On Tue, Sep 7, 2021 at 10:11 PM Iain Sandoe <i...@sandoe.co.uk> wrote: > > Hi Folks, > > So, looking through the various email threads and the PR, I think that > what has happened is : > > As the PR points out, our existing PCH model does not work if the compiler > executable is PIE - which manifests on platforms like Darwin (which is PIE > by default) or Linux when configured —enable-default-pie. > > H.J’s original patch forces no-PIE onto the compiler executables, and > because of shared code on $host also to the driver etc. > > However, the patch also forces no-PIE onto executables that run on > $build (e.g. the generators etc) which is not needed (and breaks bootstrap > for at least one case, albeit one not often tested). > > Marcus, observed that there was no separation in the treatment of $build > and $host, and a follow-on patch was applied that made the no-PIE change > to $build distinct. > > However, IMHO, the correct change there would really be to remove the > code applying no-PIE to $build (where it is not required). > > The patch below makes this change and thus fixes the bootstrap regression. > > Testing - all supported languages : > > x86_64, powerpc64le, powerpc64, aarch64 - linux > x64_64, powerpc, i686 - darwin > aix (nop, since ASLR is not used) > solaris, thanks to Rainer (since the machine on the cfarm doesn’t support > PIE). > > All Linux platforms configured —enable-default-pie (without which one > cannot observe this anyway). > > crosses and “canadians” (actually all those here are $target=$host). > > $build = x86_64-linux, $host=$target = aarch64-linux > $build = powerpcle-linux $host=$target = x86_64-linux > $build= x86_64-darwin, $target = powerpc-darwin > $build = x86_64-darwin $host=$target=aarch64-darwin20 > > The seems to be a problem in building the native-crossed libgo, but that > is not a result of this patch. Other than this - nothing untoward is observed > and I’ve manually checked that the $build exes are PIE and the $host ones > are not... > > OK for master, and eventually backports?
OK for trunk, I think it warrants quite some soaking time before considering backports. Thanks, Richard. > Iain > > > [1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71934 > [2] https://gcc.gnu.org/pipermail/gcc-patches/2015-October/432180.html > [3] https://gcc.gnu.org/pipermail/gcc-patches/2021-August/578169.html > > —— commit log > > The executables for GCC's c-family compilers must be built with no-PIE > because they use PCH and the current model for this requires that the > exe is always lauched at the same address. Since the other language > compilers share code with the c-family this constraint is also applied > to them. > > However, the executables that run on $build (generators, and parsers > for md and def files) need not have any such constraint; they do not > consume PCH files. > > This change simplifies the configuration and Makefile content by > removing the code enforcing no-PIE on these exes. This also fixes a > bootstrap issue with some Darwin versions and clang as the bootstrap > compiler, where -no-PIE causes the correct relocation model to be > switched off leading to invalid user-space code. > > Signed-off-by: Iain Sandoe <i...@sandoe.co.uk> > > gcc/ChangeLog: > > * Makefile.in: Remove variables related to applying no-PIE > to the exes on $build. > * configure: Regenerate. > * configure.ac: Remove configuration related to applying > no-PIE to the exes on $build. > --- > gcc/Makefile.in | 7 ------- > gcc/configure | 18 ++---------------- > gcc/configure.ac | 10 ---------- > 3 files changed, 2 insertions(+), 33 deletions(-) > > diff --git a/gcc/Makefile.in b/gcc/Makefile.in > index f0c560fe45b..d0c5ca214c9 100644 > --- a/gcc/Makefile.in > +++ b/gcc/Makefile.in > @@ -799,13 +799,8 @@ DIR = ../gcc > # Native compiler for the build machine and its switches. > CC_FOR_BUILD = @CC_FOR_BUILD@ > CXX_FOR_BUILD = @CXX_FOR_BUILD@ > -NO_PIE_CFLAGS_FOR_BUILD = @NO_PIE_CFLAGS_FOR_BUILD@ > -NO_PIE_FLAG_FOR_BUILD = @NO_PIE_FLAG_FOR_BUILD@ > BUILD_CFLAGS= @BUILD_CFLAGS@ $(GENERATOR_CFLAGS) -DGENERATOR_FILE > BUILD_CXXFLAGS = @BUILD_CXXFLAGS@ $(GENERATOR_CFLAGS) -DGENERATOR_FILE > -BUILD_NO_PIE_CFLAGS = @BUILD_NO_PIE_CFLAGS@ > -BUILD_CFLAGS += $(BUILD_NO_PIE_CFLAGS) > -BUILD_CXXFLAGS += $(BUILD_NO_PIE_CFLAGS) > > # Native compiler that we use. This may be C++ some day. > COMPILER_FOR_BUILD = $(CXX_FOR_BUILD) > @@ -817,8 +812,6 @@ BUILD_LINKERFLAGS = $(BUILD_CXXFLAGS) > > # Native linker and preprocessor flags. For x-fragment overrides. > BUILD_LDFLAGS=@BUILD_LDFLAGS@ > -BUILD_NO_PIE_FLAG = @BUILD_NO_PIE_FLAG@ > -BUILD_LDFLAGS += $(BUILD_NO_PIE_FLAG) > BUILD_CPPFLAGS= -I. -I$(@D) -I$(srcdir) -I$(srcdir)/$(@D) \ > -I$(srcdir)/../include @INCINTL@ $(CPPINC) $(CPPFLAGS) > > diff --git a/gcc/configure b/gcc/configure > index 500e3f68215..87d7b9c435b 100755 > --- a/gcc/configure > +++ b/gcc/configure > @@ -753,10 +753,6 @@ FGREP > SED > LIBTOOL > collect2 > -NO_PIE_FLAG_FOR_BUILD > -NO_PIE_CFLAGS_FOR_BUILD > -BUILD_NO_PIE_FLAG > -BUILD_NO_PIE_CFLAGS > STMP_FIXINC > BUILD_LDFLAGS > BUILD_CXXFLAGS > @@ -13336,24 +13332,14 @@ BUILD_CXXFLAGS='$(ALL_CXXFLAGS)' > BUILD_LDFLAGS='$(LDFLAGS)' > STMP_FIXINC=stmp-fixinc > > -BUILD_NO_PIE_CFLAGS='$(NO_PIE_CFLAGS)' > -BUILD_NO_PIE_FLAG='$(NO_PIE_FLAG)' > - > # And these apply if build != host, or we are generating coverage data > if test x$build != x$host || test "x$coverage_flags" != x > then > BUILD_CFLAGS='$(INTERNAL_CFLAGS) $(T_CFLAGS) $(CFLAGS-$@) > $(CFLAGS_FOR_BUILD)' > BUILD_CXXFLAGS='$(INTERNAL_CFLAGS) $(T_CFLAGS) $(CFLAGS-$@) > $(CXXFLAGS_FOR_BUILD)' > BUILD_LDFLAGS='$(LDFLAGS_FOR_BUILD)' > - > - NO_PIE_CFLAGS_FOR_BUILD=${NO_PIE_CFLAGS_FOR_BUILD-${NO_PIE_CFLAGS}} > - NO_PIE_FLAG_FOR_BUILD=${NO_PIE_FLAG_FOR_BUILD-${NO_PIE_FLAG}} > - BUILD_NO_PIE_CFLAGS='$(NO_PIE_CFLAGS_FOR_BUILD)' > - BUILD_NO_PIE_FLAG='$(NO_PIE_FLAG_FOR_BUILD)' > fi > > - > - > # Expand extra_headers to include complete path. > # This substitutes for lots of t-* files. > extra_headers_list= > @@ -19480,7 +19466,7 @@ else > lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2 > lt_status=$lt_dlunknown > cat > conftest.$ac_ext <<_LT_EOF > -#line 19483 "configure" > +#line 19469 "configure" > #include "confdefs.h" > > #if HAVE_DLFCN_H > @@ -19586,7 +19572,7 @@ else > lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2 > lt_status=$lt_dlunknown > cat > conftest.$ac_ext <<_LT_EOF > -#line 19589 "configure" > +#line 19575 "configure" > #include "confdefs.h" > > #if HAVE_DLFCN_H > diff --git a/gcc/configure.ac b/gcc/configure.ac > index 6f768e02aa4..3ba78aa9dee 100644 > --- a/gcc/configure.ac > +++ b/gcc/configure.ac > @@ -2473,23 +2473,13 @@ BUILD_CXXFLAGS='$(ALL_CXXFLAGS)' > AC_SUBST(BUILD_CXXFLAGS) > BUILD_LDFLAGS='$(LDFLAGS)' AC_SUBST(BUILD_LDFLAGS) > STMP_FIXINC=stmp-fixinc AC_SUBST(STMP_FIXINC) > > -BUILD_NO_PIE_CFLAGS='$(NO_PIE_CFLAGS)' AC_SUBST(BUILD_NO_PIE_CFLAGS) > -BUILD_NO_PIE_FLAG='$(NO_PIE_FLAG)' AC_SUBST(BUILD_NO_PIE_FLAG) > - > # And these apply if build != host, or we are generating coverage data > if test x$build != x$host || test "x$coverage_flags" != x > then > BUILD_CFLAGS='$(INTERNAL_CFLAGS) $(T_CFLAGS) $(CFLAGS-$@) > $(CFLAGS_FOR_BUILD)' > BUILD_CXXFLAGS='$(INTERNAL_CFLAGS) $(T_CFLAGS) $(CFLAGS-$@) > $(CXXFLAGS_FOR_BUILD)' > BUILD_LDFLAGS='$(LDFLAGS_FOR_BUILD)' > - > - NO_PIE_CFLAGS_FOR_BUILD=${NO_PIE_CFLAGS_FOR_BUILD-${NO_PIE_CFLAGS}} > - NO_PIE_FLAG_FOR_BUILD=${NO_PIE_FLAG_FOR_BUILD-${NO_PIE_FLAG}} > - BUILD_NO_PIE_CFLAGS='$(NO_PIE_CFLAGS_FOR_BUILD)' > - BUILD_NO_PIE_FLAG='$(NO_PIE_FLAG_FOR_BUILD)' > fi > -AC_SUBST(NO_PIE_CFLAGS_FOR_BUILD) > -AC_SUBST(NO_PIE_FLAG_FOR_BUILD) > > # Expand extra_headers to include complete path. > # This substitutes for lots of t-* files. > -- >
