[vm/nnbd] Rename --strong-non-nullable-type-checks to --null-safety and pass it to CFE

Issue: https://github.com/dart-lang/sdk/issues/38845
Change-Id: I9baeb4a384a6b2de79df9f97e82c127ae4f611c0
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/137120
Commit-Queue: Alexander Markov <alexmarkov@google.com>
Reviewed-by: Régis Crelier <regis@google.com>
Reviewed-by: Liam Appelbe <liama@google.com>

pkg/vm/bin/kernel_service.dart

@@ -80,6 +80,7 @@ abstract class Compiler {
   final Uri platformKernelPath;
   final bool suppressWarnings;
   final bool enableAsserts;
+  final bool nullSafety;
   final List<String> experimentalFlags;
   final bool bytecode;
   final String packageConfig;
@@ -96,6 +97,7 @@ abstract class Compiler {
   Compiler(this.isolateId, this.fileSystem, this.platformKernelPath,
       {this.suppressWarnings: false,
       this.enableAsserts: false,
+      this.nullSafety: false,
       this.experimentalFlags: null,
       this.bytecode: false,
       this.supportCodeCoverage: false,
@@ -135,6 +137,7 @@ abstract class Compiler {
           onError: (msg) => errors.add(msg))
       ..environmentDefines = new EnvironmentMap()
       ..enableAsserts = enableAsserts
+      ..nnbdMode = nullSafety ? NnbdMode.Strong : NnbdMode.Weak
       ..onDiagnostic = (DiagnosticMessage message) {
         bool printMessage;
         switch (message.severity) {
@@ -281,12 +284,14 @@ class IncrementalCompilerWrapper extends Compiler {
       int isolateId, FileSystem fileSystem, Uri platformKernelPath,
       {bool suppressWarnings: false,
       bool enableAsserts: false,
+      bool nullSafety: false,
       List<String> experimentalFlags: null,
       bool bytecode: false,
       String packageConfig: null})
       : super(isolateId, fileSystem, platformKernelPath,
             suppressWarnings: suppressWarnings,
             enableAsserts: enableAsserts,
+            nullSafety: nullSafety,
             experimentalFlags: experimentalFlags,
             bytecode: bytecode,
             supportHotReload: true,
@@ -312,6 +317,7 @@ class IncrementalCompilerWrapper extends Compiler {
         isolateId, fileSystem, platformKernelPath,
         suppressWarnings: suppressWarnings,
         enableAsserts: enableAsserts,
+        nullSafety: nullSafety,
         experimentalFlags: experimentalFlags,
         bytecode: bytecode,
         packageConfig: packageConfig);
@@ -342,12 +348,14 @@ class SingleShotCompilerWrapper extends Compiler {
       {this.requireMain: false,
       bool suppressWarnings: false,
       bool enableAsserts: false,
+      bool nullSafety: false,
       List<String> experimentalFlags: null,
       bool bytecode: false,
       String packageConfig: null})
       : super(isolateId, fileSystem, platformKernelPath,
             suppressWarnings: suppressWarnings,
             enableAsserts: enableAsserts,
+            nullSafety: nullSafety,
             experimentalFlags: experimentalFlags,
             bytecode: bytecode,
             packageConfig: packageConfig);
@@ -380,6 +388,7 @@ Future<Compiler> lookupOrBuildNewIncrementalCompiler(int isolateId,
     List sourceFiles, Uri platformKernelPath, List<int> platformKernel,
     {bool suppressWarnings: false,
     bool enableAsserts: false,
+    bool nullSafety: false,
     List<String> experimentalFlags: null,
     bool bytecode: false,
     String packageConfig: null,
@@ -411,6 +420,7 @@ Future<Compiler> lookupOrBuildNewIncrementalCompiler(int isolateId,
           isolateId, fileSystem, platformKernelPath,
           suppressWarnings: suppressWarnings,
           enableAsserts: enableAsserts,
+          nullSafety: nullSafety,
           experimentalFlags: experimentalFlags,
           bytecode: bytecode,
           packageConfig: packageConfig);
@@ -613,7 +623,8 @@ Future _processLoadRequest(request) async {
   final String inputFileUri = request[2];
   final Uri script =
       inputFileUri != null ? Uri.base.resolve(inputFileUri) : null;
-  bool incremental = request[4];
+  final bool incremental = request[4];
+  final bool nullSafety = request[5];
   final int isolateId = request[6];
   final List sourceFiles = request[7];
   final bool suppressWarnings = request[8];
@@ -680,6 +691,7 @@ Future _processLoadRequest(request) async {
         isolateId, sourceFiles, platformKernelPath, platformKernel,
         suppressWarnings: suppressWarnings,
         enableAsserts: enableAsserts,
+        nullSafety: nullSafety,
         experimentalFlags: experimentalFlags,
         bytecode: bytecode,
         packageConfig: packageConfig,
@@ -693,6 +705,7 @@ Future _processLoadRequest(request) async {
         requireMain: false,
         suppressWarnings: suppressWarnings,
         enableAsserts: enableAsserts,
+        nullSafety: nullSafety,
         experimentalFlags: experimentalFlags,
         bytecode: bytecode,
         packageConfig: packageConfig);
@@ -841,7 +854,7 @@ Future trainInternal(
     scriptUri,
     platformKernelPath,
     false /* incremental */,
-    true /* strong */,
+    false /* null safety */,
     1 /* isolateId chosen randomly */,
     [] /* source files */,
     false /* suppress warnings */,

runtime/vm/compiler/backend/type_propagator.cc

@@ -826,7 +826,7 @@ bool CompileType::IsAssignableTo(NNBDMode mode, const AbstractType& other) {
   const AbstractType& compile_type = *ToAbstractType();
 
   if (compile_type.IsNullType()) {
-    if (!FLAG_strong_non_nullable_type_checks) {
+    if (!FLAG_null_safety) {
       // In weak mode, 'null' is assignable to any type.
       return true;
     }

runtime/vm/flag_list.h

@@ -189,8 +189,8 @@ constexpr bool kDartUseBackgroundCompilation = true;
   P(reorder_basic_blocks, bool, true, "Reorder basic blocks")                  \
   C(stress_async_stacks, false, false, bool, false,                            \
     "Stress test async stack traces")                                          \
-  P(strong_non_nullable_type_checks, bool, false,                              \
-    "Enable strong non-nullable type checking mode.")                          \
+  P(null_safety, bool, false,                                                  \
+    "Respect the nullability of types in casts and instance checks.")          \
   P(use_table_dispatch, bool, true, "Enable dispatch table based calls.")      \
   P(enable_isolate_groups, bool, false, "Enable isolate group support.")       \
   P(show_invisible_frames, bool, false,                                        \

runtime/vm/isolate_reload.cc

@@ -2074,7 +2074,7 @@ class FieldInvalidator {
 
   DART_FORCE_INLINE
   void CheckValueType(const Instance& value, const Field& field) {
-    if (!FLAG_strong_non_nullable_type_checks && value.IsNull()) {
+    if (!FLAG_null_safety && value.IsNull()) {
       return;
     }
     type_ = field.type();

runtime/vm/kernel_isolate.cc

@@ -613,10 +613,6 @@ class KernelCompilationRequest : public ValueObject {
     dart_incremental.type = Dart_CObject_kBool;
     dart_incremental.value.as_bool = incremental_compile;
 
-    Dart_CObject dart_strong;
-    dart_strong.type = Dart_CObject_kBool;
-    dart_strong.value.as_bool = true;
-
     // TODO(aam): Assert that isolate exists once we move CompileAndReadScript
     // compilation logic out of CreateIsolateAndSetupHelper and into
     // IsolateSetupHelper in main.cc.
@@ -644,6 +640,10 @@ class KernelCompilationRequest : public ValueObject {
     enable_asserts.value.as_bool =
         isolate != NULL ? isolate->asserts() : FLAG_enable_asserts;
 
+    Dart_CObject null_safety;
+    null_safety.type = Dart_CObject_kBool;
+    null_safety.value.as_bool = FLAG_null_safety;
+
     intptr_t num_experimental_flags = experimental_flags->length();
     Dart_CObject** experimental_flags_array =
         new Dart_CObject*[num_experimental_flags];
@@ -702,7 +702,7 @@ class KernelCompilationRequest : public ValueObject {
                                    &uri,
                                    &dart_platform_kernel,
                                    &dart_incremental,
-                                   &dart_strong,
+                                   &null_safety,
                                    &isolate_id,
                                    &files,
                                    &suppress_warnings,

runtime/vm/object.cc

@@ -17484,7 +17484,7 @@ bool Instance::IsAssignableTo(
   // In weak mode type casts, whether in legacy or opted-in libraries, the null
   // instance is detected and handled in inlined code and therefore cannot be
   // encountered here as a Dart null receiver.
-  ASSERT(FLAG_strong_non_nullable_type_checks || !IsNull());
+  ASSERT(FLAG_null_safety || !IsNull());
   // In strong mode, compute NNBD_SUBTYPE(runtimeType, other).
   // In weak mode, compute LEGACY_SUBTYPE(runtimeType, other).
   return RuntimeTypeIsSubtypeOf(mode, other, other_instantiator_type_arguments,
@@ -17543,7 +17543,7 @@ bool Instance::RuntimeTypeIsSubtypeOf(
     return true;
   }
   // In weak testing mode, Null type is a subtype of any type.
-  if (IsNull() && !FLAG_strong_non_nullable_type_checks) {
+  if (IsNull() && !FLAG_null_safety) {
     return true;
   }
   Thread* thread = Thread::Current();
@@ -17609,7 +17609,7 @@ bool Instance::RuntimeTypeIsSubtypeOf(
     return false;
   }
   if (IsNull()) {
-    ASSERT(FLAG_strong_non_nullable_type_checks);
+    ASSERT(FLAG_null_safety);
     if (instantiated_other.IsNullType()) {
       return true;
     }
@@ -18340,7 +18340,7 @@ bool AbstractType::IsSubtypeOf(NNBDMode mode,
   // Only Never? remains, which maps to Null regardless of weak/strong mode.
   if (IsNullType() || IsNeverType()) {
     // In weak mode, Null is a bottom type.
-    if (!FLAG_strong_non_nullable_type_checks) {
+    if (!FLAG_null_safety) {
       return true;
     }
     const AbstractType& unwrapped_other =
@@ -18420,8 +18420,7 @@ bool AbstractType::IsSubtypeOf(NNBDMode mode,
     }
     return false;
   }
-  if (FLAG_strong_non_nullable_type_checks && IsNullable() &&
-      other.IsNonNullable()) {
+  if (FLAG_null_safety && IsNullable() && other.IsNonNullable()) {
     return false;
   }
   return Class::IsSubtypeOf(
@@ -18789,8 +18788,7 @@ bool Type::IsEquivalent(const Instance& other,
   Nullability this_type_nullability = nullability();
   Nullability other_type_nullability = other_type.nullability();
   if (kind == TypeEquality::kInSubtypeTest) {
-    if (FLAG_strong_non_nullable_type_checks &&
-        this_type_nullability == Nullability::kNullable &&
+    if (FLAG_null_safety && this_type_nullability == Nullability::kNullable &&
         other_type_nullability == Nullability::kNonNullable) {
       return false;
     }
@@ -19509,7 +19507,7 @@ bool TypeParameter::IsEquivalent(const Instance& other,
   Nullability this_type_param_nullability = nullability();
   Nullability other_type_param_nullability = other_type_param.nullability();
   if (kind == TypeEquality::kInSubtypeTest) {
-    if (FLAG_strong_non_nullable_type_checks &&
+    if (FLAG_null_safety &&
         this_type_param_nullability == Nullability::kNullable &&
         (other_type_param_nullability == Nullability::kNonNullable ||
          other_type_param_nullability == Nullability::kUndetermined)) {

runtime/vm/object.h

@@ -892,7 +892,7 @@ enum class TypeEquality {
 // tests. The mode reflects the opted-in status of the library performing type
 // reification and/or subtype tests.
 // Note that the weak or strong testing mode is not reflected in NNBDMode, but
-// imposed globally by the value of FLAG_strong_non_nullable_type_checks.
+// imposed globally by the value of FLAG_null_safety.
 enum class NNBDMode {
   // Status of the library:
   kLegacyLib = 0,   // Library is legacy.

runtime/vm/runtime_entry.cc

@@ -821,7 +821,7 @@ DEFINE_RUNTIME_ENTRY(TypeCheck, 8) {
   ASSERT(!dst_type.IsDynamicType());  // No need to check assignment.
   // A null instance is already detected and allowed in inlined code, unless
   // strong checking is enabled.
-  ASSERT(!src_instance.IsNull() || FLAG_strong_non_nullable_type_checks);
+  ASSERT(!src_instance.IsNull() || FLAG_null_safety);
   const bool is_instance_of = src_instance.IsAssignableTo(
       nnbd_mode, dst_type, instantiator_type_arguments,
       function_type_arguments);

runtime/vm/type_testing_stubs.cc

@@ -105,17 +105,15 @@ RawCode* TypeTestingStubGenerator::DefaultCodeForType(
   }
 
   if (cid == kDynamicCid || cid == kVoidCid ||
-      (cid == kInstanceCid &&
-       (!FLAG_strong_non_nullable_type_checks || !type.IsNonNullable()))) {
+      (cid == kInstanceCid && (!FLAG_null_safety || !type.IsNonNullable()))) {
     return StubCode::TopTypeTypeTest().raw();
   }
 
   if (type.IsType() || type.IsTypeParameter()) {
     // TODO(dartbug.com/38845): Add support for specialized TTS for
     //  nullable and non-nullable types in NNBD strong mode.
-    const bool should_specialize =
-        !FLAG_precompiled_mode && lazy_specialize &&
-        (type.IsLegacy() || !FLAG_strong_non_nullable_type_checks);
+    const bool should_specialize = !FLAG_precompiled_mode && lazy_specialize &&
+                                   (type.IsLegacy() || !FLAG_null_safety);
     return should_specialize ? StubCode::LazySpecializeTypeTest().raw()
                              : StubCode::DefaultTypeTest().raw();
   }

tools/bots/test_matrix.json

@@ -717,7 +717,7 @@
           "--null-safety"
         ],
         "vm-options": [
-          "--strong-non-nullable-type-checks"
+          "--null-safety"
         ]
       }
     },
@@ -730,7 +730,7 @@
           "--null-safety"
         ],
         "vm-options": [
-          "--strong-non-nullable-type-checks"
+          "--null-safety"
         ]
       }
     },
@@ -744,7 +744,7 @@
           "--null-safety"
         ],
         "vm-options": [
-          "--strong-non-nullable-type-checks"
+          "--null-safety"
         ]
       }
     },