T0b1/wasmtime
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Remove the need to have a Store for an InstancePre (#5683)

Browse Source 
* Remove the need to have a `Store` for an `InstancePre`

This commit relaxes a requirement of the `InstancePre` API, notably its
construction via `Linker::instantiate_pre`. Previously this function
required a `Store<T>` to be present to be able to perform type-checking
on the contents of the linker, and now this requirement has been
removed.

Items stored within a linker are either a `HostFunc`, which has type
information inside of it, or an `Extern`, which doesn't have type
information inside of it. Due to the usage of `Extern` this is why a
`Store` was required during the `InstancePre` construction process, it's
used to extract the type of an `Extern`. This commit implements a
solution where the type information of an `Extern` is stored alongside
the `Extern` itself, meaning that the `InstancePre` construction process
no longer requires a `Store<T>`.

One caveat of this implementation is that some items, such as tables and
memories, technically have a "dynamic type" where during type checking
their current size is consulted to match against the minimum size
required of an import. This no longer works when using
`Linker::instantiate_pre` as the current size used is the one when it
was inserted into the linker rather than the one available at
instantiation time. It's hoped, however, that this is a relatively
esoteric use case that doesn't impact many real-world users.

Additionally note that this is an API-breaking change. Not only is the
`Store` argument removed from `Linker::instantiate_pre`, but some other
methods such as `Linker::define` grew a `Store` argument as the type
needs to be extracted when an item is inserted into a linker.

Closes #5675

* Fix the C API

* Fix benchmark compilation

* Add C API docs

* Update crates/wasmtime/src/linker.rs

Co-authored-by: Andrew Brown <andrew.brown@intel.com>

---------

Co-authored-by: Andrew Brown <andrew.brown@intel.com>
This commit is contained in:
Alex Crichton
2023-02-02 11:54:20 -06:00
committed by GitHub
parent f5f517e811
commit 63d80fc509
13 changed files with 242 additions and 224 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
crates/c-api/include/wasmtime/linker.h
View File

@@ -59,6 +59,7 @@ WASM_API_EXTERN void wasmtime_linker_allow_shadowing(wasmtime_linker_t* linker,
* \brief Defines a new item in this linker.
*
* \param linker the linker the name is being defined in.
* \param store the store that the `item` is owned by.
* \param module the module name the item is defined under.
* \param module_len the byte length of `module`
* \param name the field name the item is defined under
@@ -73,6 +74,7 @@ WASM_API_EXTERN void wasmtime_linker_allow_shadowing(wasmtime_linker_t* linker,
*/
WASM_API_EXTERN wasmtime_error_t* wasmtime_linker_define(
wasmtime_linker_t *linker,
wasmtime_context_t *store,
const char *module,
size_t module_len,
const char *name,

5
crates/c-api/src/linker.rs
View File

@@ -1,6 +1,6 @@
use crate::{
bad_utf8, handle_result, wasm_engine_t, wasm_functype_t, wasm_trap_t, wasmtime_error_t,
wasmtime_extern_t, wasmtime_module_t, CStoreContextMut,
wasmtime_extern_t, wasmtime_module_t, CStoreContext, CStoreContextMut,
};
use std::ffi::c_void;
use std::mem::MaybeUninit;
@@ -41,6 +41,7 @@ macro_rules! to_str {
#[no_mangle]
pub unsafe extern "C" fn wasmtime_linker_define(
linker: &mut wasmtime_linker_t,
store: CStoreContext<'_>,
module: *const u8,
module_len: usize,
name: *const u8,
@@ -51,7 +52,7 @@ pub unsafe extern "C" fn wasmtime_linker_define(
let module = to_str!(module, module_len);
let name = to_str!(name, name_len);
let item = item.to_extern();
handle_result(linker.define(module, name, item), |_linker| ())
handle_result(linker.define(&store, module, name, item), |_linker| ())
}
#[no_mangle]