On 2010-08-02-Mon 18:29, Mateusz Loskot wrote:
I compile a small test program using Visual C++ 10.0 (Visual Studio 2010 Premium) with static code analysis turned on (option /analyze):
#include <boost/array.hpp> int main() { typedef int T; // short, char, etc. boost::array<T, 2> x; T a = x[0]; }
and whichever integer type I use for T, the analyser throws similar reports every time: ... 1>g:\dev\boost\_svn\trunk\boost\array.hpp(111): warning C6385: Invalid data: accessing 'elems', the readable size is '8' bytes, but '12' bytes might be read: Lines: 110, 111
FYI, I get the very same warning on Visual Studio 2008. Interestingly, the warning doesn't appear when the array size is 1. Note also that the warning is also gone when BOOST_ASSERT call inside boost::array::operator[] is commented out: reference operator[](size_type i) { // Skipped: BOOST_ASSERT( i < N && "out of range" ); return elems[i]; }
Shall I report a ticket?
Do you have a proposed fix? I can think of a few possible options: * Add #pragma warning(disable: 6385) to boost/array.hpp * Or add an __analysis_assume call to boost::array::operator[]: reference operator[](size_type i) { BOOST_ASSERT( i < N && "out of range" ); __analysis_assume(i < N); return elems[i]; } * Or add __analysis_assume(expr) to the BOOST_ASSERT(expr) macro itself... (boost/assert.hpp)? What do you think? BTW, the following compiler bug report seems related: Microsoft Visual Studio bug report ID 281033, "False warning C6385 when a function result is used as an array index", http://connect.microsoft.com/VisualStudio/feedback/details/281033/ HTH, Niels -- Niels Dekker http://www.xs4all.nl/~nd/dekkerware Scientific programmer at LKEB, Leiden University Medical Center