Fix problem where -u is ignored when a weak undef is seen.

When the linker has a weak undefined symbol, it normally does not
select an archive library member just to satisfy the reference.
If the same symbol is also listed in a -u option, however, we
should select the archive library member.  This patch reorders
the code in Library_base::should_include_member so that the
additional checks are performed in the case of a weak undef.

gold/

2014-02-06  Cary Coutant  <ccoutant@google.com>

	* archive.cc (Library_base::should_include_member): Reorder
	code to check for -u option if a weak undef has already been seen.
	* testsuite/Makefile.am (weak_undef_test_2): New test case.
	* testsuite/Makefile.in: Regenerate.
	* testsuite/weak_undef_file3.cc: New file.
	* testsuite/weak_undef_file4.cc: New file.
	* testsuite/weak_undef_test_2.cc: New file.
Tweak in memory_error

This patch adds a local variable exception of type 'enum errors' and
pass it to throw_error, because 'err' is of type
'enum target_xfer_error', and we're abusing it to store an 'enum errors'.

gdb:

2014-02-07  Yao Qi  <yao@codesourcery.com>

	* corefile.c (memory_error): Get 'exception' from ERR and pass
	'exception' to throw_error.
core_xfer_shared_libraries and core_xfer_shared_libraries_aix returns ULONGEST

This patch documents the return value of core_xfer_shared_libraries_aix
and core_xfer_shared_libraries gdbarch methods, and changes return
type to ULONGEST from LONGEST.

In a following patch, core_xfer_partial. is changed to check their
return values and return an appropriate target_xfer_status.

gdb:

2014-02-07  Yao Qi  <yao@codesourcery.com>

	* gdbarch.sh (core_xfer_shared_libraries): Returns ULONGEST.  Add
	comments.
	(core_xfer_shared_libraries_aix): Likewise.
	* gdbarch.c, gdbarch.h: Regenerated.
	* i386-cygwin-tdep.c (windows_core_xfer_shared_libraries): Return
	ULONGEST.  Change 'len_avail' type to ULONGEST.
	* rs6000-aix-tdep.c (rs6000_aix_ld_info_to_xml): Likewise.
	* rs6000-aix-tdep.h (rs6000_aix_ld_info_to_xml): Update
	declaration.
	(rs6000_aix_core_xfer_shared_libraries_aix): Return ULONGEST.
Replace -1 with TARGET_XFER_E_IO

Hi,
This patch replaces -1 with TARGET_XFER_E_IO in the implementations of
to_xfer_partial and their callees.  This change is quite mechanical,
and makes the next patch shorter.

gdb:

2014-02-07  Yao Qi  <yao@codesourcery.com>

	* auxv.c (procfs_xfer_auxv): Replace -1 with TARGET_XFER_E_IO.
	(ld_so_xfer_auxv): Likewise.
	* bfd-target.c (target_bfd_xfer_partial): Likewise.
	* bsd-kvm.c (bsd_kvm_xfer_partial): Likewise.
	* corelow.c (core_xfer_partial): Likewise.
	* ctf.c (ctf_xfer_partial): Likewise.
	* darwin-nat.c (darwin_read_dyld_info): Likewise.
	(darwin_xfer_partial): Likewise.
	* exec.c (exec_xfer_partial): Likewise.
	* gnu-nat.c (gnu_xfer_partial): Likewise.
	* ia64-hpux-nat.c (ia64_hpux_xfer_uregs): Likewise.
	* inf-ptrace.c (inf_ptrace_xfer_partial): Likewise.
	* inf-ttrace.c (inf_ttrace_xfer_partial): Likewise.
	* linux-nat.c (linux_xfer_siginfo): Likewise.
	(linux_proc_xfer_spu): Likewise.
	* procfs.c (procfs_xfer_partial): Likewise.
	* record-full.c (record_full_xfer_partial): Likewise.
	(record_full_core_xfer_partial): Likewise.
	* remote-sim.c (gdbsim_xfer_partial): Likewise.
	* remote.c (remote_write_qxfer): Likewise.
	(remote_write_qxfer, remote_read_qxfer): Likewise.
	(remote_xfer_partial): Likewise.
	* rs6000-nat.c (rs6000_xfer_partial): Likewise.
	(rs6000_xfer_shared_libraries): Likewise.
	* sparc-nat.c (sparc_xfer_wcookie): Likewise.
	* spu-linux-nat.c (spu_proc_xfer_spu): Likewise.
	(spu_xfer_partial): Likewise.
	* target.c (memory_xfer_partial_1): Likewise.
	* tracepoint.c (tfile_xfer_partial): Likewise.
	* windows-nat.c (windows_xfer_shared_libraries): Likewise.
	(windows_xfer_partial): Likewise.
Return early in target_xfer_partial when LEN is zero.

Nowadays, argument LEN of to_xfer_partial can be zero in some cases,
and each implementation may do nothing and return zero, indicating
transfer is done.  That is fine.  However, when we change
to_xfer_partial to return target_xfer_status, we have to check every
return value of most of to_xfer_partial implementations, return
TARGET_XFER_DONE if return value is zero.

This patch simplifies this by checking LEN in target_xfer_partial, and
return 0 if LEN is zero.  Regression tested on x86_84-linux.  Is it
OK?

gdb:

2014-02-07  Yao Qi  <yao@codesourcery.com>

	* target.c (target_xfer_partial): Return zero if LEN is zero.