[PowerPC] Consolidate linux target description selection

[PowerPC] Consolidate linux target description selection

Share target description declarations and selection among ppc linux
native targets, core files, gdbserver and IPA.

To avoid complicated define guards, gdbserver and IPA now have
declarations for all descriptions, including 64-bit generated
descriptions when compiled in 32-bit mode. These have always been
linked into the gdbserver and IPA binaries. Because they might be
uninitialized, the selection function checks that the selected
description is initialized.

gdb/ChangeLog:
2018-05-22  Pedro Franco de Carvalho  <pedromfc@linux.vnet.ibm.com>

	* arch/ppc-linux-common.c: New file.
	* arch/ppc-linux-common.h: New file.
	* arch/ppc-linux-tdesc.h: New file.
	* configure.tgt (powerpc*-*-linux*): Add arch/ppc-linux-common.o.
	* Makefile.in (ALL_TARGET_OBS): Add arch/ppc-linux-common.o.
	(HFILES_NO_SRCDIR): Add arch/ppc-linux-common.h and
	arch/ppc-linux-tdesc.h.
	* ppc-linux-nat.c: Include arch/ppc-linux-common.h and
	arch/ppc-linux-tdesc.h.
	(ppc_linux_nat_target::read_description): Remove target
	description matching code. Fill a ppc_linux_features struct and
	call ppc_linux_match_description with it. Move comment about ISA
	2.05 to ppc-linux-common.c.
	* ppc-linux-tdep.c: Include arch/ppc-linux-common.h and
	arch/ppc-linux-tdesc.h.
	(ppc_linux_core_read_description): Remove target description
	matching code. Fill a ppc_linux_features struct and call
	ppc_linux_match_description with it.
	* ppc-linux-tdep.h (tdesc_powerpc_32l, tdesc_powerpc_64l)
	(tdesc_powerpc_altivec32l, tdesc_powerpc_altivec64l)
	(tdesc_powerpc_cell32l, tdesc_powerpc_cell64l)
	(tdesc_powerpc_vsx32l, tdesc_powerpc_vsx64l)
	(tdesc_powerpc_isa205_32l, tdesc_powerpc_isa205_64l)
	(tdesc_powerpc_isa205_altivec32l, tdesc_powerpc_isa205_altivec64l)
	(tdesc_powerpc_isa205_vsx32l, tdesc_powerpc_isa205_vsx64l)
	(tdesc_powerpc_e500l): Remove.

gdb/gdbserver/ChangeLog:
2018-05-22  Pedro Franco de Carvalho  <pedromfc@linux.vnet.ibm.com>

	* configure.srv (srv_tgtobj): Add arch/ppc-linux-common.o.
	* Makefile.in (SFILES): Add arch/ppc-linux-common.c.
	* linux-ppc-tdesc.h: Rename to linux-ppc-tdesc-init.h.
	* linux-ppc-tdesc-init.h (tdesc_powerpc_32l, tdesc_powerpc_64l)
	(tdesc_powerpc_altivec32l, tdesc_powerpc_altivec64l)
	(tdesc_powerpc_cell32l, tdesc_powerpc_cell64l)
	(tdesc_powerpc_vsx32l, tdesc_powerpc_vsx64l)
	(tdesc_powerpc_isa205_32l, tdesc_powerpc_isa205_64l)
	(tdesc_powerpc_isa205_altivec32l, tdesc_powerpc_isa205_altivec64l)
	(tdesc_powerpc_isa205_vsx32l, tdesc_powerpc_isa205_vsx64l)
	(tdesc_powerpc_e500l): Remove.
	* linux-ppc-ipa.c: Include arch/ppc-linux-tdesc.h and
	linux-ppc-tdesc-init.h. Don't include linux-ppc-tdesc.h.
	* linux-ppc-low.c: Include arch/ppc-linux-common.h,
	arch/ppc-linux-tdesc.h, and linux-ppc-tdesc-init.h. Don't include
	linux-ppc-tdesc.h.
	(ppc_arch_setup): Remove target description matching code. Fill a
	ppc_linux_features struct and call ppc_linux_match_description
	with it.