[OSSACanOwned] Bail on escaping inner pointers.

If there is a pointer escape, we cannot safely rewrite its lifetime.

Author: nate-chandler

lib/SILOptimizer/Utils/CanonicalizeOSSALifetime.cpp

@@ -239,6 +239,13 @@ bool CanonicalizeOSSALifetime::computeCanonicalLiveness() {
         break;
       case OperandOwnership::InteriorPointer:
       case OperandOwnership::AnyInteriorPointer:
+        if (liveness->checkAndUpdateInteriorPointer(use) !=
+            AddressUseKind::NonEscaping) {
+          LLVM_DEBUG(llvm::dbgs()
+                     << "      Inner address use is escaping! Giving up\n");
+          return false;
+        }
+        break;
       case OperandOwnership::GuaranteedForwarding:
       case OperandOwnership::EndBorrow:
         // Guaranteed values are exposed by inner adjacent reborrows. If user is

test/SILOptimizer/canonicalize_ossa_lifetime_unit.sil

@@ -1,16 +1,27 @@
 // RUN: %target-sil-opt -sil-print-types -test-runner %s -o /dev/null 2>&1 | %FileCheck %s
 
+import Builtin
 import Swift
 
 class C {}
 
 enum Never {}
+
+struct Pointer {
+  var rawValue: Builtin.RawPointer
+}
+
+struct Int32 {
+  var int: Builtin.Int32
+}
 sil @run : $@convention(thin) () -> Never
 sil @getOwned : $@convention(thin) () -> @owned C
 sil @barrier : $@convention(thin) () -> ()
 sil [ossa] @getC : $@convention(thin) () -> @owned C
 sil [ossa] @borrowC : $@convention(thin) (@guaranteed C) -> ()
 sil [ossa] @takeC : $@convention(thin) (@owned C) -> ()
+sil @getPointer : $@convention(thin) () -> (@owned Pointer)
+
 struct S {}
 
 struct MoS: ~Copyable {}
@@ -963,3 +974,28 @@ entry(%c : @owned $C):
   %run = function_ref @run : $@convention(thin) () -> Never
   unreachable
 }
+
+/// If there's a pointer escape (here, mark_dependence) of the value, we can't
+/// canonicalize its lifetime.
+// CHECK-LABEL: begin running test {{.*}} on dont_canonicalize_on_pointer_escape
+// CHECK-LABEL: sil [ossa] @dont_canonicalize_on_pointer_escape : {{.*}} {
+// CHECK:         load
+// CHECK-NEXT:    destroy_value
+// CHECK-LABEL: } // end sil function 'dont_canonicalize_on_pointer_escape'
+// CHECK-LABEL: end running test {{.*}} on dont_canonicalize_on_pointer_escape
+sil [ossa] @dont_canonicalize_on_pointer_escape : $@convention(thin) () -> () {
+entry:
+  %getC = function_ref @getC : $@convention(thin) () -> (@owned C)
+  %getPointer = function_ref @getPointer : $@convention(thin) () -> (@owned Pointer)
+  %c = apply %getC() : $@convention(thin) () -> (@owned C)
+  %pointer = apply %getPointer() : $@convention(thin) () -> (@owned Pointer)
+  specify_test "canonicalize_ossa_lifetime true false true %c"
+  %rawPointer = struct_extract %pointer, #Pointer.rawValue
+  %o = pointer_to_address %rawPointer to [strict] $*Int32
+  %dependent = mark_dependence [nonescaping] %o on %c
+  %int_addr = struct_element_addr %dependent, #Int32.int
+  %int = load [trivial] %int_addr
+  destroy_value %c
+  %retval = tuple ()
+  return %retval : $()
+}