configure: Implement --enable-host-pie

This patch implements the --enable-host-pie configure option which
makes the compiler executables PIE.  This can be used to enhance
protection against ROP attacks, and can be viewed as part of a wider
trend to harden binaries.

It is similar to the option --enable-host-shared, except that --e-h-s
won't add -shared to the linker flags whereas --e-h-p will add -pie.
It is different from --enable-default-pie because that option just
adds an implicit -fPIE/-pie when the compiler is invoked, but the
compiler itself isn't PIE.

Since r12-5768-gfe7c3ecf, PCH works well with PIE, so there are no PCH
regressions.

When building the compiler, the build process may use various in-tree
libraries; these need to be built with -fPIE so that it's possible to
use them when building a PIE.  For instance, when --with-included-gettext
is in effect, intl object files must be compiled with -fPIE.  Similarly,
when building in-tree gmp, isl, mpfr and mpc, they must be compiled with
-fPIE.

I plan to add an option to link with -Wl,-z,now.

ChangeLog:

	* Makefile.def: Pass $(PICFLAG) to AM_CFLAGS for gmp, mpfr, mpc, and
	isl.
	* Makefile.in: Regenerate.
	* Makefile.tpl: Set PICFLAG.
	* configure.ac (--enable-host-pie): New check.  Set PICFLAG after this
	check.
	* configure: Regenerate.

c++tools/ChangeLog:

	* Makefile.in: Rename PIEFLAG to PICFLAG.  Set LD_PICFLAG.  Use it.
	Use pic/libiberty.a if PICFLAG is set.
	* configure.ac (--enable-default-pie): Set PICFLAG instead of PIEFLAG.
	(--enable-host-pie): New check.
	* configure: Regenerate.

fixincludes/ChangeLog:

	* Makefile.in: Set and use PICFLAG and LD_PICFLAG.  Use the "pic"
	build of libiberty if PICFLAG is set.
	* configure.ac:
	* configure: Regenerate.

gcc/ChangeLog:

	* Makefile.in: Set LD_PICFLAG.  Use it.  Set enable_host_pie.
	Remove NO_PIE_CFLAGS and NO_PIE_FLAG.  Pass LD_PICFLAG to
	ALL_LINKERFLAGS.  Use the "pic" build of libiberty if --enable-host-pie.
	* configure.ac (--enable-host-shared): Don't set PICFLAG here.
	(--enable-host-pie): New check.  Set PICFLAG and LD_PICFLAG after this
	check.
	* configure: Regenerate.
	* doc/install.texi: Document --enable-host-pie.

gcc/d/ChangeLog:

	* Make-lang.in: Remove NO_PIE_CFLAGS.

intl/ChangeLog:

	* Makefile.in: Use @PICFLAG@ in COMPILE as well.
	* configure.ac (--enable-host-shared): Don't set PICFLAG here.
	(--enable-host-pie): New check.  Set PICFLAG after this check.
	* configure: Regenerate.

libcody/ChangeLog:

	* Makefile.in: Pass LD_PICFLAG to LDFLAGS.
	* configure.ac (--enable-host-shared): Don't set PICFLAG here.
	(--enable-host-pie): New check.  Set PICFLAG and LD_PICFLAG after this
	check.
	* configure: Regenerate.

libcpp/ChangeLog:

	* configure.ac (--enable-host-shared): Don't set PICFLAG here.
	(--enable-host-pie): New check.  Set PICFLAG after this check.
	* configure: Regenerate.

libdecnumber/ChangeLog:

	* configure.ac (--enable-host-shared): Don't set PICFLAG here.
	(--enable-host-pie): New check.  Set PICFLAG after this check.
	* configure: Regenerate.

libiberty/ChangeLog:

	* configure.ac: Also set shared when enable_host_pie.
	* configure: Regenerate.

zlib/ChangeLog:

	* configure.ac (--enable-host-shared): Don't set PICFLAG here.
	(--enable-host-pie): New check.  Set PICFLAG after this check.
	* configure: Regenerate.

1 files changed, 33 insertions, 14 deletions

diff --git a/gcc/configure b/gcc/configure
index aa09609..f631830 100755
--- a/gcc/configure
+++ b/gcc/configure
@@ -632,10 +632,10 @@ ac_includes_default="\
 ac_subst_vars='LTLIBOBJS
 LIBOBJS
 CET_HOST_FLAGS
-NO_PIE_FLAG
-NO_PIE_CFLAGS
-enable_default_pie
+LD_PICFLAG
 PICFLAG
+enable_default_pie
+enable_host_pie
 enable_host_shared
 enable_plugin
 pluginlibs
@@ -1025,6 +1025,7 @@ enable_link_serialization
 enable_version_specific_runtime_libs
 enable_plugin
 enable_host_shared
+enable_host_pie
 enable_libquadmath_support
 with_linker_hash_style
 with_diagnostics_color
@@ -1787,6 +1788,7 @@ Optional Features:
                           in a compiler-specific directory
   --enable-plugin         enable plugin support
   --enable-host-shared    build host code as shared libraries
+  --enable-host-pie       build host code as PIE
   --disable-libquadmath-support
                           disable libquadmath support for Fortran
   --enable-default-pie    enable Position Independent Executable as default
@@ -19710,7 +19712,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 19713 "configure"
+#line 19727 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -19816,7 +19818,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 19819 "configure"
+#line 19833 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -31945,13 +31947,17 @@ fi
 # Enable --enable-host-shared
 # Check whether --enable-host-shared was given.
 if test "${enable_host_shared+set}" = set; then :
-  enableval=$enable_host_shared; PICFLAG=-fPIC
-else
-  PICFLAG=
+  enableval=$enable_host_shared;
 fi
 
 
 
+# Enable --enable-host-pie
+# Check whether --enable-host-pie was given.
+if test "${enable_host_pie+set}" = set; then :
+  enableval=$enable_host_pie;
+fi
+
 
 
 # Check whether --enable-libquadmath-support was given.
@@ -32105,10 +32111,6 @@ rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
 fi
 { $as_echo "$as_me:${as_lineno-$LINENO}: result: $gcc_cv_c_no_fpie" >&5
 $as_echo "$gcc_cv_c_no_fpie" >&6; }
-if test "$gcc_cv_c_no_fpie" = "yes"; then
-  NO_PIE_CFLAGS="-fno-PIE"
-fi
-
 
 # Check if -no-pie works.
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for -no-pie option" >&5
@@ -32133,11 +32135,28 @@ rm -f core conftest.err conftest.$ac_objext \
 fi
 { $as_echo "$as_me:${as_lineno-$LINENO}: result: $gcc_cv_no_pie" >&5
 $as_echo "$gcc_cv_no_pie" >&6; }
-if test "$gcc_cv_no_pie" = "yes"; then
-  NO_PIE_FLAG="-no-pie"
+
+if test x$enable_host_shared = xyes; then
+  PICFLAG=-fPIC
+elif test x$enable_host_pie = xyes; then
+  PICFLAG=-fPIE
+elif test x$gcc_cv_c_no_fpie = xyes; then
+  PICFLAG=-fno-PIE
+else
+  PICFLAG=
+fi
+
+if test x$enable_host_pie = xyes; then
+  LD_PICFLAG=-pie
+elif test x$gcc_cv_no_pie = xyes; then
+  LD_PICFLAG=-no-pie
+else
+  LD_PICFLAG=
 fi
 
 
+
+
 # Enable Intel CET on Intel CET enabled host if jit is enabled.
  # Check whether --enable-cet was given.
 if test "${enable_cet+set}" = set; then :