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rewrite shim func generator with witx CoreType

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This commit is contained in:
Pat Hickey
2020-06-24 12:47:28 -07:00
parent 564b0709dd
commit 6b62b16c7d
1 changed files with 70 additions and 173 deletions
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243
crates/wiggle/wasmtime/macro/src/lib.rs
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@@ -1,6 +1,6 @@
use proc_macro::TokenStream;
use proc_macro2::{Ident, TokenStream as TokenStream2};
use quote::{format_ident, quote};
use proc_macro2::TokenStream as TokenStream2;
use quote::quote;
use syn::parse_macro_input;
use wiggle_generate::Names;
@@ -32,13 +32,6 @@ pub fn define_wasmtime_integration(args: TokenStream) -> TokenStream {
quote!( #(#modules)* ).into()
}
enum Abi {
I32,
I64,
F32,
F64,
}
fn generate_module(
module: &witx::Module,
module_conf: &ModuleConf,
@@ -67,177 +60,16 @@ fn generate_module(
}
});
let runtime = names.runtime_mod();
let target_path = &target_conf.path;
let missing_mem_err = &missing_mem_conf.err;
let module_id = names.module(&module.name);
let target_module = quote! { #target_path::#module_id };
let ctor_externs = module.funcs().map(|f| {
let name_ident = names.func(&f.name);
if let Some(func_override) = module_conf.function_override.find(&f.name.as_str()) {
let name_ident = names.func(&f.name);
quote! { let #name_ident = wasmtime::Func::wrap(store, #func_override); }
} else {
let mut shim_arg_decls = Vec::new();
let mut params = Vec::new();
let mut hostcall_args = Vec::new();
for param in f.params.iter() {
let name = names.func_param(&param.name);
// Registers a new parameter to the shim we're making with the
// given `name`, the `abi_ty` wasm type
//
// This will register a whole bunch of things:
//
// * The cranelift type for the parameter
// * Syntax to specify the actual function parameter
// * How to actually pass this argument to the host
// implementation, converting as necessary.
let mut add_param = |name: &Ident, abi_ty: Abi| {
match abi_ty {
Abi::I32 => {
params.push(quote! { types::I32 });
shim_arg_decls.push(quote! { #name: i32 });
}
Abi::I64 => {
params.push(quote! { types::I64 });
shim_arg_decls.push(quote! { #name: i64 });
}
Abi::F32 => {
params.push(quote! { types::F32 });
shim_arg_decls.push(quote! { #name: f32 });
}
Abi::F64 => {
params.push(quote! { types::F64 });
shim_arg_decls.push(quote! { #name: f64 });
}
}
hostcall_args.push(quote! { #name as _ });
};
match &*param.tref.type_() {
witx::Type::Int(e) => match e.repr {
witx::IntRepr::U64 => add_param(&name, Abi::I64),
_ => add_param(&name, Abi::I32),
},
witx::Type::Enum(e) => match e.repr {
witx::IntRepr::U64 => add_param(&name, Abi::I64),
_ => add_param(&name, Abi::I32),
},
witx::Type::Flags(f) => match f.repr {
witx::IntRepr::U64 => add_param(&name, Abi::I64),
_ => add_param(&name, Abi::I32),
},
witx::Type::Builtin(witx::BuiltinType::Char8)
| witx::Type::Builtin(witx::BuiltinType::S8)
| witx::Type::Builtin(witx::BuiltinType::U8)
| witx::Type::Builtin(witx::BuiltinType::S16)
| witx::Type::Builtin(witx::BuiltinType::U16)
| witx::Type::Builtin(witx::BuiltinType::S32)
| witx::Type::Builtin(witx::BuiltinType::U32)
| witx::Type::Builtin(witx::BuiltinType::USize) => {
add_param(&name, Abi::I32);
}
witx::Type::Builtin(witx::BuiltinType::S64)
| witx::Type::Builtin(witx::BuiltinType::U64) => {
add_param(&name, Abi::I64);
}
witx::Type::Builtin(witx::BuiltinType::F32) => {
add_param(&name, Abi::F32);
}
witx::Type::Builtin(witx::BuiltinType::F64) => {
add_param(&name, Abi::F64);
}
// strings/arrays have an extra ABI parameter for the length
// of the array passed.
witx::Type::Builtin(witx::BuiltinType::String) | witx::Type::Array(_) => {
add_param(&name, Abi::I32);
let len = format_ident!("{}_len", name);
add_param(&len, Abi::I32);
}
witx::Type::ConstPointer(_)
| witx::Type::Handle(_)
| witx::Type::Pointer(_) => {
add_param(&name, Abi::I32);
}
witx::Type::Struct(_) | witx::Type::Union(_) => {
panic!("unsupported argument type")
}
}
}
let mut results = f.results.iter();
let mut ret_ty = quote! { () };
let mut cvt_ret = quote! {};
let mut returns = Vec::new();
let mut handle_early_error = quote! { panic!("error: {:?}", e) };
// The first result is returned bare right now...
if let Some(ret) = results.next() {
handle_early_error = quote! { return e.into() };
match &*ret.tref.type_() {
// Eventually we'll want to add support for more returned
// types, but for now let's just conform to what `*.witx`
// definitions currently use.
witx::Type::Enum(e) => match e.repr {
witx::IntRepr::U16 => {
returns.push(quote! { types::I32 });
ret_ty = quote! { i32 };
cvt_ret = quote! { .into() }
}
other => panic!("unsupported ret enum repr {:?}", other),
},
other => panic!("unsupported first return {:?}", other),
}
}
// ... and all remaining results are returned via out-poiners
for result in results {
let name = format_ident!("{}", result.name.as_str());
params.push(quote! { types::I32 });
shim_arg_decls.push(quote! { #name: i32 });
hostcall_args.push(quote! { #name });
}
quote! {
let my_cx = cx.clone();
let #name_ident = wasmtime::Func::wrap(
store,
move |caller: wasmtime::Caller<'_> #(,#shim_arg_decls)*| -> #ret_ty {
unsafe {
let mem = match caller.get_export("memory") {
Some(wasmtime::Extern::Memory(m)) => m,
_ => {
log::warn!("callee does not export a memory as \"memory\"");
let e = { #missing_mem_err };
#handle_early_error
}
};
// Wiggle does not expose any methods for
// functions to re-enter the WebAssembly module,
// or expose the memory via non-wiggle mechanisms.
// Therefore, creating a new BorrowChecker at the
// root of each function invocation is correct.
let bc = #runtime::BorrowChecker::new();
let mem = #runtime::WasmtimeGuestMemory::new( mem, bc );
#target_path::#module_id::#name_ident(
&mut my_cx.borrow_mut(),
&mem,
#(#hostcall_args),*
) #cvt_ret
}
}
);
}
generate_func(&f, names, missing_mem_conf, &target_module)
}
});
@@ -295,3 +127,68 @@ contained in the `cx` parameter.",
}
}
}
fn generate_func(
func: &witx::InterfaceFunc,
names: &Names,
missing_mem_conf: &MissingMemoryConf,
target_module: &TokenStream2,
) -> TokenStream2 {
let missing_mem_err = &missing_mem_conf.err;
let name_ident = names.func(&func.name);
let coretype = func.core_type();
let arg_decls = coretype.args.iter().map(|arg| {
let name = names.func_core_arg(arg);
let atom = names.atom_type(arg.repr());
quote! { #name: #atom }
});
let arg_names = coretype.args.iter().map(|arg| names.func_core_arg(arg));
let (ret_ty, handle_early_error) = if let Some(ret) = &coretype.ret {
let ret_ty = match ret.signifies {
witx::CoreParamSignifies::Value(atom) => names.atom_type(atom),
_ => unreachable!("coretype ret should always be passed by value"),
};
(quote! { #ret_ty }, quote! { return e.into(); })
} else {
(
quote! {()},
quote! { panic!("unrecoverable error in {}: {}", stringify!(#name_ident), e) },
)
};
let runtime = names.runtime_mod();
quote! {
let my_cx = cx.clone();
let #name_ident = wasmtime::Func::wrap(
store,
move |caller: wasmtime::Caller<'_> #(,#arg_decls)*| -> #ret_ty {
unsafe {
let mem = match caller.get_export("memory") {
Some(wasmtime::Extern::Memory(m)) => m,
_ => {
log::warn!("callee does not export a memory as \"memory\"");
let e = { #missing_mem_err };
#handle_early_error
}
};
// Wiggle does not expose any methods for
// functions to re-enter the WebAssembly module,
// or expose the memory via non-wiggle mechanisms.
// Therefore, creating a new BorrowChecker at the
// root of each function invocation is correct.
let bc = #runtime::BorrowChecker::new();
let mem = #runtime::WasmtimeGuestMemory::new( mem, bc );
#target_module::#name_ident(
&mut my_cx.borrow_mut(),
&mem,
#(#arg_names),*
)
}
}
);
}
}