Stream: git-wasmtime

Topic: wasmtime / PR #10845 asm: refactor VEX implementation

Wasmtime GitHub notifications bot (May 27 2025 at 22:41):

abrown opened PR #10845 from abrown:asm-vex-continued to bytecodealliance:main:

This change adapts the current VEX logic implemented in #10754 to look more like the current infrastructure. To do so:

• it factors out a VexPrefix from the current VexInstruction, allowing us to reuse existing logic for ModR/M and SIB bytes (these do are the same in both REX and VEX encodings)
• it uses compile-time constant bits like the L or pp fields directly, hopefully saving a bit on compile time
• all of this allows more consistent code generation

On the DSL side, this significantly changes how one defines VEX instructions. Many helper methods are added and now documented. It also makes use of a slightly unrelated change included here: I factored out how any encoding can affect the ModR/M byte with ModRmKind. This enum forces the DSL to pick only one of /r or /digit when defining instructions.

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Wasmtime GitHub notifications bot (May 27 2025 at 22:41):

abrown requested cfallin for a review on PR #10845.

Wasmtime GitHub notifications bot (May 27 2025 at 22:41):

abrown requested wasmtime-compiler-reviewers for a review on PR #10845.

Wasmtime GitHub notifications bot (May 27 2025 at 22:53):

cfallin created PR review comment:

Could we define a WBit (or pick your favorite name) enum here with WIG/W0/W1?

Wasmtime GitHub notifications bot (May 27 2025 at 22:53):

cfallin submitted PR review:

Looks reasonable!

Wasmtime GitHub notifications bot (May 28 2025 at 16:41):

abrown updated PR #10845.

Wasmtime GitHub notifications bot (May 28 2025 at 16:43):

abrown has enabled auto merge for PR #10845.

Wasmtime GitHub notifications bot (May 28 2025 at 17:15):

abrown merged PR #10845.

Last updated: Dec 06 2025 at 07:03 UTC