AArch64 decoder/encoder improvements - Githubissues

DynamoRIO / dynamorio

Dynamic Instrumentation Tool Platform

Other

2.67k stars 562 forks source link

AArch64 decoder/encoder improvements #4393

Open AssadHashmi opened 4 years ago

AssadHashmi commented 4 years ago

The current method of generating decode/encode functions based on the codec.txt bitmap format has limitations in terms of:

Flexibility when specifying instruction aliases and variants, e.g. DC and IC based on SYS, and PRFM. See #4388 and discussion at https://github.com/DynamoRIO/dynamorio/pull/4386#discussion_r462356954.
Extensibility when new versions of the ISA are released, e.g. SVE.
More automation in order to generate as much decode/encode logic as possible from an ISA spec, including multiple operand creation from a single bitfield.

The proposal is to use the publicly available XML specifications to replace codec.txt as the source from which to generate decode/encode functionality. Useful links: https://alastairreid.github.io/ARM-v8a-xml-release/ https://developer.arm.com/architectures/instruction-sets/base-isas/a64 https://github.com/alastairreid/mra_tools

fhahn commented 4 years ago

There are some script to auto-generate parts of codec.txt, tests and instr_create.h macros from an ISA description on the branch: https://github.com/DynamoRIO/dynamorio/commits/project-aarch64-generate-patterns

Not sure how well they aged though.