relax checks of the signatures of entry and the exceptions

Author: japaric

cortex-m-rt/ci/script.sh

@@ -13,12 +13,18 @@ main() {
 
     local examples=(
         alignment
+        divergent-default-handler
+        divergent-exception
         entry-static
         main
         minimal
         override-exception
         pre_init
         state
+        unsafe-default-handler
+        unsafe-hard-fault
+        unsafe-entry
+        unsafe-exception
     )
     local fail_examples=(
         data_overflow

cortex-m-rt/tests/compile-fail/default-handler-bad-signature-3.rs renamed to cortex-m-rt/examples/divergent-default-handler.rs

@@ -1,3 +1,5 @@
+#![deny(unsafe_code)]
+#![deny(warnings)]
 #![no_main]
 #![no_std]
 
@@ -11,8 +13,7 @@ fn foo() -> ! {
     loop {}
 }
 
-#[exception] //~ ERROR custom attribute panicked
-//~^ HELP `DefaultHandler` exception must have signature `fn(i16)`
+#[exception]
 fn DefaultHandler(_irqn: i16) -> ! {
     loop {}
 }

cortex-m-rt/tests/compile-fail/exception-bad-signature-3.rs renamed to cortex-m-rt/examples/divergent-exception.rs

@@ -1,3 +1,4 @@
+#![deny(warnings)]
 #![no_main]
 #![no_std]
 
@@ -11,8 +12,7 @@ fn foo() -> ! {
     loop {}
 }
 
-#[exception] //~ ERROR custom attribute panicked
-//~^ HELP `#[exception]` functions other than `DefaultHandler` and `HardFault` must have signature `fn()`
+#[exception]
 fn SysTick() -> ! {
     loop {}
 }

cortex-m-rt/tests/compile-fail/default-handler-bad-signature-2.rs renamed to cortex-m-rt/examples/unsafe-default-handler.rs

@@ -1,3 +1,4 @@
+#![deny(warnings)]
 #![no_main]
 #![no_std]
 
@@ -11,6 +12,5 @@ fn foo() -> ! {
     loop {}
 }
 
-#[exception] //~ ERROR custom attribute panicked
-//~^ HELP `DefaultHandler` exception must have signature `fn(i16)`
+#[exception]
 unsafe fn DefaultHandler(_irqn: i16) {}

cortex-m-rt/examples/unsafe-entry.rs

@@ -0,0 +1,13 @@
+#![deny(warnings)]
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_semihosting;
+
+use cortex_m_rt::entry;
+
+#[entry]
+unsafe fn foo() -> ! {
+    loop {}
+}

cortex-m-rt/tests/compile-fail/exception-bad-signature-2.rs renamed to cortex-m-rt/examples/unsafe-exception.rs

@@ -1,3 +1,4 @@
+#![deny(warnings)]
 #![no_main]
 #![no_std]
 
@@ -11,6 +12,5 @@ fn foo() -> ! {
     loop {}
 }
 
-#[exception] //~ ERROR custom attribute panicked
-//~^ HELP `#[exception]` functions other than `DefaultHandler` and `HardFault` must have signature `fn()`
+#[exception]
 unsafe fn SysTick() {}

cortex-m-rt/tests/compile-fail/hard-fault-bad-signature-2.rs renamed to cortex-m-rt/examples/unsafe-hard-fault.rs

@@ -1,3 +1,4 @@
+#![deny(warnings)]
 #![no_main]
 #![no_std]
 
@@ -11,8 +12,7 @@ fn foo() -> ! {
     loop {}
 }
 
-#[exception] //~ ERROR custom attribute panicked
-//~^ HELP `HardFault` exception must have signature `fn(&ExceptionFrame) -> !`
+#[exception]
 unsafe fn HardFault(_ef: &ExceptionFrame) -> ! {
     loop {}
 }

cortex-m-rt/macros/src/lib.rs

@@ -22,7 +22,7 @@ use proc_macro::TokenStream;
 /// the case of the `thumbv7em-none-eabihf` target the FPU will also be enabled before the function
 /// is called.
 ///
-/// The type of the specified function must be `fn() -> !` (never ending function)
+/// The type of the specified function must be `[unsafe] fn() -> !` (never ending function)
 ///
 /// # Properties
 ///
@@ -76,7 +76,6 @@ pub fn entry(args: TokenStream, input: TokenStream) -> TokenStream {
     assert!(
         f.constness.is_none()
             && f.vis == Visibility::Inherited
-            && f.unsafety.is_none()
             && f.abi.is_none()
             && f.decl.inputs.is_empty()
             && f.decl.generics.params.is_empty()
@@ -89,7 +88,7 @@ pub fn entry(args: TokenStream, input: TokenStream) -> TokenStream {
                     _ => false,
                 },
             },
-        "`#[entry]` function must have signature `fn() -> !`"
+        "`#[entry]` function must have signature `[unsafe] fn() -> !`"
     );
 
     assert!(
@@ -173,19 +172,19 @@ pub fn entry(args: TokenStream, input: TokenStream) -> TokenStream {
 /// # Usage
 ///
 /// `#[exception] fn HardFault(..` sets the hard fault handler. The handler must have signature
-/// `fn(&ExceptionFrame) -> !`. This handler is not allowed to return as that can cause undefined
-/// behavior.
+/// `[unsafe] fn(&ExceptionFrame) -> !`. This handler is not allowed to return as that can cause
+/// undefined behavior.
 ///
 /// `#[exception] fn DefaultHandler(..` sets the *default* handler. All exceptions which have not
 /// been assigned a handler will be serviced by this handler. This handler must have signature
-/// `fn(irqn: i16)`. `irqn` is the IRQ number (See CMSIS); `irqn` will be a negative number when the
-/// handler is servicing a core exception; `irqn` will be a positive number when the handler is
-/// servicing a device specific exception (interrupt).
+/// `[unsafe] fn(irqn: i16) [-> !]`. `irqn` is the IRQ number (See CMSIS); `irqn` will be a negative
+/// number when the handler is servicing a core exception; `irqn` will be a positive number when the
+/// handler is servicing a device specific exception (interrupt).
 ///
 /// `#[exception] fn Name(..` overrides the default handler for the exception with the given `Name`.
-/// When overriding these other exception it's possible to add state to them by declaring `static
-/// mut` variables at the beginning of the body of the function. These variables will be safe to
-/// access from the function body.
+/// These handlers must have signature `[unsafe] fn() [-> !]`. When overriding these other exception
+/// it's possible to add state to them by declaring `static mut` variables at the beginning of the
+/// body of the function. These variables will be safe to access from the function body.
 ///
 /// # Properties
 ///
@@ -284,7 +283,6 @@ pub fn exception(args: TokenStream, input: TokenStream) -> TokenStream {
             assert!(
                 f.constness.is_none()
                     && f.vis == Visibility::Inherited
-                    && f.unsafety.is_none()
                     && f.abi.is_none()
                     && f.decl.inputs.len() == 1
                     && f.decl.generics.params.is_empty()
@@ -294,10 +292,11 @@ pub fn exception(args: TokenStream, input: TokenStream) -> TokenStream {
                         ReturnType::Default => true,
                         ReturnType::Type(_, ref ty) => match **ty {
                             Type::Tuple(ref tuple) => tuple.elems.is_empty(),
+                            Type::Never(..) => true,
                             _ => false,
                         },
                     },
-                "`DefaultHandler` exception must have signature `fn(i16)`"
+                "`DefaultHandler` exception must have signature `[unsafe] fn(i16) [-> !]`"
             );
 
             let arg = match f.decl.inputs[0] {
@@ -323,7 +322,6 @@ pub fn exception(args: TokenStream, input: TokenStream) -> TokenStream {
             assert!(
                 f.constness.is_none()
                     && f.vis == Visibility::Inherited
-                    && f.unsafety.is_none()
                     && f.abi.is_none()
                     && f.decl.inputs.len() == 1
                     && match f.decl.inputs[0] {
@@ -345,7 +343,7 @@ pub fn exception(args: TokenStream, input: TokenStream) -> TokenStream {
                             _ => false,
                         },
                     },
-                "`HardFault` exception must have signature `fn(&ExceptionFrame) -> !`"
+                "`HardFault` exception must have signature `[unsafe] fn(&ExceptionFrame) -> !`"
             );
 
             let arg = match f.decl.inputs[0] {
@@ -372,7 +370,6 @@ pub fn exception(args: TokenStream, input: TokenStream) -> TokenStream {
             assert!(
                 f.constness.is_none()
                     && f.vis == Visibility::Inherited
-                    && f.unsafety.is_none()
                     && f.abi.is_none()
                     && f.decl.inputs.is_empty()
                     && f.decl.generics.params.is_empty()
@@ -382,11 +379,12 @@ pub fn exception(args: TokenStream, input: TokenStream) -> TokenStream {
                         ReturnType::Default => true,
                         ReturnType::Type(_, ref ty) => match **ty {
                             Type::Tuple(ref tuple) => tuple.elems.is_empty(),
+                            Type::Never(..) => true,
                             _ => false,
                         },
                     },
                 "`#[exception]` functions other than `DefaultHandler` and `HardFault` must \
-                 have signature `fn()`"
+                 have signature `[unsafe] fn() [-> !]`"
             );
 
             let (statics, stmts) = extract_static_muts(stmts);

cortex-m-rt/tests/compile-fail/default-handler-bad-signature-1.rs

@@ -12,5 +12,5 @@ fn foo() -> ! {
 }
 
 #[exception] //~ ERROR custom attribute panicked
-//~^ HELP `DefaultHandler` exception must have signature `fn(i16)`
+//~^ HELP `DefaultHandler` exception must have signature `[unsafe] fn(i16) [-> !]`
 fn DefaultHandler(_irqn: i16, undef: u32) {}

cortex-m-rt/tests/compile-fail/entry-bad-signature-1.rs

@@ -7,5 +7,5 @@ extern crate panic_semihosting;
 use cortex_m_rt::entry;
 
 #[entry] //~ ERROR custom attribute panicked
-//~^ HELP `#[entry]` function must have signature `fn() -> !`
+//~^ HELP `#[entry]` function must have signature `[unsafe] fn() -> !`
 fn foo() {}

cortex-m-rt/tests/compile-fail/entry-bad-signature-2.rs

@@ -7,5 +7,5 @@ extern crate panic_semihosting;
 use cortex_m_rt::entry;
 
 #[entry] //~ ERROR custom attribute panicked
-//~^ HELP `#[entry]` function must have signature `fn() -> !`
+//~^ HELP `#[entry]` function must have signature `[unsafe] fn() -> !`
 fn foo(undef: i32) -> ! {}

cortex-m-rt/tests/compile-fail/entry-bad-signature-3.rs

@@ -7,7 +7,7 @@ extern crate panic_semihosting;
 use cortex_m_rt::entry;
 
 #[entry] //~ ERROR custom attribute panicked
-//~^ HELP `#[entry]` function must have signature `fn() -> !`
-unsafe fn foo() -> ! {
+//~^ HELP `#[entry]` function must have signature `[unsafe] fn() -> !`
+extern "C" fn foo() -> ! {
     loop {}
 }

cortex-m-rt/tests/compile-fail/entry-bad-signature-4.rs

@@ -12,5 +12,5 @@ fn foo() -> ! {
 }
 
 #[exception] //~ ERROR custom attribute panicked
-//~^ HELP `#[exception]` functions other than `DefaultHandler` and `HardFault` must have signature `fn()`
+//~^ HELP `#[exception]` functions other than `DefaultHandler` and `HardFault` must have signature `[unsafe] fn() [-> !]`
 fn SysTick(undef: u32) {}

cortex-m-rt/tests/compile-fail/exception-bad-signature-1.rs

@@ -12,7 +12,7 @@ fn foo() -> ! {
 }
 
 #[exception] //~ ERROR custom attribute panicked
-//~^ HELP `HardFault` exception must have signature `fn(&ExceptionFrame) -> !`
+//~^ HELP `HardFault` exception must have signature `[unsafe] fn(&ExceptionFrame) -> !`
 fn HardFault(_ef: &ExceptionFrame, undef: u32) -> ! {
     loop {}
 }