[Libreoffice-commits] core.git: initialize new member variables
chris.sherlock79 at gmail.com
Tue Jan 12 03:05:57 PST 2016
Unfortunately that was the case - I definitely went down the wrong path with that merge.
I've reverted it now - the commit can be found on http://cgit.freedesktop.org/libreoffice/core/commit/?id=b4b0cc2a5eef42434444e51fda4a13fc48183aa0
I need to check that UBSan tool more regularly.
But I definitely have to put my hand up for causing these errors. Apologies for this, I will do my level best not to let this occur again.
When I'm back home I've been meaning to send a post to the list summarising how font handling works and some ideas and questions around the code.
Thanks all (especially Caolon and Stephan)!
> On 12 Jan 2016, at 7:20 PM, Stephan Bergmann <sbergman at redhat.com> wrote:
>> On 01/11/2016 06:29 PM, Caolán McNamara wrote:
>> commit c93a43c0c9113bc1c787fe6b3c5e58a8bfd80be0
>> Author: Caolán McNamara <caolanm at redhat.com>
>> Date: Mon Jan 11 17:08:39 2016 +0000
>> initialize new member variables
>> Change-Id: I3839bc134b337ccb7cfdb2ee70524e4721c8f83c
>> diff --git a/vcl/source/font/fontattributes.cxx b/vcl/source/font/fontattributes.cxx
>> index be3ab68..49060f0 100644
>> --- a/vcl/source/font/fontattributes.cxx
>> +++ b/vcl/source/font/fontattributes.cxx
>> @@ -93,7 +93,18 @@ bool FontAttributes::CompareDeviceIndependentFontAttributes(const FontAttributes
>> - : mnWidth ( 0 )
>> + : meWeight(WEIGHT_DONTKNOW)
>> + , meItalic(ITALIC_DONTKNOW)
>> + , meFamily(FAMILY_DONTKNOW)
>> + , mePitch(PITCH_DONTKNOW)
>> + , meWidthType(WIDTH_DONTKNOW)
>> + , mbSymbolFlag(false)
>> + , mnQuality(0)
>> + , mbOrientation(false)
>> + , mbDevice(false)
>> + , mbSubsettable(false)
>> + , mbEmbeddable(false)
>> + , mnWidth ( 0 )
>> , mnOrientation( 0 )
>> , mnAscent( 0 )
>> , mnDescent( 0 )
> Tools like UBSan or Valgrind's memcheck started to complain about reads of uninitialized members after a series of commits that merged font-related structs in VCL together. What looked fishy is that those members had not been default-initialized in the original structs, the number of setter calls had not changed, and yet the code started to grow uninitialized reads of the members. Without a clear understanding of what was going on, we were reluctant to blindly default-initialize those members now, as it might hide problems (at least from the eyes of UBSan and Valgrind) instead of fixing them.
> Now, as I understand, Chris is going to revert those merges, as he came to the conclusion that they went in the wrong direction after all, and I assume that will obsolete the above potentially problematic commit anyway.
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