Date: Sun, 15 Nov 2009 10:58:17 +0100 From: Remko Lodder <remko@elvandar.org> To: Rene Ladan <rene@FreeBSD.org> Cc: Perforce Change Reviews <perforce@FreeBSD.org> Subject: Re: PERFORCE change 170633 for review Message-ID: <1D8EE757-D3A6-43D1-B8CF-40BBE46A8796@elvandar.org> In-Reply-To: <200911142333.nAENXWrT017367@repoman.freebsd.org> References: <200911142333.nAENXWrT017367@repoman.freebsd.org>
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On Nov 15, 2009, at 12:33 AM, Rene Ladan wrote: > http://p4web.freebsd.org/chv.cgi?CH=170633 > > Change 170633 by rene@rene_self on 2009/11/14 23:32:57 > > [porters handbook] > Add a section about Clang to the "Dos and Don'ts" chapter. > To be reviewed by the clang team and the doc review team. > > Affected files ... > > .. //depot/projects/docproj_nl/en_US.ISO8859-1/books/porters-handbook/book.sgml#50 edit > > Differences ... > > ==== //depot/projects/docproj_nl/en_US.ISO8859-1/books/porters-handbook/book.sgml#50 (text+ko) ==== > > @@ -13602,6 +13602,92 @@ > shorthand solution.</para> > </sect1> > > + <sect1 id="dads-clang"> > + <title>Clang: new C/C++ compiler</title> > + > + <para>A future version of &os; will likely have the Clang C/C++ > + compiler as its base compiler. Some modifications to the Ports > + Collection are necessary. In general, these are <quote>write proper > + ports</quote> and <quote>write proper source code</quote>. More > + specifically:</para> > + > + <itemizedlist> > + <listitem> > + <para>Respect <makevar>CC</makevar> and <makevar>CXX</makevar>. Do ^^^ You should probably add something like 'variables' on the end of the line. > + not any of <filename>cc</filename>, <filename>c99</filename>, > + <filename>gcc</filename>, <filename>c++</filename>, or > + <filename>g++</filename> directly.</para> What shouldn't we do with 'cc' 'c99' etc? I think we should be more specific here in terms of 'do not use <filename>cc</filename>[..] directly. > + </listitem> > + > + <listitem> > + <para>Respect <makevar>LD</makevar>, do not use > + <filename>ld</filename> directly.</para> > + </listitem> > + > + <listitem> > + <para>Do not use <filename>cpp</filename> for reformatting manual > + pages or shell scripts. Try to use something more suitable > + instead, possibly falling back to <makevar>CPP</makevar>.</para> > + <!-- (rene) what about the C++ preprocessor? --> > + </listitem> > + > + <listitem> > + <para>If there are link errors related to missing or already > + defined functions, try to add <makevar>CSTD=gnu89</makevar> to > + <filename>Makefile</filename>. The function vsnprintf() is > + already built in.</para> > + </listitem> > + > + <listitem> > + <para>The <literal>-traditional</literal> option is not supported, > + so existing occurences have to be removed. No concensus has yet > + been reached on ports abusing this option to preserve white space > + in text formatting. Note that the Clang preprocessor does not > + preserve white space.</para> > + </listitem> > + > + <listitem> > + <para>Explicit type indication of variables must be used in > + built-in assembler code.</para> > + </listitem> > + > + <listitem> > + <para>The main function must be properly declared as</para> ^^^ add : > + > + <programlisting>int main(int argc, char **argv)</programlisting> > + </listitem> > + > + <listitem> > + <para>The maximum useable optimization level is 3. Level 4 is > + reserved for link-time optimization for the Clang backend.</para> > + </listitem> > + > + <!--(rene) -I and -L belong to CONFIGURE_ENV, not to CFLAGS (?)--> > + </itemizedlist> > + > + <para>Some temporary hacks that might be used if all else fails:</para> > + > + <itemizedlist> > + <listitem> > + <para>Adding <literal>-fheinous-gnu-extensions</literal>. Note > + that this option is already deprecated.</para> > + </listitem> > + > + <listitem> > + <para>Reducing the warning level by adding > + <literal>--diasable-werror</literal> or > + <literal>--disable-strict</literal>, or by disabling > + <literal>--warn-common</literal> or > + <literal>-Werror</literal>.</para> > + </listitem> > + </itemizedlist> > + > +<!-- > + <para>A current set of patches are available at <ulink > + url="http://www.rainbow-runner.nl/clang/patches">this patch site</ulink>.</para> > +--> > + </sect1> > + > <sect1 id="dads-cc"> > <title>Respect both <makevar>CC</makevar> and > <makevar>CXX</makevar></title> Thanks for making this! -- /"\ Best regards, | remko@FreeBSD.org \ / Remko Lodder | remko@EFnet X http://www.evilcoder.org/ | / \ ASCII Ribbon Campaign | Against HTML Mail and News
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