[dart2wasm] Check import/export pragmas in user code

Change-Id: I926d108a4571d685c67d3a174a8e506910cce8f7
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/369020
Commit-Queue: Ömer Ağacan <omersa@google.com>
Reviewed-by: Martin Kustermann <kustermann@google.com>

pkg/_fe_analyzer_shared/lib/src/messages/codes_generated.dart

@@ -17641,6 +17641,17 @@ const MessageCode messageVoidWithTypeArguments = const MessageCode(
   correctionMessage: r"""Try removing the type arguments.""",
 );
 
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Code<Null> codeWasmImportOrExportInUserCode =
+    messageWasmImportOrExportInUserCode;
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const MessageCode messageWasmImportOrExportInUserCode = const MessageCode(
+  "WasmImportOrExportInUserCode",
+  problemMessage:
+      r"""Pragmas `wasm:import` and `wasm:export` are for internal use only and cannot be used by user code.""",
+);
+
 // DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
 const Code<Null> codeWeakReferenceMismatchReturnAndArgumentTypes =
     messageWeakReferenceMismatchReturnAndArgumentTypes;

pkg/dart2wasm/lib/target.dart

@@ -3,7 +3,7 @@
 // BSD-style license that can be found in the LICENSE file.
 
 import 'package:_fe_analyzer_shared/src/messages/codes.dart'
-    show Message, LocatedMessage;
+    show Message, LocatedMessage, messageWasmImportOrExportInUserCode;
 import 'package:_js_interop_checks/js_interop_checks.dart';
 import 'package:_js_interop_checks/src/js_interop.dart' as jsInteropHelper;
 import 'package:_js_interop_checks/src/transformations/shared_interop_transformer.dart';
@@ -243,6 +243,11 @@ class WasmTarget extends Target {
       ReferenceFromIndex? referenceFromIndex,
       {void Function(String msg)? logger,
       ChangedStructureNotifier? changedStructureNotifier}) {
+    // Check `wasm:import` and `wasm:export` pragmas before FFI transforms as
+    // FFI transforms convert JS interop annotations to these pragmas.
+    _checkWasmImportExportPragmas(libraries, coreTypes,
+        diagnosticReporter as DiagnosticReporter<Message, LocatedMessage>);
+
     Set<Library> transitiveImportingJSInterop = {
       ...?jsInteropHelper.calculateTransitiveImportsOfJsInteropIfUsed(
           component, Uri.parse("package:js/js.dart")),
@@ -518,3 +523,49 @@ class WasmVerification extends Verification {
     return false;
   }
 }
+
+final _dartCoreUri = Uri.parse('dart:core');
+
+/// Check that `wasm:import` and `wasm:export` pragmas are only used in `dart:`
+/// libraries and in tests, with the exception of
+/// `reject_import_export_pragmas` test.
+void _checkWasmImportExportPragmas(List<Library> libraries, CoreTypes coreTypes,
+    DiagnosticReporter<Message, LocatedMessage> diagnosticReporter) {
+  for (Library library in libraries) {
+    final importUri = library.importUri;
+    if (importUri.isScheme('dart') ||
+        (importUri.path.contains('tests/web/wasm') &&
+            !importUri.path.contains('reject_import_export_pragmas'))) {
+      continue;
+    }
+
+    for (Member member in library.members) {
+      for (Expression annotation in member.annotations) {
+        if (annotation is! ConstantExpression) {
+          continue;
+        }
+        final annotationConstant = annotation.constant;
+        if (annotationConstant is! InstanceConstant) {
+          continue;
+        }
+        final cls = annotationConstant.classNode;
+        if (cls.name == 'pragma' &&
+            cls.enclosingLibrary.importUri == _dartCoreUri) {
+          final pragmaName = annotationConstant
+              .fieldValues[coreTypes.pragmaName.fieldReference];
+          if (pragmaName is StringConstant) {
+            if (pragmaName.value == 'wasm:import' ||
+                pragmaName.value == 'wasm:export') {
+              diagnosticReporter.report(
+                messageWasmImportOrExportInUserCode,
+                annotation.fileOffset,
+                0,
+                library.fileUri,
+              );
+            }
+          }
+        }
+      }
+    }
+  }
+}

pkg/front_end/messages.status

@@ -1115,6 +1115,8 @@ VarAsTypeName/part_wrapped_script1: Fail
 VarAsTypeName/script1: Fail # Too many problems
 VariableCouldBeNullDueToWrite/analyzerCode: Fail
 VariableCouldBeNullDueToWrite/example: Fail
+WasmImportOrExportInUserCode/analyzerCode: Fail
+WasmImportOrExportInUserCode/example: Fail
 WeakReferenceMismatchReturnAndArgumentTypes/analyzerCode: Fail
 WeakReferenceMismatchReturnAndArgumentTypes/example: Fail
 WeakReferenceNotOneArgument/analyzerCode: Fail

pkg/front_end/messages.yaml

@@ -7011,6 +7011,9 @@ ResourceIdentifiersNotStatic:
 ResourceIdentifiersMultiple:
   problemMessage: "Only one resource identifier pragma can be used at a time."
 
+WasmImportOrExportInUserCode:
+  problemMessage: "Pragmas `wasm:import` and `wasm:export` are for internal use only and cannot be used by user code."
+
 WeakReferenceNotStatic:
   problemMessage: "Weak reference pragma can be used on a static method only."
 

pkg/front_end/test/spell_checking_list_messages.txt

@@ -114,6 +114,7 @@ placing
 pointer`s
 pragma
 pragma('vm:deeply
+pragmas
 preexisting
 pubspec.yaml
 r
@@ -149,4 +150,6 @@ u
 unavailable
 unsound
 v
+wasm:export
+wasm:import
 x

tests/web/wasm/reject_import_export_pragmas_test.dart

@@ -0,0 +1,16 @@
+// Copyright (c) 2024, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// Test that importing `dart:ffi` and using `wasm:import` and export pragmas
+// are not allowed.
+
+import 'dart:ffi'; //# 01: compile-time error
+
+@pragma('wasm:export', 'f') //# 02: compile-time error
+void f() {}
+
+@pragma('wasm:import', 'g') //# 03: compile-time error
+external double g(double x);
+
+void main() {}