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, 21 insertions, 1 deletions

diff --git a/libdecnumber/configure b/libdecnumber/configure
index fb6db05565a..84bc4ffc767 100755
--- a/libdecnumber/configure
+++ b/libdecnumber/configure
@@ -626,6 +626,8 @@ ac_subst_vars='LTLIBOBJS
 LIBOBJS
 CET_HOST_FLAGS
 PICFLAG
+enable_host_pie
+enable_host_shared
 ADDITIONAL_OBJS
 enable_decimal_float
 target_os
@@ -706,6 +708,7 @@ enable_werror_always
 enable_maintainer_mode
 enable_decimal_float
 enable_host_shared
+enable_host_pie
 enable_cet
 '
       ac_precious_vars='build_alias
@@ -1338,6 +1341,7 @@ Optional Features:
 			or 'dpd' choses which decimal floating point format
 			to use
   --enable-host-shared    build host code as shared libraries
+  --enable-host-pie       build host code as PIE
   --enable-cet            enable Intel CET in host libraries [default=auto]
 
 Some influential environment variables:
@@ -5186,7 +5190,23 @@ $as_echo "#define AC_APPLE_UNIVERSAL_BUILD 1" >>confdefs.h
 # Enable --enable-host-shared.
 # Check whether --enable-host-shared was given.
 if test "${enable_host_shared+set}" = set; then :
-  enableval=$enable_host_shared; PICFLAG=-fPIC
+  enableval=$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
+
+
+
+if test x$enable_host_shared = xyes; then
+  PICFLAG=-fPIC
+elif test x$enable_host_pie = xyes; then
+  PICFLAG=-fPIE
 else
   PICFLAG=
 fi