[Valgrind-developers] memcheck --track-origins=yes vs alloca/__chkstk

[John R. <jr...@Bi...>]

Hi,

When memcheck is tracking origins (--track-origins=yes), then many of the
error reports identify alloca() on Linux or __chkstk() on Win32+wine
as the source of the uninit bits.  That's true, but it would be much more
useful if the report blamed the caller of alloca or __chkstk, because
the caller is the place where the programmer must apply the fix.
This is particularly prevalent on Win32: space for most local variables
typically is allocated by __chkstk, and not via "sub $frame_size,%esp".

What are the thoughts about implementing this desire for the error report
to identify the caller of alloca or __chkstk?  What would it take to
have a traceback longer than just one $pc, or to recognize alloca/__chkstk
and make a special case which records their caller instead?

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