Bug 1368266 Comment 20 Edit History

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Original comment by
on 
It saves the PC and uses it later (when dumping profiles) to generate frame display-name info (e.g. filename:lineno info for the script):

https://searchfox.org/mozilla-central/source/js/src/jit/JSJitFrameIter.cpp#635

The relevant stack trace (from jesup):

#0  0x00007fe860f84538 in js::jit::BaselineScript::nativeCodeForPC(JSScript*, unsigned char*, js::jit::PCMappingSlotInfo*)
    (this=0x7fe7be334ee0, script=0x25d31274e5b0, pc=0x7fe7c158b765 "\231\230\200", slotInfo=0x7fe834cee010)
    at ../../../../js/src/jit/BaselineJIT.h:446
        native = 0x0
#1  0x00007fe8613360fe in js::jit::JSJitProfilingFrameIterator::fixBaselineReturnAddress() (this=0x7fe834cee2b0)
    at /home/jesup/src/mozilla/inbound/js/src/jit/JSJitFrameIter.cpp:639
        slotInfo = {
          slotInfo_ = 0 '\000'
        }
        script = 0x25d31274e5b0
        override = 0x7fe7c158b765 "\231\230\200"
        bl = 0x7fff4e59f3b0
#2  0x00007fe861335d89 in js::jit::JSJitProfilingFrameIterator::moveToNextFrame(js::jit::CommonFrameLayout*)
    (this=0x7fe834cee2b0, frame=0x7fff4e59f350) at /home/jesup/src/mozilla/inbound/js/src/jit/JSJitFrameIter.cpp:731
        stubFrame = 0x7fff4e59f390
        prevType = js::jit::FrameType::BaselineStub
#3  0x00007fe86133615d in js::jit::JSJitProfilingFrameIterator::operator++() (this=0x7fe834cee2b0)
    at /home/jesup/src/mozilla/inbound/js/src/jit/JSJitFrameIter.cpp:649
        frame = 0x7fff4e59f350
#4  0x00007fe8609827ac in JS::ProfilingFrameIterator::operator++() (this=0x7fe834cee288)
    at /home/jesup/src/mozilla/inbound/js/src/vm/Stack.cpp:1807
Revision 1 by
on 
It saves the PC and uses it later (when dumping profiles) to generate frame display-name info (e.g. filename:lineno info for the script):

https://searchfox.org/mozilla-central/source/js/src/jit/JSJitFrameIter.cpp#635

The relevant stack trace (from jesup):

```
#0  0x00007fe860f84538 in js::jit::BaselineScript::nativeCodeForPC(JSScript*, unsigned char*, js::jit::PCMappingSlotInfo*)
    (this=0x7fe7be334ee0, script=0x25d31274e5b0, pc=0x7fe7c158b765 "\231\230\200", slotInfo=0x7fe834cee010)
    at ../../../../js/src/jit/BaselineJIT.h:446
        native = 0x0
#1  0x00007fe8613360fe in js::jit::JSJitProfilingFrameIterator::fixBaselineReturnAddress() (this=0x7fe834cee2b0)
    at /home/jesup/src/mozilla/inbound/js/src/jit/JSJitFrameIter.cpp:639
        slotInfo = {
          slotInfo_ = 0 '\000'
        }
        script = 0x25d31274e5b0
        override = 0x7fe7c158b765 "\231\230\200"
        bl = 0x7fff4e59f3b0
#2  0x00007fe861335d89 in js::jit::JSJitProfilingFrameIterator::moveToNextFrame(js::jit::CommonFrameLayout*)
    (this=0x7fe834cee2b0, frame=0x7fff4e59f350) at /home/jesup/src/mozilla/inbound/js/src/jit/JSJitFrameIter.cpp:731
        stubFrame = 0x7fff4e59f390
        prevType = js::jit::FrameType::BaselineStub
#3  0x00007fe86133615d in js::jit::JSJitProfilingFrameIterator::operator++() (this=0x7fe834cee2b0)
    at /home/jesup/src/mozilla/inbound/js/src/jit/JSJitFrameIter.cpp:649
        frame = 0x7fff4e59f350
#4  0x00007fe8609827ac in JS::ProfilingFrameIterator::operator++() (this=0x7fe834cee288)
    at /home/jesup/src/mozilla/inbound/js/src/vm/Stack.cpp:1807
```

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