Andreas Kling 200103b0af LibJS: Add AsmInterpreter, a low-level assembly bytecode interpreter ...

Add a new interpreter that executes bytecode via generated assembly,
written in a custom DSL (asmint.asm) that AsmIntGen compiles to
native x86_64 or aarch64 code.

The interpreter keeps the bytecode program counter and register file
pointer in machine registers for fast access, dispatching opcodes
through a jump table. Hot paths (arithmetic, comparisons, property
access on simple objects) are handled entirely in assembly, with
cold/complex operations calling into C++ helper functions defined
in AsmInterpreter.cpp.

A small build-time tool (gen_asm_offsets) uses offsetof() to emit
struct field offsets as constants consumed by the DSL, ensuring the
assembly stays in sync with C++ struct layouts.

The interpreter is enabled by default on platforms that support it.
The C++ interpreter can be selected via LIBJS_USE_CPP_INTERPRETER=1.

Currently supported platforms:
- Linux/x86_64
- Linux/aarch64
- macOS/x86_64
- macOS/aarch64

2026-03-07 13:09:59 +01:00

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