trad-frame cleanups

trad-frame cleanups

With the new member functions for struct trad_frame_saved_reg, there is no
need to invoke some of the set/get functions anymore.  This patch removes
those and adjusts all callers.

Even though the most natural initial state of a saved register value is
UNKNOWN, there are target backends relying on the previous initial state
of REALREG set to a register's own number. I noticed this in at least a
couple targets: aarch64 and riscv.

Because of that, I decided to keep the reset function that sets the set of
register values to REALREG. I can't exercise all the targets to make sure
the initial state change won't break things, hence why it is risky to change
the default.

Validated with --enable-targets=all on aarch64-linux Ubuntu 18.04/20.04.

gdb/ChangeLog

2021-01-19  Luis Machado  <luis.machado@linaro.org>

	* trad-frame.h (trad_frame_saved_reg) <set_value_bytes>: Allocate
	memory and save data.
	(trad_frame_set_value, trad_frame_set_realreg, trad_frame_set_addr)
	(trad_frame_set_unknown, trad_frame_set_value_bytes)
	(trad_frame_value_p, trad_frame_addr_p, trad_frame_realreg_p)
	(trad_frame_value_bytes_p): Remove.
	(trad_frame_reset_saved_regs): Adjust documentation.
	* trad-frame.c (trad_frame_alloc_saved_regs): Initialize via a
	constructor and reset the state of the registers.
	(trad_frame_value_p, trad_frame_addr_p, trad_frame_realreg_p)
	(trad_frame_value_bytes_p, trad_frame_set_value)
	(trad_frame_set_realreg, trad_frame_set_addr)
	(trad_frame_set_unknown, trad_frame_set_value_bytes): Remove.
	(trad_frame_set_reg_realreg): Update to call member function.
	(trad_frame_set_reg_addr, trad_frame_set_reg_value_bytes): Likewise.
	(trad_frame_get_prev_register): Likewise.

	* aarch64-tdep.c (aarch64_analyze_prologue)
	(aarch64_analyze_prologue_test, aarch64_make_prologue_cache_1)
	(aarch64_prologue_prev_register): Update to use member functions.
	* alpha-mdebug-tdep.c (alpha_mdebug_frame_unwind_cache): Likewise.
	* alpha-tdep.c (alpha_heuristic_frame_unwind_cache): Likewise.
	* arc-tdep.c (arc_print_frame_cache, arc_make_frame_cache): Likewise.
	* arm-tdep.c (arm_make_prologue_cache, arm_exidx_fill_cache)
	(arm_make_epilogue_frame_cache): Likewise.
	* avr-tdep.c (avr_frame_unwind_cache)
	(avr_frame_prev_register): Likewise.
	* cris-tdep.c (cris_scan_prologue): Likewise.
	* csky-tdep.c (csky_frame_unwind_cache): Likewise.
	* frv-tdep.c (frv_analyze_prologue): Likewise.
	* hppa-tdep.c (hppa_frame_cache, hppa_fallback_frame_cache): Likewise.
	* lm32-tdep.c (lm32_frame_cache): Likewise.
	* m32r-tdep.c (m32r_frame_unwind_cache): Likewise.
	* m68hc11-tdep.c (m68hc11_frame_unwind_cache): Likewise.
	* mips-tdep.c (set_reg_offset, mips_insn16_frame_cache)
	(mips_micro_frame_cache, mips_insn32_frame_cache): Likewise.
	(reset_saved_regs): Adjust to set realreg.
	* riscv-tdep.c (riscv_scan_prologue, riscv_frame_cache): Adjust to
	call member functions.
	* rs6000-tdep.c (rs6000_frame_cache, rs6000_epilogue_frame_cache)
	* s390-tdep.c (s390_prologue_frame_unwind_cache)
	(s390_backchain_frame_unwind_cache): Likewise.
	* score-tdep.c (score7_analyze_prologue)
	(score3_analyze_prologue, score_make_prologue_cache): Likewise.
	* sparc-netbsd-tdep.c (sparc32nbsd_sigcontext_saved_regs): Likewise.
	* sparc-sol2-tdep.c (sparc32_sol2_sigtramp_frame_cache): Likewise.
	* sparc64-netbsd-tdep.c (sparc64nbsd_sigcontext_saved_regs): Likewise.
	* sparc64-sol2-tdep.c (sparc64_sol2_sigtramp_frame_cache): Likewise.
	* tilegx-tdep.c (tilegx_analyze_prologue)
	(tilegx_frame_cache): Likewise.
	* v850-tdep.c (v850_frame_cache): Likewise.
	* vax-tdep.c (vax_frame_cache): Likewise.