[PATCH RFC] backends: Add RISC-V object attribute printing

[Andreas Schwab <schwab@suse.de>]

This does not work yet.  The RISC-V attribute tags use the same
convention as the GNU attributes: odd numbered tags take a string value,
even numbered ones an integer value, but print_attributes assumes the
ARM numbering scheme by default for non-GNU attributes.

---
 backends/ChangeLog     |  6 ++++
 backends/Makefile.am   |  3 +-
 backends/riscv_attrs.c | 80 ++++++++++++++++++++++++++++++++++++++++++
 backends/riscv_init.c  |  2 ++
 4 files changed, 90 insertions(+), 1 deletion(-)
 create mode 100644 backends/riscv_attrs.c

diff --git a/backends/ChangeLog b/backends/ChangeLog
index 5b0daffe..a642fe9e 100644
--- a/backends/ChangeLog
+++ b/backends/ChangeLog
@@ -1,3 +1,9 @@
+2022-08-10  Andreas Schwab  <schwab@suse.de>
+
+	* Makefile.am (riscv_SRCS): Add riscv_attrs.c.
+	* riscv_init.c (riscv_init): Hook in riscv_check_object_attribute.
+	* riscv_attrs.c: New file.
+
 2022-08-09  Andreas Schwab  <schwab@suse.de>
 
 	* riscv_init.c (riscv_init): HOOK segment_type_name,
diff --git a/backends/Makefile.am b/backends/Makefile.am
index 9566377f..1863f66a 100644
--- a/backends/Makefile.am
+++ b/backends/Makefile.am
@@ -91,7 +91,8 @@ m68k_corenote_no_Wpacked_not_aligned = yes
 bpf_SRCS = bpf_init.c bpf_regs.c bpf_symbol.c
 
 riscv_SRCS = riscv_init.c riscv_symbol.c riscv_cfi.c riscv_regs.c \
-	     riscv_initreg.c riscv_corenote.c riscv64_corenote.c riscv_retval.c
+	     riscv_initreg.c riscv_corenote.c riscv64_corenote.c \
+	     riscv_retval.c riscv_attrs.c
 
 csky_SRCS = csky_attrs.c csky_init.c csky_symbol.c csky_cfi.c \
 	    csky_regs.c csky_initreg.c csky_corenote.c
diff --git a/backends/riscv_attrs.c b/backends/riscv_attrs.c
new file mode 100644
index 00000000..6947be6e
--- /dev/null
+++ b/backends/riscv_attrs.c
@@ -0,0 +1,80 @@
+/* Object attribute tags for RISC-V.
+   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 <string.h>
+#include <dwarf.h>
+
+#define BACKEND riscv_
+#include "libebl_CPU.h"
+
+#define KNOWN_VALUES(...) do				\
+  {							\
+    static const char *table[] = { __VA_ARGS__ };	\
+    if (value < sizeof table / sizeof table[0])		\
+      *value_name = table[value];			\
+  } while (0)
+
+bool
+riscv_check_object_attribute (Ebl *ebl __attribute__ ((unused)),
+			      const char *vendor, int tag, uint64_t value,
+			      const char **tag_name, const char **value_name)
+{
+  if (!strcmp (vendor, "riscv"))
+    switch (tag)
+      {
+      case 4:
+	*tag_name = "RISCV_stack_align";
+	return true;
+
+      case 5:
+	*tag_name = "RISCV_arch";
+	return true;
+
+      case 6:
+	*tag_name = "RISCV_unaligned_access";
+	KNOWN_VALUES ("No unaligned access", "Unaligned access");
+	return true;
+
+      case 8:
+	*tag_name = "RISCV_priv_spec";
+	return true;
+
+      case 10:
+        *tag_name = "RISCV_priv_spec_minor";
+        return true;
+
+      case 12:
+        *tag_name = "RISCV_priv_spec_revision";
+        return true;
+      }
+
+  return false;
+}
diff --git a/backends/riscv_init.c b/backends/riscv_init.c
index f2d46082..e5e9e33e 100644
--- a/backends/riscv_init.c
+++ b/backends/riscv_init.c
@@ -69,6 +69,8 @@ riscv_init (Elf *elf,
   HOOK (eh, section_type_name);
   HOOK (eh, dynamic_tag_name);
   HOOK (eh, dynamic_tag_check);
+  HOOK (eh, check_object_attribute);
+  HOOK (eh, set_initial_registers_tid);
   if (eh->class == ELFCLASS64)
     eh->core_note = riscv64_core_note;
   else
-- 
2.37.1


-- 
Andreas Schwab, SUSE Labs, schwab@suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE  1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."