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, 14 insertions, 3 deletions

diff --git a/c++tools/configure b/c++tools/configure
index 742816e..8808700 100755
--- a/c++tools/configure
+++ b/c++tools/configure
@@ -627,7 +627,8 @@ get_gcc_base_ver
 EGREP
 GREP
 CXXCPP
-PIEFLAG
+LD_PICFLAG
+PICFLAG
 MAINTAINER
 CXX_AUX_TOOLS
 AUTOHEADER
@@ -700,6 +701,7 @@ enable_c___tools
 enable_maintainer_mode
 enable_checking
 enable_default_pie
+enable_host_pie
 with_gcc_major_version_only
 '
       ac_precious_vars='build_alias
@@ -1333,6 +1335,7 @@ Optional Features:
                           only specific categories of checks. Categories are:
                           yes,no,all,none,release.
   --enable-default-pie    enable Position Independent Executable as default
+  --enable-host-pie       build host code as PIE
 
 Optional Packages:
   --with-PACKAGE[=ARG]    use PACKAGE [ARG=yes]
@@ -2990,12 +2993,20 @@ fi
 # Check whether --enable-default-pie was given.
 # Check whether --enable-default-pie was given.
 if test "${enable_default_pie+set}" = set; then :
-  enableval=$enable_default_pie; PIEFLAG=-fPIE
+  enableval=$enable_default_pie; PICFLAG=-fPIE
 else
-  PIEFLAG=
+  PICFLAG=
 fi
 
 
+# Enable --enable-host-pie
+# Check whether --enable-host-pie was given.
+if test "${enable_host_pie+set}" = set; then :
+  enableval=$enable_host_pie; PICFLAG=-fPIE; LD_PICFLAG=-pie
+fi
+
+
+
 
 # Check if O_CLOEXEC is defined by fcntl