v8/test/mjsunit/code-coverage-precise.js

// Copyright 2017 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.

// Flags: --allow-natives-syntax --no-always-turbofan --no-stress-flush-code
// Flags: --no-stress-incremental-marking
// Files: test/mjsunit/code-coverage-utils.js

// Test precise code coverage.

// Without precise coverage enabled, we lose coverage data to the GC.
TestCoverage(
"call an IIFE",
`
(function f() {})();
`,
undefined  // The IIFE has been garbage-collected.
);

TestCoverage(
"call locally allocated function",
`
for (var i = 0; i < 10; i++) {
  let f = () => 1;
  i += f();
}
`,
undefined
);

// This does not happen with precise coverage enabled.
%DebugTogglePreciseCoverage(true);

TestCoverage(
"call an IIFE",
`
(function f() {})();
`,
[{"start":0,"end":20,"count":1},{"start":1,"end":16,"count":1}]
);

TestCoverage(
"call locally allocated function",
`
for (var i = 0; i < 10; i++) {
  let f = () => 1;
  i += f();
}
`,
[{"start":0,"end":63,"count":1},{"start":41,"end":48,"count":5}]
);

TestCoverage(
"https://crbug.com/927464",
`
!function f() {                           // 0000
  function unused() { nop(); }            // 0100
  nop();                                  // 0150
}();                                      // 0200
`,
[{"start":0,"end":199,"count":1},
 {"start":1,"end":151,"count":1},
 {"start":52,"end":80,"count":0}]
);

%DebugTogglePreciseCoverage(false);