turn macros into attributes

13 files changed, 517 insertions, 281 deletions

diff --git a/cortex-m-rt/.gitignore b/cortex-m-rt/.gitignore
index c71d6db..d8748d6 100644
--- a/cortex-m-rt/.gitignore
+++ b/cortex-m-rt/.gitignore
@@ -1,4 +1,5 @@
 **/*.rs.bk
+.#*
 Cargo.lock
 bin/*.after
 bin/*.before
diff --git a/cortex-m-rt/Cargo.toml b/cortex-m-rt/Cargo.toml
index 0dfbaf7..016cdc9 100644
--- a/cortex-m-rt/Cargo.toml
+++ b/cortex-m-rt/Cargo.toml
@@ -12,6 +12,7 @@ version = "0.5.3"
 
 [dependencies]
 r0 = "0.2.1"
+cortex-m-rt-macros = { path = "macros", version = "0.1.0" }
 
 [dev-dependencies]
 panic-semihosting = "0.3.0"
diff --git a/cortex-m-rt/ci/script.sh b/cortex-m-rt/ci/script.sh
index 7d1cc67..242a546 100644
--- a/cortex-m-rt/ci/script.sh
+++ b/cortex-m-rt/ci/script.sh
@@ -5,6 +5,8 @@ main() {
 
     cargo check --target $TARGET --features device
 
+    ( cd macros && cargo check && cargo test )
+
     local examples=(
         alignment
         minimal
diff --git a/cortex-m-rt/examples/alignment.rs b/cortex-m-rt/examples/alignment.rs
index 5635851..25d755d 100644
--- a/cortex-m-rt/examples/alignment.rs
+++ b/cortex-m-rt/examples/alignment.rs
@@ -4,13 +4,12 @@
 #![no_main]
 #![no_std]
 
-#[macro_use(entry)]
 extern crate cortex_m_rt as rt;
 extern crate panic_abort;
 
 use core::ptr;
 
-entry!(main);
+use rt::entry;
 
 static mut BSS1: u16 = 0;
 static mut BSS2: u8 = 0;
@@ -19,6 +18,7 @@ static mut DATA2: u16 = 1;
 static RODATA1: &[u8; 3] = b"012";
 static RODATA2: &[u8; 2] = b"34";
 
+#[entry]
 fn main() -> ! {
     unsafe {
         let _bss1 = ptr::read_volatile(&BSS1);
diff --git a/cortex-m-rt/examples/data_overflow.rs b/cortex-m-rt/examples/data_overflow.rs
index 396f1c8..ceec18b 100644
--- a/cortex-m-rt/examples/data_overflow.rs
+++ b/cortex-m-rt/examples/data_overflow.rs
@@ -5,13 +5,12 @@
 #![no_main]
 #![no_std]
 
-#[macro_use(entry)]
 extern crate cortex_m_rt as rt;
 extern crate panic_abort;
 
 use core::ptr;
 
-entry!(main);
+use rt::entry;
 
 // This large static array uses most of .rodata
 static RODATA: [u8; 48*1024] = [1u8; 48*1024];
@@ -20,6 +19,7 @@ static RODATA: [u8; 48*1024] = [1u8; 48*1024];
 // without also overflowing RAM.
 static mut DATA: [u8; 16*1024] = [1u8; 16*1024];
 
+#[entry]
 fn main() -> ! {
     unsafe {
         let _bigdata = ptr::read_volatile(&RODATA as *const u8);
diff --git a/cortex-m-rt/examples/device.rs b/cortex-m-rt/examples/device.rs
index 4395db2..950a564 100644
--- a/cortex-m-rt/examples/device.rs
+++ b/cortex-m-rt/examples/device.rs
@@ -5,13 +5,12 @@
 #![no_main]
 #![no_std]
 
-#[macro_use(entry)]
 extern crate cortex_m_rt as rt;
 extern crate panic_semihosting;
 
-// the program entry point
-entry!(main);
+use rt::entry;
 
+#[entry]
 fn main() -> ! {
     loop {}
 }
diff --git a/cortex-m-rt/examples/minimal.rs b/cortex-m-rt/examples/minimal.rs
index a036046..6f60180 100644
--- a/cortex-m-rt/examples/minimal.rs
+++ b/cortex-m-rt/examples/minimal.rs
@@ -5,13 +5,13 @@
 #![no_main]
 #![no_std]
 
-#[macro_use(entry)]
 extern crate cortex_m_rt as rt;
 extern crate panic_semihosting;
 
-// the program entry point
-entry!(main);
+use rt::entry;
 
+// the program entry point
+#[entry]
 fn main() -> ! {
     loop {}
 }
diff --git a/cortex-m-rt/examples/override-exception.rs b/cortex-m-rt/examples/override-exception.rs
index 2f100a2..dca31e6 100644
--- a/cortex-m-rt/examples/override-exception.rs
+++ b/cortex-m-rt/examples/override-exception.rs
@@ -6,28 +6,23 @@
 #![no_std]
 
 extern crate cortex_m;
-#[macro_use(entry, exception)]
 extern crate cortex_m_rt as rt;
 extern crate panic_semihosting;
 
 use cortex_m::asm;
-use rt::ExceptionFrame;
-
-// the program entry point
-entry!(main);
+use rt::{entry, exception, ExceptionFrame};
 
+#[entry]
 fn main() -> ! {
     loop {}
 }
 
-exception!(*, default_handler);
-
+#[exception(DefaultHandler)]
 fn default_handler(_irqn: i16) {
     asm::bkpt();
 }
 
-exception!(HardFault, hard_fault);
-
+#[exception(HardFault)]
 fn hard_fault(_ef: &ExceptionFrame) -> ! {
     asm::bkpt();
 
diff --git a/cortex-m-rt/examples/pre_init.rs b/cortex-m-rt/examples/pre_init.rs
index 7258936..00e2f2c 100644
--- a/cortex-m-rt/examples/pre_init.rs
+++ b/cortex-m-rt/examples/pre_init.rs
@@ -4,19 +4,17 @@
 #![no_main]
 #![no_std]
 
-#[macro_use(entry, pre_init)]
 extern crate cortex_m_rt as rt;
 extern crate panic_semihosting;
 
-pre_init!(disable_watchdog);
+use rt::{entry, pre_init};
 
+#[pre_init]
 unsafe fn disable_watchdog() {
     // Do what you need to disable the watchdog.
 }
 
-// the program entry point
-entry!(main);
-
+#[entry]
 fn main() -> ! {
     loop {}
 }
diff --git a/cortex-m-rt/examples/state.rs b/cortex-m-rt/examples/state.rs
index dbacdaf..72ca194 100644
--- a/cortex-m-rt/examples/state.rs
+++ b/cortex-m-rt/examples/state.rs
@@ -5,20 +5,18 @@
 #![no_main]
 #![no_std]
 
-#[macro_use(entry, exception)]
 extern crate cortex_m_rt as rt;
 extern crate panic_semihosting;
 
-// the program entry point
-entry!(main);
+use rt::{entry, exception};
 
+#[entry]
 fn main() -> ! {
     loop {}
 }
 
 // exception handler with state
-exception!(SysTick, sys_tick, state: u32 = 0);
-
-fn sys_tick(state: &mut u32) {
-    *state += 1;
+#[exception(SysTick, static STATE: u32 = 0)]
+fn sys_tick() {
+    *STATE += 1;
 }
diff --git a/cortex-m-rt/macros/Cargo.toml b/cortex-m-rt/macros/Cargo.toml
new file mode 100644
index 0000000..85e8cd1
--- /dev/null
+++ b/cortex-m-rt/macros/Cargo.toml
@@ -0,0 +1,17 @@
+[package]
+name = "cortex-m-rt-macros"
+version = "0.1.0"
+authors = ["Jorge Aparicio <jorge@japaric.io>"]
+
+[lib]
+proc-macro = true
+
+[dependencies]
+quote = "0.6.6"
+
+[dependencies.syn]
+features = ["extra-traits", "full"]
+version = "0.14.8"
+
+[dev-dependencies]
+cortex-m-rt = { path = ".." }
diff --git a/cortex-m-rt/macros/src/lib.rs b/cortex-m-rt/macros/src/lib.rs
new file mode 100644
index 0000000..3aa494d
--- /dev/null
+++ b/cortex-m-rt/macros/src/lib.rs
@@ -0,0 +1,462 @@
+#![deny(warnings)]
+
+extern crate proc_macro;
+#[macro_use]
+extern crate quote;
+#[macro_use]
+extern crate syn;
+
+use syn::synom::Synom;
+use syn::token::{Colon, Comma, Eq, Static};
+use syn::{Expr, FnArg, Ident, ItemFn, ReturnType, Type, Visibility};
+
+use proc_macro::TokenStream;
+
+/// Attribute to declare the entry point of the program
+///
+/// **NOTE** This macro must be invoked once and must be invoked from an accessible module, ideally
+/// from the root of the crate.
+///
+/// The specified function will be called by the reset handler *after* RAM has been initialized. In
+/// 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)
+///
+/// # Examples
+///
+/// ``` no_run
+/// # #![no_main]
+/// # use cortex_m_rt_macros::entry;
+/// #[entry]
+/// fn main() -> ! {
+///     loop {
+///         /* .. */
+///     }
+/// }
+/// ```
+#[proc_macro_attribute]
+pub fn entry(args: TokenStream, input: TokenStream) -> TokenStream {
+    let f: ItemFn = syn::parse(input).expect("`#[entry]` must be applied to a function");
+
+    // check the function signature
+    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()
+            && f.decl.generics.where_clause.is_none()
+            && f.decl.variadic.is_none()
+            && match f.decl.output {
+                ReturnType::Default => false,
+                ReturnType::Type(_, ref ty) => match **ty {
+                    Type::Never(_) => true,
+                    _ => false,
+                },
+            },
+        "`#[entry]` function must have signature `fn() -> !`"
+    );
+
+    assert_eq!(
+        args.to_string(),
+        "",
+        "`entry` attribute must have no arguments"
+    );
+
+    // XXX should we blacklist other attributes?
+    let attrs = f.attrs;
+    let ident = f.ident;
+    let block = f.block;
+
+    quote!(
+        #[export_name = "main"]
+        #(#attrs)*
+        pub fn #ident() -> ! #block
+    ).into()
+}
+
+struct ExceptionArgs {
+    first: Ident,
+    second: Option<State>,
+}
+
+impl Synom for ExceptionArgs {
+    named!(parse -> Self, do_parse!(
+        first: syn!(Ident) >>
+            second: option!(syn!(State)) >> (
+                ExceptionArgs { first, second }
+            )
+    ));
+}
+
+struct State {
+    _comma: Comma,
+    _static: Static,
+    ident: Ident,
+    _colon: Colon,
+    ty: Type,
+    _eq: Eq,
+    expr: Expr,
+}
+
+impl Synom for State {
+    named!(parse -> Self, do_parse!(
+        _comma: punct!(,) >>
+            _static: syn!(Static) >>
+            ident: syn!(Ident) >>
+            _colon: punct!(:) >>
+            ty: syn!(Type) >>
+            _eq: punct!(=) >>
+            expr: syn!(Expr) >> (
+                State { _comma, _static, ident, _colon, ty, _eq, expr }
+            )
+    ));
+}
+
+/// Attribute to declare an exception handler
+///
+/// **NOTE** This macro must be invoked from an accessible module, ideally from the root of the
+/// crate.
+///
+/// # Syntax
+///
+/// ```
+/// # use cortex_m_rt_macros::exception;
+/// #[exception(SysTick, static COUNT: u32 = 0)]
+/// fn handler() {
+///     // ..
+/// }
+///
+/// # fn main() {}
+/// ```
+///
+/// where the first argument can be one of:
+///
+/// - `DefaultHandler`
+/// - `NonMaskableInt`
+/// - `HardFault`
+/// - `MemoryManagement` (a)
+/// - `BusFault` (a)
+/// - `UsageFault` (a)
+/// - `SecureFault` (b)
+/// - `SVCall`
+/// - `DebugMonitor` (a)
+/// - `PendSV`
+/// - `SysTick`
+///
+/// and the second is optional.
+///
+/// (a) Not available on Cortex-M0 variants (`thumbv6m-none-eabi`)
+///
+/// (b) Only available on ARMv8-M
+///
+/// # Usage
+///
+/// `#[exception(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.
+///
+/// `#[exception(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).
+///
+/// `#[exception(Name)]` overrides the default handler for the exception with the given `Name`.
+///
+/// # Examples
+///
+/// - Setting the `HardFault` handler
+///
+/// ```
+/// # extern crate cortex_m_rt;
+/// # extern crate cortex_m_rt_macros;
+/// # use cortex_m_rt_macros::exception;
+/// #[exception(HardFault)]
+/// fn hard_fault(ef: &cortex_m_rt::ExceptionFrame) -> ! {
+///     // prints the exception frame as a panic message
+///     panic!("{:#?}", ef);
+/// }
+///
+/// # fn main() {}
+/// ```
+///
+/// - Setting the default handler
+///
+/// ```
+/// # use cortex_m_rt_macros::exception;
+/// #[exception(DefaultHandler)]
+/// fn default_handler(irqn: i16) {
+///     println!("IRQn = {}", irqn);
+/// }
+///
+/// # fn main() {}
+/// ```
+///
+/// - Overriding the `SysTick` handler
+///
+/// ```
+/// extern crate cortex_m_rt as rt;
+///
+/// use rt::exception;
+///
+/// #[exception(SysTick, static COUNT: i32 = 0)]
+/// fn sys_tick() {
+///     *COUNT += 1;
+///
+///     println!("{}", COUNT);
+/// }
+///
+/// # fn main() {}
+/// ```
+#[proc_macro_attribute]
+pub fn exception(args: TokenStream, input: TokenStream) -> TokenStream {
+    let f: ItemFn = syn::parse(input).expect("`#[exception]` must be applied to a function");
+    let args: ExceptionArgs = syn::parse(args).expect(
+        "`exception` attribute expects the exception name as its argument. \
+         e.g. `#[exception(HardFault)]`",
+    );
+    let name = args.first;
+    let name_s = name.to_string();
+
+    enum Exception {
+        DefaultHandler,
+        HardFault,
+        Other,
+    }
+
+    // first validation of the exception name
+    let exn = match &*name_s {
+        "DefaultHandler" => Exception::DefaultHandler,
+        "HardFault" => Exception::HardFault,
+        // NOTE that at this point we don't check if the exception is available on the target (e.g.
+        // MemoryManagement is not available on Cortex-M0)
+        "NonMaskableInt" | "MemoryManagement" | "BusFault" | "UsageFault" | "SecureFault"
+        | "SVCall" | "DebugMonitor" | "PendSV" | "SysTick" => Exception::Other,
+        _ => panic!("{} is not a valid exception name", name_s),
+    };
+
+    // XXX should we blacklist other attributes?
+    let attrs = f.attrs;
+    let ident = f.ident;
+    let block = f.block;
+    let stmts = &block.stmts;
+
+    match exn {
+        Exception::DefaultHandler => {
+            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()
+                    && f.decl.generics.where_clause.is_none()
+                    && f.decl.variadic.is_none()
+                    && match f.decl.output {
+                        ReturnType::Default => true,
+                        ReturnType::Type(_, ref ty) => match **ty {
+                            Type::Tuple(ref tuple) => tuple.elems.is_empty(),
+                            _ => false,
+                        },
+                    },
+                "`#[exception(DefaultHandler)]` function must have signature `fn(i16)`"
+            );
+
+            assert!(
+                args.second.is_none(),
+                "`#[exception(DefaultHandler)]` takes no additional arguments"
+            );
+
+            let arg = match f.decl.inputs[0] {
+                FnArg::Captured(ref arg) => arg,
+                _ => unreachable!(),
+            };
+
+            quote!(
+                #[export_name = #name_s]
+                #(#attrs)*
+                pub fn #ident() {
+                    extern crate core;
+
+                    const SCB_ICSR: *const u32 = 0xE000_ED04 as *const u32;
+
+                    let #arg = unsafe { core::ptr::read(SCB_ICSR) as u8 as i16 - 16 };
+
+                    #(#stmts)*
+                }
+            ).into()
+        }
+        Exception::HardFault => {
+            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] {
+                        FnArg::Captured(ref arg) => match arg.ty {
+                            Type::Reference(ref r) => {
+                                r.lifetime.is_none() && r.mutability.is_none()
+                            }
+                            _ => false,
+                        },
+                        _ => false,
+                    }
+                    && f.decl.generics.params.is_empty()
+                    && f.decl.generics.where_clause.is_none()
+                    && f.decl.variadic.is_none()
+                    && match f.decl.output {
+                        ReturnType::Default => false,
+                        ReturnType::Type(_, ref ty) => match **ty {
+                            Type::Never(_) => true,
+                            _ => false,
+                        },
+                    },
+                "`#[exception(HardFault)]` function must have signature `fn(&ExceptionFrame) -> !`"
+            );
+
+            assert!(
+                args.second.is_none(),
+                "`#[exception(HardFault)]` takes no additional arguments"
+            );
+
+            let arg = match f.decl.inputs[0] {
+                FnArg::Captured(ref arg) => arg,
+                _ => unreachable!(),
+            };
+
+            let pat = &arg.pat;
+
+            quote!(
+                #[export_name = "UserHardFault"]
+                #(#attrs)*
+                pub unsafe extern "C" fn #ident(#arg) -> ! {
+                    extern crate cortex_m_rt;
+
+                    // further type check of the input argument
+                    let #pat: &cortex_m_rt::ExceptionFrame = #pat;
+
+                    #(#stmts)*
+                }
+            ).into()
+        }
+        Exception::Other => {
+            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()
+                    && f.decl.generics.where_clause.is_none()
+                    && f.decl.variadic.is_none()
+                    && match f.decl.output {
+                        ReturnType::Default => true,
+                        ReturnType::Type(_, ref ty) => match **ty {
+                            Type::Tuple(ref tuple) => tuple.elems.is_empty(),
+                            _ => false,
+                        },
+                    },
+                "`#[exception]` functions must have signature `fn()`"
+            );
+
+            if let Some(second) = args.second {
+                let ty = second.ty;
+                let expr = second.expr;
+                let state = second.ident;
+
+                quote!(
+                    #[export_name = #name_s]
+                    #(#attrs)*
+                    pub fn #ident() {
+                        extern crate cortex_m_rt;
+
+                        cortex_m_rt::Exception::#name;
+
+                        static mut __STATE__: #ty = #expr;
+
+                        #[allow(non_snake_case)]
+                        let #state: &mut #ty = unsafe { &mut __STATE__ };
+
+                        #(#stmts)*
+                    }
+                ).into()
+            } else {
+                quote!(
+                    #[export_name = #name_s]
+                    #(#attrs)*
+                    pub fn #ident() {
+                        extern crate cortex_m_rt;
+
+                        cortex_m_rt::Exception::#name;
+
+                        #(#stmts)*
+                    }
+                ).into()
+            }
+        }
+    }
+}
+
+/// Attribute to mark which function will be called at the beginning of the reset handler.
+///
+/// The function must have the signature of `unsafe fn()`.
+///
+/// The function passed will be called before static variables are initialized. Any access of static
+/// variables will result in undefined behavior.
+///
+/// # Examples
+///
+/// ```
+/// # use cortex_m_rt_macros::pre_init;
+/// #[pre_init]
+/// unsafe fn before_main() {
+///     // do something here
+/// }
+///
+/// # fn main() {}
+/// ```
+#[proc_macro_attribute]
+pub fn pre_init(args: TokenStream, input: TokenStream) -> TokenStream {
+    let f: ItemFn = syn::parse(input).expect("`#[pre_init]` must be applied to a function");
+
+    // check the function signature
+    assert!(
+        f.constness.is_none()
+            && f.vis == Visibility::Inherited
+            && f.unsafety.is_some()
+            && f.abi.is_none()
+            && f.decl.inputs.is_empty()
+            && f.decl.generics.params.is_empty()
+            && f.decl.generics.where_clause.is_none()
+            && f.decl.variadic.is_none()
+            && match f.decl.output {
+                ReturnType::Default => true,
+                ReturnType::Type(_, ref ty) => match **ty {
+                    Type::Tuple(ref tuple) => tuple.elems.is_empty(),
+                    _ => false,
+                },
+            },
+        "`#[pre_init]` function must have signature `unsafe fn()`"
+    );
+
+    assert_eq!(
+        args.to_string(),
+        "",
+        "`pre_init` attribute must have no arguments"
+    );
+
+    // XXX should we blacklist other attributes?
+    let attrs = f.attrs;
+    let ident = f.ident;
+    let block = f.block;
+
+    quote!(
+        #[export_name = "__pre_init"]
+        #(#attrs)*
+        pub unsafe fn #ident() #block
+    ).into()
+}
diff --git a/cortex-m-rt/src/lib.rs b/cortex-m-rt/src/lib.rs
index 10f60f6..526b28b 100644
--- a/cortex-m-rt/src/lib.rs
+++ b/cortex-m-rt/src/lib.rs
@@ -94,18 +94,16 @@
 //! #![no_main]
 //! #![no_std]
 //!
-//! #[macro_use(entry, exception)]
 //! extern crate cortex_m_rt as rt;
 //!
 //! // makes `panic!` print messages to the host stderr using semihosting
 //! extern crate panic_semihosting;
 //!
-//! use rt::ExceptionFrame;
+//! use rt::entry;
 //!
 //! // use `main` as the entry point of this application
-//! entry!(main);
-//!
 //! // `main` is not allowed to return
+//! #[entry]
 //! fn main() -> ! {
 //!     // initialization
 //!
@@ -113,20 +111,6 @@
 //!         // application logic
 //!     }
 //! }
-//!
-//! // define the hard fault handler
-//! exception!(HardFault, hard_fault);
-//!
-//! fn hard_fault(ef: &ExceptionFrame) -> ! {
-//!     panic!("{:#?}", ef);
-//! }
-//!
-//! // define the default exception handler
-//! exception!(*, default_handler);
-//!
-//! fn default_handler(irqn: i16) {
-//!     panic!("unhandled exception (IRQn={})", irqn);
-//! }
 //! ```
 //!
 //! To actually build this program you need to place a `memory.x` linker script somewhere the linker
@@ -397,11 +381,14 @@
 #![deny(warnings)]
 #![no_std]
 
+extern crate cortex_m_rt_macros as macros;
 extern crate r0;
 
 use core::fmt;
 use core::sync::atomic::{self, Ordering};
 
+pub use macros::{entry, exception, pre_init};
+
 /// Registers stacked (pushed into the stack) during an exception
 #[derive(Clone, Copy)]
 #[repr(C)]
@@ -474,8 +461,6 @@ pub static __RESET_VECTOR: unsafe extern "C" fn() -> ! = Reset;
 #[no_mangle]
 pub unsafe extern "C" fn Reset() -> ! {
     extern "C" {
-        // This symbol will be provided by the user via the `entry!` macro
-        fn main() -> !;
 
         // These symbols come from `link.x`
         static mut __sbss: u32;
@@ -485,11 +470,17 @@ pub unsafe extern "C" fn Reset() -> ! {
         static mut __edata: u32;
         static __sidata: u32;
 
+    }
+
+    extern "Rust" {
+        // This symbol will be provided by the user via `#[entry]`
+        fn main() -> !;
+
+        // This symbol will be provided by the user via `#[pre_init]`
         fn __pre_init();
     }
 
-    let pre_init: unsafe extern "C" fn() = __pre_init;
-    pre_init();
+    __pre_init();
 
     // Initialize RAM
     r0::zero_bss(&mut __sbss, &mut __ebss);
@@ -551,31 +542,6 @@ pub unsafe extern "C" fn DefaultHandler_() -> ! {
 #[no_mangle]
 pub unsafe extern "C" fn DefaultPreInit() {}
 
-/// Macro to define the entry point of the program
-///
-/// **NOTE** This macro must be invoked once and must be invoked from an accessible module, ideally
-/// from the root of the crate.
-///
-/// Usage: `entry!(path::to::entry::point)`
-///
-/// The specified function will be called by the reset handler *after* RAM has been initialized. In
-/// the case of the `thumbv7em-none-eabihf` target the FPU will also be enabled before the function
-/// is called.
-///
-/// The signature of the specified function must be `fn() -> !` (never ending function)
-#[macro_export]
-macro_rules! entry {
-    ($path:expr) => {
-        #[export_name = "main"]
-        pub extern "C" fn __impl_main() -> ! {
-            // validate the signature of the program entry point
-            let f: fn() -> ! = $path;
-
-            f()
-        }
-    };
-}
-
 /* Exceptions */
 #[doc(hidden)]
 pub enum Exception {
@@ -721,206 +687,3 @@ pub static __INTERRUPTS: [unsafe extern "C" fn(); 32] = [{
 
     DefaultHandler
 }; 32];
-
-/// Macro to set or override a processor core exception handler
-///
-/// **NOTE** This macro must be invoked from an accessible module, ideally from the root of the
-/// crate.
-///
-/// # Syntax
-///
-/// ``` ignore
-/// exception!(
-///     // Name of the exception
-///     $Name:ident,
-///
-///     // Path to the exception handler (a function)
-///     $handler:expr,
-///
-///     // Optional, state preserved across invocations of the handler
-///     state: $State:ty = $initial_state:expr,
-/// );
-/// ```
-///
-/// where `$Name` can be one of:
-///
-/// - `*`
-/// - `NonMaskableInt`
-/// - `HardFault`
-/// - `MemoryManagement` (a)
-/// - `BusFault` (a)
-/// - `UsageFault` (a)
-/// - `SecureFault` (b)
-/// - `SVCall`
-/// - `DebugMonitor` (a)
-/// - `PendSV`
-/// - `SysTick`
-///
-/// (a) Not available on Cortex-M0 variants (`thumbv6m-none-eabi`)
-///
-/// (b) Only available on ARMv8-M
-///
-/// # Usage
-///
-/// `exception!(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. It's mandatory to set the `HardFault` handler somewhere in the dependency graph of an
-/// application.
-///
-/// `exception!(*, ..)` 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 (cf. 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). It's mandatory to set the default handler somewhere
-/// in the dependency graph of an application.
-///
-/// `exception!($Exception, ..)` overrides the default handler for `$Exception`. All exceptions,
-/// except for `HardFault`, can be assigned some `$State`.
-///
-/// # Examples
-///
-/// - Setting the `HardFault` handler
-///
-/// ```
-/// #[macro_use(exception)]
-/// extern crate cortex_m_rt as rt;
-///
-/// use rt::ExceptionFrame;
-///
-/// exception!(HardFault, hard_fault);
-///
-/// fn hard_fault(ef: &ExceptionFrame) -> ! {
-///     // prints the exception frame as a panic message
-///     panic!("{:#?}", ef);
-/// }
-///
-/// # fn main() {}
-/// ```
-///
-/// - Setting the default handler
-///
-/// ```
-/// #[macro_use(exception)]
-/// extern crate cortex_m_rt as rt;
-///
-/// exception!(*, default_handler);
-///
-/// fn default_handler(irqn: i16) {
-///     println!("IRQn = {}", irqn);
-/// }
-///
-/// # fn main() {}
-/// ```
-///
-/// - Overriding the `SysTick` handler
-///
-/// ```
-/// #[macro_use(exception)]
-/// extern crate cortex_m_rt as rt;
-///
-/// exception!(SysTick, sys_tick, state: u32 = 0);
-///
-/// fn sys_tick(count: &mut u32) {
-///     println!("count = {}", *count);
-///
-///     *count += 1;
-/// }
-///
-/// # fn main() {}
-/// ```
-#[macro_export]
-macro_rules! exception {
-    (* , $handler:expr) => {
-        #[allow(unsafe_code)]
-        #[deny(private_no_mangle_fns)] // raise an error if this item is not accessible
-        #[no_mangle]
-        pub unsafe extern "C" fn DefaultHandler() {
-            extern crate core;
-
-            // validate the signature of the user provided handler
-            let f: fn(i16) = $handler;
-
-            const SCB_ICSR: *const u32 = 0xE000_ED04 as *const u32;
-
-            // NOTE not volatile so the compiler can opt the load operation away if the value is
-            // unused
-            f(core::ptr::read(SCB_ICSR) as u8 as i16 - 16)
-        }
-    };
-
-    (HardFault, $handler:expr) => {
-        #[allow(unsafe_code)]
-        #[deny(private_no_mangle_fns)] // raise an error if this item is not accessible
-        #[no_mangle]
-        pub unsafe extern "C" fn UserHardFault(ef: &$crate::ExceptionFrame) {
-            // validate the signature of the user provided handler
-            let f: fn(&$crate::ExceptionFrame) -> ! = $handler;
-
-            f(ef)
-        }
-    };
-
-    ($Name:ident, $handler:expr,state: $State:ty = $initial_state:expr) => {
-        #[allow(unsafe_code)]
-        #[deny(private_no_mangle_fns)] // raise an error if this item is not accessible
-        #[no_mangle]
-        pub unsafe extern "C" fn $Name() {
-            static mut STATE: $State = $initial_state;
-
-            // check that this exception exists
-            let _ = $crate::Exception::$Name;
-
-            // validate the signature of the user provided handler
-            let f: fn(&mut $State) = $handler;
-
-            f(&mut STATE)
-        }
-    };
-
-    ($Name:ident, $handler:expr) => {
-        #[allow(unsafe_code)]
-        #[deny(private_no_mangle_fns)] // raise an error if this item is not accessible
-        #[no_mangle]
-        pub unsafe extern "C" fn $Name() {
-            // check that this exception exists
-            let _ = $crate::Exception::$Name;
-
-            // validate the signature of the user provided handler
-            let f: fn() = $handler;
-
-            f()
-        }
-    };
-}
-
-/// Macro to set the function to be called at the beginning of the reset handler.
-///
-/// The function must have the signature of `unsafe fn()`.
-///
-/// The function passed will be called before static variables are initialized. Any access of static
-/// variables will result in undefined behavior.
-///
-/// # Examples
-///
-/// ``` ignore
-/// pre_init!(foo::bar);
-///
-/// mod foo {
-///     pub unsafe fn bar() {
-///         // do something here
-///     }
-/// }
-/// ```
-#[macro_export]
-macro_rules! pre_init {
-    ($handler:path) => {
-        #[allow(unsafe_code)]
-        #[deny(private_no_mangle_fns)] // raise an error if this item is not accessible
-        #[no_mangle]
-        pub unsafe extern "C" fn __pre_init() {
-            // validate user handler
-            let f: unsafe fn() = $handler;
-            f();
-        }
-    };
-}