[IRGen] Cast fixed-size opaque globals.

In #66560 , a bug in the lowering of
`global_addr` was fixed.  Part of that fix was to postpone mapping the
type of the global into context until getting the address of the global
and projecting the buffer for the out-of-line value; at that point, the
type is mapped into context and the address is cast.

It introduced an issue for fixed-size globals, however: the type of such
globals was not mapped into context; the result was that the lowered
value set for the corresponding SIL value would have the wrong type.

Fix that by extracting the code which mapped the type into context and
cast the address to the appropriate lowered type into a lambda and call
that lambda both in both the fixed-size (newly) and non-fixed-size (as
before) cases.

rdar://114013709

Author: nate-chandler

lib/IRGen/IRGenSIL.cpp

@@ -2983,25 +2983,30 @@ void IRGenSILFunction::visitGlobalAddrInst(GlobalAddrInst *i) {
   Address addr = IGM.getAddrOfSILGlobalVariable(var, ti,
                                                 NotForDefinition);
 
+  // Get the address of the type in context.
+  auto getAddressInContext = [this, &var](auto addr) -> Address {
+    SILType loweredTyInContext =
+        var->getLoweredTypeInContext(getExpansionContext());
+    auto &tiInContext = getTypeInfo(loweredTyInContext);
+    auto ptr = Builder.CreateBitOrPointerCast(
+        addr.getAddress(), tiInContext.getStorageType()->getPointerTo());
+    addr = Address(ptr, tiInContext.getStorageType(),
+                   tiInContext.getBestKnownAlignment());
+    return addr;
+  };
+
   // If the global is fixed-size in all resilience domains that can see it,
   // we allocated storage for it statically, and there's nothing to do.
   if (ti.isFixedSize(expansion)) {
+    addr = getAddressInContext(addr);
     setLoweredAddress(i, addr);
     return;
   }
 
   // Otherwise, the static storage for the global consists of a fixed-size
   // buffer; project it.
   addr = emitProjectValueInBuffer(*this, loweredTy, addr);
-
-
-  // Get the address of the type in context.
-  SILType loweredTyInContext = var->getLoweredTypeInContext(getExpansionContext());
-  auto &tiInContext = getTypeInfo(loweredTyInContext);
-  auto ptr = Builder.CreateBitOrPointerCast(addr.getAddress(),
-                                            tiInContext.getStorageType()->getPointerTo());
-  addr = Address(ptr, tiInContext.getStorageType(),
-                 tiInContext.getBestKnownAlignment());
+  addr = getAddressInContext(addr);
   setLoweredAddress(i, addr);
 }
 

validation-test/IRGen/rdar114013709.swift

@@ -0,0 +1,7 @@
+// RUN: %target-swift-frontend -O -primary-file %s -disable-availability-checking -emit-ir | %FileCheck %s
+
+// CHECK: define{{( dllexport)?}}{{( protected)?}} i32 @main{{.*}} {
+// CHECK:      store ptr %{{[0-9]+}}, ptr @"$s13rdar1140137091xQrvp"
+actor Actor {}
+let x: some Actor = Actor()
+