| // 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, Context, Result}; |
| use code_gen_utils::format_cc_ident; |
| use itertools::Itertools; |
| use proc_macro2::TokenStream; |
| use quote::quote; |
| use rustc_hir::{Item, ItemKind, Node, Unsafety}; |
| use rustc_interface::Queries; |
| use rustc_middle::dep_graph::DepContext; |
| use rustc_middle::middle::exported_symbols::ExportedSymbol; |
| use rustc_middle::ty::{self, Ty, TyCtxt}; // See <internal link>/ty.html#import-conventions |
| use rustc_span::def_id::{DefId, LocalDefId, LOCAL_CRATE}; |
| use rustc_target::spec::abi::Abi; |
| use rustc_target::spec::PanicStrategy; |
| |
| pub struct GeneratedBindings { |
| pub h_body: TokenStream, |
| } |
| |
| impl GeneratedBindings { |
| pub fn generate(tcx: TyCtxt) -> Result<Self> { |
| match tcx.sess().panic_strategy() { |
| PanicStrategy::Unwind => bail!("No support for panic=unwind strategy (b/254049425)"), |
| PanicStrategy::Abort => (), |
| }; |
| |
| let top_comment = { |
| let crate_name = tcx.crate_name(LOCAL_CRATE); |
| let txt = format!( |
| "Automatically @generated C++ bindings for the following Rust crate:\n\ |
| {crate_name}" |
| ); |
| quote! { __COMMENT__ #txt __NEWLINE__ } |
| }; |
| |
| let h_body = { |
| let crate_content = format_crate(tcx).unwrap_or_else(|err| { |
| let txt = format!("Failed to generate bindings for the crate: {}", err); |
| quote! { __COMMENT__ #txt } |
| }); |
| // TODO(b/251445877): Replace `#pragma once` with include guards. |
| quote! { |
| #top_comment |
| __HASH_TOKEN__ pragma once __NEWLINE__ |
| __NEWLINE__ |
| #crate_content |
| } |
| }; |
| |
| Ok(Self { h_body }) |
| } |
| } |
| |
| /// Helper (used by `bindings_driver` and `test::run_compiler`) for invoking |
| /// functions operating on `TyCtxt`. |
| pub fn enter_tcx<'tcx, F, T>( |
| queries: &'tcx Queries<'tcx>, |
| f: F, |
| ) -> rustc_interface::interface::Result<T> |
| where |
| F: FnOnce(TyCtxt<'tcx>) -> T + Send, |
| T: Send, |
| { |
| let query_context = queries.global_ctxt()?; |
| Ok(query_context.peek_mut().enter(f)) |
| } |
| |
| fn format_ret_ty(ty: Ty) -> Result<TokenStream> { |
| match ty.kind() { |
| ty::TyKind::Never => Ok(quote! { void }), // `!` |
| ty::TyKind::Tuple(types) if types.len() == 0 => Ok(quote! { void }), // `()` |
| _ => format_ty(ty), |
| } |
| } |
| |
| fn format_ty(ty: Ty) -> Result<TokenStream> { |
| Ok(match ty.kind() { |
| ty::TyKind::Never => { |
| // TODO(b/254507801): Maybe translate into `crubit::Never`? |
| bail!("The never type `!` is only supported as a return type (b/254507801)"); |
| }, |
| ty::TyKind::Tuple(types) => { |
| if types.len() == 0 { |
| // TODO(b/254507801): Maybe translate into `crubit::Unit`? |
| bail!("The unit type `()` / `void` is only supported as a return type"); |
| } else { |
| // TODO(b/254099023): Add support for tuples. |
| bail!("Tuples are not supported yet: {} (b/254099023)", ty); |
| } |
| } |
| ty::TyKind::Bool => quote! { bool }, |
| ty::TyKind::Float(ty::FloatTy::F32) => quote! { float }, |
| ty::TyKind::Float(ty::FloatTy::F64) => quote! { double }, |
| |
| ty::TyKind::Char |
| | ty::TyKind::Int( |
| ty::IntTy::Isize | ty::IntTy::I8 | ty::IntTy::I16 | ty::IntTy::I32 | ty::IntTy::I64, |
| ) |
| | ty::TyKind::Uint( |
| ty::UintTy::Usize |
| | ty::UintTy::U8 |
| | ty::UintTy::U16 |
| | ty::UintTy::U32 |
| | ty::UintTy::U64, |
| ) => { |
| // TODO(b/254094545): Add support for returning TokenStream *and* include paths. |
| bail!("No support yet for `#include`ing C++ equivalent of `{ty}` (b/254094545)") |
| } |
| |
| ty::TyKind::Int(ty::IntTy::I128) | ty::TyKind::Uint(ty::UintTy::U128) => { |
| // TODO(b/254094650): Consider mapping this to Clang's (and GCC's) `__int128` |
| // or to `absl::in128`. |
| bail!("C++ doesn't have a standard equivalent of `{ty}` (b/254094650)"); |
| } |
| |
| ty::TyKind::Adt(..) |
| | ty::TyKind::Foreign(..) |
| | ty::TyKind::Str |
| | ty::TyKind::Array(..) |
| | ty::TyKind::Slice(..) |
| | ty::TyKind::RawPtr(..) |
| | ty::TyKind::Ref(..) |
| | ty::TyKind::FnPtr(..) |
| | ty::TyKind::Dynamic(..) |
| | ty::TyKind::Generator(..) |
| | ty::TyKind::GeneratorWitness(..) |
| | ty::TyKind::Projection(..) |
| | ty::TyKind::Opaque(..) |
| | ty::TyKind::Param(..) |
| | ty::TyKind::Bound(..) |
| | ty::TyKind::Placeholder(..) => { |
| bail!("The following Rust type is not supported yet: {ty}") |
| } |
| ty::TyKind::Closure(..) |
| | ty::TyKind::FnDef(..) |
| | ty::TyKind::Infer(..) |
| | ty::TyKind::Error(..) => { |
| // `Closure` types are assumed to never appear in a public API of a crate (only |
| // function-body-local variables/values should be able to have a closure type). |
| // |
| // `FnDef` is assumed to never appear in a public API of a crate - this seems to |
| // be an internal, compiler-only type similar to `Closure` (e.g. |
| // based on the statement from https://doc.rust-lang.org/stable/nightly-rustc/rustc_middle/ty/enum.TyKind.html#variant.FnDef |
| // that "each function has a unique type" |
| // |
| // `Infer` and `Error` types should be impossible at the time when Crubit's code |
| // runs (after the "analysis" phase of the Rust compiler). |
| panic!("Unexpected TyKind: {:?}", ty.kind()); |
| } |
| }) |
| } |
| |
| /// Formats a function with the given `def_id`. |
| /// |
| /// Will panic if `def_id` |
| /// - is invalid |
| /// - doesn't identify a function, |
| /// - has generic parameters (any kind - lifetime parameters, type parameters, |
| /// or const parameters). |
| fn format_fn(tcx: TyCtxt, def_id: LocalDefId) -> Result<TokenStream> { |
| let def_id: DefId = def_id.to_def_id(); // Convert LocalDefId to DefId. |
| |
| let item_name = tcx.item_name(def_id); |
| let symbol_name = { |
| // Call to `mono` is ok - doc comment requires no generic parameters (although |
| // lifetime parameters would have been okay). |
| let instance = ty::Instance::mono(tcx, def_id); |
| tcx.symbol_name(instance) |
| }; |
| |
| let sig = tcx |
| .fn_sig(def_id) |
| .no_bound_vars() |
| .expect("Doc comment points out there should be no generic parameters"); |
| |
| if sig.c_variadic { |
| // TODO(b/254097223): Add support for variadic functions. |
| bail!("C variadic functions are not supported (b/254097223)"); |
| } |
| |
| match sig.unsafety { |
| Unsafety::Normal => (), |
| Unsafety::Unsafe => { |
| // TODO(b/254095482): Figure out how to handle `unsafe` functions. |
| bail!("Bindings for `unsafe` functions are not fully designed yet (b/254095482)"); |
| } |
| } |
| |
| match sig.abi { |
| // "C" ABI is okay: Before https://rust-lang.github.io/rfcs/2945-c-unwind-abi.html a Rust |
| // panic that "escapes" a "C" ABI function leads to Undefined Behavior. This is |
| // unfortunate, but Crubit's `panics_and_exceptions.md` documents that `-Cpanic=abort` is |
| // the only supported configuration. |
| // |
| // After https://rust-lang.github.io/rfcs/2945-c-unwind-abi.html a Rust panic that |
| // tries to "escape" a "C" ABI function will terminate the program. This is okay. |
| Abi::C { unwind: false } => (), |
| |
| // "C-unwind" ABI is okay: After https://rust-lang.github.io/rfcs/2945-c-unwind-abi.html a |
| // new "C-unwind" ABI may be used by Rust functions that want to safely propagate Rust |
| // panics through frames that may belong to another language. |
| Abi::C { unwind: true } => (), |
| |
| // TODO(b/254097223): Add support for Rust thunks. |
| _ => bail!("Non-C ABI is not supported yet (b/254097223)"), |
| }; |
| if item_name.as_str() != symbol_name.name { |
| bail!("Mangled or renamed symbols are not supported yet"); |
| } |
| |
| let ret_type = format_ret_ty(sig.output()).context("Error formatting function return type")?; |
| let fn_name = format_cc_ident(item_name.as_str()).context("Error formatting function name")?; |
| let arg_names = tcx |
| .fn_arg_names(def_id) |
| .iter() |
| .enumerate() |
| .map(|(index, ident)| { |
| format_cc_ident(ident.as_str()) |
| .unwrap_or_else(|_err| format_cc_ident(&format!("__param_{index}")).unwrap()) |
| }) |
| .collect_vec(); |
| let arg_types = sig |
| .inputs() |
| .iter() |
| .enumerate() |
| .map(|(index, ty)| { |
| format_ty(*ty) |
| .with_context(|| format!("Error formatting the type of parameter #{index}")) |
| }) |
| .collect::<Result<Vec<_>>>()?; |
| Ok(quote! { |
| extern "C" #ret_type #fn_name ( |
| #( #arg_types #arg_names ),* |
| ); |
| }) |
| } |
| |
| /// Formats a Rust item idenfied by `def_id`. |
| /// |
| /// Will panic if `def_id` is invalid (i.e. doesn't identify a Rust node or |
| /// item). |
| fn format_def(tcx: TyCtxt, def_id: LocalDefId) -> Result<TokenStream> { |
| match tcx.hir().get_by_def_id(def_id) { |
| Node::Item(item) => match item { |
| Item { kind: ItemKind::Fn(_hir_fn_sig, generics, _body), .. } => { |
| if generics.params.len() == 0 { |
| format_fn(tcx, def_id) |
| } else { |
| bail!( |
| "Generic functions (lifetime-generic or type-generic) are not supported yet" |
| ) |
| } |
| } |
| Item { kind, .. } => bail!("Unsupported rustc_hir::hir::ItemKind: {}", kind.descr()), |
| }, |
| _unsupported_node => bail!("Unsupported rustc_hir::hir::Node"), |
| } |
| } |
| |
| /// Formats a C++ comment explaining why no bindings have been generated for |
| /// `local_def_id`. |
| fn format_unsupported_def( |
| tcx: TyCtxt, |
| local_def_id: LocalDefId, |
| err: anyhow::Error, |
| ) -> TokenStream { |
| let span = tcx.sess().source_map().span_to_embeddable_string(tcx.def_span(local_def_id)); |
| let name = tcx.def_path_str(local_def_id.to_def_id()); |
| |
| // https://docs.rs/anyhow/latest/anyhow/struct.Error.html#display-representations |
| // says: To print causes as well [...], use the alternate selector “{:#}”. |
| let msg = format!("Error generating bindings for `{name}` defined at {span}: {err:#}"); |
| quote! { __NEWLINE__ __NEWLINE__ __COMMENT__ #msg __NEWLINE__ } |
| } |
| |
| /// Formats all public items from the Rust crate being compiled (aka the |
| /// `LOCAL_CRATE`). |
| fn format_crate(tcx: TyCtxt) -> Result<TokenStream> { |
| // TODO(lukasza): We probably shouldn't be using `exported_symbols` as the main |
| // entry point for finding Rust definitions that need to be wrapping in C++ |
| // bindings. For example, it _seems_ that things like `type` aliases or |
| // `struct`s (without an `impl`) won't be visible to a linker and therefore |
| // won't have exported symbols. Additionally, walking Rust's modules top-down |
| // might result in easier translation into C++ namespaces. |
| let snippets = |
| tcx.exported_symbols(LOCAL_CRATE).iter().filter_map(move |(symbol, _)| match symbol { |
| ExportedSymbol::NonGeneric(def_id) => { |
| // It seems that non-generic exported symbols should all be defined in the |
| // `LOCAL_CRATE`. Furthermore, `def_id` seems to be a `LocalDefId`. OTOH, it |
| // isn't clear why `ExportedSymbol::NonGeneric` holds a `DefId` rather than a |
| // `LocalDefId`. For now, we assert `expect_local` below (and if it fails, then |
| // hopefully it will help us understand these things better and maybe add |
| // extra unit tests against out code). |
| let local_id = def_id.expect_local(); |
| |
| Some(match format_def(tcx, local_id) { |
| Ok(snippet) => snippet, |
| Err(err) => format_unsupported_def(tcx, local_id, err), |
| }) |
| } |
| ExportedSymbol::Generic(def_id, _substs) => { |
| // Ignore non-local defs. Map local defs to an unsupported comment. |
| // |
| // We are guessing that a non-local `def_id` can happen when the `LOCAL_CRATE` |
| // exports a monomorphization/specialization of a generic defined in a different |
| // crate. One specific example (covered via `async fn` in one of the tests) is |
| // `DefId(2:14250 ~ core[ef75]::future::from_generator)`. |
| def_id.as_local().map(|local_id| { |
| format_unsupported_def(tcx, local_id, anyhow!("Generics are not supported yet.")) |
| }) |
| } |
| ExportedSymbol::DropGlue(..) | ExportedSymbol::NoDefId(..) => None, |
| }); |
| |
| // TODO(b/254690602): Decide whether using `#crate_name` as the name of the |
| // top-level namespace is okay (e.g. investigate if this name is globally |
| // unique + ergonomic). |
| let crate_name = format_cc_ident(tcx.crate_name(LOCAL_CRATE).as_str())?; |
| Ok(quote! { |
| namespace #crate_name { |
| #( #snippets )* |
| } |
| }) |
| } |
| |
| #[cfg(test)] |
| pub mod tests { |
| use super::{format_def, format_ret_ty, format_ty, GeneratedBindings}; |
| |
| use anyhow::Result; |
| use itertools::Itertools; |
| use proc_macro2::TokenStream; |
| use quote::quote; |
| use rustc_middle::ty::{Ty, TyCtxt}; |
| use rustc_span::def_id::LocalDefId; |
| use std::path::PathBuf; |
| |
| use token_stream_matchers::{assert_cc_matches, assert_cc_not_matches}; |
| |
| pub fn get_sysroot_for_testing() -> PathBuf { |
| let runfiles = runfiles::Runfiles::create().unwrap(); |
| runfiles.rlocation(if std::env::var("LEGACY_TOOLCHAIN_RUST_TEST").is_ok() { |
| "google3/third_party/unsupported_toolchains/rust/toolchains/nightly" |
| } else { |
| "google3/nowhere/llvm/rust" |
| }) |
| } |
| |
| #[test] |
| #[should_panic(expected = "Test inputs shouldn't cause compilation errors")] |
| fn test_infra_panic_when_test_input_contains_syntax_errors() { |
| run_compiler("syntax error here", |_tcx| panic!("This part shouldn't execute")) |
| } |
| |
| #[test] |
| #[should_panic(expected = "Test inputs shouldn't cause compilation errors")] |
| fn test_infra_panic_when_test_input_triggers_analysis_errors() { |
| run_compiler("#![feature(no_such_feature)]", |_tcx| panic!("This part shouldn't execute")) |
| } |
| |
| #[test] |
| #[should_panic(expected = "Test inputs shouldn't cause compilation errors")] |
| fn test_infra_panic_when_test_input_triggers_warnings() { |
| run_compiler("pub fn foo(unused_parameter: i32) {}", |_tcx| { |
| panic!("This part shouldn't execute") |
| }) |
| } |
| |
| #[test] |
| fn test_infra_nightly_features_ok_in_test_input() { |
| // This test arbitrarily picks `yeet_expr` as an example of a feature that |
| // hasn't yet been stabilized. |
| let test_src = r#" |
| // This test is supposed to test that *nightly* features are ok |
| // in the test input. The `forbid` directive below helps to |
| // ensure that we'll realize in the future when the `yeet_expr` |
| // feature gets stabilized, making it not quite fitting for use |
| // in this test. |
| #![forbid(stable_features)] |
| |
| #![feature(yeet_expr)] |
| "#; |
| run_compiler(test_src, |_tcx| ()) |
| } |
| |
| #[test] |
| fn test_infra_stabilized_features_ok_in_test_input() { |
| // This test arbitrarily picks `const_ptr_offset_from` as an example of a |
| // feature that has been already stabilized. |
| run_compiler("#![feature(const_ptr_offset_from)]", |_tcx| ()) |
| } |
| |
| #[test] |
| #[should_panic(expected = "No items named `missing_name`.\n\ |
| Instead found:\n`bar`,\n`foo`,\n`m1`,\n`m2`,\n`std`")] |
| fn test_find_def_id_by_name_panic_when_no_item_with_matching_name() { |
| let test_src = r#" |
| pub extern "C" fn foo() {} |
| |
| pub mod m1 { |
| pub fn bar() {} |
| } |
| pub mod m2 { |
| pub fn bar() {} |
| } |
| "#; |
| run_compiler(test_src, |tcx| find_def_id_by_name(tcx, "missing_name")); |
| } |
| |
| #[test] |
| #[should_panic(expected = "More than one item named `some_name`")] |
| fn test_find_def_id_by_name_panic_when_multiple_items_with_matching_name() { |
| let test_src = r#" |
| pub mod m1 { |
| pub fn some_name() {} |
| } |
| pub mod m2 { |
| pub fn some_name() {} |
| } |
| "#; |
| run_compiler(test_src, |tcx| find_def_id_by_name(tcx, "some_name")); |
| } |
| |
| #[test] |
| fn test_generated_bindings_fn_success() { |
| // This test covers only a single example of a function that should get a C++ |
| // binding. Additional coverage of how items are formatted is provided by |
| // `test_format_def_...` tests. |
| let test_src = r#" |
| #[no_mangle] |
| pub extern "C" fn public_function() { |
| println!("foo"); |
| } |
| "#; |
| test_generated_bindings(test_src, |bindings| { |
| let bindings = bindings.expect("Test expects success"); |
| assert_cc_matches!( |
| bindings.h_body, |
| quote! { |
| extern "C" void public_function(); |
| } |
| ); |
| }); |
| } |
| |
| #[test] |
| fn test_generated_bindings_fn_non_pub() { |
| let test_src = r#" |
| #![allow(dead_code)] |
| extern "C" fn private_function() { |
| println!("foo"); |
| } |
| "#; |
| test_generated_bindings(test_src, |bindings| { |
| let bindings = bindings.expect("Test expects success"); |
| |
| // Non-public functions should not be present in the generated bindings. |
| assert_cc_not_matches!(bindings.h_body, quote! { private_function }); |
| }); |
| } |
| |
| #[test] |
| fn test_generated_bindings_top_level_items() { |
| let test_src = "pub fn public_function() {}"; |
| test_generated_bindings(test_src, |bindings| { |
| let bindings = bindings.expect("Test expects success"); |
| let expected_comment_txt = |
| "Automatically @generated C++ bindings for the following Rust crate:\n\ |
| rust_out"; |
| assert_cc_matches!( |
| bindings.h_body, |
| quote! { |
| __COMMENT__ #expected_comment_txt |
| ... |
| __HASH_TOKEN__ pragma once |
| ... |
| namespace rust_out { |
| ... |
| } |
| } |
| ); |
| }) |
| } |
| |
| #[test] |
| fn test_generated_bindings_unsupported_item() { |
| // This test verifies how `Err` from `format_def` is formatted as a C++ comment |
| // (in `format_crate` and `format_unsupported_def`). |
| // - This test covers only a single example of an unsupported item. Additional |
| // coverage is provided by `test_format_def_unsupported_...` tests. |
| // - This test somewhat arbitrarily chooses an example of an unsupported item, |
| // trying to pick one that 1) will never be supported (b/254104998 has some extra |
| // notes about APIs named after reserved C++ keywords) and 2) tests that the |
| // full error chain is included in the message. |
| let test_src = r#" |
| #[no_mangle] |
| pub extern "C" fn reinterpret_cast() {} |
| "#; |
| test_generated_bindings(test_src, |bindings| { |
| let bindings = bindings.expect("Test expects success"); |
| let expected_comment_txt = "Error generating bindings for `reinterpret_cast` \ |
| defined at <crubit_unittests.rs>:3:17: 3:53: \ |
| Error formatting function name: \ |
| `reinterpret_cast` is a C++ reserved keyword \ |
| and can't be used as a C++ identifier"; |
| assert_cc_matches!( |
| bindings.h_body, |
| quote! { |
| __COMMENT__ #expected_comment_txt |
| } |
| ); |
| }) |
| } |
| |
| #[test] |
| fn test_format_def_fn_extern_c_no_mangle_no_params_no_return_type() { |
| let test_src = r#" |
| #[no_mangle] |
| pub extern "C" fn public_function() {} |
| "#; |
| test_format_def(test_src, "public_function", |result| { |
| assert_cc_matches!( |
| result.expect("Test expects success here"), |
| quote! { |
| extern "C" void public_function(); |
| } |
| ); |
| }); |
| } |
| |
| #[test] |
| fn test_format_def_fn_explicit_unit_return_type() { |
| // This test is very similar to the |
| // `test_format_def_fn_extern_c_no_mangle_no_params_no_return_type` above, except that the |
| // return type is explicitly spelled out. There is no difference in `ty::FnSig` so our |
| // code behaves exactly the same, but the test has been planned based on earlier, |
| // hir-focused approach and having this extra test coverage shouldn't hurt. (`hir::FnSig` |
| // and `hir::FnRetTy` _do_ see a difference between the two tests). |
| let test_src = r#" |
| #[no_mangle] |
| pub extern "C" fn explicit_unit_return_type() -> () {} |
| "#; |
| test_format_def(test_src, "explicit_unit_return_type", |result| { |
| assert_cc_matches!( |
| result.expect("Test expects success here"), |
| quote! { |
| extern "C" void explicit_unit_return_type(); |
| } |
| ); |
| }); |
| } |
| |
| #[test] |
| fn test_format_def_fn_never_return_type() { |
| let test_src = r#" |
| #[no_mangle] |
| pub extern "C" fn never_returning_function() -> ! { |
| panic!("This function panics and therefore never returns"); |
| } |
| "#; |
| test_format_def(test_src, "never_returning_function", |result| { |
| // TODO(b/254507801): The function should be annotated with the `[[noreturn]]` |
| // attribute. |
| // TODO(b/254507801): Expect `crubit::Never` instead (see the bug for more |
| // details). |
| assert_cc_matches!( |
| result.expect("Test expects success here"), |
| quote! { |
| extern "C" void never_returning_function(); |
| } |
| ); |
| }) |
| } |
| |
| #[test] |
| fn test_format_def_fn_mangling() { |
| let test_src = r#" |
| pub extern "C" fn public_function() {} |
| "#; |
| test_format_def(test_src, "public_function", |result| { |
| let err = result.expect_err("Test expects an error here"); |
| assert_eq!(err, "Mangled or renamed symbols are not supported yet"); |
| }); |
| } |
| |
| #[test] |
| fn test_format_def_fn_export_name() { |
| let test_src = r#" |
| #[export_name = "exported_function"] |
| #[no_mangle] |
| pub extern "C" fn public_function() {} |
| "#; |
| test_format_def(test_src, "public_function", |result| { |
| let err = result.expect_err("Test expects an error here"); |
| assert_eq!(err, "Mangled or renamed symbols are not supported yet"); |
| }); |
| } |
| |
| #[test] |
| fn test_format_def_unsupported_fn_unsafe() { |
| // This tests how bindings for an `unsafe fn` are generated. |
| let test_src = r#" |
| #[no_mangle] |
| pub unsafe extern "C" fn foo() {} |
| "#; |
| test_format_def(test_src, "foo", |result| { |
| let err = result.expect_err("Test expects an error here"); |
| assert_eq!( |
| err, |
| "Bindings for `unsafe` functions \ |
| are not fully designed yet (b/254095482)" |
| ); |
| }); |
| } |
| |
| #[test] |
| fn test_format_def_fn_const() { |
| // This tests how bindings for an `const fn` are generated. |
| // |
| // Right now the `const` qualifier is ignored, but one can imagine that in the |
| // (very) long-term future such functions (including their bodies) could |
| // be translated into C++ `consteval` functions. |
| let test_src = r#" |
| pub const fn foo(i: i32) -> i32 { i * 42 } |
| "#; |
| test_format_def(test_src, "foo", |result| { |
| // TODO(lukasza): Update test expectations below once `const fn` example from |
| // the testcase doesn't just error out (and is instead supported as |
| // a non-`consteval` binding). |
| // TODO(b/254095787): Update test expectations below once `const fn` from Rust |
| // is translated into a `consteval` C++ function. |
| let err = result.expect_err("Test expects an error here"); |
| assert_eq!(err, "Non-C ABI is not supported yet (b/254097223)"); |
| }); |
| } |
| |
| #[test] |
| fn test_format_def_fn_with_c_unwind_abi() { |
| // See also https://rust-lang.github.io/rfcs/2945-c-unwind-abi.html |
| let test_src = r#" |
| #![feature(c_unwind)] |
| |
| #[no_mangle] |
| pub extern "C-unwind" fn may_throw() {} |
| "#; |
| test_format_def(test_src, "may_throw", |result| { |
| assert_cc_matches!( |
| result.expect("Test expects success here"), |
| quote! { |
| extern "C" void may_throw(); |
| } |
| ); |
| }); |
| } |
| |
| #[test] |
| fn test_format_def_fn_with_type_aliased_return_type() { |
| // Type aliases disappear at the `rustc_middle::ty::Ty` level and therefore in |
| // the short-term the generated bindings also ignore type aliases. |
| // |
| // TODO(b/254096006): Consider preserving `type` aliases when generating |
| // bindings. |
| let test_src = r#" |
| type MyTypeAlias = f64; |
| |
| #[no_mangle] |
| pub extern "C" fn type_aliased_return() -> MyTypeAlias { 42.0 } |
| "#; |
| test_format_def(test_src, "type_aliased_return", |result| { |
| assert_cc_matches!( |
| result.expect("Test expects success here"), |
| quote! { |
| extern "C" double type_aliased_return(); |
| } |
| ); |
| }); |
| } |
| |
| #[test] |
| fn test_format_def_unsupported_fn_name_is_reserved_cpp_keyword() { |
| let test_src = r#" |
| #[no_mangle] |
| pub extern "C" fn reinterpret_cast() -> () {} |
| "#; |
| test_format_def(test_src, "reinterpret_cast", |result| { |
| let err = result.expect_err("Test expects an error here"); |
| assert_eq!( |
| err, |
| "Error formatting function name: \ |
| `reinterpret_cast` is a C++ reserved keyword \ |
| and can't be used as a C++ identifier" |
| ); |
| }); |
| } |
| |
| #[test] |
| fn test_format_def_unsupported_fn_ret_type() { |
| let test_src = r#" |
| #[no_mangle] |
| pub extern "C" fn foo() -> *const i32 { std::ptr::null() } |
| "#; |
| test_format_def(test_src, "foo", |result| { |
| let err = result.expect_err("Test expects an error here"); |
| assert_eq!( |
| err, |
| "Error formatting function return type: \ |
| The following Rust type is not supported yet: *const i32" |
| ); |
| }); |
| } |
| |
| #[test] |
| fn test_format_def_unsupported_fn_with_late_bound_lifetimes() { |
| let test_src = r#" |
| pub fn foo(arg: &i32) -> &i32 { arg } |
| |
| // Lifetime inference translates the above into: |
| // pub fn foo<'a>(arg: &'a i32) -> &'a i32 { ... } |
| // leaving 'a lifetime late-bound (it is bound with a lifetime |
| // taken from each of the callsites). In other words, we can't |
| // just call `no_bound_vars` on this `FnSig`'s `Binder`. |
| "#; |
| test_format_def(test_src, "foo", |result| { |
| let err = result.expect_err("Test expects an error here"); |
| assert_eq!( |
| err, |
| "Generic functions (lifetime-generic or type-generic) are not supported yet" |
| ); |
| }); |
| } |
| |
| #[test] |
| fn test_format_def_unsupported_generic_fn() { |
| let test_src = r#" |
| use std::default::Default; |
| use std::fmt::Display; |
| pub fn generic_function<T: Default + Display>() { |
| println!("{}", T::default()); |
| } |
| "#; |
| test_format_def(test_src, "generic_function", |result| { |
| let err = result.expect_err("Test expects an error here"); |
| assert_eq!( |
| err, |
| "Generic functions (lifetime-generic or type-generic) are not supported yet" |
| ); |
| }); |
| } |
| |
| #[test] |
| fn test_format_def_unsupported_fn_async() { |
| let test_src = r#" |
| pub async fn async_function() {} |
| "#; |
| test_format_def(test_src, "async_function", |result| { |
| let err = result.expect_err("Test expects an error here"); |
| assert_eq!(err, "Non-C ABI is not supported yet (b/254097223)"); |
| }); |
| } |
| |
| #[test] |
| fn test_format_def_unsupported_fn_non_c_abi() { |
| let test_src = r#" |
| pub fn default_rust_abi_function() {} |
| "#; |
| test_format_def(test_src, "default_rust_abi_function", |result| { |
| let err = result.expect_err("Test expects an error here"); |
| assert_eq!(err, "Non-C ABI is not supported yet (b/254097223)"); |
| }) |
| } |
| |
| #[test] |
| fn test_format_def_unsupported_fn_variadic() { |
| let test_src = r#" |
| #![feature(c_variadic)] |
| |
| #[no_mangle] |
| pub unsafe extern "C" fn variadic_function(_fmt: *const u8, ...) {} |
| "#; |
| test_format_def(test_src, "variadic_function", |result| { |
| // TODO(b/254097223): Add support for variadic functions. |
| let err = result.expect_err("Test expects an error here"); |
| assert_eq!(err, "C variadic functions are not supported (b/254097223)"); |
| }); |
| } |
| |
| #[test] |
| fn test_format_def_fn_params() { |
| let test_src = r#" |
| #[allow(unused_variables)] |
| #[no_mangle] |
| pub extern "C" fn foo(b: bool, f: f64) {} |
| "#; |
| test_format_def(test_src, "foo", |result| { |
| assert_cc_matches!( |
| result.expect("Test expects success here"), |
| quote! { |
| extern "C" void foo(bool b, double f); |
| } |
| ); |
| }); |
| } |
| |
| #[test] |
| fn test_format_def_fn_param_name_reserved_keyword() { |
| let test_src = r#" |
| #[allow(unused_variables)] |
| #[no_mangle] |
| pub extern "C" fn some_function(reinterpret_cast: f64) {} |
| "#; |
| test_format_def(test_src, "some_function", |result| { |
| assert_cc_matches!( |
| result.expect("Test expects success here"), |
| quote! { |
| extern "C" void some_function(double __param_0); |
| } |
| ); |
| }); |
| } |
| |
| #[test] |
| fn test_format_def_unsupported_fn_param_type() { |
| let test_src = r#" |
| #[no_mangle] |
| pub extern "C" fn fn_with_params(_param: *const i32) {} |
| "#; |
| test_format_def(test_src, "fn_with_params", |result| { |
| let err = result.expect_err("Test expects an error here"); |
| assert_eq!(err, "Error formatting the type of parameter #0: \ |
| The following Rust type is not supported yet: \ |
| *const i32"); |
| }); |
| } |
| |
| #[test] |
| fn test_format_def_unsupported_fn_param_type_unit() { |
| let test_src = r#" |
| #[no_mangle] |
| pub fn fn_with_params(_param: ()) {} |
| "#; |
| test_format_def(test_src, "fn_with_params", |result| { |
| // TODO(b/254097223): Change the expectations once Rust-ABI functions are |
| // supported. Note that the test cannot use `extern "C"` in the |
| // meantime, because `()` is not FFI-safe (i.e. Rust won't allow |
| // using it with `extern "C"`). |
| let err = result.expect_err("Test expects an error here"); |
| assert_eq!(err, "Non-C ABI is not supported yet (b/254097223)"); |
| }); |
| } |
| |
| #[test] |
| fn test_format_def_unsupported_fn_param_type_never() { |
| let test_src = r#" |
| #![feature(never_type)] |
| |
| #[no_mangle] |
| pub extern "C" fn fn_with_params(_param: !) {} |
| "#; |
| test_format_def(test_src, "fn_with_params", |result| { |
| let err = result.expect_err("Test expects an error here"); |
| assert_eq!( |
| err, |
| "Error formatting the type of parameter #0: \ |
| The never type `!` is only supported as a return type (b/254507801)" |
| ); |
| }); |
| } |
| |
| #[test] |
| fn test_format_def_unsupported_hir_item_kind() { |
| let test_src = r#" |
| pub struct SomeStruct(i32); |
| "#; |
| test_format_def(test_src, "SomeStruct", |result| { |
| let err = result.expect_err("Test expects an error here"); |
| assert_eq!(err, "Unsupported rustc_hir::hir::ItemKind: struct"); |
| }); |
| } |
| |
| #[test] |
| fn test_format_ret_ty_successes() { |
| // Test coverage for cases where `format_ret_ty` returns an `Ok(...)`. |
| // Additional testcases are covered by `test_format_ty_successes` |
| // (because `format_ret_ty` delegates most cases to `format_ty`). |
| let testcases = [ |
| // ( <Rust type>, <expected C++ type> ) |
| ("bool", "bool"), // TyKind::Bool |
| ("()", "void"), |
| // TODO(b/254507801): Expect `crubit::Never` instead (see the bug for more |
| // details). |
| ("!", "void"), |
| ]; |
| test_ty(&testcases, |desc, ty, expected| { |
| let actual = format_ret_ty(ty).unwrap().to_string(); |
| let expected = expected.parse::<TokenStream>().unwrap().to_string(); |
| assert_eq!(actual, expected, "{desc}"); |
| }); |
| } |
| |
| #[test] |
| fn test_format_ty_successes() { |
| // Test coverage for cases where `format_ty` returns an `Ok(...)`. |
| let testcases = [ |
| // ( <Rust type>, <expected C++ type> ) |
| ("bool", "bool"), // TyKind::Bool |
| ("f32", "float"), // TyKind::Float(ty::FloatTy::F32) |
| ("f64", "double"), // TyKind::Float(ty::FloatTy::F64) |
| // Extra parens/sugar are expected to be ignored: |
| ("(bool)", "bool"), |
| ]; |
| test_ty(&testcases, |desc, ty, expected| { |
| let actual = format_ty(ty).unwrap().to_string(); |
| let expected = expected.parse::<TokenStream>().unwrap().to_string(); |
| assert_eq!(actual, expected, "{desc}"); |
| }); |
| } |
| |
| #[test] |
| fn test_format_ty_failures() { |
| // This test provides coverage for cases where `format_ty` returns an |
| // `Err(...)`. |
| // |
| // TODO(lukasza): Add test coverage for: |
| // - TyKind::Adt (structs, unions, enums, etc.) |
| // - TyKind::Bound |
| // - TyKind::Dynamic (`dyn Eq`) |
| // - TyKind::Foreign (`extern type T`) |
| // - https://doc.rust-lang.org/beta/unstable-book/language-features/generators.html: |
| // TyKind::Generator, TyKind::GeneratorWitness |
| // - TyKind::Param |
| // - TyKind::Placeholder |
| // - TyKind::Projection |
| // |
| // It seems okay to have no test coverage for now for the following types (which |
| // should never be encountered when generating bindings and where |
| // `format_ty` should panic): |
| // - TyKind::Closure |
| // - TyKind::Error |
| // - TyKind::FnDef |
| // - TyKind::Infer */ |
| let testcases = [ |
| // ( <Rust type>, <expected error message> ) |
| ( |
| "()", // Empty TyKind::Tuple |
| "The unit type `()` / `void` is only supported as a return type" |
| ), |
| ( |
| // TODO(b/254507801): Expect `crubit::Never` instead (see the bug for more |
| // details). |
| "!", // TyKind::Never |
| "The never type `!` is only supported as a return type (b/254507801)" |
| ), |
| ( |
| "(i32, i32)", // Non-empty TyKind::Tuple |
| "Tuples are not supported yet: (i32, i32) (b/254099023)", |
| ), |
| ( |
| "char", // TyKind::Char |
| "No support yet for `#include`ing C++ equivalent of `char` (b/254094545)", |
| ), |
| ( |
| "i32", // TyKind::Int |
| "No support yet for `#include`ing C++ equivalent of `i32` (b/254094545)", |
| ), |
| ( |
| "u32", // TyKind::UInt |
| "No support yet for `#include`ing C++ equivalent of `u32` (b/254094545)", |
| ), |
| ( |
| "*const i32", // TyKind::Ptr |
| "The following Rust type is not supported yet: *const i32", |
| ), |
| ( |
| "&'static i32", // TyKind::Ref |
| "The following Rust type is not supported yet: &'static i32", |
| ), |
| ( |
| "[i32; 42]", // TyKind::Array |
| "The following Rust type is not supported yet: [i32; 42]", |
| ), |
| ( |
| "&'static [i32]", // TyKind::Slice (nested underneath TyKind::Ref) |
| "The following Rust type is not supported yet: &'static [i32]", |
| ), |
| ( |
| "&'static str", // TyKind::Str (nested underneath TyKind::Ref) |
| "The following Rust type is not supported yet: &'static str", |
| ), |
| ( |
| "impl Eq", // TyKind::Opaque |
| "The following Rust type is not supported yet: impl std::cmp::Eq", |
| ), |
| ( |
| "fn(i32) -> i32", // TyKind::FnPtr |
| "The following Rust type is not supported yet: fn(i32) -> i32", |
| ), |
| // TODO(b/254094650): Consider mapping this to Clang's (and GCC's) `__int128` |
| // or to `absl::in128`. |
| ("i128", "C++ doesn't have a standard equivalent of `i128` (b/254094650)"), |
| ("u128", "C++ doesn't have a standard equivalent of `u128` (b/254094650)"), |
| ]; |
| test_ty(&testcases, |desc, ty, expected_err| { |
| let anyhow_err = format_ty(ty).unwrap_err(); |
| let actual_err = format!("{anyhow_err:#}"); |
| assert_eq!(&actual_err, *expected_err, "{desc}"); |
| }); |
| } |
| |
| fn test_ty<TestFn, Expectation>(testcases: &[(&str, Expectation)], test_fn: TestFn) |
| where |
| TestFn: Fn(/* testcase_description: */ &str, Ty, &Expectation) -> () + Sync, |
| Expectation: Sync, |
| { |
| for (index, (input, expected)) in testcases.into_iter().enumerate() { |
| let desc = format!("test #{index}: test input: `{input}`"); |
| let input = { |
| let ty_tokens: TokenStream = input.parse().unwrap(); |
| let input = quote! { |
| #![allow(unused_parens)] |
| pub fn test_function() -> #ty_tokens { panic!("") } |
| }; |
| input.to_string() |
| }; |
| run_compiler(input, |tcx| { |
| let def_id = find_def_id_by_name(tcx, "test_function"); |
| let ty = tcx.fn_sig(def_id.to_def_id()).no_bound_vars().unwrap().output(); |
| test_fn(&desc, ty, expected); |
| }); |
| } |
| } |
| |
| /// Tests invoking `format_def` on the item with the specified `name` from |
| /// the given Rust `source`. Returns the result of calling |
| /// `test_function` with `format_def`'s result as an argument. |
| /// (`test_function` should typically `assert!` that it got the expected |
| /// result from `format_def`.) |
| fn test_format_def<F, T>(source: &str, name: &str, test_function: F) -> T |
| where |
| F: FnOnce(Result<TokenStream, String>) -> T + Send, |
| T: Send, |
| { |
| run_compiler(source, |tcx| { |
| let def_id = find_def_id_by_name(tcx, name); |
| let result = format_def(tcx, def_id); |
| |
| // https://docs.rs/anyhow/latest/anyhow/struct.Error.html#display-representations says: |
| // To print causes as well [...], use the alternate selector “{:#}”. |
| let result = result.map_err(|anyhow_err| format!("{anyhow_err:#}")); |
| |
| test_function(result) |
| }) |
| } |
| |
| /// Finds the definition id of a Rust item with the specified `name`. |
| /// Panics if no such item is found, or if there is more than one match. |
| fn find_def_id_by_name(tcx: TyCtxt, name: &str) -> LocalDefId { |
| let hir_items = || tcx.hir().items().map(|item_id| tcx.hir().item(item_id)); |
| let items_with_matching_name = |
| hir_items().filter(|item| item.ident.name.as_str() == name).collect_vec(); |
| match items_with_matching_name.as_slice() { |
| &[] => { |
| let found_names = hir_items() |
| .map(|item| item.ident.name.as_str()) |
| .filter(|s| !s.is_empty()) |
| .sorted() |
| .dedup() |
| .map(|name| format!("`{name}`")) |
| .collect_vec(); |
| panic!("No items named `{}`.\nInstead found:\n{}", name, found_names.join(",\n")); |
| } |
| &[item] => item.def_id.def_id, |
| _ => panic!("More than one item named `{name}`"), |
| } |
| } |
| |
| /// Tests invoking `GeneratedBindings::generate` on the given Rust `source`. |
| /// Returns the result of calling `test_function` with the generated |
| /// bindings as an argument. (`test_function` should typically `assert!` |
| /// that it got the expected `GeneratedBindings`.) |
| fn test_generated_bindings<F, T>(source: &str, test_function: F) -> T |
| where |
| F: FnOnce(Result<GeneratedBindings>) -> T + Send, |
| T: Send, |
| { |
| run_compiler(source, |tcx| test_function(GeneratedBindings::generate(tcx))) |
| } |
| |
| /// Invokes the Rust compiler on the given Rust `source` and then calls `f` |
| /// on the `TyCtxt` representation of the compiled `source`. |
| fn run_compiler<F, T>(source: impl Into<String>, f: F) -> T |
| where |
| F: for<'tcx> FnOnce(TyCtxt<'tcx>) -> T + Send, |
| T: Send, |
| { |
| use rustc_session::config::{ |
| CodegenOptions, CrateType, Input, Options, OutputType, OutputTypes, |
| }; |
| |
| const TEST_FILENAME: &str = "crubit_unittests.rs"; |
| |
| // Setting `output_types` that will trigger code gen - otherwise some parts of |
| // the analysis will be missing (e.g. `tcx.exported_symbols()`). |
| // The choice of `Bitcode` is somewhat arbitrary (e.g. `Assembly`, |
| // `Mir`, etc. would also trigger code gen). |
| let output_types = OutputTypes::new(&[(OutputType::Bitcode, None /* PathBuf */)]); |
| |
| let opts = Options { |
| crate_types: vec![CrateType::Rlib], // Test inputs simulate library crates. |
| maybe_sysroot: Some(get_sysroot_for_testing()), |
| output_types, |
| edition: rustc_span::edition::Edition::Edition2021, |
| unstable_features: rustc_feature::UnstableFeatures::Allow, |
| lint_opts: vec![ |
| ("warnings".to_string(), rustc_lint_defs::Level::Deny), |
| ("stable_features".to_string(), rustc_lint_defs::Level::Allow), |
| ], |
| cg: CodegenOptions { |
| panic: Some(rustc_target::spec::PanicStrategy::Abort), |
| ..Default::default() |
| }, |
| ..Default::default() |
| }; |
| |
| let config = rustc_interface::interface::Config { |
| opts, |
| crate_cfg: Default::default(), |
| crate_check_cfg: Default::default(), |
| input: Input::Str { |
| name: rustc_span::FileName::Custom(TEST_FILENAME.to_string()), |
| input: source.into(), |
| }, |
| input_path: None, |
| output_file: None, |
| output_dir: None, |
| file_loader: None, |
| lint_caps: Default::default(), |
| parse_sess_created: None, |
| register_lints: None, |
| override_queries: None, |
| make_codegen_backend: None, |
| registry: rustc_errors::registry::Registry::new(rustc_error_codes::DIAGNOSTICS), |
| }; |
| |
| rustc_interface::interface::run_compiler(config, |compiler| { |
| compiler.enter(|queries| { |
| use rustc_interface::interface::Result; |
| let result: Result<Result<()>> = super::enter_tcx(queries, |tcx| { |
| // Explicitly force full `analysis` stage to detect compilation |
| // errors that the earlier stages might miss. This helps ensure that the |
| // test inputs are valid Rust (even if `f` wouldn't |
| // have triggered full analysis). |
| tcx.analysis(()) |
| }); |
| |
| // Flatten the outer and inner results into a single result. (outer result |
| // comes from `enter_tcx`; inner result comes from `analysis`). |
| // |
| // TODO(lukasza): Use `Result::flatten` API when it gets stabilized. See also |
| // https://github.com/rust-lang/rust/issues/70142 |
| let result: Result<()> = result.and_then(|result| result); |
| |
| // `analysis` might succeed even if there are some lint / warning errors. |
| // Detecting these requires explicitly checking `compile_status`. |
| let result: Result<()> = result.and_then(|()| compiler.session().compile_status()); |
| |
| // Run the provided callback. |
| let result: Result<T> = result.and_then(|()| super::enter_tcx(queries, f)); |
| result.expect("Test inputs shouldn't cause compilation errors") |
| }) |
| }) |
| } |
| } |
