v8/test/inspector/debugger/stepping-tail-call-expected.txt
kozyatinskiy e27d18c943 [debugger] tuned StepNext and StepOut at return position
Proposed behaviour:
- StepNext at return position go into next function call (no changes with current behavior, but implemented in v8::Debug instead of hack on inspector side);
- StepOut at return position go into next non-current function call.

We need this to have better stepping in cases with native functions, blackboxed functions and/or different embedder calls (e.g. event listeners).

New behavior could be illustrated with two examples (for more see stepping-with-natives-and-frameworks test):
- let's assume that we've blackboxed callAll function, this function just takes its arguments and call one after another:
var foo = () => 1;
callAll(foo, foo, () => 2);
If we break inside of first call of function foo. Then on..
..StepNext - we're able to reach second call of function foo,
..StepOut - we're able to reach () => 2 call.

- let's consider case with native function:
[1,2,3].map(x => x * 2)
If we break inside of first callback call, then with StepNext we can iterate through all calls of callback, with StepOut we go to next statement after .map call.

Implementation details:
- when we request break we schedule step-in function call for any step action at return position and for step-in at any position,
- when we request StepOut at return position - we mark current function as needed-to-be-ignored inside of PrepareStepIn(function) call,
- when we request StepOut at not return position - we set break at return position and ask debugger to just repeat last step action on next stepping-related break.

Design doc: https://docs.google.com/document/d/1ihXHOIhP_q-fJCA0e2EiXz_Zr3B08KMjaPifcaqZ60Q/edit

BUG=v8:6118,chromium:583193
R=dgozman@chromium.org,yangguo@chromium.org

Review-Url: https://codereview.chromium.org/2758483002
Cr-Commit-Position: refs/heads/master@{#44028}
2017-03-22 14:16:18 +00:00

178 lines
2.3 KiB
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Checks stepping over tail calls.
Running test: testStepOver
f (:2:14)
f (:3:22)
f (:3:22)
f (:3:22)
(anonymous) (:5:0)
function f(x) {
if (x == 2) #debugger;
if (x-- > 0) return f(x);
Debugger.stepOver called
f (:3:2)
f (:3:22)
f (:3:22)
f (:3:22)
(anonymous) (:5:0)
if (x == 2) debugger;
#if (x-- > 0) return f(x);
}
Debugger.stepOver called
f (:3:15)
f (:3:22)
f (:3:22)
f (:3:22)
(anonymous) (:5:0)
if (x == 2) debugger;
if (x-- > 0) #return f(x);
}
Debugger.stepOver called
f (:4:0)
f (:3:22)
f (:3:22)
f (:3:22)
(anonymous) (:5:0)
if (x-- > 0) return f(x);
#}
f(5);
Debugger.stepOver called
f (:4:0)
f (:3:22)
f (:3:22)
(anonymous) (:5:0)
if (x-- > 0) return f(x);
#}
f(5);
Debugger.stepOver called
f (:4:0)
f (:3:22)
(anonymous) (:5:0)
if (x-- > 0) return f(x);
#}
f(5);
Debugger.stepOver called
f (:4:0)
(anonymous) (:5:0)
if (x-- > 0) return f(x);
#}
f(5);
Debugger.stepOver called
(anonymous) (:5:5)
}
f(5);#
Debugger.resume called
Running test: testStepOut
f (:2:14)
f (:3:22)
f (:3:22)
f (:3:22)
(anonymous) (:5:0)
function f(x) {
if (x == 2) #debugger;
if (x-- > 0) return f(x);
Debugger.stepOut called
f (:4:0)
f (:3:22)
f (:3:22)
(anonymous) (:5:0)
if (x-- > 0) return f(x);
#}
f(5);
Debugger.stepOut called
f (:4:0)
f (:3:22)
(anonymous) (:5:0)
if (x-- > 0) return f(x);
#}
f(5);
Debugger.stepOut called
f (:4:0)
(anonymous) (:5:0)
if (x-- > 0) return f(x);
#}
f(5);
Debugger.stepOut called
(anonymous) (:5:5)
}
f(5);#
Debugger.resume called
Running test: testStepOutFromReturn
f (:2:14)
f (:3:22)
f (:3:22)
f (:3:22)
(anonymous) (:5:0)
function f(x) {
if (x == 2) #debugger;
if (x-- > 0) return f(x);
Debugger.stepOver called
f (:3:2)
f (:3:22)
f (:3:22)
f (:3:22)
(anonymous) (:5:0)
if (x == 2) debugger;
#if (x-- > 0) return f(x);
}
Debugger.stepOver called
f (:3:15)
f (:3:22)
f (:3:22)
f (:3:22)
(anonymous) (:5:0)
if (x == 2) debugger;
if (x-- > 0) #return f(x);
}
Debugger.stepOut called
f (:4:0)
f (:3:22)
f (:3:22)
(anonymous) (:5:0)
if (x-- > 0) return f(x);
#}
f(5);
Debugger.stepOut called
f (:4:0)
f (:3:22)
(anonymous) (:5:0)
if (x-- > 0) return f(x);
#}
f(5);
Debugger.stepOut called
f (:4:0)
(anonymous) (:5:0)
if (x-- > 0) return f(x);
#}
f(5);
Debugger.stepOut called
(anonymous) (:5:5)
}
f(5);#
Debugger.resume called