Expand macro for interrupt

riscv-pac/macros/src/lib.rs

@@ -6,72 +6,214 @@ extern crate syn;
 use proc_macro::TokenStream;
 use proc_macro2::TokenStream as TokenStream2;
 use quote::quote;
+use std::collections::HashMap;
 use std::str::FromStr;
-use syn::{parse_macro_input, Data, DeriveInput, Ident};
+use syn::{
+    parse::{Parse, ParseStream},
+    parse_macro_input,
+    spanned::Spanned,
+    Data, DeriveInput, Ident, Token,
+};
 
-struct PacNumberEnum {
+/// Traits that can be implemented using the `pac_enum` macro
+enum PacTrait {
+    Exception,
+    Interrupt(InterruptType),
+    Priority,
+    HartId,
+}
+
+impl PacTrait {
+    /// Returns a token stream representing the trait name
+    fn trait_name(&self) -> TokenStream2 {
+        match self {
+            Self::Exception => quote!(ExceptionNumber),
+            Self::Interrupt(_) => quote!(InterruptNumber),
+            Self::Priority => quote!(PriorityNumber),
+            Self::HartId => quote!(HartIdNumber),
+        }
+    }
+
+    /// Returns a token stream representing the data type used to represent the number
+    fn num_type(&self) -> TokenStream2 {
+        match self {
+            Self::Exception => quote!(usize),
+            Self::Interrupt(_) => quote!(usize),
+            Self::Priority => quote!(u8),
+            Self::HartId => quote!(u16),
+        }
+    }
+
+    /// Returns a token stream representing the name of the constant that holds the maximum number
+    fn const_name(&self) -> TokenStream2 {
+        match self {
+            Self::Exception => quote!(MAX_EXCEPTION_NUMBER),
+            Self::Interrupt(_) => quote!(MAX_INTERRUPT_NUMBER),
+            Self::Priority => quote!(MAX_PRIORITY_NUMBER),
+            Self::HartId => quote!(MAX_HART_ID_NUMBER),
+        }
+    }
+}
+
+impl Parse for PacTrait {
+    fn parse(input: ParseStream) -> syn::Result<Self> {
+        input.parse::<Token![unsafe]>()?;
+        let trait_name: TokenStream2 = input.parse()?;
+        match trait_name.to_string().as_str() {
+            "ExceptionNumber" => Ok(Self::Exception),
+            "CoreInterruptNumber" => Ok(Self::Interrupt(InterruptType::Core)),
+            "ExternalInterruptNumber" => Ok(Self::Interrupt(InterruptType::External)),
+            "PriorityNumber" => Ok(Self::Priority),
+            "HartIdNumber" => Ok(Self::HartId),
+            _ => Err(syn::Error::new(
+                trait_name.span(),
+                "Unknown trait name. Expected: 'ExceptionNumber', 'CoreInterruptNumber', 'ExternalInterruptNumber', 'PriorityNumber', or 'HartIdNumber'",
+            )),
+        }
+    }
+}
+
+/// Marker traits for interrupts
+enum InterruptType {
+    Core,
+    External,
+}
+
+impl InterruptType {
+    /// Returns a token stream representing the name of the marker trait
+    fn marker_trait_name(&self) -> TokenStream2 {
+        match self {
+            Self::Core => quote!(CoreInterruptNumber),
+            Self::External => quote!(ExternalInterruptNumber),
+        }
+    }
+
+    /// Returns a token stream representing the name of the array of interrupt service routines
+    fn isr_array_name(&self) -> TokenStream2 {
+        match self {
+            Self::Core => quote!(__CORE_INTERRUPTS),
+            Self::External => quote!(__EXTERNAL_INTERRUPTS),
+        }
+    }
+
+    /// Returns a token stream representing the name of the interrupt dispatch function
+    fn dispatch_fn_name(&self) -> TokenStream2 {
+        match self {
+            Self::Core => quote!(_dispatch_core_interrupt),
+            Self::External => quote!(_dispatch_external_interrupt),
+        }
+    }
+}
+
+/// Struct containing the information needed to implement the `riscv-pac` traits for an enum
+struct PacEnumItem {
+    /// The name of the enum
     name: Ident,
-    numbers: Vec<(Ident, usize)>,
+    /// The maximum discriminant value
+    max_number: usize,
+    /// A map from discriminant values to variant names
+    numbers: HashMap<usize, Ident>,
 }
 
-impl PacNumberEnum {
+impl PacEnumItem {
     fn new(input: &DeriveInput) -> Self {
         let name = input.ident.clone();
+        let (mut numbers, mut max_number) = (HashMap::new(), 0);
 
         let variants = match &input.data {
             Data::Enum(data) => &data.variants,
             _ => panic!("Input is not an enum"),
         };
-        let numbers = variants
-            .iter()
-            .map(|variant| {
-                let ident = &variant.ident;
-                let value = match &variant.discriminant {
-                    Some(d) => match &d.1 {
-                        syn::Expr::Lit(expr_lit) => match &expr_lit.lit {
-                            syn::Lit::Int(lit_int) => match lit_int.base10_parse::<usize>() {
-                                Ok(num) => num,
-                                Err(_) => {
-                                    panic!("All variant discriminants must be unsigned integers")
-                                }
-                            },
-                            _ => panic!("All variant discriminants must be unsigned integers"),
+        for v in variants.iter() {
+            let ident = v.ident.clone();
+            let value = match &v.discriminant {
+                Some(d) => match &d.1 {
+                    syn::Expr::Lit(expr_lit) => match &expr_lit.lit {
+                        syn::Lit::Int(lit_int) => match lit_int.base10_parse::<usize>() {
+                            Ok(num) => num,
+                            Err(_) => {
+                                panic!("All variant discriminants must be unsigned integers")
+                            }
                         },
                         _ => panic!("All variant discriminants must be unsigned integers"),
                     },
-                    _ => panic!("Variant must have a discriminant"),
-                };
-                (ident.clone(), value)
-            })
-            .collect();
+                    _ => panic!("All variant discriminants must be unsigned integers"),
+                },
+                _ => panic!("Variant must have a discriminant"),
+            };
 
-        Self { name, numbers }
+            if numbers.insert(value, ident).is_some() {
+                panic!("Duplicate discriminant value");
+            }
+            if value > max_number {
+                max_number = value;
+            }
+        }
+
+        Self {
+            name,
+            max_number,
+            numbers,
+        }
     }
 
+    /// Returns a token stream representing the maximum discriminant value of the enum
     fn max_discriminant(&self) -> TokenStream2 {
-        let max_discriminant = self.numbers.iter().map(|(_, num)| num).max().unwrap();
-        TokenStream2::from_str(&format!("{max_discriminant}")).unwrap()
+        TokenStream2::from_str(&format!("{}", self.max_number)).unwrap()
     }
 
+    /// Returns a vector of token streams representing the valid matches in the `pac::from_number` function
     fn valid_matches(&self) -> Vec<TokenStream2> {
         self.numbers
             .iter()
-            .map(|(ident, num)| {
+            .map(|(num, ident)| {
                 TokenStream2::from_str(&format!("{num} => Ok(Self::{ident})")).unwrap()
             })
             .collect()
     }
 
-    fn quote(&self, trait_name: &str, num_type: &str, const_name: &str) -> TokenStream2 {
+    /// Returns a vector of token streams representing the interrupt handler functions
+    fn interrupt_handlers(&self) -> Vec<TokenStream2> {
+        self.numbers
+            .values()
+            .map(|ident| {
+                quote! { fn #ident () }
+            })
+            .collect()
+    }
+
+    /// Returns a sorted vector of token streams representing all the elements of the interrupt array.
+    /// If an interrupt number is not present in the enum, the corresponding element is `None`.
+    /// Otherwise, it is `Some(<interrupt_handler>)`.
+    fn interrupt_array(&self) -> Vec<TokenStream2> {
+        let mut vectors = vec![];
+        for i in 0..=self.max_number {
+            if let Some(ident) = self.numbers.get(&i) {
+                vectors.push(quote! { Some(#ident) });
+            } else {
+                vectors.push(quote! { None });
+            }
+        }
+        vectors
+    }
+
+    /// Returns a vector of token streams representing the trait implementations for
+    /// the enum. If the trait is an interrupt trait, the implementation also includes
+    /// the interrupt handler functions and the interrupt array.
+    fn impl_trait(&self, attr: &PacTrait) -> Vec<TokenStream2> {
+        let mut res = vec![];
+
         let name = &self.name;
+
+        let trait_name = attr.trait_name();
+        let num_type = attr.num_type();
+        let const_name = attr.const_name();
+
         let max_discriminant = self.max_discriminant();
         let valid_matches = self.valid_matches();
 
-        let trait_name = TokenStream2::from_str(trait_name).unwrap();
-        let num_type = TokenStream2::from_str(num_type).unwrap();
-        let const_name = TokenStream2::from_str(const_name).unwrap();
-
-        quote! {
+        // Push the trait implementation
+        res.push(quote! {
             unsafe impl riscv_pac::#trait_name for #name {
                 const #const_name: #num_type = #max_discriminant;
 
@@ -88,7 +230,53 @@ impl PacNumberEnum {
                     }
                 }
             }
+        });
+
+        // Interrupt traits require additional code
+        if let PacTrait::Interrupt(interrupt_type) = attr {
+            let marker_trait_name = interrupt_type.marker_trait_name();
+
+            let isr_array_name = interrupt_type.isr_array_name();
+            let dispatch_fn_name = interrupt_type.dispatch_fn_name();
+
+            // Push the marker trait implementation
+            res.push(quote! { unsafe impl riscv_pac::#marker_trait_name for #name {} });
+
+            let interrupt_handlers = self.interrupt_handlers();
+            let interrupt_array = self.interrupt_array();
+
+            // Push the interrupt handler functions and the interrupt array
+            res.push(quote! {
+                extern "C" {
+                    #(#interrupt_handlers;)*
+                }
+
+                #[no_mangle]
+                pub static #isr_array_name: [Option<unsafe extern "C" fn()>; #max_discriminant + 1] = [
+                    #(#interrupt_array),*
+                ];
+
+                #[no_mangle]
+                unsafe extern "C" fn #dispatch_fn_name(code: usize) {
+                    extern "C" {
+                        fn DefaultHandler();
+                    }
+
+                    if code < #isr_array_name.len() {
+                        let h = &#isr_array_name[code];
+                        if let Some(handler) = h {
+                            handler();
+                        } else {
+                            DefaultHandler();
+                        }
+                    } else {
+                        DefaultHandler();
+                    }
+                }
+            });
         }
+
+        res
     }
 }
 
@@ -131,35 +319,14 @@ impl PacNumberEnum {
 #[proc_macro_attribute]
 pub fn pac_enum(attr: TokenStream, item: TokenStream) -> TokenStream {
     let input = parse_macro_input!(item as DeriveInput);
-    let pac_enum = PacNumberEnum::new(&input);
-
-    // attr should be unsafe ExceptionNumber, unsafe InterruptNumber, unsafe PriorityNumber, or unsafe HartIdNumber
-    // assert that attribute starts with the unsafe token. If not, raise a panic error
-    let attr = attr.to_string();
-    // split string into words and check if the first word is "unsafe"
-    let attrs = attr.split_whitespace().collect::<Vec<&str>>();
-    if attrs.is_empty() {
-        panic!("Attribute is empty. Expected: 'riscv_pac::pac_enum(unsafe <PacTraitToImplement>)'");
-    }
-    if attrs.len() > 2 {
-        panic!(
-            "Wrong attribute format. Expected: 'riscv_pac::pac_enum(unsafe <PacTraitToImplement>)'"
-        );
-    }
-    if attrs[0] != "unsafe" {
-        panic!("Attribute does not start with 'unsafe'. Expected: 'riscv_pac::pac_enum(unsafe <PacTraitToImplement>)'");
-    }
+    let pac_enum = PacEnumItem::new(&input);
+
+    let attr = parse_macro_input!(attr as PacTrait);
 
-    let trait_impl = match attrs[1] {
-        "ExceptionNumber" => pac_enum.quote("ExceptionNumber", "usize", "MAX_EXCEPTION_NUMBER"),
-        "InterruptNumber" => pac_enum.quote("InterruptNumber", "usize", "MAX_INTERRUPT_NUMBER"),
-        "PriorityNumber" => pac_enum.quote("PriorityNumber", "u8", "MAX_PRIORITY_NUMBER"),
-        "HartIdNumber" => pac_enum.quote("HartIdNumber", "u16", "MAX_HART_ID_NUMBER"),
-        _ => panic!("Unknown trait '{}'. Expected: 'ExceptionNumber', 'InterruptNumber', 'PriorityNumber', or 'HartIdNumber'", attrs[1]),
-    };
+    let trait_impl = pac_enum.impl_trait(&attr);
     quote! {
         #input
-        #trait_impl
+        #(#trait_impl)*
     }
     .into()
 }

riscv-pac/tests/ui/fail_empty_macro.stderr

@@ -1,7 +1,7 @@
-error: custom attribute panicked
+error: unexpected end of input, expected `unsafe`
  --> tests/ui/fail_empty_macro.rs:1:1
   |
 1 | #[riscv_pac::pac_enum]
   | ^^^^^^^^^^^^^^^^^^^^^^
   |
-  = help: message: Attribute is empty. Expected: 'riscv_pac::pac_enum(unsafe <PacTraitToImplement>)'
+  = note: this error originates in the attribute macro `riscv_pac::pac_enum` (in Nightly builds, run with -Z macro-backtrace for more info)

riscv-pac/tests/ui/fail_more_than_one_trait.stderr

@@ -1,7 +1,5 @@
-error: custom attribute panicked
- --> tests/ui/fail_more_than_one_trait.rs:1:1
+error: Unknown trait name. Expected: 'ExceptionNumber', 'CoreInterruptNumber', 'ExternalInterruptNumber', 'PriorityNumber', or 'HartIdNumber'
+ --> tests/ui/fail_more_than_one_trait.rs:1:30
   |
 1 | #[riscv_pac::pac_enum(unsafe InterruptNumber, unsafe PriorityNumber)]
-  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-  |
-  = help: message: Wrong attribute format. Expected: 'riscv_pac::pac_enum(unsafe <PacTraitToImplement>)'
+  |                              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

riscv-pac/tests/ui/fail_no_unsafe.stderr

@@ -1,7 +1,5 @@
-error: custom attribute panicked
- --> tests/ui/fail_no_unsafe.rs:1:1
+error: expected `unsafe`
+ --> tests/ui/fail_no_unsafe.rs:1:23
   |
 1 | #[riscv_pac::pac_enum(InterruptNumber)]
-  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-  |
-  = help: message: Attribute does not start with 'unsafe'. Expected: 'riscv_pac::pac_enum(unsafe <PacTraitToImplement>)'
+  |                       ^^^^^^^^^^^^^^^

riscv-pac/tests/ui/fail_unknown_trait.rs

@@ -1,4 +1,4 @@
-#[riscv_pac::pac_enum(unsafe CoreInterruptNumber)]
+#[riscv_pac::pac_enum(unsafe InterruptNumber)]
 #[derive(Clone, Copy, Debug, PartialEq)]
 enum Interrupt {
     I1 = 1,

riscv-pac/tests/ui/fail_unknown_trait.stderr

@@ -1,7 +1,5 @@
-error: custom attribute panicked
- --> tests/ui/fail_unknown_trait.rs:1:1
+error: Unknown trait name. Expected: 'ExceptionNumber', 'CoreInterruptNumber', 'ExternalInterruptNumber', 'PriorityNumber', or 'HartIdNumber'
+ --> tests/ui/fail_unknown_trait.rs:1:30
   |
-1 | #[riscv_pac::pac_enum(unsafe CoreInterruptNumber)]
-  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-  |
-  = help: message: Unknown trait 'CoreInterruptNumber'. Expected: 'ExceptionNumber', 'InterruptNumber', 'PriorityNumber', or 'HartIdNumber'
+1 | #[riscv_pac::pac_enum(unsafe InterruptNumber)]
+  |                              ^^^^^^^^^^^^^^^