[ARM/FDPIC v6 03/24] [ARM] FDPIC: Force FDPIC related options unless -mno-fdpic is provided

[Christophe Lyon <christophe dot lyon at st dot com>]

From: Christophe Lyon <christophe.lyon@linaro.org>

In FDPIC mode, we set -fPIE unless the user provides -fno-PIE, -fpie,
-fPIC or -fpic: indeed FDPIC code is PIC, but we want to generate code
for executables rather than shared libraries by default.

We also make sure to use the --fdpic assembler option, and select the
appropriate linker emulation.

At link time, we also default to -pie, unless we are generating a
shared library or a relocatable file (-r). Note that static link is
not supported as it requires specifying the dynamic linker because the
executable still has to relocate itself at startup.

We also force 'now' binding since lazy binding is not supported.

We should also apply the same behavior for -Wl,-Ur as for -r, but I
couldn't find how to describe that in the specs fragment.

2019-XX-XX  Christophe Lyon  <christophe.lyon@st.com>
	Mickaël Guêné <mickael.guene@st.com>

	gcc/
	* config.gcc: Handle arm*-*-uclinuxfdpiceabi.
	* config/arm/bpabi.h (TARGET_FDPIC_ASM_SPEC): New.
	(SUBTARGET_EXTRA_ASM_SPEC): Use TARGET_FDPIC_ASM_SPEC.
	* config/arm/linux-eabi.h (FDPIC_CC1_SPEC): New.
	(CC1_SPEC): Use FDPIC_CC1_SPEC.
	(MUSL_DYNAMIC_LINKER): Add -fdpic suffix when needed.
	* config/arm/uclinuxfdpiceabi.h: New file.

	libsanitizer/
	* configure.tgt (arm*-*-*fdpiceabi): Sanitizers are
	unsupported in this configuration.

Change-Id: I74ac1fbb2e809e864d2b0acce66b173e76bcf92b

diff --git a/gcc/config.gcc b/gcc/config.gcc
index 69904fd..2a6a8f0 100644
--- a/gcc/config.gcc
+++ b/gcc/config.gcc
@@ -1208,6 +1208,11 @@ arm*-*-linux-* | arm*-*-uclinuxfdpiceabi)
 	esac
 	tmake_file="${tmake_file} arm/t-arm arm/t-arm-elf arm/t-bpabi arm/t-linux-eabi"
 	tm_file="$tm_file arm/bpabi.h arm/linux-eabi.h arm/aout.h arm/arm.h"
+	case $target in
+	arm*-*-uclinuxfdpiceabi)
+	    tm_file="$tm_file arm/uclinuxfdpiceabi.h"
+	    ;;
+	esac
 	# Generation of floating-point instructions requires at least ARMv5te.
 	if [ "$with_float" = "hard" -o "$with_float" = "softfp" ] ; then
 	    target_cpu_cname="arm10e"
diff --git a/gcc/config/arm/bpabi.h b/gcc/config/arm/bpabi.h
index e1bacf4..75d9a99 100644
--- a/gcc/config/arm/bpabi.h
+++ b/gcc/config/arm/bpabi.h
@@ -55,6 +55,8 @@
 #define TARGET_FIX_V4BX_SPEC " %{mcpu=arm8|mcpu=arm810|mcpu=strongarm*"\
   "|march=armv4|mcpu=fa526|mcpu=fa626:--fix-v4bx}"
 
+#define TARGET_FDPIC_ASM_SPEC ""
+
 #define BE8_LINK_SPEC							\
   "%{!r:%{!mbe32:%:be8_linkopt(%{mlittle-endian:little}"		\
   "			       %{mbig-endian:big}"			\
@@ -64,7 +66,8 @@
 /* Tell the assembler to build BPABI binaries.  */
 #undef  SUBTARGET_EXTRA_ASM_SPEC
 #define SUBTARGET_EXTRA_ASM_SPEC \
-  "%{mabi=apcs-gnu|mabi=atpcs:-meabi=gnu;:-meabi=5}" TARGET_FIX_V4BX_SPEC
+  "%{mabi=apcs-gnu|mabi=atpcs:-meabi=gnu;:-meabi=5}" TARGET_FIX_V4BX_SPEC \
+  TARGET_FDPIC_ASM_SPEC
 
 #ifndef SUBTARGET_EXTRA_LINK_SPEC
 #define SUBTARGET_EXTRA_LINK_SPEC ""
diff --git a/gcc/config/arm/linux-eabi.h b/gcc/config/arm/linux-eabi.h
index 66ec0ea..b348971 100644
--- a/gcc/config/arm/linux-eabi.h
+++ b/gcc/config/arm/linux-eabi.h
@@ -89,7 +89,7 @@
 #define MUSL_DYNAMIC_LINKER_E "%{mbig-endian:eb}"
 #endif
 #define MUSL_DYNAMIC_LINKER \
-  "/lib/ld-musl-arm" MUSL_DYNAMIC_LINKER_E "%{mfloat-abi=hard:hf}.so.1"
+  "/lib/ld-musl-arm" MUSL_DYNAMIC_LINKER_E "%{mfloat-abi=hard:hf}%{mfdpic:-fdpic}.so.1"
 
 /* At this point, bpabi.h will have clobbered LINK_SPEC.  We want to
    use the GNU/Linux version, not the generic BPABI version.  */
@@ -101,9 +101,12 @@
 #undef  ASAN_CC1_SPEC
 #define ASAN_CC1_SPEC "%{%:sanitize(address):-funwind-tables}"
 
+#define FDPIC_CC1_SPEC ""
+
 #undef  CC1_SPEC
 #define CC1_SPEC							\
-  LINUX_OR_ANDROID_CC (GNU_USER_TARGET_CC1_SPEC " " ASAN_CC1_SPEC,	\
+  LINUX_OR_ANDROID_CC (GNU_USER_TARGET_CC1_SPEC " " ASAN_CC1_SPEC " "	\
+		       FDPIC_CC1_SPEC,					\
 		       GNU_USER_TARGET_CC1_SPEC " " ASAN_CC1_SPEC " "	\
 		       ANDROID_CC1_SPEC)
 
diff --git a/gcc/config/arm/uclinuxfdpiceabi.h b/gcc/config/arm/uclinuxfdpiceabi.h
new file mode 100644
index 0000000..328adcb
--- /dev/null
+++ b/gcc/config/arm/uclinuxfdpiceabi.h
@@ -0,0 +1,54 @@
+/* Configuration file for ARM GNU/Linux FDPIC EABI targets.
+   Copyright (C) 2018,2019 Free Software Foundation, Inc.
+   Contributed by STMicroelectronics.
+
+   This file is part of GCC.
+
+   GCC is free software; you can redistribute it and/or modify it
+   under the terms of the GNU General Public License as published
+   by the Free Software Foundation; either version 3, or (at your
+   option) any later version.
+
+   GCC is distributed in the hope that it will be useful, but WITHOUT
+   ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+   or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
+   License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with GCC; see the file COPYING3.  If not see
+   <http://www.gnu.org/licenses/>.  */
+
+/* On uClibc EABI GNU/Linux, we want to force -mfdpic by default,
+   which also means we produce PIE code by default.  */
+#undef FDPIC_CC1_SPEC
+#define FDPIC_CC1_SPEC \
+  "%{!mno-fdpic:-mfdpic %{!fno-PIE:%{!fpie:%{!fPIC:%{!fpic: -fPIE}}}}}"
+
+/* Add --fdpic assembler flag by default.  */
+#undef TARGET_FDPIC_ASM_SPEC
+#define TARGET_FDPIC_ASM_SPEC "%{!mno-fdpic: --fdpic}"
+
+/* TARGET_BIG_ENDIAN_DEFAULT is set in
+   config.gcc for big endian configurations.  */
+#if TARGET_BIG_ENDIAN_DEFAULT
+#define TARGET_FDPIC_LINKER_EMULATION "armelfb_linux_fdpiceabi"
+#else
+#define TARGET_FDPIC_LINKER_EMULATION "armelf_linux_fdpiceabi"
+#endif
+
+/* Unless we generate a shared library or a relocatable object, we
+   force -pie.  */
+/* -static is not supported, because we have to define the
+   dynamic-linker, as we have some relocations to resolve at load
+   time. We do not generate an error in case the user explictly passes
+   the -dynamic-linker option to the linker.  */
+#undef  SUBTARGET_EXTRA_LINK_SPEC
+#define SUBTARGET_EXTRA_LINK_SPEC			    \
+  "%{!mno-fdpic: -m " TARGET_FDPIC_LINKER_EMULATION	    \
+   "%{!shared:%{!r: -pie}} }"				    \
+  "%{mno-fdpic: -m " TARGET_LINKER_EMULATION "}"	    \
+  "%{!r:%{!mno-fdpic: -z now}}"
+
+#undef	STARTFILE_SPEC
+#define STARTFILE_SPEC "%{!mno-fdpic:%{!shared:crtreloc.o%s}} " \
+  LINUX_OR_ANDROID_LD (GNU_USER_TARGET_STARTFILE_SPEC, ANDROID_STARTFILE_SPEC)
diff --git a/libsanitizer/configure.tgt b/libsanitizer/configure.tgt
index 3fb90ea..714f292 100644
--- a/libsanitizer/configure.tgt
+++ b/libsanitizer/configure.tgt
@@ -42,6 +42,9 @@ case "${target}" in
 	;;
   sparc*-*-solaris2.11*)
 	;;
+  arm*-*-*fdpiceabi)
+	UNSUPPORTED=1
+	;;
   arm*-*-linux*)
 	;;
   mips*64*-*-linux*)
-- 
2.6.3