cmd/compile/internal/pgo: remove most global state
Since pgo is a new package, it is reasonably straightforward to
encapsulate its state into a non-global object that we pass around,
which will help keep it isolated.
There are no functional changes in this CL, just packaging up the
globals into a new object.
There are two major pieces of cleanup remaining:
1. reflectdata and noder have separate InlineCalls calls for method
wrappers. The Profile is not plumbed there yet, but this is not a
regression as the globals were previously set only right around the
main inlining pass in gc.Main.
2. pgo.ListOfHotCallSites is still global, as it will require more work
to clean up. It is effectively a local variable in InlinePackage,
except that it assumes that InlineCalls is immediately preceded by a
CanInline call for the same function. This is not necessarily true
due to the recursive nature of CanInline. This also means that some
InlineCalls calls may be missing the list of hot callsites right now.
For #55022.
Change-Id: Ic1fe41f73df96861c65f8bfeecff89862b367290
Reviewed-on: https://go-review.googlesource.com/c/go/+/446303 Reviewed-by: Cherry Mui <cherryyz@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Michael Pratt <mpratt@google.com>