Add support for RISC-V

This implements initial support for the RISC-V architecture.  It has
been tested with qemu linux-user emulation
<https://build.opensuse.org/package/live_build_log/openSUSE:Factory:RISCV/elfutils/standard/riscv64>,
with the following unresolved issues

FAIL: run-strip-strmerge.sh
===========================

elflint /home/abuild/rpmbuild/BUILD/elfutils-0.170/tests/elfstrmerge
section [32] '.symtab': _GLOBAL_OFFSET_TABLE_ symbol value 0x51c0 does not match .got section address 0x5010
section [32] '.symtab': symbol 119: st_value out of bounds
FAIL run-strip-strmerge.sh (exit status: 1)

FAIL: run-elflint-self.sh
=========================

section [33] '.symtab': _GLOBAL_OFFSET_TABLE_ symbol value 0x6220 does not match .got section address 0x6008
section [33] '.symtab': symbol 135: st_value out of bounds
*** failure in /home/abuild/rpmbuild/BUILD/elfutils-0.170/src/elflint --quiet --gnu-ld /home/abuild/rpmbuild/BUILD/elfutils-0.170/src/addr2line
section [33] '.symtab': _GLOBAL_OFFSET_TABLE_ symbol value 0x91d8 does not match .got section address 0x9040
section [33] '.symtab': symbol 163: st_value out of bounds
*** failure in /home/abuild/rpmbuild/BUILD/elfutils-0.170/src/elflint --quiet --gnu-ld /home/abuild/rpmbuild/BUILD/elfutils-0.170/src/elfcmp
section [33] '.symtab': _GLOBAL_OFFSET_TABLE_ symbol value 0x1a2a0 does not match .got section address 0x1a040
section [33] '.symtab': symbol 267: st_value out of bounds
*** failure in /home/abuild/rpmbuild/BUILD/elfutils-0.170/src/elflint --quiet --gnu-ld /home/abuild/rpmbuild/BUILD/elfutils-0.170/src/elflint
section [33] '.symtab': _GLOBAL_OFFSET_TABLE_ symbol value 0xd418 does not match .got section address 0xd0f0
section [33] '.symtab': symbol 238: st_value out of bounds
*** failure in /home/abuild/rpmbuild/BUILD/elfutils-0.170/src/elflint --quiet --gnu-ld /home/abuild/rpmbuild/BUILD/elfutils-0.170/src/nm
section [33] '.symtab': _GLOBAL_OFFSET_TABLE_ symbol value 0xa2d0 does not match .got section address 0xa0b0
section [33] '.symtab': symbol 193: st_value out of bounds
*** failure in /home/abuild/rpmbuild/BUILD/elfutils-0.170/src/elflint --quiet --gnu-ld /home/abuild/rpmbuild/BUILD/elfutils-0.170/src/objdump
section [33] '.symtab': _GLOBAL_OFFSET_TABLE_ symbol value 0x2e5b8 does not match .got section address 0x2e058
section [33] '.symtab': symbol 410: st_value out of bounds
*** failure in /home/abuild/rpmbuild/BUILD/elfutils-0.170/src/elflint --quiet --gnu-ld /home/abuild/rpmbuild/BUILD/elfutils-0.170/src/readelf
section [32] '.symtab': _GLOBAL_OFFSET_TABLE_ symbol value 0x171b8 does not match .got section address 0x17010
*** failure in /home/abuild/rpmbuild/BUILD/elfutils-0.170/src/elflint --quiet --gnu-ld /home/abuild/rpmbuild/BUILD/elfutils-0.170/libelf/libelf.so
section [32] '.symtab': _GLOBAL_OFFSET_TABLE_ symbol value 0x3a5b0 does not match .got section address 0x3a0d8
*** failure in /home/abuild/rpmbuild/BUILD/elfutils-0.170/src/elflint --quiet --gnu-ld /home/abuild/rpmbuild/BUILD/elfutils-0.170/libdw/libdw.so
section [31] '.symtab': _GLOBAL_OFFSET_TABLE_ symbol value 0xd0c8 does not match .got section address 0xd008
*** failure in /home/abuild/rpmbuild/BUILD/elfutils-0.170/src/elflint --quiet --gnu-ld /home/abuild/rpmbuild/BUILD/elfutils-0.170/backends/libebl_i386.so
section [31] '.symtab': _GLOBAL_OFFSET_TABLE_ symbol value 0xf0c8 does not match .got section address 0xf008
*** failure in /home/abuild/rpmbuild/BUILD/elfutils-0.170/src/elflint --quiet --gnu-ld /home/abuild/rpmbuild/BUILD/elfutils-0.170/backends/libebl_x86_64.so
FAIL run-elflint-self.sh (exit status: 1)

FAIL: run-native-test.sh
========================

/home/abuild/rpmbuild/BUILD/elfutils-0.170/tests/allregs: dwfl_module_register_names: no backend registers known
FAIL run-native-test.sh (exit status: 1)

FAIL: run-backtrace-native-core.sh
==================================

backtrace: backtrace.c:111: callback_verify: Assertion `symname && strcmp (symname, "raise") == 0' failed.
./test-subr.sh: line 84: 26040 Aborted                 (core dumped) LD_LIBRARY_PATH="${built_library_path}${LD_LIBRARY_PATH:+:}$LD_LIBRARY_PATH" $VALGRIND_CMD "$@"
backtrace-child-core.26027: no main
rmdir: failed to remove 'test-26016': Directory not empty
FAIL run-backtrace-native-core.sh (exit status: 1)

In addition, all tests that use ptrace are failing as linux-user
emulation does not implement it.

There are no regressions for a x86_64 build.

Signed-off-by: Andreas Schwab <schwab@suse.de>

5 files changed, 215 insertions, 2 deletions

diff --git a/backends/ChangeLog b/backends/ChangeLog
index 57baea09..63bb7e44 100644
--- a/backends/ChangeLog
+++ b/backends/ChangeLog
@@ -1,3 +1,10 @@
+2018-04-19  Andreas Schwab  <schwab@suse.de>
+
+	* Makefile.am (modules): Add riscv.
+	* riscv_init.c: New file.
+	* riscv_reloc.def: New file.
+	* riscv_symbol.c: New file.
+
 2018-04-11  Mark Wielaard  <mark@klomp.org>
 
 	* aarch64_cfi.c (aarch64_abi_cfi): Add rule for restoring SP from
diff --git a/backends/Makefile.am b/backends/Makefile.am
index 2c62add2..80aa00e7 100644
--- a/backends/Makefile.am
+++ b/backends/Makefile.am
@@ -33,12 +33,12 @@ AM_CPPFLAGS += -I$(top_srcdir)/libebl -I$(top_srcdir)/libasm \
 
 
 modules = i386 sh x86_64 ia64 alpha arm aarch64 sparc ppc ppc64 s390 \
-	  tilegx m68k bpf
+	  tilegx m68k bpf riscv
 libebl_pic = libebl_i386_pic.a libebl_sh_pic.a libebl_x86_64_pic.a    \
 	     libebl_ia64_pic.a libebl_alpha_pic.a libebl_arm_pic.a    \
 	     libebl_aarch64_pic.a libebl_sparc_pic.a libebl_ppc_pic.a \
 	     libebl_ppc64_pic.a libebl_s390_pic.a libebl_tilegx_pic.a \
-	     libebl_m68k_pic.a libebl_bpf_pic.a
+	     libebl_m68k_pic.a libebl_bpf_pic.a libebl_riscv_pic.a
 noinst_LIBRARIES = $(libebl_pic)
 noinst_DATA = $(libebl_pic:_pic.a=.so)
 
@@ -131,6 +131,10 @@ cpu_bpf = ../libcpu/libcpu_bpf.a
 libebl_bpf_pic_a_SOURCES = $(bpf_SRCS)
 am_libebl_bpf_pic_a_OBJECTS = $(bpf_SRCS:.c=.os)
 
+riscv_SRCS = riscv_init.c riscv_symbol.c
+libebl_riscv_pic_a_SOURCES = $(riscv_SRCS)
+am_libebl_riscv_pic_a_OBJECTS = $(riscv_SRCS:.c=.os)
+
 
 libebl_%.so libebl_%.map: libebl_%_pic.a $(libelf) $(libdw) $(libeu)
 	@rm -f $(@:.so=.map)
diff --git a/backends/riscv_init.c b/backends/riscv_init.c
new file mode 100644
index 00000000..761d9c2e
--- /dev/null
+++ b/backends/riscv_init.c
@@ -0,0 +1,57 @@
+/* Initialization of RISC-V specific backend library.
+   This file is part of elfutils.
+
+   This file is free software; you can redistribute it and/or modify
+   it under the terms of either
+
+     * the GNU Lesser General Public License as published by the Free
+       Software Foundation; either version 3 of the License, or (at
+       your option) any later version
+
+   or
+
+     * the GNU General Public License as published by the Free
+       Software Foundation; either version 2 of the License, or (at
+       your option) any later version
+
+   or both in parallel, as here.
+
+   elfutils 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 copies of the GNU General Public License and
+   the GNU Lesser General Public License along with this program.  If
+   not, see <http://www.gnu.org/licenses/>.  */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#define BACKEND		riscv_
+#define RELOC_PREFIX	R_RISCV_
+#include "libebl_CPU.h"
+
+/* This defines the common reloc hooks based on riscv_reloc.def.  */
+#include "common-reloc.c"
+
+
+const char *
+riscv_init (Elf *elf __attribute__ ((unused)),
+	    GElf_Half machine __attribute__ ((unused)),
+	    Ebl *eh,
+	    size_t ehlen)
+{
+  /* Check whether the Elf_BH object has a sufficent size.  */
+  if (ehlen < sizeof (Ebl))
+    return NULL;
+
+  /* We handle it.  */
+  eh->name = "RISC-V";
+  riscv_init_reloc (eh);
+  HOOK (eh, reloc_simple_type);
+  HOOK (eh, machine_flag_check);
+
+  return MODVERSION;
+}
diff --git a/backends/riscv_reloc.def b/backends/riscv_reloc.def
new file mode 100644
index 00000000..2bd3513e
--- /dev/null
+++ b/backends/riscv_reloc.def
@@ -0,0 +1,83 @@
+/* List the relocation types for RISC-V.  -*- C -*-
+   This file is part of elfutils.
+
+   This file is free software; you can redistribute it and/or modify
+   it under the terms of either
+
+     * the GNU Lesser General Public License as published by the Free
+       Software Foundation; either version 3 of the License, or (at
+       your option) any later version
+
+   or
+
+     * the GNU General Public License as published by the Free
+       Software Foundation; either version 2 of the License, or (at
+       your option) any later version
+
+   or both in parallel, as here.
+
+   elfutils 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 copies of the GNU General Public License and
+   the GNU Lesser General Public License along with this program.  If
+   not, see <http://www.gnu.org/licenses/>.  */
+
+/*	    NAME,		REL|EXEC|DYN	*/
+
+RELOC_TYPE (NONE,		EXEC|DYN)
+RELOC_TYPE (32,			REL|EXEC|DYN)
+RELOC_TYPE (64,			REL|EXEC|DYN)
+RELOC_TYPE (RELATIVE,		EXEC|DYN)
+RELOC_TYPE (COPY,		EXEC|DYN)
+RELOC_TYPE (JUMP_SLOT,		EXEC|DYN)
+RELOC_TYPE (TLS_DTPMOD32,	EXEC|DYN)
+RELOC_TYPE (TLS_DTPMOD64,	EXEC|DYN)
+RELOC_TYPE (TLS_DTPREL32,	EXEC|DYN)
+RELOC_TYPE (TLS_DTPREL64,	EXEC|DYN)
+RELOC_TYPE (TLS_TPREL32,	EXEC|DYN)
+RELOC_TYPE (TLS_TPREL64,	EXEC|DYN)
+RELOC_TYPE (BRANCH,		REL)
+RELOC_TYPE (JAL,		REL)
+RELOC_TYPE (CALL,		REL)
+RELOC_TYPE (CALL_PLT,		REL)
+RELOC_TYPE (GOT_HI20,		REL)
+RELOC_TYPE (TLS_GOT_HI20,	REL)
+RELOC_TYPE (TLS_GD_HI20,	REL)
+RELOC_TYPE (PCREL_HI20,		REL)
+RELOC_TYPE (PCREL_LO12_I,	REL)
+RELOC_TYPE (PCREL_LO12_S,	REL)
+RELOC_TYPE (HI20,		REL)
+RELOC_TYPE (LO12_I,		REL)
+RELOC_TYPE (LO12_S,		REL)
+RELOC_TYPE (TPREL_HI20,		REL)
+RELOC_TYPE (TPREL_LO12_I,	REL)
+RELOC_TYPE (TPREL_LO12_S,	REL)
+RELOC_TYPE (TPREL_ADD,		REL)
+RELOC_TYPE (ADD8,		REL)
+RELOC_TYPE (ADD16,		REL)
+RELOC_TYPE (ADD32,		REL)
+RELOC_TYPE (ADD64,		REL)
+RELOC_TYPE (SUB8,		REL)
+RELOC_TYPE (SUB16,		REL)
+RELOC_TYPE (SUB32,		REL)
+RELOC_TYPE (SUB64,		REL)
+RELOC_TYPE (GNU_VTINHERIT,	REL)
+RELOC_TYPE (GNU_VTENTRY,	REL)
+RELOC_TYPE (ALIGN,		REL)
+RELOC_TYPE (RVC_BRANCH,		REL)
+RELOC_TYPE (RVC_JUMP,		REL)
+RELOC_TYPE (RVC_LUI,		REL)
+RELOC_TYPE (GPREL_I,		REL)
+RELOC_TYPE (GPREL_S,		REL)
+RELOC_TYPE (TPREL_I,		REL)
+RELOC_TYPE (TPREL_S,		REL)
+RELOC_TYPE (RELAX,		REL)
+RELOC_TYPE (SUB6,		REL)
+RELOC_TYPE (SET6,		REL)
+RELOC_TYPE (SET8,		REL)
+RELOC_TYPE (SET16,		REL)
+RELOC_TYPE (SET32,		REL)
+RELOC_TYPE (32_PCREL,		REL)
diff --git a/backends/riscv_symbol.c b/backends/riscv_symbol.c
new file mode 100644
index 00000000..628e0572
--- /dev/null
+++ b/backends/riscv_symbol.c
@@ -0,0 +1,62 @@
+/* RISC-V specific symbolic name handling.
+   This file is part of elfutils.
+
+   This file is free software; you can redistribute it and/or modify
+   it under the terms of either
+
+     * the GNU Lesser General Public License as published by the Free
+       Software Foundation; either version 3 of the License, or (at
+       your option) any later version
+
+   or
+
+     * the GNU General Public License as published by the Free
+       Software Foundation; either version 2 of the License, or (at
+       your option) any later version
+
+   or both in parallel, as here.
+
+   elfutils 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 copies of the GNU General Public License and
+   the GNU Lesser General Public License along with this program.  If
+   not, see <http://www.gnu.org/licenses/>.  */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include <assert.h>
+#include <elf.h>
+#include <stddef.h>
+#include <string.h>
+
+#define BACKEND riscv_
+#include "libebl_CPU.h"
+
+
+/* Check for the simple reloc types.  */
+Elf_Type
+riscv_reloc_simple_type (Ebl *ebl __attribute__ ((unused)), int type)
+{
+  switch (type)
+    {
+    case R_RISCV_32:
+      return ELF_T_WORD;
+    case R_RISCV_64:
+      return ELF_T_XWORD;
+    default:
+      return ELF_T_NUM;
+    }
+}
+
+/* Check whether machine flags are valid.  */
+bool
+riscv_machine_flag_check (GElf_Word flags)
+{
+  return ((flags &~ (EF_RISCV_RVC
+		     | EF_RISCV_FLOAT_ABI)) == 0);
+}