Replace --enable-static-pie with --disable-default-pie

Build glibc programs and tests as PIE by default and enable static-pie
automatically if the architecture and toolchain supports it.

Also add a new configuration option --disable-default-pie to prevent
building programs as PIE.

Only the following architectures now have PIE disabled by default
because they do not work at the moment.  hppa, ia64, alpha and csky
don't work because the linker is unable to handle a pcrel relocation
generated from PIE objects.  The microblaze compiler is currently
failing with an ICE.  GNU hurd tries to enable static-pie, which does
not work and hence fails.  All these targets have default PIE disabled
at the moment and I have left it to the target maintainers to enable PIE
on their targets.

build-many-glibcs runs clean for all targets.  I also tested x86_64 on
Fedora and Ubuntu, to verify that the default build as well as
--disable-default-pie work as expected with both system toolchains.

Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>

1 files changed, 14 insertions, 7 deletions

diff --git a/Makeconfig b/Makeconfig
index 3fa2f13003..775bf12b65 100644
--- a/Makeconfig
+++ b/Makeconfig
@@ -1,4 +1,5 @@
 # Copyright (C) 1991-2021 Free Software Foundation, Inc.
+# Copyright (C) The GNU Toolchain Authors.
 # This file is part of the GNU C Library.
 
 # The GNU C Library is free software; you can redistribute it and/or
@@ -376,19 +377,24 @@ LDFLAGS.so += $(hashstyle-LDFLAGS)
 LDFLAGS-rtld += $(hashstyle-LDFLAGS)
 endif
 
-ifeq (yes,$(enable-static-pie))
+ifeq (no,$(build-pie-default))
+pie-default = $(no-pie-ccflag)
+else # build-pie-default
 pic-default = -DPIC
 # Compile libc.a and libc_p.a with -fPIE/-fpie for static PIE.
 pie-default = $(pie-ccflag)
+
+ifeq (yes,$(enable-static-pie))
 ifeq (yes,$(have-static-pie))
-default-pie-ldflag = -static-pie
+static-pie-ldflag = -static-pie
 else
 # Static PIE can't have dynamic relocations in read-only segments since
 # static PIE is mapped into memory by kernel.  --eh-frame-hdr is needed
 # for PIE to support exception.
-default-pie-ldflag = -Wl,-pie,--no-dynamic-linker,--eh-frame-hdr,-z,text
-endif
-endif
+static-pie-ldflag = -Wl,-pie,--no-dynamic-linker,--eh-frame-hdr,-z,text
+endif # have-static-pie
+endif # enable-static-pie
+endif # build-pie-default
 
 # If lazy relocations are disabled, add the -z now flag.  Use
 # LDFLAGS-lib.so instead of LDFLAGS.so, to avoid adding the flag to
@@ -444,7 +450,7 @@ endif
 # Command for statically linking programs with the C library.
 ifndef +link-static
 +link-static-before-inputs = -nostdlib -nostartfiles -static \
-	      $(if $($(@F)-no-pie),$(no-pie-ldflag),$(default-pie-ldflag)) \
+	      $(if $($(@F)-no-pie),$(no-pie-ldflag),$(static-pie-ldflag)) \
 	      $(sysdep-LDFLAGS) $(LDFLAGS) $(LDFLAGS-$(@F))  \
 	      $(firstword $(CRT-$(@F)) $(csu-objpfx)$(real-static-start-installed-name)) \
 	      $(+preinit) $(+prectorT)
@@ -479,7 +485,7 @@ ifeq (yes,$(build-pie-default))
 +link-tests-after-inputs = $(link-libc-tests) $(+link-pie-after-libc)
 +link-printers-tests = $(+link-pie-printers-tests)
 else  # not build-pie-default
-+link-before-inputs = -nostdlib -nostartfiles \
++link-before-inputs = -nostdlib -nostartfiles $(no-pie-ldflag) \
 	      $(sysdep-LDFLAGS) $(LDFLAGS) $(LDFLAGS-$(@F)) \
 	      $(combreloc-LDFLAGS) $(relro-LDFLAGS) $(hashstyle-LDFLAGS) \
 	      $(firstword $(CRT-$(@F)) $(csu-objpfx)$(start-installed-name)) \
@@ -1040,6 +1046,7 @@ PIC-ccflag = -fPIC
 endif
 # This can be changed by a sysdep makefile
 pie-ccflag = -fpie
+no-pie-ccflag = -fno-pie
 # This one should always stay like this unless there is a very good reason.
 PIE-ccflag = -fPIE
 ifeq (yes,$(build-profile))