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, OptLevel};
use rustc_span::sym;
use crate::{inline, pass_manager as pm};
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 codegen_fn_attrs.contains_extern_indicator() {
return false;
}
match tcx.def_kind(def_id) {
DefKind::Ctor(..) | DefKind::Closure => return true,
DefKind::Fn | DefKind::AssocFn => {}
_ => return false,
}
if tcx.sess.opts.unstable_opts.cross_crate_inline_threshold == InliningThreshold::Always {
return true;
}
if tcx.has_attr(def_id, sym::rustc_intrinsic) {
return true;
}
match codegen_fn_attrs.inline {
InlineAttr::Never => return false,
InlineAttr::Hint | InlineAttr::Always => return true,
_ => {}
}
if tcx.sess.opts.incremental.is_some() {
return false;
}
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) {
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,
}
}
}