[counters] Add UseCounters for 'f() = 0' syntax

test/cctest/test-usecounters.cc

Index: test/cctest/test-usecounters.cc
diff --git a/test/cctest/test-usecounters.cc b/test/cctest/test-usecounters.cc
index 8d4628c9f70f3e912acd02a3ca495898ffeff404..32a84513a4b07fdc8bac96305a437df23b1fea60 100644
--- a/test/cctest/test-usecounters.cc
+++ b/test/cctest/test-usecounters.cc
@@ -71,3 +71,50 @@ TEST(DefineGetterSetterThrowUseCount) {
       "a.__defineSetter__('b', ()=>{});");
   CHECK_EQ(2, use_counts[v8::Isolate::kDefineGetterOrSetterWouldThrow]);
 }
+
+TEST(AssigmentExpressionLHSIsCall) {
+  v8::Isolate* isolate = CcTest::isolate();
+  v8::HandleScope scope(isolate);
+  LocalContext env;
+  int use_counts[v8::Isolate::kUseCounterFeatureCount] = {};
+  global_use_counts = use_counts;
+  CcTest::isolate()->SetUseCounterCallback(MockUseCounterCallback);
+
+  // AssignmentExpressions whose LHS is not a call do not increment counters
+  CompileRun("function f(){ a = 0; a()[b] = 0; }");
+  CHECK_EQ(0,
+           use_counts[v8::Isolate::kAssigmentExpressionLHSIsCallInNonstrict]);
+  CHECK_EQ(0, use_counts[v8::Isolate::kAssigmentExpressionLHSIsCallInStrict]);
+  CompileRun("function f(){ ++a; ++a()[b]; }");
+  CHECK_EQ(0,
+           use_counts[v8::Isolate::kAssigmentExpressionLHSIsCallInNonstrict]);
+  CHECK_EQ(0, use_counts[v8::Isolate::kAssigmentExpressionLHSIsCallInStrict]);
+  CompileRun("function f(){ 'use strict'; a = 0; a()[b] = 0; }");
+  CHECK_EQ(0,
+           use_counts[v8::Isolate::kAssigmentExpressionLHSIsCallInNonstrict]);
+  CHECK_EQ(0, use_counts[v8::Isolate::kAssigmentExpressionLHSIsCallInStrict]);
+  CompileRun("function f(){ 'use strict'; ++a; ++a()[b]; }");
+  CHECK_EQ(0,
+           use_counts[v8::Isolate::kAssigmentExpressionLHSIsCallInNonstrict]);
+  CHECK_EQ(0, use_counts[v8::Isolate::kAssigmentExpressionLHSIsCallInStrict]);
+
+  // AssignmentExpressions whose LHS is a call increment appropriate counters
+  CompileRun("function f(){ a() = 0; }");
+  CHECK_EQ(1,
+           use_counts[v8::Isolate::kAssigmentExpressionLHSIsCallInNonstrict]);
+  CHECK_EQ(0, use_counts[v8::Isolate::kAssigmentExpressionLHSIsCallInStrict]);
+  CompileRun("function f(){ 'use strict'; a() = 0; }");
+  CHECK_EQ(1,
+           use_counts[v8::Isolate::kAssigmentExpressionLHSIsCallInNonstrict]);
+  CHECK_EQ(1, use_counts[v8::Isolate::kAssigmentExpressionLHSIsCallInStrict]);
+
+  // UpdateExpressions whose LHS is a call increment appropriate counters
+  CompileRun("function f(){ ++a(); }");
+  CHECK_EQ(2,
+           use_counts[v8::Isolate::kAssigmentExpressionLHSIsCallInNonstrict]);
+  CHECK_EQ(1, use_counts[v8::Isolate::kAssigmentExpressionLHSIsCallInStrict]);
+  CompileRun("function f(){ 'use strict'; ++a(); }");
+  CHECK_EQ(2,
+           use_counts[v8::Isolate::kAssigmentExpressionLHSIsCallInNonstrict]);
+  CHECK_EQ(2, use_counts[v8::Isolate::kAssigmentExpressionLHSIsCallInStrict]);
+}