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bazel / crubit / fed64e62aa90ac962f46ad783ce1ea8e4c50a854 / . / rs_bindings_from_cc / src_code_gen.rs
blob: 00f2e322d64b7ea66b645426143d5157fb1ec711 [file] [log] [blame]
// Part of the Crubit project, under the Apache License v2.0 with LLVM
// Exceptions. See /LICENSE for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
use anyhow::{anyhow, bail, ensure, Context, Result};
use ffi_types::*;
use ir::*;
use itertools::Itertools;
use proc_macro2::{Ident, Literal, TokenStream};
use quote::format_ident;
use quote::quote;
use std::collections::{BTreeSet, HashMap, HashSet};
use std::iter::Iterator;
use std::panic::catch_unwind;
use std::process;
use token_stream_printer::{rs_tokens_to_formatted_string, tokens_to_string};
/// FFI equivalent of `Bindings`.
#[repr(C)]
pub struct FfiBindings {
rs_api: FfiU8SliceBox,
rs_api_impl: FfiU8SliceBox,
}
/// Deserializes IR from `json` and generates bindings source code.
///
/// This function panics on error.
///
/// # Safety
///
/// Expectations:
/// * function expects that param `json` is a FfiU8Slice for a valid array of
/// bytes with the given size.
/// * function expects that param `json` doesn't change during the call.
///
/// Ownership:
/// * function doesn't take ownership of (in other words it borrows) the
/// param `json`
/// * function passes ownership of the returned value to the caller
#[no_mangle]
pub unsafe extern "C" fn GenerateBindingsImpl(json: FfiU8Slice) -> FfiBindings {
catch_unwind(|| {
// It is ok to abort here.
let Bindings { rs_api, rs_api_impl } = generate_bindings(json.as_slice()).unwrap();
FfiBindings {
rs_api: FfiU8SliceBox::from_boxed_slice(rs_api.into_bytes().into_boxed_slice()),
rs_api_impl: FfiU8SliceBox::from_boxed_slice(
rs_api_impl.into_bytes().into_boxed_slice(),
),
}
})
.unwrap_or_else(|_| process::abort())
}
/// Source code for generated bindings.
struct Bindings {
// Rust source code.
rs_api: String,
// C++ source code.
rs_api_impl: String,
}
fn generate_bindings(json: &[u8]) -> Result<Bindings> {
let ir = deserialize_ir(json)?;
// The code is formatted with a non-default rustfmt configuration. Prevent
// downstream workflows from reformatting with a different configuration by
// marking the output with `@generated`. See also
// https://rust-lang.github.io/rustfmt/?version=v1.4.38&search=#format_generated_files
//
// TODO(lukasza): It would be nice to include "by $argv[0]"" in the
// @generated comment below. OTOH, `std::env::current_exe()` in our
// current build environment returns a guid-like path... :-/
//
// TODO(lukasza): Try to remove `#![rustfmt:skip]` - in theory it shouldn't
// be needed when `@generated` comment/keyword is present...
let rs_api = format!(
"// Automatically @generated Rust bindings for C++ target\n\
// {target}\n\
#![rustfmt::skip]\n\
{code}",
target = ir.current_target().0,
code = rs_tokens_to_formatted_string(generate_rs_api(&ir)?)?
);
let rs_api_impl = tokens_to_string(generate_rs_api_impl(&ir)?)?;
Ok(Bindings { rs_api, rs_api_impl })
}
/// Rust source code with attached information about how to modify the parent
/// crate.
///
/// For example, the snippet `vec![].into_raw_parts()` is not valid unless the
/// `vec_into_raw_parts` feature is enabled. So such a snippet should be
/// represented as:
///
/// ```
/// RsSnippet {
/// features: btree_set![make_rs_ident("vec_into_raw_parts")],
/// tokens: quote!{vec![].into_raw_parts()},
/// }
/// ```
#[derive(Clone, Debug)]
struct RsSnippet {
/// Rust feature flags used by this snippet.
features: BTreeSet<Ident>,
/// The snippet itself, as a token stream.
tokens: TokenStream,
}
impl From<TokenStream> for RsSnippet {
fn from(tokens: TokenStream) -> Self {
RsSnippet { features: BTreeSet::new(), tokens }
}
}
/// If we know the original C++ function is codegenned and already compatible
/// with `extern "C"` calling convention we skip creating/calling the C++ thunk
/// since we can call the original C++ directly.
fn can_skip_cc_thunk(func: &Func) -> bool {
// ## Inline functions
//
// Inline functions may not be codegenned in the C++ library since Clang doesn't
// know if Rust calls the function or not. Therefore in order to make inline
// functions callable from Rust we need to generate a C++ file that defines
// a thunk that delegates to the original inline function. When compiled,
// Clang will emit code for this thunk and Rust code will call the
// thunk when the user wants to call the original inline function.
//
// This is not great runtime-performance-wise in regular builds (inline function
// will not be inlined, there will always be a function call), but it is
// correct. ThinLTO builds will be able to see through the thunk and inline
// code across the language boundary. For non-ThinLTO builds we plan to
// implement <internal link> which removes the runtime performance overhead.
if func.is_inline {
return false;
}
// ## Virtual functions
//
// When calling virtual `A::Method()`, it's not necessarily the case that we'll
// specifically call the concrete `A::Method` impl. For example, if this is
// called on something whose dynamic type is some subclass `B` with an
// overridden `B::Method`, then we'll call that.
//
// We must reuse the C++ dynamic dispatching system. In this case, the easiest
// way to do it is by resorting to a C++ thunk, whose implementation will do
// the lookup.
//
// In terms of runtime performance, since this only occurs for virtual function
// calls, which are already slow, it may not be such a big deal. We can
// benchmark it later. :)
if let Some(meta) = &func.member_func_metadata {
if let Some(inst_meta) = &meta.instance_method_metadata {
if inst_meta.is_virtual {
return false;
}
}
}
// ## Custom calling convention requires a thunk.
//
// The thunk has the "C" calling convention, and internally can call the
// C++ function using any of the calling conventions supported by the C++
// compiler (which might not always match the set supported by Rust - e.g.,
// abi.rs doesn't contain "swiftcall" from
// clang::FunctionType::getNameForCallConv)
if !func.has_c_calling_convention {
return false;
}
true
}
/// Uniquely identifies a generated Rust function.
#[derive(Clone, Debug, PartialEq, Eq, Hash)]
struct FunctionId {
// If the function is on a trait impl, contains the name of the Self type for
// which the trait is being implemented.
self_type: Option<syn::Path>,
// Fully qualified path of the function. For functions in impl blocks, this
// includes the name of the type or trait on which the function is being
// implemented, e.g. `Default::default`.
function_path: syn::Path,
}
/// Returns the name of `func` in C++ syntax.
fn cxx_function_name(func: &Func, ir: &IR) -> Result<String> {
let record: Option<&str> = func
.member_func_metadata
.as_ref()
.map(|meta| meta.find_record(ir))
.transpose()?
.map(|r| &*r.cc_name);
let func_name = match &func.name {
UnqualifiedIdentifier::Identifier(id) => id.identifier.clone(),
UnqualifiedIdentifier::Operator(op) => op.cc_name(),
UnqualifiedIdentifier::Destructor => {
format!("~{}", record.expect("destructor must be associated with a record"))
}
UnqualifiedIdentifier::Constructor => {
record.expect("constructor must be associated with a record").to_string()
}
};
if let Some(record_name) = record {
Ok(format!("{}::{}", record_name, func_name))
} else {
Ok(func_name)
}
}
fn make_unsupported_fn(func: &Func, ir: &IR, message: impl ToString) -> Result<UnsupportedItem> {
Ok(UnsupportedItem {
name: cxx_function_name(func, ir)?,
message: message.to_string(),
source_loc: func.source_loc.clone(),
})
}
#[derive(Clone, Debug)]
enum GeneratedFunc {
None, // No explicit function needed (e.g. when deriving Drop).
Unsupported(UnsupportedItem),
Some { api_func: RsSnippet, thunk: RsSnippet, function_id: FunctionId },
}
/// Generates Rust source code for a given `Func`.
fn generate_func(func: &Func, ir: &IR) -> Result<GeneratedFunc> {
let make_unsupported_result = |msg: &str| -> Result<GeneratedFunc> {
Ok(GeneratedFunc::Unsupported(make_unsupported_fn(func, ir, msg)?))
};
let mut features = BTreeSet::new();
let mangled_name = &func.mangled_name;
let thunk_ident = thunk_ident(func);
let doc_comment = generate_doc_comment(&func.doc_comment);
let lifetime_to_name = HashMap::<LifetimeId, String>::from_iter(
func.lifetime_params.iter().map(|l| (l.id, l.name.clone())),
);
let return_type_fragment = RsTypeKind::new(&func.return_type.rs_type, ir)
.and_then(|t| t.format_as_return_type_fragment(ir, &lifetime_to_name))
.with_context(|| format!("Failed to format return type for {:?}", func))?;
let param_idents =
func.params.iter().map(|p| make_rs_ident(&p.identifier.identifier)).collect_vec();
let param_type_kinds = func
.params
.iter()
.map(|p| {
RsTypeKind::new(&p.type_.rs_type, ir).with_context(|| {
format!("Failed to process type of parameter {:?} on {:?}", p, func)
})
})
.collect::<Result<Vec<_>>>()?;
let param_types = param_type_kinds
.iter()
.map(|t| {
t.format(ir, &lifetime_to_name)
.with_context(|| format!("Failed to format parameter type {:?} on {:?}", t, func))
})
.collect::<Result<Vec<_>>>()?;
let is_unsafe = param_type_kinds.iter().any(|p| matches!(p, RsTypeKind::Pointer { .. }))
&& func.name != UnqualifiedIdentifier::Destructor;
let maybe_record: Option<&Record> =
func.member_func_metadata.as_ref().map(|meta| meta.find_record(ir)).transpose()?;
let maybe_record_name = maybe_record.map(|r| make_rs_ident(&r.rs_name));
// Find 1) the `func_name` and `impl_kind` of the API function to generate
// and 2) whether to `format_first_param_as_self` (`&self` or `&mut self`).
enum TraitName {
/// The constructor trait for !Unpin types. e.g. `CtorNew(quote! { ()
/// })` is the default constructor.
CtorNew(TokenStream),
/// An Unpin constructor trait, e.g. From or Clone.
UnpinConstructor(TokenStream),
/// Any other trait, e.g. Eq.
Other(TokenStream),
}
impl quote::ToTokens for TraitName {
fn to_tokens(&self, tokens: &mut TokenStream) {
match self {
Self::UnpinConstructor(t) | Self::Other(t) => t.to_tokens(tokens),
Self::CtorNew(args) => quote! { ctor::CtorNew < #args > }.to_tokens(tokens),
}
}
}
enum ImplKind {
/// No `impl` needed
None,
// For example, `impl SomeStruct { ... }` (`SomeStruct` based on
// func.member_func_metadata.)
Struct,
Trait {
/// For example, `SomeStruct`.
/// Note that `record_name` might *not* be from
/// `func.member_func_metadata`.
record_name: Ident,
/// For example, `quote!{ From<i32> }`.
trait_name: TraitName,
/// Where to declare lifetimes: `impl<'b>` VS `fn foo<'b>`.
declare_lifetimes: bool,
/// The generic params of trait `impl` (e.g. `<'b>`). These start
/// empty and only later are mutated into the correct value.
trait_generic_params: TokenStream,
},
}
impl ImplKind {
fn new_trait(trait_name: TraitName, record_name: Ident) -> Self {
ImplKind::Trait {
trait_name,
record_name,
declare_lifetimes: false,
trait_generic_params: quote! {},
}
}
fn new_generic_trait(trait_name: TraitName, record_name: Ident) -> Self {
ImplKind::Trait {
trait_name,
record_name,
declare_lifetimes: true,
trait_generic_params: quote! {},
}
}
}
let mut impl_kind: ImplKind;
let func_name: syn::Ident;
let format_first_param_as_self: bool;
match &func.name {
UnqualifiedIdentifier::Operator(op) if op.name == "==" => {
if param_type_kinds.len() != 2 {
bail!("Unexpected number of parameters in operator==: {:?}", func);
}
match (&param_type_kinds[0], &param_type_kinds[1]) {
(
RsTypeKind::Reference { referent: lhs, mutability: Mutability::Const, .. },
RsTypeKind::Reference { referent: rhs, mutability: Mutability::Const, .. },
) => match **lhs {
RsTypeKind::Record(lhs_record) => {
let lhs: Ident = make_rs_ident(&lhs_record.rs_name);
let rhs: TokenStream = rhs.format(ir, &lifetime_to_name)?;
format_first_param_as_self = true;
func_name = make_rs_ident("eq");
// Not using `ImplKind::new_generic_trait`, because #rhs
// should be stripped of references + because `&'a self`
// needs to have its lifetime declared next to `fn`, not
// next to `impl`.
impl_kind =
ImplKind::new_trait(TraitName::Other(quote! {PartialEq<#rhs>}), lhs);
}
_ => {
return make_unsupported_result(
"operator== where lhs doesn't refer to a record",
);
}
},
_ => {
return make_unsupported_result(
"operator== where operands are not const references",
);
}
};
}
UnqualifiedIdentifier::Operator(_) => {
return make_unsupported_result("Bindings for this kind of operator are not supported");
}
UnqualifiedIdentifier::Identifier(id) => {
func_name = make_rs_ident(&id.identifier);
match maybe_record {
None => {
impl_kind = ImplKind::None;
format_first_param_as_self = false;
}
Some(record) => {
impl_kind = ImplKind::Struct;
if func.is_instance_method() {
let first_param = param_type_kinds.first().ok_or_else(|| {
anyhow!("Missing `__this` parameter in an instance method: {:?}", func)
})?;
format_first_param_as_self = first_param.is_ref_to(record)
} else {
format_first_param_as_self = false;
}
}
};
}
UnqualifiedIdentifier::Destructor => {
// Note: to avoid double-destruction of the fields, they are all wrapped in
// ManuallyDrop in this case. See `generate_record`.
let record =
maybe_record.ok_or_else(|| anyhow!("Destructors must be member functions."))?;
if !should_implement_drop(record) {
return Ok(GeneratedFunc::None);
}
let record_name = maybe_record_name
.clone()
.ok_or_else(|| anyhow!("Destructors must be member functions."))?;
impl_kind = ImplKind::new_trait(TraitName::Other(quote! {Drop}), record_name);
func_name = make_rs_ident("drop");
format_first_param_as_self = true;
}
UnqualifiedIdentifier::Constructor => {
let member_func_metadata = func
.member_func_metadata
.as_ref()
.ok_or_else(|| anyhow!("Constructors must be member functions."))?;
let record = maybe_record
.ok_or_else(|| anyhow!("Constructors must be associated with a record."))?;
let instance_method_metadata =
member_func_metadata
.instance_method_metadata
.as_ref()
.ok_or_else(|| anyhow!("Constructors must be instance methods."))?;
if is_unsafe {
// TODO(b/216648347): Allow this outside of traits (e.g. after supporting
// translating C++ constructors into static methods in Rust).
return make_unsupported_result(
"Unsafe constructors (e.g. with no elided or explicit lifetimes) \
are intentionally not supported",
);
}
let record_name = maybe_record_name
.clone()
.ok_or_else(|| anyhow!("Constructors must be member functions."))?;
if !record.is_unpin() {
func_name = make_rs_ident("ctor_new");
format_first_param_as_self = false;
match func.params.len() {
0 => bail!("Missing `__this` parameter in a constructor: {:?}", func),
2 => {
let param_type = &param_types[1];
impl_kind = ImplKind::new_generic_trait(
TraitName::CtorNew(param_type.clone()),
record_name,
);
}
_ => {
// TODO(b/216648347): Support bindings for other constructors.
return make_unsupported_result(
"Only single-parameter constructors for T: !Unpin are supported for now",
);
}
}
} else {
match func.params.len() {
0 => bail!("Missing `__this` parameter in a constructor: {:?}", func),
1 => {
impl_kind = ImplKind::new_trait(
TraitName::UnpinConstructor(quote! {Default}),
record_name,
);
func_name = make_rs_ident("default");
format_first_param_as_self = false;
}
2 => {
// TODO(lukasza): Do something smart with move constructor.
if param_type_kinds[1].is_shared_ref_to(record) {
// Copy constructor
if should_derive_clone(record) {
return Ok(GeneratedFunc::None);
} else {
impl_kind = ImplKind::new_trait(
TraitName::UnpinConstructor(quote! {Clone}),
record_name,
);
func_name = make_rs_ident("clone");
format_first_param_as_self = true;
}
} else if !instance_method_metadata.is_explicit_ctor {
let param_type = &param_types[1];
impl_kind = ImplKind::new_generic_trait(
TraitName::UnpinConstructor(quote! {From< #param_type >}),
record_name,
);
func_name = make_rs_ident("from");
format_first_param_as_self = false;
} else {
return make_unsupported_result(
"Not yet supported type of constructor parameter",
);
}
}
_ => {
// TODO(b/216648347): Support bindings for other constructors.
return make_unsupported_result(
"More than 1 constructor parameter is not supported yet",
);
}
}
}
}
}
let api_func_def = {
// Clone params, return type, etc - we may need to mutate them in the
// API func, but we want to retain the originals for the thunk.
let mut return_type_fragment = return_type_fragment.clone();
let mut thunk_args = param_idents.iter().map(|id| quote! { #id}).collect_vec();
let mut api_params = param_idents
.iter()
.zip(param_types.iter())
.map(|(ident, type_)| quote! { #ident : #type_ })
.collect_vec();
let mut lifetimes = func.lifetime_params.iter().collect_vec();
let mut maybe_first_api_param = param_type_kinds.get(0);
if let ImplKind::Trait {
trait_name: TraitName::UnpinConstructor(..) | TraitName::CtorNew(..),
..
} = impl_kind
{
return_type_fragment = quote! { -> Self };
// Drop `__this` parameter from the public Rust API. Presence of
// element #0 is indirectly verified by a `Constructor`-related
// `match` branch a little bit above.
api_params.remove(0);
thunk_args.remove(0);
// Remove the lifetime associated with `__this`.
ensure!(
func.return_type.rs_type.is_unit_type(),
"Unexpectedly non-void return type of a constructor: {:?}",
func
);
let maybe_first_lifetime = func.params[0].type_.rs_type.lifetime_args.first();
let no_longer_needed_lifetime_id = maybe_first_lifetime
.ok_or_else(|| anyhow!("Missing lifetime on `__this` parameter: {:?}", func))?;
lifetimes.retain(|l| l.id != *no_longer_needed_lifetime_id);
if let Some(type_still_dependent_on_removed_lifetime) = param_type_kinds
.iter()
.skip(1) // Skipping `__this`
.flat_map(|t| t.lifetimes())
.find(|lifetime_id| *lifetime_id == *no_longer_needed_lifetime_id)
{
bail!(
"The lifetime of `__this` is unexpectedly also used by another \
parameter {:?} in function {:?}",
type_still_dependent_on_removed_lifetime,
func.name
);
}
// Rebind `maybe_first_api_param` to the next param after `__this`.
maybe_first_api_param = param_type_kinds.get(1);
}
if let ImplKind::Trait { trait_name: TraitName::CtorNew(..), .. } = impl_kind {
return_type_fragment = quote! { -> Self::CtorType };
}
// Change `__this: &'a SomeStruct` into `&'a self` if needed.
if format_first_param_as_self {
let first_api_param = maybe_first_api_param
.ok_or_else(|| anyhow!("No parameter to format as 'self': {:?}", func))?;
let self_decl =
first_api_param.format_as_self_param(func, ir, &lifetime_to_name).with_context(
|| format!("Failed to format as `self` param: {:?}", first_api_param),
)?;
// Presence of element #0 is verified by `ok_or_else` on
// `maybe_first_api_param` above.
api_params[0] = self_decl;
thunk_args[0] = quote! { self };
}
// TODO(b/200067242): the Pin-wrapping code doesn't know to wrap &mut
// MaybeUninit<T> in Pin if T is !Unpin. It should understand
// 'structural pinning', so that we do not need into_inner_unchecked()
// here.
let func_body = match &impl_kind {
ImplKind::Trait { trait_name: TraitName::CtorNew(..), .. } => {
quote! {
ctor::FnCtor::new(move |dest: std::pin::Pin<&mut std::mem::MaybeUninit<Self>>| {
unsafe {
crate::detail::#thunk_ident(std::pin::Pin::into_inner_unchecked(dest) #( , #thunk_args )*);
}
})
}
}
ImplKind::Trait { trait_name: TraitName::UnpinConstructor(..), .. } => {
// SAFETY: A user-defined constructor is not guaranteed to
// initialize all the fields. To make the `assume_init()` call
// below safe, the memory is zero-initialized first. This is a
// bit safer, because zero-initialized memory represents a valid
// value for the currently supported field types (this may
// change once the bindings generator starts supporting
// reference fields). TODO(b/213243309): Double-check if
// zero-initialization is desirable here.
quote! {
let mut tmp = std::mem::MaybeUninit::<Self>::zeroed();
unsafe {
crate::detail::#thunk_ident( &mut tmp #( , #thunk_args )* );
tmp.assume_init()
}
}
}
_ => {
let mut body = quote! { crate::detail::#thunk_ident( #( #thunk_args ),* ) };
// Only need to wrap everything in an `unsafe { ... }` block if
// the *whole* api function is safe.
if !is_unsafe {
body = quote! { unsafe { #body } };
}
body
}
};
let (pub_, unsafe_) = match impl_kind {
ImplKind::None | ImplKind::Struct => (
quote! { pub },
if is_unsafe {
quote! {unsafe}
} else {
quote! {}
},
),
ImplKind::Trait { .. } => {
// Currently supported bindings have no unsafe trait functions.
assert!(!is_unsafe);
(quote! {}, quote! {})
}
};
let lifetimes = lifetimes.into_iter().map(|l| format_lifetime_name(&l.name));
let fn_generic_params: TokenStream;
if let ImplKind::Trait { declare_lifetimes: true, trait_generic_params, .. } =
&mut impl_kind
{
*trait_generic_params = format_generic_params(lifetimes);
fn_generic_params = quote! {}
} else {
fn_generic_params = format_generic_params(lifetimes);
}
quote! {
#[inline(always)]
#pub_ #unsafe_ fn #func_name #fn_generic_params(
#( #api_params ),* ) #return_type_fragment {
#func_body
}
}
};
let api_func: TokenStream;
let function_id: FunctionId;
match impl_kind {
ImplKind::None => {
api_func = quote! { #doc_comment #api_func_def };
function_id = FunctionId { self_type: None, function_path: func_name.into() };
}
ImplKind::Struct => {
let record_name =
maybe_record_name.ok_or_else(|| anyhow!("Struct methods must have records"))?;
api_func = quote! { impl #record_name { #doc_comment #api_func_def } };
function_id = FunctionId {
self_type: None,
function_path: syn::parse2(quote! { #record_name :: #func_name })?,
};
}
ImplKind::Trait { trait_name, record_name, trait_generic_params, .. } => {
let extra_items;
match trait_name {
TraitName::CtorNew(..) => {
// This feature seems destined for stabilization, and makes the code
// simpler.
features.insert(make_rs_ident("type_alias_impl_trait"));
extra_items = quote! {type CtorType = impl ctor::Ctor<Output = Self>;};
}
_ => {
extra_items = quote! {};
}
};
api_func = quote! {
#doc_comment
impl #trait_generic_params #trait_name for #record_name {
#extra_items
#api_func_def
}
};
function_id = FunctionId {
self_type: Some(record_name.into()),
function_path: syn::parse2(quote! { #trait_name :: #func_name })?,
};
}
}
let thunk = {
let thunk_attr = if can_skip_cc_thunk(func) {
quote! {#[link_name = #mangled_name]}
} else {
quote! {}
};
// For constructors inject MaybeUninit into the type of `__this_` parameter.
let mut param_types = param_types;
if func.name == UnqualifiedIdentifier::Constructor {
if param_types.is_empty() || func.params.is_empty() {
bail!("Constructors should have at least one parameter (__this)");
}
param_types[0] = param_type_kinds[0]
.format_mut_ref_as_uninitialized(ir, &lifetime_to_name)
.with_context(|| {
format!(
"Failed to format `__this` param for a constructor thunk: {:?}",
func.params[0]
)
})?;
} else if func.name == UnqualifiedIdentifier::Destructor {
if param_types.is_empty() || func.params.is_empty() {
bail!("Destructors should have at least one parameter (__this)");
}
param_types[0] = param_type_kinds[0]
.format_ref_as_raw_ptr(ir, &lifetime_to_name)
.with_context(|| {
format!(
"Failed to format `__this` param for a destructor thunk: {:?}",
func.params[0]
)
})?;
}
let lifetimes = func.lifetime_params.iter().map(|l| format_lifetime_name(&l.name));
let generic_params = format_generic_params(lifetimes);
quote! {
#thunk_attr
pub(crate) fn #thunk_ident #generic_params( #( #param_idents: #param_types ),*
) #return_type_fragment ;
}
};
Ok(GeneratedFunc::Some {
api_func: RsSnippet { features, tokens: api_func },
thunk: thunk.into(),
function_id,
})
}
fn generate_doc_comment(comment: &Option<String>) -> TokenStream {
match comment {
Some(text) => {
// token_stream_printer (and rustfmt) don't put a space between /// and the doc
// comment, let's add it here so our comments are pretty.
let doc = format!(" {}", text.replace('\n', "\n "));
quote! {#[doc=#doc]}
}
None => quote! {},
}
}
fn format_generic_params<T: quote::ToTokens>(params: impl IntoIterator<Item = T>) -> TokenStream {
let mut params = params.into_iter().peekable();
if params.peek().is_none() {
quote! {}
} else {
quote! { < #( #params ),* > }
}
}
fn should_implement_drop(record: &Record) -> bool {
match record.destructor.definition {
// TODO(b/202258760): Only omit destructor if `Copy` is specified.
SpecialMemberDefinition::Trivial => false,
// TODO(b/212690698): Avoid calling into the C++ destructor (e.g. let
// Rust drive `drop`-ing) to avoid (somewhat unergonomic) ManuallyDrop
// if we can ask Rust to preserve C++ field destruction order in
// NontrivialMembers case.
SpecialMemberDefinition::NontrivialMembers => true,
// The `impl Drop` for NontrivialUserDefined needs to call into the
// user-defined destructor on C++ side.
SpecialMemberDefinition::NontrivialUserDefined => true,
// TODO(b/213516512): Today the IR doesn't contain Func entries for
// deleted functions/destructors/etc. But, maybe we should generate
// `impl Drop` in this case? With `unreachable!`? With
// `std::mem::forget`?
SpecialMemberDefinition::Deleted => false,
}
}
/// Returns whether fields of type `ty` need to be wrapped in `ManuallyDrop<T>`
/// to prevent the fields from being destructed twice (once by the C++
/// destructor calkled from the `impl Drop` of the struct and once by `drop` on
/// the Rust side).
///
/// A type is safe to destroy twice if it implements `Copy`. Fields of such
/// don't need to be wrapped in `ManuallyDrop<T>` even if the struct
/// containing the fields provides an `impl Drop` that calles into a C++
/// destructor (in addition to dropping the fields on the Rust side).
///
/// Note that it is not enough to just be `!needs_drop<T>()`: Rust only
/// guarantees that it is safe to use-after-destroy for `Copy` types. See
/// e.g. the documentation for
/// [`drop_in_place`](https://doc.rust-lang.org/std/ptr/fn.drop_in_place.html):
///
/// > if `T` is not `Copy`, using the pointed-to value after calling
/// > `drop_in_place` can cause undefined behavior
fn needs_manually_drop(ty: &ir::RsType, ir: &IR) -> Result<bool> {
let ty_implements_copy = RsTypeKind::new(ty, ir)?.implements_copy();
Ok(!ty_implements_copy)
}
/// Generates Rust source code for a given `Record` and associated assertions as
/// a tuple.
fn generate_record(record: &Record, ir: &IR) -> Result<(RsSnippet, RsSnippet)> {
let ident = make_rs_ident(&record.rs_name);
let doc_comment = generate_doc_comment(&record.doc_comment);
let field_idents =
record.fields.iter().map(|f| make_rs_ident(&f.identifier.identifier)).collect_vec();
let field_doc_coments =
record.fields.iter().map(|f| generate_doc_comment(&f.doc_comment)).collect_vec();
let mut field_copy_trait_assertions: Vec<TokenStream> = vec![];
let field_types = record
.fields
.iter()
.enumerate()
.map(|(i, f)| {
// [[no_unique_address]] fields are replaced by an unaligned block of memory
// which fills space up to the next field.
// See: docs/struct_layout
if f.is_no_unique_address {
let next_offset = if let Some(next) = record.fields.get(i + 1) {
next.offset
} else {
record.size * 8
};
let width = Literal::usize_unsuffixed((next_offset - f.offset) / 8);
return Ok(quote! {[std::mem::MaybeUninit<u8>; #width]});
}
let mut formatted = format_rs_type(&f.type_.rs_type, ir, &HashMap::new())
.with_context(|| {
format!("Failed to format type for field {:?} on record {:?}", f, record)
})?;
// TODO(b/212696226): Verify cases where ManuallyDrop<T> is skipped
// via static asserts in the generated code.
if should_implement_drop(record) {
if needs_manually_drop(&f.type_.rs_type, ir)? {
// TODO(b/212690698): Avoid (somewhat unergonomic) ManuallyDrop
// if we can ask Rust to preserve field destruction order if the
// destructor is the SpecialMemberDefinition::NontrivialMembers
// case.
formatted = quote! { std::mem::ManuallyDrop<#formatted> }
} else {
field_copy_trait_assertions.push(quote! {
const _: () = { assert_impl_all!(#formatted: Copy); };
});
}
};
Ok(formatted)
})
.collect::<Result<Vec<_>>>()?;
let field_accesses = record
.fields
.iter()
.map(|f| {
if f.access == AccessSpecifier::Public && !f.is_no_unique_address {
quote! { pub }
} else {
quote! {}
}
})
.collect_vec();
let size = record.size;
let alignment = record.alignment;
let field_offset_assertions =
record.fields.iter().zip(field_idents.iter()).map(|(field, field_ident)| {
let offset = field.offset;
quote! {
// The IR contains the offset in bits, while offset_of!()
// returns the offset in bytes, so we need to convert.
const _: () = assert!(offset_of!(#ident, #field_ident) * 8 == #offset);
}
});
// TODO(b/212696226): Generate `assert_impl_all!` or `assert_not_impl_all!`
// assertions about the `Copy` trait - this trait should be implemented
// iff `should_implement_drop(record)` is false.
let mut record_features = BTreeSet::new();
let mut assertion_features = BTreeSet::new();
// TODO(mboehme): For the time being, we're using unstable features to
// be able to use offset_of!() in static assertions. This is fine for a
// prototype, but longer-term we want to either get those features
// stabilized or find an alternative. For more details, see
// b/200120034#comment15
assertion_features.insert(make_rs_ident("const_ptr_offset_from"));
let derives = generate_derives(record);
let derives = if derives.is_empty() {
quote! {}
} else {
quote! {#[derive( #(#derives),* )]}
};
let unpin_impl = if record.is_unpin() {
quote! {}
} else {
// negative_impls are necessary for universal initialization due to Rust's
// coherence rules: PhantomPinned isn't enough to prove to Rust that a
// blanket impl that requires Unpin doesn't apply. See http://<internal link>=h.f6jp8ifzgt3n
record_features.insert(make_rs_ident("negative_impls"));
quote! {
__NEWLINE__ __NEWLINE__
impl !Unpin for #ident {}
}
};
let mut repr_attributes = vec![quote! {C}];
if record.override_alignment && record.alignment > 1 {
let alignment = Literal::usize_unsuffixed(record.alignment);
repr_attributes.push(quote! {align(#alignment)});
}
// Adjust the struct to also include base class subobjects. We use an opaque
// field because subobjects can live in the alignment of base class
// subobjects.
let base_subobjects_field = if let Some(base_size) = record.base_size {
let n = proc_macro2::Literal::usize_unsuffixed(base_size);
quote! {
__base_class_subobjects: [std::mem::MaybeUninit<u8>; #n],
}
} else {
quote! {}
};
let empty_struct_placeholder_field =
if record.fields.is_empty() && record.base_size.unwrap_or(0) == 0 {
quote! {
/// Prevent empty C++ struct being zero-size in Rust.
placeholder: std::mem::MaybeUninit<u8>,
}
} else {
quote! {}
};
let no_unique_address_accessors = cc_struct_no_unique_address_impl(record, ir)?;
let base_class_into = cc_struct_upcast_impl(record, ir)?;
let record_tokens = quote! {
#doc_comment
#derives
#[repr(#( #repr_attributes ),*)]
pub struct #ident {
#base_subobjects_field
#( #field_doc_coments #field_accesses #field_idents: #field_types, )*
#empty_struct_placeholder_field
}
#no_unique_address_accessors
#base_class_into
#unpin_impl
};
let assertion_tokens = quote! {
const _: () = assert!(std::mem::size_of::<#ident>() == #size);
const _: () = assert!(std::mem::align_of::<#ident>() == #alignment);
#( #field_offset_assertions )*
#( #field_copy_trait_assertions )*
};
Ok((
RsSnippet { features: record_features, tokens: record_tokens },
RsSnippet { features: assertion_features, tokens: assertion_tokens },
))
}
fn should_derive_clone(record: &Record) -> bool {
record.is_unpin()
&& record.copy_constructor.access == ir::AccessSpecifier::Public
&& record.copy_constructor.definition == SpecialMemberDefinition::Trivial
}
fn should_derive_copy(record: &Record) -> bool {
// TODO(b/202258760): Make `Copy` inclusion configurable.
should_derive_clone(record)
}
fn generate_derives(record: &Record) -> Vec<Ident> {
let mut derives = vec![];
if should_derive_clone(record) {
derives.push(make_rs_ident("Clone"));
}
if should_derive_copy(record) {
derives.push(make_rs_ident("Copy"));
}
derives
}
fn generate_enum(enum_: &Enum, ir: &IR) -> Result<TokenStream> {
let name = make_rs_ident(&enum_.identifier.identifier);
let underlying_type = format_rs_type(&enum_.underlying_type.rs_type, ir, &HashMap::new())?;
let enumerator_names =
enum_.enumerators.iter().map(|enumerator| make_rs_ident(&enumerator.identifier.identifier));
let enumerator_values = enum_.enumerators.iter().map(|enumerator| enumerator.value);
Ok(quote! {
#[repr(transparent)]
#[derive(Debug, PartialEq, Eq, Copy, Clone, Hash, PartialOrd, Ord)]
pub struct #name(#underlying_type);
impl #name {
#(pub const #enumerator_names: #name = #name(#enumerator_values);)*
}
impl From<#underlying_type> for #name {
fn from(value: #underlying_type) -> #name {
#name(v)
}
}
impl From<#name> for #underlying_type {
fn from(value: #name) -> #underlying_type {
v.0
}
}
})
}
fn generate_type_alias(type_alias: &TypeAlias, ir: &IR) -> Result<TokenStream> {
let ident = make_rs_ident(&type_alias.identifier.identifier);
let doc_comment = generate_doc_comment(&type_alias.doc_comment);
let underlying_type = format_rs_type(&type_alias.underlying_type.rs_type, ir, &HashMap::new())
.with_context(|| format!("Failed to format underlying type for {:?}", type_alias))?;
Ok(quote! {
#doc_comment
pub type #ident = #underlying_type;
})
}
/// Generates Rust source code for a given `UnsupportedItem`.
fn generate_unsupported(item: &UnsupportedItem) -> Result<TokenStream> {
let location = if item.source_loc.filename.is_empty() {
"<unknown location>".to_string()
} else {
// TODO(forster): The "google3" prefix should probably come from a command line
// argument.
// TODO(forster): Consider linking to the symbol instead of to the line number
// to avoid wrong links while generated files have not caught up.
format!("google3/{};l={}", &item.source_loc.filename, &item.source_loc.line)
};
let message = format!(
"{}\nError while generating bindings for item '{}':\n{}",
&location, &item.name, &item.message
);
Ok(quote! { __COMMENT__ #message })
}
/// Generates Rust source code for a given `Comment`.
fn generate_comment(comment: &Comment) -> Result<TokenStream> {
let text = &comment.text;
Ok(quote! { __COMMENT__ #text })
}
fn generate_rs_api(ir: &IR) -> Result<TokenStream> {
let mut items = vec![];
let mut thunks = vec![];
let mut assertions = vec![];
// We import nullable pointers as an Option<&T> and assume that at the ABI
// level, None is represented as a zero pointer value whereas Some is
// represented as as non-zero pointer value. This seems like a pretty safe
// assumption to make, but to provide some safeguard, assert that
// `Option<&i32>` and `&i32` have the same size.
assertions.push(quote! {
const _: () = assert!(std::mem::size_of::<Option<&i32>>() == std::mem::size_of::<&i32>());
});
// TODO(jeanpierreda): Delete has_record, either in favor of using RsSnippet, or not
// having uses. See https://chat.google.com/room/AAAAnQmj8Qs/6QbkSvWcfhA
let mut has_record = false;
let mut features = BTreeSet::new();
// For #![rustfmt::skip].
features.insert(make_rs_ident("custom_inner_attributes"));
// Identify all functions having overloads that we can't import (yet).
// TODO(b/213280424): Implement support for overloaded functions.
let mut seen_funcs = HashSet::new();
let mut overloaded_funcs = HashSet::new();
for func in ir.functions() {
if let GeneratedFunc::Some { function_id, .. } = generate_func(func, ir)? {
if !seen_funcs.insert(function_id.clone()) {
overloaded_funcs.insert(function_id);
}
}
}
for item in ir.items() {
match item {
Item::Func(func) => match generate_func(func, ir)? {
GeneratedFunc::None => (),
GeneratedFunc::Unsupported(unsupported) => {
items.push(generate_unsupported(&unsupported)?)
}
GeneratedFunc::Some { api_func, thunk, function_id } => {
if overloaded_funcs.contains(&function_id) {
items.push(generate_unsupported(&make_unsupported_fn(
func,
ir,
"Cannot generate bindings for overloaded function",
)?)?);
continue;
}
features.extend(api_func.features);
features.extend(thunk.features);
items.push(api_func.tokens);
thunks.push(thunk.tokens);
}
},
Item::Record(record) => {
if !ir.is_current_target(&record.owning_target)
&& !ir.is_stdlib_target(&record.owning_target)
{
continue;
}
let (snippet, assertions_snippet) = generate_record(record, ir)?;
features.extend(snippet.features);
features.extend(assertions_snippet.features);
items.push(snippet.tokens);
assertions.push(assertions_snippet.tokens);
has_record = true;
}
Item::Enum(enum_) => {
if !ir.is_current_target(&enum_.owning_target)
&& !ir.is_stdlib_target(&enum_.owning_target)
{
continue;
}
items.push(generate_enum(enum_, ir)?);
continue;
}
Item::TypeAlias(type_alias) => {
if !ir.is_current_target(&type_alias.owning_target)
&& !ir.is_stdlib_target(&type_alias.owning_target)
{
continue;
}
items.push(generate_type_alias(type_alias, ir)?);
}
Item::UnsupportedItem(unsupported) => items.push(generate_unsupported(unsupported)?),
Item::Comment(comment) => items.push(generate_comment(comment)?),
}
}
let mod_detail = if thunks.is_empty() {
quote! {}
} else {
quote! {
mod detail {
#[allow(unused_imports)]
use super::*;
extern "C" {
#( #thunks )*
}
}
}
};
let imports = if has_record {
quote! {
extern crate static_assertions;
use memoffset_unstable_const::offset_of;
use static_assertions::{assert_impl_all, assert_not_impl_all};
}
} else {
quote! {}
};
let features = if features.is_empty() {
quote! {}
} else {
quote! {
#![feature( #(#features),* )]
}
};
Ok(quote! {
#features __NEWLINE__
#![allow(non_camel_case_types)] __NEWLINE__
#![allow(non_snake_case)] __NEWLINE__ __NEWLINE__
#imports __NEWLINE__ __NEWLINE__
#( #items __NEWLINE__ __NEWLINE__ )*
#mod_detail __NEWLINE__ __NEWLINE__
#( #assertions __NEWLINE__ __NEWLINE__ )*
})
}
/// Makes an 'Ident' to be used in the Rust source code. Escapes Rust keywords.
fn make_rs_ident(ident: &str) -> Ident {
// TODO(https://github.com/dtolnay/syn/pull/1098): Remove the hardcoded list once syn recognizes
// 2018 and 2021 keywords.
if ["async", "await", "try", "dyn"].contains(&ident) {
return format_ident!("r#{}", ident);
}
match syn::parse_str::<syn::Ident>(ident) {
Ok(_) => format_ident!("{}", ident),
Err(_) => format_ident!("r#{}", ident),
}
}
/// Formats a C++ identifier. Does not escape C++ keywords.
fn format_cc_ident(ident: &str) -> TokenStream {
ident.parse().unwrap()
}
fn rs_type_name_for_target_and_identifier(
owning_target: &BlazeLabel,
identifier: &ir::Identifier,
ir: &IR,
) -> Result<TokenStream> {
let ident = make_rs_ident(identifier.identifier.as_str());
if ir.is_current_target(owning_target) || ir.is_stdlib_target(owning_target) {
Ok(quote! {#ident})
} else {
let owning_crate_name = owning_target.target_name()?;
// TODO(b/216587072): Remove this hacky escaping and use the import! macro once
// available
let escaped_owning_crate_name = owning_crate_name.replace('-', "_");
let owning_crate = make_rs_ident(&escaped_owning_crate_name);
Ok(quote! {#owning_crate::#ident})
}
}
#[derive(Debug, Eq, PartialEq)]
enum Mutability {
Const,
Mut,
}
impl Mutability {
fn format_for_pointer(&self) -> TokenStream {
match self {
Mutability::Mut => quote! {mut},
Mutability::Const => quote! {const},
}
}
fn format_for_reference(&self) -> TokenStream {
match self {
Mutability::Mut => quote! {mut},
Mutability::Const => quote! {},
}
}
}
// TODO(b/213947473): Instead of having a separate RsTypeKind here, consider
// changing ir::RsType into a similar `enum`, with fields that contain
// references (e.g. &'ir Record`) instead of DeclIds.
#[derive(Debug)]
enum RsTypeKind<'ir> {
Pointer { pointee: Box<RsTypeKind<'ir>>, mutability: Mutability },
Reference { referent: Box<RsTypeKind<'ir>>, mutability: Mutability, lifetime_id: LifetimeId },
FuncPtr { abi: &'ir str, return_type: Box<RsTypeKind<'ir>>, param_types: Vec<RsTypeKind<'ir>> },
Record(&'ir Record),
TypeAlias { type_alias: &'ir TypeAlias, underlying_type: Box<RsTypeKind<'ir>> },
Unit,
Other { name: &'ir str, type_args: Vec<RsTypeKind<'ir>> },
}
impl<'ir> RsTypeKind<'ir> {
pub fn new(ty: &'ir ir::RsType, ir: &'ir IR) -> Result<Self> {
// The lambdas deduplicate code needed by multiple `match` branches.
let get_type_args = || -> Result<Vec<RsTypeKind<'ir>>> {
ty.type_args.iter().map(|type_arg| RsTypeKind::<'ir>::new(type_arg, ir)).collect()
};
let get_pointee = || -> Result<Box<RsTypeKind<'ir>>> {
if ty.type_args.len() != 1 {
bail!("Missing pointee/referent type (need exactly 1 type argument): {:?}", ty);
}
Ok(Box::new(get_type_args()?.remove(0)))
};
let get_lifetime = || -> Result<LifetimeId> {
if ty.lifetime_args.len() != 1 {
bail!("Missing reference lifetime (need exactly 1 lifetime argument): {:?}", ty);
}
Ok(ty.lifetime_args[0])
};
let result = match ty.name.as_deref() {
None => {
ensure!(
ty.type_args.is_empty(),
"Type arguments on records nor type aliases are not yet supported: {:?}",
ty
);
match ir.item_for_type(ty)? {
Item::Record(record) => RsTypeKind::Record(record),
Item::TypeAlias(type_alias) => RsTypeKind::TypeAlias {
type_alias,
underlying_type: Box::new(RsTypeKind::new(
&type_alias.underlying_type.rs_type,
ir,
)?),
},
other_item => bail!("Item does not define a type: {:?}", other_item),
}
}
Some(name) => match name {
"()" => {
if !ty.type_args.is_empty() {
bail!("Unit type must not have type arguments: {:?}", ty);
}
RsTypeKind::Unit
}
"*mut" => {
RsTypeKind::Pointer { pointee: get_pointee()?, mutability: Mutability::Mut }
}
"*const" => {
RsTypeKind::Pointer { pointee: get_pointee()?, mutability: Mutability::Const }
}
"&mut" => RsTypeKind::Reference {
referent: get_pointee()?,
mutability: Mutability::Mut,
lifetime_id: get_lifetime()?,
},
"&" => RsTypeKind::Reference {
referent: get_pointee()?,
mutability: Mutability::Const,
lifetime_id: get_lifetime()?,
},
name => {
let mut type_args = get_type_args()?;
match name.strip_prefix("#funcPtr ") {
None => RsTypeKind::Other { name, type_args },
Some(abi) => {
// TODO(b/217419782): Consider enforcing `'static` lifetime.
ensure!(!type_args.is_empty(), "No return type in fn type: {:?}", ty);
RsTypeKind::FuncPtr {
abi,
return_type: Box::new(type_args.remove(type_args.len() - 1)),
param_types: type_args,
}
}
}
}
},
};
Ok(result)
}
/// Returns true if the type is known to be `Unpin`, false otherwise.
pub fn is_unpin(&self, ir: &IR) -> bool {
match self {
RsTypeKind::Record(record) => record.is_unpin(),
RsTypeKind::TypeAlias { underlying_type, .. } => underlying_type.is_unpin(ir),
_ => true,
}
}
pub fn format(
&self,
ir: &IR,
lifetime_to_name: &HashMap<LifetimeId, String>,
) -> Result<TokenStream> {
let result = match self {
RsTypeKind::Pointer { pointee, mutability } => {
let mutability = mutability.format_for_pointer();
let nested_type = pointee.format(ir, lifetime_to_name)?;
quote! {* #mutability #nested_type}
}
RsTypeKind::Reference { referent, mutability, lifetime_id } => {
let mut_ = mutability.format_for_reference();
let lifetime = Self::format_lifetime(lifetime_id, lifetime_to_name)?;
let nested_type = referent.format(ir, lifetime_to_name)?;
let reference = quote! {& #lifetime #mut_ #nested_type};
if mutability == &Mutability::Mut && !referent.is_unpin(ir) {
// TODO(b/200067242): Add a `use std::pin::Pin` to the crate, and use `Pin`.
// Probably format needs to return an RsSnippet, and RsSnippet needs a `uses`
// field.
quote! {std::pin::Pin< #reference >}
} else {
reference
}
}
RsTypeKind::FuncPtr { abi, return_type, param_types } => {
let return_frag =
return_type.format_as_return_type_fragment(ir, lifetime_to_name)?;
let param_types = param_types
.iter()
.map(|t| t.format(ir, lifetime_to_name))
.collect::<Result<Vec<_>>>()?;
quote! { extern #abi fn( #( #param_types ),* ) #return_frag }
}
RsTypeKind::Record(record) => rs_type_name_for_target_and_identifier(
&record.owning_target,
&Identifier { identifier: record.rs_name.clone() },
ir,
)?,
RsTypeKind::TypeAlias { type_alias, .. } => rs_type_name_for_target_and_identifier(
&type_alias.owning_target,
&type_alias.identifier,
ir,
)?,
RsTypeKind::Unit => quote! {()},
RsTypeKind::Other { name, type_args } => {
let ident = make_rs_ident(name);
let generic_params = format_generic_params(
type_args
.iter()
.map(|type_arg| type_arg.format(ir, lifetime_to_name))
.collect::<Result<Vec<_>>>()?,
);
quote! {#ident #generic_params}
}
};
Ok(result)
}
pub fn format_as_return_type_fragment(
&self,
ir: &IR,
lifetime_to_name: &HashMap<LifetimeId, String>,
) -> Result<TokenStream> {
match self {
RsTypeKind::Unit => Ok(quote! {}),
other_type => {
let return_type = other_type.format(ir, lifetime_to_name)?;
Ok(quote! { -> #return_type })
}
}
}
/// Formats this RsTypeKind as `&'a mut MaybeUninit<SomeStruct>`. This is
/// used to format `__this` parameter in a constructor thunk.
pub fn format_mut_ref_as_uninitialized(
&self,
ir: &IR,
lifetime_to_name: &HashMap<LifetimeId, String>,
) -> Result<TokenStream> {
match self {
RsTypeKind::Reference { referent, lifetime_id, mutability: Mutability::Mut } => {
let nested_type = referent.format(ir, lifetime_to_name)?;
let lifetime = Self::format_lifetime(lifetime_id, lifetime_to_name)?;
Ok(quote! { & #lifetime mut std::mem::MaybeUninit< #nested_type > })
}
_ => bail!("Expected reference to format as MaybeUninit, got: {:?}", self),
}
}
/// Formats a reference or pointer as a raw pointer.
pub fn format_ref_as_raw_ptr(
&self,
ir: &IR,
lifetime_to_name: &HashMap<LifetimeId, String>,
) -> Result<TokenStream> {
match self {
RsTypeKind::Reference { referent: pointee, mutability, .. }
| RsTypeKind::Pointer { pointee, mutability } => {
let nested_type = pointee.format(ir, lifetime_to_name)?;
let mut_ = mutability.format_for_pointer();
Ok(quote! { * #mut_ #nested_type })
}
_ => bail!("Expected reference to format as raw ptr, got: {:?}", self),
}
}
/// Formats this RsTypeKind as the `self` parameter: usually, `&'a self` or
/// `&'a mut self`.
///
/// If this is !Unpin, however, it uses `self: Pin<&mut Self>` instead.
pub fn format_as_self_param(
&self,
func: &Func,
ir: &IR,
lifetime_to_name: &HashMap<LifetimeId, String>,
) -> Result<TokenStream> {
if func.name == UnqualifiedIdentifier::Destructor {
let record = func
.member_func_metadata
.as_ref()
.ok_or_else(|| anyhow!("Destructors must be member functions: {:?}", func))?
.find_record(ir)?;
if self.is_mut_ptr_to(record) {
// Even in C++ it is UB to retain `this` pointer and dereference it
// after a destructor runs. Therefore it is safe to use `&self` or
// `&mut self` in Rust even if IR represents `__this` as a Rust
// pointer (e.g. when lifetime annotations are missing - lifetime
// annotations are required to represent it as a Rust reference).
return Ok(quote! { &mut self });
}
}
match self {
RsTypeKind::Reference { referent, lifetime_id, mutability } => {
let mut_ = mutability.format_for_reference();
let lifetime = Self::format_lifetime(lifetime_id, lifetime_to_name)?;
if mutability == &Mutability::Mut
&& !referent.is_unpin(ir)
&& func.name != UnqualifiedIdentifier::Destructor
{
// TODO(b/200067242): Add a `use std::pin::Pin` to the crate, and use `Pin`.
Ok(quote! {self: std::pin::Pin< & #lifetime #mut_ Self>})
} else {
Ok(quote! { & #lifetime #mut_ self })
}
}
_ => bail!("Unexpected type of `self` parameter: {:?}", self),
}
}
fn format_lifetime(
lifetime_id: &LifetimeId,
lifetime_to_name: &HashMap<LifetimeId, String>,
) -> Result<TokenStream> {
let lifetime_name = lifetime_to_name.get(lifetime_id).ok_or_else(|| {
anyhow!("`lifetime_to_name` doesn't have an entry for {:?}", lifetime_id)
})?;
Ok(format_lifetime_name(lifetime_name))
}
/// Returns whether the type represented by `self` implements the `Copy`
/// trait.
pub fn implements_copy(&self) -> bool {
// TODO(b/212696226): Verify results of `implements_copy` via static
// assertions in the generated Rust code (because incorrect results
// can silently lead to unsafe behavior).
match self {
RsTypeKind::Unit => true,
RsTypeKind::Pointer { .. } => true,
RsTypeKind::FuncPtr { .. } => true,
RsTypeKind::Reference { mutability: Mutability::Const, .. } => true,
RsTypeKind::Reference { mutability: Mutability::Mut, .. } => false,
RsTypeKind::Record(record) => should_derive_copy(record),
RsTypeKind::TypeAlias { underlying_type, .. } => underlying_type.implements_copy(),
RsTypeKind::Other { type_args, .. } => {
// All types that may appear here without `type_args` (e.g.
// primitive types like `i32`) implement `Copy`. Generic types
// that may be present here (e.g. Option<...>) are `Copy` if all
// of their `type_args` are `Copy`.
type_args.iter().all(|t| t.implements_copy())
}
}
}
pub fn is_mut_ptr_to(&self, expected_record: &Record) -> bool {
match self {
RsTypeKind::Pointer { pointee, mutability: Mutability::Mut, .. } => {
pointee.is_record(expected_record)
}
_ => false,
}
}
pub fn is_ref_to(&self, expected_record: &Record) -> bool {
match self {
RsTypeKind::Reference { referent, .. } => referent.is_record(expected_record),
_ => false,
}
}
pub fn is_shared_ref_to(&self, expected_record: &Record) -> bool {
match self {
RsTypeKind::Reference { referent, mutability: Mutability::Const, .. } => {
referent.is_record(expected_record)
}
_ => false,
}
}
pub fn is_record(&self, expected_record: &Record) -> bool {
match self {
RsTypeKind::Record(actual_record) => actual_record.id == expected_record.id,
_ => false,
}
}
/// Iterates over `self` and all the nested types (e.g. pointees, generic
/// type args, etc.) in DFS order.
pub fn dfs_iter<'ty>(&'ty self) -> impl Iterator<Item = &'ty RsTypeKind<'ir>> + '_ {
RsTypeKindIter::new(self)
}
/// Iterates over all `LifetimeId`s in `self` and in all the nested types.
/// Note that the results might contain duplicate LifetimeId values (e.g.
/// if the same LifetimeId is used in two `type_args`).
pub fn lifetimes(&self) -> impl Iterator<Item = LifetimeId> + '_ {
self.dfs_iter().filter_map(|t| match t {
RsTypeKind::Reference { lifetime_id, .. } => Some(*lifetime_id),
_ => None,
})
}
}
struct RsTypeKindIter<'ty, 'ir> {
todo: Vec<&'ty RsTypeKind<'ir>>,
}
impl<'ty, 'ir> RsTypeKindIter<'ty, 'ir> {
pub fn new(ty: &'ty RsTypeKind<'ir>) -> Self {
Self { todo: vec![ty] }
}
}
impl<'ty, 'ir> Iterator for RsTypeKindIter<'ty, 'ir> {
type Item = &'ty RsTypeKind<'ir>;
fn next(&mut self) -> Option<Self::Item> {
match self.todo.pop() {
None => None,
Some(curr) => {
match curr {
RsTypeKind::Unit | RsTypeKind::Record(_) => (),
RsTypeKind::Pointer { pointee, .. } => self.todo.push(pointee),
RsTypeKind::Reference { referent, .. } => self.todo.push(referent),
RsTypeKind::TypeAlias { underlying_type: t, .. } => self.todo.push(t),
RsTypeKind::FuncPtr { return_type, param_types, .. } => {
self.todo.push(return_type);
self.todo.extend(param_types.iter().rev());
}
RsTypeKind::Other { type_args, .. } => self.todo.extend(type_args.iter().rev()),
};
Some(curr)
}
}
}
}
fn format_lifetime_name(lifetime_name: &str) -> TokenStream {
let lifetime =
syn::Lifetime::new(&format!("'{}", lifetime_name), proc_macro2::Span::call_site());
quote! { #lifetime }
}
fn format_rs_type(
ty: &ir::RsType,
ir: &IR,
lifetime_to_name: &HashMap<LifetimeId, String>,
) -> Result<TokenStream> {
RsTypeKind::new(ty, ir)
.and_then(|kind| kind.format(ir, lifetime_to_name))
.with_context(|| format!("Failed to format Rust type {:?}", ty))
}
fn cc_type_name_for_item(item: &ir::Item) -> Result<TokenStream> {
Ok(match item {
Item::Record(record) => {
let ident = format_cc_ident(&record.cc_name);
quote! { class #ident }
}
Item::TypeAlias(type_alias) => {
let ident = format_cc_ident(&type_alias.identifier.identifier);
quote! { #ident }
}
_ => bail!("Item does not define a type: {:?}", item),
})
}
// Maps a Rust ABI [1] into a Clang attribute. See also
// `ConvertCcCallConvIntoRsApi` in importer.cc.
// [1]
// https://doc.rust-lang.org/reference/items/functions.html#extern-function-qualifier
fn format_cc_call_conv_as_clang_attribute(rs_abi: &str) -> Result<TokenStream> {
match rs_abi {
"cdecl" => Ok(quote! {}),
"fastcall" => Ok(quote! { __attribute__((fastcall)) }),
"stdcall" => Ok(quote! { __attribute__((stdcall)) }),
"thiscall" => Ok(quote! { __attribute__((thiscall)) }),
"vectorcall" => Ok(quote! { __attribute__((vectorcall)) }),
_ => bail!("Unsupported ABI: {}", rs_abi),
}
}
fn format_cc_type(ty: &ir::CcType, ir: &IR) -> Result<TokenStream> {
let const_fragment = if ty.is_const {
quote! {const}
} else {
quote! {}
};
if let Some(ref name) = ty.name {
match name.as_str() {
"*" => {
if ty.type_args.len() != 1 {
bail!("Invalid pointer type (need exactly 1 type argument): {:?}", ty);
}
assert_eq!(ty.type_args.len(), 1);
let nested_type = format_cc_type(&ty.type_args[0], ir)?;
Ok(quote! {#nested_type * #const_fragment})
}
"&" => {
if ty.type_args.len() != 1 {
bail!("Invalid reference type (need exactly 1 type argument): {:?}", ty);
}
let nested_type = format_cc_type(&ty.type_args[0], ir)?;
Ok(quote! {#nested_type &})
}
cc_type_name => match cc_type_name.strip_prefix("#funcValue ") {
None => {
if !ty.type_args.is_empty() {
bail!("Type not yet supported: {:?}", ty);
}
let idents = cc_type_name.split_whitespace().map(format_cc_ident);
Ok(quote! {#( #idents )* #const_fragment})
}
Some(abi) => match ty.type_args.split_last() {
None => bail!("funcValue type without a return type: {:?}", ty),
Some((ret_type, param_types)) => {
let ret_type = format_cc_type(ret_type, ir)?;
let param_types = param_types
.iter()
.map(|t| format_cc_type(t, ir))
.collect::<Result<Vec<_>>>()?;
let attr = format_cc_call_conv_as_clang_attribute(abi)?;
// `type_identity_t` is used below to avoid having to
// emit spiral-like syntax where some syntax elements of
// an inner type (e.g. function type as below) can
// surround syntax elements of an outer type (e.g. a
// pointer type). Compare: `int (*foo)(int, int)` VS
// `type_identity_t<int(int, int)>* foo`.
Ok(quote! { rs_api_impl_support::type_identity_t<
#ret_type ( #( #param_types ),* ) #attr
> })
}
},
},
}
} else {
let item = ir.item_for_type(ty)?;
let type_name = cc_type_name_for_item(item)?;
Ok(quote! {#const_fragment #type_name})
}
}
fn cc_struct_layout_assertion(record: &Record, ir: &IR) -> TokenStream {
if !ir.is_current_target(&record.owning_target) && !ir.is_stdlib_target(&record.owning_target) {
return quote! {};
}
let record_ident = format_cc_ident(&record.cc_name);
let size = Literal::usize_unsuffixed(record.size);
let alignment = Literal::usize_unsuffixed(record.alignment);
let field_assertions =
record.fields.iter().filter(|f| f.access == AccessSpecifier::Public).map(|field| {
let field_ident = format_cc_ident(&field.identifier.identifier);
let offset = Literal::usize_unsuffixed(field.offset);
// The IR contains the offset in bits, while C++'s offsetof()
// returns the offset in bytes, so we need to convert.
quote! {
static_assert(offsetof(class #record_ident, #field_ident) * 8 == #offset);
}
});
quote! {
static_assert(sizeof(class #record_ident) == #size);
static_assert(alignof(class #record_ident) == #alignment);
#( #field_assertions )*
}
}
// Returns the accessor functions for no_unique_address member variables.
fn cc_struct_no_unique_address_impl(record: &Record, ir: &IR) -> Result<TokenStream> {
let mut fields = vec![];
let mut types = vec![];
for field in &record.fields {
if field.access != AccessSpecifier::Public || !field.is_no_unique_address {
continue;
}
fields.push(make_rs_ident(&field.identifier.identifier));
types.push(format_rs_type(&field.type_.rs_type, ir, &HashMap::new()).with_context(
|| format!("Failed to format type for field {:?} on record {:?}", field, record),
)?)
}
if fields.is_empty() {
return Ok(quote! {});
}
let ident = make_rs_ident(&record.rs_name);
Ok(quote! {
impl #ident {
#(
pub fn #fields(&self) -> &#types {
unsafe {&* (&self.#fields as *const _ as *const #types)}
}
)*
}
})
}
/// Returns the implementation of base class conversions, for converting a type
/// to its unambiguous public base classes.
///
/// TODO(b/216195042): Implement this in terms of a supporting trait which casts
/// raw pointers. Then, we would have blanket impls for reference, pinned mut
/// reference, etc. conversion. The current version is just enough to test the
/// logic in importer.
//
// TODO(b/216195042): Should this use, like, AsRef/AsMut (and some equivalent
// for Pin)?
fn cc_struct_upcast_impl(record: &Record, ir: &IR) -> Result<TokenStream> {
let mut impls = Vec::with_capacity(record.unambiguous_public_bases.len());
for base in &record.unambiguous_public_bases {
let base_record: &Record = ir.find_decl(base.base_record_id)?.try_into()?;
if let Some(offset) = base.offset {
let offset = Literal::i64_unsuffixed(offset);
// TODO(b/216195042): Correctly handle imported records, lifetimes.
let base_name = make_rs_ident(&base_record.rs_name);
let derived_name = make_rs_ident(&record.rs_name);
impls.push(quote! {
impl<'a> From<&'a #derived_name> for &'a #base_name {
fn from(x: &'a #derived_name) -> Self {
unsafe {
&*((x as *const _ as *const u8).offset(#offset) as *const #base_name)
}
}
}
});
} else {
// TODO(b/216195042): determine offset dynamically / use a dynamic
// cast. This requires a new C++ function to be
// generated, so that we have something to call.
}
}
Ok(quote! {
#(#impls)*
})
}
fn thunk_ident(func: &Func) -> Ident {
format_ident!("__rust_thunk__{}", func.mangled_name)
}
fn generate_rs_api_impl(ir: &IR) -> Result<TokenStream> {
// This function uses quote! to generate C++ source code out of convenience.
// This is a bold idea so we have to continously evaluate if it still makes
// sense or the cost of working around differences in Rust and C++ tokens is
// greather than the value added.
//
// See rs_bindings_from_cc/
// token_stream_printer.rs for a list of supported placeholders.
let mut thunks = vec![];
for func in ir.functions() {
if can_skip_cc_thunk(func) {
continue;
}
let thunk_ident = thunk_ident(func);
let implementation_function = match &func.name {
UnqualifiedIdentifier::Operator(op) => {
let name = syn::parse_str::<TokenStream>(&op.name)?;
quote! { operator #name }
}
UnqualifiedIdentifier::Identifier(id) => {
let fn_ident = format_cc_ident(&id.identifier);
let static_method_metadata = func
.member_func_metadata
.as_ref()
.filter(|meta| meta.instance_method_metadata.is_none());
match static_method_metadata {
None => quote! {#fn_ident},
Some(meta) => {
let record_ident = format_cc_ident(&meta.find_record(ir)?.cc_name);
quote! { #record_ident :: #fn_ident }
}
}
}
// Use `destroy_at` to avoid needing to spell out the class name. Destructor identiifers
// use the name of the type itself, without namespace qualification, template
// parameters, or aliases. We do not need to use that naming scheme anywhere else in
// the bindings, and it can be difficult (impossible?) to spell in the general case. By
// using destroy_at, we avoid needing to determine or remember what the correct spelling
// is. Similar arguments apply to `construct_at`.
UnqualifiedIdentifier::Constructor => {
quote! { rs_api_impl_support::construct_at }
}
UnqualifiedIdentifier::Destructor => quote! {std::destroy_at},
};
let return_type_name = format_cc_type(&func.return_type.cc_type, ir)?;
let return_stmt = if func.return_type.cc_type.is_void() {
quote! {}
} else {
quote! { return }
};
let param_idents =
func.params.iter().map(|p| format_cc_ident(&p.identifier.identifier)).collect_vec();
let param_types = func
.params
.iter()
.map(|p| format_cc_type(&p.type_.cc_type, ir))
.collect::<Result<Vec<_>>>()?;
let needs_this_deref = match &func.member_func_metadata {
None => false,
Some(meta) => match &func.name {
UnqualifiedIdentifier::Constructor | UnqualifiedIdentifier::Destructor => false,
UnqualifiedIdentifier::Identifier(_) | UnqualifiedIdentifier::Operator(_) => {
meta.instance_method_metadata.is_some()
}
},
};
let (implementation_function, arg_expressions) = if !needs_this_deref {
(implementation_function, param_idents.clone())
} else {
let this_param = func
.params
.first()
.ok_or_else(|| anyhow!("Instance methods must have `__this` param."))?;
let this_arg = format_cc_ident(&this_param.identifier.identifier);
(
quote! { #this_arg -> #implementation_function},
param_idents.iter().skip(1).cloned().collect_vec(),
)
};
thunks.push(quote! {
extern "C" #return_type_name #thunk_ident( #( #param_types #param_idents ),* ) {
#return_stmt #implementation_function( #( #arg_expressions ),* );
}
});
}
let layout_assertions = ir.records().map(|record| cc_struct_layout_assertion(record, ir));
let mut standard_headers = <BTreeSet<Ident>>::new();
standard_headers.insert(format_ident!("memory")); // ubiquitous.
if ir.records().next().is_some() {
standard_headers.insert(format_ident!("cstddef"));
};
let mut includes = vec!["rs_bindings_from_cc/support/cxx20_backports.h"];
// In order to generate C++ thunk in all the cases Clang needs to be able to
// access declarations from public headers of the C++ library.
includes.extend(ir.used_headers().map(|i| &i.name as &str));
Ok(quote! {
#( __HASH_TOKEN__ include <#standard_headers> __NEWLINE__)*
__NEWLINE__
#( __HASH_TOKEN__ include #includes __NEWLINE__)* __NEWLINE__
__HASH_TOKEN__ pragma clang diagnostic push __NEWLINE__
// Disable Clang thread-safety-analysis warnings that would otherwise
// complain about thunks that call mutex locking functions in an unpaired way.
__HASH_TOKEN__ pragma clang diagnostic ignored "-Wthread-safety-analysis" __NEWLINE__
#( #thunks )* __NEWLINE__ __NEWLINE__
#( #layout_assertions __NEWLINE__ __NEWLINE__ )*
__NEWLINE__
__HASH_TOKEN__ pragma clang diagnostic pop __NEWLINE__
// To satisfy http://cs/symbol:devtools.metadata.Presubmit.CheckTerminatingNewline check.
__NEWLINE__
})
}
#[cfg(test)]
mod tests {
use super::*;
use anyhow::anyhow;
use ir_testing::{ir_from_cc, ir_from_cc_dependency, ir_func, ir_record, retrieve_func};
use static_assertions::{assert_impl_all, assert_not_impl_all};
use token_stream_matchers::{
assert_cc_matches, assert_cc_not_matches, assert_ir_matches, assert_rs_matches,
assert_rs_not_matches,
};
use token_stream_printer::tokens_to_string;
#[test]
fn test_disable_thread_safety_warnings() -> Result<()> {
let ir = ir_from_cc("inline void foo() {}")?;
let rs_api_impl = generate_rs_api_impl(&ir)?;
assert_cc_matches!(
rs_api_impl,
quote! {
...
__HASH_TOKEN__ pragma clang diagnostic push
__HASH_TOKEN__ pragma clang diagnostic ignored "-Wthread-safety-analysis"
...
__HASH_TOKEN__ pragma clang diagnostic pop
...
}
);
Ok(())
}
#[test]
// TODO(hlopko): Move this test to a more principled place where it can access
// `ir_testing`.
fn test_duplicate_decl_ids_err() {
let mut r1 = ir_record("R1");
r1.id = DeclId(42);
let mut r2 = ir_record("R2");
r2.id = DeclId(42);
let result = make_ir_from_items([r1.into(), r2.into()]);
assert!(result.is_err());
assert!(result.unwrap_err().to_string().contains("Duplicate decl_id found in"));
}
#[test]
fn test_simple_function() -> Result<()> {
let ir = ir_from_cc("int Add(int a, int b);")?;
let rs_api = generate_rs_api(&ir)?;
assert_rs_matches!(
rs_api,
quote! {
#[inline(always)]
pub fn Add(a: i32, b: i32) -> i32 {
unsafe { crate::detail::__rust_thunk___Z3Addii(a, b) }
}
}
);
assert_rs_matches!(
rs_api,
quote! {
mod detail {
#[allow(unused_imports)]
use super::*;
extern "C" {
#[link_name = "_Z3Addii"]
pub(crate) fn __rust_thunk___Z3Addii(a: i32, b: i32) -> i32;
}
}
}
);
assert_cc_not_matches!(generate_rs_api_impl(&ir)?, quote! {__rust_thunk___Z3Addii});
Ok(())
}
#[test]
fn test_inline_function() -> Result<()> {
let ir = ir_from_cc("inline int Add(int a, int b);")?;
let rs_api = generate_rs_api(&ir)?;
assert_rs_matches!(
rs_api,
quote! {
#[inline(always)]
pub fn Add(a: i32, b: i32) -> i32 {
unsafe { crate::detail::__rust_thunk___Z3Addii(a, b) }
}
}
);
assert_rs_matches!(
rs_api,
quote! {
mod detail {
#[allow(unused_imports)]
use super::*;
extern "C" {
pub(crate) fn __rust_thunk___Z3Addii(a: i32, b: i32) -> i32;
}
}
}
);
assert_cc_matches!(
generate_rs_api_impl(&ir)?,
quote! {
extern "C" int __rust_thunk___Z3Addii(int a, int b) {
return Add(a, b);
}
}
);
Ok(())
}
#[test]
fn test_simple_function_with_types_from_other_target() -> Result<()> {
let ir = ir_from_cc_dependency(
"inline ReturnStruct DoSomething(ParamStruct param);",
"struct ReturnStruct {}; struct ParamStruct {};",
)?;
let rs_api = generate_rs_api(&ir)?;
assert_rs_matches!(
rs_api,
quote! {
#[inline(always)]
pub fn DoSomething(param: dependency::ParamStruct)
-> dependency::ReturnStruct {
unsafe { crate::detail::__rust_thunk___Z11DoSomething11ParamStruct(param) }
}
}
);
assert_rs_matches!(
rs_api,
quote! {
mod detail {
#[allow(unused_imports)]
use super::*;
extern "C" {
pub(crate) fn __rust_thunk___Z11DoSomething11ParamStruct(param: dependency::ParamStruct)
-> dependency::ReturnStruct;
}
}}
);
assert_cc_matches!(
generate_rs_api_impl(&ir)?,
quote! {
extern "C" class ReturnStruct __rust_thunk___Z11DoSomething11ParamStruct(class ParamStruct param) {
return DoSomething(param);
}
}
);
Ok(())
}
#[test]
fn test_simple_struct() -> Result<()> {
let ir = ir_from_cc(&tokens_to_string(quote! {
struct SomeStruct final {
int public_int;
protected:
int protected_int;
private:
int private_int;
};
})?)?;
let rs_api = generate_rs_api(&ir)?;
assert_rs_matches!(
rs_api,
quote! {
#[derive(Clone, Copy)]
#[repr(C)]
pub struct SomeStruct {
pub public_int: i32,
protected_int: i32,
private_int: i32,
}
}
);
assert_rs_matches!(
rs_api,
quote! {
const _: () = assert!(std::mem::size_of::<Option<&i32>>() == std::mem::size_of::<&i32>());
const _: () = assert!(std::mem::size_of::<SomeStruct>() == 12usize);
const _: () = assert!(std::mem::align_of::<SomeStruct>() == 4usize);
const _: () = assert!(offset_of!(SomeStruct, public_int) * 8 == 0usize);
const _: () = assert!(offset_of!(SomeStruct, protected_int) * 8 == 32usize);
const _: () = assert!(offset_of!(SomeStruct, private_int) * 8 == 64usize);
}
);
let rs_api_impl = generate_rs_api_impl(&ir)?;
assert_cc_matches!(
rs_api_impl,
quote! {
extern "C" void __rust_thunk___ZN10SomeStructD1Ev(class SomeStruct * __this) {
std :: destroy_at (__this) ;
}
}
);
assert_cc_matches!(
rs_api_impl,
quote! {
static_assert(sizeof(class SomeStruct) == 12);
static_assert(alignof(class SomeStruct) == 4);
static_assert(offsetof(class SomeStruct, public_int) * 8 == 0);
}
);
Ok(())
}
#[test]
fn test_ref_to_struct_in_thunk_impls() -> Result<()> {
let ir = ir_from_cc("struct S{}; inline void foo(class S& s) {} ")?;
let rs_api_impl = generate_rs_api_impl(&ir)?;
assert_cc_matches!(
rs_api_impl,
quote! {
extern "C" void __rust_thunk___Z3fooR1S(class S& s) {
foo(s);
}
}
);
Ok(())
}
#[test]
fn test_const_ref_to_struct_in_thunk_impls() -> Result<()> {
let ir = ir_from_cc("struct S{}; inline void foo(const class S& s) {} ")?;
let rs_api_impl = generate_rs_api_impl(&ir)?;
assert_cc_matches!(
rs_api_impl,
quote! {
extern "C" void __rust_thunk___Z3fooRK1S(const class S& s) {
foo(s);
}
}
);
Ok(())
}
#[test]
fn test_unsigned_int_in_thunk_impls() -> Result<()> {
let ir = ir_from_cc("inline void foo(unsigned int i) {} ")?;
let rs_api_impl = generate_rs_api_impl(&ir)?;
assert_cc_matches!(
rs_api_impl,
quote! {
extern "C" void __rust_thunk___Z3fooj(unsigned int i) {
foo(i);
}
}
);
Ok(())
}
#[test]
fn test_record_static_methods_qualify_call_in_thunk() -> Result<()> {
let ir = ir_from_cc(&tokens_to_string(quote! {
struct SomeStruct {
static inline int some_func() { return 42; }
};
})?)?;
assert_cc_matches!(
generate_rs_api_impl(&ir)?,
quote! {
extern "C" int __rust_thunk___ZN10SomeStruct9some_funcEv() {
return SomeStruct::some_func();
}
}
);
Ok(())
}
#[test]
fn test_record_instance_methods_deref_this_in_thunk() -> Result<()> {
let ir = ir_from_cc(&tokens_to_string(quote! {
struct SomeStruct {
inline int some_func(int arg) const { return 42 + arg; }
};
})?)?;
assert_cc_matches!(
generate_rs_api_impl(&ir)?,
quote! {
extern "C" int __rust_thunk___ZNK10SomeStruct9some_funcEi(
const class SomeStruct* __this, int arg) {
return __this->some_func(arg);
}
}
);
Ok(())
}
#[test]
fn test_struct_from_other_target() -> Result<()> {
let ir = ir_from_cc_dependency("// intentionally empty", "struct SomeStruct {};")?;
assert_rs_not_matches!(generate_rs_api(&ir)?, quote! { SomeStruct });
assert_cc_not_matches!(generate_rs_api_impl(&ir)?, quote! { SomeStruct });
Ok(())
}
#[test]
fn test_copy_derives() {
let record = ir_record("S");
assert_eq!(generate_derives(&record), &["Clone", "Copy"]);
}
#[test]
fn test_copy_derives_not_is_trivial_abi() {
let mut record = ir_record("S");
record.is_trivial_abi = false;
assert_eq!(generate_derives(&record), &[""; 0]);
}
/// Even if it's trivially relocatable, !Unpin C++ type cannot be
/// cloned/copied or otherwise used by value, because values would allow
/// assignment into the Pin.
///
/// All !Unpin C++ types, not just non trivially relocatable ones, are
/// unsafe to assign in the Rust sense.
#[test]
fn test_copy_derives_not_final() {
let mut record = ir_record("S");
record.is_final = false;
assert_eq!(generate_derives(&record), &[""; 0]);
}
#[test]
fn test_copy_derives_ctor_nonpublic() {
let mut record = ir_record("S");
for access in [ir::AccessSpecifier::Protected, ir::AccessSpecifier::Private] {
record.copy_constructor.access = access;
assert_eq!(generate_derives(&record), &[""; 0]);
}
}
#[test]
fn test_copy_derives_ctor_deleted() {
let mut record = ir_record("S");
record.copy_constructor.definition = ir::SpecialMemberDefinition::Deleted;
assert_eq!(generate_derives(&record), &[""; 0]);
}
#[test]
fn test_copy_derives_ctor_nontrivial_members() {
let mut record = ir_record("S");
record.copy_constructor.definition = ir::SpecialMemberDefinition::NontrivialMembers;
assert_eq!(generate_derives(&record), &[""; 0]);
}
#[test]
fn test_copy_derives_ctor_nontrivial_self() {
let mut record = ir_record("S");
record.copy_constructor.definition = ir::SpecialMemberDefinition::NontrivialUserDefined;
assert_eq!(generate_derives(&record), &[""; 0]);
}
#[test]
fn test_ptr_func() -> Result<()> {
let ir = ir_from_cc(&tokens_to_string(quote! {
inline int* Deref(int*const* p);
})?)?;
let rs_api = generate_rs_api(&ir)?;
assert_rs_matches!(
rs_api,
quote! {
#[inline(always)]
pub unsafe fn Deref(p: *const *mut i32) -> *mut i32 {
crate::detail::__rust_thunk___Z5DerefPKPi(p)
}
}
);
assert_rs_matches!(
rs_api,
quote! {
mod detail {
#[allow(unused_imports)]
use super::*;
extern "C" {
pub(crate) fn __rust_thunk___Z5DerefPKPi(p: *const *mut i32) -> *mut i32;
}
}
}
);
assert_cc_matches!(
generate_rs_api_impl(&ir)?,
quote! {
extern "C" int* __rust_thunk___Z5DerefPKPi(int* const * p) {
return Deref(p);
}
}
);
Ok(())
}
#[test]
fn test_const_char_ptr_func() -> Result<()> {
// This is a regression test: We used to include the "const" in the name
// of the CcType, which caused a panic in the code generator
// ('"const char" is not a valid Ident').
// It's therefore important that f() is inline so that we need to
// generate a thunk for it (where we then process the CcType).
let ir = ir_from_cc(&tokens_to_string(quote! {
inline void f(const char *str);
})?)?;
let rs_api = generate_rs_api(&ir)?;
assert_rs_matches!(
rs_api,
quote! {
#[inline(always)]
pub unsafe fn f(str: *const i8) {
crate::detail::__rust_thunk___Z1fPKc(str)
}
}
);
assert_rs_matches!(
rs_api,
quote! {
extern "C" {
pub(crate) fn __rust_thunk___Z1fPKc(str: *const i8);
}
}
);
assert_cc_matches!(
generate_rs_api_impl(&ir)?,
quote! {
extern "C" void __rust_thunk___Z1fPKc(char const * str){ f(str) ; }
}
);
Ok(())
}
#[test]
fn test_func_ptr_where_params_are_primitive_types() -> Result<()> {
let ir = ir_from_cc(r#" int (*get_ptr_to_func())(float, double); "#)?;
let rs_api = generate_rs_api(&ir)?;
let rs_api_impl = generate_rs_api_impl(&ir)?;
assert_rs_matches!(
rs_api,
quote! {
#[inline(always)]
pub fn get_ptr_to_func() -> Option<extern "C" fn (f32, f64) -> i32> {
unsafe { crate::detail::__rust_thunk___Z15get_ptr_to_funcv() }
}
}
);
assert_rs_matches!(
rs_api,
quote! {
mod detail {
#[allow(unused_imports)]
use super::*;
extern "C" {
#[link_name = "_Z15get_ptr_to_funcv"]
pub(crate) fn __rust_thunk___Z15get_ptr_to_funcv()
-> Option<extern "C" fn(f32, f64) -> i32>;
}
}
}
);
// Verify that no C++ thunk got generated.
assert_cc_not_matches!(rs_api_impl, quote! { __rust_thunk___Z15get_ptr_to_funcv });
// TODO(b/217419782): Add another test for more exotic calling conventions /
// abis.
// TODO(b/217419782): Add another test for pointer to a function that
// takes/returns non-trivially-movable types by value. See also
// <internal link>
Ok(())
}
#[test]
fn test_func_ref() -> Result<()> {
let ir = ir_from_cc(r#" int (&get_ref_to_func())(float, double); "#)?;
let rs_api = generate_rs_api(&ir)?;
assert_rs_matches!(
rs_api,
quote! {
#[inline(always)]
pub fn get_ref_to_func() -> extern "C" fn (f32, f64) -> i32 {
unsafe { crate::detail::__rust_thunk___Z15get_ref_to_funcv() }
}
}
);
Ok(())
}
#[test]
fn test_func_ptr_with_non_static_lifetime() -> Result<()> {
let ir = ir_from_cc(
r#"
[[clang::annotate("lifetimes", "-> a")]]
int (*get_ptr_to_func())(float, double); "#,
)?;
let rs_api = generate_rs_api(&ir)?;
assert_rs_matches!(
rs_api,
quote! {
// Error while generating bindings for item 'get_ptr_to_func':
// Return type is not supported: Function pointers with non-'static lifetimes are not supported: int (*)(float, double)
}
);
Ok(())
}
#[test]
fn test_func_ptr_where_params_are_raw_ptrs() -> Result<()> {
let ir = ir_from_cc(r#" const int* (*get_ptr_to_func())(const int*); "#)?;
let rs_api = generate_rs_api(&ir)?;
let rs_api_impl = generate_rs_api_impl(&ir)?;
assert_rs_matches!(
rs_api,
quote! {
#[inline(always)]
pub fn get_ptr_to_func() -> Option<extern "C" fn (*const i32) -> *const i32> {
unsafe { crate::detail::__rust_thunk___Z15get_ptr_to_funcv() }
}
}
);
assert_rs_matches!(
rs_api,
quote! {
mod detail {
#[allow(unused_imports)]
use super::*;
extern "C" {
#[link_name = "_Z15get_ptr_to_funcv"]
pub(crate) fn __rust_thunk___Z15get_ptr_to_funcv()
-> Option<extern "C" fn(*const i32) -> *const i32>;
}
}
}
);
// Verify that no C++ thunk got generated.
assert_cc_not_matches!(rs_api_impl, quote! { __rust_thunk___Z15get_ptr_to_funcv });
// TODO(b/217419782): Add another test where params (and the return
// type) are references with lifetimes. Something like this:
// #pragma clang lifetime_elision
// const int& (*get_ptr_to_func())(const int&, const int&); "#)?;
// 1) Need to investigate why this fails - seeing raw pointers in Rust
// seems to indicate that no lifetimes are present at the `importer.cc`
// level. Maybe lifetime elision doesn't support this scenario? Unclear
// how to explicitly apply [[clang::annotate("lifetimes", "a, b -> a")]]
// to the _inner_ function.
// 2) It is important to have 2 reference parameters, so see if the problem
// of passing `lifetimes` by value would have been caught - see:
// cl/428079010/depot/rs_bindings_from_cc/
// importer.cc?version=s6#823
// TODO(b/217419782): Decide what to do if the C++ pointer is *not*
// annotated with a lifetime - emit `unsafe fn(...) -> ...` in that
// case?
Ok(())
}
#[test]
fn test_func_ptr_with_custom_abi() -> Result<()> {
let ir = ir_from_cc(r#" int (*get_ptr_to_func())(float, double) [[clang::vectorcall]]; "#)?;
// Verify that the test input correctly represents what we intend to
// test - we want [[clang::vectorcall]] to apply to the returned
// function pointer, but *not* apply to the `get_ptr_to_func` function.
assert_ir_matches!(
ir,
quote! {
Func(Func {
name: "get_ptr_to_func", ...
return_type: MappedType {
rs_type: RsType {
name: Some("Option"), ...
type_args: [RsType { name: Some("#funcPtr vectorcall"), ... }], ...
},
cc_type: CcType {
name: Some("*"), ...
type_args: [CcType { name: Some("#funcValue vectorcall"), ... }], ...
},
}, ...
has_c_calling_convention: true, ...
}),
}
);
// Check that the custom "vectorcall" ABI gets propagated into the
// return type (i.e. into `extern "vectorcall" fn`).
let rs_api = generate_rs_api(&ir)?;
assert_rs_matches!(
rs_api,
quote! {
#[inline(always)]
pub fn get_ptr_to_func() -> Option<extern "vectorcall" fn (f32, f64) -> i32> {
unsafe { crate::detail::__rust_thunk___Z15get_ptr_to_funcv() }
}
}
);
// The usual `extern "C"` ABI should be used for "get_ptr_to_func".
assert_rs_matches!(
rs_api,
quote! {
mod detail {
#[allow(unused_imports)]
use super::*;
extern "C" {
#[link_name = "_Z15get_ptr_to_funcv"]
pub(crate) fn __rust_thunk___Z15get_ptr_to_funcv()
-> Option<extern "vectorcall" fn(f32, f64) -> i32>;
}
}
}
);
// Verify that no C++ thunk got generated.
let rs_api_impl = generate_rs_api_impl(&ir)?;
assert_cc_not_matches!(rs_api_impl, quote! { __rust_thunk___Z15get_ptr_to_funcv });
Ok(())
}
#[test]
fn test_func_ptr_thunk() -> Result<()> {
// Using an `inline` keyword forces generation of a C++ thunk in
// `rs_api_impl` (i.e. exercises `format_cc_type` and similar code).
let ir = ir_from_cc(
r#"
int multiply(int x, int y);
inline int (*inline_get_pointer_to_function())(int, int) {
return multiply;
}
"#,
)?;
let rs_api_impl = generate_rs_api_impl(&ir)?;
assert_cc_matches!(
rs_api_impl,
quote! {
extern "C" rs_api_impl_support::type_identity_t<int(int , int)>*
__rust_thunk___Z30inline_get_pointer_to_functionv() {
return inline_get_pointer_to_function();
}
}
);
Ok(())
}
#[test]
fn test_func_ptr_with_custom_abi_thunk() -> Result<()> {
// Using an `inline` keyword forces generation of a C++ thunk in
// `rs_api_impl` (i.e. exercises `format_cc_type`,
// `format_cc_call_conv_as_clang_attribute` and similar code).
let ir = ir_from_cc(
r#"
inline int (*inline_get_ptr_to_func())(float, double) [[clang::vectorcall]];
"#,
)?;
// Verify that the test input correctly represents what we intend to
// test - we want [[clang::vectorcall]] to apply to the returned
// function pointer, but *not* apply to the `get_ptr_to_func` function.
assert_ir_matches!(
ir,
quote! {
Func(Func {
name: "inline_get_ptr_to_func", ...
return_type: MappedType {
rs_type: RsType {
name: Some("Option"), ...
type_args: [RsType { name: Some("#funcPtr vectorcall"), ... }], ...
},
cc_type: CcType {
name: Some("*"), ...
type_args: [CcType { name: Some("#funcValue vectorcall"), ... }], ...
},
}, ...
has_c_calling_convention: true, ...
}),
}
);
// This test is quite similar to `test_func_ptr_thunk` - the main
// difference is verification of the `__attribute__((vectorcall))` in
// the expected signature of the generated thunk below.
let rs_api_impl = generate_rs_api_impl(&ir)?;
assert_cc_matches!(
rs_api_impl,
quote! {
extern "C" rs_api_impl_support::type_identity_t<
int(float , double) __attribute__((vectorcall))
>* __rust_thunk___Z22inline_get_ptr_to_funcv() {
return inline_get_ptr_to_func();
}
}
);
Ok(())
}
#[test]
fn test_item_order() -> Result<()> {
let ir = ir_from_cc(
"int first_func();
struct FirstStruct {};
int second_func();
struct SecondStruct {};",
)?;
let rs_api = rs_tokens_to_formatted_string(generate_rs_api(&ir)?)?;
let idx = |s: &str| rs_api.find(s).ok_or_else(|| anyhow!("'{}' missing", s));
let f1 = idx("fn first_func")?;
let f2 = idx("fn second_func")?;
let s1 = idx("struct FirstStruct")?;
let s2 = idx("struct SecondStruct")?;
let t1 = idx("fn __rust_thunk___Z10first_funcv")?;
let t2 = idx("fn __rust_thunk___Z11second_funcv")?;
assert!(f1 < s1);
assert!(s1 < f2);
assert!(f2 < s2);
assert!(s2 < t1);
assert!(t1 < t2);
Ok(())
}
#[test]
fn test_base_class_subobject_layout() -> Result<()> {
let ir = ir_from_cc(
r#"
// We use a class here to force `Derived::z` to live inside the tail padding of `Base`.
// On the Itanium ABI, this would not happen if `Base` were a POD type.
class Base {__INT64_TYPE__ x; char y;};
struct Derived final : Base {__INT16_TYPE__ z;};
"#,
)?;
let rs_api = generate_rs_api(&ir)?;
assert_rs_matches!(
rs_api,
quote! {
#[repr(C, align(8))]
pub struct Derived {
__base_class_subobjects: [std::mem::MaybeUninit<u8>; 10],
pub z: i16,
}
}
);
Ok(())
}
/// The same as test_base_class_subobject_layout, but with multiple
/// inheritance.
#[test]
fn test_base_class_multiple_inheritance_subobject_layout() -> Result<()> {
let ir = ir_from_cc(
r#"
class Base1 {__INT64_TYPE__ x;};
class Base2 {char y;};
struct Derived final : Base1, Base2 {__INT16_TYPE__ z;};
"#,
)?;
let rs_api = generate_rs_api(&ir)?;
assert_rs_matches!(
rs_api,
quote! {
#[repr(C, align(8))]
pub struct Derived {
__base_class_subobjects: [std::mem::MaybeUninit<u8>; 10],
pub z: i16,
}
}
);
Ok(())
}
/// The same as test_base_class_subobject_layout, but with a chain of
/// inheritance.
#[test]
fn test_base_class_deep_inheritance_subobject_layout() -> Result<()> {
let ir = ir_from_cc(
r#"
class Base1 {__INT64_TYPE__ x;};
class Base2 : Base1 {char y;};
struct Derived final : Base2 {__INT16_TYPE__ z;};
"#,
)?;
let rs_api = generate_rs_api(&ir)?;
assert_rs_matches!(
rs_api,
quote! {
#[repr(C, align(8))]
pub struct Derived {
__base_class_subobjects: [std::mem::MaybeUninit<u8>; 10],
pub z: i16,
}
}
);
Ok(())
}
/// For derived classes with no data members, we can't use the offset of the
/// first member to determine the size of the base class subobjects.
#[test]
fn test_base_class_subobject_fieldless_layout() -> Result<()> {
let ir = ir_from_cc(
r#"
class Base {__INT64_TYPE__ x; char y;};
struct Derived final : Base {};
"#,
)?;
let rs_api = generate_rs_api(&ir)?;
assert_rs_matches!(
rs_api,
quote! {
#[repr(C, align(8))]
pub struct Derived {
__base_class_subobjects: [std::mem::MaybeUninit<u8>; 9],
}
}
);
Ok(())
}
#[test]
fn test_base_class_subobject_empty_fieldless() -> Result<()> {
let ir = ir_from_cc(
r#"
class Base {};
struct Derived final : Base {};
"#,
)?;
let rs_api = generate_rs_api(&ir)?;
assert_rs_matches!(
rs_api,
quote! {
#[repr(C)]
pub struct Derived {
__base_class_subobjects: [std::mem::MaybeUninit<u8>; 0],
/// Prevent empty C++ struct being zero-size in Rust.
placeholder: std::mem::MaybeUninit<u8>,
}
}
);
Ok(())
}
#[test]
fn test_base_class_subobject_empty() -> Result<()> {
let ir = ir_from_cc(
r#"
class Base {};
struct Derived final : Base {};
"#,
)?;
let rs_api = generate_rs_api(&ir)?;
assert_rs_matches!(
rs_api,
quote! {
#[repr(C)]
pub struct Derived {
__base_class_subobjects: [std::mem::MaybeUninit<u8>; 0],
/// Prevent empty C++ struct being zero-size in Rust.
placeholder: std::mem::MaybeUninit<u8>,
}
}
);
Ok(())
}
/// When a field is [[no_unique_address]], it occupies the space up to the
/// next field.
#[test]
fn test_no_unique_address() -> Result<()> {
let ir = ir_from_cc(
r#"
class Field1 {__INT64_TYPE__ x;};
class Field2 {char y;};
struct Struct final {
[[no_unique_address]] Field1 field1;
[[no_unique_address]] Field2 field2;
__INT16_TYPE__ z;
};
"#,
)?;
let rs_api = generate_rs_api(&ir)?;
assert_rs_matches!(
rs_api,
quote! {
#[derive(Clone, Copy)]
#[repr(C, align(8))]
pub struct Struct {
field1: [std::mem::MaybeUninit<u8>; 8],
field2: [std::mem::MaybeUninit<u8>; 2],
pub z: i16,
}
impl Struct {
pub fn field1(&self) -> &Field1 {
unsafe {&* (&self.field1 as *const _ as *const Field1)}
}
pub fn field2(&self) -> &Field2 {
unsafe {&* (&self.field2 as *const _ as *const Field2)}
}
}
}
);
Ok(())
}
/// When a [[no_unique_address]] field is the last one, it occupies the rest
/// of the object.
#[test]
fn test_no_unique_address_last_field() -> Result<()> {
let ir = ir_from_cc(
r#"
class Field1 {__INT64_TYPE__ x;};
class Field2 {char y;};
struct Struct final {
[[no_unique_address]] Field1 field1;
[[no_unique_address]] Field2 field2;
};
"#,
)?;
let rs_api = generate_rs_api(&ir)?;
assert_rs_matches!(
rs_api,
quote! {
#[derive(Clone, Copy)]
#[repr(C, align(8))]
pub struct Struct {
field1: [std::mem::MaybeUninit<u8>; 8],
field2: [std::mem::MaybeUninit<u8>; 8],
}
}
);
Ok(())
}
#[test]
fn test_no_unique_address_empty() -> Result<()> {
let ir = ir_from_cc(
r#"
class Field {};
struct Struct final {
[[no_unique_address]] Field field;
int x;
};
"#,
)?;
let rs_api = generate_rs_api(&ir)?;
assert_rs_matches!(
rs_api,
quote! {
#[repr(C, align(4))]
pub struct Struct {
field: [std::mem::MaybeUninit<u8>; 0],
pub x: i32,
}
}
);
Ok(())
}
#[test]
fn test_base_class_subobject_empty_last_field() -> Result<()> {
let ir = ir_from_cc(
r#"
class Field {};
struct Struct final {
[[no_unique_address]] Field field;
};
"#,
)?;
let rs_api = generate_rs_api(&ir)?;
assert_rs_matches!(
rs_api,
quote! {
#[repr(C)]
pub struct Struct {
field: [std::mem::MaybeUninit<u8>; 1],
}
}
);
Ok(())
}
#[test]
fn test_generate_enum_basic() -> Result<()> {
let ir = ir_from_cc("enum Color { kRed = 5, kBlue };")?;
let rs_api = generate_rs_api(&ir)?;
assert_rs_matches!(
rs_api,
quote! {
#[repr(transparent)]
#[derive(Debug, PartialEq, Eq, Copy, Clone, Hash, PartialOrd, Ord)]
pub struct Color(u32);
impl Color {
pub const kRed: Color = Color(5);
pub const kBlue: Color = Color(6);
}
impl From<u32> for Color {
fn from(value: u32) -> Color {
Color(v)
}
}
impl From<Color> for u32 {
fn from(value: Color) -> u32 {
v.0
}
}
}
);
Ok(())
}
#[test]
fn test_generate_scoped_enum_basic() -> Result<()> {
let ir = ir_from_cc("enum class Color { kRed = -5, kBlue };")?;
let rs_api = generate_rs_api(&ir)?;
assert_rs_matches!(
rs_api,
quote! {
#[repr(transparent)]
#[derive(Debug, PartialEq, Eq, Copy, Clone, Hash, PartialOrd, Ord)]
pub struct Color(i32);
impl Color {
pub const kRed: Color = Color(-5);
pub const kBlue: Color = Color(-4);
}
impl From<i32> for Color {
fn from(value: i32) -> Color {
Color(v)
}
}
impl From<Color> for i32 {
fn from(value: Color) -> i32 {
v.0
}
}
}
);
Ok(())
}
#[test]
fn test_generate_enum_with_64_bit_signed_vals() -> Result<()> {
let ir = ir_from_cc(
"enum Color : long { kViolet = -9223372036854775807 - 1LL, kRed = -5, kBlue, kGreen = 3, kMagenta = 9223372036854775807 };",
)?;
let rs_api = generate_rs_api(&ir)?;
assert_rs_matches!(
rs_api,
quote! {
#[repr(transparent)]
#[derive(Debug, PartialEq, Eq, Copy, Clone, Hash, PartialOrd, Ord)]
pub struct Color(i64);
impl Color {
pub const kViolet: Color = Color(-9223372036854775808);
pub const kRed: Color = Color(-5);
pub const kBlue: Color = Color(-4);
pub const kGreen: Color = Color(3);
pub const kMagenta: Color = Color(9223372036854775807);
}
impl From<i64> for Color {
fn from(value: i64) -> Color {
Color(v)
}
}
impl From<Color> for i64 {
fn from(value: Color) -> i64 {
v.0
}
}
}
);
Ok(())
}
#[test]
fn test_generate_enum_with_64_bit_unsigned_vals() -> Result<()> {
let ir = ir_from_cc(
"enum Color: unsigned long { kRed, kBlue, kLimeGreen = 18446744073709551615 };",
)?;
let rs_api = generate_rs_api(&ir)?;
assert_rs_matches!(
rs_api,
quote! {
#[repr(transparent)]
#[derive(Debug, PartialEq, Eq, Copy, Clone, Hash, PartialOrd, Ord)]
pub struct Color(u64);
impl Color {
pub const kRed: Color = Color(0);
pub const kBlue: Color = Color(1);
pub const kLimeGreen: Color = Color(18446744073709551615);
}
impl From<u64> for Color {
fn from(value: u64) -> Color {
Color(v)
}
}
impl From<Color> for u64 {
fn from(value: Color) -> u64 {
v.0
}
}
}
);
Ok(())
}
#[test]
fn test_generate_enum_with_32_bit_signed_vals() -> Result<()> {
let ir = ir_from_cc(
"enum Color { kViolet = -2147483647 - 1, kRed = -5, kBlue, kGreen = 3, kMagenta = 2147483647 };",
)?;
let rs_api = generate_rs_api(&ir)?;
assert_rs_matches!(
rs_api,
quote! {
#[repr(transparent)]
#[derive(Debug, PartialEq, Eq, Copy, Clone, Hash, PartialOrd, Ord)]
pub struct Color(i32);
impl Color {
pub const kViolet: Color = Color(-2147483648);
pub const kRed: Color = Color(-5);
pub const kBlue: Color = Color(-4);
pub const kGreen: Color = Color(3);
pub const kMagenta: Color = Color(2147483647);
}
impl From<i32> for Color {
fn from(value: i32) -> Color {
Color(v)
}
}
impl From<Color> for i32 {
fn from(value: Color) -> i32 {
v.0
}
}
}
);
Ok(())
}
#[test]
fn test_generate_enum_with_32_bit_unsigned_vals() -> Result<()> {
let ir = ir_from_cc("enum Color: unsigned int { kRed, kBlue, kLimeGreen = 4294967295 };")?;
let rs_api = generate_rs_api(&ir)?;
assert_rs_matches!(
rs_api,
quote! {
#[repr(transparent)]
#[derive(Debug, PartialEq, Eq, Copy, Clone, Hash, PartialOrd, Ord)]
pub struct Color(u32);
impl Color {
pub const kRed: Color = Color(0);
pub const kBlue: Color = Color(1);
pub const kLimeGreen: Color = Color(4294967295);
}
impl From<u32> for Color {
fn from(value: u32) -> Color {
Color(v)
}
}
impl From<Color> for u32 {
fn from(value: Color) -> u32 {
v.0
}
}
}
);
Ok(())
}
#[test]
fn test_doc_comment_func() -> Result<()> {
let ir = ir_from_cc(
"
// Doc Comment
// with two lines
int func();",
)?;
assert_rs_matches!(
generate_rs_api(&ir)?,
// leading space is intentional so there is a space between /// and the text of the
// comment
quote! {
#[doc = " Doc Comment\n with two lines"]
#[inline(always)]
pub fn func
}
);
Ok(())
}
#[test]
fn test_doc_comment_record() -> Result<()> {
let ir = ir_from_cc(
"// Doc Comment\n\
//\n\
// * with bullet\n\
struct SomeStruct final {\n\
// Field doc\n\
int field;\
};",
)?;
assert_rs_matches!(
generate_rs_api(&ir)?,
quote! {
#[doc = " Doc Comment\n \n * with bullet"]
#[derive(Clone, Copy)]
#[repr(C)]
pub struct SomeStruct {
# [doc = " Field doc"]
pub field: i32,
}
}
);
Ok(())
}
#[test]
fn test_unambiguous_public_bases() -> Result<()> {
let ir = ir_from_cc_dependency(
"
struct VirtualBase {};
struct PrivateBase {};
struct ProtectedBase {};
struct UnambiguousPublicBase {};
struct AmbiguousPublicBase {};
struct MultipleInheritance : UnambiguousPublicBase, AmbiguousPublicBase {};
struct Derived : private PrivateBase, protected ProtectedBase, MultipleInheritance, AmbiguousPublicBase, virtual VirtualBase {};
",
"",
)?;
let rs_api = generate_rs_api(&ir)?;
// TODO(b/216195042): virtual bases.
assert_rs_not_matches!(rs_api, quote! { From<&'a Derived> for &'a VirtualBase });
assert_rs_matches!(rs_api, quote! { From<&'a Derived> for &'a UnambiguousPublicBase });
assert_rs_matches!(rs_api, quote! { From<&'a Derived> for &'a MultipleInheritance });
assert_rs_not_matches!(rs_api, quote! {From<&'a Derived> for &'a PrivateBase});
assert_rs_not_matches!(rs_api, quote! {From<&'a Derived> for &'a ProtectedBase});
assert_rs_not_matches!(rs_api, quote! {From<&'a Derived> for &'a AmbiguousPublicBase});
Ok(())
}
/// Contrary to intuitions: a base class conversion is ambiguous even if the
/// ambiguity is from a private base class cast that you can't even
/// perform.
///
/// Explanation (courtesy James Dennett):
///
/// > Once upon a time, there was a rule in C++ that changing all access
/// > specifiers to "public" would not change the meaning of code.
/// > That's no longer true, but some of its effects can still be seen.
///
/// So, we need to be sure to not allow casting to privately-ambiguous
/// bases.
#[test]
fn test_unambiguous_public_bases_private_ambiguity() -> Result<()> {
let ir = ir_from_cc_dependency(
"
struct Base {};
struct Intermediate : public Base {};
struct Derived : Base, private Intermediate {};
",
"",
)?;
let rs_api = generate_rs_api(&ir)?;
assert_rs_not_matches!(rs_api, quote! { From<&'a Derived> for &'a Base });
Ok(())
}
#[test]
fn test_virtual_thunk() -> Result<()> {
let ir = ir_from_cc("struct Polymorphic { virtual void Foo(); };")?;
assert_cc_matches!(
generate_rs_api_impl(&ir)?,
quote! {
extern "C" void __rust_thunk___ZN11Polymorphic3FooEv(class Polymorphic * __this)
}
);
Ok(())
}
#[test]
fn test_custom_abi_thunk() -> Result<()> {
let ir = ir_from_cc(
r#"
float f_vectorcall_calling_convention(float p1, float p2) [[clang::vectorcall]];
double f_c_calling_convention(double p1, double p2);
"#,
)?;
let rs_api = generate_rs_api(&ir)?;
let rs_api_impl = generate_rs_api_impl(&ir)?;
assert_rs_matches!(
rs_api,
quote! {
#[inline(always)]
pub fn f_vectorcall_calling_convention(p1: f32, p2: f32) -> f32 {
unsafe {
crate::detail::__rust_thunk___Z31f_vectorcall_calling_conventionff(p1, p2)
}
}
}
);
assert_rs_matches!(
rs_api,
quote! {
#[inline(always)]
pub fn f_c_calling_convention(p1: f64, p2: f64) -> f64 {
unsafe { crate::detail::__rust_thunk___Z22f_c_calling_conventiondd(p1, p2) }
}
}
);
// `link_name` (i.e. no thunk) for `f_c_calling_convention`. No
// `link_name` (i.e. indicates presence of a thunk) for
// `f_vectorcall_calling_convention`.
assert_rs_matches!(
rs_api,
quote! {
mod detail {
#[allow(unused_imports)]
use super::*;
extern "C" {
pub(crate) fn __rust_thunk___Z31f_vectorcall_calling_conventionff(
p1: f32, p2: f32) -> f32;
#[link_name = "_Z22f_c_calling_conventiondd"]
pub(crate) fn __rust_thunk___Z22f_c_calling_conventiondd(
p1: f64, p2: f64) -> f64;
}
}
}
);
// C++ thunk needed for `f_vectorcall_calling_convention`.
assert_cc_matches!(
rs_api_impl,
quote! {
extern "C" float __rust_thunk___Z31f_vectorcall_calling_conventionff(
float p1, float p2) {
return f_vectorcall_calling_convention (p1 , p2);
}
}
);
// No C++ thunk expected for `f_c_calling_convention`.
assert_cc_not_matches!(rs_api_impl, quote! { f_c_calling_convention });
Ok(())
}
/// A trivially relocatable final struct is safe to use in Rust as normal,
/// and is Unpin.
#[test]
fn test_no_negative_impl_unpin() -> Result<()> {
let ir = ir_from_cc("struct Trivial final {};")?;
let rs_api = generate_rs_api(&ir)?;
assert_rs_not_matches!(rs_api, quote! {impl !Unpin});
Ok(())
}
/// A non-final struct, even if it's trivial, is not usable by mut
/// reference, and so is !Unpin.
#[test]
fn test_negative_impl_unpin_nonfinal() -> Result<()> {
let ir = ir_from_cc("struct Nonfinal {};")?;
let rs_api = generate_rs_api(&ir)?;
assert_rs_matches!(rs_api, quote! {impl !Unpin for Nonfinal {}});
Ok(())
}
/// At the least, a trivial type should have no drop impl if or until we add
/// empty drop impls.
#[test]
fn test_no_impl_drop() -> Result<()> {
let ir = ir_from_cc("struct Trivial {};")?;
let rs_api = rs_tokens_to_formatted_string(generate_rs_api(&ir)?)?;
assert!(!rs_api.contains("impl Drop"));
Ok(())
}
/// User-defined destructors *must* become Drop impls with ManuallyDrop
/// fields
#[test]
fn test_impl_drop_user_defined_destructor() -> Result<()> {
let ir = ir_from_cc(
r#" struct NontrivialStruct { ~NontrivialStruct(); };
struct UserDefinedDestructor {
~UserDefinedDestructor();
int x;
NontrivialStruct nts;
};"#,
)?;
let rs_api = generate_rs_api(&ir)?;
assert_rs_matches!(
rs_api,
quote! {
impl Drop for UserDefinedDestructor {
#[inline(always)]
fn drop(&mut self) {
unsafe { crate::detail::__rust_thunk___ZN21UserDefinedDestructorD1Ev(self) }
}
}
}
);
assert_rs_matches!(rs_api, quote! {pub x: i32,});
assert_rs_matches!(rs_api, quote! {pub nts: std::mem::ManuallyDrop<NontrivialStruct>,});
Ok(())
}
/// nontrivial types without user-defined destructors should invoke
/// the C++ destructor to preserve the order of field destructions.
#[test]
fn test_impl_drop_nontrivial_member_destructor() -> Result<()> {
// TODO(jeanpierreda): This would be cleaner if the UserDefinedDestructor code were
// omitted. For example, we simulate it so that UserDefinedDestructor
// comes from another library.
let ir = ir_from_cc(
r#"struct UserDefinedDestructor final {
~UserDefinedDestructor();
};
struct TrivialStruct final { int i; };
struct NontrivialMembers final {
UserDefinedDestructor udd;
TrivialStruct ts;
int x;
};"#,
)?;
let rs_api = generate_rs_api(&ir)?;
assert_rs_matches!(
rs_api,
quote! {
impl Drop for NontrivialMembers {
#[inline(always)]
fn drop(&mut self) {
unsafe { crate::detail::__rust_thunk___ZN17NontrivialMembersD1Ev(self) }
}
}
}
);
assert_rs_matches!(rs_api, quote! {pub x: i32,});
assert_rs_matches!(rs_api, quote! {pub ts: TrivialStruct,});
assert_rs_matches!(
rs_api,
quote! {pub udd: std::mem::ManuallyDrop<UserDefinedDestructor>,}
);
Ok(())
}
/// Trivial types (at least those that are mapped to Copy rust types) do not
/// get a Drop impl.
#[test]
fn test_impl_drop_trivial() -> Result<()> {
let ir = ir_from_cc(
r#"struct Trivial final {
~Trivial() = default;
int x;
};"#,
)?;
let rs_api = generate_rs_api(&ir)?;
assert_rs_not_matches!(rs_api, quote! {impl Drop});
assert_rs_matches!(rs_api, quote! {pub x: i32});
let rs_api_impl = generate_rs_api_impl(&ir)?;
// TODO(b/213326125): Avoid generating thunk impls that are never called.
// (The test assertion below should be reversed once this bug is fixed.)
assert_cc_matches!(rs_api_impl, quote! { std::destroy_at });
Ok(())
}
#[test]
fn test_impl_default_explicitly_defaulted_constructor() -> Result<()> {
let ir = ir_from_cc(
r#"#pragma clang lifetime_elision
struct DefaultedConstructor final {
DefaultedConstructor() = default;
};"#,
)?;
let rs_api = generate_rs_api(&ir)?;
assert_rs_matches!(
rs_api,
quote! {
impl Default for DefaultedConstructor {
#[inline(always)]
fn default() -> Self {
let mut tmp = std::mem::MaybeUninit::<Self>::zeroed();
unsafe {
crate::detail::__rust_thunk___ZN20DefaultedConstructorC1Ev(&mut tmp);
tmp.assume_init()
}
}
}
}
);
let rs_api_impl = generate_rs_api_impl(&ir)?;
assert_cc_matches!(
rs_api_impl,
quote! {
extern "C" void __rust_thunk___ZN20DefaultedConstructorC1Ev(
class DefaultedConstructor* __this) {
rs_api_impl_support::construct_at (__this) ;
}
}
);
Ok(())
}
#[test]
fn test_impl_clone_that_propagates_lifetime() -> Result<()> {
// This test covers the case where a single lifetime applies to 1)
// the `__this` parameter and 2) other constructor parameters. For
// example, maybe the newly constructed object needs to have the
// same lifetime as the constructor's parameter. (This might require
// annotating the whole C++ struct with a lifetime, so maybe the
// example below is not fully realistic/accurate...).
let mut ir = ir_from_cc(
r#"#pragma clang lifetime_elision
struct Foo final {
[[clang::annotate("lifetimes", "a: a")]]
Foo(const int& i);
};"#,
)?;
let ctor: &mut Func = ir
.items_mut()
.filter_map(|item| match item {
Item::Func(func) => Some(func),
_ => None,
})
.find(|f| {
matches!(&f.name, UnqualifiedIdentifier::Constructor)
&& f.params.get(1).map(|p| p.identifier.identifier == "i").unwrap_or_default()
})
.unwrap();
{
// Double-check that the test scenario set up above uses the same lifetime
// for both of the constructor's parameters: `__this` and `i`.
assert_eq!(ctor.params.len(), 2);
let this_lifetime: LifetimeId =
*ctor.params[0].type_.rs_type.lifetime_args.first().unwrap();
let i_lifetime: LifetimeId =
*ctor.params[1].type_.rs_type.lifetime_args.first_mut().unwrap();
assert_eq!(i_lifetime, this_lifetime);
}
// Before cl/423346348 the generated Rust code would incorrectly look
// like this (note the mismatched 'a and 'b lifetimes):
// fn from<'b>(i: &'a i32) -> Self
// After this CL, this scenario will result in an explicit error.
let err = generate_rs_api(&ir).unwrap_err();
let msg = format!("{}", err);
assert!(
msg.contains("The lifetime of `__this` is unexpectedly also used by another parameter")
);
Ok(())
}
#[test]
fn test_impl_default_non_trivial_struct() -> Result<()> {
let ir = ir_from_cc(
r#"#pragma clang lifetime_elision
struct NonTrivialStructWithConstructors final {
NonTrivialStructWithConstructors();
~NonTrivialStructWithConstructors(); // Non-trivial
};"#,
)?;
let rs_api = generate_rs_api(&ir)?;
assert_rs_not_matches!(rs_api, quote! {impl Default});
Ok(())
}
#[test]
fn test_impl_from_for_explicit_conversion_constructor() -> Result<()> {
let ir = ir_from_cc(
r#"#pragma clang lifetime_elision
struct SomeStruct final {
explicit SomeStruct(int i);
};"#,
)?;
let rs_api = generate_rs_api(&ir)?;
// As discussed in b/214020567 for now we only generate `From::from` bindings
// for *implicit* C++ conversion constructors.
assert_rs_not_matches!(rs_api, quote! {impl From});
Ok(())
}
#[test]
fn test_impl_from_for_implicit_conversion_constructor() -> Result<()> {
let ir = ir_from_cc(
r#"#pragma clang lifetime_elision
struct SomeStruct final {
SomeStruct(int i); // implicit - no `explicit` keyword
};"#,
)?;
let rs_api = generate_rs_api(&ir)?;
// As discussed in b/214020567 we generate `From::from` bindings for
// *implicit* C++ conversion constructors.
assert_rs_matches!(
rs_api,
quote! {
impl From<i32> for SomeStruct {
#[inline(always)]
fn from(i: i32) -> Self {
let mut tmp = std::mem::MaybeUninit::<Self>::zeroed();
unsafe {
crate::detail::__rust_thunk___ZN10SomeStructC1Ei(&mut tmp, i);
tmp.assume_init()
}
}
}
}
);
Ok(())
}
#[test]
fn test_impl_from_for_implicit_conversion_from_reference() -> Result<()> {
let ir = ir_from_cc(
r#"#pragma clang lifetime_elision
struct SomeOtherStruct final { int i; };
struct StructUnderTest final {
StructUnderTest(const SomeOtherStruct& other); // implicit - no `explicit` keyword
};"#,
)?;
let rs_api = generate_rs_api(&ir)?;
// This is a regression test for b/223800038: We want to ensure that the
// code says `impl<'b>` (instead of incorrectly declaring that lifetime
// in `fn from<'b>`).
assert_rs_matches!(
rs_api,
quote! {
impl<'b> From<&'b SomeOtherStruct> for StructUnderTest {
#[inline(always)]
fn from(other: &'b SomeOtherStruct) -> Self {
let mut tmp = std::mem::MaybeUninit::<Self>::zeroed();
unsafe {
crate::detail::__rust_thunk___ZN15StructUnderTestC1ERK15SomeOtherStruct(
&mut tmp, other);
tmp.assume_init()
}
}
}
},
);
Ok(())
}
#[test]
fn test_impl_eq_for_member_function() -> Result<()> {
let ir = ir_from_cc(
r#"#pragma clang lifetime_elision
struct SomeStruct final {
inline bool operator==(const SomeStruct& other) const {
return i == other.i;
}
int i;
};"#,
)?;
let rs_api = generate_rs_api(&ir)?;
assert_rs_matches!(
rs_api,
quote! {
impl PartialEq<SomeStruct> for SomeStruct {
#[inline(always)]
fn eq<'a, 'b>(&'a self, other: &'b SomeStruct) -> bool {
unsafe { crate::detail::__rust_thunk___ZNK10SomeStructeqERKS_(self, other) }
}
}
}
);
let rs_api_impl = generate_rs_api_impl(&ir)?;
assert_cc_matches!(
rs_api_impl,
quote! {
extern "C" bool __rust_thunk___ZNK10SomeStructeqERKS_(
const class SomeStruct* __this, const class SomeStruct& other) {
return __this->operator==(other);
}
}
);
Ok(())
}
#[test]
fn test_impl_eq_for_free_function() -> Result<()> {
let ir = ir_from_cc(
r#"#pragma clang lifetime_elision
struct SomeStruct final { int i; };
bool operator==(const SomeStruct& lhs, const SomeStruct& rhs) {
return lhs.i == rhs.i;
}"#,
)?;
let rs_api = generate_rs_api(&ir)?;
assert_rs_matches!(
rs_api,
quote! {
impl PartialEq<SomeStruct> for SomeStruct {
#[inline(always)]
fn eq<'a, 'b>(&'a self, rhs: &'b SomeStruct) -> bool {
unsafe { crate::detail::__rust_thunk___ZeqRK10SomeStructS1_(self, rhs) }
}
}
}
);
Ok(())
}
#[test]
fn test_impl_eq_non_const_member_function() -> Result<()> {
let ir = ir_from_cc(
r#"#pragma clang lifetime_elision
struct SomeStruct final {
bool operator==(const SomeStruct& other) /* no `const` here */;
};"#,
)?;
let rs_api = generate_rs_api(&ir)?;
assert_rs_not_matches!(rs_api, quote! {impl PartialEq});
Ok(())
}
#[test]
fn test_impl_eq_rhs_by_value() -> Result<()> {
let ir = ir_from_cc(
r#"#pragma clang lifetime_elision
struct SomeStruct final {
bool operator==(SomeStruct other) const;
};"#,
)?;
let rs_api = generate_rs_api(&ir)?;
assert_rs_not_matches!(rs_api, quote! {impl PartialEq});
Ok(())
}
#[test]
fn test_thunk_ident_function() {
let func = ir_func("foo");
assert_eq!(thunk_ident(&func), make_rs_ident("__rust_thunk___Z3foov"));
}
#[test]
fn test_thunk_ident_special_names() {
let ir = ir_from_cc("struct Class {};").unwrap();
let destructor =
ir.functions().find(|f| f.name == UnqualifiedIdentifier::Destructor).unwrap();
assert_eq!(thunk_ident(destructor), make_rs_ident("__rust_thunk___ZN5ClassD1Ev"));
let default_constructor = ir
.functions()
.find(|f| f.name == UnqualifiedIdentifier::Constructor && f.params.len() == 1)
.unwrap();
assert_eq!(thunk_ident(default_constructor), make_rs_ident("__rust_thunk___ZN5ClassC1Ev"));
}
#[test]
fn test_elided_lifetimes() -> Result<()> {
let ir = ir_from_cc(
r#"#pragma clang lifetime_elision
struct S final {
int& f(int& i);
};"#,
)?;
let rs_api = generate_rs_api(&ir)?;
assert_rs_matches!(
rs_api,
quote! {
pub fn f<'a, 'b>(&'a mut self, i: &'b mut i32) -> &'a mut i32 { ... }
}
);
assert_rs_matches!(
rs_api,
quote! {
pub(crate) fn __rust_thunk___ZN1S1fERi<'a, 'b>(__this: &'a mut S, i: &'b mut i32)
-> &'a mut i32;
}
);
Ok(())
}
#[test]
fn test_annotated_lifetimes() -> Result<()> {
let ir = ir_from_cc(
r#"[[clang::annotate("lifetimes", "a, a -> a")]]
int& f(int& i1, int& i2);
"#,
)?;
let rs_api = generate_rs_api(&ir)?;
assert_rs_matches!(
rs_api,
quote! {
pub fn f<'a>(i1: &'a mut i32, i2: &'a mut i32) -> &'a mut i32 { ... }
}
);
assert_rs_matches!(
rs_api,
quote! {
pub(crate) fn __rust_thunk___Z1fRiS_<'a>(i1: &'a mut i32, i2: &'a mut i32)
-> &'a mut i32;
}
);
Ok(())
}
#[test]
fn test_format_generic_params() -> Result<()> {
assert_rs_matches!(format_generic_params(std::iter::empty::<syn::Ident>()), quote! {});
let idents = ["T1", "T2"].iter().map(|s| make_rs_ident(s));
assert_rs_matches!(format_generic_params(idents), quote! { < T1, T2 > });
let lifetimes = ["a", "b"]
.iter()
.map(|s| syn::Lifetime::new(&format!("'{}", s), proc_macro2::Span::call_site()));
assert_rs_matches!(format_generic_params(lifetimes), quote! { < 'a, 'b > });
Ok(())
}
#[test]
fn test_overloaded_functions() -> Result<()> {
// TODO(b/213280424): We don't support creating bindings for overloaded
// functions yet, except in the case of overloaded constructors with a
// single parameter.
let ir = ir_from_cc(
r#" #pragma clang lifetime_elision
void f();
void f(int i);
struct S1 final {
void f();
void f(int i);
};
struct S2 final {
void f();
};
struct S3 final {
S3(int i);
S3(double d);
};
"#,
)?;
let rs_api = generate_rs_api(&ir)?;
let rs_api_str = tokens_to_string(rs_api.clone())?;
// Cannot overload free functions.
assert!(rs_api_str.contains("Error while generating bindings for item 'f'"));
assert_rs_not_matches!(rs_api, quote! {pub fn f()});
assert_rs_not_matches!(rs_api, quote! {pub fn f(i: i32)});
// Cannot overload member functions.
assert!(rs_api_str.contains("Error while generating bindings for item 'S1::f'"));
assert_rs_not_matches!(rs_api, quote! {pub fn f(... S1 ...)});
// But we can import member functions that have the same name as a free
// function.
assert_rs_matches!(rs_api, quote! {pub fn f<'a>(&'a mut self)});
// We can also import overloaded single-parameter constructors.
assert_rs_matches!(rs_api, quote! {impl From<i32> for S3});
assert_rs_matches!(rs_api, quote! {impl From<f64> for S3});
Ok(())
}
#[test]
fn test_type_alias() -> Result<()> {
let ir = ir_from_cc(
r#"
// MyTypedefDecl doc comment
typedef int MyTypedefDecl;
using MyTypeAliasDecl = int;
using MyTypeAliasDecl_Alias = MyTypeAliasDecl;
struct S final {};
using S_Alias = S;
using S_Alias_Alias = S_Alias;
inline void f(MyTypedefDecl t) {}
"#,
)?;
let rs_api = generate_rs_api(&ir)?;
assert_rs_matches!(
rs_api,
quote! {
#[doc = " MyTypedefDecl doc comment"]
pub type MyTypedefDecl = i32;
}
);
assert_rs_matches!(rs_api, quote! { pub type MyTypeAliasDecl = i32; });
assert_rs_matches!(rs_api, quote! { pub type MyTypeAliasDecl_Alias = MyTypeAliasDecl; });
assert_rs_matches!(rs_api, quote! { pub type S_Alias = S; });
assert_rs_matches!(rs_api, quote! { pub type S_Alias_Alias = S_Alias; });
assert_rs_matches!(rs_api, quote! { pub fn f(t: MyTypedefDecl) });
assert_cc_matches!(
generate_rs_api_impl(&ir)?,
quote! {
extern "C" void __rust_thunk___Z1fi(MyTypedefDecl t){ f (t) ; }
}
);
Ok(())
}
#[test]
fn test_rs_type_kind_implements_copy() -> Result<()> {
let template = r#" LIFETIMES
struct [[clang::trivial_abi]] TrivialStruct final { int i; };
struct [[clang::trivial_abi]] UserDefinedCopyConstructor final {
UserDefinedCopyConstructor(const UserDefinedCopyConstructor&);
};
using IntAlias = int;
using TrivialAlias = TrivialStruct;
using NonTrivialAlias = UserDefinedCopyConstructor;
void func(PARAM_TYPE some_param);
"#;
assert_impl_all!(i32: Copy);
assert_impl_all!(&i32: Copy);
assert_not_impl_all!(&mut i32: Copy);
assert_impl_all!(Option<&i32>: Copy);
assert_not_impl_all!(Option<&mut i32>: Copy);
assert_impl_all!(*const i32: Copy);
assert_impl_all!(*mut i32: Copy);
struct Test {
// Test inputs:
cc: &'static str,
lifetimes: bool,
// Expected test outputs:
rs: &'static str,
is_copy: bool,
}
let tests = vec![
// Validity of the next few tests is verified via
// `assert_[not_]impl_all!` static assertions above.
Test { cc: "int", lifetimes: true, rs: "i32", is_copy: true },
Test { cc: "const int&", lifetimes: true, rs: "&'a i32", is_copy: true },
Test { cc: "int&", lifetimes: true, rs: "&'a mut i32", is_copy: false },
Test { cc: "const int*", lifetimes: true, rs: "Option<&'a i32>", is_copy: true },
Test { cc: "int*", lifetimes: true, rs: "Option<&'a mut i32>", is_copy: false },
Test { cc: "const int*", lifetimes: false, rs: "*const i32", is_copy: true },
Test { cc: "int*", lifetimes: false, rs: "*mut i32", is_copy: true },
// Tests below have been thought-through and verified "manually".
// TrivialStruct is expected to derive Copy.
Test { cc: "TrivialStruct", lifetimes: true, rs: "TrivialStruct", is_copy: true },
Test {
cc: "UserDefinedCopyConstructor",
lifetimes: true,
rs: "UserDefinedCopyConstructor",
is_copy: false,
},
Test { cc: "IntAlias", lifetimes: true, rs: "IntAlias", is_copy: true },
Test { cc: "TrivialAlias", lifetimes: true, rs: "TrivialAlias", is_copy: true },
Test { cc: "NonTrivialAlias", lifetimes: true, rs: "NonTrivialAlias", is_copy: false },
];
for test in tests.iter() {
let test_name = format!("cc='{}', lifetimes={}", test.cc, test.lifetimes);
let cc_input = template.replace("PARAM_TYPE", test.cc).replace(
"LIFETIMES",
if test.lifetimes { "#pragma clang lifetime_elision" } else { "" },
);
let ir = ir_from_cc(&cc_input)?;
let f = retrieve_func(&ir, "func");
let t = RsTypeKind::new(&f.params[0].type_.rs_type, &ir)?;
let lifetime_to_name: HashMap<LifetimeId, String> =
t.lifetimes().map(|lifetime_id| (lifetime_id, "a".to_string())).collect();
let fmt = tokens_to_string(t.format(&ir, &lifetime_to_name)?)?;
assert_eq!(test.rs, fmt, "Testing: {}", test_name);
assert_eq!(test.is_copy, t.implements_copy(), "Testing: {}", test_name);
}
Ok(())
}
#[test]
fn test_rs_type_kind_is_shared_ref_to_with_lifetimes() -> Result<()> {
let ir = ir_from_cc(
"#pragma clang lifetime_elision
struct SomeStruct {};
void foo(const SomeStruct& foo_param);
void bar(SomeStruct& bar_param);",
)?;
let record = ir.records().next().unwrap();
let foo_func = retrieve_func(&ir, "foo");
let bar_func = retrieve_func(&ir, "bar");
// const-ref + lifetimes in C++ ===> shared-ref in Rust
assert_eq!(foo_func.params.len(), 1);
let foo_param = &foo_func.params[0];
assert_eq!(&foo_param.identifier.identifier, "foo_param");
let foo_type = RsTypeKind::new(&foo_param.type_.rs_type, &ir)?;
assert!(foo_type.is_shared_ref_to(record));
assert!(matches!(foo_type, RsTypeKind::Reference { mutability: Mutability::Const, .. }));
// non-const-ref + lifetimes in C++ ===> mutable-ref in Rust
assert_eq!(bar_func.params.len(), 1);
let bar_param = &bar_func.params[0];
assert_eq!(&bar_param.identifier.identifier, "bar_param");
let bar_type = RsTypeKind::new(&bar_param.type_.rs_type, &ir)?;
assert!(!bar_type.is_shared_ref_to(record));
assert!(matches!(bar_type, RsTypeKind::Reference { mutability: Mutability::Mut, .. }));
Ok(())
}
#[test]
fn test_rs_type_kind_is_shared_ref_to_without_lifetimes() -> Result<()> {
let ir = ir_from_cc(
"struct SomeStruct {};
void foo(const SomeStruct& foo_param);",
)?;
let record = ir.records().next().unwrap();
let foo_func = retrieve_func(&ir, "foo");
// const-ref + *no* lifetimes in C++ ===> const-pointer in Rust
assert_eq!(foo_func.params.len(), 1);
let foo_param = &foo_func.params[0];
assert_eq!(&foo_param.identifier.identifier, "foo_param");
let foo_type = RsTypeKind::new(&foo_param.type_.rs_type, &ir)?;
assert!(!foo_type.is_shared_ref_to(record));
assert!(matches!(foo_type, RsTypeKind::Pointer { mutability: Mutability::Const, .. }));
Ok(())
}
#[test]
fn test_rs_type_kind_dfs_iter_ordering() {
// Set up a test input representing: A<B<C>, D<E>>.
let a = {
let b = {
let c = RsTypeKind::Other { name: "C", type_args: vec![] };
RsTypeKind::Other { name: "B", type_args: vec![c] }
};
let d = {
let e = RsTypeKind::Other { name: "E", type_args: vec![] };
RsTypeKind::Other { name: "D", type_args: vec![e] }
};
RsTypeKind::Other { name: "A", type_args: vec![b, d] }
};
let dfs_names = a
.dfs_iter()
.map(|t| match t {
RsTypeKind::Other { name, .. } => *name,
_ => unreachable!("Only 'other' types are used in this test"),
})
.collect_vec();
assert_eq!(vec!["A", "B", "C", "D", "E"], dfs_names);
}
#[test]
fn test_rs_type_kind_dfs_iter_ordering_for_func_ptr() {
// Set up a test input representing: fn(A, B) -> C
let f = {
let a = RsTypeKind::Other { name: "A", type_args: vec![] };
let b = RsTypeKind::Other { name: "B", type_args: vec![] };
let c = RsTypeKind::Other { name: "C", type_args: vec![] };
RsTypeKind::FuncPtr { abi: "blah", param_types: vec![a, b], return_type: Box::new(c) }
};
let dfs_names = f
.dfs_iter()
.map(|t| match t {
RsTypeKind::FuncPtr { .. } => "fn",
RsTypeKind::Other { name, .. } => *name,
_ => unreachable!("Only FuncPtr and Other kinds are used in this test"),
})
.collect_vec();
assert_eq!(vec!["fn", "A", "B", "C"], dfs_names);
}
#[test]
fn test_rs_type_kind_lifetimes() -> Result<()> {
let ir = ir_from_cc(
r#"
#pragma clang lifetime_elision
using TypeAlias = int&;
struct SomeStruct {};
void foo(int a, int& b, int* c, int** d, TypeAlias e, SomeStruct f); "#,
)?;
let f = retrieve_func(&ir, "foo");
let ret = RsTypeKind::new(&f.return_type.rs_type, &ir)?;
let a = RsTypeKind::new(&f.params[0].type_.rs_type, &ir)?;
let b = RsTypeKind::new(&f.params[1].type_.rs_type, &ir)?;
let c = RsTypeKind::new(&f.params[2].type_.rs_type, &ir)?;
let d = RsTypeKind::new(&f.params[3].type_.rs_type, &ir)?;
let e = RsTypeKind::new(&f.params[4].type_.rs_type, &ir)?;
let f = RsTypeKind::new(&f.params[5].type_.rs_type, &ir)?;
assert_eq!(0, ret.lifetimes().count()); // No lifetimes on `void`.
assert_eq!(0, a.lifetimes().count()); // No lifetimes on `int`.
assert_eq!(1, b.lifetimes().count()); // `&'a i32` has a single lifetime.
assert_eq!(1, c.lifetimes().count()); // `Option<&'b i32>` has a single lifetime.
assert_eq!(2, d.lifetimes().count()); // `&'c Option<&'d i32>` has two lifetimes.
assert_eq!(1, e.lifetimes().count()); // Lifetime of underlying type should show through.
assert_eq!(0, f.lifetimes().count()); // No lifetimes on structs (yet).
Ok(())
}
#[test]
fn test_rs_type_kind_lifetimes_raw_ptr() -> Result<()> {
let ir = ir_from_cc("void foo(int* a);")?;
let f = retrieve_func(&ir, "foo");
let a = RsTypeKind::new(&f.params[0].type_.rs_type, &ir)?;
assert_eq!(0, a.lifetimes().count()); // No lifetimes on `int*`.
Ok(())
}
#[test]
fn test_rust_keywords_are_escaped_in_rs_api_file() -> Result<()> {
let ir = ir_from_cc("struct type { int dyn; };")?;
let rs_api = generate_rs_api(&ir)?;
assert_rs_matches!(rs_api, quote! { struct r#type { ... r#dyn: i32 ... } });
Ok(())
}
#[test]
fn test_rust_keywords_are_not_escaped_in_rs_api_impl_file() -> Result<()> {
let ir = ir_from_cc("struct type { int dyn; };")?;
let rs_api_impl = generate_rs_api_impl(&ir)?;
assert_cc_matches!(rs_api_impl, quote! { static_assert(offsetof(class type, dyn) ... ) });
Ok(())
}
#[test]
fn test_no_aligned_attr() {
let ir = ir_from_cc("struct SomeStruct {};").unwrap();
let rs_api = generate_rs_api(&ir).unwrap();
assert_rs_matches! {rs_api, quote! {
#[repr(C)]
pub struct SomeStruct { ... }
}};
}
#[test]
fn test_aligned_attr() {
let ir = ir_from_cc("struct SomeStruct {} __attribute__((aligned(64)));").unwrap();
let rs_api = generate_rs_api(&ir).unwrap();
assert_rs_matches! {rs_api, quote! {
#[repr(C, align(64))]
pub struct SomeStruct { ... }
}
};
}
/// !Unpin references should not be pinned.
#[test]
fn test_nonunpin_ref_param() -> Result<()> {
let rs_api_impl = generate_rs_api(&ir_from_cc(
r#"
#pragma clang lifetime_elision
struct S {~S();};
void Function(const S& s);
"#,
)?)?;
assert_rs_matches!(
rs_api_impl,
quote! {
fn Function<'a>(s: &'a S) { ... }
}
);
Ok(())
}
/// !Unpin mut references must be pinned.
#[test]
fn test_nonunpin_mut_param() -> Result<()> {
let rs_api_impl = generate_rs_api(&ir_from_cc(
r#"
#pragma clang lifetime_elision
struct S {~S();};
void Function(S& s);
"#,
)?)?;
assert_rs_matches!(
rs_api_impl,
quote! {
fn Function<'a>(s: std::pin::Pin<&'a mut S>) { ... }
}
);
Ok(())
}
/// !Unpin &self should not be pinned.
#[test]
fn test_nonunpin_ref_self() -> Result<()> {
let rs_api_impl = generate_rs_api(&ir_from_cc(
r#"
#pragma clang lifetime_elision
struct S {
~S();
void Function() const;
};
"#,
)?)?;
assert_rs_matches!(
rs_api_impl,
quote! {
fn Function<'a>(&'a self) { ... }
}
);
Ok(())
}
/// !Unpin &mut self must be pinned.
#[test]
fn test_nonunpin_mut_self() -> Result<()> {
let rs_api_impl = generate_rs_api(&ir_from_cc(
r#"
#pragma clang lifetime_elision
struct S {
~S();
void Function();
};
"#,
)?)?;
assert_rs_matches!(
rs_api_impl,
quote! {
fn Function<'a>(self: std::pin::Pin<&'a mut Self>) { ... }
}
);
Ok(())
}
/// Drop::drop must not use self : Pin<...>.
#[test]
fn test_nonunpin_drop() -> Result<()> {
let rs_api_impl = generate_rs_api(&ir_from_cc(
r#"
struct S {~S();};
"#,
)?)?;
assert_rs_matches!(
rs_api_impl,
quote! {
fn drop(&mut self) { ... }
}
);
Ok(())
}
#[test]
fn test_nonunpin_one_arg_constructor() -> Result<()> {
let ir = ir_from_cc(
r#"#pragma clang lifetime_elision
// This type must be `!Unpin`.
struct HasConstructor {explicit HasConstructor(unsigned char input) {}};"#,
)?;
let rs_api = generate_rs_api(&ir)?;
assert_rs_matches!(rs_api, quote! {impl !Unpin for HasConstructor {} });
assert_rs_matches!(
rs_api,
quote! {
impl ctor::CtorNew<u8> for HasConstructor {
type CtorType = impl ctor::Ctor<Output = Self>;
#[inline (always)]
fn ctor_new(input: u8) -> Self::CtorType {
ctor::FnCtor::new(move |dest: std::pin::Pin<&mut std::mem::MaybeUninit<Self>>| {
unsafe {
crate::detail::__rust_thunk___ZN14HasConstructorC1Eh(std::pin::Pin::into_inner_unchecked(dest), input);
}
})
}
}
}
);
Ok(())
}
}