Three weeks to branching (gdb 7.5 release)
H.J. Lu
hjl.tools@gmail.com
Sun May 20 21:25:00 GMT 2012
On Sun, May 20, 2012 at 1:43 PM, Mark Kettenis <mark.kettenis@xs4all.nl> wrote:
>> Date: Sun, 20 May 2012 08:40:26 -0700
>> From: "H.J. Lu" <hjl.tools@gmail.com>
>>
>> On Fri, May 11, 2012 at 11:43 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
>> > On Fri, May 11, 2012 at 11:17 AM, Joel Brobecker <brobecker@adacore.com> wrote:
>> >> Hello,
>> >>
>> >> Just a quick heads up: The current tentative date for branching
>> >> GDB (7.5 release) is Mon Jun 4th, which is a little over three weeks
>> >> away.
>> >>
>> >> I've created a wiki page for known issues that need to be fixed
>> >> before then:
>> >>
>> >> http://sourceware.org/gdb/wiki/GDB_7.5_Release
>> >>
>> >> When you add an issue, please make sure you add a name so we know
>> >> who is coordinating the effort. If you don't know who can work
>> >> on it, please just post the issue here, and we'll try to find some
>> >> help.
>> >>
>> >> I only know of one issue, which is a noticeable performance degradation
>> >> that was reported a while ago:
>> >>
>> >
>> > I'd like to merge x32 into GDB 7.5. My x32 change is on hjl/x32/master
>> > branch at
>> >
>> > http://sourceware.org/git/?p=gdb.git;a=summary
>> >
>> > The current diff only has 864 lines. One patch:
>> >
>> > http://sourceware.org/ml/gdb-patches/2012-05/msg00097.html
>> >
>> > isn't reviewed yet. I will open a meta bug for x32 integration.
>> >
>>
>> I opened:
>>
>> http://sourceware.org/bugzilla/show_bug.cgi?id=14099
>>
>> Thanks for help from everyone. The full GDBserver x32 support
>> as well as partial GDB x32 support have been checked in. The
>> remaining patches are:
>>
>> http://sourceware.org/ml/gdb-patches/2012-04/msg00195.html
>> http://sourceware.org/ml/gdb-patches/2012-04/msg00191.html
>> http://sourceware.org/ml/gdb-patches/2012-05/msg00744.html
>> http://sourceware.org/ml/gdb-patches/2012-05/msg00531.html
>> http://sourceware.org/ml/gdb-patches/2012-05/msg00533.html
>> http://sourceware.org/ml/gdb-patches/2012-05/msg00489.html
>> http://sourceware.org/ml/gdb-patches/2012-05/msg00438.html
>> http://sourceware.org/ml/gdb-patches/2012-05/msg00097.html
>>
>> I would appreciate help to get them reviewed and approved.
>
> As I wrote before, I don't think adding lots if if-statements is the
> proper way to add a new ABI to GDB. The proper way is to do it like
> the diff below. In that diff, I'm not entirely confident that calling
> amd64_linux_init_abi() from amd64_x32_linux_init_abi() makes all that
> much sense. For example the amd64_linux_record_tdep stuff probably
> isn't right for the x32 ABI. But at least this will give us a
> starting point where we won't end up adding
>
> if (gdbarch_ptr_bit (gdbarch) == 32)
> {
> ...
> }
Please take a look at
http://sourceware.org/ml/gdb-patches/2012-04/msg00195.html
It doesn't add any (gdbarch_ptr_bit (gdbarch) == 32). It just changes
it to bits_per_word. I add one "gdbarch_ptr_bit (gdbarch) == 32" in
amd64_linux_sigtramp_start and I will remove them from
http://sourceware.org/ml/gdb-patches/2012-05/msg00744.html
> else
> {
> }
>
> blocks all over the place.
>
>
>
> Index: amd64-linux-tdep.c
> ===================================================================
> RCS file: /cvs/src/src/gdb/amd64-linux-tdep.c,v
> retrieving revision 1.50
> diff -u -p -r1.50 amd64-linux-tdep.c
> --- amd64-linux-tdep.c 12 May 2012 08:54:03 -0000 1.50
> +++ amd64-linux-tdep.c 20 May 2012 20:31:53 -0000
> @@ -1543,6 +1543,24 @@ amd64_linux_init_abi (struct gdbarch_inf
>
> tdep->i386_syscall_record = amd64_linux_syscall_record;
> }
> +
> +static void
> +amd64_x32_linux_init_abi(struct gdbarch_info info, struct gdbarch *gdbarch)
> +{
> + struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
> + const struct target_desc *tdesc = info.target_desc;
> +
> + amd64_linux_init_abi (info, gdbarch);
> + amd64_x32_init_abi (info, gdbarch);
> +
> + if (! tdesc_has_registers (tdesc))
> + tdesc = tdesc_amd64_linux;
I assume you meant tdesc_x32_linux here. The problem is
when we reach here, if (! tdesc_has_registers (tdesc)) will always
be false since tdep->tdesc has been set by amd64_linux_init_abi.
> + tdep->tdesc = tdesc;
> +
> + /* GNU/Linux uses SVR4-style shared libraries. */
> + set_solib_svr4_fetch_link_map_offsets
> + (gdbarch, svr4_ilp32_fetch_link_map_offsets);
> +}
>
>
> /* Provide a prototype to silence -Wmissing-prototypes. */
> @@ -1553,6 +1571,8 @@ _initialize_amd64_linux_tdep (void)
> {
> gdbarch_register_osabi (bfd_arch_i386, bfd_mach_x86_64,
> GDB_OSABI_LINUX, amd64_linux_init_abi);
> + gdbarch_register_osabi (bfd_arch_i386, bfd_mach_x64_32,
> + GDB_OSABI_LINUX, amd64_x32_linux_init_abi);
>
> /* Initialize the Linux target description. */
> initialize_tdesc_amd64_linux ();
> Index: amd64-tdep.c
> ===================================================================
> RCS file: /cvs/src/src/gdb/amd64-tdep.c,v
> retrieving revision 1.104
> diff -u -p -r1.104 amd64-tdep.c
> --- amd64-tdep.c 14 May 2012 18:56:40 -0000 1.104
> +++ amd64-tdep.c 20 May 2012 20:31:54 -0000
> @@ -258,7 +258,8 @@ static const char *amd64_word_names[] =
> static const char *amd64_dword_names[] =
> {
> "eax", "ebx", "ecx", "edx", "esi", "edi", "ebp", "esp",
> - "r8d", "r9d", "r10d", "r11d", "r12d", "r13d", "r14d", "r15d"
> + "r8d", "r9d", "r10d", "r11d", "r12d", "r13d", "r14d", "r15d",
> + "eip"
> };
>
> /* Return the name of register REGNUM. */
> @@ -2729,6 +2730,43 @@ amd64_init_abi (struct gdbarch_info info
> set_gdbarch_stap_parse_special_token (gdbarch,
> i386_stap_parse_special_token);
> }
> +
> +
> +static struct type *
> +amd64_x32_pseudo_register_type (struct gdbarch *gdbarch, int regnum)
> +{
> + struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
> +
> + switch (regnum - tdep->eax_regnum)
> + {
> + case AMD64_RBP_REGNUM: /* %ebp */
> + case AMD64_RSP_REGNUM: /* %esp */
> + return builtin_type (gdbarch)->builtin_data_ptr;
> + case AMD64_RIP_REGNUM: /* %eip */
> + return builtin_type (gdbarch)->builtin_func_ptr;
> + }
> +
> + return i386_pseudo_register_type (gdbarch, regnum);
> +}
> +
> +void
> +amd64_x32_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
> +{
> + struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
> + const struct target_desc *tdesc = info.target_desc;
> +
> + amd64_init_abi (info, gdbarch);
> +
> + if (! tdesc_has_registers (tdesc))
> + tdesc = tdesc_x32;
Again, " if (! tdesc_has_registers (tdesc))" will always false
since tdep->tdesc has been set in amd64_init_abi. How
do we solve it? My suggestion is to add a new function
which is similar to amd64_init_abi, but takes a new argument,
const struct target_desc *, as the default tdesc. Both
amd64_init_abi and amd64_x32_init_abi will call this
function. Will it work for you?
Thanks.
--
H.J.
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