compiler/rustc_codegen_cranelift/src/codegen_i128.rs

   1 //! Replaces 128-bit operators with lang item calls where necessary
   2
   3 use cranelift_codegen::ir::ArgumentPurpose;
   4
   5 use crate::prelude::*;
   6
   7 pub(crate) fn maybe_codegen<'tcx>(
   8     fx: &mut FunctionCx<'_, '_, 'tcx>,
   9     bin_op: BinOp,
  10     checked: bool,
  11     lhs: CValue<'tcx>,
  12     rhs: CValue<'tcx>,
  13 ) -> Option<CValue<'tcx>> {
  14     if lhs.layout().ty != fx.tcx.types.u128
  15         && lhs.layout().ty != fx.tcx.types.i128
  16         && rhs.layout().ty != fx.tcx.types.u128
  17         && rhs.layout().ty != fx.tcx.types.i128
  18     {
  19         return None;
  20     }
  21
  22     let lhs_val = lhs.load_scalar(fx);
  23     let rhs_val = rhs.load_scalar(fx);
  24
  25     let is_signed = type_sign(lhs.layout().ty);
  26
  27     match bin_op {
  28         BinOp::BitAnd | BinOp::BitOr | BinOp::BitXor => {
  29             assert!(!checked);
  30             None
  31         }
  32         BinOp::Add | BinOp::Sub if !checked => None,
  33         BinOp::Mul if !checked => {
  34             let val_ty = if is_signed { fx.tcx.types.i128 } else { fx.tcx.types.u128 };
  35             if fx.tcx.sess.target.is_like_windows {
  36                 let ret_place = CPlace::new_stack_slot(fx, lhs.layout());
  37                 let (lhs_ptr, lhs_extra) = lhs.force_stack(fx);
  38                 let (rhs_ptr, rhs_extra) = rhs.force_stack(fx);
  39                 assert!(lhs_extra.is_none());
  40                 assert!(rhs_extra.is_none());
  41                 let args =
  42                     [ret_place.to_ptr().get_addr(fx), lhs_ptr.get_addr(fx), rhs_ptr.get_addr(fx)];
  43                 fx.lib_call(
  44                     "__multi3",
  45                     vec![
  46                         AbiParam::special(pointer_ty(fx.tcx), ArgumentPurpose::StructReturn),
  47                         AbiParam::new(pointer_ty(fx.tcx)),
  48                         AbiParam::new(pointer_ty(fx.tcx)),
  49                     ],
  50                     vec![],
  51                     &args,
  52                 );
  53                 Some(ret_place.to_cvalue(fx))
  54             } else {
  55                 Some(fx.easy_call("__multi3", &[lhs, rhs], val_ty))
  56             }
  57         }
  58         BinOp::Add | BinOp::Sub | BinOp::Mul => {
  59             assert!(checked);
  60             let out_ty = fx.tcx.mk_tup([lhs.layout().ty, fx.tcx.types.bool].iter());
  61             let out_place = CPlace::new_stack_slot(fx, fx.layout_of(out_ty));
  62             let (param_types, args) = if fx.tcx.sess.target.is_like_windows {
  63                 let (lhs_ptr, lhs_extra) = lhs.force_stack(fx);
  64                 let (rhs_ptr, rhs_extra) = rhs.force_stack(fx);
  65                 assert!(lhs_extra.is_none());
  66                 assert!(rhs_extra.is_none());
  67                 (
  68                     vec![
  69                         AbiParam::special(pointer_ty(fx.tcx), ArgumentPurpose::StructReturn),
  70                         AbiParam::new(pointer_ty(fx.tcx)),
  71                         AbiParam::new(pointer_ty(fx.tcx)),
  72                     ],
  73                     [out_place.to_ptr().get_addr(fx), lhs_ptr.get_addr(fx), rhs_ptr.get_addr(fx)],
  74                 )
  75             } else {
  76                 (
  77                     vec![
  78                         AbiParam::special(pointer_ty(fx.tcx), ArgumentPurpose::StructReturn),
  79                         AbiParam::new(types::I128),
  80                         AbiParam::new(types::I128),
  81                     ],
  82                     [out_place.to_ptr().get_addr(fx), lhs.load_scalar(fx), rhs.load_scalar(fx)],
  83                 )
  84             };
  85             let name = match (bin_op, is_signed) {
  86                 (BinOp::Add, false) => "__rust_u128_addo",
  87                 (BinOp::Add, true) => "__rust_i128_addo",
  88                 (BinOp::Sub, false) => "__rust_u128_subo",
  89                 (BinOp::Sub, true) => "__rust_i128_subo",
  90                 (BinOp::Mul, false) => "__rust_u128_mulo",
  91                 (BinOp::Mul, true) => "__rust_i128_mulo",
  92                 _ => unreachable!(),
  93             };
  94             fx.lib_call(name, param_types, vec![], &args);
  95             Some(out_place.to_cvalue(fx))
  96         }
  97         BinOp::Offset => unreachable!("offset should only be used on pointers, not 128bit ints"),
  98         BinOp::Div | BinOp::Rem => {
  99             assert!(!checked);
 100             let name = match (bin_op, is_signed) {
 101                 (BinOp::Div, false) => "__udivti3",
 102                 (BinOp::Div, true) => "__divti3",
 103                 (BinOp::Rem, false) => "__umodti3",
 104                 (BinOp::Rem, true) => "__modti3",
 105                 _ => unreachable!(),
 106             };
 107             if fx.tcx.sess.target.is_like_windows {
 108                 let (lhs_ptr, lhs_extra) = lhs.force_stack(fx);
 109                 let (rhs_ptr, rhs_extra) = rhs.force_stack(fx);
 110                 assert!(lhs_extra.is_none());
 111                 assert!(rhs_extra.is_none());
 112                 let args = [lhs_ptr.get_addr(fx), rhs_ptr.get_addr(fx)];
 113                 let ret = fx.lib_call(
 114                     name,
 115                     vec![AbiParam::new(pointer_ty(fx.tcx)), AbiParam::new(pointer_ty(fx.tcx))],
 116                     vec![AbiParam::new(types::I64X2)],
 117                     &args,
 118                 )[0];
 119                 // FIXME use bitcast instead of store to get from i64x2 to i128
 120                 let ret_place = CPlace::new_stack_slot(fx, lhs.layout());
 121                 ret_place.to_ptr().store(fx, ret, MemFlags::trusted());
 122                 Some(ret_place.to_cvalue(fx))
 123             } else {
 124                 Some(fx.easy_call(name, &[lhs, rhs], lhs.layout().ty))
 125             }
 126         }
 127         BinOp::Lt | BinOp::Le | BinOp::Eq | BinOp::Ge | BinOp::Gt | BinOp::Ne => {
 128             assert!(!checked);
 129             None
 130         }
 131         BinOp::Shl | BinOp::Shr => {
 132             let is_overflow = if checked {
 133                 // rhs >= 128
 134
 135                 // FIXME support non 128bit rhs
 136                 /*let (rhs_lsb, rhs_msb) = fx.bcx.ins().isplit(rhs_val);
 137                 let rhs_msb_gt_0 = fx.bcx.ins().icmp_imm(IntCC::NotEqual, rhs_msb, 0);
 138                 let rhs_lsb_ge_128 = fx.bcx.ins().icmp_imm(IntCC::SignedGreaterThan, rhs_lsb, 127);
 139                 let is_overflow = fx.bcx.ins().bor(rhs_msb_gt_0, rhs_lsb_ge_128);*/
 140                 let is_overflow = fx.bcx.ins().bconst(types::B1, false);
 141
 142                 Some(fx.bcx.ins().bint(types::I8, is_overflow))
 143             } else {
 144                 None
 145             };
 146
 147             let truncated_rhs = clif_intcast(fx, rhs_val, types::I32, false);
 148             let val = match bin_op {
 149                 BinOp::Shl => fx.bcx.ins().ishl(lhs_val, truncated_rhs),
 150                 BinOp::Shr => {
 151                     if is_signed {
 152                         fx.bcx.ins().sshr(lhs_val, truncated_rhs)
 153                     } else {
 154                         fx.bcx.ins().ushr(lhs_val, truncated_rhs)
 155                     }
 156                 }
 157                 _ => unreachable!(),
 158             };
 159             if let Some(is_overflow) = is_overflow {
 160                 let out_ty = fx.tcx.mk_tup([lhs.layout().ty, fx.tcx.types.bool].iter());
 161                 Some(CValue::by_val_pair(val, is_overflow, fx.layout_of(out_ty)))
 162             } else {
 163                 Some(CValue::by_val(val, lhs.layout()))
 164             }
 165         }
 166     }
 167 }