1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70
//! "Hooks" provide a way for `tcx` functionality to be provided by some downstream crate without
//! everything in rustc having to depend on that crate. This is somewhat similar to queries, but
//! queries come with a lot of machinery for caching and incremental compilation, whereas hooks are
//! just plain function pointers without any of the query magic.
use crate::mir;
use crate::query::TyCtxtAt;
use crate::ty::{Ty, TyCtxt};
use rustc_span::DUMMY_SP;
macro_rules! declare_hooks {
($($(#[$attr:meta])*hook $name:ident($($arg:ident: $K:ty),*) -> $V:ty;)*) => {
impl<'tcx> TyCtxt<'tcx> {
$(
$(#[$attr])*
#[inline(always)]
#[must_use]
pub fn $name(self, $($arg: $K,)*) -> $V
{
self.at(DUMMY_SP).$name($($arg,)*)
}
)*
}
impl<'tcx> TyCtxtAt<'tcx> {
$(
$(#[$attr])*
#[inline(always)]
#[must_use]
#[instrument(level = "debug", skip(self), ret)]
pub fn $name(self, $($arg: $K,)*) -> $V
{
(self.tcx.hooks.$name)(self, $($arg,)*)
}
)*
}
pub struct Providers {
$(pub $name: for<'tcx> fn(
TyCtxtAt<'tcx>,
$($arg: $K,)*
) -> $V,)*
}
impl Default for Providers {
fn default() -> Self {
Providers {
$($name: |_, $($arg,)*| bug!(
"`tcx.{}{:?}` cannot be called as `{}` was never assigned to a provider function.\n",
stringify!($name),
($($arg,)*),
stringify!($name),
),)*
}
}
}
impl Copy for Providers {}
impl Clone for Providers {
fn clone(&self) -> Self { *self }
}
};
}
declare_hooks! {
/// Tries to destructure an `mir::Const` ADT or array into its variant index
/// and its field values. This should only be used for pretty printing.
hook try_destructure_mir_constant_for_diagnostics(val: mir::ConstValue<'tcx>, ty: Ty<'tcx>) -> Option<mir::DestructuredConstant<'tcx>>;
}