Struct juicebox_asm::Runtime

pub struct Runtime { /* private fields */ }

A simple mmaped runtime with executable pages.

Implementations

impl Runtime

pub fn new() -> Runtime

Create a new Runtime.

Panics

Panics if the mmap call fails.

pub fn with_profile() -> Runtime

Create a new Runtime which also generates static perf metat data.

For each function added to the Runtime, an entry will be generated in the /tmp/perf-<PID>.map file, which perf report uses to symbolicate unknown addresses. This is applicable for static runtimes only.

Panics

Panics if the mmap call fails.

pub unsafe fn add_code<F>(&mut self, code: impl AsRef<[u8]>) -> F

Add the block of code to the runtime and a get function pointer of type F.

Panics

Panics if the code does not fit on the mmaped pages or is empty.

Safety

The code added must fulfill the ABI of the specified function F and the returned function pointer is only valid until the Runtime is dropped.

Examples

let mut rt = juicebox_asm::Runtime::new();

let code = [ 0x90 /* nop */, 0xc3 /* ret */ ];
let nop = unsafe { rt.add_code::<extern "C" fn()>(&code) };

nop();

pub fn dump(&self)

Dump the code added so far to the runtime into a file called jit.asm in the processes current working directory.

The code can be inspected with a disassembler as for example ndiasm from nasm.us.

ndisasm -b 64 jit.asm

Panics

Panics if writing the file failed.

Trait Implementations

impl Drop for Runtime

fn drop(&mut self)

Unmaps the code page. This invalidates all the function pointer returned by Runtime::add_code.