EscapeInfoDumper: dump address-reachable-from-object information

Author: eeckstein

SwiftCompilerSources/Sources/Optimizer/TestPasses/EscapeInfoDumper.swift

@@ -130,11 +130,24 @@ let addressEscapeInfoDumper = FunctionPass(name: "dump-addr-escape-info", {
         let projLhs = lhs.at(AliasAnalysis.getPtrOrAddressPath(for: lhs))
         let projRhs = rhs.at(AliasAnalysis.getPtrOrAddressPath(for: rhs))
         let mayAlias = projLhs.canAddressAlias(with: projRhs, context)
-        assert(mayAlias == projRhs.canAddressAlias(with: projLhs, context),
-               "canAddressAlias(with:) must be symmetric")
+        if mayAlias != projRhs.canAddressAlias(with: projLhs, context) {
+          fatalError("canAddressAlias(with:) must be symmetric")
+        }
 
+        let addrReachable: Bool
+        if lhs.type.isAddress && !rhs.type.isAddress {
+          let anythingReachableFromRhs = rhs.at(SmallProjectionPath(.anything))
+          addrReachable = projLhs.canAddressAlias(with: anythingReachableFromRhs, context)
+          if mayAlias && !addrReachable {
+            fatalError("mayAlias implies addrReachable")
+          }
+        } else {
+          addrReachable = false
+        }
         if mayAlias {
           print("may alias")
+        } else if addrReachable {
+          print("address reachable but no alias")
         } else {
           print("no alias")
         }

test/SILOptimizer/addr_escape_info.sil

@@ -133,6 +133,44 @@ bb0:
   return %5 : $X
 }
 
+sil @return_x : $@convention(thin) (@guaranteed X) -> @owned X
+
+// CHECK-LABEL: Address escape information for test_class_argument:
+// CHECK:       pair 0 - 1
+// CHECK-NEXT:    %0 = alloc_ref $X
+// CHECK-NEXT:    %3 = ref_element_addr %2 : $X, #X.s
+// CHECK-NEXT:  may alias
+// CHECK:       End function test_class_argument
+sil @test_class_argument : $@convention(thin) () -> () {
+bb0:
+  %0 = alloc_ref $X
+  %1 = function_ref @return_x : $@convention(thin) (@guaranteed X) -> @owned X
+  %2 = apply %1(%0) : $@convention(thin) (@guaranteed X) -> @owned X
+  %3 = ref_element_addr %2 : $X, #X.s
+  fix_lifetime %0 : $X
+  fix_lifetime %3 : $*Str
+  %12 = tuple ()
+  return %12 : $()
+}
+
+// CHECK-LABEL: Address escape information for test_reachable_no_alias:
+// CHECK:       pair 0 - 1
+// CHECK-NEXT:    %3 = ref_element_addr %2 : $X, #X.s
+// CHECK-NEXT:    %0 = alloc_ref $XandIntClass
+// CHECK-NEXT:  address reachable but no alias
+// CHECK:       End function test_reachable_no_alias
+sil @test_reachable_no_alias : $@convention(thin) () -> () {
+bb0:
+  %0 = alloc_ref $XandIntClass
+  %1 = ref_element_addr %0 : $XandIntClass, #XandIntClass.x
+  %2 = load %1 : $*X
+  %3 = ref_element_addr %2 : $X, #X.s
+  fix_lifetime %3 : $*Str
+  fix_lifetime %0 : $XandIntClass
+  %12 = tuple ()
+  return %12 : $()
+}
+
 // CHECK-LABEL: Address escape information for test_struct_with_class:
 // CHECK:       value:  %1 = struct $Container (%0 : $X)
 // CHECK-NEXT:    ==>   %7 = apply %6(%1) : $@convention(thin) (@guaranteed Container) -> ()