On Wed, 02 May 2012 23:11:20 -0500
"David C. Rankin" <drankinatty@...> wrote:

> On 05/02/2012 09:00 PM, David C. Rankin wrote:
> > Loaded symbols for /lib/libnss_files.so.2
> > 0x00007f5859c98200 in isSpace () from /opt/tqt3/lib/libtqt-mt.so.3
> > (gdb) bt
> > #0  0x00007f5859c98200 in isSpace ()
> > from /opt/tqt3/lib/libtqt-mt.so.3 #1  0x00007f585a0a6a6c in
> > TQChar::isSpace (this=0x1c9b010) at tools/qstring.cpp:475 #2
> > 0x00007f5853f5ffc1 in KateRenderer::textWidth (this=0x1aa9210,
> > textLine=..., startcol=0, maxwidth=817, needWrap=0x7fffc9605ea8,
> > endX=0x7fffc9605e9c)
> > at /build/src/tdelibs/kate/part/katerenderer.cpp:806 #3
> > 0x00007f5853f41674 in KateViewInternal::range
> > (this=this@entry=0x1a66ce0, realLine=realLine@entry=0,
> > previous=previous@entry=0x0)
> > at /build/src/tdelibs/kate/part/kateviewinternal.cpp:1331 #4
> > 0x00007f5853f42b32 in KateViewInternal::range
> > (this=this@entry=0x1a66ce0, realLine=0, viewLine=viewLine@entry=1)
> > at /build/src/tdelibs/kate/part/kateviewinternal.cpp:1418
> 
> I guess the questions now becomes, given all of the backtraces and
> strace information we have been able to collect, where does it point
> us to begin? IIRC, Tim's bet is on tdelibs. What about Qt3? tdelibs
> more probable? Why?
> 
> As for looking at the code and looking for code that may violate a
> gcc coding standard - what would you look for?
> 
> Out of all the backtraces I've looked at, the common entry seems to
> be:
> 
> > #2  0x00007f5853f5ffc1 in KateRenderer::textWidth (this=0x1aa9210,
> > textLine=..., startcol=0, maxwidth=817, needWrap=0x7fffc9605ea8,
> > endX=0x7fffc9605e9c)
> > at /build/src/tdelibs/kate/part/katerenderer.cpp:806
> 
> Which, given the symptoms (editor OK until you paste or cursor down
> to a line that wraps), seems to point to
> tdelibs/kate/part/katerenderer.cpp:806
> 
>     if (unicode[z].isSpace())
> 
> Is there something violative of some gcc standard in the way .isSpace
> is called?	
> 
> What about the TOChar::isSpace call at tools/qstring.cpp:475?
> 
>     return ::isSpace( *this );
> 
> Same question - anything apparently wrong with this? There were a log
> of gcc47 FTBFS surrounding needing to add 'this->' to distinguish
> who's function, etcc.. what being used in the multiple declaration
> and no forward declaration error. Could one of those exist that gcc
> doesn't flag, but confuses the execution of the code of whose this is
> the right 'this' for the program to perform without crashing.
> 
> Many times looking at the code, especially where templates were used,
> gcc47 requires the explicit this-> where there are several templates
> used side by side. Those areas look like a likely place for gcc to
> get confused with which template is the 'this' template the compiler
> wants.
> 
> That's just ramblings at this point. We will actually need somebody
> to browse the files that have veen flagged in the backraces to look
> at those areas and see if anything stands out as being noncompliant.
> I could look all day at the same file and not be able to tell
> compliant/noncompliant from a hole in the ground. So I won't
> volunteer and give anyone any unjustified hope of me actually picking
> something out.
> 
> What is the best approach here?
1) This seems to be an infinite loop in katerenderer.cpp
2) The z which governs the loop isn't changed inside the loop*
so it looks like a code generation bug.
Can you do
$ gcc -S -fverbose-asm -I??? <FLAGS> katerenderer.cpp
where I??? are the include paths needed to make the file compile,
FLAGS are the CXXFLAGS you usually use to compile and then send
katerenderer.s to the list ?

*If somebody isn't convinced they can apply this patch:

diff --git a/kate/part/katerenderer.cpp b/kate/part/katerenderer.cpp
index 48b73d7..bbe5426 100644
--- a/kate/part/katerenderer.cpp
+++ b/kate/part/katerenderer.cpp
@@ -790,9 +790,10 @@ uint KateRenderer::textWidth(const KateTextLine::Ptr &textLine, uint startcol, u
   const TQChar *unicode = textLine->text();
   const TQString &textString = textLine->string();

-  uint z = startcol;
-  for (; z < len; z++)
+  uint zz = startcol;
+  for (; zz < len; zz++)
   {
+    const uint z = zz;
     KateAttribute* a = attribute(textLine->attribute(z));
     int width = a->width(*fs, textString, z, m_tabWidth);
     Q_ASSERT(width);