[vm] source report marks all const field as executed

Since const evaluation has been done at the front end, skip evaluating all static const field in source report.

Bug: #38284
Change-Id: I876a173b1643d3836277ebcfc1f8546a1f4c71ef
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/117166
Commit-Queue: Zichang Guo <[email protected]>
Reviewed-by: Siva Annamalai <[email protected]>
Reviewed-by: Régis Crelier <[email protected]>

Author: zichangg

runtime/observatory/tests/service/coverage_const_field_test.dart

@@ -0,0 +1,66 @@
+// Copyright (c) 2019, 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.
+
+import 'dart:developer';
+import 'package:observatory/service_io.dart';
+import 'package:unittest/unittest.dart';
+import 'service_test_common.dart';
+import 'test_helper.dart';
+
+const int LINE = 14;
+
+class Bar {
+  static const String field = "field"; // LINE
+}
+
+void testFunction() {
+  debugger();
+}
+
+var tests = <IsolateTest>[
+  hasStoppedAtBreakpoint,
+  (Isolate isolate) async {
+    var stack = await isolate.getStack();
+
+    // Make sure we are in the right place.
+    expect(stack.type, 'Stack');
+    expect(stack['frames'].length, greaterThanOrEqualTo(1));
+    expect(stack['frames'][0].function.name, 'testFunction');
+
+    var root = isolate.rootLibrary;
+    await root.load();
+    Script script = root.scripts.first;
+    await script.load();
+
+    var params = {
+      'reports': ['Coverage'],
+      'scriptId': script.id,
+      'forceCompile': true
+    };
+    var report = await isolate.invokeRpcNoUpgrade('getSourceReport', params);
+    List<dynamic> ranges = report['ranges'];
+
+    int match = 0;
+    for (var range in ranges) {
+      for (int i in range["coverage"]["hits"]) {
+        int line = script.tokenToLine(i);
+        if (line == null) {
+          throw FormatException('token ${i} was missing source location');
+        }
+        // Check LINE.
+        if (line == LINE) {
+          match = (match | 1);
+        } else if (line == LINE - 3) {
+          // static const field LINE is defined at LINE - 3.
+          match = (match | 2);
+        }
+      }
+    }
+    // Neither LINE nor Bar.field should be added into coverage.
+    expect(match, 0);
+  },
+  resumeIsolate
+];
+
+main(args) => runIsolateTests(args, tests, testeeConcurrent: testFunction);

runtime/vm/source_report.cc

@@ -585,6 +585,13 @@ void SourceReport::VisitLibrary(JSONArray* jsarr, const Library& lib) {
     functions = cls.functions();
     for (int i = 0; i < functions.Length(); i++) {
       func ^= functions.At(i);
+      // Skip getter functions of static const field.
+      if (func.kind() == RawFunction::kImplicitStaticGetter) {
+        field ^= func.accessor_field();
+        if (field.is_const() && field.is_static()) {
+          continue;
+        }
+      }
       VisitFunction(jsarr, func);
     }