scope that didn't provide any useful information, used extra
space in the debug info and prevented local variables from showing up in virtual
async backtraces.
* rename -sil-print-only-function to -sil-print-function and -sil-print-only-functions to -sil-print-functions
* to print single functions, don't require -Xllvm -sil-print-all. It's now sufficient to use e.g. -Xllvm -sil-print-function=<f>
But it's still possible to select functions with -sil-print-function(s) for other print options, -sil-print-after.
This just eliminates -enable-sil-ownership from all target-swift-frontend and
target-swift-emit-silgen RUN lines. Both of those now include
enable-sil-ownership in their expansion.
At the moment the location being reported is inside the standard
library, which is not very helpful. Instead, the location should point
at the `try!` expression in the application code.
Fixes: rdar://problem/21407683
Some of the `dealloc_stack` instructions inserted where getting
a wrong scope. This manifests when running AllocBoxToStack because
it uses StackNesting as an utility. Yet another improvement in
debug informations at `-Onone`.
Fixes SR-6738.
