[coverage] IncBlockCounter should not be side-effect

Incrementing coverage counter was triggering EvalError for
evaluateOnCallFrame when throwOnSideEffect is true.

R=jgruber@chromium.org, sigurds@chromium.org, yangguo@chromium.org

Bug: v8:10856
Change-Id: I0552e19a3a14ff61a9cb626494fb4a21979d535e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2384011
Commit-Queue: Benjamin Coe <bencoe@google.com>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Cr-Commit-Position: refs/heads/master@{#69628}

src/debug/debug-evaluate.cc

@@ -473,6 +473,7 @@ bool BytecodeHasNoSideEffect(interpreter::Bytecode bytecode) {
     case Bytecode::kToNumeric:
     case Bytecode::kToString:
     // Misc.
+    case Bytecode::kIncBlockCounter:  // Coverage counters.
     case Bytecode::kForInEnumerate:
     case Bytecode::kForInPrepare:
     case Bytecode::kForInContinue:

test/inspector/debugger/side-effect-free-coverage-enabled-expected.txt

@@ -0,0 +1,3 @@
+Tests side-effect-free evaluation with coverage enabled
+Paused on 'debugger;'
+f() returns 1

test/inspector/debugger/side-effect-free-coverage-enabled.js

@@ -0,0 +1,43 @@
+// Copyright 2020 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+let {session, contextGroup, Protocol} = InspectorTest.start('Tests side-effect-free evaluation with coverage enabled');
+
+contextGroup.addScript(`
+function testFunction()
+{
+  var o = 0;
+  function f() { return 1; }
+  function g() { o = 2; return o; }
+  f,g;
+  debugger;
+}
+//# sourceURL=foo.js`);
+
+// Side effect free call should not result in EvalError when coverage
+// is enabled:
+Protocol.Profiler.enable()
+Protocol.Profiler.startPreciseCoverage({callCount: true, detailed: true})
+
+Protocol.Debugger.enable();
+
+Protocol.Debugger.oncePaused().then(debuggerPaused);
+
+Protocol.Runtime.evaluate({ "expression": "setTimeout(testFunction, 0)" });
+
+var topFrameId;
+
+function debuggerPaused(messageObject)
+{
+  InspectorTest.log("Paused on 'debugger;'");
+
+  topFrameId = messageObject.params.callFrames[0].callFrameId;
+  Protocol.Debugger.evaluateOnCallFrame({ callFrameId: topFrameId, expression: "f()", throwOnSideEffect: true}).then(evaluatedFirst);
+}
+
+function evaluatedFirst(response)
+{
+  InspectorTest.log("f() returns " + response.result.result.value);
+  InspectorTest.completeTest();
+}

test/inspector/inspector.status

@@ -33,6 +33,7 @@
   'debugger/eval-scopes': [PASS, FAIL],
   'debugger/scope-skip-variables-with-empty-name': [PASS, FAIL],
   'debugger/update-call-frame-scopes': [PASS, FAIL],
+  'debugger/side-effect-free-coverage-enabled': [PASS, FAIL],
   'debugger/side-effect-free-debug-evaluate': [PASS, FAIL],
   'debugger/evaluate-on-call-frame-in-module': [PASS, FAIL],
 }],  # variant != default