2009-02-06 Pedro Alves <pedro@codesourcery.com>

	gdb/
	* target.h (enum target_object): Add new TARGET_OBJECT_SIGNAL_INFO.
	* infrun.c (siginfo_value_read, siginfo_value_write): New.
	(siginfo_value_funcs): New.
	(siginfo_make_value): New.
	(_initialize_infrun): Create the $_siginfo convenience variable.
	* gdbtypes.h (append_composite_type_field_aligned): Declare.
	* gdbtypes.c (append_composite_type_field): Rename to...
	(append_composite_type_field_aligned): ... this.  Add ALIGNMENT
	argument.  Handle it.
	(append_composite_type_field): Rewrite on top of
	append_composite_type_field_aligned.
	* value.h (internalvar_make_value): New typedef.
	(struct internalvar) <make_value>: New field.
	(create_internalvar_type_lazy): Declare.
	* value.c (create_internalvar): Clear make_value.
	(create_internalvar_type_lazy): New.
	(value_of_internalvar): If make_value is set use it.
	(preserve_values): Skip internal variables that don't have a
	value.
	* gdbarch.sh (get_siginfo_type): New.
	* gdbarch.h, gdbarch.c: Regenerate.

	* linux-tdep.h, linux-tdep.c: New.
	* amd64-linux-tdep.c: Include "linux-tdep.h".
	(amd64_linux_init_abi): Register linux_get_siginfo_type and
	linux_get_siginfo_mapper.
	* i386-linux-tdep.c: Include "linux-tdep.h".
	(i386_linux_init_abi): Register linux_get_siginfo_type and
	linux_get_siginfo_mapper.
	* arm-linux-tdep.c: Include "linux-tdep.h".
	(i386_linux_init_abi): Register linux_get_siginfo_type and
	linux_get_siginfo_mapper.

	* linux-nat.c (linux_xfer_siginfo): New.
	(linux_nat_xfer_partial): Handle TARGET_OBJECT_SIGNAL_INFO.
	* remote.c (PACKET_qXfer_siginfo_read)
	(PACKET_qXfer_siginfo_write): New.
	(feature remote_protocol_features): Add "qXfer:siginfo:read" and
	"qXfer:siginfo:write" features.
	(remote_xfer_partial): Handle TARGET_OBJECT_SIGNAL_INFO.
	(_initialize_remote): Add "set/show remote read-siginfo-object"
	and "set/show remote write-siginfo-object" commands.

	* Makefile.in (ALL_TARGET_OBS): Add linux-tdep.o.
	(HFILES_NO_SRCDIR): Add linux-tdep.h.
	(ALLDEPFILES): Add linux-tdep.c.

	* configure.tgt (arm*-*-linux* | arm*-*-uclinux*)
	(i[34567]86-*-linux*, x86_64-*-linux*): Add linux-tdep.o to
	gdb_target_obs.

2009-02-06  Pedro Alves  <pedro@codesourcery.com>

	gdb/gdbserver/
	* server.c (handle_query): Report qXfer:siginfo:read and
	qXfer:siginfo:write as supported and handle them.
	* target.h (struct target_ops) <qxfer_siginfo>: New field.
	* linux-low.c (linux_xfer_siginfo): New.
	(linux_target_ops): Set it.

2009-02-06  Pedro Alves  <pedro@codesourcery.com>

	gdb/doc/
	* gdb.texinfo (Signals): Document $_siginfo.
	(Convenience Variables): Mention $_siginfo.
	(Remote Configuration): Document qXfer:siginfo:read,
	qXfer:siginfo:write packets, and the read-siginfo-object,
	write-siginfo-object commands.

2009-02-06  Pedro Alves  <pedro@codesourcery.com>

	gdb/testsuite/
	* gdb.base/siginfo-obj.c, gdb.base/siginfo-obj.exp: New.

2 files changed, 109 insertions, 0 deletions

diff --git a/gdb/doc/ChangeLog b/gdb/doc/ChangeLog
index 473c6e3..0874a56 100644
--- a/gdb/doc/ChangeLog
+++ b/gdb/doc/ChangeLog
@@ -1,5 +1,13 @@
 2009-02-06  Pedro Alves  <pedro@codesourcery.com>
 
+	* gdb.texinfo (Signals): Document $_siginfo.
+	(Convenience Variables): Mention $_siginfo.
+	(Remote Configuration): Document qXfer:siginfo:read,
+	qXfer:siginfo:write packets, and the read-siginfo-object,
+	write-siginfo-object commands.
+
+2009-02-06  Pedro Alves  <pedro@codesourcery.com>
+
 	* gdbint.texinfo (Values): New chapter.
 
 2009-02-06  Tom Tromey  <tromey@redhat.com>
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index 354b888..9ba56a8 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -4472,6 +4472,55 @@ a result of the fatal signal once it saw the signal.  To prevent this,
 you can continue with @samp{signal 0}.  @xref{Signaling, ,Giving your
 Program a Signal}.
 
+@cindex extra signal information
+@anchor{extra signal information}
+
+On some targets, @value{GDBN} can inspect extra signal information
+associated with the intercepted signal, before it is actually
+delivered to the program being debugged.  This information is exported
+by the convenience variable @code{$_siginfo}, and consists of data
+that is passed by the kernel to the signal handler at the time of the
+receipt of a signal.  The data type of the information itself is
+target dependent.  You can see the data type using the @code{ptype
+$_siginfo} command.  On Unix systems, it typically corresponds to the
+standard @code{siginfo_t} type, as defined in the @file{signal.h}
+system header.
+
+Here's an example, on a @sc{gnu}/Linux system, printing the stray
+referenced address that raised a segmentation fault.
+
+@smallexample
+@group
+(@value{GDBP}) continue
+Program received signal SIGSEGV, Segmentation fault.
+0x0000000000400766 in main ()
+69        *(int *)p = 0;
+(@value{GDBP}) ptype $_siginfo
+type = struct @{
+    int si_signo;
+    int si_errno;
+    int si_code;
+    union @{
+        int _pad[28];
+        struct @{...@} _kill;
+        struct @{...@} _timer;
+        struct @{...@} _rt;
+        struct @{...@} _sigchld;
+        struct @{...@} _sigfault;
+        struct @{...@} _sigpoll;
+    @} _sifields;
+@}
+(@value{GDBP}) ptype $_siginfo._sifields._sigfault
+type = struct @{
+    void *si_addr;
+@}
+(@value{GDBP}) p $_siginfo._sifields._sigfault.si_addr
+$1 = (void *) 0x7ffff7ff7000
+@end group
+@end smallexample
+
+Depending on target support, @code{$_siginfo} may also be writable.
+
 @node Thread Stops
 @section Stopping and Starting Multi-thread Programs
 
@@ -7348,6 +7397,11 @@ to match the format in which the data was printed.
 @vindex $_exitcode@r{, convenience variable}
 The variable @code{$_exitcode} is automatically set to the exit code when
 the program being debugged terminates.
+
+@item $_siginfo
+@vindex $_siginfo@r{, convenience variable}
+The variable @code{$_siginfo} is bound to extra signal information
+inspection (@pxref{extra signal information}).
 @end table
 
 On HP-UX systems, if you refer to a function or variable name that
@@ -14307,6 +14361,14 @@ are:
 @tab @code{qXfer:spu:write}
 @tab @code{info spu}
 
+@item @code{read-siginfo-object}
+@tab @code{qXfer:siginfo:read}
+@tab @code{print $_siginfo}
+
+@item @code{write-siginfo-object}
+@tab @code{qXfer:siginfo:write}
+@tab @code{set $_siginfo}
+
 @item @code{get-thread-local-@*storage-address}
 @tab @code{qGetTLSAddr}
 @tab Displaying @code{__thread} variables
@@ -26879,6 +26941,16 @@ These are the currently defined stub features and their properties:
 @tab @samp{-}
 @tab Yes
 
+@item @samp{qXfer:siginfo:read}
+@tab No
+@tab @samp{-}
+@tab Yes
+
+@item @samp{qXfer:siginfo:write}
+@tab No
+@tab @samp{-}
+@tab Yes
+
 @item @samp{QNonStop}
 @tab No
 @tab @samp{-}
@@ -26939,6 +27011,14 @@ The remote stub understands the @samp{qXfer:spu:read} packet
 The remote stub understands the @samp{qXfer:spu:write} packet
 (@pxref{qXfer spu write}).
 
+@item qXfer:siginfo:read
+The remote stub understands the @samp{qXfer:siginfo:read} packet
+(@pxref{qXfer siginfo read}).
+
+@item qXfer:siginfo:write
+The remote stub understands the @samp{qXfer:siginfo:write} packet
+(@pxref{qXfer siginfo write}).
+
 @item QNonStop
 The remote stub understands the @samp{QNonStop} packet
 (@pxref{QNonStop}).
@@ -27097,6 +27177,16 @@ annex part of the generic @samp{qXfer} packet must be empty
 This packet is not probed by default; the remote stub must request it,
 by supplying an appropriate @samp{qSupported} response (@pxref{qSupported}).
 
+@item qXfer:siginfo:read::@var{offset},@var{length}
+@anchor{qXfer siginfo read}
+Read contents of the extra signal information on the target
+system.  The annex part of the generic @samp{qXfer} packet must be
+empty (@pxref{qXfer read}).
+
+This packet is not probed by default; the remote stub must request it,
+by supplying an appropriate @samp{qSupported} response
+(@pxref{qSupported}).
+
 @item qXfer:spu:read:@var{annex}:@var{offset},@var{length}
 @anchor{qXfer spu read}
 Read contents of an @code{spufs} file on the target system.  The
@@ -27149,6 +27239,7 @@ the stub, or that the object does not support reading.
 
 @item qXfer:@var{object}:write:@var{annex}:@var{offset}:@var{data}@dots{}
 @cindex write data into object, remote request
+@anchor{qXfer write}
 Write uninterpreted bytes into the target's special data area
 identified by the keyword @var{object}, starting at @var{offset} bytes
 into the data.  @var{data}@dots{} is the binary-encoded data
@@ -27161,6 +27252,16 @@ Here are the specific requests of this form defined so far.  All
 formats, listed below.
 
 @table @samp
+@item qXfer:siginfo:write::@var{offset}:@var{data}@dots{}
+@anchor{qXfer siginfo write}
+Write @var{data} to the extra signal information on the target system.
+The annex part of the generic @samp{qXfer} packet must be
+empty (@pxref{qXfer write}).
+
+This packet is not probed by default; the remote stub must request it,
+by supplying an appropriate @samp{qSupported} response
+(@pxref{qSupported}).
+
 @item qXfer:spu:write:@var{annex}:@var{offset}:@var{data}@dots{}
 @anchor{qXfer spu write}
 Write @var{data} to an @code{spufs} file on the target system.  The