On Fri, Aug 22, 2014 at 12:42 PM, Chris Bieneman <be...@apple.com> wrote: > Starting a new thread to loop in cfe-dev and lldb-dev. For those not > following along there has been a thread on llvm-dev about moving the minimum > required Visual Studio version to 2013. The motivating reason is this will > allow us to take advantage of a bunch of C++11 features that are not > supported by MSVC 2012. According to MSDN > (http://msdn.microsoft.com/en-us/library/hh567368.aspx) the list is: > > * Non-static data member initializers > * Variadic templates > * Initializer lists > * Default template arguments for function templates > * Expression SFINAE > * Alias templates > * Delegating constructors > * Explicit conversion operators > * Raw string literals > * Defaulted and deleted functions > > From the discussion on LLVM-dev it is also believed that this may ease some > development pain as people keep occasionally breaking LLVM trunk by using > language features not available in MSVC. > > Original thread: > http://lists.cs.uiuc.edu/pipermail/llvmdev/2014-August/075900.html > > Chandler’s proposal for moving forward is as follows: > 1) Loop in cfe-dev and lldb-dev (Done!) > 2) Wait until this email fully circulates in digests and LLVM Weekly so that > everyone who has an objection can voice it > 3) If there are no objections, Commit a change to the CMake build which > errors on old MSVC versions > 4) Revert and fix buildbots > 5) Repeat 3 & 4 until no issues > 6) Once the change is live for a week with no issues, update the > documentation to reflect the minimum required MSVC version as 2013 > > (http://lists.cs.uiuc.edu/pipermail/llvmdev/2014-August/076090.html) > > Feedback is greatly appreciated.
This thread has sort of stalled without a resolution. Alex, has your team had the opportunity to weigh in on the subject yet? We have run into a hard situation where MSVC 2012 is missing a feature that we are currently relying on. We made some changes to ASTMatchers to reduce the number of symbols generated in order to not require /bigobj support (see http://reviews.llvm.org/D5485). This change relies on function templates with default arguments, which MSVC does not support (it generates a C4519 error in MSVC 2012), resulting in red bots (http://bb.pgr.jp/builders/ninja-clang-i686-msc17-R/builds/10721). This is a considerably more interesting case (at least to me) than hypothetical benefits -- if we retain MSVC 2012 support, we will also require /bigobj support, have slower compile times for ASTMatcher projects, and slower benchmarks for clang-tidy. This points to concrete benefits to expediting switching away from MSVC 2012, which is why I am pinging this thread again. Thanks! ~Aaron _______________________________________________ lldb-dev mailing list lldb-dev@cs.uiuc.edu http://lists.cs.uiuc.edu/mailman/listinfo/lldb-dev
