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Issue created by Assad Hashmi@AssadHashmiContributor

Add feature name (FEAT_) support to AArch64 instructions

AArch64 instructions are characterised by a feature name starting with FEAT_, see: https://developer.arm.com/downloads/-/exploration-tools/feature-names-for-a-profile

Implementations of the AArch64 architecture are more accurately described by FEAT_ feature names, than by vX.Y versions, see the explanation at https://github.com/DynamoRIO/dynamorio/pull/5334#issuecomment-1033999742

This issue will clarify how FEAT_ should be implemented. The following is proposed:

  • A new enum dr_isa_feat_t similar to dr_isa_mode_t but for AArch64 only.
  • API accessor functions dr_get_isa_feat() and instr_set_isa_feat().
  • The AArch64 codec will specify the FEAT_ for all instructions after base v8.0.
  • The system registers ID_AA64ISAR0_EL1, ID_AA64ISAR1_EL1 and ID_AA64PFR0_EL1 will be read on DynamoRIO startup in order to establish which FEAT_s are implemented by the h/w. During instruction decode and encode, the instruction's FEAT_ will be checked against the FEAT_ list implemented by the h/w, delivering an error message if the FEAT_ is not implemented.