692109 - The intended crash in nsIFrame::GetOffsetToCrossDoc won't actually crash with some compilers

Status: RESOLVED FIXED

(Core :: Layout, defect)

Description

[(no longer active)]

/Users/ehsanakhgari/moz/mozilla-central/layout/generic/nsFrame.cpp:4077:5: warning: indirection of non-volatile null pointer will be deleted, not trap
      [-Wnull-dereference]
    *(static_cast<PRInt32*>(nsnull)) = 3;
    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/Users/ehsanakhgari/moz/mozilla-central/layout/generic/nsFrame.cpp:4077:5: note: consider using __builtin_trap() or qualifying pointer with 'volatile'
1 warning generated.

While this could be fixed by making the pointer volatile, we should really use NS_RUNTIMEABORT, which gives us nice crash signatures like this: https://crash-stats.mozilla.com/report/index/0f429455-ba92-4789-aa05-7984c2111005

Comment 1

[(no longer active)]

Attachment: Patch (v1)

Comment 2

[Timothy Nikkel (:tnikkel)]

Comment on attachment 564853 [details] [diff] [review]
Patch (v1)

I've pretty much got all the information I can from crashstats with this intended crash there and I still don't know how to fix the bug. I'm not sure how to proceed in fixing the main bug, whether it is better to leave the crash in or take it out.

Either way this is good.

Comment 3

[Timothy Nikkel (:tnikkel)]

(And I haven't seen any more infinite recursion crash stacks, so we aren't missing any information that we could be getting if this was causing a problem.)

Comment 4

[Ed Morley [:emorley]]

https://hg.mozilla.org/mozilla-central/rev/a16971b9a582