Add AccessUseVisitor and cleanup related APIs.

Add AccesssedStorage::compute and computeInScope to mirror AccessPath.

Allow recovering the begin_access for Nested storage.

Adds AccessedStorage.visitRoots().

Author: atrick

include/swift/SIL/MemAccessUtils.h

@@ -59,7 +59,7 @@ bool pointsToLocalObject(SILValue V);
 inline bool isUniquelyIdentified(SILValue V) {
   SILValue objectRef = V;
   if (V->getType().isAddress()) {
-    auto storage = findAccessedStorage(V);
+    auto storage = AccessedStorage::compute(V);
     if (!storage)
       return false;
 

include/swift/SILOptimizer/Analysis/ValueTracking.h

@@ -4125,7 +4125,7 @@ void IRGenSILFunction::visitRefTailAddrInst(RefTailAddrInst *i) {
 }
 
 static bool isInvariantAddress(SILValue v) {
-  SILValue accessedAddress = getAccessAddress(v);
+  SILValue accessedAddress = getTypedAccessAddress(v);
   if (auto *ptrRoot = dyn_cast<PointerToAddressInst>(accessedAddress)) {
     return ptrRoot->isInvariant();
   }