path: root/src/llvm/mod.rs

//! Safe wrapper around the LLVM C API.
//!
//! References returned from the LLVM API are tied to the `'llvm` lifetime which is bound to the
//! context where the objects are created in.
//! We do not offer wrappers to remove or delete any objects in the context and therefore all the
//! references will be valid for the liftime of the context.
//!
//! For the scope of this tutorial we mainly use assertions to validate the results from the LLVM
//! API calls.

use llvm_sys::{
    core::LLVMShutdown,
    error::{LLVMDisposeErrorMessage, LLVMErrorRef, LLVMGetErrorMessage},
    prelude::LLVMBasicBlockRef,
    target::{
        LLVM_InitializeNativeAsmParser, LLVM_InitializeNativeAsmPrinter,
        LLVM_InitializeNativeTarget,
    },
};

use std::ffi::CStr;
use std::marker::PhantomData;

mod builder;
mod lljit;
mod module;
mod pass_manager;
mod type_;
mod value;

pub use builder::IRBuilder;
pub use lljit::{LLJit, ResourceTracker};
pub use module::Module;
pub use pass_manager::FunctionPassManager;
pub use type_::Type;
pub use value::{FnValue, Value};

/// Wrapper for a LLVM Basic Block.
#[derive(Copy, Clone)]
pub struct BasicBlock<'llvm>(LLVMBasicBlockRef, PhantomData<&'llvm ()>);

struct Error<'llvm>(&'llvm mut libc::c_char);

impl<'llvm> Error<'llvm> {
    fn from(err: LLVMErrorRef) -> Option<Error<'llvm>> {
        (!err.is_null()).then(|| Error(unsafe { &mut *LLVMGetErrorMessage(err) }))
    }

    fn as_str(&self) -> &str {
        unsafe { CStr::from_ptr(self.0) }
            .to_str()
            .expect("Expected valid UTF8 string from LLVM API")
    }
}

impl Drop for Error<'_> {
    fn drop(&mut self) {
        unsafe {
            LLVMDisposeErrorMessage(self.0 as *mut libc::c_char);
        }
    }
}

/// Initialize native target for corresponding to host (useful for jitting).
pub fn initialize_native_taget() {
    unsafe {
        assert_eq!(LLVM_InitializeNativeTarget(), 0);
        assert_eq!(LLVM_InitializeNativeAsmParser(), 0);
        assert_eq!(LLVM_InitializeNativeAsmPrinter(), 0);
    }
}

/// Deallocate and destroy all "ManagedStatic" variables.
pub fn shutdown() {
    unsafe {
        LLVMShutdown();
    };
}