README.md

cranelift-assembler-x64-meta

This crate generates Cranelift-specific assembly code for x64 instructions. It is designed to fit in with Cranelift-specific logic (e.g., register allocation) and only needs to define the x64 instructions Cranelift emits. It is written in the style of cranelift-codegen-meta and could be migrated there (though not necessarily).

Structure

• dsl.rs: defines a domain-specific language (DSL) for describing x64 instructions; this language is intended to be compact--i.e., define an x64 instruction on a single line--and a close-to-direct mapping of what we read in the x64 developer manual

• instructions.rs: defines x64 instructions using the DSL; add new instructions here

• generate.rs: generates Rust code from the defined instructions to: assemble machine code, pretty-print, register-allocate.

Use

This is primarily intended to be used for generating Rust code, i.e., generate_rust_assembler("some-file.rs"). It also has the ability to print a list of the defined instructions:

$ cargo run
andb: I(al, imm8) => 0x24 ib
andw: I(ax, imm16) => 0x25 iw
andl: I(eax, imm32) => 0x25 id
...

Troubleshooting

When something goes wrong, it can be helpful to compare the output of this assembler with a known-good disassembler like XED.

When testing finds a miscompilation, it prints the emitted bytes. To use XED to disassemble this:

$ <path to xed>/obj/wkit/bin/xed -d 4080

To generate the expected bytes:

$ <path to xed>/obj/wkit/bin/xed -64 -A -e AND bpl IMM:48

XED also documents its CLI interface: Intel XED command interface.