1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
use libc::c_int;
use llvm_sys::execution_engine::{
    LLVMAddGlobalMapping, LLVMAddModule, LLVMDisposeExecutionEngine, LLVMExecutionEngineRef, LLVMFindFunction,
    LLVMFreeMachineCodeForFunction, LLVMGenericValueRef, LLVMGetExecutionEngineTargetData, LLVMGetFunctionAddress,
    LLVMLinkInInterpreter, LLVMLinkInMCJIT, LLVMRemoveModule, LLVMRunFunction, LLVMRunFunctionAsMain,
    LLVMRunStaticConstructors, LLVMRunStaticDestructors,
};

use crate::context::Context;
use crate::module::Module;
use crate::support::{to_c_str, LLVMString};
use crate::targets::TargetData;
use crate::values::{AnyValue, AsValueRef, FunctionValue, GenericValue};

use std::error::Error;
use std::fmt::{self, Debug, Display, Formatter};
use std::marker::PhantomData;
use std::mem::{forget, size_of, transmute_copy, MaybeUninit};
use std::ops::Deref;
use std::rc::Rc;

static EE_INNER_PANIC: &str = "ExecutionEngineInner should exist until Drop";

#[derive(Debug, PartialEq, Eq)]
pub enum FunctionLookupError {
    JITNotEnabled,
    FunctionNotFound, // 404!
}

impl Error for FunctionLookupError {}

impl FunctionLookupError {
    fn as_str(&self) -> &str {
        match self {
            FunctionLookupError::JITNotEnabled => "ExecutionEngine does not have JIT functionality enabled",
            FunctionLookupError::FunctionNotFound => "Function not found in ExecutionEngine",
        }
    }
}

impl Display for FunctionLookupError {
    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
        write!(f, "FunctionLookupError({})", self.as_str())
    }
}

#[derive(Debug, PartialEq, Eq)]
pub enum RemoveModuleError {
    ModuleNotOwned,
    IncorrectModuleOwner,
    LLVMError(LLVMString),
}

impl Error for RemoveModuleError {
    // This method is deprecated on nighty so it's probably not
    // something we should worry about
    fn description(&self) -> &str {
        self.as_str()
    }

    fn cause(&self) -> Option<&dyn Error> {
        None
    }
}

impl RemoveModuleError {
    fn as_str(&self) -> &str {
        match self {
            RemoveModuleError::ModuleNotOwned => "Module is not owned by an Execution Engine",
            RemoveModuleError::IncorrectModuleOwner => "Module is not owned by this Execution Engine",
            RemoveModuleError::LLVMError(string) => string.to_str().unwrap_or("LLVMError with invalid unicode"),
        }
    }
}

impl Display for RemoveModuleError {
    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
        write!(f, "RemoveModuleError({})", self.as_str())
    }
}

/// A reference-counted wrapper around LLVM's execution engine.
///
/// # Note
///
/// Cloning this object is essentially just a case of copying a couple pointers
/// and incrementing one or two atomics, so this should be quite cheap to create
/// copies. The underlying LLVM object will be automatically deallocated when
/// there are no more references to it.
#[derive(PartialEq, Eq, Debug)]
pub struct ExecutionEngine<'ctx> {
    execution_engine: Option<ExecEngineInner<'ctx>>,
    target_data: Option<TargetData>,
    jit_mode: bool,
}

impl<'ctx> ExecutionEngine<'ctx> {
    pub unsafe fn new(execution_engine: Rc<LLVMExecutionEngineRef>, jit_mode: bool) -> Self {
        assert!(!execution_engine.is_null());

        // REVIEW: Will we have to do this for LLVMGetExecutionEngineTargetMachine too?
        let target_data = LLVMGetExecutionEngineTargetData(*execution_engine);

        ExecutionEngine {
            execution_engine: Some(ExecEngineInner(execution_engine, PhantomData)),
            target_data: Some(TargetData::new(target_data)),
            jit_mode,
        }
    }

    /// Acquires the underlying raw pointer belonging to this `ExecutionEngine` type.
    pub fn as_mut_ptr(&self) -> LLVMExecutionEngineRef {
        self.execution_engine_inner()
    }

    pub(crate) fn execution_engine_rc(&self) -> &Rc<LLVMExecutionEngineRef> {
        &self.execution_engine.as_ref().expect(EE_INNER_PANIC).0
    }

    #[inline]
    pub(crate) fn execution_engine_inner(&self) -> LLVMExecutionEngineRef {
        **self.execution_engine_rc()
    }

    /// This function probably doesn't need to be called, but is here due to
    /// linking(?) requirements. Bad things happen if we don't provide it.
    pub fn link_in_mc_jit() {
        unsafe { LLVMLinkInMCJIT() }
    }

    /// This function probably doesn't need to be called, but is here due to
    /// linking(?) requirements. Bad things happen if we don't provide it.
    pub fn link_in_interpreter() {
        unsafe {
            LLVMLinkInInterpreter();
        }
    }

    /// Maps the specified value to an address.
    ///
    /// # Example
    /// ```no_run
    /// use inkwell::targets::{InitializationConfig, Target};
    /// use inkwell::context::Context;
    /// use inkwell::OptimizationLevel;
    ///
    /// Target::initialize_native(&InitializationConfig::default()).unwrap();
    ///
    /// extern fn sumf(a: f64, b: f64) -> f64 {
    ///     a + b
    /// }
    ///
    /// let context = Context::create();
    /// let module = context.create_module("test");
    /// let builder = context.create_builder();
    ///
    /// let ft = context.f64_type();
    /// let fnt = ft.fn_type(&[], false);
    ///
    /// let f = module.add_function("test_fn", fnt, None);
    /// let b = context.append_basic_block(f, "entry");
    ///
    /// builder.position_at_end(b);
    ///
    /// let extf = module.add_function("sumf", ft.fn_type(&[ft.into(), ft.into()], false), None);
    ///
    /// let argf = ft.const_float(64.);
    /// let call_site_value = builder.build_call(extf, &[argf.into(), argf.into()], "retv").unwrap();
    /// let retv = call_site_value.try_as_basic_value().left().unwrap().into_float_value();
    ///
    /// builder.build_return(Some(&retv)).unwrap();
    ///
    /// let mut ee = module.create_jit_execution_engine(OptimizationLevel::None).unwrap();
    /// ee.add_global_mapping(&extf, sumf as usize);
    ///
    /// let result = unsafe { ee.run_function(f, &[]) }.as_float(&ft);
    ///
    /// assert_eq!(result, 128.);
    /// ```
    pub fn add_global_mapping(&self, value: &dyn AnyValue<'ctx>, addr: usize) {
        unsafe { LLVMAddGlobalMapping(self.execution_engine_inner(), value.as_value_ref(), addr as *mut _) }
    }

    /// Adds a module to an `ExecutionEngine`.
    ///
    /// The method will be `Ok(())` if the module does not belong to an `ExecutionEngine` already and `Err(())` otherwise.
    ///
    /// ```rust,no_run
    /// use inkwell::targets::{InitializationConfig, Target};
    /// use inkwell::context::Context;
    /// use inkwell::OptimizationLevel;
    ///
    /// Target::initialize_native(&InitializationConfig::default()).unwrap();
    ///
    /// let context = Context::create();
    /// let module = context.create_module("test");
    /// let mut ee = module.create_jit_execution_engine(OptimizationLevel::None).unwrap();
    ///
    /// assert!(ee.add_module(&module).is_err());
    /// ```
    pub fn add_module(&self, module: &Module<'ctx>) -> Result<(), ()> {
        unsafe { LLVMAddModule(self.execution_engine_inner(), module.module.get()) }

        if module.owned_by_ee.borrow().is_some() {
            return Err(());
        }

        *module.owned_by_ee.borrow_mut() = Some(self.clone());

        Ok(())
    }

    pub fn remove_module(&self, module: &Module<'ctx>) -> Result<(), RemoveModuleError> {
        match *module.owned_by_ee.borrow() {
            Some(ref ee) if ee.execution_engine_inner() != self.execution_engine_inner() => {
                return Err(RemoveModuleError::IncorrectModuleOwner)
            },
            None => return Err(RemoveModuleError::ModuleNotOwned),
            _ => (),
        }

        let mut new_module = MaybeUninit::uninit();
        let mut err_string = MaybeUninit::uninit();

        let code = unsafe {
            LLVMRemoveModule(
                self.execution_engine_inner(),
                module.module.get(),
                new_module.as_mut_ptr(),
                err_string.as_mut_ptr(),
            )
        };

        if code == 1 {
            unsafe {
                return Err(RemoveModuleError::LLVMError(LLVMString::new(err_string.assume_init())));
            }
        }

        let new_module = unsafe { new_module.assume_init() };

        module.module.set(new_module);
        *module.owned_by_ee.borrow_mut() = None;

        Ok(())
    }

    /// Try to load a function from the execution engine.
    ///
    /// If a target hasn't already been initialized, spurious "function not
    /// found" errors may be encountered.
    ///
    /// The [`UnsafeFunctionPointer`] trait is designed so only `unsafe extern
    /// "C"` functions can be retrieved via the `get_function()` method. If you
    /// get funny type errors then it's probably because you have specified the
    /// wrong calling convention or forgotten to specify the retrieved function
    /// as `unsafe`.
    ///
    /// # Examples
    ///
    ///
    /// ```rust,no_run
    /// # use inkwell::targets::{InitializationConfig, Target};
    /// # use inkwell::context::Context;
    /// # use inkwell::OptimizationLevel;
    /// # Target::initialize_native(&InitializationConfig::default()).unwrap();
    /// let context = Context::create();
    /// let module = context.create_module("test");
    /// let builder = context.create_builder();
    ///
    /// // Set up the function signature
    /// let double = context.f64_type();
    /// let sig = double.fn_type(&[], false);
    ///
    /// // Add the function to our module
    /// let f = module.add_function("test_fn", sig, None);
    /// let b = context.append_basic_block(f, "entry");
    /// builder.position_at_end(b);
    ///
    /// // Insert a return statement
    /// let ret = double.const_float(64.0);
    /// builder.build_return(Some(&ret)).unwrap();
    ///
    /// // create the JIT engine
    /// let mut ee = module.create_jit_execution_engine(OptimizationLevel::None).unwrap();
    ///
    /// // fetch our JIT'd function and execute it
    /// unsafe {
    ///     let test_fn = ee.get_function::<unsafe extern "C" fn() -> f64>("test_fn").unwrap();
    ///     let return_value = test_fn.call();
    ///     assert_eq!(return_value, 64.0);
    /// }
    /// ```
    ///
    /// # Safety
    ///
    /// It is the caller's responsibility to ensure they call the function with
    /// the correct signature and calling convention.
    ///
    /// The `JitFunction` wrapper ensures a function won't accidentally outlive the
    /// execution engine it came from, but adding functions after calling this
    /// method *may* invalidate the function pointer.
    ///
    /// [`UnsafeFunctionPointer`]: trait.UnsafeFunctionPointer.html
    pub unsafe fn get_function<F>(&self, fn_name: &str) -> Result<JitFunction<'ctx, F>, FunctionLookupError>
    where
        F: UnsafeFunctionPointer,
    {
        if !self.jit_mode {
            return Err(FunctionLookupError::JITNotEnabled);
        }

        let address = self.get_function_address(fn_name)?;

        assert_eq!(
            size_of::<F>(),
            size_of::<usize>(),
            "The type `F` must have the same size as a function pointer"
        );

        let execution_engine = self.execution_engine.as_ref().expect(EE_INNER_PANIC);

        Ok(JitFunction {
            _execution_engine: execution_engine.clone(),
            inner: transmute_copy(&address),
        })
    }

    /// Attempts to look up a function's address by its name. May return Err if the function cannot be
    /// found or some other unknown error has occurred.
    ///
    /// It is recommended to use `get_function` instead of this method when intending to call the function
    /// pointer so that you don't have to do error-prone transmutes yourself.
    pub fn get_function_address(&self, fn_name: &str) -> Result<usize, FunctionLookupError> {
        // LLVMGetFunctionAddress segfaults in llvm 5.0 -> 8.0 when fn_name doesn't exist. This is a workaround
        // to see if it exists and avoid the segfault when it doesn't
        #[cfg(any(feature = "llvm5-0", feature = "llvm6-0", feature = "llvm7-0", feature = "llvm8-0"))]
        self.get_function_value(fn_name)?;

        let c_string = to_c_str(fn_name);
        let address = unsafe { LLVMGetFunctionAddress(self.execution_engine_inner(), c_string.as_ptr()) };

        // REVIEW: Can also return 0 if no targets are initialized.
        // One option might be to set a (thread local?) global to true if any at all of the targets have been
        // initialized (maybe we could figure out which config in particular is the trigger)
        // and if not return an "NoTargetsInitialized" error, instead of not found.
        if address == 0 {
            return Err(FunctionLookupError::FunctionNotFound);
        }

        Ok(address as usize)
    }

    // REVIEW: Not sure if an EE's target data can change.. if so we might want to update the value
    // when making this call
    pub fn get_target_data(&self) -> &TargetData {
        self.target_data
            .as_ref()
            .expect("TargetData should always exist until Drop")
    }

    // REVIEW: Can also find nothing if no targeting is initialized. Maybe best to
    // do have a global flag for anything initialized. Catch is that it must be initialized
    // before EE is created
    // REVIEW: Should FunctionValue lifetime be tied to self not 'ctx?
    pub fn get_function_value(&self, fn_name: &str) -> Result<FunctionValue<'ctx>, FunctionLookupError> {
        if !self.jit_mode {
            return Err(FunctionLookupError::JITNotEnabled);
        }

        let c_string = to_c_str(fn_name);
        let mut function = MaybeUninit::uninit();

        let code = unsafe { LLVMFindFunction(self.execution_engine_inner(), c_string.as_ptr(), function.as_mut_ptr()) };

        if code == 0 {
            return unsafe { FunctionValue::new(function.assume_init()).ok_or(FunctionLookupError::FunctionNotFound) };
        };

        Err(FunctionLookupError::FunctionNotFound)
    }

    // TODOC: Marked as unsafe because input function could very well do something unsafe. It's up to the caller
    // to ensure that doesn't happen by defining their function correctly.
    pub unsafe fn run_function(
        &self,
        function: FunctionValue<'ctx>,
        args: &[&GenericValue<'ctx>],
    ) -> GenericValue<'ctx> {
        let mut args: Vec<LLVMGenericValueRef> = args.iter().map(|val| val.generic_value).collect();

        let value = LLVMRunFunction(
            self.execution_engine_inner(),
            function.as_value_ref(),
            args.len() as u32,
            args.as_mut_ptr(),
        ); // REVIEW: usize to u32 ok??

        GenericValue::new(value)
    }

    // TODOC: Marked as unsafe because input function could very well do something unsafe. It's up to the caller
    // to ensure that doesn't happen by defining their function correctly.
    // SubType: Only for JIT EEs?
    pub unsafe fn run_function_as_main(&self, function: FunctionValue<'ctx>, args: &[&str]) -> c_int {
        let cstring_args: Vec<_> = args.iter().map(|&arg| to_c_str(arg)).collect();
        let raw_args: Vec<*const _> = cstring_args.iter().map(|arg| arg.as_ptr()).collect();

        let environment_variables = []; // TODO: Support envp. Likely needs to be null terminated

        LLVMRunFunctionAsMain(
            self.execution_engine_inner(),
            function.as_value_ref(),
            raw_args.len() as u32,
            raw_args.as_ptr(),
            environment_variables.as_ptr(),
        ) // REVIEW: usize to u32 cast ok??
    }

    pub fn free_fn_machine_code(&self, function: FunctionValue<'ctx>) {
        unsafe { LLVMFreeMachineCodeForFunction(self.execution_engine_inner(), function.as_value_ref()) }
    }

    // REVIEW: Is this actually safe?
    pub fn run_static_constructors(&self) {
        unsafe { LLVMRunStaticConstructors(self.execution_engine_inner()) }
    }

    // REVIEW: Is this actually safe? Can you double destruct/free?
    pub fn run_static_destructors(&self) {
        unsafe { LLVMRunStaticDestructors(self.execution_engine_inner()) }
    }
}

// Modules owned by the EE will be discarded by the EE so we don't
// want owned modules to drop.
impl Drop for ExecutionEngine<'_> {
    fn drop(&mut self) {
        forget(
            self.target_data
                .take()
                .expect("TargetData should always exist until Drop"),
        );

        // We must ensure the EE gets dropped before its context does,
        // which is important in the case where the EE has the last
        // remaining reference to it context
        drop(self.execution_engine.take().expect(EE_INNER_PANIC));
    }
}

impl Clone for ExecutionEngine<'_> {
    fn clone(&self) -> Self {
        let execution_engine_rc = self.execution_engine_rc().clone();

        unsafe { ExecutionEngine::new(execution_engine_rc, self.jit_mode) }
    }
}

/// A smart pointer which wraps the `Drop` logic for `LLVMExecutionEngineRef`.
#[derive(Debug, Clone, PartialEq, Eq)]
struct ExecEngineInner<'ctx>(Rc<LLVMExecutionEngineRef>, PhantomData<&'ctx Context>);

impl Drop for ExecEngineInner<'_> {
    fn drop(&mut self) {
        if Rc::strong_count(&self.0) == 1 {
            unsafe {
                LLVMDisposeExecutionEngine(*self.0);
            }
        }
    }
}

impl Deref for ExecEngineInner<'_> {
    type Target = LLVMExecutionEngineRef;

    fn deref(&self) -> &Self::Target {
        &self.0
    }
}

/// A wrapper around a function pointer which ensures the function being pointed
/// to doesn't accidentally outlive its execution engine.
#[derive(Clone)]
pub struct JitFunction<'ctx, F> {
    _execution_engine: ExecEngineInner<'ctx>,
    inner: F,
}

impl<'ctx, F: Copy> JitFunction<'ctx, F> {
    /// Returns the raw function pointer, consuming self in the process.
    /// This function is unsafe because the function pointer may dangle
    /// if the ExecutionEngine it came from is dropped. The caller is
    /// thus responsible for ensuring the ExecutionEngine remains valid.
    pub unsafe fn into_raw(self) -> F {
        self.inner
    }

    /// Returns the raw function pointer.
    /// This function is unsafe because the function pointer may dangle
    /// if the ExecutionEngine it came from is dropped. The caller is
    /// thus responsible for ensuring the ExecutionEngine remains valid.
    pub unsafe fn as_raw(&self) -> F {
        self.inner
    }
}

impl<F> Debug for JitFunction<'_, F> {
    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
        f.debug_tuple("JitFunction").field(&"<unnamed>").finish()
    }
}

/// Marker trait representing an unsafe function pointer (`unsafe extern "C" fn(A, B, ...) -> Output`).
pub trait UnsafeFunctionPointer: private::SealedUnsafeFunctionPointer {}

mod private {
    /// A sealed trait which ensures nobody outside this crate can implement
    /// `UnsafeFunctionPointer`.
    ///
    /// See https://rust-lang-nursery.github.io/api-guidelines/future-proofing.html
    pub trait SealedUnsafeFunctionPointer: Copy {}
}

impl<F: private::SealedUnsafeFunctionPointer> UnsafeFunctionPointer for F {}

macro_rules! impl_unsafe_fn {
    (@recurse $first:ident $( , $rest:ident )*) => {
        impl_unsafe_fn!($( $rest ),*);
    };

    (@recurse) => {};

    ($( $param:ident ),*) => {
        impl<Output, $( $param ),*> private::SealedUnsafeFunctionPointer for unsafe extern "C" fn($( $param ),*) -> Output {}

        impl<Output, $( $param ),*> JitFunction<'_, unsafe extern "C" fn($( $param ),*) -> Output> {
            /// This method allows you to call the underlying function while making
            /// sure that the backing storage is not dropped too early and
            /// preserves the `unsafe` marker for any calls.
            #[allow(non_snake_case)]
            #[inline(always)]
            pub unsafe fn call(&self, $( $param: $param ),*) -> Output {
                (self.inner)($( $param ),*)
            }
        }

        impl_unsafe_fn!(@recurse $( $param ),*);
    };
}

impl_unsafe_fn!(A, B, C, D, E, F, G, H, I, J, K, L, M);

#[cfg(feature = "experimental")]
pub mod experimental {
    use llvm_sys::error::{LLVMConsumeError, LLVMErrorRef, LLVMErrorTypeId, LLVMGetErrorMessage, LLVMGetErrorTypeId};
    use llvm_sys::orc::{
        LLVMOrcAddEagerlyCompiledIR, LLVMOrcAddLazilyCompiledIR, LLVMOrcCreateInstance, LLVMOrcDisposeInstance,
        LLVMOrcDisposeMangledSymbol, LLVMOrcGetErrorMsg, LLVMOrcGetMangledSymbol, LLVMOrcJITStackRef,
    };

    use crate::module::Module;
    use crate::support::to_c_str;
    use crate::targets::TargetMachine;

    use std::ffi::{CStr, CString};
    use std::mem::MaybeUninit;
    use std::ops::Deref;

    #[derive(Debug)]
    pub struct MangledSymbol(*mut libc::c_char);

    impl Deref for MangledSymbol {
        type Target = CStr;

        fn deref(&self) -> &CStr {
            unsafe { CStr::from_ptr(self.0) }
        }
    }

    impl Drop for MangledSymbol {
        fn drop(&mut self) {
            unsafe { LLVMOrcDisposeMangledSymbol(self.0) }
        }
    }

    #[derive(Debug)]
    pub struct LLVMError(LLVMErrorRef);

    impl LLVMError {
        // Null type id == success
        pub fn get_type_id(&self) -> LLVMErrorTypeId {
            // FIXME: Don't expose LLVMErrorTypeId
            unsafe { LLVMGetErrorTypeId(self.0) }
        }
    }

    impl Deref for LLVMError {
        type Target = CStr;

        fn deref(&self) -> &CStr {
            unsafe {
                CStr::from_ptr(LLVMGetErrorMessage(self.0)) // FIXME: LLVMGetErrorMessage consumes the error, needs LLVMDisposeErrorMessage after
            }
        }
    }

    impl Drop for LLVMError {
        fn drop(&mut self) {
            unsafe { LLVMConsumeError(self.0) }
        }
    }

    // TODO
    #[derive(Debug)]
    pub struct Orc(LLVMOrcJITStackRef);

    impl Orc {
        pub fn create(target_machine: TargetMachine) -> Self {
            let stack_ref = unsafe { LLVMOrcCreateInstance(target_machine.target_machine) };

            Orc(stack_ref)
        }

        pub fn add_compiled_ir<'ctx>(&self, module: &Module<'ctx>, lazily: bool) -> Result<(), ()> {
            // let handle = MaybeUninit::uninit();
            // let _err =  if lazily {
            //     unsafe { LLVMOrcAddLazilyCompiledIR(self.0, handle.as_mut_ptr(), module.module.get(), sym_resolve, sym_resolve_ctx) }
            // } else {
            //     unsafe { LLVMOrcAddEagerlyCompiledIR(self.0, handle.as_mut_ptr(), module.module.get(), sym_resolve, sym_resolve_ctx) }
            // };

            Ok(())
        }

        /// Obtains an error message owned by the ORC JIT stack.
        pub fn get_error(&self) -> &CStr {
            let err_str = unsafe { LLVMOrcGetErrorMsg(self.0) };

            if err_str.is_null() {
                panic!("Needs to be optional")
            }

            unsafe { CStr::from_ptr(err_str) }
        }

        pub fn get_mangled_symbol(&self, symbol: &str) -> MangledSymbol {
            let mut mangled_symbol = MaybeUninit::uninit();
            let c_symbol = to_c_str(symbol);

            unsafe { LLVMOrcGetMangledSymbol(self.0, mangled_symbol.as_mut_ptr(), c_symbol.as_ptr()) };

            MangledSymbol(unsafe { mangled_symbol.assume_init() })
        }
    }

    impl Drop for Orc {
        fn drop(&mut self) {
            // REVIEW: This returns an LLVMErrorRef, not sure what we can do with it...
            // print to stderr maybe?
            LLVMError(unsafe { LLVMOrcDisposeInstance(self.0) });
        }
    }

    #[test]
    fn test_mangled_str() {
        use crate::targets::{CodeModel, InitializationConfig, RelocMode, Target};
        use crate::OptimizationLevel;

        Target::initialize_native(&InitializationConfig::default()).unwrap();

        let target_triple = TargetMachine::get_default_triple();
        let target = Target::from_triple(&target_triple).unwrap();
        let target_machine = target
            .create_target_machine(
                &target_triple,
                &"",
                &"",
                OptimizationLevel::None,
                RelocMode::Default,
                CodeModel::Default,
            )
            .unwrap();
        let orc = Orc::create(target_machine);

        assert_eq!(orc.get_error().to_str().unwrap(), "");

        let mangled_symbol = orc.get_mangled_symbol("MyStructName");

        assert_eq!(orc.get_error().to_str().unwrap(), "");

        // REVIEW: This doesn't seem very mangled...
        assert_eq!(mangled_symbol.to_str().unwrap(), "MyStructName");
    }
}