macros: add compilation tests

Use the [trybuild](https://github.com/dtolnay/trybuild) crate to test
the `unsafe_guid` and `entry` macros. The compilation output is compared
against expected output to check the various error cases in the macros,
which allows detailed tests covering things like the specific error
messages and the associated spans.

Author: nicholasbishop

uefi-macros/Cargo.toml

@@ -22,3 +22,7 @@ proc-macro = true
 proc-macro2 = "1.0.28"
 quote = "1.0.9"
 syn = { version = "1.0.75", features = ["full"] }
+
+[dev-dependencies]
+trybuild = "1.0.45"
+uefi = { version = "0.12.0", default-features = false }

uefi-macros/tests/cargo_wrapper

@@ -0,0 +1,2 @@
+#!/bin/sh
+cargo -Zbuild-std=std "$@"

uefi-macros/tests/compilation.rs

@@ -0,0 +1,20 @@
+use std::env;
+
+#[test]
+fn ui() {
+    let t = trybuild::TestCases::new();
+
+    // Due to the way trybuild compiles the input files, `no_std`
+    // doesn't work. So, since -Zbuild-std is enabled in the cargo
+    // config file in the root of the crate we need to also build the
+    // std crate for these tests. This wrapper script adds the necessary
+    // argument when trybuild invokes cargo.
+    let cargo_wrapper = env::current_exe()
+        .unwrap()
+        .parent()
+        .unwrap()
+        .join("../../../../uefi-macros/tests/cargo_wrapper");
+    env::set_var("CARGO", cargo_wrapper);
+
+    t.compile_fail("tests/ui/*.rs");
+}

uefi-macros/tests/ui/entry.rs

@@ -0,0 +1,45 @@
+#![no_main]
+#![feature(abi_efiapi)]
+
+use uefi::prelude::*;
+use uefi_macros::entry;
+
+#[entry]
+fn good_entry(_handle: Handle, _st: SystemTable<Boot>) -> Status {
+    Status::SUCCESS
+}
+
+#[entry(some_arg)]
+fn bad_attr_arg(_handle: Handle, _st: SystemTable<Boot>) -> Status {
+    Status::SUCCESS
+}
+
+#[entry]
+extern "C" fn bad_abi_modifier(_handle: Handle, _st: SystemTable<Boot>) -> Status {
+    Status::SUCCESS
+}
+
+#[entry]
+async fn bad_async(_handle: Handle, _st: SystemTable<Boot>) -> Status {
+    Status::SUCCESS
+}
+
+#[entry]
+fn bad_const(_handle: Handle, _st: SystemTable<Boot>) -> Status {
+    Status::SUCCESS
+}
+
+#[entry]
+fn bad_generic<T>(_handle: Handle, _st: SystemTable<Boot>) -> Status {
+    Status::SUCCESS
+}
+
+#[entry]
+fn bad_args(_handle: Handle, _st: SystemTable<Boot>, _x: usize) -> bool {
+    false
+}
+
+#[entry]
+fn bad_return_type(_handle: Handle, _st: SystemTable<Boot>) -> bool {
+    false
+}

uefi-macros/tests/ui/entry.stderr

@@ -0,0 +1,41 @@
+error: Entry attribute accepts no arguments
+  --> $DIR/entry.rs:12:9
+   |
+12 | #[entry(some_arg)]
+   |         ^^^^^^^^
+
+error: Entry method must have no ABI modifier
+  --> $DIR/entry.rs:18:1
+   |
+18 | extern "C" fn bad_abi_modifier(_handle: Handle, _st: SystemTable<Boot>) -> Status {
+   | ^^^^^^^^^^
+
+error: Entry method should not be async
+  --> $DIR/entry.rs:23:1
+   |
+23 | async fn bad_async(_handle: Handle, _st: SystemTable<Boot>) -> Status {
+   | ^^^^^
+
+error: Entry method should not be generic
+  --> $DIR/entry.rs:33:16
+   |
+33 | fn bad_generic<T>(_handle: Handle, _st: SystemTable<Boot>) -> Status {
+   |                ^
+
+error[E0308]: mismatched types
+  --> $DIR/entry.rs:38:4
+   |
+38 | fn bad_args(_handle: Handle, _st: SystemTable<Boot>, _x: usize) -> bool {
+   |    ^^^^^^^^ incorrect number of function parameters
+   |
+   = note: expected fn pointer `extern "efiapi" fn(uefi::Handle, uefi::table::SystemTable<uefi::table::Boot>) -> uefi::Status`
+                 found fn item `extern "efiapi" fn(uefi::Handle, uefi::table::SystemTable<uefi::table::Boot>, usize) -> bool {bad_args}`
+
+error[E0308]: mismatched types
+  --> $DIR/entry.rs:43:4
+   |
+43 | fn bad_return_type(_handle: Handle, _st: SystemTable<Boot>) -> bool {
+   |    ^^^^^^^^^^^^^^^ expected struct `uefi::Status`, found `bool`
+   |
+   = note: expected fn pointer `extern "efiapi" fn(uefi::Handle, uefi::table::SystemTable<_>) -> uefi::Status`
+                 found fn item `extern "efiapi" fn(uefi::Handle, uefi::table::SystemTable<_>) -> bool {bad_return_type}`

uefi-macros/tests/ui/guid.rs

@@ -0,0 +1,19 @@
+use uefi_macros::unsafe_guid;
+
+// The GUID here is OK.
+#[unsafe_guid("aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa")]
+struct Good;
+
+// Fail because the length is wrong.
+#[unsafe_guid("aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaa")]
+struct TooShort;
+
+// Error span should point to the second group.
+#[unsafe_guid("aaaaaaaa-Gaaa-aaaa-aaaa-aaaaaaaaaaaa")]
+struct BadHexGroup2;
+
+// Error span should point to the fifth group.
+#[unsafe_guid("aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaG")]
+struct BadHexGroup5;
+
+fn main() {}

uefi-macros/tests/ui/guid.stderr

@@ -0,0 +1,17 @@
+error: "aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaa" is not a canonical GUID string (expected 36 bytes, found 35)
+ --> $DIR/guid.rs:8:15
+  |
+8 | #[unsafe_guid("aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaa")]
+  |               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: GUID component "Gaaa" is not a hexadecimal number
+  --> $DIR/guid.rs:12:25
+   |
+12 | #[unsafe_guid("aaaaaaaa-Gaaa-aaaa-aaaa-aaaaaaaaaaaa")]
+   |                         ^^^^
+
+error: GUID component "aaaaaaaaaaaG" is not a hexadecimal number
+  --> $DIR/guid.rs:16:40
+   |
+16 | #[unsafe_guid("aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaG")]
+   |                                        ^^^^^^^^^^^^