Box `ast::ItemKind` #81400

jyn514 · 2021-01-25T23:54:54Z

This reduces the size of ast::Item from 296 to 96 bytes.

See https://rust-lang.zulipchat.com/#narrow/stream/247081-t-compiler.2Fperformance/topic/windows-rs.20perf/near/223974946 for context; the hope is this will save memory compiling windows-rs.

This reduces the size of ast::Item from 296 to 96 bytes.

rust-highfive · 2021-01-25T23:54:57Z

r? @davidtwco

(rust-highfive has picked a reviewer for you, use r? to override)

jyn514 · 2021-01-25T23:55:06Z

@bors try @rust-timer queue

rust-timer · 2021-01-25T23:55:07Z

Awaiting bors try build completion.

bors · 2021-01-25T23:55:16Z

⌛ Trying commit 6f5d4b8 with merge 76f647b0d68bb484dfaf12d4025354e07fdda7c6...

rust-log-analyzer · 2021-01-26T00:03:30Z

The job mingw-check failed! Check out the build log: (web) (plain)

Click to see the possible cause of the failure (guessed by this bot)

configure: rust.channel         := nightly
configure: rust.debug-assertions := True
configure: llvm.assertions      := True
configure: dist.missing-tools   := True
configure: build.configure-args := ['--enable-sccache', '--disable-manage-submodu ...
configure: writing `config.toml` in current directory
configure: 
configure: run `python /checkout/x.py --help`
configure: 
---
    Checking rustc_parse_format v0.0.0 (/checkout/compiler/rustc_parse_format)
error[E0308]: mismatched types
    --> /checkout/compiler/rustc_data_structures/src/macros.rs:5:32
     |
3    | / macro_rules! static_assert_size {
4    | |     ($ty:ty, $size:expr) => {
5    | |         const _: [(); $size] = [(); ::std::mem::size_of::<$ty>()];
     | |                                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected an array with a fixed size of 96 elements, found one with 68 elements
7    | | }
     | |_- in this expansion of `rustc_data_structures::static_assert_size!`
     | 
    ::: compiler/rustc_ast/src/ast.rs:2596:1
    ::: compiler/rustc_ast/src/ast.rs:2596:1
     |
2596 |   rustc_data_structures::static_assert_size!(Item<ItemKind>, 96);
     |   --------------------------------------------------------------- in this macro invocation
error[E0308]: mismatched types
    --> /checkout/compiler/rustc_data_structures/src/macros.rs:5:32
     |
3    | / macro_rules! static_assert_size {
3    | / macro_rules! static_assert_size {
4    | |     ($ty:ty, $size:expr) => {
5    | |         const _: [(); $size] = [(); ::std::mem::size_of::<$ty>()];
     | |                                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected an array with a fixed size of 96 elements, found one with 68 elements
7    | | }
     | |_- in this expansion of `rustc_data_structures::static_assert_size!`
     | 
    ::: compiler/rustc_ast/src/ast.rs:2597:1
    ::: compiler/rustc_ast/src/ast.rs:2597:1
     |
2597 |   rustc_data_structures::static_assert_size!(Item<AssocItemKind>, 96);
     |   -------------------------------------------------------------------- in this macro invocation
error[E0308]: mismatched types
    --> /checkout/compiler/rustc_data_structures/src/macros.rs:5:32
     |
3    | / macro_rules! static_assert_size {
3    | / macro_rules! static_assert_size {
4    | |     ($ty:ty, $size:expr) => {
5    | |         const _: [(); $size] = [(); ::std::mem::size_of::<$ty>()];
     | |                                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected an array with a fixed size of 96 elements, found one with 68 elements
7    | | }
     | |_- in this expansion of `rustc_data_structures::static_assert_size!`
     | 
    ::: compiler/rustc_ast/src/ast.rs:2598:1
    ::: compiler/rustc_ast/src/ast.rs:2598:1
     |
2598 |   rustc_data_structures::static_assert_size!(Item<ForeignItemKind>, 96);
     |   ---------------------------------------------------------------------- in this macro invocation
error[E0308]: mismatched types
    --> /checkout/compiler/rustc_data_structures/src/macros.rs:5:32
     |
3    | / macro_rules! static_assert_size {
3    | / macro_rules! static_assert_size {
4    | |     ($ty:ty, $size:expr) => {
5    | |         const _: [(); $size] = [(); ::std::mem::size_of::<$ty>()];
     | |                                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected an array with a fixed size of 96 elements, found one with 68 elements
7    | | }
     | |_- in this expansion of `rustc_data_structures::static_assert_size!`
     | 
    ::: compiler/rustc_ast/src/ast.rs:2596:1
    ::: compiler/rustc_ast/src/ast.rs:2596:1
     |
2596 |   rustc_data_structures::static_assert_size!(Item<ItemKind>, 96);
     |   --------------------------------------------------------------- in this macro invocation
error[E0308]: mismatched types
    --> /checkout/compiler/rustc_data_structures/src/macros.rs:5:32
     |
3    | / macro_rules! static_assert_size {
3    | / macro_rules! static_assert_size {
4    | |     ($ty:ty, $size:expr) => {
5    | |         const _: [(); $size] = [(); ::std::mem::size_of::<$ty>()];
     | |                                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected an array with a fixed size of 96 elements, found one with 68 elements
7    | | }
     | |_- in this expansion of `rustc_data_structures::static_assert_size!`
     | 
    ::: compiler/rustc_ast/src/ast.rs:2597:1
    ::: compiler/rustc_ast/src/ast.rs:2597:1
     |
2597 |   rustc_data_structures::static_assert_size!(Item<AssocItemKind>, 96);
     |   -------------------------------------------------------------------- in this macro invocation
error[E0308]: mismatched types
    --> /checkout/compiler/rustc_data_structures/src/macros.rs:5:32
     |
3    | / macro_rules! static_assert_size {
3    | / macro_rules! static_assert_size {
4    | |     ($ty:ty, $size:expr) => {
5    | |         const _: [(); $size] = [(); ::std::mem::size_of::<$ty>()];
     | |                                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected an array with a fixed size of 96 elements, found one with 68 elements
7    | | }
     | |_- in this expansion of `rustc_data_structures::static_assert_size!`
     | 
    ::: compiler/rustc_ast/src/ast.rs:2598:1
    ::: compiler/rustc_ast/src/ast.rs:2598:1
     |
2598 |   rustc_data_structures::static_assert_size!(Item<ForeignItemKind>, 96);
     |   ---------------------------------------------------------------------- in this macro invocation
    Checking tracing-serde v0.1.2
    Checking gsgdt v0.1.2
    Checking rls-span v0.5.3
    Checking rls-data v0.19.1
---
error: aborting due to 3 previous errors

For more information about this error, try `rustc --explain E0308`.
error: build failed
command did not execute successfully: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage0/bin/cargo" "check" "--target" "i686-pc-windows-gnu" "-Zbinary-dep-depinfo" "-j" "16" "--release" "--locked" "--color" "always" "--features" " llvm" "--manifest-path" "/checkout/compiler/rustc/Cargo.toml" "--all-targets" "-p" "rustc-main" "-p" "rustc_driver" "-p" "rustc_mir" "-p" "rustc_graphviz" "-p" "rustc_index" "-p" "rustc_trait_selection" "-p" "rustc_parse_format" "-p" "rustc_attr" "-p" "rustc_infer" "-p" "coverage_test_macros" "-p" "rustc_macros" "-p" "rustc_apfloat" "-p" "rustc_lexer" "-p" "rustc_lint" "-p" "rustc_error_codes" "-p" "rustc_plugin_impl" "-p" "rustc_interface" "-p" "rustc_passes" "-p" "rustc_resolve" "-p" "rustc_arena" "-p" "rustc_ast_passes" "-p" "rustc_privacy" "-p" "rustc_incremental" "-p" "rustc_fs_util" "-p" "rustc_symbol_mangling" "-p" "rustc_expand" "-p" "rustc_builtin_macros" "-p" "rustc_typeck" "-p" "rustc_ast_lowering" "-p" "rustc_traits" "-p" "rustc_mir_build" "-p" "rustc_codegen_llvm" "-p" "rustc_llvm" "-p" "rustc_ty_utils" "-p" "rustc_save_analysis" "-p" "rustc_session" "-p" "rustc_lint_defs" "-p" "rustc_parse" "-p" "rustc_errors" "-p" "rustc_serialize" "-p" "rustc_hir_pretty" "-p" "rustc_feature" "-p" "rustc_hir" "-p" "rustc_middle" "-p" "rustc_type_ir" "-p" "rustc_query_system" "-p" "rustc_data_structures" "-p" "rustc_ast" "-p" "rustc_target" "-p" "rustc_ast_pretty" "-p" "rustc_metadata" "-p" "rustc_span" "-p" "rustc_codegen_ssa" "--message-format" "json-render-diagnostics"
failed to run: /checkout/obj/build/bootstrap/debug/bootstrap check --target=i686-pc-windows-gnu --host=i686-pc-windows-gnu --all-targets
Build completed unsuccessfully in 0:01:16

bors · 2021-01-26T00:42:02Z

☀️ Try build successful - checks-actions
Build commit: 76f647b0d68bb484dfaf12d4025354e07fdda7c6 (76f647b0d68bb484dfaf12d4025354e07fdda7c6)

rust-timer · 2021-01-26T00:42:04Z

Queued 76f647b0d68bb484dfaf12d4025354e07fdda7c6 with parent f4eb5d9, future comparison URL.

@rustbot label: +S-waiting-on-perf

ThePuzzlemaker · 2021-01-26T01:46:45Z

The fact that this had to be done genuinely scares me.

rust-timer · 2021-01-26T02:21:18Z

Finished benchmarking try commit (76f647b0d68bb484dfaf12d4025354e07fdda7c6): comparison url.

Benchmarking this pull request likely means that it is perf-sensitive, so we're automatically marking it as not fit for rolling up. Please note that if the perf results are neutral, you should likely undo the rollup=never given below by specifying rollup- to bors.

Importantly, though, if the results of this run are non-neutral do not roll this PR up -- it will mask other regressions or improvements in the roll up.

@bors rollup=never
@rustbot label: +S-waiting-on-review -S-waiting-on-perf

cynecx · 2021-01-26T04:10:51Z

compiler/rustc_ast/src/ast.rs

@@ -2593,6 +2593,10 @@ pub struct Item<K = ItemKind> {
    pub tokens: Option<LazyTokenStream>,
 }

+rustc_data_structures::static_assert_size!(Item<ItemKind>, 96);


Does this account for pointer size differences across platforms?

bugadani · 2021-01-26T06:37:17Z

Well this has the exact opposite effect: increasing memory use. On the flip side, a small perf gain.

bugadani · 2021-01-26T06:50:47Z

The biggest ItemKind variants are:

Impl: 200 bytes
Fn: 176 bytes
Trait: 136 bytes
TyAlias: 120 bytes

davidtwco · 2021-01-30T13:53:27Z

Should this be closed in favour of #81405 or are there more things you'd like to try here @jyn514?

jyn514 · 2021-01-30T14:40:12Z

I'm not planning to follow up on this.

Box the biggest ast::ItemKind variants This PR is a different approach on rust-lang#81400, aiming to save memory in humongous ASTs. The three affected item kind enums are: - `ast::ItemKind` (208 -> 112 bytes) - `ast::AssocItemKind` (176 -> 72 bytes) - `ast::ForeignItemKind` (176 -> 72 bytes)

Box the biggest ast::ItemKind variants This PR is a different approach on rust-lang/rust#81400, aiming to save memory in humongous ASTs. The three affected item kind enums are: - `ast::ItemKind` (208 -> 112 bytes) - `ast::AssocItemKind` (176 -> 72 bytes) - `ast::ForeignItemKind` (176 -> 72 bytes)

Box ast::ItemKind

6f5d4b8

This reduces the size of ast::Item from 296 to 96 bytes.

jyn514 added A-parser Area: The lexing & parsing of Rust source code to an AST T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. I-compilemem Issue: Problems and improvements with respect to memory usage during compilation. labels Jan 25, 2021

rust-highfive assigned davidtwco Jan 25, 2021

rust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Jan 25, 2021

rustbot added the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Jan 26, 2021

rustbot removed the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Jan 26, 2021

cynecx reviewed Jan 26, 2021

View reviewed changes

bugadani mentioned this pull request Jan 26, 2021

Box the biggest ast::ItemKind variants #81405

Merged

davidtwco added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Jan 30, 2021

jyn514 closed this Jan 30, 2021

jyn514 deleted the box-ast-kind branch January 30, 2021 14:40

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Box `ast::ItemKind` #81400

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