bjoernager/rust
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Store item size estimate in MonoItemData.

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This means we call `MonoItem::size_estimate` (which involves a query)
less often: just once per mono item, and then once more per inline item
placement. After that we can reuse the stored value as necessary. This
means `CodegenUnit::compute_size_estimate` is cheaper.
This commit is contained in:
Nicholas Nethercote 2023-07-14 16:02:32 +10:00
parent b52f9eb6ca
commit edd1f3827e
2 changed files with 22 additions and 18 deletions
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11
compiler/rustc_middle/src/mir/mono.rs
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@ -243,6 +243,7 @@ pub struct CodegenUnit<'tcx> {
pub struct MonoItemData {
pub linkage: Linkage,
pub visibility: Visibility,
pub size_estimate: usize,
}
/// Specifies the linkage type for a `MonoItem`.
@ -327,16 +328,16 @@ impl<'tcx> CodegenUnit<'tcx> {
base_n::encode(hash, base_n::CASE_INSENSITIVE)
}
pub fn compute_size_estimate(&mut self, tcx: TyCtxt<'tcx>) {
// Estimate the size of a codegen unit as (approximately) the number of MIR
// statements it corresponds to.
self.size_estimate = self.items.keys().map(|mi| mi.size_estimate(tcx)).sum();
pub fn compute_size_estimate(&mut self) {
// The size of a codegen unit as the sum of the sizes of the items
// within it.
self.size_estimate = self.items.values().map(|data| data.size_estimate).sum();
}
#[inline]
/// Should only be called if [`compute_size_estimate`] has previously been called.
///
/// [`compute_size_estimate`]: Self::compute_size_estimate
#[inline]
pub fn size_estimate(&self) -> usize {
// Items are never zero-sized, so if we have items the estimate must be
// non-zero, unless we forgot to call `compute_size_estimate` first.