Unsupported opcode fallback

[ailrst]

Emit a Stmt_TCall("unsupported_opcode", Expr_IntLiteral(opcode)) on lift failures rather than crashing. This occurs currently due to svc, ldaxr, and mrs instructions

          "svc #0": [
            "Stmt_TCall(\"unsupported_opcode.0\",[],[3556769793])"
          "ldaxr w2, [x21]": [
            "Stmt_TCall(\"unsupported_opcode.0\",[],[2287992482])"
          ]
          "mrs x0, FPSR": [
            "Stmt_TCall(\"unsupported_opcode.0\",[],[3577431072])"
          ]

Also fixed dune config for new release of ocaml_protoc_plugin

[katrinafyi]

lgtm aside from typo.

it would be nice to make this configurable by a command-line argument, in case one wanted to see the stack trace from failed instructions. but this could come later.

[katrinafyi]

it occurs to me that this is better placed within aslp, especially since it introduces a new kind of intrinsic. but this can be merged for now.

[katrinafyi]

Maybe it would be better to use a distinct JSON structure to represent the error, instead of embedding it as a fake ASL statement.

[katrinafyi]

"use a distinct JSON structure to represent the error, instead of embedding it as a fake ASL statement".

[ailrst]

Probably implement as a map containing the same information (debug gts output):

    "+YG2ow7IRuybtIDNCYkdUw==": {
      "name": "__sfp_handle_exceptions [ 7/11]",
--
          "assembly": "fmul s0, s1, s1",
          "semantics": [
            "Stmt_ConstDecl(Type_Bits(32),\"Exp9__5\",Expr_TApply(\"FPMul.0\",[32],[Expr_Slices(Expr_Array(Expr_Var(\"_Z\"),1),[Slice_LoWd(0,32)]);Expr_Slices(Expr_Array(Expr_Var(\"
_Z\"),1),[Slice_LoWd(0,32)]);Expr_Var(\"FPCR\")]))",
            "Stmt_Assign(LExpr_Array(LExpr_Var(\"_Z\"),0),Expr_TApply(\"ZeroExtend.0\",[32;128],[Expr_Var(\"Exp9__5\");128]))"
          ]
        },
        {
          "address": "0x0040f0a0 (4255904)",
          "assembly": "mrs x1, FPSR",
          "semantics": {
            "decode_error": {
              "opcode": "0xd53b4421",
              "error": "Failure(\"Casting unhandled value type to expression: {.NS = 1'0', .exceptype = Exception_AdvSIMDFPAccessTrap, .ipaddress = 52'000000000000000000000000000000
0000000000000000000000', .ipavalid = FALSE, .syndrome = 25'0000000000000000000000000', .vaddress = 64'0000000000000000000000000000000000000000000000000000000000000000'}\")"
            }
          }
        }
      ],

[ailrst]

lgtm

[katrinafyi]

forecast looks good