[RFC] backends: Add RISC-V object attribute printing
Commit Message
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
Comments
Hi Andreas,
On Wed, 2022-08-10 at 11:27 +0200, Andreas Schwab via Elfutils-devel
wrote:
> 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.
Yeah, I see this comment in print_attributes:
/* GNU style tags have either a uleb128 value,
when lowest bit is not set, or a string
when the lowest bit is set.
"compatibility" (32) is special. It has
both a string and a uleb128 value. For
non-gnu we assume 6 till 31 only take ints.
XXX see arm backend, do we need a separate
hook? */
Maybe we need a flag in the backend to tell whether attributes follow
the "gnu_vendor" convention? So that could be checked at:
bool gnu_vendor = (q - name == sizeof "gnu"
&& !memcmp (name, "gnu", sizeof "gnu"));
gnu_vendor |= ebl->has_gnu_attributes;
Or something similar?
Cheers,
Mark
On 10/13/22 16:53, Mark Wielaard wrote:
> Hi Andreas,
>
> On Wed, 2022-08-10 at 11:27 +0200, Andreas Schwab via Elfutils-devel
> wrote:
>> 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.
>
> Yeah, I see this comment in print_attributes:
>
> /* GNU style tags have either a uleb128 value,
> when lowest bit is not set, or a string
> when the lowest bit is set.
> "compatibility" (32) is special. It has
> both a string and a uleb128 value. For
> non-gnu we assume 6 till 31 only take ints.
> XXX see arm backend, do we need a separate
> hook? */
>
> Maybe we need a flag in the backend to tell whether attributes follow
> the "gnu_vendor" convention? So that could be checked at:
>
> bool gnu_vendor = (q - name == sizeof "gnu"
> && !memcmp (name, "gnu", sizeof "gnu"));
> gnu_vendor |= ebl->has_gnu_attributes;
>
> Or something similar?
Andreas: Can you please take a look at this?
Martin
>
> Cheers,
>
> Mark
Hi,
On Fri, Nov 25, 2022 at 05:29:19PM +0100, Martin Liška wrote:
> On 10/13/22 16:53, Mark Wielaard wrote:
> > On Wed, 2022-08-10 at 11:27 +0200, Andreas Schwab via Elfutils-devel
> > wrote:
> >> 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.
> >
> > Yeah, I see this comment in print_attributes:
> >
> > /* GNU style tags have either a uleb128 value,
> > when lowest bit is not set, or a string
> > when the lowest bit is set.
> > "compatibility" (32) is special. It has
> > both a string and a uleb128 value. For
> > non-gnu we assume 6 till 31 only take ints.
> > XXX see arm backend, do we need a separate
> > hook? */
> >
> > Maybe we need a flag in the backend to tell whether attributes follow
> > the "gnu_vendor" convention? So that could be checked at:
> >
> > bool gnu_vendor = (q - name == sizeof "gnu"
> > && !memcmp (name, "gnu", sizeof "gnu"));
> > gnu_vendor |= ebl->has_gnu_attributes;
> >
> > Or something similar?
>
> Andreas: Can you please take a look at this?
Has anybody had time to look at this?
Thanks,
Mark
@Andreas: Can you take a look?
Martin
On 2/22/23 23:56, Mark Wielaard wrote:
> Hi,
>
> On Fri, Nov 25, 2022 at 05:29:19PM +0100, Martin Liška wrote:
>> On 10/13/22 16:53, Mark Wielaard wrote:
>>> On Wed, 2022-08-10 at 11:27 +0200, Andreas Schwab via Elfutils-devel
>>> wrote:
>>>> 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.
>>>
>>> Yeah, I see this comment in print_attributes:
>>>
>>> /* GNU style tags have either a uleb128 value,
>>> when lowest bit is not set, or a string
>>> when the lowest bit is set.
>>> "compatibility" (32) is special. It has
>>> both a string and a uleb128 value. For
>>> non-gnu we assume 6 till 31 only take ints.
>>> XXX see arm backend, do we need a separate
>>> hook? */
>>>
>>> Maybe we need a flag in the backend to tell whether attributes follow
>>> the "gnu_vendor" convention? So that could be checked at:
>>>
>>> bool gnu_vendor = (q - name == sizeof "gnu"
>>> && !memcmp (name, "gnu", sizeof "gnu"));
>>> gnu_vendor |= ebl->has_gnu_attributes;
>>>
>>> Or something similar?
>>
>> Andreas: Can you please take a look at this?
>
> Has anybody had time to look at this?
>
> Thanks,
>
> Mark
@@ -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,
@@ -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
new file mode 100644
@@ -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;
+}
@@ -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