diff options
Diffstat (limited to 'compiler/rustc_monomorphize/src/partitioning/merging.rs')
-rw-r--r-- | compiler/rustc_monomorphize/src/partitioning/merging.rs | 111 |
1 files changed, 0 insertions, 111 deletions
diff --git a/compiler/rustc_monomorphize/src/partitioning/merging.rs b/compiler/rustc_monomorphize/src/partitioning/merging.rs deleted file mode 100644 index 5c524a184..000000000 --- a/compiler/rustc_monomorphize/src/partitioning/merging.rs +++ /dev/null @@ -1,111 +0,0 @@ -use std::cmp; - -use rustc_data_structures::fx::FxHashMap; -use rustc_hir::def_id::LOCAL_CRATE; -use rustc_middle::mir::mono::{CodegenUnit, CodegenUnitNameBuilder}; -use rustc_span::symbol::Symbol; - -use super::PartitioningCx; -use crate::partitioning::PreInliningPartitioning; - -pub fn merge_codegen_units<'tcx>( - cx: &PartitioningCx<'_, 'tcx>, - initial_partitioning: &mut PreInliningPartitioning<'tcx>, -) { - assert!(cx.target_cgu_count >= 1); - let codegen_units = &mut initial_partitioning.codegen_units; - - // Note that at this point in time the `codegen_units` here may not be in a - // deterministic order (but we know they're deterministically the same set). - // We want this merging to produce a deterministic ordering of codegen units - // from the input. - // - // Due to basically how we've implemented the merging below (merge the two - // smallest into each other) we're sure to start off with a deterministic - // order (sorted by name). This'll mean that if two cgus have the same size - // the stable sort below will keep everything nice and deterministic. - codegen_units.sort_by(|a, b| a.name().as_str().cmp(b.name().as_str())); - - // This map keeps track of what got merged into what. - let mut cgu_contents: FxHashMap<Symbol, Vec<Symbol>> = - codegen_units.iter().map(|cgu| (cgu.name(), vec![cgu.name()])).collect(); - - // Merge the two smallest codegen units until the target size is reached. - while codegen_units.len() > cx.target_cgu_count { - // Sort small cgus to the back - codegen_units.sort_by_cached_key(|cgu| cmp::Reverse(cgu.size_estimate())); - let mut smallest = codegen_units.pop().unwrap(); - let second_smallest = codegen_units.last_mut().unwrap(); - - // Move the mono-items from `smallest` to `second_smallest` - second_smallest.modify_size_estimate(smallest.size_estimate()); - for (k, v) in smallest.items_mut().drain() { - second_smallest.items_mut().insert(k, v); - } - - // Record that `second_smallest` now contains all the stuff that was in - // `smallest` before. - let mut consumed_cgu_names = cgu_contents.remove(&smallest.name()).unwrap(); - cgu_contents.get_mut(&second_smallest.name()).unwrap().append(&mut consumed_cgu_names); - - debug!( - "CodegenUnit {} merged into CodegenUnit {}", - smallest.name(), - second_smallest.name() - ); - } - - let cgu_name_builder = &mut CodegenUnitNameBuilder::new(cx.tcx); - - if cx.tcx.sess.opts.incremental.is_some() { - // If we are doing incremental compilation, we want CGU names to - // reflect the path of the source level module they correspond to. - // For CGUs that contain the code of multiple modules because of the - // merging done above, we use a concatenation of the names of - // all contained CGUs. - let new_cgu_names: FxHashMap<Symbol, String> = cgu_contents - .into_iter() - // This `filter` makes sure we only update the name of CGUs that - // were actually modified by merging. - .filter(|(_, cgu_contents)| cgu_contents.len() > 1) - .map(|(current_cgu_name, cgu_contents)| { - let mut cgu_contents: Vec<&str> = cgu_contents.iter().map(|s| s.as_str()).collect(); - - // Sort the names, so things are deterministic and easy to - // predict. - - // We are sorting primitive &strs here so we can use unstable sort - cgu_contents.sort_unstable(); - - (current_cgu_name, cgu_contents.join("--")) - }) - .collect(); - - for cgu in codegen_units.iter_mut() { - if let Some(new_cgu_name) = new_cgu_names.get(&cgu.name()) { - if cx.tcx.sess.opts.unstable_opts.human_readable_cgu_names { - cgu.set_name(Symbol::intern(&new_cgu_name)); - } else { - // If we don't require CGU names to be human-readable, we - // use a fixed length hash of the composite CGU name - // instead. - let new_cgu_name = CodegenUnit::mangle_name(&new_cgu_name); - cgu.set_name(Symbol::intern(&new_cgu_name)); - } - } - } - } else { - // If we are compiling non-incrementally we just generate simple CGU - // names containing an index. - for (index, cgu) in codegen_units.iter_mut().enumerate() { - cgu.set_name(numbered_codegen_unit_name(cgu_name_builder, index)); - } - } -} - -fn numbered_codegen_unit_name( - name_builder: &mut CodegenUnitNameBuilder<'_>, - index: usize, -) -> Symbol { - name_builder.build_cgu_name_no_mangle(LOCAL_CRATE, &["cgu"], Some(index)) -} |