Print CGU reuse statistics in -Zprint-mono-items
#144899
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Some changes occurred in compiler/rustc_codegen_ssa |
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Rerolling a codegen reviewer for vibes on the approach; even though this is an perma-unstable flag. |
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Will be nice to name it |
bjorn3
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Aug 4, 2025
| @@ -735,6 +735,11 @@ pub fn codegen_crate<B: ExtraBackendMethods>( | |||
| crate::assert_module_sources::assert_module_sources(tcx, &|cgu_reuse_tracker| { | |||
| for (i, cgu) in codegen_units.iter().enumerate() { | |||
| let cgu_reuse = cgu_reuse[i]; | |||
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| if tcx.sess.opts.unstable_opts.print_mono_items { | |||
| println!("CGU_REUSE {} {cgu_reuse}", cgu.name()); | |||
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Maybe do this inside the cgu_reuse_tracker instead? The current changes in this PR don't apply to cg_clif.
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Good point, moved it to assert_module_sources.
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@bors r+ rollup |
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Print CGU reuse statistics in `-Zprint-mono-items` I'm trying to expose more information about incremental profiling from rustc (https://rust-lang.zulipchat.com/#narrow/channel/131828-t-compiler/topic/Profiling.2Fanalysis.20of.20incremental.20builds/with/531383501). One of the things that would be quite useful to expose is the CGU reuse state, so that when you do a rebuild, you can see all the CGUs (and all the functions) that had to be recompiled. Currently, we have (AFAIK) two ways of outputting monomorphization statistics: 1) `-Zdump-mono-stats` outputs statistics about number of instantiations and expected compilation cost of individual functions in the local crate being compiled. It can be outputted either as Markdown or JSON. 2) `-Zprint-mono-items` outputs a pair (item, CGU) for each monomorphized item. I was thinking about recording CGU statistics in the self-profile output, but I realized that as a simpler step, we could just add CGU reuse data to `-Zprint-mono-items`, as an additional output. That is what this PR does.
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Rollup of 19 pull requests Successful merges: - #144400 (`tests/ui/issues/`: The Issues Strike Back [3/N]) - #144764 ([codegen] assume the tag, not the relative discriminant) - #144807 (Streamline config in bootstrap) - #144899 (Print CGU reuse statistics in `-Zprint-mono-items`) - #144909 (Add new `test::print_merged_doctests_times` used by rustdoc to display more detailed time information) - #144912 (Resolver: introduce a conditionally mutable Resolver for (non-)speculative resolution.) - #144914 (Add support for `ty::Instance` path shortening in diagnostics) - #144931 ([win][arm64ec] Fix msvc-wholearchive for Arm64EC) - #144999 (coverage: Remove all unstable support for MC/DC instrumentation) - #145009 (A couple small changes for rust-analyzer next-solver work) - #145030 (GVN: Do not flatten derefs with ProjectionElem::Index. ) - #145042 (stdarch subtree update) - #145047 (move `type_check` out of `compute_regions`) - #145051 (Prevent name collisions with internal implementation details) - #145053 (Add a lot of NLL `known-bug` tests) - #145055 (Move metadata symbol export from exported_non_generic_symbols to exported_symbols) - #145057 (Clean up some resolved test regressions of const trait removals in std) - #145068 (Readd myself to review queue) - #145070 (Add minimal `armv7a-vex-v5` tier three target) r? `@ghost` `@rustbot` modify labels: rollup
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Rollup merge of #144899 - Kobzol:cgu-reuse, r=saethlin Print CGU reuse statistics in `-Zprint-mono-items` I'm trying to expose more information about incremental profiling from rustc (https://rust-lang.zulipchat.com/#narrow/channel/131828-t-compiler/topic/Profiling.2Fanalysis.20of.20incremental.20builds/with/531383501). One of the things that would be quite useful to expose is the CGU reuse state, so that when you do a rebuild, you can see all the CGUs (and all the functions) that had to be recompiled. Currently, we have (AFAIK) two ways of outputting monomorphization statistics: 1) `-Zdump-mono-stats` outputs statistics about number of instantiations and expected compilation cost of individual functions in the local crate being compiled. It can be outputted either as Markdown or JSON. 2) `-Zprint-mono-items` outputs a pair (item, CGU) for each monomorphized item. I was thinking about recording CGU statistics in the self-profile output, but I realized that as a simpler step, we could just add CGU reuse data to `-Zprint-mono-items`, as an additional output. That is what this PR does.
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I'm trying to expose more information about incremental profiling from rustc (https://rust-lang.zulipchat.com/#narrow/channel/131828-t-compiler/topic/Profiling.2Fanalysis.20of.20incremental.20builds/with/531383501). One of the things that would be quite useful to expose is the CGU reuse state, so that when you do a rebuild, you can see all the CGUs (and all the functions) that had to be recompiled.
Currently, we have (AFAIK) two ways of outputting monomorphization statistics:
-Zdump-mono-statsoutputs statistics about number of instantiations and expected compilation cost of individual functions in the local crate being compiled. It can be outputted either as Markdown or JSON.-Zprint-mono-itemsoutputs a pair (item, CGU) for each monomorphized item.I was thinking about recording CGU statistics in the self-profile output, but I realized that as a simpler step, we could just add CGU reuse data to
-Zprint-mono-items, as an additional output. That is what this PR does.