[Rd] Default R-3.4.0 RC CXXFLAGS without -O2 on x86_64-linux-gnu with g++-5.4.0 causes WARNING from stl_list.h

[Martyn Plummer]

This is fixed in R-rc_2017-04-19_r72555.tar.gz

If you are affected by this issue then please test the RC tarball. This
is the last chance to detect problems (including those created by the
last-minute patch) before the release of R 3.4.0.

Martyn

On Wed, 2017-04-19 at 12:19 +0000, Neumann, Steffen wrote:
> Hi r-devel,
> 
> a recent install of R-3.4.0 RC (2017-04-13 r72510) 
> on Linux (Ubuntu 16.04.1 LTS) x86_64-linux-gnu 
> with g++ (Ubuntu 5.4.0-6ubuntu1~16.04.4) 5.4.0 20160609
> (see http://bioconductor.org/checkResults/devel/bioc-LATEST/malbec2-N
> odeInfo.html for more) 
> results in CXXFLAGS not containing "-O2" as optimisation flag,
> there is only "	-Wall", while CFLAGS are happy with "-g -O2
> -Wall"
> 
> This has an influence in at least one place
> https://stat.ethz.ch/pipermail/bioc-devel/2017-April/010733.html
> where we have WARNINGS in R CMD check from "Found ‘abort’, 
> possibly from ‘abort’ (C)" in packages xcms/mzR.
> The abort() call is not coming from XCMS, but rather 
> from the C++ code in the STL:
> 
> 	[...]
> 	# 1770 "/usr/include/c++/5/bits/stl_list.h"
> 	void _M_check_equal_allocators(list& __x) {
> 	 if (_M_get_Node_allocator())
> 	   __builtin_abort();
> 	}
> 
> If we compile with -O2 optimisation, this getting rid of 
> the abort() symbol, as shown 
> in https://github.com/sneumann/xcms/issues/150#issuecomment-293545521
> 
> Martin Morgan created a minimum example that shows that 
> the symbol is indeed deep down in the STL (see below and in:
> https://stat.ethz.ch/pipermail/bioc-devel/2017-April/010837.html )
> 
> This raises several questions:
> 
> 1) is there any way to avoid the WARNING / abort() inside 
>    the STL list implementation ? Or just live with it ?
> 
> 2) If not, is there a reason why the Bioconductor build farm 
>    Ubuntu machine is not using -O2 as default CXXFLAG ?
>    BioC admins are trying to have a vanilla R installation with
> defaults. 
>    According to Herve Pages, CXXFLAGS without -O2 is default 
>    since R-3.4 beta, but I don't know enough about the package 
>    build logic to point to a particular R commit. 
> 
> 3) I thought about cheating the system and add -O2 
>    in the package CXXFLAGS, but Martin Morgan 
>    recommends packages shouldn't mess and override system build
> defaults
>    to mask and paper over the actual issue having a nasty abort() 
>    lurking somewhere.
>    But I couldn't add PKG_CXXFLAGS=-O2 in first place, since that 
>    triggers the different WARNING that -O2 is not portable. 
> 
> => Any help and input would be highly appreciated. 
> 
> Thanks in advance, 
> yours,
> Steffen
> 
> 
> tmp.cpp by Martin Morgan (also in above linked mail thread)
> -------
> #include <list>
> 
> int foo(int argc, const char *argv[]) {
>      std::list<int> l1, l2;
>      std::list<int>::iterator it;
> 
>      it = l1.begin();
>      l1.splice (it, l2); // mylist1: 1 10 20 30 2 3 4
> 
>      return 0;
> }
> -------
> 
> Test with
> 
>    rm -f tmp.o && R CMD SHLIB tmp.cpp && nm tmp.o | grep abort
> 
> with compiler settings in ~/.R/Makevars with/without -O2 
> -------------
> CXXFLAGS = -g -O0
> -------------
> 
> 
> 
> 
> 
> --
> IPB Halle                    AG Massenspektrometrie &
> Bioinformatik
> Dr. Steffen Neumann          http://www.IPB-Halle.DE
> Weinberg 3                   Tel. +49 (0) 345 5582 - 1470
> 06120 Halle                       +49 (0) 345 5582 - 0           
> sneumann(at)IPB-Halle.DE     Fax. +49 (0) 345 5582 - 1409
> 
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