configure.ac: Add --enable-secureplt.

configure.ac: Add --enable-secureplt.

	* configure.ac: Add --enable-secureplt.
	(HAVE_AS_REL16): Test for R_PPC_REL16 relocs.
	* config.in: Regenerate.
	* configure: Regenerate.
	* config.gcc (powerpc64-*-linux*, powerpc-*-linux*): Add
	rs6000/secureplt.h to tm_file when enable_secureplt.
	* doc/invoke.texi (msecure-plt, mbss-plt): Document.
	* doc/install.texi: Document --enable-targets and --enable-secureplt.
	Correct xrefs to "Using the GNU Compiler Collection (GCC)".
	* config/rs6000/secureplt.h: New file.
	* config/rs6000/sysv4.h (TARGET_SECURE_PLT): Define.
	(SUBTARGET_OVERRIDE_OPTIONS): Error if -msecure-plt given without
	assembler support.
	(CC1_SECURE_PLT_DEFAULT_SPEC): Define.
	(CC1_SPEC): Delete duplicate mno-sdata.  Invoke cc1_secure_plt_default.
	(SUBTARGET_EXTRA_SPECS): Add cc1_secure_plt_default.
	* config/rs6000/sysv4.opt (msecure-plt, bss-plt): Add options.
	* config/rs6000/rs6000.h (TARGET_SECURE_PLT): Define.
	* config/rs6000/rs6000.c (rs6000_emit_load_toc_table): Handle
	TARGET_SECURE_PLT got register load sequence.
	(rs6000_emit_prologue): Call rs6000_emit_load_toc_table when
	TARGET_SECURE_PLT.
	(rs6000_elf_declare_function_name): Don't emit toc address offset
	word when TARGET_SECURE_PLT.
	* config/rs6000/rs6000.md (elf_high, elf_low): Move past load_toc_*.
	(load_toc_v4_PIC_1) Enable for TARGET_SECURE_PLT.
	(load_toc_v4_PIC_3b, load_toc_v4_PIC_3c): New insns.
	(call, call_value): Mark pic_offset_table_rtx used for sysv pic and
	TARGET_SECURE_PLT.
	(call_nonlocal_sysv, call_value_nonlocal_sysv, sibcall_nonlocal_sysv,
	sibcall_value_nonlocal_sysv): Add 32768 offset when TARGET_SECURE_PLT
	and -fPIC.
	* config/rs6000/tramp.asm (trampoline_initial): Use "bcl 20,31".
	(__trampoline_setup): Likewise.  Init r30 before plt call.

From-SVN: r100415