forked from rust-lang/rust
-
Notifications
You must be signed in to change notification settings - Fork 6
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
Auto merge of rust-lang#116505 - saethlin:infer-inline, r=<try>
Automatically enable cross-crate inlining for small functions This is basically reviving rust-lang#70550 The `#[inline]` attribute can have a significant impact on code generation or runtime performance (because it enables inlining between CGUs where it would normally not happen) and also on compile-time performance (because it enables MIR inlining). But it has to be added manually, which is awkward. This PR factors whether a DefId is cross-crate inlinable into a query, and replaces all uses of `CodegenFnAttrs::requests_inline` with this new query. The new query incorporates all the other logic that is used to determine whether a Def should be treated as cross-crate-inlinable, and as a last step inspects the function's optimized_mir to determine if it should be treated as cross-crate-inlinable. The heuristic implemented here is deliberately conservative; we only infer inlinability for functions whose optimized_mir does not contain any calls or asserts. I plan to study adjusting the cost model later, but for now the compile time implications of this change are so significant that I think this very crude heuristic is well worth landing.
- Loading branch information
Showing
75 changed files
with
470 additions
and
363 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,119 @@ | ||
| use rustc_attr::InlineAttr; | ||
| use rustc_hir::def::DefKind; | ||
| use rustc_hir::def_id::LocalDefId; | ||
| use rustc_middle::mir::visit::Visitor; | ||
| use rustc_middle::mir::*; | ||
| use rustc_middle::query::Providers; | ||
| use rustc_middle::ty::TyCtxt; | ||
| use rustc_session::config::OptLevel; | ||
|
|
||
| pub fn provide(providers: &mut Providers) { | ||
| providers.cross_crate_inlinable = cross_crate_inlinable; | ||
| } | ||
|
|
||
| fn cross_crate_inlinable(tcx: TyCtxt<'_>, def_id: LocalDefId) -> bool { | ||
| let codegen_fn_attrs = tcx.codegen_fn_attrs(def_id); | ||
| // If this has an extern indicator, then this function is globally shared and thus will not | ||
| // generate cgu-internal copies which would make it cross-crate inlinable. | ||
| if codegen_fn_attrs.contains_extern_indicator() { | ||
| return false; | ||
| } | ||
|
|
||
| // Obey source annotations first; this is important because it means we can use | ||
| // #[inline(never)] to force code generation. | ||
| match codegen_fn_attrs.inline { | ||
| InlineAttr::Never => return false, | ||
| InlineAttr::Hint | InlineAttr::Always => return true, | ||
| _ => {} | ||
| } | ||
|
|
||
| // This just reproduces the logic from Instance::requires_inline. | ||
| match tcx.def_kind(def_id) { | ||
| DefKind::Ctor(..) | DefKind::Closure => return true, | ||
| DefKind::Fn | DefKind::AssocFn => {} | ||
| _ => return false, | ||
| } | ||
|
|
||
| // Don't do any inference when incremental compilation is enabled; the additional inlining that | ||
| // inference permits also creates more work for small edits. | ||
| if tcx.sess.opts.incremental.is_some() { | ||
| return false; | ||
| } | ||
|
|
||
| // Don't do any inference unless optimizations are enabled. | ||
| if matches!(tcx.sess.opts.optimize, OptLevel::No) { | ||
| return false; | ||
| } | ||
|
|
||
| if !tcx.is_mir_available(def_id) { | ||
| return false; | ||
| } | ||
|
|
||
| let mir = tcx.optimized_mir(def_id); | ||
| let mut checker = | ||
| CostChecker { tcx, callee_body: mir, calls: 0, statements: 0, landing_pads: 0, resumes: 0 }; | ||
| checker.visit_body(mir); | ||
| checker.calls == 0 | ||
| && checker.resumes == 0 | ||
| && checker.landing_pads == 0 | ||
| && checker.statements | ||
| <= tcx.sess.opts.unstable_opts.cross_crate_inline_threshold.unwrap_or(100) | ||
| } | ||
|
|
||
| struct CostChecker<'b, 'tcx> { | ||
| tcx: TyCtxt<'tcx>, | ||
| callee_body: &'b Body<'tcx>, | ||
| calls: usize, | ||
| statements: usize, | ||
| landing_pads: usize, | ||
| resumes: usize, | ||
| } | ||
|
|
||
| impl<'tcx> Visitor<'tcx> for CostChecker<'_, 'tcx> { | ||
| fn visit_statement(&mut self, statement: &Statement<'tcx>, _: Location) { | ||
| // Don't count StorageLive/StorageDead in the inlining cost. | ||
| match statement.kind { | ||
| StatementKind::StorageLive(_) | ||
| | StatementKind::StorageDead(_) | ||
| | StatementKind::Deinit(_) | ||
| | StatementKind::Nop => {} | ||
| _ => self.statements += 1, | ||
| } | ||
| } | ||
|
|
||
| fn visit_terminator(&mut self, terminator: &Terminator<'tcx>, _: Location) { | ||
| let tcx = self.tcx; | ||
| match terminator.kind { | ||
| TerminatorKind::Drop { ref place, unwind, .. } => { | ||
| let ty = place.ty(self.callee_body, tcx).ty; | ||
| if !ty.is_trivially_pure_clone_copy() { | ||
| self.calls += 1; | ||
| if let UnwindAction::Cleanup(_) = unwind { | ||
| self.landing_pads += 1; | ||
| } | ||
| } | ||
| } | ||
| TerminatorKind::Call { unwind, .. } => { | ||
| self.calls += 1; | ||
| if let UnwindAction::Cleanup(_) = unwind { | ||
| self.landing_pads += 1; | ||
| } | ||
| } | ||
| TerminatorKind::Assert { unwind, .. } => { | ||
| self.calls += 1; | ||
| if let UnwindAction::Cleanup(_) = unwind { | ||
| self.landing_pads += 1; | ||
| } | ||
| } | ||
| TerminatorKind::UnwindResume => self.resumes += 1, | ||
| TerminatorKind::InlineAsm { unwind, .. } => { | ||
| self.statements += 1; | ||
| if let UnwindAction::Cleanup(_) = unwind { | ||
| self.landing_pads += 1; | ||
| } | ||
| } | ||
| TerminatorKind::Return => {} | ||
| _ => self.statements += 1, | ||
| } | ||
| } | ||
| } |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Oops, something went wrong.