bjoernager/rust
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Give CostChecker both penalties and bonuses

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This commit is contained in:
Scott McMurray 2024-06-16 23:44:29 -07:00
parent 3d5d7a24f7
commit f334951030
1 changed files with 16 additions and 15 deletions
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31
compiler/rustc_mir_transform/src/cost_checker.rs
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@ -12,7 +12,8 @@ const RESUME_PENALTY: usize = 45;
pub(crate) struct CostChecker<'b, 'tcx> { pub(crate) struct CostChecker<'b, 'tcx> {
tcx: TyCtxt<'tcx>, tcx: TyCtxt<'tcx>,
param_env: ParamEnv<'tcx>, param_env: ParamEnv<'tcx>,
cost: usize, penalty: usize,
bonus: usize,
callee_body: &'b Body<'tcx>, callee_body: &'b Body<'tcx>,
instance: Option<ty::Instance<'tcx>>, instance: Option<ty::Instance<'tcx>>,
} }
@ -24,11 +25,11 @@ impl<'b, 'tcx> CostChecker<'b, 'tcx> {
instance: Option<ty::Instance<'tcx>>, instance: Option<ty::Instance<'tcx>>,
callee_body: &'b Body<'tcx>, callee_body: &'b Body<'tcx>,
) -> CostChecker<'b, 'tcx> { ) -> CostChecker<'b, 'tcx> {
CostChecker { tcx, param_env, callee_body, instance, cost: 0 } CostChecker { tcx, param_env, callee_body, instance, penalty: 0, bonus: 0 }
} }
pub fn cost(&self) -> usize { pub fn cost(&self) -> usize {
self.cost usize::saturating_sub(self.penalty, self.bonus)
} }
fn instantiate_ty(&self, v: Ty<'tcx>) -> Ty<'tcx> { fn instantiate_ty(&self, v: Ty<'tcx>) -> Ty<'tcx> {
@ -48,7 +49,7 @@ impl<'tcx> Visitor<'tcx> for CostChecker<'_, 'tcx> {
| StatementKind::StorageDead(_) | StatementKind::StorageDead(_)
| StatementKind::Deinit(_) | StatementKind::Deinit(_)
| StatementKind::Nop => {} | StatementKind::Nop => {}
_ => self.cost += INSTR_COST, _ => self.penalty += INSTR_COST,
} }
} }
@ -59,17 +60,17 @@ impl<'tcx> Visitor<'tcx> for CostChecker<'_, 'tcx> {
// If the place doesn't actually need dropping, treat it like a regular goto. // If the place doesn't actually need dropping, treat it like a regular goto.
let ty = self.instantiate_ty(place.ty(self.callee_body, tcx).ty); let ty = self.instantiate_ty(place.ty(self.callee_body, tcx).ty);
if ty.needs_drop(tcx, self.param_env) { if ty.needs_drop(tcx, self.param_env) {
self.cost += CALL_PENALTY; self.penalty += CALL_PENALTY;
if let UnwindAction::Cleanup(_) = unwind { if let UnwindAction::Cleanup(_) = unwind {
self.cost += LANDINGPAD_PENALTY; self.penalty += LANDINGPAD_PENALTY;
} }
} else { } else {
self.cost += INSTR_COST; self.penalty += INSTR_COST;
} }
} }
TerminatorKind::Call { func: Operand::Constant(ref f), unwind, .. } => { TerminatorKind::Call { func: Operand::Constant(ref f), unwind, .. } => {
let fn_ty = self.instantiate_ty(f.const_.ty()); let fn_ty = self.instantiate_ty(f.const_.ty());
self.cost += if let ty::FnDef(def_id, _) = *fn_ty.kind() self.penalty += if let ty::FnDef(def_id, _) = *fn_ty.kind()
&& tcx.intrinsic(def_id).is_some() && tcx.intrinsic(def_id).is_some()
{ {
// Don't give intrinsics the extra penalty for calls // Don't give intrinsics the extra penalty for calls
@ -78,23 +79,23 @@ impl<'tcx> Visitor<'tcx> for CostChecker<'_, 'tcx> {
CALL_PENALTY CALL_PENALTY
}; };
if let UnwindAction::Cleanup(_) = unwind { if let UnwindAction::Cleanup(_) = unwind {
self.cost += LANDINGPAD_PENALTY; self.penalty += LANDINGPAD_PENALTY;
} }
} }
TerminatorKind::Assert { unwind, .. } => { TerminatorKind::Assert { unwind, .. } => {
self.cost += CALL_PENALTY; self.penalty += CALL_PENALTY;
if let UnwindAction::Cleanup(_) = unwind { if let UnwindAction::Cleanup(_) = unwind {
self.cost += LANDINGPAD_PENALTY; self.penalty += LANDINGPAD_PENALTY;
} }
} }
TerminatorKind::UnwindResume => self.cost += RESUME_PENALTY, TerminatorKind::UnwindResume => self.penalty += RESUME_PENALTY,
TerminatorKind::InlineAsm { unwind, .. } => { TerminatorKind::InlineAsm { unwind, .. } => {
self.cost += INSTR_COST; self.penalty += INSTR_COST;
if let UnwindAction::Cleanup(_) = unwind { if let UnwindAction::Cleanup(_) = unwind {
self.cost += LANDINGPAD_PENALTY; self.penalty += LANDINGPAD_PENALTY;
} }
} }
_ => self.cost += INSTR_COST, _ => self.penalty += INSTR_COST,
} }
} }
} }