On 3/22/12, Benjamin De Kosnik <b...@redhat.com> wrote: > Seems like -fpph doesn't work on the pph branch anymore, and > instead -fpph-gen/-fpph-map/-fpph-hdr are used. > > The thing is, how are these flags used?
-fpph-map=basename Enable reading PPH files, and instead of reading #include "basename.h", read "basename.pph". -fpph-map=mapfile Enable reading pph files, and supply a file of mappings from #include directives to PPH file. The file format is a sequence of lines, each with header and PPH file separated by a tab. -fpph-gen whatever.h -o whatever.pph The -fpph-gen flag says a header is being compiled and a pph file should be generated. > unhelpful wiki page: > http://gcc.gnu.org/wiki/pph Zero user documentation. Hasn't been updated in a while. > Based on invoke.texi, I'm expecting something like this: > > 1. generate > g++ -fpph-gen all.h; > // generates all.pph Add -o. > 2. use > g++ -fpph-hdr=all.h foo.cc > // like -include=all.h, but works with pph files No, that flag doesn't cause any input in and of itself. It just causes the #include to read a different file. > Is this right? Some notes below. The main problem is that users would need to #include <precompiled/stdc++.h> and the compiler would need to provide an implicit mapping. We could probably modify -include to pick up PPH files, but that wasn't in our use model. So, it turns out that the hardest files for PPH to deal with are system headers and C++ standard headers. There are some headers that we do not yet handle right, among others, the atomics header is causing us grief. That header gets include in others and thus infects the others. I think your use is ahead of the implementation, and maybe now is not the time to work on integrating it into the build. > > -benjamin > > 2012-03-22 Benjamin Kosnik <b...@redhat.com> > > * include/Makefile.am (allcreated): Add pph build rule. > (pch1_source): ... to pre_1_source. > (pch2_source): ... to pre_2_source. > (pch3_source): ... to pre_3_source. > (pph_output): New. > (PPH_GEN_FLAGS): New. > * include/Makefile.in: Regenerate. > > Index: include/Makefile.am > =================================================================== > --- include/Makefile.am (revision 185703) > +++ include/Makefile.am (working copy) > @@ -858,7 +858,7 @@ > ${host_builddir}/gthr-default.h > > > -pch1_source = ${glibcxx_srcdir}/include/precompiled/stdc++.h > +pre_1_source = ${glibcxx_srcdir}/include/precompiled/stdc++.h > pch1_output_builddir = ${host_builddir}/stdc++.h.gch > pch1_output_anchor = ${host_builddir}/stdc++.h > pch1_output_installdir = ${host_installdir}/stdc++.h.gch > @@ -866,19 +866,18 @@ > pch1b_output = ${pch1_output_builddir}/O2g.gch > pch1_output = ${pch1a_output} ${pch1b_output} > > -pch2_source = ${glibcxx_srcdir}/include/precompiled/stdtr1c++.h > +pre_2_source = ${glibcxx_srcdir}/include/precompiled/stdtr1c++.h > pch2_output_builddir = ${host_builddir}/stdtr1c++.h.gch > pch2_output_anchor = ${host_builddir}/stdtr1c++.h > pch2_output_installdir = ${host_installdir}/stdtr1c++.h.gch > pch2_output = ${pch2_output_builddir}/O2g.gch > > -pch3_source = ${glibcxx_srcdir}/include/precompiled/extc++.h > +pre_3_source = ${glibcxx_srcdir}/include/precompiled/extc++.h > pch3_output_builddir = ${host_builddir}/extc++.h.gch > pch3_output_anchor = ${host_builddir}/extc++.h > pch3_output_installdir = ${host_installdir}/extc++.h.gch > pch3_output = ${pch3_output_builddir}/O2g.gch > > - > pch_output = ${pch1_output} ${pch2_output} ${pch3_output} > pch_output_dirs = \ > ${pch1_output_builddir} ${pch2_output_builddir} > ${pch3_output_builddir} @@ -891,6 +890,9 @@ > pch_build = > endif > > +pph_output = ${host_builddir}/stdc++.h.pph > +PPH_GEN_FLAGS = -x c++-header -nostdinc++ -fpph-gen > + The -x flag is not needed. > # List of all timestamp files. By keeping only one copy of this list, > both # CLEANFILES and all-local are kept up-to-date. > allstamped = \ > @@ -904,7 +906,8 @@ > allcreated = \ > ${host_builddir}/c++config.h \ > ${thread_host_headers} \ > - ${pch_build} > + ${pch_build} \ > + ${pph_output} > > # Here are the rules for building the headers > all-local: ${allstamped} ${allcreated} > @@ -1153,25 +1156,30 @@ > < $< > $@ > > # Build two precompiled C++ includes, stdc++.h.gch/*.gch > -${pch1a_output}: ${allstamped} ${host_builddir}/c++config.h > ${pch1_source} +${pch1a_output}: ${allstamped} > ${host_builddir}/c++config.h ${pre_1_source} -mkdir -p > ${pch1_output_builddir} > - $(CXX) $(PCHFLAGS) $(AM_CPPFLAGS) -O2 -g -std=gnu++0x > ${pch1_source} \ > + $(CXX) $(PCHFLAGS) $(AM_CPPFLAGS) -O2 -g -std=gnu++0x > ${pre_1_source} \ -o $@ > > -${pch1b_output}: ${allstamped} ${host_builddir}/c++config.h > ${pch1_source} +${pch1b_output}: ${allstamped} > ${host_builddir}/c++config.h ${pre_1_source} -mkdir -p > ${pch1_output_builddir} > - $(CXX) $(PCHFLAGS) $(AM_CPPFLAGS) -O2 -g ${pch1_source} -o $@ > + $(CXX) $(PCHFLAGS) $(AM_CPPFLAGS) -O2 -g ${pre_1_source} -o $@ The command line is not a direct replacement for PCH. Separate rules? > > # Build a precompiled TR1 include, stdtr1c++.h.gch/O2.gch > -${pch2_output}: ${pch2_source} ${pch1_output} > +${pch2_output}: ${pre_2_source} ${pch1_output} > -mkdir -p ${pch2_output_builddir} > - $(CXX) $(PCHFLAGS) $(AM_CPPFLAGS) -O2 -g ${pch2_source} -o $@ > + $(CXX) $(PCHFLAGS) $(AM_CPPFLAGS) -O2 -g ${pre_2_source} -o $@ > > # Build a precompiled extension include, extc++.h.gch/O2.gch > -${pch3_output}: ${pch3_source} ${pch2_output} > +${pch3_output}: ${pre_3_source} ${pch2_output} > -mkdir -p ${pch3_output_builddir} > - $(CXX) $(PCHFLAGS) $(AM_CPPFLAGS) -O2 -g ${pch3_source} -o $@ > + $(CXX) $(PCHFLAGS) $(AM_CPPFLAGS) -O2 -g ${pre_3_source} -o $@ > > +# Build a preprocessed C++ include stdc++.h.pph > +pph: ${pph_output} > +${pph_output}: ${allstamped} ${host_builddir}/c++config.h > ${pre_1_source} > + $(CXX) $(PPH_GEN_FLAGS) $(AM_CPPFLAGS) -O2 -g ${pre_1_source} > -o $@ + > # For robustness sake (in light of junk files or in-source > # configuration), copy from the build or source tree to the install > # tree using only the human-maintained file lists and directory > @@ -1291,7 +1299,7 @@ > $(INSTALL_DATA) $${file} $(DESTDIR)${host_installdir}; done > > # By adding these files here, automake will remove them for 'make > clean' -CLEANFILES = ${pch_output} ${pch_output_anchors} stamp-host > +CLEANFILES = ${pch_output} ${pch_output_anchors} ${pph_output} > stamp-host > # To remove directories. > clean-local: -- Lawrence Crowl
