Re: Three weeks to branching (gdb 7.5 release)

Mark Kettenis
2012-05-20T20:44:09Z

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> 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)
{
...
}
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;
+ tdep->tdesc = tdesc;
+
+ /* GNU/Linux uses SVR4-style shared libraries. */
+ set_solib_svr4_fetch_link_map_offsets
+ (gdbarch, svr4_ilp32_fetch_link_map_offsets);
+}
\f

/* 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);
}
+\f
+
+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;
+ tdep->tdesc = tdesc;
+
+ tdep->num_dword_regs = 17;
+ set_tdesc_pseudo_register_type (gdbarch, amd64_x32_pseudo_register_type);
+
+ set_gdbarch_long_bit (gdbarch, 32);
+ set_gdbarch_ptr_bit (gdbarch, 32);
+}

/* Provide a prototype to silence -Wmissing-prototypes. */
void _initialize_amd64_tdep (void);
Index: amd64-tdep.h
===================================================================
RCS file: /cvs/src/src/gdb/amd64-tdep.h,v
retrieving revision 1.21
diff -u -p -r1.21 amd64-tdep.h
--- amd64-tdep.h 4 Jan 2012 08:16:56 -0000 1.21
+++ amd64-tdep.h 20 May 2012 20:31:54 -0000
@@ -80,6 +80,8 @@ extern void amd64_displaced_step_fixup (
struct regcache *regs);

extern void amd64_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch);
+extern void amd64_x32_init_abi (struct gdbarch_info info,
+ struct gdbarch *gdbarch);

/* Fill register REGNUM in REGCACHE with the appropriate
floating-point or SSE register value from *FXSAVE. If REGNUM is
Index: i386-tdep.h
===================================================================
RCS file: /cvs/src/src/gdb/i386-tdep.h,v
retrieving revision 1.78
diff -u -p -r1.78 i386-tdep.h
--- i386-tdep.h 27 Apr 2012 20:47:54 -0000 1.78
+++ i386-tdep.h 20 May 2012 20:31:57 -0000
@@ -309,6 +309,8 @@ extern int i386_ymm_regnum_p (struct gdb

extern const char *i386_pseudo_register_name (struct gdbarch *gdbarch,
int regnum);
+extern struct type *i386_pseudo_register_type (struct gdbarch *gdbarch,
+ int regnum);

extern void i386_pseudo_register_read_into_value (struct gdbarch *gdbarch,
struct regcache *regcache,