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Ulrich Weigand 10198553c7 ISLE: Common accessors for some insn data fields (#3781 )

Add accessors to prelude.isle to access data fields of
`func_addr` and `symbol_value` instructions.

These are based on similar versions I had added to the s390x
back-end, but are a bit more straightforward to use.

- func_ref_data: Extract SigRef, ExternalName, and RelocDistance
  fields given a FuncRef.

- symbol_value_data: Extract ExternalName, RelocDistance, and
  offset fields given a GlobalValue representing a Symbol.

- reloc_distance_near: Test for RelocDistance::Near.

The s390x back-end is changed to use these common versions.

Note that this exposed a bug in common isle code: This extractor:

(extractor (load_sym inst)
  (and inst
       (load _ (def_inst (symbol_value
                           (symbol_value_data _
                             (reloc_distance_near) offset)))
               (i64_from_offset
                 (memarg_symbol_offset_sum <offset _)))))

would raise an assertion in sema.rs due to a supposed cycle in
extractor definitions.  But there was no actual cycle, it was
simply that the extractor tree refers twice to the `insn_data`
extractor (once via the `load` and once via the `symbol_value`
extractor).  Fixed by checking for pre-existing definitions only
along one path in the tree, not across the whole tree.

2022-02-08 17:57:27 -08:00

src

ISLE: Common accessors for some insn data fields (#3781 )

2022-02-08 17:57:27 -08:00

Cargo.toml

Release Wasmtime 0.34.0 (#3768 )

2022-02-07 19:16:26 -06:00

README.md

Add docs to all public exports and deny(missing_docs) going forward

2021-11-11 15:56:55 -08:00

README.md

ISLE: Instruction Selection / Lowering Expressions

ISLE is a domain specific language (DSL) for instruction selection and lowering clif instructions to vcode's MachInsts in Cranelift.

ISLE is a statically-typed term-rewriting language. You define rewriting rules that map input terms (clif instructions) into output terms (MachInsts). These rules get compiled down into Rust source test that uses a tree of match expressions that is as good or better than what you would have written by hand.