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firmware: use read_unaligned instead of a hack. NFC.

This commit is contained in:
whitequark 2017-10-02 03:38:31 +00:00
parent fd07c3f4d7
commit 2684aec4c6
1 changed files with 2 additions and 11 deletions
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13
artiq/firmware/ksupport/eh.rs
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@ -53,15 +53,6 @@ struct DwarfReader {
pub ptr: *const u8, pub ptr: *const u8,
} }
#[repr(C,packed)]
#[derive(Clone, Copy)]
struct Unaligned<T>(T);
// This contortion is required due to https://github.com/rust-lang/rust/issues/27060.
impl<T> Unaligned<T> {
fn get(self) -> T { self.0 }
}
impl DwarfReader { impl DwarfReader {
fn new(ptr: *const u8) -> DwarfReader { fn new(ptr: *const u8) -> DwarfReader {
DwarfReader { ptr: ptr } DwarfReader { ptr: ptr }
@ -72,9 +63,9 @@ impl DwarfReader {
// alignment requirements. By wrapping data in a "packed" struct, we are // alignment requirements. By wrapping data in a "packed" struct, we are
// telling the backend to generate "misalignment-safe" code. // telling the backend to generate "misalignment-safe" code.
unsafe fn read<T: Copy>(&mut self) -> T { unsafe fn read<T: Copy>(&mut self) -> T {
let result = *(self.ptr as *const Unaligned<T>); let result = ptr::read_unaligned(self.ptr as *const T);
self.ptr = self.ptr.offset(mem::size_of::<T>() as isize); self.ptr = self.ptr.offset(mem::size_of::<T>() as isize);
result.get() result
} }
// ULEB128 and SLEB128 encodings are defined in Section 7.6 - "Variable // ULEB128 and SLEB128 encodings are defined in Section 7.6 - "Variable