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Refactor the internals of Func to remove layers of indirection (#1363)

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* Remove `WrappedCallable` indirection

At this point `Func` has evolved quite a bit since inception and the
`WrappedCallable` trait I don't believe is needed any longer. This
should help clean up a few entry points by having fewer traits in play.

* Remove the `Callable` trait

This commit removes the `wasmtime::Callable` trait, changing the
signature of `Func::new` to take an appropriately typed `Fn`.
Additionally the function now always takes `&Caller` like `Func::wrap`
optionally can, to empower `Func::new` to have the same capabilities of
`Func::wrap`.

* Add a test for an already-fixed issue

Closes #849

* rustfmt

* Update more locations for `Callable`

* rustfmt

* Remove a stray leading borrow

* Review feedback

* Remove unneeded `wasmtime_call_trampoline` shim
This commit is contained in:
Alex Crichton
2020-03-19 14:21:45 -05:00
committed by GitHub
parent 39ba281bc7
commit afd980b4f6
16 changed files with 354 additions and 682 deletions
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52
crates/runtime/src/traphandlers.rs
View File

@@ -3,13 +3,12 @@
use crate::instance::{InstanceHandle, SignalHandler};
use crate::trap_registry::TrapDescription;
use crate::vmcontext::{VMContext, VMFunctionBody, VMTrampoline};
use crate::vmcontext::VMContext;
use backtrace::Backtrace;
use std::any::Any;
use std::cell::Cell;
use std::error::Error;
use std::fmt;
use std::mem;
use std::ptr;
use wasmtime_environ::ir;
@@ -62,13 +61,13 @@ cfg_if::cfg_if! {
///
/// This function performs as-if a wasm trap was just executed, only the trap
/// has a dynamic payload associated with it which is user-provided. This trap
/// payload is then returned from `wasmtime_call` an `wasmtime_call_trampoline`
/// below.
/// payload is then returned from `catch_traps` below.
///
/// # Safety
///
/// Only safe to call when wasm code is on the stack, aka `wasmtime_call` or
/// `wasmtime_call_trampoline` must have been previously called.
/// Only safe to call when wasm code is on the stack, aka `catch_traps` must
/// have been previously called. Additionally no Rust destructors can be on the
/// stack. They will be skipped and not executed.
pub unsafe fn raise_user_trap(data: Box<dyn Error + Send + Sync>) -> ! {
tls::with(|info| info.unwrap().unwind_with(UnwindReason::UserTrap(data)))
}
@@ -76,13 +75,13 @@ pub unsafe fn raise_user_trap(data: Box<dyn Error + Send + Sync>) -> ! {
/// Raises a trap from inside library code immediately.
///
/// This function performs as-if a wasm trap was just executed. This trap
/// payload is then returned from `wasmtime_call` and `wasmtime_call_trampoline`
/// below.
/// payload is then returned from `catch_traps` below.
///
/// # Safety
///
/// Only safe to call when wasm code is on the stack, aka `wasmtime_call` or
/// `wasmtime_call_trampoline` must have been previously called.
/// Only safe to call when wasm code is on the stack, aka `catch_traps` must
/// have been previously called. Additionally no Rust destructors can be on the
/// stack. They will be skipped and not executed.
pub unsafe fn raise_lib_trap(trap: Trap) -> ! {
tls::with(|info| info.unwrap().unwind_with(UnwindReason::LibTrap(trap)))
}
@@ -92,8 +91,9 @@ pub unsafe fn raise_lib_trap(trap: Trap) -> ! {
///
/// # Safety
///
/// Only safe to call when wasm code is on the stack, aka `wasmtime_call` or
/// `wasmtime_call_trampoline` must have been previously called.
/// Only safe to call when wasm code is on the stack, aka `catch_traps` must
/// have been previously called. Additionally no Rust destructors can be on the
/// stack. They will be skipped and not executed.
pub unsafe fn resume_panic(payload: Box<dyn Any + Send>) -> ! {
tls::with(|info| info.unwrap().unwind_with(UnwindReason::Panic(payload)))
}
@@ -154,34 +154,6 @@ impl Trap {
}
}
/// Call the wasm function pointed to by `callee`.
///
/// * `vmctx` - the callee vmctx argument
/// * `caller_vmctx` - the caller vmctx argument
/// * `trampoline` - the jit-generated trampoline whose ABI takes 4 values, the
/// callee vmctx, the caller vmctx, the `callee` argument below, and then the
/// `values_vec` argument.
/// * `callee` - the third argument to the `trampoline` function
/// * `values_vec` - points to a buffer which holds the incoming arguments, and to
/// which the outgoing return values will be written.
///
/// Wildly unsafe because it calls raw function pointers and reads/writes raw
/// function pointers.
pub unsafe fn wasmtime_call_trampoline(
vmctx: *mut VMContext,
caller_vmctx: *mut VMContext,
trampoline: VMTrampoline,
callee: *const VMFunctionBody,
values_vec: *mut u8,
) -> Result<(), Trap> {
catch_traps(vmctx, || {
mem::transmute::<
_,
extern "C" fn(*mut VMContext, *mut VMContext, *const VMFunctionBody, *mut u8),
>(trampoline)(vmctx, caller_vmctx, callee, values_vec)
})
}
/// Catches any wasm traps that happen within the execution of `closure`,
/// returning them as a `Result`.
///