aarch64: Add support for aarch64-sys-regs.def

This patch defines the structure of a new .def file used for
representing the aarch64 system registers, what information it should
hold and the basic framework in GCC to process this file.

Entries in the aarch64-system-regs.def file should be as follows:

  SYSREG (NAME, CPENC (sn,op1,cn,cm,op2), FLAG1 | ... | FLAGn, ARCH)

Where the arguments to SYSREG correspond to:
  - NAME:  The system register name, as used in the assembly language.
  - CPENC: The system register encoding, mapping to:

    	       s<sn>_<op1>_c<cn>_c<cm>_<op2>

  - FLAG: The entries in the FLAGS field are bitwise-OR'd together to
    	  encode extra information required to ensure proper use of
	  the system register.  For example, a read-only system
	  register will have the flag F_REG_READ, while write-only
	  registers will be labeled F_REG_WRITE.  Such flags are
	  tested against at compile-time.
  - ARCH: The architectural features the system register is associated
    	  with.  This is encoded via one of three possible macros:
	  1. When a system register is universally implemented, we say
	  it has no feature requirements, so we tag it with the
	  AARCH64_NO_FEATURES macro.
	  2. When a register is only implemented for a single
	  architectural extension EXT, the AARCH64_FEATURE (EXT), is
	  used.
	  3. When a given system register is made available by any of N
	  possible architectural extensions, the AARCH64_FEATURES(N, ...)
	  macro is used to combine them accordingly.

In order to enable proper interpretation of the SYSREG entries by the
compiler, flags defining system register behavior such as `F_REG_READ'
and `F_REG_WRITE' are also defined here, so they can later be used for
the validation of system register properties.

Finally, any architectural feature flags from Binutils missing from GCC
have appropriate aliases defined here so as to ensure
cross-compatibility of SYSREG entries across the toolchain.

gcc/ChangeLog:

	* config/aarch64/aarch64.cc (sysreg_t): New.
	(aarch64_sysregs): Likewise.
	(AARCH64_FEATURE): Likewise.
	(AARCH64_FEATURES): Likewise.
	(AARCH64_NO_FEATURES): Likewise.
	* config/aarch64/aarch64.h (AARCH64_ISA_V8A): Add missing
	ISA flag.
	(AARCH64_ISA_V8_1A): Likewise.
	(AARCH64_ISA_V8_7A): Likewise.
	(AARCH64_ISA_V8_8A): Likewise.
	(AARCH64_NO_FEATURES): Likewise.
	(AARCH64_FL_RAS): New ISA flag alias.
	(AARCH64_FL_LOR): Likewise.
	(AARCH64_FL_PAN): Likewise.
	(AARCH64_FL_AMU): Likewise.
	(AARCH64_FL_SCXTNUM): Likewise.
	(AARCH64_FL_ID_PFR2): Likewise.
	(F_DEPRECATED): New.
	(F_REG_READ): Likewise.
	(F_REG_WRITE): Likewise.
	(F_ARCHEXT): Likewise.
	(F_REG_ALIAS): Likewise.

0 files changed, 0 insertions, 0 deletions