On Monday, 6 February 2023 11:21:13 PST Lisandro Damián Nicanor Pérez Meyer wrote: > When building qtbase 6.4.2 on Debian I see: > > In member function ‘__ct ’, > inlined from ‘detached’ at > ./obj-x86_64-linux-gnu/include/QtCore/../../../src/corelib/tools/qhash.h:57 > 5:20, inlined from ‘detach’ at > ./obj-x86_64-linux-gnu/include/QtCore/../../../src/corelib/tools/qhash.h:15 > 01:75: > ./obj-x86_64-linux-gnu/include/QtCore/../../../src/corelib/tools/qhash.h:55 > 9:17: warning: argument 1 value ‘18446744073709551615’ exceeds maximum > object size 9223372036854775807 [-Walloc-size-larger-than=] > /usr/include/c++/12/new: In member function ‘detach’: > /usr/include/c++/12/new:128:26: note: in a call to allocation function > ‘operator new []’ declared here 128 | _GLIBCXX_NODISCARD void* operator > new[](std::size_t) _GLIBCXX_THROW (std::bad_alloc) > > Is this something to be worried about?
No. It's a false positive. The value that GCC is reporting is also impossible:
size_t nSpans = numBuckets >> SpanConstants::SpanShift;
spans = new Span[nSpans];
numBuckets is a size_t, so shifting it right will shift 7 (SpanShift) zeroes
in. That means the maximum value that nSpans could assume is 2^(64-7) - 1.
If you multiply that value by sizeof(Span) == 144, that would overflow the
size_t though.
--
Thiago Macieira - thiago.macieira (AT) intel.com
Cloud Software Architect - Intel DCAI Cloud Engineering
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