| use crate::inline; |
| use crate::pass_manager as pm; |
| 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::InliningThreshold; |
| 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 if codegen optimizations are disabled and also MIR inlining is not |
| // enabled. This ensures that we do inference even if someone only passes -Zinline-mir, |
| // which is less confusing than having to also enable -Copt-level=1. |
| if matches!(tcx.sess.opts.optimize, OptLevel::No) && !pm::should_run_pass(tcx, &inline::Inline) |
| { |
| return false; |
| } |
| |
| if !tcx.is_mir_available(def_id) { |
| return false; |
| } |
| |
| let threshold = match tcx.sess.opts.unstable_opts.cross_crate_inline_threshold { |
| InliningThreshold::Always => return true, |
| InliningThreshold::Sometimes(threshold) => threshold, |
| InliningThreshold::Never => 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 <= threshold |
| } |
| |
| 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, |
| } |
| } |
| } |