[dartdevc] fix #36252, export private name symbols
This adds support to DDC's Kernel backend for instance constants
inlined across module boundaries, by saving private name symbols
so they can be referred to from outside of the current module.
Change-Id: I28d45d1844f5351f506cc7606dd1c4803037304e
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/98926
Reviewed-by: Mark Zhou <markzipan@google.com>
Commit-Queue: Jenny Messerly <jmesserly@google.com>
diff --git a/pkg/dev_compiler/lib/src/compiler/shared_compiler.dart b/pkg/dev_compiler/lib/src/compiler/shared_compiler.dart
index c72b51a..d9270a2 100644
--- a/pkg/dev_compiler/lib/src/compiler/shared_compiler.dart
+++ b/pkg/dev_compiler/lib/src/compiler/shared_compiler.dart
@@ -234,33 +234,34 @@
/// Emits a private name JS Symbol for [name] scoped to the Dart [library].
///
/// If the same name is used in multiple libraries in the same module,
- /// distinct symbols will be used, so the names cannot be referenced outside
- /// of their library.
+ /// distinct symbols will be used, so each library will have distinct private
+ /// member names, that won't collide at runtime, as required by the Dart
+ /// language spec.
@protected
JS.TemporaryId emitPrivateNameSymbol(Library library, String name) {
- // TODO(jmesserly): fix this to support referring to private symbols from
- // libraries that aren't in the current module.
- //
- // This is needed for several uses cases:
- // - const instances of classes (which directly initialize fields via an
- // object literal).
- // - noSuchMethod stubs created when an interface is implemented that had
- // private members from another library.
- // - stateful hot reload, where we need the ability to patch private
- // class members.
- //
- // See https://github.com/dart-lang/sdk/issues/36252
- return _privateNames.putIfAbsent(library, () => HashMap()).putIfAbsent(name,
- () {
- var idName = name;
- if (idName.endsWith('=')) {
- idName = idName.replaceAll('=', '_');
- }
+ /// Initializes the JS `Symbol` for the private member [name] in [library].
+ ///
+ /// If the library is in the current JS module ([_libraries] contains it),
+ /// the private name will be created and exported. The exported symbol is
+ /// used for a few things:
+ ///
+ /// - private fields of constant objects
+ /// - stateful hot reload (not yet implemented)
+ /// - correct library scope in REPL (not yet implemented)
+ ///
+ /// If the library is imported, then the existing private name will be
+ /// retrieved from it. In both cases, we use the same `dart.privateName`
+ /// runtime call.
+ JS.TemporaryId initPrivateNameSymbol() {
+ var idName = name.endsWith('=') ? name.replaceAll('=', '_') : name;
var id = JS.TemporaryId(idName);
- moduleItems.add(
- js.statement('const # = Symbol(#);', [id, js.string(name, "'")]));
+ moduleItems.add(js.statement('const # = #.privateName(#, #)',
+ [id, runtimeModule, emitLibraryName(library), js.string(name)]));
return id;
- });
+ }
+
+ var privateNames = _privateNames.putIfAbsent(library, () => HashMap());
+ return privateNames.putIfAbsent(name, initPrivateNameSymbol);
}
/// Emits an expression to set the property [nameExpr] on the class [className],
@@ -409,6 +410,23 @@
}
items.add(JS.ExportDeclaration(JS.ExportClause(exports)));
+
+ if (isBuildingSdk) {
+ // Initialize the private name function.
+ // To bootstrap the SDK, this needs to be emitted before other code.
+ var symbol = JS.TemporaryId('_privateNames');
+ items.add(js.statement('const # = Symbol("_privateNames")', symbol));
+ items.add(js.statement(r'''
+ #.privateName = function(library, name) {
+ let names = library[#];
+ if (names == null) names = library[#] = new Map();
+ let symbol = names.get(name);
+ if (symbol == null) names.set(name, symbol = Symbol(name));
+ return symbol;
+ }
+ ''', [runtimeModule, symbol, symbol]));
+ }
+
return items;
}
diff --git a/tests/corelib_2/map_test.dart b/tests/corelib_2/map_test.dart
index 5c9e9a4..88d6e92 100644
--- a/tests/corelib_2/map_test.dart
+++ b/tests/corelib_2/map_test.dart
@@ -1043,4 +1043,5 @@
checkUnmodifiable(const {1: 1});
checkUnmodifiable(Map.unmodifiable({1: 1}));
checkUnmodifiable(UnmodifiableMapView({1: 1}));
+ checkUnmodifiable(const MapView({1: 1}));
}
