Victor Do Nascimento <victor.donascime...@arm.com> writes:
> 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.
> (sysreg_structs): Likewise.
> (nsysreg): 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.
> ---
> gcc/config/aarch64/aarch64.cc | 53 +++++++++++++++++++++++++++++++++++
> gcc/config/aarch64/aarch64.h | 22 +++++++++++++++
> 2 files changed, 75 insertions(+)
>
> diff --git a/gcc/config/aarch64/aarch64.cc b/gcc/config/aarch64/aarch64.cc
> index 5fd7063663c..a4a9e2e51ea 100644
> --- a/gcc/config/aarch64/aarch64.cc
> +++ b/gcc/config/aarch64/aarch64.cc
> @@ -2806,6 +2806,59 @@ static const struct processor all_cores[] =
> feature_deps::V8A ().enable, &generic_tunings},
> {NULL, aarch64_none, aarch64_none, aarch64_no_arch, 0, NULL}
> };
> +/* Internal representation of system registers. */
> +typedef struct {
> + const char *name;
> + /* Stringified sysreg encoding values, represented as
> + s<sn>_<op1>_c<cn>_c<cm>_<op2>. */
> + const char *encoding;
> + /* Flags affecting sysreg usage, such as read/write-only. */
> + unsigned properties;
> + /* Architectural features implied by sysreg. */
> + aarch64_feature_flags arch_reqs;
> +} sysreg_t;
> +
> +/* An aarch64_feature_set initializer for a single feature,
> + AARCH64_FEATURE_<FEAT>. */
> +#define AARCH64_FEATURE(FEAT) AARCH64_FL_##FEAT
> +
> +/* Used by AARCH64_FEATURES. */
> +#define AARCH64_OR_FEATURES_1(X, F1) \
> + AARCH64_FEATURE (F1)
> +#define AARCH64_OR_FEATURES_2(X, F1, F2) \
> + (AARCH64_FEATURE (F1) | AARCH64_OR_FEATURES_1 (X, F2))
> +#define AARCH64_OR_FEATURES_3(X, F1, ...) \
> + (AARCH64_FEATURE (F1) | AARCH64_OR_FEATURES_2 (X, __VA_ARGS__))
> +
> +/* An aarch64_feature_set initializer for the N features listed in "...". */
> +#define AARCH64_FEATURES(N, ...) \
> + AARCH64_OR_FEATURES_##N (0, __VA_ARGS__)
> +
> +#define AARCH64_NO_FEATURES 0
> +
> +/* Flags associated with the properties of system registers. It mainly
> serves
> + to mark particular registers as read or write only. */
> +#define F_DEPRECATED (1 << 1)
> +#define F_REG_READ (1 << 2)
> +#define F_REG_WRITE (1 << 3)
> +#define F_ARCHEXT (1 << 4)
> +/* Flag indicating register name is alias for another system register. */
> +#define F_REG_ALIAS (1 << 5)
> +
> +/* Database of system registers, their encodings and architectural
> + requirements. */
> +const sysreg_t sysreg_structs[] =
How about "aarch64_sysregs" instead, to keep the CPU prefix?
> +{
> +#define CPENC(SN, OP1, CN, CM, OP2) "s"#SN"_"#OP1"_c"#CN"_c"#CM"_"#OP2
> +#define SYSREG(NAME, ENC, FLAGS, ARCH) \
> + { NAME, ENC, FLAGS, ARCH },
> +#include "aarch64-sys-regs.def"
> +#undef CPENC
> +};
> +
> +#undef AARCH64_NO_FEATURES
> +
> +const unsigned nsysreg = ARRAY_SIZE (sysreg_structs);
I think it's clearer to drop this and instead use ARRAY_SIZE directly.
OK with those changes, thanks -- no need to repost unless you want to.
Richard
>
> /* The current tuning set. */
> struct tune_params aarch64_tune_params = generic_tunings;
> diff --git a/gcc/config/aarch64/aarch64.h b/gcc/config/aarch64/aarch64.h
> index 2f0777a37ac..84e6f79ca83 100644
> --- a/gcc/config/aarch64/aarch64.h
> +++ b/gcc/config/aarch64/aarch64.h
> @@ -179,6 +179,8 @@ enum class aarch64_feature : unsigned char {
>
> /* Macros to test ISA flags. */
>
> +#define AARCH64_ISA_V8A (aarch64_isa_flags & AARCH64_FL_V8A)
> +#define AARCH64_ISA_V8_1A (aarch64_isa_flags & AARCH64_FL_V8_1A)
> #define AARCH64_ISA_CRC (aarch64_isa_flags & AARCH64_FL_CRC)
> #define AARCH64_ISA_CRYPTO (aarch64_isa_flags & AARCH64_FL_CRYPTO)
> #define AARCH64_ISA_FP (aarch64_isa_flags & AARCH64_FL_FP)
> @@ -215,6 +217,8 @@ enum class aarch64_feature : unsigned char {
> #define AARCH64_ISA_SB (aarch64_isa_flags & AARCH64_FL_SB)
> #define AARCH64_ISA_V8R (aarch64_isa_flags & AARCH64_FL_V8R)
> #define AARCH64_ISA_PAUTH (aarch64_isa_flags & AARCH64_FL_PAUTH)
> +#define AARCH64_ISA_V8_7A (aarch64_isa_flags & AARCH64_FL_V8_7A)
> +#define AARCH64_ISA_V8_8A (aarch64_isa_flags & AARCH64_FL_V8_8A)
> #define AARCH64_ISA_V9A (aarch64_isa_flags & AARCH64_FL_V9A)
> #define AARCH64_ISA_V9_1A (aarch64_isa_flags & AARCH64_FL_V9_1A)
> #define AARCH64_ISA_V9_2A (aarch64_isa_flags & AARCH64_FL_V9_2A)
> @@ -223,6 +227,24 @@ enum class aarch64_feature : unsigned char {
> #define AARCH64_ISA_LS64 (aarch64_isa_flags & AARCH64_FL_LS64)
> #define AARCH64_ISA_CSSC (aarch64_isa_flags & AARCH64_FL_CSSC)
>
> +/* AARCH64_FL options necessary for system register implementation. */
> +
> +/* Define AARCH64_FL aliases for architectural features which are protected
> + by -march flags in binutils but which receive no special treatment by GCC.
> +
> + Such flags are inherited from the Binutils definition of system registers
> + and are mapped to the architecture in which the feature is implemented.
> */
> +#define AARCH64_FL_RAS AARCH64_FL_V8A
> +#define AARCH64_FL_LOR AARCH64_FL_V8_1A
> +#define AARCH64_FL_PAN AARCH64_FL_V8_1A
> +#define AARCH64_FL_AMU AARCH64_FL_V8_4A
> +#define AARCH64_FL_SCXTNUM AARCH64_FL_V8_5A
> +#define AARCH64_FL_ID_PFR2 AARCH64_FL_V8_5A
> +
> +/* Define AARCH64_FL aliases for features note yet implemented in GCC.
> + Accept them unconditionally. */
> +#define AARCH64_FL_SME 0
> +
> /* Crypto is an optional extension to AdvSIMD. */
> #define TARGET_CRYPTO (AARCH64_ISA_CRYPTO)
