[AArch64, ILP32] 2/6 More backend changes and support for small absolute and

[AArch64, ILP32] 2/6 More backend changes and support for small absolute and
small PIC addressing models

gcc/

	* config/aarch64/aarch64.c (POINTER_BYTES): New define.
	(aarch64_load_symref_appropriately): In the case of
	SYMBOL_SMALL_ABSOLUTE, use the mode of 'dest' instead of Pmode
	to generate new rtx; likewise to the case of SYMBOL_SMALL_GOT.
	(aarch64_expand_mov_immediate): In the case of SYMBOL_FORCE_TO_MEM,
	change to pass 'ptr_mode' to force_const_mem and zero-extend 'mem'
	if 'mode' doesn't equal to 'ptr_mode'.
	(aarch64_output_mi_thunk): Add an assertion on the alignment of
	'vcall_offset'; change to call aarch64_emit_move differently depending
	on whether 'Pmode' equals to 'ptr_mode' or not; use 'POINTER_BYTES'
	to calculate the upper bound of 'vcall_offset'.
	(aarch64_cannot_force_const_mem): Change to also return true if
	mode != ptr_mode.
	(aarch64_legitimize_reload_address): In the case of large
	displacements, add new local variable 'xmode' and an assertion
	based on it; change to use 'xmode' to generate the new rtx and
	reload.
	(aarch64_asm_trampoline_template): Change to generate the template
	differently depending on TARGET_ILP32 or not; change to use
	'POINTER_BYTES' in the argument passed to assemble_aligned_integer.
	(aarch64_trampoline_size): Removed.
	(aarch64_trampoline_init): Add new local constant 'tramp_code_sz'
	and replace immediate literals with it.  Change to use 'ptr_mode'
	instead of 'DImode' and call convert_memory_address if the mode
	of 'fnaddr' doesn't equal to 'ptr_mode'.
	(aarch64_elf_asm_constructor): Change to use assemble_aligned_integer
	to output symbol.
	(aarch64_elf_asm_destructor): Likewise.
	* config/aarch64/aarch64.h (TRAMPOLINE_SIZE): Change to be dependent
	on TARGET_ILP32 instead of aarch64_trampoline_size.
	* config/aarch64/aarch64.md (movsi_aarch64): Add new alternatives
	of 'mov' between WSP and W registers as well as 'adr' and 'adrp'.
	(loadwb_pair<GPI:mode>_<PTR:mode>): Rename to ...
	(loadwb_pair<GPI:mode>_<P:mode>): ... this.  Replace PTR with P.
	(storewb_pair<GPI:mode>_<PTR:mode>): Likewise; rename to ...
	(storewb_pair<GPI:mode>_<P:mode>): ... this.
	(add_losym): Change to 'define_expand' and call gen_add_losym_<mode>
	depending on the value of 'mode'.
	(add_losym_<mode>): New.
	(ldr_got_small_<mode>): New, based on ldr_got_small.
	(ldr_got_small): Remove.
	(ldr_got_small_sidi): New.
	* config/aarch64/iterators.md (P): New.
	(PTR): Change to 'ptr_mode' in the condition.

From-SVN: r201165