src/abi/returning.rs

   1 use crate::abi::pass_mode::*;
   2 use crate::prelude::*;
   3
   4 pub fn codegen_return_param(
   5     fx: &mut FunctionCx<impl Backend>,
   6     ssa_analyzed: &HashMap<Local, crate::analyze::SsaKind>,
   7     start_ebb: Ebb,
   8 ) {
   9     let ret_layout = fx.return_layout();
  10     let output_pass_mode = get_pass_mode(fx.tcx, fx.return_layout());
  11
  12     let ret_param = match output_pass_mode {
  13         PassMode::NoPass => {
  14             fx.local_map
  15                 .insert(RETURN_PLACE, CPlace::no_place(ret_layout));
  16             Empty
  17         }
  18         PassMode::ByVal(_) | PassMode::ByValPair(_, _) => {
  19             let is_ssa =
  20                 *ssa_analyzed.get(&RETURN_PLACE).unwrap() == crate::analyze::SsaKind::Ssa;
  21
  22             super::local_place(fx, RETURN_PLACE, ret_layout, is_ssa);
  23
  24             Empty
  25         }
  26         PassMode::ByRef => {
  27             let ret_param = fx.bcx.append_ebb_param(start_ebb, fx.pointer_type);
  28             fx.local_map
  29                 .insert(RETURN_PLACE, CPlace::for_addr(ret_param, ret_layout));
  30
  31             Single(ret_param)
  32         }
  33     };
  34
  35     #[cfg(debug_assertions)]
  36     crate::abi::comments::add_arg_comment(
  37         fx,
  38         "ret",
  39         RETURN_PLACE,
  40         None,
  41         ret_param,
  42         output_pass_mode,
  43         ret_layout.ty,
  44     );
  45 }
  46
  47 pub fn codegen_with_call_return_arg<'tcx, B: Backend, T>(
  48     fx: &mut FunctionCx<'_, 'tcx, B>,
  49     fn_sig: FnSig<'tcx>,
  50     ret_place: Option<CPlace<'tcx>>,
  51     f: impl FnOnce(&mut FunctionCx<'_, 'tcx, B>, Option<Value>) -> (Inst, T),
  52 ) -> (Inst, T) {
  53     let ret_layout = fx.layout_of(fn_sig.output());
  54
  55     let output_pass_mode = get_pass_mode(fx.tcx, ret_layout);
  56     let return_ptr = match output_pass_mode {
  57         PassMode::NoPass => None,
  58         PassMode::ByRef => match ret_place {
  59             Some(ret_place) => Some(ret_place.to_addr(fx)),
  60             None => Some(fx.bcx.ins().iconst(fx.pointer_type, 43)),
  61         },
  62         PassMode::ByVal(_) | PassMode::ByValPair(_, _) => None,
  63     };
  64
  65     let (call_inst, meta) = f(fx, return_ptr);
  66
  67     match output_pass_mode {
  68         PassMode::NoPass => {}
  69         PassMode::ByVal(_) => {
  70             if let Some(ret_place) = ret_place {
  71                 let ret_val = fx.bcx.inst_results(call_inst)[0];
  72                 ret_place.write_cvalue(fx, CValue::by_val(ret_val, ret_layout));
  73             }
  74         }
  75         PassMode::ByValPair(_, _) => {
  76             if let Some(ret_place) = ret_place {
  77                 let ret_val_a = fx.bcx.inst_results(call_inst)[0];
  78                 let ret_val_b = fx.bcx.inst_results(call_inst)[1];
  79                 ret_place.write_cvalue(fx, CValue::by_val_pair(ret_val_a, ret_val_b, ret_layout));
  80             }
  81         }
  82         PassMode::ByRef => {}
  83     }
  84
  85     (call_inst, meta)
  86 }
  87
  88 pub fn codegen_return(fx: &mut FunctionCx<impl Backend>) {
  89     match get_pass_mode(fx.tcx, fx.return_layout()) {
  90         PassMode::NoPass | PassMode::ByRef => {
  91             fx.bcx.ins().return_(&[]);
  92         }
  93         PassMode::ByVal(_) => {
  94             let place = fx.get_local_place(RETURN_PLACE);
  95             let ret_val = place.to_cvalue(fx).load_scalar(fx);
  96             fx.bcx.ins().return_(&[ret_val]);
  97         }
  98         PassMode::ByValPair(_, _) => {
  99             let place = fx.get_local_place(RETURN_PLACE);
 100             let (ret_val_a, ret_val_b) = place.to_cvalue(fx).load_scalar_pair(fx);
 101             fx.bcx.ins().return_(&[ret_val_a, ret_val_b]);
 102         }
 103     }
 104 }