[vm/shared/bytecode] Support use of vm:shared in bytecode/interpreter.

Fixes #62032
TEST=ci

Change-Id: I80600d81ee73b16338a337f7139bf4e898af6eca
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/466124
Reviewed-by: Alexander Markov <alexmarkov@google.com>
Commit-Queue: Alexander Aprelev <aam@google.com>

Author: aam

pkg/dart2bytecode/docs/bytecode.md

@@ -524,7 +524,7 @@ type FieldDeclaration {
                 hasGetter, hasSetter,
                 hasInitializer, hasNontrivialInitializer, hasInitializerCode,
                 hasSourcePositions, hasAnnotations, hasPragma,
-                hasCustomScript, isExtensionTypeMember);
+                hasCustomScript, isExtensionTypeMember, isShared);
   PackedObject name;
   PackedObject type;
 
@@ -680,7 +680,8 @@ type ClosureDeclaration {
 }
 
 type ClosureCode {
-  UInt flags = (hasExceptionsTable, hasSourcePositions, hasLocalVariables)
+  UInt flags = (hasExceptionsTable, hasSourcePositions, hasLocalVariables,
+                capturesOnlyFinalAndSharedVars)
 
   UInt bytecodeSizeInBytes;
   Byte[bytecodeSizeInBytes] bytecodes;

pkg/dart2bytecode/lib/bytecode_generator.dart

@@ -521,6 +521,11 @@ class BytecodeGenerator extends RecursiveVisitor {
       flags |= FieldDeclaration.hasAnnotationsFlag;
       if (annotations.hasPragma) {
         flags |= FieldDeclaration.hasPragmaFlag;
+        if (pragmaParser
+            .parsedPragmas<ParsedVmSharedPragma>(field.annotations)
+            .isNotEmpty) {
+          flags |= FieldDeclaration.isShared;
+        }
       }
     }
     ObjectHandle? script;
@@ -814,12 +819,28 @@ class BytecodeGenerator extends RecursiveVisitor {
     // because it needs to be initialized lazily.
     if (_hasNonTrivialInitializer(field)) return true;
 
+    // Avoid runtime check of field type as part of (more frequently used)
+    // non-shared fields inline getter code.
+    if (pragmaParser
+        .parsedPragmas<ParsedVmSharedPragma>(field.annotations)
+        .isNotEmpty) {
+      return true;
+    }
+
     // Static late fields with no initializer also need a getter, to check if
     // it's been initialized.
     return field.isLate && field.initializer == null;
   }
 
   bool _needsSetter(Field field) {
+    // Avoid runtime check of field type as part of (more frequently used)
+    // non-shared fields inline setter code.
+    if (pragmaParser
+        .parsedPragmas<ParsedVmSharedPragma>(field.annotations)
+        .isNotEmpty) {
+      return true;
+    }
+
     // Final fields don't have a setter, except late final fields
     // without initializer.
     if (field.isFinal) {
@@ -1650,7 +1671,7 @@ class BytecodeGenerator extends RecursiveVisitor {
     currentLoopDepth = 0;
     savedMaxSourcePositions = <int>[];
 
-    locals = new LocalVariables(node, options, staticTypeContext);
+    locals = new LocalVariables(pragmaParser, node, options, staticTypeContext);
     locals.enterScope(node);
 
     final int startPosition;
@@ -2487,10 +2508,14 @@ class BytecodeGenerator extends RecursiveVisitor {
     currentLoopDepth = savedLoopDepth;
     asyncTryBlock = savedAsyncTryBlock;
 
+    bool capturesOnlyFinalAndSharedVars =
+        locals.capturesOnlyFinalAndSharedVars;
+
     locals.leaveScope();
 
     closure.code = new ClosureCode(asm.bytecode, asm.exceptionsTable,
-        finalizeSourcePositions(), finalizeLocalVariables());
+        finalizeSourcePositions(), finalizeLocalVariables(),
+        capturesOnlyFinalAndSharedVars);
 
     _popAssemblerState();
 

pkg/dart2bytecode/lib/declarations.dart

@@ -361,6 +361,7 @@ class FieldDeclaration {
   static const hasPragmaFlag = 1 << 15;
   static const hasCustomScriptFlag = 1 << 16;
   static const isExtensionTypeMemberFlag = 1 << 17;
+  static const isShared = 1 << 18;
 
   final int flags;
   final ObjectHandle name;
@@ -491,6 +492,9 @@ class FieldDeclaration {
     if ((flags & hasInitializerFlag) != 0) {
       sb.write(', has-initializer');
     }
+    if ((flags & isShared) != 0) {
+      sb.write(', shared');
+    }
     sb.writeln();
     if ((flags & hasInitializerCodeFlag) != 0) {
       sb.write('    initializer\n$initializerCode\n');
@@ -1158,11 +1162,13 @@ class ClosureCode {
   static const hasExceptionsTableFlag = 1 << 0;
   static const hasSourcePositionsFlag = 1 << 1;
   static const hasLocalVariablesFlag = 1 << 2;
+  static const capturesOnlyFinalAndSharedVarsFlag = 1 << 3;
 
   final Uint8List bytecodes;
   final ExceptionsTable exceptionsTable;
   final SourcePositions? sourcePositions;
   final LocalVariableTable? localVariables;
+  final bool capturesOnlyFinalAndSharedVars;
 
   bool get hasExceptionsTable => exceptionsTable.blocks.isNotEmpty;
   bool get hasSourcePositions => sourcePositions?.isNotEmpty ?? false;
@@ -1171,10 +1177,11 @@ class ClosureCode {
   int get flags =>
       (hasExceptionsTable ? hasExceptionsTableFlag : 0) |
       (hasSourcePositions ? hasSourcePositionsFlag : 0) |
-      (hasLocalVariables ? hasLocalVariablesFlag : 0);
+      (hasLocalVariables ? hasLocalVariablesFlag : 0) |
+      (capturesOnlyFinalAndSharedVars ? capturesOnlyFinalAndSharedVarsFlag : 0);
 
   ClosureCode(this.bytecodes, this.exceptionsTable, this.sourcePositions,
-      this.localVariables);
+      this.localVariables, this.capturesOnlyFinalAndSharedVars);
 
   void write(BufferedWriter writer) {
     writer.writePackedUInt30(flags);
@@ -1202,8 +1209,12 @@ class ClosureCode {
     final localVariables = ((flags & hasLocalVariablesFlag) != 0)
         ? reader.readLinkOffset<LocalVariableTable>()
         : null;
+    final capturesOnlyFinalAndSharedVars =
+        (flags & capturesOnlyFinalAndSharedVarsFlag) != 0;
+
     return new ClosureCode(
-        bytecodes, exceptionsTable, sourcePositions, localVariables);
+        bytecodes, exceptionsTable, sourcePositions, localVariables,
+        capturesOnlyFinalAndSharedVars);
   }
 
   @override

pkg/dart2bytecode/lib/local_vars.dart

@@ -7,6 +7,8 @@ import 'dart:math' show min, max;
 import 'package:kernel/ast.dart';
 import 'package:kernel/type_environment.dart';
 
+import 'package:vm/transformations/pragma.dart';
+
 import 'dbc.dart';
 import 'options.dart' show BytecodeOptions;
 
@@ -157,8 +159,8 @@ class LocalVariables {
   List<VariableDeclaration> get sortedNamedParameters =>
       _currentFrame.sortedNamedParameters;
 
-  LocalVariables(Member node, this.options, this.staticTypeContext) {
-    final scopeBuilder = new _ScopeBuilder(this);
+  LocalVariables(PragmaAnnotationParser pragmaParser, Member node, this.options, this.staticTypeContext) {
+    final scopeBuilder = new _ScopeBuilder(pragmaParser, this);
     node.accept(scopeBuilder);
 
     final allocator = new _Allocator(this);
@@ -175,6 +177,9 @@ class LocalVariables {
     _currentFrameInternal = _currentScopeInternal?.frame;
   }
 
+  bool get capturesOnlyFinalAndSharedVars =>
+    _currentFrame.capturesOnlyFinalAndSharedVars;
+
   void withTemp(TreeNode node, int temp, void action()) {
     final old = _temps![node];
     assert(old == null || old.length == 1);
@@ -192,16 +197,18 @@ class VarDesc {
   final VariableDeclaration declaration;
   Scope scope;
   bool isCaptured = false;
+  bool _isShared;
   int? index;
   int? originalParamSlotIndex;
 
-  VarDesc(this.declaration, this.scope) {
+  VarDesc(this.declaration, this.scope, this._isShared) {
     scope.vars.add(this);
   }
 
   Frame get frame => scope.frame;
 
   bool get isAllocated => index != null;
+  bool get isFinalOrShared => declaration.isFinal || _isShared;
 
   void capture() {
     assert(!isAllocated);
@@ -243,6 +250,7 @@ class Frame {
   int frameSize = 0;
   List<int> temporaries = <int>[];
   int? contextLevelAtEntry;
+  bool capturesOnlyFinalAndSharedVars = true;
 
   Frame(this.function, this.parent);
 
@@ -302,7 +310,9 @@ class _ScopeBuilder extends RecursiveVisitor {
   List<TreeNode> _enclosingTryCatches = const [];
   int _loopDepth = 0;
 
-  _ScopeBuilder(this.locals);
+  final PragmaAnnotationParser _pragmaParser;
+
+  _ScopeBuilder(this._pragmaParser, this.locals);
 
   List<VariableDeclaration> _sortNamedParameters(FunctionNode function) {
     final params = function.namedParameters.toList();
@@ -462,7 +472,10 @@ class _ScopeBuilder extends RecursiveVisitor {
     if (scope == null) {
       scope = _currentScope;
     }
-    final VarDesc v = new VarDesc(variable, scope);
+    final isShared = _pragmaParser
+          .parsedPragmas<ParsedVmSharedPragma>(variable.annotations)
+          .isNotEmpty;
+    final VarDesc v = new VarDesc(variable, scope, isShared);
     assert(locals._vars[variable] == null,
         'Double declaring variable ${variable}!');
     locals._vars[variable] = v;
@@ -475,6 +488,9 @@ class _ScopeBuilder extends RecursiveVisitor {
     }
     if (v.frame != _currentFrame) {
       v.capture();
+      if (!v.isFinalOrShared) {
+        _currentFrame.capturesOnlyFinalAndSharedVars = false;
+      }
     }
   }
 

pkg/vm/lib/transformations/pragma.dart

@@ -17,6 +17,7 @@ const kVmKeepNamePragmaName = "vm:keep-name";
 const kVmPlatformConstPragmaName = "vm:platform-const";
 const kVmPlatformConstIfPragmaName = "vm:platform-const-if";
 const kVmFfiNative = "vm:ffi:native";
+const kVmSharedPragmaName = "vm:shared";
 
 // Pragmas recognized by dart2wasm
 const kWasmEntryPointPragmaName = "wasm:entry-point";
@@ -91,6 +92,10 @@ class ParsedDynModuleEntryPointPragma implements ParsedPragma {
   const ParsedDynModuleEntryPointPragma();
 }
 
+class ParsedVmSharedPragma implements ParsedPragma {
+  const ParsedVmSharedPragma();
+}
+
 abstract class PragmaAnnotationParser {
   /// May return 'null' if the annotation does not represent a recognized
   /// @pragma.
@@ -234,6 +239,8 @@ class ConstantPragmaAnnotationParser implements PragmaAnnotationParser {
         return getEntryPointTypeFromOptions(options, pragmaName);
       case kDynModuleEntryPointPragmaName:
         return const ParsedDynModuleEntryPointPragma();
+      case kVmSharedPragmaName:
+        return const ParsedVmSharedPragma();
       default:
         return null;
     }

runtime/vm/bytecode_reader.cc

@@ -21,6 +21,7 @@
 #include "vm/hash.h"
 #include "vm/hash_table.h"
 #include "vm/longjump.h"
+#include "vm/object.h"
 #include "vm/object_store.h"
 #include "vm/resolver.h"
 #include "vm/reusable_handles.h"
@@ -303,9 +304,14 @@ void BytecodeReaderHelper::ReadCode(const Function& function,
           (flags & ClosureCode::kHasSourcePositionsFlag) != 0;
       const bool has_local_variables =
           (flags & ClosureCode::kHasLocalVariablesFlag) != 0;
+      const bool does_close_over_only_final_and_shared_vars =
+          (flags & ClosureCode::kCapturesOnlyFinalAndSharedVarsFlag) != 0;
 
       // Read closure bytecode and attach to closure function.
       closure_bytecode = ReadBytecode(pool);
+
+      closure.set_does_close_over_only_final_and_shared_vars(
+          does_close_over_only_final_and_shared_vars);
       closure.AttachBytecode(closure_bytecode);
 
       ReadExceptionsTable(closure, closure_bytecode, has_exceptions_table);
@@ -1790,6 +1796,7 @@ void BytecodeReaderHelper::ReadFieldDeclarations(const Class& cls,
   const int kHasPragmaFlag = 1 << 15;
   const int kHasCustomScriptFlag = 1 << 16;
   const int kIsExtensionTypeMemberFlag = 1 << 17;
+  const int kIsSharedFlag = 1 << 18;
 
   const int num_fields = reader_.ReadListLength();
   if ((num_fields == 0) && !cls.is_enum_class()) {
@@ -1818,6 +1825,7 @@ void BytecodeReaderHelper::ReadFieldDeclarations(const Class& cls,
     const bool is_extension_type_member =
         (flags & kIsExtensionTypeMemberFlag) != 0;
     const bool has_initializer = (flags & kHasInitializerFlag) != 0;
+    const bool is_shared = (flags & kIsSharedFlag) != 0;
 
     name ^= ReadObject();
     type ^= ReadObject();
@@ -1848,6 +1856,7 @@ void BytecodeReaderHelper::ReadFieldDeclarations(const Class& cls,
     field.set_is_extension_member(is_extension_member);
     field.set_is_extension_type_member(is_extension_type_member);
     field.set_has_initializer(has_initializer);
+    field.set_is_shared(is_shared);
 
     if (!has_nontrivial_initializer) {
       value = ReadObject();
@@ -1895,15 +1904,20 @@ void BytecodeReaderHelper::ReadFieldDeclarations(const Class& cls,
       function.set_is_extension_type_member(is_extension_type_member);
       SetupFieldAccessorFunction(cls, function, type);
       if (is_static) {
-        function.AttachBytecode(Object::implicit_static_getter_bytecode());
+        if (is_shared) {
+          function.AttachBytecode(
+              Object::implicit_shared_static_getter_bytecode());
+        } else {
+          function.AttachBytecode(Object::implicit_static_getter_bytecode());
+        }
       } else {
         function.AttachBytecode(Object::implicit_getter_bytecode());
       }
       functions_->SetAt(function_index_++, function);
     }
 
     if ((flags & kHasSetterFlag) != 0) {
-      ASSERT(is_late || ((!is_static) && (!is_final)));
+      ASSERT(is_late || ((!is_static) && (!is_final)) || is_shared);
       ASSERT(!is_const);
       name ^= ReadObject();
       const auto& signature = FunctionType::Handle(Z, FunctionType::New());
@@ -1922,7 +1936,12 @@ void BytecodeReaderHelper::ReadFieldDeclarations(const Class& cls,
       function.set_is_extension_type_member(is_extension_type_member);
       SetupFieldAccessorFunction(cls, function, type);
       if (is_static) {
-        function.AttachBytecode(Object::implicit_static_setter_bytecode());
+        if (is_shared) {
+          function.AttachBytecode(
+              Object::implicit_shared_static_setter_bytecode());
+        } else {
+          function.AttachBytecode(Object::implicit_static_setter_bytecode());
+        }
       } else {
         function.AttachBytecode(Object::implicit_setter_bytecode());
       }

runtime/vm/bytecode_reader.h

@@ -308,6 +308,7 @@ class BytecodeReaderHelper : public ValueObject {
     static const int kHasExceptionsTableFlag = 1 << 0;
     static const int kHasSourcePositionsFlag = 1 << 1;
     static const int kHasLocalVariablesFlag = 1 << 2;
+    static const int kCapturesOnlyFinalAndSharedVarsFlag = 1 << 3;
   };
 
   // Parameter flags, must be in sync with ParameterFlags constants in

runtime/vm/constants_kbc.h

@@ -220,7 +220,9 @@ namespace dart {
   V(VMInternal_ImplicitGetter,                    0, ORDN, ___, ___, ___)      \
   V(VMInternal_ImplicitSetter,                    0, ORDN, ___, ___, ___)      \
   V(VMInternal_ImplicitStaticGetter,              0, ORDN, ___, ___, ___)      \
+  V(VMInternal_ImplicitSharedStaticGetter,        0, ORDN, ___, ___, ___)      \
   V(VMInternal_ImplicitStaticSetter,              0, ORDN, ___, ___, ___)      \
+  V(VMInternal_ImplicitSharedStaticSetter,        0, ORDN, ___, ___, ___)      \
   V(VMInternal_MethodExtractor,                   0, ORDN, ___, ___, ___)      \
   V(VMInternal_InvokeClosure,                     0, ORDN, ___, ___, ___)      \
   V(VMInternal_InvokeField,                       0, ORDN, ___, ___, ___)      \