Move FromCuda and ZludaObject into a common crate (#452)

* Refactor FromCuda error type to be generic

* Create zluda_common crate

* Move FromCuda trait into zluda_common

* Write some doc comments

* Fix typo

* Edit comment

* Fix formatting

Cargo.lock

@@ -1793,6 +1793,7 @@ dependencies = [
  "rustc-hash 1.1.0",
  "tempfile",
  "winapi",
+ "zluda_common",
 ]
 
 [[package]]
@@ -1825,6 +1826,14 @@ dependencies = [
  "cuda_types",
 ]
 
+[[package]]
+name = "zluda_common"
+version = "0.1.0"
+dependencies = [
+ "cuda_types",
+ "hip_runtime-sys",
+]
+
 [[package]]
 name = "zluda_dnn"
 version = "0.0.0"

Cargo.toml

@@ -21,6 +21,7 @@ members = [
     "zluda_bindgen",
     "zluda_blas",
     "zluda_blaslt",
+    "zluda_common",
     "zluda_dnn",
     "zluda_dump",
     "zluda_dump_blas",

zluda/Cargo.toml

@@ -22,6 +22,8 @@ lz4-sys = "1.9"
 tempfile = "3"
 paste = "1.0"
 rustc-hash = "1.1"
+dtor = "0.0.6"
+zluda_common = { path = "../zluda_common" }
 
 [target.'cfg(windows)'.dependencies]
 winapi = { version = "0.3", features = ["heapapi", "std"] }
@@ -34,4 +36,4 @@ dtor = "0.0.6"
 linux_symlinks = [
     "libcuda.so",
     "libcuda.so.1",
-]
+]

zluda/src/impl/context.rs

@@ -1,8 +1,9 @@
-use super::{module, FromCuda, ZludaObject};
+use super::module;
 use cuda_types::cuda::*;
 use hip_runtime_sys::*;
 use rustc_hash::{FxHashMap, FxHashSet};
 use std::{cell::RefCell, ffi::c_void, ptr, sync::Mutex};
+use zluda_common::{FromCuda, ZludaObject};
 
 thread_local! {
     pub(crate) static STACK: RefCell<Vec<(CUcontext, hipDevice_t)>> = RefCell::new(Vec::new());
@@ -48,7 +49,7 @@ impl ContextState {
         self.flags = 0;
         // drop all modules and return first error if any
         let result = self.modules.drain().fold(Ok(()), |res: CUresult, hmod| {
-            match (res, super::drop_checked::<module::Module>(hmod)) {
+            match (res, zluda_common::drop_checked::<module::Module>(hmod)) {
                 (Err(e), _) => Err(e),
                 (_, Err(e)) => Err(e),
                 _ => Ok(()),
@@ -88,6 +89,7 @@ impl Context {
 impl ZludaObject for Context {
     const COOKIE: usize = 0x5f867c6d9cb73315;
 
+    type Error = CUerror;
     type CudaHandle = CUcontext;
 
     fn drop_checked(&mut self) -> CUresult {
@@ -128,7 +130,7 @@ pub(crate) fn set_current(raw_ctx: CUcontext) -> CUresult {
             None
         })
     } else {
-        let ctx: &Context = FromCuda::from_cuda(&raw_ctx)?;
+        let ctx: &Context = FromCuda::<_, CUerror>::from_cuda(&raw_ctx)?;
         let device = ctx.device;
         STACK.with(move |stack| {
             let mut stack = stack.borrow_mut();
@@ -157,7 +159,7 @@ pub(crate) fn get_current(pctx: &mut CUcontext) -> CUresult {
 
 pub(crate) fn get_device(dev: &mut hipDevice_t) -> CUresult {
     let cu_ctx = get_current_context()?;
-    let ctx: &Context = FromCuda::from_cuda(&cu_ctx)?;
+    let ctx: &Context = FromCuda::<_, CUerror>::from_cuda(&cu_ctx)?;
     *dev = ctx.device;
     Ok(())
 }
@@ -195,7 +197,7 @@ pub(crate) unsafe fn create_v2(
 }
 
 pub(crate) unsafe fn destroy_v2(ctx: CUcontext) -> CUresult {
-    super::drop_checked::<Context>(ctx)
+    zluda_common::drop_checked::<Context>(ctx)
 }
 
 pub(crate) unsafe fn pop_current_v2(ctx: &mut CUcontext) -> CUresult {

zluda/src/impl/driver.rs

@@ -1,4 +1,3 @@
-use super::{FromCuda, LiveCheck};
 use crate::r#impl::{context, device};
 use comgr::Comgr;
 use cuda_types::cuda::*;
@@ -9,6 +8,7 @@ use std::{
     sync::OnceLock,
     usize,
 };
+use zluda_common::{FromCuda, LiveCheck};
 
 #[cfg_attr(windows, path = "os_win.rs")]
 #[cfg_attr(not(windows), path = "os_unix.rs")]
@@ -175,7 +175,7 @@ impl ::dark_api::cuda::CudaDarkApi for DarkApi {
             context::get_current(&mut current_ctx)?;
             current_ctx
         };
-        let ctx_obj: &context::Context = FromCuda::from_cuda(&_ctx)?;
+        let ctx_obj: &context::Context = FromCuda::<_, CUerror>::from_cuda(&_ctx)?;
         ctx_obj.with_state_mut(|state: &mut context::ContextState| {
             state.storage.insert(
                 key as usize,
@@ -194,7 +194,7 @@ impl ::dark_api::cuda::CudaDarkApi for DarkApi {
         cu_ctx: CUcontext,
         key: *mut c_void,
     ) -> CUresult {
-        let ctx_obj: &context::Context = FromCuda::from_cuda(&cu_ctx)?;
+        let ctx_obj: &context::Context = FromCuda::<_, CUerror>::from_cuda(&cu_ctx)?;
         ctx_obj.with_state_mut(|state: &mut context::ContextState| {
             state.storage.remove(&(key as usize));
             Ok(())
@@ -213,7 +213,7 @@ impl ::dark_api::cuda::CudaDarkApi for DarkApi {
         } else {
             _ctx = cu_ctx
         };
-        let ctx_obj: &context::Context = FromCuda::from_cuda(&_ctx)?;
+        let ctx_obj: &context::Context = FromCuda::<_, CUerror>::from_cuda(&_ctx)?;
         ctx_obj.with_state(|state: &context::ContextState| {
             match state.storage.get(&(key as usize)) {
                 Some(data) => *value = data.value as *mut c_void,

zluda/src/impl/library.rs

@@ -1,6 +1,7 @@
-use super::{module, ZludaObject};
+use super::module;
 use cuda_types::cuda::*;
 use hip_runtime_sys::*;
+use zluda_common::ZludaObject;
 
 pub(crate) struct Library {
     base: hipModule_t,
@@ -9,6 +10,7 @@ pub(crate) struct Library {
 impl ZludaObject for Library {
     const COOKIE: usize = 0xb328a916cc234d7c;
 
+    type Error = CUerror;
     type CudaHandle = CUlibrary;
 
     fn drop_checked(&mut self) -> CUresult {
@@ -35,7 +37,7 @@ pub(crate) fn load_data(
 }
 
 pub(crate) unsafe fn unload(library: CUlibrary) -> CUresult {
-    super::drop_checked::<Library>(library)
+    zluda_common::drop_checked::<Library>(library)
 }
 
 pub(crate) unsafe fn get_module(out: &mut CUmodule, library: &Library) -> CUresult {

zluda/src/impl/mod.rs

@@ -1,10 +1,5 @@
 use cuda_types::cuda::*;
-use hip_runtime_sys::*;
+use zluda_common::from_cuda_object;
-use std::{
-    ffi::CStr,
-    mem::{self, ManuallyDrop, MaybeUninit},
-    ptr,
-};
 
 pub(super) mod context;
 pub(super) mod device;
@@ -26,231 +21,4 @@ pub(crate) fn unimplemented() -> CUresult {
     CUresult::ERROR_NOT_SUPPORTED
 }
 
-pub(crate) trait FromCuda<'a, T>: Sized {
-    fn from_cuda(t: &'a T) -> Result<Self, CUerror>;
-}
-
-macro_rules! from_cuda_nop {
-    ($($type_:ty),*) => {
-        $(
-            impl<'a> FromCuda<'a, $type_> for $type_ {
-                fn from_cuda(x: &'a $type_) -> Result<Self, CUerror> {
-                    Ok(*x)
-                }
-            }
-
-            impl<'a> FromCuda<'a, *mut $type_> for &'a mut $type_ {
-                fn from_cuda(x: &'a *mut $type_) -> Result<Self, CUerror> {
-                    match unsafe { x.as_mut() } {
-                        Some(x) => Ok(x),
-                        None => Err(CUerror::INVALID_VALUE),
-                    }
-                }
-            }
-
-            impl<'a> FromCuda<'a, *const $type_> for &'a $type_ {
-                fn from_cuda(x: &'a *const $type_) -> Result<Self, CUerror> {
-                    match unsafe { x.as_ref() } {
-                        Some(x) => Ok(x),
-                        None => Err(CUerror::INVALID_VALUE),
-                    }
-                }
-            }
-
-            impl<'a> FromCuda<'a, *mut $type_> for Option<&'a mut $type_> {
-                fn from_cuda(x: &'a *mut $type_) -> Result<Self, CUerror> {
-                    Ok(unsafe { x.as_mut() })
-                }
-            }
-        )*
-    };
-}
-
-macro_rules! from_cuda_transmute {
-    ($($from:ty => $to:ty),*) => {
-        $(
-            impl<'a> FromCuda<'a, $from> for $to {
-                fn from_cuda(x: &'a $from) -> Result<Self, CUerror> {
-                    Ok(unsafe { std::mem::transmute(*x) })
-                }
-            }
-
-            impl<'a> FromCuda<'a, *mut $from> for &'a mut $to {
-                fn from_cuda(x: &'a *mut $from) -> Result<Self, CUerror> {
-                    match unsafe { x.cast::<$to>().as_mut() } {
-                        Some(x) => Ok(x),
-                        None => Err(CUerror::INVALID_VALUE),
-                    }
-                }
-            }
-
-            impl<'a> FromCuda<'a, *mut $from> for * mut $to {
-                fn from_cuda(x: &'a *mut $from) -> Result<Self, CUerror> {
-                    Ok(x.cast::<$to>())
-                }
-            }
-        )*
-    };
-}
-
-macro_rules! from_cuda_object {
-    ($($type_:ty),*) => {
-        $(
-            impl<'a> FromCuda<'a, <$type_ as ZludaObject>::CudaHandle> for <$type_ as ZludaObject>::CudaHandle {
-                fn from_cuda(handle: &'a <$type_ as ZludaObject>::CudaHandle) -> Result<<$type_ as ZludaObject>::CudaHandle, CUerror> {
-                    Ok(*handle)
-                }
-            }
-
-            impl<'a> FromCuda<'a, *mut <$type_ as ZludaObject>::CudaHandle> for &'a mut <$type_ as ZludaObject>::CudaHandle {
-                fn from_cuda(handle: &'a *mut <$type_ as ZludaObject>::CudaHandle) -> Result<&'a mut <$type_ as ZludaObject>::CudaHandle, CUerror> {
-                    match unsafe { handle.as_mut() } {
-                        Some(x) => Ok(x),
-                        None => Err(CUerror::INVALID_VALUE),
-                    }
-                }
-            }
-
-            impl<'a> FromCuda<'a, <$type_ as ZludaObject>::CudaHandle> for &'a $type_ {
-                fn from_cuda(handle: &'a <$type_ as ZludaObject>::CudaHandle) -> Result<&'a $type_, CUerror> {
-                    Ok(as_ref(handle).as_result()?)
-                }
-            }
-        )*
-    };
-}
-
-from_cuda_nop!(
-    *mut i8,
-    *mut i32,
-    *mut usize,
-    *const ::core::ffi::c_void,
-    *const ::core::ffi::c_char,
-    *mut ::core::ffi::c_void,
-    *mut *mut ::core::ffi::c_void,
-    u8,
-    i32,
-    u32,
-    u64,
-    usize,
-    cuda_types::cuda::CUdevprop,
-    CUdevice_attribute,
-    CUdriverProcAddressQueryResult,
-    CUjit_option,
-    CUlibraryOption,
-    CUmoduleLoadingMode,
-    CUuuid
-);
-from_cuda_transmute!(
-    CUuuid => hipUUID,
-    CUfunction => hipFunction_t,
-    CUfunction_attribute => hipFunction_attribute,
-    CUstream => hipStream_t,
-    CUpointer_attribute => hipPointer_attribute,
-    CUdeviceptr_v2 => hipDeviceptr_t
-);
 from_cuda_object!(module::Module, context::Context, library::Library);
-
-impl<'a> FromCuda<'a, CUlimit> for hipLimit_t {
-    fn from_cuda(limit: &'a CUlimit) -> Result<Self, CUerror> {
-        Ok(match *limit {
-            CUlimit::CU_LIMIT_STACK_SIZE => hipLimit_t::hipLimitStackSize,
-            CUlimit::CU_LIMIT_PRINTF_FIFO_SIZE => hipLimit_t::hipLimitPrintfFifoSize,
-            CUlimit::CU_LIMIT_MALLOC_HEAP_SIZE => hipLimit_t::hipLimitMallocHeapSize,
-            _ => return Err(CUerror::NOT_SUPPORTED),
-        })
-    }
-}
-
-impl<'a> FromCuda<'a, *const ::core::ffi::c_char> for &CStr {
-    fn from_cuda(s: &'a *const ::core::ffi::c_char) -> Result<Self, CUerror> {
-        if *s != ptr::null() {
-            Ok(unsafe { CStr::from_ptr(*s) })
-        } else {
-            Err(CUerror::INVALID_VALUE)
-        }
-    }
-}
-
-impl<'a> FromCuda<'a, *const ::core::ffi::c_void> for &'a ::core::ffi::c_void {
-    fn from_cuda(x: &'a *const ::core::ffi::c_void) -> Result<Self, CUerror> {
-        match unsafe { x.as_ref() } {
-            Some(x) => Ok(x),
-            None => Err(CUerror::INVALID_VALUE),
-        }
-    }
-}
-
-pub(crate) trait ZludaObject: Sized + Send + Sync {
-    const COOKIE: usize;
-    const LIVENESS_FAIL: CUerror = cuda_types::cuda::CUerror::INVALID_VALUE;
-
-    type CudaHandle: Sized;
-
-    fn drop_checked(&mut self) -> CUresult;
-
-    fn wrap(self) -> Self::CudaHandle {
-        unsafe { mem::transmute_copy(&LiveCheck::wrap(self)) }
-    }
-}
-
-#[repr(C)]
-pub(crate) struct LiveCheck<T: ZludaObject> {
-    cookie: usize,
-    data: MaybeUninit<T>,
-}
-
-impl<T: ZludaObject> LiveCheck<T> {
-    fn new(data: T) -> Self {
-        LiveCheck {
-            cookie: T::COOKIE,
-            data: MaybeUninit::new(data),
-        }
-    }
-
-    fn as_handle(&self) -> T::CudaHandle {
-        unsafe { mem::transmute_copy(&self) }
-    }
-
-    fn wrap(data: T) -> *mut Self {
-        Box::into_raw(Box::new(Self::new(data)))
-    }
-
-    fn as_result(&self) -> Result<&T, CUerror> {
-        if self.cookie == T::COOKIE {
-            Ok(unsafe { self.data.assume_init_ref() })
-        } else {
-            Err(T::LIVENESS_FAIL)
-        }
-    }
-
-    // This looks like nonsense, but it's not. There are two cases:
-    // Err(CUerror) -> meaning that the object is invalid, this pointer does not point into valid memory
-    // Ok(maybe_error) -> meaning that the object is valid, we dropped everything, but there *might*
-    //                    an error in the underlying runtime that we want to propagate
-    #[must_use]
-    fn drop_checked(&mut self) -> Result<Result<(), CUerror>, CUerror> {
-        if self.cookie == T::COOKIE {
-            self.cookie = 0;
-            let result = unsafe { self.data.assume_init_mut().drop_checked() };
-            unsafe { MaybeUninit::assume_init_drop(&mut self.data) };
-            Ok(result)
-        } else {
-            Err(T::LIVENESS_FAIL)
-        }
-    }
-}
-
-pub fn as_ref<'a, T: ZludaObject>(
-    handle: &'a T::CudaHandle,
-) -> &'a ManuallyDrop<Box<LiveCheck<T>>> {
-    unsafe { mem::transmute(handle) }
-}
-
-pub fn drop_checked<T: ZludaObject>(handle: T::CudaHandle) -> Result<(), CUerror> {
-    let mut wrapped_object: ManuallyDrop<Box<LiveCheck<T>>> =
-        unsafe { mem::transmute_copy(&handle) };
-    let underlying_error = LiveCheck::drop_checked(&mut wrapped_object)?;
-    unsafe { ManuallyDrop::drop(&mut wrapped_object) };
-    underlying_error
-}

zluda/src/impl/module.rs

@@ -1,4 +1,4 @@
-use super::{driver, ZludaObject};
+use super::driver;
 use cuda_types::{
     cuda::*,
     dark_api::{FatbinFileHeader, FatbincWrapper},
@@ -6,6 +6,7 @@ use cuda_types::{
 use dark_api::fatbin::Fatbin;
 use hip_runtime_sys::*;
 use std::{ffi::CStr, mem};
+use zluda_common::ZludaObject;
 
 pub(crate) struct Module {
     pub(crate) base: hipModule_t,
@@ -14,6 +15,7 @@ pub(crate) struct Module {
 impl ZludaObject for Module {
     const COOKIE: usize = 0xe9138bd040487d4a;
 
+    type Error = CUerror;
     type CudaHandle = CUmodule;
 
     fn drop_checked(&mut self) -> CUresult {
@@ -92,7 +94,7 @@ pub(crate) fn load_data(module: &mut CUmodule, image: &std::ffi::c_void) -> CUre
 }
 
 pub(crate) fn unload(hmod: CUmodule) -> CUresult {
-    super::drop_checked::<Module>(hmod)
+    zluda_common::drop_checked::<Module>(hmod)
 }
 
 pub(crate) fn get_function(

zluda/src/lib.rs

@@ -39,7 +39,7 @@ macro_rules! implemented {
                 if !initialized() {
                     return Err(CUerror::DEINITIALIZED);
                 }
-                cuda_macros::cuda_normalize_fn!( crate::r#impl::$fn_name ) ($(crate::r#impl::FromCuda::from_cuda(&$arg_id)?),*)?;
+                cuda_macros::cuda_normalize_fn!( crate::r#impl::$fn_name ) ($(zluda_common::FromCuda::<_, CUerror>::from_cuda(&$arg_id)?),*)?;
                 Ok(())
             }
         )*
@@ -56,7 +56,7 @@ macro_rules! implemented_in_function {
                 if !initialized() {
                     return Err(CUerror::DEINITIALIZED);
                 }
-                cuda_macros::cuda_normalize_fn!( crate::r#impl::function::$fn_name ) ($(crate::r#impl::FromCuda::from_cuda(&$arg_id)?),*)?;
+                cuda_macros::cuda_normalize_fn!( crate::r#impl::function::$fn_name ) ($(zluda_common::FromCuda::<_, CUerror>::from_cuda(&$arg_id)?),*)?;
                 Ok(())
             }
         )*

zluda_common/Cargo.toml

@@ -0,0 +1,9 @@
+[package]
+name = "zluda_common"
+version = "0.1.0"
+authors = ["Violet <c01368481@gmail.com>"]
+edition = "2021"
+
+[dependencies]
+cuda_types = { path = "../cuda_types" }
+hip_runtime-sys = { path = "../ext/hip_runtime-sys" }

zluda_common/src/lib.rs

@@ -0,0 +1,278 @@
+use cuda_types::cuda::*;
+use hip_runtime_sys::*;
+use std::{
+    ffi::CStr,
+    mem::{self, ManuallyDrop, MaybeUninit},
+    ptr,
+};
+
+pub trait CudaErrorType {
+    const INVALID_VALUE: Self;
+    const NOT_SUPPORTED: Self;
+}
+
+impl CudaErrorType for CUerror {
+    const INVALID_VALUE: Self = Self::INVALID_VALUE;
+    const NOT_SUPPORTED: Self = Self::NOT_SUPPORTED;
+}
+
+/// Used to try to convert CUDA API values into our internal representation.
+///
+/// Similar to [`TryFrom`], but we can implement this for primitive types. We also provide conversions from pointers to references.
+pub trait FromCuda<'a, T, E: CudaErrorType>: Sized {
+    /// Tries to convert to this type.
+    fn from_cuda(t: &'a T) -> Result<Self, E>;
+}
+
+macro_rules! from_cuda_nop {
+    ($($type_:ty),*) => {
+        $(
+            impl<'a, E: CudaErrorType> FromCuda<'a, $type_, E> for $type_ {
+                fn from_cuda(x: &'a $type_) -> Result<Self, E> {
+                    Ok(*x)
+                }
+            }
+
+            impl<'a, E: CudaErrorType> FromCuda<'a, *mut $type_, E> for &'a mut $type_ {
+                fn from_cuda(x: &'a *mut $type_) -> Result<Self, E> {
+                    match unsafe { x.as_mut() } {
+                        Some(x) => Ok(x),
+                        None => Err(E::INVALID_VALUE),
+                    }
+                }
+            }
+
+            impl<'a, E: CudaErrorType> FromCuda<'a, *const $type_, E> for &'a $type_ {
+                fn from_cuda(x: &'a *const $type_) -> Result<Self, E> {
+                    match unsafe { x.as_ref() } {
+                        Some(x) => Ok(x),
+                        None => Err(E::INVALID_VALUE),
+                    }
+                }
+            }
+
+            impl<'a, E: CudaErrorType> FromCuda<'a, *mut $type_, E> for Option<&'a mut $type_> {
+                fn from_cuda(x: &'a *mut $type_) -> Result<Self, E> {
+                    Ok(unsafe { x.as_mut() })
+                }
+            }
+        )*
+    };
+}
+
+macro_rules! from_cuda_transmute {
+    ($($from:ty => $to:ty),*) => {
+        $(
+            impl<'a, E: CudaErrorType> FromCuda<'a, $from, E> for $to {
+                fn from_cuda(x: &'a $from) -> Result<Self, E> {
+                    Ok(unsafe { std::mem::transmute(*x) })
+                }
+            }
+
+            impl<'a, E: CudaErrorType> FromCuda<'a, *mut $from, E> for &'a mut $to {
+                fn from_cuda(x: &'a *mut $from) -> Result<Self, E> {
+                    match unsafe { x.cast::<$to>().as_mut() } {
+                        Some(x) => Ok(x),
+                        None => Err(E::INVALID_VALUE),
+                    }
+                }
+            }
+
+            impl<'a, E: CudaErrorType> FromCuda<'a, *mut $from, E> for * mut $to {
+                fn from_cuda(x: &'a *mut $from) -> Result<Self, E> {
+                    Ok(x.cast::<$to>())
+                }
+            }
+        )*
+    };
+}
+
+/// Implement the [`FromCuda`] trait for a [`ZludaObject`].
+#[macro_export]
+macro_rules! from_cuda_object {
+    ($($type_:ty),*) => {
+        $(
+            impl<'a> zluda_common::FromCuda<'a, <$type_ as zluda_common::ZludaObject>::CudaHandle, <$type_ as zluda_common::ZludaObject>::Error> for &'a $type_ {
+                fn from_cuda(handle: &'a <$type_ as zluda_common::ZludaObject>::CudaHandle) -> Result<&'a $type_, <$type_ as zluda_common::ZludaObject>::Error> {
+                    Ok(zluda_common::as_ref(handle).as_result()?)
+                }
+            }
+        )*
+    };
+}
+
+from_cuda_nop!(
+    *mut i8,
+    *mut i32,
+    *mut usize,
+    *const ::core::ffi::c_void,
+    *const ::core::ffi::c_char,
+    *mut ::core::ffi::c_void,
+    *mut *mut ::core::ffi::c_void,
+    u8,
+    i32,
+    u32,
+    u64,
+    usize,
+    cuda_types::cuda::CUdevprop,
+    CUdevice_attribute,
+    CUdriverProcAddressQueryResult,
+    CUjit_option,
+    CUlibraryOption,
+    CUmoduleLoadingMode,
+    CUuuid,
+    CUlibrary,
+    CUmodule,
+    CUcontext
+);
+from_cuda_transmute!(
+    CUuuid => hipUUID,
+    CUfunction => hipFunction_t,
+    CUfunction_attribute => hipFunction_attribute,
+    CUstream => hipStream_t,
+    CUpointer_attribute => hipPointer_attribute,
+    CUdeviceptr_v2 => hipDeviceptr_t
+);
+
+impl<'a, E: CudaErrorType> FromCuda<'a, CUlimit, E> for hipLimit_t {
+    fn from_cuda(limit: &'a CUlimit) -> Result<Self, E> {
+        Ok(match *limit {
+            CUlimit::CU_LIMIT_STACK_SIZE => hipLimit_t::hipLimitStackSize,
+            CUlimit::CU_LIMIT_PRINTF_FIFO_SIZE => hipLimit_t::hipLimitPrintfFifoSize,
+            CUlimit::CU_LIMIT_MALLOC_HEAP_SIZE => hipLimit_t::hipLimitMallocHeapSize,
+            _ => return Err(E::NOT_SUPPORTED),
+        })
+    }
+}
+
+impl<'a, E: CudaErrorType> FromCuda<'a, *const ::core::ffi::c_char, E> for &CStr {
+    fn from_cuda(s: &'a *const ::core::ffi::c_char) -> Result<Self, E> {
+        if *s != ptr::null() {
+            Ok(unsafe { CStr::from_ptr(*s) })
+        } else {
+            Err(E::INVALID_VALUE)
+        }
+    }
+}
+
+impl<'a, E: CudaErrorType> FromCuda<'a, *const ::core::ffi::c_void, E> for &'a ::core::ffi::c_void {
+    fn from_cuda(x: &'a *const ::core::ffi::c_void) -> Result<Self, E> {
+        match unsafe { x.as_ref() } {
+            Some(x) => Ok(x),
+            None => Err(E::INVALID_VALUE),
+        }
+    }
+}
+
+/// Represents an object that can be sent across the API boundary.
+///
+/// Some CUDA calls operate on an opaque handle. For example, `cuModuleLoadData` will load a
+/// module's data and set the `module` output argument to a new `CUmodule`. Then, other functions
+/// like `cuModuleGetFunction` can take that `CUmodule` as an argument.
+pub trait ZludaObject: Sized + Send + Sync {
+    /// This is a unique identifier used by [`LiveCheck`] for runtime type and lifetime checking.
+    ///
+    /// You can generate a new one with Python:
+    ///
+    /// ```python
+    /// import random
+    /// hex(random.getrandbits(64))
+    /// ```
+    const COOKIE: usize;
+
+    /// The value of [`Self::Error`] used to represent a type check failure or use after free.
+    const LIVENESS_FAIL: Self::Error = Self::Error::INVALID_VALUE;
+
+    /// The error type that should be used. This is generally specific to the library this trait
+    /// is being implemented in – for example, a [`ZludaObject`] in `zluda` should use the
+    /// [`CUerror`] type, and a [`ZludaObject`] in `zluda_blas` should use the [`cublasStatus_t`]
+    /// type.
+    type Error: CudaErrorType;
+    /// The handle type that an object of this trait should should be wrapped as.
+    type CudaHandle: Sized;
+
+    /// Executes the destructor for this type.
+    fn drop_checked(&mut self) -> Result<(), Self::Error>;
+
+    /// Wraps an object of this trait in a [`LiveCheck`] that can be used for runtime type and
+    /// lifetime checking, and returns it as an opaque [`Self::CudaHandle`] that can be passed to
+    /// the API caller.
+    fn wrap(self) -> Self::CudaHandle {
+        unsafe { mem::transmute_copy(&LiveCheck::wrap(self)) }
+    }
+}
+
+/// Wraps a [`ZludaObject`] and provides runtime type and lifetime checking.
+///
+/// Arbitrary memory can be cast to a value of this type, and then [`LiveCheck::as_result`] can be
+/// used to get the wrapped [`ZludaObject`] value, if it is valid.
+#[repr(C)]
+pub struct LiveCheck<T: ZludaObject> {
+    cookie: usize,
+    /// The wrapped [`ZludaObject`].
+    pub data: MaybeUninit<T>,
+}
+
+impl<T: ZludaObject> LiveCheck<T> {
+    /// Wraps `data` as a valid, initialized `LiveCheck`.
+    pub fn new(data: T) -> Self {
+        LiveCheck {
+            cookie: T::COOKIE,
+            data: MaybeUninit::new(data),
+        }
+    }
+
+    /// Returns this value as an opaque `T::CudaHandle`.
+    pub fn as_handle(&self) -> T::CudaHandle {
+        unsafe { mem::transmute_copy(&self) }
+    }
+
+    fn wrap(data: T) -> *mut Self {
+        Box::into_raw(Box::new(Self::new(data)))
+    }
+
+    /// Checks if this value represents a valid and initialized value of `T` and returns it.
+    /// Returns `T::LIVENESS_FAIL` if it does not.
+    pub fn as_result(&self) -> Result<&T, T::Error> {
+        if self.cookie == T::COOKIE {
+            Ok(unsafe { self.data.assume_init_ref() })
+        } else {
+            Err(T::LIVENESS_FAIL)
+        }
+    }
+
+    // This looks like nonsense, but it's not. There are two cases:
+    // Err(CUerror) -> meaning that the object is invalid, this pointer does not point into valid memory
+    // Ok(maybe_error) -> meaning that the object is valid, we dropped everything, but there *might*
+    //                    an error in the underlying runtime that we want to propagate
+    #[must_use]
+    fn drop_checked(&mut self) -> Result<Result<(), T::Error>, T::Error> {
+        if self.cookie == T::COOKIE {
+            self.cookie = 0;
+            let result = unsafe { self.data.assume_init_mut().drop_checked() };
+            unsafe { MaybeUninit::assume_init_drop(&mut self.data) };
+            Ok(result)
+        } else {
+            Err(T::LIVENESS_FAIL)
+        }
+    }
+}
+
+/// Cast a `T::CudaHandle` reference to a [`LiveCheck`] reference, preserving the lifetime.
+pub fn as_ref<'a, T: ZludaObject>(
+    handle: &'a T::CudaHandle,
+) -> &'a ManuallyDrop<Box<LiveCheck<T>>> {
+    unsafe { mem::transmute(handle) }
+}
+
+/// Try to drop `handle`.
+///
+/// Returns an error if `handle` is not initialized, not a value of `T`, or if `T::drop_checked`
+/// returns an error.
+pub fn drop_checked<T: ZludaObject>(handle: T::CudaHandle) -> Result<(), T::Error> {
+    let mut wrapped_object: ManuallyDrop<Box<LiveCheck<T>>> =
+        unsafe { mem::transmute_copy(&handle) };
+    let underlying_error = LiveCheck::drop_checked(&mut wrapped_object)?;
+    unsafe { ManuallyDrop::drop(&mut wrapped_object) };
+    underlying_error
+}