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use llvm_sys::orc2::{
lljit::{
LLVMOrcCreateLLJIT, LLVMOrcLLJITAddLLVMIRModuleWithRT, LLVMOrcLLJITGetGlobalPrefix,
LLVMOrcLLJITGetMainJITDylib, LLVMOrcLLJITLookup, LLVMOrcLLJITRef,
},
LLVMOrcCreateDynamicLibrarySearchGeneratorForProcess, LLVMOrcDefinitionGeneratorRef,
LLVMOrcJITDylibAddGenerator, LLVMOrcJITDylibCreateResourceTracker, LLVMOrcJITDylibRef,
LLVMOrcReleaseResourceTracker, LLVMOrcResourceTrackerRef, LLVMOrcResourceTrackerRemove,
};
use std::convert::TryFrom;
use std::marker::PhantomData;
use super::{Error, Module};
use crate::SmallCStr;
/// Marker trait to constrain function signatures that can be looked up in the JIT.
pub trait JitFn {}
impl JitFn for unsafe extern "C" fn() -> f64 {}
/// Wrapper for a LLVM [LLJIT](https://www.llvm.org/docs/ORCv2.html#lljit-and-lllazyjit).
pub struct LLJit {
jit: LLVMOrcLLJITRef,
dylib: LLVMOrcJITDylibRef,
}
impl LLJit {
/// Create a new LLJit instance.
///
/// # Panics
///
/// Panics if LLVM API returns a `null` pointer or an error.
pub fn new() -> LLJit {
let (jit, dylib) = unsafe {
let mut jit = std::ptr::null_mut();
let err = LLVMOrcCreateLLJIT(
&mut jit as _,
std::ptr::null_mut(), /* builder: nullptr -> default */
);
if let Some(err) = Error::from(err) {
panic!("Error: {}", err.as_str());
}
let dylib = LLVMOrcLLJITGetMainJITDylib(jit);
assert!(!dylib.is_null());
(jit, dylib)
};
LLJit { jit, dylib }
}
/// Add an LLVM IR module to the JIT. Return a [`ResourceTracker`], which when dropped, will
/// remove the code of the LLVM IR module from the JIT.
///
/// # Panics
///
/// Panics if LLVM API returns a `null` pointer or an error.
pub fn add_module(&self, module: Module) -> ResourceTracker<'_> {
let tsmod = module.into_raw_thread_safe_module();
let rt = unsafe {
let rt = LLVMOrcJITDylibCreateResourceTracker(self.dylib);
let err = LLVMOrcLLJITAddLLVMIRModuleWithRT(self.jit, rt, tsmod);
if let Some(err) = Error::from(err) {
panic!("Error: {}", err.as_str());
}
rt
};
ResourceTracker::new(rt)
}
/// Find the symbol with the name `sym` in the JIT.
///
/// # Panics
///
/// Panics if the symbol is not found in the JIT.
pub fn find_symbol<F: JitFn>(&self, sym: &str) -> F {
let sym =
SmallCStr::try_from(sym).expect("Failed to convert 'sym' argument to small C string!");
unsafe {
let mut addr = 0u64;
let err = LLVMOrcLLJITLookup(self.jit, &mut addr as _, sym.as_ptr());
if let Some(err) = Error::from(err) {
panic!("Error: {}", err.as_str());
}
debug_assert_eq!(core::mem::size_of_val(&addr), core::mem::size_of::<F>());
std::mem::transmute_copy(&addr)
}
}
/// Enable lookup of dynamic symbols available in the current process from the JIT.
///
/// # Panics
///
/// Panics if LLVM API returns an error.
pub fn enable_process_symbols(&self) {
unsafe {
let mut proc_syms_gen: LLVMOrcDefinitionGeneratorRef = std::ptr::null_mut();
let err = LLVMOrcCreateDynamicLibrarySearchGeneratorForProcess(
&mut proc_syms_gen as _,
self.global_prefix(),
None, /* filter */
std::ptr::null_mut(), /* filter ctx */
);
if let Some(err) = Error::from(err) {
panic!("Error: {}", err.as_str());
}
LLVMOrcJITDylibAddGenerator(self.dylib, proc_syms_gen);
}
}
/// Return the global prefix character according to the LLJITs data layout.
fn global_prefix(&self) -> libc::c_char {
unsafe { LLVMOrcLLJITGetGlobalPrefix(self.jit) }
}
}
/// A resource handle for code added to an [`LLJit`] instance.
///
/// When a `ResourceTracker` handle is dropped, the code corresponding to the handle will be
/// removed from the JIT.
pub struct ResourceTracker<'jit>(LLVMOrcResourceTrackerRef, PhantomData<&'jit ()>);
impl<'jit> ResourceTracker<'jit> {
fn new(rt: LLVMOrcResourceTrackerRef) -> ResourceTracker<'jit> {
assert!(!rt.is_null());
ResourceTracker(rt, PhantomData)
}
}
impl Drop for ResourceTracker<'_> {
fn drop(&mut self) {
unsafe {
let err = LLVMOrcResourceTrackerRemove(self.0);
if let Some(err) = Error::from(err) {
panic!("Error: {}", err.as_str());
}
LLVMOrcReleaseResourceTracker(self.0);
};
}
}
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